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Sample records for mupirocin strengths weaknesses

  1. Mupirocin

    MedlinePlus

    Mupirocin, an antibiotic, is used to treat impetigo as well as other skin infections caused by bacteria. It is not effective against fungal or viral infections.This medication is sometimes prescribed ...

  2. The Hidden Strengths of Weak Theories

    PubMed Central

    Keil, Frank

    2012-01-01

    There has been a strong tradition of assuming that concepts, and their patterns of formation might be best understood in terms of how they are embedded in theory-like sets of beliefs. Although such views of concepts as embedded in theories have been criticized on five distinct grounds, there are reasonable responses to each of these usual objections. There is, however, a newly emerging concern that is much more challenging to address – people’s intuitive theories seem to be remarkably impoverished. In fact, they are so impoverished it is difficult to see how they could provide the necessary structure to explain differences between concepts and how they might form in development. One response to this recent challenge is to abandon all views of concept structure as being related to people’s intuitive theories and see concepts as essentially structure-free atoms. The alternative proposed here argues that our very weak theories might in fact do a great deal of work in explaining how we form concepts and are able to use them to successfully refer. PMID:25309684

  3. Grip Strength Cutpoints for the Identification of Clinically Relevant Weakness

    PubMed Central

    Shardell, Michelle D.; Peters, Katherine W.; McLean, Robert R.; Dam, Thuy-Tien L.; Kenny, Anne M.; Fragala, Maren S.; Harris, Tamara B.; Kiel, Douglas P.; Guralnik, Jack M.; Ferrucci, Luigi; Kritchevsky, Stephen B.; Studenski, Stephanie A.; Vassileva, Maria T.; Cawthon, Peggy M.

    2014-01-01

    Background. Weakness is common and contributes to disability, but no consensus exists regarding a strength cutpoint to identify persons at high risk. This analysis, conducted as part of the Foundation for the National Institutes of Health Sarcopenia Project, sought to identify cutpoints that distinguish weakness associated with mobility impairment, defined as gait speed less than 0.8 m/s. Methods. In pooled cross-sectional data (9,897 men and 10,950 women), Classification and Regression Tree analysis was used to derive cutpoints for grip strength associated with mobility impairment. Results. In men, a grip strength of 26–32 kg was classified as “intermediate” and less than 26 kg as “weak”; 11% of men were intermediate and 5% were weak. Compared with men with normal strength, odds ratios for mobility impairment were 3.63 (95% CI: 3.01–4.38) and 7.62 (95% CI 6.13–9.49), respectively. In women, a grip strength of 16–20 kg was classified as “intermediate” and less than 16 kg as “weak”; 25% of women were intermediate and 18% were weak. Compared with women with normal strength, odds ratios for mobility impairment were 2.44 (95% CI 2.20–2.71) and 4.42 (95% CI 3.94–4.97), respectively. Weakness based on these cutpoints was associated with mobility impairment across subgroups based on age, body mass index, height, and disease status. Notably, in women, grip strength divided by body mass index provided better fit relative to grip strength alone, but fit was not sufficiently improved to merit different measures by gender and use of a more complex measure. Conclusions. Cutpoints for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function. PMID:24737558

  4. School-Based Sexuality Education in Portugal: Strengths and Weaknesses

    ERIC Educational Resources Information Center

    Rocha, Ana Cristina; Leal, Cláudia; Duarte, Cidália

    2016-01-01

    Portugal, like many other countries, faces obstacles regarding school-based sexuality education. This paper explores Portuguese schools' approaches to implementing sexuality education at a local level, and provides a critical analysis of potential strengths and weaknesses. Documents related to sexuality education in a convenience sample of 89…

  5. Patterns of Strengths and Weaknesses in Children's Knowledge about Fractions

    ERIC Educational Resources Information Center

    Hecht, Steven A.; Vagi, Kevin J.

    2012-01-01

    The purpose of this study was to explore individual patterns of strengths and weaknesses in children's mathematical knowledge about common fractions. Tasks that primarily measure either conceptual or procedural aspects of mathematical knowledge were assessed with the same children in their fourth- and fifth-grade years (N = 181, 56% female and 44%…

  6. [Management models in clinical nutrition: weaknesses and strengths].

    PubMed

    García de Lorenzo, A; Alvarez, J; Burgos, R; Cabrerizo, L; Farrer, K; García Almeida, J M; García Luna, P P; García Peris, P; Llano, J Del; Planas, M; Piñeiro, G

    2009-01-01

    At the 6th Abbott-SENPE Debate Forum a multidisciplinary and multiprofessional discussion was established in order to seek for the model or the models of clinical management most appropriate for Clinical Nutrition and Dietetics Units (CNAD) in Spain. The weaknesses and strengths as well as opportunities for the current systems were assessed concluding that a certain degree of disparity was observed not only due to regional differences but also to different hospital types. It was proposed, from SENPE, the creation of a working group helping to standardize the models and promote the culture of Integral Control and Change Management.

  7. Screening for Mupirocin Resistance in Staphylococcus

    PubMed Central

    Sanju, Avr Jeya; Kopula, Sridharan Sathyamoorthy

    2015-01-01

    Introduction Mupirocin is widely used topical antibiotic for the treatment of skin and soft tissue infections caused by Staphylococcus and Streptococcus. In addition nasal formulations are approved for the use in nasal eradication of methicillin-resistant Staphylococcus aureus in patients and health care workers. Wide usage of mupirocin has resulted in resistance leading to treatment failure. Aim To screen for the mupirocin resistance among the Staphylococcus isolates using disc diffusion and minimum inhibitory concentration method. Materials and Methods A cross-sectional study was done at Microbiology Department of Sri Ramachandra University with 100 strains of Staphylococcus spp isolated from skin and soft tissue infections. Methicillin susceptibility was done by disc diffusion method using oxacillin (1 μgm) and cefoxitin (30 μgm) discs. Isolates were screened for mupirocin resistance by disc diffusion method using 5 μgm discs. High level and low level resistance determined by MIC using agar dilution method. Results In 100 Staphylococcus spp 56 were Staphylococcus aureus and 44 were CoNS. Among the 56 Staphylococcus aureus 49 (87.5%) were mupirocin susceptible and 7 (12.5%) resistant by 5μg disc diffusion method. However by MIC method 11 (19.6%) were high and low level mupirocin resistant. Out of 44 CoNS 22 (50%) and 18 (41%) were susceptible by disc diffusion and MIC method respectively. Of the 26 resistant CoNS low level and high level mupirocin resistant was observed in 7 (15.9%) and 19 (43.1%) respectively. Conclusion Screening for mupirocin resistance by disc diffusion method is important before attempting decolonisation. Mupirocin resistance is more with CoNS. Disc diffusion method may miss low level Mupirocin resistance. PMID:26557517

  8. Big Data and Health Economics: Strengths, Weaknesses, Opportunities and Threats.

    PubMed

    Collins, Brendan

    2016-02-01

    'Big data' is the collective name for the increasing capacity of information systems to collect and store large volumes of data, which are often unstructured and time stamped, and to analyse these data by using regression and other statistical techniques. This is a review of the potential applications of big data and health economics, using a SWOT (strengths, weaknesses, opportunities, threats) approach. In health economics, large pseudonymized databases, such as the planned care.data programme in the UK, have the potential to increase understanding of how drugs work in the real world, taking into account adherence, co-morbidities, interactions and side effects. This 'real-world evidence' has applications in individualized medicine. More routine and larger-scale cost and outcomes data collection will make health economic analyses more disease specific and population specific but may require new skill sets. There is potential for biomonitoring and lifestyle data to inform health economic analyses and public health policy.

  9. Antimicrobial potency of single and combined mupirocin and monoterpenes, thymol, menthol and 1,8-cineole against Staphylococcus aureus planktonic and biofilm growth.

    PubMed

    Kifer, Domagoj; Mužinić, Vedran; Klarić, Maja Šegvić

    2016-09-01

    Staphylococcus aureus is one of the most commonly isolated microbes in chronic rhinosinusitis (CRS) that can be complicated due to the formation of a staphylococcal biofilm. In this study, we investigated antimicrobial efficacy of single mupirocin and three types of monoterpenes (thymol, menthol and 1,8-cineole) as well as mupirocin-monoterpene combinations against S. aureus ATCC 29213 and 5 methicilin-resistant S. aureus strains (MRSA) grown in planktonic and biofilm form. MIC against planktonic bacteria as well as minimum biofilm-eliminating concentrations (MBECs) and minimum biofilm inhibitory concentrations (MBICs) were determined by TTC and MTT reduction assay, respectively. The MICs of mupirocin (0.125-0.156 μg ml(-1)) were three orders of magnitude lower than the MICs of monoterpenes, which were as follows: thymol (0.250-0.375 mg ml(-1)) > menthol (1 mg ml(-1)) > 1,8-cineole (4-8 mg ml(-1)). Mupirocin-monoterpene combinations showed indifferent effect as compared with MICs of single substances. Mupirocin (0.016-2 mg ml(-1)) failed to destroy the biofilm. The MBECs of thymol and menthol were two- to sixfold higher than their MICs, while 1,8-cineole exerted a weak antibiofilm effect with MBECs 16- to 64-fold higher than MICs. Mixture of mupirocin and 1,8 cineole exerted a potentiated biofilm-eliminating effect, mupirocin-menthol showed antagonism, while effect of thymol-mupirocin mixture was inconclusive. MBICs of antimicrobials were close to their MICs, except 1,8-cineole, MBIC was about three- to fivefold higher. Dominant synergy was observed for mixtures of mupirocin and menthol or thymol, whereas mupirocin-1,8-cineol exerted an indifferent or additive biofilm inhibitory effect. Particular combinations of mupirocin and the monoterpenes could be applied in CRS therapy in order to eliminate or prevent bacterial biofilm growth. PMID:26883392

  10. Environmental metabolomics: a SWOT analysis (strengths, weaknesses, opportunities, and threats).

    PubMed

    Miller, Marion G

    2007-02-01

    Metabolomic approaches have the potential to make an exceptional contribution to understanding how chemicals and other environmental stressors can affect both human and environmental health. However, the application of metabolomics to environmental exposures, although getting underway, has not yet been extensively explored. This review will use a SWOT analysis model to discuss some of the strengths, weaknesses, opportunities, and threats that are apparent to an investigator venturing into this relatively new field. SWOT has been used extensively in business settings to uncover new outlooks and identify problems that would impede progress. The field of environmental metabolomics provides great opportunities for discovery, and this is recognized by a high level of interest in potential applications. However, understanding the biological consequence of environmental exposures can be confounded by inter- and intra-individual differences. Metabolomic profiles can yield a plethora of data, the interpretation of which is complex and still being evaluated and researched. The development of the field will depend on the availability of technologies for data handling and that permit ready access metabolomic databases. Understanding the relevance of metabolomic endpoints to organism health vs adaptation vs variation is an important step in understanding what constitutes a substantive environmental threat. Metabolomic applications in reproductive research are discussed. Overall, the development of a comprehensive mechanistic-based interpretation of metabolomic changes offers the possibility of providing information that will significantly contribute to the protection of human health and the environment. PMID:17269710

  11. Environmental metabolomics: a SWOT analysis (strengths, weaknesses, opportunities, and threats).

    PubMed

    Miller, Marion G

    2007-02-01

    Metabolomic approaches have the potential to make an exceptional contribution to understanding how chemicals and other environmental stressors can affect both human and environmental health. However, the application of metabolomics to environmental exposures, although getting underway, has not yet been extensively explored. This review will use a SWOT analysis model to discuss some of the strengths, weaknesses, opportunities, and threats that are apparent to an investigator venturing into this relatively new field. SWOT has been used extensively in business settings to uncover new outlooks and identify problems that would impede progress. The field of environmental metabolomics provides great opportunities for discovery, and this is recognized by a high level of interest in potential applications. However, understanding the biological consequence of environmental exposures can be confounded by inter- and intra-individual differences. Metabolomic profiles can yield a plethora of data, the interpretation of which is complex and still being evaluated and researched. The development of the field will depend on the availability of technologies for data handling and that permit ready access metabolomic databases. Understanding the relevance of metabolomic endpoints to organism health vs adaptation vs variation is an important step in understanding what constitutes a substantive environmental threat. Metabolomic applications in reproductive research are discussed. Overall, the development of a comprehensive mechanistic-based interpretation of metabolomic changes offers the possibility of providing information that will significantly contribute to the protection of human health and the environment.

  12. Committee Effectiveness in Higher Education: The Strengths and Weaknesses of Group Decision Making

    ERIC Educational Resources Information Center

    Bates, Stephen B.

    2014-01-01

    Focusing on five models of committee effectiveness for purposes of this assessment will lend insight into the strengths and weaknesses of utilizing a structured action plan as a guide to achieving and maintaining optimum committee effectiveness in higher education. In the compilation of the strengths and weaknesses of committee decision making,…

  13. Strengths and Weaknesses of NESTs and NNESTs: Perceptions of NNESTs in Hong Kong

    ERIC Educational Resources Information Center

    Ma, Lai Ping Florence

    2012-01-01

    Since non-native English speaking teachers (NNESTs) are always compared with native English speaking teachers (NESTs) on linguistic grounds, their strengths and weaknesses as English teachers are worthy of investigation. This paper reports on a mixed methods study which examines the strengths and weaknesses of NNESTs and NESTs through the…

  14. 75 FR 79295 - New Animal Drugs; Mupirocin

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-20

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Parts 510 and 524 New Animal Drugs; Mupirocin AGENCY...) is amending the animal drug regulations to reflect approval of an abbreviated new animal drug...., has not been previously listed in the animal drug regulations as a sponsor of an approved...

  15. 21 CFR 524.1465 - Mupirocin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1465 Mupirocin. (a... Staphylococcus aureus and S. intermedius. (3) Limitations. Federal law restricts this drug to use by or on...

  16. Judges Cite Current Trends, Comment on Strengths and Weaknesses.

    ERIC Educational Resources Information Center

    Smith, Helen F.

    1995-01-01

    Features opinions of newspaper and yearbook judges as to the state of student publications. Cites as strengths: graphic devices, more pull-out quotes, more double-page spreads with dominant elements, and overall improvement in the quality of magazines. Cites as trends: overdoing opinion at the expense of research, and too many stories that are…

  17. [Archaeology and criminology--Strengths and weaknesses of interdisciplinary cooperation].

    PubMed

    Bachhiesl, Christian

    2015-01-01

    Interdisciplinary cooperation of archaeology and criminology is often focussed on the scientific methods applied in both fields of knowledge. In combination with the humanistic methods traditionally used in archaeology, the finding of facts can be enormously increased and the subsequent hermeneutic deduction of human behaviour in the past can take place on a more solid basis. Thus, interdisciplinary cooperation offers direct and indirect advantages. But it can also cause epistemological problems, if the weaknesses and limits of one method are to be corrected by applying methods used in other disciplines. This may result in the application of methods unsuitable for the problem to be investigated so that, in a way, the methodological and epistemological weaknesses of two disciplines potentiate each other. An example of this effect is the quantification of qualia. These epistemological reflections are compared with the interdisciplinary approach using the concrete case of the "Eulau Crime Scene".

  18. Antimicrobial properties of Pseudomonas strains producing the antibiotic mupirocin.

    PubMed

    Matthijs, Sandra; Vander Wauven, Corinne; Cornu, Bertrand; Ye, Lumeng; Cornelis, Pierre; Thomas, Christopher M; Ongena, Marc

    2014-10-01

    Mupirocin is a polyketide antibiotic with broad antibacterial activity. It was isolated and characterized about 40 years ago from Pseudomonas fluorescens NCIMB 10586. To study the phylogenetic distribution of mupirocin producing strains in the genus Pseudomonas a large collection of Pseudomonas strains of worldwide origin, consisting of 117 Pseudomonas type strains and 461 strains isolated from different biological origins, was screened by PCR for the mmpD gene of the mupirocin gene cluster. Five mmpD(+) strains from different geographic and biological origin were identified. They all produced mupirocin and were strongly antagonistic against Staphylococcus aureus. Phylogenetic analysis showed that mupirocin production is limited to a single species. Inactivation of mupirocin production leads to complete loss of in vitro antagonism against S. aureus, except on certain iron-reduced media where the siderophore pyoverdine is responsible for the in vitro antagonism of a mupirocin-negative mutant. In addition to mupirocin some of the strains produced lipopeptides of the massetolide group. These lipopeptides do not play a role in the observed in vitro antagonism of the mupirocin producing strains against S. aureus. PMID:25303834

  19. Objective Evaluation of Muscle Strength in Infants with Hypotonia and Muscle Weakness

    ERIC Educational Resources Information Center

    Reus, Linda; van Vlimmeren, Leo A.; Staal, J. Bart; Janssen, Anjo J. W. M.; Otten, Barto J.; Pelzer, Ben J.; Nijhuis-van der Sanden, Maria W. G.

    2013-01-01

    The clinical evaluation of an infant with motor delay, muscle weakness, and/or hypotonia would improve considerably if muscle strength could be measured objectively and normal reference values were available. The authors developed a method to measure muscle strength in infants and tested 81 typically developing infants, 6-36 months of age, and 17…

  20. Health Education in India: A Strengths, Weaknesses, Opportunities, and Threats (SWOT) Analysis

    ERIC Educational Resources Information Center

    Sharma, Manoj

    2005-01-01

    The purpose of this study was to conduct a strengths, weaknesses, opportunities, and threats (SWOT) analysis of the health education profession and discipline in India. Materials from CINAHL, ERIC, MEDLINE, and Internet were collected to conduct the open coding of the SWOT analysis. Strengths of health education in India include an elaborate…

  1. The strength-of-weak-ties perspective on creativity: a comprehensive examination and extension.

    PubMed

    Baer, Markus

    2010-05-01

    Disentangling the effects of weak ties on creativity, the present study separated, both theoretically and empirically, the effects of the size and strength of actors' idea networks and examined their joint impact while simultaneously considering the separate, moderating role of network diversity. I hypothesized that idea networks of optimal size and weak strength were more likely to boost creativity when they afforded actors access to a wide range of different social circles. In addition, I examined whether the joint effects of network size, strength, and diversity on creativity were further qualified by the openness to experience personality dimension. As expected, results indicated that actors were most creative when they maintained idea networks of optimal size, weak strength, and high diversity and when they scored high on the openness dimension. The implications of these results are discussed.

  2. Internationally Adopted Children in the Early School Years: Relative Strengths and Weaknesses in Language Abilities

    ERIC Educational Resources Information Center

    Glennen, Sharon

    2015-01-01

    Purpose: This study aimed to determine the relative strengths and weaknesses in language and verbal short-term memory abilities of school-age children who were adopted from Eastern Europe. Method: Children adopted between 1;0 and 4;11 (years;months) of age were assessed with the Clinical Evaluation of Language Fundamentals-Preschool, Second…

  3. Patterns of Cognitive Strengths and Weaknesses: Identification Rates, Agreement, and Validity for Learning Disabilities Identification

    ERIC Educational Resources Information Center

    Miciak, Jeremy; Fletcher, Jack M.; Stuebing, Karla K.; Vaughn, Sharon; Tolar, Tammy D.

    2014-01-01

    Few empirical investigations have evaluated learning disabilities (LD) identification methods based on a pattern of cognitive strengths and weaknesses (PSW). This study investigated the reliability and validity of two proposed PSW methods: the concordance/discordance method (C/DM) and cross battery assessment (XBA) method. Cognitive assessment…

  4. Memory Profiles in Children with Mild Intellectual Disabilities: Strengths and Weaknesses

    ERIC Educational Resources Information Center

    Van der Molen, Mariet J.; Van Luit, Johannes E. H.; Jongmans, Marian J.; Van der Molen, Maurits W.

    2009-01-01

    Strengths and weaknesses in short-term memory (STM) and working memory (WM) were identified in children with mild intellectual disabilities (MID) by comparing their performance to typically developing children matched on chronological age (CA children) and to younger typically developing children with similar mental capacities (MA children).…

  5. Identifying Profiles of Reading Strengths and Weaknesses at the Secondary Level

    ERIC Educational Resources Information Center

    Trentman, Allison M. McCarthy

    2012-01-01

    The purpose of this study was to evaluate the feasibility and potential utility of reading profiles to identify common patterns of reading strengths and weaknesses among students in high school with deficit reading skills. A total of 55 students from three Midwestern high schools were administered a battery of assessments that targeted specific…

  6. The strength of weak connections in the macaque cortico-cortical network.

    PubMed

    Goulas, Alexandros; Schaefer, Alexander; Margulies, Daniel S

    2015-09-01

    Examination of the cortico-cortical network of mammals has unraveled key topological features and their role in the function of the healthy and diseased brain. Recent findings from social and biological networks pinpoint the significant role of weak connections in network coherence and mediation of information from segregated parts of the network. In the current study, inspired by such findings and proposed architectures pertaining to social networks, we examine the structure of weak connections in the macaque cortico-cortical network by employing a tract-tracing dataset. We demonstrate that the cortico-cortical connections as a whole, as well as connections between segregated communities of brain areas, comply with the architecture suggested by the so-called strength-of-weak-ties hypothesis. However, we find that the wiring of these connections is not optimal with respect to the aforementioned architecture. This configuration is not attributable to a trade-off with factors known to constrain brain wiring, i.e., wiring cost and efficiency. Lastly, weak connections, but not strong ones, appear important for network cohesion. Our findings relate a topological property to the strength of cortico-cortical connections, highlight the prominent role of weak connections in the cortico-cortical structural network and pinpoint their potential functional significance. These findings suggest that certain neuroimaging studies, despite methodological challenges, should explicitly take them into account and not treat them as negligible. PMID:25035063

  7. Extraction of Weak Transition Strengths via the (He3, t) Reaction at 420MeV

    NASA Astrophysics Data System (ADS)

    Zegers, R. G. T.; Adachi, T.; Akimune, H.; Austin, Sam M.; van den Berg, A. M.; Brown, B. A.; Fujita, Y.; Fujiwara, M.; Galès, S.; Guess, C. J.; Harakeh, M. N.; Hashimoto, H.; Hatanaka, K.; Hayami, R.; Hitt, G. W.; Howard, M. E.; Itoh, M.; Kawabata, T.; Kawase, K.; Kinoshita, M.; Matsubara, M.; Nakanishi, K.; Nakayama, S.; Okumura, S.; Ohta, T.; Sakemi, Y.; Shimbara, Y.; Shimizu, Y.; Scholl, C.; Simenel, C.; Tameshige, Y.; Tamii, A.; Uchida, M.; Yamagata, T.; Yosoi, M.

    2007-11-01

    Differential cross sections for transitions of known weak strength were measured with the (He3, t) reaction at 420 MeV on targets of C12, C13, O18, Mg26, Ni58, Ni60, Zr90, Sn118, Sn120, and Pb208. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via β-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

  8. Extraction of weak transition strengths via the (3He, t) reaction at 420 MeV.

    PubMed

    Zegers, R G T; Adachi, T; Akimune, H; Austin, Sam M; van den Berg, A M; Brown, B A; Fujita, Y; Fujiwara, M; Galès, S; Guess, C J; Harakeh, M N; Hashimoto, H; Hatanaka, K; Hayami, R; Hitt, G W; Howard, M E; Itoh, M; Kawabata, T; Kawase, K; Kinoshita, M; Matsubara, M; Nakanishi, K; Nakayama, S; Okumura, S; Ohta, T; Sakemi, Y; Shimbara, Y; Shimizu, Y; Scholl, C; Simenel, C; Tameshige, Y; Tamii, A; Uchida, M; Yamagata, T; Yosoi, M

    2007-11-16

    Differential cross sections for transitions of known weak strength were measured with the (3He, t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn, and 208Pb. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

  9. Does Weak Turbulence Impact PMSEs' Strengths Closer To The Northern Pole?

    NASA Astrophysics Data System (ADS)

    Swarnalingam, N.; Hocking, W. K.; Janches, D.; Nicolls, M. J.

    2015-12-01

    Existing 51.0 MHz VHF radar at Eureka (80N, 86W) in northern Canada is located closer to both the northern magnetic and geomagnetic poles. A recent calibrated study of Polar Mesosphere Summer Echoes (PMSE) using this radar supports the previous results by other radars that the absolute signal strength of PMSE in this region is relatively weak compared with the radar observations located at high latitudes. Although very cold temperature and existence of charged ice particles are the most important ingredient required for PMSE to appear, several other factors could potentially influence the absolute signal strengths of these echoes. One of them is neutral air turbulence. Previous studies indicate that upper mesospheric turbulence's strength decreases with latitudes, especially in the very high latitudes [Becker, 2004; Lubken et. al., 2009]. In this study, we investigate long-term mesospheric turbulence strengths at Eureka and study how they could be associated with the weak PMSE signal strengths compared with other high latitude conditions, where PMSE are strong.

  10. Role of editors and journals in detecting and preventing scientific misconduct: strengths, weaknesses, opportunities, and threats.

    PubMed

    Marusic, Ana; Katavic, Vedran; Marusic, Matko

    2007-09-01

    Scientific journals have a central place in protecting research integrity because published articles are the most visible documentation of research. We used SWOT analysis to audit (S)trengths and (W)eaknesses as internal and (O)pportunities and (T)hreats as external factors affecting journals' responsibility in addressing research integrity issues. Strengths include editorial independence, authority and expertise, power to formulate editorial policies, and responsibility for the integrity of published records. Weaknesses stem from having no mandate for legal action, reluctance to get involved, and lack of training. Opportunities for editors are new technologies for detecting misconduct, policies by editorial organization or national institutions, and greater transparency of published research. Editors face threats from the lack of legal regulation and culture of research integrity in academic communities, lack of support from stakeholders in scientific publishing, and different pressures. Journal editors cannot be the policing force of the scientific community but they should actively ensure the integrity of the scientific record.

  11. Strengths and weaknesses of McNamara's evolutionary psychological model of dreaming.

    PubMed

    Olliges, Sandra

    2010-10-07

    This article includes a brief overview of McNamara's (2004) evolutionary model of dreaming. The strengths and weaknesses of this model are then evaluated in terms of its consonance with measurable neurological and biological properties of dreaming, its fit within the tenets of evolutionary theories of dreams, and its alignment with evolutionary concepts of cooperation and spirituality. McNamara's model focuses primarily on dreaming that occurs during rapid eye movement (REM) sleep; therefore this article also focuses on REM dreaming.

  12. SWOT analysis: strengths, weaknesses, opportunities and threats of the Israeli Smallpox Revaccination Program.

    PubMed

    Huerta, Michael; Balicer, Ran D; Leventhal, Alex

    2003-01-01

    During September 2002, Israel began its current revaccination program against smallpox, targeting previously vaccinated "first responders" among medical and emergency workers. In order to identify the potential strengths and weaknesses of this program and the conditions under which critical decisions were reached, we conducted a SWOT analysis of the current Israeli revaccination program, designed to identify its intrinsic strengths and weaknesses, as well as opportunities for its success and threats against it. SWOT analysis--a practical tool for the study of public health policy decisions and the social and political contexts in which they are reached--revealed clear and substantial strengths and weaknesses of the current smallpox revaccination program, intrinsic to the vaccine itself. A number of threats were identified that may jeopardize the success of the current program, chief among them the appearance of severe complications of vaccination. Our finding of a lack of a generation of knowledge on smallpox vaccination highlights the need for improved physician education and dissipation of misconceptions that are prevalent in the public today. PMID:12592958

  13. SWOT analysis: strengths, weaknesses, opportunities and threats of the Israeli Smallpox Revaccination Program.

    PubMed

    Huerta, Michael; Balicer, Ran D; Leventhal, Alex

    2003-01-01

    During September 2002, Israel began its current revaccination program against smallpox, targeting previously vaccinated "first responders" among medical and emergency workers. In order to identify the potential strengths and weaknesses of this program and the conditions under which critical decisions were reached, we conducted a SWOT analysis of the current Israeli revaccination program, designed to identify its intrinsic strengths and weaknesses, as well as opportunities for its success and threats against it. SWOT analysis--a practical tool for the study of public health policy decisions and the social and political contexts in which they are reached--revealed clear and substantial strengths and weaknesses of the current smallpox revaccination program, intrinsic to the vaccine itself. A number of threats were identified that may jeopardize the success of the current program, chief among them the appearance of severe complications of vaccination. Our finding of a lack of a generation of knowledge on smallpox vaccination highlights the need for improved physician education and dissipation of misconceptions that are prevalent in the public today.

  14. Structure and function of emergency care research networks: strengths, weaknesses, and challenges.

    PubMed

    Papa, Linda; Kuppermann, Nathan; Lamond, Katherine; Barsan, William G; Camargo, Carlos A; Ornato, Joseph P; Stiell, Ian G; Talan, David A

    2009-10-01

    The ability of emergency care research (ECR) to produce meaningful improvements in the outcomes of acutely ill or injured patients depends on the optimal configuration, infrastructure, organization, and support of emergency care research networks (ECRNs). Through the experiences of existing ECRNs, we can learn how to best accomplish this. A meeting was organized in Washington, DC, on May 28, 2008, to discuss the present state and future directions of clinical research networks as they relate to emergency care. Prior to the conference, at the time of online registration, participants responded to a series of preconference questions addressing the relevant issues that would form the basis of the breakout session discussions. During the conference, representatives from a number of existing ECRNs participated in discussions with the attendees and provided a description of their respective networks, infrastructure, and challenges. Breakout sessions provided the opportunity to further discuss the strengths and weaknesses of these networks and patterns of success with respect to their formation, management, funding, best practices, and pitfalls. Discussions centered on identifying characteristics that promote or inhibit successful networks and their interactivity, productivity, and expansion. Here the authors describe the current state of ECRNs and identify the strengths, weaknesses, and potential pitfalls of research networks. The most commonly cited strengths of population- or disease-based research networks identified in the preconference survey were access to larger numbers of patients; involvement of physician experts in the field, contributing to high-level study content; and the collaboration among investigators. The most commonly cited weaknesses were studies with too narrow a focus and restrictive inclusion criteria, a vast organizational structure with a risk of either too much or too little central organization or control, and heterogeneity of institutional

  15. Strength of iron at core pressures and evidence for a weak Earth’s inner core

    SciTech Connect

    Gleason, A. E.; Mao, W. L.

    2013-05-12

    The strength of iron at extreme conditions is crucial information for interpreting geophysical observations of the Earth’s core and understanding how the solid inner core deforms. However, the strength of iron, on which deformation depends, is challenging to measure and accurately predict at high pressure. Here we present shear strength measurements of iron up to pressures experienced in the Earth’s core. Hydrostatic X-ray spectroscopy and non-hydrostatic radial X-ray diffraction measurements of the deviatoric strain in hexagonally close-packed iron uniquely determine its shear strength to pressures above 200 GPa at room temperature. Applying numerical modelling of the rheologic behaviour of iron under pressure, we extrapolate our experimental results to inner-core pressures and temperatures, and find that the bulk shear strength of hexagonally close-packed iron is only ~ 1 GPa at the conditions of the Earth’s centre, 364 GPa and 5,500 K. This suggests that the inner core is rheologically weak, which supports dislocation creep as the dominant creep mechanism influencing deformation.

  16. A Historical Perspective on the Development of the Allan Variances and Their Strengths and Weaknesses.

    PubMed

    Allan, David W; Levine, Judah

    2016-04-01

    Over the past 50 years, variances have been developed for characterizing the instabilities of precision clocks and oscillators. These instabilities are often modeled as nonstationary processes, and the variances have been shown to be well-behaved and to be unbiased, efficient descriptors of these types of processes. This paper presents a historical overview of the development of these variances. The time-domain and frequency-domain formulations are presented and their development is described. The strengths and weaknesses of these characterization metrics are discussed. These variances are also shown to be useful in other applications, such as in telecommunication.

  17. Biotic indices for assessing the status of coastal waters: a review of strengths and weaknesses.

    PubMed

    Martínez-Crego, Begoña; Alcoverro, Teresa; Romero, Javier

    2010-05-01

    Biotic indices have become key assessment tools in most recent national and trans-national policies aimed at improving the quality of coastal waters and the integrity of their associated ecosystems. In this study we analyzed 90 published biotic indices, classified them into four types, and analyzed the strengths and weaknesses of each type in relation to the requirements of these policies. We identified three main type-specific weaknesses. First, the problems of applicability, due to practical and conceptual difficulties, which affect most indices related to ecosystem function. Second, the failure of many indices based on structural attributes of the community (e.g. taxonomic composition) to link deterioration with causative stressors, or to provide an early-detection capacity. Third, the poor relevance to the ecological integrity of indices based on attributes at the sub-individual level (e.g. multi-biomarkers). Additionally, most indices still fail on two further aspects: the broad-scale applicability and the definition of reference conditions. Nowadays, the most promising approach seems to be the aggregation of indices with complementary strengths, and obtained from different biological communities. PMID:20383392

  18. Supplementary WMS-III tables for determining primary subtest strengths and weaknesses.

    PubMed

    Ryan, J J; Arb, J D; Ament, P A

    2000-06-01

    It is common practice to evaluate the age-adjusted subtest scores from the Wechsler intelligence scales to determine strengths and weaknesses within a profile. The Wechsler Memory Scale-III (WMS-III; D. Wechsler, 1997a) represents a significant improvement over its predecessors and, for the first time, provides age-adjusted subtest scores for interpretation, just as the Wechsler intelligence scales have done for 60 years. It is reasonable to assume that examiners will evaluate the WMS-III subtest profiles for strengths and weaknesses. However, the WMS-III Administration and Scoring Manual and the WAIS-III-WMS-III Technical Manual (The Psychological Corporation, 1997) provide no assistance for accomplishing this goal. Data from the WMS-III standardization sample, as described in the WAIS-III-WMS-III Technical Manual, were used to develop tables for determining both confidence levels and infrequency of differences between individual subtest scores and the means of 5 subtest combinations that may be clinically relevant for individual cases.

  19. Communicable Diseases Surveillance System in East Azerbaijan Earthquake: Strengths and Weaknesses

    PubMed Central

    Babaie, Javad; Fatemi, Farin; Ardalan, Ali; Mohammadi, Hamed; Soroush, Mahmood

    2014-01-01

    Background: A Surveillance System was established for 19 diseases/syndromes in order to prevent and control communicable diseases after 2012 East Azerbaijan earthquakes. This study was conducted to investigate the strengths and weaknesses of the established SS. Methods: This study was carried out on an interview-based qualitative study using content analysis in 2012. Data was collected by semi-structured deep interviews and surveillance data. Fifteen interviews were conducted with experts and health system managers who were engaged in implementing the communicable disease surveillance system in the affected areas. The selection of participants was purposeful. Data saturation supported the sample size. The collected data was analyzed using the principles suggested by Strauss and Corbin. Results: Establishment of the disease surveillance system was rapid and inexpensive. It collected the required data fast. It also increased confidence in health authorities that the diseases would be under control in earthquake-stricken regions. Non estimated denominator for calculating the rates (incidence & prevalence), non-participation of the private sector and hospitals, rapid turnover of health staff and unfamiliarity with the definitions of the diseases were the weak points of the established disease SS. Conclusion: During the time when surveillance system was active, no significant outbreak of communicable diseases was reported. However, the surveillance system had some weaknesses. Thus, considering Iran’s susceptibility to various natural hazards, repeated exercises should be conducted in the preparedness phase to decrease the weaknesses. In addition, other types of surveillance system such as web-based or mobile-based systems should be piloted in disaster situations for future. PMID:25685619

  20. The Janus-faced nature of comparative psychology--strength or weakness?

    PubMed

    Burghardt, Gordon M

    2013-07-18

    What is the nature of comparative psychology and how does or should it relate to evolutionary psychology? This is a time of reassessment of both fields and this article reviews the history of comparative psychology and its relationships with evolutionary psychology, ethology, and other approaches to behavior from the perspective of a former editor of the Journal of Comparative Psychology who has spent many decades engaged in research in animal behavior. Special attention is given to a reassessment of comparative psychology that was carried out in 1987. The various tensions and orientations that seem endemic to comparative psychology may, in fact, be both a strength and weakness as comparative psychology and evolutionary approaches to human psychology return to issues prominent in the late 19th Century, when both fields were just becoming established.

  1. Strengths and weaknesses of Problem Based Learning from the professional perspective of registered nurses 1

    PubMed Central

    Cónsul-Giribet, María; Medina-Moya, José Luis

    2014-01-01

    OBJECTIVE: to identify competency strengths and weaknesses as perceived by nursing professionals who graduated with a integrated curriculum and competency-based through Problem Based Learning in small groups. METHOD: an intrinsic case study method was used, which analyzes this innovation through former students (from the first class) with three years of professional experience. The data were collected through a questionnaire and discussion groups. RESULTS: the results show that their competency level is valued in a very satisfactory manner. This level paradoxically contrasts with the lack of theoretical knowledge they perceived at the end of their education, when they started working in clinical practice. CONCLUSIONS: the teaching strategy was key to motivate an in-depth study and arouse the desire to know. In addition, Problem Based Learning favors and reinforces the decision to learn, which is that necessary in the course of professional life. PMID:25493666

  2. The voluntary community health movement in India: a strengths, weaknesses, opportunities, and threats (SWOT) analysis.

    PubMed

    Sharma, M; Bhatia, G

    1996-12-01

    There has been a prolific growth of voluntary organizations in India since independence in 1947. One of the major areas of this growth has been in the field of community health. The purpose of this article is to historically trace the voluntary movement in community health in India, analyze the current status, and predict future trends of voluntary efforts. A review of the literature in the form of a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis was the method of this study. Some of the key trends which emerged as the priority areas for progress and for strengthening voluntary organizations in the future were enhancing linkages between health and development; building upon collective force; greater utilization of participatory training; establishing egalitarian and effectual linkages for decision making at the international level; developing self-reliant community-based models; and the need for attaining holistic empowerment at individual, organizational, and community levels through "duty consciousness" as opposed to merely asking for rights.

  3. Traits-based approaches in bioassessment and ecological risk assessment: strengths, weaknesses, opportunities and threats.

    PubMed

    Van den Brink, Paul J; Alexander, Alexa C; Desrosiers, Mélanie; Goedkoop, Willem; Goethals, Peter L M; Liess, Matthias; Dyer, Scott D

    2011-04-01

    We discuss the application of traits-based bioassessment approaches in retrospective bioassessment as well as in prospective ecological risk assessments in regulatory frameworks. Both approaches address the interaction between species and stressors and their consequences at different levels of biological organization, but the fact that a specific species may be less abundant in a potentially impacted site compared with a reference site is, regrettably, insufficient to provide diagnostic information. Species traits may, however, overcome the problems associated with taxonomy-based bioassessment. Trait-based approaches could provide signals regarding what environmental factors may be responsible for the impairment and, thereby, provide causal insight into the interaction between species and stressors. For development of traits-based (TBA), traits should correspond to specific types of stressors or suites of stressors. In this paper, a strengths, weaknesses, opportunities, and threats (SWOT) analysis of TBA in both applications was used to identify challenges and potentials. This paper is part of a series describing the output of the TERA (Traits-based ecological risk assessment: Realising the potential of ecoinformatics approaches in ecotoxicology) Workshop held between 7 and 11 September, 2009, in Burlington, Ontario, Canada. The recognized strengths were that traits are transferrable across geographies, add mechanistic and diagnostic knowledge, require no new sampling methodology, have an old tradition, and can supplement taxonomic analysis. Weaknesses include autocorrelation, redundancy, and inability to protect biodiversity directly. Automated image analysis, combined with genetic and biotechnology tools and improved data analysis to solve autocorrelation problems were identified as opportunities, whereas low availability of trait data, their transferability, their quantitative interpretation, the risk of developing nonrelevant traits, low quality of historic

  4. The availability of attentional resources modulates the inhibitory strength related to weakly activated priming.

    PubMed

    Wang, Yongchun; Wang, Yonghui; Liu, Peng; Dai, Dongyang; Di, Meilin; Chen, Qiang

    2016-08-01

    The current study investigated the role of attention in inhibitory processes (the inhibitory processes described in the current study refer only to those associated with masked or flanked priming) using a mixed paradigm involving the negative compatibility effect (NCE) and object-based attention. Accumulating evidence suggests that attention can be spread more easily within the same object, which increases the availability of attentional resources, than across different objects. Accordingly, we manipulated distractor location (with primes presented in the same object versus presented in different objects) together with prime/target compatibility (compatible versus incompatible) and prime-distractor stimulus onset asynchrony (SOA, 23 ms vs 70 ms). The aim was to investigate whether inhibitory processes related to weakly activated priming, which have been previously assumed to be automatic, depend on the availability of attentional resources. The results of Experiment 1 showed a significant NCE for the 70-ms SOA when the prime and distractor were presented in the same object (greater attentional resource availability); however, reversed NCEs were obtained for all other conditions. Experiment 2 was designed to disentangle whether the results of Experiment 1 were affected by the prime position, and the results indicated that the prime position did not modulate the NCE in Experiment 1. Together, these results are consistent with the claim that the availability of attentional resources modulates the inhibitory strength related to weakly activated priming. Specifically, if attentional resources are assigned to the distractor when it is presented in the same object as the prime, the strength of the inhibition elicited by the distractor may increase and reverse the activation elicited by the prime, which could lead to a significant NCE. PMID:27198916

  5. Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats.

    PubMed

    Soares, Ruben R G; Azevedo, Ana M; Van Alstine, James M; Aires-Barros, M Raquel

    2015-08-01

    For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes. PMID:26213222

  6. Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats.

    PubMed

    Soares, Ruben R G; Azevedo, Ana M; Van Alstine, James M; Aires-Barros, M Raquel

    2015-08-01

    For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes.

  7. Strengths and weaknesses of in-tube solid-phase microextraction: A scoping review.

    PubMed

    Fernández-Amado, M; Prieto-Blanco, M C; López-Mahía, P; Muniategui-Lorenzo, S; Prada-Rodríguez, D

    2016-02-01

    In-tube solid-phase microextraction (in-tube SPME or IT-SPME) is a sample preparation technique which has demonstrated over time its ability to couple with liquid chromatography (LC), as well as its advantages as a miniaturized technique. However, the in-tube SPME perspectives in the forthcoming years depend on solutions that can be brought to the environmental, industrial, food and biomedical analysis. The purpose of this scoping review is to examine the strengths and weaknesses of this technique during the period 2009 to 2015 in order to identify research gaps that should be addressed in the future, as well as the tendencies that are meant to strengthen the technique. In terms of methodological aspects, this scoping review shows the in-tube SPME strengths in the coupling with LC (LC-mass spectrometry, capillary LC, ultra-high-pressure LC), in the new performances (magnetic IT-SPME and electrochemically controlled in-tube SPME) and in the wide range of development of coatings and capillaries. Concerning the applicability, most in-tube SPME studies (around 80%) carry out environmental and biomedical analyses, a lower number food analyses and few industrial analyses. Some promising studies in proteomics have been performed. The review makes a critical description of parameters used in the optimization of in-tube SPME methods, highlighting the importance of some of them (i.e. type of capillary coatings). Commercial capillaries in environmental analysis and laboratory-prepared capillaries in biomedical analysis have been employed with good results. The most consolidated configuration is in-valve mode, however the cycle mode configuration is frequently chosen for biomedical analysis. This scoping review revealed that some aspects such as the combination of in-tube SPME with other sample treatment techniques for the analysis of solid samples should be developed in depth in the near future.

  8. The global health concept of the German government: strengths, weaknesses, and opportunities.

    PubMed

    Bozorgmehr, Kayvan; Bruchhausen, Walter; Hein, Wolfgang; Knipper, Michael; Korte, Rolf; Razum, Oliver; Tinnemann, Peter

    2014-01-01

    Recognising global health as a rapidly emerging policy field, the German federal government recently released a national concept note for global health politics (July 10, 2013). As the German government could have a significant impact on health globally by making a coherent, evidence-informed, and long-term commitment in this field, we offer an initial appraisal of the strengths, weaknesses, and opportunities for development recognised in this document. We conclude that the national concept is an important first step towards the implementation of a coherent global health policy. However, important gaps were identified in the areas of intellectual property rights and access to medicines. In addition, global health determinants such as trade, economic crises, and liberalisation as well as European Union issues such as the health of migrants, refugees, and asylum seekers are not adequately addressed. Furthermore, little information is provided about the establishment of instruments to ensure an effective inter-ministerial cooperation. Finally, because implementation aspects for the national concept are critical for the success of this initiative, we call upon the newly elected 2013 German government to formulate a global health strategy, which includes a concrete plan of action, a time scale, and measurable goals.

  9. The global health concept of the German government: strengths, weaknesses, and opportunities.

    PubMed

    Bozorgmehr, Kayvan; Bruchhausen, Walter; Hein, Wolfgang; Knipper, Michael; Korte, Rolf; Razum, Oliver; Tinnemann, Peter

    2014-01-01

    Recognising global health as a rapidly emerging policy field, the German federal government recently released a national concept note for global health politics (July 10, 2013). As the German government could have a significant impact on health globally by making a coherent, evidence-informed, and long-term commitment in this field, we offer an initial appraisal of the strengths, weaknesses, and opportunities for development recognised in this document. We conclude that the national concept is an important first step towards the implementation of a coherent global health policy. However, important gaps were identified in the areas of intellectual property rights and access to medicines. In addition, global health determinants such as trade, economic crises, and liberalisation as well as European Union issues such as the health of migrants, refugees, and asylum seekers are not adequately addressed. Furthermore, little information is provided about the establishment of instruments to ensure an effective inter-ministerial cooperation. Finally, because implementation aspects for the national concept are critical for the success of this initiative, we call upon the newly elected 2013 German government to formulate a global health strategy, which includes a concrete plan of action, a time scale, and measurable goals. PMID:24560258

  10. Analysis of the strengths and weaknesses of acid rain electronic data reports

    SciTech Connect

    Schott, J.

    1997-12-31

    Entergy Corporation is a Phase II utility with a fossil generation base composed primarily of natural gas and low sulfur coal. This paper presents an analysis of a large Phase II utility`s continuous emissions monitoring data reported to EPA under Title IV Acid Rain. Electric utilities currently report hourly emissions of NO{sub x}, SO{sub 2}, CO{sub 2}, fuel use, and generation through electronic data reports to EPA. This paper describes strengths and weaknesses of the data reported to EPA as determined through an analysis of 1995 data. Emissions reported by this company under acid rain for SO{sub 2} and NO{sub x} are very different from emissions reported to state agencies for annual emission inventory purposes in past years and will represent a significant break with historic trends. A comparison of emissions has been made of 1995 emissions reported under Electronic Data Reports to the emissions that would have been reported using emission factors and fuel data in past years. In addition, the paper examines the impacts of 40 CFR Part 75 Acid Rain requirements such as missing data substitution and monitor bias adjustments. Measurement system errors including stack flow measurement and false NO{sub x}Lb/MMBtu readings at very low loads are discussed. This paper describes the implications for public policy, compliance, emissions inventories, and business decisions of Part 75 acid rain monitoring and reporting requirements.

  11. Patterns of Cognitive Strengths and Weaknesses: Identification Rates, Agreement, and Validity for Learning Disabilities Identification

    PubMed Central

    Miciak, Jeremy; Fletcher, Jack M.; Stuebing, Karla; Vaughn, Sharon; Tolar, Tammy D.

    2014-01-01

    Purpose Few empirical investigations have evaluated LD identification methods based on a pattern of cognitive strengths and weaknesses (PSW). This study investigated the reliability and validity of two proposed PSW methods: the concordance/discordance method (C/DM) and cross battery assessment (XBA) method. Methods Cognitive assessment data for 139 adolescents demonstrating inadequate response to intervention was utilized to empirically classify participants as meeting or not meeting PSW LD identification criteria using the two approaches, permitting an analysis of: (1) LD identification rates; (2) agreement between methods; and (3) external validity. Results LD identification rates varied between the two methods depending upon the cut point for low achievement, with low agreement for LD identification decisions. Comparisons of groups that met and did not meet LD identification criteria on external academic variables were largely null, raising questions of external validity. Conclusions This study found low agreement and little evidence of validity for LD identification decisions based on PSW methods. An alternative may be to use multiple measures of academic achievement to guide intervention. PMID:24274155

  12. The voluntary community health movement in India: a strengths, weaknesses, opportunities, and threats (SWOT) analysis.

    PubMed

    Sharma, M; Bhatia, G

    1996-12-01

    There has been a prolific growth of voluntary organizations in India since independence in 1947. One of the major areas of this growth has been in the field of community health. The purpose of this article is to historically trace the voluntary movement in community health in India, analyze the current status, and predict future trends of voluntary efforts. A review of the literature in the form of a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis was the method of this study. Some of the key trends which emerged as the priority areas for progress and for strengthening voluntary organizations in the future were enhancing linkages between health and development; building upon collective force; greater utilization of participatory training; establishing egalitarian and effectual linkages for decision making at the international level; developing self-reliant community-based models; and the need for attaining holistic empowerment at individual, organizational, and community levels through "duty consciousness" as opposed to merely asking for rights. PMID:8912121

  13. The global health concept of the German government: strengths, weaknesses, and opportunities

    PubMed Central

    Bozorgmehr, Kayvan; Bruchhausen, Walter; Hein, Wolfgang; Knipper, Michael; Korte, Rolf; Razum, Oliver; Tinnemann, Peter

    2014-01-01

    Recognising global health as a rapidly emerging policy field, the German federal government recently released a national concept note for global health politics (July 10, 2013). As the German government could have a significant impact on health globally by making a coherent, evidence-informed, and long-term commitment in this field, we offer an initial appraisal of the strengths, weaknesses, and opportunities for development recognised in this document. We conclude that the national concept is an important first step towards the implementation of a coherent global health policy. However, important gaps were identified in the areas of intellectual property rights and access to medicines. In addition, global health determinants such as trade, economic crises, and liberalisation as well as European Union issues such as the health of migrants, refugees, and asylum seekers are not adequately addressed. Furthermore, little information is provided about the establishment of instruments to ensure an effective inter-ministerial cooperation. Finally, because implementation aspects for the national concept are critical for the success of this initiative, we call upon the newly elected 2013 German government to formulate a global health strategy, which includes a concrete plan of action, a time scale, and measurable goals. PMID:24560258

  14. The Prevalence, Genotype and Antimicrobial Susceptibility of High- and Low-Level Mupirocin Resistant Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Park, Se Young; Kim, Shin Moo

    2012-01-01

    Background Mupirocin has been used for the treatment of skin infections and eradication of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). The increased use of this antibiotic has been accompanied by outbreaks of MRSA that are resistant to mupirocin. Objective This study aims to determine the prevalence, genotype and antimicrobial susceptibility of mupirocin-resistant MRSA from 4 Korean hospitals. Methods A total 193 MRSA clinical isolates were collected from four university hospitals. Antimicrobial susceptibility tests, including mupirocin, and pulsed-field gel electrophoresis (PFGE) pattern analysis were performed. Results Overall, 27 of the 193 (14.1%) MRSA isolates were resistant to mupirocin. All of the (A) hospital isolates showed high-level (HL) mupirocin resistance and the low-level (LL) mupirocin resistant strains were from three other hospitals. The PFGE patterns of 16 mupirocin-resistant isolates were divided into 5 clusters (1-5), and the nine HL mupirocin-resistant isolates belonged to cluster 1. Both the HL and LL mupirocin-resistant MRSA isolates were susceptible to vancomycin and rifampin, but they were resistant to ciprofloxacin, clindamycin and tetracycline. The erythromycin and fusidic acid resistance rates were different between the HL and LL resistant isolates. Conclusion HL mupirocin-resistant isolates that could transfer this resistance to other bacteria were detected and these isolates were clonally related. The emergence of mupirocin resistant isolates emphasizes the importance of using antibiotics judiciously and carefully monitoring the prevalence of mupirocin resistance. PMID:22363153

  15. Neomycin Sulfate Improves the Antimicrobial Activity of Mupirocin-Based Antibacterial Ointments

    PubMed Central

    Blanchard, Catlyn; Brooks, Lauren; Beckley, Andrew; Colquhoun, Jennifer; Dewhurst, Stephen

    2015-01-01

    In the midst of the current antimicrobial pipeline void, alternative approaches are needed to reduce the incidence of infection and decrease reliance on last-resort antibiotics for the therapeutic intervention of bacterial pathogens. In that regard, mupirocin ointment-based decolonization and wound maintenance practices have proven effective in reducing Staphylococcus aureus transmission and mitigating invasive disease. However, the emergence of mupirocin-resistant strains has compromised the agent's efficacy, necessitating new strategies for the prevention of staphylococcal infections. Herein, we set out to improve the performance of mupirocin-based ointments. A screen of a Food and Drug Administration (FDA)-approved drug library revealed that the antibiotic neomycin sulfate potentiates the antimicrobial activity of mupirocin, whereas other library antibiotics did not. Preliminary mechanism of action studies indicate that neomycin's potentiating activity may be mediated by inhibition of the organism's RNase P function, an enzyme that is believed to participate in the tRNA processing pathway immediately upstream of the primary target of mupirocin. The improved antimicrobial activity of neomycin and mupirocin was maintained in ointment formulations and reduced S. aureus bacterial burden in murine models of nasal colonization and wound site infections. Combination therapy improved upon the effects of either agent alone and was effective in the treatment of contemporary methicillin-susceptible, methicillin-resistant, and high-level mupirocin-resistant S. aureus strains. From these perspectives, combination mupirocin-and-neomycin ointments appear to be superior to that of mupirocin alone and warrant further development. PMID:26596945

  16. Mupirocin resistance: clinical implications and potential alternatives for the eradication of MRSA.

    PubMed

    Poovelikunnel, T; Gethin, G; Humphreys, H

    2015-10-01

    Mupirocin 2% ointment is used either alone or with skin antiseptics as part of a comprehensive MRSA decolonization strategy. Increased mupirocin use predisposes to mupirocin resistance, which is significantly associated with persistent MRSA carriage. Mupirocin resistance as high as 81% has been reported. There is a strong association between previous mupirocin exposure and both low-level and high-level mupirocin resistance. High-level mupirocin resistance (mupA carriage) is also linked to MDR. Among MRSA isolates, the presence of the qacA and/or qacB gene, encoding resistance to chlorhexidine, ranges from 65% to 91%, which, along with mupirocin resistance, is associated with failed decolonization. This is of significant concern for patient care and infection prevention and control strategies as both these agents are used concurrently for decolonization. Increasing bacterial resistance necessitates the discovery or development of new antimicrobial therapies. These include, for example, polyhexanide, lysostaphin, ethanol, omiganan pentahydrochloride, tea tree oil, probiotics, bacteriophages and honey. However, few of these have been evaluated fully or extensively tested in clinical trials and this is required to in part address the implications of mupirocin resistance. PMID:26142407

  17. Validation of the Chinese Strengths and Weaknesses of ADHD-Symptoms and Normal-Behaviors Questionnaire in Hong Kong

    ERIC Educational Resources Information Center

    Lai, Kelly Y. C.; Leung, Patrick W. L.; Luk, Ernest S. L.; Wong, Ann S. Y.; Law, Lawrence S. C.; Ho, Karen K. Y.

    2013-01-01

    Objective: Unlike rating scales that focus on the severity of ADHD symptoms, the Strengths and Weaknesses of ADHD-Symptoms and Normal-Behaviors (SWAN) rating scale is phrased in neutral or positive terms for carers to compare the index child's behaviors with that of their peers. This study explores its psychometric properties when applied to…

  18. Global Analysis of the Staphylococcus aureus Response to Mupirocin

    PubMed Central

    Reiß, Swantje; Pané-Farré, Jan; Fuchs, Stephan; François, Patrice; Liebeke, Manuel; Schrenzel, Jacques; Lindequist, Ulrike; Lalk, Michael; Wolz, Christiane; Hecker, Michael

    2012-01-01

    In the present study, we analyzed the response of S. aureus to mupirocin, the drug of choice for nasal decolonization. Mupirocin selectively inhibits the bacterial isoleucyl-tRNA synthetase (IleRS), leading to the accumulation of uncharged isoleucyl-tRNA and eventually the synthesis of (p)ppGpp. The alarmone (p)ppGpp induces the stringent response, an important global transcriptional and translational control mechanism that allows bacteria to adapt to nutritional deprivation. To identify proteins with an altered synthesis pattern in response to mupirocin treatment, we used the highly sensitive 2-dimensional gel electrophoresis technique in combination with mass spectrometry. The results were complemented by DNA microarray, Northern blot, and metabolome analyses. Whereas expression of genes involved in nucleotide biosynthesis, DNA metabolism, energy metabolism, and translation was significantly downregulated, expression of isoleucyl-tRNA synthetase, the branched-chain amino acid pathway, and genes with functions in oxidative-stress resistance (ahpC and katA) and putative roles in stress protection (the yvyD homologue SACOL0815 and SACOL1759 and SACOL2131) and transport processes was increased. A comparison of the regulated genes to known regulons suggests the involvement of the global regulators CodY and SigB in shaping the response of S. aureus to mupirocin. Of particular interest was the induced transcription of genes encoding virulence-associated regulators (i.e., arlRS, saeRS, sarA, sarR, sarS, and sigB), as well as genes directly involved in the virulence of S. aureus (i.e., fnbA, epiE, epiG, and seb). PMID:22106209

  19. Evaluation of the strengths and weaknesses of community-based education from the viewpoint of students

    PubMed Central

    MOKHTARPOUR, SEDIGHEH; AMINI, MITRA; MOUSAVINEZHAD, HOURI; CHOOBINEH, ALIREZA; NABEIEI, PARISA

    2016-01-01

    Introduction: Responsive medicine is an appropriate training method which trains the graduates who can act effectively in initial and secondary aspects of health issues in the society. Methods: This was a cross-sectional descriptive-analytic study which was done using quantitative method. The target population of this study was all the students of the Nutrition and Health School of Shiraz University of Medical Sciences. The sample was randomly selected in this study and 75 students were selected based on the methodologist’s comments and similar studies and random-number table from a list obtained from the school’s department of education. This questionnaire was a researcher-made one which consisted of 23 questions in 2 sections with 21 closed-ended questions and 2 open-ended questions; 70 questionnaires were completed correctly. The closed-ended questions had 4 aspects (completely agree to completely disagree) answered in 5-point Likert scale type. Its face validity was confirmed by 4 faculty members. The construct validity of the questionnaire was analyzed by factor analysis test and its reliability was assessed by a pilot on 20 students with a Cronbach’s alpha of 0.85. The data were analyzed using descriptive statistical tests (mean, standard deviation, …) and the Pearson coefficient (p<0.001). Results: The results of this study showed that the maximum mean score was 3.58±0.65 which was related to the context of these courses and the minimum mean was 2.66±1.14 which was related to the logbook implementation. The 2 open-ended questions indicated that the most important strengths were the use of logbooks as a guide and determining the minimum training; of the weaknesses was the mismatch between the theoretical education and the practical activities. Also, developing the minimum training that an expert should know and using the common topics related to theoretical education were the most important points mentioned by the respondents. Conclusions: The

  20. The Strength of Weak Identities: Social Structural Sources of Self, Situation and Emotional Experience

    ERIC Educational Resources Information Center

    Smith-Lovin, Lynn

    2007-01-01

    Modern societies are highly differentiated, with relatively uncorrelated socially salient dimensions and a preponderance of weak, unidimensional (as opposed to strong, multiplex) ties. What are the implications of a society with fewer strong ties and more weak ties for the self? What do these changes mean for our emotional experience in everyday…

  1. Analysis of Strengths, Weaknesses, Opportunities, and Threats as a Tool for Translating Evidence into Individualized Medical Strategies (I-SWOT)

    PubMed Central

    von Kodolitsch, Yskert; Bernhardt, Alexander M.; Robinson, Peter N.; Kölbel, Tilo; Reichenspurner, Hermann; Debus, Sebastian; Detter, Christian

    2015-01-01

    Background It is the physicians’ task to translate evidence and guidelines into medical strategies for individual patients. Until today, however, there is no formal tool that is instrumental to perform this translation. Methods We introduce the analysis of strengths (S) and weaknesses (W) related to therapy with opportunities (O) and threats (T) related to individual patients as a tool to establish an individualized (I) medical strategy (I-SWOT). The I-SWOT matrix identifies four fundamental types of strategy. These comprise “SO” maximizing strengths and opportunities, “WT” minimizing weaknesses and threats, “WO” minimizing weaknesses and maximizing opportunities, and “ST” maximizing strengths and minimizing threats. Each distinct type of strategy may be considered for individualized medical strategies. Results We describe four steps of I-SWOT to establish an individualized medical strategy to treat aortic disease. In the first step, we define the goal of therapy and identify all evidence-based therapeutic options. In a second step, we assess strengths and weaknesses of each therapeutic option in a SW matrix form. In a third step, we assess opportunities and threats related to the individual patient, and in a final step, we use the I-SWOT matrix to establish an individualized medical strategy through matching “SW” with “OT”. As an example we present two 30-year-old patients with Marfan syndrome with identical medical history and aortic pathology. As a result of I-SWOT analysis of their individual opportunities and threats, we identified two distinct medical strategies in these patients. Conclusion I-SWOT is a formal but easy to use tool to translate medical evidence into individualized medical strategies. PMID:27069939

  2. While Heisenberg Is Not Looking: The Strength of "Weak Measurements" in Educational Research

    ERIC Educational Resources Information Center

    Geelan, David R.

    2015-01-01

    The concept of "weak measurements" in quantum physics is a way of "cheating" the Uncertainty Principle. Heisenberg stated (and 85 years of experiments have demonstrated) that it is impossible to know both the position and momentum of a particle with arbitrary precision. More precise measurements of one decrease the precision…

  3. Scoring the Strengths and Weaknesses of Underage Drinking Laws in the United States

    PubMed Central

    Fell, James C.; Thomas, Sue; Scherer, Michael; Fisher, Deborah A.; Romano, Eduardo

    2015-01-01

    Several studies have examined the impact of a number of minimum legal drinking age 21 (MLDA-21) laws on underage alcohol consumption and alcohol-related crashes in the United States. These studies have contributed to our understanding of how alcohol control laws affect drinking and driving among those who are under age 21. However, much of the extant literature examining underage drinking laws use a “Law/No law” coding which may obscure the variability inherent in each law. Previous literature has demonstrated that inclusion of law strengths may affect outcomes and overall data fit when compared to “Law/No law” coding. In an effort to assess the relative strength of states’ underage drinking legislation, a coding system was developed in 2006 and applied to 16 MLDA-21 laws. The current article updates the previous endeavor and outlines a detailed strength coding mechanism for the current 20 MLDA-21 laws. PMID:26097775

  4. Registration of weak ULF/ELF oscillations of the surface electric field strength

    NASA Astrophysics Data System (ADS)

    Boldyrev, A. I.; Vyazilov, A. E.; Ivanov, V. N.; Kemaev, R. V.; Korovin, V. Ya.; Melyashinskii, A. V.; Pamukhin, K. V.; Panov, V. N.; Shvyrev, Yu. N.

    2016-07-01

    Measurements of the atmospheric electric field strength made by an electrostatic fluxmeter with a unique threshold sensitivity for such devices (6 × 10-2-10-3 V m-1 Hz-1/2 in the 10-3-25 Hz frequency range) and wide dynamic (120 dB) and spectral (0-25 Hz) ranges, are presented. The device parameters make it possible to observe the electric component of global electromagnetic Schumann resonances and long-period fluctuations in the atmospheric electric field strength.

  5. Effect of solubilizing agents on mupirocin loading into and release from PEGylated nanoliposomes.

    PubMed

    Cern, Ahuva; Nativ-Roth, Einat; Goldblum, Amiram; Barenholz, Yechezkel

    2014-07-01

    Mupirocin was identified by quantitative structure property relationship models as a good candidate for remote liposomal loading. Mupirocin is an antibiotic that is currently restricted to topical administration because of rapid hydrolysis in vivo to its inactive metabolite. Formulating mupirocin in PEGylated nanoliposomes may potentially expand its use to parenteral administration by protecting it from degradation in the circulation and target it (by the enhanced permeability effect) to the infected tissue. Mupirocin is slightly soluble in aqueous medium and its solubility can be increased using solubilizing agents. The effect of the solubilizing agents on mupirocin remote loading was studied when the solubilizing agents were added to the drug loading solution. Propylene glycol was found to increase mupirocin loading, whereas polyethylene glycol 400 showed no effect. Hydroxypropyl-β-cyclodextrin (HPCD) showed a concentration-dependent effect on mupirocin loading; using the optimal HPCD concentration increased loading, but higher concentrations inhibited it. The inclusion of HPCD in the liposome aqueous phase while forming the liposomes resulted in increased drug loading and substantially inhibited drug release in serum.

  6. The expression and interpretation of uncertain forensic science evidence: verbal equivalence, evidence strength, and the weak evidence effect.

    PubMed

    Martire, Kristy A; Kemp, Richard I; Watkins, Ian; Sayle, Malindi A; Newell, Ben R

    2013-06-01

    Standards published by the Association of Forensic Science Providers (2009, Standards for the formulation of evaluative forensic science expert opinion, Science & Justice, Vol. 49, pp. 161-164) encourage forensic scientists to express their conclusions in the form of a likelihood ratio (LR), in which the value of the evidence is conveyed verbally or numerically. In this article, we report two experiments (using undergraduates and Mechanical Turk recruits) designed to investigate how much decision makers change their beliefs when presented with evidence in the form of verbal or numeric LRs. In Experiment 1 (N = 494), participants read a summary of a larceny trial containing inculpatory expert testimony in which evidence strength (low, moderate, high) and presentation method (verbal, numerical) varied. In Experiment 2 (N = 411), participants read the same larceny trial, this time including either exculpatory or inculpatory expert evidence that varied in strength (low, high) and presentation method (verbal, numerical). Both studies found a reasonable degree of correspondence in observed belief change resulting from verbal and numeric formats. However, belief change was considerably smaller than Bayesian calculations would predict. In addition, participants presented with evidence weakly supporting guilt tended to "invert" the evidence, thereby counterintuitively reducing their belief in the guilt of the accused. This "weak evidence effect" was most apparent in the verbal presentation conditions of both experiments, but only when the evidence was inculpatory. These findings raise questions about the interpretability of LRs by jurors and appear to support an expectancy-based account of the weak evidence effect.

  7. A Review of Meta-Analyses in Education: Methodological Strengths and Weaknesses

    ERIC Educational Resources Information Center

    Ahn, Soyeon; Ames, Allison J.; Myers, Nicholas D.

    2012-01-01

    The current review addresses the validity of published meta-analyses in education that determines the credibility and generalizability of study findings using a total of 56 meta-analyses published in education in the 2000s. Our objectives were to evaluate the current meta-analytic practices in education, identify methodological strengths and…

  8. Gifted Students with Spatial Strengths and Sequential Weaknesses: An Overlooked and Underidentified Population

    ERIC Educational Resources Information Center

    Mann, Rebecca L.

    2005-01-01

    Gifted students with spatial strengths are often overlooked and underserved in American schools. These students have remarkable areas of talent but often have verbal learning difficulties that prevent them from being identified for gifted services. This article focuses on definitions of spatial ability, characteristics of these learners, possible…

  9. Identification of chromosomal location of mupA gene, encoding low-level mupirocin resistance in staphylococcal isolates.

    PubMed Central

    Ramsey, M A; Bradley, S F; Kauffman, C A; Morton, T M

    1996-01-01

    Low- and high-level mupirocin resistance have been reported in Staphylococcus aureus. The expression of plasmid-encoded mupA is responsible for high-level mupirocin resistance. Low-level mupirocin-resistant strains do not contain plasmid-encoded mupA, and a chromosomal location for this gene has not previously been reported. We examined high- and low-level mupirocin-resistant S. aureus strains to determine if mupA was present on the chromosome of low-level-resistant isolates. Southern blot analysis of DNA from four mupirocin-resistant strains identified mupA in both high- and low-level mupirocin-resistant strains. Low-level mupirocin-resistant strains contained a copy of mupA on the chromosome, while the high-level mupirocin-resistant isolate contained a copy of the gene on the plasmid. PCR amplification of genomic DNA from each mupirocin-resistant strain resulted in a 1.65-kb fragment, the predicted product from the intragenic mupA primers. This is the first report of a chromosomal location for the mupA gene conferring low-level mupirocin resistance. PMID:9124848

  10. Strength of weak layers in cascading failures on multiplex networks: case of the international trade network.

    PubMed

    Lee, Kyu-Min; Goh, K-I

    2016-01-01

    Many real-world complex systems across natural, social, and economical domains consist of manifold layers to form multiplex networks. The multiple network layers give rise to nonlinear effect for the emergent dynamics of systems. Especially, weak layers that can potentially play significant role in amplifying the vulnerability of multiplex networks might be shadowed in the aggregated single-layer network framework which indiscriminately accumulates all layers. Here we present a simple model of cascading failure on multiplex networks of weight-heterogeneous layers. By simulating the model on the multiplex network of international trades, we found that the multiplex model produces more catastrophic cascading failures which are the result of emergent collective effect of coupling layers, rather than the simple sum thereof. Therefore risks can be systematically underestimated in single-layer network analyses because the impact of weak layers can be overlooked. We anticipate that our simple theoretical study can contribute to further investigation and design of optimal risk-averse real-world complex systems. PMID:27211291

  11. Strength of weak layers in cascading failures on multiplex networks: case of the international trade network

    PubMed Central

    Lee, Kyu-Min; Goh, K.-I.

    2016-01-01

    Many real-world complex systems across natural, social, and economical domains consist of manifold layers to form multiplex networks. The multiple network layers give rise to nonlinear effect for the emergent dynamics of systems. Especially, weak layers that can potentially play significant role in amplifying the vulnerability of multiplex networks might be shadowed in the aggregated single-layer network framework which indiscriminately accumulates all layers. Here we present a simple model of cascading failure on multiplex networks of weight-heterogeneous layers. By simulating the model on the multiplex network of international trades, we found that the multiplex model produces more catastrophic cascading failures which are the result of emergent collective effect of coupling layers, rather than the simple sum thereof. Therefore risks can be systematically underestimated in single-layer network analyses because the impact of weak layers can be overlooked. We anticipate that our simple theoretical study can contribute to further investigation and design of optimal risk-averse real-world complex systems. PMID:27211291

  12. Strength of weak layers in cascading failures on multiplex networks: case of the international trade network

    NASA Astrophysics Data System (ADS)

    Lee, Kyu-Min; Goh, K.-I.

    2016-05-01

    Many real-world complex systems across natural, social, and economical domains consist of manifold layers to form multiplex networks. The multiple network layers give rise to nonlinear effect for the emergent dynamics of systems. Especially, weak layers that can potentially play significant role in amplifying the vulnerability of multiplex networks might be shadowed in the aggregated single-layer network framework which indiscriminately accumulates all layers. Here we present a simple model of cascading failure on multiplex networks of weight-heterogeneous layers. By simulating the model on the multiplex network of international trades, we found that the multiplex model produces more catastrophic cascading failures which are the result of emergent collective effect of coupling layers, rather than the simple sum thereof. Therefore risks can be systematically underestimated in single-layer network analyses because the impact of weak layers can be overlooked. We anticipate that our simple theoretical study can contribute to further investigation and design of optimal risk-averse real-world complex systems.

  13. Strengths, weaknesses, opportunities and threats of the pig health monitoring systems used in England.

    PubMed

    Stärk, K D C; Nevel, A

    2009-10-17

    Several systems are being used in England to record information about the health of pigs. The British Pig Health Scheme (BPHS), the National Animal Disease Information System (NADIS), the Zoonoses Action Plan (ZAP) for Salmonella and the Veterinary Investigation Diagnosis Analysis (VIDA) system have been assessed to make recommendations for their future separate or joint development. The structure, organisation, processes, data quality, dissemination, utilisation and acceptance of each system have been assessed. Information was extracted from documents and websites, and informal interviews were conducted with technical experts and stakeholders. The systems covered a broad range of objectives, used variable approaches and operated at very different scales and budgets. There was a high level of awareness and involvement by the industry. Common weaknesses of the systems were the lack of in-depth quantitative analysis of the data, the lack of assessment of each system's impact, and the unknown level of bias as a result of the voluntary or selective participation in them. PMID:19850852

  14. The Strengths and Weaknesses of Logic Formalisms to Support Mishap Analysis

    NASA Technical Reports Server (NTRS)

    Johnson, C. W.; Holloway, C. M.

    2002-01-01

    The increasing complexity of many safety critical systems poses new problems for mishap analysis. Techniques developed in the sixties and seventies cannot easily scale-up to analyze incidents involving tightly integrated software and hardware components. Similarly, the realization that many failures have systemic causes has widened the scope of many mishap investigations. Organizations, including NASA and the NTSB, have responded by starting research and training initiatives to ensure that their personnel are well equipped to meet these challenges. One strand of research has identified a range of mathematically based techniques that can be used to reason about the causes of complex, adverse events. The proponents of these techniques have argued that they can be used to formally prove that certain events created the necessary and sufficient causes for a mishap to occur. Mathematical proofs can reduce the bias that is often perceived to effect the interpretation of adverse events. Others have opposed the introduction of these techniques by identifying social and political aspects to incident investigation that cannot easily be reconciled with a logic-based approach. Traditional theorem proving mechanisms cannot accurately capture the wealth of inductive, deductive and statistical forms of inference that investigators routinely use in their analysis of adverse events. This paper summarizes some of the benefits that logics provide, describes their weaknesses, and proposes a number of directions for future research.

  15. Control of an outbreak of an epidemic methicillin-resistant Staphylococcus aureus also resistant to mupirocin.

    PubMed

    Irish, D; Eltringham, I; Teall, A; Pickett, H; Farelly, H; Reith, S; Woodford, N; Cookson, B

    1998-05-01

    An epidemic methicillin-resistant Staphlococcus aureus (EMRSA-3) appeared in a District hospital in June 1989 as part of a regional outbreak. The dynamics of the outbreak were complex and involved patient transfer between hospitals and wards. Control measures followed UK guidelines and included the use of nasal mupirocin. During these efforts a mupirocin-resistant MRSA [MuMRSA: mupirocin minimum inhibitor concentration (MIC) > 256 mg/L] emerged, probably in a patient who had been given eight mupirocin courses over nine months. The MuMRSA had a narrower phage-typing pattern than EMRSA-3, but was indistinguishable by pulsed-field gel electrophoresis of SmaI chromosomal restriction enzyme digests and its susceptibility pattern to other antibiotics. The results of in vitro curing and gene probing indicated that mupirocin resistance was encoded on a 48 Md plasmid. MuMRSA spread occurred in 12 patients and 11 staff. The affected patients were nursed on the same ward. The strain was eradicated from patients with oral ciprofloxacin and rifampicin, triclosan skin treatment and nasal fusidic acid and bacitracin cream. The control of the outbreak had significant medical, social and financial implications. Fortunately, there were alternative topical agents to mupirocin, an agent which has played such a key role in MRSA eradication in recent years.

  16. A new medium containing mupirocin, acetic acid, and norfloxacin for the selective cultivation of bifidobacteria.

    PubMed

    Vlková, Eva; Salmonová, Hana; Bunešová, Věra; Geigerová, Martina; Rada, Vojtěch; Musilová, Šárka

    2015-08-01

    Various culture media have been proposed for the isolation and selective enumeration of bifidobacteria. Mupirocin is widely used as a selective factor along with glacial acetic acid. TOS (transgalactosylated oligosaccharides) medium supplemented with mupirocin is recommended by the International Dairy Federation for the detection of bifidobacteria in fermented milk products. Mupirocin media with acetic acid are also reliable for intestinal samples in which bifidobacteria predominate. However, for complex samples containing more diverse microbiota, the selectivity of mupirocin media is limited. Resistance to mupirocin has been demonstrated by many anaerobic bacteria, especially clostridia. The objective was to identify an antibiotic that inhibits the growth of clostridia and allows the growth of bifidobacteria, and to use the identified substance to develop a selective cultivation medium for bifidobacteria. The susceptibility of bifidobacteria and clostridia to 12 antibiotics was tested on agar using the disk diffusion method. Only norfloxacin inhibited the growth of clostridia and did not affect the growth of bifidobacteria. Using both pure cultures and faecal samples from infants, adults, calves, lambs, and piglets, the optimal concentration of norfloxacin in solid cultivation media was determined to be 200 mg/L. Our results showed that solid medium containing norfloxacin (200 mg/L) in combination with mupirocin (100 mg/L) and glacial acetic acid (1 mL/L) is suitable for the enumeration and isolation of bifidobacteria from faecal samples of different origins.

  17. A new medium containing mupirocin, acetic acid, and norfloxacin for the selective cultivation of bifidobacteria.

    PubMed

    Vlková, Eva; Salmonová, Hana; Bunešová, Věra; Geigerová, Martina; Rada, Vojtěch; Musilová, Šárka

    2015-08-01

    Various culture media have been proposed for the isolation and selective enumeration of bifidobacteria. Mupirocin is widely used as a selective factor along with glacial acetic acid. TOS (transgalactosylated oligosaccharides) medium supplemented with mupirocin is recommended by the International Dairy Federation for the detection of bifidobacteria in fermented milk products. Mupirocin media with acetic acid are also reliable for intestinal samples in which bifidobacteria predominate. However, for complex samples containing more diverse microbiota, the selectivity of mupirocin media is limited. Resistance to mupirocin has been demonstrated by many anaerobic bacteria, especially clostridia. The objective was to identify an antibiotic that inhibits the growth of clostridia and allows the growth of bifidobacteria, and to use the identified substance to develop a selective cultivation medium for bifidobacteria. The susceptibility of bifidobacteria and clostridia to 12 antibiotics was tested on agar using the disk diffusion method. Only norfloxacin inhibited the growth of clostridia and did not affect the growth of bifidobacteria. Using both pure cultures and faecal samples from infants, adults, calves, lambs, and piglets, the optimal concentration of norfloxacin in solid cultivation media was determined to be 200 mg/L. Our results showed that solid medium containing norfloxacin (200 mg/L) in combination with mupirocin (100 mg/L) and glacial acetic acid (1 mL/L) is suitable for the enumeration and isolation of bifidobacteria from faecal samples of different origins. PMID:25865525

  18. Lessons from Dwarf8 on the Strengths and Weaknesses of Structured Association Mapping

    PubMed Central

    Larsson, Sara J.; Lipka, Alexander E.; Buckler, Edward S.

    2013-01-01

    The strengths of association mapping lie in its resolution and allelic richness, but spurious associations arising from historical relationships and selection patterns need to be accounted for in statistical analyses. Here we reanalyze one of the first generation structured association mapping studies of the Dwarf8 (d8) locus with flowering time in maize using the full range of new mapping populations, statistical approaches, and haplotype maps. Because this trait was highly correlated with population structure, we found that basic structured association methods overestimate phenotypic effects in the region, while mixed model approaches perform substantially better. Combined with analysis of the maize nested association mapping population (a multi-family crossing design), it is concluded that most, if not all, of the QTL effects at the general location of the d8 locus are from rare extended haplotypes that include other linked QTLs and that d8 is unlikely to be involved in controlling flowering time in maize. Previous independent studies have shown evidence for selection at the d8 locus. Based on the evidence of population bottleneck, selection patterns, and haplotype structure observed in the region, we suggest that multiple traits may be strongly correlated with population structure and that selection on these traits has influenced segregation patterns in the region. Overall, this study provides insight into how modern association and linkage mapping, combined with haplotype analysis, can produce results that are more robust. PMID:23437002

  19. OECI accreditation of the European Institute of Oncology of Milan: strengths and weaknesses.

    PubMed

    Deriu, Pietro L; Basso, Silvia; Mastrilli, Fabrizio; Orecchia, Roberto

    2015-01-01

    The European Institute of Oncology began the process to reach the accreditation promoted by the Organisation of European Cancer Institutes (OECI) in 2012. This accreditation integrates the quality and safety path started in 2001 with accreditation by the Joint Commission International. Despite the presence of diversified accreditations and certifications and the clear need of time, effort, and commitment, the models are complementary. Each model is not to be considered as an end but as a tool for improvement: e.g., mixing accreditation standards led to an improvement in the quality and safety of processes. The present article details the OECI accreditation experience of the European Institute of Oncology, in particular the following strengths of OECI standards: collaboration among several involved parties (patient, volunteer, patient's general practitioner) in the clinical and quality/safety processes; a larger involvement of support personnel (psycho-oncologists, dieticians, physical therapists); and the development of clinical/translational research and innovation in prevention, diagnosis, and treatment to guarantee the best available practice in diagnosis and treatment. The OECI accreditation is specific to oncology and therefore its standards are tailored to a cancer center, both in terms of language used in the standards manual and in terms of patient needs. The OECI accreditation system puts an auditor team with a standards manual in charge of verifying quality and confirms the definition of IEO as a Comprehensive Cancer Center. PMID:27096268

  20. Chlorhexidine and mupirocin susceptibilities in methicillin-resistant Staphylococcus aureus isolates from bacteraemia and nasal colonisation.

    PubMed

    Muñoz-Gallego, Irene; Infiesta, Lucia; Viedma, Esther; Perez-Montarelo, Dafne; Chaves, Fernando

    2016-03-01

    Chlorhexidine and mupirocin have been increasingly used in healthcare facilities to eradicate methicillin-resistant Staphylococcus aureus (MRSA) carriage. The aim of this study was to determine the prevalence and mechanisms of chlorhexidine and mupirocin resistance in MRSA from invasive infections and colonisation. MRSA isolates obtained from blood and nasal samples between 2012 and 2014 were analysed. Susceptibility to mupirocin was determined by disk diffusion and Etest and susceptibility to chlorhexidine by broth microdilution. The presence of mupA and qac (A/B and C) genes was investigated by PCR. Molecular typing was performed in high-level mupirocin-resistant (HLMR) isolates. Mupirocin resistance was identified in 15.6% of blood isolates (10.9% HLMR) and 15.1% of nasal isolates (12.0% HLMR). Presence of the mupA gene was confirmed in all HLMR isolates. For blood isolates, chlorhexidine minimum inhibitory concentrations (MICs) ranged from ≤0.125 to 4mg/L and minimum bactericidal concentrations (MBCs) from ≤0.125 to 8mg/L. In nasal isolates, chlorhexidine MICs and MBCs ranged from ≤0.125 to 2mg/L. The qacA/B gene was detected in 2.2% of MRSA isolates (chlorhexidine MIC range 0.25-2mg/L) and the qacC gene in 8.2% (chlorhexidine MIC range ≤0.125-1mg/L). The prevalence of qacC was 18.9% in HLMR isolates and 3.6% in mupirocin-susceptible isolates (P=0.009). Most of the HLMR isolates (97.1%) belonged to ST125 clone. These results suggest that chlorhexidine has a higher potential to prevent infections caused by MRSA. In contrast, mupirocin treatment should be used cautiously to avoid the spread of HLMR MRSA. PMID:27436397

  1. Weak hydrogen bridges: a systematic theoretical study on the nature and strength of C--H...F--C interactions.

    PubMed

    Hyla-Kryspin, Isabella; Haufe, Günter; Grimme, Stefan

    2004-07-19

    We present a comparative study on the nature and strength of weak hydrogen bonding between the C(sp3)-H, C(sp2)-H, and C(sp)-H donor bonds and F-C(sp3) acceptors. The series of molecules CH3F.CH4 (2 a, 2 b), CH3F.C2H4 (3), CH3F.C2H2 (4), as well as model complexes of experimentally characterized 2-fluoro-2-phenylcyclopropane derivatives, C3H6.C3H5F (5 a, 5 b) and C3H5F.C3H5F (6) were investigated. Comparative studies were also performed for two conformers of the methane dimer (1 a, 1 b). The calculations were carried out in hierarchies of basis sets [SV(d,p), TZV(d,p), aug-TZV(d,p), TZV(2df,2pd), aug-TZV(2df,2pd), QZV(3d2fg,2pd), aug-QZV(3d2fg,2pdf)] by means of ab initio [HF, MP2, QCISD, QCISD(T)] methods and density functional theory (DFT/B3LYP, DFT/PBE). It is shown that well-balanced basis sets of at least TZV(2df,2pd) quality are needed for a proper description of the weakly bonded systems. In the case of 2, 3, 5, and 6, the dispersion interaction is the dominant term of the entire attraction, which is not accounted for at the B3LYP level. Significant electrostatic contributions are observed for 6 and 3. For 4, these forces have a dominating contribution to the hydrogen bonding. The C(sp)--H...F--C(sp(3)) interaction in 4, though weak, exhibits the same characteristics as conventional hydrogen bridges. Despite showing longer H.F/H contacts compared to 1 a, 2 a, and 5 a the bifurcated structures, 1 b, 2 b, 5 b, are characterized by larger dispersion interactions leading to stronger bonding. For the systems with only one H.F contact, the MP2/QZV(3d2fg,2pd) interaction energy increases in the order 2 a (-1.62 kJ mol(-1)), 3 (-2.79 kJ mol(-1)), 5 a (-5.97 kJ mol(-1)), 4 (-7.25 kJ mol(-1)), and 6 (-10.02 kJ mol(-1)). This contradicts the estimated proton donor ability of the C--H bonds (2 a<5 a<3<6<4).

  2. Mupirocin-mucin agar for selective enumeration of Bifidobacterium bifidum.

    PubMed

    Pechar, Radko; Rada, Vojtech; Parafati, Lucia; Musilova, Sarka; Bunesova, Vera; Vlkova, Eva; Killer, Jiri; Mrazek, Jakub; Kmet, Vladimir; Svejstil, Roman

    2014-11-17

    Bifidobacterium bifidum is a bacterial species exclusively found in the human intestinal tract. This species is becoming increasingly popular as a probiotic organism added to lyophilized products. In this study, porcine mucin was used as the sole carbon source for the selective enumeration of B. bifidum in probiotic food additives. Thirty-six bifidobacterial strains were cultivated in broth with mucin. Only 13 strains of B. bifidum utilized the mucin to produce acids. B. bifidum was selectively enumerated in eight probiotic food supplements using agar (MM agar) containing mupirocin (100 mg/L) and mucin (20 g/L) as the sole carbon source. MM agar was fully selective if the B. bifidum species was presented together with Bifidobacterium animalis subsp. lactis, Bifidobacterium breve, and Bifidobacterium longum subsp. longum species and with lactic acid bacteria (lactobacilli, streptococci). Isolated strains of B. bifidum were identified using biochemical, PCR, MALDI-TOF procedures and 16S rRNA gene sequencing. The novel selective medium was also suitable for the isolation of B. bifidum strains from human fecal samples.

  3. Patient experience with mupirocin or povidone-iodine nasal decolonization.

    PubMed

    Maslow, Jed; Hutzler, Lorraine; Cuff, Germaine; Rosenberg, Andrew; Phillips, Michael; Bosco, Joseph

    2014-06-01

    Led by the federal government, the payers of health care are enacting policies designed to base provider reimbursement on the quality of care they render. This study evaluated and compared patient experiences and satisfaction with nasal decolonization with either nasal povidone-iodine (PI) or nasal mupirocin ointment (MO). A total of 1903 patients were randomized to undergo preoperative nasal decolonization with either nasal MO or PI solution. All randomized patients were also given 2% chlorhexidine gluconate topical wipes. Patients were interviewed prior to discharge to assess adverse events and patient experience with their assigned preoperative antiseptic protocol. Of the 1903 randomized patients, 1679 (88.1%) were interviewed prior to discharge. Of patients receiving PI, 3.4% reported an unpleasant or very unpleasant experience, compared with 38.8% of those using nasal MO (P<.0001). Sixty-seven percent of patients using nasal MO believed it to be somewhat or very helpful in reducing surgical site infections, compared with 71% of patients receiving PI (P>.05). Being recruited as an active participant in surgical site infection prevention was a positive experience for 87.2% of MO patients and 86.3% of PI patients (P=.652). Those assigned to receive PI solution preoperatively reported significantly fewer adverse events than the nasal MO group (P<.01). Preoperative nasal decolonization with either nasal PI or MO was considered somewhat or very helpful by more than two-thirds of patients. PMID:24972440

  4. Mupirocin-mucin agar for selective enumeration of Bifidobacterium bifidum.

    PubMed

    Pechar, Radko; Rada, Vojtech; Parafati, Lucia; Musilova, Sarka; Bunesova, Vera; Vlkova, Eva; Killer, Jiri; Mrazek, Jakub; Kmet, Vladimir; Svejstil, Roman

    2014-11-17

    Bifidobacterium bifidum is a bacterial species exclusively found in the human intestinal tract. This species is becoming increasingly popular as a probiotic organism added to lyophilized products. In this study, porcine mucin was used as the sole carbon source for the selective enumeration of B. bifidum in probiotic food additives. Thirty-six bifidobacterial strains were cultivated in broth with mucin. Only 13 strains of B. bifidum utilized the mucin to produce acids. B. bifidum was selectively enumerated in eight probiotic food supplements using agar (MM agar) containing mupirocin (100 mg/L) and mucin (20 g/L) as the sole carbon source. MM agar was fully selective if the B. bifidum species was presented together with Bifidobacterium animalis subsp. lactis, Bifidobacterium breve, and Bifidobacterium longum subsp. longum species and with lactic acid bacteria (lactobacilli, streptococci). Isolated strains of B. bifidum were identified using biochemical, PCR, MALDI-TOF procedures and 16S rRNA gene sequencing. The novel selective medium was also suitable for the isolation of B. bifidum strains from human fecal samples. PMID:25217723

  5. Mupirocin-induced mutations in ileS in various genetic backgrounds of methicillin-resistant Staphylococcus aureus.

    PubMed

    Lee, Andie S; Gizard, Yann; Empel, Joanna; Bonetti, Eve-Julie; Harbarth, Stephan; François, Patrice

    2014-10-01

    Topical mupirocin is widely used for the decolonization of methicillin-resistant Staphylococcus aureus (MRSA) carriers. We evaluated the capacity of various MRSA clonotypes to develop mutations in the ileS gene associated with low-level mupirocin resistance. Twenty-four mupirocin-sensitive MRSA isolates from a variety of genotypes (determined by a multilocus variable-number tandem-repeat assay) were selected. Mupirocin MICs were determined by Etest. The isolates were then incubated in subinhibitory concentrations of mupirocin for 7 to 14 days. Repeat MIC determinations and sequencing of the ileS gene were then performed. Doubling times of isolates exposed to mupirocin and of unexposed isolates were compared. We found that exposure to mupirocin led to rapid induction of low-level resistance (MICs of 8 to 24 μg/ml) in 11 of 24 (46%) MRSA isolates. This phenomenon was observed in strains with diverse genetic backgrounds. Various mutations were detected in 18 of 24 (75%) MRSA isolates. Acquisition of mutations appeared to be a stepwise process during prolonged incubation with the drug. Among the five isolates exhibiting low-level resistance and the highest MICs, four tested sensitive after incubation in the absence of mupirocin but there was no reversion to the susceptible wild-type primary sequence. Resistance was not associated with significant fitness cost, suggesting that MRSA strains with low-level mupirocin resistance may have a selective advantage in facilities where mupirocin is commonly used. Our findings emphasize the importance of the judicious use of this topical agent and the need to closely monitor for the emergence of resistance.

  6. The Effect of Achievement Test Selection on Identification of Learning Disabilities within a Patterns of Strengths and Weaknesses Framework

    PubMed Central

    Miciak, Jeremy; Taylor, Pat; Denton, Carolyn A.; Fletcher, Jack M.

    2014-01-01

    Purpose Few empirical investigations have evaluated learning disabilities (LD) identification methods based on a pattern of cognitive strengths and weaknesses (PSW). This study investigated the reliability of LD classification decisions of the concordance/discordance method (C/DM) across different psychoeducational assessment batteries. Methods C/DM criteria were applied to assessment data from 177 second grade students based on two psychoeducational assessment batteries. The achievement tests were different, but were highly correlated and measured the same latent construct. Resulting LD identifications were then evaluated for agreement across batteries on LD status and the academic domain of eligibility. Results The two batteries identified a similar number of participants as having LD (80 and 74). However, indices of agreement for classification decisions were low (kappa = .29), especially for percent positive agreement (62%). The two batteries demonstrated agreement on the academic domain of eligibility for only 25 participants. Conclusions Cognitive discrepancy frameworks for LD identification are inherently unstable because of imperfect reliability and validity at the observed level. Methods premised on identifying a PSW profile may never achieve high reliability because of these underlying psychometric factors. An alternative is to directly assess academic skills to identify students in need of intervention. PMID:25243467

  7. Use of mupirocin-chlorhexidine treatment to prevent Staphylococcus aureus surgical-site infections.

    PubMed

    Bertrand, X; Slekovec, C; Talon, D

    2010-05-01

    Evaluation of: Bode LGM, Kluytmans JAJW, Wertheim HFL et al.: Preventing surgical-site infections in nasal carriers of Staphylococcus aureus. N. Engl. J. Med. 362, 9-17 (2010). Staphylococcus aureus is the main pathogen responsible for surgical-site infections and nasal carriage is a major risk factor for subsequent infection with this bacteria. Mupirocin is considered to be the topical antibacterial agent of choice for eradication of nasal S. aureus. The paper by Bode et al. provides strong evidence that the combination of a rapid identification of a S. aureus nasal carrier, mupirocin nasal ointment and chlorhexidine gluconate soap, significantly reduces the rate of S. aureus surgical-site infection by nearly 60%. In conclusion, mupirocin nasal ointment use in S. aureus carriers before surgery has numerous advantages with few side effects. PMID:20441543

  8. Impact of mupirocin resistance on the transmission and control of healthcare-associated MRSA

    PubMed Central

    Deeny, Sarah R.; Worby, Colin J.; Tosas Auguet, Olga; Cooper, Ben S.; Edgeworth, Jonathan; Cookson, Barry; Robotham, Julie V.

    2015-01-01

    Objectives The objectives of this study were to estimate the relative transmissibility of mupirocin-resistant (MupR) and mupirocin-susceptible (MupS) MRSA strains and evaluate the long-term impact of MupR on MRSA control policies. Methods Parameters describing MupR and MupS strains were estimated using Markov chain Monte Carlo methods applied to data from two London teaching hospitals. These estimates parameterized a model used to evaluate the long-term impact of MupR on three mupirocin usage policies: ‘clinical cases’, ‘screen and treat’ and ‘universal’. Strategies were assessed in terms of colonized and infected patient days and scenario and sensitivity analyses were performed. Results The transmission probability of a MupS strain was 2.16 (95% CI 1.38–2.94) times that of a MupR strain in the absence of mupirocin usage. The total prevalence of MupR in colonized and infected MRSA patients after 5 years of simulation was 9.1% (95% CI 8.7%–9.6%) with the ‘screen and treat’ mupirocin policy, increasing to 21.3% (95% CI 20.9%–21.7%) with ‘universal’ mupirocin use. The prevalence of MupR increased in 50%–75% of simulations with ‘universal’ usage and >10% of simulations with ‘screen and treat’ usage in scenarios where MupS had a higher transmission probability than MupR. Conclusions Our results provide evidence from a clinical setting of a fitness cost associated with MupR in MRSA strains. This provides a plausible explanation for the low levels of mupirocin resistance seen following ‘screen and treat’ mupirocin usage. From our simulations, even under conservative estimates of relative transmissibility, we see long-term increases in the prevalence of MupR given ‘universal’ use. PMID:26338047

  9. An Examination of the Strengths, Weaknesses, Opportunities, and Threats Associated with the Adoption of Moodle[TM] by eXtension

    ERIC Educational Resources Information Center

    Hightower, Tayla Elise; Murphrey, Theresa Pesl; Coppernoll, Susanna Mumm; Jahedkar, Jennifer; Dooley, Kim E.

    2011-01-01

    The use of technology to deliver programming across Extension has been addressed widely; however, little research has been conducted concerning the use of Moodle[TM] as a course management system for Extension. The purpose of the study reported here was to identify the strengths, weaknesses, opportunities, and threats associated with the use of…

  10. Special Education and Rehabilitation in Georgia: Strengths, Weakness, Opportunities, and Threats in a Newly-Independent State of the Former Soviet Union.

    ERIC Educational Resources Information Center

    Hobbs, Tim; Szydlowski, Steven; West, Daniel, Jr.; Germava, Otar

    2002-01-01

    Forty-nine Georgian professionals from the fields of health, education, and rehabilitation were brought together for a week-long workshop to discuss issues related to disability, rehabilitation, and special education. Workshop activities included a SWOT (strengths, weaknesses, opportunities, and threats) analysis of special education in Georgia.…

  11. A Study of Strengths and Weaknesses of Descriptive Assessment from Principals, Teachers and Experts Points of View in Chaharmahal and Bakhteyari Primary Schools

    ERIC Educational Resources Information Center

    Sharief, Mostafa; Naderi, Mahin; Hiedari, Maryam Shoja; Roodbari, Omolbanin; Jalilvand, Mohammad Reza

    2012-01-01

    The aim of current study is to determine the strengths and weaknesses of descriptive evaluation from the viewpoint of principals, teachers and experts of Chaharmahal and Bakhtiari province. A descriptive survey was performed. Statistical population includes 208 principals, 303 teachers, and 100 executive experts of descriptive evaluation scheme in…

  12. Wildfire Prevention and Suppression plans enhancing: a first overview on strength and weakness in Italian stakeholders experiences and perception.

    NASA Astrophysics Data System (ADS)

    Bonora, Laura; Conese, Claudio; Barbati, Anna

    2014-05-01

    Fires and wildfires represent an element of vulnerability for forests, considering that have now reached a level beyond which further burning would seriously endanger the ecosystem services and their sustainable management. It is fundamental to support fire-fighting Centres by giving them tools, useful to faces future trends; in this sense the first step is to examine technical and operative procedures to evaluate their strong and weak aspects, in collaboration with personnel responsible of risk management, suppression coordination and patrol responsible of direct attack. The aims this work is to identify present elements of strength ad problematic aspects to tuning the wildfire suppression actions to future changes; this is a crucial challenge both for policy and territory planners and managers. Historical investigation lines on forest fire covered the basilar and fundamental dynamics which understanding was necessary to confine and fight the wildfire phenomenon. At the present all the competences, knowledge and connections acquired are translating and including in the Plans, sharing innovative strategies -with the "direct involved actors"- trying to decrease the fire trend. Stakeholders underlined that collaboration between research and territorial Institutions are producing positive results, showing the conceptual rightness and the well-run of the in-progress implementations. The Italian framework of wildfire prevention plans is very peculiar because the Plans related to prevention and active intervention procedure are coincident. Normative, procedural, economic and logistic aspects are considered and handled in the same general document; each year the local structures, designed by the Regions, have in charge the draft of the operative plan, defining and managing the means and patrols distribution and turnover. In the present work 3 Italian Regions (Tuscany, Puglia and Sardinia, with different territorial and vegetation characteristics and affected by different

  13. AERONET-OC: Strengths and Weaknesses of a Network for the Validation of Satellite Coastal Radiometric Products

    NASA Technical Reports Server (NTRS)

    Zibordi, Giuseppe; Holben, Brent; Slutsker, Ilya; Giles, David; D'Alimonte, Davide; Melin, Frederic; Berthon, Jean-Francois; Vandemark, Doug; Feng, Hui; Schuster, Gregory; Fabbri, Bryan E.; Kaitala, Seppo; Seppala, Jukka

    2008-01-01

    The Ocean Color component of the Aerosol Robotic Network (AERONET-OC) has been implemented to support long-term satellite ocean color investigations through cross-site consistent and accurate measurements collected by autonomous radiometer systems deployed on offshore fixed platforms. The ultimate purpose of AERONET-OC is the production of standardized measurements performed at different sites with identical measuring systems and protocols, calibrated using a single reference source and method, and processed with the same code. The AERONET-OC primary data product is the normalized water leaving radiance determined at center-wavelengths of interest for satellite ocean color applications, with an uncertainty lower than 5% in the blue-green spectral regions and higher than 8% in the red. Measurements collected at 6 sites counting the northern Adriatic Sea, the Baltic Proper, the Gulf of Finland, the Persian Gulf, and, the northern and southern margins of the Middle Atlantic Bay, have shown the capability of producing quality assured data over a wide range of bio-optical conditions including Case-2 yellow substance- and sedimentdominated waters. This work briefly introduces network elements like: deployment sites, measurement method, instrument calibration, processing scheme, quality-assurance, uncertainties, data archive and products accessibility. Emphases is given to those elements which underline the network strengths (i.e., mostly standardization of any network element) and its weaknesses (i.e., the use of consolidated, but old-fashioned technology). The work also addresses the application of AERONET-OC data to the validation of primary satellite radiometric products over a variety of complex coastal waters and finally provides elements for the identification of new deployment sites most suitable to support satellite ocean color missions.

  14. Stability of mupirocin ointment (Bactroban) admixed with other proprietary dermatological products.

    PubMed

    Jagota, N K; Stewart, J T; Warren, F W; John, P M

    1992-06-01

    This study involved the mixing of 1:1 combinations of Bactroban (mupirocin) Ointment 2% with various cream, lotion, ointment, gel, solution and liquid soap formulations with storage at 37 degrees C for 60 days. The mixtures were assayed for mupirocin content at 0, 15, 30, 45 and 60 days using a high-pressure liquid chromatographic (HPLC) assay. At the time of preparation of these admixtures, Bactroban Ointment is chemically and physically compatible with all of the topical dermatological products studied except for Valisone lotion where a physical incompatibility is immediately observed. Admixtures of Hibiclens liquid soap or Lotrimin solution with Bactroban Ointment were stable throughout the entire 60-day study. Combinations of Lotrimin cream, Hytone cream, Valisone ointment or Vytone cream with Bactroban Ointment also retained chemical stability of mupirocin for the entire period even though two layers were observed and mixing was required to restore a physically homogenous mixture. Other Bactroban Ointment admixtures were found to be either chemically stable for mupirocin for periods less than 60 days or physically incompatible mixtures were observed upon storage. No conclusions were drawn from these studies concerning the efficacy or safety of any of these products when used in extemporaneously prepared combinations.

  15. Strengths and weaknesses of weak-strong cluster problems: A detailed overview of state-of-the-art classical heuristics versus quantum approaches

    NASA Astrophysics Data System (ADS)

    Mandrà, Salvatore; Zhu, Zheng; Wang, Wenlong; Perdomo-Ortiz, Alejandro; Katzgraber, Helmut G.

    2016-08-01

    To date, a conclusive detection of quantum speedup remains elusive. Recently, a team by Google Inc. [V. S. Denchev et al., Phys. Rev. X 6, 031015 (2016), 10.1103/PhysRevX.6.031015] proposed a weak-strong cluster model tailored to have tall and narrow energy barriers separating local minima, with the aim to highlight the value of finite-range tunneling. More precisely, results from quantum Monte Carlo simulations as well as the D-Wave 2X quantum annealer scale considerably better than state-of-the-art simulated annealing simulations. Moreover, the D-Wave 2X quantum annealer is ˜108 times faster than simulated annealing on conventional computer hardware for problems with approximately 103 variables. Here, an overview of different sequential, nontailored, as well as specialized tailored algorithms on the Google instances is given. We show that the quantum speedup is limited to sequential approaches and study the typical complexity of the benchmark problems using insights from the study of spin glasses.

  16. Correlation of mupirocin resistance with biofilm production in methicillin-resistant Staphylococcus aureus from surgical site infections in a tertiary centre, Egypt.

    PubMed

    Barakat, Ghada I; Nabil, Yasmin M

    2016-03-01

    The aim of this study was to detect mupirocin-resistant isolates from pus/wound swabs taken postoperatively in a tertiary centre in Egypt and to determine their ability to form biofilm in order to establish its correlation with mupirocin resistance. This was a prospective study including 513pus/wound swabs from patients suffering from postoperative surgical site infections over the period July 2013-January 2015. Samples were cultured and isolates were identified by coagulase activity, DNase test, mannitol fermentation by mannitol salt agar followed by API Staph 32. Oxacillin agar screen test, agar dilution test for mupirocin, and mupA gene detection by PCR were performed for all methicillin-resistant Staphylococcus aureus (MRSA) isolates. Biofilm detection was carried out by the microtitre plate and Congo red agar methods. Of the 161 S. aureus isolates identified, 73 (45.3%) were MRSA, among which 82.2% were mupirocin-susceptible and 17.8% were mupirocin-resistant. Among the resistant isolates, 38.5% showed low-level resistance and 61.5% were high-level mupirocin-resistant. The mupA gene was detected in 75.0% of high-level mupirocin-resistant strains and in none of the low-level mupirocin-resistant strains. Among the mupirocin-susceptible isolates, 95.0% were biofilm-producers and 5.0% did not produce biofilm. All mupirocin-resistant isolates produced biofilm. Moreover, 15.3% of high-level mupirocin-resistant strains were negative for the mupA gene but showed evidence of biofilm formation. In conclusion, biofilm formation may be suggested to play a role in mupirocin resistance besides the presence of a genetic element encoding abnormal isoleucyl-tRNA synthetase, however further studies are needed to confirm these findings. PMID:27436387

  17. Correlation of mupirocin resistance with biofilm production in methicillin-resistant Staphylococcus aureus from surgical site infections in a tertiary centre, Egypt.

    PubMed

    Barakat, Ghada I; Nabil, Yasmin M

    2016-03-01

    The aim of this study was to detect mupirocin-resistant isolates from pus/wound swabs taken postoperatively in a tertiary centre in Egypt and to determine their ability to form biofilm in order to establish its correlation with mupirocin resistance. This was a prospective study including 513pus/wound swabs from patients suffering from postoperative surgical site infections over the period July 2013-January 2015. Samples were cultured and isolates were identified by coagulase activity, DNase test, mannitol fermentation by mannitol salt agar followed by API Staph 32. Oxacillin agar screen test, agar dilution test for mupirocin, and mupA gene detection by PCR were performed for all methicillin-resistant Staphylococcus aureus (MRSA) isolates. Biofilm detection was carried out by the microtitre plate and Congo red agar methods. Of the 161 S. aureus isolates identified, 73 (45.3%) were MRSA, among which 82.2% were mupirocin-susceptible and 17.8% were mupirocin-resistant. Among the resistant isolates, 38.5% showed low-level resistance and 61.5% were high-level mupirocin-resistant. The mupA gene was detected in 75.0% of high-level mupirocin-resistant strains and in none of the low-level mupirocin-resistant strains. Among the mupirocin-susceptible isolates, 95.0% were biofilm-producers and 5.0% did not produce biofilm. All mupirocin-resistant isolates produced biofilm. Moreover, 15.3% of high-level mupirocin-resistant strains were negative for the mupA gene but showed evidence of biofilm formation. In conclusion, biofilm formation may be suggested to play a role in mupirocin resistance besides the presence of a genetic element encoding abnormal isoleucyl-tRNA synthetase, however further studies are needed to confirm these findings.

  18. Gamow-Teller strength distributions and stellar weak-interaction rates for ^{76}Ge and ^{82}Se using the deformed pn-QRPA model

    NASA Astrophysics Data System (ADS)

    Nabi, Jameel-Un; Ishfaq, Mavra

    2016-07-01

    We calculate Gamow-Teller strength distributions for β β-decay nuclei ^{76}Ge and ^{82}Se using the deformed pn-QRPA model. We use a deformed Nilsson basis and consider pairing correlations within the deformed BCS theory. Ground state correlations and two-particle and two-hole mixing states were included in our pn-QRPA model. Our calculated strength distributions were compared with experimental data and previous calculation. The total Gamow-Teller strength and centroid placement calculated in our model compares well with the measured value. We calculate β-decay and positron capture rates on ^{76}Ge and ^{82}Se in supernovae environments and compare them to those obtained from experimental data and previous calculation. Our study shows that positron capture rates command the total weak rates at high stellar temperatures. We also calculate energy rates of β-delayed neutrons and their emission probabilities.

  19. Structural and spectroscopic characterization and Hirshfeld surface analysis of major component of antibiotic mupirocin - pseudomonic acid A

    NASA Astrophysics Data System (ADS)

    Bojarska, J.; Maniukiewicz, W.; Fruziński, A.; Jędrzejczyk, M.; Wojciechowski, J.; Krawczyk, H.

    2014-11-01

    The crystal structure of pseudomonic acid A, the major component of antibiotic mupirocin, was determined from single-crystal X-ray diffraction data at low temperature (100 K). The compound crystallizes in the monoclinic system with non-centrosymmetric space group P21, with unit cell dimensions a = 12.4844(5), b = 5.0313(2), c = 21.5251(9) Å and β = 101.730(2)°, Z = 2. The molecules associate in dimers in head-to-tail motif through strong Osbnd H⋯O hydrogen bonds packed in the parallel arrangement along crystallographic axis b. Additionally, relatively weak Csbnd H⋯O and Csbnd H⋯π interactions form 3-D hydrogen bond framework. From the Hirshfeld surfaces and 2-D fingerprint analysis it was found that the subtle interactions, such as H⋯H, associating two-thirds of the all intercontacts, provide extra stabilization in addition to the presence of the mentioned above strong hydrogen bonds. The electrostatic potential mapped over the Hirshfeld surface visualizes electrostatic complementarities in the crystal packing. Results of X-ray diffraction and Monte Carlo methods reveal two conformations of n-alkyl chain of pseudomonic acid A, extended in the single-crystal and folded in the liquid state. A detailed interpretation of the FT-IR and NMR spectra were also reported. The TG and DTG results indicated that pseudomonic acid A is stable up to 210 °C.

  20. Supraspinatus and infraspinatus weakness in overhead athletes with scapular dyskinesis: strength assessment before and after restoration of scapular musculature balance.

    PubMed

    Merolla, Giovanni; De Santis, Elisa; Campi, Fabrizio; Paladini, Paolo; Porcellini, Giuseppe

    2010-12-01

    A disturbance in scapulohumeral rhythm may cause negative biomechanic effects on rotator cuff (RC). Alteration in scapular motion and shoulder pain can influence RC strength. Purpose of this study was to assess supraspinatus and infraspinatus strength in 29 overhead athletes with scapular dyskinesis, before and after 3 and 6 months of rehabilitation aimed to restore scapular musculature balance. A passive posterior soft tissues stretching was prescribed to balance shoulder mobility. Scapular dyskinesis patterns were evaluated according to Kibler et al. Clinical assessment was performed with the empty can (EC) test and infraspinatus strength test (IST). Strength values were recorded by a dynamometer; scores for pain were assessed with VAS scale. Changes of shoulder IR were measured. The force values increased at 3 months (P < 0.01) and at 6 months (P < 0.01). Changes of glenohumeral IR and decrease in pain scores were found at both follow-up. Outcomes registered on pain and strength confirm the role of a proper scapular position for an optimal length-tension relationship of the RC muscles. These data should encourage those caring for athletes to consider restoring of scapular musculature balance as essential part of the athletic training. PMID:21069487

  1. Molecular Characterization of High-Level Mupirocin Resistance in Staphylococcus pseudintermedius

    PubMed Central

    Pérez-Roth, Eduardo; Pintarić, Selma; Šeol Martinec, Branka

    2013-01-01

    The genetic analysis of high-level mupirocin resistance (Hi-Mupr) in a Staphylococcus pseudintermedius isolate from a dog is presented. The Hi-Mupr ileS2 gene flanked by a novel rearrangement of directly repeated insertion sequence IS257 elements was located, together with the aminoglycoside resistance aacA-aphD determinant, on a conjugative plasmid related to the pSK41/pGO1 family plasmids. PMID:23269741

  2. Efficacy of mupirocin and rifampin used with standard treatment in the management of acne vulgaris.

    PubMed

    Khorvash, Farzin; Abdi, Fatemeh; H Kashani, Hessam; Fatemi Naeini, Farahnaz; Khorvash, Fariborz

    2013-01-01

    The multiple etiologic factors involved in acne make the use of various medications necessary to treat the condition. This study aimed to determine the efficacy of mupirocin and rifampin used with standard treatment in the management of acne vulgaris. In a multicentre, randomized controlled, triple-blinded study, a total of 105 acne patients, with a clinical diagnosis of moderate to severe acne,were randomizedly divided into three groups (35 per group), for treatment of acne. The first group was treated with standard treatment alone, the second group received mupirocin plus standard treatment and the third group received rifampin plus standard treatment.There were three study visits according to Global Acne Grading System (GAGS): at baseline and weeks 6 and 12. The absolute changes of GAGS score from baseline to week 6 and 12 demonstrated a reduction in the mean score of GAGS in the three treatment groups (p < 0.001). Due to the difference between GAGS score at the baseline of study, the data were adjusted using the general linear model. The findings showed that all of the treatments significantly improved acne lesions. Nevertheless, none of the treatments was shown to be more effective than the others (p = 0.9). The three treatments were well tolerated, and no serious adverse events were reported. These findings provide evidence on the efficacy of combining mupirocin and rifampin with standard treatment in the management of acne vulgaris, although none of the treatments had superior efficacy compared with the others. PMID:24250593

  3. Comparison of mupirocin-based media for selective enumeration of bifidobacteria in probiotic supplements.

    PubMed

    Bunesova, Vera; Musilova, Sarka; Geigerova, Martina; Pechar, Radko; Rada, Vojtech

    2015-02-01

    An international standard already exists for the selective enumeration of bifidobacteria in milk products. This standard uses Transgalactosylated oligosaccharides (TOS) propionate agar supplemented with mupirocin. However, no such standard method has been described for the selective enumeration of bifidobacteria in probiotic supplements, where the presence of bifidobacteria is much more variable than in milk products. Therefore, we enumerated bifidobacteria by colony count technique in 13 probiotic supplements using three media supplemented with mupirocin (Mup; 100mg/l): TOS, Bifidobacteria selective medium (BSM) and modified Wilkins-Chalgren anaerobe agar with soya peptone (WSP). Moreover, the potential growth of bifidobacterial strains often used in probiotic products was performed in these media. All 13 products contained members of the genus Bifidobacterium, and tested mupirocin media were found to be fully selective for bifidobacteria. However, the type strain Bifidobacterium bifidum DSM 20456 and collection strain B. bifidum DSM 20239 showed statistically significant lower counts on TOS Mup media, compared to BSM Mup and WSP Mup media. Therefore, the TOS Mup medium recommended by the ISO standard cannot be regarded as a fully selective and suitable medium for the genus Bifidobacterium. In contrast, the BSM Mup and WSP Mup media supported the growth of all bifidobacterial species.

  4. Efficacy of Mupirocin and Rifampin Used with Standard Treatment in the Management of Acne Vulgaris

    PubMed Central

    Khorvash, Farzin; Abdi, Fatemeh; H.Kashani, Hessam; Fatemi Naeini, Farahnaz; Khorvash, Fariborz

    2013-01-01

    The multiple etiologic factors involved in acne make the use of various medications necessary to treat the condition. This study aimed to determine the efficacy of mupirocin and rifampin used with standard treatment in the management of acne vulgaris. In a multicentre, randomized controlled, triple-blinded study, a total of 105 acne patients, with a clinical diagnosis of moderate to severe acne,were randomizedly divided into three groups (35 per group), for treatment of acne. The first group was treated with standard treatment alone, the second group received mupirocin plus standard treatment and the third group received rifampin plus standard treatment.There were three study visits according to Global Acne Grading System (GAGS): at baseline and weeks 6 and 12. The absolute changes of GAGS score from baseline to week 6 and 12 demonstrated a reduction in the mean score of GAGS in the three treatment groups (p < 0.001). Due to the difference between GAGS score at the baseline of study, the data were adjusted using the general linear model. The findings showed that all of the treatments significantly improved acne lesions. Nevertheless, none of the treatments was shown to be more effective than the others (p = 0.9). The three treatments were well tolerated, and no serious adverse events were reported. These findings provide evidence on the efficacy of combining mupirocin and rifampin with standard treatment in the management of acne vulgaris, although none of the treatments had superior efficacy compared with the others. PMID:24250593

  5. Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clones with high-level mupirocin resistance.

    PubMed

    González-Domínguez, María; Seral, Cristina; Potel, Carmen; Sáenz, Yolanda; Álvarez, Maximiliano; Torres, Carmen; Castillo, Francisco Javier

    2016-06-01

    A high proportion of methicillin-resistant Staphylococcus aureus isolates recovered in one year period showed high-level mupirocin-resistance (HLMUPR-MRSA) in our environment (27.2%). HLMUPR-MRSA isolates were mainly collected from skin and soft tissue samples, and diabetes was the main related comorbidity condition. These isolates were more frequently found in vascular surgery. HLMUPR-MRSA was more resistant to aminoglycosides than mupirocin-susceptible MRSA, linked to the presence of bifunctional and/or nucleotidyltransferase enzymes with/without macrolide resistance associated with the msr(A) gene. Most of HLMUPR-MRSA isolates belonged to ST125/t067. Nine IS257-ileS2 amplification patterns (p3 was the most frequent) were observed in HLMUPR-MRSA isolates, suggesting the presence of several mupirocin-resistance-carrying plasmids in our environment and promoting the emergence of mupirocin resistance. The presence of the same IS257-ileS2 amplification pattern p3 in 65% of HLMUPR-MRSA, all of them ST125/t067, suggests a clonal spread in our hospital and community environment which could explain the high prevalence of HLMUPR-MRSA during the study period. An outbreak situation or an increase in mupirocin consumption was not observed.

  6. Analysis of rILERS, an isoleucyl-tRNA synthetase gene associated with mupirocin production by Pseudomonas fluorescens NCIMB 10586.

    PubMed

    Rangaswamy, Vidhya; Hernández-Guzmán, Gustavo; Shufran, Kevin A; Bender, Carol L

    2002-12-01

    Some strains of Pseudomonas fluorescens produce the antibiotic mupirocin, which functions as a competitive inhibitor of isoleucyl-tRNA synthetase (ILERS). Mupirocin-producing strains of P. fluorescens must overcome the inhibitory effects of the antibiotic to avoid self-suicide. However, it is not clear how P. fluorescens protects itself from the toxic effects of mupirocin. In this report, we describe a second gene encoding isoleucyl-tRNA synthetase (rILERS) in P. fluorescens that is associated with the mupirocin biosynthetic gene cluster. Random mutagenesis of the mupirocin-producing strain, P. fluorescens 10586, resulted in a mupirocin-defective mutant disrupted in a region with similarity to ILERS, the target site for mupirocin. The ILERS gene described in the present study was sequenced and shown to be encoded by a 3093 bp ORF, which is 264 bp larger than the ILERS gene previously identified in P. fluorescens 10586. rILERS from P. fluorescens is most closely related to prokaryotic or eukaryotic sources of ILERS that are resistant to mupirocin. Interestingly, the relatedness between rILERS and the ILERS previously described in P. fluorescens 10586 was low (24% similarity), which indicates that P. fluorescens contains two isoforms of isoleucyl-tRNA synthetase.

  7. Strength and weaknesses of modeling the dynamics of mode-locked lasers by means of collective coordinates

    NASA Astrophysics Data System (ADS)

    Alsaleh, M.; Mback, C. B. L.; Tchomgo Felenou, E.; Tchofo Dinda, P.; Grelu, Ph; Porsezian, K.

    2016-07-01

    We address the efficiency of theoretical tools used in the development and optimization of mode-locked fiber lasers. Our discussion is based on the practical case of modeling the dynamics of a dispersion-managed fiber laser. One conventional approach uses discrete propagation equations, followed by the analysis of the numerical results through a collective coordinate projection. We compare the latter with our dynamical collective coordinate approach (DCCA), which combines both modeling and analysis in a compact form. We show that for single pulse dynamics, the DCCA allows a much quicker solution mapping in the space of cavity parameters than the conventional approach, along with a good accuracy. We also discuss the weaknesses of the DCCA, in particular when multiple pulsing bifurcations occur.

  8. Time-resolved carrier dynamics and electron-phonon coupling strength in proximized weak ferromagnet-superconductor nanobilayers

    NASA Astrophysics Data System (ADS)

    Taneda, T.; Pepe, G. P.; Parlato, L.; Golubov, A. A.; Sobolewski, Roman

    2007-05-01

    We present our femtosecond optical pump-probe studies of proximized ferromagnet-superconductor nanobilayers. The weak ferromagnetic nature of a thin NiCu film makes it possible to observe the dynamics of the nonequilibrium carriers through the near-surface optical reflectivity change measurements. The subpicosecond biexponential reflectivity decay has been identified as electron-phonon Debye and acoustic phonon relaxation times, and the decay of Debye phonons versus temperature dependence was used to evaluate the electron-phonon coupling constants for both the pure Nb and proximized Nb/NiCu heterostructures down to low temperatures. We have also demonstrated that the NiCu overlay on top of Nb dramatically reduced the slow, bolometric component of the photoresponse component, making such bilayers attractive for future radiation detector applications.

  9. SWOT analysis of Banff: strengths, weaknesses, opportunities and threats of the international Banff consensus process and classification system for renal allograft pathology.

    PubMed

    Mengel, M; Sis, B; Halloran, P F

    2007-10-01

    The Banff process defined the diagnostic histologic lesions for renal allograft rejection and created a standardized classification system where none had existed. By correcting this deficit the process had universal impact on clinical practice and clinical and basic research. All trials of new drugs since the early 1990s benefited, because the Banff classification of lesions permitted the end point of biopsy-proven rejection. The Banff process has strengths, weaknesses, opportunities and threats (SWOT). The strength is its self-organizing group structure to create consensus. Consensus does not mean correctness: defining consensus is essential if a widely held view is to be proved wrong. The weaknesses of the Banff process are the absence of an independent external standard to test the classification; and its almost exclusive reliance on histopathology, which has inherent limitations in intra- and interobserver reproducibility, particularly at the interface between borderline and rejection, is exactly where clinicians demand precision. The opportunity lies in the new technology such as transcriptomics, which can form an external standard and can be incorporated into a new classification combining the elegance of histopathology and the objectivity of transcriptomics. The threat is the degree to which the renal transplant community will participate in and support this process. PMID:17848174

  10. Studies of a weak polyampholyte at the air-buffer interface: The effect of varying pH and ionic strength

    NASA Astrophysics Data System (ADS)

    Cicuta, Pietro; Hopkinson, Ian

    2001-05-01

    We have carried out experiments to probe the static and dynamic interfacial properties of β-casein monolayers spread at the air-buffer interface, and analyzed these results in the context of models of weak polyampholytes. Measurements have been made systematically over a wide range of ionic strength and pH. In the semidilute regime of surface concentration a scaling exponent, which can be linked to the degree of chain swelling, is found. This shows that at pH close to the isoelectric point, the protein is compact. At pH away from the isoelectric pH the protein is extended. The transition between compact and extended states is continuous. As a function of increasing ionic strength, we observe swelling of the protein at the isoelectric pH but contraction of the protein at pH values away from it. These behaviors are typical of a those predicted theoretically for a weak polyampholyte. Dilational moduli measurements, made as a function of surface concentration exhibit maxima that are linked to the collapse of hydrophilic regions of the protein into the subphase. Based on this data we present a configuration map of the protein configuration in the monolayer. These findings are supported by strain (surface pressure) relaxation measurements and surface quasielastic light scattering measurements which suggest the existence of loops and tails in the subphase at higher surface concentrations.

  11. SWOT analysis of Banff: strengths, weaknesses, opportunities and threats of the international Banff consensus process and classification system for renal allograft pathology.

    PubMed

    Mengel, M; Sis, B; Halloran, P F

    2007-10-01

    The Banff process defined the diagnostic histologic lesions for renal allograft rejection and created a standardized classification system where none had existed. By correcting this deficit the process had universal impact on clinical practice and clinical and basic research. All trials of new drugs since the early 1990s benefited, because the Banff classification of lesions permitted the end point of biopsy-proven rejection. The Banff process has strengths, weaknesses, opportunities and threats (SWOT). The strength is its self-organizing group structure to create consensus. Consensus does not mean correctness: defining consensus is essential if a widely held view is to be proved wrong. The weaknesses of the Banff process are the absence of an independent external standard to test the classification; and its almost exclusive reliance on histopathology, which has inherent limitations in intra- and interobserver reproducibility, particularly at the interface between borderline and rejection, is exactly where clinicians demand precision. The opportunity lies in the new technology such as transcriptomics, which can form an external standard and can be incorporated into a new classification combining the elegance of histopathology and the objectivity of transcriptomics. The threat is the degree to which the renal transplant community will participate in and support this process.

  12. The Reliability and Validity of the English and Spanish Strengths and Weaknesses of ADHD and Normal Behavior Rating Scales in a Preschool Sample: Continuum Measures of Hyperactivity and Inattention

    ERIC Educational Resources Information Center

    Lakes, Kimberley D.; Swanson, James M.; Riggs, Matt

    2012-01-01

    Objective: To evaluate the reliability and validity of the English and Spanish versions of the Strengths and Weaknesses of ADHD-symptom and Normal-behavior (SWAN) rating scale. Method: Parents of preschoolers completed both a SWAN and the well-established Strengths and Difficulties Questionnaire (SDQ) on two separate occasions over a span of 3…

  13. Multiplex PCR assay for identification of six different Staphylococcus spp. and simultaneous detection of methicillin and mupirocin resistance.

    PubMed

    Campos-Peña, E; Martín-Nuñez, E; Pulido-Reyes, G; Martín-Padrón, J; Caro-Carrillo, E; Donate-Correa, J; Lorenzo-Castrillejo, I; Alcoba-Flórez, J; Machín, F; Méndez-Alvarez, S

    2014-07-01

    We describe a new, efficient, sensitive, and fast single-tube multiple-PCR protocol for the identification of the most clinically significant Staphylococcus spp. and the simultaneous detection of the methicillin and mupirocin resistance loci. The protocol identifies at the species level isolates belonging to S. aureus, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, and S. saprophyticus.

  14. Multiplex PCR assay for identification of six different Staphylococcus spp. and simultaneous detection of methicillin and mupirocin resistance.

    PubMed

    Campos-Peña, E; Martín-Nuñez, E; Pulido-Reyes, G; Martín-Padrón, J; Caro-Carrillo, E; Donate-Correa, J; Lorenzo-Castrillejo, I; Alcoba-Flórez, J; Machín, F; Méndez-Alvarez, S

    2014-07-01

    We describe a new, efficient, sensitive, and fast single-tube multiple-PCR protocol for the identification of the most clinically significant Staphylococcus spp. and the simultaneous detection of the methicillin and mupirocin resistance loci. The protocol identifies at the species level isolates belonging to S. aureus, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, and S. saprophyticus. PMID:24829244

  15. Spatial Noise in Coupling Strength and Natural Frequency within a Pacemaker Network; Consequences for Development of Intestinal Motor Patterns According to a Weakly Coupled Phase Oscillator Model.

    PubMed

    Parsons, Sean P; Huizinga, Jan D

    2016-01-01

    Pacemaker activities generated by networks of interstitial cells of Cajal (ICC), in conjunction with the enteric nervous system, orchestrate most motor patterns in the gastrointestinal tract. It was our objective to understand the role of network features of ICC associated with the myenteric plexus (ICC-MP) in the shaping of motor patterns of the small intestine. To that end, a model of weakly coupled oscillators (oscillators influence each other's phase but not amplitude) was created with most parameters derived from experimental data. The ICC network is a uniform two dimensional network coupled by gap junctions. All ICC generate pacemaker (slow wave) activity with a frequency gradient in mice from 50/min at the proximal end of the intestine to 40/min at the distal end. Key features of motor patterns, directly related to the underlying pacemaker activity, are frequency steps and dislocations. These were accurately mimicked by reduction of coupling strength at a point in the chain of oscillators. When coupling strength was expressed as a product of gap junction density and conductance, and gap junction density was varied randomly along the chain (i.e., spatial noise) with a long-tailed distribution, plateau steps occurred at pointsof low density. As gap junction conductance was decreased, the number of plateaus increased, mimicking the effect of the gap junction inhibitor carbenoxolone. When spatial noise was added to the natural interval gradient, as gap junction conductance decreased, the number of plateaus increased as before but in addition the phase waves frequently changed direction of apparent propagation, again mimicking the effect of carbenoxolone. In summary, key features of the motor patterns that are governed by pacemaker activity may be a direct consequence of biological noise, specifically spatial noise in gap junction coupling and pacemaker frequency. PMID:26869875

  16. Spatial Noise in Coupling Strength and Natural Frequency within a Pacemaker Network; Consequences for Development of Intestinal Motor Patterns According to a Weakly Coupled Phase Oscillator Model

    PubMed Central

    Parsons, Sean P.; Huizinga, Jan D.

    2016-01-01

    Pacemaker activities generated by networks of interstitial cells of Cajal (ICC), in conjunction with the enteric nervous system, orchestrate most motor patterns in the gastrointestinal tract. It was our objective to understand the role of network features of ICC associated with the myenteric plexus (ICC-MP) in the shaping of motor patterns of the small intestine. To that end, a model of weakly coupled oscillators (oscillators influence each other's phase but not amplitude) was created with most parameters derived from experimental data. The ICC network is a uniform two dimensional network coupled by gap junctions. All ICC generate pacemaker (slow wave) activity with a frequency gradient in mice from 50/min at the proximal end of the intestine to 40/min at the distal end. Key features of motor patterns, directly related to the underlying pacemaker activity, are frequency steps and dislocations. These were accurately mimicked by reduction of coupling strength at a point in the chain of oscillators. When coupling strength was expressed as a product of gap junction density and conductance, and gap junction density was varied randomly along the chain (i.e., spatial noise) with a long-tailed distribution, plateau steps occurred at pointsof low density. As gap junction conductance was decreased, the number of plateaus increased, mimicking the effect of the gap junction inhibitor carbenoxolone. When spatial noise was added to the natural interval gradient, as gap junction conductance decreased, the number of plateaus increased as before but in addition the phase waves frequently changed direction of apparent propagation, again mimicking the effect of carbenoxolone. In summary, key features of the motor patterns that are governed by pacemaker activity may be a direct consequence of biological noise, specifically spatial noise in gap junction coupling and pacemaker frequency. PMID:26869875

  17. Predicted and measured concentrations of pharmaceuticals in hospital effluents. Examination of the strengths and weaknesses of the two approaches through the analysis of a case study.

    PubMed

    Verlicchi, Paola; Zambello, Elena

    2016-09-15

    This study deals with the chemical characterization of hospital effluents in terms of the predicted and measured concentrations of 38 pharmaceuticals belonging to 11 different therapeutic classes. The paper outlines the strengths and weaknesses of the two approaches through an analysis of a case study referring to a large hospital. It highlights the observed (and expected) ranges of variability for the parameters of the adopted model, presents the results of an uncertainty analysis of direct measurements (due to sampling mode and frequency and chemical analysis) and a sensitivity analysis of predicted concentrations (based on the annual consumption of pharmaceuticals, their excretion rate and annual wastewater volume generated by the hospital). Measured concentrations refer to two sampling campaigns carried out in summer and winter in order to investigate seasonal variability of the selected compounds. Predicted concentrations are compared to measured ones in the three scenarios: summer, winter and the whole year. It was found that predicted and measured concentrations are in agreement for a limited number of compounds (namely atenolol, atorvastatin and hydrochlorothiazide), and for most compounds the adoption of the model leads to a large overestimation in all three periods. Uncertainties in predictions are mainly due to the wastewater volume and excretion factor, whereas for measured concentrations, uncertainties are mainly due to sampling mode. PMID:27161130

  18. Comparative study of mupirocin and oral co-trimoxazole plus topical fusidic acid in eradication of nasal carriage of methicillin-resistant Staphylococcus aureus.

    PubMed Central

    Parras, F; Guerrero, M C; Bouza, E; Blázquez, M J; Moreno, S; Menarguez, M C; Cercenado, E

    1995-01-01

    Mupirocin is a topically applied drug that is very active in the eradication of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). However, studies designed to compare mupirocin treatment with other antimicrobial regimens are lacking. We therefore conducted an open, prospective, randomized, controlled trial to compare the efficacy and safety of mupirocin versus those of oral co-trimoxazole plus topical fusidic acid (both regimens with a clorhexidine scrub bath) for the eradication of MRSA from nasal and extranasal carriers of MRSA. The eradication rates with mupirocin and co-trimoxazole plus fusidic acid at 2, 7, 14, 21, 28, and 90 days were 93 and of 93, 100 and 100, 97 and 94, 100 and 92, 96 and 95, and 78 and 71%, respectively, for nasal carriage. At 7, 14, and 28 days the eradication rates for extranasal carriage by the two regimens were 23 and 74, 83 and 76, and 45 and 69%, respectively. The efficacies and safety of both regimens were similar. The MRSA isolates were not resistant to the study drugs either at the baseline or at follow-up. These results suggest that mupirocin and co-trimoxazole plus fusidic acid, both used in conjunction with a chlorhexidine soap bath, are equally effective and safe for the eradication of MRSA from nasal and extranasal MRSA carriers. Mupirocin was easier to use but was more expensive. PMID:7695302

  19. Targeted Intranasal Mupirocin To Prevent Colonization and Infection by Community-Associated Methicillin-Resistant Staphylococcus aureus Strains in Soldiers: a Cluster Randomized Controlled Trial▿

    PubMed Central

    Ellis, Michael W.; Griffith, Matthew E.; Dooley, David P.; McLean, Joseph C.; Jorgensen, James H.; Patterson, Jan E.; Davis, Kepler A.; Hawley, Joshua S.; Regules, Jason A.; Rivard, Robert G.; Gray, Paula J.; Ceremuga, Julia M.; DeJoseph, Mary A.; Hospenthal, Duane R.

    2007-01-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen that primarily manifests as uncomplicated skin and soft tissue infections. We conducted a cluster randomized, double-blind, placebo-controlled trial to determine whether targeted intranasal mupirocin therapy in CA-MRSA-colonized soldiers could prevent infection in the treated individual and prevent new colonization and infection within their study groups. We screened 3,447 soldiers comprising 14 training classes for CA-MRSA colonization from January to December 2005. Each training class was randomized to either the mupirocin or placebo study group, and the participants identified as CA-MRSA colonized were treated with either mupirocin or placebo. All participants underwent repeat screening after 8 to 10 weeks and were monitored for 16 weeks for development of infection. Of 3,447 participants screened, 134 (3.9%) were initially colonized with CA-MRSA. Five of 65 (7.7%; 95% confidence interval [95% CI], 4.0% to 11.4%) placebo-treated participants and 7 of 66 (10.6%; 95% CI, 7.9% to 13.3%) mupirocin-treated participants developed infections; the difference in the infection rate of the placebo- and mupirocin-treated groups was −2.9% (95% CI, −7.5% to 1.7%). Of those not initially colonized with CA-MRSA, 63 of 1,459 (4.3%; 95% CI, 2.7% to 5.9%) of the placebo group and 56 of 1,607 (3.5%; 95% CI, 2.6% to 5.2%) of the mupirocin group developed infections; the difference in the infection rate of the placebo and mupirocin groups was 0.8% (95% CI, −1.0% to 2.7%). Of 3,447 participants, 3,066 (89%) were available for the second sampling and completed follow-up. New CA-MRSA colonization occurred in 24 of 1,459 (1.6%; 95% CI, 0.05% to 2.8%) of the placebo group participants and 23 of 1,607 (1.4%; 95% CI, 0.05% to 2.3%) of the mupirocin group participants; the difference in the infection rate of the placebo and mupirocin groups was 0.2% (95% CI, −1.3% to 1.7%). Despite CA

  20. Quorum-sensing-dependent regulation of biosynthesis of the polyketide antibiotic mupirocin in Pseudomonas fluorescens NCIMB 10586.

    PubMed

    El-Sayed, A K; Hothersall, J; Thomas, C M

    2001-08-01

    Mupirocin (pseudomonic acid) is a polyketide antibiotic, targeting isoleucyl-tRNA synthase, and produced by Pseudomonas fluorescens NCIMB 10586. It is used clinically as a topical treatment for staphylococcal infections, particularly in contexts where there is a problem with methicillin-resistant Staphylococcus aureus (MRSA). In studying the mupirocin biosynthetic cluster the authors identified two putative regulatory genes, mupR and mupI, whose predicted amino acid sequences showed significant identity to proteins involved in quorum-sensing-dependent regulatory systems such as LasR/LuxR (transcriptional activators) and LasI/LuxI (synthases for N-acylhomoserine lactones--AHLs--that activate LasR/LuxR). Inactivation by deletion mutations using a suicide vector strategy confirmed the requirement for both genes in mupirocin biosynthesis. Cross-feeding experiments between bacterial strains as well as solvent extraction showed that, as predicted, wild-type P. fluorescens NCIMB 10586 produces a diffusible substance that overcomes the defect of a mupI mutant. Use of biosensor strains showed that the MupI product can activate the Pseudomonas aeruginosa lasRlasI system and that P. aeruginosa produces one or more compounds that can replace the MupI product. Insertion of a xylE reporter gene into mupA, the first ORF of the mupirocin biosynthetic operon, showed that together mupR/mupI control expression of the operon in such a way that the cluster is switched on late in exponential phase and in stationary phase.

  1. A Novel Chimeric Lysin Shows Superiority to Mupirocin for Skin Decolonization of Methicillin-Resistant and -Sensitive Staphylococcus aureus Strains▿

    PubMed Central

    Pastagia, Mina; Euler, Chad; Chahales, Peter; Fuentes-Duculan, Judilyn; Krueger, James G.; Fischetti, Vincent A.

    2011-01-01

    Staphylococcus aureus is a major human pathogen responsible for a number of serious and sometimes fatal infections. One of its reservoirs on the human body is the skin, which is known to be a source of invasive infection. The potential for an engineered staphylococcus-specific phage lysin (ClyS) to be used for topical decolonization is presented. We formulated ClyS into an ointment and applied it to a mouse model of skin colonization/infection with S. aureus. Unlike the standard topical antibacterial agent mupirocin, ClyS eradicated a significantly greater number of methicillin-susceptible S. aureus (MSSA) and -resistant S. aureus (MRSA) bacteria: a 3-log reduction with ClyS as opposed to a 2-log reduction with mupirocin in our model. The use of ClyS also demonstrated a decreased potential for the development of resistance by MRSA and MSSA organisms compared to that from the use of mupirocin in vitro. Because antibodies may affect enzyme function, we tested antibodies developed after repeated ClyS exposure for their effect on ClyS killing ability. Our results showed no inhibition of ClyS activity at various antibody titers. These data demonstrate the potential of developing ClyS as a novel class of topical antimicrobial agents specific to staphylococcus. PMID:21098252

  2. Strengths and weaknesses of Global Positioning System (GPS) data-loggers and semi-structured interviews for capturing fine-scale human mobility: findings from Iquitos, Peru.

    PubMed

    Paz-Soldan, Valerie A; Reiner, Robert C; Morrison, Amy C; Stoddard, Steven T; Kitron, Uriel; Scott, Thomas W; Elder, John P; Halsey, Eric S; Kochel, Tadeusz J; Astete, Helvio; Vazquez-Prokopec, Gonzalo M

    2014-06-01

    Quantifying human mobility has significant consequences for studying physical activity, exposure to pathogens, and generating more realistic infectious disease models. Location-aware technologies such as Global Positioning System (GPS)-enabled devices are used increasingly as a gold standard for mobility research. The main goal of this observational study was to compare and contrast the information obtained through GPS and semi-structured interviews (SSI) to assess issues affecting data quality and, ultimately, our ability to measure fine-scale human mobility. A total of 160 individuals, ages 7 to 74, from Iquitos, Peru, were tracked using GPS data-loggers for 14 days and later interviewed using the SSI about places they visited while tracked. A total of 2,047 and 886 places were reported in the SSI and identified by GPS, respectively. Differences in the concordance between methods occurred by location type, distance threshold (within a given radius to be considered a match) selected, GPS data collection frequency (i.e., 30, 90 or 150 seconds) and number of GPS points near the SSI place considered to define a match. Both methods had perfect concordance identifying each participant's house, followed by 80-100% concordance for identifying schools and lodgings, and 50-80% concordance for residences and commercial and religious locations. As the distance threshold selected increased, the concordance between SSI and raw GPS data increased (beyond 20 meters most locations reached their maximum concordance). Processing raw GPS data using a signal-clustering algorithm decreased overall concordance to 14.3%. The most common causes of discordance as described by a sub-sample (n=101) with whom we followed-up were GPS units being accidentally off (30%), forgetting or purposely not taking the units when leaving home (24.8%), possible barriers to the signal (4.7%) and leaving units home to recharge (4.6%). We provide a quantitative assessment of the strengths and weaknesses of

  3. Evaluation and intercomparison of downscaled daily precipitation indices over Japan in present-day climate: Strengths and weaknesses of dynamical and bias correction-type statistical downscaling methods

    NASA Astrophysics Data System (ADS)

    Iizumi, Toshichika; Nishimori, Motoki; Dairaku, Koji; Adachi, Sachiho A.; Yokozawa, Masayuki

    2011-01-01

    In this study, we evaluate the accuracy of four regional climate models (NHRCM, NRAMS, TRAMS, and TWRF) and one bias correction-type statistical model (CDFDM) for daily precipitation indices under the present-day climate (1985-2004) over Japan on a 20 km grid interval. The evaluated indices are (1) mean precipitation, (2) number of days with precipitation ≥1 mm/d (corresponds to number of wet days), (3) mean amount per wet day, (4) 90th percentile of daily precipitation, and (5) number of days with precipitation ≥90th percentile of daily precipitation. The boundary conditions of the dynamical models and the predictors of the statistical model are given from the single reanalysis data, i.e., JRA25. Both types of models successfully improved the accuracy of the indices relative to the reanalysis data in terms of bias, seasonal cycle, geographical pattern, cumulative distribution function of wet-day amount, and interannual variation pattern. In most aspects, NHRCM is the best model of all indices. Through the intercomparison between the dynamical and statistical models, respective strengths and weaknesses emerged. Briefly, (1) many dynamical models simulate too many wet days with a small amount of precipitation in humid climate zones, such as summer in Japan, relative to the statistical model, unless the cumulus convection scheme improved for such a condition is incorporated; (2) a few dynamical models can derive a better high-order percentile of daily precipitation (e.g., 90th percentile) than the statistical model; (3) both the dynamical and statistical models are still insufficient in the representation of the interannual variation pattern of the number of days with precipitation ≥90th percentile of daily precipitation; (4) the statistical model is comparable to the dynamical models in the long-term mean geographical pattern of the indices even on a 20 km grid interval if a dense observation network is applicable; (5) the statistical model is less accurate

  4. Strengths and Weaknesses of Global Positioning System (GPS) Data-Loggers and Semi-structured Interviews for Capturing Fine-scale Human Mobility: Findings from Iquitos, Peru

    PubMed Central

    Paz-Soldan, Valerie A.; Reiner, Robert C.; Morrison, Amy C.; Stoddard, Steven T.; Kitron, Uriel; Scott, Thomas W.; Elder, John P.; Halsey, Eric S.; Kochel, Tadeusz J.; Astete, Helvio; Vazquez-Prokopec, Gonzalo M.

    2014-01-01

    Quantifying human mobility has significant consequences for studying physical activity, exposure to pathogens, and generating more realistic infectious disease models. Location-aware technologies such as Global Positioning System (GPS)-enabled devices are used increasingly as a gold standard for mobility research. The main goal of this observational study was to compare and contrast the information obtained through GPS and semi-structured interviews (SSI) to assess issues affecting data quality and, ultimately, our ability to measure fine-scale human mobility. A total of 160 individuals, ages 7 to 74, from Iquitos, Peru, were tracked using GPS data-loggers for 14 days and later interviewed using the SSI about places they visited while tracked. A total of 2,047 and 886 places were reported in the SSI and identified by GPS, respectively. Differences in the concordance between methods occurred by location type, distance threshold (within a given radius to be considered a match) selected, GPS data collection frequency (i.e., 30, 90 or 150 seconds) and number of GPS points near the SSI place considered to define a match. Both methods had perfect concordance identifying each participant's house, followed by 80–100% concordance for identifying schools and lodgings, and 50–80% concordance for residences and commercial and religious locations. As the distance threshold selected increased, the concordance between SSI and raw GPS data increased (beyond 20 meters most locations reached their maximum concordance). Processing raw GPS data using a signal-clustering algorithm decreased overall concordance to 14.3%. The most common causes of discordance as described by a sub-sample (n = 101) with whom we followed-up were GPS units being accidentally off (30%), forgetting or purposely not taking the units when leaving home (24.8%), possible barriers to the signal (4.7%) and leaving units home to recharge (4.6%). We provide a quantitative assessment of the strengths and

  5. Parallel inhibition of active force and relaxed fiber stiffness by caldesmon fragments at physiological ionic strength and temperature conditions: additional evidence that weak cross-bridge binding to actin is an essential intermediate for force generation.

    PubMed Central

    Kraft, T; Chalovich, J M; Yu, L C; Brenner, B

    1995-01-01

    Previously we showed that stiffness of relaxed fibers and active force generated in single skinned fibers of rabbit psoas muscle are inhibited in parallel by actin-binding fragments of caldesmon, an actin-associated protein of smooth muscle, under conditions in which a large fraction of cross-bridges is weakly attached to actin (ionic strength of 50 mM and temperature of 5 degrees C). These results suggested that weak cross-bridge attachment to actin is essential for force generation. The present study provides evidence that this is also true for physiological ionic strength (170 mM) at temperatures up to 30 degrees C, suggesting that weak cross-bridge binding to actin is generally required for force generation. In addition, we show that the inhibition of active force is not a result of changes in cross-bridge cycling kinetics but apparently results from selective inhibition of weak cross-bridge binding to actin. Together with our previous biochemical, mechanical, and structural studies, these findings support the proposal that weak cross-bridge attachment to actin is an essential intermediate on the path to force generation and are consistent with the concept that isometric force mainly results from an increase in strain of the attached cross-bridge as a result of a structural change associated with the transition from a weakly bound to a strongly bound actomyosin complex. This mechanism is different from the processes responsible for quick tension recovery that were proposed by Huxley and Simmons (Proposed mechanism of force generation in striated muscle. Nature. 233:533-538.) to represent the elementary mechanism of force generation. Images FIGURE 1 PMID:7647245

  6. From Weakness to Strength: C-H/π-Interaction-Guided Self-Assembly and Gelation of Poly(benzyl ether) Dendrimers.

    PubMed

    Peng, Yi; Feng, Yu; Deng, Guo-Jun; He, Yan-Mei; Fan, Qing-Hua

    2016-09-13

    The C-H/π interactions as the key driving force for the construction of supramolecular gels remain a great challenge because of their weak nature. We hereby employed for the first time weak C-H/π interactions for the construction of supramolecular dendritic gels based on peripherally methyl-functionalized poly(benzyl ether) dendrimers. Their gelation property is highly dependent on the nature of the peripheral methyl groups. Furthermore, single-crystal X-ray analysis and NMR spectroscopy revealed that multiple C-H/π interactions between the proton of the methyl group and the electron-rich peripheral methyl-substituted aryl ring played significant roles in the formation of supramolecular nanofibers and organogels. This study uncovers the critical role of weak noncovalent interactions and provides new insights into the further design of self-assembled nanomaterials.

  7. From Weakness to Strength: C-H/π-Interaction-Guided Self-Assembly and Gelation of Poly(benzyl ether) Dendrimers.

    PubMed

    Peng, Yi; Feng, Yu; Deng, Guo-Jun; He, Yan-Mei; Fan, Qing-Hua

    2016-09-13

    The C-H/π interactions as the key driving force for the construction of supramolecular gels remain a great challenge because of their weak nature. We hereby employed for the first time weak C-H/π interactions for the construction of supramolecular dendritic gels based on peripherally methyl-functionalized poly(benzyl ether) dendrimers. Their gelation property is highly dependent on the nature of the peripheral methyl groups. Furthermore, single-crystal X-ray analysis and NMR spectroscopy revealed that multiple C-H/π interactions between the proton of the methyl group and the electron-rich peripheral methyl-substituted aryl ring played significant roles in the formation of supramolecular nanofibers and organogels. This study uncovers the critical role of weak noncovalent interactions and provides new insights into the further design of self-assembled nanomaterials. PMID:27538342

  8. Randomized, controlled trial of topical exit-site application of honey (Medihoney) versus mupirocin for the prevention of catheter-associated infections in hemodialysis patients.

    PubMed

    Johnson, David Wayne; van Eps, Carolyn; Mudge, David William; Wiggins, Kathryn Joan; Armstrong, Kirsty; Hawley, Carmel Mary; Campbell, Scott Bryan; Isbel, Nicole Maree; Nimmo, Graeme Robert; Gibbs, Harry

    2005-05-01

    The clinical usefulness of hemodialysis catheters is limited by increased infectious morbidity and mortality. Topical antiseptic agents, such as mupirocin, are effective at reducing this risk but have been reported to select for antibiotic-resistant strains. The aim of the present study was to determine the efficacy and the safety of exit-site application of a standardized antibacterial honey versus mupirocin in preventing catheter-associated infections. A randomized, controlled trial was performed comparing the effect of thrice-weekly exit-site application of Medihoney versus mupirocin on infection rates in patients who were receiving hemodialysis via tunneled, cuffed central venous catheters. A total of 101 patients were enrolled. The incidences of catheter-associated bacteremias in honey-treated (n = 51) and mupirocin-treated (n = 50) patients were comparable (0.97 versus 0.85 episodes per 1000 catheter-days, respectively; NS). On Cox proportional hazards model analysis, the use of honey was not significantly associated with bacteremia-free survival (unadjusted hazard ratio, 0.94; 95% confidence interval, 0.27 to 3.24; P = 0.92). No exit-site infections occurred. During the study period, 2% of staphylococcal isolates within the hospital were mupirocin resistant. Thrice-weekly application of standardized antibacterial honey to hemodialysis catheter exit sites was safe, cheap, and effective and resulted in a comparable rate of catheter-associated infection to that obtained with mupirocin (although the study was not adequately powered to assess therapeutic equivalence). The effectiveness of honey against antibiotic-resistant microorganisms and its low likelihood of selecting for further resistant strains suggest that this agent may represent a satisfactory alternative means of chemoprophylaxis in patients with central venous catheters.

  9. Topical Bactroban (mupirocin): efficacy in treating burn wounds infected with methicillin-resistant staphylococci.

    PubMed

    Strock, L L; Lee, M M; Rutan, R L; Desai, M H; Robson, M C; Herndon, D N; Heggers, J P

    1990-01-01

    Bacterial antimicrobial susceptibility predictors such as the minimal inhibitory concentration (MIC) assay and Nathans Agar Well Diffusion (NAWD) assay provide essential information relevant to the therapeutic approach in burn-wound sepsis. The susceptibilities of 68 gram-positive burn-wound isolates were tested against topical Bactroban (mupirocin) (Beecham Laboratories, Bristol, Tenn.) and compared with other topical antimicrobials such as mafenide acetate, silver sulfadiazine, and bacitracin/neomycin/polymyxin (BNP). Topical susceptibility data were obtained with a modification of NAWD assay. Bactroban's antimicrobial activity was greater than that of mafenide acetate (100% vs 97%), and significantly greater than that of silver sulfadiazine and that of BNP (p less than 0.001). Of the 68 isolates that were susceptible to Bactroban, 51 were predominately methicillin-resistant staphylococci (MRSA). Bactroban showed in vitro activity against 71% of the 85 gram-negative isolates tested. Mafenide acetate showed activity against 89% of these isolates, a significant difference compared with Bactroban (p less than 0.02). In general, no significant difference was found between the activities of Bactroban and silver sulfadiazine against the gram-negative isolates. The activities of mafenide acetate and silver sulfadiazine against isolates of Pseudomonas aeruginosa were significantly greater than that of Bactroban (p less than 0.05). Bactroban may be used in the treatment of documented staphylococcal burn-wound infections. On the basis of the in vitro data, 13 patients with MRSA burn-wound infections susceptible to Bactroban were evaluated. Quantitative wound biopsies were employed to determine the efficacy of this therapeutic approach. The outcome of these infections was correctly predicted by the NAWD assay in 92.3% of the patients treated (p less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Liposomes-in-hydrogel delivery system with mupirocin: in vitro antibiofilm studies and in vivo evaluation in mice burn model.

    PubMed

    Hurler, Julia; Sørensen, Karen K; Fallarero, Adyary; Vuorela, Pia; Škalko-Basnet, Nataša

    2013-01-01

    Previously, we have proposed mupirocin-in-liposomes-in-hydrogel delivery system as advanced delivery system with the potential in treatment of burns. In the current studies, we evaluated the system for its cytotoxicity, ability to prevent biofilm formation, act on the mature biofilms, and finally determined its potential as wound treatment in in vivo mice burn model. The system was found to be nontoxic against HaCaT cells, that is, keratinocytes. It was safe for use and exhibited antibiofilm activity against S. aureus biofilms, although the activity was more significant against planktonic bacteria and prior to biofilm formation than against mature biofilms as shown in the resazurin and the crystal violet assays. An in vivo mice burn model was used to evaluate the biological potential of the system and the healing of burns observed over 28 days. The in vivo data suggest that the delivery system enhances wound healing and is equally potent as the marketed product of mupirocin. Histological examination showed no difference in the quality of the healed scar tissue, whereas the healing time for the new delivery system was shorter as compared to the marketed product. Further animal studies and development of more sophisticated in vivo model are needed for complete evaluation. PMID:24369533

  11. Liposomes-in-hydrogel delivery system with mupirocin: in vitro antibiofilm studies and in vivo evaluation in mice burn model.

    PubMed

    Hurler, Julia; Sørensen, Karen K; Fallarero, Adyary; Vuorela, Pia; Škalko-Basnet, Nataša

    2013-01-01

    Previously, we have proposed mupirocin-in-liposomes-in-hydrogel delivery system as advanced delivery system with the potential in treatment of burns. In the current studies, we evaluated the system for its cytotoxicity, ability to prevent biofilm formation, act on the mature biofilms, and finally determined its potential as wound treatment in in vivo mice burn model. The system was found to be nontoxic against HaCaT cells, that is, keratinocytes. It was safe for use and exhibited antibiofilm activity against S. aureus biofilms, although the activity was more significant against planktonic bacteria and prior to biofilm formation than against mature biofilms as shown in the resazurin and the crystal violet assays. An in vivo mice burn model was used to evaluate the biological potential of the system and the healing of burns observed over 28 days. The in vivo data suggest that the delivery system enhances wound healing and is equally potent as the marketed product of mupirocin. Histological examination showed no difference in the quality of the healed scar tissue, whereas the healing time for the new delivery system was shorter as compared to the marketed product. Further animal studies and development of more sophisticated in vivo model are needed for complete evaluation.

  12. Liposomes-in-Hydrogel Delivery System with Mupirocin: In Vitro Antibiofilm Studies and In Vivo Evaluation in Mice Burn Model

    PubMed Central

    Hurler, Julia; Sørensen, Karen K.; Vuorela, Pia; Škalko-Basnet, Nataša

    2013-01-01

    Previously, we have proposed mupirocin-in-liposomes-in-hydrogel delivery system as advanced delivery system with the potential in treatment of burns. In the current studies, we evaluated the system for its cytotoxicity, ability to prevent biofilm formation, act on the mature biofilms, and finally determined its potential as wound treatment in in vivo mice burn model. The system was found to be nontoxic against HaCaT cells, that is, keratinocytes. It was safe for use and exhibited antibiofilm activity against S. aureus biofilms, although the activity was more significant against planktonic bacteria and prior to biofilm formation than against mature biofilms as shown in the resazurin and the crystal violet assays. An in vivo mice burn model was used to evaluate the biological potential of the system and the healing of burns observed over 28 days. The in vivo data suggest that the delivery system enhances wound healing and is equally potent as the marketed product of mupirocin. Histological examination showed no difference in the quality of the healed scar tissue, whereas the healing time for the new delivery system was shorter as compared to the marketed product. Further animal studies and development of more sophisticated in vivo model are needed for complete evaluation. PMID:24369533

  13. Effects of sub-lethal concentrations of mupirocin on global transcription in Staphylococcus aureus 8325-4 and a model for the escape from inhibition.

    PubMed

    AlHoufie, Sari Talal S; Foster, Howard A

    2016-08-01

    Staphylococcus aureus is a major pathogen in both hospital and community settings, causing infections ranging from mild skin and wound infections to life-threatening systemic illness. Gene expression changes due to the stringent response have been studied in S. aureus using lethal concentrations of mupirocin, but no studies have investigated the effects of sub-lethal concentrations. S. aureus 8325-4 was exposed to sub-inhibitory concentrations of mupirocin. The production of ppGpp was assessed via HPLC and the effects on global transcription were studied by RNAseq (RNA sequencing) analysis. Growth inhibition had occurred after 1 h of treatment and metabolic analysis revealed that the stringent response alarmone ppGpp was present and GTP concentrations decreased. Transcriptome profiles showed that global transcriptional alterations were similar to those for S. aureus after treatment with lethal concentrations of mupirocin, including the repression of genes involved in transcription, translation and replication machineries. Furthermore, up-regulation of genes involved in stress responses, and amino acid biosynthesis and transport, as well as some virulence factor genes, was observed. However, ppGpp was not detectable after 12 or 24 h and cell growth had resumed, although some transcriptional changes remained. Sub-lethal concentrations of mupirocin induce the stringent response, but cells adapt and resume growth once ppGpp levels decrease.

  14. Evaluation of hospital palliative care teams: strengths and weaknesses of the before-after study design and strategies to improve it.

    PubMed

    Simon, S; Higginson, I J

    2009-01-01

    Hospital palliative care teams (HPCTs) are well established as multi-professional services to provide palliative care in an acute hospital setting and are increasing in number. However, there is still limited evaluation of them, in terms of efficacy and effectiveness. The gold standard method of evaluation is a randomised control trial, but because of methodological (e.g., randomisation), ethical and practical difficulties such trials are often not possible. HPCT is a complex intervention, and the specific situation in palliative care makes it challenging to evaluate (e.g., distress and cognitive impairment of patients). The quasi-experimental before-after study design has the advantage of enabling an experimental character without randomisation. But this has other weaknesses and is prone to bias, for example, temporal trends and selection bias. As for every study design, avoidance and minimisation of bias is important to improve validity. Therefore, strategies of selecting an appropriate control group or time series and applying valid outcomes and measurement tools help reducing bias and strengthen the methods. Special attention is needed to plan and define the design and applied method.

  15. Strengths and weaknesses in the supply of school food resulting from the procurement of family farm produce in a municipality in Brazil.

    PubMed

    Soares, Panmela; Martinelli, Suellen Secchi; Melgarejo, Leonardo; Davó-Blanes, Mari Carmen; Cavalli, Suzi Barletto

    2015-06-01

    The objective of this study was to assess compliance with school food programme recommendations for the procurement of family farm produce. This study consists of an exploratory descriptive study utilising a qualitative approach based on semistructured interviews with key informants in a municipality in the State of Santa Catarina in Brazil. Study participants were managers and staff of the school food programme and department of agriculture, and representatives of a farmers' organisation. The produce delivery and demand fulfilment stages of the procurement process were carried out in accordance with the recommendations. However, nonconformities occurred in the elaboration of the public call for proposals, elaboration of the sales proposal, and fulfilment of produce quality standards. It was observed that having a diverse range of suppliers and the exchange of produce by the cooperative with neighbouring municipalities helped to maintain a regular supply of produce. The elaboration of menus contributed to planning agricultural production. However, agricultural production was not mapped before elaborating the menus in this case study and an agricultural reform settlement was left out of the programme. A number of weaknesses in the programme were identified which need to be overcome in order to promote local family farming and improve the quality of school food in the municipality.

  16. Strength from weakness: conformational divergence between solid and solution states of substituted cyclitols facilitated by CH···O hydrogen bonding.

    PubMed

    Vibhute, Amol M; Sureshan, Kana M

    2014-06-01

    We have investigated the conformational preferences of a series of cyclitol derivatives, namely mono- and diesters of 1,2:5,6-di-O-isopropylidene-myo-inositol and 1,2:5,6-di-O-cyclohexylidene-myo-inositol, in both solid and solution states. The solid-state conformations were determined by single-crystal X-ray analysis. The solution-state conformations were determined by using NMR. The experimental (3)J(HH) values were applied in the Haasnoot-Altona equation to calculate the dihedral angle (ϕ) between the respective vicinal protons. By fixing the dihedral angle between different sets of vicinal protons, the molecules were energy-minimized by MM2 method to visualize their conformation in solution. As the solvent polarities can influence the conformational preference, we have determined the conformations of these molecules in various solvents of different polarities such as benzene-d6, chloroform-d, acetonitrile-d3, acetone-d6, methanol-d4, and DMSO-d6. All of the compounds adopted boat conformations in solution irrespective of the solvents, acyl groups, or alkylidene protecting groups. This conformation places H6 and O3 of the cyclitol ring in proximity, such that an intramolecular CH···O hydrogen bond between them stabilizes this otherwise unstable conformation. However, in the solid state, several intermolecular CH···O hydrogen bonds force these molecules to adopt the chair conformation. This study uncovers the role of weak noncovalent interactions in influencing the molecular conformations differentially in different states.

  17. Characterizing the Long-Term PM2.5 Concentration-Response Function: Comparing the Strengths and Weaknesses of Research Synthesis Approaches.

    PubMed

    Fann, Neal; Gilmore, Elisabeth A; Walker, Katherine

    2016-09-01

    The magnitude, shape, and degree of certainty in the association between long-term population exposure to ambient fine particulate matter (PM2.5 ) and the risk of premature death is one of the most intensely studied issues in environmental health. For regulatory risk analysis, this relationship is described quantitatively by a concentration-response (C-R) function that relates exposure to ambient concentrations with the risk of premature mortality. Four data synthesis techniques develop the basis for, and derive, this function: systematic review, expert judgment elicitation, quantitative meta-analysis, and integrated exposure-response (IER) assessment. As part of an academic workshop aiming to guide the use of research synthesis approaches, we developed criteria with which to evaluate and select among the approaches for their ability to inform policy choices. These criteria include the quality and extent of scientific support for the method, its transparency and verifiability, its suitability to the policy problem, and the time and resources required for its application. We find that these research methods are both complementary and interdependent. A systematic review of the multidisciplinary evidence is a starting point for all methods, providing the broad conceptual basis for the nature, plausibility, and strength of the associations between PM exposure and adverse health effects. Further, for a data-rich application like PM2.5 and premature mortality, all three quantitative approaches can produce estimates that are suitable for regulatory and benefit analysis. However, when fewer data are available, more resource-intensive approaches such as expert elicitation may be more important for understanding what scientists know, where they agree or disagree, and what they believe to be the most important areas of uncertainty. Whether implicitly or explicitly, all require considerable judgment by scientists. Finding ways for all these methods to acknowledge

  18. Effect of the pH and the ionic strength on overloaded band profiles of weak bases onto neutral and charged surface hybrid stationary phases in reversed-phase liquid chromatography.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2013-03-22

    This work reports on the effects of the solution pH and its ionic strength on the overloaded band profiles and the parameters of the adsorption isotherms of nortriptylinium hydrochloride on the bridge ethylene hybrid (BEH) and the charged surface hybrid (CSH) C18-bonded columns. The mobile phases used were mixtures of acetonitrile and water buffered with hydrogenophosphate, formate, acetate, and dihydrogenophosphate buffers. The results show that the adsorption behavior of this protonated base onto the BEH-C18 column depends barely on the mobile phase pH and is slightly affected by its ionic strength. From both physical and statistical viewpoints, the Linear-Langmuir model is the most relevant adsorption isotherm. According to the inverse method of chromatography, this model is consistent with weak dispersive interactions taking place onto the C18-bonded chains and some strong ion-dipole interactions with residual silanols. In contrast, adsorption on the CSH-C18 column depends on the applied W(S)pH, e.g., on the degree of ionization of the amine groups tethered to the CSH surface. For W(S)pH<3, the electrostatically modified Langmuir model (EML) is acceptable because analyte molecules cannot access and interact with any active sites due to the electrostatic repulsion by the positively charged adsorbent surface. At W(S)pH>7.0, the Linear-bi-Langmuir model describes best the weak adsorption of the protonated base molecules onto the C18 chains and their strong adsorption onto the residual silanols and neutral amine groups. PMID:23415137

  19. Weak bond screening system

    NASA Astrophysics Data System (ADS)

    Chuang, S. Y.; Chang, F. H.; Bell, J. R.

    Consideration is given to the development of a weak bond screening system which is based on the utilization of a high power ultrasonic (HPU) technique. The instrumentation of the prototype bond strength screening system is described, and the adhesively bonded specimens used in the system developmental effort are detailed. Test results obtained from these specimens are presented in terms of bond strength and level of high power ultrasound irradiation. The following observations were made: (1) for Al/Al specimens, 2.6 sec of HPU irradiation will screen weak bond conditions due to improper preparation of bonding surfaces; (2) for composite/composite specimens, 2.0 sec of HPU irradiation will disrupt weak bonds due to under-cured conditions; (3) for Al honeycomb core with composite skin structure, 3.5 sec of HPU irradiation will disrupt weak bonds due to bad adhesive or oils contamination of bonding surfaces; and (4) for Nomex honeycomb with Al skin structure, 1.3 sec of HPU irradiation will disrupt weak bonds due to bad adhesive.

  20. The interRAI Acute Care instrument incorporated in an eHealth system for standardized and web-based geriatric assessment: strengths, weaknesses, opportunities and threats in the acute hospital setting

    PubMed Central

    2013-01-01

    Background The interRAI Acute Care instrument is a multidimensional geriatric assessment system intended to determine a hospitalized older persons’ medical, psychosocial and functional capacity and needs. Its objective is to develop an overall plan for treatment and long-term follow-up based on a common set of standardized items that can be used in various care settings. A Belgian web-based software system (BelRAI-software) was developed to enable clinicians to interpret the output and to communicate the patients’ data across wards and care organizations. The purpose of the study is to evaluate the (dis)advantages of the implementation of the interRAI Acute Care instrument as a comprehensive geriatric assessment instrument in an acute hospital context. Methods In a cross-sectional multicenter study on four geriatric wards in three acute hospitals, trained clinical staff (nurses, occupational therapists, social workers, and geriatricians) assessed 410 inpatients in routine clinical practice. The BelRAI-system was evaluated by focus groups, observations, and questionnaires. The Strengths, Weaknesses, Opportunities and Threats were mapped (SWOT-analysis) and validated by the participants. Results The primary strengths of the BelRAI-system were a structured overview of the patients’ condition early after admission and the promotion of multidisciplinary assessment. Our study was a first attempt to transfer standardized data between home care organizations, nursing homes and hospitals and a way to centralize medical, allied health professionals and nursing data. With the BelRAI-software, privacy of data is guaranteed. Weaknesses are the time-consuming character of the process and the overlap with other assessment instruments or (electronic) registration forms. There is room for improving the user-friendliness and the efficiency of the software, which needs hospital-specific adaptations. Opportunities are a timely and systematic problem detection and continuity of

  1. Mutational analysis reveals that all tailoring region genes are required for production of polyketide antibiotic mupirocin by pseudomonas fluorescens: pseudomonic acid B biosynthesis precedes pseudomonic acid A.

    PubMed

    Hothersall, Joanne; Wu, Ji'en; Rahman, Ayesha S; Shields, Jennifer A; Haddock, James; Johnson, Nicola; Cooper, Sian M; Stephens, Elton R; Cox, Russell J; Crosby, John; Willis, Christine L; Simpson, Thomas J; Thomas, Christopher M

    2007-05-25

    The Pseudomonas fluorescens mupirocin biosynthetic cluster encodes six proteins involved in polyketide biosynthesis and 26 single polypeptides proposed to perform largely tailoring functions. In-frame deletions in the tailoring open reading frames demonstrated that all are required for mupirocin production. A bidirectional promoter region was identified between mupF, which runs counter to other open reading frames and its immediate neighbor macpC, implying the 74-kb cluster consists of two transcriptional units. mupD/E and mupJ/K must be cotranscribed as pairs for normal function implying co-assembly during translation. MupJ and K belong to a widely distributed enzyme pair implicated, with MupH, in methyl addition. Deletion of mupF, a putative ketoreductase, produced a mupirocin analogue with a C-7 ketone. Deletion of mupC, a putative dienoyl CoA reductase, generated an analogue whose structure indicated that MupC is also implicated in control of the oxidation state around the tetrahydropyran ring of monic acid. Double mutants with DeltamupC and DeltamupO, DeltamupU, DeltamupV, or DeltamacpE produced pseudomonic acid B but not pseudomonic acid A, as do the mupO, U, V, and macpE mutants, indicating that MupC must work after MupO, U, and V.

  2. The Zirconia Ceramic: Strengths and Weaknesses

    PubMed Central

    Daou, Elie E.

    2014-01-01

    Metal ceramic restorations were considered the gold standard as reliable materials. Increasing demand for esthetics supported the commercialization of new metal free restorations. A growing demand is rising for zirconia prostheses. Peer-reviewed articles published till July 2013 were identified through a Medline (Pubmed and Elsevier). Emphasizing was made on zirconia properties and applications. Zirconia materials are able to withstand posterior physiologic loads. Although zirconia cores are considered as reliable materials, these restorations are not problem free. PMID:24851138

  3. Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.

    1957-06-01

    Experimental results on the non-conservation of parity and charge conservation in weak interactions are reviewed. The two-component theory of the neutrino is discussed. Lepton reactions are examined under the assumption of the law of conservation of leptons and that the neutrino is described by a two- component theory. From the results of this examination, the universal Fermi interactions are analyzed. Although reactions involving the neutrino can be described, the same is not true of reactions which do not involve the lepton, as the discussion of the decay of K mesons and hyperons shows. The question of the invariance of time reversal is next examined. (J.S.R.)

  4. Quantum discord with weak measurements

    SciTech Connect

    Singh, Uttam Pati, Arun Kumar

    2014-04-15

    Weak measurements cause small change to quantum states, thereby opening up the possibility of new ways of manipulating and controlling quantum systems. We ask, can weak measurements reveal more quantum correlation in a composite quantum state? We prove that the weak measurement induced quantum discord, called as the “super quantum discord”, is always larger than the quantum discord captured by the strong measurement. Moreover, we prove the monotonicity of the super quantum discord as a function of the measurement strength and in the limit of strong projective measurement the super quantum discord becomes the normal quantum discord. We find that unlike the normal discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. Our results provide new insights on the nature of quantum correlation and suggest that the notion of quantum correlation is not only observer dependent but also depends on how weakly one perturbs the composite system. We illustrate the key results for pure as well as mixed entangled states. -- Highlights: •Introduced the role of weak measurements in quantifying quantum correlation. •We have introduced the notion of the super quantum discord (SQD). •For pure entangled state, we show that the SQD exceeds the entanglement entropy. •This shows that quantum correlation depends not only on observer but also on measurement strength.

  5. Spin effects in the weak interaction

    SciTech Connect

    Freedman, S.J. Chicago Univ., IL . Dept. of Physics Chicago Univ., IL . Enrico Fermi Inst.)

    1990-01-01

    Modern experiments investigating the beta decay of the neutron and light nuclei are still providing important constraints on the theory of the weak interaction. Beta decay experiments are yielding more precise values for allowed and induced weak coupling constants and putting constraints on possible extensions to the standard electroweak model. Here we emphasize the implications of recent experiments to pin down the strengths of the weak vector and axial vector couplings of the nucleon.

  6. Weak scale supersymmetry

    SciTech Connect

    Hall, L.J. California Univ., Berkeley, CA . Dept. of Physics)

    1990-11-12

    An introduction to the ideas and current state of weak scale supersymmetry is given. It is shown that LEP data on Z decays has already excluded two of the most elegant models of weak scale supersymmetry. 14 refs.

  7. Frequency of biocide-resistant genes and susceptibility to chlorhexidine in high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA).

    PubMed

    Liu, Qingzhong; Zhao, Huanqiang; Han, Lizhong; Shu, Wen; Wu, Qiong; Ni, Yuxing

    2015-08-01

    The aim of this study was to determine the prevalence of biocide-resistant determinants and the susceptibility to chlorhexidine in high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA). Fifty-three MuH MRSA isolates were analyzed for plasmid-borne genes (qacA/B, smr, qacG, qacH, and qacJ) by polymerase chain reaction (PCR); for chromosome-mediated genes (norA, norB, norC, mepA, mdeA, sepA, and sdrM) by PCR and quantitative reverse transcription-PCR (qRT-PCR); and for susceptibility to chlorhexidine by MIC and minimum bactericidal concentration (MBC). Furthermore, disinfectant efficacy was tested in the presence of 3.0% bovine serum albumin (BSA) in MBC detection. The plasmid-borne genes qacA/B (83.0%) and smr (77.4%) and overexpressions of chromosome-mediated genes norA (49.0%) and norB (28.8%) were predominantly found in isolates studied, and 90.6% of the isolates revealed tolerance to chlorhexidine. In the presence of BSA, the average MBC of chlorhexidine for these isolates rose to 256 μg/mL. Altogether, our results suggest that surveillance of sensitivity to biocides among MuH MRSA isolates is essential for hospital infection control.

  8. Development of a selective culture medium for bifidobacteria, Raffinose-Propionate Lithium Mupirocin (RP-MUP) and assessment of its usage with Petrifilm™ Aerobic Count plates.

    PubMed

    Miranda, Rodrigo Otávio; de Carvalho, Antonio Fernandes; Nero, Luís Augusto

    2014-05-01

    This study aimed to develop a selective culture media to enumerate bifidobacteria in fermented milk and to assess this medium when used with Petrifilm™ AC plates. For this purpose, Bifidobacterium spp., Lactobacillus spp. and Streptococcus thermophilus strains were tested to verify their fermentation patterns for different carbohydrates. All bifidobacteria strains were able to use raffinose. Based on these characteristic, a selective culture medium was proposed (Raffinose-Propionate Lithium Mupirocin, RP-MUP), used with Petrifilm™ AC plates, and was used to enumerate bifidobacteria in fermented milk. RP-MUP performance was assessed by comparing the results with this medium to reference protocols and culture media for bifidobacteria enumeration. RP-MUP, whether used or not with Petrifilm™ AC, presented similar performance to TOS-MUP (ISO 29981), with no significant differences between the mean bifidobacteria counts (p < 0.05) and with high correlation indices (r = 0.99, p < 0.05). As an advantage, reliable results were obtained after just 48 h of incubation when RP-MUP was used with Petrifilm™ AC, instead of the 72 h described in the ISO 29981 protocol.

  9. Shoulder weakness in professional baseball pitchers.

    PubMed

    Magnusson, S P; Gleim, G W; Nicholas, J A

    1994-01-01

    The purposes of this study were to: 1) compare shoulder range of motion and strength in professional baseball pitchers (N = 47) compared with age-matched controls (N = 16), and 2) examine the relationship of injury history to strength and range of motion. Based on injury history pitchers were categorized as: 1) none (N = 26), 2) injury requiring conservative intervention (N = 9), or 3) injury requiring surgical intervention (N = 12). Range of motion was measured for internal rotation (IROM) and external rotation (EROM). Eccentric strength was measured by hand-held dynamometer for internal rotation (IR), external rotation (ER), abduction (ABD), and supraspinatus muscle (SUP) strength. Injury history had no effect on strength and range of motion. Dominant EROM was greater in pitchers, P < 0.0001, and controls, P < 0.05, with pitchers having greater EROM motion bilaterally, P < 0.0001. Pitchers were weaker in SUP on the dominant vs nondominant side, P < 0.0001, and on the dominant side for weight adjusted ER, ABD, P < 0.01, and SUP, P < 0.0001, compared with controls. In conclusion, dominance and pitching resulted in soft tissue adaptation. Pitchers displayed weakness in three of four tests by comparison with controls, suggesting that the demands of pitching are insufficient to produce eccentric strength gains and may in fact lead to weakness. Dominant-side SUP weakness in pitchers may reflect subclinical pathology or chronic fatigue.

  10. Postselected weak measurement beyond the weak value

    SciTech Connect

    Geszti, Tamas

    2010-04-15

    Closed expressions are derived for the quantum measurement statistics of pre- and postselected Gaussian particle beams. The weakness of the preselection step is shown to compete with the nonorthogonality of postselection in a transparent way. The approach is shown to be useful in analyzing postselection-based signal amplification, allowing measurements to be extended far beyond the range of validity of the well-known Aharonov-Albert-Vaidman limit. Additionally, the present treatment connects postselected weak measurement to the topic of phase-contrast microscopy.

  11. Distribution of muscle weakness of central and peripheral origin.

    PubMed

    Thijs, R D; Notermans, N C; Wokke, J H; van der Graaf, Y; van Gijn, J

    1998-11-01

    According to the established clinical tradition about the distribution of weakness, the ratios of flexor/extensor strength of patients with upper motor neuron lesions are expected to be relatively high for the elbow and wrist and low for the knee. To assess the diagnostic value of these patterns of weakness, muscle strength of 70 patients with limb weakness of central or peripheral origin was measured with a hand held dynamometer. The ratios of flexor/extensor strength at the knee, elbow, and wrist did not differ significantly between patients with central or peripheral origin of muscle weakness. The examination of tendon jerks proved to be of more value as a localising feature. The traditional notion about the distribution of weakness in upper motor neuron lesions may be explained by an intrinsically greater strength in antigravity muscles, together with the effects of hypertonia. PMID:9810962

  12. Aperiodic Weak Topological Superconductors

    NASA Astrophysics Data System (ADS)

    Fulga, I. C.; Pikulin, D. I.; Loring, T. A.

    2016-06-01

    Weak topological phases are usually described in terms of protection by the lattice translation symmetry. Their characterization explicitly relies on periodicity since weak invariants are expressed in terms of the momentum-space torus. We prove the compatibility of weak topological superconductors with aperiodic systems, such as quasicrystals. We go beyond usual descriptions of weak topological phases and introduce a novel, real-space formulation of the weak invariant, based on the Clifford pseudospectrum. A nontrivial value of this index implies a nontrivial bulk phase, which is robust against disorder and hosts localized zero-energy modes at the edge. Our recipe for determining the weak invariant is directly applicable to any finite-sized system, including disordered lattice models. This direct method enables a quantitative analysis of the level of disorder the topological protection can withstand.

  13. Aperiodic Weak Topological Superconductors.

    PubMed

    Fulga, I C; Pikulin, D I; Loring, T A

    2016-06-24

    Weak topological phases are usually described in terms of protection by the lattice translation symmetry. Their characterization explicitly relies on periodicity since weak invariants are expressed in terms of the momentum-space torus. We prove the compatibility of weak topological superconductors with aperiodic systems, such as quasicrystals. We go beyond usual descriptions of weak topological phases and introduce a novel, real-space formulation of the weak invariant, based on the Clifford pseudospectrum. A nontrivial value of this index implies a nontrivial bulk phase, which is robust against disorder and hosts localized zero-energy modes at the edge. Our recipe for determining the weak invariant is directly applicable to any finite-sized system, including disordered lattice models. This direct method enables a quantitative analysis of the level of disorder the topological protection can withstand. PMID:27391744

  14. Apple Strength Issues

    SciTech Connect

    Syn, C

    2009-12-22

    Strength of the apple parts has been noticed to decrease, especially those installed by the new induction heating system since the LEP campaign started. Fig. 1 shows the ultimate tensile strength (UTS), yield strength (YS), and elongation of the installed or installation-simulated apples on various systems. One can clearly see the mean values of UTS and YS of the post-LEP parts decreased by about 8 ksi and 6 ksi respectively from those of the pre-LEP parts. The slight increase in elongation seen in Fig.1 can be understood from the weak inverse relationship between the strength and elongation in metals. Fig.2 shows the weak correlation between the YS and elongation of the parts listed in Fig. 1. Strength data listed in Figure 1 were re-plotted as histograms in Figs. 3 and 4. Figs. 3a and 4a show histograms of all UTS and YS data. Figs. 3b and 4b shows histograms of pre-LEP data and Figs. 3c and 4c of post-LEP data. Data on statistical scatter of tensile strengths have been rarely published by material suppliers. Instead, only the minimum 'guaranteed' strength data are typically presented. An example of strength distribution of aluminum 7075-T6 sheet material, listed in Fig. 5, show that its scatter width of both UTS and YS for a single sheet can be about 6 ksi and for multi-lot scatter can be as large as 11 ksi even though the sheets have been produced through well-controlled manufacturing process. By approximating the histograms shown in Figs. 3 and 4 by a Gaussian or similar type of distribution curves, one can plausibly see the strength reductions in the later or more recent apples. The pre-LEP data in Figs. 3b and 4b show wider scatter than the post-LEP data in Figs. 3c and 4c and seem to follow the binomial distribution of strength indicating that the apples might have been made from two different lots of material, either from two different vendors or from two different melts of perhaps slightly different chemical composition by a single vendor. The post

  15. Many-body chaos at weak coupling

    NASA Astrophysics Data System (ADS)

    Stanford, Douglas

    2016-10-01

    The strength of chaos in large N quantum systems can be quantified using λ L , the rate of growth of certain out-of-time-order four point functions. We calculate λ L to leading order in a weakly coupled matrix Φ4 theory by numerically diagonalizing a ladder kernel. The computation reduces to an essentially classical problem.

  16. Experimental noiseless linear amplification using weak measurements

    NASA Astrophysics Data System (ADS)

    Ho, Joseph; Boston, Allen; Palsson, Matthew; Pryde, Geoff

    2016-09-01

    The viability of quantum communication schemes rely on sending quantum states of light over long distances. However, transmission loss can degrade the signal strength, adding noise. Heralded noiseless amplification of a quantum signal can provide a solution by enabling longer direct transmission distances and by enabling entanglement distillation. The central idea of heralded noiseless amplification—a conditional modification of the probability distribution over photon number of an optical quantum state—is suggestive of a parallel with weak measurement: in a weak measurement, learning partial information about an observable leads to a conditional back-action of a commensurate size. Here we experimentally investigate the application of weak, or variable-strength, measurements to the task of heralded amplification, by using a quantum logic gate to weakly couple a small single-optical-mode quantum state (the signal) to an ancilla photon (the meter). The weak measurement is carried out by choosing the measurement basis of the meter photon and, by conditioning on the meter outcomes, the signal is amplified. We characterise the gain of the amplifier as a function of the measurement strength, and use interferometric methods to show that the operation preserves the coherence of the signal.

  17. Strength Testing.

    ERIC Educational Resources Information Center

    Londeree, Ben R.

    1981-01-01

    Postural deviations resulting from strength and flexibility imbalances include swayback, scoliosis, and rounded shoulders. Screening tests are one method for identifying strength problems. Tests for the evaluation of postural problems are described, and exercises are presented for the strengthening of muscles. (JN)

  18. Multidrug-resistant clones of community-associated meticillin-resistant Staphylococcus aureus isolated from Chinese children and the resistance genes to clindamycin and mupirocin.

    PubMed

    Wang, Lijuan; Liu, Yingchao; Yang, Yonghong; Huang, Guoying; Wang, Chuanqing; Deng, Li; Zheng, Yuejie; Fu, Zhou; Li, Changcong; Shang, Yunxiao; Zhao, Changan; Sun, Mingjiao; Li, Xiangmei; Yu, Sangjie; Yao, Kaihu; Shen, Xuzhuang

    2012-09-01

    This study aimed to correlate the multidrug resistance (MDR) and sequence type (ST) clones of community-associated (CA) meticillin-resistant Staphylococcus aureus (MRSA) to identify the genes responsible for clindamycin and mupirocin resistance in S. aureus isolates from paediatric hospitals in mainland China. A total of 435 S. aureus isolates were collected. Compared with CA meticillin-susceptible S. aureus (MSSA), the resistance rates of CA-MRSA to ciprofloxacin, chloramphenicol, gentamicin and tetracycline were higher (19.0 vs 2.6 %, P<0.001; 14.7 vs 3.1 %, P<0.001; 14.7 vs 3.1 %, P<0.01; and 46.0 vs 13.3 %, P<0.001, respectively). Compared with hospital-associated (HA)-MRSA, the resistance rates of CA-MRSA to ciprofloxacin, gentamicin, rifampicin, tetracycline and trimethoprim-sulfamethoxazole were lower (19 vs 94.8 %, P<0.001; 14.7 vs 84.4 %, P<0.001; 5.5 vs 88.3 %, P<0.001; 46 vs 94.8 %, P<0.001; and 1.8 vs 9.1 %, P<0.01, respectively). The resistance rates of CA-MRSA, HA-MRSA and CA-MSSA to clindamycin (92.0, 77.9 and 64.1 %, respectively) and erythromycin (85.9, 77.9 and 63.1 %, respectively) were high. The MDR rates (resistance to three or more non-β-lactams) were 49.6, 100 and 14 % in the CA-MRSA, HA-MRSA and CA-MSSA isolates, respectively. Five of seven ST clones in the CA-MRSA isolates, namely ST59, ST338, ST45, ST910 and ST965, had MDR rates of >50 % (67.9, 87.5, 100, 50 and 83.3 %, respectively). The constitutive phenotype of macrolide-lincosamide-streptogramin B (MLS(B)) resistance (69 %) and the ermB gene (38.1 %) predominated among the MLS(B)-resistant CA S. aureus strains. The resistance rate to mupirocin was 2.3 % and plasmids carrying the mupA gene varied in size between 23 and 54.2 kb in six strains with high-level resistance as determined by Southern blot analysis. The present study showed that resistance to non-β-lactams, especially to clindamycin, is high in CA-MRSA isolates from Chinese children and that

  19. Weak measure expansive flows

    NASA Astrophysics Data System (ADS)

    Lee, Keonhee; Oh, Jumi

    2016-01-01

    A notion of measure expansivity for flows was introduced by Carrasco-Olivera and Morales in [3] as a generalization of expansivity, and they proved that there were no measure expansive flows on closed surfaces. In this paper we introduce a concept of weak measure expansivity for flows which is really weaker than that of measure expansivity, and show that there is a weak measure expansive flow on a closed surface. Moreover we show that any C1 stably weak measure expansive flow on a C∞ closed manifold M is Ω-stable, and any C1 stably measure expansive flow on M satisfies both Axiom A and the quasi-transversality condition.

  20. Coupling-deformed pointer observables and weak values

    NASA Astrophysics Data System (ADS)

    Zhang, Yu-Xiang; Wu, Shengjun; Chen, Zeng-Bing

    2016-03-01

    While the novel applications of weak values have recently attracted wide attention, weak measurement, the usual way to extract weak values, suffers from risky approximations and severe quantum noises. In this paper, we show that the weak-value information can be obtained exactly in strong measurement with postselections, via measuring the coupling-deformed pointer observables, i.e., the observables selected according to the coupling strength. With this approach, we keep all the advantages claimed by weak-measurement schemes and at the same time solve some widely criticized problems thereof, such as the questionable universality, systematical bias, and drastic inefficiency.

  1. History of Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.

    1970-07-01

    While the phenomenon of beta-decay was discovered near the end of the last century, the notion that the weak interaction forms a separate field of physical forces evolved rather gradually. This became clear only after the experimental discoveries of other weak reactions such as muon-decay, muon-capture, etc., and the theoretical observation that all these reactions can be described by approximately the same coupling constant, thus giving rise to the notion of a universal weak interaction. Only then did one slowly recognize that the weak interaction force forms an independent field, perhaps on the same footing as the gravitational force, the electromagnetic force, and the strong nuclear and sub-nuclear forces.

  2. Overview of inhalation exposure techniques: strengths and weaknesses.

    PubMed

    Pauluhn, Jürgen

    2005-07-01

    The vast majority of toxicity studies and risk evaluations deal with single chemicals. Due to the growing interest in potential human health risks originating from exposure to environmental pollutants or lifestyle-related complex chemical mixtures, well thought-out tailor-made mechanistic inhalation toxicity studies have been performed. In contrast to the complex mixtures potentially encountered from hazardous waste sites, drinking water disinfection by-products, natural flavoring complexes or the cumulative intake of food additives and pesticide residues, the scientific evaluation of complex airborne mixtures, such as acid aerosols, atmospheres produced by combustion or thermolysis, e.g. residual oil fly ash (ROFA), diesel and gasoline exhaust, and tobacco smoke, or volatile organic chemicals (VOCs) in residential areas, to mention but a few, is a daunting challenge for experimental toxicologists. These challenges include the controlled in situ generation of exposure atmospheres, the compositions of which are often process-determined and metastable. This means that volatile agents may partition with liquid aerosols or be adsorbed onto surfaces of solid aerosols. Similarly, the nature and composition of test atmospheres might change continuously through oxidation and aging of constituents or coagulation of particles. This, in turn, poses additional challenges to the analytical characterization of such complex test atmospheres, including the identification of potential experimental artifacts. Accordingly, highly standardized and controlled inhalation studies are required for hazard identification of complex mixtures and the results of inhalation studies have to be analyzed judiciously due to the great number of experimental variables. These variables may be related to technical issues or to the specific features of the animal model. Although inhalation exposure of animals mimics human exposure best, not all results obtained under such rigorous test conditions might necessarily also occur under real-life exposure conditions. In addition, to simulate experimentally specific use or exposure patterns may impose a particular challenge to traditional approaches in terms of relevant exposure metrics and the analytes chosen to characterize exposure atmospheres. This paper addresses major developments in the discipline of inhalation toxicology with particular emphasis on the state-of-the-art testing of complex mixtures.

  3. Cognitive Strengths and Weaknesses Associated with Prader-Willi Syndrome.

    ERIC Educational Resources Information Center

    Conners, Frances A.; Rosenquist, Celia J.; Atwell, Julie A.; Klinger, Laura Grofer

    2000-01-01

    Nine adults with Prader-Willi syndrome (PWS) and nine age- and IQ-matched adults with PWS completed standardized tests of long-term and short-term memory, visual and auditory processing, and reading and mathematics achievement. Contrary to previous findings, long-term memory in PWS subjects was strong relative to IQ and there was no evidence that…

  4. Finnish Vocational Education and Training in Comparison: Strengths and Weaknesses

    ERIC Educational Resources Information Center

    Virolainen, Maarit; Stenström, Marja-Leena

    2014-01-01

    The study investigates how the Finnish model of providing initial vocational education and training (IVET) has succeeded in terms of enhancing educational progress and employability. A relatively high level of participation in IVET makes the Finnish model distinctive from those of three other Nordic countries: Denmark, Norway and Sweden. All four…

  5. The Strengths and Weaknesses of ISO 9000 in Vocational Education

    ERIC Educational Resources Information Center

    Bevans-Gonzales, Theresa L.; Nair, Ajay T.

    2004-01-01

    ISO 9000 is a set of quality standards that assists an organization to identify, correct and prevent errors, and to promote continual improvement. Educational institutions worldwide are implementing ISO 9000 as they face increasing external pressure to maintain accountability for funding. Similar to other countries, in the United States vocational…

  6. Nonexperimental Research: Strengths, Weaknesses and Issues of Precision

    ERIC Educational Resources Information Center

    Reio, Thomas G., Jr.

    2016-01-01

    Purpose: Nonexperimental research, defined as any kind of quantitative or qualitative research that is not an experiment, is the predominate kind of research design used in the social sciences. How to unambiguously and correctly present the results of nonexperimental research, however, remains decidedly unclear and possibly detrimental to applied…

  7. Heterogeneous, weakly coupled map lattices

    NASA Astrophysics Data System (ADS)

    Sotelo Herrera, M.a. Dolores; San Martín, Jesús; Porter, Mason A.

    2016-07-01

    Coupled map lattices (CMLs) are often used to study emergent phenomena in nature. It is typically assumed (unrealistically) that each component is described by the same map, and it is important to relax this assumption. In this paper, we characterize periodic orbits and the laminar regime of type-I intermittency in heterogeneous weakly coupled map lattices (HWCMLs). We show that the period of a cycle in an HWCML is preserved for arbitrarily small coupling strengths even when an associated uncoupled oscillator would experience a period-doubling cascade. Our results characterize periodic orbits both near and far from saddle-node bifurcations, and we thereby provide a key step for examining the bifurcation structure of heterogeneous CMLs.

  8. Strength nutrition.

    PubMed

    Volek, Jeff S

    2003-08-01

    Muscle strength is determined by muscle size and factors related to neural recruitment. Resistance training is a potent stimulus for increasing muscle size and strength. These increases are, to a large extent, influenced and mediated by changes in hormones that regulate important events during the recovery process following exercise. Provision of nutrients in the appropriate amounts and at the appropriate times is necessary to optimize the recovery process. This review discusses the results of research that has examined the potential for nutrition and dietary supplements to impact the acute response to resistance exercise and chronic adaptations to resistance training. To date, the most promising strategies to augment gains in muscle size and strength appear to be consumption of protein-carbohydrate calories before and after resistance exercise, and creatine supplementation.

  9. Weak shock reflection

    NASA Astrophysics Data System (ADS)

    Hunter, John K.; Brio, Moysey

    2000-05-01

    We present numerical solutions of a two-dimensional inviscid Burgers equation which provides an asymptotic description of the Mach reflection of weak shocks. In our numerical solutions, the incident, reflected, and Mach shocks meet at a triple point, and there is a supersonic patch behind the triple point, as proposed by Guderley for steady weak-shock reflection. A theoretical analysis indicates that there is an expansion fan at the triple point, in addition to the three shocks. The supersonic patch is extremely small, and this work is the first time it has been resolved.

  10. A Review of the Theory and Research Underlying the StrengthsQuest Program for Students. The Quest for Strengths

    ERIC Educational Resources Information Center

    Hodges, Timothy D.; Harter, James K.

    2005-01-01

    StrengthsQuest is a student program that focuses on strengths rather than weaknesses. It is intended to lead students to discover their natural talents and gain unique and valuable insights into how to develop such talents into strengths--strengths that equip them to succeed and to make important decisions that enable them to balance the demands…

  11. Weak interactions, omnivory and emergent food-web properties.

    PubMed Central

    Emmerson, Mark; Yearsley, Jon M.

    2004-01-01

    Empirical studies have shown that, in real ecosystems, species-interaction strengths are generally skewed in their distribution towards weak interactions. Some theoretical work also suggests that weak interactions, especially in omnivorous links, are important for the local stability of a community at equilibrium. However, the majority of theoretical studies use uniform distributions of interaction strengths to generate artificial communities for study. We investigate the effects of the underlying interaction-strength distribution upon the return time, permanence and feasibility of simple Lotka-Volterra equilibrium communities. We show that a skew towards weak interactions promotes local and global stability only when omnivory is present. It is found that skewed interaction strengths are an emergent property of stable omnivorous communities, and that this skew towards weak interactions creates a dynamic constraint maintaining omnivory. Omnivory is more likely to occur when omnivorous interactions are skewed towards weak interactions. However, a skew towards weak interactions increases the return time to equilibrium, delays the recovery of ecosystems and hence decreases the stability of a community. When no skew is imposed, the set of stable omnivorous communities shows an emergent distribution of skewed interaction strengths. Our results apply to both local and global concepts of stability and are robust to the definition of a feasible community. These results are discussed in the light of empirical data and other theoretical studies, in conjunction with their broader implications for community assembly. PMID:15101699

  12. In praise of weakness

    NASA Astrophysics Data System (ADS)

    Steinberg, Aephraim; Feizpour, Amir; Rozema; Mahler; Hayat

    2013-03-01

    Quantum physics is being transformed by a radical new conceptual and experimental approach known as weak measurement that can do everything from tackling basic quantum mysteries to mapping the trajectories of photons in a Young's double-slit experiment. Aephraim Steinberg, Amir Feizpour, Lee Rozema, Dylan Mahler and Alex Hayat unveil the power of this new technique.

  13. Hypernuclear Weak Decays

    NASA Astrophysics Data System (ADS)

    Itonaga, K.; Motoba, T.

    The recent theoretical studies of Lambda-hypernuclear weak decaysof the nonmesonic and pi-mesonic ones are developed with the aim to disclose the link between the experimental decay observables and the underlying basic weak decay interactions and the weak decay mechanisms. The expressions of the nonmesonic decay rates Gamma_{nm} and the decay asymmetry parameter alpha_1 of protons from the polarized hypernuclei are presented in the shell model framework. We then introduce the meson theoretical Lambda N -> NN interactions which include the one-meson exchanges, the correlated-2pi exchanges, and the chiral-pair-meson exchanges. The features of meson exchange potentials and their roles on the nonmesonic decays are discussed. With the adoption of the pi + 2pi/rho + 2pi/sigma + omega + K + rhopi/a_1 + sigmapi/a_1 exchange potentials, we have carried out the systematic calculations of the nonmesonic decay observables for light-to-heavy hypernuclei. The present model can account for the available experimental data of the decay rates, Gamma_n/Gamma_p ratios, and the intrinsic asymmetry parameters alpha_Lambda (alpha_Lambda is related to alpha_1) of emitted protons well and consistently within the error bars. The hypernuclear lifetimes are evaluated by converting the total weak decay rates Gamma_{tot} = Gamma_pi + Gamma_{nm} to tau, which exhibit saturation property for the hypernuclear mass A ≥ 30 and agree grossly well with experimental data for the mass range from light to heavy hypernuclei except for the very light ones. Future extensions of the model and the remaining problems are also mentioned. The pi-mesonic weak processes are briefly surveyed, and the calculations and predictions are compared and confirmed by the recent high precision FINUDA pi-mesonic decay data. This shows that the theoretical basis seems to be firmly grounded.

  14. Weak Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Pires, Sandrine; Starck, Jean-Luc; Leonard, Adrienne; Réfrégier, Alexandre

    2012-03-01

    This chapter reviews the data mining methods recently developed to solve standard data problems in weak gravitational lensing. We detail the different steps of the weak lensing data analysis along with the different techniques dedicated to these applications. An overview of the different techniques currently used will be given along with future prospects. Until about 30 years ago, astronomers thought that the Universe was composed almost entirely of ordinary matter: protons, neutrons, electrons, and atoms. The field of weak lensing has been motivated by the observations made in the last decades showing that visible matter represents only about 4-5% of the Universe (see Figure 14.1). Currently, the majority of the Universe is thought to be dark, that is, does not emit electromagnetic radiation. The Universe is thought to be mostly composed of an invisible, pressure less matter - potentially relic from higher energy theories - called "dark matter" (20-21%) and by an even more mysterious term, described in Einstein equations as a vacuum energy density, called "dark energy" (70%). This "dark" Universe is not well described or even understood; its presence is inferred indirectly from its gravitational effects, both on the motions of astronomical objects and on light propagation. So this point could be the next breakthrough in cosmology. Today's cosmology is based on a cosmological model that contains various parameters that need to be determined precisely, such as the matter density parameter Omega_m or the dark energy density parameter Omega_lambda. Weak gravitational lensing is believed to be the most promising tool to understand the nature of dark matter and to constrain the cosmological parameters used to describe the Universe because it provides a method to directly map the distribution of dark matter (see [1,6,60,63,70]). From this dark matter distribution, the nature of dark matter can be better understood and better constraints can be placed on dark energy

  15. Composite weak bosons

    SciTech Connect

    Suzuki, M.

    1988-04-01

    Dynamical mechanism of composite W and Z is studied in a 1/N field theory model with four-fermion interactions in which global weak SU(2) symmetry is broken explicitly by electromagnetic interaction. Issues involved in such a model are discussed in detail. Deviation from gauge coupling due to compositeness and higher order loop corrections are examined to show that this class of models are consistent not only theoretically but also experimentally.

  16. Sequential weak measurement

    SciTech Connect

    Mitchison, Graeme; Jozsa, Richard; Popescu, Sandu |||

    2007-12-15

    The notion of weak measurement provides a formalism for extracting information from a quantum system in the limit of vanishing disturbance to its state. Here we extend this formalism to the measurement of sequences of observables. When these observables do not commute, we may obtain information about joint properties of a quantum system that would be forbidden in the usual strong measurement scenario. As an application, we provide a physically compelling characterization of the notion of counterfactual quantum computation.

  17. Effect of grain strength distribution on rock fracture

    SciTech Connect

    Woffington, Austin

    1996-05-01

    This report discloses my contributions to the study of grain strength distribution and its effects in computer modeled rock lattices. Frackrock v35.15 developed by Blair and Cook, was used to model bimodal grain strength distribution and test the lattices under stress. New data was gathered by running trials with a standardized weak grain strength and compared to the original data with a mean weak grain strength. The new data set shows lattice failure to be less predictable with a higher percentage of weak sites. Strain on the lattice is affected by the wide distribution of grain strengths: the closer the grain strengths are to each other, the more predictable they get. Further testing needs to be done on larger lattices, boundary less lattices, and multiple grain strength distributions. This will show the effects of size and stress on the grain distribution strength and will add to advancing our knowledge of how rocks crack and break under stressful conditions.

  18. `Weak A' phenotypes

    PubMed Central

    Cartron, J. P.; Gerbal, A.; Hughes-Jones, N. C.; Salmon, C.

    1974-01-01

    Thirty-five weak A samples including fourteen A3, eight Ax, seven Aend, three Am and three Ae1 were studied in order to determine their A antigen site density, using an IgG anti-A labelled with 125I. The values obtained ranged between 30,000 A antigen sites for A3 individuals, and 700 sites for the Ae1 red cells. The hierarchy of values observed made it possible to establish a quantitative relationship between the red cell agglutinability of these phenotypes measured under standard conditions, and their antigen site density. PMID:4435836

  19. Weakly broken galileon symmetry

    SciTech Connect

    Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Vernizzi, Filippo

    2015-09-01

    Effective theories of a scalar ϕ invariant under the internal galileon symmetryϕ→ϕ+b{sub μ}x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon’s quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.

  20. Weak decay of hypernuclei

    SciTech Connect

    Grace, R.

    1983-01-01

    The Moby Dick spectrometer (at BNL) in coincidence with a range spectrometer and a TOF neutron detector will be used to study the weak decay modes of /sup 12/C. The Moby Dick spectrometer will be used to reconstruct and tag events in which specific hypernuclear states are formed in the reaction K/sup -/ + /sup 12/C ..-->.. ..pi../sup -/ + /sup 12/C. Subsequent emission of decay products (pions, protons and neutrons) in coincidence with the fast forward pion will be detected in a time and range spectrometer, and a neutron detector.

  1. Weakly broken galileon symmetry

    SciTech Connect

    Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Vernizzi, Filippo E-mail: luca.santoni@sns.it E-mail: filippo.vernizzi@cea.fr

    2015-09-01

    Effective theories of a scalar φ invariant under the internal galileon symmetry φ→φ+b{sub μ} x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon's quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.

  2. Corium crust strength measurements.

    SciTech Connect

    Lomperski, S.; Nuclear Engineering Division

    2009-11-01

    Corium strength is of interest in the context of a severe reactor accident in which molten core material melts through the reactor vessel and collects on the containment basemat. Some accident management strategies involve pouring water over the melt to solidify it and halt corium/concrete interactions. The effectiveness of this method could be influenced by the strength of the corium crust at the interface between the melt and coolant. A strong, coherent crust anchored to the containment walls could allow the yet-molten corium to fall away from the crust as it erodes the basemat, thereby thermally decoupling the melt from the coolant and sharply reducing the cooling rate. This paper presents a diverse collection of measurements of the mechanical strength of corium. The data is based on load tests of corium samples in three different contexts: (1) small blocks cut from the debris of the large-scale MACE experiments, (2) 30 cm-diameter, 75 kg ingots produced by SSWICS quench tests, and (3) high temperature crusts loaded during large-scale corium/concrete interaction (CCI) tests. In every case the corium consisted of varying proportions of UO{sub 2}, ZrO{sub 2}, and the constituents of concrete to represent a LWR melt at different stages of a molten core/concrete interaction. The collection of data was used to assess the strength and stability of an anchored, plant-scale crust. The results indicate that such a crust is likely to be too weak to support itself above the melt. It is therefore improbable that an anchored crust configuration could persist and the melt become thermally decoupled from the water layer to restrict cooling and prolong an attack of the reactor cavity concrete.

  3. QM02 Strength Measurement

    SciTech Connect

    Welch, J; Wu, J.; /SLAC

    2010-11-24

    In late April, Paul Emma reported that his orbit fitting program could find a reasonably good fit only if the strength of QM02 was changed from design value of -5.83 kG to -6.25 kG - a strength change of 7.3%. In late May, we made a focal length measurement of QM02 by turning off all focusing optics between YC07 and BPMS1 (in the spectrometer line) except for QM02 and adjusted the strength of QM02 so that vertical kicks by YC07 did not produce any displacements at BPMS1 (see Figure 1). The result was quoted in the LCLS elog was that QM02 appeared to 6% too weak, and approximately agreed with Paul's observation. The analysis used for the entry in the log book was based on the thin lens approximation and used the following numbers: Distance YC07 to QM02 - 5.128 m; Distance QM02 to BPMS1 - 1.778 m; and Energy - 135 MeV. These distances were computed from the X,Z coordinates given the on the large plot of the Injector on the wall of the control room. On review of the MAD output file coordinates, it seems that the distance used for QM02 to BPMS1 is not 1.778 m. The correct value is Distance, center of QM02 to BPMS1 - 1.845 m. There may be a typo on the wall chart values for the coordinates of BPMS1, or perhaps there was a misinterpretation of edge versus center of QM02. In any case, the effect of this change is that the thin lens estimate changes from 6% too weak to 9% too weak. At John Galayda's suggestion, we looked into the thin lens versus thick lens approximation. A Mathematica program was written to solve for the K value of the QM02, in the thick lens approximation, that provides point to point focusing from YC07 to BPMS1, and to compare this number with the value obtained using the thin lens approximation. The length of QM02 used in the thick lens calculation is the effective length determined by magnetic measurements of 0.108 m. The result of the Mathematica calculation is that the thin lens approximation predicts less magnet strength is required to produce the

  4. Weakly relativistic plasma expansion

    SciTech Connect

    Fermous, Rachid Djebli, Mourad

    2015-04-15

    Plasma expansion is an important physical process that takes place in laser interactions with solid targets. Within a self-similar model for the hydrodynamical multi-fluid equations, we investigated the expansion of both dense and under-dense plasmas. The weakly relativistic electrons are produced by ultra-intense laser pulses, while ions are supposed to be in a non-relativistic regime. Numerical investigations have shown that relativistic effects are important for under-dense plasma and are characterized by a finite ion front velocity. Dense plasma expansion is found to be governed mainly by quantum contributions in the fluid equations that originate from the degenerate pressure in addition to the nonlinear contributions from exchange and correlation potentials. The quantum degeneracy parameter profile provides clues to set the limit between under-dense and dense relativistic plasma expansions at a given density and temperature.

  5. Reptation in a Weak Driving Field

    NASA Astrophysics Data System (ADS)

    Aalberts, Daniel; van Leeuwen, J. M. J.

    1997-03-01

    A simplified model of reptation is presented. The Master Equation of the model is systematically solved by expansion in powers of the strength of the driving field. From the explicit form of the probability distribution, exact conclusions can be drawn about the average shape of the polymer, its drift velocity, and the zero field diffusion constant. Correlations between segments of the chain are calculated and turn out to be large, even in the weak driving field limit. The results are compared with simulations of the model.

  6. Strong mobility in weakly disordered systems

    SciTech Connect

    Ben-naim, Eli; Krapivsky, Pavel

    2009-01-01

    We study transport of interacting particles in weakly disordered media. Our one-dimensional system includes (i) disorder, the hopping rate governing the movement of a particle between two neighboring lattice sites is inhomogeneous, and (ii) hard core interaction, the maximum occupancy at each site is one particle. We find that over a substantial regime, the root-mean-square displacement of a particle s grows superdiffusively with time t, {sigma}{approx}({epsilon}t){sup 2/3}, where {epsilon} is the disorder strength. Without disorder the particle displacement is subdiffusive, {sigma} {approx}t{sup 1/4}, and therefore disorder strongly enhances particle mobility. We explain this effect using scaling arguments, and verify the theoretical predictions through numerical simulations. Also, the simulations show that regardless of disorder strength, disorder leads to stronger mobility over an intermediate time regime.

  7. Enhancing entanglement trapping by weak measurement and quantum measurement reversal

    SciTech Connect

    Zhang, Ying-Jie; Han, Wei; Fan, Heng; Xia, Yun-Jie

    2015-03-15

    In this paper, we propose a scheme to enhance trapping of entanglement of two qubits in the environment of a photonic band gap material. Our entanglement trapping promotion scheme makes use of combined weak measurements and quantum measurement reversals. The optimal promotion of entanglement trapping can be acquired with a reasonable finite success probability by adjusting measurement strengths. - Highlights: • Propose a scheme to enhance entanglement trapping in photonic band gap material. • Weak measurement and its reversal are performed locally on individual qubits. • Obtain an optimal condition for maximizing the concurrence of entanglement trapping. • Entanglement sudden death can be prevented by weak measurement in photonic band gap.

  8. Weak measurements beyond the Aharonov-Albert-Vaidman formalism

    SciTech Connect

    Wu Shengjun; Li Yang

    2011-05-15

    We extend the idea of weak measurements to the general case, provide a complete treatment, and obtain results for both the regime when the preselected and postselected states (PPS) are almost orthogonal and the regime when they are exactly orthogonal. We surprisingly find that for a fixed interaction strength, there may exist a maximum signal amplification and a corresponding optimum overlap of PPS to achieve it. For weak measurements in the orthogonal regime, we find interesting quantities that play the same role that weak values play in the nonorthogonal regime.

  9. Dynamic Strength Ceramic Nanocomposites Under Pulse Loading

    NASA Astrophysics Data System (ADS)

    Skripnyak, Evgeniya G.; Skripnyak, Vladimir V.; Vaganova, Irina K.; Skripnyak, Vladimir A.

    2015-06-01

    Multi-scale computer simulation approach has been applied to research of strength of nanocomposites under dynamic loading. The influence of mesoscopic substructures on the dynamic strength of ceramic and hybrid nanocomposites, which can be formed using additive manufacturing were numerically investigated. At weak shock wave loadings the shear strength and the spall strength of ceramic and hybrid nanocomposites depends not only phase concentration and porosity, but size parameters of skeleton substructures. The influence of skeleton parameter on the shear strength and the spall strength of ceramic nanocomposites with the same concentration of phases decreases with increasing amplitude of the shock pulse of microsecond duration above the double amplitude of the Hugoniot elastic limit of nanocomposites. This research carried out in 2014 -2015 was supported by grant from The Tomsk State University Academic D.I. Mendeleev Fund Program and also Ministry of Sciences and Education of Russian Federation (State task 2014/223, project 1943, Agreement 14.132.

  10. Plasma transport theory spanning weak to strong coupling

    SciTech Connect

    Daligault, Jérôme; Baalrud, Scott D.

    2015-06-29

    We describe some of the most striking characteristics of particle transport in strongly coupled plasmas across a wide range of Coulomb coupling strength. We then discuss the effective potential theory, which is an approximation that was recently developed to extend conventional weakly coupled plasma transport theory into the strongly coupled regime in a manner that is practical to evaluate efficiently.

  11. Negative probabilities and information gain in weak measurements

    NASA Astrophysics Data System (ADS)

    Zhu, Xuanmin; Wei, Qun; Liu, Quanhui; Wu, Shengjun

    2013-11-01

    We study the outcomes in a general measurement with postselection, and derive upper bounds for the pointer readings in weak measurement. The probabilities inferred from weak measurements change along with the coupling strength; and the true probabilities can be obtained when the coupling is strong enough. By calculating the information gain of the measuring device about which path the particles pass through, we show that the “negative probabilities” only emerge for cases when the information gain is little due to very weak coupling between the measuring device and the particles. When the coupling strength increases, we can unambiguously determine whether a particle passes through a given path every time, hence the average shifts always represent true probabilities, and the strange “negatives probabilities” disappear.

  12. Application of Strength Diagnosis.

    ERIC Educational Resources Information Center

    Newton, Robert U.; Dugan, Eric

    2002-01-01

    Discusses the various strength qualities (maximum strength, high- and low-load speed strength, reactive strength, rate of force development, and skill performance), noting why a training program design based on strength diagnosis can lead to greater efficacy and better performance gains for the athlete. Examples of tests used to assess strength…

  13. Experimental investigations of weak definite and weak indefinite noun phrases

    PubMed Central

    Klein, Natalie M.; Gegg-Harrison, Whitney M.; Carlson, Greg N.; Tanenhaus, Michael K.

    2013-01-01

    Definite noun phrases typically refer to entities that are uniquely identifiable in the speaker and addressee’s common ground. Some definite noun phrases (e.g. the hospital in Mary had to go the hospital and John did too) seem to violate this uniqueness constraint. We report six experiments that were motivated by the hypothesis that these “weak definite” interpretations arise in “incorporated” constructions. Experiments 1-3 compared nouns that seem to allow for a weak definite interpretation (e.g. hospital, bank, bus, radio) with those that do not (e.g. farm, concert, car, book). Experiments 1 and 2 used an instruction-following task and picture-judgment task, respectively, to demonstrate that a weak definite need not uniquely refer. In Experiment 3 participants imagined scenarios described by sentences such as The Federal Express driver had to go to the hospital/farm. The imagined scenarios following weak definite noun phrases were more likely to include conventional activities associated with the object, whereas following regular nouns, participants were more likely to imagine scenarios that included typical activities associated with the subject; similar effects were observed with weak indefinites. Experiment 4 found that object-related activities were reduced when the same subject and object were used with a verb that does not license weak definite interpretations. In Experiment 5, a science fiction story introduced an artificial lexicon for novel concepts. Novel nouns that shared conceptual properties with English weak definite nouns were more likely to allow weak reference in a judgment task. Experiment 6 demonstrated that familiarity for definite articles and anti- familiarity for indefinite articles applies to the activity associated with the noun, consistent with predictions made by the incorporation analysis. PMID:23685208

  14. Resisting Weakness of the Will

    PubMed Central

    Levy, Neil

    2012-01-01

    I develop an account of weakness of the will that is driven by experimental evidence from cognitive and social psychology. I will argue that this account demonstrates that there is no such thing as weakness of the will: no psychological kind corresponds to it. Instead, weakness of the will ought to be understood as depletion of System II resources. Neither the explanatory purposes of psychology nor our practical purposes as agents are well-served by retaining the concept. I therefore suggest that we ought to jettison it, in favour of the vocabulary and concepts of cognitive psychology. PMID:22984298

  15. Weak-shock reflection factors

    SciTech Connect

    Reichenbach, H.; Kuhl, A.L.

    1993-09-07

    The purpose of this paper is to compare reflection factors for weak shocks from various surfaces, and to focus attention on some unsolved questions. Three different cases are considered: square-wave planar shock reflection from wedges; square-wave planar shock reflection from cylinders; and spherical blast wave reflection from a planar surface. We restrict ourselves to weak shocks. Shocks with a Mach number of M{sub O} < 1.56 in air or with an overpressure of {Delta}{sub PI} < 25 psi (1.66 bar) under normal ambient conditions are called weak.

  16. Weak interactions and presupernova evolution

    SciTech Connect

    Aufderheide, M.B. State Univ. of New York . Dept. of Physics)

    1991-02-19

    The role of weak interactions, particularly electron capture and {beta}{sup {minus}} decay, in presupernova evolution is discussed. The present uncertainty in these rates is examined and the possibility of improving the situation is addressed. 12 refs., 4 figs.

  17. Precision Metrology Using Weak Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Lijian; Datta, Animesh; Walmsley, Ian A.

    2015-05-01

    Weak values and measurements have been proposed as a means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology. Namely, (Q1) Does postselection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyze these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology.

  18. Comparison of quadriceps strength and handgrip strength in their association with health outcomes in older adults in primary care.

    PubMed

    Chan, On Ying A; van Houwelingen, Anne H; Gussekloo, Jacobijn; Blom, Jeanet W; den Elzen, Wendy P J

    2014-01-01

    Sarcopenia is thought to play a major role in the functional impairment that occurs with old age. In clinical practice, sarcopenia is often determined by measuring handgrip strength. Here, we compared the lower limb quadriceps strength to the handgrip strength in their association with health outcomes in older adults in primary care. Our study population consisted of older adults (n = 764, 68.2% women, median age 83) that participated in the Integrated Systemic Care for Older People (ISCOPE) study. Participants were visited at baseline to measure quadriceps strength and handgrip strength. Data on health outcomes were obtained at baseline and after 12 months (including life satisfaction, disability in daily living, GP contact-time and hospitalization). Quadriceps strength and handgrip strength showed a weak association (β = 0.42 [95% CI 0.33-0.50]; R (2) = 0.17). Quadriceps strength and handgrip strength were independently associated with health outcomes at baseline, including quality of life, disability in daily living, GP contact-time, hospitalization, and gait speed. Combined weakness of the quadriceps and handgrip distinguished a most vulnerable subpopulation that presented with the poorest health outcomes. At follow-up, handgrip strength showed an association with quality of life (β = 0.05; P = 0.002) and disability in daily living (β = -0.5; P = 0.004). Quadriceps weakness did not further contribute to the prediction of the measured health outcomes. We conclude that quadriceps strength is only moderately associated with handgrip strength in an older population and that the combination of quadriceps strength and handgrip strength measurements may aid in the identification of older adults in primary care with the poorest health outcomes. In the prediction of poor health outcomes, quadriceps strength measurements do not show an added value to the handgrip strength.

  19. Early exercise rehabilitation of muscle weakness in acute respiratory failure patients.

    PubMed

    Berry, Michael J; Morris, Peter E

    2013-10-01

    Acute respiratory failure patients experience significant muscle weakness, which contributes to prolonged hospitalization and functional impairments after hospital discharge. Based on our previous work, we hypothesize that an exercise intervention initiated early in the intensive care unit aimed at improving skeletal muscle strength could decrease hospital stay and attenuate the deconditioning and skeletal muscle weakness experienced by these patients.

  20. Emergent soft monopole modes in weakly bound deformed nuclei

    NASA Astrophysics Data System (ADS)

    Pei, J. C.; Kortelainen, M.; Zhang, Y. N.; Xu, F. R.

    2014-11-01

    Based on the Hartree-Fock-Bogoliubov solutions in large deformed coordinate spaces, the finite amplitude method for the quasiparticle random-phase approximation (FAM-QRPA) has been implemented, providing a suitable approach to probing collective excitations of weakly bound nuclei embedded in the continuum. The monopole excitation modes in magnesium isotopes up to the neutron drip line have been studied with the FAM-QRPA framework on both the coordinate-space and harmonic oscillator basis methods. Enhanced soft monopole strengths and collectivity as a result of weak-binding effects have been unambiguously demonstrated.

  1. Influence of environmental noise on the weak value amplification

    NASA Astrophysics Data System (ADS)

    Zhu, Xuannmin; Zhang, Yu-Xiang

    2016-08-01

    Quantum systems are always disturbed by environmental noise. We have investigated the influence of the environmental noise on the amplification in weak measurements. Three typical quantum noise processes are discussed in this article. The maximum expectation values of the observables of the measuring device decrease sharply with the strength of the depolarizing and phase damping channels, while the amplification effect of weak measurement is immune to the amplitude damping noise. To obtain significantly amplified signals, we must ensure that the preselection quantum systems are kept away from the depolarizing and phase damping processes.

  2. Celebrate Strengths, Nurture Affinities: A Conversation with Mel Levine

    ERIC Educational Resources Information Center

    Scherer, Marge

    2006-01-01

    In this interview with "Educational Leadership," pediatrician Dr. Mel Levine, cofounder of "All Kinds of Minds," explains why students and educators should learn about eight neurodevelopmental functions that undergird our strengths and weaknesses. For the most part, he notes, adults who lead successful lives mobilize their strengths and compensate…

  3. Conformational transitions of a weak polyampholyte

    NASA Astrophysics Data System (ADS)

    Narayanan Nair, Arun Kumar; Uyaver, Sahin; Sun, Shuyu

    2014-10-01

    Using grand canonical Monte Carlo simulations of a flexible polyelectrolyte where the charges are in contact with a reservoir of constant chemical potential given by the solution pH, we study the behavior of weak polyelectrolytes in poor and good solvent conditions for polymer backbone. We address the titration behavior and conformational properties of a flexible diblock polyampholyte chain formed of two oppositely charged weak polyelectrolyte blocks, each containing equal number of identical monomers. The change of solution pH induces charge asymmetry in a diblock polyampholyte. For diblock polyampholyte chains in poor solvents, we demonstrate that a discontinuous transition between extended (tadpole) and collapsed (globular) conformational states is attainable by varying the solution pH. The double-minima structure in the probability distribution of the free energy provides direct evidence for the first-order like nature of this transition. At the isoelectric point electrostatically driven coil-globule transition of diblock polyampholytes in good solvents is found to consist of different regimes identified with increasing electrostatic interaction strength. At pH values above or below the isoelectric point diblock chains are found to have polyelectrolyte-like behavior due to repulsion between uncompensated charges along the chain.

  4. Weak Energy: Form and Function

    NASA Astrophysics Data System (ADS)

    Parks, Allen D.

    The equation of motion for a time-dependent weak value of a quantum mechanical observable contains a complex valued energy factor—the weak energy of evolution. This quantity is defined by the dynamics of the pre-selected and post-selected states which specify the observable's weak value. It is shown that this energy: (i) is manifested as dynamical and geometric phases that govern the evolution of the weak value during the measurement process; (ii) satisfies the Euler-Lagrange equations when expressed in terms of Pancharatnam (P) phase and Fubini-Study (FS) metric distance; (iii) provides for a PFS stationary action principle for quantum state evolution; (iv) time translates correlation amplitudes; (v) generalizes the temporal persistence of state normalization; and (vi) obeys a time-energy uncertainty relation. A similar complex valued quantity—the pointed weak energy of an evolving quantum state—is also defined and several of its properties in PFS coordinates are discussed. It is shown that the imaginary part of the pointed weak energy governs the state's survival probability and its real part is—to within a sign—the Mukunda-Simon geometric phase for arbitrary evolutions or the Aharonov-Anandan (AA) geometric phase for cyclic evolutions. Pointed weak energy gauge transformations and the PFS 1-form are defined and discussed and the relationship between the PFS 1-form and the AA connection 1-form is established. [Editors note: for a video of the talk given by Prof. Parks at the Aharonov-80 conference in 2012 at Chapman University, see http://quantum.chapman.edu/talk-25.

  5. Weak Selection and Protein Evolution

    PubMed Central

    Akashi, Hiroshi; Osada, Naoki; Ohta, Tomoko

    2012-01-01

    The “nearly neutral” theory of molecular evolution proposes that many features of genomes arise from the interaction of three weak evolutionary forces: mutation, genetic drift, and natural selection acting at its limit of efficacy. Such forces generally have little impact on allele frequencies within populations from generation to generation but can have substantial effects on long-term evolution. The evolutionary dynamics of weakly selected mutations are highly sensitive to population size, and near neutrality was initially proposed as an adjustment to the neutral theory to account for general patterns in available protein and DNA variation data. Here, we review the motivation for the nearly neutral theory, discuss the structure of the model and its predictions, and evaluate current empirical support for interactions among weak evolutionary forces in protein evolution. Near neutrality may be a prevalent mode of evolution across a range of functional categories of mutations and taxa. However, multiple evolutionary mechanisms (including adaptive evolution, linked selection, changes in fitness-effect distributions, and weak selection) can often explain the same patterns of genome variation. Strong parameter sensitivity remains a limitation of the nearly neutral model, and we discuss concave fitness functions as a plausible underlying basis for weak selection. PMID:22964835

  6. Spin freezing in geometrically frustrated antiferromagnets with weak disorder.

    PubMed

    Saunders, T E; Chalker, J T

    2007-04-13

    We investigate the consequences for geometrically frustrated antiferromagnets of weak disorder in the strength of exchange interactions. Taking as a model the classical Heisenberg antiferromagnet with nearest neighbor exchange on the pyrochlore lattice, we examine low-temperature behavior. We show that spatial modulation of exchange generates long-range effective interactions within the extensively degenerate ground states of the clean system. Using Monte Carlo simulations, we find a spin glass transition at a temperature set by the disorder strength. Disorder of this type, which is generated by random strains in the presence of magnetoelastic coupling, may account for the spin freezing observed in many geometrically frustrated magnets.

  7. Warping the Weak Gravity Conjecture

    NASA Astrophysics Data System (ADS)

    Kooner, Karta; Parameswaran, Susha; Zavala, Ivonne

    2016-08-01

    The Weak Gravity Conjecture, if valid, rules out simple models of Natural Inflation by restricting their axion decay constant to be sub-Planckian. We revisit stringy attempts to realise Natural Inflation, with a single open string axionic inflaton from a probe D-brane in a warped throat. We show that warped geometries can allow the requisite super-Planckian axion decay constant to be achieved, within the supergravity approximation and consistently with the Weak Gravity Conjecture. Preliminary estimates of the brane backreaction suggest that the probe approximation may be under control. However, there is a tension between large axion decay constant and high string scale, where the requisite high string scale is difficult to achieve in all attempts to realise large field inflation using perturbative string theory. We comment on the Generalized Weak Gravity Conjecture in the light of our results.

  8. State tomography via weak measurements

    PubMed Central

    Wu, Shengjun

    2013-01-01

    Recent work has revealed that the wave function of a pure state can be measured directly and that complementary knowledge of a quantum system can be obtained simultaneously by weak measurements. However, the original scheme applies only to pure states, and it is not efficient because most of the data are discarded by post-selection. Here, we propose tomography schemes for pure states and for mixed states via weak measurements, and our schemes are more efficient because we do not discard any data. Furthermore, we demonstrate that any matrix element of a general state can be directly read from an appropriate weak measurement. The density matrix (with all of its elements) represents all that is directly accessible from a general measurement. PMID:23378924

  9. Cosmology and the weak interaction

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1989-01-01

    The weak interaction plays a critical role in modern Big Bang cosmology. Two of its most publicized comological connections are emphasized: big bang nucleosynthesis and dark matter. The first of these is connected to the cosmological prediction of neutrine flavors, N(sub nu) is approximately 3 which in now being confirmed. The second is interrelated to the whole problem of galacty and structure formation in the universe. The role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure is demonstrated.

  10. Weak value amplification considered harmful

    NASA Astrophysics Data System (ADS)

    Ferrie, Christopher; Combes, Joshua

    2014-03-01

    We show using statistically rigorous arguments that the technique of weak value amplification does not perform better than standard statistical techniques for the tasks of parameter estimation and signal detection. We show that using all data and considering the joint distribution of all measurement outcomes yields the optimal estimator. Moreover, we show estimation using the maximum likelihood technique with weak values as small as possible produces better performance for quantum metrology. In doing so, we identify the optimal experimental arrangement to be the one which reveals the maximal eigenvalue of the square of system observables. We also show these conclusions do not change in the presence of technical noise.

  11. Cosmology and the weak interaction

    SciTech Connect

    Schramm, D.N. ):)

    1989-12-01

    The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.

  12. Growth and decay of weak shock waves in magnetogasdynamics

    NASA Astrophysics Data System (ADS)

    Singh, L. P.; Singh, D. B.; Ram, S. D.

    2015-12-01

    The purpose of the present study is to investigate the problem of the propagation of weak shock waves in an inviscid, electrically conducting fluid under the influence of a magnetic field. The analysis assumes the following two cases: (1) a planar flow with a uniform transverse magnetic field and (2) cylindrically symmetric flow with a uniform axial or varying azimuthal magnetic field. A system of two coupled nonlinear transport equations, governing the strength of a shock wave and the first-order discontinuity induced behind it, are derived that admit a solution that agrees with the classical decay laws for a weak shock. An analytic expression for the determination of the shock formation distance is obtained. How the magnetic field strength, whether axial or azimuthal, influences the shock formation is also assessed.

  13. Observationally determined Fe II oscillator strengths

    NASA Astrophysics Data System (ADS)

    Shull, J. M.; van Steenberg, M.; Seab, C. G.

    1983-08-01

    Absorption oscillator strengths for 21 Fe II resonance lines, have been determined using a curve-of-growth analysis of interstellar data from the Copernicus and International Ultraviolet Explorer (IUE) satellites. In addition to slight changes in strengths of the far-UV lines, new f-values are reported for wavelength 1608.45, a prominent line in interstellar and quasar absorption spectra, and for wavelength 2260.08, a weak, newly identified linen in IUE interstellar spectra. An upper limit on the strength of the undetected line at 2366.867 A (UV multiplet 2) is set. Using revised oscillator strengths, Fe II column densities toward 13 OB stars are derived. The interstellar depletions, (Fe/H), relative to solar values range between factors of 10 and 120.

  14. Monopole Strength Function of Deformed Superfluid Nuclei

    SciTech Connect

    Stoitsov, M. V.; Kortelainen, E. M.; Nakatsukasa, T.; Losa, C.; Nazarewicz, Witold

    2011-01-01

    We present an efficient method for calculating strength functions using the finite amplitude method (FAM) for deformed superfluid heavy nuclei within the framework of the nuclear density functional theory. We demonstrate that FAM reproduces strength functions obtained with the fully self-consistent quasi-particle random-phase approximation (QRPA) at a fraction of computational cost. As a demonstration, we compute the isoscalar and isovector monopole strength for strongly deformed configurations in ^{240}Pu by considering huge quasi-particle QRPA spaces. Our approach to FAM, based on Broyden's iterative procedure, opens the possibility for large-scale calculations of strength distributions in well-bound and weakly bound nuclei across the nuclear landscape.

  15. Flexibility and Muscular Strength.

    ERIC Educational Resources Information Center

    Liemohn, Wendell

    1988-01-01

    This definition of flexibility and muscular strength also explores their roles in overall physical fitness and focuses on how increased flexibility and muscular strength can help decrease or eliminate lower back pain. (CB)

  16. Muscle Weakness Thresholds for Prediction of Diabetes in Adults

    PubMed Central

    Peterson, Mark D.; Zhang, Peng; Choksi, Palak; Markides, Kyriakos S.; Al Snih, Soham

    2016-01-01

    Background Despite the known links between weakness and early mortality, what remains to be fully understood is the extent to which strength preservation is associated with protection from cardiometabolic diseases such as diabetes. Purpose The purposes of this study were to determine the association between muscle strength and diabetes among adults, and to identify age- and sex-specific thresholds of low strength for detection of risk. Methods A population-representative sample of 4,066 individuals, aged 20–85 years, was included from the combined 2011–2012 National Health and Nutrition Examination Survey datasets. Strength was assessed using a hand-held dynamometer, and the single largest reading from either hand was normalized to body mass. A logistic regression model was used to assess the association between normalized grip strength and risk of diabetes, as determined by hemoglobin A1c (HbA1c) levels (≥6.5% [≥48 mmol/mol]), while controlling for sociodemographic characteristics, anthropometric measures, and television viewing time. Results For every 0.05 decrement in normalized strength, there was a 1.26 times increased adjusted odds for diabetes in men and women. Women were at lower odds of having diabetes (OR: 0.49; 95% CI: 0.29–0.82), whereas age, waist circumference and lower income were inversely associated. Optimal sex- and age-specific weakness thresholds to detect diabetes were 0.56, 0.50, and 0.45 for men, and 0.42, 0.38, and 0.33 for women, for ages 20–39 years, 40–59 years, and 60–80 years. Conclusions and Clinical Relevance We present thresholds of strength that can be incorporated into a clinical setting for identifying adults that are at risk for developing diabetes, and that might benefit from lifestyle interventions to reduce risk. PMID:26744337

  17. Cosmology with weak lensing surveys.

    PubMed

    Munshi, Dipak; Valageas, Patrick

    2005-12-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bi-spectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy.

  18. Weak localization of seismic waves.

    PubMed

    Larose, E; Margerin, L; Van Tiggelen, B A; Campillo, M

    2004-07-23

    We report the observation of weak localization of seismic waves in a natural environment. It emerges as a doubling of the seismic energy around the source within a spot of the width of a wavelength, which is several tens of meters in our case. The characteristic time for its onset is the scattering mean-free time that quantifies the internal heterogeneity.

  19. Cosmology with weak lensing surveys.

    PubMed

    Munshi, Dipak; Valageas, Patrick

    2005-12-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bi-spectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy. PMID:16286284

  20. N-{Delta} weak transition

    SciTech Connect

    Graczyk, Krzysztof M.

    2011-11-23

    A short review of the Rein-Sehgal and isobar models is presented. The attention is focused on the nucleon-{Delta}(1232) weak transition form-factors. The results of the recent re-analyses of the ANL and BNL bubble chamber neutrino-deuteron scattering data are discussed.

  1. Polymer-solid interfaces: Structure and strength

    NASA Astrophysics Data System (ADS)

    Gong, Liezhong

    1999-12-01

    This thesis explored the influence of sticker group concentration (φ), interaction parameter between sticker groups and the solid substrate (chi), and bonding time on the structure and strength of polymer-solid interfaces. Carboxylated polybutadienes (cPBD's) with different COOH concentrations (φ) were synthesized through hydrocarboxylation of high molecular weight polybutadienes. The COOH groups were randomly distributed along the polymer chains and selectively introduced to the pendant double bonds. The influence of φ and chi on the peel strength (GIC) of two interfaces, cPBD-Al and cPBD-AlS (amine terminated silane modified Al), was investigated using the T-peel test. Counter-intuitively, with increasing φ, GIC of both interfaces increased first and then decreased after passing through a maximum strength. At a constant φ, GIC increased with chi. Additionally, the bonding dynamics was strongly dependent on φ and chi and the time scale was several orders of Magnitude longer than the characteristic relaxation time of polybutadiene. The adhesion dynamics was controlled by the slow frustrated surface reorganization process. Most of the experimental observations could be attributed to the variation in chain physical connectivity within the interfaces, which was explored by a self-consistent field lattice model (SCFLM). Sticker groups were found to segregate to the solid surface and chain physical connectivity was modified at the polymer-solid interface. We demonstrated that the segregation of sticker groups and the variation in chain physical connectivity led to the formation of a weak boundary interphase. It is this weak interphase that controls the strength and bonding dynamics of the interface. The presence of this weak interphase was experimentally verified through angle resolved XPS analysis. Finally, an entanglement percolation model was developed to correlate the interface strength with the chain connectivity. The results obtained in this study contribute

  2. Critical Transport in Weakly Disordered Semiconductors and Semimetals

    NASA Astrophysics Data System (ADS)

    Syzranov, S. V.; Radzihovsky, L.; Gurarie, V.

    2015-04-01

    Motivated by Weyl semimetals and weakly doped semiconductors, we study transport in a weakly disordered semiconductor with a power-law quasiparticle dispersion ξk∝kα . We show, that in 2 α dimensions short-correlated disorder experiences logarithmic renormalization from all energies in the band. We study the case of a general dimension d using a renormalization group, controlled by an ɛ =2 α -d expansion. Above the critical dimensions, conduction exhibits a localization-delocalization phase transition or a sharp crossover (depending on the symmetries of the Hamiltonian) as a function of disorder strength. We utilize this analysis to compute the low-temperature conductivity in Weyl semimetals and weakly doped semiconductors near and below the critical disorder point.

  3. Critical transport in weakly disordered semiconductors and semimetals.

    PubMed

    Syzranov, S V; Radzihovsky, L; Gurarie, V

    2015-04-24

    Motivated by Weyl semimetals and weakly doped semiconductors, we study transport in a weakly disordered semiconductor with a power-law quasiparticle dispersion ξ_{k}∝k^{α}. We show, that in 2α dimensions short-correlated disorder experiences logarithmic renormalization from all energies in the band. We study the case of a general dimension d using a renormalization group, controlled by an ϵ=2α-d expansion. Above the critical dimensions, conduction exhibits a localization-delocalization phase transition or a sharp crossover (depending on the symmetries of the Hamiltonian) as a function of disorder strength. We utilize this analysis to compute the low-temperature conductivity in Weyl semimetals and weakly doped semiconductors near and below the critical disorder point. PMID:25955065

  4. Advantages of nonclassical pointer states in postselected weak measurements

    NASA Astrophysics Data System (ADS)

    Turek, Yusuf; Maimaiti, W.; Shikano, Yutaka; Sun, Chang-Pu; Al-Amri, M.

    2015-08-01

    We investigate, within the weak measurement theory, the advantages of nonclassical pointer states over semiclassical ones for coherent, squeezed vacuum, and Schrödinger cat states. These states are utilized as pointer states for the system operator A ̂ with property Â2=I ̂ , where I ̂ represents the identity operator. We calculate the ratio between the signal-to-noise ratio of nonpostselected and postselected weak measurements. The latter is used to find the quantum Fisher information for the above pointer states. The average shifts for those pointer states with arbitrary interaction strength are investigated in detail. One key result is that we find the postselected weak measurement scheme for nonclassical pointer states to be superior to semiclassical ones. This can improve the precision of the measurement process.

  5. What Is a Strength?

    ERIC Educational Resources Information Center

    Wolin, Sybil

    2003-01-01

    As the strength-based perspective gains recognition, it is important to describe what constitutes strengths and to develop a specific vocabulary to name them. This article draws on resilience research to help identify specific competencies and areas of strengths in youth. (Contains 1 table.)

  6. Strength Training for Girls.

    ERIC Educational Resources Information Center

    Connaughton, Daniel; Connaughton, Angela; Poor, Linda

    2001-01-01

    Strength training can be fun, safe, and appropriate for young girls and women and is an important component of any fitness program when combined with appropriate cardiovascular and flexibility activities. Concerns and misconceptions regarding girls' strength training are discussed, presenting general principles of strength training for children…

  7. Competing weak localization and weak antilocalization in ultrathin topological insulators.

    PubMed

    Lang, Murong; He, Liang; Kou, Xufeng; Upadhyaya, Pramey; Fan, Yabin; Chu, Hao; Jiang, Ying; Bardarson, Jens H; Jiang, Wanjun; Choi, Eun Sang; Wang, Yong; Yeh, Nai-Chang; Moore, Joel; Wang, Kang L

    2013-01-01

    We demonstrate evidence of a surface gap opening in topological insulator (TI) thin films of (Bi(0.57)Sb(0.43))(2)Te(3) below six quintuple layers through transport and scanning tunneling spectroscopy measurements. By effective tuning the Fermi level via gate-voltage control, we unveil a striking competition between weak localization and weak antilocalization at low magnetic fields in nonmagnetic ultrathin films, possibly owing to the change of the net Berry phase. Furthermore, when the Fermi level is swept into the surface gap of ultrathin samples, the overall unitary behaviors are revealed at higher magnetic fields, which are in contrast to the pure WAL signals obtained in thicker films. Our findings show an exotic phenomenon characterizing the gapped TI surface states and point to the future realization of quantum spin Hall effect and dissipationless TI-based applications.

  8. Strength Modeling Report

    NASA Technical Reports Server (NTRS)

    Badler, N. I.; Lee, P.; Wong, S.

    1985-01-01

    Strength modeling is a complex and multi-dimensional issue. There are numerous parameters to the problem of characterizing human strength, most notably: (1) position and orientation of body joints; (2) isometric versus dynamic strength; (3) effector force versus joint torque; (4) instantaneous versus steady force; (5) active force versus reactive force; (6) presence or absence of gravity; (7) body somatotype and composition; (8) body (segment) masses; (9) muscle group envolvement; (10) muscle size; (11) fatigue; and (12) practice (training) or familiarity. In surveying the available literature on strength measurement and modeling an attempt was made to examine as many of these parameters as possible. The conclusions reached at this point toward the feasibility of implementing computationally reasonable human strength models. The assessment of accuracy of any model against a specific individual, however, will probably not be possible on any realistic scale. Taken statistically, strength modeling may be an effective tool for general questions of task feasibility and strength requirements.

  9. Weak values and weak coupling maximizing the output of weak measurements

    SciTech Connect

    Di Lorenzo, Antonio

    2014-06-15

    In a weak measurement, the average output 〈o〉 of a probe that measures an observable A{sup -hat} of a quantum system undergoing both a preparation in a state ρ{sub i} and a postselection in a state E{sub f} is, to a good approximation, a function of the weak value A{sub w}=Tr[E{sub f}A{sup -hat} ρ{sub i}]/Tr[E{sub f}ρ{sub i}], a complex number. For a fixed coupling λ, when the overlap Tr[E{sub f}ρ{sub i}] is very small, A{sub w} diverges, but 〈o〉 stays finite, often tending to zero for symmetry reasons. This paper answers the questions: what is the weak value that maximizes the output for a fixed coupling? What is the coupling that maximizes the output for a fixed weak value? We derive equations for the optimal values of A{sub w} and λ, and provide the solutions. The results are independent of the dimensionality of the system, and they apply to a probe having a Hilbert space of arbitrary dimension. Using the Schrödinger–Robertson uncertainty relation, we demonstrate that, in an important case, the amplification 〈o〉 cannot exceed the initial uncertainty σ{sub o} in the observable o{sup -hat}, we provide an upper limit for the more general case, and a strategy to obtain 〈o〉≫σ{sub o}. - Highlights: •We have provided a general framework to find the extremal values of a weak measurement. •We have derived the location of the extremal values in terms of preparation and postselection. •We have devised a maximization strategy going beyond the limit of the Schrödinger–Robertson relation.

  10. Peroneal muscle weakness in female basketballers following chronic ankle sprain.

    PubMed

    Rottigni, S A; Hopper, D

    1991-01-01

    Female A-grade basketballers were examined for invertor and evertor muscle strength. Two test groups participated. The injured group were players who had persisting disability following ankle sprains. The control group were players who had never sustained an ankle sprain. Test apparatus was the Orthotron isokinetic dynamometer at contraction speed of 180° per second. Trends towards higher invertor and evertor strength in uninjured group when compared with the injured group found in the present study have been supported by one other report. Invertors were found to be significantly stronger than evertors in both injured and uninjured groups, with the exception of the dominant leg of the uninjured group. A significant weakness in non-dominant evertors of the uninjured group was detected. Dominance did not significantly alter strength differences in the invertor or evertor muscle groups within the uninjured population. The clinical importance of strengthening the peroneal muscles in ankle sprain rehabilitation is discussed, and further research considerations provided.

  11. Weak Coupling in 143Nd

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao-Hong; E, Ideguchi; T, Kishida; M, Ishihara; H, Tsuchida; Y, Gono; T, Morikawa; M, Shibata; H, Watanabe; M, Miyake; T, Tsutsumi; S, Motomura; S, Mitarai

    2000-04-01

    The high-spin states of 143Nd have been studied in the 130Te(18O, 5n)143Nd reaction at a beam energy of 80 MeV using techniques of in-beam γ-ray spectroscopy. Measurements of γ - γ - t coincidences, γ-ray angular distributions, and γ-ray linear polarizations were performed. A level scheme of 143Nd with spin and parity assignments up to 53/2+ is proposed. While a weak coupling model can explain the level structure up to the Jπ=39/2- state, this model can not reproduce the higher-lying states. Additionally, a new low-lying non-yrast level sequence in 143Nd was observed in the present work, which can be well described by the weak coupling of an i13/2 neutron to the 142Nd core nucleus.

  12. Overdamping by weakly coupled environments

    SciTech Connect

    Esposito, Massimiliano; Haake, Fritz

    2005-12-15

    A quantum system weakly interacting with a fast environment usually undergoes a relaxation with complex frequencies whose imaginary parts are damping rates quadratic in the coupling to the environment in accord with Fermi's 'golden rule'. We show for various models (spin damped by harmonic-oscillator or random-matrix baths, quantum diffusion, and quantum Brownian motion) that upon increasing the coupling up to a critical value still small enough to allow for weak-coupling Markovian master equations, a different relaxation regime can occur. In that regime, complex frequencies lose their real parts such that the process becomes overdamped. Our results call into question the standard belief that overdamping is exclusively a strong coupling feature.

  13. Optimizing SNAP for Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. W.; Ellis, R. S.; Massey, R. J.; Rhodes, J. D.; Lamoureux, J. I.; SNAP Collaboration

    2004-12-01

    The Supernova/Acceleration Probe (SNAP) satellite proposes to measure weak gravitational lensing in addition to type Ia supernovae. Its pixel scale has been set to 0.10 arcsec per pixel as established by the needs of supernova observations. To find the optimal pixel scale for accurate weak lensing measurements we conduct a tradeoff study in which, via simulations, we fix the suvey size in total pixels and vary the pixel scale. Our preliminary results show that with a smaller scale of about 0.08 arcsec per pixel we can minimize the contribution of intrinsic shear variance to the error on the power spectrum of mass density distortion. Currently we are testing the robustness of this figure as well as determining whether dithering yields analogous results.

  14. Importance and challenges of measuring intrinsic foot muscle strength

    PubMed Central

    2012-01-01

    Background Intrinsic foot muscle weakness has been implicated in a range of foot deformities and disorders. However, to establish a relationship between intrinsic muscle weakness and foot pathology, an objective measure of intrinsic muscle strength is needed. The aim of this review was to provide an overview of the anatomy and role of intrinsic foot muscles, implications of intrinsic weakness and evaluate the different methods used to measure intrinsic foot muscle strength. Method Literature was sourced from database searches of MEDLINE, PubMed, SCOPUS, Cochrane Library, PEDro and CINAHL up to June 2012. Results There is no widely accepted method of measuring intrinsic foot muscle strength. Methods to estimate toe flexor muscle strength include the paper grip test, plantar pressure, toe dynamometry, and the intrinsic positive test. Hand-held dynamometry has excellent interrater and intrarater reliability and limits toe curling, which is an action hypothesised to activate extrinsic toe flexor muscles. However, it is unclear whether any method can actually isolate intrinsic muscle strength. Also most methods measure only toe flexor strength and other actions such as toe extension and abduction have not been adequately assessed. Indirect methods to investigate intrinsic muscle structure and performance include CT, ultrasonography, MRI, EMG, and muscle biopsy. Indirect methods often discriminate between intrinsic and extrinsic muscles, but lack the ability to measure muscle force. Conclusions There are many challenges to accurately measure intrinsic muscle strength in isolation. Most studies have measured toe flexor strength as a surrogate measure of intrinsic muscle strength. Hand-held dynamometry appears to be a promising method of estimating intrinsic muscle strength. However, the contribution of extrinsic muscles cannot be excluded from toe flexor strength measurement. Future research should clarify the relative contribution of intrinsic and extrinsic muscles

  15. Prevalence of reduced muscle strength in older U.S. adults: United States, 2011-2012.

    PubMed

    Looker, Anne C; Wang, Chia-Yih

    2015-01-01

    Five percent of adults aged 60 and over had weak muscle strength and 13% had intermediate muscle strength, as defined by the new FNIH criteria. Weak muscle strength is clinically relevant because it is associated with slow gait speed, an important mobility impairment. It is also linked to an increased risk of death. The prevalence of reduced muscle strength increased with age and was higher in non-Hispanic Asian and Hispanic persons than in non-Hispanic white or non-Hispanic black persons. Decreasing muscle strength was linked with increased difficulty in rising from an armless chair, which is another important type of mobility impairment. PMID:25633238

  16. The Strength of the Metal. Aluminum Oxide Interface

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1984-01-01

    The strength of the interface between metals and aluminum oxide is an important factor in the successful operation of devices found throughout modern technology. One finds the interface in machine tools, jet engines, and microelectronic integrated circuits. The strength of the interface, however, should be strong or weak depending on the application. The diverse technological demands have led to some general ideas concerning the origin of the interfacial strength, and have stimulated fundamental research on the problem. Present status of our understanding of the source of the strength of the metal - aluminum oxide interface in terms of interatomic bonds are reviewed. Some future directions for research are suggested.

  17. Studies of fiber-matrix adhesion on compression strength

    NASA Technical Reports Server (NTRS)

    Bascom, Willard D.; Nairn, John A.; Boll, D. J.

    1991-01-01

    A study was initiated on the effect of the matrix polymer and the fiber matrix bond strength of carbon fiber polymer matrix composites. The work includes tests with micro-composites, single ply composites, laminates, and multi-axial loaded cylinders. The results obtained thus far indicate that weak fiber-matrix adhesion dramatically reduces 0 degree compression strength. Evidence is also presented that the flaws in the carbon fiber that govern compression strength differ from those that determine fiber tensile strength. Examination of post-failure damage in the single ply tests indicates kink banding at the crack tip.

  18. Alumina fiber strength improvement

    NASA Technical Reports Server (NTRS)

    Pepper, R. T.; Nelson, D. C.

    1982-01-01

    The effective fiber strength of alumina fibers in an aluminum composite was increased to 173,000 psi. A high temperature heat treatment, combined with a glassy carbon surface coating, was used to prevent degradation and improve fiber tensile strength. Attempts to achieve chemical strengthening of the alumina fiber by chromium oxide and boron oxide coatings proved unsuccessful. A major problem encountered on the program was the low and inconsistent strength of the Dupont Fiber FP used for the investigation.

  19. Detecting weakly interacting massive particles.

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Gelmini, G. B.

    The growing synergy between astrophysics, particle physics, and low background experiments strengthens the possibility of detecting astrophysical non-baryonic matter. The idea of direct detection is that an incident, massive weakly interacting particle could collide with a nucleus and transfer an energy that could be measured. The present low levels of background achieved by the PNL/USC Ge detector represent a new technology which yields interesting bounds on Galactic cold dark matter and on light bosons emitted from the Sun. Further improvements require the development of cryogenic detectors. The authors analyse the practicality of such detectors, their optimalization and background suppression using the "annual modulation effect".

  20. Weak lensing by galaxy troughs

    NASA Astrophysics Data System (ADS)

    Gruen, Daniel

    2016-06-01

    Galaxy troughs, i.e. underdensities in the projected galaxy field, are a weak lensing probe of the low density Universe with high signal-to-noise ratio. I present measurements of the radial distortion of background galaxy images and the de-magnification of the CMB by troughs constructed from Dark Energy Survey and Sloan Digital Sky Survey galaxy catalogs. With high statistical significance and a relatively robust modeling, these probe gravity in regimes of density and scale difficult to access for conventional statistics.

  1. Weak quasielastic production of hyperons

    SciTech Connect

    Singh, S. K.; Vacas, M. J. Vicente

    2006-09-01

    The quasielastic weak production of {lambda} and {sigma} hyperons from nucleons and nuclei induced by antineutrinos is studied in the energy region of some ongoing neutrino oscillation experiments in the intermediate energy region. The hyperon-nucleon transition form factors determined from neutrino-nucleon scattering and an analysis of high precision data on semileptonic decays of neutron and hyperons using SU(3) symmetry have been used. The nuclear effects due to Fermi motion and final state interaction effects due to hyperon-nucleon scattering have also been studied. The numerical results for differential and total cross sections have been presented.

  2. Tagged-weak {pi} method

    SciTech Connect

    Margaryan, A.; Hashimoto, O.; Kakoyan, V.; Knyazyan, S.; Tang, L.

    2011-02-15

    A new 'tagged-weak {pi} method' is proposed for determination of electromagnetic transition probabilities B(E2) and B(M1) of the hypernuclear states with lifetimes of {approx}10{sup -10} s. With this method, we are planning to measure B(E2) and B(M1) for light hypernuclei at JLab. The results of Monte Carlo simulations for the case of E2(5/2{sup +}, 3/2{sup +} {yields} 1/2{sup +}) transitions in {sub {Lambda}}{sup 7}He hypernuclei are presented.

  3. Strength Training and Your Child

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Strength Training and Your Child KidsHealth > For Parents > Strength Training ... help prevent injuries and speed up recovery. About Strength Training Strength training is the practice of using free ...

  4. The weak scale from BBN

    NASA Astrophysics Data System (ADS)

    Hall, Lawrence J.; Pinner, David; Ruderman, Joshua T.

    2014-12-01

    The measured values of the weak scale, v, and the first generation masses, m u, d, e , are simultaneously explained in the multiverse, with all these parameters scanning independently. At the same time, several remarkable coincidences are understood. Small variations in these parameters away from their measured values lead to the instability of hydrogen, the instability of heavy nuclei, and either a hydrogen or a helium dominated universe from Big Bang Nucleosynthesis. In the 4d parameter space of ( m u , m d , m e , v), catastrophic boundaries are reached by separately increasing each parameter above its measured value by a factor of (1.4, 1.3, 2.5, ˜ 5), respectively. The fine-tuning problem of the weak scale in the Standard Model is solved: as v is increased beyond the observed value, it is impossible to maintain a significant cosmological hydrogen abundance for any values of m u, d, e that yield both hydrogen and heavy nuclei stability.

  5. Weak antilocalisation in topological insulators

    NASA Astrophysics Data System (ADS)

    Bi, Xintao; Hankiewicz, Ewelina; Culcer, Dimitrie

    2014-03-01

    Topological insulators (TI) have changed our understanding of insulating behaviour. They are insulators in the bulk but conducting along their surfaces due to spin-orbit interaction. Much of the recent research focuses on overcoming the transport bottleneck, the fact that surface state transport is overwhelmed by bulk transport stemming from unintentional doping. The key to overcoming this bottleneck is identifying unambiguous signatures of surface state transport. This talk will discuss one such signature, which is manifest in the coherent backscattering of electrons. Due to strong spin-orbit coupling in TI one expects to observe weak antilocalisation rather than weak localisation, meaning that coherent backscattering increases the electrical conductivity. The features of this effect, however, are rather subtle, because in TI the impurities have strong spin-orbit coupling as well. I will show that spin-orbit coupled impurities introduce an additional time scale, which is expected to be shorter than the dephasing time, and the resulting conductivity has a logarithmic dependence on the carrier density, a behaviour hitherto unknown in 2D electron systems. The result we predict is observable experimentally and would provide a smoking gun test of surface transport.

  6. Weak lensing and cosmological investigation

    NASA Astrophysics Data System (ADS)

    Acquaviva, Viviana

    2005-03-01

    In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the Cosmic Microwave Background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l ~= 1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended theories of gravity, introducing the physical observables suitable to cast the bridge between lensing and cosmology, and then evaluate the amplitude of the expected effect in the particular case of a Non-Minimally-Coupled model, featuring a quadratic coupling between quintessence and Ricci scalar.

  7. Building on Our Strengths.

    ERIC Educational Resources Information Center

    Hill, Robert

    1978-01-01

    Comments on the feeling that the American family is disintegrating, and that many criticisms traditionally made about Black families are now made about White families. Suggests that people need to stress family strengths. As an example, five major strengths of Black families are described: flexibility, work and achievement ethics, religiosity, and…

  8. Strengths of Remarried Families.

    ERIC Educational Resources Information Center

    Knaub, Patricia Kain; And Others

    1984-01-01

    Focuses on remarried families' (N=80) perceptions of family strengths, marital satisfaction, and adjustment to the remarried situation. Results indicated that although most would like to make some changes, scores on the measurements used were high. A supportive environment was the most important predictor of family strength and success. (JAC)

  9. Tips from the toolkit: 2--assessing organisational strengths.

    PubMed

    Steer, Neville

    2010-03-01

    'SWOT' is a familiar term used in the development of business strategy. It is based on the identification of strengths, weaknesses, opportunities and threats as part of a strategic analysis approach. While there are a range of more sophisticated models for analysing and developing business strategy, it is a useful model for general practice as it is less time consuming than other approaches. The following article discusses some ways to apply this framework to assess organisational strengths (and weaknesses). It is based on The Royal Australian College of General Practitioners' "General practice management toolkit".

  10. Strengths of serpentinite gouges at elevated temperatures

    USGS Publications Warehouse

    Moore, Diane E.; Lockner, D.A.; Ma, S.; Summers, R.; Byerlee, J.D.

    1997-01-01

    Serpentinite has been proposed as a cause of both low strength and aseismic creep of fault zones. To test these hypotheses, we have measured the strength of chrysotile-, lizardite-, and antigorite-rich serpentinite gouges under hydrothermal conditions, with emphasis on chrysotile, which has thus far received little attention. At 25??C, the coefficient of friction, ??, of chrysotile gouge is roughly 0.2, whereas the lizardite- and antigorite-rich gouges are at least twice as strong. The very low room temperature strength of chrysotile is a consequence of its unusually high adsorbed water content. When the adsorbed water is removed, chrysotile is as strong as pure antigorite gouge at room temperature. Heating to ???200??C causes the frictional strengths of all three gouges to increase. Limited data suggest that different polytypes of a given serpentine mineral have similar strengths; thus deformation-induced changes in polytype should not affect fault strength. At 25??C, the chrysotile gouge has a transition from velocity strengthening at low velocities to velocity weakening at high velocities, consistent with previous studies. At temperatures up to ???200??C, however, chrysotile strength is essentially independent of velocity at low velocities. Overall, chrysotile has a restricted range of velocity-strengthening behavior that migrates to higher velocities with increasing temperature. Less information on velocity dependence is available for the lizardite and antigorite gouges, but their behavior is consistent with that outlined for chrysotile. The marked changes in velocity dependence and strength of chrysotile with heating underscore the hazards of using room temperature data to predict fault behavior at depth. The velocity behavior at elevated temperatures does not rule out serpentinite as a cause of aseismic slip, but in the presence of a hydrostatic fluid pressure gradient, all varieties of serpentine are too strong to explain the apparent weakness of faults such

  11. Revealing geometric phases in modular and weak values with a quantum eraser

    NASA Astrophysics Data System (ADS)

    Cormann, Mirko; Remy, Mathilde; Kolaric, Branko; Caudano, Yves

    2016-04-01

    We present a procedure to completely determine the complex modular values of arbitrary observables of pre- and postselected ensembles, which works experimentally for all measurement strengths and all postselected states. This procedure allows us to discuss the physics of modular and weak values in interferometric experiments involving a qubit meter. We determine both the modulus and the argument of the modular value for any measurement strength in a single step, by simultaneously controlling the visibility and the phase in a quantum eraser interference experiment. Modular and weak values are closely related. Using entangled qubits for the probed and meter systems, we show that the phase of the modular and weak values has a topological origin. This phase is completely defined by the intrinsic physical properties of the probed system and its time evolution. The physical significance of this phase can thus be used to evaluate the quantumness of weak values.

  12. Dynamic strength of molecular adhesion bonds.

    PubMed Central

    Evans, E; Ritchie, K

    1997-01-01

    In biology, molecular linkages at, within, and beneath cell interfaces arise mainly from weak noncovalent interactions. These bonds will fail under any level of pulling force if held for sufficient time. Thus, when tested with ultrasensitive force probes, we expect cohesive material strength and strength of adhesion at interfaces to be time- and loading rate-dependent properties. To examine what can be learned from measurements of bond strength, we have extended Kramers' theory for reaction kinetics in liquids to bond dissociation under force and tested the predictions by smart Monte Carlo (Brownian dynamics) simulations of bond rupture. By definition, bond strength is the force that produces the most frequent failure in repeated tests of breakage, i.e., the peak in the distribution of rupture forces. As verified by the simulations, theory shows that bond strength progresses through three dynamic regimes of loading rate. First, bond strength emerges at a critical rate of loading (> or = 0) at which spontaneous dissociation is just frequent enough to keep the distribution peak at zero force. In the slow-loading regime immediately above the critical rate, strength grows as a weak power of loading rate and reflects initial coupling of force to the bonding potential. At higher rates, there is crossover to a fast regime in which strength continues to increase as the logarithm of the loading rate over many decades independent of the type of attraction. Finally, at ultrafast loading rates approaching the domain of molecular dynamics simulations, the bonding potential is quickly overwhelmed by the rapidly increasing force, so that only naked frictional drag on the structure remains to retard separation. Hence, to expose the energy landscape that governs bond strength, molecular adhesion forces must be examined over an enormous span of time scales. However, a significant gap exists between the time domain of force measurements in the laboratory and the extremely fast scale

  13. Lizard locomotion on weak sand

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel

    2005-03-01

    Terrestrial animal locomotion in the natural world can involve complex foot-ground interaction; for example, running on sand probes the solid and fluid behaviors of the medium. We study locomotion of desert-dwelling lizard Callisaurus draconoides (length 16 cm, mass=20 g) during rapid running on sand. To explore the role of foot-ground interaction on locomotion, we study the impact of flat disks ( 2 cm diameter, 10 grams) into a deep (800 particle diameters) bed of 250 μm glass spheres of fixed volume fraction φ 0.59, and use a vertical flow of air (a fluidized bed) to change the material properties of the medium. A constant flow Q below the onset of bed fluidization weakens the solid: at fixed φ the penetration depth and time of a disk increases with increasing Q. We measure the average speed, foot impact depth, and foot contact time as a function of material strength. The animal maintains constant penetration time (30 msec) and high speed (1.4 m/sec) even when foot penetration depth varies as we manipulate material strength. The animals compensate for decreasing propulsion by increasing stride frequency.

  14. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.894 Weak. Weak means... content, inferior flavor, or are of poor keeping quality....

  15. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.894 Weak. Weak means that individual berries are somewhat translucent, watery and soft, may have relatively low...

  16. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.894 Weak. Weak means that individual berries are somewhat translucent, watery and soft, may have relatively low...

  17. Migrant networks and international migration: testing weak ties.

    PubMed

    Liu, Mao-Mei

    2013-08-01

    This article examines the role of migrant social networks in international migration and extends prior research by testing the strength of tie theory, decomposing networks by sources and resources, and disentangling network effects from complementary explanations. Nearly all previous empirical research has ignored friendship ties and has largely neglected extended-family ties. Using longitudinal data from the Migration between Africa and Europe project collected in Africa (Senegal) and Europe (France, Italy, and Spain), this article tests the robustness of network theory-and in particular, the role of weak ties-on first-time migration between Senegal and Europe. Discrete-time hazard model results confirm that weak ties are important and that network influences appear to be gendered, but they do not uphold the contention in previous literature that strong ties are more important than weak ties for male and female migration. Indeed, weak ties play an especially important role in male migration. In terms of network resources, having more resources as a result of strong ties appears to dampen overall migration, while having more resources as a result of weaker ties appears to stimulate male migration. Finally, the diversity of resources has varied effects for male and female migration.

  18. Breaking through barriers: using technology to address executive function weaknesses and improve student achievement.

    PubMed

    Schwartz, David M

    2014-01-01

    Assistive technologies provide significant capabilities for improving student achievement. Improved accessibility, cost, and diversity of applications make integration of technology a powerful tool to compensate for executive function weaknesses and deficits and their impact on student performance, learning, and achievement. These tools can be used to compensate for decreased working memory, poor time management, poor planning and organization, poor initiation, and decreased memory. Assistive technology provides mechanisms to assist students with diverse strengths and weaknesses in mastering core curricular concepts. PMID:25010083

  19. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere

    PubMed Central

    Zhang, T. L.; Baumjohann, W.; Russell, C. T.; Luhmann, J. G.; Xiao, S. D.

    2016-01-01

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth’s twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander. PMID:27009234

  20. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Tielong; Baumjohann, Wolfgang; Russell, Christopher; Luhmann, Janet

    2016-04-01

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth's twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander.

  1. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Zhang, T. L.; Baumjohann, W.; Russell, C. T.; Luhmann, J. G.; Xiao, S. D.

    2016-03-01

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth’s twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander.

  2. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere.

    PubMed

    Zhang, T L; Baumjohann, W; Russell, C T; Luhmann, J G; Xiao, S D

    2016-01-01

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth's twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander. PMID:27009234

  3. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere.

    PubMed

    Zhang, T L; Baumjohann, W; Russell, C T; Luhmann, J G; Xiao, S D

    2016-03-24

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth's twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander.

  4. Deterministic weak localization in periodic structures.

    PubMed

    Tian, C; Larkin, A

    2005-12-01

    In some perfect periodic structures classical motion exhibits deterministic diffusion. For such systems we present the weak localization theory. As a manifestation for the velocity autocorrelation function a universal power law decay is predicted to appear at four Ehrenfest times. This deterministic weak localization is robust against weak quenched disorders, which may be confirmed by coherent backscattering measurements of periodic photonic crystals.

  5. Crew Strength Training

    NASA Video Gallery

    Train to develop your upper and lower body strength in your muscles and bones by performing body-weight squats and push-ups.The Train Like an Astronaut project uses the excitement of exploration to...

  6. Developing Strengths in Families

    ERIC Educational Resources Information Center

    Bowman, Ted

    1976-01-01

    There are few descriptions of growth experiences for total families. This paper describes one such model. It expresses the conviction that families need opportunities to come together with other families to identify strengths, sharpen communication skills, and establish goals. (Author)

  7. Protecting weak measurements against systematic errors

    NASA Astrophysics Data System (ADS)

    Pang, Shengshi; Alonso, Jose Raul Gonzalez; Brun, Todd A.; Jordan, Andrew N.

    2016-07-01

    In this work, we consider the systematic error of quantum metrology by weak measurements under decoherence. We derive the systematic error of maximum likelihood estimation in general to the first-order approximation of a small deviation in the probability distribution and study the robustness of standard weak measurement and postselected weak measurements against systematic errors. We show that, with a large weak value, the systematic error of a postselected weak measurement when the probe undergoes decoherence can be significantly lower than that of a standard weak measurement. This indicates another advantage of weak-value amplification in improving the performance of parameter estimation. We illustrate the results by an exact numerical simulation of decoherence arising from a bosonic mode and compare it to the first-order analytical result we obtain.

  8. Fast Learning with Weak Synaptic Plasticity.

    PubMed

    Yger, Pierre; Stimberg, Marcel; Brette, Romain

    2015-09-30

    New sensory stimuli can be learned with a single or a few presentations. Similarly, the responses of cortical neurons to a stimulus have been shown to increase reliably after just a few repetitions. Long-term memory is thought to be mediated by synaptic plasticity, but in vitro experiments in cortical cells typically show very small changes in synaptic strength after a pair of presynaptic and postsynaptic spikes. Thus, it is traditionally thought that fast learning requires stronger synaptic changes, possibly because of neuromodulation. Here we show theoretically that weak synaptic plasticity can, in fact, support fast learning, because of the large number of synapses N onto a cortical neuron. In the fluctuation-driven regime characteristic of cortical neurons in vivo, the size of membrane potential fluctuations grows only as √N, whereas a single output spike leads to potentiation of a number of synapses proportional to N. Therefore, the relative effect of a single spike on synaptic potentiation grows as √N. This leverage effect requires precise spike timing. Thus, the large number of synapses onto cortical neurons allows fast learning with very small synaptic changes. Significance statement: Long-term memory is thought to rely on the strengthening of coactive synapses. This physiological mechanism is generally considered to be very gradual, and yet new sensory stimuli can be learned with just a few presentations. Here we show theoretically that this apparent paradox can be solved when there is a tight balance between excitatory and inhibitory input. In this case, small synaptic modifications applied to the many synapses onto a given neuron disrupt that balance and produce a large effect even for modifications induced by a single stimulus. This effect makes fast learning possible with small synaptic changes and reconciles physiological and behavioral observations.

  9. A Universe without Weak Interactions

    SciTech Connect

    Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2006-04-07

    A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''Weakless Universe'' is matched to our Universe by simultaneously adjusting Standard Model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the Weakless Universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multi-parameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe.

  10. Weak Turbulence in Radiation Belts

    NASA Astrophysics Data System (ADS)

    Ganguli, Gurudas; Crabtree, Chris; Rudakov, Leonid

    2015-11-01

    Weak turbulence plays a significant role in space plasma dynamics. Induced nonlinear scattering dominates the evolution in the low-beta isothermal radiation belt plasmas and affects the propagation characteristics of waves. As whistler waves propagate away from the earth they are scattered in the magnetosphere such that their trajectories are turned earthward where they are reflected back towards the magnetosphere. Repeated scattering and reflection of the whistlers establishes a cavity in which the wave energy can be maintained for a long duration with, on average, a smaller wave-normal angle. Consequently, the cyclotron resonance time for the trapped energetic electrons increases, leading to an enhanced pitch-angle scattering rate. Enhanced pitch-angle scattering lowers the lifetime of the energetic electron population. Also, pitch-angle scattering of the trapped population in the cavity with a loss cone distribution amplifies the whistler waves, which in turn promotes a more rapid precipitation through a positive feedback mechanism. Typical storm-pumped radiation belt parameters and laboratory experiments will be used to elucidate this phenomenon Work supported by NRL Base Funds.

  11. Weak Turbulence in Radiation Belts

    NASA Astrophysics Data System (ADS)

    Ganguli, G.; Crabtree, C. E.; Rudakov, L.

    2015-12-01

    Weak turbulence plays a significant role in space plasma dynamics. Induced nonlinear scattering dominates the evolution in the low-beta isothermal radiation belt plasmas and affects the propagation characteristics of waves. As whistler waves propagate away from the earth they are scattered in the magnetosphere such that their trajectories are turned earthward where they are reflected back towards the magnetosphere. Repeated scattering and reflection of the whistlers establishes a cavity in which the wave energy can be maintained for a long duration with, on average, a smaller wave-normal angle. Consequently, the cyclotron resonance time for the trapped energetic electrons increases, leading to an enhanced pitch-angle scattering rate. Enhanced pitch-angle scattering lowers the lifetime of the energetic electron population. Also, pitch-angle scattering of the trapped population in the cavity with a loss cone distribution amplifies the whistler waves, which in turn promotes a more rapid precipitation through a positive feedback mechanism. Typical storm-pumped radiation belt parameters and laboratory experiments will be used to elucidate this phenomenon.

  12. Violation of the Leggett–Garg inequality with weak measurements of photons

    PubMed Central

    Goggin, M. E.; Almeida, M. P.; Barbieri, M.; Lanyon, B. P.; O’Brien, J. L.; White, A. G.; Pryde, G. J.

    2011-01-01

    By weakly measuring the polarization of a photon between two strong polarization measurements, we experimentally investigate the correlation between the appearance of anomalous values in quantum weak measurements and the violation of realism and nonintrusiveness of measurements. A quantitative formulation of the latter concept is expressed in terms of a Leggett–Garg inequality for the outcomes of subsequent measurements of an individual quantum system. We experimentally violate the Leggett–Garg inequality for several measurement strengths. Furthermore, we experimentally demonstrate that there is a one-to-one correlation between achieving strange weak values and violating the Leggett–Garg inequality. PMID:21220296

  13. Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis.

    PubMed

    Keller, Jennifer L; Fritz, Nora; Chiang, Chen Chun; Jiang, Allen; Thompson, Tziporah; Cornet, Nicole; Newsome, Scott D; Calabresi, Peter A; Zackowski, Kathleen

    2016-01-01

    Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can improve strength in individuals with MS, however; it remains unclear the duration of RST that is needed to make strength gains and how to adapt hip strengthening exercises for individuals of varying strength using only resistance bands. This paper describes the methodology to set up and implement an adapted resistance strength training program, using resistance bands, for individuals with MS. Directions for pre- and post-strength tests to evaluate efficacy of the strength-training program are included. Safety features and detailed instructions outline the weekly program content and progression. Current evidence is presented showing that significant strength gains can be made within 8 weeks of starting a RST program. Evidence is also presented showing that resistance strength training can be successfully adapted for individuals with MS of varying strength with little equipment. PMID:26863451

  14. Distribution and severity of weakness among patients with polymyositis, dermatomyositis and juvenile dermatomyositis

    PubMed Central

    Harris-Love, M. O.; Shrader, J. A.; Koziol, D.; Pahlajani, N.; Jain, M.; Smith, M.; Cintas, H. L.; McGarvey, C. L.; James-Newton, L.; Pokrovnichka, A.; Moini, B.; Cabalar, I.; Lovell, D. J.; Wesley, R.; Plotz, P. H.; Miller, F. W.; Hicks, J. E.

    2009-01-01

    Objective. To describe the distribution and severity of muscle weakness using manual muscle testing (MMT) in 172 patients with PM, DM and juvenile DM (JDM). The secondary objectives included characterizing individual muscle group weakness and determining associations of weakness with functional status and myositis characteristics in this large cohort of patients with myositis. Methods. Strength was assessed for 13 muscle groups using the 10-point MMT and expressed as a total score, subscores based on functional and anatomical regions, and grades for individual muscle groups. Patient characteristics and secondary outcomes, such as clinical course, muscle enzymes, corticosteroid dosage and functional status were evaluated for association with strength using univariate and multivariate analyses. Results. A gradient of proximal weakness was seen, with PM weakest, DM intermediate and JDM strongest among the three myositis clinical groups (P ≤ 0.05). Hip flexors, hip extensors, hip abductors, neck flexors and shoulder abductors were the muscle groups with the greatest weakness among all three clinical groups. Muscle groups were affected symmetrically. Conclusions. Axial and proximal muscle impairment was reflected in the five weakest muscles shared by our cohort of myositis patients. However, differences in the pattern of weakness were observed among all three clinical groups. Our findings suggest a greater severity of proximal weakness in PM in comparison with DM. PMID:19074186

  15. Tie strength distribution in scientific collaboration networks

    NASA Astrophysics Data System (ADS)

    Ke, Qing; Ahn, Yong-Yeol

    2014-09-01

    Science is increasingly dominated by teams. Understanding patterns of scientific collaboration and their impacts on the productivity and evolution of disciplines is crucial to understand scientific processes. Electronic bibliography offers a unique opportunity to map and investigate the nature of scientific collaboration. Recent studies have demonstrated a counterintuitive organizational pattern of scientific collaboration networks: densely interconnected local clusters consist of weak ties, whereas strong ties play the role of connecting different clusters. This pattern contrasts itself from many other types of networks where strong ties form communities while weak ties connect different communities. Although there are many models for collaboration networks, no model reproduces this pattern. In this paper, we present an evolution model of collaboration networks, which reproduces many properties of real-world collaboration networks, including the organization of tie strengths, skewed degree and weight distribution, high clustering, and assortative mixing.

  16. 21 CFR 524.1465 - Mupirocin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... infections of the skin, including superficial pyoderma, caused by susceptible strains of Staphylococcus aureus and S. intermedius. (3) Limitations. Federal law restricts this drug to use by or on the order...

  17. Pixelation Effects in Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. William; Rhodes, Jason; Massey, Richard; Ellis, Richard

    2007-11-01

    Weak gravitational lensing can be used to investigate both dark matter and dark energy but requires accurate measurements of the shapes of faint, distant galaxies. Such measurements are hindered by the finite resolution and pixel scale of digital cameras. We investigate the optimum choice of pixel scale for a space-based mission, using the engineering model and survey strategy of the proposed Supernova Acceleration Probe as a baseline. We do this by simulating realistic astronomical images containing a known input shear signal and then attempting to recover the signal using the Rhodes, Refregier, & Groth algorithm. We find that the quality of shear measurement is always improved by smaller pixels. However, in practice, telescopes are usually limited to a finite number of pixels and operational life span, so the total area of a survey increases with pixel size. We therefore fix the survey lifetime and the number of pixels in the focal plane while varying the pixel scale, thereby effectively varying the survey size. In a pure trade-off for image resolution versus survey area, we find that measurements of the matter power spectrum would have minimum statistical error with a pixel scale of 0.09" for a 0.14" FWHM point-spread function (PSF). The pixel scale could be increased to ~0.16" if images dithered by exactly half-pixel offsets were always available. Some of our results do depend on our adopted shape measurement method and should be regarded as an upper limit: future pipelines may require smaller pixels to overcome systematic floors not yet accessible, and, in certain circumstances, measuring the shape of the PSF might be more difficult than those of galaxies. However, the relative trends in our analysis are robust, especially those of the surface density of resolved galaxies. Our approach thus provides a snapshot of potential in available technology, and a practical counterpart to analytic studies of pixelation, which necessarily assume an idealized shape

  18. Weak {}^* convergence of operator means

    NASA Astrophysics Data System (ADS)

    Romanov, Alexandr V.

    2011-12-01

    For a linear operator U with \\Vert U^n\\Vert \\le \\operatorname{const} on a Banach space X we discuss conditions for the convergence of ergodic operator nets T_\\alpha corresponding to the adjoint operator U^* of U in the {W^*O}-topology of the space \\operatorname{End} X^*. The accumulation points of all possible nets of this kind form a compact convex set L in \\operatorname{End} X^*, which is the kernel of the operator semigroup G=\\overline{\\operatorname{co}}\\,\\Gamma_0, where \\Gamma_0=\\{U_n^*, n \\ge 0\\}. It is proved that all ergodic nets T_\\alpha weakly {}^* converge if and only if the kernel L consists of a single element. In the case of X=C(\\Omega) and the shift operator U generated by a continuous transformation \\varphi of a metrizable compactum \\Omega we trace the relationships among the ergodic properties of U, the structure of the operator semigroups L, G and \\Gamma=\\overline{\\Gamma}_0, and the dynamical characteristics of the semi-cascade (\\varphi,\\Omega). In particular, if \\operatorname{card}L=1, then a) for any \\omega \\in\\Omega the closure of the trajectory \\{\\varphi^n\\omega, n \\ge 0\\} contains precisely one minimal set m, and b) the restriction (\\varphi,m) is strictly ergodic. Condition a) implies the {W^*O}-convergence of any ergodic sequence of operators T_n \\in \\operatorname{End} X^* under the additional assumption that the kernel of the enveloping semigroup E(\\varphi,\\Omega) contains elements obtained from the `basis' family of transformations \\{\\varphi^n, n \\ge 0\\} of the compact set \\Omega by using some transfinite sequence of sequential passages to the limit.

  19. The Composite Direct Product Model: Strengths, Limitations, and New Approaches.

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Grayson, David

    The multitrait-multimethod (MTMM) paradigm is used widely to assess construct validity, but D. A. Kenny and D. A. Kashy (1992) lament that even after 30 years we still do not know how to analyze MTMM data. The Composite Direct Product (CDP) model has recently attracted considerable attention. Its strengths and weaknesses are evaluated, and a…

  20. Physical adsorption strength in open systems.

    PubMed

    Knippenberg, M Todd; Stuart, Steven J; Cooper, Alan C; Pez, G P; Cheng, Hansong

    2006-11-23

    For a physical adsorption system, the distances of adsorbates from the surface of a substrate can vary significantly, depending on particle loading and interatomic interactions. Although the total adsorption energy is quantified easily, the normalized, per-particle adsorption energies are more ambiguous if some of these particles are far away from the surface and are interacting only weakly with the substrate. A simple analytical procedure is proposed to characterize the distance dependence of the physisorption strength and effective adsorption capacity. As an example, the method is utilized to describe H2 physisorption in a finite bundle of single-walled carbon nanotubes. PMID:17107125

  1. Tongue weakness and somatosensory disturbance following oral endotracheal extubation.

    PubMed

    Su, Han; Hsiao, Tzu-Yu; Ku, Shih-Chi; Wang, Tyng-Guey; Lee, Jang-Jaer; Tzeng, Wen-Chii; Huang, Guan-Hua; Chen, Cheryl Chia-Hui

    2015-04-01

    The tongue plays important roles in mastication, swallowing, and speech, but its sensorimotor function might be affected by endotracheal intubation. The objective of this pilot study was to describe disturbances in the sensorimotor functions of the tongue over 14 days following oral endotracheal extubation. We examined 30 post-extubated patients who had prolonged (≥48 h) oral endotracheal intubation from six medical intensive care units. Another 36 patients were recruited and examined from dental and geriatric outpatient clinics served as a comparison group. Tongue strength was measured by the Iowa Oral Performance Instrument. Sensory disturbance of the tongue was measured by evaluating light touch sensation, oral stereognosis, and two-point discrimination with standardized protocols. Measurements were taken at three time points (within 48 h, and 7 and 14 days post-extubation) for patients with oral intubation but only once for the comparison group. The results show that independent of age, gender, tobacco used, and comorbidities, tongue strength was lower and its sensory functions were more impaired in patients who had oral intubation than in the comparison group. Sensory disturbances of the tongue gradually recovered, taking 14 days to be comparable with the comparison group, while weakness of the tongue persisted. In conclusion, patients with oral endotracheal intubation had weakness and somatosensory disturbances of the tongue lasting at least 14 days from extubation but whether is caused by intubation and whether is contributed to postextubation dysphagia should be further investigated.

  2. High strength alloys

    DOEpatents

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

    2010-08-31

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  3. High strength alloys

    DOEpatents

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  4. Spin resonance strength calculations

    SciTech Connect

    Courant,E.D.

    2008-10-06

    In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

  5. Instrumental systematics and weak gravitational lensing

    NASA Astrophysics Data System (ADS)

    Mandelbaum, R.

    2015-05-01

    We present a pedagogical review of the weak gravitational lensing measurement process and its connection to major scientific questions such as dark matter and dark energy. Then we describe common ways of parametrizing systematic errors and understanding how they affect weak lensing measurements. Finally, we discuss several instrumental systematics and how they fit into this context, and conclude with some future perspective on how progress can be made in understanding the impact of instrumental systematics on weak lensing measurements.

  6. Managing yourself. Stop overdoing your strengths.

    PubMed

    Kaplan, Robert E; Kaiser, Robert B

    2009-02-01

    Although most managers can recognize an off-kilter leader (consider the highly supportive boss who cuts people too much slack), it's quite difficult to see overkill in yourself. Unfortunately, that's where leadership development tools such as 360-degree surveys fail to deliver, say Kaplan and Kaiser. Dividing qualities into "strengths" and "weaknesses" and rating them on a five-point scale will not account for strengths overplayed. The authors suggest several strategies, based on their years of consulting experience and research, for figuring out which attributes you've employed to excess and adjusting your behavior accordingly. Strengths taken too far have two consequences: First, they become weaknesses. For instance, quick-wittedness can turn into impatience with others. Second, you're at risk of becoming extremely lopsided--that is, diminishing your capacity on the opposite pole. A leader who is very good at building consensus, for example, may take too long to move into action. To strike a balance between two key leadership dualities--forceful versus enabling, and strategic versus operational--you need to see your actions and motivations clearly. That's no easy task since most leadership development tools don't spell out that you're overdoing your strengths. But there are other ways to bring that information to light. You can start with a review of the highest ratings on your most recent 360 report. Ask yourself: Is this too much of a good thing? Another technique is to make a list of the traits you most want to have as a leader. Are you going to extremes with any of them? To check for lopsidedness, you can prompt feedback from other people with a list of qualities you've composed or one you've gleaned from other sources. Once you know which attributes you're overdoing, you can recalibrate. PMID:19266705

  7. Managing yourself. Stop overdoing your strengths.

    PubMed

    Kaplan, Robert E; Kaiser, Robert B

    2009-02-01

    Although most managers can recognize an off-kilter leader (consider the highly supportive boss who cuts people too much slack), it's quite difficult to see overkill in yourself. Unfortunately, that's where leadership development tools such as 360-degree surveys fail to deliver, say Kaplan and Kaiser. Dividing qualities into "strengths" and "weaknesses" and rating them on a five-point scale will not account for strengths overplayed. The authors suggest several strategies, based on their years of consulting experience and research, for figuring out which attributes you've employed to excess and adjusting your behavior accordingly. Strengths taken too far have two consequences: First, they become weaknesses. For instance, quick-wittedness can turn into impatience with others. Second, you're at risk of becoming extremely lopsided--that is, diminishing your capacity on the opposite pole. A leader who is very good at building consensus, for example, may take too long to move into action. To strike a balance between two key leadership dualities--forceful versus enabling, and strategic versus operational--you need to see your actions and motivations clearly. That's no easy task since most leadership development tools don't spell out that you're overdoing your strengths. But there are other ways to bring that information to light. You can start with a review of the highest ratings on your most recent 360 report. Ask yourself: Is this too much of a good thing? Another technique is to make a list of the traits you most want to have as a leader. Are you going to extremes with any of them? To check for lopsidedness, you can prompt feedback from other people with a list of qualities you've composed or one you've gleaned from other sources. Once you know which attributes you're overdoing, you can recalibrate.

  8. Functional organization of excitatory synaptic strength in primary visual cortex

    PubMed Central

    Muir, Dylan R.; Houlton, Rachael; Sader, Elie N.; Ko, Ho; Hofer, Sonja B.; Mrsic-Flogel, Thomas D.

    2016-01-01

    The strength of synaptic connections fundamentally determines how neurons influence each other’s firing. Excitatory connection amplitudes between pairs of cortical neurons vary over two orders of magnitude, comprising only very few strong connections among many weaker ones1–9. Although this highly skewed distribution of connection strengths is observed in diverse cortical areas1–9, its functional significance remains unknown: it is not clear how connection strength relates to neuronal response properties, nor how strong and weak inputs contribute to information processing in local microcircuits. Here we reveal that the strength of connections between layer 2/3 (L2/3) pyramidal neurons in mouse primary visual cortex (V1) obeys a simple rule—the few strong connections occur between neurons with most correlated responses, while only weak connections link neurons with uncorrelated responses. Moreover, we show that strong and reciprocal connections occur between cells with similar spatial receptive field structure. Although weak connections far outnumber strong connections, each neuron receives the majority of its local excitation from a small number of strong inputs provided by the few neurons with similar responses to visual features. By dominating recurrent excitation, these infrequent yet powerful inputs disproportionately contribute to feature preference and selectivity. Therefore, our results show that the apparently complex organization of excitatory connection strength reflects the similarity of neuronal responses, and suggest that rare, strong connections mediate stimulus-specific response amplification in cortical microcircuits. PMID:25652823

  9. Interaction of a weak discontinuity with elementary waves of Riemann problema)

    NASA Astrophysics Data System (ADS)

    Radha, R.; Sharma, V. D.

    2012-01-01

    We study the interaction of a weak discontinuity wave with the elementary waves of the Riemann problem for the one-dimensional Euler equations governing the flow of ideal polytropic gases, and investigate the effects of initial states, and the shock strength on the jumps in shock acceleration and the reflected and transmitted waves.

  10. Effect of bolting on roadway support in extremely weak rock.

    PubMed

    Li, Qinghai; Shi, Weiping; Qin, Zhongcheng

    2016-01-01

    In mine roadway support operations, floor bolting not only played a role in floor heave control, but also in reinforcing roof and its two sides. Correspondingly, bolting of roof and two sides also played a part in floor heave control. To quantify the effect of such bolting, based on roadway support in extremely weak rock, three physical models were produced and tested in laboratory. Through comparison of their displacements in three physical simulation experiments, the reinforcing effect of bolting in extremely weak rock roadways was quantified. Reinforcing coefficients was defined as displacement ratio between original support and new support regime. Results indicated that the reinforcing coefficients, for bolting of roof and its two sides, on floor, two sides, and roof reached 2.18, 3.56, and 1.81 respectively. The reinforcing coefficients for floor bolting on floor, two sides, and roof reached 3.06, 2.34, and 1.39 respectively. So in this extremely weak rock, the surrounding rock should be considered as an integral structure in any support operation: this allows for better local strength improvement, and provided future design guidance.

  11. Asymmetric Magnetic Reconnection in Weakly Ionized Chromospheric Plasmas

    NASA Astrophysics Data System (ADS)

    Murphy, Nicholas A.; Lukin, Vyacheslav S.

    2015-06-01

    Realistic models of magnetic reconnection in the solar chromosphere must take into account that the plasma is partially ionized and that plasma conditions within any two magnetic flux bundles undergoing reconnection may not be the same. Asymmetric reconnection in the chromosphere may occur when newly emerged flux interacts with pre-existing, overlying flux. We present 2.5D simulations of asymmetric reconnection in weakly ionized, reacting plasmas where the magnetic field strengths, ion and neutral densities, and temperatures are different in each upstream region. The plasma and neutral components are evolved separately to allow non-equilibrium ionization. As in previous simulations of chromospheric reconnection, the current sheet thins to the scale of the neutral–ion mean free path and the ion and neutral outflows are strongly coupled. However, the ion and neutral inflows are asymmetrically decoupled. In cases with magnetic asymmetry, a net flow of neutrals through the current sheet from the weak-field (high-density) upstream region into the strong-field upstream region results from a neutral pressure gradient. Consequently, neutrals dragged along with the outflow are more likely to originate from the weak-field region. The Hall effect leads to the development of a characteristic quadrupole magnetic field modified by asymmetry, but the X-point geometry expected during Hall reconnection does not occur. All simulations show the development of plasmoids after an initial laminar phase.

  12. Effect of bolting on roadway support in extremely weak rock.

    PubMed

    Li, Qinghai; Shi, Weiping; Qin, Zhongcheng

    2016-01-01

    In mine roadway support operations, floor bolting not only played a role in floor heave control, but also in reinforcing roof and its two sides. Correspondingly, bolting of roof and two sides also played a part in floor heave control. To quantify the effect of such bolting, based on roadway support in extremely weak rock, three physical models were produced and tested in laboratory. Through comparison of their displacements in three physical simulation experiments, the reinforcing effect of bolting in extremely weak rock roadways was quantified. Reinforcing coefficients was defined as displacement ratio between original support and new support regime. Results indicated that the reinforcing coefficients, for bolting of roof and its two sides, on floor, two sides, and roof reached 2.18, 3.56, and 1.81 respectively. The reinforcing coefficients for floor bolting on floor, two sides, and roof reached 3.06, 2.34, and 1.39 respectively. So in this extremely weak rock, the surrounding rock should be considered as an integral structure in any support operation: this allows for better local strength improvement, and provided future design guidance. PMID:27588248

  13. Limits on amplification by Aharonov-Albert-Vaidman weak measurement

    SciTech Connect

    Koike, Tatsuhiko; Tanaka, Saki

    2011-12-15

    We analyze the amplification by the Aharonov-Albert-Vaidman weak quantum measurement on a Sagnac interferometer [Dixon et al., Phys. Rev. Lett. 102, 173601 (2009)] up to all orders of the coupling strength between the measured system and the measuring device. The amplifier transforms a small tilt of a mirror into a large transverse displacement of the laser beam. The conventional analysis has shown that the measured value is proportional to the weak value, so that the amplification can be made arbitrarily large in the cost of decreasing output laser intensity. It is shown that the measured displacement and the amplification factor are in fact not proportional to the weak value and rather vanish in the limit of infinitesimal output intensity. We derive the optimal overlap of the pre- and postselected states with which the amplification become maximum. We also show that the nonlinear effects begin to arise in the performed experiments so that any improvements in the experiment, typically with an amplification greater than 100, should require the nonlinear theory in translating the observed value to the original displacement.

  14. Notch strength of composites

    NASA Technical Reports Server (NTRS)

    Whitney, J. M.

    1983-01-01

    The notch strength of composites is discussed. The point stress and average stress criteria relate the notched strength of a laminate to the average strength of a relatively long tensile coupon. Tests of notched specimens in which microstrain gages have been placed at or near the edges of the holes have measured strains much larger that those measured in an unnotched tensile coupon. Orthotropic stress concentration analyses of failed notched laminates have also indicated that failure occurred at strains much larger than those experienced on tensile coupons with normal gage lengths. This suggests that the high strains at the edge of a hole can be related to the very short length of fiber subjected to these strains. Lockheed has attempted to correlate a series of tests of several laminates with holes ranging from 0.19 to 0.50 in. Although the average stress criterion correlated well with test results for hole sizes equal to or greater than 0.50 in., it over-estimated the laminate strength in the range of hole sizes from 0.19 to 0.38 in. It thus appears that a theory is needed that is based on the mechanics of failure and is more generally applicable to the range of hole sizes and the varieties of laminates found in aircraft construction.

  15. High strength composites evaluation

    SciTech Connect

    Marten, S.M.

    1992-02-01

    A high-strength, thick-section, graphite/epoxy composite was identified. The purpose of this development effort was to evaluate candidate materials and provide LANL with engineering properties. Eight candidate materials (Samples 1000, 1100, 1200, 1300, 1400, 1500, 1600, and 1700) were chosen for evaluation. The Sample 1700 thermoplastic material was the strongest overall.

  16. Gender Differences in Strength.

    ERIC Educational Resources Information Center

    Heyward, Vivian H.; And Others

    1986-01-01

    This investigation examined gender differences of 103 physically active men and women in upper and lower body strength as a function of lean body weight and the distribution of muscle and subcutaneous fat in the upper and lower limbs. Results are discussed. (Author/MT)

  17. Spin-glass transition in geometrically frustrated antiferromagnets with weak disorder

    NASA Astrophysics Data System (ADS)

    Andreanov, A.; Chalker, J. T.; Saunders, T. E.; Sherrington, D.

    2010-01-01

    We study the effect in geometrically frustrated antiferromagnets of weak, random variations in the strength of exchange interactions. Without disorder the simplest classical models for these systems have macroscopically degenerate ground states, and this degeneracy may prevent ordering at any temperature. Weak exchange randomness favors a small subset of these ground states and induces a spin-glass transition at an ordering temperature determined by the amplitude of modulations in interaction strength. We use the replica approach to formulate a theory for this transition, showing that it falls into the same universality class as conventional spin-glass transitions. In addition, we show that a model with a low concentration of defect bonds can be mapped onto a system of randomly located pseudospins that have dipolar effective interactions. We also present detailed results from Monte Carlo simulations of the classical Heisenberg antiferromagnet on the pyrochlore lattice with weak randomness in nearest-neighbor exchange.

  18. Multifluid magnetohydrodynamics of weakly ionized plasmas

    NASA Astrophysics Data System (ADS)

    Menzel, Raymond

    show that the total electric field in the asteroid may either be of comparable strength to the electric field predicted by Sonett et al. or vanish depending on the magnetic field geometry. We include the effects of dust grains in the gas and calculate the heating rates in the plasma flow due to ion-neutral scattering and viscous dissipation. We term this newly discovered heating mechanism "electrodynamic heating", use measurements of asteroid electrical conductivities to estimate the upper limits of the possible heating rates and amount of thermal energy that can be deposited in the solid body, and compare these to the heating produced by the decay of radioactive nuclei like Al26. For the second problem we modeled molecular line emission from time-dependent multifluid MHD shock waves in star-forming regions. By incorporating realistic radiative cooling by CO and H2 into the numerical method developed by Ciolek & Roberge (2013), we present the only current models of truly time-dependent multifluid MHD shock waves in weakly-ionized plasmas. Using the physical conditions determined by our models, we present predictions of molecular emission in the form of excitation diagrams, which can be compared to observations of protostellar outflows in order to trace the physical conditions of these environments. Current work focuses on creating models for varying initial conditions and shock ages, which are and will be the subject of several in progress studies of observed molecular outflows and will provide further insight into the physics and chemistry of these flows.

  19. An assessment of the strengths and weaknesses of current veterinary systems in the developing world.

    PubMed

    Cheneau, Y; El Idrissi, A H; Ward, D

    2004-04-01

    The changes that veterinary services have undergone in the developing world over the last two decades are expected to continue and result in the further privatisation of selected tasks, the decentralisation of decision-making and a move towards more focus on public goods service delivery by State veterinary units. At the same time, global food consumption patterns are changing in numerous ways, which will certainly affect veterinary services delivery systems. These changes include a trend towards increasing globalisation, rapidly escalating consumer demand for animal protein, intensification of livestock production into larger units and growth of the trade of livestock and livestock products. Intensification of livestock production into larger units and global trade will increase the challenges resulting from the resurgence of serious animal diseases, food safety hazards and veterinary public health-related problems. Facing and managing these challenges raises issues related to animal health delivery systems and national policies that will have to be addressed. Strengthening the capacity of State veterinary units to respond to regulatory responsibilities dictated by national laws and international World Trade Organization and OIE (World organisation for animal health) health standards will be at the centre of animal health policies in most developing countries. Creating an environment which facilitates privatised service delivery and supports subcontracting is likely to contribute to improving economic efficiency and providing wider access to veterinary services. Equally important is the issue of professional development, which must be addressed by refocusing veterinary curricula and improving professional standards. The profession will then be in a better position to serve the needs of increasing numbers of consumers.

  20. Strengths and weakness of neuroscientific investigations of childhood poverty: future directions.

    PubMed

    Lipina, Sebastián J; Segretin, M Soledad

    2015-01-01

    The neuroscientific study of child poverty is a topic that has only recently emerged. In comparison with previous reviews (e.g., Hackman and Farah, 2009; Lipina and Colombo, 2009; Hackman et al., 2010; Raizada and Kishiyama, 2010; Lipina and Posner, 2012), our perspective synthesizes findings, and summarizes both conceptual and methodological contributions, as well as challenges that face current neuroscientific approaches to the study of childhood poverty. The aim of this effort is to identify target areas of study that could potentially help build a basic and applied research agenda for the coming years.

  1. An assessment of the strengths and weaknesses of current veterinary systems in the developing world.

    PubMed

    Cheneau, Y; El Idrissi, A H; Ward, D

    2004-04-01

    The changes that veterinary services have undergone in the developing world over the last two decades are expected to continue and result in the further privatisation of selected tasks, the decentralisation of decision-making and a move towards more focus on public goods service delivery by State veterinary units. At the same time, global food consumption patterns are changing in numerous ways, which will certainly affect veterinary services delivery systems. These changes include a trend towards increasing globalisation, rapidly escalating consumer demand for animal protein, intensification of livestock production into larger units and growth of the trade of livestock and livestock products. Intensification of livestock production into larger units and global trade will increase the challenges resulting from the resurgence of serious animal diseases, food safety hazards and veterinary public health-related problems. Facing and managing these challenges raises issues related to animal health delivery systems and national policies that will have to be addressed. Strengthening the capacity of State veterinary units to respond to regulatory responsibilities dictated by national laws and international World Trade Organization and OIE (World organisation for animal health) health standards will be at the centre of animal health policies in most developing countries. Creating an environment which facilitates privatised service delivery and supports subcontracting is likely to contribute to improving economic efficiency and providing wider access to veterinary services. Equally important is the issue of professional development, which must be addressed by refocusing veterinary curricula and improving professional standards. The profession will then be in a better position to serve the needs of increasing numbers of consumers. PMID:15200109

  2. The strengths and weaknesses of inverted pendulum models of human walking.

    PubMed

    McGrath, Michael; Howard, David; Baker, Richard

    2015-02-01

    An investigation into the kinematic and kinetic predictions of two "inverted pendulum" (IP) models of gait was undertaken. The first model consisted of a single leg, with anthropometrically correct mass and moment of inertia, and a point mass at the hip representing the rest of the body. A second model incorporating the physiological extension of a head-arms-trunk (HAT) segment, held upright by an actuated hip moment, was developed for comparison. Simulations were performed, using both models, and quantitatively compared with empirical gait data. There was little difference between the two models' predictions of kinematics and ground reaction force (GRF). The models agreed well with empirical data through mid-stance (20-40% of the gait cycle) suggesting that IP models adequately simulate this phase (mean error less than one standard deviation). IP models are not cyclic, however, and cannot adequately simulate double support and step-to-step transition. This is because the forces under both legs augment each other during double support to increase the vertical GRF. The incorporation of an actuated hip joint was the most novel change and added a new dimension to the classic IP model. The hip moment curve produced was similar to those measured during experimental walking trials. As a result, it was interpreted that the primary role of the hip musculature in stance is to keep the HAT upright. Careful consideration of the differences between the models throws light on what the different terms within the GRF equation truly represent.

  3. Identifying service quality strengths and weaknesses using SERVQUAL: a study of dental services.

    PubMed

    Kaldenberg, D; Becker, B W; Browne, B A; Browne, W G

    1997-01-01

    The goal of this study was to examine responses among dental patients to the most recent version of SERVQUAL, and to evaluate that instrument as a tool for measuring satisfaction in a dental practice. Items on the reliability and responsiveness dimensions produced the lowest satisfaction ratings, while improvements in providing services as promised and instilling confidence have the greatest potential for producing higher satisfaction among patients. Finally, using open-ended questions, we identified a number of patient events or experiences which caused either high or low scores on individual SERVQUAL items.

  4. Strengths and Weaknesses in Reading Skills of Youth with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Channell, Marie Moore; Loveall, Susan J.; Conners, Frances A.

    2013-01-01

    Reading-related skills of youth with intellectual disability (ID) were compared with those of typically developing (TD) children of similar verbal ability level. The group with ID scored lower than the TD group on word recognition and phonological decoding, but similarly on orthographic processing and rapid automatized naming (RAN). Further,…

  5. Strengths and weakness of neuroscientific investigations of childhood poverty: future directions

    PubMed Central

    Lipina, Sebastián J.; Segretin, M. Soledad

    2015-01-01

    The neuroscientific study of child poverty is a topic that has only recently emerged. In comparison with previous reviews (e.g., Hackman and Farah, 2009; Lipina and Colombo, 2009; Hackman et al., 2010; Raizada and Kishiyama, 2010; Lipina and Posner, 2012), our perspective synthesizes findings, and summarizes both conceptual and methodological contributions, as well as challenges that face current neuroscientific approaches to the study of childhood poverty. The aim of this effort is to identify target areas of study that could potentially help build a basic and applied research agenda for the coming years. PMID:25717299

  6. Understanding Learner Strengths and Weaknesses: Assessing Performance on an Integrated Writing Task

    ERIC Educational Resources Information Center

    Sawaki, Yasuyo; Quinlan, Thomas; Lee, Yong-Won

    2013-01-01

    The present study examined the factor structures across features of 446 examinees' responses to a writing task that integrates reading and listening modalities as well as reading and listening comprehension items of the TOEFL iBT[R] (Internet-based test). Both human and automated scores obtained for the integrated essays were utilized. Based on a…

  7. Strengths and Weaknesses in Executive Functioning in Children with Intellectual Disability

    ERIC Educational Resources Information Center

    Danielsson, Henrik; Henry, Lucy; Messer, David; Ronnberg, Jerker

    2012-01-01

    Children with intellectual disability (ID) were given a comprehensive range of executive functioning measures, which systematically varied in terms of verbal and non-verbal demands. Their performance was compared to the performance of groups matched on mental age (MA) and chronological age (CA), respectively. Twenty-two children were included in…

  8. Specific Learning Disability Identification: What Constitutes a Pattern of Strengths and Weaknesses?

    ERIC Educational Resources Information Center

    Schultz, Edward Karl; Simpson, Cynthia G.; Lynch, Sharon

    2012-01-01

    The 2004 Individuals with Disabilities Education Improvement Act (IDEA) and subsequent regulations published in 2006 have significantly changed the identification process for students suspected of having specific learning disabilities. Rather than using a discrepancy model contrasting intellectual and achievement test results, assessment…

  9. The Vienna Temperature Series: Strengths and weaknesses for the use in climate change analyses

    NASA Astrophysics Data System (ADS)

    Auer, I.; Böhm, R.; Gruber, C.; Jurković, A.

    2010-09-01

    Strakosch-Grassmann (1932*) reports about the first instrumental measurements in Vienna in 1697 for a span of eight months only. Later, continuous measurements have been carried out at the observatory of the Jesuit College since 1734, at the k.k. Universitätssternwarte (astronomical observatory of the University of Vienna) since 1762. Unfortunately, most of the data before 1775 have gone lost. The HISTALP (http://www.zamg.ac.at/histalp) temperature series of Vienna is a composite of Wien-Universitätssternwarte, Wien-Favoritenstraße und Wien-Hohe Warte. It allows studying climate variability for more than 235 years and it has been used very often in national and international studies. Although the Vienna series has been homogenized and quality checked with highest carefulness some remaining uncertainties are persisting. This especially concerns uncertainties of the very early measurements due to insufficient sheltering, and measurements of the last 60 years due to an increasing trend of the Viennese urban heat island. *Strakosch-Graßmann G, 1932. Neue Quellen zur Geschichte der Witterung in Europa vom 16. Bis zum 18. Jahrhundert. Met. Zeitschr. 1932, S 397.

  10. Religion as a Source of Strength or Weakness in Young Adult Literature.

    ERIC Educational Resources Information Center

    Fuchs, Lucy

    A survey of books for young people reveals that some of the best (and even award-winning) novels deal with the controversial issue of religion. Although most of these books deal with religion only in the background, some clearly present this issue in the forefront. One book, Cynthia Rylant's "A Fine White Dust" (1986), traces a religious quest. In…

  11. Strengths and Weaknesses of the Information Technology Curriculum in Library and Information Science Graduate Programs

    ERIC Educational Resources Information Center

    Singh, Vandana; Mehra, Bharat

    2013-01-01

    This research highlights the status of the information technology (IT) skills and competencies being taught at LIS schools in the United States. Results list specific IT topics that the library schools are teaching and the ones that are missing from the curriculum. Based on a literature review these skills are then juxtaposed with the expectations…

  12. Smaller Forbush Decreases in Solar Cycle 24: Effect of the Weak CME Field Strength?

    NASA Astrophysics Data System (ADS)

    Thakur, N.

    2015-12-01

    A Forbush decrease (FD) is a sudden depression in the intensity of galactic cosmic ray (GCR) background, followed by a gradual recovery. One of the major causes of FDs is the presence of magnetic structures such as magnetic clouds (MCs) or corotating interaction regions (CIRs) that have enhanced magnetic field, which can scatter particles away reducing the observed GCR intensity. Recent work (Gopalswamy et al. 2014, GRL 41, 2673) suggests that coronal mass ejections (CMEs) are expanding anomalously in solar cycle 24 due to the reduced total pressure in the ambient medium. One of the consequences of the anomalous expansion is the reduced magnetic content of MCs, so we expect subdued FDs in cycle 24. In this paper, we present preliminary results from a survey of FDs during MC events in cycle 24 in comparison with those in cycle 23. We find that only ~17% FDs in cycle 24 had an amplitude >3%, as compared to ~31% in cycle 23. This result is consistent with the difference in the maximum magnetic field intensities (Bmax) of MCs in the two cycles: only ~ 10% of MCs in cycle 24 have Bmax>20nT, compared to 22% in cycle 23, confirming that MCs of cycle 24 have weaker magnetic field content. Therefore, we suggest that weaker magnetic field intensity in the magnetic clouds of cycle 24 has led to FDs with smaller amplitudes.

  13. Perceptions of Online TESOL Teacher Education: Strengths, Weaknesses, Characteristics, and Effective Components

    ERIC Educational Resources Information Center

    Chen, Susan Tiffany

    2012-01-01

    Recent and ongoing expansion of online opportunities for teacher education and training continue in response to calls for better teacher preparation and professional development opportunities. However, with the introduction of online learning, the already controversial debate over educational technology has taken on a new dimension. Today's…

  14. Social Network Perspectives Reveal Strength of Academic Developers as Weak Ties

    ERIC Educational Resources Information Center

    Matthews, Kelly E.; Crampton, Andrea; Hill, Matthew; Johnson, Elizabeth D.; Sharma, Manjula D.; Varsavsky, Cristina

    2015-01-01

    Social network perspectives acknowledge the influence of disciplinary cultures on academics' teaching beliefs and practices with implications for academic developers. The contribution of academic developers in 18 scholarship of teaching and learning (SoTL) projects situated in the sciences are explored by drawing on data from a two-year national…

  15. Comparison of PubMed, Scopus, Web of Science, and Google Scholar: strengths and weaknesses.

    PubMed

    Falagas, Matthew E; Pitsouni, Eleni I; Malietzis, George A; Pappas, Georgios

    2008-02-01

    The evolution of the electronic age has led to the development of numerous medical databases on the World Wide Web, offering search facilities on a particular subject and the ability to perform citation analysis. We compared the content coverage and practical utility of PubMed, Scopus, Web of Science, and Google Scholar. The official Web pages of the databases were used to extract information on the range of journals covered, search facilities and restrictions, and update frequency. We used the example of a keyword search to evaluate the usefulness of these databases in biomedical information retrieval and a specific published article to evaluate their utility in performing citation analysis. All databases were practical in use and offered numerous search facilities. PubMed and Google Scholar are accessed for free. The keyword search with PubMed offers optimal update frequency and includes online early articles; other databases can rate articles by number of citations, as an index of importance. For citation analysis, Scopus offers about 20% more coverage than Web of Science, whereas Google Scholar offers results of inconsistent accuracy. PubMed remains an optimal tool in biomedical electronic research. Scopus covers a wider journal range, of help both in keyword searching and citation analysis, but it is currently limited to recent articles (published after 1995) compared with Web of Science. Google Scholar, as for the Web in general, can help in the retrieval of even the most obscure information but its use is marred by inadequate, less often updated, citation information.

  16. Internal Quality Assurance Systems in Portugal: What Their Strengths and Weaknesses Reveal

    ERIC Educational Resources Information Center

    Tavares, Orlanda; Sin, Cristina; Amaral, Alberto

    2016-01-01

    In Portugal, the agency for assessment and accreditation of higher education has recently included in its remit, beyond programme accreditation, the certification of internal quality assurance systems. This implies lighter touch accreditation and aims to direct institutions towards improvement, in addition to accountability. Twelve institutions…

  17. Integrating Social Networking Tools into ESL Writing Classroom: Strengths and Weaknesses

    ERIC Educational Resources Information Center

    Yunus, Melor Md; Salehi, Hadi; Chenzi, Chen

    2012-01-01

    With the rapid development of world and technology, English learning has become more important. Teachers frequently use teacher-centered pedagogy that leads to lack of interaction with students. This paper aims to investigate the advantages and disadvantages of integrating social networking tools into ESL writing classroom and discuss the ways to…

  18. Strategic marketing management for health management: cross impact matrix and TOWS (threats, opportunities, weaknesses, strengths).

    PubMed

    Proctor, T

    2000-01-01

    Organisations operate within a three-tiered environment--internal, micro and macro. The environment is a powerful force acting upon the effectiveness of strategic decision making. Failure to take cognisance of the influence of the three-tiered environment can have disastrous consequences. The cross-impact matrix and the TOWS matrix are two strategic decision-making aids that improve effective decision making. When used in conjunction with creative problem solving methods they can provide the basis of a powerful management tool.

  19. Young People's Satisfaction with Residential Care: Identifying Strengths and Weaknesses in Service Delivery

    ERIC Educational Resources Information Center

    Southwell, Jenni; Fraser, Elizabeth

    2010-01-01

    This paper presents findings from a landmark Australian study investigating the experiences and perspectives of young people in residential care. Data from a representative sample are analyzed to identify young people's satisfaction with various aspects of their residential care experience: their sense of safety, normality, support, comfort in…

  20. Commercial Crop Yields Reveal Strengths and Weaknesses for Organic Agriculture in the United States

    PubMed Central

    Savage, Steven D.; Jabbour, Randa

    2016-01-01

    Land area devoted to organic agriculture has increased steadily over the last 20 years in the United States, and elsewhere around the world. A primary criticism of organic agriculture is lower yield compared to non-organic systems. Previous analyses documenting the yield deficiency in organic production have relied mostly on data generated under experimental conditions, but these studies do not necessarily reflect the full range of innovation or practical limitations that are part of commercial agriculture. The analysis we present here offers a new perspective, based on organic yield data collected from over 10,000 organic farmers representing nearly 800,000 hectares of organic farmland. We used publicly available data from the United States Department of Agriculture to estimate yield differences between organic and conventional production methods for the 2014 production year. Similar to previous work, organic crop yields in our analysis were lower than conventional crop yields for most crops. Averaged across all crops, organic yield averaged 80% of conventional yield. However, several crops had no significant difference in yields between organic and conventional production, and organic yields surpassed conventional yields for some hay crops. The organic to conventional yield ratio varied widely among crops, and in some cases, among locations within a crop. For soybean (Glycine max) and potato (Solanum tuberosum), organic yield was more similar to conventional yield in states where conventional yield was greatest. The opposite trend was observed for barley (Hordeum vulgare), wheat (Triticum aestevum), and hay crops, however, suggesting the geographical yield potential has an inconsistent effect on the organic yield gap. PMID:27552217

  1. PS1-36: VDW Pharmacy File: Strengths, Weaknesses, and Recommendations

    PubMed Central

    Moore, Kristen M; Cheetham, T Craig; Dublin, Sascha; Hecht, Julia; Robinson, Scott; Brown, Jeffrey S

    2010-01-01

    Background: The HMO Research Network (HMORN) Virtual Data Warehouse (VDW) is a series of dataset standards and automated processes designed to facilitate the process of multisite research. It is virtual in that there is no centralized database; data continue to reside locally. Our objective was to assess the cross-site availability and completeness of the outpatient prescription dispensing or Pharmacy file. Methods: The VDW Pharmacy Working Group created a data checking plan to assess overall data availability and completeness of the Pharmacy file. A distributed SAS program was run at each HMORN site with a VDW Pharmacy file (n=11), with de-identified summary count data returned for analysis. The key Pharmacy file variables were National Drug Code (NDC), days supplied, and amount dispensed. NDCs were considered nonstandard for these reasons: not having exactly 11 digits; containing a character; or consisting of a single repeated number (e.g., 99999999999). For days supplied and amount dispensed, values of < 0, 0, > 500, or missing and values of < 0, 0, > 1000, or missing were considered out of typical range, respectively. Results: Eleven sites have Pharmacy data from 2000 June 2007; some have data going back more than 10 years. There were 61 million dispensings in 2007, with an average 5.1 million monthly dispensings among 2 million monthly users. Average monthly dispensings per user was 2.5, and the range across sites was 2.2–2.9. Across all sites from 2000–2007, < 0.1% and 0.3% of dispensings had a missing or nonstandard NDC, respectively; and 0.1% and 0.3% had days supplied and amount dispensed out of typical range, respectively. Few dispensings were for over-the-counter medications (5%), medical supplies (2%), or infusions (0.1%). 89% of elderly (age > 65) with a drug benefit had at least 1 annual dispensing (average monthly dispensings per user, 3.5), compared to 52% of those without a benefit (average, 3.2). Conclusions: The VDW Pharmacy file has good overall data quality, with few problems found, especially since 2000. Investigators can have confidence in the data in the Pharmacy file but may choose to limit studies to more recent years.

  2. Commercial Crop Yields Reveal Strengths and Weaknesses for Organic Agriculture in the United States.

    PubMed

    Kniss, Andrew R; Savage, Steven D; Jabbour, Randa

    2016-01-01

    Land area devoted to organic agriculture has increased steadily over the last 20 years in the United States, and elsewhere around the world. A primary criticism of organic agriculture is lower yield compared to non-organic systems. Previous analyses documenting the yield deficiency in organic production have relied mostly on data generated under experimental conditions, but these studies do not necessarily reflect the full range of innovation or practical limitations that are part of commercial agriculture. The analysis we present here offers a new perspective, based on organic yield data collected from over 10,000 organic farmers representing nearly 800,000 hectares of organic farmland. We used publicly available data from the United States Department of Agriculture to estimate yield differences between organic and conventional production methods for the 2014 production year. Similar to previous work, organic crop yields in our analysis were lower than conventional crop yields for most crops. Averaged across all crops, organic yield averaged 80% of conventional yield. However, several crops had no significant difference in yields between organic and conventional production, and organic yields surpassed conventional yields for some hay crops. The organic to conventional yield ratio varied widely among crops, and in some cases, among locations within a crop. For soybean (Glycine max) and potato (Solanum tuberosum), organic yield was more similar to conventional yield in states where conventional yield was greatest. The opposite trend was observed for barley (Hordeum vulgare), wheat (Triticum aestevum), and hay crops, however, suggesting the geographical yield potential has an inconsistent effect on the organic yield gap.

  3. Identifying service quality strengths and weaknesses using SERVQUAL: a study of dental services.

    PubMed

    Kaldenberg, D; Becker, B W; Browne, B A; Browne, W G

    1997-01-01

    The goal of this study was to examine responses among dental patients to the most recent version of SERVQUAL, and to evaluate that instrument as a tool for measuring satisfaction in a dental practice. Items on the reliability and responsiveness dimensions produced the lowest satisfaction ratings, while improvements in providing services as promised and instilling confidence have the greatest potential for producing higher satisfaction among patients. Finally, using open-ended questions, we identified a number of patient events or experiences which caused either high or low scores on individual SERVQUAL items. PMID:10179451

  4. Changing patterns of intellectual strengths and weaknesses in males with fragile X syndrome.

    PubMed

    Hodapp, R M; Dykens, E M; Ort, S I; Zelinsky, D G; Leckman, J F

    1991-12-01

    Examined the changing profiles of intelligence in males with fragile X syndrome as these individuals increased in chronological age. Using a psychometric instrument designed to measure styles of information processing, 21 males aged 4 to 27 years were examined cross-sectionally in sequential processing, simultaneous processing, and achievement. The age of the subject was associated with age-equivalent levels of both simultaneous processing and achievement, but fragile X males did not show higher levels of sequential processing with increasing chronological age. Compared to younger fragile X males, the older subjects were more delayed in sequential processing skills relative to their in other areas. A smaller longitudinal study confirmed the presence of a plateau in sequential processing among those subjects tested two times after the age of 10 years. Implications are discussed for diagnosis, intervention, and the matching of subject groups in mental retardation research.

  5. Commercial Crop Yields Reveal Strengths and Weaknesses for Organic Agriculture in the United States.

    PubMed

    Kniss, Andrew R; Savage, Steven D; Jabbour, Randa

    2016-01-01

    Land area devoted to organic agriculture has increased steadily over the last 20 years in the United States, and elsewhere around the world. A primary criticism of organic agriculture is lower yield compared to non-organic systems. Previous analyses documenting the yield deficiency in organic production have relied mostly on data generated under experimental conditions, but these studies do not necessarily reflect the full range of innovation or practical limitations that are part of commercial agriculture. The analysis we present here offers a new perspective, based on organic yield data collected from over 10,000 organic farmers representing nearly 800,000 hectares of organic farmland. We used publicly available data from the United States Department of Agriculture to estimate yield differences between organic and conventional production methods for the 2014 production year. Similar to previous work, organic crop yields in our analysis were lower than conventional crop yields for most crops. Averaged across all crops, organic yield averaged 80% of conventional yield. However, several crops had no significant difference in yields between organic and conventional production, and organic yields surpassed conventional yields for some hay crops. The organic to conventional yield ratio varied widely among crops, and in some cases, among locations within a crop. For soybean (Glycine max) and potato (Solanum tuberosum), organic yield was more similar to conventional yield in states where conventional yield was greatest. The opposite trend was observed for barley (Hordeum vulgare), wheat (Triticum aestevum), and hay crops, however, suggesting the geographical yield potential has an inconsistent effect on the organic yield gap. PMID:27552217

  6. Socio-Cognitive Understanding: A Strength or Weakness in Down's Syndrome?

    ERIC Educational Resources Information Center

    Wishart, J. G.

    2007-01-01

    Background: Social understanding is often thought to be relatively "protected" in children with Down's syndrome (DS) and to underlie the outgoing personality characteristically attributed to them. This paper draws together findings from our studies of behaviours during object concept testing, generally considered a theoretically "pure" measure of…

  7. Strengths and weaknesses in reading skills of youth with intellectual disabilities

    PubMed Central

    Channell, Marie Moore; Loveall, Susan J.; Conners, Frances A.

    2016-01-01

    Reading-related skills of youth with intellectual disability (ID) were compared with those of typically developing (TD) children of similar verbal ability level. The group with ID scored lower than the TD group on word recognition and phonological decoding, but similarly on orthographic processing and rapid automatized naming (RAN). Further, phonological decoding significantly mediated the relation between group membership and word recognition, whereas neither orthographic processing nor RAN did so. The group with ID also underperformed the TD group on phonological awareness and phonological memory, both of which significantly mediated the relation between group membership and phonological decoding. These data suggest that poor word recognition in youth with ID may be due largely to poor phonological decoding, which in turn may be due largely to poor phonological awareness and poor phonological memory. More focus on phonological skills in the classroom may help students with ID to develop better word recognition skills. PMID:23220054

  8. [Constructing the nursing profession from the perspective of gender. A weakness or strength?].

    PubMed

    Rodríguez García, Marta; Martínez Miguel, Esther; Tovar Reinoso, Alberto; González Hervias, Raquel; Goday Arean, Carmen; García Salinero, Julia

    2009-01-01

    To care for someone is a life-giving act whose existence goes so far back that it is lost in human memory. Despite the fact that the concept of health has evolved over the course of time, there is a constant factor, both in the social as in the practical context which ties care-giving implicitly to women. Innate qualities in the feminine sex, including vocation, kindness, dedication, softness, have contributed to undervalue professional work and to grant it little social recognition. As a group, nurses have been placed in the paradigm of oppression, due to the hierarchical vigilance medicine, a field located at the apex of power; has exercised over this profession. At present times, the humanization of caregiving and the role change by patients act favorably so that nurses begin to question the current situation their profession is in and to ask what can be done so their profession evolves independently

  9. The strengths and weaknesses of inverted pendulum models of human walking.

    PubMed

    McGrath, Michael; Howard, David; Baker, Richard

    2015-02-01

    An investigation into the kinematic and kinetic predictions of two "inverted pendulum" (IP) models of gait was undertaken. The first model consisted of a single leg, with anthropometrically correct mass and moment of inertia, and a point mass at the hip representing the rest of the body. A second model incorporating the physiological extension of a head-arms-trunk (HAT) segment, held upright by an actuated hip moment, was developed for comparison. Simulations were performed, using both models, and quantitatively compared with empirical gait data. There was little difference between the two models' predictions of kinematics and ground reaction force (GRF). The models agreed well with empirical data through mid-stance (20-40% of the gait cycle) suggesting that IP models adequately simulate this phase (mean error less than one standard deviation). IP models are not cyclic, however, and cannot adequately simulate double support and step-to-step transition. This is because the forces under both legs augment each other during double support to increase the vertical GRF. The incorporation of an actuated hip joint was the most novel change and added a new dimension to the classic IP model. The hip moment curve produced was similar to those measured during experimental walking trials. As a result, it was interpreted that the primary role of the hip musculature in stance is to keep the HAT upright. Careful consideration of the differences between the models throws light on what the different terms within the GRF equation truly represent. PMID:25468688

  10. SURVEY AND SUMMARY: Current methods of gene prediction, their strengths and weaknesses

    PubMed Central

    Mathé, Catherine; Sagot, Marie-France; Schiex, Thomas; Rouzé, Pierre

    2002-01-01

    While the genomes of many organisms have been sequenced over the last few years, transforming such raw sequence data into knowledge remains a hard task. A great number of prediction programs have been developed that try to address one part of this problem, which consists of locating the genes along a genome. This paper reviews the existing approaches to predicting genes in eukaryotic genomes and underlines their intrinsic advantages and limitations. The main mathematical models and computational algorithms adopted are also briefly described and the resulting software classified according to both the method and the type of evidence used. Finally, the several difficulties and pitfalls encountered by the programs are detailed, showing that improvements are needed and that new directions must be considered. PMID:12364589

  11. Institutional Assessment Tools for Sustainability in Higher Education: Strengths, Weaknesses, and Implications for Practice and Theory

    ERIC Educational Resources Information Center

    Shriberg, Michael

    2002-01-01

    This paper analyzes recent efforts to measure sustainability in higher education across institutions. The benefits of cross-institutional assessments include: identifying and benchmarking leaders and best practices; communicating common goals, experiences, and methods; and providing a directional tool to measure progress toward the concept of a…

  12. Weak rigidity in the PPN formalism

    SciTech Connect

    del Olmo, V.; Olivert, J.

    1987-04-01

    The influence of the concept of weakly rigid almost-thermodynamic material schemes on the classical deformations is analyzed. The methods of the PPN approximation are considered. In this formalism, the equations that characterize the weak rigidity are expressed. As a consequence of that, an increase of two orders of magnitude in the strain rate tensor is obtained.

  13. On modeling weak sinks in MODPATH

    USGS Publications Warehouse

    Abrams, Daniel B.; Haitjema, Henk; Kauffman, Leon J.

    2012-01-01

    Regional groundwater flow systems often contain both strong sinks and weak sinks. A strong sink extracts water from the entire aquifer depth, while a weak sink lets some water pass underneath or over the actual sink. The numerical groundwater flow model MODFLOW may allow a sink cell to act as a strong or weak sink, hence extracting all water that enters the cell or allowing some of that water to pass. A physical strong sink can be modeled by either a strong sink cell or a weak sink cell, with the latter generally occurring in low resolution models. Likewise, a physical weak sink may also be represented by either type of sink cell. The representation of weak sinks in the particle tracing code MODPATH is more equivocal than in MODFLOW. With the appropriate parameterization of MODPATH, particle traces and their associated travel times to weak sink streams can be modeled with adequate accuracy, even in single layer models. Weak sink well cells, on the other hand, require special measures as proposed in the literature to generate correct particle traces and individual travel times and hence capture zones. We found that the transit time distributions for well water generally do not require special measures provided aquifer properties are locally homogeneous and the well draws water from the entire aquifer depth, an important observation for determining the response of a well to non-point contaminant inputs.

  14. Spin Seebeck effect in a weak ferromagnet

    NASA Astrophysics Data System (ADS)

    Arboleda, Juan David; Arnache Olmos, Oscar; Aguirre, Myriam Haydee; Ramos, Rafael; Anadon, Alberto; Ibarra, Manuel Ricardo

    2016-06-01

    We report the observation of room temperature spin Seebeck effect (SSE) in a weak ferromagnetic normal spinel Zinc Ferrite (ZFO). Despite the weak ferromagnetic behavior, the measurements of the SSE in ZFO show a thermoelectric voltage response comparable with the reported values for other ferromagnetic materials. Our results suggest that SSE might possibly originate from the surface magnetization of the ZFO.

  15. Staggering towards a calculation of weak amplitudes

    SciTech Connect

    Sharpe, S.R.

    1988-09-01

    An explanation is given of the methods required to calculate hadronic matrix elements of the weak Hamiltonians using lattice QCD with staggered fermions. New results are presented for the 1-loop perturbative mixing of the weak interaction operators. New numerical techniques designed for staggered fermions are described. A preliminary result for the kaon B parameter is presented. 24 refs., 3 figs.

  16. CP Violation, Neutral Currents, and Weak Equivalence

    DOE R&D Accomplishments Database

    Fitch, V. L.

    1972-03-23

    Within the past few months two excellent summaries of the state of our knowledge of the weak interactions have been presented. Correspondingly, we will not attempt a comprehensive review but instead concentrate this discussion on the status of CP violation, the question of the neutral currents, and the weak equivalence principle.

  17. Advances in weak-values based metrology

    NASA Astrophysics Data System (ADS)

    Jordan, Andrew; Viza, Gerardo; Martínez-Rincón, Julián; Alves, Gabriel; Howell, John; Kwiat, Paul

    2015-03-01

    We theoretically and experimentally describe the relative advantages of implementing weak-values-based metrology versus standard methods. To accomplish this, we measure small optical beam deflections both a weak-values-based technique, and a standard technique. By introducing controlled external modulations of the detector, and transverse beam-jitter, we quantify the mitigation of these sources in the weak values-based experiment versus the standard experiment. In all cases, the weak-values technique performs the same or better than the standard technique by up to two orders of magnitude in precision for our parameters. We further measure the statistical efficiency of the weak-values-based technique. By post-selecting on 1% of the photons, we obtain 99% of the available Fisher information of the beam deflection parameter. We also discuss ways to recycle the discarded events, obtaining much greater precision on a measured parameter.

  18. Atomic homodyne detection of weak atomic transitions.

    PubMed

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  19. Weakly nonlinear electrophoresis of a highly charged colloidal particle

    NASA Astrophysics Data System (ADS)

    Schnitzer, Ory; Zeyde, Roman; Yavneh, Irad; Yariv, Ehud

    2013-05-01

    At large zeta potentials, surface conduction becomes appreciable in thin-double-layer electrokinetic transport. In the linear weak-field regime, where this effect is quantified by the Dukhin number, it is manifested in non-Smoluchowski electrophoretic mobilities. In this paper we go beyond linear response, employing the recently derived macroscale model of Schnitzer and Yariv ["Macroscale description of electrokinetic flows at large zeta potentials: Nonlinear surface conduction," Phys. Rev. E 86, 021503 (2012), 10.1103/PhysRevE.86.021503] as the infrastructure for a weakly nonlinear analysis of spherical-particle electrophoresis. A straightforward perturbation in the field strength is frustrated by the failure to satisfy the far-field conditions, representing a non-uniformity of the weak-field approximation at large distances away from the particle, where salt advection becomes comparable to diffusion. This is remedied using inner-outer asymptotic expansions in the spirit of Acrivos and Taylor ["Heat and mass transfer from single spheres in Stokes flow," Phys. Fluids 5, 387 (1962), 10.1063/1.1706630], with the inner region representing the particle neighborhood and the outer region corresponding to distances scaling inversely with the field magnitude. This singular scheme furnishes an asymptotic correction to the electrophoretic velocity, proportional to the applied field cubed, which embodies a host of nonlinear mechanisms unfamiliar from linear electrokinetic theories. These include the effect of induced zeta-potential inhomogeneity, animated by concentration polarization, on electro-osmosis and diffuso-osmosis; bulk advection of salt; nonuniform bulk conductivity; Coulomb body forces acting on bulk volumetric charge; and the nonzero electrostatic force exerted upon the otherwise screened particle-layer system. A numerical solution of the macroscale model validates our weakly nonlinear analysis.

  20. Weak positive cloud-to-ground flashes in Northeastern Colorado

    NASA Technical Reports Server (NTRS)

    Lopez, Raul E.; Maier, Michael W.; Garcia-Miguel, Juan A.; Holle, Ronald L.

    1991-01-01

    The frequency distributions of the peak magnetic field associated with the first detected return stroke of positive and negative cloud-to-ground (CG) flashes were studied using lightning data from northeastern Colorado. These data were obtained during 1985 with a medium-to-high gain network of three direction finders (DF's). The median signal strength of positive flashes was almost two times that of the negatives for flashes within 300 km of the DF's, which have an inherent detection-threshold bias that tends to discriminate against weak signals. This bias increases with range, and affects the detection of positive and negative flashes in different ways, because of the differing character of their distributions. Positive flashes appear to have a large percentage of signals clustered around very weak values that are lost to the medium-to-high gain Colorado Detection System very quickly with increasing range. The resulting median for positive signals could thus appear to be much larger than the median for negative signals, which are more clustered around intermediate values. When only flashes very close to the DF's are considered, however, the two distributions have almost identical medians. The large percentage of weak positive signals detected close to the DF's has not been explored previously. They have been suggested to come from intracloud discharges and thus are improperly classified as CG flashes. Evidence in hand, points to their being real positive, albeit weak CG flashes. Whether or not they are real positive ground flashes, it is important to be aware of their presence in data from magnetic DF networks.

  1. Strength calculations on airplanes

    NASA Technical Reports Server (NTRS)

    Baumann, A

    1925-01-01

    Every strength calculation, including those on airplanes, must be preceded by a determination of the forces to be taken into account. In the following discussion, it will be assumed that the magnitudes of these forces are known and that it is only a question of how, on the basis of these known forces, to meet the prescribed conditions on the one hand and the practical requirements on the other.

  2. Spectrum of Mathematical Weaknesses: Related Neuropsychological Correlates.

    PubMed

    Perna, Robert; Loughan, Ashlee R; Le, Jessica; Hertza, Jeremy; Cohen, Morris J

    2015-01-01

    Math disorders have been recognized for as long as language disorders yet have received far less research. Mathematics is a complex construct and its development may be dependent on multiple cognitive abilities. Several studies have shown that short-term memory, working memory, visuospatial skills, processing speed, and various language skills relate to and may facilitate math development and performance. The hypotheses explored in this research were that children who performed worse on math achievement than on Full-Scale IQ would exhibit weaknesses in executive functions, memory, and visuoperceptual skills. Participants included 436 children (27% girls, 73% boys; age range = 5-17 years, M(age) = 9.45 years) who were referred for neuropsychological evaluations due to academic and/or behavioral problems. This article specifically focuses on the spectrum of math weakness rather than clinical disability, which has yet to be investigated in the literature. Results suggest that children with relative weakness to impairments in math were significantly more likely to have cognitive weaknesses to impairments on neuropsychological variables, as compared with children without math weaknesses. Specifically, the math-weak children exhibit a weakness to impairment on measures involving attention, language, visuoperceptual skills, memory, reading, and spelling. Overall, our results suggest that math development is multifaceted. PMID:25117216

  3. Dynamics of Weak, Bifurcated and Strong Hydrogen Bonds in Lithium Nitrate Trihydrate

    SciTech Connect

    Werhahn, Jasper C.; Pandelov, S.; Xantheas, Sotiris S.; Iglev, H.

    2011-07-07

    The properties of three distinct types of hydrogen bonds, namely a weak, a bifurcated and a strong one, all present in/the LiNO3 (HDO)(D2O)2 hydrate lattice unit cell are studied using steady-state and time-resolved spectroscopy. The lifetimes of the OH stretching vibrations for the three individual bonds are 2.2 ps (weak), 1.7 ps (bifurcated), and 1.2 ps (strong), respectively. For the first time the properties of bifurcated H bonds can thus be unambiguously directly compared to those of weak and strong H bonds in the same system. The values of their OH stretching vibration lifetime, anharmonicity, red shift and bond strength lie between those for the strong and weak H bonds. The experimentally observed inhomogeneous broadening of their spectral signature is attributed to the coupling with a low frequency intermolecular wagging vibration/

  4. Abdominal muscle and quadriceps strength in chronic obstructive pulmonary disease

    PubMed Central

    Man, W; Hopkinson, N; Harraf, F; Nikoletou, D; Polkey, M; Moxham, J

    2005-01-01

    Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls. Methods: Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables. Results: Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI –17.9 to –4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H2O v 204.8 cm H2O; 95% CI –5.4 to 50.6; p = 0.11). Conclusions: Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes. PMID:15923239

  5. Structural features of sequential weak measurements

    NASA Astrophysics Data System (ADS)

    Diósi, Lajos

    2016-07-01

    We discuss the abstract structure of sequential weak measurement (WM) of general observables. In all orders, the sequential WM correlations without postselection yield the corresponding correlations of the Wigner function, offering direct quantum tomography through the moments of the canonical variables. Correlations in spin-1/2 sequential weak measurements coincide with those in strong measurements, they are constrained kinematically, and they are equivalent with single measurements. In sequential WMs with postselection, an anomaly occurs, different from the weak value anomaly of single WMs. In particular, the spread of polarization σ ̂ as measured in double WMs of σ ̂ will diverge for certain orthogonal pre- and postselected states.

  6. Complex weak values in quantum measurement

    SciTech Connect

    Jozsa, Richard

    2007-10-15

    In the weak value formalism of Aharonov et al., the weak value A{sub w} of any observable A is generally a complex number. We derive a physical interpretation of its value in terms of the shift in the measurement pointer's mean position and mean momentum. In particular, we show that the mean position shift contains a term jointly proportional to the imaginary part of the weak value and the rate at which the pointer is spreading in space as it enters the measurement interaction.

  7. Weak side of strong topological insulators

    NASA Astrophysics Data System (ADS)

    Sbierski, Björn; Schneider, Martin; Brouwer, Piet W.

    2016-04-01

    Strong topological insulators may have nonzero weak indices. The nonzero weak indices allow for the existence of topologically protected helical states along line defects of the lattice. If the lattice admits line defects that connect opposite surfaces of a slab of such a "weak-and-strong" topological insulator, these states effectively connect the surface states at opposite surfaces. Depending on the phases accumulated along the dislocation lines, this connection results in a suppression of in-plane transport and the opening of a spectral gap or in an enhanced density of states and an increased conductivity.

  8. What controls the strength and brittleness of shale rocks?

    NASA Astrophysics Data System (ADS)

    Rybacki, Erik; Reinicke, Andreas; Meier, Tobias; Makasi, Masline; Dresen, Georg

    2014-05-01

    With respect to the productivity of gas shales, in petroleum science the mechanical behavior of shales is often classified into rock types of high and low 'brittleness', sometimes also referred to as 'fraccability'. The term brittleness is not well defined and different definitions exist, associated with elastic properties (Poisson's ratio, Young's modulus), with strength parameters (compressive and tensile strength), frictional properties (cohesion, friction coefficient), hardness (indentation), or with the strain or energy budget (ratio of reversible to the total strain or energy, respectively). Shales containing a high amount of clay and organic matter are usually considered as less brittle. Similarly, the strength of shales is usually assumed to be low if they contain a high fraction of weak phases. We performed mechanical tests on a series of shales with different mineralogical compositions, varying porosity, and low to high maturity. Using cylindrical samples, we determined the uniaxial and triaxial compressive strength, static Young's modulus, the tensile strength, and Mode I fracture toughness. The results show that in general the uniaxial compressive strength (UCS) linearly increases with increasing Young's modulus (E) and both parameters increase with decreasing porosity. However, the strength and elastic modulus is not uniquely correlated with the mineral content. For shales with a relatively low quartz and high carbonate content, UCS and E increase with increasing quartz content, whereas for shales with a relatively low amount for carbonates, but high quartz content, both parameters increase with decreasing fraction of the weak phases (clays, kerogen). In contrast, the average tensile strength of all shale-types appears to increase with increasing quartz fraction. The internal friction coefficient of all investigated shales decreases with increasing pressure and may approach rather high values (up to ≡ 1). Therefore, the mechanical strength and

  9. Competition between weak localization and ballistic transport.

    PubMed

    Tian, Chushun

    2009-06-19

    High-frequency transport in perfect periodic dielectric cylinder arrays is studied. We analytically calculate the diffusive-ballistic transport crossover, which displays the competition between weak localization and ballistic transport. PMID:19659008

  10. Sodium in weak G-band giants

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy J.; Lambert, David L.

    1994-01-01

    Sodium abundances have been determined for eight weak G-band giants whose atmospheres are greatly enriched with products of the CN-cycling H-burning reactions. Systematic errors are minimized by comparing the weak G-band giants to a sample of similar but normal giants. If, further, Ca is selected as a reference element, model atmosphere-related errors should largely be removed. For the weak-G-band stars (Na/Ca) = 0.16 +/- 0.01, which is just possibly greater than the result (Na/Ca) = 0.10 /- 0.03 from the normal giants. This result demonstrates that the atmospheres of the weak G-band giants are not seriously contaminated with products of ON cycling.

  11. Parametric instabilities in weakly magnetized plasma

    SciTech Connect

    Weatherall, J.C.; Goldman, M.V.; Nicholson, D.R.

    1981-05-15

    Parametric instabilities in a weakly magnetized plasma are discussed. The results are applied to waves excited by electron streams which travel outward from the Sun along solar-wind magnetic field lines, as in a type III solar radio burst.

  12. Sensor/amplifier for weak light sources

    NASA Technical Reports Server (NTRS)

    Desmet, D. J.; Jason, A. J.; Parr, A. C.

    1980-01-01

    Light sensor/amplifier circuit detects weak light converts it into strong electrical signal in electrically noisy environment. Circuit is relatively simple and uses inexpensive, readily available components. Device is useful in such applications as fire detection and photographic processing.

  13. Experimental studies of weakly coupled superconductors (Review)

    NASA Astrophysics Data System (ADS)

    Dmitrenko, I. M.

    2004-07-01

    A review is given of the main experimental results obtained in research on weakly coupled superconductors after 1964 at the Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkov (ILTPE).

  14. Experimental and numerical investigations of beryllium strength models using the Rayleigh-Taylor instability

    NASA Astrophysics Data System (ADS)

    Henry de Frahan, M. T.; Belof, J. L.; Cavallo, R. M.; Raevsky, V. A.; Ignatova, O. N.; Lebedev, A.; Ancheta, D. S.; El-dasher, B. S.; Florando, J. N.; Gallegos, G. F.; Johnsen, E.; LeBlanc, M. M.

    2015-06-01

    We present a set of high explosive driven Rayleigh-Taylor strength experiments for beryllium to produce data to distinguish predictions by various strength models. Design simulations using existing strength model parameterizations from Steinberg-Lund and Preston-Tonks-Wallace (PTW) suggested an optimal design that would delineate between not just different strength models, but different parameters sets of the PTW model. Application of the models to the post-shot results, however, suggests growth consistent with little material strength. We focus mostly on efforts to simulate the data using published strength models as well as the more recent RING relaxation model developed at VNIIEF. The results of the strength experiments indicate weak influence of strength in mitigating the growth with the RING model coming closest to predicting the material behavior. Finally, we present shock and ramp-loading recovery experiments.

  15. Experimental and numerical investigations of beryllium strength models using the Rayleigh-Taylor instability

    SciTech Connect

    Henry de Frahan, M. T. Johnsen, E.; Belof, J. L.; Cavallo, R. M.; Ancheta, D. S.; El-dasher, B. S.; Florando, J. N.; Gallegos, G. F.; LeBlanc, M. M.; Raevsky, V. A.; Ignatova, O. N.; Lebedev, A.

    2015-06-14

    We present a set of high explosive driven Rayleigh-Taylor strength experiments for beryllium to produce data to distinguish predictions by various strength models. Design simulations using existing strength model parameterizations from Steinberg-Lund and Preston-Tonks-Wallace (PTW) suggested an optimal design that would delineate between not just different strength models, but different parameters sets of the PTW model. Application of the models to the post-shot results, however, suggests growth consistent with little material strength. We focus mostly on efforts to simulate the data using published strength models as well as the more recent RING relaxation model developed at VNIIEF. The results of the strength experiments indicate weak influence of strength in mitigating the growth with the RING model coming closest to predicting the material behavior. Finally, we present shock and ramp-loading recovery experiments.

  16. Thigh Muscle Strength in Senior Athletes and Healthy Controls

    PubMed Central

    McCrory, Jean L; Salacinski, Amanda J; Hunt, Sarah E; Greenspan, Susan L

    2016-01-01

    Exercise is commonly recommended to counteract aging-related muscle weakness. While numerous exercise intervention studies on the elderly have been performed, few have included elite senior athletes, such as those who participate in the National Senior Games. The extent to which participation in highly competitive exercise affects muscle strength is unknown, as well as the extent to which such participation mitigates any aging-related strength losses. The purpose of this study was to examine isometric thigh muscle strength in selected athletes of the National Senior Games and healthy noncompetitive controls of similar age, as well as to investigate strength changes with aging in both groups. In all, 95 athletes of the Games and 72 healthy controls participated. Of the senior athletes, 43 were runners, 12 cyclists, and 40 swimmers. Three trials of isometric knee flexion and extension strength were collected using a load cell affixed to a custom-designed chair. Strength data were normalized to dual-energy x-ray absorptiometry-obtained lean mass of the leg. A 3-factor multivariate analysis of variance (group × gender × age group) was performed, which included both the extension and flexion variables ([alpha] = 0.05). Athletes exhibited 38% more extension strength and 66% more flexion strength than the controls (p < 0.001). Strength did not decrease with advancing age in either the athletes or the controls (p = 0.345). In conclusion, senior athletes who participate in highly competitive exercise have greater strength than healthy aged-matched individuals who do not. Neither group displayed the expected strength losses with aging. Our subject cohorts, however, were not typical of those over age 65 years because individuals with existing health conditions were excluded from the study. PMID:19972628

  17. Some Topics in Weak and Electromagnetic Interactions

    NASA Astrophysics Data System (ADS)

    Bjorken, James D.

    1982-01-01

    The following sections are included: * INTRODUCTION * LECTURE I QUANTUM-ELECTRODYNAMICS TESTS; TESTS OF Jμ Jμ STRUCTURE IN WEAK INTERACTIONS; HIGHER-ORDER WEAK INTERACTIONS * LECTURE II PHENOMENOLOGY OF DEEP-INELASTIC PROCESSES; NO FINAL-STATE HADRONS OBSERVED * LECTURE III LIGHT-CONE COMMUTATORS; MODELS OF THE STRUCTURE FUNCTIONS * LECTURE IV HADRON FINAL STATES IN DEEP-INELASTIC PROCESSES; GENERAL CONSIDERATIONS * LECTURE V INCLUSIVE PROCESSES AT VERY HIGH TRANSVERSE MOMENTUM * REFERENCES

  18. Deterministic implementation of weak quantum cubic nonlinearity

    SciTech Connect

    Marek, Petr; Filip, Radim; Furusawa, Akira

    2011-11-15

    We propose a deterministic implementation of weak cubic nonlinearity, which is a basic building block of a full-scale continuous-variable quantum computation. Our proposal relies on preparation of a specific ancillary state and transferring its nonlinear properties onto the desired target by means of deterministic Gaussian operations and feed forward. We show that, despite the imperfections arising from the deterministic nature of the operation, the weak quantum nonlinearity can be implemented and verified with the current level of technology.

  19. Looking for heavier weak bosons with DUMAND

    NASA Technical Reports Server (NTRS)

    Brown, R. W.; Stecker, F. W.

    1980-01-01

    One or more heavier weak bosons may coexist with the standard weak boson, a broad program may be laid out for a search for the heavier W's via change in the total cross section due to the additional propagator, a concomitant search, and a subsequent search for significant antimatter in the universe involving the same annihilation, but being independent of possible neutrino oscillations. The program is likely to require detectors sensitive to higher energies, such as acoustic detectors.

  20. Electromagnetic and Weak transitions in light nuclei

    SciTech Connect

    M. Viviani; L.E. Marcucci; A. Kievsky; S. Rosati; R. Schiavilla

    2002-09-01

    Recent advances in the study of the p -- d radiative and mu -- {sup 3}He weak capture processes by our group are presented and discussed. The trinucleon bound and scattering states have been obtained from variational calculations by expanding the corresponding wave functions in terms of correlated hyper-spherical harmonic functions. The electromagnetic and weak transition currents include one- and two-body operators. The accuracy achieved in these calculations allows for interesting comparisons with experimental data.

  1. Atypical presentation of GNE myopathy with asymmetric hand weakness.

    PubMed

    de Dios, John Karl L; Shrader, Joseph A; Joe, Galen O; McClean, Jeffrey C; Williams, Kayla; Evers, Robert; Malicdan, May Christine V; Ciccone, Carla; Mankodi, Ami; Huizing, Marjan; McKew, John C; Bluemke, David A; Gahl, William A; Carrillo-Carrasco, Nuria

    2014-12-01

    GNE myopathy is a rare autosomal recessive muscle disease caused by mutations in GNE, the gene encoding the rate-limiting enzyme in sialic acid biosynthesis. GNE myopathy usually manifests in early adulthood with distal myopathy that progresses slowly and symmetrically, first involving distal muscles of the lower extremities, followed by proximal muscles with relative sparing of the quadriceps. Upper extremities are typically affected later in the disease. We report a patient with GNE myopathy who presented with asymmetric hand weakness. He had considerably decreased left grip strength, atrophy of the left anterior forearm and fibro-fatty tissue replacement of left forearm flexor muscles on T1-weighted magnetic resonance imaging. The patient was an endoscopist and thus the asymmetric hand involvement may be associated with left hand overuse in daily repetitive pinching and gripping movements, highlighting the possible impact of environmental factors on the progression of genetic muscle conditions. PMID:25182749

  2. Atypical presentation of GNE myopathy with asymmetric hand weakness.

    PubMed

    de Dios, John Karl L; Shrader, Joseph A; Joe, Galen O; McClean, Jeffrey C; Williams, Kayla; Evers, Robert; Malicdan, May Christine V; Ciccone, Carla; Mankodi, Ami; Huizing, Marjan; McKew, John C; Bluemke, David A; Gahl, William A; Carrillo-Carrasco, Nuria

    2014-12-01

    GNE myopathy is a rare autosomal recessive muscle disease caused by mutations in GNE, the gene encoding the rate-limiting enzyme in sialic acid biosynthesis. GNE myopathy usually manifests in early adulthood with distal myopathy that progresses slowly and symmetrically, first involving distal muscles of the lower extremities, followed by proximal muscles with relative sparing of the quadriceps. Upper extremities are typically affected later in the disease. We report a patient with GNE myopathy who presented with asymmetric hand weakness. He had considerably decreased left grip strength, atrophy of the left anterior forearm and fibro-fatty tissue replacement of left forearm flexor muscles on T1-weighted magnetic resonance imaging. The patient was an endoscopist and thus the asymmetric hand involvement may be associated with left hand overuse in daily repetitive pinching and gripping movements, highlighting the possible impact of environmental factors on the progression of genetic muscle conditions.

  3. Beyond strong and weak: rethinking postdictatorship civil societies.

    PubMed

    Riley, Dylan; Fernández, Juan J

    2014-09-01

    What is the impact of dictatorships on postdictatorial civil societies? Bottom-up theories suggest that totalitarian dictatorships destroy civil society while authoritarian ones allow for its development. Top-down theories of civil society suggest that totalitarianism can create civil societies while authoritarianism is unlikely to. This article argues that both these perspectives suffer from a one-dimensional understanding of civil society that conflates strength and autonomy. Accordingly we distinguish these two dimensions and argue that totalitarian dictatorships tend to create organizationally strong but heteronomous civil societies, while authoritarian ones tend to create relatively autonomous but organizationally weak civil societies. We then test this conceptualization by closely examining the historical connection between dictatorship and civil society development in Italy (a posttotalitarian case) and Spain (a postauthoritarian one). Our article concludes by reflecting on the implications of our argument for democratic theory, civil society theory, and theories of regime variation. PMID:25811069

  4. Magnetophoresis of diamagnetic microparticles in a weak magnetic field.

    PubMed

    Zhu, Gui-Ping; Hejiazan, Majid; Huang, Xiaoyang; Nguyen, Nam-Trung

    2014-12-21

    Magnetic manipulation is a promising technique for lab-on-a-chip platforms. The magnetic approach can avoid problems associated with heat, surface charge, ionic concentration and pH level. The present paper investigates the migration of diamagnetic particles in a ferrofluid core stream that is sandwiched between two diamagnetic streams in a uniform magnetic field. The three-layer flow is expanded in a circular chamber for characterisation based on imaging of magnetic nanoparticles and fluorescent microparticles. A custom-made electromagnet generates a uniform magnetic field across the chamber. In a relatively weak uniform magnetic field, the diamagnetic particles in the ferrofluid move and spread across the chamber. Due to the magnetization gradient formed by the ferrofluid, diamagnetic particles undergo negative magnetophoresis and move towards the diamagnetic streams. The effects of magnetic field strength and the concentration of diamagnetic particles are studied in detail. PMID:25325774

  5. Beyond strong and weak: rethinking postdictatorship civil societies.

    PubMed

    Riley, Dylan; Fernández, Juan J

    2014-09-01

    What is the impact of dictatorships on postdictatorial civil societies? Bottom-up theories suggest that totalitarian dictatorships destroy civil society while authoritarian ones allow for its development. Top-down theories of civil society suggest that totalitarianism can create civil societies while authoritarianism is unlikely to. This article argues that both these perspectives suffer from a one-dimensional understanding of civil society that conflates strength and autonomy. Accordingly we distinguish these two dimensions and argue that totalitarian dictatorships tend to create organizationally strong but heteronomous civil societies, while authoritarian ones tend to create relatively autonomous but organizationally weak civil societies. We then test this conceptualization by closely examining the historical connection between dictatorship and civil society development in Italy (a posttotalitarian case) and Spain (a postauthoritarian one). Our article concludes by reflecting on the implications of our argument for democratic theory, civil society theory, and theories of regime variation.

  6. Dynamic Strength of Materials

    NASA Astrophysics Data System (ADS)

    Chhabildas, Lalit

    2011-06-01

    Historically when shock loading techniques became accessible in the early fifties it was assumed that materials behave like fluids implying that materials cannot support any shear stresses. Early and careful investigation in the sixties by G. R. Fowles in aluminum indicated otherwise. When he compared his Hugoniot compression measurements to hydrostatic pressure compression measurements in the pressure volume plane he noticed that the shock data lay above the hydrostatic compression curve - which laid the ground work for what is the basis for elastic-plastic theories that exist today. In this talk, a brief historical perspective on strength measurements in materials will be discussed including how time-resolved techniques have played a role in allowing estimates of the strength of materials at over Mbar stress. This is crucial especially at high stresses since we are determining values that are small compared to the loading stress. Even though we have made considerable progress in our understanding of materials, there are still many anomalies and unanswered questions. Some of these anomalies are fertile grounds for further and future research and will be mentioned.

  7. Effect of Gender, Disease Duration and Treatment on Muscle Strength in Myasthenia Gravis

    PubMed Central

    Citirak, Gülsenay; Cejvanovic, Sanja; Andersen, Henning; Vissing, John

    2016-01-01

    Introduction The aim of this observational, cross-sectional study was to quantify the potential presence of muscle weakness among patients with generalized myasthenia gravis (gMG). The influence of gender, treatment intensity and disease duration on muscle strength and disease progression was also assessed. Methods Muscle strength was tested in 8 muscle groups by manual muscle testing and by hand-held dynamometry in 107 patients with gMG and 89 healthy age- and gender-matched controls. Disease duration, severity and treatment history were reviewed and compared with muscle strength. Results Patients had reduced strength in all tested muscle group compared to control subjects (p<0.05). Women with gMG were stronger than men (decrease in strength 22.6% vs. 32.7% in men, P<0.05). Regional differences in muscle weakness were also evident, with proximal muscles being more affected. Interestingly, muscle strength did not correlate with disease duration and treatment intensity. Conclusions The results of this study show that in patients with gMG; 1) there is significant muscle weakness, 2) muscle weakness is more pronounced in men than women, 3) shoulder abductors, hip flexors, and neck muscles are the most affected muscle groups and 4) disease duration or treatment intensity alone are not predictors of loss of muscle strength in gMG. PMID:27741232

  8. Oscillator strengths and collision strengths for S III

    NASA Technical Reports Server (NTRS)

    Ho, Y. K.; Henry, R. J. W.

    1984-01-01

    The present calculation, in a close-coupled approximation for the energy range up to 1,000,000 K, yields collision strengths for the electron impact excitation of S III from the ground 3p2 3P state to the excited states 3s3p3 3D0, 3P0, 3S0, 3d 3D0, 3P0, and 4s 3P0. Also obtained are those transitions' oscillator strengths, and strengths for others involving 3p2 1D and 1S. Configuration-interaction target wave functions yielding oscillator strengths that are accurate to 20 percent are used in collision strength calculations.

  9. Strength Training and Children's Health.

    ERIC Educational Resources Information Center

    Faigenbaum, Avery D.

    2001-01-01

    Provides an overview of the potential health benefits of strength training for children, discussing the role of strength training in preventing sports-related injuries and highlighting design considerations for such programs. The focus is on musculoskeletal adaptations to strength training that are observable in healthy children. Guidelines for…

  10. Strength Development for Young Adolescents

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; Jackson, Allen; Gaudet, Laura

    2009-01-01

    Participation in strength training is important for older children or young adolescences who wish to improve fitness or participate in sports. When designing strength training programs for our youth this age group is immature anatomically, physiologically, and psychologically. For the younger or inexperienced group the strength training activities…

  11. The fracture strength and frictional strength of Weber Sandstone

    USGS Publications Warehouse

    Byerlee, J.D.

    1975-01-01

    The fracture strength and frictional strength of Weber Sandstone have been measured as a function of confining pressure and pore pressure. Both the fracture strength and the frictional strength obey the law of effective stress, that is, the strength is determined not by the confining pressure alone but by the difference between the confining pressure and the pore pressure. The fracture strength of the rock varies by as much as 20 per cent depending on the cement between the grains, but the frictional strength is independent of lithology. Over the range 0 2 kb, ??=0??5 + 0??6??n. This relationship also holds for other rocks such as gabbro, dunite, serpentinite, granite and limestone. ?? 1975.

  12. Improving the payoffs of cooperators in three-player cooperative game using weak measurements

    NASA Astrophysics Data System (ADS)

    Liao, Xiang-Ping; Ding, Xiang-Zhuo; Fang, Mao-Fa

    2015-12-01

    In this paper, an efficient method is proposed to improve the payoffs of cooperators in cooperative three-player quantum game under the action of amplitude damping, bit flip and depolarizing channels using weak measurements. It is shown that the payoffs of cooperators can be enhanced to a great extent in the case of amplitude damping channel, and the payoff sudden death can be avoided in the case of bit flip and depolarizing channels. Moreover, the payoffs of cooperators tend to a constant by changing weak measurement strength in spite of sufficiently strong decoherence.

  13. Using weak nonlinearity under decoherence for macroscopic entanglement generation and quantum computation

    SciTech Connect

    Jeong, Hyunseok

    2005-09-15

    Recently, there have been several suggestions that weak Kerr nonlinearity can be used for generation of macroscopic superpositions and entanglement and for linear optics quantum computation. However, it is not immediately clear that this approach can overcome decoherence effects. Our numerical study shows that nonlinearity of weak strength could be useful for macroscopic entanglement generation and quantum gate operations in the presence of decoherence. We suggest specific values for real experiments based on our analysis. Our discussion shows that the generation of macroscopic entanglement using this approach is within the reach of current technology.

  14. Measurement of a weak transition moment using Coherent Control

    NASA Astrophysics Data System (ADS)

    Antypas, Dionysios

    We have developed a two-pathway Coherent Control technique for measurements of weak optical transition moments. We demonstrate this technique through a measurement of the transition moment of the highly-forbidden magnetic dipole transition between the 6s2S 1/21/2 and 7s2S 1/21/2 states in atomic Cesium. The experimental principle is based on a two-pathway excitation, using two phase-coherent laser fields, a fundamental field at 1079 nm and its second harmonic at 539.5 nm. The IR field induces a strong two-photon transition, while the 539.5 nm field drives a pair of weak one-photon transitions: a Stark-induced transition of controllable strength as well as the magnetic dipole transition. Observations of the interference between these transitions for different Stark-induced transition amplitudes, allow a measurement of the ratio of the magnetic dipole to the Stark-induced moment. The interference between the transitions is controlled by modulation of the phase-delay between the two optical fields. Our determination of the magnetic dipole moment is at the 0.4% level and in good agreement with previous measurements, and serves as a benchmark for our technique and apparatus. We anticipate that with further improvement of the apparatus detection sensitivity, the demonstrated scheme can be used for measurements of the very weak Parity Violation transition moment on the Cesium 6s2 S1/2→7s2 S1/2 transition.

  15. Failure strength of icy lithospheres

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Banerdt, W. B.

    1987-01-01

    Lithospheric strengths derived from friction on pre-existing fractures and ductile flow laws show that the tensile strength of intact ice under applicable conditions is actually an order of magnitude stronger than widely assumed. It is demonstrated that this strength is everywhere greater than that required to initiate frictional sliding on pre-existing fractures and faults. Because the tensile strength of intact ice increases markedly with confining pressure, it actually exceeds the frictional strength at all depths. Thus, icy lithospheres will fail by frictional slip along pre-existing fractures at yeild stresses greater than previously assumed rather than opening tensile cracks in intact ice.

  16. High Strength Development at Incompatible Semicrystalline Polymer-Polymer Interfaces

    NASA Astrophysics Data System (ADS)

    Hong, C. H.; Wool, Richard

    2007-03-01

    For incompatible A/B interfaces, the strength G1c is related to the equilibrium width w (normalized to the tube diameter) of the interface by G1c/G* = (w-1), where G* is the virgin strength [R.P. Wool, C.R, Chimie, 9 (2006) 25]. However, the interface strength is quite weak due to very limited interdiffusion. The mechanism of high strength development of a series of thermoplastic polyurethane elastomers (TPU) bonding with ethylene vinyl alcohol copolymers (EVOH) was investigated. During cool down of the A/B interface in the co-extruded melt, there exits a unique process window---the α-β window-which promotes considerable strength development. We used the differences in melting points and the volume contraction during asymmetric crystallization to generate influxes (σ nano-nails/unit area), where an influx occurs by the fluid being pulled into the crystallizing side. TPU samples with higher degree of crystallization typically exhibited higher peel strengths, due to the formation of both inter- and intra- spherulitic influxes of nano-dimension across the interface. The peel energy now behaves as G1c˜ σL^2, where L is the length of the influx and L>>w. Annealing between the α and βt relaxation temperatures of the EVOH generated additional influxes which provided significant connectivity and peel strength.

  17. Gaussian discriminating strength

    NASA Astrophysics Data System (ADS)

    Rigovacca, L.; Farace, A.; De Pasquale, A.; Giovannetti, V.

    2015-10-01

    We present a quantifier of nonclassical correlations for bipartite, multimode Gaussian states. It is derived from the Discriminating Strength measure, introduced for finite dimensional systems in Farace et al., [New J. Phys. 16, 073010 (2014), 10.1088/1367-2630/16/7/073010]. As the latter the new measure exploits the quantum Chernoff bound to gauge the susceptibility of the composite system with respect to local perturbations induced by unitary gates extracted from a suitable set of allowed transformations (the latter being identified by posing some general requirements). Closed expressions are provided for the case of two-mode Gaussian states obtained by squeezing or by linearly mixing via a beam splitter a factorized two-mode thermal state. For these density matrices, we study how nonclassical correlations are related with the entanglement present in the system and with its total photon number.

  18. High strength ferritic alloy

    DOEpatents

    Hagel, William C.; Smidt, Frederick A.; Korenko, Michael K.

    1977-01-01

    A high-strength ferritic alloy useful for fast reactor duct and cladding applications where an iron base contains from about 9% to about 13% by weight chromium, from about 4% to about 8% by weight molybdenum, from about 0.2% to about 0.8% by weight niobium, from about 0.1% to about 0.3% by weight vanadium, from about 0.2% to about 0.8% by weight silicon, from about 0.2% to about 0.8% by weight manganese, a maximum of about 0.05% by weight nitrogen, a maximum of about 0.02% by weight sulfur, a maximum of about 0.02% by weight phosphorous, and from about 0.04% to about 0.12% by weight carbon.

  19. Hadronic Weak Interaction Studies at the SNS

    NASA Astrophysics Data System (ADS)

    Fomin, Nadia

    2016-03-01

    Neutrons have been a useful probe in many fields of science, as well as an important physical system for study in themselves. Modern neutron sources provide extraordinary opportunities to study a wide variety of physics topics. Among them is a detailed study of the weak interaction. An overview of studies of the hadronic weak (quark-quark) as well as semi-leptonic (quark-lepton) interactions at the Spallation Neutron Source (SNS) is presented. These measurements, done in few-nucleon systems, are finally letting us gain knowledge of the hadronic weak interaction without the contributions from nuclear effects. Forthcoming results from the NPDGamma experiment will, due to the simplicity of the neutron, provide an unambiguous measurement of the long range pion-nucleon weak coupling (often referred to as hπ), which will finally test the theoretical predictions. Results from NPDGamma and future results from the n +3 He experiment will need to be complemented by additional measurements to completely describe the hadronic weak interaction.

  20. Explaining numeracy development in weak performing kindergartners.

    PubMed

    Toll, Sylke W M; Van Luit, Johannes E H

    2014-08-01

    Gaining better insight into precursors of early numeracy in young children is important, especially in those with inadequate numeracy skills. Therefore, in the current study, visual and verbal working memory, non-symbolic and symbolic comparison skills, and specific math-related language were used to explain early numeracy performance and development of weak performing children throughout kindergarten. The early numeracy ability of both weak performers and typical performers was measured at four time points during 2 years of kindergarten to compare growth rates. Results show a significant faster development of early numeracy in the weak performers. The development of weak performers' numeracy was influenced by verbal working memory, symbolic comparison skills, and math language, whereas only math language was positively related to the slope of typical performers' numeracy. In the weak performers, visual working memory, non-symbolic comparison skills, and math language showed an effect on the initial early numeracy level of these children. The intercept of the typical performers was predicted by five covariates, all except non-symbolic comparison. PMID:24786672

  1. DRAM Weak Cell Characterization for Retention Time.

    PubMed

    Kang, Jonghyuk; Lee, Sungho; Choi, Byoungdeog

    2016-05-01

    This work proposes a sequence of tests for detecting refresh weak cells based on data retention time distribution in the main cell array of DRAMs and verify the feasibility of the proposed method through analysis of 30 nm design-rule DRAM cells with Recess Channel Array Transistor (RCAT) and Buried Channel Array Transistor (BCAT). Basic idea of the proposed mechanism is to test with different bias conditions and break down retention failures based on their root causes such as Gate Induced Drain Leakage, sub-threshold leakage and junction leakage. This categorization helps to determine the physical locations of each failure group, enabling precise Physical Failure Analysis (PFA). The characterization of data retention weak cells for 30 nm design rule DRAMs with BCAT and RCAT has been investigated. Most weak cells were classified as GIDL leaky cells in both cases. In the case of BCAT, the distance between the word line and the storage node, caused by the process distribution, is the main origin of weak cells. In the case of RCAT, the sharp corner of the active layer in the storage node is the main cause of weak cells. PMID:27483878

  2. Faithful conditional quantum state transfer between weakly coupled qubits

    NASA Astrophysics Data System (ADS)

    Miková, M.; Straka, I.; Mičuda, M.; Krčmarský, V.; Dušek, M.; Ježek, M.; Fiurášek, J.; Filip, R.

    2016-08-01

    One of the strengths of quantum information theory is that it can treat quantum states without referring to their particular physical representation. In principle, quantum states can be therefore fully swapped between various quantum systems by their mutual interaction and this quantum state transfer is crucial for many quantum communication and information processing tasks. In practice, however, the achievable interaction time and strength are often limited by decoherence. Here we propose and experimentally demonstrate a procedure for faithful quantum state transfer between two weakly interacting qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer of an arbitrary unknown state of a source qubit onto a target qubit prepared initially in a known state. The transfer is achieved by a combination of a suitable measurement of the source qubit and quantum filtering on the target qubit depending on the outcome of measurement on the source qubit. We experimentally verify feasibility and robustness of the transfer using a linear optical setup with qubits encoded into polarization states of single photons.

  3. Faithful conditional quantum state transfer between weakly coupled qubits.

    PubMed

    Miková, M; Straka, I; Mičuda, M; Krčmarský, V; Dušek, M; Ježek, M; Fiurášek, J; Filip, R

    2016-01-01

    One of the strengths of quantum information theory is that it can treat quantum states without referring to their particular physical representation. In principle, quantum states can be therefore fully swapped between various quantum systems by their mutual interaction and this quantum state transfer is crucial for many quantum communication and information processing tasks. In practice, however, the achievable interaction time and strength are often limited by decoherence. Here we propose and experimentally demonstrate a procedure for faithful quantum state transfer between two weakly interacting qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer of an arbitrary unknown state of a source qubit onto a target qubit prepared initially in a known state. The transfer is achieved by a combination of a suitable measurement of the source qubit and quantum filtering on the target qubit depending on the outcome of measurement on the source qubit. We experimentally verify feasibility and robustness of the transfer using a linear optical setup with qubits encoded into polarization states of single photons. PMID:27562544

  4. Faithful conditional quantum state transfer between weakly coupled qubits

    PubMed Central

    Miková, M.; Straka, I.; Mičuda, M.; Krčmarský, V.; Dušek, M.; Ježek, M.; Fiurášek, J.; Filip, R.

    2016-01-01

    One of the strengths of quantum information theory is that it can treat quantum states without referring to their particular physical representation. In principle, quantum states can be therefore fully swapped between various quantum systems by their mutual interaction and this quantum state transfer is crucial for many quantum communication and information processing tasks. In practice, however, the achievable interaction time and strength are often limited by decoherence. Here we propose and experimentally demonstrate a procedure for faithful quantum state transfer between two weakly interacting qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer of an arbitrary unknown state of a source qubit onto a target qubit prepared initially in a known state. The transfer is achieved by a combination of a suitable measurement of the source qubit and quantum filtering on the target qubit depending on the outcome of measurement on the source qubit. We experimentally verify feasibility and robustness of the transfer using a linear optical setup with qubits encoded into polarization states of single photons. PMID:27562544

  5. Faithful conditional quantum state transfer between weakly coupled qubits.

    PubMed

    Miková, M; Straka, I; Mičuda, M; Krčmarský, V; Dušek, M; Ježek, M; Fiurášek, J; Filip, R

    2016-08-26

    One of the strengths of quantum information theory is that it can treat quantum states without referring to their particular physical representation. In principle, quantum states can be therefore fully swapped between various quantum systems by their mutual interaction and this quantum state transfer is crucial for many quantum communication and information processing tasks. In practice, however, the achievable interaction time and strength are often limited by decoherence. Here we propose and experimentally demonstrate a procedure for faithful quantum state transfer between two weakly interacting qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer of an arbitrary unknown state of a source qubit onto a target qubit prepared initially in a known state. The transfer is achieved by a combination of a suitable measurement of the source qubit and quantum filtering on the target qubit depending on the outcome of measurement on the source qubit. We experimentally verify feasibility and robustness of the transfer using a linear optical setup with qubits encoded into polarization states of single photons.

  6. Bats respond to very weak magnetic fields.

    PubMed

    Tian, Lan-Xiang; Pan, Yong-Xin; Metzner, Walter; Zhang, Jin-Shuo; Zhang, Bing-Fang

    2015-01-01

    How animals, including mammals, can respond to and utilize the direction and intensity of the Earth's magnetic field for orientation and navigation is contentious. In this study, we experimentally tested whether the Chinese Noctule, Nyctalus plancyi (Vespertilionidae) can sense magnetic field strengths that were even lower than those of the present-day geomagnetic field. Such field strengths occurred during geomagnetic excursions or polarity reversals and thus may have played an important role in the evolution of a magnetic sense. We found that in a present-day local geomagnetic field, the bats showed a clear preference for positioning themselves at the magnetic north. As the field intensity decreased to only 1/5th of the natural intensity (i.e., 10 μT; the lowest field strength tested here), the bats still responded by positioning themselves at the magnetic north. When the field polarity was artificially reversed, the bats still preferred the new magnetic north, even at the lowest field strength tested (10 μT), despite the fact that the artificial field orientation was opposite to the natural geomagnetic field (P<0.05). Hence, N. plancyi is able to detect the direction of a magnetic field even at 1/5th of the present-day field strength. This high sensitivity to magnetic fields may explain how magnetic orientation could have evolved in bats even as the Earth's magnetic field strength varied and the polarity reversed tens of times over the past fifty million years.

  7. Weak lensing in the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Troxel, Michael

    2016-03-01

    I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.

  8. Composition of weakly altered Martian crust

    NASA Technical Reports Server (NTRS)

    Mustard, J. F.; Murchie, S. L.; Erard, S.

    1993-01-01

    The mineralogic and chemical composition of weakly altered crust remains an unresolved question for Mars. Dark regions hold clues to the composition since they are thought to comprise surface exposures of weakly altered crustal materials. Understanding the in situ composition of relatively pristine crustal rocks in greater detail is important for investigating basic volcanic processes. Also, this will provide additional constraints on the chemical pathways by which pristine rocks are altered to produce the observed ferric iron-bearing assemblages and inferred clay silicate, sulphate, and magnetic oxide phases. Reflectance spectra of dark regions obtained with the ISM instrument are being used to determine the basic mineralogy of weakly altered crust for a variety of regions on Mars.

  9. Weak self-adjoint differential equations

    NASA Astrophysics Data System (ADS)

    Gandarias, M. L.

    2011-07-01

    The concepts of self-adjoint and quasi self-adjoint equations were introduced by Ibragimov (2006 J. Math. Anal. Appl. 318 742-57 2007 Arch. ALGA 4 55-60). In Ibragimov (2007 J. Math. Anal. Appl. 333 311-28), a general theorem on conservation laws was proved. In this paper, we generalize the concept of self-adjoint and quasi self-adjoint equations by introducing the definition of weak self-adjoint equations. We find a class of weak self-adjoint quasi-linear parabolic equations. The property of a differential equation to be weak self-adjoint is important for constructing conservation laws associated with symmetries of the differential equation.

  10. Systematics of strength function sum rules

    SciTech Connect

    Johnson, Calvin W.

    2015-08-28

    Sum rules provide useful insights into transition strength functions and are often expressed as expectation values of an operator. In this letter I demonstrate that non-energy-weighted transition sum rules have strong secular dependences on the energy of the initial state. Such non-trivial systematics have consequences: the simplification suggested by the generalized Brink–Axel hypothesis, for example, does not hold for most cases, though it weakly holds in at least some cases for electric dipole transitions. Furthermore, I show the systematics can be understood through spectral distribution theory, calculated via traces of operators and of products of operators. Seen through this lens, violation of the generalized Brink–Axel hypothesis is unsurprising: one expectssum rules to evolve with excitation energy. Moreover, to lowest order the slope of the secular evolution can be traced to a component of the Hamiltonian being positive (repulsive) or negative (attractive).

  11. Systematics of strength function sum rules

    DOE PAGES

    Johnson, Calvin W.

    2015-08-28

    Sum rules provide useful insights into transition strength functions and are often expressed as expectation values of an operator. In this letter I demonstrate that non-energy-weighted transition sum rules have strong secular dependences on the energy of the initial state. Such non-trivial systematics have consequences: the simplification suggested by the generalized Brink–Axel hypothesis, for example, does not hold for most cases, though it weakly holds in at least some cases for electric dipole transitions. Furthermore, I show the systematics can be understood through spectral distribution theory, calculated via traces of operators and of products of operators. Seen through this lens,more » violation of the generalized Brink–Axel hypothesis is unsurprising: one expectssum rules to evolve with excitation energy. Moreover, to lowest order the slope of the secular evolution can be traced to a component of the Hamiltonian being positive (repulsive) or negative (attractive).« less

  12. Weak Acid Ionization Constants and the Determination of Weak Acid-Weak Base Reaction Equilibrium Constants in the General Chemistry Laboratory

    ERIC Educational Resources Information Center

    Nyasulu, Frazier; McMills, Lauren; Barlag, Rebecca

    2013-01-01

    A laboratory to determine the equilibrium constants of weak acid negative weak base reactions is described. The equilibrium constants of component reactions when multiplied together equal the numerical value of the equilibrium constant of the summative reaction. The component reactions are weak acid ionization reactions, weak base hydrolysis…

  13. Extrapolating Weak Selection in Evolutionary Games

    PubMed Central

    Wu, Bin; García, Julián; Hauert, Christoph; Traulsen, Arne

    2013-01-01

    In evolutionary games, reproductive success is determined by payoffs. Weak selection means that even large differences in game outcomes translate into small fitness differences. Many results have been derived using weak selection approximations, in which perturbation analysis facilitates the derivation of analytical results. Here, we ask whether results derived under weak selection are also qualitatively valid for intermediate and strong selection. By “qualitatively valid” we mean that the ranking of strategies induced by an evolutionary process does not change when the intensity of selection increases. For two-strategy games, we show that the ranking obtained under weak selection cannot be carried over to higher selection intensity if the number of players exceeds two. For games with three (or more) strategies, previous examples for multiplayer games have shown that the ranking of strategies can change with the intensity of selection. In particular, rank changes imply that the most abundant strategy at one intensity of selection can become the least abundant for another. We show that this applies already to pairwise interactions for a broad class of evolutionary processes. Even when both weak and strong selection limits lead to consistent predictions, rank changes can occur for intermediate intensities of selection. To analyze how common such games are, we show numerically that for randomly drawn two-player games with three or more strategies, rank changes frequently occur and their likelihood increases rapidly with the number of strategies . In particular, rank changes are almost certain for , which jeopardizes the predictive power of results derived for weak selection. PMID:24339769

  14. Electro-weak reactions for astrophysics

    SciTech Connect

    R. Schiavilla

    2000-06-01

    The status of ''ab initio'' microscopic calculations of the {sup 2}H(p,{gamma}){sup 3}He and {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He reactions is reviewed. The methods used to generate accurate nuclear ground- and scattering-state wave functions, and to construct realistic electro-weak transition operators are described. The uncertainties in the theoretical predictions, particularly those relevant to the p-{sup 3}He weak capture, are discussed. For the dp radiative capture, the theoretical results are compared with the TUNL data in the energy range 0--100 keV.

  15. Spectroscopy of a weakly isolated horizon

    NASA Astrophysics Data System (ADS)

    Chen, Ge-Rui; Huang, Yong-Chang

    2016-06-01

    The spectroscopy of a weakly isolated horizon has been investigated. We obtain an equally spaced entropy spectrum with its quantum equal to the one given by Bekenstein (Phys Rev D 7:2333, 1973). We demonstrate that the quantization of entropy and area is a generic property of horizons which exists in a wide class of spacetimes admitting weakly isolated horizons. Our method based on the tunneling method also indicates that the entropy quantum of black hole horizons is closely related to Hawking temperature.

  16. Weak Lie symmetry and extended Lie algebra

    SciTech Connect

    Goenner, Hubert

    2013-04-15

    The concept of weak Lie motion (weak Lie symmetry) is introduced. Applications given exhibit a reduction of the usual symmetry, e.g., in the case of the rotation group. In this context, a particular generalization of Lie algebras is found ('extended Lie algebras') which turns out to be an involutive distribution or a simple example for a tangent Lie algebroid. Riemannian and Lorentz metrics can be introduced on such an algebroid through an extended Cartan-Killing form. Transformation groups from non-relativistic mechanics and quantum mechanics lead to such tangent Lie algebroids and to Lorentz geometries constructed on them (1-dimensional gravitational fields).

  17. Simple understanding of quantum weak values

    NASA Astrophysics Data System (ADS)

    Qin, Lupei; Feng, Wei; Li, Xin-Qi

    2016-02-01

    In this work we revisit the important and controversial concept of quantum weak values, aiming to provide a simplified understanding to its associated physics and the origin of anomaly. Taking the Stern-Gerlach setup as a working system, we base our analysis on an exact treatment in terms of quantum Bayesian approach. We also make particular connection with a very recent work, where the anomaly of the weak values was claimed from the pure statistics in association with “disturbance” and “post-selection”, rather than the unique quantum nature. Our analysis resolves the related controversies through a clear and quantitative way.

  18. Simple understanding of quantum weak values

    PubMed Central

    Qin, Lupei; Feng, Wei; Li, Xin-Qi

    2016-01-01

    In this work we revisit the important and controversial concept of quantum weak values, aiming to provide a simplified understanding to its associated physics and the origin of anomaly. Taking the Stern-Gerlach setup as a working system, we base our analysis on an exact treatment in terms of quantum Bayesian approach. We also make particular connection with a very recent work, where the anomaly of the weak values was claimed from the pure statistics in association with “disturbance” and “post-selection”, rather than the unique quantum nature. Our analysis resolves the related controversies through a clear and quantitative way. PMID:26838670

  19. Compressive wavefront sensing with weak values.

    PubMed

    Howland, Gregory A; Lum, Daniel J; Howell, John C

    2014-08-11

    We demonstrate a wavefront sensor that unites weak measurement and the compressive-sensing, single-pixel camera. Using a high-resolution spatial light modulator (SLM) as a variable waveplate, we weakly couple an optical field's transverse-position and polarization degrees of freedom. By placing random, binary patterns on the SLM, polarization serves as a meter for directly measuring random projections of the wavefront's real and imaginary components. Compressive-sensing optimization techniques can then recover the wavefront. We acquire high quality, 256 × 256 pixel images of the wavefront from only 10,000 projections. Photon-counting detectors give sub-picowatt sensitivity.

  20. Critical level statistics for weakly disordered graphene.

    PubMed

    Amanatidis, E; Kleftogiannis, I; Katsanos, D E; Evangelou, S N

    2014-04-16

    In two dimensions chaotic level statistics with the Wigner spacing distribution P(S) is expected for massless fermions in the Dirac region. The obtained P(S) for weakly disordered finite graphene samples with zigzag edges turns out, however, to be neither chaotic (Wigner) nor localized (Poisson). It is similar to the intermediate statistics at the critical point of the Anderson metal-insulator transition. The quantum transport of finite graphene for weak disorder, with critical level statistics can occur via edge states as in topological insulators, and for strong disorder, graphene behaves as an ordinary Anderson insulator with Poisson statistics.

  1. The molecular basis of skeletal muscle weakness in a mouse model of inflammatory myopathy

    PubMed Central

    Coley, William; Rayavarapu, Sree; Pandey, Gouri S.; Sabina, Richard L.; vander Meulen, Jack H.; Ampong, Beryl; Wortmann, Robert L.; Rawat, Rashmi; Nagaraju, Kanneboyina

    2012-01-01

    OBJECTIVE It is generally believed that muscle weakness in patients with polymyositis and dermatomyositis is due to autoimmune and inflammatory processes. However, it has been observed that there is a poor correlation between the suppression of inflammation and a recovery of muscle function in patients. We have therefore hypothesized that non-immune mechanisms also contribute to muscle weakness. In particular, it has been suggested that an acquired deficiency of AMP deaminase (AMPD1) may be responsible for muscle weakness in myositis. METHODS We have used comprehensive functional, behavioral, histological, molecular, enzymatic and metabolic assessments before and after the onset of inflammation in MHC class I mouse model of autoimmune inflammatory myositis. RESULTS We found that muscle weakness and metabolic disturbances were detectable in the mice prior to the appearance of infiltrating mononuclear cells. Force contraction analysis of muscle function revealed that weakness was correlated with AMDP1 expression and was myositis-specific. We also demonstrated that decreasing AMPD1 expression results in decreased muscle strength in healthy mice. Fiber typing suggested that fast-twitch muscles are converted to slow-twitch muscles as myositis progresses, and microarray results indicated that AMPD1 and other purine nucleotide pathway genes are suppressed, along with genes essential to glycolysis. CONCLUSION These data suggest that an AMPD1 deficiency is acquired prior to overt muscle inflammation and is responsible, at least in part, for the muscle weakness that occurs in the mouse model of myositis. AMPD1 is therefore a potential therapeutic target in myositis. PMID:22806328

  2. Lithospheric strength variations in Mainland China: tectonic implications

    NASA Astrophysics Data System (ADS)

    Deng, Y.; Tesauro, M.

    2015-12-01

    We present new thermal and strength models of Mainland China. We integrate thermal model for the crust, using a 3D steady-state heat conduction equation, with estimates for the upper mantle thermal structure obtained by inverting an S-wave tomography model. Using the new thermal model and attributing to the lithospheric layers a 'soft' and 'hard' rheology, respectively, we estimate the integrated strength of the lithosphere. In the Ordos and the Sichuan basins, characterized by intermediate temperatures, strength is primarily concentrated in the crust, when the rheology is 'soft', and in both the crust and upper mantle, when the rheology is 'hard'. In turn, the Tibetan Plateau and the Tarim basin have a weak/strong lithosphere mainly on account of their high/low temperatures. Deep earthquakes releasing high seismic energy, occurring beneath Tien Shan orogen, may be related to the brittle failure of anhydrous granulite-faciesrocks composing its lower crust. In contrast, the fluids released by the Indian slab favor the triggering of earthquakes located in the deep crust of south Tibet. Comparison of temperatures, strength and effective viscosity variations with the earthquakes distribution and their seismic energy released indicates that both the deep part of the crust and the upper mantle of the Tibetan Plateau are weak and prone to flow towards the adjacent areas. On account of the high strength of some of the tectonic domains surrounding Tibet, the flow is directed northward beneath the Qaidam basin and turns south of the Sichuan basin, moving toward the weak South China block.

  3. Strength of Chemical Bonds

    NASA Technical Reports Server (NTRS)

    Christian, Jerry D.

    1973-01-01

    Students are not generally made aware of the extraordinary magnitude of the strengths of chemical bonds in terms of the forces required to pull them apart. Molecular bonds are usually considered in terms of the energies required to break them, and we are not astonished at the values encountered. For example, the Cl2 bond energy, 57.00 kcal/mole, amounts to only 9.46 x 10(sup -20) cal/molecule, a very small amount of energy, indeed, and impossible to measure directly. However, the forces involved in realizing the energy when breaking the bond operate over a very small distance, only 2.94 A, and, thus, f(sub ave) approx. equals De/(r - r(sub e)) must be very large. The forces involved in dissociating the molecule are discussed in the following. In consideration of average forces, the molecule shall be assumed arbitrarily to be dissociated when the atoms are far enough separated so that the potential, relative to that of the infinitely separated atoms, is reduced by 99.5% from the potential of the molecule at the equilibrium bond length (r(sub e)) for Cl2 of 1.988 A this occurs at 4.928 A.

  4. Cesium oscillator strengths measured with a multiple-path-length absorption cell

    NASA Technical Reports Server (NTRS)

    Exton, R. J.

    1976-01-01

    Absorption-oscillator-strength measurements for the principal series in cesium were measured using a multiple-path-length cell. The optical arrangement included a movable transverse path for checking the uniformity of the alkali density along the length of the cell and which also allowed strength measurements to be made simultaneously on both strong and weak lines. The strengths measured on the first 10 doublets indicate an increasing trend in the doublet ratio. The individual line strengths are in close agreement with the high resolution measurements of Pichler (1974) and with the calculations of Norcross (1973).

  5. Muscle weakness is related to slip-initiated falls among community-dwelling older adults.

    PubMed

    Ding, Li; Yang, Feng

    2016-01-25

    The purposes of this study were (1) to investigate the relationship between muscle weakness and slip-related falls among community-dwelling older adults, and (2) to determine optimal cut-off values with respect to the knee strength capacity which can be used to identify individuals at high risk of falls. Thirty-six healthy older adults participated in this study. Their muscle strength (torque) was assessed at the right knee under maximum voluntary isometric (flexion and extension) contractions. They were then moved to a special treadmill. After walking regularly five times on the treadmill, they experienced an identical and unannounced slip during walking on the treadmill with the protection of a safety harness. This treadmill could be considered a standardized platform, inducing an unexpected slip. Accuracy of predicting slip outcome (fall vs. recovery) was examined for both strength measurements (i.e., the strength capacity of knee extensor and flexor) using univariate logistic regressions. The optimal cutoff values for the two strength measurements were determined by the receiver operating characteristic analysis. Results showed that fallers displayed significantly lower knee strength capacities compared to their recovery counterpart (1.10 vs. 1.44Nm/kg, p<0.01, effect size Cohen׳s d=0.95 for extensor; 0.93 vs. 1.13Nm/kg, p<0.05, d=0.69 for flexor). Such results suggested that muscle weakness contributes to falls initiated by a slip during gait. Our findings could provide guidance to identify individuals at increased risk of falling using the derived optimal cutoff values of knee strength capacity among older adults.

  6. Reaction zone structure for strong, weak overdriven, and weak underdriven oblique detonations

    NASA Technical Reports Server (NTRS)

    Powers, Joseph M.; Gonthier, Keith A.

    1992-01-01

    A simple dynamic systems analysis is used to give examples of strong, weak overdriven, and weak underdriven oblique detonations. Steady oblique detonations consisting of a straight lead shock attached to a solid wedge followed by a resolved reaction zone structure are admitted as solutions to the reactive Euler equations. This is demonstrated for a fluid that is taken to be an inviscid, calorically perfect ideal gas that undergoes a two-step irreversible reaction with the first step exothermic and the second step endothermic. This model admits solutions for a continuum of shock wave angles for two classes of solutions identified by a Rankine-Hugoniot analysis: strong and weak overdriven waves. The other class, weak underdriven, is admitted for eigenvalue shock-wave angles. Chapman-Jouguet waves, however, are not admitted. These results contrast those for a corresponding onestep model that, for detonations with a straight lead shock, only admits strong, weak overdriven, and Chapman-Jouguet solutions.

  7. [A strong man with a weak shoulder].

    PubMed

    Henket, Marjolijn; Lycklama á Nijeholt, Geert J; van der Zwaal, Peer

    2013-01-01

    A 47-year-old former olympic athlete had pain and weakness of his left shoulder. There was no prior trauma. He had full range-of-motion and a scapular dyskinesia. There was atrophy of the trapezius and sternocleidomastoideus muscles. He was diagnosed with 'idiopathic neuritis of the accessorius nerve'. PMID:24326139

  8. Interaction barriers for light, weakly bound projectiles

    SciTech Connect

    Kolata, J. J.; Aguilera, E. F.

    2009-02-15

    A parametrization of the interaction-barrier model of C. Y. Wong [Phys. Rev. Lett. 31, 766 (1973)] is given for light, weakly bound projectiles and also for the exotic 'halo' nuclei {sup 6}He and {sup 8}B. Comparisons are made with the original parametrization. The extremely anomalous behavior of the interaction radius and barrier curvature for halo nuclei is discussed.

  9. Resource Letter WI-1: Weak Interactions

    ERIC Educational Resources Information Center

    Holstein, Barry R.

    1977-01-01

    Provides a listing of sources of literature and teaching aids to improve course content in the fields of: weak interactions, beta decay, orbital electron capture, muon capture, semileptonic decay, nonleptonic processes, parity violation in nuclei, neutrino physics, and parity violation in atomic physics. (SL)

  10. Weak radiative baryonic decays of B mesons

    SciTech Connect

    Kohara, Yoji

    2004-11-01

    Weak radiative baryonic B decays B{yields}B{sub 1}B{sub 2}-bar{gamma} are studied under the assumption of the short-distance b{yields}s{gamma} electromagnetic penguin transition dominance. The relations among the decay rates of various decay modes are derived.

  11. Quantum Signature Scheme with Weak Arbitrator

    NASA Astrophysics Data System (ADS)

    Luo, Ming-Xing; Chen, Xiu-Bo; Yun, Deng; Yang, Yi-Xian

    2012-07-01

    In this paper, we propose one quantum signature scheme with a weak arbitrator to sign classical messages. This scheme can preserve the merits in the original arbitrated scheme with some entanglement resources, and provide a higher efficiency in transmission and reduction the complexity of implementation. The arbitrator is costless and only involved in the disagreement case.

  12. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Weak. 51.894 Section 51.894 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT...

  13. Weak shock wave reflection from concave surfaces

    NASA Astrophysics Data System (ADS)

    Gruber, Sebastien; Skews, Beric

    2013-07-01

    The reflection of very weak shock waves from concave curved surfaces has not been well documented in the past, and recent studies have shown the possible existence of a variation in the accepted reflection configuration evolution as a shock wave encounters an increasing gradient on the reflecting surface. The current study set out to investigate this anomaly using high-resolution photography. Shock tube tests were done on various concave circular and parabolic geometries, all with zero initial ramp angle. Although the results have limitations due to the achievable image resolution, the results indicate that for very weak Mach numbers, M S < 1.1, there may be a region in which the reflection configuration resembles that of a regular reflection, unlike for the stronger shock wave case. This region exists after the triple point of the Mach reflection meets the reflecting surface and prior to the formation of the additional shock structures that represent a transitioned regular reflection. The Mach and transitioned regular reflections at 1.03 < M s < 1.05 also exhibit no signs of a visible shear layer, or a clear discontinuity at the triple point, and are thus also apparently different in the weak shock regime than what has been described for stronger shocks, similar to what has been shown for weak shocks reflecting off a plane wedge.

  14. Quantum trajectories based on the weak value

    NASA Astrophysics Data System (ADS)

    Mori, Takuya; Tsutsui, Izumi

    2015-04-01

    The notion of the trajectory of an individual particle is strictly inhibited in quantum mechanics because of the uncertainty principle. Nonetheless, the weak value, which has been proposed as a novel and measurable quantity definable to any quantum observable, can offer a possible description of trajectory on account of its statistical nature. In this paper, we explore the physical significance provided by this "weak trajectory" by considering various situations where interference takes place simultaneously with the observation of particles, that is, in prototypical quantum situations for which no classical treatment is available. These include the double slit experiment and Lloyd's mirror, where in the former case it is argued that the real part of the weak trajectory describes an average over the possible classical trajectories involved in the process, and that the imaginary part is related to the variation of interference. It is shown that this average interpretation of the weak trajectory holds universally under the complex probability defined from the given transition process. These features remain essentially unaltered in the case of Lloyd's mirror where interference occurs with a single slit.

  15. Transitivity, weakly mixing property and chaos

    NASA Astrophysics Data System (ADS)

    Wang, Lidong; Liang, Jianhua; Wang, Yiyi; Sun, Xuelian

    2016-01-01

    Let X be a compact metric space without isolated points and let f : X → X be a continuous map. In this paper, if (X,f) is a transitive dynamical system with a repelling periodic point, then f is chaotic in the sense of Kato. In addition, if f is weakly topologically mixing, then f is chaotic in the strong sense of Kato.

  16. Molecular Handshake: Recognition through Weak Noncovalent Interactions

    ERIC Educational Resources Information Center

    Murthy, Parvathi S.

    2006-01-01

    The weak noncovalent interactions between substances, the handshake in the form of electrostatic interactions, van der Waals' interactions or hydrogen bonding is universal to all living and nonliving matter. They significantly influence the molecular and bulk properties and behavior of matter. Their transient nature affects chemical reactions and…

  17. Modeling, Measuring, and Compensating Color Weak Vision

    NASA Astrophysics Data System (ADS)

    Oshima, Satoshi; Mochizuki, Rika; Lenz, Reiner; Chao, Jinhui

    2016-06-01

    We use methods from Riemann geometry to investigate transformations between the color spaces of color-normal and color weak observers. The two main applications are the simulation of the perception of a color weak observer for a color normal observer and the compensation of color images in a way that a color weak observer has approximately the same perception as a color normal observer. The metrics in the color spaces of interest are characterized with the help of ellipsoids defined by the just-noticable-differences between color which are measured with the help of color-matching experiments. The constructed mappings are isometries of Riemann spaces that preserve the perceived color-differences for both observers. Among the two approaches to build such an isometry, we introduce normal coordinates in Riemann spaces as a tool to construct a global color-weak compensation map. Compared to previously used methods this method is free from approximation errors due to local linearizations and it avoids the problem of shifting locations of the origin of the local coordinate system. We analyse the variations of the Riemann metrics for different observers obtained from new color matching experiments and describe three variations of the basic method. The performance of the methods is evaluated with the help of semantic differential (SD) tests.

  18. Chaotic weak chimeras and their persistence in coupled populations of phase oscillators

    NASA Astrophysics Data System (ADS)

    Bick, Christian; Ashwin, Peter

    2016-05-01

    Nontrivial collective behavior may emerge from the interactive dynamics of many oscillatory units. Chimera states are chaotic patterns of spatially localized coherent and incoherent oscillations. The recently-introduced notion of a weak chimera gives a rigorously testable characterization of chimera states for finite-dimensional phase oscillator networks. In this paper we give some persistence results for dynamically invariant sets under perturbations and apply them to coupled populations of phase oscillators with generalized coupling. In contrast to the weak chimeras with nonpositive maximal Lyapunov exponents constructed so far, we show that weak chimeras that are chaotic can exist in the limit of vanishing coupling between coupled populations of phase oscillators. We present numerical evidence that positive Lyapunov exponents can persist for a positive measure set of this inter-population coupling strength.

  19. Tensile strength of restorative resins.

    PubMed

    Zidan, O; Asmussen, E; Jørgensen, K D

    1980-06-01

    The purpose of the present work was to measure the tensile strength of restorative resins and to study the effect of the method of measurement on the recorded results. A direct pull method using dumb-bell shaped specimens was used. The tensile strength of the resins was also tested using the diametral compression method suggested by the A.D.A. It was found that the method of testing affects the results. Although the diametral compression method is a simple method, it cannot be considered reliable for all types of material. The tensile strength of the conventional composites was significantly higher than the tensile strength of the microfilled composites.

  20. Resolution of pronounced painless weakness arising from radiculopathy and disk extrusion.

    PubMed

    Lipetz, Jason S; Misra, Neelam; Silber, Jeff S

    2005-07-01

    In this retrospective, consecutive case series, we report the nonsurgical and rehabilitation outcomes of consecutive patients who presented with pronounced painless weakness arising from disk extrusion. Seven consecutive patients who chose physiatric care were followed clinically, and strength return was monitored. Each presented with predominantly painless radiculopathy, functionally significant strength loss, and radiographic evidence of disk extrusion or sequestration. Each patient participated in a targeted strengthening program, and in some cases, transforaminal injection therapy was employed. Each patient demonstrated an eventual full functional recovery. In most cases, electrodiagnostic studies were performed and included a needle examination of the affected limb and compound muscle action potentials from the most clinically relevant and weakened limb muscle. The electrodiagnostic findings and, in particular, the quantitative compound muscle action potential data seemed to correlate with the timing of motor recovery. Patients with predominantly painless and significant weakness arising from disk extrusion can demonstrate successful rehabilitation outcomes. Despite a relative absence of pain, such patients can present with a more rapidly reversible neurapraxic type of weakness. The more quantitative compound muscle action potential data obtained through electrodiagnostic studies may offer the treating physician an additional means of characterizing the type of neuronal injury at play and the likelihood and timing of strength return. PMID:15973090

  1. Physiological Effects of Strength Training and Various Strength Training Devices.

    ERIC Educational Resources Information Center

    Wilmore, Jack H.

    Current knowledge in the area of muscle physiology is a basis for a discussion on strength training programs. It is now recognized that the expression of strength is related to, but not dependent upon, the size of the muscle and is probably more related to the ability to recruit more muscle fibers in the contraction, or to better synchronize their…

  2. Autaptic pacemaker mediated propagation of weak rhythmic activity across small-world neuronal networks

    NASA Astrophysics Data System (ADS)

    Yilmaz, Ergin; Baysal, Veli; Ozer, Mahmut; Perc, Matjaž

    2016-02-01

    We study the effects of an autapse, which is mathematically described as a self-feedback loop, on the propagation of weak, localized pacemaker activity across a Newman-Watts small-world network consisting of stochastic Hodgkin-Huxley neurons. We consider that only the pacemaker neuron, which is stimulated by a subthreshold periodic signal, has an electrical autapse that is characterized by a coupling strength and a delay time. We focus on the impact of the coupling strength, the network structure, the properties of the weak periodic stimulus, and the properties of the autapse on the transmission of localized pacemaker activity. Obtained results indicate the existence of optimal channel noise intensity for the propagation of the localized rhythm. Under optimal conditions, the autapse can significantly improve the propagation of pacemaker activity, but only for a specific range of the autaptic coupling strength. Moreover, the autaptic delay time has to be equal to the intrinsic oscillation period of the Hodgkin-Huxley neuron or its integer multiples. We analyze the inter-spike interval histogram and show that the autapse enhances or suppresses the propagation of the localized rhythm by increasing or decreasing the phase locking between the spiking of the pacemaker neuron and the weak periodic signal. In particular, when the autaptic delay time is equal to the intrinsic period of oscillations an optimal phase locking takes place, resulting in a dominant time scale of the spiking activity. We also investigate the effects of the network structure and the coupling strength on the propagation of pacemaker activity. We find that there exist an optimal coupling strength and an optimal network structure that together warrant an optimal propagation of the localized rhythm.

  3. Extraversion, neuroticism and strength of the nervous system.

    PubMed

    Frigon, J Y

    1976-11-01

    The hypothesized identity of the dimensions of extraversion-introversion and strength of the nervous system was tested on four groups of nine subjects (neurotic extraverts, stable extraverts, neurotic introverts, stable introverts). Strength of the subjects' nervous system was estimated using the electroencephalographic (EEG) variant of extinction with reinforcement. Introverted subjects were found to have weak nervous systems, according to the EEG index, while extraverted subjects had strong nervous systems, thus confirming the hypothesis. It was also found that the dimension of strength of the nervous system was unrelated to differences in neuroticism. The results are interpreted as adding support to Eysenck's theory relating differences in extraversion-introversion to differences in cortical arousal.

  4. Bats Respond to Very Weak Magnetic Fields

    PubMed Central

    Tian, Lan-Xiang; Pan, Yong-Xin; Metzner, Walter; Zhang, Jin-Shuo; Zhang, Bing-Fang

    2015-01-01

    How animals, including mammals, can respond to and utilize the direction and intensity of the Earth’s magnetic field for orientation and navigation is contentious. In this study, we experimentally tested whether the Chinese Noctule, Nyctalus plancyi (Vespertilionidae) can sense magnetic field strengths that were even lower than those of the present-day geomagnetic field. Such field strengths occurred during geomagnetic excursions or polarity reversals and thus may have played an important role in the evolution of a magnetic sense. We found that in a present-day local geomagnetic field, the bats showed a clear preference for positioning themselves at the magnetic north. As the field intensity decreased to only 1/5th of the natural intensity (i.e., 10 μT; the lowest field strength tested here), the bats still responded by positioning themselves at the magnetic north. When the field polarity was artificially reversed, the bats still preferred the new magnetic north, even at the lowest field strength tested (10 μT), despite the fact that the artificial field orientation was opposite to the natural geomagnetic field (P<0.05). Hence, N. plancyi is able to detect the direction of a magnetic field even at 1/5th of the present-day field strength. This high sensitivity to magnetic fields may explain how magnetic orientation could have evolved in bats even as the Earth’s magnetic field strength varied and the polarity reversed tens of times over the past fifty million years. PMID:25922944

  5. Causal conjunction fallacies: the roles of causal strength and mental resources.

    PubMed

    Crisp, Aimée Kay; Feeney, Aidan

    2009-12-01

    In two experiments we tested the prediction derived from Tversky and Kahneman's (1983) work on the causal conjunction fallacy that the strength of the causal connection between constituent events directly affects the magnitude of the causal conjunction fallacy. We also explored whether any effects of perceived causal strength were due to graded output from heuristic Type 1 reasoning processes or the result of analytic Type 2 reasoning processes. As predicted, Experiment 1 demonstrated that fallacy rates were higher for strongly than for weakly related conjunctions. Weakly related conjunctions in turn attracted higher rates of fallacious responding than did unrelated conjunctions. Experiment 2 showed that a concurrent memory load increased rates of fallacious responding for strongly related but not for weakly related conjunctions. We interpret these results as showing that manipulations of the strength of the perceived causal relationship between the conjuncts result in graded output from heuristic reasoning process and that additional mental resources are required to suppress strong heuristic output.

  6. Frictional Strength of Hayward Fault Gouge

    NASA Astrophysics Data System (ADS)

    Morrow, C.; Moore, D.; Lockner, D.

    2007-12-01

    A recent 3-D geologic model of the Hayward fault in the San Francisco Bay Region shows that a number of different rock units are juxtaposed across the fault surface as a result of lateral displacement. The fault gouge formed therein is likely a mixture of these various rock types. To better model the mechanical behavior of the Hayward fault, which is known to both creep and have large earthquakes, frictional properties of mixtures of the principal rock types were determined in the laboratory. Room temperature triaxial shearing tests were conducted on binary and ternary mixtures of Great Valley Sequence graywacke, Franciscan jadeite-bearing metagraywacke, Franciscan pumpellyite-bearing metasandstone, Franciscan melange matrix, serpentinite and two-pyroxene gabbro. The gouge samples were crushed and sieved (<150 μm grains), then applied in a 1-mm layer between saw-cut sliding blocks. Each sample assemblage was saturated and sheared at constant pore water pressure of 1 MPa and normal stress of 51 MPa. Coefficients of friction, μ, ranged from a low of 0.38 for the serpentinite to a maximum of 0.85 for the gabbro. While the serpentinite and the Franciscan melange matrix were relatively weak, all other rock types obeyed Byerlee's Law. The friction coefficient of mixtures could be reliably predicted by a simple average based on dry weight percent of the end member strengths. This behavior is in contrast to some mixtures of common gouge materials such as montmorillonite+quartz, which exhibit non- linear frictional strength trends with varying weight percent of constituents. All materials tested except serpentinite were velocity strengthening, therefore promoting creeping behavior. The addition of serpentinite decreased a-b values of the gouge and increased the characteristic displacement, dc, of strength evolution. Because temperature strongly influences the mechanical properties of fault gouge as well as speeding chemical reactions between the constituents, elevated

  7. The weak measurement process and the weak value of spin for metastable helium 23S1

    NASA Astrophysics Data System (ADS)

    Monachello, Vincenzo; Barker, Peter; Flack, Robert; Hiley, Basil

    2016-05-01

    An experiment is being designed and constructed in order to measure the weak value of spin for an atomic system. The principle of the ``weak measurement'' process was first proposed by Aharonov, Albert and Vaidman, and describes a scenario in which a system is weakly coupled to a pointer between well-defined pre- and post-selected states. This experiment will utilise a pulsed supersonic beam of spin-1 metastable Helium (He*) atoms in the 23S1 state. The spin of the pre-selected He* atoms will be weakly coupled to its centre-of-mass. During its flight, the atomic beam will be prepared in a desired quantum state and travel through two inhomogeneous magnets (weak and strong) which both comprise the ``weak measurement'' process. The deviation of the post-selected ms = + 1 state as measured using a micro-channel plate, phosphor screen and CCD camera setup will allow for the determination of the weak value of spin. This poster will report on the methods used and the experimental realisation.

  8. Weak Gravitatational Lensing by Illustris-1 Galaxies

    NASA Astrophysics Data System (ADS)

    Brainerd, Tereasa G.; Koh, Patrick H.

    2016-06-01

    We compute the weak gravitational lensing signal of isolated, central galaxies obtained from the z=0.5 timestep of the ΛCDM Illustris-1 simulation. The galaxies have stellar masses ranging from 9.5 ≤ log10(M*/Msun) ≤ 11.0 and are located outside cluster and rich group environments. Although there is local substructure present in the form of small, luminous satellite galaxies, the central galaxies are the dominant objects within the virial radii (r200), and each central galaxy is at least 5 times brighter than any other luminous galaxy within the friends-of-friends halo. We compute the weak lensing signal within projected radii 0.05 < rp/r200 < 1.5 and investigate the degree to which the weak lensing signal is anisotropic. Since CDM halos are non-spherical, the weak lensing signal is expected to be anisotropic; however, the degree of anisotropy that is observed depends upon the symmetry axes that are used to define the geometry. The anisotropy is expected to be maximized when the major axis of the projected dark matter mass distribution is used to define the geomety. In practice in the observed universe, one must necessarily use the projected distribution of the luminous mass to define the geometry. If mass and light are not well-aligned, this results in a suppression of the weak lensing anistropy. Our initial analysis shows that the ellipticity of the projected dark matter halo is uncorrelated with the ellipticity of the projected stellar mass. That is ɛhalo ≠ f × ɛlight, where f is a constant multiplicative factor. In addition, in projection on the sky, the major axis of the dark matter mass is offset from that of the stellar mass by ˜40o on average. On scales rp ≤ 0.15 r200, the weak lensing anisotropy obtained when using the stellar mass to define the geometry is of order 7% and agrees well with the anisotropy obtained when using the dark matter mass to define the geometry. On scales rp ˜ r200, the anisotropy obtained when using the stellar mass to

  9. Strength Training for Young Athletes.

    ERIC Educational Resources Information Center

    Kraemer, William J.; Fleck, Steven J.

    This guide is designed to serve as a resource for developing strength training programs for children. Chapter 1 uses research findings to explain why strength training is appropriate for children. Chapter 2 explains some of the important physiological concepts involved in children's growth and development as they apply to developing strength…

  10. Hip abductor weakness is not the cause for iliotibial band syndrome.

    PubMed

    Grau, S; Krauss, I; Maiwald, C; Best, R; Horstmann, T

    2008-07-01

    Muscular deficits in the hip abductors are presumed to be a major factor in the development of Iliotibial Band Syndrome in runners. No definite relationship between muscular weakness of the hip abductors and the development of Iliotibial Band Syndrome or different ratios between hip adduction to abduction have been reported so far. Isokinetic measurements were taken from 10 healthy runners and 10 runners with Iliotibial Band Syndrome. Primary outcome variables were concentric, eccentric, and isometric peak torque of the hip abductors and adductors at 30 degrees/s, and a concentric endurance quotient at the same angle velocity. Differences in muscle strength of the hip abductors between healthy (CO) and injured runners (ITBS) were not statistically significant in any of the muscle functions tested. Both groups showed the same strength differences between hip adduction and abduction, and increased strength in hip adduction. Weakness of hip abductors does not seem to play a role in the etiology of Iliotibial Band Syndrome in runners, since dynamic and static strength measurements did not differ between groups, and differences between hip abduction and adduction were the same. Strengthening of hip abductors seems to have little effect on the prevention of Iliotibial Band Syndrome in runners.

  11. Strength properties of fly ash based controlled low strength materials.

    PubMed

    Türkel, S

    2007-08-25

    Controlled low strength material (CLSM) is a flowable mixture that can be used as a backfill material in place of compacted soils. Flowable fill requires no tamping or compaction to achieve its strength and typically has a load carrying capacity much higher than compacted soils, but it can still be excavated easily. The selection of CLSM type should be based on technical and economical considerations for specific applications. In this study, a mixture of high volume fly ash (FA), crushed limestone powder (filler) and a low percentage of pozzolana cement have been tried in different compositions. The amount of pozzolana cement was kept constant for all mixes as, 5% of fly ash weight. The amount of mixing water was chosen in order to provide optimum pumpability by determining the spreading ratio of CLSM mixtures using flow table method. The shear strength of the material is a measure of the materials ability to support imposed stresses on the material. The shear strength properties of CLSM mixtures have been investigated by a series of laboratory tests. The direct shear test procedure was applied for determining the strength parameters Phi (angle of shearing resistance) and C(h) (cohesion intercept) of the material. The test results indicated that CLSM mixtures have superior shear strength properties compared to compacted soils. Shear strength, cohesion intercept and angle of shearing resistance values of CLSM mixtures exceeded conventional soil materials' similar properties at 7 days. These parameters proved that CLSM mixtures are suitable materials for backfill applications.

  12. Weakly nonlinear hydrodynamic instabilities in inertial fusion

    SciTech Connect

    Haan, S.W. )

    1991-08-01

    For many cases of interest to inertial fusion, growth of Rayleigh--Taylor and other hydrodynamic instabilities is such that the perturbations remain linear or weakly nonlinear. The transition to nonlinearity is studied via a second-order solution for multimode classical Rayleigh--Taylor growth. The second-order solution shows how classical Rayleigh--Taylor systems forget initial amplitude information in the weakly nonlinear phase. Stabilized growth relevant to inertial fusion is qualitatively different, and initial amplitudes are not dominated by nonlinear effects. In all systems with a full spectrum of modes, nonlinear effects begin when mode amplitudes reach about 1/{ital Lk}{sup 2}, for modes of wave number {ital k} and system size {ital L}.

  13. Weak Energy Condition Violation and Superluminal Travel

    NASA Astrophysics Data System (ADS)

    Lobo, Francisco; Crawford, Paulo

    Recent solutions to the Einstein Field Equations involving negative energy densities, i.e., matter violating the weak-energy-condition, have been obtained, namely traversable wormholes, the Alcubierre warp drive and the Krasnikov tube. These solutions are related to superluminal travel, although locally the speed of light is not surpassed. It is difficult to define faster-than-light travel in generic space-times, and one can construct metrics which apparently allow superluminal travel, but are in fact flat Minkowski space-times. Therefore, to avoid these difficulties it is important to provide an appropriate definition of superluminal travel.We investigate these problems and the relationship between weak-energy-condition violation and superluminal travel.

  14. Crystallographic Phasing from Weak Anomalous Signals

    PubMed Central

    Liu, Qun; Hendrickson, Wayne A.

    2015-01-01

    The exploitation of anomalous signals for biological structural solution is maturing. Single-wavelength anomalous diffraction (SAD) is dominant in de novo structure analysis. Nevertheless, for challenging structures where the resolution is low (dmin ≥ 3.5 Å) or where only lighter atoms (Z ≤ 20) are present, as for native macromolecules, solved SAD structures are still scarce. With the recent rapid development in crystal handling, beamline instrumentation, optimization of data collection strategies, use of multiple crystals and structure determination technologies, the weak anomalous diffraction signals are now robustly measured and should be used for routine SAD structure determination. The review covers these recent advances on weak anomalous signals measurement, analysis and utilization. PMID:26432413

  15. Amplification effects in optomechanics via weak measurements

    NASA Astrophysics Data System (ADS)

    Li, Gang; Wang, Tao; Song, He-Shan

    2014-07-01

    We revisit the scheme of single-photon weak-coupling optomechanics using postselection, proposed by Pepper, Ghobadi, Jeffrey, Simon, and Bouwmeester [Phys. Rev. Lett. 109, 023601 (2012), 10.1103/PhysRevLett.109.023601], by analyzing the exact solution of the dynamical evolution. Positive and negative amplification effects of the displacement of the mirror's position can be generated when the Kerr phase is considered. This effect occurs when the postselected state of the photon is orthogonal to the initial state, which cannot be explained by the usual weak measurement results. The amplification effect can be further modulated by a phase shifter, and the maximal displacement state can appear within a short evolution time.

  16. Weak cosmic censorship: as strong as ever.

    PubMed

    Hod, Shahar

    2008-03-28

    Spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. This is the essence of the weak cosmic censorship conjecture. The hypothesis, put forward by Penrose 40 years ago, is still one of the most important open questions in general relativity. In this Letter, we reanalyze extreme situations which have been considered as counterexamples to the weak cosmic censorship conjecture. In particular, we consider the absorption of scalar particles with large angular momentum by a black hole. Ignoring back reaction effects may lead one to conclude that the incident wave may overspin the black hole, thereby exposing its inner singularity to distant observers. However, we show that when back reaction effects are properly taken into account, the stability of the black-hole event horizon is irrefutable. We therefore conclude that cosmic censorship is actually respected in this type of gedanken experiments.

  17. Shock Wave Dynamics in Weakly Ionized Plasmas

    NASA Technical Reports Server (NTRS)

    Johnson, Joseph A., III

    1999-01-01

    An investigation of the dynamics of shock waves in weakly ionized argon plasmas has been performed using a pressure ruptured shock tube. The velocity of the shock is observed to increase when the shock traverses the plasma. The observed increases cannot be accounted for by thermal effects alone. Possible mechanisms that could explain the anomalous behavior include a vibrational/translational relaxation in the nonequilibrium plasma, electron diffusion across the shock front resulting from high electron mobility, and the propagation of ion-acoustic waves generated at the shock front. Using a turbulence model based on reduced kinetic theory, analysis of the observed results suggest a role for turbulence in anomalous shock dynamics in weakly ionized media and plasma-induced hypersonic drag reduction.

  18. Weak cosmic censorship: as strong as ever.

    PubMed

    Hod, Shahar

    2008-03-28

    Spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. This is the essence of the weak cosmic censorship conjecture. The hypothesis, put forward by Penrose 40 years ago, is still one of the most important open questions in general relativity. In this Letter, we reanalyze extreme situations which have been considered as counterexamples to the weak cosmic censorship conjecture. In particular, we consider the absorption of scalar particles with large angular momentum by a black hole. Ignoring back reaction effects may lead one to conclude that the incident wave may overspin the black hole, thereby exposing its inner singularity to distant observers. However, we show that when back reaction effects are properly taken into account, the stability of the black-hole event horizon is irrefutable. We therefore conclude that cosmic censorship is actually respected in this type of gedanken experiments. PMID:18517851

  19. Security Weaknesses in Arbitrated Quantum Signature Protocols

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Zhang, Kejia; Cao, Tianqing

    2014-01-01

    Arbitrated quantum signature (AQS) is a cryptographic scenario in which the sender (signer), Alice, generates the signature of a message and then a receiver (verifier), Bob, can verify the signature with the help of a trusted arbitrator, Trent. In this paper, we point out there exist some security weaknesses in two AQS protocols. Our analysis shows Alice can successfully disavow any of her signatures by a simple attack in the first protocol. Furthermore, we study the security weaknesses of the second protocol from the aspects of forgery and disavowal. Some potential improvements of this kind of protocols are given. We also design a new method to authenticate a signature or a message, which makes AQS protocols immune to Alice's disavowal attack and Bob's forgery attack effectively.

  20. An algorithm for multivariate weak stochastic dominance

    SciTech Connect

    Mosler, K.

    1994-12-31

    The talk addresses the computational problem of comparing two given probability distributions in n-space with respect to several stochastic orderings. The orderings investigated are weak first degree stochastic dominance, weak second degree stochastic dominance, and their dual ordering relations. For each of the four dominance relations we present conditions which are necessary and sufficient for dominance of F over G when F and G have finite support in n-space. An algorithm is proposed which operates efficiently on the join-semilattice generated by their joint support. If F and G are empirical distribution functions, and {anti F} and {anti G}denote the underlying probability laws, significance tests can be performed on {anti F} = {anti G} against the alternative that {anti F} {ne} {anti G} and {anti F} dominates {anti G} in one of the four orderings. Other applications are found in decision theory, applied probability, operations research, and economics.

  1. Weak Cosmic Censorship: As Strong as Ever

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2008-03-01

    Spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. This is the essence of the weak cosmic censorship conjecture. The hypothesis, put forward by Penrose 40 years ago, is still one of the most important open questions in general relativity. In this Letter, we reanalyze extreme situations which have been considered as counterexamples to the weak cosmic censorship conjecture. In particular, we consider the absorption of scalar particles with large angular momentum by a black hole. Ignoring back reaction effects may lead one to conclude that the incident wave may overspin the black hole, thereby exposing its inner singularity to distant observers. However, we show that when back reaction effects are properly taken into account, the stability of the black-hole event horizon is irrefutable. We therefore conclude that cosmic censorship is actually respected in this type of gedanken experiments.

  2. Towards weakly constrained double field theory

    NASA Astrophysics Data System (ADS)

    Lee, Kanghoon

    2016-08-01

    We show that it is possible to construct a well-defined effective field theory incorporating string winding modes without using strong constraint in double field theory. We show that X-ray (Radon) transform on a torus is well-suited for describing weakly constrained double fields, and any weakly constrained fields are represented as a sum of strongly constrained fields. Using inverse X-ray transform we define a novel binary operation which is compatible with the level matching constraint. Based on this formalism, we construct a consistent gauge transform and gauge invariant action without using strong constraint. We then discuss the relation of our result to the closed string field theory. Our construction suggests that there exists an effective field theory description for massless sector of closed string field theory on a torus in an associative truncation.

  3. Disordered weak and strong topological insulators.

    PubMed

    Kobayashi, Koji; Ohtsuki, Tomi; Imura, Ken-Ichiro

    2013-06-01

    A global phase diagram of disordered weak and strong topological insulators is established numerically. As expected, the location of the phase boundaries is renormalized by disorder, a feature recognized in the study of the so-called topological Anderson insulator. Here, we report unexpected quantization, i.e., robustness against disorder of the conductance peaks on these phase boundaries. Another highlight of the work is on the emergence of two subregions in the weak topological insulator phase under disorder. According to the size dependence of the conductance, the surface states are either robust or "defeated" in the two subregions. The nature of the two distinct types of behavior is further revealed by studying the Lyapunov exponents.

  4. From weak discontinuities to nondissipative shock waves

    SciTech Connect

    Garifullin, R. N. Suleimanov, B. I.

    2010-01-15

    An analysis is presented of the effect of weak dispersion on transitions from weak to strong discontinuities in inviscid fluid dynamics. In the neighborhoods of transition points, this effect is described by simultaneous solutions to the Korteweg-de Vries equation u{sub t}'+ uu{sub x}' + u{sub xxx}' = 0 and fifth-order nonautonomous ordinary differential equations. As x{sup 2} + t{sup 2} {yields}{infinity}, the asymptotic behavior of these simultaneous solutions in the zone of undamped oscillations is given by quasi-simple wave solutions to Whitham equations of the form r{sub i}(t, x) = tl{sub i} x/t{sup 2}.

  5. Mutual synchronization of weakly coupled gyrotrons

    SciTech Connect

    Rozental, R. M.; Glyavin, M. Yu.; Sergeev, A. S.; Zotova, I. V.; Ginzburg, N. S.

    2015-09-15

    The processes of synchronization of two weakly coupled gyrotrons are studied within the framework of non-stationary equations with non-fixed longitudinal field structure. With the allowance for a small difference of the free oscillation frequencies of the gyrotrons, we found a certain range of parameters where mutual synchronization is possible while a high electronic efficiency is remained. It is also shown that synchronization regimes can be realized even under random fluctuations of the parameters of the electron beams.

  6. Acute neuromuscular weakness associated with dengue infection

    PubMed Central

    Hira, Harmanjit Singh; Kaur, Amandeep; Shukla, Anuj

    2012-01-01

    Background: Dengue infections may present with neurological complications. Whether these are due to neuromuscular disease or electrolyte imbalance is unclear. Materials and Methods: Eighty-eight patients of dengue fever required hospitalization during epidemic in year 2010. Twelve of them presented with acute neuromuscular weakness. We enrolled them for study. Diagnosis of dengue infection based on clinical profile of patients, positive serum IgM ELISA, NS1 antigen, and sero-typing. Complete hemogram, kidney and liver functions, serum electrolytes, and creatine phosphokinase (CPK) were tested. In addition, two patients underwent nerve conduction velocity (NCV) test and electromyography. Results: Twelve patients were included in the present study. Their age was between 18 and 34 years. Fever, myalgia, and motor weakness of limbs were most common presenting symptoms. Motor weakness developed on 2nd to 4th day of illness in 11 of 12 patients. In one patient, it developed on 10th day of illness. Ten of 12 showed hypokalemia. One was of Guillain-Barré syndrome and other suffered from myositis; they underwent NCV and electromyography. Serum CPK and SGOT raised in 8 out of 12 patients. CPK of patient of myositis was 5098 IU. All of 12 patients had thrombocytopenia. WBC was in normal range. Dengue virus was isolated in three patients, and it was of serotype 1. CSF was normal in all. Within 24 hours, those with hypokalemia recovered by potassium correction. Conclusions: It was concluded that the dengue virus infection led to acute neuromuscular weakness because of hypokalemia, myositis, and Guillain-Barré syndrome. It was suggested to look for presence of hypokalemia in such patients. PMID:22346188

  7. Heat capacity in weakly correlated liquids

    SciTech Connect

    Khrustalyov, Yu. V.; Vaulina, O. S.; Koss, X. G.

    2012-12-15

    Previously unavailable numerical data related to the heat capacity in two- and three-dimensional liquid Yukawa systems are obtained by means of fluctuation theory. The relations between thermal conductivity and diffusion constants are numerically studied and discussed. New approximation for heat capacity dependence on non-ideality parameter for weakly correlated systems of particles is proposed. Comparison of the obtained results to the existing theoretical and numerical data is discussed.

  8. Exclusive processes in strong and weak interactions

    SciTech Connect

    Tsokos, K.

    1983-01-01

    Evolution equations for flavor singlet mesons are derived; these are solved in terms of Gegenbauer polynomials. These results have been applied to exclusive processes at large momentum transfer which involve flavor singlet mesons and glueballs - two glueball decays of the Upsilon, radiative psi decays and two-photon processes involving the eta. Exclusive, weak decays of heavy mesons are examined and the heavy mass scaling behavior of decay rates is obtained.

  9. Weakly bound states in heterogeneous waveguides

    NASA Astrophysics Data System (ADS)

    Amore, Paolo; Fernández, Francisco M.; Hofmann, Christoph P.

    2016-07-01

    We study the spectrum of the Helmholtz equation in a two-dimensional infinite waveguide, containing a weak heterogeneity localized at an internal point, and obeying Dirichlet boundary conditions at its border. We use the variational theorem to derive the condition for which the lowest eigenvalue of the spectrum falls below the continuum threshold and a bound state appears, localized at the heterogeneity. We devise a rigorous perturbation scheme and derive the exact expression for the energy to third order in the heterogeneity.

  10. Measuring neutrino masses with weak lensing

    SciTech Connect

    Wong, Yvonne Y. Y.

    2006-11-17

    Weak gravitational lensing of distant galaxies by large scale structure (LSS) provides an unbiased way to map the matter distribution in the low redshift universe. This technique, based on the measurement of small distortions in the images of the source galaxies induced by the intervening LSS, is expected to become a key cosmological probe in the future. We discuss how future lensing surveys can probe the sum of the neutrino masses at the 0 05 eV level.

  11. [Weak signal detection in every heart cycle].

    PubMed

    Yuan, J; Xu, X; Gao, D; Shi, G

    2001-12-01

    In this article, a new approach is introduced to lowering the myo-electronic noise in weak ECG signals. We use artificial neural network to make the noise be white, and then we adopt an adaptive filter of which the reference signal is achieved by extracting from other ECG cycle. The outcome is the reduction of both white noise and non-white noise in ECG signal. Satisfactory results have been achieved by using this method in the experiment of late potential detection.

  12. Longitudinal assessment of grip strength using bulb dynamometer in Duchenne Muscular Dystrophy

    PubMed Central

    Pizzato, Tatiana M.; Baptista, Cyntia R. J. A.; Souza, Mariana A.; Benedicto, Michelle M. B.; Martinez, Edson Z.; Mattiello-Sverzut, Ana C.

    2014-01-01

    BACKGROUND: Grip strength is used to infer functional status in several pathological conditions, and the hand dynamometer has been used to estimate performance in other areas. However, this relationship is controversial in neuromuscular diseases and studies with the bulb dynamometer comparing healthy children and children with Duchenne Muscular Dystrophy (DMD) are limited. OBJECTIVE: The evolution of grip strength and the magnitude of weakness were examined in boys with DMD compared to healthy boys. The functional data of the DMD boys were correlated with grip strength. METHOD: Grip strength was recorded in 18 ambulant boys with DMD (Duchenne Group, DG) aged 4 to 13 years (mean 7.4±2.1) and 150 healthy volunteers (Control Group, CG) age-matched using a bulb dynamometer (North Coast- NC70154). The follow-up of the DG was 6 to 33 months (3-12 sessions), and functional performance was verified using the Vignos scale. RESULTS: There was no difference between grip strength obtained by the dominant and non-dominant side for both groups. Grip strength increased in the CG with chronological age while the DG remained stable or decreased. The comparison between groups showed significant difference in grip strength, with CG values higher than DG values (confidence interval of 95%). In summary, there was an increment in the differences between the groups with increasing age. Participants with 24 months or more of follow-up showed a progression of weakness as well as maintained Vignos scores. CONCLUSIONS: The amplitude of weakness increased with age in the DG. The bulb dynamometer detected the progression of muscular weakness. Functional performance remained virtually unchanged in spite of the increase in weakness. PMID:25003277

  13. Ultra-weak photon emission of hands in aging prediction.

    PubMed

    Zhao, Xin; van Wijk, Eduard; Yan, Yu; van Wijk, Roeland; Yang, Huanming; Zhang, Yan; Wang, Jian

    2016-09-01

    Aging has been one of the several topics intensely investigated during recent decades. More scientists have been scrutinizing mechanisms behind the human aging process. Ultra-weak photon emission is known as one type of spontaneous photon emission that can be detected with a highly sensitive single photon counting photomultiplier tube (PMT) from the surface of human bodies. It may reflect the body's oxidative damage. Our aim was to examine whether ultra-weak photon emission from a human hand is able to predict one's chronological age. Sixty subjects were recruited and grouped by age. We examined four areas of each hand: palm side of fingers, palm side of hand, dorsum side of fingers, and dorsum side of hand. Left and right hand were measured synchronously with two independent PMTs. Mean strength and Fano factor values of photon counts were utilized to compare the UPE patterns of males and females of different age groups. Subsequently, we utilized UPE data from the most sensitive PMT to develop an age prediction model. We randomly picked 49 subjects to construct the model, whereas the remaining 11 subjects were utilized for validation. The results demonstrated that the model was a good regression compared to the observed values (Pearson's r=0.6, adjusted R square=0.4, p=9.4E-7, accuracy=49/60). Further analysis revealed that the average difference between the chronological age and predicted age was only 7.6±0.8years. It was concluded that this fast and non-invasive photon technology is sufficiently promising to be developed for the estimation of biological aging. PMID:27472904

  14. How we built a strong company in a weak industry.

    PubMed

    Brown, R

    2001-02-01

    When Roger Brown and Linda Mason decided to start a child care and early-education company 15 years ago, they knew about the challenges inherent in the industry: no barriers to entry, low margins, few economies of scale, heavy regulatory oversight--to name just a few. But that didn't stop them. They eventually built Bright Horizons Family Solutions, a company that now has more than 340 high-quality child care centers, serving 40,000 children and employing 12,000 people. How did they do it? Sheer determination helped. But even more important, they developed a business model that took advantage of industry weaknesses. When the couple sat down to hash out a plan for the company, they realized that the key to achieving profitability and creating barriers to entry was to partner with companies. They could achieve higher returns by having those companies build and outfit the centers and, at the same time, boost customer loyalty. Indeed, Bright Horizon's corporate clients came to see the state-of-the-art centers as a way to distinguish themselves in the eyes of current and prospective employees. The high-quality child care attracted the best employees and raised retention rates. Brown's first-person account describes the difficulties the couple and their company faced along the way, including the struggle for funding and a board that questioned Bright Horizons' business model and basic philosophy of good child care. But, Brown says, the commitment to a singular business model and the determination to make strengths out of weaknesses made the impossible possible.

  15. Ultra-weak photon emission of hands in aging prediction.

    PubMed

    Zhao, Xin; van Wijk, Eduard; Yan, Yu; van Wijk, Roeland; Yang, Huanming; Zhang, Yan; Wang, Jian

    2016-09-01

    Aging has been one of the several topics intensely investigated during recent decades. More scientists have been scrutinizing mechanisms behind the human aging process. Ultra-weak photon emission is known as one type of spontaneous photon emission that can be detected with a highly sensitive single photon counting photomultiplier tube (PMT) from the surface of human bodies. It may reflect the body's oxidative damage. Our aim was to examine whether ultra-weak photon emission from a human hand is able to predict one's chronological age. Sixty subjects were recruited and grouped by age. We examined four areas of each hand: palm side of fingers, palm side of hand, dorsum side of fingers, and dorsum side of hand. Left and right hand were measured synchronously with two independent PMTs. Mean strength and Fano factor values of photon counts were utilized to compare the UPE patterns of males and females of different age groups. Subsequently, we utilized UPE data from the most sensitive PMT to develop an age prediction model. We randomly picked 49 subjects to construct the model, whereas the remaining 11 subjects were utilized for validation. The results demonstrated that the model was a good regression compared to the observed values (Pearson's r=0.6, adjusted R square=0.4, p=9.4E-7, accuracy=49/60). Further analysis revealed that the average difference between the chronological age and predicted age was only 7.6±0.8years. It was concluded that this fast and non-invasive photon technology is sufficiently promising to be developed for the estimation of biological aging.

  16. Weak measurement and Bohmian conditional wave functions

    SciTech Connect

    Norsen, Travis; Struyve, Ward

    2014-11-15

    It was recently pointed out and demonstrated experimentally by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be “directly measured” using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a perhaps entangled multi-particle system, the result is precisely the so-called “conditional wave function” of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics uniquely makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-system’s density matrix should yield, under appropriate circumstances, the Bohmian “conditional density matrix” as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behavior–and also thereby reveal the non-local dependence of sub-system state functions on distant interventions–are suggested and discussed. - Highlights: • We study a “direct measurement” protocol for wave functions and density matrices. • Weakly measured states of entangled particles correspond to Bohmian conditional states. • Novel method of observing quantum non-locality is proposed.

  17. Skeletal muscle weakness in osteogeneis imperfecta mice

    PubMed Central

    Gentry, Bettina A; Ferreira, J. Andries; McCambridge, Amanda J.; Brown, Marybeth; Phillips, Charlotte L.

    2010-01-01

    Exercise intolerance, muscle fatigue and weakness are often-reported, little-investigated concerns of patients with osteogenesis imperfecta (OI). OI is a heritable connective tissue disorder hallmarked by bone fragility resulting primarily from dominant mutations in the proα1(I) or proα2(I) collagen genes and the recently discovered recessive mutations in post-translational modifying proteins of type I collagen. In this study we examined the soleus (S), plantaris (P), gastrocnemius (G), tibialis anterior (TA) and quadriceps (Q) muscles of mice expressing mild (+/oim) and moderately severe (oim/oim) OI for evidence of inherent muscle pathology. In particular, muscle weight, fiber cross-sectional area (CSA), fiber type, fiber histomorphology, fibrillar collagen content, absolute, relative and specific peak tetanic force (Po, Po/mg and Po/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased Po and an inability to sustain Po for the 300 ms testing duration for specific muscles; +/oim mice had a similar but milder skeletal muscle phenotype. +/oim mice had mild weakness of specific muscles but were less affected than their oim/oim counterparts which demonstrated readily apparent skeletal muscle pathology. Therefore muscle weakness in oim mice reflects inherent skeletal muscle pathology. PMID:20619344

  18. Weak homological dimensions and biflat Koethe algebras

    SciTech Connect

    Pirkovskii, A Yu

    2008-06-30

    The homological properties of metrizable Koethe algebras {lambda}(P) are studied. A criterion for an algebra A={lambda}(P) to be biflat in terms of the Koethe set P is obtained, which implies, in particular, that for such algebras the properties of being biprojective, biflat, and flat on the left are equivalent to the surjectivity of the multiplication operator A otimes-hat A{yields}A. The weak homological dimensions (the weak global dimension w.dg and the weak bidimension w.db) of biflat Koethe algebras are calculated. Namely, it is shown that the conditions w.db {lambda}(P)<=1 and w.dg {lambda}(P)<=1 are equivalent to the nuclearity of {lambda}(P); and if {lambda}(P) is non-nuclear, then w.dg {lambda}(P)=w.db {lambda}(P)=2. It is established that the nuclearity of a biflat Koethe algebra {lambda}(P), under certain additional conditions on the Koethe set P, implies the stronger estimate db {lambda}(P), where db is the (projective) bidimension. On the other hand, an example is constructed of a nuclear biflat Koethe algebra {lambda}(P) such that db {lambda}(P)=2 (while w.db {lambda}(P)=1). Finally, it is shown that many biflat Koethe algebras, while not being amenable, have trivial Hochschild homology groups in positive degrees (with arbitrary coefficients). Bibliography: 37 titles.

  19. Francium Spectroscopy for Weak Interaction Studies

    NASA Astrophysics Data System (ADS)

    Orozco, Luis

    2014-05-01

    Francium, a radioactive element, is the heaviest alkali. Its atomic and nuclear structure makes it an ideal laboratory to study the weak interaction. Laser trapping and cooling in-line with the superconducting LINAC accelerator at Stony Brook opened the precision study of its atomic structure. I will present our proposal and progress towards weak interaction measurements at TRIUMF, the National Canadian Accelerator in Vancouver. These include the commissioning run of the Francium Trapping Facility, hyperfine anomaly measurements on a chain of Fr isotopes, the nuclear anapole moment through parity non-conserving transitions in the ground state hyperfine manifold. These measurements should shed light on the nucleon-nucleon weak interaction. This work is done by the FrPNC collaboration: S. Aubin College of William and Mary, J. A. Behr TRIUMF, R. Collister U. Manitoba, E. Gomez UASLP, G. Gwinner U. Manitoba, M. R. Pearson TRIUMF, L. A. Orozco UMD, M. Tandecki TRIUMF, J. Zhang UMD Supported by NSF and DOE from the USA; TRIUMF, NRC and NSERC from Canada; and CONACYT from Mexico

  20. Age-related weakness of proximal muscle studied with motor cortical mapping: a TMS study.

    PubMed

    Plow, Ela B; Varnerin, Nicole; Cunningham, David A; Janini, Daniel; Bonnett, Corin; Wyant, Alexandria; Hou, Juliet; Siemionow, Vlodek; Wang, Xiao-Feng; Machado, Andre G; Yue, Guang H

    2014-01-01

    Aging-related weakness is due in part to degeneration within the central nervous system. However, it is unknown how changes to the representation of corticospinal output in the primary motor cortex (M1) relate to such weakness. Transcranial magnetic stimulation (TMS) is a noninvasive method of cortical stimulation that can map representation of corticospinal output devoted to a muscle. Using TMS, we examined age-related alterations in maps devoted to biceps brachii muscle to determine whether they predicted its age-induced weakness. Forty-seven right-handed subjects participated: 20 young (22.6 ± 0.90 years) and 27 old (74.96 ± 1.35 years). We measured strength as force of elbow flexion and electromyographic activation of biceps brachii during maximum voluntary contraction. Mapping variables included: 1) center of gravity or weighted mean location of corticospinal output, 2) size of map, 3) volume or excitation of corticospinal output, and 4) response density or corticospinal excitation per unit area. Center of gravity was more anterior in old than in young (p<0.001), though there was no significant difference in strength between the age groups. Map size, volume, and response density showed no significant difference between groups. Regardless of age, center of gravity significantly predicted strength (β = -0.34, p = 0.005), while volume adjacent to the core of map predicted voluntary activation of biceps (β = 0.32, p = 0.008). Overall, the anterior shift of the map in older adults may reflect an adaptive change that allowed for the maintenance of strength. Laterally located center of gravity and higher excitation in the region adjacent to the core in weaker individuals could reflect compensatory recruitment of synergistic muscles. Thus, our study substantiates the role of M1 in adapting to aging-related weakness and subtending strength and muscle activation across age groups. Mapping from M1 may offer foundation for an examination of mechanisms that preserve

  1. Oscillator strengths and collision strengths for S v

    NASA Technical Reports Server (NTRS)

    Van Wyngaarden, W. L.; Henry, R. J. W.

    1981-01-01

    Observations of the optical extreme-ultraviolet spectrum of the Jupiter planetary system during the Voyager space mission revealed bright emission lines of some sulfur ions. The spectra of the torus at the orbit of Io are likely to contain S V lines. The described investigation provides oscillator strengths and collision strengths for the first four UV lines. The collision strengths from the ground state to four other excited states are also obtained. Use is made of a two-state calculation which is checked for convergence for some transitions by employing a three-state or a four-state approximation. Target wave functions for S V are calculated so that the oscillator strengths calculated in dipole length and dipole velocity approximations agree within 5%.

  2. The role of weak hydrogen bonds in chiral recognition.

    PubMed

    Scuderi, Debora; Le Barbu-Debus, Katia; Zehnacker, A

    2011-10-28

    Chiral recognition has been studied in neutral or ionic weakly bound complexes isolated in the gas phase by combining laser spectroscopy and quantum chemical calculations. Neutral complexes of the two enantiomers of lactic ester derivatives with chiral chromophores have been formed in a supersonic expansion. Their structure has been elucidated by means of IR-UV double resonance spectroscopy in the 3 μm region. In both systems described here, the main interaction ensuring the cohesion of the complex is a strong hydrogen bond between the chromophore and methyl-lactate. However, an additional hydrogen bond of much weaker strength plays a discriminative role between the two enantiomers. For example, the 1:1 heterochiral complex between R-(+)-2-naphthyl-ethanol and S-(+) methyl-lactate is observed, in contrast with the 1:1 homochiral complex which lacks this additional hydrogen bond. On the other hand, the same kind of insertion structures is formed for the complex between S-(±)-cis-1-amino-indan-2-ol and the two enantiomers of methyl-lactate, but an additional addition complex is formed for R-methyl-lactate only. This selectivity rests on the formation of a weak CHπ interaction which is not possible for the other enantiomer. The protonated dimers of Cinchona alkaloids, namely quinine, quinidine, cinchonine and cinchonidine, have been isolated in an ion trap and studied by IRMPD spectroscopy in the region of the ν(OH) and ν(NH) stretch modes. The protonation site is located on the alkaloid nitrogen which acts as a strong hydrogen bond donor in all the dimers studied. While the nature of the intermolecular hydrogen bond is similar in the homochiral and heterochiral complexes, the heterochiral complex displays an additional weak CHO hydrogen bond located on its neutral part, which results in slightly different spectroscopic fingerprints in the ν(OH) stretch region. This first spectroscopic evidence of chiral recognition in protonated dimers opens the way to the

  3. Strength Measurements in Acute Hamstring Injuries: Intertester Reliability and Prognostic Value of Handheld Dynamometry.

    PubMed

    Reurink, Gustaaf; Goudswaard, Gert Jan; Moen, Maarten H; Tol, Johannes L; Verhaar, Jan A N; Weir, Adam

    2016-08-01

    Study Design Cohort study, repeated measures. Background Although hamstring strength measurements are used for assessing prognosis and monitoring recovery after hamstring injury, their actual clinical relevance has not been established. Handheld dynamometry (HHD) is a commonly used method of measuring muscle strength. The reliability of HHD has not been determined in athletes with acute hamstring injuries. Objectives To determine the intertester reliability and the prognostic value of hamstring HHD strength measurement in acute hamstring injuries. Methods We measured knee flexion strength with HHD in 75 athletes at 2 visits, at baseline (within 5 days of hamstring injury) and follow-up (5 to 7 days after the baseline measurement). We assessed isometric hamstring strength in 15° and 90° of knee flexion. Reliability analysis testing was performed by 2 testers independently at the follow-up visit. We recorded the time needed to return to play (RTP) up to 6 months following baseline. Results The intraclass correlation coefficients of the strength measurements in injured hamstrings were between 0.75 and 0.83. There was a statistically significant but weak correlation between the time to RTP and the strength deficit at 15° of knee flexion measured at baseline (Spearman r = 0.25, P = .045) and at the follow-up visit (Spearman r = 0.26, P = .034). Up to 7% of the variance in time to RTP is explained by this strength deficit. None of the other strength variables were significantly correlated with time to RTP. Conclusion Hamstring strength can be reliably measured with HHD in athletes with acute hamstring injuries. The prognostic value of strength measurements is limited, as there is only a weak association between the time to RTP and hamstring strength deficit after acute injury. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2016;46(8):689-696. Epub 12 May 2016. doi:10.2519/jospt.2016.6363.

  4. Standard systems for measurement of pKs and ionic mobilities. 1. Univalent weak acids.

    PubMed

    Slampová, Andrea; Krivánková, Ludmila; Gebauer, Petr; Bocek, Petr

    2008-12-01

    Determination of pK values of weak bases and acids by CZE has already attracted big attention in current practice and proved to offer the advantage of being applicable for mixtures of analytes. The method is based on the measurement of mobility curves plotting the effective mobility vs. the pH of the background electrolyte, and following computer-assisted regression involving corrections for ionic strength and temperature. To cover the necessary range of pH for a given case, both buffering weak acids and bases are used in one set of measurements, which requires implementing computations of individual ionic strength corrections for each pH value. It is also well known that some components of frequently used background electrolytes may interact with the analytes measured, on forming associates or complexes. This obviously deteriorates the reliability of the resulting data. This contribution brings a rational approach to this problem and establishes a standard system of anionic buffers for measurements of pKs and mobilities of weak acids, where the only counter cation present (besides H(+)) is Na(+). In this way, the risk of formation of complexes or associates of analytes with counter ions is strongly reduced. Moreover, the standard system of anionic buffers is selected in such a way that it provides, for an entire set of measurements, constant and accurately known ionic strength and the operational conditions are selected so that they provide constant Joule heating. Due to these precautions only one correction for ionic strength and temperature is needed for the obtained set of experimental data. This considerably facilitates their evaluation and regression analysis as the corrections need not be implemented in the computation software. The reliability and the advantages of the proposed system are well documented by experiments, where the known problematic group of phenol derivatives was measured with high accuracy and without any notice of anomalous behaviour. PMID

  5. Measurement of muscle strength in the intensive care unit.

    PubMed

    Bittner, Edward A; Martyn, Jeevendra A; George, Edward; Frontera, Walter R; Eikermann, Matthias

    2009-10-01

    Traditional (indirect) techniques, such as electromyography and nerve conduction velocity measurement, do not reliably predict intensive care unit-acquired muscle weakness and its clinical consequences. Therefore, quantitative assessment of skeletal muscle force is important for diagnosis of intensive care unit-acquired motor dysfunction. There are a number of ways for assessing objectively muscle strength, which can be categorized as techniques that quantify maximum voluntary contraction force and those that assess evoked (stimulated) muscle force. Important factors that limit the repetitive evaluation of maximum voluntary contraction force in intensive care unit patients are learning effects, pain during muscular contraction, and alteration of consciousness.The selection of the appropriate muscle is crucial for making adequate predictions of a patient's outcome. The upper airway dilators are much more susceptible to a decrease in muscle strength than the diaphragm, and impairment of upper airway patency is a key mechanism of extubation failure in intensive care unit patients. Data suggest that the adductor pollicis muscle is an appropriate reference muscle to predict weakness of muscles that are typically affected by intensive care unit-acquired weakness, i.e., upper airway as well as extremity muscles. Stimulated (evoked) force of skeletal muscles, such as the adductor pollicis, can be assessed repetitively, independent of brain function, even in heavily sedated patients during high acuity of their disease. PMID:20046117

  6. The Tensile Behavior of High-Strength Carbon Fibers.

    PubMed

    Langston, Tye

    2016-08-01

    Carbon fibers exhibit exceptional properties such as high stiffness and specific strength, making them excellent reinforcements for composite materials. However, it is difficult to directly measure their tensile properties and estimates are often obtained by tensioning fiber bundles or composites. While these macro scale tests are informative for composite design, their results differ from that of direct testing of individual fibers. Furthermore, carbon filament strength also depends on other variables, including the test length, actual fiber diameter, and material flaw distribution. Single fiber tensile testing was performed on high-strength carbon fibers to determine the load and strain at failure. Scanning electron microscopy was also conducted to evaluate the fiber surface morphology and precisely measure each fiber's diameter. Fiber strength was found to depend on the test gage length and in an effort to better understand the overall expected performance of these fibers at various lengths, statistical weak link scaling was performed. In addition, the true Young's modulus was also determined by taking the system compliance into account. It was found that all properties (tensile strength, strain to failure, and Young's modulus) matched very well with the manufacturers' reported values at 20 mm gage lengths, but deviated significantly at other lengths.

  7. The Tensile Behavior of High-Strength Carbon Fibers.

    PubMed

    Langston, Tye

    2016-08-01

    Carbon fibers exhibit exceptional properties such as high stiffness and specific strength, making them excellent reinforcements for composite materials. However, it is difficult to directly measure their tensile properties and estimates are often obtained by tensioning fiber bundles or composites. While these macro scale tests are informative for composite design, their results differ from that of direct testing of individual fibers. Furthermore, carbon filament strength also depends on other variables, including the test length, actual fiber diameter, and material flaw distribution. Single fiber tensile testing was performed on high-strength carbon fibers to determine the load and strain at failure. Scanning electron microscopy was also conducted to evaluate the fiber surface morphology and precisely measure each fiber's diameter. Fiber strength was found to depend on the test gage length and in an effort to better understand the overall expected performance of these fibers at various lengths, statistical weak link scaling was performed. In addition, the true Young's modulus was also determined by taking the system compliance into account. It was found that all properties (tensile strength, strain to failure, and Young's modulus) matched very well with the manufacturers' reported values at 20 mm gage lengths, but deviated significantly at other lengths. PMID:27278219

  8. Modeling variation in interaction strength between barnacles and fucoids.

    PubMed

    Kordas, Rebecca L; Dudgeon, Steve

    2009-01-01

    The strength by which species interact can vary throughout their ontogeny, as environments vary in space and time, and with the density of their populations. Characterizing strengths of interaction in situ for even a small number of species is logistically difficult and may apply only to those conditions under which the estimates were derived. We sought to combine data from field experiments estimating interaction strength of life stages of the barnacle, Semibalanus balanoides, on germlings of Ascophyllum nodosum, with a model that explored the consequences of variability at per capita and per population levels to the abundance of year-old algal recruits. We further simulated how this interaction affected fucoid germling abundance as the timing of their respective settlements varied relative to one another, as occurs regionally across the Gulf of Maine, USA. Juvenile S. balanoides have a weak estimated per capita effect on germlings. Germling populations are sensitive to variation in per capita effects of juvenile barnacles because of the typically large population sizes of the latter. However, high mortality of juvenile barnacles weakens the population interaction strength over time. Adult barnacles probably weakly facilitate fucoid germlings, but greater survival of adults sustains the strength of that interaction at the population level. Germling abundance is positively associated with densities of adult barnacles and negatively associated with that of juvenile barnacles. Metamorphosing cyprid larvae have the strongest per capita effect on germling abundance, but the interaction between the two stages is so short-lived that germling abundance is altered little. Variation in the timing of barnacle and A. nodosum settlement relative to one another had very little influence on the abundance of yearling germlings. Interactions between barnacles and germlings may influence the demographic structure of A. nodosum populations and the persistence of fucoid

  9. Modeling variation in interaction strength between barnacles and fucoids

    PubMed Central

    Dudgeon, Steve

    2009-01-01

    The strength by which species interact can vary throughout their ontogeny, as environments vary in space and time, and with the density of their populations. Characterizing strengths of interaction in situ for even a small number of species is logistically difficult and may apply only to those conditions under which the estimates were derived. We sought to combine data from field experiments estimating interaction strength of life stages of the barnacle, Semibalanus balanoides, on germlings of Ascophyllum nodosum, with a model that explored the consequences of variability at per capita and per population levels to the abundance of year-old algal recruits. We further simulated how this interaction affected fucoid germling abundance as the timing of their respective settlements varied relative to one another, as occurs regionally across the Gulf of Maine, USA. Juvenile S. balanoides have a weak estimated per capita effect on germlings. Germling populations are sensitive to variation in per capita effects of juvenile barnacles because of the typically large population sizes of the latter. However, high mortality of juvenile barnacles weakens the population interaction strength over time. Adult barnacles probably weakly facilitate fucoid germlings, but greater survival of adults sustains the strength of that interaction at the population level. Germling abundance is positively associated with densities of adult barnacles and negatively associated with that of juvenile barnacles. Metamorphosing cyprid larvae have the strongest per capita effect on germling abundance, but the interaction between the two stages is so short-lived that germling abundance is altered little. Variation in the timing of barnacle and A. nodosum settlement relative to one another had very little influence on the abundance of yearling germlings. Interactions between barnacles and germlings may influence the demographic structure of A. nodosum populations and the persistence of fucoid

  10. Compressive strength of carbon fibers

    SciTech Connect

    Prandy, J.M. ); Hahn, H.T. )

    1991-01-01

    Most composites are weaker in compression than in tension, which is due to the poor compressive strength of the load bearing fibers. The present paper discusses the compressive strengths and failure modes of 11 different carbon fibers: PAN-AS1, AS4, IM6, IM7, T700, T300, GY-30, pitch-75, ultra high modulus (UHM), high modulus (HM), and high strength (HS). The compressive strength was determined by embedding a fiber bundle in a transparent epoxy matrix and testing in compression. The resin allows for the containment and observation of failure during and after testing while also providing lateral support to the fibers. Scanning electron microscopy (SEM) was used to determine the global failure modes of the fibers.

  11. Lossy compression of weak lensing data

    SciTech Connect

    Vanderveld, R. Ali; Bernstein, Gary M.; Stoughton, Chris; Rhodes, Jason; Massey, Richard; Dobke, Benjamin M.

    2011-07-12

    Future orbiting observatories will survey large areas of sky in order to constrain the physics of dark matter and dark energy using weak gravitational lensing and other methods. Lossy compression of the resultant data will improve the cost and feasibility of transmitting the images through the space communication network. We evaluate the consequences of the lossy compression algorithm of Bernstein et al. (2010) for the high-precision measurement of weak-lensing galaxy ellipticities. This square-root algorithm compresses each pixel independently, and the information discarded is by construction less than the Poisson error from photon shot noise. For simulated space-based images (without cosmic rays) digitized to the typical 16 bits per pixel, application of the lossy compression followed by image-wise lossless compression yields images with only 2.4 bits per pixel, a factor of 6.7 compression. We demonstrate that this compression introduces no bias in the sky background. The compression introduces a small amount of additional digitization noise to the images, and we demonstrate a corresponding small increase in ellipticity measurement noise. The ellipticity measurement method is biased by the addition of noise, so the additional digitization noise is expected to induce a multiplicative bias on the galaxies measured ellipticities. After correcting for this known noise-induced bias, we find a residual multiplicative ellipticity bias of m {approx} -4 x 10-4. This bias is small when compared to the many other issues that precision weak lensing surveys must confront, and furthermore we expect it to be reduced further with better calibration of ellipticity measurement methods.

  12. Lossy compression of weak lensing data

    DOE PAGES

    Vanderveld, R. Ali; Bernstein, Gary M.; Stoughton, Chris; Rhodes, Jason; Massey, Richard; Dobke, Benjamin M.

    2011-07-12

    Future orbiting observatories will survey large areas of sky in order to constrain the physics of dark matter and dark energy using weak gravitational lensing and other methods. Lossy compression of the resultant data will improve the cost and feasibility of transmitting the images through the space communication network. We evaluate the consequences of the lossy compression algorithm of Bernstein et al. (2010) for the high-precision measurement of weak-lensing galaxy ellipticities. This square-root algorithm compresses each pixel independently, and the information discarded is by construction less than the Poisson error from photon shot noise. For simulated space-based images (without cosmicmore » rays) digitized to the typical 16 bits per pixel, application of the lossy compression followed by image-wise lossless compression yields images with only 2.4 bits per pixel, a factor of 6.7 compression. We demonstrate that this compression introduces no bias in the sky background. The compression introduces a small amount of additional digitization noise to the images, and we demonstrate a corresponding small increase in ellipticity measurement noise. The ellipticity measurement method is biased by the addition of noise, so the additional digitization noise is expected to induce a multiplicative bias on the galaxies measured ellipticities. After correcting for this known noise-induced bias, we find a residual multiplicative ellipticity bias of m {approx} -4 x 10-4. This bias is small when compared to the many other issues that precision weak lensing surveys must confront, and furthermore we expect it to be reduced further with better calibration of ellipticity measurement methods.« less

  13. Spurious Shear in Weak Lensing with LSST

    SciTech Connect

    Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.

    2012-09-19

    The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

  14. Nanoelectromechanics of superconducting weak links (Review Article)

    NASA Astrophysics Data System (ADS)

    Parafilo, A. V.; Krive, I. V.; Shekhter, R. I.; Jonson, M.

    2012-04-01

    Nanoelectromechanical effects in superconducting weak links are considered. Three different superconducting devices are studied: (i) a single-Cooper-pair transistor, (ii) a transparent SNS junction, and (iii) a single-level quantum dot coupled to superconducting electrodes. The electromechanical coupling is due to electrostatic or magnetomotive forces acting on a movable part of the device. It is demonstrated that depending on the frequency of mechanical vibrations the electromechanical coupling could either suppress or enhance the Josephson current. Nonequilibrium effects associated with cooling of the vibrational subsystem or pumping energy into it at low bias voltages are discussed.

  15. Thermodynamics of Weakly Measured Quantum Systems.

    PubMed

    Alonso, Jose Joaquin; Lutz, Eric; Romito, Alessandro

    2016-02-26

    We consider continuously monitored quantum systems and introduce definitions of work and heat along individual quantum trajectories that are valid for coherent superposition of energy eigenstates. We use these quantities to extend the first and second laws of stochastic thermodynamics to the quantum domain. We illustrate our results with the case of a weakly measured driven two-level system and show how to distinguish between quantum work and heat contributions. We finally employ quantum feedback control to suppress detector backaction and determine the work statistics. PMID:26967399

  16. Thermodynamics of Weakly Measured Quantum Systems

    NASA Astrophysics Data System (ADS)

    Alonso, Jose Joaquin; Lutz, Eric; Romito, Alessandro

    2016-02-01

    We consider continuously monitored quantum systems and introduce definitions of work and heat along individual quantum trajectories that are valid for coherent superposition of energy eigenstates. We use these quantities to extend the first and second laws of stochastic thermodynamics to the quantum domain. We illustrate our results with the case of a weakly measured driven two-level system and show how to distinguish between quantum work and heat contributions. We finally employ quantum feedback control to suppress detector backaction and determine the work statistics.

  17. Weak η production off the nucleon

    SciTech Connect

    Alam, M. Rafi; Athar, M. Sajjad; Alvarez-Ruso, L.; Vacas, M. J. Vicente

    2015-05-15

    The weak η-meson production off the nucleon induced by (anti)neutrinos is studied at low and intermediate energies, the range of interest for several ongoing and future neutrino experiments. We consider Born diagrams and the excitation of N{sup *} (1535)S{sub 11} and N{sup *} (1650)S{sub 11} resonances. The vector part of the N-S{sub 11} transition form factors has been obtained from the MAID helicity amplitudes while the poorly known axial part is constrained with the help of the partial conservation of the axial current (PCAC) and assuming the pion-pole dominance of the pseudoscalar form factor.

  18. Electrostatic decay in a weakly magnetized plasma.

    PubMed

    Layden, A; Cairns, Iver H; Li, B; Robinson, P A

    2013-05-01

    The kinematics of the electrostatic (ES) decay of a Langmuir wave into a Langmuir wave and an ion sound wave are generalized to a weakly magnetized plasma. Unlike the unmagnetized case, ES decay in a magnetized plasma is always kinematically permitted and can produce daughter Langmuir waves with very small wave numbers, which we demonstrate by quasilinear simulations. The simulations further show that ES decay in magnetized plasmas is consistent with STEREO spacecraft observations of transversely polarized Langmuir waves in the solar wind. PMID:23683206

  19. Supersymmetric Higgs Bosons in Weak Boson Fusion

    SciTech Connect

    Hollik, Wolfgang; Plehn, Tilman; Rauch, Michael; Rzehak, Heidi

    2009-03-06

    We compute the complete supersymmetric next-to-leading-order corrections to the production of a light Higgs boson in weak-boson fusion. The size of the electroweak corrections is of similar order as the next-to-leading-order corrections in the standard model. The supersymmetric QCD corrections turn out to be significantly smaller than expected and than their electroweak counterparts. These corrections are an important ingredient to a precision analysis of the (supersymmetric) Higgs sector at the LHC, either as a known correction factor or as a contribution to the theory error.

  20. Thermodynamics of Weakly Measured Quantum Systems.

    PubMed

    Alonso, Jose Joaquin; Lutz, Eric; Romito, Alessandro

    2016-02-26

    We consider continuously monitored quantum systems and introduce definitions of work and heat along individual quantum trajectories that are valid for coherent superposition of energy eigenstates. We use these quantities to extend the first and second laws of stochastic thermodynamics to the quantum domain. We illustrate our results with the case of a weakly measured driven two-level system and show how to distinguish between quantum work and heat contributions. We finally employ quantum feedback control to suppress detector backaction and determine the work statistics.

  1. LensTools: Weak Lensing computing tools

    NASA Astrophysics Data System (ADS)

    Petri, A.

    2016-02-01

    LensTools implements a wide range of routines frequently used in Weak Gravitational Lensing, including tools for image analysis, statistical processing and numerical theory predictions. The package offers many useful features, including complete flexibility and easy customization of input/output formats; efficient measurements of power spectrum, PDF, Minkowski functionals and peak counts of convergence maps; survey masks; artificial noise generation engines; easy to compute parameter statistical inferences; ray tracing simulations; and many others. It requires standard numpy and scipy, and depending on tools used, may require Astropy (ascl:1304.002), emcee (ascl:1303.002), matplotlib, and mpi4py.

  2. Plasma Emission by Weak Turbulence Processes

    NASA Astrophysics Data System (ADS)

    Ziebell, L. F.; Yoon, P. H.; Gaelzer, R.; Pavan, J.

    2014-11-01

    The plasma emission is the radiation mechanism responsible for solar type II and type III radio bursts. The first theory of plasma emission was put forth in the 1950s, but the rigorous demonstration of the process based upon first principles had been lacking. The present Letter reports the first complete numerical solution of electromagnetic weak turbulence equations. It is shown that the fundamental emission is dominant and unless the beam speed is substantially higher than the electron thermal speed, the harmonic emission is not likely to be generated. The present findings may be useful for validating reduced models and for interpreting particle-in-cell simulations.

  3. Naturalness and the weak gravity conjecture.

    PubMed

    Cheung, Clifford; Remmen, Grant N

    2014-08-01

    The weak gravity conjecture (WGC) is an ultraviolet consistency condition asserting that an Abelian force requires a state of charge q and mass m with q>m/m_{Pl}. We generalize the WGC to product gauge groups and study its tension with the naturalness principle for a charged scalar coupled to gravity. Reconciling naturalness with the WGC either requires a Higgs phase or a low cutoff at Λ∼qm_{Pl}. If neither applies, one can construct simple models that forbid a natural electroweak scale and whose observation would rule out the naturalness principle.

  4. Improved Quantum Signature Scheme with Weak Arbitrator

    NASA Astrophysics Data System (ADS)

    Su, Qi; Li, Wen-Min

    2013-09-01

    In this paper, we find a man-in-the-middle attack on the quantum signature scheme with a weak arbitrator (Luo et al., Int. J. Theor. Phys., 51:2135, 2012). In that scheme, the authors proposed a quantum signature based on quantum one way function which contains both verifying the signer phase and verifying the signed message phase. However, after our analysis we will show that Eve can adopt different strategies in respective phases to forge the signature without being detected. Then we present an improved scheme to increase the security.

  5. Weak Localization in few layer Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Gillgren, Nathaniel; Shi, Yanmeng; Espiritu, Timothy; Watanabe, Kenji; Taniguchi, Takahashi; Lau, Chun Ning (Jeanie)

    Few-layer black phosphorus has recently attracted interest from the scientific community due to its high mobility, tunable band gap, and large anisotropy. Recent experiments have demonstrated that black phosphorus provides a promising candidate to explore the physics of 2D semiconductors. In this study we explore the magnetotransport of few-layer black phosphorus-boron nitride hetereostructure devices at low magnetic fields. Weak localization is observed at low temperatures. We extract the dephasing length and measure its dependence on temperature, carrier density and electric field.

  6. Hollow vortices in weakly compressible flows

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Vikas; Crowdy, Darren

    2015-11-01

    In a two-dimensional, inviscid and steady fluid flow, hollow vortices are bounded regions of constant pressure with non-zero circulation. It is known that for an infinite row of incompressible hollow vortices, analytical solutions for the flow field and the shape of the hollow vortex boundary can be obtained using conformal mapping methods. In this talk, we show how to derive analytical expressions for a weakly compressible hollow vortex row. This is done by introducing a new method based on the Imai-Lamla formula. We will also touch upon how to extend these results to a von-Karman street of hollow vortices.

  7. Parametric Amplification For Detecting Weak Optical Signals

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Chen, Chien; Chakravarthi, Prakash

    1996-01-01

    Optical-communication receivers of proposed type implement high-sensitivity scheme of optical parametric amplification followed by direct detection for reception of extremely weak signals. Incorporates both optical parametric amplification and direct detection into optimized design enhancing effective signal-to-noise ratios during reception in photon-starved (photon-counting) regime. Eliminates need for complexity of heterodyne detection scheme and partly overcomes limitations imposed on older direct-detection schemes by noise generated in receivers and by limits on quantum efficiencies of photodetectors.

  8. Weak neutral currents and collapse initiated supernova

    SciTech Connect

    Wilson, J.R.

    1993-03-19

    Since 1974 the neutrino processes mediated by neutral currents have been a part of supernova (SN) modeling calculations. In this report only present day SN calculations will be discussed. First I will give brief description of the SN computer model and an outline of the explosion process as depicted by that model. Then I will discuss the role weak neutral current (WNC) processes play in this explosion process. Finally, I will discus inelastic scattering of tau neutrinos by heavy elements in WNC or Earth as a mechanism for measuring the mass of tau neutrino.

  9. [The weakness of individual psychologic dream theory].

    PubMed

    Strunz, F

    1988-05-13

    This article undertakes a critical evaluation of Adlerian dream theory. The main weakness of the theory is found to be its lack of an inherent instance of truth that shows the dreamer the way to a better and more feasible life style. Contemporary Adlerians' treatment of the master's dream dogmas and their practical use in psychotherapy are described. There seems to be a convergence movement of today's practical application methods of the dream in all psychotherapeutic schools. Adlerian dream interpretation in the original sense intended by Adler is practised nowhere by psychotherapists today and seems largely antiquated.

  10. Precision frequency measurements with interferometric weak values

    NASA Astrophysics Data System (ADS)

    Starling, David J.; Dixon, P. Ben; Jordan, Andrew N.; Howell, John C.

    2010-12-01

    We demonstrate an experiment which utilizes a Sagnac interferometer to measure a change in optical frequency of 129 ± 7 kHz/Hz with only 2 mW of continuous-wave, single-mode input power. We describe the measurement of a weak value and show how even higher-frequency sensitivities may be obtained over a bandwidth of several nanometers. This technique has many possible applications, such as precision relative frequency measurements and laser locking without the use of atomic lines.

  11. Failure behavior and constitutive model of weakly consolidated soft rock.

    PubMed

    Wang, Wei-ming; Zhao, Zeng-hui; Wang, Yong-ji; Gao, Xin

    2013-01-01

    Mining areas in western China are mainly located in soft rock strata with poor bearing capacity. In order to make the deformation failure mechanism and strength behavior of weakly consolidated soft mudstone and coal rock hosted in Ili No. 4 mine of Xinjiang area clear, some uniaxial and triaxial compression tests were carried out according to the samples of rocks gathered in the studied area, respectively. Meanwhile, a damage constitutive model which considered the initial damage was established by introducing a damage variable and a correction coefficient. A linearization process method was introduced according to the characteristics of the fitting curve and experimental data. The results showed that samples under different moisture contents and confining pressures presented completely different failure mechanism. The given model could accurately describe the elastic and plastic yield characteristics as well as the strain softening behavior of collected samples at postpeak stage. Moreover, the model could precisely reflect the relationship between the elastic modulus and confining pressure at prepeak stage.

  12. Failure Behavior and Constitutive Model of Weakly Consolidated Soft Rock

    PubMed Central

    Wang, Wei-ming; Zhao, Zeng-hui; Wang, Yong-ji; Gao, Xin

    2013-01-01

    Mining areas in western China are mainly located in soft rock strata with poor bearing capacity. In order to make the deformation failure mechanism and strength behavior of weakly consolidated soft mudstone and coal rock hosted in Ili No. 4 mine of Xinjiang area clear, some uniaxial and triaxial compression tests were carried out according to the samples of rocks gathered in the studied area, respectively. Meanwhile, a damage constitutive model which considered the initial damage was established by introducing a damage variable and a correction coefficient. A linearization process method was introduced according to the characteristics of the fitting curve and experimental data. The results showed that samples under different moisture contents and confining pressures presented completely different failure mechanism. The given model could accurately describe the elastic and plastic yield characteristics as well as the strain softening behavior of collected samples at postpeak stage. Moreover, the model could precisely reflect the relationship between the elastic modulus and confining pressure at prepeak stage. PMID:24489511

  13. Pollux: a stable weak dipolar magnetic field but no planet?

    NASA Astrophysics Data System (ADS)

    Aurière, Michel; Konstantinova-Antova, Renada; Espagnet, Olivier; Petit, Pascal; Roudier, Thierry; Charbonnel, Corinne; Donati, Jean-François; Wade, Gregg A.

    2014-08-01

    Pollux is considered as an archetype of a giant star hosting a planet: its radial velocity (RV) presents sinusoidal variations with a period of about 590 d, which have been stable for more than 25 years. Using ESPaDOnS and Narval we have detected a weak (sub-gauss) magnetic field at the surface of Pollux and followed up its variations with Narval during 4.25 years, i.e. more than for two periods of the RV variations. The longitudinal magnetic field is found to vary with a sinusoidal behaviour with a period close to that of the RV variations and with a small shift in phase. We then performed a Zeeman Doppler imaging (ZDI) investigation from the Stokes V and Stokes I least-squares deconvolution (LSD) profiles. A rotational period is determined, which is consistent with the period of variations of the RV. The magnetic topology is found to be mainly poloidal and this component almost purely dipolar. The mean strength of the surface magnetic field is about 0.7 G. As an alternative to the scenario in which Pollux hosts a close-in exoplanet, we suggest that the magnetic dipole of Pollux can be associated with two temperature and macroturbulent velocity spots which could be sufficient to produce the RV variations. We finally investigate the scenarii of the origin of the magnetic field which could explain the observed properties of Pollux.

  14. Plasma waves downstream of weak collisionless shocks

    NASA Technical Reports Server (NTRS)

    Coroniti, F. V.; Greenstadt, E. W.; Moses, S. L.; Smith, E. J.; Tsurutani, B. T.

    1993-01-01

    In September 1983 the International Sun Earth Explorer 3 (ISEE 3) International Cometary Explorer (ICE) spacecraft made a long traversal of the distant dawnside flank region of the Earth's magnetosphere and had many encounters with the low Mach number bow shock. These weak shocks excite plasma wave electric field turbulence with amplitudes comparable to those detected in the much stronger bow shock near the nose region. Downstream of quasi-perpendicular (quasi-parallel) shocks, the E field spectra exhibit a strong peak (plateau) at midfrequencies (1 - 3 kHz); the plateau shape is produced by a low-frequency (100 - 300 Hz) emission which is more intense behind downstream of two quasi-perpendicular shocks show that the low frequency signals are polarized parallel to the magnetic field, whereas the midfrequency emissions are unpolarized or only weakly polarized. A new high frequency (10 - 30 kHz) emission which is above the maximum Doppler shift exhibit a distinct peak at high frequencies; this peak is often blurred by the large amplitude fluctuations of the midfrequency waves. The high-frequency component is strongly polarized along the magnetic field and varies independently of the lower-frequency waves.

  15. Probing hysteretic elasticity in weakly nonlinear materials

    SciTech Connect

    Johnson, Paul A; Haupert, Sylvain; Renaud, Guillaume; Riviere, Jacques; Talmant, Maryline; Laugier, Pascal

    2010-12-07

    Our work is aimed at assessing the elastic and dissipative hysteretic nonlinear parameters' repeatability (precision) using several classes of materials with weak, intermediate and high nonlinear properties. In this contribution, we describe an optimized Nonlinear Resonant Ultrasound Spectroscopy (NRUS) measuring and data processing protocol applied to small samples. The protocol is used to eliminate the effects of environmental condition changes that take place during an experiment, and that may mask the intrinsic elastic nonlinearity. As an example, in our experiments, we identified external temperature fluctuation as a primary source of material resonance frequency and elastic modulus variation. A variation of 0.1 C produced a frequency variation of 0.01 %, which is similar to the expected nonlinear frequency shift for weakly nonlinear materials. In order to eliminate environmental effects, the variation in f{sub 0} (the elastically linear resonance frequency proportional to modulus) is fit with the appropriate function, and that function is used to correct the NRUS calculation of nonlinear parameters. With our correction procedure, we measured relative resonant frequency shifts of 10{sup -5} , which are below 10{sup -4}, often considered the limit to NRUS sensitivity under common experimental conditions. Our results show that the procedure is an alternative to the stringent control of temperature often applied. Applying the approach, we report nonlinear parameters for several materials, some with very small nonclassical nonlinearity. The approach has broad application to NRUS and other Nonlinear Elastic Wave Spectroscopy approaches.

  16. Weak Decays of Excited B Mesons.

    PubMed

    Grinstein, B; Martin Camalich, J

    2016-04-01

    We investigate the decays of the excited (bq[over ¯]) mesons as probes of the short-distance structure of the weak ΔB=1 transitions. These states are unstable under the electromagnetic or strong interactions, although their widths are typically suppressed by phase space. Compared to the pseudoscalar B meson, the purely leptonic decays of the vector B^{*} are not chirally suppressed and are sensitive to different combinations of the underlying weak effective operators. An interesting example is B_{s}^{*}→ℓ^{+}ℓ^{-}, which has a rate that can be accurately predicted in the standard model. The branching fraction is B∼10^{-11}, irrespective of the lepton flavor and where the main uncertainty stems from the unmeasured and theoretically not well known B_{s}^{*} width. We discuss the prospects for producing this decay mode at the LHC and explore the possibility of measuring the B_{s}^{*}→ℓℓ amplitude, instead, through scattering experiments at the B_{s}^{*} resonance peak. PMID:27104698

  17. Auroral weak double layers: A critical assessment

    NASA Astrophysics Data System (ADS)

    Koskinen, Hannu E. J.; Mälkki, Anssi M.

    Weak double layers (WDLs) were first observed in the mid-altitude auroral magnetosphere in 1976 by the S3-3 satellite. The observations were confirmed by Viking in 1986, when more detailed information of these small-scale plasma structures became available. WDLs are upward moving rarefactive solitary structures with negative electric potential. The potential drop over a WDL is typically 0-1 V with electric field pointing predominantly upward. The structures are usually found in relatively weak (≤2 kV) auroral acceleration regions where the field-aligned current is upward, but sometimes very small. The observations suggest that WDLs exist in regions of cool electron and ion background. Most likely the potential structures are embedded in the background ion population that may drift slowly upward. There have been several attempts for plasma physical explanation of WDLs but so far the success has not been very good. Computer simulations have been able to produce similar structures, but usually for somewhat unrealistic plasma parameters. A satisfactory understanding of the phenomenon requires consideration of the role of WDLs in the magnetosphere-ionosphere (MI) coupling, including the large-scale electric fields, both parallel and perpendicular to the magnetic field, and the Alfvén waves mediating the coupling. In this report we give a critical review of our present understanding of WDLs. We try to find out what can be safely deduced from the observations, what are just educated guesses, and where we may go wrong.

  18. Weak scale from the maximum entropy principle

    NASA Astrophysics Data System (ADS)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2015-03-01

    The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.

  19. Weak Decays of Excited B Mesons.

    PubMed

    Grinstein, B; Martin Camalich, J

    2016-04-01

    We investigate the decays of the excited (bq[over ¯]) mesons as probes of the short-distance structure of the weak ΔB=1 transitions. These states are unstable under the electromagnetic or strong interactions, although their widths are typically suppressed by phase space. Compared to the pseudoscalar B meson, the purely leptonic decays of the vector B^{*} are not chirally suppressed and are sensitive to different combinations of the underlying weak effective operators. An interesting example is B_{s}^{*}→ℓ^{+}ℓ^{-}, which has a rate that can be accurately predicted in the standard model. The branching fraction is B∼10^{-11}, irrespective of the lepton flavor and where the main uncertainty stems from the unmeasured and theoretically not well known B_{s}^{*} width. We discuss the prospects for producing this decay mode at the LHC and explore the possibility of measuring the B_{s}^{*}→ℓℓ amplitude, instead, through scattering experiments at the B_{s}^{*} resonance peak.

  20. Oxygen consumption in weakly electric Neotropical fishes.

    PubMed

    Julian, David; Crampton, William G R; Wohlgemuth, Stephanie E; Albert, James S

    2003-12-01

    Weakly electric gymnotiform fishes with wave-type electric organ discharge (EOD) are less hypoxia-tolerant and are less likely to be found in hypoxic habitats than weakly electric gymnotiforms with pulse-type EOD, suggesting that differences in metabolism resulting from EOD type affects habitat choice. Although gymnotiform fishes are common in most Neotropical freshwaters and represent the dominant vertebrates in some habitats, the metabolic rates of these unique fishes have never been determined. In this study, O(2) consumption rates during EOD generation are reported for 34 gymnotiforms representing 23 species, all five families and 17 (59%) of the 28 genera. Over the size range sampled (0.4 g to 125 g), O(2) consumption of gymnotiform fishes was dependent on body mass, as expected, fitting a power function with a scaling exponent of 0.74, but the O(2) consumption rate was generally about 50% of that expected by extrapolation of temperate teleost metabolic rates to a similar ambient temperature (26 degrees C). O(2) consumption rate was not dependent on EOD type, but maintenance of "scan swimming" (continuous forwards and backwards swimming), which is characteristic only of gymnotiforms with wave-type EODs, increased O(2) consumption 2.83+/-0.49-fold (mean+/-SD). This suggests that the increased metabolic cost of scan swimming could restrict gymnotiforms with wave-type EODs from hypoxic habitats.