Can community midwives prevent antenatal depression? An external pilot study to test the feasibility of a cluster randomized controlled universal prevention trial.

PubMed

Brugha, T S; Smith, J; Austin, J; Bankart, J; Patterson, M; Lovett, C; Morgan, Z; Morrell, C J; Slade, P

2016-01-01

Repeated epidemiological surveys show no decline in depression although uptake of treatments has grown. Universal depression prevention interventions are effective in schools but untested rigorously in adulthood. Selective prevention programmes have poor uptake. Universal interventions may be more acceptable during routine healthcare contacts for example antenatally. One study within routine postnatal healthcare suggested risk of postnatal depression could be reduced in non-depressed women from 11% to 8% by giving health visitors psychological intervention training. Feasibility and effectiveness in other settings, most notably antenatally, is unknown. We conducted an external pilot study using a cluster trial design consisting of recruitment and enhanced psychological training of randomly selected clusters of community midwives (CMWs), recruitment of pregnant women of all levels of risk of depression, collection of baseline and outcome data prior to childbirth, allowing time for women 'at increased risk' to complete CMW-provided psychological support sessions. Seventy-nine percent of eligible women approached agreed to take part. Two hundred and ninety-eight women in eight clusters participated and 186 termed 'at low risk' for depression, based on an Edinburgh Perinatal Depression Scale (EPDS) score of <12 at 12 weeks gestation, provided baseline and outcome data at 34 weeks gestation. All trial protocol procedures were shown to be feasible. Antenatal effect sizes in women 'at low risk' were similar to those previously demonstrated postnatally. Qualitative work confirmed the acceptability of the approach to CMWs and intervention group women. A fully powered trial testing universal prevention of depression in pregnancy is feasible, acceptable and worth undertaking.

Efficacy of a Universal Parent Training Program (HOPE-20): Cluster Randomized Controlled Trial

ERIC Educational Resources Information Center

Leung, Cynthia; Tsang, Sandra; Kwan, H. W.

2017-01-01

Objective: This study examined the efficacy of Hands-On Parent Empowerment-20 (HOPE-20) program. Methods: Eligible participants were parents residing in Hong Kong with target children aged 2 years attending nursery schools. Cluster randomized control trial was adopted, with 10 schools (110 participants) assigned to intervention group and 8 schools…

An exploratory cluster randomised trial of a university halls of residence based social norms marketing campaign to reduce alcohol consumption among 1st year students

PubMed Central

2013-01-01

Aims This exploratory trial examines the feasibility of implementing a social norms marketing campaign to reduce student drinking in universities in Wales, and evaluating it using cluster randomised trial methodology. Methods Fifty residence halls in 4 universities in Wales were randomly assigned to intervention or control arms. Web and paper surveys were distributed to students within these halls (n = 3800), assessing exposure/contamination, recall of and evaluative responses to intervention messages, perceived drinking norms and personal drinking behaviour. Measures included the Drinking Norms Rating Form, the Daily Drinking Questionnaire and AUDIT-C. Results A response rate of 15% (n = 554) was achieved, varying substantially between sites. Intervention posters were seen by 80% and 43% of students in intervention and control halls respectively, with most remaining materials seen by a minority in both groups. Intervention messages were rated as credible and relevant by little more than half of students, though fewer felt they would influence their behaviour, with lighter drinkers more likely to perceive messages as credible. No differences in perceived norms were observed between intervention and control groups. Students reporting having seen intervention materials reported lower descriptive and injunctive norms than those who did not. Conclusions Attention is needed to enhancing exposure, credibility and perceived relevance of intervention messages, particularly among heavier drinkers, before definitive evaluation can be recommended. A definitive evaluation would need to consider how it would achieve sufficient response rates, whilst hall-level cluster randomisation appears subject to a significant degree of contamination. Trial registration ISRCTN: ISRCTN48556384 PMID:23594918

Avulsion Clusters in Alluvial Systems: An Example of Large-Scale Self-Organization in Ancient and Experimental Basins

NASA Astrophysics Data System (ADS)

Hajek, E.; Heller, P.; Huzurbazar, S.; Sheets, B.; Paola, C.

2006-12-01

The stratigraphic record of at least some alluvial basins exhibits a spatial structure that may reflect long time- scale (103-105 yr in natural basins) autogenic organization of river avulsions. Current models of avulsion-dominated alluvial sequences emphasize the spatial and temporal distribution of coarse-grained channel-belt deposits amid fine-grained floodplain materials. These models typically assume that individual avulsions move, either randomly or deterministically, to low spots distributed throughout the model space. However, our observations of ancient deposits and experimental stratigraphy indicate a previously unrecognized pattern of channel-belt organization, where clusters of closely-spaced channel-belt deposits are separated from each other by extensive intervals of overbank deposits. We explore potential causes of and controls on avulsion clustering with outcrop and subsurface data from Late Cretaceous/Early Paleogene fluvial deposits in the Rocky Mountains (including the Ferris, Lance, and Fort Union formations of Wyoming) and results of physical stratigraphy experiments from the St. Anthony Falls Lab, University of Minnesota. We use Ripley's K-function to determine the degree and scales of clustering in these basins with results that show moderate statistical clustering in experimental deposits and strong clustering in the Ferris Formation (Hanna Basin, Wyoming). External controls (base level, subsidence rate, and sediment/water supplies) were not varied during the experiment, and therefore not factors in cluster formation. Likewise, the stratigraphic context of the ancient system (including the absence of incised valleys and lack of faulting) suggests that obvious extrinsic controls, such as base level change and local tectonics, were not major influences on the development of clusters. We propose that avulsion clusters, as seen in this study, reflect a scale of self-organization in alluvial basins that is not usually recognized in stratigraphy. However cursory examination of other ancient systems suggests that such structure may be common in the rock record. Understanding mechanisms driving avulsion clustering will shed light on the dominant processes in alluvial basins over long time scales. Furthermore, characterizing autogenic avulsion clusters will be an important factor to consider when interpreting allogenic signals in ancient basin fills.

A cluster-randomised controlled trial integrating a community-based water, sanitation and hygiene programme, with mass distribution of albendazole to reduce intestinal parasites in Timor-Leste: the WASH for WORMS research protocol.

PubMed

Nery, Susana Vaz; McCarthy, James S; Traub, Rebecca; Andrews, Ross M; Black, Jim; Gray, Darren; Weking, Edmund; Atkinson, Jo-An; Campbell, Suzy; Francis, Naomi; Vallely, Andrew; Williams, Gail; Clements, Archie

2015-12-30

There is limited evidence demonstrating the benefits of community-based water, sanitation and hygiene (WASH) programmes on infections with soil-transmitted helminths (STH) and intestinal protozoa. Our study aims to contribute to that evidence base by investigating the effectiveness of combining two complementary approaches for control of STH: periodic mass administration of albendazole, and delivery of a community-based WASH programme. WASH for WORMS is a cluster-randomised controlled trial to test the hypothesis that a community-based WASH intervention integrated with periodic mass distribution of albendazole will be more effective in reducing infections with STH and protozoa than mass deworming alone. All 18 participating rural communities in Timor-Leste receive mass chemotherapy every 6 months. Half the communities also receive the community-based WASH programme. Primary outcomes are the cumulative incidence of infection with STH. Secondary outcomes include the prevalence of protozoa; intensity of infection with STH; as well as morbidity indicators (anaemia, stunting and wasting). Each of the trial outcomes will be compared between control and intervention communities. End points will be measured 2 years after the first albendazole distribution; and midpoints are measured at 6 months intervals (12 months for haemoglobin and anthropometric indexes). Mixed-methods research will also be conducted in order to identify barriers and enablers associated with the acceptability and uptake of the WASH programme. Ethics approval was obtained from the human ethics committees at the University of Queensland, Australian National University, Timorese Ministry of Health, and University of Melbourne. The results of the trial will be published in peer-reviewed journals presented at national and international conferences, and disseminated to relevant stakeholders in health and WASH programmes. This study is funded by a Partnership for Better Health--Project grant from the National Health and Research Council (NHMRC), Australia. ACTRN12614000680662; Pre-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

A cluster-randomised controlled trial integrating a community-based water, sanitation and hygiene programme, with mass distribution of albendazole to reduce intestinal parasites in Timor-Leste: the WASH for WORMS research protocol

PubMed Central

Nery, Susana Vaz; McCarthy, James S; Traub, Rebecca; Andrews, Ross M; Black, Jim; Gray, Darren; Weking, Edmund; Atkinson, Jo-An; Campbell, Suzy; Francis, Naomi; Vallely, Andrew; Williams, Gail; Clements, Archie

2015-01-01

Introduction There is limited evidence demonstrating the benefits of community-based water, sanitation and hygiene (WASH) programmes on infections with soil-transmitted helminths (STH) and intestinal protozoa. Our study aims to contribute to that evidence base by investigating the effectiveness of combining two complementary approaches for control of STH: periodic mass administration of albendazole, and delivery of a community-based WASH programme. Methods and analysis WASH for WORMS is a cluster-randomised controlled trial to test the hypothesis that a community-based WASH intervention integrated with periodic mass distribution of albendazole will be more effective in reducing infections with STH and protozoa than mass deworming alone. All 18 participating rural communities in Timor-Leste receive mass chemotherapy every 6 months. Half the communities also receive the community-based WASH programme. Primary outcomes are the cumulative incidence of infection with STH. Secondary outcomes include the prevalence of protozoa; intensity of infection with STH; as well as morbidity indicators (anaemia, stunting and wasting). Each of the trial outcomes will be compared between control and intervention communities. End points will be measured 2 years after the first albendazole distribution; and midpoints are measured at 6 months intervals (12 months for haemoglobin and anthropometric indexes). Mixed-methods research will also be conducted in order to identify barriers and enablers associated with the acceptability and uptake of the WASH programme. Ethics and dissemination Ethics approval was obtained from the human ethics committees at the University of Queensland, Australian National University, Timorese Ministry of Health, and University of Melbourne. The results of the trial will be published in peer-reviewed journals presented at national and international conferences, and disseminated to relevant stakeholders in health and WASH programmes. This study is funded by a Partnership for Better Health—Project grant from the National Health and Research Council (NHMRC), Australia. Trial registration number ACTRN12614000680662; Pre-results PMID:26719316

Quantity, topics, methods and findings of randomised controlled trials published by German university departments of general practice - systematic review.

PubMed

Heinmüller, Stefan; Schneider, Antonius; Linde, Klaus

2016-04-23

Academic infrastructures and networks for clinical research in primary care receive little funding in Germany. We aimed to provide an overview of the quantity, topics, methods and findings of randomised controlled trials published by German university departments of general practice. We searched Scopus (last search done in April 2015), publication lists of institutes and references of included articles. We included randomised trials published between January 2000 and December 2014 with a first or last author affiliated with a German university department of general practice or family medicine. Risk of bias was assessed with the Cochrane tool, and study findings were quantified using standardised mean differences (SMDs). Thirty-three trials met the inclusion criteria. Seventeen were cluster-randomised trials, with a majority investigating interventions aimed at improving processes compared with usual care. Sample sizes varied between 6 and 606 clusters and 168 and 7807 participants. The most frequent methodological problem was risk of selection bias due to recruitment of individuals after randomisation of clusters. Effects of interventions over usual care were mostly small (SMD <0.3). Sixteen trials randomising individual participants addressed a variety of treatment and educational interventions. Sample sizes varied between 20 and 1620 participants. The methodological quality of the trials was highly variable. Again, effects of experimental interventions over controls were mostly small. Despite limited funding, German university institutes of general practice or family medicine are increasingly performing randomised trials. Cluster-randomised trials on practice improvement are a focus, but problems with allocation concealment are frequent.

The CLIMATE schools combined study: a cluster randomised controlled trial of a universal Internet-based prevention program for youth substance misuse, depression and anxiety

PubMed Central

2014-01-01

Background Anxiety, depressive and substance use disorders account for three quarters of the disability attributed to mental disorders and frequently co-occur. While programs for the prevention and reduction of symptoms associated with (i) substance use and (ii) mental health disorders exist, research is yet to determine if a combined approach is more effective. This paper describes the study protocol of a cluster randomised controlled trial to evaluate the effectiveness of the CLIMATE Schools Combined intervention, a universal approach to preventing substance use and mental health problems among adolescents. Methods/design Participants will consist of approximately 8400 students aged 13 to 14-years-old from 84 secondary schools in New South Wales, Western Australia and Queensland, Australia. The schools will be cluster randomised to one of four groups; (i) CLIMATE Schools Combined intervention; (ii) CLIMATE Schools - Substance Use; (iii) CLIMATE Schools - Mental Health, or (iv) Control (Health and Physical Education as usual). The primary outcomes of the trial will be the uptake and harmful use of alcohol and other drugs, mental health symptomatology and anxiety, depression and substance use knowledge. Secondary outcomes include substance use related harms, self-efficacy to resist peer pressure, general disability, and truancy. The link between personality and substance use will also be examined. Discussion Compared to students who receive the universal CLIMATE Schools - Substance Use, or CLIMATE Schools - Mental Health or the Control condition (who received usual Health and Physical Education), we expect students who receive the CLIMATE Schools Combined intervention to show greater delays to the initiation of substance use, reductions in substance use and mental health symptoms, and increased substance use and mental health knowledge. Trial registration This trial is registered with the Australian and New Zealand Clinical Trials registry, ACTRN12613000723785. PMID:24499060

A video-based transdiagnostic REBT universal prevention program for internalizing problems in adolescents: study protocol of a cluster randomized controlled trial.

PubMed

Păsărelu, Costina Ruxandra; Dobrean, Anca

2018-04-13

Internalizing problems are the most prevalent mental health problems in adolescents. Transdiagnostic programs are promising manners to treat multiple problems within the same protocol, however, there is limited research regarding the efficacy of such programs delivered as universal prevention programs in school settings. Therefore, the present study aims to investigate the efficacy of a video-based transdiagnostic rational emotive behavioral therapy (REBT) universal prevention program, for internalizing problems. The second objective of the present paper will be to investigate the subsequent mechanisms of change, namely maladaptive cognitions. A two-arm parallel randomized controlled trial will be conducted, with two groups: a video-based transdiagnostic REBT universal prevention program and a wait list control. Power analysis indicated that the study will involve 338 participants. Adolescents with ages between 12 and 17 years old, from several middle schools and high schools, will be invited to participate. Assessments will be conducted at four time points: baseline (T 1 ), post-intervention (T 2 ), 3 months follow-up (T 3 ) and 12 months follow-up (T 4 ). Intent-to-treat analysis will be used in order to investigate significant differences between the two groups in both primary and secondary outcomes. This is the first randomized controlled trial that aims to investigate the efficacy and mechanisms of change of a video-based transdiagnostic REBT universal prevention program, delivered in a school context. The present study has important implications for developing efficient prevention programs, interactive, that will aim to target within the same protocol both anxiety and depressive symptoms. ClinicalTrials.gov: NCT02756507 . Registered on 25 April 2016.

HUBBLE PINPOINTS WHITE DWARFS IN GLOBULAR CLUSTER

NASA Technical Reports Server (NTRS)

2002-01-01

Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope uncovered the oldest burned-out stars in our Milky Way Galaxy. Located in the globular cluster M4, these small, dying stars - called white dwarfs - are giving astronomers a fresh reading on one of the biggest questions in astronomy: How old is the universe? The ancient white dwarfs in M4 are about 12 to 13 billion years old. After accounting for the time it took the cluster to form after the big bang, astronomers found that the age of the white dwarfs agrees with previous estimates for the universe's age. In the top panel, a ground-based observatory snapped a panoramic view of the entire cluster, which contains several hundred thousand stars within a volume of 10 to 30 light-years across. The Kitt Peak National Observatory's 0.9-meter telescope took this picture in March 1995. The box at left indicates the region observed by the Hubble telescope. The Hubble telescope studied a small region of the cluster. A section of that region is seen in the picture at bottom left. A sampling of an even smaller region is shown at bottom right. This region is only about one light-year across. In this smaller region, Hubble pinpointed a number of faint white dwarfs. The blue circles pinpoint the dwarfs. It took nearly eight days of exposure time over a 67-day period to find these extremely faint stars. Globular clusters are among the oldest clusters of stars in the universe. The faintest and coolest white dwarfs within globular clusters can yield a globular cluster's age. Earlier Hubble observations showed that the first stars formed less than 1 billion years after the universe's birth in the big bang. So, finding the oldest stars puts astronomers within arm's reach of the universe's age. M4 is 7,000 light-years away in the constellation Scorpius. Hubble's Wide Field and Planetary Camera 2 made the observations from January through April 2001. These optical observations were combined to create the above images. Spectral data were also taken. Credit for Hubble telescope photos: NASA and H. Richer (University of British Columbia) Credit for ground-based photo: NOAO/AURA/NSF

Universal quantum computation with temporal-mode bilayer square lattices

NASA Astrophysics Data System (ADS)

Alexander, Rafael N.; Yokoyama, Shota; Furusawa, Akira; Menicucci, Nicolas C.

2018-03-01

We propose an experimental design for universal continuous-variable quantum computation that incorporates recent innovations in linear-optics-based continuous-variable cluster state generation and cubic-phase gate teleportation. The first ingredient is a protocol for generating the bilayer-square-lattice cluster state (a universal resource state) with temporal modes of light. With this state, measurement-based implementation of Gaussian unitary gates requires only homodyne detection. Second, we describe a measurement device that implements an adaptive cubic-phase gate, up to a random phase-space displacement. It requires a two-step sequence of homodyne measurements and consumes a (non-Gaussian) cubic-phase state.

Do We Really Have an Age/H_0 Conflict?

NASA Astrophysics Data System (ADS)

Baum, W. A.

1997-12-01

Two independent methods for estimating the age of the universe can both be linked to the absolute magnitudes of the RR Lyrae stars, one based on stellar evolution in globular clusters and the other based on the Hubble Constant derived from globular clusters as distance indicators. The latter has recently been extracted from HST-WFPC2 data for globular clusters in the Coma Cluster galaxy IC 4051 (Baum et al. 1997, AJ, 113, 1483). If RR Lyrae stars are brighter than we have previously thought, the stellar-evolution age estimate is shortened whereas the Hubble age is increased, so we can ask a very simple question: For what RR Lyrae magnitude zero point would the stellar-evolution age coincide with the Hubble age, and is it a reasonable value? Allowing 1 Gyr for globular clusters to have formed, and assuming a classical Einstein-deSitter universe with Lambda = 0, I find the two ages to coincide if M_V(RR) ~ 0.16[Fe/H] + 0.46, which (among other things) puts the Large Magellanic Cloud at (m-M) = 18.78 +/- 0.17 mag. The implied age of the universe is 11.0 +/- 1.4 Gyr, and the corresponding H_0 = 59 +/- 8 km/s per Mpc.

Nanoscale Materials and Architectures for Energy Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grulke, Eric A.; Sunkara, Mahendra K.

2011-05-25

The Kentucky EPSCoR Program supported an inter-university, multidisciplinary energy-related research cluster studying nanomaterials for converting solar radiation and residual thermal energy to electrical energy and hydrogen. It created a collaborative center of excellence based on research expertise in nanomaterials, architectures, and their synthesis. The project strengthened and improved the collaboration between the University of Louisville, the University of Kentucky, and NREL. The cluster hired a new faculty member for ultra-fast transient spectroscopy, and enabled the mentoring of one research scientist, two postdoctoral scholars and ten graduate students. Work was accomplished with three focused cluster projects: organic and photoelectrochemical solar cells,more » solar fuels, and thermionic energy conversion.« less

Radiation hydrodynamics of super star cluster formation

NASA Astrophysics Data System (ADS)

Tsang, Benny Tsz Ho; Milos Milosavljevic

2018-01-01

Throughout the history of the Universe, the nuclei of super star clusters represent the most active sites for star formation. The high densities of massive stars within the clusters produce intense radiation that imparts both energy and momentum on the surrounding star-forming gas. Theoretical claims based on idealized geometries have claimed the dominant role of radiation pressure in controlling the star formation activity within the clusters. In order for cluster formation simulations to be reliable, numerical schemes have to be able to model accurately the radiation flows through the gas clumps at the cluster nuclei with high density contrasts. With a hybrid Monte Carlo radiation transport module we developed, we performed 3D radiation hydrodynamical simulations of super star cluster formation in turbulent clouds. Furthermore, our Monte Carlo radiation treatment provides a native capability to produce synthetic observations, which allows us to predict observational indicators and to inform future observations. We found that radiation pressure has definite, but minor effects on limiting the gas supply for star formation, and the final mass of the most massive cluster is about one million solar masses. The ineffective forcing was due to the density variations inside the clusters, i.e. radiation takes the paths of low densities and avoids forcing on dense clumps. Compared to a radiation-free control run, we further found that the presence of radiation amplifies the density variations. The core of the resulting cluster has a high stellar density, about the threshold required for stellar collisions and merging. The very massive star that form from the stellar merging could continue to gain mass from the surrounding gas reservoir that is gravitationally confined by the deep potential of the cluster, seeding the potential formation of a massive black hole.

Unusual clustering of coefficients of variation in published articles from a medical biochemistry department in India.

PubMed

Hudes, Mark L; McCann, Joyce C; Ames, Bruce N

2009-03-01

A simple statistical method is described to test whether data are consistent with minimum statistical variability expected in a biological experiment. The method is applied to data presented in data tables in a subset of 84 articles among more than 200 published by 3 investigators in a small medical biochemistry department at a major university in India and to 29 "control" articles selected by key word PubMed searches. Major conclusions include: 1) unusual clustering of coefficients of variation (CVs) was observed for data from the majority of articles analyzed that were published by the 3 investigators from 2000-2007; unusual clustering was not observed for data from any of their articles examined that were published between 1992 and 1999; and 2) among a group of 29 control articles retrieved by PubMed key word, title, or title/abstract searches, unusually clustered CVs were observed in 3 articles. Two of these articles were coauthored by 1 of the 3 investigators, and 1 was from the same university but a different department. We are unable to offer a statistical or biological explanation for the unusual clustering observed.

Generalized Self-Organizing Maps for Automatic Determination of the Number of Clusters and Their Multiprototypes in Cluster Analysis.

PubMed

Gorzalczany, Marian B; Rudzinski, Filip

2017-06-07

This paper presents a generalization of self-organizing maps with 1-D neighborhoods (neuron chains) that can be effectively applied to complex cluster analysis problems. The essence of the generalization consists in introducing mechanisms that allow the neuron chain--during learning--to disconnect into subchains, to reconnect some of the subchains again, and to dynamically regulate the overall number of neurons in the system. These features enable the network--working in a fully unsupervised way (i.e., using unlabeled data without a predefined number of clusters)--to automatically generate collections of multiprototypes that are able to represent a broad range of clusters in data sets. First, the operation of the proposed approach is illustrated on some synthetic data sets. Then, this technique is tested using several real-life, complex, and multidimensional benchmark data sets available from the University of California at Irvine (UCI) Machine Learning repository and the Knowledge Extraction based on Evolutionary Learning data set repository. A sensitivity analysis of our approach to changes in control parameters and a comparative analysis with an alternative approach are also performed.

The Children and Parents in Focus project: a population-based cluster-randomised controlled trial to prevent behavioural and emotional problems in children

PubMed Central

2013-01-01

Background There is large body of knowledge to support the importance of early interventions to improve child health and development. Nonetheless, it is important to identify cost-effective blends of preventive interventions with adequate coverage and feasible delivery modes. The aim of the Children and Parents in Focus trial is to compare two levels of parenting programme intensity and rate of exposure, with a control condition to address impact and cost-effectiveness of a universally offered evidence-based parenting programme in the Swedish context. Methods/Design The trial has a cluster randomised controlled design comprising three arms: Universal arm (with access to participation in Triple P - Positive Parenting Program, level 2); Universal Plus arm (with access to participation in Triple P - Positive Parenting Program, level 2 as well as level 3, and level 4 group); and Services as Usual arm. The sampling frame is Uppsala municipality in Sweden. Child health centres consecutively recruit parents of children aged 3 to 5 years before their yearly check-ups (during the years 2013–2017). Outcomes will be measured annually. The primary outcome will be children’s behavioural and emotional problems as rated by three informants: fathers, mothers and preschool teachers. The other outcomes will be parents’ behaviour and parents’ general health. Health economic evaluations will analyse cost-effectiveness of the interventions versus care as usual by comparing the costs and consequences in terms of impact on children’s mental health, parent’s mental health and health-related quality of life. Discussion This study addresses the need for comprehensive evaluation of the long-term effects, costs and benefits of early parenting interventions embedded within existing systems. In addition, the study will generate population-based data on the mental health and well-being of preschool aged children in Sweden. Trial registration ISRCTN: ISRCTN16513449. PMID:24131587

Use of machine learning methods to classify Universities based on the income structure

NASA Astrophysics Data System (ADS)

Terlyga, Alexandra; Balk, Igor

2017-10-01

In this paper we discuss use of machine learning methods such as self organizing maps, k-means and Ward’s clustering to perform classification of universities based on their income. This classification will allow us to quantitate classification of universities as teaching, research, entrepreneur, etc. which is important tool for government, corporations and general public alike in setting expectation and selecting universities to achieve different goals.

FAR-FLUNG GALAXY CLUSTERS MAY REVEAL FATE OF UNIVERSE

NASA Technical Reports Server (NTRS)

2002-01-01

A selection of NASA Hubble Space Telescope snapshots of huge galaxy clusters that lie far away and far back in time. These are selected from a catalog of 92 new clusters uncovered during a six-year Hubble observing program known as the Medium Deep Survey. If the distances and masses of the clusters are confirmed by ground based telescopes, the survey may hold clues to how galaxies quickly formed into massive large-scale structures after the big bang, and what that may mean for the eventual fate of the expanding universe. The images are each a combination of two exposures in yellow and deep red taken with Hubble's Wide Field and Planetary Camera 2. Each cluster's distance is inferred from the reddening of the starlight, which is due to the expansion of space. Astronomers assume these clusters all formed early in the history of the universe. HST133617-00529 (left) This collection of spiral and elliptical galaxies lies an estimated 4 to 6 billion light-years away. It is in the constellation of Virgo not far from the 3rd magnitude star Zeta Virginis. The brighter galaxies in this cluster have red magnitudes between 20 and 22 near the limit of the Palomar Sky Survey. The bright blue galaxy (upper left) is probably a foreground galaxy, and not a cluster member. The larger of the galaxies in the cluster are probably about the size of our Milky Way Galaxy. The diagonal line at lower right is an artificial satellite trail. HST002013+28366 (upper right) This cluster of galaxies lies in the constellation of Andromeda a few degrees from the star Alpheratz in the northeast corner of the constellation Pegasus. It is at an estimated distance of 4 billion light-years, which means the light we are seeing from the cluster is as it appeared when the universe was roughly 2/3 of its present age. HST035528+09435 (lower right) At an estimated distance of about 7 to 10 billion light-years (z=1), this is one of the farthest clusters in the Hubble sample. The cluster lies in the constellation of Taurus. Credit: K. Ratnatunga, R. Griffiths (Carnegie Mellon University); and NASA

Exponents of non-linear clustering in scale-free one-dimensional cosmological simulations

NASA Astrophysics Data System (ADS)

Benhaiem, David; Joyce, Michael; Sicard, François

2013-03-01

One-dimensional versions of dissipationless cosmological N-body simulations have been shown to share many qualitative behaviours of the three-dimensional problem. Their interest lies in the fact that they can resolve a much greater range of time and length scales, and admit exact numerical integration. We use such models here to study how non-linear clustering depends on initial conditions and cosmology. More specifically, we consider a family of models which, like the three-dimensional Einstein-de Sitter (EdS) model, lead for power-law initial conditions to self-similar clustering characterized in the strongly non-linear regime by power-law behaviour of the two-point correlation function. We study how the corresponding exponent γ depends on the initial conditions, characterized by the exponent n of the power spectrum of initial fluctuations, and on a single parameter κ controlling the rate of expansion. The space of initial conditions/cosmology divides very clearly into two parts: (1) a region in which γ depends strongly on both n and κ and where it agrees very well with a simple generalization of the so-called stable clustering hypothesis in three dimensions; and (2) a region in which γ is more or less independent of both the spectrum and the expansion of the universe. The boundary in (n, κ) space dividing the `stable clustering' region from the `universal' region is very well approximated by a `critical' value of the predicted stable clustering exponent itself. We explain how this division of the (n, κ) space can be understood as a simple physical criterion which might indeed be expected to control the validity of the stable clustering hypothesis. We compare and contrast our findings to results in three dimensions, and discuss in particular the light they may throw on the question of `universality' of non-linear clustering in this context.

Developing the “Control Identity” Typology to Create More Effective Testicular Health Promotional Messaging

PubMed Central

Rovito, Michael J.; Gordon, Thomas F.; Bass, Sarah B.; DuCette, Joseph; Tierney, Ashley M.; Coles, Nicholas

2015-01-01

Testicular self-examination (TSE) promotional interventions historically operate without a theoretical framework, which negatively influences their effectiveness. As TSE is critical to the early detection of testicular cancer, this behavior is an essential component to improving overall male well-being. To address this need, the Control Identity personality typology was developed to assist in creating more effective TSE promotional interventions. Four outcome control dispositions were defined a priori based on the dimensions of illusions of control and locus of control. An original 41-item survey, the Control Identity Assessment Scale, was used to assess perceived vulnerability, value of health promotion, and health outcome control among a convenience sample of 300 university males aged 18 to 35 years via a cross-sectional research design. Factor and cluster analyses were employed to extract salient factors in the data and to identify subgroups within the sample. A consistent five-factor structure matrix (~70% explained variance) served as the foundation from which a k-means cluster analysis was employed to classify four types of individuals. Significant differences were detected between clusters on primary variables, including behavioral intentions to conduct TSE. The Control Identity typology aims to provide the needed mechanism for health practitioners to create more effective preventive health messaging to promote TSE. Future implications on employing this typology to segment audiences in order to increase overall effectiveness are offered. Application of this typology could ultimately lead to increasing TSE knowledge retention, behavioral intentions, actual performance, and adherence. PMID:26669773

Quantum Computational Universality of the 2D Cai-Miyake-D"ur-Briegel Quantum State

NASA Astrophysics Data System (ADS)

Wei, Tzu-Chieh; Raussendorf, Robert; Kwek, Leong Chuan

2012-02-01

Universal quantum computation can be achieved by simply performing single-qubit measurements on a highly entangled resource state, such as cluster states. Cai, Miyake, D"ur, and Briegel recently constructed a ground state of a two-dimensional quantum magnet by combining multiple Affleck-Kennedy-Lieb-Tasaki quasichains of mixed spin-3/2 and spin-1/2 entities and by mapping pairs of neighboring spin-1/2 particles to individual spin-3/2 particles [Phys. Rev. A 82, 052309 (2010)]. They showed that this state enables universal quantum computation by constructing single- and two-qubit universal gates. Here, we give an alternative understanding of how this state gives rise to universal measurement-based quantum computation: by local operations, each quasichain can be converted to a one-dimensional cluster state and entangling gates between two neighboring logical qubits can be implemented by single-spin measurements. Furthermore, a two-dimensional cluster state can be distilled from the Cai-Miyake-D"ur-Briegel state.

Evaluation of a multimodal school-based depression and suicide prevention program among Dutch adolescents: design of a cluster-randomized controlled trial.

PubMed

Gijzen, Mandy W M; Creemers, Daan H M; Rasing, Sanne P A; Smit, Filip; Engels, Rutger C M E

2018-05-10

Since 2010, suicide has been the most important cause of mortality in youth aged 15 to 29 years in the Netherlands. Depression is an important risk factor for suicidal behaviors (i.e., suicide ideation, deliberate self-harm, planning, and suicide attempts) in adolescents. Adolescents who develop depressive symptoms, are also at risk for adult depression. This developmental continuity is especially noticeable in adolescents compared to other age groups; therefore, it is necessary to develop preventive strategies for teens. This study will test a multimodal school-based approach to suicide and depression prevention, which integrates universal and targeted approaches and includes various stakeholders (schools, adolescents, parents, and mental health professionals) simultaneously. We will perform a cluster randomized controlled trial (RCT) with an intervention and control condition to test the effectiveness of a school-based multimodal stepped-prevention program for depression and suicidal behaviors in adolescents. Adolescents in their second year of secondary education will participate in the study. The participants in the intervention condition will receive the entire multimodal stepped-preventive program comprising early screening and detection of suicidal behaviors and depressive symptoms, a safety net consisting of gatekeepers at school, followed by universal and indicated prevention. The participants in the control condition will undergo only the screening and the safety net of gatekeepers at schools. They will complete assessments at baseline, post-intervention, and 6, 12, and 24-month follow-up. Primary outcome will be suicidal behaviors measured at 12-months follow-up. Additionally, the present study will identify mechanisms that mediate and moderate the program effects and test the effect of the program on various secondary outcomes. If the school-based multimodal stepped-prevention program proves to be effective, it could be implemented in schools on a large scale. The study is registered in the Dutch Trial Register ( NTR6622 ).

Effectiveness of a pragmatic school-based universal intervention targeting student resilience protective factors in reducing mental health problems in adolescents.

PubMed

Dray, Julia; Bowman, Jenny; Campbell, Elizabeth; Freund, Megan; Hodder, Rebecca; Wolfenden, Luke; Richards, Jody; Leane, Catherine; Green, Sue; Lecathelinais, Christophe; Oldmeadow, Christopher; Attia, John; Gillham, Karen; Wiggers, John

2017-06-01

Worldwide, 10-20% of adolescents experience mental health problems. Strategies aimed at strengthening resilience protective factors provide a potential approach for reducing mental health problems in adolescents. This study evaluated the effectiveness of a universal, school-based intervention targeting resilience protective factors in reducing mental health problems in adolescents. A cluster randomised controlled trial was conducted in 20 intervention and 12 control secondary schools located in socio-economically disadvantaged areas of NSW, Australia. Data were collected from 3115 students at baseline (Grade 7, 2011), of whom 2149 provided data at follow up (Grade 10, 2014; enrolments in Grades 7 to 10 typically aged 12-16 years; 50% male; 69.0% retention). There were no significant differences between groups at follow-up for three mental health outcomes: total SDQ, internalising problems, and prosocial behaviour. A small statistically significant difference in favour of the control group was found for externalising problems. Findings highlight the continued difficulties in developing effective, school-based prevention programs for mental health problems in adolescents. ANZCTR (Ref no: ACTRN12611000606987). Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Providing NHS staff with height-adjustable workstations and behaviour change strategies to reduce workplace sitting time: protocol for the Stand More AT (SMArT) Work cluster randomised controlled trial.

PubMed

O'Connell, S E; Jackson, B R; Edwardson, C L; Yates, T; Biddle, S J H; Davies, M J; Dunstan, D; Esliger, D; Gray, L; Miller, P; Munir, F

2015-12-09

High levels of sedentary behaviour (i.e., sitting) are a risk factor for poor health. With high levels of sitting widespread in desk-based office workers, office workplaces are an appropriate setting for interventions aimed at reducing sedentary behaviour. This paper describes the development processes and proposed intervention procedures of Stand More AT (SMArT) Work, a multi-component randomised control (RCT) trial which aims to reduce occupational sitting time in desk-based office workers within the National Health Service (NHS). SMArT Work consists of 2 phases: 1) intervention development: The development of the SMArT Work intervention takes a community-based participatory research approach using the Behaviour Change Wheel. Focus groups will collect detailed information to gain a better understanding of the most appropriate strategies, to sit alongside the provision of height-adjustable workstations, at the environmental, organisational and individual level that support less occupational sitting. 2) intervention delivery and evaluation: The 12 month cluster RCT aims to reduce workplace sitting in the University Hospitals of Leicester NHS Trust. Desk-based office workers (n = 238) will be randomised to control or intervention clusters, with the intervention group receiving height-adjustable workstations and supporting techniques based on the feedback received from the development phase. Data will be collected at four time points; baseline, 3, 6 and 12 months. The primary outcome is a reduction in sitting time, measured by the activPAL(TM) micro at 12 months. Secondary outcomes include objectively measured physical activity and a variety of work-related health and psycho-social measures. A process evaluation will also take place. This study will be the first long-term, evidence-based, multi-component cluster RCT aimed at reducing occupational sitting within the NHS. This study will help form a better understanding and knowledge base of facilitators and barriers to creating a healthier work environment and contribute to health and wellbeing policy. ISRCTN10967042 . Registered 2 February 2015.

A study of hierarchical clustering of galaxies in an expanding universe

NASA Astrophysics Data System (ADS)

Porter, D. H.

The nonlinear hierarchical clustering of galaxies in an Einstein-deSitter (Omega = 1), initially white noise mass fluctuations (n = 0) model universe is investigated and shown to be in contradiction with previous results. The model is done in terms of an 11,000-body numerical simulation. The independent statics of 0.72 million particles are used to simulte the boundary conditions. A new method for integrating the Newtonian N-body gravity equations, which has controllable accuracy, incorporates a recursive center of mass reduction, and regularizes two body encounters is used to do the simulation. The coordinate system used here is well suited for the investigation of galaxy clustering, incorporating the independent positions and velocities of an arbitrary number of particles into a logarithmic hierarchy of center of mass nodes. The boundary for the simulation is created by using this hierarchy to map the independent statics of 0.72 million particles into just 4,000 particles. This method for simulating the boundary conditions also has controllable accuracy.

Postgraduate Taught Portfolio Review--The Cluster Approach, Non-Subject-Based Grouping of Courses and Relevant Performance Indicators

ERIC Educational Resources Information Center

Konstantinidis-Pereira, Alicja

2018-01-01

This paper summarises a new method of grouping postgraduate taught (PGT) courses introduced at Oxford Brookes University as a part of a Portfolio Review. Instead of classifying courses by subject, the new cluster approach uses statistical methods to group the courses based on factors including flexibility of study options, level of specialisation,…

Community-based physical activity and nutrition programme for adults with metabolic syndrome in Vietnam: study protocol for a cluster-randomised controlled trial

PubMed Central

Tran, Van Dinh; Lee, Andy H; Jancey, Jonine; James, Anthony P; Howat, Peter; Thi Phuong Mai, Le

2016-01-01

Introduction Metabolic syndrome (MetS) is a cluster of risk factors for cardiovascular diseases and type II diabetes. In Vietnam, more than one-quarter of its population aged 50–65 have MetS. This cluster-randomised controlled trial aims to evaluate the effectiveness of interventions to increase levels of physical activity and improve dietary behaviours among Vietnamese adults aged 50–65 years with MetS. Method and analysis This 6-month community-based intervention includes a range of strategies to improve physical activity and nutrition for adults with MetS in Hanam, a province located in northern Vietnam. 600 participants will be recruited from 6 communes with 100 participants per commune. The 6 selected communes will be randomly allocated to either an intervention group (m=3; n=300) or a control group (m=3; n=300). The intervention comprises booklets, education sessions, resistance bands and attending local walking groups that provide information and encourage participants to improve their physical activity and healthy eating behaviours during the 6-month period. The control group participants will receive standard and 1-time advice. Social cognitive theory is the theoretical concept underpinning this study. Measurements will be taken at baseline and postintervention to evaluate programme effectiveness. Ethics and dissemination The research protocol was approved by the Curtin University Human Research Ethics Committee (approval number: HR139/2014). The results of the study will be disseminated through publications, reports and conference presentations. Trial registration number ACTRN12614000811606. PMID:27256094

An Energy Centric Cluster-Based Routing Protocol for Wireless Sensor Networks.

PubMed

Hosen, A S M Sanwar; Cho, Gi Hwan

2018-05-11

Clustering is an effective way to prolong the lifetime of a wireless sensor network (WSN). The common approach is to elect cluster heads to take routing and controlling duty, and to periodically rotate each cluster head's role to distribute energy consumption among nodes. However, a significant amount of energy dissipates due to control messages overhead, which results in a shorter network lifetime. This paper proposes an energy-centric cluster-based routing mechanism in WSNs. To begin with, cluster heads are elected based on the higher ranks of the nodes. The rank is defined by residual energy and average distance from the member nodes. With the role of data aggregation and data forwarding, a cluster head acts as a caretaker for cluster-head election in the next round, where the ranks' information are piggybacked along with the local data sending during intra-cluster communication. This reduces the number of control messages for the cluster-head election as well as the cluster formation in detail. Simulation results show that our proposed protocol saves the energy consumption among nodes and achieves a significant improvement in the network lifetime.

An Energy Centric Cluster-Based Routing Protocol for Wireless Sensor Networks

PubMed Central

Hosen, A. S. M. Sanwar; Cho, Gi Hwan

2018-01-01

Clustering is an effective way to prolong the lifetime of a wireless sensor network (WSN). The common approach is to elect cluster heads to take routing and controlling duty, and to periodically rotate each cluster head’s role to distribute energy consumption among nodes. However, a significant amount of energy dissipates due to control messages overhead, which results in a shorter network lifetime. This paper proposes an energy-centric cluster-based routing mechanism in WSNs. To begin with, cluster heads are elected based on the higher ranks of the nodes. The rank is defined by residual energy and average distance from the member nodes. With the role of data aggregation and data forwarding, a cluster head acts as a caretaker for cluster-head election in the next round, where the ranks’ information are piggybacked along with the local data sending during intra-cluster communication. This reduces the number of control messages for the cluster-head election as well as the cluster formation in detail. Simulation results show that our proposed protocol saves the energy consumption among nodes and achieves a significant improvement in the network lifetime. PMID:29751663

Controlled and Uncontrolled Subject Descriptions in the CF Database: A Comparison of Optimal Cluster-Based Retrieval Results.

ERIC Educational Resources Information Center

Shaw, W. M., Jr.

1993-01-01

Describes a study conducted on the cystic fibrosis (CF) database, a subset of MEDLINE, that investigated clustering structure and the effectiveness of cluster-based retrieval as a function of the exhaustivity of the uncontrolled subject descriptions. Results are compared to calculations for controlled descriptions based on Medical Subject Headings…

The development of structure in the expanding universe

NASA Technical Reports Server (NTRS)

Silk, J.; White, S. D.

1978-01-01

A model for clustering in an expanding universe is developed based on an application of the coagulation equation to the collision and aggregation of bound condensations. While the growth rate of clustering is determined by the rate at which density fluctuations reach the nonlinear regime and therefore depends on the initial fluctuation spectrum, the mass spectrum rapidly approaches a self-similar limiting form. This form is determined by the tidal processes which lead to the merging of condensations, and is not dependent on initial conditions.

One-way quantum computing in superconducting circuits

NASA Astrophysics Data System (ADS)

Albarrán-Arriagada, F.; Alvarado Barrios, G.; Sanz, M.; Romero, G.; Lamata, L.; Retamal, J. C.; Solano, E.

2018-03-01

We propose a method for the implementation of one-way quantum computing in superconducting circuits. Measurement-based quantum computing is a universal quantum computation paradigm in which an initial cluster state provides the quantum resource, while the iteration of sequential measurements and local rotations encodes the quantum algorithm. Up to now, technical constraints have limited a scalable approach to this quantum computing alternative. The initial cluster state can be generated with available controlled-phase gates, while the quantum algorithm makes use of high-fidelity readout and coherent feedforward. With current technology, we estimate that quantum algorithms with above 20 qubits may be implemented in the path toward quantum supremacy. Moreover, we propose an alternative initial state with properties of maximal persistence and maximal connectedness, reducing the required resources of one-way quantum computing protocols.

Quantum computational universality of the Cai-Miyake-Duer-Briegel two-dimensional quantum state from Affleck-Kennedy-Lieb-Tasaki quasichains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Tzu-Chieh; C. N. Yang Institute for Theoretical Physics, State University of New York at Stony Brook, Stony Brook, New York 11794-3840; Raussendorf, Robert

2011-10-15

Universal quantum computation can be achieved by simply performing single-qubit measurements on a highly entangled resource state, such as cluster states. Cai, Miyake, Duer, and Briegel recently constructed a ground state of a two-dimensional quantum magnet by combining multiple Affleck-Kennedy-Lieb-Tasaki quasichains of mixed spin-3/2 and spin-1/2 entities and by mapping pairs of neighboring spin-1/2 particles to individual spin-3/2 particles [Phys. Rev. A 82, 052309 (2010)]. They showed that this state enables universal quantum computation by single-spin measurements. Here, we give an alternative understanding of how this state gives rise to universal measurement-based quantum computation: by local operations, each quasichain canmore » be converted to a one-dimensional cluster state and entangling gates between two neighboring logical qubits can be implemented by single-spin measurements. We further argue that a two-dimensional cluster state can be distilled from the Cai-Miyake-Duer-Briegel state.« less

Whether the Autism Spectrum Quotient Consists of Two Different Subgroups? Cluster Analysis of the Autism Spectrum Quotient in General Population

ERIC Educational Resources Information Center

Kitazoe, Noriko; Fujita, Naofumi; Izumoto, Yuji; Terada, Shin-ichi; Hatakenaka, Yuhei

2017-01-01

The purpose of this study was to investigate whether the individuals in the general population with high scores on the Autism Spectrum Quotient constituted a single homogeneous group or not. A cohort of university students (n = 4901) was investigated by cluster analysis based on the original five subscales of the Autism Spectrum Quotient. Based on…

Do healthy and unhealthy behaviours cluster in New Zealand?

PubMed

Tobias, Martin; Jackson, Gary; Yeh, Li-Chia; Huang, Ken

2007-04-01

To describe the co-occurrence and clustering of healthy and unhealthy behaviours in New Zealand. Data were sourced from the 2002/03 New Zealand Health Survey. Behaviours selected for analysis were tobacco use, quantity and pattern of alcohol consumption, level of physical activity, and intake of fruit and vegetables. Clustering was defined as co-prevalence of behaviours greater than that expected based on the laws of probability. Co-occurrence was examined using multiple logistic regression modelling, while clustering was examined in a stratified analysis using age and (where appropriate) ethnic standardisation for confounding control. Approximately 29% of adults enjoyed a healthy lifestyle characterised by non-use of tobacco, non- or safe use of alcohol, sufficient physical activity and adequate fruit and vegetable intake. This is only slightly greater than the prevalence expected if all four behaviours were independently distributed through the population i.e. little clustering of healthy behaviours was found. By contrast, 1.5% of adults exhibited all four unhealthy behaviours and 13% exhibited any combination of three of the four unhealthy behaviours. Unhealthy behaviours were more clustered than healthy behaviours, yet Maori exhibited less clustering of unhealthy behaviours than other ethnic groups and no deprivation gradient was seen in clustering. The relative lack of clustering of healthy behaviours supports single issue universal health promotion strategies at the population level. Our results also support targeted interventions at the clinical level for the 15% with 'unhealthy lifestyles'. Our finding of only limited clustering of unhealthy behaviours among Maori and no deprivation gradient suggests that clustering does not contribute to the greater burden of disease experienced by these groups.

Perturbative universal state-selective correction for state-specific multi-reference coupled cluster methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brabec, Jiri; Banik, Subrata; Kowalski, Karol

2016-10-28

The implementation details of the universal state-selective (USS) multi-reference coupled cluster (MRCC) formalism with singles and doubles (USS(2)) are discussed on the example of several benchmark systems. We demonstrate that the USS(2) formalism is capable of improving accuracies of state specific multi-reference coupled-cluster (MRCC) methods based on the Brillouin-Wigner and Mukherjee’s sufficiency conditions. Additionally, it is shown that the USS(2) approach significantly alleviates problems associated with the lack of invariance of MRCC theories upon the rotation of active orbitals. We also discuss the perturbative USS(2) formulations that significantly reduce numerical overhead of the full USS(2) method.

Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling.

PubMed

Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

2015-09-18

This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols.

Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling

PubMed Central

Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

2015-01-01

This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols. PMID:26393608

Segmenting Student Markets with a Student Satisfaction and Priorities Survey.

ERIC Educational Resources Information Center

Borden, Victor M. H.

1995-01-01

A market segmentation analysis of 872 university students compared 2 hierarchical clustering procedures for deriving market segments: 1 using matching-type measures and an agglomerative clustering algorithm, and 1 using the chi-square based automatic interaction detection. Results and implications for planning, evaluating, and improving academic…

Principal Component Clustering Approach to Teaching Quality Discriminant Analysis

ERIC Educational Resources Information Center

Xian, Sidong; Xia, Haibo; Yin, Yubo; Zhai, Zhansheng; Shang, Yan

2016-01-01

Teaching quality is the lifeline of the higher education. Many universities have made some effective achievement about evaluating the teaching quality. In this paper, we establish the Students' evaluation of teaching (SET) discriminant analysis model and algorithm based on principal component clustering analysis. Additionally, we classify the SET…

UK Student Alcohol Consumption: A Cluster Analysis of Drinking Behaviour Typologies

ERIC Educational Resources Information Center

Craigs, Cheryl L.; Bewick, Bridgette M.; Gill, Jan; O'May, Fiona; Radley, Duncan

2012-01-01

Objective: To assess the extent to which university students are following UK Government advice regarding appropriate consumption of alcohol, and to investigate if students can be placed into distinct clusters based on their drinking behaviour. Design: A descriptive questionnaire study. Setting: One hundred and nineteen undergraduate students from…

Galaxy Cluster Smashes Distance Record

NASA Astrophysics Data System (ADS)

2009-10-01

he most distant galaxy cluster yet has been discovered by combining data from NASA's Chandra X-ray Observatory and optical and infrared telescopes. The cluster is located about 10.2 billion light years away, and is observed as it was when the Universe was only about a quarter of its present age. The galaxy cluster, known as JKCS041, beats the previous record holder by about a billion light years. Galaxy clusters are the largest gravitationally bound objects in the Universe. Finding such a large structure at this very early epoch can reveal important information about how the Universe evolved at this crucial stage. JKCS041 is found at the cusp of when scientists think galaxy clusters can exist in the early Universe based on how long it should take for them to assemble. Therefore, studying its characteristics - such as composition, mass, and temperature - will reveal more about how the Universe took shape. "This object is close to the distance limit expected for a galaxy cluster," said Stefano Andreon of the National Institute for Astrophysics (INAF) in Milan, Italy. "We don't think gravity can work fast enough to make galaxy clusters much earlier." Distant galaxy clusters are often detected first with optical and infrared observations that reveal their component galaxies dominated by old, red stars. JKCS041 was originally detected in 2006 in a survey from the United Kingdom Infrared Telescope (UKIRT). The distance to the cluster was then determined from optical and infrared observations from UKIRT, the Canada-France-Hawaii telescope in Hawaii and NASA's Spitzer Space Telescope. Infrared observations are important because the optical light from the galaxies at large distances is shifted into infrared wavelengths because of the expansion of the universe. The Chandra data were the final - but crucial - piece of evidence as they showed that JKCS041 was, indeed, a genuine galaxy cluster. The extended X-ray emission seen by Chandra shows that hot gas has been detected between the galaxies, as expected for a true galaxy cluster rather than one that has been caught in the act of forming. Also, without the X-ray observations, the possibility remained that this object could have been a blend of different groups of galaxies along the line of sight, or a filament, a long stream of galaxies and gas, viewed front on. The mass and temperature of the hot gas detected estimated from the Chandra observations rule out both of those alternatives. The extent and shape of the X-ray emission, along with the lack of a central radio source argue against the possibility that the X-ray emission is caused by scattering of cosmic microwave background light by particles emitting radio waves. It is not yet possible, with the detection of just one extremely distant galaxy cluster, to test cosmological models, but searches are underway to find other galaxy clusters at extreme distances. "This discovery is exciting because it is like finding a Tyrannosaurus Rex fossil that is much older than any other known," said co-author Ben Maughan, from the University of Bristol in the United Kingdom. "One fossil might just fit in with our understanding of dinosaurs, but if you found many more, you would have to start rethinking how dinosaurs evolved. The same is true for galaxy clusters and our understanding of cosmology." The previous record holder for a galaxy cluster was 9.2 billion light years away, XMMXCS J2215.9-1738, discovered by ESA's XMM-Newton in 2006. This broke the previous distance record by only about 0.1 billion light years, while JKCS041 surpasses XMMXCS J2215.9 by about ten times that. "What's exciting about this discovery is the astrophysics that can be done with detailed follow-up studies," said Andreon. Among the questions scientists hope to address by further studying JKCS041 are: What is the build-up of elements (such as iron) like in such a young object? Are there signs that the cluster is still forming? Do the temperature and X-ray brightness of such a distant cluster relate to its mass in the same simple way as they do for nearby clusters? The paper describing the results on JKCS041 from Andreon and his colleagues will appear in an upcoming issue of the journal Astronomy and Astrophysics. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington, DC. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Integrating participatory community mobilization processes to improve dengue prevention: an eco-bio-social scaling up of local success in Machala, Ecuador

PubMed Central

Mitchell-Foster, Kendra; Ayala, Efraín Beltrán; Breilh, Jaime; Spiegel, Jerry; Wilches, Ana Arichabala; Leon, Tania Ordóñez; Delgado, Jefferson Adrian

2015-01-01

Background This project investigates the effectiveness and feasibility of scaling-up an eco-bio-social approach for implementing an integrated community-based approach for dengue prevention in comparison with existing insecticide-based and emerging biolarvicide-based programs in an endemic setting in Machala, Ecuador. Methods An integrated intervention strategy (IIS) for dengue prevention (an elementary school-based dengue education program, and clean patio and safe container program) was implemented in 10 intervention clusters from November 2012 to November 2013 using a randomized controlled cluster trial design (20 clusters: 10 intervention, 10 control; 100 households per cluster with 1986 total households). Current existing dengue prevention programs served as the control treatment in comparison clusters. Pupa per person index (PPI) is used as the main outcome measure. Particular attention was paid to social mobilization and empowerment with IIS. Results Overall, IIS was successful in reducing PPI levels in intervention communities versus control clusters, with intervention clusters in the six paired clusters that followed the study design experiencing a greater reduction of PPI compared to controls (2.2 OR, 95% CI: 1.2 to 4.7). Analysis of individual cases demonstrates that consideration for contexualizing programs and strategies to local neighborhoods can be very effective in reducing PPI for dengue transmission risk reduction. Conclusions In the rapidly evolving political climate for dengue control in Ecuador, integration of successful social mobilization and empowerment strategies with existing and emerging biolarvicide-based government dengue prevention and control programs is promising in reducing PPI and dengue transmission risk in southern coastal communities like Machala. However, more profound analysis of social determination of health is called for to assess sustainability prospects. PMID:25604763

Enacs Survey of Southern Galaxies Indicates Open Universe

NASA Astrophysics Data System (ADS)

1996-02-01

New Light on Rich Clusters of Galaxies and their Formation History In the context of a comprehensive Key-Programme , carried out with telescopes at the ESO La Silla Observatory, a team of European astronomers [1]. has recently obtained radial velocities for more than 5600 galaxies in about 100 rich clusters of galaxies. With this programme the amount of information about the motions of galaxies (the kinematical data) in such clusters has almost been doubled. This has allowed the team to study the distribution of the cluster masses, and also the dynamical state of clusters in new and interesting ways. An important result of this programme is that the derived masses of the investigated clusters of galaxies indicate that the mean density of the Universe is insufficient to halt the current expansion; we may therefore be living in an open Universe that will expand forever. Clusters of galaxies as tracers of large-scale structure About 40 years ago, American astronomer George Abell, working at the Palomar Observatory in California, was the first to perform a systematic study of rich clusters of galaxies , that is clusters with particularly many member galaxies located within a relatively restricted region in the sky. He identified several thousands of such clusters, and he numbered and described them; they are now known to astronomers as `Abell clusters'. More than twenty years earlier, Swiss-American astronomer Fritz Zwicky, using the famous 100-inch Mount Wilson telescope above Los Angeles, concluded that the total mass of a rich cluster of galaxies is probably much larger than the combined mass of the individual galaxies we can observe in it. This phenomenon is now known as the `Missing Dark Matter' , and many attempts have since been made to understand its true nature. Although the existence of this Dark Matter is generally accepted, it has been very difficult to prove its existence in a direct way. Rich clusters have several components: in addition to several hundreds, in some cases even thousands of galaxies (each with many billions of stars and much interstellar matter), they also contain hot gas (with a temperature of several million degrees) which is best visible in X-rays, as well as the invisible dark matter just mentioned. In fact, these clusters are the largest and most massive objects that are known today, and a detailed study of their properties can therefore provide insight into the way in which large-scale structures in the Universe have formed. This unique information is encoded into the distribution of the clusters' total masses, of their physical shapes, and not the least in the way they are distributed in space. The need for a `complete' cluster sample Several of these fundamental questions can be studied by observing a few, or at the most several tens of well-chosen clusters. However, if the goal is to discriminate between the various proposed theories of formation of their spatial distribution and thus the Universe's large-scale structure, it is essential that uniform data is collected for a sample of clusters that is complete in a statistical sense. Only then will it be possible to determine reliably the distribution of cluster masses and shapes, etc. For such comprehensive investigations, `complete' samples of clusters (that is, brighter than a certain magnitude and located within a given area in the sky) can be compiled either by means of catalogues like the one published by Abell and his collaborators and based on the distribution of optically selected galaxies, or from large-scale surveys of X-ray sources. However, in both cases, it is of paramount importance to verify the physical reality of the presumed clusters. Sometimes several galaxies are seen in nearly the same direction and therefore appear to form a cluster, but it later turns out that they are at very different distances and do not form a physical entity. This control must be performed through spectroscopic observations of the galaxies in the candidate clusters. Such observations are crucial, as they not only prove the existence of a cluster, but also determine its distance and provide information about the motion of the individual galaxies within the cluster. The ESO Nearby Abell Cluster Survey (ENACS) Until recently, there existed no large cluster sample with extensive and uniform data on the motions of the individual galaxies. But now, in the context of an ESO Key-Programme known as the ESO Nearby Abell Cluster Survey or ENACS , the team of European astronomers has collected spectroscopic and photometric data for a substantial sample of more than one-hundred, rich and relatively nearby southern clusters from the Abell catalogue [2]. The extensive observations were carried out with the OPTOPUS multi-fibre spectrograph attached to the ESO 3.6-metre telescope at the La Silla Observatory, during 35 nights in the period from September 1989 to October 1993. With this very efficient spectrograph, the spectra of about 50 galaxies could be recorded simultaneously, dramatically reducing the necessary observing time. In total, the programme has yielded reliable radial velocities for more than 5600 galaxies in the direction of about 100 rich clusters. The velocities were derived from a comparison of the observed wavelengths of absorption and emission lines with their rest wavelengths (the galaxy `redshifts'). Assuming a particular value of the `Hubble constant' (the proportionality factor between the velocity of a galaxy and its distance, due to the general expansion of the Universe), the distances of the galaxies can then be derived directly from the measured velocities. The new observations approximately double the amount of data available for rich clusters of galaxies. In combination with earlier data, the ENACS has produced a `complete' sample of 128 rich Abell clusters in a region centered near the south galactic pole (the direction which is perpendicular to the main plane of the Milky Way galaxy), and comprising about one-fifth of the entire sky. The sample extends out to a cluster distance of almost 1,000 million light-years (300 Mpc) The space density of the 128 clusters is constant within the investigated volume, so that this sample is well suited to study, among others, the distribution of cluster masses. For a representative subset of 80 clusters, accurate information on the internal motions of galaxies in the clusters is available. Most nearby and rich Abell clusters are real In their pioneering work, Abell and his collaborators identified the clusters from visual inspection of photographic plates obtained with the Palomar telescopes [3]. Some concern has frequently been expressed that an important fraction of the rich Abell clusters may not be real, but rather the result of chance superpositions in the sky of several smaller groups of galaxies. However, the data of the ENACS now prove conclusively that 90 percent of the rich, nearby Abell clusters are real: i.e. many of the galaxies observed in each of these clusters are indeed at the same distance and they form a physical entity. Nevertheless, about one-quarter of the galaxies in the ENACS do not belong to the main clusters and reside in much smaller galaxy groups or are located in the vast space in between. This can be clearly seen in the distribution of the radial velocities in the direction of each of the clusters, shown in the diagramme (click here to get the [GIF,35k] or [Postscript,544k] version and the caption ) attached to this Press Release. When studying this distribution, it must be kept in mind, that the velocities of the galaxies in the clusters contain two components. The first is due to the general expansion of the Universe and depends only on the distance of the cluster; it is therefore the same for all galaxies in the cluster. The other reflects the individual motions of the galaxies within the cluster. Cluster masses and the mean density of the Universe The motions of the galaxies within a cluster makes it possible to estimate the total mass of the cluster: the greater the mass, the faster the motions must be in order to prevent the cluster from collapsing [4]. Using the data for the full sample of 128 clusters, the distribution of cluster masses has been derived. This distribution has been compared with predictions based on several models for the formation of large-scale structures in the Universe. A very important result of the current work is that the observations do not support scenarios which are based on the assumption that the mean density of the Universe is equal to the `critical' value, i.e. the one which would correspond to a so-called `flat' Universe. The observed cluster masses are systematically smaller than those predicted in such models. Instead, the observed distribution of cluster masses seems to indicate that the mean density of the Universe is probably only a fairly small fraction of the critical value. This points to the Universe being `open' and ever-expanding. Cluster formation may still be going on The galaxies observed during the ENACS programme may be divided into two groups on the basis of their optical spectra, those that show clear emission lines and those that do not. The former are almost all late-type galaxies, that is spiral galaxies with ionized gas in their disks which gives rise to the emission lines. It appears that both the distribution within the cluster, as well as the velocities, of the galaxies with emission lines are significantly different from those of the galaxies without emission lines. It seems that the emission-line galaxies have a tendency to avoid the central regions of their clusters, and their average radial velocities are about 20 percent larger than those of the non-emission galaxies. A plausible interpretation of these results is that a large part of the emission-line galaxies have not yet `mixed' with the other galaxies, and that they are approaching the central regions of their respective clusters for the first time. This may imply that the formation of at least a good fraction of the nearby, rich clusters is still going on. If the mean density of the Universe is indeed much smaller than the critical density, as indicated by the cluster masses determined during this survey, then this is a quite unexpected result. One explanation may be that many clusters have only started to form fairly recently. Notes: [1] The team is headed by Peter Katgert (Leiden Observatory, The Netherlands) and Alain Mazure (Laboratoire d'Astronomie Spatiale, Marseille, France); other members are Andrea Biviano and Roland den Hartog (Leiden Observatory, The Netherlands), Pierre Dubath (Observatoire de Geneve, Switzerland), Eric Escalera (SISSA, Trieste, Italy), Paola Focardi (Bologna University, Italy), Daniel Gerbal (Institut d'Astrophysique, Paris, France), Guilano Giuricin (SISSA, Trieste, Italy), Bernard Jones (Theoretical Astrophysics Centre, Copenhagen, Denmark), Olivier Le Fevre (Meudon Observatory, Paris, France), Mariano Moles and Jaime Perea (Astrophysics Institute of Andalucia, Granada, Spain), and George Rhee (University of Nevada, Las Vegas, U.S.A.). [2] The detailed results will soon be published in two comprehensive articles to appear in the European journal Astronomy & Astrophysics. [3] This Press Release is accompanied by ESO Press Photo 07/96, (click here to get the image [GIF,45k] and caption ) showing one of the rich clusters, as observed with the ESO 1-metre Schmidt telescope. [4] The masses of the planets in the solar system are determined in a similar way from the motions of their moons. The faster the moon moves around the planet at a given distance, the heavier is the planet.

Cosmological constraints from strong gravitational lensing in clusters of galaxies.

PubMed

Jullo, Eric; Natarajan, Priyamvada; Kneib, Jean-Paul; D'Aloisio, Anson; Limousin, Marceau; Richard, Johan; Schimd, Carlo

2010-08-20

Current efforts in observational cosmology are focused on characterizing the mass-energy content of the universe. We present results from a geometric test based on strong lensing in galaxy clusters. Based on Hubble Space Telescope images and extensive ground-based spectroscopic follow-up of the massive galaxy cluster Abell 1689, we used a parametric model to simultaneously constrain the cluster mass distribution and dark energy equation of state. Combining our cosmological constraints with those from x-ray clusters and the Wilkinson Microwave Anisotropy Probe 5-year data gives Omega(m) = 0.25 +/- 0.05 and w(x) = -0.97 +/- 0.07, which are consistent with results from other methods. Inclusion of our method with all other available techniques brings down the current 2sigma contours on the dark energy equation-of-state parameter w(x) by approximately 30%.

US Japan Workshop. Hybrid 2000 Conference Held in Ithaca, New York on May 7-12, 2000

DTIC Science & Technology

2001-05-31

Illinois University) 10:30-10:45 BREAK 10:45-11:30 "Nano-Objects With Controlled Shape, Size and Composition From Block Copolymer-Ceramic Hybrid...Alkoxysilanes", Yoshiyuki Sugahara (Waseda University) 12:30 depart for Corning Glass Museum Tour Box lunches provided by Ramada Inn 5:30PM drop off at MV...well-controlled. If the size of the clusters is too large, the hybrids would be brittle as Si02 gels and glasses are. Thus, the control over the

Effectiveness of a universal internet-based prevention program for ecstasy and new psychoactive substances: a cluster randomized controlled trial.

PubMed

Champion, Katrina E; Newton, Nicola C; Stapinski, Lexine A; Teesson, Maree

2016-08-01

To evaluate the effectiveness of an online school-based prevention program for ecstasy (MDMA) and new psychoactive substances (NPS). Cluster randomized controlled trial with two groups (intervention and control). Eleven secondary schools in Australia. A total of 1126 students (mean age: 14.9 years). The internet-based Climate Schools: Ecstasy and Emerging Drugs module uses cartoon storylines to convey information about harmful drug use. It was delivered once weekly, during a 4-week period, during health education classes. Control schools received health education as usual. Primary outcomes were self-reported intentions to use ecstasy and NPS at 12 months. Secondary outcomes were ecstasy and NPS knowledge and life-time use of ecstasy and NPS. Surveys were administered at baseline, post-intervention and 6 and 12 month post-baseline. At 12 months, the proportion of students likely to use NPS was significantly greater in the control group (1.8%) than the intervention group [0.5%; odds ratio (OR) = 10.17, 95% confidence interval (CI) = 1.31-78.91]. However, students' intentions to use ecstasy did not differ significantly between groups (control = 2.1%, intervention = 1.6%; OR = 5.91, 95% CI = 1.01-34.73). There was a significant group difference in the change from baseline to post-test for NPS knowledge (β = -0.42, 95% CI = -0.62 to -0.21, Cohen's d = 0.77), with controls [mean = 2.78, standard deviation (SD = 1.48] scoring lower than intervention students (mean = 3.85, SD = 1.49). There was also evidence of a significant group difference in ecstasy knowledge at post-test (control: mean = 9.57, SD = 3.31; intervention: mean = 11.57, SD = 3.61; β = -0.54, 95% CI = -0.97 to -0.12, P = 0.01, d = 0.73). The Climate Schools: Ecstasy and Emerging Drugs module, a universal online school-based prevention program, appeared to reduce students' intentions to use new psychoactive substances and increased knowledge about ecstasy and new psychoactive substances in the short term. © 2016 Society for the Study of Addiction.

Distant clusters of galaxies in the 2XMM/SDSS footprint: follow-up observations with the LBT

NASA Astrophysics Data System (ADS)

Rabitz, A.; Lamer, G.; Schwope, A.; Takey, A.

2017-11-01

Context. Galaxy clusters at high redshift are important to test cosmological models and models for the growth of structure. They are difficult to find in wide-angle optical surveys, however, leaving dedicated follow-up of X-ray selected candidates as one promising identification route. Aims: We aim to increase the number of galaxy clusters beyond the SDSS-limit, z 0.75. Methods: We compiled a list of extended X-ray sources from the 2XMMp catalogue within the footprint of the Sloan Digital Sky Survey. Fields without optical counterpart were selected for further investigation. Deep optical imaging and follow-up spectroscopy were obtained with the Large Binocular Telescope, Arizona (LBT), of those candidates not known to the literature. Results: From initially 19 candidates, selected by visually screening X-ray images of 478 XMM-Newton observations and the corresponding SDSS images, 6 clusters were found in the literature. Imaging data through r,z filters were obtained for the remaining candidates, and 7 were chosen for multi-object (MOS) spectroscopy. Spectroscopic redshifts, optical magnitudes, and X-ray parameters (flux, temperature, and luminosity) are presented for the clusters with spectroscopic redshifts. The distant clusters studied here constitute one additional redshift bin for studies of the LX-T relation, which does not seem to evolve from high to low redshifts. Conclusions: The selection method of distant galaxy clusters presented here was highly successful. It is based solely on archival optical (SDSS) and X-ray (XMM-Newton) data. Out of 19 selected candidates, 6 of the 7 candidates selected for spectroscopic follow-up were verified as distant clusters, a further candidate is most likely a group of galaxies at z 1.21. Out of the remaining 12 candidates, 6 were known previously as galaxy clusters, one object is a likely X-ray emission from an AGN radio jet, and for 5 we see no clear evidence for them to be high-redshift galaxy clusters. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: the University of Arizona on behalf of the Arizona Board of Regents; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, The Leibniz Institute for Astrophysics Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota and University of Virginia - http://www.lbto.org/for-investigators.htmlThe catalogue, similar to Table A.1, is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A56

ClusterControl: a web interface for distributing and monitoring bioinformatics applications on a Linux cluster.

PubMed

Stocker, Gernot; Rieder, Dietmar; Trajanoski, Zlatko

2004-03-22

ClusterControl is a web interface to simplify distributing and monitoring bioinformatics applications on Linux cluster systems. We have developed a modular concept that enables integration of command line oriented program into the application framework of ClusterControl. The systems facilitate integration of different applications accessed through one interface and executed on a distributed cluster system. The package is based on freely available technologies like Apache as web server, PHP as server-side scripting language and OpenPBS as queuing system and is available free of charge for academic and non-profit institutions. http://genome.tugraz.at/Software/ClusterControl

An exploratory cluster randomised trial of a university halls of residence based social norms intervention in Wales, UK

PubMed Central

2012-01-01

Background Excessive alcohol consumption amongst university students has received increasing attention. A social norms approach to reducing drinking behaviours has met with some success in the USA. Such an approach is based on the assumption that student's perceptions of the norms of their peers are highly influential, but that these perceptions are often incorrect. Social norms interventions therefore aim to correct these inaccurate perceptions, and in turn, to change behaviours. However, UK studies are scarce and it is increasingly recognised that social norm interventions need to be supported by socio ecological approaches that address the wider determinants of behaviour. Objectives To describe the research design for an exploratory trial examining the acceptability, hypothesised process of change and implementation of a social norm marketing campaign designed to correct misperceptions of normative alcohol use and reduce levels of misuse, implemented alongside a university wide alcohol harm reduction toolkit. It also assesses the feasibility of a potential large scale effectiveness trial by providing key trial design parameters including randomisation, recruitment and retention, contamination, data collection methods, outcome measures and intracluster correlations. Methods/design The study adopts an exploratory cluster randomised controlled trial design with halls of residence as the unit of allocation, and a nested mixed methods process evaluation. Four Welsh (UK) universities participated in the study, with residence hall managers consenting to implementation of the trial in 50 university owned campus based halls of residence. Consenting halls were randomised to either a phased multi channel social norm marketing campaign addressing normative discrepancies (n = 25 intervention) or normal practice (n = 25 control). The primary outcome is alcohol consumption (units per week) measured using the Daily Drinking Questionnaire. Secondary outcomes assess frequency of alcohol consumption, higher risk drinking, alcohol related problems and change in perceptions of alcohol-related descriptive and injunctive norms. Data will be collected for all 50 halls at 4 months follow up through a cross-sectional on line and postal survey of approximately 4000 first year students. The process evaluation will explore the acceptability and implementation of the social norms intervention and toolkit and hypothesised process of change including awareness, receptivity and normative changes. Discussion Exploratory trials such as this are essential to inform future definitive trials by providing crucial methodological parameters and guidance on designing and implementing optimum interventions. Trial registration number ISRCTN: ISRCTN48556384 PMID:22414293

Constraints on the Energy Content of the Universe from a Combination of Galaxy Cluster Observables

NASA Technical Reports Server (NTRS)

Molnar, Sandor M.; Haiman, Zoltan; Birkinshaw, Mark; Mushotzky, Richard F.

2003-01-01

We demonstrate that constraints on cosmological parameters from the distribution of clusters as a function of redshift (dN/dz) are complementary to accurate angular diameter distance (D(sub A)) measurements to clusters, and their combination significantly tightens constraints on the energy density content of the Universe. The number counts can be obtained from X-ray and/or SZ (Sunyaev-Ze'dovich effect) surveys, and the angular diameter distances can be determined from deep observations of the intra-cluster gas using their thermal bremsstrahlung X-ray emission and the SZ effect. We combine constraints from simulated cluster number counts expected from a 12 deg(sup 2) SZ cluster survey and constraints from simulated angular diameter distance measurements based on the X-ray/SZ method assuming a statistical accuracy of 10% in the angular diameter distance determination of 100 clusters with redshifts less than 1.5. We find that Omega(sub m), can be determined within about 25%, Omega(sub lambda) within 20% and w within 16%. We show that combined dN/dz+(sub lambda) constraints can be used to constrain the different energy densities in the Universe even in the presence of a few percent redshift dependent systematic error in D(sub lambda). We also address the question of how best to select clusters of galaxies for accurate diameter distance determinations. We show that the joint dN/dz+ D(lambda) constraints on cosmological parameters for a fixed target accuracy in the energy density parameters are optimized by selecting clusters with redshift upper cut-offs in the range 0.55 approx. less than 1. Subject headings: cosmological parameters - cosmology: theory - galaxies:clusters: general

Nonlinear management of the angular momentum of soliton clusters: Theory and experiment

NASA Astrophysics Data System (ADS)

Fratalocchi, Andrea; Piccardi, Armando; Peccianti, Marco; Assanto, Gaetano

2007-06-01

We demonstrate, both theoretically and experimentally, how to acquire nonlinear control over the angular momentum of a cluster of solitary waves. Our results, stemming from a universal theoretical model, show that the angular momentum can be adjusted by acting on the global energy input in the system. The phenomenon is experimentally ascertained in nematic liquid crystals by observing a power-dependent rotation of a two-soliton ensemble.

Data Mining of University Philanthropic Giving: Cluster-Discriminant Analysis and Pareto Effects

ERIC Educational Resources Information Center

Le Blanc, Louis A.; Rucks, Conway T.

2009-01-01

A large sample of 33,000 university alumni records were cluster-analyzed to generate six groups relatively unique in their respective attribute values. The attributes used to cluster the former students included average gift to the university's foundation and to the alumni association for the same institution. Cluster detection is useful in this…

Chandra Catches "Piranha" Black Holes

NASA Astrophysics Data System (ADS)

2007-07-01

Supermassive black holes have been discovered to grow more rapidly in young galaxy clusters, according to new results from NASA's Chandra X-ray Observatory. These "fast-track" supermassive black holes can have a big influence on the galaxies and clusters that they live in. Using Chandra, scientists surveyed a sample of clusters and counted the fraction of galaxies with rapidly growing supermassive black holes, known as active galactic nuclei (or AGN). The data show, for the first time, that younger, more distant galaxy clusters contained far more AGN than older, nearby ones. Galaxy clusters are some of the largest structures in the Universe, consisting of many individual galaxies, a few of which contain AGN. Earlier in the history of the universe, these galaxies contained a lot more gas for star formation and black hole growth than galaxies in clusters do today. This fuel allows the young cluster black holes to grow much more rapidly than their counterparts in nearby clusters. Illustration of Active Galactic Nucleus Illustration of Active Galactic Nucleus "The black holes in these early clusters are like piranha in a very well-fed aquarium," said Jason Eastman of Ohio State University (OSU) and first author of this study. "It's not that they beat out each other for food, rather there was so much that all of the piranha were able to really thrive and grow quickly." The team used Chandra to determine the fraction of AGN in four different galaxy clusters at large distances, when the Universe was about 58% of its current age. Then they compared this value to the fraction found in more nearby clusters, those about 82% of the Universe's current age. The result was the more distant clusters contained about 20 times more AGN than the less distant sample. AGN outside clusters are also more common when the Universe is younger, but only by factors of two or three over the same age span. "It's been predicted that there would be fast-track black holes in clusters, but we never had good evidence until now," said co-author Paul Martini, also of OSU. "This can help solve a couple of mysteries about galaxy clusters." One mystery is why there are so many blue, star-forming galaxies in young, distant clusters and fewer in nearby, older clusters. AGN are believed to expel or destroy cool gas in their host galaxy through powerful eruptions from the black hole. This may stifle star formation and the blue, massive stars will then gradually die off, leaving behind only the old, redder stars. This process takes about a billion years or more to take place, so a dearth of star-forming galaxies is only noticeable for older clusters. The process that sets the temperature of the hot gas in clusters when they form is also an open question. These new results suggest that even more AGN may have been present when most clusters were forming about ten billion years ago. Early heating of a cluster by large numbers of AGN can have a significant, long-lasting effect on the structure of a cluster by "puffing up" the gas. "In a few nearby clusters we've seen evidence for huge eruptions generated by supermassive black holes. But this is sedate compared to what might be going on in younger clusters," said Eastman. These results appeared in the July 20th issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

A Cluster-Based Dual-Adaptive Topology Control Approach in Wireless Sensor Networks.

PubMed

Gui, Jinsong; Zhou, Kai; Xiong, Naixue

2016-09-25

Multi-Input Multi-Output (MIMO) can improve wireless network performance. Sensors are usually single-antenna devices due to the high hardware complexity and cost, so several sensors are used to form virtual MIMO array, which is a desirable approach to efficiently take advantage of MIMO gains. Also, in large Wireless Sensor Networks (WSNs), clustering can improve the network scalability, which is an effective topology control approach. The existing virtual MIMO-based clustering schemes do not either fully explore the benefits of MIMO or adaptively determine the clustering ranges. Also, clustering mechanism needs to be further improved to enhance the cluster structure life. In this paper, we propose an improved clustering scheme for virtual MIMO-based topology construction (ICV-MIMO), which can determine adaptively not only the inter-cluster transmission modes but also the clustering ranges. Through the rational division of cluster head function and the optimization of cluster head selection criteria and information exchange process, the ICV-MIMO scheme effectively reduces the network energy consumption and improves the lifetime of the cluster structure when compared with the existing typical virtual MIMO-based scheme. Moreover, the message overhead and time complexity are still in the same order of magnitude.

A Cluster-Based Dual-Adaptive Topology Control Approach in Wireless Sensor Networks

PubMed Central

Gui, Jinsong; Zhou, Kai; Xiong, Naixue

2016-01-01

Multi-Input Multi-Output (MIMO) can improve wireless network performance. Sensors are usually single-antenna devices due to the high hardware complexity and cost, so several sensors are used to form virtual MIMO array, which is a desirable approach to efficiently take advantage of MIMO gains. Also, in large Wireless Sensor Networks (WSNs), clustering can improve the network scalability, which is an effective topology control approach. The existing virtual MIMO-based clustering schemes do not either fully explore the benefits of MIMO or adaptively determine the clustering ranges. Also, clustering mechanism needs to be further improved to enhance the cluster structure life. In this paper, we propose an improved clustering scheme for virtual MIMO-based topology construction (ICV-MIMO), which can determine adaptively not only the inter-cluster transmission modes but also the clustering ranges. Through the rational division of cluster head function and the optimization of cluster head selection criteria and information exchange process, the ICV-MIMO scheme effectively reduces the network energy consumption and improves the lifetime of the cluster structure when compared with the existing typical virtual MIMO-based scheme. Moreover, the message overhead and time complexity are still in the same order of magnitude. PMID:27681731

Chandra Finds Most Distant X-ray Galaxy Cluster

NASA Astrophysics Data System (ADS)

2001-02-01

The most distant X-ray cluster of galaxies yet has been found by astronomers using NASA’s Chandra X-ray Observatory. Approximately 10 billion light years from Earth, the cluster 3C294 is 40 percent farther than the next most distant X-ray galaxy cluster. The existence of such a distant galaxy cluster is important for understanding how the universe evolved. "Distant objects like 3C294 provide snapshots to how these galaxy clusters looked billions of years ago," said Andrew Fabian of the Institute of Astronomy, Cambridge, England and lead author of the paper accepted for publication in the Monthly Notices of Britain’s Royal Astronomical Society. "These latest results help us better understand what the universe was like when it was only 20 percent of its current age." Chandra’s image reveals an hourglass-shaped region of X-ray emission centered on the previously known central radio source. This X-ray emission extends outward from the central galaxy for at least 300,000 light years and shows that the known radio source is in the central galaxy of a massive cluster. Scientists have long suspected that distant radio-emitting galaxies like 3C294 are part of larger groups of galaxies known as "clusters." However, radio data provides astronomers with only a partial picture of these distant objects. Confirmation of the existence of clusters at great distances - and, hence, at early stages of the universe - requires information from other wavelengths. Optical observations can be used to pinpoint individual galaxies, but X-ray data are needed to detect the hot gas that fills the space within the cluster. "Galaxy clusters are the largest gravitationally bound structures in the universe," said Fabian. "We do not expect to find many massive objects, such as the 3C294 cluster, in early times because structure is thought to grow from small scales to large scales." The vast clouds of hot gas that envelope galaxies in clusters are thought to be heated by collapse toward the center of the cluster. Until Chandra, X-ray telescopes have not had the needed sensitivity to identify and measure hot gas clouds in distant clusters. Carolin Crawford, Stefano Ettori and Jeremy Sanders of the Institute of Astronomy were also members of the team that observed 3C294 for 5.4 hours on October 29, 2000 with the Advanced CCD Imaging Spectrometer (ACIS). The ACIS X-ray camera was developed for NASA by Pennsylvania State University and Massachusetts Institute of Technology. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program for the Office of Space Science in Washington, DC. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov

The Most Distant Mature Galaxy Cluster - Young, but surprisingly grown-up

NASA Astrophysics Data System (ADS)

2011-03-01

Astronomers have used an armada of telescopes on the ground and in space, including the Very Large Telescope at ESO's Paranal Observatory in Chile to discover and measure the distance to the most remote mature cluster of galaxies yet found. Although this cluster is seen when the Universe was less than one quarter of its current age it looks surprisingly similar to galaxy clusters in the current Universe. "We have measured the distance to the most distant mature cluster of galaxies ever found", says the lead author of the study in which the observations from ESO's VLT have been used, Raphael Gobat (CEA, Paris). "The surprising thing is that when we look closely at this galaxy cluster it doesn't look young - many of the galaxies have settled down and don't resemble the usual star-forming galaxies seen in the early Universe." Clusters of galaxies are the largest structures in the Universe that are held together by gravity. Astronomers expect these clusters to grow through time and hence that massive clusters would be rare in the early Universe. Although even more distant clusters have been seen, they appear to be young clusters in the process of formation and are not settled mature systems. The international team of astronomers used the powerful VIMOS and FORS2 instruments on ESO's Very Large Telescope (VLT) to measure the distances to some of the blobs in a curious patch of very faint red objects first observed with the Spitzer space telescope. This grouping, named CL J1449+0856 [1], had all the hallmarks of being a very remote cluster of galaxies [2]. The results showed that we are indeed seeing a galaxy cluster as it was when the Universe was about three billion years old - less than one quarter of its current age [3]. Once the team knew the distance to this very rare object they looked carefully at the component galaxies using both the NASA/ESA Hubble Space Telescope and ground-based telescopes, including the VLT. They found evidence suggesting that most of the galaxies in the cluster were not forming stars, but were composed of stars that were already about one billion years old. This makes the cluster a mature object, similar in mass to the Virgo Cluster, the nearest rich galaxy cluster to the Milky Way. Further evidence that this is a mature cluster comes from observations of X-rays coming from CL J1449+0856 made with ESA's XMM-Newton space observatory. The cluster is giving off X-rays that must be coming from a very hot cloud of tenuous gas filling the space between the galaxies and concentrated towards the centre of the cluster. This is another sign of a mature galaxy cluster, held firmly together by its own gravity, as very young clusters have not had time to trap hot gas in this way. As Gobat concludes: "These new results support the idea that mature clusters existed when the Universe was less than one quarter of its current age. Such clusters are expected to be very rare according to current theory, and we have been very lucky to spot one. But if further observations find many more then this may mean that our understanding of the early Universe needs to be revised." Notes [1] The strange name refers to the object's position in the sky. [2] The galaxies appear red in the picture partly because they are thought to be mainly composed of cool, red stars. In addition the expansion of the Universe since the light left these remote systems has increased the wavelength of the light further so that it is mostly seen as infrared radiation when it gets to Earth. [3] The astronomers measured the distance to the cluster by splitting the light up into its component colours in a spectrograph. They then compared this spectrum with one of a similar object in the nearby Universe. This allowed them to measure the redshift of the remote galaxies - how much the Universe has expanded since the light left the galaxies. The redshift was found to be 2.07, which means that the cluster is seen about three billion years after the Big Bang. More information This research was presented in a paper, "A mature cluster with X-ray emission at z = 2.07", by R. Gobat et al., published in the journal Astronomy & Astrophysics. The team is composed of R. Gobat (Laboratoire AIM-Paris-Saclay, France), E. Daddi (AIM-Paris), M. Onodera (ETH Zürich, Switzerland), A. Finoguenov (Max-Planck-Institut für extraterrestrische Physik [MPE], Garching, Germany), A. Renzini (INAF-Osservatorio Astronomico di Padova), N. Arimoto (National Astronomical Observatory of Japan), R. Bouwens (Lick Observatory, Santa Cruz, USA), M. Brusa (MPE), R.-R. Chary (California Institute of Technology, USA), A. Cimatti (Università di Bologna, Italy), M. Dickinson (NOAO, Tucson, USA), X. Kong (University of Science and Technology of China), and M.Mignoli (INAF - Osservatorio Astronomico di Bologna, Italy). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

The Heterogeneity of the Academic Profession: The Effect of Occupational Variables on University Scientists' Participation in Research Commercialization

ERIC Educational Resources Information Center

Novotny, Adam

2017-01-01

Do academics who commercialize their inventions have a different professional character than those who do not? The author conducted a nationwide survey in Hungary including 1,562 academics of hard sciences from 14 universities. According to the cluster analysis based on their participation in research commercialization (RC), university scholars…

Quantum computational universality of the Cai-Miyake-Dür-Briegel two-dimensional quantum state from Affleck-Kennedy-Lieb-Tasaki quasichains

NASA Astrophysics Data System (ADS)

Wei, Tzu-Chieh; Raussendorf, Robert; Kwek, Leong Chuan

2011-10-01

Universal quantum computation can be achieved by simply performing single-qubit measurements on a highly entangled resource state, such as cluster states. Cai, Miyake, Dür, and Briegel recently constructed a ground state of a two-dimensional quantum magnet by combining multiple Affleck-Kennedy-Lieb-Tasaki quasichains of mixed spin-3/2 and spin-1/2 entities and by mapping pairs of neighboring spin-1/2 particles to individual spin-3/2 particles [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.82.052309 82, 052309 (2010)]. They showed that this state enables universal quantum computation by single-spin measurements. Here, we give an alternative understanding of how this state gives rise to universal measurement-based quantum computation: by local operations, each quasichain can be converted to a one-dimensional cluster state and entangling gates between two neighboring logical qubits can be implemented by single-spin measurements. We further argue that a two-dimensional cluster state can be distilled from the Cai-Miyake-Dür-Briegel state.

Mississippi State University Center for Air Sea Technology. FY93 and FY 94 Research Program in Navy Ocean Modeling and Prediction

DTIC Science & Technology

1994-09-30

relational versus object oriented DBMS, knowledge discovery, data models, rnetadata, data filtering, clustering techniques, and synthetic data. A secondary...The first was the investigation of Al/ES Lapplications (knowledge discovery, data mining, and clustering ). Here CAST collabo.rated with Dr. Fred Petry...knowledge discovery system based on clustering techniques; implemented an on-line data browser to the DBMS; completed preliminary efforts to apply object

Chandra Finds Ghosts Of Eruption In Galaxy Cluster

NASA Astrophysics Data System (ADS)

2002-01-01

"Ghostly" relics of an ancient eruption that tore through a cluster of galaxies were recently uncovered by NASA's Chandra X-ray Observatory. The discovery implies that galaxy clusters are the sites of enormously energetic and recurring explosions, and may provide an explanation why galaxy clusters behave like giant cosmic magnets. "Chandra's image revealed vast regions in the galaxy cluster Abell 2597 that contain almost no X-ray or radio emission. We call them ghost cavities," said Brian McNamara of Ohio University in Athens today during a press conference at the American Astronomical Society meeting in Washington. "They appear to be remnants of an old explosion where the radio emission has faded away over millions of years." The ghost cavities were likely created by extremely powerful explosions, due to material falling toward a black hole millions of times more massive than the Sun. As the matter swirled around the black hole, located in a galaxy near the center of the cluster, it generated enormous electromagnetic fields that expelled material from the vicinity of the black hole at high speeds. This explosive activity in Abell 2597 created jets of highly energetic particles that cleared out voids in the hot gas. Because they are lighter than the surrounding material, the cavities will eventually push their way to the edge of the cluster, just as air bubbles in water make their way to the surface. Researchers also found evidence that this explosion was not a one-time event. "We detected a small, bright radio source near the center of the cluster that indicates a new explosion has occurred recently," said team member Michael Wise of the Massachusetts Institute of Technology in Cambridge, "so the cycle of eruption is apparently continuing." Though dim, the ghost cavities are not completely empty. They contain a mixture of very hot gas, high-energy particles and magnetic fields -- otherwise the cavities would have collapsed under the pressure of the surrounding hot gas. "Ghost cavities may be the vessels that transport magnetic fields generated in a disk surrounding a giant black hole to the cluster gas that is spread over a region a billion times larger," said McNamara. If dozens of these cavities were created over the life of the cluster, they could explain the surprisingly strong magnetic field of the multimillion-degree gas that pervades the cluster. Galaxy clusters are the largest known gravitationally bound structures in the universe. Hundreds of galaxies swarm in giant reservoirs of multimillion-degree gas that radiates most of its energy in X-rays. Over the course of billions of years some of the gas should cool and sink toward a galaxy in the center of the cluster where it could trigger an outburst in the vicinity of the central massive black hole. Chandra observed Abell 2597 on July 28, 2000,for 40,000 seconds with the Advanced CCD Imaging Spectrometer (ACIS) instrument. Pennsylvania State University, University Park, and MIT developed the instrument for NASA. In addition to a group of astronomers from the Space Telescope Science Institute, Baltimore, and the University of Virginia, Charlottesville, the team included: Paul Nulsen, University of Wollagong, Australia; Larry David, Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; Chris Carilli, National Radio Astronomy Observatory, Socorro, N.M.; and Craig Sarazin, University of Virginia. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program, and TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass.

Interdisciplinary model of care (RADICALS) for early detection and management of chronic obstructive pulmonary disease (COPD) in Australian primary care: study protocol for a cluster randomised controlled trial

PubMed Central

Liang, Jenifer; Abramson, Michael J; Zwar, Nicholas; Russell, Grant; Holland, Anne E; Bonevski, Billie; Mahal, Ajay; van Hecke, Benjamin; Phillips, Kirsten; Eustace, Paula; Paul, Eldho; Petrie, Kate; Wilson, Sally; George, Johnson

2017-01-01

Introduction Up to half of all smokers develop clinically significant chronic obstructive pulmonary disease (COPD). Gaps exist in the implementation and uptake of evidence-based guidelines for managing COPD in primary care. We describe the methodology of a cluster randomised controlled trial (cRCT) evaluating the efficacy and cost-effectiveness of an interdisciplinary model of care aimed at reducing the burden of smoking and COPD in Australian primary care settings. Methods and analysis A cRCT is being undertaken to evaluate an interdisciplinary model of care (RADICALS — Review of Airway Dysfunction and Interdisciplinary Community-based care of Adult Long-term Smokers). General practice clinics across Melbourne, Australia, are identified and randomised to the intervention group (RADICALS) or usual care. Patients who are current or ex-smokers, of at least 10 pack years, including those with an existing diagnosis of COPD, are being recruited to identify 280 participants with a spirometry-confirmed diagnosis of COPD. Handheld lung function devices are being used to facilitate case-finding. RADICALS includes individualised smoking cessation support, home-based pulmonary rehabilitation and home medicines review. Patients at control group sites receive usual care and Quitline referral, as appropriate. Follow-ups occur at 6 and 12 months from baseline to assess changes in quality of life, abstinence rates, health resource utilisation, symptom severity and lung function. The primary outcome is change in St George’s Respiratory Questionnaire score of patients with COPD at 6 months from baseline. Ethics and dissemination This project has been approved by the Monash University Human Research Ethics Committee and La Trobe University Human Ethics Committee (CF14/1018 – 2014000433). Results of the study will be disseminated in peer-reviewed journals and research conferences. If the intervention is successful, the RADICALS programme could potentially be integrated into general practices across Australia and sustained over time. Trial registration number ACTRN12614001155684; Pre-results. PMID:28928190

Toward the 21st Century: Preparing Proactive Visionary Transformational Leaders for Building Learning Communities. Human Resource Development. Orange County Cluster.

ERIC Educational Resources Information Center

Groff, Warren H.

This document describes the Orange County Cluster human resources development (HRD) seminar that was conducted as part of Nova University's nontraditional practitioner-oriented, problem-solving, field-based distance education program in higher education. Discussed first are HRD in the agricultural and business industrial eras and changing HRD…

Tobacco, Marijuana, and Alcohol Use in University Students: A Cluster Analysis

ERIC Educational Resources Information Center

Primack, Brian A.; Kim, Kevin H.; Shensa, Ariel; Sidani, Jaime E.; Barnett, Tracey E.; Switzer, Galen E.

2012-01-01

Objective: Segmentation of populations may facilitate development of targeted substance abuse prevention programs. The authors aimed to partition a national sample of university students according to profiles based on substance use. Participants: The authors used 2008-2009 data from the National College Health Assessment from the American College…

Quality-based Multimodal Classification Using Tree-Structured Sparsity

DTIC Science & Technology

2014-03-08

Pennsylvania State University soheil@psu.edu Asok Ray Pennsylvania State University axr2@psu.edu@psu.edu Nasser M. Nasrabadi Army Research Laboratory...clustering for on- line fault detection and isolation. Applied Intelligence, 35(2):269–284, 2011. 4 [2] S. Bahrampour, A. Ray , S. Sarkar, T. Damarla, and N

Astronomers Take the Measure of Dark Matter in the universe

NASA Astrophysics Data System (ADS)

2001-09-01

Using NASA's Chandra X-ray Observatory, astronomers have obtained their most accurate determination to date of the amount of dark matter in galaxy clusters, the most massive objects in the universe. The results provide an important step towards a precise measurement of the total matter density of the universe. These results were presented today by Steven W. Allen of the Institute of Astronomy in Cambridge, UK at a press conference at the `Two Years of Science with Chandra' symposium in Washington, DC. Allen and his colleagues Robert W. Schmidt and Andrew C. Fabian at the Institute of Astronomy observed a carefully chosen sample of five of the largest clusters of galaxies known, whose distances range from 1.5 to 4 billion light years. The team made temperature maps of the hot multimillion-degree gas that fills the clusters. "The temperature maps can be used to determine the mass needed to prevent the hot gas from escaping the clusters" explained Allen. "We found that the stars in the galaxies and hot gas together contribute only about 13 percent of the mass. The rest must be in the form of dark matter." The nature of the dark matter is not known, but most astronomers think that it is in the form of an as yet unknown type of elementary particle that contributes to gravity through its mass but otherwise interacts weakly with normal matter. These dark matter particles are often called WIMPs, an acronym for `weakly interacting massive particles'. Clusters of galaxies are vast concentrations of galaxies, hot gas and dark matter spanning millions of light years, held together by gravity. Because of their size, clusters of galaxies are thought to provide a fair sample of the proportion of dark matter in the universe as a whole. "The implication of our results is that we live in a low-density universe" said Allen. "The total mass-density is only about thirty percent of that needed to stop the universe from expanding forever." The result reinforces recent findings from measurements of the cosmic microwave background radiation, the large-scale distribution of galaxies, and the properties of distant supernovas. The Institute of Astronomy team minimized systematic errors in their work by placing independent constraints on the masses of the clusters using data from NASA's Hubble Space Telescope and the Canada-France-Hawaii Telescope atop Mauna Kea, HI. The new Chandra results also show how the average X-ray luminosity and temperature of the hot gas varies with the mass of a cluster. These findings should allow astronomers to use the data from large cluster catalogues, for which only X-ray luminosities are generally available, to get even more accurate measurements of the mean mass density of the universe, and to understand further the processes by which clusters form and grow. The Chandra observations were carried out using the Advanced CCD Imaging Spectrometer, which was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University, University Park. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program, and TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov

[Research on K-means clustering segmentation method for MRI brain image based on selecting multi-peaks in gray histogram].

PubMed

Chen, Zhaoxue; Yu, Haizhong; Chen, Hao

2013-12-01

To solve the problem of traditional K-means clustering in which initial clustering centers are selected randomly, we proposed a new K-means segmentation algorithm based on robustly selecting 'peaks' standing for White Matter, Gray Matter and Cerebrospinal Fluid in multi-peaks gray histogram of MRI brain image. The new algorithm takes gray value of selected histogram 'peaks' as the initial K-means clustering center and can segment the MRI brain image into three parts of tissue more effectively, accurately, steadily and successfully. Massive experiments have proved that the proposed algorithm can overcome many shortcomings caused by traditional K-means clustering method such as low efficiency, veracity, robustness and time consuming. The histogram 'peak' selecting idea of the proposed segmentootion method is of more universal availability.

Topology control algorithm for wireless sensor networks based on Link forwarding

NASA Astrophysics Data System (ADS)

Pucuo, Cairen; Qi, Ai-qin

2018-03-01

The research of topology control could effectively save energy and increase the service life of network based on wireless sensor. In this paper, a arithmetic called LTHC (link transmit hybrid clustering) based on link transmit is proposed. It decreases expenditure of energy by changing the way of cluster-node’s communication. The idea is to establish a link between cluster and SINK node when the cluster is formed, and link-node must be non-cluster. Through the link, cluster sends information to SINK nodes. For the sake of achieving the uniform distribution of energy on the network, prolongate the network survival time, and improve the purpose of communication, the communication will cut down much more expenditure of energy for cluster which away from SINK node. In the two aspects of improving the traffic and network survival time, we find that the LTCH is far superior to the traditional LEACH by experiments.

Implementation of evidence-based weekend service recommendations for allied health managers: a cluster randomised controlled trial protocol.

PubMed

Sarkies, Mitchell N; White, Jennifer; Morris, Meg E; Taylor, Nicholas F; Williams, Cylie; O'Brien, Lisa; Martin, Jenny; Bardoel, Anne; Holland, Anne E; Carey, Leeanne; Skinner, Elizabeth H; Bowles, Kelly-Ann; Grant, Kellie; Philip, Kathleen; Haines, Terry P

2018-04-24

It is widely acknowledged that health policy and practice do not always reflect current research evidence. Whether knowledge transfer from research to practice is more successful when specific implementation approaches are used remains unclear. A model to assist engagement of allied health managers and clinicians with research implementation could involve disseminating evidence-based policy recommendations, along with the use of knowledge brokers. We developed such a model to aid decision-making for the provision of weekend allied health services. This protocol outlines the design and methods for a multi-centre cluster randomised controlled trial to evaluate the success of research implementation strategies to promote evidence-informed weekend allied health resource allocation decisions, especially in hospital managers. This multi-centre study will be a three-group parallel cluster randomised controlled trial. Allied health managers from Australian and New Zealand hospitals will be randomised to receive either (1) an evidence-based policy recommendation document to guide weekend allied health resource allocation decisions, (2) the same policy recommendation document with support from a knowledge broker to help implement weekend allied health policy recommendations, or (3) a usual practice control group. The primary outcome will be alignment of weekend allied health service provision with policy recommendations. This will be measured by the number of allied health service events (occasions of service) occurring on weekends as a proportion of total allied health service events for the relevant hospital wards at baseline and 12-month follow-up. Evidence-based policy recommendation documents communicate key research findings in an accessible format. This comparatively low-cost research implementation strategy could be combined with using a knowledge broker to work collaboratively with decision-makers to promote knowledge transfer. The results will assist managers to make decisions on resource allocation, based on evidence. More generally, the findings will inform the development of an allied health model for translating research into practice. This trial is registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) ( ACTRN12618000029291 ). Universal Trial Number (UTN): U1111-1205-2621.

Simultaneous gains tuning in boiler/turbine PID-based controller clusters using iterative feedback tuning methodology.

PubMed

Zhang, Shu; Taft, Cyrus W; Bentsman, Joseph; Hussey, Aaron; Petrus, Bryan

2012-09-01

Tuning a complex multi-loop PID based control system requires considerable experience. In today's power industry the number of available qualified tuners is dwindling and there is a great need for better tuning tools to maintain and improve the performance of complex multivariable processes. Multi-loop PID tuning is the procedure for the online tuning of a cluster of PID controllers operating in a closed loop with a multivariable process. This paper presents the first application of the simultaneous tuning technique to the multi-input-multi-output (MIMO) PID based nonlinear controller in the power plant control context, with the closed-loop system consisting of a MIMO nonlinear boiler/turbine model and a nonlinear cluster of six PID-type controllers. Although simplified, the dynamics and cross-coupling of the process and the PID cluster are similar to those used in a real power plant. The particular technique selected, iterative feedback tuning (IFT), utilizes the linearized version of the PID cluster for signal conditioning, but the data collection and tuning is carried out on the full nonlinear closed-loop system. Based on the figure of merit for the control system performance, the IFT is shown to deliver performance favorably comparable to that attained through the empirical tuning carried out by an experienced control engineer. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Constraints on the Energy Density Content of the Universe Using Only Clusters of Galaxies

NASA Technical Reports Server (NTRS)

Molnar, Sandor M.; Haiman, Zoltan; Birkinshaw, Mark

2003-01-01

We demonstrate that it is possible to constrain the energy content of the Universe with high accuracy using observations of clusters of galaxies only. The degeneracies in the cosmological parameters are lifted by combining constraints from different observables of galaxy clusters. We show that constraints on cosmological parameters from galaxy cluster number counts as a function of redshift and accurate angular diameter distance measurements to clusters are complementary to each other and their combination can constrain the energy density content of the Universe well. The number counts can be obtained from X-ray and/or SZ (Sunyaev-Zeldovich effect) surveys, the angular diameter distances can be determined from deep observations of the intra-cluster gas using their thermal bremsstrahlung X-ray emission and the SZ effect (X-SZ method). In this letter we combine constraints from simulated cluster number counts expected from a 12 deg2 SZ cluster survey and constraints from simulated angular diameter distance measurements based on using the X-SZ method assuming an expected accuracy of 7% in the angular diameter distance determination of 70 clusters with redshifts less than 1.5. We find that R, can be determined within about 25%, A within 20%, and w within 16%. Any cluster survey can be used to select clusters for high accuracy distance measurements, but we assumed accurate angular diameter distance measurements for only 70 clusters since long observations are necessary to achieve high accuracy in distance measurements. Thus the question naturally arises: How to select clusters of galaxies for accurate diameter distance determinations? In this letter, as an example, we demonstrate that it is possible to optimize this selection changing the number of clusters observed, and the upper cut off of their redshift range. We show that constraints on cosmological parameters from combining cluster number counts and angular diameter distance measurements, as opposed to general expectations, will not improve substantially selecting clusters with redshifts higher than one. This important conclusion allow us to restrict our cluster sample to clusters closer than one, in a range where the observational time for accurate distance measurements are more manageable. Subject headings: cosmological parameters - cosmology: theory - galaxies: clusters: general - X-rays: galaxies: clusters

Community involvement in dengue vector control: cluster randomised trial.

PubMed

Vanlerberghe, V; Toledo, M E; Rodríguez, M; Gómez, D; Baly, A; Benítez, J R; Van der Stuyft, P

2010-01-01

To assess the effectiveness of an integrated community based environmental management strategy to control Aedes aegypti, the vector of dengue, compared with a routine strategy. Design Cluster randomised trial. Setting Guantanamo, Cuba. Participants 32 circumscriptions (around 2000 inhabitants each). Interventions The circumscriptions were randomly allocated to control clusters (n=16) comprising routine Aedes control programme (entomological surveillance, source reduction, selective adulticiding, and health education) and to intervention clusters (n=16) comprising the routine Aedes control programme combined with a community based environmental management approach. The primary outcome was levels of Aedes infestation: house index (number of houses positive for at least one container with immature stages of Ae aegypti per 100 inspected houses), Breteau index (number of containers positive for immature stages of Ae aegypti per 100 inspected houses), and the pupae per inhabitant statistic (number of Ae aegypti pupae per inhabitant). All clusters were subjected to the intended intervention; all completed the study protocol up to February 2006 and all were included in the analysis. At baseline the Aedes infestation levels were comparable between intervention and control clusters: house index 0.25% v 0.20%, pupae per inhabitant 0.44 x 10(-3) v 0.29 x 10(-3). At the end of the intervention these indices were significantly lower in the intervention clusters: rate ratio for house indices 0.49 (95% confidence interval 0.27 to 0.88) and rate ratio for pupae per inhabitant 0.27 (0.09 to 0.76). A community based environmental management embedded in a routine control programme was effective at reducing levels of Aedes infestation. Trial Registration Current Controlled Trials ISRCTN88405796.

Community involvement in dengue vector control: cluster randomised trial.

PubMed

Vanlerberghe, V; Toledo, M E; Rodríguez, M; Gomez, D; Baly, A; Benitez, J R; Van der Stuyft, P

2009-06-09

To assess the effectiveness of an integrated community based environmental management strategy to control Aedes aegypti, the vector of dengue, compared with a routine strategy. Cluster randomised trial. Guantanamo, Cuba. 32 circumscriptions (around 2000 inhabitants each). The circumscriptions were randomly allocated to control clusters (n=16) comprising routine Aedes control programme (entomological surveillance, source reduction, selective adulticiding, and health education) and to intervention clusters (n=16) comprising the routine Aedes control programme combined with a community based environmental management approach. The primary outcome was levels of Aedes infestation: house index (number of houses positive for at least one container with immature stages of Ae aegypti per 100 inspected houses), Breteau index (number of containers positive for immature stages of Ae aegypti per 100 inspected houses), and the pupae per inhabitant statistic (number of Ae aegypti pupae per inhabitant). All clusters were subjected to the intended intervention; all completed the study protocol up to February 2006 and all were included in the analysis. At baseline the Aedes infestation levels were comparable between intervention and control clusters: house index 0.25% v 0.20%, pupae per inhabitant 0.44x10(-3) v 0.29x10(-3). At the end of the intervention these indices were significantly lower in the intervention clusters: rate ratio for house indices 0.49 (95% confidence interval 0.27 to 0.88) and rate ratio for pupae per inhabitant 0.27 (0.09 to 0.76). A community based environmental management embedded in a routine control programme was effective at reducing levels of Aedes infestation. Current Controlled Trials ISRCTN88405796.

Private Universities in Kenya Seek Alternative Ways to Manage Change in Teacher Education Curriculum in Compliance with the Commission for University Education Reforms

ERIC Educational Resources Information Center

Amimo, Catherine Adhiambo

2016-01-01

This study investigated management of change in teacher education curriculum in Private universities in Kenya. The study employed a concurrent mixed methods design that is based on the use of both quantitative and qualitative approaches. A multi-stage sampling process which included purposive, convenience, cluster, and snowball sampling methods…

Feedback on oral presentations during pediatric clerkships: a randomized controlled trial.

PubMed

Sox, Colin M; Dell, Michael; Phillipi, Carrie A; Cabral, Howard J; Vargas, Gabriela; Lewin, Linda O

2014-11-01

To measure the effects of participating in structured oral presentation evaluation sessions early in pediatric clerkships on students' subsequent presentations. We conducted a single-blind, 3-arm, cluster randomized controlled trial during pediatric clerkships at Boston University School of Medicine, University of Maryland School of Medicine, Oregon Health & Science University, and Case Western Reserve University School of Medicine. Blocks of students at each school were randomly assigned to experience either (1) no formal presentation feedback (control) or a small-group presentation feedback session early in pediatric clerkships in which students gave live presentations and received feedback from faculty who rated their presentations by using a (2) single-item (simple) or (3) 18-item (detailed) evaluation form. At the clerkship end, overall quality of subjects' presentations was rated by faculty blinded to randomization status, and subjects reported whether their presentations had improved. Analyses included multivariable linear and logistic regressions clustered on clerkship block that controlled for medical school. A total of 476 participants were evenly divided into the 3 arms, which had similar characteristics. Compared with controls, presentation quality was significantly associated with participating in detailed (coefficient: 0.38; 95% confidence interval [CI]: 0.07-0.69) but not simple (coefficient: 0.16; 95% CI: -0.12-0.43) feedback sessions. Similarly, student self-report of presentation improvement was significantly associated with participating in detailed (odds ratio: 2.16; 95% CI: 1.11-4.18] but not simple (odds ratio: 1.89; 95% CI: 0.91-3.93) feedback sessions. Small-group presentation feedback sessions led by faculty using a detailed evaluation form resulted in clerkship students delivering oral presentations of higher quality compared with controls. Copyright © 2014 by the American Academy of Pediatrics.

Photometric redshifts as a tool for studying the Coma cluster galaxy populations

NASA Astrophysics Data System (ADS)

Adami, C.; Ilbert, O.; Pelló, R.; Cuillandre, J. C.; Durret, F.; Mazure, A.; Picat, J. P.; Ulmer, M. P.

2008-12-01

Aims: We apply photometric redshift techniques to an investigation of the Coma cluster galaxy luminosity function (GLF) at faint magnitudes, in particular in the u* band where basically no studies are presently available at these magnitudes. Methods: Cluster members were selected based on probability distribution function from photometric redshift calculations applied to deep u^*, B, V, R, I images covering a region of almost 1 deg2 (completeness limit R ~ 24). In the area covered only by the u* image, the GLF was also derived after a statistical background subtraction. Results: Global and local GLFs in the B, V, R, and I bands obtained with photometric redshift selection are consistent with our previous results based on a statistical background subtraction. The GLF in the u* band shows an increase in the faint end slope towards the outer regions of the cluster. The analysis of the multicolor type spatial distribution reveals that late type galaxies are distributed in clumps in the cluster outskirts, where X-ray substructures are also detected and where the GLF in the u* band is steeper. Conclusions: We can reproduce the GLFs computed with classical statistical subtraction methods by applying a photometric redshift technique. The u* GLF slope is steeper in the cluster outskirts, varying from α ~ -1 in the cluster center to α ~ -2 in the cluster periphery. The concentrations of faint late type galaxies in the cluster outskirts could explain these very steep slopes, assuming a short burst of star formation in these galaxies when entering the cluster. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is also partly based on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. Also based on data from W. M. Keck Observatory which is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA. It was made possible by the generous financial support of the W. M. Keck Foundation.

Coma cluster of galaxies

NASA Technical Reports Server (NTRS)

1999-01-01

Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

Dynamic Key Management Schemes for Secure Group Access Control Using Hierarchical Clustering in Mobile Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Tsaur, Woei-Jiunn; Pai, Haw-Tyng

2008-11-01

The applications of group computing and communication motivate the requirement to provide group access control in mobile ad hoc networks (MANETs). The operation in MANETs' groups performs a decentralized manner and accommodated membership dynamically. Moreover, due to lack of centralized control, MANETs' groups are inherently insecure and vulnerable to attacks from both within and outside the groups. Such features make access control more challenging in MANETs. Recently, several researchers have proposed group access control mechanisms in MANETs based on a variety of threshold signatures. However, these mechanisms cannot actually satisfy MANETs' dynamic environments. This is because the threshold-based mechanisms cannot be achieved when the number of members is not up to the threshold value. Hence, by combining the efficient elliptic curve cryptosystem, self-certified public key cryptosystem and secure filter technique, we construct dynamic key management schemes based on hierarchical clustering for securing group access control in MANETs. Specifically, the proposed schemes can constantly accomplish secure group access control only by renewing the secure filters of few cluster heads, when a cluster head joins or leaves a cross-cluster. In such a new way, we can find that the proposed group access control scheme can be very effective for securing practical applications in MANETs.

Blind Quantum Signature with Controlled Four-Particle Cluster States

NASA Astrophysics Data System (ADS)

Li, Wei; Shi, Jinjing; Shi, Ronghua; Guo, Ying

2017-08-01

A novel blind quantum signature scheme based on cluster states is introduced. Cluster states are a type of multi-qubit entangled states and it is more immune to decoherence than other entangled states. The controlled four-particle cluster states are created by acting controlled-Z gate on particles of four-particle cluster states. The presented scheme utilizes the above entangled states and simplifies the measurement basis to generate and verify the signature. Security analysis demonstrates that the scheme is unconditional secure. It can be employed to E-commerce systems in quantum scenario.

Behavioral Health Risk Profiles of Undergraduate University Students in England, Wales, and Northern Ireland: A Cluster Analysis.

PubMed

El Ansari, Walid; Ssewanyana, Derrick; Stock, Christiane

2018-01-01

Limited research has explored clustering of lifestyle behavioral risk factors (BRFs) among university students. This study aimed to explore clustering of BRFs, composition of clusters, and the association of the clusters with self-rated health and perceived academic performance. We assessed (BRFs), namely tobacco smoking, physical inactivity, alcohol consumption, illicit drug use, unhealthy nutrition, and inadequate sleep, using a self-administered general Student Health Survey among 3,706 undergraduates at seven UK universities. A two-step cluster analysis generated: Cluster 1 (the high physically active and health conscious) with very high health awareness/consciousness, good nutrition, and physical activity (PA), and relatively low alcohol, tobacco, and other drug (ATOD) use. Cluster 2 (the abstinent) had very low ATOD use, high health awareness, good nutrition, and medium high PA. Cluster 3 (the moderately health conscious) included the highest regard for healthy eating, second highest fruit/vegetable consumption, and moderately high ATOD use. Cluster 4 (the risk taking) showed the highest ATOD use, were the least health conscious, least fruit consuming, and attached the least importance on eating healthy. Compared to the healthy cluster (Cluster 1), students in other clusters had lower self-rated health, and particularly, students in the risk taking cluster (Cluster 4) reported lower academic performance. These associations were stronger for men than for women. Of the four clusters, Cluster 4 had the youngest students. Our results suggested that prevention among university students should address multiple BRFs simultaneously, with particular focus on the younger students.

Conveyor Performance based on Motor DC 12 Volt Eg-530ad-2f using K-Means Clustering

NASA Astrophysics Data System (ADS)

Arifin, Zaenal; Artini, Sri DP; Much Ibnu Subroto, Imam

2017-04-01

To produce goods in industry, a controlled tool to improve production is required. Separation process has become a part of production process. Separation process is carried out based on certain criteria to get optimum result. By knowing the characteristics performance of a controlled tools in separation process the optimum results is also possible to be obtained. Clustering analysis is popular method for clustering data into smaller segments. Clustering analysis is useful to divide a group of object into a k-group in which the member value of the group is homogeny or similar. Similarity in the group is set based on certain criteria. The work in this paper based on K-Means method to conduct clustering of loading in the performance of a conveyor driven by a dc motor 12 volt eg-530-2f. This technique gives a complete clustering data for a prototype of conveyor driven by dc motor to separate goods in term of height. The parameters involved are voltage, current, time of travelling. These parameters give two clusters namely optimal cluster with center of cluster 10.50 volt, 0.3 Ampere, 10.58 second, and unoptimal cluster with center of cluster 10.88 volt, 0.28 Ampere and 40.43 second.

Classification via Clustering for Predicting Final Marks Based on Student Participation in Forums

ERIC Educational Resources Information Center

Lopez, M. I.; Luna, J. M.; Romero, C.; Ventura, S.

2012-01-01

This paper proposes a classification via clustering approach to predict the final marks in a university course on the basis of forum data. The objective is twofold: to determine if student participation in the course forum can be a good predictor of the final marks for the course and to examine whether the proposed classification via clustering…

The bacterial species definition in the genomic era

PubMed Central

Konstantinidis, Konstantinos T; Ramette, Alban; Tiedje, James M

2006-01-01

The bacterial species definition, despite its eminent practical significance for identification, diagnosis, quarantine and diversity surveys, remains a very difficult issue to advance. Genomics now offers novel insights into intra-species diversity and the potential for emergence of a more soundly based system. Although we share the excitement, we argue that it is premature for a universal change to the definition because current knowledge is based on too few phylogenetic groups and too few samples of natural populations. Our analysis of five important bacterial groups suggests, however, that more stringent standards for species may be justifiable when a solid understanding of gene content and ecological distinctiveness becomes available. Our analysis also reveals what is actually encompassed in a species according to the current standards, in terms of whole-genome sequence and gene-content diversity, and shows that this does not correspond to coherent clusters for the environmental Burkholderia and Shewanella genera examined. In contrast, the obligatory pathogens, which have a very restricted ecological niche, do exhibit clusters. Therefore, the idea of biologically meaningful clusters of diversity that applies to most eukaryotes may not be universally applicable in the microbial world, or if such clusters exist, they may be found at different levels of distinction. PMID:17062412

Algorithms and software used in selecting structure of machine-training cluster based on neurocomputers

NASA Astrophysics Data System (ADS)

Romanchuk, V. A.; Lukashenko, V. V.

2018-05-01

The technique of functioning of a control system by a computing cluster based on neurocomputers is proposed. Particular attention is paid to the method of choosing the structure of the computing cluster due to the fact that the existing methods are not effective because of a specialized hardware base - neurocomputers, which are highly parallel computer devices with an architecture different from the von Neumann architecture. A developed algorithm for choosing the computational structure of a cloud cluster is described, starting from the direction of data transfer in the flow control graph of the program and its adjacency matrix.

Cluster-based control of a separating flow over a smoothly contoured ramp

NASA Astrophysics Data System (ADS)

Kaiser, Eurika; Noack, Bernd R.; Spohn, Andreas; Cattafesta, Louis N.; Morzyński, Marek

2017-12-01

The ability to manipulate and control fluid flows is of great importance in many scientific and engineering applications. The proposed closed-loop control framework addresses a key issue of model-based control: The actuation effect often results from slow dynamics of strongly nonlinear interactions which the flow reveals at timescales much longer than the prediction horizon of any model. Hence, we employ a probabilistic approach based on a cluster-based discretization of the Liouville equation for the evolution of the probability distribution. The proposed methodology frames high-dimensional, nonlinear dynamics into low-dimensional, probabilistic, linear dynamics which considerably simplifies the optimal control problem while preserving nonlinear actuation mechanisms. The data-driven approach builds upon a state space discretization using a clustering algorithm which groups kinematically similar flow states into a low number of clusters. The temporal evolution of the probability distribution on this set of clusters is then described by a control-dependent Markov model. This Markov model can be used as predictor for the ergodic probability distribution for a particular control law. This probability distribution approximates the long-term behavior of the original system on which basis the optimal control law is determined. We examine how the approach can be used to improve the open-loop actuation in a separating flow dominated by Kelvin-Helmholtz shedding. For this purpose, the feature space, in which the model is learned, and the admissible control inputs are tailored to strongly oscillatory flows.

Applying the Anderson-Darling test to suicide clusters: evidence of contagion at U. S. universities?

PubMed

MacKenzie, Donald W

2013-01-01

Suicide clusters at Cornell University and the Massachusetts Institute of Technology (MIT) prompted popular and expert speculation of suicide contagion. However, some clustering is to be expected in any random process. This work tested whether suicide clusters at these two universities differed significantly from those expected under a homogeneous Poisson process, in which suicides occur randomly and independently of one another. Suicide dates were collected for MIT and Cornell for 1990-2012. The Anderson-Darling statistic was used to test the goodness-of-fit of the intervals between suicides to distribution expected under the Poisson process. Suicides at MIT were consistent with the homogeneous Poisson process, while those at Cornell showed clustering inconsistent with such a process (p = .05). The Anderson-Darling test provides a statistically powerful means to identify suicide clustering in small samples. Practitioners can use this method to test for clustering in relevant communities. The difference in clustering behavior between the two institutions suggests that more institutions should be studied to determine the prevalence of suicide clustering in universities and its causes.

An effort to 'leverage' the effect of participation in a mass event on physical activity.

PubMed

Lane, Aoife; Murphy, Niamh; Bauman, Adrian

2015-09-01

Despite the considerable interest in community-based physical activity (PA) interventions, there is a lack of clarity on which strategies are most effective and most likely to work in different contexts. The purpose of this study was to use existing community resources to promote PA in a population sample of insufficiently active women using a cluster RCT design. Participants (n = 402) were grouped into 32 geographical-based clusters, which were randomly allocated into 16 intervention (n = 193) and 16 control (n = 209) regions. The intervention was delivered in conjunction with regional units of the Irish Sports Council; participants received a pack containing tailored information about local PA options in their community, training plans, stage-matched behaviour change booklets and a pedometer. Control participants received health promotion leaflets. Evaluation was conducted using the RE-AIM framework to assess both effectiveness and generalizability. Repeated measures ANOVAs with adjustment for clustering revealed that both groups displayed an approximate 39 min increase in PA, but decreases in sitting were greater in the intervention group than the control group (32.9 versus 1.2 min). Recall of materials was high ranging between 85 and 97% for the various intervention components. Finally, those who received higher doses of the intervention (three or more components) reported an approximate 50 min increase in PA compared with 18 min among those who did not use any aspect of the intervention. While no clear intervention effect was evident, this research was successful in linking and implementing good research design with PA promoting networks. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Spanish Version of the Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Adolescents (UP-A) Adapted as a School-Based Anxiety and Depression Prevention Program: Study Protocol for a Cluster Randomized Controlled Trial.

PubMed

García-Escalera, Julia; Valiente, Rosa M; Chorot, Paloma; Ehrenreich-May, Jill; Kennedy, Sarah M; Sandín, Bonifacio

2017-08-21

Anxiety and depression are common, impairing conditions that evidence high comorbidity rates in adolescence. The Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Adolescents (UP-A) is one of the few existing resources aimed at applying transdiagnostic treatment principles to target core dysfunctions associated with both anxiety and depression within a single protocol. To our knowledge, this is the first study examining the efficacy of the UP-A adapted as a universal preventive intervention program. The primary aim of this study is to examine whether the Spanish version of the UP-A is more effective than a waitlist (WL) control group in reducing and preventing symptoms of anxiety and depression when employed as a universal, classroom-based preventive intervention. The secondary aim is to investigate changes in a broad range of secondary outcome measures, including negative and positive affect, anxiety sensitivity, emotional avoidance, top problems ratings, school grades, depression and anxiety-related interference, self-esteem, life satisfaction, quality of life, conduct problems, hyperactivity/inattention symptoms, peer problems, prosocial behavior, school adjustment, and discipline problems. Other aims are to assess a range of possible predictors of intervention effects and to examine the feasibility and the acceptability of implementing UP-A in a prevention group format and in a school setting. A cluster, randomized, WL, controlled trial design with classroom as the unit of randomization was used in this study. Five classes including a total of 152 adolescents were randomized to the experimental or WL control groups. Participants in the experimental group received 9 55-minute sessions delivered by advanced doctoral and masters students in clinical psychology. The WL control group will receive the intervention once the 3-month follow-up assessment is completed. We have recruited participants to the cluster randomized controlled trial (RCT) and have conducted the intervention with the experimental group. We expect the WL control group to complete the intervention in July 2017. Data analysis will take place during the second semester of 2017. We expect the experimental group to outperform the WL control group at post-intervention and 3-month follow-up. We also expect the WL control group to show improvements in primary and secondary outcome measures after receiving the intervention. Results will have implications for researchers, families, and education providers. Clinicaltrials.gov NCT03123991; https://clinicaltrials.gov/ct2/show/NCT03123991 (Archived by WebCite at http://www.webcitation.org/6qp7GIzcR). ©Julia García-Escalera, Rosa M Valiente, Paloma Chorot, Jill Ehrenreich-May, Sarah M Kennedy, Bonifacio Sandín. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 21.08.2017.

The Spanish Version of the Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Adolescents (UP-A) Adapted as a School-Based Anxiety and Depression Prevention Program: Study Protocol for a Cluster Randomized Controlled Trial

PubMed Central

García-Escalera, Julia; Valiente, Rosa M; Ehrenreich-May, Jill; Kennedy, Sarah M; Sandín, Bonifacio

2017-01-01

Background Anxiety and depression are common, impairing conditions that evidence high comorbidity rates in adolescence. The Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Adolescents (UP-A) is one of the few existing resources aimed at applying transdiagnostic treatment principles to target core dysfunctions associated with both anxiety and depression within a single protocol. To our knowledge, this is the first study examining the efficacy of the UP-A adapted as a universal preventive intervention program. Objective The primary aim of this study is to examine whether the Spanish version of the UP-A is more effective than a waitlist (WL) control group in reducing and preventing symptoms of anxiety and depression when employed as a universal, classroom-based preventive intervention. The secondary aim is to investigate changes in a broad range of secondary outcome measures, including negative and positive affect, anxiety sensitivity, emotional avoidance, top problems ratings, school grades, depression and anxiety-related interference, self-esteem, life satisfaction, quality of life, conduct problems, hyperactivity/inattention symptoms, peer problems, prosocial behavior, school adjustment, and discipline problems. Other aims are to assess a range of possible predictors of intervention effects and to examine the feasibility and the acceptability of implementing UP-A in a prevention group format and in a school setting. Methods A cluster, randomized, WL, controlled trial design with classroom as the unit of randomization was used in this study. Five classes including a total of 152 adolescents were randomized to the experimental or WL control groups. Participants in the experimental group received 9 55-minute sessions delivered by advanced doctoral and masters students in clinical psychology. The WL control group will receive the intervention once the 3-month follow-up assessment is completed. Results We have recruited participants to the cluster randomized controlled trial (RCT) and have conducted the intervention with the experimental group. We expect the WL control group to complete the intervention in July 2017. Data analysis will take place during the second semester of 2017. Conclusions We expect the experimental group to outperform the WL control group at post-intervention and 3-month follow-up. We also expect the WL control group to show improvements in primary and secondary outcome measures after receiving the intervention. Results will have implications for researchers, families, and education providers. Trial Registration Clinicaltrials.gov NCT03123991; https://clinicaltrials.gov/ct2/show/NCT03123991 (Archived by WebCite at http://www.webcitation.org/6qp7GIzcR) PMID:28827212

Evaluating the implementation of a school-based emotional well-being programme: a cluster randomized controlled trial of Zippy's Friends for children in disadvantaged primary schools.

PubMed

Clarke, Aleisha M; Bunting, Brendan; Barry, Margaret M

2014-10-01

Schools are recognized as one of the most important settings for promoting social and emotional well-being among children and adolescents. This clustered randomized controlled trial evaluated Zippy's Friends, an international school-based emotional well-being programme, with 766 children from designated disadvantaged schools. The purpose of this study was to evaluate the immediate and long term impact of the programme and to determine the impact of implementation fidelity on programme outcomes. Teachers reported emotional literacy outcomes using the Emotional Literacy Checklist, and emotional and behavioural outcomes using the Strengths and Difficulties Questionnaire. Controlling for the hierarchical structure of the data, path analysis using structural equation modelling revealed that the programme had a significant positive impact on the children's emotional literacy scores including significant improvements in the subscale scores of self-awareness (P < 0.001), self-regulation (P < 0.01), motivation (P < 0.001) and social skills (P < 0.001) at post-intervention. These results were maintained at 12-month follow-up (P < 0.01). The programme, however, did not have a significant impact on children's emotional and behavioural problems. Analysis of programme fidelity indicated that high fidelity was directly related to improved emotional literacy scores at post-intervention. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Combined universal and selective prevention for adolescent alcohol use: a cluster randomized controlled trial.

PubMed

Teesson, M; Newton, N C; Slade, T; Carragher, N; Barrett, E L; Champion, K E; Kelly, E V; Nair, N K; Stapinski, L A; Conrod, P J

2017-07-01

No existing models of alcohol prevention concurrently adopt universal and selective approaches. This study aims to evaluate the first combined universal and selective approach to alcohol prevention. A total of 26 Australian schools with 2190 students (mean age: 13.3 years) were randomized to receive: universal prevention (Climate Schools); selective prevention (Preventure); combined prevention (Climate Schools and Preventure; CAP); or health education as usual (control). Primary outcomes were alcohol use, binge drinking and alcohol-related harms at 6, 12 and 24 months. Climate, Preventure and CAP students demonstrated significantly lower growth in their likelihood to drink and binge drink, relative to controls over 24 months. Preventure students displayed significantly lower growth in their likelihood to experience alcohol harms, relative to controls. While adolescents in both the CAP and Climate groups demonstrated slower growth in drinking compared with adolescents in the control group over the 2-year study period, CAP adolescents demonstrated faster growth in drinking compared with Climate adolescents. Findings support universal, selective and combined approaches to alcohol prevention. Particularly novel are the findings of no advantage of the combined approach over universal or selective prevention alone.

Motivational and emotional profiles in university undergraduates: a self-determination theory perspective.

PubMed

González, Antonio; Paoloni, Verónica; Donolo, Danilo; Rinaudo, Cristina

2012-11-01

Previous research has focused on specific forms of self-determined motivation or discrete class-related emotions, but few studies have simultaneously examined both constructs. The aim of this study on 472 undergraduates was twofold: to perform cluster analysis to identify homogeneous groups of motivation in the sample; and to determine the profile of each cluster for emotions and academic achievement. Cluster analysis configured four groups in terms of motivation: controlled, autonomous, both high, and both low. Each cluster revealed a distinct emotional profile, autonomous motivation being the most adaptable with high scores for academic achievement and pleasant emotions and low values for unpleasant emotions. The results are discussed in the light of their implications for academic adjustment.

NCSTRL+: Adding Multi-Discipline and Multi-Genre Support to the Dienst Protocol Using Clusters and Buckets

NASA Technical Reports Server (NTRS)

Nelson, Michael L.; Maly, Kurt; Shen, Stewart N. T.; Zubair, Mohammad

1998-01-01

We describe NCSTRL+, a unified, canonical digital library for scientific and technical information (STI). NCSTRL+ is based on the Networked Computer Science Technical Report Library (NCSTRL), a World Wide Web (WWW) accessible digital library (DL) that provides access to over 100 university departments and laboratories. NCSTRL+ implements two new technologies: cluster functionality and publishing buckets. We have extended Dienst, the protocol underlying NCSTRL, to provide the ability to cluster independent collections into a logically centralized digital library based upon subject category classification, type of organization, and genres of material. The bucket construct provides a mechanism for publishing and managing logically linked entities with multiple data forms as a single object. The NCSTRL+ prototype DL contains the holdings of NCSTRL and the NASA Technical Report Server (NTRS). The prototype demonstrates the feasibility of publishing into a multi-cluster DL, searching across clusters, and storing and presenting buckets of information.

Patient Stratification Using Electronic Health Records from a Chronic Disease Management Program.

PubMed

Chen, Robert; Sun, Jimeng; Dittus, Robert S; Fabbri, Daniel; Kirby, Jacqueline; Laffer, Cheryl L; McNaughton, Candace D; Malin, Bradley

2016-01-04

The goal of this study is to devise a machine learning framework to assist care coordination programs in prognostic stratification to design and deliver personalized care plans and to allocate financial and medical resources effectively. This study is based on a de-identified cohort of 2,521 hypertension patients from a chronic care coordination program at the Vanderbilt University Medical Center. Patients were modeled as vectors of features derived from electronic health records (EHRs) over a six-year period. We applied a stepwise regression to identify risk factors associated with a decrease in mean arterial pressure of at least 2 mmHg after program enrollment. The resulting features were subsequently validated via a logistic regression classifier. Finally, risk factors were applied to group the patients through model-based clustering. We identified a set of predictive features that consisted of a mix of demographic, medication, and diagnostic concepts. Logistic regression over these features yielded an area under the ROC curve (AUC) of 0.71 (95% CI: [0.67, 0.76]). Based on these features, four clinically meaningful groups are identified through clustering - two of which represented patients with more severe disease profiles, while the remaining represented patients with mild disease profiles. Patients with hypertension can exhibit significant variation in their blood pressure control status and responsiveness to therapy. Yet this work shows that a clustering analysis can generate more homogeneous patient groups, which may aid clinicians in designing and implementing customized care programs. The study shows that predictive modeling and clustering using EHR data can be beneficial for providing a systematic, generalized approach for care providers to tailor their management approach based upon patient-level factors.

Preventing Depression in Final Year Secondary Students: School-Based Randomized Controlled Trial

PubMed Central

Perry, Yael; Werner-Seidler, Aliza; Calear, Alison; Mackinnon, Andrew; King, Catherine; Scott, Jan; Merry, Sally; Fleming, Theresa; Stasiak, Karolina; Batterham, Philip J

2017-01-01

Background Depression often emerges for the first time during adolescence. There is accumulating evidence that universal depression prevention programs may have the capacity to reduce the impact of depression when delivered in the school environment. Objective This trial investigated the effectiveness of SPARX-R, a gamified online cognitive behavior therapy intervention for the prevention of depression relative to an attention-matched control intervention delivered to students prior to facing a significant stressor—final secondary school exams. It was hypothesized that delivering a prevention intervention in advance of a stressor would reduce depressive symptoms relative to the control group. Methods A cluster randomized controlled trial was conducted in 10 government schools in Sydney, Australia. Participants were 540 final year secondary students (mean 16.7 [SD 0.51] years), and clusters at the school level were randomly allocated to SPARX-R or the control intervention. Interventions were delivered weekly in 7 modules, each taking approximately 20 to 30 minutes to complete. The primary outcome was symptoms of depression as measured by the Major Depression Inventory. Intention-to-treat analyses were performed. Results Compared to controls, participants in the SPARX-R condition (n=242) showed significantly reduced depression symptoms relative to the control (n=298) at post-intervention (Cohen d=0.29) and 6 months post-baseline (d=0.21) but not at 18 months post-baseline (d=0.33). Conclusions This is the first trial to demonstrate a preventive effect on depressive symptoms prior to a significant and universal stressor in adolescents. It demonstrates that an online intervention delivered in advance of a stressful experience can reduce the impact of such an event on the potential development or exacerbation of depression. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12614000316606; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=365986 (Archived by WebCite at http://www.webcitation.org/ 6u7ou1aI9) PMID:29097357

Community-based control of Aedes aegypti by adoption of eco-health methods in Chennai City, India

PubMed Central

Arunachalam, Natarajan; Tyagi, Brij Kishore; Samuel, Miriam; Krishnamoorthi, R; Manavalan, R; Tewari, Satish Chandra; Ashokkumar, V; Kroeger, Axel; Sommerfeld, Johannes; Petzold, Max

2012-01-01

Background Dengue is highly endemic in Chennai city, South India, in spite of continuous vector control efforts. This intervention study was aimed at establishing the efficacy as well as the favouring and limiting factors relating to a community-based environmental intervention package to control the dengue vector Aedes aegypti. Methods A cluster randomized controlled trial was designed to measure the outcome of a new vector control package and process analysis; different data collection tools were used to determine the performance. Ten randomly selected intervention clusters (neighbourhoods with 100 houses each) were paired with ten control clusters on the basis of ecological/entomological indices and sociological parameters collected during baseline studies. In the intervention clusters, Aedes control was carried out using a community-based environmental management approach like provision of water container covers through community actors, clean-up campaigns, and dissemination of dengue information through schoolchildren. The main outcome measure was reduction in pupal indices (pupae per person index), used as a proxy measure of adult vectors, in the intervention clusters compared to the control clusters. Results At baseline, almost half the respondents did not know that dengue is serious but preventable, or that it is transmitted by mosquitoes. The stakeholder analysis showed that dengue vector control is carried out by vertically structured programmes of national, state, and local administrative bodies through fogging and larval control with temephos, without any involvement of community-based organizations, and that vector control efforts were conducted in an isolated and irregular way. The most productive container types for Aedes pupae were cement tanks, drums, and discarded containers. All ten intervention clusters with a total of 1000 houses and 4639 inhabitants received the intervention while the ten control clusters with a total of 1000 houses and 4439 inhabitants received only the routine government services and some of the information education and communication project materials. The follow-up studies showed that there was a substantial increase in dengue understanding in the intervention group with only minor knowledge changes in the control group. Community involvement and the partnership among stakeholders (particularly women’s self-help groups) worked well. After 10 months of intervention, the pupae per person index was significantly reduced to 0.004 pupae per person from 1.075 (P = 0.020) in the intervention clusters compared to control clusters. There were also significant reductions in the Stegomyia indices: the house index was reduced to 4.2%, the container index to 1.05%, and the Breteau index to 4.3 from the baseline values of 19.6, 8.91, and 30.8 in the intervention arm. Conclusion A community-based approach together with other stakeholders that promoted interventions to prevent dengue vector breeding led to a substantial reduction in dengue vector density. PMID:23318241

Community-based control of Aedes aegypti by adoption of eco-health methods in Chennai City, India.

PubMed

Arunachalam, Natarajan; Tyagi, Brij Kishore; Samuel, Miriam; Krishnamoorthi, R; Manavalan, R; Tewari, Satish Chandra; Ashokkumar, V; Kroeger, Axel; Sommerfeld, Johannes; Petzold, Max

2012-12-01

Dengue is highly endemic in Chennai city, South India, in spite of continuous vector control efforts. This intervention study was aimed at establishing the efficacy as well as the favouring and limiting factors relating to a community-based environmental intervention package to control the dengue vector Aedes aegypti. A cluster randomized controlled trial was designed to measure the outcome of a new vector control package and process analysis; different data collection tools were used to determine the performance. Ten randomly selected intervention clusters (neighbourhoods with 100 houses each) were paired with ten control clusters on the basis of ecological/entomological indices and sociological parameters collected during baseline studies. In the intervention clusters, Aedes control was carried out using a community-based environmental management approach like provision of water container covers through community actors, clean-up campaigns, and dissemination of dengue information through schoolchildren. The main outcome measure was reduction in pupal indices (pupae per person index), used as a proxy measure of adult vectors, in the intervention clusters compared to the control clusters. At baseline, almost half the respondents did not know that dengue is serious but preventable, or that it is transmitted by mosquitoes. The stakeholder analysis showed that dengue vector control is carried out by vertically structured programmes of national, state, and local administrative bodies through fogging and larval control with temephos, without any involvement of community-based organizations, and that vector control efforts were conducted in an isolated and irregular way. The most productive container types for Aedes pupae were cement tanks, drums, and discarded containers. All ten intervention clusters with a total of 1000 houses and 4639 inhabitants received the intervention while the ten control clusters with a total of 1000 houses and 4439 inhabitants received only the routine government services and some of the information education and communication project materials. The follow-up studies showed that there was a substantial increase in dengue understanding in the intervention group with only minor knowledge changes in the control group. Community involvement and the partnership among stakeholders (particularly women's self-help groups) worked well. After 10 months of intervention, the pupae per person index was significantly reduced to 0·004 pupae per person from 1·075 (P = 0·020) in the intervention clusters compared to control clusters. There were also significant reductions in the Stegomyia indices: the house index was reduced to 4·2%, the container index to 1·05%, and the Breteau index to 4·3 from the baseline values of 19·6, 8·91, and 30·8 in the intervention arm. A community-based approach together with other stakeholders that promoted interventions to prevent dengue vector breeding led to a substantial reduction in dengue vector density.

Community involvement in dengue vector control: cluster randomised trial

PubMed Central

Toledo, M E; Rodríguez, M; Gomez, D; Baly, A; Benitez, J R; Van der Stuyft, P

2009-01-01

Objective To assess the effectiveness of an integrated community based environmental management strategy to control Aedes aegypti, the vector of dengue, compared with a routine strategy. Design Cluster randomised trial. Setting Guantanamo, Cuba. Participants 32 circumscriptions (around 2000 inhabitants each). Interventions The circumscriptions were randomly allocated to control clusters (n=16) comprising routine Aedes control programme (entomological surveillance, source reduction, selective adulticiding, and health education) and to intervention clusters (n=16) comprising the routine Aedes control programme combined with a community based environmental management approach. Main outcome measures The primary outcome was levels of Aedes infestation: house index (number of houses positive for at least one container with immature stages of Ae aegypti per 100 inspected houses), Breteau index (number of containers positive for immature stages of Ae aegypti per 100 inspected houses), and the pupae per inhabitant statistic (number of Ae aegypti pupae per inhabitant). Results All clusters were subjected to the intended intervention; all completed the study protocol up to February 2006 and all were included in the analysis. At baseline the Aedes infestation levels were comparable between intervention and control clusters: house index 0.25% v 0.20%, pupae per inhabitant 0.44×10−3 v 0.29×10−3. At the end of the intervention these indices were significantly lower in the intervention clusters: rate ratio for house indices 0.49 (95% confidence interval 0.27 to 0.88) and rate ratio for pupae per inhabitant 0.27 (0.09 to 0.76). Conclusion A community based environmental management embedded in a routine control programme was effective at reducing levels of Aedes infestation. Trial registration Current Controlled Trials ISRCTN88405796. PMID:19509031

Effectiveness of school dental screening on dental visits and untreated caries among primary schoolchildren: study protocol for a cluster randomised controlled trial.

PubMed

Alayadi, Haya; Sabbah, Wael; Bernabé, Eduardo

2018-04-13

Dental caries is one of the most common diseases affecting children in Saudi Arabia despite the availability of free dental services. School-based dental screening could be a potential intervention that impacts uptake of dental services, and subsequently, dental caries' levels. The purpose of this study is to evaluate the effectiveness of two alternative approaches for school-based dental screening in promoting dental attendance and reducing untreated dental caries among primary schoolchildren. This is a cluster randomised controlled trial comparing referral of screened-positive children to a specific treatment facility (King Saud University Dental College) against conventional referral (information letter advising parents to take their child to a dentist). A thousand and ten children in 16 schools in Riyadh, Saudi Arabia, will be recruited for the trial. Schools (clusters) will be randomly selected and allocated to either group. Clinical assessment for dental caries will be conducted at baseline and after 12 months by dentists using the World Health Organisation (WHO) criteria. Data on sociodemographic, behavioural factors and children's dental visits will be collected through structured questionnaires at baseline and follow-up. The primary outcome is the change in number of teeth with untreated dental caries 12 months after referral. Secondary outcomes are the changes in the proportions of children having untreated caries and of those who visited the dentist over the trial period. This project should provide high level of evidence on the clinical benefits of school dental screening. The findings should potentially inform policies related to the continuation/implementation of school-based dental screening in Saudi Arabia. ClinicalTrials.gov , ID: NCT03345680 . Registered on 17 November 2017.

A universal harm-minimisation approach to preventing psychostimulant and cannabis use in adolescents: a cluster randomised controlled trial

PubMed Central

2014-01-01

Background Psychostimulants and cannabis are two of the three most commonly used illicit drugs by young Australians. As such, it is important to deliver prevention for these substances to prevent their misuse and to reduce associated harms. The present study aims to evaluate the feasibility and effectiveness of the universal computer-based Climate Schools: Psychostimulant and Cannabis Module. Methods A cluster randomised controlled trial was conducted with 1734 Year 10 students (mean age = 15.44 years; SD = 0.41) from 21 secondary schools in Australia. Schools were randomised to receive either the six lesson computer-based Climate Schools program or their usual health classes, including drug education, over the year. Results The Climate Schools program was shown to increase knowledge of cannabis and psychostimulants and decrease pro-drug attitudes. In the short-term the program was effective in subduing the uptake and plateauing the frequency of ecstasy use, however there were no changes in meth/amphetamine use. In addition, females who received the program used cannabis significantly less frequently than students who received drug education as usual. Finally, the Climate Schools program was related to decreasing students’ intentions to use meth/amphetamine and ecstasy in the future, however these effects did not last over time. Conclusions These findings provide support for the use of a harm-minimisation approach and computer technology as an innovative platform for the delivery of prevention education for illicit drugs in schools. The current study indicated that teachers and students enjoyed the program and that it is feasible to extend the successful Climate Schools model to the prevention of other drugs, namely cannabis and psychostimulants. Trial registration Australian and New Zealand Clinical Trials Registry ACTRN12613000492752. PMID:24943829

A universal harm-minimisation approach to preventing psychostimulant and cannabis use in adolescents: a cluster randomised controlled trial.

PubMed

Vogl, Laura Elise; Newton, Nicola Clare; Champion, Katrina Elizabeth; Teesson, Maree

2014-06-18

Psychostimulants and cannabis are two of the three most commonly used illicit drugs by young Australians. As such, it is important to deliver prevention for these substances to prevent their misuse and to reduce associated harms. The present study aims to evaluate the feasibility and effectiveness of the universal computer-based Climate Schools: Psychostimulant and Cannabis Module. A cluster randomised controlled trial was conducted with 1734 Year 10 students (mean age = 15.44 years; SD = 0.41) from 21 secondary schools in Australia. Schools were randomised to receive either the six lesson computer-based Climate Schools program or their usual health classes, including drug education, over the year. The Climate Schools program was shown to increase knowledge of cannabis and psychostimulants and decrease pro-drug attitudes. In the short-term the program was effective in subduing the uptake and plateauing the frequency of ecstasy use, however there were no changes in meth/amphetamine use. In addition, females who received the program used cannabis significantly less frequently than students who received drug education as usual. Finally, the Climate Schools program was related to decreasing students' intentions to use meth/amphetamine and ecstasy in the future, however these effects did not last over time. These findings provide support for the use of a harm-minimisation approach and computer technology as an innovative platform for the delivery of prevention education for illicit drugs in schools. The current study indicated that teachers and students enjoyed the program and that it is feasible to extend the successful Climate Schools model to the prevention of other drugs, namely cannabis and psychostimulants. Australian and New Zealand Clinical Trials Registry ACTRN12613000492752.

A Cluster Randomized Controlled Trial Testing the Effectiveness of Houvast: A Strengths-Based Intervention for Homeless Young Adults

ERIC Educational Resources Information Center

Krabbenborg, Manon A. M.; Boersma, Sandra N.; van der Veld, William M.; van Hulst, Bente; Vollebergh, Wilma A. M.; Wolf, Judith R. L. M.

2017-01-01

Objective: To test the effectiveness of Houvast: a strengths-based intervention for homeless young adults. Method: A cluster randomized controlled trial was conducted with 10 Dutch shelter facilities randomly allocated to an intervention and a control group. Homeless young adults were interviewed when entering the facility and when care ended.…

The effect of AGN feedback on the X-ray morphologies of clusters: Simulations vs. observations

NASA Astrophysics Data System (ADS)

Chon, Gayoung; Puchwein, Ewald; Böhringer, Hans

2016-07-01

Clusters of galaxies probe the large-scale distribution of matter and are a useful tool to test the cosmological models by constraining cosmic structure growth and the expansion of the Universe. It is the scaling relations between mass observables and the true mass of a cluster through which we obtain the cosmological constraints by comparing to theoretical cluster mass functions. These scaling relations are, however, heavily influenced by cluster morphology. The presence of the slight tension in recent cosmological constraints on Ωm and σ8 based on the CMB and clusters has boosted the interests in looking for possible sources for the discrepancy. Therefore we study here the effect of active galactic nucleus (AGN) feedback as one of the major mechanisms modifying the cluster morphology influencing scaling relations. It is known that AGN feedback injects energies up to 1062 erg into the intracluster medium, controls the heating and cooling of a cluster, and re-distributes cold gas from the centre to outer radii. We have also learned that cluster simulations with AGN feedback can reproduce observed cluster properties, for example, the X-ray luminosity, temperature, and cooling rate at the centre better than without the AGN feedback. In this paper using cosmological hydrodynamical simulations we investigate how the AGN feedback changes the X-ray morphology of the simulated systems, and compare this to the observed Representative XMM-Newton Cluster Structure Survey (REXCESS) clusters. We apply two substructure measures, centre shifts (w) and power ratios (e.g. P3/P0), to characterise the cluster morphology, and find that our simulated clusters are more substructured than the observed clusters based on the values of w and P3/P0. We also show that the degree of this discrepancy is affected by the inclusion of AGN feedback. While the clusters simulated with the AGN feedback are in much better agreement with the REXCESS LX-T relation, they are also more substructured, which increases the tension with observations. When classified as non-relaxed or relaxed according to their w and P3/P0 values, we find that there are no relaxed clusters in the simulations with the AGN feedback. This suggests that not only global cluster properties, like LX and T, and radial profiles should be used to compare and to calibrate simulations with observations, but also substructure measures like centre shifts and power ratios. Finally, we discuss what changes in the simulations might ease the tension with observational constraints on these quantities.

Systematic review of universal resilience interventions targeting child and adolescent mental health in the school setting: review protocol.

PubMed

Dray, Julia; Bowman, Jenny; Wolfenden, Luke; Campbell, Elizabeth; Freund, Megan; Hodder, Rebecca; Wiggers, John

2015-12-29

The mental health of children and adolescents is a key area of health concern internationally. Previous empirical studies suggest that resilience may act as a protective mechanism towards the development of mental health problems. Resilience refers to the ability to employ a collection of protective factors to return to or maintain positive mental health following disadvantage or adversity. Schools represent a potential setting within which protective factors of all children and adolescents may be fostered through resilience-focussed interventions. Despite this potential, limited research has investigated the effectiveness of universal school-based resilience-focussed interventions on mental health outcomes in children and adolescents. The objective of the present review is to assess the effects of universal school-based resilience-focussed interventions, relative to a comparison group, on mental health outcomes in children and adolescents. Eligible studies will be randomised (including cluster-randomised) controlled trials of universal interventions explicitly described as resilience-focussed or comprising strategies to strengthen a minimum of three internal protective factors, targeting children aged 5 to 18 years, implemented within schools, and reporting a mental health outcome. Screening for studies will be conducted across six electronic databases: MEDLINE, PsycINFO, Educational Resources Information Center (ERIC), Excerpta Medica database (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Central Register of Controlled Trials (CENTRAL). Two reviewers will retrieve eligible articles, assess risk of bias, and extract data. Where studies are sufficiently homogenous and reported outcomes are amenable for pooled synthesis, meta-analysis will be performed. Narrative description will be used to synthesise trial outcome data where data cannot be combined or heterogeneity exists. This review will aid in building an evidence base for the effectiveness of universal school-based resilience-focussed interventions and in doing so provide an opportunity to better inform the development of interventions to potentially prevent mental health problems in child and adolescent populations. PROSPERO CRD42015025908.

A Gender Bias Habit-Breaking Intervention Led to Increased Hiring of Female Faculty in STEMM Departments.

PubMed

Devine, Patricia G; Forscher, Patrick S; Cox, William T L; Kaatz, Anna; Sheridan, Jennifer; Carnes, Molly

2017-11-01

Addressing the underrepresentation of women in science is a top priority for many institutions, but the majority of efforts to increase representation of women are neither evidence-based nor rigorously assessed. One exception is the gender bias habit-breaking intervention (Carnes et al., 2015), which, in a cluster-randomized trial involving all but two departmental clusters ( N = 92) in the 6 STEMM focused schools/colleges at the University of Wisconsin - Madison, led to increases in gender bias awareness and self-efficacy to promote gender equity in academic science departments. Following this initial success, the present study compares, in a preregistered analysis, hiring rates of new female faculty pre- and post-manipulation. Whereas the proportion of women hired by control departments remained stable over time, the proportion of women hired by intervention departments increased by an estimated 18 percentage points ( OR = 2.23, d OR = 0.34). Though the preregistered analysis did not achieve conventional levels of statistical significance ( p < 0.07), our study has a hard upper limit on statistical power, as the cluster-randomized trial has a maximum sample size of 92 departmental clusters. These patterns have undeniable practical significance for the advancement of women in science, and provide promising evidence that psychological interventions can facilitate gender equity and diversity.

Experimental control of a fluidic pinball using genetic programming

NASA Astrophysics Data System (ADS)

Raibaudo, Cedric; Zhong, Peng; Noack, Bernd R.; Martinuzzi, Robert J.

2017-11-01

The wake stabilization of a triangular cluster of three rotating cylinders was investigated in the present study. Experiments were performed at Reynolds number Re 6000, and compared with URANS-2D simulations at same flow conditions. 2D2C PIV measurements and constant temperature anemometry were used to characterize the flow without and with actuation. Open-loop actuation was first considered for the identification of particular control strategies. Machine learning control was also implemented for the experimental study. Linear genetic programming has been used for the optimization of open-loop parameters and closed-loop controllers. Considering a cost function J based on the fluctuations of the velocity measured by the hot-wire sensor, significant performances were achieved using the machine learning approach. The present work is supported by the senior author's (R. J. Martinuzzi) NSERC discovery Grant. C. Raibaudo acknowledges the financial support of the University of Calgary Eyes-High PDF program.

Newspaper coverage of suicide and initiation of suicide clusters in teenagers in the USA, 1988-96: a retrospective, population-based, case-control study.

PubMed

Gould, Madelyn S; Kleinman, Marjorie H; Lake, Alison M; Forman, Judith; Midle, Jennifer Bassett

2014-06-01

Public health and clinical efforts to prevent suicide clusters are seriously hampered by the unanswered question of why such outbreaks occur. We aimed to establish whether an environmental factor-newspaper reports of suicide-has a role in the emergence of suicide clusters. In this retrospective, population-based, case-control study, we identified suicide clusters in young people aged 13-20 years in the USA from 1988 to 1996 (preceding the advent of social media) using the time-space Scan statistic. For each cluster community, we selected two matched non-cluster control communities in which suicides of similarly aged youth occurred, from non-contiguous counties within the same state as the cluster. We examined newspapers within each cluster community for stories about suicide published in the days between the first and second suicides in the cluster. In non-cluster communities, we examined a matched length of time after the matched control suicide. We used a content-analysis procedure to code the characteristics of each story and compared newspaper stories about suicide published in case and control communities with mixed-effect regression analyses. We identified 53 suicide clusters, of which 48 were included in the media review. For one cluster we could identify only one appropriate control; therefore, 95 matched control communities were included. The mean number of news stories about suicidal individuals published after an index cluster suicide (7·42 [SD 10·02]) was significantly greater than the mean number of suicide stories published after a non-cluster suicide (5·14 [6.00]; p<0·0001). Several story characteristics, including front-page placement, headlines containing the word suicide or a description of the method used, and detailed descriptions of the suicidal individual and act, appeared more often in stories published after the index cluster suicides than after non-cluster suicides. Our identification of an association between newspaper reports about suicide (including specific story characteristics) and the initiation of teenage suicide clusters should provide an empirical basis to support efforts by mental health professionals, community officials, and the media to work together to identify and prevent the onset of suicide clusters. US National Institute of Mental Health and American Foundation for Suicide Prevention. Copyright © 2014 Elsevier Ltd. All rights reserved.

Galaxy clusters in the cosmic web

NASA Astrophysics Data System (ADS)

Acebrón, A.; Durret, F.; Martinet, N.; Adami, C.; Guennou, L.

2014-12-01

Simulations of large scale structure formation in the universe predict that matter is essentially distributed along filaments at the intersection of which lie galaxy clusters. We have analysed 9 clusters in the redshift range 0.4

K-means cluster analysis of tourist destination in special region of Yogyakarta using spatial approach and social network analysis (a case study: post of @explorejogja instagram account in 2016)

NASA Astrophysics Data System (ADS)

Iswandhani, N.; Muhajir, M.

2018-03-01

This research was conducted in Department of Statistics Islamic University of Indonesia. The data used are primary data obtained by post @explorejogja instagram account from January until December 2016. In the @explorejogja instagram account found many tourist destinations that can be visited by tourists both in the country and abroad, Therefore it is necessary to form a cluster of existing tourist destinations based on the number of likes from user instagram assumed as the most popular. The purpose of this research is to know the most popular distribution of tourist spot, the cluster formation of tourist destinations, and central popularity of tourist destinations based on @explorejogja instagram account in 2016. Statistical analysis used is descriptive statistics, k-means clustering, and social network analysis. The results of this research were obtained the top 10 most popular destinations in Yogyakarta, map of html-based tourist destination distribution consisting of 121 tourist destination points, formed 3 clusters each consisting of cluster 1 with 52 destinations, cluster 2 with 9 destinations and cluster 3 with 60 destinations, and Central popularity of tourist destinations in the special region of Yogyakarta by district.

Antenatal peer support workers and initiation of breast feeding: cluster randomised controlled trial.

PubMed

MacArthur, Christine; Jolly, Kate; Ingram, Lucy; Freemantle, Nick; Dennis, Cindy-Lee; Hamburger, Ros; Brown, Julia; Chambers, Jackie; Khan, Khalid

2009-01-30

To assess the effectiveness of an antenatal service using community based breastfeeding peer support workers on initiation of breast feeding. Cluster randomised controlled trial. Community antenatal clinics in one primary care trust in a multiethnic, deprived population. 66 antenatal clinics with 2511 pregnant women: 33 clinics including 1140 women were randomised to receive the peer support worker service and 33 clinics including 1371 women were randomised to receive standard care. An antenatal peer support worker service planned to comprise a minimum of two contacts with women to provide advice, information, and support from approximately 24 weeks' gestation within the antenatal clinic or at home. The trained peer support workers were of similar ethnic and sociodemographic backgrounds to their clinic population. Initiation of breast feeding obtained from computerised maternity records of the hospitals where women from the primary care trust delivered. The sample was multiethnic, with only 9.4% of women being white British, and 70% were in the lowest 10th for deprivation. Most of the contacts with peer support workers took place in the antenatal clinics. Data on initiation of breast feeding were obtained for 2398 of 2511 (95.5%) women (1083/1140 intervention and 1315/1371 controls). The groups did not differ for initiation of breast feeding: 69.0% (747/1083) in the intervention group and 68.1% (896/1315) in the control groups; cluster adjusted odds ratio 1.11 (95% confidence interval 0.87 to 1.43). Ethnicity, parity, and mode of delivery independently predicted initiation of breast feeding, but randomisation to the peer support worker service did not. A universal service for initiation of breast feeding using peer support workers provided within antenatal clinics serving a multiethnic, deprived population was ineffective in increasing initiation rates. Current Controlled Trials ISRCTN16126175.

Incorporating prototyping and iteration into intervention development: a case study of a dining hall-based intervention.

PubMed

McClain, Arianna D; Hekler, Eric B; Gardner, Christopher D

2013-01-01

Previous research from the fields of computer science and engineering highlight the importance of an iterative design process (IDP) to create more creative and effective solutions. This study describes IDP as a new method for developing health behavior interventions and evaluates the effectiveness of a dining hall-based intervention developed using IDP on college students' eating behavior and values. participants were 458 students (52.6% female, age = 19.6 ± 1.5 years [M ± SD]). The intervention was developed via an IDP parallel process. A cluster-randomized controlled study compared differences in eating behavior among students in 4 university dining halls (2 intervention, 2 control). The final intervention was a multicomponent, point-of-selection marketing campaign. Students in the intervention dining halls consumed significantly less junk food and high-fat meat and increased their perceived importance of eating a healthful diet relative to the control group. IDP may be valuable for the development of behavior change interventions.

University and student segmentation: multilevel latent-class analysis of students' attitudes towards research methods and statistics.

PubMed

Mutz, Rüdiger; Daniel, Hans-Dieter

2013-06-01

It is often claimed that psychology students' attitudes towards research methods and statistics affect course enrollment, persistence, achievement, and course climate. However, the inter-institutional variability has been widely neglected in the research on students' attitudes towards research methods and statistics, but it is important for didactic purposes (heterogeneity of the student population). The paper presents a scale based on findings of the social psychology of attitudes (polar and emotion-based concept) in conjunction with a method for capturing beginning university students' attitudes towards research methods and statistics and identifying the proportion of students having positive attitudes at the institutional level. The study based on a re-analysis of a nationwide survey in Germany in August 2000 of all psychology students that enrolled in fall 1999/2000 (N= 1,490) and N= 44 universities. Using multilevel latent-class analysis (MLLCA), the aim was to group students in different student attitude types and at the same time to obtain university segments based on the incidences of the different student attitude types. Four student latent clusters were found that can be ranked on a bipolar attitude dimension. Membership in a cluster was predicted by age, grade point average (GPA) on school-leaving exam, and personality traits. In addition, two university segments were found: universities with an average proportion of students with positive attitudes and universities with a high proportion of students with positive attitudes (excellent segment). As psychology students make up a very heterogeneous group, the use of multiple learning activities as opposed to the classical lecture course is required. © 2011 The British Psychological Society.

Einstein's Theory Fights off Challengers

NASA Astrophysics Data System (ADS)

2010-04-01

Two new and independent studies have put Einstein's General Theory of Relativity to the test like never before. These results, made using NASA's Chandra X-ray Observatory, show Einstein's theory is still the best game in town. Each team of scientists took advantage of extensive Chandra observations of galaxy clusters, the largest objects in the Universe bound together by gravity. One result undercuts a rival gravity model to General Relativity, while the other shows that Einstein's theory works over a vast range of times and distances across the cosmos. The first finding significantly weakens a competitor to General Relativity known as "f(R) gravity". "If General Relativity were the heavyweight boxing champion, this other theory was hoping to be the upstart contender," said Fabian Schmidt of the California Institute of Technology in Pasadena, who led the study. "Our work shows that the chances of its upsetting the champ are very slim." In recent years, physicists have turned their attention to competing theories to General Relativity as a possible explanation for the accelerated expansion of the universe. Currently, the most popular explanation for the acceleration is the so-called cosmological constant, which can be understood as energy that exists in empty space. This energy is referred to as dark energy to emphasize that it cannot be directly detected. In the f(R) theory, the cosmic acceleration comes not from an exotic form of energy but from a modification of the gravitational force. The modified force also affects the rate at which small enhancements of matter can grow over the eons to become massive clusters of galaxies, opening up the possibility of a sensitive test of the theory. Schmidt and colleagues used mass estimates of 49 galaxy clusters in the local universe from Chandra observations, and compared them with theoretical model predictions and studies of supernovas, the cosmic microwave background, and the large-scale distribution of galaxies. They found no evidence that gravity is different from General Relativity on scales larger than 130 million light years. This limit corresponds to a hundred-fold improvement on the bounds of the modified gravitational force's range that can be set without using the cluster data. "This is the strongest ever constraint set on an alternative to General Relativity on such large distance scales," said Schmidt. "Our results show that we can probe gravity stringently on cosmological scales by using observations of galaxy clusters." The reason for this dramatic improvement in constraints can be traced to the greatly enhanced gravitational forces acting in clusters as opposed to the universal background expansion of the universe. The cluster-growth technique also promises to be a good probe of other modified gravity scenarios, such as models motivated by higher-dimensional theories and string theory. A second, independent study also bolsters General Relativity by directly testing it across cosmological distances and times. Up until now, General Relativity had been verified only using experiments from laboratory to Solar System scales, leaving the door open to the possibility that General Relativity breaks down on much larger scales. To probe this question, a group at Stanford University compared Chandra observations of how rapidly galaxy clusters have grown over time to the predictions of General Relativity. The result is nearly complete agreement between observation and theory. "Einstein's theory succeeds again, this time in calculating how many massive clusters have formed under gravity's pull over the last five billion years," said David Rapetti of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University and SLAC National Accelerator Laboratory, who led the new study. "Excitingly and reassuringly, our results are the most robust consistency test of General Relativity yet carried out on cosmological scales." Rapetti and his colleagues based their results on a sample of 238 clusters detected across the whole sky by the now-defunct ROSAT X-ray telescope. These data were enhanced by detailed mass measurements for 71 distant clusters using Chandra, and 23 relatively nearby clusters using ROSAT, and combined with studies of supernovas, the cosmic microwave background, the distribution of galaxies and distance estimates to galaxy clusters. Galaxy clusters are important objects in the quest to understand the Universe as a whole. Because the observations of the masses of galaxy clusters are directly sensitive to the properties of gravity, they provide crucial information. Other techniques such as observations of supernovas or the distribution of galaxies measure cosmic distances, which depend only on the expansion rate of the universe. In contrast, the cluster technique used by Rapetti and his colleagues measure in addition the growth rate of the cosmic structure, as driven by gravity. "Cosmic acceleration represents a great challenge to our modern understanding of physics," said Rapetti's co-author Adam Mantz of NASA's Goddard Space Flight Center in Maryland. "Measurements of acceleration have highlighted how little we know about gravity at cosmic scales, but we're now starting to push back our ignorance." The paper by Fabian Schmidt was published in Physics Review D, Volume 80 in October 2009 and is co-authored by Alexey Vikhlinin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and Wayne Hu of the University of Chicago, Illinois. The paper by David Rapetti was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society and is co-authored by Mantz, Steve Allen of KIPAC at Stanford and Harald Ebeling of the Institute for Astronomy in Hawaii. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Core Collapse: The Race Between Stellar Evolution and Binary Heating

NASA Astrophysics Data System (ADS)

Converse, Joseph M.; Chandar, R.

2012-01-01

The dynamical formation of binary stars can dramatically affect the evolution of their host star clusters. In relatively small clusters (M < 6000 Msun) the most massive stars rapidly form binaries, heating the cluster and preventing any significant contraction of the core. The situation in much larger globular clusters (M 105 Msun) is quite different, with many showing collapsed cores, implying that binary formation did not affect them as severely as lower mass clusters. More massive clusters, however, should take longer to form their binaries, allowing stellar evolution more time to prevent the heating by causing the larger stars to die off. Here, we simulate the evolution of clusters between those of open and globular clusters in order to find at what size a star cluster is able to experience true core collapse. Our simulations make use of a new GPU-based computing cluster recently purchased at the University of Toledo. We also present some benchmarks of this new computational resource.

HUBBLE SPIES GLOBULAR CLUSTER IN NEIGHBORING GALAXY

NASA Technical Reports Server (NTRS)

2002-01-01

Hubble Space Telescope has captured a view of a globular cluster called G1, a large, bright ball of light in the center of the photograph consisting of at least 300,000 old stars. G1, also known as Mayall II, orbits the Andromeda galaxy (M31), the nearest major spiral galaxy to our Milky Way. Located 130,000 light-years from Andromeda's nucleus, G1 is the brightest globular cluster in the Local Group of galaxies. The Local Group consists of about 20 nearby galaxies, including the Milky Way. The crisp image is comparable to ground-based telescope views of similar clusters orbiting the Milky Way. The Andromeda cluster, however, is nearly 100 times farther away. A glimpse into the cluster's finer details allow astronomers to see its fainter helium-burning stars whose temperatures and brightnesses show that this cluster in Andromeda and the oldest Milky Way clusters have approximately the same age. These clusters probably were formed shortly after the beginning of the universe, providing astronomers with a record of the earliest era of galaxy formation. During the next two years, astronomers will use Hubble to study about 20 more globular clusters in Andromeda. The color picture was assembled from separate images taken in visible and near-infrared wavelengths taken in July of 1994. CREDIT: Michael Rich, Kenneth Mighell, and James D. Neill (Columbia University), and Wendy Freedman (Carnegie Observatories), and NASA Image files in GIF and JPEG format and captions may be accessed on Internet via anonymous ftp from oposite.stsci.edu in /pubinfo.

Kinematics of AWM and MKW Poor Clusters

NASA Astrophysics Data System (ADS)

Koranyi, Daniel M.; Geller, Margaret J.

2002-01-01

We have measured 1365 redshifts to a limiting magnitude of R~15.5 in 15 AWM/MKW clusters and have collected another 203 from the literature in MKW 4s, MKW 2, and MKW 2s. In AWM 7 we have extended the redshift sample to R~18 in the cluster center. We have identified 704 cluster members in 17 clusters; 201 are newly identified. We summarize the kinematics and distributions of the cluster galaxies and provide an initial discussion of substructure, mass and luminosity segregation, spectral segregation, velocity-dispersion profiles, and the relation of the central galaxy to global cluster properties. We compute optical mass estimates, which we compare with X-ray mass determinations from the literature. The clusters are in a variety of dynamical states, reflected in the three classes of behavior of the velocity-dispersion profile in the core: rising, falling, or flat/ambiguous. The velocity dispersion of the emission-line galaxy population significantly exceeds that of the absorption-line galaxies in almost all of the clusters, and the presence of emission-line galaxies at small projected radii suggests continuing infall of galaxies onto the clusters. The presence of a cD galaxy does not constrain the global cluster properties; these clusters are similar to other poor clusters that contain no cD. We use the similarity of the velocity-dispersion profiles at small radii and the cD-like galaxies' internal velocity dispersions to argue that cD formation is a local phenomenon. Our sample establishes an empirical observational baseline of poor clusters for comparison with simulations of similar systems. Observations reported in this paper were obtained at the Multiple Mirror Telescope Observatory, a facility operated jointly by the University of Arizona and the Smithsonian Institution; at the Whipple Observatory, a facility operated jointly by the Smithsonian Astrophysical Observatory and Harvard University; and at the WIYN Observatory, a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories.

Galaxy clusters and cold dark matter - A low-density unbiased universe?

NASA Technical Reports Server (NTRS)

Bahcall, Neta A.; Cen, Renyue

1992-01-01

Large-scale simulations of a universe dominated by cold dark matter (CDM) are tested against two fundamental properties of clusters of galaxies: the cluster mass function and the cluster correlation function. We find that standard biased CDM models are inconsistent with these observations for any bias parameter b. A low-density, low-bias CDM-type model, with or without a cosmological constant, appears to be consistent with both the cluster mass function and the cluster correlations. The low-density model agrees well with the observed correlation function of the Abell, Automatic Plate Measuring Facility (APM), and Edinburgh-Durham cluster catalogs. The model is in excellent agreement with the observed dependence of the correlation strength on cluster mean separation, reproducing the measured universal dimensionless cluster correlation. The low-density model is also consistent with other large-scale structure observations, including the APM angular galaxy-correlations, and for lambda = 1-Omega with the COBE results of the microwave background radiation fluctuations.

Cluster-based adaptive power control protocol using Hidden Markov Model for Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Vinutha, C. B.; Nalini, N.; Nagaraja, M.

2017-06-01

This paper presents strategies for an efficient and dynamic transmission power control technique, in order to reduce packet drop and hence energy consumption of power-hungry sensor nodes operated in highly non-linear channel conditions of Wireless Sensor Networks. Besides, we also focus to prolong network lifetime and scalability by designing cluster-based network structure. Specifically we consider weight-based clustering approach wherein, minimum significant node is chosen as Cluster Head (CH) which is computed stemmed from the factors distance, remaining residual battery power and received signal strength (RSS). Further, transmission power control schemes to fit into dynamic channel conditions are meticulously implemented using Hidden Markov Model (HMM) where probability transition matrix is formulated based on the observed RSS measurements. Typically, CH estimates initial transmission power of its cluster members (CMs) from RSS using HMM and broadcast this value to its CMs for initialising their power value. Further, if CH finds that there are variations in link quality and RSS of the CMs, it again re-computes and optimises the transmission power level of the nodes using HMM to avoid packet loss due noise interference. We have demonstrated our simulation results to prove that our technique efficiently controls the power levels of sensing nodes to save significant quantity of energy for different sized network.

ESA's XMM-Newton gains deep insights into the distant Universe

NASA Astrophysics Data System (ADS)

2003-07-01

First image from the XMM-LSS survey hi-res Size hi-res: 87 kb Credits: ESA First image from the XMM-LSS survey The first image from the XMM-LSS survey is actually a combination of fourteen separate 'pointings' of the space observatory. It represents a region of the sky eight times larger than the full Moon and contains around 25 clusters. The circles represent the sources previously known from the 1991 ROSAT All-Sky Survey. A computer programme zooms in on an interesting region hi-res Size hi-res: 86 kb Credits: ESA A computer programme zooms in on an interesting region A computer programme zooms in on an interesting region of the image and identifies the possible cluster. Each point on this graph represents a single X-ray photons detected by XMM-Newton. Most come from distant actie galaxies and the computer must perform a sophisticated, statistical computation to determine which X-ray come from clusters. Contour map of clusters hi-res Size hi-res: 139 kb Credits: ESA Contour map of clusters The computer programme transforms the XMM-Newton data into a contour map of the cluster's probable extent and superimposes it over the CFHT snapshot, allowing the individual galaxies in the cluster to be targeted for further observations with ESO's VLT, to measure its distance and locate the cluster in the universe. Unlike grains of sand on a beach, matter is not uniformly spread throughout the Universe. Instead, it is concentrated into galaxies like our own which themselves congregate into clusters. These clusters are 'strung' throughout the Universe in a web-like structure. Astronomers have studied this large-scale structure of the nearby Universe but have lacked the instruments to extend the search to the large volumes of the distant Universe. Thanks to its unrivalled sensitivity, in less than three hours, ESA's X-ray observatory XMM-Newton can see back about 7000 million years to a cosmological era when the Universe was about half its present size, and clusters of galaxies more tightly packed. Marguerite Pierre, CEA Saclay, France, with a European and Chilean team, used this ability to search for remote clusters of galaxies and map out their distribution. The work heralds a new era of studying the distant Universe. The optical identification of clusters shows only the galaxies themselves. However, X-rays show the gas in between the galaxies - which is where most of the matter in a cluster resides. This is like going from seeing a city at night, where you only see the lighted windows, to seeing it during the daytime, when you finally get to see the buildings themselves. Tracking down the clusters is a painstaking, multi-step process. In tandem with XMM-Newton, the team uses the four-metre Canada-France-Hawaii Telescope (CFHT), on Mauna Kea, Hawaii, to take an optical snapshot of the same region of space. A tailor-made computer programme combs the XMM-Newton data looking for concentrations of X-rays that suggest large, extended structures. These are the clusters and they represent only about 10% of the detected X-ray sources (the others are mostly distant active galaxies). When the program finds a cluster, it zooms in on that region and converts the XMM-Newton data into a contour map of X-ray intensity, which it then superimposes on the CFHT optical image. The astronomers use this to check if anything is visible within the X-ray emission. If it is, the work then shifts to one of the world's largest telescopes, the European Southern Observatory (ESO) Very Large Telescope where the astronomers identify the individual galaxies in the cluster and take 'redshift' measurements. These give a measurement of the cluster's distance. In this way, Pierre and colleagues are mapping the distribution of galaxy clusters of the distant Universe, for the first time in astronomy. "Galaxy clusters are the largest concentrations of matter in the Universe and XMM-Newton is extremely efficient at finding them," says Pierre. Although the task is still a work in progress, first results seem to confirm that the number of clusters 7000 million years ago is little different from that of today. This behaviour is predicted by models of the Universe that expand forever and drive the galaxy clusters further and further apart. Eventually, it will be possible for the team to use their results to determine whether the expansion of the Universe is accelerating, as indicated by some other recent observations, or decelerating, as traditionally thought. Note to Editors: This is a coordinated ESA/ESO release. The presented results have been obtained by the XMM-LSS consortium, led by Service d'Astrophysique du CEA (France) and consisting of Co-I institutes from the United Kingdom, Ireland, Denmark, The Netherlands, Belgium, France, Italy, Germany, Spain and Chile. The home page of the XMM-LSS project can be found at: http://vela.astro.ulg.ac.be/themes/spatial/xmm/LSS/index_e.html This work is based on two papers to be published in the professional astronomy journal, Astronomy and Astrophysics (The XMM-LSS survey:I. Scientific motivations, design and first results by Marguerite Pierre et al., astro-ph/0305191 and The XMM-LSS survey:II. First high redshift galaxy clusters: relaxed and collapsing systems by Ivan Valtchanov et al.,astro-ph/0305192). More about XMM-Newton XMM-Newton can detect more X-ray sources than any previous satellite and is helping to solve many cosmic mysteries of the violent Universe, from black holes to the formation of galaxies. It was launched on 10 December 1999, using an Ariane-5 rocket from French Guiana. It is expected to return data for a decade. XMM-Newton's high-tech design uses over 170 wafer-thin cylindrical mirrors spread over three telescopes. Its orbit takes it almost a third of the way to the Moon, so that astronomers can enjoy long, uninterrupted views of celestial objects.

A cluster randomised controlled trial to determine the effect of community mobilisation and advocacy on men’s use of violence in periurban South Africa: study protocol

PubMed Central

Christofides, Nicola J; Hatcher, Abigail M; Pino, Angelica; Rebombo, Dumisani; McBride, Ruari Santiago; Anderson, Althea; Peacock, Dean

2018-01-01

Objective This paper describes the design and methods of a cluster randomised controlled trial (C-RCT) to determine the effectiveness of a community mobilisation intervention that is designed to reduce the perpetration of violence against women (VAW). Methods and analysis A C-RCT of nine intervention and nine control clusters is being carried out in a periurban, semiformal settlement near Johannesburg, South Africa, between 2016 and 2018. A community mobilisation and advocacy intervention, called Sonke CHANGE is being implemented over 18 months. It comprises local advocacy and group activities to engage community members to challenge harmful gender norms and reduce VAW. The intervention is hypothesised to improve equitable masculinities, reduce alcohol use and ultimately, to reduce VAW. Intervention effectiveness will be determined through an audio computer-assisted self-interview questionnaire with behavioural measures among 2600 men aged between 18 and 40 years at baseline, 12 months and 24 months. The primary trial outcome is men’s use of physical and/or sexual VAW. Secondary outcomes include harmful alcohol use, gender attitudes, controlling behaviours, transactional sex and social cohesion. The main analysis will be intention-to-treat based on the randomisation of clusters. A qualitative process evaluation is being conducted alongside the C-RCT. Implementers and men participating in the intervention will be interviewed longitudinally over the period of intervention implementation and observations of the workshops and other intervention activities are being carried out. Ethics and dissemination Ethical approval was obtained from the University of the Witwatersrand Human Research Ethics Committee and procedures comply with ethical recommendations of the United Nations Multi-Country Study on Men and Violence. Dissemination of research findings will take place with local stakeholders and through peer-reviewed publications, with data available on request or after 5 years of trial completion. Trial registration number NCT02823288; Pre-result. PMID:29574438

Uptake of Home-Based HIV Testing, Linkage to Care, and Community Attitudes about ART in Rural KwaZulu-Natal, South Africa: Descriptive Results from the First Phase of the ANRS 12249 TasP Cluster-Randomised Trial

PubMed Central

Okesola, Nonhlanhla; Tanser, Frank; Thiebaut, Rodolphe; Rekacewicz, Claire; Newell, Marie-Louise

2016-01-01

Background The 2015 WHO recommendation of antiretroviral therapy (ART) for all immediately following HIV diagnosis is partially based on the anticipated impact on HIV incidence in the surrounding population. We investigated this approach in a cluster-randomised trial in a high HIV prevalence setting in rural KwaZulu-Natal. We present findings from the first phase of the trial and report on uptake of home-based HIV testing, linkage to care, uptake of ART, and community attitudes about ART. Methods and Findings Between 9 March 2012 and 22 May 2014, five clusters in the intervention arm (immediate ART offered to all HIV-positive adults) and five clusters in the control arm (ART offered according to national guidelines, i.e., CD4 count ≤ 350 cells/μl) contributed to the first phase of the trial. Households were visited every 6 mo. Following informed consent and administration of a study questionnaire, each resident adult (≥16 y) was asked for a finger-prick blood sample, which was used to estimate HIV prevalence, and offered a rapid HIV test using a serial HIV testing algorithm. All HIV-positive adults were referred to the trial clinic in their cluster. Those not linked to care 3 mo after identification were contacted by a linkage-to-care team. Study procedures were not blinded. In all, 12,894 adults were registered as eligible for participation (5,790 in intervention arm; 7,104 in control arm), of whom 9,927 (77.0%) were contacted at least once during household visits. HIV status was ever ascertained for a total of 8,233/9,927 (82.9%), including 2,569 ascertained as HIV-positive (942 tested HIV-positive and 1,627 reported a known HIV-positive status). Of the 1,177 HIV-positive individuals not previously in care and followed for at least 6 mo in the trial, 559 (47.5%) visited their cluster trial clinic within 6 mo. In the intervention arm, 89% (194/218) initiated ART within 3 mo of their first clinic visit. In the control arm, 42.3% (83/196) had a CD4 count ≤ 350 cells/μl at first visit, of whom 92.8% initiated ART within 3 mo. Regarding attitudes about ART, 93% (8,802/9,460) of participants agreed with the statement that they would want to start ART as soon as possible if HIV-positive. Estimated baseline HIV prevalence was 30.5% (2,028/6,656) (95% CI 25.0%, 37.0%). HIV prevalence, uptake of home-based HIV testing, linkage to care within 6 mo, and initiation of ART within 3 mo in those with CD4 count ≤ 350 cells/μl did not differ significantly between the intervention and control clusters. Selection bias related to noncontact could not be entirely excluded. Conclusions Home-based HIV testing was well received in this rural population, although men were less easily contactable at home; immediate ART was acceptable, with good viral suppression and retention. However, only about half of HIV-positive people accessed care within 6 mo of being identified, with nearly two-thirds accessing care by 12 mo. The observed delay in linkage to care would limit the individual and public health ART benefits of universal testing and treatment in this population. Trial registration ClinicalTrials.gov NCT01509508 PMID:27504637

Uptake of Home-Based HIV Testing, Linkage to Care, and Community Attitudes about ART in Rural KwaZulu-Natal, South Africa: Descriptive Results from the First Phase of the ANRS 12249 TasP Cluster-Randomised Trial.

PubMed

Iwuji, Collins C; Orne-Gliemann, Joanna; Larmarange, Joseph; Okesola, Nonhlanhla; Tanser, Frank; Thiebaut, Rodolphe; Rekacewicz, Claire; Newell, Marie-Louise; Dabis, Francois

2016-08-01

The 2015 WHO recommendation of antiretroviral therapy (ART) for all immediately following HIV diagnosis is partially based on the anticipated impact on HIV incidence in the surrounding population. We investigated this approach in a cluster-randomised trial in a high HIV prevalence setting in rural KwaZulu-Natal. We present findings from the first phase of the trial and report on uptake of home-based HIV testing, linkage to care, uptake of ART, and community attitudes about ART. Between 9 March 2012 and 22 May 2014, five clusters in the intervention arm (immediate ART offered to all HIV-positive adults) and five clusters in the control arm (ART offered according to national guidelines, i.e., CD4 count ≤ 350 cells/μl) contributed to the first phase of the trial. Households were visited every 6 mo. Following informed consent and administration of a study questionnaire, each resident adult (≥16 y) was asked for a finger-prick blood sample, which was used to estimate HIV prevalence, and offered a rapid HIV test using a serial HIV testing algorithm. All HIV-positive adults were referred to the trial clinic in their cluster. Those not linked to care 3 mo after identification were contacted by a linkage-to-care team. Study procedures were not blinded. In all, 12,894 adults were registered as eligible for participation (5,790 in intervention arm; 7,104 in control arm), of whom 9,927 (77.0%) were contacted at least once during household visits. HIV status was ever ascertained for a total of 8,233/9,927 (82.9%), including 2,569 ascertained as HIV-positive (942 tested HIV-positive and 1,627 reported a known HIV-positive status). Of the 1,177 HIV-positive individuals not previously in care and followed for at least 6 mo in the trial, 559 (47.5%) visited their cluster trial clinic within 6 mo. In the intervention arm, 89% (194/218) initiated ART within 3 mo of their first clinic visit. In the control arm, 42.3% (83/196) had a CD4 count ≤ 350 cells/μl at first visit, of whom 92.8% initiated ART within 3 mo. Regarding attitudes about ART, 93% (8,802/9,460) of participants agreed with the statement that they would want to start ART as soon as possible if HIV-positive. Estimated baseline HIV prevalence was 30.5% (2,028/6,656) (95% CI 25.0%, 37.0%). HIV prevalence, uptake of home-based HIV testing, linkage to care within 6 mo, and initiation of ART within 3 mo in those with CD4 count ≤ 350 cells/μl did not differ significantly between the intervention and control clusters. Selection bias related to noncontact could not be entirely excluded. Home-based HIV testing was well received in this rural population, although men were less easily contactable at home; immediate ART was acceptable, with good viral suppression and retention. However, only about half of HIV-positive people accessed care within 6 mo of being identified, with nearly two-thirds accessing care by 12 mo. The observed delay in linkage to care would limit the individual and public health ART benefits of universal testing and treatment in this population. ClinicalTrials.gov NCT01509508.

No Evidence for Multiple Stellar Populations in the Low-mass Galactic Globular Cluster E 3

NASA Astrophysics Data System (ADS)

Salinas, Ricardo; Strader, Jay

2015-08-01

Multiple stellar populations are a widespread phenomenon among Galactic globular clusters. Even though the origin of the enriched material from which new generations of stars are produced remains unclear, it is likely that self-enrichment will be feasible only in clusters massive enough to retain this enriched material. We searched for multiple populations in the low mass (M˜ 1.4× {10}4 {M}⊙ ) globular cluster E3, analyzing SOAR/Goodman multi-object spectroscopy centered on the blue cyanogen (CN) absorption features of 23 red giant branch stars. We find that the CN abundance does not present the typical bimodal behavior seen in clusters hosting multistellar populations, but rather a unimodal distribution that indicates the presence of a genuine single stellar population, or a level of enrichment much lower than in clusters that show evidence for two populations from high-resolution spectroscopy. E3 would be the first bona fide Galactic old globular cluster where no sign of self-enrichment is found. Based on observations obtained at the Southern Astrophysical Research (SOAR) Telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Probing the z > 6 Universe with the First Hubble Frontier Fields Cluster A2744

NASA Astrophysics Data System (ADS)

Atek, Hakim; Richard, Johan; Kneib, Jean-Paul; Clement, Benjamin; Egami, Eiichi; Ebeling, Harald; Jauzac, Mathilde; Jullo, Eric; Laporte, Nicolas; Limousin, Marceau; Natarajan, Priyamvada

2014-05-01

The Hubble Frontier Fields program combines the capabilities of the Hubble Space Telescope (HST) with the gravitational lensing of massive galaxy clusters to probe the distant universe to an unprecedented depth. Here, we present the results of the first combined HST and Spitzer observations of the cluster A-2744. We combine the full near-infrared data with ancillary optical images to search for gravitationally lensed high-redshift (z >~ 6) galaxies. We report the detection of 15 I 814 dropout candidates at z ~ 6-7 and one Y 105 dropout at z ~ 8 in a total survey area of 1.43 arcmin2 in the source plane. The predictions of our lens model also allow us to identify five multiply imaged systems lying at redshifts between z ~ 6 and z ~ 8. Thanks to constraints from the mass distribution in the cluster, we were able to estimate the effective survey volume corrected for completeness and magnification effects. This was in turn used to estimate the rest-frame ultraviolet luminosity function (LF) at z ~ 6-8. Our LF results are generally in agreement with the most recent blank field estimates, confirming the feasibility of surveys through lensing clusters. Although based on a shallower observations than what will be achieved in the final data set including the full Advanced Camera for Survey observations, the LF presented here goes down to M UV ~-18.5, corresponding to 0.2L sstarf at z ~ 7 with one identified object at M UV ~-15 thanks to the highly magnified survey areas. This early study forecasts the power of using massive galaxy clusters as cosmic telescopes and its complementarity to blank fields. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 13495 and 11689. Based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. This work utilizes gravitational lensing models produced by PIs Ebeling, Merten, and Zitrin, and Sharon funded as part of the HST Frontier Fields program conducted by STScI. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. The lens models were obtained from the Mikulski Archive for Space Telescopes (MAST).

Effects of the X:IT smoking intervention: a school-based cluster randomized trial.

PubMed

Andersen, Anette; Krølner, Rikker; Bast, Lotus Sofie; Thygesen, Lau Caspar; Due, Pernille

2015-12-01

Uptake of smoking in adolescence is still of major public health concern. Evaluations of school-based programmes for smoking prevention show mixed results. The aim of this study was to examine the effect of X:IT, a multi-component school-based programme to prevent adolescent smoking. Data from a Danish cluster randomized trial included 4041 year-7 students (mean age: 12.5) from 51 intervention and 43 control schools. Outcome measure 'current smoking' was dichotomized into smoking daily, weekly, monthly or more seldom vs do not smoke. Analyses were adjusted for baseline covariates: sex, family socioeconomic position (SEP), best friend's smoking and parental smoking. We performed multilevel, logistic regression analyses of available cases and intention-to-treat (ITT) analyses, replacing missing outcome values by multiple imputation. At baseline, 4.7% and 6.8% of the students at the intervention and the control schools smoked, respectively. After 1 year of the intervention, the prevalence was 7.9% and 10.7%, respectively. At follow-up, 553 students (13.7%) did not answer the question on smoking. Available case analyses: crude odds ratios (OR) for smoking at intervention schools compared with control schools: 0.65 (0.48-0.88) and adjusted: 0.70 (0.47-1.04). ITT analyses: crude OR for smoking at intervention schools compared with control schools: 0.67 (0.50-0.89) and adjusted: 0.61 (0.45-0.82). Students at intervention schools had a lower risk of smoking after a year of intervention in year 7. This multi-component intervention involving educational, parental and context-related intervention components seems to be efficient in lowering or postponing smoking uptake in Danish adolescents. © The Author 2015; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

Local bladder cancer clusters in southeastern Michigan accounting for risk factors, covariates and residential mobility.

PubMed

Jacquez, Geoffrey M; Shi, Chen; Meliker, Jaymie R

2015-01-01

In case control studies disease risk not explained by the significant risk factors is the unexplained risk. Considering unexplained risk for specific populations, places and times can reveal the signature of unidentified risk factors and risk factors not fully accounted for in the case-control study. This potentially can lead to new hypotheses regarding disease causation. Global, local and focused Q-statistics are applied to data from a population-based case-control study of 11 southeast Michigan counties. Analyses were conducted using both year- and age-based measures of time. The analyses were adjusted for arsenic exposure, education, smoking, family history of bladder cancer, occupational exposure to bladder cancer carcinogens, age, gender, and race. Significant global clustering of cases was not found. Such a finding would indicate large-scale clustering of cases relative to controls through time. However, highly significant local clusters were found in Ingham County near Lansing, in Oakland County, and in the City of Jackson, Michigan. The Jackson City cluster was observed in working-ages and is thus consistent with occupational causes. The Ingham County cluster persists over time, suggesting a broad-based geographically defined exposure. Focused clusters were found for 20 industrial sites engaged in manufacturing activities associated with known or suspected bladder cancer carcinogens. Set-based tests that adjusted for multiple testing were not significant, although local clusters persisted through time and temporal trends in probability of local tests were observed. Q analyses provide a powerful tool for unpacking unexplained disease risk from case-control studies. This is particularly useful when the effect of risk factors varies spatially, through time, or through both space and time. For bladder cancer in Michigan, the next step is to investigate causal hypotheses that may explain the excess bladder cancer risk localized to areas of Oakland and Ingham counties, and to the City of Jackson.

Cluster-specific small airway modeling for imaging-based CFD analysis of pulmonary air flow and particle deposition in COPD smokers

NASA Astrophysics Data System (ADS)

Haghighi, Babak; Choi, Jiwoong; Choi, Sanghun; Hoffman, Eric A.; Lin, Ching-Long

2017-11-01

Accurate modeling of small airway diameters in patients with chronic obstructive pulmonary disease (COPD) is a crucial step toward patient-specific CFD simulations of regional airflow and particle transport. We proposed to use computed tomography (CT) imaging-based cluster membership to identify structural characteristics of airways in each cluster and use them to develop cluster-specific airway diameter models. We analyzed 284 COPD smokers with airflow limitation, and 69 healthy controls. We used multiscale imaging-based cluster analysis (MICA) to classify smokers into 4 clusters. With representative cluster patients and healthy controls, we performed multiple regressions to quantify variation of airway diameters by generation as well as by cluster. The cluster 2 and 4 showed more diameter decrease as generation increases than other clusters. The cluster 4 had more rapid decreases of airway diameters in the upper lobes, while cluster 2 in the lower lobes. We then used these regression models to estimate airway diameters in CT unresolved regions to obtain pressure-volume hysteresis curves using a 1D resistance model. These 1D flow solutions can be used to provide the patient-specific boundary conditions for 3D CFD simulations in COPD patients. Support for this study was provided, in part, by NIH Grants U01-HL114494, R01-HL112986 and S10-RR022421.

PREFACE: 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"

NASA Astrophysics Data System (ADS)

Yamada, Taiichi; Kanada-En'yo, Yoshiko

2014-12-01

The 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3) was held at KGU Kannai Media Center, Kanto Gakuin University, Yokohama, Japan, from May 26 to 30, 2014. Yokohama is the second largest city in Japan, about 25 km southeast of Tokyo. The first workshop of the series was held in Strasbourg, France, in 2008 and the second one was in Brussels, Belgium, in 2010. The purpose of SOTANCP3 was to discuss the present status and future perspectives of the nuclear cluster physics. The following nine topics were selected in order to cover most of the scientific programme and highlight an area where new ideas have emerged over recent years: (1) Cluster structures and many-body correlations in stable and unstable nuclei (2) Clustering aspects of nuclear reactions and resonances (3) Alpha condensates and analogy with condensed matter approaches (4) Role of tensor force in cluster physics and ab initio approaches (5) Clustering in hypernuclei (6) Nuclear fission, superheavy nuclei, and cluster decay (7) Cluster physics and nuclear astrophysics (8) Clustering in nuclear matter and neutron stars (9) Clustering in hadron and atomic physics There were 122 participants, including 53 from 17 foreign countries. In addition to invited talks, we had many talks selected from contributed papers. There were plenary, parallel, and poster sessions. Poster contributions were also presented as four-minute talks in parallel sessions. This proceedings contains the papers presented in invited and selected talks together with those presented in poster sessions. We would like to express our gratitude to the members of the International Advisory Committee and those of the Organizing Committee for their efforts which made this workshop successful. In particular we would like to present our great thanks to Drs. Y. Funaki, W. Horiuchi, N. Itagaki, M. Kimura, T. Myo, and T. Yoshida. We would like also to thank the following organizations for their sponsors: RCNP (Research Center for Nuclear Physics, Osaka University), CNS (Center for Nuclear Study, University of Tokyo), JICFuS (Joint Institute for Computational Fundamental Science), and RIKEN (Nishina Center for Accelerator-Based Science, Institute of Physical and Chemical Research). This workshop was supported by Yokohama Convention & Visitors Bureau and Kanto Gakuin University. It remains to be announced that the next, the fourth in this series of SOTANCP workshops, SOTANCP4, will be held in Galveston, Texas, USA, in 2018.

Effectiveness and micro-costing of the KiVa school-based bullying prevention programme in Wales: study protocol for a pragmatic definitive parallel group cluster randomised controlled trial.

PubMed

Clarkson, Suzy; Axford, Nick; Berry, Vashti; Edwards, Rhiannon Tudor; Bjornstad, Gretchen; Wrigley, Zoe; Charles, Joanna; Hoare, Zoe; Ukoumunne, Obioha C; Matthews, Justin; Hutchings, Judy

2016-02-01

Bullying refers to verbal, physical or psychological aggression repeated over time that is intended to cause harm or distress to the victims who are unable to defend themselves. It is a key public health priority owing to its widespread prevalence in schools and harmful short- and long-term effects on victims' well-being. There is a need to strengthen the evidence base by testing innovative approaches to preventing bullying. KiVa is a school-based bullying prevention programme with universal and indicated elements and an emphasis on changing bystander behaviour. It achieved promising results in a large trial in Finland, and now requires testing in other countries. This paper describes the protocol for a cluster randomised controlled trial (RCT) of KiVa in Wales. The study uses a two-arm waitlist control pragmatic definitive parallel group cluster RCT design with an embedded process evaluation and calculation of unit cost. Participating schools will be randomised a using a 1:1 ratio to KiVa plus usual provision (intervention group) or usual provision only (control group). The trial has one primary outcome, child self-reported victimisation from bullying, dichotomised as 'victimised' (bullied at least twice a month in the last couple of months) versus 'not victimised'. Secondary outcomes are: bullying perpetration; aspects of child social and emotional well-being (including emotional problems, conduct, peer relations, prosocial behaviour); and school attendance. Follow-up is at 12 months post-baseline. Implementation fidelity is measured through teacher-completed lesson records and independent school-wide observation. A micro-costing analysis will determine the costs of implementing KiVa, including recurrent and non-recurrent unit costs. Factors related to the scalability of the programme will be examined in interviews with head teachers and focus groups with key stakeholders in the implementation of school-based bullying interventions. The results from this trial will provide evidence on whether the KiVa programme is transportable from Finland to Wales in terms of effectiveness and implementation. It will provide information about the costs of delivery and generate insights into factors related to the scalability of the programme. Current Controlled Trials ISRCTN23999021 Date 10-6-13.

Characteristics of airflow and particle deposition in COPD current smokers

NASA Astrophysics Data System (ADS)

Zou, Chunrui; Choi, Jiwoong; Haghighi, Babak; Choi, Sanghun; Hoffman, Eric A.; Lin, Ching-Long

2017-11-01

A recent imaging-based cluster analysis of computed tomography (CT) lung images in a chronic obstructive pulmonary disease (COPD) cohort identified four clusters, viz. disease sub-populations. Cluster 1 had relatively normal airway structures; Cluster 2 had wall thickening; Cluster 3 exhibited decreased wall thickness and luminal narrowing; Cluster 4 had a significant decrease of luminal diameter and a significant reduction of lung deformation, thus having relatively low pulmonary functions. To better understand the characteristics of airflow and particle deposition in these clusters, we performed computational fluid and particle dynamics analyses on representative cluster patients and healthy controls using CT-based airway models and subject-specific 3D-1D coupled boundary conditions. The results show that particle deposition in central airways of cluster 4 patients was noticeably increased especially with increasing particle size despite reduced vital capacity as compared to other clusters and healthy controls. This may be attributable in part to significant airway constriction in cluster 4. This study demonstrates the potential application of cluster-guided CFD analysis in disease populations. NIH Grants U01HL114494 and S10-RR022421, and FDA Grant U01FD005837.

Self-Assembled Superparamagnetic Iron Oxide Nanoclusters for Universal Cell Labeling and MRI

NASA Astrophysics Data System (ADS)

Chen, Shuzhen; Zhang, Jun; Jiang, Shengwei; Lin, Gan; Luo, Bing; Yao, Huan; Lin, Yuchun; He, Chengyong; Liu, Gang; Lin, Zhongning

2016-05-01

Superparamagnetic iron oxide (SPIO) nanoparticles have been widely used in a variety of biomedical applications, especially as contrast agents for magnetic resonance imaging (MRI) and cell labeling. In this study, SPIO nanoparticles were stabilized with amphiphilic low molecular weight polyethylenimine (PEI) in an aqueous phase to form monodispersed nanocomposites with a controlled clustering structure. The iron-based nanoclusters with a size of 115.3 ± 40.23 nm showed excellent performance on cellular uptake and cell labeling in different types of cells, moreover, which could be tracked by MRI with high sensitivity. The SPIO nanoclusters presented negligible cytotoxicity in various types of cells as detected using MTS, LDH, and flow cytometry assays. Significantly, we found that ferritin protein played an essential role in protecting stress from SPIO nanoclusters. Taken together, the self-assembly of SPIO nanoclusters with good magnetic properties provides a safe and efficient method for universal cell labeling with noninvasive MRI monitoring capability.

Cluster Dynamics: Laying the Foundation for Tailoring the Design of Cluster ASSE

DTIC Science & Technology

2016-02-25

UNIVERSITY 201 OLD MAIN UNIVERSITY PARK, PA 16802-1505 02/25/2016 Final Report DISTRIBUTION A: Distribution approved for public release. Air Force...5f.  WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) PENNSYLVANIA STATE UNIVERSITY 201 OLD MAIN UNIVERSITY PARK, PA 16802-1505 US 8

Role of isolated and clustered DNA damage and the post-irradiating repair process in the effects of heavy ion beam irradiation.

PubMed

Tokuyama, Yuka; Furusawa, Yoshiya; Ide, Hiroshi; Yasui, Akira; Terato, Hiroaki

2015-05-01

Clustered DNA damage is a specific type of DNA damage induced by ionizing radiation. Any type of ionizing radiation traverses the target DNA molecule as a beam, inducing damage along its track. Our previous study showed that clustered DNA damage yields decreased with increased linear energy transfer (LET), leading us to investigate the importance of clustered DNA damage in the biological effects of heavy ion beam radiation. In this study, we analyzed the yield of clustered base damage (comprising multiple base lesions) in cultured cells irradiated with various heavy ion beams, and investigated isolated base damage and the repair process in post-irradiation cultured cells. Chinese hamster ovary (CHO) cells were irradiated by carbon, silicon, argon and iron ion beams with LETs of 13, 55, 90 and 200 keV µm(-1), respectively. Agarose gel electrophoresis of the cells with enzymatic treatments indicated that clustered base damage yields decreased as the LET increased. The aldehyde reactive probe procedure showed that isolated base damage yields in the irradiated cells followed the same pattern. To analyze the cellular base damage process, clustered DNA damage repair was investigated using DNA repair mutant cells. DNA double-strand breaks accumulated in CHO mutant cells lacking Xrcc1 after irradiation, and the cell viability decreased. On the other hand, mouse embryonic fibroblast (Mef) cells lacking both Nth1 and Ogg1 became more resistant than the wild type Mef. Thus, clustered base damage seems to be involved in the expression of heavy ion beam biological effects via the repair process. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

The study designed by a committee: design of the Multisite Violence Prevention Project.

PubMed

Henry, David B; Farrell, Albert D

2004-01-01

This article describes the research design of the Multisite Violence Prevention Project (MVPP), organized and funded by the National Center for Injury Prevention and Control (NCIPC) at the Centers for Disease Control and Prevention (CDC). CDC's objectives, refined in the course of collaboration among investigators, were to evaluate the efficacy of universal and targeted interventions designed to produce change at the school level. The project's design was developed collaboratively, and is a 2 x 2 cluster-randomized true experimental design in which schools within four separate sites were assigned randomly to four conditions: (1) no-intervention control group, (2) universal intervention, (3) targeted intervention, and (4) combined universal and targeted interventions. A total of 37 schools are participating in this study with 8-12 schools per site. The impact of the interventions on two successive cohorts of sixth-grade students will be assessed based on multiple waves of data from multiple sources of information, including teachers, students, parents, and archival data. The nesting of students within teachers, families, schools and sites created a number of challenges for designing and implementing the study. The final design represents both resolution and compromise on a number of creative tensions existing in large-scale prevention trials, including tensions between cost and statistical power, and between internal and external validity. Strengths and limitations of the final design are discussed.

The Study Designed by a Committee

PubMed Central

Henry, David B.; Farrell, Albert D.

2009-01-01

This article describes the research design of the Multisite Violence Prevention Project (MVPP), organized and funded by the National Center for Injury Prevention and Control (NCIPC) at the Centers for Disease Control and Prevention (CDC). CDC's objectives, refined in the course of collaboration among investigators, were to evaluate the efficacy of universal and targeted interventions designed to produce change at the school level. The project's design was developed collaboratively, and is a 2 × 2 cluster-randomized true experimental design in which schools within four separate sites were assigned randomly to four conditions: (1) no-intervention control group, (2) universal intervention, (3) targeted intervention, and (4) combined universal and targeted interventions. A total of 37 schools are participating in this study with 8–12 schools per site. The impact of the interventions on two successive cohorts of sixth-grade students will be assessed based on multiple waves of data from multiple sources of information, including teachers, students, parents, and archival data. The nesting of students within teachers, families, schools and sites created a number of challenges for designing and implementing the study. The final design represents both resolution and compromise on a number of creative tensions existing in large-scale prevention trials, including tensions between cost and statistical power, and between internal and external validity. Strengths and limitations of the final design are discussed. PMID:14732183

Has ESA's XMM-Newton cast doubt over dark energy?

NASA Astrophysics Data System (ADS)

2003-12-01

Galaxy cluster RXJ0847 hi-res Size hi-res: 100k Galaxy cluster RXJ0847 The fuzzy object at the centre of the frame is one of the galaxy clusters observed by XMM-Newton in its investigation of the distant Universe. The cluster, designated RXJ0847.2+3449, is about 7 000 million light years away, so we see it here as it was 7 000 million years ago, when the Universe was only about half of its present age. This cluster is made up of several dozen galaxies. Observations of eight distant clusters of galaxies, the furthest of which is around 10 thousand million light years away, were studied by an international group of astronomers led by David Lumb of ESA's Space Research and Technology Centre (ESTEC) in the Netherlands. They compared these clusters to those found in the nearby Universe. This study was conducted as part of the larger XMM-Newton Omega Project, which investigates the density of matter in the Universe under the lead of Jim Bartlett of the College de France. Clusters of galaxies are prodigious emitters of X-rays because they contain a large quantity of high-temperature gas. This gas surrounds galaxies in the same way as steam surrounds people in a sauna. By measuring the quantity and energy of X-rays from a cluster, astronomers can work out both the temperature of the cluster gas and also the mass of the cluster. Theoretically, in a Universe where the density of matter is high, clusters of galaxies would continue to grow with time and so, on average, should contain more mass now than in the past. Most astronomers believe that we live in a low-density Universe in which a mysterious substance known as 'dark energy' accounts for 70% of the content of the cosmos and, therefore, pervades everything. In this scenario, clusters of galaxies should stop growing early in the history of the Universe and look virtually indistinguishable from those of today. In a paper soon to be published by the European journal Astronomy and Astrophysics, astronomers from the XMM-Newton Omega Project present results showing that clusters of galaxies in the distant Universe are not like those of today. They seem to give out more X-rays than today. So clearly, clusters of galaxies have changed their appearance with time. In an accompanying paper, Alain Blanchard of the Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées and his team use the results to calculate how the abundance of galaxy clusters changes with time. Blanchard says, "There were fewer galaxy clusters in the past." Such a result indicates that the Universe must be a high-density environment, in clear contradiction to the 'concordance model,' which postulates a Universe with up to 70% dark energy and a very low density of matter. Blanchard knows that this conclusion will be highly controversial, saying, "To account for these results you have to have a lot of matter in the Universe and that leaves little room for dark energy." To reconcile the new XMM-Newton observations with the concordance models, astronomers would have to admit a fundamental gap in their knowledge about the behaviour of the clusters and, possibly, of the galaxies within them. For instance, galaxies in the faraway clusters would have to be injecting more energy into their surrounding gas than is currently understood. That process should then gradually taper off as the cluster and the galaxies within it grow older. No matter which way the results are interpreted, XMM-Newton has given astronomers a new insight into the Universe and a new mystery to puzzle over. As for the possibility that the XMM-Newton results are simply wrong, they are in the process of being confirmed by other X-ray observations. Should these return the same answer, we might have to rethink our understanding of the Universe. Notes for editors The two papers, The XMM-Newton Omega Project: I. The X-ray Luminosity-Temperature Relationship at z>0.4 by D.H. Lumb et al. and The XMM-Newton Omega Project: II. Cosmological implications from the high redshift L-T relation of X-ray clusters by S.C. Vauclair, A. Blanchard et al. will be published shortly in Astronomy and Astrophysics. The contents of the Universe The content of the Universe is widely thought to consist of three types of substance: normal matter, dark matter and dark energy. Normal matter consists of the atoms that make up stars, planets, human beings and every other visible object in the Universe. As humbling as it sounds, normal matter almost certainly accounts for a small proportion of the Universe, somewhere between 1% and 10%. The more astronomers observed the Universe, the more matter they needed to find to explain it all. This matter could not be made of normal atoms, however, otherwise there would be more stars and galaxies to be seen. Instead, they coined the term dark matter for this peculiar substance precisely because it escapes our detection. At the same time, physicists trying to further the understanding of the forces of nature were starting to believe that new and exotic particles of matter must be abundant in the Universe. These would hardly ever interact with normal matter and many now believe that these particles are the dark matter. At the present time, even though many experiments are underway to detect dark matter particles, none have been successful. Nevertheless, astronomers still believe that somewhere between 30% and 99% of the Universe may consist of dark matter. Dark energy is the latest addition to the contents of the Universe. Originally, Albert Einstein introduced the idea of an all-pervading 'cosmic energy' before he knew that the Universe is expanding. The expanding Universe did not need a 'cosmological constant' as Einstein had called his energy. However, in the 1990s observations of exploding stars in the distant Universe suggested that the Universe was not just expanding but accelerating as well. The only way to explain this was to reintroduce Einstein's cosmic energy in a slightly altered form, called dark energy. No one knows what the dark energy might be. In the currently popular 'concordance model' of the Universe, 70% of the cosmos is thought to be dark energy, 25% dark matter and 5% normal matter. XMM-Newton XMM-Newton can detect more X-ray sources than any previous satellite and is helping to solve many cosmic mysteries of the violent Universe, from black holes to the formation of galaxies. It was launched on 10 December 1999, using an Ariane-5 rocket from French Guiana. It is expected to return data for a decade. XMM-Newton's high-tech design uses over 170 wafer-thin cylindrical mirrors spread over three telescopes. Its orbit takes it almost a third of the way to the Moon, so that astronomers can enjoy long, uninterrupted views of celestial objects. Image caption The fuzzy object at the centre of the frame is one of the galaxy clusters observed by XMM-Newton in its investigation of the distant Universe. The cluster, designated RXJ0847.2+3449, is about 7 000 million light years away, so we see it here as it was 7 000 million years ago, when the Universe was only about half of its present age. This cluster is made up of several dozen galaxies. Credits: ESA

Clusters and the new economics of competition.

PubMed

Porter, M E

1998-01-01

Economic geography in an era of global competition poses a paradox. In theory, location should no longer be a source of competitive advantage. Open global markets, rapid transportation, and high-speed communications should allow any company to source any thing from any place at any time. But in practice, Michael Porter demonstrates, location remains central to competition. Today's economic map of the world is characterized by what Porter calls clusters: critical masses in one place of linked industries and institutions--from suppliers to universities to government agencies--that enjoy unusual competitive success in a particular field. The most famous example are found in Silicon Valley and Hollywood, but clusters dot the world's landscape. Porter explains how clusters affect competition in three broad ways: first, by increasing the productivity of companies based in the area; second, by driving the direction and pace of innovation; and third, by stimulating the formation of new businesses within the cluster. Geographic, cultural, and institutional proximity provides companies with special access, closer relationships, better information, powerful incentives, and other advantages that are difficult to tap from a distance. The more complex, knowledge-based, and dynamic the world economy becomes, the more this is true. Competitive advantage lies increasingly in local things--knowledge, relationships, and motivation--that distant rivals cannot replicate. Porter challenges the conventional wisdom about how companies should be configured, how institutions such as universities can contribute to competitive success, and how governments can promote economic development and prosperity.

A quasi-static approach to structure formation in black hole universes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durk, Jessie; Clifton, Timothy, E-mail: j.durk@qmul.ac.uk, E-mail: t.clifton@qmul.ac.uk

Motivated by the existence of hierarchies of structure in the Universe, we present four new families of exact initial data for inhomogeneous cosmological models at their maximum of expansion. These data generalise existing black hole lattice models to situations that contain clusters of masses, and hence allow the consequences of cosmological structures to be considered in a well-defined and non-perturbative fashion. The degree of clustering is controlled by a parameter λ, in such a way that for λ ∼ 0 or 1 we have very tightly clustered masses, whilst for λ ∼ 0.5 all masses are separated by cosmological distancemore » scales. We study the consequences of structure formation on the total net mass in each of our clusters, as well as calculating the cosmological consequences of the interaction energies both within and between clusters. The locations of the shared horizons that appear around groups of black holes, when they are brought sufficiently close together, are also identified and studied. We find that clustering can have surprisingly large effects on the scale of the cosmology, with models that contain thousands of black holes sometimes being as little as 30% of the size of comparable Friedmann models with the same total proper mass. This deficit is comparable to what might be expected to occur from neglecting gravitational interaction energies in Friedmann cosmology, and suggests that these quantities may have a significant influence on the properties of the large-scale cosmology.« less

Equilibrium Phase Behavior of a Continuous-Space Microphase Former.

PubMed

Zhuang, Yuan; Zhang, Kai; Charbonneau, Patrick

2016-03-04

Periodic microphases universally emerge in systems for which short-range interparticle attraction is frustrated by long-range repulsion. The morphological richness of these phases makes them desirable material targets, but our relatively coarse understanding of even simple models hinders controlling their assembly. We report here the solution of the equilibrium phase behavior of a microscopic microphase former through specialized Monte Carlo simulations. The results for cluster crystal, cylindrical, double gyroid, and lamellar ordering qualitatively agree with a Landau-type free energy description and reveal the nontrivial interplay between cluster, gel, and microphase formation.

Theory-based behavioral intervention increases self-reported physical activity in South African men: a cluster-randomized controlled trial.

PubMed

Jemmott, John B; Jemmott, Loretta S; Ngwane, Zolani; Zhang, Jingwen; Heeren, G Anita; Icard, Larry D; O'Leary, Ann; Mtose, Xoliswa; Teitelman, Anne; Carty, Craig

2014-07-01

To determine whether a health-promotion intervention increases South African men's adherence to physical-activity guidelines. We utilized a cluster-randomized controlled trial design. Eligible clusters, residential neighborhoods near East London, South Africa, were matched in pairs. Within randomly selected pairs, neighborhoods were randomized to theory-based, culturally congruent health-promotion intervention encouraging physical activity or attention-matched HIV/STI risk-reduction control intervention. Men residing in the neighborhoods and reporting coitus in the previous 3 months were eligible. Primary outcome was self-reported individual-level adherence to physical-activity guidelines averaged over 6-month and 12-month post-intervention assessments. Data were collected in 2007-2010. Data collectors, but not facilitators or participants, were blind to group assignment. Primary outcome intention-to-treat analysis included 22 of 22 clusters and 537 of 572 men in the health-promotion intervention and 22 of 22 clusters and 569 of 609 men in the attention-control intervention. Model-estimated probability of meeting physical-activity guidelines was 51.0% in the health-promotion intervention and 44.7% in attention-matched control (OR=1.34; 95% CI, 1.09-1.63), adjusting for baseline prevalence and clustering from 44 neighborhoods. A theory-based culturally congruent intervention increased South African men's self-reported physical activity, a key contributor to deaths from non-communicable diseases in South Africa. ClinicalTrials.gov Identifier: NCT01490359. Copyright © 2014 Elsevier Inc. All rights reserved.

Buckets, Clusters and Dienst

NASA Technical Reports Server (NTRS)

Nelson, Michael L.; Maly, Kurt; Shen, Stewart N. T.

1997-01-01

In this paper we describe NCSTRL+, a unified, canonical digital library for scientific and technical information (STI). NCSTRL+ is based on the Networked Computer Science Technical Report Library (NCSTRL), a World Wide Web (WWW) accessible digital library (DL) that provides access to over 80 university departments and laboratories. NCSTRL+ implements two new technologies: cluster functionality and publishing "buckets." We have extended the Dienst protocol, the protocol underlying NCSTRL, to provide the ability to "cluster" independent collections into a logically centralized digital library based upon subject category classification, type of organization, and genres of material. The concept of "buckets" provides a mechanism for publishing and managing logically linked entities with multiple data formats. The NCSTRL+ prototype DL contains the holdings of NCSTRL and the NASA Technical Report Server (NTRS). The prototype demonstrates the feasibility of publishing into a multi-cluster DL, searching across clusters, and storing and presenting buckets of information. We show that the overhead for these additional capabilities is minimal to both the author and the user when compared to the equivalent process within NCSTRL.

Interdisciplinary model of care (RADICALS) for early detection and management of chronic obstructive pulmonary disease (COPD) in Australian primary care: study protocol for a cluster randomised controlled trial.

PubMed

Liang, Jenifer; Abramson, Michael J; Zwar, Nicholas; Russell, Grant; Holland, Anne E; Bonevski, Billie; Mahal, Ajay; Hecke, Benjamin van; Phillips, Kirsten; Eustace, Paula; Paul, Eldho; Petrie, Kate; Wilson, Sally; George, Johnson

2017-09-18

Up to half of all smokers develop clinically significant chronic obstructive pulmonary disease (COPD). Gaps exist in the implementation and uptake of evidence-based guidelines for managing COPD in primary care. We describe the methodology of a cluster randomised controlled trial (cRCT) evaluating the efficacy and cost-effectiveness of an interdisciplinary model of care aimed at reducing the burden of smoking and COPD in Australian primary care settings. A cRCT is being undertaken to evaluate an interdisciplinary model of care (RADICALS - Review of Airway Dysfunction and Interdisciplinary Community-based care of Adult Long-term Smokers). General practice clinics across Melbourne, Australia, are identified and randomised to the intervention group (RADICALS) or usual care. Patients who are current or ex-smokers, of at least 10 pack years, including those with an existing diagnosis of COPD, are being recruited to identify 280 participants with a spirometry-confirmed diagnosis of COPD. Handheld lung function devices are being used to facilitate case-finding. RADICALS includes individualised smoking cessation support, home-based pulmonary rehabilitation and home medicines review. Patients at control group sites receive usual care and Quitline referral, as appropriate. Follow-ups occur at 6 and 12 months from baseline to assess changes in quality of life, abstinence rates, health resource utilisation, symptom severity and lung function. The primary outcome is change in St George's Respiratory Questionnaire score of patients with COPD at 6 months from baseline. This project has been approved by the Monash University Human Research Ethics Committee and La Trobe University Human Ethics Committee (CF14/1018 - 2014000433). Results of the study will be disseminated in peer-reviewed journals and research conferences. If the intervention is successful, the RADICALS programme could potentially be integrated into general practices across Australia and sustained over time. ACTRN12614001155684; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

DIMM-SC: a Dirichlet mixture model for clustering droplet-based single cell transcriptomic data.

PubMed

Sun, Zhe; Wang, Ting; Deng, Ke; Wang, Xiao-Feng; Lafyatis, Robert; Ding, Ying; Hu, Ming; Chen, Wei

2018-01-01

Single cell transcriptome sequencing (scRNA-Seq) has become a revolutionary tool to study cellular and molecular processes at single cell resolution. Among existing technologies, the recently developed droplet-based platform enables efficient parallel processing of thousands of single cells with direct counting of transcript copies using Unique Molecular Identifier (UMI). Despite the technology advances, statistical methods and computational tools are still lacking for analyzing droplet-based scRNA-Seq data. Particularly, model-based approaches for clustering large-scale single cell transcriptomic data are still under-explored. We developed DIMM-SC, a Dirichlet Mixture Model for clustering droplet-based Single Cell transcriptomic data. This approach explicitly models UMI count data from scRNA-Seq experiments and characterizes variations across different cell clusters via a Dirichlet mixture prior. We performed comprehensive simulations to evaluate DIMM-SC and compared it with existing clustering methods such as K-means, CellTree and Seurat. In addition, we analyzed public scRNA-Seq datasets with known cluster labels and in-house scRNA-Seq datasets from a study of systemic sclerosis with prior biological knowledge to benchmark and validate DIMM-SC. Both simulation studies and real data applications demonstrated that overall, DIMM-SC achieves substantially improved clustering accuracy and much lower clustering variability compared to other existing clustering methods. More importantly, as a model-based approach, DIMM-SC is able to quantify the clustering uncertainty for each single cell, facilitating rigorous statistical inference and biological interpretations, which are typically unavailable from existing clustering methods. DIMM-SC has been implemented in a user-friendly R package with a detailed tutorial available on www.pitt.edu/∼wec47/singlecell.html. wei.chen@chp.edu or hum@ccf.org. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

The properties of small Ag clusters bound to DNA bases.

PubMed

Soto-Verdugo, Víctor; Metiu, Horia; Gwinn, Elisabeth

2010-05-21

We study the binding of neutral silver clusters, Ag(n) (n=1-6), to the DNA bases adenine (A), cytosine (C), guanine (G), and thymine (T) and the absorption spectra of the silver cluster-base complexes. Using density functional theory (DFT), we find that the clusters prefer to bind to the doubly bonded ring nitrogens and that binding to T is generally much weaker than to C, G, and A. Ag(3) and Ag(4) make the stronger bonds. Bader charge analysis indicates a mild electron transfer from the base to the clusters for all bases, except T. The donor bases (C, G, and A) bind to the sites on the cluster where the lowest unoccupied molecular orbital has a pronounced protrusion. The site where cluster binds to the base is controlled by the shape of the higher occupied states of the base. Time-dependent DFT calculations show that different base-cluster isomers may have very different absorption spectra. In particular, we find new excitations in base-cluster molecules, at energies well below those of the isolated components, and with strengths that depend strongly on the orientations of planar clusters with respect to the base planes. Our results suggest that geometric constraints on binding, imposed by designed DNA structures, may be a feasible route to engineering the selection of specific cluster-base assemblies.

Emergence of clusters of CRF02_AG and B human immunodeficiency viral strains among men having sex with men exhibiting HIV primary infection in southeastern France.

PubMed

Tamalet, Catherine; Ravaux, Isabelle; Moreau, Jacques; Brégigeon, Sylvie; Tourres, Christian; Richet, Hervé; Abat, Cedric; Colson, Philippe

2015-08-01

The number of new HIV diagnoses is increasing in the western world and transmission clusters have been recently identified among men having sex with men despite Highly Active Antiretroviral Therapy efficacy. The objective of this study was to assess temporal trends, epidemiological, clinical and virological characteristics of primary HIV infections. A retrospective analysis of 79 patients presenting primary HIV infections from 2005 to 2012 was performed in Marseille University Hospitals, southeastern France. Clinical, epidemiological and immunovirological data including phylogeny based on the polymerase gene were collected. 65 males and 14 females were enrolled. The main transmission route was homosexual contact (60.8%). Patients were mostly infected with subtype B (73.4%) and CRF02_AG (21.5%) HIV-1 strains. An increase in the annual number of HIV seroconversions among new HIV diagnoses from 5% in 2005 to 11.2% in 2012 (P = 0.06) and of the proportion of CRF02_AG HIV strains among primary HIV infections in 2011-2012 as compared to 2005-2010 (P = 0.055) was observed. Phylogenetic analysis revealed four transmission clusters including three transmission clusters among men having sex with men: two large clusters of nine CRF02_AG, six B HIV strains; and one small cluster of three B HIV strains. Clusters involved more frequently men (P = 0.01) belonging to caucasian ethicity (P = 0.05), with a higher HIV RNA load at inclusion (P = 0.03). These data highlight the importance of improving epidemiological surveillance and of implementing suitable prevention strategies to control the spread of HIV transmission among men having sex with men. © 2015 Wiley Periodicals, Inc.

Collaboration patterns in the German political science co-authorship network.

PubMed

Leifeld, Philip; Wankmüller, Sandra; Berger, Valentin T Z; Ingold, Karin; Steiner, Christiane

2017-01-01

Research on social processes in the production of scientific output suggests that the collective research agenda of a discipline is influenced by its structural features, such as "invisible colleges" or "groups of collaborators" as well as academic "stars" that are embedded in, or connect, these research groups. Based on an encompassing dataset that takes into account multiple publication types including journals and chapters in edited volumes, we analyze the complete co-authorship network of all 1,339 researchers in German political science. Through the use of consensus graph clustering techniques and descriptive centrality measures, we identify the ten largest research clusters, their research topics, and the most central researchers who act as bridges and connect these clusters. We also aggregate the findings at the level of research organizations and consider the inter-university co-authorship network. The findings indicate that German political science is structured by multiple overlapping research clusters with a dominance of the subfields of international relations, comparative politics and political sociology. A small set of well-connected universities takes leading roles in these informal research groups.

Collaboration patterns in the German political science co-authorship network

PubMed Central

Wankmüller, Sandra; Berger, Valentin T. Z.; Ingold, Karin; Steiner, Christiane

2017-01-01

Research on social processes in the production of scientific output suggests that the collective research agenda of a discipline is influenced by its structural features, such as “invisible colleges” or “groups of collaborators” as well as academic “stars” that are embedded in, or connect, these research groups. Based on an encompassing dataset that takes into account multiple publication types including journals and chapters in edited volumes, we analyze the complete co-authorship network of all 1,339 researchers in German political science. Through the use of consensus graph clustering techniques and descriptive centrality measures, we identify the ten largest research clusters, their research topics, and the most central researchers who act as bridges and connect these clusters. We also aggregate the findings at the level of research organizations and consider the inter-university co-authorship network. The findings indicate that German political science is structured by multiple overlapping research clusters with a dominance of the subfields of international relations, comparative politics and political sociology. A small set of well-connected universities takes leading roles in these informal research groups. PMID:28388621

A cluster-randomized trial of a college health center-based alcohol and sexual violence intervention (GIFTSS): Design, rationale, and baseline sample.

PubMed

Abebe, Kaleab Z; Jones, Kelley A; Rofey, Dana; McCauley, Heather L; Clark, Duncan B; Dick, Rebecca; Gmelin, Theresa; Talis, Janine; Anderson, Jocelyn; Chugani, Carla; Algarroba, Gabriela; Antonio, Ashley; Bee, Courtney; Edwards, Clare; Lethihet, Nadia; Macak, Justin; Paley, Joshua; Torres, Irving; Van Dusen, Courtney; Miller, Elizabeth

2018-02-01

Sexual violence (SV) on college campuses is common, especially alcohol-related SV. This is a 2-arm cluster randomized controlled trial to test a brief intervention to reduce risk for alcohol-related sexual violence (SV) among students receiving care from college health centers (CHCs). Intervention CHC staff are trained to deliver universal SV education to all students seeking care, to facilitate patient and provider comfort in discussing SV and related abusive experiences (including the role of alcohol). Control sites provide participants with information about drinking responsibly. Across 28 participating campuses (12 randomized to intervention and 16 to control), 2292 students seeking care at CHCs complete surveys prior to their appointment (baseline), immediately after (exit), 4months later (T2) and one year later (T3). The primary outcome is change in recognition of SV and sexual risk. Among those reporting SV exposure at baseline, changes in SV victimization, disclosure, and use of SV services are additional outcomes. Intervention effects will be assessed using generalized linear mixed models that account for clustering of repeated observations both within CHCs and within students. Slightly more than half of the participating colleges have undergraduate enrollment of ≥3000 students; two-thirds are public and almost half are urban. Among participants there were relatively more Asian (10 v 1%) and Black/African American (13 v 7%) and fewer White (58 v 74%) participants in the intervention compared to control. This study will offer the first formal assessment for SV prevention in the CHC setting. Clinical Trials #: NCT02355470. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Searching for Primordial Antimatter

NASA Astrophysics Data System (ADS)

2008-10-01

Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - leftover from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult. Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2. According to the Big Bang model, the Universe was awash in particles of both matter and antimatter shortly after the Big Bang. Most of this material annihilated, but because there was slightly more matter than antimatter - less than one part per billion - only matter was left behind, at least in the local Universe. Trace amounts of antimatter are believed to be produced by powerful phenomena such as relativistic jets powered by black holes and pulsars, but no evidence has yet been found for antimatter remaining from the infant Universe. How could any primordial antimatter have survived? Just after the Big Bang there was believed to be an extraordinary period, called inflation, when the Universe expanded exponentially in just a fraction of a second. "If clumps of matter and antimatter existed next to each other before inflation, they may now be separated by more than the scale of the observable Universe, so we would never see them meet," said Gary Steigman of The Ohio State University, who conducted the study. "But, they might be separated on smaller scales, such as those of superclusters or clusters, which is a much more interesting possibility." X-rayChandra X-ray Image In that case, collisions between two galaxy clusters, the largest gravitationally-bound structures in the Universe, might show evidence for antimatter. X-ray emission shows how much hot gas is involved in such a collision. If some of the gas from either cluster has particles of antimatter, then there will be annihilation and the X-rays will be accompanied by gamma rays. Steigman used data obtained by Chandra and Compton to study the so-called Bullet Cluster, where two large clusters of galaxies have crashed into one another at extremely high velocities. At a relatively close distance and with a favorable side-on orientation as viewed from Earth, the Bullet Cluster provides an excellent test site to search for the signal for antimatter. People Who Read This Also Read... Jet Power and Black Hole Assortment Revealed in New Chandra Image Chandra Data Reveal Rapidly Whirling Black Holes Black Holes Have Simple Feeding Habits Galaxies Coming of Age in Cosmic Blobs "This is the largest scale over which this test for antimatter has ever been done," said Steigman, whose paper was published in the Journal of Cosmology and Astroparticle Physics. "I'm looking to see if there could be any clusters of galaxies which are made of large amounts of antimatter." The observed amount of X-rays from Chandra and the non-detection of gamma rays from the Compton data show that the antimatter fraction in the Bullet Cluster is less than three parts per million. Moreover, simulations of the Bullet Cluster merger show that these results rule out any significant amounts of antimatter over scales of about 65 million light years, an estimate of the original separation of the two colliding clusters. "The collision of matter and antimatter is the most efficient process for generating energy in the Universe, but it just may not happen on very large scales," said Steigman. "But, I'm not giving up yet as I'm planning to look at other colliding galaxy clusters that have recently been discovered." Finding antimatter in the Universe might tell scientists about how long the period of inflation lasted. "Success in this experiment, although a long shot, would teach us a lot about the earliest stages of the Universe," said Steigman. Tighter constraints have been placed by Steigman on the presence of antimatter on smaller scales by looking at single galaxy clusters that do not involve such large, recent collisions. The Compton Gamma Ray Observatory was in orbit from 1991 until 2000 when it was safely de-orbited. The data used in this result came from Compton's Energetic Gamma Ray Telescope, or EGRET, instrument. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

A Multi-Discipline, Multi-Genre Digital Library for Research and Education

NASA Technical Reports Server (NTRS)

Nelson, Michael L.; Maly, Kurt; Shen, Stewart N. T.

2004-01-01

We describe NCSTRL+, a unified, canonical digital library for educational and scientific and technical information (STI). NCSTRL+ is based on the Networked Computer Science Technical Report Library (NCSTRL), a World Wide Web (WWW) accessible digital library (DL) that provides access to over 100 university departments and laboratories. NCSTRL+ implements two new technologies: cluster functionality and publishing "buckets". We have extended the Dienst protocol, the protocol underlying NCSTRL, to provide the ability to "cluster" independent collections into a logically centralized digital library based upon subject category classification, type of organization, and genres of material. The concept of "buckets" provides a mechanism for publishing and managing logically linked entities with multiple data formats. The NCSTRL+ prototype DL contains the holdings of NCSTRL and the NASA Technical Report Server (NTRS). The prototype demonstrates the feasibility of publishing into a multi-cluster DL, searching across clusters, and storing and presenting buckets of information.

On the Analysis of Case-Control Studies in Cluster-correlated Data Settings.

PubMed

Haneuse, Sebastien; Rivera-Rodriguez, Claudia

2018-01-01

In resource-limited settings, long-term evaluation of national antiretroviral treatment (ART) programs often relies on aggregated data, the analysis of which may be subject to ecological bias. As researchers and policy makers consider evaluating individual-level outcomes such as treatment adherence or mortality, the well-known case-control design is appealing in that it provides efficiency gains over random sampling. In the context that motivates this article, valid estimation and inference requires acknowledging any clustering, although, to our knowledge, no statistical methods have been published for the analysis of case-control data for which the underlying population exhibits clustering. Furthermore, in the specific context of an ongoing collaboration in Malawi, rather than performing case-control sampling across all clinics, case-control sampling within clinics has been suggested as a more practical strategy. To our knowledge, although similar outcome-dependent sampling schemes have been described in the literature, a case-control design specific to correlated data settings is new. In this article, we describe this design, discuss balanced versus unbalanced sampling techniques, and provide a general approach to analyzing case-control studies in cluster-correlated settings based on inverse probability-weighted generalized estimating equations. Inference is based on a robust sandwich estimator with correlation parameters estimated to ensure appropriate accounting of the outcome-dependent sampling scheme. We conduct comprehensive simulations, based in part on real data on a sample of N = 78,155 program registrants in Malawi between 2005 and 2007, to evaluate small-sample operating characteristics and potential trade-offs associated with standard case-control sampling or when case-control sampling is performed within clusters.

SACS: Spitzer Archival Cluster Survey

NASA Astrophysics Data System (ADS)

Stern, Daniel

Emerging from the cosmic web, galaxy clusters are the most massive gravitationally bound structures in the universe. Thought to have begun their assembly at z > 2, clusters provide insights into the growth of large-scale structure as well as the physics that drives galaxy evolution. Understanding how and when the most massive galaxies assemble their stellar mass, stop forming stars, and acquire their observed morphologies in these environments remain outstanding questions. The redshift range 1.3 < z < 2 is a key epoch in this respect: elliptical galaxies start to become the dominant population in cluster cores, and star formation in spiral galaxies is being quenched. Until recently, however, this redshift range was essentially unreachable with available instrumentation, with clusters at these redshifts exceedingly challenging to identify from either ground-based optical/nearinfrared imaging or from X-ray surveys. Mid-infrared (MIR) imaging with the IRAC camera on board of the Spitzer Space Telescope has changed the landscape. High-redshift clusters are easily identified in the MIR due to a combination of the unique colors of distant galaxies and a negative k-correction in the 3-5 μm range which makes such galaxies bright. Even 90-sec observations with Spitzer/IRAC, a depth which essentially all extragalactic observations in the archive achieve, is sufficient to robustly detect overdensities of L* galaxies out to z~2. Here we request funding to embark on a ambitious scientific program, the “SACS: Spitzer Archival Cluster Survey”, a comprehensive search for the most distant galaxy clusters in all Spitzer/IRAC extragalactic pointings available in the archive. With the SACS we aim to discover ~2000 of 1.3 < z < 2.5 clusters, thus provide the ultimate catalog for high-redshift MIR selected clusters: a lasting legacy for Spitzer. The study we propose will increase by more than a factor of 10 the number of high-redshift clusters discovered by all previous surveys combined, providing a high-purity, uniform sample. Matching the Spitzer/IRAC-selected clusters with data at similar and longer wavelengths available in the archive (WISE 3- 5μm, Spitzer/MIPS 24μm or Herschel/SPIRE 250μm data) we will be also able to study the dependence on the environment of star formation and AGN activity out to z~2, and to study the effect of star-forming galaxies and AGNs on cosmological results from ongoing Sunyaev-Zel'dovich (SZ) and X-ray cluster surveys. The identified clusters will be valuable for both astrophysics and cosmology. In terms of astrophysics, the redshift probed by the MIR color selection targets a key epoch in cluster development, when star formation is shutting down and the galaxies are becoming passive. Massive clusters also distort space-time around them, creating powerful gravitational telescopes that lens the distant universe. This both allows detailed studies of the lensed objects with otherwise unachievable sensitivity, as well as provides a unique probe of the mass distribution in the lensing cluster. In terms of cosmology, clusters are the most massive structures in the universe, and their space density is sensitive to basic cosmological parameters. Clusters identified by this program will become a lasting legacy of Spitzer, providing exciting targets for Chandra, Hubble, James Webb Space Telescope (JWST), Astro-H, Athena, as well as future 30-m class ground-based telescopes (e.g., GMT, ELT, TMT). The upcoming large-scale, space-based surveys of eROSITA, Euclid, and WFIRST all have distant cluster studies as key scientific goals. Our proposed survey will provide new high redshift targets for those satellites, enabling unique, exciting multi-wavelength studies of the Spitzer-selected sample, as well as a training set to identify additional high-redshift clusters outside of the Spitzer footprint.

Self-management education for rehabilitation inpatients suffering from inflammatory bowel disease: a cluster-randomized controlled trial.

PubMed

Reusch, A; Weiland, R; Gerlich, C; Dreger, K; Derra, C; Mainos, D; Tuschhoff, T; Berding, A; Witte, C; Kaltz, B; Faller, H

2016-12-01

Although inflammatory bowel disease (IBD) affects patients' psychological well-being, previous educational programs have failed to demonstrate effects on psychosocial outcomes and quality of life. Therefore, we developed a group-based psychoeducational program that combined provision of both medical information and psychological self-management skills, delivered in an interactive manner, and evaluated it in a large, cluster-randomized trial. We assigned 540 rehabilitation inpatients suffering from IBD (mean age 43 years, 66% female) to either the new intervention or a control group comprising the same overall intensity and the same medical information, but only general psychosocial information. The primary outcome was patient-reported IBD-related concerns. Secondary outcomes included disease knowledge, coping, self-management skills, fear of progression, anxiety, depression and quality of life. Assessments took place at baseline, end of rehabilitation and after 3 and 12 months.The psychoeducational self-management program did not prove superior to the control group regarding primary and secondary outcomes. However, positive changes over time occurred in both groups regarding most outcomes. The superior effectiveness of the newly developed psychoeducational program could not be demonstrated. Since the intervention and control groups may have been too similar, this trial may have been too conservative to produce between-group effects. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A first packet processing subdomain cluster model based on SDN

NASA Astrophysics Data System (ADS)

Chen, Mingyong; Wu, Weimin

2017-08-01

For the current controller cluster packet processing performance bottlenecks and controller downtime problems. An SDN controller is proposed to allocate the priority of each device in the SDN (Software Defined Network) network, and the domain contains several network devices and Controller, the controller is responsible for managing the network equipment within the domain, the switch performs data delivery based on the load of the controller, processing network equipment data. The experimental results show that the model can effectively solve the risk of single point failure of the controller, and can solve the performance bottleneck of the first packet processing.

A Proposal to Investigate Outstanding Problems in Astronomy

NASA Technical Reports Server (NTRS)

Ford, Holland

2004-01-01

Holland Ford and Garth Illingworth organized, managed, and coordinated a very successful year of work by the ACS science team. The team is working well together on analysis of ACS observations and supporting data from other satellites and from ground-based observations. Many important papers have been published or submitted, spanning science from observations of newly discovered debris disks around young stars, to the characterization of galaxy clusters at half the age of the Universe, to observations of proto-clusters with ages of approx. 2 billion years, to searches for galaxies forming within the first billion years after the birth of the universe. One important milestone during the year was the annual team meeting during September. The meeting, organized and led by Holland and Garth, produced a plan for analysis of ACS observations during the coming year, and a plan for obtaining supporting observations with large ground-based telescopes.

School intervention to improve mental health of students in Santiago, Chile: a randomized clinical trial.

PubMed

Araya, Ricardo; Fritsch, Rosemarie; Spears, Melissa; Rojas, Graciela; Martinez, Vania; Barroilhet, Sergio; Vöhringer, Paul; Gunnell, David; Stallard, Paul; Guajardo, Viviana; Gaete, Jorge; Noble, Sian; Montgomery, Alan A

2013-11-01

Depression can have devastating effects unless prevented or treated early and effectively. Schools offer an excellent opportunity to intervene with adolescents presenting emotional problems. There are very few universal school-based depression interventions conducted in low- and middle-income countries. To assess the effectiveness of a school-based, universal psychological intervention to reduce depressive symptoms among adolescents from low-income families. A 2-arm, parallel, cluster, randomized clinical trial was conducted in secondary schools in deprived socioeconomic areas of Santiago, Chile. Almost all students registered in the selected schools consented to take part in the study. A total of 2512 secondary school students from 22 schools and 66 classes participated. Students in the intervention arm attended 11 one-hour weekly and 2 booster classroom sessions of an intervention based on cognitive-behavioral models. The intervention was delivered by trained nonspecialists. Schools in the control arm received the standard school curriculum. Scores on the self-administered Beck Depression Inventory-II at 3 months (primary) and 12 months (secondary) after completing the intervention. There were 1291 participants in the control arm and 1221 in the intervention arm. Primary outcome data were available for 82.1% of the participants. There was no evidence of any clinically important difference in mean depression scores between the groups (adjusted difference in mean, -0.19; 95% CI, -1.22 to 0.84) or for any of the other outcomes 3 months after completion of the intervention. No significant differences were found in any of the outcomes at 12 months. A well-designed and implemented school-based intervention did not reduce depressive symptoms among socioeconomically deprived adolescents in Santiago, Chile. There is growing evidence that universal school interventions may not be sufficiently effective to reduce or prevent depressive symptoms. isrctn.org Identifier: ISRCTN19466209.

Opening Address

NASA Astrophysics Data System (ADS)

Yamada, T.

2014-12-01

Ladies and Gentlemen, it is my great honor and pleasure to present an opening address of the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3). On the behalf of the organizing committee, I certainly welcome all your visits to KGU Kannai Media Center belonging to Kanto Gakuin University, and stay in Yokohama. In particular, to whom come from abroad more than 17 countries, I would appreciate your participations after long long trips from your homeland to Yokohama. The first international workshop on "State of the Art in Nuclear Cluster Physics", called SOTANCP, was held in Strasbourg, France, in 2008, and the second one was held in Brussels, Belgium, in 2010. Then the third workshop is now held in Yokohama. In this period, we had the traditional 10th cluster conference in Debrecen, Hungary, in 2012. Thus we have the traditional cluster conference and SOTANCP, one after another, every two years. This obviously shows our field of nuclear cluster physics is very active and flourishing. It is for the first time in about 10 years to hold the international workshop on nuclear cluster physics in Japan, because the last cluster conference held in Japan was in Nara in 2003, about 10 years ago. The president in Nara conference was Prof. K. Ikeda, and the chairpersons were Prof. H. Horiuchi and Prof. I. Tanihata. I think, quite a lot of persons in this room had participated at the Nara conference. Since then, about ten years passed. So, this workshop has profound significance for our Japanese colleagues. The subjects of this workshop are to discuss "the state of the art in nuclear cluster physics" and also discuss the prospect of this field. In a couple of years, we saw significant progresses of this field both in theory and in experiment, which have brought better and new understandings on the clustering aspects in stable and unstable nuclei. I think, the concept of clustering has been more important than ever. This is true also in the related fields such as nuclear astrophysics, hypernuclear physics, hadron physics, and condensate matter physics so on. In fact, in this workshop, we also discuss the clustering aspects in the related fields. Thus, I expect in this workshop we can grasp the present status of the nuclear cluster physics and demonstrate its perspective in near future. This workshop is sponsored by several institutes and organizations. In particular, I would express our thanks for financial supports to Research Center for Nuclear Physics (RCNP), Osaka University, Center for Nuclear Study (CNS), University of Tokyo, Joint Institute for Computational Fundamental Science (JICFuS), and RIKEN Nishina Center for Accelerator- Based Science. They are cohosting this workshop. I would like also to appreciate my University, Kanto Gakuin University, who offers this nice place for one week and helps us to hold this workshop smoothly and conveniently. Today, the president of my University, Prof. Kuku, is here to present a welcome address. Thank you very much. Finally, with many of the participants leading this field both in theory and in experiment, we wish this workshop offers an opportunity to simulate communications not only during the workshop but also in the future. In addition, we hope you enjoy exploring city of Yokohama and the area around, as well as scientific discussions. Thank you very much for your attention.

Preventing substance misuse: study protocol for a randomised controlled trial of the Strengthening Families Programme 10–14 UK (SFP 10–14 UK)

PubMed Central

2014-01-01

Background Prevention of alcohol, drug and tobacco misuse by young people is a key public health priority. There is a need to develop the evidence base through rigorous evaluations of innovative approaches to substance misuse prevention. The Strengthening Families Programme 10–14 is a universal family-based alcohol, drugs and tobacco prevention programme, which has achieved promising results in US trials, and which now requires cross-cultural assessment. This paper therefore describes the protocol for a randomised controlled trial of the UK version of the Strengthening Families Programme 10–14 (SFP 10–14 UK). Methods/Design The trial comprises a pragmatic cluster randomised controlled effectiveness trial with families as the unit of randomisation, with embedded process and economic evaluations. Participating families will be randomised to one of two treatment groups - usual care with full access to existing services (control group), or usual care plus SFP 10–14 UK (intervention group). The trial has two primary outcomes - the number of occasions that young people report having drunk alcohol in the last 30 days, and drunkenness during the last 30 days, both dichotomised as ‘never’ and ‘1-2 times or more’. The main follow-up is at 2 years past baseline, and short-term and intermediate outcomes are also measured at 9 and 15 months. Discussion The results from this trial will provide evidence on the effectiveness and cost-effectiveness of an innovative universal family-based substance misuse prevention programme in a UK context. Trial registration Current Controlled Trials ISRCTN63550893. PMID:24438460

White Dwarf Stars

NASA Technical Reports Server (NTRS)

1999-01-01

Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope has uncovered the oldest burned-out stars in our Milky Way Galaxy, giving astronomers a fresh reading on the age of the universe.

Located in the globular cluster M4, these small, burned-out stars -- called white dwarfs -- are about 12 to 13 billion years old. By adding the one billion years it took the cluster to form after the Big Bang, astronomers found that the age of the white dwarfs agrees with previous estimates that the universe is 13 to 14 billion years old.

The images, including some taken by Hubble's Wide Field and Planetary Camera 2, are available online at

http://oposite.stsci.edu/pubinfo/pr/2002/10/ or

http://www.jpl.nasa.gov/images/wfpc .

The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif.

In the top panel, a ground-based observatory snapped a panoramic view of the entire cluster, which contains several hundred thousand stars within a volume of 10 to 30 light-years across. The Kitt Peak National Observatory's .9-meter telescope took this picture in March 1995. The box at left indicates the region observed by the Hubble telescope.

The Hubble telescope studied a small region of the cluster. A section of that region is seen in the picture at bottom left. A sampling of an even smaller region is shown at bottom right. This region is only about one light-year across. In this smaller region, Hubble pinpointed a number of faint white dwarfs. The blue circles indicate the dwarfs. It took nearly eight days of exposure time over a 67-day period to find these extremely faint stars.

Globular clusters are among the oldest clusters of stars in the universe. The faintest and coolest white dwarfs within globular clusters can yield a globular cluster's age. Earlier Hubble observations showed that the first stars formed less than 1 billion years after the universe's birth in the big bang. So, finding the oldest stars puts astronomers within arm's reach of the universe's age.

Hubble's Wide Field and Planetary Camera 2 made the observations from January through April 2001. These optical observations were combined to create the above images. Spectral data were also taken. M4 is 7,000 light-years away in the constellation Scorpius.

The full press release on the latest findings is online at

http://oposite.stsci.edu/pubinfo/pr/2002/10/pr.html .

The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between the European Space Agency and NASA. The California Institute of Technology in Pasadena manages JPL for NASA.

Novel approaches to pin cluster synchronization on complex dynamical networks in Lur'e forms

NASA Astrophysics Data System (ADS)

Tang, Ze; Park, Ju H.; Feng, Jianwen

2018-04-01

This paper investigates the cluster synchronization of complex dynamical networks consisted of identical or nonidentical Lur'e systems. Due to the special topology structure of the complex networks and the existence of stochastic perturbations, a kind of randomly occurring pinning controller is designed which not only synchronizes all Lur'e systems in the same cluster but also decreases the negative influence among different clusters. Firstly, based on an extended integral inequality, the convex combination theorem and S-procedure, the conditions for cluster synchronization of identical Lur'e networks are derived in a convex domain. Secondly, randomly occurring adaptive pinning controllers with two independent Bernoulli stochastic variables are designed and then sufficient conditions are obtained for the cluster synchronization on complex networks consisted of nonidentical Lur'e systems. In addition, suitable control gains for successful cluster synchronization of nonidentical Lur'e networks are acquired by designing some adaptive updating laws. Finally, we present two numerical examples to demonstrate the validity of the control scheme and the theoretical analysis.

Galaxy Clusters, Near and Far, Have a Lot in Common

NASA Astrophysics Data System (ADS)

2005-04-01

Using two orbiting X-ray telescopes, a team of international astronomers has examined distant galaxy clusters in order to compare them with their counterparts that are relatively close by. Speaking today at the RAS National Astronomy Meeting in Birmingham, Dr. Ben Maughan (Harvard-Smithsonian Center for Astrophysics), presented the results of this new analysis. The observations indicate that, despite the great expansion that the Universe has undergone since the Big Bang, galaxy clusters both local and distant have a great deal in common. This discovery could eventually lead to a better understanding of how to "weigh" these enormous structures, and, in so doing, answer important questions about the nature and structure of the Universe. Clusters of galaxies, the largest known gravitationally-bound objects, are the knots in the cosmic web of structure that permeates the Universe. Theoretical models make predictions about the number, distribution and properties of these clusters. Scientists can test and improve models of the Universe by comparing these predictions with observations. The most powerful way of doing this is to measure the masses of galaxy clusters, particularly those in the distant Universe. However, weighing galaxy clusters is extremely difficult. One relatively easy way to weigh a galaxy cluster is to use simple laws ("scaling relations") to estimate its weight from properties that are easy to observe, like its luminosity (brightness) or temperature. This is like estimating someone's weight from their height if you didn't have any scales. Over the last 3 years, a team of researchers, led by Ben Maughan, has observed 11 distant galaxy clusters with ESA's XMM-Newton and NASA's Chandra X-ray Observatory. The clusters have redshifts of z = 0.6-1.0, which corresponds to distances of 6 to 8 billion light years. This means that we see them as they were when the Universe was half its present age. The survey included two unusual systems, one in which two massive clusters are merging and another extremely massive cluster which appears very "relaxed" and undisturbed. The X-ray data allowed the scientists to measure the temperatures and luminosities of the gas in the clusters. They were then able to infer their total masses, which varied between 200 and 1,100 times the mass of our Milky Way galaxy. These measurements were then used to test whether galaxy clusters of different sizes and located at different distances from us are simply scaled versions of each other -- a condition known as being "self-similar." This is an important characteristic for astronomers to identify if they hope to get the true weights of galaxy clusters. "For example, chocolate bars are strongly self-similar," said Maughan. "If you shrank a king-size bar to a fun-size bar, they would be identical versions of each other but just different sizes." "However, if you shrank a castle to the size of a bungalow, they would be very different structures, despite being the same size. This means that they are not strongly self-similar objects." Another possible type of relationship between clusters is what scientists call "weakly self-similar." In this case, galaxy clusters in the distant universe and those nearby are almost identical to each other, but not exactly the same. (The only differences between them can be accounted for by the expansion of the Universe since the Big Bang.) Although astronomers have known for some time that galaxy clusters are not strongly self-similar, the question of whether or not they are weakly self-similar has remained open. The new results show that as long as astronomers take into account the continuous expansion of the Universe, then galaxy clusters are, in fact, weakly self-similar. This means that the same scaling relations used to weigh nearby galaxy clusters hold true for these very distant clusters. "Our results mean that weighing distant galaxy clusters could become as easy as converting from Fahrenheit to Celsius," said Maughan. "This will help to answer important questions about the nature and structure of the Universe." The other members of the team were: Laurence Jones (University of Birmingham, UK) Harald Ebeling (Institute for Astronomy, HI, USA), and Caleb Scharf (Columbia Astrophysics Laboratory, NY, USA). The observations were made with the European Photon Imaging Camera (EPIC) on XMM and the Advanced Camera for Imaging and Spectroscopy (ACIS) on Chandra. They were part of the WARPS survey of distant galaxy clusters detected by chance in observations made with the UK-US-Dutch ROSAT X-ray satellite. Additional information and images are available at: http://www.sr.bham.ac.uk/~habib/nampr/

Cosmic Pressure Fronts Mapped by Chandra

NASA Astrophysics Data System (ADS)

2000-03-01

A colossal cosmic "weather system" produced by the collision of two giant clusters of galaxies has been imaged by NASA's Chandra X-ray Observatory. For the first time, the pressure fronts in the system can be traced in detail, and they show a bright, but relatively cool 50 million degree Celsius central region embedded in large elongated cloud of 70 million degree Celsius gas, all of which is roiling in a faint "atmosphere"of 100 million degree Celsius gas. "We can compare this to an intergalactic cold front," said Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. and leader of the international team involved in the analysis of the observations. "A major difference is that in this case, cold means 70 million degree Celsius." The gas clouds are in the core of a galaxy cluster known as Abell 2142. The cluster is six million light years across and contains hundreds of galaxies and enough gas to make a thousand more. It is one of the most massive objects in the universe. Galaxy clusters grow to vast sizes as smaller clusters are pulled inward under the influence of gravity. They collide and merge over the course of billions of years, releasing tremendous amounts of energy that heats the cluster gas to 100 million degrees Celsius. The Chandra data provides the first detailed look at the late stages of this merger process. Previously, scientists had used the German-US Roentgensatellite to produce a broad brush picture of the cluster. The elongated shape of the bright cloud suggested that two clouds were in the process of coalescing into one, but the details remained unclear. Chandra is able to measure variations of temperature, density, and pressure with unprecedented resolution. "Now we can begin to understand the physics of these mergers, which are among the most energetic events in the universe," said Markevitch. "The pressure and density maps of the cluster show a sharp boundary that can only exist in the moving environment of a merger." With this information scientists can make a comparison with computer simulations of cosmic mergers. This comparison, which is in the early stages, shows that this merger has progressed to an advanced stage. Strong shock waves predicted by the theory for the initial collision of clusters are not observed. It appears likely that these sub-clusters have collided two or three times in a billion years or more, and have nearly completed their merger. The observations were made on August 20, 1999 using the Advanced CCD Imaging Spectrometer (ACIS). The team involved scientists from Harvard-Smithsonian; the Massachusetts Institute of Technology, Cambridge; NASA's Marshall Space Flight Center, Huntsville, Ala.; the University of Hawaii, Honolulu; the University of Birmingham, U.K.; the University of Wollongong, Australia; the Space Research Organization Netherlands; the University of Rome, Italy; and the Russian Academy of Sciences. The results will be published in an upcoming issue of the Astrophysical Journal. The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University, University Park. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass. For images connected to this release, and to follow Chandra's progress, visit the Chandra site at: http://chandra.harvard.edu/photo/2000/a2142/index.html AND http://chandra.nasa.gov High resolution digital versions of the X-ray image (JPG, 300 dpi TIFF) are available at the Internet sites listed above. This image will be available on NASA Video File which airs at noon, 3:00 p.m., 6:00 p.m., 9:00 p.m. and midnight Eastern Time. NASA Television is available on GE-2, transponder 9C at 85 degrees West longitude, with vertical polarization. Frequency is on 3880.0 megahertz, with audio on 6.8 megahertz.

Irie Classroom Toolbox: a study protocol for a cluster-randomised trial of a universal violence prevention programme in Jamaican preschools

PubMed Central

Baker-Henningham, Helen; Vera-Hernández, Marcos; Alderman, Harold; Walker, Susan

2016-01-01

Introduction We aim to determine the effectiveness of a school-based violence prevention programme implemented in Jamaican preschools, on reducing the levels of aggression among children at school, and violence against children by teachers. Methods and analysis This is a 2-arm, single-blind, cluster-randomised controlled trial with parallel assignment. Clusters are 76 preschools in Kingston, and all teachers and classrooms in the selected schools are included in the study. In addition, a random sample of up to 12 children in the 4-year-old classes have been selected for evaluation of child-level outcomes. The intervention involves training teachers in classroom behaviour management and in strategies to promote children's social-emotional competence. Training is delivered through five full-day workshops, monthly in-class coaching over 2 school terms, and weekly text messages. The primary outcome measures are: (1) observed levels of child aggression and (2) observed violence against children by teachers. Secondary outcomes include observations of the levels of children's prosocial behaviour and the quality of the classroom environment, teachers’ reports of their mental health, teacher-reported child mental health, direct tests of children's self-regulation and child attendance. Ethics and dissemination If this intervention were effective at improving the caregiving environment of young children in school, this would have significant implications for the prevention of child mental health problems, and prevention of violence against children in low and middle-income countries where services are often limited. The intervention is integrated into the school system and involves training existing staff, and thus, represents an appropriate strategy for large-scale implementation and benefits at the population level. Ethical consent for the study was given by the School of Psychology Ethics and Research Committee, Bangor University (ref: 2014-14167), and by the University of the West Indies Ethics Committee (ref: ECP 50,14/15). Trial registration number ISRCTN11968472; Pre-results. PMID:27165651

Maternal and Child Health Handbook use for maternal and child care: a cluster randomized controlled study in rural Java, Indonesia.

PubMed

Osaki, Keiko; Hattori, Tomoko; Toda, Akemi; Mulati, Erna; Hermawan, Lukas; Pritasari, Kirana; Bardosono, Saptawati; Kosen, Soewarta

2018-01-09

Effectiveness of the Maternal and Child Health Handbook (MCHHB), a home-based booklet for pregnancy, delivery and postnatal/child health, was evaluated on care acquisition and home care in rural Java, a low service-coverage area. We conducted a health centre-based randomized trial, with a 2-year follow-up. Intervention included (i) MCHHB provision at antenatal care visits; (ii) records and guides by health personnel on and with the MCHHB; and (iii) sensitization of care by volunteers using the MCHHB. The follow-up rate was 70.2% (183, intervention area; 271, control area). Respondents in the intervention area received consecutive MCH services including two doses of tetanus toxoid injections and antenatal care four times or more during pregnancy, professional assistance during child delivery and vitamin A supplements administration to their children, after adjustment for confounding variables and cluster effects (OR = 2.03, 95% CI: 1.19-3.47). In the intervention area, home care (continued breastfeeding; introducing complementary feeding; proper feeding order; varied foods feeding; self-feeding training; and care for cough), perceived support by husbands, and lower underweight rates and stunting rates among children were observed. MCHHB use promoted continuous care acquisition and care at home from pregnancy to early child-rearing stages in rural Java. © The Author(s) 2018. Published by Oxford University Press on behalf of Faculty of Public Health.

Reducing child conduct problems and promoting social skills in a middle-income country: cluster randomised controlled trial.

PubMed

Baker-Henningham, Helen; Scott, Stephen; Jones, Kelvyn; Walker, Susan

2012-08-01

There is an urgent need for effective, affordable interventions to prevent child mental health problems in low- and middle-income countries. To determine the effects of a universal pre-school-based intervention on child conduct problems and social skills at school and at home. In a cluster randomised design, 24 community pre-schools in inner-city areas of Kingston, Jamaica, were randomly assigned to receive the Incredible Years Teacher Training intervention (n = 12) or to a control group (n = 12). Three children from each class with the highest levels of teacher-reported conduct problems were selected for evaluation, giving 225 children aged 3-6 years. The primary outcome was observed child behaviour at school. Secondary outcomes were child behaviour by parent and teacher report, child attendance and parents' attitude to school. The study is registered as ISRCTN35476268. Children in intervention schools showed significantly reduced conduct problems (effect size (ES) = 0.42) and increased friendship skills (ES = 0.74) through observation, significant reductions to teacher-reported (ES = 0.47) and parent-reported (ES = 0.22) behaviour difficulties and increases in teacher-reported social skills (ES = 0.59) and child attendance (ES = 0.30). Benefits to parents' attitude to school were not significant. A low-cost, school-based intervention in a middle-income country substantially reduces child conduct problems and increases child social skills at home and at school.

Partially supervised speaker clustering.

PubMed

Tang, Hao; Chu, Stephen Mingyu; Hasegawa-Johnson, Mark; Huang, Thomas S

2012-05-01

Content-based multimedia indexing, retrieval, and processing as well as multimedia databases demand the structuring of the media content (image, audio, video, text, etc.), one significant goal being to associate the identity of the content to the individual segments of the signals. In this paper, we specifically address the problem of speaker clustering, the task of assigning every speech utterance in an audio stream to its speaker. We offer a complete treatment to the idea of partially supervised speaker clustering, which refers to the use of our prior knowledge of speakers in general to assist the unsupervised speaker clustering process. By means of an independent training data set, we encode the prior knowledge at the various stages of the speaker clustering pipeline via 1) learning a speaker-discriminative acoustic feature transformation, 2) learning a universal speaker prior model, and 3) learning a discriminative speaker subspace, or equivalently, a speaker-discriminative distance metric. We study the directional scattering property of the Gaussian mixture model (GMM) mean supervector representation of utterances in the high-dimensional space, and advocate exploiting this property by using the cosine distance metric instead of the euclidean distance metric for speaker clustering in the GMM mean supervector space. We propose to perform discriminant analysis based on the cosine distance metric, which leads to a novel distance metric learning algorithm—linear spherical discriminant analysis (LSDA). We show that the proposed LSDA formulation can be systematically solved within the elegant graph embedding general dimensionality reduction framework. Our speaker clustering experiments on the GALE database clearly indicate that 1) our speaker clustering methods based on the GMM mean supervector representation and vector-based distance metrics outperform traditional speaker clustering methods based on the “bag of acoustic features” representation and statistical model-based distance metrics, 2) our advocated use of the cosine distance metric yields consistent increases in the speaker clustering performance as compared to the commonly used euclidean distance metric, 3) our partially supervised speaker clustering concept and strategies significantly improve the speaker clustering performance over the baselines, and 4) our proposed LSDA algorithm further leads to state-of-the-art speaker clustering performance.

The Cluster Concept Program Developed by the University of Maryland, Industrial Education Department.

ERIC Educational Resources Information Center

Kratochvil, Daniel W.; Thompson, Lorna J.

This report, one of 21 case studies, describes the history of a recent educational product. The Cluster Concept Program, developed at the University of Maryland, is directed toward the preparation of individuals for entrance into a spectrum of occupations. Three clusters of occupations are included: (1) Construction, (2) Electro-Mechanical…

Coordinate based random effect size meta-analysis of neuroimaging studies.

PubMed

Tench, C R; Tanasescu, Radu; Constantinescu, C S; Auer, D P; Cottam, W J

2017-06-01

Low power in neuroimaging studies can make them difficult to interpret, and Coordinate based meta-analysis (CBMA) may go some way to mitigating this issue. CBMA has been used in many analyses to detect where published functional MRI or voxel-based morphometry studies testing similar hypotheses report significant summary results (coordinates) consistently. Only the reported coordinates and possibly t statistics are analysed, and statistical significance of clusters is determined by coordinate density. Here a method of performing coordinate based random effect size meta-analysis and meta-regression is introduced. The algorithm (ClusterZ) analyses both coordinates and reported t statistic or Z score, standardised by the number of subjects. Statistical significance is determined not by coordinate density, but by a random effects meta-analyses of reported effects performed cluster-wise using standard statistical methods and taking account of censoring inherent in the published summary results. Type 1 error control is achieved using the false cluster discovery rate (FCDR), which is based on the false discovery rate. This controls both the family wise error rate under the null hypothesis that coordinates are randomly drawn from a standard stereotaxic space, and the proportion of significant clusters that are expected under the null. Such control is necessary to avoid propagating and even amplifying the very issues motivating the meta-analysis in the first place. ClusterZ is demonstrated on both numerically simulated data and on real data from reports of grey matter loss in multiple sclerosis (MS) and syndromes suggestive of MS, and of painful stimulus in healthy controls. The software implementation is available to download and use freely. Copyright © 2017 Elsevier Inc. All rights reserved.

Chandra Independently Determines Hubble Constant

NASA Astrophysics Data System (ADS)

2006-08-01

A critically important number that specifies the expansion rate of the Universe, the so-called Hubble constant, has been independently determined using NASA's Chandra X-ray Observatory. This new value matches recent measurements using other methods and extends their validity to greater distances, thus allowing astronomers to probe earlier epochs in the evolution of the Universe. "The reason this result is so significant is that we need the Hubble constant to tell us the size of the Universe, its age, and how much matter it contains," said Max Bonamente from the University of Alabama in Huntsville and NASA's Marshall Space Flight Center (MSFC) in Huntsville, Ala., lead author on the paper describing the results. "Astronomers absolutely need to trust this number because we use it for countless calculations." Illustration of Sunyaev-Zeldovich Effect Illustration of Sunyaev-Zeldovich Effect The Hubble constant is calculated by measuring the speed at which objects are moving away from us and dividing by their distance. Most of the previous attempts to determine the Hubble constant have involved using a multi-step, or distance ladder, approach in which the distance to nearby galaxies is used as the basis for determining greater distances. The most common approach has been to use a well-studied type of pulsating star known as a Cepheid variable, in conjunction with more distant supernovae to trace distances across the Universe. Scientists using this method and observations from the Hubble Space Telescope were able to measure the Hubble constant to within 10%. However, only independent checks would give them the confidence they desired, considering that much of our understanding of the Universe hangs in the balance. Chandra X-ray Image of MACS J1149.5+223 Chandra X-ray Image of MACS J1149.5+223 By combining X-ray data from Chandra with radio observations of galaxy clusters, the team determined the distances to 38 galaxy clusters ranging from 1.4 billion to 9.3 billion light years from Earth. These results do not rely on the traditional distance ladder. Bonamente and his colleagues find the Hubble constant to be 77 kilometers per second per megaparsec (a megaparsec is equal to 3.26 million light years), with an uncertainty of about 15%. This result agrees with the values determined using other techniques. The Hubble constant had previously been found to be 72, give or take 8, kilometers per second per megaparsec based on Hubble Space Telescope observations. The new Chandra result is important because it offers the independent confirmation that scientists have been seeking and fixes the age of the Universe between 12 and 14 billion years. Chandra X-ray Image of CL J1226.9+3332 Chandra X-ray Image of CL J1226.9+3332 "These new results are entirely independent of all previous methods of measuring the Hubble constant," said team member Marshall Joy also of MSFC. The astronomers used a phenomenon known as the Sunyaev-Zeldovich effect, where photons in the cosmic microwave background (CMB) interact with electrons in the hot gas that pervades the enormous galaxy clusters. The photons acquire energy from this interaction, which distorts the signal from the microwave background in the direction of the clusters. The magnitude of this distortion depends on the density and temperature of the hot electrons and the physical size of the cluster. Using radio telescopes to measure the distortion of the microwave background and Chandra to measure the properties of the hot gas, the physical size of the cluster can be determined. From this physical size and a simple measurement of the angle subtended by the cluster, the rules of geometry can be used to derive its distance. The Hubble constant is determined by dividing previously measured cluster speeds by these newly derived distances. Chandra X-ray Image of Abell 1689 Chandra X-ray Image of Abell 1689 This project was championed by Chandra's telescope mirror designer, Leon Van Speybroeck, who passed away in 2002. The foundation was laid when team members John Carlstrom (University of Chicago) and Marshall Joy obtained careful radio measurements of the distortions in the CMB radiation using radio telescopes at the Berkeley-Illinois-Maryland Array and the Caltech Owens Valley Radio Observatory. In order to measure the precise X-ray properties of the gas in these distant clusters, a space-based X-ray telescope with the resolution and sensitivity of Chandra was required. "It was one of Leon's goals to see this project happen, and it makes me very proud to see this come to fruition," said Chandra Project Scientist Martin Weisskopf of MSFC. The results are described in a paper appearing in the August 10th issue of The Astrophysical Journal. MSFC manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. Additional information and images can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

An AO-assisted Variability Study of Four Globular Clusters

NASA Astrophysics Data System (ADS)

Salinas, R.; Contreras Ramos, R.; Strader, J.; Hakala, P.; Catelan, M.; Peacock, M. B.; Simunovic, M.

2016-09-01

The image-subtraction technique applied to study variable stars in globular clusters represented a leap in the number of new detections, with the drawback that many of these new light curves could not be transformed to magnitudes due to severe crowding. In this paper, we present observations of four Galactic globular clusters, M 2 (NGC 7089), M 10 (NGC 6254), M 80 (NGC 6093), and NGC 1261, taken with the ground-layer adaptive optics module at the SOAR Telescope, SAM. We show that the higher image quality provided by SAM allows for the calibration of the light curves of the great majority of the variables near the cores of these clusters as well as the detection of new variables, even in clusters where image-subtraction searches were already conducted. We report the discovery of 15 new variables in M 2 (12 RR Lyrae stars and 3 SX Phe stars), 12 new variables in M 10 (11 SX Phe and 1 long-period variable), and 1 new W UMa-type variable in NGC 1261. No new detections are found in M 80, but previous uncertain detections are confirmed and the corresponding light curves are calibrated into magnitudes. Additionally, based on the number of detected variables and new Hubble Space Telescope/UVIS photometry, we revisit a previous suggestion that M 80 may be the globular cluster with the richest population of blue stragglers in our Galaxy. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Cluster Physics with Merging Galaxy Clusters

NASA Astrophysics Data System (ADS)

Molnar, Sandor

Collisions between galaxy clusters provide a unique opportunity to study matter in a parameter space which cannot be explored in our laboratories on Earth. In the standard ΛCDM model, where the total density is dominated by the cosmological constant (Λ) and the matter density by cold dark matter (CDM), structure formation is hierarchical, and clusters grow mostly by merging. Mergers of two massive clusters are the most energetic events in the universe after the Big Bang, hence they provide a unique laboratory to study cluster physics. The two main mass components in clusters behave differently during collisions: the dark matter is nearly collisionless, responding only to gravity, while the gas is subject to pressure forces and dissipation, and shocks and turbulence are developed during collisions. In the present contribution we review the different methods used to derive the physical properties of merging clusters. Different physical processes leave their signatures on different wavelengths, thus our review is based on a multifrequency analysis. In principle, the best way to analyze multifrequency observations of merging clusters is to model them using N-body/HYDRO numerical simulations. We discuss the results of such detailed analyses. New high spatial and spectral resolution ground and space based telescopes will come online in the near future. Motivated by these new opportunities, we briefly discuss methods which will be feasible in the near future in studying merging clusters.

Comparison and Evaluation of Clustering Algorithms for Tandem Mass Spectra.

PubMed

Rieder, Vera; Schork, Karin U; Kerschke, Laura; Blank-Landeshammer, Bernhard; Sickmann, Albert; Rahnenführer, Jörg

2017-11-03

In proteomics, liquid chromatography-tandem mass spectrometry (LC-MS/MS) is established for identifying peptides and proteins. Duplicated spectra, that is, multiple spectra of the same peptide, occur both in single MS/MS runs and in large spectral libraries. Clustering tandem mass spectra is used to find consensus spectra, with manifold applications. First, it speeds up database searches, as performed for instance by Mascot. Second, it helps to identify novel peptides across species. Third, it is used for quality control to detect wrongly annotated spectra. We compare different clustering algorithms based on the cosine distance between spectra. CAST, MS-Cluster, and PRIDE Cluster are popular algorithms to cluster tandem mass spectra. We add well-known algorithms for large data sets, hierarchical clustering, DBSCAN, and connected components of a graph, as well as the new method N-Cluster. All algorithms are evaluated on real data with varied parameter settings. Cluster results are compared with each other and with peptide annotations based on validation measures such as purity. Quality control, regarding the detection of wrongly (un)annotated spectra, is discussed for exemplary resulting clusters. N-Cluster proves to be highly competitive. All clustering results benefit from the so-called DISMS2 filter that integrates additional information, for example, on precursor mass.

The performance implications of pharmacy information system at the university teaching hospitals of Shiraz, Iran: Cluster approach

PubMed Central

Bayati, Saeede; Bastani, Peivand; Sagheb, Zahra Mahmoodzade; Jamalabadi, Sara; Samadbeik, Mahnaz

2017-01-01

Pharmacy information system (PIS) is becoming vital in assisting pharmacists to do their responsibilities. The aim of this study was to identify the current PIS implications in teaching hospitals affiliated with Shiraz University of Medical Science. This cross-sectional study was conducted in teaching hospitals affiliated with Shiraz University of Medical Science over the year 2016. Data were collected by observing the PIS as well as interviewing its users based on the researcher-made checklist. The checklist was prepared based on reviewing the Persian and English literature and its content validity was approved by the experts. To determine the reliability of the checklist, inter-rater reliability was used. Data were analyzed using SPSS16, and hospitals were clustered using SK-means method. In this study, the least conformity to the standards was shown in smart clinical features (4.54%), pharmaceutical companies' relationship (32.6%), and optimization of drug therapy (34.6%). In contrast, the highest conformity to the standards was shown in reporting capabilities (77.3%) and entry information and input (70.4%). Medication stock checking and optimization of drug therapy were effective features that have made a distinction between hospitals and lead to 95% variance between clusters. Based on the results, the current PIS design pays less attention to clinical features. Besides, clinical information for pharmacists and outside organization relationship were not provided by the current system. Thus, emphasis should be placed on the implementation of corrective actions to eliminate the current system's deficiencies. PMID:29184843

Qudit quantum computation on matrix product states with global symmetry

NASA Astrophysics Data System (ADS)

Wang, Dongsheng; Stephen, David; Raussendorf, Robert

Resource states that contain nontrivial symmetry-protected topological order are identified for universal measurement-based quantum computation. Our resource states fall into two classes: one as the qudit generalizations of the qubit cluster state, and the other as the higher-symmetry generalizations of the spin-1 Affleck-Kennedy-Lieb-Tasaki (AKLT) state, namely, with unitary, orthogonal, or symplectic symmetry. The symmetry in cluster states protects information propagation (identity gate), while the higher symmetry in AKLT-type states enables nontrivial gate computation. This work demonstrates a close connection between measurement-based quantum computation and symmetry-protected topological order.

Qudit quantum computation on matrix product states with global symmetry

NASA Astrophysics Data System (ADS)

Wang, Dong-Sheng; Stephen, David T.; Raussendorf, Robert

2017-03-01

Resource states that contain nontrivial symmetry-protected topological order are identified for universal single-qudit measurement-based quantum computation. Our resource states fall into two classes: one as the qudit generalizations of the one-dimensional qubit cluster state, and the other as the higher-symmetry generalizations of the spin-1 Affleck-Kennedy-Lieb-Tasaki (AKLT) state, namely, with unitary, orthogonal, or symplectic symmetry. The symmetry in cluster states protects information propagation (identity gate), while the higher symmetry in AKLT-type states enables nontrivial gate computation. This work demonstrates a close connection between measurement-based quantum computation and symmetry-protected topological order.

Network-based spatial clustering technique for exploring features in regional industry

NASA Astrophysics Data System (ADS)

Chou, Tien-Yin; Huang, Pi-Hui; Yang, Lung-Shih; Lin, Wen-Tzu

2008-10-01

In the past researches, industrial cluster mainly focused on single or particular industry and less on spatial industrial structure and mutual relations. Industrial cluster could generate three kinds of spillover effects, including knowledge, labor market pooling, and input sharing. In addition, industrial cluster indeed benefits industry development. To fully control the status and characteristics of district industrial cluster can facilitate to improve the competitive ascendancy of district industry. The related researches on industrial spatial cluster were of great significance for setting up industrial policies and promoting district economic development. In this study, an improved model, GeoSOM, that combines DBSCAN (Density-Based Spatial Clustering of Applications with Noise) and SOM (Self-Organizing Map) was developed for analyzing industrial cluster. Different from former distance-based algorithm for industrial cluster, the proposed GeoSOM model can calculate spatial characteristics between firms based on DBSCAN algorithm and evaluate the similarity between firms based on SOM clustering analysis. The demonstrative data sets, the manufacturers around Taichung County in Taiwan, were analyzed for verifying the practicability of the proposed model. The analyzed results indicate that GeoSOM is suitable for evaluating spatial industrial cluster.

Ionized cluster beam deposition

NASA Technical Reports Server (NTRS)

Kirkpatrick, A. R.

1983-01-01

Ionized Cluster Beam (ICB) deposition, a new technique originated by Takagi of Kyoto University in Japan, offers a number of unique capabilities for thin film metallization as well as for deposition of active semiconductor materials. ICB allows average energy per deposited atom to be controlled and involves impact kinetics which result in high diffusion energies of atoms on the growth surface. To a greater degree than in other techniques, ICB involves quantitative process parameters which can be utilized to strongly control the characteristics of films being deposited. In the ICB deposition process, material to be deposited is vaporized into a vacuum chamber from a confinement crucible at high temperature. Crucible nozzle configuration and operating temperature are such that emerging vapor undergoes supercondensation following adiabatic expansion through the nozzle.

Cluster analysis of dynamic contrast enhanced MRI reveals tumor subregions related to locoregional relapse for cervical cancer patients.

PubMed

Torheim, Turid; Groendahl, Aurora R; Andersen, Erlend K F; Lyng, Heidi; Malinen, Eirik; Kvaal, Knut; Futsaether, Cecilia M

2016-11-01

Solid tumors are known to be spatially heterogeneous. Detection of treatment-resistant tumor regions can improve clinical outcome, by enabling implementation of strategies targeting such regions. In this study, K-means clustering was used to group voxels in dynamic contrast enhanced magnetic resonance images (DCE-MRI) of cervical cancers. The aim was to identify clusters reflecting treatment resistance that could be used for targeted radiotherapy with a dose-painting approach. Eighty-one patients with locally advanced cervical cancer underwent DCE-MRI prior to chemoradiotherapy. The resulting image time series were fitted to two pharmacokinetic models, the Tofts model (yielding parameters K trans and ν e ) and the Brix model (A Brix , k ep and k el ). K-means clustering was used to group similar voxels based on either the pharmacokinetic parameter maps or the relative signal increase (RSI) time series. The associations between voxel clusters and treatment outcome (measured as locoregional control) were evaluated using the volume fraction or the spatial distribution of each cluster. One voxel cluster based on the RSI time series was significantly related to locoregional control (adjusted p-value 0.048). This cluster consisted of low-enhancing voxels. We found that tumors with poor prognosis had this RSI-based cluster gathered into few patches, making this cluster a potential candidate for targeted radiotherapy. None of the voxels clusters based on Tofts or Brix parameter maps were significantly related to treatment outcome. We identified one group of tumor voxels significantly associated with locoregional relapse that could potentially be used for dose painting. This tumor voxel cluster was identified using the raw MRI time series rather than the pharmacokinetic maps.

Regional Gray Matter Volumes Are Related to Concern About Falling in Older People: A Voxel-Based Morphometric Study.

PubMed

Tuerk, Carola; Zhang, Haobo; Sachdev, Perminder; Lord, Stephen R; Brodaty, Henry; Wen, Wei; Delbaere, Kim

2016-01-01

Concern about falling is common in older people. Various related psychological constructs as well as poor balance and slow gait have been associated with decreased gray matter (GM) volume in old age. The current study investigates the association between concern about falling and voxel-wise GM volumes. A total of 281 community-dwelling older people aged 70-90 years underwent structural magnetic resonance imaging. Concern about falling was assessed using Falls Efficacy Scale-International (FES-I). For each participant, voxel-wise GM volumes were generated with voxel-based morphometry and regressed on raw FES-I scores (p < .05 family-wise error corrected on cluster level). FES-I scores were negatively correlated with total brain volume (r = -.212; p ≤ .001), GM volume (r = -.210; p ≤ .001), and white matter volume (r = -.155; p ≤ .001). Voxel-based morphometry analysis revealed significant negative associations between FES-I and GM volumes of (i) left cerebellum and bilateral inferior occipital gyrus (voxels-in-cluster = 2,981; p < .001) and (ii) bilateral superior frontal gyrus and left supplementary motor area (voxels-in-cluster = 1,900; p = .004). Additional adjustment for vision and physical fall risk did not alter these associations. After adjustment for anxiety, only left cerebellum and bilateral inferior occipital gyrus remained negatively associated with FES-I scores (voxels-in-cluster = 2,426; p < .001). Adjustment for neuroticism removed all associations between FES-I and GM volumes. Our study findings show that concern about falling is negatively associated with brain volumes in areas important for emotional control and for motor control, executive functions and visual processing in a large sample of older men and women. Regression analyses suggest that these relationships were primarily accounted for by psychological factors (generalized anxiety and neuroticism) and not by physical fall risk or vision. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

New Fast Lane towards Discoveries of Clusters of Galaxies Inaugurated

NASA Astrophysics Data System (ADS)

2003-07-01

Space and Ground-Based Telescopes Cooperate to Gain Deep Cosmological Insights Summary Using the ESA XMM-Newton satellite, a team of European and Chilean astronomers [2] has obtained the world's deepest "wide-field" X-ray image of the cosmos to date. This penetrating view, when complemented with observations by some of the largest and most efficient ground-based optical telescopes, including the ESO Very Large Telescope (VLT), has resulted in the discovery of several large clusters of galaxies. These early results from an ambitious research programme are extremely promising and pave the way for a very comprehensive and thorough census of clusters of galaxies at various epochs. Relying on the foremost astronomical technology and with an unequalled observational efficiency, this project is set to provide new insights into the structure and evolution of the distant Universe. PR Photo 19a/03: First image from the XMM-LSS survey. PR Photo 19b/03: Zoom-in on PR Photo 19b/03. PR Photo 19c/03: XMM-Newton contour map of the probable extent of a cluster of galaxies, superimposed upon a CHFT I-band image. PR Photo 19d/03: Velocity distribution in the cluster field shown in PR Photo 19c/03. The universal web Unlike grains of sand on a beach, matter is not uniformly spread throughout the Universe. Instead, it is concentrated into galaxies which themselves congregate into clusters (and even clusters of clusters). These clusters are "strung" throughout the Universe in a web-like structure, cf. ESO PR 11/01. Our Galaxy, the Milky Way, for example, belongs to the so-called Local Group which also comprises "Messier 31", the Andromeda Galaxy. The Local Group contains about 30 galaxies and measures a few million light-years across. Other clusters are much larger. The Coma cluster contains thousands of galaxies and measures more than 20 million light-years. Another well known example is the Virgo cluster, covering no less than 10 degrees on the sky ! Clusters of galaxies are the most massive bound structures in the Universe. They have masses of the order of one thousand million million times the mass of our Sun. Their three-dimensional space distribution and number density change with cosmic time and provide information about the main cosmological parameters in a unique way. About one fifth of the optically invisible mass of a cluster is in the form of a diffuse hot gas in between the galaxies. This gas has a temperature of the order of several tens of million degrees and a density of the order of one atom per liter. At such high temperatures, it produces powerful X-ray emission. Observing this intergalactic gas and not just the individual galaxies is like seeing the buildings of a city in daytime, not just the lighted windows at night. This is why clusters of galaxies are best discovered using X-ray satellites. Using previous X-ray satellites, astronomers have performed limited studies of the large-scale structure of the nearby Universe. However, they so far lacked the instruments to extend the search to large volumes of the distant Universe. The XMM-Newton wide-field observations ESO PR Photo 19a/03 ESO PR Photo 19a/03 [Preview - JPEG: 575 x 400 pix - 52k [Normal - JPEG: 1130 x 800 pix - 420k] ESO PR Photo 19b/03 ESO PR Photo 19b/03 [Preview - JPEG: 400 x 489 pix - 52k [Normal - JPEG: 800 x 978 pix - 464k] Captions: PR Photo 19a/03 is the first image from the XMM-LSS X-Ray survey. It is actually a combination of fourteen separate "pointings" of this space observatory. It represents a region of the sky eight times larger than the full Moon and contains around 25 clusters. The circles represent the X-Ray sources previously known from the 1991 ROSAT All-Sky Survey. PR Photo 19b/03 zooms in on a particularly interesting region of the image shown in ESO PR Photo 19a/03 with a possible cluster identified (in box). Each point on this graph represents a single X-ray photon detected by XMM-Newton. Marguerite Pierre (CEA Saclay, France), with a European/Chilean team of astronomers known as the XMM-LSS consortium [2], used the large field-of-view and the high sensitivity of ESA's X-ray observatory XMM-Newton to search for remote clusters of galaxies and map out their distribution in space. They could see back about 7,000 million years to a cosmological era when the Universe was about half its present size and age, when clusters of galaxies were more tightly packed. Tracking down the clusters is a painstaking, multi-step process, requiring both space and ground-based telescopes. Indeed, from X-ray images with XMM, it was possible to select several tens of cluster candidate objects, identified as areas of enhanced X-radiation (cf PR Photo 19b/03). But having candidates is not enough ! They must be confirmed and further studied with ground-based telescopes. In tandem with XMM-Newton, Pierre uses the very-wide-field imager attached to the 4-m Canada-France-Hawaii Telescope, on Mauna Kea, Hawaii, to take an optical snapshot of the same region of space. A tailor-made computer programme then combs the XMM-Newton data looking for concentrations of X-rays that suggest large, extended structures. These are the clusters and represent only about 10% of the detected X-ray sources. The others are mostly distant active galaxies. Back to the Ground ESO PR Photo 19c/03 ESO PR Photo 19c/03 [Preview - JPEG: 400 x 481 pix - 84k [Normal - JPEG: 800 x 961 pix - 1M] ESO PR Photo 19d/03 ESO PR Photo 19d/03 [Preview - JPEG: 400 x 488 pix - 44k [Normal - JPEG: 800 x 976 pix - 520k] Captions: PR Photo 19c/03 represents the XMM-Newton X-ray contour map of the cluster's probable extent superimposed upon the CFHT I-band image. A concentration of distant galaxies is conspicuous, thus confirming the X-ray detection. The symbols indicate the galaxies which have been subject to a subsequent spectroscopic measurement and found to be cluster members (triangles flag emission line galaxies). The individual galaxies in the cluster can then be targeted for further observations with ESO's VLT, in order to measure its distance and locate the cluster in the universe. Following the X-ray discovery and the optical cluster identification, galaxies in the cluster field shown in ESO PR Photo 19c/03 have been spectroscopically observed at the ESO VLT using the FORS2 instrument in order to determine the cluster redshift [3]. Using two masks, each of them observed during one hour, allowing to take the spectra of 16 emission-line galaxies at a time, the cluster was found to have a redshift of 0.84, corresponding to a distance of 8,000 million light-years, and a velocity dispersion of 750 km/s. PR Photo 19d/03 shows the measured velocity distribution. This is one of the most distant known clusters of galaxies for which a velocity dispersion has been measured. When the programme finds a cluster, it zooms in on that region and converts the XMM-Newton data into a contour map of X-ray intensity, which is then superimposed upon the CFHT optical image (PR Photo 19c/03). The astronomers use this to check if anything is visible within the area of extented X-ray emission. If something is seen, the work then shifts to one of the world's prime optical/infrared telescopes, the European Southern Observatory's Very Large Telescope (VLT) at Paranal (Chile). By means of the FORS multi-mode instruments, the astronomers zoom-in on the individual galaxies in the field, taking spectral measurements that reveal their overall characteristics, in particular their redshift and hence, distance. Cluster galaxies have similar distances and these measurement ultimately provide, by averaging, the cluster's distance as well as the velocity dispersion in the cluster. The FORS instruments are among the most efficient and versatile for this type of work, taking on the average spectra of 30 galaxies at a time. The first spectroscopic observations dedicated to the identification and redshift measurement of the XMM-LSS galaxy clusters took place during three nights in the fall of 2002. As of March 2003, there were only 5 known clusters in the literature at such a large redshift with enough spectroscopically measured redshifts to allow an estimate of the velocity dispersion. But the VLT allowed obtaining the dispersion in a distant cluster in 2 hours only, raising great expectations for future work. 700 spectra... Marguerite Pierre is extremely content : Weather and working conditions at the VLT were optimal. In three nights only, 12 cluster fields were observed, yielding no less than 700 spectra of galaxies. The overall strategy proved very successful. The high observing efficiency of the VLT and FORS support our plan to perform follow-up studies of large numbers of distant clusters with relatively little observing time. This represents a most substantial increase in efficiency compared to former searches. The present research programme has begun well, clearly demonstrating the feasibility of this new multi-telescope approach and its very high efficiency. And Marguerite Pierre and her colleagues are already seeing the first tantalising results: it seems to confirm that the number of clusters 7,000 million years ago is little different from that of today. This particular behaviour is predicted by models of the Universe that expand forever, driving the galaxy clusters further and further apart. Equally important, this multi-wavelength, multi-telescope approach developed by the XMM-LSS consortium to locate clusters of galaxies also constitutes a decisive next step in the fertile synergy between space and ground-based observatories and is therefore a basic building block of the forthcoming Virtual Observatory. More information This work is based on two papers to be published in the professional astronomy journal, Astronomy and Astrophysics (The XMM-LSS survey : I. Scientific motivations, design and first results by Marguerite Pierre et al., astro-ph/0305191 and The XMM-LSS survey : II. First high redshift galaxy clusters: relaxed and collapsing systems by Ivan Valtchanov et al., astro-ph/0305192). Dr. M. Pierre will give an invited talk on this subject at the IAU Symposium 216 - Maps of the Cosmos - this Thursday July 17, 2003 during the IAU General Assembly 2003 in Sydney, Australia.

Integrated spectral properties of 7 galactic open clusters

NASA Astrophysics Data System (ADS)

Ahumada, A. V.; Clariá, J. J.; Bica, E.; Piatti, A. E.

2000-01-01

This paper presents flux-calibrated integrated spectra in the range 3600-9000 Ä for 7 concentrated, relatively populous Galactic open clusters. We perform simultaneous estimates of age and foreground interstellar reddening by comparing the continuum distribution and line strengths of the cluster spectra with those of template cluster spectra with known parameters. For five clusters these two parameters have been determined for the first time (Ruprecht 144, BH 132, Pismis 21, Lyng\\aa 11 and BH 217), while the results here derived for the remaining two clusters (Hogg 15 and Melotte 105) show very good agreement with previous studies based mainly on colour-magnitude diagrams. We also provide metallicity estimates for six clusters from the equivalent widths of CaII triplet and TiO features. The present cluster sample improves the age resolution around solar metal content in the cluster spectral library for population synthesis. We compare the properties of the present sample with those of clusters in similar directions. Hogg 15 and Pismis 21 are among the most reddened clusters in sectors centered at l = 270o and l = 0o, respectively. Besides, the present results would favour an important dissolution rate of star clusters in these zones. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan, Argentina.

Development of the CoMac Adherence Descriptor™: a linguistically-based survey for segmenting patients on their worldviews

PubMed Central

Connor, Ulla M; Mac Neill, Robert S; Mzumara, Howard R; Sandy, Robert

2015-01-01

Nonadherence to prescribed medication and healthy behaviors is a pressing health care issue. Much research has been conducted in this area under a variety of labels, such as compliance, disease management and, most recently, adherence. However, the complex factors related to predicting and, more importantly, understanding and explaining adherence, have nevertheless remained elusive. However, through an in-depth linguistic analysis of patient talk, the International Center for Intercultural Communication (ICIC) at Indiana University has produced a psycholinguistic coding system that uses patients’ own language to cluster them into distinct groups based on their worldviews. ICIC’s studies have shown, for example, that patients reveal their fundamental perceptions about themselves and their environment in their life narratives; clustering of individual patients based on these different perceptions is possible via the use of differential language in survey questions, and differential language can be used to tailor messages for individual patients in a manner that these individuals prefer over generically worded communication. In grant-funded research, an interdisciplinary team of researchers at the ICIC reviewed the literature and identified three basic psychosocial tenets related to adherence: control orientation, based on locus of control research; agency, based on self-efficacy; and affect or attitude and emotion. These three constructs were selected because, in the published literature, they have been consistently found to be connected to patient adherence. Based on this research, a survey, the CoMac Descriptor™ was developed. This report shows that The Descriptor™ questions and responses are valid and reliable in segmenting patients across psychosocial constructs, which will have positive implications for health care providers and patients. PMID:25848230

Exact hierarchical clustering in one dimension. [in universe

NASA Technical Reports Server (NTRS)

Williams, B. G.; Heavens, A. F.; Peacock, J. A.; Shandarin, S. F.

1991-01-01

The present adhesion model-based one-dimensional simulations of gravitational clustering have yielded bound-object catalogs applicable in tests of analytical approaches to cosmological structure formation. Attention is given to Press-Schechter (1974) type functions, as well as to their density peak-theory modifications and the two-point correlation function estimated from peak theory. The extent to which individual collapsed-object locations can be predicted by linear theory is significant only for objects of near-characteristic nonlinear mass.

Effects of community health interventions on under-5 mortality in rural Guinea-Bissau (EPICS): a cluster-randomised controlled trial.

PubMed

Boone, Peter; Elbourne, Diana; Fazzio, Ila; Fernandes, Samory; Frost, Chris; Jayanty, Chitra; King, Rebecca; Mann, Vera; Piaggio, Gilda; dos Santos, Albino; Walker, Polly R

2016-05-01

Evidence suggests that community-based interventions that promote improved home-based practices and care-seeking behaviour can have a large impact on maternal and child mortality in regions where rates are high. We aimed to assess whether an intervention package based on the WHO Integrated Management of Childhood Illness handbook and community mobilisation could reduce under-5 mortality in rural Guinea-Bissau, where the health service infrastructure is weak. We did a non-masked cluster-randomised controlled trial (EPICS) in the districts of Tombali and Quinara in Guinea-Bissau. Clusters of rural villages were stratified by ethnicity and distance from a regional health centre, and randomly assigned (1:1) to intervention or control using a computerised random number generator. Women were eligible if they lived in one of the clusters at baseline survey prior to randomisation and if they were aged 15-49 years or were primary caregivers of children younger than 5 years. Their children were eligible if they were younger than 5 years or were liveborn after intervention services could be implemented on July 1, 2008. In villages receiving the intervention, community health clubs were established, community health workers were trained in case management, and traditional birth attendants were trained to care for pregnant women and newborn babies, and promote facility-based delivery. Registered nurses supervised community health workers and offered mobile clinic services. Health centres were not improved. The control group received usual services. The primary outcome was the proportion of children dying under age 5 years, and was analysed in all eligible children up to final visits to villages between Jan 1 and March 31, 2011. This trial is registered with ISRCTN, number ISRCTN52433336. On Aug 30, 2007, we randomly assigned 146 clusters to intervention (73 clusters, 5669 women, and 4573 children) or control (73 clusters, 5840 women, and 4675 children). From randomisation until the end of the trial (last visit by June 30, 2011), the intervention clusters had 3093 livebirths and the control clusters had 3194. 6729 children in the intervention group and 6894 in the control group aged 0-5 years on July 1, 2008, or liveborn subsequently were analysed for mortality outcomes. 311 (4·6%) of 6729 children younger than 5 years died in the intervention group compared with 273 (4·0%) of 6894 in the control group (relative risk 1·16 [95% CI 0·99-1·37]). Our package of community-based interventions did not reduce under-5 mortality in rural Guinea-Bissau. The short timeframe and other trial limitations might have affected our results. Community-based health promotion and basic first-line services in fragile contexts with weak secondary health service infrastructure might be insufficient to reduce child deaths. Effective Intervention. Copyright © 2016 Boone et al. Open Access article distributed under the terms of CC BY-NC-ND. Published by Elsevier Ltd.. All rights reserved.

Integrating Data Clustering and Visualization for the Analysis of 3D Gene Expression Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Data Analysis and Visualization; nternational Research Training Group ``Visualization of Large and Unstructured Data Sets,'' University of Kaiserslautern, Germany; Computational Research Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA

2008-05-12

The recent development of methods for extracting precise measurements of spatial gene expression patterns from three-dimensional (3D) image data opens the way for new analyses of the complex gene regulatory networks controlling animal development. We present an integrated visualization and analysis framework that supports user-guided data clustering to aid exploration of these new complex datasets. The interplay of data visualization and clustering-based data classification leads to improved visualization and enables a more detailed analysis than previously possible. We discuss (i) integration of data clustering and visualization into one framework; (ii) application of data clustering to 3D gene expression data; (iii)more » evaluation of the number of clusters k in the context of 3D gene expression clustering; and (iv) improvement of overall analysis quality via dedicated post-processing of clustering results based on visualization. We discuss the use of this framework to objectively define spatial pattern boundaries and temporal profiles of genes and to analyze how mRNA patterns are controlled by their regulatory transcription factors.« less

Surprise Discovery of Highly Developed Structure in the Young Universe

NASA Astrophysics Data System (ADS)

2005-03-01

ESO-VLT and ESA XMM-Newton Together Discover Earliest Massive Cluster of Galaxies Known Summary Combining observations with ESO's Very Large Telescope and ESA's XMM-Newton X-ray observatory, astronomers have discovered the most distant, very massive structure in the Universe known so far. It is a remote cluster of galaxies that is found to weigh as much as several thousand galaxies like our own Milky Way and is located no less than 9,000 million light-years away. The VLT images reveal that it contains reddish and elliptical, i.e. old, galaxies. Interestingly, the cluster itself appears to be in a very advanced state of development. It must therefore have formed when the Universe was less than one third of its present age. The discovery of such a complex and mature structure so early in the history of the Universe is highly surprising. Indeed, until recently it would even have been deemed impossible. PR Photo 05a/05: Discovery X-Ray Image of the Distant Cluster (ESA XMM-Netwon) PR Photo 05b/05: False Colour Image of XMMU J2235.3-2557 (FORS/VLT and ESA XMM-Newton) Serendipitous discovery ESO PR Photo 05a/05 ESO PR Photo 05a/05 Discovery X-Ray Image of the Distant Cluster (ESA XMM-Newton) [Preview - JPEG: 400 x 421 pix - 106k] [Normal - JPEG: 800 x 842 pix - 843k] [Full Res - JPEG: 2149 x 2262 pix - 2.5M] Caption: ESO PR Photo 05a/05 is a reproduction of the XMM-Newton observations of the nearby active galaxy NGC7314 (bright object in the centre) from which the newly found distant cluster (white box) was serendipitously identified. The circular field-of-view of XMM-Newton is half-a-degree in diameter, or about the same angular size as the Full Moon. The inset shows the diffuse X-ray emission from the distant cluster XMMU J2235.3-2557. Clusters of galaxies are gigantic structures containing hundreds to thousands of galaxies. They are the fundamental building blocks of the Universe and their study thus provides unique information about the underlying architecture of the Universe as a whole. About one-fifth of the optically invisible mass of a cluster is in the form of a diffuse, very hot gas with a temperature of several tens of millions of degrees. This gas emits powerful X-ray radiation and clusters of galaxies are therefore best discovered by means of X-ray satellites (cf. ESO PR 18/03 and 15/04). It is for this reason that a team of astronomers [1] has initiated a search for distant, X-ray luminous clusters "lying dormant" in archive data from ESA's XMM-Newton satellite observatory. Studying XMM-Newton observations targeted at the nearby active galaxy NGC 7314, the astronomers found evidence of a galaxy cluster in the background, far out in space. This source, now named XMMU J2235.3-2557, appeared extended and very faint: no more than 280 X-ray photons were detected over the entire 12 hour-long observations. A Mature Cluster at Redshift 1.4 ESO PR Photo 05b/05 ESO PR Photo 05b/05 False Colour Image of XMMU J2235.3-2557 (FORS/VLT and ESA XMM-Newton) [Preview - JPEG: 400 x 455 pix - 50k] [Normal - JPEG: 800 x 909 pix - 564k] [Full Res - JPEG: 1599 x 1816 pix - 1.5M] Caption: ESO PR Photo 05b/05 is a false colour image of the XMMU J2235.3-2557 cluster of galaxies, overlaid with the X-ray intensity contours derived from the ESA XMM-Newton data. The red channel is a VLT-ISAAC image (exposure time: 1 hour) obtained in the near-infrared Ks-band (at wavelength 2.2 microns); the green channel is a VLT-FORS2 z-band image (910 nm; 480 sec); the blue channel is a VLT-FORS2 R-band image (; 657 nm; 1140 sec). The VLT reveals 12 reddish galaxies, of elliptical types, as members of the cluster. Knowing where to look, the astronomers then used the European Southern Observatory's Very Large Telescope (VLT) at Paranal (Chile) to obtain images in the visible wavelength region. They confirmed the nature of this cluster and it was possible to identify 12 comparatively bright member galaxies on the images (see ESO PR Photo 05b/05). The galaxies appear reddish and are of the elliptical type. They are full of old, red stars. All of this indicates that these galaxies are already several thousand million years old. Moreover, the cluster itself has a largely spherical shape, also a sign that it is already a very mature structure. In order to determine the distance of the cluster - and hence its age - Christopher Mullis, former European Southern Observatory post-doctoral fellow and now at the University of Michigan in the USA, and his colleagues used again the VLT, now in the spectroscopic mode. By means of one of the FORS multi-mode instruments, the astronomers zoomed-in on the individual galaxies in the field, taking spectral measurements that reveal their overall characteristics, in particular their redshift and hence, distance [2]. The FORS instruments are among the most efficient and versatile available anywhere for this delicate work, obtaining on the average quite detailed spectra of 30 or more galaxies at a time. The VLT data measured the redshift of this cluster as 1.4, indicating a distance of 9,000 million light-years, 500 million light years farther out than the previous record holding cluster. This means that the present cluster must have formed when the Universe was less than one third of its present age. The Universe is now believed to be 13,700 million years old. "We are quite surprised to see that a fully-fledged structure like this could exist at such an early epoch," says Christopher Mullis. "We see an entire network of stars and galaxies in place, just a few thousand million years after the Big Bang". "We seem to have underestimated how quickly the early Universe matured into its present-day state," adds Piero Rosati of ESO, another member of the team. "The Universe did grow up fast!" Towards a Larger Sample This discovery was relative easy to make, once the space-based XMM and the ground-based VLT observations were combined. As an impressive result of the present pilot programme that is specifically focused on the identification of very distant galaxy clusters, it makes the astronomers very optimistic about their future searches. The team is now carrying out detailed follow-up observations both from ground- and space-based observatories. They hope to find many more exceedingly distant clusters, which would then allow them to test competing theories of the formation and evolution of such large structures. "This discovery encourages us to search for additional distant clusters by means of this very efficient technique," says Axel Schwope, team leader at the Astrophysical Institute Potsdam (Germany) and responsible for the source detection from the XMM-Newton archival data. Hans Böhringer of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, another member of the team, adds: "Our result also confirms the great promise inherent in other facilities to come, such as APEX (Atacama Pathfinder Experiment) at Chajnantor, the site of the future Atacama Large Millimeter Array. These intense searches will ultimately place strong constraints on some of the most fundamental properties of the Universe." More information This finding is presented today by Christopher Mullis at a scientific meeting in Kona, Hawaii, entitled "The Future of Cosmology with Clusters of Galaxies". It will also soon appear in The Astrophysical Journal ("Discovery of an X-ray Luminous Galaxy Cluster at z=1.4", by C. R. Mullis et al.). More images and information is available on Christopher Mullis' dedicated web page at http://www.astro.lsa.umich.edu/~cmullis/research/xmmuj2235/. A German version of the press release is issued by the Max Planck Society and is available at http://www.mpg.de/bilderBerichteDokumente/dokumentation/pressemitteilungen/2005/pressemitteilung20050228/presselogin/ .

Measuring Systemic and Climate Diversity in Ontario's University Sector

ERIC Educational Resources Information Center

Piché, Pierre Gilles

2015-01-01

This article proposes a methodology for measuring institutional diversity and applies it to Ontario's university sector. This study first used hierarchical cluster analysis, which suggested there has been very little change in diversity between 1994 and 2010 as universities were clustered in three groups for both years. However, by adapting…

Beam Design and User Scheduling for Nonorthogonal Multiple Access With Multiple Antennas Based on Pareto Optimality

NASA Astrophysics Data System (ADS)

Seo, Junyeong; Sung, Youngchul

2018-06-01

In this paper, an efficient transmit beam design and user scheduling method is proposed for multi-user (MU) multiple-input single-output (MISO) non-orthogonal multiple access (NOMA) downlink, based on Pareto-optimality. The proposed beam design and user scheduling method groups simultaneously-served users into multiple clusters with practical two users in each cluster, and then applies spatical zeroforcing (ZF) across clusters to control inter-cluster interference (ICI) and Pareto-optimal beam design with successive interference cancellation (SIC) to two users in each cluster to remove interference to strong users and leverage signal-to-interference-plus-noise ratios (SINRs) of interference-experiencing weak users. The proposed method has flexibility to control the rates of strong and weak users and numerical results show that the proposed method yields good performance.

Chandra Opens New Line of Investigation on Dark Energy

NASA Astrophysics Data System (ADS)

2004-05-01

Astronomers have detected and probed dark energy by applying a powerful, new method that uses images of galaxy clusters made by NASA's Chandra X-ray Observatory. The results trace the transition of the expansion of the Universe from a decelerating to an accelerating phase several billion years ago, and give intriguing clues about the nature of dark energy and the fate of the Universe. "Dark energy is perhaps the biggest mystery in physics," said Steve Allen of the Institute of Astronomy (IoA) at the University of Cambridge in England, and leader of the study. "As such, it is extremely important to make an independent test of its existence and properties." Abell 2029 Chandra X-ray Image of Abell 2029 Allen and his colleagues used Chandra to study 26 clusters of galaxies at distances corresponding to light travel times of between one and eight billion years. These data span the time when the Universe slowed from its original expansion, before speeding up again because of the repulsive effect of dark energy. "We're directly seeing that the expansion of the Universe is accelerating by measuring the distances to these galaxy clusters," said Andy Fabian also of the IoA, a co-author on the study. The new Chandra results suggest that the dark energy density does not change quickly with time and may even be constant, consistent with the "cosmological constant" concept first introduced by Albert Einstein. If so, the Universe is expected to continue expanding forever, so that in many billions of years only a tiny fraction of the known galaxies will be observable. More Animations Animation of the "Big Rip" If the dark energy density is constant, more dramatic fates for the Universe would be avoided. These include the "Big Rip," where dark energy increases until galaxies, stars, planets and eventually atoms are eventually torn apart. The "Big Crunch," where the Universe eventually collapses on itself, would also be ruled out. Chandra's probe of dark energy relies on the unique ability of X-ray observations to detect and study the hot gas in galaxy clusters. From these data, the ratio of the mass of the hot gas and the mass of the dark matter in a cluster can be determined. The observed values of the gas fraction depend on the assumed distance to the cluster, which in turn depends on the curvature of space and the amount of dark energy in the universe. Galaxy Cluster Animation Galaxy Cluster Animation Because galaxy clusters are so large, they are thought to represent a fair sample of the matter content in the universe. If so, then relative amounts of hot gas and dark matter should be the same for every cluster. Using this assumption, Allen and colleagues adjusted the distance scale to determine which one fit the data best. These distances show that the expansion of the Universe was first decelerating and then began to accelerate about six billion years ago. Chandra's observations agree with supernova results including those from the Hubble Space Telescope (HST), which first showed dark energy's effect on the acceleration of the Universe. Chandra's results are completely independent of the supernova technique - both in wavelength and the objects observed. Such independent verification is a cornerstone of science. In this case it helps to dispel any remaining doubts that the supernova technique is flawed. "Our Chandra method has nothing to do with other techniques, so they're definitely not comparing notes, so to speak," said Robert Schmidt of University of Potsdam in Germany, another coauthor on the study. Energy Distribution of the Universe Energy Distribution of the Universe Better limits on the amount of dark energy and how it varies with time are obtained by combining the X-ray results with data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP), which used observations of the cosmic microwave background radiation to discover evidence for dark energy in the very early Universe. Using the combined data, Allen and his colleagues found that dark energy makes up about 75% of the Universe, dark matter about 21%, and visible matter about 4%. Allen and his colleagues stress that the uncertainties in the measurements are such that the data are consistent with dark energy having a constant value. The present Chandra data do, however, allow for the possibility that the dark energy density is increasing with time. More detailed studies with Chandra, HST, WMAP and with the future mission Constellation-X should provide much more precise constraints on dark energy. Expansion of the Universe Expansion of the Universe at Constant Acceleration "Until we better understand cosmic acceleration and the nature of the dark energy we cannot hope to understand the destiny of the Universe," said independent commentator Michael Turner, of the University of Chicago. The team conducting the research also included Harald Ebeling of the University of Hawaii and the late Leon van Speybroeck of the Harvard-Smithsonian Center for Astrophysics. These results will appear in an upcoming issue of the Monthly Notices of the Royal Astronomy Society. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA's Office of Space Science, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Press Kit: Galaxy Clusters and Dark Energy Press Kit Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

Camino Verde (The Green Way): evidence-based community mobilisation for dengue control in Nicaragua and Mexico: feasibility study and study protocol for a randomised controlled trial.

PubMed

Andersson, Neil; Arostegui, Jorge; Nava-Aguilera, Elizabeth; Harris, Eva; Ledogar, Robert J

2017-05-30

Since the Aedes aegypti mosquitoes that transmit dengue virus can breed in clean water, WHO-endorsed vector control strategies place sachets of organophosphate pesticide, temephos (Abate), in household water storage containers. These and other pesticide-dependent approaches have failed to curb the spread of dengue and multiple dengue virus serotypes continue to spread throughout tropical and subtropical regions worldwide. A feasibility study in Managua, Nicaragua, generated instruments, intervention protocols, training schedules and impact assessment tools for a cluster randomised controlled trial of community-based approaches to vector control comprising an alternative strategy for dengue prevention and control in Nicaragua and Mexico. The Camino Verde (Green Way) is a pragmatic parallel group trial of pesticide-free dengue vector control, adding effectiveness to the standard government dengue control. A random sample from the most recent census in three coastal regions of Guerrero state in Mexico will generate 90 study clusters and the equivalent sampling frame in Managua, Nicaragua will generate 60 clusters, making a total of 150 clusters each of 137-140 households. After a baseline study, computer-driven randomisation will allocate to intervention one half of the sites, stratified by country, evidence of recent dengue virus infection in children aged 3-9 years and, in Nicaragua, level of community organisation. Following a common evidence-based education protocol, each cluster will develop and implement its own collective interventions including house-to-house visits, school-based programmes and inter-community visits. After 18 months, a follow-up study will compare dengue history, serological evidence of recent dengue virus infection (via measurement of anti-dengue virus antibodies in saliva samples) and entomological indices between intervention and control sites. Our hypothesis is that informed community mobilisation adds effectiveness in controlling dengue. ISRCTN27581154 .

HICOSMO - X-ray analysis of a complete sample of galaxy clusters

NASA Astrophysics Data System (ADS)

Schellenberger, G.; Reiprich, T.

2017-10-01

Galaxy clusters are known to be the largest virialized objects in the Universe. Based on the theory of structure formation one can use them as cosmological probes, since they originate from collapsed overdensities in the early Universe and witness its history. The X-ray regime provides the unique possibility to measure in detail the most massive visible component, the intra cluster medium. Using Chandra observations of a local sample of 64 bright clusters (HIFLUGCS) we provide total (hydrostatic) and gas mass estimates of each cluster individually. Making use of the completeness of the sample we quantify two interesting cosmological parameters by a Bayesian cosmological likelihood analysis. We find Ω_{M}=0.3±0.01 and σ_{8}=0.79±0.03 (statistical uncertainties) using our default analysis strategy combining both, a mass function analysis and the gas mass fraction results. The main sources of biases that we discuss and correct here are (1) the influence of galaxy groups (higher incompleteness in parent samples and a differing behavior of the L_{x} - M relation), (2) the hydrostatic mass bias (as determined by recent hydrodynamical simulations), (3) the extrapolation of the total mass (comparing various methods), (4) the theoretical halo mass function and (5) other cosmological (non-negligible neutrino mass), and instrumental (calibration) effects.

Fundamental parameters of the highly reddened young open clusters Westerlund 1 and 2

NASA Astrophysics Data System (ADS)

Piatti, A. E.; Bica, E.; Claria, J. J.

1998-02-01

We study the compact open clusters Westerlund1 (BH197) and Westerlund2. We present CCD integrated spectroscopy for both clusters, and CCD imaging in the V and I bands for the former one. So far, Westerlund1 is possibly the most reddened open cluster studied in detail (Av ~ 13.0). It has an age of 8 +/- 3 Myr and a distance from the Sun of d_sun ~ 1.0 +/- 0.4 kpc. For Westerlund2 we derive a visual absorption AV~ 5.0 mag, an age of 2-3 Myr, and d_sun=5.7+/- 0.3 kpc. From luminosity and structural arguments we conclude that Westerlund1, although young and compact, it is a massive cluster, in contrast to Westerlund2. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina and the Universities of La Plata, Cordoba and San Juan, Argentina, and at the University of Toronto (David Dunlap Observatory) 24-inch telescope, Las Campanas, Chile. The photometric observations are available at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Evaluating the Implementation of a School-Based Emotional Well-Being Programme: A Cluster Randomized Controlled Trial of Zippy's Friends for Children in Disadvantaged Primary Schools

ERIC Educational Resources Information Center

Clarke, Aleisha M.; Bunting, Brendan; Barry, Margaret M.

2014-01-01

Schools are recognized as one of the most important settings for promoting social and emotional well-being among children and adolescents. This clustered randomized controlled trial evaluated Zippy's Friends, an international school-based emotional well-being programme, with 766 children from designated disadvantaged schools. The purpose of this…

GALAXIES IN THE YOUNG UNIVERSE [left

NASA Technical Reports Server (NTRS)

2002-01-01

This image of a small region of the constellation Sculptor, taken with a ground-based photographic sky survey camera, illustrates the extremely small angular size of a distant galaxy cluster in the night sky. Though this picture encompasses a piece of the sky about the width of the bowl of the Big Dipper, the cluster is so far away it fills a sky area only 1/10th the diameter of the Full Moon. The cluster members are not visible because they are so much fainter than foreground stars. [center] A NASA Hubble Space Telescope (HST) image of the farthest cluster of galaxies in the universe, located at a distance of 12 billion light-years. Because the light from these remote galaxies has taken 12 billion years to reach us, this image is a remarkable glimpse of the primeval universe, at it looked about two billion years after the Big Bang. The cluster contains 14 galaxies, the other objects are largely foreground galaxies. The galaxy cluster lies in front of quasar Q0000-263 in the constellation Sculptor. Presumably the brilliant core of an active galaxy, the quasar provides a beacon for searching for primordial galaxy clusters. The image is the full field view of the Wide Field and Planetary Camera-2, taken on September 6, 1994. The 4.7-hour exposure reveals objects down to 28.5 magnitude. [right] This enlargement shows one of the farthest normal galaxies yet detected, (blob at center right) at a distance of 12 billion light-years (redshift of z=3.330). The galaxy lies 300 million light-years in front of the quasar Q0000-263 (z=4.11, large white blob and spike on left side of frame) and was detected because it absorbs some light from the quasar. The galaxy's spectrum reveals that vigorous star formation is taking place. Credit: Duccio Macchetto (ESA/STScI), Mauro Giavalisco (STScI), and NASA

X-ray clusters from a high-resolution hydrodynamic PPM simulation of the cold dark matter universe

NASA Technical Reports Server (NTRS)

Bryan, Greg L.; Cen, Renyue; Norman, Michael L.; Ostriker, Jermemiah P.; Stone, James M.

1994-01-01

A new three-dimensional hydrodynamic code based on the piecewise parabolic method (PPM) is utilized to compute the distribution of hot gas in the standard Cosmic Background Explorer (COBE)-normalized cold dark matter (CDM) universe. Utilizing periodic boundary conditions, a box with size 85 h(exp-1) Mpc, having cell size 0.31 h(exp-1) Mpc, is followed in a simulation with 270(exp 3)=10(exp 7.3) cells. Adopting standard parameters determined from COBE and light-element nucleosynthesis, Sigma(sub 8)=1.05, Omega(sub b)=0.06, we find the X-ray-emitting clusters, compute the luminosity function at several wavelengths, the temperature distribution, and estimated sizes, as well as the evolution of these quantities with redshift. The results, which are compared with those obtained in the preceding paper (Kang et al. 1994a), may be used in conjuction with ROSAT and other observational data sets. Overall, the results of the two computations are qualitatively very similar with regard to the trends of cluster properties, i.e., how the number density, radius, and temeprature depend on luminosity and redshift. The total luminosity from clusters is approximately a factor of 2 higher using the PPM code (as compared to the 'total variation diminishing' (TVD) code used in the previous paper) with the number of bright clusters higher by a similar factor. The primary conclusions of the prior paper, with regard to the power spectrum of the primeval density perturbations, are strengthened: the standard CDM model, normalized to the COBE microwave detection, predicts too many bright X-ray emitting clusters, by a factor probably in excess of 5. The comparison between observations and theoretical predictions for the evolution of cluster properties, luminosity functions, and size and temperature distributions should provide an important discriminator among competing scenarios for the development of structure in the universe.

A Unique Sample of Extreme-BCG Clusters at 0.2 < z < 0.5

NASA Astrophysics Data System (ADS)

Garmire, Gordon

2017-09-01

The recently-discovered Phoenix cluster harbors the most extreme BCG in the known universe. Despite the cluster's high mass and X-ray luminosity, it was consistently identified by surveys as an isolated AGN, due to the bright central point source and the compact cool core. Armed with hindsight, we have undertaken an all-sky survey based on archival X-ray, OIR, and radio data to identify other similarly-extreme systems that were likewise missed. A pilot study demonstrated that this strategy works, leading to the discovery of a new, massive cluster at z 0.2 which was missed by previous X-ray surveys due to the presence of a bright central QSO. We propose here to observe 6 new clusters from our complete northern-sky survey, which harbor some of the most extreme central galaxies known.

Distant Massive Clusters and Cosmology

NASA Technical Reports Server (NTRS)

Donahue, Megan

1999-01-01

We present a status report of our X-ray study and analysis of a complete sample of distant (z=0.5-0.8), X-ray luminous clusters of galaxies. We have obtained ASCA and ROSAT observations of the five brightest Extended Medium Sensitivity (EMSS) clusters with z > 0.5. We have constructed an observed temperature function for these clusters, and measured iron abundances for all of these clusters. We have developed an analytic expression for the behavior of the mass-temperature relation in a low-density universe. We use this mass-temperature relation together with a Press-Schechter-based model to derive the expected temperature function for different values of Omega-M. We combine this analysis with the observed temperature functions at redshifts from 0 - 0.8 to derive maximum likelihood estimates for the value of Omega-M. We report preliminary results of this analysis.

A Web-Based Multidrug-Resistant Organisms Surveillance and Outbreak Detection System with Rule-Based Classification and Clustering

PubMed Central

Tseng, Yi-Ju; Wu, Jung-Hsuan; Ping, Xiao-Ou; Lin, Hui-Chi; Chen, Ying-Yu; Shang, Rung-Ji; Chen, Ming-Yuan; Lai, Feipei

2012-01-01

Background The emergence and spread of multidrug-resistant organisms (MDROs) are causing a global crisis. Combating antimicrobial resistance requires prevention of transmission of resistant organisms and improved use of antimicrobials. Objectives To develop a Web-based information system for automatic integration, analysis, and interpretation of the antimicrobial susceptibility of all clinical isolates that incorporates rule-based classification and cluster analysis of MDROs and implements control chart analysis to facilitate outbreak detection. Methods Electronic microbiological data from a 2200-bed teaching hospital in Taiwan were classified according to predefined criteria of MDROs. The numbers of organisms, patients, and incident patients in each MDRO pattern were presented graphically to describe spatial and time information in a Web-based user interface. Hierarchical clustering with 7 upper control limits (UCL) was used to detect suspicious outbreaks. The system’s performance in outbreak detection was evaluated based on vancomycin-resistant enterococcal outbreaks determined by a hospital-wide prospective active surveillance database compiled by infection control personnel. Results The optimal UCL for MDRO outbreak detection was the upper 90% confidence interval (CI) using germ criterion with clustering (area under ROC curve (AUC) 0.93, 95% CI 0.91 to 0.95), upper 85% CI using patient criterion (AUC 0.87, 95% CI 0.80 to 0.93), and one standard deviation using incident patient criterion (AUC 0.84, 95% CI 0.75 to 0.92). The performance indicators of each UCL were statistically significantly higher with clustering than those without clustering in germ criterion (P < .001), patient criterion (P = .04), and incident patient criterion (P < .001). Conclusion This system automatically identifies MDROs and accurately detects suspicious outbreaks of MDROs based on the antimicrobial susceptibility of all clinical isolates. PMID:23195868

Benefits of off-campus education for students in the health sciences: a text-mining analysis.

PubMed

Nakagawa, Kazumasa; Asakawa, Yasuyoshi; Yamada, Keiko; Ushikubo, Mitsuko; Yoshida, Tohru; Yamaguchi, Haruyasu

2012-08-28

In Japan, few community-based approaches have been adopted in health-care professional education, and the appropriate content for such approaches has not been clarified. In establishing community-based education for health-care professionals, clarification of its learning effects is required. A community-based educational program was started in 2009 in the health sciences course at Gunma University, and one of the main elements in this program is conducting classes outside school. The purpose of this study was to investigate using text-analysis methods how the off-campus program affects students. In all, 116 self-assessment worksheets submitted by students after participating in the off-campus classes were decomposed into words. The extracted words were carefully selected from the perspective of contained meaning or content. With the selected terms, the relations to each word were analyzed by means of cluster analysis. Cluster analysis was used to select and divide 32 extracted words into four clusters: cluster 1-"actually/direct," "learn/watch/hear," "how," "experience/participation," "local residents," "atmosphere in community-based clinical care settings," "favorable," "communication/conversation," and "study"; cluster 2-"work of staff member" and "role"; cluster 3-"interaction/communication," "understanding," "feel," "significant/important/necessity," and "think"; and cluster 4-"community," "confusing," "enjoyable," "proactive," "knowledge," "academic knowledge," and "class." The students who participated in the program achieved different types of learning through the off-campus classes. They also had a positive impression of the community-based experience and interaction with the local residents, which is considered a favorable outcome. Off-campus programs could be a useful educational approach for students in health sciences.

A Distant, X-Ray Luminous Cluster of Galaxies at Redshift 0.83

NASA Technical Reports Server (NTRS)

Donahue, Megan

1999-01-01

We have observed the most distant (= 0.829) cluster of galaxies in the Einstein Extended Medium Sensitivity Survey (EMSS), with the ASCA and ROSAT satellites. We find an X-ray temperature of 12.3(sup 3.1, sub 2.2) keV for this cluster, and the ROSAT map reveals significant substructure. The high temperature of MS1054-0321 is consistent with both its approximate velocity dispersion, based on the redshifts of 12 cluster members we have obtained at the Keck and the Canada-France-Hawaii telescopes, and with its weak lensing signature. The X-ray temperature of this cluster implies a virial mass approximately 7.4 x 10(exp 14) /h solar mass, if the mean matter density in the universe equals the critical value (OMEGA(sub 0) = 1), or larger if OMEGA(sub 0) < 1. Finding such a hot, massive cluster in the EMSS is extremely improbable if clusters grew from Gaussian perturbations in an OMEGA(sub 0) = 1 universe. Combining the assumptions that OMEGA(sub 0) = 1 and that the initial perturbations were Gaussian with the observed X-ray temperature function at low redshift, we show that this probability of this cluster occurring in the volume sampled by the EMSS is less than a few times 10(exp -5). Nor is MS1054-0321 the only hot cluster at high redshift; the only two other z > 0.5 EMSS clusters already observed with ASCA also have temperatures exceeding 8 keV. Assuming again that the initial perturbations were Gaussian and OMEGA(sub 0) = 1, we find that each one is improbable at the < 10(exp -2) level. These observations, along with the fact that these luminosities and temperatures of the high-z clusters all agree with the low-z L(sub x) - T(sub x) relation, argue strongly that OMEGA(sub 0) < 1. Otherwise, the initial perturbations must be non-Gaussian, if these clusters' temperatures do indeed reflect their gravitational potentials.

Trial for the Prevention of Depression (TriPoD) in final-year secondary students: study protocol for a cluster randomised controlled trial.

PubMed

Perry, Yael; Calear, Alison L; Mackinnon, Andrew; Batterham, Philip J; Licinio, Julio; King, Catherine; Thomsen, Noel; Scott, Jan; Donker, Tara; Merry, Sally; Fleming, Theresa; Stasiak, Karolina; Werner-Seidler, Aliza; Christensen, Helen

2015-10-12

Evidence suggests that current treatments cannot fully alleviate the burden of disease associated with depression but that prevention approaches offer a promising opportunity to further reduce this burden. Adolescence is a critical period in the development of mental illness, and final school examinations are a significant and nearly universal stressor that may act as a trigger for mental health difficulties such as depression. The aim of the present trial is to investigate the impact of SPARX-R, an online, gamified intervention based on cognitive behavioural principles, on the prevention of depression in secondary school students before their final examinations. Government, independent and Catholic secondary schools in New South Wales, Australia, will be recruited to participate in the trial. All students enrolled in their final year of high school (year 12) in participating schools will be invited to participate. To account for possible attrition, the target sample size was set at 1600 participants across 30 schools. Participating schools will be cluster randomised at the school level to receive either SPARX-R or lifeSTYLE, an attention-controlled placebo comparator. The control intervention is an online program aimed at maintaining a healthy lifestyle. The primary outcome will be symptoms of depression, and secondary outcomes will include symptoms of anxiety, suicidal ideation and behaviours, stigma and academic performance. Additional measures of cost-effectiveness, as well as process variables (e.g., adherence, acceptability) and potential predictors of response to treatment, will be collected. Consenting parents will be invited to complete measures regarding their own mental health and expectations for their child. Assessments will be conducted pre- and post-intervention and at 6- and 18-month follow-up. Primary analyses will compare changes in levels of depressive symptomatology for the intervention group relative to the attention control condition using mixed-effects model repeated-measures analyses to account for clustering within schools. This is the first trial of a universal depression prevention intervention delivered to school students in advance of a specific, significant stressor. If found to be effective, this program may offer schools a new approach to preparing students for their final year of schooling. Australian New Zealand Clinical Trials Registry identifier: ACTRN12614000316606 . Registered 25 March 2014.

The OGCleaner: filtering false-positive homology clusters.

PubMed

Fujimoto, M Stanley; Suvorov, Anton; Jensen, Nicholas O; Clement, Mark J; Snell, Quinn; Bybee, Seth M

2017-01-01

Detecting homologous sequences in organisms is an essential step in protein structure and function prediction, gene annotation and phylogenetic tree construction. Heuristic methods are often employed for quality control of putative homology clusters. These heuristics, however, usually only apply to pairwise sequence comparison and do not examine clusters as a whole. We present the Orthology Group Cleaner (the OGCleaner), a tool designed for filtering putative orthology groups as homology or non-homology clusters by considering all sequences in a cluster. The OGCleaner relies on high-quality orthologous groups identified in OrthoDB to train machine learning algorithms that are able to distinguish between true-positive and false-positive homology groups. This package aims to improve the quality of phylogenetic tree construction especially in instances of lower-quality transcriptome assemblies. https://github.com/byucsl/ogcleaner CONTACT: sfujimoto@gmail.comSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Self-consistent physical parameters for five intermediate-age SMC stellar clusters from CMD modelling

NASA Astrophysics Data System (ADS)

Dias, B.; Kerber, L. O.; Barbuy, B.; Santiago, B.; Ortolani, S.; Balbinot, E.

2014-01-01

Context. Stellar clusters in the Small Magellanic Cloud (SMC) are useful probes for studying the chemical and dynamical evolution of this neighbouring dwarf galaxy, enabling inspection of a large period covering over 10 Gyr. Aims: The main goals of this work are the derivation of age, metallicity, distance modulus, reddening, core radius, and central density profiles for six sample clusters, in order to place them in the context of the Small Cloud evolution. The studied clusters are AM 3, HW 1, HW 34, HW 40, Lindsay 2, and Lindsay 3; HW 1, HW 34, and Lindsay 2 are studied for the first time. Methods: Optical colour-magnitude diagrams (V,B - V CMDs) and radial density profiles were built from images obtained with the 4.1 m Southern Astrophysical Research (SOAR) telescope, reaching V ~ 23. The determination of structural parameters were carried out by applying King profile fitting. The other parameters were derived in a self-consistent way by means of isochrone fitting, which uses likelihood statistics to identify the synthetic CMDs that best reproduce the observed ones. Membership probabilities were determined comparing the cluster and control field CMDs. Completeness and photometric uncertainties were obtained by performing artificial star tests. Results: The results confirm that these clusters (except HW 34, identified as a field fluctuation) are intermediate-age clusters, with ages between 1.2 Gyr (Lindsay 3) and ~5.0 Gyr (HW 1). In particular HW 1, Lindsay 2 and Lindsay 3 are located in a region that we called West Halo, where studies of ages and metallicity gradients are still lacking. Moreover, Lindsay 2 was identified as a moderately metal-poor cluster with [Fe/H] = -1.4 ± 0.2 dex, lower than expected from the age-metallicity relation by Pagel & Tautvaisiene (1998). We also found distances varying from ~53 kpc to 66 kpc, compatible with the large depth of the SMC. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).Appendix A is available in electronic form at http://www.aanda.orgThe tables of photometry are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A106

HUBBLE VIEWS DISTANT GALAXIES THROUGH A COSMIC LENS

NASA Technical Reports Server (NTRS)

2002-01-01

This NASA Hubble Space Telescope image of the rich galaxy cluster, Abell 2218, is a spectacular example of gravitational lensing. The arc-like pattern spread across the picture like a spider web is an illusion caused by the gravitational field of the cluster. The cluster is so massive and compact that light rays passing through it are deflected by its enormous gravitational field, much as an optical lens bends light to form an image. The process magnifies, brightens and distorts images of objects that lie far beyond the cluster. This provides a powerful 'zoom lens' for viewing galaxies that are so far away they could not normally be observed with the largest available telescopes. Hubble's high resolution reveals numerous arcs which are difficult to detect with ground-based telescopes because they appear to be so thin. The arcs are the distorted images of a very distant galaxy population extending 5-10 times farther than the lensing cluster. This population existed when the universe was just one quarter of its present age. The arcs provide a direct glimpse of how star forming regions are distributed in remote galaxies, and other clues to the early evoution of galaxies. Hubble also reveals multiple imaging, a rarer lensing event that happens when the distortion is large enough to produce more than one image of the same galaxy. Abell 2218 has an unprecedented total of seven multiple systems. The abundance of lensing features in Abell 2218 has been used to make a detailed map of the distribution of matter in the cluster's center. From this, distances can be calculated for a sample of 120 faint arclets found on the Hubble image. These arclets represent galaxies that are 50 times fainter than objects that can be seen with ground-based telescopes. Studies of remote galaxies viewed through well-studied lenses like Abell 2218 promise to reveal the nature of normal galaxies at much earlier epochs than was previously possible. The technique is a powerful combination of Hubble's superlative capabilities and the 'natural' focusing properties of massive clusters like Abell 2218. The image was taken with the Wide Field Planetary Camera 2. Credits: W.Couch (University of New South Wales), R. Ellis (Cambridge University), and NASA

Automated segmentation of white matter fiber bundles using diffusion tensor imaging data and a new density based clustering algorithm.

PubMed

Kamali, Tahereh; Stashuk, Daniel

2016-10-01

Robust and accurate segmentation of brain white matter (WM) fiber bundles assists in diagnosing and assessing progression or remission of neuropsychiatric diseases such as schizophrenia, autism and depression. Supervised segmentation methods are infeasible in most applications since generating gold standards is too costly. Hence, there is a growing interest in designing unsupervised methods. However, most conventional unsupervised methods require the number of clusters be known in advance which is not possible in most applications. The purpose of this study is to design an unsupervised segmentation algorithm for brain white matter fiber bundles which can automatically segment fiber bundles using intrinsic diffusion tensor imaging data information without considering any prior information or assumption about data distributions. Here, a new density based clustering algorithm called neighborhood distance entropy consistency (NDEC), is proposed which discovers natural clusters within data by simultaneously utilizing both local and global density information. The performance of NDEC is compared with other state of the art clustering algorithms including chameleon, spectral clustering, DBSCAN and k-means using Johns Hopkins University publicly available diffusion tensor imaging data. The performance of NDEC and other employed clustering algorithms were evaluated using dice ratio as an external evaluation criteria and density based clustering validation (DBCV) index as an internal evaluation metric. Across all employed clustering algorithms, NDEC obtained the highest average dice ratio (0.94) and DBCV value (0.71). NDEC can find clusters with arbitrary shapes and densities and consequently can be used for WM fiber bundle segmentation where there is no distinct boundary between various bundles. NDEC may also be used as an effective tool in other pattern recognition and medical diagnostic systems in which discovering natural clusters within data is a necessity. Copyright © 2016 Elsevier B.V. All rights reserved.

EVIDENCE FOR THE UNIVERSALITY OF PROPERTIES OF RED-SEQUENCE GALAXIES IN X-RAY- AND RED-SEQUENCE-SELECTED CLUSTERS AT z ∼ 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foltz, R.; Wilson, G.; DeGroot, A.

We study the slope, intercept, and scatter of the color–magnitude and color–mass relations for a sample of 10 infrared red-sequence-selected clusters at z ∼ 1. The quiescent galaxies in these clusters formed the bulk of their stars above z ≳ 3 with an age spread Δt ≳ 1 Gyr. We compare UVJ color–color and spectroscopic-based galaxy selection techniques, and find a 15% difference in the galaxy populations classified as quiescent by these methods. We compare the color–magnitude relations from our red-sequence selected sample with X-ray- and photometric-redshift-selected cluster samples of similar mass and redshift. Within uncertainties, we are unable tomore » detect any difference in the ages and star formation histories of quiescent cluster members in clusters selected by different methods, suggesting that the dominant quenching mechanism is insensitive to cluster baryon partitioning at z ∼ 1.« less

Structure and Dynamics Ionic Block co-Polymer Melts: Computational Study

NASA Astrophysics Data System (ADS)

Aryal, Dipak; Perahia, Dvora; Grest, Gary S.

Tethering ionomer blocks into co-polymers enables engineering of polymeric systems designed to encompass transport while controlling structure. Here the structure and dynamics of symmetric pentablock copolymers melts are probed by fully atomistic molecular dynamics simulations. The center block consists of randomly sulfonated polystyrene with sulfonation fractions f = 0 to 0.55 tethered to a hydrogenated polyisoprene (PI), end caped with poly(t-butyl styrene). We find that melts with f = 0.15 and 0.30 consist of isolated ionic clusters whereas melts with f = 0.55 exhibit a long-range percolating ionic network. Similar to polystyrene sulfonate, a small number of ionic clusters slow the mobility of the center of mass of the co-polymer, however, formation of the ionic clusters is slower and they are often intertwined with PI segments. Surprisingly, the segmental dynamics of the other blocks are also affected. NSF DMR-1611136; NERSC; Palmetto Cluster Clemson University; Kraton Polymers US, LLC.

The VIMOS Public Extragalactic Redshift Survey (VIPERS) . Galaxy clustering and redshift-space distortions at z ≃ 0.8 in the first data release

NASA Astrophysics Data System (ADS)

de la Torre, S.; Guzzo, L.; Peacock, J. A.; Branchini, E.; Iovino, A.; Granett, B. R.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Moscardini, L.; Paioro, L.; Percival, W. J.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Monaco, P.; Nichol, R. C.; Phleps, S.; Wolk, M.; Zamorani, G.

2013-09-01

We present the general real- and redshift-space clustering properties of galaxies as measured in the first data release of the VIPERS survey. VIPERS is a large redshift survey designed to probe in detail the distant Universe and its large-scale structure at 0.5 < z < 1.2. We describe in this analysis the global properties of the sample and discuss the survey completeness and associated corrections. This sample allows us to measure the galaxy clustering with an unprecedented accuracy at these redshifts. From the redshift-space distortions observed in the galaxy clustering pattern we provide a first measurement of the growth rate of structure at z = 0.8: fσ8 = 0.47 ± 0.08. This is completely consistent with the predictions of standard cosmological models based on Einstein gravity, although this measurement alone does not discriminate between different gravity models. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

The linkage between ribosomal crystallography, metal ions, heteropolytungstates and functional flexibility

PubMed Central

Bashan, Anat; Yonath, Ada

2009-01-01

Crystallography of ribosomes, the universal cell nucleoprotein assemblies facilitating the translation of the genetic-code into proteins, met with severe problems owing to their large size, complex structure, inherent flexibility and high conformational variability. For the case of the small ribosomal subunit, which caused extreme difficulties, post crystallization treatment by minute amounts of a heteropolytungstate cluster allowed structure determination at atomic resolution. This cluster played a dual role in ribosomal crystallography: providing anomalous phasing power and dramatically increased the resolution, by stabilization of a selected functional conformation. Thus, four out of the fourteen clusters that bind to each of the crystallized small subunits are attached to a specific ribosomal protein in a fashion that may control a significant component of the subunit internal flexibility, by “gluing” symmetrical related subunits. Here we highlight basic issues in the relationship between metal ions and macromolecules and present common traits controlling in the interactions between polymetalates and various macromolecules, which may be extended towards the exploitation of polymetalates for therapeutical treatment. PMID:19915655

Dark Energy Found Stifling Growth in Universe

NASA Astrophysics Data System (ADS)

2008-12-01

WASHINGTON -- For the first time, astronomers have clearly seen the effects of "dark energy" on the most massive collapsed objects in the universe using NASA's Chandra X-ray Observatory. By tracking how dark energy has stifled the growth of galaxy clusters and combining this with previous studies, scientists have obtained the best clues yet about what dark energy is and what the destiny of the universe could be. This work, which took years to complete, is separate from other methods of dark energy research such as supernovas. These new X-ray results provide a crucial independent test of dark energy, long sought by scientists, which depends on how gravity competes with accelerated expansion in the growth of cosmic structures. Techniques based on distance measurements, such as supernova work, do not have this special sensitivity. Scientists think dark energy is a form of repulsive gravity that now dominates the universe, although they have no clear picture of what it actually is. Understanding the nature of dark energy is one of the biggest problems in science. Possibilities include the cosmological constant, which is equivalent to the energy of empty space. Other possibilities include a modification in general relativity on the largest scales, or a more general physical field. People Who Read This Also Read... Chandra Data Reveal Rapidly Whirling Black Holes Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters Powerful Nearby Supernova Caught By Web Cassiopeia A Comes Alive Across Time and Space To help decide between these options, a new way of looking at dark energy is required. It is accomplished by observing how cosmic acceleration affects the growth of galaxy clusters over time. "This result could be described as 'arrested development of the universe'," said Alexey Vikhlinin of the Smithsonian Astrophysical Observatory in Cambridge, Mass., who led the research. "Whatever is forcing the expansion of the universe to speed up is also forcing its development to slow down." Vikhlinin and his colleagues used Chandra to observe the hot gas in dozens of galaxy clusters, which are the largest collapsed objects in the universe. Some of these clusters are relatively close and others are more than halfway across the universe. The results show the increase in mass of the galaxy clusters over time aligns with a universe dominated by dark energy. It is more difficult for objects like galaxy clusters to grow when space is stretched, as caused by dark energy. Vikhlinin and his team see this effect clearly in their data. The results are remarkably consistent with those from the distance measurements, revealing general relativity applies, as expected, on large scales. "For years, scientists have wanted to start testing how gravity works on large scales and now, we finally have," said William Forman, a co-author of the study from the Smithsonian Astrophysical Observatory. "This is a test that general relativity could have failed." When combined with other clues -- supernovas, the study of the cosmic microwave background, and the distribution of galaxies -- this new X-ray result gives scientists the best insight to date on the properties of dark energy. The study strengthens the evidence that dark energy is the cosmological constant. Although it is the leading candidate to explain dark energy, theoretical work suggests it should be about 10 raised to the power of 120 times larger than observed. Therefore, alternatives to general relativity, such as theories involving hidden dimensions, are being explored. "Putting all of this data together gives us the strongest evidence yet that dark energy is the cosmological constant, or in other words, that 'nothing weighs something'," said Vikhlinin. "A lot more testing is needed, but so far Einstein's theory is looking as good as ever." These results have consequences for predicting the ultimate fate of the universe. If dark energy is explained by the cosmological constant, the expansion of the universe will continue to accelerate, and the Milky Way and its neighbor galaxy, Andromeda, never will merge with the Virgo cluster. In that case, about a hundred billion years from now, all other galaxies ultimately would disappear from the Milky Way's view and, eventually, the local superclusters of galaxies also would disintegrate. The work by Vikhlinin and his colleagues will be published in two separate papers in the Feb. 10 issue of The Astrophysical Journal. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Shape characteristics of equilibrium and non-equilibrium fractal clusters.

PubMed

Mansfield, Marc L; Douglas, Jack F

2013-07-28

It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other between the viscosity and hydrodynamic radii, as potential measures of shape anisotropy. We also find a strong correlation between anisotropy and effective fractal dimension. These observations should provide new practical methods for quantifying the nature of particle clustering in diverse contexts.

The Flies and Eyes project: design and methods of a cluster-randomised intervention study to confirm the importance of flies as trachoma vectors in The Gambia and to test a sustainable method of fly control using pit latrines.

PubMed

Emerson, Paul M; Lindsay, Steve W; Walraven, Gijs E L; Dibba, Sheikh Mafuji; Lowe, Kebba O; Bailey, Robin L

2002-04-01

The Flies and Eyes project is a community-based, cluster-randomised, intervention trial based in a rural area of The Gambia. It was designed to prove whether flies are mechanical vectors of trachoma; to quantify the relative importance of flies as vectors of trachoma and to test the effectiveness of insecticide spraying and the provision of latrines in trachoma control. A total of 21 clusters, each composed of 300-550 people, are to be recruited in groups of three. One cluster from each group is randomly allocated to receive insecticide spraying, one to receive pit latrines and the remaining to act as a control. The seven groups of clusters are recruited on a step-wise basis separated by two months to aid logistics and allow all seasons to be covered. Standardised, validated trachoma surveys are conducted for people of all ages and both sexes at baseline and six months post intervention. The Muscid fly population is monitored using standard traps and fly-eye contact is measured with catches of flies direct from children's faces. The Flies and Eyes project has been designed to strengthen the evidence base for the 'E' component of the SAFE strategy for trachoma control. The results will assist programme planners and country co-ordinators to make informed decisions on the environmental aspects of trachoma control.

Web-based consultation between general practitioners and nephrologists: a cluster randomized controlled trial.

PubMed

van Gelder, Vincent A; Scherpbier-de Haan, Nynke D; van Berkel, Saskia; Akkermans, Reinier P; de Grauw, Inge S; Adang, Eddy M; Assendelft, Pim J; de Grauw, Wim J C; Biermans, Marion C J; Wetzels, Jack F M

2017-08-01

Consultation of a nephrologist is important in aligning care for patients with chronic kidney disease (CKD) at the primary-secondary care interface. However, current consultation methods come with practical difficulties that can lead to postponed consultation or patient referral instead. This study aimed to investigate whether a web-based consultation platform, telenephrology, led to a lower referral rate of indicated patients. Furthermore, we assessed consultation rate, quality of care, costs and general practitioner (GPs') experiences with telenephrology. Cluster randomized controlled trial with 47 general practices in the Netherlands was randomized to access to telenephrology or to enhanced usual care. A total of 3004 CKD patients aged 18 years or older who were under primary care were included (intervention group n = 1277, control group n = 1727) and 2693 completed the trial. All practices participated in a CKD management course and were given an overview of their CKD patients. The referral rates amounted to 2.3% (n = 29) in the intervention group and 3.0% (n = 52) in the control group, which was a non-significant difference, OR 0.61; 95% CI 0.31 to 1.23. The intervention group's consultation rate was 6.3% (n = 81) against 5.0% (n = 87) (OR 2.00; 95% CI 0.75-5.33). We found no difference in quality of care or costs. The majority of GPs had a positive opinion about telenephrology. The data in our study do not allow for conclusions on the effect of telenephrology on the rate of patient referrals and provider-to-provider consultations, compared to conventional methods. It was positively evaluated by GPs and was non-inferior in terms of quality of care and costs. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

JMS: An Open Source Workflow Management System and Web-Based Cluster Front-End for High Performance Computing.

PubMed

Brown, David K; Penkler, David L; Musyoka, Thommas M; Bishop, Özlem Tastan

2015-01-01

Complex computational pipelines are becoming a staple of modern scientific research. Often these pipelines are resource intensive and require days of computing time. In such cases, it makes sense to run them over high performance computing (HPC) clusters where they can take advantage of the aggregated resources of many powerful computers. In addition to this, researchers often want to integrate their workflows into their own web servers. In these cases, software is needed to manage the submission of jobs from the web interface to the cluster and then return the results once the job has finished executing. We have developed the Job Management System (JMS), a workflow management system and web interface for high performance computing (HPC). JMS provides users with a user-friendly web interface for creating complex workflows with multiple stages. It integrates this workflow functionality with the resource manager, a tool that is used to control and manage batch jobs on HPC clusters. As such, JMS combines workflow management functionality with cluster administration functionality. In addition, JMS provides developer tools including a code editor and the ability to version tools and scripts. JMS can be used by researchers from any field to build and run complex computational pipelines and provides functionality to include these pipelines in external interfaces. JMS is currently being used to house a number of bioinformatics pipelines at the Research Unit in Bioinformatics (RUBi) at Rhodes University. JMS is an open-source project and is freely available at https://github.com/RUBi-ZA/JMS.

JMS: An Open Source Workflow Management System and Web-Based Cluster Front-End for High Performance Computing

PubMed Central

Brown, David K.; Penkler, David L.; Musyoka, Thommas M.; Bishop, Özlem Tastan

2015-01-01

Complex computational pipelines are becoming a staple of modern scientific research. Often these pipelines are resource intensive and require days of computing time. In such cases, it makes sense to run them over high performance computing (HPC) clusters where they can take advantage of the aggregated resources of many powerful computers. In addition to this, researchers often want to integrate their workflows into their own web servers. In these cases, software is needed to manage the submission of jobs from the web interface to the cluster and then return the results once the job has finished executing. We have developed the Job Management System (JMS), a workflow management system and web interface for high performance computing (HPC). JMS provides users with a user-friendly web interface for creating complex workflows with multiple stages. It integrates this workflow functionality with the resource manager, a tool that is used to control and manage batch jobs on HPC clusters. As such, JMS combines workflow management functionality with cluster administration functionality. In addition, JMS provides developer tools including a code editor and the ability to version tools and scripts. JMS can be used by researchers from any field to build and run complex computational pipelines and provides functionality to include these pipelines in external interfaces. JMS is currently being used to house a number of bioinformatics pipelines at the Research Unit in Bioinformatics (RUBi) at Rhodes University. JMS is an open-source project and is freely available at https://github.com/RUBi-ZA/JMS. PMID:26280450

Markov Chain Model-Based Optimal Cluster Heads Selection for Wireless Sensor Networks

PubMed Central

Ahmed, Gulnaz; Zou, Jianhua; Zhao, Xi; Sadiq Fareed, Mian Muhammad

2017-01-01

The longer network lifetime of Wireless Sensor Networks (WSNs) is a goal which is directly related to energy consumption. This energy consumption issue becomes more challenging when the energy load is not properly distributed in the sensing area. The hierarchal clustering architecture is the best choice for these kind of issues. In this paper, we introduce a novel clustering protocol called Markov chain model-based optimal cluster heads (MOCHs) selection for WSNs. In our proposed model, we introduce a simple strategy for the optimal number of cluster heads selection to overcome the problem of uneven energy distribution in the network. The attractiveness of our model is that the BS controls the number of cluster heads while the cluster heads control the cluster members in each cluster in such a restricted manner that a uniform and even load is ensured in each cluster. We perform an extensive range of simulation using five quality measures, namely: the lifetime of the network, stable and unstable region in the lifetime of the network, throughput of the network, the number of cluster heads in the network, and the transmission time of the network to analyze the proposed model. We compare MOCHs against Sleep-awake Energy Efficient Distributed (SEED) clustering, Artificial Bee Colony (ABC), Zone Based Routing (ZBR), and Centralized Energy Efficient Clustering (CEEC) using the above-discussed quality metrics and found that the lifetime of the proposed model is almost 1095, 2630, 3599, and 2045 rounds (time steps) greater than SEED, ABC, ZBR, and CEEC, respectively. The obtained results demonstrate that the MOCHs is better than SEED, ABC, ZBR, and CEEC in terms of energy efficiency and the network throughput. PMID:28241492

The Gaia-ESO Survey: Probes of the inner disk abundance gradient

NASA Astrophysics Data System (ADS)

Jacobson, H. R.; Friel, E. D.; Jílková, L.; Magrini, L.; Bragaglia, A.; Vallenari, A.; Tosi, M.; Randich, S.; Donati, P.; Cantat-Gaudin, T.; Sordo, R.; Smiljanic, R.; Overbeek, J. C.; Carraro, G.; Tautvaišienė, G.; San Roman, I.; Villanova, S.; Geisler, D.; Muñoz, C.; Jiménez-Esteban, F.; Tang, B.; Gilmore, G.; Alfaro, E. J.; Bensby, T.; Flaccomio, E.; Koposov, S. E.; Korn, A. J.; Pancino, E.; Recio-Blanco, A.; Casey, A. R.; Costado, M. T.; Franciosini, E.; Heiter, U.; Hill, V.; Hourihane, A.; Lardo, C.; de Laverny, P.; Lewis, J.; Monaco, L.; Morbidelli, L.; Sacco, G. G.; Sousa, S. G.; Worley, C. C.; Zaggia, S.

2016-06-01

Context. The nature of the metallicity gradient inside the solar circle (RGC < 8 kpc) is poorly understood, but studies of Cepheids and a small sample of open clusters suggest that it steepens in the inner disk. Aims: We investigate the metallicity gradient of the inner disk using a sample of inner disk open clusters that is three times larger than has previously been studied in the literature to better characterize the gradient in this part of the disk. Methods: We used the Gaia-ESO Survey (GES) [Fe/H] values and stellar parameters for stars in 12 open clusters in the inner disk from GES-UVES data. Cluster mean [Fe/H] values were determined based on a membership analysis for each cluster. Where necessary, distances and ages to clusters were determined via comparison to theoretical isochrones. Results: The GES open clusters exhibit a radial metallicity gradient of -0.10 ± 0.02 dex kpc-1, consistent with the gradient measured by other literature studies of field red giant stars and open clusters in the range RGC ~ 6-12 kpc. We also measure a trend of increasing [Fe/H] with increasing cluster age, as has also been found in the literature. Conclusions: We find no evidence for a steepening of the inner disk metallicity gradient inside the solar circle as earlier studies indicated. The age-metallicity relation shown by the clusters is consistent with that predicted by chemical evolution models that include the effects of radial migration, but a more detailed comparison between cluster observations and models would be premature. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002 and 193.B-0936. These data products have been processed by the Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia-ESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council.Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A37

A school-based intervention incorporating smartphone technology to improve health-related fitness among adolescents: rationale and study protocol for the NEAT and ATLAS 2.0 cluster randomised controlled trial and dissemination study

PubMed Central

Lubans, David R; Smith, Jordan J; Peralta, Louisa R; Plotnikoff, Ronald C; Okely, Anthony D; Salmon, Jo; Eather, Narelle; Dewar, Deborah L; Kennedy, Sarah; Lonsdale, Chris; Hilland, Toni A; Estabrooks, Paul; Finn, Tara L; Pollock, Emma; Morgan, Philip J

2016-01-01

Introduction Physical inactivity has been described as a global pandemic. Interventions aimed at developing skills in lifelong physical activities may provide the foundation for an active lifestyle into adulthood. In general, school-based physical activity interventions targeting adolescents have produced modest results and few have been designed to be ‘scaled-up’ and disseminated. This study aims to: (1) assess the effectiveness of two physical activity promotion programmes (ie, NEAT and ATLAS) that have been modified for scalability; and (2) evaluate the dissemination of these programmes throughout government funded secondary schools. Methods and analysis The study will be conducted in two phases. In the first phase (cluster randomised controlled trial), 16 schools will be randomly allocated to the intervention or a usual care control condition. In the second phase, the Reach, Effectiveness, Adoption, Implementation and Maintenance (Re-AIM) framework will be used to guide the design and evaluation of programme dissemination throughout New South Wales (NSW), Australia. In both phases, teachers will be trained to deliver the NEAT and ATLAS programmes, which will include: (1) interactive student seminars; (2) structured physical activity programmes; (3) lunch-time fitness sessions; and (4) web-based smartphone apps. In the cluster RCT, study outcomes will be assessed at baseline, 6 months (primary end point) and 12-months. Muscular fitness will be the primary outcome and secondary outcomes will include: objectively measured body composition, cardiorespiratory fitness, flexibility, resistance training skill competency, physical activity, self-reported recreational screen-time, sleep, sugar-sweetened beverage and junk food snack consumption, self-esteem and well-being. Ethics and dissemination This study has received approval from the University of Newcastle (H-2014-0312) and the NSW Department of Education (SERAP: 2012121) human research ethics committees. This study is funded by the Australian Research Council (FT140100399) and the NSW Department of Education. Trial registration number ACTRN12615000360516; Pre-results. PMID:27354070

A school-based intervention incorporating smartphone technology to improve health-related fitness among adolescents: rationale and study protocol for the NEAT and ATLAS 2.0 cluster randomised controlled trial and dissemination study.

PubMed

Lubans, David R; Smith, Jordan J; Peralta, Louisa R; Plotnikoff, Ronald C; Okely, Anthony D; Salmon, Jo; Eather, Narelle; Dewar, Deborah L; Kennedy, Sarah; Lonsdale, Chris; Hilland, Toni A; Estabrooks, Paul; Finn, Tara L; Pollock, Emma; Morgan, Philip J

2016-06-27

Physical inactivity has been described as a global pandemic. Interventions aimed at developing skills in lifelong physical activities may provide the foundation for an active lifestyle into adulthood. In general, school-based physical activity interventions targeting adolescents have produced modest results and few have been designed to be 'scaled-up' and disseminated. This study aims to: (1) assess the effectiveness of two physical activity promotion programmes (ie, NEAT and ATLAS) that have been modified for scalability; and (2) evaluate the dissemination of these programmes throughout government funded secondary schools. The study will be conducted in two phases. In the first phase (cluster randomised controlled trial), 16 schools will be randomly allocated to the intervention or a usual care control condition. In the second phase, the Reach, Effectiveness, Adoption, Implementation and Maintenance (Re-AIM) framework will be used to guide the design and evaluation of programme dissemination throughout New South Wales (NSW), Australia. In both phases, teachers will be trained to deliver the NEAT and ATLAS programmes, which will include: (1) interactive student seminars; (2) structured physical activity programmes; (3) lunch-time fitness sessions; and (4) web-based smartphone apps. In the cluster RCT, study outcomes will be assessed at baseline, 6 months (primary end point) and 12-months. Muscular fitness will be the primary outcome and secondary outcomes will include: objectively measured body composition, cardiorespiratory fitness, flexibility, resistance training skill competency, physical activity, self-reported recreational screen-time, sleep, sugar-sweetened beverage and junk food snack consumption, self-esteem and well-being. This study has received approval from the University of Newcastle (H-2014-0312) and the NSW Department of Education (SERAP: 2012121) human research ethics committees. This study is funded by the Australian Research Council (FT140100399) and the NSW Department of Education. ACTRN12615000360516; Pre-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Reconciling research and implementation in micro health insurance experiments in India: study protocol for a randomized controlled trial

PubMed Central

2011-01-01

Background Microinsurance or Community-Based Health Insurance is a promising healthcare financing mechanism, which is increasingly applied to aid rural poor persons in low-income countries. Robust empirical evidence on the causal relations between Community-Based Health Insurance and healthcare utilisation, financial protection and other areas is scarce and necessary. This paper contains a discussion of the research design of three Cluster Randomised Controlled Trials in India to measure the impact of Community-Based Health Insurance on several outcomes. Methods/Design Each trial sets up a Community-Based Health Insurance scheme among a group of micro-finance affiliate families. Villages are grouped into clusters which are congruous with pre-existing social groupings. These clusters are randomly assigned to one of three waves of implementation, ensuring the entire population is offered Community-Based Health Insurance by the end of the experiment. Each wave of treatment is preceded by a round of mixed methods evaluation, with quantitative, qualitative and spatial evidence on impact collected. Improving upon practices in published Cluster Randomised Controlled Trial literature, we detail how research design decisions have ensured that both the households offered insurance and the implementers of the Community-Based Health Insurance scheme operate in an environment replicating a non-experimental implementation. Discussion When a Cluster Randomised Controlled Trial involves randomizing within a community, generating adequate and valid conclusions requires that the research design must be made congruous with social structures within the target population, to ensure that such trials are conducted in an implementing environment which is a suitable analogue to that of a non-experimental implementing environment. PMID:21988774

Reconciling research and implementation in micro health insurance experiments in India: study protocol for a randomized controlled trial.

PubMed

Doyle, Conor; Panda, Pradeep; Van de Poel, Ellen; Radermacher, Ralf; Dror, David M

2011-10-11

Microinsurance or Community-Based Health Insurance is a promising healthcare financing mechanism, which is increasingly applied to aid rural poor persons in low-income countries. Robust empirical evidence on the causal relations between Community-Based Health Insurance and healthcare utilisation, financial protection and other areas is scarce and necessary. This paper contains a discussion of the research design of three Cluster Randomised Controlled Trials in India to measure the impact of Community-Based Health Insurance on several outcomes. Each trial sets up a Community-Based Health Insurance scheme among a group of micro-finance affiliate families. Villages are grouped into clusters which are congruous with pre-existing social groupings. These clusters are randomly assigned to one of three waves of implementation, ensuring the entire population is offered Community-Based Health Insurance by the end of the experiment. Each wave of treatment is preceded by a round of mixed methods evaluation, with quantitative, qualitative and spatial evidence on impact collected. Improving upon practices in published Cluster Randomised Controlled Trial literature, we detail how research design decisions have ensured that both the households offered insurance and the implementers of the Community-Based Health Insurance scheme operate in an environment replicating a non-experimental implementation. When a Cluster Randomised Controlled Trial involves randomizing within a community, generating adequate and valid conclusions requires that the research design must be made congruous with social structures within the target population, to ensure that such trials are conducted in an implementing environment which is a suitable analogue to that of a non-experimental implementing environment. © 2011 Doyle et al; licensee BioMed Central Ltd.

Effectiveness and feasibility of long-lasting insecticide-treated curtains and water container covers for dengue vector control in Colombia: a cluster randomised trial.

PubMed

Quintero, Juliana; García-Betancourt, Tatiana; Cortés, Sebastian; García, Diana; Alcalá, Lucas; González-Uribe, Catalina; Brochero, Helena; Carrasquilla, Gabriel

2015-02-01

Long-lasting insecticide-treated net (LLIN) window and door curtains alone or in combination with LLIN water container covers were analysed regarding effectiveness in reducing dengue vector density, and feasibility of the intervention. A cluster randomised trial was conducted in an urban area of Colombia comparing 10 randomly selected control and 10 intervention clusters. In control clusters, routine vector control activities were performed. The intervention delivered first, LLIN curtains (from July to August 2013) and secondly, water container covers (from October to March 2014). Cross-sectional entomological surveys were carried out at baseline (February 2013 to June 2013), 9 weeks after the first intervention (August to October 2013), and 4-6 weeks after the second intervention (March to April 2014). Curtains were installed in 922 households and water container covers in 303 households. The Breteau index (BI) fell from 14 to 6 in the intervention group and from 8 to 5 in the control group. The additional intervention with LLIN covers for water containers showed a significant reduction in pupae per person index (PPI) (p=0.01). In the intervention group, the PPI index showed a clear decline of 71% compared with 25% in the control group. Costs were high but options for cost savings were identified. Short term impact evaluation indicates that the intervention package can reduce dengue vector density but sustained effect will depend on multiple factors. © The author 2015. The World Health Organization has granted Oxford University Press permission for the reproduction of this article.

Final Report for "Non-Accelerator Physics – Research in High Energy Physics: Dark Energy Research on DES"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ritz, Steve; Jeltema, Tesla

One of the greatest mysteries in modern cosmology is the fact that the expansion of the universe is observed to be accelerating. This acceleration may stem from dark energy, an additional energy component of the universe, or may indicate that the theory of general relativity is incomplete on cosmological scales. The growth rate of large-scale structure in the universe and particularly the largest collapsed structures, clusters of galaxies, is highly sensitive to the underlying cosmology. Clusters will provide one of the single most precise methods of constraining dark energy with the ongoing Dark Energy Survey (DES). The accuracy of themore » cosmological constraints derived from DES clusters necessarily depends on having an optimized and well-calibrated algorithm for selecting clusters as well as an optical richness estimator whose mean relation and scatter compared to cluster mass are precisely known. Calibrating the galaxy cluster richness-mass relation and its scatter was the focus of the funded work. Specifically, we employ X-ray observations and optical spectroscopy with the Keck telescopes of optically-selected clusters to calibrate the relationship between optical richness (the number of galaxies in a cluster) and underlying mass. This work also probes aspects of cluster selection like the accuracy of cluster centering which are critical to weak lensing cluster studies.« less

Structure and Formation of cD Galaxies: NGC 6166 in ABELL 2199

NASA Astrophysics Data System (ADS)

Bender, Ralf; Kormendy, John; Cornell, Mark E.; Fisher, David B.

2015-07-01

 Hobby-Eberly Telescope (HET) spectroscopy is used to measure the velocity dispersion profile of the nearest prototypical cD galaxy, NGC 6166 in the cluster Abell 2199. We also present composite surface photometry from many telescopes. We confirm the defining feature of a cD galaxy; i.e., (we suggest), a halo of stars that fills the cluster center and that is controlled dynamically by cluster gravity, not by the central galaxy. Our HET spectroscopy shows that the velocity dispersion of NGC 6166 rises from σ ≃ 300 km s-1 in the inner r˜ 10\\prime\\prime to σ =865+/- 58 km s-1 at r ˜ 100″ in the cD halo. This extends published observations of an outward σ increase and shows for the first time that σ rises all the way to the cluster velocity dispersion of 819 ± 32 km s-1. We also observe that the main body of NGC 6166 moves at +206 ± 39 km s-1 with respect to the cluster mean velocity, but the velocity of the inner cD halo is ˜70 km s-1 closer to the cluster velocity. These results support our picture that cD halos consist of stars that were stripped from individual cluster galaxies by fast tidal encounters.  However, our photometry does not confirm the widespread view that cD halos are identifiable as an extra, low-surface-brightness component that is photometrically distinct from the inner, steep-Sérsic-function main body of an otherwise-normal giant elliptical galaxy. Instead, all of the brightness profile of NGC 6166 outside its core is described to ±0.037 V mag arcsec-2 by a single Sérsic function with index n≃ 8.3. The cD halo is not recognizable from photometry alone. This blurs the distinction between cluster-dominated cD halos and the similarly-large-Sérsic-index halos of giant, core-boxy-nonrotating ellipticals. These halos are believed to be accreted onto compact, high-redshift progenitors (“red nuggets”) by large numbers of minor mergers. They belong dynamically to their central galaxies. Still, cDs and core-boxy-nonrotating Es may be more similar than we think: both may have outer halos made largely via minor mergers and the accumulation of tidal debris.  We construct a main-body+cD-halo decomposition that fits both the brightness and dispersion profiles. To fit σ (r), we need to force the component Sérsic indices to be smaller than a minimum-{χ }2 photometric decomposition would suggest. The main body has {M}V≃ -22.8≃ 30% of the total galaxy light. The cD halo has {M}V≃ -23.7, ˜1/2 mag brighter than the brightest galaxy in the Virgo cluster. A mass model based on published cluster dynamics and X-ray observations fits our observations if the tangential dispersion is larger than the radial dispersion at r≃ 20\\prime\\prime -60\\prime\\prime . The cD halo is as enhanced in α element abundances as the main body of NGC 6166. Quenching of star formation in ≲1 Gyr suggests that the center of Abell 2199 has been special for a long time during which dynamical evolution has liberated a large mass of now-intracluster stars. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Massive Stars and Star Clusters in the Era of JWST

NASA Astrophysics Data System (ADS)

Klein, Richard

Massive stars lie at the center of the web of physical processes that has shaped the universe as we know it, governing the evolution of the interstellar medium of galaxies, producing a majority of the heavy elements, and thereby determining the evolution of galaxies. Massive stars are also important as signposts, since they produce most of the light and almost all the ionizing radiation in regions of active star formation. A significant fraction of all stars form in massive clusters, which will be observable throughout the visible universe with JWST. Their luminosities are so high that the pressure of their light on interstellar dust grains is likely the dominant feedback mechanism regulating their formation. While this process has been studied in the local Universe, much less attention has been focused on how it behaves at high redshift, where the dust abundance is much lower due to the overall lower abundance of heavy elements. The high redshift Universe also differs from the nearby one in that observations imply that high redshift star formation occurs at significantly higher densities than are typically found locally. We propose to simulate the formation of individual massive stars from the high redshift universe to the present day universe spanning metallicities ranging from 0.001 to 1.0 and column densities from 0.1to 30.0 g/cm2 focusing on how the process depends on both the dust abundance and on the density of the star-forming gas. These simulations will be among the first to treat the formation of Population II stars, which form in regions of low metallicity. Based on these results, we shall then simulate the formation of clusters of stars across also cosmic time, both of moderate mass, such as the Orion Nebula Cluster, and of high mass, such as the super star clusters seen in starburst galaxies. These state-of-the-art simulations will be carried out using our newly developed advanced techniques in our radiation-magneto-hydrodynamic AMR code ORION, for radiative transfer with both ionizing and non-ionizing radiation that accurately handle both the direct radiation from stars and the diffuse infrared radiation field that builds up when direct radiation is reprocessed by dust grains. Our simulations include all of the relevant feedback effects such as radiative heating, radiation pressure, photodissociation and photoionization, protostellar outflows and stellar winds. The challenge in simulating the formation of massive stars and massive clusters is to include all these feedback effects self-consistently as they occur collectively. We are in an excellent position to do so. The results of these simulations will be directly relevant to the interpretation of observations with JWST, which will probe cluster formation in both the nearby and distant universe, and with SOFIA, which can observe high-mass star formation in the Galaxy. We shall make direct comparison with observations of massive protostars in the Galactic disk. We shall also compare with observations of star clusters that form in dense environments, such as the Galactic Center and in merging galaxies (e.g., the Antennae), and in low metallicity environments, such as the dwarf starburst galaxy I Zw 18. Once our simulations have been benchmarked with observations of massive protostars in the Galaxy and massive protoclusters in the local universe, they will provide the theoretical basis for interpreting observations of the formation of massive star clusters at high redshift with JWST. What determines the maximum mass of a star? How does stellar feedback affect the formation of individual stars and the formation of massive star clusters and how the answers to these questions evolve with cosmic time. The proposed research will provide high-resolution input to the study of stellar feedback on galaxy formation with a significantly more accurate treatment of the physics, particularly the radiative transfer that is so important for feedback.

Laser-directed hierarchical assembly of liquid crystal defects and control of optical phase singularities

PubMed Central

Ackerman, Paul J.; Qi, Zhiyuan; Lin, Yiheng; Twombly, Christopher W.; Laviada, Mauricio J.; Lansac, Yves; Smalyukh, Ivan I.

2012-01-01

Topological defect lines are ubiquitous and important in a wide variety of fascinating phenomena and theories in many fields ranging from materials science to early-universe cosmology, and to engineering of laser beams. However, they are typically hard to control in a reliable manner. Here we describe facile erasable “optical drawing” of self-assembled defect clusters in liquid crystals. These quadrupolar defect clusters, stabilized by the medium's chirality and the tendency to form twisted configurations, are shaped into arbitrary two-dimensional patterns, including reconfigurable phase gratings capable of generating and controlling optical phase singularities in laser beams. Our findings bridge the studies of defects in condensed matter physics and optics and may enable applications in data storage, singular optics, displays, electro-optic devices, diffraction gratings, as well as in both optically- and electrically-addressed pixel-free spatial light modulators. PMID:22679553

Laser-Directed Hierarchical Assembly of Liquid Crystal Defects and Control of Optical Phase Singularities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ackerman, P. J.; Qi, Z. Y.; Lin, Y. H.

2012-06-07

Topological defect lines are ubiquitous and important in a wide variety of fascinating phenomena and theories in many fields ranging from materials science to early-universe cosmology, and to engineering of laser beams. However, they are typically hard to control in a reliable manner. Here we describe facile erasable 'optical drawing' of self-assembled defect clusters in liquid crystals. These quadrupolar defect clusters, stabilized by the medium's chirality and the tendency to form twisted configurations, are shaped into arbitrary two-dimensional patterns, including reconfigurable phase gratings capable of generating and controlling optical phase singularities in laser beams. Our findings bridge the studies ofmore » defects in condensed matter physics and optics and may enable applications in data storage, singular optics, displays, electro-optic devices, diffraction gratings, as well as in both optically- and electrically-addressed pixel-free spatial light modulators.« less

The Ethical Behaviors of Educational Leaders in Ethiopian Public Universities: The Case of the Western Cluster Universities

ERIC Educational Resources Information Center

Amsale, Frew; Bekele, Mitiku; Tafesse, Mebratu

2016-01-01

The purpose of this study was to assess the extent to which educational leaders in the western cluster public universities of Ethiopia are ethical. Ethical leadership variables such as fairness, equity, multicultural competence, modeling ethical behaviors and altruism are considered in describing the ethical behaviors of the leaders. Descriptive…

A Massive Galaxy Cluster At z=1.45 From The XMM Cluster Survey: Discovery, Confirmation And Implications For The L-T Relation And Cosmology

NASA Astrophysics Data System (ADS)

Sabirli, Kivanc; Romer, A. K.; Davidson, M.; Stanford, S. A.; Viana, P. T.; Hilton, M.; Collins, C. A.; Kay, S. T.; Liddle, A. R.; Mann, R. G.; Miller, C. J.; Nichol, R. C.; West, M. J.; Conselice, C. J.; Spinrad, H.; Stern, D.; XCS Collaboration

2006-06-01

We report the discovery of the hottest cluster known at z > 1. It was identified as an extended X-ray source in the XMM Cluster Survey (XCS, Romer et al., 2001) and optical spectroscopy shows that 6 galaxies within a 60 arcsec diameter region lie at z = 1.45 ± 0.01. Hence its redshift is the highest currently known for a spectroscopically-confirmed cluster. Analysis of the X-ray spectra yields kT = 7.9+2.8-1.8 keV (90% confidence) and suggests that it is relatively massive for such a high redshift cluster.We acknowledge financial support from NASA grant NAG-11634 (AKR, RCN, KS, MD, PTPV), The Royal Astronomical Society's Hosie Request (MD, KS), PPARC (ARL, STK, RGM), the NASA XMM program (KS), the Institute of Astronomy at the University of Edinburgh (MD), Liverpool John Moores University (MH), Carnegie Mellon University (KS, AKR), and NSF grant AST-0205960 (MJW).

Long-term analysis of health status and preventive behavior in music students across an entire university program.

PubMed

Spahn, Claudia; Nusseck, Manfred; Zander, Mark

2014-03-01

The aim of this investigation was to analyze longitudinal data concerning physical and psychological health, playing-related problems, and preventive behavior among music students across their complete 4- to 5-year study period. In a longitudinal, observational study, we followed students during their university training and measured their psychological and physical health status and preventive behavior using standardized questionnaires at four different times. The data were in accordance with previous findings. They demonstrated three groups of health characteristics observed in beginners of music study: healthy students (cluster 1), students with preclinical symptoms (cluster 2), and students who are clinically symptomatic (cluster 3). In total, 64% of all students remained in the same cluster group during their whole university training. About 10% of the students showed considerable health problems and belonged to the third cluster group. The three clusters of health characteristics found in this longitudinal study with music students necessitate that prevention programs for musicians must be adapted to the target audience.

Clustering of galaxies with f(R) gravity

NASA Astrophysics Data System (ADS)

Capozziello, Salvatore; Faizal, Mir; Hameeda, Mir; Pourhassan, Behnam; Salzano, Vincenzo; Upadhyay, Sudhaker

2018-02-01

Based on thermodynamics, we discuss the galactic clustering of expanding Universe by assuming the gravitational interaction through the modified Newton's potential given by f(R) gravity. We compute the corrected N-particle partition function analytically. The corrected partition function leads to more exact equations of state of the system. By assuming that the system follows quasi-equilibrium, we derive the exact distribution function that exhibits the f(R) correction. Moreover, we evaluate the critical temperature and discuss the stability of the system. We observe the effects of correction of f(R) gravity on the power-law behaviour of particle-particle correlation function also. In order to check the feasibility of an f(R) gravity approach to the clustering of galaxies, we compare our results with an observational galaxy cluster catalogue.

Faster sequence homology searches by clustering subsequences.

PubMed

Suzuki, Shuji; Kakuta, Masanori; Ishida, Takashi; Akiyama, Yutaka

2015-04-15

Sequence homology searches are used in various fields. New sequencing technologies produce huge amounts of sequence data, which continuously increase the size of sequence databases. As a result, homology searches require large amounts of computational time, especially for metagenomic analysis. We developed a fast homology search method based on database subsequence clustering, and implemented it as GHOSTZ. This method clusters similar subsequences from a database to perform an efficient seed search and ungapped extension by reducing alignment candidates based on triangle inequality. The database subsequence clustering technique achieved an ∼2-fold increase in speed without a large decrease in search sensitivity. When we measured with metagenomic data, GHOSTZ is ∼2.2-2.8 times faster than RAPSearch and is ∼185-261 times faster than BLASTX. The source code is freely available for download at http://www.bi.cs.titech.ac.jp/ghostz/ akiyama@cs.titech.ac.jp Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press.

Aircraft ride quality controller design using new robust root clustering theory for linear uncertain systems

NASA Technical Reports Server (NTRS)

Yedavalli, R. K.

1992-01-01

The aspect of controller design for improving the ride quality of aircraft in terms of damping ratio and natural frequency specifications on the short period dynamics is addressed. The controller is designed to be robust with respect to uncertainties in the real parameters of the control design model such as uncertainties in the dimensional stability derivatives, imperfections in actuator/sensor locations and possibly variations in flight conditions, etc. The design is based on a new robust root clustering theory developed by the author by extending the nominal root clustering theory of Gutman and Jury to perturbed matrices. The proposed methodology allows to get an explicit relationship between the parameters of the root clustering region and the uncertainty radius of the parameter space. The current literature available for robust stability becomes a special case of this unified theory. The bounds derived on the parameter perturbation for robust root clustering are then used in selecting the robust controller.

Jammed Clusters and Non-locality in Dense Granular Flows

NASA Astrophysics Data System (ADS)

Kharel, Prashidha; Rognon, Pierre

We investigate the micro-mechanisms underpinning dense granular flow behaviour from a series of DEM simulations of pure shear flows of dry grains. We observe the development of transient clusters of jammed particles within the flow. Typical size of such clusters is found to scale with the inertial number with a power law that is similar to the scaling of shear-rate profile relaxation lengths observed previously. Based on the simple argument that transient clusters of size l exist in the dense flow regime, the formulation of steady state condition for non-homogeneous shear flow results in a general non-local relation, which is similar in form to the non-local relation conjectured for soft glassy flows. These findings suggest the formation of jammed clusters to be the key micro-mechanism underpinning non-local behaviour in dense granular flows. Particles and Grains Laboratory, School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia.

The BUFFALO HST Survey

NASA Astrophysics Data System (ADS)

Steinhardt, Charles; Jauzac, Mathilde; Capak, Peter; Koekemoer, Anton; Oesch, Pascal; Richard, Johan; Sharon, Keren q.; BUFFALO

2018-01-01

Beyond Ultra-deep Frontier Fields And Legacy Observations (BUFFALO) is an astronomical survey built around the six Hubble Space Telescope (HST) Frontier Fields clusters designed to learn about early galactic assembly and clustering and prepare targets for observations with the James Webb Space Telescope. BUFFALO will place significant new constraints on how and when the most massive and luminous galaxies in the universe formed and how early galaxy formation is linked to dark matter assembly. The same data will also probe the temperature and cross section of dark matter in the massive Frontier Fields galaxy clusters, and tell us how the dark matter, cluster gas, and dynamics of the clusters influence the galaxies in and around them. These studies are possible because the Spitzer Space Telescope, Chandra X-ray Observatory, XMM-Newton, and ground based telescopes have already invested heavily in deep observations around the Frontier Fields, so that the addition of HST observations can yield significant new results.

Dating star clusters in the Small Magellanic Cloud by means of integrated spectra

NASA Astrophysics Data System (ADS)

Ahumada, A. V.; Clariá, J. J.; Bica, E.; Dutra, C. M.

2002-10-01

In this study flux-calibrated integrated spectra in the range (3600-6800) Å are presented for 16 concentrated star clusters in the Small Magellanic Cloud (SMC), approximately half of which constitute unstudied objects. We have estimated ages and foreground interstellar reddening values from the comparison of the line strengths and continuum distribution of the cluster spectra with those of template cluster spectra with known parameters. Most of the sample clusters are young blue clusters (6-50 Myr), while L 28, NGC 643 and L 114 are found to be intermediate-age clusters (1-6 Gyr). One well known SMC cluster (NGC 416) was observed for comparison purposes. The sample includes clusters in the surroundings and main body of the SMC, and the derived foreground reddening values are in the range 0.00 <= E(B-V) <= 0.15. The present data also make up a cluster spectral library at SMC metallicity. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan, Argentina.

Waning immunity against mumps in vaccinated young adults, France 2013.

PubMed

Vygen, Sabine; Fischer, Aurélie; Meurice, Laure; Mounchetrou Njoya, Ibrahim; Gregoris, Marina; Ndiaye, Bakhao; Ghenassia, Adrien; Poujol, Isabelle; Stahl, Jean Paul; Antona, Denise; Le Strat, Yann; Levy-Bruhl, Daniel; Rolland, Patrick

2016-01-01

In 2013, 15 clusters of mumps were notified in France; 72% (82/114) of the cases had been vaccinated twice with measles-mumps-rubella vaccine. To determine whether the risk of mumps increased with time since the last vaccination, we conducted a case-control study among clusters in universities and military barracks. A confirmed case had an inflammation of a salivary gland plus laboratory confirmation in 2013. A probable case presented with inflammation of a salivary gland in 2013 either lasting for > 2 days or with epidemiological link to a confirmed case. Controls had no mumps symptoms and attended the same university course, student party or military barracks. We collected clinical and vaccination data via web questionnaire and medical records. We calculated adjusted odds ratios (aOR) using logistic regression. 59% (50/85) of cases and 62% (199/321) of controls had been vaccinated twice. The odds of mumps increased for twice-vaccinated individuals by 10% for every year that had passed since the second dose (aOR 1.10; 95% confidence interval (CI): 1.02-1.19; p = 0.02). Mumps immunity waned with increasing time since vaccination. Our findings contributed to the French High Council of Public Health's decision to recommend a third MMR dose during outbreaks for individuals whose second dose dates > 10 years.

Cluster Analysis to Identify Possible Subgroups in Tinnitus Patients.

PubMed

van den Berge, Minke J C; Free, Rolien H; Arnold, Rosemarie; de Kleine, Emile; Hofman, Rutger; van Dijk, J Marc C; van Dijk, Pim

2017-01-01

In tinnitus treatment, there is a tendency to shift from a "one size fits all" to a more individual, patient-tailored approach. Insight in the heterogeneity of the tinnitus spectrum might improve the management of tinnitus patients in terms of choice of treatment and identification of patients with severe mental distress. The goal of this study was to identify subgroups in a large group of tinnitus patients. Data were collected from patients with severe tinnitus complaints visiting our tertiary referral tinnitus care group at the University Medical Center Groningen. Patient-reported and physician-reported variables were collected during their visit to our clinic. Cluster analyses were used to characterize subgroups. For the selection of the right variables to enter in the cluster analysis, two approaches were used: (1) variable reduction with principle component analysis and (2) variable selection based on expert opinion. Various variables of 1,783 tinnitus patients were included in the analyses. Cluster analysis (1) included 976 patients and resulted in a four-cluster solution. The effect of external influences was the most discriminative between the groups, or clusters, of patients. The "silhouette measure" of the cluster outcome was low (0.2), indicating a "no substantial" cluster structure. Cluster analysis (2) included 761 patients and resulted in a three-cluster solution, comparable to the first analysis. Again, a "no substantial" cluster structure was found (0.2). Two cluster analyses on a large database of tinnitus patients revealed that clusters of patients are mostly formed by a different response of external influences on their disease. However, both cluster outcomes based on this dataset showed a poor stability, suggesting that our tinnitus population comprises a continuum rather than a number of clearly defined subgroups.

A systematic approach to the Kansei factors of tactile sense regarding the surface roughness.

PubMed

Choi, Kyungmee; Jun, Changrim

2007-01-01

Designing products to satisfy customers' emotion requires the information gathered through the human senses, which are visual, auditory, olfactory, gustatory, or tactile senses. By controlling certain design factors, customers' emotion can be evaluated, designed, and satisfied. In this study, a systematic approach is proposed to study the tactile sense regarding the surface roughness. Numerous pairs of antonymous tactile adjectives are collected and clustered. The optimal number of adjective clusters is estimated based on the several criterion functions. The representative average preferences of the final clusters are obtained as the estimates of engineering parameters to control the surface roughness of the commercial polymer-based products.

West Virginia US Department of Energy experimental program to stimulate competitive research. Section 2: Human resource development; Section 3: Carbon-based structural materials research cluster; Section 3: Data parallel algorithms for scientific computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-02-02

This report consists of three separate but related reports. They are (1) Human Resource Development, (2) Carbon-based Structural Materials Research Cluster, and (3) Data Parallel Algorithms for Scientific Computing. To meet the objectives of the Human Resource Development plan, the plan includes K--12 enrichment activities, undergraduate research opportunities for students at the state`s two Historically Black Colleges and Universities, graduate research through cluster assistantships and through a traineeship program targeted specifically to minorities, women and the disabled, and faculty development through participation in research clusters. One research cluster is the chemistry and physics of carbon-based materials. The objective of thismore » cluster is to develop a self-sustaining group of researchers in carbon-based materials research within the institutions of higher education in the state of West Virginia. The projects will involve analysis of cokes, graphites and other carbons in order to understand the properties that provide desirable structural characteristics including resistance to oxidation, levels of anisotropy and structural characteristics of the carbons themselves. In the proposed cluster on parallel algorithms, research by four WVU faculty and three state liberal arts college faculty are: (1) modeling of self-organized critical systems by cellular automata; (2) multiprefix algorithms and fat-free embeddings; (3) offline and online partitioning of data computation; and (4) manipulating and rendering three dimensional objects. This cluster furthers the state Experimental Program to Stimulate Competitive Research plan by building on existing strengths at WVU in parallel algorithms.« less

The gravitational-optical methods for examination of the hypothesis about galaxies and antigalaxies in the Universe

NASA Astrophysics Data System (ADS)

Gribov, I. A.; Trigger, S. A.

2018-01-01

The optical-gravitational methods for distinction between photons and antiphotons (galaxies, emitting photons and antigalaxies, emitting antiphotons) in the proposed hypothesis of totally gravitationally neutral (TGN)-Universe are considered. These methods are based on the extension of the earlier proposed the gravitationally neutral Universe concept, including now gravitational neutrality of vacuum. This concept contains (i) enlarged unbroken baryon-like, charge, parity and time and full ±M gr gravitational symmetries between all massive elementary particles-antiparticles, including (ia) ordinary matter (OM)-ordinary antimatter (OAM), (ib) dark matter (DM)-dark antimatter (DAM) and (ii) the resulting gravitational repulsion between equally presented (OM+DM)-galactic and (OAM+DAM)-antigalactic clusters, what spatially isolates and preserves their mutual annihilations in the large-scale TGN-Universe. It is assumed the gravitational balance not only between positive and negative gravitational masses of elementary particles and antiparticles, but also between all massless fields of the quantum field theory (QFT), including the opposite gravitational properties of photons and antiphotons, etc, realizing the totally gravitationally neutral vacuum in the QFT. These photons and antiphotons could be distinguishable optically-gravitationally, if one can observe a massive, deviating OM-star or a deviating (OM+DM)-galaxy from our galactic group, moving fast enough on the heavenly sphere, crossing the line directed to spatially separated far-remote galactic clusters (with the visible OM-markers, emitting photons) or antigalactic cluster (with the visible OAM-markers, emitting antiphotons). The deviations and gravitational microlensing with temporarily increased or decreased brightness of their OM and OAM rays will be opposite, indicating the galaxies and antigalaxies in the Universe.

A cluster randomised controlled trial to determine the effect of community mobilisation and advocacy on men's use of violence in periurban South Africa: study protocol.

PubMed

Christofides, Nicola J; Hatcher, Abigail M; Pino, Angelica; Rebombo, Dumisani; McBride, Ruari Santiago; Anderson, Althea; Peacock, Dean

2018-03-23

This paper describes the design and methods of a cluster randomised controlled trial (C-RCT) to determine the effectiveness of a community mobilisation intervention that is designed to reduce the perpetration of violence against women (VAW). A C-RCT of nine intervention and nine control clusters is being carried out in a periurban, semiformal settlement near Johannesburg, South Africa, between 2016 and 2018. A community mobilisation and advocacy intervention, called Sonke CHANGE is being implemented over 18 months. It comprises local advocacy and group activities to engage community members to challenge harmful gender norms and reduce VAW. The intervention is hypothesised to improve equitable masculinities, reduce alcohol use and ultimately, to reduce VAW. Intervention effectiveness will be determined through an audio computer-assisted self-interview questionnaire with behavioural measures among 2600 men aged between 18 and 40 years at baseline, 12 months and 24 months. The primary trial outcome is men's use of physical and/or sexual VAW. Secondary outcomes include harmful alcohol use, gender attitudes, controlling behaviours, transactional sex and social cohesion. The main analysis will be intention-to-treat based on the randomisation of clusters. A qualitative process evaluation is being conducted alongside the C-RCT. Implementers and men participating in the intervention will be interviewed longitudinally over the period of intervention implementation and observations of the workshops and other intervention activities are being carried out. Ethical approval was obtained from the University of the Witwatersrand Human Research Ethics Committee and procedures comply with ethical recommendations of the United Nations Multi-Country Study on Men and Violence. Dissemination of research findings will take place with local stakeholders and through peer-reviewed publications, with data available on request or after 5 years of trial completion. NCT02823288; Pre-result. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Controlling transformations in the assembly of polyoxometalate clusters: {Mo11V7}, {Mo17V8} and {Mo72V30}.

PubMed

Miras, Haralampos N; Ochoa, M Nieves Corella; Long, De-Liang; Cronin, Leroy

2010-11-21

The reaction of molybdate with vanadium(V) in the presence of sulfite anions is explored showing how, via cation control, stepwise assembly through the {Mo(11)V(7)} cluster yields a {M(25)} cluster-based compound, [Mo(VI)(11)V(V)(5)V(IV)(2)O(52)(μ(9)-SO(3))(Mo(VI)(6)V(V)O(22))](10-) (1a), which was first discovered using cryospray mass spectrometry, whereas switching the cation away from ammonium allows the direct formation of the spherical 'Keplerate' {Mo(72)V(30)} cluster.

Diffuse Optical Intracluster Light as a Measure of Stellar Tidal Stripping: The Cluster CL0024+17 at z ~ 0.4 Observed at the Large Binocular Telescope

NASA Astrophysics Data System (ADS)

Giallongo, E.; Menci, N.; Grazian, A.; Gallozzi, S.; Castellano, M.; Fiore, F.; Fontana, A.; Pentericci, L.; Boutsia, K.; Paris, D.; Speziali, R.; Testa, V.

2014-01-01

We have evaluated the diffuse intracluster light (ICL) in the central core of the galaxy cluster CL0024+17 at z ~ 0.4 observed with the prime focus camera (Large Binocular Camera) at the Large Binocular Telescope. The measure required an accurate removal of the galaxies' light within ~200 kpc from the center. The residual background intensity has then been integrated in circular apertures to derive the average ICL intensity profile. The latter shows an approximate exponential decline as expected from theoretical cold dark matter models where the ICL is due to the integrated contribution of light from stars that are tidally stripped from the halo of their host galaxies due to encounters with other galaxies in the cluster cold dark matter (CDM) potential. The radial profile of the ICL over the galaxies intensity ratio (ICL fraction) is increasing with decreasing radius, but near the cluster center it starts to bend and then decreases where the overlap of the halos of the brightest cluster galaxies becomes dominant. Theoretical expectations in a simplified CDM scenario show that the ICL fraction profile can be estimated from the stripped over galaxy stellar mass ratio in the cluster. It is possible to show that the latter quantity is almost independent of the properties of the individual host galaxies but mainly depends on the average cluster properties. The predicted ICL fraction profile is thus very sensitive to the assumed CDM profile, total mass, and concentration parameter of the cluster. Adopting values very similar to those derived from the most recent lensing analysis in CL0024+17, we find a good agreement with the observed ICL fraction profile. The galaxy counts in the cluster core have then been compared with that derived from composite cluster samples in larger volumes, up to the clusters virial radius. The galaxy counts in the CL0024+17 core appear flatter and the amount of bending with respect to the average cluster galaxy counts imply a loss of total emissivity in broad agreement with the measured ICL fraction. The present analysis shows that the measure of the ICL fraction in clusters can quantitatively account for the stellar stripping activity in their cores and can be used to probe their CDM distribution and evolutionary status. Observations have been carried out using the Large Binocular Telescope at Mt. Graham, AZ. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; the Ohio State University; and The Research Corporation, on behalf of the University of Notre Dame, University of Minnesota, and University of Virginia.

Consensus of satellite cluster flight using an energy-matching optimal control method

NASA Astrophysics Data System (ADS)

Luo, Jianjun; Zhou, Liang; Zhang, Bo

2017-11-01

This paper presents an optimal control method for consensus of satellite cluster flight under a kind of energy matching condition. Firstly, the relation between energy matching and satellite periodically bounded relative motion is analyzed, and the satellite energy matching principle is applied to configure the initial conditions. Then, period-delayed errors are adopted as state variables to establish the period-delayed errors dynamics models of a single satellite and the cluster. Next a novel satellite cluster feedback control protocol with coupling gain is designed, so that the satellite cluster periodically bounded relative motion consensus problem (period-delayed errors state consensus problem) is transformed to the stability of a set of matrices with the same low dimension. Based on the consensus region theory in the research of multi-agent system consensus issues, the coupling gain can be obtained to satisfy the requirement of consensus region and decouple the satellite cluster information topology and the feedback control gain matrix, which can be determined by Linear quadratic regulator (LQR) optimal method. This method can realize the consensus of satellite cluster period-delayed errors, leading to the consistency of semi-major axes (SMA) and the energy-matching of satellite cluster. Then satellites can emerge the global coordinative cluster behavior. Finally the feasibility and effectiveness of the present energy-matching optimal consensus for satellite cluster flight is verified through numerical simulations.

GibbsCluster: unsupervised clustering and alignment of peptide sequences.

PubMed

Andreatta, Massimo; Alvarez, Bruno; Nielsen, Morten

2017-07-03

Receptor interactions with short linear peptide fragments (ligands) are at the base of many biological signaling processes. Conserved and information-rich amino acid patterns, commonly called sequence motifs, shape and regulate these interactions. Because of the properties of a receptor-ligand system or of the assay used to interrogate it, experimental data often contain multiple sequence motifs. GibbsCluster is a powerful tool for unsupervised motif discovery because it can simultaneously cluster and align peptide data. The GibbsCluster 2.0 presented here is an improved version incorporating insertion and deletions accounting for variations in motif length in the peptide input. In basic terms, the program takes as input a set of peptide sequences and clusters them into meaningful groups. It returns the optimal number of clusters it identified, together with the sequence alignment and sequence motif characterizing each cluster. Several parameters are available to customize cluster analysis, including adjustable penalties for small clusters and overlapping groups and a trash cluster to remove outliers. As an example application, we used the server to deconvolute multiple specificities in large-scale peptidome data generated by mass spectrometry. The server is available at http://www.cbs.dtu.dk/services/GibbsCluster-2.0. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Effectiveness of a pragmatic school-based universal resilience intervention in reducing tobacco, alcohol and illicit substance use in a population of adolescents: cluster-randomised controlled trial.

PubMed

Hodder, Rebecca Kate; Freund, Megan; Bowman, Jenny; Wolfenden, Luke; Campbell, Elizabeth; Dray, Julia; Lecathelinais, Christophe; Oldmeadow, Christopher; Attia, John; Wiggers, John

2017-08-18

Initiation of tobacco, alcohol and illicit substance use typically occurs during adolescence, with the school setting recommended to reduce adolescent substance use. Strengthening individual (eg, problem solving) and environmental (eg, caring relationships at school) resilience protective factors of adolescents has been suggested as a strategy for reducing substance use by adolescents; however, few studies have examined this potential. A study was conducted to investigate the effectiveness of a pragmatic school-based universal 'resilience' intervention in reducing the prevalence of tobacco, alcohol and illicit substance use, and increasing the individual and environmental protective factors of students. A cluster-randomised controlled trial. Thirty-two Australian secondary schools (20 intervention; 12 control). Cohort of grade 7 students followed-up in grade 10 (2014; aged 15-16 years). A pragmatic intervention involving school staff selection and implementation of available programmes and resources targeting individual and environmental 'resilience' protective factors for all grade 7-10 students was implemented in schools (2012-2014). School staff were provided implementation support. An online survey collected baseline and follow-up data for primary outcomes: tobacco (ever, recent) and alcohol (ever, recent, 'risk') use, and secondary outcomes: marijuana and other illicit substance use, and individual (six-factor subscales, aggregate) and environmental (three-factor subscales, aggregate) protective factor scores. Generalised and linear mixed models examined follow-up differences between groups. Follow-up data from 2105 students (intervention=1261; control=844; 69% of baseline cohort) were analysed. No significant differences were found between intervention and control students for any primary (ever tobacco: OR 1.25, 95% CI 0.92 to 1.68, p=0.14; recent tobacco: OR 1.39, 95% CI 0.84 to 2.31, p=0.19; recent ever alcohol: OR 1.11, 95% CI 0.83 to 1.48, p=0.46; alcohol: OR 1.13, 95% CI 0.78 to 1.62, p=0.51; 'risk' alcohol: OR 0.98, 95% CI 0.70 to 1.36, p=0.89) or secondary outcomes (marijuana: OR 1.12, 95% CI 0.74 to 1.68, p=0.57; other illicit substance: OR 1.19, 95% CI 0.67 to 2.10, p=0.54; individual protective factors: MD=0, 95% CI -0.07 to 0.06, p=0.89; environmental protective factors: MD: -0.02, 95% CI -0.09 to 0.06, p=0.65). The universally implemented pragmatic school-based intervention was not effective in reducing the prevalence of tobacco, alcohol or illicit substance use, or in increasing the protective factors of students. Australia and New Zealand Clinical Trials Register reference: ACTRN12611000606987. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effectiveness of a pragmatic school-based universal resilience intervention in reducing tobacco, alcohol and illicit substance use in a population of adolescents: cluster-randomised controlled trial

PubMed Central

Freund, Megan; Bowman, Jenny; Campbell, Elizabeth; Dray, Julia; Lecathelinais, Christophe; Oldmeadow, Christopher; Attia, John; Wiggers, John

2017-01-01

Objectives Initiation of tobacco, alcohol and illicit substance use typically occurs during adolescence, with the school setting recommended to reduce adolescent substance use. Strengthening individual (eg, problem solving) and environmental (eg, caring relationships at school) resilience protective factors of adolescents has been suggested as a strategy for reducing substance use by adolescents; however, few studies have examined this potential. A study was conducted to investigate the effectiveness of a pragmatic school-based universal ‘resilience’ intervention in reducing the prevalence of tobacco, alcohol and illicit substance use, and increasing the individual and environmental protective factors of students. Design A cluster-randomised controlled trial. Setting Thirty-two Australian secondary schools (20 intervention; 12 control). Participants Cohort of grade 7 students followed-up in grade 10 (2014; aged 15–16 years). Intervention A pragmatic intervention involving school staff selection and implementation of available programmes and resources targeting individual and environmental ‘resilience’ protective factors for all grade 7–10 students was implemented in schools (2012–2014). School staff were provided implementation support. Measurements An online survey collected baseline and follow-up data for primary outcomes: tobacco (ever, recent) and alcohol (ever, recent, ‘risk’) use, and secondary outcomes: marijuana and other illicit substance use, and individual (six-factor subscales, aggregate) and environmental (three-factor subscales, aggregate) protective factor scores. Generalised and linear mixed models examined follow-up differences between groups. Results Follow-up data from 2105 students (intervention=1261; control=844; 69% of baseline cohort) were analysed. No significant differences were found between intervention and control students for any primary (ever tobacco: OR 1.25, 95% CI 0.92 to 1.68, p=0.14; recent tobacco: OR 1.39, 95% CI 0.84 to 2.31, p=0.19; recent ever alcohol: OR 1.11, 95% CI 0.83 to 1.48, p=0.46; alcohol: OR 1.13, 95% CI 0.78 to 1.62, p=0.51; ‘risk’ alcohol: OR 0.98, 95% CI 0.70 to 1.36, p=0.89) or secondary outcomes (marijuana: OR 1.12, 95% CI 0.74 to 1.68, p=0.57; other illicit substance: OR 1.19, 95% CI 0.67 to 2.10, p=0.54; individual protective factors: MD=0, 95% CI −0.07 to 0.06, p=0.89; environmental protective factors: MD: −0.02, 95% CI −0.09 to 0.06, p=0.65). Conclusions The universally implemented pragmatic school-based intervention was not effective in reducing the prevalence of tobacco, alcohol or illicit substance use, or in increasing the protective factors of students. Trial registration Australia and New Zealand Clinical Trials Register reference: ACTRN12611000606987 PMID:28821523

Fierz Convergence Criterion: A Controlled Approach to Strongly Interacting Systems with Small Embedded Clusters.

PubMed

Ayral, Thomas; Vučičević, Jaksa; Parcollet, Olivier

2017-10-20

We present an embedded-cluster method, based on the triply irreducible local expansion formalism. It turns the Fierz ambiguity, inherent to approaches based on a bosonic decoupling of local fermionic interactions, into a convergence criterion. It is based on the approximation of the three-leg vertex by a coarse-grained vertex computed from a self-consistently determined cluster impurity model. The computed self-energies are, by construction, continuous functions of momentum. We show that, in three interaction and doping regimes of the two-dimensional Hubbard model, self-energies obtained with clusters of size four only are very close to numerically exact benchmark results. We show that the Fierz parameter, which parametrizes the freedom in the Hubbard-Stratonovich decoupling, can be used as a quality control parameter. By contrast, the GW+extended dynamical mean field theory approximation with four cluster sites is shown to yield good results only in the weak-coupling regime and for a particular decoupling. Finally, we show that the vertex has spatially nonlocal components only at low Matsubara frequencies.

The DAFT/FADA survey. I. Photometric redshifts along lines of sight to clusters in the z = [0.4, 0.9] interval

NASA Astrophysics Data System (ADS)

Guennou, L.; Adami, C.; Ulmer, M. P.; Lebrun, V.; Durret, F.; Johnston, D.; Ilbert, O.; Clowe, D.; Gavazzi, R.; Murphy, K.; Schrabback, T.; Allam, S.; Annis, J.; Basa, S.; Benoist, C.; Biviano, A.; Cappi, A.; Kubo, J. M.; Marshall, P.; Mazure, A.; Rostagni, F.; Russeil, D.; Slezak, E.

2010-11-01

Context. As a contribution to the understanding of the dark energy concept, the Dark energy American French Team (DAFT, in French FADA) has started a large project to characterize statistically high redshift galaxy clusters, infer cosmological constraints from weak lensing tomography, and understand biases relevant for constraining dark energy and cluster physics in future cluster and cosmological experiments. Aims: The purpose of this paper is to establish the basis of reference for the photo-z determination used in all our subsequent papers, including weak lensing tomography studies. Methods: This project is based on a sample of 91 high redshift (z ≥ 0.4), massive (⪆3 × 1014 M_⊙) clusters with existing HST imaging, for which we are presently performing complementary multi-wavelength imaging. This allows us in particular to estimate spectral types and determine accurate photometric redshifts for galaxies along the lines of sight to the first ten clusters for which all the required data are available down to a limit of IAB = 24./24.5 with the LePhare software. The accuracy in redshift is of the order of 0.05 for the range 0.2 ≤ z ≤ 1.5. Results: We verified that the technique applied to obtain photometric redshifts works well by comparing our results to with previous works. In clusters, photo-z accuracy is degraded for bright absolute magnitudes and for the latest and earliest type galaxies. The photo-z accuracy also only slightly varies as a function of the spectral type for field galaxies. As a consequence, we find evidence for an environmental dependence of the photo-z accuracy, interpreted as the standard used spectral energy distributions being not very well suited to cluster galaxies. Finally, we modeled the LCDCS 0504 mass with the strong arcs detected along this line of sight. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Institute and the Space Telescope European Coordinating Facility. STScI is operated by the association of Universities for Research in Astronomy, Inc. under the NASA contract NAS 5-26555. Also based on observations made with ESO Telescopes at Paranal and La Silla Observatories under programme ESO LP 166.A-0162. Also based on visiting astronomer observations, at Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation.

Social and Emotional Learning Services and Child Outcomes in Third Grade: Evidence from a Cohort of Head Start Participants.

PubMed

Zhai, Fuhua; Raver, C Cybele; Jones, Stephanie M

2015-09-01

A variety of universal school-based social and emotional learning (SEL) programs have been designed in the past decades to help children improve social-emotional and academic skills. Evidence on the effectiveness of SEL programs has been mixed in the literature. Using data from a longitudinal follow-up study of children (n = 414) originally enrolled in a clustered randomized controlled trial (RCT) when they were in Head Start, we examined whether universal SEL services in third grade were associated with the development of children from disadvantaged families. We took advantage of pairwise matching in the RCT design to compare children who had similar family background and preschool experiences but received different doses of SEL services in third grade. The results showed that the frequent (i.e., weekly to daily) exposure to SEL opportunities was associated with favorable social-emotional and academic development in third grade, including increased social skills, student-teacher relationship, and academic skills, as well as reduced impulsiveness.

Classroom Promotion of Oral Language (CPOL): protocol for a cluster randomised controlled trial of a school-based intervention to improve children’s literacy outcomes at grade 3, oral language and mental health

PubMed Central

Goldfeld, Sharon; Snow, Pamela; Eadie, Patricia; Munro, John; Gold, Lisa; Le, Ha N D; Orsini, Francesca; Shingles, Beth; Lee, Katherine; Connell, Judy; Watts, Amy

2017-01-01

Introduction Oral language and literacy competence are major influences on children’s developmental pathways and life success. Children who do not develop the necessary language and literacy skills in the early years of school then go on to face long-term difficulties. Improving teacher effectiveness may be a critical step in lifting oral language and literacy outcomes. The Classroom Promotion of Oral Language trial aims to determine whether a specifically designed teacher professional learning programme focusing on promoting oral language can lead to improved teacher knowledge and practice, and advance outcomes in oral language and literacy for early years school children, compared with usual practice. Methods and analysis This is a two-arm cluster multisite randomised controlled trial conducted within Catholic and Government primary schools across Victoria, Australia. The intervention comprises 4 days of face-to-face professional learning for teachers and ongoing implementation support via a specific worker. The primary outcome is reading ability of the students at grade 3, and the secondary outcomes are teacher knowledge and practice, student mental health, reading comprehension and language ability at grade 1; and literacy, writing and numeracy at grade 3. Economic evaluation will compare the incremental costs of the intervention to the measured primary and secondary outcomes. Ethics and dissemination This trial was approved by the Monash University Human Research Ethics Committee #CF13/2634-2013001403 and later transferred to the University of Melbourne #1545540. The investigators (including Government and Catholic partners) will communicate trial results to stakeholders, collaborators and participating schools and teachers via appropriate presentations and publications. Trial registration number ISRCTN77681972; Pre-results. PMID:29162571

Map-based trigonometric parallaxes of open clusters - The Pleiades

NASA Technical Reports Server (NTRS)

Gatewood, George; Castelaz, Michael; Han, Inwoo; Persinger, Timothy; Stein, John

1990-01-01

The multichannel astrometric photometer and Thaw refractor of the University of Pittsburgh's Allegheny Observatory have been used to determine the trigonometric parallax of the Pleiades star cluster. The distance determined, 150 with a standard error of 18 parsecs, places the cluster slightly farther away than generally accepted. This suggests that the basis of many estimations of the cosmic distance scale is approximately 20 percent short. The accuracy of the determination is limited by the number and choice of reference stars. With careful attention to the selection of reference stars in several Pleiades regions, it should be possible to examine differences in the photometric and trigonometric modulus at a precision of 0.1 magnitudes.

Study protocol for a self-controlled cluster randomised trial of the Alert Program to improve self-regulation and executive function in Australian Aboriginal children with fetal alcohol spectrum disorder

PubMed Central

Fitzpatrick, James P; Mazzucchelli, Trevor G; Symons, Martyn; Carmichael Olson, Heather; Jirikowic, Tracy; Cross, Donna; Wright, Edie; Adams, Emma; Carter, Maureen; Bruce, Kaashifah; Latimer, Jane

2018-01-01

Introduction While research highlights the benefits of early diagnosis and intervention for children with fetal alcohol spectrum disorders (FASD), there are limited data documenting effective interventions for Australian children living in remote communities. Methods and analysis This self-controlled cluster randomised trial is evaluating the effectiveness of an 8-week Alert Program school curriculum for improving self-regulation and executive function in children living in remote Australian Aboriginal communities. Children in grades 1–6 attending any of the eight participating schools across the Fitzroy Valley in remote North-West Australia (N ≈ 363) were invited to participate. Each school was assigned to one of four clusters with clusters randomly assigned to receive the intervention at one of four time points. Clusters two, three and four had extended control conditions where students received regular schooling before later receiving the intervention. Trained classroom teachers delivered the Alert Program to students in discrete, weekly, 1-hour lessons. Student outcomes were assessed at three time points. For the intervention condition, data collection occurred 2 weeks immediately before and after the intervention, with a follow-up 8 weeks later. For control conditions in clusters two to four, the control data collection matched that of the data collection for the intervention condition in the preceding cluster. The primary outcome is change in self-regulation. FASD diagnoses will be determined via medical record review after the completion of data collection. The results will be analysed using generalised linear mixed modelling and reported in accordance with Consolidated Standards of Reporting Trials (CONSORT) guidelines. Ethics and dissemination Ethical approval was obtained from the University of Western Australia (WA) (RA/4/1/7234), WA Aboriginal Health Ethics Committee (601) and WA Country Health Service (2015:04). The Kimberley Aboriginal Health Planning Forum Research Sub-Committee and WA Department of Education also provided approval. The results will be disseminated through peer-reviewed journals, conference presentations, the media and at forums. Trial registration number ACTRN12615000733572; Pre-results. PMID:29581212

Promoting state health department evidence-based cancer and chronic disease prevention: a multi-phase dissemination study with a cluster randomized trial component

PubMed Central

2013-01-01

Background Cancer and other chronic diseases reduce quality and length of life and productivity, and represent a significant financial burden to society. Evidence-based public health approaches to prevent cancer and other chronic diseases have been identified in recent decades and have the potential for high impact. Yet, barriers to implement prevention approaches persist as a result of multiple factors including lack of organizational support, limited resources, competing emerging priorities and crises, and limited skill among the public health workforce. The purpose of this study is to learn how best to promote the adoption of evidence based public health practice related to chronic disease prevention. Methods/design This paper describes the methods for a multi-phase dissemination study with a cluster randomized trial component that will evaluate the dissemination of public health knowledge about evidence-based prevention of cancer and other chronic diseases. Phase one involves development of measures of practitioner views on and organizational supports for evidence-based public health and data collection using a national online survey involving state health department chronic disease practitioners. In phase two, a cluster randomized trial design will be conducted to test receptivity and usefulness of dissemination strategies directed toward state health department chronic disease practitioners to enhance capacity and organizational support for evidence-based chronic disease prevention. Twelve state health department chronic disease units will be randomly selected and assigned to intervention or control. State health department staff and the university-based study team will jointly identify, refine, and select dissemination strategies within intervention units. Intervention (dissemination) strategies may include multi-day in-person training workshops, electronic information exchange modalities, and remote technical assistance. Evaluation methods include pre-post surveys, structured qualitative phone interviews, and abstraction of state-level chronic disease prevention program plans and progress reports. Trial registration clinicaltrials.gov: NCT01978054. PMID:24330729

Universal screening and decolonization for control of MRSA in nursing homes: a cluster randomized controlled study.

PubMed

Bellini, Cristina; Petignat, Christiane; Masserey, Eric; Büla, Christophe; Burnand, Bernard; Rousson, Valentin; Blanc, Dominique S; Zanetti, Giorgio

2015-04-01

The risk of carrying methicillin-resistant Staphylococcus aureus (MRSA) is higher among nursing home (NH) residents than in the general population. However, control strategies are not clearly defined in this setting. In this study, we compared the impact of standard precautions either alone (control) or combined with screening of residents and decolonization of carriers (intervention) to control MRSA in NHs. Cluster randomized controlled trial. NHs of the state of Vaud, Switzerland. Of 157 total NHs in Vaud, 104 (67%) participated in the study. Standard precautions were enforced in all participating NHs, and residents underwent MRSA screening at baseline and 12 months thereafter. All carriers identified in intervention NHs, either at study entry or among newly admitted residents, underwent topical decolonization combined with environmental disinfection, except in cases of MRSA infection, MRSA bacteriuria, or deep skin ulcers. NHs were randomly allocated to a control group (51 NHs, 2,412 residents) or an intervention group (53 NHs, 2,338 residents). Characteristics of NHs and residents were similar in both groups. The mean screening rates were 86% (range, 27%-100%) in control NHs and 87% (20%-100%) in intervention NHs. Prevalence of MRSA carriage averaged 8.9% in both control NHs (range, 0%-43%) and intervention NHs (range, 0%-38%) at baseline, and this rate significantly declined to 6.6% in control NHs and to 5.8% in intervention NHs after 12 months. However, the decline did not differ between groups (P=.66). Universal screening followed by decolonization of carriers did not significantly reduce the prevalence of the MRSA carriage rate at 1 year compared with standard precautions.

Study protocol for the SMART2D adaptive implementation trial: a cluster randomised trial comparing facility-only care with integrated facility and community care to improve type 2 diabetes outcomes in Uganda, South Africa and Sweden.

PubMed

Guwatudde, David; Absetz, Pilvikki; Delobelle, Peter; Östenson, Claes-Göran; Olmen Van, Josefien; Alvesson, Helle Molsted; Mayega, Roy William; Ekirapa Kiracho, Elizabeth; Kiguli, Juliet; Sundberg, Carl Johan; Sanders, David; Tomson, Göran; Puoane, Thandi; Peterson, Stefan; Daivadanam, Meena

2018-03-17

Type 2 diabetes (T2D) is increasingly contributing to the global burden of disease. Health systems in most parts of the world are struggling to diagnose and manage T2D, especially in low-income and middle-income countries, and among disadvantaged populations in high-income countries. The aim of this study is to determine the added benefit of community interventions onto health facility interventions, towards glycaemic control among persons with diabetes, and towards reduction in plasma glucose among persons with prediabetes. An adaptive implementation cluster randomised trial is being implemented in two rural districts in Uganda with three clusters per study arm, in an urban township in South Africa with one cluster per study arm, and in socially disadvantaged suburbs in Stockholm, Sweden with one cluster per study arm. Clusters are communities within the catchment areas of participating primary healthcare facilities. There are two study arms comprising a facility plus community interventions arm and a facility-only interventions arm. Uganda has a third arm comprising usual care. Intervention strategies focus on organisation of care, linkage between health facility and the community, and strengthening patient role in self-management, community mobilisation and a supportive environment. Among T2D participants, the primary outcome is controlled plasma glucose; whereas among prediabetes participants the primary outcome is reduction in plasma glucose. The study has received approval in Uganda from the Higher Degrees, Research and Ethics Committee of Makerere University School of Public Health and from the Uganda National Council for Science and Technology; in South Africa from the Biomedical Science Research Ethics Committee of the University of the Western Cape; and in Sweden from the Regional Ethical Board in Stockholm. Findings will be disseminated through peer-reviewed publications and scientific meetings. ISRCTN11913581; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Images From Hubbles's ACS Tell A Tale Of Two Record-Breaking Galaxy Clusters

NASA Astrophysics Data System (ADS)

2004-01-01

Looking back in time nearly 9 billion years, an international team of astronomers found mature galaxies in a young universe. The galaxies are members of a cluster of galaxies that existed when the universe was only 5 billion years old, or about 35 percent of its present age. This compelling evidence that galaxies must have started forming just after the big bang was bolstered by observations made by the same team of astronomers when they peered even farther back in time. The team found embryonic galaxies a mere 1.5 billion years after the birth of the cosmos, or 10 percent of the universe's present age. The "baby galaxies" reside in a still-developing cluster, the most distant proto-cluster ever found. The Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope was used to make observations of the massive cluster, RDCS 1252.9-2927, and the proto-cluster, TN J1338-1942. Observations by NASA's Chandra X-ray Observatory yielded the mass and heavy element content of RDCS 1252, the most massive known cluster for that epoch. These observations are part of a coordinated effort by the ACS science team to track the formation and evolution of clusters of galaxies over a broad range of cosmic time. The ACS was built especially for studies of such distant objects. These findings further support observations and theories that galaxies formed relatively early in the history of the cosmos. The existence of such massive clusters in the early universe agrees with a cosmological model wherein clusters form from the merger of many sub-clusters in a universe dominated by cold dark matter. The precise nature of cold dark matter, however, is still not known. The first Hubble study estimated that galaxies in RDCS 1252 formed the bulk of their stars more than 11 billion years ago (at redshifts greater than 3). The results were published in the Oct. 20, 2003 issue of the Astrophysical Journal. The paper's lead author is John Blakeslee of the Johns Hopkins University in Baltimore, Md. Optical Image of RDCS 1252.9-2927 HST Optical Image of RDCS 1252.9-2927 The second Hubble study uncovered, for the first time, a proto-cluster of "infant galaxies" that existed more than 12 billion years ago (at redshift 4.1). These galaxies are so young that astronomers can still see a flurry of stars forming within them. The galaxies are grouped around one large galaxy. These results will be published in the Jan. 1, 2004 issue of Nature. The paper's lead author is George Miley of Leiden Observatory in the Netherlands. "Until recently people didn't think that clusters existed when the universe was only about 5 billion years old," Blakeslee explained. "Even if there were such clusters," Miley added, "until recently astronomers thought it was almost impossible to find clusters that existed 8 billion years ago. In fact, no one really knew when clustering began. Now we can witness it." Both studies led the astronomers to conclude that these systems are the progenitors of the galaxy clusters seen today. "The cluster RDCS 1252 looks like a present-day cluster," said Marc Postman of the Space Telescope Science Institute in Baltimore, Md., and co-author of both research papers. "In fact, if you were to put it next to a present-day cluster, you wouldn't know which is which." A Tale of Two Clusters How can galaxies grow so fast after the big bang? "It is a case of the rich getting richer," Blakeslee said. "These clusters grew quickly because they are located in very dense regions, so there is enough material to build up the member galaxies very fast." This idea is strengthened by X-ray observations of the massive cluster RDCS 1252. Chandra and the European Space Agency's XMM-Newton provided astronomers with the most accurate measurements to date of the properties of an enormous cloud of hot gas that pervades the massive cluster. This 160-million-degree Fahrenheit (70-million-degree Celsius) gas is a reservoir of most of the heavy elements in the cluster and an accurate tracer of its total mass. A paper by Piero Rosati of the European Southern Observatory (ESO) and colleagues that presents the X-ray observations of RDCS 1252 will be published in January 2004 in the Astronomical Journal. "Chandra's sharp vision resolved the shape of the hot gas halo and showed that RDCS 1252 is very mature for its age," said Rosati, who discovered the cluster with the ROSAT X-ray telescope. RDCS 1252 may contain many thousands of galaxies. Most of these galaxies, however, are too faint to detect. But the powerful "eyes" of the ACS pinpointed several hundred of them. Observations using ESO's Very Large Telescope (VLT) provided a precise measurement of the distance to the cluster. The ACS enabled the researchers to accurately determine the shapes and colors of the 100 galaxies, providing information on the ages of the stars residing in them. The ACS team estimated that most of the stars in the cluster were already formed when the universe was about 2 billion years old. X-ray observations, furthermore, showed that 5 billion years after the big bang the surrounding hot gas had been enriched with heavy elements from these stars and had been swept away from the galaxies. If most of the galaxies in RDCS 1252 have reached maturity and are settling into a quiet adulthood, the forming galaxies in the distant proto-cluster are in their energetic, unruly youth. The proto-cluster TN J1338 contains a massive embryonic galaxy surrounded by smaller developing galaxies, which look like dots in the Hubble image. The dominant galaxy is producing spectacular radio-emitting jets, fueled by a supermassive black hole deep within the galaxy's nucleus. Interaction between these jets and the gas can stimulate a torrent of star birth. The energetic radio galaxy's discovery by radio telescopes prompted astronomers to hunt for the smaller galaxies that make up the bulk of the cluster. "Massive clusters are the cities of the universe, and the radio galaxies within them are the smokestacks we can use for finding them when they are just beginning to form," Miley said. The two findings underscore the power of combining observations from many different telescopes that provided views of the distant universe in a range of wavelengths. Hubble's advanced camera provided critical information on the structure of both distant galaxy clusters. Chandra's and XMM-Newton's X-ray vision furnished the essential measurements of the primordial gas in which the galaxies in RDCS 1252 are embedded, and accurate estimates of the total mass contained within that cluster. Large ground-based telescopes, like the VLT, provided precise measurements of the distance of both clusters as well as the chemical composition of the galaxies in them. The ACS team is conducting further observations of distant clusters to solidify our understanding of how these young clusters and their galaxies evolve into the shape of things seen today. Their planned observations include using near-infrared observations to analyze the star-formation rates in some of the target clusters, including RDCS 1252, to measure the cosmic history of star formation in these massive structures. The team is also searching the regions around several ultra-distant radio galaxies for additional examples of proto-clusters. The team's ultimate scientific goal is to establish a complete picture of cluster evolution beginning with the formation at the earliest epochs and detailing the evolution up to today. Electronic image files and additional information are available at http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/01/ The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

Oldest Known Objects May Be Surprisingly Immature

NASA Astrophysics Data System (ADS)

2008-04-01

Some of the oldest objects in the Universe may still have a long way to go, according to a new study using NASA’s Chandra X-ray Observatory. These new results indicate that globular clusters might be surprisingly less mature in their development than previously thought. Globular clusters, dense bunches of up to millions of stars found in all galaxies, are among the oldest known objects in the Universe, with most estimates of their ages ranging from 9 to 13 billions of years old. As such they contain some of the first stars to form in a galaxy and understanding their evolution is critical to understanding the evolution of galaxies. Animation The Evolution of a Globular Cluster "For many years, globular clusters have been used as wonderful natural laboratories to study the evolution and interaction of stars," said John Fregeau of Northwestern University, who conducted the study. "So, it’s exciting to discover something that may be new and fundamental about the way they evolve." Conventional wisdom is that globular clusters pass through three phases of evolution or development of their structure, corresponding to adolescence, middle age, and old age. These "ages" refer to the evolutionary state of the cluster, not the physical ages of the individual stars. People Who Read This Also Read... Milky Way's Super-efficient Particle Accelerators Caught in The Act Discovery of Most Recent Supernova in Our Galaxy Action Replay of Powerful Stellar Explosion Jet Power and Black Hole Assortment Revealed in New Chandra Image In the adolescent phase, the stars near the center of the cluster collapse inward. Middle age refers to a phase when the interactions of double stars near the center of the cluster prevents it from further collapse. Finally, old age describes when binaries in the center of the cluster are disrupted or ejected, and the center of the cluster collapses inwards. For years, it has been thought that most globular clusters are middle- aged with a few being toward the end of their evolution. However, Chandra data along with theoretical work suggest this may not be the case. When single and double stars interact in the crowded centers of globular clusters, double stars can form that transfer mass and give off X-rays. Since such double stars are expected to mostly be formed in the middle of a globular cluster’s evolution and then lost in old age, the relative number of X-ray sources gives clues about the stage of evolution the cluster is in. A new study by Fregeau of 13 globular clusters in the Milky Way shows that three of them have unusually large number of X-ray sources, or X- ray binaries, suggesting the clusters are middle-aged. Previously, these globular clusters had been classified as being in old age because they had very tight concentrations of stars in their centers, another litmus test of age used by astronomers. The implication is that most globular clusters, including the other ten studied by Fregeau, are not in the middle age of their evolution, as previously thought, but are actually in adolescence. "It’s remarkable that these objects, which are thought to be some of the oldest in the Universe, may really be very immature in their development," said Fregeau whose paper appears in The Astrophysical Journal. "This would represent a major change in thinking about the current evolutionary status of globular clusters." If confirmed, this result would help reconcile other observations with recent theoretical work that suggest the tightness of the central concentration of stars in the most evolved globular clusters is consistent with them being in a middle, rather than an advanced phase of evolution. Other theoretical studies have suggested it can take longer than the current age of the Universe for globular clusters to reach old age. Besides improving the understanding of the basic evolution of globular clusters, this result has implications for understanding stellar interactions in dense environments. It also removes the need for exotic mechanisms - some involving black holes - that were thought to be needed to prevent the many middle-aged clusters from collapsing. "Some exotic scenarios, including some of my own, have been invoked to try to make sense of the observations and save the old theory," said Fregeau. "If this result holds up, we don't have to worry about the exotic scenarios any more." NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency’s Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Preventing mental health problems in children: the Families in Mind population-based cluster randomised controlled trial

PubMed Central

2012-01-01

Background Externalising and internalising problems affect one in seven school-aged children and are the single strongest predictor of mental health problems into early adolescence. As the burden of mental health problems persists globally, childhood prevention of mental health problems is paramount. Prevention can be offered to all children (universal) or to children at risk of developing mental health problems (targeted). The relative effectiveness and costs of a targeted only versus combined universal and targeted approach are unknown. This study aims to determine the effectiveness, costs and uptake of two approaches to early childhood prevention of mental health problems ie: a Combined universal-targeted approach, versus a Targeted only approach, in comparison to current primary care services (Usual care). Methods/design Three armed, population-level cluster randomised trial (2010–2014) within the universal, well child Maternal Child Health system, attended by more than 80% of families in Victoria, Australia at infant age eight months. Participants were families of eight month old children from nine participating local government areas. Randomised to one of three groups: Combined, Targeted or Usual care. The interventions comprises (a) the Combined universal and targeted program where all families are offered the universal Toddlers Without Tears group parenting program followed by the targeted Family Check-Up one-on-one program or (b) the Targeted Family Check-Up program. The Family Check-Up program is only offered to children at risk of behavioural problems. Participants will be analysed according to the trial arm to which they were randomised, using logistic and linear regression models to compare primary and secondary outcomes. An economic evaluation (cost consequences analysis) will compare incremental costs to all incremental outcomes from a societal perspective. Discussion This trial will inform public health policy by making recommendations about the effectiveness and cost-effectiveness of these early prevention programs. If effective prevention programs can be implemented at the population level, the growing burden of mental health problems could be curbed. Trial registration ISRCTN61137690 PMID:22682229

Children Learning About Second-Hand Smoking: A Feasibility Cluster Randomized Controlled Trial.

PubMed

Huque, Rumana; Dogar, Omara; Cameron, Ian; Thomson, Heather; Amos, Amanda; Siddiqi, Kamran

2015-12-01

Exposure to second-hand smoke is a threat to children's health. We developed a school-based smoke-free intervention (SFI) to support families in implementing smoke-free homes in Bangladesh, and gathered preliminary evidence of its effectiveness. A feasibility cluster randomized controlled trial of SFI was conducted in 24 schools in Mirpur, an urban area within Dhaka. Using simple stratified randomization, schools were allocated to: Arm A (SFI only), Arm B (SFI plus reminders), and Arm C (the control group). A total of 781 year-5 children (10-12 years old) in the consenting schools, participated in the study. Outcomes including "smoke-free homes" and "social visibility" that is, not smoking in front of children at home were assessed through questionnaire-based children's surveys, administered by researchers, at baseline and at weeks 1, 12, 27, and 52 in all arms. "Smoke-free homes" were significantly higher in Arm A (odds ratio [OR] = 4.8; 95% CI = 2.6-9.0) and in Arm B (OR = 3.9; 95% CI = 2.0-7.5) than in Arm C, when controlled for the baseline levels, at year 1. Similarly, "social visibility" was significantly reduced in Arm A (OR = 5.8; 95% CI = 2.8-11.7) and in Arm B (OR = 7.2; 95% CI = 3.3-15.9) than Arm C, when controlled for the baseline levels, at year 1. We observed an increasing trend (Cochrane Armitage test statistic [Z] = 3.8; p < .0001) in homes becoming smoke-free with increasing intensity of the intervention (control < Arm A < Arm B), and a decreasing trend (Z = -5.13; p < .0001) in social visibility at homes. SFI has the potential to encourage children to negotiate a smoke-free environment in their homes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The massive stellar population of W49: A spectroscopic survey

NASA Astrophysics Data System (ADS)

Wu, Shi-Wei; Bik, Arjan; Bestenlehner, Joachim M.; Henning, Thomas; Pasquali, Anna; Brandner, Wolfgang; Stolte, Andrea

2016-05-01

Context. Massive stars form on different scales that range from large, dispersed OB associations to compact, dense starburst clusters. The complex structure of regions of massive star formation and the involved short timescales provide a challenge for our understanding of their birth and early evolution. As one of the most massive and luminous star-forming region in our Galaxy, W49 is the ideal place to study the formation of the most massive stars. Aims: By classifying the massive young stars that are deeply embedded in the molecular cloud of W49, we aim to investigate and trace the star formation history of this region. Methods: We analyse near-infrared K-band spectroscopic observations of W49 from LBT/LUCI combined with JHK images obtained with NTT/SOFI and LBT/LUCI. Based on JHK-band photometry and K-band spectroscopy, the massive stars are placed in a Hertzsprung Russell diagram. By comparison with evolutionary models, their age and hence the star formation history of W49 can be investigated. Results: Fourteen O-type stars, as well as two young stellar objects (YSOs), are identified by our spectroscopic survey. Eleven O stars are main sequence stars with subtypes ranging from O3 to O9.5 and masses ranging from ~20 M⊙ to ~120 M⊙. Three of the O stars show strong wind features and are considered to be Of-type supergiants with masses beyond 100 M⊙. The two YSOs show CO emission, which is indicative of the presence of circumstellar disks in the central region of the massive cluster. The age of the cluster is estimated as ~1.5 Myr, with star formation continuing in different parts of the region. The ionising photons from the central massive stars have not yet cleared the molecular cocoon surrounding the cluster. W49 is comparable to extragalactic star-forming regions, and it provides us with a unique chance to study a starburst in detail. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in Germany, Italy and the United States. LBT Corporation partners are: LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; Istituto Nazionale di Astrofisica, Italy; The University of Arizona on behalf of the Arizona university system; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota and University of Virginia.Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme IDs 67.C-0514 and 073.D-0837.The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/589/A16

Leveraging contact network structure in the design of cluster randomized trials.

PubMed

Harling, Guy; Wang, Rui; Onnela, Jukka-Pekka; De Gruttola, Victor

2017-02-01

In settings like the Ebola epidemic, where proof-of-principle trials have provided evidence of efficacy but questions remain about the effectiveness of different possible modes of implementation, it may be useful to conduct trials that not only generate information about intervention effects but also themselves provide public health benefit. Cluster randomized trials are of particular value for infectious disease prevention research by virtue of their ability to capture both direct and indirect effects of intervention, the latter of which depends heavily on the nature of contact networks within and across clusters. By leveraging information about these networks-in particular the degree of connection across randomized units, which can be obtained at study baseline-we propose a novel class of connectivity-informed cluster trial designs that aim both to improve public health impact (speed of epidemic control) and to preserve the ability to detect intervention effects. We several designs for cluster randomized trials with staggered enrollment, in each of which the order of enrollment is based on the total number of ties (contacts) from individuals within a cluster to individuals in other clusters. Our designs can accommodate connectivity based either on the total number of external connections at baseline or on connections only to areas yet to receive the intervention. We further consider a "holdback" version of the designs in which control clusters are held back from re-randomization for some time interval. We investigate the performance of these designs in terms of epidemic control outcomes (time to end of epidemic and cumulative incidence) and power to detect intervention effect, by simulating vaccination trials during an SEIR-type epidemic outbreak using a network-structured agent-based model. We compare results to those of a traditional Stepped Wedge trial. In our simulation studies, connectivity-informed designs lead to a 20% reduction in cumulative incidence compared to comparable traditional study designs, but have little impact on epidemic length. Power to detect intervention effect is reduced in all connectivity-informed designs, but "holdback" versions provide power that is very close to that of a traditional Stepped Wedge approach. Incorporating information about cluster connectivity in the design of cluster randomized trials can increase their public health impact, especially in acute outbreak settings. Using this information helps control outbreaks-by minimizing the number of cross-cluster infections-with very modest cost in terms of power to detect effectiveness.

Dark energy domination in the Virgocentric flow

NASA Astrophysics Data System (ADS)

Chernin, A. D.; Karachentsev, I. D.; Nasonova, O. G.; Teerikorpi, P.; Valtonen, M. J.; Dolgachev, V. P.; Domozhilova, L. M.; Byrd, G. G.

2010-09-01

Context. The standard ΛCDM cosmological model implies that all celestial bodies are embedded in a perfectly uniform dark energy background, represented by Einstein's cosmological constant, and experience its repulsive antigravity action. Aims: Can dark energy have strong dynamical effects on small cosmic scales as well as globally? Continuing our efforts to clarify this question, we now focus on the Virgo Cluster and the flow of expansion around it. Methods: We interpret the Hubble diagram from a new database of velocities and distances of galaxies in the cluster and its environment, using a nonlinear analytical model, which incorporates the antigravity force in terms of Newtonian mechanics. The key parameter is the zero-gravity radius, the distance at which gravity and antigravity are in balance. Results: 1. The interplay between the gravity of the cluster and the antigravity of the dark energy background determines the kinematical structure of the system and controls its evolution. 2. The gravity dominates the quasi-stationary bound cluster, while the antigravity controls the Virgocentric flow, bringing order and regularity to the flow, which reaches linearity and the global Hubble rate at distances ⪆15 Mpc. 3. The cluster and the flow form a system similar to the Local Group and its outflow. In the velocity-distance diagram, the cluster-flow structure reproduces the group-flow structure with a scaling factor of about 10; the zero-gravity radius for the cluster system is also 10 times larger. Conclusions: The phase and dynamical similarity of the systems on the scales of 1-30 Mpc suggests that a two-component pattern may be universal for groups and clusters: a quasi-stationary bound central component and an expanding outflow around it, caused by the nonlinear gravity-antigravity interplay with the dark energy dominating in the flow component.

A Cluster Randomized Trial of the Social Skills Improvement System-Classwide Intervention Program (SSIS-CIP) in First Grade

ERIC Educational Resources Information Center

DiPerna, James Clyde; Lei, Puiwa; Cheng, Weiyi; Hart, Susan Crandall; Bellinger, Jillian

2018-01-01

The purpose of this study was to evaluate the efficacy of a universal social skills program, the Social Skills Improvement System Classwide Intervention Program (SSIS-CIP; Elliott & Gresham, 2007), for students in first grade. Classrooms from 6 elementary schools were randomly assigned to treatment or business-as-usual control conditions.…

Long-lasting insecticide-treated house screens and targeted treatment of productive breeding-sites for dengue vector control in Acapulco, Mexico

PubMed Central

Che-Mendoza, Azael; Guillermo-May, Guillermo; Herrera-Bojórquez, Josué; Barrera-Pérez, Mario; Dzul-Manzanilla, Felipe; Gutierrez-Castro, Cipriano; Arredondo-Jiménez, Juan I.; Sánchez-Tejeda, Gustavo; Vazquez-Prokopec, Gonzalo; Ranson, Hilary; Lenhart, Audrey; Sommerfeld, Johannes; McCall, Philip J.; Kroeger, Axel; Manrique-Saide, Pablo

2015-01-01

Background Long-lasting insecticidal net screens (LLIS) fitted to domestic windows and doors in combination with targeted treatment (TT) of the most productive Aedes aegypti breeding sites were evaluated for their impact on dengue vector indices in a cluster-randomised trial in Mexico between 2011 and 2013. Methods Sequentially over 2 years, LLIS and TT were deployed in 10 treatment clusters (100 houses/cluster) and followed up over 24 months. Cross-sectional surveys quantified infestations of adult mosquitoes, immature stages at baseline (pre-intervention) and in four post-intervention samples at 6-monthly intervals. Identical surveys were carried out in 10 control clusters that received no treatment. Results LLIS clusters had significantly lower infestations compared to control clusters at 5 and 12 months after installation, as measured by adult (male and female) and pupal-based vector indices. After addition of TT to the intervention houses in intervention clusters, indices remained significantly lower in the treated clusters until 18 (immature and adult stage indices) and 24 months (adult indices only) post-intervention. Conclusions These safe, simple affordable vector control tools were well-accepted by study participants and are potentially suitable in many regions at risk from dengue worldwide. PMID:25604761

Defective functional connectivity between posterior hypothalamus and regions of the diencephalic-mesencephalic junction in chronic cluster headache.

PubMed

Ferraro, Stefania; Nigri, Anna; Bruzzone, Maria Grazia; Brivio, Luca; Proietti Cecchini, Alberto; Verri, Mattia; Chiapparini, Luisa; Leone, Massimo

2018-01-01

Objective We tested the hypothesis of a defective functional connectivity between the posterior hypothalamus and diencephalic-mesencephalic regions in chronic cluster headache based on: a) clinical and neuro-endocrinological findings in cluster headache patients; b) neuroimaging findings during cluster headache attacks; c) neuroimaging findings in drug-refractory chronic cluster headache patients improved after successful deep brain stimulation. Methods Resting state functional magnetic resonance imaging, associated with a seed-based approach, was employed to investigate the functional connectivity of the posterior hypothalamus in chronic cluster headache patients (n = 17) compared to age and sex-matched healthy subjects (n = 16). Random-effect analyses were performed to study differences between patients and controls in ipsilateral and contralateral-to-the-pain posterior hypothalamus functional connectivity. Results Cluster headache patients showed an increased functional connectivity between the ipsilateral posterior hypothalamus and a number of diencephalic-mesencephalic structures, comprising ventral tegmental area, dorsal nuclei of raphe, and bilateral substantia nigra, sub-thalamic nucleus, and red nucleus ( p < 0.005 FDR-corrected vs . control group). No difference between patients and controls was found comparing the contralateral hypothalami. Conclusions The observed deranged functional connectivity between the posterior ipsilateral hypothalamus and diencephalic-mesencephalic regions in chronic cluster headache patients mainly involves structures that are part of (i.e. ventral tegmental area, substantia nigra) or modulate (dorsal nuclei of raphe, sub-thalamic nucleus) the midbrain dopaminergic systems. The midbrain dopaminergic systems could play a role in cluster headache pathophysiology and in particular in the chronicization process. Future studies are needed to better clarify if this finding is specific to cluster headache or if it represents an unspecific response to chronic pain.

Galaxy Population Properties in the Rich Clusters MS 0839.8+2938, MS 1224.7+2007, and MS 1231.3+1542

NASA Astrophysics Data System (ADS)

Hutchings, J. B.; Edwards, L.

2000-03-01

This paper discusses the galaxy populations of three rich clusters, with redshifts 0.19 (0839+29), 0.24 (1231+15), and 0.32 (1224+20), from the database of the CNOC1 consortium. The data consist of spectra of 52 cluster members for 0839+29, 30 members for 1224+15, and 82 members for 1231+15, and there are comparable numbers of field galaxy spectra. Cluster 0839+29 is compact with no strong radial gradients, and possibly dusty. Cluster 1224+20 is isolated in redshift and has low velocity dispersion around the cD galaxy and low 4000 Å break. Cluster 1231+15 is asymmetric, and we discuss the possibility that it may be a recent merger of two old clusters. We find few galaxies in 0839+29 and 1231+15 with ongoing or recently truncated star formation. Based on observations with the Canada-France-Hawaii-Telescope, which is operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

Case-control geographic clustering for residential histories accounting for risk factors and covariates.

PubMed

Jacquez, Geoffrey M; Meliker, Jaymie R; Avruskin, Gillian A; Goovaerts, Pierre; Kaufmann, Andy; Wilson, Mark L; Nriagu, Jerome

2006-08-03

Methods for analyzing space-time variation in risk in case-control studies typically ignore residential mobility. We develop an approach for analyzing case-control data for mobile individuals and apply it to study bladder cancer in 11 counties in southeastern Michigan. At this time data collection is incomplete and no inferences should be drawn - we analyze these data to demonstrate the novel methods. Global, local and focused clustering of residential histories for 219 cases and 437 controls is quantified using time-dependent nearest neighbor relationships. Business address histories for 268 industries that release known or suspected bladder cancer carcinogens are analyzed. A logistic model accounting for smoking, gender, age, race and education specifies the probability of being a case, and is incorporated into the cluster randomization procedures. Sensitivity of clustering to definition of the proximity metric is assessed for 1 to 75 k nearest neighbors. Global clustering is partly explained by the covariates but remains statistically significant at 12 of the 14 levels of k considered. After accounting for the covariates 26 Local clusters are found in Lapeer, Ingham, Oakland and Jackson counties, with the clusters in Ingham and Oakland counties appearing in 1950 and persisting to the present. Statistically significant focused clusters are found about the business address histories of 22 industries located in Oakland (19 clusters), Ingham (2) and Jackson (1) counties. Clusters in central and southeastern Oakland County appear in the 1930's and persist to the present day. These methods provide a systematic approach for evaluating a series of increasingly realistic alternative hypotheses regarding the sources of excess risk. So long as selection of cases and controls is population-based and not geographically biased, these tools can provide insights into geographic risk factors that were not specifically assessed in the case-control study design.

Delineating Scholarly Types of College and University Faculty Members

ERIC Educational Resources Information Center

Park, Toby J.; Braxton, John M.

2013-01-01

This study was conducted using cluster analysis as well as discriminant analysis to empirically identify types of faculty based on their patterns of performance of scholarship reflective of one or more of Boyer's four domains of scholarship. (Contains 5 tables and 1 figure.)

Exploring the Impacts of Social Networking Sites on Academic Relations in the University

ERIC Educational Resources Information Center

Rambe, Patient

2011-01-01

Social networking sites (SNS) affordances for persistent interaction, collective generation of knowledge, and formation of peer-based clusters for knowledge sharing render them useful for developing constructivist knowledge environments. However, notwithstanding their academic value, these environments are not necessarily insulated from the…

A lightweight universe?

PubMed Central

Bahcall, Neta A.; Fan, Xiaohui

1998-01-01

How much matter is there in the universe? Does the universe have the critical density needed to stop its expansion, or is the universe underweight and destined to expand forever? We show that several independent measures, especially those utilizing the largest bound systems known—clusters of galaxies—all indicate that the mass-density of the universe is insufficient to halt the expansion. A promising new method, the evolution of the number density of clusters with time, provides the most powerful indication so far that the universe has a subcritical density. We show that different techniques reveal a consistent picture of a lightweight universe with only ∼20–30% of the critical density. Thus, the universe may expand forever. PMID:9600898

Cluster Randomized Test-Negative Design (CR-TND) Trials: A Novel and Efficient Method to Assess the Efficacy of Community Level Dengue Interventions.

PubMed

Anders, Katherine L; Cutcher, Zoe; Kleinschmidt, Immo; Donnelly, Christl A; Ferguson, Neil M; Indriani, Citra; O'Neill, Scott L; Jewell, Nicholas P; Simmons, Cameron P

2018-05-07

Cluster randomized trials are the gold standard for assessing efficacy of community-level interventions, such as vector control strategies against dengue. We describe a novel cluster randomized trial methodology with a test-negative design, which offers advantages over traditional approaches. It utilizes outcome-based sampling of patients presenting with a syndrome consistent with the disease of interest, who are subsequently classified as test-positive cases or test-negative controls on the basis of diagnostic testing. We use simulations of a cluster trial to demonstrate validity of efficacy estimates under the test-negative approach. This demonstrates that, provided study arms are balanced for both test-negative and test-positive illness at baseline and that other test-negative design assumptions are met, the efficacy estimates closely match true efficacy. We also briefly discuss analytical considerations for an odds ratio-based effect estimate arising from clustered data, and outline potential approaches to analysis. We conclude that application of the test-negative design to certain cluster randomized trials could increase their efficiency and ease of implementation.

Inflammatory endotypes of chronic rhinosinusitis based on cluster analysis of biomarkers.

PubMed

Tomassen, Peter; Vandeplas, Griet; Van Zele, Thibaut; Cardell, Lars-Olaf; Arebro, Julia; Olze, Heidi; Förster-Ruhrmann, Ulrike; Kowalski, Marek L; Olszewska-Ziąber, Agnieszka; Holtappels, Gabriele; De Ruyck, Natalie; Wang, Xiangdong; Van Drunen, Cornelis; Mullol, Joaquim; Hellings, Peter; Hox, Valerie; Toskala, Elina; Scadding, Glenis; Lund, Valerie; Zhang, Luo; Fokkens, Wytske; Bachert, Claus

2016-05-01

Current phenotyping of chronic rhinosinusitis (CRS) into chronic rhinosinusitis with nasal polyps (CRSwNP) and chronic rhinosinusitis without nasal polyps (CRSsNP) might not adequately reflect the pathophysiologic diversity within patients with CRS. We sought to identify inflammatory endotypes of CRS. Therefore we aimed to cluster patients with CRS based solely on immune markers in a phenotype-free approach. Secondarily, we aimed to match clusters to phenotypes. In this multicenter case-control study patients with CRS and control subjects underwent surgery, and tissue was analyzed for IL-5, IFN-γ, IL-17A, TNF-α, IL-22, IL-1β, IL-6, IL-8, eosinophilic cationic protein, myeloperoxidase, TGF-β1, IgE, Staphylococcus aureus enterotoxin-specific IgE, and albumin. We used partition-based clustering. Clustering of 173 cases resulted in 10 clusters, of which 4 clusters with low or undetectable IL-5, eosinophilic cationic protein, IgE, and albumin concentrations, and 6 clusters with high concentrations of those markers. The group of IL-5-negative clusters, 3 clusters clinically resembled a predominant chronic rhinosinusitis without nasal polyps (CRSsNP) phenotype without increased asthma prevalence, and 1 cluster had a TH17 profile and had mixed CRSsNP/CRSwNP. The IL-5-positive clusters were divided into a group with moderate IL-5 concentrations, a mixed CRSsNP/CRSwNP and increased asthma phenotype, and a group with high IL-5 levels, an almost exclusive nasal polyp phenotype with strongly increased asthma prevalence. In the latter group, 2 clusters demonstrated the highest concentrations of IgE and asthma prevalence, with all samples expressing Staphylococcus aureus enterotoxin-specific IgE. Distinct CRS clusters with diverse inflammatory mechanisms largely correlated with phenotypes and further differentiated them and provided a more accurate description of the inflammatory mechanisms involved than phenotype information only. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Goal Profiles, Mental Toughness and its Influence on Performance Outcomes among Wushu Athletes

PubMed Central

Roy, Jolly

2007-01-01

This study examined the association between goal orientations and mental toughness and its influence on performance outcomes in competition. Wushu athletes (n = 40) competing in Intervarsity championships in Malaysia completed Task and Ego Orientations in Sport Questionnaire (TEOSQ) and Psychological Performance Inventory (PPI). Using cluster analysis techniques including hierarchical methods and the non-hierarchical method (k-means cluster) to examine goal profiles, a three cluster solution emerged viz. cluster 1 - high task and moderate ego (HT/ME), cluster 2 - moderate task and low ego (MT/LE) and, cluster 3 - moderate task and moderate ego (MT/ME). Analysis of the fundamental areas of mental toughness based on goal profiles revealed that athletes in cluster 1 scored significantly higher on negative energy control than athletes in cluster 2. Further, athletes in cluster 1 also scored significantly higher on positive energy control than athletes in cluster 3. Chi-square (χ2) test revealed no significant differences among athletes with different goal profiles on performance outcomes in the competition. However, significant differences were observed between athletes (medallist and non medallist) in self- confidence (p = 0.001) and negative energy control (p = 0.042). Medallist’s scored significantly higher on self-confidence (mean = 21.82 ± 2.72) and negative energy control (mean = 19.59 ± 2.32) than the non-medallists (self confidence-mean = 18.76 ± 2.49; negative energy control mean = 18.14 ± 1.91). Key points Mental toughness can be influenced by certain goal profile combination. Athletes with successful outcomes in performance (medallist) displayed greater mental toughness. PMID:24198700

Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

NASA Astrophysics Data System (ADS)

Podestà, Alessandro; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo

2015-12-01

Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO2) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevant interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility.

Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podestà, Alessandro, E-mail: alessandro.podesta@mi.infn.it, E-mail: pmilani@mi.infn.it; Borghi, Francesca; Indrieri, Marco

Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO{sub 2}) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevantmore » interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility.« less

The Luminosity Function of Star Clusters in 20 Star-forming Galaxies Based on Hubble Legacy Archive Photometry

NASA Astrophysics Data System (ADS)

Whitmore, Bradley C.; Chandar, Rupali; Bowers, Ariel S.; Larsen, Soeren; Lindsay, Kevin; Ansari, Asna; Evans, Jessica

2014-04-01

Luminosity functions (LFs) have been determined for star cluster populations in 20 nearby (4-30 Mpc), star-forming galaxies based on Advanced Camera for Surveys source lists generated by the Hubble Legacy Archive (HLA). These cluster catalogs provide one of the largest sets of uniform, automatically generated cluster candidates available in the literature at present. Comparisons are made with other recently generated cluster catalogs demonstrating that the HLA-generated catalogs are of similar quality, but in general do not go as deep. A typical cluster LF can be approximated by a power law, dN/dLvpropL α, with an average value for α of -2.37 and rms scatter = 0.18 when using the F814W ("I") band. A comparison of fitting results based on methods that use binned and unbinned data shows good agreement, although there may be a systematic tendency for the unbinned (maximum likelihood) method to give slightly more negative values of α for galaxies with steeper LFs. We find that galaxies with high rates of star formation (or equivalently, with the brightest or largest numbers of clusters) have a slight tendency to have shallower values of α. In particular, the Antennae galaxy (NGC 4038/39), a merging system with a relatively high star formation rate (SFR), has the second flattest LF in the sample. A tentative correlation may also be present between Hubble type and values of α, in the sense that later type galaxies (i.e., Sd and Sm) appear to have flatter LFs. Hence, while there do appear to be some weak correlations, the relative similarity in the values of α for a large number of star-forming galaxies suggests that, to first order, the LFs are fairly universal. We examine the bright end of the LFs and find evidence for a downturn, although it only pertains to about 1% of the clusters. Our uniform database results in a small scatter (≈0.4 to 0.5 mag) in the correlation between the magnitude of the brightest cluster (M brightest) and log of the number of clusters brighter than MI = -9 (log N). We also examine the magnitude of the brightest cluster versus log SFR for a sample including both dwarf galaxies and ULIRGs. This shows that the correlation extends over roughly six orders of magnitude but with scatter that is larger than for our spiral sample, probably because of the high levels of extinction in many of the LIRGs. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Also based on data obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA), and the Canadian Astronomy Data Centre (CADC/NRC/CSA). Support for Program number 11781 was provided by NASA through a grant from the Space Telescope Science Institute.

Innovative public–private partnership to target subsidised antimalarials: a study protocol for a cluster randomised controlled trial to evaluate a community intervention in Western Kenya

PubMed Central

Laktabai, Jeremiah; Lesser, Adriane; Platt, Alyssa; Maffioli, Elisa; Mohanan, Manoj; Menya, Diana; Prudhomme O'Meara, Wendy; Turner, Elizabeth L

2017-01-01

Introduction There are concerns of inappropriate use of subsidised antimalarials due to the large number of fevers treated in the informal sector with minimal access to diagnostic testing. Targeting antimalarial subsidies to confirmed malaria cases can lead to appropriate, effective therapy. There is evidence that community health volunteers (CHVs) can be trained to safely and correctly use rapid diagnostic tests (RDTs). This study seeks to evaluate the public health impact of targeted antimalarial subsidies delivered through a partnership between CHVs and the private retail sector. Methods and analysis We are conducting a stratified cluster-randomised controlled trial in Western Kenya where 32 community units were randomly assigned to the intervention or control (usual care) arm. In the intervention arm, CHVs offer free RDT testing to febrile individuals and, conditional on a positive test result, a voucher to purchase a WHO-qualified artemisinin combination therapy (ACT) at a reduced fixed price in the retail sector. Study outcomes in individuals with a febrile illness in the previous 4 weeks will be ascertained through population-based cross-sectional household surveys at four time points: baseline, 6, 12 and 18 months postbaseline. The primary outcome is the proportion of fevers that receives a malaria test from any source (CHV or health facility). The main secondary outcome is the proportion of ACTs used by people with a malaria-positive test. Other secondary outcomes include: the proportion of ACTs used by people without a test and adherence to test results. Ethics and dissemination The protocol has been approved by the National Institutes of Health, the Moi University School of Medicine Institutional Research and Ethics Committee and the Duke University Medical Center Institutional Review Board. Findings will be reported on clinicalstrials.gov, in peer-reviewed publications and through stakeholder meetings including those with the Kenyan Ministry of Health. Trial registration number Pre-results, NCT02461628. PMID:28320794

Automatic pole-like object modeling via 3D part-based analysis of point cloud

NASA Astrophysics Data System (ADS)

He, Liu; Yang, Haoxiang; Huang, Yuchun

2016-10-01

Pole-like objects, including trees, lampposts and traffic signs, are indispensable part of urban infrastructure. With the advance of vehicle-based laser scanning (VLS), massive point cloud of roadside urban areas becomes applied in 3D digital city modeling. Based on the property that different pole-like objects have various canopy parts and similar trunk parts, this paper proposed the 3D part-based shape analysis to robustly extract, identify and model the pole-like objects. The proposed method includes: 3D clustering and recognition of trunks, voxel growing and part-based 3D modeling. After preprocessing, the trunk center is identified as the point that has local density peak and the largest minimum inter-cluster distance. Starting from the trunk centers, the remaining points are iteratively clustered to the same centers of their nearest point with higher density. To eliminate the noisy points, cluster border is refined by trimming boundary outliers. Then, candidate trunks are extracted based on the clustering results in three orthogonal planes by shape analysis. Voxel growing obtains the completed pole-like objects regardless of overlaying. Finally, entire trunk, branch and crown part are analyzed to obtain seven feature parameters. These parameters are utilized to model three parts respectively and get signal part-assembled 3D model. The proposed method is tested using the VLS-based point cloud of Wuhan University, China. The point cloud includes many kinds of trees, lampposts and other pole-like posters under different occlusions and overlaying. Experimental results show that the proposed method can extract the exact attributes and model the roadside pole-like objects efficiently.

Cluster synchronization transmission of different external signals in discrete uncertain network

NASA Astrophysics Data System (ADS)

Li, Chengren; Lü, Ling; Chen, Liansong; Hong, Yixuan; Zhou, Shuang; Yang, Yiming

2018-07-01

We research cluster synchronization transmissions of different external signals in discrete uncertain network. Based on the Lyapunov theorem, the network controller and the identification law of uncertain adjustment parameter are designed, and they are efficiently used to achieve the cluster synchronization and the identification of uncertain adjustment parameter. In our technical scheme, the network nodes in each cluster and the transmitted external signal can be different, and they allow the presence of uncertain parameters in the network. Especially, we are free to choose the clustering topologies, the cluster number and the node number in each cluster.

A Very Hot, High Redshift Cluster of Galaxies: More Trouble for Omega(0) = 1

NASA Technical Reports Server (NTRS)

Donahue, Megan; Voit, G. Mark; Gioia, Isabella; Luppino, Gerry; Hughes, John P.; Stocke, John T.

1998-01-01

We have observed the most distant (= 0.829) cluster of galaxies in the Einstein Extended Medium Sensitivity Survey (EMSS), with the ASCA and ROSAT satellites. We find an X-ray temperature of 12.3 (sup +3.1) (sub -2.2)keV for this cluster, and the ROSAT map reveals significant substructure. The high temperature of MS1054-0321 is consistent with both its approximate velocity dispersion, based on the redshifts of 12 cluster members we have obtained at the Keck and the Canada-France-Hawaii telescopes, and with its weak lensing signature. The X-ray temperature of this cluster implies a virial mass approx. 7.4 x 10 (sup 14) h (sup -1) M (circle dot), if the mean matter density in the universe equals the critical value (OMEGA (sub 0) = 1), or larger if OMEGA (sub 0) is less than 1. Finding such a hot, massive cluster in the EMSS is extremely improbable if clusters grew from Gaussian perturbations in an OMEGA (sub 0) = 1 universe. Combining the assumptions that OMEGA (sub 0) = 1 and that the initial perturbations were Gaussian with the observed X-ray temperature function at low redshift, we show that this probability of this cluster occurring in the volume sampled by the EMSS is less than a few times 10 (sup -5). Nor is MS1054-0321 the only hot cluster at high redshift; the only two other z greater than 0.5 EMSS clusters already observed with ASCA also have temperatures exceeding 8 keV. Assuming again that the initial perturbations were Gaussian and OMEGA (sub 0) = 1, we find that each one is improbable at the less than 10 (sup -2) level. These observations, along with the fact that these luminosities and temperatures of the high-z clusters all agree with the low-z L (sub X) - T (sub X) relation, argue strongly that OMEGA (sub 0) less than 1. Otherwise, the initial perturbations must be non-Gaussian, if these clusters' temperatures do indeed reflect their gravitational potentials.

A Cluster-Randomized Trial of Restorative Practices: An Illustration to Spur High-Quality Research and Evaluation

ERIC Educational Resources Information Center

Acosta, Joie D.; Chinman, Matthew; Ebener, Patricia; Phillips, Andrea; Xenakis, Lea; Malone, Patrick S.

2016-01-01

Restorative practices in schools lack rigorous evaluation studies. As an example of rigorous school-based research, this article describes the first randomized control trial of restorative practices to date, the Study of Restorative Practices. It is a 5-year, cluster-randomized controlled trial (RCT) of the Restorative Practices Intervention (RPI)…

Cancer detection based on Raman spectra super-paramagnetic clustering

NASA Astrophysics Data System (ADS)

González-Solís, José Luis; Guizar-Ruiz, Juan Ignacio; Martínez-Espinosa, Juan Carlos; Martínez-Zerega, Brenda Esmeralda; Juárez-López, Héctor Alfonso; Vargas-Rodríguez, Héctor; Gallegos-Infante, Luis Armando; González-Silva, Ricardo Armando; Espinoza-Padilla, Pedro Basilio; Palomares-Anda, Pascual

2016-08-01

The clustering of Raman spectra of serum sample is analyzed using the super-paramagnetic clustering technique based in the Potts spin model. We investigated the clustering of biochemical networks by using Raman data that define edge lengths in the network, and where the interactions are functions of the Raman spectra's individual band intensities. For this study, we used two groups of 58 and 102 control Raman spectra and the intensities of 160, 150 and 42 Raman spectra of serum samples from breast and cervical cancer and leukemia patients, respectively. The spectra were collected from patients from different hospitals from Mexico. By using super-paramagnetic clustering technique, we identified the most natural and compact clusters allowing us to discriminate the control and cancer patients. A special interest was the leukemia case where its nearly hierarchical observed structure allowed the identification of the patients's leukemia type. The goal of this study is to apply a model of statistical physics, as the super-paramagnetic, to find these natural clusters that allow us to design a cancer detection method. To the best of our knowledge, this is the first report of preliminary results evaluating the usefulness of super-paramagnetic clustering in the discipline of spectroscopy where it is used for classification of spectra.

Confronting models of star formation quenching in galaxy clusters with archival Spitzer data

NASA Astrophysics Data System (ADS)

Rudnick, Gregory

Large scale structures in the universe form hierarchically: small structures merge to form larger ones. Over the same epoch where these structures experience significant growth, the fraction of star forming galaxies within them decreases, and at a faster rate than for field galaxies. It is now widely accepted that there must be physical processes at work in these dense environments to actively quench star formation. However, despite no shortage of candidate mechanisms, sophisticated cosmological simulations still cannot reproduce the star formation rate distributions within dense environments, such as galaxy clusters. Insufficient observational constraints are a primary obstacle to further progress. In particular, the interpretation of observations of nearby clusters relies on untested assumptions about the properties of galaxies before they entered the dense cluster environment at higher redshifts. Clearly, direct constraints on these properties are required. Our group has assembled two data sets designed to address these concerns. The first focuses on an intermediate wide-field cluster sample and the second focuses on a well-matched low-redshift cluster sample. We will use these samples, along with sophisticated models of hierarchical galaxy formation, to meet the following objectives: 1. Directly measure the SFR distribution of the progenitors of present-day cluster galaxies. We will use ground-based spectroscopy to identify cluster members within four virial radii of eight intermediate-redshift clusters. We will couple this with archival Spitzer/MIPS data to measure the SFRs of galaxies out to the cluster outskirts. 2. Measure the SFR distribution of the present-day cluster galaxies using Spitzer and WISE. Robust N-body simulations tell us statistically which galaxies at intermediate redshifts will have entered the cluster virial radius by the current epoch. By combining our wide-field coverage at high redshift with our local cluster sample, we will determine the evolution in cluster galaxy SFRs over 6 billion years making minimal assumptions about the infalling galaxy population. 3. Provide a rigorous test of the quenching processes embedded in the theoretical models. We will create observed realizations of the theoretical models by subjecting them to our observational selection. This will enable a fair comparison between the models and the data, which will provide a valuable test of current theoretical implementations of quenching processes. We will also modify the quenching prescriptions in the models to determine the parameters required to reproduce the observations. The proposed research is novel for several reasons. 1) We have wide-field Spitzer/MIPS data that allows us to robustly measure SFRs in our distant cluster galaxies. WISE data on local clusters will provide us with analogous measurements in the nearby Universe. 2) Our significant investment in ancillary spectroscopy allows us to identify infalling galaxies that will eventually join the central regions of the cluster z=0. 3) Our intermediate redshift cluster sample was chosen to have characteristics expected for the progenitors of a large fraction of the known clusters at z=0. 4) We will take advantage of our own cosmological simulations of structure growth to interpret our data. 5) We have optical photometry over the full infall region, allowing us to control for stellar masses and to distinguish passive from dusty star-forming galaxies. We will learn which, if any, of the quenching prescriptions currently employed in semi-analytic models correctly reproduces the observed characteristics of the galaxies that will become cluster galaxies at z=0. We will pinpoint the cluster-centric radii over which quenching takes place between. We will determine the timescale (as a function of stellar mass) over which it must take place. This program will cement the legacy of Spitzer and WISE as tools for studying galaxy formation in clusters.

Surfactant-controlled polymerization of semiconductor clusters to quantum dots through competing step-growth and living chain-growth mechanisms.

PubMed

Evans, Christopher M; Love, Alyssa M; Weiss, Emily A

2012-10-17

This article reports control of the competition between step-growth and living chain-growth polymerization mechanisms in the formation of cadmium chalcogenide colloidal quantum dots (QDs) from CdSe(S) clusters by varying the concentration of anionic surfactant in the synthetic reaction mixture. The growth of the particles proceeds by step-addition from initially nucleated clusters in the absence of excess phosphinic or carboxylic acids, which adsorb as their anionic conjugate bases, and proceeds indirectly by dissolution of clusters, and subsequent chain-addition of monomers to stable clusters (Ostwald ripening) in the presence of excess phosphinic or carboxylic acid. Fusion of clusters by step-growth polymerization is an explanation for the consistent observation of so-called "magic-sized" clusters in QD growth reactions. Living chain-addition (chain addition with no explicit termination step) produces QDs over a larger range of sizes with better size dispersity than step-addition. Tuning the molar ratio of surfactant to Se(2-)(S(2-)), the limiting ionic reagent, within the living chain-addition polymerization allows for stoichiometric control of QD radius without relying on reaction time.

A clustering-based graph Laplacian framework for value function approximation in reinforcement learning.

PubMed

Xu, Xin; Huang, Zhenhua; Graves, Daniel; Pedrycz, Witold

2014-12-01

In order to deal with the sequential decision problems with large or continuous state spaces, feature representation and function approximation have been a major research topic in reinforcement learning (RL). In this paper, a clustering-based graph Laplacian framework is presented for feature representation and value function approximation (VFA) in RL. By making use of clustering-based techniques, that is, K-means clustering or fuzzy C-means clustering, a graph Laplacian is constructed by subsampling in Markov decision processes (MDPs) with continuous state spaces. The basis functions for VFA can be automatically generated from spectral analysis of the graph Laplacian. The clustering-based graph Laplacian is integrated with a class of approximation policy iteration algorithms called representation policy iteration (RPI) for RL in MDPs with continuous state spaces. Simulation and experimental results show that, compared with previous RPI methods, the proposed approach needs fewer sample points to compute an efficient set of basis functions and the learning control performance can be improved for a variety of parameter settings.

Modelling conflicts with cluster dynamics in networks

NASA Astrophysics Data System (ADS)

Tadić, Bosiljka; Rodgers, G. J.

2010-12-01

We introduce cluster dynamical models of conflicts in which only the largest cluster can be involved in an action. This mimics the situations in which an attack is planned by a central body, and the largest attack force is used. We study the model in its annealed random graph version, on a fixed network, and on a network evolving through the actions. The sizes of actions are distributed with a power-law tail, however, the exponent is non-universal and depends on the frequency of actions and sparseness of the available connections between units. Allowing the network reconstruction over time in a self-organized manner, e.g., by adding the links based on previous liaisons between units, we find that the power-law exponent depends on the evolution time of the network. Its lower limit is given by the universal value 5/2, derived analytically for the case of random fragmentation processes. In the temporal patterns behind the size of actions we find long-range correlations in the time series of the number of clusters and the non-trivial distribution of time that a unit waits between two actions. In the case of an evolving network the distribution develops a power-law tail, indicating that through repeated actions, the system develops an internal structure with a hierarchy of units.

DISTANT CLUSTER OF GALAXIES [left

NASA Technical Reports Server (NTRS)

2002-01-01

One of the deepest images to date of the universe, taken with NASA's Hubble Space Telescope (HST), reveals thousands of faint galaxies at the detection limit of present day telescopes. Peering across a large volume of the observable cosmos, Hubble resolves thousands of galaxies from five to twelve billion light-years away. The light from these remote objects has taken billions of years to cross the expanding universe, making these distant galaxies fossil evidence' of events that happened when the universe was one-third its present age. A fraction of the galaxies in this image belong to a cluster located nine billion light-years away. Though the field of view (at the cluster's distance) is only two million light-years across, it contains a multitude of fragmentary objects. (By comparison, the two million light-years between our Milky Way galaxy and its nearest large companion galaxy, in the constellation Andromeda, is essentially empty space!) Very few of the cluster's members are recognizable as normal spiral galaxies (like our Milky Way), although some elongated members might be edge-on disks. Among this zoo of odd galaxies are ``tadpole-like'' objects, disturbed and apparently merging systems dubbed 'train-wrecks,' and a multitude of faint, tiny shards and fragments, dwarf galaxies or possibly an unknown population of objects. However, the cluster also contains red galaxies that resemble mature examples of today's elliptical galaxies. Their red color comes from older stars that must have formed shortly after the Big Bang. The image is the full field view of the Wide Field and Planetary Camera-2. The picture was taken in intervals between May 11 and June 15, 1994 and required an 18-hour long exposure, over 32 orbits of HST, to reveal objects down to 29th magnitude. [bottom right] A close up view of the peculiar radio galaxy 3C324 used to locate the cluster. The galaxy is nine billion light-years away as measured by its spectral redshift (z=1.2), and located in the constellation Serpens. Based on the colors and the statistical distribution of the galaxies in 3C 324's vicinity, astronomers conclude a remote cluster is at the same distance as a radio galaxy. [center right] This pair of elliptical galaxies, seen together with a few fainter companions, is remarkably similar in shape, light distribution, and color to their present day descendants. This Hubble image provides evidence that ellipticals formed remarkably early in the universe. [top right] Some of the objects in this compact tangled group resemble today's spiral galaxies. However, they have irregular shapes and appear disrupted and asymmetric. This might be due to a high frequency of galaxy collisions and close encounters in the early universe. Credit: Mark Dickinson (STScI) and NASA

Personalising care of adults with asthma from Asia: a modified e-Dephi consensus study to inform management tailored to attitude and control profiles.

PubMed

Chisholm, Alison; Price, David B; Pinnock, Hilary; Lee, Tan Tze; Roa, Camilo; Cho, Sang-Heon; David-Wang, Aileen; Wong, Gary; van der Molen, Thys; Ryan, Dermot; Castillo-Carandang, Nina; Yong, Yee Vern

2017-01-05

REALISE Asia-an online questionnaire-based study of Asian asthma patients-identified five patient clusters defined in terms of their control status and attitude towards their asthma (categorised as: 'Well-adjusted and at least partly controlled'; 'In denial about symptoms'; 'Tolerating with poor control'; 'Adrift and poorly controlled'; 'Worried with multiple symptoms'). We developed consensus recommendations for tailoring management of these attitudinal-control clusters. An expert panel undertook a three-round electronic Delphi (e-Delphi): Round 1: panellists received descriptions of the attitudinal-control clusters and provided free text recommendations for their assessment and management. Round 2: panellists prioritised Round 1 recommendations and met (or joined a teleconference) to consolidate the recommendations. Round 3: panellists voted and prioritised the remaining recommendations. Consensus was defined as Round 3 recommendations endorsed by >50% of panellists. Highest priority recommendations were those receiving the highest score. The multidisciplinary panellists (9 clinicians, 1 pharmacist and 1 health social scientist; 7 from Asia) identified consensus recommendations for all clusters. Recommended pharmacological (e.g., step-up/down; self-management; simplified regimen) and non-pharmacological approaches (e.g., trigger management, education, social support; inhaler technique) varied substantially according to each cluster's attitude to asthma and associated psychosocial drivers of behaviour. The attitudinal-control clusters defined by REALISE Asia resonated with the international panel. Consensus was reached on appropriate tailored management approaches for all clusters. Summarised and incorporated into a structured management pathway, these recommendations could facilitate personalised care. Generalisability of these patient clusters should be assessed in other socio-economic, cultural and literacy groups and nationalities in Asia.

Cluster randomised crossover trials with binary data and unbalanced cluster sizes: application to studies of near-universal interventions in intensive care.

PubMed

Forbes, Andrew B; Akram, Muhammad; Pilcher, David; Cooper, Jamie; Bellomo, Rinaldo

2015-02-01

Cluster randomised crossover trials have been utilised in recent years in the health and social sciences. Methods for analysis have been proposed; however, for binary outcomes, these have received little assessment of their appropriateness. In addition, methods for determination of sample size are currently limited to balanced cluster sizes both between clusters and between periods within clusters. This article aims to extend this work to unbalanced situations and to evaluate the properties of a variety of methods for analysis of binary data, with a particular focus on the setting of potential trials of near-universal interventions in intensive care to reduce in-hospital mortality. We derive a formula for sample size estimation for unbalanced cluster sizes, and apply it to the intensive care setting to demonstrate the utility of the cluster crossover design. We conduct a numerical simulation of the design in the intensive care setting and for more general configurations, and we assess the performance of three cluster summary estimators and an individual-data estimator based on binomial-identity-link regression. For settings similar to the intensive care scenario involving large cluster sizes and small intra-cluster correlations, the sample size formulae developed and analysis methods investigated are found to be appropriate, with the unweighted cluster summary method performing well relative to the more optimal but more complex inverse-variance weighted method. More generally, we find that the unweighted and cluster-size-weighted summary methods perform well, with the relative efficiency of each largely determined systematically from the study design parameters. Performance of individual-data regression is adequate with small cluster sizes but becomes inefficient for large, unbalanced cluster sizes. When outcome prevalences are 6% or less and the within-cluster-within-period correlation is 0.05 or larger, all methods display sub-nominal confidence interval coverage, with the less prevalent the outcome the worse the coverage. As with all simulation studies, conclusions are limited to the configurations studied. We confined attention to detecting intervention effects on an absolute risk scale using marginal models and did not explore properties of binary random effects models. Cluster crossover designs with binary outcomes can be analysed using simple cluster summary methods, and sample size in unbalanced cluster size settings can be determined using relatively straightforward formulae. However, caution needs to be applied in situations with low prevalence outcomes and moderate to high intra-cluster correlations. © The Author(s) 2014.

Stabilization of sulfuric acid dimers by ammonia, methylamine, dimethylamine, and trimethylamine

NASA Astrophysics Data System (ADS)

Jen, Coty N.; McMurry, Peter H.; Hanson, David R.

2014-06-01

This study experimentally explores how ammonia (NH3), methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) affect the chemical formation mechanisms of electrically neutral clusters that contain two sulfuric acid molecules (dimers). Dimers may also contain undetectable compounds, such as water or bases, that evaporate upon ionization and sampling. Measurements were conducted using a glass flow reactor which contained a steady flow of humidified nitrogen with sulfuric acid concentrations of 107 to 109 cm-3. A known molar flow rate of a basic gas was injected into the flow reactor. The University of Minnesota Cluster Chemical Ionization Mass Spectrometer was used to measure the resulting sulfuric acid vapor and cluster concentrations. It was found that, for a given concentration of sulfuric acid vapor, the dimer concentration increases with increasing concentration of the basic gas, eventually reaching a plateau. The base concentrations at which the dimer concentrations saturate suggest NH3 < MA < TMA ≲ DMA in forming stabilized sulfuric acid dimers. Two heuristic models for cluster formation by acid-base reactions are developed to interpret the data. The models provide ranges of evaporation rate constants that are consistent with observations and leads to an analytic expression for nucleation rates that is consistent with atmospheric observations.

Cluster headache and the hypocretin receptor 2 reconsidered: a genetic association study and meta-analysis.

PubMed

Weller, Claudia M; Wilbrink, Leopoldine A; Houwing-Duistermaat, Jeanine J; Koelewijn, Stephany C; Vijfhuizen, Lisanne S; Haan, Joost; Ferrari, Michel D; Terwindt, Gisela M; van den Maagdenberg, Arn M J M; de Vries, Boukje

2015-08-01

Cluster headache is a severe neurological disorder with a complex genetic background. A missense single nucleotide polymorphism (rs2653349; p.Ile308Val) in the HCRTR2 gene that encodes the hypocretin receptor 2 is the only genetic factor that is reported to be associated with cluster headache in different studies. However, as there are conflicting results between studies, we re-evaluated its role in cluster headache. We performed a genetic association analysis for rs2653349 in our large Leiden University Cluster headache Analysis (LUCA) program study population. Systematic selection of the literature yielded three additional studies comprising five study populations, which were included in our meta-analysis. Data were extracted according to predefined criteria. A total of 575 cluster headache patients from our LUCA study and 874 controls were genotyped for HCRTR2 SNP rs2653349 but no significant association with cluster headache was found (odds ratio 0.91 (95% confidence intervals 0.75-1.10), p = 0.319). In contrast, the meta-analysis that included in total 1167 cluster headache cases and 1618 controls from the six study populations, which were part of four different studies, showed association of the single nucleotide polymorphism with cluster headache (random effect odds ratio 0.69 (95% confidence intervals 0.53-0.90), p = 0.006). The association became weaker, as the odds ratio increased to 0.80, when the meta-analysis was repeated without the initial single South European study with the largest effect size. Although we did not find evidence for association of rs2653349 in our LUCA study, which is the largest investigated study population thus far, our meta-analysis provides genetic evidence for a role of HCRTR2 in cluster headache. Regardless, we feel that the association should be interpreted with caution as meta-analyses with individual populations that have limited power have diminished validity. © International Headache Society 2014.

A Typology of Students Based on Academic Entitlement

ERIC Educational Resources Information Center

Luckett, Michael; Trocchia, Philip J.; Noel, Noel Mark; Marlin, Dan

2017-01-01

Two hundred ninety-three university business students were surveyed using an academic entitlement (AE) scale updated to include new technologies. Using factor analysis, three components of AE were identified: grade entitlement, behavioral entitlement, and service entitlement. A k-means clustering procedure was then applied to identify four groups…

Universal dynamical properties preclude standard clustering in a large class of biochemical data.

PubMed

Gomez, Florian; Stoop, Ralph L; Stoop, Ruedi

2014-09-01

Clustering of chemical and biochemical data based on observed features is a central cognitive step in the analysis of chemical substances, in particular in combinatorial chemistry, or of complex biochemical reaction networks. Often, for reasons unknown to the researcher, this step produces disappointing results. Once the sources of the problem are known, improved clustering methods might revitalize the statistical approach of compound and reaction search and analysis. Here, we present a generic mechanism that may be at the origin of many clustering difficulties. The variety of dynamical behaviors that can be exhibited by complex biochemical reactions on variation of the system parameters are fundamental system fingerprints. In parameter space, shrimp-like or swallow-tail structures separate parameter sets that lead to stable periodic dynamical behavior from those leading to irregular behavior. We work out the genericity of this phenomenon and demonstrate novel examples for their occurrence in realistic models of biophysics. Although we elucidate the phenomenon by considering the emergence of periodicity in dependence on system parameters in a low-dimensional parameter space, the conclusions from our simple setting are shown to continue to be valid for features in a higher-dimensional feature space, as long as the feature-generating mechanism is not too extreme and the dimension of this space is not too high compared with the amount of available data. For online versions of super-paramagnetic clustering see http://stoop.ini.uzh.ch/research/clustering. Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Lens models under the microscope: comparison of Hubble Frontier Field cluster magnification maps

NASA Astrophysics Data System (ADS)

Priewe, Jett; Williams, Liliya L. R.; Liesenborgs, Jori; Coe, Dan; Rodney, Steven A.

2017-02-01

Using the power of gravitational lensing magnification by massive galaxy clusters, the Hubble Frontier Fields provide deep views of six patches of the high-redshift Universe. The combination of deep Hubble imaging and exceptional lensing strength has revealed the greatest numbers of multiply-imaged galaxies available to constrain models of cluster mass distributions. However, even with O(100) images per cluster, the uncertainties associated with the reconstructions are not negligible. The goal of this paper is to show the diversity of model magnification predictions. We examine seven and nine mass models of Abell 2744 and MACS J0416, respectively, submitted to the Mikulski Archive for Space Telescopes for public distribution in 2015 September. The dispersion between model predictions increases from 30 per cent at common low magnifications (μ ˜ 2) to 70 per cent at rare high magnifications (μ ˜ 40). MACS J0416 exhibits smaller dispersions than Abell 2744 for 2 < μ < 10. We show that magnification maps based on different lens inversion techniques typically differ from each other by more than their quoted statistical errors. This suggests that some models underestimate the true uncertainties, which are primarily due to various lensing degeneracies. Though the exact mass sheet degeneracy is broken, its generalized counterpart is not broken at least in Abell 2744. Other local degeneracies are also present in both clusters. Our comparison of models is complementary to the comparison of reconstructions of known synthetic mass distributions. By focusing on observed clusters, we can identify those that are best constrained, and therefore provide the clearest view of the distant Universe.

Map-based trigonometric parallaxes of open clusters: Coma

NASA Technical Reports Server (NTRS)

Gatewood, George

1995-01-01

This is the fourth study in a series to determine the direct trigonometric parallaxes of four of the nearest open star clusters, the Hyades, the Pleiades, the Praesepe, and the nearby cluster in Coma (Gatewood et al. 1990; Gatewood et al. 1992); Gatewood & Kiewiet de Jonge 1994). The results for the open star cluster in Coma are compared with those of the other three clusters, and the members are found to be significantly subluminous. The trigonometric parallax of the cluster is estimated from that of three members studied with the Multichannel Astrometric Photometer (MAP) at the Thaw Refractor of the University of Pittsburgh's Allegheny Observatory. The weighted mean parallax of the cluster is +13.53 +/- 0.54 mass (0.00054 min), corresponding to a distance modulus of 4.34 +/- 0.09 mag. The U-B excess of the Coma cluster members may be used to adjust the observed absolute magnitudes and the B-V measurements as suggested by Sandage & Eggen (1959). The agreement obtained in this manner suggests that, like subdwarf stars, the stars of the Coma cluster appear subluminous because of line blanketing. One of the three members observed in this study was recognized as a member by its parallax and is the faintest known member of the cluster.

Map-based trigonometric parallaxes of open clusters: Coma

NASA Astrophysics Data System (ADS)

Gatewood, George

1995-06-01

This is the fourth study in a series to determine the direct trigonometric parallaxes of four of the nearest open star clusters, the Hyades, the Pleiades, the Praesepe, and the nearby cluster in Coma (Gatewood et al. 1990; Gatewood et al. 1992); Gatewood & Kiewiet de Jonge 1994). The results for the open star cluster in Coma are compared with those of the other three clusters, and the members are found to be significantly subluminous. The trigonometric parallax of the cluster is estimated from that of three members studied with the Multichannel Astrometric Photometer (MAP) at the Thaw Refractor of the University of Pittsburgh's Allegheny Observatory. The weighted mean parallax of the cluster is +13.53 +/- 0.54 mass (0.00054 min), corresponding to a distance modulus of 4.34 +/- 0.09 mag. The U-B excess of the Coma cluster members may be used to adjust the observed absolute magnitudes and the B-V measurements as suggested by Sandage & Eggen (1959). The agreement obtained in this manner suggests that, like subdwarf stars, the stars of the Coma cluster appear subluminous because of line blanketing. One of the three members observed in this study was recognized as a member by its parallax and is the faintest known member of the cluster.

Spitzer Clusters

NASA Astrophysics Data System (ADS)

Krick, Kessica

This proposal is a specific response to the strategic goal of NASA's research program to "discover how the universe works and explore how the universe evolved into its present form." Towards this goal, we propose to mine the Spitzer archive for all observations of galaxy groups and clusters for the purpose of studying galaxy evolution in clusters, contamination rates for Sunyaev Zeldovich cluster surveys, and to provide a database of Spitzer observed clusters to the broader community. Funding from this proposal will go towards two years of support for a Postdoc to do this work. After searching the Spitzer Heritage Archive, we have found 194 unique galaxy groups and clusters that have data from both the Infrared array camera (IRAC; Fazio et al. 2004) at 3.6 - 8 microns and the multiband imaging photometer for Spitzer (MIPS; Rieke et al. 2004) at 24microns. This large sample will add value beyond the individual datasets because it will be a larger sample of IR clusters than ever before and will have sufficient diversity in mass, redshift, and dynamical state to allow us to differentiate amongst the effects of these cluster properties. An infrared sample is important because it is unaffected by dust extinction while at the same time is an excellent measure of both stellar mass (IRAC wavelengths) and star formation rate (MIPS wavelengths). Additionally, IRAC can be used to differentiate star forming galaxies (SFG) from active galactic nuclei (AGN), due to their different spectral shapes in this wavelength regime. Specifically, we intend to identify SFG and AGN in galaxy groups and clusters. Groups and clusters differ from the field because the galaxy densities are higher, there is a large potential well due mainly to the mass of the dark matter, and there is hot X-ray gas (the intracluster medium; ICM). We will examine the impact of these differences in environment on galaxy formation by comparing cluster properties of AGN and SFG to those in the field. Also, we will examine the effect that evolutions of cluster redshift and dynamical state have on SFG and AGN in groups and clusters. In addition to environment, we will study the timescales of chemical enrichment of the ICM, using the SFG and AGN as tracers of processes that can transport metals outside of galaxies. Cosmological parameters can be measured based on observing galaxy clusters as signposts of the growth of structure in the universe. The best way to select a redshift independent sample is to use the SZ effect with mm observations to detect a shift in the cosmic microwave background spectrum as those photons scatter off hot gas in clusters. However, such mm observations are contaminated by the emission of SFG and AGN. We intend to characterize the magnitude of this effect on SZ surveys by understanding the frequency, radial distribution, and redshift distribution of these galaxies in clusters. Lastly, a compiled cluster catalog of all Spitzer observed clusters would be useful to the broader astronomical community. We plan to incorporate ancillary multi-wavelength data, where available, and to both publish our catalog in journals, and work with NED to make the catalog easily accessible in an efficient manner by the community.

Slooh Takes Observing into the Classroom

NASA Astrophysics Data System (ADS)

Godfrey, Paige

2018-01-01

For many students, studying space is limited to simulations and a vivid imagination. Slooh is providing a new education tool that gives students an authentic experience, mimicking the practices of professional astronomers by bringing real-time astronomical observing to the classroom. Teachers and students have robotic control of Slooh’s global network of ground-based telescopes located at the Institute of Astrophysics in the Canary Islands and at the Catholic University based in Santiago, Chile. Slooh Classroom and Slooh Astrolab are products designed to offer K-12 and higher education an accessible, affordable way to interact with space. The lab manuals provide fully-designed classroom activities that explore celestial objects representing a robust sample of star clusters, nebulae, galaxies, stars, planets, comets and asteroids. Slooh’s education tools provide a unique online platform for the sharing of space content and access to live-hosted shows that discuss current astronomy events, creating a full STEAM experience.

Galaxy clusters in simulations of the local Universe: a matter of constraints

NASA Astrophysics Data System (ADS)

Sorce, Jenny G.; Tempel, Elmo

2018-06-01

To study the full formation and evolution history of galaxy clusters and their population, high-resolution simulations of the latter are flourishing. However, comparing observed clusters to the simulated ones on a one-to-one basis to refine the models and theories down to the details is non-trivial. The large variety of clusters limits the comparisons between observed and numerical clusters. Simulations resembling the local Universe down to the cluster scales permit pushing the limit. Simulated and observed clusters can be matched on a one-to-one basis for direct comparisons provided that clusters are well reproduced besides being in the proper large-scale environment. Comparing random and local Universe-like simulations obtained with differently grouped observational catalogues of peculiar velocities, this paper shows that the grouping scheme used to remove non-linear motions in the catalogues that constrain the simulations affects the quality of the numerical clusters. With a less aggressive grouping scheme - galaxies still falling on to clusters are preserved - combined with a bias minimization scheme, the mass of the dark matter haloes, simulacra for five local clusters - Virgo, Centaurus, Coma, Hydra, and Perseus - is increased by 39 per cent closing the gap with observational mass estimates. Simulacra are found on average in 89 per cent of the simulations, an increase of 5 per cent with respect to the previous grouping scheme. The only exception is Perseus. Since the Perseus-Pisces region is not well covered by the used peculiar velocity catalogue, the latest release lets us foresee a better simulacrum for Perseus in a near future.

Assessing the effect of an educational intervention program based on Health Belief Model on preventive behaviors of internet addiction

PubMed Central

Maheri, Aghbabak; Tol, Azar; Sadeghi, Roya

2017-01-01

INTRODUCTION: Internet addiction refers to the excessive use of the internet that causes mental, social, and physical problems. According to the high prevalence of internet addiction among university students, this study aimed to determine the effect of an educational intervention on preventive behaviors of internet addiction among Tehran University of Medical Sciences students. MATERIALS AND METHODS: This study was a quasi-experimental study conducted among female college students who live in the dormitories of Tehran University of Medical Sciences. Two-stage cluster sampling was used for selection of eighty participants in each study groups; data were collected using “Young's Internet Addiction” and unstructured questionnaire. Validity and reliability of unstructured questionnaire were evaluated by expert panel and were reported as Cronbach's alpha. Information of study groups before and 4 months after the intervention was compared using statistical methods by SPSS 16. RESULTS: After the intervention, the mean scores of internet addiction, perceived barriers construct, and the prevalence of internet addiction significantly decreased in the intervention group than that in the control group and the mean scores of knowledge and Health Belief Model (HBM) constructs (susceptibility, severity, benefits, self-efficacy) significantly increased. CONCLUSIONS: Education based on the HBM was effective on the reduction and prevention of internet addiction among female college students, and educational interventions in this field are highly recommended. PMID:28852654

Alcohol consumption during adolescence is associated with reduced grey matter volumes.

PubMed

Heikkinen, Noora; Niskanen, Eini; Könönen, Mervi; Tolmunen, Tommi; Kekkonen, Virve; Kivimäki, Petri; Tanila, Heikki; Laukkanen, Eila; Vanninen, Ritva

2017-04-01

Cognitive impairment has been associated with excessive alcohol use, but its neural basis is poorly understood. Chronic excessive alcohol use in adolescence may lead to neuronal loss and volumetric changes in the brain. Our objective was to compare the grey matter volumes of heavy- and light-drinking adolescents. This was a longitudinal study: heavy-drinking adolescents without an alcohol use disorder and their light-drinking controls were followed-up for 10 years using questionnaires at three time-points. Magnetic resonance imaging was conducted at the last time-point. The area near Kuopio University Hospital, Finland. The 62 participants were aged 22-28 years and included 35 alcohol users and 27 controls who had been followed-up for approximately 10 years. Alcohol use was measured by the Alcohol Use Disorders Identification Test (AUDIT)-C at three time-points during 10 years. Participants were selected based on their AUDIT-C score. Magnetic resonance imaging was conducted at the last time-point. Grey matter volume was determined and compared between heavy- and light-drinking groups using voxel-based morphometry on three-dimensional T1-weighted magnetic resonance images using predefined regions of interest and a threshold of P < 0.05, with small volume correction applied on cluster level. Grey matter volumes were significantly smaller among heavy-drinking participants in the bilateral anterior cingulate cortex, right orbitofrontal and frontopolar cortex, right superior temporal gyrus and right insular cortex compared to the control group (P < 0.05, family-wise error-corrected cluster level). Excessive alcohol use during adolescence appears to be associated with an abnormal development of the brain grey matter. Moreover, the structural changes detected in the insula of alcohol users may reflect a reduced sensitivity to alcohol's negative subjective effects. © 2016 Society for the Study of Addiction.

Hierarchical Partitioning of Metazoan Protein Conservation Profiles Provides New Functional Insights

PubMed Central

Witztum, Jonathan; Persi, Erez; Horn, David; Pasmanik-Chor, Metsada; Chor, Benny

2014-01-01

The availability of many complete, annotated proteomes enables the systematic study of the relationships between protein conservation and functionality. We explore this question based solely on the presence or absence of protein homologues (a.k.a. conservation profiles). We study 18 metazoans, from two distinct points of view: the human's and the fly's. Using the GOrilla gene ontology (GO) analysis tool, we explore functional enrichment of the “universal proteins”, those with homologues in all 17 other species, and of the “non-universal proteins”. A large number of GO terms are strongly enriched in both human and fly universal proteins. Most of these functions are known to be essential. A smaller number of GO terms, exhibiting markedly different properties, are enriched in both human and fly non-universal proteins. We further explore the non-universal proteins, whose conservation profiles are consistent with the “tree of life” (TOL consistent), as well as the TOL inconsistent proteins. Finally, we applied Quantum Clustering to the conservation profiles of the TOL consistent proteins. Each cluster is strongly associated with one or a small number of specific monophyletic clades in the tree of life. The proteins in many of these clusters exhibit strong functional enrichment associated with the “life style” of the related clades. Most previous approaches for studying function and conservation are “bottom up”, studying protein families one by one, and separately assessing the conservation of each. By way of contrast, our approach is “top down”. We globally partition the set of all proteins hierarchically, as described above, and then identify protein families enriched within different subdivisions. While supporting previous findings, our approach also provides a tool for discovering novel relations between protein conservation profiles, functionality, and evolutionary history as represented by the tree of life. PMID:24594619

Irie Classroom Toolbox: a study protocol for a cluster-randomised trial of a universal violence prevention programme in Jamaican preschools.

PubMed

Baker-Henningham, Helen; Vera-Hernández, Marcos; Alderman, Harold; Walker, Susan

2016-05-10

We aim to determine the effectiveness of a school-based violence prevention programme implemented in Jamaican preschools, on reducing the levels of aggression among children at school, and violence against children by teachers. This is a 2-arm, single-blind, cluster-randomised controlled trial with parallel assignment. Clusters are 76 preschools in Kingston, and all teachers and classrooms in the selected schools are included in the study. In addition, a random sample of up to 12 children in the 4-year-old classes have been selected for evaluation of child-level outcomes. The intervention involves training teachers in classroom behaviour management and in strategies to promote children's social-emotional competence. Training is delivered through five full-day workshops, monthly in-class coaching over 2 school terms, and weekly text messages. The primary outcome measures are: (1) observed levels of child aggression and (2) observed violence against children by teachers. Secondary outcomes include observations of the levels of children's prosocial behaviour and the quality of the classroom environment, teachers' reports of their mental health, teacher-reported child mental health, direct tests of children's self-regulation and child attendance. If this intervention were effective at improving the caregiving environment of young children in school, this would have significant implications for the prevention of child mental health problems, and prevention of violence against children in low and middle-income countries where services are often limited. The intervention is integrated into the school system and involves training existing staff, and thus, represents an appropriate strategy for large-scale implementation and benefits at the population level. Ethical consent for the study was given by the School of Psychology Ethics and Research Committee, Bangor University (ref: 2014-14167), and by the University of the West Indies Ethics Committee (ref: ECP 50,14/15). ISRCTN11968472; Pre-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

A Proposal to Investigate Outstanding Problems in Astronomy

NASA Technical Reports Server (NTRS)

Ford, Holland

2003-01-01

During the past year the ACS science team has concentrated on analyzing ACS observations, writing papers, and disseminating our results to the astronomy community at conferences and workshops around the world. We also have put considerable effort in getting our results to the public via public lectures and through press releases. Taking a very broad view of our program, we are investigating the evolution of galaxies and clusters of galaxies from their birth, approximately one billion years after the beginning of the Universe, to the present. We have found and characterized a population of galaxies that are no more than 1.4 billion years old. These may well be the Universe s first generation of infant galaxies. Looking at the Universe 500,000 years later, we see what appears to be a cluster of galaxies just beginning to form (a proto-cluster) around a luminous radio galaxy. Moving forward in time and closer to the present, we are studying clusters of galaxies that are less than half the age of the Universe. Our observations and analysis lead us to the important conclusion that the elliptical galaxies in these clusters must have had their last significant star formation some three billion years earlier, which is about the time when the proto-cluster was forming. Coming still closer to home, we are observing nearby massive clusters of galaxies that are approximately 12 billion years old. The gravity from these large aggregates of dark and luminous matter is so strong it warps space-time itself, and makes the cluster act as a cosmic telescope that magnifies the distant galaxies behind the cluster. We used the magnified (or lensed) galaxies to map the distribution of the dominant matter within the clusters, which is the so-called dark matter (the matter is invisible, and its nature is unknown). We also are using these cosmic telescopes to study the distant lensed galaxies that would otherwise be too small and too faint to be seen even by Hubble and the ACS.

Stabilizing ultrasmall Au clusters for enhanced photoredox catalysis.

PubMed

Weng, Bo; Lu, Kang-Qiang; Tang, Zichao; Chen, Hao Ming; Xu, Yi-Jun

2018-04-18

Recently, loading ligand-protected gold (Au) clusters as visible light photosensitizers onto various supports for photoredox catalysis has attracted considerable attention. However, the efficient control of long-term photostability of Au clusters on the metal-support interface remains challenging. Herein, we report a simple and efficient method for enhancing the photostability of glutathione-protected Au clusters (Au GSH clusters) loaded on the surface of SiO 2 sphere by utilizing multifunctional branched poly-ethylenimine (BPEI) as a surface charge modifying, reducing and stabilizing agent. The sequential coating of thickness controlled TiO 2 shells can further significantly improve the photocatalytic efficiency, while such structurally designed core-shell SiO 2 -Au GSH clusters-BPEI@TiO 2 composites maintain high photostability during longtime light illumination conditions. This joint strategy via interfacial modification and composition engineering provides a facile guideline for stabilizing ultrasmall Au clusters and rational design of Au clusters-based composites with improved activity toward targeting applications in photoredox catalysis.

Analyzing Sub-Classifications of Glaucoma via SOM Based Clustering of Optic Nerve Images.

PubMed

Yan, Sanjun; Abidi, Syed Sibte Raza; Artes, Paul Habib

2005-01-01

We present a data mining framework to cluster optic nerve images obtained by Confocal Scanning Laser Tomography (CSLT) in normal subjects and patients with glaucoma. We use self-organizing maps and expectation maximization methods to partition the data into clusters that provide insights into potential sub-classification of glaucoma based on morphological features. We conclude that our approach provides a first step towards a better understanding of morphological features in optic nerve images obtained from glaucoma patients and healthy controls.

The effect of note-taking skills training on the achievement motivation in learning on B.A students in Shahid Bahonar University of Kerman and Kerman University of Medical Sciences (Iran).

PubMed

Sharifi, Parvane; Rahmati, Abbas; Saber, Maryam

2013-10-01

To evaluate the effect of note-taking skills training on the achievement motivation in learning. The experimental study comprised graduate students of the 2010-11 batch at Kerman's Bahonar University and Kerman's Medical Sciences University, Iran. The study sample included 110 people; 55 in the test group, and 55 in the control group. They were randomly selected and replaced through the single-stage cluster sampling. To collect the data, a questionnaire was used. Pre-test was performed before the training session in two groups. After training course, a post-test was taken. For data analysis, the independent t-test, was used. The average pre-test score of the test group was 182 +/- 34.15, while for the control group it was 191 +/- 30.37 (p < 0.089). After the training, the post-test showed statistically significant change. The test group scored 220 +/- 20.94 against the controls who scored 195 +/- 27.26 (p < 0.001). The findings showed that achievement motivation in learning increased significantly after imparting training in note-taking skills. Authorities in the educational system should invest more for promotion of such skills.

The impact of clinical, demographic and risk factors on rates of HIV transmission: a population-based phylogenetic analysis in British Columbia, Canada.

PubMed

Poon, Art F Y; Joy, Jeffrey B; Woods, Conan K; Shurgold, Susan; Colley, Guillaume; Brumme, Chanson J; Hogg, Robert S; Montaner, Julio S G; Harrigan, P Richard

2015-03-15

The diversification of human immunodeficiency virus (HIV) is shaped by its transmission history. We therefore used a population based province wide HIV drug resistance database in British Columbia (BC), Canada, to evaluate the impact of clinical, demographic, and behavioral factors on rates of HIV transmission. We reconstructed molecular phylogenies from 27,296 anonymized bulk HIV pol sequences representing 7747 individuals in BC-about half the estimated HIV prevalence in BC. Infections were grouped into clusters based on phylogenetic distances, as a proxy for variation in transmission rates. Rates of cluster expansion were reconstructed from estimated dates of HIV seroconversion. Our criteria grouped 4431 individuals into 744 clusters largely separated with respect to risk factors, including large established clusters predominated by injection drug users and more-recently emerging clusters comprising men who have sex with men. The mean log10 viral load of an individual's phylogenetic neighborhood (composed of 5 other individuals with shortest phylogenetic distances) increased their odds of appearing in a cluster by >2-fold per log10 viruses per milliliter. Hotspots of ongoing HIV transmission can be characterized in near real time by the secondary analysis of HIV resistance genotypes, providing an important potential resource for targeting public health initiatives for HIV prevention. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Vote Stuffing Control in IPTV-based Recommender Systems

NASA Astrophysics Data System (ADS)

Bhatt, Rajen

Vote stuffing is a general problem in the functioning of the content rating-based recommender systems. Currently IPTV viewers browse various contents based on the program ratings. In this paper, we propose a fuzzy clustering-based approach to remove the effects of vote stuffing and consider only the genuine ratings for the programs over multiple genres. The approach requires only one authentic rating, which is generally available from recommendation system administrators or program broadcasters. The entire process is automated using fuzzy c-means clustering. Computational experiments performed over one real-world program rating database shows that the proposed approach is very efficient for controlling vote stuffing.

SeMPI: a genome-based secondary metabolite prediction and identification web server.

PubMed

Zierep, Paul F; Padilla, Natàlia; Yonchev, Dimitar G; Telukunta, Kiran K; Klementz, Dennis; Günther, Stefan

2017-07-03

The secondary metabolism of bacteria, fungi and plants yields a vast number of bioactive substances. The constantly increasing amount of published genomic data provides the opportunity for an efficient identification of gene clusters by genome mining. Conversely, for many natural products with resolved structures, the encoding gene clusters have not been identified yet. Even though genome mining tools have become significantly more efficient in the identification of biosynthetic gene clusters, structural elucidation of the actual secondary metabolite is still challenging, especially due to as yet unpredictable post-modifications. Here, we introduce SeMPI, a web server providing a prediction and identification pipeline for natural products synthesized by polyketide synthases of type I modular. In order to limit the possible structures of PKS products and to include putative tailoring reactions, a structural comparison with annotated natural products was introduced. Furthermore, a benchmark was designed based on 40 gene clusters with annotated PKS products. The web server of the pipeline (SeMPI) is freely available at: http://www.pharmaceutical-bioinformatics.de/sempi. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

"Learn Young, Learn Fair", a Stress Management Program for Fifth and Sixth Graders: Longitudinal Results from an Experimental Study

ERIC Educational Resources Information Center

Kraag, Gerda; Van Breukelen, Gerard J. P.; Kok, Gerjo; Hosman, Clemens

2009-01-01

Background: This study examined the effects of a universal stress management program (Learn Young, Learn Fair) on stress, coping, anxiety and depression in fifth and sixth grade children. Methods: Fifty-two schools (1467 children) participated in a clustered randomized controlled trial. Data was collected in the fall of 2002, the spring of 2003,…

The YouthMood Project: A Cluster Randomized Controlled Trial of an Online Cognitive Behavioral Program with Adolescents

ERIC Educational Resources Information Center

Calear, Alison L.; Christensen, Helen; Mackinnon, Andrew; Griffiths, Kathleen M.; O'Kearney, Richard

2009-01-01

The aim in the current study was to investigate the effectiveness of an online, self-directed cognitive-behavioral therapy program (MoodGYM) in preventing and reducing the symptoms of anxiety and depression in an adolescent school-based population. A cluster randomized controlled trial was conducted with 30 schools (N = 1,477) from across…

Impact of a Social-Emotional and Character Development Program on School-Level Indicators of Academic Achievement, Absenteeism, and Disciplinary Outcomes: A Matched-Pair, Cluster-Randomized, Controlled Trial

ERIC Educational Resources Information Center

Snyder, Frank; Flay, Brian; Vuchinich, Samuel; Acock, Alan; Washburn, Isaac; Beets, Michael; Li, Kin-Kit

2010-01-01

This article reports the effects of a comprehensive elementary school-based social-emotional and character education program on school-level achievement, absenteeism, and disciplinary outcomes utilizing a matched-pair, cluster-randomized, controlled design. The "Positive Action" Hawai'i trial included 20 racially/ethnically diverse…

Consanguinity and family clustering of male factor infertility in Lebanon.

PubMed

Inhorn, Marcia C; Kobeissi, Loulou; Nassar, Zaher; Lakkis, Da'ad; Fakih, Michael H

2009-04-01

To investigate the influence of consanguineous marriage on male factor infertility in Lebanon, where rates of consanguineous marriage remain high (29.6% among Muslims, 16.5% among Christians). Clinic-based, case-control study, using reproductive history, risk factor interview, and laboratory-based semen analysis. Two IVF clinics in Beirut, Lebanon, during an 8-month period (January-August 2003). One hundred twenty infertile male patients and 100 fertile male controls, distinguished by semen analysis and reproductive history. None. Standard clinical semen analysis. The rates of consanguineous marriage were relatively high among the study sample. Patients (46%) were more likely than controls (37%) to report first-degree (parental) and second-degree (grandparental) consanguinity. The study demonstrated a clear pattern of family clustering of male factor infertility, with patients significantly more likely than controls to report infertility among close male relatives (odds ratio = 2.58). Men with azoospermia and severe oligospermia showed high rates of both consanguinity (50%) and family clustering (41%). Consanguineous marriage is a socially supported institution throughout the Muslim world, yet its relationship to infertility is poorly understood. This study demonstrated a significant association between consanguinity and family clustering of male factor infertility cases, suggesting a strong genetic component.

Exploring Parental Bonding in BED and Non-BED Obesity Compared with Healthy Controls: Clinical, Personality and Psychopathology Correlates.

PubMed

Amianto, Federico; Ercole, Roberta; Abbate Daga, Giovanni; Fassino, Secondo

2016-05-01

Early inadequate attachment experiences are relevant co-factors in the development of obesity and Binge Eating Disorder (BED), which often concurs with obesity. The relationship of parental bonding with personality and psychopathology may influence treatment strategies for obese subjects, either affected or not with BED. In this study, 443 obese women (BMI ≥ 30 kg/m(2)), including 243 with and 200 without BED, and 158 female controls were assessed with regards to attachment, personality and eating psychopathology measures. Clusters obtained using the scores of the Parental Bonding Instrument (PBI) were compared with each other and with a control subjects' group. Lower scores of parental bonding distinguished obese subjects with respect to healthy controls. The cluster analysis revealed two clusters of parenting among obese subjects. The larger one displayed intermediate care and overprotection between controls and the smaller cluster, with the exception of paternal overprotection which is similar to controls. This larger cluster was characterized by low persistence and levels of psychopathology which are intermediate between healthy controls and the smaller cluster. The smaller cluster displayed lower care and higher overcontrol from both parents. It also displays more extreme personality traits (high novelty seeking and harm avoidance, and lower self-directedness and cooperativeness) and more severe eating and general psychopathology. Different parenting dynamics relate to different personality patterns and eating psychopathology of obese subjects, but not to binge eating conducts. Personality differences between parenting clusters are more extensive than those between BED and non-BED subgroups. The two different typologies of obese subjects based on parenting may be relevant for treatment personalization. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

The Efficacy of a Universal School-Based Prevention Program for Eating Disorders among German Adolescents: Results from a Randomized-Controlled Trial.

PubMed

Warschburger, Petra; Zitzmann, Jana

2018-06-01

Disordered eating is highly prevalent during adolescence and has a detrimental effect on further development. Effective prevention programs are needed to prevent unhealthy developmental trajectories. This study evaluated the efficacy of the POPS-program (POtsdam Prevention at Schools), a universal school-based eating disorder prevention program for adolescents. In a cluster-randomized design, we compared the intervention group receiving the prevention program to a waiting control group. Outcomes included indicators of disordered eating and relevant risk factors for eating disorders (body dissatisfaction, internalization of the thin ideal, perceived media pressure, perfectionism, emotional element of exercise, social comparison, and perceived teasing). Questionnaires were administered at the start of the intervention, 3 and 12 months post intervention. At baseline, 1112 adolescents aged 10 to 16 years participated (49% girls; 51% intervention group). Intention-to-treat analyses with the complete data set and per-protocol analyses as a completer analysis were performed. The intervention group showed a more favorable course compared to the control group regarding all observed risk factors for eating disorders except for perceived teasing. Effect sizes were small but comparable to other primary prevention programs. At 1-year follow-up, a small but significant effect on disordered eating was observed. Results of the per-protocol analyses were mostly confirmed by the intention-to-treat analyses. Results were promising for both genders although girls benefited more regarding disordered eating and internalization of the thin ideal. Further studies are warranted examining successful program elements and whether gender-specific programs are needed.

The Effects of Cluster-Based Mentoring Programme on Classroom Teaching Practices: Lessons from Pakistan

ERIC Educational Resources Information Center

Rizvi, Meher; Nagy, Philip

2016-01-01

This paper presents and evaluates a teacher training approach called the cluster-based mentoring programme (CBMP) for the professional development of government primary school teachers in Pakistan. The study sought to find differences in the teaching practices between districts where the CBMP was used (intervention) and control districts where it…

Evaluation of primary immunization coverage of infants under universal immunization programme in an urban area of bangalore city using cluster sampling and lot quality assurance sampling techniques.

PubMed

K, Punith; K, Lalitha; G, Suman; Bs, Pradeep; Kumar K, Jayanth

2008-07-01

Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Population-based cross-sectional study. Areas under Mathikere Urban Health Center. Children aged 12 months to 23 months. 220 in cluster sampling, 76 in lot quality assurance sampling. Percentages and Proportions, Chi square Test. (1) Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2) Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area.

Research on Modularized Design and Allocation of Infectious Disease Prevention and Control Equipment in China.

PubMed

Zhao, Xin; Wang, Yun-Dou; Zhang, Xiao-Feng; Gao, Shu-Tian; Guo, Li-Jun; Sun, Li-Na

2017-06-01

For the prevention and control of newly emergent or sudden infectious diseases, we built an on-site, modularized prevention and control system and tested the equipment by using the clustering analysis method. On the basis of this system, we propose a modular equipment allocation method and 4 applications of this method for different types of infectious disease prevention and control. This will help to improve the efficiency and productivity of anti-epidemic emergency forces and will provide strong technical support for implementing more universal and serialized equipment in China. (Disaster Med Public Health Preparedness. 2017;11:375-382).

Record-breaking ancient galaxy clusters

NASA Astrophysics Data System (ADS)

2003-12-01

A tale of two record-breaking clusters hi-res Size hi-res: 768 kb Credits: for RDCS1252: NASA, ESA, J.Blakeslee (Johns Hopkins Univ.), M.Postman (Space Telescope Science Inst.) and P.Rosati, Chris Lidman & Ricardo Demarco (European Southern Observ.) for TNJ1338: NASA, ESA, G.Miley (Leiden Observ.) and R.Overzier (Leiden Obs) A tale of two record-breaking clusters Looking back in time to when the universe was in its formative youth, the Advanced Camera for Surveys (ACS) aboard the NASA/ESA Hubble Space Telescope captured these revealing images of two galaxy clusters. The image at left, which is made with an additional infrared exposure taken with the European Southern Observatory’s Very Large Telescope, shows mature galaxies in a massive cluster that existed when the cosmos was 5000 million years old. The cluster, called RDCS1252.9-2927, is as massive as ‘300 trillion’ suns and is the most massive known cluster for its epoch. The image reveals the core of the cluster and is part of a much larger mosaic of the entire cluster. Dominating the core are a pair of large, reddish elliptical galaxies [near centre of image]. Their red colour indicates an older population of stars. Most of the stars are at least 1000 million years old. The two galaxies appear to be interacting and may eventually merge to form a larger galaxy that is comparable to the brightest galaxies seen in present-day clusters. The red galaxies surrounding the central pair are also cluster members. The cluster probably contains many thousands of galaxies, but only about 50 can be seen in this image. The full mosaic (heic0313d) reveals several hundred cluster members. Many of the other galaxies in the image, including several of the blue galaxies, are foreground or background galaxies. The colour-composite image was assembled from two observations (through i and z filters) taken between May and June 2002 by the ACS Wide Field Camera, and one image with the ISAAC instrument on the VLT taken in 2002 (combined from a J filter exposure and a K filter exposure). In the image at right, astronomers are seeing an embryonic cluster as it was when the universe was 1500 million years old. The young system, called TNJ1338-1942, is the most distant known developing cluster, or proto-cluster. It is dominated by a massive ‘baby galaxy’ - the green object. The cluster RDCS1252.9-2927 hi-res Size hi-res: 2611 kb Credits: NASA, ESA, J. Blakeslee (Johns Hopkins University), M. Postman (Space Telescope Science Institute) and P. Rosati, Chris Lidman & Ricardo Demarco (European Southern Observatory) The cluster RDCS1252.9-2927 Looking back in time to when the Universe was in its formative youth, the Advanced Camera for Surveys (ACS) aboard the NASA/ESA Hubble Space Telescope captured this revealing image of the galaxy cluster RDCS1252.9-2927. The image shows the entire cluster (1/15 of a degree, corresponding to about 7 million light-years, across). The cluster probably contains many thousands of galaxies. Most of the other galaxies in the image, including most of the blue galaxies, are foreground or background galaxies. The image, which is made with an additional infrared exposure taken with the European Southern Observatory’s Very Large Telescope, shows mature galaxies in a massive cluster that existed when the cosmos was 5000 million years old. The cluster, called RDCS1252.9-2927, is as massive as ‘300 trillion’ suns and is the most massive known cluster for its epoch. Dominating the core are a pair of large, reddish elliptical galaxies [near centre of image]. Their red colour indicates an older population of stars. Most of the stars are at least 1000 million years old. The two galaxies appear to be interacting and may eventually merge to form a larger galaxy that is comparable to the brightest galaxies seen in present-day clusters. The red galaxies surrounding the central pair are also cluster members. The colour-composite image was assembled from two observations (through i and z filters) taken between May and June 2002 by the ACS Wide Field Camera, and one image with the ISAAC instrument on the VLT taken in 2002 (combined from a J filter exposure and a K filter exposure). The embryonic cluster TNJ1338-1942 hi-res Size hi-res: 154 kb Credits: NASA, ESA, G. Miley (Leiden Observatory) and R. Overzier (Leiden Observatory) The embryonic cluster TNJ1338-1942 In this image astronomers are seeing an embryonic cluster as it was when the universe was 1500 million years old. The young system, called TNJ1338-1942, is the most distant known developing cluster, or proto-cluster. It is dominated by a massive ‘baby galaxy’ - the green object in the centre. The galaxy is producing powerful radio emissions, and is the brightest galaxy in the proto-cluster. The green colour indicates that the galaxy is emitting glowing hydrogen gas. Its clumpy appearance suggests that it is still in the process of forming. Smaller developing galaxies are scattered around the massive galaxy. The galaxy on the left of the massive galaxy is a foreground galaxy. The bright object in the upper half of the image is a foreground star. This colour-composite image was assembled from observations taken between July 8 and 12, 2002 by the ACS Wide Field Camera. The cluster RDCS1252.9-2927 hi-res Size hi-res: 259 kb Credits: NASA, ESA, J. Blakeslee (Johns Hopkins University), M. Postman (Space Telescope Science Institute) and P. Rosati, Chris Lidman & Ricardo Demarco (European Southern Observatory) The cluster RDCS1252.9-2927 Looking back in time to when the universe was in its formative youth, the Advanced Camera for Surveys (ACS) aboard the NASA/ESA Hubble Space Telescope captured this revealing image of the galaxy cluster RDCS1252.9-2927. This image is made with an additional infrared exposure taken with the European Southern Observatory’s Very Large Telescope, shows mature galaxies in a massive cluster that existed when the cosmos was 5000 million years old. The cluster, called RDCS1252.9-2927, is as massive as ‘300 trillion’ suns and is the most massive known cluster for its epoch. The image reveals the core of the cluster and is part of a much larger mosaic of the entire cluster. Dominating the core are a pair of large, reddish elliptical galaxies [near centre of image]. Their red colour indicates an older population of stars. Most of the stars are at least 1 000 million years old. The two galaxies appear to be interacting and may eventually merge to form a larger galaxy that is comparable to the brightest galaxies seen in present-day clusters. The red galaxies surrounding the central pair are also cluster members. The cluster probably contains many thousands of galaxies, but only about 50 can be seen in this image. The full mosaic reveals several hundred cluster members. Many of the other galaxies in the image, including several of the blue galaxies, are foreground or background galaxies. The colour-composite image was assembled from two observations (through i and z filters) taken between May and June 2002 by the ACS Wide Field Camera, and one image with the ISAAC instrument on the VLT taken in 2002 (combined from a J filter exposure and a K filter exposure). Looking back in time nearly 9000 million years, an international team of astronomers found mature galaxies in a young Universe. The galaxies are members of a cluster of galaxies that existed when the Universe was only 5000 million years old, or about 35 percent of its present age. This is compelling evidence that galaxies must have started forming just after the Big Bang and is bolstered by observations made by the same team of astronomers when they peered even farther back in time. The team found embryonic galaxies a mere 1500 million years after the birth of the cosmos, or 10 percent of the Universe's present age. The ‘baby galaxies’ reside in a still developing cluster, the most distant proto-cluster ever found. The Advanced Camera for Surveys (ACS) aboard the NASA/ESA Hubble Space Telescope was used to make the observations of the massive cluster, RDCS1252.9-2927, and the proto-cluster, TNJ1338-1942. Observations by NASA’s Chandra X-ray Observatory yielded the mass and heavy element content of RDCS1252.9-2927, the most massive known cluster for that epoch. These observations are part of a co-ordinated effort by the ACS science team to track the formation and evolution of clusters of galaxies over a broad span of cosmic time. The ACS was specially built for such studies of very distant objects. These findings support the theory that galaxies formed relatively early in the history of the cosmos. The existence of such massive clusters in the early Universe agrees with a cosmological model wherein clusters form by the merger of many sub-clusters in a Universe dominated by cold dark matter. The precise nature of cold dark matter, however, is still not known. The first Hubble study estimated that the galaxies in RCDS1252 formed the bulk of their stars more than 11 000 million years ago (redshifts greater than 3). The results were published in the 20 October 2003, issue of the Astrophysical Journal. The paper's lead author is John Blakeslee of the Johns Hopkins University in Baltimore, USA. The second Hubble study uncovered, for the first time, a proto-cluster of ‘infant galaxies’ that existed more than 12 000 million years ago (redshift 4.1). These galaxies are so young that astronomers can still see a flurry of stars forming within them. The galaxies are grouped around one large galaxy. These results will be published in the January 1, 2004 issue of Nature. The paper's lead author is George Miley of Leiden Observatory in the Netherlands. "Until recently people didn't think that clusters existed when the Universe was only about 5000 million years old," Blakeslee explained. "Even if there were such clusters," Miley added, "until recently astronomers thought it was almost impossible to find clusters that existed 8000 million years ago. In fact, no one really knew when clustering began. Now we can witness it." Both studies led the astronomers to conclude that these systems are the progenitors of the galaxy clusters seen today. "The cluster RDCS1252 looks like a present-day cluster," said Marc Postman of the Space Telescope Science Institute in Baltimore, USA, and co-author of both research papers. "In fact, if you were to put it next to a present-day cluster you wouldn't know which is which." ‘A tale of two clusters’ How can galaxies grow so fast after the Big Bang? "It is a case of the rich getting richer," Blakeslee said. "These clusters grew quickly because they are located in very dense regions, so there is enough material to build up the member galaxies very fast." This idea is bolstered by X-ray observations of the massive cluster RDCS1252. Chandra and the European Space Agency's XMM-Newton provided astronomers with the most accurate measurements to date of the properties of an enormous cloud of hot gas that pervades the massive cluster. This 70 million °C gas is a reservoir of most of the heavy elements in the cluster, and an accurate tracer of its total mass. A paper by Piero Rosati of the European Southern Observatory (ESO) and colleagues that presents the X-ray observations of RDCS1252 will be published in January 2004 in the Astronomical Journal. "Chandra's sharp vision resolved the shape of the hot gas halo and showed that RDCS1252 is very mature for its age," said Rosati, who discovered the cluster with the ROSAT X-ray telescope. RDCS1252 may contain many thousands of galaxies. Most of those galaxies, however, are too faint to detect, although the powerful ‘eyes’ of the ACS pinpointed several hundred of them. Observations using ESO's Very Large Telescope (VLT) provided a precise measurement of the distance to the cluster. The ACS enabled the researchers to determine the shapes and the colours of the 100 galaxies accurately, providing information on the ages of the stars residing in them. The ACS team estimated that most of the stars in the cluster were already formed by the time the Universe was about 2000 million years old. In addition X-ray observations showed that 5 000 million years after the Big Bang the surrounding hot gas had been enriched with heavy elements from these stars and swept away from the galaxies. If most of the galaxies in RDCS1252 have reached maturity and are settling into a quiet adulthood, the galaxies forming in the distant proto-cluster are in their energetic, unruly youth. The proto-cluster TN J1338 contains a massive embryonic galaxy surrounded by smaller developing galaxies, which look like dots in the Hubble image. The dominant galaxy is producing spectacular radio-emitting jets, fuelled by a supermassive black hole deep within the galaxy's nucleus. Interaction between these jets and the gas can stimulate a torrent of star birth. The discovery of the energetic radio galaxy by radio telescopes prompted astronomers to hunt for the smaller galaxies that make up the bulk of the cluster. "Massive clusters are the cities of the Universe, and the radio galaxies within them are the smokestacks we can use for finding them when they are just beginning to form," Miley said. The two findings underscore the power of combining observations from many different telescopes to provide views of the distant Universe over a range of wavelengths. Hubble’s advanced camera provided critical information on the structure of both distant galaxy clusters. Chandra's and XMM-Newton’s X-ray vision furnished the essential measurements of the primordial gas in which the galaxies in RDCS1252 are embedded, and accurate estimates of the total mass contained within that cluster. Large ground-based telescopes, like the VLT, provided precise measurements of the distance of both clusters as well as the chemical composition of the galaxies in them. The ACS team is conducting further observations of distant clusters to solidify our understanding of how these young clusters and their galaxies evolve into the shape of things seen today. Their planned observations include using near-infrared observations to analyse the star-formation rates in some of their clusters, including RDCS1252, in order to measure the cosmic history of star formation in these massive structures. The team is also searching the regions around several ultra-distant radio galaxies for additional examples of proto-clusters. The team's ultimate scientific goal is to establish a complete picture of cluster evolution beginning with their formation at the earliest epochs and detailing their evolution up to the present time.

Functionalizing graphene by embedded boron clusters

NASA Astrophysics Data System (ADS)

Quandt, Alexander; Özdoğan, Cem; Kunstmann, Jens; Fehske, Holger

2008-08-01

We present a model system that might serve as a blueprint for the controlled layout of graphene based nanodevices. The systems consists of chains of B7 clusters implanted in a graphene matrix, where the boron clusters are not directly connected. We show that the graphene matrix easily accepts these alternating B7-C6 chains and that the implanted boron components may dramatically modify the electronic properties of graphene based nanomaterials. This suggests a functionalization of graphene nanomaterials, where the semiconducting properties might be supplemented by parts of the graphene matrix itself, but the basic wiring will be provided by alternating chains of implanted boron clusters that connect these areas.

NASA Telescopes Help Identify Most Distant Galaxy Cluster

NASA Astrophysics Data System (ADS)

2011-01-01

WASHINGTON -- Astronomers have uncovered a burgeoning galactic metropolis, the most distant known in the early universe. This ancient collection of galaxies presumably grew into a modern galaxy cluster similar to the massive ones seen today. The developing cluster, named COSMOS-AzTEC3, was discovered and characterized by multi-wavelength telescopes, including NASA's Spitzer, Chandra and Hubble space telescopes, and the ground-based W.M. Keck Observatory and Japan's Subaru Telescope. "This exciting discovery showcases the exceptional science made possible through collaboration among NASA projects and our international partners," said Jon Morse, NASA's Astrophysics Division director at NASA Headquarters in Washington. Scientists refer to this growing lump of galaxies as a proto-cluster. COSMOS-AzTEC3 is the most distant massive proto-cluster known, and also one of the youngest, because it is being seen when the universe itself was young. The cluster is roughly 12.6 billion light-years away from Earth. Our universe is estimated to be 13.7 billion years old. Previously, more mature versions of these clusters had been spotted at 10 billion light-years away. The astronomers also found that this cluster is buzzing with extreme bursts of star formation and one enormous feeding black hole. "We think the starbursts and black holes are the seeds of the cluster," said Peter Capak of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "These seeds will eventually grow into a giant, central galaxy that will dominate the cluster -- a trait found in modern-day galaxy clusters." Capak is first author of a paper appearing in the Jan. 13 issue of the journal Nature. Most galaxies in our universe are bound together into clusters that dot the cosmic landscape like urban sprawls, usually centered around one old, monstrous galaxy containing a massive black hole. Astronomers thought that primitive versions of these clusters, still forming and clumping together, should exist in the early universe. But locating one proved difficult -- until now. Capak and his colleagues first used the Chandra X-ray Observatory and the United Kingdom's James Clerk Maxwell Telescope on Mauna Kea, Hawaii, to search for the black holes and bursts of star formation needed to form the massive galaxies at the centers of modern galaxy cities. The astronomers then used Hubble and the Subaru telescopes to estimate the distances to these objects, and look for higher densities of galaxies around them. Finally, the Keck telescope was used to confirm that these galaxies were at the same distance and part of the same galactic sprawl. Once the scientists found this lumping of galaxies, they measured the combined mass with the help of Spitzer. At this distance the optical light from stars is shifted, or stretched, to infrared wavelengths that can only be observed in outer space by Spitzer. The lump sum of the mass turned out to be a minimum of 400 billion suns -- enough to indicate that the astronomers had indeed uncovered a massive proto-cluster. The Spitzer observations also helped confirm a massive galaxy at the center of the cluster was forming stars at an impressive rate. Chandra X-ray observations were used to find and characterize the whopping black hole with a mass of more than 30 million suns. Massive black holes are common in present-day galaxy clusters, but this is the first time a feeding black hole of this heft has been linked to a cluster that is so young. Finally, the Institut de Radioastronomie Millimétrique's interferometer telescope in France and 30-meter telescope in Spain, along with the National Radio Astronomy Observatory's Very Large Array telescope in New Mexico, measured the amount of gas, or fuel for future star formation, in the cluster. The results indicate the cluster will keep growing into a modern city of galaxies. "It really did take a village of telescopes to nail this cluster," said Capak. "Observations across the electromagnetic spectrum, from X-ray to millimeter wavelengths, were all critical in providing a comprehensive view of the cluster's many facets." COSMOS-AzTEC3, located in the constellation Sextans, is named after the region where it was found, called COSMOS after the Cosmic Evolution Survey. AzTEC is the name of the camera used on the James Clerk Maxwell Telescope -- this camera is now on its way to the Large Millimeter Telescope located in Mexico's Puebla state. For more information about NASA's Spitzer, Chandra and Hubble space telescopes, visit: http://www.nasa.gov/chandra http://www.nasa.gov/spitzer http://www.nasa.gov/hubble

The application of heterogeneous cluster grouping to reflective writing for medical humanities literature study to enhance students' empathy, critical thinking, and reflective writing.

PubMed

Liao, Hung-Chang; Wang, Ya-Huei

2016-09-02

To facilitate interdisciplinary collaboration and to make connections between patients' diseases and their social/cultural contexts, the study examined whether the use of heterogeneous cluster grouping in reflective writing for medical humanities literature acquisition could have positive effects on medical university students in terms of empathy, critical thinking, and reflective writing. A 15-week quasi-experimental design was conducted to investigate the learning outcomes. After conducting cluster algorithms, heterogeneous learning clusters (experimental group; n = 43) and non-heterogeneous learning clusters (control group; n = 43) were derived for a medical humanities literature study. Before and after the intervention, an Empathy Scale in Patient Care (ES-PC), a critical thinking disposition assessment (CTDA-R), and a reflective writing test were administered to both groups. The findings showed that on the empathy scale, significant differences in the "behavioral empathy," "affective empathy," and overall sections existed between the post-test mean scores of the experimental group and those of the control group, but such differences did not exist in "intelligent empathy." Regarding critical thinking, there were significant differences in "systematicity and analyticity," "skepticism and well-informed," "maturity and skepticism," and overall sections. As for reflective writing, significant differences existed in "ideas," "voice and point of view," "critical thinking and representation," "depth of reflection on personal growth," and overall sections, but not in "focus and context structure" and "language and conventions." This study outlined an alternative for using heterogeneous cluster grouping in reflective writing about medical humanities literature to facilitate interdisciplinary cooperation to provide more humanizing medical care.

Differential effect of exposure-based therapy and cognitive therapy on post-traumatic stress disorder symptom clusters: A randomized controlled trial.

PubMed

Horesh, Danny; Qian, Meng; Freedman, Sara; Shalev, Arieh

2017-06-01

A question remains regarding differential effects of exposure-based versus non-exposure-based therapies on specific post-traumatic stress disorder (PTSD) symptom clusters. Traumatized emergency room patients were randomized to receive prolonged exposure (PE) or cognitive therapy (CT) without exposure. PE/CT had no differential effect on individual symptom clusters, and change in total PTSD score remained significant even after controlling for the reductions in all three symptom clusters. In addition, baseline levels of PTSD avoidance/intrusion/hyperarousal did not moderate the effects of PE and CT on total PTSD symptom scores. Taken together, these findings challenge the notion that PE and CT are specifically, and differentially, useful in treating one particular PTSD symptom cluster. Despite their different theoretical backgrounds and techniques, the notion that PE and CT (without exposure) target different PTSD symptoms was not confirmed in this study. Thus, both interventions may in fact be equally effective for treating intrusion, avoidance and hyperarousal symptoms. Baseline levels of avoidance, intrusion and hyperarousal may not be good a priori indicators for PTSD treatment selection. The effect of PE and CT on PTSD as a whole does not seem to depend on a reduction in any specific symptom cluster. These findings indicate that exposure and non-exposure interventions may lead to similar results in terms of reductions in specific PTSD symptoms. It is quite possible that individual PTSD clusters may respond to therapy in an inter-related fashion, with one cluster affecting the other. © 2016 The British Psychological Society.

Effects of promoting longer-term and exclusive breastfeeding on childhood eating attitudes: a cluster-randomized trial.

PubMed

Skugarevsky, Oleg; Wade, Kaitlin H; Richmond, Rebecca C; Martin, Richard M; Tilling, Kate; Patel, Rita; Vilchuck, Konstantin; Bogdanovich, Natalia; Sergeichick, Natalia; Davey Smith, George; Gillman, Matthew W; Oken, Emily; Kramer, Michael S

2014-08-01

Observational studies suggest that breastfeeding benefits later maternal child-feeding practices, which in turn may contribute to positive eating attitudes. We investigated the effect of a randomized intervention to increase duration and exclusivity of breastfeeding on pre-adolescent eating attitudes. Long-term follow-up of the Promotion of Breastfeeding Intervention Trial (PROBIT), a cluster-randomized trial in 31 maternity hospitals and affiliated polyclinics in Belarus. Sites were randomly assigned an experimental intervention to promote longer duration and exclusivity of breastfeeding in mothers who initiated breastfeeding (n = 16 sites), or a control intervention of continuing usual care (n = 15 sites); 17 046 healthy infants were enrolled in 1996-7, of whom 13 751 (80.7%) completed the Children's Eating Attitude Test (ChEAT) at 11.5 years of age. A ChEAT score ≥ 22.5 (85th percentile) was used as an indicator of problematic eating attitudes. Analysis was based on intention-to-treat, accounting for clustering within hospitals/clinics. Compared with the control arm, the experimental intervention substantially increased breastfeeding exclusivity (43.3% vs 6.4% exclusively breastfed at 3 months of age) and duration of any breastfeeding throughout infancy. The proportion of children with ChEAT scores ≥ 22.5 was lower in the experimental than control arm (boys 11.4% vs 17.2%; girls 18.5% vs 23.4%) [cluster-adjusted odds ratio (OR), boys: 0.44; 95% confidence interval (CI): 0.21,0.93; girls: 0.51; 95% CI: 0.27,0.99). Results were robust to adjustment for potential confounders and using a ChEAT score ≥ 25.5 (91st percentile) as the outcome (OR: 0.53; 95% CI: 0.28,1.03). An intervention to improve the duration and exclusivity of breastfeeding among term infants in Belarus was associated with a reduction in problematic eating attitudes at 11.5 years of age. © The Author 2014; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

Peste des Petits Ruminants risk factors and space-time clusters in Mymensingh, Bangladesh.

PubMed

Rony, M S; Rahman, A K M A; Alam, M M; Dhand, N; Ward, M P

2017-12-01

Using a hospital-based case-control study design, our aim was to identify risk factors for-and space-time clusters of-Peste des Petits Ruminants (PPR) in Mymensingh, Bangladesh. Three hundred and eighty PPR cases diagnosed between January 2005 and December 2014 at the Bangladesh Agricultural University Veterinary Teaching Hospital (BAUVTH) were selected; three controls per case from BAUVTH were then selected (n = 1,048). From records, data extracted included information on date of report, location, age, breed, sex and body weight of goats. A mixed multivariable logistic regression model was built to identify risk factors. Location was included as a random effect and season and demographic variables as fixed effects. The approximate geographic coordinates of locations were collected, and the scan statistic (Bernoulli model) was used to identify space-time clusters of PPR. Compared with goats <4 months of age, the odds of PPR were 3 (95% confidence interval [CI]: 1.95-4.66), 1.9 (CI: 1.34-2.76) and 1.8 times (95% CI: 1.19-2.58) greater in goats aged 4-6, >6-12 and >12-24 months, respectively. The occurrence of PPR was also significantly higher (odds ratio [OR] 3.2; 95% CI: 1.15-8.59) in the Jamunapari breed than Black Bengals. Significantly higher odds of PPR were observed in winter (OR 1.6; 95% CI: 1.06-2.14) and the monsoon season (OR 1.5; 95% CI: 1.04-2.11) compared with the post-monsoon season. Two significant (p < .05) space-time clusters were identified between 2 December 2006 and 6 September 2007 (two locations) and 28 November 2006 and 13 February 2007 (five locations). Peste des Petits Ruminants is endemic in Bangladesh, but also occurs as discrete outbreaks. Control efforts-such as vaccination-should focus on high-risk groups (4-24 months of age, Jamunapari breed), prior to the onset of winter and the monsoon season so as to increase immunity during high-risk periods, and focus on disease hotspots. © 2017 Blackwell Verlag GmbH.

Assessing the effectiveness of a patient-centred computer-based clinic intervention, Health-E You/Salud iTu, to reduce health disparities in unintended pregnancies among Hispanic adolescents: study protocol for a cluster randomised control trial

PubMed Central

Tebb, Kathleen P.; Rodriguez, Felicia; Pollack, Lance M.; Trieu, Sang Leng; Hwang, Loris; Puffer, Maryjane; Adams, Sally; Ozer, Elizabeth M.; Brindis, Claire D.

2018-01-01

Introduction Teen pregnancy rates in the USA remain higher than any other industrialised nation, and pregnancies among Hispanic adolescents are disproportionately high. Computer-based interventions represent a promising approach to address sexual health and contraceptive use disparities. Preliminary findings have demonstrated that the Health-E You/Salud iTu, computer application (app) is feasible to implement, acceptable to Latina adolescents and improves sexual health knowledge and interest in selecting an effective contraceptive method when used in conjunction with a healthcare visit. The app is now ready for efficacy testing. The purpose of this manuscript is to describe patient-centred approaches used both in developing and testing the Health-E You app and to present the research methods used to evaluate its effectiveness in improving intentions to use an effective method of contraception as well as actual contraceptive use. Methods and analysis This study is designed to assess the effectiveness of a patient-centred computer-based clinic intervention, Health-E You/Salud iTu, on its ability to reduce health disparities in unintended pregnancies among Latina adolescent girls. This study uses a cluster randomised control trial design in which 18 school-based health centers from the Los Angeles Unified School District were randomly assigned, at equal chance, to either the intervention (Health-E You app) or control group. Analyses will examine differences between the control and intervention group’s knowledge of and attitudes towards contraceptive use, receipt of contraception at the clinic visit and self-reported use of contraception at 3-month and 6-month follow-ups. The study began enrolling participants in August 2016, and a total of 1400 participants (700 per treatment group) are expected to be enrolled by March 2018. Ethics and dissemination Ethics approval was obtained through the University of California, San Francisco Institutional Review Board. Results of this trial will be submitted for publication in peer-reviewed journals. This study is registered with the US National Institutes of Health. Trial registration number NCT02847858. PMID:29326184

A novel approach for measuring residential socioeconomic ...

EPA Pesticide Factsheets

Individual-level characteristics, including socioeconomic status, have been associated with poor metabolic and cardiovascular health; however, residential area-level characteristics may also independently contribute to health status. In the current study, we used hierarchical clustering to aggregate 444 US Census block groups in Durham, Orange, and Wake Counties, NC, USA into six homogeneous clusters of similar characteristics based on 12 demographic factors. We assigned 2254 cardiac catheterization patients to these clusters based on residence at first catheterization. After controlling for individual age, sex, smoking status, and race, there were elevated odds of patients being obese (odds ratio (OR) = 1.92, 95% confidence intervals (CI) = 1.39, 2.67), and having diabetes (OR = 2.19, 95% CI = 1.57, 3.04), congestive heart failure (OR = 1.99, 95% CI = 1.39, 2.83), and hypertension (OR = 2.05, 95% CI = 1.38, 3.11) in a cluster that was urban, impoverished, and unemployed, compared to a cluster that was urban with a low percentage of people that were impoverished or unemployed. Our findings demonstrate the feasibility of applying hierarchical clustering to an assessment of area-level characteristics and that living in impoverished, urban residential clusters may have an adverse impact on health. The study highlights the importance of neighborhood characteristics on health. After controlling for individual-level demographic factors, significant differences in dise

White Matter Tract Integrity in Alzheimer's Disease vs. Late Onset Bipolar Disorder and Its Correlation with Systemic Inflammation and Oxidative Stress Biomarkers.

PubMed

Besga, Ariadna; Chyzhyk, Darya; Gonzalez-Ortega, Itxaso; Echeveste, Jon; Graña-Lecuona, Marina; Graña, Manuel; Gonzalez-Pinto, Ana

2017-01-01

Background: Late Onset Bipolar Disorder (LOBD) is the development of Bipolar Disorder (BD) at an age above 50 years old. It is often difficult to differentiate from other aging dementias, such as Alzheimer's Disease (AD), because they share cognitive and behavioral impairment symptoms. Objectives: We look for WM tract voxel clusters showing significant differences when comparing of AD vs. LOBD, and its correlations with systemic blood plasma biomarkers (inflammatory, neurotrophic factors, and oxidative stress). Materials: A sample of healthy controls (HC) ( n = 19), AD patients ( n = 35), and LOBD patients ( n = 24) was recruited at the Alava University Hospital. Blood plasma samples were obtained at recruitment time and analyzed to extract the inflammatory, oxidative stress, and neurotrophic factors. Several modalities of MRI were acquired for each subject, Methods: Fractional anisotropy (FA) coefficients are obtained from diffusion weighted imaging (DWI). Tract based spatial statistics (TBSS) finds FA skeleton clusters of WM tract voxels showing significant differences for all possible contrasts between HC, AD, and LOBD. An ANOVA F -test over all contrasts is carried out. Results of F -test are used to mask TBSS detected clusters for the AD > LOBD and LOBD > AD contrast to select the image clusters used for correlation analysis. Finally, Pearson's correlation coefficients between FA values at cluster sites and systemic blood plasma biomarker values are computed. Results: The TBSS contrasts with by ANOVA F -test has identified strongly significant clusters in the forceps minor, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and cingulum gyrus. The correlation analysis of these tract clusters found strong negative correlation of AD with the nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) blood biomarkers. Negative correlation of AD and positive correlation of LOBD with inflammation biomarker IL6 was also found. Conclusion: TBSS voxel clusters tract atlas localizations are consistent with greater behavioral impairment and mood disorders in LOBD than in AD. Correlation analysis confirms that neurotrophic factors (i.e., NGF, BDNF) play a great role in AD while are absent in LOBD pathophysiology. Also, correlation results of IL1 and IL6 suggest stronger inflammatory effects in LOBD than in AD.

Embrace the Dark Side: Advancing the Dark Energy Survey

NASA Astrophysics Data System (ADS)

Suchyta, Eric

The Dark Energy Survey (DES) is an ongoing cosmological survey intended to study the properties of the accelerated expansion of the Universe. In this dissertation, I present work of mine that has advanced the progress of DES. First is an introduction, which explores the physics of the cosmos, as well as how DES intends to probe it. Attention is given to developing the theoretical framework cosmologists use to describe the Universe, and to explaining observational evidence which has furnished our current conception of the cosmos. Emphasis is placed on the dark sector - dark matter and dark energy - the content of the Universe not explained by the Standard Model of particle physics. As its name suggests, the Dark Energy Survey has been specially designed to measure the properties of dark energy. DES will use a combination of galaxy cluster, weak gravitational lensing, angular clustering, and supernovae measurements to derive its state of the art constraints, each of which is discussed in the text. The work described in this dissertation includes science measurements directly related to the first three of these probes. The dissertation presents my contributions to the readout and control system of the Dark Energy Camera (DECam); the name of this software is SISPI. SISPI uses client-server and publish-subscribe communication patterns to coordinate and command actions among the many hardware components of DECam - the survey instrument for DES, a 570 megapixel CCD camera, mounted at prime focus of the Blanco 4-m Telescope. The SISPI work I discuss includes coding applications for DECam's filter changer mechanism and hexapod, as well as developing the Scripts Editor, a GUI application for DECam users to edit and export observing sequence SISPI can load and execute. Next, the dissertation describes the processing of early DES data, which I contributed. This furnished the data products used in the first-completed DES science analysis, and contributed to improving the collaboration-wide treatment of the data. The science measurements themselves are also detailed. We verified DES's capabilities for performing weak lensing analyses by measuring the masses of four galaxy clusters, finding consistency with previous measurements, and utilized DECam's wide field-of-view for a photometric study of filament-like structures in the fields. Finally, my recent work with Balrog is presented. Balrog is a simulation toolkit for embedding fake objects into real survey images in order to correct for systematic biases. We have used Balrog to extend DES galaxy clustering measurements down to fainter limits than previously possible, finding results consistent with higher-resolution space-based data. The methodology used in this analysis generalizes beyond galaxy clustering alone, and promises to be useful in future imaging survey measurements.

The Hubble Space Telescope Cluster Supernova Survey. III. Correlated

Science.gov Websites

Properties SAO/NASA ADS Astronomy Abstract Service Title: The Hubble Space Telescope Cluster Street, Cambridge, MA 02138, USA), AF(Department of Physics and Astronomy, University of Utah, Salt Lake , USA), AH(Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka

The Online Bioinformatics Resources Collection at the University of Pittsburgh Health Sciences Library System--a one-stop gateway to online bioinformatics databases and software tools.

PubMed

Chen, Yi-Bu; Chattopadhyay, Ansuman; Bergen, Phillip; Gadd, Cynthia; Tannery, Nancy

2007-01-01

To bridge the gap between the rising information needs of biological and medical researchers and the rapidly growing number of online bioinformatics resources, we have created the Online Bioinformatics Resources Collection (OBRC) at the Health Sciences Library System (HSLS) at the University of Pittsburgh. The OBRC, containing 1542 major online bioinformatics databases and software tools, was constructed using the HSLS content management system built on the Zope Web application server. To enhance the output of search results, we further implemented the Vivísimo Clustering Engine, which automatically organizes the search results into categories created dynamically based on the textual information of the retrieved records. As the largest online collection of its kind and the only one with advanced search results clustering, OBRC is aimed at becoming a one-stop guided information gateway to the major bioinformatics databases and software tools on the Web. OBRC is available at the University of Pittsburgh's HSLS Web site (http://www.hsls.pitt.edu/guides/genetics/obrc).

A fully nonparametric estimator of the marginal survival function based on case–control clustered age-at-onset data

PubMed Central

Gorfine, Malka; Bordo, Nadia; Hsu, Li

2017-01-01

Summary Consider a popular case–control family study where individuals with a disease under study (case probands) and individuals who do not have the disease (control probands) are randomly sampled from a well-defined population. Possibly right-censored age at onset and disease status are observed for both probands and their relatives. For example, case probands are men diagnosed with prostate cancer, control probands are men free of prostate cancer, and the prostate cancer history of the fathers of the probands is also collected. Inherited genetic susceptibility, shared environment, and common behavior lead to correlation among the outcomes within a family. In this article, a novel nonparametric estimator of the marginal survival function is provided. The estimator is defined in the presence of intra-cluster dependence, and is based on consistent smoothed kernel estimators of conditional survival functions. By simulation, it is shown that the proposed estimator performs very well in terms of bias. The utility of the estimator is illustrated by the analysis of case–control family data of early onset prostate cancer. To our knowledge, this is the first article that provides a fully nonparametric marginal survival estimator based on case–control clustered age-at-onset data. PMID:27436674

Welcome to pandoraviruses at the ‘Fourth TRUC’ club

PubMed Central

Sharma, Vikas; Colson, Philippe; Chabrol, Olivier; Scheid, Patrick; Pontarotti, Pierre; Raoult, Didier

2015-01-01

Nucleocytoplasmic large DNA viruses, or representatives of the proposed order Megavirales, belong to families of giant viruses that infect a broad range of eukaryotic hosts. Megaviruses have been previously described to comprise a fourth monophylogenetic TRUC (things resisting uncompleted classification) together with cellular domains in the universal tree of life. Recently described pandoraviruses have large (1.9–2.5 MB) and highly divergent genomes. In the present study, we updated the classification of pandoraviruses and other reported giant viruses. Phylogenetic trees were constructed based on six informational genes. Hierarchical clustering was performed based on a set of informational genes from Megavirales members and cellular organisms. Homologous sequences were selected from cellular organisms using TimeTree software, comprising comprehensive, and representative sets of members from Bacteria, Archaea, and Eukarya. Phylogenetic analyses based on three conserved core genes clustered pandoraviruses with phycodnaviruses, exhibiting their close relatedness. Additionally, hierarchical clustering analyses based on informational genes grouped pandoraviruses with Megavirales members as a super group distinct from cellular organisms. Thus, the analyses based on core conserved genes revealed that pandoraviruses are new genuine members of the ‘Fourth TRUC’ club, encompassing distinct life forms compared with cellular organisms. PMID:26042093

Welcome to pandoraviruses at the 'Fourth TRUC' club.

PubMed

Sharma, Vikas; Colson, Philippe; Chabrol, Olivier; Scheid, Patrick; Pontarotti, Pierre; Raoult, Didier

2015-01-01

Nucleocytoplasmic large DNA viruses, or representatives of the proposed order Megavirales, belong to families of giant viruses that infect a broad range of eukaryotic hosts. Megaviruses have been previously described to comprise a fourth monophylogenetic TRUC (things resisting uncompleted classification) together with cellular domains in the universal tree of life. Recently described pandoraviruses have large (1.9-2.5 MB) and highly divergent genomes. In the present study, we updated the classification of pandoraviruses and other reported giant viruses. Phylogenetic trees were constructed based on six informational genes. Hierarchical clustering was performed based on a set of informational genes from Megavirales members and cellular organisms. Homologous sequences were selected from cellular organisms using TimeTree software, comprising comprehensive, and representative sets of members from Bacteria, Archaea, and Eukarya. Phylogenetic analyses based on three conserved core genes clustered pandoraviruses with phycodnaviruses, exhibiting their close relatedness. Additionally, hierarchical clustering analyses based on informational genes grouped pandoraviruses with Megavirales members as a super group distinct from cellular organisms. Thus, the analyses based on core conserved genes revealed that pandoraviruses are new genuine members of the 'Fourth TRUC' club, encompassing distinct life forms compared with cellular organisms.

Cluster-Randomized Controlled Trial Evaluating the Effectiveness of Computer-Assisted Intervention Delivered by Educators for Children with Speech Sound Disorders

ERIC Educational Resources Information Center

McLeod, Sharynne; Baker, Elise; McCormack, Jane; Wren, Yvonne; Roulstone, Sue; Crowe, Kathryn; Masso, Sarah; White, Paul; Howland, Charlotte

2017-01-01

Purpose: The aim was to evaluate the effectiveness of computer-assisted input-based intervention for children with speech sound disorders (SSD). Method: The Sound Start Study was a cluster-randomized controlled trial. Seventy-nine early childhood centers were invited to participate, 45 were recruited, and 1,205 parents and educators of 4- and…

Effects of Mindfulness-Based Stress Reduction on the Mental Health of Clinical Clerkship Students: A Cluster-Randomized Controlled Trial.

PubMed

van Dijk, Inge; Lucassen, Peter L B J; Akkermans, Reinier P; van Engelen, Baziel G M; van Weel, Chris; Speckens, Anne E M

2017-07-01

To examine the effect of mindfulness-based stress reduction training (MBSR) on the mental health of medical students during clinical clerkships. Between February 2011 and May 2014, the authors conducted a cluster-randomized controlled trial of clerkships as usual (CAU) and clerkships with additional MBSR in medical students during their first year of clinical clerkships at a Dutch university medical center. MBSR consisted of eight weekly two-hour sessions, comprising didactic teaching, meditation exercises, and group dialogues. Students completed online assessments at baseline and after 3, 7, 12, 15, and 20 months. Outcome measures were psychological distress, positive mental health, life satisfaction, physician empathy, mindfulness skills, and dysfunctional cognitions as measured by validated tools. Of 232 eligible students, 167 students (72%) participated and were randomized by clerkship group into MBSR (n = 83) or CAU (n = 84). The MBSR group reported a small reduction of psychological distress (P = .03, Cohen's d = 0.20) and dysfunctional cognitions (P = .05, Cohen's d = 0.18) and a moderate increase of positive mental health (P = .002, Cohen's d = 0.44), life satisfaction (P = .01, Cohen's d = 0.51), and mindfulness skills (P = .05, Cohen's d = 0.35) compared with CAU during the 20-month follow-up. The authors detected no significant effect on physician empathy (P = .18, Cohen's d = 0.27). MBSR appeared feasible and acceptable to medical clerkship students and resulted in a small to moderate improvement of mental health compared with CAU over the 20-month follow-up.

Case-control geographic clustering for residential histories accounting for risk factors and covariates

PubMed Central

2006-01-01

Background Methods for analyzing space-time variation in risk in case-control studies typically ignore residential mobility. We develop an approach for analyzing case-control data for mobile individuals and apply it to study bladder cancer in 11 counties in southeastern Michigan. At this time data collection is incomplete and no inferences should be drawn – we analyze these data to demonstrate the novel methods. Global, local and focused clustering of residential histories for 219 cases and 437 controls is quantified using time-dependent nearest neighbor relationships. Business address histories for 268 industries that release known or suspected bladder cancer carcinogens are analyzed. A logistic model accounting for smoking, gender, age, race and education specifies the probability of being a case, and is incorporated into the cluster randomization procedures. Sensitivity of clustering to definition of the proximity metric is assessed for 1 to 75 k nearest neighbors. Results Global clustering is partly explained by the covariates but remains statistically significant at 12 of the 14 levels of k considered. After accounting for the covariates 26 Local clusters are found in Lapeer, Ingham, Oakland and Jackson counties, with the clusters in Ingham and Oakland counties appearing in 1950 and persisting to the present. Statistically significant focused clusters are found about the business address histories of 22 industries located in Oakland (19 clusters), Ingham (2) and Jackson (1) counties. Clusters in central and southeastern Oakland County appear in the 1930's and persist to the present day. Conclusion These methods provide a systematic approach for evaluating a series of increasingly realistic alternative hypotheses regarding the sources of excess risk. So long as selection of cases and controls is population-based and not geographically biased, these tools can provide insights into geographic risk factors that were not specifically assessed in the case-control study design. PMID:16887016

Hybrid clustering based fuzzy structure for vibration control - Part 1: A novel algorithm for building neuro-fuzzy system

NASA Astrophysics Data System (ADS)

Nguyen, Sy Dzung; Nguyen, Quoc Hung; Choi, Seung-Bok

2015-01-01

This paper presents a new algorithm for building an adaptive neuro-fuzzy inference system (ANFIS) from a training data set called B-ANFIS. In order to increase accuracy of the model, the following issues are executed. Firstly, a data merging rule is proposed to build and perform a data-clustering strategy. Subsequently, a combination of clustering processes in the input data space and in the joint input-output data space is presented. Crucial reason of this task is to overcome problems related to initialization and contradictory fuzzy rules, which usually happen when building ANFIS. The clustering process in the input data space is accomplished based on a proposed merging-possibilistic clustering (MPC) algorithm. The effectiveness of this process is evaluated to resume a clustering process in the joint input-output data space. The optimal parameters obtained after completion of the clustering process are used to build ANFIS. Simulations based on a numerical data, 'Daily Data of Stock A', and measured data sets of a smart damper are performed to analyze and estimate accuracy. In addition, convergence and robustness of the proposed algorithm are investigated based on both theoretical and testing approaches.

Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE): A Cluster-Randomized Pragmatic Trial of a Multifactorial Fall Injury Prevention Strategy: Design and Methods.

PubMed

Bhasin, Shalender; Gill, Thomas M; Reuben, David B; Latham, Nancy K; Gurwitz, Jerry H; Dykes, Patricia; McMahon, Siobhan; Storer, Thomas W; Duncan, Pamela W; Ganz, David A; Basaria, Shehzad; Miller, Michael E; Travison, Thomas G; Greene, Erich J; Dziura, James; Esserman, Denise; Allore, Heather; Carnie, Martha B; Fagan, Maureen; Hanson, Catherine; Baker, Dorothy; Greenspan, Susan L; Alexander, Neil; Ko, Fred; Siu, Albert L; Volpi, Elena; Wu, Albert W; Rich, Jeremy; Waring, Stephen C; Wallace, Robert; Casteel, Carri; Magaziner, Jay; Charpentier, Peter; Lu, Charles; Araujo, Katy; Rajeevan, Haseena; Margolis, Scott; Eder, Richard; McGloin, Joanne M; Skokos, Eleni; Wiggins, Jocelyn; Garber, Lawrence; Clauser, Steven B; Correa-De-Araujo, Rosaly; Peduzzi, Peter

2017-10-14

Fall injuries are a major cause of morbidity and mortality among older adults. We describe the design of a pragmatic trial to compare the effectiveness of an evidence-based, patient-centered multifactorial fall injury prevention strategy to an enhanced usual care. Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE) is a 40-month cluster-randomized, parallel-group, superiority, pragmatic trial being conducted at 86 primary care practices in 10 healthcare systems across USA. The 86 practices were randomized to intervention or control group using covariate-based constrained randomization, stratified by healthcare system. Participants are community-living persons, ≥70 years, at increased risk for serious fall injuries. The intervention is a co-management model in which a nurse Falls Care Manager performs multifactorial risk assessments, develops individualized care plans, which include surveillance, follow-up evaluation, and intervention strategies. Control group receives enhanced usual care, with clinicians and patients receiving evidence-based information on falls prevention. Primary outcome is serious fall injuries, operationalized as those leading to medical attention (non-vertebral fractures, joint dislocation, head injury, lacerations, and other major sequelae). Secondary outcomes include all fall injuries, all falls, and well-being (concern for falling; anxiety and depressive symptoms; physical function and disability). Target sample size was 5,322 participants to provide 90% power to detect 20% reduction in primary outcome rate relative to control. Trial enrolled 5451 subjects in 20 months. Intervention and follow-up are ongoing. The findings of the STRIDE study will have important clinical and policy implications for the prevention of fall injuries in older adults. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Psychoanalytic-Interactional Therapy versus Psychodynamic Therapy by Experts for Personality Disorders: A Randomized Controlled Efficacy-Effectiveness Study in Cluster B Personality Disorders.

PubMed

Leichsenring, Falk; Masuhr, Oliver; Jaeger, Ulrich; Rabung, Sven; Dally, Andreas; Dümpelmann, Michael; Fricke-Neef, Christian; Steinert, Christiane; Streeck, Ulrich

2016-01-01

With regard to cluster B personality disorders, most psychotherapeutic treatments focus on borderline personality disorder. Evidence-based treatments for patients with other cluster B personality disorders are not yet available. Psychoanalytic-interactional therapy (PIT) represents a transdiagnostic treatment for severe personality disorders. PIT has been applied in clinical practice for many years and has proven effective in open studies. In a randomized controlled trial, we compared manual-guided PIT to nonmanualized pychodynamic therapy by experts in personality disorders (E-PDT) in patients with cluster B personality disorders. In an inpatient setting, patients with cluster B personality disorders were randomly assigned to manual-guided PIT (n = 64) or nonmanualized E-PDT (n = 58). In addition, a quasi-experimental control condition was used (n = 46) including both patients receiving treatment as usual and patients waiting for treatment. Primary outcomes were level of personality organization and overall psychological distress. As secondary outcomes, depression, anxiety and interpersonal problems were examined. No significant improvements were found in the control patients. Both PIT and E-PDT achieved significant improvements in all outcome measures and were superior to the control condition. No differences were found between PIT and E-PDT in any outcome measure at the end of treatment. The type of cluster B personality disorder had no impact on the results. In an inpatient setting, both PIT and E-PDT proved to be superior to a control condition in cluster B personality disorders. In a head-to-head comparison, both treatments appeared to be equally effective. Further research on the treatment of cluster B personality disorders is required. © 2016 S. Karger AG, Basel.

Improving quality of life through the routine use of the patient concerns inventory for head and neck cancer patients: a cluster preference randomized controlled trial.

PubMed

Rogers, Simon N; Lowe, Derek; Lowies, Cher; Yeo, Seow Tien; Allmark, Christine; Mcavery, Dominic; Humphris, Gerald M; Flavel, Robert; Semple, Cherith; Thomas, Steven J; Kanatas, Anastasios

2018-04-18

The consequences of treatment for Head and Neck cancer (HNC) patients has profound detrimental impacts such as impaired QOL, emotional distress, delayed recovery and frequent use of healthcare. The aim of this trial is to determine if the routine use of the Patients Concerns Inventory (PCI) package in review clinics during the first year following treatment can improve overall quality of life, reduce the social-emotional impact of cancer and reduce levels of distress. Furthermore, we aim to describe the economic costs and benefits of using the PCI. This will be a cluster preference randomised control trial with consultants either 'using' or 'not using' the PCI package at clinic. It will involve two centres Leeds and Liverpool. 416 eligible patients from at least 10 consultant clusters are required to show a clinically meaningful difference in the primary outcome. The primary outcome is the percentage of participants with less than good overall quality of life at the final one-year clinic as measured by the University of Washington QOL questionnaire version 4 (UWQOLv4). Secondary outcomes at one-year are the mean social-emotional subscale (UWQOLv4) score, Distress Thermometer (DT) score ≥ 4, and key health economic measures (QALY-EQ-5D-5 L; CSRI). This trial will provide knowledge on the effectiveness of a consultation intervention package based around the PCI used at routine follow-up clinics following treatment of head and neck cancer with curative intent. If this intervention is (cost) effective for patients, the next step will be to promote wider use of this approach as standard care in clinical practice. 32,382. Clinical Trials Identifier, NCT03086629 . Version 3.0, 1st July 2017.

Coordinated control of active and reactive power of distribution network with distributed PV cluster via model predictive control

NASA Astrophysics Data System (ADS)

Ji, Yu; Sheng, Wanxing; Jin, Wei; Wu, Ming; Liu, Haitao; Chen, Feng

2018-02-01

A coordinated optimal control method of active and reactive power of distribution network with distributed PV cluster based on model predictive control is proposed in this paper. The method divides the control process into long-time scale optimal control and short-time scale optimal control with multi-step optimization. The models are transformed into a second-order cone programming problem due to the non-convex and nonlinear of the optimal models which are hard to be solved. An improved IEEE 33-bus distribution network system is used to analyse the feasibility and the effectiveness of the proposed control method

The Effectiveness of Educational Interventions to Enhance the Adoption of Fee-Based Arsenic Testing in Bangladesh: A Cluster Randomized Controlled Trial

PubMed Central

George, Christine Marie; Inauen, Jennifer; Rahman, Sheikh Masudur; Zheng, Yan

2013-01-01

Arsenic (As) testing could help 22 million people, using drinking water sources that exceed the Bangladesh As standard, to identify safe sources. A cluster randomized controlled trial was conducted to evaluate the effectiveness of household education and local media in the increasing demand for fee-based As testing. Randomly selected households (N = 452) were divided into three interventions implemented by community workers: 1) fee-based As testing with household education (HE); 2) fee-based As testing with household education and a local media campaign (HELM); and 3) fee-based As testing alone (Control). The fee for the As test was US$ 0.28, higher than the cost of the test (US$ 0.16). Of households with untested wells, 93% in both intervention groups HE and HELM purchased an As test, whereas only 53% in the control group. In conclusion, fee-based As testing with household education is effective in the increasing demand for As testing in rural Bangladesh. PMID:23716409

The effectiveness of educational interventions to enhance the adoption of fee-based arsenic testing in Bangladesh: a cluster randomized controlled trial.

PubMed

George, Christine Marie; Inauen, Jennifer; Rahman, Sheikh Masudur; Zheng, Yan

2013-07-01

Arsenic (As) testing could help 22 million people, using drinking water sources that exceed the Bangladesh As standard, to identify safe sources. A cluster randomized controlled trial was conducted to evaluate the effectiveness of household education and local media in the increasing demand for fee-based As testing. Randomly selected households (N = 452) were divided into three interventions implemented by community workers: 1) fee-based As testing with household education (HE); 2) fee-based As testing with household education and a local media campaign (HELM); and 3) fee-based As testing alone (Control). The fee for the As test was US$ 0.28, higher than the cost of the test (US$ 0.16). Of households with untested wells, 93% in both intervention groups HE and HELM purchased an As test, whereas only 53% in the control group. In conclusion, fee-based As testing with household education is effective in the increasing demand for As testing in rural Bangladesh.

Photometric and integrated spectral study of the young open clusters Pismis 22, NGC 6178, NGC 6216 and Ruprecht 130

NASA Astrophysics Data System (ADS)

Piatti, A. E.; Clariá, J. J.; Bica, E.

2000-08-01

We present CCD observations in the B, V , and I passbands obtained for stars in the fields of the open clusters Pismis 22, NGC 6178, NGC 6216, and Ruprecht 130, projected not far from the Galactic centre (|l| < 30̂, |b| < 2̂). The sample consists of about 790 stars reaching down to V ~ 18-19 mag. From the analysis of the colour magnitude diagrams, we confirmed the physical reality of the clusters and derived their reddening, distance and age. In addition, we obtained flux-calibrated integrated spectra in the range 3500-9200 Å for the cluster sample. The equivalent widths of the Balmer lines provided us with age estimates, while the comparison with template spectra allowed us to derive both foreground reddening and age. The photometric and spectroscopic results reveal that the four studied objects are young open clusters with ages ranging between 35 and 50 Myr. The clusters, located between 1.0 kpc and 4.3 kpc from the Sun, are affected by different amounts of interstellar visual absorption (0.6 ≃ Av ≃ 6.0). Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la Repúbica Argentina and the National Universities of La Plata, Córdoba, and San Juan, Argentina, and at the University of Toronto (David Dunlap Observatory) 24-inch telescope, Las Campanas, Chile. Tables 3-6 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Generalizing MOND to explain the missing mass in galaxy clusters

NASA Astrophysics Data System (ADS)

Hodson, Alistair O.; Zhao, Hongsheng

2017-02-01

Context. MOdified Newtonian Dynamics (MOND) is a gravitational framework designed to explain the astronomical observations in the Universe without the inclusion of particle dark matter. MOND, in its current form, cannot explain the missing mass in galaxy clusters without the inclusion of some extra mass, be it in the form of neutrinos or non-luminous baryonic matter. We investigate whether the MOND framework can be generalized to account for the missing mass in galaxy clusters by boosting gravity in high gravitational potential regions. We examine and review Extended MOND (EMOND), which was designed to increase the MOND scale acceleration in high potential regions, thereby boosting the gravity in clusters. Aims: We seek to investigate galaxy cluster mass profiles in the context of MOND with the primary aim at explaining the missing mass problem fully without the need for dark matter. Methods: Using the assumption that the clusters are in hydrostatic equilibrium, we can compute the dynamical mass of each cluster and compare the result to the predicted mass of the EMOND formalism. Results: We find that EMOND has some success in fitting some clusters, but overall has issues when trying to explain the mass deficit fully. We also investigate an empirical relation to solve the cluster problem, which is found by analysing the cluster data and is based on the MOND paradigm. We discuss the limitations in the text.

Using hierarchical cluster models to systematically identify groups of jobs with similar occupational questionnaire response patterns to assist rule-based expert exposure assessment in population-based studies.

PubMed

Friesen, Melissa C; Shortreed, Susan M; Wheeler, David C; Burstyn, Igor; Vermeulen, Roel; Pronk, Anjoeka; Colt, Joanne S; Baris, Dalsu; Karagas, Margaret R; Schwenn, Molly; Johnson, Alison; Armenti, Karla R; Silverman, Debra T; Yu, Kai

2015-05-01

Rule-based expert exposure assessment based on questionnaire response patterns in population-based studies improves the transparency of the decisions. The number of unique response patterns, however, can be nearly equal to the number of jobs. An expert may reduce the number of patterns that need assessment using expert opinion, but each expert may identify different patterns of responses that identify an exposure scenario. Here, hierarchical clustering methods are proposed as a systematic data reduction step to reproducibly identify similar questionnaire response patterns prior to obtaining expert estimates. As a proof-of-concept, we used hierarchical clustering methods to identify groups of jobs (clusters) with similar responses to diesel exhaust-related questions and then evaluated whether the jobs within a cluster had similar (previously assessed) estimates of occupational diesel exhaust exposure. Using the New England Bladder Cancer Study as a case study, we applied hierarchical cluster models to the diesel-related variables extracted from the occupational history and job- and industry-specific questionnaires (modules). Cluster models were separately developed for two subsets: (i) 5395 jobs with ≥1 variable extracted from the occupational history indicating a potential diesel exposure scenario, but without a module with diesel-related questions; and (ii) 5929 jobs with both occupational history and module responses to diesel-relevant questions. For each subset, we varied the numbers of clusters extracted from the cluster tree developed for each model from 100 to 1000 groups of jobs. Using previously made estimates of the probability (ordinal), intensity (µg m(-3) respirable elemental carbon), and frequency (hours per week) of occupational exposure to diesel exhaust, we examined the similarity of the exposure estimates for jobs within the same cluster in two ways. First, the clusters' homogeneity (defined as >75% with the same estimate) was examined compared to a dichotomized probability estimate (<5 versus ≥5%; <50 versus ≥50%). Second, for the ordinal probability metric and continuous intensity and frequency metrics, we calculated the intraclass correlation coefficients (ICCs) between each job's estimate and the mean estimate for all jobs within the cluster. Within-cluster homogeneity increased when more clusters were used. For example, ≥80% of the clusters were homogeneous when 500 clusters were used. Similarly, ICCs were generally above 0.7 when ≥200 clusters were used, indicating minimal within-cluster variability. The most within-cluster variability was observed for the frequency metric (ICCs from 0.4 to 0.8). We estimated that using an expert to assign exposure at the cluster-level assignment and then to review each job in non-homogeneous clusters would require ~2000 decisions per expert, in contrast to evaluating 4255 unique questionnaire patterns or 14983 individual jobs. This proof-of-concept shows that using cluster models as a data reduction step to identify jobs with similar response patterns prior to obtaining expert ratings has the potential to aid rule-based assessment by systematically reducing the number of exposure decisions needed. While promising, additional research is needed to quantify the actual reduction in exposure decisions and the resulting homogeneity of exposure estimates within clusters for an exposure assessment effort that obtains cluster-level expert assessments as part of the assessment process. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

A New Approach for Simulating Galaxy Cluster Properties

NASA Astrophysics Data System (ADS)

Arieli, Y.; Rephaeli, Y.; Norman, M. L.

2008-08-01

We describe a subgrid model for including galaxies into hydrodynamical cosmological simulations of galaxy cluster evolution. Each galaxy construct—or galcon—is modeled as a physically extended object within which star formation, galactic winds, and ram pressure stripping of gas are modeled analytically. Galcons are initialized at high redshift (z ~ 3) after galaxy dark matter halos have formed but before the cluster has virialized. Each galcon moves self-consistently within the evolving cluster potential and injects mass, metals, and energy into intracluster (IC) gas through a well-resolved spherical interface layer. We have implemented galcons into the Enzo adaptive mesh refinement code and carried out a simulation of cluster formation in a ΛCDM universe. With our approach, we are able to economically follow the impact of a large number of galaxies on IC gas. We compare the results of the galcon simulation with a second, more standard simulation where star formation and feedback are treated using a popular heuristic prescription. One advantage of the galcon approach is explicit control over the star formation history of cluster galaxies. Using a galactic SFR derived from the cosmic star formation density, we find the galcon simulation produces a lower stellar fraction, a larger gas core radius, a more isothermal temperature profile, and a flatter metallicity gradient than the standard simulation, in better agreement with observations.

Molecular-based rapid inventories of sympatric diversity: a comparison of DNA barcode clustering methods applied to geography-based vs clade-based sampling of amphibians.

PubMed

Paz, Andrea; Crawford, Andrew J

2012-11-01

Molecular markers offer a universal source of data for quantifying biodiversity. DNA barcoding uses a standardized genetic marker and a curated reference database to identify known species and to reveal cryptic diversity within wellsampled clades. Rapid biological inventories, e.g. rapid assessment programs (RAPs), unlike most barcoding campaigns, are focused on particular geographic localities rather than on clades. Because of the potentially sparse phylogenetic sampling, the addition of DNA barcoding to RAPs may present a greater challenge for the identification of named species or for revealing cryptic diversity. In this article we evaluate the use of DNA barcoding for quantifying lineage diversity within a single sampling site as compared to clade-based sampling, and present examples from amphibians. We compared algorithms for identifying DNA barcode clusters (e.g. species, cryptic species or Evolutionary Significant Units) using previously published DNA barcode data obtained from geography-based sampling at a site in Central Panama, and from clade-based sampling in Madagascar. We found that clustering algorithms based on genetic distance performed similarly on sympatric as well as clade-based barcode data, while a promising coalescent-based method performed poorly on sympatric data. The various clustering algorithms were also compared in terms of speed and software implementation. Although each method has its shortcomings in certain contexts, we recommend the use of the ABGD method, which not only performs fairly well under either sampling method, but does so in a few seconds and with a user-friendly Web interface.

Emergence of jams in the generalized totally asymmetric simple exclusion process

NASA Astrophysics Data System (ADS)

Derbyshev, A. E.; Povolotsky, A. M.; Priezzhev, V. B.

2015-02-01

The generalized totally asymmetric exclusion process (TASEP) [J. Stat. Mech. (2012) P05014, 10.1088/1742-5468/2012/05/P05014] is an integrable generalization of the TASEP equipped with an interaction, which enhances the clustering of particles. The process interpolates between two extremal cases: the TASEP with parallel update and the process with all particles irreversibly merging into a single cluster moving as an isolated particle. We are interested in the large time behavior of this process on a ring in the whole range of the parameter λ controlling the interaction. We study the stationary state correlations, the cluster size distribution, and the large-time fluctuations of integrated particle current. When λ is finite, we find the usual TASEP-like behavior: The correlation length is finite; there are only clusters of finite size in the stationary state and current fluctuations belong to the Kardar-Parisi-Zhang universality class. When λ grows with the system size, so does the correlation length. We find a nontrivial transition regime with clusters of all sizes on the lattice. We identify a crossover parameter and derive the large deviation function for particle current, which interpolates between the case considered by Derrida-Lebowitz and a single-particle diffusion.

Effect of village-wide use of long-lasting insecticidal nets on visceral Leishmaniasis vectors in India and Nepal: a cluster randomized trial.

PubMed

Picado, Albert; Das, Murari L; Kumar, Vijay; Kesari, Shreekant; Dinesh, Diwakar S; Roy, Lalita; Rijal, Suman; Das, Pradeep; Rowland, Mark; Sundar, Shyam; Coosemans, Marc; Boelaert, Marleen; Davies, Clive R

2010-01-26

Visceral leishmaniasis (VL) control in the Indian subcontinent is currently based on case detection and treatment, and on vector control using indoor residual spraying (IRS). The use of long-lasting insecticidal nets (LN) has been postulated as an alternative or complement to IRS. Here we tested the impact of comprehensive distribution of LN on the density of Phlebotomus argentipes in VL-endemic villages. A cluster-randomized controlled trial with household P. argentipes density as outcome was designed. Twelve clusters from an ongoing LN clinical trial--three intervention and three control clusters in both India and Nepal--were selected on the basis of accessibility and VL incidence. Ten houses per cluster selected on the basis of high pre-intervention P. argentipes density were monitored monthly for 12 months after distribution of LN using CDC light traps (LT) and mouth aspiration methods. Ten cattle sheds per cluster were also monitored by aspiration. A random effect linear regression model showed that the cluster-wide distribution of LNs significantly reduced the P. argentipes density/house by 24.9% (95% CI 1.80%-42.5%) as measured by means of LTs. The ongoing clinical trial, designed to measure the impact of LNs on VL incidence, will confirm whether LNs should be adopted as a control strategy in the regional VL elimination programs. The entomological evidence described here provides some evidence that LNs could be usefully deployed as part of the VL control program. ClinicalTrials.gov CT-2005-015374.

Variable Stars in Large Magellanic Cloud Globular Clusters. III. Reticulum

NASA Astrophysics Data System (ADS)

Kuehn, Charles A.; Dame, Kyra; Smith, Horace A.; Catelan, Márcio; Jeon, Young-Beom; Nemec, James M.; Walker, Alistair R.; Kunder, Andrea; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2013-06-01

This is the third in a series of papers studying the variable stars in old globular clusters in the Large Magellanic Cloud. The primary goal of this series is to look at how the characteristics and behavior of RR Lyrae stars in Oosterhoff-intermediate systems compare to those of their counterparts in Oosterhoff-I/II systems. In this paper we present the results of our new time-series BVI photometric study of the globular cluster Reticulum. We found a total of 32 variables stars (22 RRab, 4 RRc, and 6 RRd stars) in our field of view. We present photometric parameters and light curves for these stars. We also present physical properties, derived from Fourier analysis of light curves, for some of the RR Lyrae stars. We discuss the Oosterhoff classification of Reticulum and use our results to re-derive the distance modulus and age of the cluster. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Astronomy Fun with Mobile Devices

NASA Astrophysics Data System (ADS)

Pilachowski, Catherine A.; Morris, Frank

2016-01-01

Those mobile devices your students bring to class can do more that tweet and text. Engage your students with these web-based astronomy learning tools that allow students to manipulate astronomical data to learn important concepts. The tools are HTML5, CSS3, Javascript-based applications that provide access to the content on iPad and Android tablets. With "Three Color" students can combine monochrome astronomical images taken through different color filters or in different wavelength regions into a single color image. "Star Clusters" allows students to compare images of clusters with a pre-defined template of colors and sizes to compare clusters of different ages. An adaptation of Travis Rector's "NovaSearch" allows students to examine images of the central regions of the Andromeda Galaxy to find novae and to measure the time over which the nova fades away. New additions to our suite of applications allow students to estimate the surface temperatures of exoplanets and the probability of life elsewhere in the Universe. Further information and access to these web-based tools are available at www.astro.indiana.edu/ala/.

The Sources of Strength Australia Project: study protocol for a cluster randomised controlled trial.

PubMed

Calear, Alison L; Brewer, Jacqueline L; Batterham, Philip J; Mackinnon, Andrew; Wyman, Peter A; LoMurray, Mark; Shand, Fiona; Kazan, Dominique; Christensen, Helen

2016-07-26

The school system has been identified as an ideal setting for the implementation of prevention and early intervention programs for suicide. However, in Australia, suicide-prevention programs that are routinely delivered in the schools are lacking. Internationally, evidence exists for the effectiveness of peer-led interventions that take a social connectedness approach to improve help-seeking for suicide. The aim of the current trial is to test the effectiveness of the Sources of Strength program to promote help-seeking for suicide in adolescents in Australian high schools. This study is a two-arm, cluster-randomised, controlled trial that will compare the evidence-based Sources of Strength program to a wait-list control condition. Sixteen Australian high schools will be recruited to the trial, with all adolescents in years 7 to 10 (12-16 years of age) invited to participate. Peer leaders from intervention-condition schools will receive training in the Sources of Strength program and will integrate positive messages, across 3 months, with the support of adult advisors. Activities may take the form of class presentations, posters, videos, and messages on social media sites and will aim to change help-seeking norms, strengthen youth-adult connections, and promote positive coping. The primary outcome measure for the study is help-seeking intentions, whereas secondary outcomes include help-seeking behaviour, help-seeking attitudes and norms, referral of distressed peers, availability of adult help, positive coping, and suicidal behaviour. Data will be collected pre-intervention, post-intervention (after the initial 3 months of messaging), and at the end of the first (6-month follow-up) and the second year after implementation (18-month follow-up). Primary analyses will compare changes in help-seeking intentions for the intervention condition relative to the wait-list control condition using mixed-effect repeated-measures analyses to account for clustering within schools. If proven effective, this universal social connectedness program for suicide could be more widely delivered in Australian high schools, providing a valuable new resource. The Sources of Strength program has the potential to significantly contribute to the mental health of young people in Australia by improving help-seeking for suicide. The findings from this research will also contribute to the evidence-base for peer-leadership programs internationally. Australian New Zealand Clinical Trials Registry, ACTRN12616000048482 . Registered on 19 January 2016.

Detecting space-time cancer clusters using residential histories

NASA Astrophysics Data System (ADS)

Jacquez, Geoffrey M.; Meliker, Jaymie R.

2007-04-01

Methods for analyzing geographic clusters of disease typically ignore the space-time variability inherent in epidemiologic datasets, do not adequately account for known risk factors (e.g., smoking and education) or covariates (e.g., age, gender, and race), and do not permit investigation of the latency window between exposure and disease. Our research group recently developed Q-statistics for evaluating space-time clustering in cancer case-control studies with residential histories. This technique relies on time-dependent nearest neighbor relationships to examine clustering at any moment in the life-course of the residential histories of cases relative to that of controls. In addition, in place of the widely used null hypothesis of spatial randomness, each individual's probability of being a case is instead based on his/her risk factors and covariates. Case-control clusters will be presented using residential histories of 220 bladder cancer cases and 440 controls in Michigan. In preliminary analyses of this dataset, smoking, age, gender, race and education were sufficient to explain the majority of the clustering of residential histories of the cases. Clusters of unexplained risk, however, were identified surrounding the business address histories of 10 industries that emit known or suspected bladder cancer carcinogens. The clustering of 5 of these industries began in the 1970's and persisted through the 1990's. This systematic approach for evaluating space-time clustering has the potential to generate novel hypotheses about environmental risk factors. These methods may be extended to detect differences in space-time patterns of any two groups of people, making them valuable for security intelligence and surveillance operations.

Task shifting of frontline community health workers for cardiovascular risk reduction: design and rationale of a cluster randomised controlled trial (DISHA study) in India.

PubMed

Jeemon, Panniyammakal; Narayanan, Gitanjali; Kondal, Dimple; Kahol, Kashvi; Bharadwaj, Ashok; Purty, Anil; Negi, Prakash; Ladhani, Sulaiman; Sanghvi, Jyoti; Singh, Kuldeep; Kapoor, Deksha; Sobti, Nidhi; Lall, Dorothy; Manimunda, Sathyaprakash; Dwivedi, Supriya; Toteja, Gurudyal; Prabhakaran, Dorairaj

2016-03-15

Effective task-shifting interventions targeted at reducing the global cardiovascular disease (CVD) epidemic in low and middle-income countries (LMICs) are urgently needed. DISHA is a cluster randomised controlled trial conducted across 10 sites (5 in phase 1 and 5 in phase 2) in India in 120 clusters. At each site, 12 clusters were randomly selected from a district. A cluster is defined as a small village with 250-300 households and well defined geographical boundaries. They were then randomly allocated to intervention and control clusters in a 1:1 allocation sequence. If any of the intervention and control clusters were <10 km apart, one was dropped and replaced with another randomly selected cluster from the same district. The study included a representative baseline cross-sectional survey, development of a structured intervention model, delivery of intervention for a minimum period of 18 months by trained frontline health workers (mainly Anganwadi workers and ASHA workers) and a post intervention survey in a representative sample. The study staff had no information on intervention allocation until the completion of the baseline survey. In order to ensure comparability of data across sites, the DISHA study follows a common protocol and manual of operation with standardized measurement techniques. Our study is the largest community based cluster randomised trial in low and middle-income country settings designed to test the effectiveness of 'task shifting' interventions involving frontline health workers for cardiovascular risk reduction. CTRI/2013/10/004049 . Registered 7 October 2013.

The Atacama Cosmology Telescope: The Two-season ACTPol Sunyaev–Zel’dovich Effect Selected Cluster Catalog

NASA Astrophysics Data System (ADS)

Hilton, Matt; Hasselfield, Matthew; Sifón, Cristóbal; Battaglia, Nicholas; Aiola, Simone; Bharadwaj, V.; Bond, J. Richard; Choi, Steve K.; Crichton, Devin; Datta, Rahul; Devlin, Mark J.; Dunkley, Joanna; Dünner, Rolando; Gallardo, Patricio A.; Gralla, Megan; Hincks, Adam D.; Ho, Shuay-Pwu P.; Hubmayr, Johannes; Huffenberger, Kevin M.; Hughes, John P.; Koopman, Brian J.; Kosowsky, Arthur; Louis, Thibaut; Madhavacheril, Mathew S.; Marriage, Tobias A.; Maurin, Loïc; McMahon, Jeff; Miyatake, Hironao; Moodley, Kavilan; Næss, Sigurd; Nati, Federico; Newburgh, Laura; Niemack, Michael D.; Oguri, Masamune; Page, Lyman A.; Partridge, Bruce; Schmitt, Benjamin L.; Sievers, Jon; Spergel, David N.; Staggs, Suzanne T.; Trac, Hy; van Engelen, Alexander; Vavagiakis, Eve M.; Wollack, Edward J.

2018-03-01

We present a catalog of 182 galaxy clusters detected through the Sunyaev–Zel’dovich (SZ) effect by the Atacama Cosmology Telescope in a contiguous 987.5 deg2 field. The clusters were detected as SZ decrements by applying a matched filter to 148 GHz maps that combine the original ACT equatorial survey with data from the first two observing seasons using the ACTPol receiver. Optical/IR confirmation and redshift measurements come from a combination of large public surveys and our own follow-up observations. Where necessary, we measured photometric redshifts for clusters using a pipeline that achieves accuracy Δz/(1 + z) = 0.015 when tested on Sloan Digital Sky Survey data. Under the assumption that clusters can be described by the so-called universal pressure profile (UPP) and its associated mass scaling law, the full signal-to-noise ratio > 4 sample spans the mass range 1.6< {M}500{{c}}UPP}/{10}14 {M}ȯ < 9.1, with median {M}500{{c}}UPP}=3.1× {10}14 {M}ȯ . The sample covers the redshift range 0.1 < z < 1.4 (median z = 0.49), and 28 clusters are new discoveries (median z = 0.80). We compare our catalog with other overlapping cluster samples selected using the SZ, optical, and X-ray wavelengths. We find that the ratio of the UPP-based SZ mass to richness-based weak-lensing mass is < {M}500{{c}}UPP}> /< {M}500{{c}}λ {WL}> =0.68+/- 0.11. After applying this calibration, the mass distribution for clusters with M 500c > 4 × 1014 M ⊙ is consistent with the number of such clusters found in the South Pole Telescope SZ survey.

Jellyfish: Evidence of Extreme Ram-pressure Stripping in Massive Galaxy Clusters

NASA Astrophysics Data System (ADS)

Ebeling, H.; Stephenson, L. N.; Edge, A. C.

2014-02-01

Ram-pressure stripping by the gaseous intracluster medium has been proposed as the dominant physical mechanism driving the rapid evolution of galaxies in dense environments. Detailed studies of this process have, however, largely been limited to relatively modest examples affecting only the outermost gas layers of galaxies in nearby and/or low-mass galaxy clusters. We here present results from our search for extreme cases of gas-galaxy interactions in much more massive, X-ray selected clusters at z > 0.3. Using Hubble Space Telescope snapshots in the F606W and F814W passbands, we have discovered dramatic evidence of ram-pressure stripping in which copious amounts of gas are first shock compressed and then removed from galaxies falling into the cluster. Vigorous starbursts triggered by this process across the galaxy-gas interface and in the debris trail cause these galaxies to temporarily become some of the brightest cluster members in the F606W passband, capable of outshining even the Brightest Cluster Galaxy. Based on the spatial distribution and orientation of systems viewed nearly edge-on in our survey, we speculate that infall at large impact parameter gives rise to particularly long-lasting stripping events. Our sample of six spectacular examples identified in clusters from the Massive Cluster Survey, all featuring M F606W < -21 mag, doubles the number of such systems presently known at z > 0.2 and facilitates detailed quantitative studies of the most violent galaxy evolution in clusters. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs GO-10491, -10875, -12166, and -12884.

A Clustering Based Approach for Observability and Controllability Analysis for Optimal Placement of PMU

NASA Astrophysics Data System (ADS)

Murthy, Ch; MIEEE; Mohanta, D. K.; SMIEE; Meher, Mahendra

2017-08-01

Continuous monitoring and control of the power system is essential for its healthy operation. This can be achieved by making the system observable as well as controllable. Many efforts have been made by several researchers to make the system observable by placing the Phasor Measurement Units (PMUs) at the optimal locations. But so far the idea of controllability with PMUs is not considered. This paper contributes how to check whether the system is controllable or not, if not then how make it controllable using a clustering approach. IEEE 14 bus system is considered to illustrate the concept of controllability.

Reconstructing galaxy histories from globular clusters.

PubMed

West, Michael J; Côté, Patrick; Marzke, Ronald O; Jordán, Andrés

2004-01-01

Nearly a century after the true nature of galaxies as distant 'island universes' was established, their origin and evolution remain great unsolved problems of modern astrophysics. One of the most promising ways to investigate galaxy formation is to study the ubiquitous globular star clusters that surround most galaxies. Globular clusters are compact groups of up to a few million stars. They generally formed early in the history of the Universe, but have survived the interactions and mergers that alter substantially their parent galaxies. Recent advances in our understanding of the globular cluster systems of the Milky Way and other galaxies point to a complex picture of galaxy genesis driven by cannibalism, collisions, bursts of star formation and other tumultuous events.

History of Chandra X-Ray Observatory

NASA Image and Video Library

2000-10-01

This most distant x-ray cluster of galaxies yet has been found by astronomers using Chandra X-ray Observatory (CXO). Approximately 10 billion light-years from Earth, the cluster 3C294 is 40 percent farther than the next most distant x-ray galaxy cluster. The existence of such a faraway cluster is important for understanding how the universe evolved. CXO's image reveals an hourglass-shaped region of x-ray emissions centered on the previously known central radio source (seen in this image as the blue central object) that extends outward for 60,000 light- years. The vast clouds of hot gas that surround such galaxies in clusters are thought to be heated by collapse toward the center of the cluster. Until CXO, x-ray telescopes have not had the needed sensitivity to identify such distant clusters of galaxies. Galaxy clusters are the largest gravitationally bound structures in the universe. The intensity of the x-rays in this CXO image of 3C294 is shown as red for low energy x-rays, green for intermediate, and blue for the most energetic x-rays. (Photo credit: NASA/loA/A. Fabian et al)

Clustering of adherence to personalised dietary recommendations and changes in healthy eating index within the Food4Me study.

PubMed

Livingstone, Katherine M; Celis-Morales, Carlos; Lara, Jose; Woolhead, Clara; O'Donovan, Clare B; Forster, Hannah; Marsaux, Cyril Fm; Macready, Anna L; Fallaize, Rosalind; Navas-Carretero, Santiago; San-Cristobal, Rodrigo; Kolossa, Silvia; Tsirigoti, Lydia; Lambrinou, Christina P; Moschonis, George; Surwiłło, Agnieszka; Drevon, Christian A; Manios, Yannis; Traczyk, Iwona; Gibney, Eileen R; Brennan, Lorraine; Walsh, Marianne C; Lovegrove, Julie A; Martinez, J Alfredo; Saris, Wim Hm; Daniel, Hannelore; Gibney, Mike; Mathers, John C

2016-12-01

To characterise clusters of individuals based on adherence to dietary recommendations and to determine whether changes in Healthy Eating Index (HEI) scores in response to a personalised nutrition (PN) intervention varied between clusters. Food4Me study participants were clustered according to whether their baseline dietary intakes met European dietary recommendations. Changes in HEI scores between baseline and month 6 were compared between clusters and stratified by whether individuals received generalised or PN advice. Pan-European, Internet-based, 6-month randomised controlled trial. Adults aged 18-79 years (n 1480). Individuals in cluster 1 (C1) met all recommended intakes except for red meat, those in cluster 2 (C2) met two recommendations, and those in cluster 3 (C3) and cluster 4 (C4) met one recommendation each. C1 had higher intakes of white fish, beans and lentils and low-fat dairy products and lower percentage energy intake from SFA (P<0·05). C2 consumed less chips and pizza and fried foods than C3 and C4 (P<0·05). C1 were lighter, had lower BMI and waist circumference than C3 and were more physically active than C4 (P<0·05). More individuals in C4 were smokers and wanted to lose weight than in C1 (P<0·05). Individuals who received PN advice in C4 reported greater improvements in HEI compared with C3 and C1 (P<0·05). The cluster where the fewest recommendations were met (C4) reported greater improvements in HEI following a 6-month trial of PN whereas there was no difference between clusters for those randomised to the Control, non-personalised dietary intervention.

Effects of improved sanitation on diarrheal reduction for children under five in Idiofa, DR Congo: a cluster randomized trial.

PubMed

Cha, Seungman; Lee, JaeEun; Seo, DongSik; Park, Byoung Mann; Mansiangi, Paul; Bernard, Kabore; Mulakub-Yazho, Guy Jerome Nkay; Famasulu, Honore Minka

2017-09-19

The lack of safe water and sanitation contributes to the rampancy of diarrhea in many developing countries. This study describes the design of a cluster-randomized trial in Idiofa, the Democratic Republic of the Congo, seeking evidence of the impact of improved sanitation on diarrhea for children under four. Of the 276 quartiers, 18 quartiers were randomly allocated to the intervention or control arm. Seven hundred and-twenty households were sampled and the youngest under-four child in each household was registered for this study. The primary endpoint of the study is diarrheal incidence, prevalence and duration in children under five. Material subsidies will be provided only to the households who complete pit digging plus superstructure and roof construction, regardless of their income level. This study employs a Sanitation Calendar so that the mother of each household can record the diarrheal episodes of her under-four child on a daily basis. The diary enables examination of the effect of the sanitation intervention on diarrhea duration and also resolves the limitation of the small number of clusters in the trial. In addition, the project will be monitored through the 'Sanitation Map', on which all households in the study area, including both the control and intervention arms, are registered. To avoid information bias or courtesy bias, photos will be taken of the latrine during the household visit, and a supervisor will determine well-equipped latrine uptake based on the photos. This reduces the possibility of recall bias and under- or over-estimation of diarrhea, which was the main limitation of previous studies. The study was approved by the Institutional Review Board of the School of Public Health, Kinshasa University (ESP/CE/040/15; April 13, 2015) and registered as an International Standard Randomized Controlled Trial (ISRCTN: 10,419,317) on March 13, 2015.

Pathways to prevention: protocol for the CAP (Climate and Preventure) study to evaluate the long-term effectiveness of school-based universal, selective and combined alcohol misuse prevention into early adulthood.

PubMed

Newton, Nicola C; Stapinski, Lexine; Slade, Tim; Champion, Katrina E; Barrett, Emma L; Chapman, Catherine; Smout, Anna; Lawler, Siobhan; Mather, Marius; Castellanos-Ryan, Natalie; Conrod, Patricia J; Teesson, Maree

2018-05-21

Alcohol use and associated harms are among the leading causes of burden of disease among young people, highlighting the need for effective prevention. The Climate and Preventure (CAP) study was the first trial of a combined universal and selective school-based approach to preventing alcohol misuse among adolescents. Initial results indicate that universal, selective and combined prevention were all effective in delaying the uptake of alcohol use and binge drinking for up to 3 years following the interventions. However, little is known about the sustainability of prevention effects across the transition to early adulthood, a period of increased exposure to alcohol and other drug use. This paper describes the protocol for the CAP long-term follow-up study which will determine the effectiveness of universal, selective and combined alcohol misuse prevention up to 7 years post intervention, and across the transition from adolescence into early adulthood. A cluster randomized controlled trial was conducted between 2012 and 2015 with 2190 students (mean age: 13.3 yrs) from 26 Australian high schools. Participants were randomized to receive one of four conditions; universal prevention for all students (Climate); selective prevention for high-risk students (Preventure); combined universal and selective prevention (Climate and Preventure; CAP); or health education as usual (Control). The positive effect of the interventions on alcohol use at 12-, 24- and 36-month post baseline have previously been reported. This study will follow up the CAP study cohort approximately 5- and 7-years post baseline. The primary outcome will be alcohol use and related harms. Secondary outcomes will be cannabis use, alcohol and other drug harms including violent behavior, and mental health symptomatology. Analyses will be conducted using multi-level, mixed effects models within an intention-to-treat framework. This study will provide the first ever evaluation of the long-term effectiveness of combining universal and selective approaches to alcohol prevention and will examine the durability of intervention effects into the longer-term, over a 7-year period from adolescence to early adulthood. This trial was registered in the Australian New Zealand Clinical Trials Registry ( ACTRN12612000026820 ) on January 6th 2012.

Towards a better understanding of the relationship between executive control and theory of mind: an intra-cultural comparison of three diverse samples.

PubMed

Shahaeian, Ameneh; Henry, Julie D; Razmjoee, Maryam; Teymoori, Ali; Wang, Cen

2015-09-01

Previous research has consistently indicated that theory of mind (ToM) is associated with executive control in the preschool years. However, interpretation of this literature is limited by the fact that most studies have focused exclusively on urbanized Western cultural samples. Consequently, it is not clear whether the association between ToM and executive control reflects the specific features of this particular cohort or instead reflects a universal pattern. The present study provides the first empirical assessment of these two constructs in three diverse groups of Iranian children. Participants were 142 preschoolers (4-5 years old) from high-socioeconomic status (SES) urban (n = 33), low-SES urban (n = 37) and rural villages (n = 77). The results show that there is a robust association between ToM and executive control in all three groups, and that executive control contributes significant unique variance to ToM understanding, even after controlling for a range of variables that have been proposed as potential confounders of this relationship. However, although the three groups were equated in ToM, significant differences in executive control were evident. Moreover, cluster analysis identified three distinct clusters that were relatively homogeneous with respect to executive control and SES. One of these clusters was characterized by both low SES and low executive functioning, and showed little evidence of ToM understanding. Taken together, these findings provide possibly the clearest evidence to date that the association between ToM and executive control is not dependent on children's previous experiences on the tasks, or their family and cultural background. © 2014 John Wiley & Sons Ltd.

An RR Lyrae period shift in terms of the Fourier parameter Phi sub 31

NASA Technical Reports Server (NTRS)

Clement, Christine M.; Jankulak, Michael; Simon, Norman R.

1992-01-01

The Fourier phase parameter Phi sub 31 has been determined for RRc stars in five globular clusters, NGC 6171, M5, M3, M53, and M15. The results indicate that the RRc stars in a given cluster show a sequence of Phi sub 31 increasing with period, and that the higher the cluster metallicity, the higher the sequence lies in a plot of Phi sub 31 with period. The Phi sub 31 values for the stars in NGC 6171 and M5 presented here are based on observations made with the University of Toronto 0.61 m telescope at Las Campanas, Chile, while those for M3, M53, and M15 are based on published data. A bootstrap procedure has been used to establish the uncertainties in the Fourier parameters. The physical significance of the relationship among Phi sub 31, period, and metallicity is not yet understood. It will need to be tested with hydrodynamic pulsation models computed with new opacities.

Monster Clusters in the Young Universe? Weak-lensing Masses of SPT-CL J0205-5829 and MOO1014+0038 with HST Observations

NASA Astrophysics Data System (ADS)

Feilx Kim, Seojin; Jee, Myungkook James

2018-01-01

Measuring High-z clusters’ masses is very important as the cluster abundance is extremely sensitive to the cosmological parameters. However, deriving their masses from the intracluster medium properties (i.e., Sunyaev-Zel’dovich or X-ray observations) is not the best method because of their departure from the hydrostatic equilibrium. Fortunately, the “See Change” Hubble Space Telescope program offers a rare opportunity to measure them using weak gravitational lensing. We study SPT-CL J0205-5829 (z=1.322) and MOO1014+0038 (z=1.24) discovered in the SPT-SZ and MaDCoW Surveys, respectively. Previous non-lensing based approaches suggest that both targets might be extremely massive clusters. After carefully addressing various possible systematics from the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) images, we successfully detect clear weak lensing signals. We present their 2-dimensional mass maps and compare our weak-lensing masses with previous ICM-based results.

Need, access, and the reach of integrated care: A typology of patients.

PubMed

Bridges, Ana J; Villalobos, Bianca T; Anastasia, Elizabeth A; Dueweke, Aubrey R; Gregus, Samantha J; Cavell, Timothy A

2017-06-01

This paper is a report on a study exploring a potential typology of primary care patients referred for integrated behavioral health care (IBHC) services. We considered whether primary care patients could be grouped into meaningful clusters based on perceived need for behavioral health services, barriers to accessing care, and past-year service utilization. We also described the development of a working partnership between our university-based research team and a federally qualified health center (FQHC). A total of 105 adult primary care patients referred for same-day behavioral health appointments completed a brief self-report questionnaire assessing past-year behavioral health concerns, service utilization, and perceived barriers to utilization. Hierarchical and k-means cluster analyses revealed 3 groups: (a) Well-Served patients, characterized by high perceived need for services, high service use, and low barriers to service use (40%); (b) Underserved patients, characterized by high perceived need, low service utilization, and high barriers to service use (20%); and (c) Subclinical patients, characterized by low perceived need, low service use, and low barriers to service use (20%). Clusters were reliably differentiated by age, primary language, insurance status, and global functioning. We found primary care patients could be grouped into 3 categories and that 60% (Underserved and Subclinical) represented groups less commonly seen in traditional mental health (MH) settings. IBHC may be a promising approach for extending the reach of MH care, and partnerships between FQHCs and university-based research teams may be a promising approach for conducting research on the IBHC service-delivery model. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Active spacecraft potential control: An ion emitter experiment. [Cluster mission

NASA Technical Reports Server (NTRS)

Riedler, W.; Goldstein, R.; Hamelin, M.; Maehlum, B. N.; Troim, J.; Olsen, R. C.; Pedersen, A.; Grard, R. J. L.; Schmidt, R.; Rudenauer, F.

1988-01-01

The cluster spacecraft are instrumented with ion emitters for charge neutralization. The emitters produce indium ions at 6 keV. The ion current is adjusted in a feedback loop with instruments measuring the spacecraft potential. The system is based on the evaporation of indium in the apex field of a needle. The design of the active spacecraft potential control instruments, and the ion emitters is presented.

NASA Finds Direct Proof of Dark Matter

NASA Astrophysics Data System (ADS)

2006-08-01

Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter. "This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Lensing Illustration Gravitational Lensing Explanation These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision. "A universe that's dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking," said Doug Clowe of the University of Arizona at Tucson, and leader of the study. "These results are direct proof that dark matter exists." Animation of Cluster Collision Animation of Cluster Collision In galaxy clusters, the normal matter, like the atoms that make up the stars, planets, and everything on Earth, is primarily in the form of hot gas and stars. The mass of the hot gas between the galaxies is far greater than the mass of the stars in all of the galaxies. This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter. Without dark matter, which is invisible and can only be detected through its gravity, the fast-moving galaxies and the hot gas would quickly fly apart. The team was granted more than 100 hours on the Chandra telescope to observe the galaxy cluster 1E0657-56. The cluster is also known as the bullet cluster, because it contains a spectacular bullet-shaped cloud of hundred-million-degree gas. The X-ray image shows the bullet shape is due to a wind produced by the high-speed collision of a smaller cluster with a larger one. 4-Panel Illustrations of Cluster Collision 4-Panel Illustrations of Cluster Collision In addition to the Chandra observation, the Hubble Space Telescope, the European Southern Observatory's Very Large Telescope and the Magellan optical telescopes were used to determine the location of the mass in the clusters. This was done by measuring the effect of gravitational lensing, where gravity from the clusters distorts light from background galaxies as predicted by Einstein's theory of general relativity. The hot gas in this collision was slowed by a drag force, similar to air resistance. In contrast, the dark matter was not slowed by the impact, because it does not interact directly with itself or the gas except through gravity. This produced the separation of the dark and normal matter seen in the data. If hot gas was the most massive component in the clusters, as proposed by alternative gravity theories, such a separation would not have been seen. Instead, dark matter is required. Animation: Galaxy Cluster in Perspective Animation: Galaxy Cluster in Perspective "This is the type of result that future theories will have to take into account," said Sean Carroll, a cosmologist at the University of Chicago, who was not involved with the study. "As we move forward to understand the true nature of dark matter, this new result will be impossible to ignore." This result also gives scientists more confidence that the Newtonian gravity familiar on Earth and in the solar system also works on the huge scales of galaxy clusters. "We've closed this loophole about gravity, and we've come closer than ever to seeing this invisible matter," Clowe said. These results are being published in an upcoming issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. Additional information and images can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Is semantic verbal fluency impairment explained by executive function deficits in schizophrenia?

PubMed

Berberian, Arthur A; Moraes, Giovanna V; Gadelha, Ary; Brietzke, Elisa; Fonseca, Ana O; Scarpato, Bruno S; Vicente, Marcella O; Seabra, Alessandra G; Bressan, Rodrigo A; Lacerda, Acioly L

2016-04-19

To investigate if verbal fluency impairment in schizophrenia reflects executive function deficits or results from degraded semantic store or inefficient search and retrieval strategies. Two groups were compared: 141 individuals with schizophrenia and 119 healthy age and education-matched controls. Both groups performed semantic and phonetic verbal fluency tasks. Performance was evaluated using three scores, based on 1) number of words generated; 2) number of clustered/related words; and 3) switching score. A fourth performance score based on the number of clusters was also measured. SZ individuals produced fewer words than controls. After controlling for the total number of words produced, a difference was observed between the groups in the number of cluster-related words generated in the semantic task. In both groups, the number of words generated in the semantic task was higher than that generated in the phonemic task, although a significant group vs. fluency type interaction showed that subjects with schizophrenia had disproportionate semantic fluency impairment. Working memory was positively associated with increased production of words within clusters and inversely correlated with switching. Semantic fluency impairment may be attributed to an inability (resulting from reduced cognitive control) to distinguish target signal from competing noise and to maintain cues for production of memory probes.

A cluster randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of classroom-based cognitive-behavioural therapy (CBT) in reducing symptoms of depression in high-risk adolescents.

PubMed

Stallard, P; Phillips, R; Montgomery, A A; Spears, M; Anderson, R; Taylor, J; Araya, R; Lewis, G; Ukoumunne, O C; Millings, A; Georgiou, L; Cook, E; Sayal, K

2013-10-01

Depression in adolescents is a significant problem that impairs everyday functioning and increases the risk of severe mental health disorders in adulthood. Although this is a major problem, relatively few adolescents with, or at risk of developing, depression are identified and referred for treatment. This suggests the need to investigate alternative approaches whereby preventative interventions are made widely available in schools. To investigate the clinical effectiveness and cost-effectiveness of classroom-based cognitive-behavioural therapy (CBT) in reducing symptoms of depression in high-risk adolescents. Cluster randomised controlled trial. Year groups ( n = 28) randomly allocated on a 1 : 1 : 1 basis to one of three trial arms once all schools were recruited and balanced for number of classes, number of students, Personal, Social and Health Education (PSHE) lesson frequency, and scheduling of PSHE. Year groups 8 to 11 (ages 12-16 years) in mixed-sex secondary schools in the UK. Data were collected between 2009 and 2011. Young people who attended PSHE at participating schools were eligible ( n = 5503). Of the 5030 who agreed to participate, 1064 (21.2%) were classified as 'high risk': 392 in the classroom-based CBT arm, 374 in the attention control PSHE arm and 298 in the usual PSHE arm. Primary outcome data on the high-risk group at 12 months were available for classroom-based CBT ( n = 296), attention control PSHE ( n = 308) and usual PSHE ( n = 242). The Resourceful Adolescent Programme (RAP) is a focused CBT-based intervention adapted for the UK (RAP-UK) and delivered by two facilitators external to the school. Control groups were usual PSHE (usual school curriculum delivered by teachers) and attention control (usual school PSHE with additional support from two facilitators). Interventions were delivered universally to whole classes. Clinical effectiveness: symptoms of depression [Short Mood and Feelings Questionnaire (SMFQ)] in adolescents at high risk of depression 12 months from baseline. Cost-effectiveness: incremental cost-effectiveness ratios (ICERs) based on SMFQ score and quality-adjusted life-years (from European Quality of Life-5 Dimensions scores) between baseline and 12 months. Process evaluation: reach, attrition and qualitative feedback from service recipients and providers. SMFQ scores had decreased for high-risk adolescents in all trial arms at 12 months, but there was no difference between arms [classroom-based CBT vs. usual PSHE adjusted difference in means 0.97, 95% confidence interval (CI) -0.34 to 2.28; classroom-based CBT vs. attention control PSHE -0.63, 95% CI -1.99 to 0.73]. Costs of interventions per child were estimated at £41.96 for classroom-based CBT and £34.45 for attention control PSHE. Fieller's method was used to obtain a parametric estimate of the 95% CI for the ICERs and construct the cost-effectiveness acceptability curve, confirming that classroom-based CBT was not cost-effective relative to the controls. Reach of classroom-based CBT was good and attrition was low (median 80% attending ≥ 60% of sessions), but feedback indicated some difficulties with acceptability and sustainability. Classroom-based CBT, attention control PSHE and usual PSHE produced similar outcomes. Classroom-based CBT may result in increased self-awareness and reporting of depressive symptoms. Classroom-based CBT was not shown to be cost-effective. While schools are a convenient way of reaching a wide range of young people, implementing classroom-based CBT within schools is challenging, particularly with regard to fitting programmes into a busy timetable, the lack of value placed on PSHE, and difficulties engaging with teachers and young people. Wider use of classroom-based depression prevention programmes should not be undertaken without further research. If universal preventative approaches are to be pursued, their clinical effectiveness and cost-effectiveness with younger children (aged 10-11 years), before the incidence of depression increases, should be investigated. Alternatively, the clinical effectiveness of indicated school-based programmes targeting those already displaying symptoms of depression should be investigated. Current Controlled Trials ISRCTN19083628. This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 17, No. 47. See the HTA programme website for further project information.

NAP SACC UK: protocol for a feasibility cluster randomised controlled trial in nurseries and at home to increase physical activity and healthy eating in children aged 2–4 years

PubMed Central

Kipping, R; Jago, R; Metcalfe, C; White, J; Papadaki, A; Campbell, R; Hollingworth, W; Ward, D; Wells, S; Brockman, R; Nicholson, A; Moore, L

2016-01-01

Introduction Systematic reviews have identified the lack of intervention studies with young children to prevent obesity. This feasibility study examines the feasibility and acceptability of adapting the Nutrition and Physical Activity Self-Assessment for Child Care (NAP SACC) intervention in the UK to inform a full-scale trial. Methods and analysis A feasibility cluster randomised controlled trial in 12 nurseries in England, with 6 randomly assigned to the adapted NAP SACC UK intervention: nursery staff will receive training and support from an NAP SACC UK Partner to review the nursery environment (nutrition, physical activity, sedentary behaviours and oral health) and set goals for making changes. Parents will be invited to participate in a digital media-based home component to set goals for making changes in the home. As this is a feasibility study, the sample size was not based on a power calculation but will indicate the likely response rates and intracluster correlations. Measures will be assessed at baseline and 8–10 months later. We will estimate the recruitment rate of nurseries and children and adherence to the intervention and data. Nursery measurements will include the Environmental Policy Assessment and Observation score and the nursery staff's review of the nursery environment. Child measurements will include height and weight to calculate z-score body mass index (zBMI), accelerometer-determined minutes of moderate-to-vigorous physical activity per day and sedentary time, and diet using the Child and Diet Evaluation Tool. Questionnaires with nursery staff and parents will measure mediators. A process evaluation will assess fidelity of intervention delivery and views of participants. Ethics and dissemination Ethical approval for this study was given by Wales 3 NHS Research Ethics Committee. Findings will be made available through publication in peer-reviewed journals, at conferences and to participants via the University of Bristol website. Data will be available from the University of Bristol Research Data Repository. Trial registration number ISRCTN16287377. PMID:27053273

NAP SACC UK: protocol for a feasibility cluster randomised controlled trial in nurseries and at home to increase physical activity and healthy eating in children aged 2-4 years.

PubMed

Kipping, R; Jago, R; Metcalfe, C; White, J; Papadaki, A; Campbell, R; Hollingworth, W; Ward, D; Wells, S; Brockman, R; Nicholson, A; Moore, L

2016-04-06

Systematic reviews have identified the lack of intervention studies with young children to prevent obesity. This feasibility study examines the feasibility and acceptability of adapting the Nutrition and Physical Activity Self-Assessment for Child Care (NAP SACC) intervention in the UK to inform a full-scale trial. A feasibility cluster randomised controlled trial in 12 nurseries in England, with 6 randomly assigned to the adapted NAP SACC UK intervention: nursery staff will receive training and support from an NAP SACC UK Partner to review the nursery environment (nutrition, physical activity, sedentary behaviours and oral health) and set goals for making changes. Parents will be invited to participate in a digital media-based home component to set goals for making changes in the home. As this is a feasibility study, the sample size was not based on a power calculation but will indicate the likely response rates and intracluster correlations. Measures will be assessed at baseline and 8-10 months later. We will estimate the recruitment rate of nurseries and children and adherence to the intervention and data. Nursery measurements will include the Environmental Policy Assessment and Observation score and the nursery staff's review of the nursery environment. Child measurements will include height and weight to calculate z-score body mass index (zBMI), accelerometer-determined minutes of moderate-to-vigorous physical activity per day and sedentary time, and diet using the Child and Diet Evaluation Tool. Questionnaires with nursery staff and parents will measure mediators. A process evaluation will assess fidelity of intervention delivery and views of participants. Ethical approval for this study was given by Wales 3 NHS Research Ethics Committee. Findings will be made available through publication in peer-reviewed journals, at conferences and to participants via the University of Bristol website. Data will be available from the University of Bristol Research Data Repository. ISRCTN16287377. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Global, local and focused geographic clustering for case-control data with residential histories

PubMed Central

Jacquez, Geoffrey M; Kaufmann, Andy; Meliker, Jaymie; Goovaerts, Pierre; AvRuskin, Gillian; Nriagu, Jerome

2005-01-01

Background This paper introduces a new approach for evaluating clustering in case-control data that accounts for residential histories. Although many statistics have been proposed for assessing local, focused and global clustering in health outcomes, few, if any, exist for evaluating clusters when individuals are mobile. Methods Local, global and focused tests for residential histories are developed based on sets of matrices of nearest neighbor relationships that reflect the changing topology of cases and controls. Exposure traces are defined that account for the latency between exposure and disease manifestation, and that use exposure windows whose duration may vary. Several of the methods so derived are applied to evaluate clustering of residential histories in a case-control study of bladder cancer in south eastern Michigan. These data are still being collected and the analysis is conducted for demonstration purposes only. Results Statistically significant clustering of residential histories of cases was found but is likely due to delayed reporting of cases by one of the hospitals participating in the study. Conclusion Data with residential histories are preferable when causative exposures and disease latencies occur on a long enough time span that human mobility matters. To analyze such data, methods are needed that take residential histories into account. PMID:15784151

DMINDA: an integrated web server for DNA motif identification and analyses.

PubMed

Ma, Qin; Zhang, Hanyuan; Mao, Xizeng; Zhou, Chuan; Liu, Bingqiang; Chen, Xin; Xu, Ying

2014-07-01

DMINDA (DNA motif identification and analyses) is an integrated web server for DNA motif identification and analyses, which is accessible at http://csbl.bmb.uga.edu/DMINDA/. This web site is freely available to all users and there is no login requirement. This server provides a suite of cis-regulatory motif analysis functions on DNA sequences, which are important to elucidation of the mechanisms of transcriptional regulation: (i) de novo motif finding for a given set of promoter sequences along with statistical scores for the predicted motifs derived based on information extracted from a control set, (ii) scanning motif instances of a query motif in provided genomic sequences, (iii) motif comparison and clustering of identified motifs, and (iv) co-occurrence analyses of query motifs in given promoter sequences. The server is powered by a backend computer cluster with over 150 computing nodes, and is particularly useful for motif prediction and analyses in prokaryotic genomes. We believe that DMINDA, as a new and comprehensive web server for cis-regulatory motif finding and analyses, will benefit the genomic research community in general and prokaryotic genome researchers in particular. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Network cosmology.

PubMed

Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S; Rideout, David; Meyer, David; Boguñá, Marián

2012-01-01

Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology.

Network Cosmology

PubMed Central

Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S.; Rideout, David; Meyer, David; Boguñá, Marián

2012-01-01

Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology. PMID:23162688

Short-term effects of the "Together at School" intervention program on children's socio-emotional skills: a cluster randomized controlled trial.

PubMed

Kiviruusu, Olli; Björklund, Katja; Koskinen, Hanna-Leena; Liski, Antti; Lindblom, Jallu; Kuoppamäki, Heini; Alasuvanto, Paula; Ojala, Tiina; Samposalo, Hanna; Harmes, Nina; Hemminki, Elina; Punamäki, Raija-Leena; Sund, Reijo; Santalahti, Päivi

2016-05-26

Together at School is a universal intervention program designed to promote socio-emotional skills among primary-school children. It is based on a whole school approach, and implemented in school classes by teachers. The aim of the present study is to examine the short-term effects of the intervention program in improving socio-emotional skills and reducing psychological problems among boys and girls. We also examine whether these effects depend on grade level (Grades 1 to 3) and intervention dosage. This cluster randomized controlled trial design included 79 Finnish primary schools (40 intervention and 39 control) with 3 704 children. The outcome measures were the Strengths and Difficulties Questionnaire (SDQ) and the Multisource Assessment of Social Competence Scale (MASCS) with teachers as raters. The intervention dosage was indicated by the frequencies six central tools were used by the teachers. The data was collected at baseline and 6 months later. Intervention effects were analyzed using multilevel modeling. When analyzed across all grades no intervention effect was observed in improving children's socio-emotional skills or in reducing their psychological problems at 6-month follow-up. Among third (compared to first) graders the intervention decreased psychological problems. Stratified analyses by gender showed that this effect was significant only among boys and that among them the intervention also improved third graders' cooperation skills. Among girls the intervention effects were not moderated by grade. Implementing the intervention with intended intensity (i.e. a high enough dosage) had a significant positive effect on cooperation skills. When analyzed separately among genders, this effect was significant only in girls. These first, short-term results of the Together at School intervention program did not show any main effects on children's socio-emotional skills or psychological problems. This lack of effects may be due to the relatively short follow-up period given the universal, whole school-based approach of the program. The results suggest that the grade level where the intervention is started might be a factor in the program's effectiveness. Moreover, the results also suggest that for this type of intervention program to be effective, it needs to be delivered with a high enough dosage. ClinicalTrials.gov identifier: NCT02178332 ; Date of registration: 03-April-2014.

Cluster size statistic and cluster mass statistic: two novel methods for identifying changes in functional connectivity between groups or conditions.

PubMed

Ing, Alex; Schwarzbauer, Christian

2014-01-01

Functional connectivity has become an increasingly important area of research in recent years. At a typical spatial resolution, approximately 300 million connections link each voxel in the brain with every other. This pattern of connectivity is known as the functional connectome. Connectivity is often compared between experimental groups and conditions. Standard methods used to control the type 1 error rate are likely to be insensitive when comparisons are carried out across the whole connectome, due to the huge number of statistical tests involved. To address this problem, two new cluster based methods--the cluster size statistic (CSS) and cluster mass statistic (CMS)--are introduced to control the family wise error rate across all connectivity values. These methods operate within a statistical framework similar to the cluster based methods used in conventional task based fMRI. Both methods are data driven, permutation based and require minimal statistical assumptions. Here, the performance of each procedure is evaluated in a receiver operator characteristic (ROC) analysis, utilising a simulated dataset. The relative sensitivity of each method is also tested on real data: BOLD (blood oxygen level dependent) fMRI scans were carried out on twelve subjects under normal conditions and during the hypercapnic state (induced through the inhalation of 6% CO2 in 21% O2 and 73%N2). Both CSS and CMS detected significant changes in connectivity between normal and hypercapnic states. A family wise error correction carried out at the individual connection level exhibited no significant changes in connectivity.

Defining functional SMA and pre-SMA subregions in human MFC using resting state fMRI: functional connectivity-based parcellation method.

PubMed

Kim, Jae-Hun; Lee, Jong-Min; Jo, Hang Joon; Kim, Sook Hui; Lee, Jung Hee; Kim, Sung Tae; Seo, Sang Won; Cox, Robert W; Na, Duk L; Kim, Sun I; Saad, Ziad S

2010-02-01

Noninvasive parcellation of the human cerebral cortex is an important goal for understanding and examining brain functions. Recently, the patterns of anatomical connections using diffusion tensor imaging (DTI) have been used to parcellate brain regions. Here, we present a noninvasive parcellation approach that uses "functional fingerprints" obtained by correlation measures on resting state functional magnetic resonance imaging (fMRI) data to parcellate brain regions. In other terms, brain regions are parcellated based on the similarity of their connection--as reflected by correlation during resting state--to the whole brain. The proposed method was used to parcellate the medial frontal cortex (MFC) into supplementary motor areas (SMA) and pre-SMA subregions. In agreement with anatomical landmark-based parcellation, we find that functional fingerprint clustering of the MFC results in anterior and posterior clusters. The probabilistic maps from 12 subjects showed that the anterior cluster is mainly located rostral to the vertical commissure anterior (VCA) line, whereas the posterior cluster is mainly located caudal to VCA line, suggesting the homologues of pre-SMA and SMA. The functional connections from the putative pre-SMA cluster were connected to brain regions which are responsible for complex/cognitive motor control, whereas those from the putative SMA cluster were connected to brain regions which are related to the simple motor control. These findings demonstrate the feasibility of the functional connectivity-based parcellation of the human cerebral cortex using resting state fMRI. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Cluster Size Statistic and Cluster Mass Statistic: Two Novel Methods for Identifying Changes in Functional Connectivity Between Groups or Conditions

PubMed Central

Ing, Alex; Schwarzbauer, Christian

2014-01-01

Functional connectivity has become an increasingly important area of research in recent years. At a typical spatial resolution, approximately 300 million connections link each voxel in the brain with every other. This pattern of connectivity is known as the functional connectome. Connectivity is often compared between experimental groups and conditions. Standard methods used to control the type 1 error rate are likely to be insensitive when comparisons are carried out across the whole connectome, due to the huge number of statistical tests involved. To address this problem, two new cluster based methods – the cluster size statistic (CSS) and cluster mass statistic (CMS) – are introduced to control the family wise error rate across all connectivity values. These methods operate within a statistical framework similar to the cluster based methods used in conventional task based fMRI. Both methods are data driven, permutation based and require minimal statistical assumptions. Here, the performance of each procedure is evaluated in a receiver operator characteristic (ROC) analysis, utilising a simulated dataset. The relative sensitivity of each method is also tested on real data: BOLD (blood oxygen level dependent) fMRI scans were carried out on twelve subjects under normal conditions and during the hypercapnic state (induced through the inhalation of 6% CO2 in 21% O2 and 73%N2). Both CSS and CMS detected significant changes in connectivity between normal and hypercapnic states. A family wise error correction carried out at the individual connection level exhibited no significant changes in connectivity. PMID:24906136

The structure and environment of young stellar clusters in spiral galaxies

NASA Astrophysics Data System (ADS)

Larsen, S. S.

2004-03-01

A search for stellar clusters has been carried out in 18 nearby spiral galaxies, using archive images from the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. All of the galaxies have previously been imaged from the ground in UBVI. A catalogue of structural parameters, photometry and comments based on visual inspection of the clusters is compiled and used to investigate correlations between cluster structure, environment, age and mass. Least-squares fits to the data suggest correlations between both the full-width at half-maximum (FWHM) and half-light radius (Reff) of the clusters and their masses (M) at about the 3σ level. Although both relations show a large scatter, the fits have substantially shallower slopes than for a constant-density relation (size ∝ M1/3). However, many of the youngest clusters have extended halos which make the Reff determinations uncertain. There is no evidence for galaxy-to-galaxy variations in the mean cluster sizes. In particular, the mean sizes do not appear to depend on the host galaxy star formation rate surface density. Many of the youngest objects (age < 107 years) are located in strongly crowded regions, and about 1/3-1/2 of them are double or multiple sources. The HST images are also used to check the nature of cluster candidates identified in a previous ground-based survey. The contamination rate in the ground-based sample is generally less than about 20%, but some cluster identifications remain ambiguous because of crowding even with HST imaging, especially for the youngest objects. Full Tables \\ref{tab:all}-\\ref{tab:hstphot}, and \\ref{tab:gb} are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/416/537 Based on observations obtained with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

The effectiveness of a clinically integrated e-learning course in evidence-based medicine: a cluster randomised controlled trial.

PubMed

Kulier, Regina; Coppus, Sjors F P J; Zamora, Javier; Hadley, Julie; Malick, Sadia; Das, Kausik; Weinbrenner, Susanne; Meyerrose, Berrit; Decsi, Tamas; Horvath, Andrea R; Nagy, Eva; Emparanza, Jose I; Arvanitis, Theodoros N; Burls, Amanda; Cabello, Juan B; Kaczor, Marcin; Zanrei, Gianni; Pierer, Karen; Stawiarz, Katarzyna; Kunz, Regina; Mol, Ben W J; Khan, Khalid S

2009-05-12

To evaluate the educational effects of a clinically integrated e-learning course for teaching basic evidence-based medicine (EBM) among postgraduates compared to a traditional lecture-based course of equivalent content. We conducted a cluster randomised controlled trial in the Netherlands and the UK involving postgraduate trainees in six obstetrics and gynaecology departments. Outcomes (knowledge gain and change in attitude towards EBM) were compared between the clinically integrated e-learning course (intervention) and the traditional lecture based course (control). We measured change from pre- to post-intervention scores using a validated questionnaire assessing knowledge (primary outcome) and attitudes (secondary outcome). There were six clusters involving teaching of 61 postgraduate trainees (28 in the intervention and 33 in the control group). The intervention group achieved slightly higher scores for knowledge gain compared to the control, but these results were not statistically significant (difference in knowledge gain: 3.5 points, 95% CI -2.7 to 9.8, p = 0.27). The attitudinal changes were similar for both groups. A clinically integrated e-learning course was at least as effective as a traditional lecture based course and was well accepted. Being less costly than traditional teaching and allowing for more independent learning through materials that can be easily updated, there is a place for incorporating e-learning into postgraduate EBM curricula that offer on-the-job training for just-in-time learning. ACTRN12609000022268.

Lattice animals in diffusion limited binary colloidal system

NASA Astrophysics Data System (ADS)

Shireen, Zakiya; Babu, Sujin B.

2017-08-01

In a soft matter system, controlling the structure of the amorphous materials has been a key challenge. In this work, we have modeled irreversible diffusion limited cluster aggregation of binary colloids, which serves as a model for chemical gels. Irreversible aggregation of binary colloidal particles leads to the formation of a percolating cluster of one species or both species which are also called bigels. Before the formation of the percolating cluster, the system forms a self-similar structure defined by a fractal dimension. For a one component system when the volume fraction is very small, the clusters are far apart from each other and the system has a fractal dimension of 1.8. Contrary to this, we will show that for the binary system, we observe the presence of lattice animals which has a fractal dimension of 2 irrespective of the volume fraction. When the clusters start inter-penetrating, we observe a fractal dimension of 2.5, which is the same as in the case of the one component system. We were also able to predict the formation of bigels using a simple inequality relation. We have also shown that the growth of clusters follows the kinetic equations introduced by Smoluchowski for diffusion limited cluster aggregation. We will also show that the chemical distance of a cluster in the flocculation regime will follow the same scaling law as predicted for the lattice animals. Further, we will also show that irreversible binary aggregation comes under the universality class of the percolation theory.

Effects of quality improvement in health facilities and community mobilization through women's groups on maternal, neonatal and perinatal mortality in three districts of Malawi: MaiKhanda, a cluster randomized controlled effectiveness trial.

PubMed

Colbourn, Tim; Nambiar, Bejoy; Bondo, Austin; Makwenda, Charles; Tsetekani, Eric; Makonda-Ridley, Agnes; Msukwa, Martin; Barker, Pierre; Kotagal, Uma; Williams, Cassie; Davies, Ros; Webb, Dale; Flatman, Dorothy; Lewycka, Sonia; Rosato, Mikey; Kachale, Fannie; Mwansambo, Charles; Costello, Anthony

2013-09-01

Maternal, perinatal and neonatal mortality remains high in low-income countries. We evaluated community and facility-based interventions to reduce deaths in three districts of Malawi. We evaluated a rural participatory women's group community intervention (CI) and a quality improvement intervention at health centres (FI) via a two-by-two factorial cluster randomized controlled trial. Consenting pregnant women were followed-up to 2 months after birth using key informants. Primary outcomes were maternal, perinatal and neonatal mortality. Clusters were health centre catchment areas assigned using stratified computer-generated randomization. Following exclusions, including non-birthing facilities, 61 clusters were analysed: control (17 clusters, 4912 births), FI (15, 5335), CI (15, 5080) and FI + CI (14, 5249). This trial was registered as International Standard Randomised Controlled Trial [ISRCTN18073903]. Outcomes for 14,576 and 20,576 births were recorded during baseline (June 2007-September 2008) and intervention (October 2008-December 2010) periods. For control, FI, CI and FI + CI clusters neonatal mortality rates were 34.0, 28.3, 29.9 and 27.0 neonatal deaths per 1000 live births and perinatal mortality rates were 56.2, 55.1, 48.0 and 48.4 per 1000 births, during the intervention period. Adjusting for clustering and stratification, the neonatal mortality rate was 22% lower in FI + CI than control clusters (OR = 0.78, 95% CI 0.60-1.01), and the perinatal mortality rate was 16% lower in CI clusters (OR = 0.84, 95% CI 0.72-0.97). We did not observe any intervention effects on maternal mortality. Despite implementation problems, a combined community and facility approach using participatory women's groups and quality improvement at health centres reduced newborn mortality in rural Malawi.

Effects of quality improvement in health facilities and community mobilization through women’s groups on maternal, neonatal and perinatal mortality in three districts of Malawi: MaiKhanda, a cluster randomized controlled effectiveness trial

PubMed Central

Colbourn, Tim; Nambiar, Bejoy; Bondo, Austin; Makwenda, Charles; Tsetekani, Eric; Makonda-Ridley, Agnes; Msukwa, Martin; Barker, Pierre; Kotagal, Uma; Williams, Cassie; Davies, Ros; Webb, Dale; Flatman, Dorothy; Lewycka, Sonia; Rosato, Mikey; Kachale, Fannie; Mwansambo, Charles; Costello, Anthony

2016-01-01

Background Maternal, perinatal and neonatal mortality remains high in low-income countries. We evaluated community and facility-based interventions to reduce deaths in three districts of Malawi. Methods We evaluated a rural participatory women’s group community intervention (CI) and a quality improvement intervention at health centres (FI) via a two-by-two factorial cluster randomized controlled trial. Consenting pregnant women were followed-up to 2 months after birth using key informants. Primary outcomes were maternal, perinatal and neonatal mortality. Clusters were health centre catchment areas assigned using stratified computer-generated randomization. Following exclusions, including non-birthing facilities, 61 clusters were analysed: control (17 clusters, 4912 births), FI (15, 5335), CI (15, 5080) and FI + CI (14, 5249). This trial was registered as International Standard Randomised Controlled Trial [ISRCTN18073903]. Outcomes for 14 576 and 20 576 births were recorded during baseline (June 2007–September 2008) and intervention (October 2008–December 2010) periods. Results For control, FI, CI and FI + CI clusters neonatal mortality rates were 34.0, 28.3, 29.9 and 27.0 neonatal deaths per 1000 live births and perinatal mortality rates were 56.2, 55.1, 48.0 and 48.4 per 1000 births, during the intervention period. Adjusting for clustering and stratification, the neonatal mortality rate was 22% lower in FI + CI than control clusters (OR = 0.78, 95% CI 0.60–1.01), and the perinatal mortality rate was 16% lower in CI clusters (OR = 0.84, 95% CI 0.72–0.97). We did not observe any intervention effects on maternal mortality. Conclusions Despite implementation problems, a combined community and facility approach using participatory women’s groups and quality improvement at health centres reduced newborn mortality in rural Malawi. PMID:24030269

Associated factors with attention deficit hyperactivity disorder (ADHD): a case-control study.

PubMed

Malek, Ayyoub; Amiri, Shahrokh; Sadegfard, Majid; Abdi, Salman; Amini, Saeedeh

2012-09-01

The current study attempted to investigate factors associated with attention deficit hyperactivity disorder (ADHD) in children without co-morbidities. In this case-control study, 164 ADHD children who attended the Child and Adolescent Psychiatric Clinics of Tabriz University of Medical Sciences, Iran were compared with 166 normal children selected in a random-cluster method from primary and secondary schools. Clinical interviews based on DSM-IV-TR using K-SADS were used to diagnose ADHD cases and to select the control group. Participants were matched for age. We used chi-square and binary logistic regression for data analysis. Among the associated factors with ADHD were gender and maternal employment. Boys (OR 0.54; 95% confidence interval: 0.34 - 0.86) and those children with working mothers (OR 0.16: 95% confidence interval: 0.06 - 0.86) suffered more from ADHD. The birth season, family size, birth order, and parental kinship were not among risk factors for ADHD. The results of the study show that maternal employment and male gender are among the associated risk factors for ADHD.

Satisfaction Clustering Analysis of Distance Education Computer Programming Students: A Sample of Karadeniz Technical University

ERIC Educational Resources Information Center

Ozyurt, Hacer

2014-01-01

In line with recently developing technology, distant education systems based on information technologies are started to be commonly used within higher education. Students' satisfaction is one of the vital aspects in order to maintain distant education efficiently and achieving its goal. As a matter of the fact, previous studies proved that student…

Date Fighting Experiences among College Students: Are They Associated with Other Health-Risk Behaviors?

ERIC Educational Resources Information Center

DuRant, Robert; Champion, Heather; Wolfson, Mark; Omli, Morrow; McCoy, Thomas; D'Agostino, Ralph B., Jr.; Wagoner, Kim; Mitra, Ananda

2007-01-01

Objective: The authors examined the clustering of health-risk behaviors among college students who reported date fight involvement. Participants and Methods: The authors administered a Web-based survey to a stratified random sample of 3,920 college students from 10 universities in North Carolina. Results: Among men, 5.6% reported date fight…

The effect of an intervention to break the gender bias habit for faculty at one institution: a cluster randomized, controlled trial.

PubMed

Carnes, Molly; Devine, Patricia G; Baier Manwell, Linda; Byars-Winston, Angela; Fine, Eve; Ford, Cecilia E; Forscher, Patrick; Isaac, Carol; Kaatz, Anna; Magua, Wairimu; Palta, Mari; Sheridan, Jennifer

2015-02-01

Despite sincere commitment to egalitarian, meritocratic principles, subtle gender bias persists, constraining women's opportunities for academic advancement. The authors implemented a pair-matched, single-blind, cluster randomized, controlled study of a gender-bias-habit-changing intervention at a large public university. Participants were faculty in 92 departments or divisions at the University of Wisconsin-Madison. Between September 2010 and March 2012, experimental departments were offered a gender-bias-habit-changing intervention as a 2.5-hour workshop. Surveys measured gender bias awareness; motivation, self-efficacy, and outcome expectations to reduce bias; and gender equity action. A timed word categorization task measured implicit gender/leadership bias. Faculty completed a work-life survey before and after all experimental departments received the intervention. Control departments were offered workshops after data were collected. Linear mixed-effects models showed significantly greater changes post intervention for faculty in experimental versus control departments on several outcome measures, including self-efficacy to engage in gender-equity-promoting behaviors (P = .013). When ≥ 25% of a department's faculty attended the workshop (26 of 46 departments), significant increases in self-reported action to promote gender equity occurred at three months (P = .007). Post intervention, faculty in experimental departments expressed greater perceptions of fit (P = .024), valuing of their research (P = .019), and comfort in raising personal and professional conflicts (P = .025). An intervention that facilitates intentional behavioral change can help faculty break the gender bias habit and change department climate in ways that should support the career advancement of women in academic medicine, science, and engineering.

A cluster randomized controlled trial to assess the effectiveness of an intervention to educate students about depression.

PubMed

Merritt, Rowena K; Price, Jonathan R; Mollison, Jill; Geddes, John R

2007-03-01

Depression is an important cause of disability worldwide, with many people experiencing their first depressive episode before the age of 18. University students are particularly vulnerable to depression. Depression can be treated successfully in most patients. However, for treatment to be successful, depressed people need to recognize their symptoms as illness, present to medical care, and be aware that effective treatment is available. A thoughtful health campaign might therefore increase the likelihood of successful treatment. A cluster randomized controlled trial was conducted to determine the effectiveness of an educational intervention. A total of 3313 undergraduate students participated in the study. The intervention consisted of postcards and posters on depression and its treatment. The primary outcome was student awareness that depression can be treated effectively. Secondary outcomes included the proportion of students reading the postcards, recognition of symptoms and knowledge of treatments. The postcards were read by 69% of students. Less than half of participants reported that depression could be treated effectively, and there was no evidence of a difference between the intervention and control groups [341 (49.1%) v. 379 (49.7%), difference -0.7, p=0.8, 95% confidence interval (CI) -5.1 to 3.7]. However, intervention group participants were more likely than control group participants to recognize depressive symptoms and to report that antidepressants are not addictive. Many university students lack knowledge about depression and its treatment. Simple and cheap media, such as postcards and posters, might help to improve awareness in areas where current knowledge is low.

A BARYONIC EFFECT ON THE MERGER TIMESCALE OF GALAXY CLUSTERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Congyao; Yu, Qingjuan; Lu, Youjun, E-mail: yuqj@pku.edu.cn

2016-04-01

Accurate estimation of the merger timescales of galaxy clusters is important for understanding the cluster merger process and further understanding the formation and evolution of the large-scale structure of the universe. In this paper, we explore a baryonic effect on the merger timescale of galaxy clusters by using hydrodynamical simulations. We find that the baryons play an important role in accelerating the merger process. The merger timescale decreases upon increasing the gas fraction of galaxy clusters. For example, the merger timescale is shortened by a factor of up to 3 for merging clusters with gas fractions of 0.15, compared withmore » the timescale obtained with 0 gas fractions. The baryonic effect is significant for a wide range of merger parameters and is particularly more significant for nearly head-on mergers and high merging velocities. The baryonic effect on the merger timescale of galaxy clusters is expected to have an impact on the structure formation in the universe, such as the cluster mass function and massive substructures in galaxy clusters, and a bias of “no-gas” may exist in the results obtained from the dark matter-only cosmological simulations.« less

Agent-based method for distributed clustering of textual information

DOEpatents

Potok, Thomas E [Oak Ridge, TN; Reed, Joel W [Knoxville, TN; Elmore, Mark T [Oak Ridge, TN; Treadwell, Jim N [Louisville, TN

2010-09-28

A computer method and system for storing, retrieving and displaying information has a multiplexing agent (20) that calculates a new document vector (25) for a new document (21) to be added to the system and transmits the new document vector (25) to master cluster agents (22) and cluster agents (23) for evaluation. These agents (22, 23) perform the evaluation and return values upstream to the multiplexing agent (20) based on the similarity of the document to documents stored under their control. The multiplexing agent (20) then sends the document (21) and the document vector (25) to the master cluster agent (22), which then forwards it to a cluster agent (23) or creates a new cluster agent (23) to manage the document (21). The system also searches for stored documents according to a search query having at least one term and identifying the documents found in the search, and displays the documents in a clustering display (80) of similarity so as to indicate similarity of the documents to each other.

Non-thermal emission and dynamical state of massive galaxy clusters from CLASH sample

NASA Astrophysics Data System (ADS)

Pandey-Pommier, M.; Richard, J.; Combes, F.; Edge, A.; Guiderdoni, B.; Narasimha, D.; Bagchi, J.; Jacob, J.

2016-12-01

Massive galaxy clusters are the most violent large scale structures undergoing merger events in the Universe. Based upon their morphological properties in X-rays, they are classified as un-relaxed and relaxed clusters and often host (a fraction of them) different types of non-thermal radio emitting components, viz., 'haloes', 'mini-haloes', 'relics' and 'phoenix' within their Intra Cluster Medium (ICM). The radio haloes show steep (α = -1.2) and ultra steep (α < -1.5) spectral properties at low radio frequencies, giving important insights on the merger (pre or post) state of the cluster. Ultra steep spectrum radio halo emissions are rare and expected to be the dominating population to be discovered via LOFAR and SKA in the future. Further, the distribution of matter (morphological information), alignment of hot X-ray emitting gas from the ICM with the total mass (dark + baryonic matter) and the bright cluster galaxy (BCG) is generally used to study the dynamical state of the cluster. We present here a multi wavelength study on 14 massive clusters from the CLASH survey and show the correlation between the state of their merger in X-ray and spectral properties (1.4 GHz - 150 MHz) at radio wavelengths. Using the optical data we also discuss about the gas-mass alignment, in order to understand the interplay between dark and baryonic matter in massive galaxy clusters.

Finding approximate gene clusters with Gecko 3.

PubMed

Winter, Sascha; Jahn, Katharina; Wehner, Stefanie; Kuchenbecker, Leon; Marz, Manja; Stoye, Jens; Böcker, Sebastian

2016-11-16

Gene-order-based comparison of multiple genomes provides signals for functional analysis of genes and the evolutionary process of genome organization. Gene clusters are regions of co-localized genes on genomes of different species. The rapid increase in sequenced genomes necessitates bioinformatics tools for finding gene clusters in hundreds of genomes. Existing tools are often restricted to few (in many cases, only two) genomes, and often make restrictive assumptions such as short perfect conservation, conserved gene order or monophyletic gene clusters. We present Gecko 3, an open-source software for finding gene clusters in hundreds of bacterial genomes, that comes with an easy-to-use graphical user interface. The underlying gene cluster model is intuitive, can cope with low degrees of conservation as well as misannotations and is complemented by a sound statistical evaluation. To evaluate the biological benefit of Gecko 3 and to exemplify our method, we search for gene clusters in a dataset of 678 bacterial genomes using Synechocystis sp. PCC 6803 as a reference. We confirm detected gene clusters reviewing the literature and comparing them to a database of operons; we detect two novel clusters, which were confirmed by publicly available experimental RNA-Seq data. The computational analysis is carried out on a laptop computer in <40 min. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Discovery of a Large-Scale Filament Connected to the Massive Galaxy Cluster MACS J0717.5+3745 at z=0.551,

NASA Astrophysics Data System (ADS)

Ebeling, H.; Barrett, E.; Donovan, D.

2004-07-01

We report the detection of a 4 h-170 Mpc long large-scale filament leading into the massive galaxy cluster MACS J0717.5+3745. The extent of this object well beyond the cluster's nominal virial radius (~2.3 Mpc) rules out prior interaction between its constituent galaxies and the cluster and makes it a prime candidate for a genuine filament as opposed to a merger remnant or a double cluster. The structure was discovered as a pronounced overdensity of galaxies selected to have V-R colors close to the cluster red sequence. Extensive spectroscopic follow-up of over 300 of these galaxies in a region covering the filament and the cluster confirms that the entire structure is located at the cluster redshift of z=0.545. Featuring galaxy surface densities of typically 15 Mpc-2 down to luminosities of 0.13L*V, the most diffuse parts of the filament are comparable in density to the clumps of red galaxies found around A851 in the only similar study carried out to date (Kodama et al.). Our direct detection of an extended large-scale filament funneling matter onto a massive distant cluster provides a superb target for in-depth studies of the evolution of galaxies in environments of greatly varying density and supports the predictions from theoretical models and numerical simulations of structure formation in a hierarchical picture. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W. M. Keck Foundation. Based partly on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (US), the Particle Physics and Astronomy Research Council (UK), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNP (Brazil), and CONICET (Argentina).

Personalized drug discovery: HCA approach optimized for rare diseases at Tel Aviv University.

PubMed

Solmesky, Leonardo J; Weil, Miguel

2014-03-01

The Cell screening facility for personalized medicine (CSFPM) at Tel Aviv University in Israel is devoted to screening small molecules libraries for finding new drugs for rare diseases using human cell based models. The main strategy of the facility is based on smartly reducing the size of the compounds collection in similarity clusters and at the same time keeping high diversity of pharmacophores. This strategy allows parallel screening of several patient derived - cells in a personalized screening approach. The tested compounds are repositioned drugs derived from collections of phase III and FDA approved small molecules. In addition, the facility carries screenings using other chemical libraries and toxicological characterizations of nanomaterials.

Personalized Medicine in Veterans with Traumatic Brain Injuries

DTIC Science & Technology

2014-07-01

9 control cases are subjected to unsupervised hierarchical clustering analysis using the UPGMA algorithm with cosine correlation as the similarity...in unsu- pervised hierarchical clustering by the Un- weighted Pair-Group Method using Arithmetic averages ( UPGMA ) based on cosine correlation of row...of log2 trans- formed MAS5.0 signal values; probe set cluster- ing was performed by the UPGMA method using Cosine correlation as the similarity

A Lyapunov Function Based Remedial Action Screening Tool Using Real-Time Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitra, Joydeep; Ben-Idris, Mohammed; Faruque, Omar

This report summarizes the outcome of a research project that comprised the development of a Lyapunov function based remedial action screening tool using real-time data (L-RAS). The L-RAS is an advanced computational tool that is intended to assist system operators in making real-time redispatch decisions to preserve power grid stability. The tool relies on screening contingencies using a homotopy method based on Lyapunov functions to avoid, to the extent possible, the use of time domain simulations. This enables transient stability evaluation at real-time speed without the use of massively parallel computational resources. The project combined the following components. 1. Developmentmore » of a methodology for contingency screening using a homotopy method based on Lyapunov functions and real-time data. 2. Development of a methodology for recommending remedial actions based on the screening results. 3. Development of a visualization and operator interaction interface. 4. Testing of screening tool, validation of control actions, and demonstration of project outcomes on a representative real system simulated on a Real-Time Digital Simulator (RTDS) cluster. The project was led by Michigan State University (MSU), where the theoretical models including homotopy-based screening, trajectory correction using real-time data, and remedial action were developed and implemented in the form of research-grade software. Los Alamos National Laboratory (LANL) contributed to the development of energy margin sensitivity dynamics, which constituted a part of the remedial action portfolio. Florida State University (FSU) and Southern California Edison (SCE) developed a model of the SCE system that was implemented on FSU's RTDS cluster to simulate real-time data that was streamed over the internet to MSU where the L-RAS tool was executed and remedial actions were communicated back to FSU to execute stabilizing controls on the simulated system. LCG Consulting developed the visualization and operator interaction interface, based on specifications provided by MSU. The project was performed from October 2012 to December 2016, at the end of which the L-RAS tool, as described above, was completed and demonstrated. The project resulted in the following innovations and contributions: (a) the L-RAS software prototype, tested on a simulated system, vetted by utility personnel, and potentially ready for wider testing and commercialization; (b) an RTDS-based test bed that can be used for future research in the field; (c) a suite of breakthrough theoretical contributions to the field of power system stability and control; and (d) a new tool for visualization of power system stability margins. While detailed descriptions of the development and implementation of the various project components have been provided in the quarterly reports, this final report provides an overview of the complete project, and is demonstrated using public domain test systems commonly used in the literature. The SCE system, and demonstrations thereon, are not included in this report due to Critical Energy Infrastructure Information (CEII) restrictions.« less

Universal Infantry Weapons Trainer (UIWT). Volume 1. M-16 Rifle Model.

DTIC Science & Technology

1980-07-01

id entityb bloc moo") The Universal Infantry Weapons Trainer (UIWT) is an electro-optic based , micro- computer controlled, training device that...CLASIIClATSON OF THIS PAOt(la., Diat Eaeied) t SUMMARY The Universal Infantry Weapon Trainer (UIWT), is an electro-optic based , microcomputer controlled...Routine Flowchart .... ................ .. 52 111-36 Fixed Base FIFO Operation ...... ................. 54 111-37 Moving Base FIFO Operation

Toward the 21st Century: Preparing Proactive Visionary Transformational Leaders for Building Learning Communities. Human Resource Development. Tampa Cluster. Winter 1994.

ERIC Educational Resources Information Center

Groff, Warren H.

This document describes the Tampa Cluster human resources development (HRD) seminar that was conducted as part of Nova University's distance education program in higher education (PHE). Discussed first are HRD in the agricultural and business industrial eras and changing HRD practices/needs, Nova University's PHE and HRD program, the proceedings…

A study to evaluate the acceptability, feasibility and impact of packaged interventions ("Diarrhea Pack") for prevention and treatment of childhood diarrhea in rural Pakistan.

PubMed

Habib, Muhammad Atif; Soofi, Sajid; Sadiq, Kamran; Samejo, Tariq; Hussain, Musawar; Mirani, Mushtaq; Rehmatullah, Asmatullah; Ahmed, Imran; Bhutta, Zulfiqar A

2013-10-03

Diarrhea remains one of the leading public health issues in developing countries and is a major contributor in morbidity and mortality in children under five years of age. Interventions such as ORS, Zinc, water purification and improved hygiene and sanitation can significantly reduce the diarrhea burden but their coverage remains low and has not been tested as packaged intervention before. This study attempts to evaluate the package of evidence based interventions in a "Diarrhea Pack" through first level health care providers at domiciliary level in community based settings. This study sought to evaluate the acceptability, feasibility and impact of diarrhea Pack on diarrhea burden. A cluster randomized design was used to evaluate the objectives of the project a union council was considered as a cluster for analysis, a total of eight clusters, four in intervention and four in control were included in the study. We conducted a baseline survey in all clusters followed by the delivery of diarrhea Pack in intervention clusters through community health workers at domiciliary level and through sales promoters to health care providers and pharmacies. Four quarterly surveillance rounds were conducted to evaluate the impact of diarrhea pack in all clusters by an independent team of Field workers. Both the intervention and control clusters were similar at the baseline but as the study progress we found a significant increase in uptake of ORS and Zinc along with the reduction in antibiotic use, diarrhea burden and hospitalization in intervention clusters when compared with the control clusters. We found that the Diarrhea Pack was well accepted with all of its components in the community. The intervention was well accepted and had a productive impact on the uptake of ORS and zinc and reduction in the use of antibiotics. It is feasible to deliver interventions such as diarrhea pack through community health workers in community settings. The intervention has the potential to be scaled up at national level.

Probing high-redshift clusters with HST/ACS gravitational weak-lensing and Chandra x-ray observations

NASA Astrophysics Data System (ADS)

Jee, Myungkook James

2006-06-01

Clusters of galaxies, the largest gravitationally bound objects in the Universe, are useful tracers of cosmic evolution, and particularly detailed studies of still-forming clusters at high-redshifts can considerably enhance our understanding of the structure formation. We use two powerful methods that have become recently available for the study of these distant clusters: spaced- based gravitational weak-lensing and high-resolution X-ray observations. Detailed analyses of five high-redshift (0.8 < z < 1.3) clusters are presented based on the deep Advanced Camera for Surveys (ACS) and Chandra X-ray images. We show that, when the instrumental characteristics are properly understood, the newly installed ACS on the Hubble Space Telescope (HST) can detect subtle shape distortions of background galaxies down to the limiting magnitudes of the observations, which enables the mapping of the cluster dark matter in unprecedented high-resolution. The cluster masses derived from this HST /ACS weak-lensing study have been compared with those from the re-analyses of the archival Chandra X-ray data. We find that there are interesting offsets between the cluster galaxy, intracluster medium (ICM), and dark matter centroids, and possible scenarios are discussed. If the offset is confirmed to be uniquitous in other clusters, the explanation may necessitate major refinements in our current understanding of the nature of dark matter, as well as the cluster galaxy dynamics. CL0848+4452, the highest-redshift ( z = 1.27) cluster yet detected in weak-lensing, has a significant discrepancy between the weak- lensing and X-ray masses. If this trend is found to be severe and common also for other X-ray weak clusters at redshifts beyond the unity, the conventional X-ray determination of cluster mass functions, often inferred from their immediate X-ray properties such as the X-ray luminosity and temperature via the so-called mass-luminosity (M-L) and mass-temperature (M-T) relations, will become highly unstable in this redshift regime. Therefore, the relatively unbiased weak-lensing measurements of the cluster mass properties can be used to adequately calibrate the scaling relations in future high-redshift cluster investigations.

Classification of posture maintenance data with fuzzy clustering algorithms

NASA Technical Reports Server (NTRS)

Bezdek, James C.

1992-01-01

Sensory inputs from the visual, vestibular, and proprioreceptive systems are integrated by the central nervous system to maintain postural equilibrium. Sustained exposure to microgravity causes neurosensory adaptation during spaceflight, which results in decreased postural stability until readaptation occurs upon return to the terrestrial environment. Data which simulate sensory inputs under various sensory organization test (SOT) conditions were collected in conjunction with Johnson Space Center postural control studies using a tilt-translation device (TTD). The University of West Florida applied the fuzzy c-meams (FCM) clustering algorithms to this data with a view towards identifying various states and stages of subjects experiencing such changes. Feature analysis, time step analysis, pooling data, response of the subjects, and the algorithms used are discussed.

The cavernous sinus in cluster headache - a quantitative structural magnetic resonance imaging study.

PubMed

Arkink, Enrico B; Schoonman, Guus G; van Vliet, Jorine A; Bakels, Hannah S; Sneeboer, Marjolein Am; Haan, Joost; van Buchem, Mark A; Ferrari, Michel D; Kruit, Mark C

2017-03-01

Background It has been hypothesized that a constitutionally narrow cavernous sinus might predispose individuals to cluster headache. Cavernous sinus dimensions, however, have never been assessed. Methods In this case-control study, we measured the dimensions of the cavernous sinus, skull base, internal carotid and pituitary gland with high-resolution T2-weighted magnetic resonance imaging in 25 episodic, 24 chronic and 13 probable cluster headache patients, 8 chronic paroxysmal hemicrania patients and 22 headache-free controls. Dimensions were compared between groups, correcting for age, sex and transcranial diameter. Results On qualitative inspection, no relevant pathology or anatomic variants that were previously associated with cluster headache or chronic paroxysmal hemicranias were observed in the cavernous sinus or paracavernous structures. The left-to-right transcranial diameter at the temporal fossa level (mean ± SD) was larger in the headache groups (episodic cluster headache: 147.5 ± 7.3 mm, p = 0.044; chronic cluster headache: 150.2 ± 7.3 mm, p < 0.001; probable cluster headache: 146.0 ± 5.3 mm, p = 0.012; and chronic paroxysmal hemicrania: 145.2 ± 9.4 mm, p = 0.044) compared with controls (140.2 ± 8.0 mm). After adjusting for transcranial diameter and correcting for multiple comparisons, there were no differences in the dimensions of the cavernous sinus and surrounding structures between headache patients and controls. Conclusion Patients with cluster headache or chronic paroxysmal hemicrania had wider skulls than headache-free controls, but the proportional dimensions of the cavernous sinus were similar.

A Multi-wavelength Mass Analysis of RCS2 J232727.6-020437, A ˜3 × 1015 M⊙ Galaxy Cluster at z = 0.7

NASA Astrophysics Data System (ADS)

Sharon, K.; Gladders, M. D.; Marrone, D. P.; Hoekstra, H.; Rasia, E.; Bourdin, H.; Gifford, D.; Hicks, A. K.; Greer, C.; Mroczkowski, T.; Barrientos, L. F.; Bayliss, M.; Carlstrom, J. E.; Gilbank, D. G.; Gralla, M.; Hlavacek-Larrondo, J.; Leitch, E.; Mazzotta, P.; Miller, C.; Muchovej, S. J. C.; Schrabback, T.; Yee, H. K. C.; RCS-Team

2015-11-01

We present an initial study of the mass and evolutionary state of a massive and distant cluster, RCS2 J232727.6-020437. This cluster, at z = 0.6986, is the richest cluster discovered in the RCS2 project. The mass measurements presented in this paper are derived from all possible mass proxies: X-ray measurements, weak-lensing shear, strong lensing, Sunyaev-Zel’dovich effect decrement, the velocity distribution of cluster member galaxies, and galaxy richness. While each of these observables probe the mass of the cluster at a different radius, they all indicate that RCS2 J232727.6-020437 is among the most massive clusters at this redshift, with an estimated mass of {M}200˜ 3× {10}15{h}70-1 {M}⊙ . In this paper, we demonstrate that the various observables are all reasonably consistent with each other to within their uncertainties. RCS2 J232727.6-020437 appears to be well relaxed—with circular and concentric X-ray isophotes, with a cool core, and no indication of significant substructure in extensive galaxy velocity data. Based on observations obtained with : MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; the NASA/ESA Hubble Space Telescope (HST), obtained from the data archive at the Space Telescope Institute. STScI is operated by the association of Universities for Research in Astronomy, Inc. under the NASA contract NAS 5-2655; the 6.5 m Magellan telescopes located at Las Campanas Observatory, Chile;

Improving adolescent mental health and resilience through a resilience-based intervention in schools: study protocol for a randomised controlled trial.

PubMed

Dray, Julia; Bowman, Jenny; Freund, Megan; Campbell, Elizabeth; Wolfenden, Luke; Hodder, Rebecca K; Wiggers, John

2014-07-18

Research investigating the effectiveness of universal interventions to reduce the risk of mental health problems remains limited. Schools are a promising setting within which adolescents can receive interventions aimed at promoting their mental health. The aim of this study is to assess the effectiveness of a resilience-based prevention-focused intervention in reducing the risk of mental health problems among adolescents attending secondary school in socio-economically disadvantaged areas. A cluster randomised control trial will be conducted, with schools as the unit of randomisation. Initially, 32 secondary schools will be randomly allocated to a control or intervention group (12 control and 20 intervention). An intervention focused on improving student internal and external resilience factors will be implemented in intervention schools. A survey of students in Grade 7 in both intervention and control schools will be conducted (baseline) and repeated three years later when the students are in Grade 10. The Strengths and Difficulties Questionnaire will be used to measure the risk of mental health problems. At follow-up, the risk of mental health problems will be compared between Grade 10 students in intervention and control schools to determine intervention effectiveness. The study presents an opportunity to determine the effectiveness of a comprehensive resilience-based intervention in reducing the risk of mental health problems in adolescents attending secondary schools. The outcomes of the trial are of importance to youth, schools, mental health clinicians and policymakers. Australian New Zealand Clinical Trials Registry, ACTRN12611000606987, registered 14 June 2011.

Improving adolescent mental health and resilience through a resilience-based intervention in schools: study protocol for a randomised controlled trial

PubMed Central

2014-01-01

Background Research investigating the effectiveness of universal interventions to reduce the risk of mental health problems remains limited. Schools are a promising setting within which adolescents can receive interventions aimed at promoting their mental health. The aim of this study is to assess the effectiveness of a resilience-based prevention-focused intervention in reducing the risk of mental health problems among adolescents attending secondary school in socio-economically disadvantaged areas. Methods/design A cluster randomised control trial will be conducted, with schools as the unit of randomisation. Initially, 32 secondary schools will be randomly allocated to a control or intervention group (12 control and 20 intervention). An intervention focused on improving student internal and external resilience factors will be implemented in intervention schools. A survey of students in Grade 7 in both intervention and control schools will be conducted (baseline) and repeated three years later when the students are in Grade 10. The Strengths and Difficulties Questionnaire will be used to measure the risk of mental health problems. At follow-up, the risk of mental health problems will be compared between Grade 10 students in intervention and control schools to determine intervention effectiveness. Discussion The study presents an opportunity to determine the effectiveness of a comprehensive resilience-based intervention in reducing the risk of mental health problems in adolescents attending secondary schools. The outcomes of the trial are of importance to youth, schools, mental health clinicians and policymakers. Trial registration Australian New Zealand Clinical Trials Registry, ACTRN12611000606987, registered 14 June 2011. PMID:25037455

Regulation of the X-ray luminosity of clusters of galaxies by cooling and supernova feedback.

PubMed

Voit, G M; Bryan, G L

2001-11-22

Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of a cluster, and the baryons confined by this potential radiate X-rays with a luminosity that depends mainly on the gas density in the cluster's core. Predictions of the X-rays' properties based on models of cluster formation do not, however, agree with the observations. If the models ignore the condensation of cooling gas into stars and feedback from the associated supernovae, they overestimate the X-ray luminosity because the density of the core gas is too high. An early episode of uniformly distributed supernova feedback could rectify this by heating the uncondensed gas and therefore making it harder to compress into the core, but such a process seems to require an implausibly large number of supernovae. Here we show how radiative cooling of intergalactic gas and subsequent supernova heating conspire to eliminate highly compressible low-entropy gas from the intracluster medium. This brings the core entropy and X-ray luminosities of clusters into agreement with the observations, in a way that depends little on the efficiency of supernova heating in the early Universe.

Evaluation of Primary Immunization Coverage of Infants Under Universal Immunization Programme in an Urban Area of Bangalore City Using Cluster Sampling and Lot Quality Assurance Sampling Techniques

PubMed Central

K, Punith; K, Lalitha; G, Suman; BS, Pradeep; Kumar K, Jayanth

2008-01-01

Research Question: Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? Objective: To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Study Design: Population-based cross-sectional study. Study Setting: Areas under Mathikere Urban Health Center. Study Subjects: Children aged 12 months to 23 months. Sample Size: 220 in cluster sampling, 76 in lot quality assurance sampling. Statistical Analysis: Percentages and Proportions, Chi square Test. Results: (1) Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2) Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area. PMID:19876474

Effectiveness of an e-learning course in evidence-based medicine for foundation (internship) training.

PubMed

Hadley, Julie; Kulier, Regina; Zamora, Javier; Coppus, Sjors F P J; Weinbrenner, Susanne; Meyerrose, Berrit; Decsi, Tamas; Horvath, Andrea R; Nagy, Eva; Emparanza, Jose I; Arvanitis, Theodoros N; Burls, Amanda; Cabello, Juan B; Kaczor, Marcin; Zanrei, Gianni; Pierer, Karen; Kunz, Regina; Wilkie, Veronica; Wall, David; Mol, Ben Wj; Khan, Khalid S

2010-07-01

To evaluate the educational effectiveness of a clinically integrated e-learning course for teaching basic evidence-based medicine (EBM) among postgraduate medical trainees compared to a traditional lecture-based course of equivalent content. We conducted a cluster randomized controlled trial to compare a clinically integrated e-learning EBM course (intervention) to a lecture-based course (control) among postgraduate trainees at foundation or internship level in seven teaching hospitals in the UK West Midlands region. Knowledge gain among participants was measured with a validated instrument using multiple choice questions. Change in knowledge was compared between groups taking into account the cluster design and adjusted for covariates at baseline using generalized estimating equations (GEE) model. There were seven clusters involving teaching of 237 trainees (122 in the intervention and 115 in the control group). The total number of postgraduate trainees who completed the course was 88 in the intervention group and 72 in the control group. After adjusting for baseline knowledge, there was no difference in the amount of improvement in knowledge of EBM between the two groups. The adjusted post course difference between the intervention group and the control group was only 0.1 scoring points (95% CI -1.2-1.4). An e-learning course in EBM was as effective in improving knowledge as a standard lecture-based course. The benefits of an e-learning approach need to be considered when planning EBM curricula as it allows standardization of teaching materials and is a potential cost-effective alternative to standard lecture-based teaching.

Impacts of regional transport on black carbon in Huairou, Beijing, China.

PubMed

Wang, Yuqin; de Foy, Benjamin; Schauer, James J; Olson, Michael R; Zhang, Yang; Li, Zhengqiang; Zhang, Yuanxun

2017-02-01

The 22 nd Asia-Pacific Economic Cooperation (APEC) Conference was held near Yanqi Lake, Huairou, in Beijing, China during November 10-11, 2014. To guarantee haze-free days during the APEC Conference, the Beijing government and the governments of the surrounding provinces implemented a series of controls. Three months of Aethalometer 880 nm black carbon (BC) measurements were examined to understand the hourly fluctuations in BC concentrations that resulted from emission controls and meteorology changes. Measurements were collected at the University of Chinese Academy of Sciences near the APEC Conference site and in Central Beijing at the Institute of Remote Sensing and Digital Earth of the Chinese Academy of Sciences. Synoptic conditions are successfully represented through analysis of backward trajectories in six cluster groups. The clusters are identified based on air mass transport from various areas such as Inner Mongolia, Russia, three northeastern provinces, and Hebei industrial areas, to the measurement sites. Air pollution control measures during the APEC Conference significantly reduced BC at the conference site (Huairou) and in Central Beijing, with greater reductions in BC concentrations at the conference site than in Central Beijing. The highest BC concentrations in Huairou were associated with air masses originating from Central Beijing rather than from the Hebei industrial region. The success of the control measures implemented in Beijing and the surrounding regions demonstrates that BC concentrations can be effectively reduced to protect human health and mitigate regional climate forcing. This study also demonstrates the need for regional strategies to reduce BC concentrations, since urban areas like Beijing are sources as well as downwind receptors of emissions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reducing disability in community-dwelling frail older people: cost-effectiveness study alongside a cluster randomised controlled trial.

PubMed

Metzelthin, Silke F; van Rossum, Erik; Hendriks, Marike R C; De Witte, Luc P; Hobma, Sjoerd O; Sipers, Walther; Kempen, Gertrudis I J M

2015-05-01

although proactive primary care, including early detection and treatment of community-dwelling frail older people, is a part of the national healthcare policy in several countries, little is known about its cost-effectiveness. to evaluate the cost-effectiveness of a proactive primary care approach in community-dwelling frail older people. embedded in a cluster randomised trial among 12 Dutch general practitioner practices, an economic evaluation was performed from a societal perspective with a time horizon of 24 months. frail older people in the intervention group received an in-home assessment and interdisciplinary care based on a tailor-made treatment plan and regular evaluation and follow-up. Practices in the control group delivered usual care. The primary outcome for the cost-effectiveness and cost-utility analysis was disability and health-related quality of life, respectively. multilevel analyses among 346 frail older people showed no significant differences between the groups regarding disability and health-related quality of life at 24 months. People in the intervention group used, as expected, more primary care services, but there was no decline in more expensive hospital and long-term care. Total costs over 24 months tended to be higher in the intervention group than in the control group (€26,503 versus €20,550, P = 0.08). the intervention under study led to an increase in healthcare utilisation and related costs without providing any beneficial effects. This study adds to the scarce amount of evidence of the cost-effectiveness of proactive primary care in community-dwelling frail older people. Current Controlled Trials, ISRCTN 31954692. © The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Evolution of the cluster optical galaxy luminosity function in the CFHTLS: breaking the degeneracy between mass and redshift

NASA Astrophysics Data System (ADS)

Sarron, F.; Martinet, N.; Durret, F.; Adami, C.

2018-06-01

Obtaining large samples of galaxy clusters is important for cosmology: cluster counts as a function of redshift and mass can constrain the parameters of our Universe. They are also useful in order to understand the formation and evolution of clusters. We develop an improved version of the Adami & MAzure Cluster FInder (AMACFI), now the Adami, MAzure & Sarron Cluster FInder (AMASCFI), and apply it to the 154 deg2 of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) to obtain a large catalogue of 1371 cluster candidates with mass M200 > 1014 M⊙ and redshift z ≤ 0.7. We derive the selection function of the algorithm from the Millennium simulation, and cluster masses from a richness-mass scaling relation built from matching our candidates with X-ray detections. We study the evolution of these clusters with mass and redshift by computing the i'-band galaxy luminosity functions (GLFs) for the early-type (ETGs) and late-type galaxies (LTGs). This sample is 90% pure and 70% complete, and therefore our results are representative of a large fraction of the cluster population in these redshift and mass ranges. We find an increase in both the ETG and LTG faint populations with decreasing redshift (with Schechter slopes αETG = -0.65 ± 0.03 and αLTG = -0.95 ± 0.04 at z = 0.6, and αETG = -0.79 ± 0.02 and αLTG = -1.26 ± 0.03 at z = 0.2) and also a decrease in the LTG (but not the ETG) bright end. Our large sample allows us to break the degeneracy between mass and redshift, finding that the redshift evolution is more pronounced in high-mass clusters, but that there is no significant dependence of the faint end on mass for a given redshift. These results show that the cluster red sequence is mainly formed at redshift z > 0.7, and that faint ETGs continue to enrich the red sequence through quenching of brighter LTGs at z ≤ 0.7. The efficiency of this quenching is higher in large-mass clusters, while the accretion rate of faint LTGs is lower as the more massive clusters have already emptied most of their environment at higher redshifts. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/IRFU, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at Terapix available at the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS.The candidate cluster catalog is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/613/A67

Gate sequence for continuous variable one-way quantum computation

PubMed Central

Su, Xiaolong; Hao, Shuhong; Deng, Xiaowei; Ma, Lingyu; Wang, Meihong; Jia, Xiaojun; Xie, Changde; Peng, Kunchi

2013-01-01

Measurement-based one-way quantum computation using cluster states as resources provides an efficient model to perform computation and information processing of quantum codes. Arbitrary Gaussian quantum computation can be implemented sufficiently by long single-mode and two-mode gate sequences. However, continuous variable gate sequences have not been realized so far due to an absence of cluster states larger than four submodes. Here we present the first continuous variable gate sequence consisting of a single-mode squeezing gate and a two-mode controlled-phase gate based on a six-mode cluster state. The quantum property of this gate sequence is confirmed by the fidelities and the quantum entanglement of two output modes, which depend on both the squeezing and controlled-phase gates. The experiment demonstrates the feasibility of implementing Gaussian quantum computation by means of accessible gate sequences.

STAR CLUSTERS BORN IN THE WRECKAGE OF COSMIC COLLISIONS

NASA Technical Reports Server (NTRS)

2002-01-01

This close-up view of Stephan's Quintet, a group of five galaxies, reveals a string of bright star clusters that sparkles like a diamond necklace. The clusters, each harboring up to millions of stars, were born from the violent interactions between some members of the group. The rude encounters also have distorted the galaxies' shapes, creating elongated spiral arms and long, gaseous streamers. The NASA Hubble Space Telescope photo showcases three regions of star birth: the long, sweeping tail and spiral arms of NGC 7319 [near center]; the gaseous debris of two galaxies, NGC 7318B and NGC 7318A [top right]; and the area north of those galaxies, dubbed the northern starburst region [top left]. The clusters' bluish color indicates that they're relatively young. Their ages span from about 2 million to more than 1 billion years old. The brilliant star clusters in NGC 7318B's spiral arm (about 30,000 light-years long) and the northern starburst region are between 2 million and more than 100 million years old. NGC 7318B instigated the starburst by barreling through the region. The bully galaxy is just below NGC 7318A at top right. Although NGC 7318B appears dangerously close to NGC 7318A, it's traveling too fast to merge with its close neighbor. The partial galaxy on the far right is NGC 7320, a foreground galaxy not physically bound to the other galaxies in the picture. About 20 to 50 of the clusters in the northern starburst region reside far from the coziness of galaxies. The clusters were born about 150,000 light-years from the nearest galaxy. A galaxy that is no longer part of the group triggered another collision that wreaked havoc. NGC 7320C [not in the photo] plowed through the quintet several hundred million years ago, pulling out the 100,000 light-year-long tail of gaseous debris from NGC 7319. The clusters in NGC 7319's streaming tail are 10 million to 500 million years old and may have formed at the time of the violent collision. The faint bluish object at the tip of the tail is a young dwarf galaxy, which formed in the gaseous debris. The quintet is in the constellation Pegasus, 270 million light-years from Earth. Spied by Edouard M. Stephan in 1877, Stephan's Quintet is the first compact group ever discovered. The mosaic picture was taken by Hubble's Wide Field and Planetary Camera 2 on Dec. 30, 1998 and June 17, 1999. Image credits: NASA, Jayanne English (University of Manitoba), Sally Hunsberger (Pennsylvania State University), Zolt Levay (Space Telescope Science Institute), Sarah Gallagher (Pennsylvania State University), and Jane Charlton (Pennsylvania State University) Science credits: Sarah Gallagher (Pennsylvania State University), Jane Charlton (Pennsylvania State University), Sally Hunsberger (Pennsylvania State University), Dennis Zaritsky (University of Arizona), and Bradley Whitmore (Space Telescope Science Institute)

HUBBLE SPACE TELESCOPE ON TRACK FOR MEASURING THE EXPANSION RATE OF THE UNIVERSE

NASA Technical Reports Server (NTRS)

2002-01-01

Two international teams of astronomers, using NASA's Hubble Space Telescope, are reporting major progress in converging on an accurate measurement of the Universe's rate of expansion -- a value which has been debated for over half a century. These new results yield ranges for the age of the Universe from 9-12 billion years, and 11-14 billion years, respectively. The goal of the project is to measure the Hubble Constant to ten percent accuracy. The Hubble Space Telescope Key Project team, an international group of over 20 astronomers, is led by Wendy Freedman of Carnegie Observatories, Pasadena, CA, Robert Kennicutt, University of Arizona, Tucson, AZ, and Jeremy Mould, Mount Stromlo and Siding Springs Observatory, Australia. The group's interim results, announced at a meeting held at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, are consistent with their preliminary result, announced in 1994, of 80 kilometers per second per megaparsec (km/sec/Mpc), based on observations of a galaxy in the Virgo cluster. 'We have five different ways of measuring the Hubble Constant with HST,' said Dr. Freedman. 'The results are coming in between 68 and 78 km/sec/Mpc.' (For example, at an expansion rate of 75 km/sec/Mpc, galaxies appear to be receding from us at a rate of 162,000 miles per hour for every 3.26 million light-years farther out we look). Two months ago, a second team, led by Allan Sandage, also of the Carnegie Observatories, Abhijit Saha, STScI, Gustav Tammann and Lukas Labhardt, Astronomical Institute, University of Basel, Duccio Macchetto and Nino Panagia, STScI/European Space Agency, reported a slower expansion rate of 57 km/sec/Mpc. The value of the Hubble Constant allows astronomers to calculate the expansion age of the Universe, the time elapsed since the Big Bang. Astronomers have been arguing recently whether the time since the Big Bang is consistent with the ages of the oldest stars. The ages are calculated from combining the expansion rate with an estimate of how much matter is in space. The younger age values from each team assume the Universe is at a critical density where it contains just enough matter to expand indefinitely. The higher age estimates are calculated based on a low density of matter in space. (See 'Science Background' for more information on the expanding Universe.) 'A point of great interest is whether the age of the Universe arrived at this way is really older than the independently derived ages of the oldest stars,' said Saha, an investigator on both Hubble teams. 'The numbers lean on the side that the stellar ages are a little lower, or that the hypothesis that we live in a critical density universe needs to be questioned,' said Saha. 'As further results accumulate over the next few years, we hope to tighten the constraints on these issues.' THE OBSERVATIONS The Key Project team is midway along in their three-year program to derive the expansion rate of the Universe based on precise distance measurements to galaxies. They have now measured Cepheid distances to a dozen galaxies, and are about halfway through their overall program. The Key Project team also presented a preliminary estimate of the distance to the Fornax cluster of galaxies. The estimate was obtained through the detection and measurement with the Hubble Space Telescope of pulsating stars known as Cepheid variables found in the Fornax cluster. The Fornax cluster is measured to be approximately as far away as the Virgo cluster of galaxies -- about 60 million light-years. The Key Project team member who led this effort, Caltech astronomer Barry Madore said, 'This cluster allows us to make independent estimates of the expansion rate of the Universe using a number of different techniques. All of these methods are now in excellent agreement. With Fornax we are now at turning point in this field.' The team is measuring Cepheid distances to the Virgo and Fornax clusters of galaxies as a complementary test. Their strategy is to compare and contrast expansion numbers from a variety of distance indicators. The Key Project team is systematically looking into a variety of methods for measuring distances. They are using Cepheids in a large sample to tie into five or six 'secondary methods'. One such secondary method relates the total luminosity of a galaxy to the rate at which the galaxy is spinning, the Tully-Fisher relation. Another secondary method makes use of a special class of exploding star known as a type Ia supernova. This phase of the Hubble Constant research will be completed within another two years. In contrast, the Sandage team focused on a single secondary distance indicator, one of the same indicators also used by the Key Project team, the type Ia supernova. Sandage maintains that these stars are 'standard bombs' according to theory. He suggests that when they explode they all reach exactly the same intrinsic brightness. This would make them extremely reliable 'standard candles,' (objects with a well-known intrinsic brightness) visible 1,000 times farther away than Cepheids. Since they are intrinsically brighter than any other standard candle, they offer the opportunity for an accurate measurement of the Universe's overall expansion by looking out the farthest. Although both teams are still in disagreement over the precise rate at which the Universe is expanding and on how old it is, they are optimistic that their estimates will continue to converge with further observations and analysis. * * * * Members of the Key Project team include W. Freedman (Carnegie Observatories), R. Kennicutt (University of Arizona), J. Mould (Mount Stromlo and Siding Springs Observatories, Australia), L. Ferrarese (Johns Hopkins University), H. Ford (Johns Hopkins University), J. Graham (Department of Terrestrial Magnetism), M. Han (University of Wisconsin), P. Harding (University of Arizona), J. Hoessel (University of Wisconsin), J. Huchra (Smithsonian/Harvard University), S. Hughes (Royal Greenwich Observatory, Cambridge), G. Illingworth (University of California, Santa Cruz), B.F. Madore (IPAC/Caltech), R. Phelps (Carnegie Observatories), A. Saha (Space Telescope Science Institute), N. Silbermann (IPAC), P. Stetson (Dominion Astrophysical Observatory), and S. Sakai (IPAC). Members of the Sandage team include A. Sandage (Carnegie Observatories), A. Saha (Space Telescope Science Institute), G.A. Tammann, and L. Labhardt (Astronomical Institute, University of Basel), F.D. Macchetto and N. Panagia (Space Telescope Science Institute/European Space Agency).

Cluster headache in women: relation with menstruation, use of oral contraceptives, pregnancy, and menopause

PubMed Central

van Vliet, J A; Favier, I; Helmerhorst, F M; Haan, J; Ferrari, M D

2006-01-01

In contrast with migraine, little is known about the relation between cluster headache and menstrual cycle, oral contraceptives, pregnancy, and menopause. A population based questionnaire study was performed among 224 female cluster headache patients, and the possible effect of hormonal influences on cluster headache attacks studied. For control data, a similar but adjusted questionnaire was sent to healthy volunteers and migraine patients. It was found that menstruation, use of oral contraceptives, pregnancy, and menopause had a much smaller influence on cluster headache attacks than in migraine. Cluster headache can, however, have a large impact on individual women, for example to refrain from having children. PMID:16407458

Patterns of multiple health risk-behaviours in university students and their association with mental health: application of latent class analysis.

PubMed

Kwan, M Y; Arbour-Nicitopoulos, K P; Duku, E; Faulkner, G

2016-08-01

University and college campuses may be the last setting where it is possible to comprehensively address the health of a large proportion of the young adult population. It is important that health promoters understand the collective challenges students are facing, and to better understand the broader lifestyle behavioural patterning evident during this life stage. The purpose of this study was to examine the clustering of modifiable health-risk behaviours and to explore the relationship between these identified clusters and mental health outcomes among a large Canadian university sample. Undergraduate students (n = 837; mean age = 21 years) from the University of Toronto completed the National College Health Assessment survey. The survey consists of approximately 300 items, including assessments of student health status, mental health and health-risk behaviours. Latent class analysis was used to identify patterning based on eight salient health-risk behaviours (marijuana use, other illicit drug use, risky sex, smoking, binge drinking, poor diet, physical inactivity, and insufficient sleep). A three-class model based on student behavioural patterns emerged: "typical," "high-risk" and "moderately healthy." Results also found high-risk students reporting significantly higher levels of stress than typical students (χ2(1671) = 7.26, p < .01). Students with the highest likelihood of engaging in multiple health-risk behaviours reported poorer mental health, particularly as it relates to stress. Although these findings should be interpreted with caution due to the 28% response rate, they do suggest that interventions targeting specific student groups with similar patterning of multiple health-risk behaviours may be needed.

Geographical Analysis of the Distribution and Spread of Human Rabies in China from 2005 to 2011

PubMed Central

Yin, Wenwu; Yu, Hongjie; Si, Yali; Li, Jianhui; Zhou, Yuanchun; Zhou, Xiaoyan; Magalhães, Ricardo J. Soares.

2013-01-01

Background Rabies is a significant public health problem in China in that it records the second highest case incidence globally. Surveillance data on canine rabies in China is lacking and human rabies notifications can be a useful indicator of areas where animal and human rabies control could be integrated. Previous spatial epidemiological studies lacked adequate spatial resolution to inform targeted rabies control decisions. We aimed to describe the spatiotemporal distribution of human rabies and model its geographical spread to provide an evidence base to inform future integrated rabies control strategies in China. Methods We geo-referenced a total of 17,760 human rabies cases of China from 2005 to 2011. In our spatial analyses we used Gaussian kernel density analysis, average nearest neighbor distance, Spatial Temporal Density-Based Spatial Clustering of Applications with Noise and developed a model of rabies spatiotemporal spread. Findings Human rabies cases increased from 2005 to 2007 and decreased during 2008 to 2011 companying change of the spatial distribution. The ANN distance among human rabies cases increased between 2005 and 2011, and the degree of clustering of human rabies cases decreased during that period. A total 480 clusters were detected by ST-DBSCAN, 89.4% clusters initiated before 2007. Most of clusters were mainly found in South of China. The number and duration of cluster decreased significantly after 2008. Areas with the highest density of human rabies cases varied spatially each year and in some areas remained with high outbreak density for several years. Though few places have recovered from human rabies, most of affected places are still suffering from the disease. Conclusion Human rabies in mainland China is geographically clustered and its spatial extent changed during 2005 to 2011. The results provide a scientific basis for public health authorities in China to improve human rabies control and prevention program. PMID:23991098

Data-driven process decomposition and robust online distributed modelling for large-scale processes

NASA Astrophysics Data System (ADS)

Shu, Zhang; Lijuan, Li; Lijuan, Yao; Shipin, Yang; Tao, Zou

2018-02-01

With the increasing attention of networked control, system decomposition and distributed models show significant importance in the implementation of model-based control strategy. In this paper, a data-driven system decomposition and online distributed subsystem modelling algorithm was proposed for large-scale chemical processes. The key controlled variables are first partitioned by affinity propagation clustering algorithm into several clusters. Each cluster can be regarded as a subsystem. Then the inputs of each subsystem are selected by offline canonical correlation analysis between all process variables and its controlled variables. Process decomposition is then realised after the screening of input and output variables. When the system decomposition is finished, the online subsystem modelling can be carried out by recursively block-wise renewing the samples. The proposed algorithm was applied in the Tennessee Eastman process and the validity was verified.

Signatures of primordial black hole dark matter

NASA Astrophysics Data System (ADS)

Belotsky, K. M.; Dmitriev, A. E.; Esipova, E. A.; Gani, V. A.; Grobov, A. V.; Khlopov, M. Yu.; Kirillov, A. A.; Rubin, S. G.; Svadkovsky, I. V.

2014-11-01

The nonbaryonic dark matter of the Universe is assumed to consist of new stable forms of matter. Their stability reflects symmetry of micro-world and mechanisms of its symmetry breaking. In the early Universe heavy metastable particles can dominate, leaving primordial black holes (PBHs) after their decay, as well as the structure of particle symmetry breaking gives rise to cosmological phase transitions, from which massive black holes (BHs) and/or their clusters can originate. PBHs can be formed in such transitions within a narrow interval of masses about 1017g and, avoiding severe observational constraints on PBHs, can be a candidate for the dominant form of dark matter. PBHs in this range of mass can give solution of the problem of reionization in the Universe at the redshift z 5-10. Clusters of massive PBHs can serve as a nonlinear seeds for galaxy formation, while PBHs evaporating in such clusters can provide an interesting interpretation for the observations of point-like gamma-ray sources. Analysis of possible PBH signatures represents a universal probe for super-high energy physics in the early Universe in studies of indirect effects of the dark matter.

Westerlund 1: monolithic formation of a starburst cluster

NASA Astrophysics Data System (ADS)

Negueruela, Ignacio; Clark, J. Simon; Ritchie, Ben; Goodwin, Simon

2015-08-01

Westerlund 1 is in all likelihood the most massive young cluster in the Milky Way, with a mass on the order of 105 Msol. We have been observing its massive star population for ten years, measuring radial velocity changes for a substantial fraction of its OB stars and evolved supergiants. The properties of the evolved population are entirely consisting with a single burst of star formation, in excellent agreement with the results of studies based on the lower-mass population.Here we will present two new studies of the cluster: 1) A direct measurement of its average radial velocity and velocity dispersion based on individual measurements for several dozen stars with constant radial velocity and 2) A search for massive stars in its immediate neighbourhood using multi-object spectroscopy.The results of these two studies show that Westerlund 1 is decidedly subvirial and has a systemic radial velocity significantly different from that of nearby gas, which was assumed to provide a dynamical distance by previous authors. Moreover, the dynamical distance is inconsistent with the properties of the high-mass stellar population. In addition, we find that the cluster is completely isolated, with hardly any massive star in its vicinity that could be associated in terms of distance modulus or radial velocity. The cluster halo does not extend much further than five parsec away from the centre. All these properties are very unusual among starburst clusters in the Local Universe, which tend to form in the context of large star-forming regions.Westerlund 1 is thus the best example we have of a starburst cluster formed monolithically.

Cluster analysis of spontaneous preterm birth phenotypes identifies potential associations among preterm birth mechanisms

PubMed Central

Esplin, M Sean; Manuck, Tracy A.; Varner, Michael W.; Christensen, Bryce; Biggio, Joseph; Bukowski, Radek; Parry, Samuel; Zhang, Heping; Huang, Hao; Andrews, William; Saade, George; Sadovsky, Yoel; Reddy, Uma M.; Ilekis, John

2015-01-01

Objective We sought to employ an innovative tool based on common biological pathways to identify specific phenotypes among women with spontaneous preterm birth (SPTB), in order to enhance investigators' ability to identify to highlight common mechanisms and underlying genetic factors responsible for SPTB. Study Design A secondary analysis of a prospective case-control multicenter study of SPTB. All cases delivered a preterm singleton at SPTB ≤34.0 weeks gestation. Each woman was assessed for the presence of underlying SPTB etiologies. A hierarchical cluster analysis was used to identify groups of women with homogeneous phenotypic profiles. One of the phenotypic clusters was selected for candidate gene association analysis using VEGAS software. Results 1028 women with SPTB were assigned phenotypes. Hierarchical clustering of the phenotypes revealed five major clusters. Cluster 1 (N=445) was characterized by maternal stress, cluster 2 (N=294) by premature membrane rupture, cluster 3 (N=120) by familial factors, and cluster 4 (N=63) by maternal comorbidities. Cluster 5 (N=106) was multifactorial, characterized by infection (INF), decidual hemorrhage (DH) and placental dysfunction (PD). These three phenotypes were highly correlated by Chi-square analysis [PD and DH (p<2.2e-6); PD and INF (p=6.2e-10); INF and DH (p=0.0036)]. Gene-based testing identified the INS (insulin) gene as significantly associated with cluster 3 of SPTB. Conclusion We identified 5 major clusters of SPTB based on a phenotype tool and hierarchal clustering. There was significant correlation between several of the phenotypes. The INS gene was associated with familial factors underlying SPTB. PMID:26070700

Profiling physical activity motivation based on self-determination theory: a cluster analysis approach.

PubMed

Friederichs, Stijn Ah; Bolman, Catherine; Oenema, Anke; Lechner, Lilian

2015-01-01

In order to promote physical activity uptake and maintenance in individuals who do not comply with physical activity guidelines, it is important to increase our understanding of physical activity motivation among this group. The present study aimed to examine motivational profiles in a large sample of adults who do not comply with physical activity guidelines. The sample for this study consisted of 2473 individuals (31.4% male; age 44.6 ± 12.9). In order to generate motivational profiles based on motivational regulation, a cluster analysis was conducted. One-way analyses of variance were then used to compare the clusters in terms of demographics, physical activity level, motivation to be active and subjective experience while being active. Three motivational clusters were derived based on motivational regulation scores: a low motivation cluster, a controlled motivation cluster and an autonomous motivation cluster. These clusters differed significantly from each other with respect to physical activity behavior, motivation to be active and subjective experience while being active. Overall, the autonomous motivation cluster displayed more favorable characteristics compared to the other two clusters. The results of this study provide additional support for the importance of autonomous motivation in the context of physical activity behavior. The three derived clusters may be relevant in the context of physical activity interventions as individuals within the different clusters might benefit most from different intervention approaches. In addition, this study shows that cluster analysis is a useful method for differentiating between motivational profiles in large groups of individuals who do not comply with physical activity guidelines.

Quantum Materials at the Nanoscale - Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, Stephen Lance

The central aim of the Quantum Materials at the Nanoscale (QMN) cluster was to understand and control collective behavior involving the interplay of spins, orbitals, and charges, which governs many scientifically interesting and technologically important phenomena in numerous complex materials. Because these phenomena involve various competing interactions, and influence properties on many different length and energy scales in complex materials, tackling this important area of study motivated a collaborative effort that combined the diverse capabilities of QMN cluster experimentalists, the essential theoretical analysis provided by QMN cluster theorists, and the outstanding facilities and staff of the FSMRL. During the fundingmore » period 2007-2014, the DOE cluster grant for the Quantum Materials at the Nanoscale (QMN) cluster supported, at various times, 15 different faculty members (14 in Physics and 1 in Materials Science and Engineering), 7 postdoctoral research associates, and 57 physics and materials science PhD students. 41 of these PhD students have since graduated and have gone on to a variety of advanced technical positions at universities, industries, and national labs: 25 obtained postdoctoral positions at universities (14), industrial labs (2 at IBM), DOE national facilities (3 at Argonne National Laboratory, 1 at Brookhaven National Lab, 1 at Lawrence Berkeley National Lab, and 1 at Sandia National Lab), and other federal facilities (2 at NIST); 13 took various industrial positions, including positions at Intel (5), Quantum Design (1), Lasque Industries (1), Amazon (1), Bloomberg (1), and J.P. Morgan (1). Thus, the QMN grant provided the essential support for training a large number of technically advanced personnel who have now entered key national facilities, industries, and institutions. Additionally, during the period 2007-2015, the QMN cluster produced 159 publications (see pages 14-23), including 23 papers published in Physical Review Letters; 16 papers in Nature, Nature Physics, Nature Materials, or Nature Communications; 4 papers in Science, and 8 papers in Applied Physics Letters. In this report, we provide some key highlights of the collaborative projects in which the QMN cluster members have been involved since 2007.« less

Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters

NASA Astrophysics Data System (ADS)

2008-10-01

(Washington, DC. 08)- A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects. The discovery implies that existing radio telescopes have missed a large population of these colliding objects. It also provides an important confirmation of the theoretical prediction that colliding galaxy clusters accelerate electrons and other particles to very high energies through the process of turbulent waves. The team revealed their findings in the October 16, 2008 edition of Nature. This new population of objects is most easily detected at long wavelengths. Professor Greg Taylor of the University of New Mexico and scientific director of the Long Wavelength Array (LWA) points out, "This result is just the tip of the iceberg. When an emerging suite of much more powerful low frequency telescopes, including the LWA in New Mexico, turn their views to the cosmos, the sky will 'light up' with hundreds or even thousands of colliding galaxy clusters." NRL has played a key role in promoting the development of this generation of new instruments and is currently involved with the development of the LWA. NRL radio astronomer and LWA Project Scientist Namir Kassim says "Our discovery of a previously hidden class of low frequency cluster-radio sources is particularly important since the study of galaxy clusters was a primary motivation for development of the LWA." The discovery of the emission in the galaxy cluster Abell 521 (or A521 for short) was made using the Giant Metrewave Radiotelescope (GMRT) in India, and its long wavelength nature was confirmed by the National Science Foundation's (NRAO) Very Large Array (VLA) radio telescope in New Mexico. The attached image shows the radio emission at a wavelength of 125cm in red superimposed on a blue image made from data taken by the Chandra X-ray Observatory. X-ray Chandra X-ray Image The X-ray emission comes from hot thermal gas, a well-known sign-post of massive galaxy clusters. Furthermore, its elongated shape indicates that the cluster has undergone a recent violent collision or "merger event" in which another group or cluster of galaxies was swallowed up by the gravitational potential of the main cluster. Interferometrics Inc. and NRL scientist Tracy Clarke, who is also the LWA System Scientist, notes "In addition to teaching us about the nature of Dark Matter, merging clusters are also important in studies of the mysterious nature of Dark Energy. Understanding these two strange components of the Universe will help us understand its ultimate destiny." In the radio image there is a strong, oblong source of emission located on the lower left periphery of the X-ray gas detected by Chandra; this is a separate source. In the center of the cluster, within the region indicated by a dashed circle, there is radio emission which changes significantly with wavelength. At the longest wavelength (125 cm, shown) it is clearly detected, but at a wavelength of 49 cm it is much fainter, and it is almost entirely gone at 21 cm wavelength. This multi-wavelength picture of the diffuse emission is in good agreement with theoretical predictions for particle acceleration by turbulent waves generated by a violent collision. People Who Read This Also Read... Black Holes Have Simple Feeding Habits NASA’s Swift Satellite Catches First Supernova in The Act of Exploding Oldest Known Objects Are Surprisingly Immature Chandra Data Reveal Rapidly Whirling Black Holes In a broader astrophysical context, galaxy clusters are the largest gravitationally bound systems in the Universe and their collisions are the most energetic events since the Big Bang. Says team leader Gianfranco Brunetti (Instituto di Radioastronomia, Bologna, Italy), "The A521 system provides evidence that turbulence acts as a source of particle acceleration in an environment that is unique in the Universe due to its large spatial and temporal scales, and due to the low density and high temperature of the gas." The team included scientists from Instituto di Radioastronomia, the University of Bologna, the Smithsonian Astrophysical Observatory, the National Radio Astronomy Observatory, and the Naval Research Laboratory. Basic research in radio astronomy at the Naval Research Laboratory is supported by 6.1 base funding. The NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. The LWA, funding for which is provided by the Office of Naval Research, is led by the University of New Mexico, and includes NRL, The Applied Research Laboratory at the University of Texas at Austin, Virginia Tech, the Los Alamos National Laboratory, and the University of Iowa, with contributions and cooperation from NRAO. The Long Wavelength Array (LWA) website is http://lwa.unm.edu The Naval Research Laboratory is the Department of the Navy's corporate laboratory. NRL conducts a broad program of scientific research, technology, and advanced development. The Laboratory, with a total complement of nearly 2,500 personnel, is located in southwest Washington, DC, with other major sites at the Stennis Space Center, MS; and Monterey, CA.

Testing cold dark matter models using Hubble flow variations

NASA Astrophysics Data System (ADS)

Shi, Xiangdong

1999-05-01

COBE-normalized flat (matter plus cosmological constant) and open cold dark matter (CDM) models are tested by comparing their expected Hubble flow variations and the observed variations in a Type Ia supernova sample and a Tully-Fisher cluster sample. The test provides a probe of the CDM power spectrum on scales of 0.02h Mpc^-1<~ k<~ 0.2h Mpc^-1, free of the bias factor b. The results favour a low matter content universe, or a flat matter-dominated universe with a very low Hubble constant and/or a very small spectral index n^ps, with the best fits having Ο_0~ 0.3 to 0.4. The test is found to be more discriminative to the open CDM models than to the flat CDM models. For example, the test results are found to be compatible with those from the X-ray cluster abundance measurements at smaller length-scales, and consistent with the galaxy and cluster correlation analysis of Peacock & Dodds at similar length-scales, if our universe is flat; but the results are marginally incompatible with the X-ray cluster abundance measurements if our universe is open. The open CDM results are consistent with that of Peacock & Dodds only if the matter density of the universe is less than about 60 per cent of the critical density. The shortcoming of the test is discussed, so are ways to minimize it.

Ruprecht 3: An old star cluster remnant?

NASA Astrophysics Data System (ADS)

Pavani, D. B.; Bica, E.; Ahumada, A. V.; Clariá, J. J.

2003-02-01

2MASS J and H photometry and integrated spectroscopy are employed to study the nature of the poorly populated compact concentration of stars Ruprecht 3, which was previously catalogued as an open cluster. The integrated spectrum remarkably resembles that of a moderately metal-rich globular cluster. The distribution of the object stars in the colour-magnitude diagram is compatible with that of a 1.5 +/- 0.5 Gyr open cluster or older, depending on whether the bluer stars are interpreted as turnoff stars or blue stragglers, respectively. We derive for the object a distance from the Sun dsun = 0.72 +0.04-0.03 kpc and a colour excess E(B-V) = 0.04. Although a globular cluster remnant cannot be ruled out, the integrated spectrum resemblance to that of a globular cluster probably reflects a stochastic effect owing to the few brighter stars. The structural and photometric properties of Ruprecht 3 are compatible with what would be expected for an intermediate-age open cluster remnant. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan, Argentina.

Chill, Be Cool Man: African American Men, Identity, Coping, and Aggressive Ideation

PubMed Central

Thomas, Alvin; Hammond, Wizdom Powell; Kohn-Wood, Laura P.

2016-01-01

Aggression is an important correlate of violence, depression, coping, and suicide among emerging young African American males. Yet most researchers treat aggression deterministically, fail to address cultural factors, or consider the potential for individual characteristics to exert an intersectional influence on this psychosocial outcome. Addressing this gap, we consider the moderating effect of coping on the relationship between masculine and racial identity and aggressive ideation among African American males (N = 128) drawn from 2 large Midwestern universities. Using the phenomenological variant of ecological systems theory and person-centered methodology as a guide, hierarchical cluster analysis grouped participants into profile groups based on their responses to both a measure of racial identity and a measure of masculine identity. Results from the cluster analysis revealed 3 distinct identity clusters: Identity Ambivalent, Identity Appraising, and Identity Consolidated. Although these cluster groups did not differ with regard to coping, significant differences were observed between cluster groups in relation to aggressive ideation. Further, a full model with identity profile clusters, coping, and aggressive ideation indicates that cluster membership significantly moderates the relationship between coping and aggressive ideation. The implications of these data for intersecting identities of African American men, and the association of identity and outcomes related to risk for mental health and violence, are discussed. PMID:25090145

Chill, be cool man: African American men, identity, coping, and aggressive ideation.

PubMed

Thomas, Alvin; Hammond, Wizdom Powell; Kohn-Wood, Laura P

2015-07-01

Aggression is an important correlate of violence, depression, coping, and suicide among emerging young African American males. Yet most researchers treat aggression deterministically, fail to address cultural factors, or consider the potential for individual characteristics to exert an intersectional influence on this psychosocial outcome. Addressing this gap, we consider the moderating effect of coping on the relationship between masculine and racial identity and aggressive ideation among African American males (N = 128) drawn from 2 large Midwestern universities. Using the phenomenological variant of ecological systems theory and person-centered methodology as a guide, hierarchical cluster analysis grouped participants into profile groups based on their responses to both a measure of racial identity and a measure of masculine identity. Results from the cluster analysis revealed 3 distinct identity clusters: Identity Ambivalent, Identity Appraising, and Identity Consolidated. Although these cluster groups did not differ with regard to coping, significant differences were observed between cluster groups in relation to aggressive ideation. Further, a full model with identity profile clusters, coping, and aggressive ideation indicates that cluster membership significantly moderates the relationship between coping and aggressive ideation. The implications of these data for intersecting identities of African American men, and the association of identity and outcomes related to risk for mental health and violence, are discussed. (c) 2015 APA, all rights reserved).

Dynamic clustering scheme based on the coordination of management and control in multi-layer and multi-region intelligent optical network

NASA Astrophysics Data System (ADS)

Niu, Xiaoliang; Yuan, Fen; Huang, Shanguo; Guo, Bingli; Gu, Wanyi

2011-12-01

A Dynamic clustering scheme based on coordination of management and control is proposed to reduce network congestion rate and improve the blocking performance of hierarchical routing in Multi-layer and Multi-region intelligent optical network. Its implement relies on mobile agent (MA) technology, which has the advantages of efficiency, flexibility, functional and scalability. The paper's major contribution is to adjust dynamically domain when the performance of working network isn't in ideal status. And the incorporation of centralized NMS and distributed MA control technology migrate computing process to control plane node which releases the burden of NMS and improves process efficiently. Experiments are conducted on Multi-layer and multi-region Simulation Platform for Optical Network (MSPON) to assess the performance of the scheme.

Spectroscopy of Luminous Compact Blue Galaxies in Distant Clusters. I. Spectroscopic Data

NASA Astrophysics Data System (ADS)

Crawford, Steven M.; Wirth, Gregory D.; Bershady, Matthew A.; Hon, Kimo

2011-11-01

We used the DEIMOS spectrograph on the Keck II Telescope to obtain spectra of galaxies in the fields of five distant, rich galaxy clusters over the redshift range 0.5 < z < 0.9 in a search for luminous compact blue galaxies (LCBGs). Unlike traditional studies of galaxy clusters, we preferentially targeted blue cluster members identified via multi-band photometric pre-selection based on imaging data from the WIYN telescope. Of the 1288 sources that we targeted, we determined secure spectroscopic redshifts for 848 sources, yielding a total success rate of 66%. Our redshift measurements are in good agreement with those previously reported in the literature, except for 11 targets which we believe were previously in error. Within our sample, we confirm the presence of 53 LCBGs in the five galaxy clusters. The clusters all stand out as distinct peaks in the redshift distribution of LCBGs with the average number density of LCBGs ranging from 1.65 ± 0.25 Mpc-3 at z = 0.55 to 3.13 ± 0.65 Mpc-3 at z = 0.8. The number density of LCBGs in clusters exceeds the field density by a factor of 749 ± 116 at z = 0.55; at z = 0.8, the corresponding ratio is E = 416 ± 95. At z = 0.55, this enhancement is well above that seen for blue galaxies or the overall cluster population, indicating that LCBGs are preferentially triggered in high-density environments at intermediate redshifts. Based in part on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

COSMOS: Python library for massively parallel workflows.

PubMed

Gafni, Erik; Luquette, Lovelace J; Lancaster, Alex K; Hawkins, Jared B; Jung, Jae-Yoon; Souilmi, Yassine; Wall, Dennis P; Tonellato, Peter J

2014-10-15

Efficient workflows to shepherd clinically generated genomic data through the multiple stages of a next-generation sequencing pipeline are of critical importance in translational biomedical science. Here we present COSMOS, a Python library for workflow management that allows formal description of pipelines and partitioning of jobs. In addition, it includes a user interface for tracking the progress of jobs, abstraction of the queuing system and fine-grained control over the workflow. Workflows can be created on traditional computing clusters as well as cloud-based services. Source code is available for academic non-commercial research purposes. Links to code and documentation are provided at http://lpm.hms.harvard.edu and http://wall-lab.stanford.edu. dpwall@stanford.edu or peter_tonellato@hms.harvard.edu. Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press.

BioContainers: an open-source and community-driven framework for software standardization.

PubMed

da Veiga Leprevost, Felipe; Grüning, Björn A; Alves Aflitos, Saulo; Röst, Hannes L; Uszkoreit, Julian; Barsnes, Harald; Vaudel, Marc; Moreno, Pablo; Gatto, Laurent; Weber, Jonas; Bai, Mingze; Jimenez, Rafael C; Sachsenberg, Timo; Pfeuffer, Julianus; Vera Alvarez, Roberto; Griss, Johannes; Nesvizhskii, Alexey I; Perez-Riverol, Yasset

2017-08-15

BioContainers (biocontainers.pro) is an open-source and community-driven framework which provides platform independent executable environments for bioinformatics software. BioContainers allows labs of all sizes to easily install bioinformatics software, maintain multiple versions of the same software and combine tools into powerful analysis pipelines. BioContainers is based on popular open-source projects Docker and rkt frameworks, that allow software to be installed and executed under an isolated and controlled environment. Also, it provides infrastructure and basic guidelines to create, manage and distribute bioinformatics containers with a special focus on omics technologies. These containers can be integrated into more comprehensive bioinformatics pipelines and different architectures (local desktop, cloud environments or HPC clusters). The software is freely available at github.com/BioContainers/. yperez@ebi.ac.uk. © The Author(s) 2017. Published by Oxford University Press.

Orbits of Four Very Massive Binaries in the R136 Cluster

NASA Astrophysics Data System (ADS)

Massey, Philip; Penny, Laura R.; Vukovich, Julia

2002-02-01

We present radial velocity and photometry for four early-type, massive, double-lined spectroscopic binaries in the R136 cluster. Three of these systems are eclipsing, allowing orbital inclinations to be determined. One of these systems, R136-38 (O3 V+O6 V), has one of the highest masses ever measured for the primary, 57 Msolar. Comparison of our masses with those derived from standard evolutionary tracks shows excellent agreement. We also identify five other light variables in the R136 cluster that are worthy of follow-up study. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposal 8217.

Galaxy Clusters

NASA Astrophysics Data System (ADS)

Miller, Christopher J. Miller

2012-03-01

There are many examples of clustering in astronomy. Stars in our own galaxy are often seen as being gravitationally bound into tight globular or open clusters. The Solar System's Trojan asteroids cluster at the gravitational Langrangian in front of Jupiter’s orbit. On the largest of scales, we find gravitationally bound clusters of galaxies, the Virgo cluster (in the constellation of Virgo at a distance of ˜50 million light years) being a prime nearby example. The Virgo cluster subtends an angle of nearly 8◦ on the sky and is known to contain over a thousand member galaxies. Galaxy clusters play an important role in our understanding of theUniverse. Clusters exist at peaks in the three-dimensional large-scale matter density field. Their sky (2D) locations are easy to detect in astronomical imaging data and their mean galaxy redshifts (redshift is related to the third spatial dimension: distance) are often better (spectroscopically) and cheaper (photometrically) when compared with the entire galaxy population in large sky surveys. Photometric redshift (z) [Photometric techniques use the broad band filter magnitudes of a galaxy to estimate the redshift. Spectroscopic techniques use the galaxy spectra and emission/absorption line features to measure the redshift] determinations of galaxies within clusters are accurate to better than delta_z = 0.05 [7] and when studied as a cluster population, the central galaxies form a line in color-magnitude space (called the the E/S0 ridgeline and visible in Figure 16.3) that contains galaxies with similar stellar populations [15]. The shape of this E/S0 ridgeline enables astronomers to measure the cluster redshift to within delta_z = 0.01 [23]. The most accurate cluster redshift determinations come from spectroscopy of the member galaxies, where only a fraction of the members need to be spectroscopically observed [25,42] to get an accurate redshift to the whole system. If light traces mass in the Universe, then the locations of galaxy clusters will be at locations of the peaks in the true underlying (mostly) dark matter density field. Kaiser (1984) [19] called this the high-peak model, which we demonstrate in Figure 16.1. We show a two-dimensional representation of a density field created by summing plane-waves with a predetermined power and with random wave-vector directions. In the left panel, we plot only the largest modes, where we see the density peaks (black) and valleys (white) in the combined field. In the right panel, we allow for smaller modes. You can see that the highest density peaks in the left panel contain smaller-scale, but still high-density peaks. These are the locations of future galaxy clusters. The bottom panel shows just these cluster-scale peaks. As you can see, the peaks themselves are clustered, and instead of just one large high-density peak in the original density field (see the left panel), the smaller modes show that six peaks are "born" within the broader, underlying large-scale density modes. This exemplifies the "bias" or amplified structure that is traced by galaxy clusters [19]. Clusters are rare, easy to find, and their member galaxies provide good distance estimates. In combination with their amplified clustering signal described above, galaxy clusters are considered an efficient and precise tracer of the large-scale matter density field in the Universe. Galaxy clusters can also be used to measure the baryon content of the Universe [43]. They can be used to identify gravitational lenses [38] and map the distribution of matter in clusters. The number and spatial distribution of galaxy clusters can be used to constrain cosmological parameters, like the fraction of the energy density in the Universe due to matter (Omega_matter) or the variation in the density field on fixed physical scales (sigma_8) [26,33]. The individual clusters act as “Island Universes” and as such are laboratories here we can study the evolution of the properties of the cluster, like the hot, gaseous intra-cluster medium or shapes, colors, and star-formation histories of the member galaxies [17].

An Approach to Cluster EU Member States into Groups According to Pathways of Salmonella in the Farm-to-Consumption Chain for Pork Products.

PubMed

Vigre, Håkan; Domingues, Ana Rita Coutinho Calado; Pedersen, Ulrik Bo; Hald, Tine

2016-03-01

The aim of the project as the cluster analysis was to in part to develop a generic structured quantitative microbiological risk assessment (QMRA) model of human salmonellosis due to pork consumption in EU member states (MSs), and the objective of the cluster analysis was to group the EU MSs according to the relative contribution of different pathways of Salmonella in the farm-to-consumption chain of pork products. In the development of the model, by selecting a case study MS from each cluster the model was developed to represent different aspects of pig production, pork production, and consumption of pork products across EU states. The objective of the cluster analysis was to aggregate MSs into groups of countries with similar importance of different pathways of Salmonella in the farm-to-consumption chain using available, and where possible, universal register data related to the pork production and consumption in each country. Based on MS-specific information about distribution of (i) small and large farms, (ii) small and large slaughterhouses, (iii) amount of pork meat consumed, and (iv) amount of sausages consumed we used nonhierarchical and hierarchical cluster analysis to group the MSs. The cluster solutions were validated internally using statistic measures and externally by comparing the clustered MSs with an estimated human incidence of salmonellosis due to pork products in the MSs. Finally, each cluster was characterized qualitatively using the centroids of the clusters. © 2016 Society for Risk Analysis.

Gamma-Ray Emission from Galaxy Clusters : DARK MATTER AND COSMIC-RAYS

NASA Astrophysics Data System (ADS)

Pinzke, Anders

The quest for the first detection of a galaxy cluster in the high energy gamma-ray regime is ongoing, and even though clusters are observed in several other wave-bands, there is still no firm detection in gamma-rays. To complement the observational efforts we estimate the gamma-ray contributions from both annihilating dark matter and cosmic-ray (CR) proton as well as CR electron induced emission. Using high-resolution simulations of galaxy clusters, we find a universal concave shaped CR proton spectrum independent of the simulated galaxy cluster. Specifically, the gamma-ray spectra from decaying neutral pions, which are produced by CR protons, dominate the cluster emission. Furthermore, based on our derived flux and luminosity functions, we identify the galaxy clusters with the brightest galaxy clusters in gamma-rays. While this emission is challenging to detect using the Fermi satellite, major observations with Cherenkov telescopes in the near future may put important constraints on the CR physics in clusters. To extend these predictions, we use a dark matter model that fits the recent electron and positron data from Fermi, PAMELA, and H.E.S.S. with remarkable precision, and make predictions about the expected gamma-ray flux from nearby clusters. In order to remain consistent with the EGRET upper limit on the gamma-ray emission from Virgo, we constrain the minimum mass of substructures for cold dark matter halos. In addition, we find comparable levels of gamma-ray emission from CR interactions and dark matter annihilations without Sommerfeld enhancement.

Local-world and cluster-growing weighted networks with controllable clustering

NASA Astrophysics Data System (ADS)

Yang, Chun-Xia; Tang, Min-Xuan; Tang, Hai-Qiang; Deng, Qiang-Qiang

2014-12-01

We constructed an improved weighted network model by introducing local-world selection mechanism and triangle coupling mechanism based on the traditional BBV model. The model gives power-law distributions of degree, strength and edge weight and presents the linear relationship both between the degree and strength and between the degree and the clustering coefficient. Particularly, the model is equipped with an ability to accelerate the speed increase of strength exceeding that of degree. Besides, the model is more sound and efficient in tuning clustering coefficient than the original BBV model. Finally, based on our improved model, we analyze the virus spread process and find that reducing the size of local-world has a great inhibited effect on virus spread.

Improving data retrieval quality: Evidence based medicine perspective.

PubMed

Kamalov, M; Dobrynin, V; Balykina, J; Kolbin, A; Verbitskaya, E; Kasimova, M

2015-01-01

The actively developing approach in modern medicine is the approach focused on principles of evidence-based medicine. The assessment of quality and reliability of studies is needed. However, in some cases studies corresponding to the first level of evidence may contain errors in randomized control trials (RCTs). Solution of the problem is the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Studies both in the fields of medicine and information retrieval are conducted for developing search engines for the MEDLINE database [1]; combined techniques for summarization and information retrieval targeted to solving problems of finding the best medication based on the levels of evidence are being developed [2]. Based on the relevance and demand for studies both in the field of medicine and information retrieval, it was decided to start the development of a search engine for the MEDLINE database search on the basis of the Saint-Petersburg State University with the support of Pavlov First Saint-Petersburg State Medical University and Tashkent Institute of Postgraduate Medical Education. Novelty and value of the proposed system are characterized by the use of ranking method of relevant abstracts. It is suggested that the system will be able to perform ranking based on studies level of evidence and to apply GRADE criteria for system evaluation. The assigned task falls within the domain of information retrieval and machine learning. Based on the results of implementation from previous work [3], in which the main goal was to cluster abstracts from MEDLINE database by subtypes of medical interventions, a set of algorithms for clustering in this study was selected: K-means, K-means ++, EM from the sklearn (http://scikit-learn.org) and WEKA (http://www.cs.waikato.ac.nz/~ml/weka/) libraries, together with the methods of Latent Semantic Analysis (LSA) [4] choosing the first 210 facts and the model "bag of words" [5] to represent clustered documents. During the process of abstracts classification, few algorithms were tested including: Complement Naive Bayes [6], Sequential Minimal Optimization (SMO) [7] and non linear SVM from the WEKA library. The first step of this study was to markup abstracts of articles from the MEDLINE by containing and not containing a medical intervention. For this purpose, based on our previous work [8] a web-crawler was modified to perform the necessary markuping. The next step was to evaluate the clustering algorithms at the markup abstracts. As a result of clustering abstracts by two groups, when applying the LSA and choosing first 210 facts, the following results were obtained:1) K-means: Purity = 0,5598, Normalized Entropy = 0.5994;2)K-means ++: Purity = 0,6743, Normalized Entropy = 0.4996;3)EM: Purity = 0,5443, Normalized Entropy = 0.6344.When applying the model "bag of words":1)K-means: Purity = 0,5134, Normalized Entropy = 0.6254;2)K-means ++: Purity = 0,5645, Normalized Entropy = 0.5299;3)EM: Purity = 0,5247, Normalized Entropy = 0.6345.Then, studies which contain medical intervention have been considered and classified by the subtypes of medical interventions. At the process of classification abstracts by subtypes of medical interventions, abstracts were presented as a "bag of words" model with the removal of stop words. 1)Complement Naive Bayes: macro F-measure = 0.6934, micro F-measure = 0.7234;2)Sequantial Minimal Optimization: macro F-measure = 0.6543, micro F-measure = 0.7042;3)Non linear SVM: macro F-measure = 0.6835, micro F-measure = 0.7642. Based on the results of computational experiments, the best results of abstract clustering by containing and not containing medical intervention were obtained using the K-Means ++ algorithm together with LSA, choosing the first 210 facts. The quality of classification abstracts by subtypes of medical interventions value for existing ones [8] has been improved using non linear SVM algorithm, with "bag of words" model and the removal of stop words. The results of clustering obtained in this study will help in grouping abstracts by levels of evidence, using the classification by subtypes of medical interventions and it will be possible to extract information from the abstracts on specific types of interventions.

Modeling the Dark Matter of Galaxy Clusters Using the Tensor-Vector-Scalar Theory of Alternate Gravity

NASA Astrophysics Data System (ADS)

Ragozzine, Brett

The invocation of dark matter in the universe is predicated upon gravitational observations that cannot be explained by the amount of luminous matter that we detect. There is an ongoing debate over which gravitational model is correct. The work herein tests a prescription of gravity theory known as Tensor-Vector-Scalar and is based upon the work of Angus et al. (2007). We add upon this work by extending the sample of galaxy clusters to five and testing the accepted Navarro, Frenk & White (NFW) dark matter potential (Navarro et al., 1996). Our independent implementation of this method includes weak gravitational lensing analysis to determine the amount of dark matter in these galaxy clusters by calculating the gas fraction ƒgas = Mgas=Mtot. The ability of the Tensor-Vector-Scalar theory to predict a consistent ƒgas across all galaxy clusters is a measure of its liklihood of being the correct gravity model.

Recent heavy particle decay in a matter dominated universe

NASA Astrophysics Data System (ADS)

Olive, K. A.; Seckel, D.; Vishniac, E.

1984-09-01

The cold matter scenario for galaxy formation solves the dark matter problem very nicely on small scales corresponding to galaxies and clusters of galaxies. It is, however, difficult to reconcile with a Universe with an Einstein-deSitter value of (UC OMEGA) = 1. Cold matter and (UC OMEGA) = 1 can be made compatible while retaining the feature that the Universe is matter dominated today. This is done by means of heavy (cold) particles whose decay subsequently leads to the unbinding of a large fraction of lighter clustered matter.

Recent heavy-particle decay in a matter-dominated universe

NASA Astrophysics Data System (ADS)

Olive, K. A.; Seckel, D.; Vishniac, E.

1985-05-01

The cold-matter scenario for galaxy formation solves the dark-matter problem very nicely on small scales corresponding to galaxies and clusters of galaxies. It is, however, difficult to reconcile with a universe with an Einstein-deSitter value of Ω = 1. It is shown here that cold matter and Ω = 1 can be made compatible while retaining the feature that the universe is matter-dominated today. This is done by means of heavy (cold) particles whose decay subsequently leads to the unbinding of a large fraction of lighter clustered matter.

Large-scale motions in the universe: Using clusters of galaxies as tracers

NASA Technical Reports Server (NTRS)

Gramann, Mirt; Bahcall, Neta A.; Cen, Renyue; Gott, J. Richard

1995-01-01

Can clusters of galaxies be used to trace the large-scale peculiar velocity field of the universe? We answer this question by using large-scale cosmological simulations to compare the motions of rich clusters of galaxies with the motion of the underlying matter distribution. Three models are investigated: Omega = 1 and Omega = 0.3 cold dark matter (CDM), and Omega = 0.3 primeval baryonic isocurvature (PBI) models, all normalized to the Cosmic Background Explorer (COBE) background fluctuations. We compare the cluster and mass distribution of peculiar velocities, bulk motions, velocity dispersions, and Mach numbers as a function of scale for R greater than or = 50/h Mpc. We also present the large-scale velocity and potential maps of clusters and of the matter. We find that clusters of galaxies trace well the large-scale velocity field and can serve as an efficient tool to constrain cosmological models. The recently reported bulk motion of clusters 689 +/- 178 km/s on approximately 150/h Mpc scale (Lauer & Postman 1994) is larger than expected in any of the models studied (less than or = 190 +/- 78 km/s).

Cluster-guided imaging-based CFD analysis of airflow and particle deposition in asthmatic human lungs

NASA Astrophysics Data System (ADS)

Choi, Jiwoong; Leblanc, Lawrence; Choi, Sanghun; Haghighi, Babak; Hoffman, Eric; Lin, Ching-Long

2017-11-01

The goal of this study is to assess inter-subject variability in delivery of orally inhaled drug products to small airways in asthmatic lungs. A recent multiscale imaging-based cluster analysis (MICA) of computed tomography (CT) lung images in an asthmatic cohort identified four clusters with statistically distinct structural and functional phenotypes associating with unique clinical biomarkers. Thus, we aimed to address inter-subject variability via inter-cluster variability. We selected a representative subject from each of the 4 asthma clusters as well as 1 male and 1 female healthy controls, and performed computational fluid and particle simulations on CT-based airway models of these subjects. The results from one severe and one non-severe asthmatic cluster subjects characterized by segmental airway constriction had increased particle deposition efficiency, as compared with the other two cluster subjects (one non-severe and one severe asthmatics) without airway constriction. Constriction-induced jets impinging on distal bifurcations led to excessive particle deposition. The results emphasize the impact of airway constriction on regional particle deposition rather than disease severity, demonstrating the potential of using cluster membership to tailor drug delivery. NIH Grants U01HL114494 and S10-RR022421, and FDA Grant U01FD005837. XSEDE.

Ophiuchus: An optical view of a very massive cluster of galaxies hidden behind the Milky Way ⋆

NASA Astrophysics Data System (ADS)

Durret, F.; Wakamatsu, K.; Nagayama, T.; Adami, C.; Biviano, A.

2015-11-01

Context. The Ophiuchus cluster, at a redshift z = 0.0296, is known from X-rays to be one of the most massive nearby clusters, but its optical properties have not been investigated in detail because of its very low Galactic latitude. Aims: We discuss the optical properties of the galaxies in the Ophiuchus cluster, in particular, with the aim of understanding its dynamical properties better. Methods: We have obtained deep optical imaging in several bands with various telescopes, and applied a sophisticated method to model and subtract the contributions of stars to measure galaxy magnitudes as accurately as possible. The colour-magnitude relations obtained show that there are hardly any blue galaxies in Ophiuchus (at least brighter than r' ≤ 19.5), and this is confirmed by the fact that we only detect two galaxies in Hα. We also obtained a number of spectra with ESO-FORS2, which we combined with previously available redshifts. Altogether, we have 152 galaxies with spectroscopic redshifts in the 0.02 ≤ z ≤ 0.04 range, and 89 galaxies with both a redshift within the cluster redshift range and a measured r' band magnitude (limited to the Megacam 1 × 1 deg2 field). Results: A complete dynamical analysis based on the galaxy redshifts available shows that the overall cluster is relaxed and has a mass of 1.1 × 1015 M⊙. The Sernal-Gerbal method detects a main structure and a much smaller substructure, which are not separated in projection. Conclusions: From its dynamical properties derived from optical data, the Ophiuchus cluster seems overall to be a relaxed structure, or at most a minor merger, though in X-rays the central region (radius ~ 150 kpc) may show evidence for merging effects. Based on observations obtained with MegaPrime/MegaCam (program 10AF02), a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Based on observations performed with ESO Telescopes at the La Silla Paranal Observatory under programme ID 085.A-0016(C). Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope (programme 2009B-0340 on SOI/SOAR), which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration, and of the SIMBAD database, operated at CDS, Strasbourg, France.Tables A.1-A.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/583/A124

ATP hydrolysis in Eg5 kinesin involves a catalytic two-water mechanism.

PubMed

Parke, Courtney L; Wojcik, Edward J; Kim, Sunyoung; Worthylake, David K

2010-02-19

Motor proteins couple steps in ATP binding and hydrolysis to conformational switching both in and remote from the active site. In our kinesin.AMPPPNP crystal structure, closure of the active site results in structural transformations appropriate for microtubule binding and organizes an orthosteric two-water cluster. We conclude that a proton is shared between the lytic water, positioned for gamma-phosphate attack, and a second water that serves as a general base. To our knowledge, this is the first experimental detection of the catalytic base for any ATPase. Deprotonation of the second water by switch residues likely triggers subsequent large scale structural rearrangements. Therefore, the catalytic base is responsible for initiating nucleophilic attack of ATP and for relaying the positive charge over long distances to initiate mechanotransduction. Coordination of switch movements via sequential proton transfer along paired water clusters may be universal for nucleotide triphosphatases with conserved active sites, such as myosins and G-proteins.

Ten Billion Years of Brightest Cluster Galaxy Alignments

NASA Astrophysics Data System (ADS)

West, Michael J.

2017-07-01

Astronomers long assumed that galaxies are randomly oriented in space. However, it's now clear that some have preferred orientations with respect to their surroundings. Chief among these are the giant ellipticals found at the centers of rich galaxy clusters, whose major axes are often aligned with those of their host clusters - a remarkable coherence of structures over millions of light years. A better understanding of these alignments can yield new insights into the processes that have shaped galaxies over the history of the universe. Using Hubble Space Telescope observations of high-redshift galaxy clusters, we show for the first time that such alignments are seen at epochs when the universe was only one-third its current age. These results suggest that the brightest galaxies in clusters are the product of a special formation history, one influenced by development of the cosmic web over billions of years.

QoE collaborative evaluation method based on fuzzy clustering heuristic algorithm.

PubMed

Bao, Ying; Lei, Weimin; Zhang, Wei; Zhan, Yuzhuo

2016-01-01

At present, to realize or improve the quality of experience (QoE) is a major goal for network media transmission service, and QoE evaluation is the basis for adjusting the transmission control mechanism. Therefore, a kind of QoE collaborative evaluation method based on fuzzy clustering heuristic algorithm is proposed in this paper, which is concentrated on service score calculation at the server side. The server side collects network transmission quality of service (QoS) parameter, node location data, and user expectation value from client feedback information. Then it manages the historical data in database through the "big data" process mode, and predicts user score according to heuristic rules. On this basis, it completes fuzzy clustering analysis, and generates service QoE score and management message, which will be finally fed back to clients. Besides, this paper mainly discussed service evaluation generative rules, heuristic evaluation rules and fuzzy clustering analysis methods, and presents service-based QoE evaluation processes. The simulation experiments have verified the effectiveness of QoE collaborative evaluation method based on fuzzy clustering heuristic rules.

Effectiveness of a lifestyle intervention led by female community health volunteers versus usual care in blood pressure reduction (COBIN): an open-label, cluster-randomised trial.

PubMed

Neupane, Dinesh; McLachlan, Craig S; Mishra, Shiva Raj; Olsen, Michael Hecht; Perry, Henry B; Karki, Arjun; Kallestrup, Per

2018-01-01

Elevated blood pressure greatly contributes to cardiovascular deaths in low-income and middle-income countries. We aimed to investigate the effectiveness of a population-level intervention led by existing community health workers in reducing the burden of hypertension in a low-income population. We did a community-based, open-label, two-group, cluster-randomised controlled trial in Nepal. Using computer-generated codes, we randomly assigned (1:1) 14 clusters to a lifestyle intervention led by female community health volunteers (FCHVs) or usual care (control group). In the intervention group, 43 FCHVs provided home visits every 4 months for lifestyle counselling and blood pressure monitoring. Eligible participants had been involved in a previous population-based survey, were aged 25-65 years, did not have plans to migrate outside the study area, and were not severely ill or pregnant. The primary outcome was mean systolic blood pressure at 1 year. We included all participants who remained in the trial at 1 year in the primary analysis. This trial is registered with ClinicalTrials.gov, number NCT02428075. Between April 1, 2015, and Dec 31, 2015, we recruited 1638 participants (939 assigned to intervention; 699 assigned to control). At 1 year, 855 participants remained in the intervention group (425 were normotensive, 175 were prehypertensive, and 255 had hypertension) and 613 remained in the control group (305 were normotensive, 128 were prehypertensive, and 180 had hypertension). The mean systolic blood pressure at 1 year was significantly lower in the intervention group than in the control group for all cohorts: the difference was -2·28 mm Hg (95% CI -3·77 to -0·79, p=0·003) for participants who were normotensive, -3·08 mm Hg (-5·58 to -0·59, p=0·015) for participants who were prehypertensive, and -4·90 mm Hg (-7·78 to -2·00, p=0·001) for participants who were hypertensive. A simple, FCHV-led lifestyle intervention coupled with monitoring of blood pressure is effective for reduction of blood pressure in individuals with hypertension and ameliorates age-related increases in blood pressure in adults without hypertension in the general population of Nepal. Aarhus University, Jayanti Memorial Trust. Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.

Naratriptan in the Prophylactic Treatment of Cluster Headache.

PubMed

Ito, Yasuo; Mitsufuji, Takashi; Asano, Yoshio; Shimazu, Tomokazu; Kato, Yuji; Tanahashi, Norio; Maruki, Yuichi; Sakai, Fumihiko; Yamamoto, Toshimasa; Araki, Nobuo

2017-10-01

Objective Naratriptan has been reported to reduce the frequency of cluster headache. The purpose of this study was to determine whether naratriptan is effective as a prophylactic treatment for cluster headache in Japan. Methods We retrospectively reviewed all 43 patients with cluster headache who received preventive treatment with naratriptan from April 2009 to April 2015. The International Classification of Headache Disorders, 3rd Edition (beta version) (ICHD-3 beta) was used to diagnose cluster headache. This study was conducted at 3 centers (Department of Neurology, Saitama Medical University; Saitama Neuropsychiatric Institute; Saitama Medical University International Medical Center). Patients were recruited from these specialized headache outpatient centers. Naratriptan was taken before the patient went to bed. Results The study population included 30 men (69.8%) and 13 women (30.2%). Twenty-two cases received other preventive treatments (51.2%), while 21 cases only received naratriptan (48.8%). Among the 43 cases, 37 patients (86.0%) achieved an improvement of cluster headache on naratriptan. Conclusion Naratriptan has been suggested as a preventive medicine for cluster headache because of the longer the biological half-life in comparison to other triptans. The internal use of naratriptan 2 hours before attacks appears to achieve a good response in patients with cluster headache.

Chandra X-Ray Observatory Image of the Distant Galaxy, 3C294

NASA Technical Reports Server (NTRS)

2000-01-01

This most distant x-ray cluster of galaxies yet has been found by astronomers using Chandra X-ray Observatory (CXO). Approximately 10 billion light-years from Earth, the cluster 3C294 is 40 percent farther than the next most distant x-ray galaxy cluster. The existence of such a faraway cluster is important for understanding how the universe evolved. CXO's image reveals an hourglass-shaped region of x-ray emissions centered on the previously known central radio source (seen in this image as the blue central object) that extends outward for 60,000 light- years. The vast clouds of hot gas that surround such galaxies in clusters are thought to be heated by collapse toward the center of the cluster. Until CXO, x-ray telescopes have not had the needed sensitivity to identify such distant clusters of galaxies. Galaxy clusters are the largest gravitationally bound structures in the universe. The intensity of the x-rays in this CXO image of 3C294 is shown as red for low energy x-rays, green for intermediate, and blue for the most energetic x-rays. (Photo credit: NASA/loA/A. Fabian et al)

Gas Dynamics in Galaxy Clusters

NASA Astrophysics Data System (ADS)

McCourt, Michael Kingsley, Jr.

Galaxy clusters are the most massive structures in the universe and, in the hierarchical pattern of cosmological structure formation, the largest objects in the universe form last. Galaxy clusters are thus interesting objects for a number of reasons. Three examples relevant to this thesis are: 1. Constraining the properties of dark energy: Due to the hierarchical nature of structure formation, the largest objects in the universe form last. The cluster mass function is thus sensitive to the entire expansion history of the universe and can be used to constrain the properties of dark energy. This constraint complements others derived from the CMB or from Type Ia supernovae and provides an important, independent confirmation of such methods. In particular, clusters provide detailed information about the equation of state parameter w because they sample a large redshift range z ˜ 0 - 1. 2. Probing galaxy formation: Clusters contain the most massive galaxies in the uni- verse, and the most massive black holes; because clusters form so late, we can still witness the assembly of these objects in the nearby universe. Clusters thus provide a more detailed view of galaxy formation than is possible in studies of lower-mass ob- jects. An important example comes from x-ray studies of clusters, which unexpectedly found that star formation in massive galaxies in clusters is closely correlated with the properties of the hot, virialized gas in their halos. This correlation persists despite the enormous separation in temperature, in dynamical time-scales, and in length-scales between the virialized gas in the halo and the star-forming regions in the galaxy. This remains a challenge to interpret theoretically. 3. Developing our knowledge of dilute plasmas: The masses and sizes of galaxy clusters imply that the plasma which permeates them is both very hot (˜ 108 K) and very dilute (˜ 10 -2 cm-3). This plasma is collisional enough to be considered a fluid, but collisionless enough to develop significant anisotropies with respect to the local magnetic field. This interesting regime is one of the frontiers in theoretical studies of fluid dynamics. Unlike other astrophysical environments of similar collisionality (e. g. accretion disk coronae), galaxy clusters are optically thin and subtend large angles on the sky. Thus, they are easily observed in the x-ray (to constrain thermal processes) and in the radio (to constrain non-thermal processes) and provide a wonderful environment to develop our understanding of dilute plasmas. This thesis studies the dynamics of the hot gas in galaxy clusters, which touches on all three of the above topics. Chapter 2 shows that galaxy clusters are likely to be unstable to a new, vigorous form of convection. As a dynamical process which involves thermodynamic and magnetic properties of the gas, this convection bears directly on our understanding of the physics of dilute plas- mas. Furthermore, by moving metals and thermal energy through the cluster, convection may change the cooling rate of the gas and thus significantly impact the process of galaxy formation. Cluster convection also impacts the use of clusters as cosmological probes. Convection may drive turbulence in clusters with mean Mach numbers of order-unity. This changes the force balance in clusters, decreasing the thermal energy of a cluster of a given mass. Current methods for using clusters to constrain dark energy rely on observational probes of the thermal energy as a proxy for total mass. The accuracy of these methods depends on how vigorous cluster convection is. Chapter 3 studies thermal instability in galaxy clusters. I argue that clusters are all likely to be thermally unstable, but that this instability only grows to large amplitude in a subset of systems. Later studies have applied this result to galaxy formation in clusters and shown that one can reproduce some features of the well-known non-self-similarity at the high mass end of the galaxy luminosity function. Chapters 4 and 5 extends my work on convection (and, eventually, thermal instability) to consider the cosmological context of galaxy formation. This work aims to remove any arbitrary initial and boundary conditions from my simulations and is an important step toward a self-consistent model for the plasma physics in clusters.

Using Dark Matter Haloes to Learn about Cosmic Acceleration: A New Proposal for a Universal Mass Function

NASA Technical Reports Server (NTRS)

Prescod-Weinstein, Chanda; Afshordi, Niayesh

2011-01-01

Structure formation provides a strong test of any cosmic acceleration model because a successful dark energy model must not inhibit or overpredict the development of observed large-scale structures. Traditional approaches to studies of structure formation in the presence of dark energy or a modified gravity implement a modified Press-Schechter formalism, which relates the linear overdensities to the abundance of dark matter haloes at the same time. We critically examine the universality of the Press-Schechter formalism for different cosmologies, and show that the halo abundance is best correlated with spherical linear overdensity at 94% of collapse (or observation) time. We then extend this argument to ellipsoidal collapse (which decreases the fractional time of best correlation for small haloes), and show that our results agree with deviations from modified Press-Schechter formalism seen in simulated mass functions. This provides a novel universal prescription to measure linear density evolution, based on current and future observations of cluster (or dark matter) halo mass function. In particular, even observations of cluster abundance in a single epoch will constrain the entire history of linear growth of cosmological of perturbations.

A novel quantification-driven proteomic strategy identifies an endogenous peptide of pleiotrophin as a new biomarker of Alzheimer's disease.

PubMed

Skillbäck, Tobias; Mattsson, Niklas; Hansson, Karl; Mirgorodskaya, Ekaterina; Dahlén, Rahil; van der Flier, Wiesje; Scheltens, Philip; Duits, Floor; Hansson, Oskar; Teunissen, Charlotte; Blennow, Kaj; Zetterberg, Henrik; Gobom, Johan

2017-10-17

We present a new, quantification-driven proteomic approach to identifying biomarkers. In contrast to the identification-driven approach, limited in scope to peptides that are identified by database searching in the first step, all MS data are considered to select biomarker candidates. The endopeptidome of cerebrospinal fluid from 40 Alzheimer's disease (AD) patients, 40 subjects with mild cognitive impairment, and 40 controls with subjective cognitive decline was analyzed using multiplex isobaric labeling. Spectral clustering was used to match MS/MS spectra. The top biomarker candidate cluster (215% higher in AD compared to controls, area under ROC curve = 0.96) was identified as a fragment of pleiotrophin located near the protein's C-terminus. Analysis of another cohort (n = 60 over four clinical groups) verified that the biomarker was increased in AD patients while no change in controls, Parkinson's disease or progressive supranuclear palsy was observed. The identification of the novel biomarker pleiotrophin 151-166 demonstrates that our quantification-driven proteomic approach is a promising method for biomarker discovery, which may be universally applicable in clinical proteomics.

Shedding Light on the Cosmic Skeleton

NASA Astrophysics Data System (ADS)

2009-11-01

Astronomers have tracked down a gigantic, previously unknown assembly of galaxies located almost seven billion light-years away from us. The discovery, made possible by combining two of the most powerful ground-based telescopes in the world, is the first observation of such a prominent galaxy structure in the distant Universe, providing further insight into the cosmic web and how it formed. "Matter is not distributed uniformly in the Universe," says Masayuki Tanaka from ESO, who led the new study. "In our cosmic vicinity, stars form in galaxies and galaxies usually form groups and clusters of galaxies. The most widely accepted cosmological theories predict that matter also clumps on a larger scale in the so-called 'cosmic web', in which galaxies, embedded in filaments stretching between voids, create a gigantic wispy structure." These filaments are millions of light years long and constitute the skeleton of the Universe: galaxies gather around them, and immense galaxy clusters form at their intersections, lurking like giant spiders waiting for more matter to digest. Scientists are struggling to determine how they swirl into existence. Although massive filamentary structures have been often observed at relatively small distances from us, solid proof of their existence in the more distant Universe has been lacking until now. The team led by Tanaka discovered a large structure around a distant cluster of galaxies in images they obtained earlier. They have now used two major ground-based telescopes to study this structure in greater detail, measuring the distances from Earth of over 150 galaxies, and, hence, obtaining a three-dimensional view of the structure. The spectroscopic observations were performed using the VIMOS instrument on ESO's Very Large Telescope and FOCAS on the Subaru Telescope, operated by the National Astronomical Observatory of Japan. Thanks to these and other observations, the astronomers were able to make a real demographic study of this structure, and have identified several groups of galaxies surrounding the main galaxy cluster. They could distinguish tens of such clumps, each typically ten times as massive as our own Milky Way galaxy - and some as much as a thousand times more massive - while they estimate that the mass of the cluster amounts to at least ten thousand times the mass of the Milky Way. Some of the clumps are feeling the fatal gravitational pull of the cluster, and will eventually fall into it. "This is the first time that we have observed such a rich and prominent structure in the distant Universe," says Tanaka. "We can now move from demography to sociology and study how the properties of galaxies depend on their environment, at a time when the Universe was only two thirds of its present age." The filament is located about 6.7 billion light-years away from us and extends over at least 60 million light-years. The newly uncovered structure does probably extend further, beyond the field probed by the team, and hence future observations have already been planned to obtain a definite measure of its size. More information This research was presented in a paper published as a letter in the Astronomy & Astrophysics Journal: The spectroscopically confirmed huge cosmic structure at z = 0.55, by Tanaka et al. The team is composed of Masayuki Tanaka (ESO), Alexis Finoguenov (Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany and University of Maryland, Baltimore, USA), Tadayuki Kodama (National Astronomical Observatory of Japan, Tokyo, Japan), Yusei Koyama (Department of Astronomy, University of Tokyo, Japan), Ben Maughan (H.H. Wills Physics Laboratory, University of Bristol, UK) and Fumiaki Nakata (Subaru Telescope, National Astronomical Observatory of Japan). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

Quasars, clusters and cosmology

NASA Astrophysics Data System (ADS)

Dhanda, Neelam

PART A: Acceleration of the Universe and Modified Gravity: We study the power of next-generation galaxy cluster surveys (such as eROSITA and WFXT) in constraining the cosmological parameters and especially the growth history of the Universe, using the information from galaxy cluster redshift and mass-function evolution and from cluster power spectrum. We use the Fisher Matrix formalism to evaluate the potential for the galaxy cluster surveys to make predictions about cosmological parameters like the gravitational growth index gamma. The primary purpose of this study has been to check whether we can rule out one or the other of the underlying gravity theories in light of the present uncertainty of mass-observable relations and their scatter evolution. We found that these surveys will provide better constraints on various cosmological parameters even after we admit a lack of complete knowledge about the galaxy cluster structure, and when we combine the information from the cluster number count redshift and mass evolution with that from the cluster power spectrum. Based on this, we studied the ability of different surveys to constrain the growth history of the Universe. It was found that whereas eROSITA surveys will need strong priors on cluster structure evolution to conclusively rule out one or the other of the two gravity models, General Relativity and DGP Braneworld Gravity; WFXT surveys do hold the special promise of differentiating growth and telling us whether it is GR or not, with its wide-field survey having the ability to say so even with 99% confidence. PART B: Chemical Evolution in Quasars: We studied chemical evolution in the broad emission line region (BELR) of nitrogen rich quasars drawn from the SDSS Quasar Catalogue IV. Using tools of emission-line spectroscopy, we made detailed abundance measurements of ˜ 40 quasars and estimated their metallicities using the line-intensity ratio method. It was found that quasars with strong nitrogen lines are indicators of high metallicities. Some of these quasars have reached metallicities as high as Z ˜ 20 Z⊙ . Our detailed analysis showed that except in three QSOs, most of the different line-intensity ratios implied the similar metallicities. This verifies that this abundance analysis technique does produce meaningful results. The exceptions are the line-intensity ratio NIV]/CIV, which gives systematically low metallicities and the line-intensity ratio NV/He II, which gives systematically high metallicities. We compared our findings with the predictions of the galactic chemical evolution models. From this study it was concluded that such high metallicities are reached either by requiring a top-heavy Initial Mass Function (IMF) for the quasar host galaxy as suggested by theoretical models, or by physically catastrophic events such as mergers that trigger star formation in already evolved systems which then leads to extreme metallicities in such quasars.

Cross-border outbreak of extensively drug-resistant tuberculosis linked to a university in Romania.

PubMed

Popovici, O; Monk, Ph; Chemtob, D; Chiotan, D; Freidlin, P J; Groenheit, R; Haanperä, M; Homorodean, D; Mansjö, M; Robinson, E; Rorman, E; Smith, G; Soini, H; Van Der Werf, M J

2018-05-01

Extensively drug-resistant (XDR) tuberculosis (TB) poses a threat to public health due to its complicated, expensive and often unsuccessful treatment. A cluster of three XDR TB cases was detected among foreign medical students of a Romanian university. The contact investigations included tuberculin skin testing or interferon gamma release assay, chest X-ray, sputum smear microscopy, culture, drug susceptibility testing, genotyping and whole-genome sequencing (WGS), and were addressed to students, personnel of the university, family members or other close contacts of the cases. These investigations increased the total number of cases to seven. All confirmed cases shared a very similar WGS profile. Two more cases were epidemiologically linked, but no laboratory confirmation exists. Despite all the efforts done, the source of the outbreak was not identified, but the transmission was controlled. The investigation was conducted by a team including epidemiologists and microbiologists from five countries (Finland, Israel, Romania, Sweden and the UK) and from the European Centre for Disease Prevention and Control. Our report shows how countries can collaborate to control the spread of XDR TB by exchanging information about cases and their contacts to enable identification of additional cases and transmission and to perform the source investigation.

Entropy-based consensus clustering for patient stratification.

PubMed

Liu, Hongfu; Zhao, Rui; Fang, Hongsheng; Cheng, Feixiong; Fu, Yun; Liu, Yang-Yu

2017-09-01

Patient stratification or disease subtyping is crucial for precision medicine and personalized treatment of complex diseases. The increasing availability of high-throughput molecular data provides a great opportunity for patient stratification. Many clustering methods have been employed to tackle this problem in a purely data-driven manner. Yet, existing methods leveraging high-throughput molecular data often suffers from various limitations, e.g. noise, data heterogeneity, high dimensionality or poor interpretability. Here we introduced an Entropy-based Consensus Clustering (ECC) method that overcomes those limitations all together. Our ECC method employs an entropy-based utility function to fuse many basic partitions to a consensus one that agrees with the basic ones as much as possible. Maximizing the utility function in ECC has a much more meaningful interpretation than any other consensus clustering methods. Moreover, we exactly map the complex utility maximization problem to the classic K -means clustering problem, which can then be efficiently solved with linear time and space complexity. Our ECC method can also naturally integrate multiple molecular data types measured from the same set of subjects, and easily handle missing values without any imputation. We applied ECC to 110 synthetic and 48 real datasets, including 35 cancer gene expression benchmark datasets and 13 cancer types with four molecular data types from The Cancer Genome Atlas. We found that ECC shows superior performance against existing clustering methods. Our results clearly demonstrate the power of ECC in clinically relevant patient stratification. The Matlab package is available at http://scholar.harvard.edu/yyl/ecc . yunfu@ece.neu.edu or yyl@channing.harvard.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hua, Xiu-Ni; Qin, Lan; Yan, Xiao-Zhi

Hydrothermal reactions of N-auxiliary flexible exo-bidentate ligand 1,3-bis(4-pyridyl)propane (bpp) and carboxylates ligands naphthalene-2,6-dicarboxylic acid (2,6-H{sub 2}ndc) or 4,4′-(hydroxymethylene)dibenzoic acid (H{sub 2}hmdb), in the presence of cadmium(II) salts have given rise to two novel metal-organic frameworks based on flexible ligands (FL-MOFs), namely, [Cd{sub 2}(2,6-ndc){sub 2}(bpp)(DMF)]·2DMF (1) and [Cd{sub 3}(hmdb){sub 3}(bpp)]·2DMF·2EtOH (2) (DMF=N,N-Dimethylformamide). Single-crystal X-ray diffraction analyses revealed that compound 1 exhibits a three-dimensional self-penetrating 6-connected framework based on dinuclear cluster second building unit. Compound 2 displays an infinite three-dimensional ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster and V-shaped organic linkers. The flexible bpp ligand displays different conformations inmore » 1 and 2, which are successfully controlled by size-matching mixed ligands during the self-assembly process. - Graphical abstract: Compound 1 exhibits a 3D self-penetrating 6-connected framework based on dinuclear cluster, and 2 displays an infinite 3D ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster. The flexible 1,3-bis(4-pyridyl)propane ligand displays different conformations in 1 and 2, which successfully controlled by size-matching mixed ligands during the self-assembly process.« less

A Comparison of I.H.E. Faculty, L.E.A. Faculty, and I.H.E. Student Perceptions of Select Teacher Competencies.

ERIC Educational Resources Information Center

Staszkiewicz, Mark J.; Gabrys, Robert E.

Noting that a major problem confronting competency based teacher education (CBTE) programs was the development of mutually acceptable perceptions of teacher education among college faculty, school personnel, and prospective teachers, a cluster of competencies developed by the State University College at Oneonta (SUCO), New York, was critiqued by…

Hypersexuality and high sexual desire: exploring the structure of problematic sexuality.

PubMed

Carvalho, Joana; Štulhofer, Aleksandar; Vieira, Armando L; Jurin, Tanja

2015-06-01

The concept of hypersexuality has been accompanied by fierce debates and conflicting conclusions about its nature. One of the central questions under the discussion is a potential overlap between hypersexuality and high sexual desire. With the relevant research in its early phase, the structure of hypersexuality remains largely unknown. The aim of the present study was to systematically explore the overlap between problematic sexuality and high sexual desire. A community online survey was carried out in Croatia in 2014. The data were first cluster analyzed (by gender) based on sexual desire, sexual activity, perceived lack of control over one's sexuality, and negative behavioral consequences. Participants in the meaningful clusters were then compared for psychosocial characteristics. To complement cluster analysis (CA), multigroup confirmatory factor analysis (CFA) of the same four constructs was carried out. Indicators representing the proposed structure of hypersexuality were included: sexual desire, frequency of sexual activity, lack of control over one's sexuality, and negative behavioral outcomes. Psychosocial characteristics such as religiosity, attitudes toward pornography, and general psychopathology were also evaluated. CA pointed to the existence of two meaningful clusters, one representing problematic sexuality, that is, lack of control over one's sexuality and negative outcomes (control/consequences cluster), and the other reflecting high sexual desire and frequent sexual activity (desire/activity cluster). Compared with the desire/activity cluster, individuals from the control/consequences cluster reported more psychopathology and were characterized by more traditional attitudes. Complementing the CA findings, CFA pointed to two distinct latent dimensions-problematic sexuality and high sexual desire/activity. Our study supports the distinctiveness of hypersexuality and high sexual desire/activity, suggesting that problematic sexuality might be more associated with the perceived lack of personal control over sexuality and moralistic attitudes than with high levels of sexual desire and activity. © 2015 International Society for Sexual Medicine.

CALL FOR PAPERS: Special cluster issue on `Experimental studies of zonal flow and turbulence'

NASA Astrophysics Data System (ADS)

Itoh, S.-I.

2005-07-01

Plasma Physics and Controlled Fusion (PPCF) invites submissions on the topic of `Experimental studies of zonal flow and turbulence', for consideration for a special topical cluster of articles to be published early in 2006. The topical cluster will be published in an issue of PPCF, combined with regular articles. The Guest Editor for the special cluster will be S-I Itoh, Kyushu University, Japan. There has been remarkable progress in the area of structure formation by turbulence. One of the highlights has been the physics of zonal flow and drift wave turbulence in toroidal plasmas. Extensive theoretical as well as computational studies have revealed the various mechanisms in turbulence and zonal flows. At the same time, experimental research on the zonal flow, geodesic acoustic modes and generation of global electric field by turbulence has evolved rapidly. Fast growth in reports of experimental results has stimulated further efforts to develop increased knowledge and systematic understanding. Each paper considered for the special cluster should describe the present research status and new scientific knowledge/results from the authors on experimental studies of zonal flow, geodesic acoustic modes and generation of electric field by turbulence (including studies of Reynolds-Maxwell stresses, etc). Manuscripts submitted to this special cluster in Plasma Physics and Controlled Fusion will be refereed according to the normal criteria and procedures of the journal. The Guest Editor guides the progress of the cluster from the initial open call, through the standard refereeing process, to publication. To be considered for inclusion in the special cluster, articles must be submitted by 2 September 2005 and must clearly state `for inclusion in the Turbulent Plasma Cluster'. Articles submitted after this deadline may not be included in the cluster issue but may be published in a later issue of the journal. Please submit your manuscript electronically via our web site at www.iop.org/journals/ppcf or by e-mail to mailto:ppcf@iop.org. Electronic submissions are encouraged but if you wish to submit a hard copy of your article then please send your typescript, a set of original figures and a covering letter to: The Publishing Administrator Plasma Physics and Controlled Fusion Institute of Physics Publishing Dirac House Temple Back Bristol BS1 6BE UK Further information on how to submit may be obtained on request by e-mailing the journal at the above address. Alternatively, visit the homepage of the journal (www.iop.org/journals/ppcf).

Modular and hierarchical structure of social contact networks

NASA Astrophysics Data System (ADS)

Ge, Yuanzheng; Song, Zhichao; Qiu, Xiaogang; Song, Hongbin; Wang, Yong

2013-10-01

Social contact networks exhibit overlapping qualities of communities, hierarchical structure and spatial-correlated nature. We propose a mixing pattern of modular and growing hierarchical structures to reconstruct social contact networks by using an individual’s geospatial distribution information in the real world. The hierarchical structure of social contact networks is defined based on the spatial distance between individuals, and edges among individuals are added in turn from the modular layer to the highest layer. It is a gradual process to construct the hierarchical structure: from the basic modular model up to the global network. The proposed model not only shows hierarchically increasing degree distribution and large clustering coefficients in communities, but also exhibits spatial clustering features of individual distributions. As an evaluation of the method, we reconstruct a hierarchical contact network based on the investigation data of a university. Transmission experiments of influenza H1N1 are carried out on the generated social contact networks, and results show that the constructed network is efficient to reproduce the dynamic process of an outbreak and evaluate interventions. The reproduced spread process exhibits that the spatial clustering of infection is accordant with the clustering of network topology. Moreover, the effect of individual topological character on the spread of influenza is analyzed, and the experiment results indicate that the spread is limited by individual daily contact patterns and local clustering topology rather than individual degree.

Evolution of the early-type galaxy fraction in clusters since z = 0.8

NASA Astrophysics Data System (ADS)

Simard, L.; Clowe, D.; Desai, V.; Dalcanton, J. J.; von der Linden, A.; Poggianti, B. M.; White, S. D. M.; Aragón-Salamanca, A.; De Lucia, G.; Halliday, C.; Jablonka, P.; Milvang-Jensen, B.; Saglia, R. P.; Pelló, R.; Rudnick, G. H.; Zaritsky, D.

2009-12-01

We study the morphological content of a large sample of high-redshift clusters to determine its dependence on cluster mass and redshift. Quantitative morphologies are based on PSF-convolved, 2D bulge+disk decompositions of cluster and field galaxies on deep Very Large Telescope FORS2 images of eighteen, optically-selected galaxy clusters at 0.45 < z < 0.80 observed as part of the ESO Distant Cluster Survey (“EDisCS”). Morphological content is characterized by the early-type galaxy fraction f_et, and early-type galaxies are objectively selected based on their bulge fraction and image smoothness. This quantitative selection is equivalent to selecting galaxies visually classified as E or S0. Changes in early-type fractions as a function of cluster velocity dispersion, redshift and star-formation activity are studied. A set of 158 clusters extracted from the Sloan Digital Sky Survey is analyzed exactly as the distant EDisCS sample to provide a robust local comparison. We also compare our results to a set of clusters from the Millennium Simulation. Our main results are: (1) the early-type fractions of the SDSS and EDisCS clusters exhibit no clear trend as a function of cluster velocity dispersion. (2) Mid-z EDisCS clusters around σ = 500 km s-1 have f_et ≃ 0.5 whereas high-z EDisCS clusters have f_et ≃ 0.4. This represents a ~25% increase over a time interval of 2 Gyr. (3) There is a marked difference in the morphological content of EDisCS and SDSS clusters. None of the EDisCS clusters have early-type galaxy fractions greater than 0.6 whereas half of the SDSS clusters lie above this value. This difference is seen in clusters of all velocity dispersions. (4) There is a strong and clear correlation between morphology and star formation activity in SDSS and EDisCS clusters in the sense that decreasing fractions of [OII] emitters are tracked by increasing early-type fractions. This correlation holds independent of cluster velocity dispersion and redshift even though the fraction of [OII] emitters decreases from z ˜0.8 to z ˜ 0.06 in all environments. Our results pose an interesting challenge to structural transformation and star formation quenching processes that strongly depend on the global cluster environment (e.g., a dense ICM) and suggest that cluster membership may be of lesser importance than other variables in determining galaxy properties. Based on observations obtained in visitor and service modes at the ESO Very Large Telescope (VLT) as part of the Large Programme 166.A-0162 (the ESO Distant Cluster Survey). Also based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposal 9476. Support for this proposal was provided by NASA through a grant from the Space Telescope Science Institute. Table [see full textsee full textsee full textsee full textsee full text] is only available in electronic form at http://www.aanda.org

Feeling Healthy? A Survey of Physical and Psychological Wellbeing of Students from Seven Universities in the UK

PubMed Central

Ansari, Walid El; Stock, Christiane; Snelgrove, Sherrill; Hu, Xiaoling; Parke, Sian; Davies, Shân; John, Jill; Adetunji, Hamed; Stoate, Mary; Deeny, Pat; Phillips, Ceri; Mabhala, Andi

2011-01-01

University students’ physical and psychological health and wellbeing are important and comprise many variables. This study assessed perceived health status in addition to a range of physical and psychological wellbeing indicators of 3,706 undergraduate students from seven universities in England, Wales and Northern Ireland. We compared differences in these variables across males and females, and across the participating universities. The data was collected in 2007–2008. A self-administered questionnaire assessed socio-demographic information (e.g., gender, age), self-reported physical and psychological health data, as well as questions on health awareness, health service use, social support, burdens and stressors and university study related questions. While females generally reported more health problems and psychological burdens, male students felt that they received/had fewer persons to depend on for social support. The comparisons of health and wellbeing variables across the different universities suggested some evidence of ‘clustering’ of the variables under study, whereby favourable situations would be exhibited by a cluster of the variables that is encountered at some universities; and conversely, the clustering of less favourable variables as exhibited at other universities. We conclude that the level of health complaints and psychological problems/burdens is relatively high and calls for increased awareness of university administrators, leaders and policy makers to the health and well-being needs of their students. The observed clustering effects also indicated the need for local (university-specific) health and wellbeing profiles as basis and guidance for relevant health promotion programmes at universities. PMID:21655121

Psychiatric Comorbidity Among Egyptian Patients With Opioid Use Disorders Attributed to Tramadol.

PubMed

Bassiony, Medhat M; Youssif, Usama M; Hussein, Ramadan A; Saeed, Mervat

2016-01-01

Opioid use disorders attributed to tramadol (OUD-T) is a public health problem in Egypt. The objective of this study was to assess the psychiatric comorbidity among patients with opioid use disorder attributed to tramadol. This study included 100 patients with opioid use disorders attributed to tramadol (according to DSM-IV-TR) and 100 control persons (matched for age, sex, and education), who were recruited from Zagazig University Hospital, Egypt. The participants were interviewed using Structured Clinical Interview for DSM disorders (SCID-I and SCID-II), Addiction Severity Index scale (patients), and urine screening for drugs. Twenty-four percent of the patients used tramadol only (pure tramadol group), whereas 76% of the patients used other substances in addition to tramadol (polysubstance group). Most (91%) of the patients had tramadol dependence. Forty-nine percent of the patients had psychiatric comorbidity, especially mood disorders (59.2%), whereas only 24% of the control persons had psychiatric comorbidity, especially anxiety disorders (83.3%). The most common personality disorders among patients were borderline (24%) and antisocial (22%), whereas in control persons, the most common personality disorders were obsessive compulsive personality disorder (8%) and the avoidant personality disorder (7%). Cluster B (76.6%) was the most common category among patients (compared with 25.8% in control persons), whereas cluster C (51.6%) was the most common category among control persons (compared with 15.6% in patients). Most of the patients were dependent on tramadol, and approximately 3 out of 4 used many substances. Almost half of the patients had psychiatric comorbidity, and approximately 3 out of 4 had cluster B personality disorders.

An assessment of health behavior peer effects in Peking University dormitories: a randomized cluster-assignment design for interference.

PubMed

Yuan, Changzheng; Lv, Jun; VanderWeele, Tyler J

2013-01-01

Relatively little is known about the peer influence in health behaviors within university dormitory rooms. Moreover, in China, the problem of unhealthy behaviors among university students has not yet been sufficiently recognized. We thus investigated health behavior peer influence in Peking University dormitories utilizing a randomized cluster-assignment design. Cross-sectional in-dormitory survey. Current students from Peking University Health Science Center from April to June, 2009. Self-reported questionnaire on health behaviors: physical activity (including bicycling), dietary intake and tobacco use. Use of bicycle, moderate-intensity exercise, frequency of sweet food and soybean milk intake, frequency of roasted/baked/toasted food intake were behaviors significantly or marginally significantly affected by peer influence. Health behavior peer effects exist within dormitory rooms among university students. This could provide guidance on room assignment, or inform intervention programs. Examining these may demand attention from university administrators and policy makers.

How Clusters Work

EPA Pesticide Factsheets

Technology innovation clusters are geographic concentrations of interconnected companies, universities, and other organizations with a focus on environmental technology. They play a key role in addressing the nation’s pressing environmental problems.

The NGC 4839 group falling into the Coma cluster observed by XMM-Newton

NASA Astrophysics Data System (ADS)

Neumann, D. M.; Arnaud, M.; Gastaud, R.; Aghanim, N.; Lumb, D.; Briel, U. G.; Vestrand, W. T.; Stewart, G. C.; Molendi, S.; Mittaz, J. P. D.

2001-01-01

We present here the first analysis of the XMM-Newton EPIC-MOS data of the galaxy group around NGC 4839, which lies at a projected distance to the Coma cluster center of 1.6h50-1 Mpc. In our analysis, which includes imaging, spectro-imaging and spectroscopy we find compelling evidence for the sub group being on its first infall onto the Coma cluster. The complex temperature structure around NGC 4839 is consistent with simulations of galaxies falling into a cluster environment. We see indications of a bow shock and of ram pressure stripping around NGC 4839. Furthermore our data reveal a displacement between NGC 4839 and the center of the hot gas in the group of about 300h50-1 kpc. With a simple approximation we can explain this displacement by the pressure force originating from the infall, which acts much stronger on the group gas than on the galaxies. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). EPIC was developed by the EPIC Consortium led by the Principal Investigator, Dr. M. J. L. Turner. The consortium comprises the following Institutes: University of Leicester, University of Birmingham, (UK); CEA/Saclay, IAS Orsay, CESR Toulouse, (France); IAAP Tuebingen, MPE Garching, (Germany); IFC Milan, ITESRE Bologna, IAUP Palermo, Italy. EPIC is funded by: PPARC, CEA, CNES, DLR and ASI.

Variable Stars in Large Magellanic Cloud Globular Clusters. II. NGC 1786

NASA Astrophysics Data System (ADS)

Kuehn, Charles A.; Smith, Horace A.; Catelan, Márcio; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2012-12-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B-V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Inhomogeneous cosmology and backreaction: Current status and future prospects

NASA Astrophysics Data System (ADS)

Bolejko, Krzysztof; Korzyński, Mikołaj

Astronomical observations reveal hierarchical structures in the universe, from galaxies, groups of galaxies, clusters and superclusters, to filaments and voids. On the largest scales, it seems that some kind of statistical homogeneity can be observed. As a result, modern cosmological models are based on spatially homogeneous and isotropic solutions of the Einstein equations, and the evolution of the universe is approximated by the Friedmann equations. In parallel to standard homogeneous cosmology, the field of inhomogeneous cosmology and backreaction is being developed. This field investigates whether small scale inhomogeneities via nonlinear effects can backreact and alter the properties of the universe on its largest scales, leading to a non-Friedmannian evolution. This paper presents the current status of inhomogeneous cosmology and backreaction. It also discusses future prospects of the field of inhomogeneous cosmology, which is based on a survey of 50 academics working in the field of inhomogeneous cosmology.

J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

NASA Astrophysics Data System (ADS)

Schirmer, M.; Suyu, S.; Schrabback, T.; Hildebrandt, H.; Erben, T.; Halkola, A.

2010-05-01

Aims: We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. Methods: We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data. Results: J0454 is located at z = 0.26, with a gap of 2.5 mag between the brightest and second brightest galaxies within half the virial radius. Outside a radius of 1.5 Mpc, we find two filaments extending over 4 Mpc, and within we identify 31 members spectroscopically and 33 via the red sequence with i < 22 mag. They segregate into spirals (σ_v = 590 km s-1) and a central concentration of ellipticals (σ_v = 480 km s-1), establishing a morphology-density relation. Weak lensing and cluster richness relations yield consistent values of r200 = 810-850 kpc and M200 = (0.75-0.90) × 1014 M_⊙. The brightest group galaxy (BGG) is inconsistent with the dynamic centre of J0454. It strongly lenses a galaxy at z = 2.1 ± 0.3, and we model the lens with a pseudo-isothermal elliptical mass distribution. A high external shear, and a discrepancy between the Einstein radius and the weak lensing velocity dispersion requires that the BGG must be offset from J0454's dark halo centre by at least 90-130 kpc. The X-ray halo is offset by 24 ± 16 kpc from the BGG, shows no signs of a cooling flow and can be fit by a single β-model. With LX = (1.4 ± 0.2) × 1043 erg s-1 J0454 falls onto standard cluster scaling relations, but appears cooler (T = 1.1 ± 0.1 keV) than expected (T ~ 2.0 keV). Taken all together, these data indicate that J0454 consists of two systems, a sparse cluster and an infalling fossil group, where the latter seeds the brightest cluster galaxy. An alternative to the sparse cluster could be a filament projected along the line of sight mimicking a cluster, with galaxies streaming towards the fossil group. This work is based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; based on observations made with ESO Telescopes at the La Silla and Paranal Observatories, Chile (ESO DDT Programme 282.A-5066); based on observations made with the NASA/ESA Hubble Space Telescope (programme #9836) obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555; based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.