Debating Sex: Education Films and Sexual Morality for the Young in post-War Germany, 1945-55

PubMed Central

Winkler, Anita

2015-01-01

Summary After 1945 rapidly climbing figures of venereal disease infections menaced the health of the war-ridden German population. Physicians sought to gain control over this epidemic and initiated large-scale sex education campaigns to inform people about identification, causes and treatment of VD and advised them on appropriate moral sexual behaviour as a prophylactic measure. Film played a crucial role in these campaigns. As mass medium it was believed film could reach out to large parts of society and quickly disseminate sexual knowledge and moral codes of conduct amongst the population. This essay discusses the transition of the initial central role of sex education films in the fight against venereal disease in the immediate post-war years towards a more critical stance as to the effects of cinematographic education of the young in an East and West German context. PMID:26403056

The Impact of Accelerating Faster than Exponential Population Growth on Genetic Variation

PubMed Central

Reppell, Mark; Boehnke, Michael; Zöllner, Sebastian

2014-01-01

Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models’ effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times. PMID:24381333

The impact of accelerating faster than exponential population growth on genetic variation.

PubMed

Reppell, Mark; Boehnke, Michael; Zöllner, Sebastian

2014-03-01

Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models' effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times.

Lightning Channel Corona Formation Treated as a Large System of Streamers

NASA Astrophysics Data System (ADS)

Carlson, B.; Lehtinen, N. G.; Kochkin, P.

2017-12-01

Transfer of charge along a lightning channel leads to strong electric fields that drive such charge outward. This charge flow is nonuniform, breaking up into millimeter-scale discharge structures called streamers. The motion of such streamers can carry charge many meters outward from the channel, but each individual streamer only carries a small amount of charge. Transfer of macroscopic charge outward thus requires a large population of streamers that are expected to interact and exhibit interesting collective behaviors. We attempt to simulate such collective behaviors by approximating the behavior of each streamer but retaining streamer interactions and overall electrodynamic effects and apply this simulation to a few key scenarios. For the case of flow of charge off a lightning channel, we simulate a continually growing population of streamers injected near a charged conducting channel. Further, motivated by lightning initiation, we simulate the growth of a population of streamers from a single seed streamer as might initiate from a hydrometeor. For all cases considered, we characterize the charges and currents involved, compare to observations where possible, and characterize the collective effects including spatial and temporal non-uniformity.

Determinants of Police Strength in Large U.S. Cities during the 1990s: A Fixed-Effects Panel Analysis

ERIC Educational Resources Information Center

McCarty, William P.; Ren, Ling; Zhao, Jihong

2012-01-01

The 1990s represented a unique decade in which to analyze the determinants of police strength in the United States. This decade was a time in which crime initially increased, then substantially decreased. Furthermore, this decade also was characterized by increases in the minority population throughout large American cities. Finally, the 1990s…

MONITORING DECLINING METAPOPULATIONS: INSIGHTS FROM A MODEL SIMULATION

EPA Science Inventory

Pond-breeding amphibians, host-specialist butterflies, and a variety of other organisms have been shown to exhibit population structures and dynamics consistent with metapopulation theory. In recent years large-scale biodiversity monitoring efforts have been initiated in many reg...

Hydroxyurea effectiveness in children and adolescents with sickle cell anemia: A large retrospective, population-based cohort.

PubMed

Quarmyne, Maa-Ohui; Dong, Wei; Theodore, Rodney; Anand, Sonia; Barry, Vaughn; Adisa, Olufolake; Buchanan, Iris D; Bost, James; Brown, Robert C; Joiner, Clinton H; Lane, Peter A

2017-01-01

The clinical efficacy of hydroxyurea in patients with sickle cell anemia (SCA) has been well established. However, data about its clinical effectiveness in practice is limited. We evaluated the clinical effectiveness of hydroxyurea in a large pediatric population using a retrospective cohort, pre-post treatment study design to control for disease severity selection bias. The cohort included children with SCA (SS, Sβ 0 thalassemia) who received care at Children's Healthcare of Atlanta (CHOA) and who initiated hydroxyurea in 2009-2011. Children on chronic transfusions, or children with inadequate follow up data and/or children who had taken hydroxyurea in the 3 years prior were excluded. For each patient healthcare utilization, laboratory values, and clinical outcomes for the 2-year period prior to hydroxyurea initiation were compared to those 2 years after initiation. Of 211 children with SCA who initiated hydroxyurea in 2009-2011, 134 met eligibility criteria. After initiation of hydroxyurea, rates of hospitalizations, pain encounters, and emergency department visits were reduced by 47% (<0.0001), 36% (P = 0.0001) and 43% (P < 0.0001), respectively. Average hemoglobin levels increased by 0.7 g/dl (P < 0.0001). Hydroxyurea effectiveness was similar across gender, insurance types and age, although there was a slightly greater reduction in hospitalizations in younger children. Am. J. Hematol. 92:77-81, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Increasing the health promotion practices of workplaces in Australia with a proactive telephone-based intervention.

PubMed

Daly, Justine; Licata, Milly; Gillham, Karen; Wiggers, John

2005-01-01

The aim of this study was to explore the potential effectiveness of a proactive telephone-based intervention in increasing workplace adoption of health promotion initiatives. A telephone-based direct marketing strategy was used to contact a sample of Australian workplaces to encourage the adoption of health promotion initiatives. Workplaces were offered free services and resources designed to facilitate adoption of health promotion initiatives. A total of 227 (71%) workplaces provided informed consent to participate in both baseline and 4-year follow-up surveys. Significant increases were evident for seven of the eight health promotion initiatives. The findings of this study suggest that a proactive telephone-based intervention has the potential to be effective in increasing the prevalence of health promotion initiatives across a range of health topics in a large population of workplaces. Given the capacity to reach an entire population of workplaces, this approach represents a promising means of achieving the established potential of workplace health promotion.

Application of “Systems Vaccinology” to Evaluate Inflammation and Reactogenicity of Adjuvanted Preventative Vaccines

PubMed Central

Lewis, David J. M.; Lythgoe, Mark P.

2015-01-01

Advances in “omics” technology (transcriptomics, proteomics, metabolomics, genomics/epigenomics, etc.) allied with statistical and bioinformatics tools are providing insights into basic mechanisms of vaccine and adjuvant efficacy or inflammation/reactogenicity. Predictive biomarkers of relatively frequent inflammatory reactogenicity may be identified in systems vaccinology studies involving tens or hundreds of participants and used to screen new vaccines and adjuvants in in vitro, ex vivo, animal, or human models. The identification of rare events (such as those observed with initial rotavirus vaccine or suspected autoimmune complications) will require interrogation of large data sets and population-based research before application of systems vaccinology. The Innovative Medicine Initiative funded public-private project BIOVACSAFE is an initial attempt to systematically identify biomarkers of relatively common inflammatory events after adjuvanted immunization using human, animal, and population-based models. Discriminatory profiles or biomarkers are being identified, which require validation in large trials involving thousands of participants before they can be generalized. Ultimately, it is to be hoped that the knowledge gained from such initiatives will provide tools to the industry, academia, and regulators to select optimal noninflammatory but immunogenic and effective vaccine adjuvant combinations, thereby shortening product development cycles and identifying unsuitable vaccine candidates that would fail in expensive late stage development or postmarketing. PMID:26380327

Conditions that impact artificial hybridization of Arachis hypogaea L.

USDA-ARS?s Scientific Manuscript database

Modern farming is dependent on continual development of improved cultivars and efficient cultural management practices. In addition, dissecting genetic components of heritable traits also relies on the development of large mapping populations. Artificial hybridization is the critical initial step ...

A Case Study Examining Undergraduate Public Health Student Experiences at a Large, Private, Urban Research University

ERIC Educational Resources Information Center

Baillie, Colleen P.

2017-01-01

Undergraduate students represent a new but growing population at a school of public (SPH) health at a large, private, urban research university on the East Coast. This SPH has offered a minor in public health since 2010, and a major was initiated in 2014. The school also plans to offer an accelerated bachelor's-to-master's in public health…

Nearly Full Employment Recovery Among South African HIV Patients On Antiretroviral Therapy: Evidence From A Large Population Cohort

PubMed Central

Bor, Jacob; Tanser, Frank; Newell, Marie-Louise; Bärnighausen, Till

2013-01-01

Antiretroviral therapy for HIV may have important economic benefits for patients and their households. We quantified the impact of HIV treatment on employment status among HIV patients in rural South Africa who were enrolled in a public-sector HIV treatment program supported by the U.S. President’s Emergency Plan for AIDS Relief. We linked clinical data from more than 2000 patients in the treatment program with ten years of longitudinal socioeconomic data from a complete community-based population cohort of over 30,000 adults residing in the clinical catchment area. We estimated the employment effects of HIV treatment in fixed effects regressions. Four years after the initiation of antiretroviral therapy, employment among HIV patients had recovered to about 90 percent of baseline rates observed in the same patients three to five years before they started treatment. Many patients initiated treatment early enough that they were able to avoid any loss of employment due to HIV. These results represent the first estimates of employment recovery among HIV patients in a general population, relative to the employment levels that these patients had prior to job-threatening illness and the decision to seek care. We find large economic benefits to HIV treatment. For some patients, further gains could be obtained from initiating antiretroviral therapy earlier, prior to HIV-related job loss. PMID:22778335

American Exceptionalism: Population Trends and Flight Initiation Distances in Birds from Three Continents

PubMed Central

Møller, Anders Pape; Samia, Diogo S. M.; Weston, Mike A.; Guay, Patrick-Jean; Blumstein, Daniel T.

2014-01-01

Background All organisms may be affected by humans' increasing impact on Earth, but there are many potential drivers of population trends and the relative importance of each remains largely unknown. The causes of spatial patterns in population trends and their relationship with animal responses to human proximity are even less known. Methodology/Principal Finding We investigated the relationship between population trends of 193 species of bird in North America, Australia and Europe and flight initiation distance (FID); the distance at which birds take flight when approached by a human. While there is an expected negative relationship between population trend and FID in Australia and Europe, we found the inverse relationship for North American birds; thus FID cannot be used as a universal predictor of vulnerability of birds. However, the analysis of the joint explanatory ability of multiple drivers (farmland breeding habitat, pole-most breeding latitude, migratory habit, FID) effects on population status replicated previously reported strong effects of farmland breeding habitat (an effect apparently driven mostly by European birds), as well as strong effects of FID, body size, migratory habit and continent. Farmland birds are generally declining. Conclusions/Significance Flight initiation distance is related to population trends in a way that differs among continents opening new research possibilities concerning the causes of geographic differences in patterns of anti-predator behavior. PMID:25226165

Multi-scale approaches for high-speed imaging and analysis of large neural populations

PubMed Central

Ahrens, Misha B.; Yuste, Rafael; Peterka, Darcy S.; Paninski, Liam

2017-01-01

Progress in modern neuroscience critically depends on our ability to observe the activity of large neuronal populations with cellular spatial and high temporal resolution. However, two bottlenecks constrain efforts towards fast imaging of large populations. First, the resulting large video data is challenging to analyze. Second, there is an explicit tradeoff between imaging speed, signal-to-noise, and field of view: with current recording technology we cannot image very large neuronal populations with simultaneously high spatial and temporal resolution. Here we describe multi-scale approaches for alleviating both of these bottlenecks. First, we show that spatial and temporal decimation techniques based on simple local averaging provide order-of-magnitude speedups in spatiotemporally demixing calcium video data into estimates of single-cell neural activity. Second, once the shapes of individual neurons have been identified at fine scale (e.g., after an initial phase of conventional imaging with standard temporal and spatial resolution), we find that the spatial/temporal resolution tradeoff shifts dramatically: after demixing we can accurately recover denoised fluorescence traces and deconvolved neural activity of each individual neuron from coarse scale data that has been spatially decimated by an order of magnitude. This offers a cheap method for compressing this large video data, and also implies that it is possible to either speed up imaging significantly, or to “zoom out” by a corresponding factor to image order-of-magnitude larger neuronal populations with minimal loss in accuracy or temporal resolution. PMID:28771570

Application of models to conservation planning for terrestrial birds in North America

USGS Publications Warehouse

Fitzgerald, Jane A.; Thogmartin, Wayne E.; Dettmers, Randy; Jones, Tim; Rustay, Christopher; Ruth, Janet M.; Thompson, Frank R.; Will, Tom; Millspaugh, Joshua J.; Thompson, Frank R.

2009-01-01

Partners in Flight (PIF), a public–private coalition for the conservation of land birds, has developed one of four international bird conservation plans recognized under the auspices of the North American Bird Conservation Initiative (NABCI). Partners in Flight prioritized species most in need of conservation attention and set range-wide population goals for 448 species of terrestrial birds. Partnerships are now tasked with developing spatially explicit estimates of the distribution, and abundance of priority species across large ecoregions and identifying habitat acreages needed to support populations at prescribed levels. The PIF Five Elements process of conservation design identifies five steps needed to implement all bird conservation at the ecoregional scale. Habitat assessment and landscape characterization describe the current amounts of different habitat types and summarize patch characteristics, and landscape configurations that define the ability of a landscape to sustain healthy bird populations and are a valuable first step to describing the planning area before pursuing more complex species-specific models. Spatially linked database models, landscape-scale habitat suitability models, and statistical models are viable alternatives for predicting habitat suitability or bird abundance across large planning areas to help assess conservation opportunities, design landscapes to meet population objectives, and monitor change in habitat suitability or bird numbers over time.Bird conservation in the United States is a good example of the use of models in large-scale wildlife conservation planning because of its geographic extent, focus on multiple species, involvement of multiple partners, and use of simple to complex models. We provide some background on the recent development of bird conservation initiatives in the United States and the approaches used for regional conservation assessment and planning. We focus on approaches being used for landscape characterization and assessment, and bird population response modeling.

Convergence to a pulsating travelling wave for an epidemic reaction-diffusion system with non-diffusive susceptible population.

PubMed

Ducrot, Arnaud; Giletti, Thomas

2014-09-01

In this work we study the asymptotic behaviour of the Kermack-McKendrick reaction-diffusion system in a periodic environment with non-diffusive susceptible population. This problem was proposed by Kallen et al. as a model for the spatial spread for epidemics, where it can be reasonable to assume that the susceptible population is motionless. For arbitrary dimensional space we prove that large classes of solutions of such a system have an asymptotic spreading speed in large time, and that the infected population has some pulse-like asymptotic shape. The analysis of the one-dimensional problem is more developed, as we are able to uncover a much more accurate description of the profile of solutions. Indeed, we will see that, for some initially compactly supported infected population, the profile of the solution converges to some pulsating travelling wave with minimal speed, that is to some entire solution moving at a constant positive speed and whose profile's shape is periodic in time.

Risk of population extinction from fixation of deleterious and reverse mutations.

PubMed

Lande, R

1998-01-01

A model is developed for alternate fixations of mildly deleterious and wild-type alleles arising by forward and reverse mutation in a finite population. For almost all parameter values, this gives an equilibrium load that agrees closely with the general expression derived from diffusion theory. Nearly neutral mutations with selection coefficient a few times larger than 1/(2N(e)) do the most damage by increasing the equilibrium load. The model of alternate fixations facilitates dynamical analysis of the expected load and the mean time to extinction in a population that has been suddenly reduced from a very large size to a small size. Reverse mutation can substantially improve population viability, increasing the mean time to extinction by an order of magnitude or more, but because many mutations are irreversible the effects may not be large. Populations with initially high mean fitness and small effective size, N(e) below a few hundred individuals, may be at serious risk of extinction from fixation of deleterious mutations within 10(3) to 10(4) generations.

A Feasibility Experiment for a Soft X-Ray Laser

DTIC Science & Technology

1976-09-01

has embarked on a large scale laser fusion program initially aimed at achieving sufficient thermometric yield from a single pellet to initiate a...gold, aluminum ). The report suggests that 10 to 20 percent of the incident laser energy can be converted to X rays below 1 keV. A Lawrence Livermore...Computa- tions of the population inversion for the inner shell electrons, as found in 3 I-.--I~ . . AFWL-TR-76-107 aluminum , indicate a favorable

Homo- and heterofermentative lactobacilli differently affect sugarcane-based fuel ethanol fermentation

USDA-ARS?s Scientific Manuscript database

The antagonism between by yeast and lactobacilli is largely dependent on the initial population of each organism. While homo-fermentative lactobacillus present higher inhibitory effect upon yeast when in equal cell number, in industrial fuel ethanol conditions where high yeast cell densities prevail...

Phenotypic characterization and genealogical tracing in an Afrikaner schizophrenia database.

PubMed

Karayiorgou, Maria; Torrington, Marie; Abecasis, Gonçalo R; Pretorius, Herman; Robertson, Brian; Kaliski, Sean; Lay, Stephen; Sobin, Christina; Möller, Natalie; Lundy, S Laura; Blundell, Maude L; Gogos, Joseph A; Roos, J Louw

2004-01-01

Founder populations hold tremendous promise for mapping genes for complex traits, as they offer less genetic and environmental heterogeneity and greater potential for genealogical research. Not all founder populations are equally valuable, however. The Afrikaner population meets several criteria that make it an ideal population for mapping complex traits, including founding by a small number of initial founders that likely allowed for a relatively restricted set of mutations and a large current population size that allows identification of a sufficient number of cases. Here, we examine the potential to conduct genealogical research in this population and present initial results indicating that accurate genealogical tracing for up to 17 generations is feasible. We also examine the clinical similarities of schizophrenia cases diagnosed in South Africa and those diagnosed in other, heterogeneous populations, specifically the US. We find that, with regard to basic sample descriptors and cardinal symptoms of disease, the two populations are equivalent. It is, therefore, likely that results from our genetic study of schizophrenia will be applicable to other populations. Based on the results presented here, the history and current size of the population, as well as our previous analysis addressing the extent of background linkage disequilibrium (LD) in the Afrikaners, we conclude that the Afrikaner population is likely an appropriate founder population to map genes for schizophrenia using both linkage and LD approaches. Copyright 2003 Wiley-Liss, Inc.

Promoting Handwashing Behavior: The Effects of Large-scale Community and School-level Interventions.

PubMed

Galiani, Sebastian; Gertler, Paul; Ajzenman, Nicolas; Orsola-Vidal, Alexandra

2016-12-01

This paper analyzes a randomized experiment that uses novel strategies to promote handwashing with soap at critical points in time in Peru. It evaluates a large-scale comprehensive initiative that involved both community and school activities in addition to communication campaigns. The analysis indicates that the initiative was successful in reaching the target audience and in increasing the treated population's knowledge about appropriate handwashing behavior. These improvements translated into higher self-reported and observed handwashing with soap at critical junctures. However, no significant improvements in the health of children under the age of 5 years were observed. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Connection between Dynamically Derived Initial Mass Function Normalization and Stellar Population Parameters

NASA Astrophysics Data System (ADS)

McDermid, Richard M.; Cappellari, Michele; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2014-09-01

We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS3D project. We study trends between our dynamically derived IMF normalization αdyn ≡ (M/L)stars/(M/L)Salp and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [α/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalization of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of αdyn at a given population parameter. As a result, we find weak αdyn-[α/Fe] and αdyn -Age correlations and no significant αdyn -[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalization via the low-mass star demographics inferred through stellar spectral analysis.

Identification of a new stem cell population that generates Drosophila flight muscles.

PubMed

Gunage, Rajesh D; Reichert, Heinrich; VijayRaghavan, K

2014-08-18

How myoblast populations are regulated for the formation of muscles of different sizes is an essentially unanswered question. The large flight muscles of Drosophila develop from adult muscle progenitor (AMP) cells set-aside embryonically. The thoracic segments are all allotted the same small AMP number, while those associated with the wing-disc proliferate extensively to give rise to over 2500 myoblasts. An initial amplification occurs through symmetric divisions and is followed by a switch to asymmetric divisions in which the AMPs self-renew and generate post-mitotic myoblasts. Notch signaling controls the initial amplification of AMPs, while the switch to asymmetric division additionally requires Wingless, which regulates Numb expression in the AMP lineage. In both cases, the epidermal tissue of the wing imaginal disc acts as a niche expressing the ligands Serrate and Wingless. The disc-associated AMPs are a novel muscle stem cell population that orchestrates the early phases of adult flight muscle development.

An Educational Evaluation of Web-Based Forestry Education

ERIC Educational Resources Information Center

Allred, Shorna Broussard; Smallidge, Peter J.

2010-01-01

Online forestry education can serve large populations of woodland owners and managers. Cornell University's ForestConnect program initiated the nation's first woodlot management educational webinar series. We conducted an educational evaluation to determine: (1) the educational impact of the ForestConnect Webinar series, (2) the involvement of new…

Characterizing Air Pollution in Two Low-Income Neighborhoods in Accra, Ghana

EPA Science Inventory

Sub-Saharan Africa has the highest rate of urban population growth in the world, with a large number of urban residents living in low-income “slum” neighborhoods. We conducted a study for an initial assessment of the levels and spatial and/or temporal patterns of multiple polluta...

High prices for rare species can drive large populations extinct: the anthropogenic Allee effect revisited.

PubMed

Holden, Matthew H; McDonald-Madden, Eve

2017-09-21

Consumer demand for plant and animal products threatens many populations with extinction. The anthropogenic Allee effect (AAE) proposes that such extinctions can be caused by prices for wildlife products increasing with species rarity. This price-rarity relationship creates financial incentives to extract the last remaining individuals of a population, despite higher search and harvest costs. The AAE has become a standard approach for conceptualizing the threat of economic markets on endangered species. Despite its potential importance for conservation, AAE theory is based on a simple graphical model with limited analysis of possible population trajectories. By specifying a general class of functions for price-rarity relationships, we show that the classic theory can understate the risk of species extinction. AAE theory proposes that only populations below a critical Allee threshold will go extinct due to increasing price-rarity relationships. Our analysis shows that this threshold can be much higher than the original theory suggests, depending on initial harvest effort. More alarmingly, even species with population sizes above this Allee threshold, for which AAE predicts persistence, can be destined to extinction. Introducing even a minimum price for harvested individuals, close to zero, can cause large populations to cross the classic anthropogenic Allee threshold on a trajectory towards extinction. These results suggest that traditional AAE theory may give a false sense of security when managing large harvested populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stochastic Assembly of Bacteria in Microwell Arrays Reveals the Importance of Confinement in Community Development

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

Hansen, Ryan H.; Timm, Andrea C.; Timm, Collin M.

The structure, function and evolving composition of microbial communities is deeply influenced by the physical and chemical architecture of the local microenvironment. The complexity of this parameter space in naturally occurring systems has made a clear understanding of the key drivers of community development elusive. Here, we examine the role of spatial confinement on community development using a microwell platform that allows for assembly and monitoring of unique microbial communities en masse. This platform was designed to contain microwells with varied size features in order to mimic various levels of spatial confinement found in natural systems. Microbial populations assembled inmore » wells with incrementally smaller size features showed increasingly larger variations in inoculum levels. By exploiting this size dependence, large wells were used to assemble homogenous initial populations of Pseudomonas aeruginosa, allowing for reproducible, directed growth trajectories. In contrast, smaller wells were used to assemble a heterogeneous range of initial populations, resulting in a variety of growth and decay trajectories. This allowed for parallel screening of single member communities across different levels of confinement to identify initial conditions in which P. aeruginosa colonies have dramatically higher probabilities of survival. These results demonstrate a unique approach for manipulating the distribution of initial microbial populations assembled into controlled microenvironments to rapidly identify population and environmental parameters conducive or inhibitive to growth. Additionally, multi-member community assembly was characterized to demonstrate the power of this platform for studying the role of member abundance on microbial competition, mutualism and community succession.« less

Stochastic Assembly of Bacteria in Microwell Arrays Reveals the Importance of Confinement in Community Development

DOE PAGES

Hansen, Ryan H.; Timm, Andrea C.; Timm, Collin M.; ...

2016-05-06

The structure, function and evolving composition of microbial communities is deeply influenced by the physical and chemical architecture of the local microenvironment. The complexity of this parameter space in naturally occurring systems has made a clear understanding of the key drivers of community development elusive. Here, we examine the role of spatial confinement on community development using a microwell platform that allows for assembly and monitoring of unique microbial communities en masse. This platform was designed to contain microwells with varied size features in order to mimic various levels of spatial confinement found in natural systems. Microbial populations assembled inmore » wells with incrementally smaller size features showed increasingly larger variations in inoculum levels. By exploiting this size dependence, large wells were used to assemble homogenous initial populations of Pseudomonas aeruginosa, allowing for reproducible, directed growth trajectories. In contrast, smaller wells were used to assemble a heterogeneous range of initial populations, resulting in a variety of growth and decay trajectories. This allowed for parallel screening of single member communities across different levels of confinement to identify initial conditions in which P. aeruginosa colonies have dramatically higher probabilities of survival. These results demonstrate a unique approach for manipulating the distribution of initial microbial populations assembled into controlled microenvironments to rapidly identify population and environmental parameters conducive or inhibitive to growth. Additionally, multi-member community assembly was characterized to demonstrate the power of this platform for studying the role of member abundance on microbial competition, mutualism and community succession.« less

Large-scale mitochondrial COI gene sequence variability reflects the complex colonization history of the invasive soft-shell clam, Mya arenaria (L.) (Bivalvia)

NASA Astrophysics Data System (ADS)

Lasota, Rafal; Pierscieniak, Karolina; Garcia, Pascale; Simon-Bouhet, Benoit; Wolowicz, Maciej

2016-11-01

The aim of the study was to determine genetic diversity in the soft-shell clam Mya arenaria on a wide geographical scale using mtDNA COI gene sequences. Low levels of genetic diversity was found, which can most likely be explained by a bottleneck effect during Pleistocene glaciations and/or selection. The geographical genetic structuring of the studied populations was also very low. The star-like phylogeny of the haplotypes indicates a relatively recent, rapid population expansion following the glaciation period and repeated expansion following the founder effect(s) after the initial introduction of the soft-shell clam to Europe. North American populations are characterized by the largest number of haplotypes, including rare ones, as expected for native populations. Because of the founder effect connected with initial and repeated expansion events, European populations have significantly lower numbers of haplotypes in comparison with those of North America. We also observed subtle differentiations among populations from the North and Baltic seas. The recently founded soft-shell clam population in the Black Sea exhibited the highest genetic similarity to Baltic populations, which confirmed the hypothesis that M. arenaria was introduced to the Gulf of Odessa from the Baltic Sea. The most enigmatic results were obtained for populations from the White Sea, which were characterized by high genetic affinity with American populations.

Sick leave and disability pension before and after initiation of antirheumatic therapies in clinical practice.

PubMed

Neovius, M; Simard, J F; Klareskog, L; Askling, J

2011-08-01

To investigate sick leave and disability pension in rheumatoid arthritis (RA) in relation to the initiation of biological and non-biological antirheumatic therapies in clinical practice. Patients aged 19-60 years initiating non-biological mono (n=2796) or combination disease-modifying antirheumatic drug (DMARD) therapy (n=973), or biological agents (n=4787) were identified in the Swedish Rheumatology Quality Register between 1999 and 2007. Sick leave and disability pension data (1995-2010) were retrieved from national registers. During the year before the start of mono DMARD, combination DMARD and biological treatment, 10%, 12% and 43% of patients received disability pension benefits, respectively. The corresponding combined annual sick leave and disability pension days were 78 (54+25), 132 (105+27) and 190 (79+111). Irrespective of treatment type, initiators were characterised by a history of increasing sick leave and disability pension. Treatment start was associated with a break in this trajectory: sick leave decreased while disability pension increased, resulting in a net stabilisation of total days. Higher levels of days on sick leave and disability pension at treatment start were observed in patients initiating biologics in 1999 (236 days/year) compared with 2007 (150 days/year; p<0.001), but the trajectory thereafter remained largely similar and contrasted markedly with the level in the general population. Sick leave and disability pension increased rapidly before the initiation of antirheumatic therapy, which was associated with a halt but not a reversal of this development. Work ability is a metric of importance for clinical practice, signalling large remaining needs in the RA population, and the need for intervention earlier in the disease process.

Public Health Adaptation to Climate Change in Large Cities: A Global Baseline.

PubMed

Araos, Malcolm; Austin, Stephanie E; Berrang-Ford, Lea; Ford, James D

2016-01-01

Climate change will have significant impacts on human health, and urban populations are expected to be highly sensitive. The health risks from climate change in cities are compounded by rapid urbanization, high population density, and climate-sensitive built environments. Local governments are positioned to protect populations from climate health risks, but it is unclear whether municipalities are producing climate-adaptive policies. In this article, we develop and apply systematic methods to assess the state of public health adaptation in 401 urban areas globally with more than 1 million people, creating the first global baseline for urban public health adaptation. We find that only 10% of the sampled urban areas report any public health adaptation initiatives. The initiatives identified most frequently address risks posed by extreme weather events and involve direct changes in management or behavior rather than capacity building, research, or long-term investments in infrastructure. Based on our characterization of the current urban health adaptation landscape, we identify several gaps: limited evidence of reporting of institutional adaptation at the municipal level in urban areas in the Global South; lack of information-based adaptation initiatives; limited focus on initiatives addressing infectious disease risks; and absence of monitoring, reporting, and evaluation. © The Author(s) 2015.

Georges Bank: a leaky incubator of Alexandrium fundyense blooms

PubMed Central

McGillicuddy, D.J.; Townsend, D.W.; Keafer, B.A.; Thomas, M.A.; Anderson, D.M.

2012-01-01

A series of oceanographic surveys on Georges Bank document variability of populations of the toxic dinoflagellate Alexandrium fundyense on time scales ranging from synoptic to seasonal to interannual. Blooms of A. fundyense on Georges Bank can reach concentrations on the order of 104 cells l−1, and are generally bank-wide in extent. Georges Bank populations of A. fundyense appear to be quasi-independent of those in the adjacent coastal Gulf of Maine, insofar as they occupy a hydrographic niche that is colder and saltier than their coastal counterparts. In contrast to coastal populations that rely on abundant resting cysts for bloom initiation, very few cysts are present in the sediments on Georges Bank. Bloom dynamics must therefore be largely controlled by the balance between growth and mortality processes, which are at present largely unknown for this population. Based on correlations between cell abundance and nutrient distributions, ammonium appears to be an important source of nitrogen for A. fundyense blooms on Georges Bank. PMID:24976691

Georges Bank: a leaky incubator of Alexandrium fundyense blooms.

PubMed

McGillicuddy, D J; Townsend, D W; Keafer, B A; Thomas, M A; Anderson, D M

2014-05-01

A series of oceanographic surveys on Georges Bank document variability of populations of the toxic dinoflagellate Alexandrium fundyense on time scales ranging from synoptic to seasonal to interannual. Blooms of A. fundyense on Georges Bank can reach concentrations on the order of 10 4 cells l -1 , and are generally bank-wide in extent. Georges Bank populations of A. fundyense appear to be quasi-independent of those in the adjacent coastal Gulf of Maine, insofar as they occupy a hydrographic niche that is colder and saltier than their coastal counterparts. In contrast to coastal populations that rely on abundant resting cysts for bloom initiation, very few cysts are present in the sediments on Georges Bank. Bloom dynamics must therefore be largely controlled by the balance between growth and mortality processes, which are at present largely unknown for this population. Based on correlations between cell abundance and nutrient distributions, ammonium appears to be an important source of nitrogen for A. fundyense blooms on Georges Bank.

Using Large-Eddy Simulation to Explore Microphysical Precursor Conditions for Precipitation Initiation in Marine Stratocumulus

NASA Astrophysics Data System (ADS)

Chandler, H.; Mechem, D. B.; Fridlind, A. M.; Ackerman, A. S.

2016-12-01

Although the classical model of how a population of cloud droplets grows to precipitation-sized drops through the condensation and coalescence processes is well accepted, it does not fully address the history of how nascent precipitation drops come about in warm clouds. Precipitation initiation is influenced by the properties of the cloud drop distribution and in bulk large-eddy simulation (LES) models is parameterized by autoconversion. Double-moment formulations of autoconversion rate generally weight cloud water content qc more than cloud drop concentration Nc (e.g., qc2.47Nc-1.79, Khairoutdinov and Kogan 2000) and precipitation rate scalings derived from field campaigns suggest a dominance of thermodynamic over aerosol factors. However, the mechanisms that drive precipitation initiation in any given cloud are still uncertain. From the perspective of autoconversion, do the regions where precipitation onset occurs experience large liquid water content values (large qc), or are they anomalously clean (small Nc)? Recent laboratory measurements suggest that fluctuations in the supersaturation field may also play a role in precipitation initiation. This study explores the nature of precursor conditions to precipitation onset within marine stratocumulus clouds. We apply an LES model with size-resolving microphysics to a case of marine stratocumulus over the eastern north Atlantic. Backward trajectories originating from regions of precipitation initiation are calculated from the time-evolving LES flow fields to examine the history of fluid parcels that ultimately contain embryonic precipitation.

MaCH-Admix: Genotype Imputation for Admixed Populations

PubMed Central

Liu, Eric Yi; Li, Mingyao; Wang, Wei; Li, Yun

2012-01-01

Imputation in admixed populations is an important problem but challenging due to the complex linkage disequilibrium (LD) pattern. The emergence of large reference panels such as that from the 1,000 Genomes Project enables more accurate imputation in general, and in particular for admixed populations and for uncommon variants. To efficiently benefit from these large reference panels, one key issue to consider in modern genotype imputation framework is the selection of effective reference panels. In this work, we consider a number of methods for effective reference panel construction inside a hidden Markov model and specific to each target individual. These methods fall into two categories: identity-by-state (IBS) based and ancestry-weighted approach. We evaluated the performance on individuals from recently admixed populations. Our target samples include 8,421 African Americans and 3,587 Hispanic Americans from the Women’s Health Initiative, which allow assessment of imputation quality for uncommon variants. Our experiments include both large and small reference panels; large, medium, and small target samples; and in genome regions of varying levels of LD. We also include BEAGLE and IMPUTE2 for comparison. Experiment results with large reference panel suggest that our novel piecewise IBS method yields consistently higher imputation quality than other methods/software. The advantage is particularly noteworthy among uncommon variants where we observe up to 5.1% information gain with the difference being highly significant (Wilcoxon signed rank test P-value < 0.0001). Our work is the first that considers various sensible approaches for imputation in admixed populations and presents a comprehensive comparison. PMID:23074066

Correlates of Sexual Abuse and Smoking among French Adults

ERIC Educational Resources Information Center

King, Gary; Guilbert, Philippe; Ward, D. Gant; Arwidson, Pierre; Noubary, Farzad

2006-01-01

Objective: The goal of this study was to examine the association between sexual abuse (SA) and initiation, cessation, and current cigarette smoking among a large representative adult population in France. Method: A random sample size of 12,256 adults (18-75 years of age) was interviewed by telephone concerning demographic variables, health…

Yeast fermentation affected by homo- and hetero-fermentative Lactobacilli isolated from fuel ethanol distilleries with sugarcane products as substrates

USDA-ARS?s Scientific Manuscript database

The antagonism between by yeast and lactobacilli is largely dependent on the initial population of each organism. While homo-fermentative lactobacillus present higher inhibitory effect upon yeast when in equal cell number, in industrial fuel ethanol conditions where high yeast cell densities prevail...

Effects of heterogeneous wealth distribution on public cooperation with collective risk

NASA Astrophysics Data System (ADS)

Wang, Jing; Fu, Feng; Wang, Long

2010-07-01

The distribution of wealth among individuals in real society can be well described by the Pareto principle or “80-20 rule.” How does such heterogeneity in initial wealth distribution affect the emergence of public cooperation, when individuals, the rich and the poor, engage in a collective-risk enterprise, not to gain a profit but to avoid a potential loss? Here we address this issue by studying a simple but effective model based on threshold public goods games. We analyze the evolutionary dynamics for two distinct scenarios, respectively: one with fair sharers versus defectors and the other with altruists versus defectors. For both scenarios, particularly, we in detail study the dynamics of the population with dichotomic initial wealth—the rich versus the poor. Moreover, we demonstrate the possible steady compositions of the population and provide the conditions for stability of these steady states. We prove that in a population with heterogeneous wealth distribution, richer individuals are more likely to cooperate than poorer ones. Participants with lower initial wealth may choose to cooperate only if all players richer than them are cooperators. The emergence of pubic cooperation largely relies on rich individuals. Furthermore, whenever the wealth gap between the rich and the poor is sufficiently large, cooperation of a few rich individuals can substantially elevate the overall level of social cooperation, which is in line with the well-known Pareto principle. Our work may offer an insight into the emergence of cooperative behavior in real social situations where heterogeneous distribution of wealth among individual is omnipresent.

Behavioral health and health care reform models: patient-centered medical home, health home, and accountable care organization.

PubMed

Bao, Yuhua; Casalino, Lawrence P; Pincus, Harold Alan

2013-01-01

Discussions of health care delivery and payment reforms have largely been silent about how behavioral health could be incorporated into reform initiatives. This paper draws attention to four patient populations defined by the severity of their behavioral health conditions and insurance status. It discusses the potentials and limitations of three prominent models promoted by the Affordable Care Act to serve populations with behavioral health conditions: the Patient-Centered Medical Home, the Health Home initiative within Medicaid, and the Accountable Care Organization. To incorporate behavioral health into health reform, policymakers and practitioners may consider embedding in the reform efforts explicit tools-accountability measures and payment designs-to improve access to and quality of care for patients with behavioral health needs.

Behavioral Health and Health Care Reform Models: Patient-Centered Medical Home, Health Home, and Accountable Care Organization

PubMed Central

Bao, Yuhua; Casalino, Lawrence P.; Pincus, Harold Alan

2012-01-01

Discussions of health care delivery and payment reforms have largely been silent about how behavioral health could be incorporated into reform initiatives. This paper draws attention to four patient populations defined by the severity of their behavioral health conditions and insurance status. It discusses the potentials and limitations of three prominent models promoted by the Affordable Care Act to serve populations with behavioral health conditions: the Patient Centered Medical Home, the Health Home initiative within Medicaid, and the Accountable Care Organization. To incorporate behavioral health into health reform, policymakers and practitioners may consider embedding in the reform efforts explicit tools – accountability measures and payment designs – to improve access to and quality of care for patients with behavioral health needs. PMID:23188486

Genetic Divergence Disclosing a Rapid Prehistorical Dispersion of Native Americans in Central and South America

PubMed Central

He, Yungang; Wang, Wei R.; Li, Ran; Wang, Sijia; Jin, Li

2012-01-01

An accurate estimate of the divergence time between Native Americans is important for understanding the initial entry and early dispersion of human beings in the New World. Current methods for estimating the genetic divergence time of populations could seriously depart from a linear relationship with the true divergence for multiple populations of a different population size and significant population expansion. Here, to address this problem, we propose a novel measure to estimate the genetic divergence time of populations. Computer simulation revealed that the new measure maintained an excellent linear correlation with the population divergence time in complicated multi-population scenarios with population expansion. Utilizing the new measure and microsatellite data of 21 Native American populations, we investigated the genetic divergences of the Native American populations. The results indicated that genetic divergences between North American populations are greater than that between Central and South American populations. None of the divergences, however, were large enough to constitute convincing evidence supporting the two-wave or multi-wave migration model for the initial entry of human beings into America. The genetic affinity of the Native American populations was further explored using Neighbor-Net and the genetic divergences suggested that these populations could be categorized into four genetic groups living in four different ecologic zones. The divergence of the population groups suggests that the early dispersion of human beings in America was a multi-step procedure. Further, the divergences suggest the rapid dispersion of Native Americans in Central and South Americas after a long standstill period in North America. PMID:22970308

The role of colonization in the dynamics of patchy populations of a cyclic vole species.

PubMed

Glorvigen, Petter; Gundersen, Gry; Andreassen, Harry P; Ims, Rolf A

2013-09-01

The crash phase of vole populations with cyclic dynamics regularly leads to vast areas of uninhabited habitats. Yet although the capacity for cyclic voles to re-colonize such empty space is likely to be large and predicted to have become evolved as a distinct life history trait, the processes of colonization and its effect on the spatio-temporal dynamics have been little studied. Here we report from an experiment with root voles (Microtus oeconomus) specifically targeted at quantifying the process of colonization of empty patches from distant source patches and its resultant effect on local vole deme size variation in a patchy landscape. Three experimental factors: habitat quality, predation risk and inter-patch distance were employed among 24 habitat patches in a 100 × 300-m experimental area. The first-born cohort in the spring efficiently colonized almost all empty patches irrespective of the degree of patch isolation and predation risk, but this was dependent on habitat quality. Just after the initial colonization wave the deme sizes in patches of the same quality were underdispersed relative to Poisson variance, indicating regulated (density-dependent) settlement. Towards the end of the breeding season local demographic processes acted to smooth out the initial post-colonization differences among source and colonization patches, and among patches of initially different quality. However, at this time demographic stochasticity had also given rise to a large (overdispersed) variation in deme sizes that may have contributed to an overshadowing of the effect of other factors. The results of this experiment confirmed our expectation that the space-filling capacity of voles is large. The costs associated with transience appeared to be so low, at least at the spatial scale considered in this experiment, that such costs are not likely to substantially constrain habitat selection and colonization in the increase phase of cyclic patchy populations.

A new mechanistic approach for the further development of a population with established size bimodality

USGS Publications Warehouse

Heerman, Lisa; DeAngelis, Donald L.; Borcherding, Jost

2017-01-01

Usually, the origin of a within-cohort bimodal size distribution is assumed to be caused by initial size differences or by one discrete period of accelerated growth for one part of the population. The aim of this study was to determine if more continuous pathways exist allowing shifts from the small to the large fraction within a bimodal age-cohort. Therefore, a Eurasian perch population, which had already developed a bimodal size-distribution and had differential resource use of the two size-cohorts, was examined. Results revealed that formation of a bimodal size-distribution can be a continuous process. Perch from the small size-cohort were able to grow into the large size-cohort by feeding on macroinvertebrates not used by their conspecifics. The diet shifts were accompanied by morphological shape changes. Intra-specific competition seemed to trigger the development towards an increasing number of large individuals. A stage-structured matrix model confirmed these assumptions. The fact that bimodality can be a continuous process is important to consider for the understanding of ecological processes and links within ecosystems.

A new mechanistic approach for the further development of a population with established size bimodality

PubMed Central

DeAngelis, Donald L.; Borcherding, Jost

2017-01-01

Usually, the origin of a within-cohort bimodal size distribution is assumed to be caused by initial size differences or by one discrete period of accelerated growth for one part of the population. The aim of this study was to determine if more continuous pathways exist allowing shifts from the small to the large fraction within a bimodal age-cohort. Therefore, a Eurasian perch population, which had already developed a bimodal size-distribution and had differential resource use of the two size-cohorts, was examined. Results revealed that formation of a bimodal size-distribution can be a continuous process. Perch from the small size-cohort were able to grow into the large size-cohort by feeding on macroinvertebrates not used by their conspecifics. The diet shifts were accompanied by morphological shape changes. Intra-specific competition seemed to trigger the development towards an increasing number of large individuals. A stage-structured matrix model confirmed these assumptions. The fact that bimodality can be a continuous process is important to consider for the understanding of ecological processes and links within ecosystems. PMID:28650963

Heritable victimization and the benefits of agonistic relationships

PubMed Central

Lea, Amanda J.; Blumstein, Daniel T.; Wey, Tina W.; Martin, Julien G. A.

2010-01-01

Here, we present estimates of heritability and selection on network traits in a single population, allowing us to address the evolutionary potential of social behavior and the poorly understood link between sociality and fitness. To evolve, sociality must have some heritable basis, yet the heritability of social relationships is largely unknown. Recent advances in both social network analyses and quantitative genetics allow us to quantify attributes of social relationships and estimate their heritability in free-living populations. Our analyses addressed a variety of measures (in-degree, out-degree, attractiveness, expansiveness, embeddedness, and betweenness), and we hypothesized that traits reflecting relationships controlled by an individual (i.e., those that the individual initiated or were directly involved in) would be more heritable than those based largely on the behavior of conspecifics. Identifying patterns of heritability and selection among related traits may provide insight into which types of relationships are important in animal societies. As expected, we found that variation in indirect measures was largely explained by nongenetic variation. Yet, surprisingly, traits capturing initiated interactions do not possess significant additive genetic variation, whereas measures of received interactions are heritable. Measures describing initiated aggression and position in an agonistic network are under selection (0.3 < |S| < 0.4), although advantageous trait values are not inherited by offspring. It appears that agonistic relationships positively influence fitness and seemingly costly or harmful ties may, in fact, be beneficial. Our study highlights the importance of studying agonistic as well as affiliative relationships to understand fully the connections between sociality and fitness. PMID:21115836

North-South Colonization Associated with Local Adaptation of the Wild Tomato Species Solanum chilense.

PubMed

Böndel, Katharina B; Lainer, Hilde; Nosenko, Tetyana; Mboup, Mamadou; Tellier, Aurélien; Stephan, Wolfgang

2015-11-01

After colonization population sizes may vary across the species range depending on environmental conditions and following colonizations. An interesting question is whether local adaptation occurs more frequently in large ancestral populations or in small derived populations. A higher number of new mutations and a lower effect of genetic drift should favor selection in large populations, whereas small derived populations may require an initial local adaptation event to facilitate the colonization of new habitats. Wild tomatoes are native to a broad range of different habitats characterized by variable abiotic conditions in South America, and represent an ideal system to study this interplay between demography and natural selection. Population genetic analyses and statistical inference of past demography were conducted on pooled-sequencing data from 30 genes (8,080 single nucleotide polymorphisms) from an extensive sampling of 23 Solanum chilense populations over Chile and Peru. We reveal first a north-south colonization associated with relaxed purifying selection in the south as shown by a decrease of genetic variation and an increasing proportion of nonsynonymous polymorphism from north to south, and population substructure with at least four genetic groups. Second, we uncover a dual picture of adaptation consisting of 1) a decreasing proportion of adaptive amino acid substitutions from north to south suggesting that adaptation is favored in large populations, whereas 2) signatures of local adaptation predominantly occur in the smaller populations from the marginal ranges in the south. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Renal Denervation for Treatment of Hypertension: a Second Start and New Challenges.

PubMed

Persu, Alexandre; Kjeldsen, Sverre; Staessen, Jan A; Azizi, Michel

2016-01-01

Following the publication of the randomized controlled but open-label trial Symplicity HTN-2, catheter-based renal sympathetic denervation was proposed as a novel treatment for drug-resistant hypertension. Thousands of procedures were routinely performed in Europe, Australia and Asia, and many observational studies were published. A sudden shift from overoptimistic views to radical scepticism occurred later, when the large US randomized sham-controlled trial Symplicity HTN-3 failed to meet its primary blood pressure lowering efficacy endpoint. Experts are divided on the reasons accounting for the large discrepancy between the results of initial studies and those of Symplicity HTN-3. Indeed, the blood pressure lowering effect associated with renal denervation was overestimated in initial trials due to various patient and physician-related biases, whereas it could have been underestimated in Symplicity HTN-3, which was well designed but not rigorously executed. Still, there is a large consensus on the need to further study catheter-based renal denervation in more controlled conditions, with particular emphasis on identification of predictors of blood pressure response. US and European experts have recently issued very similar recommendations on design of upcoming trials, procedural aspects, drug treatment, patient population and inclusion-exclusion criteria. Application of these new standards may represent a second chance for renal denervation to demonstrate--or not--its efficacy and safety in various patient populations. With its highly standardized treatment regimen, the French trial DENERHTN paved the way for this new approach and may inspire upcoming studies testing novel renal denervation systems in different populations.

Quantum kinetic expansion in the spin-boson model: Matrix formulation and system-bath factorized initial state.

PubMed

Gong, Zhihao; Tang, Zhoufei; Wang, Haobin; Wu, Jianlan

2017-12-28

Within the framework of the hierarchy equation of motion (HEOM), the quantum kinetic expansion (QKE) method of the spin-boson model is reformulated in the matrix representation. The equivalence between the two formulations (HEOM matrices and quantum operators) is numerically verified from the calculation of the time-integrated QKE rates. The matrix formulation of the QKE is extended to the system-bath factorized initial state. Following a one-to-one mapping between HEOM matrices and quantum operators, a quantum kinetic equation is rederived. The rate kernel is modified by an extra term following a systematic expansion over the site-site coupling. This modified QKE is numerically tested for its reliability by calculating the time-integrated rate and non-Markovian population kinetics. For an intermediate-to-strong dissipation strength and a large site-site coupling, the population transfer is found to be significantly different when the initial condition is changed from the local equilibrium to system-bath factorized state.

How are mood and exercise related? Results from the Finnmark study.

PubMed

Sexton, H; Søgaard, A J; Olstad, R

2001-07-01

Recreational exercise and mood have frequently been correlated in population studies. Although it is often assumed that recreational exercise improves mood, this has not been consistently demonstrated in population studies. The relationship between mood and exercise was studied prospectively in a community sample. A series of synchronous panel models was constructed in two samples (2798 paired observations; sample I = 1219, sample II = 1498) to examine this relationship in the entire population, for women and men separately, for those with sedentary occupations, for those performing physical labour, and for those who initially showed a more dysphoric mood. Although mood and exercise were correlated, the only directional relationship that could be demonstrated was that recreational exercise had an inconsistently positive effect upon mood in those with sedentary occupations. There was no such relationship between doing physical work and mood. Analyses of those who initially showed higher levels of dysphoria did not uncover any directional relationship between mood and exercise. None of the other subgroups showed any directional effects between mood and recreational exercise, nor did the population as a whole. The relationship between exercise and mood in this population sample appears to be largely correlational in nature. This result suggests the need to take a cautious view of the role played by exercise in promoting mood in the general population.

Medicare utilization, screening, and costs among participants in the Southeastern Diabetes Initiative: A population-based evaluation.

PubMed

Van Houtven, Courtney H; Greiner, Melissa A; Heidenfelder, Brooke; Spratt, Susan E; Granger, Bradi B; Dunham, Ashley A; Qualls, Laura G; Curtis, Lesley H

2018-04-01

Type 2 diabetes mellitus imposes significant burdens on patients and health care systems. Population-level interventions are being implemented to reach large numbers of patients at risk of or diagnosed with diabetes. We describe a population-based evaluation of the Southeastern Diabetes Initiative (SEDI) from the perspective of a payer, the Centers for Medicare & Medicaid Services (CMS). The purpose of this paper is to describe the population-based evaluation approach of the SEDI intervention from a Medicare utilization and cost perspective. We measured associations between the SEDI intervention and receipt of diabetes screening (i.e., HbA1c test, eye exam, lipid profile), health care resource use, and costs among intervention enrollees, compared with a control cohort of Medicare beneficiaries in geographically adjacent counties. The intervention cohort had slightly lower 1-year screening in 2 of 3 domains (4% for HbA1c; 9% for lipid profiles) in the post-intervention period, compared with the control cohort. The SEDI intervention cohort did not have different Medicare utilization or total Medicare costs in the post-intervention period from surrounding control counties. Our analytic approach may be useful to others evaluating CMS demonstration projects in which population-level health is targeted for improvement in a well-defined clinical population. Published by Elsevier Ltd.

Clinical research in small genomically stratified patient populations.

PubMed

Martin-Liberal, J; Rodon, J

2017-07-01

The paradigm of early drug development in cancer is shifting from 'histology-oriented' to 'molecularly oriented' clinical trials. This change can be attributed to the vast amount of tumour biology knowledge generated by large international research initiatives such as The Cancer Genome Atlas (TCGA) and the use of next generation sequencing (NGS) techniques developed in recent years. However, targeting infrequent molecular alterations entails a series of special challenges. The optimal molecular profiling method, the lack of standardised biological thresholds, inter- and intra-tumor heterogeneity, availability of enough tumour material, correct clinical trials design, attrition rate, logistics or costs are only some of the issues that need to be taken into consideration in clinical research in small genomically stratified patient populations. This article examines the most relevant challenges inherent to clinical research in these populations. Moreover, perspectives from the Academia point of view are reviewed as well as initiatives to be taken in forthcoming years. Copyright © 2017 Elsevier Ltd. All rights reserved.

University of Puget Sound American Association of Colleges/Mellon Foundation Transfer Student Project: 1985-86 Report.

ERIC Educational Resources Information Center

Copeland, Scott A.

The University of Puget Sound's (UPS's) transfer student project was designed to aid black community college transfer students in pursuing a baccalaureate degree in business administration. Initially, Tacoma Community College (TCC) was targeted as the project partner because of its close proximity to UPS, its large minority population, and the…

Science Initial Teacher Education and Superdiversity: Educating Science Teachers for a Multi-Religious and Globalised Science Classroom

ERIC Educational Resources Information Center

De Carvalho, Roussel

2016-01-01

Steven Vertovec (2006, 2007) has recently offered a re-interpretation of population diversity in large urban centres due to a considerable increase in immigration patterns in the UK. This complex scenario called superdiversity has been conceptualised to help illuminate significant interactions of variables such as religion, language, gender, age,…

Spatial synchrony propagates through a forest food web via consumer-resource interactions

Treesearch

Kyle J. ​Haynes; Andrew M. Liebhold; Todd M. Fearer; Guiming Wang; Gary W. Norman; Derek M. Johnson

2009-01-01

In many study systems, populations fluctuate synchronously across large regions. Several mechanisms have been advanced to explain this, but their importance in nature is often uncertain. Theoretical studies suggest that spatial synchrony initiated in one species through Moran effects may propagate among trophically linked species, but evidence for this in nature is...

Evolution of the stellar mass function in multiple-population globular clusters

NASA Astrophysics Data System (ADS)

Vesperini, Enrico; Hong, Jongsuk; Webb, Jeremy J.; D'Antona, Franca; D'Ercole, Annibale

2018-05-01

We present the results of a survey of N-body simulations aimed at studying the effects of the long-term dynamical evolution on the stellar mass function (MF) of multiple stellar populations in globular clusters. Our simulations show that if first-(1G) and second-generation (2G) stars have the same initial MF (IMF), the global MFs of the two populations are affected similarly by dynamical evolution and no significant differences between the 1G and 2G MFs arise during the cluster's evolution. If the two populations have different IMFs, dynamical effects do not completely erase memory of the initial differences. Should observations find differences between the global 1G and 2G MFs, these would reveal the fingerprints of differences in their IMFs. Irrespective of whether the 1G and 2G populations have the same global IMF or not, dynamical effects can produce differences between the local (measured at various distances from the cluster centre) 1G and 2G MFs; these differences are a manifestation of the process of mass segregation in populations with different initial structural properties. In dynamically old and spatially mixed clusters, however, differences between the local 1G and 2G MFs can reveal differences between the 1G and 2G global MFs. In general, for clusters with any dynamical age, large differences between the local 1G and 2G MFs are more likely to be associated with differences in the global MF. Our study also reveals a dependence of the spatial mixing rate on the stellar mass, another dynamical consequence of the multiscale nature of multiple-population clusters.

Field cage studies and progressive evaluation of genetically-engineered mosquitoes.

PubMed

Facchinelli, Luca; Valerio, Laura; Ramsey, Janine M; Gould, Fred; Walsh, Rachael K; Bond, Guillermo; Robert, Michael A; Lloyd, Alun L; James, Anthony A; Alphey, Luke; Scott, Thomas W

2013-01-01

A genetically-engineered strain of the dengue mosquito vector Aedes aegypti, designated OX3604C, was evaluated in large outdoor cage trials for its potential to improve dengue prevention efforts by inducing population suppression. OX3604C is engineered with a repressible genetic construct that causes a female-specific flightless phenotype. Wild-type females that mate with homozygous OX3604C males will not produce reproductive female offspring. Weekly introductions of OX3604C males eliminated all three targeted Ae. aegypti populations after 10-20 weeks in a previous laboratory cage experiment. As part of the phased, progressive evaluation of this technology, we carried out an assessment in large outdoor field enclosures in dengue endemic southern Mexico. OX3604C males were introduced weekly into field cages containing stable target populations, initially at 10:1 ratios. Statistically significant target population decreases were detected in 4 of 5 treatment cages after 17 weeks, but none of the treatment populations were eliminated. Mating competitiveness experiments, carried out to explore the discrepancy between lab and field cage results revealed a maximum mating disadvantage of up 59.1% for OX3604C males, which accounted for a significant part of the 97% fitness cost predicted by a mathematical model to be necessary to produce the field cage results. Our results indicate that OX3604C may not be effective in large-scale releases. A strain with the same transgene that is not encumbered by a large mating disadvantage, however, could have improved prospects for dengue prevention. Insights from large outdoor cage experiments may provide an important part of the progressive, stepwise evaluation of genetically-engineered mosquitoes.

Field Cage Studies and Progressive Evaluation of Genetically-Engineered Mosquitoes

PubMed Central

Facchinelli, Luca; Valerio, Laura; Ramsey, Janine M.; Gould, Fred; Walsh, Rachael K.; Bond, Guillermo; Robert, Michael A.; Lloyd, Alun L.; James, Anthony A.; Alphey, Luke; Scott, Thomas W.

2013-01-01

Background A genetically-engineered strain of the dengue mosquito vector Aedes aegypti, designated OX3604C, was evaluated in large outdoor cage trials for its potential to improve dengue prevention efforts by inducing population suppression. OX3604C is engineered with a repressible genetic construct that causes a female-specific flightless phenotype. Wild-type females that mate with homozygous OX3604C males will not produce reproductive female offspring. Weekly introductions of OX3604C males eliminated all three targeted Ae. aegypti populations after 10–20 weeks in a previous laboratory cage experiment. As part of the phased, progressive evaluation of this technology, we carried out an assessment in large outdoor field enclosures in dengue endemic southern Mexico. Methodology/Principal Findings OX3604C males were introduced weekly into field cages containing stable target populations, initially at 10∶1 ratios. Statistically significant target population decreases were detected in 4 of 5 treatment cages after 17 weeks, but none of the treatment populations were eliminated. Mating competitiveness experiments, carried out to explore the discrepancy between lab and field cage results revealed a maximum mating disadvantage of up 59.1% for OX3604C males, which accounted for a significant part of the 97% fitness cost predicted by a mathematical model to be necessary to produce the field cage results. Conclusions/Significance Our results indicate that OX3604C may not be effective in large-scale releases. A strain with the same transgene that is not encumbered by a large mating disadvantage, however, could have improved prospects for dengue prevention. Insights from large outdoor cage experiments may provide an important part of the progressive, stepwise evaluation of genetically-engineered mosquitoes. PMID:23350003

Barriers to and acceptability of provider-initiated HIV testing and counselling and adopting HIV-prevention behaviours in rural Uganda: a qualitative study.

PubMed

Kiene, Susan M; Sileo, Katelyn; Wanyenze, Rhoda K; Lule, Haruna; Bateganya, Moses H; Jasperse, Joseph; Nantaba, Harriet; Jayaratne, Kia

2015-02-01

In Uganda, a nationwide scale-up of provider-initiated HIV testing and counselling presents an opportunity to deliver HIV-prevention services to large numbers of people. In a rural Ugandan hospital, focus group discussions and key informant interviews were conducted with outpatients receiving provider-initiated HIV testing and counselling and staff to explore the HIV-prevention information, motivation and behavioural skills strengths and weaknesses, and community-level and structural barriers to provider-initiated HIV testing and counselling acceptability and HIV prevention among this population. Strengths and weakness occurred at all levels, and results suggest brief client-centred interventions during provider-initiated HIV testing and counselling may be an effective approach to increase prevention behaviours in outpatient settings. © The Author(s) 2013.

CONSTRAINING THE GRB-MAGNETAR MODEL BY MEANS OF THE GALACTIC PULSAR POPULATION

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

Rea, N.; Gullón, M.; Pons, J. A.

2015-11-10

A large fraction of Gamma-ray bursts (GRBs) displays an X-ray plateau phase within <10{sup 5} s from the prompt emission, proposed to be powered by the spin-down energy of a rapidly spinning newly born magnetar. In this work we use the properties of the Galactic neutron star population to constrain the GRB-magnetar scenario. We re-analyze the X-ray plateaus of all Swift GRBs with known redshift, between 2005 January and 2014 August. From the derived initial magnetic field distribution for the possible magnetars left behind by the GRBs, we study the evolution and properties of a simulated GRB-magnetar population using numericalmore » simulations of magnetic field evolution, coupled with Monte Carlo simulations of Pulsar Population Synthesis in our Galaxy. We find that if the GRB X-ray plateaus are powered by the rotational energy of a newly formed magnetar, the current observational properties of the Galactic magnetar population are not compatible with being formed within the GRB scenario (regardless of the GRB type or rate at z = 0). Direct consequences would be that we should allow the existence of magnetars and “super-magnetars” having different progenitors, and that Type Ib/c SNe related to Long GRBs form systematically neutron stars with higher initial magnetic fields. We put an upper limit of ≤16 “super-magnetars” formed by a GRB in our Galaxy in the past Myr (at 99% c.l.). This limit is somewhat smaller than what is roughly expected from Long GRB rates, although the very large uncertainties do not allow us to draw strong conclusion in this respect.« less

CD133+ tumor initiating cells in a syngenic murine model of pancreatic cancer respond to Minnelide.

PubMed

Banerjee, Sulagna; Nomura, Alice; Sangwan, Veena; Chugh, Rohit; Dudeja, Vikas; Vickers, Selwyn M; Saluja, Ashok

2014-05-01

Pancreatic adenocarcinoma is the fourth leading cause for cancer-related mortality with a survival rate of less than 5%. Late diagnosis and lack of effective chemotherapeutic regimen contribute to these grim survival statistics. Relapse of any tumor is largely attributed to the presence of tumor-initiating cells (TIC) or cancer stem cells (CSC). These cells are considered as hurdles to cancer therapy as no known chemotherapeutic compound is reported to target them. Thus, there is an urgent need to develop a TIC-targeted therapy for pancreatic cancer. We isolated CD133(+) cells from a spontaneous pancreatic ductal adenocarcinoma mouse model and studied both surface expression, molecular markers of pancreatic TICs. We also studied tumor initiation properties by implanting low numbers of CD133(+) cells in immune competent mice. Effect of Minnelide, a drug currently under phase I clinical trial, was studied on the tumors derived from the CD133(+) cells. Our study showed for the first time that CD133(+) population demonstrated all the molecular markers for pancreatic TIC. These cells initiated tumors in immunocompetent mouse models and showed increased expression of prosurvival and proinvasive proteins compared to the CD133(-) non-TIC population. Our study further showed that Minnelide was very efficient in downregulating both CD133(-) and CD133(+) population in the tumors, resulting in a 60% decrease in tumor volume compared with the untreated ones. As Minnelide is currently under phase I clinical trial, its evaluation in reducing tumor burden by decreasing TIC as well as non-TIC population suggests its potential as an effective therapy. ©2014 AACR.

Assessment of health impacts of decreased smoking prevalence in Copenhagen: Application of the DYNAMO-HIA model.

PubMed

Holm, Astrid Ledgaard; Brønnum-Hansen, Henrik; Robinson, Kirstine Magtengaard; Diderichsen, Finn

2014-07-01

Tobacco smoking is among the leading risk factors for chronic disease and early death in developed countries, including Denmark, where smoking causes 14% of the disease burden. In Denmark, many public health interventions, including smoking prevention, are undertaken by the municipalities, but models to estimate potential health effects of local interventions are lacking. The aim of the current study was to model the effects of decreased smoking prevalence in Copenhagen, Denmark. The DYNAMO-HIA model was applied to the population of Copenhagen, by using health survey data and data from Danish population registers. We modelled the effects of four intervention scenarios aimed at different target groups, compared to a reference scenario. The potential effects of each scenario were modelled until 2040. A combined scenario affecting both initiation rates among youth, and cessation and re-initiation rates among adults, which reduced the smoking prevalence to 4% by 2025, would have large beneficial effects on incidence and prevalence of smoking-related diseases and mortality. Health benefits could also be obtained through interventions targeting only cessation or re-initiation rates, whereas an intervention targeting only initiation among youth had marginal effects on morbidity and mortality within the modelled time frame. By modifying the DYNAMO-HIA model, we were able to estimate the potential health effects of four interventions to reduce smoking prevalence in the population of Copenhagen. The effect of the interventions on future public health depended on population subgroup(s) targeted, duration of implementation and intervention reach. © 2014 the Nordic Societies of Public Health.

Population dynamics of aberrant chromosome 1 in mice.

PubMed

Sabantsev, I; Spitsin, O; Agulnik, S; Ruvinsky, A

1993-05-01

Natural populations of two semispecies of house mouse, Mus musculus domesticus and M.m. musculus, were found to be polymorphic for an aberrant chromosome 1 bearing a large inserted block of homogeneously staining heterochromatin. Strong meiotic drive for the aberrant chromosome from M.m. musculus was previously observed in heterozygous female mice. There are at least three meiotic drive levels determined by different allelic variants of distorter. Homozygotes had low viability and females showed low fertility. Both homo- and heterozygous males had normal fertility and their segregation patterns did not deviate from normal. Computer simulations were performed of the dynamics of aberrant chromosome 1 in demes and populations. The data demonstrate that a spontaneous mutation (inversion) of an aberrant chromosome 1, once arisen, has a high probability of spreading in a population at high coefficients of meiotic drive and migration. In the long-term, the population attains a stationary state which is determined by the drive level and migration intensity. The state of stable genotypic equilibrium is independent of deme and population size, as well as of the initial concentration of the aberrant chromosome. As populations initially polymorphic for the distorters approach the stationary state, the stronger distorter is eliminated. The frequencies of the aberrant chromosome determined by computer analysis agree well with those obtained for the studied Asian M.m. musculus populations. The evolutionary pathways for the origin and fixation of the aberrant chromosome in natural populations are considered.

Polymorphisms at the innate immune receptor TLR2 are associated with Borrelia infection in a wild rodent population

PubMed Central

Tschirren, Barbara; Andersson, Martin; Scherman, Kristin; Westerdahl, Helena; Mittl, Peer R. E.; Råberg, Lars

2013-01-01

The discovery of the key role of Toll-like receptors (TLRs) in initiating innate immune responses and modulating adaptive immunity has revolutionized our understanding of vertebrate defence against pathogens. Yet, despite their central role in pathogen recognition and defence initiation, there is little information on how variation in TLRs influences disease susceptibility in natural populations. Here, we assessed the extent of naturally occurring polymorphisms at TLR2 in wild bank voles (Myodes glareolus) and tested for associations between TLR2 variants and infection with Borrelia afzelii, a common tick-transmitted pathogen in rodents and one of the causative agents of human Lyme disease. Bank voles in our population had 15 different TLR2 haplotypes (10 different haplotypes at the amino acid level), which grouped in three well-separated clusters. In a large-scale capture–mark–recapture study, we show that voles carrying TLR2 haplotypes of one particular cluster (TLR2c2) were almost three times less likely to be Borrelia infected than animals carrying other haplotypes. Moreover, neutrality tests suggested that TLR2 has been under positive selection. This is, to our knowledge, the first demonstration of an association between TLR polymorphism and parasitism in wildlife, and a striking example that genetic variation at innate immune receptors can have a large impact on host resistance. PMID:23554395

Polymorphisms at the innate immune receptor TLR2 are associated with Borrelia infection in a wild rodent population.

PubMed

Tschirren, Barbara; Andersson, Martin; Scherman, Kristin; Westerdahl, Helena; Mittl, Peer R E; Råberg, Lars

2013-05-22

The discovery of the key role of Toll-like receptors (TLRs) in initiating innate immune responses and modulating adaptive immunity has revolutionized our understanding of vertebrate defence against pathogens. Yet, despite their central role in pathogen recognition and defence initiation, there is little information on how variation in TLRs influences disease susceptibility in natural populations. Here, we assessed the extent of naturally occurring polymorphisms at TLR2 in wild bank voles (Myodes glareolus) and tested for associations between TLR2 variants and infection with Borrelia afzelii, a common tick-transmitted pathogen in rodents and one of the causative agents of human Lyme disease. Bank voles in our population had 15 different TLR2 haplotypes (10 different haplotypes at the amino acid level), which grouped in three well-separated clusters. In a large-scale capture-mark-recapture study, we show that voles carrying TLR2 haplotypes of one particular cluster (TLR2c2) were almost three times less likely to be Borrelia infected than animals carrying other haplotypes. Moreover, neutrality tests suggested that TLR2 has been under positive selection. This is, to our knowledge, the first demonstration of an association between TLR polymorphism and parasitism in wildlife, and a striking example that genetic variation at innate immune receptors can have a large impact on host resistance.

Revisiting convergence: A research note.

PubMed

Clark, Rob

2015-09-01

A number of recent studies show that income inequality is declining between countries. In this research note, I question the significance of this trend by examining the role of initial conditions in producing convergence. An important (but neglected) property of inequality dynamics is the tendency for extreme distributions to become more moderate. When income disparities are large, the subsequent trend is biased toward convergence. Conversely, when initial conditions approach parity, divergence becomes the more likely long-term outcome. I apply this principle to trends in GDP PC across 127 countries during the 1980-2010 period. Using counterfactual analysis, I manipulate the initial level of inequality in GDP PC while holding constant each country's observed growth rate during the sample period. I find that the growth dynamics of GDP PC produce either convergence or divergence based simply on the initial distribution of income. The point of transition occurs at a moderate level of inequality, whether using population weights (Gini=.365) or not (Gini=.377). I conclude that the recent convergence observed in GDP PC is primarily a function of large income gaps between countries and would not have materialized at more moderate levels of initial inequality. By contrast, an examination of the pre-1950 period reveals divergent growth patterns that are not sensitive to initial conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

Population-level interventions in government jurisdictions for dietary sodium reduction.

PubMed

McLaren, Lindsay; Sumar, Nureen; Barberio, Amanda M; Trieu, Kathy; Lorenzetti, Diane L; Tarasuk, Valerie; Webster, Jacqui; Campbell, Norman Rc

2016-09-16

Excess dietary sodium consumption is a risk factor for high blood pressure, stroke and cardiovascular disease. Currently, dietary sodium consumption in almost every country is too high. Excess sodium intake is associated with high blood pressure, which is common and costly and accounts for significant burden of disease. A large number of jurisdictions worldwide have implemented population-level dietary sodium reduction initiatives. No systematic review has examined the impact of these initiatives. • To assess the impact of population-level interventions for dietary sodium reduction in government jurisdictions worldwide.• To assess the differential impact of those initiatives by social and economic indicators. We searched the following electronic databases from their start date to 5 January 2015: the Cochrane Central Register of Controlled Trials (CENTRAL); Cochrane Public Health Group Specialised Register; MEDLINE; MEDLINE In Process & Other Non-Indexed Citations; EMBASE; Effective Public Health Practice Project Database; Web of Science; Trials Register of Promoting Health Interventions (TRoPHI) databases; and Latin American Caribbean Health Sciences Literature (LILACS). We also searched grey literature, other national sources and references of included studies.This review was conducted in parallel with a comprehensive review of national sodium reduction efforts under way worldwide (Trieu 2015), through which we gained additional information directly from country contacts.We imposed no restrictions on language or publication status. We included population-level initiatives (i.e. interventions that target whole populations, in this case, government jurisdictions, worldwide) for dietary sodium reduction, with at least one pre-intervention data point and at least one post-intervention data point of comparable jurisdiction. We included populations of all ages and the following types of study designs: cluster-randomised, controlled pre-post, interrupted time series and uncontrolled pre-post. We contacted study authors at different points in the review to ask for missing information. Two review authors extracted data, and two review authors assessed risk of bias for each included initiative.We analysed the impact of initiatives by using estimates of sodium consumption from dietary surveys or urine samples. All estimates were converted to a common metric: salt intake in grams per day. We analysed impact by computing the mean change in salt intake (grams per day) from pre-intervention to post-intervention. We reviewed a total of 881 full-text documents. From these, we identified 15 national initiatives, including more than 260,000 people, that met the inclusion criteria. None of the initiatives were provided in lower-middle-income or low-income countries. All initiatives except one used an uncontrolled pre-post study design.Because of high levels of study heterogeneity (I 2 > 90%), we focused on individual initiatives rather than on pooled results.Ten initiatives provided sufficient data for quantitative analysis of impact (64,798 participants). As required by the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) method, we graded the evidence as very low due to the risk of bias of the included studies, as well as variation in the direction and size of effect across the studies. Five of these showed mean decreases in average daily salt intake per person from pre-intervention to post-intervention, ranging from 1.15 grams/day less (Finland) to 0.35 grams/day less (Ireland). Two initiatives showed mean increase in salt intake from pre-intervention to post-intervention: Canada (1.66) and Switzerland (0.80 grams/day more per person. The remaining initiatives did not show a statistically significant mean change.Seven of the 10 initiatives were multi-component and incorporated intervention activities of a structural nature (e.g. food product reformulation, food procurement policy in specific settings). Of those seven initiatives, four showed a statistically significant mean decrease in salt intake from pre-intervention to post-intervention, ranging from Finland to Ireland (see above), and one showed a statistically significant mean increase in salt intake from pre-intervention to post-intervention (Switzerland; see above).Nine initiatives permitted quantitative analysis of differential impact by sex (men and women separately). For women, three initiatives (China, Finland, France) showed a statistically significant mean decrease, four (Austria, Netherlands, Switzerland, United Kingdom) showed no significant change and two (Canada, United States) showed a statistically significant mean increase in salt intake from pre-intervention to post-intervention. For men, five initiatives (Austria, China, Finland, France, United Kingdom) showed a statistically significant mean decrease, three (Netherlands, Switzerland, United States) showed no significant change and one (Canada) showed a statistically significant mean increase in salt intake from pre-intervention to post-intervention.Information was insufficient to indicate whether a differential change in mean salt intake occurred from pre-intervention to post-intervention by other axes of equity included in the PROGRESS framework (e.g. education, place of residence).We identified no adverse effects of these initiatives.The number of initiatives was insufficient to permit other subgroup analyses, including stratification by intervention type, economic status of country and duration (or start year) of the initiative.Many studies had methodological strengths, including large, nationally representative samples of the population and rigorous measurement of dietary sodium intake. However, all studies were scored as having high risk of bias, reflecting the observational nature of the research and the use of an uncontrolled study design. The quality of evidence for the main outcome was low. We could perform a sensitivity analysis only for impact. Population-level interventions in government jurisdictions for dietary sodium reduction have the potential to result in population-wide reductions in salt intake from pre-intervention to post-intervention, particularly if they are multi-component (more than one intervention activity) and incorporate intervention activities of a structural nature (e.g. food product reformulation), and particularly amongst men. Heterogeneity across studies was significant, reflecting different contexts (population and setting) and initiative characteristics. Implementation of future initiatives should embed more effective means of evaluation to help us better understand the variation in the effects.

Substance Use among Male Sex Workers in Vietnam: Prevalence, Onset, and Interactions with Sexual Risk

PubMed Central

Yu, Gary; Clatts, Michael C.; Goldsamt, Lloyd A.; Giang, Le Minh

2014-01-01

Background HIV research in Vietnam has focused primarily on its large heroin injector population. Data on men who have sex with men [MSM], particularly the large and growing population of men who exchange sex for money or other material rewards, male sex workers [MSWs], is very limited. Methods Data derive from a cross-sectional study of MSW, age 16-35, recruited using community sampling methods in three cities in 2010-2011, including Hanoi, Ho Chi Minh City [HCMC], and Nha Trang City (n=710). Assessments included demographic characteristics, substance use, sexual risk, and use of health services. A series of “event” questions were used to assess the influence of alcohol and drugs on sexual risk. Results Both tobacco and alcohol are initiated at a young age and most participants currently use both substances overall across all three cities. While alcohol and tobacco use precede the initiation of sex work, stimulant and opiate use are initiated following the initiation of sex work. There was substantial overlap between substance use and sexual risk, and this overlap was strongest in sexual events involving male and female elective partners rather than sex work clients. Conclusion Although rates of HIV infection in this group are low, this may be an artifact of the young age of the sample. High rates of drug use, including alcohol, tobacco and illicit drugs, coupled with high rates of ulcerative STIs such as HPV, suggest the potential for rapid amplification of STI/HIV risk among MSW and their complex sex partnering networks. PMID:25488636

Population growth, fecundity, and survivorship in recovering populations of bighorn sheep

USGS Publications Warehouse

Singer, F.J.; Williams, E.; Miller, M.W.; Zeigenfuss, L.C.

2000-01-01

The single greatest obstacle to the restoration of large, healthy, populations of bighorn sheep (Ovis canadensis) in the western United States is epizootic outbreaks of bronchopneumonia that may kill 20–100% of the animals in populations. Although the species is capable of rapid initial growth rates following restoration into new habitat (λ = 1.23–1.30 have been observed), these rates of increase are typical only a few years following the release of a population, and then most populations either decline to extirpation or remnant status (<30 animals) or remain at <100 individuals. We studied the fecundity and survivorship of three increasing, and three declining and suspected diseased, populations of bighorn sheep (the latter were subjected to outbreaks of bronchopneumonia) located in or near several large national parks in the western United States from 1991 to 1996. Titers verified both population categories were exposed to the bacteria Pasteurella haemolytica serotypes 3; 4; and 3, 4, 10; Moraxella sp., and parainfluenza-3 and bluetongue (BT) viruses. Pregnancy rates of adult ewes were not different in increasing or decreasing populations (pooled rate = 0.93; p = 0.57), but pregnancy rates of yearlings were lower (0.00 for decreasing vs. 0.33 for increasing populations), initial production of lambs and annual recruitment of lambs was lower (0.14, decreasing vs. 0.66, p < 0.05). Adult survival was lower during the first year of an epizootic, 0.62, in one population, but recovered to 0.85 by the second and subsequent years. Survival of adult rams was variable in diseased populations; in two populations rams appeared to be disproportionately impacted, but in a third population rams survived better during the epizootic. In all the increasing park (unhunted) populations, adult ram survival (0.94 ± 0.01) was higher than adult ewe survival (0.89 ± 0.02) (p = 0.10), in contrast to published information from hunted populations where ram survival was lower. Removal of about 20% of one population for restorations severely impacted one declining population. Removals of 12–20% appeared to be excessive and were not readily compensated for in the Canyonlands National Park desert bighorn population. Disease was a significant limiting factor to restoration of bighorn sheep in the study areas; six of 11 total recovering populations we monitored closely were negatively influenced by apparent disease at some time during our observations.

Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants. Report 1. Baseline Studies. Volume VIII. Summary of Baseline Studies and Data.

DTIC Science & Technology

1982-05-01

in May 1976, and, by July 1976, all sampling techniques were employed. In addition to routine displays of data analysis such as frequency tables and...amphibian and reptile communities in large aquatic habitats in Florida, comparison with similar herpetofaunal assemblages or populations is not possible... field environment was initiated at Lake Conway near Orlando, Fla., to study the effectiveness of the fish as a biological macrophyte control agent. A

Heterogeneous network epidemics: real-time growth, variance and extinction of infection.

PubMed

Ball, Frank; House, Thomas

2017-09-01

Recent years have seen a large amount of interest in epidemics on networks as a way of representing the complex structure of contacts capable of spreading infections through the modern human population. The configuration model is a popular choice in theoretical studies since it combines the ability to specify the distribution of the number of contacts (degree) with analytical tractability. Here we consider the early real-time behaviour of the Markovian SIR epidemic model on a configuration model network using a multitype branching process. We find closed-form analytic expressions for the mean and variance of the number of infectious individuals as a function of time and the degree of the initially infected individual(s), and write down a system of differential equations for the probability of extinction by time t that are numerically fast compared to Monte Carlo simulation. We show that these quantities are all sensitive to the degree distribution-in particular we confirm that the mean prevalence of infection depends on the first two moments of the degree distribution and the variance in prevalence depends on the first three moments of the degree distribution. In contrast to most existing analytic approaches, the accuracy of these results does not depend on having a large number of infectious individuals, meaning that in the large population limit they would be asymptotically exact even for one initial infectious individual.

News media coverage of smoking and health is associated with changes in population rates of smoking cessation but not initiation

PubMed Central

Pierce, J.; Gilpin, E.

2001-01-01

OBJECTIVE—To determine whether changes in news media coverage of smoking and health issues are associated with changes in smoking behaviour in the USA.
DESIGN AND MAIN OUTCOME MEASURES—Issue importance in the US news media is assessed by the number of articles published annually in major magazines indexed in The Reader's Guide to Periodical Literature. Annual incidence rates for cessation and initiation in the USA were computed from the large, representative National Health Interview Surveys (1965-1992). Patterns in cessation incidence were considered for ages 20-34 years and 35-50 years. Initiation incidence was examined for adolescents (14-17 years) and young adults (18-21 years) of both sexes.
RESULTS—From 1950 to the early 1980s, the annual incidence of cessation in the USA mirrored the pattern of news media coverage of smoking and health, particularly for middle aged smokers. Cessation rates in younger adults increased considerably when secondhand smoke concerns started to increase in the US population. Incidence of initiation in young adults did not start to decline until the beginning of the public health campaign against smoking in the 1960s. Among adolescents, incidence rates did not start to decline until the 1970s, after the broadcast ban on cigarette advertising.
CONCLUSIONS—The level of coverage of smoking and health in the news media may play an important role in determining the rate of population smoking cessation, but not initiation. In countries where cessation has lagged, advocates should work to increase the newsworthiness of smoking and health issues.


Keywords: initiation; cessation; health; mass media PMID:11387535

Florida Charter Schools: Hot and Humid with Passing Storms. Education Sector Reports: Charter School Series

ERIC Educational Resources Information Center

Hassel, Bryan C.; Terrell, Michelle Godard; Kowal, Julie

2006-01-01

Among many publicly-funded school choice initiatives that have earned Florida the label "school choice central", none has reached as many children and families as charter schools. Charter schools have flourished in Florida largely because of the state's rapid population growth: many of the districts that are experiencing more than a 10…

Association between Anger Rumination and Autism Symptom Severity, Depression Symptoms, Aggression, and General Dysregulation in Adolescents with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Patel, Shivani; Day, Taylor N.; Jones, Neil; Mazefsky, Carla A.

2017-01-01

Rumination has a large direct effect on psychopathology but has received relatively little attention in autism spectrum disorder despite the propensity to perseverate in this population. This study provided initial evidence that adolescents with autism spectrum disorder self-report more anger-focused rumination than typically developing controls,…

Developing a monitoring program for bird populations in the Chiricahua Mountains, Arizona, using citizen observers: Initial stages

Treesearch

Joseph L Ganey; Jose M. Iniguez; Jamie S. Sanderlin; William M. Block

2017-01-01

The Madrean Sky Island region is an ecologically important area harboring exceptional biodiversity, including a unique avifauna that supports a thriving ecotourism industry in southeastern Arizona. This area has been impacted by several large wildfires in recent decades. These wildfires have altered vegetation composition and structure in forests and woodlands, and the...

Ecology of West Nile Fever across four European countries: Review of weather profiles, vector population dynamics and vector control response

USDA-ARS?s Scientific Manuscript database

West Nile virus (WNV) represents a serious burden to human and animal health because of its capacity to cause large unforeseen epidemics. Until 2004, only lineage 1 and 3 WNV strains had been found in Europe. Lineage 2 strains were initially isolated in 2004 (Hungary), again in 2008 (Austria), and f...

CO2 Urban Synthesis and Analysis ("CO2-USA") Network

NASA Astrophysics Data System (ADS)

Lin, J. C.; Hutyra, L.; Loughner, C.; Stein, A. F.; Lusk, K.; Mitchell, L.; Gately, C.; Wofsy, S. C.

2017-12-01

Emissions of carbon associated with cities comprise a large component of the anthropogenic source. A number of cities have announced plans to reduce greenhouse gas emissions, but the scientific knowledge to quantitatively track emissions and assess the efficacy of mitigation is lacking. As the global population increasingly resides in urban regions, scientific knowledge about how much, where, and why a particular city emits carbon becomes increasingly important. To address this gap, researchers have initiated studies of carbon emissions and cycling in several U.S. cities, making it timely to develop a collaborative network to exchange information on community standards and common measurements, facilitate data sharing, and create analysis frameworks and cross-city syntheses to catalyze a new generation of researchers and enable new collaborations tackling important objectives that are difficult to address in isolation. We describe initial results from an incipient network focusing initially on cities in the U.S. with low barriers of entry that entrains a cross-section of U.S. urban centers with varying characteristics: size, population density, vegetation, urban form, infrastructure, development rates, climate, and meteorological patterns. Results will be reported that emerge from an initial workshop covering data harmonization & integration, inventory comparison, stakeholder outreach, network design, inverse modeling, and collaboration.

Emergence of social cooperation in threshold public goods games with collective risk

NASA Astrophysics Data System (ADS)

Wang, Jing; Fu, Feng; Wu, Te; Wang, Long

2009-07-01

In real situations, people are often faced with the option of voluntary contribution to achieve a collective goal, for example, building a dam or a fence, in order to avoid an unfavorable loss. Those who do not donate, however, can free ride on others’ sacrifices. As a result, cooperation is difficult to maintain, leading to an enduring collective-risk social dilemma. To address this issue, here we propose a simple yet effective theoretical model of threshold public goods game with collective risk and focus on the effect of risk on the emergence of social cooperation. To do this, we consider the population dynamics represented by replicator equation for two simplifying scenarios, respectively: one with fair sharers, who contribute the minimum average amount versus defectors and the other with altruists contributing more than average versus defectors. For both cases, we find that the dilemma is relieved in high-risk situations where cooperation is likely to persist and dominate defection in the population. Large initial endowment to individuals also encourages the risk-averse action, which means that, as compared to poor players (with small initial endowment), wealthy individuals (with large initial endowment) are more likely to cooperate in order to protect their private accounts. In addition, we show that small donation amount and small threshold (collective target) can encourage and sustain cooperation. Furthermore, for other parameters fixed, the impacts of group size act differently on the two scenarios because of distinct mechanisms: in the former case where the cost of cooperation depends on the group size, large size of group readily results in defection, while easily maintains cooperation in the latter case where the cost of cooperation is fixed irrespective of the group size. Our theoretical results of the replicator dynamics are in excellent agreement with the individual based simulation results.

White-nose syndrome is likely to extirpate the endangered Indiana bat over large parts of its range

USGS Publications Warehouse

Thogmartin, Wayne E.; Sanders-Reed, Carol A.; Szymanski, Jennifer A.; McKann, Patrick C.; Pruitt, Lori; King, R. Andrew; Runge, Michael C.; Russell, Robin E.

2013-01-01

White-nose syndrome, a novel fungal pathogen spreading quickly through cave-hibernating bat species in east and central North America, is responsible for killing millions of bats. We developed a stochastic, stage-based population model to forecast the population dynamics of the endangered Indiana bat (Myotis sodalis) subject to white-nose syndrome. Our population model explicitly incorporated environmentally imposed annual variability in survival and reproductive rates and demographic stochasticity in predictions of extinction. With observed rates of disease spread, >90% of wintering populations were predicted to experience white-nose syndrome within 20 years, causing the proportion of populations at the quasi-extinction threshold of less than 250 females to increase by 33.9% over 50 years. At the species’ lowest median population level, ca. year 2022, we predicted 13.7% of the initial population to remain, totaling 28,958 females (95% CI = 13,330; 92,335). By 2022, only 12 of the initial 52 wintering populations were expected to possess wintering populations of >250 females. If the species can acquire immunity to the disease, we predict 3.7% of wintering populations to be above 250 females after 50 years (year 2057) after a 69% decline in abundance (from 210,741 to 64,768 [95% CI = 49,386; 85,360] females). At the nadir of projections, we predicted regional quasi-extirpation of wintering populations in 2 of 4 Recovery Units while in a third region, where the species is currently most abundant, >95% of the wintering populations were predicted to be below 250 females. Our modeling suggests white-nose syndrome is capable of bringing about severe numerical reduction in population size and local and regional extirpation of the Indiana bat.

A league of their own: demographics, motivations and patterns of use of 1,955 male adult non-medical anabolic steroid users in the United States

PubMed Central

Cohen, Jason; Collins, Rick; Darkes, Jack; Gwartney, Daniel

2007-01-01

Background Rule violations among elite-level sports competitors and tragedies among adolescents have largely defined the issue of non-medical anabolic-androgenic steroid (NMAAS) use for the public and policy makers. However, the predominant and oft-ignored segment of the NMAAS community exists in the general population that is neither participating in competitive sports nor adolescent. A clearer profile of NMAAS users within the general population is an initial step in developing a full understanding of NMAAS use and devising appropriate policy and interventions. This survey sought to provide a more comprehensive profile of NMAAS users by accessing a large sample of user respondents from around the United States. Methods U.S.-based male NMAAS users (n = 1955) were recruited from various Internet websites dedicated to resistance training activities and use of ergogenic substances, mass emails, and print media to participate in a 291-item web-based survey. The Internet was utilized to provide a large and geographically diverse sample with the greatest degree of anonymity to facilitate participation. Results The majority of respondents did not initiate AAS use during adolescence and their NMAAS use was not motivated by athletics. The typical user was a Caucasian, highly-educated, gainfully employed professional approximately 30 years of age, who was earning an above-average income, was not active in organized sports, and whose use was motivated by increases in skeletal muscle mass, strength, and physical attractiveness. These findings question commonly held views of the typical NMAAS user and the associated underlying motivations. Conclusion The focus on "cheating" athletes and at risk youth has led to ineffective policy as it relates to the predominant group of NMAAS users. Effective policy, prevention or intervention should address the target population(s) and their reasons for use while utilizing their desire for responsible use and education. PMID:17931410

Effects of Dynamical Evolution on Globular Clusters’ Internal Kinematics

NASA Astrophysics Data System (ADS)

Tiongco, Maria; Vesperini, Enrico; Varri, Anna Lisa

2018-01-01

The synergy between recent photometric, spectroscopic, and astrometric studies is revealing that globular clusters deviate from the traditional picture of dynamically simple and single stellar population systems. Complex kinematical features such as velocity anisotropy and rotation, and the existence of multiple stellar populations are some of the key observational findings. My thesis work has aimed to build a theoretical framework to interpret these new observational results and to understand their link with a globular cluster’s dynamical history.I have focused on the study of the evolution of globular clusters' internal kinematics, as driven by two-body relaxation, and the interplay between internal angular momentum and the external Galactic tidal field. With a specifically-designed, large survey of direct N-body simulations, I have explored the three-dimensional structure of the velocity space of tidally-perturbed clusters, by characterizing their degree of anisotropy and their rotational properties. These studies have proved that a cluster's kinematical properties contain a distinct imprints of the cluster’s initial structural properties, dynamical history, and tidal environment. By relaxing a number of simplifying assumptions that are traditionally imposed, I have also showed how the interplay between a cluster's internal evolution and the interaction with the host galaxy can produce complex morphological and kinematical properties, such as a counter-rotating core and a twisting of the projected isodensity contours.Building on this fundamental understanding, I have then studied the dynamics of multiple stellar populations in globular clusters, with attention to the largely unexplored role of angular momentum. I have analyzed the evolution of clusters with stellar populations characterized by different initial structural and kinematical properties to determine how long these differences are preserved, and in what cases they could still be observable in present-day systems.This body of results provides essential guidance for a meaningful interpretation of the emerging dynamical complexity of globular clusters in the era of Gaia and other upcoming large spectroscopic surveys.

Robust and fast nonlinear optimization of diffusion MRI microstructure models.

PubMed

Harms, R L; Fritz, F J; Tobisch, A; Goebel, R; Roebroeck, A

2017-07-15

Advances in biophysical multi-compartment modeling for diffusion MRI (dMRI) have gained popularity because of greater specificity than DTI in relating the dMRI signal to underlying cellular microstructure. A large range of these diffusion microstructure models have been developed and each of the popular models comes with its own, often different, optimization algorithm, noise model and initialization strategy to estimate its parameter maps. Since data fit, accuracy and precision is hard to verify, this creates additional challenges to comparability and generalization of results from diffusion microstructure models. In addition, non-linear optimization is computationally expensive leading to very long run times, which can be prohibitive in large group or population studies. In this technical note we investigate the performance of several optimization algorithms and initialization strategies over a few of the most popular diffusion microstructure models, including NODDI and CHARMED. We evaluate whether a single well performing optimization approach exists that could be applied to many models and would equate both run time and fit aspects. All models, algorithms and strategies were implemented on the Graphics Processing Unit (GPU) to remove run time constraints, with which we achieve whole brain dataset fits in seconds to minutes. We then evaluated fit, accuracy, precision and run time for different models of differing complexity against three common optimization algorithms and three parameter initialization strategies. Variability of the achieved quality of fit in actual data was evaluated on ten subjects of each of two population studies with a different acquisition protocol. We find that optimization algorithms and multi-step optimization approaches have a considerable influence on performance and stability over subjects and over acquisition protocols. The gradient-free Powell conjugate-direction algorithm was found to outperform other common algorithms in terms of run time, fit, accuracy and precision. Parameter initialization approaches were found to be relevant especially for more complex models, such as those involving several fiber orientations per voxel. For these, a fitting cascade initializing or fixing parameter values in a later optimization step from simpler models in an earlier optimization step further improved run time, fit, accuracy and precision compared to a single step fit. This establishes and makes available standards by which robust fit and accuracy can be achieved in shorter run times. This is especially relevant for the use of diffusion microstructure modeling in large group or population studies and in combining microstructure parameter maps with tractography results. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

News media coverage of smoking and health is associated with changes in population rates of smoking cessation but not initiation.

PubMed

Pierce, J P; Gilpin, E A

2001-06-01

To determine whether changes in news media coverage of smoking and health issues are associated with changes in smoking behaviour in the USA. Issue importance in the US news media is assessed by the number of articles published annually in major magazines indexed in The Reader's Guide to Periodical Literature. Annual incidence rates for cessation and initiation in the USA were computed from the large, representative National Health Interview Surveys (1965-1992). Patterns in cessation incidence were considered for ages 20-34 years and 35-50 years. Initiation incidence was examined for adolescents (14-17 years) and young adults (18-21 years) of both sexes. From 1950 to the early 1980s, the annual incidence of cessation in the USA mirrored the pattern of news media coverage of smoking and health, particularly for middle aged smokers. Cessation rates in younger adults increased considerably when second hand smoke concerns started to increase in the US population. Incidence of initiation in young adults did not start to decline until the beginning of the public health campaign against smoking in the 1960s. Among adolescents, incidence rates did not start to decline until the 1970s, after the broadcast ban on cigarette advertising. The level of coverage of smoking and health in the news media may play an important role in determining the rate of population smoking cessation, but not initiation. In countries where cessation has lagged, advocates should work to increase the newsworthiness of smoking and health issues.

Baseline genetic associations in the Parkinson's Progression Markers Initiative (PPMI).

PubMed

Nalls, Mike A; Keller, Margaux F; Hernandez, Dena G; Chen, Lan; Stone, David J; Singleton, Andrew B

2016-01-01

The Parkinson's Progression Marker Initiative is an international multicenter study whose main goal is investigating markers for Parkinson's disease (PD) progression as part of a path to a treatment for the disease. This manuscript describes the baseline genetic architecture of this study, providing not only a catalog of disease-linked variants and mutations, but also quantitative measures with which to adjust for population structure. Three hundred eighty-three newly diagnosed typical PD cases, 65 atypical PD and 178 healthy controls, from the Parkinson's Progression Marker Initiative study have been genotyped on the NeuroX or Immunochip arrays. These data are freely available to all researchers interested in pursuing PD research within the Parkinson's Progression Marker Initiative. The Parkinson's Progression Marker Initiative represents a study population with low genetic heterogeneity. We recapitulate known PD associations from large-scale genome-wide association studies and refine genetic risk score models for PD predictability (area under the curve, ∼0.74). We show the presence of six LRRK2 p.G2019S and nine GBA p.N370S mutation carriers. The Parkinson's Progression Marker Initiative study and its genetic data are useful in studies of PD biomarkers. The genetic architecture described here will be useful in the analysis of myriad biological and clinical traits within this study. © 2015 International Parkinson and Movement Disorder Society.

Mutant number distribution in an exponentially growing population

NASA Astrophysics Data System (ADS)

Keller, Peter; Antal, Tibor

2015-01-01

We present an explicit solution to a classic model of cell-population growth introduced by Luria and Delbrück (1943 Genetics 28 491-511) 70 years ago to study the emergence of mutations in bacterial populations. In this model a wild-type population is assumed to grow exponentially in a deterministic fashion. Proportional to the wild-type population size, mutants arrive randomly and initiate new sub-populations of mutants that grow stochastically according to a supercritical birth and death process. We give an exact expression for the generating function of the total number of mutants at a given wild-type population size. We present a simple expression for the probability of finding no mutants, and a recursion formula for the probability of finding a given number of mutants. In the ‘large population-small mutation’ limit we recover recent results of Kessler and Levine (2014 J. Stat. Phys. doi:10.1007/s10955-014-1143-3) for a fully stochastic version of the process.

Current CRISPR gene drive systems are likely to be highly invasive in wild populations.

PubMed

Noble, Charleston; Adlam, Ben; Church, George M; Esvelt, Kevin M; Nowak, Martin A

2018-06-19

Recent reports have suggested that self-propagating CRISPR-based gene drive systems are unlikely to efficiently invade wild populations due to drive-resistant alleles that prevent cutting. Here we develop mathematical models based on existing empirical data to explicitly test this assumption for population alteration drives. Our models show that although resistance prevents spread to fixation in large populations, even the least effective drive systems reported to date are likely to be highly invasive. Releasing a small number of organisms will often cause invasion of the local population, followed by invasion of additional populations connected by very low rates of gene flow. Hence, initiating contained field trials as tentatively endorsed by the National Academies report on gene drive could potentially result in unintended spread to additional populations. Our mathematical results suggest that self-propagating gene drive is best suited to applications such as malaria prevention that seek to affect all wild populations of the target species. © 2018, Noble et al.

Selection of G1 Phase Yeast Cells for Synchronous Meiosis and Sporulation.

PubMed

Stuart, David T

2017-01-01

Centrifugal elutriation is a procedure that allows the fractionation of cell populations based upon their size and shape. This allows cells in distinct cell cycle stages can be captured from an asynchronous population. The technique is particularly helpful when performing an experiment to monitor the progression of cells through the cell cycle or meiosis. Yeast sporulation like gametogenesis in other eukaryotes initiates from the G1 phase of the cell cycle. Conveniently, S. cerevisiae arrest in G1 phase when starved for nutrients and so withdrawal of nitrogen and glucose allows cells to abandon vegetative growth in G1 phase before initiating the sporulation program. This simple starvation protocol yields a partial synchronization that has been used extensively in studies of progression through meiosis and sporulation. By using centrifugal elutriation it is possible to isolate a homogeneous population of G1 phase cells and induce them to sporulate synchronously, which is beneficial for investigating progression through meiosis and sporulation. An additionally benefit of this protocol is that cell populations can be isolated based upon size and both large and small cell populations can be tested for progression through meiosis and sporulation. Here we present a protocol for purification of G1 phase diploid cells for examining synchronous progression through meiosis and sporulation.

Within-site variability in surveys of wildlife populations

USGS Publications Warehouse

Link, William A.; Barker, Richard J.; Sauer, John R.; Droege, Sam

1994-01-01

Most large-scale surveys of animal populations are based on counts of individuals observed during a sampling period, which are used as indexes to the population. The variability in these indexes not only reflects variability in population sizes among sites but also variability due to the inexactness of the counts. Repeated counts at survey sites can be used to document this additional source of variability and, in some applications, to mitigate its effects. We present models for evaluating the proportion of total variability in counts that is attributable to this within-site variability and apply them in the analysis of data from repeated counts on routes from the North American Breeding Bird Survey. We analyzed data on 98 species, obtaining estimates of these percentages, which ranged from 3.5 to 100% with a mean of 36.25%. For at least 14 of the species, more than half of the variation in counts was attributable to within-site sources. Counts for species with lower average counts had a higher percentage of within-site variability. We discuss the relative cost efficiency of replicating sites or initiating new sites for several objectives, concluding that it is frequently better to initiate new sites than to attempt to replicate existing sites.

Introduction to the focus section on the 2015 Gorkha, Nepal, earthquake

USGS Publications Warehouse

Hough, Susan E.

2015-01-01

It has long been recognized that Nepal faces high earthquake hazard, with the most recent large (Mw>7.5) events in 1833 and 1934. When the 25 April 2015Mw 7.8 Gorkha earthquake struck, it appeared initially to be a realization of worst fears. In spite of its large magnitude and proximity to the densely populated Kathmandu valley, however, the level of damage was lower than anticipated, with most vernacular structures within the valley experiencing little or no structural damage. Outside the valley, catastrophic damage did occur in some villages, associated with the high vulnerability of stone masonry construction and, in many cases, landsliding. The unexpected observations from this expected earthquake provide an urgent impetus to understand the event itself and to better characterize hazard from future large Himalayan earthquakes. Toward this end, articles in this special focus section present and describe available data sets and initial results that better illuminate and interpret the earthquake and its effects.

Effects of payoff functions and preference distributions in an adaptive population

NASA Astrophysics Data System (ADS)

Yang, H. M.; Ting, Y. S.; Wong, K. Y. Michael

2008-03-01

Adaptive populations such as those in financial markets and distributed control can be modeled by the Minority Game. We consider how their dynamics depends on the agents’ initial preferences of strategies, when the agents use linear or quadratic payoff functions to evaluate their strategies. We find that the fluctuations of the population making certain decisions (the volatility) depends on the diversity of the distribution of the initial preferences of strategies. When the diversity decreases, more agents tend to adapt their strategies together. In systems with linear payoffs, this results in dynamical transitions from vanishing volatility to a nonvanishing one. For low signal dimensions, the dynamical transitions for the different signals do not take place at the same critical diversity. Rather, a cascade of dynamical transitions takes place when the diversity is reduced. In contrast, no phase transitions are found in systems with the quadratic payoffs. Instead, a basin boundary of attraction separates two groups of samples in the space of the agents’ decisions. Initial states inside this boundary converge to small volatility, while those outside diverge to a large one. Furthermore, when the preference distribution becomes more polarized, the dynamics becomes more erratic. All the above results are supported by good agreement between simulations and theory.

The evolving drug development landscape: from blockbusters to niche busters in the orphan drug space.

PubMed

Kumar Kakkar, Ashish; Dahiya, Neha

2014-06-01

Strategy, Management and Health Policy Large pharmaceutical companies have traditionally focused on the development of blockbuster drugs that target disease states with large patient populations. However, with large-scale patent expirations and competition from generics and biosimilars, anemic pipelines, escalating clinical trial costs, and global health-care reform, the blockbuster model has become less viable. Orphan drug initiatives and the incentives accompanied by these have fostered renewed research efforts in the area of rare diseases and have led to the approval of more than 400 orphan products. Despite targeting much smaller patient populations, the revenue-generating potential of orphan drugs has been shown to be huge, with a greater return on investment than non-orphan drugs. The success of these "niche buster" therapeutics has led to a renewed interest from "Big Pharma" in the rare disease landscape. This article reviews the key drivers for orphan drug research and development, their profitability, and issues surrounding the emergence of large pharmaceutical firms into the orphan drug space. © 2014 Wiley Periodicals, Inc.

Global classical solvability and stabilization in a two-dimensional chemotaxis-Navier-Stokes system modeling coral fertilization

NASA Astrophysics Data System (ADS)

Espejo, Elio; Winkler, Michael

2018-04-01

The interplay of chemotaxis, convection and reaction terms is studied in the particular framework of a refined model for coral broadcast spawning, consisting of three equations describing the population densities of unfertilized sperms and eggs and the concentration of a chemical released by the latter, coupled to the incompressible Navier-Stokes equations. Under mild assumptions on the initial data, global existence of classical solutions to an associated initial-boundary value problem in bounded planar domains is established. Moreover, all these solutions are shown to approach a spatially homogeneous equilibrium in the large time limit.

Mixed Integer Programming and Heuristic Scheduling for Space Communication Networks

NASA Technical Reports Server (NTRS)

Lee, Charles H.; Cheung, Kar-Ming

2012-01-01

In this paper, we propose to solve the constrained optimization problem in two phases. The first phase uses heuristic methods such as the ant colony method, particle swarming optimization, and genetic algorithm to seek a near optimal solution among a list of feasible initial populations. The final optimal solution can be found by using the solution of the first phase as the initial condition to the SQP algorithm. We demonstrate the above problem formulation and optimization schemes with a large-scale network that includes the DSN ground stations and a number of spacecraft of deep space missions.

Linking resource selection and mortality modeling for population estimation of mountain lions in Montana

USGS Publications Warehouse

Robinson, Hugh S.; Ruth, Toni K.; Gude, Justin A.; Choate, David; DeSimone, Rich; Hebblewhite, Mark; Matchett, Marc R.; Mitchell, Michael S.; Murphy, Kerry; Williams, Jim

2015-01-01

To be most effective, the scale of wildlife management practices should match the range of a particular species’ movements. For this reason, combined with our inability to rigorously or regularly census mountain lion populations, several authors have suggested that mountain lions be managed in a source-sink or metapopulation framework. We used a combination of resource selection functions, mortality estimation, and dispersal modeling to estimate cougar population levels in Montana statewide and potential population level effects of planned harvest levels. Between 1980 and 2012, 236 independent mountain lions were collared and monitored for research in Montana. From these data we used 18,695 GPS locations collected during winter from 85 animals to develop a resource selection function (RSF), and 11,726 VHF and GPS locations from 142 animals along with the locations of 6343 mountain lions harvested from 1988–2011 to validate the RSF model. Our RSF model validated well in all portions of the State, although it appeared to perform better in Montana Fish, Wildlife and Parks (MFWP) Regions 1, 2, 4 and 6, than in Regions 3, 5, and 7. Our mean RSF based population estimate for the total population (kittens, juveniles, and adults) of mountain lions in Montana in 2005 was 3926, with almost 25% of the entire population in MFWP Region 1. Estimates based on a high and low reference population estimates produce a possible range of 2784 to 5156 mountain lions statewide. Based on a range of possible survival rates we estimated the mountain lion population in Montana to be stable to slightly increasing between 2005 and 2010 with lambda ranging from 0.999 (SD = 0.05) to 1.02 (SD = 0.03). We believe these population growth rates to be a conservative estimate of true population growth. Our model suggests that proposed changes to female harvest quotas for 2013–2015 will result in an annual statewide population decline of 3% and shows that, due to reduced dispersal, changes to harvest in one management unit may affect population growth in neighboring units where smaller or even no changes were made. Uncertainty regarding dispersal levels and initial population density may have a significant effect on predictions at a management unit scale (i.e. 2000 km2), while at a regional scale (i.e. 50,000 km2) large differences in initial population density result in relatively small changes in population growth rate, and uncertainty about dispersal may not be as influential. Doubling the presumed initial density from a low estimation of 2.19 total animals per 100 km2 resulted in a difference in annual population growth rate of only 2.6% statewide when compared to high density of 4.04 total animals per 100 km2 (low initial population estimate λ = 0.99, while high initial population estimate λ = 1.03). We suggest modeling tools such as this may be useful in harvest planning at a regional and statewide level.

Population cage experiments with a vertebrate: The temporal demography and cytonuclear genetics of hybridization on Gambusia fishes

USGS Publications Warehouse

Scribner, Kim T.; Avise, John C.

1994-01-01

The dynamics of mitochondrial and multilocus nuclear genotypic frequencies were monitored for 2 yr in experimental populations established with equal numbers of two poeciliid fishes (Gambusia affinis and Gambusia holbrooki) that hybridize naturally in the southeastern United States. In replicated "small-pool" populations (experiment I), 1018 sampled individuals at six time periods revealed an initial flush of hybridization, followed by a rapid decline in frequencies of G. affinis nuclear and mitochondrial alleles over 64 wk. Decay of gametic and cytonuclear disequilibria differed from expectations under random mating as well as under a model of assortative mating involving empirically estimated mating propensities. In two replicate "large-pond" populations (experiment II), 841 sampled individuals across four reproductive cohorts revealed lower initial frequencies of F1 hybrids than in experiment I, but again G. holbrooki alleles achieved high frequencies over four generations (72 wk). Thus, evolution within experimental Gambusia hybrid populations can be extremely rapid, resulting in consistent loss of G. affinis nuclear and cytoplasmic alleles. Concordance in results between experiments and across genetic markers suggests strong directional selection favoring G. holbrooki genotypes. Results are interpreted in light of previous reports of genotype-specific differences in life-history traits, reproductive ecology, patterns of recruitment, and size-specific mortality, and in the context of patterns of introgression previously studied indirectly from spatial observations on cytonuclear genotypes in natural Gambusia populations.

Strain memory of 2D and 3D rigid inclusion populations in viscous flows - What is clast SPO telling us?

NASA Astrophysics Data System (ADS)

Stahr, Donald W.; Law, Richard D.

2014-11-01

We model the development of shape preferred orientation (SPO) of a large population of two- and three-dimensional (2D and 3D) rigid clasts suspended in a linear viscous matrix deformed by superposed steady and continuously non-steady plane strain flows to investigate the sensitivity of clasts to changing boundary conditions during a single or superposed deformation events. Resultant clast SPOs are compared to one developed by an identical initial population that experienced a steady flow history of constant kinematic vorticity and reached an identical finite strain state, allowing examination of SPO sensitivity to deformation path. Rotation paths of individual triaxial inclusions are complex, even for steady plane strain flow histories. It has been suggested that the 3D nature of the system renders predictions based on 2D models inadequate for applied clast-based kinematic vorticity gauges. We demonstrate that for a large population of clasts, simplification to a 2D model does provide a good approximation to the SPO predicted by full 3D analysis for steady and non-steady plane strain deformation paths. Predictions of shape fabric development from 2D models are not only qualitatively similar to the more complex 3D analysis, but they display the same limitations of techniques based on clast SPO commonly used as a quantitative kinematic vorticity gauge. Our model results from steady, superposed, and non-steady flow histories with a significant pure shearing component at a wide range of finite strain resemble predictions for an identical initial population that experienced a single steady simple shearing deformation. We conclude that individual 2D and 3D clasts respond instantaneously to changes in boundary conditions, however, in aggregate, the SPO of a population of rigid inclusions does not reflect the late-stage kinematics of deformation, nor is it an indicator of the unique 'mean' kinematic vorticity experienced by a deformed rock volume.

KCTF evolution of trans-neptunian binaries: Connecting formation to observation

NASA Astrophysics Data System (ADS)

Porter, Simon B.; Grundy, William M.

2012-08-01

Recent observational surveys of trans-neptunian binary (TNB) systems have dramatically increased the number of known mutual orbits. Our Kozai Cycle Tidal Friction (KCTF) simulations of synthetic trans-neptunian binaries show that tidal dissipation in these systems can completely reshape their original orbits. Specifically, solar torques should have dramatically accelerated the semimajor axis decay and circularization timescales of primordial (or recently excited) TNBs. As a result, our initially random distribution of TNBs in our simulations evolved to have a large population of tight circular orbits. This tight circular population appears for a range of TNO physical properties, though a strong gravitational quadrupole can prevent some from fully circularizing. We introduce a stability parameter to predict the effectiveness of KCTF on a TNB orbit, and show that a number of known TNBs must have a large gravitational quadrupole to be stable.

Heroin-assisted Treatment (HAT) a Decade Later: A Brief Update on Science and Politics

PubMed Central

Oviedo-Joekes, Eugenia; Blanken, Peter; Haasen, Christian; Rehm, Jürgen; Schechter, Martin T.; Strang, John; van den Brink, Wim

2007-01-01

Since the initial Swiss heroin-assisted treatment (HAT) study conducted in the mid-1990s, several other jurisdictions in Europe and North America have implemented HAT trials. All of these studies embrace the same goal—investigating the utility of medical heroin prescribing for problematic opioid users—yet are distinct in various key details. This paper briefly reviews (initiated or completed) studies and their main parameters, including primary research objectives, design, target populations, outcome measures, current status and—where available—key results. We conclude this overview with some final observations on a decade of intensive HAT research in the jurisdictions examined, including the suggestion that there is a mounting onus on the realm of politics to translate the—largely positive—data from completed HAT science into corresponding policy and programming in order to expand effective treatment options for the high-risk population of illicit opioid users. PMID:17562183

Improving sensitivity to magnetic fields and electric dipole moments by using measurements of individual magnetic sublevels

NASA Astrophysics Data System (ADS)

Tang, Cheng; Zhang, Teng; Weiss, David S.

2018-03-01

We explore ways to use the ability to measure the populations of individual magnetic sublevels to improve the sensitivity of magnetic field measurements and measurements of atomic electric dipole moments (EDMs). When atoms are initialized in the m =0 magnetic sublevel, the shot-noise-limited uncertainty of these measurements is 1 /√{2 F (F +1 ) } smaller than that of a Larmor precession measurement. When the populations in the even (or odd) magnetic sublevels are combined, we show that these measurements are independent of the tensor Stark shift and the second order Zeeman shift. We discuss the complicating effect of a transverse magnetic field and show that when the ratio of the tensor Stark shift to the transverse magnetic field is sufficiently large, an EDM measurement with atoms initialized in the superposition of the stretched states can reach the optimal sensitivity.

Modeling human mobility responses to the large-scale spreading of infectious diseases.

PubMed

Meloni, Sandro; Perra, Nicola; Arenas, Alex; Gómez, Sergio; Moreno, Yamir; Vespignani, Alessandro

2011-01-01

Current modeling of infectious diseases allows for the study of realistic scenarios that include population heterogeneity, social structures, and mobility processes down to the individual level. The advances in the realism of epidemic description call for the explicit modeling of individual behavioral responses to the presence of disease within modeling frameworks. Here we formulate and analyze a metapopulation model that incorporates several scenarios of self-initiated behavioral changes into the mobility patterns of individuals. We find that prevalence-based travel limitations do not alter the epidemic invasion threshold. Strikingly, we observe in both synthetic and data-driven numerical simulations that when travelers decide to avoid locations with high levels of prevalence, this self-initiated behavioral change may enhance disease spreading. Our results point out that the real-time availability of information on the disease and the ensuing behavioral changes in the population may produce a negative impact on disease containment and mitigation.

The scaling of contact rates with population density for the infectious disease models.

PubMed

Hu, Hao; Nigmatulina, Karima; Eckhoff, Philip

2013-08-01

Contact rates and patterns among individuals in a geographic area drive transmission of directly-transmitted pathogens, making it essential to understand and estimate contacts for simulation of disease dynamics. Under the uniform mixing assumption, one of two mechanisms is typically used to describe the relation between contact rate and population density: density-dependent or frequency-dependent. Based on existing evidence of population threshold and human mobility patterns, we formulated a spatial contact model to describe the appropriate form of transmission with initial growth at low density and saturation at higher density. We show that the two mechanisms are extreme cases that do not capture real population movement across all scales. Empirical data of human and wildlife diseases indicate that a nonlinear function may work better when looking at the full spectrum of densities. This estimation can be applied to large areas with population mixing in general activities. For crowds with unusually large densities (e.g., transportation terminals, stadiums, or mass gatherings), the lack of organized social contact structure deviates the physical contacts towards a special case of the spatial contact model - the dynamics of kinetic gas molecule collision. In this case, an ideal gas model with van der Waals correction fits well; existing movement observation data and the contact rate between individuals is estimated using kinetic theory. A complete picture of contact rate scaling with population density may help clarify the definition of transmission rates in heterogeneous, large-scale spatial systems. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Medication therapy disease management: Geisinger's approach to population health management.

PubMed

Jones, Laney K; Greskovic, Gerard; Grassi, Dante M; Graham, Jove; Sun, Haiyan; Gionfriddo, Michael R; Murray, Michael F; Manickam, Kandamurugu; Nathanson, Douglas C; Wright, Eric A; Evans, Michael A

2017-09-15

Pharmacists' involvement in a population health initiative focused on chronic disease management is described. Geisinger Health System has cultivated a culture of innovation in population health management, as highlighted by its ambulatory care pharmacy program, the Medication Therapy Disease Management (MTDM) program. Initiated in 1996, the MTDM program leverages pharmacists' pharmacotherapy expertise to optimize care and improve outcomes. MTDM program pharmacists are trained and credentialed to manage over 16 conditions, including atrial fibrillation (AF) and multiple sclerosis (MS). Over a 15-year period, Geisinger Health Plan (GHP)-insured patients with AF whose warfarin therapy was managed by the MTDM program had, on average, 18% fewer emergency department (ED) visits and 18% fewer hospitalizations per year than GHP enrollees with AF who did not receive MTDM services, with 23% lower annual total care costs. Over a 2-year period, GHP-insured patients with MS whose pharmacotherapy was managed by pharmacists averaged 28% fewer annual ED visits than non-pharmacist-managed patients; however, the mean annual total care cost was 21% higher among MTDM clinic patients. The Geisinger MTDM program has evolved over 20 years from a single pharmacist-run anticoagulation clinic into a large program focused on managing the health of an ever-growing population. Initial challenges in integrating pharmacists into the Geisinger patient care framework as clinical experts were overcome by demonstrating the MTDM program's positive impact on patient outcomes. Copyright © 2017 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Early dynamical evolution of young substructured clusters

NASA Astrophysics Data System (ADS)

Dorval, Julien; Boily, Christian

2017-03-01

Stellar clusters form with a high level of substructure, inherited from the molecular cloud and the star formation process. Evidence from observations and simulations also indicate the stars in such young clusters form a subvirial system. The subsequent dynamical evolution can cause important mass loss, ejecting a large part of the birth population in the field. It can also imprint the stellar population and still be inferred from observations of evolved clusters. Nbody simulations allow a better understanding of these early twists and turns, given realistic initial conditions. Nowadays, substructured, clumpy young clusters are usually obtained through pseudo-fractal growth and velocity inheritance. We introduce a new way to create clumpy initial conditions through a ''Hubble expansion'' which naturally produces self consistent clumps, velocity-wise. In depth analysis of the resulting clumps shows consistency with hydrodynamical simulations of young star clusters. We use these initial conditions to investigate the dynamical evolution of young subvirial clusters. We find the collapse to be soft, with hierarchical merging leading to a high level of mass segregation. The subsequent evolution is less pronounced than the equilibrium achieved from a cold collapse formation scenario.

How Genes Have Illuminated the History of Early Americans and Latino Americans

PubMed Central

Ruiz-Linares, Andrés

2015-01-01

The American continent currently accounts for ∼15% of the world population. Although first settled thousands of years ago and fitting its label as “the New World,” the European colonial expansion initiated in the late 15th century resulted in people from virtually every corner of the globe subsequently settling in the Americas. The arrival of large numbers of immigrants led to a dramatic decline of the Native American population and extensive population mixing. A salient feature of the current human population of the Americas is, thus, its great diversity. The genetic variation of the Native peoples that recent immigrants encountered had been shaped by demographic events acting since the initial peopling of the continent. Similarly, but on a compressed timescale, the colonial history of the Americas has had a major impact on the genetic makeup of the current population of the continent. A range of genetic analyses has been used to study both the ancient settlement of the continent and more recent history of population mixing. Here, I show how these two strands of research overlap and make use of results from other scientific disciplines to produce a fuller picture of the settlement of the continent at different time periods. The biological diversity of the Americas also provides prominent examples of the complex interaction between biological and social factors in constructing human identities and of the difficulties in defining human populations. PMID:25256008

Modeling multilayer x-ray reflectivity using genetic algorithms

NASA Astrophysics Data System (ADS)

Sánchez del Río, M.; Pareschi, G.; Michetschläger, C.

2000-06-01

The x-ray reflectivity of a multilayer is a non-linear function of many parameters (materials, layer thickness, density, roughness). Non-linear fitting of experimental data with simulations requires the use of initial values sufficiently close to the optimum value. This is a difficult task when the topology of the space of the variables is highly structured. We apply global optimization methods to fit multilayer reflectivity. Genetic algorithms are stochastic methods based on the model of natural evolution: the improvement of a population along successive generations. A complete set of initial parameters constitutes an individual. The population is a collection of individuals. Each generation is built from the parent generation by applying some operators (selection, crossover, mutation, etc.) on the members of the parent generation. The pressure of selection drives the population to include "good" individuals. For large number of generations, the best individuals will approximate the optimum parameters. Some results on fitting experimental hard x-ray reflectivity data for Ni/C and W/Si multilayers using genetic algorithms are presented. This method can also be applied to design multilayers optimized for a target application.

Intersections and evolution of 'Butch-trans' categories in Puerto Rico: Needs and barriers of an invisible population.

PubMed

Ramos-Pibernus, Alíxida G; Rodríguez-Madera, Sheilla L; Padilla, Mark; Varas-Díaz, Nelson; Vargas Molina, Ricardo

2016-01-01

Public health research among transgender populations globally has primarily focused on HIV/AIDS. However, trans men remain outside of this conceptual framework, with distinct but overlapping social contexts and needs. In Puerto Rico (PR), the trans men population has remained largely hidden within the 'butch' lesbian community. The objective of this article is to document the identity construction of trans men and 'buchas' (local term to refer to butch lesbians) in PR and its relation to their bodily practices and overall health. We conducted an exploratory qualitative study with 29 trans men and buchas based on ethnographic observation, focus groups, audio-recorded in-depth interviews, and critical discourse analysis. Findings emphasise two domains to be addressed by health policies and initiatives: (1) bodily representations and gender performance, and (2) the meanings of female biological processes. This small-scale ethnographic study represents an initial step towards understanding the social context of this 'invisible' community and significant implications for their health and well-being. We provide several recommendations to address public health concerns of this understudied, marginalised community.

Intersections and evolution of ‘Butch-trans’ categories in Puerto Rico: Needs and barriers of an invisible population

PubMed Central

Ramos-Pibernus, Alíxida G.; Rodríguez-Madera, Sheilla L.; Padilla, Mark; Varas-Díaz, Nelson; Molina, Ricardo Vargas

2016-01-01

Public health research among transgender populations globally has primarily focused on HIV/AIDS. However, trans men remain outside of this conceptual framework, with distinct but overlapping social contexts and needs. In Puerto Rico (PR), the trans men population has remained largely hidden within the ‘butch’ lesbian community. The objective of this article is to document the identity construction of trans men and ‘buchas’ (local term to refer to butch lesbians) in PR and its relation to their bodily practices and overall health. We conducted an exploratory qualitative study with 29 trans men and buchas based on ethnographic observation; focus groups; audio-recorded in-depth interviews; and critical discourse analysis. Findings emphasize two domains to be addressed by health policies and initiatives: 1) bodily representations and gender performance, and 2) the meanings of female biological processes. This small-scale ethnographic study represents an initial step toward understanding the social context of this ‘invisible’ community and significant implications for their health and well-being. We provide several recommendations to address public health concerns of this understudied, marginalized community. PMID:27142002

Integrating family planning with other social services.

PubMed

Bernales, E H

1982-01-01

Family planning outreach workers in the 43 municipalities of Iloilo Province, Western Visayas, the Philippines, have provided their communities with health, nutrition, educational, and agricultural services since 1973, when the Provincial Development Staff (PDS) began attempting to integrate services. The early work of the PDS was aided by the launching of the National Population and Family Planning Outreach Project in rural areas in 1976 and the creation of the Provincial Population Office (PPO) in 1977. 43% of the Outreach Project cost is borne by the local government, with the Commission on Population covering the rest. It is anticipated that the local goverment will eventually absorb the full cost. The Outreach officers have become an integral part of the planning body of the provincial government, largely due to the creation of the Provincial Consultative Committee on Population (PCCP) in 1979. The PCCP, composed of 22 governmental and private agencies involved in population-related activities, is charged with implementing the national population program in order to utilize all possible resources for provincial development. Its Integrated Provincial Population Plan has become part of the total provincial development plan. The Municipal Population Planning Actions Teams, whose functions are patterned on those of the PCCPs, further strengthen local planning at the municipal level. Full-Time Outreach Workers participate as well in planning at the barangay level. The various community-based projects initiated by the Outreach staff in Iloilo demonstrate a concern with making the population program responsive to the immediate needs of the provincial population. Organizations which teach better farming methods and undertake community projects emphasize local initiative and solutions to problems, and demonstrate the committment of population workers to broader development efforts. Outreach workers are involved in primary health care, social service delivery, income generating projects, and other activities even in backward and inaccessible areas.

Population-specific demographic estimates provide insights into declines of Lark Buntings (Calamospiza melanocorys)

USGS Publications Warehouse

Yackel Adams, A.A.; Skagen, S.K.; Savidge, J.A.

2007-01-01

Many North American prairie bird populations have recently declined, and the causes of these declines remain largely unknown. To determine whether population limitation occurs during breeding, we evaluated the stability of a population of prairie birds using population-specific values for fecundity and postfledging survival. During 2001-2003, we radiomarked 67 female Lark Buntings (Calamospiza melanocorys) to determine annual fecundity and evaluate contributing factors such as nest survival and breeding response (number of breeding attempts and dispersal). Collectively, 67 females built 112 nests (1.67 ± 0.07 nests female−1 season−1; range: 1–3); 34 were second nests and 11 were third nests. Daily nest survival estimates were similar for initial and later nests with overall nest survival (DSR19) of 30.7% and 31.7%, respectively. Nest predation was the most common cause of failure (92%). Capture and radiomarking of females did not affect nest survival. Lark Bunting dispersal probabilities increased among females that fledged young from initial nests and females that lost their original nests late in the season. Conservative and liberal estimates of mean annual fecundity were 0.96 ±0.11 and 1.24 ± 0.09 female offspring per female, respectively. Given the fecundity and juvenile-survival estimates for this population, annual adult survival values of 71–77% are necessary to achieve a stable population. Because adult survival of prairie passerines ranges between 55% and 65%, this study area may not be capable of sustaining a stable population in the absence of immigration. We contrast our population assessment with one that assumes indirect values of fecundity and juvenile survival. To elucidate limiting factors, estimation of population-specific demographic parameters is desirable. We present an approach for selecting species and areas for evaluation of population stability.

The link between poverty, environment and development. The political challenge of localizing Agenda 21.

PubMed

Wichmann, R

1995-11-01

This article discusses the links between poverty, development, the environment, and implementing Agenda 21. The poor in large cities experience greater health risks and threats from environmental hazards. The poor also face inadequate housing, poor sanitation, polluted drinking water, and lack of other basic services. Many poor live in marginalized areas more susceptible to environmental degradation. During 1990-2030, population size may reach 9.7 billion, or 3.7 billion more than today. 90% may be urban residents. Already a large proportion of urban population live in a decaying urban environment with health and life threatening conditions. At least 250 million do not have easy access to safe piped water. 400 million lack proper sanitation. The liberalization of the global economy is fueling urbanization. The cycle of poverty and environmental decline requires rapid economic growth and closing of the infrastructure gaps. Policy initiatives of Agenda 21 occur at the local urban level. At this level, policies directly affect people. The future success of Agenda 21 will depend on local initiatives. Management approaches may need to change in order to achieve sustainable development. The poor will be more vocal and heard from in the future. Critical areas of management include waste management, pollution control, traffic, transportation, energy, economic development, and job creation. Society must be able to participate in setting priorities. About 1500 local authorities are involved in Agenda 21 planning initiatives. Curitiba, Brazil, is an example of how cities can solve community problems.

Waterbird conservation planning in the northern prairie and parkland region: Integration across borders and with other bird conservation initiatives

Treesearch

Neal D. Niemuth; Gerard W. Beyersbergen; Michael R. Norton

2005-01-01

The Northern Prairie and Parkland Region contain millions of wetland basins, which harbor large proportions of the populations of many North American waterbird species, several of which are of high conservation concern. However, knowledge of waterbirds in the region is limited, and there has been little direction for waterbird conservation planning or management. The...

Case report of an 11-year-old child with a nonfunctional malignant pheochromocytoma.

PubMed

Holwitt, Dana; Neifeld, James; Massey, Gita; Lanning, David

2007-11-01

Pheochromocytoma is an unusual cause of surgical hypertension and is extremely rare in the pediatric population. We present a case of a hypertension-producing malignant pheochromocytoma in an 11-year-old, which was initially unresectable. The tumor responded partially to aggressive chemotherapy and was completely resected. This approach highlights the importance of multidisciplinary care for patients with large pheochromocytomas.

Finding the Openings Amid the Closings: One School's Approach to Taking Ownership of Teaching and Learning

ERIC Educational Resources Information Center

King, Fiona; Feeley, Úna

2014-01-01

Education is in challenging times, largely due to economic cutbacks on the one hand and growing demands on teachers to meet the needs of an increasingly diverse student population on the other. Given these constraints, teachers' desire and self-confidence to initiate and use their own imaginations to meet the diverse needs of their students is…

Use of histamine H2 receptor antagonists and outcomes in patients with heart failure: a nationwide population-based cohort study.

PubMed

Adelborg, Kasper; Sundbøll, Jens; Schmidt, Morten; Bøtker, Hans Erik; Weiss, Noel S; Pedersen, Lars; Sørensen, Henrik Toft

2018-01-01

Histamine H 2 receptor activation promotes cardiac fibrosis and apoptosis in mice. However, the potential effectiveness of histamine H 2 receptor antagonists (H2RAs) in humans with heart failure is largely unknown. We examined the association between H2RA initiation and all-cause mortality among patients with heart failure. Using Danish medical registries, we conducted a nationwide population-based active-comparator cohort study of new users of H2RAs and proton pump inhibitors (PPIs) after first-time hospitalization for heart failure during the period 1995-2014. Hazard ratios (HRs) for all-cause mortality and hospitalization due to worsening of heart failure, adjusting for age, sex, and time between heart failure diagnosis and initiation of PPI or H2RA therapy, index year, comorbidity, cardiac surgery, comedications, and socioeconomic status were computed based on Cox regression analysis. Our analysis included 42,902 PPI initiators (median age 78 years, 46% female) and 3,296 H2RA initiators (median age 76 years, 48% female). Mortality risk was lower among H2RA initiators than PPI initiators after 1 year (26% vs 31%) and 5 years (60% vs 66%). In multivariable analyses, the 1-year HR was 0.80 (95% CI, 0.74-0.86) and the 5-year HR was 0.85 (95% CI, 0.80-0.89). These findings were consistent after propensity score matching and for ischemic and nonischemic heart failure, as for sex and age groups. The rate of hospitalization due to worsening of heart failure was lower among H2RA initiators than PPI initiators. In patients with heart failure, H2RA initiation was associated with 15%-20% lower mortality than PPI initiation.

Targeted Recombinant Progeny: a design for ultra-high resolution mapping of Quantitative Trait Loci in crosses between inbred or pure lines.

PubMed

Heifetz, Eliyahu M; Soller, Morris

2015-07-07

High-resolution mapping of the loci (QTN) responsible for genetic variation in quantitative traits is essential for positional cloning of candidate genes, and for effective marker assisted selection. The confidence interval (QTL) flanking the point estimate of QTN-location is proportional to the number of individuals in the mapping population carrying chromosomes recombinant in the given interval. Consequently, many designs for high resolution QTN mapping are based on increasing the proportion of recombinants in the mapping population. The "Targeted Recombinant Progeny" (TRP) design is a new design for high resolution mapping of a target QTN in crosses between pure, or inbred lines. It is a three-generation procedure generating a large number of recombinant individuals within a QTL previously shown to contain a QTN. This is achieved by having individuals that carry chromosomes recombinant across the target QTL interval as parents of a large mapping population; most of whom will therefore carry recombinant chromosomes targeted to the given QTL. The TRP design is particularly useful for high resolution mapping of QTN that differentiate inbred or pure lines, and hence are not amenable to high resolution mapping by genome-wide association tests. In the absence of residual polygenic variation, population sizes required for achieving given mapping resolution by the TRP-F2 design relative to a standard F2 design ranged from 0.289 for a QTN with standardized allele substitution effect = 0.2, mapped to an initial QTL of 0.2 Morgan to 0.041 for equivalent QTN mapped to an initial QTL of 0.02 M. In the presence of residual polygenic variation, the relative effectiveness of the TRP design ranges from 1.068 to 0.151 for the same initial QTL intervals and QTN effect. Thus even in the presence of polygenic variation, the TRP can still provide major savings. Simulation showed that mapping by TRP should be based on 30-50 markers spanning the initial interval; and on at least 50 or more G2 families representing this number of recombination points,. The TRP design can be an effective procedure for achieving high and ultra-high mapping resolution of a target QTN previously mapped to a known confidence interval (QTL).

Population-expression models of immune response

NASA Astrophysics Data System (ADS)

Stromberg, Sean P.; Antia, Rustom; Nemenman, Ilya

2013-06-01

The immune response to a pathogen has two basic features. The first is the expansion of a few pathogen-specific cells to form a population large enough to control the pathogen. The second is the process of differentiation of cells from an initial naive phenotype to an effector phenotype which controls the pathogen, and subsequently to a memory phenotype that is maintained and responsible for long-term protection. The expansion and the differentiation have been considered largely independently. Changes in cell populations are typically described using ecologically based ordinary differential equation models. In contrast, differentiation of single cells is studied within systems biology and is frequently modeled by considering changes in gene and protein expression in individual cells. Recent advances in experimental systems biology make available for the first time data to allow the coupling of population and high dimensional expression data of immune cells during infections. Here we describe and develop population-expression models which integrate these two processes into systems biology on the multicellular level. When translated into mathematical equations, these models result in non-conservative, non-local advection-diffusion equations. We describe situations where the population-expression approach can make correct inference from data while previous modeling approaches based on common simplifying assumptions would fail. We also explore how model reduction techniques can be used to build population-expression models, minimizing the complexity of the model while keeping the essential features of the system. While we consider problems in immunology in this paper, we expect population-expression models to be more broadly applicable.

Intraspecific competition and density dependence of food consumption and growth in Arctic charr.

PubMed

Amundsen, Per-Arne; Knudsen, Rune; Klemetsen, Anders

2007-01-01

1. Intraspecific competition for restricted food resources is considered to play a fundamental part in density dependence of somatic growth and other population characteristics, but studies simultaneously addressing the interrelationships between population density, food acquisition and somatic growth have been missing. 2. We explored the food consumption and individual growth rates of Arctic charr Salvelinus alpinus in a long-term survey following a large-scale density manipulation experiment in a subarctic lake. 3. Prior to the initiation of the experiment, the population density was high and the somatic growth rates low, revealing a severely overcrowded and stunted fish population. 4. During the 6-year period of stock depletion the population density of Arctic charr was reduced with about 75%, resulting in an almost twofold increase in food consumption rates and enhanced individual growth rates of the fish. 5. Over the decade following the density manipulation experiment, the population density gradually rose to intermediate levels, accompanied by corresponding reductions in food consumption and somatic growth rates. 6. The study revealed negative relationships with population density for both food consumption and individual growth rates, reflecting a strong positive correlation between quantitative food intake and somatic growth rates. 7. Both the growth and consumption rate relationships with population density were well described by negative power curves, suggesting that large density perturbations are necessary to induce improved feeding conditions and growth rates in stunted fish populations. 8. The findings demonstrate that quantitative food consumption represents the connective link between population density and individual growth rates, apparently being highly influenced by intraspecific competition for limited resources.

Comparison of historical bottleneck effects and genetic consequences of re-introduction in a critically endangered island passerine.

PubMed

Bristol, Rachel M; Tucker, Rachel; Dawson, Deborah A; Horsburgh, Gavin; Prys-Jones, Robert P; Frantz, Alain C; Krupa, Andy; Shah, Nirmal J; Burke, Terry; Groombridge, Jim J

2013-09-01

Re-introduction is an important tool for recovering endangered species; however, the magnitude of genetic consequences for re-introduced populations remains largely unknown, in particular the relative impacts of historical population bottlenecks compared to those induced by conservation management. We characterize 14 microsatellite loci developed for the Seychelles paradise flycatcher and use them to quantify temporal and spatial measures of genetic variation across a 134-year time frame encompassing a historical bottleneck that reduced the species to ~28 individuals in the 1960s, through the initial stages of recovery and across a second contemporary conservation-introduction-induced bottleneck. We then evaluate the relative impacts of the two bottlenecks, and finally apply our findings to inform broader re-introduction strategy. We find a temporal trend of significant decrease in standard measures of genetic diversity across the historical bottleneck, but only a nonsignificant downward trend in number of alleles across the contemporary bottleneck. However, accounting for the different timescales of the two bottlenecks (~40 historical generations versus <1 contemporary generation), the loss of genetic diversity per generation is greater across the contemporary bottleneck. Historically, the flycatcher population was genetically structured; however, extinction on four of five islands has resulted in a homogeneous contemporary population. We conclude that severe historical bottlenecks can leave a large footprint in terms of sheer quantity of genetic diversity lost. However, severely depleted genetic diversity does not render a species immune to further genetic erosion upon re-introduction. In some cases, the loss of genetic diversity per generation can, initially at least, be greater across re-introduction-induced bottlenecks. © 2013 John Wiley & Sons Ltd.

The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

PubMed

Erfmeier, Alexandra; Hantsch, Lydia; Bruelheide, Helge

2013-01-01

Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of invasive plants, a clear differentiation between initial emergence and subsequent survival to juvenile and adult stages is required.

The Chernobyl accident and its consequences.

PubMed

Saenko, V; Ivanov, V; Tsyb, A; Bogdanova, T; Tronko, M; Demidchik, Yu; Yamashita, S

2011-05-01

The accident at the Chernobyl nuclear power plant was the worst industrial accident of the last century that involved radiation. The unprecedented release of multiple different radioisotopes led to radioactive contamination of large areas surrounding the accident site. The exposure of the residents of these areas was varied and therefore the consequences for health and radioecology could not be reliably estimated quickly. Even though some studies have now been ongoing for 25 years and have provided a better understanding of the situation, these are yet neither complete nor comprehensive enough to determine the long-term risk. A true assessment can only be provided after following the observed population for their natural lifespan. Here we review the technical aspects of the accident and provide relevant information on radioactive releases that resulted in exposure of this large population to radiation. A number of different groups of people were exposed to radiation: workers involved in the initial clean-up response, and members of the general population who were either evacuated from the settlements in the Chernobyl nuclear power plant vicinity shortly after the accident, or continued to live in the affected territories of Belarus, Russia and Ukraine. Through domestic efforts and extensive international co-operation, essential information on radiation dose and health status for this population has been collected. This has permitted the identification of high-risk groups and the use of more specialised means of collecting information, diagnosis, treatment and follow-up. Because radiation-associated thyroid cancer is one of the major health consequences of the Chernobyl accident, a particular emphasis is placed on this malignancy. The initial epidemiological studies are reviewed, as are the most significant studies and/or aid programmes in the three affected countries. Copyright © 2011 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Early Glycemic Control and Magnitude of HbA1c Reduction Predict Cardiovascular Events and Mortality: Population-Based Cohort Study of 24,752 Metformin Initiators.

PubMed

Svensson, Elisabeth; Baggesen, Lisbeth M; Johnsen, Søren P; Pedersen, Lars; Nørrelund, Helene; Buhl, Esben S; Haase, Christiane L; Thomsen, Reimar W

2017-06-01

We investigated the association of early achieved HbA 1c level and magnitude of HbA 1c reduction with subsequent risk of cardiovascular events or death in patients with type 2 diabetes who initiate metformin. This was a population-based cohort study including all metformin initiators with HbA 1c tests in Northern Denmark, 2000-2012. Six months after metformin initiation, we classified patients by HbA 1c achieved (<6.5% or higher) and by magnitude of HbA 1c change from the pretreatment baseline. We used Cox regression to examine subsequent rates of acute myocardial infarction, stroke, or death, controlling for baseline HbA 1c and other confounding factors. We included 24,752 metformin initiators (median age 62.5 years, 55% males) with a median follow-up of 2.6 years. The risk of a combined outcome event gradually increased with rising levels of HbA 1c achieved compared with a target HbA 1c of <6.5%: adjusted hazard ratio (HR) 1.18 (95% CI 1.07-1.30) for 6.5-6.99%, HR 1.23 (1.09-1.40) for 7.0-7.49%, HR 1.34 (1.14-1.57) for 7.5-7.99%, and HR 1.59 (1.37-1.84) for ≥8%. Results were consistent for individual outcome events and robust by age-group and other patient characteristics. A large absolute HbA 1c reduction from baseline also predicted outcome: adjusted HR 0.80 (0.65-0.97) for Δ = -4, HR 0.98 (0.80-1.20) for Δ = -3, HR 0.92 (0.78-1.08) for Δ = -2, and HR 0.99 (0.89-1.10) for Δ = -1 compared with no HbA 1c change (Δ = 0). A large initial HbA 1c reduction and achievement of low HbA 1c levels within 6 months after metformin initiation are associated with a lower risk of cardiovascular events and death in patients with type 2 diabetes. © 2017 by the American Diabetes Association.

Using Population Dose to Evaluate Community-level Health Initiatives.

PubMed

Harner, Lisa T; Kuo, Elena S; Cheadle, Allen; Rauzon, Suzanne; Schwartz, Pamela M; Parnell, Barbara; Kelly, Cheryl; Solomon, Loel

2018-05-01

Successful community-level health initiatives require implementing an effective portfolio of strategies and understanding their impact on population health. These factors are complicated by the heterogeneity of overlapping multicomponent strategies and availability of population-level data that align with the initiatives. To address these complexities, the population dose methodology was developed for planning and evaluating multicomponent community initiatives. Building on the population dose methodology previously developed, this paper operationalizes dose estimates of one initiative targeting youth physical activity as part of the Kaiser Permanente Community Health Initiative, a multicomponent community-level obesity prevention initiative. The technical details needed to operationalize the population dose method are explained, and the use of population dose as an interim proxy for population-level survey data is introduced. The alignment of the estimated impact from strategy-level data analysis using the dose methodology and the data from the population-level survey suggest that dose is useful for conducting real-time evaluation of multiple heterogeneous strategies, and as a viable proxy for existing population-level surveys when robust strategy-level evaluation data are collected. This article is part of a supplement entitled Building Thriving Communities Through Comprehensive Community Health Initiatives, which is sponsored by Kaiser Permanente, Community Health. Copyright © 2018 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

The population threat.

PubMed

Teitelbaum, M S

1992-01-01

Commentary is provided on the challenges faced by the new Clinton administration in formulating US key foreign policy initiatives. There is an urgent need to provide balanced and effective foreign aid for reducing high fertility rates in the developing world. There is also a need to effectively monitor the large migrations of populations. Over the past 10 years, the US has not been actively practicing world leadership on population issues. 3 changes in 1993 give impetus to redirect foreign policy: 1) the waning influence of fringe groups who controlled population issues; 2) the campaign promises to restore UN population stabilization programs; and 3) the evidence from the Persian Gulf and Yugoslavia that demographic issues require planning and assessment. Global population growth has been concentrated in the past 40 years, in part due to mortality declines and sustained high fertility. Of significance is the rapidness and momentum of growth. A high percentage are and will be children. Urban population is also growing rapidly in high fertility countries. Countries with high fertility and significant rural-to-urban migration also have large international migrations. The evolution of policy since the 1950s, which for the most part ignored population issues, is discussed. The American debates have been charged with emotionalism: about human sexuality, legitimacy of voluntary fertility control, the role and status of women and men, abortion, intergenerational transfer of obligations, ethnic solidarity and the sovereignty of national borders, and the proper roles of the state versus the marketplace. There have been over 200 years of ideological argument over population issues. The Malthusian argument was that large population size did not increase prosperity, and growth should be limited. The Marxist-Leninist position was that contraception was Malthusian, abortion was a woman's right, and population growth was neutral. By late 1970 the Chinese Maoists adopted the moral contraints urged by Malthus. US policies in the 1980s amounted to defunding of population programs and ideological suppression. Seven steps in US policy change are indicated. Centralization of responsibilities for population issues should be determined within government; the Department of State or the National Security Council are likely choices.

Modernization is Associated with Intensive Breastfeeding Patterns in the Bolivian Amazon

PubMed Central

Veile, Amanda; Martin, Melanie; McAllister, Lisa

2014-01-01

For many traditional, non-industrialized populations, intensive and prolonged breastfeeding buffers infant health against poverty, poor sanitation, and limited health care. Due to novel influences on local economies, values, and beliefs, the traditional and largely beneficial breastfeeding patterns of such populations may be changing to the detriment of infant health. To assess if and why such changes are occurring in a traditional breastfeeding population, we document breastfeeding patterns in the Bolivian Tsimane, a forager-horticulturalist population in the early stages of modernization. Three predictions are developed and tested to evaluate the general hypothesis that modernizing influences encourage less intensive breastfeeding in the Tsimane: 1) Tsimane mothers in regions of higher infant mortality will practice more intensive BF; 2) Tsimane mothers who are located closer to a local market town will practice more intensive BF; and 3) Older Tsimane mothers will practice more intensive BF. Predictions were tested using a series of maternal interviews (from 2003-2011, n=215) and observations of mother-infant dyads (from 2002-2007, n=133). Tsimane breastfeeding patterns were generally intensive: 72% of mothers reported initiating BF within a few hours of birth, mean (± SD) age of CF introduction was 4.1±2.0 months, and mean (± SD) weaning age was 19.2±7.3 months. There was, however, intra-population variation in several dimensions of breastfeeding (initiation, frequency, duration, and complementary feeding). Contrary to our predictions, breastfeeding was most intensive in the most modernized Tsimane villages, and maternal age was not a significant predictor of breastfeeding patterns. Regional differences accounted for variation in most dimensions of breastfeeding (initiation, frequency, and complementary feeding). Future research should therefore identify constraints on breastfeeding in the less modernized Tsimane regions, and examine the formation of maternal beliefs regarding infant feeding. PMID:24444850

Uninsurance, underinsurance, and health care utilization in Mexico by US border residents.

PubMed

Su, Dejun; Pratt, William; Stimpson, Jim P; Wong, Rebeca; Pagán, José A

2014-08-01

Using data from the 2008 Cross-Border Utilization of Health Care Survey, we examined the relationship between United States (US) health insurance coverage plans and the use of health care services in Mexico by US residents of the US-Mexico border region. We found immigrants were far more likely to be uninsured than their native-born counterparts (63 vs. 27.8 %). Adults without health insurance coverage were more likely to purchase medications or visit physicians in Mexico compared to insured adults. However, adults with Medicaid coverage were more likely to visit dentists in Mexico compared to uninsured adults. Improving health care access for US residents in the southwestern border region of the country will require initiatives that target not only providing coverage to the large uninsured population but also improving access to health care services for the large underinsured population.

Effects of pH, initial Pb2+ concentration, and polyculture on lead remediation by three duckweed species.

PubMed

Tang, Jie; Chen, Chunxia; Chen, Lei; Daroch, Maurycy; Cui, Yan

2017-10-01

Various geographical duckweed isolates have been developed for phytoremediation of lead. The Pb 2+ removal efficiency of Lemna aequinoctialis, Landoltia punctata, and Spirodela polyrhiza was investigated in monoculture and polyculture at different levels of pH and initial Pb 2+ concentrations. L. aequinoctialis was not sensitive to the tested pH but significantly affected by initial Pb 2+ concentration, whereas synergistic effect of pH and initial Pb 2+ concentration on removal efficiency of L. punctata and S. polyrhiza was found. Although the majority of polycultures showed median removal efficiency as compared to respective monocultures, some of the polycultures achieved higher Pb 2+ removal efficiencies and can promote population to remove Pb 2+ . Besides, the three duckweed strains could be potential candidates for Pb 2+ remediation as compared to previous reports. Conclusively, this study provides useful references for future large-scale duckweed phytoremediation.

In a study of a population cohort in South Africa, HIV patients on antiretrovirals had nearly full recovery of employment.

PubMed

Bor, Jacob; Tanser, Frank; Newell, Marie-Louise; Bärnighausen, Till

2012-07-01

Antiretroviral therapy for HIV may have important economic benefits for patients and their households. We quantified the impact of HIV treatment on employment status among HIV patients in rural South Africa who were enrolled in a public-sector HIV treatment program supported by the President's Emergency Plan for AIDS Relief. We linked clinical data from more than 2,000 patients in the treatment program with ten years of longitudinal socioeconomic data from a complete community-based population cohort of more than 30,000 adults residing in the clinical catchment area. We estimated the employment effects of HIV treatment in fixed-effects regressions. Four years after the initiation of antiretroviral therapy, employment among HIV patients had recovered to about 90 percent of baseline rates observed in the same patients three to five years before they started treatment. Many patients initiated treatment early enough that they were able to avoid any loss of employment due to HIV. These results represent the first estimates of employment recovery among HIV patients in a general population, relative to the employment levels that these patients had prior to job-threatening HIV illness and the decision to seek care. There are large economic benefits to HIV treatment. For some patients, further gains could be obtained from initiating antiretroviral therapy earlier, prior to HIV-related job loss.

Joint Analysis of the Full AzTEC Sub-Millimeter Galaxy Data Set

NASA Astrophysics Data System (ADS)

Wilson, Grant; Ade, P.; Aretxaga, I.; Austermann, J.; Bock, J.; Hughes, D.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P.; Perera, T.; Scott, K.; Yun, M.

2006-12-01

Using the new AzTEC millimeter-wave camera on the James Clerk Maxwell Telescope (JCMT) in winter 2005/06, we conducted several surveys of the submm galaxy (SMG) population. The AzTEC 1.1 millimeter surveys include both blank-fields (no significant bias or foreground contamination) and regions of known over-densities, and are both large (100-1000 sq. arcmin.) and sensitive ( 1 mJy rms). The unique power of the AzTEC data set lies not only in the size and depth of the individual fields, but in the combined surveyed area that totals over 1 square degree. Hundreds of new sub-millimeter sources have been detected. A joint analysis of all AzTEC surveys will provide important new constraints on many characteristics of the SMG population, including number counts, clustering, and variance. In particular, the large area of the full AzTEC data set provides the first significant measurement of the brightest and most rare of the SMG population. Herein we present the initial combined results and explore the future potential of a complete joint analysis of the full AzTEC SMG data set.

Estimating avian population size using Bowden's estimator

USGS Publications Warehouse

Diefenbach, D.R.

2009-01-01

Avian researchers often uniquely mark birds, and multiple estimators could be used to estimate population size using individually identified birds. However, most estimators of population size require that all sightings of marked birds be uniquely identified, and many assume homogeneous detection probabilities. Bowden's estimator can incorporate sightings of marked birds that are not uniquely identified and relax assumptions required of other estimators. I used computer simulation to evaluate the performance of Bowden's estimator for situations likely to be encountered in bird studies. When the assumptions of the estimator were met, abundance and variance estimates and confidence-interval coverage were accurate. However, precision was poor for small population sizes (N < 50) unless a large percentage of the population was marked (>75%) and multiple (≥8) sighting surveys were conducted. If additional birds are marked after sighting surveys begin, it is important to initially mark a large proportion of the population (pm ≥ 0.5 if N ≤ 100 or pm > 0.1 if N ≥ 250) and minimize sightings in which birds are not uniquely identified; otherwise, most population estimates will be overestimated by >10%. Bowden's estimator can be useful for avian studies because birds can be resighted multiple times during a single survey, not all sightings of marked birds have to uniquely identify individuals, detection probabilities among birds can vary, and the complete study area does not have to be surveyed. I provide computer code for use with pilot data to design mark-resight surveys to meet desired precision for abundance estimates.

The population genetics of Quechuas, the largest native South American group: autosomal sequences, SNPs, and microsatellites evidence high level of diversity.

PubMed

Scliar, Marilia O; Soares-Souza, Giordano B; Chevitarese, Juliana; Lemos, Livia; Magalhães, Wagner C S; Fagundes, Nelson J; Bonatto, Sandro L; Yeager, Meredith; Chanock, Stephen J; Tarazona-Santos, Eduardo

2012-03-01

Elucidating the pattern of genetic diversity for non-European populations is necessary to make the benefits of human genetics research available to individuals from these groups. In the era of large human genomic initiatives, Native American populations have been neglected, in particular, the Quechua, the largest South Amerindian group settled along the Andes. We characterized the genetic diversity of a Quechua population in a global setting, using autosomal noncoding sequences (nine unlinked loci for a total of 16 kb), 351 unlinked SNPs and 678 microsatellites and tested predictions of the model of the evolution of Native Americans proposed by (Tarazona-Santos et al.: Am J Hum Genet 68 (2001) 1485-1496). European admixture is <5% and African ancestry is barely detectable in the studied population. The largest genetic distances were between African versus Quechua or Melanesian populations, which is concordant with the African origin of modern humans and the fact that South America was the last part of the world to be peopled. The diversity in the Quechua population is comparable with that of Eurasian populations, and the allele frequency spectrum based on resequencing data does not reflect a reduction in the proportion of rare alleles. Thus, the Quechua population is a large reservoir of common and rare genetic variants of South Amerindians. These results are consistent with and complement our evolutionary model of South Amerindians (Tarazona-Santos et al.: Am J Hum Genet 68 (2001) 1485-1496), proposed based on Y-chromosome data, which predicts high genomic diversity due to the high level of gene flow between Andean populations and their long-term effective population size. Copyright © 2012 Wiley Periodicals, Inc.

Baseline integrated behavioural and biological assessment among most at-risk populations in six high-prevalence states of India: design and implementation challenges.

PubMed

Saidel, Tobi; Adhikary, Rajatashuvra; Mainkar, Mandar; Dale, Jayesh; Loo, Virginia; Rahman, Motiur; Ramesh, Banadakoppa M; Paranjape, Ramesh S

2008-12-01

This paper presents key methodological approaches and challenges in implementing and analysing the first round of the integrated biobehavioural assessment of most-at-risk populations, conducted in conjunction with evaluation of Avahan, the India AIDS initiative. The survey collected data on HIV risk behaviours, sexually transmitted infections and HIV prevalence in 29 districts in six high-prevalence states of India. Groups included female sex workers and clients, men who have sex with men, injecting drug users and truck drivers. Strategies for overcoming some challenges of the large-scale surveys among vulnerable populations, including sampling hidden populations, involvement of the communities targeted by the survey, laboratory and quality control in remote, non-clinic field settings, and data analysis and data use are presented. Satisfying the need for protocols, guidelines and tools that allowed for sufficient standardization, while being tailored enough to fit diverse local situations on such a large scale, with so many implementing partners, emerged as a major management challenge. A major lesson from the first round is the vital importance of investing upfront time in tailoring the sampling methods, data collection instruments, and analysis plan to match measurement objectives. Despite the challenges, the integrated biobehavioural assessment was a huge achievement, and was largely successful in providing previously unavailable information about the HIV situation among populations that are critical to the curtailment of HIV spread in India. Lessons from the first round will be used to evolve the second round into an exercise with increased evaluative capability for Avahan.

Ceftaroline fosamil use in hospitalized patients with acute bacterial skin and skin structure infections: Budget impact analysis from a hospital perspective.

PubMed

Huang, Xingyue; Beresford, Eric; Lodise, Thomas; Friedland, H David

2013-06-15

The budgetary impact of adding ceftaroline fosamil to a hospital formulary for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) was evaluated. A three-year hospital budget impact model was constructed with three initial treatment options for ABSSSIs: ceftaroline fosamil, vancomycin plus aztreonam, and other vancomycin-containing regimens. The target population was hospitalized adult patients with an ABSSSI. Clinical cure rates with initial treatment were assumed to be similar to those from ceftaroline fosamil clinical trials. Patients who did not respond to initial treatment were assumed to be treated successfully with second-line antimicrobial therapy. Length of stay and cost per hospital day (by success or failure with initial treatment) were estimated based on a large database from more than 100 U.S. hospitals. Other model inputs included the annual number of ABSSSI admissions, projected annual case growth rate, proportion of ABSSSI target population receiving vancomycin-containing regimen, expected proportion of ABSSSI target population to be treated with ceftaroline fosamil, drug acquisition cost, cost of antibiotic administration, and cost of vancomycin monitoring. Sensitivity analysis using 95% confidence limits of clinical cure rates was also performed. The estimated total cost of care for treating a patient with an ABSSSI was $395 lower with ceftaroline fosamil ($15,087 versus $15,482) compared with vancomycin plus aztreonam and $72 lower ($15,087 versus $15,159) compared with other vancomycin-containing regimens. Model estimates indicated that adding ceftaroline fosamil to the hospital formulary would not have a negative effect on a hospital's budget for ABSSSI treatment.

Deploying dengue-suppressing Wolbachia : Robust models predict slow but effective spatial spread in Aedes aegypti.

PubMed

Turelli, Michael; Barton, Nicholas H

2017-06-01

A novel strategy for controlling the spread of arboviral diseases such as dengue, Zika and chikungunya is to transform mosquito populations with virus-suppressing Wolbachia. In general, Wolbachia transinfected into mosquitoes induce fitness costs through lower viability or fecundity. These maternally inherited bacteria also produce a frequency-dependent advantage for infected females by inducing cytoplasmic incompatibility (CI), which kills the embryos produced by uninfected females mated to infected males. These competing effects, a frequency-dependent advantage and frequency-independent costs, produce bistable Wolbachia frequency dynamics. Above a threshold frequency, denoted pˆ, CI drives fitness-decreasing Wolbachia transinfections through local populations; but below pˆ, infection frequencies tend to decline to zero. If pˆ is not too high, CI also drives spatial spread once infections become established over sufficiently large areas. We illustrate how simple models provide testable predictions concerning the spatial and temporal dynamics of Wolbachia introductions, focusing on rate of spatial spread, the shape of spreading waves, and the conditions for initiating spread from local introductions. First, we consider the robustness of diffusion-based predictions to incorporating two important features of wMel-Aedes aegypti biology that may be inconsistent with the diffusion approximations, namely fast local dynamics induced by complete CI (i.e., all embryos produced from incompatible crosses die) and long-tailed, non-Gaussian dispersal. With complete CI, our numerical analyses show that long-tailed dispersal changes wave-width predictions only slightly; but it can significantly reduce wave speed relative to the diffusion prediction; it also allows smaller local introductions to initiate spatial spread. Second, we use approximations for pˆ and dispersal distances to predict the outcome of 2013 releases of wMel-infected Aedes aegypti in Cairns, Australia, Third, we describe new data from Ae. aegypti populations near Cairns, Australia that demonstrate long-distance dispersal and provide an approximate lower bound on pˆ for wMel in northeastern Australia. Finally, we apply our analyses to produce operational guidelines for efficient transformation of vector populations over large areas. We demonstrate that even very slow spatial spread, on the order of 10-20 m/month (as predicted), can produce area-wide population transformation within a few years following initial releases covering about 20-30% of the target area. Copyright © 2017 Elsevier Inc. All rights reserved.

The puzzling interpretation of NIR indices: The case of NaI2.21

NASA Astrophysics Data System (ADS)

Röck, B.; Vazdekis, A.; La Barbera, F.; Peletier, R. F.; Knapen, J. H.; Allende-Prieto, C.; Aguado, D. S.

2017-11-01

We present a detailed study of the Na I line strength index centred in the K band at 22 100 Å (NaI2.21 hereafter) relying on different samples of early-type galaxies. Consistent with previous studies, we find that the observed line strength indices cannot be fit by state-of-the-art scaled-solar stellar population models, even using our newly developed models in the near infrared (NIR). The models clearly underestimate the large NaI2.21 values measured for most early-type galaxies. However, we develop an Na-enhanced version of our newly developed models in the NIR, which - together with the effect of a bottom-heavy initial mass function - yield NaI2.21 indices in the range of the observations. Therefore, we suggest a scenario in which the combined effect of [Na/Fe] enhancement and a bottom-heavy initial mass function are mainly responsible for the large NaI2.21 indices observed for most early-type galaxies. To a smaller extent, also [C/Fe] enhancement might contribute to the large observed NaI2.21 values.

Experimental Estimation of Mutation Rates in a Wheat Population With a Gene Genealogy Approach

PubMed Central

Raquin, Anne-Laure; Depaulis, Frantz; Lambert, Amaury; Galic, Nathalie; Brabant, Philippe; Goldringer, Isabelle

2008-01-01

Microsatellite markers are extensively used to evaluate genetic diversity in natural or experimental evolving populations. Their high degree of polymorphism reflects their high mutation rates. Estimates of the mutation rates are therefore necessary when characterizing diversity in populations. As a complement to the classical experimental designs, we propose to use experimental populations, where the initial state is entirely known and some intermediate states have been thoroughly surveyed, thus providing a short timescale estimation together with a large number of cumulated meioses. In this article, we derived four original gene genealogy-based methods to assess mutation rates with limited bias due to relevant model assumptions incorporating the initial state, the number of new alleles, and the genetic effective population size. We studied the evolution of genetic diversity at 21 microsatellite markers, after 15 generations in an experimental wheat population. Compared to the parents, 23 new alleles were found in generation 15 at 9 of the 21 loci studied. We provide evidence that they arose by mutation. Corresponding estimates of the mutation rates ranged from 0 to 4.97 × 10−3 per generation (i.e., year). Sequences of several alleles revealed that length polymorphism was only due to variation in the core of the microsatellite. Among different microsatellite characteristics, both the motif repeat number and an independent estimation of the Nei diversity were correlated with the novel diversity. Despite a reduced genetic effective size, global diversity at microsatellite markers increased in this population, suggesting that microsatellite diversity should be used with caution as an indicator in biodiversity conservation issues. PMID:18689900

Experimental estimation of mutation rates in a wheat population with a gene genealogy approach.

PubMed

Raquin, Anne-Laure; Depaulis, Frantz; Lambert, Amaury; Galic, Nathalie; Brabant, Philippe; Goldringer, Isabelle

2008-08-01

Microsatellite markers are extensively used to evaluate genetic diversity in natural or experimental evolving populations. Their high degree of polymorphism reflects their high mutation rates. Estimates of the mutation rates are therefore necessary when characterizing diversity in populations. As a complement to the classical experimental designs, we propose to use experimental populations, where the initial state is entirely known and some intermediate states have been thoroughly surveyed, thus providing a short timescale estimation together with a large number of cumulated meioses. In this article, we derived four original gene genealogy-based methods to assess mutation rates with limited bias due to relevant model assumptions incorporating the initial state, the number of new alleles, and the genetic effective population size. We studied the evolution of genetic diversity at 21 microsatellite markers, after 15 generations in an experimental wheat population. Compared to the parents, 23 new alleles were found in generation 15 at 9 of the 21 loci studied. We provide evidence that they arose by mutation. Corresponding estimates of the mutation rates ranged from 0 to 4.97 x 10(-3) per generation (i.e., year). Sequences of several alleles revealed that length polymorphism was only due to variation in the core of the microsatellite. Among different microsatellite characteristics, both the motif repeat number and an independent estimation of the Nei diversity were correlated with the novel diversity. Despite a reduced genetic effective size, global diversity at microsatellite markers increased in this population, suggesting that microsatellite diversity should be used with caution as an indicator in biodiversity conservation issues.

Going wild: what a global small-animal tracking system could do for experimental biologists.

PubMed

Wikelski, Martin; Kays, Roland W; Kasdin, N Jeremy; Thorup, Kasper; Smith, James A; Swenson, George W

2007-01-01

Tracking animals over large temporal and spatial scales has revealed invaluable and spectacular biological information, particularly when the paths and fates of individuals can be monitored on a global scale. However, only large animals (greater than approximately 300 g) currently can be followed globally because of power and size constraints on the tracking devices. And yet the vast majority of animals is small. Tracking small animals is important because they are often part of evolutionary and ecological experiments, they provide important ecosystem services and they are of conservation concern or pose harm to human health. Here, we propose a small-animal satellite tracking system that would enable the global monitoring of animals down to the size of the smallest birds, mammals (bats), marine life and eventually large insects. To create the scientific framework necessary for such a global project, we formed the ICARUS initiative (www.IcarusInitiative.org), the International Cooperation for Animal Research Using Space. ICARUS also highlights how small-animal tracking could address some of the ;Grand Challenges in Environmental Sciences' identified by the US National Academy of Sciences, such as the spread of infectious diseases or the relationship between biological diversity and ecosystem functioning. Small-animal tracking would allow the quantitative assessment of dispersal and migration in natural populations and thus help solve enigmas regarding population dynamics, extinctions and invasions. Experimental biologists may find a global small-animal tracking system helpful in testing, validating and expanding laboratory-derived discoveries in wild, natural populations. We suggest that the relatively modest investment into a global small-animal tracking system will pay off by providing unprecedented insights into both basic and applied nature. Tracking small animals over large spatial and temporal scales could prove to be one of the most powerful techniques of the early 21st century, offering potential solutions to a wide range of biological and societal questions that date back two millennia to the Greek philosopher Aristotle's enigma about songbird migration. Several of the more recent Grand Challenges in Environmental Sciences, such as the regulation and functional consequences of biological diversity or the surveillance of the population ecology of zoonotic hosts, pathogens or vectors, could also be addressed by a global small-animal tracking system. Our discussion is intended to contribute to an emerging groundswell of scientific support to make such a new technological system happen.

An ecocultural model predicts Neanderthal extinction through competition with modern humans.

PubMed

Gilpin, William; Feldman, Marcus W; Aoki, Kenichi

2016-02-23

Archaeologists argue that the replacement of Neanderthals by modern humans was driven by interspecific competition due to a difference in culture level. To assess the cogency of this argument, we construct and analyze an interspecific cultural competition model based on the Lotka-Volterra model, which is widely used in ecology, but which incorporates the culture level of a species as a variable interacting with population size. We investigate the conditions under which a difference in culture level between cognitively equivalent species, or alternatively a difference in underlying learning ability, may produce competitive exclusion of a comparatively (although not absolutely) large local Neanderthal population by an initially smaller modern human population. We find, in particular, that this competitive exclusion is more likely to occur when population growth occurs on a shorter timescale than cultural change, or when the competition coefficients of the Lotka-Volterra model depend on the difference in the culture levels of the interacting species.

Deposition and dose from the 18 May 1980 eruption of Mount St. Helens

NASA Technical Reports Server (NTRS)

Peterson, K. R.

1982-01-01

The downwind deposition and radiation doses was calculated for the tropospheric part of the ash cloud from the May 18, 1980 eruption of Mount St. Helens, by using a large cloud diffusion model. The naturally occurring radionnuclides of radium and thorium, whose radon daughters normally seep very slowly from the rocks and soil, were violently released to the atmosphere. The largest dose to an individual from these nuclides is small, but the population dose to those affected by the radioactivity in the ash is about 100 person rem. This population dose from Mount St. Helens is much greater than the annual person rem routinely released by a typical large nuclear power plant. It is estimated that subsequent eruptions of Mount St. Helens have doubled or tripled the person rem calculated from the initial large eruption. The long range global ash deposition of the May 18 eruption is estimated through 1984, by use of a global deposition model. The maximum deposition is nearly 1000 kg square km and occurs in the spring of 1981 over middle latitudes of the Northern Hemisphere.

Investigation of anatomical anomalies in Hanford Site mule deer

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

Tiller, B.L.; Cadwell, L.L.; Poston, T.M.

Rocky Mountain mule deer (Odocoileus hemionus hemionus), common residents of the Hanford Site, are an important part of the shrub-steppe ecosystem as well as being valued for aesthetics and hunting. Because mule deer have been protected from hunting on the Site for 50 years, the herd has developed unique population characteristics, including a large number of old animals and males with either large or atypically developed antlers, in contrast to other herds in the semi-arid regions of the Northwest. Hanford Site mule deer have been studied since 1991 because of the herd`s unique nature and high degree of public interest.more » A special study of the mule deer herd was initiated in 1993 after observations were made of a relatively large number of male deer with atypical, velvet-covered antlers. This report specifically describes our analyses of adult male deer found on the Site with atypical antlers. The report includes estimates of population densities and composition; home ranges, habitat uses, and dietary habits; natural and human-induced causes of mortality; and the herd`s overall health and reproductive status.« less

Relationships between human population density and burned area at continental and global scales.

PubMed

Bistinas, Ioannis; Oom, Duarte; Sá, Ana C L; Harrison, Sandy P; Prentice, I Colin; Pereira, José M C

2013-01-01

We explore the large spatial variation in the relationship between population density and burned area, using continental-scale Geographically Weighted Regression (GWR) based on 13 years of satellite-derived burned area maps from the global fire emissions database (GFED) and the human population density from the gridded population of the world (GPW 2005). Significant relationships are observed over 51.5% of the global land area, and the area affected varies from continent to continent: population density has a significant impact on fire over most of Asia and Africa but is important in explaining fire over < 22% of Europe and Australia. Increasing population density is associated with both increased and decreased in fire. The nature of the relationship depends on land-use: increasing population density is associated with increased burned are in rangelands but with decreased burned area in croplands. Overall, the relationship between population density and burned area is non-monotonic: burned area initially increases with population density and then decreases when population density exceeds a threshold. These thresholds vary regionally. Our study contributes to improved understanding of how human activities relate to burned area, and should contribute to a better estimate of atmospheric emissions from biomass burning.

Relationships between Human Population Density and Burned Area at Continental and Global Scales

PubMed Central

Bistinas, Ioannis; Oom, Duarte; Sá, Ana C. L.; Harrison, Sandy P.; Prentice, I. Colin; Pereira, José M. C.

2013-01-01

We explore the large spatial variation in the relationship between population density and burned area, using continental-scale Geographically Weighted Regression (GWR) based on 13 years of satellite-derived burned area maps from the global fire emissions database (GFED) and the human population density from the gridded population of the world (GPW 2005). Significant relationships are observed over 51.5% of the global land area, and the area affected varies from continent to continent: population density has a significant impact on fire over most of Asia and Africa but is important in explaining fire over < 22% of Europe and Australia. Increasing population density is associated with both increased and decreased in fire. The nature of the relationship depends on land-use: increasing population density is associated with increased burned are in rangelands but with decreased burned area in croplands. Overall, the relationship between population density and burned area is non-monotonic: burned area initially increases with population density and then decreases when population density exceeds a threshold. These thresholds vary regionally. Our study contributes to improved understanding of how human activities relate to burned area, and should contribute to a better estimate of atmospheric emissions from biomass burning. PMID:24358108

Alterations of DNA content in human endometrial stromal cells transfected with a temperature-sensitive SV40: tetraploidization and physiological consequences.

PubMed

Rinehart, C A; Mayben, J P; Butler, T D; Haskill, J S; Kaufman, D G

1992-01-01

The normal genomic stability of human cells is reversed during neoplastic transformation. The SV40 large T antigen alters the DNA content in human endometrial stromal cells in a manner that relates to neoplastic progression. Human endometrial stromal cells were transfected with a plasmid containing the A209 temperature-sensitive mutant of SV40 (tsSV40), which is also defective in the viral origin of replication. Ninety-seven clonal transfectants from seven different primary cell strains were isolated. Initial analysis revealed that 20% of the clonal populations (19/97) had an apparent diploid DNA content, 35% (34/97) had an apparent tetraploid DNA content, and the remainder were mixed populations of diploid and tetraploid cells. No aneuploid populations were observed. Diploid tsSV40 transformed cells always give rise to a population of cells with a tetraploid DNA content when continuously cultured at the permissive temperature. The doubling of DNA content can be vastly accelerated by the sudden reintroduction of large T antigen activity following a shift from non-permissive to permissive temperature. Tetraploid tsSV40 transfected cells have a lower capacity for anchorage-independent growth and earlier entry into 'crisis' than diploid cells. These results indicate that during the pre-crisis, extended lifespan phase of growth, the SV40 large T antigen causes a doubling of DNA content. This apparent doubling of DNA content does not confer growth advantage during the extended lifespan that precedes 'crisis'.

Addressing spiritual leadership: an organizational model.

PubMed

Burkhart, Lisa; Solari-Twadell, P Ann; Haas, Sheila

2008-01-01

The Joint Commission requires health systems to address spiritual care. Research indicates that spirituality is associated with better physical, psychological, and social health and that culturally diverse populations and individuals at end-of-life often request spiritual care. The authors report the results of a consensus conference of 21 executives representing 10 large faith-based health systems who discussed the input, process, and outcomes of a corporate model for spiritual leadership. Specific initiatives are highlighted.

At the Crossroads of Cancer Stem Cells, Radiation Biology, and Radiation Oncology.

PubMed

Gerweck, Leo E; Wakimoto, Hiroaki

2016-03-01

Reports that a small subset of tumor cells initiate and sustain tumor growth, are resistant to radiation and drugs, and bear specific markers have led to an explosion of cancer stem cell research. These reports imply that the evaluation of therapeutic response by changes in tumor volume is misleading, as volume changes reflect the response of the sensitive rather than the resistant tumorigenic cell population. The reports further suggest that the marker-based selection of the tumor cell population will facilitate the development of radiation treatment schedules, sensitizers, and drugs that specifically target the resistant tumorigenic cells that give rise to treatment failure. This review presents evidence that contests the observations that cancer stem cell markers reliably identify the subset of tumor cells that sustain tumor growth and that the marker-identified population is radioresistant relative to the marker-negative cells. Experimental studies show that cells and tumors that survive large radiation doses are not more radioresistant than unirradiated cells and tumors, and also show that the intrinsic radiosensitivity of unsorted colony-forming tumor cells, in combination with the fraction of unsorted tumor cells that are tumor initiating, predicts tumor radiocurability. ©2016 American Association for Cancer Research.

Population and Individual Elephant Response to a Catastrophic Fire in Pilanesberg National Park

PubMed Central

Woolley, Leigh-Ann; Millspaugh, Joshua J.; Woods, Rami J.; Janse van Rensburg, Samantha; Mackey, Robin L.; Page, Bruce; Slotow, Rob

2008-01-01

In predator-free large herbivore populations, where density-dependent feedbacks occur at the limit where forage resources can no longer support the population, environmental catastrophes may play a significant role in population regulation. The potential role of fire as a stochastic mass-mortality event limiting these populations is poorly understood, so too the behavioural and physiological responses of the affected animals to this type of large disturbance event. During September 2005, a wildfire resulted in mortality of 29 (18% population mortality) and injury to 18, African elephants in Pilanesberg National Park, South Africa. We examined movement and herd association patterns of six GPS-collared breeding herds, and evaluated population physiological response through faecal glucocorticoid metabolite (stress) levels. We investigated population size, structure and projected growth rates using a simulation model. After an initial flight response post-fire, severely injured breeding herds reduced daily displacement with increased daily variability, reduced home range size, spent more time in non-tourist areas and associated less with other herds. Uninjured, or less severely injured, breeding herds also shifted into non-tourist areas post-fire, but in contrast, increased displacement rate (both mean and variability), did not adjust home range size and formed larger herds post-fire. Adult cow stress hormone levels increased significantly post-fire, whereas juvenile and adult bull stress levels did not change significantly. Most mortality occurred to the juvenile age class causing a change in post-fire population age structure. Projected population growth rate remained unchanged at 6.5% p.a., and at current fecundity levels, the population would reach its previous level three to four years post-fire. The natural mortality patterns seen in elephant populations during stochastic events, such as droughts, follows that of the classic mortality pattern seen in predator-free large ungulate populations, i.e. mainly involving juveniles. Fire therefore functions in a similar manner to other environmental catastrophes and may be a natural mechanism contributing to population limitation. Welfare concerns of arson fires, burning during “hot-fire” conditions and the conservation implications of fire suppression (i.e. removal of a potential contributing factor to natural population regulation) should be integrated into fire management strategies for conservation areas. PMID:18797503

Skipping Strategy (SS) for Initial Population of Job-Shop Scheduling Problem

NASA Astrophysics Data System (ADS)

Abdolrazzagh-Nezhad, M.; Nababan, E. B.; Sarim, H. M.

2018-03-01

Initial population in job-shop scheduling problem (JSSP) is an essential step to obtain near optimal solution. Techniques used to solve JSSP are computationally demanding. Skipping strategy (SS) is employed to acquire initial population after sequence of job on machine and sequence of operations (expressed in Plates-jobs and mPlates-jobs) are determined. The proposed technique is applied to benchmark datasets and the results are compared to that of other initialization techniques. It is shown that the initial population obtained from the SS approach could generate optimal solution.

Quantification of historical livestock importation into New Zealand 1860-1979.

PubMed

Binney, B M; Biggs, P J; Carter, P E; Holland, B R; Holland, B M; French, N P

2014-11-01

To quantify the numbers of live cattle, sheep and poultry imported into New Zealand and, where possible, their country of origin from 1860 to 1979. Information on the origin and number of live animal importations into New Zealand was collected for cattle, sheep and poultry for the period 1868-1979 from the annual reports compiled by the New Zealand Registrar General's Office, Government Statistician's Office, Census and Statistics Office, Census and Statistics Department, Customs Department and Department of Statistics. Census data from 1851 to 1871 were also used to estimate the livestock population during this period. The number of animals imported and the mean population for each species in a decade were determined, and the major countries of origin were identified. A large number of cattle (53,384) and sheep (604,525) were imported in the 1860s, and then there was a marked reduction in importations. Live poultry were imported in relatively small numbers (20,701) from 1880 to 1939, then 1,564,330 live poultry were imported between 1960 and 1979. Australia was the predominant country of origin for sheep between 1868 and 1959 (51,347/60,918; 84.3%) and of cattle between 1868 and 1979 (10,080/15,157; 66.5%). Only 6,712 (11.0%) sheep and 3,909 (25.8%) cattle were imported from the United Kingdom over the same periods, and even fewer from other countries. The collated data and historical reports show that from 1860 to 1979 Australia has been the main source of livestock introduced into New Zealand. The pattern of importation showed that large numbers of cattle and sheep were initially imported in the 1860s, probably in response to rapid agricultural expansion. Thereafter importations continued at much reduced numbers. In contrast, relatively small numbers of poultry were introduced until the 1960s when large numbers were imported as part of the development of a modern high-production industry. The overall pattern for both cattle and sheep was of a bottleneck event, as initially a relatively limited number of animals arrived from outside populations, followed by population expansion with ongoing but limited immigration (admixture). Investigation into the genetic population structure of New Zealand's cattle and sheep, as well as their host-associated microorganisms, could reflect the impact of these early historical events.

China’s Rapidly Aging Population Creates Policy Challenges In Shaping A Viable Long-Term Care System

PubMed Central

Feng, Zhanlian; Liu, Chang; Guan, Xinping; Mor, Vincent

2013-01-01

In China, formal long-term care services for the large aging population have increased to meet escalating demands as demographic shifts and socioeconomic changes have eroded traditional elder care. We analyze China’s evolving long-term care landscape and trace major government policies and private-sector initiatives shaping it. Although home and community-based services remain spotty, institutional care is booming with little regulatory oversight. Chinese policy makers face mounting challenges overseeing the rapidly growing residential care sector, given the tension arising from policy inducements to further institutional growth, a weak regulatory framework, and the lack of enforcement capacity. We recommend addressing the following pressing policy issues: building a balanced system of services and avoiding an “institutional bias” that promotes rapid growth of elder care institutions over home or community-based care; strengthening regulatory oversight and quality assurance with information systems; and prioritizing education and training initiatives to grow a professionalized long-term care workforce. PMID:23213161

Type 2 vaccine-derived poliovirus from patients with acute flaccid paralysis in china: current immunization strategy effectively prevented its sustained transmission.

PubMed

Zhang, Yong; Yan, Dongmei; Zhu, Shuangli; Wen, Ning; Li, Li; Wang, Haiyan; Liu, Jianfeng; Ye, Xufang; Ding, Zhengrong; Wang, Dongyan; Zhu, Hui; Chen, Li; Hou, Xiaohui; An, Hongqiu; Liang, Xiaofeng; Luo, Huiming; Kew, Olen; Xu, Wenbo

2010-12-15

In China, 5 patients with acute flaccid paralysis (AFP) associated with type 2 vaccine-derived poliovirus (VDPV) were identified by an AFP surveillance system from 1996 through 2009. A maximum-likelihood tree shows that all 5 Chinese VDPVs were independent. These 5 VDPVs were 100-216 d old according to the number of synonymous substitutions per synonymous site and 176-292 d old according to the number of substitutions per site. This result indicates limited virus replication since the administration of the initiating oral polio vaccine (OPV) dose, which is consistent with the rapid evolution rate of poliovirus genomes. The above-mentioned VDPVs have important implications in the global polio eradication initiative. Localized, limited, and transient circulation may be typical of OPVs; hence, independent VDPVs could be found because of the large population and excellent surveillance system, which permitted early detection and response, but sustained transmission was limited because of high population immunity.

Alternatives to national average income data as eligibility criteria for international subsidies: a social justice perspective.

PubMed

Shebaya, Sirine; Sutherland, Andrea; Levine, Orin; Faden, Ruth

2010-12-01

Current strategies to address global inequities in access to life-saving vaccines use averaged national income data to determine eligibility. While largely successful in the lowest income countries, we argue that this approach could lead to significant inefficiencies from the standpoint of justice if applied to middle-income countries, where income inequalities are large and lead to national averages that obscure truly needy populations. Instead, we suggest alternative indicators more sensitive to social justice concerns that merit consideration by policy-makers developing new initiatives to redress health inequities in middle-income countries. © 2009 Blackwell Publishing Ltd.

A Gompertz population model with Allee effect and fuzzy initial values

NASA Astrophysics Data System (ADS)

Amarti, Zenia; Nurkholipah, Nenden Siti; Anggriani, Nursanti; Supriatna, Asep K.

2018-03-01

Growth and population dynamics models are important tools used in preparing a good management for society to predict the future of population or species. This has been done by various known methods, one among them is by developing a mathematical model that describes population growth. Models are usually formed into differential equations or systems of differential equations, depending on the complexity of the underlying properties of the population. One example of biological complexity is Allee effect. It is a phenomenon showing a high correlation between very small population size and the mean individual fitness of the population. In this paper the population growth model used is the Gompertz equation model by considering the Allee effect on the population. We explore the properties of the solution to the model numerically using the Runge-Kutta method. Further exploration is done via fuzzy theoretical approach to accommodate uncertainty of the initial values of the model. It is known that an initial value greater than the Allee threshold will cause the solution rises towards carrying capacity asymptotically. However, an initial value smaller than the Allee threshold will cause the solution decreases towards zero asymptotically, which means the population is eventually extinct. Numerical solutions show that modeling uncertain initial value of the critical point A (the Allee threshold) with a crisp initial value could cause the extinction of population of a certain possibilistic degree, depending on the predetermined membership function of the initial value.

Community-based efforts to prevent obesity: Australia-wide survey of projects.

PubMed

Nichols, Melanie S; Reynolds, Rebecca C; Waters, Elizabeth; Gill, Timothy; King, Lesley; Swinburn, Boyd A; Allender, Steven

2013-08-01

Community-based programs that affect healthy environments and policies have emerged as an effective response to high obesity levels in populations. Apart from limited individual reports, little is currently known about these programs, limiting the potential to provide effective support, to promote effective practice, prevent adverse outcomes and disseminate intervention results and experience. The aim of the present study was to identify the size and reach of current community-based obesity prevention projects in Australia and to examine their characteristics, program features (e.g. intervention setting), capacity and approach to obesity prevention. Detailed survey completed by representatives from community-based obesity prevention initiatives in Australia. There was wide variation in funding, capacity and approach to obesity prevention among the 78 participating projects. Median annual funding was Au$94900 (range Au$2500-$4.46 million). The most common intervention settings were schools (39%). Forty per cent of programs focused on a population group of ≥50000 people. A large proportion of respondents felt that they did not have sufficient resources or staff training to achieve project objectives. Community-based projects currently represent a very large investment by both government and non-government sectors for the prevention of obesity. Existing projects are diverse in size and scope, and reach large segments of the population. Further work is needed to identify the full extent of existing community actions and to monitor their reach and future 'scale up' to ensure that future activities aim for effective integration into systems, policies and environments. SO WHAT? Community-based programs make a substantial contribution to the prevention of obesity and promotion of healthy lifestyles in Australia. A risk of the current intervention landscape is that effective approaches may go unrecognised due to lack of effective evaluations or limitations in program design, duration or size. Policy makers and researchers must recognise the potential contribution of these initiatives, to both public health and knowledge generation, and provide support for strong evaluation and sustainable intervention designs.

Major QTLs for critical photoperiod and vernalization underlie extensive variation in flowering in the Mimulus guttatus species complex.

PubMed

Friedman, Jannice; Willis, John H

2013-07-01

Species with extensive ranges experience highly variable environments with respect to temperature, light and soil moisture. Synchronizing the transition from vegetative to floral growth is important to employ favorable conditions for reproduction. Optimal timing of this transition might be different for semelparous annual plants and iteroparous perennial plants. We studied variation in the critical photoperiod necessary for floral induction and the requirement for a period of cold-chilling (vernalization) in 46 populations of annuals and perennials in the Mimulus guttatus species complex. We then examined critical photoperiod and vernalization QTLs in growth chambers using F(2) progeny from annual and perennial parents that differed in their requirements for flowering. We identify extensive variation in critical photoperiod, with most annual populations requiring substantially shorter day lengths to initiate flowering than perennial populations. We discover a novel type of vernalization requirement in perennial populations that is contingent on plants experiencing short days first. QTL analyses identify two large-effect QTLs which influence critical photoperiod. In two separate vernalization experiments we discover each set of crosses contain different large-effect QTLs for vernalization. Mimulus guttatus harbors extensive variation in critical photoperiod and vernalization that may be a consequence of local adaptation. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Legacy of mutiny on the Bounty: founder effect and admixture on Norfolk Island

PubMed Central

Macgregor, Stuart; Bellis, Claire; Lea, Rod A; Cox, Hannah; Dyer, Tom; Blangero, John; Visscher, Peter M; Griffiths, Lyn R

2010-01-01

The population of Norfolk Island, located off the eastern coast of Australia, possesses an unusual and fascinating history. Most present-day islanders are related to a small number of the ‘Bounty' mutineer founders. These founders consisted of Caucasian males and Polynesian females and led to an admixed present-day population. By examining a single large pedigree of 5742 individuals, spanning >200 years, we analyzed the influence of admixture and founder effect on various cardiovascular disease (CVD)-related traits. On account of the relative isolation of the population, on average one-third of the genomes of present-day islanders (single large pedigree individuals) is derived from 17 initial founders. The proportion of Polynesian ancestry in the present-day individuals was found to significantly influence total triglycerides, body mass index, systolic blood pressure and diastolic blood pressure. For various cholesterol traits, the influence of ancestry was less marked but overall the direction of effect for all CVD-related traits was consistent with Polynesian ancestry conferring greater CVD risk. Marker-derived homozygosity was computed and agreed with measures of inbreeding derived from pedigree information. Founder effect (inbreeding and marker-derived homozygosity) significantly influenced height. In conclusion, both founder effect and extreme admixture have substantially influenced the genetic architecture of a variety of CVD-related traits in this population. PMID:19584896

Society of Behavioral Medicine (SBM) position statement: SBM supports the National Colorectal Cancer Roundtable's (NCCRT) call to action to reach 80 % colorectal cancer screening rates by 2018.

PubMed

Becker, Elizabeth A; Buscemi, Joanna; Fitzgibbon, Marian L; Watson, Karriem; Matthews, Kameron L; Winn, Robert A

2016-06-01

The Society of Behavioral Medicine (SBM) urges stakeholders to support the National Colorectal Cancer Roundtable's (NCCRT) initiative 80 % by 2018. Colorectal cancer (CRC) is largely preventable with early detection of pre-cancerous polyps but CRC screening is underutilized, especially among the underserved. In response to low screening rates, this initiative sets an important goal of a population screening rate of 80 % in adults ages 50 and older by the year 2018. It is estimated that this screening rate could prevent more than 20,000 CRC deaths per year within 15 years. The initiative takes a multilevel approach to improving screening rates and includes recommendations for clinicians, health care organizations, insurers, policymakers, and researchers.

Do Massive Galaxies at z~6 Present a Challenge for Hierarchical Merging?

NASA Astrophysics Data System (ADS)

Steinhardt, Charles L.; Capak, Peter L.; Masters, Daniel; Speagle, Josh S.; Splash

2015-01-01

The Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) recently released an initial view of the massive star-forming galaxy population at 4 < z < 6 over 1.8 square degrees. SPLASH found approximately 100 galaxy candidates with best-fit stellar masses over 10^11 solar. If even 10% of these are truly this massive and at such a high redshift, the corresponding number density would be inconsistent with the halo mass functions produced at these redshifts by numerical simulations. We will discuss these candidates, prospects for followup observations, and the potential implications for our understanding of the initial formation and early evolution of galaxies in the high-redshift universe.

Distinctive properties of metastasis-initiating cells

PubMed Central

Celià-Terrassa, Toni; Kang, Yibin

2016-01-01

Primary tumors are known to constantly shed a large number of cancer cells into systemic dissemination, yet only a tiny fraction of these cells is capable of forming overt metastases. The tremendous rate of attrition during the process of metastasis implicates the existence of a rare and unique population of metastasis-initiating cells (MICs). MICs possess advantageous traits that may originate in the primary tumor but continue to evolve during dissemination and colonization, including cellular plasticity, metabolic reprogramming, the ability to enter and exit dormancy, resistance to apoptosis, immune evasion, and co-option of other tumor and stromal cells. Better understanding of the molecular and cellular hallmarks of MICs will facilitate the development and deployment of novel therapeutic strategies. PMID:27083997

Fluid Overload and Fluid Removal in Pediatric Patients on Extracorporeal Membrane Oxygenation Requiring Continuous Renal Replacement Therapy

PubMed Central

Selewski, David T; Cornell, Timothy T; Blatt, Neal B; Han, Yong Y; Mottes, Theresa; Kommareddi, Mallika; Gaies, Michael G; Annich, Gail M; Kershaw, David B; Shanley, Thomas P; Heung, Michael

2012-01-01

Objective In pediatric patients fluid overload (FO) at continuous renal replacement (CRRT) initiation is associated with increased mortality. The aim of this study was to characterize the association between fluid overload at CRRT initiation, fluid removal during CRRT, the kinetics of fluid removal and mortality in a large pediatric population receiving CRRT while on extracorporeal membrane oxygenation (ECMO). Design Retrospective chart review. Setting Tertiary children’s hospital Patients ECMO patients requiring CRRT from July 2006 to September 2010 Interventions None Measurements and Main Results Overall ICU survival was 34% for 53 patients that were initiated on CRRT while on ECMO during the study period. Median FO at CRRT initiation was significantly lower in survivors compared to non-survivors (24.5 vs. 38%, p=0.006). Median FO at CRRT discontinuation was significantly lower in survivors compared to non-survivors (7.1 vs. 17.5%, p=0.035). After adjusting for percent FO at CRRT initiation, age and severity of illness, the change in FO at CRRT discontinuation was not significantly associated with mortality (p=0.212). Models investigating the rates of fluid removal in different periods, age, severity of illness and fluid overload at CRRT initiation found that fluid overload at CRRT initiation was the most consistent predictor of survival. Conclusions Our data demonstrates an association between FO at CRRT initiation and mortality in pediatric patients receiving ECMO. The degree of FO at CRRT discontinuation is also associated with mortality, but appears to reflect the effect of FO at initiation. Furthermore, correction of FO to ≤ 10% was not associated with improved survival. These results suggest that intervening prior to the development of significant FO may be more clinically effective than attempting fluid removal after significant fluid overload has developed. Our findings suggest a role for earlier initiation of CRRT in this population, and warrant further clinical studies. PMID:22743776

The estimation of growth dynamics for Pomacea maculata from hatchling to adult

USGS Publications Warehouse

Sutton, Karyn L.; Zhao, Lihong; Carter, Jacoby

2017-01-01

Pomacea maculata is a relatively new invasive species to the Gulf Coast region and potentially threatens local agriculture (rice) and ecosystems (aquatic vegetation). The population dynamics of P. maculata have largely been unquantified, and therefore, scientists and field-workers are ill-equipped to accurately project population sizes and the resulting impact of this species. We studied the growth of P. maculata ranging in weights from 6 to 105 g, identifying the sex of the animals when possible. Our studied population had a 4:9 male:female sex ratio. We present the findings from initial analysis of the individual growth data of males and females, from which it was apparent that females were generally larger than males and that small snails grew faster than larger snails. Since efforts to characterize the male and female growth rates from individual data do not yield statistically supported estimates, we present the estimation of several parameterized growth rate functions within a population-level mathematical model. We provide a comparison of the results using these various growth functions and discuss which best characterizes the dynamics of our observed population. We conclude that both males and females exhibit biphasic growth rates, and thus, their growth is size-dependent. Further, our results suggest that there are notable differences between males and females that are important to take into consideration in order to accurately model this species' population dynamics. Lastly, we include preliminary analyses of ongoing experiments to provide initial estimates of growth in the earliest life stages (hatchling to ≈6 g).

Whole-Genome Sequencing and Variant Analysis of Human Papillomavirus 16 Infections.

PubMed

van der Weele, Pascal; Meijer, Chris J L M; King, Audrey J

2017-10-01

Human papillomavirus (HPV) is a strongly conserved DNA virus, high-risk types of which can cause cervical cancer in persistent infections. The most common type found in HPV-attributable cancer is HPV16, which can be subdivided into four lineages (A to D) with different carcinogenic properties. Studies have shown HPV16 sequence diversity in different geographical areas, but only limited information is available regarding HPV16 diversity within a population, especially at the whole-genome level. We analyzed HPV16 major variant diversity and conservation in persistent infections and performed a single nucleotide polymorphism (SNP) comparison between persistent and clearing infections. Materials were obtained in the Netherlands from a cohort study with longitudinal follow-up for up to 3 years. Our analysis shows a remarkably large variant diversity in the population. Whole-genome sequences were obtained for 57 persistent and 59 clearing HPV16 infections, resulting in 109 unique variants. Interestingly, persistent infections were completely conserved through time. One reinfection event was identified where the initial and follow-up samples clustered differently. Non-A1/A2 variants seemed to clear preferentially ( P = 0.02). Our analysis shows that population-wide HPV16 sequence diversity is very large. In persistent infections, the HPV16 sequence was fully conserved. Sequencing can identify HPV16 reinfections, although occurrence is rare. SNP comparison identified no strongly acting effect of the viral genome affecting HPV16 infection clearance or persistence in up to 3 years of follow-up. These findings suggest the progression of an early HPV16 infection could be host related. IMPORTANCE Human papillomavirus 16 (HPV16) is the predominant type found in cervical cancer. Progression of initial infection to cervical cancer has been linked to sequence properties; however, knowledge of variants circulating in European populations, especially with longitudinal follow-up, is limited. By sequencing a number of infections with known follow-up for up to 3 years, we gained initial insights into the genetic diversity of HPV16 and the effects of the viral genome on the persistence of infections. A SNP comparison between sequences obtained from clearing and persistent infections did not identify strongly acting DNA variations responsible for these infection outcomes. In addition, we identified an HPV16 reinfection event where sequencing of initial and follow-up samples showed different HPV16 variants. Based on conventional genotyping, this infection would incorrectly be considered a persistent HPV16 infection. In the context of vaccine efficacy and monitoring studies, such infections could potentially cause reduced reported efficacy or efficiency. Copyright © 2017 van der Weele et al.

Punctuated equilibrium and shock waves in molecular models of biological evolution.

PubMed

Saakian, David B; Ghazaryan, Makar H; Hu, Chin-Kun

2014-08-01

We consider the dynamics in infinite population evolution models with a general symmetric fitness landscape. We find shock waves, i.e., discontinuous transitions in the mean fitness, in evolution dynamics even with smooth fitness landscapes, which means that the search for the optimal evolution trajectory is more complicated. These shock waves appear in the case of positive epistasis and can be used to represent punctuated equilibria in biological evolution during long geological time scales. We find exact analytical solutions for discontinuous dynamics at the large-genome-length limit and derive optimal mutation rates for a fixed fitness landscape to send the population from the initial configuration to some final configuration in the fastest way.

Immigrant workers in the United States: recent trends, vulnerable populations, and challenges for occupational health.

PubMed

McCauley, Linda A

2005-07-01

Immigrant workers are a rapidly growing segment of the U.S. work force, and these increasing numbers have resulted in a different ethnic mix in the work force than in previous decades. Immigrant workers are not a homogenous group, but are over-represented in low-paying occupations. Their diversity and vulnerability present distinct challenges for occupational health nurses. High-risk occupations in which a large proportion of immigrant workers are hired include agriculture, sweatshops, day laborers, and construction. Initiatives needed to improve the working conditions of this vulnerable population include improved surveillance and research, culturally competent care providers, improved health care access, advocacy, and changes in immigration and health policy.

The current state of funded NIH grants in implementation science in genomic medicine: a portfolio analysis.

PubMed

Roberts, Megan C; Clyne, Mindy; Kennedy, Amy E; Chambers, David A; Khoury, Muin J

2017-10-26

PurposeImplementation science offers methods to evaluate the translation of genomic medicine research into practice. The extent to which the National Institutes of Health (NIH) human genomics grant portfolio includes implementation science is unknown. This brief report's objective is to describe recently funded implementation science studies in genomic medicine in the NIH grant portfolio, and identify remaining gaps.MethodsWe identified investigator-initiated NIH research grants on implementation science in genomic medicine (funding initiated 2012-2016). A codebook was adapted from the literature, three authors coded grants, and descriptive statistics were calculated for each code.ResultsForty-two grants fit the inclusion criteria (~1.75% of investigator-initiated genomics grants). The majority of included grants proposed qualitative and/or quantitative methods with cross-sectional study designs, and described clinical settings and primarily white, non-Hispanic study populations. Most grants were in oncology and examined genetic testing for risk assessment. Finally, grants lacked the use of implementation science frameworks, and most examined uptake of genomic medicine and/or assessed patient-centeredness.ConclusionWe identified large gaps in implementation science studies in genomic medicine in the funded NIH portfolio over the past 5 years. To move the genomics field forward, investigator-initiated research grants should employ rigorous implementation science methods within diverse settings and populations.Genetics in Medicine advance online publication, 26 October 2017; doi:10.1038/gim.2017.180.

Social equity and environmental risk

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

Zimmerman, R.

1993-12-01

Social equity has become an important concern of the environmental movement over the past decade. The equity issue is analyzed here for practically all of the inactive hazardous waste disposal sites on the National Priorities List (NPL) regulated under the Comprehensive Response Compensation and Liability Act and its 1986 Superfund Amendments and Reauthorization Act (CERCLA/SARA). Two dimensions of equity are emphasized, namely, site location relative to the location of minority population and the distribution of cleanup plans or Records of Decision (ROD) across communities with NPL sites that have different socioeconomic characteristics. With respect to site location, the percentage ofmore » Blacks and Hispanics aggregated at the Census Place or MCD level in communities with NPL sites was greater than is typical nationwide (largely attributable to the concentration of minority populations in a few large urban areas with NPL sites). The percentage of the population below the poverty line in communities with NPL sites largely matched that of the nation as a whole. With respect to site cleanup, communities with relatively higher percentages of racial minority population have fewer cleanup plans than other communities with NPL site. Whether a ROD exists is influenced by when the site was designated for the NPL: sites designated earlier are more likely to have RODs and less likely to have high proportions of racial minority populations than sites designated later. This implies that initially the designation process may have resulted in NPL sites being located disproportionately in minority areas, but this pattern seems to be reversing itself in more recently designated sites. Racial and ethnic disproportionalities with respect to inactive hazardous waste site location seem to be concentrated in a relatively few areas. 35 refs., 12 tabs.« less

A population study of Alzheimer's disease: findings from the Cache County Study on Memory, Health, and Aging.

PubMed

Tschanz, Joann T; Treiber, Katherine; Norton, Maria C; Welsh-Bohmer, Kathleen A; Toone, Leslie; Zandi, Peter P; Szekely, Christine A; Lyketsos, Constantine; Breitner, John C S

2005-01-01

There are several population-based studies of aging, memory, and dementia being conducted worldwide. Of these, the Cache County Study on Memory, Health and Aging is noteworthy for its large number of "oldest-old" members. This study, which has been following an initial cohort of 5,092 seniors since 1995, has reported among its major findings the role of the Apolipoprotein E gene on modifying the risk for Alzheimer's disease (AD) in males and females and identifying pharmacologic compounds that may act to reduce AD risk. This article summarizes the major findings of the Cache County study to date, describes ongoing investigations, and reports preliminary analyses on the outcome of the oldest-old in this population, the subgroup of participants who were over age 84 at the study's inception.

Noise-induced bistability in the quasi-neutral coexistence of viral RNAs under different replication modes.

PubMed

Sardanyés, Josep; Arderiu, Andreu; Elena, Santiago F; Alarcón, Tomás

2018-05-01

Evolutionary and dynamical investigations into real viral populations indicate that RNA replication can range between the two extremes represented by so-called 'stamping machine replication' (SMR) and 'geometric replication' (GR). The impact of asymmetries in replication for single-stranded (+) sense RNA viruses has been mainly studied with deterministic models. However, viral replication should be better described by including stochasticity, as the cell infection process is typically initiated with a very small number of RNA macromolecules, and thus largely influenced by intrinsic noise. Under appropriate conditions, deterministic theoretical descriptions of viral RNA replication predict a quasi-neutral coexistence scenario, with a line of fixed points involving different strands' equilibrium ratios depending on the initial conditions. Recent research into the quasi-neutral coexistence in two competing populations reveals that stochastic fluctuations fundamentally alter the mean-field scenario, and one of the two species outcompetes the other. In this article, we study this phenomenon for viral RNA replication modes by means of stochastic simulations and a diffusion approximation. Our results reveal that noise has a strong impact on the amplification of viral RNAs, also causing the emergence of noise-induced bistability. We provide analytical criteria for the dominance of (+) sense strands depending on the initial populations on the line of equilibria, which are in agreement with direct stochastic simulation results. The biological implications of this noise-driven mechanism are discussed within the framework of the evolutionary dynamics of RNA viruses with different modes of replication. © 2018 The Author(s).

SPSmart: adapting population based SNP genotype databases for fast and comprehensive web access.

PubMed

Amigo, Jorge; Salas, Antonio; Phillips, Christopher; Carracedo, Angel

2008-10-10

In the last five years large online resources of human variability have appeared, notably HapMap, Perlegen and the CEPH foundation. These databases of genotypes with population information act as catalogues of human diversity, and are widely used as reference sources for population genetics studies. Although many useful conclusions may be extracted by querying databases individually, the lack of flexibility for combining data from within and between each database does not allow the calculation of key population variability statistics. We have developed a novel tool for accessing and combining large-scale genomic databases of single nucleotide polymorphisms (SNPs) in widespread use in human population genetics: SPSmart (SNPs for Population Studies). A fast pipeline creates and maintains a data mart from the most commonly accessed databases of genotypes containing population information: data is mined, summarized into the standard statistical reference indices, and stored into a relational database that currently handles as many as 4 x 10(9) genotypes and that can be easily extended to new database initiatives. We have also built a web interface to the data mart that allows the browsing of underlying data indexed by population and the combining of populations, allowing intuitive and straightforward comparison of population groups. All the information served is optimized for web display, and most of the computations are already pre-processed in the data mart to speed up the data browsing and any computational treatment requested. In practice, SPSmart allows populations to be combined into user-defined groups, while multiple databases can be accessed and compared in a few simple steps from a single query. It performs the queries rapidly and gives straightforward graphical summaries of SNP population variability through visual inspection of allele frequencies outlined in standard pie-chart format. In addition, full numerical description of the data is output in statistical results panels that include common population genetics metrics such as heterozygosity, Fst and In.

RAPID EVOLUTION CAUSED BY POLLINATOR LOSS IN MIMULUS GUTTATUS

PubMed Central

Bodbyl Roels, Sarah A.; Kelly, John K.

2018-01-01

Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant–pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther–stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait “selfing syndrome” observed throughout angiosperms. PMID:21884055

The Cultural Evolution of Human Communication Systems in Different Sized Populations: Usability Trumps Learnability

PubMed Central

Fay, Nicolas; Ellison, T. Mark

2013-01-01

This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both), and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity), but harder to learn (identification accuracy) for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs) is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability. PMID:23967243

The cultural evolution of human communication systems in different sized populations: usability trumps learnability.

PubMed

Fay, Nicolas; Ellison, T Mark

2013-01-01

This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both), and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity), but harder to learn (identification accuracy) for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs) is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability.

Rapid evolution caused by pollinator loss in Mimulus guttatus.

PubMed

Roels, Sarah A Bodbyl; Kelly, John K

2011-09-01

Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant-pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther-stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait "selfing syndrome" observed throughout angiosperms. © 2011 The Author(s).

Ongoing Use of Data and Specimens from NCI Sponsored Cancer Prevention Clinical Trials in the Community Clinical Oncology Program

PubMed Central

Minasian, Lori; Tangen, Catherine M.; Wickerham, D. Lawrence

2015-01-01

Large cancer prevention trials provide opportunities to collect a wide array of data and biospecimens at study entry and longitudinally, for a healthy, aging population without cancer. This provides an opportunity to use pre-diagnostic data and specimens to evaluate hypotheses about the initial development of cancer. This paper reports on strides made by, and future possibilities for, the use of accessible biorepositories developed from precisely annotated samples obtained through large-scale National Cancer Institute (NCI)-sponsored cancer prevention clinical trials conducted by the NCI Cooperative Groups. These large cancer prevention studies, which have enrolled over 80,000 volunteers, continue to contribute to our understanding of cancer development more than 10 years after they were closed. PMID:26433556

Reciprocal transplants support a plasticity-first scenario during colonisation of a large hyposaline basin by a marine macro alga.

PubMed

Johansson, Daniel; Pereyra, Ricardo T; Rafajlović, Marina; Johannesson, Kerstin

2017-04-05

Establishing populations in ecologically marginal habitats may require substantial phenotypic changes that come about through phenotypic plasticity, local adaptation, or both. West-Eberhard's "plasticity-first" model suggests that plasticity allows for rapid colonisation of a new environment, followed by directional selection that develops local adaptation. Two predictions from this model are that (i) individuals of the original population have high enough plasticity to survive and reproduce in the marginal environment, and (ii) individuals of the marginal population show evidence of local adaptation. Individuals of the macroalga Fucus vesiculosus from the North Sea colonised the hyposaline (≥2-3‰) Baltic Sea less than 8000 years ago. The colonisation involved a switch from fully sexual to facultative asexual recruitment with release of adventitious branches that grow rhizoids and attach to the substratum. To test the predictions from the plasticity-first model we reciprocally transplanted F. vesiculosus from the original population (ambient salinity 24‰) and from the marginal population inside the Baltic Sea (ambient salinity 4‰). We also transplanted individuals of the Baltic endemic sister species F. radicans from 4 to 24‰. We assessed the degree of plasticity and local adaptation in growth and reproductive traits after 6 months by comparing the performance of individuals in 4 and 24‰. Branches of all individuals survived the 6 months period in both salinities, but grew better in their native salinity. Baltic Sea individuals more frequently developed asexual traits while North Sea individuals initiated formation of receptacles for sexual reproduction. Marine individuals of F. vesiculosus are highly plastic with respect to salinity and North Sea populations can survive the extreme hyposaline conditions of the Baltic Sea without selective mortality. Plasticity alone would thus allow for an initial establishment of this species inside the postglacial Baltic Sea at salinities where reproduction remains functional. Since establishment, the Baltic Sea populations have evolved adaptations to extreme hyposaline waters and have in addition evolved asexual recruitment that, however, tends to impede local adaptation. Overall, our results support the "plasticity-first" model for the initial colonisation of the Baltic Sea by Fucus vesiculosus.

Model of unplanned smoking initiation of children and adolescents: an integrated stage model of smoking behavior.

PubMed

Kremers, S P J; Mudde, A N; De Vries, H

2004-05-01

Two lines of psychological research have attempted to spell out the stages of adolescent smoking initiation. The first has focused on behavioral stages of smoking initiation, while the second line emphasized motivational stages. A large international sample of European adolescents (N = 10,170, mean age = 13.3 years) was followed longitudinally. Self-reported motivational and behavioral stages of smoking initiation were integrated, leading to the development of the Model of Unplanned Smoking Initiation of Children and Adolescents (MUSICA). The MUSICA postulates that youngsters experiment with smoking while they are in an unmotivated state as regards their plans for smoking regularly in the future. More than 95% of the total population resided in one of the seven stages distinguished by MUSICA. The probability of starting to smoke regularly during the 12 months follow-up period increased with advanced stage assignment at baseline. Unique social cognitive predictors of stage progression from the various stages were identified, but effect sizes of predictors of transitions were small. The integration of motivational and behavioral dimensions improves our understanding of the process of smoking initiation. In contrast to current theories of smoking initiation, adolescent uptake of smoking behavior was found to be an unplanned action.

Global population collapse in a superabundant migratory bird and illegal trapping in China.

PubMed

Kamp, Johannes; Oppel, Steffen; Ananin, Alexandr A; Durnev, Yurii A; Gashev, Sergey N; Hölzel, Norbert; Mishchenko, Alexandr L; Pessa, Jorma; Smirenski, Sergey M; Strelnikov, Evgenii G; Timonen, Sami; Wolanska, Kolja; Chan, Simba

2015-12-01

Persecution and overexploitation by humans are major causes of species extinctions. Rare species, often confined to small geographic ranges, are usually at highest risk, whereas extinctions of superabundant species with very large ranges are rare. The Yellow-breasted Bunting (Emberiza aureola) used to be one of the most abundant songbirds of the Palearctic, with a very large breeding range stretching from Scandinavia to the Russian Far East. Anecdotal information about rapid population declines across the range caused concern about unsustainable trapping along the species' migration routes. We conducted a literature review and used long-term monitoring data from across the species' range to model population trend and geographical patterns of extinction. The population declined by 84.3-94.7% between 1980 and 2013, and the species' range contracted by 5000 km. Quantitative evidence from police raids suggested rampant illegal trapping of the species along its East Asian flyway in China. A population model simulating an initial harvest level of 2% of the population, and an annual increase of 0.2% during the monitoring period produced a population trajectory that matched the observed decline. We suggest that trapping strongly contributed to the decline because the consumption of Yellow-breasted Bunting and other songbirds has increased as a result of economic growth and prosperity in East Asia. The magnitude and speed of the decline is unprecedented among birds with a comparable range size, with the exception of the Passenger Pigeon (Ectopistes migratorius), which went extinct in 1914 due to industrial-scale hunting. Our results demonstrate the urgent need for an improved monitoring of common and widespread species' populations, and consumption levels throughout East Asia. © 2015 Society for Conservation Biology.

Cathepsin L and cystatin B gene expression discriminates immune cœlomic cells in the leech Theromyzon tessulatum

PubMed Central

Lefebvre, Christophe; Vandenbulcke, Franck; Bocquet, Béatrice; Tasiemski, Aurélie; Desmons, Annie; Verstraete, Mathilde; Salzet, Michel; Cocquerelle, Claude

2009-01-01

Previous studies evidenced that cystatin B-like gene is specifically expressed and induced in large circulating cœlomic cells following bacterial challenge in the leech Theromyzon tessulatum. In order to understand the role of that cysteine proteinase inhibitor during immune response, we investigated the existence of members of cathepsin family. We cloned a cathepsin L-like gene and studied its tissue distribution. Immunohistochemical studies using anti-cathepsin L and anti-cystatin B antibodies and ultrastructural results demonstrated the presence of three distinct cœlomic cell populations, (1) the chloragocytes which were initially defined as large cœlomocytes, (2) the granular amœbocytes, and (3) small cœlomic cells. Among those cells, while chloragocytes contain cystatin B and cathepsin L, granular amœbocytes do only contain cathepsin L and third cell population contains neither cathepsin nor inhibitor. Finally, results evidenced that cathepsin L immunopositive granular amœbocytes are chemoattracted to the site of injury and phagocyte bacteria. PMID:18177937

Population receptivity to tobacco advertising/promotions and exposure to anti-tobacco media: effect of Master Settlement Agreement in California: 1992-2002.

PubMed

Gilpin, Elizabeth A; Distefan, Janet M; Pierce, John P

2004-07-01

Tobacco marketing contributes to adolescent smoking initiation, and the Master Settlement Agreement (MSA), therefore, included relevant restrictions. We analyzed data from large population surveys of Californians, conducted in 1992 (11,905 adults, ages 18 years and older), 1993 (5,531 adolescents, ages 12 to 17 years), and 1996 (6,252 adolescents, 18,616 adults) before the MSA, and in 1999 (6,090 adolescents, 14,729 adults) and 2002 (5,857 adolescents, 20,525 adults) following its implementation. Camel lost favorite-advertisement popularity after 1996, and between 1999 and 2002, there were large increases in the percentages declining to name a favorite advertisement. Ownership of tobacco promotional items declined from its peak in 1996. Furthermore, in 2002, close to 90% of adolescents and young adults reported seeing anti-tobacco messages on television in the past month, significantly higher than 1996. These trends indicate less receptivity to tobacco advertising and promotions following the MSA but leave room for additional restrictions to further reduce receptivity.

An initiator codon mutation in SDE2 causes recessive embryonic lethality in Holstein cattle.

PubMed

Fritz, Sébastien; Hoze, Chris; Rebours, Emmanuelle; Barbat, Anne; Bizard, Méline; Chamberlain, Amanda; Escouflaire, Clémentine; Vander Jagt, Christy; Boussaha, Mekki; Grohs, Cécile; Allais-Bonnet, Aurélie; Philippe, Maëlle; Vallée, Amélie; Amigues, Yves; Hayes, Benjamin J; Boichard, Didier; Capitan, Aurélien

2018-04-18

Researching depletions in homozygous genotypes for specific haplotypes among the large cohorts of animals genotyped for genomic selection is a very efficient strategy to map recessive lethal mutations. In this study, by analyzing real or imputed Illumina BovineSNP50 (Illumina Inc., San Diego, CA) genotypes from more than 250,000 Holstein animals, we identified a new locus called HH6 showing significant negative effects on conception rate and nonreturn rate at 56 d in at-risk versus control mating. We fine-mapped this locus in a 1.1-Mb interval and analyzed genome sequence data from 12 carrier and 284 noncarrier Holstein bulls. We report the identification of a strong candidate mutation in the gene encoding SDE2 telomere maintenance homolog (SDE2), a protein essential for genomic stability in eukaryotes. This A-to-G transition changes the initiator ATG (methionine) codon to ACG because the gene is transcribed on the reverse strand. Using RNA sequencing and quantitative reverse-transcription PCR, we demonstrated that this mutation does not significantly affect SDE2 splicing and expression level in heterozygous carriers compared with control animals. Initiation of translation at the closest in-frame methionine codon would truncate the SDE2 precursor by 83 amino acids, including the cleavage site necessary for its activation. Finally, no homozygote for the G allele was observed in a large population of nearly 29,000 individuals genotyped for the mutation. The low frequency (1.3%) of the derived allele in the French population and the availability of a diagnostic test on the Illumina EuroG10K SNP chip routinely used for genomic evaluation will enable rapid and efficient selection against this deleterious mutation. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The Effect of Protoplanetary Disk Cooling Times on the Formation of Gas Giant Planets by Gravitational Instability

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

Boss, Alan P., E-mail: aboss@carnegiescience.edu

2017-02-10

Observational evidence exists for the formation of gas giant planets on wide orbits around young stars by disk gravitational instability, but the roles of disk instability and core accretion for forming gas giants on shorter period orbits are less clear. The controversy extends to population synthesis models of exoplanet demographics and to hydrodynamical models of the fragmentation process. The latter refers largely to the handling of radiative transfer in three-dimensional (3D) hydrodynamical models, which controls heating and cooling processes in gravitationally unstable disks, and hence dense clump formation. A suite of models using the β cooling approximation is presented here.more » The initial disks have masses of 0.091 M {sub ⊙} and extend from 4 to 20 au around a 1 M {sub ⊙} protostar. The initial minimum Toomre Qi values range from 1.3 to 2.7, while β ranges from 1 to 100. We show that the choice of Q {sub i} is equal in importance to the β value assumed: high Q{sub i} disks can be stable for small β , when the initial disk temperature is taken as a lower bound, while low Q{sub i} disks can fragment for high β . These results imply that the evolution of disks toward low Q{sub i} must be taken into account in assessing disk fragmentation possibilities, at least in the inner disk, i.e., inside about 20 au. The models suggest that if low Q{sub i} disks can form, there should be an as yet largely undetected population of gas giants orbiting G dwarfs between about 6 au and 16 au.« less

The Population Reference Sample, POPRES: A Resource for Population, Disease, and Pharmacological Genetics Research

PubMed Central

Nelson, Matthew R.; Bryc, Katarzyna; King, Karen S.; Indap, Amit; Boyko, Adam R.; Novembre, John; Briley, Linda P.; Maruyama, Yuka; Waterworth, Dawn M.; Waeber, Gérard; Vollenweider, Peter; Oksenberg, Jorge R.; Hauser, Stephen L.; Stirnadel, Heide A.; Kooner, Jaspal S.; Chambers, John C.; Jones, Brendan; Mooser, Vincent; Bustamante, Carlos D.; Roses, Allen D.; Burns, Daniel K.; Ehm, Margaret G.; Lai, Eric H.

2008-01-01

Technological and scientific advances, stemming in large part from the Human Genome and HapMap projects, have made large-scale, genome-wide investigations feasible and cost effective. These advances have the potential to dramatically impact drug discovery and development by identifying genetic factors that contribute to variation in disease risk as well as drug pharmacokinetics, treatment efficacy, and adverse drug reactions. In spite of the technological advancements, successful application in biomedical research would be limited without access to suitable sample collections. To facilitate exploratory genetics research, we have assembled a DNA resource from a large number of subjects participating in multiple studies throughout the world. This growing resource was initially genotyped with a commercially available genome-wide 500,000 single-nucleotide polymorphism panel. This project includes nearly 6,000 subjects of African-American, East Asian, South Asian, Mexican, and European origin. Seven informative axes of variation identified via principal-component analysis (PCA) of these data confirm the overall integrity of the data and highlight important features of the genetic structure of diverse populations. The potential value of such extensively genotyped collections is illustrated by selection of genetically matched population controls in a genome-wide analysis of abacavir-associated hypersensitivity reaction. We find that matching based on country of origin, identity-by-state distance, and multidimensional PCA do similarly well to control the type I error rate. The genotype and demographic data from this reference sample are freely available through the NCBI database of Genotypes and Phenotypes (dbGaP). PMID:18760391

Probabilistic Fracture Mechanics of Reactor Pressure Vessels with Populations of Flaws

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

Spencer, Benjamin; Backman, Marie; Williams, Paul

This report documents recent progress in developing a tool that uses the Grizzly and RAVEN codes to perform probabilistic fracture mechanics analyses of reactor pressure vessels in light water reactor nuclear power plants. The Grizzly code is being developed with the goal of creating a general tool that can be applied to study a variety of degradation mechanisms in nuclear power plant components. Because of the central role of the reactor pressure vessel (RPV) in a nuclear power plant, particular emphasis is being placed on developing capabilities to model fracture in embrittled RPVs to aid in the process surrounding decisionmore » making relating to life extension of existing plants. A typical RPV contains a large population of pre-existing flaws introduced during the manufacturing process. The use of probabilistic techniques is necessary to assess the likelihood of crack initiation at one or more of these flaws during a transient event. This report documents development and initial testing of a capability to perform probabilistic fracture mechanics of large populations of flaws in RPVs using reduced order models to compute fracture parameters. The work documented here builds on prior efforts to perform probabilistic analyses of a single flaw with uncertain parameters, as well as earlier work to develop deterministic capabilities to model the thermo-mechanical response of the RPV under transient events, and compute fracture mechanics parameters at locations of pre-defined flaws. The capabilities developed as part of this work provide a foundation for future work, which will develop a platform that provides the flexibility needed to consider scenarios that cannot be addressed with the tools used in current practice.« less

Interventions to increase use of services; Mental Health Awareness in Nigeria.

PubMed

Eaton, Julian; Nwefoh, Emeka; Okafor, Godwin; Onyeonoro, Ugochukwu; Nwaubani, Kenneth; Henderson, Claire

2017-01-01

Mental health services in Nigeria consist mainly of large government psychiatric hospitals and there are very few mental health professionals to serve the large population of the country. However, more recently, community mental health services, which have been shown to improve access to care and clinical outcomes are beginning to develop in some locations. Despite efforts to promote more accessible services, low levels of knowledge about effective treatment of mental disorders means that even where these services are available, a very small proportion of people utilise these services. Therefore interventions to increase service use are an essential component of health system. This intervention was designed to increase use of a mental health services through the work of community-based Village Health Workers. Fifteen Village Health Workers in each Local Government Area (district) were selected and trained to create mental health awareness in communities. Their function also include identification and referral of persons with mental illness to trained mental health nurses in the clinics. Attendance data prior to and after intervention were collected and compared. The incident rate for initial period of intervention is five times higher than the baseline rate (95% CI; 3.42-7.56; p < 0.001) though this diminished in the long term, levelling off above initial baseline. This study demonstrated that addition of awareness raising using volunteers in communities as part of health programme implementation can increase services use by a population. Mechanisms such as informing populations of the existence of a service which they were previously lacking; explanation of causation of mental illness and achieving community leaders' support for a new service can make investment in services more efficient by increasing attendance.

Modernization is associated with intensive breastfeeding patterns in the Bolivian Amazon.

PubMed

Veile, Amanda; Martin, Melanie; McAllister, Lisa; Gurven, Michael

2014-01-01

For many traditional, non-industrialized populations, intensive and prolonged breastfeeding buffers infant health against poverty, poor sanitation, and limited health care. Due to novel influences on local economies, values, and beliefs, the traditional and largely beneficial breastfeeding patterns of such populations may be changing to the detriment of infant health. To assess if and why such changes are occurring in a traditional breastfeeding population, we document breastfeeding patterns in the Bolivian Tsimane, a forager-horticulturalist population in the early stages of modernization. Three predictions are developed and tested to evaluate the general hypothesis that modernizing influences encourage less intensive breastfeeding in the Tsimane: 1) Tsimane mothers in regions of higher infant mortality will practice more intensive BF; 2) Tsimane mothers who are located closer to a local market town will practice more intensive BF; and 3) Older Tsimane mothers will practice more intensive BF. Predictions were tested using a series of maternal interviews (from 2003 to 2011, n = 215) and observations of mother-infant dyads (from 2002 to 2007, n = 133). Tsimane breastfeeding patterns were generally intensive: 72% of mothers reported initiating BF within a few hours of birth, mean (±SD) age of CF introduction was 4.1 ± 2.0 months, and mean (±SD) weaning age was 19.2 ± 7.3 months. There was, however, intra-population variation in several dimensions of breastfeeding (initiation, frequency, duration, and complementary feeding). Contrary to our predictions, breastfeeding was most intensive in the most modernized Tsimane villages, and maternal age was not a significant predictor of breastfeeding patterns. Regional differences accounted for variation in most dimensions of breastfeeding (initiation, frequency, and complementary feeding). Future research should therefore identify constraints on breastfeeding in the less modernized Tsimane regions, and examine the formation of maternal beliefs regarding infant feeding. Copyright © 2013 Elsevier Ltd. All rights reserved.

Which Triple Aim related measures are being used to evaluate population management initiatives? An international comparative analysis.

PubMed

Hendrikx, Roy J P; Drewes, Hanneke W; Spreeuwenberg, Marieke; Ruwaard, Dirk; Struijs, Jeroen N; Baan, Caroline A

2016-05-01

Population management (PM) initiatives are introduced in order to create sustainable health care systems. These initiatives should focus on the continuum of health and well-being of a population by introducing interventions that integrate various services. To be successful they should pursue the Triple Aim, i.e. simultaneously improve population health and quality of care while reducing costs per capita. This study explores how PM initiatives measure the Triple Aim in practice. An exploratory search was combined with expert consultations to identify relevant PM initiatives. These were analyzed based on general characteristics, utilized measures and related selection criteria. In total 865 measures were used by 20 PM initiatives. All quality of care domains were included by at least 11 PM initiatives, while most domains of population health and costs were included by less than 7 PM initiatives. Although their goals showed substantial overlap, the measures applied showed few similarities between PM initiatives and were predominantly selected based on local priority areas and data availability. Most PM initiatives do not measure the full scope of the Triple Aim. Additionally, variety between measures limits comparability between PM initiatives. Consensus on the coverage of Triple Aim domains and a set of standardized measures could further both the inclusion of the various domains as well as the comparability between PM initiatives. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[Poliomyelitis--Challenges for the Last Mile of the Eradication Programme].

PubMed

Müller, O; Jahn, A; Razum, O

2016-04-01

The World Health Organisation initiated the Global Polio Eradication Initiative in the year 1988. With the large-scale application of routine and mass vaccinations in children under the age of 5 years, polio disease has become restricted to only 3 endemic countries (Afghanistan, Pakistan and Nigeria) by today. However, since the beginning of the 21st century, increasing numbers of secondary polio epidemics have been observed which were triggered through migration, political turmoil and weak health systems. In addition, there emerged serious technical (e. g., back-mutations of oral vaccine virus to wild virus) and socio-political (refusal of vaccinations in Muslim populations of Nigeria and Pakistan) problems with the vaccination in the remaining endemic countries. It thus appears questionable if the current eradiation initiative will reach its goal in the foreseeable future. © Georg Thieme Verlag KG Stuttgart · New York.

Sea otters in captivity: applications and implications of husbandry development, public display, scientific research and management, and rescue and rehabilitation for sea otter conservation

USGS Publications Warehouse

VanBlaricom, Glenn R.; Belting, Traci F.; Triggs, Lisa H.

2015-01-01

Studies of sea otters in captivity began in 1932, producing important insights for conservation. Soviet (initiated in 1932) and United States (1951) studies provided information on captive otter husbandry, setting the stage for eventual large-scale translocations as tools for population restoration. Early studies also informed effective housing of animals in zoos and aquaria, with sea otters first publicly displayed in 1954. Surveys credited displayed otters in convincing the public of conservation values. After early studies, initial scientific data for captive sea otters in aquaria came from work initiated in 1956, and from dedicated research facilities beginning in 1968. Significant achievements have been made in studies of behavior, physiology, reproduction, and high-priority management issues. Larger-scale projects involving translocation and oil spill response provided extensive insights into stress reactions, water quality issues in captivity, and effects of oil spills.

A Framework for Monitoring Progress Using Summary Measures of Health.

PubMed

Madans, Jennifer H; Weeks, Julie D

2016-10-01

Initiatives designed to monitor health typically incorporate numerous specific measures of health and the health system to assess improvements, or lack thereof, for policy and program purposes. The addition of summary measures provides overarching information which is essential for determining whether the goals of such initiatives are met. Summary measures are identified that relate to the individual indicators but that also reflect movement in the various parts of the system. A hierarchical framework that is conceptually consistent and which utilizes a succinct number of summary measures incorporating indicators of functioning and participation is proposed. While a large set of individual indicators can be useful for monitoring progress, these individual indicators do not provide an overall evaluation of health, defined broadly, at the population level. A hierarchical framework consisting of summary measures is important for monitoring the success of health improvement initiatives. © The Author(s) 2016.

The co-evolution of cultures, social network communities, and agent locations in an extension of Axelrod’s model of cultural dissemination

NASA Astrophysics Data System (ADS)

Pfau, Jens; Kirley, Michael; Kashima, Yoshihisa

2013-01-01

We introduce a variant of the Axelrod model of cultural dissemination in which agents change their physical locations, social links, and cultures. Numerical simulations are used to investigate the evolution of social network communities and the cultural diversity within and between these communities. An analysis of the simulation results shows that an initial peak in the cultural diversity within network communities is evident before agents segregate into a final configuration of culturally homogeneous communities. Larger long-range interaction probabilities facilitate the initial emergence of culturally diverse network communities, which leads to a more pronounced initial peak in cultural diversity within communities. At equilibrium, the number of communities, and hence cultures, increases when the initial cultural diversity increases. However, the number of communities decreases when the lattice size or population density increases. A phase transition between two regimes of initial cultural diversity is evident. For initial diversities below a critical value, a single network community and culture emerges that dominates the population. For initial diversities above the critical value, multiple culturally homogeneous communities emerge. The critical value of initial diversity at which this transition occurs increases with increasing lattice size and population density and generally with increasing absolute population size. We conclude that larger initial diversities promote cultural heterogenization, while larger lattice sizes, population densities, and in fact absolute population sizes promote homogenization.

Divergence between human populations estimated from linkage disequilibrium.

PubMed

Sved, John A; McRae, Allan F; Visscher, Peter M

2008-12-01

Observed linkage disequilibrium (LD) between genetic markers in different populations descended independently from a common ancestral population can be used to estimate their absolute time of divergence, because the correlation of LD between populations will be reduced each generation by an amount that, approximately, depends only on the recombination rate between markers. Although drift leads to divergence in allele frequencies, it has less effect on divergence in LD values. We derived the relationship between LD and time of divergence and verified it with coalescent simulations. We then used HapMap Phase II data to estimate time of divergence between human populations. Summed over large numbers of pairs of loci, we find a positive correlation of LD between African and non-African populations at levels of up to approximately 0.3 cM. We estimate that the observed correlation of LD is consistent with an effective separation time of approximately 1,000 generations or approximately 25,000 years before present. The most likely explanation for such relatively low separation times is the existence of substantial levels of migration between populations after the initial separation. Theory and results from coalescent simulations confirm that low levels of migration can lead to a downward bias in the estimate of separation time.

The Exercise is Medicine Global Health Initiative: a 2014 update.

PubMed

Lobelo, Felipe; Stoutenberg, Mark; Hutber, Adrian

2014-12-01

A third of the world's population does not engage in recommended levels of physical activity (PA), leading to substantial health and economic burdens. The healthcare sector offers a variety of resources that can help counsel, refer and deliver PA promotion programmes for purposes of primordial, primary, secondary and tertiary prevention. Substantial evidence already exists in support of multipronged PA counselling, prescription and referral strategies, in particular those linking healthcare and community-based resources. The Exercise is Medicine (EIM) initiative was introduced in 2007 to advance the implementation of evidence-based strategies to elevate the status of PA in healthcare. In this article, we describe the evolution and global expansion of the EIM initiative, its components, their implementation, an evaluation framework and future initiative activities. Until now, EIM has a presence in 39 countries with EIM Regional Centers established in North America, Latin America, Europe, Africa, Southeast Asia, China and Australasia. The EIM Global Health Initiative is transitioning from its initial phase of infrastructure and awareness building to a phase of programme implementation, with an emphasis in low-to-middle income countries, where 80% of deaths due to non-communicable diseases already occur, but where a large gap in research and implementation of PA strategies exists. Broad implementation of PA counselling and referral systems, as clinical practice standard of care, has the potential to improve PA at the population level by complementing and leveraging other efforts and to contribute to achieving global targets for the reduction of inactivity and related morbidity and mortality. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Fossil and genetic history of a pinyon pine (Pinus edulis) isolate

USGS Publications Warehouse

Betancourt, J.L.; Schuster, W.S.; Mitton, J.B.; Anderson, R. Scott

1991-01-01

The most isolated northern stand of Colorado pinyon pine at Owl Canyon, Colorado, has a broad and flat size class distribution common to population expansions, with the largest and oldest trees near the center of the grove. Analyses of fossil packrat Neotoma middens within the grove indicate that the stand originated by long-distance dispersal rather than by vicariance. The 5000-yr pollen and macrofossil record suggests that pinyon pine colonized the site sometime between 1290-420 yr BP, the latter age corresponding to the oldest tree in the stand. Electrophoretic data show that this colonization was not attended by typical founder effects predicted by theory or observed for other known founder events. The Owl Canyon stand has not suffered significant losses in genetic variation relative to likely source populations. Large initial population size, multiple founding events, rapid population growth, or selection favoring heterozygous genotypes could all explain the high heterozygosity and only slightly reduced polymorphism and number of alleles per locus. -from Authors

Impacts from control operations on a recreationally hunted feral swine population at a large military installation in Florida.

PubMed

Engeman, Richard; Hershberger, Troy; Orzell, Steve; Felix, Rodney; Killian, Gary; Woolard, John; Cornman, Jon; Romano, David; Huddleston, Chet; Zimmerman, Pat; Barre, Chris; Tillman, Eric; Avery, Michael

2014-06-01

Feral swine were targeted for control at Avon Park Air Force Range in south-central Florida to avert damage to sensitive wetland habitats on the 40,000-ha base. We conducted a 5-year study to assess impacts from control to this population that had been recreationally hunted for many years. Control was initiated in early 2009. The feral swine population was monitored from 2008 to 2012 using a passive tracking index (PTI) during the dry and wet seasons and using recreational hunter take rates from the dry season. All three indices showed substantial feral swine declines after implementing control, with indices leveling for the final two study years. Military missions and recreational hunting seasons impacted temporal and spatial consistency of control application, thereby limiting further impacts of control efforts on the feral swine population. The PTI was also able to monitor coyotes, another invasive species on the base, and detect Florida black bear and Florida panther, species of particular concern.

[Effect of BRL 25000 (clavulanic acid-amoxicillin) on bacterial flora in human feces].

PubMed

Motohiro, T; Tanaka, K; Koga, T; Shimada, Y; Tomita, N; Sakata, Y; Fujimoto, T; Nishiyama, T; Kuda, N; Ishimoto, K

1985-02-01

BRL 25000 (187.5 and 375 mg tablets), a formulation of CVA-K and AMPC in the ratio of 1:2, and AMPC (as control drug) were administered to healthy volunteers, aged 20 approximately 28 years and weighing 60 approximately 85 kg (68.8 kg, on average). Each drug was administered 3 times a day (after meals) for 5 days and the volunteers were separated into 3 groups of 4 subjects each. The effect on the fecal flora was studied before dosage, during administration (day 3 and 5) and day 3 and 5 after the administration course was completed. Studies were undertaken to isolate C. difficile on the last day of administration and 3 and 5 days after administration had ceased. Fecal concentrations and the susceptibility of the isolates to AMPC, CVA-K and BRL 25000 were measured. Side effects and laboratory findings were studied. The results obtained were as follows: 1. In BRL 25000 (187.5 mg X 3/day) group, the population of E. coli was on average, 1 X 10(6) approximately 9 X 10(6) cells/g feces before initiation of administration and it increased by 2 logarithms 3 and 5 days after initiation of administration. By 3 and 5 days after end of administration, the E. coli population was similar to the initial population. The population of Klebsiella sp. was 1 X 10(6) approximately 9 X 10(6) cells/g feces on average before commencement of dosage and it increased by 2 logarithms 3 days after initiation of administration but there was no consistent change in the Klebsiella sp. population thereafter. The Enterobacter sp., population was not consistent neither was the population of other Enterobacteriaceae. In total, the mean Enterobacteriaceae population was 1 X 10(7) approximately 9 X 10(7) cells/g feces before initiation of administration and increased by 2 logarithms 3 days after initiation of administration, and then returned to the initial level 5 days after end of administration. No consistent changes in population were noted for the other Gram-negative bacilli. The Staphylococcus sp. population was 1 X 10(6) approximately 9 X 10(6) cells/g feces on average before initiation of administration. This organism was detected in only 1 case 3 days after initiation of administration and in another 5 days after initiation of administration, thereafter, the population was similar to the initial population.(ABSTRACT TRUNCATED AT 400 WORDS)

Symptoms of carbon monoxide poisoning do not correlate with the initial carboxyhemoglobin level.

PubMed

Hampson, Neil B; Dunn, Susan L

2012-01-01

Symptoms in carbon monoxide (CO) poisoned patients have traditionally been described as being related to corresponding carboxyhemoglobin (COHb) levels without substantive support for the relationship. This study sought to determine whether prospectively collected symptoms correlate with specific COHB level ranges in a large population of CO-poisoned patients. Data from patients reported in the initial two years of operation of the joint UHMS/CDC CO Poisoning Surveillance System were used to compare presenting COHb levels with symptoms collected with a standardized questionnaire. Data from 1,323 CO-poisoned patients referred for hyperbaric oxygen therapy from August 2008 to July 2010 were analyzed with regard to initial COHb level and symptoms. Of approximately 50 categories of symptoms reported, none was associated with a specific range of COHb levels. While symptoms are common in acute CO poisoning, none can be directly correlated to COHb levels, even in a population of more than 1,000 patients. The concept of a table relating specific symptoms to specific COHb levels is invalid. One such table that has often been published comes from a 1923 U.S. government publication and appears to be based at least in part upon the symptoms experienced by three men in a total of 10 low-level laboratory CO exposures.

Carry-over effects of the social environment on future divorce probability in a wild bird population

PubMed Central

Culina, Antica; Hinde, Camilla A.; Sheldon, Ben C.

2015-01-01

Initial mate choice and re-mating strategies (infidelity and divorce) influence individual fitness. Both of these should be influenced by the social environment, which determines the number and availability of potential partners. While most studies looking at this relationship take a population-level approach, individual-level responses to variation in the social environment remain largely unstudied. Here, we explore carry-over effects on future mating decisions of the social environment in which the initial mating decision occurred. Using detailed data on the winter social networks of great tits, we tested whether the probability of subsequent divorce, a year later, could be predicted by measures of the social environment at the time of pairing. We found that males that had a lower proportion of female associates, and whose partner ranked lower among these, as well as inexperienced breeders, were more likely to divorce after breeding. We found no evidence that a female's social environment influenced the probability of divorce. Our findings highlight the importance of the social environment that individuals experience during initial pair formation on later pairing outcomes, and demonstrate that such effects can be delayed. Exploring these extended effects of the social environment can yield valuable insights into processes and selective pressures acting upon the mating strategies that individuals adopt. PMID:26468239

Inversion-based propofol dosing for intravenous induction of hypnosis

NASA Astrophysics Data System (ADS)

Padula, F.; Ionescu, C.; Latronico, N.; Paltenghi, M.; Visioli, A.; Vivacqua, G.

2016-10-01

In this paper we propose an inversion-based methodology for the computation of a feedforward action for the propofol intravenous administration during the induction of hypnosis in general anesthesia. In particular, the typical initial bolus is substituted with a command signal that is obtained by predefining a desired output and by applying an input-output inversion procedure. The robustness of the method has been tested by considering a set of patients with different model parameters, which is representative of a large population.

Understanding the economics of succeeding in disease management.

PubMed

Shulkin, D J

1999-04-01

If implemented with the proper resource commitment, disease management can have a significant effect on the health of an organization's patient population. However, it is unlikely that even the noblest of strategic initiatives will survive long without a compelling business imperative. After analyzing the business case, many organizations have committed large amounts of resources to building disease management programs. Yet these issues are still being formulated. The author discusses five issues that are key to understanding the economics of disease management.

Please don't misuse the museum: 'declines' may be statistical

USGS Publications Warehouse

Grant, Evan H. Campbell

2015-01-01

Detecting declines in populations at broad spatial scales takes enormous effort, and long-term data are often more sparse than is desired for estimating trends, identifying drivers for population changes, framing conservation decisions or taking management actions. Museum records and historic data can be available at large scales across multiple decades, and are therefore an attractive source of information on the comparative status of populations. However, changes in populations may be real (e.g., in response to environmental covariates) or resulting from variation in our ability to observe the true population response (also possibly related to environmental covariates). This is a (statistical) nuisance in understanding the true status of a population. Evaluating statistical hypotheses alongside more interesting ecological ones is important in the appropriate use of museum data. Two statistical considerations are generally applicable to use of museum records: first without initial random sampling, comparison with contemporary results cannot provide inference to the entire range of a species, and second the availability of only some individuals in a population may respond to environmental changes. Changes in the availability of individuals may reduce the proportion of the population that is present and able to be counted on a given survey event, resulting in an apparent decline even when population size is stable.

Climate variability, human wildlife conflict and population dynamics of lions Panthera leo.

PubMed

Trinkel, Martina

2013-04-01

Large carnivores are threatened by habitat loss, declining prey populations and direct persecution. Pride dynamics of eight lion prides in the centre of the Etosha National Park, Namibia are described during a 16-year study. Since the beginning of the 1980s, the number of adult and subadult lions declined continuously to two third of its initial population size, and reached a new equilibrium in the 1990s. Pride sizes decreased from 6.3 adult females in 1989 to 2.8 lionesses in 1997. While the number of adult females declined continuously, the number of adult males, subadult females and subadult males remained constant over the years. A severe drought period, lasting for more than 20 years, led to declining prey populations inside the lions' territory. Besides declining prey populations, conflict with humans at the border of Etosha puts substantial pressure onto the lion population: 82% of all known lion mortalities were caused by humans, and most of these consisted of adult females (28%) and subadult males (29%). I postulate that the considerable decline in the lion population is a response to declining prey populations, and although the human predator conflict is severe, it does not seem to limit the size of Etosha's lion population.

Climate variability, human wildlife conflict and population dynamics of lions Panthera leo

NASA Astrophysics Data System (ADS)

Trinkel, Martina

2013-04-01

Large carnivores are threatened by habitat loss, declining prey populations and direct persecution. Pride dynamics of eight lion prides in the centre of the Etosha National Park, Namibia are described during a 16-year study. Since the beginning of the 1980s, the number of adult and subadult lions declined continuously to two third of its initial population size, and reached a new equilibrium in the 1990s. Pride sizes decreased from 6.3 adult females in 1989 to 2.8 lionesses in 1997. While the number of adult females declined continuously, the number of adult males, subadult females and subadult males remained constant over the years. A severe drought period, lasting for more than 20 years, led to declining prey populations inside the lions' territory. Besides declining prey populations, conflict with humans at the border of Etosha puts substantial pressure onto the lion population: 82 % of all known lion mortalities were caused by humans, and most of these consisted of adult females (28 %) and subadult males (29 %). I postulate that the considerable decline in the lion population is a response to declining prey populations, and although the human predator conflict is severe, it does not seem to limit the size of Etosha's lion population.

[Health care personnel in Norway].

PubMed

Bast-Pettersen, R

1995-11-10

In 1990, the Nordic Council of Ministers initiated the joint Nordic project on "Work and health among health care personnel". The main aims were: To review and evaluate research data concerning the health and work of health care personnel in the Nordic countries, initiate joint Nordic projects and promote collaboration between Nordic researchers. Altogether more than one million people in the Nordic countries are employed in the health care sector, or almost 10% of the labour force. In all the Nordic countries the labour force in the health sector is dominated by women; the proportion of women being between 84 and 87%. In Norway and Sweden a large share of the labour force works part time. When controlled for sex and level of education, sick leave is the same among health personnel as among the general working population. As in the whole population, sick leave is higher among women, and among persons with a lower level of education. In general, workers in the health care sector in the Nordic countries run no greater risk of developing occupationally related injuries than other workers do. In a register-based study of Swedish workers it was found that the risk of being absent from work because of violence or threats is higher among health personnel than in the general working population.

Perspectives on Intracluster Enrichment and the Stellar Initial Mass Function in Elliptical Galaxies

NASA Technical Reports Server (NTRS)

Lowenstein, Michael

2013-01-01

The amount of metals in the Intracluster Medium (ICM) in rich galaxy clusters exceeds that expected based on the observed stellar population by a large factor. We quantify this discrepancy--which we term the "cluster elemental abundance paradox"--and investigate the required properties of the ICM-enriching population. The necessary enhancement in metal enrichment may, in principle, originate in the observed stellar population if a larger fraction of stars in the supernova-progenitor mass range form from an initial mass function (IMF) that is either bottom-light or top-heavy, with the latter in some conflict with observed ICM abundance ratios. Other alternatives that imply more modest revisions to the IMF, mass return and remnant fractions, and primordial fraction, posit an increase in the fraction of 3-8 solar mass stars that explode as SNIa or assume that there are more stars than conventionally thought--although the latter implies a high star formation efficiency. We discuss the feasibility of these various solutions and the implications for the diversity of star formation, the process of elliptical galaxy formation, and the nature of this hidden source of ICM metal enrichment in light of recent evidence of an elliptical galaxy IMF that, because it is skewed to low masses, deepens the paradox.

Global optimization and reflectivity data fitting for x-ray multilayer mirrors by means of genetic algorithms

NASA Astrophysics Data System (ADS)

Sanchez del Rio, Manuel; Pareschi, Giovanni

2001-01-01

The x-ray reflectivity of a multilayer is a non-linear function of many parameters (materials, layer thicknesses, densities, roughness). Non-linear fitting of experimental data with simulations requires to use initial values sufficiently close to the optimum value. This is a difficult task when the space topology of the variables is highly structured, as in our case. The application of global optimization methods to fit multilayer reflectivity data is presented. Genetic algorithms are stochastic methods based on the model of natural evolution: the improvement of a population along successive generations. A complete set of initial parameters constitutes an individual. The population is a collection of individuals. Each generation is built from the parent generation by applying some operators (e.g. selection, crossover, mutation) on the members of the parent generation. The pressure of selection drives the population to include 'good' individuals. For large number of generations, the best individuals will approximate the optimum parameters. Some results on fitting experimental hard x-ray reflectivity data for Ni/C multilayers recorded at the ESRF BM5 are presented. This method could be also applied to the help in the design of multilayers optimized for a target application, like for an astronomical grazing-incidence hard X-ray telescopes.

An integrated approach to preventing cardiovascular disease: community-based approaches, health system initiatives, and public health policy.

PubMed

Karwalajtys, Tina; Kaczorowski, Janusz

2010-01-01

Cardiovascular disease (CVD) is largely the product of interactions among modifiable risk factors that are common in developed nations and increasingly of concern in developing countries. Hypertension is an important precursor to the development of CVD, and although detection and treatment rates have improved in recent years in some jurisdictions, effective strategies and policies supporting a shift in distribution of risk factors at the population level remain paramount. Challenges in managing cardiovascular health more effectively include factors at the patient, provider, and system level. Strategies to reduce hypertension and CVD should be population based, incorporate multilevel, multicomponent, and socioenvironmental approaches, and integrate community resources with public health and clinical care. There is an urgent need to improve monitoring and management of risk factors through community-wide, primary care-linked initiatives, increase the evidence base for community-based prevention strategies, further develop and evaluate promising program components, and develop new approaches to support healthy lifestyle behaviors in diverse age, socioeconomic, and ethnocultural groups. Policy and system changes are critical to reduce risk in populations, including legislation and public education to reduce dietary sodium and trans-fatty acids, food pricing policies, and changes to health care delivery systems to explicitly support prevention and management of CVD.

Choice and privatisation in Swedish primary care.

PubMed

Anell, Anders

2011-10-01

In 2007, a new wave of local reforms involving choice for the population and privatisation of providers was initiated in Swedish primary care. Important objectives behind reforms were to strengthen the role of primary care and to improve performance in terms of access and responsiveness. The purpose of this article was to compare the characteristics of the new models and to discuss changes in financial incentives for providers and challenges regarding governance from the part of county councils. A majority of the models being introduced across the 21 county councils can best be described as innovative combinations between a comprehensive responsibility for providers and significant degrees of freedom regarding choice for the population. Key financial characteristics of fixed payment and comprehensive financial responsibility for providers may create financial incentives to under-provide care. Informed choices by the population, in combination with reasonably low barriers for providers to enter the primary care market, should theoretically counterbalance such incentives. To facilitate such competition is indeed a challenge, not only because of difficulties in implementing informed choices but also because the new models favour large and/or horizontally integrated providers. To prevent monopolistic behaviour, county councils may have to accept more competition as well as more governance over clinical practice than initially intended.

Recruitment and Participation of Recreational Runners in a Large Epidemiological and Genetic Research Study: Retrospective Data Analysis

PubMed Central

Manzanero, Silvia; Kozlovskaia, Maria; Vlahovich, Nicole

2018-01-01

Background With the increasing capacity for remote collection of both data and samples for medical research, a thorough assessment is needed to determine the association of population characteristics and recruitment methodologies with response rates. Objective The aim of this research was to assess population representativeness in a two-stage study of health and injury in recreational runners, which consisted of an epidemiological arm and genetic analysis. Methods The cost and success of various classical and internet-based methods were analyzed, and demographic representativeness was assessed for recruitment to the epidemiological survey, reported willingness to participate in the genetic arm of the study, actual participation, sample return, and approval for biobank storage. Results A total of 4965 valid responses were received, of which 1664 were deemed eligible for genetic analysis. Younger age showed a negative association with initial recruitment rate, expressed willingness to participate in genetic analysis, and actual participation. Additionally, female sex was associated with higher initial recruitment rates, and ethnic origin impacted willingness to participate in the genetic analysis (all P<.001). Conclusions The sharp decline in retention through the different stages of the study in young respondents suggests the necessity to develop specific recruitment and retention strategies when investigating a young, physically active population. PMID:29792293

Monitoring the welfare of polar bear populations in a rapidly changing Arctic

USGS Publications Warehouse

Atwood, Todd C.; Duncan, Colleen G.; Patyk, Kelly A.; Sonsthagen, Sarah A.

2017-01-01

Most programs for monitoring the welfare of wildlife populations support efforts aimed at reaching discrete management objectives, like mitigating conflict with humans. While such programs can be effective, their limited scope may preclude systemic evaluations needed for large-scale conservation initiatives, like the recovery of at-risk species. We discuss select categories of metrics that can be used to monitor how polar bears (Ursus maritimus) are responding to the primary threat to their long-term persistence—loss of sea ice habitat due to the unabated rise in atmospheric greenhouse gas (GHG; e.g., CO2) concentrations—that can also provide information on ecosystem function and health. Monitoring key aspects of polar bear population dynamics, spatial behavior, health and resiliency can provide valuable insight into ecosystem state and function, and could be a powerful tool for achieving Arctic conservation objectives, particularly those that have transnational policy implications.

Transcription termination factor Rho and microbial phenotypic heterogeneity.

PubMed

Bidnenko, Elena; Bidnenko, Vladimir

2018-06-01

Populations of genetically identical microorganisms exhibit high degree of cell-to-cell phenotypic diversity even when grown in uniform environmental conditions. Heterogeneity is a genetically determined trait, which ensures bacterial adaptation and survival in the ever changing environmental conditions. Fluctuations in gene expression (noise) at the level of transcription initiation largely contribute to cell-to-cell variability within population. Not surprisingly, the analyses of the mechanisms driving phenotypic heterogeneity are mainly focused on the activity of promoters and transcriptional factors. Less attention is currently given to a role of intrinsic and factor-dependent transcription terminators. Here, we discuss recent advances in understanding the regulatory role of the multi-functional transcription termination factor Rho, the major inhibitor of pervasive transcription in bacteria and the emerging global regulator of gene expression. We propose that termination activity of Rho might be among the mechanisms by which cells manage the intensity of transcriptional noise, thus affecting population heterogeneity.

Evidence For Rapid Spatiotemporal Changes in Genetic Structure of an Alien Whitefly During Initial Invasion

PubMed Central

Chu, Dong; Guo, Dong; Tao, Yunli; Jiang, Defeng; Li, Jie; Zhang, Youjun

2014-01-01

The sweetpotato whitefly Bemisia tabaci Q species is a recent invader and important pest of agricultural crops in China. This research tested the hypothesis that the Q populations that establish in agricultural fields in northern China each year are derived from multiple secondary introductions and/or local populations that overwinter in greenhouses (the pest cannot survive winters in the field in northern China). Here, we report the evidence that the Q populations in agricultural fields mainly derive from multiple secondary introductions. In addition, the common use of greenhouses during the winter in certain locations in northern China helps increase the genetic diversity and the genetic structure of the pest. The genetic structure information generated from this long-term and large-scale field analysis increases our understanding of B. tabaci Q as an invasive pest and has important implications for B. tabaci Q management. PMID:24637851

Spectral synthesis in the ultraviolet. II - Stellar populations and star formation in blue compact galaxies

NASA Technical Reports Server (NTRS)

Fanelli, Michael N.; O'Connell, Robert W.; Thuan, Trinh X.

1988-01-01

An initial attempt to apply optimizing spectral synthesis techniques to the far-UV spectra of blue compact galaxies (BCGs) is presented. The far-UV absorption-line spectra of the galaxies are clearly composite, with the signatures of the main-sequence types between O3 and mid-A. Most of the low-ionization absorption lines have a stellar origin. The Si IV and C IV features in several objects have P Cygni profiles. In Haro I the strength of Si IV indicates a significant blue supergiant population. The metal-poor blue compact dwarf Mrk 209 displays weak absorption lines, evidence that the stellar component has the same low metallicity as observed in the ionized gas. Good fits to the data are obtained the technique of optimizing population synthesis. The solutions yield stellar luminosity functions which display large discontinuities, indicative of discrete star formation episodes or bursts. The amount of UV extinction is low.

Getting quantitative about consequences of cross-ecosystem resource subsidies on recipient consumers

USGS Publications Warehouse

Richardson, John S.; Wipfli, Mark S.

2016-01-01

Most studies of cross-ecosystem resource subsidies have demonstrated positive effects on recipient consumer populations, often with very large effect sizes. However, it is important to move beyond these initial addition–exclusion experiments to consider the quantitative consequences for populations across gradients in the rates and quality of resource inputs. In our introduction to this special issue, we describe at least four potential models that describe functional relationships between subsidy input rates and consumer responses, most of them asymptotic. Here we aim to advance our quantitative understanding of how subsidy inputs influence recipient consumers and their communities. In the papers following, fish were either the recipient consumers or the subsidy as carcasses of anadromous species. Advancing general, predictive models will enable us to further consider what other factors are potentially co-limiting (e.g., nutrients, other population interactions, physical habitat, etc.) and better integrate resource subsidies into consumer–resource, biophysical dynamics models.

Photoswitchable red fluorescent protein with a large Stokes shift

PubMed Central

Piatkevich, Kiryl D.; English, Brian P.; Malashkevich, Vladimir N.; Xiao, Hui; Almo, Steven C.; Singer, Robert H.; Verkhusha, Vladislav V.

2014-01-01

SUMMARY Subclass of fluorescent proteins, large Stokes shift fluorescent proteins, is characterized by their increased spread between the excitation and emission maxima. Here we report a photoswitchable variant of a red fluorescent protein with a large Stokes shift, PSLSSmKate, which initially exhibits excitation/emission at 445/622 nm, but irradiation with violet light photoswitches PSLSSmKate into a common red form with excitation/emission at 573/621 nm. We characterize spectral, photophysical and biochemical properties of PSLSSmKate in vitro and in mammalian cells, and determine its crystal structure in the large Stokes shift form. Mass-spectrometry, mutagenesis and spectroscopic analysis of PSLSSmKate allow us to propose molecular mechanisms for the large Stokes shift, pH dependence and light-induced chromophore transformation. We demonstrate applicability of PSLSSmKate to superresolution PALM microscopy and protein dynamics in live cells. Given its promising properties, we expect that PSLSSmKate-like phenotype will be further used for photoactivatable imaging and tracking multiple populations of intracellular objects. PMID:25242289

Injury prevention and other international public health initiatives.

PubMed

Razzak, Junaid A; Sasser, Scott M; Kellermann, Arthur L

2005-02-01

Injuries, whether caused by unintentional or intentional events, area significant public health problem. The burden of injury is greatest in low-and middle-income countries and among individuals of low socioeconomic status living in high-income countries. Most of these injuries are prevent-able. Emergency physicians can play an important role in reducing the global burden of injuries by providing expert care and by identifying, implementing, and evaluating population-based countermeasures to prevent and control injuries. The strategy used in a particular country depends in large part on the nature of the local problem, the concerns of the population, the availability of resources, and competing demands. Even simple countermeasures may have a big impact in reducing the global burden of death and disability due to injury.

Awareness and attitudes towards organ donation and transplantation among the asian population. A preliminary survey in Luton, UK.

PubMed

Darr, A; Randhawa, G

1999-01-01

Currently the demand for transplant organs, particularly kidneys, far outstrips the supply in the UK. This problem is particularly severe for the Asian population, which has been shown to have a disproportionately large representation on kidney-transplant waiting lists in some regions of the UK. The situation is clear: there is an urgent need to address the number of Asians requiring a kidney transplant, otherwise the human and economic costs will be very high. An exploratory qualitative study was therefore undertaken with the aim of assessing current awareness of organ donation and transplantation and to explore attitudes towards these issues in a cross section of the Asian population in Luton. It was found that nearly half of the respondents in this survey did not know what a donor card was used for, and approximately half of these had never seen one; only 6 of the 64 people interviewed had heard of the National Donor Register. Of the three people who carried a donor card, two had an immediate family member who had received a transplant. This suggests that media campaigns aimed at attracting donors from the Asian population have had limited success thus far. It appears that the vast majority of the Asian population is at the initial stage of the process of making a decision about donating their organs, that of simply knowing that transplantation takes place. Very little debate of pertinent issues seems to have taken place, which is essential for reaching a decision on whether or not to donate an organ. The study should be seen as exploratory but is nonetheless an important initial step towards the establishment of a greater knowledge and understanding of the issues affecting the low donation rate in the Asian population.

Rapid divergence of mussel populations despite incomplete barriers to dispersal.

PubMed

Maas, Diede L; Prost, Stefan; Bi, Ke; Smith, Lydia L; Armstrong, Ellie E; Aji, Ludi P; Toha, Abdul Hamid A; Gillespie, Rosemary G; Becking, Leontine E

2018-04-01

Striking genetic structure among marine populations at small spatial scales is becoming evident with extensive molecular studies. Such observations suggest isolation at small scales may play an important role in forming patterns of genetic diversity within species. Isolation-by-distance, isolation-by-environment and historical priority effects are umbrella terms for a suite of processes that underlie genetic structure, but their relative importance at different spatial and temporal scales remains elusive. Here, we use marine lakes in Indonesia to assess genetic structure and assess the relative roles of the processes in shaping genetic differentiation in populations of a bivalve mussel (Brachidontes sp.). Marine lakes are landlocked waterbodies of similar age (6,000-10,000 years), but with heterogeneous environments and varying degrees of connection to the sea. Using a population genomic approach (double-digest restriction-site-associated DNA sequencing), we show strong genetic structuring across populations (range F ST : 0.07-0.24) and find limited gene flow through admixture plots. At large spatial scales (>1,400 km), a clear isolation-by-distance pattern was detected. At smaller spatial scales (<200 km), this pattern is maintained, but accompanied by an association of genetic divergence with degree of connection. We hypothesize that (incomplete) dispersal barriers can cause initial isolation, allowing priority effects to give the numerical advantage necessary to initiate strong genetic structure. Priority effects may be strengthened by local adaptation, which the data may corroborate by showing a high correlation between mussel genotypes and temperature. Our study indicates an often-neglected role of (evolution-mediated) priority effects in shaping population divergence. © 2018 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.

A high-resolution genetic signature of demographic and spatial expansion in epizootic rabies virus

PubMed Central

Biek, Roman; Henderson, J. Caroline; Waller, Lance A.; Rupprecht, Charles E.; Real, Leslie A.

2007-01-01

Emerging pathogens potentially undergo rapid evolution while expanding in population size and geographic range during the course of invasion, yet it is generally difficult to demonstrate how these processes interact. Our analysis of a 30-yr data set covering a large-scale rabies virus outbreak among North American raccoons reveals the long lasting effect of the initial infection wave in determining how viral populations are genetically structured in space. We further find that coalescent-based estimates derived from the genetic data yielded an amazingly accurate reconstruction of the known spatial and demographic dynamics of the virus over time. Our study demonstrates the combined evolutionary and population dynamic processes characterizing the spread of pathogen after its introduction into a fully susceptible host population. Furthermore, the results provide important insights regarding the spatial scale of rabies persistence and validate the use of coalescent approaches for uncovering even relatively complex population histories. Such approaches will be of increasing relevance for understanding the epidemiology of emerging zoonotic diseases in a landscape context. PMID:17470818

A thought on the integration of poverty relief with family planning.

PubMed

Yang, K

1997-01-01

This article discusses the relationship between population growth and poverty in China, the issue of overpopulation in poor areas, and the need for programs that integrate population control with economic development. The number of Chinese living in poverty declined from about 250 million in 1978 to 80 million in 1993. In March 1994, the government initiated a poverty relief program that aimed to eliminate all poverty by 2001. By 1995, the number of poor declined to 65 million. The causes of poverty are numerous, but include overpopulation. Over the decades, demographic trends in poor areas reveal higher fertility, lower mortality, and higher growth. Poverty appears to be concentrated in 18 provinces and autonomous regions. Poor areas have higher rates of early marriage, early childbirth, and multiple children. Poor areas also have higher rates of disabilities and disease and lower levels of education. Poor areas have double the national percentage of illiterates. Many people living in poor areas are disadvantaged by poor transportation, remote locations, backward production methods, and a lack of a social security system. Scientific knowledge about contraception and quality child care are difficult to diffuse in poor areas. The size of the population denominator directly affects per capita income and per capita grain production. Increases in population put pressure on investment resources for production and development. A larger work force adds to the problem of unemployment. A large population size puts pressure on arable land. Poor areas need a better educated population. Sustainable development requires fertility decline. Integrated family planning programs popularize slogans such as "stabilize grain yield, increase income, and control population growth." Integrated programs have had variable success. Countermeasures must be taken to prevent the association of large families with wealth. Leadership is essential.

Weighted social networks for a large scale artificial society

NASA Astrophysics Data System (ADS)

Fan, Zong Chen; Duan, Wei; Zhang, Peng; Qiu, Xiao Gang

2016-12-01

The method of artificial society has provided a powerful way to study and explain how individual behaviors at micro level give rise to the emergence of global social phenomenon. It also creates the need for an appropriate representation of social structure which usually has a significant influence on human behaviors. It has been widely acknowledged that social networks are the main paradigm to describe social structure and reflect social relationships within a population. To generate social networks for a population of interest, considering physical distance and social distance among people, we propose a generation model of social networks for a large-scale artificial society based on human choice behavior theory under the principle of random utility maximization. As a premise, we first build an artificial society through constructing a synthetic population with a series of attributes in line with the statistical (census) data for Beijing. Then the generation model is applied to assign social relationships to each individual in the synthetic population. Compared with previous empirical findings, the results show that our model can reproduce the general characteristics of social networks, such as high clustering coefficient, significant community structure and small-world property. Our model can also be extended to a larger social micro-simulation as an input initial. It will facilitate to research and predict some social phenomenon or issues, for example, epidemic transition and rumor spreading.

Combination of graph heuristics in producing initial solution of curriculum based course timetabling problem

NASA Astrophysics Data System (ADS)

Wahid, Juliana; Hussin, Naimah Mohd

2016-08-01

The construction of population of initial solution is a crucial task in population-based metaheuristic approach for solving curriculum-based university course timetabling problem because it can affect the convergence speed and also the quality of the final solution. This paper presents an exploration on combination of graph heuristics in construction approach in curriculum based course timetabling problem to produce a population of initial solutions. The graph heuristics were set as single and combination of two heuristics. In addition, several ways of assigning courses into room and timeslot are implemented. All settings of heuristics are then tested on the same curriculum based course timetabling problem instances and are compared with each other in terms of number of population produced. The result shows that combination of saturation degree followed by largest degree heuristic produce the highest number of population of initial solutions. The results from this study can be used in the improvement phase of algorithm that uses population of initial solutions.

Propagation of solutions to the Fisher-KPP equation with slowly decaying initial data

NASA Astrophysics Data System (ADS)

Henderson, Christopher

2016-10-01

The Fisher-KPP equation is a model for population dynamics that has generated a huge amount of interest since its introduction in 1937. The speed with which a population spreads has been computed quite precisely when the initial data, u 0, decays exponentially. More recently, though, the case when the initial data decays more slowly has been studied. In Hamel F and Roques L (2010 J. Differ. Equ. 249 1726-45), the authors show that the level sets of height of m of u move super-linearly and may be bounded above and below by expressions of the form u0-1≤ft({{c}m}{{\\text{e}}-t}\\right) when u 0 decays algebraically of a small enough order. The constants c m for the upper and lower bounds that they obtain are not explicit and do not match. In this paper, we improve their precision for a broader class of initial data and for a broader class of equations. In particular, our approach yields the explicit highest order term in the location of the level sets, which in the most basic setting is given by u0-1≤ft(m{{\\text{e}}-t}/(1-m)\\right) as long as u 0 decays slower than {{\\text{e}}-\\sqrt{x}} . We generalize this to the previously unstudied setting when the nonlinearity is periodic in space. In addition, for large times, we characterize the profile of the solution in terms of a generalized logistic equation.

Rethinking "normal": The role of stochasticity in the phenology of a synchronously breeding seabird.

PubMed

Youngflesh, Casey; Jenouvrier, Stephanie; Hinke, Jefferson T; DuBois, Lauren; St Leger, Judy; Trivelpiece, Wayne Z; Trivelpiece, Susan G; Lynch, Heather J

2018-05-01

Phenological changes have been observed in a variety of systems over the past century. There is concern that, as a consequence, ecological interactions are becoming increasingly mismatched in time, with negative consequences for ecological function. Significant spatial heterogeneity (inter-site) and temporal variability (inter-annual) can make it difficult to separate intrinsic, extrinsic and stochastic drivers of phenological variability. The goal of this study was to understand the timing and variability in breeding phenology of Adélie penguins under fixed environmental conditions and to use those data to identify a "null model" appropriate for disentangling the sources of variation in wild populations. Data on clutch initiation were collected from both wild and captive populations of Adélie penguins. Clutch initiation in the captive population was modelled as a function of year, individual and age to better understand phenological patterns observed in the wild population. Captive populations displayed as much inter-annual variability in breeding phenology as wild populations, suggesting that variability in breeding phenology is the norm and thus may be an unreliable indicator of environmental forcing. The distribution of clutch initiation dates was found to be moderately asymmetric (right skewed) both in the wild and in captivity, consistent with the pattern expected under social facilitation. The role of stochasticity in phenological processes has heretofore been largely ignored. However, these results suggest that inter-annual variability in breeding phenology can arise independent of any environmental or demographic drivers and that synchronous breeding can enhance inherent stochasticity. This complicates efforts to relate phenological variation to environmental variability in the wild. Accordingly, we must be careful to consider random forcing in phenological processes, lest we fit models to data dominated by random noise. This is particularly true for colonial species where breeding synchrony may outweigh each individual's effort to time breeding with optimal environmental conditions. Our study highlights the importance of identifying appropriate null models for studying phenology. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Towards a population synthesis model of objects formed by self-gravitating disc fragmentation and tidal downsizing

NASA Astrophysics Data System (ADS)

Forgan, Duncan; Rice, Ken

2013-07-01

Recently, the gravitational instability (GI) model of giant planet and brown dwarf formation has been revisited and recast into what is often referred to as the `tidal downsizing' hypothesis. The fragmentation of self-gravitating protostellar discs into gravitationally bound embryos - with masses of a few to tens of Jupiter masses, at semimajor axes above 30-40 au - is followed by a combination of grain sedimentation inside the embryo, radial migration towards the central star and tidal disruption of the embryo's upper layers. The properties of the resultant object depends sensitively on the time-scales upon which each process occurs. Therefore, GI followed by tidal downsizing can theoretically produce objects spanning a large mass range, from terrestrial planets to giant planets and brown dwarfs. Whether such objects can be formed in practice, and what proportions of the observed population they would represent, requires a more involved statistical analysis. We present a simple population synthesis model of star and planet formation via GI and tidal downsizing. We couple a semi-analytic model of protostellar disc evolution to analytic calculations of fragmentation, initial embryo mass, grain growth and sedimentation, embryo migration and tidal disruption. While there are key pieces of physics yet to be incorporated, it represents a first step towards a mature statistical model of GI and tidal downsizing as a mode of star and planet formation. We show results from four runs of the population synthesis model, varying the opacity law and the strength of migration, as well as investigating the effect of disc truncation during the fragmentation process. We find that a large fraction of disc fragments are completely destroyed by tidal disruption (typically 40 per cent of the initial population). The tidal downsizing process tends to prohibit low-mass embryos reaching small semimajor axis. The majority of surviving objects are brown dwarfs without solid cores of any kind. Around 40 per cent of surviving objects form solid cores of the order of 5-10 M⊕, and of this group a few do migrate to distances amenable to current exoplanet observations. Over a million disc fragments were simulated in this work, and only one resulted in the formation of a terrestrial planet (i.e. with a core mass of a few Earth masses and no gaseous envelope). These early results suggest that GI followed by tidal downsizing is not the principal mode of planet formation, but remains an excellent means of forming gas giant planets, brown dwarfs and low-mass stars at large semimajor axes.

Creating targeted initial populations for genetic product searches in heterogeneous markets

NASA Astrophysics Data System (ADS)

Foster, Garrett; Turner, Callaway; Ferguson, Scott; Donndelinger, Joseph

2014-12-01

Genetic searches often use randomly generated initial populations to maximize diversity and enable a thorough sampling of the design space. While many of these initial configurations perform poorly, the trade-off between population diversity and solution quality is typically acceptable for small-scale problems. Navigating complex design spaces, however, often requires computationally intelligent approaches that improve solution quality. This article draws on research advances in market-based product design and heuristic optimization to strategically construct 'targeted' initial populations. Targeted initial designs are created using respondent-level part-worths estimated from discrete choice models. These designs are then integrated into a traditional genetic search. Two case study problems of differing complexity are presented to illustrate the benefits of this approach. In both problems, targeted populations lead to computational savings and product configurations with improved market share of preferences. Future research efforts to tailor this approach and extend it towards multiple objectives are also discussed.

Risk and Prognosis of Bacteremia and Fungemia Among Peritoneal Dialysis Patients: A Population-Based Cohort Study.

PubMed

Dalgaard, Lars Skov; Nørgaard, Mette; Povlsen, Johan Vestergaard; Jespersen, Bente; Jensen-Fangel, Søren; Ellermann-Eriksen, Svend; Østergaard, Lars; Schønheyder, Henrik Carl; Søgaard, Ole Schmeltz

♦ BACKGROUND: The incidence of bacteremia and fungemia (BAF) is largely unknown in end-stage renal disease (ESRD) patients initiating peritoneal dialysis (PD). ♦ OBJECTIVE: The main objective was to estimate and compare incidence rates of first episodes of BAF in incident PD patients and a comparison cohort. A secondary objective was to compare causative agents and 30-day post-BAF mortality between PD patients and the comparison cohort. ♦ METHODS: Design: Observational cohort study. Central and North Denmark regions. patients who initiated PD during 1995 - 2010. For each patient we sampled up to 10 controls from the general population matched on age, sex, and municipality. ♦ MAIN OUTCOME: Data on positive blood cultures were retrieved from electronic microbiology databases covering the 2 regions. We calculated incidence rates (IRs) of first-time BAF for PD patients and population controls. Incidence-rate ratios (IRRs) were calculated to compare these rates. Thirty-day mortality was estimated by Kaplan-Meier analysis. ♦ RESULTS: Among 1,024 PD patients and 10,215 population controls, we identified 75 and 282 episodes of BAF, respectively. Incidence rates of BAF were 4.7 (95% confidence interval [CI], 3.8 - 5.9) per 100 person-years of follow-up (PYFU) in PD patients and 0.5 (95% CI, 0.4 - 0.5) per 100 PYFU in population controls (IRR = 10.4; 95% CI, 8.1 - 13.5). In PD patients, the most frequent microorganisms were Escherichia coli (18.7%) and Staphylococcus aureus (13.3%). Escherichia coli (27.3%) also ranked first among population controls. Thirty-day mortality following BAF was 20.8% (95% CI, 12.6 - 31.0) and 20.7% (95% CI, 16.3 - 25.9) among PD patients and population controls, respectively. ♦ CONCLUSIONS: Peritoneal dialysis patients are at markedly higher risk of BAF than population controls. Causative agents and the 30-day post-BAF mortality were similar in the 2 cohorts. Copyright © 2016 International Society for Peritoneal Dialysis.

Effects of trophy hunting on lion and leopard populations in Tanzania.

PubMed

Packer, C; Brink, H; Kissui, B M; Maliti, H; Kushnir, H; Caro, T

2011-02-01

Tanzania holds most of the remaining large populations of African lions (Panthera leo) and has extensive areas of leopard habitat (Panthera pardus), and both species are subjected to sizable harvests by sport hunters. As a first step toward establishing sustainable management strategies, we analyzed harvest trends for lions and leopards across Tanzania's 300,000 km(2) of hunting blocks. We summarize lion population trends in protected areas where lion abundance has been directly measured and data on the frequency of lion attacks on humans in high-conflict agricultural areas. We place these findings in context of the rapidly growing human population in rural Tanzania and the concomitant effects of habitat loss, human-wildlife conflict, and cultural practices. Lion harvests declined by 50% across Tanzania between 1996 and 2008, and hunting areas with the highest initial harvests suffered the steepest declines. Although each part of the country is subject to some form of anthropogenic impact from local people, the intensity of trophy hunting was the only significant factor in a statistical analysis of lion harvest trends. Although leopard harvests were more stable, regions outside the Selous Game Reserve with the highest initial leopard harvests again showed the steepest declines. Our quantitative analyses suggest that annual hunting quotas be limited to 0.5 lions and 1.0 leopard/1000 km(2) of hunting area, except hunting blocks in the Selous Game Reserve, where harvests should be limited to 1.0 lion and 3.0 leopards/1000 km(2) . ©2010 Society for Conservation Biology.

Restoration of bighorn sheep metapopulations in and near 15 national parks: Conservation of a severely fragmented species; Volume I, Planning, problem definition, findings, and restoration

USGS Publications Warehouse

Singer, Francis J.; Gudorf, Michelle A.

1999-01-01

Bighorn sheep (Ovis canadensis) were historically a ubiquitous species. Prior to the arrival of Europeans, they were seemingly widespread in nearly all steep habitats in the mountains, foothills, river breaks, and prairie badlands of the western United States. However, since catastrophic declines in the late 1800s and early 1900s, most extant populations have existed as small, isolated groups in a highly fragmented distribution. Stochastic events such as seasonal weather change or population fluctuations render these small populations more prone to extirpation than larger populations. Three different subspecies of bighorn sheep were eliminated from 14 of 18 National Park System (NPS) units in the 6-state Intermountain Region of the western United States (Singer 1994). In 1990, when this restoration was initiated, only 4 (18%) of 22 discrete park populations or metapopulations were considered large enough (300-500 animals) to be secure for long-term management. Five (23%) other populations numbered 100-299 animals and 3 (14%) populations numbered 75-99 animals. But, the remaining 10 populations (45%) were either extirpated (n = 2), remnant populations (n = 5, populations of 7-10 animals), or vulnerable to extirpation (n = 3, populations of less than 50 animals). Restoration prior to 1991-96 was largely completed in one NPS unit, but was incomplete in the remaining units. Most bighorn sheep are not federally listed as endangered or threatened species, although the California peninsular population of desert bighorn sheep was recently listed as endangered. The bighorn sheep is a rare or uncommon species that is declining in many parts of its range but is abundant in other areas and still relatively easy to study and manage. The Secretary of the Department of the Interior, Bruce Babbitt, directed the Biological Resources Division of the U.S. Geological Survey in 1993 (when this agency was still the National Biological Service) to research and recover species that were declining to avoid expensive and controversial federal listing. Because the capture and moving of the species are still relatively uncomplicated and because some source stocks are available, aggressive restoration in 15 National Park System units in the former Rocky Mountain Region was recommended in 1990. This report details the 7-year restoration of bighorn sheep to all currently suitable historic habitats in the national parks of the former Rocky Mountain Region (now the Intermountain and Midwest regions of the National Park Service). The purpose of the first phase of the restoration during 1991-93 was to conduct research and population surveys and to formulate the restoration plans. The purpose of the second phase of the initiative during 1994-97 was to conduct GIS-based habitat and biological assessments of prospective restoration sites, write restoration plans, and restore and monitor the released bighorn sheep.

Modeling responses of large-river fish populations to global climate change through downscaling and incorporation of predictive uncertainty

USGS Publications Warehouse

Wildhaber, Mark L.; Wikle, Christopher K.; Anderson, Christopher J.; Franz, Kristie J.; Moran, Edward H.; Dey, Rima; Mader, Helmut; Kraml, Julia

2012-01-01

Climate change operates over a broad range of spatial and temporal scales. Understanding its effects on ecosystems requires multi-scale models. For understanding effects on fish populations of riverine ecosystems, climate predicted by coarse-resolution Global Climate Models must be downscaled to Regional Climate Models to watersheds to river hydrology to population response. An additional challenge is quantifying sources of uncertainty given the highly nonlinear nature of interactions between climate variables and community level processes. We present a modeling approach for understanding and accomodating uncertainty by applying multi-scale climate models and a hierarchical Bayesian modeling framework to Midwest fish population dynamics and by linking models for system components together by formal rules of probability. The proposed hierarchical modeling approach will account for sources of uncertainty in forecasts of community or population response. The goal is to evaluate the potential distributional changes in an ecological system, given distributional changes implied by a series of linked climate and system models under various emissions/use scenarios. This understanding will aid evaluation of management options for coping with global climate change. In our initial analyses, we found that predicted pallid sturgeon population responses were dependent on the climate scenario considered.

Nationwide Genomic Study in Denmark Reveals Remarkable Population Homogeneity

PubMed Central

Athanasiadis, Georgios; Cheng, Jade Y.; Vilhjálmsson, Bjarni J.; Jørgensen, Frank G.; Als, Thomas D.; Le Hellard, Stephanie; Espeseth, Thomas; Sullivan, Patrick F.; Hultman, Christina M.; Kjærgaard, Peter C.; Schierup, Mikkel H.; Mailund, Thomas

2016-01-01

Denmark has played a substantial role in the history of Northern Europe. Through a nationwide scientific outreach initiative, we collected genetic and anthropometrical data from ∼800 high school students and used them to elucidate the genetic makeup of the Danish population, as well as to assess polygenic predictions of phenotypic traits in adolescents. We observed remarkable homogeneity across different geographic regions, although we could still detect weak signals of genetic structure reflecting the history of the country. Denmark presented genomic affinity with primarily neighboring countries with overall resemblance of decreasing weight from Britain, Sweden, Norway, Germany, and France. A Polish admixture signal was detected in Zealand and Funen, and our date estimates coincided with historical evidence of Wend settlements in the south of Denmark. We also observed considerably diverse demographic histories among Scandinavian countries, with Denmark having the smallest current effective population size compared to Norway and Sweden. Finally, we found that polygenic prediction of self-reported adolescent height in the population was remarkably accurate (R2 = 0.639 ± 0.015). The high homogeneity of the Danish population could render population structure a lesser concern for the upcoming large-scale gene-mapping studies in the country. PMID:27535931

Pair and triplet approximation of a spatial lattice population model with multiscale dispersal using Markov chains for estimating spatial autocorrelation.

PubMed

Hiebeler, David E; Millett, Nicholas E

2011-06-21

We investigate a spatial lattice model of a population employing dispersal to nearest and second-nearest neighbors, as well as long-distance dispersal across the landscape. The model is studied via stochastic spatial simulations, ordinary pair approximation, and triplet approximation. The latter method, which uses the probabilities of state configurations of contiguous blocks of three sites as its state variables, is demonstrated to be greatly superior to pair approximations for estimating spatial correlation information at various scales. Correlations between pairs of sites separated by arbitrary distances are estimated by constructing spatial Markov processes using the information from both approximations. These correlations demonstrate why pair approximation misses basic qualitative features of the model, such as decreasing population density as a large proportion of offspring are dropped on second-nearest neighbors, and why triplet approximation is able to include them. Analytical and numerical results show that, excluding long-distance dispersal, the initial growth rate of an invading population is maximized and the equilibrium population density is also roughly maximized when the population spreads its offspring evenly over nearest and second-nearest neighboring sites. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of Statin Use on Acute Kidney Injury Risk Following Coronary Artery Bypass Grafting

PubMed Central

Layton, J. Bradley; Kshirsagar, Abhijit V.; Simpson, Ross J.; Pate, Virginia; Funk, Michele Jonsson; Sturmer, Til; Brookhart, M. Alan

2013-01-01

Acute kidney injury (AKI) is a serious complication of cardiovascular surgery. While some non-experimental studies suggest statin use may reduce post-surgical AKI, methodological differences in study designs leave uncertainty regarding the reality or magnitude of the effect. We estimated the effect of pre-operative statin initiation on post-coronary artery bypass graft (CABG) AKI using an epidemiologic approach more closely simulating a randomized controlled trial in a large CABG patient population. We utilized healthcare claims from large, employer-based and Medicare insurance databases for the years 2000 – 2010. To minimize healthy user bias, we identified patients undergoing non-emergency CABG who either newly initiated a statin within 20 days prior to surgery or were unexposed for 200+ days prior to CABG. AKI was identified within 15 days following CABG. We calculated multivariable adjusted risk ratios (RR) and 95% confidence intervals (CI) with Poisson regression. Analyses were repeated using propensity score methods adjusted for clinical and healthcare utilization variables. We identified 17,077 CABG patients. Post-CABG AKI developed in 3.4% of statin initiators and 6.2% of non-initiators. After adjustment, we observed a protective effect of statin initiation on AKI (RR = 0.78, 95% CI 0.63, 0.96). This effect differed by age: ≥65 years, RR=0.91 (95% CI: 0.68, 1.20); <65 years, RR=0.62 (95% CI: 0.45, 0.86), although AKI was more common in the older age group (7.7 vs. 4.0%). In conclusion, statin initiation immediately prior to CABG may modestly reduce the risk of post-operative AKI, particularly in younger CABG patients. PMID:23273532

Influence of Algae Age and Population on the Response to TiO₂ Nanoparticles.

PubMed

Metzler, David M; Erdem, Ayca; Huang, Chin Pao

2018-03-25

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO₂ NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3-4.2 × 10⁶ cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO₂ NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae.

Influence of Algae Age and Population on the Response to TiO2 Nanoparticles

PubMed Central

Metzler, David M.; Erdem, Ayca; Huang, Chin Pao

2018-01-01

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO2 NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3−4.2 × 106 cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO2 NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae. PMID:29587381

The initial tolerance to sub-lethal Cd exposure is the same among ten naïve pond populations of Daphnia magna, but their micro-evolutionary potential to develop resistance is very different.

PubMed

Messiaen, Marlies; Janssen, Colin Roger; De Meester, Luc; De Schamphelaere, Karel André Clara

2013-11-15

Genetic variation complicates predictions of both the initial tolerance and the long-term (micro-evolutionary) response of natural Daphnia populations to chemical stressors from results of standard single-clone laboratory ecotoxicity tests. In order to investigate possible solutions to this problem, we aimed to compare the initial sub-lethal tolerance to Cd of 10 naïve natural pond populations of Daphnia magna as well as their evolutionary potential to develop increased resistance. We did so by measuring reproductive performance of 120 clones, i.e. 12 clones hatched from the recent dormant egg bank of each of 10 populations, both in absence (Cd-free control) and presence of 4.4 μg Cd/L. We show that the initial tolerance, defined as the reproductive performance of individuals of the first generation exposed to Cd relative to that in a Cd-free control was not significantly different among the 10 studied pond populations and averaged 0.82 ± 0.04 over these populations. Moreover, these populations' initial tolerances were also not significantly different from the mean initial tolerance of 0.87 ± 0.08 at 4.0 μg Cd/L measured for a group of 7 often-used laboratory clones, collected from a range of European ecotoxicity testing laboratories. This indicates that the initial response of naïve natural pond populations to sub-lethal Cd can be relatively accurately predicted from ecotoxicity test data from only a handful of laboratory clones. We then used estimates of broad-sense heritability of Cd tolerance (H(2)) - based on the same dataset - as a proxy of these populations' capacities to evolutionarily respond to Cd in terms of the development of increased resistance, which is here defined as the increase with time of the frequency of clones with a higher Cd tolerance in the population (accompanied with an increase of mean Cd-tolerance of the population above the initial tolerance). We show that the populations' estimated H(2) values of Cd-tolerance cover almost the entire theoretically possible range, ranging from not significantly different from zero (for five populations) to between 0.48 and 0.81 (for the five other populations). This indicates that, unlike the initial tolerance to Cd, the (long-term) micro-evolutionary response to Cd may be very different among natural pond populations. Therefore, we conclude that it may be very difficult to predict the long-term response of an unstudied population to chemical stress from tolerance data on a sample of other populations. It is therefore suggested that new methods for forecasting long-term responses should be explored, such as the development of predictive models based on the combination of population-genomic and tolerance time-series data. Copyright © 2013 Elsevier B.V. All rights reserved.

Predictive value of autoantibody testing for validating self-reported diagnoses of rheumatoid arthritis in the Women's Health Initiative.

PubMed

Walitt, Brian; Mackey, Rachel; Kuller, Lewis; Deane, Kevin D; Robinson, William; Holers, V Michael; Chang, Yue-Fang; Moreland, Larry

2013-05-01

Rheumatoid arthritis (RA) research using large databases is limited by insufficient case validity. Of 161,808 postmenopausal women in the Women's Health Initiative, 15,691 (10.2%) reported having RA, far higher than the expected 1% population prevalence. Since chart review for confirmation of an RA diagnosis is impractical in large cohort studies, the current study (2009-2011) tested the ability of baseline serum measurements of rheumatoid factor and anti-cyclic citrullinated peptide antibodies, second-generation assay (anti-CCP2), to identify physician-validated RA among the chart-review study participants with self-reported RA (n = 286). Anti-CCP2 positivity had the highest positive predictive value (PPV) (80.0%), and rheumatoid factor positivity the lowest (44.6%). Together, use of disease-modifying antirheumatic drugs and anti-CCP2 positivity increased PPV to 100% but excluded all seronegative cases (approximately 15% of all RA cases). Case definitions inclusive of seronegative cases had PPVs between 59.6% and 63.6%. False-negative results were minimized in these test definitions, as evidenced by negative predictive values of approximately 90%. Serological measurements, particularly measurement of anti-CCP2, improved the test characteristics of RA case definitions in the Women's Health Initiative.

Making a stand: five centuries of population growth in colonizing populations of Pinus ponderosa.

PubMed

Lesser, Mark R; Jackson, Stephen T

2012-05-01

The processes underlying the development of new populations are important for understanding how species colonize new territory and form viable long-term populations. Life-history-mediated processes such as Allee effects and dispersal capability may interact with climate variability and site-specific factors to govern population success and failure over extended time frames. We studied four disjunct populations of ponderosa pine in the Bighorn Basin of north-central Wyoming to examine population growth spanning more than five centuries. The study populations are separated from continuous ponderosa pine forest by distances ranging from 15 to >100 km. Strong evidence indicates that the initial colonizing individuals are still present, yielding a nearly complete record of population history. All trees in each population were aged using dendroecological techniques. The populations were all founded between 1530 and 1655 cal yr CE. All show logistic growth patterns, with initial exponential growth followed by a slowing during the mid to late 20th century. Initial population growth was slower than expectations from a logistic regression model at all four populations, but increased during the mid-18th century. Initial lags in population growth may have been due to strong Allee effects. A combination of overcoming Allee effects and a transition to favorable climate conditions may have facilitated a mid-18th century pulse in population growth rate.

Uptake of Tailored Text Message Smoking Cessation Support in Pregnancy When Advertised on the Internet (MiQuit): Observational Study.

PubMed

Emery, Joanne L; Coleman, Tim; Sutton, Stephen; Cooper, Sue; Leonardi-Bee, Jo; Jones, Matthew; Naughton, Felix

2018-04-19

Smoking in pregnancy is a major public health concern. Pregnant smokers are particularly difficult to reach, with low uptake of support options and few effective interventions. Text message-based self-help is a promising, low-cost intervention for this population, but its real-world uptake is largely unknown. The objective of this study was to explore the uptake and cost-effectiveness of a tailored, theory-guided, text message intervention for pregnant smokers ("MiQuit") when advertised on the internet. Links to a website providing MiQuit initiation information (texting a short code) were advertised on a cost-per-click basis on 2 websites (Google Search and Facebook; £1000 budget each) and free of charge within smoking-in-pregnancy webpages on 2 noncommercial websites (National Childbirth Trust and NHS Choices). Daily budgets were capped to allow the Google and Facebook adverts to run for 1 and 3 months, respectively. We recorded the number of times adverts were shown and clicked on, the number of MiQuit initiations, the characteristics of those initiating MiQuit, and whether support was discontinued prematurely. For the commercial adverts, we calculated the cost per initiation and, using quit rates obtained from an earlier clinical trial, estimated the cost per additional quitter. With equal capped budgets, there were 812 and 1889 advert clicks to the MiQuit website from Google (search-based) and Facebook (banner) adverts, respectively. MiQuit was initiated by 5.2% (42/812) of those clicking via Google (95% CI 3.9%-6.9%) and 2.22% (42/1889) of those clicking via Facebook (95% CI 1.65%-2.99%). Adverts on noncommercial webpages generated 53 clicks over 6 months, with 9 initiations (9/53, 17%; 95% CI 9%-30%). For the commercial websites combined, mean cost per initiation was £24.73; estimated cost per additional quitter, including text delivery costs, was £735.86 (95% CI £227.66-£5223.93). Those initiating MiQuit via Google were typically very early in pregnancy (median gestation 5 weeks, interquartile range 10 weeks); those initiating via Facebook were distributed more evenly across pregnancy (median gestation 16 weeks, interquartile range 14 weeks). Commercial online adverts are a feasible, likely cost-effective method for engaging pregnant smokers in digital cessation support and may generate uptake at a faster rate than noncommercial websites. As a strategy for implementing MiQuit, online advertising has large reach potential and can offer support to a hard-to-reach population of smokers. ©Joanne L Emery, Tim Coleman, Stephen Sutton, Sue Cooper, Jo Leonardi-Bee, Matthew Jones, Felix Naughton. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 19.04.2018.

Uptake of Tailored Text Message Smoking Cessation Support in Pregnancy When Advertised on the Internet (MiQuit): Observational Study

PubMed Central

Coleman, Tim; Sutton, Stephen; Cooper, Sue; Leonardi-Bee, Jo; Jones, Matthew; Naughton, Felix

2018-01-01

Background Smoking in pregnancy is a major public health concern. Pregnant smokers are particularly difficult to reach, with low uptake of support options and few effective interventions. Text message–based self-help is a promising, low-cost intervention for this population, but its real-world uptake is largely unknown. Objective The objective of this study was to explore the uptake and cost-effectiveness of a tailored, theory-guided, text message intervention for pregnant smokers (“MiQuit”) when advertised on the internet. Methods Links to a website providing MiQuit initiation information (texting a short code) were advertised on a cost-per-click basis on 2 websites (Google Search and Facebook; £1000 budget each) and free of charge within smoking-in-pregnancy webpages on 2 noncommercial websites (National Childbirth Trust and NHS Choices). Daily budgets were capped to allow the Google and Facebook adverts to run for 1 and 3 months, respectively. We recorded the number of times adverts were shown and clicked on, the number of MiQuit initiations, the characteristics of those initiating MiQuit, and whether support was discontinued prematurely. For the commercial adverts, we calculated the cost per initiation and, using quit rates obtained from an earlier clinical trial, estimated the cost per additional quitter. Results With equal capped budgets, there were 812 and 1889 advert clicks to the MiQuit website from Google (search-based) and Facebook (banner) adverts, respectively. MiQuit was initiated by 5.2% (42/812) of those clicking via Google (95% CI 3.9%-6.9%) and 2.22% (42/1889) of those clicking via Facebook (95% CI 1.65%-2.99%). Adverts on noncommercial webpages generated 53 clicks over 6 months, with 9 initiations (9/53, 17%; 95% CI 9%-30%). For the commercial websites combined, mean cost per initiation was £24.73; estimated cost per additional quitter, including text delivery costs, was £735.86 (95% CI £227.66-£5223.93). Those initiating MiQuit via Google were typically very early in pregnancy (median gestation 5 weeks, interquartile range 10 weeks); those initiating via Facebook were distributed more evenly across pregnancy (median gestation 16 weeks, interquartile range 14 weeks). Conclusions Commercial online adverts are a feasible, likely cost-effective method for engaging pregnant smokers in digital cessation support and may generate uptake at a faster rate than noncommercial websites. As a strategy for implementing MiQuit, online advertising has large reach potential and can offer support to a hard-to-reach population of smokers. PMID:29674308

CD30 expression in follicular lymphoma.

PubMed

Gardner, L J; Polski, J M; Evans, H L; Perkins, S L; Dunphy, C H

2001-08-01

CD30(+) anaplastic large cell lymphomas were originally described as being of T-cell, null cell, and B-cell origin. CD30, however, is not a specific marker of anaplastic large cell lymphoma and has been found to be expressed in reactive as well as neoplastic populations as a probable activation marker. In addition, CD30(+) cells have also been described in both diffuse large B-cell and follicular lymphomas (FLs), resembling the pattern seen in reactive tonsils and lymph nodes. We report an index case of FL with CD30 expression, which on initial touch preparations and flow cytometric immunophenotyping revealed a prominent population of CD30(+) cells with marked cellular pleomorphism (anaplasia) in a background of typical FL. Immunohistochemistry of the paraffin section for CD30 in our index case confirmed unequivocal CD30(+) pleomorphic cells in the malignant nodules in occasional clusters. This case prompted a study of additional cases of FL for pattern of immunoreactivity with CD30 on paraffin sections. Twenty-two additional cases of FL (grades 1-3) were retrieved for CD30 immunoperoxidase staining as in the index case. This study demonstrated 32% of the additional cases of FL had definitive CD30(+), large, pleomorphic malignant cells by paraffin immunohistochemistry. In 2 cases (9%), the pattern of immunoreactivity with CD30 showed clustering and variable staining of large cells, as our index case. This study underscores the morphologic and immunophenotypic spectrum of FL that includes CD30 staining and cellular pleomorphism.

Waterfowl populations are resilient to immediate and lagged impacts of wildfires in the boreal forest

USGS Publications Warehouse

Lewis, Tyler; Schmutz, Joel A.; Amundson, Courtney L.; Lindberg, Mark S.

2016-01-01

Summary 1. Wildfires are the principal disturbance in the boreal forest, and their size and frequency are increasing as the climate warms. Impacts of fires on boreal wildlife are largely unknown, especially for the tens of millions of waterfowl that breed in the region. This knowledge gap creates significant barriers to the integrative management of fires and waterfowl, leading to fire policies that largely disregard waterfowl. 2. Waterfowl populations across the western boreal forest of North America have been monitored annually since 1955 by the Waterfowl Breeding Population and Habitat Survey (BPOP), widely considered the most extensive wildlife survey in the world. Using these data, we examined impacts of forest fires on abundance of two waterfowl guilds – dabblers and divers. We modelled waterfowl abundance in relation to fire extent (i.e. amount of survey transect burned) and time since fire, examining both immediate and lagged fire impacts. 3. From 1955 to 2014, >1100 fires in the western boreal forest intersected BPOP survey transects, and many transects burned multiple times. Nonetheless, fires had no detectable impact on waterfowl abundance; annual transect counts of dabbler and diver pairs remained stable from the pre- to post-fire period. 4. The absence of fire impacts on waterfowl abundance extended from the years immediately following the fire to those more than a decade afterwards. Likewise, the amount of transect burned did not influence waterfowl abundance, with similar pair counts from the pre- to post-fire period for small (1–20% burned), medium (21–60%) and large (>60%) burns. 5. Policy implications. Waterfowl populations appear largely resilient to forest fires, providing initial evidence that current policies of limited fire suppression, which predominate throughout much of the boreal forest, have not been detrimental to waterfowl populations. Likewise, fire-related management actions, such as prescribed burning or targeted suppression, seem to have limited impacts on waterfowl abundance and productivity. For waterfowl managers, our results suggest that adaptive models of waterfowl harvest, which annually guide hunting quotas, do not need to emphasize fires when integrating climate change effects.

Experimental demonstration of a two-phase population extinction hazard

PubMed Central

Drake, John M.; Shapiro, Jeff; Griffen, Blaine D.

2011-01-01

Population extinction is a fundamental biological process with applications to ecology, epidemiology, immunology, conservation biology and genetics. Although a monotonic relationship between initial population size and mean extinction time is predicted by virtually all theoretical models, attempts at empirical demonstration have been equivocal. We suggest that this anomaly is best explained with reference to the transient properties of ensembles of populations. Specifically, we submit that under experimental conditions, many populations escape their initially vulnerable state to reach quasi-stationarity, where effects of initial conditions are erased. Thus, extinction of populations initialized far from quasi-stationarity may be exposed to a two-phase extinction hazard. An empirical prediction of this theory is that the fit Cox proportional hazards regression model for the observed survival time distribution of a group of populations will be shown to violate the proportional hazards assumption early in the experiment, but not at later times. We report results of two experiments with the cladoceran zooplankton Daphnia magna designed to exhibit this phenomenon. In one experiment, habitat size was also varied. Statistical analysis showed that in one of these experiments a transformation occurred so that very early in the experiment there existed a transient phase during which the extinction hazard was primarily owing to the initial population size, and that this was gradually replaced by a more stable quasi-stationary phase. In the second experiment, only habitat size unambiguously displayed an effect. Analysis of data pooled from both experiments suggests that the overall extinction time distribution in this system results from the mixture of extinctions during the initial rapid phase, during which the effects of initial population size can be considerable, and a longer quasi-stationary phase, during which only habitat size has an effect. These are the first results, to our knowledge, of a two-phase population extinction process. PMID:21429907

Data Collection and Harmonization in HIV Research: The Seek, Test, Treat, and Retain Initiative at the National Institute on Drug Abuse.

PubMed

Chandler, Redonna K; Kahana, Shoshana Y; Fletcher, Bennett; Jones, Dionne; Finger, Matthew S; Aklin, Will M; Hamill, Kathleen; Webb, Candace

2015-12-01

Large-scale, multisite data sets offer the potential for exploring the public health benefits of biomedical interventions. Data harmonization is an emerging strategy to increase the comparability of research data collected across independent studies, enabling research questions to be addressed beyond the capacity of any individual study. The National Institute on Drug Abuse recently implemented this novel strategy to prospectively collect and harmonize data across 22 independent research studies developing and empirically testing interventions to effectively deliver an HIV continuum of care to diverse drug-abusing populations. We describe this data collection and harmonization effort, collectively known as the Seek, Test, Treat, and Retain Data Collection and Harmonization Initiative, which can serve as a model applicable to other research endeavors.

Clinical outcomes and nadir prostate-specific antigen (PSA) according to initial PSA levels in primary androgen deprivation therapy for metastatic prostate cancer.

PubMed

Kitagawa, Yasuhide; Ueno, Satoru; Izumi, Kouji; Kadono, Yoshifumi; Mizokami, Atsushi; Hinotsu, Shiro; Akaza, Hideyuki; Namiki, Mikio

2016-03-01

To investigate the clinical outcomes of metastatic prostate cancer patients and the relationship between nadir prostate-specific antigen (PSA) levels and different types of primary androgen deprivation therapy (PADT). This study utilized data from the Japan Study Group of Prostate Cancer registry, which is a large, multicenter, population-based database. A total of 2982 patients treated with PADT were enrolled. Kaplan-Meier analysis was used to compare progression-free survival (PFS) and overall survival (OS) in patients treated using combined androgen blockade (CAB) and non-CAB therapies. The relationships between nadir PSA levels and PADT type according to initial serum PSA levels were also investigated. Among the 2982 enrolled patients, 2101 (70.5 %) were treated with CAB. Although CAB-treated patients had worse clinical characteristics, their probability of PFS and OS was higher compared with those treated with a non-CAB therapy. These results were due to a survival benefit with CAB in patients with an initial PSA level of 500-1000 ng/mL. Nadir PSA levels were significantly lower in CAB patients than in non-CAB patients with comparable initial serum PSA levels. A small survival benefit for CAB in metastatic prostate cancer was demonstrated in a Japanese large-scale prospective cohort study. The clinical significance of nadir PSA levels following PADT was evident, but the predictive impact of PSA nadir on OS was different between CAB and non-CAB therapy.

Determinants of geographic inequalities in HPV vaccination in the most populated region of France.

PubMed

Héquet, Delphine; Rouzier, Roman

2017-01-01

In France, there are recommendations and reimbursements for human papillomavirus (HPV) vaccination but no HPV vaccination programs. Therefore, vaccination is largely determined by parents' initiative, which can lead to inequalities. The objective of this study was to determine the factors associated with poorer vaccination coverage rates in the most populated region of France. The data of this study were obtained from the National Health Insurance between 2011 and 2013. Correlations between vaccination initiation rate (at least 1 dose reimbursed) and socio-demographic/cultural factors were assessed using Pearson's product-moment correlation coefficient. Multivariate analyses were performed using logistic regression. In total, 121,636 girls received at least one HPV vaccine dose. The vaccination rate for girls born from 1996 to 1999 was 18.7%. Disparities in vaccination coverage rates were observed between the 8 departments of the region, ranging from 12.9% to 22.6%. At the department level, unemployment, proportion of immigrants and foreigners, and coverage by CMU health insurance ("Couverture Maladie Universelle", a health insurance plan for those who are not otherwise covered through business or employment and who have a low income) were significantly inversely correlated with vaccination rates, whereas urban residence, medical density, income and use of medical services were not related to coverage. In the multivariate model, only the percentage of foreigners remained independently associated with lower vaccination coverage. At the individual level, the use of medical services was a strong driver of HPV vaccination initiation. We observed geographic disparities in HPV vaccination initiation coverage. Even if no clear factor was identified as a vaccination determinant, we observed a failure of vaccination only based on parents' initiative. Therefore, an organized policy on HPV vaccination, such as school-based programs, can help improve coverage rates.

Preparing for the 21st century: introducing a service approach.

PubMed

He, S

1995-08-01

While China's strong population policy remains unchanged, the State Family Planning (FP) Commission is experimenting with innovations designed to improve service delivery and promote gender equity. China entered demographic transition with a large population base which obviated the luxury of achieving the transition gradually over time. Because mortality rates have dropped dramatically and there is a large cohort of people of reproductive age, China adds 14-15 million people to its population each year. Were it not for the FP program, China's current population of 1.2 billion would be about 300 million higher. Economic reform has meant that most Chinese people have their basic needs met and can strive to improve the quality of their lives. These same reforms have weakened the collective systems of financing reproductive health systems, however, and new systems of local support must be found. China's Agenda 21, which sets goals for the 21st century, cites the education of girls and women as a key step to achieving a sustainable population size. In addition to an emphasis on reproductive health, China is initiating programs in adolescent health, sex education, and AIDS prevention. China's National FP Program for 1995-2000 emphasizes these changes and identifies a strong information, education, and communication component as a priority. Innovations, such as a participatory approach to training grassroots workers in interpersonal skills and counseling, are being field tested as a preliminary step toward full implementation. Training workshops are also being held to prepare FP leaders to uphold FP laws and protest the rights of the public.

Genomic signatures of geographic isolation and natural selection in coral reef fishes.

PubMed

Gaither, Michelle R; Bernal, Moisés A; Coleman, Richard R; Bowen, Brian W; Jones, Shelley A; Simison, W Brian; Rocha, Luiz A

2015-04-01

The drivers of speciation remain among the most controversial topics in evolutionary biology. Initially, Darwin emphasized natural selection as a primary mechanism of speciation, but the architects of the modern synthesis largely abandoned that view in favour of divergence by geographic isolation. The balance between selection and isolation is still at the forefront of the evolutionary debate, especially for the world's tropical oceans where biodiversity is high, but isolating barriers are few. Here, we identify the drivers of speciation in Pacific reef fishes of the genus Acanthurus by comparative genome scans of two peripheral populations that split from a large Central-West Pacific lineage at roughly the same time. Mitochondrial sequences indicate that populations in the Hawaiian Archipelago and the Marquesas Islands became isolated approximately 0.5 Ma. The Hawaiian lineage is morphologically indistinguishable from the widespread Pacific form, but the Marquesan form is recognized as a distinct species that occupies an unusual tropical ecosystem characterized by upwelling, turbidity, temperature fluctuations, algal blooms and little coral cover. An analysis of 3737 SNPs reveals a strong signal of selection at the Marquesas, with 59 loci under disruptive selection including an opsin Rh2 locus. While both the Hawaiian and Marquesan populations indicate signals of drift, the former shows a weak signal of selection that is comparable with populations in the Central-West Pacific. This contrast between closely related lineages reveals one population diverging due primarily to geographic isolation and genetic drift, and the other achieving taxonomic species status under the influence of selection. © 2015 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Predicting population dynamics from the properties of individuals: a cross-level test of dynamic energy budget theory.

PubMed

Martin, Benjamin T; Jager, Tjalling; Nisbet, Roger M; Preuss, Thomas G; Grimm, Volker

2013-04-01

Individual-based models (IBMs) are increasingly used to link the dynamics of individuals to higher levels of biological organization. Still, many IBMs are data hungry, species specific, and time-consuming to develop and analyze. Many of these issues would be resolved by using general theories of individual dynamics as the basis for IBMs. While such theories have frequently been examined at the individual level, few cross-level tests exist that also try to predict population dynamics. Here we performed a cross-level test of dynamic energy budget (DEB) theory by parameterizing an individual-based model using individual-level data of the water flea, Daphnia magna, and comparing the emerging population dynamics to independent data from population experiments. We found that DEB theory successfully predicted population growth rates and peak densities but failed to capture the decline phase. Further assumptions on food-dependent mortality of juveniles were needed to capture the population dynamics after the initial population peak. The resulting model then predicted, without further calibration, characteristic switches between small- and large-amplitude cycles, which have been observed for Daphnia. We conclude that cross-level tests help detect gaps in current individual-level theories and ultimately will lead to theory development and the establishment of a generic basis for individual-based models and ecology.

Towards low back support with a passive biomimetic exo-spine.

PubMed

Naf, Matthias B; De Rijcke, Laura; Guerrero, Carlos Rodriguez; Millard, Matthew; Vanderborght, Bram; Lefeber, Dirk

2017-07-01

Low-Back Pain (LBP) affects a large portion of the working population. Preventive exoskeletons have been proposed to reduce the moments on the lower back, specifically around the lumbosacral (L5/S1) joint. High correlation has been shown, between reducing the moments around the L5/S1 joint and intervertebral compression forces, which in turn have been identified as a risk factor for developing LBP. However, most passive back support exoskeletons use rigid plates or stiff beams to support the spine that limit the range of motion of the wearer. A large range of motion and versatility are especially desirable for industrial applications. To overcome these limitations, a passive biomimetic exo-spine has been designed, modelled and an initial prototype tested. Its potential to allow for a large range of motion, whilst at the same time limiting the most extreme and potentially harmful postures has been shown.

Precursory seismicity associated with frequent, large ice avalanches on Iliamna Volcano, Alaska, USA

USGS Publications Warehouse

Caplan-Auerbach, Jacqueline; Huggel, C.

2007-01-01

Since 1994, at least six major (volume>106 m3) ice and rock avalanches have occurred on Iliamna volcano, Alaska, USA. Each of the avalanches was preceded by up to 2 hours of seismicity believed to represent the initial stages of failure. Each seismic sequence begins with a series of repeating earthquakes thought to represent slip on an ice-rock interface, or between layers of ice. This stage is followed by a prolonged period of continuous ground-shaking that reflects constant slip accommodated by deformation at the glacier base. Finally the glacier fails in a large avalanche. Some of the events appear to have entrained large amounts of rock, while others comprise mostly snow and ice. Several avalanches initiated from the same source region, suggesting that this part of the volcano is particularly susceptible to failure, possibly due to the presence of nearby fumaroles. Although thermal conditions at the time of failure are not well constrained, it is likely that geothermal energy causes melting at the glacier base, promoting slip and culminating in failure. The frequent nature and predictable failure sequence of Iliamna avalanches makes the volcano an excellent laboratory for the study of ice avalanches. The prolonged nature of the seismic signal suggests that warning may one day be given for similar events occurring in populated regions.

Plasmacytoid pre-dendritic cells (pDC): from molecular pathways to function and disease association.

PubMed

Alculumbre, Solana; Raieli, Salvatore; Hoffmann, Caroline; Chelbi, Rabie; Danlos, François-Xavier; Soumelis, Vassili

2018-02-19

Plasmacytoid pre-dendritic cells (pDC) are a specialized DC population with a great potential to produce large amounts of type I interferon (IFN). pDC are involved in the initiation of antiviral immune responses through their interaction with innate and adaptive immune cell populations. In a context-dependent manner, pDC activation can induce their differentiation into mature DC able to induce both T cell activation or tolerance. In this review, we described pDC functions during immune responses and their implication in the clearance or pathogenicity of human diseases during infection, autoimmunity, allergy and cancer. We discuss recent advances in the field of pDC biology and their implication for future studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Toward a theory of topopatric speciation: The role of genetic assortative mating

NASA Astrophysics Data System (ADS)

Schneider, David M.; do Carmo, Eduardo; Martins, Ayana B.; de Aguiar, Marcus A. M.

2014-09-01

We discuss a minimalist model of assortative mating for sexually reproducing haploid individuals with two biallelic loci. Assortativeness is introduced in the model by preventing mating between individuals whose alleles differ at both loci. Using methods of dynamical systems and population genetics we provide a full description of the evolution of the system for the case of very large populations. We derive the equations governing the evolution of haplotype frequencies and study the equilibrium solutions, stability, and speed of convergence to equilibrium. We find a constant of motion which allows us to introduce a geometrical construction that makes it straightforward to predict the fate of initial conditions. Finally, we discuss the consequences of this class of assortative mating models, including their possible extensions and implications for sympatric and topopatric speciation.

Please don't misuse the museum: 'declines' may be statistical.

PubMed

Campbell Grant, Evan H

2015-03-01

Detecting declines in populations at broad spatial scales takes enormous effort, and long-term data are often more sparse than is desired for estimating trends, identifying drivers for population changes, framing conservation decisions, or taking management actions. Museum records and historic data can be available at large scales across multiple decades, and are therefore an attractive source of information on the comparative status of populations. However, changes in populations may be real (e.g. in response to environmental covariates) or resulting from variation in our ability to observe the true population response (also possibly related to environmental covariates). This is a (statistical) nuisance in understanding the true status of a population. Evaluating statistical hypotheses alongside more interesting ecological ones is important in the appropriate use of museum data. Two statistical considerations are generally applicable to use of museum records: first without initial random sampling, comparison with contemporary results cannot provide inference to the entire range of a species, and second the availability of only some individuals in a population may respond to environmental changes. Changes in the availability of individuals may reduce the proportion of the population that is present and able to be counted on a given survey event, resulting in an apparent decline even when population size is stable. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Size-assortative mating and effect of maternal body size on the reproductive output of the nassariid Buccinanops globulosus

NASA Astrophysics Data System (ADS)

Avaca, María Soledad; Narvarte, Maite; Martín, Pablo

2012-04-01

Size- assortative mating is usually present in populations where there is a positive relationship between female size and reproductive output. In this study, we tested for the presence of sexual size dimorphism, size-assortative mating and the effects of female size on reproductive output in a wild population of Buccinanops globulosus, an endemic nassariid of the Southwestern Atlantic Ocean with direct development. The results showed that: 1) females were larger than males, indicating sexual size dimorphism; 2) mate sizes were significantly correlated, indicating a component of size-assortative mating; 3) males of medium and large size classes were paired with larger females than small-sized males; 4) larger females were paired with large males; 5) maternal body size was positively related to some proxies of reproductive success (number of nurse eggs per egg capsule, egg capsular area and total length at hatching). Our results suggest that larger females may be favored as mates over smaller ones owing to their higher investment per offspring and consequently a larger initial juvenile size as juvenile.

Constraining the Statistics of Population III Binaries

NASA Technical Reports Server (NTRS)

Stacy, Athena; Bromm, Volker

2012-01-01

We perform a cosmological simulation in order to model the growth and evolution of Population III (Pop III) stellar systems in a range of host minihalo environments. A Pop III multiple system forms in each of the ten minihaloes, and the overall mass function is top-heavy compared to the currently observed initial mass function in the Milky Way. Using a sink particle to represent each growing protostar, we examine the binary characteristics of the multiple systems, resolving orbits on scales as small as 20 AU. We find a binary fraction of approx. 36, with semi-major axes as large as 3000 AU. The distribution of orbital periods is slightly peaked at approx. < 900 yr, while the distribution of mass ratios is relatively flat. Of all sink particles formed within the ten minihaloes, approx. 50 are lost to mergers with larger sinks, and 50 of the remaining sinks are ejected from their star-forming disks. The large binary fraction may have important implications for Pop III evolution and nucleosynthesis, as well as the final fate of the first stars.

Trends in adolescent smoking initiation in the United States: is tobacco marketing an influence?

PubMed

Gilpin, E A; Pierce, J P

1997-01-01

To compare recent trends in smoking initiation by adolescents with trends in inflation-adjusted cigarette pricing and tobacco marketing expenditures. We examined smoking initiation trends in demographic subgroups of adolescents aged 14-17 years during the decade 1979-1989. Data on cigarette pricing and tobacco marketing expenditures were adjusted for inflation and plotted over this same period. Large population surveys, United States. 140,975 ever-smokers aged 17-38 when surveyed in 1992 or 1993, who reported on age of smoking initiation during the decade 1979-1989. Initiation rate was calculated as the number in an age group who reported starting to smoke regularly in a year, divided by the number of never-smokers at the start of the year. Trends were evaluated by linear and quadratic models. From 1979 to 1984, adolescent initiation rates decreased, but increased thereafter, particularly among males, whites, and those who, as adults, reported never having graduated from high school. Cigarette price increased throughout the decade as did tobacco marketing expenditures, especially for coupons, value-added items, and promotional allowances. Availability of cheaper cigarettes is not likely to be a cause of increased smoking initiation by adolescents. Although other influences cannot be ruled out, we suspect that the expanded tobacco marketing budget, with its increased emphasis on tactics that may be particularly pertinent to young people, affected adolescent initiation rates.

Development of genetic diversity, differentiation and structure over 500 years in four ponderosa pine populations.

PubMed

Lesser, M R; Parchman, T L; Jackson, S T

2013-05-01

Population history plays an important role in shaping contemporary levels of genetic variation and geographic structure. This is especially true in small, isolated range-margin populations, where effects of inbreeding, genetic drift and gene flow may be more pronounced than in large continuous populations. Effects of landscape fragmentation and isolation distance may have implications for persistence of range-margin populations if they are demographic sinks. We studied four small, disjunct populations of ponderosa pine over a 500-year period. We coupled demographic data obtained through dendroecological methods with microsatellite data to discern how and when contemporary levels of allelic diversity, among and within-population levels of differentiation, and geographic structure, arose. Alleles accumulated rapidly following initial colonization, demonstrating proportionally high levels of gene flow into the populations. At population sizes of approximately 100 individuals, allele accumulation saturated. Levels of genetic differentiation among populations (F(ST) and Jost's D(est)) and diversity within populations (F(IS)) remained stable through time. There was no evidence of geographic genetic structure at any time in the populations' history. Proportionally, high gene flow in the early stages of population growth resulted in rapid accumulation of alleles and quickly created relatively homogenous genetic patterns among populations. Our study demonstrates that contemporary levels of genetic diversity were formed quickly and early in population development. How contemporary genetic diversity accumulates over time is a key facet of understanding population growth and development. This is especially relevant given the extent and speed at which species ranges are predicted to shift in the coming century. © 2013 Blackwell Publishing Ltd.

The impact of land reform on the status of large carnivores in Zimbabwe

PubMed Central

Williams, Kathryn S.; Joubert, Christoffel J.

2016-01-01

Large carnivores are decreasing in number due to growing pressure from an expanding human population. It is increasingly recognised that state-protected conservation areas are unlikely to be sufficient to protect viable populations of large carnivores, and that private land will be central to conservation efforts. In 2000, a fast-track land reform programme (FTLRP) was initiated in Zimbabwe, ostensibly to redress the racial imbalance in land ownership, but which also had the potential to break up large areas of carnivore habitat on private land. To date, research has focused on the impact of the FTLRP process on the different human communities, while impacts on wildlife have been overlooked. Here we provide the first systematic assessment of the impact of the FTLRP on the status of large carnivores. Spoor counts were conducted across private, resettled and communal land use types in order to estimate the abundance of large carnivores, and to determine how this had been affected by land reform. The density of carnivore spoor differed significantly between land use types, and was lower on resettlement land than on private land, suggesting that the resettlement process has resulted in a substantial decline in carnivore abundance. Habitat loss and high levels of poaching in and around resettlement areas are the most likely causes. The FTLRP resulted in the large-scale conversion of land that was used sustainably and productively for wildlife into unsustainable, unproductive agricultural land uses. We recommended that models of land reform should consider the type of land available, that existing expertise in land management should be retained where possible, and that resettlement programmes should be carefully planned in order to minimise the impacts on wildlife and on people. PMID:26819838

Large-scale galaxy flow from a non-gravitational impulse

NASA Technical Reports Server (NTRS)

Hogan, Craig J.; Kaiser, Nick

1989-01-01

A theory is presented describing linear perturbations of an expanding universe containing multiple, independently perturbed, collisionless, gravitationally coupled constituents. Solutions are found in the limit where one initially unperturbed component dominates the total density. The theory is applied to perturbations generated by a nongravitational process in one or more of the light components, as would occur in explosive or radiation-pressure-instability theories of galaxy formation. The apparent dynamical density parameter and correlations between density and velocity amplitude for various populations, are evaluated as a function of cosmic scale factor.

Full-spectrum disease response : beyond just the flu.

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

Knazovich, Michael Ward; Cox, Warren B.; Henderson, Samuel Arthur

Why plan beyond the flu: (1) the installation may be the target of bioterrorism - National Laboratory, military base collocated in large population center; and (2) International Airport - transport of infectious agents to the area - Sandia is a global enterprise and staff visit many foreign countries. In addition to the Pandemic Plan, Sandia has developed a separate Disease Response Plan (DRP). The DRP addresses Category A, B pathogens and Severe Acute Respiratory Syndrome (SARS). The DRP contains the Cities Readiness Initiative sub-plan for disbursement of Strategic National Stockpile assets.

The founder-cell transcriptome in the Arabidopsis apetala1 cauliflower inflorescence meristem.

PubMed

Frerichs, Anneke; Thoma, Rahere; Abdallah, Ali Taleb; Frommolt, Peter; Werr, Wolfgang; Chandler, John William

2016-11-03

Although the pattern of lateral organ formation from apical meristems establishes species-specific plant architecture, the positional information that confers cell fate to cells as they transit to the meristem flanks where they differentiate, remains largely unknown. We have combined fluorescence-activated cell sorting and RNA-seq to characterise the cell-type-specific transcriptome at the earliest developmental time-point of lateral organ formation using DORNRÖSCHEN-LIKE::GFP to mark founder-cell populations at the periphery of the inflorescence meristem (IM) in apetala1 cauliflower double mutants, which overproliferate IMs. Within the lateral organ founder-cell population at the inflorescence meristem, floral primordium identity genes are upregulated and stem-cell identity markers are downregulated. Additional differentially expressed transcripts are involved in polarity generation and boundary formation, and in epigenetic and post-translational changes. However, only subtle transcriptional reprogramming within the global auxin network was observed. The transcriptional network of differentially expressed genes supports the hypothesis that lateral organ founder-cell specification involves the creation of polarity from the centre to the periphery of the IM and the establishment of a boundary from surrounding cells, consistent with bract initiation. However, contrary to the established paradigm that sites of auxin response maxima pre-pattern lateral organ initiation in the IM, auxin response might play a minor role in the earliest stages of lateral floral initiation.

Practical approaches to adverse outcome pathway (AOP) ...

EPA Pesticide Factsheets

Adverse Outcome Pathways (AOPs) describe toxicant effects as a sequential chain of causally linked events beginning with a molecular perturbation and culminating in an adverse outcome at an individual or population level. Strategies for developing AOPs are still evolving and depend largely on the intended use or motivation for development. Four ecological AOP case studies, which were developed for different purposes, are described herein. In each situation, creation of the AOP began in a manner determined by the initial motivation for its creation, and expanded either to include additional components of the pathway, or to address the domains of applicability in terms of chemical initiators, susceptible species, life stages, etc. From these case studies, some general strategies can be gleaned which a developer may find useful for supporting an existing AOP or creating a new one. Several web-based tools which can aid in AOP assembly, as well as evaluation of weight of evidence for scientific robustness of AOP components are highlighted. The need for AOP development and greater population of AOPs in the online knowledgebase has been widely recognized (e.g., OECD Project 1.29, Knapen et al 2015, Escher et al 2016; Groh et al 2015), but currently there are few AOP developers. To promote broader development of AOPs, and the inclusion of potential developers across various types of institutes and fields of study, this manuscript outlines strategies for initiating

Embargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation?

PubMed Central

Bouché, Philippe; Crosmary, William; Kafando, Pierre; Doamba, Benoit; Kidjo, Ferdinand Claude; Vermeulen, Cédric; Chardonnet, Philippe

2016-01-01

The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230–648) adults and sub-adult individuals, comparable to the 311 (123–498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa. PMID:27182985

Embargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation?

PubMed

Bouché, Philippe; Crosmary, William; Kafando, Pierre; Doamba, Benoit; Kidjo, Ferdinand Claude; Vermeulen, Cédric; Chardonnet, Philippe

2016-01-01

The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230-648) adults and sub-adult individuals, comparable to the 311 (123-498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa.

Circumbinary planet formation in the Kepler-16 system. II. A toy model for in situ planet formation within a debris belt

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

Meschiari, Stefano, E-mail: stefano@astro.as.utexas.edu

2014-07-20

Recent simulations have shown that the formation of planets in circumbinary configurations (such as those recently discovered by Kepler) is dramatically hindered at the planetesimal accretion stage. The combined action of the binary and the protoplanetary disk acts to raise impact velocities between kilometer-sized planetesimals beyond their destruction threshold, halting planet formation within at least 10 AU from the binary. It has been proposed that a primordial population of 'large' planetesimals (100 km or more in size), as produced by turbulent concentration mechanisms, would be able to bypass this bottleneck; however, it is not clear whether these processes are viablemore » in the highly perturbed circumbinary environments. We perform two-dimensional hydrodynamical and N-body simulations to show that kilometer-sized planetesimals and collisional debris can drift and be trapped in a belt close to the central binary. Within this belt, planetesimals could initially grow by accreting debris, ultimately becoming 'indestructible' seeds that can accrete other planetesimals in situ despite the large impact speeds. We find that large, indestructible planetesimals can be formed close to the central binary within 10{sup 5} yr, therefore showing that even a primordial population of 'small' planetesimals can feasibly form a planet.« less

Using binary statistics in Taurus-Auriga to distinguish between brown dwarf formation processes

NASA Astrophysics Data System (ADS)

Marks, M.; Martín, E. L.; Béjar, V. J. S.; Lodieu, N.; Kroupa, P.; Manjavacas, E.; Thies, I.; Rebolo López, R.; Velasco, S.

2017-08-01

Context. One of the key questions of the star formation problem is whether brown dwarfs (BDs) form in the manner of stars directly from the gravitational collapse of a molecular cloud core (star-like) or whether BDs and some very low-mass stars (VLMSs) constitute a separate population that forms alongside stars comparable to the population of planets, for example through circumstellar disk (peripheral) fragmentation. Aims: For young stars in Taurus-Auriga the binary fraction has been shown to be large with little dependence on primary mass above ≈ 0.2 M⊙, while for BDs the binary fraction is < 10%. Here we investigate a case in which BDs in Taurus formed dominantly, but not exclusively, through peripheral fragmentation, which naturally results in small binary fractions. The decline of the binary frequency in the transition region between star-like formation and peripheral formation is modelled. Methods: We employed a dynamical population synthesis model in which stellar binary formation is universal with a large binary fraction close to unity. Peripheral objects form separately in circumstellar disks with a distinctive initial mass function (IMF), their own orbital parameter distributions for binaries, and small binary fractions, according to observations and expectations from smoothed particle hydrodynamics (SPH) and grid-based computations. A small amount of dynamical processing of the stellar component was accounted for as appropriate for the low-density Taurus-Auriga embedded clusters. Results: The binary fraction declines strongly in the transition region between star-like and peripheral formation, exhibiting characteristic features. The location of these features and the steepness of this trend depend on the mass limits for star-like and peripheral formation. Such a trend might be unique to low density regions, such as Taurus, which host binary populations that are largely unprocessed dynamically in which the binary fraction is large for stars down to M-dwarfs and small for BDs. Conclusions: The existence of a strong decline in the binary fraction - primary mass diagram will become verifiable in future surveys on BD and VLMS binarity in the Taurus-Auriga star-forming region. The binary fraction - primary mass diagram is a diagnostic of the (non-)continuity of star formation along the mass scale, the separateness of the stellar and BD populations, and the dominant formation channel for BDs and BD binaries in regions of low stellar density hosting dynamically unprocessed populations.

Nonlinear saturation of the Weibel instability

DOE PAGES

Cagas, P.; Hakim, A.; Scales, W.; ...

2017-11-21

The growth and saturation of magnetic fields due to the Weibel instability (WI) have important implications for laboratory and astrophysical plasmas, and this has drawn significant interest recently. Since the WI can generate a large magnetic field from no initial field, the maximum magnitudes achieved can have significant consequences for a number of applications. Hence, an understanding of the detailed dynamics driving the nonlinear saturation of the WI is important. This work considers the nonlinear saturation of the WI when counter-streaming populations of initially unmagnetized electrons are perturbed by a magnetic field oriented perpendicular to the direction of streaming. Previousmore » works have found magnetic trapping to be important and connected electron skin depth spatial scales to the nonlinear saturation of the WI. The results presented in this work are consistent with these findings for a high-temperature case. However, using a high-order continuum kinetic simulation tool, this work demonstrates that when the electron populations are colder, a significant electrostatic potential develops that works with the magnetic field to create potential wells. The electrostatic field develops due to transverse flows induced by the WI and in some cases is strengthened by a secondary instability. This field plays a key role in saturation of the WI for colder populations. In conclusion, the role of the electrostatic potential in Weibel instability saturation has not been studied in detail previously.« less

Recruitment and Participation of Recreational Runners in a Large Epidemiological and Genetic Research Study: Retrospective Data Analysis.

PubMed

Manzanero, Silvia; Kozlovskaia, Maria; Vlahovich, Nicole; Hughes, David C

2018-05-23

With the increasing capacity for remote collection of both data and samples for medical research, a thorough assessment is needed to determine the association of population characteristics and recruitment methodologies with response rates. The aim of this research was to assess population representativeness in a two-stage study of health and injury in recreational runners, which consisted of an epidemiological arm and genetic analysis. The cost and success of various classical and internet-based methods were analyzed, and demographic representativeness was assessed for recruitment to the epidemiological survey, reported willingness to participate in the genetic arm of the study, actual participation, sample return, and approval for biobank storage. A total of 4965 valid responses were received, of which 1664 were deemed eligible for genetic analysis. Younger age showed a negative association with initial recruitment rate, expressed willingness to participate in genetic analysis, and actual participation. Additionally, female sex was associated with higher initial recruitment rates, and ethnic origin impacted willingness to participate in the genetic analysis (all P<.001). The sharp decline in retention through the different stages of the study in young respondents suggests the necessity to develop specific recruitment and retention strategies when investigating a young, physically active population. ©Silvia Manzanero, Maria Kozlovskaia, Nicole Vlahovich, David C Hughes. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 23.05.2018.

Nonlinear saturation of the Weibel instability

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

Cagas, P.; Hakim, A.; Scales, W.

The growth and saturation of magnetic fields due to the Weibel instability (WI) have important implications for laboratory and astrophysical plasmas, and this has drawn significant interest recently. Since the WI can generate a large magnetic field from no initial field, the maximum magnitudes achieved can have significant consequences for a number of applications. Hence, an understanding of the detailed dynamics driving the nonlinear saturation of the WI is important. This work considers the nonlinear saturation of the WI when counter-streaming populations of initially unmagnetized electrons are perturbed by a magnetic field oriented perpendicular to the direction of streaming. Previousmore » works have found magnetic trapping to be important and connected electron skin depth spatial scales to the nonlinear saturation of the WI. The results presented in this work are consistent with these findings for a high-temperature case. However, using a high-order continuum kinetic simulation tool, this work demonstrates that when the electron populations are colder, a significant electrostatic potential develops that works with the magnetic field to create potential wells. The electrostatic field develops due to transverse flows induced by the WI and in some cases is strengthened by a secondary instability. This field plays a key role in saturation of the WI for colder populations. In conclusion, the role of the electrostatic potential in Weibel instability saturation has not been studied in detail previously.« less

Population age and initial density in a patchy environment affect the occurrence of abrupt transitions in a birth-and-death model of Taylor's law

USGS Publications Warehouse

Jiang, Jiang; DeAngelis, Donald L.; Zhang, B.; Cohen, J.E.

2014-01-01

Taylor's power law describes an empirical relationship between the mean and variance of population densities in field data, in which the variance varies as a power, b, of the mean. Most studies report values of b varying between 1 and 2. However, Cohen (2014a) showed recently that smooth changes in environmental conditions in a model can lead to an abrupt, infinite change in b. To understand what factors can influence the occurrence of an abrupt change in b, we used both mathematical analysis and Monte Carlo samples from a model in which populations of the same species settled on patches, and each population followed independently a stochastic linear birth-and-death process. We investigated how the power relationship responds to a smooth change of population growth rate, under different sampling strategies, initial population density, and population age. We showed analytically that, if the initial populations differ only in density, and samples are taken from all patches after the same time period following a major invasion event, Taylor's law holds with exponent b=1, regardless of the population growth rate. If samples are taken at different times from patches that have the same initial population densities, we calculate an abrupt shift of b, as predicted by Cohen (2014a). The loss of linearity between log variance and log mean is a leading indicator of the abrupt shift. If both initial population densities and population ages vary among patches, estimates of b lie between 1 and 2, as in most empirical studies. But the value of b declines to ~1 as the system approaches a critical point. Our results can inform empirical studies that might be designed to demonstrate an abrupt shift in Taylor's law.

Articulated dental cast analysis of asymptomatic and symptomatic populations

PubMed Central

Cordray, Frank E

2016-01-01

Dental instrumentation has long provided insight into the mechanism of musculo-skeletal function of the gnathic system. While large population studies associate dental arch displacement (DAD), especially laterally, with symptoms, mandibular condyle displacement (CD) resulting from DAD has not been targeted as possibly etiologic in the production of common muscle contraction headache (CMCH) and temporo-mandibular dysfunction (TMD). The objective was to evaluate the three-dimensional nature of DAD and CD between the seated condylar position (SCP) and the intercuspal position (ICP) and to compare results derived from large deprogrammed asymptomatic and symptomatic populations. A total of 1 192 sets of dental casts collected from asymptomatic and symptomatic populations were articulated in the SCP. The initial occlusal contact, DAD, and condylar displacement were evaluated for frequency, direction, and magnitude of displacement between the SCP and ICP. The data revealed significant displacement between the SCP and ICP of the condyles (displaced most frequently inferior (down) and posterior (distal)) and substantially increased frequency and magnitude of displacement of the dental arches (with posterior premature occlusal contacts, increased overjet, decreased overbite, midline differences, and occlusal classification changes) in symptomatic subjects. These discrepancies were statistically significant and clinically significant. The data support the concept of increased DAD and CD with dysfunction. Transverse condylar displacement, commonly presenting with dental cross bite, may be associated with CMCH and TMD. Displacement of the mandibular condyle may be an etiologic factor in CMCH and dysfunction of the temporo-mandibular joint. PMID:27357324

Quality Improvement Initiatives: The Missed Opportunity for Health Plans

PubMed Central

Fernandez-Lopez, Sara; Lennert, Barbara

2009-01-01

Background The increase in healthcare cost without direct improvements in health outcomes, coupled with a desire to expand access to the large uninsured population, has underscored the importance of quality initiatives and organizations that provide more affordable healthcare by maximizing value. Objectives To determine the knowledge of managed care organizations about quality organizations and initiatives and to identify potential opportunities in which pharmaceutical companies could collaborate with health plans in the development and implementation of quality initiatives. Methods We conducted a survey of 36 pharmacy directors and 15 medical directors of different plans during a Managed Care Network meeting in 2008. The represented plans cover almost 74 million lives in commercial, Medicare, and Medicaid programs, or a combination of them. Results The responses show limited knowledge among pharmacy and medical directors about current quality organizations and initiatives, except for quality organizations that provide health plan quality accreditation. The results also reveal an opportunity for pharmaceutical companies to collaborate with private health plans in the development of quality initiatives, especially those related to drug utilization, such as patient adherence and education and correct drug utilization. Conclusion Our survey shows clearly that today's focus for managed care organizations is mostly limited to the organizations that provide health plan quality accreditation, with less focus on other organizations. PMID:25126303

Quality improvement initiatives: the missed opportunity for health plans.

PubMed

Fernandez-Lopez, Sara; Lennert, Barbara

2009-11-01

The increase in healthcare cost without direct improvements in health outcomes, coupled with a desire to expand access to the large uninsured population, has underscored the importance of quality initiatives and organizations that provide more affordable healthcare by maximizing value. To determine the knowledge of managed care organizations about quality organizations and initiatives and to identify potential opportunities in which pharmaceutical companies could collaborate with health plans in the development and implementation of quality initiatives. We conducted a survey of 36 pharmacy directors and 15 medical directors of different plans during a Managed Care Network meeting in 2008. The represented plans cover almost 74 million lives in commercial, Medicare, and Medicaid programs, or a combination of them. The responses show limited knowledge among pharmacy and medical directors about current quality organizations and initiatives, except for quality organizations that provide health plan quality accreditation. The results also reveal an opportunity for pharmaceutical companies to collaborate with private health plans in the development of quality initiatives, especially those related to drug utilization, such as patient adherence and education and correct drug utilization. Our survey shows clearly that today's focus for managed care organizations is mostly limited to the organizations that provide health plan quality accreditation, with less focus on other organizations.

Spectral Study of Measles Epidemics: The Dependence of Spectral Gradient on the Population Size of the Community

NASA Astrophysics Data System (ADS)

Sumi, Ayako; Olsen, Lars Folke; Ohtomo, Norio; Tanaka, Yukio; Sawamura, Sadashi

2003-02-01

We have carried out spectral analysis of measles notifications in several communities in Denmark, UK and USA. The results confirm that each power spectral density (PSD) shows exponential characteristics, which are universally observed in the PSD for time series generated from nonlinear dynamical system. The exponential gradient increases with the population size. For almost all communities, many spectral lines observed in each PSD can be fully assigned to linear combinations of several fundamental periods, suggesting that the measles data are substantially noise-free. The optimum least squares fitting curve calculated using these fundamental periods essentially reproduces an underlying variation of the measles data, and an extension of the curve can be used to predict measles epidemics. For the communities with large population sizes, some PSD patterns obtained from segment time series analysis show a close resemblance to the PSD patterns at the initial stages of a period-doubling bifurcation process for the so-called susceptible/exposed/infectious/recovered (SEIR) model with seasonal forcing. The meaning of the relationship between the exponential gradient and the population size is discussed.

Genetic structure of faucet snail, Bithynia tentaculata populations in North Americal based on microsattelite markers

USGS Publications Warehouse

Perez, Kathryn E.; Werren, Rebecca L.; Lynum, Christopher A.; Hartman, Levi A.; Majoros, Gabor; Cole, Rebecca A.

2016-01-01

Bithynia tentaculata is believed to have been extirpated from North America during the last glacial maximum. It was reintroduced into North America via the Great Lakes basin in the 1800’s and has recently been expanding its geographic range. This snail serves as intermediate host for three trematodes that cause extensive recurring morbidity and mortality events in migratory water birds along the Mississippi River. Using twelve microsatellite loci for ~200 individual snails from 11 populations in North America and Europe, we examined one of the three major geographic regions from which founding populations into the Great Lakes typically originate. Our data supports a single recolonization of North America into the Great Lakes Basin followed by subsequent introduction events from the Great Lakes to other large watersheds in North America. However, additional watersheds in Europe require sampling to confirm this result. No populations with genetic signatures indicative of North American glacial relics were found. The initial invasion of North America was likely not from the Ponto-Caspian basin, the usual source of freshwater invasive species to the Laurentian Great Lakes.

US cardiologist workforce from 1995 to 2007: modest growth, lasting geographic maldistribution, especially in rural areas

PubMed Central

Aneja, Sanjay; Ross, Joseph S.; Wang, Yongfei; Matsumoto, Masatoshi; Rodgers, George P.; Bernheim, Susannah M.; Rathore, Saif S.; Krumholz, Harlan M.

2012-01-01

A sufficient cardiology workforce is necessary to ensure access to cardiovascular care. Specifically, access to cardiologists is important in the management and treatment of chronic cardiovascular disease. Previous workforce analyses focused narrowly on the total numbers necessary to care for the entire population and not the geographic distribution of the workforce. To examine the supply and distribution of the cardiologist workforce, we mapped the ratios of cardiologists, primary care physicians, and total physicians to the population aged 65 years or older within different Hospital Referral Regions from the years 1995 and 2007. We found within the 12-year span of our study growth in the cardiology workforce was modest compared to the primary care physician and total physician workforces. Also we found a persistent geographic misdistribution of cardiologists associated with socioeconomic population characteristics. Our results suggest that large segments of our population, specifically in rural areas, continue to have decreased access to cardiologists despite a modest growth in the overall workforce. Policy initiatives focused upon increasing the cardiologist workforces in these areas in necessary to provide adequate cardiovascular care. PMID:22147857

How will the 'cancer moonshot' impact health disparities?

PubMed

Ramirez, Amelie G; Thompson, Ian M

2017-09-01

In 1971, President Nixon signed into law the National Cancer Act (NCA), colloquially known as the "War on Cancer", which pushed cancer onto the national agenda and is credited for many subsequent increases in the knowledge of the molecular, cellular, and genetic causes and effects of cancer. But even though cancer mortality has declined overall in intervening years after the NCA, cancer health disparities persist in the form of higher cancer incidence and mortality rates among certain cancer types and certain populations. Breast and cervical cancers disproportionately affect African American, Hispanic, and American Indian Women. Colorectal cancer is the second leading cause of death for Latinos (with men and women combined). Forty-five years after the NCA, how will the next enormous cancer initiatives-President Barack Obama's Cancer Moonshot and the All of Us Research Program (formerly the Precision Medicine Initiative Cohort Program)-impact cancer health disparities? The emergence of precision medicine and the sharing of information across sectors are at the heart of these large national initiatives and hold vast potential to address complex health disparities that remain in incidence reporting, incidence, treatment, prognoses, and mortality among certain cancer types and racial/ethnic minorities, including African Americans and Hispanics/Latinos, compared to Whites. But clinical research efforts and data collection have historically lacked diverse representation for various reasons, posing a large risk to these national initiatives in their ability to develop diverse cohorts that adequately represent racial/ethnic minorities. Efforts to reduce disparities and increase diversity in study cohorts have emerged, from patient navigation, to use of mobile technology to collect data, to national consortiums dedicated to including diverse groups, to university training on health disparities. These efforts point to the need for the Cancer Moonshot and precision medicine leaders to develop a multifaceted approach to address disparities in health and healthcare to promote a diverse healthcare workforce, patient-centered care, maintenance of a database of information regarding the state of health disparities, and the institution of measurable goals for improving care across all ethnic groups. If these elements are included, it is possible that the Cancer Moonshot and precision medicine will benefit the entire population of our country.

Population characteristics of golden retriever lifetime study enrollees.

PubMed

Simpson, Melissa; Searfoss, Erin; Albright, Sharon; Brown, Diane E; Wolfe, Barbara; Clark, Nancy K; McCann, Susan E; Haworth, David; Guy, Mike; Page, Rod

2017-01-01

Studying cancer and other diseases poses a problem due to their protracted and multifactorial nature. Prospective studies are useful to investigate chronic disease processes since collection of lifestyle information, exposure data and co-incident health issues are collected before the condition manifests. The Golden Retriever Lifetime Study is one of the first prospective studies following privately-owned dogs throughout life to investigate the incidence and risk factors for disease outcomes, especially cancer.Owners of golden retrievers in the contiguous United States volunteered their dogs in early life. Owners and veterinarians complete online questionnaires about health status and lifestyle; dogs undergo a physical examination and collection of biological samples annually. The data presented summarize the initial study visits and the corresponding questionnaires for 3044 dogs in the cohort. The median age of dogs at enrollment was 14.0 months (interquartile range (IQR): 8-20 months). Approximately half of the population had undergone gonadectomy by their initial study visit. Medical conditions reported at enrollment consisted primarily of integumentary, gastrointestinal and urinary dysfunction. A large majority of the dogs have a record of having received preventive care (vaccines, parasiticides, flea and heartworm prevention) by the time of the initial study visit. Clinical pathology data were unremarkable. This study represents one of the first lifetime observational investigations in veterinary medicine. The population characteristics reported here indicate a healthy cohort of golden retrievers cared for by owners committed to their dogs' health. Data acquired over the study period will provide valuable information about genetic, dietary and environmental risk factors associated with disease in golden retrievers and a framework for future prospective studies in veterinary medicine.

Early dynamical evolution of substructured stellar clusters

NASA Astrophysics Data System (ADS)

Dorval, Julien; Boily, Christian

2015-08-01

It is now widely accepted that stellar clusters form with a high level of substructure (Kuhn et al. 2014, Bate 2009), inherited from the molecular cloud and the star formation process. Evidence from observations and simulations also indicate the stars in such young clusters form a subvirial system (Kirk et al. 2007, Maschberger et al. 2010). The subsequent dynamical evolution can cause important mass loss, ejecting a large part of the birth population in the field. It can also imprint the stellar population and still be inferred from observations of evolved clusters. Nbody simulations allow a better understanding of these early twists and turns, given realistic initial conditions. Nowadays, substructured, clumpy young clusters are usually obtained through pseudo-fractal growth (Goodwin et al. 2004) and velocity inheritance. Such models are visually realistics and are very useful, they are however somewhat artificial in their velocity distribution. I introduce a new way to create clumpy initial conditions through a "Hubble expansion" which naturally produces self consistent clumps, velocity-wise. A velocity distribution analysis shows the new method produces realistic models, consistent with the dynamical state of the newly created cores in hydrodynamic simulation of cluster formation (Klessen & Burkert 2000). I use these initial conditions to investigate the dynamical evolution of young subvirial clusters, up to 80000 stars. I find an overall soft evolution, with hierarchical merging leading to a high level of mass segregation. I investigate the influence of the mass function on the fate of the cluster, specifically on the amount of mass loss induced by the early violent relaxation. Using a new binary detection algorithm, I also find a strong processing of the native binary population.

Direct evidence for radiative charge transfer after inner-shell excitation and ionization of large clusters

NASA Astrophysics Data System (ADS)

Hans, Andreas; Stumpf, Vasili; Holzapfel, Xaver; Wiegandt, Florian; Schmidt, Philipp; Ozga, Christian; Reiß, Philipp; Ben Ltaief, Ltaief; Küstner-Wetekam, Catmarna; Jahnke, Till; Ehresmann, Arno; Demekhin, Philipp V.; Gokhberg, Kirill; Knie, André

2018-01-01

We directly observe radiative charge transfer (RCT) in Ne clusters by dispersed vacuum-ultraviolet photon detection. The doubly ionized Ne2+-{{{N}}{{e}}}n-1 initial states of RCT are populated after resonant 1s-3p photoexcitation or 1s photoionization of Ne n clusters with < n> ≈ 2800. These states relax further producing Ne+-Ne+-{{{N}}{{e}}}n-2 final states, and the RCT photon is emitted. Ab initio calculations assign the observed RCT signal to the{}{{{N}}{{e}}}2+(2{{{p}}}-2{[}1{{D}}]){--}{{{N}}{{e}}}n-1 initial state, while transitions from other possible initial states are proposed to be quenched by competing relaxation processes. The present results are in agreement with the commonly discussed scenario, where the doubly ionized atom in a noble gas cluster forms a dimer which dissipates its vibrational energy on a picosecond timescale. Our study complements the picture of the RCT process in weakly bound clusters, providing information which is inaccessible by charged particle detection techniques.

Evaluation of Event Physical Activity Engagement at an Open Streets Initiative Within a Texas-Mexico Border Town.

PubMed

Salazar-Collier, Cindy Lynn; Reininger, Belinda; Gowen, Rose; Rodriguez, Arturo; Wilkinson, Anna

2018-05-09

Open streets initiatives provide an opportunity to engage in physical activity (PA) freely by temporarily closing streets to motorized traffic. Route counting estimation and event intercept surveys (n = 682) were conducted across 4 CycloBia events in Brownsville, TX, in 2015 to determine sociodemographics, PA engagement at the event, event awareness, and past CycloBia attendance. Cycling was the most commonly observed activity along the route (73.6%) followed by walking (22.9%). Attendees self-reported a median of 120 minutes in PA with 17.3% of attendees meeting recommended weekly PA guidelines at the event. Significant predictors of meeting PA guidelines via event PA engagement were past event attendance, sex, age, and Hispanic ethnicity. Findings suggest that CycloBia reached a large, low-income, predominantly Hispanic population and may be effective in promoting PA. Results help understand the effect of an open streets initiative on attendees living in a midsize, border city.

GROUP INEQUALITY

PubMed Central

Bowles, Samuel; Loury, Glenn C.; Sethi, Rajiv

2014-01-01

We explore the combined effect of segregation in social networks, peer effects, and the relative size of a historically disadvantaged group on the incentives to invest in market-rewarded skills and the dynamics of inequality between social groups. We identify conditions under which group inequality will persist in the absence of differences in ability, credit constraints, or labor market discrimination. Under these conditions, group inequality may be amplified even if initial group differences are negligible. Increases in social integration may destabilize an unequal state and make group equality possible, but the distributional and human capital effects of this depend on the demographic composition of the population. When the size of the initially disadvantaged group is sufficiently small, integration can lower the long-run costs of human capital investment in both groups and result in an increase the aggregate skill share. In contrast, when the initially disadvantaged group is large, integration can induce a fall in the aggregate skill share as the costs of human capital investment rise in both groups. We consider applications to concrete cases and policy implications. PMID:25554727

GROUP INEQUALITY.

PubMed

Bowles, Samuel; Loury, Glenn C; Sethi, Rajiv

2014-02-01

We explore the combined effect of segregation in social networks, peer effects, and the relative size of a historically disadvantaged group on the incentives to invest in market-rewarded skills and the dynamics of inequality between social groups. We identify conditions under which group inequality will persist in the absence of differences in ability, credit constraints, or labor market discrimination. Under these conditions, group inequality may be amplified even if initial group differences are negligible. Increases in social integration may destabilize an unequal state and make group equality possible, but the distributional and human capital effects of this depend on the demographic composition of the population. When the size of the initially disadvantaged group is sufficiently small, integration can lower the long-run costs of human capital investment in both groups and result in an increase the aggregate skill share. In contrast, when the initially disadvantaged group is large, integration can induce a fall in the aggregate skill share as the costs of human capital investment rise in both groups. We consider applications to concrete cases and policy implications.

The second Chicago televised smoking cessation program: a 24-month follow-up.

PubMed Central

Warnecke, R B; Langenberg, P; Wong, S C; Flay, B R; Cook, T D

1992-01-01

OBJECTIVES. As smoking decreases in the population, the remaining smoking population will change, and cessation initiatives will have to incorporate strategies designed for these smokers. METHODS. To study patterns of response to a cessation intervention composed of 20 televised segments and the American Lung Association Freedom from Smoking in 20 Days manual, this study compared cessation rates over 24 months in a cohort of smokers who registered for a cessation program with those in a cohort selected from the smoking population at large. RESULTS. At post intervention, multiple point prevalence of cessation among participants, adjusted for baseline smoking, was 14% among registrants and 6% in the population; at 24 months the adjusted rates were 6% and 2%, respectively. Heavy smokers benefited more than light smokers, and there was a consistent dose-response relationship between extent of exposure to the intervention and cessation. CONCLUSION. The effects of the intervention were strongest for those who read the manual and watched the programs daily. Manual use was important, and those who did not read it did not appear to benefit. Compared to the population and given full participation, heavy smokers benefited more than lighter smokers. PMID:1585964

The prevalence of resonances among large-a transneptunian objects

NASA Astrophysics Data System (ADS)

Gladman, Brett; Volk, Kathryn; Van Laerhoven, Christa

2018-04-01

The detached population consists of transneptunian objects (TNOs) with large semi-major axes and sufficiently high perihelia (roughly q>38 au, but there is no simple cut). However, what constitutes 'large semi-major axis' has been, and continues to be, unclear. Once beyond the apehlia of the classical Kuiper Belt (which extends out to about 60 au), objects with semimajor axes from a=60-150 au can be detached, but there are a reasonable number of objects in this range known to be in mean-motion resonances with Neptune. Beyond a=150 au, however, it is a widely-held belief that resonances become `unimportant', and that a q>38 au cut (or sometimes q>50 au) with a>150 au isolates a set of large semimajor axis detached objects. However, once semimajor axes become this large, the orbit determination of the object discovered near perihelion becomes a much harder task then for low-a TNOs. Because small velocity differences near the perihelion of large-a orbits cause large changes the fitted orbital in semimajor axis, extremely good and long baseline astrometry is required to reduce the semimajor axis uncertainty to be smaller than the few tenths of an astronomical unit widths of mean motion resonances. By carefully analyzing the astrometric data of all known large semimajor axis objects, we show that a very large fraction of the objects are in fact likely in high-order mean-motion resonances with Neptune. This prevealence for actually being resonant with Neptune would imply that hypothesized planets are problematic as they would remove the detached objects from these resonances. Instead, we favor a view in which the large-a population is the surviving remnant of a massive early scattering disk, whose surviving members are sculpted mostly by diffusive gravitational interactions with the four giant planets over the last four gigayears, but whose initial emplacement mechanism (in particular: perihelion lifting mechanism) is still unclear but of critical importance to the early Solar System's evolution.

Significance of the tropical fire ant Solenopsis geminata (hymenoptera: formicidae) as part of the natural enemy complex responsible for successful biological control of many tropical irrigated rice pests.

PubMed

Way, M J; Heong, K L

2009-10-01

The tropical fire ant Solenopsis geminata (Fabricius) often nests very abundantly in the earthen banks (bunds) around irrigated rice fields in the tropics. Where some farmers habitually drain fields to the mud for about 3-4 days, the ants can quickly spread up to about 20 m into the fields where they collect food, including pest prey such as the eggs and young of the apple snail Pomacea caniculata (Lamarck) and insects such as lepidopterous larvae and hoppers, notably Nilaparvata lugens (Stäl) the brown planthopper (Bph) and green leafhoppers Nephotettix spp. Even in drained fields, the activity of S. geminata is restricted by rainfall in the wet season. The relatively few ant workers that forage characteristically into drained fields and on to the transplanted clumps of rice plants (hills) kill the normally few immigrant Bph adults but are initially slower acting than other species of the natural enemy complex. However, larger populations of Bph are fiercely attacked and effectively controlled by rapidly recruited ant workers; whereas, in the absence of the ant, the other natural enemies are inadequate. In normal circumstances, there is no ant recruitment in response to initially small populations of immigrant Bph and no evidence of incompatibility between ant foragers and other natural enemies such as spiders. However, when many ants are quickly and aggressively recruited to attack large populations of Bph, they temporarily displace some spiders from infested hills. It is concluded that, in suitable weather conditions and even when insecticides kill natural enemies within the rice field, periodic drainage that enables S. geminata to join the predator complex is valuable for ant-based control of pests such as snails and Lepidoptera, and especially against relatively large populations of Bph. Drainage practices to benefit ants are fully compatible with recent research, which shows that periodic drainage combats problems of 'yield decline' in intensively irrigated tropical rice and is also needed in South East Asia to make better use of seriously declining water supplies for irrigation.

Does source population size affect performance in new environments?

PubMed Central

Yates, Matthew C; Fraser, Dylan J

2014-01-01

Small populations are predicted to perform poorly relative to large populations when experiencing environmental change. To explore this prediction in nature, data from reciprocal transplant, common garden, and translocation studies were compared meta-analytically. We contrasted changes in performance resulting from transplantation to new environments among individuals originating from different sized source populations from plants and salmonids. We then evaluated the effect of source population size on performance in natural common garden environments and the relationship between population size and habitat quality. In ‘home-away’ contrasts, large populations exhibited reduced performance in new environments. In common gardens, the effect of source population size on performance was inconsistent across life-history stages (LHS) and environments. When transplanted to the same set of new environments, small populations either performed equally well or better than large populations, depending on life stage. Conversely, large populations outperformed small populations within native environments, but only at later life stages. Population size was not associated with habitat quality. Several factors might explain the negative association between source population size and performance in new environments: (i) stronger local adaptation in large populations and antagonistic pleiotropy, (ii) the maintenance of genetic variation in small populations, and (iii) potential environmental differences between large and small populations. PMID:25469166

Different preventions methods lead to different choices? Questions on HIV/AIDS prevention for men who have sex with men and other vulnerable populations.

PubMed

Terto, Veriano

2015-09-01

On the basis of an ethnographic narrative on sexual interactions observed in urban parks in large Brazilian cities, the article discusses the adoption of new strategies and methods for AIDS prevention in vulnerable populations, especially in men who have sex with men (MSM). By following some guiding questions, the text debates when, why, with whom, and in which context the new prevention methods should be adopted. It emphasizes, in agreement to the initial narrative, the importance of taking into account the prevention strategies created by the population itself to manage HIV risk infection. It also addresses how prevention practices and messages are adapted and recreated by individuals and groups in an attempt to suit them to their sexual desires, practices, and choices. In this perspective, the article recommends the inclusion of the experiences and voices of individuals and groups considered vulnerable in the new AIDS prevention methods and programs targeted to them.

Public health consequences on vulnerable populations from acute chemical releases.

PubMed

Ruckart, Perri Zeitz; Orr, Maureen F

2008-07-09

Data from a large, multi-state surveillance system on acute chemical releases were analyzed to describe the type of events that are potentially affecting vulnerable populations (children, elderly and hospitalized patients) in order to better prevent and plan for these types of incidents in the future. During 2003-2005, there were 231 events where vulnerable populations were within ¼ mile of the event and the area of impact was greater than 200 feet from the facility/point of release. Most events occurred on a weekday during times when day care centers or schools were likely to be in session. Equipment failure and human error caused a majority of the releases. Agencies involved in preparing for and responding to chemical emergencies should work with hospitals, nursing homes, day care centers, and schools to develop policies and procedures for initiating appropriate protective measures and managing the medical needs of patients. Chemical emergency response drills should involve the entire community to protect those that may be more susceptible to harm.

Public Health Consequences on Vulnerable Populations from Acute Chemical Releases

PubMed Central

Ruckart, Perri Zeitz; Orr, Maureen F.

2008-01-01

Data from a large, multi-state surveillance system on acute chemical releases were analyzed to describe the type of events that are potentially affecting vulnerable populations (children, elderly and hospitalized patients) in order to better prevent and plan for these types of incidents in the future. During 2003–2005, there were 231 events where vulnerable populations were within ¼ mile of the event and the area of impact was greater than 200 feet from the facility/point of release. Most events occurred on a weekday during times when day care centers or schools were likely to be in session. Equipment failure and human error caused a majority of the releases. Agencies involved in preparing for and responding to chemical emergencies should work with hospitals, nursing homes, day care centers, and schools to develop policies and procedures for initiating appropriate protective measures and managing the medical needs of patients. Chemical emergency response drills should involve the entire community to protect those that may be more susceptible to harm. PMID:21572842

Genome-wide association study identifies three key loci for high mesocarp oil content in perennial crop oil palm.

PubMed

Teh, Chee-Keng; Ong, Ai-Ling; Kwong, Qi-Bin; Apparow, Sukganah; Chew, Fook-Tim; Mayes, Sean; Mohamed, Mohaimi; Appleton, David; Kulaveerasingam, Harikrishna

2016-01-08

GWAS in out-crossing perennial crops is typically limited by insufficient marker density to account for population diversity and effects of population structure resulting in high false positive rates. The perennial crop oil palm is the most productive oil crop. We performed GWAS for oil-to-dry-mesocarp content (O/DM) on 2,045 genotyped tenera palms using 200K SNPs that were selected based on the short-range linkage disequilibrium distance, which is inherent with long breeding cycles and heterogeneous breeding populations. Eighty loci were significantly associated with O/DM (p ≤ 10(-4)) and three key signals were found. We then evaluated the progeny of a Deli x AVROS breeding trial and a 4% higher O/DM was observed amongst those having the beneficial genotypes at two of the three key loci (p < 0.05). We have initiated MAS and large-scale planting of elite dura and pisifera parents to generate the new commercial tenera palms with higher O/DM potential.

Kinetics and dynamics of near-resonant vibrational energy transfer in gas ensembles of atmospheric interest

NASA Astrophysics Data System (ADS)

McCaffery, Anthony J.

2018-03-01

This study of near-resonant, vibration-vibration (V-V) gas-phase energy transfer in diatomic molecules uses the theoretical/computational method, of Marsh & McCaffery (Marsh & McCaffery 2002 J. Chem. Phys. 117, 503 (doi:10.1063/1.1489998)) The method uses the angular momentum (AM) theoretical formalism to compute quantum-state populations within the component molecules of large, non-equilibrium, gas mixtures as the component species proceed to equilibration. Computed quantum-state populations are displayed in a number of formats that reveal the detailed mechanism of the near-resonant V-V process. Further, the evolution of quantum-state populations, for each species present, may be followed as the number of collision cycles increases, displaying the kinetics of evolution for each quantum state of the ensemble's molecules. These features are illustrated for ensembles containing vibrationally excited N2 in H2, O2 and N2 initially in their ground states. This article is part of the theme issue `Modern theoretical chemistry'.

Current & future vulnerability of sarasota county Florida to hurricane storm surge & sea level rise

USGS Publications Warehouse

Frazier, T.; Wood, N.; Yarnal, B.

2008-01-01

Coastal communities in portions of the United States are vulnerable to storm-surge inundation from hurricanes and this vulnerability will likely increase, given predicted rises in sea level from climate change and growing coastal development. In this paper, we provide an overview of research to determine current and future societal vulnerability to hurricane storm-surge inundation and to help public officials and planners integrate these scenarios into their long-range land use plans. Our case study is Sarasota County, Florida, where planners face the challenge of balancing increasing population growth and development with the desire to lower vulnerability to storm surge. Initial results indicate that a large proportion of Sarasota County's residential and employee populations are in areas prone to storm-surge inundation from a Category 5 hurricane. This hazard zone increases when accounting for potential sea-level-rise scenarios, thereby putting additional populations at risk. Subsequent project phases involve the development of future land use and vulnerability scenarios in collaboration with local officials. Copyright ASCE 2008.

Genealogical data in population medical genetics: Field guidelines

PubMed Central

Poletta, Fernando A.; Orioli, Ieda M.; Castilla, Eduardo E.

2014-01-01

This is a guide for fieldwork in Population Medical Genetics research projects. Data collection, handling, and analysis from large pedigrees require the use of specific tools and methods not widely familiar to human geneticists, unfortunately leading to ineffective graphic pedigrees. Initially, the objective of the pedigree must be decided, and the available information sources need to be identified and validated. Data collection and recording by the tabulated method is advocated, and the involved techniques are presented. Genealogical and personal information are the two main components of pedigree data. While the latter is unique to each investigation project, the former is solely represented by gametic links between persons. The triad of a given pedigree member and its two parents constitutes the building unit of a genealogy. Likewise, three ID numbers representing those three elements of the triad is the record field required for any pedigree analysis. Pedigree construction, as well as pedigree and population data analysis, varies according to the pre-established objectives, the existing information, and the available resources. PMID:24764752

Restoration longevity in an Australian Defence Force population.

PubMed

Dawson, A S; Smales, R J

1992-06-01

Replacement of restorations comprises a considerable portion of the work of most dentists. Consequently, factors that affect restoration longevity can influence the pattern of dental practice in a given community. Based on the results of research into treatment provision in the General Dental Service in Scotland, it was considered possible that factors such as the frequency with which patients were examined, and the frequency with which they changed dentists, might influence restoration longevity in other populations. Therefore, the present study was initiated to investigate the effects of these two factors in a population of 100 long-term members of the Royal Australian Air Force. No statistically significant relationship could be found between examination frequency, or frequent changes in dental practitioner, and restoration longevity. It is proposed that the large differences found in restoration longevity between this study and the Scottish study upon which it was based, may be due in part to the differing modes of remuneration of the dentists in the two studies.

The K-KIDS Sample: K Dwarfs within 50 Parsecs and the Search for their Closest Companions with CHIRON

NASA Astrophysics Data System (ADS)

Paredes-Alvarez, Leonardo; Nusdeo, Daniel Anthony; Henry, Todd J.; Jao, Wei-Chun; Gies, Douglas R.; White, Russel; RECONS Team

2017-01-01

To understand fundamental aspects of stellar populations, astronomers need carefully vetted, volume-complete samples. In our K-KIDS effort, our goal is to survey a large sample of K dwarfs for their "kids", companions that may be stellar, brown dwarf, or planetary in nature. Four surveys for companions orbiting an initial set of 1048 K dwarfs with declinations between +30 and -30 have begun. Companions are being detected with separations less than 1 AU out to 10000 AU. Fortuitously, the combination of Hipparcos and Gaia DR1 astrometry with optical photometry from APASS and infrared photometry from 2MASS now allows us to create an effectively volume-complete sample of K dwarfs to a horizon of 50 pc. This sample facilitates rigorous studies of the luminosity and mass functions, as well as comprehensive mapping of the companions orbiting K dwarfs that have never before been possible.Here we present two important results. First, we find that our initial sample of ~1000 K dwarfs can be expanded to 2000-3000 stars in what is an effectively volume-complete sample. This population is sufficiently large to provide superb statistics on the outcomes of star and planet formation processes. Second, initial results from our high-precision radial velocity survey of K dwarfs with the CHIRON spectrograph on the CTIO/SMARTS 1.5m reveal its short-term precision and indicate that stellar, brown dwarf and Jovian planets will be detectable. We present radial velocity curves for an inital sample of 8 K dwarfs with V = 7-10 using cross-correlation techniques on R=80,000 spectra, and illustrate the stability of CHIRON over hours, days, and weeks. Ultimately, the combination of all four surveys will provide an unprecedented portrait of K dwarfs and their kids.This effort has been supported by the NSF through grants AST-1412026 and AST-1517413, and via observations made possible by the SMARTS Consortium

Overview of the 2006 MILAGRO Campaign in Mexico City: Transport and Transformation of Emissions from a Megacity

NASA Astrophysics Data System (ADS)

Molina, L.; MILAGRO Science Team

2009-04-01

Megacities (metropolitan areas with population over 10 million) and large urban centers present a major challenge for the global environment. Population growth, increasing motorization and industrialization have resulted in a higher demand for energy, greater use of fossil fuels, and more emission of pollutants into the atmosphere. As a result, air pollution has become not only one of the central environmental problems of the century, but also presents serious consequences to human health and ecosystems and economic costs to society. MILAGRO (Megacity Initiative: Local and Global Research Observations) is the first international effort to study the impact of air pollutants generated and exported by megacity. The Mexico City Metropolitan Area (MCMA) - one of the largest megacities in the world - was selected as the initial case study for MILAGRO. The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, complemented by meteorological forecasting and numerical simulations. Together, these research observations have provided the most comprehensive characterization of Mexico City's urban and regional air pollution that will take years to analyze and evaluate fully. Initial analysis of the data is focused on understanding meteorology, emissions, urban and regional photochemistry, aerosol evolution and radiative effects - spanning the urban to regional scale transition. Many interesting aspects of atmospheric chemistry in and near the MCMA are emerging and have already added significantly to our understanding of the chemical and physical properties of the city's reactive atmosphere and the regional impacts. The information can be useful for decision-makers in Mexico in developing air quality management strategies as well as provide insights to air pollution problems in other megacities and large urban centers around the world.

The Effect of Defects on the Fatigue Initiation Process in Two P/M Superalloys.

DTIC Science & Technology

1980-09-01

determine the effect of Sdfect size, shape, and population on the fatigue initiation process in two high strength P/M superalloys, AF-l5 and AF2-lDA. The...to systematically determine the effects of defect size, shape, and population on fatigue. It is true that certain trends have been established...to determine the relative effects of defect size, shape, and population on the crack initiation life of a representative engineering material

NMR study of methane + ethane structure I hydrate decomposition.

PubMed

Dec, Steven F; Bowler, Kristen E; Stadterman, Laura L; Koh, Carolyn A; Sloan, E Dendy

2007-05-24

The thermally activated decomposition of methane + ethane structure I hydrate was studied with use of 13C magic-angle spinning (MAS) NMR as a function of composition and temperature. The observed higher decomposition rate of large sI cages initially filled with ethane gas can be described in terms of a model where a distribution of sI unit cells exists such that a particular unit cell contains zero, one, or two methane molecules in the unit cell; this distribution of unit cells is combined to form the observed equilibrium composition. In this model, unit cells with zero methane molecules are the least stable and decompose more rapidly than those populated with one or two methane molecules leading to the observed overall faster decomposition rate of the large cages containing ethane molecules.

Resolving the Milky Way and Nearby Galaxies with WFIRST

NASA Astrophysics Data System (ADS)

Kalirai, Jasonjot

High-resolution studies of nearby stellar populations have served as a foundation for our quest to understand the nature of galaxies. Today, studies of resolved stellar populations constrain fundamental relations -- such as the initial mass function of stars, the time scales of stellar evolution, the timing of mass loss and amount of energetic feedback, the color-magnitude relation and its dependency on age and metallicity, the stellar-dark matter connection in galaxy halos, and the build up of stellar populations over cosmic time -- that represent key ingredients in our prescription to interpret light from the Universe and to measure the physical state of galaxies. More than in any other area of astrophysics, WFIRST will yield a transformative impact in measuring and characterizing resolved stellar populations in the Milky Way and nearby galaxies. The proximity and level of detail that such populations need to be studied at directly map to all three pillars of WFIRST capabilities - sensitivity from a 2.4 meter space based telescope, resolution from 0.1" pixels, and large 0.3 degree field of view from multiple detectors. Our WFIRST GO Science Investigation Team (F) will develop three WFIRST (notional) GO programs related to resolved stellar populations to fully stress WFIRST's Wide Field Instrument. The programs will include a Survey of the Milky Way, a Survey of Nearby Galaxy Halos, and a Survey of Star-Forming Galaxies. Specific science goals for each program will be validated through a wide range of observational data sets, simulations, and new algorithms. As an output of this study, our team will deliver optimized strategies and tools to maximize stellar population science with WFIRST. This will include: new grids of IR-optimized stellar evolution and synthetic spectroscopic models; pipelines and algorithms for optimal data reduction at the WFIRST sensitivity and pixel scale; wide field simulations of MW environments and galaxy halos; cosmological simulations of nearby galaxy halos matched to WFIRST observations; strategies and automated algorithms to find substructure and dwarf galaxies in WFIRST IR data sets; and documentation. Our team will work closely with the WFIRST Science Center to translate our notional programs into inputs that can help achieve readiness for WFIRST science operations. This includes building full observing programs with target definitions, observing sequences, scheduling constraints, data processing needs, and calibration requirements. Our team has been chosen carefully. Team members are leading scientists in stellar population work that will be a core science theme for WFIRST and are also involved in all large future astronomy projects that will operate in the WFIRST era. The team is intentionally small, and each member will "own" significant science projects. The team will aggressively advocate for WFIRST through innovative initiatives. The team is also diverse in geographical location, observers and theorists, and gender.

Differential Regulation of Mouse B Cell Development by Transforming Growth Factor β1

PubMed Central

Kaminski, Denise A.; Letterio, John J.; Burrows, Peter D.

2002-01-01

Transforming growth factor β (TGFβ) can inhibit the in vitro proliferation, survival and differentiation of B cell progenitors, mature B lymphocytes and plasma cells. Here we demonstrate unexpected, age-dependent reductions in the bone marrow (BM) B cell progenitors and immature B cells in TGFβ1-/- mice. To evaluate TGFβ responsiveness during normal B lineage development, cells were cultured in interleukin 7 (IL7)±TGFβ. Picomolar doses of TGFβ1 reduced pro-B cell recoveries at every timepoint. By contrast, the pre-B cells were initially reduced in number, but subsequently increased compared to IL7 alone, resulting in a 4-fold increase in the growth rate for the pre-B cell population. Analysis of purified BM sub-populations indicated that pro-B cells and the earliest BP1- pre-B cells were sensitive to the inhibitory effects of TGFβ1. However, the large BP1+ pre-B cells, although initially reduced, were increased in number at days 5 and 7 of culture. These results indicate that TGFβ1 is important for normal B cell development in vivo, and that B cell progenitors are differentially affected by the cytokine according to their stage of differentiation. PMID:12739785

End-of-life matters in chronic renal failure.

PubMed

Berman, Nathaniel

2014-12-01

The population considered eligible for dialysis has expanded dramatically over the past 4 decades, so that a significant proportion of patients receiving renal replacement therapy are elderly, frail and infirm. These patients have an extremely limited life expectancy and suffer from significant symptom burden, similar to patients with other end-stage organ failure or cancer. As dialysis has been offered more broadly, it is now initiated earlier than in decades past, further adding to cost and patient burden. The trend toward more expansive and intensive care has not been corroborated by robust data. In response, an increasing number of studies has focused on establishing reasonable limits to renal replacement therapy. Multiple authors have explored the role of conservative kidney management for high-risk dialysis patients as an alternative to dialysis, which may offer similar survival and improved quality of life in certain populations. For those who chose dialysis, deferring initiation until the patient becomes symptomatic may be a reasonable. Evidence-based symptom management guidelines for dialysis patients remain largely absent, with few proven approaches. Hospice and palliative care resources remain underutilized. For a subset of dialysis patients, palliative care and conservative kidney management are appropriate and underutilized. http://links.lww.com/COSPC/A8

The reduction of health care costs associated with alcoholism treatment: a 14-year longitudinal study.

PubMed

Holder, H D; Blose, J O

1992-07-01

This study utilized two separate research designs to examine whether the initiation of alcoholism treatment is associated with a change in overall medical care cost in a population of alcoholics enrolled under a health plan sponsored by a large midwestern manufacturing corporation. In the longest longitudinal study of alcoholism treatment costs to date, a review of claims filed from 1974 to 1987 identified 3,729 alcoholics (3,068 of whom received treatment and 661 of whom did not). In one design, a time-series analysis found that following treatment initiation the total health care costs of treated alcoholics--including the cost of alcoholism treatment--declined by 23% to 55% from their highest pretreatment levels. Costs for identified but untreated alcoholics rose following identification. In a second design, analysis of variance was used to control for group differences including pretreatment health status and age. This analysis indicated that the posttreatment costs of treated alcoholics were 24% lower than comparable costs for untreated alcoholics. The study provides considerable evidence that alcoholism treatment can reduce overall medical costs in a heterogeneous alcoholic population (white collar/blue collar; fee-for-service/HMO).

The effect of seasonal birth pulses on pathogen persistence in wild mammal populations.

PubMed

Peel, A J; Pulliam, J R C; Luis, A D; Plowright, R K; O'Shea, T J; Hayman, D T S; Wood, J L N; Webb, C T; Restif, O

2014-07-07

The notion of a critical community size (CCS), or population size that is likely to result in long-term persistence of a communicable disease, has been developed based on the empirical observations of acute immunizing infections in human populations, and extended for use in wildlife populations. Seasonal birth pulses are frequently observed in wildlife and are expected to impact infection dynamics, yet their effect on pathogen persistence and CCS have not been considered. To investigate this issue theoretically, we use stochastic epidemiological models to ask how host life-history traits and infection parameters interact to determine pathogen persistence within a closed population. We fit seasonal birth pulse models to data from diverse mammalian species in order to identify realistic parameter ranges. When varying the synchrony of the birth pulse with all other parameters being constant, our model predicted that the CCS can vary by more than two orders of magnitude. Tighter birth pulses tended to drive pathogen extinction by creating large amplitude oscillations in prevalence, especially with high demographic turnover and short infectious periods. Parameters affecting the relative timing of the epidemic and birth pulse peaks determined the intensity and direction of the effect of pre-existing immunity in the population on the pathogen's ability to persist beyond the initial epidemic following its introduction.

Initial characterisation of low and high seed dormancy populations of Lolium rigidum produced by repeated selection.

PubMed

Goggin, Danica E; Emery, R J Neil; Powles, Stephen B; Steadman, Kathryn J

2010-10-15

The physiological and biochemical bases of seed dormancy in Lolium rigidum (annual ryegrass) are largely unknown, and study of this process is complicated by the outcrossing nature of the species and the strong influence of environment on seed dormancy. In order to identify heritable biochemical factors contributing to seed dormancy in L. rigidum, seeds from a field-collected population were used to select sub-populations with consistently low or high seed dormancy over four generations. Low-dormancy seeds showed constitutive alpha-amylase activity prior to imbibition, higher concentrations of polyphenols and cis-zeatin, and lower abscisic acid and cis-zeatin riboside concentrations than high-dormancy seeds. Selection for high dormancy was associated with a reduction in response to dark-stratification for 21d at 20 degrees C (an effective means of releasing dormancy in the original, unselected population) over successive generations, but fluridone remained effective in breaking dormancy. Crossing of low- and high-dormancy populations indicated that dormancy level was not dependent upon the maternal genotype of the seed, and that the constitutive alpha-amylase activity and high seed anthocyanin concentrations characteristic of the low-dormancy populations were not correlated to high basal germination ability. Copyright (c) 2010 Elsevier GmbH. All rights reserved.

The effect of seasonal birth pulses on pathogen persistence in wild mammal populations

PubMed Central

Peel, A. J.; Pulliam, J. R. C.; Luis, A. D.; Plowright, R. K.; O'Shea, T. J.; Hayman, D. T. S.; Wood, J. L. N.; Webb, C. T.; Restif, O.

2014-01-01

The notion of a critical community size (CCS), or population size that is likely to result in long-term persistence of a communicable disease, has been developed based on the empirical observations of acute immunizing infections in human populations, and extended for use in wildlife populations. Seasonal birth pulses are frequently observed in wildlife and are expected to impact infection dynamics, yet their effect on pathogen persistence and CCS have not been considered. To investigate this issue theoretically, we use stochastic epidemiological models to ask how host life-history traits and infection parameters interact to determine pathogen persistence within a closed population. We fit seasonal birth pulse models to data from diverse mammalian species in order to identify realistic parameter ranges. When varying the synchrony of the birth pulse with all other parameters being constant, our model predicted that the CCS can vary by more than two orders of magnitude. Tighter birth pulses tended to drive pathogen extinction by creating large amplitude oscillations in prevalence, especially with high demographic turnover and short infectious periods. Parameters affecting the relative timing of the epidemic and birth pulse peaks determined the intensity and direction of the effect of pre-existing immunity in the population on the pathogen's ability to persist beyond the initial epidemic following its introduction. PMID:24827436

School collective occupation movements and substance use among adolescents: A school-level panel design.

PubMed

Castillo-Carniglia, Alvaro; Kaufman, Jay S; Pizarro, Esteban; Marín, José D; Wintemute, Garen; Cerdá, Magdalena

2017-07-01

Recently, social movements across the world have demanded reforms to education systems and other institutions. Although such movements have affected large numbers of people across multiple countries, we know little about the impacts they have had on population health. We focus on one example: the massive strikes and collective occupation of secondary schools across Chile, which occurred contemporaneously with a large increase in marijuana use among students in this age group. We aimed to evaluate the causal effects that the 2011 Chilean school strikes had on adolescent substance use, including the initiation of marijuana use and the use of alcohol and marijuana. School-level, aggregated panel design using data from the National Drug Surveys among Secondary Students from 2005 to 2015 for students in grades 9-12. We used a fixed-effects difference-in-difference model to estimate the effect of school occupations on prevalence of self-reported indicators of drug use. Reported marijuana use doubled between 2009 and 2013 among Chilean adolescents. After controlling for secular trends in outcomes and for school characteristics, there was no evidence of increased marijuana initiation, alcohol and marijuana use, or of an increase in heavy use among adolescents being directly attributable to school strikes and occupations in 2011. The 2011 Occupy school movement in Chile had no detectable causal effect on substance use among Chilean adolescents. The increase in marijuana use from 2009 to 2013 seems to be part of broader social changes occurring among the school-age population. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of temperature and moisture on Mormon cricket reproduction with implications for responses to climate change.

PubMed

Srygley, Robert B

2014-06-01

During the last decade, populations of flightless Mormon crickets Anabrus simplex (Orthoptera: Tettigoniidae) increased suddenly over vast areas of the Western United States, suggesting that climate is an important factor driving outbreaks. Moreover summer temperatures are predicted to increase and precipitation is expected to decrease in most areas of the U.S. Great Basin, but little is known of the response of Mormon crickets to changes in temperature and soil moisture. In a laboratory study, we varied ambient temperature and lighting and measured the propensity of mating pairs to mate, and the proportion of eggs that developed into embryos. We found that reproduction was optimal when ambient temperature reached 30°C and the insects were beneath broad-spectrum lights such that maternal body and soil temperatures reached 35°C. Fewer eggs that developed fully were laid when maternal body and soil temperatures reached 30°C or 37-39°C. We also varied initial soil moisture from 0% to 100% saturated and found that more eggs reached embryonic diapause when initial soil moisture was 25% or 50% of saturated volume. However more of the developed eggs hatched when treated in summer soils with 0-25% of saturated moisture. We conclude that small changes in temperature had large effects on reproduction, whereas large changes in moisture had very small effects on reproduction. This is the first report of Mormon crickets mating in a laboratory setting and laying eggs that hatched, facilitating further research on the role of maternal and embryonic environments in changes in population size. Published by Elsevier Ltd.

Health Games: A Key Component for the Evolution of Wellness Programs.

PubMed

Lenihan, David

2012-06-01

Healthcare cost growth has been a major concern for both governments and employers. Considerable efforts have been made to "bend the trend" or find ways to control costs. At the highest levels, this has been the move from indemnity care models to managed care and then to consumer-directed health models using Healthcare Reimbursement Accounts and Healthcare Spending Accounts in plan designs. Accompanying this move in plan design has been an effort to get the consumer/patient/employee more engaged and responsible for his or her health expenditures, health decision-making, and activities. Consumers have gone through the phases of health being doctor-centric (indemnity care model), to health plan-centric (managed care models), to consumer-centric (consumer-directed health models). There is currently a need to incorporate wellness into the equation. Simply put, wellness is intended to keep people out of the health system by reducing the risk factors that would put them into the system in the first place. This includes things like smoking cessation, exercise, weight management, nutrition, and other factors over which individuals have a significant level of control over, as well as condition management such as medication adherence, and condition monitoring (such as glucose monitoring for diabetics). Wellness will become increasingly more common for major buyers, initially large self-funded employers and then health plans that will offer it as a part of their overall Plan Design and Administration services. Wellness initiatives will also be offered by Federal and State governments and will include programs for the elderly and at-risk populations as well as for the general population. The measure of success of wellness programs to actually "bend the trend" will be engagement. How large a piece of the population can be captured and retained will be the critical metric for success…and metrics require real data and will be used by the entire healthcare value-chain to measure efficacy and efficiency of "wellness spending."

Ultracool dwarf benchmarks with Gaia primaries

NASA Astrophysics Data System (ADS)

Marocco, F.; Pinfield, D. J.; Cook, N. J.; Zapatero Osorio, M. R.; Montes, D.; Caballero, J. A.; Gálvez-Ortiz, M. C.; Gromadzki, M.; Jones, H. R. A.; Kurtev, R.; Smart, R. L.; Zhang, Z.; Cabrera Lavers, A. L.; García Álvarez, D.; Qi, Z. X.; Rickard, M. J.; Dover, L.

2017-10-01

We explore the potential of Gaia for the field of benchmark ultracool/brown dwarf companions, and present the results of an initial search for metal-rich/metal-poor systems. A simulated population of resolved ultracool dwarf companions to Gaia primary stars is generated and assessed. Of the order of ˜24 000 companions should be identifiable outside of the Galactic plane (|b| > 10 deg) with large-scale ground- and space-based surveys including late M, L, T and Y types. Our simulated companion parameter space covers 0.02 ≤ M/M⊙ ≤ 0.1, 0.1 ≤ age/Gyr ≤ 14 and -2.5 ≤ [Fe/H] ≤ 0.5, with systems required to have a false alarm probability <10-4, based on projected separation and expected constraints on common distance, common proper motion and/or common radial velocity. Within this bulk population, we identify smaller target subsets of rarer systems whose collective properties still span the full parameter space of the population, as well as systems containing primary stars that are good age calibrators. Our simulation analysis leads to a series of recommendations for candidate selection and observational follow-up that could identify ˜500 diverse Gaia benchmarks. As a test of the veracity of our methodology and simulations, our initial search uses UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey to select secondaries, with the parameters of primaries taken from Tycho-2, Radial Velocity Experiment, Large sky Area Multi-Object fibre Spectroscopic Telescope and Tycho-Gaia Astrometric Solution. We identify and follow up 13 new benchmarks. These include M8-L2 companions, with metallicity constraints ranging in quality, but robust in the range -0.39 ≤ [Fe/H] ≤ +0.36, and with projected physical separation in the range 0.6 < s/kau < 76. Going forward, Gaia offers a very high yield of benchmark systems, from which diverse subsamples may be able to calibrate a range of foundational ultracool/sub-stellar theory and observation.

Outcomes of Elderly Patients after Predialysis Vascular Access Creation

PubMed Central

Lee, Timmy; Thamer, Mae; Zhang, Yi; Zhang, Qian

2015-01-01

Uniform vascular access guidelines for elderly patients may be inappropriate because of the competing risk of death, high rate of arteriovenous fistula (AVF) maturation failure, and poor vascular access outcomes in this population. However, the outcomes in elderly patients with advanced CKD who receive permanent vascular access before dialysis initiation are unclear. We identified a large nationally representative cohort of 3418 elderly patients (aged ≥70 years) with CKD undergoing predialysis AVF or arteriovenous graft (AVG) creation from 2004 to 2009, and assessed the frequencies of dialysis initiation, death before dialysis initiation, and dialysis-free survival for 2 years after vascular access creation. In all, 67% of patients with predialysis AVF and 71% of patients with predialysis AVG creation initiated dialysis within 2 years of access placement, but the overall risk of dialysis initiation was modified by patient age and race. Only one half of patients initiated dialysis with a functioning AVF or AVG; 46.8% of AVFs were created <90 days before dialysis initiation. Catheter dependence at dialysis initiation was more common in patients receiving predialysis AVF than in patients receiving AVG (46.0% versus 28.5%; P<0.001). In conclusion, most elderly patients with advanced CKD who received predialysis vascular access creation initiated dialysis within 2 years. As a consequence of late predialysis placement or maturation failure, almost one half of patients receiving AVFs initiated dialysis with a catheter. Insertion of an AVG closer to dialysis initiation may serve as a “catheter-sparing” approach and allow delay of permanent access placement in selected elderly patients with CKD. PMID:25855782

Outcomes of Elderly Patients after Predialysis Vascular Access Creation.

PubMed

Lee, Timmy; Thamer, Mae; Zhang, Yi; Zhang, Qian; Allon, Michael

2015-12-01

Uniform vascular access guidelines for elderly patients may be inappropriate because of the competing risk of death, high rate of arteriovenous fistula (AVF) maturation failure, and poor vascular access outcomes in this population. However, the outcomes in elderly patients with advanced CKD who receive permanent vascular access before dialysis initiation are unclear. We identified a large nationally representative cohort of 3418 elderly patients (aged ≥ 70 years) with CKD undergoing predialysis AVF or arteriovenous graft (AVG) creation from 2004 to 2009, and assessed the frequencies of dialysis initiation, death before dialysis initiation, and dialysis-free survival for 2 years after vascular access creation. In all, 67% of patients with predialysis AVF and 71% of patients with predialysis AVG creation initiated dialysis within 2 years of access placement, but the overall risk of dialysis initiation was modified by patient age and race. Only one half of patients initiated dialysis with a functioning AVF or AVG; 46.8% of AVFs were created <90 days before dialysis initiation. Catheter dependence at dialysis initiation was more common in patients receiving predialysis AVF than in patients receiving AVG (46.0% versus 28.5%; P<0.001). In conclusion, most elderly patients with advanced CKD who received predialysis vascular access creation initiated dialysis within 2 years. As a consequence of late predialysis placement or maturation failure, almost one half of patients receiving AVFs initiated dialysis with a catheter. Insertion of an AVG closer to dialysis initiation may serve as a "catheter-sparing" approach and allow delay of permanent access placement in selected elderly patients with CKD. Copyright © 2015 by the American Society of Nephrology.

Research-IQ: Development and Evaluation of an Ontology-anchored Integrative Query Tool

PubMed Central

Borlawsky, Tara B.; Lele, Omkar; Payne, Philip R. O.

2011-01-01

Investigators in the translational research and systems medicine domains require highly usable, efficient and integrative tools and methods that allow for the navigation of and reasoning over emerging large-scale data sets. Such resources must cover a spectrum of granularity from bio-molecules to population phenotypes. Given such information needs, we report upon the initial design and evaluation of an ontology-anchored integrative query tool, Research-IQ, which employs a combination of conceptual knowledge engineering and information retrieval techniques to enable the intuitive and rapid construction of queries, in terms of semi-structured textual propositions, that can subsequently be applied to integrative data sets. Our initial results, based upon both quantitative and qualitative evaluations of the efficacy and usability of Research-IQ, demonstrate its potential to increase clinical and translational research throughput. PMID:21821150

Spatio-Temporal Patterning in Primary Motor Cortex at Movement Onset.

PubMed

Best, Matthew D; Suminski, Aaron J; Takahashi, Kazutaka; Brown, Kevin A; Hatsopoulos, Nicholas G

2017-02-01

Voluntary movement initiation involves the engagement of large populations of motor cortical neurons around movement onset. Despite knowledge of the temporal dynamics that lead to movement, the spatial structure of these dynamics across the cortical surface remains unknown. In data from 4 rhesus macaques, we show that the timing of attenuation of beta frequency local field potential oscillations, a correlate of locally activated cortex, forms a spatial gradient across primary motor cortex (MI). We show that these spatio-temporal dynamics are recapitulated in the engagement order of ensembles of MI neurons. We demonstrate that these patterns are unique to movement onset and suggest that movement initiation requires a precise spatio-temporal sequential activation of neurons in MI. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Application of person-centered analytic methodology in longitudinal research: exemplars from the Women's Health Initiative Clinical Trial data.

PubMed

Zaslavsky, Oleg; Cochrane, Barbara B; Herting, Jerald R; Thompson, Hilaire J; Woods, Nancy F; Lacroix, Andrea

2014-02-01

Despite the variety of available analytic methods, longitudinal research in nursing has been dominated by use of a variable-centered analytic approach. The purpose of this article is to present the utility of person-centered methodology using a large cohort of American women 65 and older enrolled in the Women's Health Initiative Clinical Trial (N = 19,891). Four distinct trajectories of energy/fatigue scores were identified. Levels of fatigue were closely linked to age, socio-demographic factors, comorbidities, health behaviors, and poor sleep quality. These findings were consistent regardless of the methodological framework. Finally, we demonstrated that energy/fatigue levels predicted future hospitalization in non-disabled elderly. Person-centered methods provide unique opportunities to explore and statistically model the effects of longitudinal heterogeneity within a population. © 2013 Wiley Periodicals, Inc.

Emergence of a global science-business initiative for ocean stewardship.

PubMed

Österblom, Henrik; Jouffray, Jean-Baptiste; Folke, Carl; Rockström, Johan

2017-08-22

The ocean represents a fundamental source of micronutrients and protein for a growing world population. Seafood is a highly traded and sought after commodity on international markets, and is critically dependent on healthy marine ecosystems. A global trend of wild stocks being overfished and in decline, as well as multiple sustainability challenges associated with a rapid growth of aquaculture, represent key concerns in relation to the United Nations Sustainable Development Goals. Existing efforts aimed to improve the sustainability of seafood production have generated important progress, primarily at the local and national levels, but have yet to effectively address the global challenges associated with the ocean. This study highlights the importance of transnational corporations in enabling transformative change, and thereby contributes to advancing the limited understanding of large-scale private actors within the sustainability science literature. We describe how we engaged with large seafood producers to coproduce a global science-business initiative for ocean stewardship. We suggest that this initiative is improving the prospects for transformative change by providing novel links between science and business, between wild-capture fisheries and aquaculture, and across geographical space. We argue that scientists can play an important role in facilitating change by connecting knowledge to action among global actors, while recognizing risks associated with such engagement. The methods developed through this case study contribute to identifying key competences in sustainability science and hold promises for other sectors as well.

Emergence of a global science–business initiative for ocean stewardship

PubMed Central

Jouffray, Jean-Baptiste; Folke, Carl; Rockström, Johan

2017-01-01

The ocean represents a fundamental source of micronutrients and protein for a growing world population. Seafood is a highly traded and sought after commodity on international markets, and is critically dependent on healthy marine ecosystems. A global trend of wild stocks being overfished and in decline, as well as multiple sustainability challenges associated with a rapid growth of aquaculture, represent key concerns in relation to the United Nations Sustainable Development Goals. Existing efforts aimed to improve the sustainability of seafood production have generated important progress, primarily at the local and national levels, but have yet to effectively address the global challenges associated with the ocean. This study highlights the importance of transnational corporations in enabling transformative change, and thereby contributes to advancing the limited understanding of large-scale private actors within the sustainability science literature. We describe how we engaged with large seafood producers to coproduce a global science–business initiative for ocean stewardship. We suggest that this initiative is improving the prospects for transformative change by providing novel links between science and business, between wild-capture fisheries and aquaculture, and across geographical space. We argue that scientists can play an important role in facilitating change by connecting knowledge to action among global actors, while recognizing risks associated with such engagement. The methods developed through this case study contribute to identifying key competences in sustainability science and hold promises for other sectors as well. PMID:28784792

Experimental test of an eco-evolutionary dynamic feedback loop between evolution and population density in the green peach aphid.

PubMed

Turcotte, Martin M; Reznick, David N; Daniel Hare, J

2013-05-01

An eco-evolutionary feedback loop is defined as the reciprocal impacts of ecology on evolutionary dynamics and evolution on ecological dynamics on contemporary timescales. We experimentally tested for an eco-evolutionary feedback loop in the green peach aphid, Myzus persicae, by manipulating initial densities and evolution. We found strong evidence that initial aphid density alters the rate and direction of evolution, as measured by changes in genotype frequencies through time. We also found that evolution of aphids within only 16 days, or approximately three generations, alters the rate of population growth and predicts density compared to nonevolving controls. The impact of evolution on population dynamics also depended on density. In one evolution treatment, evolution accelerated population growth by up to 10.3% at high initial density or reduced it by up to 6.4% at low initial density. The impact of evolution on population growth was as strong as or stronger than that caused by a threefold change in intraspecific density. We found that, taken together, ecological condition, here intraspecific density, alters evolutionary dynamics, which in turn alter concurrent population growth rate (ecological dynamics) in an eco-evolutionary feedback loop. Our results suggest that ignoring evolution in studies predicting population dynamics might lead us to over- or underestimate population density and that we cannot predict the evolutionary outcome within aphid populations without considering population size.

Ecology of bison, elk, and vegetation in an arid ecosystem

USGS Publications Warehouse

Schoenecker, Kathryn A.

2012-01-01

Herbivory has profound effects on vegetation production and structure in many different plant communities. The influence of herbivory on plants and ultimately ecosystem processes is shaped by the types of plants consumed, the intensity of herbivory, the evolutionary history of grazing, and the availability of water and nutrients to plants. The effect of ungulate herbivores on vegetation is of great interest to ecologists, land managers and agriculturalists. In addition, the Department of Interior recently established a Bison Conservation Initiative to provide for the conservation and restoration of North American plains- and wood bison, which includes establishing new populations and expanding existing populations. The San Luis Valley, Colorado, is being considered as a potential location for a bison conservation herd. Resource managers need to know the vegetation impacts of adding a second large ungulate to a system that already has elk.

The stability of colorectal cancer mathematical models

NASA Astrophysics Data System (ADS)

Khairudin, Nur Izzati; Abdullah, Farah Aini

2013-04-01

Colorectal cancer is one of the most common types of cancer. To better understand about the kinetics of cancer growth, mathematical models are used to provide insight into the progression of this natural process which enables physicians and oncologists to determine optimal radiation and chemotherapy schedules and develop a prognosis, both of which are indispensable for treating cancer. This thesis investigates the stability of colorectal cancer mathematical models. We found that continuous saturating feedback is the best available model of colorectal cancer growth. We also performed stability analysis. The result shows that cancer progress in sequence of genetic mutations or epigenetic which lead to a very large number of cells population until become unbounded. The cell population growth initiate and its saturating feedback is overcome when mutation changes causing the net per-capita growth rate of stem or transit cells exceed critical threshold.

Population Dynamics of Early Human Migration in Britain

PubMed Central

Vahia, Mayank N.; Ladiwala, Uma; Mahathe, Pavan; Mathur, Deepak

2016-01-01

Background Early human migration is largely determined by geography and human needs. These are both deterministic parameters when small populations move into unoccupied areas where conflicts and large group dynamics are not important. The early period of human migration into the British Isles provides such a laboratory which, because of its relative geographical isolation, may allow some insights into the complex dynamics of early human migration and interaction. Method and Results We developed a simulation code based on human affinity to habitable land, as defined by availability of water sources, altitude, and flatness of land, in choosing the path of migration. Movement of people on the British island over the prehistoric period from their initial entry points was simulated on the basis of data from the megalithic period. Topographical and hydro-shed data from satellite databases was used to define habitability, based on distance from water bodies, flatness of the terrain, and altitude above sea level. We simulated population movement based on assumptions of affinity for more habitable places, with the rate of movement tempered by existing populations. We compared results of our computer simulations with genetic data and show that our simulation can predict fairly accurately the points of contacts between different migratory paths. Such comparison also provides more detailed information about the path of peoples’ movement over ~2000 years before the present era. Conclusions We demonstrate an accurate method to simulate prehistoric movements of people based upon current topographical satellite data. Our findings are validated by recently-available genetic data. Our method may prove useful in determining early human population dynamics even when no genetic information is available. PMID:27148959

Preventing Childhood Malaria in Africa by Protecting Adults from Mosquitoes with Insecticide-Treated Nets

PubMed Central

Killeen, Gerry F; Smith, Tom A; Ferguson, Heather M; Mshinda, Hassan; Abdulla, Salim; Lengeler, Christian; Kachur, Steven P

2007-01-01

Background Malaria prevention in Africa merits particular attention as the world strives toward a better life for the poorest. Insecticide-treated nets (ITNs) represent a practical means to prevent malaria in Africa, so scaling up coverage to at least 80% of young children and pregnant women by 2010 is integral to the Millennium Development Goals (MDG). Targeting individual protection to vulnerable groups is an accepted priority, but community-level impacts of broader population coverage are largely ignored even though they may be just as important. We therefore estimated coverage thresholds for entire populations at which individual- and community-level protection are equivalent, representing rational targets for ITN coverage beyond vulnerable groups. Methods and Findings Using field-parameterized malaria transmission models, we show that high (80% use) but exclusively targeted coverage of young children and pregnant women (representing <20% of the population) will deliver limited protection and equity for these vulnerable groups. In contrast, relatively modest coverage (35%–65% use, with this threshold depending on ecological scenario and net quality) of all adults and children, rather than just vulnerable groups, can achieve equitable community-wide benefits equivalent to or greater than personal protection. Conclusions Coverage of entire populations will be required to accomplish large reductions of the malaria burden in Africa. While coverage of vulnerable groups should still be prioritized, the equitable and communal benefits of wide-scale ITN use by older children and adults should be explicitly promoted and evaluated by national malaria control programmes. ITN use by the majority of entire populations could protect all children in such communities, even those not actually covered by achieving existing personal protection targets of the MDG, Roll Back Malaria Partnership, or the US President's Malaria Initiative. PMID:17608562

The very young resolved stellar populations around stripped-envelope supernovae

NASA Astrophysics Data System (ADS)

Maund, Justyn R.

2018-05-01

The massive star origins for Type IIP supernovae (SNe) have been established through direct detection of their red supergiants progenitors in pre-explosion observations; however, there has been limited success in the detection of the progenitors of H-deficient SNe. The final fate of more massive stars, capable of undergoing a Wolf-Rayet phase, and the origins of Type Ibc SNe remain debated, including the relative importance of single massive star progenitors or lower mass stars stripped in binaries. We present an analysis of the ages and spatial distributions of massive stars around the sites of 23 stripped-envelope SNe, as observed with the Hubble Space Telescope, to probe the possible origins of the progenitors of these events. Using a Bayesian stellar populations analysis scheme, we find characteristic ages for the populations observed within 150 pc of the target Type IIb, Ib, and Ic SNe to be log (t) = 7.20, 7.05, and 6.57, respectively. The Type Ic SNe in the sample are nearly all observed within 100 pc of young, dense stellar populations. The environment around SN 2002ap is an important exception both in terms of age and spatial properties. These findings may support the hypothesis that stars with Minit > 30 M⊙ produce a relatively large proportion of Type Ibc SNe, and that these SN subtypes arise from progressively more massive progenitors. Significantly higher extinctions are derived towards the populations hosting these SNe than previously used in analysis of constraints from pre-explosion observations. The large initial masses inferred for the progenitors are in stark contrast with the low ejecta masses estimated from SN light curves.

Linkage and retention in HCV care for HIV-infected populations: early data from the DAA era.

PubMed

Sacks-Davis, Rachel; Doyle, Joseph S; Rauch, Andri; Beguelin, Charles; Pedrana, Alisa E; Matthews, Gail V; Prins, Maria; van der Valk, Marc; Klein, Marina B; Saeed, Sahar; Lacombe, Karine; Chkhartishvili, Nikoloz; Altice, Frederick L; Hellard, Margaret E

2018-04-01

There is currently no published data on the effectiveness of DAA treatment for elimination of HCV infection in HIV-infected populations at a population level. However, a number of relevant studies and initiatives are emerging. This research aims to report cascade of care data for emerging HCV elimination initiatives and studies that are currently being evaluated in HIV/HCV co-infected populations in the context of implementation science theory. HCV elimination initiatives and studies in HIV co-infected populations that are currently underway were identified. Context, intervention characteristics and cascade of care data were synthesized in the context of implementation science frameworks. Seven HCV elimination initiatives and studies were identified in HIV co-infected populations, mainly operating in high-income countries. Four were focused mainly on HCV elimination in HIV-infected gay and bisexual men (GBM), and three included a combination of people who inject drugs (PWID), GBM and other HIV-infected populations. None were evaluating treatment delivery in incarcerated populations. Overall, HCV RNA was detected in 4894 HIV-infected participants (range within studies: 297 to 994): 48% of these initiated HCV treatment (range: 21% to 85%; within studies from a period where DAAs were broadly available the total is 57%, range: 36% to 74%). Among studies with treatment completion data, 96% of 1109 initiating treatment completed treatment (range: 94% to 99%). Among those who could be assessed for sustained virological response at 12 weeks (SVR12), 1631 of 1757 attained SVR12 (93%, range: 86% to 98%). Early results from emerging research on HCV elimination in HIV-infected populations suggest that HCV treatment uptake is higher than reported levels prior to DAA treatment availability, but approximately half of patients remain untreated. These results are among diagnosed populations and additional effort is required to increase diagnosis rates. Among those who have initiated treatment, completion and SVR rates are promising. More data are required in order to evaluate the effectiveness of these elimination programmes in the long term, assess which intervention components are effective, and whether they need to be tailored to particular population groups. © 2018 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of the International AIDS Society.

Demographic and health attributes of the Nahua, initial contact population of the Peruvian Amazon.

PubMed

Culqui, Dante R; Ayuso-Alvarez, Ana; Munayco, Cesar V; Quispe-Huaman, Carlos; Mayta-Tristán, Percy; Campos, Juan de Mata Donado

2016-01-01

We present the case of the Nahua population of Santa Rosa de Serjali, Peruvian Amazon's population, considered of initial contact. This population consists of human groups that for a long time decided to live in isolation, but lately have begun living a more sedentary lifestyle and in contact with Western populations. There are two fully identified initial contact groups in Peru: the Nahua and the Nanti. The health statistics of the Nahua are scarce. This study offers an interpretation of demographic and epidemiological indicators of the Nahua people, trying to identify if a certain degree of health vulnerability exists. We performed a cross sectional study, and after analyzing their health indicators, as well as the supplemental qualitative analysis of the population, brought us to conclude that in 2006, the Nahua, remained in a state of health vulnerability.

Human influences on trophic cascades along rocky shores

USGS Publications Warehouse

Lindberg, D.R.; Estes, J.A.; Warheit, K.I.

1998-01-01

A three-trophic-level interaction among American Black Oystercatchers (Haematopus bachmani), limpets (Lottia spp.), and erect fleshy algae in rocky intertidal communities of central and southern California was documented via manipulative and 'natural' experiments. Removal of the territorial limpet (Lottia gigantea) initially caused large increases in the percent cover of erect fleshy algae, followed by a more gradual increase in density of small limpets (Lottia spp.) and a decline in algal cover. Algal cover increased following the removal of small limpets at the sites from which L. gigantea had been removed earlier, thus demonstrating that the large and small limpets had similar inhibitory effects on plant populations. A comparison of sites with and without oyster-catchers showed that L. gigantea occupied substrate inclinations in proportion to their availability at sites where oystercatchers were rare, whereas the distribution of L. gigantea was skewed toward vertically inclined substrates where oystercatchers were common. Survival rates of limpets translocated to horizontal and vertical substrates were similar in sites lacking oystercatcher predation, but were much lower on horizontal substrates where oystercatchers were common. Our results are consistent with those from several prior studies in demonstrating that shorelines frequented by humans typically lack oystercatchers. Humans also exploit L. gigantea and reduce populations to low densities of small individuals. These findings may explain why the midlittoral zone of rocky intertidal communities in western North America are so often dominated by high population densities of small limpets.

Close to home: an analysis of the relationship between location of residence and location of injury.

PubMed

Haas, Barbara; Doumouras, Aristithes G; Gomez, David; de Mestral, Charles; Boyes, Donald M; Morrison, Laurie; Nathens, Avery B

2015-04-01

Injury surveillance is critical in identifying the need for targeted prevention initiatives. Understanding the geographic distribution of injuries facilitates matching prevention programs with the population most likely to benefit. At the population level, however, the geographic site of injury is rarely known, leading to the use of location of residence as a surrogate. To determine the accuracy of this approach, we evaluated the relationship between the site of injury and of residence over a large geographic area. Data were derived from a population-based, prehospital registry of persons meeting triage criteria for major trauma. Patients dying at the scene or transported to the hospital were included. Distance between locations of residence and of injury was calculated using geographic information system network analysis. Among 3,280 patients (2005-2010), 88% were injured within 10 miles of home (median, 0.2 miles). There were significant differences in distance between residence and location of injury based on mechanism of injury, age, and hospital disposition. The large majority of injuries involving children, the elderly, pedestrians, cyclists, falls, and assaults occurred less than 10 miles from the patient's residence. Only 77% of motor vehicle collision occurred within 10 miles of the patient's residence. Although the majority of patients are injured less than 10 miles from their residence, the probability of injury occurring "close to home" depends on patient and injury characteristics. Epidemiologic study, level III.

Variation in host resistance and pathogen selective value in the interaction between Pinus sylvestris and the fungus Crumenulopsis sororia.

PubMed

Ennos, R A; McConnell, K C

2003-09-01

There have been many studies of plant pathogen evolution in systems showing gene-for-gene control of host resistance. However little is known about situations, exemplified by Scots pine, Pinus sylvestris, and its fungal pathogen Crumenulopsis sororia, where variation in host resistance is quantitative. In a field experiment genetically marked isolates of C. sororia from three natural populations were reciprocally inoculated on 1- and 2-year-old branch tissue of P. sylvestris in the three sites from which they had been collected. Quantitative variation in host resistance was measured by comparing the performance of the same inocula on different host populations, individuals and tissues. The selective value of isolates derived from different populations was estimated by comparing the frequency of genotypes in lesion re-isolations with those in the initial inoculum mixtures. Host resistance varied significantly among populations, individuals within populations and between 1- and 2-year-old branch tissue of P. sylvestris. Large differences in the relative selective values of C. sororia isolates from different populations were detected. The selective value of pathogens was independent of the host population on which they were inoculated. However, their selective value did depend on the age of the tissue on which they grew. The implications of these results for modelling evolution in pathogen-host interactions that lack gene-for-gene determination of host resistance are discussed.

Development of integrated surveillance systems for the management of tuberculosis in New Zealand wildlife.

PubMed

Anderson, D P; Ramsey, D S L; de Lisle, G W; Bosson, M; Cross, M L; Nugent, G

2015-06-01

Disease surveillance for the management of bovine tuberculosis (TB) in New Zealand has focussed, to a large extent, on the development of tools specific for monitoring Mycobacterium bovis infection in wildlife. Diagnostic techniques have been modified progressively over 30 years of surveillance of TB in wildlife, from initial characterisation of gross TB lesions in a variety of wildlife, through development of sensitive culture techniques to identify viable mycobacteria, to molecular identification of individual M. bovis strains. Of key importance in disease surveillance has been the elucidation of the roles that different wildlife species play in the transmission of infection, specifically defining brushtail possums (Trichosurus vulpecula) as true maintenance hosts compared to those that are predominantly spillover hosts, but which may serve as useful sentinel species to indicate TB persistence. Epidemiological modelling has played a major role in TB surveillance, initially providing the theoretical support for large-scale possum population control and setting targets at which control effort should be deployed to ensure disease eradication. As TB prevalence in livestock and wildlife declined throughout the 2000s, more varied field tools were developed to gather surveillance data from the diminishing possum populations, and to provide information on changing TB prevalence. Accordingly, ever more precise (but disparate) surveillance information began to be integrated into multi-faceted decision-assist models to support TB management decisions, particularly to provide informed parameters at which control effort could be halted, culminating in the Proof of Freedom modelling framework that now allows an area to be declared TB-free within chosen confidence limits. As New Zealand moves from large-scale TB control to regional eradication of disease in the coming years, further integrative models will need to be developed to support management decisions, based on combined field data of possum and TB prevalence, sentinel information, risk assessment in relation to financial benefits, and changing political and environmental needs.

Conditional nonlinear optimal perturbations based on the particle swarm optimization and their applications to the predictability problems

NASA Astrophysics Data System (ADS)

Zheng, Qin; Yang, Zubin; Sha, Jianxin; Yan, Jun

2017-02-01

In predictability problem research, the conditional nonlinear optimal perturbation (CNOP) describes the initial perturbation that satisfies a certain constraint condition and causes the largest prediction error at the prediction time. The CNOP has been successfully applied in estimation of the lower bound of maximum predictable time (LBMPT). Generally, CNOPs are calculated by a gradient descent algorithm based on the adjoint model, which is called ADJ-CNOP. This study, through the two-dimensional Ikeda model, investigates the impacts of the nonlinearity on ADJ-CNOP and the corresponding precision problems when using ADJ-CNOP to estimate the LBMPT. Our conclusions are that (1) when the initial perturbation is large or the prediction time is long, the strong nonlinearity of the dynamical model in the prediction variable will lead to failure of the ADJ-CNOP method, and (2) when the objective function has multiple extreme values, ADJ-CNOP has a large probability of producing local CNOPs, hence making a false estimation of the LBMPT. Furthermore, the particle swarm optimization (PSO) algorithm, one kind of intelligent algorithm, is introduced to solve this problem. The method using PSO to compute CNOP is called PSO-CNOP. The results of numerical experiments show that even with a large initial perturbation and long prediction time, or when the objective function has multiple extreme values, PSO-CNOP can always obtain the global CNOP. Since the PSO algorithm is a heuristic search algorithm based on the population, it can overcome the impact of nonlinearity and the disturbance from multiple extremes of the objective function. In addition, to check the estimation accuracy of the LBMPT presented by PSO-CNOP and ADJ-CNOP, we partition the constraint domain of initial perturbations into sufficiently fine grid meshes and take the LBMPT obtained by the filtering method as a benchmark. The result shows that the estimation presented by PSO-CNOP is closer to the true value than the one by ADJ-CNOP with the forecast time increasing.

Mozambique.

PubMed

1985-05-01

Mozambique's population characteristics, geographical features, political conditions, history, government, foreign relations, and economy are profiled. Mozambique's population of 13.4 million (1984) is composed mainly of indigenous tribal groups and about 10,000 Europeans, 35,000 Euro-Africans, and 15,000 Indians. 50% of the population practices traditional religious, 30% is Muslim, and the remaining 15% is Christian. The official language is Portuguese. The literacy rate is 14%, current school attendance is 40%, the infant mortality rate is 115, and life expectancy is 47 years. Topographic features include a large coastal area of lowlands and a western plateau region. The climate is tropical or subtropical, and rainfall is unpredictable and in some areas, scarce. The area was initially inhabited by hunting and gathering groups and, subsequently, invaded by waves of Bantu farmers. The Portugese began establishing trading posts in the area in the early 1500s, gradually expanded their influence, and later allowed companies, mostly British owned, to administer large tracts of the country. The companies derived large profits either by operating railroad lines betwen Mozambique's ports and large cities in countries to the west of Mozambique or by supporting African labor for mines and plantations in other parts of Africa. In 1984, a number of African resistance movements united to form the Front for the Liberation of Mozambique, and in 1975, following a decade of sporadic warfare, Mozambique won its independence and established a 1-party socialist government. The new country was faced with serious economic problems and a shortage of skilled labor. During the colonial era, no infrastructure was built for the delivery of health and education services, the economy was geared to provide services to the European population and industrialization was discouraged. Many Europeans fled when independence was declared, and the country was left to confront its economic problems with a largely untrained and uneducated labor force. Shortly after independence, the economy was further disrupted by UN sanctions to close Rhodesia's borders and by the discontinuation of the gold for labor arrangement with South Africa. The new government nationalized most economic activities in the country; however, since 1983, the government allow small private enterprises to operate and encourages foreign investment. 85% of the population is engaged in agriculture, and most are subsistence farmers. The government places a high priority on agricultural development. In 1983, the estimated gross national product (GNP) was US$2.7 billion, and per capita income was US$220. Exports and imports amounted respectively to US$132 million and US$636 million. The government initially followed a Soviet oriented foreign policy, but in recent years, a more independent stance was adopted. Between 1977-82, there was a hostile relationship between the US and Mozambique; however, in 1983 diplomatic relations were reestablished, and in 1985 the US provided the country with US$50-70 million in food and economic assistance. Since 1980, the country's development has been hindered by the acitivities of the Mozambican National Resistance (RENAMO), an armed insurgency force organized by Rhodesia's Ian Smith regime and later financed by South Africa. Although South Africa and Mozambique mutally agreed in 1984 to refrain from providing assistance to groups seeking to disrupt each other's governments, private citizens in South Africa continue to finance RENAMO activities.

Framing Innovation: The Impact of the Superintendent's Technology Infrastructure Decisions on the Acceptance of Large-Scale Technology Initiatives

ERIC Educational Resources Information Center

Arnold, Erik P.

2014-01-01

A multiple-case qualitative study of five school districts that had implemented various large-scale technology initiatives was conducted to describe what superintendents do to gain acceptance of those initiatives. The large-scale technology initiatives in the five participating districts included 1:1 District-Provided Device laptop and tablet…

Mass-loss rates of cool stars

NASA Astrophysics Data System (ADS)

Katrien Els Decin, Leen

2015-08-01

Over much of the initial mass function, stars lose a significant fraction of their mass through a stellar wind during the late stages of their evolution when being a (super)giant star. As of today, we can not yet predict the mass-loss rate during the (super)giant phase for a given star with specific stellar parameters from first principles. This uncertainty directly impacts the accuracy of current stellar evolution and population synthesis models that predict the enrichment of the interstellar medium by these stellar winds. Efforts to establish the link between the initial physical and chemical conditions at stellar birth and the mass-loss rate during the (super)giant phase have proceeded on two separate tracks: (1) more detailed studies of the chemical and morpho-kinematical structure of the stellar winds of (super)giant stars in our own Milky Way by virtue of the proximity, and (2) large scale and statistical studies of a (large) sample of stars in other galaxies (such as the LMC and SMC) and globular clusters eliminating the uncertainty on the distance estimate and providing insight into the dependence of the mass-loss rate on the metallicity. In this review, I will present recent results of both tracks, will show how recent measurements confirm (some) theoretical predictions, but also how results from the first track admonish of common misconceptions inherent in the often more simplified analysis used to analyse the large samples from track 2.

Synchronous Pulmonary Malignancies: Atypical Presentation of Mantle Cell Lymphoma Masking a Lung Malignancy

PubMed Central

Masha, Luke; Zinchuk, Andrey; Boosalis, Valia

2015-01-01

We present a case of a pleural space malignancy masked by an atypical presentation of mantle cell lymphoma. Our patient presented with a large pleural effusion and right sided pleural studding, initially attributed to a new diagnosis of mantle cell lymphoma. Rare atypical epithelial cells were also seen amongst the clonal population of lymphocytes. The patient lacked systemic manifestations of mantle cell lymphoma and did not improve with chemotherapy. A pleural biopsy ultimately revealed the presence of an undifferentiated carcinoma, favoring a lung primary. A discussion of synchronous pleural space malignancies involving lymphomas is given. PMID:26500732

Synchronous Pulmonary Malignancies: Atypical Presentation of Mantle Cell Lymphoma Masking a Lung Malignancy.

PubMed

Masha, Luke; Zinchuk, Andrey; Boosalis, Valia

2015-09-07

We present a case of a pleural space malignancy masked by an atypical presentation of mantle cell lymphoma. Our patient presented with a large pleural effusion and right sided pleural studding, initially attributed to a new diagnosis of mantle cell lymphoma. Rare atypical epithelial cells were also seen amongst the clonal population of lymphocytes. The patient lacked systemic manifestations of mantle cell lymphoma and did not improve with chemotherapy. A pleural biopsy ultimately revealed the presence of an undifferentiated carcinoma, favoring a lung primary. A discussion of synchronous pleural space malignancies involving lymphomas is given.

Grand unification scale primordial black holes: consequences and constraints.

PubMed

Anantua, Richard; Easther, Richard; Giblin, John T

2009-09-11

A population of very light primordial black holes which evaporate before nucleosynthesis begins is unconstrained unless the decaying black holes leave stable relics. We show that gravitons Hawking radiated from these black holes would source a substantial stochastic background of high frequency gravititational waves (10(12) Hz or more) in the present Universe. These black holes may lead to a transient period of matter-dominated expansion. In this case the primordial Universe could be temporarily dominated by large clusters of "Hawking stars" and the resulting gravitational wave spectrum is independent of the initial number density of primordial black holes.

Reaching the Unreachable: Novel Approaches to Telemedicine Screening of Underserved Populations for Vitreoretinal Disease.

PubMed

Murchison, Ann P; Haller, Julia A; Mayro, Eileen; Hark, Lisa; Gower, Emily; Huisingh, Carrie; Rhodes, Lindsay; Friedman, David S; Lee, David J; Lam, Byron L

2017-07-01

Telemedicine involves electronic communication between a physician in one location and a patient in another location to provide remote medical care. Ophthalmologists are increasingly employing telemedicine, particularly in retinal disease screening and monitoring. Telemedicine has been utilized to decrease barriers to care and yield greater patient satisfaction and lower costs, while maintaining high sensitivity and specificity. This review discusses common patient barriers to eye care, innovative approaches to retinal disease screening and monitoring using telemedicine, and eye care policy initiatives needed to enact large-scale telemedicine eye disease screening programs.

Update on ONC's Substellar IMF: A Second Peak in the Brown Dwarf Regime

NASA Astrophysics Data System (ADS)

Drass, Holger; Bayo, A.; Chini, R.; Haas, M.

2017-06-01

The Orion Nebular Cluster (ONC) has become the prototype cluster for studying the Initial Mass Function (IMF). In a deep JHK survey of the ONC with HAWK-I we detected a large population of 900 Brown Dwarfs and Planetary Mass Object candidates presenting a pronounced second peak in the substellar IMF. One of the most obvious issues of this result is the verification of cluster membership. The analysis so far was mainly based on statistical consideration. In this presentation I will show the results from using different high-resolution extinction map to determine the ONC membership.

Outlining the Ancestry Landscape of Colombian Admixed Populations

PubMed Central

Ossa, Humberto; Aquino, Juliana; Pereira, Rui; Ibarra, Adriana; Ossa, Rafael H; Pérez, Luz Adriana; Granda, Juan David; Lattig, Maria Claudia; Groot, Helena; Fagundes de Carvalho, Elizeu; Gusmão, Leonor

2016-01-01

The ancestry of the Colombian population comprises a large number of well differentiated Native communities belonging to diverse linguistic groups. In the late fifteenth century, a process of admixture was initiated with the arrival of the Europeans, and several years later, Africans also became part of the Colombian population. Therefore, the genepool of the current Colombian population results from the admixture of Native Americans, Europeans and Africans. This admixture occurred differently in each region of the country, producing a clearly stratified population. Considering the importance of population substructure in both clinical and forensic genetics, we sought to investigate and compare patterns of genetic ancestry in Colombia by studying samples from Native and non-Native populations living in its 5 continental regions: the Andes, Caribe, Amazonia, Orinoquía, and Pacific regions. For this purpose, 46 AIM-Indels were genotyped in 761 non-related individuals from current populations. Previously published genotype data from 214 Colombian Natives from five communities were used for population comparisons. Significant differences were observed between Native and non-Native populations, among non-Native populations from different regions and among Native populations from different ethnic groups. The Pacific was the region with the highest African ancestry, Amazonia harboured the highest Native ancestry and the Andean and Orinoquían regions showed the highest proportion of European ancestry. The Andean region was further sub-divided into 6 sub-regions: North East, Central West, Central East, West, South West and South East. Among these regions, the South West region showed a significantly lower European admixture than the other regions. Hardy-Weinberg equilibrium and variance values of ancestry among individuals within populations showed a potential stratification of the Pacific population. PMID:27736937

Conditional Release Placements of Insanity Acquittees in Oregon: 2012-2014.

PubMed

Novosad, David; Banfe, Shelley; Britton, Juliet; Bloom, Joseph D

2016-03-01

Between January 1, 2012 and December 31, 2014, there was a large population (N = 200) of insanity acquittees placed on conditional release (CR) in the state of Oregon. This article looks at the demographic and system characteristics of this large group of individuals. The authors then focus on the initial housing placement and what happens to individuals after their release in relation to their housing placement. In Oregon, insanity acquittees are either conditionally released directly by the court or placed in the hospital prior to potential CR by a supervising board. In general, once CR occurs, individuals tend to stay in their initial placement without moving to less structured levels of care, raising concerns about transinstitutionalization. This is especially true for individuals released to the most structured living arrangement (secure residential treatment facility). Those individuals who are conditionally released to less structured settings have a higher rate of revocation back to the hospital. Those individuals who do move to less structured levels of care usually have longer hospital stays and start off in more structured levels of care to start their CR. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Challenges for Multilevel Health Disparities Research in a Transdisciplinary Environment

PubMed Central

Holmes, John H.; Lehman, Amy; Hade, Erinn; Ferketich, Amy K.; Sarah, Gehlert; Rauscher, Garth H.; Abrams, Judith; Bird, Chloe E.

2008-01-01

Numerous factors play a part in health disparities. Although health disparities are manifested at the level of the individual, other contexts should be considered when investigating the associations of disparities with clinical outcomes. These contexts include families, neighborhoods, social organizations, and healthcare facilities. This paper reports on health disparities research as a multilevel research domain from the perspective of a large national initiative. The Centers for Population Health and Health Disparities (CPHHD) program was established by the NIH to examine the highly dimensional, complex nature of disparities and their effects on health. Because of its inherently transdisciplinary nature, the CPHHD program provides a unique environment in which to perform multilevel health disparities research. During the course of the program, the CPHHD centers have experienced challenges specific to this type of research. The challenges were categorized along three axes: sources of subjects and data, data characteristics, and multilevel analysis and interpretation. The CPHHDs collectively offer a unique example of how these challenges are met; just as importantly, they reveal a broad range of issues that health disparities researchers should consider as they pursue transdisciplinary investigations in this domain, particularly in the context of a large team science initiative. PMID:18619398

Associations between a voluntary restaurant menu designation initiative and patron purchasing behavior.

PubMed

Sosa, Erica T; Biediger-Friedman, Lesli; Banda, Martha

2014-03-01

Restaurant initiatives provide an efficient opportunity to impact large numbers of patrons. The purpose of this study is to measure patron purchasing behaviors during the ¡Por Vida! menu designation initiative. This study used a cross-sectional design and survey data to assess 23 restaurants throughout Bexar County and 152 restaurant patrons. The Patron Awareness Questionnaire assessed if patrons noticed the logo; believed nutrition, cost, and taste were important in making purchasing decisions; and purchased a ¡Por Vida! item. Descriptive statistics, Spearman correlations, and logistic regression were used to analyze the data. Most (93.4%) patrons considered taste very important when deciding what to eat. Cost was very important to 63.8% and nutrition was very important to 55.9% of the sample. The strongest predictors of purchasing a ¡Por Vida! item were the patrons' ages being between 18 and 35 years (odds ratio = 1.474; confidence interval = 0.017, 0.812; p < .05) and if patrons saw the logo (odds ratio = 4.327; confidence interval = 1.696-11.036; p < .01). Menu logo designation initiatives can potentially influence patron purchasing behaviors among a segment of the population when the logo is visible.

Corporate social responsibility initiatives addressing social exclusion in Bangladesh.

PubMed

Werner, Wendy J

2009-08-01

The private sector is often seen as a driver of exclusionary processes rather than a partner in improving the health and welfare of socially-excluded populations. However, private-sector initiatives and partnerships- collectively labelled corporate social responsibility (CSR) initiatives-may be able to positively impact social status, earning potential, and access to services and resources for socially-excluded populations. This paper presents case studies of CSR projects in Bangladesh that are designed to reduce social exclusion among marginalized populations and explores whether CSR initiatives can increase economic and social capabilities to reduce exclusion. The examples provide snapshots of projects that (a) increase job-skills and employment opportunities for women, disabled women, and rehabilitated drug-users and (b) provide healthcare services to female workers and their communities. The CSR case studies cover a limited number of people but characteristics and practices replicable and scaleable across different industries, countries, and populations are identified. Common success factors from the case studies form the basis for recommendations to design and implement more CSR initiatives targeting socially-excluded groups. The analysis found that CSR has potential for positive and lasting impact on developing countries, especifically on socially-excluded populations. However, there is a need for additional monitoring and critical evaluation.

Evaluation of BRCA1 and BRCA2 mutation prevalence, risk prediction models and a multistep testing approach in French‐Canadian families with high risk of breast and ovarian cancer

PubMed Central

Simard, Jacques; Dumont, Martine; Moisan, Anne‐Marie; Gaborieau, Valérie; Vézina, Hélène; Durocher, Francine; Chiquette, Jocelyne; Plante, Marie; Avard, Denise; Bessette, Paul; Brousseau, Claire; Dorval, Michel; Godard, Béatrice; Houde, Louis; Joly, Yann; Lajoie, Marie‐Andrée; Leblanc, Gilles; Lépine, Jean; Lespérance, Bernard; Malouin, Hélène; Parboosingh, Jillian; Pichette, Roxane; Provencher, Louise; Rhéaume, Josée; Sinnett, Daniel; Samson, Carolle; Simard, Jean‐Claude; Tranchant, Martine; Voyer, Patricia; BRCAs, INHERIT; Easton, Douglas; Tavtigian, Sean V; Knoppers, Bartha‐Maria; Laframboise, Rachel; Bridge, Peter; Goldgar, David

2007-01-01

Background and objective In clinical settings with fixed resources allocated to predictive genetic testing for high‐risk cancer predisposition genes, optimal strategies for mutation screening programmes are critically important. These depend on the mutation spectrum found in the population under consideration and the frequency of mutations detected as a function of the personal and family history of cancer, which are both affected by the presence of founder mutations and demographic characteristics of the underlying population. The results of multistep genetic testing for mutations in BRCA1 or BRCA2 in a large series of families with breast cancer in the French‐Canadian population of Quebec, Canada are reported. Methods A total of 256 high‐risk families were ascertained from regional familial cancer clinics throughout the province of Quebec. Initially, families were tested for a panel of specific mutations known to occur in this population. Families in which no mutation was identified were then comprehensively tested. Three algorithms to predict the presence of mutations were evaluated, including the prevalence tables provided by Myriad Genetics Laboratories, the Manchester Scoring System and a logistic regression approach based on the data from this study. Results 8 of the 15 distinct mutations found in 62 BRCA1/BRCA2‐positive families had never been previously reported in this population, whereas 82% carried 1 of the 4 mutations currently observed in ⩾2 families. In the subset of 191 families in which at least 1 affected individual was tested, 29% carried a mutation. Of these 27 BRCA1‐positive and 29 BRCA2‐positive families, 48 (86%) were found to harbour a mutation detected by the initial test. Among the remaining 143 inconclusive families, all 8 families found to have a mutation after complete sequencing had Manchester Scores ⩾18. The logistic regression and Manchester Scores provided equal predictive power, and both were significantly better than the Myriad Genetics Laboratories prevalence tables (p<0.001). A threshold of Manchester Score ⩾18 provided an overall sensitivity of 86% and a specificity of 82%, with a positive predictive value of 66% in this population. Conclusion In this population, a testing strategy with an initial test using a panel of reported recurrent mutations, followed by full sequencing in families with Manchester Scores ⩾18, represents an efficient test in terms of overall cost and sensitivity. PMID:16905680

Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

PubMed

Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T J

2016-01-01

Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term.

Human-mediated and natural dispersal of an invasive fish in the eastern Great Lakes.

PubMed

Johansson, Mattias L; Dufour, Bradley A; Wellband, Kyle W; Corkum, Lynda D; MacIsaac, Hugh J; Heath, Daniel D

2018-06-01

The globally invasive Round Goby (Neogobius melanostomus) was introduced to the Great Lakes around 1990, spreading widely and becoming the dominant benthic fish in many areas. The speed and scope of this invasion is remarkable and calls into question conventional secondary spread models and scenarios. We utilized nine microsatellites to identify large-scale genetic structure in Round Goby populations in the eastern Great Lakes, and assessed the role of colonization vs. secondary transport and dispersal in developing this structure. We identified three clusters, corresponding with Lake Huron, eastern Lake Erie, and western Lake Erie plus eastern Lake Ontario, along with three highly divergent populations. Bottleneck analysis identified founder effects in two divergent populations. Regression analyses of isolation by distance and allelic richness vs. distance from the initial invasion site were consistent with limited migration. However, some populations in eastern Lake Erie and Lake Ontario showed anomalously low genetic distance from the original site of colonization, consistent with secondary transport of large numbers of individuals via ballast water. We conclude that genetic structure of Round Goby in the Great Lakes principally resulted from long-distance secondary transport via ballast water with additional movement of individual via bait buckets and natural dispersal. The success of Round Gobies represents an interesting model for colonization characterization; however, those same attributes present significant challenges for conservation and fisheries management. Current management likely prevents many new species from arriving in the Great Lakes, but fails to address the transport of species within the lakes after they arrive; this is an issue of clear and pressing importance.

Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation

PubMed Central

Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T. J.

2016-01-01

Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term. PMID:27018998

Initial digital vasculitis in a large multicenter cohort of childhood-onset systemic lupus erythematosus.

PubMed

Sakamoto, Ana Paula; Silva, Clovis Artur; Silva, Marco Felipe Castro da; Lopes, Anandreia Simões; Russo, Gleice Clemente Souza; Sallum, Adriana Maluf Elias; Kozu, Katia; Bonfá, Eloisa; Saad-Magalhães, Claudia; Pereira, Rosa Maria Rodrigues; Len, Claudio Arnaldo; Terreri, Maria Teresa

To assess clinical digital vasculitis (DV) as an initial manifestation of childhood-onset systemic lupus erythematosus (cSLE) within a large population. Multicenter cross-sectional study including 852 cSLE patients (ACR criteria) followed in ten Pediatric Rheumatology centers in São Paulo State, Brazil. DV was observed in 25/852 (3%) cSLE patients. Periungual hemorrhage was diagnosed in 12 (48%), periungual infarction in 7 (28%), tip finger ulceration in 4 (16%), painful nodules in 1 (4%) and gangrene in 1 (4%). A poor outcome, with digital resorption, occurred in 5 (20%). Comparison of patients with and without DV revealed higher frequency of malar rash (80% vs. 53%, p=0.008), discoid rash (16% vs. 4%, p=0.017), photosensitivity (76% vs. 45%, p=0.002) and other cutaneous vasculitides (80% vs. 19%, p<0.0001), whereas the frequency of overall constitutional features (32% vs. 61%, p=0.003), fever (32% vs. 56%, p=0.020) and hepatomegaly (4% vs. 23%, p=0.026) were lower in these patients. Frequency of female gender, severe multi-organ involvement, autoantibodies profile and low complement were alike in both groups (p>0.05). SLEDAI-2K median, DV descriptor excluded, was significantly lower in patients with DV compared to those without this manifestation [10 (0-28) vs. 14 (0-58), p=0.004]. Visceral vasculitis or death were not observed in this cSLE cohort. The frequency of cyclophosphamide use (0% vs. 18%, p=0.014) was significantly lower in the DV group. Our large multicenter study identified clinical DV as one of the rare initial manifestation of active cSLE associated with a mild multisystemic disease, in spite of digital resorption in some of these patients. Copyright © 2017. Published by Elsevier Editora Ltda.

Predictors of viral suppression and rebound among HIV-positive men who have sex with men in a large multi-site Canadian cohort.

PubMed

Tanner, Zachary; Lachowsky, Nathan; Ding, Erin; Samji, Hasina; Hull, Mark; Cescon, Angela; Patterson, Sophie; Chia, Jason; Leslie, Alia; Raboud, Janet; Loutfy, Mona; Cooper, Curtis; Klein, Marina; Machouf, Nima; Tsoukas, Christos; Montaner, Julio; Hogg, Robert S

2016-10-21

Gay, bisexual and other men who have sex with men (MSM) are disproportionately affected by HIV in Canada. Combination antiretroviral therapy has been shown to dramatically decrease progression to AIDS, premature death and HIV transmission. However, there are no comprehensive data regarding combination antiretroviral therapy outcomes among this population. We sought to identify socio-demographic and clinical correlates of viral suppression and rebound. Our analysis included MSM participants in the Canadian Observational Cohort, a multi-site cohort of HIV-positive adults from Canada's three most populous provinces, aged ≥18 years who first initiated combination antiretroviral therapy between 2000 and 2011. We used accelerated failure time models to identify factors predicting time to suppression (2 measures <50 copies/mL ≥30 days apart) and subsequent rebound (2 measures >200 copies/mL ≥30 days apart). Of 2,858 participants, 2,448 (86 %) achieved viral suppression in a median time of 5 months (Q1-Q3: 3-7 months). Viral suppression was significantly associated with later calendar year of antiretroviral therapy initiation, no history of injection drug use, lower baseline viral load, being on an initial regimen consisting of non-nucleoside reverse-transcriptase inhibitors, and older age. Among those who suppressed, 295 (12 %) experienced viral rebound. This was associated with earlier calendar year of antiretroviral therapy initiation, injection drug use history, younger age, higher baseline CD4 cell count, and living in British Columbia. Further strategies are required to optimize combination antiretroviral therapy outcomes in men who have sex with men in Canada, specifically targeting younger MSM and those with a history of injection drug use.

Can a small-changes approach help address the obesity epidemic? A report of the Joint Task Force of the American Society for Nutrition, Institute of Food Technologists, and International Food Information Council.

PubMed

Hill, James O

2009-02-01

The continued rise in obesity rates in most countries suggests that current programs and initiatives designed to combat obesity have not been successful in reversing the obesity epidemic. Obesity rates are increasing because of a gradual weight gain in most populations. There has been little long-term success in treating established obesity through lifestyle change, perhaps because of the large permanent changes in diet and physical activity required to keep weight off. An alternative strategy to address the obesity epidemic involves not focusing on weight loss but promoting small changes in diet and physical activity to initially prevent further weight gain. With the use of this strategy, obesity rates could first be stabilized in most populations and then, over time, decrease gradually. Supporting data show that small reductions in conscious energy intake and increases in physical activity can reduce excessive weight gain. The opportunity exists to use the small-changes approach to bring different stakeholders together to create a national initiative to address the global epidemic of obesity. The Joint Task Force of the American Society for Nutrition, Institute of Food Technologists, and International Food Information Council believe that a small-changes framework, aimed at helping people make conscious small changes in lifestyle behaviors, in combination with efforts by the private sector to gradually "ratchet down" some of the environmental factors that have contributed to excessive energy intake and the declining rates of physical activity, can be successful in reducing obesity rates. Such an initiative would benefit from the support of educational and social marketing campaigns developed with governmental input and support.

Development and validation of a measure of pediatric oral health-related quality of life: the POQL

PubMed Central

Huntington, Noelle L; Spetter, Dante; Jones, Judith A.; Rich, Sharon E.; Garcia, Raul I.; Spiro, Avron

2011-01-01

Objective To develop a brief measure of oral health-related quality of life in children and demonstrate its reliability and validity in a diverse population. Methods We administered the initial 20-item POQL to children (Child Self-Report) and parents (Parent Report on Child) from diverse populations in both school-based and clinic-based settings. Clinical oral health status was measured on a subset of children. We used factor analysis to determine the underlying scales and then reduced the measure to 10 items based on several considerations. Multitrait analysis on the resulting 10-item POQL was used to reaffirm the discrimination of scales and assess the measure’s internal consistency and interscale correlations. We established discriminant and convergent validity with clinical status, perceived oral health and responses on the PedsQL and determined sensitivity to change with children undergoing ECC surgical repair. Results Factor analysis returned a four-scale solution for the initial items – Physical Functioning, Role Functioning, Social Functioning and Emotional Functioning. The reduced items represented the same four scales – two each on Physical and Role and three each on Social and Emotional. Good reliability and validity were shown for the POQL as a whole and for each of the scales. Conclusions The POQL is a valid and reliable measure of oral health-related quality of life for use in pre-school and school-aged children, with high utility for both clinical assessments and large-scale population studies. PMID:21972458

Development and validation of a measure of pediatric oral health-related quality of life: the POQL.

PubMed

Huntington, Noelle L; Spetter, Dante; Jones, Judith A; Rich, Sharron E; Garcia, Raul I; Spiro, Avron

2011-01-01

To develop a brief measure of oral health-related quality of life (OHQL) in children and demonstrate its reliability and validity in a diverse population. We administered the initial 20-item Pediatric Oral Health-Related Quality of Life (POQL) to children (Child Self-Report) and parents (Parent Report on Child) from diverse populations in both school-based and clinic-based settings. Clinical oral health status was measured on a subset of children. We used factor analysis to determine the underlying scales and then reduced the measure to 10 items based on several considerations. Multitrait analysis on the resulting 10-item POQL was used to reaffirm the discrimination of scales and assess the measure's internal consistency and interscale correlations. We established discriminant and convergent validity with clinical status, perceived oral health and responses on the PedsQL, and determined sensitivity to change with children undergoing ECC surgical repair. Factor analysis returned a four-scale solution for the initial items--Physical Functioning, Role Functioning, Social Functioning, and Emotional Functioning. The reduced items represented the same four scales--two each on Physical and Role and three each on Social and Emotional. Good reliability and validity were shown for the POQL as a whole and for each of the scales. The POQL is a valid and reliable measure of OHQL for use in preschool and school-aged children, with high utility for both clinical assessments and large-scale population studies.

Ecological correlates of invasion impact for Burmese pythons in Florida

USGS Publications Warehouse

Reed, R.N.; Willson, J.D.; Rodda, G.H.; Dorcas, M.E.

2012-01-01

An invasive population of Burmese pythons (Python molurus bivittatus) is established across several thousand square kilometers of southern Florida and appears to have caused precipitous population declines among several species of native mammals. Why has this giant snake had such great success as an invasive species when many established reptiles have failed to spread? We scored the Burmese python for each of 15 literature-based attributes relative to predefined comparison groups from a diverse range of taxa and provide a review of the natural history and ecology of Burmese pythons relevant to each attribute. We focused on attributes linked to spread and magnitude of impacts rather than establishment success. Our results suggest that attributes related to body size and generalism appeared to be particularly applicable to the Burmese python's success in Florida. The attributes with the highest scores were: high reproductive potential, low vulnerability to predation, large adult body size, large offspring size and high dietary breadth. However, attributes of ectotherms in general and pythons in particular (including predatory mode, energetic efficiency and social interactions) might have also contributed to invasion success. Although establishment risk assessments are an important initial step in prevention of new establishments, evaluating species in terms of their potential for spreading widely and negatively impacting ecosystems might become part of the means by which resource managers prioritize control efforts in environments with large numbers of introduced species.

Differential recovery of habitat use by birds after wind farm installation: A multi-year comparison

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

Farfán, M.A., E-mail: mafarfanaguilar@hotmail.com; Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Málaga; Duarte, J., E-mail: jddofitecma@gmail.com

Onshore wind farms remain one of the most widely used technologies for the production of renewable energy. These are known to affect birds through disturbance or collision. Most research focus on the impact of wind farms on raptors or other large bird species, especially those of conservation concern. However, limited information exists on the effect of wind farms on small birds. Recovery of large versus small bird populations impacted by wind farms is also largely unstudied. A reason for this is the lack of long-term datasets based on standardized, systematic assessments. We monitored birds in the vicinity of a windmore » farm in an upland habitat in southern Spain (Malaga province), immediately after installation and 6.5 years post-construction. During both study periods, we observed 11 raptor and 38 non-raptor species (including 30 passerines). We found differences in recovery rates between raptors and non-raptors. Raptors showed an upturn in numbers but non-raptor abundance fell significantly. Greater attention should be paid to the recovery of wildlife after initial impact assessments than at present. This study confirms that regulatory authorities and developers should consider the likely impacts of wind farms on small bird populations. Mitigation measures focused particularly on non-raptor species should be considered and implemented as a means to reduce these negative effects.« less

Novel Stimulation Paradigms with Temporally-Varying Parameters to Reduce Synchronous Activity at the Onset of High Frequency Stimulation in Rat Hippocampus

PubMed Central

Cai, Ziyan; Feng, Zhouyan; Guo, Zheshan; Zhou, Wenjie; Wang, Zhaoxiang; Wei, Xuefeng

2017-01-01

Deep brain stimulation (DBS) has shown wide applications for treating various disorders in the central nervous system by using high frequency stimulation (HFS) sequences of electrical pulses. However, upon the onset of HFS sequences, the narrow pulses could induce synchronous firing of action potentials among large populations of neurons and cause a transient phase of “onset response” that is different from the subsequent steady state. To investigate the transient onset phase, the antidromically-evoked population spikes (APS) were used as an electrophysiological marker to evaluate the synchronous neuronal reactions to axonal HFS in the hippocampal CA1 region of anesthetized rats. New stimulation paradigms with time-varying intensity and frequency were developed to suppress the “onset responses”. Results show that HFS paradigms with ramp-up intensity at the onset phase could suppress large APS potentials. In addition, an intensity ramp with a slower ramp-up rate or with a higher pulse frequency had greater suppression on APS amplitudes. Therefore, to reach a desired pulse intensity rapidly, a stimulation paradigm combining elevated frequency and ramp-up intensity was used to shorten the transition phase of initial HFS without evoking large APS potentials. The results of the study provide important clues for certain transient side effects of DBS and for development of new adaptive stimulation paradigms. PMID:29066946

Variation in pollen limitation and floral parasitism across a mating system transition in a Pacific coastal dune plant: evolutionary causes or ecological consequences?

PubMed

Dart, Sara; Eckert, Christopher G

2015-02-01

Evolutionary transitions from outcrossing to self-fertilization are thought to occur because selfing provides reproductive assurance when pollinators or mates are scarce, but they could also occur via selection to reduce floral vulnerability to herbivores. This study investigated geographic covariation between floral morphology, fruit set, pollen limitation and florivory across the geographic range of Camissoniopsis cheiranthifolia, a Pacific coastal dune endemic that varies strikingly in flower size and mating system. Fruit set was quantified in 75 populations, and in 41 of these floral herbivory by larvae of a specialized moth (Mompha sp.) that consumes anthers in developing buds was also quantified. Experimental pollen supplementation was performed to quantify pollen limitation in three large-flowered, outcrossing and two small-flowered, selfing populations. These parameters were also compared between large- and small-flowered phenotypes within three mixed populations. Fruit set was much lower in large-flowered populations, and also much lower among large- than small-flowered plants within populations. Pollen supplementation increased per flower seed production in large-flowered but not small-flowered populations, but fruit set was not pollen limited. Hence inadequate pollination cannot account for the low fruit set of large-flowered plants. Floral herbivory was much more frequent in large-flowered populations and correlated negatively with fruit set. However, florivores did not preferentially attack large-flowered plants in three large-flowered populations or in two of three mixed populations. Selfing alleviated pollen limitation of seeds per fruit, but florivory better explains the marked variation in fruit set. Although florivory was more frequent in large-flowered populations, large-flowered individuals were not generally more vulnerable within populations. Rather than a causative selective factor, reduced florivory in small-flowered, selfing populations is probably an ecological consequence of mating system differentiation, with potentially significant effects on population demography and biotic interactions. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Collaborative Research in Childhood Cancer Survivorship: The Current Landscape

PubMed Central

Bhatia, Smita; Armenian, Saro H.; Armstrong, Gregory T.; van Dulmen-den Broeder, Eline; Hawkins, Michael M.; Kremer, Leontien C.M.; Kuehni, Claudia E.; Olsen, Jørgen H.; Robison, Leslie L.; Hudson, Melissa M.

2015-01-01

Survivors of childhood cancer carry a substantial burden of morbidity and are at increased risk for premature death. Furthermore, clear associations exist between specific therapeutic exposures and the risk for a variety of long-term complications. The entire landscape of health issues encountered for decades after successful completion of treatment is currently being explored in various collaborative research settings. These settings include large population-based or multi-institutional cohorts and single-institution studies. The ascertainment of outcomes has depended on self-reporting, linkage to registries, or clinical assessments. Survivorship research in the cooperative group setting, such as the Children's Oncology Group, has leveraged the clinical trials infrastructure to explore the molecular underpinnings of treatment-related adverse events, and to understand specific complications in the setting of randomized risk-reduction strategies. This review highlights the salient findings from these large collaborative initiatives, emphasizing the need for life-long follow-up of survivors of childhood cancer, and describing the development of several guidelines and efforts toward harmonization. Finally, the review reinforces the need to identify populations at highest risk, facilitating the development of risk prediction models that would allow for targeted interventions across the entire trajectory of survivorship. PMID:26304891

A large cross-sectional study of health attitudes, knowledge, behaviour and risks in the post-war Croatian population (the First Croatian Health Project).

PubMed

Turek, S; Rudan, I; Smolej-Narancić, N; Szirovicza, L; Cubrilo-Turek, M; Zerjavić-Hrabak, V; Rak-Kaić, A; Vrhovski-Hebrang, D; Prebeg, Z; Ljubicić, M; Janićijević, B; Rudan, P

2001-06-01

As the liberation of occupied Croatian territories ended the war in the country in 1995, the Ministry of Health and Croatian Health Insurance Institute have agreed to create the new framework for developing a long-term strategy of public health planning, prevention and intervention. They provided financial resources to develop the First Croatian Health Project, the rest of the support coming from the World Bank loan and the National Institute of Public Health. A large cross-sectional study was designed aiming to assess health attitudes, knowledge, behaviour and risks in the post-war Croatian population. The large field study was carried out by the Institute for Anthropological Research with technical support from the National Institute of Public Health. The field study was completed between 1995-1997. It included about 10,000 adult volunteers from all 21 Croatian counties. The geographic distribution of the sample covered both coastal and continental areas of Croatia and included rural and urban environments. The specific measurements included antropometry (body mass index and blood pressure). From each examinee a blood sample was collected from which the levels of total plasma cholesterol (TC), triglycerides (TG), HDL-cholesterol (High Density Lipoprotein), LDL-cholesterol (Low Density Lipoprotein), lipoprotein Lp(a), and haemostatic risk factor fibrinogen (F) were determined. The detailed data were collected on the general knowledge and attitudes on health issues, followed by specific investigation of smoking history, alcohol consumption, nutrition habits, physical activity, family history of chronic non-communicable diseases and occupational exposures. From the initial database a targeted sample of 5,840 persons of both sexes, aged 18-65, was created corresponding by age, sex and geographic distribution to the general Croatian population. This paper summarises and discusses the main findings of the project within this representative sample of Croatian population.

A comparison of genetic ariation between an anadromous steelhead, Oncorhynchus mykiss, population and seven derived populations sequestered in freshwater for 70 years

USGS Publications Warehouse

Thrower, Frank; Guthrie, Charles; Nielsen, Jennifer L.; Joyce, John

2004-01-01

In 1926 cannery workers from the Wakefield Fisheries Plant at Little Port Walter in Southeast Alaska captured small trout, Oncorhynchus mykiss, from a portion of Sashin Creek populated with a wild steelhead (anadromous O. mykiss) run. They planted them into Sashin Lake which had been fishless to that time and separated from the lower stream by two large waterfalls that prevented upstream migration of any fish. In 1996 we sampled adult steelhead from the lower creek and juvenile O. mykiss from an intermediate portion of the creek, Sashin Lake, and five lakes that had been stocked with fish from Sashin Lake in 1938. Tissue samples from these eight populations were compared for variation in: microsatellite DNA at 10 loci; D-loop sequences in mitochondrial DNA; and allozymes at 73 loci known to be variable in steelhead. Genetic variability was consistently less in the Sashin Lake population and all derived populations than in the source anadromous population. The cause of this reduction is unknown but it is likely that very few fish survived to reproduce from the initial transplant in 1926. Stockings of 50–85 fish into five other fishless lakes in 1938 from Sashin Lake did not result in a similar dramatic reduction in variability. We discuss potential explanations for the observed patterns of genetic diversity in relation to the maintenance of endangered anadromous O. mykiss populations in freshwater refugia.

Parents’ Support and Knowledge of Their Daughters’ Lives and Females’ Early Sexual Initiation in Nine European Countries

PubMed Central

Madkour, Aubrey Spriggs; Farhat, Tilda; Halpern, Carolyn Tucker; Nic Gabhainn, Saoirse; Godeau, Emmanuelle

2013-01-01

Context The association between early sexual initiation and parenting practices (e.g., support and knowledge) has not been tested in multiple European population-based samples using the same instrument. Methods Data provided by females (age 14-16) participating in the 2005-06 Health Behaviors in School-Aged Children (HBSC) survey conducted in Austria, Finland, Greece, Hungary, Iceland, Lithuania, Romania, Spain and Ukraine were used (n=7,466). The dependent variable was early sexual initiation (<16). The main independent variables were maternal and paternal support and knowledge of daily activities. Univariate, bivariate and multivariable analyses were run with standard error corrections and weights. Results Prevalence of early sexual initiation ranged from a low of 7% (Romania) to a high of 35% (Iceland). In bivariate analyses, maternal and paternal support were significantly negatively related to adolescent females’ early sexual initiation in a majority of countries. In models with demographic controls, parental support was significantly negatively related to early sexual initiation (AOR = 0.80 maternal, 0.74 paternal). After adding parental knowledge, early sexual initiation was no longer associated with parental support, but was significantly negatively related to parental knowledge (AOR = 0.69 maternal and paternal). These patterns held across countries. Conclusions Negative associations between parental support and early initiation were largely explained by parental knowledge, suggesting either that knowledge is more important than support or that knowledge mediates the association between support and early initiation. Providers should counsel parents regarding the importance of knowledge of their daughters’ daily lives, which may be enhanced through developing supportive relationships. PMID:22958661

Contributions of long-distance dispersal to population growth in colonising Pinus ponderosa populations.

PubMed

Lesser, Mark R; Jackson, Stephen T

2013-03-01

Long-distance dispersal is an integral part of plant species migration and population development. We aged and genotyped 1125 individuals in four disjunct populations of Pinus ponderosa that were initially established by long-distance dispersal in the 16th and 17th centuries. Parentage analysis was used to determine if individuals were the product of local reproductive events (two parents present), long-distance pollen dispersal (one parent present) or long-distance seed dispersal (no parents present). All individuals established in the first century at each site were the result of long-distance dispersal. Individuals reproduced at younger ages with increasing age of the overall population. These results suggest Allee effects, where populations were initially unable to expand on their own, and were dependent on long-distance dispersal to overcome a minimum-size threshold. Our results demonstrate that long-distance dispersal was not only necessary for initial colonisation but also to sustain subsequent population growth during early phases of expansion. © 2012 Blackwell Publishing Ltd/CNRS.

Truncation of the Binary Distribution Function in Globular Cluster Formation

NASA Astrophysics Data System (ADS)

Vesperini, E.; Chernoff, David F.

1996-02-01

We investigate a population of primordial binaries during the initial stage of evolution of a star cluster. For our calculations we assume that equal-mass stars form rapidly in a tidally truncated gas cloud, that ˜10% of the stars are in binaries, and that the resulting star cluster undergoes an epoch of violent relaxation. We study the collisional interaction of the binaries and single stars, in particular, the ionization of the binaries and the energy exchange between binaries and single stars. We find that for large N systems (N > 1000), even the most violent beginning leaves the binary distribution function largely intact. Hence, the binding energy originally tied up in the cloud's protostellar pairs is preserved during the relaxation process, and the binaries are available to interact at later times within the virialized cluster.

Age-associated Pro-inflammatory Remodeling and Functional Phenotype in the Heart and Large Arteries

PubMed Central

Wang, Mingyi; Shah, Ajay M

2015-01-01

The aging population is increasing dramatically. Aging–associated stress simultaneously drives proinflammatory remodeling, involving angiotensin II and other factors, in both the heart and large arteries. The structural remodeling and functional changes that occur with aging include cardiac and vascular wall stiffening, systolic hypertension and suboptimal ventricular-arterial coupling, features that are often clinically silent and thus termed a silent syndrome. These age-related effects are the result of responses initiated by cardiovascular proinflammatory cells. Local proinflammatory signals are coupled between the heart and arteries due to common mechanical and humoral messengers within a closed circulating system. Thus, targeting proinflammatory signaling molecules would be a promising approach to improve age-associated suboptimal ventricular-arterial coupling, a major predisposing factor for the pathogenesis of clinical cardiovascular events such as heart failure. PMID:25665458

MLS student active learning within a "cloud" technology program.

PubMed

Tille, Patricia M; Hall, Heather

2011-01-01

In November 2009, the MLS program in a large public university serving a geographically large, sparsely populated state instituted an initiative for the integration of technology enhanced teaching and learning within the curriculum. This paper is intended to provide an introduction to the system requirements and sample instructional exercises used to create an active learning technology-based classroom. Discussion includes the following: 1.) define active learning and the essential components, 2.) summarize teaching methods, technology and exercises utilized within a "cloud" technology program, 3.) describe a "cloud" enhanced classroom and programming 4.) identify active learning tools and exercises that can be implemented into laboratory science programs, and 5.) describe the evaluation and assessment of curriculum changes and student outcomes. The integration of technology in the MLS program is a continual process and is intended to provide student-driven active learning experiences.

Evaluation of the status of anurans on a refuge in suburban Maryland

USGS Publications Warehouse

Brander, S.M.; Royle, J. Andrew; Eames, M.

2007-01-01

Because many anurans have well-defined breeding seasons and male anurans produce loud advertisement calls, surveys of these breeding choruses are believed to provide a dependable means of monitoring population trends. The Patuxent Research Refuge initiated such a calling survey in the spring of 1997, which uses volunteers to collect anuran (frog and toad) calling survey data. The primary goal of initiating the calling surveys at the Patuxent Refuge was to obtain baseline information on anuran populations, such as species occurrence, frequency of occurrence, and relative abundance over time. In this paper, we used the calling survey data to develop models for the ?proportion of area occupied? by individual anuran species, a method in which analysis is focused on the proportion of sites that are occupied by a species, instead of the number of individuals present in the population. This type of analysis is ideal for use in large-scale monitoring programs focused on species that are difficult to count, such as anurans or birds. We considered models for proportion of area occupied that allow for imperfect detection (that is, a species may be present but go undetected during sampling) by incorporating parameters that describe detection probability and the response of detection probability to various environmental and sampling covariates. Our results indicate that anuran populations on the Patuxent Research Refuge have high rates of occupancy compared to areas nearby and that extinction and colonization rates are stable. The potential uses for ?proportion of area occupied? analyses are far-reaching and will allow for more accurate quantification of data and better-informed management decisions for calling surveys on a larger scale.

Evaluation of the status of anurans on a refuge in suburban Maryland

USGS Publications Warehouse

Brander, S.M.; Royle, J. Andrew; Eames, M.

2007-01-01

Because many anurans have well-defined breeding seasons and male anurans produce loud advertisement calls, surveys of these breeding choruses are believed to provide a dependable means of monitoring population trends. The Patuxent Research Refuge initiated such a calling survey in the spring of 1997, which uses volunteers to collect anuran (frog and toad) calling survey data. The primary goal of initiating the calling surveys at the Patuxent Refuge was to obtain baseline information on anuran populations, such as species occurrence, frequency of occurrence, and relative abundance over time. In this paper, we used the calling survey data to develop models for the "proportion of area occupied" by individual anuran species, a method in which analysis is focused on the proportion of sites that are occupied by a species, instead of the number of individuals present in the population. This type of analysis is ideal for use in large-scale monitoring programs focused on species that are difficult to count, such as anurans or birds. We considered models for proportion of area occupied that allow for imperfect detection (that is, a species may be present but go undetected during sampling) by incorporating parameters that describe detection probability and the response of detection probability to various environmental and sampling covariates. Our results indicate that anuran populations on the Patuxent Research Refuge have high rates of occupancy compared to areas nearby and that extinction and colonization rates are stable. The potential uses for "proportion of area occupied" analyses are far-reaching and will allow for more accurate quantification of data and better-informed management decisions for calling surveys on a larger scale. Copyright 2007 Society for the Study of Amphibians and Reptiles.

KINETyS II: Constraints on spatial variations of the stellar initial mass function from K-band spectroscopy

NASA Astrophysics Data System (ADS)

Alton, P. D.; Smith, R. J.; Lucey, J. R.

2018-05-01

We investigate the spatially resolved stellar populations of a sample of seven nearby massive Early-type galaxies (ETGs), using optical and near infrared data, including K-band spectroscopy. This data offers good prospects for mitigating the uncertainties inherent in stellar population modelling by making a wide variety of strong spectroscopic features available. We report new VLT-KMOS measurements of the average empirical radial gradients out to the effective radius in the strengths of the Ca I 1.98 μm and 2.26 μm features, the Na I 2.21 μm line, and the CO 2.30 μm bandhead. Following previous work, which has indicated an excess of dwarf stars in the cores of massive ETGs, we pay specific attention to radial variations in the stellar initial mass function (IMF) as well as modelling the chemical abundance patterns and stellar population ages in our sample. Using state-of-the-art stellar population models we infer an [Fe/H] gradient of -0.16±0.05 per dex in fractional radius and an average [Na/Fe] gradient of -0.35±0.09. We find a large but radially-constant enhancement to [Mg/Fe] of ˜ 0.4 and a much lower [Ca/Fe] enhancement of ˜ 0.1. Finally, we find no significant IMF radial gradient in our sample on average and find that most galaxies in our sample are consistent with having a Milky Way-like IMF, or at most a modestly bottom heavy IMF (e.g. less dwarf enriched than a single power law IMF with the Salpeter slope).

Analysis of the Afrikaner mutation in exon 9 of the low-density lipoprotein receptor gene in a large Dutch kindred suffering from familial hypercholesterolaemia.

PubMed

Defesche, J C; Lansberg, P J; Reymer, P W; Lamping, R J; Kastelein, J J

1993-02-01

Familial hypercholesterolaemia (FH) is the most common genetic metabolic disorder, affecting about 1 in 500 persons in the general population. With novel techniques, it is possible to identify the molecular defects underlying FH in the gene coding for the low-density lipoprotein (LDL) receptor, thereby confirming the diagnosis of FH. In this study we present a large family with a specific mutation in exon 9 of the LDL-receptor gene (an Afrikaner mutation) and we demonstrate that by a large-scale case-finding study in this family, carriers of such a mutation can be detected. Of 63 family members, 13 were shown to be at risk for cardiovascular disease as judged by their lipoprotein profile or the presence of the Afrikaner mutation. Two persons were detected, affected with a dyslipidaemia other than FH. Medical management was initiated in order to reduce the high cardiovascular risk associated with this disorder.

The importance of initial protection of conspicuous mutants for the coevolution of defense and aposematic signaling of the defense: a modeling study.

PubMed

Ruxton, Graeme D; Speed, Michael P; Broom, Mark

2007-09-01

Most models of the evolution of aposematic signaling assume (1) that the secondary defense being signaled is fixed, and (2) that conspicuous mutants arising in a population of defended individuals of cryptic appearance are initially protected from predation. Previous models of ours relaxed the first assumption, here we relax the second and compare with our earlier work to explore the consequences of initial protection from predation on the coevolution of secondary defense and aposematic signaling. As expected, we find that aposematic signaling evolves more easily if initial protection is available. Less obviously, the coevolved level of secondary defense should also be higher if initial protection is provided. Across species or populations, we predict that when initial protection occurs, then strength of aposematic signal should be correlated with the strength of the underlying secondary defense, whereas no such correlation should occur without initial protection. Finally, we demonstrate that species can invest heavily in a secondary defense and remain maximally cryptic (forgoing the advantages of aposematic signaling) and that within a species we should expect strong variation in appearance between populations but much less variation within populations. Hence, we demonstrate that whether conspicuous morphs receive initial protection from predation has powerful and potentially empirically detectible consequences for the coevolution of secondary defenses and aposematic signaling.

Genetic differentiation between upland and lowland populations shapes the Y-chromosomal landscape of West Asia.

PubMed

Balanovsky, O; Chukhryaeva, M; Zaporozhchenko, V; Urasin, V; Zhabagin, M; Hovhannisyan, A; Agdzhoyan, A; Dibirova, K; Kuznetsova, M; Koshel, S; Pocheshkhova, E; Alborova, I; Skhalyakho, R; Utevska, O; Mustafin, Kh; Yepiskoposyan, L; Tyler-Smith, C; Balanovska, E

2017-04-01

Y-chromosomal variation in West Asian populations has so far been studied in less detail than in the neighboring Europe. Here, we analyzed 598 Y-chromosomes from two West Asian subregions-Transcaucasia and the Armenian plateau-using 40 Y-SNPs and 17 Y-STRs and combined them with previously published data from the region. The West Asian populations fell into two clusters: upland populations from the Anatolian, Armenian and Iranian plateaus, and lowland populations from the Levant, Mesopotamia and the Arabian Peninsula. This geographic subdivision corresponds with the linguistic difference between Indo-European and Turkic speakers, on the one hand, and Semitic speakers, on the other. This subdivision could be traced back to the Neolithic epoch, when upland populations from the Anatolian and Iranian plateaus carried similar haplogroup spectra but did not overlap with lowland populations from the Levant. We also found that the initial gene pool of the Armenian motherland population has been well preserved in most groups of the Armenian Diaspora. In view of the contribution of West Asians to the autosomal gene pool of the steppe Yamnaya archaeological culture, we sequenced a large portion of the Y-chromosome in haplogroup R1b samples from present-day East European steppe populations. The ancient Yamnaya samples are located on the "eastern" R-GG400 branch of haplogroup R1b-L23, showing that the paternal descendants of the Yamnaya still live in the Pontic steppe and that the ancient Yamnaya population was not an important source of paternal lineages in present-day West Europeans.

Large-Scale 1:1 Computing Initiatives: An Open Access Database

ERIC Educational Resources Information Center

Richardson, Jayson W.; McLeod, Scott; Flora, Kevin; Sauers, Nick J.; Kannan, Sathiamoorthy; Sincar, Mehmet

2013-01-01

This article details the spread and scope of large-scale 1:1 computing initiatives around the world. What follows is a review of the existing literature around 1:1 programs followed by a description of the large-scale 1:1 database. Main findings include: 1) the XO and the Classmate PC dominate large-scale 1:1 initiatives; 2) if professional…

Insulin oedema in a child with newly diagnosed diabetes mellitus.

PubMed

Aravamudhan, Avinash; Gardner, Chris; Smith, Claire; Senniappan, Senthil

2014-05-01

Insulin oedema is a rare complication of insulin therapy for diabetes mellitus. It has been reported in type 1 diabetes mellitus, in poorly controlled type 2 diabetes mellitus following either the initiation or intensification of insulin therapy and in underweight patients on large doses of insulin. There are only a few case reports since it was first described in 1928, showing that it is an uncommon and probably an under-reported complication. The majority of those reports have been in the adult population. The generalised oedema tends to develop shortly after initiation or intensification of insulin therapy and resolves spontaneously within few weeks. We present one of the youngest patients reported in the literature, a 9-year-old boy who developed insulin oedema within few days of presenting with diabetic ketoacidosis. The case highlights the importance of recognising this generally transient and self-resolving complication and differentiating it from other serious causes of oedema.

Neuroglian-positive plasmatocytes of Manduca sexta and the initiation of hemocyte attachment to foreign surfaces.

PubMed

Nardi, James B; Pilas, Barbara; Bee, Charles Mark; Zhuang, Shufei; Garsha, Karl; Kanost, Michael R

2006-01-01

Observations of hemocyte aggregation on abiotic surfaces suggested that certain plasmatocytes from larvae of Manduca sexta act as foci for hemocyte aggregation. To establish how these particular plasmatocytes form initial attachments to foreign surfaces, they were cultured separately from other selected populations of hemocytes. While all circulating plasmatocytes immunolabel with anti-beta-integrin monoclonal antibody (MAb), only these larger plasmatocytes immunolabel with a MAb to the adhesion protein neuroglian. Neuroglian-negative plasmatocytes and granular cells that have been magnetically segregated from the majority of granular cells adhere to each other but fail to adhere to foreign substrata; by contrast, neuroglian-positive plasmatocytes that segregate with most granular cells adhere firmly to a substratum. Hemocytes form stable aggregates around the large, neuroglian-positive plasmatocytes. However, if neuroglian-positive plasmatocytes are separated from most granular cells, attachment of these plasmatocytes to foreign surfaces is suppressed.

Rewards and the evolution of cooperation in public good games.

PubMed

Sasaki, Tatsuya; Uchida, Satoshi

2014-01-01

Properly coordinating cooperation is relevant for resolving public good problems, such as clean energy and environmental protection. However, little is known about how individuals can coordinate themselves for a certain level of cooperation in large populations of strangers. In a typical situation, a consensus-building process rarely succeeds, owing to a lack of face and standing. The evolution of cooperation in this type of situation is studied here using threshold public good games, in which cooperation prevails when it is initially sufficient, or otherwise it perishes. While punishment is a powerful tool for shaping human behaviours, institutional punishment is often too costly to start with only a few contributors, which is another coordination problem. Here, we show that whatever the initial conditions, reward funds based on voluntary contribution can evolve. The voluntary reward paves the way for effectively overcoming the coordination problem and efficiently transforms freeloaders into cooperators with a perceived small risk of collective failure.

Adolescent human papillomavirus vaccination in the United States: Opportunities for integrating pharmacies into the immunization neighborhood.

PubMed

Fava, Joseph P; Colleran, Jacob; Bignasci, Francesca; Cha, Raymond; Kilgore, Paul E

2017-08-03

Human Papillomavirus (HPV) vaccination faces several barriers, including a social stigma which carries religious and philosophical implications among parents of adolescents as well as young adults. Hundreds of immunization interventions and programs have been developed to address these factors and boost HPV vaccination rates in the United States. We sought to review the existing literature highlighting barriers to HPV immunization, as well as programs targeting increased HPV vaccine uptake in effort to develop novel vaccination initiatives. The most impactful barriers identified were parental stigma and low quality of provider recommendations for the vaccine. Despite the implementation of many HPV initiatives, outcomes of these programs are largely limited to modest improvements in vaccine uptake in small, homogeneous populations. We describe pharmacies as distinctly advantageous but underutilized resources within the immunization neighborhood and propose a novel concept to improve vaccination rates as well as reduce HPV-related disease burden in all demographics.

Climate change alters diffusion of forest pest: A model study

NASA Astrophysics Data System (ADS)

Jo, Woo Seong; Kim, Hwang-Yong; Kim, Beom Jun

2017-01-01

Population dynamics with spatial information is applied to understand the spread of pests. We introduce a model describing how pests spread in discrete space. The number of pest descendants at each site is controlled by local information such as temperature, precipitation, and the density of pine trees. Our simulation leads to a pest spreading pattern comparable to the real data for pine needle gall midge in the past. We also simulate the model in two different climate conditions based on two different representative concentration pathways scenarios for the future. We observe that after an initial stage of a slow spread of pests, a sudden change in the spreading speed occurs, which is soon followed by a large-scale outbreak. We found that a future climate change causes the outbreak point to occur earlier and that the detailed spatio-temporal pattern of the spread depends on the source position from which the initial pest infection starts.

Long-Term Obliquity Variations of a Moonless Earth

NASA Astrophysics Data System (ADS)

Barnes, Jason W.; Lissauer, J. J.; Chambers, J. E.

2012-05-01

Earth's present-day obliquity varies by +/-1.2 degrees over 100,000-year timescales. Without the Moon's gravity increasing the rotation axis precession rate, prior theory predicted that a moonless Earth's obliquity would be allowed to vary between 0 and 85 degrees -- moreso even than present-day Mars (0 - 60 degrees). We use a modified version of the symplectic orbital integrator `mercury' to numerically investigate the obliquity evolution of hypothetical moonless Earths. Contrary to the large theoretically allowed range, we find that moonless Earths more typically experience obliquity variations of just +/- 10 degrees over Gyr timescales. Some initial conditions for the moonless Earth's rotation rate and obliquity yield slightly greater variations, but the majority have smaller variations. In particular, retrograde rotators are quite stable and should constitute 50% of the population if initial terrestrial planet rotation is isotropic. Our results have important implications for the prospects of long-term habitability of moonless planets in extrasolar systems.

The Lifetime Surveillance of Astronaut Health (LSAH) Project

NASA Technical Reports Server (NTRS)

Bopp, Eugenia; Wear, Mary L.; Lee, Lesley R.; VanBaalen, Mary

2013-01-01

From 1989-2010 NASA conducted a research study, the Longitudinal Study of Astronaut Health, to investigate the incidence of acute and chronic morbidity and mortality in astronauts and to determine whether their occupational exposures were associated with increased risk of death or disability. In 2004, the Institute of Medicine recommended that NASA convert the longitudinal study into an occupational health surveillance program and in 2010, NASA initiated the Lifetime Surveillance of Astronaut Health project. The new program collects data on astronaut workplace exposures, especially those occurring in the training and space flight environments, and conducts operational and health care analyses to look for trends in exposure and health outcomes. Astronaut selection and retention medical standards are rigorous, requiring an extensive clinical testing regimen. As a result, this employee population has contributed to a large set of health data available for analyses. Astronauts represent a special population with occupational exposures not typically experienced by other employee populations. Additionally, astronauts are different from the general population in terms of demographic and physiologic characteristics. The challenges and benefits of conducting health surveillance for an employee population with unique occupational exposures will be discussed. Several occupational surveillance projects currently underway to examine associations between astronaut workplace exposures and medical outcomes will be described.

Type 2 Diabetes Susceptibility in the Greek-Cypriot Population: Replication of Associations with TCF7L2, FTO, HHEX, SLC30A8 and IGF2BP2 Polymorphisms

PubMed Central

Votsi, Christina; Toufexis, Costas; Michailidou, Kyriaki; Antoniades, Athos; Skordis, Nicos; Karaolis, Minas; Pattichis, Constantinos S.; Christodoulou, Kyproula

2017-01-01

Type 2 diabetes (T2D) has been the subject of numerous genetic studies in recent years which revealed associations of the disease with a large number of susceptibility loci. We hereby initiate the evaluation of T2D susceptibility loci in the Greek-Cypriot population by performing a replication case-control study. One thousand and eighteen individuals (528 T2D patients, 490 controls) were genotyped at 21 T2D susceptibility loci, using the allelic discrimination method. Statistically significant associations of T2D with five of the tested single nucleotide polymorphisms (SNPs) (TCF7L2 rs7901695, FTO rs8050136, HHEX rs5015480, SLC30A8 rs13266634 and IGF2BP2 rs4402960) were observed in this study population. Furthermore, 14 of the tested SNPs had odds ratios (ORs) in the same direction as the previously published studies, suggesting that these variants can potentially be used in the Greek-Cypriot population for predictive testing of T2D. In conclusion, our findings expand the genetic assessment of T2D susceptibility loci and reconfirm five of the worldwide established loci in a distinct, relatively small, newly investigated population. PMID:28067832

A diffusion model for the fate of tandem gene duplicates in diploids.

PubMed

O'Hely, Martin

2007-06-01

Suppose one chromosome in one member of a population somehow acquires a duplicate copy of the gene, fully linked to the original gene's locus. Preservation is the event that eventually every chromosome in the population is a descendant of the one which initially carried the duplicate. For a haploid population in which the absence of all copies of the gene is lethal, the probability of preservation has recently been estimated via a diffusion approximation. That approximation is shown to carry over to the case of diploids and arbitrary strong selection against the absence of the gene. The techniques used lead to some new results. In the large population limit, it is shown that the relative probability that descendants of a small number of individuals carrying multiple copies of the gene fix in the population is proportional to the number of copies carried. The probability of preservation is approximated when chromosomes carrying two copies of the gene are subject to additional, fully non-functionalizing mutations, thereby modelling either an additional cost of replicating a longer genome, or a partial duplication of the gene. In the latter case the preservation probability depends only on the mutation rate to null for the duplicated portion of the gene.

Exclusion of Patients with a Severe T-Cell Defect Improves the Definition of Common Variable Immunodeficiency.

PubMed

Bertinchamp, Rémi; Gérard, Laurence; Boutboul, David; Malphettes, Marion; Fieschi, Claire; Oksenhendler, Eric

In 2014, the European Society for Immune Deficiencies (ESID) revised the common variable immunodeficiency (CVID) diagnosis criteria by incorporating new clinical and biological markers. The new definition appeared more restrictive but had not yet been evaluated in a large cohort of patients. The objective of this study was to evaluate the impact of this new definition in a large cohort of patients with primary hypogammaglobulinemia. Evaluation of 3 different CVID definitions (ESID/Pan-American Group for Immunodeficiency [PAGID] 1999, ESID 2014, DEFI 2015) in 521 patients included in the French DEFI study with a diagnosis of primary hypogammaglobulinemia. Using the ESID/PAGID 1999 definition, 351 patients were classified as CVID. The new ESID 2014 definition excluded 62 (18%) patients. Most of them (n = 56; 90%) had a less severe disease, whereas 6 (10%) presented with a severe disease with major T-cell defect. We propose different criteria (occurrence of opportunistic infection or very low naive CD4+ T-cell count) to define this population with severe T-cell defect. Sixty-two patients fulfilled these criteria, represented 20% of the initial CVID population but accounted for 77% of the deaths, with a 5-year overall survival of 67.6% (95% confidence interval, 51.0-79.6), and were considered as late onset combined immunodeficiency (LOCID). The new ESID definition for CVID still fails to exclude a large number of patients with severe T-cell defect. We propose a new definition (DEFI 2015) that excluded more patients with a T-cell defect and consider these patients as LOCID. This population has a poor outcome and should be considered as a distinct group requiring specific care. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Stirred suspension bioreactors as a novel method to enrich germ cells from pre-pubertal pig testis.

PubMed

Dores, C; Rancourt, D; Dobrinski, I

2015-05-01

To study spermatogonial stem cells the heterogeneous testicular cell population first needs to be enriched for undifferentiated spermatogonia, which contain the stem cell population. When working with non-rodent models, this step requires working with large numbers of cells. Available cell separation methods rely on differential properties of testicular cell types such as expression of specific cell surface proteins, size, density, or differential adhesion to substrates to separate germ cells from somatic cells. The objective of this study was to develop an approach that allowed germ cell enrichment while providing efficiency of handling large cell numbers. Here, we report the use of stirred suspension bioreactors (SSB) to exploit the adhesion properties of Sertoli cells to enrich cells obtained from pre-pubertal porcine testes for undifferentiated spermatogonia. We also compared the bioreactor approach with an established differential plating method and the combination of both: SSB followed by differential plating. After 66 h of culture, germ cell enrichment in SSBs provided 7.3 ± 1.0-fold (n = 9), differential plating 9.8 ± 2.4-fold (n = 6) and combination of both methods resulted in 9.1 ± 0.3-fold enrichment of germ cells from the initial germ cell population (n = 3). To document functionality of cells recovered from the bioreactor, we demonstrated that cells retained their functional ability to reassemble seminiferous tubules de novo after grafting to mouse hosts and to support spermatogenesis. These results demonstrate that the SSB allows enrichment of germ cells in a controlled and scalable environment providing an efficient method when handling large cell numbers while reducing variability owing to handling. © 2015 American Society of Andrology and European Academy of Andrology.

Coalescence of repelling colloidal droplets: a route to monodisperse populations.

PubMed

Roger, Kevin; Botet, Robert; Cabane, Bernard

2013-05-14

Populations of droplets or particles dispersed in a liquid may evolve through Brownian collisions, aggregation, and coalescence. We have found a set of conditions under which these populations evolve spontaneously toward a narrow size distribution. The experimental system consists of poly(methyl methacrylate) (PMMA) nanodroplets dispersed in a solvent (acetone) + nonsolvent (water) mixture. These droplets carry electrical charges, located on the ionic end groups of the macromolecules. We used time-resolved small angle X-ray scattering to determine their size distribution. We find that the droplets grow through coalescence events: the average radius (R) increases logarithmically with elapsed time while the relative width σR/(R) of the distribution decreases as the inverse square root of (R). We interpret this evolution as resulting from coalescence events that are hindered by ionic repulsions between droplets. We generalize this evolution through a simulation of the Smoluchowski kinetic equation, with a kernel that takes into account the interactions between droplets. In the case of vanishing or attractive interactions, all droplet encounters lead to coalescence. The corresponding kernel leads to the well-known "self-preserving" particle distribution of the coalescence process, where σR/(R) increases to a plateau value. However, for droplets that interact through long-range ionic repulsions, "large + small" droplet encounters are more successful at coalescence than "large + large" encounters. We show that the corresponding kernel leads to a particular scaling of the droplet-size distribution-known as the "second-scaling law" in the theory of critical phenomena, where σR/(R) decreases as 1/√(R) and becomes independent of the initial distribution. We argue that this scaling explains the narrow size distributions of colloidal dispersions that have been synthesized through aggregation processes.

Stirred suspension bioreactors as a novel method to enrich germ cells from pre-pubertal pig testis

PubMed Central

Dores, Camila; Rancourt, Derrick; Dobrinski, Ina

2015-01-01

To study spermatogonial stem cells the heterogeneous testicular cell population first needs to be enriched for undifferentiated spermatogonia, which contain the stem cell population. When working with non-rodent models, this step requires working with large numbers of cells. Available cell separation methods rely on differential properties of testicular cell types such as expression of specific cell surface proteins, size, density or differential adhesion to substrates to separate germ cells from somatic cells. The objective of this study was to develop an approach that allowed germ cell enrichment while providing efficiency of handling large cell numbers. Here we report the use of stirred suspension bioreactors to exploit the adhesion properties of Sertoli cells to enrich cells obtained from pre-pubertal porcine testes for undifferentiated spermatogonia. We also compared the bioreactor approach with an established differential plating method and the combination of both: stirred suspension bioreactor followed by differential plating. After 66 hours of culture, germ cell enrichment in stirred suspension bioreactors provided 7.3±1.0 fold (n=9), differential plating 9.8±2.4 fold (n=6) and combination of both methods resulted in 9.1±0.3 fold enrichment of germ cells from the initial germ cell population (n=3). To document functionality of cells recovered from the bioreactor, we demonstrated that cells retained their functional ability to reassemble seminiferous tubules de novo after grafting to mouse hosts and to support spermatogenesis. These results demonstrate that the stirred suspension bioreactor allows enrichment of germ cells in a controlled and scalable environment providing an efficient method when handling large cell numbers while reducing variability due to handling. PMID:25877677

Using stochastic epidemiological models to evaluate conservation strategies for endangered amphibians

PubMed Central

Griesemer, Marc; Petzold, Linda R.; Briggs, Cheryl J.

2017-01-01

Recent outbreaks of chytridiomycosis, the disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), have contributed to population declines of numerous amphibian species worldwide. The devastating impacts of this disease have led researchers to attempt drastic conservation measures to prevent further extinctions and loss of biodiversity. The conservation measures can be labour-intensive or expensive, and in many cases have been unsuccessful. We developed a mathematical model of Bd outbreaks that includes the effects of demographic stochasticity and within-host fungal load dynamics. We investigated the impacts of one-time treatment conservation strategies during the disease outbreak that occurs following the initial arrival of Bd into a previously uninfected frog population. We found that for all versions of the model, for a large fraction of parameter space, none of the one-time treatment strategies are effective at preventing disease-induced extinction of the amphibian population. Of the strategies considered, treating frogs with antifungal agents to reduce their fungal load had the greatest likelihood of a beneficial outcome and the lowest risk of decreasing the persistence of the frog population, suggesting that this disease mitigation strategy should be prioritized over disinfecting the environment or reducing host density. PMID:28855388

The Effects of Mortality on Fertility: Population Dynamics After a Natural Disaster

PubMed Central

Nobles, Jenna; Frankenberg, Elizabeth; Thomas, Duncan

2015-01-01

Understanding how mortality and fertility are linked is essential to the study of population dynamics. We investigate the fertility response to an unanticipated mortality shock that resulted from the 2004 Indian Ocean tsunami, which killed large shares of the residents of some Indonesian communities but caused no deaths in neighboring communities. Using population-representative multilevel longitudinal data, we identify a behavioral fertility response to mortality exposure, both at the level of a couple and in the broader community. We observe a sustained fertility increase at the aggregate level following the tsunami, which was driven by two behavioral responses to mortality exposure. First, mothers who lost one or more children in the disaster were significantly more likely to bear additional children after the tsunami. This response explains about 13 % of the aggregate increase in fertility. Second, women without children before the tsunami initiated family-building earlier in communities where tsunami-related mortality rates were higher, indicating that the fertility of these women is an important route to rebuilding the population in the aftermath of a mortality shock. Such community-level effects have received little attention in demographic scholarship. PMID:25585644

Trajectories of Ethnoracial Diversity in American Communities, 1980–2010*

PubMed Central

Hall, Matthew; Tach, Laura; Lee, Barrett A.

2017-01-01

The ethnoracial makeup of the U.S. population has undergone transformative change during recent decades, with the non-Hispanic white share of the population shrinking while the minority shares expand. Yet this trend toward greater racial diversity is not universal throughout the nation. Here we propose a framework of segmented change, which incorporates both spatial assimilation and ethnic stratification theories, to better understand variation in patterns of diversification across American communities. Our research applies growth mixture models to decennial census data on places for the 1980–2010 period, finding that trajectories of ethnoracial diversity are much more uneven than popularly claimed. Moreover, types of diversity change are stratified by initial racial composition. While places with mostly-white populations in 1980 underwent extensive diversification, places with larger shares of Hispanics and (especially) blacks in 1980 exhibited less uniform movement toward diversity and were more likely to remain racially homogeneous. Analysis of the underlying group-specific pathways of change indicates that the diversification of white communities was driven largely by Hispanic growth; when areas with a black presence did diversify, it occurred via contracting white populations. These racially conditioned and locally variable patterns emphasize the segmented nature of diversity change in American society. PMID:29398737

Increased level of linkage disequilibrium in rural compared with urban communities: a factor to consider in association-study design.

PubMed

Vitart, Veronique; Carothers, Andrew D; Hayward, Caroline; Teague, Peter; Hastie, Nicholas D; Campbell, Harry; Wright, Alan F

2005-05-01

Few studies have investigated genetic differentiation within nonisolate European populations, despite the initiation of large national sample collections such as U.K. Biobank. Here, we used short tandem repeat markers to explore fine-scale genetic structure and to examine the extent of linkage disequilibrium (LD) within national subpopulations. We studied 955 unrelated individuals of local ancestry from nine Scottish rural regions and the urban center of Edinburgh, as well as 96 unrelated individuals from the general U.K. population. Despite little overall differentiation on the basis of allele frequencies, there were clear differences among subpopulations in the extent of pairwise LD, measured between a subset of X-linked markers, that reflected presumed differences in the depths of the underlying genealogies within these subpopulations. Therefore, there are strategic advantages in studying rural subpopulations, in terms of increased power and reduced cost, that are lost by sampling across regions or within urban populations. Similar rural-urban contrasts are likely to exist in many other populations with stable rural subpopulations, which could influence the design of genetic association studies and national biobank data collections.

Persistence of butterfly populations in fragmented habitats along urban density gradients: motility helps

PubMed Central

Rochat, E; Manel, S; Deschamps-Cottin, M; Widmer, I; Joost, S

2017-01-01

In a simulation study of genotypes conducted over 100 generations for more than 1600 butterfly’s individuals, we evaluate how the increase of anthropogenic fragmentation and reduction of habitat size along urbanisation gradients (from 7 to 59% of impervious land cover) influences genetic diversity and population persistence in butterfly species. We show that in areas characterised by a high urbanisation rate (>56% impervious land cover), a large decrease of both genetic diversity (loss of 60–80% of initial observed heterozygosity) and population size (loss of 70–90% of individuals) is observed over time. This is confirmed by empirical data available for the mobile butterfly species Pieris rapae in a subpart of the study area. Comparing simulated data for P. rapae with its normal dispersal ability and with a reduced dispersal ability, we also show that a higher dispersal ability can be an advantage to survive in an urban or highly fragmented environment. The results obtained here suggest that it is of high importance to account for population persistence, and confirm that it is crucial to maintain habitat size and connectivity in the context of land-use planning. PMID:28792492

Density-associated recruitment mediates coral population dynamics on a coral reef

NASA Astrophysics Data System (ADS)

Bramanti, Lorenzo; Edmunds, Peter J.

2016-06-01

Theory suggests that density-associated processes can modulate community resilience following declines in population size. Here, we demonstrate density-associated processes in two scleractinian populations on the outer reef of Moorea, French Polynesia, that are rapidly increasing in size following the effects of two catastrophic disturbances. Between 2006 and 2010, predation by the corallivorous crown-of-thorns sea star reduced coral cover by 93 %; in 2010, the dead coral skeletons were removed by a cyclone, and in 2011 and 2012, high coral recruitment initiated population recovery. Coral recruitment was associated with coral cover, but the relationship differed between two coral genera that are almost exclusively broadcast spawners in Moorea. Acroporids recruited at low densities, and the density of recruits was positively associated with cover of Acropora, whereas pocilloporids recruited at high densities, and densities of their recruits were negatively associated with cover of Pocillopora. Together, our results suggest that associations between adult cover and density of both juveniles and recruits can mediate rapid coral community recovery after large disturbances. The difference between taxa in sign of the relationships between recruit density and coral cover indicate that they reflect contrasting mechanisms with the potential to mediate temporal shifts in taxonomic composition of coral communities.

Trojan Tour and Rendezvous (TTR): A New Frontiers Mission to Conduct the First Detailed Reconnaissance of the Jupiter Trojan Asteroids

NASA Astrophysics Data System (ADS)

Bell, James F.; Olkin, Cathy; Castillo-Rogez, Julie

2015-11-01

Among the most potentially diagnostic but least explored populations of small bodies are the Jupiter Trojan asteroids, which orbit at ~5 AU in the L4 and L5 Lagrange points of Jupiter. The Trojans provide a unique perspective on solar system history, because their locations and physical, compositional, and mineralogic properties preserve evidence for important gravitational interactions among the giant planets. The locations and orbital properties of more than 6200 Jupiter Trojans are now known, but that is likely only a small fraction of a population of up to ~1e6 Trojans >1 km in size. The Trojans are hypothesized to be either former KBOs scattered into the inner solar system by early giant planet migration and then trapped in L4 and L5, or bodies formed near 5 AU in a more quiescent early solar system.Important Planetary Decadal Survey questions that can be addressed by studying the Trojans include: (a) How did the giant planets and their satellite systems accrete, and is there evidence that they migrated to new orbital positions? (b) What is the relationship between large and small KBOs? Is the small population derived by impact disruption of the large one? (c) What kinds of surface evolution, radiation chemistry, and surface-atmosphere interactions occur on distant icy primitive bodies? And (d) What are the sources of asteroid groups (Trojans and Centaurs) that remain to be explored by spacecraft?Here we describe the Trojan Tour and Rendezvous (TTR) New Frontiers mission concept, which is designed to answer these Decadal questions and to test hypotheses for early giant planet migration and solar system evolution. Via close flybys of many of these objects, and orbital characterization of at least one large Trojan, TTR will enable the initial up-close exploration of this population. Our primary mission goals are to characterize the overall surface geology, geochemistry and mineralogy of these worlds; to characterize their internal structure and dynamical properties; to investigate the nature, sources and history of activity on these bodies; and to explore the diversity of the broader Trojan asteroid population.

Evidence for label-retaining tumour-initiating cells in human glioblastoma

PubMed Central

Deleyrolle, Loic P.; Harding, Angus; Cato, Kathleen; Siebzehnrubl, Florian A.; Rahman, Maryam; Azari, Hassan; Olson, Sarah; Gabrielli, Brian; Osborne, Geoffrey; Vescovi, Angelo

2011-01-01

Individual tumour cells display diverse functional behaviours in terms of proliferation rate, cell–cell interactions, metastatic potential and sensitivity to therapy. Moreover, sequencing studies have demonstrated surprising levels of genetic diversity between individual patient tumours of the same type. Tumour heterogeneity presents a significant therapeutic challenge as diverse cell types within a tumour can respond differently to therapies, and inter-patient heterogeneity may prevent the development of general treatments for cancer. One strategy that may help overcome tumour heterogeneity is the identification of tumour sub-populations that drive specific disease pathologies for the development of therapies targeting these clinically relevant sub-populations. Here, we have identified a dye-retaining brain tumour population that displays all the hallmarks of a tumour-initiating sub-population. Using a limiting dilution transplantation assay in immunocompromised mice, label-retaining brain tumour cells display elevated tumour-initiation properties relative to the bulk population. Importantly, tumours generated from these label-retaining cells exhibit all the pathological features of the primary disease. Together, these findings confirm dye-retaining brain tumour cells exhibit tumour-initiation ability and are therefore viable targets for the development of therapeutics targeting this sub-population. PMID:21515906

Decadal climate prediction in the large ensemble limit

NASA Astrophysics Data System (ADS)

Yeager, S. G.; Rosenbloom, N. A.; Strand, G.; Lindsay, K. T.; Danabasoglu, G.; Karspeck, A. R.; Bates, S. C.; Meehl, G. A.

2017-12-01

In order to quantify the benefits of initialization for climate prediction on decadal timescales, two parallel sets of historical simulations are required: one "initialized" ensemble that incorporates observations of past climate states and one "uninitialized" ensemble whose internal climate variations evolve freely and without synchronicity. In the large ensemble limit, ensemble averaging isolates potentially predictable forced and internal variance components in the "initialized" set, but only the forced variance remains after averaging the "uninitialized" set. The ensemble size needed to achieve this variance decomposition, and to robustly distinguish initialized from uninitialized decadal predictions, remains poorly constrained. We examine a large ensemble (LE) of initialized decadal prediction (DP) experiments carried out using the Community Earth System Model (CESM). This 40-member CESM-DP-LE set of experiments represents the "initialized" complement to the CESM large ensemble of 20th century runs (CESM-LE) documented in Kay et al. (2015). Both simulation sets share the same model configuration, historical radiative forcings, and large ensemble sizes. The twin experiments afford an unprecedented opportunity to explore the sensitivity of DP skill assessment, and in particular the skill enhancement associated with initialization, to ensemble size. This talk will highlight the benefits of a large ensemble size for initialized predictions of seasonal climate over land in the Atlantic sector as well as predictions of shifts in the likelihood of climate extremes that have large societal impact.

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

Beauge, C.; Nesvorny, D.

Doppler and transit observations of exoplanets show a pile-up of Jupiter-size planets in orbits with a 3 day period. A fraction of these hot Jupiters have retrograde orbits with respect to the parent star's rotation, as evidenced by the measurements of the Rossiter-McLaughlin effect. To explain these observations we performed a series of numerical integrations of planet scattering followed by the tidal circularization and migration of planets that evolved into highly eccentric orbits. We considered planetary systems having three and four planets initially placed in successive mean-motion resonances, although the angles were taken randomly to ensure orbital instability in shortmore » timescales. The simulations included the tidal and relativistic effects, and precession due to stellar oblateness. Our results show the formation of two distinct populations of hot Jupiters. The inner population (Population I) is characterized by semimajor axis a < 0.03 AU and mainly formed in the systems where no planetary ejections occurred. Our follow-up integrations showed that this population was transient, with most planets falling inside the Roche radius of the star in <1 Gyr. The outer population of hot Jupiters (Population II) formed in systems where at least one planet was ejected into interstellar space. This population survives the effects of tides over >1 Gyr and fits nicely the observed 3 day pile-up. A comparison between our three-planet and four-planet runs shows that the formation of hot Jupiters is more likely in systems with more initial planets. Due to the large-scale chaoticity that dominates the evolution, high eccentricities and/or high inclinations are generated mainly by close encounters between the planets and not by secular perturbations (Kozai or otherwise). The relative proportion of retrograde planets seems of be dependent on the stellar age. Both the distribution of almost aligned systems and the simulated 3 day pile-up also fit observations better in our four-planet simulations. This may suggest that the planetary systems with observed hot Jupiters were originally rich in the number of planets, some of which were ejected. In a broad perspective, our work therefore hints on an unexpected link between the hot Jupiters and recently discovered free floating planets.« less

The Vietnam Initiative on Zoonotic Infections (VIZIONS): A Strategic Approach to Studying Emerging Zoonotic Infectious Diseases.

PubMed

Rabaa, Maia A; Tue, Ngo Tri; Phuc, Tran My; Carrique-Mas, Juan; Saylors, Karen; Cotten, Matthew; Bryant, Juliet E; Nghia, Ho Dang Trung; Cuong, Nguyen Van; Pham, Hong Anh; Berto, Alessandra; Phat, Voong Vinh; Dung, Tran Thi Ngoc; Bao, Long Hoang; Hoa, Ngo Thi; Wertheim, Heiman; Nadjm, Behzad; Monagin, Corina; van Doorn, H Rogier; Rahman, Motiur; Tra, My Phan Vu; Campbell, James I; Boni, Maciej F; Tam, Pham Thi Thanh; van der Hoek, Lia; Simmonds, Peter; Rambaut, Andrew; Toan, Tran Khanh; Van Vinh Chau, Nguyen; Hien, Tran Tinh; Wolfe, Nathan; Farrar, Jeremy J; Thwaites, Guy; Kellam, Paul; Woolhouse, Mark E J; Baker, Stephen

2015-12-01

The effect of newly emerging or re-emerging infectious diseases of zoonotic origin in human populations can be potentially catastrophic, and large-scale investigations of such diseases are highly challenging. The monitoring of emergence events is subject to ascertainment bias, whether at the level of species discovery, emerging disease events, or disease outbreaks in human populations. Disease surveillance is generally performed post hoc, driven by a response to recent events and by the availability of detection and identification technologies. Additionally, the inventory of pathogens that exist in mammalian and other reservoirs is incomplete, and identifying those with the potential to cause disease in humans is rarely possible in advance. A major step in understanding the burden and diversity of zoonotic infections, the local behavioral and demographic risks of infection, and the risk of emergence of these pathogens in human populations is to establish surveillance networks in populations that maintain regular contact with diverse animal populations, and to simultaneously characterize pathogen diversity in human and animal populations. Vietnam has been an epicenter of disease emergence over the last decade, and practices at the human/animal interface may facilitate the likelihood of spillover of zoonotic pathogens into humans. To tackle the scientific issues surrounding the origins and emergence of zoonotic infections in Vietnam, we have established The Vietnam Initiative on Zoonotic Infections (VIZIONS). This countrywide project, in which several international institutions collaborate with Vietnamese organizations, is combining clinical data, epidemiology, high-throughput sequencing, and social sciences to address relevant one-health questions. Here, we describe the primary aims of the project, the infrastructure established to address our scientific questions, and the current status of the project. Our principal objective is to develop an integrated approach to the surveillance of pathogens circulating in both human and animal populations and assess how frequently they are exchanged. This infrastructure will facilitate systematic investigations of pathogen ecology and evolution, enhance understanding of viral cross-species transmission events, and identify relevant risk factors and drivers of zoonotic disease emergence.

Fifty communities putting prevention to work: accelerating chronic disease prevention through policy, systems and environmental change.

PubMed

Bunnell, Rebecca; O'Neil, Dara; Soler, Robin; Payne, Rebecca; Giles, Wayne H; Collins, Janet; Bauer, Ursula

2012-10-01

The burden of preventable chronic diseases is straining our nation's health and economy. Diseases caused by obesity and tobacco use account for the largest portions of this preventable burden. CDC funded 50 communities in 2010 to implement policy, systems, and environmental (PSE) interventions in a 2-year initiative. Funded communities developed PSE plans to reduce obesity, tobacco use, and second-hand smoke exposure for their combined 55 million residents. Community outcome objectives and milestones were categorized by PSE interventions as they related to media, access, promotion, pricing, and social support. Communities estimated population reach based on their jurisdiction's census data and target populations. The average proportion of each community's population that was reached was calculated for each intervention category. Outcome objectives that were achieved within 12 months of program initiation were identified from routine program records. The average proportion of a community's jurisdictional population reached by a specific intervention varied across interventions. Mean population reach for obesity-prevention interventions was estimated at 35%, with 14 (26%) interventions covering over 50% of the jurisdictional populations. For tobacco prevention, mean population reach was estimated at 67%, with 16 (84%) interventions covering more than 50% of the jurisdictional populations. Within 12 months, communities advanced over one-third of their obesity and tobacco-use prevention strategies. Tobacco interventions appeared to have higher potential population reach than obesity interventions within this initiative. Findings on the progress and potential reach of this major initiative may help inform future chronic disease prevention efforts.

Assessing power of large river fish monitoring programs to detect population changes: the Missouri River sturgeon example

USGS Publications Warehouse

Wildhaber, M.L.; Holan, S.H.; Bryan, J.L.; Gladish, D.W.; Ellersieck, M.

2011-01-01

In 2003, the US Army Corps of Engineers initiated the Pallid Sturgeon Population Assessment Program (PSPAP) to monitor pallid sturgeon and the fish community of the Missouri River. The power analysis of PSPAP presented here was conducted to guide sampling design and effort decisions. The PSPAP sampling design has a nested structure with multiple gear subsamples within a river bend. Power analyses were based on a normal linear mixed model, using a mixed cell means approach, with variance estimates from the original data. It was found that, at current effort levels, at least 20 years for pallid and 10 years for shovelnose sturgeon is needed to detect a 5% annual decline. Modified bootstrap simulations suggest power estimates from the original data are conservative due to excessive zero fish counts. In general, the approach presented is applicable to a wide array of animal monitoring programs.

HPV Vaccine and Latino Immigrant Parents: If They Offer It, We Will Get It

PubMed Central

Genoff, Margaux; Gonzalez, Cynthia; Shuk, Elyse; Gany, Francesca

2015-01-01

HPV vaccination rates remain low in the fast growing Latino children population while we continue to observe large HPV-associated cancer disparities in the Latino population. In this study, we sought to elucidate Latino immigrant parents’ barriers to obtaining the HPV vaccine for their children. Five focus groups were conducted with Latino immigrant parents of minors (i.e., 9–17 year old) who had not yet initiated the HPV vaccine series. Three major findings were identified from the focus groups: (1) low levels of awareness and knowledge of HPV and the HPV vaccine, (2) high confidence that parent can get the vaccine for their eligible child and (3) lack of provider recommendation as the main barrier to vaccination. Children of Latino immigrant parents could benefit from increased provider recommendation for the HPV vaccine while providing tailored HPV information to parents. PMID:26001843

Evolutionary fate of memory-one strategies in repeated prisoner's dilemma game in structured populations

NASA Astrophysics Data System (ADS)

Liu, Xu-Sheng; Wu, Zhi-Xi; Chen, Michael Z. Q.; Guan, Jian-Yue

2017-07-01

We study evolutionary spatial prisoner's dilemma game involving a one-step memory mechanism of the individuals whenever making strategy updating. In particular, during the process of strategy updating, each individual keeps in mind all the outcome of the action pairs adopted by himself and each of his neighbors in the last interaction, and according to which the individuals decide what actions they will take in the next round. Computer simulation results imply that win-stay-lose-shift like strategy win out of the memory-one strategy set in the stationary state. This result is robust in a large range of the payoff parameter, and does not depend on the initial state of the system. Furthermore, theoretical analysis with mean field and quasi-static approximation predict the same result. Thus, our studies suggest that win-stay-lose-shift like strategy is a stable dominant strategy in repeated prisoner's dilemma game in homogeneous structured populations.

Outreach Strategies to Recruit Low-Income African American Men to Participate in Health Promotion Programs and Research: Lessons From the Men of Color Health Awareness (MOCHA) Project.

PubMed

Graham, Louis F; Scott, Lamont; Lopeyok, Erus; Douglas, Henry; Gubrium, Aline; Buchanan, David

2018-04-01

African American men continue to bear a disproportionate share of the burden of disease. Engaging these men in health research and health promotion programs-especially lower-income, African American men who are vulnerable to chronic disease conditions such as obesity and heart disease-has historically proven quite difficult for researchers and public health practitioners. The few effective outreach strategies identified in the literature to date are largely limited to recruiting through hospital clinics, churches, and barbershops. The Men of Color Health Awareness (MOCHA) project is a grassroots, community-driven initiative that has developed a number of innovative outreach strategies. After describing these strategies, we present data on the demographic and health characteristics of the population reached using these methods, which indicate that MOCHA has been highly effective in reaching this population of men.

[In vitro fertilization at the Erasme Hospital: 10 years and 1000 pregnancies later...].

PubMed

Englert, Y; Van den Bergh, M; Delbaere, A; Devreker, F; Koenig, I; Hannes, M; Emiliani, S; Biramane, J; Vannin, A S; Govaerts, I; Holoye, A; Revelard, P

1999-10-01

This contribution summarize ten years of in vitro fertilization of clinical work. Activity growth, improvements of results (mean fertilization rate increased from 45% to 58%, fertilization failure dropped from 18% to 7%, pregnancy chances gains 9% to reach 44% per trial) and new treatments possibilities (severe male infertility) thanks to the ICSI technic were the major characteristics of this last ten years. The original anonymous oocyte donation program with donors permutation initiated as soon as 1990 has imposed itself due to it's exceptional efficiency with a pregnancy rate of 95% per oocyte pick up on a population of 46 donors and 145 recipient cycles. Thanks to the large population studied (4028 cycles, 1071 pregnancies), the tendencies in human fecundity (impact of age) and the risks linked to multiples pregnancies could be highlighted, stressing the importance of future developments presented in the other contributions following this general presentation of results.

Conceptual data modeling of wildlife response indicators to ecosystem change in the Arctic

USGS Publications Warehouse

Walworth, Dennis; Pearce, John M.

2015-08-06

Large research studies are often challenged to effectively expose and document the types of information being collected and the reasons for data collection across what are often a diverse cadre of investigators of differing disciplines. We applied concepts from the field of information or data modeling to the U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative to prototype an application of information modeling. The USGS CAE initiative is collecting information from marine and terrestrial environments in Alaska to identify and understand the links between rapid physical changes in the Arctic and response of wildlife populations to these ecosystem changes. An associated need is to understand how data collection strategies are informing the overall science initiative and facilitating communication of those strategies to a wide audience. We explored the use of conceptual data modeling to provide a method by which to document, describe, and visually communicate both enterprise and study level data; provide a simple means to analyze commonalities and differences in data acquisition strategies between studies; and provide a tool for discussing those strategies among researchers and managers.

The corporate role in reducing disparities: initiatives under way at Verizon.

PubMed

Izlar, Audrietta C

2011-10-01

Major US employers have great influence on the health care system because of the large number of employees for whom they provide health benefits and the billions of dollars they spend on health care. These companies must find ways to promote and improve health and health care, including by addressing racial and ethnic disparities. The communications company Verizon 38 percent of whose workforce is made up of racial and ethnic minorities, does so through a variety of initiatives to educate employees and to partner with health plans to increase screenings, care management, and other interventions. These initiatives include on-site mammography screening for employees; mailings that describe heightened breast cancer risks for minority populations; and data analysis to determine whether special programs should be put in place to target cardiovascular and other disease risks for racial and ethnic minorities. Between 200 and 300 female employees each year for the past three years have been screened at Verizon for breast cancer as a result, and the company is carrying out additional analyses to determine the impact on morbidity, mortality, and spending for that and other programs.

Higher anti-depressant dose and major adverse outcomes in moderate chronic kidney disease: a retrospective population-based study

PubMed Central

2014-01-01

Background Many older patients have chronic kidney disease (CKD), and a lower dose of anti-depressants paroxetine, mirtazapine and venlafaxine is recommended in patients with CKD to prevent drug accumulation from reduced elimination. Using information available in large population-based healthcare administrative databases, we conducted this study to determine if ignoring the recommendation and prescribing a higher versus lower dose of anti-depressants associates with a higher risk of adverse events. Methods We conducted a population-based cohort study to describe the 30-day risk of delirium in older adults who initiated a higher vs. lower dose of these three anti-depressants in routine care. We defined delirium using the best proxy available in our data sources - hospitalization with an urgent head computed tomography (CT) scan. We determined if CKD status modified the association between anti-depressant dose and outcome, and examined the secondary outcome of 30 day all-cause mortality. We used multivariable logistic regression analyses to estimate adjusted odds ratios (relative risk (RR)) and 95% confidence intervals. Results We identified adults (mean age 75) in Ontario who started a new study anti-depressant at a higher dose (n = 36,651; 31%) or lower dose (n = 81,160; 69%). Initiating a higher vs. lower dose was not associated with an increased risk of hospitalization with head CT (1.09% vs. 1.27% (adjusted RR 0.90; 95% CI, 0.80 to 1.02), but was associated with a lower risk of all-cause mortality (0.76% vs. 0.97% RR 0.82; 95% CI, 0.71 to 0.95). Neither of these relative risks were modified by the presence of CKD (p = 0.16, 0.68, respectively). Conclusions We did not observe an increase in two adverse outcomes when study anti-depressants were initiated at a higher dose in elderly patients with moderate CKD. Contrary to our hypothesis, the 30-day risk of mortality was lower when a higher versus lower dose of anti-depressant was initiated in these patients, a finding which requires corroboration and further study. PMID:24884589

Chimeralike states in two distinct groups of identical populations of coupled Stuart-Landau oscillators

NASA Astrophysics Data System (ADS)

Premalatha, K.; Chandrasekar, V. K.; Senthilvelan, M.; Lakshmanan, M.

2017-02-01

We show the existence of chimeralike states in two distinct groups of identical populations of globally coupled Stuart-Landau oscillators. The existence of chimeralike states occurs only for a small range of frequency difference between the two populations, and these states disappear for an increase of mismatch between the frequencies. Here the chimeralike states are characterized by the synchronized oscillations in one population and desynchronized oscillations in another population. We also find that such states observed in two distinct groups of identical populations of nonlocally coupled oscillators are different from the above case in which coexisting domains of synchronized and desynchronized oscillations are observed in one population and the second population exhibits synchronized oscillations for spatially prepared initial conditions. Perturbation from such spatially prepared initial condition leads to the existence of imperfectly synchronized states. An imperfectly synchronized state represents the existence of solitary oscillators which escape from the synchronized group in population I and synchronized oscillations in population II. Also the existence of chimera state is independent of the increase of frequency mismatch between the populations. We also find the coexistence of different dynamical states with respect to different initial conditions, which causes multistability in the globally coupled system. In the case of nonlocal coupling, the system does not show multistability except in the cluster state region.

Transformational adaptation when incremental adaptations to climate change are insufficient

PubMed Central

Kates, Robert W.; Travis, William R.; Wilbanks, Thomas J.

2012-01-01

All human–environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations. PMID:22509036

Transformational adaptation when incremental adaptations to climate change are insufficient.

PubMed

Kates, Robert W; Travis, William R; Wilbanks, Thomas J

2012-05-08

All human-environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations.

The prospective role of personal health records in streamlining and accelerating the disability determination process.

PubMed

Horan, Thomas A; Daniels, Susan M; Feldman, Sue S

2009-07-01

The disability community could benefit significantly from the widespread adoption of health information technology, in particular from its ability to streamline and accelerate processing of the estimated 3 million disability benefits applications filed with the Social Security Administration each year. Disability determination is an inefficient, largely paper-based process requiring large volumes of clinical data compiled from multiple provider sources. That, coupled with a lack of transparency within the process, adds unnecessary delays and expense. The objective of this paper is to outline the case for how personal health records, particularly those populated with information from provider-held electronic health records and payer claims data, offer a means to achieve financial savings from shortened disability determination processes, as well as a tool for disability health self-management and care coordination. Drawing from research and policy forums and testimony before the American Health Information Community, the importance of including the disability community as the nation moves forward with health information technology initiatives is explored. Our research suggests that systemwide improvements such as the Nationwide Health Information Network and other such health information technology initiatives could be used to bring benefits to the disability community. The time has come to use health information technology initiatives so that federal policy makers can takes steps to reduce the inefficiencies in the Social Security Administration disability determination process while improving the program's value to those who need it the most.

Low-Mass Star Formation and the Initial Mass Function in Young Clusters

NASA Astrophysics Data System (ADS)

Luhman, Kevin Lee

I have used optical and near-infrared spectroscopy and imaging to measure spectral types and luminosities for young (/tau<10 Myr), embedded (AV=0[-]50), low-mass (0.1-1 Msolar) stars in three nearby (d<300 pc) clusters: L1495E, IC 348, and ρ Ophiuchi. In conjunction with theoretical evolutionary tracks, I have derived the star formation history and initial mass function for each stellar population. A large number of brown dwarf candidates have been identified in the photometry, several of which are confirmed through spectroscopy. Finally, I have measured the frequency and survival times of circumstellar disks and investigated the photometric and spectroscopic properties of protostars. In S 2, I apply observational tests to the available sets of evolutionary models for low-mass stars, concluding that the calculations of D'Antona & Mazzitelli are preferred for the range of masses and ages considered here. In S 3 and S 4, I examine in detail the spectroscopic characteristics and substellar nature of two brown dwarf candidates. The study then expands to include the populations within the clusters L1495E (S 5), IC 348 (S 6), and ρ Ophiuchi (S 7). In S 8, I briefly discuss the past, present, and future of scientific research related to this thesis.

Hospital Community Benefit in the Context of the Larger Public Health System: A State-Level Analysis of Hospital and Governmental Public Health Spending Across the United States.

PubMed

Singh, Simone R; Bakken, Erik; Kindig, David A; Young, Gary J

2016-01-01

Achieving meaningful population health improvements has become a priority for communities across the United States, yet funding to sustain multisector initiatives is frequently not available. One potential source of funding for population health initiatives is the community benefit expenditures that are required of nonprofit hospitals to maintain their tax-exempt status. In this article, we explore the importance of nonprofit hospitals' community benefit dollars as a funding source for population health. Hospitals' community benefit expenditures were obtained from their 2009 IRS (Internal Revenue Service) Form 990 Schedule H and complemented with data on state and local public health spending from the Association of State and Territorial Health Officials and the National Association of County & City Health Officials. Key measures included indicators of hospitals' community health spending and governmental public health spending, all aggregated to the state level. Univariate and bivariate statistics were used to describe how much hospitals spent on programs and activities for the community at large and to understand the relationship between hospitals' spending and the expenditures of state and local health departments. Tax-exempt hospitals spent a median of $130 per capita on community benefit activities, of which almost $11 went toward community health improvement and community-building activities. In comparison, median state and local health department spending amounted to $82 and $48 per capita, respectively. Hospitals' spending thus contributed an additional 9% to the resources available for population health to state and local health departments. Spending, however, varied widely by state and was unrelated to governmental public health spending. Moreover, adding hospitals' spending to the financial resources available to governmental public health agencies did not reduce existing inequalities in population health funding across states. Hospitals' community health investments represent an important source for public health activities, yet inequalities in the availability of funding across communities remain.

Optimal H1N1 vaccination strategies based on self-interest versus group interest.

PubMed

Shim, Eunha; Meyers, Lauren Ancel; Galvani, Alison P

2011-02-25

Influenza vaccination is vital for reducing H1N1 infection-mediated morbidity and mortality. To reduce transmission and achieve herd immunity during the initial 2009-2010 pandemic season, the US Centers for Disease Control and Prevention (CDC) recommended that initial priority for H1N1 vaccines be given to individuals under age 25, as these individuals are more likely to spread influenza than older adults. However, due to significant delay in vaccine delivery for the H1N1 influenza pandemic, a large fraction of population was exposed to the H1N1 virus and thereby obtained immunity prior to the wide availability of vaccines. This exposure affects the spread of the disease and needs to be considered when prioritizing vaccine distribution. To determine optimal H1N1 vaccine distributions based on individual self-interest versus population interest, we constructed a game theoretical age-structured model of influenza transmission and considered the impact of delayed vaccination. Our results indicate that if individuals decide to vaccinate according to self-interest, the resulting optimal vaccination strategy would prioritize adults of age 25 to 49 followed by either preschool-age children before the pandemic peak or older adults (age 50-64) at the pandemic peak. In contrast, the vaccine allocation strategy that is optimal for the population as a whole would prioritize individuals of ages 5 to 64 to curb a growing pandemic regardless of the timing of the vaccination program. Our results indicate that for a delayed vaccine distribution, the priorities that are optimal at a population level do not align with those that are optimal according to individual self-interest. Moreover, the discordance between the optimal vaccine distributions based on individual self-interest and those based on population interest is even more pronounced when vaccine availability is delayed. To determine optimal vaccine allocation for pandemic influenza, public health agencies need to consider both the changes in infection risks among age groups and expected patterns of adherence.

Genome-wide association study identifies three key loci for high mesocarp oil content in perennial crop oil palm

PubMed Central

Teh, Chee-Keng; Ong, Ai-Ling; Kwong, Qi-Bin; Apparow, Sukganah; Chew, Fook-Tim; Mayes, Sean; Mohamed, Mohaimi; Appleton, David; Kulaveerasingam, Harikrishna

2016-01-01

GWAS in out-crossing perennial crops is typically limited by insufficient marker density to account for population diversity and effects of population structure resulting in high false positive rates. The perennial crop oil palm is the most productive oil crop. We performed GWAS for oil-to-dry-mesocarp content (O/DM) on 2,045 genotyped tenera palms using 200K SNPs that were selected based on the short-range linkage disequilibrium distance, which is inherent with long breeding cycles and heterogeneous breeding populations. Eighty loci were significantly associated with O/DM (p ≤ 10−4) and three key signals were found. We then evaluated the progeny of a Deli x AVROS breeding trial and a 4% higher O/DM was observed amongst those having the beneficial genotypes at two of the three key loci (p < 0.05). We have initiated MAS and large-scale planting of elite dura and pisifera parents to generate the new commercial tenera palms with higher O/DM potential. PMID:26743827

Mexico's Seguro Popular Appears To Have Helped Reduce The Risk Of Preterm Delivery Among Women With Low Education.

PubMed

Strouse, Carly; Perez-Cuevas, Ricardo; Lahiff, Maureen; Walsh, Julia; Guendelman, Sylvia

2016-01-01

Beginning in 2001 Mexico established Seguro Popular, a health insurance scheme aimed at providing coverage to its large population of uninsured people. While recent studies have evaluated the health benefits of Seguro Popular, evidence on perinatal health outcomes is lacking. We conducted a population-based study using Mexican birth certificate data for 2010 to assess the relationship between enrollment in Seguro Popular and preterm delivery among first-time mothers with singleton births in Mexico. Seguro Popular enrollees with no formal education had a far greater reduction in risk of preterm delivery, while enrollees with any formal education experienced only slight reduction in risk, after maternal age, marital status, education level, mode of delivery, and trimester in which prenatal care was initiated were controlled for. Seguro Popular appears to facilitate access to health services among mothers with low levels of education, reducing their risk for preterm delivery. Providing broad-scale health insurance coverage may help improve perinatal health outcomes in this vulnerable population. Project HOPE—The People-to-People Health Foundation, Inc.

Orbiting space debris: Dangers, measurement and mitigation

NASA Astrophysics Data System (ADS)

McNutt, Ross T.

1992-06-01

Space debris is a growing environmental problem. Accumulation of objects in earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, United States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical and diplomatic components. Actions need to be taken now to: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the loss of critical space systems such as the space shuttle or the space station.

Laparoscopic vasectomy in African savannah elephant (Loxodonta africana); surgical technique and results.

PubMed

Marais, Hendrik J; Hendrickson, Dean A; Stetter, Mark; Zuba, Jeffery R; Penning, Mark; Siegal-Willott, Jess; Hardy, Christine

2013-12-01

Several small, enclosed reserves in southern Africa are experiencing significant elephant population growth, which has resulted in associated environmental damage and changes in biodiversity. Although several techniques exist to control elephant populations, e.g., culling, relocation, and immunocontraception, the technique of laparoscopic vasectomy of free-ranging bull elephants was investigated. Bilateral vasectomies were performed in 45 elephants. Of these elephants, one died within 24 hr of recovery and two had complications during surgery but recovered uneventfully. Histologic examination confirmed the resected tissue as ductus deferens in all the bulls. Most animals recovered uneventfully and showed no abnormal behavior after surgery. Complications recorded included incisional dehiscence, 1 full-thickness and 2 partial-thickness lacerations of the large intestine, and initial sling-associated complications, for example, deep radial nerve paresis. One bull was found dead 6 weeks after surgery without showing any prior abnormal signs. Vasectomy in free-ranging African bull elephants may be effectively performed in their normal environment. The surgical procedure can be used as a realistic population management tool in free-ranging elephants without major anesthetic, surgical, or postoperative complications.

Concurrent Isolation of 3 Distinct Cardiac Stem Cell Populations From a Single Human Heart Biopsy.

PubMed

Monsanto, Megan M; White, Kevin S; Kim, Taeyong; Wang, Bingyan J; Fisher, Kristina; Ilves, Kelli; Khalafalla, Farid G; Casillas, Alexandria; Broughton, Kathleen; Mohsin, Sadia; Dembitsky, Walter P; Sussman, Mark A

2017-07-07

The relative actions and synergism between distinct myocardial-derived stem cell populations remain obscure. Ongoing debates on optimal cell population(s) for treatment of heart failure prompted implementation of a protocol for isolation of multiple stem cell populations from a single myocardial tissue sample to develop new insights for achieving myocardial regeneration. Establish a robust cardiac stem cell isolation and culture protocol to consistently generate 3 distinct stem cell populations from a single human heart biopsy. Isolation of 3 endogenous cardiac stem cell populations was performed from human heart samples routinely discarded during implantation of a left ventricular assist device. Tissue explants were mechanically minced into 1 mm 3 pieces to minimize time exposure to collagenase digestion and preserve cell viability. Centrifugation removes large cardiomyocytes and tissue debris producing a single cell suspension that is sorted using magnetic-activated cell sorting technology. Initial sorting is based on tyrosine-protein kinase Kit (c-Kit) expression that enriches for 2 c-Kit + cell populations yielding a mixture of cardiac progenitor cells and endothelial progenitor cells. Flowthrough c-Kit - mesenchymal stem cells are positively selected by surface expression of markers CD90 and CD105. After 1 week of culture, the c-Kit + population is further enriched by selection for a CD133 + endothelial progenitor cell population. Persistence of respective cell surface markers in vitro is confirmed both by flow cytometry and immunocytochemistry. Three distinct cardiac cell populations with individualized phenotypic properties consistent with cardiac progenitor cells, endothelial progenitor cells, and mesenchymal stem cells can be successfully concurrently isolated and expanded from a single tissue sample derived from human heart failure patients. © 2017 American Heart Association, Inc.

Initiation Patterns of Statins in the 2 Years After Release of the 2013 American College of Cardiology/American Heart Association (ACC/AHA) Cholesterol Management Guideline in a Large US Health Plan.

PubMed

Olufade, Temitope; Zhou, Siting; Anzalone, Deborah; Kern, David M; Tunceli, Ozgur; Cziraky, Mark J; Willey, Vincent J

2017-05-04

The purpose of this study was to characterize changes in statin utilization patterns in patients newly initiated on therapy in the 2 years following the release of the 2013 American College of Cardiology/American Heart Association (ACC/AHA) cholesterol management guideline in a large US health plan population. This retrospective, observational study used administrative medical and pharmacy claims data to identify patients newly initiated on statin therapy over 4 quarters prior to and 8 quarters following the release of the guideline (average N/quarter=3596). Patients were divided into the 4 statin benefit groups (SBGs) based on risk factors and laboratory lipid levels as defined in the guideline: SBG1 (with atherosclerotic cardiovascular disease [ASCVD]; N=1046/quarter), SBG2 (without ASCVD, with low-density lipoprotein cholesterol ≥190 mg/dL; N=454/quarter), SBG3 (without ASCVD, aged 40-75 years, with diabetes mellitus, low-density lipoprotein cholesterol 70-189 mg/dL; N=1391/quarter), SBG4 (no ASCVD or diabetes mellitus, age 40-75 years, low-density lipoprotein cholesterol 70-189 mg/dL, estimated 10-year ASCVD risk of ≥7.5%; N=705/quarter). Demographic variables, statin utilization patterns, lipid levels, and comorbidities were analyzed for pre- and postguideline periods. Postguideline, gradually increased high-intensity statin initiation occurred in SBG1, SBG2, and in SBG3 patients with 10-year ASCVD risk ≥7.5%. Moderate- to high-intensity statin initiation gradually increased among SBG4 patients. Recommended-intensity statin choice changed to a greater degree among patients treated by specialty care physicians. Regarding sex, target-intensity statin initiation was lower in women in all groups before and after guideline release. Prescriber implementation of the guideline recommendations has gradually increased, with the most marked change in the increased initiation of high-intensity statins in patients with ASCVD and in those treated by a specialist. © 2017 The Authors, AstraZeneca, and HealthCore. Published on behalf of the American Heart Association, Inc., by Wiley.

Identification of cancer risk and associated behaviour: implications for social marketing campaigns for cancer prevention.

PubMed

Kippen, Rebecca; James, Erica; Ward, Bernadette; Buykx, Penny; Shamsullah, Ardel; Watson, Wendy; Chapman, Kathy

2017-08-17

Community misconception of what causes cancer is an important consideration when devising communication strategies around cancer prevention, while those initiating social marketing campaigns must decide whether to target the general population or to tailor messages for different audiences. This paper investigates the relationships between demographic characteristics, identification of selected cancer risk factors, and associated protective behaviours, to inform audience segmentation for cancer prevention social marketing. Data for this cross-sectional study (n = 3301) are derived from Cancer Council New South Wales' 2013 Cancer Prevention Survey. Descriptive statistics and logistic regression models were used to investigate the relationship between respondent demographic characteristics and identification of each of seven cancer risk factors; demographic characteristics and practice of the seven 'protective' behaviours associated with the seven cancer risk factors; and identification of cancer risk factors and practising the associated protective behaviours, controlling for demographic characteristics. More than 90% of respondents across demographic groups identified sun exposure and smoking cigarettes as moderate or large cancer risk factors. Around 80% identified passive smoking as a moderate/large risk factor, and 40-60% identified being overweight or obese, drinking alcohol, not eating enough vegetables and not eating enough fruit. Women and older respondents were more likely to identify most cancer risk factors as moderate/large, and to practise associated protective behaviours. Education was correlated with identification of smoking as a moderate/large cancer risk factor, and with four of the seven protective behaviours. Location (metropolitan/regional) and country of birth (Australia/other) were weak predictors of identification and of protective behaviours. Identification of a cancer risk factor as moderate/large was a significant predictor for five out of seven associated cancer-protective behaviours, controlling for demographic characteristics. These findings suggest a role for both audience segmentation and whole-of-population approaches in cancer-prevention social marketing campaigns. Targeted campaigns can address beliefs of younger people and men about cancer risk factors. Traditional population campaigns can enhance awareness of being overweight, alcohol consumption, and poor vegetable and fruit intake as cancer risk factors.

Effects of developmental variability on the dynamics and self-organization of cell populations

NASA Astrophysics Data System (ADS)

Prabhakara, Kaumudi H.; Gholami, Azam; Zykov, Vladimir S.; Bodenschatz, Eberhard

2017-11-01

We report experimental and theoretical results for spatiotemporal pattern formation in cell populations, where the parameters vary in space and time due to mechanisms intrinsic to the system, namely Dictyostelium discoideum (D.d.) in the starvation phase. We find that different patterns are formed when the populations are initialized at different developmental stages, or when populations at different initial developmental stages are mixed. The experimentally observed patterns can be understood with a modified Kessler-Levine model that takes into account the initial spatial heterogeneity of the cell populations and a developmental path introduced by us, i.e. the time dependence of the various biochemical parameters. The dynamics of the parameters agree with known biochemical studies. Most importantly, the modified model reproduces not only our results, but also the observations of an independent experiment published earlier. This shows that pattern formation can be used to understand and quantify the temporal evolution of the system parameters.

Steady states and outbreaks of two-phase nonlinear age-structured model of population dynamics with discrete time delay.

PubMed

Akimenko, Vitalii; Anguelov, Roumen

2017-12-01

In this paper we study the nonlinear age-structured model of a polycyclic two-phase population dynamics including delayed effect of population density growth on the mortality. Both phases are modelled as a system of initial boundary values problem for semi-linear transport equation with delay and initial problem for nonlinear delay ODE. The obtained system is studied both theoretically and numerically. Three different regimes of population dynamics for asymptotically stable states of autonomous systems are obtained in numerical experiments for the different initial values of population density. The quasi-periodical travelling wave solutions are studied numerically for the autonomous system with the different values of time delays and for the system with oscillating death rate and birth modulus. In both cases it is observed three types of travelling wave solutions: harmonic oscillations, pulse sequence and single pulse.

Radiocarbon Dating the Anthropocene

NASA Astrophysics Data System (ADS)

Chaput, M. A.; Gajewski, K. J.

2015-12-01

The Anthropocene has no agreed start date since current suggestions for its beginning range from Pre-Industrial times to the Industrial Revolution, and from the mid-twentieth century to the future. To set the boundary of the Anthropocene in geological time, we must first understand when, how and to what extent humans began altering the Earth system. One aspect of this involves reconstructing the effects of prehistoric human activity on the physical landscape. However, for global reconstructions of land use and land cover change to be more accurately interpreted in the context of human interaction with the landscape, large-scale spatio-temporal demographic changes in prehistoric populations must be known. Estimates of the relative number of prehistoric humans in different regions of the world and at different moments in time are needed. To this end, we analyze a dataset of radiocarbon dates from the Canadian Archaeological Radiocarbon Database (CARD), the Palaeolithic Database of Europe and the AustArch Database of Australia, as well as published dates from South America. This is the first time such a large quantity of dates (approximately 60,000) has been mapped and studied at a global scale. Initial results from the analysis of temporal frequency distributions of calibrated radiocarbon dates, assumed to be proportional to population density, will be discussed. The utility of radiocarbon dates in studies of the Anthropocene will be evaluated and potential links between population density and changes in atmospheric greenhouse gas concentrations, climate, migration patterning and fire frequency coincidence will be considered.

Land Change in Russia since 2000

NASA Astrophysics Data System (ADS)

de Beurs, K.; Ioffe, G.; Nefedova, T.

2010-12-01

Agricultural reform has been an important anthropogenic change process shaping landscapes in European Russia since the formal collapse of the Soviet Union at the end of 1991. Widespread land abandonment is perhaps the most evident side effect of the reform, even visible in synoptic imagery. While land abandonment as a result of the collapse of the Soviet Union is relatively well documented, few studies have investigated the unfolding process of abandonment that results from rural population declines. Russia’s population is projected to shrink by a staggering 29% by 2050 and population dynamics are predicted to play a significant role structuring rural landscapes across European Russia. While often treated as a unified whole with respect to agricultural reform, significant regional diversity exists in Russia. Official statistics at the rayon (county) level are typically skewed toward large-scale farming and farm data from important household productions are summarized into regional averages. In addition, data at sub-district level can often only be obtained by visiting rural administrators in person. Large scale official data thus need to be interpreted with caution. Here we present data collected during the summer of 2010 from representative settlements and enterprises in selected counties within the oblasts (states) of Kostroma and Samara. These field data will provide an initial overview of the economic and social state in modern rural western Russia. We will combine the field data with established socio-demographic observations as well as satellite observations at multiple scales to understand the effect of global change and to project future developments.

Chemical Evolution and History of Star Formation in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Gustafsson, Bengt

1995-07-01

Large scale processes controlling star formation and nucleosynthesis are fundamental but poorly understood. This is especially true for external galaxies. A detailed study of individual main sequence stars in the LMC Bar is proposed. The LMC is close enough to allow this, has considerable spread in stellar ages and a structure permitting identification of stellar populations and their structural features. The Bar presumably plays a dominant role in the chemical and dynamical evolution of the galaxy. Our knowledge is, at best, based on educated guesses. Still, the major population of the Bar is quite old, and many member stars are relatively evolved. The Bar seems to contain stars similar to those of Intermediate to Extreme Pop II in the Galaxy. We want to study the history of star formation, chemical evolution and initial mass function of the population dominating the Bar. We will use field stars close to the turn off point in the HR diagram. From earlier studies, we know that 250-500 such stars are available for uvby photometry in the PC field. We aim at an accuracy of 0.1 -0.2 dex in Me/H and 25% or better in relative ages. This requires an accuracy of about 0.02 mag in the uvby indices, which can be reached, taking into account errors in calibration, flat fielding, guiding and problems due to crowding. For a study of the luminosity function fainter stars will be included as well. Calibration fields are available in Omega Cen and M 67.

Persistent states in vision break universality and time invariance

PubMed Central

Wexler, Mark; Duyck, Marianne; Mamassian, Pascal

2015-01-01

Studies of perception usually emphasize processes that are largely universal across observers and—except for short-term fluctuations—stationary over time. Here we test the universality and stationarity assumptions with two families of ambiguous visual stimuli. Each stimulus can be perceived in two different ways, parameterized by two opposite directions from a continuous circular variable. A large-sample study showed that almost all observers have preferred directions or biases, with directions lying within 90 degrees of the bias direction nearly always perceived and opposite directions almost never perceived. The biases differ dramatically from one observer to the next, and although nearly every bias direction occurs in the population, the population distributions of the biases are nonuniform, featuring asymmetric peaks in the cardinal directions. The biases for the two families of stimuli are independent and have distinct population distributions. Following external perturbations and spontaneous fluctuations, the biases decay over tens of seconds toward their initial values. Persistent changes in the biases are found on time scales of several minutes to 1 hour. On scales of days to months, the biases undergo a variety of dynamical processes such as drifts, jumps, and oscillations. The global statistics of a majority of these long-term time series are well modeled as random walk processes. The measurable fluctuations of these hitherto unknown degrees of freedom show that the assumptions of universality and stationarity in perception may be unwarranted and that models of perception must include both directly observable variables as well as covert, persistent states. PMID:26627250

Opinion dynamics in two dimensions: domain coarsening leads to stable bi-polarization and anomalous scaling exponents

NASA Astrophysics Data System (ADS)

Velásquez-Rojas, F.; Vazquez, F.

2018-04-01

We study an opinion dynamics model that explores the competition between persuasion and compromise in a population of agents with nearest-neighbor interactions on a two-dimensional square lattice. Each agent can hold either a positive or a negative opinion orientation, and can have two levels of intensity—moderate and extremist. When two interacting agents have the same orientation they become extremists with persuasion probability p, while if they have opposite orientations they become moderate with compromise probability q. These updating rules lead to the formation of same-opinion domains with a coarsening dynamics that depends on the ratio r  =  p/q. The population initially evolves to a centralized state for small r, where domains are composed of moderate agents and coarsening is without surface tension, and to a bi-polarized state for large r, where domains are formed by extremist agents and coarsening is driven by curvature. Consensus in an extreme opinion is finally reached in a time that scales with the population size N and r as for small r and as for large r. Bi-polarization could be quite stable when the system falls into a striped state where agents organize into single-opinion horizontal, vertical or diagonal bands. An analysis of the stripe dynamics towards consensus allows us to obtain an approximate expression for τ, which shows that the exponent 1.64 is a result of the diffusion of the stripe interfaces combined with their roughness properties.

Close to home: An analysis of the relationship between location of residence and location of injury

PubMed Central

Haas, Barbara; Doumouras, Aristithes G.; Gomez, David; de Mestral, Charles; Boyes, Donald M.; Morrison, Laurie; Nathens, Avery B.

2015-01-01

BACKGROUND Injury surveillance is critical in identifying the need for targeted prevention initiatives. Understanding the geographic distribution of injuries facilitates matching prevention programs with the population most likely to benefit. At the population level, however, the geographic site of injury is rarely known, leading to the use of location of residence as a surrogate. To determine the accuracy of this approach, we evaluated the relationship between site of injury and of residence over a large geographic area. METHODS Data were derived from a population-based, pre-hospital registry of persons meeting triage criteria for major trauma. Patients dying at the scene or transported to hospital were included. Distance between locations of residence and of injury was calculated using geographic information system network analysis. RESULTS Among 3,280 patients (2005-2010), 88% were injured within 10 miles of home (median 0.2 miles). There were significant differences in distance between residence and location of injury based on mechanism of injury, age and hospital disposition. The large majority of injuries involving children, the elderly, pedestrians, cyclists, falls, and assaults occurred less than 10 miles from the patient's residence. Only 77% of MVC occurred within 10 miles of the patient's residence. CONCLUSION Though the majority of patients are injured less than 10 miles from their residence, the probability of injury occurring “close to home” depends on patient and injury characteristics. LEVEL OF EVIDENCE Epidemiological retrospective study. Level III. PMID:25807410

Host-pathogen metapopulation dynamics suggest high elevation refugia for boreal toads

USGS Publications Warehouse

Mosher, Brittany A.; Bailey, Larissa L.; Muths, Erin L.; Huyvaert, Kathryn P

2018-01-01

Emerging infectious diseases are an increasingly common threat to wildlife. Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease that has been linked to amphibian declines around the world. Few studies exist that explore amphibian-Bd dynamics at the landscape scale, limiting our ability to identify which factors are associated with variation in population susceptibility and to develop effective in situdisease management. Declines of boreal toads (Anaxyrus boreas boreas) in the Southern Rocky Mountains are largely attributed to chytridiomycosis but variation exists in local extinction of boreal toads across this metapopulation. Using a large-scale historic dataset, we explored several potential factors influencing disease dynamics in the boreal toad-Bd system: geographic isolation of populations, amphibian community richness, elevational differences, and habitat permanence. We found evidence that boreal toad extinction risk was lowest at high elevations where temperatures may be sub-optimal for Bd growth and where small boreal toad populations may be below the threshold needed for efficient pathogen transmission. In addition, boreal toads were more likely to recolonize high elevation sites after local extinction, again suggesting that high elevations may provide refuge from disease for boreal toads. We illustrate a modeling framework that will be useful to natural resource managers striving to make decisions in amphibian-Bdsystems. Our data suggest that in the southern Rocky Mountains high elevation sites should be prioritized for conservation initiatives like reintroductions.

Effects of Soil Type on the Damage Potential of Meloidogyne incognita on Soybean.

PubMed

Windham, G L; Barker, K R

1986-07-01

Effects of soil type on the reproduction and damage potential of Meloidogyne incognita on soybean, Glycine max (L.) Merr., were determined at five locations in North Carolina, including one site where plots with six soil types were established. M. incognita reproduced readily on a susceptible soybean cultivar in most soil types, with somewhat limited reproduction in muck soils. The relationship between initial population densities and yield varied among soil types and nematode populations. Yield losses were greatest in sandy and muck soil types, with less nematode damage occurring in the clay soil types. A North Carolina and a Georgia population of M. incognita differed greatly in their ability to reproduce on soybean and suppress growth. The North Carolina population had a moderate effect on yield in 1981 and only a slight effect in 1982. In contrast, a Georgia population severely limited soybean growth and yield at lower initial population densities in 1983, Initial population densities of the nematodes and physical and chemical edaphic factors accounted for much of the variation of soybean yield and nematode reproduction.

Most of the extant mtDNA boundaries in South and Southwest Asia were likely shaped during the initial settlement of Eurasia by anatomically modern humans

PubMed Central

Metspalu, Mait; Kivisild, Toomas; Metspalu, Ene; Parik, Jüri; Hudjashov, Georgi; Kaldma, Katrin; Serk, Piia; Karmin, Monika; Behar, Doron M; Gilbert, M Thomas P; Endicott, Phillip; Mastana, Sarabjit; Papiha, Surinder S; Skorecki, Karl; Torroni, Antonio; Villems, Richard

2004-01-01

Background Recent advances in the understanding of the maternal and paternal heritage of south and southwest Asian populations have highlighted their role in the colonization of Eurasia by anatomically modern humans. Further understanding requires a deeper insight into the topology of the branches of the Indian mtDNA phylogenetic tree, which should be contextualized within the phylogeography of the neighboring regional mtDNA variation. Accordingly, we have analyzed mtDNA control and coding region variation in 796 Indian (including both tribal and caste populations from different parts of India) and 436 Iranian mtDNAs. The results were integrated and analyzed together with published data from South, Southeast Asia and West Eurasia. Results Four new Indian-specific haplogroup M sub-clades were defined. These, in combination with two previously described haplogroups, encompass approximately one third of the haplogroup M mtDNAs in India. Their phylogeography and spread among different linguistic phyla and social strata was investigated in detail. Furthermore, the analysis of the Iranian mtDNA pool revealed patterns of limited reciprocal gene flow between Iran and the Indian sub-continent and allowed the identification of different assemblies of shared mtDNA sub-clades. Conclusions Since the initial peopling of South and West Asia by anatomically modern humans, when this region may well have provided the initial settlers who colonized much of the rest of Eurasia, the gene flow in and out of India of the maternally transmitted mtDNA has been surprisingly limited. Specifically, our analysis of the mtDNA haplogroups, which are shared between Indian and Iranian populations and exhibit coalescence ages corresponding to around the early Upper Paleolithic, indicates that they are present in India largely as Indian-specific sub-lineages. In contrast, other ancient Indian-specific variants of M and R are very rare outside the sub-continent. PMID:15339343

Comparison of Drug Utilization Patterns in Observational Data: Antiepileptic Drugs in Pediatric Patients.

PubMed

Bourgeois, Florence T; Olson, Karen L; Poduri, Annapurna; Mandl, Kenneth D

2015-10-01

Physicians require information on the comparative benefits and harms of medications for optimal treatment decisions. However, this type of data is limited, especially for pediatric patients. Our aim was to use observational data to measure and compare medication utilization patterns in a pediatric patient population. Using pharmacy claims data from a large, national-scale insurance program in the USA, we identified all patients with a diagnosis of epilepsy treated with a first-generation antiepileptic drug (carbamazepine, ethosuximide, phenobarbital, phenytoin, or valproate) or a second-generation antiepileptic drug [carbamazepine extended release (XR), gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, valproate XR, or zonisamide]. Treatment periods were defined on the basis of prescription fill dates and medication days supplied. Medication use was measured for individual antiepileptic drugs and for first-generation and second-generation drugs as groups. There were 2527 patients (54 %) who initiated therapy with first-generation antiepileptics and 2139 patients (46 %) who initiated therapy with second-generation antiepileptics. First- and second-generation drugs had the same 1-year retention rates [26 % (95 % confidence interval (CI) 24-28) and 26 % (95 % CI 25-28), respectively], and 26 % of patients (95 % CI 25-28) and 29 % of patients (95 % CI 27-31) who started on a first- or second-generation antiepileptic medication, respectively, resumed treatment with the initial drug after discontinuation. Overall, 73 % of patients (95 % CI 71-74) were treated with only one antiepileptic drug, with similar rates for patients started on first- and second-generation drugs [71 % (95 % CI 69-73) versus 74 % (95 % CI 72-76)]. Comparing drug utilization patterns in a pediatric population using observational data, we found similar rates of retention and therapeutic changes. These findings are consistent with the available comparative data and demonstrate an approach that could be extended to other drug classes and conditions in pediatric populations to examine drug effectiveness.

Interaction of Staphylococcus aureus persister cells with the host when in a persister state and following awakening.

PubMed

Mina, Elin G; Marques, Cláudia N H

2016-08-10

Persister cells, a tolerant cell sub-population, are commonly associated with chronic and recurrent infections. However, little is known about their ability to actually initiate or establish an infection, become virulent and cause pathogenicity within a host. Here we investigated whether Staphylococcus aureus persister cells initiate an infection and are recognized by macrophages, while in a persister cell status, and upon awakening due to exposure to cis-2-decenoic acid (cis-DA). Our results show that S. aureus persister cells are not able to initiate infections in A. thaliana and present significantly reduced virulence towards C. elegans compared to total populations. In contrast, awakened S. aureus persister cells are able to initiate infections in A. thaliana and in C. elegans albeit, with lower mortality than total population. Furthermore, exposure of S. aureus persister cells to cis-DA led to a loss of tolerance to ciprofloxacin, and an increase of the bacterial fluorescence to levels found in total population. In addition, macrophage engulfment of persister cells was significantly lower than engulfment of total population, both before and following awakening. Overall our findings indicate that upon awakening of a persister population the cells regain their ability to infect hosts despite the absence of an increased immune response.

Alternative fuelds in urban fleets

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

Lindsay, T.

1994-12-31

In this presentation the author addresses four main objectives. They are to: discuss programs that are driving the introduction of alternative fuels into fleet operations in urban areas around the country; define alternative fuels; quantify the present use and future projections on alternative fuel vehicles (AVFs) in the Chicago metropolitan statistical area; and discuss benefits of increased use of alternative fuels in urban areas. Factors which touch on these points include: present domestic dependence on petroleum for autos, with usage exceeding production; the large populations in urban areas which do not meet Clean Air Standards; recent legislative initiatives which givemore » guidance and aid in the adoption of such strategies.« less

White-nose Syndrome management: Report on structured decision making initiative

USGS Publications Warehouse

Szymanski, Jennifer A.; Runge, Michael C.; Parkin, Mary J.; Armstrong, Mike

2009-01-01

This report describes an analysis undertaken to assist state and federal natural resources managers in addressing the following question: What management measures should be taken this year within a given area to control the spread and minimize the effects of white-nose syndrome (WNS) on hibernating bats at the individual and population levels? The answer depends upon specific characteristics of the bat species, the hibernacula, and the syndrome itself, all of which could vary across the geographic extent of WNS and change over time. It also depends on a large number of agency and societal judgments concerning how to balance disease management against other objectives.

Public opinion by a poll process: model study and Bayesian view

NASA Astrophysics Data System (ADS)

Lee, Hyun Keun; Kim, Yong Woon

2018-05-01

We study the formation of public opinion in a poll process where the current score is open to the public. The voters are assumed to vote probabilistically for or against their own preference considering the group opinion collected up to then in the score. The poll-score probability is found to follow the beta distribution in the large polls limit. We demonstrate that various poll results, even those contradictory to the population preference, are possible with non-zero probability density and that such deviations are readily triggered by initial bias. It is mentioned that our poll model can be understood in the Bayesian viewpoint.

Early colonial health developments in Mauritius.

PubMed

Parahoo, K A

1986-01-01

The historical development of Mauritius and in particular the early developments in health care are crucial to an understanding of the contemporary health system. The introduction of major epidemic diseases through the movements of French soldiers to and from India and the immigration of indentured laborers from India account for the high mortality and morbidity rates in the 18th and 19th centuries and later. The colonial economy created and fortified the dependence on a single cash crop and on imported food. It also contributed toward the impoverization of large sections of the Mauritian population. The colonial era is also responsible for initiating a three tier system of health care.

The Resilient Infrastructure Initiative

DOE PAGES

Clifford, Megan

2016-10-01

Infrastructure is, by design, largely unnoticed until it breaks down and services fail. This includes water supplies, gas pipelines, bridges and dams, phone lines and cell towers, roads and culverts, railways, and the electric grid—all of the complex systems that keep our societies and economies running. Climate change, population growth, increased urbanization, system aging, and outdated design standards stress existing infrastructure and its ability to satisfy the rapidly changing demands from users. Here, the resilience of both physical and cyber infrastructure systems, however, is critical to a community as it prepares for, responds to, and recovers from a disaster, whethermore » natural or man-made.« less

Nursing and genetic biobanks.

PubMed

Sanner, Jennifer E; Yu, Erica; Udtha, Malini; Williams, Pamela Holtzclaw

2013-12-01

Biobanks function as vital components in genetic research, which often requires large disease-based or population-based biospecimens and clinical data to study complex or rare diseases. Genetic biobanks aim to provide resources for translational research focusing on rapidly moving scientific findings from the laboratory into health care practice. The nursing profession must evolve as genetic biobanking practices advance. Nursing involvement in genetic biobanking practices comes with a distinct set of educational, ethical, and practice competencies. In response to these growing competency standards, nursing science developed a conceptual framework and continues to study ethical considerations to guide genetic biobanking initiatives. Copyright © 2013 Elsevier Inc. All rights reserved.

Communication during an evolving seismic sequence

NASA Astrophysics Data System (ADS)

Mucciarelli, M.; Camassi, R.

2012-04-01

Since October 2011 a seismic swarm is affecting the Pollino mountain range, southern Italy. At the abstract submission date the sequence is still ongoing, with more than 500 events with M>1, at least 40 well perceived by the population and a maximum magnitude at 3.6. The area was hit by a magnitude 5.7 event in 1998 that caused one dead, some injured and widespread damage in at least six municipalities. The population main fear is that a large event could follow the seismic swarm as it occurred at L'Aquila in 2009. Among the initiatives taken by Civil Protection at national and regional level, it was decided to try to implement at local scale two communication projects that were thought for "peace time" and not for dissemination during a seismic crisis: the "Terremoto-Io non rischio" project for general public and the "EDURISK" project for school children. The main lesson learned during the first months of the activity are: 1) it is possible to take advantage of the increased awareness and risk perception from the population to attract more citizen toward topics that could go unnoticed otherwise; 2) the Civil Protection volunteers could be a very effective mean to reach a large amount of the population, provided they are carefully trained especially when children are involved; 3) the expectations about earthquake prediction raised from media without any scientific support proved to be the most difficult to be tackled: to overcome this bias risk education in "peace time" is absolutely essential; 4) door-to-door communication is perceived much better than official press release on newspapers; 5) training of volunteers must be limited to a few basic information, with special attention to the local context.

Framing Innovation: Does an Instructional Vision Help Superintendents Gain Acceptance for a Large-Scale Technology Initiative?

ERIC Educational Resources Information Center

Flanagan, Gina E.

2014-01-01

There is limited research that outlines how a superintendent's instructional vision can help to gain acceptance of a large-scale technology initiative. This study explored how superintendents gain acceptance for a large-scale technology initiative (specifically a 1:1 device program) through various leadership actions. The role of the instructional…

Self-organized cooperative behavior and critical penalty in an evolving population

NASA Astrophysics Data System (ADS)

Xu, Chen; Hui, P. M.; Yu, You-Yang; Gu, Guo-Qing

2009-10-01

The emergence of cooperation and the effectiveness of penalties among competing agents are studied via a model of evolutionary game incorporating adaptive behavior and penalties for illegal acts. For initially identical agents, a phase diagram is obtained via an analytic approach, with results in good agreement with numerical simulations. The results show that there exists a critical penalty for achieving a completely honest population and a sufficiently well-behaved initial population requires no penalty. Self-organized segregation to extreme actions emerges in the dynamics for a system with uniformly distributed initial tendencies for cooperation. After training, the penalty can be relaxed without ruining the adapted cooperative behavior. Results of our model in a population taking on the form of a 2D square lattice are also reported.

Habitat Size Optimization of the O'Neill - Glaser Economic Model for Space Solar Satellite Production

NASA Technical Reports Server (NTRS)

Curreri, Peter A.; Detweiler, Michael

2010-01-01

Creating large space habitats by launching all materials from Earth is prohibitively expensive. Using space resources and space based labor to build space solar power satellites can yield extraordinary profits after a few decades. The economic viability of this program depends on the use of space resources and space labor. To maximize the return on the investment, the early use of high density bolo habitats is required. Other shapes do not allow for the small initial scale required for a quick population increase in space. This study found that 5 Man Year, or 384 person bolo high density habitats will be the most economically feasible for a program started at year 2010 and will cause a profit by year 24 of the program, put over 45,000 people into space, and create a large system of space infrastructure for the further exploration and development of space.

Ionospheric chemical releases

NASA Technical Reports Server (NTRS)

Bernhardt, Paul A.; Scales, W. A.

1990-01-01

Ionospheric plasma density irregularities can be produced by chemical releases into the upper atmosphere. F-region plasma modification occurs by: (1) chemically enhancing the electron number density; (2) chemically reducing the electron population; or (3) physically convecting the plasma from one region to another. The three processes (production, loss, and transport) determine the effectiveness of ionospheric chemical releases in subtle and surprising ways. Initially, a chemical release produces a localized change in plasma density. Subsequent processes, however, can lead to enhanced transport in chemically modified regions. Ionospheric modifications by chemical releases excites artificial enhancements in airglow intensities by exothermic chemical reactions between the newly created plasma species. Numerical models were developed to describe the creation and evolution of large scale density irregularities and airglow clouds generated by artificial means. Experimental data compares favorably with theses models. It was found that chemical releases produce transient, large amplitude perturbations in electron density which can evolve into fine scale irregularities via nonlinear transport properties.

Urban parasitology: visceral leishmaniasis in Brazil.

PubMed

Harhay, Michael O; Olliaro, Piero L; Costa, Dorcas Lamounier; Costa, Carlos Henrique Nery

2011-09-01

Since the early 1980s, visceral leishmaniasis (VL) which is, in general, a rural zoonotic disease, has spread to the urban centers of the north, and now the south and west of Brazil. The principal drivers differ between cities, though human migration, large urban canid populations (animal reservoir), and a decidedly peripatetic and adaptable sand fly vector are the primary forces. The exact number of urban cases remains unclear as a result of challenges with surveillance. However, the number of urban cases registered continues to increase annually. Most control initiatives (e.g. culling infected dogs and household spraying to kill the sand fly) could be effective, but have proven hard to maintain at large scales due to logistical, financial and other reasons. In this article, the urbanization of VL in Brazil is reviewed, touching on these and other topics related to controlling VL within and outside Brazil. Copyright © 2011 Elsevier Ltd. All rights reserved.

Unfolding large-scale online collaborative human dynamics

PubMed Central

Zha, Yilong; Zhou, Tao; Zhou, Changsong

2016-01-01

Large-scale interacting human activities underlie all social and economic phenomena, but quantitative understanding of regular patterns and mechanism is very challenging and still rare. Self-organized online collaborative activities with a precise record of event timing provide unprecedented opportunity. Our empirical analysis of the history of millions of updates in Wikipedia shows a universal double–power-law distribution of time intervals between consecutive updates of an article. We then propose a generic model to unfold collaborative human activities into three modules: (i) individual behavior characterized by Poissonian initiation of an action, (ii) human interaction captured by a cascading response to previous actions with a power-law waiting time, and (iii) population growth due to the increasing number of interacting individuals. This unfolding allows us to obtain an analytical formula that is fully supported by the universal patterns in empirical data. Our modeling approaches reveal “simplicity” beyond complex interacting human activities. PMID:27911766

The limitations of opportunistic epidemiology, pseudopod epidemiology.

PubMed

Kuller, Lewis H

2016-10-01

Epidemiology has been remarkably successful in the past in identifying the important agents of disease, the impact of the environment, both physical and social, and interrelationship with host susceptibility (genomics). Many of the advances in improving the health of individuals and populations have been the result of epidemiology studies that have identified the specific "agents" of disease and application of public health and preventive medicine. In recent years, large longitudinal studies have dominated epidemiology research, especially long incubation period chronic diseases. The initial hypotheses in these studies have been expanded by vertical extension studies using newer technologies to measure independent variables, vertical pseudopods, and additional studies of other diseases, horizontal pseudopods, of the original longitudinal study. Host susceptibility, i.e. genomics, has also become a prominent component of these longitudinal studies. The critical question addressed in this paper is whether these "pseudopod" epidemiology approaches have enhanced public health or generated a large number of studies of little impact.

Glial cell migration in the eye disc.

PubMed

Silies, Marion; Yuva, Yeliz; Engelen, Daniel; Aho, Annukka; Stork, Tobias; Klämbt, Christian

2007-11-28

Any complex nervous system is made out of two major cell types, neurons and glial cells. A hallmark of glial cells is their pronounced ability to migrate. En route to their final destinations, glial cells are generally guided by neuronal signals. Here we show that in the developing visual system of Drosophila glial cell migration is largely controlled by glial-glial interactions and occurs independently of axonal contact. Differentiation into wrapping glia is initiated close to the morphogenetic furrow. Using single cell labeling experiments we identified six distinct glial cell types in the eye disc. The migratory glial population is separated from the wrapping glial cells by the so-called carpet cells, extraordinary large glial cells, each covering a surface area of approximately 10,000 epithelial cells. Subsequent cell ablation experiments demonstrate that the carpet glia regulates glial migration in the eye disc epithelium and suggest a new model underlying glial migration and differentiation in the developing visual system.

The long-term demographic role of community-based family planning in rural Bangladesh.

PubMed

Phillips, J F; Hossain, M B; Arends-Kuenning, M

1996-01-01

Experimental studies demonstrating the effectiveness of nonclinical distribution of contraceptives are typically conducted in settings where contraceptive use is low and unmet need is extensive. Determining the long-term role of active outreach programs after initial demand is met represents an increasingly important policy issue in Asia, where contraceptive prevalence is high and fixed service points are conveniently available. This article examines the long-term rationale for household family planning in Bangladesh-where growing use of contraceptives, rapid fertility decline, and normative change in reproductive preferences are in progress, bringing into question the rationale for large-scale deployment of paid outreach workers. Longitudinal data are analyzed that record outreach encounters and contraceptive use dynamics in a large rural population. Findings demonstrate that outreach has a continuing impact on program effectiveness, even after a decade of household visitation. The policy implications of this finding are reviewed.

Comparison between maximum radial expansion of ultrasound contrast agents and experimental postexcitation signal results.

PubMed

King, Daniel A; O'Brien, William D

2011-01-01

Experimental postexcitation signal data of collapsing Definity microbubbles are compared with the Marmottant theoretical model for large amplitude oscillations of ultrasound contrast agents (UCAs). After taking into account the insonifying pulse characteristics and size distribution of the population of UCAs, a good comparison between simulated results and previously measured experimental data is obtained by determining a threshold maximum radial expansion (Rmax) to indicate the onset of postexcitation. This threshold Rmax is found to range from 3.4 to 8.0 times the initial bubble radius, R0, depending on insonification frequency. These values are well above the typical free bubble inertial cavitation threshold commonly chosen at 2R0. The close agreement between the experiment and models suggests that lipid-shelled UCAs behave as unshelled bubbles during most of a large amplitude cavitation cycle, as proposed in the Marmottant equation.

Tobacco sales and promotion in bars, cafes and nightclubs from large cities around the world.

PubMed

Shahrir, Shahida; Wipfli, Heather; Avila-Tang, Erika; Breysse, Patrick N; Samet, Jonathan M; Navas-Acien, Ana

2011-07-01

Little is known about tobacco promotion activities in low and middle-income countries. Information on tobacco sales, advertisement and promotion in bars, cafes and nightclubs is needed to develop interventions to reduce smoking initiation and relapse, particularly among youths and young adults. To evaluate cigarette sales and tobacco advertisement and promotion in bars, cafes and nightclubs using a volunteer survey approach in large cities throughout the world. Between 2007 and 2009, we administered an interview-based survey to 231 bar/cafe/nightclub owners/managers in 24 large cities in Africa, the Americas, Asia and eastern Europe. Cigarette sales and tobacco advertisement and promotions were found in bars/cafes/nightclubs in most cities. Examples of promotions included cigarette giveaways and event sponsorship. Establishments that allowed smoking were more likely to sell cigarettes compared to smoke-free establishments (OR 8.67, 95% CI 3.25 to 23.1). Larger establishments (maximum occupancy ≥ 100 vs <100 customers) were more likely to have tobacco advertising (OR 4.35, 95% CI 2.04 to 9.24) and to receive promotional items from tobacco companies (OR 3.18, 95% CI 1.41 to 7.17). Cigarette sales and tobacco promotions were common in bars, cafes and nightclubs in the majority of cities. Socialising and hospitality venues must be covered by legislation banning tobacco sales and promotions to limit exposure among populations at high risk of tobacco initiation and relapse from quitting.

KINETyS: constraining spatial variations of the stellar initial mass function in early-type galaxies★

NASA Astrophysics Data System (ADS)

Alton, Padraig D.; Smith, Russell J.; Lucey, John R.

2017-06-01

The heavyweight stellar initial mass function (IMF) observed in the cores of massive early-type galaxies (ETGs) has been linked to formation of their cores in an initial swiftly quenched rapid starburst. However, the outskirts of ETGs are thought to be assembled via the slow accumulation of smaller systems in which the star formation is less extreme; this suggests that the form of the IMF should exhibit a radial trend in ETGs. Here, we report radial stellar population gradients out to the half-light radii of a sample of eight nearby ETGs. Spatially resolved spectroscopy at 0.8-1.35 μm from the Very Large Telescope's K-band Multi-Object Spectrograph instrument was used to measure radial trends in the strengths of a variety of IMF-sensitive absorption features (including some which are previously unexplored). We find weak or no radial variation in some of these which, given a radial IMF trend, ought to vary measurably, e.g. for the Wing-Ford band, we measure a gradient of +0.06 ± 0.04 per decade in radius. Using stellar population models to fit stacked and individual spectra, we infer that the measured radial changes in absorption feature strengths are primarily accounted for by abundance gradients, which are fairly consistent across our sample (e.g. we derive an average [Na/H] gradient of -0.53 ± 0.07). The inferred contribution of dwarf stars to the total light typically corresponds to a bottom-heavy IMF, but we find no evidence for radial IMF variations in the majority of our sample galaxies.

The time-evolution of DCIS size distributions with applications to breast cancer growth and progression.

PubMed

Dowty, James G; Byrnes, Graham B; Gertig, Dorota M

2014-12-01

Ductal carcinoma in situ (DCIS) lesions are non-invasive tumours of the breast that are thought to precede most invasive breast cancers (IBCs). As individual DCIS lesions are initiated, grow and invade (i.e. become IBC), the size distribution of the DCIS lesions present in a given human population will evolve. We derive a differential equation governing this evolution and show, for given assumptions about growth and invasion, that there is a unique distribution which does not vary with time. Further, we show that any initial distribution converges to this stationary distribution exponentially quickly. Therefore, it is reasonable to assume that the stationary distribution governs the size of DCIS lesions in human populations which are relatively stable with respect to the determinants of breast cancer. Based on this assumption and the size data of 110 DCIS lesions detected in a mammographic screening programme between 1993 and 2000, we produce maximum likelihood estimates for certain growth and invasion parameters. Assuming that DCIS size is proportional to a positive power p of the time since tumour initiation, we estimate p to be 0.50 with a 95% confidence interval of (0.35, 0.71). Therefore, we estimate that DCIS lesions follow a square-root growth law and hence that they grow rapidly when small and relatively slowly when large. Our approach and results should be useful for other mathematical studies of cancer, especially those investigating biological mechanisms of invasion. © The Authors 2013. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

Salt Reduction Initiatives around the World - A Systematic Review of Progress towards the Global Target.

PubMed

Trieu, Kathy; Neal, Bruce; Hawkes, Corinna; Dunford, Elizabeth; Campbell, Norm; Rodriguez-Fernandez, Rodrigo; Legetic, Branka; McLaren, Lindsay; Barberio, Amanda; Webster, Jacqui

2015-01-01

To quantify progress with the initiation of salt reduction strategies around the world in the context of the global target to reduce population salt intake by 30% by 2025. A systematic review of the published and grey literature was supplemented by questionnaires sent to country program leaders. Core characteristics of strategies were extracted and categorised according to a pre-defined framework. A total of 75 countries now have a national salt reduction strategy, more than double the number reported in a similar review done in 2010. The majority of programs are multifaceted and include industry engagement to reformulate products (n = 61), establishment of sodium content targets for foods (39), consumer education (71), front-of-pack labelling schemes (31), taxation on high-salt foods (3) and interventions in public institutions (54). Legislative action related to salt reduction such as mandatory targets, front of pack labelling, food procurement policies and taxation have been implemented in 33 countries. 12 countries have reported reductions in population salt intake, 19 reduced salt content in foods and 6 improvements in consumer knowledge, attitudes or behaviours relating to salt. The large and increasing number of countries with salt reduction strategies in place is encouraging although activity remains limited in low- and middle-income regions. The absence of a consistent approach to implementation highlights uncertainty about the elements most important to success. Rigorous evaluation of ongoing programs and initiation of salt reduction programs, particularly in low- and middle- income countries, will be vital to achieving the targeted 30% reduction in salt intake.

Salt Reduction Initiatives around the World – A Systematic Review of Progress towards the Global Target

PubMed Central

Trieu, Kathy; Neal, Bruce; Hawkes, Corinna; Dunford, Elizabeth; Campbell, Norm; Rodriguez-Fernandez, Rodrigo; Legetic, Branka; McLaren, Lindsay; Barberio, Amanda; Webster, Jacqui

2015-01-01

Objective To quantify progress with the initiation of salt reduction strategies around the world in the context of the global target to reduce population salt intake by 30% by 2025. Methods A systematic review of the published and grey literature was supplemented by questionnaires sent to country program leaders. Core characteristics of strategies were extracted and categorised according to a pre-defined framework. Results A total of 75 countries now have a national salt reduction strategy, more than double the number reported in a similar review done in 2010. The majority of programs are multifaceted and include industry engagement to reformulate products (n = 61), establishment of sodium content targets for foods (39), consumer education (71), front-of-pack labelling schemes (31), taxation on high-salt foods (3) and interventions in public institutions (54). Legislative action related to salt reduction such as mandatory targets, front of pack labelling, food procurement policies and taxation have been implemented in 33 countries. 12 countries have reported reductions in population salt intake, 19 reduced salt content in foods and 6 improvements in consumer knowledge, attitudes or behaviours relating to salt. Conclusion The large and increasing number of countries with salt reduction strategies in place is encouraging although activity remains limited in low- and middle-income regions. The absence of a consistent approach to implementation highlights uncertainty about the elements most important to success. Rigorous evaluation of ongoing programs and initiation of salt reduction programs, particularly in low- and middle- income countries, will be vital to achieving the targeted 30% reduction in salt intake. PMID:26201031

Enhancing Psychosis-Spectrum Nosology Through an International Data Sharing Initiative.

PubMed

Docherty, Anna R; Fonseca-Pedrero, Eduardo; Debbané, Martin; Chan, Raymond C K; Linscott, Richard J; Jonas, Katherine G; Cicero, David C; Green, Melissa J; Simms, Leonard J; Mason, Oliver; Watson, David; Ettinger, Ulrich; Waszczuk, Monika; Rapp, Alexander; Grant, Phillip; Kotov, Roman; DeYoung, Colin G; Ruggero, Camilo J; Eaton, Nicolas R; Krueger, Robert F; Patrick, Christopher; Hopwood, Christopher; O'Neill, F Anthony; Zald, David H; Conway, Christopher C; Adkins, Daniel E; Waldman, Irwin D; van Os, Jim; Sullivan, Patrick F; Anderson, John S; Shabalin, Andrey A; Sponheim, Scott R; Taylor, Stephan F; Grazioplene, Rachel G; Bacanu, Silviu A; Bigdeli, Tim B; Haenschel, Corinna; Malaspina, Dolores; Gooding, Diane C; Nicodemus, Kristin; Schultze-Lutter, Frauke; Barrantes-Vidal, Neus; Mohr, Christine; Carpenter, William T; Cohen, Alex S

2018-05-16

The latent structure of schizotypy and psychosis-spectrum symptoms remains poorly understood. Furthermore, molecular genetic substrates are poorly defined, largely due to the substantial resources required to collect rich phenotypic data across diverse populations. Sample sizes of phenotypic studies are often insufficient for advanced structural equation modeling approaches. In the last 50 years, efforts in both psychiatry and psychological science have moved toward (1) a dimensional model of psychopathology (eg, the current Hierarchical Taxonomy of Psychopathology [HiTOP] initiative), (2) an integration of methods and measures across traits and units of analysis (eg, the RDoC initiative), and (3) powerful, impactful study designs maximizing sample size to detect subtle genomic variation relating to complex traits (the Psychiatric Genomics Consortium [PGC]). These movements are important to the future study of the psychosis spectrum, and to resolving heterogeneity with respect to instrument and population. The International Consortium of Schizotypy Research is composed of over 40 laboratories in 12 countries, and to date, members have compiled a body of schizotypy- and psychosis-related phenotype data from more than 30000 individuals. It has become apparent that compiling data into a protected, relational database and crowdsourcing analytic and data science expertise will result in significant enhancement of current research on the structure and biological substrates of the psychosis spectrum. The authors present a data-sharing infrastructure similar to that of the PGC, and a resource-sharing infrastructure similar to that of HiTOP. This report details the rationale and benefits of the phenotypic data collective and presents an open invitation for participation.

Density of large snags and logs in northern Arizona mixed-conifer and ponderosa pine forests

Treesearch

Joseph L. Ganey; Benjamin J. Bird; L. Scott Baggett; Jeffrey S. Jenness

2015-01-01

Large snags and logs provide important biological legacies and resources for native wildlife, yet data on populations of large snags and logs and factors influencing those populations are sparse. We monitored populations of large snags and logs in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona from 1997 through 2012. We modeled density...

Comparative effectiveness of rivaroxaban versus warfarin or dabigatran for the treatment of patients with non-valvular atrial fibrillation.

PubMed

Norby, Faye L; Bengtson, Lindsay G S; Lutsey, Pamela L; Chen, Lin Y; MacLehose, Richard F; Chamberlain, Alanna M; Rapson, Ian; Alonso, Alvaro

2017-09-06

Rivaroxaban is an oral anticoagulant approved in the US for prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). We determined the effectiveness and associated risks of rivaroxaban versus other oral anticoagulants in a large real-world population. We selected NVAF patients initiating oral anticoagulant use in 2010-2014 enrolled in MarketScan databases. Rivaroxaban users were matched with warfarin and dabigatran users by age, sex, enrolment date, anticoagulant initiation date, and high-dimensional propensity score. Study endpoints, including ischemic stroke, intracranial bleeding (ICB), myocardial infarction (MI), and gastrointestinal (GI) bleeding, were identified from inpatient diagnostic codes. Multivariable Cox models were used to assess associations between type of anticoagulant and outcomes. The analysis included 44,340 rivaroxaban users matched to 89,400 warfarin and 16,957 dabigatran users (38% female, mean age 70) with 12 months of mean follow-up. Anticoagulant-naïve rivaroxaban initiators, but not those switching from warfarin, had lower risk of ischemic stroke [hazard ratio (HR) (95% confidence interval (CI)): 0.75 (0.62, 0.91)] and ICB [HR (95%CI): 0.55, (0.39, 0.78)] than warfarin users. In contrast, anticoagulant-experienced rivaroxaban initiators had higher risk of GI bleeding than warfarin users [HR (95%CI): 1.55 (1.32, 1.83)]. Endpoint rates were similar when comparing anticoagulant-naïve rivaroxaban and dabigatran initiators, with the exception of higher GI bleeding risk in rivaroxaban users [HR (95%CI) 1.28 (1.06, 1.54)]. There were no significant differences in the risk of MI among the comparison groups. In this large real-world sample of NVAF patients, effectiveness and risks of rivaroxaban versus warfarin differed by prior anticoagulant status, while effectiveness of rivaroxaban versus dabigatran differed in GI bleeding risk.

The Birth of a Galaxy: Primordial Metal Enrichment and Stellar Populations

NASA Astrophysics Data System (ADS)

Wise, John H.; Turk, Matthew J.; Norman, Michael L.; Abel, Tom

2012-01-01

By definition, Population III stars are metal-free, and their protostellar collapse is driven by molecular hydrogen cooling in the gas phase, leading to large characteristic masses. Population II stars with lower characteristic masses form when the star-forming gas reaches a critical metallicity of 10-6-10-3.5 Z ⊙. We present an adaptive mesh refinement radiation hydrodynamics simulation that follows the transition from Population III to Population II star formation. The maximum spatial resolution of 1 comoving parsec allows for individual molecular clouds to be well resolved and their stellar associations to be studied in detail. We model stellar radiative feedback with adaptive ray tracing. A top-heavy initial mass function for the Population III stars is considered, resulting in a plausible distribution of pair-instability supernovae and associated metal enrichment. We find that the gas fraction recovers from 5% to nearly the cosmic fraction in halos with merger histories rich in halos above 107 M ⊙. A single pair-instability supernova is sufficient to enrich the host halo to a metallicity floor of 10-3 Z ⊙ and to transition to Population II star formation. This provides a natural explanation for the observed floor on damped Lyα systems metallicities reported in the literature, which is of this order. We find that stellar metallicities do not necessarily trace stellar ages, as mergers of halos with established stellar populations can create superpositions of t-Z evolutionary tracks. A bimodal metallicity distribution is created after a starburst occurs when the halo can cool efficiently through atomic line cooling.

Quantitative Investigation of the Role of Intra-/Intercellular Dynamics in Bacterial Quorum Sensing.

PubMed

Leaman, Eric J; Geuther, Brian Q; Behkam, Bahareh

2018-04-20

Bacteria utilize diffusible signals to regulate population density-dependent coordinated gene expression in a process called quorum sensing (QS). While the intracellular regulatory mechanisms of QS are well-understood, the effect of spatiotemporal changes in the population configuration on the sensitivity and robustness of the QS response remains largely unexplored. Using a microfluidic device, we quantitatively characterized the emergent behavior of a population of swimming E. coli bacteria engineered with the lux QS system and a GFP reporter. We show that the QS activation time follows a power law with respect to bacterial population density, but this trend is disrupted significantly by microscale variations in population configuration and genetic circuit noise. We then developed a computational model that integrates population dynamics with genetic circuit dynamics to enable accurate (less than 7% error) quantitation of the bacterial QS activation time. Through modeling and experimental analyses, we show that changes in spatial configuration of swimming bacteria can drastically alter the QS activation time, by up to 22%. The integrative model developed herein also enables examination of the performance robustness of synthetic circuits with respect to growth rate, circuit sensitivity, and the population's initial size and spatial structure. Our framework facilitates quantitative tuning of microbial systems performance through rational engineering of synthetic ribosomal binding sites. We have demonstrated this through modulation of QS activation time over an order of magnitude. Altogether, we conclude that predictive engineering of QS-based bacterial systems requires not only the precise temporal modulation of gene expression (intracellular dynamics) but also accounting for the spatiotemporal changes in population configuration (intercellular dynamics).

Side population purified from hepatocellular carcinoma cells harbors cancer stem cell-like properties.

PubMed

Chiba, Tetsuhiro; Kita, Kaoru; Zheng, Yun-Wen; Yokosuka, Osamu; Saisho, Hiromitsu; Iwama, Atsushi; Nakauchi, Hiromitsu; Taniguchi, Hideki

2006-07-01

Recent advances in stem cell biology enable us to identify cancer stem cells in solid tumors as well as putative stem cells in normal solid organs. In this study, we applied side population (SP) cell analysis and sorting to established hepatocellular carcinoma (HCC) cell lines to detect subpopulations that function as cancer stem cells and to elucidate their roles in tumorigenesis. Among four cell lines analyzed, SP cells were detected in Huh7 (0.25%) and PLC/PRF/5 cells (0.80%), but not in HepG2 and Huh6 cells. SP cells demonstrated high proliferative potential and anti-apoptotic properties compared with those of non-SP cells. Immunocytochemistry examination showed that SP fractions contain a large number of cells presenting characteristics of both hepatocyte and cholangiocyte lineages. Non-obese diabetic/severe combined immunodeficiency (NOD/SCID) xenograft transplant experiments showed that only 1 x 10(3) SP cells were sufficient for tumor formation, whereas an injection of 1 x 10(6) non-SP cells did not initiate tumors. Re-analysis of SP cell-derived tumors showed that SP cells generated both SP and non-SP cells and tumor-initiating potential was maintained only in SP cells in serial transplantation. Microarray analysis discriminated a differential gene expression profile between SP and non-SP cells, and several so-called "stemness genes" were upregulated in SP cells in HCC cells. In conclusion, we propose that a minority population, detected as SP cells in HCC cells, possess extreme tumorigenic potential and provide heterogeneity to the cancer stem cell system characterized by distinct hierarchy.

Correlates and Prevalence of Menthol Cigarette Use Among Adults With Serious Mental Illness

PubMed Central

Young-Wolff, Kelly C.; Hickman, Norval J.; Kim, Romina; Gali, Kathleen

2015-01-01

Introduction: With a focus on protecting vulnerable groups from initiating and continuing tobacco use, the FDA has been considering the regulation of menthol in cigarettes. Using a large sample of adult smokers with serious mental illness (SMI) in the San Francisco Bay Area, we examined demographic and clinical correlates of menthol use, and we compared the prevalence of menthol use among our study participants to that of adult smokers in the general population in California. Methods: Adult smokers with SMI (N = 1,042) were recruited from 7 acute inpatient psychiatric units in the San Francisco Bay Area. Demographic, tobacco, and clinical correlates of menthol use were examined with bivariate and multivariate logistic regression analyses, and prevalence of menthol use was compared within racial/ethnic groups to California population estimates from the 2008–2011 National Survey on Drug Use and Health. Results: A sample majority (57%) reported smoking menthol cigarettes. Multivariate logistic regression analyses indicated that adult smokers with SMI who were younger, who had racial/ethnic minority status, who had fewer perceived interpersonal problems, and who had greater psychotic symptoms also had a significantly greater likelihood of menthol use. Smokers with SMI had a higher prevalence of menthol use relative to the general population in California overall (24%). Conclusions: Individuals with SMI—particularly those who are younger, have racial/ethnic minority status, and have been diagnosed with a psychotic disorder—are vulnerable to menthol cigarette use. FDA regulation of menthol may prevent initiation and may encourage cessation among smokers with SMI. PMID:25190706

[Malnutrition and poverty in Colombia].

PubMed

Rico Velasco, J; Acciarri, G; Fajardo, L F

1982-01-01

A history of colonial exploitation and a development model that concentrates wealth and excludes a large proportion of the population from the development process are the principal determinants of income distribution in Colombia. This work analyzes the extent of malnutrition among the poorest 30% of the Colombian population. The National Plan for Feeding and Nutrition (PAN), an important component of the national development plan, strives to improve the nutritional status of the most vulnerable population groups living in rural areas and marginal urban neighborhoods, with particular emphasis on mothers and children. The program initially was focussed on 11 priority regions where 5 types of interventions were developed: primary health care, environmental sanitation, food production, food distribution, and nutrition education. Because of the good results initially obtained, PAN now covers the entire national territory. A 1977 survey stratified by socioeconomic levels indicated that among the poorest 30% of the population, 67% of the children examined had low weight for age caused by a combination of chronic and acute malnutrition. 12% were considered to have severe and 23% moderate malnutrition. 8% had severe and 17% had moderate problems of height for age. 26% had deficient weight for height. Comparison of the data to normal values published by the World Health Organization clearly demonstrates the pattern of overall malnutrition indicated by weight for age figures. It can be concluded at 33% of children in the poorest 30% of the population are normal, 31% have mild malnutrition, 23% moderate malnutrition, and 12% severe malnutrition. Data on height for age indicated that 43% were normal, 32% had mild chronic malnutrition, 17% had moderate chronic malnutrition, and 8% had severe chronic malnutrition. The prevalence of acute malnutrition in the poor population measured by the ratio of weight to height was less than that of chronic or overall malnutrition. 21% were considered to show mild, 4% moderate, and 1% severe acute malnutrition. Nutritional status was greatly influenced by age, with the lowest rates of malnutrition occurring in children under 1. Mortality among children aged 1-2 years probably was responsible for a decline in malnutrition rates in children over 2. Patterns of malnutrition in children of the poorest 30% of the Colombian population were quite similar in the 11 departments included in the 1977 survey. Comparison with earlier data indicates that the nutritional status of children in the poorest population sector has not improved since the 1960s.

The genome architecture of the Collaborative Cross mouse genetic reference population.

PubMed

2012-02-01

The Collaborative Cross Consortium reports here on the development of a unique genetic resource population. The Collaborative Cross (CC) is a multiparental recombinant inbred panel derived from eight laboratory mouse inbred strains. Breeding of the CC lines was initiated at multiple international sites using mice from The Jackson Laboratory. Currently, this innovative project is breeding independent CC lines at the University of North Carolina (UNC), at Tel Aviv University (TAU), and at Geniad in Western Australia (GND). These institutions aim to make publicly available the completed CC lines and their genotypes and sequence information. We genotyped, and report here, results from 458 extant lines from UNC, TAU, and GND using a custom genotyping array with 7500 SNPs designed to be maximally informative in the CC and used a novel algorithm to infer inherited haplotypes directly from hybridization intensity patterns. We identified lines with breeding errors and cousin lines generated by splitting incipient lines into two or more cousin lines at early generations of inbreeding. We then characterized the genome architecture of 350 genetically independent CC lines. Results showed that founder haplotypes are inherited at the expected frequency, although we also consistently observed highly significant transmission ratio distortion at specific loci across all three populations. On chromosome 2, there is significant overrepresentation of WSB/EiJ alleles, and on chromosome X, there is a large deficit of CC lines with CAST/EiJ alleles. Linkage disequilibrium decays as expected and we saw no evidence of gametic disequilibrium in the CC population as a whole or in random subsets of the population. Gametic equilibrium in the CC population is in marked contrast to the gametic disequilibrium present in a large panel of classical inbred strains. Finally, we discuss access to the CC population and to the associated raw data describing the genetic structure of individual lines. Integration of rich phenotypic and genomic data over time and across a wide variety of fields will be vital to delivering on one of the key attributes of the CC, a common genetic reference platform for identifying causative variants and genetic networks determining traits in mammals.

Perceptual learning in Williams syndrome: looking beyond averages.

PubMed

Gervan, Patricia; Gombos, Ferenc; Kovacs, Ilona

2012-01-01

Williams Syndrome is a genetically determined neurodevelopmental disorder characterized by an uneven cognitive profile and surprisingly large neurobehavioral differences among individuals. Previous studies have already shown different forms of memory deficiencies and learning difficulties in WS. Here we studied the capacity of WS subjects to improve their performance in a basic visual task. We employed a contour integration paradigm that addresses occipital visual function, and analyzed the initial (i.e. baseline) and after-learning performance of WS individuals. Instead of pooling the very inhomogeneous results of WS subjects together, we evaluated individual performance by expressing it in terms of the deviation from the average performance of the group of typically developing subjects of similar age. This approach helped us to reveal information about the possible origins of poor performance of WS subjects in contour integration. Although the majority of WS individuals showed both reduced baseline and reduced learning performance, individual analysis also revealed a dissociation between baseline and learning capacity in several WS subjects. In spite of impaired initial contour integration performance, some WS individuals presented learning capacity comparable to learning in the typically developing population, and vice versa, poor learning was also observed in subjects with high initial performance levels. These data indicate a dissociation between factors determining initial performance and perceptual learning.

Ecological correlates of invasion impact for Burmese pythons in Florida.

PubMed

Reed, Robert N; Willson, John D; Rodda, Gordon H; Dorcas, Michael E

2012-09-01

An invasive population of Burmese pythons (Python molurus bivittatus) is established across several thousand square kilometers of southern Florida and appears to have caused precipitous population declines among several species of native mammals. Why has this giant snake had such great success as an invasive species when many established reptiles have failed to spread? We scored the Burmese python for each of 15 literature-based attributes relative to predefined comparison groups from a diverse range of taxa and provide a review of the natural history and ecology of Burmese pythons relevant to each attribute. We focused on attributes linked to spread and magnitude of impacts rather than establishment success. Our results suggest that attributes related to body size and generalism appeared to be particularly applicable to the Burmese python's success in Florida. The attributes with the highest scores were: high reproductive potential, low vulnerability to predation, large adult body size, large offspring size and high dietary breadth. However, attributes of ectotherms in general and pythons in particular (including predatory mode, energetic efficiency and social interactions) might have also contributed to invasion success. Although establishment risk assessments are an important initial step in prevention of new establishments, evaluating species in terms of their potential for spreading widely and negatively impacting ecosystems might become part of the means by which resource managers prioritize control efforts in environments with large numbers of introduced species. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Accessibility and use of primary healthcare for immigrants living in the Niagara Region.

PubMed

Lum, Irene D; Swartz, Rebecca H; Kwan, Matthew Y W

2016-05-01

Although the challenges of accessing and using primary healthcare for new immigrants to Canada have been fairly well documented, the focus has primarily been on large cities with significant immigrant populations. The experiences of immigrants living in smaller, less diverse urban centres remain largely unknown. The purpose of this study was to examine the lived experiences of immigrants living in a small urban centre with regards to the primary healthcare system. A total of 13 immigrants living in the Greater Niagara Region participated in semi-structured interviews. All interviews were recorded, transcribed, and then coded and analyzed for emergent themes using NVivo. Five factors were found to impact primary care access and use: lack of social contacts, lack of universal healthcare coverage during their initial arrival, language as a barrier, treatment preferences, and geographic distance to primary care. Overall findings suggest that immigrants moving to smaller areas such as the Niagara Region face similar barriers to primary care as those moving into large cities. Some barriers, however, appear to be specific to the context of smaller urban centres, further exacerbated by living in a small city due to a smaller immigrant population, fewer services for immigrants, and less diversity in practicing physicians. More research is required to understand the contextual factors inhibiting primary care access and use among immigrants moving to smaller urban centres, and determine effective strategies to overcome these barriers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conditions for Optimal Growth of Black Hole Seeds

NASA Astrophysics Data System (ADS)

Pacucci, Fabio; Natarajan, Priyamvada; Volonteri, Marta; Cappelluti, Nico; Urry, C. Megan

2017-12-01

Supermassive black holes weighing up to ˜109 M ⊙ are in place by z ˜ 7, when the age of the universe is ≲1 Gyr. This implies a time crunch for their growth, since such high masses cannot be easily reached in standard accretion scenarios. Here, we explore the physical conditions that would lead to optimal growth wherein stable super-Eddington accretion would be permitted. Our analysis suggests that the preponderance of optimal conditions depends on two key parameters: the black hole mass and the host galaxy central gas density. In the high-efficiency region of this parameter space, a continuous stream of gas can accrete onto the black hole from large to small spatial scales, assuming a global isothermal profile for the host galaxy. Using analytical initial mass functions for black hole seeds, we find an enhanced probability of high-efficiency growth for seeds with initial masses ≳104 M ⊙. Our picture suggests that a large population of high-z lower-mass black holes that formed in the low-efficiency region, with low duty cycles and accretion rates, might remain undetectable as quasars, since we predict their bolometric luminosities to be ≲1041 erg s-1. The presence of these sources might be revealed only via gravitational wave detections of their mergers.

Connecting HL Tau to the observed exoplanet sample

NASA Astrophysics Data System (ADS)

Simbulan, Christopher; Tamayo, Daniel; Petrovich, Cristobal; Rein, Hanno; Murray, Norman

2017-08-01

The Atacama Large Millimeter/submilimeter Array (ALMA) recently revealed a set of nearly concentric gaps in the protoplanetary disc surrounding the young star HL Tauri (HL Tau). If these are carved by forming gas giants, this provides the first set of orbital initial conditions for planets as they emerge from their birth discs. Using N-body integrations, we have followed the evolution of the system for 5 Gyr to explore the possible outcomes. We find that HL Tau initial conditions scaled down to the size of typically observed exoplanet orbits naturally produce several populations in the observed exoplanet sample. First, for a plausible range of planetary masses, we can match the observed eccentricity distribution of dynamically excited radial velocity giant planets with eccentricities >0.2. Secondly, we roughly obtain the observed rate of hot Jupiters around FGK stars. Finally, we obtain a large efficiency of planetary ejections of ≈2 per HL Tau-like system, but the small fraction of stars observed to host giant planets makes it hard to match the rate of free-floating planets inferred from microlensing observations. In view of upcoming Gaia results, we also provide predictions for the expected mutual inclination distribution, which is significantly broader than the absolute inclination distributions typically considered by previous studies.

Access to Emissions Distributions and Related Ancillary Data through the ECCAD database

NASA Astrophysics Data System (ADS)

Darras, Sabine; Granier, Claire; Liousse, Catherine; De Graaf, Erica; Enriquez, Edgar; Boulanger, Damien; Brissebrat, Guillaume

2017-04-01

The ECCAD database (Emissions of atmospheric Compounds and Compilation of Ancillary Data) provides a user-friendly access to global and regional surface emissions for a large set of chemical compounds and ancillary data (land use, active fires, burned areas, population,etc). The emissions inventories are time series gridded data at spatial resolution from 1x1 to 0.1x0.1 degrees. ECCAD is the emissions database of the GEIA (Global Emissions InitiAtive) project and a sub-project of the French Atmospheric Data Center AERIS (http://www.aeris-data.fr). ECCAD has currently more than 2200 users originating from more than 80 countries. The project benefits from this large international community of users to expand the number of emission datasets made available. ECCAD provides detailed metadata for each of the datasets and various tools for data visualization, for computing global and regional totals and for interactive spatial and temporal analysis. The data can be downloaded as interoperable NetCDF CF-compliant files, i.e. the data are compatible with many other client interfaces. The presentation will provide information on the datasets available within ECCAD, as well as examples of the analysis work that can be done online through the website: http://eccad.aeris-data.fr.

Access to Emissions Distributions and Related Ancillary Data through the ECCAD database

NASA Astrophysics Data System (ADS)

Darras, Sabine; Enriquez, Edgar; Granier, Claire; Liousse, Catherine; Boulanger, Damien; Fontaine, Alain

2016-04-01

The ECCAD database (Emissions of atmospheric Compounds and Compilation of Ancillary Data) provides a user-friendly access to global and regional surface emissions for a large set of chemical compounds and ancillary data (land use, active fires, burned areas, population,etc). The emissions inventories are time series gridded data at spatial resolution from 1x1 to 0.1x0.1 degrees. ECCAD is the emissions database of the GEIA (Global Emissions InitiAtive) project and a sub-project of the French Atmospheric Data Center AERIS (http://www.aeris-data.fr). ECCAD has currently more than 2200 users originating from more than 80 countries. The project benefits from this large international community of users to expand the number of emission datasets made available. ECCAD provides detailed metadata for each of the datasets and various tools for data visualization, for computing global and regional totals and for interactive spatial and temporal analysis. The data can be downloaded as interoperable NetCDF CF-compliant files, i.e. the data are compatible with many other client interfaces. The presentation will provide information on the datasets available within ECCAD, as well as examples of the analysis work that can be done online through the website: http://eccad.aeris-data.fr.

Genuine participation in participant-centred research initiatives: the rhetoric and the potential reality.

PubMed

Feeney, Oliver; Borry, Pascal; Felzmann, Heike; Galvagni, Lucia; Haukkala, Ari; Loi, Michele; Nordal, Salvör; Rakic, Vojin; Riso, Brígida; Sterckx, Sigrid; Vears, Danya

2018-04-01

The introduction of Web 2.0 technology, along with a population increasingly proficient in Information and Communications Technology (ICT), coupled with the rapid advancements in genetic testing methods, has seen an increase in the presence of participant-centred research initiatives. Such initiatives, aided by the centrality of ICT interconnections, and the ethos they propound seem to further embody the ideal of increasing the participatory nature of research, beyond what might be possible in non-ICT contexts alone. However, the majority of such research seems to actualise a much narrower definition of 'participation'-where it is merely the case that such research initiatives have increased contact with participants through ICT but are otherwise non-participatory in any important normative sense. Furthermore, the rhetoric of participant-centred initiatives tends to inflate this minimalist form of participation into something that it is not, i.e. something genuinely participatory, with greater connections with both the ICT-facilitated political contexts and the largely non-ICT participatory initiatives that have expanded in contemporary health and research contexts. In this paper, we highlight that genuine (ICT-based) 'participation' should enable a reasonable minimum threshold of participatory engagement through, at least, three central participatory elements: educative, sense of being involved and degree of control. While we agree with criticisms that, at present, genuine participation seems more rhetoric than reality, we believe that there is clear potential for a greater ICT-facilitated participatory engagement on all three participatory elements. We outline some practical steps such initiatives could take to further develop these elements and thereby their level of ICT-facilitated participatory engagement.

Initiating Population Education in Baltimore

ERIC Educational Resources Information Center

Cochran, Caroline S.; McCrea, Lester C.

1974-01-01

After identifying the need for population education in Baltimore City Schools, the school system had the problem of initiating such a course. Working with the Planned Parenthood Association of Maryland, the school system sponsored an in-service program for teachers that resulted in the production of materials for all grades. (MA)

The Translation of Health Research in Kinesiology

ERIC Educational Resources Information Center

Ainsworth, Barbara E.

2009-01-01

The translation of health research is a process of transforming scientific discoveries arising from laboratory, clinical, or population studies into clinical or population-based applications to improve health by reducing disease incidence, morbidity, and mortality. Initiated by the National Institutes for Health Roadmap Initiative and the U.S.…

Continuous and Discrete Structured Population Models with Applications to Epidemiology and Marine Mammals

NASA Astrophysics Data System (ADS)

Tang, Tingting

In this dissertation, we develop structured population models to examine how changes in the environmental affect population processes. In Chapter 2, we develop a general continuous time size structured model describing a susceptible-infected (SI) population coupled with the environment. This model applies to problems arising in ecology, epidemiology, and cell biology. The model consists of a system of quasilinear hyperbolic partial differential equations coupled with a system of nonlinear ordinary differential equations that represent the environment. We develop a second-order high resolution finite difference scheme to numerically solve the model. Convergence of this scheme to a weak solution with bounded total variation is proved. We numerically compare the second order high resolution scheme with a first order finite difference scheme. Higher order of convergence and high resolution property are observed in the second order finite difference scheme. In addition, we apply our model to a multi-host wildlife disease problem, questions regarding the impact of the initial population structure and transition rate within each host are numerically explored. In Chapter 3, we use a stage structured matrix model for wildlife population to study the recovery process of the population given an environmental disturbance. We focus on the time it takes for the population to recover to its pre-event level and develop general formulas to calculate the sensitivity or elasticity of the recovery time to changes in the initial population distribution, vital rates and event severity. Our results suggest that the recovery time is independent of the initial population size, but is sensitive to the initial population structure. Moreover, it is more sensitive to the reduction proportion to the vital rates of the population caused by the catastrophe event relative to the duration of impact of the event. We present the potential application of our model to the amphibian population dynamic and the recovery of a certain plant population. In addition, we explore, in details, the application of the model to the sperm whale population in Gulf of Mexico after the Deepwater Horizon oil spill. In Chapter 4, we summarize the results from Chapter 2 and Chapter 3 and explore some further avenues of our research.

Estimating the coverage of mental health programmes: a systematic review.

PubMed

De Silva, Mary J; Lee, Lucy; Fuhr, Daniela C; Rathod, Sujit; Chisholm, Dan; Schellenberg, Joanna; Patel, Vikram

2014-04-01

The large treatment gap for people suffering from mental disorders has led to initiatives to scale up mental health services. In order to track progress, estimates of programme coverage, and changes in coverage over time, are needed. Systematic review of mental health programme evaluations that assess coverage, measured either as the proportion of the target population in contact with services (contact coverage) or as the proportion of the target population who receive appropriate and effective care (effective coverage). We performed a search of electronic databases and grey literature up to March 2013 and contacted experts in the field. Methods to estimate the numerator (service utilization) and the denominator (target population) were reviewed to explore methods which could be used in programme evaluations. We identified 15 735 unique records of which only seven met the inclusion criteria. All studies reported contact coverage. No study explicitly measured effective coverage, but it was possible to estimate this for one study. In six studies the numerator of coverage, service utilization, was estimated using routine clinical information, whereas one study used a national community survey. The methods for estimating the denominator, the population in need of services, were more varied and included national prevalence surveys case registers, and estimates from the literature. Very few coverage estimates are available. Coverage could be estimated at low cost by combining routine programme data with population prevalence estimates from national surveys.

Developing a National Tiger Action Plan for the Union of Myanmar

NASA Astrophysics Data System (ADS)

Lynam, Antony J.; Khaing, Saw Tun; Zaw, Khin Maung

2006-01-01

A century ago, tigers were considered pests in Myanmar. Hunters claimed thousands, yet populations persisted. In the past century, because of habitat loss and prey depletion, coupled with the recent demand for traditional medicines, tiger populations have been reduced to a few hundred individuals. As a first step toward long-term planning for tigers, and to guide efforts to increase protected area coverage, the Myanmar government in 1998 initiated a project to develop a revised National Tiger Action Plan. Extensive surveys confirmed tigers in only 4 of 17 survey locations. Significant populations are thought to persist in the far North and far South of the country, where large, intact forests offer the potential for tiger recovery. With partnerships and collaborations, tiger populations can be protected in the short term (<5 years) by expanding protected areas and corridors, mobilizing enforcement staff to reduce poaching of tigers and prey, and amending existing wildlife legislation in accordance with international laws. Over the long term (5-20 years), recovery of Myanmar’s tiger populations will depend on increasing support from local people, zoning tiger areas to reduce habitat loss and disturbance, and maintaining connectivity of existing national and transboundary forests. This article reviews the development of a new National Tiger Action Plan for the Union of Myanmar and discusses a blueprint for conservation measures aimed at saving tigers from extinction.

Developing a national tiger action plan for The Union of Myanmar.

PubMed

Lynam, Antony J; Khaing, Saw Tun; Zaw, Khin Maung

2006-01-01

A century ago, tigers were considered pests in Myanmar. Hunters claimed thousands, yet populations persisted. In the past century, because of habitat loss and prey depletion, coupled with the recent demand for traditional medicines, tiger populations have been reduced to a few hundred individuals. As a first step toward long-term planning for tigers, and to guide efforts to increase protected area coverage, the Myanmar government in 1998 initiated a project to develop a revised National Tiger Action Plan. Extensive surveys confirmed tigers in only 4 of 17 survey locations. Significant populations are thought to persist in the far North and far South of the country, where large, intact forests offer the potential for tiger recovery. With partnerships and collaborations, tiger populations can be protected in the short term (<5 years) by expanding protected areas and corridors, mobilizing enforcement staff to reduce poaching of tigers and prey, and amending existing wildlife legislation in accordance with international laws. Over the long term (5-20 years), recovery of Myanmar's tiger populations will depend on increasing support from local people, zoning tiger areas to reduce habitat loss and disturbance, and maintaining connectivity of existing national and transboundary forests. This article reviews the development of a new National Tiger Action Plan for the Union of Myanmar and discusses a blueprint for conservation measures aimed at saving tigers from extinction.

Large Eddy Simulation including population dynamics model for polydisperse droplet evolution

NASA Astrophysics Data System (ADS)

Aiyer, Aditya; Yang, Di; Chamecki, Marcelo; Meneveau, Charles

2017-11-01

Previous studies have shown that dispersion patterns of oil droplets in the ocean following a deep sea oil spill depend critically on droplet diameter. Hence predicting the evolution of the droplet size distribution is of critical importance for predicting macroscopic features of dispersion in the ocean. We adopt a population dynamics model of polydisperse droplet distributions for use in LES. We generalize a breakup model from Reynolds averaging approaches to LES in which the breakup is modeled as due to bombardment of droplets by turbulent eddies of various sizes. The breakage rate is expressed as an integral of a collision frequency times a breakage efficiency over all eddy sizes. An empirical fit to the integral is proposed in order to avoid having to recalculate the integral at every LES grid point and time step. The fit is tested by comparison with various stirred tank experiments. As a flow application for LES we consider a jet of bubbles and large droplets injected at the bottom of the tank. The advected velocity and concentration fields of the drops are described using an Eulerian approach. We study the change of the oil droplet distribution due to breakup caused by interaction of turbulence with the oil droplets. This research was made possible by a Grant from the Gulf of Mexico Research Initiative.

[Epidemiology and clinical characteristics of primary congenital glaucoma].

PubMed

Aziz, A; Fakhoury, O; Matonti, F; Pieri, E; Denis, D

2015-12-01

Primary congenital glaucoma (PCG) is a rare and sight threatening condition. Few large epidemiological studies are available in the literature concerning this condition. The purpose of the study was to evaluate the epidemiological and clinical characteristics of children affected by PCG. Children affected by PCG, from 1 day to 3 years old at the time of diagnosis were retrospectively included between 1999 and 2014. The analysis concerned the pregnancy, family history, initial referral, clinical presentation with description of the classic findings in this condition, mean age at first consultation, duration of follow-up and presence of a delay in treatment, defined as a delay of over one month from the appearance of clinical signs until diagnosis. Two groups were defined according to age at appearance of the clinical signs: "early" group prior to 2 months old and "late" group beyond 2 months up until 3 years old. One hundred and forty-one eyes of 71 children were included, with 49.3% girls (n=35 children) and 50.7% boys (n=36 children) for a male:female ratio of 1.02. The "early" group included 50 children i.e. 70.3% of the population; the "late" group 21 children or 29.7% of the population. A first-degree family history of congenital glaucoma existed in 28% of cases (n=19). The average age at first consultation was 13.1 months for the entire population, and the mean duration of follow-up was 56.6 months. Involvement was bilateral in 99.3% of cases (n=70 children) and the most frequent clinical sign was buphthalmos in 64.5% of eyes (n=91 eyes). Treatment was delayed in 35.3% of cases (n=25 children). This study is of particular relevance because it was performed over a long period and on a large population, considering the rare prevalence of the pathology, and has found epidemiological and clinical data comparable with those available in the literature for similar populations. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Leveraging the "living laboratory": on the emergence of the entrepreneurial hospital.

PubMed

French, Martin; Miller, Fiona Alice

2012-08-01

For years, scholars have debated the "commercial ethos" in higher education, and the rise of the entrepreneurial university. But what of the "entrepreneurial hospital"? Largely unnoticed by scholars, this unique organisational form differs from the entrepreneurial university in some significant ways, not least in its capacity to use its innovations, and to count patients-and even patient populations-amongst its human capital. Accordingly, this article provides an initial conceptualisation of the entrepreneurial hospital, along with an exploration of its larger implications. Using twenty-six semi-structured interviews with key-informants (2008-2009), who work in two networked organisations within a single academic health science system in a Canadian province, our analysis identifies distinctive characteristics of an entrepreneurial hospital. Informed by grounded theory, especially situational analysis, we derive from our data an illustration of potentially incommensurate understandings of the entrepreneurial hospital's resources. On one hand, our study participants view patients and patient populations as a resource for research, linking its value to the contribution it can make to improved, more cost-effective care. On the other hand, some also see commercial potential in this resource. In both cases, exploitation is accompanied by perceived obligations to make proper use of patient populations, and to "give back" to the public-at-large, including through the entrepreneurial search for new ways of mobilising the resources of publicly-funded health care. Thus, a key task of the entrepreneurial hospital is to invent and mediate new uses for its care infrastructure and the unique resource constituted by patient populations. By drawing together care and research in new ways, the entrepreneurial hospital promises increased capacity for biomedical innovation. Yet, as it invents and mediates new uses for patient populations and health care infrastructure, the entrepreneurial hospital stands to significantly redefine both systems of care and the bonds of social solidarity. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Study of the Stellar Population in Selected SO Galaxies

NASA Technical Reports Server (NTRS)

Perez, M.; Danks, A.

1997-01-01

The goal of this program was to observe at least two SO galaxies with abnormal colors in the blue and clear optical signatures of dust and gas. The galaxies NGC 2217 and NGC 1808 were observed at least in one of the IUE cameras (1200-200 and 2000-3200 A) during the 13th episode, using the 4 US1 shifts assigned to this program. The galaxy NGC 2217 had been found to be part of a subgroup of SO galaxies with external gas rotating in retrograde motion with respect to the stars. This galaxy is a face-on object with indications of large amount of gas, quite rare for a SO galaxy. We observed this object on three different occasions with IUE at different positions of the large aperture (spacecraft roll angle) with respect to the nuclear region. These exposures allowed us to take full advantage of the spatial resolution of IUE by mapping nuclear and bulge region of this galaxy. We found that the data point to a marginally earlier stellar population toward the central region. The UV light as a whole is dominated by a late-type stellar population of principally G and K stars. The almost face-on view of this galaxy appears optically thick to UV light. It is conceivable that in analogy to out own Galaxy, the stellar populations weakly detected in NGC 2217, are mostly halo and late-type stars in the center with an increasing contribution of dust and early stellar populations (so far undetected) as we move outward along the faint spiral arms. This result is contrary to our initial expectation, since the counterrotating gas does not appear to be enhancing star formation in this galaxy. Even more interesting were the observations of NGC 1808; galaxy which has been classified, with a handful of other objects, both as a starburst and Seyfert galaxy. Attachment: 'The White-Dwarf Companions of 56 Persei and HR 3643.'

The developing cancer stem-cell model: clinical challenges and opportunities.

PubMed

Vermeulen, Louis; de Sousa e Melo, Felipe; Richel, Dick J; Medema, Jan Paul

2012-02-01

During the past decade, a stem-cell-like subset of cancer cells has been identified in many malignancies. These cells, referred to as cancer stem cells (CSCs), are of particular interest because they are believed to be the clonogenic core of the tumour and therefore represent the cell population that drives growth and progression. Many efforts have been made to design therapies that specifically target the CSC population, since this was predicted to be the crucial population to eliminate. However, recent insights have complicated the initial elegant model, by showing a dominant role for the tumour microenvironment in determining CSC characteristics within a malignancy. This is particularly important since dedifferentiation of non-tumorigenic tumour cells towards CSCs can occur, and therefore the CSC population in a neoplasm is expected to vary over time. Moreover, evidence suggests that not all tumours are driven by rare CSCs, but might instead contain a large population of tumorigenic cells. Even though these results suggest that specific targeting of the CSC population might not be a useful therapeutic strategy, research into the hierarchical cellular organisation of malignancies has provided many important new insights in the biology of tumours. In this Personal View, we highlight how the CSC concept is developing and influences our thinking on future treatment for solid tumours, and recommend ways to design clinical trials to assess drugs that target malignant disease in a rational fashion. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Conservation Strategy for the Florida Scrub-Jay on John F. Kennedy Space Center/Merritt Island National Wildlife Refuge: An Initial Scientific Basis for Recovery

NASA Technical Reports Server (NTRS)

Breininger, D. R.; Larson, V. L.; Schaub, R.; Duncan, B. W.; Schmalzer, P. A.; Oddy, D. M.; Smith, R. B.; Adrian, F.; Hill, H., Jr.

1996-01-01

The Florida Scrub-Jay (Aphelocoma coerulescens) is an indicator of ecosystem integrity of Florida scrub, an endangered ecosystem that requires frequent fire. One of the largest populations of this federally threatened species occurs on John F. Kennedy Space Center/Merritt Island National Wildlife Refuge. Population trends were predicted using population modeling and field data on reproduction and survival of Florida Scrub-Jays collected from 1988 - 1995. Analyses of historical photography indicated that habitat suitability has been declining for 30 years. Field data and computer simulations suggested that the population declined by at least 40% and will decline by another 40% in 1 0 years, if habitat management is not greatly intensified. Data and computer simulations suggest that habitat suitability cannot deviate greatly from optimal for the jay population to persist. Landscape trajectories of vegetation structure, responsible for declining habitat suitability, are associated with the disruption of natural fire regimes. Prescribed fire alone can not reverse the trajectories. A recovery strategy was developed, based on studies of Florida Scrub-Jays and scrub vegetation. A reserve design was formulated based on conservation science principles for scrub ecosystems. The strategy emphasizes frequent fire to restore habitat, but includes mechanical tree cutting for severely degraded areas. Pine thinning across large areas can produce rapid increases in habitat quality. Site-specific strategies will need to be developed, monitored, and modified to achieve conditions suitable for population persistence.