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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. Crossing Institutional Boundaries: Writing Strengths and Weaknesses.

    ERIC Educational Resources Information Center

    Lumpkins, Julie

    At any level, good writing requires an acknowledgment of writing strengths and weaknesses by both student and instructor. The four project collaborators/writing teachers outlined six specific areas on a teacher feedback sheet to note students' writing strengths and weaknesses; the areas of purpose, audience, thesis, development, organization, and…

  3. Weakness

    MedlinePlus

    Lack of strength; Muscle weakness ... feel weak but have no real loss of strength. This is called subjective weakness. It may be ... flu. Or, you may have a loss of strength that can be noted on a physical exam. ...

  4. 75 FR 79295 - New Animal Drugs; Mupirocin

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-20

    ... use of mupirocin ointment for the treatment of bacterial skin infections in dogs. DATES: This rule is... Mupirocin Ointment USP, 2% for the treatment of bacterial skin infections in dogs. Taro Pharmaceuticals...

  5. Cultural Capital: Strengths, Weaknesses and Two Advancements

    ERIC Educational Resources Information Center

    van de Werfhorst, Herman G.

    2010-01-01

    In this paper I discuss two weaknesses in Bourdieu's work on cultural capital, both of which are related to his integration of the multidimensional nature of social space in different domains of life: social mobility, lifestyle differentiation, and political orientation. First, there is an anomaly between the work on social mobility and on…

  6. 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

  7. 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…

  8. 21 CFR 524.1465 - Mupirocin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Mupirocin. 524.1465 Section 524.1465 Food and 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) Specifications. Each gram of ointment...

  9. [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. PMID:19593481

  10. Mupirocin

    MedlinePlus

    ... as well as other skin infections caused by bacteria. It is not effective against fungal or viral ... not swallow it. Do not apply dressings, bandages, cosmetics, lotions, or other skin medications to the area ...

  11. 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. PMID:26093888

  12. Strengths Weaknesses Opportunities and Threats of Blended Learning: Students’ Perceptions

    PubMed Central

    Hande, S

    2014-01-01

    Background: Blended learning (BL) in a cell biology course of the premedical program at the Kasturba Medical College International Centre, Manipal, India, commenced in 2006. The program provides training in basic sciences to students, especially from the United States and Canada. The approach to the study was phenomenographic, with a qualitative study design using an open-ended questionnaire, focused interviews and empirical observations. Aim: The aim of this study was to identify the strengths, weaknesses, opportunities and threats (SWOT) of BL in a premedical class. Subjects and Methods: It was a cross-sectional study. Ninety six students in a premedical cell biology class participated in the study. SWOT analysis of students’ perceptions was conducted manually. Statistical analysis included content analysis of qualitative data to classify data and aligning them into the SWOT analysis matrix. Results: The outcomes of the study revealed student perceptions in terms of SWOT of BL and the potential uses of this strategy. Conclusions: The study provides background for educators and curriculum experts to plan their modules while incorporating a BL approach. PMID:24971204

  13. Surveillance for mupirocin resistance following introduction of routine peri-operative prophylaxis with nasal mupirocin.

    PubMed

    Fawley, W N; Parnell, P; Hall, J; Wilcox, M H

    2006-03-01

    The authors have previously described the successful use of a five-day peri-operative prophylaxis regimen using nasal mupirocin and topical triclosan (PPNMTT) to prevent methicillin-resistant Staphylococcus aureus (MRSA) infection. The present article describes the results of repeated point-prevalence surveillance for four years to determine whether mupirocin resistance has emerged in surgical units using empirical, short-term, peri-operative prophylaxis with nasal mupirocin. Before starting PPNMTT and every six months thereafter for four years, point-prevalence surveillance was performed for nasal S. aureus carriage in all patients on five orthopaedic surgery wards, one vascular surgery ward and one elderly medicine control ward. S. aureus screening and clinical isolates (surgical patients) were undertaken for low- [minimum inhibitory concentration (MIC) 8-128 mg/L] and high-level (MIC > 128 mg/L) mupirocin resistance. All isolates were phage typed to determine whether there was evidence of the spread of clonal mupirocin-resistant strains. Of 593, 139 and 206 nasal screening swabs (taken after the regimen had started) from orthopaedic, vascular and control patients, 28%, 24% and 48% (orthopaedic/vascular surgery vs elderly medicine, P < 0.001) yielded S. aureus isolates, respectively, and 12%, 11% and 30% (P < 0.001) were MRSA positive, respectively. Of the S. aureus nasal screen isolates from orthopaedic/vascular surgery and control patients, 5% and 4%, respectively, were low-level mupirocin resistant (P > 0.1). Of 286 (orthopaedic/vascular surgery) and 68 (elderly medicine) clinical S. aureus isolates obtained after the regimen had started, 7% and 9% (P > 0.1), respectively, were low-level mupirocin resistant. No high-level mupirocin-resistant isolates were isolated from mupirocin (orthopaedic/vascular surgery) or elderly medicine control ward patients. There was no trend towards increasing prevalence of low-level mupirocin resistance during the four-year study

  14. 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…

  15. 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,…

  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. 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…

  18. 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…

  19. Models of Viscosity: Strengths, Weaknesses and the Challenges

    NASA Astrophysics Data System (ADS)

    Russell, K.; Giordano, D.; Dingwell, D. B.

    2007-12-01

    properties, and to work over a wider range of melt conditions (composition and temperature). Other models fail because they use a non-Arrhenian formulation, or they are calibrated for an extremely small range of melt conditions, or they predict unphysical values of viscosity in the limits, or they are over-parameterized and cannot be extrapolated beyond the original calibration dataset. Our model predicts, within inter-laboratory experimental error, viscosity and other melt properties (i.e., Tg amd m) for most of the T-X space found in natural silicate melts. Despite its strengths, there is room for improvement. Firstly, our model incorporates the effects of H2O and F, but does not account for other important volatiles, including CO2, S, Cl. Secondly, Fe is treated as a single species whereas melts contain variable proportions of ferric and ferrous iron. Thirdly, we do not model pressure effects on melt viscosity which is needed for modeling melt transport within the lithosphere. Lastly, our model is strictly empirical, in that, the components we have chosen have no explicit or independent relationship to the structure or speciation of the silicate melt. Future models may benefit from the use of a component basis that reflects melt speciation. Giordano, D. Russell, J.K. & Dingwell, D.B. (In Review, July 07) Viscosity of magmatic liquids: A model. EPSL

  20. 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…

  1. 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…

  2. The Strengths and Weaknesses of Total Quality Management in Higher Education.

    ERIC Educational Resources Information Center

    Hazzard, Terry

    This paper defines Total Quality Management (TQM), discusses its origins, and identifies its strengths and weaknesses as they apply to higher education. The paper defines TQM as a philosophy of organizations that defines quality and improves organizational performance and administrative systems. The system originated from statistical quality…

  3. Profiles of Strengths and Weaknesses in Dyslexia and Other Learning Difficulties

    ERIC Educational Resources Information Center

    Everatt, John; Weeks, Sally; Brooks, Peter

    2008-01-01

    A total of 83 children with different special educational needs (SEN) assessments were contrasted with a control group (N = 40) without special needs on measures that aimed to identify potential areas of strengths as well as weaknesses in these SEN groups. Carefully selected groups of dyslexics, dyspraxics, children with specific language…

  4. 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…

  5. Building a Performance-Based Assessment System To Diagnose Strengths and Weaknesses in Reading Achievement.

    ERIC Educational Resources Information Center

    Hennings, Sara S.; Hughes, Kay E.

    This paper provides a brief description of the development of the Diagnostic Assessments of Reading with Trial Teaching Strategies (DARTTS) program by F. G. Roswell and J. S. Chall. It also describes the editorial and statistical procedures that were used to validate the program for determining students' strengths and weaknesses in important areas…

  6. Strength and fatigue of zirconia-induced weak spots in optical fiber

    NASA Astrophysics Data System (ADS)

    Breuls, Anton H. E.; Svenson, T.

    1994-03-01

    The reliability of long lengths of fibers in optical cables is determined by the presence of weak spots which are infrequently produced by normal fiber production methods. It is important to investigate the influence on strength of fiber from different kinds of weak spots. The present study is confined to weak spots resulting from melted-in zirconia particles. Tensile testing of optical fiber, in which strength degrading particles of a roughly dual-size distribution have been introduced on purpose, was done At a wide range of stress rates. The Weibull plots of tensile strength of the fiber were compared with a theoretical distribution, based on a simple relation between particle size and fiber strength. In this way, failure modes could be identified and related to the size of particles. From the comparison it was concluded that the size of zirconia particles has no significant influence on the fatigue of fiber, within the applied stress rates. A significant retardment of the fatigue of weak spots was also observed at low stress rates.

  7. Strength trapped within weakness/ weakness trapped within strength: the influence of family of origin experiences on the lives of abused women.

    PubMed

    Buchbinder, Eli; Birnbaum, Liora

    2010-06-01

    By conceptualizing abused women as victims or survivors, the literature offers two contradictory narratives of abused women. The aim of this article is to show that these two narratives are not mutually exclusive but rather can be used simultaneously to represent battered women's existential experiences. The study sample was comprised of 20 Israeli battered women. Three in-depth interviews were conducted with each participant-twice for data collection purposes and once for validating the themes that emerged from the content analysis. "Strength trapped in weakness/weakness trapped in strength" was found to be a dominant theme in the life narratives of the interviewees. Most interviewees grew up in families of origin in distress; most were abused physically and emotionally. Although this anguish colored their lives with pain and turmoil, their experiences were the key to their ability to overcome difficulties. From the onset, interviewees' lives were marked by a sense of threat and deprivation, but these very difficulties were also the source of a sense of power that emerged from the women's struggle with their past. In their attempts to cope with and transcend the legacies of their past, interviewees' feelings oscillated continuously between past and present, creating a unique powerful sense of simultaneously being victims and survivors. Implications for intervention are suggested. PMID:20445077

  8. The power of the mind: the cortex as a critical determinant of muscle strength/weakness.

    PubMed

    Clark, Brian C; Mahato, Niladri K; Nakazawa, Masato; Law, Timothy D; Thomas, James S

    2014-12-15

    We tested the hypothesis that the nervous system, and the cortex in particular, is a critical determinant of muscle strength/weakness and that a high level of corticospinal inhibition is an important neurophysiological factor regulating force generation. A group of healthy individuals underwent 4 wk of wrist-hand immobilization to induce weakness. Another group also underwent 4 wk of immobilization, but they also performed mental imagery of strong muscle contractions 5 days/wk. Mental imagery has been shown to activate several cortical areas that are involved with actual motor behaviors, including premotor and M1 regions. A control group, who underwent no interventions, also participated in this study. Before, immediately after, and 1 wk following immobilization, we measured wrist flexor strength, voluntary activation (VA), and the cortical silent period (SP; a measure that reflect corticospinal inhibition quantified via transcranial magnetic stimulation). Immobilization decreased strength 45.1 ± 5.0%, impaired VA 23.2 ± 5.8%, and prolonged the SP 13.5 ± 2.6%. Mental imagery training, however, attenuated the loss of strength and VA by ∼50% (23.8 ± 5.6% and 12.9 ± 3.2% reductions, respectively) and eliminated prolongation of the SP (4.8 ± 2.8% reduction). Significant associations were observed between the changes in muscle strength and VA (r = 0.56) and SP (r = -0.39). These findings suggest neurological mechanisms, most likely at the cortical level, contribute significantly to disuse-induced weakness, and that regular activation of the cortical regions via imagery attenuates weakness and VA by maintaining normal levels of inhibition. PMID:25274345

  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. Profiles of strengths and weaknesses in dyslexia and other learning difficulties.

    PubMed

    Everatt, John; Weeks, Sally; Brooks, Peter

    2008-02-01

    A total of 83 children with different special educational needs (SEN) assessments were contrasted with a control group (N = 40) without special needs on measures that aimed to identify potential areas of strengths as well as weaknesses in these SEN groups. Carefully selected groups of dyslexics, dyspraxics, children with specific language difficulties, moderate learning disabilities, attention deficits and emotional/behavioural disorders were assessed on measures of literacy, phonological and verbal skills, non-verbal ability, problem behaviour scales and cognitive interference. Scores indicated that individual measures were relatively poor at specifically differentiating one SEN group from the controls and that all SEN groups presented evidence of literacy deficits despite potentially different causes for such acquisition difficulties. For most of the six SEN groups targeted, assessments that considered strengths as well as weaknesses provided a profile that specifically differentiated the group from the controls in contrast to the other SEN groups tested. PMID:17659648

  11. Targeting cancer’s weaknesses (not its strengths): Therapeutic strategies suggested by the atavistic model

    PubMed Central

    Lineweaver, Charles H.; Davies, Paul C.W.; Vincent, Mark D.

    2014-01-01

    In the atavistic model of cancer progression, tumor cell dedifferentiation is interpreted as a reversion to phylogenetically earlier capabilities. The more recently evolved capabilities are compromised first during cancer progression. This suggests a therapeutic strategy for targeting cancer: design challenges to cancer that can only be met by the recently evolved capabilities no longer functional in cancer cells. We describe several examples of this target-the-weakness strategy. Our most detailed example involves the immune system. The absence of adaptive immunity in immunosuppressed tumor environments is an irreversible weakness of cancer that can be exploited by creating a challenge that only the presence of adaptive immunity can meet. This leaves tumor cells more vulnerable than healthy tissue to pathogenic attack. Such a target-the-weakness therapeutic strategy has broad applications, and contrasts with current therapies that target the main strength of cancer: cell proliferation. PMID:25043755

  12. 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.

  13. 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. PMID:17970252

  14. Motivated Implicit Theories of Personality: My Weaknesses Will Go Away, but My Strengths Are Here to Stay.

    PubMed

    Steimer, Andreas; Mata, André

    2016-04-01

    Across six studies, this research found consistent evidence for motivated implicit theories about personality malleability: People perceive their weaknesses as more malleable than their strengths. Moreover, motivation also influences how people see themselves in the future, such that they expect their present strengths to remain constant, but they expect their present weaknesses to improve in the future. Several additional findings suggest the motivational nature of these effects: The difference in perceived malleability for strengths versus weaknesses was only observed for the self, not for other people. When the desirability of possessing a certain trait was manipulated, that trait was perceived to be more malleable when it was depicted as undesirable. And these different beliefs that people have about how malleable their traits are, and how they will develop in the future, were associated with their desire for change, which is higher for weaknesses versus strengths. PMID:26984009

  15. Pulse wave analysis and pulse wave velocity: a critical review of their strengths and weaknesses.

    PubMed

    Davies, Justine Ina; Struthers, Allan D

    2003-03-01

    The study of the pulse using the technique of applanation tonometry is undergoing a resurgence with the development of new computerized equipment. We aim here to present a critical review of the uses, potential uses, strengths and weaknesses of the technique of applanation tonometry for the assessment of augmentation index and pulse wave velocity. We will review the technique of applanation tonometry, the physiological factors affecting pulse wave velocity and pulse wave analysis, the changes in pulse wave velocity and pulse wave analysis with pharmacological interventions, and the use of the technique of applanation tonometry as a prognostic tool. We conclude that, although the technique of applanation tonometry initially seems promising, several pertinent issues need to be addressed before it can be used reliably as a clinical or research tool. Importantly, use of the technique of applanation tonometry to derive the central waveform from non-invasively acquired peripheral data needs to be validated prospectively. PMID:12640232

  16. Appreciating the Strengths and Weaknesses of Transthoracic Echocardiography in Hemodynamic Assessments

    PubMed Central

    Huang, Stephen J.; McLean, Anthony S.

    2012-01-01

    Transthoracic echocardiography (TTE) is becoming the choice of hemodynamic assessment tool in many intensive care units. With an ever increasing number of training programs available worldwide, learning the skills to perform TTE is no longer a limiting factor. Instead, the future emphasis will be shifted to teach the users how to recognize measurement errors and artefacts (internal validity), to realize the limitations of TTE in various applications, and finally how to apply the information to the patient in question (external validity). This paper aims to achieve these objectives in a common area of TTE application—hemodynamic assessments. We explore the strengths and weaknesses of TTE in such assessments in this paper. Various methods of hemodynamic assessments, such as cardiac output measurements, estimation of preload, and assessment of fluid responsiveness, will be discussed. PMID:22454777

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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. PMID:26772124

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  9. A Study to Identify Areas of Relative Strength and Weakness in Support for the Saint Leo College Library Acquisitions Project.

    ERIC Educational Resources Information Center

    McLeod, Stephen G.

    The practicum sought to identify areas of relative strength and weakness in support for the Saint Leo College (Florida) Library Acquisitions Project, a project to improve library support to the Military Education Program administered by Saint Leo College on military installations throughout the Southeast. Using the Interactive Forces Theory of…

  10. Cavities of Weak Magnetic Field Strength in the Wake of FTEs: Results from Global Magnetospheric MHD Simulations

    NASA Technical Reports Server (NTRS)

    Kuznetsova, M. M.; Sibeck, D. G.; Hesse, M.; Wang, Y.; Rastaetter, L.; Toth, G.; Ridley, A.

    2009-01-01

    We use the global magnetohydrodynamic (MHD) code BATS-R-US to model multipoint observations of Flux Transfer Event (FTE) signatures. Simulations with high spatial and temporal resolution predict that cavities of weak magnetic field strength protruding into the magnetosphere trail FTEs. These predictions are consistent with recently reported multi-point Cluster observations of traveling magnetopause erosion regions (TMERs).

  11. 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…

  12. In the students' own words: what are the strengths and weaknesses of the dental school curriculum?

    PubMed

    Henzi, David; Davis, Elaine; Jasinevicius, Roma; Hendricson, William

    2007-05-01

    Dental students have little input into the selection of course topics and subject matter included in their dental curricula. Curriculum requirements are framed by the Commission on Dental Accreditation, which has stipulated competencies and associated biomedical and clinical knowledge that must be addressed during dental school. Although these competency requirements restrict the variance of educational experiences, students are eager to share their views on the curriculum within the realm of their educational experience. The objective of this research project was to elicit the perspectives of dental students from a broad cross-section of U.S. and Canadian dental schools about their education. A total of 605 students (285 sophomores, 220 seniors, 100 residents) from twenty North American dental schools completed a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis to communicate their perceptions of the curriculum. Students were also asked to provide their impressions of the overall quality of the educational program in an open-ended written format. The students' qualitative comments were then reviewed and categorized into key issues or themes. Resulting themes for each category of the Curriculum SWOT (C-SWOT) analysis were the following. Strengths: 1) clinical learning experience, and 2) opportunity to work with knowledgeable faculty. Weaknesses: 1) disorganized and inefficient clinical learning environment, 2) teaching and testing that focus on memorization, 3) poor quality instruction characterized by curricular disorganization, and 4) inconsistency among instructors during student evaluations. Opportunities: 1) develop strategies to provide students with more exposure to patients, especially early in the curriculum, and 2) opportunities to learn new technology/techniques. Threats: 1) cost of dental education, 2) students' concerns about faculty "brain drain," i.e., lack of sufficient numbers of dental faculty capable of providing high

  13. Macroeconomics of Natural Disasters: Strengths and Weaknesses of Meta-Analysis Versus Review of Literature.

    PubMed

    A G van Bergeijk, Peter; Lazzaroni, Sara

    2015-06-01

    We use the case of the macroeconomic impact of natural disasters to analyze strengths and weaknesses of meta-analysis in an emerging research field. Macroeconomists have published on this issue since 2002 (we identified 60 studies to date). The results of the studies are contradictory and therefore the need to synthesize the available research is evident. Meta-analysis is a useful method in this field. An important aim of our article is to show how one can use the identified methodological characteristics to better understand the robustness and importance of new findings. To provide a comparative perspective, we contrast our meta-analysis and its findings with the major influential research synthesis in the field: the IPCC's 2012 special report Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. We show that the IPCC could have been more confident about the negative economic impact of disasters and more transparent on inclusion and qualification of studies, if it had been complemented by a meta-analysis. Our meta-analysis shows that, controlling for modeling strategies and data set, the impact of disasters is significantly negative. The evidence is strongest for direct costs studies where we see no difference between our larger sample and the studies included in the IPCC report. Direct cost studies and indirect cost studies differ significantly, both in terms of the confidence that can be attached to a negative impact of natural disasters and in terms of the sources of heterogeneity of the findings reported in the primary studies. PMID:25847486

  14. Strength of chrysotile-serpentinite gouge under hydrothermal conditions: Can it explain a weak San Andreas fault?

    USGS Publications Warehouse

    Moore, Diane E.; Lockner, D.A.; Summers, R.; Shengli, M.; Byerlee, J.D.

    1996-01-01

    Chrysotile-bearing serpentinite is a constituent of the San Andreas fault zone in central and northern California. At room temperature, chrysotile gouge has a very low coefficient of friction (?? ??? 0.2), raising the possibility that under hydrothermal conditions ?? might be reduced sufficiently (to ???0.1) to explain the apparent weakness of the fault. To test this hypothesis, we measured the frictional strength of a pure chrysotile gouge at temperatures to 290??C and axial-shortening velocities as low as 0.001 ??m/s. As temperature increases to ???100??C, the strength of the chrysotile gouge decreases slightly at low velocities, but at temperatures ???200??C, it is substantially stronger and essentially independent of velocity at the lowest velocities tested. We estimate that pure chrysotile gouge at hydrostatic fluid pressure and appropriate temperatures would have shear strength averaged over a depth of 14 km of 50 MPa. Thus, on the sole basis of its strength, chrysotile cannot be the cause of a weak San Andreas fault. However, chrysotile may also contribute to low fault strength by forming mineral seals that promote the development of high fluid pressures.

  15. Description of Peripheral Muscle Strength Measurement and Correlates of Muscle Weakness in Patients Receiving Prolonged Mechanical Ventilatory Support

    PubMed Central

    Chlan, Linda L.; Tracy, Mary Fran; Guttormson, Jill; Savik, Kay

    2015-01-01

    Background Intensive Care Unit Acquired Weakness (ICUAW) is a frequent complication of critical illness due to immobility and prolonged mechanical ventilatory support. Objectives To describe daily peripheral muscle strength measurement in ventilated patients and explore relationships among factors that influence ICUAW. Methods Peripheral muscle strength of 120 ventilated ICU patients (mean age 59.8 ± 15.1; 51% female; APACHE III 61.3 ± 20.7; ICU stay 10.6 ± 8.6 days) was measured daily using a standardized hand grip dynamometry protocol. Three grip measurements for each hand were recorded in pounds-force; the mean of these three assessments was used in the analysis. Correlates of ICUAW were analyzed with mixed models to explore their relationship to grip strength (age, gender, illness severity, length of ventilatory support, medications). Results Median baseline grip strength was variable yet diminished (7.7; 0-102) with either a pattern of diminishing grip strength or maintenance of the baseline low grip strength over time. Controlling for days on protocol, female gender [β = −10.4(2.5); p = <.001], age [= −.24(.08); p = .004], and days receiving ventilatory support [= −.34(.12); p = .005] explained a significant amount of variance in grip strength over time. Conclusions Patients receiving prolonged periods of mechanical ventilatory support in this sample show marked decrements in grip strength measured by hand dynamometry, a marker for peripheral muscle strength. Hand dynamometry is a reliable method to measure muscle strength in cooperative ICU patients and can be used in future research to ultimately develop interventions to prevent ICUAW. PMID:26523017

  16. 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

  17. 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…

  18. 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

  19. 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.

  20. 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

  1. 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…

  2. 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

  3. 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.

  4. 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

  5. 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

  6. Systematic Reviews and Meta-Analyses - Literature-based Recommendations for Evaluating Strengths, Weaknesses, and Clinical Value.

    PubMed

    Beitz, Janice M; Bolton, Laura L

    2015-11-01

    Good quality systematic reviews (SRs) summarizing best available evidence can help inform clinical decisions, improv- ing patient and wound outcomes. Weak SRs can misinform readers, undermining care decisions and evidence-based practice. To examine the strengths and weaknesses of SRs and meta-analyses and the role of SRs in contemporary evidence-based wound care practice, and using the search terms systematic review, meta-analysis, and evidence-based practice, the authors searched Medline and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for important terminology and recommendations to help clinicians evaluate SRs with meta-analysis. Reputable websites, recent textbooks, and synthesized available literature also were reviewed to describe and summarize SR strengths and weaknesses. After developing a checklist for critically evaluating SR objectives, inclusion/exclusion criteria, study quality, data extraction and synthesis methods, meta-analysis homogeneity, accuracy of results, interpretation, and consistency between significant findings and abstract or conclusions, the checklist was applied to topical wound care SRs identified in Cochrane and MEDLINE searches. Best available evidence included in the SRs from 169 randomized controlled trials on 11,571 patients supporting topical intervention healing effects on burns, surgical sites, and diabetic, venous, or pressure ulcers was summarized and showed SRs and clinical trials can demonstrate different outcomes because the information/data are compiled differently. The results illustrate how evidence insufficient to support firm conclusions may still meet immediate needs to guide carefully considered clinical wound and patient care decisions while encouraging better future science. PMID:26544016

  7. 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.

  8. 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

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

    PubMed

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

    2015-12-31

    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

  10. 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

  11. 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

  12. ANALYSIS OF RILERS, AN ISOLEUCYL-TRNA SYNTHETASE GENE ASSOCIATED WITH MUPIROCIN PRODUCTION BY PSUEDOMONAS FLUORESCENS NCIMB 10586

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 c...

  13. Identifying strengths and weaknesses in the utilization of Objective Structured Clinical Examination (OSCE) in a nursing program.

    PubMed

    McWilliam, Paula L; Botwinski, Carol A

    2012-01-01

    Objective Structured Clinical Examination (OSCE) is used in nursing to assess students' transfer of classroom and laboratory learning experiences into simulated clinical practice. OSCE is a performance-based exam in which students are observed demonstrating a multitude of clinical behaviors. The purpose of this study was to identify strengths and weaknesses in the utilization of OSCE in this nursing program with 60 full-time students ages 21 to 23. An evaluation methodology was used for this study. Interviews were conducted with two groups: faculty facilitators of OSCE and standardized patients (SPs). Areas of focus were: data collection of students' performance, SP selection and training, and modification of the Nursing Interview Interaction Scale (NIIS). It was found that with appropriate SP selection and training, utilization of appropriate tools, and good data collection, OSCE can offer a valid and reliable means of testing nursing students' clinical competencies. PMID:22416539

  14. 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

  15. Chlorhexidine and Mupirocin Susceptibilities of Methicillin-Resistant Staphylococcus aureus from Colonized Nursing Home Residents

    PubMed Central

    Murphy, Courtney R.; Diekema, Daniel J.; Quan, Victor; Kim, Diane S.; Peterson, Ellena M.; Evans, Kaye D.; Tan, Grace L.; Hayden, Mary K.; Huang, Susan S.

    2013-01-01

    Chlorhexidine and mupirocin are used in health care facilities to eradicate methicillin-resistant Staphylococcus aureus (MRSA) carriage. The objective of this study was to assess the frequency of chlorhexidine and mupirocin resistance in isolates from nares carriers in multiple nursing homes and to examine characteristics associated with resistance. Nasal swab samples were collected from approximately 100 new admissions and 100 current residents in 26 nursing homes in Orange County, CA, from October 2008 to May 2011. MRSA isolates were tested for susceptibility by using broth microdilution, disk diffusion, and Etest; for genetic relatedness using pulsed-field gel electrophoresis; and for qac gene carriage by PCR. Characteristics of the nursing homes and their residents were collected from the Medicare Minimum Data Set and Long-Term Care Focus. A total of 829 MRSA isolates were obtained from swabbing 3,806 residents in 26 nursing homes. All isolates had a chlorhexidine MIC of ≤4 μg/ml. Five (0.6%) isolates harbored the qacA and/or qacB gene loci. Mupirocin resistance was identified in 101 (12%) isolates, with 78 (9%) isolates exhibiting high-level mupirocin resistance (HLMR). HLMR rates per facility ranged from 0 to 31%. None of the isolates with HLMR displayed qacA or qacB, while two isolates carried qacA and exhibited low-level mupirocin resistance. Detection of HLMR was associated with having a multidrug-resistant MRSA isolate (odds ratio [OR], 2.69; P = 0.004), a history of MRSA (OR, 2.34; P < 0.001), and dependency in activities of daily living (OR, 1.25; P = 0.004). In some facilities, HLMR was found in nearly one-third of MRSA isolates. These findings may have implications for the increasingly widespread practice of MRSA decolonization using intranasal mupirocin. PMID:23147721

  16. 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

  17. Prevalence of qacA/B Genes and Mupirocin Resistance Among Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates in the Setting of Chlorhexidine Bathing Without Mupirocin.

    PubMed

    Warren, David K; Prager, Martin; Munigala, Satish; Wallace, Meghan A; Kennedy, Colleen R; Bommarito, Kerry M; Mazuski, John E; Burnham, Carey-Ann D

    2016-05-01

    OBJECTIVE We aimed to determine the frequency of qacA/B chlorhexidine tolerance genes and high-level mupirocin resistance among MRSA isolates before and after the introduction of a chlorhexidine (CHG) daily bathing intervention in a surgical intensive care unit (SICU). DESIGN Retrospective cohort study (2005-2012) SETTING A large tertiary-care center PATIENTS Patients admitted to SICU who had MRSA surveillance cultures of the anterior nares METHODS A random sample of banked MRSA anterior nares isolates recovered during (2005) and after (2006-2012) implementation of a daily CHG bathing protocol was examined for qacA/B genes and high-level mupirocin resistance. Staphylococcal cassette chromosome mec (SCCmec) typing was also performed. RESULTS Of the 504 randomly selected isolates (63 per year), 36 (7.1%) were qacA/B positive (+) and 35 (6.9%) were mupirocin resistant. Of these, 184 (36.5%) isolates were SCCmec type IV. There was a significant trend for increasing qacA/B (P=.02; highest prevalence, 16.9% in 2009 and 2010) and SCCmec type IV (P<.001; highest prevalence, 52.4% in 2012) during the study period. qacA/B(+) MRSA isolates were more likely to be mupirocin resistant (9 of 36 [25%] qacA/B(+) vs 26 of 468 [5.6%] qacA/B(-); P=.003). CONCLUSIONS A long-term, daily CHG bathing protocol was associated with a change in the frequency of qacA/B genes in MRSA isolates recovered from the anterior nares over an 8-year period. This change in the frequency of qacA/B genes is most likely due to patients in those years being exposed in prior admissions. Future studies need to further evaluate the implications of universal CHG daily bathing on MRSA qacA/B genes among hospitalized patients. Infect Control Hosp Epidemiol 2016;37:590-597. PMID:26828094

  18. Rare occurrence of mupirocin resistance among clinical Staphylococcus isolates in Jordan.

    PubMed

    Aqel, Amin Abdelfattah; Ibrahim, Abdallah; Shehabi, Asem

    2012-06-01

    Staphylococcal infections have high occurrence in Jordanian patients. This study was carried out to determine the rates of high- and low-level mupirocin resistance (MupH and MupL) among staphylococci with the molecular characterization. Two hundred and thirty-two non-duplicate Staphylococcus spp. isolated from different clinical specimens were tested for mupirocin susceptibility using disk diffusion method and minimum inhibitory concentration (MIC). Resistance genes and clone relatedness was studied using polymerase chain reaction (PCR) and enterobacterial repetitive intergenic consensus primers (Eric-PCR) for the latter. Plasmid curing was performed to determine the genetic location of MupA gene. Among the 232 strains, 144 (62%) were methicillin-resistant Staphylococcus aureus (MRSA), 33 (14.2%) methicillin-susceptible Staphylococcus aureus (MSSA) and 55 (23.7%) were of other coagulase-negative Staphylococcus spp. (CoNS). Of all strains tested, only 6 (2.6%) were mupirocin resistant. MecA gene was detected in both MupL and MupH strains but MupA gene was only detected in MupH. Plasmid curing improved the plasmidic location of MupA gene. Molecular typing by Eric-PCR method revealed heterogenicity of the genetic make up of our MupL and MupH strains. Staphylococci with MupA-carrying genes are present in Jordanian hospitals, but thank to the limited use of mupirocin, they remain rare. PMID:22750783

  19. Clinical Effectiveness of Mupirocin for Preventing Staphylococcus aureus Infections in Nonsurgical Settings: A Meta-analysis.

    PubMed

    Nair, Rajeshwari; Perencevich, Eli N; Blevins, Amy E; Goto, Michihiko; Nelson, Richard E; Schweizer, Marin L

    2016-03-01

    A systematic literature review and meta-analysis was performed to identify effectiveness of mupirocin decolonization in prevention of Staphylococcus aureus infections, among nonsurgical settings. Of the 15 662 unique studies identified up to August 2015, 13 randomized controlled trials, 22 quasi-experimental studies, and 1 retrospective cohort study met the inclusion criteria. Studies were excluded if mupirocin was not used for decolonization, there was no control group, or the study was conducted in an outbreak setting. The crude risk ratios were pooled (cpRR) using a random-effects model. We observed substantial heterogeneity among included studies (I(2) = 80%). Mupirocin was observed to reduce the risk for S. aureus infections by 59% (cpRR, 0.41; 95% confidence interval [CI], .36-.48) and 40% (cpRR, 0.60; 95% CI, .46-.79) in both dialysis and nondialysis settings, respectively. Mupirocin decolonization was protective against S. aureus infections among both dialysis and adult intensive care patients. Future studies are needed in other settings such as long-term care and pediatrics. PMID:26503378

  20. Multiple mechanisms to ameliorate the fitness burden of mupirocin resistance in Salmonella typhimurium.

    PubMed

    Paulander, Wilhelm; Maisnier-Patin, Sophie; Andersson, Dan I

    2007-05-01

    We examined how the fitness costs of mupirocin resistance caused by mutations in the chromosomal isoleucyl-tRNA synthetase gene (ileS) can be ameliorated. Mupirocin-resistant mutants were isolated and four different, resistance-conferring point mutations in the chromosomal ileS gene were identified. Fifty independent lineages of the low-fitness, resistant mutants were serially passaged to evolve compensated mutants with increased fitness. In 34/50 of the evolved lineages, the increase in fitness resulted from additional point mutations in isoleucine tRNA synthetase (IleRS). Measurements in vitro of the kinetics of aminoacylation of wild-type and mutant enzymes showed that resistant IleRS had a reduced rate of aminoacylation due to altered interactions with both tRNAIle and ATP. The intragenic compensatory mutations improved IleRS kinetics towards the wild-type enzyme, thereby restoring bacterial fitness. Seven of the 16 lineages that lacked second-site compensatory mutations in ileS, showed an increase in ileS gene dosage, suggesting that an increased level of defective IleRS compensate for the decrease in aminoacylation activity. Our findings show that the fitness costs of ileS mutations conferring mupirocin resistance can be reduced by several types of mechanisms that may contribute to the stability of mupirocin resistance in clinical settings. PMID:17501926

  1. 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…

  2. 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.…

  3. 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…

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Weak-interaction strength from charge-exchange reactions versus {beta} decay in the A=40 isoquintet

    SciTech Connect

    Bhattacharya, M.; Goodman, C. D.; Garcia, A.

    2009-11-15

    We report a measurement of the Gamow-Teller (GT) strength distribution for {sup 40}Ar{yields}{sup 40}K using the 0 deg. (p,n) reaction. The measurement extends observed GT strength distribution in the A=40 system up to an excitation energy of {approx}8 MeV. In comparing our results with those from the {beta} decay of the isospin mirror nucleus {sup 40}Ti, we find that, within the excitation energy region probed by the {beta}-decay experiment, we observe a total GT strength that is in fair agreement with the {beta}-decay measurement. However, we find that the relative strength of the two strongest transitions differs by a factor of {approx}1.8 in comparing our results from (p,n) reactions with the {beta} decay of {sup 40}Ti. Using our results we present the neutrino-capture cross section for {sup 40}Ar.

  10. 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.

  11. 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. PMID:27133306

  12. Transfer of mupirocin resistance from Staphylococcus haemolyticus clinical strains to Staphylococcus aureus through conjugative and mobilizable plasmids.

    PubMed

    Rossi, Ciro C; Ferreira, Natália C; Coelho, Marcus L V; Schuenck, Ricardo P; Bastos, Maria do Carmo de F; Giambiagi-deMarval, Marcia

    2016-07-01

    Coagulase-negative staphylococci are thought to act as reservoirs of antibiotic resistance genes that can be transferred to Staphylococcus aureus, thus hindering the combat of this bacterium. In this work, we analyzed the presence of plasmids conferring resistance to the antibiotic mupirocin-widely used to treat and prevent S. aureus infections in hospital environments-in nosocomial S. haemolyticus strains. About 12% of the 75 strains tested were resistant to mupirocin, and this phenotype was correlated with the presence of plasmids. These plasmids were shown to be diverse, being either conjugative or mobilizable, and capable of transferring mupirocin resistance to S. aureus Our findings reinforce that S. haemolyticus, historically and mistakenly considered as a less important pathogen, is a reservoir of resistance genes which can be transferred to other bacteria, such as S. aureus, emphasizing the necessity of more effective strategies to detect and combat this emergent opportunistic pathogen. PMID:27190144

  13. Prevalence of High and Low Level Mupirocin Resistance among Staphylococcal Isolates from Skin Infection in a Tertiary Care Hospital

    PubMed Central

    S., Jayakumar; M., Meerabai; A.S., Shameem Banu; Mathew, Renu; M., Kalyani; Lal Y., Binesh

    2013-01-01

    Background: Mupirocin has been used for the treatment of skin infections and for the eradication of the nasal carriage of Methicillin -resistant Staphylococcus aureus (MRSA). The increased use of this antibiotic has been accompanied by its resistance, resulting in treatment failures. Objective: This study was aimed at determining the prevalences of low and high level Mupirocin resistance among the clinical isolates of Staphylococcus species which were obtained from pyogenic infections. Material and Method: Clinical samples such as wound swabs, tissues and pus which were submitted to the microbiology laboratory during a period of six months were screened for the growth of Staphylococcus species, which were identified as Staphylococcus aureus and Coagulase negative Staphylococcus species by the routine microbiological procedures. All the isolates were tested for their Mupirocin susceptibilities by using 5 and 200 μg discs and their resistance was confirmed from their Minimum Inhibitory Concentrations (MICs). Result: Out of 400 samples, 150 samples grew Staphylococcus species, of which 113 were Staphylococcus aureus and 37 were Coagulase negative Staphylococcus (CoNS). Only 5(3.3%) mupirocin resistant Staphylococcus species: three high level and two low level strains were detected. The MICs for the two low level and three high level Mupirocin resistant strains were 256 mg/L and ≥512mg/L each respectively. Conclusion: We conclude that the screening for mupirocin resistance, in terms of high-level and low-level resistance among the Staphylococcus species from patients with skin and soft tissue infections is warranted and that it is important for the clinicians in selecting the appropriate, empirical, topical, antimicrobial therapy. It also provides useful information about the prevalence of these resistant pathogens. PMID:23543635

  14. French Version of the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviors (SWAN-F) Questionnaire

    PubMed Central

    Robaey, Philippe; Amre, Devendra; Schachar, Russell; Simard, Louise

    2007-01-01

    Objective To evaluate internal and external consistency of a French adaptation of the SWAN (a 7-point rating strength-based scale, from far below to far above average) and its accuracy as a diagnostic test among children with Attention Deficit/Hyperactivity Disorder (ADHD). Method Parents of 88 children referred for ADHD were interviewed using the SWAN-F, a structured interview (DISC-4.0) and the Conners’ Rating Scale. Internal consistency and divergent and convergent validity of the SWAN-F were examined using the DISC-4.0 and Conners’ Rating Scales as reference standards for four dimensions: Inattention, Hyperactivity/Impulsivity, ADHD, Oppositional Defiant Disorder. Results The internal consistency of SWAN-F was within acceptable ranges for all dimensions (Cronbach’s alpha greater than 0.80). Scores of the SWAN-F subscales were strongly associated with the DISC-4.0 diagnostic assignments and Conners’ Rating Scales, following logical patterns of correspondence between diagnoses. Its accuracy as a diagnostic test was comparable to Conners’ Rating Scale, with a lower rate of false positives. Conclusions The information gathered with the SWAN-F is compatible with that obtained using the DISC-4.0 and Conners’ Rating Scale. Strength-based rating scales have the potential to evaluate the normal distribution of behaviors and to provide reliable cut-off defining abnormal behavior. PMID:18392156

  15. 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.

  16. Floods and health in Gambella region, Ethiopia: a qualitative assessment of the strengths and weaknesses of coping mechanisms

    PubMed Central

    Wakuma Abaya, Samson; Mandere, Nicodemus; Ewald, Göran

    2009-01-01

    Background Floods are the most frequent and devastating type of natural disaster worldwide, causing unprecedented deaths, diseases, and destruction of property and crops. Flooding has a greater impact in developing countries due to lack of sufficient disaster management structures and a lack of economic resources. Objective This study was conducted with the aim of contributing to the knowledge base of development strategies that reduce flood-related health risks in developing countries. The study focused particularly on assessing the flood risks and health-related issues in the Gambella region of Ethiopia; with the intent of producing relevant information to assist with the improvements in the efficacy of the current flood coping strategies in the region. Methods Data were gathered through interviews with 14 officers from different government and non-governmental organizations and a questionnaire survey given to 35 flood victims in Itang woreda. A qualitative approach was applied and the data were analyzed using content analysis. Results It was found that flooding is a common problem in Gambella region. The findings also indicate that the flood frequency and magnitude has increased rapidly during the last decade. The increase in floods was driven mainly by climate change and changes in land use, specifically deforestation. The reported main impacts of flooding on human health in Gambella region were deaths, injuries, and diseases such as malaria and diarrhea. Another notable consequence of flooding was crop destruction and subsequent malnutrition. Conclusions Three weaknesses that were identified in the current coping strategies for flood-related health impacts in Gambella region were a lack of flood-specific policy, absence of risk assessment, and weak institutional capacity. This study recommends new policy approaches that will increase the effectiveness of the current flood coping strategies to sustainably address the impact of flooding on human health. PMID

  17. 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.

  18. Nasal carriage of Methicillin- and Mupirocin-resistant S. aureus among health care workers in a tertiary care hospital

    PubMed Central

    Agarwal, Loveleena; Singh, Amit Kumar; Sengupta, Chandrim; Agarwal, Amitabh

    2015-01-01

    Objective: Methicillin-resistant Staphylococcus aureus (MRSA) ranks top among the nosocomial pathogens. Nasal formulation of mupirocin is found to eradicate MRSA from colonized individuals, but the emergence of resistant strains is a matter of concern. Methods: Nasal swabs were collected from 200 health care workers (HCWs) who were screened for MRSA. Kirby–Bauer disc diffusion method was used to perform antibiotic susceptibility test. MRSA detection was done using a cefoxitin 30 µg disc and interpreted according to the Clinical and Laboratory Standards Institute guidelines. Determination of mupirocin resistance was performed using Epsilometer test (E-test). Findings: About 14% of HCWs showed nasal carriage of MRSA. Nursing orderlies were the predominant carriers. E-test showed four mupirocin resistant isolates. The antibiogram of the MRSA isolates revealed the higher resistance to antibiotics as compared to methicillin-sensitive Staphylococcus aureus. All the MRSA isolates were sensitive to linezolid. Conclusion: HCWs in our hospital showed high nasal carriage rate of MRSA, particularly the nursing orderlies which is statistically significant. It is advisable to detect mupirocin resistance among the isolates obtained from the HCWs so that in case of resistance, alternative treatment should be sought. PMID:26645023

  19. 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

  20. Examining hand dominance using dynamometric grip strength testing as evidence for overwork weakness in Charcot-Marie-Tooth disease: a systematic review and meta-analysis.

    PubMed

    Roberts-Clarke, Daniel; Fornusek, Che; Fiatarone Singh, Maria A; Burns, Joshua; Hackett, Daniel A

    2016-09-01

    This systematic review with a meta-analysis of studies was carried out to evaluate the potential of overwork weakness on the basis of grip strength of dominant and nondominant hands in individuals with Charcot-Marie-Tooth disease (CMT). Numerous electronic databases were searched from the earliest records to February 2016. Studies of any design including participants older than 18 years of age with a confirmed diagnosis of CMT that measured grip strength of both hands using dynamometric testing were eligible for inclusion. Of 12 593 articles identified following removal of duplicates, five articles fulfilled the criteria. A total of 166 participants, mostly with CMT1 or CMT2, were described from the studies included. Hand and finger pinch grip strength for the dominant compared with the nondominant hand was not statistically different. There is no definitive evidence that preferential use of the dominant hand in CMT impairs function relative to the nondominant hand. Thus, robust exercise trials of progressive resistance training are needed to understand the extent of adaptations possible and provide evidence of the safety of such regimens. PMID:27177353

  1. Strength and Function Response to Clinical Interventions of Older Women Categorized by Weakness and Low Lean Mass Using Classifications From the Foundation for the National Institute of Health Sarcopenia Project

    PubMed Central

    Fragala, Maren S.; Dam, Thuy-Tien L.; Barber, Vanessa; Judge, James O.; Studenski, Stephanie A.; Cawthon, Peggy M.; McLean, Robert R.; Harris, Tamara B.; Ferrucci, Luigi; Guralnik, Jack M.; Kiel, Douglas P.; Kritchevsky, Stephen B.; Shardell, Michelle D.; Vassileva, Maria T.

    2015-01-01

    Background. The Foundation for the National Institutes of Health Sarcopenia Project developed data-driven cut-points for clinically meaningful weakness and low lean body mass. This analysis describes strength and function response to interventions based on these classifications. Methods. In data from four intervention studies, 378 postmenopausal women with baseline and 6-month data were evaluated for change in grip strength, appendicular lean mass corrected for body mass index, leg strength and power, and short physical performance battery (SPPB). Clinical interventions included hormones, exercise, and nutritional supplementation. Differences in outcomes were evaluated between (i) those with and without weakness and (ii) those with weakness and low lean mass or with one but not the other. We stratified analyses by slowness (walking speed ≤ 0.8 m/s) and by treatment assignment. Results. The women (72±7 years; body mass index of 26±5kg/m2) were weak (33%), had low lean mass (14%), or both (6%). Those with weakness increased grip strength, lost less leg power, and gained SPPB score (p < .05) compared with nonweak participants. Stratified analyses were similar for grip strength and SPPB. With lean mass in the analysis, individuals with weakness had larger gains in grip strength and SPPB scores regardless of low lean mass (p < .01). Conclusions. Older women with clinically meaningful muscle weakness increased grip strength and SPPB, regardless of the presence of low lean mass following treatment with interventions for frailty. Thus, results suggest that muscle weakness, as defined by the Foundation for the National Institutes of Health Sarcopenia Project, appears to be a treatable symptom. PMID:25135999

  2. 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…

  3. 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

  4. 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

  5. Sol-gel processed mupirocin silica microspheres loaded collagen scaffold: a synergistic bio-composite for wound healing.

    PubMed

    Perumal, Sathiamurthi; Ramadass, Satiesh kumar; Madhan, Balaraman

    2014-02-14

    Development of a bio-composite using synergistic combination is a promising strategy to address various pathological manifestations of acute and chronic wounds. In the present work, we have combined three materials viz., mupirocin as an antimicrobial drug, sol-gel processed silica microsphere as drug carrier for sustained delivery of drug and collagen, an established wound healer as scaffold. The mupirocin-loaded silica microspheres (Mu-SM) and Mu-SM loaded collagen scaffold were characterized for surface morphology, entrapment efficiency and distribution homogeneity, in vitro drug release, water uptake capacity, cell proliferation and antibacterial activity. In vivo wound healing efficacy of the bio-composite was experimented using full thickness excision wound model in Wistar albino rats. The Mu-SM incorporated collagen scaffold showed good in vitro characteristics in terms of better water uptake, sustained drug availability and antimicrobial activity. The wound closure analysis revealed that the complete epithelialisation was observed at 14.2 ± 0.44 days for Mu-SM loaded collagen, whereas this was 17.4 ± 0.44 days and 20.6 ± 0.54 days for collagen and control groups, respectively. Consequently, the synergistic strategy of combining mupirocin-loaded silica microspheres and collagen as a Mu-SM loaded collagen dressing material would be an ideal biomaterial for the treatment of surface wounds, burns and foot ulcers. PMID:24514452

  6. 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

  7. New Quadriplex PCR Assay for Detection of Methicillin and Mupirocin Resistance and Simultaneous Discrimination of Staphylococcus aureus from Coagulase-Negative Staphylococci

    PubMed Central

    Zhang, Kunyan; Sparling, Jennifer; Chow, Barbara L.; Elsayed, Sameer; Hussain, Zafar; Church, Deirdre L.; Gregson, Daniel B.; Louie, Thomas; Conly, John M.

    2004-01-01

    Major challenges in diagnostic molecular microbiology are to develop a simple assay to distinguish Staphylococcus aureus from the less virulent but clinically important coagulase-negative staphylococci (CoNS) and to simultaneously determine their antibiotic resistance profiles. Multiplex PCR assays have been developed for the detection of methicillin- and mupirocin-resistant S. aureus and CoNS but not for the simultaneous discrimination of S. aureus from CoNS. We designed a new set of Staphylococcus genus-specific primers and developed a novel quadriplex PCR assay targeting the 16S rRNA (Staphylococcus genus specific), nuc (S. aureus species specific), mecA (a determinant of methicillin resistance), and mupA (a determinant of mupirocin resistance) genes to identify most staphylococci, to discriminate S. aureus from CoNS and other bacteria, and to simultaneously detect methicillin and mupirocin resistance. Validation of the assay with 96 ATCC control strains and 323 previously characterized clinical isolates, including methicillin- and mupirocin-sensitive and -resistant S. aureus and CoNS isolates and other bacteria, demonstrated 100% sensitivity, specificity, and accuracy. This assay represents a simple, rapid, accurate, and reliable approach for the detection of methicillin- and mupirocin-resistant staphylococci and offers the hope of preventing their widespread dissemination through early and reliable detection. PMID:15528678

  8. 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

  9. Methicillin-resistant Staphylococcus aureus in Stockholm, Sweden: Molecular epidemiology and antimicrobial susceptibilities to ceftaroline, linezolid, mupirocin and vancomycin in 2014.

    PubMed

    Fang, Hong; Fröding, Inga; Gian, Boisan; Hæggman, Sara; Tollström, Ulla-Britt; Ullberg, Måns; Nord, Carl Erik

    2016-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a public health problem worldwide. The aim of the present study was to investigate the molecular epidemiology and antimicrobial susceptibilities of MRSA strains in Stockholm, Sweden in 2014. Pulsed-field gel electrophoresis (PFGE) was used to characterise the strains. Antimicrobial susceptibilities to ceftaroline, linezolid and mupirocin were determined by the disc diffusion method. Etest was used to determine vancomycin susceptibility and to confirm resistance to ceftaroline, mupirocin and linezolid in non-susceptible strains. High-level ceftaroline-resistant strains [minimum inhibitory concentration (MIC)≥4mg/L] were confirmed by the broth microdilution method. spa typing was carried out on strains that were non-susceptible to the antibiotics tested. In total, 743 consecutive non-duplicate MRSA strains recovered in Stockholm in 2014 were investigated. PFGE analysis of the isolates revealed a population with 271 different PFGE patterns and three non-typeable strains. No PFGE type accounted for >10% of all strains. The most common PFGE types were MRSA-00-02 (6.9%) and MRSA-05-02 (4.6%). MRSA-05-02 is a USA300-like strain. The antimicrobial susceptibilities of the strains were as follows: ceftaroline, 98.5%; linezolid, 100%; mupirocin, 99.3%; and vancomycin, 100%. Two strains with spa t001 displayed ceftaroline MICs of 4mg/L. Three strains with spa types t002, t064 and t437 showed high-level mupirocin resistance (MIC>1024mg/L). In conclusion, there was a diverse genetic population among the MRSA isolates and no predominant genotype was found. This study identified a few strains with high-level ceftaroline resistance, high-level mupirocin resistance and high-risk genotypes. PMID:27436463

  10. 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.

  11. Infrared weak quasars

    NASA Technical Reports Server (NTRS)

    Mcdowell, J. C.; Elvis, M.; Wilkes, B. J.

    1992-01-01

    Examples of quasars with anomalously weak IR emission are presented, and the effects of starlight subtraction on estimates of the UV and IR component strengths are discussed. Inferred model parameters are very sensitive to the position of the peak of the UV energy distribution. In many low redshift objects the peak is not seen; even in those objects where the turnover is clear, the turnover may not be intrinsic but instead due to reddening within the quasar host galaxy. The small number of unusual quasars with weak IR emission will be of utility as a probe of the quasar phenomenon in the absence of dominant dust reprocessing.

  12. 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

  13. Weak bump quasars

    NASA Technical Reports Server (NTRS)

    Wilkes, B. J.; Mcdowell, J.

    1994-01-01

    Research into the optical, ultraviolet and infrared continuum emission from quasars and their host galaxies was carried out. The main results were the discovery of quasars with unusually weak infrared emission and the construction of a quantitative estimate of the dispersion in quasar continuum properties. One of the major uncertainties in the measurement of quasar continuum strength is the contribution to the continuum of the quasar host galaxy as a function of wavelength. Continuum templates were constructed for different types of host galaxy and individual estimates made of the decomposed quasar and host continua based on existing observations of the target quasars. The results are that host galaxy contamination is worse than previously suspected, and some apparent weak bump quasars are really normal quasars with strong host galaxies. However, the existence of true weak bump quasars such as PHL 909 was confirmed. The study of the link between the bump strength and other wavebands was continued by comparing with IRAS data. There is evidence that excess far infrared radiation is correlated with weaker ultraviolet bumps. This argues against an orientation effect and implies a probable link with the host galaxy environment, for instance the presence of a luminous starburst. However, the evidence still favors the idea that reddening is not important in those objects with ultraviolet weak bumps. The same work has led to the discovery of a class of infrared weak quasars. Pushing another part of the envelope of quasar continuum parameter space, the IR-weak quasars have implications for understanding the effects of reddening internal to the quasars, the reality of ultraviolet turnovers, and may allow further tests of the Phinney dust model for the IR continuum. They will also be important objects for studying the claimed IR to x-ray continuum correlation.

  14. Fixing Employee Weaknesses: Addressing the Myth.

    ERIC Educational Resources Information Center

    Gilley, Jerry W.

    2001-01-01

    Suggests that human resources development professionals need to change their performance improvement focus and philosophy to embrace the importance of building on strengths and managing weaknesses. Identifies five characteristics indicative of employees' strengths. Describes seven strategies to help employees minimize their weaknesses while…

  15. Antimicrobial activity of mupirocin, daptomycin, linezolid, quinupristin/dalfopristin and tigecycline against vancomycin-resistant enterococci (VRE) from clinical isolates in Korea (1998 and 2005).

    PubMed

    Lee, Do Kyung; Kim, Yuna; Park, Kun Sup; Yang, Jae Wook; Kim, Kyungjae; Ha, Nam Joo

    2007-11-30

    It is a hot clinical issue whether newly approved antimicrobial agents such as daptomycin, linezolid, quinupristin/dalfopristin (synercid) and tigecycline are active enough to be used for infections caused by vancomycin resistant bacteria. We performed susceptibility tests for mupirocin, which is in widespread clinical use in Korea, and four new antimicrobials, daptomycin, linezolid, quinupristin/dalfopristin and tigecycline, against vancomycin-resistant Enterococcus faecalis and Enterococcus faecium isolated from Korean patients in 1998 and 2005 to evaluate and compare the in vitro activity of these antimicrobials. Among these agents, quinupristin/dalfopristin, which is rarely used in hospitals in Korea, showed relatively high resistance to several vancomycin-resistant enterococci (VRE) isolated in 2005. Likewise, daptomycin, linezolid and tigecycline have not yet been in clinical use in Korea. However, our results showed that most of the 2005 VRE isolates were already resistant to linezolid and daptomycin (highest minimum inhibitory concentration (MIC) value >100 microg/ml). Compared with the other four antimicrobial agents tested in this study, tigecycline generally showed the greatest activity against VRE. However, four strains of 2005 isolates exhibited resistance against tigecycline (MIC >12.5 microg/ml). Almost all VRE were resistant to mupirocin, whereas all E. faecium isolated in 1998 were inhibited at concentrations between 0.8 to approximately 1.6 microg/ml. In conclusion, resistances to these new antimicrobial agents were exhibited in most of VRE strains even though these new antibiotics have been rarely used in Korean hospitals. PMID:18047782

  16. Amplification of the gene for isoleucyl-tRNA synthetase facilitates adaptation to the fitness cost of mupirocin resistance in Salmonella enterica.

    PubMed

    Paulander, Wilhelm; Andersson, Dan I; Maisnier-Patin, Sophie

    2010-05-01

    Mutations that cause resistance to antibiotics in bacteria often reduce growth rate by impairing some essential cellular function. This growth impairment is expected to counterselect resistant organisms from natural populations following discontinuation of antibiotic therapy. Unfortunately (for disease control) bacteria adapt and improve their growth rate, often without losing antibiotic resistance. This adaptation process was studied in mupirocin-resistant (Mup(R)) strains of Salmonella enterica. Mupirocin (Mup) is an isoleucyl-adenylate analog that inhibits the essential enzyme, isoleucyl-tRNA synthetase (IleRS). Mutations causing Mup(R) alter IleRS and reduce growth rate. Fitness is restored by any of 23 secondary IleRS amino acid substitutions, 60% of which leave resistance unaffected. Evidence that increased expression of the original mutant ileS gene (Mup(R)) also improves fitness while maintaining resistance is presented. Expression can be increased by amplification of the ileS gene (more copies) or mutations that improve the ileS promoter (more transcription). Some adapted strains show both ileS amplification and an improved promoter. This suggests a process of adaptation initiated by common amplifications and followed by later acquisition of rare point mutations. Finally, a point mutation in one copy relaxes selection and allows loss of defective ileS copies. This sequence of events is demonstrated experimentally. A better understanding of adaptation can explain why antibiotic resistance persists in bacterial populations and may help identify drugs that are least subject to this problem. PMID:20176977

  17. 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.)

  18. 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.

  19. Rheology of weakly vibrated granular materials

    NASA Astrophysics Data System (ADS)

    Dijksman, J. A.; Wortel, G.; van Hecke, M.

    2009-06-01

    We show how weak vibrations substantially modify the rheology of granular materials. We experimentally probe dry granular flows in a weakly vibrated split bottom shear cell—the weak vibrations modulate gravity and act as an agitation source. By tuning the applied stress and vibration strength, and monitoring the resulting strain as a function of time, we uncover a rich phase diagram in which non-trivial transitions separate a jammed phase, a creep flow case, and a steady flow case.

  20. 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.

  1. 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. PMID:26008124

  2. 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. PMID:24387858

  3. Weak Value Theory

    SciTech Connect

    Shikano, Yutaka

    2011-03-28

    I show that the weak value theory is useful from the viewpoints of the experimentally verifiability, consistency, capacity for explanation as to many quantum paradoxes, and practical advantages. As an example, the initial state in the Hardy paradox can be experimentally verified using the weak value via the weak measurement.

  4. Weak Measurements Destroy Too Much Quantum Correlation

    NASA Astrophysics Data System (ADS)

    Wu, Shao-xiong; Zhang, Jun; Yu, Chang-shui; Song, He-shan

    2016-01-01

    The quantum correlation under weak measurements is studied via skew information. For 2 × d-dimensional states, it can be given by a closed form which linearly depends on the quantum correlation [EPL. 107 (2014) 10007] determined by the strength of the weak measurement. It is found that the quantum correlation under weak measurements only captures partial quantumness of the state. In particular, the extraction of the residual quantumness by the latter measurements will inevitably destroy too much quantumness. To demonstration, the Werner state is given as an example.

  5. 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

  6. 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

  7. 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.

  8. 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)

  9. 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.

  10. 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…

  11. 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. PMID:16092719

  12. 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…

  13. 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…

  14. Strengths and Weaknesses of Two New Potato Herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outlook (dimethenamid-p) and Chateau (flumioxazin) are two new preemergence herbicides labeled for use in potatoes. Both herbicides are restricted to preemergence applications only and improve nightshade control when tank mixed with other potato herbicides. Dimethenamid-p is particularly strong on ...

  15. 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.

  16. 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.

  17. Airway clearance in neuromuscular weakness.

    PubMed

    Gauld, Leanne Maree

    2009-05-01

    Impaired airway clearance leads to recurrent chest infections and respiratory deterioration in neuromuscular weakness. It is frequently the cause of death. Cough is the major mechanism of airway clearance. Cough has several components, and assessment tools are available to measure the different components of cough. These include measuring peak cough flow, respiratory muscle strength, and inspiratory capacity. Each is useful in assessing the ability to generate an effective cough, and can be used to guide when techniques of assisting airway clearance may be effective for the individual and which are most effective. Techniques to assist airway clearance include augmenting inspiration by air stacking, augmenting expiration by assisting the cough, and augmenting both inspiration and expiration with the mechanical insufflator-exsufflator or by direct suctioning via a tracheostomy. Physiotherapists are invaluable in assisting airway clearance, and in teaching patients and their families how to use these techniques. Use of the mechanical insufflator-exsufflator has gained popularity in recent times, but several simpler, more economical methods are available to assist airway clearance that can be used effectively alone or in combination. This review examines the literature available on the assessment and management of impaired airway clearance in neuromuscular weakness. PMID:19379290

  18. Comparison of the antibacterial effect of silver sulfadiazine 1%, mupirocin 2%, Acticoat and octenidine dihydrochloride in a full-thickness rat burn model contaminated with multi drug resistant Acinetobacter baumannii.

    PubMed

    Selçuk, Caferi Tayyar; Durgun, Mustafa; Ozalp, Burhan; Tekin, Alicem; Tekin, Recep; Akçay, Cemal; Alabalık, Ulaş

    2012-12-01

    In this study, our aim is to compare the efficacy of different topical antibacterial agents in a rat model contaminated with a multi drug resistant (MDR) standard Acinetobacter baumannii strain. The study was carried out on 40 Sprague-Dawley rats of 250-300 g each. For the purposes of this study, the rats were divided into 5 groups, with 8 rats in each group: Group 1 control; Group 2 silver sulfadiazine; Group 3 mupirocin; Group 4 Acticoat group; and Group 5 octenidine dihydrochloride group. Following to the formation of the full-thickness burn areas in rats, the MDR A. baumannii standard strain was inoculated into the burned area. The rats in all the groups were sacrificed at the end of the 10th day and subjected to histopathological and microbiological evaluation. In the histopathological evaluation, the lowest inflammatory cell response and bacterial density in the eschar and muscle tissues were observed in the Acticoat group. While these results were found to be statistically significant compared to the silver sulfadiazine group, only the bacterial density in the muscle tissue was found as significant in comparison to the mupirocin and octenidine groups. In the microbiological evaluation, the lowest growth in the muscle tissue culture among all the groups was observed in the Acticoat group. The growth in the eschar tissue culture was significantly lower in the Acticoat and octenidine groups in comparison to the silver sulfadiazine group. At the end of the study, it has been observed that Acticoat was effective both in eschar and muscle, while octenidine was effective in eschar tissues in a rat burn model contaminated with MDR A. baumannii. PMID:22688192

  19. Weak bump quasars

    NASA Technical Reports Server (NTRS)

    Mcdowell, Jonathan C.; Elvis, Martin; Wilkes, Belinda J.; Willner, Steven P.; Oey, M. S.

    1989-01-01

    The recent emphasis on big bumps dominating the UV continuum of quasars has obscured the facts that bump properties vary widely and that there are objects in which no such component is evident. As part of a survey of quasar continuum spectra, a class of quasars is identified in which the optical-UV continuum big bump feature appears to be weak or absent, relative to both IR and X-ray. These weak bump quasars are otherwise normal objects and constitute a few percent of the quasar population.

  20. 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.

  1. Anisotropy of weakly vibrated granular flows.

    PubMed

    Wortel, Geert H; van Hecke, Martin

    2015-10-01

    We experimentally probe the anisotropy of weakly vibrated flowing granular media. Depending on the driving parameters-flow rate and vibration strength-this anisotropy varies significantly. We show how the anisotropy collapses when plotted as a function of the driving stresses, uncovering a direct link between stresses and anisotropy. Moreover, our data suggest that for small anisotropies, the shear stresses vanish. Anisotropy of the fabric of granular media thus plays a crucial role in determining the rheology of granular flows. PMID:26565148

  2. Rheology of weakly vibrated granular media

    NASA Astrophysics Data System (ADS)

    Wortel, Geert H.; Dijksman, Joshua A.; van Hecke, Martin

    2014-01-01

    We probe the rheology of weakly vibrated granular flows as function of flow rate, vibration strength, and pressure by performing experiments in a vertically vibrated split-bottom shear cell. For slow flows, we establish the existence of a vibration-dominated granular flow regime, where the driving stresses smoothly vanish as the driving rate is diminished. We distinguish three qualitatively different vibration-dominated rheologies, most strikingly a regime where the shear stresses no longer are proportional to the pressure.

  3. 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

  4. How robust is human gait to muscle weakness?

    PubMed Central

    van der Krogt, Marjolein M.; Delp, Scott L.; Schwartz, Michael H.

    2015-01-01

    Humans have a remarkable capacity to perform complex movements requiring agility, timing, and strength. Disuse, aging, and disease can lead to a loss of muscle strength, which frequently limits the performance of motor tasks. It is unknown, however, how much weakness can be tolerated before normal daily activities become impaired. This study examines the extent to which lower limb muscles can be weakened before normal walking is affected. We developed muscle-driven simulations of normal walking and then progressively weakened all major muscle groups, one at the time and simultaneously, to evaluate how much weakness could be tolerated before execution of normal gait became impossible. We further examined the compensations that arose as a result of weakening muscles. Our simulations revealed that normal walking is remarkably robust to weakness of some muscles but sensitive to weakness of others. Gait appears most robust to weakness of hip and knee extensors, which can tolerate weakness well and without a substantial increase in muscle stress. In contrast, gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors. Weakness of individual muscles results in increased activation of the weak muscle, and in compensatory activation of other muscles. These compensations are generally inefficient, and generate unbalanced joint moments that require compensatory activation in yet other muscles. As a result, total muscle activation increases with weakness as does the cost of walking. By clarifying which muscles are critical to maintaining normal gait, our results provide important insights for developing therapies to prevent or improve gait pathology. PMID:22386624

  5. 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.

  6. Weaknesses in Underperforming Schools

    ERIC Educational Resources Information Center

    van de Grift, Wim; Houtveen, Thoni

    2007-01-01

    In some Dutch elementary schools, the average performance of students over several years is significantly below the level that could be expected of them. This phenomenon is known as "underperformance." The most important identifiable weaknesses that go along with this phenomenon are that (a) learning material offered at school is insufficient to…

  7. Weak Radial Artery Pulse

    PubMed Central

    Venugopalan, Poothirikovil; Sivakumar, Puthuval; Ardley, Robert G.; Oates, Crispian

    2012-01-01

    We present an 11year-old boy with a weak right radial pulse, and describe the successful application of vascular ultrasound to identify the ulnar artery dominance and a thin right radial artery with below normal Doppler flow velocity that could explain the discrepancy. The implications of identifying this anomaly are discussed. PMID:22375269

  8. Weak Lensing with LSST

    NASA Astrophysics Data System (ADS)

    Wittman, David M.; Jain, B.; Jarvis, M.; Knox, L.; Margoniner, V.; Takada, M.; Tyson, J.; Zhan, H.; LSST Weak Lensing Science Collaboration

    2006-12-01

    Constraining dark energy parameters with weak lensing is one of the primary science goals of the LSST. The LSST Weak Lensing Science Collaboration has been formed with the goal of optimizing the weak lensing science by optimizing the survey cadence; working with Data Management to insure high-quality pipeline processing which will meet our needs; developing the necessary analysis tools well before the onset of data-taking; participating in high-fidelity simulations to test the system end-to-end; and analyzing the real dataset as it becomes available. We review the major weak lensing probes, the twoand three-point shear correlations, and how they constrain dark energy parameters. We also review the possibility of going beyond dark energy models and testing gravity with the LSST data. To realize the promise of the awesome LSST statistical precision, we must ensure that systematic errors are kept under control. We review the major sources of systematics and our plans for mitigation. We present data that demonstrate that these sources of systematics can be kept to a level smaller than the statistical error.

  9. 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.

  10. Weak Interactions and Instability Cascades.

    PubMed

    Kadoya, Taku; McCann, Kevin S

    2015-01-01

    Food web theory states that a weak interactor which is positioned in the food web such that it tends to deflect, or mute, energy away from a potentially oscillating consumer-resource interaction often enhances community persistence and stability. Here we examine how adding other weak interactions (predation/harvesting) on the stabilizing weak interactor alters the stability of food web using a set of well-established food web models/modules. We show that such "weak on weak" interaction chains drive an indirect dynamic cascade that can rapidly ignite a distant consumer-resource oscillator. Nonetheless, we also show that the "weak on weak" interactions are still more stable than the food web without them, and so weak interactions still generally act to stabilize food webs. Rather, these results are best interpreted to say that the degree of the stabilizing effect of a given important weak interaction can be severely compromised by other weak interactions (including weak harvesting). PMID:26219561

  11. 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

  12. Weakly supervised glasses removal

    NASA Astrophysics Data System (ADS)

    Wang, Zhicheng; Zhou, Yisu; Wen, Lijie

    2015-03-01

    Glasses removal is an important task on face recognition, in this paper, we provide a weakly supervised method to remove eyeglasses from an input face image automatically. We choose sparse coding as face reconstruction method, and optical flow to find exact shape of glasses. We combine the two processes iteratively to remove glasses more accurately. The experimental results reveal that our method works much better than these algorithms alone, and it can remove various glasses to obtain natural looking glassless facial images.

  13. Asymptotically Safe Weak Interactions

    NASA Astrophysics Data System (ADS)

    Calmet, Xavier

    We emphasize that the electroweak interactions without a Higgs boson are very similar to quantum general relativity. The Higgs field could just be a dressing field and might not exist as a propagating particle. In that interpretation, the electroweak interactions without a Higgs boson could be renormalizable at the nonperturbative level because of a nontrivial fixed point. Tree-level unitarity in electroweak bosons scattering is restored by the running of the weak scale.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Strength loss in kraft pulping

    NASA Astrophysics Data System (ADS)

    Iribarne, Jose

    Unbleached kraft pulps from two U.S. mills were 21% and 26% weaker than comparable laboratory pulps from the same chip sources, when assessed as the tear index at a tensile index of 70 kN.m/kg. The phenomena involved were clarified by characterizing the differences between the mill and laboratory pulps in terms of fundamental fiber properties. All of the strength loss could be explained by a reduction in intrinsic fiber strength of 9% to 11%, as estimated from wet zero-span tensile tests and fiber length distributions. Most of the effects of different fiber shape and length were isolated by PFI mill refining and decrilling, respectively. The higher fiber coarseness of mill pulps was a factor in their maximum density and bond strength, but changes in these variables were analogous to those of laboratory pups due to similar swelling. Specific bond strength, determined from a wet pressing experiment, was similar in mill and laboratory pulps. Neither carbohydrate composition nor crystalline structure, assessed through x-ray diffraction analysis, were significant factors in the observed fiber strength differences. The mill pulps were not more heterogeneous than the laboratory pulps, within the resolution of a fractionation experiment. The number of weak points in each pulp was assessed through analysis of the amount of fiber cutting during PFI mill refining and treatments with potassium superoxide or cellulase. The results suggested that the chemistry of kraft pulping preferentially weaken short, slender fibers, while mechanical stresses during the hot discharge of batch digesters mainly affect long, thick fibers. The greater number of weak points in the long-fiber fractions of mill pulps is probably associated with their lower wet zero-span tensile indices. Automated optical detection of major singularities with a prototype instrument suggested that only the weak points induced by mechanical stress could be detected by local variations in birefringence. In contrast

  5. 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.

  6. Weak localization with nonlinear bosonic matter waves

    SciTech Connect

    Hartmann, Timo; Michl, Josef; Petitjean, Cyril; Wellens, Thomas; Urbina, Juan-Diego; Richter, Klaus; Schlagheck, Peter

    2012-08-15

    We investigate the coherent propagation of dilute atomic Bose-Einstein condensates through irregularly shaped billiard geometries that are attached to uniform incoming and outgoing waveguides. Using the mean-field description based on the nonlinear Gross-Pitaevskii equation, we develop a diagrammatic theory for the self-consistent stationary scattering state of the interacting condensate, which is combined with the semiclassical representation of the single-particle Green function in terms of chaotic classical trajectories within the billiard. This analytical approach predicts a universal dephasing of weak localization in the presence of a small interaction strength between the atoms, which is found to be in good agreement with the numerically computed reflection and transmission probabilities of the propagating condensate. The numerical simulation of this quasi-stationary scattering process indicates that this interaction-induced dephasing mechanism may give rise to a signature of weak antilocalization, which we attribute to the influence of non-universal short-path contributions. - Highlights: Black-Right-Pointing-Pointer Numerical simulation of scattering of Bose-Einstein condensate through billiards. Black-Right-Pointing-Pointer Novel analytical semiclassical theory for nonlinear coherent scattering. Black-Right-Pointing-Pointer Inversion of weak localization due to mean-field interaction within the condensate. Black-Right-Pointing-Pointer Relevance of non-universal short-path contributions.

  7. Universal mechanism for Anderson and weak localization.

    PubMed

    Filoche, Marcel; Mayboroda, Svitlana

    2012-09-11

    Localization of stationary waves occurs in a large variety of vibrating systems, whether mechanical, acoustical, optical, or quantum. It is induced by the presence of an inhomogeneous medium, a complex geometry, or a quenched disorder. One of its most striking and famous manifestations is Anderson localization, responsible for instance for the metal-insulator transition in disordered alloys. Yet, despite an enormous body of related literature, a clear and unified picture of localization is still to be found, as well as the exact relationship between its many manifestations. In this paper, we demonstrate that both Anderson and weak localizations originate from the same universal mechanism, acting on any type of vibration, in any dimension, and for any domain shape. This mechanism partitions the system into weakly coupled subregions. The boundaries of these subregions correspond to the valleys of a hidden landscape that emerges from the interplay between the wave operator and the system geometry. The height of the landscape along its valleys determines the strength of the coupling between the subregions. The landscape and its impact on localization can be determined rigorously by solving one special boundary problem. This theory allows one to predict the localization properties, the confining regions, and to estimate the energy of the vibrational eigenmodes through the properties of one geometrical object. In particular, Anderson localization can be understood as a special case of weak localization in a very rough landscape. PMID:22927384

  8. Phase Diagram of the Bose Hubbard Model with Weak Links

    NASA Astrophysics Data System (ADS)

    Hettiarachchilage, Kalani; Rousseau, Valy; Tam, Ka-Ming; Moreno, Juana; Jarrell, Mark; Sheehy, Daniel

    2012-02-01

    We study the ground state phase diagram of strongly interacting ultracold Bose gas in a one-dimensional optical lattice with a tunable weak link, by means of Quantum Monte Carlo simulation. This model contains an on-site repulsive interaction (U) and two different near-neighbor hopping terms, J and t, for the weak link and the remainder of the chain, respectively. We show that by reducing the strength of J, a novel intermediate phase develops which is compressible and non-superfluid. This novel phase is identified as a Normal Bose Liquid (NBL) which does not appear in the phase diagram of the homogeneous bosonic Hubbard model. Further, we find a linear variation of the phase boundary of Normal Bose Liquid (NBL) to SuperFluid (SF) as a function of the strength of the weak link. These results may provide a new path to design advanced atomtronic devices in the future.

  9. 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

  10. 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

  11. 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.

  12. Propagation of a curved weak shock

    NASA Astrophysics Data System (ADS)

    Monica, A.; Prasad, Phoolan

    2001-05-01

    Propagation of a curved shock is governed by a system of shock ray equations which is coupled to an infinite system of transport equations along these rays. For a two-dimensional weak shock, it has been suggested that this system can be approximated by a hyperbolic system of four partial differential equations in a ray coordinate system, which consists of two independent variables ([zeta], t) where the curves t = constant give successive positions of the shock and [zeta] = constant give rays. The equations show that shock rays not only stretch longitudinally due to finite amplitude on a shock front but also turn due to a non-uniform distribution of the shock strength on it. These changes finally lead to a modification of the amplitude of the shock strength. Since discontinuities in the form of kinks appear on the shock, it is necessary to study the problem by using the correct conservation form of these equations. We use such a system of equations in conservation form to construct a total-variation-bounded finite difference scheme. The numerical solution captures converging shock fronts with a pair of kinks on them the shock front emerges without the usual folds in the caustic region. The shock strength, even when the shock passes through the caustic region, remains so small that the small-amplitude theory remains valid. The shock strength ultimately decays with a well-defined geometrical shape of the shock front a pair of kinks which separate a central disc from a pair of wings on the two sides. We also study the ultimate shape and decay of shocks of initially periodic shapes and plane shocks with a dent and a bulge.

  13. 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.

  14. 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…

  15. Weak Deeply Virtual Compton Scattering

    SciTech Connect

    Ales Psaker; Wolodymyr Melnitchouk; Anatoly Radyushkin

    2007-03-01

    We extend the analysis of the deeply virtual Compton scattering process to the weak interaction sector in the generalized Bjorken limit. The virtual Compton scattering amplitudes for the weak neutral and charged currents are calculated at the leading twist within the framework of the nonlocal light-cone expansion via coordinate space QCD string operators. Using a simple model, we estimate cross sections for neutrino scattering off the nucleon, relevant for future high intensity neutrino beam facilities.

  16. Weak ferromagnetism in the cuprates

    NASA Astrophysics Data System (ADS)

    Chovan, J.; Papanicolaou, N.

    2001-02-01

    An effective field theory that describes the low-frequency spin dynamics in the low-temperature orthorhombic phase of La 2CuO 4 is derived. The main features of the inherent covert weak ferromagnetism are thus accounted for in a straightforward manner but some of the finer theoretical predictions would require further experimental investigation. In particular, theory predicts the occurrence of magnetic stripes in undoped La 2CuO 4 which mediate the observed weak-ferromagnetic transition.

  17. Influence of environmental noise on the weak value amplification

    NASA Astrophysics Data System (ADS)

    Zhu, Xuannmin; Zhang, Yu-Xiang

    2016-05-01

    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.

  18. 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.

  19. 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.

  20. Effective Teaching Strategies for Gifted/Learning-Disabled Students with Spatial Strengths

    ERIC Educational Resources Information Center

    Mann, Rebecca L.

    2006-01-01

    This study sought to determine effective teaching strategies for use with high-ability students who have spatial strengths and sequential weaknesses. Gifted students with spatial strengths and weak verbal skills often struggle in the traditional classroom. Their learning style enables them to grasp complex systems and excel at higher levels of…

  1. 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.

  2. Weakness

    MedlinePlus

    ... spine) Stroke MUSCLE DISEASES Becker muscular dystrophy Dermatomyositis Muscular dystrophy (Duchenne) Myotonic dystrophy POISONING Botulism Poisoning ( insecticides , nerve gas) Shellfish poisoning OTHER Anemia Myasthenia gravis Polio

  3. 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)

  4. 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.

  5. 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…

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Evolutionary behavior of weak shocks in a non-ideal gas

    NASA Astrophysics Data System (ADS)

    Arora, Rajan; Siddiqui, Mohd Junaid

    2013-03-01

    Except some empirical methods, which have been developed in the past, no analytical method exists to describe the evolutionary behavior of a shock wave without limiting its strength. In this paper, we have derived a system of transport equations for the shock strength and the induced continuity. We generate a completely intrinsic description of plane, cylindrical, and spherical shock waves of weak strength, propagating into a non-ideal gas. It is shown that for a weak shock, the disturbance evolves like an acceleration wave at the leading order. For a weak shock, we may assume that [InlineEquation not available: see fulltext.]. We have considered a case when the effect of the first order-induced discontinuity or the disturbances that overtook the shock from behind are strong, i.e., [ p x ] = O(1). The evolutionary behavior of the weak shocks in a non-ideal gas is described using the truncation approximation.

  11. 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.

  12. 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.

  13. Focal weakness following herpes zoster.

    PubMed Central

    Cockerell, O C; Ormerod, I E

    1993-01-01

    Three patients presented with focal weakness of an arm which followed segmental herpes zoster affecting the same limb. Neurophysiological investigations suggest that the site of the lesion lay at the root, plexus, or peripheral nerve level. This reflects the various ways in which the virus may affect the peripheral nervous system. PMID:8410022

  14. 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

  15. 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

  16. PROTOSTELLAR DISK FORMATION ENABLED BY WEAK, MISALIGNED MAGNETIC FIELDS

    SciTech Connect

    Krumholz, Mark R.; Crutcher, Richard M.; Hull, Charles L. H.

    2013-04-10

    The gas from which stars form is magnetized, and strong magnetic fields can efficiently transport angular momentum. Most theoretical models of this phenomenon find that it should prevent formation of large (>100 AU), rotationally supported disks around most protostars, even when non-ideal magnetohydrodynamic (MHD) effects that allow the field and gas to decouple are taken into account. Using recent observations of magnetic field strengths and orientations in protostellar cores, we show that this conclusion is incorrect. The distribution of magnetic field strengths is very broad, and alignments between fields and angular momentum vectors within protostellar cores are essentially random. By combining the field strength and misalignment data with MHD simulations showing that disk formation is expected for both weak and misaligned fields, we show that these observations imply that we should expect disk fractions of {approx}10%-50% even when protostars are still deeply embedded in their parent cores, and even if the gas is governed by ideal MHD.

  17. 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. PMID:25025187

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Recent Results on Singularity Strengths

    NASA Astrophysics Data System (ADS)

    Nolan, Brien

    2002-12-01

    In this contribution, we review some recent results on strengths of singularities. In a space-time (M,g), let γ[τ0, 0) → M be an incomplete, inextendible causal geodesic, affinely parametrised by τ, tangent ěc k. Let Jτ1 :=set of Jacobi fields along γ, orthogonal to γ and vanishing at time τ1 ≥ τ0 i.e. ěc ξ ∈ J{τ 1 } iff D2ξa = -Rbcdakbkdξc, gabξakb = 0, and ěc ξ (τ 1 ) = 0. Vτ1(τ) := volume element defined by full set of independent elements of Jτ1 (2-dim for null geodesies, 3-dim for time-like); Vτ1 := ∥Vτ1∥. Definition (Tipler 1977): γ terminates in a gravitationally strong singularity if for all 0 > τ1 ≥ τ0, lim infτ→0- Vτ1(τ) = 0. γ... gravitationally weak ... lim infτ→0- Vτ1(τ) > 0. The interpretation is that at a strong singularity, an extended body, e.g. a gravitational wave detector, is crushed to zero volume by the singularity. Tipler's definition does not take account of the possibility that (i) V → ∞ or (ii) V → finite, non-zero value, but with infinite stretching/crushing in orthogonal directions ('spaghettifying singularity'). Extended definition (Nolan 1999): strong if either V → 0,∞ or if for every τ1, there is an element ěc ξ of Jτ1 satisfying ||ěc ξ || -> 0. Otherwise weak. (Ori 2000): singularity is 'deformationally strong' if either (i) it is Tipler-strong or (ii) for every τ1, there is an element ěc ξ of Jτ1 satisfying ||ěc ξ || -> ∞ . Otherwise, deformationally weak...

  3. Tomography and weak lensing statistics

    SciTech Connect

    Munshi, Dipak; Coles, Peter; Kilbinger, Martin E-mail: peter.coles@astro.cf.ac.uk

    2014-04-01

    We provide generic predictions for the lower order cumulants of weak lensing maps, and their correlators for tomographic bins as well as in three dimensions (3D). Using small-angle approximation, we derive the corresponding one- and two-point probability distribution function for the tomographic maps from different bins and for 3D convergence maps. The modelling of weak lensing statistics is obtained by adopting a detailed prescription for the underlying density contrast that involves hierarchal ansatz and lognormal distribution. We study the dependence of our results on cosmological parameters and source distributions corresponding to the realistic surveys such as LSST and DES. We briefly outline how photometric redshift information can be incorporated in our results. We also show how topological properties of convergence maps can be quantified using our results.

  4. Overdamping by weakly coupled environments

    NASA Astrophysics Data System (ADS)

    Esposito, Massimiliano; Haake, Fritz

    2005-12-01

    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.

  5. 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.

  6. 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.

  7. 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.

  8. Assessment of respiratory muscle function and strength.

    PubMed Central

    Syabbalo, N.

    1998-01-01

    Measurement of respiratory muscle strength is useful in order to detect respiratory muscle weakness and to quantify its severity. In patients with severe respiratory muscle weakness, vital capacity is reduced but is a non-specific and relatively insensitive measure. Conventionally, inspiratory and expiratory muscle strength has been assessed by maximal inspiratory and expiratory mouth pressures sustained for 1 s (PImax and PEmax) during maximal static manoeuvre against a closed shutter. However, PImax and PEmax are volitional tests, and are poorly reproducible with an average coefficient of variation of 25%. The sniff manoeuvre is natural and probably easier to perform. Sniff pressure, and sniff transdiaphragmatic pressure are more reproducible and useful measure of diaphragmatic strength. Nevertheless, the sniff manoeuvre is also volition-dependent, and submaximal efforts are most likely to occur in patients who are ill or breathless. Non-volitional tests include measurements of twitch oesophageal, gastric and transdiaphragmatic pressure during bilateral electrical and magnetic phrenic nerve stimulation. Electrical phrenic nerve stimulation is technically difficult and is also uncomfortable and painful. Magnetic phrenic nerve stimulation is less painful and transdiaphragmatic pressure is reproducible in normal subjects. It is a relatively easy test that has the potential to become a widely adopted method for the assessment of diaphragm strength. The development of a technique to measure diaphragmatic sound (phonomyogram) during magnetic phrenic nerve stimulation opens the way for noninvasive assessment of diaphragmatic function. PMID:9683973

  9. Flexural strength and porosity of cements

    NASA Astrophysics Data System (ADS)

    Birchall, J. D.; Howard, A. J.; Kendall, K.

    1981-01-01

    A curious feature of hydraulic cements, such as those based on calcium silicate, calcium aluminate and calcium sulphate, is that they exhibit similarly low flexural strengths, typically between 3 and 10 MPa, despite their differing chemical composition, varying degrees of hydration and contrasting setting mechanisms1-3. Because of these low strength values, unreinforced cements are never used in flexure or tension, and studies of cement strength are usually confined to compression. Those few studies which have considered flexural or tensile failure have concluded that hydraulic cements have an intrinsic maximum tensile strength of about 20 MPa4,5. Here we demonstrate that the commonly observed flexural weakness of cement is due to the presence of large voids which are largely undetected by conventional methods of pore analysis such as gas adsorption and mercury porosimetry. The removal of such macro-defects results in flex strengths up to 70 MPa, despite the large volume of gel pores remaining in the material. These strength figures, comparable with those of sintered ceramics, have been achieved without the use of elevated pressures or temperatures, and without fibrous reinforcement.

  10. Preoperative indicators of motion loss and weakness following anterior cruciate ligament reconstruction.

    PubMed

    McHugh, M P; Tyler, T F; Gleim, G W; Nicholas, S J

    1998-06-01

    Loss of motion and knee extension weakness are recognized as significant complications following anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to determine 1) what degree of preoperative motion loss represents a risk for postoperative motion problems and 2) if preoperative weakness (deficit > or = 20%) affects return of strength following surgery. Measurements of range of motion and strength were made on 102 patients (56 men, 46 women; age = 31 +/- 1 years) within 2 weeks prior to ACL reconstruction (preop) and repeated 6 months following surgery (postop). Thirteen of 40 patients (33%) lacking > or = 5 degrees preop, eight of 20 patients (40%) lacking 1-4 degrees preop, and three of 42 (7%) patients with full extension preop had > or = 5 degrees loss 6 months postop (p < 0.001). Thirty-two of 39 (82%) patients with normal strength preop had weakness 6 months postop. Forty of 51 (78%) patients with preop knee extension weakness still had weakness 6 months postop. Preop strength was not a good predictor of residual weakness following ACL reconstruction. The magnitude of the preop extension loss appears not to be a risk factor. It is the presence or absence of full extension equal to the contralateral leg that identifies risk for postop problems regaining extension. PMID:9617726

  11. 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 ...

  12. 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...

  13. Recognizing Neglected Strengths

    ERIC Educational Resources Information Center

    Sternberg, Robert J.

    2006-01-01

    To identify diverse student strengths and to learn how teachers can build instruction on those strengths, the author and his colleagues have conducted multiple studies among students in Alaska, the mainland United States, Kenya, and other countries. In a series of studies in Alaska and Kenya, the researchers measured the adaptive cultural…

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

    NASA Astrophysics Data System (ADS)

    Lang, Murong; He, Liang; Kou, Xufeng; Upadhyaya, Pramey; Fan, Yabin; Chu, Hao; Yeh, Nai-Chang; Wang, Kang

    2013-03-01

    We demonstrate the evidences of a surface gap opening in (Bi0.57Sb0.43)2 Te3 samples for film thickness below 6 quintuple layers, through magnetotransport and scanning tunneling spectroscopy measurements. By tuning Fermi level position relative to the gap, the striking crossover between weak antilocalization and weak localization is observed in nonmagnetic 4 and 5 QL films at low field region, a characteristic feature of quantum interferences competition, possibly owing to the change of net Berry phase. Furthermore, when the Fermi level is swept into the surface gap, the overall unitary behaviors are revealed at higher magnetic field, which are in contrast to the pure WAL signals obtained in thicker films. Besides, the surface bandgap of ultrathin film is also determined by low temperature STS measurements. 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. This work was in part supported by Defense Advanced Research Projects Agency (DARPA), Focus Center Research Program-Center on Functional Engineered Nano Architectonics (FENA).

  15. Relaxion monodromy and the Weak Gravity Conjecture

    NASA Astrophysics Data System (ADS)

    Ibáñez, L. E.; Montero, M.; Uranga, A. M.; Valenzuela, I.

    2016-04-01

    The recently proposed relaxion models require extremely large trans-Planckian axion excursions as well as a potential explicitly violating the axion shift symmetry. The latter property is however inconsistent with the axion periodicity, which corresponds to a gauged discrete shift symmetry. A way to make things consistent is to use monodromy, i.e. both the axion and the potential parameters transform under the discrete shift symmetry. The structure is better described in terms of a 3-form field C μνρ coupling to the SM Higgs through its field strength F 4. The 4-form also couples linearly to the relaxion, in the Kaloper-Sorbo fashion. The extremely small relaxion-Higgs coupling arises in a see-saw fashion as g ≃ F 4 /f , with f being the axion decay constant. We discuss constraints on this type of constructions from membrane nucleation and the Weak Gravity Conjecture. The latter requires the existence of membranes, whose too fast nucleation could in principle drive the theory out of control, unless the cut-off scale is lowered. This allows to rule out the simplest models with the QCD axion as relaxion candidate on purely theoretical grounds. We also discuss possible avenues to embed this structure into string theory.

  16. Constraints on neutrino masses from weak lensing

    SciTech Connect

    Ichiki, Kiyotomo; Takada, Masahiro; Takahashi, Tomo

    2009-01-15

    Weak lensing (WL) distortions of distant galaxy images are sensitive to neutrino masses by probing the suppression effect on clustering strengths of total matter in large-scale structure. We use the latest measurements of WL correlations, the Canada-France-Hawaii Telescope Legacy Survey data, to explore constraints on neutrino masses. We find that, while the WL data alone cannot place a stringent limit on neutrino masses due to parameter degeneracies, the constraint can be significantly improved when combined with other cosmological probes, such as the WMAP 5-year data (WMAP5) and the distance measurements of type-Ia supernovae (SNe) and baryon acoustic oscillations (BAO). The upper bounds on the sum of neutrino masses are , 0.76, and 0.54 eV (95% CL) for WL+WMAP5, WMAP5+SNe+BAO, and WL+WMAP5+SNe+BAO, respectively, assuming a flat {lambda}CDM model with finite-mass neutrinos. In deriving these constraints, our analysis includes the non-Gaussian covariances of the WL correlation functions to properly take into account significant correlations between different angles.

  17. 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.

  18. 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".

  19. 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.

  20. 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.

  1. Electromagnetic weak turbulence theory revisited

    SciTech Connect

    Yoon, P. H.; Ziebell, L. F.; Gaelzer, R.; Pavan, J.

    2012-10-15

    The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

  2. 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

  3. Charge on a weak polyelectrolyte

    NASA Astrophysics Data System (ADS)

    Wang, Shengqin; Granick, Steve; Zhao, Jiang

    2008-12-01

    Fluorescence measurements with single-molecule sensitivity are used to measure the hydrodynamic size and local pH of a weak polyelectrolyte, poly-2-vinyl pyridine end labeled with pH-sensitive dye, the polyelectrolyte having concentration so low (nanomolars) that molecular properties are resolvable only from fluorescence experiments and cannot be accessed by light scattering. We find that the local pH near the dye, inferred from its brightness, is consistently three orders of magnitude higher than the bulk pH. Upon varying the bulk pH, we measure the collapse point at which hydrophobic attraction overwhelms electrostatic repulsion between charged elements along the chain, and conclude that adding monovalent salt shifts this coil-to-globule collapse to higher pH than in the absence of salt. The influence of salt appears to shift the ionization equilibrium of this weak polyelectrolyte in the direction of the chain possessing enhanced electric charge at a given pH. Phenomenologically, this is opposite to the case for strong polyelectrolytes, although the mechanism differs.

  4. 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.

  5. 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.

  6. 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.

  7. Weak measurement and quantum steering of spin qubits in silicon

    NASA Astrophysics Data System (ADS)

    Morello, Andrea; Muhonen, Juha; Simmons, Stephanie; Freer, Solomon; Dehollain, Juan; McCallum, Jeffrey; Jamieson, David; Itoh, Kohei; Dzurak, Andrew

    Single-shot, projective measurements have been demonstrated with very high fidelities on both the electron and the nuclear spin of single implanted phosphorus (31P) donors in silicon. Here we present a series of experiments where the measurement strength is continousuly reduced, giving access to the regime of weak measurement of single spins.For the electron qubit, the measurement strength is set by the measurement time compared to the spin-dependent tunneling time between the 31P donor and a charge reservoir. For the nuclear qubit, the measurement strength is set by the rotation angle of an ESR pulse.We have demonstrated quantum steering of the spin states, with curious and useful applications. We can improve the fidelity of electron qubit initialization by steering it towards the ground state, thus bypassing thermal effects on the initialization process. We can also accurately measure the electron-reservoir tunnel coupling, without the electron ever tunneling away from the 31P atom. Finally, these techniques allow the study of weak values and Leggett-Garg inequalities. Present address: AMOLF, Amsterdam, The Netherlands.

  8. 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.

  9. 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...

  10. Reduction of bone strength

    NASA Technical Reports Server (NTRS)

    Bingham, Cindy

    1990-01-01

    Viewgraphs on reduction of bone strength are presented. WEHI 231 B growth rates, experimental chambers used to apply the electric field to the cell cultures, and a mouse suspended by rotating cuff in electromagnetic field are shown.

  11. 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)

  12. The Computational Complexity of Weak Saddles

    NASA Astrophysics Data System (ADS)

    Brandt, Felix; Brill, Markus; Fischer, Felix; Hoffmann, Jan

    We continue the recently initiated study of the computational aspects of weak saddles, an ordinal set-valued solution concept proposed by Shapley. Brandt et al. gave a polynomial-time algorithm for computing weak saddles in a subclass of matrix games, and showed that certain problems associated with weak saddles of bimatrix games are NP-complete. The important question of whether weak saddles can be found efficiently was left open. We answer this question in the negative by showing that finding weak saddles of bimatrix games is NP-hard, under polynomial-time Turing reductions. We moreover prove that recognizing weak saddles is coNP-complete, and that deciding whether a given action is contained in some weak saddle is hard for parallel access to NP and thus not even in NP unless the polynomial hierarchy collapses. Our hardness results are finally shown to carry over to a natural weakening of weak saddles.

  13. 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

  14. 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. PMID:23703222

  15. Weakly ionized cerium plasma radiography

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Hayasi, Yasuomi; Germer, Rudolf; Koorikawa, Yoshitake; Murakami, Kazunori; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Ichimaru, Toshio; Obata, Fumiko; Takahashi, Kiyomi; Sato, Sigehiro; Takayama, Kazuyoshi; Ido, Hideaki

    2004-02-01

    In the plasma flash x-ray generator, high-voltage main condenser of about 200 nF is charged up to 55 kV by a power supply, and electric charges in the condenser are discharged to an x-ray tube after triggering the cathode electrode. The flash x-rays are then produced. The x-ray tube is of a demountable triode that is connected to a turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to a rod cerium target of 3.0 mm in diameter by electric field in the x-ray tube, the weakly ionized linear plasma, which consists of cerium ions and electrons, forms by target evaporating. At a charging voltage of 55 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 20 kA. When the charging voltage was increased, weakly ionized cerium plasma formed, and the K-series characteristic x-ray intensities increased. The x-ray pulse widths were about 500 ns, and the time-integrated x-ray intensity had a value of about 40 μC/kg at 1.0 m from x-ray source with a charging voltage of 55 kV. In the angiography, we employed a film-less computed radiography (CR) system and iodine-based microspheres. Because K-series characteristic x-rays are absorbed easily by the microspheres, high-contrast angiography has been performed.

  16. Statistical theory of electromagnetic weak turbulence

    SciTech Connect

    Yoon, Peter H.

    2006-02-15

    The weak turbulence theory as commonly found in the literature employs electrostatic approximation and is applicable to unmagnetized plasmas only. To this date, fully electromagnetic generalization of the existing weak turbulence theory based upon statistical mechanical approach remains largely incomplete. Instead, electromagnetic effects are incorporated into the weak turbulence formalism by means of the semiclassical approach. The present paper reformulates the fully electromagnetic weak turbulence theory from classical statistical mechanical (i.e., the Klimontovich) approach.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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. PMID:26424883

  5. 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.

  6. Weak percolation on multiplex networks.

    PubMed

    Baxter, Gareth J; Dorogovtsev, Sergey N; Mendes, José F F; Cellai, Davide

    2014-04-01

    Bootstrap percolation is a simple but nontrivial model. It has applications in many areas of science and has been explored on random networks for several decades. In single-layer (simplex) networks, it has been recently observed that bootstrap percolation, which is defined as an incremental process, can be seen as the opposite of pruning percolation, where nodes are removed according to a connectivity rule. Here we propose models of both bootstrap and pruning percolation for multiplex networks. We collectively refer to these two models with the concept of "weak" percolation, to distinguish them from the somewhat classical concept of ordinary ("strong") percolation. While the two models coincide in simplex networks, we show that they decouple when considering multiplexes, giving rise to a wealth of critical phenomena. Our bootstrap model constitutes the simplest example of a contagion process on a multiplex network and has potential applications in critical infrastructure recovery and information security. Moreover, we show that our pruning percolation model may provide a way to diagnose missing layers in a multiplex network. Finally, our analytical approach allows us to calculate critical behavior and characterize critical clusters. PMID:24827287

  7. Weakly Supervised Human Fixations Prediction.

    PubMed

    Zhang, Luming; Li, Xuelong; Nie, Liqiang; Yang, Yi; Xia, Yingjie

    2016-01-01

    Automatically predicting human eye fixations is a useful technique that can facilitate many multimedia applications, e.g., image retrieval, action recognition, and photo retargeting. Conventional approaches are frustrated by two drawbacks. First, psychophysical experiments show that an object-level interpretation of scenes influences eye movements significantly. Most of the existing saliency models rely on object detectors, and therefore, only a few prespecified categories can be discovered. Second, the relative displacement of objects influences their saliency remarkably, but current models cannot describe them explicitly. To solve these problems, this paper proposes weakly supervised fixations prediction, which leverages image labels to improve accuracy of human fixations prediction. The proposed model hierarchically discovers objects as well as their spatial configurations. Starting from the raw image pixels, we sample superpixels in an image, thereby seamless object descriptors termed object-level graphlets (oGLs) are generated by random walking on the superpixel mosaic. Then, a manifold embedding algorithm is proposed to encode image labels into oGLs, and the response map of each prespecified object is computed accordingly. On the basis of the object-level response map, we propose spatial-level graphlets (sGLs) to model the relative positions among objects. Afterward, eye tracking data is employed to integrate these sGLs for predicting human eye fixations. Thorough experiment results demonstrate the advantage of the proposed method over the state-of-the-art. PMID:26168451

  8. 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.

  9. Weak percolation on multiplex networks

    NASA Astrophysics Data System (ADS)

    Baxter, Gareth J.; Dorogovtsev, Sergey N.; Mendes, José F. F.; Cellai, Davide

    2014-04-01

    Bootstrap percolation is a simple but nontrivial model. It has applications in many areas of science and has been explored on random networks for several decades. In single-layer (simplex) networks, it has been recently observed that bootstrap percolation, which is defined as an incremental process, can be seen as the opposite of pruning percolation, where nodes are removed according to a connectivity rule. Here we propose models of both bootstrap and pruning percolation for multiplex networks. We collectively refer to these two models with the concept of "weak" percolation, to distinguish them from the somewhat classical concept of ordinary ("strong") percolation. While the two models coincide in simplex networks, we show that they decouple when considering multiplexes, giving rise to a wealth of critical phenomena. Our bootstrap model constitutes the simplest example of a contagion process on a multiplex network and has potential applications in critical infrastructure recovery and information security. Moreover, we show that our pruning percolation model may provide a way to diagnose missing layers in a multiplex network. Finally, our analytical approach allows us to calculate critical behavior and characterize critical clusters.

  10. Elasticity and Strength of Biomacromolecular Crystals: Lysozyme

    NASA Technical Reports Server (NTRS)

    Holmes, A. M.; Witherow, W. K.; Chen, L. Q.; Chernov, A. A.

    2003-01-01

    The static Young modulus, E = 0.1 to 0.5 GPa, the crystal critical strength (sigma(sub c)) and its ratio to E,sigma(sub c)/E is approximately 10(exp 3), were measured for the first time for non cross-linked lysozyme crystals in solution. By using a triple point bending apparatus, we also demonstrated that the crystals were purely elastic. Softness of protein crystals built of hard macromolecules (26 GPa for lysozyme) is explained by the large size of the macromolecules as compared to the range of intermolecular forces and by the weakness of intermolecular bonds as compared to the peptide bond strength. The relatively large reported dynamic elastic moduli (approximately 8 GPa) from resonance light scattering should come from averaging over the moduli of intracrystalline water and intra- and intermolecular bonding.

  11. 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.

  12. Strength of inorganic glass

    SciTech Connect

    Kurkjian, C.R.

    1985-01-01

    This book presents information on the following topics: a look at the history of glass strength; atomistic theory of fracture; surface chemistry in relation to the strength and fracture of silicate glasses; high-speed photographic investigations of the dynamic localized loading of some oxide glasses; a correction for measurements of contact area using Newton's rings; envionmentally enhanced crack growth; fatigue in glass; behavior of flaws in fused silica fibers; fracture toughness of chalcogenide glasses and glass-ceramics; fracture analysis of glass surfaces; and fracture mechanics parameters for glasses - a compilation and correlation.

  13. High strength alloys

    SciTech Connect

    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.

  14. High strength alloys

    SciTech Connect

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

    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.

  15. 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

  16. 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

  17. Pixelation Effects in Weak Lensing

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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, and 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. 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

  20. 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.

  1. 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.

  2. 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

  3. Crossover between strong and weak measurement in interacting many-body systems

    NASA Astrophysics Data System (ADS)

    Esin, Iliya; Romito, Alessandro; Blanter, Ya M.; Gefen, Yuval

    2016-01-01

    Measurements with variable system-detector interaction strength, ranging from weak to strong, have been recently reported in a number of electronic nanosystems. In several such instances many-body effects play a significant role. Here we consider the weak-to-strong crossover for a setup consisting of an electronic Mach-Zehnder interferometer, where a second interferometer is employed as a detector. In the context of a conditional which-path protocol, we define a generalized conditional value (GCV), and determine its full crossover between the regimes of weak and strong (projective) measurement. We find that the GCV has an oscillatory dependence on the system-detector interaction strength. These oscillations are a genuine many-body effect, and can be experimentally observed through the voltage dependence of cross current correlations.

  4. 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

  5. Evidence-based alcohol policy in the Americas: strengths, weaknesses, and future challenges.

    PubMed

    Babor, Thomas F; Caetano, Raul

    2005-01-01

    The objectives of this article are to describe the evidence base for alcohol policy in the Americas, to evaluate the extent to which national policies are likely to have an impact on public health, and to identify areas where alcohol policies could be improved. The paper begins with a brief review of epidemiological surveys of the prevalence of alcohol problems in the Americas. This is followed by an analysis of 32 prevention strategies and interventions in terms of the evidence for their effectiveness, amount of research support, cost to implement, and other feasibility issues. Overall, the strategies and interventions with the greatest amount of empirical support are low blood alcohol concentration levels for driving while intoxicated, controls on alcohol availability, age limits on alcohol purchases, and relatively high alcohol prices. The implications of the evidence are next discussed in relation to alcohol policy initiatives in the Americas, based on an analysis of the extent to which strategies and interventions currently used in 25 countries of the Americas are likely to have a public health impact on alcohol-related problems. The countries that have adopted the policies with the highest expected impact overall are Colombia, Costa Rica, Venezuela, and El Salvador. Nevertheless, the analysis indicates that almost all the countries of the Americas could improve the likelihood of preventing alcohol-related problems. Policy efforts in the developing countries of Latin America should focus on improving countermeasures against driving while intoxicated, measures that alter the drinking context, and limits on physical availability. For the developed, high-income countries of North America the goal should be to prevent deterioration of current drinking patterns and to reduce the overall volume of drinking. Given the low to moderate cost of many of the policies reviewed in this article, it now seems possible for communities and nations to substantially reduce the alcohol-related burden of illness in the Americas. PMID:16354430

  6. The U-Ti system: Strengths and weaknesses of the CALPHAD method

    NASA Astrophysics Data System (ADS)

    Bajaj, Saurabh; Landa, Alexander; Söderlind, Per; Turchi, Patrice E. A.; Arróyave, Raymundo

    2011-12-01

    Input from Density Functional Theory (DFT) calculations is used to understand phase equilibria in a binary metallic alloy fuel system: U-Ti. The CALPHAD approach is employed to calculate a U-Ti phase diagram that is consistent not only with experimental data but also—more importantly—with thermodynamic data from DFT calculations: heat of formation of γ(bcc)-U-Ti alloys as a function of composition, and formation enthalpy of the δ-U 2Ti compound. Three DFT-based electronic structure methods are utilized: SR-KKR-ASA-CPA, SR-EMTO-CPA, and FPLMTO-SQS, and the use of derived ab initio data avoids the manifestation of unreasonable or inaccurate phase stabilities that result from an otherwise unconstrained Gibbs energy minimization within the CALPHAD approach. We also investigate phase formation of the δ-U 2Ti phase in the U-Ti system, that stabilizes in the same C32 structure as other binary metallic fuel alloys such as U-Zr and Np-Zr.

  7. 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…

  8. 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…

  9. Profiling Fragile X Syndrome in Males: Strengths and Weaknesses in Cognitive Abilities

    ERIC Educational Resources Information Center

    Van der Molen, M. J. W.; Huizinga, M.; Huizenga, H. M.; Ridderinkhof, K. R.; Van der Molen, M. W.; Hamel, B. J. C.; Curfs, L. M. G.; Ramakers, G. J. A.

    2010-01-01

    The present study examined the cognitive profile in Fragile X Syndrome (FXS) males, and investigated whether cognitive profiles are similar for FXS males at different levels of intellectual functioning. Cognitive abilities in non-verbal, verbal, memory and executive functioning domains were contrasted to both a non-verbal and verbal mental age…

  10. White paper of Italian Gastroenterology: delivery of services for digestive diseases in Italy: weaknesses and strengths.

    PubMed

    Buscarini, Elisabetta; Conte, Dario; Cannizzaro, Renato; Bazzoli, Franco; De Boni, Michele; Delle Fave, Gianfranco; Farinati, Fabio; Ravelli, Paolo; Testoni, Pier Alberto; Lisiero, Manola; Spolaore, Paolo

    2014-07-01

    In 2011 the three major Italian gastroenterological scientific societies (AIGO, the Italian Society of Hospital Gastroenterologists and Endoscopists; SIED, the Italian Society of Endoscopy; SIGE, the Italian Society of Gastroenterology) prepared their official document aimed at analysing medical care for digestive diseases in Italy, on the basis of national and regional data (Health Ministry and Lombardia, Veneto, Emilia-Romagna databases) and to make proposals for planning of care. Digestive diseases were the first or second cause of hospitalizations in Italy in 1999-2009, with more than 1,500,000 admissions/year; however only 5-9% of these admissions was in specialized Gastroenterology units. Reported data show a better outcome in Gastroenterology Units than in non-specialized units: shorter average length of stay, in particular for admissions with ICD-9-CM codes proxying for emergency conditions (6.7 days versus 8.4 days); better case mix (higher average diagnosis-related groups weight in Gastroenterology Units: 1 vs 0.97 in Internal Medicine units and 0.76 in Surgery units); lower inappropriateness of admissions (16-25% versus 29-87%); lower in-hospital mortality in urgent admissions (2.2% versus 5.1%); for patients with urgent admissions due to gastrointestinnal haemorrhage, in-hospital mortality was 2.3% in Gastroenterology units versus 4.0% in others. The present document summarizes the scientific societies' official report, which constitutes the "White paper of Italian Gastroenterology". PMID:24913902

  11. 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

  12. 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…

  13. 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…

  14. 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…

  15. 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

  16. 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…

  17. 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

  18. 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,…

  19. Quality Details: A Close-Up Look at Child Care Program Strengths and Weaknesses.

    ERIC Educational Resources Information Center

    Cryer, Debby; Phillipsen, Leslie

    1997-01-01

    Examined quality of infant/toddler and preschool child care centers. Found that although overall program quality was mediocre at best, accredited programs scored better than nonaccredited programs. Preschool classrooms needed improvements in cultural awareness, child privacy, and furnishings for relaxation. For infant/toddler programs,…

  20. Ischemic optic neuropathies and their models: disease comparisons, model strengths and weaknesses

    PubMed Central

    Miller, Neil R.

    2015-01-01

    Ischemic optic neuropathies (IONs) describe a group of diseases that specifically target the optic nerve and result in sudden vision loss. These include nonarteritic and arteritic anterior ischemic optic neuropathy (NAION and AAION) and posterior ischemic optic neuropathy (NPION, APION). Until recently, little was known of the mechanisms involved in ION damage, due to a lack of information about the mechanisms associated with these diseases. This review discusses the new models that closely mimic these diseases (rodent NAION, primate NAION, rodent PION). These models have enabled closer dissection of the mechanisms involved with the pathophysiology of these disorders and enable identification of relevant mechanisms and potential pathways for effective therapeutic intervention. Descriptions of the different models are included, and comparisons between the models, their relative similarities with the clinical disease, as well as differences are discussed. PMID:25690987

  1. 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…

  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. PMID:25468688

  3. A Preliminary Screening Program to Identify Functioning Strengths and Weaknesses in Preschool Children.

    ERIC Educational Resources Information Center

    Amundson, Marian Stuehrenberg

    The purpose of this study was to compare two instruments for screening preschool children for potential learning problems. The two instruments used were the Metropolitan Readiness Tests (MRT) and the Wizard of Oz Preschool Preliminary Screening Program. The children tested on both measures were members of a self-contained kindergarten class. MRT…

  4. 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…

  5. 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.

  6. STRENGTHS AND WEAKNESSES OF MOLECULAR MARKERS FOR STUDIES OF DIVERSITY IN GENEBANK HOLDINGS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular markers have many potential advantages over morphological or other marker types to characterize within- and between-species diversity, useful for management of genebank holdings. These include greater number (potentially unlimited) of markers, freedom from pleiotropic effects, greater ease...

  7. Progression or Regression? – Strengths and Weaknesses of the New Munich Nomenclature III for Cervix Cytology

    PubMed Central

    Hilal, Z.; Tempfer, C.; Schiermeier, S.; Reinecke, J.; Ruppenkamp, C.; Hilal, Z.

    2015-01-01

    Introduction: Since 01. 01. 2015 the new Munich nomenclature III for gynaecological diagnostics of the cervix has been in force. The changes have led to controversial scientific discussions. This study reports for the first time on the consequences. Materials and Methods: The present data are based on smear screening results for the year 2014. The data of 63 134 patients were evaluated. Results: 2.27 % of all smears were remarkable. Group IIa was assigned to 0.91 %. Group II-p was somewhat more frequently recorded than group IIID1 (0.59 vs. 0.53 %). Groups IIID1 and IIID2 were found in 0.53 and 0.61 %, respectively, of the cases. Agreement with histology was found in 36.84 and 44.68 %, respectively. Glandular lesions represented the most frequent changes in group III. Histological clarification was obtained for 0.18 % of all remarkable findings. The relative incidence of high-grade precancerous conditions (CIN III) and invasive tumours amounted to 0.1 %. Conclusion: A close communication between gynaecologists and cytologists is mandatory for the correct usage of the new nomenclature. The future annual statistics of the health insurances can now be analysed in more detail. A statistical classification of glandular epithelial changes is now also possible for the first time. The heterogeneous group IIa constitutes an unnecessary uncertainty for patients and physicians. The splitting of the group IIID does not appear to have any advantage for the further clinical management. Further studies are needed to show whether or not the classification can stand up to international comparisons. PMID:26556907

  8. 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…

  9. 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

  10. Strengths, weaknesses, opportunities and challenges for long acting injectable therapies: Insights for applications in HIV therapy.

    PubMed

    Owen, Andrew; Rannard, Steve

    2016-08-01

    Advances in solid drug nanoparticle technologies have resulted in a number of long-acting (LA) formulations with the potential for once monthly or longer administration. Such formulations offer great utility for chronic diseases, particularly when a lack of medication compliance may be detrimental to treatment response. Two such formulations are in clinical development for HIV but the concept of LA delivery has its origins in indications such as schizophrenia and contraception. Many terms have been utilised to describe the LA approach and standardisation would be beneficial. Ultimately, definitions will depend upon specific indications and routes of delivery, but for HIV we propose benchmarks that reflect perceived clinical benefits and available data on patient attitudes. Specifically, we propose dosing intervals of ≥1week, ≥1month or ≥6months, for oral, injectable or implantable strategies, respectively. This review focuses upon the critical importance of potency in achieving the LA outcome for injectable formulations and explores established and emerging technologies that have been employed across indications. Key technological challenges such as the need for consistency and ease of administration for drug combinations, are also discussed. Finally, the review explores the gaps in knowledge regarding the pharmacology of drug release from particulate-based LA injectable suspensions. A number of hypotheses are discussed based upon available data relating to local drug metabolism, active transport systems, the lymphatics, macrophages and patient-specific factors. Greater knowledge of the mechanisms that underpin drug release and protracted exposure will help facilitate further development of this strategy to achieve the promising clinical benefits. PMID:26916628

  11. The Bookmark Procedure for Setting Cut-Scores and Finalizing Performance Standards: Strengths and Weaknesses

    ERIC Educational Resources Information Center

    Lin, Jie

    2006-01-01

    The Bookmark standard-setting procedure was developed to address the perceived problems with the most popular method for setting cut-scores: the Angoff procedure (Angoff, 1971). The purposes of this article are to review the Bookmark procedure and evaluate it in terms of Berk's (1986) criteria for evaluating cut-score setting methods. The…

  12. 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…

  13. [EpiInfo as a research and teaching tool in epidemiology and statistics: strengths and weaknesses].

    PubMed

    Mannocci, Alice; Bontempi, Claudio; Giraldi, Guglielmo; Chiaradia, Giacomina; de Waure, Chiara; Sferrazza, Antonella; Ricciardi, Walter; Boccia, Antonio; La Torre, Giuseppe

    2012-01-01

    EpiInfo is a free software developed in 1988 by the Centers for Disease Control and Prevention (CDC) in Atlanta to facilitate field epidemiological investigations and statistical analysis. The aim of this study was to assess whether the software represents, in the Italian biomedical field, an effective analytical research tool and a practical and simple epidemiology and biostatistics teaching tool. A questionnaire consisting of 20 multiple-choice and open questions was administered to 300 healthcare workers, including doctors, biologists, nurses, medical students and interns, at the end of a CME course in epidemiology and biostatistics. Sixty-four percent of participants were aged between 26 and 45 years, 52% were women and 73% were unmarried. Results show that women are more likely to utilize EpiInfo in their research activities with respect to men (p = 0.023), as are individuals aged 26-45 years with respect to the older and younger age groups (p = 0.023) and unmarried participants with respect to those married (p = 0.010). Thirty-one percent of respondents consider EpiInfo to be more than adequate for analysis of their research data and 52% consider it to be sufficiently so. The inclusion of an EpiInfo course in statistics and epidemiology modules facilitates the understanding of theoretical concepts and allows researchers to more easily perform some of the clinical/epidemiological research activities. PMID:22507994

  14. Strengths-based nursing.

    PubMed

    Gottlieb, Laurie N

    2014-08-01

    Strengths-based nursing (SBN) is an approach to care in which eight core values guide nursing action, thereby promoting empowerment, self-efficacy, and hope. In caring for patients and families, the nurse focuses on their inner and outer strengths-that is, on what patients and families do that best helps them deal with problems and minimize deficits. Across all levels of care, from the primary care of healthy patients to the critical care of patients who are unconscious, SBN reaffirms nursing's goals of promoting health, facilitating healing, and alleviating suffering by creating environments that work with and bolster patients' capacities for health and innate mechanisms of healing. In doing so, SBN complements medical care, provides a language that communicates nursing's contribution to patient and family health and healing, and empowers the patient and family to gain greater control over their health and healing. PMID:25036663

  15. Strength cues and blocking at test promote reliable within-list criterion shifts in recognition memory.

    PubMed

    Hicks, Jason L; Starns, Jeffrey J

    2014-07-01

    In seven experiments, we explored the potential for strength-based, within-list criterion shifts in recognition memory. People studied a mix of target words, some presented four times (strong) and others studied once (weak). In Experiments 1, 2, 4A, and 4B, the test was organized into alternating blocks of 10, 20, or 40 trials. Each block contained lures intermixed with strong targets only or weak targets only. In strength-cued conditions, test probes appeared in a unique font color for strong and weak blocks. In the uncued conditions of Experiments 1 and 2, similar strength blocks were tested, but strength was not cued with font color. False alarms to lures were lower in blocks containing strong target words, as compared with lures in blocks containing weak targets, but only when strength was cued with font color. Providing test feedback in Experiment 2 did not alter these results. In Experiments 3A-3C, test items were presented in a random order (i.e., not blocked by strength). Of these three experiments, only one demonstrated a significant shift even though strength cues were provided. Overall, the criterion shift was larger and more reliable as block size increased, and the shift occurred only when strength was cued with font color. These results clarify the factors that affect participants' willingness to change their response criterion within a test list. PMID:24523046

  16. 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.

  17. Bone strength: current concepts.

    PubMed

    Turner, Charles H

    2006-04-01

    Bones serve several mechanical functions, including acoustic amplification in the middle ear, shielding vital organs from trauma, and serving as levers for muscles to contract against. Bone is a multiphase material made up of a tough collagenous matrix intermingled with rigid mineral crystals. The mineral gives bone its stiffness. Without sufficient mineralization, bones will plastically deform under load. Collagen provides toughness to bone making it less brittle so that it better resists fracture. Bone adapts to mechanical stresses largely by changing its size and shape, which are major determinants of its resistance to fracture. Tissue is added in regions of high mechanical stress providing an efficient means for improving bone strength. Experiments have shown that small additions of bone mineral density (BMD) (5-8%) caused by mechanical loading can improve bone strength by over 60% and extend bone fatigue life by 100-fold. Consequently, it is clear that bone tissue possesses a mechanosensing apparatus that directs osteogenesis to where it is most needed for improving bone strength. The biological processes involved in bone mechanotransduction are poorly understood and further investigation of the molecular mechanisms involved might uncover drug targets for osteoporosis. Several pathways are emerging from current research, including membrane ion channels, ATP signaling, second messengers, such as prostaglandins and nitric oxide, insulin-like growth factors, and Wnt signaling. PMID:16831941

  18. 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.

  19. On modeling weak sinks in MODPATH.

    PubMed

    Abrams, Daniel; Haitjema, H; Kauffman, L

    2013-01-01

    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. PMID:23025655

  20. 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.

  1. 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.

  2. Weak Interactions of Hot Nuclei in Stellar Collapse

    NASA Astrophysics Data System (ADS)

    Misch, Gordon Wendell

    The physics of the atomic nucleus and supernovas are fundamental to our very being. Indeed, supernovas provide the wind that disperses the nuclei of which we are composed, and the physics of nuclei is pivotal in supernova dynamics. During supernova core collapse, the extremely high temperatures and densities and low entropy favor large, neutron-rich nuclei at high excitation energy. My collaborators and I examine two weak interactions that occur in nuclei under these conditions. First, we study the production of neutrino pairs via de-excitation of hot nuclei. In de-exciting, the nucleus can emit a virtual Z0 boson that decays into a neutrino-antineutrino pair. We find this to be the dominant source of neutrino pairs of all flavors during collapse. Second, we use modern shell model computation techniques to revise the Brink-Axel hypothesis method of computing electron capture rates that was pioneered by Fuller, Fowler, and Newman. Our results show that the Brink-Axel hypothesis (which posits that the bulk of nuclear transition strength is distributed among transition energies independently of initial excitation energy) fails at low and moderate excitation, but that at high initial energies, the strength is largely independent of excitation. The failure of the Brink-Axel hypothesis manifests as the redistribution of strength to low and negative transition energies, which can have the effect of increasing the overall electron capture rate in the core.

  3. Structure of Weak Shock Waves in a Monatomic Gas

    NASA Technical Reports Server (NTRS)

    Sherman, F. S.; Talbot, L.

    1959-01-01

    The profiles and thicknesses of normal shock waves in argon at Mach numbers of 1.335, 1.454, 1.576, and 1-713 were determined experimentally by means of a free-molecule probe whose equilibrium temperature is related by kinetic theory to the local flow properties and their gradients. Comparisons were made between the experimental shock profiles and the theoretical profiles calculated from the Navier-Stokes equations, the Grad 13-moment equations, and the Burnett equations. New, very accurate numerical integrations of the Burnett equations were obtained for this purpose with results quite different from those found by Zoller, to whom the solution of this problem is frequently attributed. The experimental shock profiles were predicted with approximately equal success by the Navier-Stokes and Burnett theories, while the 13-moment method was definitely less satisfactory. A surprising feature of the theoretical results is the relatively small difference in predictions between the Navier-Stokes and Burnett theories in the present range of shock strengths and the contrastingly large difference between predictions of Burnett and the 13-moment theories. It is concluded that the Navier-Stokes equations are correct for weak shocks and that within the present shock strength range the Burnett equations make no improvement which merits the trouble of solving them. For shocks of noticeably greater strength, say with a shock Mach number of more than 2.5, it remains fundamentally doubtful that any of these theories can be correct.

  4. Maximal Holevo Quantity Based on Weak Measurements

    PubMed Central

    Wang, Yao-Kun; Fei, Shao-Ming; Wang, Zhi-Xi; Cao, Jun-Peng; Fan, Heng

    2015-01-01

    The Holevo bound is a keystone in many applications of quantum information theory. We propose “ maximal Holevo quantity for weak measurements” as the generalization of the maximal Holevo quantity which is defined by the optimal projective measurements. The scenarios that weak measurements is necessary are that only the weak measurements can be performed because for example the system is macroscopic or that one intentionally tries to do so such that the disturbance on the measured system can be controlled for example in quantum key distribution protocols. We evaluate systematically the maximal Holevo quantity for weak measurements for Bell-diagonal states and find a series of results. Furthermore, we find that weak measurements can be realized by noise and project measurements. PMID:26090962

  5. Identical Quantum Particles and Weak Discernibility

    NASA Astrophysics Data System (ADS)

    Dieks, Dennis; Versteegh, Marijn A. M.

    2008-10-01

    Saunders has recently claimed that “identical quantum particles” with an anti-symmetric state (fermions) are weakly discernible objects, just like irreflexively related ordinary objects in situations with perfect symmetry (Black’s spheres, for example). Weakly discernible objects have all their qualitative properties in common but nevertheless differ from each other by virtue of (a generalized version of) Leibniz’s principle, since they stand in relations an entity cannot have to itself. This notion of weak discernibility has been criticized as question begging, but we defend and accept it for classical cases likes Black’s spheres. We argue, however, that the quantum mechanical case is different. Here the application of the notion of weak discernibility indeed is question begging and in conflict with standard interpretational ideas. We conclude that the introduction of the conceptual resource of weak discernibility does not change the interpretational status quo in quantum mechanics.

  6. Persisting weakness after withdrawal of a statin.

    PubMed

    Mygland, Åse; Ljøstad, Unn; Krossnes, Bård Kronen

    2014-01-01

    An 81-year-old woman treated with simvastatin for several years followed by atorvastatin for about 1 year presented with fatigue, weakness and unsteady gait. The finding of elevated creatine kinase (CK) and symmetric muscle weakness around shoulders and hips led to suspicion of a toxic statin-associated myopathy. Atorvastatin was withdrawn, but her weakness persisted. Owing to persisting weakness, an autoimmune myopathy (myositis) was suspected, but initially disregarded since a muscle biopsy showed necrotic muscle fibres without inflammatory cell infiltrates and myositis-specific autoantibodies were absent. After 18 months with slowly progressive weakness and increasing CK values, awareness of new knowledge about autoimmunity as a cause of necrotic myopathy, led to a successful treatment trial with intravenous immunoglobulines, followed by steroids and metothrexate. Antibodies to the target enzyme of statins (HMGCR (3-hydroksy-3-methylglutaryl-coenzyme A reductase)) were detected in her serum, and she was diagnosed with autoimmune necrotic myositis probably triggered by atorvastatin. PMID:24713712

  7. 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.

  8. 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.

  9. The value of multiple tests of respiratory muscle strength

    PubMed Central

    Steier, Joerg; Kaul, Sunny; Seymour, John; Jolley, Caroline; Rafferty, Gerrard; Man, William; Luo, Yuan M; Roughton, Michael; Polkey, Michael I; Moxham, John

    2007-01-01

    Background Respiratory muscle weakness is an important clinical problem. Tests of varying complexity and invasiveness are available to assess respiratory muscle strength. The relative precision of different tests in the detection of weakness is less clear, as is the value of multiple tests. Methods The respiratory muscle function tests of clinical referrals who had multiple tests assessed in our laboratories over a 6‐year period were analysed. Thresholds for weakness for each test were determined from published and in‐house laboratory data. The patients were divided into three groups: those who had all relevant measurements of global inspiratory muscle strength (group A, n = 182), those with full assessment of diaphragm strength (group B, n = 264) and those for whom expiratory muscle strength was fully evaluated (group C, n = 60). The diagnostic outcome of each inspiratory, diaphragm and expiratory muscle test, both singly and in combination, was studied and the impact of using more than one test to detect weakness was calculated. Results The clinical referrals were primarily for the evaluation of neuromuscular diseases and dyspnoea of unknown cause. A low maximal inspiratory mouth pressure (Pimax) was recorded in 40.1% of referrals in group A, while a low sniff nasal pressure (Sniff Pnasal) was recorded in 41.8% and a low sniff oesophageal pressure (Sniff Poes) in 37.9%. When assessing inspiratory strength with the combination of all three tests, 29.6% of patients had weakness. Using the two non‐invasive tests (Pimax and Sniff Pnasal) in combination, a similar result was obtained (low in 32.4%). Combining Sniff Pdi (low in 68.2%) and Twitch Pdi (low in 67.4%) reduced the diagnoses of patients with diaphragm weakness to 55.3% in group B. 38.3% of the patients in group C had expiratory muscle weakness as measured by maximum expiratory pressure (Pemax) compared with 36.7% when weakness was diagnosed by cough gastric pressure (Pgas), and 28.3% when

  10. 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

  11. 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/

  12. Slip on 'weak' faults by the rotation of regional stress in the fracture damage zone.

    PubMed

    Faulkner, D R; Mitchell, T M; Healy, D; Heap, M J

    2006-12-14

    Slip on unfavourably oriented faults with respect to a remotely applied stress is well documented and implies that faults such as the San Andreas fault and low-angle normal faults are weak when compared to laboratory-measured frictional strength. If high pore pressure within fault zones is the cause of such weakness, then stress reorientation within or close to a fault is necessary to allow sufficient fault weakening without the occurrence of hydrofracture. From field observations of a major tectonic fault, and using laboratory experiments and numerical modelling, here we show that stress rotation occurs within the fractured damage zone surrounding faults. In particular, we find that stress rotation is considerable for unfavourably oriented 'weak' faults. In the 'weak' fault case, the damage-induced change in elastic properties provides the necessary stress rotation to allow high pore pressure faulting without inducing hydrofracture. PMID:17167484

  13. 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.

  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. 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

  16. 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

  17. Shock strength versus range from underwater nuclear explosions

    SciTech Connect

    Rosenkilde, C.E.

    1987-01-27

    Annotated viewgraphs describe the variation in pulse strength and duration as strong and weak spherical shock waves propagate through uniform, homogeneous water from a nuclear explosive source. Asymptotic relationships for strong and weak shocks are re-expressed in intrinsic non-dimensional units. These relationships are combined to obtain continuous interpolation formulas, which span the entire spatial range from the near-source region out through the far field of interest in submarine damage prediction. Comparisons are made between the semi-empirical results of Snay and some more recent hydrocode calculations by Kamegai. 8 refs., 20 figs.

  18. Prepubescent Strength Training. Some Considerations.

    ERIC Educational Resources Information Center

    Priest, Joe W.; Holshouser, Richard S.

    1987-01-01

    Under the careful supervision of a trained fitness professional, the benefits of prepubescent strength training (improved strength, power, muscular endurance, bone density) outweigh the risks (acute and chronic musculoskeletal injuries). (CB)

  19. 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.

  20. 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.

  1. Intermediate Strength Gravitational Lensing

    SciTech Connect

    Irwin, John

    2005-03-17

    Weak lensing is found in the correlations of shear in {approx}10{sup 4} galaxy images, strong lensing is detected by the obvious distortion of a single galaxy image, whereas intermediate lensing requires detection of less obvious curvature in several neighboring galaxies. Small impact-parameter lensing causes a sextupole distortion whose orientation is correlated with the quadrupole distortion (shear). By looking within a field for the spatial correlation of this sextupole-quadrupole correlation, an intermediate lensing regime is observed. This technique requires correction for the sextupole as well as the quadrupole content of the PSF. We remove the HST PSF and uncover intermediate lensing in the Hubble deep fields. Correlations of the type expected are found.

  2. Strength of Rewelded Inconel 718

    NASA Technical Reports Server (NTRS)

    Bayless, E.; Lovoy, C. V.; Mcllwain, M. C.; Munafo, P.

    1982-01-01

    Inconel 718, nickel-based alloy used extensively for high-temperature structural service, welded repeatedly without detriment to its strength. According to NASA report, tests show 12 repairs on same weld joint do not adversely affect ultimate tensile strenth, yield strength, fatigue strength, metallurgical grain structures, or ability of weld joint to respond to post weld heat treatments.

  3. 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…

  4. 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…

  5. 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.

  6. Contribution of Quadriceps Weakness to Fragility Fracture: A Prospective Study.

    PubMed

    Pham, Hanh M; Nguyen, Nguyen D; Center, Jacqueline R; Eisman, John A; Nguyen, Tuan V

    2016-01-01

    The association between muscle weakness and fracture is not well understood. This study sought to examine the contribution of muscle strength at baseline and change in muscle strength to the observed risk of fragility fracture in older people. The study involved 595 men and 1066 women aged 60+ years (median 69 years) who had been followed for a median of 11 years (range, 4 to 22 years). Quadriceps isometric muscle strength (MS) measured at baseline and biennially was adjusted for height. Femoral neck bone mineral density (FNBMD) was measured by DXA. Low-trauma fracture was ascertained from X-ray reports and interview. The relationship between baseline MS and serial MS and fracture assessed by time-invariant and time-variant Cox's regression models was expressed as hazard ratio (HR) and 95% confidence interval (CI). During the follow-up period, 282 (26%) women and 89 (15%) men sustained a fragility fracture. From age 60 years, women lost 0.28 kg/m (1.6%) of MS per year, whereas men lost 0.39 kg/m (1.5%) of MS per year. In the time-variant model, using serial MS, each 1 SD (4.7 kg/m) lower MS was associated with a 27% increase in the risk of fracture in women (HR 1.27; 95% CI, 1.11 to 1.43); and 46% increase in men (HR 1.46; 95% CI, 1.22 to 1.75). After adjusting for FNBMD, age and prior fracture, history of fall and smoking, HR per SD of lower MS was 1.13 (95% CI, 0.99 to 1.28) for women and 1.35 (95% CI, 1.18 to 1.64) for men. These data indicate that muscle weakness is an independent determinant of fracture risk in men, but not in women. This sex difference suggests that apart from mechanical load effect of muscle on bone, there are other muscle-bone interactions that need to be investigated in future studies. The accuracy of fracture risk prediction for men may be improved by incorporating muscle strength. PMID:26174768

  7. Reversing entanglement change by a weak measurement

    SciTech Connect

    Sun Qingqing; Zubairy, M. Suhail; Al-Amri, M.; Davidovich, Luiz

    2010-11-15

    Entanglement of a system changes due to interactions with the environment. A typical type of interaction is amplitude damping. If we add a detector to monitor the environment and only select the no-damping outcome, this amplitude damping is modified into a weak measurement. Here we show that the entanglement change of a two-qubit state due to amplitude damping or weak measurement can be probabilistically reversed. For the amplitude-damping case, the entanglement partially recovers under most conditions. For the weak-measurement case, the recovery of the initial entangled state is exact. The reversal procedure involves another weak measurement, preceded and followed by bit flips applied to both qubits. We propose a linear optics scheme for the experimental demonstration of these procedures.

  8. Composite weld rod corrects individual filler weaknesses

    NASA Technical Reports Server (NTRS)

    Grimaldo, S.

    1967-01-01

    Composite filler wire welds together an assembly made from components of Rene 41 nickel base alloy. Using equal parts of Rene 41 and Hastelloy W weld wire in the filler reduces the cracking and weaknesses of the individual parent metals.

  9. 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.

  10. 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.

  11. Elastic scattering with weakly bound projectiles

    SciTech Connect

    Figueira, J. M.; Abriola, D.; Arazi, A.; Capurro, O. A.; Marti, G. V.; Martinez Heinmann, D.; Pacheco, A. J.; Testoni, J. E.; Barbara, E. de; Fernandez Niello, J. O.; Padron, I.; Gomes, P. R. S.; Lubian, J.

    2007-02-12

    Possible effects of the break-up channel on the elastic scattering threshold anomaly has been investigated. We used the weakly bound 6,7Li nuclei, which is known to undergo break-up, as projectiles in order to study the elastic scattering on a 27Al target. In this contribution we present preliminary results of these experiments, which were analyzed in terms of the Optical Model and compared with other elastic scattering data using weakly bound nuclei as projectile.

  12. 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

  13. 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.

  14. Delayed feedback control of synchronization in weakly coupled oscillator networks

    NASA Astrophysics Data System (ADS)

    Novičenko, Viktor

    2015-08-01

    We study control of synchronization in weakly coupled oscillator networks by using a phase-reduction approach. Starting from a general class of limit-cycle oscillators we derive a phase model, which shows that delayed feedback control changes effective coupling strengths and effective frequencies. We derive the analytical condition for critical control gain, where the phase dynamics of the oscillator becomes extremely sensitive to any perturbations. As a result the network can attain phase synchronization even if the natural interoscillatory couplings are small. In addition, we demonstrate that delayed feedback control can disrupt the coherent phase dynamic in synchronized networks. The validity of our results is illustrated on networks of diffusively coupled Stuart-Landau and FitzHugh-Nagumo models.

  15. 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

  16. 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

  17. Atypical presentation of GNE myopathy with asymmetric hand weakness

    PubMed Central

    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

    2014-01-01

    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

  18. 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

  19. 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.

  20. 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.

  1. The benefits of strength training for older adults.

    PubMed

    Seguin, Rebecca; Nelson, Miriam E

    2003-10-01

    Aging is associated with a number of physiologic and functional declines that can contribute to increased disability, frailty, and falls. Contributing factors are the loss of muscle mass and strength as age increases, a phenomenon called sarcopenia. Sarcopenia can result or be exacerbated by certain chronic conditions, and can also increase the burden of chronic disease. Current research has demonstrated that strength-training exercises have the ability to combat weakness and frailty and their debilitating consequences. Done regularly (e.g., 2 to 3 days per week), these exercises build muscle strength and muscle mass and preserve bone density, independence, and vitality with age. In addition, strength training also has the ability to reduce the risk of osteoporosis and the signs and symptoms of numerous chronic diseases such as heart disease, arthritis, and type 2 diabetes, while also improving sleep and reducing depression. This paper reviews the current research on strength training and older adults, evaluating exercise protocols in a variety of populations. It is clear that a variety of strength-training prescriptions from highly controlled laboratory-based to minimally supervised home-based programs have the ability to elicit meaningful health benefits in older adults. The key challenges as this field of exercise science moves forward are to best identify the most appropriate strength-training recommendations for older adults and to greatly increase the access to safe and effective programs in a variety of settings. PMID:14552938

  2. Production of high strength concrete

    SciTech Connect

    Peterman, M.B.; Carrasquillo, R.L.

    1986-01-01

    The criteria for selection of concrete materials and their proportions to producer uniform, economical, high strength concrete are presented in this book. The recommendations provided are based on a study of the interactions among components of plain concrete and mix proportions, and of their contribution to the compressive strength of high strength concrete. These recommendations will serve as guidelines to practicing engineers, in the selection of materials and their proportions for the production of high strength concrete. Increasing demands for improved efficiency and reduced construction costs have resulted in engineers beginning to design large structures using higher strength concrete at higher stress levels. There are definite advantages, both technical and economical, in using high strength concrete. For example, for a given cross section, prestresses concrete bridge girders can carry greater service loads across longer spans if made using high strength concrete. In addition, cost comparisons have shown that the savings obtained are significantly greater than the added cost of the higher quality concrete.

  3. Mafic granulite rheology: Implications for a weak continental lower crust

    NASA Astrophysics Data System (ADS)

    Wang, Y. F.; Zhang, J. F.; Jin, Z. M.; Green, H. W.

    2012-11-01

    The “jelly sandwich” model of continental rheology, long the consensus model, has recently been challenged. The controversy is based on the rheology of mafic granulite that is thought to make up most of the lower continental crust. However, because of technical issues in experimental rock deformation, there are very few data on this problem. Here we report the rheology and fabrics of a reconstituted, fine-grained nominally dry (i.e., no hydrous mineral) mafic granulite (57% plagioclase+24% clinopyroxene+14% orthopyroxene+5% opaque minerals, 0.16-0.28 wt% H2O) deformed at 1.1-1.2 GPa pressure in a modified Griggs-type deformation apparatus. The rheology of this mafic granulite can be described by the constitutive equation of ε˙=Aσexp(-(244±35 kJ/mol)/RT) where ε˙ is in s-1, σ in MPa, T in Kelvin and A=10-2.0±1.6 MPa-3.2 s-1. Our results provide new experimental evidence in support of the “jelly sandwich” lithosphere strength model and imply that mafic granulite with a moderate amount of water (>0.05-0.08 wt% H2O) is likely to be a weak layer in the lithosphere. Both pyroxenes and plagioclase develop pronounced fabrics in responding to axial deformation. The deformation mechanism is dislocation creep with (100)[001], and (001)[100]/(010)[100] being the dominant slip systems for pyroxenes and plagioclase, respectively. The low strength of mafic granulite is ascribed largely to the significant weakening effect of dissolved water in pyroxenes and plagioclase. A weak continental lower crust has many important implications for geodynamics of crust-mantle interactions, such as lower crust channel flow and delamination.

  4. 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.

  5. Effective Binding of Methane Using a Weak Hydrogen Bond.

    PubMed

    Henley, Alice; Bound, Michelle; Besley, Elena

    2016-05-26

    The weak hydrogen bond is an important type of noncovalent interaction, which has been shown to contribute to stability and conformation of proteins and large biochemical membranes, stereoselectivity, crystal packing, and effective gas storage in porous materials. In this work, we systematically explore the interaction of methane with a series of functionalized organic molecules specifically selected to exhibit a weak hydrogen bond with methane molecules. To enhance the strength of hydrogen bond interactions, the functional groups include electron-enriched sites to allow sufficient polarization of the C-H bond of methane. The binding between nine functionalized benzene molecules and methane has been studied using the second order Møller-Plesset perturbation theory to reveal that benzenesulfonic acid (C6H5-SO3H) and phenylphosphonic acid (C6H5-PO3H2) have the greatest potential for efficient methane capture through hydrogen bonding interactions. Both acids exhibit efficient binding potential with up to three methane molecules. For additional insight, the atomic charge distribution associated with each binding site is presented. PMID:27148999

  6. Efficiency of weak brain connections support general cognitive functioning.

    PubMed

    Santarnecchi, Emiliano; Galli, Giulia; Polizzotto, Nicola Riccardo; Rossi, Alessandro; Rossi, Simone

    2014-09-01

    Brain network topology provides valuable information on healthy and pathological brain functioning. Novel approaches for brain network analysis have shown an association between topological properties and cognitive functioning. Under the assumption that "stronger is better", the exploration of brain properties has generally focused on the connectivity patterns of the most strongly correlated regions, whereas the role of weaker brain connections has remained obscure for years. Here, we assessed whether the different strength of connections between brain regions may explain individual differences in intelligence. We analyzed-functional connectivity at rest in ninety-eight healthy individuals of different age, and correlated several connectivity measures with full scale, verbal, and performance Intelligent Quotients (IQs). Our results showed that the variance in IQ levels was mostly explained by the distributed communication efficiency of brain networks built using moderately weak, long-distance connections, with only a smaller contribution of stronger connections. The variability in individual IQs was associated with the global efficiency of a pool of regions in the prefrontal lobes, hippocampus, temporal pole, and postcentral gyrus. These findings challenge the traditional view of a prominent role of strong functional brain connections in brain topology, and highlight the importance of both strong and weak connections in determining the functional architecture responsible for human intelligence variability. PMID:24585433

  7. Systematics of strength function sum rules

    DOE PAGESBeta

    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

  8. 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).

  9. Systematics of strength function sum rules

    NASA Astrophysics Data System (ADS)

    Johnson, Calvin W.

    2015-11-01

    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 expects sum rules to evolve with excitation energy. Furthermore, to lowest order the slope of the secular evolution can be traced to a component of the Hamiltonian being positive (repulsive) or negative (attractive).

  10. 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.

  11. Collective transport of weakly interacting molecular motors with Langmuir kinetics

    NASA Astrophysics Data System (ADS)

    Chandel, Sameep; Chaudhuri, Abhishek; Muhuri, Sudipto

    2015-04-01

    Filament-based intracellular transport involves the collective action of molecular motor proteins. Experimental evidences suggest that microtubule (MT) filament bound motor proteins such as kinesins weakly interact among themselves during transport and with the surrounding cellular environment. Motivated by these observations we study a driven lattice gas model for collective unidirectional transport of molecular motors on open filament. This model incorporates short-range next-nearest-neighbour (NNN) interactions between the motors and couples the transport process on filament with surrounding cellular environment through adsorption-desorption Langmuir kinetics (LK) of the motors. We analyse this model within the framework of a mean-field (MF) theory in the limit of weak interactions between the motors. We point to the mapping of this model with the non-conserved version of the Katz-Lebowitz-Spohn (KLS) model. The system exhibits rich phase behavior with a variety of inhomogeneous phases including localized shocks in the bulk of the filament. We obtain the steady-state density and current profiles, analyse their variation as a function of the strength of interaction and construct the non-equilibrium MF phase diagram. We compare these MF results with Monte Carlo simulations and find that the MF analysis shows reasonably good agreement with simulation results as long as the motors are weakly interacting. For sufficently strong NNN interaction between the motors, the mean-field results deviate significantly, and for very strong NNN interaction in the absence of LK, the current in the lattice is determined solely by the NNN interaction parameter and it becomes independent of entry and exit rates of motors at the filament boundaries.

  12. Fault Roughness Records Strength

    NASA Astrophysics Data System (ADS)

    Brodsky, E. E.; Candela, T.; Kirkpatrick, J. D.

    2014-12-01

    Fault roughness is commonly ~0.1-1% at the outcrop exposure scale. More mature faults are smoother than less mature ones, but the overall range of roughness is surprisingly limited which suggests dynamic control. In addition, the power spectra of many exposed fault surfaces follow a single power law over scales from millimeters to 10's of meters. This is another surprising observation as distinct structures such as slickenlines and mullions are clearly visible on the same surfaces at well-defined scales. We can reconcile both observations by suggesting that the roughness of fault surfaces is controlled by the maximum strain that can be supported elastically in the wallrock. If the fault surface topography requires more than 0.1-1% strain, it fails. Invoking wallrock strength explains two additional observations on the Corona Heights fault for which we have extensive roughness data. Firstly, the surface is isotropic below a scale of 30 microns and has grooves at larger scales. Samples from at least three other faults (Dixie Valley, Mount St. Helens and San Andreas) also are isotropic at scales below 10's of microns. If grooves can only persist when the walls of the grooves have a sufficiently low slope to maintain the shape, this scale of isotropy can be predicted based on the measured slip perpendicular roughness data. The observed 30 micron scale at Corona Heights is consistent with an elastic strain of 0.01 estimated from the observed slip perpendicular roughness with a Hurst exponent of 0.8. The second observation at Corona Heights is that slickenlines are not deflected around meter-scale mullions. Yielding of these mullions at centimeter to meter scale is predicted from the slip parallel roughness as measured here. The success of the strain criterion for Corona Heights supports it as the appropriate control on fault roughness. Micromechanically, the criterion implies that failure of the fault surface is a continual process during slip. Macroscopically, the

  13. 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

  14. 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

  15. 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.

  16. Weak crystallization theory of metallic alloys

    NASA Astrophysics Data System (ADS)

    Martin, Ivar; Gopalakrishnan, Sarang; Demler, Eugene A.

    2016-06-01

    Crystallization is one of the most familiar, but hardest to analyze, phase transitions. The principal reason is that crystallization typically occurs via a strongly first-order phase transition, and thus rigorous treatment would require comparing energies of an infinite number of possible crystalline states with the energy of liquid. A great simplification occurs when crystallization transition happens to be weakly first order. In this case, weak crystallization theory, based on unbiased Ginzburg-Landau expansion, can be applied. Even beyond its strict range of validity, it has been a useful qualitative tool for understanding crystallization. In its standard form, however, weak crystallization theory cannot explain the existence of a majority of observed crystalline and quasicrystalline states. Here we extend the weak crystallization theory to the case of metallic alloys. We identify a singular effect of itinerant electrons on the form of weak crystallization free energy. It is geometric in nature, generating strong dependence of free energy on the angles between ordering wave vectors of ionic density. That leads to stabilization of fcc, rhombohedral, and icosahedral quasicrystalline (iQC) phases, which are absent in the generic theory with only local interactions. As an application, we find the condition for stability of iQC that is consistent with the Hume-Rothery rules known empirically for the majority of stable iQC; namely, the length of the primary Bragg-peak wave vector is approximately equal to the diameter of the Fermi sphere.

  17. 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

  18. 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

  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. Persisting weakness after withdrawal of a statin

    PubMed Central

    Mygland, Åse; Ljøstad, Unn; Krossnes, Bård Kronen

    2014-01-01

    An 81-year-old woman treated with simvastatin for several years followed by atorvastatin for about 1 year presented with fatigue, weakness and unsteady gait. The finding of elevated creatine kinase (CK) and symmetric muscle weakness around shoulders and hips led to suspicion of a toxic statin-associated myopathy. Atorvastatin was withdrawn, but her weakness persisted. Owing to persisting weakness, an autoimmune myopathy (myositis) was suspected, but initially disregarded since a muscle biopsy showed necrotic muscle fibres without inflammatory cell infiltrates and myositis-specific autoantibodies were absent. After 18 months with slowly progressive weakness and increasing CK values, awareness of new knowledge about autoimmunity as a cause of necrotic myopathy, led to a successful treatment trial with intravenous immunoglobulines, followed by steroids and metothrexate. Antibodies to the target enzyme of statins (HMGCR (3-hydroksy-3-methylglutaryl-coenzyme A reductase)) were detected in her serum, and she was diagnosed with autoimmune necrotic myositis probably triggered by atorvastatin. PMID:24713712

  1. Airborne field strength monitoring

    NASA Astrophysics Data System (ADS)

    Bredemeyer, J.; Kleine-Ostmann, T.; Schrader, T.; Münter, K.; Ritter, J.

    2007-06-01

    In civil and military aviation, ground based navigation aids (NAVAIDS) are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS) increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR) is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000) by the International Civil Aviation Organization (ICAO). One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz), the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA) accelerated method of moments (MoM) using a complex geometric model of the aircraft. First results will be presented in this paper.

  2. 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.

  3. Disturbance in weak measurements and the difference between quantum and classical weak values

    NASA Astrophysics Data System (ADS)

    Ipsen, Asger C.

    2015-06-01

    The role of measurement-induced disturbance in weak measurements is of central importance for the interpretation of the weak value. Uncontrolled disturbance can interfere with the postselection process and make the weak value dependent on the details of the measurement process. Here we develop the concept of a generalized weak measurement for classical and quantum mechanics. The two cases appear remarkably similar, but we point out some important differences. A priori it is not clear what the correct notion of disturbance should be in the context of weak measurements. We consider three different notions and get three different results: (1) For a "strong" definition of disturbance, we find that weak measurements are disturbing. (2) For a weaker definition we find that a general class of weak measurements is nondisturbing, but that one gets weak values which depend on the measurement process. (3) Finally, with respect to an operational definition of the "degree of disturbance," we find that the AAV weak measurements are the least disturbing, but that the disturbance is always nonzero.

  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. Inspecting the Higgs for new weakly interacting particles

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; McDermott, Samuel D.; Zurek, Kathryn M.

    2013-04-01

    We explore new physics scenarios which are optimally probed through precision Higgs measurements rather than direct collider searches. Such theories consist of additional electroweak charged or singlet states which couple directly to or mix with the Higgs boson; particles of this kind may be weakly constrained by direct limits due to their meager production rates and soft decay products. We present a simplified framework which characterizes the effects of these states on Higgs physics by way of tree level mixing (with neutral scalars) and loop level modifications (from electrically charged states), all expressed in terms of three mixing angles and three loop parameters, respectively. The theory parameters are constrained and in some cases even fixed by ratios of Higgs production and decay rates. Our setup is simpler than a general effective operator analysis, in that we discard parameters irrelevant to Higgs observables while retaining complex correlations among measurements that arise due to the underlying mixing and radiative effects. We show that certain correlated observations are forbidden, e.g. a depleted ratio of Higgs production from gluon fusion versus vector boson fusion together with a depleted ratio of Higgs decays to boverline{b} versus WW. Moreover, we study the strong correlation between the Higgs decay rate to γγ and WW and how it can be violated in the presence of additional electrically charged particles. Our formalism maps straightforwardly onto a variety of new physics models, such as the NMSSM. We show, for example, that with a Higgsino of mass {m_{{χ_1^{± }}}}gtrsim 100 GeV and a singlet-Higgs coupling of λ = 0.7, the photon signal strength can deviate from the vector signal strength by up to ˜ 40 - 60% while depleting the vector signal strength by only 5 - 15% relative to the Standard Model.

  6. 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…

  7. Weak localization effect in superconducting thin films

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Jihn; Chang, K. J.

    1997-03-01

    It was claimed(1. R. C. Dynes et al., Phys. Rev. Lett. 57), 2195 (1986). that the Eliashberg theory breaks down for two-dimensional superconductivity in weakly disordered systems. From tunneling measurements on Pb films, both the electron-phonon interaction λ and the Coulomb pseudopotential μ^* were suggested to decrease by disordering. In this problem, it was previously noted that the Dyson expansion of Green's function in the presence of impurities is inappropriate.(2. Y.-J. Kim and A. W. Overhauser, Phys. Rev. B47), 8025 (1993). Alternatively, employing time-reversed scattered-state pairs, we note that the phonon-mediated coupling parameter λ is decreased by weak localization. With solving both the BCS and Eliashberg gap equations, we find good agreements between our calculations and existing experimental data. We also discuss the weak localization effect on superconductivity in one- and three-dimensional systems.

  8. 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.

  9. Dispersion relations in weakly degenerate plasmas

    NASA Astrophysics Data System (ADS)

    Rocchi, F.; Molinari, V. G.; Mostacci, D.; Sumini, M.

    2001-06-01

    From a quantum mechanical point of view, electrons in laser produced plasmas can be regarded as weakly degenerate. For instance, for a plasma with electron density of 10 22 cm -3 and electron temperature of 1 eV, Sommerfeld's parameter is between 1 and 2. Under these conditions the usual dispersion relations for waves in plasmas need be corrected to account for degeneracy. In the present work, starting from the transport equation with a simplified version of the Boltzmann-Uehling-Uhlenbeck collision kernel the propagation of waves impinging on a plasma with weakly degenerate electrons is investigated and dispersion relations accounting for degeneracy are derived. These dispersion relations give the classical ones in the limit for Sommerfeld's parameter approaching zero. A shift of the wavenumber value and a non-collisional damping due to degeneracy effects are predicted which render a weakly degenerate plasma more opaque to radiation than a non-degenerate one.

  10. 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.

  11. On configurational weak phase transitions in graphene

    NASA Astrophysics Data System (ADS)

    Sfyris, Dimitris

    2016-07-01

    We report a study on configurational weak phase transitions for a freestanding monolayer graphene. Firstly, we characterize weak transformation neighborhoods by suitably bounding the metric components. Then, we distinguish between structural and configurational phase changes and elaborate on the second class of them. We evaluate the irreducible invariant subspaces corresponding to these phase changes and lay down symmetry-breaking as well as symmetry-preserving stretches. In the reduced bifurcation diagram, symmetry-preserving stretches are related to a turning point with a change of stability but not of symmetry. Symmetry-breaking stretches are related to a first-order weak phase transition. We evaluate symmetry-breaking stretches as well as their generating cosets. The reduced bifurcation diagram consists of three transcritical bifurcating curves which are all unstable but can be stabilized producing a subcritical bifurcation. We, also, shortly comment on the hysteretical behavior that might appear in this case.

  12. Changing smoking attitudes by strengthening weak antismoking beliefs - Taiwan as an example.

    PubMed

    Chang, Chingching

    2006-12-01

    I first explored the strength of Taiwanese high school students' beliefs regarding five antismoking messages. Findings of a nationwide survey showed that the students held these beliefs in the following order of decreasing strength: second-hand smoke damages health, smoking has long-term health consequences, smoking has short-term health consequences, cigarette marketers are manipulative, and smokers are perceived negatively. Experiment one further showed that antismoking ads featuring weakly held beliefs are more effective than those featuring strongly held beliefs. Experiment two demonstrated that antismoking campaigns need to be framed carefully; in general, it is more effective to positively frame messages about strongly held antismoking beliefs but negatively frame messages about weakly held antismoking beliefs. PMID:17190782

  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. Search for M1 strength

    SciTech Connect

    Hicks, R.S.; Peterson, G.A.

    1982-01-01

    Current knowledge of M1 transition strength in nuclei is reviewed by studying selected examples. Attention is focussed primarily on inelastic electron scattering, but information obtained using other techniques is also discussed. It appears that the utility of (e,e') as a spectroscopic tool for determining M1 strength is mainly restricted to nuclei with A < 100. For nuclei below A approx. = 40, the total measured M1 strength is in good accord with detailed shell model estimates, however heavier nuclei show a strength deficit in comparison with model predictions.

  15. 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

  16. Baryogenesis for weakly interacting massive particles

    NASA Astrophysics Data System (ADS)

    Cui, Yanou; Sundrum, Raman

    2013-06-01

    We propose a robust, unified framework, in which the similar baryon and dark matter cosmic abundances both arise from the physics of weakly interacting massive particles (WIMPs), with the rough quantitative success of the so-called “WIMP miracle.” In particular the baryon asymmetry arises from the decay of a metastable WIMP after its thermal freeze-out at or below the weak scale. A minimal model and its embedding in R-parity violating supersymmetry are studied as examples. The new mechanism saves R-parity violating supersymmetry from the potential crisis of washing out primordial baryon asymmetry. Phenomenological implications for the LHC and precision tests are discussed.

  17. 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).

  18. Weak values and the quantum phase space

    SciTech Connect

    Lobo, A. C.; Ribeiro, C. A.

    2009-07-15

    We address the issue of how to properly treat, and in a more general setting, the concept of a weak value of a weak measurement in quantum mechanics. We show that for this purpose, one must take in account the effects of the measuring process on the entire phase space of the measuring system. By using coherent states, we go a step further than Jozsa in a recent paper and we present an example where the result of the measurement is symmetrical in the position and momentum observables and seems to be much better suited for quantum optical implementation.

  19. 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.

  20. 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…

  1. Flexural strength distribution of a PMMA-based bone cement.

    PubMed

    Vallo, Claudia I

    2002-01-01

    Polymethylmethacrylate bone cement containing either no added antibiotic or 0.5 g of Gentamicin was prepared and stored either in air at room temperature or in a 37 degree C water bath for 48 h. An additive-free cement stored in air at room temperature was also tested for purposes of comparison. Following storage the specimens were tested in flexure. Weibull statistics demonstrated to fit the flexural strength distribution of all the materials tested with regression coefficients of at least 0.98. The presence of a BaSO(4) radiopacifier markedly reduced the mean flexural strength and increased the data scatter in the air-stored specimens. On the other hand, the flexural strength of both impregnated and nonimpregnated antibiotic increased when those materials were stored in water at 37 degree C, compared with the same material stored in air, as a consequence of the water ingress. The water-stored antibiotic-impregnated cement displayed lower flexural strength, increased data scatter, and a remarkably higher number of weak specimens compared with the antibiotic-free cement. The influence of the load type on the flexural behavior was studied by testing the air-stored specimens in three-point bending and four-point bending. Cements tested in four-point bending resulted in lower flexural strength than that tested in three-point bending. The ratio of mean strength measured in the different load arrangements was satisfactory, as predicted by the Weibull model. PMID:11870658

  2. The role of strength training in speech sound disorders.

    PubMed

    Clark, Heather M

    2008-11-01

    Strengthening of the articulators is commonly used to help children improve sound production accuracy, even though the relationship between weakness and speech function remains unclear. Clinicians considering the use of strength training must weigh both the theoretical foundations and the evidence supporting this practice. Widely accepted principles of strength training are available to guide the evaluation of strength training programs. Training specificity requires that exercises closely match the targeted functional outcome. The exercises must overload the muscles beyond their typical use, and this overload must be systematically progressed over time. Finally, the strength training program must incorporate adequate time between exercise sessions to allow for recovery. The available research does not support the position that nonspeech oral motor exercises (NSOMEs) targeting increased strength is beneficial for improving speech accuracy. An example of a speech-based strengthening program is provided to illustrate how appropriate training principles could lead to more positive outcomes. A much larger body of research is needed to determine the conditions under which strength training is most appropriately applied in the treatment of childhood speech disorders. PMID:19058114

  3. Zoster paresis: asymptomatic MRI lesions far beyond the site of rash and focal weakness.

    PubMed

    Tsai, Jean; Bert, Robert J; Gilden, Don

    2013-07-15

    We describe a patient with zoster paresis and an MRI that revealed extensive spinal cord lesions from the upper cervical to the lower thoracic spinal cord. Importantly, the patient reported considerable spontaneous improvement in strength 2-3 weeks after zoster. This report reveals a previously undescribed remarkable preponderance of MRI lesions far beyond the site of zoster rash and focal lower motor neuron weakness. PMID:23628467

  4. 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

  5. Anomalous skin effects in relativistic parallel propagating weakly magnetized electron plasma waves

    SciTech Connect

    Abbas, Gohar; Bashir, M. F.; Murtaza, G.

    2011-10-15

    Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized electron plasma is presented and general expressions for longitudinal and transverse permittivites are derived. It is found that the penetration depth for R- and L-waves increases as we move from non-relativistic to highly relativistic regime. The ambient magnetic field reduces/enhances the skin effects for R-wave/L-wave as the strength of the field is increased. In general, the weak magnetic field effects are pronounced for the weakly relativistic regime as compared with other relativistic cases. The results are also graphically illustrated. On switching off the magnetic field, previous results for field free case are retrieved [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Priniples of Plasma Electrodynamics (Springer-Verlag, Berlin, Heidelberg, 1984), Vol. 9, p. 106].

  6. Transition of weak wave turbulence to wave turbulence with intermittent collapses.

    PubMed

    Rumpf, Benno; Sheffield, Thomas Y

    2015-08-01

    We study the dynamics of one-dimensional nonlinear waves with a square-root dispersion. This dispersion allows strong interactions of distant modes in wave-number space, and it leads to a modulational instability of a carrier wave interacting with distant sidebands. Weak wave turbulence is found when the system is damped and weakly driven. A driving force that exceeds a critical strength leads to wave collapses coexisting with weak wave turbulence. We explain this transition behavior with the modulational instability of waves with the highest power: Below the threshold the instability is suppressed by the external long-wave damping force. Above the threshold the instability initiates wave collapses. PMID:26382495

  7. 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.

  8. Role of Weak Measurements on States Ordering and Monogamy of Quantum Correlation

    NASA Astrophysics Data System (ADS)

    Hu, Ming-Liang; Fan, Heng; Tian, Dong-Ping

    2015-01-01

    The information-theoretic definition of quantum correlation, e.g., quantum discord, is measurement dependent. By considering the more general quantum measurements, weak measurements, which include the projective measurement as a limiting case, we show that while weak measurements can enable one to capture more quantumness of correlation in a state, it can also induce other counterintuitive quantum effects. Specifically, we show that the general measurements with different strengths can impose different orderings for quantum correlations of some states. It can also modify the monogamous character for certain classes of states as well which may diminish the usefulness of quantum correlation as a resource in some protocols. In this sense, we say that the weak measurements play a dual role in defining quantum correlation.

  9. 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.

  10. 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

  11. Structure Process, Weak Values and Local Momentum

    NASA Astrophysics Data System (ADS)

    Hiley, B. J.

    2016-03-01

    We explain how weak values and the local momentum can be better understood in terms of Bohm's notion of structure process. The basic ideas of this approach can be expressed in a fully algebraic way, generalising Heisenberg's original matrix mechanics. This approach leads to questions that are now being experimentally investigated by our group at University College London.

  12. 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.

  13. 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)

  14. 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…

  15. [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

  16. 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.

  17. 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.

  18. Axion monodromy and the weak gravity conjecture

    NASA Astrophysics Data System (ADS)

    Hebecker, Arthur; Rompineve, Fabrizio; Westphal, Alexander

    2016-04-01

    Axions with broken discrete shift symmetry (axion monodromy) have recently played a central role both in the discussion of inflation and the `relaxion' approach to the hierarchy problem. We suggest a very minimalist way to constrain such models by the weak gravity conjecture for domain walls: while the electric side of the conjecture is always satisfied if the cosine-oscillations of the axion potential are sufficiently small, the magnetic side imposes a cutoff, Λ3 ˜ mf M pl, independent of the height of these `wiggles'. We compare our approach with the recent related proposal by Ibanez, Montero, Uranga and Valenzuela. We also discuss the non-trivial question which version, if any, of the weak gravity conjecture for domain walls should hold. In particular, we show that string compactifications with branes of different dimensions wrapped on different cycles lead to a `geometric weak gravity conjecture' relating volumes of cycles, norms of corresponding forms and the volume of the compact space. Imposing this `geometric conjecture', e.g. on the basis of the more widely accepted weak gravity conjecture for particles, provides at least some support for the (electric and magnetic) conjecture for domain walls.

  19. 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.

  20. 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…

  1. Strength and conditioning for triathletes.

    PubMed

    Day, Bruce; Johnson, Don

    2012-12-01

    Strength exercises for the knee, shoulder, and the core are essential to help prevent injuries to triathletes. This article will outline the most common exercises to strength the major joints and flexibility exercises to maintain range of motion of the joints. PMID:23147095

  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. 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

  4. 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.

  5. New weak keys in simplified IDEA

    NASA Astrophysics Data System (ADS)

    Hafman, Sari Agustini; Muhafidzah, Arini

    2016-02-01

    Simplified IDEA (S-IDEA) is simplified version of International Data Encryption Algorithm (IDEA) and useful teaching tool to help students to understand IDEA. In 2012, Muryanto and Hafman have found a weak key class in the S-IDEA by used differential characteristics in one-round (0, ν, 0, ν) → (0,0, ν, ν) on the first round to produce input difference (0,0, ν, ν) on the fifth round. Because Muryanto and Hafman only use three differential characteristics in one-round, we conducted a research to find new differential characteristics in one-round and used it to produce new weak key classes of S-IDEA. To find new differential characteristics in one-round of S-IDEA, we applied a multiplication mod 216+1 on input difference and combination of active sub key Z1, Z4, Z5, Z6. New classes of weak keys are obtained by combining all of these characteristics and use them to construct two new differential characteristics in full-round of S-IDEA with or without the 4th round sub key. In this research, we found six new differential characteristics in one round and combined them to construct two new differential characteristics in full-round of S-IDEA. When two new differential characteristics in full-round of S-IDEA are used and the 4th round sub key required, we obtain 2 new classes of weak keys, 213 and 28. When two new differential characteristics in full-round of S-IDEA are used, yet the 4th round sub key is not required, the weak key class of 213 will be 221 and 28 will be 210. Membership test can not be applied to recover the key bits in those weak key classes. The recovery of those unknown key bits can only be done by using brute force attack. The simulation result indicates that the bit of the key can be recovered by the longest computation time of 0,031 ms.

  6. 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 εhalo ≠ f × εlight, 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

  7. 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%.

  8. KNEE EXTENSOR STRENGTH EXHIBITS POTENTIAL TO PREDICT FUNCTION IN SPORADIC INCLUSION-BODY MYOSITIS

    PubMed Central

    LOWES, LINDA PAX; ALFANO, LINDSAY; VIOLLET, LAURENCE; ROSALES, XIOMARA QUINTERO; SAHENK, ZARIFE; KASPAR, BRIAN K.; CLARK, K. REED; FLANIGAN, KEVIN M.; MENDELL, JERRY R.

    2013-01-01

    Introduction In this study we address the challenging issue of potential use of muscle strength to predict function in clinical trials. This has immediate relevance to translational studies that attempt to improve quadriceps strength in sporadic inclusion-body myositis (sIBM). Methods Maximum voluntary isometric contraction testing as a measure of muscle strength and a battery of functional outcomes were tested in 85 ambulatory subjects with sIBM. Results Marked quadriceps weakness was noted in all patients. Strength was correlated with distance walked at 2 and 6 minutes. Additional correlations were found with time to get up from a chair, climb stairs, and step up on curbs. Conclusions Quadriceps (knee extensor) strength correlated with performance in this large cohort of sIBM subjects, which demonstrated its potential to predict function in this disease. These data provide initial support for use of muscle strength as a surrogate for function, although validation in a clinical trial is required. PMID:22246869

  9. Model reduction of strong-weak neurons.

    PubMed

    Du, Bosen; Sorensen, Danny; Cox, Steven J

    2014-01-01

    We consider neurons with large dendritic trees that are weakly excitable in the sense that back propagating action potentials are severly attenuated as they travel from the small, strongly excitable, spike initiation zone. In previous work we have shown that the computational size of weakly excitable cell models may be reduced by two or more orders of magnitude, and that the size of strongly excitable models may be reduced by at least one order of magnitude, without sacrificing the spatio-temporal nature of its inputs (in the sense we reproduce the cell's precise mapping of inputs to outputs). We combine the best of these two strategies via a predictor-corrector decomposition scheme and achieve a drastically reduced highly accurate model of a caricature of the neuron responsible for collision detection in the locust. PMID:25566048

  10. 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.

  11. 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.

  12. 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}.

  13. Model reduction of strong-weak neurons

    PubMed Central

    Du, Bosen; Sorensen, Danny; Cox, Steven J.

    2014-01-01

    We consider neurons with large dendritic trees that are weakly excitable in the sense that back propagating action potentials are severly attenuated as they travel from the small, strongly excitable, spike initiation zone. In previous work we have shown that the computational size of weakly excitable cell models may be reduced by two or more orders of magnitude, and that the size of strongly excitable models may be reduced by at least one order of magnitude, without sacrificing the spatio–temporal nature of its inputs (in the sense we reproduce the cell's precise mapping of inputs to outputs). We combine the best of these two strategies via a predictor-corrector decomposition scheme and achieve a drastically reduced highly accurate model of a caricature of the neuron responsible for collision detection in the locust. PMID:25566048

  14. 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.

  15. Experimental observation of weak non-Markovianity

    PubMed Central

    Bernardes, Nadja K.; Cuevas, Alvaro; Orieux, Adeline; Monken, C. H.; Mataloni, Paolo; Sciarrino, Fabio; Santos, Marcelo F.

    2015-01-01

    Non-Markovianity has recently attracted large interest due to significant advances in its characterization and its exploitation for quantum information processing. However, up to now, only non-Markovian regimes featuring environment to system backflow of information (strong non-Markovianity) have been experimentally simulated. In this work, using an all-optical setup we simulate and observe the so-called weak non-Markovian dynamics. Through full process tomography, we experimentally demonstrate that the dynamics of a qubit can be non-Markovian despite an always increasing correlation between the system and its environment which, in our case, denotes no information backflow. We also show the transition from the weak to the strong regime by changing a single parameter in the environmental state, leading us to a better understanding of the fundamental features of non-Markovianity. PMID:26627910

  16. Experimental observation of weak non-Markovianity.

    PubMed

    Bernardes, Nadja K; Cuevas, Alvaro; Orieux, Adeline; Monken, C H; Mataloni, Paolo; Sciarrino, Fabio; Santos, Marcelo F

    2015-01-01

    Non-Markovianity has recently attracted large interest due to significant advances in its characterization and its exploitation for quantum information processing. However, up to now, only non-Markovian regimes featuring environment to system backflow of information (strong non-Markovianity) have been experimentally simulated. In this work, using an all-optical setup we simulate and observe the so-called weak non-Markovian dynamics. Through full process tomography, we experimentally demonstrate that the dynamics of a qubit can be non-Markovian despite an always increasing correlation between the system and its environment which, in our case, denotes no information backflow. We also show the transition from the weak to the strong regime by changing a single parameter in the environmental state, leading us to a better understanding of the fundamental features of non-Markovianity. PMID:26627910

  17. Weak Decays of Excited B Mesons

    NASA Astrophysics Data System (ADS)

    Grinstein, B.; Martin Camalich, J.

    2016-04-01

    We investigate the decays of the excited (b q ¯) mesons as probes of the short-distance structure of the weak Δ B =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 Bs*→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 Bs* width. We discuss the prospects for producing this decay mode at the LHC and explore the possibility of measuring the Bs*→ℓℓ amplitude, instead, through scattering experiments at the Bs* resonance peak.

  18. 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.

  19. Thermoelectric performance of weakly coupled granular materials.

    SciTech Connect

    Glatz, A.; Beloborodov, I. S.; Materials Science Division; California State Univ. at Northridge

    2009-01-01

    We study thermoelectric properties of inhomogeneous nanogranular materials for weak tunneling conductance between the grains, g{sub t} < 1. We calculate the thermopower and figure of merit taking into account the shift of the chemical potential and the asymmetry of the density of states in the vicinity of the Fermi surface. We show that the weak coupling between the grains leads to a high thermopower and low thermal conductivity resulting in relatively high values of the figure of merit on the order of one. We estimate the temperature at which the figure of merit has its maximum value for two- and three-dimensional samples. Our results are applicable for many emerging materials, including artificially self-assembled nanoparticle arrays.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Anisotropy of weakly vibrated granular flows

    NASA Astrophysics Data System (ADS)

    Wortel, Geert H.; van Hecke, Martin

    2015-10-01

    We experimentally probe the anisotropy of weakly vibrated flowing granular media. Depending on the driving parameters—flow rate and vibration strength—this anisotropy varies significantly. We show how the anisotropy collapses when plotted as a function of the driving stresses, uncovering a direct link between stresses and anisotropy. Moreover, our data suggest that for small anisotropies, the shear stresses vanish. Anisotropy of the fabric of granular media thus plays a crucial role in determining the rheology of granular flows.

  6. 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.

  7. Weak coupling tests of lattice QCD

    SciTech Connect

    Kovacs, E.

    1984-01-01

    For many arbitrary lattices with arbitrary SU(N) actions, the perturbative value of ..lambda../sub latt//..lambda../sub MOM/ can be estimated from the Monte Carlo data at weak coupling by analyzing the perturbative expansions for various Wilson loop ratios. Here, general loop ratios including those of polygons and parallelograms are considered. The lowest order perturbative expansions are calculated and some applications to the Monte Carlo data are presented.

  8. Chaotic dynamics of weakly nonlinear systems

    SciTech Connect

    Vavriv, D.M.

    1996-06-01

    A review is given on the recent results in studying chaotic phenomena in weakly nonlinear systems. We are concerned with the class of chaotic states that can arise in physical systems with any degree of nonlinearity however small. The conditions for, and the mechanisms of, the transitions to chaos are discussed. These findings are illustrated by the results of the stability analysis of practical microwave and optical devices. {copyright} {ital 1996 American Institute of Physics.}

  9. Fusion and Breakup of Weakly Bound Nuclei

    SciTech Connect

    Gomes, P. R. S.; Lubian, J.; Padron, I.; Crema, E.; Chamon, L. C.; Hussein, M. S.; Canto, L. F.

    2006-08-14

    We discuss the influence of the breakup process of weakly bound nuclei on the fusion cross section. The complete fusion for heavy targets is found to be suppressed due to the incomplete fusion following the breakup, whereas this effect is negligible for light targets. The total fusion cross sections for stable projectiles are not affected by the breakup process, whereas it is suppressed for halo projectiles. The non capture breakup is the dominant process at sub-barrier energies.

  10. 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. PMID:27170527

  11. Co-activation: its association with weakness and specific neurological pathology

    PubMed Central

    Busse, Monica E; Wiles, Charles M; van Deursen, Robert WM

    2006-01-01

    Background Net agonist muscle strength is in part determined by the degree of antagonist co-activation. The level of co-activation might vary in different neurological disorders causing weakness or might vary with agonist strength. Aim This study investigated whether antagonist co-activation changed a) with the degree of muscle weakness and b) with the nature of the neurological lesion causing weakness. Methods Measures of isometric quadriceps and hamstrings strength were obtained. Antagonist (hamstring) co-activation during knee extension was calculated as a ratio of hamstrings over quadriceps activity both during an isometric and during a functional sit to stand (STS) task (using kinematics) in groups of patients with extrapyramidal (n = 15), upper motor neuron (UMN) (n = 12), lower motor neuron (LMN) with (n = 18) or without (n = 12) sensory loss, primary muscle or neuromuscular junction disorder (n = 17) and in healthy matched controls (n = 32). Independent t-tests or Mann Witney U tests were used to compare between the groups. Correlations between variables were also investigated. Results In healthy subjects mean (SD) co-activation of hamstrings during isometric knee extension was 11.8 (6.2)% and during STS was 20.5 (12.9)%. In patients, co-activation ranged from 7 to 17% during isometric knee extension and 15 to 25% during STS. Only the extrapyramidal group had lower co-activation levels than healthy matched controls (p < 0.05). Agonist isometric muscle strength and co-activation correlated only in muscle disease (r = -0.6, p < 0.05) and during STS in UMN disorders (r = -0.7, p < 0.5). Conclusion It is concluded that antagonist co-activation does not systematically vary with the site of neurological pathology when compared to healthy matched controls or, in most patient groups, with strength. The lower co-activation levels found in the extrapyramidal group require confirmation and further investigation. Co-activation may be relevant to individuals with muscle

  12. Age-Related Weakness of Proximal Muscle Studied with Motor Cortical Mapping: A TMS Study

    PubMed Central

    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

  13. 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.

  14. Weak lensing of the primary CMB bispectrum

    SciTech Connect

    Cooray, Asantha; Sarkar, Devdeep; Serra, Paolo

    2008-06-15

    The bispectrum of cosmic microwave background (CMB) anisotropies is a well-known probe of the non-Gaussianity of primordial perturbations. Just as the intervening large-scale structure modifies the CMB angular power spectrum through weak gravitational lensing, the CMB primary bispectrum generated at the last scattering surface is also modified by lensing. We discuss the lensing modification to the CMB bispectrum and show that lensing leads to an overall decrease in the amplitude of the primary bispectrum at multipoles of interest between 100 and 2000 through additional smoothing introduced by lensing. Since weak lensing is not accounted for in current estimators of the primordial non-Gaussianity parameter, the existing measurements of f{sub NL} of the local model with WMAP out to l{sub max}{approx}750 is biased low by about 6%. For a high resolution experiment such as Planck, the lensing modification to the bispectrum must be properly included when attempting to estimate the primordial non-Gaussianity or the bias will be at the level of 30%. For Planck, weak lensing increases the minimum detectable value for the non-Gaussianity parameter of the local type f{sub NL} to 7 from the previous estimate of about 5 without lensing. The minimum detectable value of f{sub NL} for a cosmic variance limited experiment is also increased from less than 3 to {approx}5.

  15. Weak double layers in the auroral ionosphere

    NASA Technical Reports Server (NTRS)

    Hudson, M. K.; Crystal, T. L.; Lotko, W.; Barnes, C.

    1987-01-01

    Previous work on the evolution of weak double layers in a hydrogen plasma was extended to include H(+) and O(+) with relative drift. The relative drift between hydrogen and oxygen ions due to a quasi-static parallel electric field gives rise to a strong linear fluid instability which dominates the ion-acoustic mode at the bottom of the auroral acceleration region. This ion-ion instability can modify ion distributions at lower altitudes and the subsequent nonlinear evolution of weak double layers at higher altitudes in the ion-acoustic regime. Ion hole formation can occur for smaller relative electron-ion drifts than seen in previous simulations, due to the hydrogen-oxygen two-stream instability. This results in local modification of the ion distributions in phase space, and a partial filling of the valley between the hydrogen and oxygen peaks, which would be expected at higher altitudes on auroral field lines. The observed velocity diffusion does not necessarily preclude ion hole and double layer formation in hydrogen in the ion-acoustic regime. These simulation results are consistent with the experimentally measured persistence of separate hydrogen and oxygen peaks, and the observation of weak double layers above an altitude of 3000 km on auroral field lines.

  16. SUNGLASS: A Weak-lensing Simulation Pipeline

    NASA Astrophysics Data System (ADS)

    Kiessling, Alina; Taylor, A.; Heavens, A.; Rhodes, J.; Bartlett, J.

    2013-01-01

    Weak gravitational lensing analysis is a powerful tool to investigate the dark Universe. Next generation weak-lensing telescope surveys (e.g. Euclid and WFIRST) promise to determine the equation of state of dark energy to 1% as well as probing the possibilities of extra dimensional gravity models and alternative cosmologies. To realize the potential of these new telescope surveys and to test new weak-lensing analysis techniques, challenges must be met. To achieve the small statistical errors required, experiments require full end-to-end simulations of huge volumes, which also probe the non-linear regime to assist in understanding the limitations of the analysis techniques. We have developed a new cosmic shear analysis pipeline SUNGLASS (Simulated UNiverses for Gravitational Lensing Analysis and Shear Surveys) that rapidly generates cosmic shear and convergence catalogues using N-body simulations. In this poster, I introduce the SUNGLASS pipeline and show how the SUNGLASS mock shear catalogues can be used in preparation for upcoming telescope missions and for analysis of existing observational data sets.

  17. 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.

  18. 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

  19. Nanometric thermal fluctuations of weakly confined biomembranes measured with microsecond time-resolution.

    PubMed

    Monzel, Cornelia; Schmidt, Daniel; Seifert, Udo; Smith, Ana-Sunčana; Merkel, Rudolf; Sengupta, Kheya

    2016-05-25

    We probe the bending fluctuations of bio-membranes using highly deflated giant unilamellar vesicles (GUVs) bound to a substrate by a weak potential arising from generic interactions. The substrate is either homogeneous, with GUVs bound only by the weak potential, or is chemically functionalized with a micro-pattern of very strong specific binders. In both cases, the weakly adhered membrane is seen to be confined at a well-defined distance above the surface while it continues to fluctuate strongly. We quantify the fluctuations of the weakly confined membrane at the substrate proximal surface as well as of the free membrane at the distal surface of the same GUV. This strategy enables us to probe in detail the damping of fluctuations in the presence of the substrate, and to independently measure the membrane tension and the strength of the generic interaction potential. Measurements were done using two complementary techniques - dynamic optical displacement spectroscopy (DODS, resolution: 20 nm, 10 μs), and dual wavelength reflection interference contrast microscopy (DW-RICM, resolution: 4 nm, 50 ms). After accounting for the spatio-temporal resolution of the techniques, an excellent agreement between the two measurements was obtained. For both weakly confined systems we explore in detail the link between fluctuations on the one hand and membrane tension and the interaction potential on the other hand. PMID:27142463

  20. Upgrading coke strength by a coal-blend-compaction process

    SciTech Connect

    Fun, F.; Brayton, W.E.; Shoenberger, R.W.

    1981-01-01

    In the continuing effort to upgrade the strength of coke made from available coal blends, US Steel is developing coal-blend compaction as an alternative method to coal preheating. In this process the coal blend is compacted to produce relatively weak compacted materials, which are subsequently degraded into controlled size fractions of intimately integrated particles of the multicomponent coal blend. The degraded blend particles are charged into conventional coke ovens for coking. Coal-blend-compaction tests conducted in the laboratory with coals from the Appalachian basin showed substantial improvement in coke strength. The encouraging laboratory results dictated a commerical scale test at US Steel's Gary Works. This plant test, in which more than 200 tons of coal blend was used, further confirmed the improvement in coke strength by the coal-blend-compaction process. Potential benefits of the process include (1) retrospective adaptation to existing coke batteries, (2) improved strength of coke from regular coal blends, (3) maintenance of same or higher coke strength with poor coal blends, and (4) economics that are competitive with or better than those of coal preheating. Continuing developments are being investigated in a compaction pilot plant and commercial coke ovens at US Steel's Clairton Works, mainly to establish engineering criteria and optimal controls for large-scale installations. 9 figures, 2 tables.

  1. Size and heterogeneity effects on the strength of fibrous composites

    NASA Astrophysics Data System (ADS)

    Mahesh, Sivasambu; Beyerlein, Irene J.; Phoenix, S. Leigh

    Probabilistic fiber composite strength distributions and size scalings depend heavily on both the stress redistribution mechanism around broken fibers and properties of the fiber strength distribution. In this study we perform large scale Monte Carlo simulations to study the fracture process in a fiber composite material in which fibers are arranged in parallel in a hexagonal array and their strengths are given by a two-parameter Weibull distribution function. To calculate the stress redistribution due to several broken fibers, a realistic 3D shear-lag theory is applied to rhombus-shaped domains with periodic boundary conditions. Empirical composite strength distributions are generated from several hundred Monte Carlo replications, particularly for much lower values of fiber Weibull modulus γ, and larger composite sizes than studied previously. Despite the localized stress enhancements due to fiber failures, predicted by the shear-lag model, composite response displays a transition to equal load sharing like behavior for approximately γ≤1. Accordingly, the results reveal distinct alterations in size effect, failure mode, and weak-link scaling behavior, associated with a transition from stress-driven to fiber strength-driven breakdown.

  2. 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

  3. Contraction of weak polyelectrolyte multilayers in response to organic solvents.

    PubMed

    Gu, Yuanqing; Ma, Yubing; Vogt, Bryan D; Zacharia, Nicole S

    2016-02-14

    Weak polyelectrolyte multilayers (PEMs) prepared by the layer-by-layer assembly technique have recently been found to demonstrate a unique contraction upon exposure to organic solvents. This response is dependent upon which organic solvent is employed, and fundamental questions have not been clarified regarding the correlation of the magnitude of the film contraction with solvent type. In this work, we used solubility parameters to analyze the response of branched poly(ethylene imine)/poly(acrylic acid) (BPEI/PAA) multilayers when exposed to a variety of solvents. BPEI/PAA multilayers were immersed in a series of 16 different organic solvents and solvent mixtures. Immersion in organic solvent caused film dehydration and therefore contraction and also induced changes in the mechanical properties of PEMs. The film thickness was the best predictor of how a film swelled in water or contracted in organic solvent when using different batches of commercially available polyelectrolytes, rather than polyelectrolyte assembly pH conditions. The degree of film contraction was correlated with Hansen and Kamlet-Taft solubility parameters as well as solvent dielectric constant. In most cases, the hydrogen bonding ability of solvents is the primary factor to determine the magnitude of film contraction. For these solvents, increasing the temperature which corresponds to decreasing the strength of hydrogen bonding, also decreases the ability to dehydrate the films. For solvents that do not follow these trends with the strength of hydrogen bonding, a stronger correlation was found between contraction and dielectric constant, indicating that both traditional solvent quality arguments and electrostatics are important to understanding the contraction of PEMs in organic solvents. PMID:26699080

  4. Weakly nonlinear analysis of impulsively-forced Faraday waves.

    PubMed

    Catllá, Anne; Porter, Jeff; Silber, Mary

    2005-11-01

    Parametrically-excited surface waves, forced by a repeating sequence of delta-function impulses, are considered within the framework of the Zhang-Viñals model [W. Zhang and J. Viñals, J. Fluid Mech. 336, 301 (1997)]. With impulsive forcing, the linear stability analysis can be carried out exactly and leads to an implicit equation for the neutral stability curves. As noted previously [J. Bechhoefer and B. Johnson, Am. J. Phys. 64, 1482 (1996)], in the simplest case of N=2 equally-spaced impulses per period (which alternate up and down) there are only subharmonic modes of instability. The familiar situation of alternating subharmonic and harmonic resonance tongues emerges only if an asymmetry in the spacing between the impulses is introduced. We extend the linear analysis for N=2 impulses per period to the weakly nonlinear regime, where we determine the leading order nonlinear saturation of one-dimensional standing waves as a function of forcing strength. Specifically, an analytic expression for the cubic Landau coefficient in the bifurcation equation is derived as a function of the dimensionless spacing between the two impulses and the fluid parameters that appear in the Zhang-Viñals model. As the capillary parameter is varied, one finds a parameter regime of wave amplitude suppression, which is due to a familiar 1:2 spatiotemporal resonance between the subharmonic mode of instability and a damped harmonic mode. This resonance occurs for impulsive forcing even when harmonic resonance tongues are absent from the neutral stability curves. The strength of this resonance feature can be tuned by varying the spacing between the impulses. This finding is interpreted in terms of a recent symmetry-based analysis of multifrequency forced Faraday waves [J. Porter, C. M. Topaz, and M. Silber, Phys. Lett. 93, 034502 (2004); C. M. Topaz, J. Porter, and M. Silber, Phys. Rev. E 70, 066206 (2004)]. PMID:16383732

  5. The Change of Grip Strength in a Patient with Congenital Myotonic Dystrophy Over a 4-year Period

    PubMed Central

    Kozuka, Naoki; Uchida, Eiji; Ninomiya, Takafumi; Tatsumi, Haruyuki; Takeda, Hidekatsu; Tachi, Nobutada

    2008-01-01

    Myotonic dystrophy (MyD) is a neuromuscular disease that is autosomal dominant and the most common form of muscular dystrophy affecting adults. The clinical features of MyD include a multisystemic disorder characterized by myotonia, progressive muscle weakness and wasting, cataracts, premature balding and mental retardation. The most severe type of MyD is classified as congenital MyD (CMyD). The muscle weakness in CMyD is very severe, but muscle development can be observed in the period of growth. However, no clinical case of this type has been reported yet. Therefore, we report on a girl with CMyD who had an increase in muscle strength over a four-year period. The girl with CMyD participated in this study from the age of 9 to the age of 12. The measurement of muscle strength was recorded as the maximum score of grip strength with the use of dynamometers. Grip strength was assessed once a year by the same two physical therapists. Grip strength of CMyD for each year was markedly weak when compared with the normal controls, but muscle strength changed within some specific growth areas. The muscle weakness in CMyD was remarkable, but the result showed that specific muscle strength of CMyD in childhood was actually increased. PMID:25792886

  6. Inheritance of pre-existing weakness in continental breakup: 3D numerical modeling

    NASA Astrophysics Data System (ADS)

    Liao, Jie; Gerya, Taras

    2013-04-01

    The whole process of continental rifting to seafloor spreading is one of the most important plate tectonics on the earth. There are many questions remained related to this process, most of which are poorly understood, such as how continental rifting transformed into seafloor spreading? How the curved oceanic ridge developed from a single straight continental rift? How the pre-existing weakness in either crust or lithospheric mantle individually influences the continental rifting and oceanic spreading? By employing the state-of-the-art three-dimensional thermomechanical-coupled numerical code (using Eulerian-Lagrangian finite-difference method and marker-in-cell technic) (Gerya and Yuen, 2007), which can model long-term plate extension and large strains, we studied the whole process of continental rifting to seafloor spreading based on the following question: How the pre-existing lithospheric weak zone influences the continental breakup? Continental rifts do not occur randomly, but like to follow the pre-existing weakness (such as fault zones, suture zones, failed rifts, and other tectonic boundaries) in the lithosphere, for instance, the western branch of East African Rift formed in the relatively weak mobile belts along the curved western border of Tanzanian craton (Corti et al., 2007; Nyblade and Brazier, 2002), the Main Ethiopian Rift developed within the Proterozoic mobile belt which is believed to represent a continental collision zone (Keranen and Klemperer, 2008),the Baikal rift formed along the suture between Siberian craton and Sayan-Baikal folded belt (Chemenda et al., 2002). The early stage formed rift can be a template for the future rift development and continental breakup (Keranen and Klemperer, 2008). Lithospheric weakness can either reduce the crustal strength or mantle strength, and leads to the crustal or mantle necking (Dunbar and Sawyer, 1988), which plays an important role on controlling the continental breakup patterns, such as controlling the

  7. 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.

  8. Clinical significance of severe isolated diaphragm weakness.

    PubMed

    Laroche, C M; Carroll, N; Moxham, J; Green, M

    1988-10-01

    We studied six patients with isolated bilateral paralysis or severe weakness of the diaphragm, present for 2 to 60 months (mean = 25), to document the clinical and respiratory sequelae of the condition. Severe diaphragm dysfunction was confirmed by the demonstration of the very low maximal transdiaphragmatic pressure (Pdi) generated by either a sniff (13 +/- 6 cm H2O, normal 148 +/- 24) or a static inspiration (11 +/- 8, normal 108 +/- 30) and during bilateral phrenic nerve stimulation (0.8 +/- 2.0, normal 22 +/- 4). Resting arterial blood gases were normal (SaO2 = 95 to 97%) and no oxygen desaturation occurred during maximal exercise on a treadmill. Maximum voluntary ventilation was low and related to PImax (r = 0.89). Overnight sleep monitoring showed that time spent in rapid eye movement sleep was normal (mean 55 +/- 36 min, range 26 to 117 min). Mean maximum increment in transcutaneous CO2 was within normal limits (6 +/- 2 mm Hg, range 3 to 9 mm Hg). Three patients had occasional brief episodes of oxygen desaturation (mean maximal decrease 13 +/- 10%, range 2 to 27%); however, only two of these spent a measurable proportion of total sleep time (TST) with an SaO2 of less than 80% (1% and 3% TST, respectively). No patient has developed any symptoms of nocturnal hypoventilation or chronic respiratory failure during periods of observation of up to five yr. We conclude that bilateral paralysis or very severe weakness of the diaphragm does not of itself lead to respiratory failure unless weakness of other respiratory muscles is present. PMID:3202460

  9. 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.

  10. Lossy compression of weak lensing data

    DOE PAGESBeta

    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

  11. Localization of weakly interacting Bose gas in quasiperiodic potential

    NASA Astrophysics Data System (ADS)

    Ray, Sayak; Pandey, Mohit; Ghosh, Anandamohan; Sinha, Subhasis

    2016-01-01

    We study the localization properties of weakly interacting Bose gas in a quasiperiodic potential. The Hamiltonian of the non-interacting system reduces to the well known ‘Aubry-André model’, which shows the localization transition at a critical strength of the potential. In the presence of repulsive interaction we observe multi-site localization and obtain a phase diagram of the dilute Bose gas by computing the superfluid fraction and the inverse participation ratio. We construct a low-dimensional classical Hamiltonian map and show that the onset of localization is manifested by the chaotic phase space dynamics. The level spacing statistics also identify the transition to localized states resembling a Poisson distribution that are ubiquitous for both non-interacting and interacting systems. We also study the quantum fluctuations within the Bogoliubov approximation and compute the quasiparticle energy spectrum. Enhanced quantum fluctuation and multi-site localization phenomenon of non-condensate density are observed above the critical coupling of the potential. We briefly discuss the effect of the trapping potential on the localization of matter wave.

  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. Gravitational Thermodynamics for Interstellar Gas and Weakly Degenerate Quantum Gas

    NASA Astrophysics Data System (ADS)

    Zhu, Ding Yu; Shen, Jian Qi

    2016-03-01

    The temperature distribution of an ideal gas in gravitational fields has been identified as a longstanding problem in thermodynamics and statistical physics. According to the principle of entropy increase (i.e., the principle of maximum entropy), we apply a variational principle to the thermodynamical entropy functional of an ideal gas and establish a relationship between temperature gradient and gravitational field strength. As an illustrative example, the temperature and density distributions of an ideal gas in two simple but typical gravitational fields (i.e., a uniform gravitational field and an inverse-square gravitational field) are considered on the basis of entropic and hydrostatic equilibrium conditions. The effect of temperature inhomogeneity in gravitational fields is also addressed for a weakly degenerate quantum gas (e.g., Fermi and Bose gas). The present gravitational thermodynamics of a gas would have potential applications in quantum fluids, e.g., Bose-Einstein condensates in Earth’s gravitational field and the temperature fluctuation spectrum in cosmic microwave background radiation.

  15. Detecting and visualizing weak signatures in hyperspectral data

    NASA Astrophysics Data System (ADS)

    MacPherson, Duncan James

    This thesis evaluates existing techniques for detecting weak spectral signatures from remotely sensed hyperspectral data. Algorithms are presented that successfully detect hard-to-find 'mystery' signatures in unknown cluttered backgrounds. The term 'mystery' is used to describe a scenario where the spectral target and background endmembers are unknown. Sub-Pixel analysis and background suppression are used to find deeply embedded signatures which can be less than 10% of the total signal strength. Existing 'mystery target' detection algorithms are derived and compared. Several techniques are shown to be superior both visually and quantitatively. Detection performance is evaluated using confidence metrics that are developed. A multiple algorithm approach is shown to improve detection confidence significantly. Although the research focuses on remote sensing applications, the algorithms presented can be applied to a wide variety of diverse fields such as medicine, law enforcement, manufacturing, earth science, food production, and astrophysics. The algorithms are shown to be general and can be applied to both the reflective and emissive parts of the electromagnetic spectrum. The application scope is a broad one and the final results open new opportunities for many specific applications including: land mine detection, pollution and hazardous waste detection, crop abundance calculations, volcanic activity monitoring, detecting diseases in food, automobile or airplane target recognition, cancer detection, mining operations, extracting galactic gas emissions, etc.

  16. Weakness in pregnancy – expect the unexpected

    PubMed Central

    Furara, S; Maw, M; Khan, F; Powell, K

    2008-01-01

    Guillain-Barré syndrome (GBS) is rare in pregnancy with an incidence estimated to be between 1.2 and 1.9 cases per 100,000 people annually, and it is generally accepted that it carries a high maternal risk. Delayed diagnosis is common because the initial non-specific symptoms may mimic changes in pregnancy. GBS should be considered in any pregnant patient complaining of muscle weakness, general malaise, tingling of the fingers and respiratory discomfort. This case aims to highlight the importance of early diagnosis, allowing prompt initiation of the immunomodulatory treatments which have been shown to improve outcome alongside multidisciplinary care.

  17. 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.

  18. 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.

  19. Relaxation properties of weakly coupled classical systems

    SciTech Connect

    Romero-Rochin, V.; Oppenheim, I.

    1988-10-01

    The relaxation properties of a small classical system weakly coupled to a large classical system which acts as a heat bath are described using a generalized Fokker-Planck equation. The Fokker-Planck equation is derived in general using a modification of the elimination of fast variables techniques previously described. The specific example in which the small system is a harmonic oscillator linearly coupled to the heat bath is treated in detail and it is demonstrated that there is a dynamic frequency shift as well as a statistical shift of the oscillator frequency.

  20. Hollow vortices in weakly compressible flows

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Vikas; Crowdy, Darren

    2014-11-01

    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.

  1. 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.

  2. 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.

  3. 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.

  4. PLASMA EMISSION BY WEAK TURBULENCE PROCESSES

    SciTech Connect

    Ziebell, L. F.; Gaelzer, R.; Yoon, P. H.; Pavan, J. E-mail: rudi.gaelzer@ufrgs.br E-mail: joel.pavan@ufpel.edu.br

    2014-11-10

    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.

  5. Water distribution in multilayers of weak polyelectrolytes.

    PubMed

    Tanchak, Oleh M; Yager, Kevin G; Fritzsche, Helmut; Harroun, Thad; Katsaras, John; Barrett, Christopher J

    2006-05-23

    The water localization in thin polyelectrolyte multilayers assembled from poly(acrylic acid) and poly(allylamine hydrochloride) was investigated with neutron reflectivity in an atmosphere of controlled humidity and with bulk water. Water was found to be distributed asymmetrically within the multilayer and to localize preferentially at the polymer surface. The diffusion of water into the multilayer did not completely penetrate to the substrate, but instead there appeared to be an exclusion zone near the Si substrate. These results help to explain previous observations of anomalous water transport kinetics in weak polyelectrolyte systems. PMID:16700605

  6. 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.

  7. 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.

  8. 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.

  9. Chaotic system detection of weak seismic signals

    NASA Astrophysics Data System (ADS)

    Li, Y.; Yang, B. J.; Badal, J.; Zhao, X. P.; Lin, H. B.; Li, R. L.

    2009-09-01

    When the signal-to-noise (S/N) ratio is less than -3 dB or even 0 dB, seismic events are generally difficult to identify from a common shot record. To overcome this type of problem we present a method to detect weak seismic signals based on the oscillations described by a chaotic dynamic system in phase space. The basic idea is that a non-linear chaotic oscillator is strongly immune to noise. Such a dynamic system is less influenced by noise, but it is more sensitive to periodic signals, changing from a chaotic state to a large-scale periodic phase state when excited by a weak signal. With the purpose of checking the possible contamination of the signal by noise, we have performed a numerical experiment with an oscillator controlled by the Duffing-Holmes equation, taking a distorted Ricker wavelet sequence as input signal. In doing so, we prove that the oscillator system is able to reach a large-scale periodic phase state in a strong noise environment. In the case of a common shot record with low S/N ratio, the onsets reflected from a same interface are similar to one other and can be put on a single trace with a common reference time and the periodicity of the so-generated signal follows as a consequence of moveout at a particular scanning velocity. This operation, which is called `horizontal dynamic correction' and leads to a nearly periodic signal, is implemented on synthetic wavelet sequences taking various sampling arrival times and scanning velocities. Thereafter, two tests, both in a noisy ambient of -3.7 dB, are done using a chaotic oscillator: the first demonstrates the capability of the method to really detect a weak seismic signal; the second takes care of the fundamental weakness of the dynamic correction coming from the use of a particular scanning velocity, which is investigated from the effect caused by near-surface lateral velocity variation on the periodicity of the reconstructed seismic signal. Finally, we have developed an application of the

  10. 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

  11. Structure and tie strengths in mobile communication networks.

    PubMed

    Onnela, J-P; Saramäki, J; Hyvönen, J; Szabó, G; Lazer, D; Kaski, K; Kertész, J; Barabási, A-L

    2007-05-01

    Electronic databases, from phone to e-mails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure of a society-wide communication network. We observe a coupling between interaction strengths and the network's local structure, with the counterintuitive consequence that social networks are robust to the removal of the strong ties but fall apart after a phase transition if the weak ties are removed. We show that this coupling significantly slows the diffusion process, resulting in dynamic trapping of information in communities and find that, when it comes to information diffusion, weak and strong ties are both simultaneously ineffective. PMID:17456605

  12. Equilibrium Configuration in a Nematic Liquid Crystal Droplet with Homeotropic Anchoring of Finite Strength

    NASA Astrophysics Data System (ADS)

    Kanke, Masaki; Sasaki, Kazuo

    2013-09-01

    Equilibrium configuration of order parameter in a nematic liquid crystal droplet with homeotropic anchoring of finite strength at the surface is studied numerically by using the Landau--de Gennes approach. It is found that a hedgehog-like configuration with a disclination loop of a small radius is stable for strong anchoring while an axial configuration without defect is stable for weak anchoring. A first-order phase transition from one configuration to the other occurs as the strength of the anchoring is varied. The critical anchoring strength turns out to increase almost linearly with the inverse of the droplet radius.

  13. Rock strength along a fluvial transect of the Colorado Plateau - quantifying a fundamental control on geomorphology

    NASA Astrophysics Data System (ADS)

    Bursztyn, N.; Pederson, J. L.; Tressler, C.; Mackley, R. D.; Mitchell, K. J.

    2015-11-01

    Bedrock strength is a key parameter that influences slope stability, landscape erosion, and fluvial incision. Yet, it is often ignored or indirectly constrained in studies of landscape evolution, as with the K erodibility parameter in stream-power models. Empirical datasets of rock strength suited to address geomorphic questions are rare, in part because of the difficulty in measuring those rocks at Earth's surface that are heterolithic, weak, or poorly exposed. Here we present a large dataset of measured bedrock strength organized by rock units exposed along the length of the trunk Green-Colorado River through the iconic Colorado Plateau of the western U.S. Measurements include field compressive tests, fracture spacing, and Selby Rock Mass Strength at 168 localities, as well as 672 individual tensile-strength tests in the laboratory. Tensile strength results are compared to geomorphic metrics of unit stream power, river gradient, and channel and valley-bottom width through the arid Colorado Plateau, where the influence of bedrock is intuitive but unquantified. Our dataset reveals logical trends between tensile and compressive strength as well as between strength, rock type and age. In bedrock reaches of the fluvial transect, there is a positive rank-correlation and a strong power-law correlation between reach-averaged rock strength and unit stream power, as well as a linear relation between tensile strength and river gradient. Expected relations between fracture spacing and topography are masked partly by the massive yet weak sandstones in the dataset. To constrain values for weak rock types such as shale, we utilize the inverse power-law scaling between tensile strength and valley-bottom width to estimate their "effective" tensile strength. Results suggest that tensile strength varies to at least an order-of-magnitude smaller values than evident with directly testable rocks in this landscape, and values for erodibility (K) in numerical simulations may be informed

  14. Magnetite in human tissues: A mechanism for the biological effects of weak ELF magnetic fields

    SciTech Connect

    Kirschvink, J.L.; Kobayashi-Kirschvink, A.; Diaz-Ricci, J.C.; Kirschvink, S.J. )

    1992-01-01

    Due to the apparent lack of a biophysical mechanism, the question of whether weak, low-frequency magnetic fields are able to influence living organisms has long been one of the most controversial subjects in any field of science. However, two developments during the past decade have changed this perception dramatically, the first being the discovery that many organisms, including humans, biochemically precipitate the ferrimagnetic mineral magnetite (Fe3O4). In the magnetotactic bacteria, the geomagnetic response is based on either biogenic magnetite or greigite (Fe3S4), and reasonably good evidence exists that this is also the case in higher animals such as the honey bee. Second, the development of simple behavioral conditioning experiments for training honey bees to discriminate magnetic fields demonstrates conclusively that at least one terrestrial animal is capable of detecting earth-strength magnetic fields through a sensory process. In turn, the existence of this ability implies the presence of specialized receptors which interact at the cellular level with weak magnetic fields in a fashion exceeding thermal noise. A simple calculation shows that magnetosomes moving in response to earth-strength ELF fields are capable of opening trans-membrane ion channels, in a fashion similar to those predicted by ionic resonance models. Hence, the presence of trace levels of biogenic magnetite in virtually all human tissues examined suggests that similar biophysical processes may explain a variety of weak field ELF bioeffects. 61 refs.

  15. Respiratory muscle activity and oxygenation during sleep in patients with muscle weakness.

    PubMed

    White, J E; Drinnan, M J; Smithson, A J; Griffiths, C J; Gibson, G J

    1995-05-01

    Patients with respiratory muscle weakness show nocturnal hypoventilation, with oxygen desaturation particularly during rapid eye movement (REM) sleep, but evidence in individuals with isolated bilateral diaphragmatic paresis (BDP) is conflicting. The effect of sleep on relative activity of the different respiratory muscles of such patients and, consequently, the precise mechanisms causing desaturation have not been clarified. We have studied eight patients, four with generalized muscle weakness and four with isolated BDP during nocturnal sleep with measurements including oxygen saturation and surface electromyographic (EMG) activity of various respiratory muscle groups. Nocturnal oxygenation correlated inversely with postural fall in vital capacity, an index of diaphragmatic strength. During REM sleep, hypopnoea and desaturation occurred particularly during periods of rapid eye movements (phasic REM sleep). In most subjects, such events were "central" in type and associated with marked suppression of intercostal muscle activity, but two subjects had recurrent desaturation due to "obstructive" hypopnoea and/or apnoea. Expiratory activity of the external oblique muscle was present whilst awake and during non-rapid eye movement (NREM) sleep in seven of the eight subjects in the semirecumbent posture. This probably represents an "accessory inspiratory" effect, which aids passive caudal diaphragmatic motion as the abdominal muscles relax at the onset of inspiration. Expiratory abdominal muscle activity was suppressed in phasic REM sleep, suggesting that loss of this "accessory inspiratory" effect may contribute to "central" hypopnoea. We conclude that, in patients with muscle weakness, nocturnal oxygenation correlates with diaphragmatic strength.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7656954

  16. The Consequences of Differentiation in Episodic Memory: Similarity and the Strength Based Mirror Effect

    ERIC Educational Resources Information Center

    Criss, Amy H.

    2006-01-01

    When items on one list receive more encoding than items on another list, the improvement in performance usually manifests as an increase in the hit rate and a decrease in the false alarm rate (FAR). A common account of this strength based mirror effect is that participants adopt a more strict criterion following a strongly than weakly encoded list…

  17. Weak compressibility of surface wave turbulence

    NASA Astrophysics Data System (ADS)

    Vucelja, Marija; Fouxon, Itzhak; Falkovich, Gregory

    2010-11-01

    Clustering of matter on the surface of lakes and pools and of oil slicks and seaweed on the sea surface is well-known empirically but there is no theory that describes it. Since surface flows are always compressible, such a theory should be based on the description of the development of density of inhomogeneities in a compressible flow. We studied the growth of small-scale inhomogeneities in the density of particles floating in weakly nonlinear small-amplitude surface waves. Despite the small amplitude, the accumulated effect of the long-time evolution may produce a strongly inhomogeneous distribution of the floaters: density fluctuations grow exponentially with a small but finite exponent. We have shown that the exponent is of sixth or higher order in wave amplitude. As a result, the inhomogeneities do not form within typical time scales of the natural environment. Thus the turbulence of surface waves is weakly compressible and alone it cannot be a realistic mechanism of the clustering of matter on liquid surfaces. However if besides waves there are also currents, the interplay of waves with currents, might be in some cases responsible for the patchiness of the floaters.

  18. Optimizing Average Precision Using Weakly Supervised Data.

    PubMed

    Behl, Aseem; Mohapatra, Pritish; Jawahar, C V; Kumar, M Pawan

    2015-12-01

    Many tasks in computer vision, such as action classification and object detection, require us to rank a set of samples according to their relevance to a particular visual category. The performance of such tasks is often measured in terms of the average precision (ap). Yet it is common practice to employ the support vector machine ( svm) classifier, which optimizes a surrogate 0-1 loss. The popularity of svmcan be attributed to its empirical performance. Specifically, in fully supervised settings, svm tends to provide similar accuracy to ap-svm, which directly optimizes an ap-based loss. However, we hypothesize that in the significantly more challenging and practically useful setting of weakly supervised learning, it becomes crucial to optimize the right accuracy measure. In order to test this hypothesis, we propose a novel latent ap-svm that minimizes a carefully designed upper bound on the ap-based loss function over weakly supervised samples. Using publicly available datasets, we demonstrate the advantage of our approach over standard loss-based learning frameworks on three challenging problems: action classification, character recognition and object detection. PMID:26539857

  19. 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.

  20. 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

  1. A model of weak viscoelastic nematodynamics

    NASA Astrophysics Data System (ADS)

    Leonov, Arkady I.

    2008-03-01

    The paper develops a continuum theory of weak viscoelastic nematodynamics of Maxwell type. It can describe the molecular elasticity effects in mono-domain flows of liquid crystalline polymers as well as the viscoelastic effects in suspensions of uniaxially symmetric particles in polymer fluids. Along with viscoelastic and nematic kinematics, the theory employs a general form of weakly elastic thermodynamic potential and the Leslie Ericksen Parodi type constitutive equations for viscous nematic liquids, while ignoring inertia effects and the Frank (orientation) elasticity in liquid crystal polymers. In general case, even the simplest Maxwell model has many basic parameters. Nevertheless, recently discovered algebraic properties of nematic operations reveal a general structure of the theory and present it in a simple form. It is shown that the evolution equation for director is also viscoelastic. An example of magnetization exemplifies the action of non-symmetric stresses. When the magnetic field is absent, the theory is reduced to the symmetric, fluid mechanical case with relaxation properties for both the stress and director. Our recent analyses of elastic and viscous soft deformation modes are also extended to the viscoelastic case. The occurrence of possible soft modes minimizes both the free energy and dissipation, and also significantly decreases the number of material parameters. In symmetric linear case, the theory is explicitly presented in terms of anisotropic linear memory functionals. Several analytical results demonstrate a rich behavior predicted by the developed model for steady and unsteady flows in simple shearing and simple elongation.

  2. 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.

  3. 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.

  4. Optimal Weak-Lensing Skewness Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Tong-Jie; Pen, Ue-Li; Zhang, Pengjie; Dubinski, John

    2003-12-01

    Weak-lensing measurements are starting to provide statistical maps of the distribution of matter in the universe that are increasingly precise and complementary to cosmic microwave background maps. The most common measurement is the correlation in alignments of background galaxies, which can be used to infer the variance of the projected surface density of matter. This measurement of the fluctuations is insensitive to the total mass content and is analogous to using waves on the ocean to measure its depths. However, when the depth is shallow, as happens near a beach, waves become skewed. Similarly, a measurement of skewness in the projected matter distribution directly measures the total matter content of the universe. While skewness has already been convincingly detected, its constraint on cosmology is still weak. We address optimal analyses for the Canada-France-Hawaii Telescope Legacy Survey in the presence of noise. We show that a compensated Gaussian filter with a width of 2.5‧ optimizes the cosmological constraint, yielding ΔΩm/Ωm~10%. This is significantly better than other filters that have been considered in the literature. This can be further improved with tomography and other sophisticated analyses.

  5. 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.

  6. Ideal tensile strength of B2 transition-metal aluminides

    NASA Astrophysics Data System (ADS)

    Li, Tianshu; Morris, J. W., Jr.; Chrzan, D. C.

    2004-08-01

    The ideal tensile strengths of the B2 -type (CsCl) transition-metal aluminides FeAl , CoAl , and NiAl have been investigated using an ab initio electronic structure total energy method. The three materials exhibit dissimilar mechanical behaviors under the simulated ideal tensile tests along [001], [110], and [111] directions. FeAl is weakest in tension along [001] whereas CoAl and NiAl are strongest in the same direction. The weakness of FeAl along [001] direction is attributed to the instability introduced by the filling of antibonding d states.

  7. The Strength of Friendship Ties in Proximity Sensor Data

    PubMed Central

    Sekara, Vedran; Lehmann, Sune

    2014-01-01

    Understanding how people interact and socialize is important in many contexts from disease control to urban planning. Datasets that capture this specific aspect of human life have increased in size and availability over the last few years. We have yet to understand, however, to what extent such electronic datasets may serve as a valid proxy for real life social interactions. For an observational dataset, gathered using mobile phones, we analyze the problem of identifying transient and non-important links, as well as how to highlight important social interactions. Applying the Bluetooth signal strength parameter to distinguish between observations, we demonstrate that weak links, compared to strong links, have a lower probability of being observed at later times, while such links—on average—also have lower link-weights and probability of sharing an online friendship. Further, the role of link-strength is investigated in relation to social network properties. PMID:24999984

  8. Evaluation of Respiratory Muscle Strength in Mouth Breathers: Clinical Evidences

    PubMed Central

    Andrade da Cunha, Renata; Andrade da Cunha, Daniele; Assis, Roberta Borba; Bezerra, Luciana Ângelo; Justino da Silva, Hilton

    2013-01-01

    Introduction The child who chronically breathes through the mouth may develop a weakness of the respiratory muscles. Researchers and clinical are seeking for methods of instrumental evaluation to gather complementary data to clinical evaluations. With this in mind, it is important to evaluate breathing muscles in the child with Mouth Breathing. Objective To develop a review to investigate studies that used evaluation methods of respiratory muscle strength in mouth breathers. Data Synthesis  The authors were unanimous in relation to manovacuometry method as a way to evaluate respiratory pressures in Mouth Breathing children. Two of them performed with an analog manovacuometer and the other one, digital. The studies were not evaluated with regard to the method efficacy neither the used instruments. Conclusion There are few studies evaluating respiratory muscle strength in Mouth Breathing people through manovacuometry and the low methodological rigor of the analyzed studies hindered a reliable result to support or refuse the use of this technique. PMID:25992108

  9. The strength of friendship ties in proximity sensor data.

    PubMed

    Sekara, Vedran; Lehmann, Sune

    2014-01-01

    Understanding how people interact and socialize is important in many contexts from disease control to urban planning. Datasets that capture this specific aspect of human life have increased in size and availability over the last few years. We have yet to understand, however, to what extent such electronic datasets may serve as a valid proxy for real life social interactions. For an observational dataset, gathered using mobile phones, we analyze the problem of identifying transient and non-important links, as well as how to highlight important social interactions. Applying the Bluetooth signal strength parameter to distinguish between observations, we demonstrate that weak links, compared to strong links, have a lower probability of being observed at later times, while such links-on average-also have lower link-weights and probability of sharing an online friendship. Further, the role of link-strength is investigated in relation to social network properties. PMID:24999984

  10. Duality of Weak and Strong Scatterer in Luttinger Liquid Coupled to Massless Bosons

    NASA Astrophysics Data System (ADS)

    Galda, Alexey; Yurkevich, Igor; Yevtushenko, Oleg; Lerner, Igor

    2013-03-01

    We study electronic transport in a Luttinger liquid (LL) with an embedded impurity, which is either a weak scatterer (WS) or a weak link (WL), when interacting electrons are coupled to one-dimensional massless bosons (e.g., acoustic phonons). The additional coupling competes with Coulomb interaction changing scaling exponents of various correlation functions. The impurity strength λ and the tunneling amplitude t in the WS and WL limits scale at low energies ɛ as: λ (ɛ) ~λ0ɛ Δws - 1 and t (ɛ) ~t0ɛ Δwl - 1 , correspondingly. We find that the duality relation between the scaling dimensions established for the standard LL, ΔwsΔwl = 1 , holds in the presence of the additional coupling for an arbitrary fixed strength of boson scattering from the impurity. As a result, at low temperatures the system remains either an ideal insulator or an ideal metal, regardless of the scattering strength. However, in the case when electron and boson scattering from the impurity are correlated, the system has a rich phase diagram that includes a metal-insulator transition at some intermediate values of the scattering. Leverhulme grant RPG-380, DFG through SFB TR-12, DoE Office of Science under the Contract No. DEAC02-06CH11357

  11. Weak ENSO asymmetry due to weak nonlinear air-sea interaction in CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Wang, Fan; Sun, De-Zheng

    2016-03-01

    State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities. Significantly weak ENSO asymmetry and weakly nonlinear air-sea interaction over the tropical Pacific was found in CMIP5 (Coupled Model Intercomparison Project, Phase 5) climate models compared with observation. The results suggest that a weak nonlinear air-sea interaction may play a role in the weak ENSO asymmetry. Moreover, a weak nonlinearity in air-sea interaction in the models may be associated with the biases in the mean climate—the cold biases in the equatorial central Pacific. The excessive cold tongue bias pushes the deep convection far west to the western Pacific warm pool region and suppresses its development in the central equatorial Pacific. The deep convection has difficulties in further moving to the eastern equatorial Pacific, especially during extreme El Ni˜no events, which confines the westerly wind anomaly to the western Pacific. This weakens the eastern Pacific El Ni˜no events, especially the extreme El Ni˜no events, and thus leads to the weakened ENSO asymmetry in climate models. An accurate mean state structure (especially a realistic cold tongue and deep convection) is critical to reproducing ENSO events in climate models. Our evaluation also revealed that ENSO statistics in CMIP5 climate models are slightly improved compared with those of CMIP3. The weak ENSO asymmetry in CMIP5 is closer to the observation. It is more evident in CMIP5 that strong ENSO activities are usually accompanied by strong ENSO asymmetry, and the diversity of ENSO amplitude is reduced.

  12. Crustal rheological strength heterogeneities control the formation of continental plateau margins

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Zhu, Bojing; Yang, Xiaolin

    2015-08-01

    The margins bordering the Tibetan Plateau show two end-member morphologies in topographic gradient: steep margins and low-gradient margins. To investigate the formation mechanism of convergent intracontinental plateau margins, we conduct 2D numerical experiments to simulate crustal deformation process across plateau margins. Our numerical experiments demonstrate that heterogeneities in crustal rheological strength control significantly the formation of plateau margins when subjected to crustal convergence. A very steep margin is the result of crustal convergence between plateau with weak lower crust and foreland basin with strong lower crust. By contrast, a low-gradient margin could result from crustal convergence between plateau and foreland with less strength contrast. This finding suggests that the diversity in topographic gradient along the Tibetan Plateau borders reflects heterogeneities in crustal rheological strength across the plateau margins. Steep gradient at the margins indicate large crustal rheological strength contrasts between the weak ductile lower crust of the Tibetan Plateau and its strong surrounding foreland basins, like the Sichuan Basin, the Tarim Basin and the Qaidam Basin. Beneath these steep margins the horizontal flow of the Tibetan ductile lower crust is inhibited and forced to extrude to support escarpments. Low-gradient at the margins indicate less crustal strength variations between the plateau and outer forelands, like at the northeastern and southeastern margins, where they might be outlets for the weak ductile Tibetan lower crust to flow away from the plateau.

  13. Baryons, neutrinos, feedback and weak gravitational lensing

    NASA Astrophysics Data System (ADS)

    Harnois-Déraps, Joachim; van Waerbeke, Ludovic; Viola, Massimo; Heymans, Catherine

    2015-06-01

    The effect of baryonic feedback on the dark matter mass distribution is generally considered to be a nuisance to weak gravitational lensing. Measurements of cosmological parameters are affected as feedback alters the cosmic shear signal on angular scales smaller than a few arcminutes. Recent progress on the numerical modelling of baryon physics has shown that this effect could be so large that, rather than being a nuisance, the effect can be constrained with current weak lensing surveys, hence providing an alternative astrophysical insight on one of the most challenging questions of galaxy formation. In order to perform our analysis, we construct an analytic fitting formula that describes the effect of the baryons on the mass power spectrum. This fitting formula is based on three scenarios of the OverWhelmingly Large hydrodynamical simulations. It is specifically calibrated for z < 1.5, where it models the simulations to an accuracy that is better than 2 per cent for scales k < 10 h Mpc-1 and better than 5 per cent for 10 < k < 100 h Mpc-1. Equipped with this precise tool, this paper presents the first constraint on baryonic feedback models using gravitational lensing data, from the Canada France Hawaii Telescope Lensing Survey (CFHTLenS). In this analysis, we show that the effect of neutrino mass on the mass power spectrum is degenerate with the baryonic feedback at small angular scales and cannot be ignored. Assuming a cosmology precision fixed by WMAP9, we find that a universe with massless neutrinos is rejected by the CFHTLenS lensing data with 85-98 per cent confidence, depending on the baryon feedback model. Some combinations of feedback and non-zero neutrino masses are also disfavoured by the data, although it is not yet possible to isolate a unique neutrino mass and feedback model. Our study shows that ongoing weak gravitational lensing surveys (KiDS, HSC and DES) will offer a unique opportunity to probe the physics of baryons at galactic scales, in

  14. Evaluating the strength of concrete structure on terrace houses

    NASA Astrophysics Data System (ADS)

    Hasbullah, Mohd. Amran; Yusof, Rohana; Rahman, Mohd Nazaruddin Yusoff @ Abdul

    2016-08-01

    The concrete structure is the main component to support the structure of the building, but when concrete has been used for an extended period hence, it needs to be evaluated to determine the current strength, durability and how long it can last. The poor quality of concrete structures will cause discomfort to the user and, the safety will be affected due to lack of concrete strength. If these issues are not monitored or not precisely known performance, and no further action done then, the concrete structure will fail and eventually it will collapse. Five units of terrace houses that are built less than 10 years old with extension or renovations and have cracks at Taman Samar Indah, Samarahan, Sarawak have been selected for this study. The instrument used in this research is Ultrasonic Pulse Velocity (UPV), with the objective to determine the current strength and investigate the velocity of a pulse at the concrete cracks. The data showed that the average velocity of the pulse is less than 3.0 km/s and has shown that the quality of the concrete in the houses too weak scale / doubt in the strength of concrete. It also indicates that these houses need to have an immediate repair in order to remain secure other concrete structures.

  15. UV exposure and the tensile strength of optical fiber

    NASA Astrophysics Data System (ADS)

    Sloan, Diann A.; Le Blanc, S. P.; Kane, Martin D.

    2001-04-01

    The tensile strength of fiber Bragg gratings is dependent on the type of UV laser exposure. The basic conclusion for the traditional method of producing gratings (exposure in the near-field region of a phase mask) is that the pulsed KrF excimer laser (248 nm) damages the fiber and the continuous wave frequency-doubled argon ion laser (244 nm) does not, provided that the fibers are handled carefully. Using the excimer laser at a low fluence (~5 mJ/cm2 pulse) and hydrogen loaded fiber, we demonstrate that Bragg gratings with an index change of 1.25x10-4 can be written. Although this index change is not enough to write a highly reflecting WDM grating, it is enough to write a weakly reflecting pump stabilization grating. The tensile strength of these fibers follow a Weibull distribution similar to pristine fiber with a median tensile strength of ~4.4 GPa (640 kpsi). A small percentage of the fibers are minimally damaged. As the fluence is increased, the median tensile strength decreases and the variability increases. The probability of damage from the laser as a function of the laser intensity suggests a damage mechanism related to laser-induced dielectric breakdown.

  16. BMP signaling and microtubule organization regulate synaptic strength

    PubMed Central

    Ball, Robin W.; Peled, Einat; Guerrero, Giovanna; Isacoff, Ehud Y.

    2015-01-01

    The strength of synaptic transmission between a neuron and multiple postsynaptic partners can vary considerably. We have studied synaptic heterogeneity using the glutamatergic Drosophila neuromuscular junction (NMJ), which contains multiple synaptic connections of varying strength between a motor axon and muscle fiber. In larval NMJs, there is a gradient of synaptic transmission from weak proximal to strong distal boutons. We imaged synaptic transmission with the postsynaptically targeted fluorescent calcium sensor SynapCam, to investigate the molecular pathways that determine synaptic strength and set up this gradient. We discovered that mutations in the Bone Morphogenetic Protein (BMP) signaling pathway disrupt production of strong distal boutons. We find that strong connections contain unbundled microtubules in the boutons, suggesting a role for microtubule organization in transmission strength. The spastin mutation, which disorganizes microtubules, disrupted the transmission gradient, supporting this interpretation. We propose that the BMP pathway, shown previously to function in the homeostatic regulation of synaptic growth, also boosts synaptic transmission in a spatially selective manner that depends on the microtubule system. PMID:25681521

  17. Managing Chemotherapy Side Effects: Fatigue (Feeling Weak and Very Tired)

    MedlinePlus

    ... ational C ancer I nstitute Managing Chemotherapy Side Effects Fatigue (Feeling weak and very tired) Why do ... manage or treat your fatigue. Managing Chemotherapy Side Effects: Fatigue (Feeling weak and very tired) Take time ...

  18. First results about recovery of walking function in patients with intensive care unit-acquired muscle weakness from the General Weakness Syndrome Therapy (GymNAST) cohort study

    PubMed Central

    Mehrholz, Jan; Mückel, Simone; Oehmichen, Frank; Pohl, Marcus

    2015-01-01

    Objectives To describe the time course of recovery of walking function and other activities of daily living in patients with intensive care unit (ICU)-acquired muscle weakness. Design This is a cohort study. Participants We included critically ill patients with ICU-acquired muscle weakness. Setting Post-acute ICU and rehabilitation units in Germany. Measures We measured walking function, muscle strength, activities in daily living, motor and cognitive function. Results We recruited 150 patients (30% female) who fulfilled our inclusion and exclusion criteria. The primary outcome recovery of walking function was achieved after a median of 28.5 days (IQR=45) after rehabilitation onset and after a median of 81.5 days (IQR=64) after onset of illness. Our final multivariate model for recovery of walking function included two clinical variables from baseline: the Functional Status Score ICU (adjusted HR=1.07 (95% CI 1.03 to 1.12) and the ability to reach forward in cm (adjusted HR=1.02 (95% CI 1.00 to 1.04). All secondary outcomes but not pain improved significantly in the first 8 weeks after study onset. Conclusions We found good recovery of walking function for most patients and described the recovery of walking function of people with ICU-acquired muscle weakness. Trials registrations number Sächsische Landesärztekammer EK-BR-32/13-1; DRKS00007181, German Register of Clinical Trials. PMID:26700274

  19. Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes.

    PubMed

    Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

    2012-06-01

    Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ∼70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired. PMID:22538869

  20. Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes

    NASA Astrophysics Data System (ADS)

    Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

    2012-05-01

    Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ~70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired.