Science.gov

Sample records for staggered work hours

  1. Ageing, working hours and work ability.

    PubMed

    Costa, G; Sartori, S

    2007-11-01

    The current paper reports the main results of several studies carried out on Italian workers using the work ability index as a complementary tool for workers' periodical health surveillance. The work ability index shows a general decreasing trend over the years, but it changes differently according to working conditions and personal health status. In jobs with higher mental involvement and autonomy, but lower physical constraint, it remains quite constant and high over the years, while it significantly decreases with a steeper trend the higher the physical work load and the lower the job control are. Sex and working hours appear to act concurrently in influencing work ability, particularly in association with more physically demanding jobs. It is therefore necessary to adopt flexible interventions, able to give ageing shift workers a proper support for maintaining a satisfactory work ability, by means of actions addressed both to work organization and psycho-physical conditions.

  2. Long Work Hours May Hurt Your Health

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_159479.html Long Work Hours May Hurt Your Health At the job ... at Ohio State University. The link between long work hours and disease ''seems to be present a ...

  3. 46 CFR 15.710 - Working hours.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Working hours. 15.710 Section 15.710 Shipping COAST... Limitations and Qualifying Factors § 15.710 Working hours. In addition to prescribing watch requirements, 46 U.S.C. 8104 sets limitations on the working hours of credentialed officers and crew...

  4. 29 CFR 783.46 - Hours worked.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...; and General Electric Co. v. Porter, 208 F. 2d 805, certiorari denied, 347 U.S. 951, 975) would be applicable in determining what time constitutes hours worked. See also the general discussion of hours worked... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  5. 29 CFR 783.46 - Hours worked.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; and General Electric Co. v. Porter, 208 F. 2d 805, certiorari denied, 347 U.S. 951, 975) would be applicable in determining what time constitutes hours worked. See also the general discussion of hours worked... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  6. 29 CFR 783.46 - Hours worked.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...; and General Electric Co. v. Porter, 208 F. 2d 805, certiorari denied, 347 U.S. 951, 975) would be applicable in determining what time constitutes hours worked. See also the general discussion of hours worked... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  7. 29 CFR 783.46 - Hours worked.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...; and General Electric Co. v. Porter, 208 F. 2d 805, certiorari denied, 347 U.S. 951, 975) would be applicable in determining what time constitutes hours worked. See also the general discussion of hours worked... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  8. 29 CFR 783.46 - Hours worked.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...; and General Electric Co. v. Porter, 208 F. 2d 805, certiorari denied, 347 U.S. 951, 975) would be applicable in determining what time constitutes hours worked. See also the general discussion of hours worked... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  9. Flexibility of working hours in the 24-hour society.

    PubMed

    Costa, G

    2006-01-01

    The 24-hour Society undergoes an ineluctable process towards a social organisation where time constraints are no more restricting human life. The borders between working and social times are no more fixed and rigidly determined, and the value of working time changes according to the different economic and social effects you may consider. Shift and night work, irregular and flexible working hours, together with new technologies, are the milestone of this epochal passage. What are the advantages and disadvantages for the individual, the companies, and the society? What is the cost/benefit ratio in terms of health and social well-being? Coping properly with this process means avoiding a passive acceptance of it with consequent maladjustments at both individual and social level, but adopting effective preventive and compensative strategies aimed at building up a more sustainable society. Flexible working times now appear to be one of the best ways to cope with the demands of the modern life, but there are different points of view about labour and temporal 'flexibility" between employers and employees. For the former it means a prompt adaptation to market demands and technological innovations; for the latter it is a way to improve working and social life, by decreasing work constraints and increasing control and autonomy. Although it can be easily speculated that individual-based 'flexibility" should improve health and well-being, and especially satisfaction, whereas company-based flexibility" might interfere negatively, the effective consequences on health and well-being have still to be analysed properly. PMID:17017360

  10. Accommodating to Restrictions on Residents' Working Hours.

    ERIC Educational Resources Information Center

    Foster, Henry W., Jr.; Seltzer, Vicki L.

    1991-01-01

    In response to New York State legislation limiting house staff working hours, a survey of obstetrics and gynecology resident programs (n=26) was conducted. Results were used to construct a prototype call schedule and a hypothetical monthly schedule indicating how a single resident would function without violating any state regulations. (MSE)

  11. How Hours of Work Affect Occupational Earnings.

    ERIC Educational Resources Information Center

    Hecker, David

    1998-01-01

    In most managerial, management-related, sales, production, and transportation occupations, workers with longer hours earned a high hourly rate. The reverse was true for some jobs, including computer specialists, engineers, schoolteachers, and construction workers. (JOW)

  12. 5 CFR 551.521 - Fractional hours of work.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Fractional hours of work. 551.521 Section... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Overtime Pay Provisions Fractional Hours of Work § 551.521 Fractional hours of work. (a) An employee shall be compensated for every minute of regular overtime work....

  13. 5 CFR 551.521 - Fractional hours of work.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Fractional hours of work. 551.521 Section... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Overtime Pay Provisions Fractional Hours of Work § 551.521 Fractional hours of work. (a) An employee shall be compensated for every minute of regular overtime work....

  14. 29 CFR 553.221 - Compensable hours of work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Compensable hours of work. (a) The general rules on compensable hours of work are set forth in 29 CFR part 785 which is applicable to employees for whom the section 7(k) exemption is claimed. Special rules for...

  15. 29 CFR 553.221 - Compensable hours of work.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Compensable hours of work. (a) The general rules on compensable hours of work are set forth in 29 CFR part 785 which is applicable to employees for whom the section 7(k) exemption is claimed. Special rules for...

  16. 29 CFR 553.221 - Compensable hours of work.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Compensable hours of work. (a) The general rules on compensable hours of work are set forth in 29 CFR part 785 which is applicable to employees for whom the section 7(k) exemption is claimed. Special rules for...

  17. 29 CFR 553.221 - Compensable hours of work.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Compensable hours of work. (a) The general rules on compensable hours of work are set forth in 29 CFR part 785 which is applicable to employees for whom the section 7(k) exemption is claimed. Special rules for...

  18. 29 CFR 553.221 - Compensable hours of work.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Compensable hours of work. (a) The general rules on compensable hours of work are set forth in 29 CFR part 785 which is applicable to employees for whom the section 7(k) exemption is claimed. Special rules for...

  19. 5 CFR 551.421 - Regular working hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Hours of Work Application of Principles in Relation to Other Activities § 551.421 Regular working hours. (a) Under the Act there is no requirement that a Federal employee... employees. In determining what activities constitute hours of work under the Act, there is generally...

  20. 5 CFR 551.421 - Regular working hours.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Hours of Work Application of Principles in Relation to Other Activities § 551.421 Regular working hours. (a) Under the Act there is no requirement that a Federal employee... employees. In determining what activities constitute hours of work under the Act, there is generally...

  1. 5 CFR 551.421 - Regular working hours.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Hours of Work Application of Principles in Relation to Other Activities § 551.421 Regular working hours. (a) Under the Act there is no requirement that a Federal employee... employees. In determining what activities constitute hours of work under the Act, there is generally...

  2. 5 CFR 551.421 - Regular working hours.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Hours of Work Application of Principles in Relation to Other Activities § 551.421 Regular working hours. (a) Under the Act there is no requirement that a Federal employee... employees. In determining what activities constitute hours of work under the Act, there is generally...

  3. Work-Family Conflict, Children, and Hour Mismatches in Australia

    ERIC Educational Resources Information Center

    Reynolds, Jeremy; Aletraris, Lydia

    2007-01-01

    This article helps integrate research on work hours and work-family issues by examining how work-family conflict is related to the desire for more and fewer hours of work. Using the first wave of the Household Income and Labor Dynamics in Australia survey, we find that work-to-family conflict is associated with a desire for fewer hours of work.…

  4. The working hours of hospital staff nurses and patient safety.

    PubMed

    Rogers, Ann E; Hwang, Wei-Ting; Scott, Linda D; Aiken, Linda H; Dinges, David F

    2004-01-01

    The use of extended work shifts and overtime has escalated as hospitals cope with a shortage of registered nurses (RNs). Little is known, however, about the prevalence of these extended work periods and their effects on patient safety. Logbooks completed by 393 hospital staff nurses revealed that participants usually worked longer than scheduled and that approximately 40 percent of the 5,317 work shifts they logged exceeded twelve hours. The risks of making an error were significantly increased when work shifts were longer than twelve hours, when nurses worked overtime, or when they worked more than forty hours per week.

  5. Migration plans and hours of work in Malaysia.

    PubMed

    Gillin, E D; Sumner, D A

    1985-01-01

    "This article describes characteristics of prospective migrants in the Malaysian Family Life Survey and investigates how planning to move affects hours of work. [The authors] use ideas about intertemporal substitution...to discuss the response to temporary and permanent wage expectations on the part of potential migrants. [An] econometric section presents reduced-form estimates for wage rates and planned migration equations and two-stage least squares estimates for hours of work. Men currently planning a move were found to work fewer hours. Those originally planning only a temporary stay at their current location work more hours." PMID:12280256

  6. Migration plans and hours of work in Malaysia.

    PubMed

    Gillin, E D; Sumner, D A

    1985-01-01

    "This article describes characteristics of prospective migrants in the Malaysian Family Life Survey and investigates how planning to move affects hours of work. [The authors] use ideas about intertemporal substitution...to discuss the response to temporary and permanent wage expectations on the part of potential migrants. [An] econometric section presents reduced-form estimates for wage rates and planned migration equations and two-stage least squares estimates for hours of work. Men currently planning a move were found to work fewer hours. Those originally planning only a temporary stay at their current location work more hours."

  7. Precarious employment, working hours, work-life conflict and health in hotel work.

    PubMed

    McNamara, Maria; Bohle, Philip; Quinlan, Michael

    2011-01-01

    Precarious or temporary work is associated with adverse outcomes including low control over working hours, work-life conflict and stress. The rise in precarious employment is most marked in the service sector but little research has been done on its health effects in this sector. This study compares permanent and temporary workers in the hotel industry, where working hours are highly variable. Survey data from 150 workers from eight 3-Star hotels in urban and regional areas around Sydney were analyzed. Forty-five per cent were male and 52 per cent were female. Fifty four per cent were permanent full-time and 46 per cent were temporary workers. The effects of employment status on perceived job security, control over working hours, and work-life conflict are investigated using PLS-Graph 3.0. The effects of control over working hours, on work-life conflict and subsequent health outcomes are also explored. Temporary workers perceived themselves as less in control of their working hours, than permanent workers (β = .27). However, they also reported lower levels of work intensity (β = .25) and working hours (β = .38). The effects of low hours control (β = .20), work intensity (β = .29), and excessive hours (β = .39) on work-life conflict (r² = .50), and subsequent health effects (r² = .30), are illustrated in the final structural equation model. PMID:20643398

  8. Relations of Work Identity, Family Identity, Situational Demands, and Sex with Employee Work Hours

    ERIC Educational Resources Information Center

    Greenhaus, Jeffrey H.; Peng, Ann C.; Allen, Tammy D.

    2012-01-01

    This study examined relations of multiple indicators of work identity and family identity with the number of weekly hours worked by 193 married business professionals. We found that men generally worked long hours regardless of the situational demands to work long hours and the strength of their work and family identities. Women's work hours, on…

  9. 5 CFR 551.521 - Fractional hours of work.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Fractional hours of work. 551.521 Section 551.521 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Overtime Pay Provisions Fractional Hours of Work §...

  10. 5 CFR 551.521 - Fractional hours of work.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Fractional hours of work. 551.521 Section 551.521 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Overtime Pay Provisions Fractional Hours of Work §...

  11. 5 CFR 551.521 - Fractional hours of work.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Fractional hours of work. 551.521 Section 551.521 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Overtime Pay Provisions Fractional Hours of Work §...

  12. Perspectives on the working hours of Australian junior doctors.

    PubMed

    Glasgow, Nicholas J; Bonning, Michael; Mitchell, Rob

    2014-01-01

    The working hours of junior doctors have been a focus of discussion in Australia since the mid-1990s. Several national organizations, including the Australian Medical Association (AMA), have been prominent in advancing this agenda and have collected data (most of which is self-reported) on the working hours of junior doctors over the last 15 years. Overall, the available data indicate that working hours have fallen in a step-wise fashion, and AMA data suggest that the proportion of doctors at high risk of fatigue may be declining. It is likely that these changes reflect significant growth in the number of medical graduates, more detailed specifications regarding working hours in industrial agreements, and a greater focus on achieving a healthy work-life balance. It is notable that reductions in junior doctors' working hours have occurred despite the absence of a national regulatory framework for working hours. Informed by a growing international literature on working hours and their relation to patient and practitioner safety, accreditation bodies such as the Australian Commission on Safety and Quality in Health Care (ACSQHC) and the Australian Medical Council (AMC) are adjusting their standards to encourage improved work and training practices. PMID:25560522

  13. 29 CFR 778.320 - Hours that would not be hours worked if not paid for.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... spent in certain types of activities which would not be regarded as working time under the Act if no compensation were provided. Preliminary and postliminary activities and time spent in eating meals between... statutory maximum. (b) Parties have agreed not to treat time as hours worked. Under the principles set...

  14. Work shift duration: a review comparing eight hour and 12 hour shift systems

    PubMed Central

    Smith, L.; Folkard, S.; Tucker, P.; Macdonald, I.

    1998-01-01

    OBJECTIVES: Shiftwork is now a major feature of working life across a broad range of industries. The features of the shift systems operated can impact on the wellbeing, performance, and sleep of shiftworkers. This paper reviews the current state of knowledge on one major characteristic of shift rotas-namely, shift duration. Evidence comparing the relative effects of eight hour and 12 hour shifts on fatigue and job performance, safety, sleep, and physical and psychological health are considered. At the organisational level, factors such as the mode of system implementation, attitudes towards shift rotas, sickness absence and turnover, overtime, and moonlighting are discussed. METHODS: Manual and electronic searches of the shiftwork research literature were conducted to obtain information on comparisons between eight hour and 12 hour shifts. RESULTS: The research findings are largely equivocal. The bulk of the evidence suggests few differences between eight and 12 hour shifts in the way they affect people. There may even be advantages to 12 hour shifts in terms of lower stress levels, better physical and psychological wellbeing, improved durations and quality of off duty sleep as well as improvements in family relations. On the negative side, the main concerns are fatigue and safety. It is noted that a 12 hour shift does not equate with being active for only 12 hours. CONCLUSIONS: There can be considerable extension of the person's time awake either side of the shift. However, the effects of longer term exposure to extended work days have been relatively uncharted in any systematic way. Longitudinal comparative research into the chronic impact of the compressed working week is needed.   PMID:9624275

  15. Health problems due to long working hours in Japan: working hours, workers' compensation (Karoshi), and preventive measures.

    PubMed

    Iwasaki, Kenji; Takahashi, Masaya; Nakata, Akinori

    2006-10-01

    Late in the 1970s, serious social concern over health problems due to long working hours has arisen in Japan. This report briefly summarizes the Japanese circumstances about long working hours and what the Government has achieved so far. The national statistics show that more than 6 million people worked for 60 h or more per week during years 2000 and 2004. Approximately three hundred cases of brain and heart diseases were recognized as labour accidents resulting from overwork (Karoshi) by the Ministry of Health, Labour and Welfare (MHLW) between 2002 and 2005. Consequently, the MHLW has been working to establish a more appropriate compensation system for Karoshi, as well as preventive measures for overwork related health problems. In 2001, the MHLW set the standards for clearly recognizing Karoshi in association with the amount of overtime working hours. These standards were based on the results of a literature review and medical examinations indicating a relationship between overwork and brain and heart diseases. In 2002, the MHLW launched the program for the prevention of health impairment due to overwork, and in 2005 the health guidance through an interview by a doctor for overworked workers has been enacted as law. Long working hours are controversial issues because of conflicts between health, safety, work-life balance, and productivity. It is obvious that we need to continue research regarding the impact on worker health and the management of long working hours.

  16. Staggered baryons

    NASA Astrophysics Data System (ADS)

    Bailey, Jon Andrew

    The strong force binds protons and neutrons within nuclei and quarks within mesons and baryons. Calculations of the masses of the light-quark baryons from the theory of the strong force, quantum chromodynamics (QCD), require numerical methods in which continuous Minkowski spacetime is replaced by a discrete Euclidean spacetime lattice. Finite computational resources and theoretical constraints impose significant limitations on lattice calculations. The price of perhaps the fastest formulation of lattice QCD, rooted staggered QCD, includes quark degrees of freedom called tastes, associated discretization effects called taste violations, and the rooting conjecture for eliminating the tastes in the continuum limit. Empirically successful rooted staggered QCD calculations of the baryon spectrum would constitute numerical evidence for the rooting conjecture and further vindication of QCD as the theory of the strong force. With such calculations as the goal, I discuss expected features of the staggered baryon spectrum, examine the spectra of interpolating operators transforming irreducibly under the staggered lattice symmetry group, construct such a set of baryon operators, and show how they could allow for particularly clean calculations of the masses of the nucleon, Delta, Sigma*, Ξ*, and O-. To quantify taste violations in baryonic quantities, I develop staggered chiral perturbation theory for light-quark baryons by mapping the Symanzik action into heavy baryon chiral perturbation theory, calculate the masses of flavor-symmetric nucleons to third order in partially quenched and fully dynamical staggered chiral perturbation theory, and discuss in detail the pattern of taste symmetry breaking and the resulting baryon degeneracies and mixings. The resulting chiral forms could be used with interpolating operators already in use to study the restoration of taste symmetry in the continuum limit.

  17. Work Hours, Retirement and Supportive Relations among Older Adults

    PubMed Central

    Nahum-Shani, Inbal

    2010-01-01

    While the literature widely acknowledges the importance of social support to the health, well-being and performance of older adults, little is known about the way in which occupational conditions affect older employees’ access to social support over time and whether these effects are maintained after retirement. Accordingly, in the current study we examine the degree to which work hours have longer term effects on the amount and type of support older individuals receive from intimate coworkers, family and non-work friends, and whether these effects are attenuated or intensified for those who retire. Longitudinal data were collected from a random sample of members of nine unions, 6 months prior to their retirement eligibility (T1) and approximately one year after Time 1 (T2). Our findings indicate that while retirement attenuates the positive association between Time 1 work hours and subsequent coworkers' support as well as the negative relationship between Time 1 work hours and subsequent non-work friends support, retirement fails to attenuate the negative effect of Time 1 work hours on subsequent family support. Policy implications are discussed. PMID:20485475

  18. Staggered chiral random matrix theory

    SciTech Connect

    Osborn, James C.

    2011-02-01

    We present a random matrix theory for the staggered lattice QCD Dirac operator. The staggered random matrix theory is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.

  19. Work Hours and Well Being: An Investigation of Moderator Effects

    ERIC Educational Resources Information Center

    Pereira, Maria C.; Coelho, Filipe

    2013-01-01

    The relationship between work hours and subjective well being is marked by contradictory findings, thereby implying that it is far from being completely understood. A study of moderator effects can help explain variations in results across studies and, thus, overcome inconsistencies in past research. Accordingly, the current study aims to…

  20. Resident work hour reform: not all doom and gloom.

    PubMed

    Koska, M T

    1990-01-20

    Limitations on the number of hours that residents may work are already in place in New York state and are being proposed in a number of other states. Now, hospitals in various parts of the country are voluntarily developing guidelines and experimenting with different ways to accommodate the changes in schedules and ensure coverage.

  1. In the Face of Conflict: Work-Life Conflict and Desired Work Hour Adjustments

    ERIC Educational Resources Information Center

    Reynolds, Jeremy

    2005-01-01

    This study helps integrate the work-life and work hours literatures by examining competing predictions about the relationship between work-life conflict and the desire for paid work. Using data from the 1997 National Study of the Changing Workforce (N = 2,178), I find that work-life conflict makes women want to decrease the number of hours they…

  2. Nurses working 12-hour shifts in the hospice setting.

    PubMed

    Hodgson, L A

    1995-04-01

    A system of 12-hour nursing shifts was adopted at a newly-opened independent hospice. This paper presents the results from an exploratory, descriptive study in which nursing staff reported perceived advantages, disadvantages and satisfaction with the 12-hour shift system. A small sample (n = 11) of both qualified and unqualified nurses working the 12-hour shift completed the questionnaire. A content analysis of the qualitative data produced a number of categories relating to the perceived advantages and disadvantages of the 12-hour shift system in relation to the respondents, to the hospice and to patient and family care. The need for continuing to monitor and evaluate the shift system was demonstrated, particularly in relation to patient and family satisfaction, and the quality of care. It was concluded that examining the advantages and disadvantages of the 12-hour shift system increased awareness of the needs of staff, presented a useful way of identifying and managing potential difficulties within the workplace, and highlighted areas for future research.

  3. Resident work hour restrictions impact chief resident operative experience.

    PubMed

    Christmas, A Britton; Brintzenhoff, Rita A; Sing, Ronald F; Schmelzer, Thomas M; Bolton, Sandra D; Miles, William S; Thomason, Michael H

    2009-11-01

    Since the institution of the Accreditation Council for Graduate Medical Education resident work restrictions, much discussion has arisen regarding the potential effect on surgical resident training. We undertook this study to examine the effects on resident operative experience. We retrospectively analyzed chief residents' Accreditation Council for Graduate Medical Education case logs before (PRE) and after (POST) the 80-hour work restriction. Overall, 22 resident logs were evaluated, six PRE and 16 POST. Four case categories were examined: total major cases, total trauma operative cases, total chief cases, and total teaching assistant cases. Significance was defined as P < 0.05. Comparing the PRE and POST groups demonstrated a trend toward fewer total major cases (1061 vs 964, P = 0.38) and fewer total trauma operative cases (55 vs 47, P = 0.37). Teaching assistant cases increased from 67 to 91 but also failed to reach significance (P = 0.37). However, further comparison between the PRE and POST groups yielded a statistically significant decrease in the number of total chief cases (494 vs 333, P = 0.0092). The significant decrease in the number of total chief cases demonstrates that the work hour restriction most affected the chief year operative experience. Further evaluation of resident participation in nonoperative facets may reveal additional deficiencies of surgical training under work hour restrictions.

  4. Work hours and self-reported hypertension among working people in California.

    PubMed

    Yang, Haiou; Schnall, Peter L; Jauregui, Maritza; Su, Ta-Chen; Baker, Dean

    2006-10-01

    Among the risk factors for hypertension, stress, especially work stress, has drawn increasing attention. Another potential work-related risk factor for hypertension identified in the past few years is work hours. This article presents an analysis of work hours and self-reported hypertension among the working population in the state of California. The data set used for this study comes from the Public Use File of the 2001 California Health Interview Survey. The logistic regression analysis shows a positive association between hours worked per week and likelihood of having self-reported hypertension. Compared with those working between 11 and 39 hours per week, individuals working 40 hours per week were 14% (95% CI: 1.01 to 1.28) more likely to report hypertension, those who worked between 41 and 50 hours per week were 17% (95% CI: 1.04 to 1.33) more likely to report hypertension, and those who worked >or=51 hours per week were 29% (95% CI: 1.10 to 1.52) more likely to report hypertension after controlling for various potentially confounding variables, including demographic and biological risk factors and socioeconomic status. This analysis provides evidence of a positive association between work hours and hypertension in the California working population.

  5. Atypical work hours and metabolic syndrome among police officers.

    PubMed

    Violanti, John M; Burchfiel, Cecil M; Hartley, Tara A; Mnatsakanova, Anna; Fekedulegn, Desta; Andrew, Michael E; Charles, Luenda E; Vila, Bryan J

    2009-01-01

    This study examined whether atypical work hours are associated with metabolic syndrome among a random sample of 98 police officers. Shift work and overtime data from daily payroll records and reported sleep duration were obtained. Metabolic syndrome was defined as elevated waist circumference and triglycerides, low HDL cholesterol, hypertension, and glucose intolerance. Multivariate analysis of variance and analysis of covariance models were used for analyses. Officers working midnight shifts were on average younger and had a slightly higher mean number of metabolic syndrome components. Stratification on sleep duration and overtime revealed significant associations between midnight shifts and the mean number of metabolic syndrome components among officers with less sleep (p = .013) and more overtime (p = .007). Results suggest shorter sleep duration and more overtime combined with midnight shift work may be important contributors to the metabolic syndrome. PMID:19864222

  6. 29 CFR 778.320 - Hours that would not be hours worked if not paid for.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....320 Section 778.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT... COMPENSATION Special Problems Effect of Paying for But Not Counting Certain Hours § 778.320 Hours that would... overtime premiums creditable toward overtime compensation under section 7(h) of the Act. Reduction...

  7. 29 CFR 778.320 - Hours that would not be hours worked if not paid for.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....320 Section 778.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT... COMPENSATION Special Problems Effect of Paying for But Not Counting Certain Hours § 778.320 Hours that would... overtime premiums creditable toward overtime compensation under section 7(h) of the Act. Reduction...

  8. 29 CFR 778.320 - Hours that would not be hours worked if not paid for.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....320 Section 778.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT... COMPENSATION Special Problems Effect of Paying for But Not Counting Certain Hours § 778.320 Hours that would... overtime premiums creditable toward overtime compensation under section 7(h) of the Act. Reduction...

  9. Fatigue and extended work hours among cardiovascular perfusionists: 2010 Survey.

    PubMed

    Trew, A; Searles, B; Smith, T; Darling, E M

    2011-09-01

    Due to the emergent unpredictable nature of cardiac surgery, perfusionists, potentially, are susceptible to extended work hours and acute sleep deprivation. While fatigue among other healthcare clinicians has been studied, there has been no research on this topic specifically in the perfusion community. Therefore, the purpose of this study was to: (1) collect preliminary data on the prevalence of fatigue in perfusion and (2) identify if there were concerns regarding fatigue, performance and perfusion safety. In May 2010, a link to a 50-question survey (surveymonkey.com) was posted on Perflist and Perfmail. The survey was closed in July 2010. There were 445 respondents and data were analyzed and expressed as a response percent. Participants included 27% chief perfusionists/managers, 67% staff perfusionists, and 6.0% other (perfusion education faculty, retired perfusionists, locum tenens). Regarding extended work hours, 68.9% of surveyed perfusionists have worked at the hospital for greater than 23 hours straight and 17.5% have worked continuously for over 36 hours. Actual performance of cardiopulmonary bypass (CPB) after 17, 23, and 36 hours of wakefulness was reported by 82.9%, 63% and 14.8% respondents, respectively. Regarding bathroom requirements while on CPB, 87.5% have felt extremely uncomfortable at least once, 19.9% have relieved themselves in the operating room at least once, and 22.3% have left the pump attended by a non-perfusionist to use the restroom at least once. Microsleep during CPB was reported by 49.5% of respondents. Automobile accidents attributed to an extended period of work and fatigue was reported by 6.9% and another 44.4% reported a near-miss auto accident. A fatigue-related minor error was reported by 66% and 6.7% admit to having a serious perfusion accident believed to be due to fatigue. Concerning critical phases of bypass, 51.5% believe that they perform less effectively when fatigued. Additionally, 75.9% indicate that they have been

  10. The Risk of Developing Diabetes in Association With Long Working Hours Differs by Shift Work Schedules

    PubMed Central

    Bannai, Akira; Yoshioka, Eiji; Saijo, Yasuaki; Sasaki, Sachiko; Kishi, Reiko; Tamakoshi, Akiko

    2016-01-01

    Background The impact of long working hours on diabetes is controversial; however, shift work is known to increase the risk of diabetes. This study aimed to investigate the association between long working hours and diabetes among civil servants in Japan separately by shift work schedules. Methods A prospective cohort study was conducted from April 2003 to March 2009. A total of 3195 men aged ≥35 years who underwent an annual health checkup at baseline were analyzed by shift work schedules (2371 non-shift workers and 824 shift workers). Self-reported working hours were categorized as 35–44 and ≥45 hours per week. The incidence of diabetes was confirmed by fasting plasma glucose concentration ≥126 mg/dL and/or self-reported medical diagnosis of diabetes at the annual checkup. A Cox proportional model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for developing diabetes associated with long working hours. Results The median follow-up period of non-shift and shift workers was 5.0 and 4.9 years, respectively. During this period, 138 non-shift workers and 46 shift workers developed diabetes. A decreased HR was found among non-shift workers working ≥45 hours per week (HR 0.84; 95% CI, 0.57–1.24); however, shift workers working ≥45 hours per week had a significantly increased risk of diabetes (HR 2.43; 95% CI, 1.21–5.10) compared with those working 35–44 hours per week. An analysis restricted to non-clerical workers also showed similar results. Conclusions The risk of diabetes associated with long working hours differed by shift work schedules. PMID:27001115

  11. Long working hours in Korea: results of the 2010 Working Conditions Survey.

    PubMed

    Park, Jungsun; Kwon, Oh Jun; Kim, Yangho

    2012-01-01

    Long working hours adversely affect workers' safety and health. In 2004, Korea passed legislation limiting the working week to 40 h, to improve quality-of-life and to increase business competitiveness. In the present study, we explored the characteristics of work in Korea and compared our data of the second Korean Working Conditions Survey (KWCS) with those of the first KWCS. We found that the average number of hours worked weekly has been reduced but the proportions of workers who work for more than 48 h per week has increased over the 4 yr between the two Korean surveys in all categories studied (male, female, employee, self-employed, and employer). We also found that self-employed and employers work much longer hours than do employees, who are protected by the Labor Standards Act. This was particularly true in the accommodation and food service sectors. In conclusion, Korean workers work longer than do workers of EU countries. The use of average figures masks differences in the numbers of working hours among those engaged in various types of employment, or in certain work sectors. Therefore, the Korean government should not simply monitor reductions in average weekly working hours, but should identify employees working for over 60 h weekly, and reduce their working time. PMID:22878357

  12. Folding Proteins at 500 ns/hour with Work Queue

    PubMed Central

    Abdul-Wahid, Badi’; Yu, Li; Rajan, Dinesh; Feng, Haoyun; Darve, Eric; Thain, Douglas; Izaguirre, Jesús A.

    2014-01-01

    Molecular modeling is a field that traditionally has large computational costs. Until recently, most simulation techniques relied on long trajectories, which inherently have poor scalability. A new class of methods is proposed that requires only a large number of short calculations, and for which minimal communication between computer nodes is required. We considered one of the more accurate variants called Accelerated Weighted Ensemble Dynamics (AWE) and for which distributed computing can be made efficient. We implemented AWE using the Work Queue framework for task management and applied it to an all atom protein model (Fip35 WW domain). We can run with excellent scalability by simultaneously utilizing heterogeneous resources from multiple computing platforms such as clouds (Amazon EC2, Microsoft Azure), dedicated clusters, grids, on multiple architectures (CPU/GPU, 32/64bit), and in a dynamic environment in which processes are regularly added or removed from the pool. This has allowed us to achieve an aggregate sampling rate of over 500 ns/hour. As a comparison, a single process typically achieves 0.1 ns/hour. PMID:25540799

  13. Long working hours and work-related cerebro-cardiovascular disease in Korea.

    PubMed

    Chung, Yun Kyung; Kwon, Young-jun

    2013-01-01

    The aim of the present study was to determine a good discriminatory cutoff for long working hours as a surrogate of chronic overload at work, which is associated with the approval of workers' compensation claims for work-related cerebro-cardiovascular disease (WR-CVD) in Korea. We evaluated weekly working hours for four weeks prior to the onset of disease for all manufacturing industry claimants (N=319) of WR-CVD in 2010. The discrimination of long working hours in predicting approval of worker's compensation pertaining to WR-CVD was compared across cases. The cutoff was calculated with sensitivity, specificity, and the area under the curve with 95% CI using the receiver operating curve (ROC) method. The cutoff point was thus calculated to be 60.75 h (AUC=0.89, 95% CI [0.84-0.93]), showing a sensitivity value of 65% and specificity of 94%. This is the first study to report that long working hours could be a predictor with good discrimination and high specificity of approval of WR-CVD cases. In Korea, long working hours and widespread chronic overload at work are recognized as a social problem. Our study results suggest an appropriate cutoff for working hours as an indicator of chronic overload for the purpose of approving claims of WR-CVD. Furthermore, these results could contribute to improving the consistency of evaluation.

  14. 29 CFR 778.318 - Productive and nonproductive hours of work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Productive and nonproductive hours of work. 778.318 Section... nonproductive hours of work. (a) Failure to pay for nonproductive time worked. Some agreements provide for payment only for the hours spent in productive work; the work hours spent in waiting time, time spent...

  15. Toward a Conceptual Clarification of Employee Responses to Flexible Working Hours: A Work Adjustment Approach.

    ERIC Educational Resources Information Center

    Pierce, Jon L.; Newstrom, John W.

    1980-01-01

    Elaborates on a work adjustment model to explain how flexible working hours can influence employee satisfaction, performance, absenteeism, tenure, organizational commitment, and job involvement. Discusses need fulfillment, stress reduction, and the harmonization of work with human circadian rhythms. (Author/RC)

  16. Work-based resources as moderators of the relationship between work hours and satisfaction with work-family balance.

    PubMed

    Valcour, Monique

    2007-11-01

    This study reports an investigation of the relationships of work hours, job complexity, and control over work time to satisfaction with work-family balance. Based on data from a sample of 570 telephone call center representatives, a moderated hierarchical regression analysis revealed that work hours were negatively related to satisfaction with work-family balance, consistent with the resource drain perspective. Job complexity and control over work time were positively associated with satisfaction with work-family balance. Control over work time moderated the relationship such that as work hours rose, workers with low control experienced a decline in work-family balance satisfaction, while workers with high control did not. Results encourage greater research attention to work characteristics, such as job complexity and control over work time, and skills that represent resources useful to the successful integration of work and family demands.

  17. [Flexibility of working hours and health: towards ergonomics of working time].

    PubMed

    Costa, G; Sartori, S

    2005-01-01

    The search for ways and methods able to increase the "flexibility" of working hours deal with several forms of intervention that depend on political choices and work management, according to specific interests and needs of the companies, the individual worker and the whole society. The main problem on the carpet is to evaluate whether that interferes with worker's health and well-being. According to the data of the last European Survey on Working Conditions (EURF 2000), it appears the workers engaged in working hours different from the traditional day work are nowadays the vast majority of the population; moreover, organisational forms which allow more flexibility, that is more autonomy, in working time arrangement are associate to better health and well-being.

  18. A gender approach to work ability and its relationship to professional and domestic work hours among nursing personnel.

    PubMed

    Rotenberg, Lúcia; Portela, Luciana Fernandes; Banks, Bahby; Griep, Rosane Harter; Fischer, Frida Marina; Landsbergis, Paul

    2008-09-01

    The association between working hours and work ability was examined in a cross-sectional study of male (N=156) and female (N=1092) nurses in three public hospitals. Working hours were considered in terms of their professional and domestic hours per week and their combined impact; total work load. Logistic regression analysis showed a significant association between total work load and inadequate work ability index (WAI) for females only. Females reported a higher proportion of inadequate WAI, fewer professional work hours but longer domestic work hours. There were no significant differences in total work load by gender. The combination of professional and domestic work hours in females seemed to best explain their lower work ability. The findings suggest that investigations into female well-being need to consider their total work load. Our male sample may have lacked sufficient power to detect a relationship between working hours and work ability.

  19. Workplace flexibility, work hours, and work-life conflict: finding an extra day or two.

    PubMed

    Hill, E Jeffrey; Erickson, Jenet Jacob; Holmes, Erin K; Ferris, Maria

    2010-06-01

    This study explores the influence of workplace flexibility on work-life conflict for a global sample of workers from four groups of countries. Data are from the 2007 International Business Machines Global Work and Life Issues Survey administered in 75 countries (N = 24,436). We specifically examine flexibility in where (work-at-home) and when (perceived schedule flexibility) workers engage in work-related tasks. Multivariate results indicate that work-at-home and perceived schedule flexibility are generally related to less work-life conflict. Break point analyses of sub-groups reveal that employees with workplace flexibility are able to work longer hours (often equivalent to one or two 8-hr days more per week) before reporting work-life conflict. The benefit of work-at-home is increased when combined with schedule flexibility. These findings were generally consistent across all four groups of countries, supporting the case that workplace flexibility is beneficial both to individuals (in the form of reduced work-life conflict) and to businesses (in the form of capacity for longer work hours). However, work-at-home appears less beneficial in countries with collectivist cultures.

  20. Work hours and work-family conflict: the double-edged sword of involvement in work and family.

    PubMed

    Matthews, Russell A; Swody, Cathleen A; Barnes-Farrell, Janet L

    2012-08-01

    In this study, we examine the role of work hours in a model that incorporates involvement in both work and family with experiences of work-family conflict and subjective well-being. Self-report data were collected from 383 full-time employees and analysed using structural equation modelling techniques. Results demonstrate that role salience was positively related to behavioural involvement with work and with family. In turn, behavioural family involvement was negatively related to work hours and family-to-work conflict, while behavioural work involvement was positively related to work hours. Behavioural family involvement was also positively related to life satisfaction. Finally, both family-to-work conflict and end-of-workday strain were negatively related to life satisfaction. Our results provide insight into unexpected problems that might arise when employees place overly high importance on work and work long hours. This study serves as a foundation for researchers to examine the interplay of time spent with work and family with other aspects of the work-family interface.

  1. Factors associated with work-related fatigue and recovery in hospital nurses working 12-hour shifts.

    PubMed

    Han, Kihye; Trinkoff, Alison M; Geiger-Brown, Jeanne

    2014-10-01

    Nurse fatigue threatens both nurse and patient safety; fatigue affects nurses' neurocognitive functioning and hinders their work performance. The authors assessed the association of work and non-work factors with acute and chronic fatigue and intershift recovery among hospital nurses working 12-hour shifts. This study used survey data from 80 nurses who provided full-time direct patient care on medical-surgical and critical care units in a large teaching hospital. Psychological job demands (e.g., work load and social support from supervisor or coworker) were significantly associated with acute and chronic fatigue and intershift recovery. Rotating shifts were significantly related to acute fatigue. Findings suggest the need for a comprehensive approach to fatigue management, including organizational support to provide healthful work schedules and favorable nursing work environments, fewer psychological and physical demands, and assistance to improve nurses' sleep quality and quantity. [Workplace Health Saf 2014;62(10):409-414.].

  2. Flexible Work Hours and Other Job Factors in Parental Time with Children

    ERIC Educational Resources Information Center

    Baxter, Jennifer

    2011-01-01

    Flexible working hours are typically seen to be advantageous to working parents, as the flexible hours more easily allow responsibilities of care and employment be balanced. But do flexible work hours actually mean that parents can spend more time with their children? This article explores this for parents of young children in Australia. The…

  3. Time for Children, One's Spouse and Oneself among Parents Who Work Nonstandard Hours

    ERIC Educational Resources Information Center

    Wight, Vanessa R.; Raley, Sara B.; Bianchi, Suzanne M.

    2008-01-01

    Using data from the 2003 and 2004 American Time Use Surveys, this article examines nonstandard work hours and their relationship to parents' family, leisure and personal care time--informing the discussion of the costs and benefits of working nonstandard hours. The results suggest that parents who work nonstandard evening hours spend less time in…

  4. Long Working Hours and Emotional Well-Being in Korean Manufacturing Industry Employees

    PubMed Central

    2013-01-01

    Objectives Korea is well known for its long work hours amongst employees. Because workers of the manufacturing industry are constantly exposed to extended work hours, this study was based on how long work hours affect their emotional well-being. Methods The analysis was done using the secondary Korean Working Condition Survey (KWCS). Long work hours were defined to be more than 48 hours, and they were subcategorized into units of 52 hours and 60 hours. Based on the WHO (five) well-being index, emotional state was subdivided into three groups - reference group, low-mood group, and possible depression group- where 28 points and 50 points were division points, and two groups were compared at a time. Association between long work hours and emotional state was analyzed using binary and multinomial logistic regression analysis. Results Working for extended working hours in the manufacturing industry showed a statistically significant increase (t test p < 0.001) in trend among the possible depression group when compared to the reference group and the low-mood group. When demographical characteristics, health behaviors, socioeconomic state, and work-related characteristics were fixed as controlled variables, as work hours increased the odds ratio of the possible depression group increased compared to the reference group, and especially the odds ratio was 2.73 times increased for work hours between 48–52 and 4.09 times increased for 60 hours or more and both were statistically significant. In comparing the low-mood group and possible depression group, as work hours increased the odds ratio increased to 1.73, 2.39, and 4.16 times, and all work hours from working 48–52 hours, 53–60 hours, and 60 hours or more were statistically significant. Multinomial logistic regression analysis also showed that among the reference group and possible group, the possible depression group was statistically significant as odds ratio increased to 2.94 times in working 53–60 hours

  5. STAGGERS IN SHEEP IN PATAGONIA

    PubMed Central

    Jones, F. S.; Arnold, J. F.

    1917-01-01

    After observations and experimental work both in the field and laboratory, the following conclusions seem justified. 1. Staggers is a non-infectious disorder affecting horses, cattle, and sheep. 2. The disease is characterized by weakness, muscular twitching, irregular movements of the head, stiffness of the limbs, and transient motor paralysis, accompanied with spastic spasms on excitement. There is also a derangement of vision and conjunctivitis. 3. The postmortem lesions are not characteristic. 4. We readily produced the disease by feeding susceptible sheep on a coarse tuft grass commonly known as coiron or pampa grass (Poa argentina). 5. The time required to produce definite symptoms by feeding the grass varied. Two animals developed typical staggers after two feedings; in another instance a period of 21 days of feeding was required. The average time for the production of unmistakable symptoms in our experiments was 10 days. 6. Many sheep recover from staggers spontaneously. A complete change of diet will usually effect a cure within 2 weeks. 7. Older .animals that have pastured for long periods on lands where the grass grows become tolerant and are rarely affected with staggers. 8. The grass is toxic to sheep at all seasons of the year. We fed late winter and early spring grass and grass in flower, and produced staggers in every instance. The young green grass is as toxic as any edible portion of the plant. PMID:19868185

  6. Work hours, sleep patterns and fatigue among merchant marine personnel.

    PubMed

    Sanquist, T F; Raby, M; Forsythe, A; Carvalhais, A B

    1997-12-01

    A field study of work and sleep patterns among commercial merchant marine personnel is reported. Data collected over a 10-30-d period from 141 subjects aboard eight ships included information concerning work-rest schedules, sleep timing, alertness on the job and critical fatigue. The data indicate that watchstanders on the 4-on, 8-off schedule show considerable disruption in their sleep. The average sleep duration for all mariners is 6.6 h; watchstanders obtain their sleep in fragmented periods that are frequently less than 5 h in duration. Analysis of critical fatigue shows an incidence of 1-24% across personnel and measures. Of particular concern are the watchstanders on the 04.00-08.00 schedule, who sleep less than 4 h per 24-h period 22% of the time. Potential countermeasures, including changes in scheduling and staffing are proposed. PMID:9493524

  7. 29 CFR 778.318 - Productive and nonproductive hours of work.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Special Problems Effect of Failure to Count Or Pay for Certain Working Hours § 778.318 Productive and... agreement setting a different rate for nonproductive hours, the employee would be owed compensation at the.... Effect of Paying for But Not Counting Certain Hours...

  8. Effects of new ways of working on work hours and work location, health and job-related outcomes.

    PubMed

    Nijp, Hylco H; Beckers, Debby G J; van de Voorde, Karina; Geurts, Sabine A E; Kompier, Michiel A J

    2016-01-01

    New ways of working (NWW) is a type of work organization that is characterized by temporal and spatial flexibility, often combined with extensive use of information and communication technologies (ICT) and performance-based management. In a three-wave intervention study, we examined the effects of NWW on both the organization of work (changes in control over time and place of work; working hours and work location; and other key job characteristics), and on employees' outcomes (work-nonwork balance; health and well-being; and job-related outcomes). We applied a quasi-experimental design within a large Dutch financial company (N = 2,912). We studied an intervention group (n = 2,391) and made comparisons with a reference group (n = 521). There were three study waves: (i) one/two months before, and (ii) 4 months and (iii) 10 months after implementation of NWW. Repeated measures analyses of covariance (involving 361 participants from the intervention group and 80 participants from the reference group) showed a large and significant shift from hours worked at the office to hours worked at home after implementation of NWW. Accordingly, commuting time was reduced. Employees remained working on week days and during day time. Psychosocial work-characteristics, work-nonwork balance, stress, fatigue, and job-related outcomes remained favourable and largely unaffected, but the health score in the intervention group decreased (medium effect). These findings suggest that the implementation of NWW does not necessarily lead to changes in psychosocial work characteristics, well-being or job-related outcomes. PMID:27223247

  9. Staggered eigenvalue mimicry

    SciTech Connect

    Duerr, Stephan; Hoelbling, Christian; Wenger, Urs

    2004-11-01

    We study the infrared part of the spectrum for UV-filtered staggered Dirac operators and compare them to the overlap counterpart. With sufficient filtering and at small enough lattice spacing the staggered spectra manage to 'mimic' the overlap version. They show a 4-fold near degeneracy, and a clear separation between would-be zero modes and nonzero modes. This suggests an approximate index theorem for filtered staggered fermions and a correct sensitivity to the topology of QCD. Moreover, it supports square-rooting the staggered determinant to obtain dynamical ensembles with N{sub f}=2.

  10. Possible Aoki phase for staggered fermions

    SciTech Connect

    Aubin, C.; Wang Qinghai

    2004-12-01

    The phase diagram for staggered fermions is discussed in the context of the staggered chiral Lagrangian, extending previous work on the subject. When the discretization errors are significant, there may be an Aoki-like phase for staggered fermions, where the remnant SO(4) taste-symmetry is broken down to SO(3). We solve explicitly for the mass spectrum in the 3-flavor degenerate mass case and discuss qualitatively the 2+1-flavor case. From numerical results we find that current simulations are outside the staggered-Aoki phase. As for near-future simulations with more-improved versions of the staggered action, it seems unlikely that these will be in the Aoki phase for any realistic value of the quark mass, although the evidence is not conclusive.

  11. The Association between Long Working Hours and Self-Rated Health

    PubMed Central

    2014-01-01

    Objectives This study was conducted to determine the number of hours worked per week by full-time wage workers by using the data of the Korean Labor and Income Panel Study (KLIPS), which represents the domestic urban area household, and to determine the association between weekly working hours and the level of self-rated health. Methods We used data from the 11th KLIPS conducted in 2008. The subjects of this study were 3,699 full-time wage workers between the ages of 25 and 64 years. The association between weekly working hours and self-rated health was analyzed considering socio-demographic characteristics, work environment, and health-related behaviors. Results Among the workers, 29.7% worked less than 40 hours per week; 39.7%, more than 40 to 52 hours; 19.7%, more than 52 to 60 hours; and 10.9%, more than 60 hours per week. After controlling for socio-demographic variables, work environment-related variables, and health-related behavior variables, the odds ratio (OR) for poor self-rated health for the group working more than 40 hours and up to 52 hours was calculated to be 1.06 (95% confidence interval (CI), 0.89-1.27) when the group working less than 40 hours per week was considered the reference. The OR for the group working more than 60 hours was 1.42 (95% CI, 1.10-1.83) and that for the group working more than 52 hours and up to 60 hours was 1.07 (95% CI, 0.86-1.33). After stratification by gender and tenure, the OR of the female workers group and that of the group with a tenure of more than 1 year were found to be significantly higher than those of the other groups. Conclusions This study showed that workers working more than 60 hours per week have a significantly higher risk of poor self-rated health than workers working less than 40 hours per week. This effect was more obvious for the female workers group and the group with a tenure of more than 1 year. In the future, longitudinal studies may be needed to determine the association between long working

  12. Don't Blame the Babies: Work Hour Mismatches and the Role of Children

    ERIC Educational Resources Information Center

    Reynolds, Jeremy; Johnson, David R.

    2012-01-01

    Many authors suggest that having children leads to gaps between the number of hours people prefer to work and the hours they actually work. Existing research, however, offers mixed support for that claim. We discuss the roots of this popular but poorly supported hypothesis and offer the first review of research on the topic, paying special…

  13. Work Hours Regulations for House Staff in Psychiatry: Bad or Good for Residency Training?

    ERIC Educational Resources Information Center

    Rasminsky, Sonya; Lomonaco, Allison; Auchincloss, Elizabeth

    2008-01-01

    Objective: The movement to limit work hours for house staff has gained momentum in recent years. The authors set out to review the literature on work hours reform, particularly as it applies to psychiatric residency training, and to provide two different viewpoints on the controversy. Methods: The authors present the historical background of work…

  14. New Measures of Teachers' Work Hours and Implications for Wage Comparisons

    ERIC Educational Resources Information Center

    West, Kristine L.

    2014-01-01

    Researchers have good data on teachers' annual salaries but a hazy understanding of teachers' hours of work. This makes it difficult to calculate an accurate hourly wage and leads policy makers to default to anecdote rather than fact when debating teacher pay. Using data from the American Time Use Survey, I find that teachers work an average of…

  15. Chicago Mothers on Finding and Using Child Care during Nonstandard Work Hours

    ERIC Educational Resources Information Center

    Stoll, Marcia; Alexander, David; Nicpon, Christine

    2015-01-01

    Few issues confound child care policy more than the fact that very large numbers of mothers work evenings, overnight, or weekend hours when fewer child care programs operate. The authors interviewed 50 single Chicago mothers with nontraditional work hours about their experiences finding and using child care. Participants' responses addressed…

  16. 48 CFR 52.222-4 - Contract Work Hours and Safety Standards Act-Overtime Compensation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... duplicate those required for construction work by Department of Labor regulations at 29 CFR 5.5(a)(3... CLAUSES Text of Provisions and Clauses 52.222-4 Contract Work Hours and Safety Standards Act—Overtime... excess of the standard workweek of 40 hours without paying overtime wages required by the Contract...

  17. Impact of Long Farm Working Hours on Child Safety Practices in Agricultural Settings

    ERIC Educational Resources Information Center

    Marlenga, Barbara; Pahwa, Punam; Hagel, Louise; Dosman, James; Pickett, William

    2010-01-01

    Objectives: To characterize working hours of adult farm owner-operators and their spouses by season, and to examine associations between working hours and farm safety practices affecting children. Methods: We conducted a secondary analysis of cross-sectional survey data collected as part of an existing study of injury and its determinants.…

  18. Safe working hours--doctors in training a best practice issue.

    PubMed

    Lewis, Andrew

    2002-01-01

    In 1995, the Australian Medical Association launched its Safe Working Hours campaign. By 1998, this had been developed into a National Code of Conduct that continues to resonate in the Australian public health system. However, and particularly in respect of Doctors in Training (DITs) who continue to work long hours, there are levels of resistance to proposals that seek to re-organise work or change prevailing professional and cultural expectations. Long working hours have substantial impacts on a DIT's capacity to consistently deliver high quality patient care, dilute the effectiveness of their training regime and have negative consequences on their health, social life and family responsibilities. While public hospitals often maintain the view that minimal budget flexibility restricts their capacity to affect change in a positive way, in fact devisable productivity and efficiency gains can be achieved by reducing working hours. Further, the medical profession needs to consider whether long hours provide an optimal environment for quality learning and performance. PMID:12536869

  19. Balancing Work and Academics in College: Why Do Students Working 10 to 19 Hours Per Week Excel?

    ERIC Educational Resources Information Center

    Dundes, Lauren; Marx, Jeff

    2007-01-01

    Given that 74% of undergraduates work an average of 25.5 hours per week while going to school, we know surprisingly little about how off-campus employment affects undergraduates and to what extent its impact varies by the number of hours worked. Our survey of undergraduates at a small liberal arts college found that the academic performance of…

  20. The quantity of nursing care on wards working 8- and 12-hour shifts.

    PubMed

    Reid, N; Robinson, G; Todd, C

    1993-10-01

    Interest in 12-hour nursing shifts has been renewed in response to demands for improved cost-effectiveness in the NHS, but the effects of this shift on the delivery of patient care have been unclear. This paper describes the results of a repeated-measures study of 10 wards, using activity analysis to describe patterns of care under an 8-hour compared to a 12-hour shift system. Significant reductions in the amount of direct patient care were found under the 12-hour shift, with corresponding increases in unofficial work-breaks. It is suggested that these findings, which were consistent over all study wards and throughout the whole 12-hour day, demonstrate a "pacing" effect by nurses who face 12 hours on duty. Such a detrimental effect should be a major consideration when coming to any decision to implement a 12-hour shift.

  1. What's parenthood got to do with it?: men's hours of paid work.

    PubMed

    Dermott, Esther

    2006-12-01

    It is commonly reported that fathers in Britain work longer hours than non-fathers. This statistic is frequently used as supporting evidence for the argument that the role of fathers within families remains primarily concerned with financial provisioning. In this paper it is shown, through regression models, that once other factors are taken into account the significance of fatherhood in relation to hours of paid work disappears. This highlights fatherhood as a period in the life course which often coincides with longer working hours but challenges the assumption of a causal relationship. PMID:17168941

  2. Workers With Irregular Hours During Seasonal Work Surges: Promoting Healthy Sleep.

    PubMed

    Butterfield, Patricia

    2016-03-01

    A significant proportion of the labor force works irregular hours during harvest, summer, or holiday work surges. Unfortunately such workers are often uninformed about the importance of sleep and fatigue management. Seasonally timed worker training can improve health and safety outcomes during work surges. PMID:26941083

  3. Relationship of Work Hours with Selected Health Behaviors and Academic Progress among a College Student Cohort

    ERIC Educational Resources Information Center

    Miller, Kim; Danner, Fred; Staten, Ruth

    2008-01-01

    Approximately 57% of college students work while attending school. Health risks related to working while in college have not been widely studied. Objective: The authors' purpose in this study was to determine associations between hours worked, binge drinking, sleep habits, and academic performance among a college student cohort. Participants and…

  4. Workers With Irregular Hours During Seasonal Work Surges: Promoting Healthy Sleep.

    PubMed

    Butterfield, Patricia

    2016-03-01

    A significant proportion of the labor force works irregular hours during harvest, summer, or holiday work surges. Unfortunately such workers are often uninformed about the importance of sleep and fatigue management. Seasonally timed worker training can improve health and safety outcomes during work surges.

  5. The Not-so-Staggering Effect of Staggered Animated Transitions on Visual Tracking.

    PubMed

    Chevalier, Fanny; Dragicevic, Pierre; Franconeri, Steven

    2014-12-01

    Interactive visual applications often rely on animation to transition from one display state to another. There are multiple animation techniques to choose from, and it is not always clear which should produce the best visual correspondences between display elements. One major factor is whether the animation relies on staggering-an incremental delay in start times across the moving elements. It has been suggested that staggering may reduce occlusion, while also reducing display complexity and producing less overwhelming animations, though no empirical evidence has demonstrated these advantages. Work in perceptual psychology does show that reducing occlusion, and reducing inter-object proximity (crowding) more generally, improves performance in multiple object tracking. We ran simulations confirming that staggering can in some cases reduce crowding in animated transitions involving dot clouds (as found in, e.g., animated 2D scatterplots). We empirically evaluated the effect of two staggering techniques on tracking tasks, focusing on cases that should most favour staggering. We found that introducing staggering has a negligible, or even negative, impact on multiple object tracking performance. The potential benefits of staggering may be outweighed by strong costs: a loss of common-motion grouping information about which objects travel in similar paths, and less predictability about when any specific object would begin to move. Staggering may be beneficial in some conditions, but they have yet to be demonstrated. The present results are a significant step toward a better understanding of animation pacing, and provide direction for further research.

  6. The impact of reduced working hours on surgical training in Australia and New Zealand.

    PubMed

    Gough, Ian R

    2011-01-01

    There is a worldwide trend for reduced working hours for doctors, particularly in the developed western countries. This has been led by the introduction of the European Working Time Directive (EWTD) that has had a significant impact on work patterns and training. Australia currently has a more flexible working environment but this is changing. In New Zealand there is a contract for resident doctors defining a maximum 72 h of rostered work per week. PMID:21550001

  7. "Where work is play for mortal stakes": the good hour in child analysis.

    PubMed

    Ablon, S L

    2000-01-01

    To explore the concept of the "good hour" in child analysis I discuss an hour in the analysis of a six-and-a-half-year-old girl. Elements of this hour include a palpable therapeutic alliance, affective immediacy, surprise, and discovery, oscillating therapeutic action of action, play, and verbalization, creative accessibility to the unconscious, the transference, the countertransference, and a capacity to work with conflict, defense, and fantasy. These qualities are similar to those described by Kris for adult analysis over forty years ago. The present hour, however, illustrates greater emphasis on affect rather than drive, the therapeutic action of play in the analytic setting, and the transformative importance of the relationship. In addition, the hour highlights a greater focus on communication by action and enactment, the highly informative uses of the countertransference, and the co-creation of the analytic process.

  8. Surveying the Impact of Work Hours and Schedules on Commercial Motor Vehicle Driver Sleep

    PubMed Central

    Hege, Adam; Perko, Michael; Johnson, Amber; Yu, Chong Ho; Sönmez, Sevil; Apostolopoulos, Yorghos

    2015-01-01

    Background Given the long hours on the road involving multiple and interacting work stressors (i.e., delivery pressures, irregular shifts, ergonomic hazards), commercial drivers face a plethora of health and safety risks. Researchers goal was to determine whether and to what extent long-haul trucker work schedules influence sleep duration and quality. Methods Survey and biometric data collected from male long-haul truck drivers at a major truckstop in central North Carolina over a six month period. Results Daily hours worked (mean = 11 hours, 55 minutes) and frequency of working over government-mandated daily HOS regulations (23.8% “frequently or always”) were statistically significant predictors of sleep duration. Miles driven per week (mean = 2,812.61), irregular daily hours worked (63.8%), and frequency of working over the daily hour limit (23.8% “frequently or always”) were statistically significant predictors of sleep quality. Conclusion Implications of findings suggest a comprehensive review of the regulations and operational conditions for commercial motor vehicle drivers be undertaken. PMID:26106509

  9. Exposing physicians to reduced residency work hours did not adversely affect patient outcomes after residency.

    PubMed

    Jena, Anupam B; Schoemaker, Lena; Bhattacharya, Jay

    2014-10-01

    In 2003, work hours for physicians-in-training (residents) were capped by regulation at eighty hours per week, leading to the hotly debated but unexplored issue of whether physicians today are less well trained as a result of these work-hour reforms. Using a unique database of nearly all hospitalizations in Florida during 2000-09 that were linked to detailed information on the medical training history of the physician of record for each hospitalization, we studied whether hospital mortality and patients' length-of-stay varied according to the number of years a physician was exposed to the 2003 duty-hour regulations during his or her residency. We examined this database of practicing Florida physicians, using a difference-in-differences analysis that compared trends in outcomes of junior physicians (those with one-year post-residency experience) pre- and post-2003 to a control group of senior physicians (those with ten or more years of post-residency experience) who were not exposed to these reforms during their residency. We found that the duty-hour reforms did not adversely affect hospital mortality and length-of-stay of patients cared for by new attending physicians who were partly or fully exposed to reduced duty hours during their own residency. However, assessment of the impact of the duty-hour reforms on other clinical outcomes is needed.

  10. Parental Involvement, Child Temperament, and Parents’ Work Hours: Differential Relations for Mothers and Fathers

    PubMed Central

    Brown, Geoffrey L.; McBride, Brent A.; Bost, Kelly K.; Shin, Nana

    2014-01-01

    This study examined how child temperament was related to parents’ time spent accessible to and interacting with their 2-year-olds. Bivariate analyses indicated that both fathers and mothers spent more time with temperamentally challenging children than easier children on workdays, but fathers spent less time with challenging children than easier children on non-workdays. After accounting for work hours, some associations between temperament and fathers’ workday involvement dropped to non-significance. For fathers, work hours also moderated the relation between irregular temperament and workday play. For mothers, work hours moderated the relation between both difficult and irregular temperament and workday interaction. Mothers also spent more time with girls (but not boys) who were temperamentally irregular. Results speak to the influence of child temperament on parenting behavior, and the differential construction of parenting roles as a function of child characteristics and patterns of work. PMID:25960588

  11. Musculoskeletal pain and insomnia among workers with different occupations and working hours.

    PubMed

    Moreno, Claudia R C; Lowden, Arne; Vasconcelos, Suleima; Marqueze, Elaine C

    2016-01-01

    Several studies have shown a bidirectional relationship between insomnia and pain. The aim of this study was to evaluate whether working hours and type of occupation are associated with insomnia, pain and insomnia plus pain. Insomnia and musculoskeletal pain symptoms were measured in airline pilots, rural workers and factory workers using validated indexes. Rural and night work were predictors for the outcomes (insomnia and pain). However, musculoskeletal pain was found to be a predictor of insomnia but not vice versa. The current findings suggest that working hours and type of occupation play a role in the sleep-pain relationship. PMID:27088881

  12. Time spent sitting during and outside working hours in bus drivers: A pilot study.

    PubMed

    Varela-Mato, Veronica; Yates, Thomas; Stensel, David J; Biddle, Stuart J H; Clemes, Stacy A

    2016-06-01

    This cross-sectional pilot study objectively measured sedentary and non-sedentary time in a sample of bus drivers from the East Midlands, United Kingdom. Participants wore an activPAL3 inclinometer for 7 days and completed a daily diary. Driver's blood pressure, heart rate, waist circumference and body composition were measured objectively at the outset. The proportions of time spent sedentary and non-sedentary were calculated during waking hours on workdays and non-workdays and during working-hours and non-working-hours on workdays. 28 (85% of those enrolled into the study) provided valid objective monitoring data (89.3% male, [median ± IQR] age: 45.2 ± 12.8 years, BMI 28.1 ± 5.8 kg/m(2)). A greater proportion of time was spent sitting on workdays than non-workdays (75% [724 ± 112 min/day] vs. 62% [528 ± 151 min/day]; p < 0.001), and during working-hours than non-working-hours (83% [417 ± 88 min/day] vs. 68% [307 ± 64 min/day]; p < 0.001) on workdays. Drivers spent less than 3% of their overall time stepping. Bus drivers accumulate high levels of sitting time during working-hours and outside working-hours. Interventions are urgently needed in this at-risk group, which should focus on reducing sitting and increasing movement during breaks and increasing physical activity during leisure time to improve cardiovascular health.

  13. Time spent sitting during and outside working hours in bus drivers: A pilot study

    PubMed Central

    Varela-Mato, Veronica; Yates, Thomas; Stensel, David J.; Biddle, Stuart J.H.; Clemes, Stacy A.

    2015-01-01

    This cross-sectional pilot study objectively measured sedentary and non-sedentary time in a sample of bus drivers from the East Midlands, United Kingdom. Participants wore an activPAL3 inclinometer for 7 days and completed a daily diary. Driver's blood pressure, heart rate, waist circumference and body composition were measured objectively at the outset. The proportions of time spent sedentary and non-sedentary were calculated during waking hours on workdays and non-workdays and during working-hours and non-working-hours on workdays. 28 (85% of those enrolled into the study) provided valid objective monitoring data (89.3% male, [median ± IQR] age: 45.2 ± 12.8 years, BMI 28.1 ± 5.8 kg/m2). A greater proportion of time was spent sitting on workdays than non-workdays (75% [724 ± 112 min/day] vs. 62% [528 ± 151 min/day]; p < 0.001), and during working-hours than non-working-hours (83% [417 ± 88 min/day] vs. 68% [307 ± 64 min/day]; p < 0.001) on workdays. Drivers spent less than 3% of their overall time stepping. Bus drivers accumulate high levels of sitting time during working-hours and outside working-hours. Interventions are urgently needed in this at-risk group, which should focus on reducing sitting and increasing movement during breaks and increasing physical activity during leisure time to improve cardiovascular health. PMID:26844184

  14. Taking Pressure off Families: Child-Care Subsidies Lessen Mothers' Work-Hour Problems

    ERIC Educational Resources Information Center

    Press, Julie E.; Fagan, Jay; Laughlin, Lynda

    2006-01-01

    We use the Philadelphia Survey of Child Care and Work to model the effect of child-care subsidies and other ecological demands and resources on the work hour, shift, and overtime problems of 191 low-income urban mothers. Comparing subsidy applicants who do and do not receive cash payments for child care, we find that mothers who receive subsidies…

  15. Comparison of Burnout among Medical Residents before and after the Implementation of Work Hours Limits

    ERIC Educational Resources Information Center

    Martini, Shahm; Arfken, Cynthia L.; Balon, Richard

    2006-01-01

    Objective: The authors assess whether implementation of work hour limits is associated with a lower prevalence of medical resident burnout. Method: A survey was mailed to medical residents in different medical specialties at one university. Results: Somewhat lower burnout prevalence was reported among residents after implementation of work hour…

  16. Long Work Hours and Family Life: A Cross-National Study of Employees' Concerns

    ERIC Educational Resources Information Center

    Wharton, Amy S.; Blair-Loy, Mary

    2006-01-01

    Work-family conflict is a pressing research and policy issue. The authors extend previous scholarship on this issue by studying elite employees worries about the effects of long work hours on those in their personal life. This issue is researched cross-nationally in a sample of managers and professionals based in the United States, London, and…

  17. Employees' use of social media for private reasons during working hours

    NASA Astrophysics Data System (ADS)

    Gunnlaugsdottir, Johanna

    2015-02-01

    The objectives of the study were to find out: Whether Icelandic organizations allowed open access to social media (SM), whether the respondents used SM for private reasons during working hours, which SM they used, how much time they devoted to such use, and what was the attitude of managers and the employees themselves towards such use. The respondents were asked to disclose whether they worked in the private or the public sector and the type of organization that they worked for. This was a two-dimensional study: A questionnaire sent to an internet panel and a telephone survey both based on a random sample selected from the National Registry in February 2013. A similar study has not been performed in Iceland before. Foreign studies of the same nature are not known, only related research. The main findings were that about half of the organizations allowed open access to SM, just below 50% of respondents took advantage of SM for personal use during working hours and the great majority used Facebook. Employees used a considerable part of their working hours for personal use of SM. The majority of respondents were of the opinion that managers objected to the use of SM during working hours and a larger majority believed that such use of themselves was unacceptable. The survey adds valuable information for a better understanding of the status of SM at places of work. The results could be of value to organizations that want to evaluate the pros and cons of SM for the organization.

  18. Health and safety problems associated with long working hours: a review of the current position.

    PubMed Central

    Spurgeon, A; Harrington, J M; Cooper, C L

    1997-01-01

    The European Community Directive on Working Time, which should have been implemented in member states of the European Community by November 1996, contains several requirements related to working hours, including the right of employees to refuse to work more than 48 hours a week. The United Kingdom government attempted to oppose the Directive, arguing that there is no convincing evidence that hours of work should be limited on health and safety grounds. Much of the research in this area has focused on the problems of shiftworking and previous reviews have therefore tended to emphasise this aspect of working hours. However, there is much less information about the effects of overtime work, which is a central element of the terms of the Directive. This paper reviews the current evidence relating to the potential effects on health and performance of extensions to the normal working day. Several gaps in the literature are identified. Research to date has been restricted to a limited range of health outcomes--namely, mental health and cardiovascular disorders. Other potential effects which are normally associated with stress--for example, gastrointestinal disorders, musculoskeletal disorders, and problems associated with depression of the immune system, have received little attention. Also, there have been few systematic investigations of performance effects, and little consideration of the implications for occupational exposure limits of extensions to the working day. Existing data relate largely to situations where working hours exceed 50 a week and there is a lack of information on hours below this level, which is of direct relevance to the European Community proposal. Finally, it is clear from investigations relating to shiftwork that a range of modifying factors are likely to influence the level and nature of health and performance outcomes. These include the attitudes and motivation of the people concerned, the job requirements, and other aspects of the

  19. Flexible working hours, health, and well-being in Europe: some considerations from a SALTSA project.

    PubMed

    Costa, Giovanni; Akerstedt, Torbjorn; Nachreiner, Friedhelm; Baltieri, Federica; Carvalhais, José; Folkard, Simon; Dresen, Monique Frings; Gadbois, Charles; Gartner, Johannes; Sukalo, Hiltraud Grzech; Härmä, Mikko; Kandolin, Irja; Sartori, Samantha; Silvério, Jorge

    2004-01-01

    The project brought together researchers from 9 EU-Countries and resulted in a number of actions, in particular the following: (a) There is an urgent need of defining the concept of flexible working hours, since it has been used in many different and even counterintuitive ways; the most obvious distinction is where the influence over the working hours lies, that is between the "company-based flexibility" and the "individual-oriented flexibility"; (b) The review of the Legislation in force in the 15 European countries shows that the regulation of working times is quite extensive and covers (Council Directive 93/104/EC) almost all the various arrangements of working hours (i.e., part-time, overtime, shift, and night work), but fails to provide for flexibility; (c) According to the data of the Third EU Survey on Working Conditions, longer and "irregular" working hours are in general linked to lower levels of health and well-being; moreover, low (individual) flexibility and high variability of working hours (i.e., company-based flexibility) were consistently associated with poor health and well-being, while low variability combined with high autonomy showed positive effects; (d) Six substudies from different countries demonstrated that flexible working hours vary according to country, economic sector, social status, and gender; overtime is the most frequent form of company-based flexibility but has negative effects on stress, sleep, and social and mental health; individual flexibility alleviates the negative effects of the company-based flexibility on subjective health, safety, and social well-being; (e) The literature review was able to list more than 1,000 references, but it was striking that most of these documents were mainly argumentative with very little empirical data. Thus, one may conclude that there is a large-scale intervention ongoing in our society with almost completely unknown and uncontrolled effects. Consequently, there is a strong need for systematic

  20. The crossover effect of spouses’ long working hours on depressive symptoms and suicidal ideation

    PubMed Central

    YOON, Jin-Ha; KANG, Mo-Yeol

    2016-01-01

    To examine the association between spouses’ weekly working hours (SWWH) and psychological symptoms such as depressive symptom and suicidal ideation. We used data from the fourth and fifth Korean National Health and Nutrition Examination Survey (2007–2012). We collected information about general characteristics, depressive symptoms, suicidal ideation, and working hours. After inclusion and exclusion criteria were applied, a sample of 8,056 house units was used for analysis. A multiple logistic regression was conducted to investigate the association between SWWH and depressive symptoms, as well as suicidal ideation, to estimate the odds ratio (OR). The relationship between SWWH and psychological symptoms were linear in husbands, and J-shaped in wives. ORs for husbands’ depressive symptoms and suicidal ideation increased according to increase in SWWH (p-values for trend were 0.0045 and <0.001, respectively). Crude ORs for wives’ depressive symptoms and suicidal ideation decreased until SWWH of 40 to 49 hours, but increased after SWWH of 40 to 49 hours (all p-values were below 0.01). Similar trends were observed after adjustment for age, obesity, household income, and one’s own weekly working hours, up to 1.33 and 1.57 in husbands, and 1.29 and 1.32 in wives, respectively. SWWH is negatively associated with mental health. PMID:27052574

  1. US public opinion regarding proposed limits on resident physician work hours

    PubMed Central

    2010-01-01

    Background In both Europe and the US, resident physician work hour reduction has been a source of controversy within academic medicine. In 2008, the Institute of Medicine (IOM) recommended a reduction in resident physician work hours. We sought to assess the American public perspective on this issue. Methods We conducted a national survey of 1,200 representative members of the public via random digit telephone dialing in order to describe US public opinion on resident physician work hour regulation, particularly with reference to the IOM recommendations. Results Respondents estimated that resident physicians currently work 12.9-h shifts (95% CI 12.5 to 13.3 h) and 58.3-h work weeks (95% CI 57.3 to 59.3 h). They believed the maximum shift duration should be 10.9 h (95% CI 10.6 to 11.3 h) and the maximum work week should be 50 h (95% CI 49.4 to 50.8 h), with 1% approving of shifts lasting >24 h (95% CI 0.6% to 2%). A total of 81% (95% CI 79% to 84%) believed reducing resident physician work hours would be very or somewhat effective in reducing medical errors, and 68% (95% CI 65% to 71%) favored the IOM proposal that resident physicians not work more than 16 h over an alternative IOM proposal permitting 30-h shifts with ≥5 h protected sleep time. In all, 81% believed patients should be informed if a treating resident physician had been working for >24 h and 80% (95% CI 78% to 83%) would then want a different doctor. Conclusions The American public overwhelmingly favors discontinuation of the 30-h shifts without protected sleep routinely worked by US resident physicians and strongly supports implementation of restrictions on resident physician work hours that are as strict, or stricter, than those proposed by the IOM. Strong support exists to restrict resident physicians' work to 16 or fewer consecutive hours, similar to current limits in New Zealand, the UK and the rest of Europe. PMID:20515479

  2. Long Working Hours and Subsequent Use of Psychotropic Medicine: A Study Protocol

    PubMed Central

    Albertsen, Karen

    2014-01-01

    Background Mental ill health is the most frequent cause of long-term sickness absence and disability retirement in Denmark. Some instances of mental ill health might be due to long working hours. A recent large cross-sectional study of a general working population in Norway found that not only “very much overtime”, but also “moderate overtime” (41-48 work hours/week) was significantly associated with increased levels of both anxiety and depression. These findings have not been sufficiently confirmed in longitudinal studies. Objective The objective of the study is to give a detailed plan for a research project aimed at investigating the possibility of a prospective association between weekly working hours and use of psychotropic medicine in the general working population of Denmark. Methods People from the general working population of Denmark have been surveyed, at various occasions in the time period 1995-2010, and interviewed about their work environment. The present study will link interview data from these surveys to national registers covering all inhabitants of Denmark. The participants will be followed for the first occurrence of redeemed prescriptions for psychotropic medicine. Poisson regression will be used to analyze incidence rates as a function of weekly working hours (32-40; 41-48; > 48 hours/week). The analyses will be controlled for gender, age, sample, shift work, and socioeconomic status. According to our feasibility studies, the statistical power is sufficient and the exposure is stable enough to make the study worth the while. Results The publication of the present study protocol ends the design phase of the project. In the next phase, the questionnaire data will be forwarded to Statistics Denmark where they will be linked to data on deaths, migrations, socioeconomic status, and redeemed prescriptions for psychotropic medication. We expect the analysis to be completed by the end of 2014 and the results to be published mid 2015

  3. School Foodservice Employees' Perceptions of Practice: Differences by Generational Age and Hours Worked

    ERIC Educational Resources Information Center

    Strohbehn, Catherine; Jun, Jinhyun; Arendt, Susan

    2014-01-01

    Purpose/Objectives: This study investigated the influences of school foodservice employees' age and average number of hours worked per week on perceived safe food handling practices, barriers, and motivators. Methods: A bilingual survey (English and Spanish) was developed to assess reported food safety practices, barriers, and motivators to…

  4. 48 CFR 22.403-3 - Contract Work Hours and Safety Standards Act.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Contract Work Hours and Safety Standards Act. 22.403-3 Section 22.403-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS...

  5. 48 CFR 22.403-3 - Contract Work Hours and Safety Standards Act.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract Work Hours and Safety Standards Act. 22.403-3 Section 22.403-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS APPLICATION OF LABOR LAWS TO GOVERNMENT ACQUISITIONS...

  6. Mothers' and Fathers' Work Hours, Child Gender, and Behavior in Middle Childhood

    ERIC Educational Resources Information Center

    Johnson, Sarah; Li, Jianghong; Kendall, Garth; Strazdins, Lyndall; Jacoby, Peter

    2013-01-01

    This study examined the association between typical parental work hours (including nonemployed parents) and children's behavior in two-parent heterosexual families. Child behavior was measured by the Child Behavior Checklist (CBCL) at ages 5, 8, and 10 in the Western Australian Pregnancy Cohort (Raine) Study ("N" = 4,201 child-year observations).…

  7. The relationship between hours worked and partner's disability in opposite- and same-sex couples.

    PubMed

    Leppel, Karen

    2008-11-01

    When a partner is disabled and not in the labour force, the need for earnings provided by the non-disabled partner increases. However, the disabled partner's need for care raises the value of time spent at home by the non-disabled partner. The direction of the relation between partner disability and hours worked varies with couple type because connecting links are affected by couple type. Relevant issues include foregone earnings, amount of income lost by the disabled partner, accumulated savings and healthcare coverage. In order to determine whether there is a significant relation between hours worked and having a disabled partner, controlling for other characteristics, Tobit regression equations were estimated using the US 2000 Decennial Census 5% sample. Among same-sex partners, unmarried opposite-sex partners and married men, individuals with disabled partners worked fewer hours in the labour force than did those without disabled partners. Only among married women did those with a disabled partner work more hours. PMID:18975226

  8. Association among Working Hours, Occupational Stress, and Presenteeism among Wage Workers: Results from the Second Korean Working Conditions Survey

    PubMed Central

    2014-01-01

    Objectives The purpose of the present study was to identify the association between presenteeism and long working hours, shiftwork, and occupational stress using representative national survey data on Korean workers. Methods We analyzed data from the second Korean Working Conditions Survey (KWCS), which was conducted in 2010, in which a total of 6,220 wage workers were analyzed. The study population included the economically active population aged above 15 years, and living in the Republic of Korea. We used the chi-squared test and multivariate logistic regression to test the statistical association between presenteeism and working hours, shiftwork, and occupational stress. Results Approximately 19% of the workers experienced presenteeism during the previous 12 months. Women had higher rates of presenteeism than men. We found a statistically significant dose–response relationship between working hours and presenteeism. Shift workers had a slightly higher rate of presenteeism than non-shift workers, but the difference was not statistically significant. Occupational stress, such as high job demand, lack of rewards, and inadequate social support, had a significant association with presenteeism. Conclusions The present study suggests that long working hours and occupational stress are significantly related to presenteeism. PMID:24661575

  9. Reducing Risks to Women Linked to Shift Work, Long Work Hours, and Related Workplace Sleep and Fatigue Issues.

    PubMed

    Caruso, Claire C

    2015-10-01

    In the United States, an estimated 12% to 28% of working women are on shift work schedules, and 12% work more than 48 hours per week. Shift work and long work hours are associated with many health and safety risks, including obesity, injuries, and negative reproductive outcomes. Over time, the worker is at risk for developing a wide range of chronic diseases. These work schedules can also strain personal relationships, owing to fatigue and poor mood from sleep deprivation and reduced quality time to spend with family and friends. Worker errors from fatigue can lead to reduced quality of goods and services, negatively impacting the employer. In addition, mistakes by fatigued workers can have far-reaching negative effects on the community, ranging from medical care errors to motor vehicle crashes and industrial disasters that endanger others. To reduce the many risks that are linked to these demanding work hours, the National Institute for Occupational Safety and Health (NIOSH) conducts research, develops guidance and authoritative recommendations, and translates and disseminates scientific information to protect workers, their families, employers, and the community. The key message to reduce these risks is making sleep a priority in the employer's systems for organizing work and in the worker's personal life. The NIOSH website has freely available online training programs with suggestions for workers and their managers to help them better cope with this workplace hazard. PMID:26334800

  10. Reducing Risks to Women Linked to Shift Work, Long Work Hours, and Related Workplace Sleep and Fatigue Issues.

    PubMed

    Caruso, Claire C

    2015-10-01

    In the United States, an estimated 12% to 28% of working women are on shift work schedules, and 12% work more than 48 hours per week. Shift work and long work hours are associated with many health and safety risks, including obesity, injuries, and negative reproductive outcomes. Over time, the worker is at risk for developing a wide range of chronic diseases. These work schedules can also strain personal relationships, owing to fatigue and poor mood from sleep deprivation and reduced quality time to spend with family and friends. Worker errors from fatigue can lead to reduced quality of goods and services, negatively impacting the employer. In addition, mistakes by fatigued workers can have far-reaching negative effects on the community, ranging from medical care errors to motor vehicle crashes and industrial disasters that endanger others. To reduce the many risks that are linked to these demanding work hours, the National Institute for Occupational Safety and Health (NIOSH) conducts research, develops guidance and authoritative recommendations, and translates and disseminates scientific information to protect workers, their families, employers, and the community. The key message to reduce these risks is making sleep a priority in the employer's systems for organizing work and in the worker's personal life. The NIOSH website has freely available online training programs with suggestions for workers and their managers to help them better cope with this workplace hazard.

  11. Attending physician work hours: ethical considerations and the last doctor standing.

    PubMed

    Mercurio, Mark R; Peterec, Steven M

    2009-08-01

    Based at least in part on concerns for patient safety and evidence that long shifts are associated with an increased risk of physician error, residents' and fellows' work hours have been strictly limited for the past several years. Little attention has been paid, however, to excessive attending physician shift duration, although there seems to be no reason to assume that this common practice poses any less risk to patients. Potential justifications for allowing attending physicians to work without hourly limits include physician autonomy, workforce shortages in certain communities or subspecialties, continuity of care, and financial considerations. None of these clearly justify the apparent increased risk to patients, with the exception in some settings of workforce shortage. In many hospital settings, the practice of allowing attending physicians to work with no limit on shift duration could pose an unnecessary risk to patients.

  12. Administrative work consumes one-sixth of U.S. physicians' working hours and lowers their career satisfaction.

    PubMed

    Woolhandler, Steffie; Himmelstein, David U

    2014-01-01

    Doctors often complain about the burden of administrative work, but few studies have quantified how much time clinicians devote to administrative tasks. We quantified the time U.S. physicians spent on administrative tasks, and its relationship to their career satisfaction, based on a nationally representative survey of 4,720 U.S. physicians working 20 or more hours per week in direct patient care. The average doctor spent 8.7 hours per week (16.6% of working hours) on administration. Psychiatrists spent the highest proportion of their time on administration (20.3%), followed by internists (17.3%) and family/general practitioners (17.3%). Pediatricians spent the least amount of time, 6.7 hours per week or 14.1 percent of professional time. Doctors in large practices, those in practices owned by a hospital, and those with financial incentives to reduce services spent more time on administration. More extensive use of electronic medical records was associated with a greater administrative burden. Doctors spending more time on administration had lower career satisfaction, even after controlling for income and other factors. Current trends in U.S. health policy--a shift to employment in large practices, the implementation of electronic medical records, and the increasing prevalence of financial risk sharing--are likely to increase doctors' paperwork burdens and may decrease their career satisfaction. PMID:25626223

  13. Influence of flexibility and variability of working hours on health and well-being.

    PubMed

    Costa, Giovanni; Sartori, Samantha; Akerstedt, Torbjorn

    2006-01-01

    Flexible working hours can have several meanings and can be arranged in a number of ways to suit the worker and/or employer. Two aspects of "flexible" arrangement of working hours were considered: one more subjected to company control and decision (variability) and one more connected to individual discretion and autonomy (flexibility). The aim of the study was to analyze these two dimensions in relation to health and well-being, taking into consideration the interaction with some relevant background variables related to demographics plus working and social conditions. The dataset of the Third European Survey on working conditions, conducted in 2000 and involving 21,505 workers, was used. Nineteen health disorders and four psycho-social conditions were tested by means of multiple logistic regression analysis, in which mutually adjusted odds ratios were calculated for age, gender, marital status, number of children, occupation, mode of employment, shift work, night work, time pressure, mental and physical workload, job satisfaction, and participation in work organization. The flexibility and variability of working hours appeared inversely related to health and psycho-social well-being: the most favorable effects were associated with higher flexibility and lower variability. The analysis of the interactions with the twelve intervening variables showed that physical work, age, and flexibility are the three most important factors affecting health and well-being. Flexibility resulted as the most important factor to influence work satisfaction; the second to affect family and social commitment and the ability to do the same job when 60 years old, as well as trauma, overall fatigue, irritability, and headache; and the third to influence heart disease, stomachache, anxiety, injury, and the feeling that health being at risk because of work. Variability was the third most important factor influencing family and social commitments. Moreover, shift and night work confirmed to

  14. Influence of flexibility and variability of working hours on health and well-being.

    PubMed

    Costa, Giovanni; Sartori, Samantha; Akerstedt, Torbjorn

    2006-01-01

    Flexible working hours can have several meanings and can be arranged in a number of ways to suit the worker and/or employer. Two aspects of "flexible" arrangement of working hours were considered: one more subjected to company control and decision (variability) and one more connected to individual discretion and autonomy (flexibility). The aim of the study was to analyze these two dimensions in relation to health and well-being, taking into consideration the interaction with some relevant background variables related to demographics plus working and social conditions. The dataset of the Third European Survey on working conditions, conducted in 2000 and involving 21,505 workers, was used. Nineteen health disorders and four psycho-social conditions were tested by means of multiple logistic regression analysis, in which mutually adjusted odds ratios were calculated for age, gender, marital status, number of children, occupation, mode of employment, shift work, night work, time pressure, mental and physical workload, job satisfaction, and participation in work organization. The flexibility and variability of working hours appeared inversely related to health and psycho-social well-being: the most favorable effects were associated with higher flexibility and lower variability. The analysis of the interactions with the twelve intervening variables showed that physical work, age, and flexibility are the three most important factors affecting health and well-being. Flexibility resulted as the most important factor to influence work satisfaction; the second to affect family and social commitment and the ability to do the same job when 60 years old, as well as trauma, overall fatigue, irritability, and headache; and the third to influence heart disease, stomachache, anxiety, injury, and the feeling that health being at risk because of work. Variability was the third most important factor influencing family and social commitments. Moreover, shift and night work confirmed to

  15. Long Working Hours and Coronary Heart Disease: A Systematic Review and Meta-Analysis

    PubMed Central

    Virtanen, Marianna; Heikkilä, Katriina; Jokela, Markus; Ferrie, Jane E.; Batty, G. David; Vahtera, Jussi; Kivimäki, Mika

    2012-01-01

    The authors aggregated the results of observational studies examining the association between long working hours and coronary heart disease (CHD). Data sources used were MEDLINE (through January 19, 2011) and Web of Science (through March 14, 2011). Two investigators independently extracted results from eligible studies. Heterogeneity between the studies was assessed using the I2 statistic, and the possibility of publication bias was assessed using the funnel plot and Egger's test for small-study effects. Twelve studies were identified (7 case-control, 4 prospective, and 1 cross-sectional). For a total of 22,518 participants (2,313 CHD cases), the minimally adjusted relative risk of CHD for long working hours was 1.80 (95% confidence interval (CI): 1.42, 2.29), and in the maximally (multivariate-) adjusted analysis the relative risk was 1.59 (95% CI: 1.23, 2.07). The 4 prospective studies produced a relative risk of 1.39 (95% CI: 1.12, 1.72), while the corresponding relative risk in the 7 case-control studies was 2.43 (95% CI: 1.81, 3.26). Little evidence of publication bias but relatively large heterogeneity was observed. Studies varied in size, design, measurement of exposure and outcome, and adjustments. In conclusion, results from prospective observational studies suggest an approximately 40% excess risk of CHD in employees working long hours. PMID:22952309

  16. The Effect of the Children's Health Insurance Program on Pediatricians' Work Hours

    PubMed Central

    He, Fang; White, Chapin

    2013-01-01

    Objective Our study examines changes in physicians' work hours in response to a coverage expansion. Methods We use as a natural experiment the Children's Health Insurance Program (CHIP), which was established in 1997 and significantly expanded children's eligibility for public health insurance coverage. The magnitude of the CHIP expansion varied across states and over time, allowing its effects to be identified using a state-year fixed effects model. We focus on pediatricians, and we measure their self-reported work hours using multiple waves (pre- and post-CHIP) of the physician survey component of the Community Tracking Study. To address endogeneity concerns, we instrument for CHIP enrollment using key program features (income eligibility cutoffs and waiting times). Results We find a large negative relationship between the magnitude of a state's CHIP expansion and trends in pediatricians' work hours. This relationship could be due to key supply-side features of CHIP, including relatively low provider reimbursements and heavy use of managed care tools. PMID:24753962

  17. Effect of work-hour restrictions and resident turnover in orthopedic trauma.

    PubMed

    Aynardi, Michael; Miller, Adam G; Orozco, Fabio; Ong, Alvin

    2012-11-01

    The resident 80-hour workweek and the July phenomenon have raised concern regarding the continuity of care of orthopedic patients in teaching institutions and its effect on postoperative complications and mortality. This study examined the effect of resident work-hour restrictions and the July phenomenon on patient outcomes after hip fracture at a large academic institution. Seven hundred twenty-two patients (mean age, 76.7 years) sustaining 319 femoral neck fractures and 403 intertrochanteric fractures between 2000 and 2010 were identified. Analysis was performed before and after July 1, 2003, as well as for the month of treatment. No difference existed in the postoperative outcome measures of delay of surgery (P=.061), complications (P=.904), and mortality (P=.981) between patients treated before and after July 1, 2003. Patients treated after July 1, 2003, had a significantly higher median number of preoperative comorbidities (4 vs 3, respectively; P<.0005). Turnover months, July and August, showed no difference in the outcome measures of delay of surgery (P=.171), complications (P=.776), and mortality (P=.524) compared with other months. This study suggests that 80-hour workweek restrictions or resident turnover months have no effect on patient care with respect to in-hospital time to surgery, complications, and mortality. This success can be attributed to ancillary staff support, physician extenders, and well-designed patient care protocols. PMID:23127459

  18. Fragmented care in the era of limited work hours: a plea for an explicit handover curriculum.

    PubMed

    Wohlauer, Max

    2012-12-01

    The current challenge in surgical residency education, preserving a sense of accountability in an era of limited work hours and multiple transitions of care, can be accomplished through the promotion of effective handovers. Approaches include increasing the transparency of handovers, enhancing the 'situational awareness' of individuals involved, and incorporating narratives and social interactions, and expanding common ground among professionals who collectively have responsibility for patient care. Done well, handovers can preserve the physician-patient relationship and provide a continuity bridge during a vulnerable time for patients. PMID:23173183

  19. Implementing the 2009 Institute of Medicine recommendations on resident physician work hours, supervision, and safety

    PubMed Central

    Blum, Alexander B; Shea, Sandra; Czeisler, Charles A; Landrigan, Christopher P; Leape, Lucian

    2011-01-01

    Long working hours and sleep deprivation have been a facet of physician training in the US since the advent of the modern residency system. However, the scientific evidence linking fatigue with deficits in human performance, accidents and errors in industries from aeronautics to medicine, nuclear power, and transportation has mounted over the last 40 years. This evidence has also spawned regulations to help ensure public safety across safety-sensitive industries, with the notable exception of medicine. In late 2007, at the behest of the US Congress, the Institute of Medicine embarked on a year-long examination of the scientific evidence linking resident physician sleep deprivation with clinical performance deficits and medical errors. The Institute of Medicine’s report, entitled “Resident duty hours: Enhancing sleep, supervision and safety”, published in January 2009, recommended new limits on resident physician work hours and workload, increased supervision, a heightened focus on resident physician safety, training in structured handovers and quality improvement, more rigorous external oversight of work hours and other aspects of residency training, and the identification of expanded funding sources necessary to implement the recommended reforms successfully and protect the public and resident physicians themselves from preventable harm. Given that resident physicians comprise almost a quarter of all physicians who work in hospitals, and that taxpayers, through Medicare and Medicaid, fund graduate medical education, the public has a deep investment in physician training. Patients expect to receive safe, high-quality care in the nation’s teaching hospitals. Because it is their safety that is at issue, their voices should be central in policy decisions affecting patient safety. It is likewise important to integrate the perspectives of resident physicians, policy makers, and other constituencies in designing new policies. However, since its release

  20. Implementing the 2009 Institute of Medicine recommendations on resident physician work hours, supervision, and safety

    PubMed Central

    Blum, Alexander B; Shea, Sandra; Czeisler, Charles A; Landrigan, Christopher P; Leape, Lucian

    2011-01-01

    Long working hours and sleep deprivation have been a facet of physician training in the US since the advent of the modern residency system. However, the scientific evidence linking fatigue with deficits in human performance, accidents and errors in industries from aeronautics to medicine, nuclear power, and transportation has mounted over the last 40 years. This evidence has also spawned regulations to help ensure public safety across safety-sensitive industries, with the notable exception of medicine. In late 2007, at the behest of the US Congress, the Institute of Medicine embarked on a year-long examination of the scientific evidence linking resident physician sleep deprivation with clinical performance deficits and medical errors. The Institute of Medicine’s report, entitled “Resident duty hours: Enhancing sleep, supervision and safety”, published in January 2009, recommended new limits on resident physician work hours and workload, increased supervision, a heightened focus on resident physician safety, training in structured handovers and quality improvement, more rigorous external oversight of work hours and other aspects of residency training, and the identification of expanded funding sources necessary to implement the recommended reforms successfully and protect the public and resident physicians themselves from preventable harm. Given that resident physicians comprise almost a quarter of all physicians who work in hospitals, and that taxpayers, through Medicare and Medicaid, fund graduate medical education, the public has a deep investment in physician training. Patients expect to receive safe, high-quality care in the nation’s teaching hospitals. Because it is their safety that is at issue, their voices should be central in policy decisions affecting patient safety. It is likewise important to integrate the perspectives of resident physicians, policy makers, and other constituencies in designing new policies. However, since its release

  1. Wages, Hours Of Work and Overtime Pay Provisions in Selected Industries, Ontario, April 1974. Employment Information Series No. 13.

    ERIC Educational Resources Information Center

    Ontario Dept. of Labour, Toronto. Research Branch.

    A survey was undertaken to obtain information on a number of working conditions including straight-time hourly earnings, weekly hours of work, and initial overtime provisions for nonsupervisory employees in selected Ontario industries. The purpose of the survey was to obtain data that would permit an assessment of the direct impact of proposed…

  2. The impact of overtime and long work hours on occupational injuries and illnesses: new evidence from the United States

    PubMed Central

    Dembe, A; Erickson, J; Delbos, R; Banks, S

    2005-01-01

    Aims: To analyse the impact of overtime and extended working hours on the risk of occupational injuries and illnesses among a nationally representative sample of working adults from the United States. Methods: Responses from 10 793 Americans participating in the National Longitudinal Survey of Youth (NLSY) were used to evaluate workers' job histories, work schedules, and occurrence of occupational injury and illness between 1987 and 2000. A total of 110 236 job records were analysed, encompassing 89 729 person-years of accumulated working time. Aggregated incidence rates in each of five exposure categories were calculated for each NLSY survey period. Multivariate analytical techniques were used to estimate the relative risk of long working hours per day, extended hours per week, long commute times, and overtime schedules on reporting a work related injury or illness, after adjusting for age, gender, occupation, industry, and region. Results: After adjusting for those factors, working in jobs with overtime schedules was associated with a 61% higher injury hazard rate compared to jobs without overtime. Working at least 12 hours per day was associated with a 37% increased hazard rate and working at least 60 hours per week was associated with a 23% increased hazard rate. A strong dose-response effect was observed, with the injury rate (per 100 accumulated worker-years in a particular schedule) increasing in correspondence to the number of hours per day (or per week) in the workers' customary schedule. Conclusions: Results suggest that job schedules with long working hours are not more risky merely because they are concentrated in inherently hazardous industries or occupations, or because people working long hours spend more total time "at risk" for a work injury. Strategies to prevent work injuries should consider changes in scheduling practices, job redesign, and health protection programmes for people working in jobs involving overtime and extended hours. PMID

  3. QCD with rooted staggered fermions

    NASA Astrophysics Data System (ADS)

    Goltermann, M.

    In this talk, I will give an overview of the theoretical status of staggered Lattice QCD with the “fourth-root trick.” In this regularization of QCD, a separate staggered quark field is used for each physical flavor, and the inherent four-fold multiplicity that comes with the use of staggered fermions is removed by taking the fourth root of the staggered determinant for each flavor. At nonzero lattice spacing, the resulting theory is nonlocal and not unitary, but there are now strong arguments that this disease is cured in the continuum limit. In addition, the approach to the continuum limit can be understood in detail in the framework of effective field theories such as staggered chiral perturbation theory.

  4. How to increase the burden on trauma centers: implement the 80-hour work week.

    PubMed

    Schroeppel, Thomas J; Sharpe, John P; Magnotti, Louis J; Weinberg, Jordan A; Croce, Martin A; Fabian, Timothy C

    2014-07-01

    The 80-hour week was implemented in 2003 to improve outcomes and limit errors. We hypothesize that there has been no change in outcomes postimplementation of the restrictions. Outcomes were queried from the trauma registry from 1997 to 2002 (PRE) and 2004 to 2009 (POST). Primary outcomes were mortality, intensive care unit length of stay (ICU LOS), and length of stay (LOS). Patients were stratified based on demographics, blood pressure, heart rate, and injury severity (Injury Severity Score, Glasgow Coma Score, base deficit). Outcomes were then compared PRE with POST. A total of 41,770 patients were admitted during the study period. The mean age was 38 years with most being male (73%) and blunt mechanism (78%). Although patients admitted in the POST period had a slightly higher blood pressure, they were older and had higher injury severity. ICU LOS, LOS, self-pay, and mortality were higher in the POST period. After adjusted analysis, admission in the POST period was no longer a predictor of mortality (odds ratio, 1.02; confidence interval, 0.92 to 1.14). Whereas patients were more slightly more injured in the POST period, the adjusted analysis shows no difference in mortality and both a longer LOS and ICU LOS. Whether the increase is the result of more severe injury in the POST period or less efficient disposition remains to be elucidated. This study adds to the mounting evidence that the implementation of the limits on work hours does not lead to better outcomes.

  5. Caring for Children 24/7, 365--Supporting Families Who Work Non-Traditional Hours.

    ERIC Educational Resources Information Center

    Acord, Phil

    2003-01-01

    Describes the Children's Home Extended Child Care Program in Tennessee, a year-round child-care program operating 24 hours a day. Presents considerations for programs contemplating extending their hours, including operation hours, ages of children served, staffing schedule, serving meals, cleaning the facility, facility security, and funding.…

  6. 29 CFR 553.230 - Maximum hours standards for work periods of 7 to 28 days-section 7(k).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-section 7(k). 553.230 Section 553.230 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR... Compensation Rules § 553.230 Maximum hours standards for work periods of 7 to 28 days—section 7(k). (a) For... 28 consecutive days, no overtime compensation is required under section 7(k) until the number...

  7. 29 CFR 5.15 - Limitations, variations, tolerances, and exemptions under the Contract Work Hours and Safety...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; and Johnston Island. (2) Agreements entered into by or on behalf of the Commodity Credit Corporation... deemed to be in violation of section 102 of the Contract Work Hour and Safety Standards Act for...

  8. The normal hourly variation of blood pressure in women: average patterns and the effect of work stress.

    PubMed

    James, G D; Moucha, O P; Pickering, T G

    1991-12-01

    The purpose of this study was to examine the pattern of diurnal variation of blood pressure in normotensive working women, and to assess the effect of work stress on this pattern. The subjects were 121 normotensive (based on clinic readings less than 140/90 mmHg) young women (age = 30.2 +/- 7.3 years; range 20-50) who wore an ambulatory blood pressure monitor on a workday from 9 am to 6 am the next day. The effect of work stress on the pattern of variation was assessed by comparing the hourly averages among women who perceived greater stress at work on the day of study ('work stressed') (n = 67) with those of women who perceived greater or equal stress at home on the day of study ('home stressed') (n = 54). The results showed that the systolic pressure of 'work stressed' women was 5-8 mmHg higher (P less than 0.05) and diastolic 3-4 mmHg higher (P less than 0.05) than 'home stressed' women for nearly every hour from 9 am to 6 pm. From 7 pm to 6 am, both groups were similar hour by hour. These data suggest that there is no intrinsic pattern of diurnal blood pressure variation (other than an awake-sleep cycle) in working women. The data also provide a reference standard for comparison with hypertensive women.

  9. Initial Learning in Mainstreaming Project: Off Base 10, Working with Hours, Minutes, Seconds.

    ERIC Educational Resources Information Center

    Tipton, Fern S.; Kingston, Neldon

    Developed by the Initial Learning in Mainstreaming Project, the manual presents an instructional program to teach mainstreamed handicapped elementary school students how to tell and compute time in terms of hours, minutes, and seconds. In addition to the basic time facts, the lessons cover carrying or borrowing with off-base-10 time facts, and…

  10. Schedule Control, Supervisor Support and Work Engagement: A Winning Combination for Workers in Hourly Jobs?

    ERIC Educational Resources Information Center

    Swanberg, Jennifer E.; McKechnie, Sharon P.; Ojha, Mamta U.; James, Jacquelyn B.

    2011-01-01

    The changing natures of both work and the lives of the U.S. workforce have created an array of challenges for organizations attempting to foster work engagement. To accommodate the work and family needs of an increasingly diverse workforce, many firms are offering flexible work solutions to employees. However, the distribution of these types of…

  11. How to Further Decrease the Efficiency of Care at a Level I Trauma Center: Implement the Amended Resident Work Hours.

    PubMed

    Schroeppel, Thomas J; Sharpe, John P; Magnotti, Louis J; Weinberg, Jordan A; Croce, Martin A; Fabian, Timothy C

    2015-07-01

    Work-hour restrictions were amended in 2011 to limit interns to 16 continuous duty hours, essentially requiring a night float system of 12-hour shifts. We hypothesize that there has been no improvement in outcomes after implementation of the amended work-hour restrictions. Outcomes from trauma admissions were queried from the trauma registry from 2009 to 2011 (PRE) and 2011 to 2013 (POST). The primary outcome was mortality with secondary outcomes intensive care unit length of stay (LOS)and LOS. Patients were stratified based on age, mechanism, gender, blood pressure, heart rate, and injury severity (Injury Severity Score, Glasgow Coma Scale, Base Deficit). Outcomes were then compared from admissions PRE to POST. A total of 9178 patients were included in the study population. The mean age was 42 with most being male (72%) and blunt mechanism (81%). Patient populations were well matched except patients in the POST period were slightly older (43 vs 42 years; P = 0.01). Intensive care unit LOS and LOS were higher in the POST period. After adjusted analysis, admission in the POST period was not a predictor of mortality (odds ratio 0.857; confidence interval 0.655-1.12). The POST period was an independent predictor for LOS (β = 0.74; P = 0.002). This study adds to the mounting evidence that the implementation of the amended limits on work hours leads to furthermore decreased efficiency of care.

  12. [Results of Training for Personnel Involved in Blood-Transfusion Testing Outside of Regular Work Hours at Saga University Hospital].

    PubMed

    Yamada, Marie; Yamada, Naotomo; Higashitani, Takanori; Ohta, Shoichiro; Sueoka, Eisaburo

    2015-11-01

    Laboratory testing prior to blood transfusion outside of regular hours in many hospitals and clinics is frequently conducted by technicians without sufficient experience in such testing work. To obtain consistent test results regardless of the degree of laboratory experience with blood transfusion testing, the number of facilities introducing automated equipment for testing prior to blood transfusion is increasing. Our hospital's blood transfusion department introduced fully automated test equipment in October of 2010 for use when blood transfusions are conducted outside of regular hours. However, excessive dependence on automated testing can lead to an inability to do manual blood typing or cross-match testing when necessitated by breakdowns in the automated test equipment, in the case of abnormal specimen reactions, or other such case. In addition, even outside of normal working hours there are more than a few instances in which transfusion must take place based on urgent communications from clinical staff, with the need for prompt and flexible timing of blood transfusion test and delivery of blood products. To address this situation, in 2010 we began training after-hours laboratory personnel in blood transfusion testing to provide practice using test tubes manually and to achieve greater understanding of blood transfusion test work (especially in cases of critical blood loss). Results of the training and difficulties in its implementation for such after-hours laboratory personnel at our hospital are presented and discussed in this paper. [Original

  13. The transition to parenthood and well-being: the impact of partner status and work hour transitions.

    PubMed

    Keizer, Renske; Dykstra, Pearl A; Poortman, Anne-Rigt

    2010-08-01

    Using data from the first two waves of the Netherlands Kinship Panel Study for 338 women and 262 men, we examine the consequences of making the transition to parenthood for life satisfaction, loneliness, positive affect, negative affect, and partnership satisfaction. We extend previous work by taking transitions in partner status and work hours into account. Results show a moderate impact of becoming a parent on well-being. In so far as effects of making the transition to parenthood emerge, they are attributable to changes in partner status and work hours. First, the decrease in negative affect upon making the transition to motherhood is attributable to the group of women who increase their working hours. Second, the detrimental impact of making the transition to motherhood on partnership satisfaction is attributable to the group of new mothers who quit their job. Third, the detrimental impact of making the transition to fatherhood on loneliness is attributable to the group of new fathers who become married. There is one exception to this pattern of partner status and work hours as mechanisms for changes in well-being. Men who become fathers remain less satisfied with their partnership, even when transitions in partner status and work hours have been taken into account. In the discussion-section, we consider the possible underestimation of negative effects because of the focus on the continuously partnered. We also reflect on our results in the light of the high incidence of part-time work in the Netherlands and Dutch policies aimed at supporting new parents.

  14. Risk of miscarriage and occupational activity: a systematic review and meta-analysis regarding shift work, working hours, lifting, standing and physical workload

    PubMed Central

    Bonde, Jens Peter E; Jørgensen, Kristian Tore; Bonzini, Matteo; Palmer, Keith T

    2013-01-01

    Objective Previous studies have indicated that shift work, long working hours and prevalent workplace exposures such as lifting, standing and physical workload increase the risk of miscarriage, but the evidence is conflicting. We conducted a systematic review of original research reports. Methods A search in Medline and EMBASE 1966 - 2012 identified 30 primary papers reporting the relative risk (RR) of miscarriage according to one or more of the five occupational activities of interest. Following an assessment of completeness of reporting, confounding and bias, each risk estimate was characterised as more or less likely to be biased. Studies with equivalent measures of exposure were pooled to obtain a weighted common risk estimate. Sensitivity analyses excluded studies most likely to be biased. Results Working fixed nights was associated with a moderately increased risk of miscarriage [pooled RR 1.51 (95% CI 1.27-1.78, n=5], while working in 3-shift schedules, working for >40 hours weekly, lifting>100 kg/day, standing > 6 hours/day and physical workload were associated with small risk increments, with the pooled RRs ranging from 1.12 (three shift schedule, n=7) to 1.36 (working hours, n=10). RRs for working hours and standing became smaller when analyses were restricted to higher quality studies. Conclusion These largely reassuring findings do not provide a strong case for mandatory restrictions in relation to shift work, long working hours, occupational lifting, standing and physical workload. Considering the limited evidence base, however, it may be prudent to advise women against work entailing high levels of these exposures and women with at-risk pregnancies should receive tailored individual counselling PMID:23235838

  15. Taste changing in staggered quarks

    SciTech Connect

    Quentin Mason et al.

    2004-01-05

    The authors present results from a systematic perturbative investigation of taste-changing in improved staggered quarks. They show one-loop taste-changing interactions can be removed perturbatively by an effective four-quark term and calculate the necessary coefficients.

  16. Cross-National Differences in the Association between Parental Work Hours and Time with Children in Europe: A Multilevel Analysis

    ERIC Educational Resources Information Center

    Roeters, Anne

    2013-01-01

    This study investigates cross-national differences in the association between parental work hours and parent-child interaction time and explains differences in this individual-level association on the basis of country characteristics. It extends prior research by testing the moderating effects of country characteristics through multilevel analyses…

  17. 48 CFR 852.222-70 - Contract Work Hours and Safety Standards Act-nursing home care contract supplement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Safety Standards Act-nursing home care contract supplement. 852.222-70 Section 852.222-70 Federal...—nursing home care contract supplement. As prescribed in 822.305, for nursing home care requirements, insert the following clause: Contract Work Hours and Safety Standards Act—Nursing Home Care...

  18. 48 CFR 852.222-70 - Contract Work Hours and Safety Standards Act-nursing home care contract supplement.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Safety Standards Act-nursing home care contract supplement. 852.222-70 Section 852.222-70 Federal...—nursing home care contract supplement. As prescribed in 822.305, for nursing home care requirements, insert the following clause: Contract Work Hours and Safety Standards Act—Nursing Home Care...

  19. 48 CFR 852.222-70 - Contract Work Hours and Safety Standards Act-nursing home care contract supplement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Safety Standards Act-nursing home care contract supplement. 852.222-70 Section 852.222-70 Federal...—nursing home care contract supplement. As prescribed in 822.305, for nursing home care requirements, insert the following clause: Contract Work Hours and Safety Standards Act—Nursing Home Care...

  20. 48 CFR 852.222-70 - Contract Work Hours and Safety Standards Act-nursing home care contract supplement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Safety Standards Act-nursing home care contract supplement. 852.222-70 Section 852.222-70 Federal...—nursing home care contract supplement. As prescribed in 822.305, for nursing home care requirements, insert the following clause: Contract Work Hours and Safety Standards Act—Nursing Home Care...

  1. 48 CFR 852.222-70 - Contract Work Hours and Safety Standards Act-nursing home care contract supplement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Safety Standards Act-nursing home care contract supplement. 852.222-70 Section 852.222-70 Federal...—nursing home care contract supplement. As prescribed in 822.305, for nursing home care requirements, insert the following clause: Contract Work Hours and Safety Standards Act—Nursing Home Care...

  2. On staggered indecomposable Virasoro modules

    NASA Astrophysics Data System (ADS)

    Kytölä, Kalle; Ridout, David

    2009-12-01

    In this article, certain indecomposable Virasoro modules are studied. Specifically, the Virasoro mode L0 is assumed to be nondiagonalizable, possessing Jordan blocks of rank 2. Moreover, the module is further assumed to have a highest weight submodule, the "left module," and that the quotient by this submodule yields another highest weight module, the "right module." Such modules, which have been called staggered, have appeared repeatedly in the logarithmic conformal field theory literature, but their theory has not been explored in full generality. Here, such a theory is developed for the Virasoro algebra using rather elementary techniques. The focus centers on two different but related questions typically encountered in practical studies: How can one identify a given staggered module, and how can one demonstrate the existence of a proposed staggered module. Given just the values of the highest weights of the left and right modules, themselves subject to simple necessary conditions, invariants are defined which together with the knowledge of the left and right modules uniquely identify a staggered module. The possible values of these invariants form a vector space of dimension 0, 1, or 2, and the structures of the left and right modules limit the isomorphism classes of the corresponding staggered modules to an affine subspace (possibly empty). The number of invariants and affine restrictions is purely determined by the structures of the left and right modules. Moreover, in order to facilitate applications, the expressions for the invariants and restrictions are given by formulas as explicit as possible (they generally rely on expressions for Virasoro singular vectors). Finally, the text is liberally peppered throughout with examples illustrating the general concepts. These have been carefully chosen for their physical relevance or for the novel features they exhibit.

  3. Training for the future NHS: training junior doctors in the United Kingdom within the 48-hour European working time directive

    PubMed Central

    2014-01-01

    Since August 2009, the National Health Service of the United Kingdom has faced the challenge of delivering training for junior doctors within a 48-hour working week, as stipulated by the European Working Time Directive and legislated in the UK by the Working Time Regulations 1998. Since that time, widespread concern has been expressed about the impact of restricted duty hours on the quality of postgraduate medical training in the UK, particularly in the “craft” specialties – that is, those disciplines in which trainees develop practical skills that are best learned through direct experience with patients. At the same time, specialist training in the UK has experienced considerable change since 2007 with the introduction of competency-based specialty curricula, workplace-based assessment, and the annual review of competency progression. The challenges presented by the reduction of duty hours include increased pressure on doctors-in-training to provide service during evening and overnight hours, reduced interaction with supervisors, and reduced opportunities for learning. This paper explores these challenges and proposes potential responses with respect to the reorganization of training and service provision. PMID:25560369

  4. Training for the future NHS: training junior doctors in the United Kingdom within the 48-hour European working time directive.

    PubMed

    Datta, Shreelatta T; Davies, Sally J

    2014-01-01

    Since August 2009, the National Health Service of the United Kingdom has faced the challenge of delivering training for junior doctors within a 48-hour working week, as stipulated by the European Working Time Directive and legislated in the UK by the Working Time Regulations 1998. Since that time, widespread concern has been expressed about the impact of restricted duty hours on the quality of postgraduate medical training in the UK, particularly in the "craft" specialties--that is, those disciplines in which trainees develop practical skills that are best learned through direct experience with patients. At the same time, specialist training in the UK has experienced considerable change since 2007 with the introduction of competency-based specialty curricula, workplace-based assessment, and the annual review of competency progression. The challenges presented by the reduction of duty hours include increased pressure on doctors-in-training to provide service during evening and overnight hours, reduced interaction with supervisors, and reduced opportunities for learning. This paper explores these challenges and proposes potential responses with respect to the reorganization of training and service provision. PMID:25560369

  5. 48 CFR 52.222-4 - Contract Work Hours and Safety Standards-Overtime Compensation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CFR 5.5(a)(3) implementing the Construction Wage Rate Requirements statute. (2) The Contractor and its... laborers or mechanics (see Federal Acquisition Regulation 22.300) shall require or permit them to work over... basic payroll records for all laborers and mechanics working on the contract during the contract...

  6. 48 CFR 52.222-4 - Contract Work Hours and Safety Standards Act-Overtime Compensation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... duplicate those required for construction work by Department of Labor regulations at 29 CFR 5.5(a)(3... employing laborers or mechanics (see Federal Acquisition Regulation 22.300) shall require or permit them to... all laborers and mechanics working on the contract during the contract and shall make them...

  7. 48 CFR 52.222-4 - Contract Work Hours and Safety Standards Act-Overtime Compensation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... duplicate those required for construction work by Department of Labor regulations at 29 CFR 5.5(a)(3... employing laborers or mechanics (see Federal Acquisition Regulation 22.300) shall require or permit them to... all laborers and mechanics working on the contract during the contract and shall make them...

  8. 48 CFR 52.222-4 - Contract Work Hours and Safety Standards Act-Overtime Compensation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... duplicate those required for construction work by Department of Labor regulations at 29 CFR 5.5(a)(3... employing laborers or mechanics (see Federal Acquisition Regulation 22.300) shall require or permit them to... all laborers and mechanics working on the contract during the contract and shall make them...

  9. Heavy-light semileptonic decays in staggered chiral perturbation theory

    NASA Astrophysics Data System (ADS)

    Aubin, C.; Bernard, C.

    2007-07-01

    We calculate the form factors for the semileptonic decays of heavy-light pseudoscalar mesons in partially quenched staggered chiral perturbation theory (SχPT), working to leading order in 1/mQ, where mQ is the heavy-quark mass. We take the light meson in the final state to be a pseudoscalar corresponding to the exact chiral symmetry of staggered quarks. The treatment assumes the validity of the standard prescription for representing the staggered “fourth-root trick” within SχPT by insertions of factors of 1/4 for each sea-quark loop. Our calculation is based on an existing partially quenched continuum chiral perturbation theory calculation with degenerate sea quarks by Bećirević, Prelovsek, and Zupan, which we generalize to the staggered (and nondegenerate) case. As a byproduct, we obtain the continuum partially quenched results with nondegenerate sea quarks. We analyze the effects of nonleading chiral terms, and find a relation among the coefficients governing the analytic valence mass dependence at this order. Our results are useful in analyzing lattice computations of form factors B→π and D→K, when the light quarks are simulated with the staggered action.

  10. When Twenty-Four Hours Is Not Enough: Time Poverty of Working Parents

    ERIC Educational Resources Information Center

    Harvey, Andrew S.; Mukhopadhyay, Arun K.

    2007-01-01

    Individuals can be money poor, time poor or both. While income is the most used indicator of poverty, broader indexes including non-monetary aspects of deprivation have been proposed and measured. As one such measure, our study focuses on the element of deprivation arising from the time deficit of many working people. The usual poverty threshold…

  11. The Effect of Taxation on the Hours Worked by Married Women.

    ERIC Educational Resources Information Center

    Leuthold, Jane H.

    1978-01-01

    Using data from the National Longitudinal Survey of women between 1967 and 1971, the author concludes that tax increases have a negative effect on the labor supply of married working women. Among the factors examined were presence of preschool children, husband's approval, home ownership, health, and educational background. (MF)

  12. Is health, measured by work ability index, affected by 12-hour rotating shift schedules?

    PubMed

    Yong, Mei; Nasterlack, Michael; Pluto, Rolf-Peter; Elmerich, Kathrin; Karl, Dorothee; Knauth, Peter

    2010-07-01

    Two forms of continuously forward rotating 12-h shift schedules exist at BASF's Ludwigshafen site. These shift schedules were compared with a daytime working system to investigate potential differential effects on employee's health status assessed with the Work Ability Index (WAI). In the 3 x 12 system, a 12-h day shift is followed 24 h later by a 12-h night shift, and after a day off the employee returns to the day shift. The 4 x 12 schedule follows the same pattern except that there are 2 days off between the night and next day shift. A total of 924 participants (278 3 x 12 and 321 4 x 12 shiftworkers and 325 day workers) were recruited. A self-administered questionnaire was used to obtain information about shiftwork schedule, demographic characteristics, and lifestyle and social factors, and the WAI was applied. The outcomes of interest were the WAI sum score and its seven dimensions. In examining the relationship with the WAI categories, a Proportional Odds Model (POM) was used to identify the potential determinants. Logistic regression models were used to estimate the impact of age on single dimensions of WAI after adjustment for potential confounding factors. Increasing age and obesity (BMI > or = 30) were the only significant determinants of poorer WAI. Although a positive association was found linking the second WAI dimension (work ability in relation to job demands) with age, an inverse association was demonstrated consistently between age and the third and fourth WAI dimensions, i.e., number of diagnosed diseases and estimated work impairment due to disease, after adjustment for potential confounders. The age-dependency was moderate overall, but seemed to be stronger among shift- than day workers, although this difference did not reach statistical significance. There was no significant differential impact of the working time systems on the WAI sum score or on the individual WAI dimensions. Thus, there is no indication of an excessive adverse health impact

  13. Is health, measured by work ability index, affected by 12-hour rotating shift schedules?

    PubMed

    Yong, Mei; Nasterlack, Michael; Pluto, Rolf-Peter; Elmerich, Kathrin; Karl, Dorothee; Knauth, Peter

    2010-07-01

    Two forms of continuously forward rotating 12-h shift schedules exist at BASF's Ludwigshafen site. These shift schedules were compared with a daytime working system to investigate potential differential effects on employee's health status assessed with the Work Ability Index (WAI). In the 3 x 12 system, a 12-h day shift is followed 24 h later by a 12-h night shift, and after a day off the employee returns to the day shift. The 4 x 12 schedule follows the same pattern except that there are 2 days off between the night and next day shift. A total of 924 participants (278 3 x 12 and 321 4 x 12 shiftworkers and 325 day workers) were recruited. A self-administered questionnaire was used to obtain information about shiftwork schedule, demographic characteristics, and lifestyle and social factors, and the WAI was applied. The outcomes of interest were the WAI sum score and its seven dimensions. In examining the relationship with the WAI categories, a Proportional Odds Model (POM) was used to identify the potential determinants. Logistic regression models were used to estimate the impact of age on single dimensions of WAI after adjustment for potential confounding factors. Increasing age and obesity (BMI > or = 30) were the only significant determinants of poorer WAI. Although a positive association was found linking the second WAI dimension (work ability in relation to job demands) with age, an inverse association was demonstrated consistently between age and the third and fourth WAI dimensions, i.e., number of diagnosed diseases and estimated work impairment due to disease, after adjustment for potential confounders. The age-dependency was moderate overall, but seemed to be stronger among shift- than day workers, although this difference did not reach statistical significance. There was no significant differential impact of the working time systems on the WAI sum score or on the individual WAI dimensions. Thus, there is no indication of an excessive adverse health impact

  14. 29 CFR 553.230 - Maximum hours standards for work periods of 7 to 28 days-section 7(k).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Maximum hours standards for work periods of 7 to 28 days... Fire protection Law enforcement 28 212 171 27 204 165 26 197 159 25 189 153 24 182 147 23 174 141 22 167 134 21 159 128 20 151 122 19 144 116 18 136 110 17 129 104 16 121 98 15 114 92 14 106 86 13 98...

  15. 29 CFR 553.230 - Maximum hours standards for work periods of 7 to 28 days-section 7(k).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Maximum hours standards for work periods of 7 to 28 days... Fire protection Law enforcement 28 212 171 27 204 165 26 197 159 25 189 153 24 182 147 23 174 141 22 167 134 21 159 128 20 151 122 19 144 116 18 136 110 17 129 104 16 121 98 15 114 92 14 106 86 13 98...

  16. 29 CFR 553.230 - Maximum hours standards for work periods of 7 to 28 days-section 7(k).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Maximum hours standards for work periods of 7 to 28 days... Fire protection Law enforcement 28 212 171 27 204 165 26 197 159 25 189 153 24 182 147 23 174 141 22 167 134 21 159 128 20 151 122 19 144 116 18 136 110 17 129 104 16 121 98 15 114 92 14 106 86 13 98...

  17. Staggered chiral perturbation theory for heavy-light mesons

    NASA Astrophysics Data System (ADS)

    Aubin, C.; Bernard, C.

    2006-01-01

    We incorporate heavy-light mesons into staggered chiral perturbation theory (SχPT), working to leading order in 1/mQ, where mQ is the heavy-quark mass. At first nontrivial order in the chiral expansion, staggered taste violations affect the chiral logarithms for heavy-light quantities only through the light-meson propagators in loops. There are also new analytic contributions coming from additional terms in the Lagrangian involving heavy-light and light mesons. Using this heavy-light SχPT, we perform the one-loop calculation of the B (or D) meson leptonic decay constant in the partially quenched and full QCD cases. In our treatment, we assume the validity both of the “fourth root trick” to reduce four staggered tastes to one, and of the SχPT prescription to represent this trick by insertions of factors of 1/4 for each sea-quark loop.

  18. Stiffness of the Extrafibrillar Phase in Staggered Biological Arrays

    NASA Astrophysics Data System (ADS)

    Bar-On, Benny; Wagner, H. Daniel

    2012-08-01

    A number of important biological tissues such as nacre, tendon, and bone consist of staggered structural arrays as universal motifs. Such arrays usually include stiff fibril-like (or plateletlike, or needlelike) elements embedded in an extrafibrillar (XF) phase. This work discusses the effect of the stiffness of such an XF matrix on the elastic properties of the resulting staggered composite. In the case of most biological composites, this XF stiffness is hardly accessible and very little data are available. We develop an analysis based on previous analytical formulation that results in a relation between the XF modulus and the deformations of the staggered particles. This analysis is then used to back-calculate the yet unmeasured modulus of the XF phase from experimental deformation data, thereby providing a simple alternative to potentially complex direct measurements. This is demonstrated and validated for parallel-fiber bone tissue.

  19. Stiffness of the extrafibrillar phase in staggered biological arrays.

    PubMed

    Bar-On, Benny; Wagner, H Daniel

    2012-08-17

    A number of important biological tissues such as nacre, tendon, and bone consist of staggered structural arrays as universal motifs. Such arrays usually include stiff fibril-like (or plateletlike, or needlelike) elements embedded in an extrafibrillar (XF) phase. This work discusses the effect of the stiffness of such an XF matrix on the elastic properties of the resulting staggered composite. In the case of most biological composites, this XF stiffness is hardly accessible and very little data are available. We develop an analysis based on previous analytical formulation that results in a relation between the XF modulus and the deformations of the staggered particles. This analysis is then used to back-calculate the yet unmeasured modulus of the XF phase from experimental deformation data, thereby providing a simple alternative to potentially complex direct measurements. This is demonstrated and validated for parallel-fiber bone tissue. PMID:23006404

  20. Effects of pay resets following drug use on attendance and hours worked in a therapeutic workplace.

    PubMed

    Holtyn, August F; Silverman, Kenneth

    2016-06-01

    This secondary data analysis examined effects of an abstinence contingency on participation in a therapeutic workplace. Participants exposed to a pay reset after drug use did not differ in overall attendance from participants who were not exposed to a pay reset after drug use; however, they initially worked less after a pay reset than participants who did not receive a pay reset, and their attendance increased as their pay increased. Overall participation was not influenced by the abstinence contingency, but transient decreases in attendance occurred.

  1. 24-hour pattern of work-related injury risk of French firemen: nocturnal peak time.

    PubMed

    Riedel, Marc; Berrez, Stéphane; Pelisse, Didier; Brousse, Eric; Forget, Coralie; Marlot, Michel; Smolensky, Michael H; Touitou, Yvan; Reinberg, Alain

    2011-10-01

    The first aim of the study was to assess clock-time patterning of work-related injuries (WRIs) of firemen (FM) of Saône et Loire-71 (France) during the 4-yr span of 1 January 2004 to 31 December 2007. FM of this service are legally required to log every WRI and seek its evaluation by the medical service, whether the WRI was the result of worksite duties or exercise/sport activities at the station. WRI was defined specifically as a (nonexercise, nonsport, and nonemotional/stress) work-associated trauma, verified both by log book and medical records. For the corresponding years, the 24-h pattern of emergency calls (Calls) plus road traffic (Traffic) on the main roads of the service area was also assessed. Relative risk (R) of WRI was calculated as the quantity of WRIs/h divided by the quantity of Call responses/h × 1000, which takes into account the number of at-risk FM/unit time, since each dispatched emergency vehicle is staffed with 4 FM. Comparably trained regular (RFM) and volunteer (VFM) FM experienced a total of 187 WRIs. The 24-h WRI curve patterns of RFM and VFM were correlated (r = 0.4, p < .05), with no histogram difference (p > .05). Analysis of variance (ANOVA) validated comparable clock-time patterns in WRIs of RFM and VFM each year and each season (all p < .0001). Thus, time series of the RFM and VFM were pooled, revealing a statistical significant 24-h variation in WRIs (ANOVA, p > .0006; Cosinor analysis, p < .0001), with peak at 16:00 h and trough at 04:00 h. The 24-h pattern in Traffic, which mirrors that of human activity, with peak ∼18:00 h and trough ∼03:00 h, was also verified (ANOVA, p < .0001; Cosinor, p < .0001). Calls (n = 112,059) resulting in FM responses also exhibited statistically significant 24-h variation, with peak at ∼20:00 h and trough at ∼06:00 h. The 24-h pattern of R showed a nocturnal peak at 02:00 h (R = 2.87 ± 0.46; mean ± SEM) and diurnal trough 14

  2. Staggered fermion matrix elements using smeared operators

    NASA Astrophysics Data System (ADS)

    Kilcup, Greg; Gupta, Rajan; Sharpe, Stephen R.

    1998-02-01

    We investigate the use of two kinds of staggered fermion operators, smeared and unsmeared. The smeared operators extend over a 44 hypercube, and tend to have smaller perturbative corrections than the corresponding unsmeared operators. We use these operators to calculate kaon weak matrix elements on quenched ensembles at β=6.0, 6.2, and 6.4. Extrapolating to the continuum limit, we find BK(NDR,2 GeV)=0.62+/-0.02(stat)+/-0.02(syst). The systematic error is dominated by the uncertainty in the matching between lattice and continuum operators due to the truncation of perturbation theory at one loop. We do not include any estimate of the errors due to quenching or to the use of degenerate s and d quarks. For the ΔI=3/2 electromagnetic penguin operators we find B(3/2)7=0.62+/-0.03+/-0.06 and B(3/2)8=0.77+/-0.04+/-0.04. We also use the ratio of unsmeared to smeared operators to make a partially nonperturbative estimate of the renormalization of the quark mass for staggered fermions. We find that tadpole improved perturbation theory works well if the coupling is chosen to be αMS¯(q*=1/a).

  3. Ozone, Electrostatic Precipitators, and Particle Number Concentrations: Correlations Observed in a Real Office during Working Hours.

    PubMed

    Xiang, Jianbang; Weschler, Charles J; Mo, Jinhan; Day, Drew; Zhang, Junfeng; Zhang, Yinping

    2016-09-20

    This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed. PMID:27571436

  4. Ozone, Electrostatic Precipitators, and Particle Number Concentrations: Correlations Observed in a Real Office during Working Hours.

    PubMed

    Xiang, Jianbang; Weschler, Charles J; Mo, Jinhan; Day, Drew; Zhang, Junfeng; Zhang, Yinping

    2016-09-20

    This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed.

  5. Weekly working hours for Norwegian hospital doctors since 1994 with special attention to postgraduate training, work–home balance and the European Working Time Directive: a panel study

    PubMed Central

    Rosta, Judith; Aasland, Olaf G

    2014-01-01

    Objectives To examine the weekly working hours of Norwegian hospital doctors from 1994 to 2012 with special emphasis on the quality of postgraduate training and work–home balance, and in relation to the requirements of the European Working Time Directive (EWTD). Design Panel study based on postal questionnaires. Setting Norway. Participants Unbalanced cohort of 1300–1600 doctors in 1994, 1995, 1996, 1997, 2000, 2002, 2004, 2006, 2008, 2010 and 2012. Outcome measures Self-reported total weekly working hours and whether 45 weekly working hours are too short, sufficient, or too long to meet the quality requirements of obligatory postgraduate training for junior doctors. Results From 1994 to 2012, the number of weekly working hours was stable for senior (46–47 h) and junior (45–46 h) hospital doctors. In 2012, significantly more senior (27–35%) than junior (11–20%) doctors reported suboptimal work–home balance, defined as working more than 48 h a week. The majority perceived the present situation with an average of 45 h per week for juniors as sufficient for obligatory postgraduate specialist training, but doctors of higher age (OR 1.04, 95% CI 1.01 to 1.08), senior doctors (1.07, 1.04 to 1.11) and doctors working in surgical specialties (OR 1 vs laboratory medicine 0.03, 0.01 to 0.25, internal medicine 0.31, 0.17 to 0.58, psychiatry 0.12, 0.04 to 0.36, paediatrics 0.36, 0.12 to 1.07, anaesthesiology 0.08, 0.02 to 0.39, gynaecology 0.07, 0.01 to 0.56 and others 0.39, 0.04 to 3.56) were more likely to want the work-week to be longer. Conclusions The weekly working hours of Norwegian hospital doctors were always below the EWTD requirements. A significant growth of hospital doctor density over the past two decades, national regulations and cultural values might be important factors. Specialty differences in perception of sufficient training time may call for more flexibility in working time regulations. PMID:25311038

  6. Reply to 'Comment on ''t Hooft vertices, partial quenching, and rooted staggered QCD''

    SciTech Connect

    Bernard, Claude; Golterman, Maarten; Shamir, Yigal; Sharpe, Stephen R.

    2008-10-01

    We reply to Creutz's comments on our paper ''t Hooft vertices, partial quenching, and rooted staggered QCD'. We show that his criticisms are incorrect and result from a misunderstanding both of our work, and of the related work of Adams.

  7. Self-Reported Recovery from 2-Week 12-Hour Shift Work Schedules: A 14-Day Follow-Up

    PubMed Central

    Merkus, Suzanne L.; Holte, Kari Anne; Huysmans, Maaike A.; van de Ven, Peter M.; van Mechelen, Willem; van der Beek, Allard J.

    2015-01-01

    Background Recovery from fatigue is important in maintaining night workers' health. This study compared the course of self-reported recovery after 2-week 12-hour schedules consisting of either night shifts or swing shifts (i.e., 7 night shifts followed by 7 day shifts) to such schedules consisting of only day work. Methods Sixty-one male offshore employees—20 night workers, 16 swing shift workers, and 25 day workers—rated six questions on fatigue (sleep quality, feeling rested, physical and mental fatigue, and energy levels; scale 1–11) for 14 days after an offshore tour. After the two night-work schedules, differences on the 1st day (main effects) and differences during the follow-up (interaction effects) were compared to day work with generalized estimating equations analysis. Results After adjustment for confounders, significant main effects were found for sleep quality for night workers (1.41, 95% confidence interval 1.05–1.89) and swing shift workers (1.42, 95% confidence interval 1.03–1.94) when compared to day workers; their interaction terms were not statistically significant. For the remaining fatigue outcomes, no statistically significant main or interaction effects were found. Conclusion After 2-week 12-hour night and swing shifts, only the course for sleep quality differed from that of day work. Sleep quality was poorer for night and swing shift workers on the 1st day off and remained poorer for the 14-day follow-up. This showed that while working at night had no effect on feeling rested, tiredness, and energy levels, it had a relatively long-lasting effect on sleep quality. PMID:26929834

  8. Associations of Work Hours, Job Strain, and Occupation with Endothelial Function: The Multi-Ethnic Study of Atherosclerosis (MESA)

    PubMed Central

    Charles, Luenda E.; Fekedulegn, Desta; Landsbergis, Paul; Burchfiel, Cecil M.; Baron, Sherry; Kaufman, Joel D.; Stukovsky, Karen Hinckley; Fujishiro, Kaori; Foy, Capri G.; Andrew, Michael E.; Roux, Ana V. Diez

    2014-01-01

    Objective To investigate associations of work hours, job control, job demands, job strain, and occupational category with brachial artery flow-mediated dilation (FMD) in 1,499 MESA participants. Methods FMD was obtained using high-resolution ultrasound. Mean values of FMD were examined across categories of occupation, work hours, and the other exposures using regression analyses. Results Occupational category was significantly associated with FMD overall, with blue-collar workers showing the lowest mean values: Management/professional=4.97±0.22%; sales/office=5.19±0.28%; services=4.73 ± 0.29%; and blue-collar workers=4.01±0.26% (adjusted P <0.001). There was evidence of effect modification by gender (interaction P=0.031): significant associations were observed among women (adjusted P =0.002) and nearly significant results among men (adjusted P=0.087). Other exposures were not significantly associated with FMD. Conclusions Differences in endothelial function may account for some of the variation in cardiovascular disease across occupational groups. PMID:25376409

  9. Company Policies on Working Hours and Night Work in Relation to Older Workers' Work Ability and Work Engagement: Results From a Dutch Longitudinal Study with 2 Year Follow-Up.

    PubMed

    van der Meer, Laudry; Leijten, Fenna R M; Heuvel, Swenneke G; Ybema, Jan F; de Wind, Astrid; Burdorf, Alex; Geuskens, Goedele A

    2016-06-01

    Purpose To longitudinally investigate (1) whether lower work ability and work engagement predict the use of company policies on reduced working hours and exemption from evening/night work among older workers, and (2) whether using such policies subsequently contribute to higher work ability and work engagement. Methods In total 6922 employees (45-64 years) participating in the first three waves of the Study on Transitions in Employment, Ability and Motivation were included. Participants yearly filled out an online questionnaires. Regression analyses were applied to study the influence of baseline work ability and work engagement on the incident use of policies during the first year of follow-up, and the incident use of these policies on work ability and work engagement during the second year of follow-up. Results Employees with a higher work ability were less likely to start using the policy 'reduced working hours' [OR 0.91 (95 % CI 0.83-0.98)]. Starting to use this policy was in turn related to lower work ability 1 year later [B -0.28 (95 % CI -0.47 to -0.08)]. Starting to use the policy 'exemption from evening/night work' was related to higher work engagement 1 year later [B 0.23 (95 % CI 0.07-0.39)]. Conclusions Low work ability precedes the use of some company policies aiming to support sustainable employability of older workers. Further research is needed to explore whether company policies result in a (longstanding) improvement, or reduced deterioration, of older workers' employability.

  10. Company Policies on Working Hours and Night Work in Relation to Older Workers' Work Ability and Work Engagement: Results From a Dutch Longitudinal Study with 2 Year Follow-Up.

    PubMed

    van der Meer, Laudry; Leijten, Fenna R M; Heuvel, Swenneke G; Ybema, Jan F; de Wind, Astrid; Burdorf, Alex; Geuskens, Goedele A

    2016-06-01

    Purpose To longitudinally investigate (1) whether lower work ability and work engagement predict the use of company policies on reduced working hours and exemption from evening/night work among older workers, and (2) whether using such policies subsequently contribute to higher work ability and work engagement. Methods In total 6922 employees (45-64 years) participating in the first three waves of the Study on Transitions in Employment, Ability and Motivation were included. Participants yearly filled out an online questionnaires. Regression analyses were applied to study the influence of baseline work ability and work engagement on the incident use of policies during the first year of follow-up, and the incident use of these policies on work ability and work engagement during the second year of follow-up. Results Employees with a higher work ability were less likely to start using the policy 'reduced working hours' [OR 0.91 (95 % CI 0.83-0.98)]. Starting to use this policy was in turn related to lower work ability 1 year later [B -0.28 (95 % CI -0.47 to -0.08)]. Starting to use the policy 'exemption from evening/night work' was related to higher work engagement 1 year later [B 0.23 (95 % CI 0.07-0.39)]. Conclusions Low work ability precedes the use of some company policies aiming to support sustainable employability of older workers. Further research is needed to explore whether company policies result in a (longstanding) improvement, or reduced deterioration, of older workers' employability. PMID:26250870

  11. Elevated blood pressure, decreased heart rate variability and incomplete blood pressure recovery after a 12-hour night shift work.

    PubMed

    Su, Ta-Chen; Lin, Lian-Yu; Baker, Dean; Schnall, Peter L; Chen, Ming-Fong; Hwang, Wen-Chang; Chen, Chen-Fang; Wang, Jung-Der

    2008-01-01

    Shift work has been associated with increased risk of cardiovascular disease. This study was designed to determine the hemodynamic effects of 12-hour (12-h) shifts, and changes in blood pressure (BP) and heart rate variability (HRV) during 36 h rest time following 12-h shifts. Fifteen male shift workers with a mean age of 32.9 yr were recruited from a semiconductor factory. Ambulatory BP (AmBP) monitoring was performed for a total of 48 h for each participant. Six workers were monitored for 48 h by Holter electrocardiogram on both the day and night shifts. Paired self-comparison was used to estimate the difference between two hourly measurements of 12-h BP, HR, and HRV using the same timetable intra-individually. We also applied mixed models to estimate the effects of 12-h shifts on the delayed recovery of BP and heart rate (HR) in six workers who completed 96-h AmBP monitoring, including a 48-h night shift-rest period and another day shift period. Results showed that 12-h night shift work gave a persistently elevated systolic and diastolic BP (SBP and DBP) and HR, and decreased HRV compared to 12-h day shift work with the corresponding resting time. In addition, there was delayed SBP and DBP recovery on the first 12-h rest time in night shift workers, which was further demonstrated on the second 12-h rest time after adjustment for possible confounders through mixed models. In conclusion, 12-h night shift work may elevate BP and HR and decrease HRV. It is also associated with delayed BP recovery.

  12. 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.

  13. 45 CFR 261.60 - What hours of participation may a State report for a work-eligible individual?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Verification Plan. (e) A State may count supervised homework time and up to one hour of unsupervised homework time for each hour of class time. Total homework time counted for participation cannot exceed the...

  14. 45 CFR 261.60 - What hours of participation may a State report for a work-eligible individual?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Verification Plan. (e) A State may count supervised homework time and up to one hour of unsupervised homework time for each hour of class time. Total homework time counted for participation cannot exceed the...

  15. 45 CFR 261.60 - What hours of participation may a State report for a work-eligible individual?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Verification Plan. (e) A State may count supervised homework time and up to one hour of unsupervised homework time for each hour of class time. Total homework time counted for participation cannot exceed the...

  16. 45 CFR 261.60 - What hours of participation may a State report for a work-eligible individual?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Verification Plan. (e) A State may count supervised homework time and up to one hour of unsupervised homework time for each hour of class time. Total homework time counted for participation cannot exceed the...

  17. 45 CFR 261.60 - What hours of participation may a State report for a work-eligible individual?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Verification Plan. (e) A State may count supervised homework time and up to one hour of unsupervised homework time for each hour of class time. Total homework time counted for participation cannot exceed the...

  18. Working hours, sleep, salivary cortisol, fatigue and neuro-behavior during Mars analog mission: five crews study.

    PubMed

    Rai, Balwant; Foing, Bernard H; Kaur, Jasdeep

    2012-05-16

    The buoyancy of humans in exploring extreme space environments has been established during missions to the moon. Long duration missions like mission to Mars however, requires humans to adapt to systemic and complex environments beyond the human body's capacity. Astronauts will encounter both physiological and psychological extremes during this trip. Very few studies are conducted on effect of long duration work and sleepiness on cognitive performance. So, this study was planned to find out effects of leadership responsibility, sleepiness and long duration working hours on cognitive performance. The 30 members (leadership: normal; 10:20) were selected from MDRS crews (Mars Desert Research Station, USA). Neurobehavioral test performance, self-ratings of fatigue and sleepiness, and salivary cortisol levels were evaluated during first day, mid and end day of mission. The leadership group did not show any signs of reduced test performance, even in elevated fatigue and sleepiness. The leadership group had faster reaction times on end of mission as compared to first and after 7 day of mission. Salivary cortisol levels were significantly higher in leadership group as compared to normal group. The results suggest that long duration work and sleepiness does not affect the cognitive performance of crew member. Further study is required while taking into account all factors and large sample size to prove this fact. PMID:22487731

  19. Working hours, sleep, salivary cortisol, fatigue and neuro-behavior during Mars analog mission: five crews study.

    PubMed

    Rai, Balwant; Foing, Bernard H; Kaur, Jasdeep

    2012-05-16

    The buoyancy of humans in exploring extreme space environments has been established during missions to the moon. Long duration missions like mission to Mars however, requires humans to adapt to systemic and complex environments beyond the human body's capacity. Astronauts will encounter both physiological and psychological extremes during this trip. Very few studies are conducted on effect of long duration work and sleepiness on cognitive performance. So, this study was planned to find out effects of leadership responsibility, sleepiness and long duration working hours on cognitive performance. The 30 members (leadership: normal; 10:20) were selected from MDRS crews (Mars Desert Research Station, USA). Neurobehavioral test performance, self-ratings of fatigue and sleepiness, and salivary cortisol levels were evaluated during first day, mid and end day of mission. The leadership group did not show any signs of reduced test performance, even in elevated fatigue and sleepiness. The leadership group had faster reaction times on end of mission as compared to first and after 7 day of mission. Salivary cortisol levels were significantly higher in leadership group as compared to normal group. The results suggest that long duration work and sleepiness does not affect the cognitive performance of crew member. Further study is required while taking into account all factors and large sample size to prove this fact.

  20. The effect of staggering a biplane

    NASA Technical Reports Server (NTRS)

    Norton, F H

    1921-01-01

    This investigation was carried out by request of the United States Air Service at the Massachusetts Institute of Technology wind tunnel in 1918. As the data collected may be of general interest, they are published here by the National Advisory Committee for Aeronautics. The lift, drag, and center of pressure travel are determined for a biplane with a stagger varying from +100% to -100%. It is found that the efficiency and the maximum lift increase with positive stagger. With large positive staggers the center of pressure is far forward and has a very slight travel with changes in lift coefficient.

  1. Multimodal observational assessment of quality and productivity benefits from the implementation of wireless technology for out of hours working

    PubMed Central

    Blakey, John D; Guy, Debbie; Simpson, Carl; Fearn, Andrew; Cannaby, Sharon; Wilson, Petra

    2012-01-01

    Objectives The authors investigated if a wireless system of call handling and task management for out of hours care could replace a standard pager-based system and improve markers of efficiency, patient safety and staff satisfaction. Design Prospective assessment using both quantitative and qualitative methods, including interviews with staff, a standard satisfaction questionnaire, independent observation, data extraction from work logs and incident reporting systems and analysis of hospital committee reports. Setting A large teaching hospital in the UK. Participants Hospital at night co-ordinators, clinical support workers and junior doctors handling approximately 10 000 tasks requested out of hours per month. Outcome measures Length of hospital stay, incidents reported, co-ordinator call logging activity, user satisfaction questionnaire, staff interviews. Results Users were more satisfied with the new system (satisfaction score 62/90 vs 82/90, p=0.0080). With the new system over 70 h/week of co-ordinator time was released, and there were fewer untoward incidents related to handover and medical response (OR=0.30, p=0.02). Broad clinical measures (cardiac arrest calls for peri-arrest situations and length of hospital stay) improved significantly in the areas covered by the new system. Conclusions The introduction of call handling software and mobile technology over a medical-grade wireless network improved staff satisfaction with the Hospital at Night system. Improvements in efficiency and information flow have been accompanied by a reduction in untoward incidents, length of stay and peri-arrest calls. PMID:22466035

  2. EFFECTS OF LONG-TIME COMMUTING AND LONG-HOUR WORKING ON LIFESTYLE AND MENTAL HEALTH AMONG SCHOOL TEACHERS IN TOKYO, JAPAN.

    PubMed

    Nomoto, Marino; Hara, Akiko; Kikuchi, Kimiyo

    2015-06-01

    The objective of this study was to investigate the effects of long-time commuting and long-hour working on lifestyle including sleeping, physical exercise, breakfast, smoking, alcohol intake and mental health. In this cross-sectional study, data were collected from 146 school teachers in Tokyo. The binary associations of commuting time and working hours with lifestyle, mental stress measured by the General Health Questionnaire (GHQ) and stress coping measured by the Sense of Coherence (SOC) scores were examined. The Chi-square test was used for statistical analyses. Our results indicated that the mean commuting time and working hours per week of the respondents were 42.1 (SD 22.5) minutes and 50.4 (SD 8.6) hours, respectively. Longer commuting time was significantly associated with shorter working hours (p = 0.023), less physical exercise (p < 0.001) and shorter sleeping hours (p = 0.001). Longer working hours were significantly associated with more frequent working on holidays (p = 0.001), higher SOC scores (p = 0.001) and more smoking (p = 0.028). The negative association between GHQ and SOC scores was also significant (p < 0.001). Our findings revealed that long-time commuters were more likely to sleep less, exercise less and work less long. Long-hour workers were more likely to commute shorter, work on holidays more frequently, smoke more and their stress coping potentials were higher. Some kinds of strategies are required to improve the healthy lifestyle for long-time com- muters or long-hour workers. Key words: stress; stress coping; general health questionnaire; sense of coherence PMID:27281916

  3. EFFECTS OF LONG-TIME COMMUTING AND LONG-HOUR WORKING ON LIFESTYLE AND MENTAL HEALTH AMONG SCHOOL TEACHERS IN TOKYO, JAPAN.

    PubMed

    Nomoto, Marino; Hara, Akiko; Kikuchi, Kimiyo

    2015-06-01

    The objective of this study was to investigate the effects of long-time commuting and long-hour working on lifestyle including sleeping, physical exercise, breakfast, smoking, alcohol intake and mental health. In this cross-sectional study, data were collected from 146 school teachers in Tokyo. The binary associations of commuting time and working hours with lifestyle, mental stress measured by the General Health Questionnaire (GHQ) and stress coping measured by the Sense of Coherence (SOC) scores were examined. The Chi-square test was used for statistical analyses. Our results indicated that the mean commuting time and working hours per week of the respondents were 42.1 (SD 22.5) minutes and 50.4 (SD 8.6) hours, respectively. Longer commuting time was significantly associated with shorter working hours (p = 0.023), less physical exercise (p < 0.001) and shorter sleeping hours (p = 0.001). Longer working hours were significantly associated with more frequent working on holidays (p = 0.001), higher SOC scores (p = 0.001) and more smoking (p = 0.028). The negative association between GHQ and SOC scores was also significant (p < 0.001). Our findings revealed that long-time commuters were more likely to sleep less, exercise less and work less long. Long-hour workers were more likely to commute shorter, work on holidays more frequently, smoke more and their stress coping potentials were higher. Some kinds of strategies are required to improve the healthy lifestyle for long-time com- muters or long-hour workers. Key words: stress; stress coping; general health questionnaire; sense of coherence

  4. Wages and Hours of Work of Nonsupervisory Employees in All Private Nonfarm Industries by Coverage Status Under the Fair Labor Standards Act.

    ERIC Educational Resources Information Center

    Employment Standards Administration (DOL), Washington, DC.

    At the request of the Employment Standards Administration, the Bureau of Labor Statistics conducted a nationwide survey of private nonfarm industries, designed to provide comprehensive frequency distributions of nonsupervisory employees by average straight-time hourly earnings and weekly hours of work by coverage status under the Fair Labor…

  5. Pseudoscalar flavor-singlets and staggered fermions

    NASA Astrophysics Data System (ADS)

    Gregory, Eric

    2006-12-01

    The Asqtad improved staggered fermion formalism has been a valuable tool in successfully cal- culating the non-singlet parts of the hadronic spectrum. We are engaged in a project to calculate the spectrum of the pseudoscalar singlet mesons with 2 + 1-flavor Asqtad staggered gauge con- figurations. Propagators of flavor-singlet states incorporate contributions from both disconnected and connected diagrams, and hence are sensitive to any differences in the actions governing the sea and valence fermions on the lattice. As such, they also present the possibility of a probe of the validity of the "fourth-root trick" in the staggered fermion formulation. We present an update on our progress toward measuring the η mass on 2 + 1-flavor Asqtad staggered gauge configura- tions, including a review of methods and preliminary results. We also show a strong correlation between Tr(γ5 ⊗ 1) and the topological charge in these configurations, as predicted by the index theorem.

  6. Effects of long work hours and poor sleep characteristics on workplace injury among full-time male employees of small- and medium-scale businesses.

    PubMed

    Nakata, Akinori

    2011-12-01

    The aim of this study was to investigate the effects of long work hours and poor sleep characteristics on workplace injury. A total of 1891 male employees, aged 18-79 years (mean 45 years), in 296 small- and medium-scale businesses in a suburb of Tokyo were surveyed by means of a self-administered questionnaire during August-December 2002. Work hours and sleep characteristics, including daily sleep hours, subjective sleep sufficiency, sleep quality and easiness to wake up in the morning, were evaluated. Information on workplace injury in the past 1-year period was self-reported. The risk of workplace injury associated with work hours and poor sleep was estimated using multivariate logistic regression with odds ratio (ORs) and 95% confidence intervals as measures of associations. Compared with those working 6-8 h day(-1) with good sleep characteristics, positive interactive effects for workplace injury were found between long work hours (>8-10 h day(-1) or >10 h day(-1) ) and short sleep duration (<6 h) [adjusted OR (aOR), 1.27-1.54], subjective insufficient sleep (aOR, 1.94-1.99), sleep poorly at night (aOR, 2.23-2.49) and difficulty waking up in the morning (aOR, 1.56-1.59). Long work hours (aOR, 1.31-1.48), subjective insufficient sleep (aOR, 1.49) and sleeping poorly at night (aOR, 1.72) were also independently associated with workplace injury. This study suggests that long work hours coupled with poor sleep characteristics are synergistically associated with increased risk of workplace injury. Greater attention should be paid to manage/treat poor sleep and reduce excessive work hours to improve safety at the workplace.

  7. 29 CFR 778.412 - Relationship between amount guaranteed and range of hours employee may be expected to work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... workweeks. In both Walling v. A. H. Belo Co., 316 U.S. 624 and Walling v. Halliburton Oil Well Cementing Co... 29 Labor 3 2010-07-01 2010-07-01 false Relationship between amount guaranteed and range of hours...) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT...

  8. Labor Market Work and Home Care's Unpaid Caregivers: A Systematic Review of Labor Force Participation Rates, Predictors of Labor Market Withdrawal, and Hours of Work

    PubMed Central

    Lilly, Meredith B; Laporte, Audrey; Coyte, Peter C

    2007-01-01

    As people continue to age and receive complex health care services at home, concern has arisen about the availability of family caregivers and their ability to combine employment with caregiving. This article evaluates the international research on unpaid caregivers and their labor market choices, highlighting three conclusions: first, caregivers in general are equally as likely to be in the labor force as noncaregivers; second, caregivers are more likely to work fewer hours in the labor market than noncaregivers, particularly if their caring commitments are heavy; and finally, only those heavily involved in caregiving are significantly more likely to withdraw from the labor market than noncaregivers. Policy recommendations are targeting greater access to formal care for “intensive” caregivers and developing workplace policies for employed caregivers. PMID:18070333

  9. Rooted staggered fermions: good, bad or ugly?

    NASA Astrophysics Data System (ADS)

    Sharpe, Stephen

    2006-12-01

    I give a status report on the validity of the so-called "fourth-root trick", i.e. the procedure of representing the determinant for a single fermion by the fourth root of the staggered fermion determinant. This has been used by the MILC collaboration to create a large ensemble of lattices using which many quantities of physical interest have been and are being calculated. It is also used extensively in studies of QCD thermodynamics. The main question is whether the theory so defined has the correct continuum limit. There has been significant recent progress towards answering this question. After recalling the issue, and putting it into a broader context of results from statistical mechanics, I critically review the new work. I also address the related issue of the impact of treating valence and sea quarks differently in rooted simulations, discuss whether rooted simulations at finite temperature and density are subject to additional concerns, and briefly update results for quark masses using the MILC configurations. An answer to the question in the title is proposed in the summary.

  10. Staggered chiral perturbation theory for heavy-light mesons

    SciTech Connect

    Aubin, C.; Bernard, C.

    2006-01-01

    We incorporate heavy-light mesons into staggered chiral perturbation theory (S{chi}PT), working to leading order in 1/m{sub Q}, where m{sub Q} is the heavy-quark mass. At first nontrivial order in the chiral expansion, staggered taste violations affect the chiral logarithms for heavy-light quantities only through the light-meson propagators in loops. There are also new analytic contributions coming from additional terms in the Lagrangian involving heavy-light and light mesons. Using this heavy-light S{chi}PT, we perform the one-loop calculation of the B (or D) meson leptonic decay constant in the partially quenched and full QCD cases. In our treatment, we assume the validity both of the 'fourth root trick' to reduce four staggered tastes to one, and of the S{chi}PT prescription to represent this trick by insertions of factors of 1/4 for each sea-quark loop.

  11. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false How many hours per week must an adult or minor... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  12. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 2 2013-10-01 2012-10-01 true How many hours per week must an adult or minor head... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  13. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 2 2012-10-01 2012-10-01 false How many hours per week must an adult or minor... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  14. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true How many hours per week must an adult or minor head... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  15. 45 CFR 286.90 - How many hours per week must an adult or minor head-of-household participate in work-related...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false How many hours per week must an adult or minor... must an adult or minor head-of-household participate in work-related activities to count in the numerator of the work participation rate? During the month, an adult or minor head-of-household...

  16. Staggered heavy baryon chiral perturbation theory

    SciTech Connect

    Bailey, Jon A.

    2008-03-01

    Although taste violations significantly affect the results of staggered calculations of pseudoscalar and heavy-light mesonic quantities, those entering staggered calculations of baryonic quantities have not been quantified. Here I develop staggered chiral perturbation theory in the light-quark baryon sector by mapping the Symanzik action into heavy baryon chiral perturbation theory. For 2+1 dynamical quark flavors, the masses of flavor-symmetric nucleons are calculated to third order in partially quenched and fully dynamical staggered chiral perturbation theory. To this order the expansion includes the leading chiral logarithms, which come from loops with virtual decuplet-like states, as well as terms of O(m{sub {pi}}{sup 3}), which come from loops with virtual octet-like states. Taste violations enter through the meson propagators in loops and tree-level terms of O(a{sup 2}). The pattern of taste symmetry breaking and the resulting degeneracies and mixings are discussed in detail. The resulting chiral forms are appropriate to lattice results obtained with operators already in use and could be used to study the restoration of taste symmetry in the continuum limit. I assume that the fourth root of the fermion determinant can be incorporated in staggered chiral perturbation theory using the replica method.

  17. Staggered heavy baryon chiral perturbation theory

    NASA Astrophysics Data System (ADS)

    Bailey, Jon A.

    2008-03-01

    Although taste violations significantly affect the results of staggered calculations of pseudoscalar and heavy-light mesonic quantities, those entering staggered calculations of baryonic quantities have not been quantified. Here I develop staggered chiral perturbation theory in the light-quark baryon sector by mapping the Symanzik action into heavy baryon chiral perturbation theory. For 2+1 dynamical quark flavors, the masses of flavor-symmetric nucleons are calculated to third order in partially quenched and fully dynamical staggered chiral perturbation theory. To this order the expansion includes the leading chiral logarithms, which come from loops with virtual decuplet-like states, as well as terms of O(mπ3), which come from loops with virtual octet-like states. Taste violations enter through the meson propagators in loops and tree-level terms of O(a2). The pattern of taste symmetry breaking and the resulting degeneracies and mixings are discussed in detail. The resulting chiral forms are appropriate to lattice results obtained with operators already in use and could be used to study the restoration of taste symmetry in the continuum limit. I assume that the fourth root of the fermion determinant can be incorporated in staggered chiral perturbation theory using the replica method.

  18. 29 CFR 5.15 - Limitations, variations, tolerances, and exemptions under the Contract Work Hours and Safety...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... injustice, or undue hardship, or to avoid serious impairment of the conduct of Government business. Any... in order to prevent injustice, undue hardship, or serious impairment of Government business: (1... hourly equivalent to the rate on which time-and-one-half overtime compensation may be computed and...

  19. Working Longer Makes Students Stronger? The Effects of Ninth Grade Classroom Hours on Ninth Grade Student Performance

    ERIC Educational Resources Information Center

    Jensen, Vibeke Myrup

    2013-01-01

    Background: Despite much discussion on the role of education policy on school and student performance, we know little about the effects of school spending at the margin on student cognitive achievement beyond the effects of class size. Purpose: The paper examines the effects of annual ninth grade classroom hours in literacy and maths on ninth…

  20. Occupational and public health considerations for work-hour limitations policy regarding public health workers during response to natural and human-caused disasters.

    PubMed

    Berkowitz, Murray R

    2012-01-01

    This article examines the occupational health considerations that might impact the health and wellbeing of public health workers during responses to natural (eg, floods and hurricanes) and human-caused (eg, terrorism, war, and shootings) disasters. There are a number of articles in the medical literature that argue the impact of how working long hours by house staff physicians, nurses, and first-responders may pose health and safety concerns regarding the patients being treated. The question examined here is how working long hours may pose health and/or safety concerns for the public health workers themselves, as well as to those in the communities they serve. The health problems related to sleep deprivation are reviewed. Current policies and legislations regarding work-hour limitations are examined. Policy implications are discussed. PMID:23140062

  1. Occupational and public health considerations for work-hour limitations policy regarding public health workers during response to natural and human-caused disasters.

    PubMed

    Berkowitz, Murray R

    2012-01-01

    This article examines the occupational health considerations that might impact the health and wellbeing of public health workers during responses to natural (eg, floods and hurricanes) and human-caused (eg, terrorism, war, and shootings) disasters. There are a number of articles in the medical literature that argue the impact of how working long hours by house staff physicians, nurses, and first-responders may pose health and safety concerns regarding the patients being treated. The question examined here is how working long hours may pose health and/or safety concerns for the public health workers themselves, as well as to those in the communities they serve. The health problems related to sleep deprivation are reviewed. Current policies and legislations regarding work-hour limitations are examined. Policy implications are discussed.

  2. Staggered Multiple-PRF Ultrafast Color Doppler.

    PubMed

    Posada, Daniel; Poree, Jonathan; Pellissier, Arnaud; Chayer, Boris; Tournoux, Francois; Cloutier, Guy; Garcia, Damien

    2016-06-01

    Color Doppler imaging is an established pulsed ultrasound technique to visualize blood flow non-invasively. High-frame-rate (ultrafast) color Doppler, by emissions of plane or circular wavefronts, allows severalfold increase in frame rates. Conventional and ultrafast color Doppler are both limited by the range-velocity dilemma, which may result in velocity folding (aliasing) for large depths and/or large velocities. We investigated multiple pulse-repetition-frequency (PRF) emissions arranged in a series of staggered intervals to remove aliasing in ultrafast color Doppler. Staggered PRF is an emission process where time delays between successive pulse transmissions change in an alternating way. We tested staggered dual- and triple-PRF ultrafast color Doppler, 1) in vitro in a spinning disc and a free jet flow, and 2) in vivo in a human left ventricle. The in vitro results showed that the Nyquist velocity could be extended to up to 6 times the conventional limit. We found coefficients of determination r(2) ≥ 0.98 between the de-aliased and ground-truth velocities. Consistent de-aliased Doppler images were also obtained in the human left heart. Our results demonstrate that staggered multiple-PRF ultrafast color Doppler is efficient for high-velocity high-frame-rate blood flow imaging. This is particularly relevant for new developments in ultrasound imaging relying on accurate velocity measurements.

  3. Scalar meson spectroscopy with lattice staggered fermions

    SciTech Connect

    Bernard, Claude; DeTar, Carleton; Fu Ziwen; Prelovsek, Sasa

    2007-11-01

    With sufficiently light up and down quarks the isovector (a{sub 0}) and isosinglet (f{sub 0}) scalar meson propagators are dominated at large distance by two-meson states. In the staggered-fermion formulation of lattice quantum chromodynamics, taste-symmetry breaking causes a proliferation of two-meson states that further complicates the analysis of these channels. Many of them are unphysical artifacts of the lattice approximation. They are expected to disappear in the continuum limit. The staggered-fermion fourth-root procedure has its purported counterpart in rooted staggered chiral perturbation theory (rS{chi}PT). Fortunately, the rooted theory provides a strict framework that permits the analysis of scalar meson correlators in terms of only a small number of low-energy couplings. Thus the analysis of the point-to-point scalar meson correlators in this context gives a useful consistency check of the fourth-root procedure and its proposed chiral realization. Through numerical simulation we have measured correlators for both the a{sub 0} and f{sub 0} channels in the 'Asqtad' improved staggered-fermion formulation in a lattice ensemble with lattice spacing a=0.12 fm. We analyze those correlators in the context of rS{chi}PT and obtain values of the low-energy chiral couplings that are reasonably consistent with previous determinations.

  4. Kaon decay amplitudes using staggered fermions

    SciTech Connect

    Sharpe, S.R.

    1986-12-01

    A status report is given of an attempt, using staggered fermions to calculate the real and imaginary parts of the amplitudes for K ..-->.. ..pi pi..,. Semi-quantitative results are found for the imaginary parts, and these suggest that epsilon' might be smaller than previously expected in the standard model.

  5. Development and preliminary validation of an index for indicating the risks of the design of working hours to health and wellbeing.

    PubMed

    Schomann, Carsten; Giebel, Ole; Nachreiner, Friedhelm

    2006-01-01

    BASS 4, a computer program for the design and evaluation of workings hours, is an example of an ergonomics-based software tool that can be used by safety practitioners at the shop floor with regard to legal, ergonomic, and economic criteria. Based on experiences with this computer program, a less sophisticated Working-Hours-Risk Index for assessing the quality of work schedules (including flexible work hours) to indicate risks to health and wellbeing has been developed to provide a quick and easy applicable tool for legally required risk assessments. The results of a validation study show that this risk index seems to be a promising indicator for predicting risks of health complaints and wellbeing. The purpose of the Risk Index is to simplify the evaluation process at the shop floor and provide some more general information about the quality of a work schedule that can be used for triggering preventive interventions. Such a risk index complies with practitioners' expectations and requests for easy, useful, and valid instruments.

  6. Staggered solution procedures for multibody dynamics simulation

    NASA Astrophysics Data System (ADS)

    Park, K. C.; Chiou, J. C.; Downer, J. D.

    1990-04-01

    The numerical solution procedure for multibody dynamics (MBD) systems is termed a staggered MBD solution procedure that solves the generalized coordinates in a separate module from that for the constraint force. This requires a reformulation of the constraint conditions so that the constraint forces can also be integrated in time. A major advantage of such a partitioned solution procedure is that additional analysis capabilities such as active controller and design optimization modules can be easily interfaced without embedding them into a monolithic program. After introducing the basic equations of motion for MBD system in the second section, Section 3 briefly reviews some constraint handling techniques and introduces the staggered stabilized technique for the solution of the constraint forces as independent variables. The numerical direct time integration of the equations of motion is described in Section 4. As accurate damping treatment is important for the dynamics of space structures, we have employed the central difference method and the mid-point form of the trapezoidal rule since they engender no numerical damping. This is in contrast to the current practice in dynamic simulations of ground vehicles by employing a set of backward difference formulas. First, the equations of motion are partitioned according to the translational and the rotational coordinates. This sets the stage for an efficient treatment of the rotational motions via the singularity-free Euler parameters. The resulting partitioned equations of motion are then integrated via a two-stage explicit stabilized algorithm for updating both the translational coordinates and angular velocities. Once the angular velocities are obtained, the angular orientations are updated via the mid-point implicit formula employing the Euler parameters. When the two algorithms, namely, the two-stage explicit algorithm for the generalized coordinates and the implicit staggered procedure for the constraint Lagrange

  7. Investigation of deformation mechanisms of staggered nanocomposites using molecular dynamics

    NASA Astrophysics Data System (ADS)

    Mathiazhagan, S.; Anup, S.

    2016-08-01

    Biological materials with nanostructure of regularly or stair-wise staggered arrangements of hard platelets reinforced in a soft protein matrix have superior mechanical properties. Applications of these nanostructures to ceramic matrix composites could enhance their toughness. Using molecular dynamics simulations, mechanical behaviour of the bio-inspired nanocomposites is studied. Regularly staggered model shows better flow behaviour compared to stair-wise staggered model due to the symmetrical crack propagation along the interface. Though higher stiffness and strength are obtained for stair-wise staggered models, rapid crack propagation reduces the toughness. Arresting this crack propagation could lead to superior mechanical properties in stair-wise staggered models.

  8. Fan Stagger Angle for Dirt Rejection

    NASA Technical Reports Server (NTRS)

    Gallagher, Edward J. (Inventor); Rose, Becky E. (Inventor); Brilliant, Lisa I. (Inventor)

    2015-01-01

    A gas turbine engine includes a spool, a turbine coupled to drive the spool, a propulsor coupled to be rotated about an axis by the turbine through the spool, and a gear assembly coupled between the propulsor and the spool such that rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extend from the hub. Each of the propulsor blades has a span between a root at the hub and a tip, and a chord between a leading edge and a trailing edge. The chord forms a stagger angle alpha with the axis, and the stagger angle alpha is less than 15 deg. at a position along the propulsor blade that is within an inboard 20% of the span.

  9. 29 CFR 790.5 - Effect of Portal-to-Portal Act on determination of hours worked.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... GENERAL STATEMENT AS TO THE EFFECT OF THE PORTAL-TO-PORTAL ACT OF 1947 ON THE FAIR LABOR STANDARDS ACT OF... wage and overtime compensation provisions of the Fair Labor Standards Act to activities of employees on... activity would be time worked within the meaning of the Fair......

  10. 29 CFR 790.5 - Effect of Portal-to-Portal Act on determination of hours worked.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... GENERAL STATEMENT AS TO THE EFFECT OF THE PORTAL-TO-PORTAL ACT OF 1947 ON THE FAIR LABOR STANDARDS ACT OF... wage and overtime compensation provisions of the Fair Labor Standards Act to activities of employees on... activity would be time worked within the meaning of the Fair......

  11. 29 CFR 790.5 - Effect of Portal-to-Portal Act on determination of hours worked.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... GENERAL STATEMENT AS TO THE EFFECT OF THE PORTAL-TO-PORTAL ACT OF 1947 ON THE FAIR LABOR STANDARDS ACT OF... wage and overtime compensation provisions of the Fair Labor Standards Act to activities of employees on... activity would be time worked within the meaning of the Fair......

  12. 29 CFR 790.5 - Effect of Portal-to-Portal Act on determination of hours worked.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... GENERAL STATEMENT AS TO THE EFFECT OF THE PORTAL-TO-PORTAL ACT OF 1947 ON THE FAIR LABOR STANDARDS ACT OF... wage and overtime compensation provisions of the Fair Labor Standards Act to activities of employees on... activity would be time worked within the meaning of the Fair......

  13. 29 CFR 790.5 - Effect of Portal-to-Portal Act on determination of hours worked.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... GENERAL STATEMENT AS TO THE EFFECT OF THE PORTAL-TO-PORTAL ACT OF 1947 ON THE FAIR LABOR STANDARDS ACT OF... wage and overtime compensation provisions of the Fair Labor Standards Act to activities of employees on... activity would be time worked within the meaning of the Fair......

  14. [Longer working hours of pharmacists in the ward resulted in lower medication-related errors--survey of national university hospitals in Japan].

    PubMed

    Matsubara, Kazuo; Toyama, Akira; Satoh, Hiroshi; Suzuki, Hiroshi; Awaya, Toshio; Tasaki, Yoshikazu; Yasuoka, Toshiaki; Horiuchi, Ryuya

    2011-04-01

    It is obvious that pharmacists play a critical role as risk managers in the healthcare system, especially in medication treatment. Hitherto, there is not a single multicenter-survey report describing the effectiveness of clinical pharmacists in preventing medical errors from occurring in the wards in Japan. Thus, we conducted a 1-month survey to elucidate the relationship between the number of errors and working hours of pharmacists in the ward, and verified whether the assignment of clinical pharmacists to the ward would prevent medical errors between October 1-31, 2009. Questionnaire items for the pharmacists at 42 national university hospitals and a medical institute included the total and the respective numbers of medication-related errors, beds and working hours of pharmacist in 2 internal medicine and 2 surgical departments in each hospital. Regardless of severity, errors were consecutively reported to the Medical Security and Safety Management Section in each hospital. The analysis of errors revealed that longer working hours of pharmacists in the ward resulted in less medication-related errors; this was especially significant in the internal medicine ward (where a variety of drugs were used) compared with the surgical ward. However, the nurse assignment mode (nurse/inpatients ratio: 1 : 7-10) did not influence the error frequency. The results of this survey strongly indicate that assignment of clinical pharmacists to the ward is critically essential in promoting medication safety and efficacy. PMID:21467804

  15. Relationship between Working Hours and Power of Attention, Memory, Fatigue, Depression and Self-Efficacy One Year after Diagnosis of Clinically Isolated Syndrome and Relapsing Remitting Multiple Sclerosis

    PubMed Central

    Jongen, Peter Joseph; Wesnes, Keith; van Geel, Björn; Pop, Paul; Schrijver, Hans; Visser, Leo H.; Gilhuis, H. Jacobus; Sinnige, Ludovicus G.; Brands, Augustina M.

    2014-01-01

    The role of cognitive domain dysfunction with respect to vocational changes in persons with Clinically Isolated Syndrome (CIS) and early Relapsing Remitting Multiple Sclerosis (eRRMS) is insufficiently known. We investigated thirty-three patients - 14 CIS, 19 eRRMS -, mean (standard deviation [SD]) time since diagnosis 13.5 (4.8) months and mean (SD) Expanded Disability Status Scale (EDSS) score 1.3 (1.1). Patients were assessed on the CDR System, a set of automated tests of cognitive function, which yielded scores for Power of Attention (ms), Continuity of Attention (#), Working Memory (SI), Episodic Memory (#) and Speed of Memory (ms). Work-related items and the confounding variables fatigue, depression, disease impact and self-efficacy, were assessed by self-report questionnaires. Patients had poorer Power of Attention compared to normative data (1187 [161.5] vs. 1070 [98.6]; P<0.0001) and slower Speed of Memory (4043 [830.6]) vs. 2937 [586.1]; P<0.0001). Power of Attention (Pearson r = −0.42; P<0.04), Working Memory (r = 0.42; P<0.04) and depression r = −0.41; P<0.05) correlated with number of days worked per week. Fatigue (r = −0.56; P<0.005), self-efficacy (r = 0.56; P<0.005) and disease impact (r = −0.46; P<0.05) correlated with number of hours worked per week. Persons who wished to work less had poorer Power of Attention (1247 vs. 1116 ms; P<0.02), those who wished to change job had poorer Episodic Memory (1.35 vs. 1.57; p<0.03). People who reduced working hours within 12 months after diagnosis had higher fatigue and disease impact, and lower self-efficacy. The findings of this pilot study indicate that one year after the diagnosis of CIS and RRMS Power of Attention and Speed of Memory are reduced, that Power of Attention and Memory are associated with a capability of working less hours, and that fatigue, depression and disease impact may negatively, and self-efficacy positively affect working hours. PMID:24787714

  16. Effects of cold acclimation on the energetic metabolism of the staggerer mutant mouse.

    PubMed

    Bertin, R; Guastavino, J M; Portet, R

    1990-02-01

    Staggerer mutant mice are lean despite their hyperphagia. Brown adipose tissue activity may be implicated in this phenomenon. The aim of this work is to determine the energetic metabolism and to detail some characteristics of the brown adipose tissue of Staggerer mutant mice born and reared either at 28 degrees C (within the thermoneutral zone) or 22 degrees C (cold temperature) compared to nonmutant control mice. In mutant mice reared at thermoneutrality the resting metabolism was found to be higher than that of controls, and further the activity of the brown adipose tissue increased as indicated in relative mass, composition and cytochrome oxydase activity. A stimulatory effect of cold exposure was observed in both mutant and nonmutant mice. It is suggested that Staggerer mice may provide a good model for the study of the cold-induced or diet-induced mechanisms of brown fat stimulation.

  17. Topological index theorem on the lattice through the spectral flow of staggered fermions

    NASA Astrophysics Data System (ADS)

    Azcoiti, V.; Follana, E.; Vaquero, A.; Di Carlo, G.

    2015-05-01

    We investigate numerically the spectral flow introduced by Adams for the staggered Dirac operator on realistic (quenched) gauge configurations. We obtain clear numerical evidence that the definition works as expected: there is a clear separation between crossings near and far away from the origin, and the topological charge defined through the crossings near the origin agrees, for most configurations, with the one defined through the near-zero modes of large taste-singlet chirality of the staggered Dirac operator. The crossings are much closer to the origin if we improve the Dirac operator used in the definition, and they move towards the origin as we decrease the lattice spacing.

  18. Does Simulator-Based Clinical Performance Correlate with Actual Hospital Behavior? The Effect of Extended Work Hours on Patient Care Provided by Medical Interns

    PubMed Central

    Gordon, James A.; Alexander, Erik K.; Lockley, Steven W.; Flynn-Evans, Erin; Venkatan, Suresh K.; Landrigan, Christopher P.; Czeisler, Charles A.

    2013-01-01

    Purpose The correlation between simulator-based medical performance and real-world behavior remains unclear. The authors conducted this study to explore whether the effects of extended work hours on clinical performance, as reported in prior hospital-based studies, could be observed in a simulator-based testing environment. Method Intern volunteers reported to the simulator laboratory in a rested state and again in a sleep-deprived state (after a traditional 24–30 hour overnight shift [n=17]). A subset also presented after a shortened overnight shift (maximum of 16 scheduled hours [n=8]). During each laboratory visit, participants managed two critically ill patients. An on-site physician scored each case, as did a blinded rater later watching videotapes of the performances (score=1 [worst] to 8 [best]; average of both cases = session score). Results Among all participants, the average simulator session score was 6.0 (95% CI: 5.6–6.4) in the rested state, and declined to 5.0 (95% CI: 4.6–5.4) after the traditional overnight shift (P<0.001). Among those who completed the shortened overnight shift, the average post-shift simulator session score was 5.8 (95% CI: 5.0–6.6) compared to 4.3 [95%CI: 3.8–4.9]) after a traditional extended shift (P<0.001). Conclusions In a clinical simulation test, medical interns performed significantly better after working a shortened overnight shift compared to a traditional extended shift. These findings are consistent with real-time hospital studies using the same shift schedule. Such an independent correlation not only confirms the detrimental impact of extended work hours on medical performance, but also supports the validity of simulation as a clinical performance assessment tool. PMID:20881679

  19. Enhancement of Radiative Efficiency with Staggered InGaN Quantum Well Light Emitting Diodes

    SciTech Connect

    Tansu, Nelson; Dierolf, Volkmar; Huang, Gensheng; Penn, Samson; Zhao, Hongping; Liu, Guangyu; Li, Xiaohang; Poplawsky, Jonathan

    2011-07-14

    The technology on the large overlap InGaN QWs developed in this program is currently implemented in commercial technology in enhancing the internal quantum efficiency in major LED industry in US and Asia. The scientific finding from this work supported by the DOE enabled the implementation of this step-like staggered quantum well in the commercial LEDs.

  20. Reductions in transformer losses achieved by staggering lamination layers

    NASA Astrophysics Data System (ADS)

    Albir, R. S.; Moses, A. J.

    1989-05-01

    The total loss of identical 3-phase, 3-limb, mitred and staggered cores assembled from 0.3 mm thick, conventional high permeability and laser scribed grain oriented silicon iron have been compared. The croes built from conventional material produced the best improvements when staggered and these were chosen to carry out further investigation to examine the effect of the stacking number and the T-joint design on the power loss of the cores. The power loss generally increased as the stagger length was increased, but an optimum stagger length range was determined at which the power loss was lowest. The percentage improvement in the power loss due to the introduction of the staggered technique is dependent upon the orientation of the material and the T-joint design. The best loss reduction compared to a mitred core of the same rating was around 5% using a core assembled from conventional material.

  1. Power module assemblies with staggered coolant channels

    DOEpatents

    Herron, Nicholas Hayden; Mann, Brooks S; Korich, Mark D

    2013-07-16

    A manifold is provided for supporting a power module assembly with a plurality of power modules. The manifold includes a first manifold section. The first face of the first manifold section is configured to receive the first power module, and the second face of the first manifold section defines a first cavity with a first baseplate thermally coupled to the first power module. The first face of the second manifold section is configured to receive the second power module, and the second face of the second manifold section defines a second cavity with a second baseplate thermally coupled to the second power module. The second face of the first manifold section and the second face of the second manifold section are coupled together such that the first cavity and the second cavity form a coolant channel. The first cavity is at least partially staggered with respect to second cavity.

  2. Penguin diagrams for improved staggered fermions

    SciTech Connect

    Lee, Weonjong

    2005-01-01

    We calculate, at the one-loop level, penguin diagrams for improved staggered fermion operators constructed using various fat links. The main result is that diagonal mixing coefficients with penguin operators are identical between the unimproved operators and the improved operators using such fat links as Fat7, Fat7+Lepage, Fat7, HYP (I) and HYP (II). In addition, it turns out that the off-diagonal mixing vanishes for those constructed using fat links of Fat7, Fat7 and HYP (II). This is a consequence of the fact that the improvement by various fat links changes only the mixing with higher dimension operators and off-diagonal operators. The results of this paper, combined with those for current-current diagrams, provide complete matching at the one-loop level with all corrections of O(g{sup 2}) included.

  3. Thermal Protection System with Staggered Joints

    NASA Technical Reports Server (NTRS)

    Simon, Xavier D. (Inventor); Robinson, Michael J. (Inventor); Andrews, Thomas L. (Inventor)

    2014-01-01

    The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

  4. Breaking the Long Hours Culture.

    ERIC Educational Resources Information Center

    Kodz, J.; Kersley, B.; Strebler, M. T.; O'Regan, S.

    Case studies of 12 leading British employers were driven by employers' interest in issues related to working long hours in light of introduction of the Working Time Directive, a European Community initiative enacted into British law that sets limits on working hours per week. Data showed over one-fourth of full-time employees worked over 48 hours…

  5. Sex inequalities in physical and mental functioning of British, Finnish, and Japanese civil servants: role of job demand, control and work hours.

    PubMed

    Sekine, Michikazu; Tatsuse, Takashi; Kagamimori, Sadanobu; Chandola, Tarani; Cable, Noriko; Marmot, Michael; Martikainen, Pekka; Lallukka, Tea; Rahkonen, Ossi; Lahelma, Eero

    2011-08-01

    In general, women report more physical and mental symptoms than men. International comparisons of countries with different welfare state regimes may provide further understanding of the social determinants of sex inequalities in health. This study aims to evaluate (1) whether there are sex inequalities in health functioning as measured by the Short Form 36 (SF-36), and (2) whether work characteristics contribute to the sex inequalities in health among employees from Britain, Finland, and Japan, representing liberal, social democratic, and conservative welfare state regimes, respectively. The participants were 7340 (5122 men and 2218 women) British employees, 2297 (1638 men and 659 women) Japanese employees, and 8164 (1649 men and 6515 women) Finnish employees. All the participants were civil servants aged 40-60 years. We found that more women than men tended to have disadvantaged work characteristics (i.e. low employment grade, low job control, high job demands, and long work hours) but such sex differences were relatively smaller among employees from Finland, where more gender equal policies exist than Britain and Japan. The age-adjusted odds ratio (OR) of women for poor physical functioning was the largest for British women (OR = 2.08), followed by for Japanese women (OR = 1.72), and then for Finnish women (OR = 1.51). The age-adjusted OR of women for poor mental functioning was the largest for Japanese women (OR = 1.91), followed by for British women (OR = 1.45), and then for Finnish women (OR = 1.07). Thus, sex differences in physical and mental health was the smallest in the Finnish population. The larger the sex differences in work characteristics, the larger the sex differences in health and the reduction in the sex differences in health after adjustment for work characteristics. These results suggest that egalitarian and gender equal policies may contribute to smaller sex differences in health, through smaller differences in disadvantaged work

  6. Local and national trends in general surgery residents' operative experience: do work hour limitations negatively affect case volume in small community-based programs?

    PubMed

    Markelov, Alexey; Sakharpe, Aniket; Kohli, Harjeet; Livert, David

    2011-12-01

    The goals of this study were to analyze the impact of work hour restrictions on the operative case volume at a small community-based general surgery residency training program and compare changes with the national level. Annual national resident case log data from Accreditation Council for Graduate Medical Education (ACGME) website and case logs of graduating Easton Hospital residents (years 2002-2009) were used for analysis. Weighted average change in total number of cases in our institution was -1.20 (P = 0.52) vs 1.78 (P = 0.07) for the national program average with statistically significant difference on comparison (P = 0.027). We also found significant difference in case volume changes at the national level compared with our institution for the following ACGME defined subcategories: alimentary tract [8.19 (P < 0.01) vs -1.08 (P = 0.54)], abdomen [8.48 (P < 0.01) vs -6.29 (P < 0.01)], breast [1.91 (P = 0.89) vs -3.6 (P = 0.02)], and vascular [4.03 (P = 0.02) vs -3.98 (P = 0.01)]. Comparing the national trend to the community hospital we see that there is total increase in cases at the national level whereas there is a decrease in case volume at the community hospital. These trends can also be followed in ACGME defined subcategories which form the major case load for a general surgical training such as alimentary tract, abdominal, breast, and vascular procedures. We hypothesize that work hour restrictions have been favorable for the larger programs, as these programs were able to better integrate the night float system, restructure their call schedule, and implement institutional modifications which are too resource demanding for smaller training programs.

  7. Investigating the influences of two position (non-staggered and staggered) of wind turbine arrays to produce power in a wind farm

    NASA Astrophysics Data System (ADS)

    Ismail, Kamal, Samsul; Purnomo, Sarjiya

    2016-06-01

    This investigation was conducted to identify the influences of the two positions (non-staggered and staggered) of wind turbine arrays. Identification on down-scaled size wind turbine arrays was carried out in an open circuit, suction-type wind tunnel. Based on the results of the experiment, empirical relations for the centreline velocity deficit, tipline velocity deficit and wake radius are proposed. The non-staggered position results are larger power generated than that of the staggered position, this influenced by the trend deficit in velocity that makes wind turbine generated power difference between staggered position and non-stagger position. The area used non-staggered position larger than staggered position. Result staggered position has become one of the solutions to harness wind farms confined areas.

  8. The possibility for a short-period hybrid staggered undulator.

    SciTech Connect

    Sasaki, S.; Experimental Facilities Division

    2005-01-01

    A short-period hybrid-type staggered undulator is proposed. A proper combination of vanadium Permendur (VP) pole and NdFeB magnet provide approximately 40% larger peak field strength than a conventional staggered undulator. The peak field of a 15-mm-period hybrid staggered undulator exceeds 0.8 T at a gap of 6 mm. Also, by using dysprosium as a pole and PrFeB as a magnet at liquid nitrogen temperature (77K), even higher peak field ({approx} 0.94 T) can be achieved at the same gap.

  9. A survey-based cross-sectional study of doctors’ expectations and experiences of non-technical skills for Out of Hours work

    PubMed Central

    Brown, Michael; Shaw, Dominick; Sharples, Sarah; Jeune, Ivan Le; Blakey, John

    2015-01-01

    Objectives The skill set required for junior doctors to work efficiently and safely Out of Hours (OoH) in hospitals has not been established. This is despite the OoH period representing 75% of the year and it being the time of highest mortality. We set out to explore the expectations of medical students and experiences of junior doctors of the non-technical skills needed to work OoH. Design Survey-based cross-sectional study informed by focus groups. Setting Online survey with participants from five large teaching hospitals across the UK. Participants 300 Medical Students and Doctors Outcome measure Participants ranked the importance of non-technical skills, as identified by literature review and focus groups, needed for OoH care. Results The focus groups revealed a total of eight non-technical skills deemed to be important. In the survey ‘Task Prioritisation’ (mean rank 1.617) was consistently identified as the most important non-technical skill. Stage of training affected the ranking of skills, with significant differences for ‘Communication with Senior Doctors’, ‘Dealing with Clinical Isolation’, ‘Task Prioritisation’ and ‘Communication with Patients’. Importantly, there was a significant discrepancy between the medical student expectations and experiences of doctors undertaking work. Conclusions Our findings suggest that medical staff particularly value task prioritisation skills; however, these are not routinely taught in medical schools. The discrepancy between expectations of students and experience of doctors reinforces the idea that there is a gap in training. Doctors of different grades place different importance on specific non-technical skills with implications for postgraduate training. There is a pressing need for medical schools and deaneries to review non-technical training to include more than communication skills. PMID:25687899

  10. Optimal Designs of Staggered Dean Vortex Micromixers

    PubMed Central

    Chen, Jyh Jian; Chen, Chun Huei; Shie, Shian Ruei

    2011-01-01

    A novel parallel laminar micromixer with a two-dimensional staggered Dean Vortex micromixer is optimized and fabricated in our study. Dean vortices induced by centrifugal forces in curved rectangular channels cause fluids to produce secondary flows. The split-and-recombination (SAR) structures of the flow channels and the impinging effects result in the reduction of the diffusion distance of two fluids. Three different designs of a curved channel micromixer are introduced to evaluate the mixing performance of the designed micromixer. Mixing performances are demonstrated by means of a pH indicator using an optical microscope and fluorescent particles via a confocal microscope at different flow rates corresponding to Reynolds numbers (Re) ranging from 0.5 to 50. The comparison between the experimental data and numerical results shows a very reasonable agreement. At a Re of 50, the mixing length at the sixth segment, corresponding to the downstream distance of 21.0 mm, can be achieved in a distance 4 times shorter than when the Re equals 1. An optimization of this micromixer is performed with two geometric parameters. These are the angle between the lines from the center to two intersections of two consecutive curved channels, θ, and the angle between two lines of the centers of three consecutive curved channels, ϕ. It can be found that the maximal mixing index is related to the maximal value of the sum of θ and ϕ, which is equal to 139.82°. PMID:21747691

  11. Non-perturbative Renormalization with Staggered Fermions

    NASA Astrophysics Data System (ADS)

    Lytle, Andrew

    Lattice studies of Standard Model phenomenology frequently require knowledge of matching factors, or "Z-factors," that convert lattice operators defined at the lattice scale to operators in a continuum scheme at a scale mu. We make the first non-perturbative determinations of Z-factors for improved, fully dynamical staggered fermions. We compute the mass renormalization factor Zm for the Asqtad action, which is the action used by the MILC collaboration[1]. We find the strange quark mass to be mMSs (2 GeV) = 103(3) MeV; significantly larger than the result obtained using the perturbative Z-factor[2]. We compute all 256 bilinear Z-factors for the HYP-smeared action, which provides a laboratory for comparison to the results of one-loop perturbation theory[3]. Our results indicate broad agreement for ratios of Z-factors, at the few percent level, while the Z-factors themselves differ at around the ten percent level. The bilinear calculations are a stepping stone towards computation of the four-Fermi Z-factors relevant for an ongoing precision calculation of BK[4, 5, 6, 7], the knowledge of which is used to constrain the CKM matrix. Uncertainty in the required matching factors constitutes the dominant source of error.

  12. Rail coal transportation under the Staggers Act

    SciTech Connect

    Carpenter, A.R.

    1984-01-01

    The Stagger's Act of 1980 offered railroads the opportunity to accelerate growth along with the coal industry in efforts to increase market for both the product (coal) and the service provided. It provides for cost recovery indexing allowing railroads to stay abreast of inflation and flexibility in setting and changing rates. It also allows railroads to enter directly into contract agreements with shippers. Railroads have used extreme caution in implementing these liberties so that the coal industry would not be severely impacted by these changes. They could have raised rates by as much as 52.3% under the new guidelines, but only raised them by 31.6% in the Eastern market and by 21.3% for export coal. The president of CSX Railroads stresses the symbiotic relationship existing between railroads and the coal industry. He suggests that separate sectors of the coal industry stop pointing fingers at one another and join hands to solve coal's competitive problems in the overseas export market. He calls for the formation of a blue-ribbon panel representing all of the parties with a stake in coal to implement such a cooperative effort. (DMC)

  13. Efficiency and optimal allocation in the staggered entry design

    USGS Publications Warehouse

    Link, W.A.

    1993-01-01

    The staggered entry design for survival analysis specifies that r left-truncated samples are to be used in estimation of a population survival function. The ith sample is taken at time Bi, from the subpopulation of individuals having survival time exceeding Bi. This paper investigates the performance of the staggered entry design relative to the usual design in which all samples have a common time origin. The staggered entry design is shown to be an attractive alternative, even when not necessitated by logistical constraints. The staggered entry design allows for increased precision in estimation of the right tail of the survival function, especially when some of the data may be censored. A trade-off between the range of values for which the increased precision occurs and the magnitude of the increased precision is demonstrated.

  14. Use of DAC-Hours for Radiation Work Permit Suspension Guides and Validation of Respiratory Equipment Selection at the Savannah River Site

    SciTech Connect

    Hadlock, D.J.

    2003-10-30

    Historically, the Savannah River Site, like many Department of Energy sites, has used some multiple of the expected Derived Air Concentration (DAC) of a radionuclide as a suspension guide for Radiological Work Permits (RWP) or validation of selected respiratory protection equipment. The term DAC expresses the concentration of a radionuclide in air, typically in mCi/cc. Even though the term DAC is derived from an intake of radioactivity (Annual Limit on Intake) that would result in defined estimated dose to a worker, knowing only the DAC value does not allow a worker's potential dose to be determined. Recently, the Savannah Rive Site has converted to the use of DAC-hours for RWP suspension guides and respiratory equipment validation. The term DAC-hr takes into account not only the concentration of the radionuclide in air (DAC) but also the time the individual was exposed allowing an estimate of a worker's dose to be determined. The conversion to DAC-hrs resulted in four benefits to the radiation protection program without increasing the risk to workers; (1) consistency with the constant air monitor (CAM) alarm setpoint protocol; (2) consistency with Internal Dosimetry terminology; (3) an a priori determination of the potential risk to a worker; and (4) reduced complexity/error in field calculations. This paper outlines the justification for the conversion to DAC-hrs, the protocols used for field and count room calculations, and the implementation process utilized at the Savannah River Site

  15. A staggered-grid convolutional differentiator for elastic wave modelling

    NASA Astrophysics Data System (ADS)

    Sun, Weijia; Zhou, Binzhong; Fu, Li-Yun

    2015-11-01

    The computation of derivatives in governing partial differential equations is one of the most investigated subjects in the numerical simulation of physical wave propagation. An analytical staggered-grid convolutional differentiator (CD) for first-order velocity-stress elastic wave equations is derived in this paper by inverse Fourier transformation of the band-limited spectrum of a first derivative operator. A taper window function is used to truncate the infinite staggered-grid CD stencil. The truncated CD operator is almost as accurate as the analytical solution, and as efficient as the finite-difference (FD) method. The selection of window functions will influence the accuracy of the CD operator in wave simulation. We search for the optimal Gaussian windows for different order CDs by minimizing the spectral error of the derivative and comparing the windows with the normal Hanning window function for tapering the CD operators. It is found that the optimal Gaussian window appears to be similar to the Hanning window function for tapering the same CD operator. We investigate the accuracy of the windowed CD operator and the staggered-grid FD method with different orders. Compared to the conventional staggered-grid FD method, a short staggered-grid CD operator achieves an accuracy equivalent to that of a long FD operator, with lower computational costs. For example, an 8th order staggered-grid CD operator can achieve the same accuracy of a 16th order staggered-grid FD algorithm but with half of the computational resources and time required. Numerical examples from a homogeneous model and a crustal waveguide model are used to illustrate the superiority of the CD operators over the conventional staggered-grid FD operators for the simulation of wave propagations.

  16. Topological susceptibility in staggered fermion chiral perturbation theory

    SciTech Connect

    Billeter, Brian; DeTar, Carleton; Osborn, James

    2004-10-01

    The topological susceptibility of the vacuum in quantum chromodynamics has been simulated numerically using the Asqtad improved staggered fermion formalism. At nonzero lattice spacing, the residual fermion doublers (fermion tastes) in the staggered fermion formalism give contributions to the susceptibility that deviate from conventional continuum chiral perturbation theory. In this brief report, we estimate the taste-breaking artifact and compare it with results of recent simulations, finding that it accounts for roughly half of the scaling violation.

  17. Blood Pressure, Sleep Quality and Fatigue in Shift Working Police Officers: Effects of a Twelve Hour Roster System on Cardiovascular and Sleep Health

    PubMed Central

    Elliott, Jaymen L.; Lal, Sara

    2016-01-01

    Background: Police officers have been reported to exhibit a high incidence of pathologies, which present prematurely in an otherwise healthy population. Shift work has also been associated with an increased risk of cardiovascular and sleep disorders, attributable to its propensity for circadian rhythm dysfunction. However, contention exists as to whether shift work has a direct effect upon blood pressure (BP) regulation. Methods: This cross-sectional study sought to determine changes in BP and associations with the overall sleep quality and fatigue in 206 general duties police officers (n = 140 males) of the New South Wales Police Force in Australia. The subjects’ BP was assessed before and after their twelve hour shift, during which time they also completed the Lifestyle Appraisal Questionnaire, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale and Fatigue Severity Scale (FSS). Results: Poor sleep quality (PSQI) and fatigue severity (FSS) were found to predominate in the sample (69% and 51% respectively). Although there was no change in BP for male participants, female officers’ systolic blood pressure (SBP) was found to increase significantly across the shift (p < 0.001), but with no change found in females’ diastolic blood pressure (DBP). Finally, higher pre and post-shift SBP (r = −0.26, p = 0.001; r = −0.25, p = 0.001, respectively) and DBP (r = −0.26, p = 0.001; r = −0.26, p = 0.001, respectively) were significantly correlated with lower FSS scores after accounting for age, waist-hip ratio and lifestyle risk factors. Conclusions: Based on these preliminary findings, there was a significant increase in SBP of female police officers after shift work, while BP and fatigue levels in all police officers were strongly related. Moreover, the predominating poor sleep quality and impact of fatigue in this sample remain a concern. Further research is required to ensure the physiological welfare of police officers, while strategies must be

  18. Effective field theories for QCD with rooted staggered fermions

    SciTech Connect

    Bernard, Claude; Golterman, Maarten; Shamir, Yigal

    2008-04-01

    Even highly improved variants of lattice QCD with staggered fermions show significant violations of taste symmetry at currently accessible lattice spacings. In addition, the 'rooting trick' is used in order to simulate with the correct number of light sea quarks, and this makes the lattice theory nonlocal, even though there is good reason to believe that the continuum limit is in the correct universality class. In order to understand scaling violations, it is thus necessary to extend the construction of the Symanzik effective theory to include rooted staggered fermions. We show how this can be done, starting from a generalization of the renormalization-group approach to rooted staggered fermions recently developed by one of us. We then explain how the chiral effective theory follows from the Symanzik action, and show that it leads to 'rooted' staggered chiral perturbation theory as the correct chiral theory for QCD with rooted staggered fermions. We thus establish a direct link between the renormalization-group based arguments for the correctness of the continuum limit and the success of rooted staggered chiral perturbation theory in fitting numerical results obtained with the rooting trick. In order to develop our argument, we need to assume the existence of a standard partially-quenched chiral effective theory for any local partially-quenched theory. Other technical, but standard, assumptions are also required.

  19. On preservation of symmetry in r-z staggered Lagrangian schemes

    NASA Astrophysics Data System (ADS)

    Váchal, Pavel; Wendroff, Burton

    2016-02-01

    In the focus of this work are symmetry preservation, conservation of energy and volume, and other important properties of staggered Lagrangian hydrodynamic schemes in cylindrical (r-z) geometry. It is well known that on quadrilateral cells in r-z, preservation of spherical symmetry, perfect satisfaction of the Geometrical Conservation Law (GCL), and total energy conservation are incompatible even on conforming grids. This paper suggests a novel staggered grid approach that preserves symmetry, conserves total energy by construction and tries to do its best by diminishing the GCL error to the order of entropy error. In particular, the forces from an existing volume consistent scheme are corrected so that spherical symmetry is preserved. The incorporation of subcell pressure mechanism to reduce spurious grid deformations is described and the relation of the new scheme to popular area-weighted and control volume approaches studied.

  20. A high-order staggered finite-element vertical discretization for non-hydrostatic atmospheric models

    DOE PAGES

    Guerra, Jorge E.; Ullrich, Paul A.

    2016-06-01

    Atmospheric modeling systems require economical methods to solve the non-hydrostatic Euler equations. Two major differences between hydrostatic models and a full non-hydrostatic description lies in the vertical velocity tendency and numerical stiffness associated with sound waves. In this work we introduce a new arbitrary-order vertical discretization entitled the staggered nodal finite-element method (SNFEM). Our method uses a generalized discrete derivative that consistently combines the discontinuous Galerkin and spectral element methods on a staggered grid. Our combined method leverages the accurate wave propagation and conservation properties of spectral elements with staggered methods that eliminate stationary (2Δx) modes. Furthermore, high-order accuracy alsomore » eliminates the need for a reference state to maintain hydrostatic balance. In this work we demonstrate the use of high vertical order as a means of improving simulation quality at relatively coarse resolution. We choose a test case suite that spans the range of atmospheric flows from predominantly hydrostatic to nonlinear in the large-eddy regime. Our results show that there is a distinct benefit in using the high-order vertical coordinate at low resolutions with the same robust properties as the low-order alternative.« less

  1. A high-order staggered finite-element vertical discretization for non-hydrostatic atmospheric models

    NASA Astrophysics Data System (ADS)

    Guerra, Jorge E.; Ullrich, Paul A.

    2016-06-01

    Atmospheric modeling systems require economical methods to solve the non-hydrostatic Euler equations. Two major differences between hydrostatic models and a full non-hydrostatic description lies in the vertical velocity tendency and numerical stiffness associated with sound waves. In this work we introduce a new arbitrary-order vertical discretization entitled the staggered nodal finite-element method (SNFEM). Our method uses a generalized discrete derivative that consistently combines the discontinuous Galerkin and spectral element methods on a staggered grid. Our combined method leverages the accurate wave propagation and conservation properties of spectral elements with staggered methods that eliminate stationary (2Δx) modes. Furthermore, high-order accuracy also eliminates the need for a reference state to maintain hydrostatic balance. In this work we demonstrate the use of high vertical order as a means of improving simulation quality at relatively coarse resolution. We choose a test case suite that spans the range of atmospheric flows from predominantly hydrostatic to nonlinear in the large-eddy regime. Our results show that there is a distinct benefit in using the high-order vertical coordinate at low resolutions with the same robust properties as the low-order alternative.

  2. Clinical practice patterns among native and immigrant doctors doing out-of-hours work in Norway: a registry-based observational study

    PubMed Central

    Hunskaar, Steinar; Diaz, Esperanza

    2012-01-01

    Objectives To evaluate whether immigrant and native Norwegian doctors differ in their practice patterns. Design Observational study. Setting Out-of-hours (OOH) emergency primary healthcare in Norway, 2008. Participants All primary care physicians doing OOH work, altogether 4165 physicians. Main outcome measures Number of patient contacts per doctor. Use of laboratory tests, minor surgery, sickness certification and length of consultations. Use of diagnoses related to psychiatric and sexual health. Choice of management strategy with psychiatric patients (psychotherapy or hospitalisation). Results 21.4% of the physicians were immigrants, and they had 30.6% of the patient contacts. Immigrant doctors from Asia, Africa and Latin America had most patient contacts, 633 (95% CI 549 to 716), while native Norwegian doctors had 306 (95% CI 288 to 325). In multivariate analyses, immigrant physicians did not differ significantly from native Norwegians regarding use of laboratory tests, minor surgery or length of consultations, but immigrant doctors wrote more sickness certificates, OR 1.75 (95% CI 1.24 to 2.47) for immigrant doctors from Europe, North America and Oceania versus native Norwegian doctors and OR 1.56 (95% CI 1.15 to 2.11) for immigrant doctors from Asia, Africa and Latin America versus native Norwegians. Immigrant physicians from Europe, North America and Oceania used more diagnoses related to pregnancy, family planning and female genitals, OR 1.55 (95% CI 1.11 to 2.16), versus native Norwegian physicians. Immigrant doctors from Asia, Africa and Latin America used less psychiatric diagnoses, OR 0.71 (95% CI 0.53 to 0.95), versus native Norwegian doctors but did not differ significantly in their management of recognised psychiatric illness. Conclusions Immigrant doctors make an important contribution to OOH emergency primary healthcare in Norway. The authors found only modest evidence that their clinical practice patterns are different from that of native Norwegian

  3. Staggered chiral perturbation theory and the fourth-root trick

    NASA Astrophysics Data System (ADS)

    Bernard, C.

    2006-06-01

    Staggered chiral perturbation theory (SχPT) takes into account the “fourth-root trick” for reducing unwanted (taste) degrees of freedom with staggered quarks by multiplying the contribution of each sea quark loop by a factor of 1/4. In the special case of four staggered fields (four flavors, nF=4), I show here that certain assumptions about analyticity and phase structure imply the validity of this procedure for representing the rooting trick in the chiral sector. I start from the observation that, when the four flavors are degenerate, the fourth root simply reduces nF=4 to nF=1. One can then treat nondegenerate quark masses by expanding around the degenerate limit. With additional assumptions on decoupling, the result can be extended to the more interesting cases of nF=3, 2, or 1. An apparent paradox associated with the one-flavor case is resolved. Coupled with some expected features of unrooted staggered quarks in the continuum limit, in particular, the restoration of taste symmetry, SχPT then implies that the fourth-root trick induces no problems (for example, a violation of unitarity that persists in the continuum limit) in the lowest energy sector of staggered lattice QCD. It also says that the theory with staggered valence quarks and rooted staggered sea quarks behaves like a simple, partially-quenched theory, not like a mixed theory in which sea and valence quarks have different lattice actions. In most cases, the assumptions made in this paper are not only sufficient but also necessary for the validity of SχPT, so that a variety of possible new routes for testing this validity are opened.

  4. Staggered chiral perturbation theory and the fourth-root trick

    SciTech Connect

    Bernard, C.

    2006-06-01

    Staggered chiral perturbation theory (S{chi}PT) takes into account the 'fourth-root trick' for reducing unwanted (taste) degrees of freedom with staggered quarks by multiplying the contribution of each sea quark loop by a factor of 1/4. In the special case of four staggered fields (four flavors, n{sub F}=4), I show here that certain assumptions about analyticity and phase structure imply the validity of this procedure for representing the rooting trick in the chiral sector. I start from the observation that, when the four flavors are degenerate, the fourth root simply reduces n{sub F}=4 to n{sub F}=1. One can then treat nondegenerate quark masses by expanding around the degenerate limit. With additional assumptions on decoupling, the result can be extended to the more interesting cases of n{sub F}=3, 2, or 1. An apparent paradox associated with the one-flavor case is resolved. Coupled with some expected features of unrooted staggered quarks in the continuum limit, in particular, the restoration of taste symmetry, S{chi}PT then implies that the fourth-root trick induces no problems (for example, a violation of unitarity that persists in the continuum limit) in the lowest energy sector of staggered lattice QCD. It also says that the theory with staggered valence quarks and rooted staggered sea quarks behaves like a simple, partially-quenched theory, not like a mixed theory in which sea and valence quarks have different lattice actions. In most cases, the assumptions made in this paper are not only sufficient but also necessary for the validity of S{chi}PT, so that a variety of possible new routes for testing this validity are opened.

  5. Entropy Stable Staggered Grid Spectral Collocation for the Burgers' and Compressible Navier-Stokes Equations

    NASA Technical Reports Server (NTRS)

    Carpenter, Mark H.; Parsani, Matteo; Fisher, Travis C.; Nielsen, Eric J.

    2015-01-01

    Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for Burgers' and the compressible Navier-Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [1, 2], extends the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to a combination of tensor product Legendre-Gauss (LG) and LGL points. The new semi-discrete operators discretely conserve mass, momentum, energy and satisfy a mathematical entropy inequality for both Burgers' and the compressible Navier-Stokes equations in three spatial dimensions. They are valid for smooth as well as discontinuous flows. The staggered LG and conventional LGL point formulations are compared on several challenging test problems. The staggered LG operators are significantly more accurate, although more costly to implement. The LG and LGL operators exhibit similar robustness, as is demonstrated using test problems known to be problematic for operators that lack a nonlinearly stability proof for the compressible Navier-Stokes equations (e.g., discontinuous Galerkin, spectral difference, or flux reconstruction operators).

  6. Artificial staggered magnetic field for ultracold atoms in optical lattices

    SciTech Connect

    Lim, Lih-King; Smith, C. Morais; Hemmerich, Andreas

    2010-02-15

    A time-dependent optical lattice with staggered particle current in the tight-binding regime was considered that can be described by a time-independent effective lattice model with an artificial staggered magnetic field. The low-energy description of a single-component fermion in this lattice at half-filling is provided by two copies of ideal two-dimensional massless Dirac fermions. The Dirac cones are generally anisotropic and can be tuned by the external staggered flux {phi}. For bosons, the staggered flux modifies the single-particle spectrum such that in the weak coupling limit, depending on the flux {phi}, distinct superfluid phases are realized. Their properties are discussed, the nature of the phase transitions between them is established, and Bogoliubov theory is used to determine their excitation spectra. Then the generalized superfluid-Mott-insulator transition is studied in the presence of the staggered flux and the complete phase diagram is established. Finally, the momentum distribution of the distinct superfluid phases is obtained, which provides a clear experimental signature of each phase in ballistic expansion experiments.

  7. 29 CFR 794.141 - Workweeks when hours worked do not exceed 12 in any day or 56 in the week; compensation...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... minimum wage.” (H. Rept. No. 1366, pp. 12-13, 43, and S. Rept. No. 1487, p. 32, 89th Cong., second sess... Standards Amendments of 1966 is $1.60 an hour. Under section 7(b)(3) an employee of a wholesale or bulk... defined in the Act or because the enterprise coverage provisions in effect prior to the 1966...

  8. 29 CFR 570.35 - Hours of work and conditions of employment permitted for minors 14 and 15 years of age.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... minors 14 and 15 years of age. 570.35 Section 570.35 Labor Regulations Relating to Labor (Continued) WAGE... and conditions of employment permitted for minors 14 and 15 years of age. (a) Hours standards. Except... provided, for any youth 14 or 15 years of age who: (i) Has graduated from high school; (ii) Has...

  9. 29 CFR 570.35 - Hours of work and conditions of employment permitted for minors 14 and 15 years of age.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... minors 14 and 15 years of age. 570.35 Section 570.35 Labor Regulations Relating to Labor (Continued) WAGE... and conditions of employment permitted for minors 14 and 15 years of age. (a) Hours standards. Except... provided, for any youth 14 or 15 years of age who: (i) Has graduated from high school; (ii) Has...

  10. 29 CFR 570.35 - Hours of work and conditions of employment permitted for minors 14 and 15 years of age.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... minors 14 and 15 years of age. 570.35 Section 570.35 Labor Regulations Relating to Labor (Continued) WAGE... and conditions of employment permitted for minors 14 and 15 years of age. (a) Hours standards. Except... provided, for any youth 14 or 15 years of age who: (i) Has graduated from high school; (ii) Has...

  11. 29 CFR 570.35 - Hours of work and conditions of employment permitted for minors 14 and 15 years of age.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... minors 14 and 15 years of age. 570.35 Section 570.35 Labor Regulations Relating to Labor (Continued) WAGE... and conditions of employment permitted for minors 14 and 15 years of age. (a) Hours standards. Except... provided, for any youth 14 or 15 years of age who: (i) Has graduated from high school; (ii) Has...

  12. Effects of Hourly, Low-Incentive, and High-Incentive Pay on Simulated Work Productivity: Initial Findings with a New Laboratory Method

    ERIC Educational Resources Information Center

    Oah, Shezeen; Lee, Jang-Han

    2011-01-01

    The failures of previous studies to demonstrate productivity differences across different percentages of incentive pay may be partially due to insufficient simulation fidelity. The present study compared the effects of different percentages of incentive pay using a more advanced simulation method. Three payment methods were tested: hourly,…

  13. Effect of Stagger on the Vibroacoustic Loads from Clustered Rockets

    NASA Technical Reports Server (NTRS)

    Rojo, Raymundo; Tinney, Charles E.; Ruf, Joseph H.

    2016-01-01

    The effect of stagger startup on the vibro-acoustic loads that form during the end- effects-regime of clustered rockets is studied using both full-scale (hot-gas) and laboratory scale (cold gas) data. Both configurations comprise three nozzles with thrust optimized parabolic contours that undergo free shock separated flow and restricted shock separated flow as well as an end-effects regime prior to flowing full. Acoustic pressure waveforms recorded at the base of the nozzle clusters are analyzed using various statistical metrics as well as time-frequency analysis. The findings reveal a significant reduction in end- effects-regime loads when engine ignition is staggered. However, regardless of stagger, both the skewness and kurtosis of the acoustic pressure time derivative elevate to the same levels during the end-effects-regime event thereby demonstrating the intermittence and impulsiveness of the acoustic waveforms that form during engine startup.

  14. Staggered fermions, zero modes, and flavor-singlet mesons

    SciTech Connect

    Donald, Gordon C; Davies, Christine T.H.; Follana, Eduardo; Kronfeld, Andreas S.

    2011-09-12

    We examine the taste structure of eigenvectors of the staggered-fermion Dirac operator. We derive a set of conditions on the eigenvectors of modes with small eigenvalues (near-zero modes), such that staggered fermions reproduce the 't Hooft vertex in the continuum limit. We also show that, assuming these conditions, the correlators of flavor-singlet mesons are free of contributions singular in 1/m, where m is the quark mass. This conclusion holds also when a single flavor of sea quark is represented by the fourth root of the staggered-fermion determinant. We then test numerically, using the HISQ action, whether these conditions hold on realistic lattice gauge fields. We find that the needed structure does indeed emerge.

  15. Staggered fermions, zero modes, and flavor-singlet mesons

    DOE PAGES

    Donald, Gordon C; Davies, Christine T.H.; Follana, Eduardo; Kronfeld, Andreas S.

    2011-09-12

    We examine the taste structure of eigenvectors of the staggered-fermion Dirac operator. We derive a set of conditions on the eigenvectors of modes with small eigenvalues (near-zero modes), such that staggered fermions reproduce the 't Hooft vertex in the continuum limit. We also show that, assuming these conditions, the correlators of flavor-singlet mesons are free of contributions singular in 1/m, where m is the quark mass. This conclusion holds also when a single flavor of sea quark is represented by the fourth root of the staggered-fermion determinant. We then test numerically, using the HISQ action, whether these conditions hold onmore » realistic lattice gauge fields. We find that the needed structure does indeed emerge.« less

  16. Staggered chiral perturbation theory in the two-flavor case

    SciTech Connect

    Du Xining

    2010-07-01

    I study two-flavor staggered chiral perturbation theory in the light pseudoscalar sector. The pion mass and decay constant are calculated through next-to-leading order in the partially-quenched case. In the limit where the strange quark mass is large compared to the light quark masses and the taste splittings, I show that the SU(2) staggered chiral theory emerges from the SU(3) staggered chiral theory, as expected. Explicit relations between SU(2) and SU(3) low energy constants and taste-violating parameters are given. The results are useful for SU(2) chiral fits to asqtad data and allow one to incorporate effects from varying strange quark masses.

  17. Boundary conditions in a meshless staggered particle code

    SciTech Connect

    Libersky, L.D.; Randles, P.W.

    1998-07-01

    A meshless method utilizing two sets of particles and generalized boundary conditions is introduced. Companion sets of particles, one carrying velocity and the other carrying stress, are employed to reduce the undesirable effects of colocation of all field variables and increase accuracy. Boundary conditions implemented within this staggered framework include contact, stress-free, stress, velocity, and symmetry constraints. Several test problems are used to evaluate the method. Of particular importance is the motion of stress particles relative to velocity particles in higher dimensions. Early results show promise, but difficulties remain that must be overcome if the staggered technique is to be successful.

  18. Improved staggered eigenvalues and epsilon regime universality in SU(2)

    NASA Astrophysics Data System (ADS)

    Hart, Alistair

    2006-12-01

    We study the low-lying modes of staggered Dirac operators for quenched SU(2) and show that improvement changes the distribution from lattice-like to continuum-like at lattice spacings rep- resentative of current dynamical SU(3) simulations. Epsilon regime universality predicts different distributions for the low-lying eigenvalues of the continuum and lattice staggered Dirac operators. At lattice spacings around 0.07 fm we show that improved staggered eigenvalues have the continuum distribution (as predicted by the chiral Orthogonal Ensemble of random matrices), whilst unimproved fall on the discrete distribution (as per the chiral Symplectic Ensemble). The crossover is much more rapid than for SU(3). In addition, improved staggered fermions give a good approximation to the Atiyah-Singer index theorem, appear to satisfy the Banks-Casher relation and show clear taste-degeneracy for the non- zero modes. All this indicates that taste-changing interactions are well under control at lattice spacings 0.07 - 0.13 fm, matching our findings for SU(3).

  19. 29 CFR 778.421 - Offset hour for hour.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL... Regular Rate Principles Computing Overtime Pay on the Rate Applicable to the Type of Work Performed in... section 7(e)(5) or for work on “special days” (as under section 7(e)(6), or pursuant to an...

  20. 45 CFR 261.31 - How many hours must a work-eligible individual participate for the family to count in the...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING THAT RECIPIENTS WORK What Are the... assistance benefits provided through the Nutrition Assistance Program in the same manner as a State...

  1. 45 CFR 261.31 - How many hours must a work-eligible individual participate for the family to count in the...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING THAT RECIPIENTS WORK What Are the... assistance benefits provided through the Nutrition Assistance Program in the same manner as a State...

  2. 45 CFR 261.31 - How many hours must a work-eligible individual participate for the family to count in the...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... study leading to a certificate of general equivalence. (d)(1) We will deem a work-eligible individual... assistance benefits provided through the Nutrition Assistance Program in the same manner as a State...

  3. 45 CFR 261.31 - How many hours must a work-eligible individual participate for the family to count in the...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... study leading to a certificate of general equivalence. (d)(1) We will deem a work-eligible individual... assistance benefits provided through the Nutrition Assistance Program in the same manner as a State...

  4. 45 CFR 261.31 - How many hours must a work-eligible individual participate for the family to count in the...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... three activities may also count as participation: job skills training directly related to employment... study leading to a certificate of general equivalence. (d)(1) We will deem a work-eligible...

  5. The Swedish duty hour enigma

    PubMed Central

    2014-01-01

    Background The Swedish resident duty hour limit is regulated by Swedish and European legal frameworks. With a maximum average of 40 working hours per week, the Swedish duty hour regulation is one of the most restrictive in the world. At the same time, the effects of resident duty hour limits have been neither debated nor researched in the Swedish context. As a result, little is known about the Swedish conceptual framework for resident duty hours, their restriction, or their outcomes: we call this “the Swedish duty hour enigma.” This situation poses a further question: How do Swedish residents themselves construct a conceptual framework for duty hour restrictions? Methods A case study was conducted at Karolinska University Hospital, Stockholm – an urban, research-intensive hospital setting. Semi-structured interviews were carried out with 34 residents currently in training in 6 specialties. The empirical data analysis relied on theoretical propositions and was conducted thematically using a pattern-matching technique. The interview guide was based on four main topics: the perceived effect of duty hour restrictions on (1) patient care, (2) resident education, (3) resident well-being, and (4) research. Results The residents did not perceive the volume of duty hours to be the main determinant of success or failure in the four contextual domains of patient care, resident education, resident well-being, and research. Instead, they emphasized resident well-being and a desire for flexibility. Conclusions According to Swedish residents’ conceptual framework on duty hours, the amount of time spent on duty is not a proxy for the quality of resident training. Instead, flexibility, organization, and scheduling of duty hours are considered to be the factors that have the greatest influence on resident well-being, quality of learning, and opportunities to attain the competence needed for independent practice. PMID:25559074

  6. 12 hour shifts the Nambour Hospital experience.

    PubMed

    2007-08-01

    Union members have a lengthy history of campaigning for fair working hours and conditions. The success of such campaigns has led to the implementation of the eight hour working day and the 40 hour and then 38 hour week as industrial standards. More recently though, calls for greater flexibility in their shift arrangements by nurses at Nambour Hospital have led to a voluntary 12 hour shift being implemented in their Intensive Care Unit. While union members are protective of their hard won gains in achieving reduced working hours through the 8 hour day--ICU nurses at Nambour Hospital say the voluntary 12 hour shift initiative goes a way in addressing their work/life balance issues.

  7. Reaction mechanisms and staggering in S+Ni collisions

    NASA Astrophysics Data System (ADS)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Morelli, L.; Baiocco, G.; Bardelli, L.; Barlini, S.; Cannata, F.; Casini, G.; Geraci, E.; Gramegna, F.; Kravchuk, V. L.; Marchi, T.; Moroni, A.; Ordine, A.; Raduta, Ad. R.

    2011-07-01

    The reactions S32+Ni58 and S32+Ni64 are studied at 14.5 A MeV. After a selection of the collision mechanism, we show that important even-odd effects are present in the isotopic fragment distributions when the excitation energy is small. Close to the multifragmentation threshold this staggering appears hidden by the rapid variation of the production yields with the fragment size. Once this effect is accounted for, the staggering appears to be a universal feature of fragment production, slightly enhanced when the emission source is neutron poor. A closer look at the behavior of the production yields as a function of the neutron excess N-Z, reveals that odd-even effects cannot be explained by pairing effects in the nuclear masses alone, but depend in a more complex way on the de-excitation chain.

  8. Regularizing QCD with staggered fermions and the fourth root trick

    NASA Astrophysics Data System (ADS)

    Bernard, Claude

    2006-12-01

    We investigate the properties of staggered-fermion lattice QCD in which the fourth root of the fermion determinant is taken. We show that this theory is non-local at non-zero lattice spacing a, and that the non-locality is caused by the breaking of taste symmetry at a = 0. We then present a renormalization-group based argument that the theory restores taste symmetry in the continuum limit. As a consequence the theory is local in that limit, and falls into the correct universality class. Finally, we argue that the correct effective theory for the physics of Goldstone bosons at a = 0 is given by staggered chiral perturbation theory with the replica trick.

  9. Future of Lattice Calculations with Staggered Sea Quarks

    SciTech Connect

    Gottlieb, Steven

    2011-05-23

    The MILC collaboration for some years has been creating gauge ensembles with 2+1 flavors of asqtad or improved staggered quarks. There are some 40 ensembles covering a wide range of quark mass and lattice spacing, thus allowing control of the chiral and continuum limits. An extensive review of that program has been published in Reviews of Modern Physics. Recently, MILC has begun a new program using HPQCD's highly improved staggered quark (HISQ) action. This action has smaller taste symmetry breaking than asqtad and improved scaling properties. We also include a dynamical charm quark in these calculations. We summarize the achievements of the asqtad program, what has been done so far with HISQ quarks, and then consider what future ensembles will be created and their impact.

  10. B{sub K} in staggered chiral perturbation theory

    SciTech Connect

    Water, Ruth S. van de; Sharpe, Stephen R.

    2006-01-01

    We calculate the kaon B parameter, B{sub K}, to next-to-leading order in staggered chiral perturbation theory. We find expressions for partially quenched QCD with three sea quarks, quenched QCD, and full QCD with m{sub u}=m{sub d}{ne}m{sub s}. We extend the usual power counting to include the effects of using perturbative (rather than nonperturbative) matching factors. Taste breaking enters through the O(a{sup 2}) terms in the effective action, through O(a{sup 2}) terms from the discretization of operators, and through the truncation of matching factors. These effects cause mixing with several additional operators, complicating the chiral and continuum extrapolations. In addition to the staggered expressions, we present B{sub K} at next-to-leading order in continuum PQ{chi}PT for N{sub f}=3 sea quarks with m{sub u}=m{sub d}{ne}m{sub s}.

  11. Cascaded, stagger-tuned, broadband, low-ripple optical amplifiers.

    PubMed

    Saleh, A A; Jopson, R M

    1988-11-01

    We show theoretically that the gain spectrum obtained by cascading two or more semiconductor optical amplifiers can have a ripple amplitude that is significantly smaller than that currently attainable with a single stage of optical amplification. For example, by cascading two stagger-tuned amplifiers, each having 10 dB of coupling loss and facet reflectivities of 10(-3), one can achieve a net (fiber-to-fiber) gain of 30 dB with less than 2 dB of ripple amplitude. We also show that, under some conditions, simple cascading of optical amplifiers, without the stagger tuning and associated control, can lead to low-ripple, high-gain optical amplification.

  12. LES investigation of infinite staggered wind-turbine arrays

    NASA Astrophysics Data System (ADS)

    Yang, Xiaolei; Sotiropoulos, Fotis

    2014-12-01

    The layouts of turbines affect the turbine wake interactions and thus the wind farm performance. The wake interactions in infinite staggered wind-turbine arrays are investigated and compared with infinite aligned turbine arrays in this paper. From the numerical results we identify three types of wake behaviours, which are significantly different from wakes in aligned wind-turbine arrays. For the first type, each turbine wake interferes with the pair of staggered downstream turbine wakes and the aligned downstream turbine. For the second type, each turbine wake interacts with the first two downstream turbine wakes but does not show significant interference with the second aligned downstream turbine. For the third type, each turbine wake recovers immediately after passing through the gap of the first two downstream turbines and has little interaction with the second downstream turbine wakes The extracted power density and power efficiency are also studied and compared with aligned wind-turbine arrays.

  13. 45 CFR 261.32 - How many hours must work-eligible individuals participate for the family to count in the...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING THAT RECIPIENTS WORK... provided through the Nutrition Assistance Program in the same manner as a State must include food stamp... Nutrition Assistance Program in the same manner as a State must include food stamp benefits under...

  14. 45 CFR 261.32 - How many hours must work-eligible individuals participate for the family to count in the...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES ENSURING THAT RECIPIENTS WORK... provided through the Nutrition Assistance Program in the same manner as a State must include food stamp... Nutrition Assistance Program in the same manner as a State must include food stamp benefits under...

  15. Forecasting Credit Hours.

    ERIC Educational Resources Information Center

    Bivin, David; Rooney, Patrick Michael

    1999-01-01

    This study used Tobit analysis to estimate retention probabilities and credit hours at two universities. Tobit was judged as appropriate for this problem because it recognizes the lower bound of zero on credit hours and incorporates this bound into parameter estimates and forecasts. Models are estimated for credit hours in a single year and…

  16. Cracking the Credit Hour

    ERIC Educational Resources Information Center

    Laitinen, Amy

    2012-01-01

    The basic currency of higher education--the credit hour--represents the root of many problems plaguing America's higher education system: the practice of measuring time rather than learning. "Cracking the Credit Hour" traces the history of this time-based unit, from the days of Andrew Carnegie to recent federal efforts to define a credit hour. If…

  17. An interpretation of staggering effects by correlation observables

    NASA Astrophysics Data System (ADS)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Morelli, L.; Baiocco, G.; Bardelli, L.; Barlini, S.; Cannata, F.; Casini, G.; Geraci, E.; Gramegna, F.; Kravchuk, V. L.; Marchi, T.; Moroni, A.; Ordine, A.; Raduta, Ad. R.

    2012-07-01

    The reactions 32S+58,64Ni are studied at 14.5 A MeV. Evidence is found for odd-even effects in isotopic observables of the decay of a projectile-like source. The influence of secondary decays on the staggering is studied with a correlation function technique, showing that odd-even effects are due to interplay between pairing effects in the nuclear masses and in the level densities.

  18. New insights into the Young's modulus of staggered biological composites.

    PubMed

    Bar-On, Benny; Wagner, H Daniel

    2013-03-01

    This communication presents a simplified "mechanics-of-materials" approach for describing the mechanics of staggered composite architectures, such as those arising in a variety of biological tissues. This analysis calculates the effective modulus of the bio-composite and provides physical insights into its elastic behavior. Simplified expressions for high- and low-mineralized tissues are then proposed and the effects of the mineral thickness ratio and aspect ratio on the modulus are demonstrated.

  19. Baryons with Ginsparg-Wilson quarks in a staggered sea

    SciTech Connect

    Tiburzi, Brian C.

    2005-11-01

    We determine the masses and magnetic moments of the octet baryons in chiral perturbation theory formulated for a mixed lattice action of Ginsparg-Wilson valence quarks and staggered sea quarks. Taste-symmetry breaking does not occur at next-to-leading order in the combined lattice spacing and chiral expansion. Expressions derived for masses and magnetic moments are required for addressing lattice artifacts in mixed-action simulations of these observables.

  20. Staggered baryon operators with flavor SU(3) quantum numbers

    SciTech Connect

    Bailey, Jon A.

    2007-06-01

    The construction of the first baryon operators for staggered lattice QCD exploited the taste symmetry to emulate physical quark flavor; contemporary 2+1 flavor simulations explicitly include three physical quark flavors and necessitate interpreting a valence sector with 12 quarks. After discussing expected features of the resulting baryon spectrum, I consider the spectra of operators transforming irreducibly under SU(3){sub F}xGTS, the direct product of flavor SU(3){sub F} and the geometrical time-slice group of the 1-flavor staggered theory. I then describe the construction of a set of maximally local baryon operators transforming irreducibly under SU(3){sub F}xGTS and enumerate this set. In principle, the operators listed here could be used to extract the masses of all the lightest spin-(1/2) and spin-(3/2) baryon resonances of staggered QCD. Using appropriate operators from this set in partially quenched simulations should allow for particularly clean 2+1 flavor calculations of the masses of the nucleon, {delta}, {sigma}*, {xi}*, and {omega}{sup -}.

  1. Staggered chiral perturbation theory at next-to-leading order

    SciTech Connect

    Sharpe, Stephen R.; Van de Water, Ruth S.

    2005-06-01

    We study taste and Euclidean rotational symmetry violation for staggered fermions at nonzero lattice spacing using staggered chiral perturbation theory. We extend the staggered chiral Lagrangian to O(a{sup 2}p{sup 2}), O(a{sup 4}), and O(a{sup 2}m), the orders necessary for a full next-to-leading order calculation of pseudo-Goldstone boson masses and decay constants including analytic terms. We then calculate a number of SO(4) taste-breaking quantities, which involve only a small subset of these next-to-leading order operators. We predict relationships between SO(4) taste-breaking splittings in masses, pseudoscalar decay constants, and dispersion relations. We also find predictions for a few quantities that are not SO(4) breaking. All these results hold also for theories in which the fourth root of the fermionic determinant is taken to reduce the number of quark tastes; testing them will therefore provide evidence for or against the validity of this trick.

  2. Taste symmetry breaking with hypercubic-smeared staggered fermions

    SciTech Connect

    Bae, Taegil; Adams, David H.; Kim, Hyung-Jin; Kim, Jongjeong; Kim, Kwangwoo; Lee, Weonjong; Jung, Chulwoo; Sharpe, Stephen R.

    2008-05-01

    We study the impact of hypercubic (HYP) smearing on the size of taste-breaking for staggered fermions, comparing to unimproved and to asqtad-improved staggered fermions. As in previous studies, we find a substantial reduction in taste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on lattices with spacing a{approx_equal}0.1 fm). In addition, we observe that discretization effects of next-to-leading order in the chiral expansion (O(a{sup 2}p{sup 2})) are markedly reduced by HYP smearing. Compared to asqtad valence fermions, we find that taste-breaking in the pion spectrum is reduced by a factor of 2.5-3, down to a level comparable to the expected size of generic O(a{sup 2}) effects. Our results suggest that, once one reaches a lattice spacing of a{approx_equal}0.09 fm, taste-breaking will be small enough after HYP smearing that one can use a modified power counting in which O(a{sup 2})<

  3. Staggers in horses grazing paspalum infected with Claviceps paspali.

    PubMed

    Cawdell-Smith, A J; Scrivener, C J; Bryden, W L

    2010-10-01

    Invasion of the flowering heads of grasses by Claviceps spp. can produce sclerotia (ergots) containing several toxins. Ingestion of these toxins, through the consumption of paspalum (Paspalum dilatatum), can induce a range of clinical symptoms, including staggers. Cattle are the most commonly affected species, but although sheep and horses have been reported affected there are no published descriptions of paspalum staggers in horses. We describe two occurrences of paspalum staggers, the first in three Australian Stockhorse foals and the second in mature Standardbred horses. All three foals presented with ataxia in all limbs after consuming infected paspalum. One foal died from misadventure and the other two recovered within 1 week of removal from the infected paddock. In the second case, two of eight mares and geldings grazing in an irrigation channel developed hindquarter paresis. After removal of all horses from the area, one of the affected horses continued to deteriorate. Both horses were treated with antibiotics. The more severely affected horse was also treated with fluids and electrolytes, but had to be euthanased. The second affected horse recovered after 2 days. Paspalum pastures should inspected for Claviceps paspali infection before the introduction of horses. PMID:20854295

  4. Calculation of fluid flows with staggered and nonstaggered curvilinear nonorthogonal grids. I - The theory. II - A comparison

    NASA Astrophysics Data System (ADS)

    Melaaen, M. C.

    1992-02-01

    Tensor calculus is presently employed to furnish both necessary coordinate and velocity transformations in the present use of two different finite-volume methods for discretization of conservation equations in 3D curvilinear nonorthogonal coordinates. While one method is based on the nonstaggered grid arrangement and employs Cartesian velocity components as dependent variables in the momentum equations, the other combines a staggered grid arrangement with physical covariant velocity projections in a locally fixed coordinate system. In the second part of this work, a comparative evaluation of the two methods indicates that while results of comparable accuracy are achieved after a similar number of iterations, the staggered method may be recommended for curvilinear nonorthogonal coordinate problems due to its reduced memory and computational requirements.

  5. An experimental investigation of wind flow over tall towers in staggered form

    NASA Astrophysics Data System (ADS)

    Anwar, Proma; Islam, Md. Quamrul; Ali, Mohammad

    2016-07-01

    In this research work an experiment is conducted to see the effect of wind loading on square, pentagonal and Hexagonal shape cylinders in staggered form. The experiment is done in an open circuit wind tunnel at a Reynolds number of 4.23×104 based on the face width of the cylinder across the flow direction. The flow velocity has been kept uniform throughout the experiment at 14.3 m/s. The test has been conducted for single cylinders first and then in staggered form. Angle of attack is chosen at a definite interval. The static pressure at different locations of the cylinder is measured by inclined multi-manometer. From the surface static pressure readings pressure coefficients are calculated first, then drag and lift coefficients are calculated using numerical Integration Method. These results will surely help engineers to design buildings with such shapes more efficiently. All the results are expressed in non-dimensional form, so they can be applied for prototype buildings and determine the wind loading at any wind speed on structures of similar external shapes.

  6. Test of {Delta}I = 2 staggering in the superdeformed bands of {sup 194}Hg

    SciTech Connect

    Kruecken, R.; Deleplanque, M.A.; Hackman, G.

    1996-11-01

    Superdeformed (SD) states in {sup 194}Hg were populated in {sup 150}Nd({sup 48}Ca,4n) using a 201 MeV {sup 48}Ca beam from the 88- inch cyclotron. A high statistics experiment was done to test for the previously reported evidence for a {Delta}I = 2 staggering in the three SD bands in {sup 194}Hg. The transition energies were determined with a precision of at least 60 eV for most transitions. From this improvement, we cannot confirm evidence for an extended regular {Delta}I = 2 staggering in any of the three SD bands of {sup 194}Hg. However, we observe deviations from a smooth reference in the SD bands 2 and 3 which differ from previous results. Oscillation patterns of the {gamma}-ray energies that can be induced by a simple band crossing or level shift are discussed. Even though such level shifts would explain the observed effects, other experimental signatures, such as a crossing band, are needed to fully understand the results of the present work; no such band was found.

  7. Staggered grid lagrangian method with local structured adaptive mesh refinement for modeling shock hydrodynamics

    SciTech Connect

    Anderson, R W; Pember, R B; Elliot, N S

    2000-09-26

    A new method for the solution of the unsteady Euler equations has been developed. The method combines staggered grid Lagrangian techniques with structured local adaptive mesh refinement (AMR). This method is a precursor to a more general adaptive arbitrary Lagrangian Eulerian (ALE-AMR) algorithm under development, which will facilitate the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required. Many of the core issues involved in the development of the ALE-AMR method hinge upon the integration of AMR with a Lagrange step, which is the focus of the work described here. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. These new algorithmic components are first developed in one dimension and are then generalized to two dimensions. Solutions of several model problems involving shock hydrodynamics are presented and discussed.

  8. A staggered approach for the coupling of Cahn-Hilliard type diffusion and finite strain elasticity

    NASA Astrophysics Data System (ADS)

    Areias, P.; Samaniego, E.; Rabczuk, T.

    2016-02-01

    We develop an algorithm and computational implementation for simulation of problems that combine Cahn-Hilliard type diffusion with finite strain elasticity. We have in mind applications such as the electro-chemo-mechanics of lithium ion (Li-ion) batteries. We concentrate on basic computational aspects. A staggered algorithm is proposed for the coupled multi-field model. For the diffusion problem, the fourth order differential equation is replaced by a system of second order equations to deal with the issue of the regularity required for the approximation spaces. Low order finite elements are used for discretization in space of the involved fields (displacement, concentration, nonlocal concentration). Three (both 2D and 3D) extensively worked numerical examples show the capabilities of our approach for the representation of (i) phase separation, (ii) the effect of concentration in deformation and stress, (iii) the effect of strain in concentration, and (iv) lithiation. We analyze convergence with respect to spatial and time discretization and found that very good results are achievable using both a staggered scheme and approximated strain interpolation.

  9. School-to-Work Opportunities. Fair Labor Standards Act and the North Carolina Wage and Hour Act. A Guide to Work-Based Learning, Federal and State Child Labor Laws, Minimum Wage Provisions, and the Provisions of Comparable North Carolina Laws. 3rd Edition.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Labor, Raleigh.

    This guide for work-based learning, the Fair Labor Standards Act (FLSA), and the North Carolina Wage and Hours Act is designed to serve employers, educators, agency placement staff, labor organizations, and all those involved in school-to-work initiatives by helping them to understand a variety of issues related to students in the workplace. Based…

  10. Towards an understanding of staggering effects in dissipative binary collisions

    NASA Astrophysics Data System (ADS)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Morelli, L.; Baiocco, G.; Bardelli, L.; Barlini, S.; Cannata, F.; Casini, G.; Geraci, E.; Gramegna, F.; Kravchuk, V. L.; Marchi, T.; Moroni, A.; Ordine, A.; Raduta, Ad. R.

    2012-02-01

    The reactions S32+58Ni are studied at 14.5 A MeV. Evidence is found for important odd-even effects in isotopic observables of selected peripheral collisions corresponding to the decay of a projectile-like source. The influence of secondary decays on the staggering is studied with a correlation function technique. It is shown that this method is a powerful tool to get experimental information on the evaporation chain, in order to constrain model calculations. Specifically, we show that odd-even effects are due to interplay between pairing effects in the nuclear masses and in the level densities.

  11. Pion and kaon masses in staggered chiral perturbation theory

    NASA Astrophysics Data System (ADS)

    Aubin, C.; Bernard, C.

    2003-08-01

    We show how to compute chiral logarithms that take into account both the O(a2) taste-symmetry breaking of staggered fermions and the fourth-root trick that produces one taste per flavor. The calculation starts from the Lee-Sharpe Lagrangian generalized to multiple flavors. An error in a previous treatment by one of us is explained and corrected. The one loop chiral logarithm corrections to the pion and kaon masses in the full (unquenched), partially quenched, and quenched cases are computed as examples.

  12. Survival analysis in telemetry studies: The staggered entry design

    USGS Publications Warehouse

    Pollock, K.H.; Winterstein, S.R.; Bunck, C.M.; Curtis, P.D.

    1989-01-01

    A simple description of the Kaplan-Meier procedure is presented with an example using northern bobwhite quail survival data. The Kaplan- Meier procedure was then generalized to allow gradual (or staggered) entry of animals into the study, allowing animals being lost (or censored) due to radio failure, radio loss, or emigration of the animal from the study area. Additionally, the applicability and generalization of the log rank test, a test to compare two survival distributions, was demonstrated. Computer program was developed and is available from authors.

  13. Observations on staggered fermions at nonzero lattice spacing

    SciTech Connect

    Bernard, Claude; Golterman, Maarten; Shamir, Yigal

    2006-06-01

    We show that the use of the fourth-root trick in lattice QCD with staggered fermions corresponds to a nonlocal theory at nonzero lattice spacing, but argue that the nonlocal behavior is likely to go away in the continuum limit. We give examples of this nonlocal behavior in the free theory, and for the case of a fixed topologically nontrivial background gauge field. In both special cases, the nonlocal behavior indeed disappears in the continuum limit. Our results invalidate a recent claim that at nonzero lattice spacing an additive mass renormalization is needed because of taste-symmetry breaking.

  14. Turbulent Flow Properties Around a Staggered Wind Farm

    NASA Astrophysics Data System (ADS)

    Chamorro, Leonardo P.; Arndt, R. E. A.; Sotiropoulos, Fotis

    2011-12-01

    The fundamental properties of turbulent flow around a perfectly staggered wind farm are investigated in a wind tunnel. The wind farm consisted of a series of 10 rows by 2-3 columns of miniature wind turbines spaced 5 and 4 rotor diameters in the streamwise and spanwise directions respectively. It was placed in a boundary-layer flow developed over a smooth surface under thermally neutral conditions. Cross-wire anemometry was used to obtain high resolution measurements of streamwise and vertical velocity components at various locations within and above the wind farm. The results show that the staggered configuration is more efficient in terms of momentum transfer from the background flow to the turbines compared to the case of an aligned wind turbine array under similar turbine separations in the streamwise and spanwise directions. This leads to improved power output of the overall wind farm. A simplified analysis suggests that the difference in power output between the two configurations is on the order of 10%. The maximum levels of turbulence intensity in the staggered wind farm were found to be very similar to that observed in the wake of a single wind turbine, differing substantially with that observed in an aligned configuration with similar spacing. The dramatic changes in momentum and turbulence characteristics in the two configurations show the importance of turbine layout in engineering design. Lateral homogenization of the turbulence statistics above the wind farm allows for the development of simple parametrizations for the adjustment of flow properties, similar to the case of a surface roughness transition. The development of an internal boundary layer was observed at the upper edge of the wind farm within which the flow statistics are affected by the superposition of the ambient flow and the flow disturbance induced by the wind turbines. The adjustment of the flow in this layer is much slower in the staggered situation (with respect to its aligned

  15. Film cooling: case of double rows of staggered jets.

    PubMed

    Dorignac, E; Vullierme, J J; Noirault, P; Foucault, E; Bousgarbiès, J L

    2001-05-01

    An experimental investigation of film cooling of a wall in a case of double rows of staggered hot jets (65 degrees C) in an ambient air flow. The wall is heated at a temperature value between the one of the jets and the one of the main flow. Experiments have been carried out for different injection rates, the main flow velocity is maintained at 32 m/s. Association of the measures of temperature profiles by cold wire and the measures of wall temperature by infrared thermography allows us to describe the behaviour of the flows and to propose the best injection which assures a good cooling of the plate. PMID:11460645

  16. Protein viscosity, mineral fraction and staggered architecture cooperatively enable the fastest stress wave decay in load-bearing biological materials.

    PubMed

    Qwamizadeh, Mahan; Zhang, Zuoqi; Zhou, Kun; Zhang, Yong Wei

    2016-07-01

    One of the key functions of load-bearing biological materials, such as bone, dentin and sea shell, is to protect their inside fragile organs by effectively damping dynamic impact. How those materials achieve this remarkable function remains largely unknown. Using systematic finite element analyses, we study the stress wave propagation and attenuation in cortical bone at the nanoscale as a model material to examine the effects of protein viscosity, mineral fraction and staggered architecture on the elastic wave decay. It is found that the staggered arrangement, protein viscosity and mineral fraction work cooperatively to effectively attenuate the stress wave. For a typical mineral volume fraction and protein viscosity, an optimal staggered nanostructure with specific feature sizes and layouts is able to give rise to the fastest stress wave decay, and the optimal aspect ratio and thickness of mineral platelets are in excellent agreement with experimental measurements. In contrary, as the mineral volume fraction or the protein viscosity goes much higher, the structural arrangement is seen having trivial effect on the stress wave decay, suggesting that the damping properties of the composites go into the structure-insensitive regime from the structure-sensitive regime. These findings not only significantly add to our understanding of the structure-function relationship of load-bearing biological materials, and but also provide useful guidelines for the design of bio-inspired materials with superior resistance to impact loading.

  17. B -> d* l nu and b -> d l nu form-factors in staggered chiral perturbation theory

    SciTech Connect

    Laiho, Jack; Van de Water, Ruth S.; /Fermilab

    2005-12-01

    We calculate the B {yields} D and B {yields} D* form factors at zero recoil in Staggered Chiral Perturbation Theory. We consider heavy-light mesons in which only the light (u, d, or s) quark is staggered; current lattice simulations generally use a highly improved action such as the Fermilab or NRQCD action for the heavy (b or c) quark. We work to lowest order in the heavy quark expansion and to next-to-leading order in the chiral expansion. We present results for a partially quenched theory with three sea quarks in which there are no mass degeneracies (the ''1+1+1'' theory) and for a partially quenched theory in which the u and d sea quark masses are equal (the ''2+1'' theory). We also present results for full (2+1) QCD, along with a numerical estimate of the size of staggered discretization errors. Finally, we calculate the finite volume corrections to the form factors and estimate their numerical size in current lattice simulations.

  18. 10 CFR 26.205 - Work hours.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... no reasonable opportunities or accommodations appropriate for restorative sleep. (1) Shift turnover... opportunity and accommodations for restorative sleep (e.g., a nap). (3) Beginning or resuming duties...

  19. 10 CFR 26.205 - Work hours.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... no reasonable opportunities or accommodations appropriate for restorative sleep. (1) Shift turnover... opportunity and accommodations for restorative sleep (e.g., a nap). (3) Beginning or resuming duties...

  20. 10 CFR 26.205 - Work hours.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... no reasonable opportunities or accommodations appropriate for restorative sleep. (1) Shift turnover... opportunity and accommodations for restorative sleep (e.g., a nap). (3) Beginning or resuming duties...

  1. 10 CFR 26.205 - Work hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... no reasonable opportunities or accommodations appropriate for restorative sleep. (1) Shift turnover... opportunity and accommodations for restorative sleep (e.g., a nap). (3) Beginning or resuming duties...

  2. 10 CFR 26.205 - Work hours.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... no reasonable opportunities or accommodations appropriate for restorative sleep. (1) Shift turnover... opportunity and accommodations for restorative sleep (e.g., a nap). (3) Beginning or resuming duties...

  3. Compressibility enhancement in an almost staggered interacting Harper model

    NASA Astrophysics Data System (ADS)

    Friedman, Bat-el; Berkovits, Richard

    2015-03-01

    We discuss the compressibility in the almost staggered fermionic Harper model with repulsive interactions in the vicinity of half-filling. It has been shown by Kraus et al. [Phys. Rev. B 89, 161106(R) (2014)], 10.1103/PhysRevB.89.161106 that for spinless electrons and nearest neighbors electron-electron interactions the compressibility in the central band is enhanced by repulsive interactions. Here we would like to investigate the sensitivity of this conclusion to the spin degree of freedom and longer range interactions. We use the Hartree-Fock (HF) approximation, as well as the density matrix renormalization group (DMRG) calculation to evaluate the compressibility. In the almost staggered Harper model, the central energy band is essentially flat and separated from the other bands by a large gap and therefore, the HF approximation is rather accurate. In both cases the compressibility of the system is enhanced compared to the noninteracting case, although the enhancement is weaker due to the inclusion of Hubbard and longer ranged interactions. We also show that the entanglement entropy is suppressed when the compressibility of the system is enhanced.

  4. Magnetic-free non-reciprocity based on staggered commutation

    PubMed Central

    Reiskarimian, Negar; Krishnaswamy, Harish

    2016-01-01

    Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal–oxide–semiconductor integrated circuit for the first time. PMID:27079524

  5. Artificial Staggered Magnetic Field for Ultracold Atoms in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Morais Smith, Cristiane

    2011-03-01

    Uniform magnetic fields are ubiquitous in nature, but this is not the case for staggered magnetic fields. In this talk, I will discuss an experimental set-up for cold atoms recently proposed by us, which allows for the realization of a ``staggered gauge field'' in a 2D square optical lattice. If the lattice is loaded with bosons, it may be described by an effective Bose-Hubbard Hamiltonian, with complex and anisotropic hopping coefficients. A very rich phase diagram emerges: besides the usual Mott-insulator and zero-momentum condensate, a new phase with a finite momentum condensate becomes the ground-state at strong gauge fields. By using the technique of Feshbach resonance, the dynamics of a coherent superposition of a vortex-carrying atomic condensate and a conventional zero-momentum molecular condensate can also be studied within the same scheme. On the other hand, if the lattice is loaded with fermions, a highly tunable, graphene-like band structure can be realized, without requiring the honeycomb lattice symmetry. When the system is loaded with a mixture of bosons and two-species fermions, several features of the high-Tc phase diagram can be reproduced. A dome-shaped unconventional superconducting region arises, surrounded by a non-Fermi liquid and a Fermi liquid at low and high doping, respectively. We acknowledge financial support from the Netherlands Organization for Scientific Research (NWO).

  6. A subzone reconstruction algorithm for efficient staggered compatible remapping

    SciTech Connect

    Starinshak, D.P. Owen, J.M.

    2015-09-01

    Staggered-grid Lagrangian hydrodynamics algorithms frequently make use of subzonal discretization of state variables for the purposes of improved numerical accuracy, generality to unstructured meshes, and exact conservation of mass, momentum, and energy. For Arbitrary Lagrangian–Eulerian (ALE) methods using a geometric overlay, it is difficult to remap subzonal variables in an accurate and efficient manner due to the number of subzone–subzone intersections that must be computed. This becomes prohibitive in the case of 3D, unstructured, polyhedral meshes. A new procedure is outlined in this paper to avoid direct subzonal remapping. The new algorithm reconstructs the spatial profile of a subzonal variable using remapped zonal and nodal representations of the data. The reconstruction procedure is cast as an under-constrained optimization problem. Enforcing conservation at each zone and node on the remapped mesh provides the set of equality constraints; the objective function corresponds to a quadratic variation per subzone between the values to be reconstructed and a set of target reference values. Numerical results for various pure-remapping and hydrodynamics tests are provided. Ideas for extending the algorithm to staggered-grid radiation-hydrodynamics are discussed as well as ideas for generalizing the algorithm to include inequality constraints.

  7. N and Z odd-even staggering in Kr+Sn collisions at Fermi energies

    NASA Astrophysics Data System (ADS)

    Piantelli, S.; Casini, G.; Maurenzig, P. R.; Olmi, A.; Barlini, S.; Bini, M.; Carboni, S.; Pasquali, G.; Poggi, G.; Stefanini, A. A.; Valdrè, S.; Bougault, R.; Bonnet, E.; Borderie, B.; Chbihi, A.; Frankland, J. D.; Gruyer, D.; Lopez, O.; Le Neindre, N.; Pârlog, M.; Rivet, M. F.; Vient, E.; Rosato, E.; Spadaccini, G.; Vigilante, M.; Bruno, M.; Marchi, T.; Morelli, L.; Cinausero, M.; Degerlier, M.; Gramegna, F.; Kozik, T.; Twaróg, T.; Alba, R.; Maiolino, C.; Santonocito, D.

    2013-12-01

    The odd-even staggering of the yield of final reaction products has been studied as a function of proton (Z) and neutron (N) numbers for the collisions 84Kr+112Sn and 84Kr+124Sn at 35 MeV/nucleon in a wide range of elements (up to Z≈20). The experimental data show that staggering effects rapidly decrease with increasing size of the fragments. Moreover the staggering in N is definitely larger than the one in Z. Similar general features are qualitatively reproduced by the gemini code. Concerning the comparison of the two systems, the staggering in N is in general rather similar, being slightly larger only for the lightest fragments produced in the n-rich system. In contrast the staggering in Z, although smaller than that in N, is sizably larger for the n-poor system with respect to the n-rich one.

  8. Effect of initial stagger selection on the handedness of Amyloid beta helical fibrils

    SciTech Connect

    Ghattyvenkatakrishna, Pavan K; Cheng, Xiaolin; Uberbacher, Edward C

    2013-01-01

    Various structural models for Amyloid $\\beta$ fibrils derived from a variety of experimental techniques are currently available. However, this data cannot differentiate between the relative position of the two arms of the $\\beta$ hairpin called the stagger. Amyloid fibrils of various heirarchical levels form left--handed helices composed of $\\beta$ sheets. However it is unclear if positive, negative and neutral staggers all form the macroscopic left--handed helices. Studying this is important since the success of computational approaches to develop drugs for amyloidic diseases will depend on selecting the physiologically relevant structure of the sheets. To address this issue we have conducted extensive molecular dynamics simulations of Amyloid$\\beta$ sheets of various staggers and show that only negative staggers generate the experimentally observed left--handed helices while positive staggers generate the incorrect right--handed helices. The implications of this result extend in to all amyloidic--aggregation type diseases.

  9. Proposal of a Bulk HTSC Staggered Array Undulator

    SciTech Connect

    Kii, Toshiteru; Kinjo, Ryota; Bakr, Mahmoud A.; Sonobe, Taro; Higashimura, Keisuke; Masuda, Kai; Ohgaki, Hideaki; Yoshida, Kyohei; Zen, Heisyun

    2010-06-23

    We proposed a new type of undulator based on bulk high-T{sub c} superconductors (HTSC) which consists of a single solenoid and a stacked array of bulk HTSC. The main advantage of this configuration is that a mechanical structure is not required to produce and control the undulator field. In order to perform a proof of principle experiment, we have developed a prototype of bulk HTSC staggered array undulator using 11 pairs of DyBaCuO bulk superconductors and a normal conducting solenoid. Experimental results obtained by using the prototype undulator and numerical results obtained by a loop current model based on the Bean mode for a type-II superconductor were compared.

  10. Persistent current in an almost staggered Harper model

    NASA Astrophysics Data System (ADS)

    Vasserman, A.; Berkovits, R.

    2015-08-01

    In this paper we study the persistent current (PC) of a staggered Harper model, close to the half-filling. The Harper model is different than other one dimensional disordered systems which are always localized, since it is a quasi-periodic system with correlated disorder resulting in the fact that it can be in the metallic regime. Nevertheless, the PC for a wide range of parameters of the Harper model does not show typical metallic behavior, although the system is in the metallic regime. This is a result of the nature of the central band states, which are a hybridization of Gaussian states localized in superlattice points. When the superlattice is not commensurate with the system length, the PC behaves as an insulator. Thus even in the metallic regime a typical finite Harper model may exhibit a PC expected from an insulator.

  11. Studying the ρ resonance parameters with staggered fermions

    NASA Astrophysics Data System (ADS)

    Fu, Ziwen; Wang, Lingyun

    2016-08-01

    We deliver a lattice study of ρ resonance parameters with p -wave π π scattering phases, which are extracted by finite-size methods at one center-of-mass frame and four moving frames for six lattice ensembles from the MILC Collaboration with pion masses ranging from 346 to 176 MeV. The effective range formula is applied to describe the scattering phases as a function of the energy covering the resonance region; this allows us to extract ρ resonance parameters and to investigate the quark-mass dependence. Lattice studies with three flavors of Asqtad-improved staggered fermions enable us to use the moving-wall source technique on large lattice spatial dimensions (L =64 ) and small light u /d quarks. Numerical computations are carried out at two lattice spacings, a ≈0.12 and 0.09 fm.

  12. 't Hooft vertices, partial quenching, and rooted staggered QCD

    SciTech Connect

    Bernard, Claude; Golterman, Maarten; Shamir, Yigal; Sharpe, Stephen R.

    2008-06-01

    We discuss the properties of 't Hooft vertices in partially quenched and rooted versions of QCD in the continuum. These theories have a physical subspace, equivalent to ordinary QCD, that is contained within a larger space that includes many unphysical correlation functions. We find that the 't Hooft vertices in the physical subspace have the expected form, despite the presence of unphysical 't Hooft vertices appearing in correlation functions that have an excess of valence quarks (or ghost quarks). We also show that, due to the singular behavior of unphysical correlation functions as the massless limit is approached, order parameters for nonanomalous symmetries can be nonvanishing in finite volume if these symmetries act outside of the physical subspace. Using these results, we demonstrate that arguments recently given by Creutz - claiming to disprove the validity of rooted staggered QCD - are incorrect. In particular, the unphysical 't Hooft vertices do not present an obstacle to the recovery of taste symmetry in the continuum limit.

  13. Staggering Inflation To Stabilize Attitude of a Solar Sail

    NASA Technical Reports Server (NTRS)

    Quadrelli, Marco; West, John

    2007-01-01

    A document presents computational-simulation studies of a concept for stabilizing the attitude of a spacecraft during deployment of such structures as a solar sail or other structures supported by inflatable booms. Specifically, the solar sail considered in this paper is a square sail with inflatable booms and attitude control vanes at the corners. The sail inflates from its stowed configuration into a square sail with four segments and four vanes at the tips. Basically, the concept is one of controlling the rates of inflation of the booms to utilize in mass-distribution properties to effect changes in the system s angular momentum. More specifically, what was studied were the effects of staggering inflation of each boom by holding it at constant length for specified intervals between intervals of increasing length until full length is reached. The studies included sensitivity analyses of effects of variations in mass properties, boom lengths, rates of increase in boom length, initial rates of rotation of the spacecraft, and several asymmetries that could arise during deployment. The studies led to the conclusion that the final attitude of the spacecraft could be modified by varying the parameters of staggered inflation. Computational studies also showed that by feeding back attitude and attitude-rate measurements so that corrective action is taken during the deployment, the final attitude can be maintained very closely to the initial attitude, thus mitigating the attitude changes incurred during deployment and caused by modeling errors. Moreover, it was found that by optimizing the ratio between the holding and length-increasing intervals in deployment of a boom, one could cause deployment to track a desired deployment profile to place the entire spacecraft in a desired attitude at the end of deployment.

  14. Experimental study of turbulence intensity influence for turbulent cross flow in staggered tube bundle using grooved cylinder

    NASA Astrophysics Data System (ADS)

    Sahli, Ouissem; Adjlout, Lahouari; Ladjedel, Omar; Amine Ghazi, Mohamed

    2016-03-01

    The present work is an experimental investigation on the effect of the turbulence intensity variation in a staggered tube bundle equipped with grooves at 90° and 270°.The experiments were carried out in a subsonic wind tunnel. Three Reynolds numbers and three turbulence levels were tested. The pressure distributions and drag forces were measured. Surface visualizations were also performed. The obtained results show that the turbulence intensity for different Reynolds number has an influence on the reduction of the drag coefficient.

  15. An Extension of the Athena++ Code Framework for GRMHD Based on Advanced Riemann Solvers and Staggered-mesh Constrained Transport

    NASA Astrophysics Data System (ADS)

    White, Christopher J.; Stone, James M.; Gammie, Charles F.

    2016-08-01

    We present a new general relativistic magnetohydrodynamics (GRMHD) code integrated into the Athena++ framework. Improving upon the techniques used in most GRMHD codes, ours allows the use of advanced, less diffusive Riemann solvers, in particular HLLC and HLLD. We also employ a staggered-mesh constrained transport algorithm suited for curvilinear coordinate systems in order to maintain the divergence-free constraint of the magnetic field. Our code is designed to work with arbitrary stationary spacetimes in one, two, or three dimensions, and we demonstrate its reliability through a number of tests. We also report on its promising performance and scalability.

  16. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  17. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  18. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  19. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  20. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  1. Staggered Local Density of States around the Vortex in Underdoped Cuprates

    SciTech Connect

    Kishine, Jun-ichiro; Lee, Patrick A.; Wen, Xiao-Gang

    2001-06-04

    We have studied a single vortex with the staggered flux (SF) core based on the SU(2) slave-boson theory of high T{sub c} superconductors. We find that, whereas the center in the vortex core is a SF state, as one moves away from the core center a correlated staggered modulation of the hopping amplitude {chi} and pairing amplitude {Delta} becomes predominant. We predict that in this region the local density of states exhibits staggered modulation when measured on the bonds, which may be directly detected by STM experiments.

  2. Gap and stagger effects on the aerodynamic performance and the wake behind a biplane with endplates

    NASA Astrophysics Data System (ADS)

    Kang, Hantae

    Modern flow diagnostics applied to a very old aerodynamic problem has produced a number of intriguing new results and new insight into previous results. The aerodynamic performance and associated flow physics of the biplane with endplates as a function of variation in gap and stagger were analytically and experimentally investigated. A combination of vortex lattice method, integrated force measurement, streamwise PIV, and Trefftz plane Stereo PIV were used to better understand the flowfield around the biplane with endplates. This study was performed to determine the configuration with the optimal aerodynamic performance and to understand the fluid mechanics behind optimal and suboptimal performance of the configuration. The Vortex Lattice code (AVL) shows that the gap and stagger have the most dramatic effects out of the six parameters studied: gap, stagger, dihedral, decalage, sweep and overhang. The force balance measurements with fourteen biplane configurations of different gaps and staggers show that as gap and stagger increase, the lift efficiency also increases at all angles of attack tested at both Re 60,000 and 120,000. Using the force balance data, a generalized empirical method for the prediction of lift coefficient as a function of gap, stagger and angle of attack has been determined and validated when combined with existing relations for CL--α adjustments for AR and taper effects. The resulting empirical approach allows for a rapid determination of CL for a biplane having different gap, stagger, AR and taper without the need for a complete flowfield analysis. Two Dimensional PIV results show a distinctive pattern in the downwash angle for the different gap and stagger configurations tested. The downwash angle increases with increasing gap and stagger. It is also evident that the change in downwash angle is directly proportional to the change in lift coefficient as would be expected. Increasing gap spacing increases the downwash angle as well. Based on

  3. Heat transfer coefficients for staggered arrays of short pin fins

    NASA Astrophysics Data System (ADS)

    Vanfossen, G. J.

    Short pin fins are often used to increase that heat transfer to the coolant in the trailing edge of a turbine blade. Due primarily to limits of casting technology, it is not possible to manufacture pins of optimum length for heat transfer purposes in the trailing edge region. In many cases the pins are so short that they actually decrease the total heat transfer surface area compared to a plain wall. A heat transfer data base for these short pins is not available in the literature. Heat transfer coefficients on pin and endwall surfaces were measured for several staggered arrays of short pin fins. The measured Nusselt numbers when plotted versus Reynolds numbers were found to fall on a single curve for all surfaces tested. The heat transfer coefficients for the short pin fins (length to diameter ratios of 1/2 and 2) were found to be about a factor of two lower than data from the literature for longer pin arrays (length to diameter ratios of about 8).

  4. Heat transfer coefficients for staggered arrays of short pin fins

    NASA Astrophysics Data System (ADS)

    Vanfossen, G. J.

    1981-03-01

    Short pin fins are often used to increase the heat transfer to the coolant in the trailing edge of a turbine blade. Due primarily to limits of casting technology, it is not possible to manufacture pins of optimum length for heat transfer purposes in the trailing edge region. In many cases the pins are so short that they actually decrease the total heat transfer surface area compared to a plain wall. A heat transfer data base for these short pins is not available in the literature. Heat transfer coefficients on pin and endwall surfaces were measured for several staggered arrays of short pin fins. The measured Nusselt numbers when plotted versus Reynolds numbers were found to fall on a single curve for all surfaces tested. The heat transfer coefficients for the short pin fins (length to diameter ratios of 1/2 and 2) were found to be about a factor of two lower than data from the literature for longer pin arrays (length to diameter ratios of about 8).

  5. Axially staggered seed-blanket reactor fuel module construction

    DOEpatents

    Cowell, Gary K.; DiGuiseppe, Carl P.

    1985-01-01

    A heterogeneous nuclear reactor of the seed-blanket type is provided wher the fissile (seed) and fertile (blanket) nuclear fuels are segregated axially within each fuel element such that fissile and fertile regions occur in an alternating pattern along the length of the fuel element. Further, different axial stacking patterns are used for the fuel elements of at least two module types such that when modules of different types are positioned adjacent to one another, the fertile regions of the modules are offset or staggered. Thus, when a module of one type is surrounded by modules of the second type the fertile regions thereof will be surrounded on all sides by fissile material. This provides enhanced neutron communication both radially and axially, thereby resulting in greater power oscillation stability than other axial arrangements. The arrangements of the fissile and fertile regions in an alternating axial manner minimizes the radial power peaking factors and provides a more optional thermal-hydraulic design than is afforded by radial arrangements.

  6. Odd-even staggering in neutron drip line nuclei

    NASA Astrophysics Data System (ADS)

    Changizi, S. A.; Qi, Chong

    2016-07-01

    We have done systematic Hartree-Fock-Bogoliubov calculations in coordinate space on the one-quasi-particle energies and binding energy odd-even staggering (OES) in semi-magic nuclei with the zero-range volume, mixed and surface pairing forces in order to explore the influence of their density dependence. The odd-N isotopes are calculated within the blocking scheme. The strengths for the pairing forces are determined in two schemes by fitting locally to reproduce pairing gap in 120Sn and globally to all available data on the OES of semi-magic nuclei with Z ≥ 8. In the former calculations, there is a noticeable difference between the neutron mean gaps in neutron-rich O, Ca, Ni and Sn isotopes calculated with the surface pairing and those with the mixed and volume pairing. The difference gets much smaller if the globally optimized pairing strengths are employed. The heavier Pb isotopes show the opposite trend. Moreover, large differences between the mean gap and the OES may be expected in both calculations when one goes towards the neutron drip line.

  7. Rashba coupling amplification by a staggered crystal field

    PubMed Central

    Santos-Cottin, David; Casula, Michele; Lantz, Gabriel; Klein, Yannick; Petaccia, Luca; Le Fèvre, Patrick; Bertran, François; Papalazarou, Evangelos; Marsi, Marino; Gauzzi, Andrea

    2016-01-01

    There has been increasing interest in materials where relativistic effects induce non-trivial electronic states with promise for spintronics applications. One example is the splitting of bands with opposite spin chirality produced by the Rashba spin-orbit coupling in asymmetric potentials. Sizable splittings have been hitherto obtained using either heavy elements, where this coupling is intrinsically strong, or large surface electric fields. Here by means of angular resolved photoemission spectroscopy and first-principles calculations, we give evidence of a large Rashba coupling of 0.25 eV Å, leading to a remarkable band splitting up to 0.15 eV with hidden spin-chiral polarization in centrosymmetric BaNiS2. This is explained by a huge staggered crystal field of 1.4 V Å−1, produced by a gliding plane symmetry, that breaks inversion symmetry at the Ni site. This unexpected result in the absence of heavy elements demonstrates an effective mechanism of Rashba coupling amplification that may foster spin-orbit band engineering. PMID:27089869

  8. Investigation and improvement of the staggered labyrinth seal

    NASA Astrophysics Data System (ADS)

    Lin, Zhirong; Wang, Xudong; Yuan, Xin; Shibukawa, Naoki; Noguchi, Taro

    2015-03-01

    Recent studies on staggered labyrinth seals have focused on the effects of different parameters, such as the pressure ratio and rotational speed on the leakage flow rate. However, few investigations pay sufficient attention to flow details and the sealing mechanism, which would be of practical importance in designing seals having higher performance. This paper establishes a theoretical model to study the seal mechanism, thus revealing that leakage is determined by the pressure ratio and geometric structure. Numerical simulation is implemented to illustrate details of the flow field within the seal structure. Viscous dissipation is used to quantitatively investigate the contribution that each location makes to the seal performance, revealing that orifices and stagnation points are the most important positions in the seal structure, generating the most dissipation. The orifice is carefully studied by using the theoretical model. Experiments for different pressure ratios are conducted and the results match well with those of the theoretical model and numerical simulation, verifying the theoretical model and analysis of the seal mechanism. Three new designs, based on a good understanding of the seal mechanism, are presented, with one reducing leakage by 24.5%.

  9. Spectral properties and chiral symmetry violations of (staggered) domain wall fermions in the Schwinger model

    NASA Astrophysics Data System (ADS)

    Hoelbling, Christian; Zielinski, Christian

    2016-07-01

    We follow up on a suggestion by Adams and construct explicit domain wall fermion operators with staggered kernels. We compare different domain wall formulations, namely the standard construction as well as Boriçi's modified and Chiu's optimal construction, utilizing both Wilson and staggered kernels. In the process, we generalize the staggered kernels to arbitrary even dimensions and introduce both truncated and optimal staggered domain wall fermions. Some numerical investigations are carried out in the (1 +1 )-dimensional setting of the Schwinger model, where we explore spectral properties of the bulk, effective and overlap Dirac operators in the free-field case, on quenched thermalized gauge configurations and on smooth topological configurations. We compare different formulations using the effective mass, deviations from normality and violations of the Ginsparg-Wilson relation as measures of chirality.

  10. Theoretical Foundation for the Index Theorem on the Lattice with Staggered Fermions

    SciTech Connect

    Adams, David H.

    2010-04-09

    A way to identify the would-be zero modes of staggered lattice fermions away from the continuum limit is presented. Our approach also identifies the chiralities of these modes, and their index is seen to be determined by gauge field topology in accordance with the index theorem. The key idea is to consider the spectral flow of a certain Hermitian version of the staggered Dirac operator. The staggered fermion index thus obtained can be used as a new way to assign the topological charge of lattice gauge fields. In a numerical study in U(1) backgrounds in two dimensions it is found to perform as well as the Wilson index while being computationally more efficient. It can also be expressed as the index of an overlap Dirac operator with a new staggered fermion kernel.

  11. Examining B(M1) staggering as a fingerprint for chiral doublet bands

    SciTech Connect

    Qi, B.; Yao, J. M.; Zhang, S. Q.; Wang, S. Y.; Meng, J.

    2009-04-15

    The electromagnetic transitions of the doublet bands with different triaxiality parameter {gamma} are discussed in the particle rotor model with {pi}h{sub 11/2} x {nu}h{sub 11/2}{sup -1} configuration. It is found that B(M1) staggering as well as the resulting B(M1)/B(E2) and B(M1){sub in}/B(M1){sub out} staggering are sensitive to the triaxiality parameter {gamma}, and they associate strongly with the characters of nuclear chirality for 15 deg. {<=}{gamma}{<=}30 deg., i.e., the staggering is weak in the chiral vibration region while strong in the static chirality region. For partner bands with near degenerate energy spectra and similar B(M1) and B(E2) transitions, the strong B(M1) staggering can be used as a fingerprint for the static chirality.

  12. PV Hourly Simulation Tool

    SciTech Connect

    Dean, Jesse; Metzger, Ian

    2010-12-31

    This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes the option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  13. PV Hourly Simulation Tool

    2010-12-31

    This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes themore » option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.« less

  14. An unconditionally stable staggered algorithm for transient finite element analysis of coupled thermoelastic problems

    NASA Technical Reports Server (NTRS)

    Farhat, C.; Park, K. C.; Dubois-Pelerin, Y.

    1991-01-01

    An unconditionally stable second order accurate implicit-implicit staggered procedure for the finite element solution of fully coupled thermoelasticity transient problems is proposed. The procedure is stabilized with a semi-algebraic augmentation technique. A comparative cost analysis reveals the superiority of the proposed computational strategy to other conventional staggered procedures. Numerical examples of one and two-dimensional thermomechanical coupled problems demonstrate the accuracy of the proposed numerical solution algorithm.

  15. An unconditionally stable staggered algorithm for transient finite element analysis of coupled thermoelastic problems

    NASA Technical Reports Server (NTRS)

    Farhat, Charbel; Park, K. C.; Dubois-Pelerin, Yves

    1991-01-01

    An unconditionally stable second order accurate implicit-implicit staggered procedure for the finite element solution of fully coupled thermoelasticity transient problems is proposed. The procedure is stabilized with a semi-algebraic augmentation technique. A comparative cost analysis reveals the superiority of the proposed computational strategy to other conventional staggered procedures. Numerical examples of one- and two-dimensional thermomechanical coupled problems demonstrate the accuracy of the proposed numerical solution algorithm.

  16. Finite volume effects in B{sub K} with improved staggered fermions

    SciTech Connect

    Kim, Jangho; Kim, Hyung-Jin; Lee, Weonjong; Jung, Chulwoo; Sharpe, Stephen R.

    2011-06-01

    We extend our recent unquenched (N{sub f}=2+1 flavor) calculation of B{sub K} using improved staggered fermions by including in the fits the finite volume shift predicted by one-loop staggered chiral perturbation theory. The net result is to lower the result in the continuum limit by 0.6%. This shift is slightly smaller than our previous estimate of finite volume effects based on a direct comparison between different volumes.

  17. {Delta}I = 2 energy staggering in normal deformed dysprosium nuclei

    SciTech Connect

    Riley, M.A.; Brown, T.B.; Archer, D.E.

    1996-12-31

    Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.

  18. Theoretical and practical considerations for staggered production of crops in a BLSS

    NASA Astrophysics Data System (ADS)

    Stutte, G. W.; Mackowiak, C. L.; Yorio, N. C.; Wheeler, A.

    1997-01-01

    A functional Bioregenerative Life Support System (BLSS) will generate oxygen, remove excess carbon dioxide, purify water, and produce food on a continuous basis for long periods of operation. In order to minimize fluctuations in gas exchange, water purification, and yield that are inherent in batch systems, staggered planting and harvesting of the crop is desirable. A 418-d test of staggered production of potato cv. Norland (26-d harvest cycles) using nutrients recovered from inedible biomass was recently completed at Kennedy Space Center. The results indicate that staggered production can be sustained without detrimental effects on life support functions in a CELSS. System yields of H_2O, O_2 and food were higher in staggered than batch plantings. Plants growing in staggered production or batch production on ``aged'' solution initiated tubers earlier, and were shorter than plants grown on ``fresh'' solution. This morphological response required an increase in planting density to maintain full canopy coverage. Plants grown in staggered production used available light more efficiently than the batch planting due to increased sidelighting.

  19. Fixed Costs and Hours Constraints

    ERIC Educational Resources Information Center

    Johnson, William R.

    2011-01-01

    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…

  20. Finite-difference staggered grids in GPUs for anisotropic elastic wave propagation simulation

    NASA Astrophysics Data System (ADS)

    Rubio, Felix; Hanzich, Mauricio; Farrés, Albert; de la Puente, Josep; María Cela, José

    2014-09-01

    The 3D elastic wave equations can be used to simulate the physics of waves traveling through the Earth more precisely than acoustic approximations. However, this improvement in quality has a counterpart in the cost of the numerical scheme. A possible strategy to mitigate that expense is using specialized, high-performing architectures such as GPUs. Nevertheless, porting and optimizing a code for such a platform require a deep understanding of both the underlying hardware architecture and the algorithm at hand. Furthermore, for very large problems, multiple GPUs must work concurrently, which adds yet another layer of complexity to the codes. In this work, we have tackled the problem of porting and optimizing a 3D elastic wave propagation engine which supports both standard- and fully-staggered grids to multi-GPU clusters. At the single GPU level, we have proposed and evaluated many optimization strategies and adopted the best performing ones for our final code. At the distributed memory level, a domain decomposition approach has been used which allows for good scalability thanks to using asynchronous communications and I/O.

  1. Direct Observation of b_2 Vibrational Levels in the ^1B_2 tilde{C} State of SO_2: Precise Measurement of ν_3 Level Staggerings

    NASA Astrophysics Data System (ADS)

    Park, Barratt; Jiang, Jun; Womack, Carrie; Richter, Peter; Field, Robert W.; Whitehill, Andrew Richard; Ono, Shuhei

    2014-06-01

    The ^1B_2 tilde{C} STATE OF SO_2 has been the subject of extensive investigation because it is important in the atmospheric photodissociation of SO_2. The state has a double-minimum potential in the dissociation coordinate, ν_3, arising from vibronic interactions, leading to a staggering of vibrational levels with v_3 odd vs. even. We report the first direct observations of the v_3 fundamental and of other levels with b_2 vibrational symmetry (odd v_3). Our work has made use of LIF, IR-UV double resonance, and coherent MODR techniques. Implications of the precision measurement of v_3 staggerings to the determination of double-minimum potential barrier and to vibronic coupling will be discussed.

  2. What are 12-hour shifts good for?

    PubMed

    In the UK many hospitals use 12-hour shifts, believing it to be a cost-efficient means of providing 24-hour nursing care on wards. While healthcare organisations need to find ways to deliver nursing care around the clock and efficiency is a key consideration, nurse leaders have raised concerns about ' whether nurses can function effectively and safely when working long hours (Calkin, 2012; Rogers et al, 2004). In this Policy Plus, we focus specifically on what is known about the impact of shift length on patient safety, employee health and quality of care.

  3. The History of the Student Credit Hour.

    ERIC Educational Resources Information Center

    Shedd, Jessica M.

    2003-01-01

    Traces the history of the student credit hour, designed at the end of the 19th century to translate high school work to college admissions officers. It was expanded to higher education to record elective course work and became widespread in response to calls to document workload and institutional productivity. (SLD)

  4. Shape optimization of staggered ribs in a rotating equilateral triangular cooling channel

    NASA Astrophysics Data System (ADS)

    Moon, Mi-Ae; Park, Min-Jung; Kim, Kwang-Yong

    2014-04-01

    A rotating equilateral triangular cooling channel with staggered square ribs inside the leading edge of a turbine blade has been optimized in this work based on surrogate modeling. The fluid flow and heat transfer in the channel have been analyzed using three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations under uniform heat flux condition. Shear stress transport turbulence model has been used as a turbulence closure. Computational results for area-averaged Nusselt number have been validated compared to the experimental data. The objectives related to the heat transfer rate and pressure drop has been linearly combined with a weighting factor to define the objective function. The angle of the rib, the rib pitch-to-hydraulic diameter ratio, and the rib width-to-hydraulic diameter ratio have been selected as the design variables. Twenty-two design points have been generated by Latin Hypercube sampling, and the values of the objective function have been calculated by the RANS analysis at these points. The surrogate model for the objective function has been constructed using the radial basis neural network method. Through the optimization, the objective function value has been improved by 21.5 % compared to that of the reference geometry.

  5. Modified Omega-k Algorithm for High-Speed Platform Highly-Squint Staggered SAR Based on Azimuth Non-Uniform Interpolation

    PubMed Central

    Zeng, Hong-Cheng; Chen, Jie; Liu, Wei; Yang, Wei

    2015-01-01

    In this work, the staggered SAR technique is employed for high-speed platform highly-squint SAR by varying the pulse repetition interval (PRI) as a linear function of range-walk. To focus the staggered SAR data more efficiently, a low-complexity modified Omega-k algorithm is proposed based on a novel method for optimal azimuth non-uniform interpolation, avoiding zero padding in range direction for recovering range cell migration (RCM) and saving in both data storage and computational load. An approximate model on continuous PRI variation with respect to sliding receive-window is employed in the proposed algorithm, leaving a residual phase error only due to the effect of a time-varying Doppler phase caused by staggered SAR. Then, azimuth non-uniform interpolation (ANI) at baseband is carried out to compensate the azimuth non-uniform sampling (ANS) effect resulting from continuous PRI variation, which is further followed by the modified Omega-k algorithm. The proposed algorithm has a significantly lower computational complexity, but with an equally effective imaging performance, as shown in our simulation results. PMID:25664433

  6. FAS multigrid calculations of three dimensional flow using non-staggered grids

    NASA Technical Reports Server (NTRS)

    Matovic, D.; Pollard, A.; Becker, H. A.; Grandmaison, E. W.

    1993-01-01

    Grid staggering is a well known remedy for the problem of velocity/pressure coupling in incompressible flow calculations. Numerous inconveniences occur, however, when staggered grids are implemented, particularly when a general-purpose code, capable of handling irregular three-dimensional domains, is sought. In several non-staggered grid numerical procedures proposed in the literature, the velocity/pressure coupling is achieved by either pressure or velocity (momentum) averaging. This approach is not convenient for simultaneous (block) solvers that are preferred when using multigrid methods. A new method is introduced in this paper that is based upon non-staggered grid formulation with a set of virtual cell face velocities used for pressure/velocity coupling. Instead of pressure or velocity averaging, a momentum balance at the cell face is used as a link between the momentum and mass balance constraints. The numerical stencil is limited to 9 nodes (in 2D) or 27 nodes (in 3D), both during the smoothing and inter-grid transfer, which is a convenient feature when a block point solver is applied. The results for a lid-driven cavity and a cube in a lid-driven cavity are presented and compared to staggered grid calculations using the same multigrid algorithm. The method is shown to be stable and produce a smooth (wiggle-free) pressure field.

  7. 12-hour shifts: job satisfaction of nurses.

    PubMed

    Todd, C; Robinson, G; Reid, N

    1993-09-01

    A before and after study was carried out amongst staff of 10 wards of a county hospital before and after the introduction of a 12-hour shift system for nurses. The purpose was to investigate the impact of the shift system on job satisfaction. Some 320 nurses covering all qualified and unqualified grades were surveyed using a standard job satisfaction attitude scale. It was found that under the 12-hour shift both intrinsic and extrinsic factors of job satisfaction had been detrimentally affected. Considerable dissatisfaction was expressed about hours of work, conditions of work and the impact of the shift on domestic and social arrangements. The vast majority (83%) reported that they did not want to go on working the shift and there was support for the view that recruitment to nursing would be adversely affected by the shift.

  8. Production of tremorgenic toxins by Penicillium janthinellum Biourge: a possible aetiological factor in ryegrass staggers.

    PubMed

    Lanigan, G W; Payne, A L; Cockrum, P A

    1979-02-01

    Topsoil, herbage and faeces collected during an outbreak of ryegrass staggers in sheep were examined for tremorgenic penicillia. No such fungi were recovered from the plant material, but they were found among the predominant fungi in the soil and faecal samples. The commonest species of Penicillium, and almost the only tremorgenic species encountered, was Penicillium janthinellum Biourge. When fed to sheep, the mycelium of this fungus evoked a number of the clinical signs seen in field cases of ryegrass staggers. Two tremorgenic toxins were isolated from the mycelial felts and available evidence indicates that they are verruculogen and fumitremorgin A. P. janthinellum also produced these tremorgens when cultured in moist, autoclaved soil, but not in unheated soil. The results obtained from this study are in accord with the hypothesis that ryegrass staggers is caused by tremorgenic mycotoxins. PMID:475667

  9. Perturbative matching of the staggered four-fermion operators for {epsilon}'/{epsilon}

    SciTech Connect

    Lee, Weonjong

    2001-09-01

    Using staggered fermions, we calculate the perturbative corrections to the bilinear and four-fermion operators that are used in the numerical study of weak matrix elements for {epsilon}'/{epsilon}. We present results for one-loop matching coefficients between continuum operators, calculated in the naive dimensional regularization (NDR) scheme, and gauge invariant staggered fermion operators. In particular, we concentrate on Feynman diagrams of the current-current insertion type. We also present results for the tadpole improved operators. These results, combined with existing results for penguin diagrams, provide a complete one-loop renormalization of the staggered four-fermion operators. Therefore, using our results, it is possible to match a lattice calculation of K{sup 0}-{bar K}{sup 0} mixing and K{yields}{pi}{pi} decays to the continuum NDR results with all corrections of O(g{sup 2}) included.

  10. Influence of the mineral staggering on the elastic properties of the mineralized collagen fibril in lamellar bone.

    PubMed

    Vercher-Martínez, Ana; Giner, Eugenio; Arango, Camila; Fuenmayor, F Javier

    2015-02-01

    In this work, a three-dimensional finite element model of the staggered distribution of the mineral within the mineralized collagen fibril has been developed to characterize the lamellar bone elastic behavior at the sub-micro length scale. Minerals have been assumed to be embedded in a collagen matrix, and different degrees of mineralization have been considered allowing the growth of platelet-shaped minerals both in the axial and the transverse directions of the fibril, through the variation of the lateral space between platelets. We provide numerical values and trends for all the elastic constants of the mineralized collagen fibril as a function of the volume fraction of mineral. In our results, we verify the high influence of the mineral overlapping on the mechanical response of the fibril and we highlight that the lateral distance between crystals is relevant to the mechanical behavior of the fibril and not only the mineral overlapping in the axial direction.

  11. Chiral transition and deconfinement transition in QCD with the highly improved staggered quark (HISQ) action

    SciTech Connect

    Petreczky P.; Bazavov, A.

    2011-10-11

    We report preliminary results on the chiral and deconfinement aspects of the QCD transition at finite temperature using the Highly Improved Staggered Quark (HISQ) action on lattices with temporal extent of N{sub {tau}} = 6 and 8. The chiral aspects of the transition are studied in terms of quark condensates and the disconnected chiral susceptibility. We study the deconfinement transition in terms of the strange quark number susceptibility and the renormalized Polyakov loop. We made continuum estimates for some quantities and find reasonably good agreement between our results and the recent continuum extrapolated results obtained with the stout staggered quark action.

  12. Performance of staggered quadrature modulations over nonlinear satellite channels with uplink noise and intersymbol interference

    NASA Technical Reports Server (NTRS)

    Simon, M. K.; Divsalar, D.; Omura, J. K.

    1982-01-01

    In this paper, the performance of staggered quadrature modulations over nonlinear satellite channels is analyzed. The effects of uplink noise and intersymbol interference caused by transmitter filtering are included. The approach taken employs computational techniques based on moments of the interference. The expressions for the system bit error rate are derived for a general transponder model characterized by AM-AM and AM-PM conversion characteristics. Specific numerical results are presented for a hard-limited satellite repeater using staggered quadrature overlapped raised cosine (SQORC) and minimum-shift-keying (MSK) modulations.

  13. Horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications.

    PubMed

    Ma, Hongcai; Wu, Lin

    2015-07-10

    We present the design of a horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications. This solar concentrator consists of an array of telecentric primary concentrators, a horizontally staggered lightguide layer, and a vertically tapered lightguide layer. The primary concentrator is realized by two plano-aspheric lenses with lateral movement and maintains a high F-number over an angle range of ±23.5°. The results of the simulations show that the solar concentrator achieves a high concentration ratio of 500× with ±0.5° of acceptance angle by a single-axis tracker and dual lateral translation stages.

  14. Differentiation operation in the wave equation for the pseudospectral method with a staggered mesh

    NASA Astrophysics Data System (ADS)

    Zhao, Z.; Xu, J.; Horiuchi, S.

    2001-05-01

    In the present analysis we introduced a calculation strategy of the staggered grid differentiation by using the real value FFT and real inverted FFT for the pseudospectral method and applied the technique to seismic wave simulation. The calculation method introduced here is one third faster on average than the traditional differentiation method by using the complex FFT. The introduced differentiation strategy is very efficient in economy. For example we apply the staggered grid differentiation by real valued FFT to the simulation of seismic wave propagation in inhomogeneous medium. The results show the validity of the present method.

  15. 5 CFR 610.408 - Use of credit hours.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Use of credit hours. 610.408 Section 610.408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.408 Use of credit hours. Members of the Senior...

  16. 5 CFR 610.408 - Use of credit hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Use of credit hours. 610.408 Section 610.408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.408 Use of credit hours. Members of the Senior...

  17. 5 CFR 610.408 - Use of credit hours.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Use of credit hours. 610.408 Section 610.408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.408 Use of credit hours. Members of the Senior...

  18. 5 CFR 610.408 - Use of credit hours.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Use of credit hours. 610.408 Section 610.408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.408 Use of credit hours. Members of the Senior...

  19. 5 CFR 610.408 - Use of credit hours.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Use of credit hours. 610.408 Section 610.408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Flexible and Compressed Work Schedules § 610.408 Use of credit hours. Members of the Senior...

  20. Resident Duty Hours: Enhancing Sleep, Supervision, and Safety

    ERIC Educational Resources Information Center

    Ulmer, Cheryl, Ed.; Wolman, Dianne Miller, Ed.; Johns, Michael M. E., Ed.

    2009-01-01

    Medical residents in hospitals are often required to be on duty for long hours. In 2003 the organization overseeing graduate medical education adopted common program requirements to restrict resident workweeks, including limits to an average of 80 hours over 4 weeks and the longest consecutive period of work to 30 hours in order to protect…

  1. Delinking resident duty hours from patient safety.

    PubMed

    Osborne, Roisin; Parshuram, Christopher S

    2014-01-01

    Patient safety is a powerful motivating force for change in modern medicine, and is often cited as a rationale for reducing resident duty hours. However, current data suggest that resident duty hours are not significantly linked to important patient outcomes. We performed a narrative review and identified four potential explanations for these findings. First, we question the relevance of resident fatigue in the creation of harmful errors. Second, we discuss factors, including workload, experience, and individual characteristics, that may be more important determinants of resident fatigue than are duty hours. Third, we describe potential adverse effects that may arise from--and, therefore, counterbalance any potential benefits of--duty hour reductions. Fourth, we explore factors that may mitigate any risks to patient safety associated with using the services of resident trainees. In summary, it may be inappropriate to justify a reduction in working hours on the grounds of a presumed linkage between patient safety and resident duty hours. Better understanding of resident-related factors associated with patient safety will be essential if improvements in important patient safety outcomes are to be realized through resident-focused strategies. PMID:25561349

  2. Wage and Hour Farm Labor Laws.

    ERIC Educational Resources Information Center

    Hertel, Catherine

    This paper, by a teacher of migrants, summarizes various farm labor laws and child labor laws pertaining to migrant and seasonal workers. The Migrant and Seasonal Agricultural Worker Protection Act of 1983 provides workers with assurances about pay, hours, and working conditions, including safety and health. This legislation permits anyone…

  3. Density functional calculations of a staggered FeSe monolayer on a SrTiO3 (110) surface

    NASA Astrophysics Data System (ADS)

    Wu, Xianxin; Dai, Xia; Liang, Yi; Le, Congcong; Fan, Heng; Hu, Jiangping

    2016-07-01

    We investigate the electronic and magnetic properties of FeSe monolayer on the anisotropic SrTiO3 (110) surface. With compressive strain along the [1 1 ¯0 ] direction from the substrate, the monolayer FeSe possesses a staggered bipartite iron lattice with a height difference around 0.06 Å along the out-of-plane direction. The staggering causes stronger magnetic frustration among the collinear, stagger-dimer, and stagger-trimer antiferromagnetic orders, and the strain elongates one electron and two hole pockets along the strain direction and the remaining hole pocket along the orthogonal direction. The strain-induced band splitting at Γ can also result in a band inversion to drive the system into a topologically nontrivial phase. The absence of strong superconducting suppression on the staggered lattice suggests that the superconducting pairings may be insensitive to the modification of interactions and hopping parameters between two Fe sublattices.

  4. Mixed action simulations on a staggered background: Interpretation and result for the 2-flavor QCD chiral condensate

    SciTech Connect

    Hasenfratz, Anna; Hoffmann, Roland

    2006-12-01

    Growing evidence indicates that in the continuum limit the rooted staggered action is in the correct QCD universality class, the nonlocal terms arising from taste breaking can be viewed as lattice artifacts. In this paper we consider the 2-flavor Asqtad staggered action at lattice spacing a{approx_equal}0.13 fm and probe the properties of the staggered configurations by an overlap valence Dirac operator. By comparing the distribution of the overlap eigenmodes to continuum QCD predictions we investigate if/when the lattice artifacts are small as a function of the staggered quark mass. We define a matching overlap quark mass where the lattice corrections are minimal for the topological susceptibility and from the eigenmode distribution we predict the 2-flavor chiral condensate. Our results indicate that the staggered configurations are consistent with 2-flavor continuum QCD up to small lattice artifacts, and predict a consistent value for the infinite volume chiral condensate.

  5. Accreditation and the Credit Hour.

    ERIC Educational Resources Information Center

    Wellman, James V.

    2003-01-01

    Reviews the role that accreditation plays in defining and enforcing the credit-hour measure. Regional accreditation agencies are generally more flexible in terms of defining credit hours than are national agencies, which are more rigid in their expectations. Specialized accrediting agencies usually make the least mention of credit units. (SLD)

  6. Is the Office Hour Obsolete?

    ERIC Educational Resources Information Center

    Behrens, Susan

    2013-01-01

    A colleague can't make a coffee date at a time the author proposes because it would conflict with his office hour. No student has actually made an appointment with him during the hour, but he is committed to being in his office as promised in case someone drops by. The author's reaction to her colleague's faithfulness to his posted office hour…

  7. Strategic Alliances between Chinese and Foreign Universities: Was a Staggered Form of Entry Used?

    ERIC Educational Resources Information Center

    Willis, Mike

    2001-01-01

    Explored whether foreign universities moved through levels of alliance with China as a form of staggered market entry. Found almost no movement between levels of alliance, and that high levels of commitment were required at all levels to make an alliance successful. This indicates that foreign universities should be careful to establish alliances…

  8. Odd-even staggering in the neutron-proton interaction and nuclear mass models

    NASA Astrophysics Data System (ADS)

    Cheng, Y. Y.; Zhao, Y. M.; Arima, A.

    2015-02-01

    In this paper we study odd-even staggering of the empirical neutron-proton interaction between the last neutron and the last proton, denoted as δ V1 n -1 p , and its consequence in the Garvey-Kelson mass relations (GKs) and nuclear mass models. The root-mean-squared deviations of predicted masses respectively for even-A and odd-A nuclei by using two combinatorial GKs suggest a large odd-even staggering of δ V1 n -1 p between even-odd and odd-even nuclei, while the odd-even difference of δ V1 n -1 p between even-even and odd-odd nuclei is much smaller. The contribution of the odd-even staggering of δ V1 n -1 p between even-A and odd-A nuclei in deviations of theoretical δ V1 n -1 p values of the Duflo-Zuker model and the improved Weizs a ̈cker -Skyrme model are well represented by an isospin-dependent term. The consideration of this odd-even staggering improves our description of binding energies and one-neutron separation energies in both the Duflo-Zuker model and the improved Weizs a ̈cker -Skyrme model.

  9. Aerodynamic characteristics of a square cylinder with a rod in a staggered arrangement

    NASA Astrophysics Data System (ADS)

    Zhang, P. F.; Wang, J. J.; Lu, S. F.; Mi, J.

    2005-04-01

    The aerodynamic characteristics of a square cylinder with an upstream rod in a staggered arrangement were examined. The pressure measurement was conducted in a wind tunnel at a Reynolds number of ReD=82,000 (based on the width of the square cylinder) and the flow visualization was carried out in a water tunnel with the hydrogen bubble technique at ReD=5,200. When the rod and the square cylinder were in tandem, the reduction of drag was mainly caused by the increase of the rear suction pressure. When the staggered angle was introduced, the shield and disturbance effect of the rod on the square cylinder diminished, which results in the increase of the cylinder drag. The side force induced by the staggered angle is small (the maximum value is 20% of the drag of the isolate square cylinder). There were six different flow modes with various staggered angles and spacing ratios, and the corresponding flow patterns are presented in present paper.

  10. The use of circumferentially varying stagger guide vanes in an axial flow pump or compressor

    NASA Astrophysics Data System (ADS)

    Horlock, J. H.

    1990-04-01

    An actuator disk analysis is given of the flow through a guide vane and rotor combination. It is shown that changes in total pressure across the rotor are, in general, related to circumferential variations in guide vane outlet angle. In particular, known variations in inlet total pressure may be eliminated by suitable circumferential changes in guide vane stagger.

  11. PQChPT with Staggered Sea and Valence Ginsparg-Wilson Quarks: Vector Meson Masses

    SciTech Connect

    Hovhannes R. Grigoryan; Anthony W. Thomas

    2005-09-16

    We consider partially quenched, mixed chiral perturbation theory with staggered sea and Ginsparg-Wilson valence quarks in order to extract a chiral-continuum extrapolation expression for the vector meson mass up to order O(a{sup 2}), at one-loop level. Based on general principles, we accomplish the task without explicitly constructing a sophisticated, heavy vector meson chiral Lagrangian.

  12. Enhancement of optical polarization degree of AlGaN quantum wells by using staggered structure.

    PubMed

    Wang, Weiying; Lu, Huimin; Fu, Lei; He, Chenguang; Wang, Mingxing; Tang, Ning; Xu, Fujun; Yu, Tongjun; Ge, Weikun; Shen, Bo

    2016-08-01

    Staggered AlGaN quantum wells (QWs) are designed to enhance the transverse-electric (TE) polarized optical emission in deep ultraviolet (DUV) light- emitting diodes (LED). The optical polarization properties of the conventional and staggered AlGaN QWs are investigated by a theoretical model based on the k·p method as well as polarized photoluminescence (PL) measurements. Based on an analysis of the valence subbands and momentum matrix elements, it is found that AlGaN QWs with step-function-like Al content in QWs offers much stronger TE polarized emission in comparison to that from conventional AlGaN QWs. Experimental results show that the degree of the PL polarization at room temperature can be enhanced from 20.8% of conventional AlGaN QWs to 40.2% of staggered AlGaN QWs grown by MOCVD, which is in good agreement with the theoretical simulation. It suggests that polarization band engineering via staggered AlGaN QWs can be well applied in high efficiency AlGaN-based DUV LEDs. PMID:27505782

  13. Pharmacokinetic interaction between simvastatin and fenofibrate with staggered and simultaneous dosing: Does it matter?

    PubMed

    Winsemius, Anneke; Ansquer, Jean-Claude; Olbrich, Matthias; van Amsterdam, Peter; Aubonnet, Patrick; Beckmann, Katrin; Driessen, Stefan; van Assche, Hanneke; Piskol, Gabi; Lehnick, Dirk; Mihara, Katsuhiro

    2014-09-01

    Simvastatin and fenofibrate are frequently co-prescribed at staggered intervals for the treatment of dyslipidemia. Since a drug-drug interaction has been reported when the two drugs are given simultaneously, it is of clinical interest to know whether the interaction differs between simultaneous and staggered combinations. A study, assessing the impact of both combinations on the interaction, was conducted with 7-day treatment regimens using simvastatin 40 mg and fenofibrate 145 mg: (A) simvastatin only (evening), (B) simvastatin and fenofibrate (both in evening), and (C) simvastatin (evening) and fenofibrate (morning). Eighty-five healthy subjects received the respective treatments in a randomized, 3-way cross-over study. The pharmacokinetics of simvastatin and the active metabolite simvastatin acid were determined. There was a limited reduction in the AUC0-24h of simvastatin acid of 21 and 29% for simultaneous and staggered combination, respectively. The geometric mean AUC0-24h ratio of simvastatin acid for the two combined dosing regimens (B/C) and 90% confidence interval were 111% (102-121). The interaction apparently had no impact on lipid markers. The findings imply that the observed pharmacokinetic interaction is unlikely clinically relevant, and support the combined use of simvastatin and fenofibrate not only given at staggered interval but also given simultaneously.

  14. The use of staggered scheme and an absorbing buffer zone for computational aeroacoustics

    NASA Technical Reports Server (NTRS)

    Nark, Douglas M.

    1995-01-01

    Various problems from those proposed for the Computational Aeroacoustics (CAA) workshop were studied using second and fourth order staggered spatial discretizations in conjunction with fourth order Runge-Kutta time integration. In addition, an absorbing buffer zone was used at the outflow boundaries. Promising results were obtained and provide a basis for application of these techniques to a wider variety of problems.

  15. Experimental Study of Aligned and Staggered Wind Farms in a Convective Boundary Layer

    NASA Astrophysics Data System (ADS)

    Markfort, Corey; Zhang, Wei; Porte-Agel, Fernando

    2011-11-01

    Wind farm-atmosphere interaction is complicated by turbine configuration and thermal effects on momentum and kinetic energy fluxes. Wind farms of finite length have been modeled as increased surface roughness or as a sparse canopy; however it is not clear which approach is more appropriate. Experiments were conducted in a thermally controlled boundary layer wind tunnel, using a custom x-wire/cold wire and surface heat flux sensors, to understand the effect of aligned versus staggered turbine configurations on momentum absorption and flow adjustment in a convective boundary layer (CBL). Results for experiments of a large farm show the span-wise averaged flow statistics exhibit similar turbulent transport properties to that of canopy flows. The wake adjusts within and grows over the farm more quickly for a staggered compared to an aligned farm. Using canopy flow scaling, we show that the flow equilibrates faster and the overall momentum absorption is higher in a staggered compared to an aligned farm. Wake recovery behind a single turbine is facilitated by buoyancy in a CBL (Zhang et al. under review). We find a similar effect in wind farms resulting in reduced effective roughness and momentum absorption. We also find a reduction of surface heat flux for both wind farms, but greater for the staggered farm.

  16. Avoiding Lawsuits for Wage and Hour Violations.

    PubMed

    Silberman, Cherie L

    2016-01-01

    Due to the highly technical language in the wage and hour laws and regulations, employers often find that they have unknowingly violated the Fair Labor Standards Act (FLSA). This can occur because employers have improperly classified an employee as exempt or because employers do not realize that certain time should be paid in full. Improperly classifying employees as exempt or failing to compensate nonexempt employees for all time worked can lead to costly lawsuits, audits, or enforcement actions by the Wage and Hour Division of the Department of Labor. This article discusses the most common FLSA exemptions and provides best practices to avoid liability under the FLSA.

  17. Avoiding Lawsuits for Wage and Hour Violations.

    PubMed

    Silberman, Cherie L

    2016-01-01

    Due to the highly technical language in the wage and hour laws and regulations, employers often find that they have unknowingly violated the Fair Labor Standards Act (FLSA). This can occur because employers have improperly classified an employee as exempt or because employers do not realize that certain time should be paid in full. Improperly classifying employees as exempt or failing to compensate nonexempt employees for all time worked can lead to costly lawsuits, audits, or enforcement actions by the Wage and Hour Division of the Department of Labor. This article discusses the most common FLSA exemptions and provides best practices to avoid liability under the FLSA. PMID:27249874

  18. Turbulent flow and scalar flux through and over aligned and staggered wind farms

    NASA Astrophysics Data System (ADS)

    Markfort, C. D.; Zhang, W.; Porté-Agel, F.

    2012-04-01

    Wind farm-atmosphere interaction is complicated by the effect of turbine array configuration on momentum, scalar and kinetic energy fluxes. Wind turbine arrays are often arranged in rectilinear grids and, depending on the wind direction, may be perfectly aligned or perfectly staggered. The two extreme configurations make up the end members of a spectrum of infinite possible layouts. A wind farm of finite length may be modeled as an added roughness or as a canopy in large-scale weather and climate models. However, it is not clear which analogy is physically more appropriate. Also, surface scalar flux, including heat, evaporation and trace gas (e.g. CO2) fluxes affected by wind farms, need to be properly parameterized in large-scale models. Experiments involving model wind farms in aligned and staggered configurations, consisting of 13 rows with equivalent turbine density, were conducted in a thermally-controlled boundary-layer wind tunnel. Measurements of the turbulent flow were made using a custom x-wire/cold wire within and over the wind farms. Particular focus was placed on studying the effect of wind farm layout on flow adjustment, momentum and scalar fluxes, and turbulent kinetic energy distribution. Results show that the turbulence statistics of the flow exhibit similar turbulent transport properties to those of canopy flows, but retain some characteristic surface layer properties in a limited region above the wind farms as well. The initial wake growth over columns of turbines in the aligned wind farm is faster. However, the overall wake adjusts within and grows more rapidly over the staggered farm. The effective roughness of the staggered farm was found to be significantly larger than that of the aligned farm. The flow equilibrates faster, and the overall momentum absorption is higher for the staggered compared to the aligned farm, which is consistent with canopy scaling. Lower surface heat flux was found for the wind farms compared to the boundary

  19. Constructing gridded hourly temperature data sets

    NASA Astrophysics Data System (ADS)

    Dumitrescu, Alexandru

    2013-04-01

    Air temperature is the main climatological element, with major impact on the earth-atmosphere energy balance. The characteristics of the surface air temperature in locations without meteorological measurements are obtained using spatio-temporal interpolation techniques. Gridded surface meteorological data are essential for evaluating the performance of regional climate models (RCMs), for applying Statistical Downscaling (SD) methods and as input data for hydrological models. In this study we proposed a methodolgy for interpolating hourly surface temperatures. Three gridding methods are compared. A two-step multivariate gridding approach was used. First we interpolated the hourly normal maps, considered as multiannual average (1961-2010), of air temperature for each hour (4 meteorological terms) of a standard year (366 days). In this step, the Residual Kriging method was used with potential predictors derived from DEM and Landcover Corinne. For interpolating the residuals of the regression model we tested 3 gridding methods: Multiquadratic (MQ), Ordinary Kriging (OK) and 3D Kriging (using time as a third dimension). In the second step, we calculated the anomalies of each hour, day, year for the period 1961-2010. The anomalies were interpolated using the same methods applied for gridding regression residuals. The final hourly surface air temperature maps were obtained by summing the maps from first step with the anomlies map. The main data used in this work were the hourly air temperatures of the 4 observation terms (01, 07, 13, 19), measured between 1961-2010 at the weather stations of the Romanian Meteorological Administration. The predictors were derived from SRTM (Shuttle Radar Topography Mission) DEM and from CORINE Land Cover 2000 product. The gridding was performed in a Romanian National Grid (Stereo 70), at 1 km2 spatial resolution, using R language. The study has been financed by the research project Changes in climate extremes and associated impact in

  20. Dynamical QCD+QED simulation with staggered quarks

    SciTech Connect

    Zhou, Ran; Gottlieb, Steven

    2014-11-15

    Electromagnetic effects play an important role in many phenomena such as isospin-symmetry breaking in the hadron spectrum and the hadronic contributions to g-2. We have generalized the MILC QCD code to include the electromagnetic field. In this work, we focus on simulations including charged sea quarks using the RHMC algorithm. We show details of the dynamical QCD+QED simulation algorithm with compact QED. We analyze the code performance and results for hadron-spectrum observables.

  1. Fourth-Order Accurate IDO Scheme Using Gradient-Staggered Interpolation

    NASA Astrophysics Data System (ADS)

    Imai, Yohsuke; Aoki, Takayuki

    An Interpolated Differential Operator (IDO) scheme using a new interpolation function is proposed. The gradient of the dependent variable is calculated at the position shifted by a half grid size from that of the physical value. A fourth-order Hermite-interpolation function is constructed locally using both the value and the gradient defined at staggered positions. The numerical solutions for the Poisson, diffusion, advection and wave equations have fourth-order accuracy in space. In particular, for the Poisson and diffusion equations, the Gradient-Staggered (G-S) IDO scheme shows better accuracy than the original IDO scheme. As a practical application, the Direct Numerical Simulation (DNS) for two-dimensional isotropic homogeneous turbulence is examined and a comparable result with that of the original IDO scheme is obtained. The G-S IDO scheme clearly contributes to high-accurate computations for solving partial differential equations in computational mechanics.

  2. Index theorem and universality properties of the low-lying eigenvalues of improved staggered quarks.

    PubMed

    Follana, E; Hart, A; Davies, C T H

    2004-12-10

    We study various improved staggered quark Dirac operators on quenched gluon backgrounds in lattice QCD generated using a Symanzik-improved gluon action. We find a clear separation of the spectrum into would-be zero modes and others. The number of would-be zero modes depends on the topological charge as expected from the index theorem, and their chirality expectation value is large ( approximately 0.7). The remaining modes have low chirality and show clear signs of clustering into quartets and approaching the random matrix theory predictions for all topological charge sectors. We conclude that improvement of the fermionic and gauge actions moves the staggered quarks closer to the continuum limit where they respond correctly to QCD topology.

  3. Numerical simulation of dam-break problem using staggered finite volume method

    NASA Astrophysics Data System (ADS)

    Budiasih, L. K.; Wiryanto, L. H.

    2016-02-01

    A problem in a dam-break is when a wall separating two sides of water is removed. A shock wave occurs and propagates. The behavior of the wave is interesting to be investigated with respect to the water depth and its wave speed. The aim of this research is to model dam-break problem using the non-linear shallow water equations and solve them numerically using staggered finite volume method. The solution is used to simulate the dam-break on a wet bed. Our numerical solution will be compared to the analytical solution of shallow water equations for dam-break problem. The momentum non-conservative finite volume scheme on a staggered grid will give a good agreement for dam-break problem on a wet bed, for depth ratios greater than 0.25.

  4. Optimal overlap length in staggered architecture composites under dynamic loading conditions

    NASA Astrophysics Data System (ADS)

    Dutta, Abhishek; Tekalur, Srinivasan Arjun; Miklavcic, Milan

    2013-01-01

    Hybrid staggered architecture composites, like nacre and bone, are known for two discernible aspects: superior strength and synergistic toughness. What is lacking is the scientific rationale proving suitability of these materials under impact/time dependent loading. The current investigation aims to address the structure-property correlationship of these materials by development of an analytical model under dynamic rates of loading. Existing literature studies address behavior of staggered materials under quasi-static loading conditions. Critical overlap length was computed for three natural composites-nacre, spider-silk and, collagen in bone/tendon, and showed reasonable agreement with experimental data. Applicability of the analytical approach to predict lap-joint strength has been briefly discussed and quantified against experimental data. Choice of nanometer sized building blocks in natural composites has been addressed and explained from shear transfer efficiency point of view. The potentiality of these composites for use as biomimetic protective material under impact loading has been addressed as well.

  5. Rooting issue for a lattice fermion formulation similar to staggered fermions but without taste mixing

    SciTech Connect

    Adams, David H.

    2008-05-15

    To investigate the viability of the 4th root trick for the staggered fermion determinant in a simpler setting, we consider a 2-taste (flavor) lattice fermion formulation with no taste mixing but with exact taste-nonsinglet chiral symmetries analogous to the taste-nonsinglet U(1){sub A} symmetry of staggered fermions. Creutz's objections to the rooting trick apply just as much in this setting. To counter them we show that the formulation has robust would-be zero modes in topologically nontrivial gauge backgrounds, and that these manifest themselves in a viable way in the rooted fermion determinant and also in the disconnected piece of the pseudoscalar meson propagator as required to solve the U(1) problem. Also, our rooted theory is heuristically seen to be in the right universality class for QCD if the same is true for an unrooted mixed fermion action theory.

  6. Biomimetic staggered composites with highly enhanced energy dissipation: Modeling, 3D printing, and testing

    NASA Astrophysics Data System (ADS)

    Zhang, Pu; Heyne, Mary A.; To, Albert C.

    2015-10-01

    We investigate the damping enhancement in a class of biomimetic staggered composites via a combination of design, modeling, and experiment. In total, three kinds of staggered composites are designed by mimicking the structure of bone and nacre. These composite designs are realized by 3D printing a rigid plastic and a viscous elastomer simultaneously. Greatly-enhanced energy dissipation in the designed composites is observed from both the experimental results and theoretical prediction. The designed polymer composites have loss modulus up to ~500 MPa, higher than most of the existing polymers. In addition, their specific loss modulus (up to 0.43 km2/s2) is among the highest of damping materials. The damping enhancement is attributed to the large shear deformation of the viscous soft matrix and the large strengthening effect from the rigid inclusion phase.

  7. Asymmetric edge modes by staggered potential in honeycomb lattice: Spin splitter

    SciTech Connect

    Chen, Son-Hsien; Sun, Shih-Jye; Su, Yu-Hsin; Chang, Ching-Ray

    2015-05-07

    In honeycomb lattice with staggered potential such as silicene nanoribbon (SN) as used for illustrations here, we show that the lack of inversion symmetry due to buckled structure can lead to asymmetric edge modes where only one edge is utilized in transport, yielding no cross-walk (due to size effect) between edges. We also find asymmetric Hall accumulations formed because of the presence of staggered potential. Applying two opposite out-of-plane electric fields to two adjacent SNs appropriately, so that cross-walk occurs between two internal edge states, the bulk states serve as a spin-splitter that splits two specious of spins (spin-up and spin-down) into those two SNs. The spin-splitter proposed here does not require any magnetic field and thus manipulates spins in a full electric manner.

  8. Hadron spectrum with domain-wall valence quarks on an improved staggered sea

    SciTech Connect

    Richards, David; Edwards, Robert; Orginos, Konstantinos

    2006-07-23

    The hadron spectrum is computed in full QCD using domain-wall valence fermions on an improved staggered sea, for pion masses down to around $350{approx}(/rm MeV)$. Emphasis is laid on the low-lying baryon spectrum. All possible baryon correlators obtainable from local and quasi-local quark sources are computed, using lattice group-theory methods Results are presented for the lowest-lying states in each isospin channel.

  9. The running of the Schroedinger functional coupling from four-flavour lattice QCD with staggered quarks

    SciTech Connect

    Rubio, Paula Perez; Sint, Stefan

    2011-05-23

    We present preliminary results for the running coupling in the Schroedinger functional scheme in QCD with four flavours. A single-component staggered quark field is used on lattices of size (L/a){sup 3}x(L/a{+-}1). This provides us with 2 different regularisations of the same renormalized coupling, and thus some control over the size of lattice artefacts. These are found to be comparatively large, calling for a more refined analysis, which still remains to be done.

  10. A METHOD OF TREATING UNSTRUCTURED CONCAVE CELLS IN STAGGERED-GRID LAGRANGIAN HYDRODYNAMICS

    SciTech Connect

    C. ROUSCULP; D. BURTON

    2000-12-01

    A method is proposed for the treatment of concave cells in staggered-grid Lagrangian hydrodynamics. The method is general enough to be applied to two- and three-dimensional unstructured cells. Instead of defining a cell-point as the geometric average of its nodes (a cell-center), the cell-point is that which equalizes the triangular/tetrahedral area/volume in two/three dimensions. Examples are given.

  11. Chiral perturbation theory for staggered sea quarks and Ginsparg-Wilson valence quarks

    SciTech Connect

    Baer, Oliver; Bernard, Claude; Rupak, Gautam; Shoresh, Noam

    2005-09-01

    We study lattice QCD with staggered sea and Ginsparg-Wilson valence quarks. The Symanzik effective action for this mixed lattice theory, including the lattice spacing contributions of O(a{sup 2}), is derived. Using this effective theory we construct the leading-order chiral Lagrangian. The masses and decay constants of pseudoscalars containing two Ginsparg-Wilson valence quarks are computed at one-loop order.

  12. Re: Penetration Behavior of Opposed Rows of Staggered Secondary Air Jets Depending on Jet Penetration Coefficient and Momentum Flux Ratio

    NASA Technical Reports Server (NTRS)

    Holdeman, James D.

    2016-01-01

    The purpose of this article is to explain why the extension of the previously published C = (S/Ho)sqrt(J) scaling for opposed rows of staggered jets wasn't directly successful in the study by Choi et al. (2016). It is not surprising that staggered jets from opposite sides do not pass each other at the expected C value, because Ho/D and sqrt(J) are much larger than the maximum in previous studies. These, and large x/D's, tend to suggest development of 2-dimensional flow. Although there are distinct optima for opposed rows of in-line jets, single-side injection, and opposed rows of staggered jets based on C, opposed rows of staggered jets provide as good or better mixing performance, at any C value, than opposed rows of in-line jets or jets from single-side injection.

  13. Solar Hot Water Hourly Simulation

    2009-12-31

    The Software consists of a spreadsheet written in Microsoft Excel which provides an hourly simulation of a solar hot water heating system (including solar geometry, solar collector efficiency as a function of temperature, energy balance on storage tank and lifecycle cost analysis).

  14. Energy preservation and entropy in Lagrangian space- and time-staggered hydrodynamic schemes

    NASA Astrophysics Data System (ADS)

    Llor, Antoine; Claisse, Alexandra; Fochesato, Christophe

    2016-03-01

    Usual space- and time-staggered (STS) "leap-frog" Lagrangian hydrodynamic schemes-such as von Neumann-Richtmyer's (1950), Wilkins' (1964), and their variants-are widely used for their simplicity and robustness despite their known lack of exact energy conservation. Since the seminal work of Trulio and Trigger (1950) and despite the later corrections of Burton (1991), it is generally accepted that these schemes cannot be modified to exactly conserve energy while retaining all of the following properties: STS stencil with velocities half-time centered with respect to positions, explicit second-order algorithm (locally implicit for internal energy), and definite positive kinetic energy. It is shown here that it is actually possible to modify the usual STS hydrodynamic schemes in order to be exactly energy-preserving, regardless of the evenness of their time centering assumptions and retaining their simple algorithmic structure. Burton's conservative scheme (1991) is found as a special case of time centering which cancels the term here designated as "incompatible displacements residue." In contrast, von Neumann-Richtmyer's original centering can be preserved provided this residue is properly corrected. These two schemes are the only special cases able to capture isentropic flow with a third order entropy error, instead of second order in general. The momentum equation is presently obtained by application of a variational principle to an action integral discretized in both space and time. The internal energy equation follows from the discrete conservation of total energy. Entropy production by artificial dissipation is obtained to second order by a prediction-correction step on the momentum equation. The overall structure of the equations (explicit for momentum, locally implicit for internal energy) remains identical to that of usual STS "leap-frog" schemes, though complementary terms are required to correct the effects of time-step changes and artificial viscosity

  15. Effects of staggered fermions and mixed actions on the scalar correlator

    SciTech Connect

    Prelovsek, S.

    2006-01-01

    We provide the analytic predictions for the flavor nonsinglet scalar correlator, which will enable determination of the scalar meson mass from the lattice scalar correlator. We consider simulations with 2+1 staggered sea quarks and staggered or chiral valence quarks. At small u/d masses the correlator is dominated by the bubble contribution, which is the intermediate state with two pseudoscalar mesons. We determine the bubble contribution within staggered and mixed chiral perturbation theory. Its effective mass is smaller than the mass of {pi}{eta}, which is the lightest intermediate state in proper 2+1 QCD. The unphysical effective mass is a consequence of the taste breaking that makes possible the intermediate state with mass 2M{sub {pi}}. We find that the scalar correlator can be negative in the simulations with mixed quark actions if the sea- and valence-quark masses are tuned by matching the pion masses M{sub val,val}=M{sub {pi}{sub 5}}.

  16. A fast Poisson solver for unsteady incompressible Navier-Stokes equations on the half-staggered grid

    NASA Technical Reports Server (NTRS)

    Golub, G. H.; Huang, L. C.; Simon, H.; Tang, W. -P.

    1995-01-01

    In this paper, a fast Poisson solver for unsteady, incompressible Navier-Stokes equations with finite difference methods on the non-uniform, half-staggered grid is presented. To achieve this, new algorithms for diagonalizing a semi-definite pair are developed. Our fast solver can also be extended to the three dimensional case. The motivation and related issues in using this second kind of staggered grid are also discussed. Numerical testing has indicated the effectiveness of this algorithm.

  17. 29 CFR 778.419 - Hourly workers employed at two or more jobs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Section 778.419 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF... Type of Work Performed in Overtime Hours (secs. 7(g) (1) and (2)) § 778.419 Hourly workers employed at... work, for which different straight time hourly rates are established, may agree with his employer...

  18. Cross flow induced vibrations in staggered arrays of cylindrical structures

    SciTech Connect

    Marn, J.

    1991-12-31

    Flow induced vibrations cause by instability is the subject of this investigation. The bulk of the work performed is theoretical in nature, the comparison with some of existing experimental data is given for each of four models described. First model encompasses the effects of prescribed motion on the cylinder. Such circumstances occur in the case of vortex shedding initiated instability. The reduced velocity within the cylinder array is low and there is no coupling between the adjacent cylinders. Second model assumes certain form of vibration and corresponding behavior of the perturbed velocity field in temporal and one of spatial coordinates thus transforming partial differential equations into ordinary differential equations and takes into account the motion of the neighboring cylinder. This corresponds to fluid elastic controlled instabilities. The resulting equations are solved analytically. The model is used for better understanding of the equations of cylinder motion as well as for quick estimates of threshold of instability. Third model relaxes an assumption about the form of vibration in spatial direction and uses the vorticity formulation of equation of fluid motion to account for fluid-solid interaction. This model analysis is of two phase (air-water mixture) flow. The void fraction distribution is found to be the single most decisive factor to determine the onset of instability for such a domain. In conclusion, two distinct mechanism were found to be responsible for flow induced vibration caused instabilities, (1) outside source controlled periodic excitation (such as vortex shedding) -- described by the first model and (2) fluid elastic forces -- described by second, third and fourth models. For the values of reduced velocity below 0.7 first model is proposed, for the values above 0.7, the rest.

  19. Quantifying array losses due to spacing and staggering in offshore wind farms (Invited)

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Mirzaeisefat, S.; Lee, S.; Xie, S.

    2013-12-01

    The layout of wind turbines can have an impact on the power production of a wind farm. Design variables that define the layout of wind turbines within a wind farm include: orientation of the rows with respect to the prevailing wind direction, size and shape of the wind farm, spacing between turbines, and alignment of the turbines (i.e., whether in-line or staggered with one another). There are no universal layout recommendations for offshore wind farms, partly because isolating the contribution of each individual design variable is impossible at existing offshore wind farms, where multiple effects overlap non-linearly on one another, and partly because analyzing the sensitivity to design variables requires sophisticated and computer-intensive numerical codes, such as large-eddy simulations (LES), that can simulate the small-scale turbulent features of turbine wakes. The National Renewable Energy Laboratory (NREL) developed the only publicly available and open-source LES code that is capable of resolving wind turbine blades as rotating actuator lines (not fixed disks), includes both neutral and unstable atmospheric conditions (stable case is currently under development), and does not rely on periodic boundary conditions. This code, named Simulator for Offshore/Onshore Wind Farm Applications (SOWFA), is based on OpenFOAM and has been used successfully in the past for turbulent wake simulations. Here we address the issue of quantifying two design variables: turbine spacing (both along and across the prevailing wind direction) and alignment (in-line or staggered for consecutive rows). SOWFA is used to simulate an existing offshore wind farm in Lillgrund (Sweden), consisting of 48 Siemens 2.3 MW turbines with spacing of 3.2D across and 4.3D along the prevailing wind direction and without staggering, where D is the turbine diameter (93 m). This spacing is exceptionally tight, to our knowledge the tightest of all modern wind farms. While keeping the area and the shape of

  20. Quantifying array losses due to spacing and staggering in offshore wind farms (Invited)

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Mirzaeisefat, S.; Lee, S.; Xie, S.

    2011-12-01

    The layout of wind turbines can have an impact on the power production of a wind farm. Design variables that define the layout of wind turbines within a wind farm include: orientation of the rows with respect to the prevailing wind direction, size and shape of the wind farm, spacing between turbines, and alignment of the turbines (i.e., whether in-line or staggered with one another). There are no universal layout recommendations for offshore wind farms, partly because isolating the contribution of each individual design variable is impossible at existing offshore wind farms, where multiple effects overlap non-linearly on one another, and partly because analyzing the sensitivity to design variables requires sophisticated and computer-intensive numerical codes, such as large-eddy simulations (LES), that can simulate the small-scale turbulent features of turbine wakes. The National Renewable Energy Laboratory (NREL) developed the only publicly available and open-source LES code that is capable of resolving wind turbine blades as rotating actuator lines (not fixed disks), includes both neutral and unstable atmospheric conditions (stable case is currently under development), and does not rely on periodic boundary conditions. This code, named Simulator for Offshore/Onshore Wind Farm Applications (SOWFA), is based on OpenFOAM and has been used successfully in the past for turbulent wake simulations. Here we address the issue of quantifying two design variables: turbine spacing (both along and across the prevailing wind direction) and alignment (in-line or staggered for consecutive rows). SOWFA is used to simulate an existing offshore wind farm in Lillgrund (Sweden), consisting of 48 Siemens 2.3 MW turbines with spacing of 3.2D across and 4.3D along the prevailing wind direction and without staggering, where D is the turbine diameter (93 m). This spacing is exceptionally tight, to our knowledge the tightest of all modern wind farms. While keeping the area and the shape of

  1. Hourly temporal distribution of wind

    NASA Astrophysics Data System (ADS)

    Deligiannis, Ilias; Dimitriadis, Panayiotis; Koutsoyiannis, Demetris

    2016-04-01

    The wind process is essential for hydrometeorology and additionally, is one of the basic renewable energy resources. Most stochastic forecast models are limited up to daily scales disregarding the hourly scale which is significant for renewable energy management. Here, we analyze hourly wind timeseries giving emphasis on the temporal distribution of wind within the day. We finally present a periodic model based on statistical as well as hydrometeorological reasoning that shows good agreement with data. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

  2. (Updated) Fort Detrick Gate Hours Change Effective April 10 | Poster

    Cancer.gov

    The Fort Detrick gate hours will change beginning Friday, April 10. The new hours were recently provided by the U.S. Army Garrison (USAG), Fort Detrick. NCI will continue to work with the USAG to address questions that may arise. Note that no changes have been made for facilities outside of the Fort Detrick campus (e.g., the Advanced Technology Research Facility).

  3. 29 CFR 778.202 - Premium pay for hours in excess of a daily or weekly standard.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standard. 778.202 Section 778.202 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION... whose maximum hours standard is 40 hours is hired at the rate of $5.75 an hour and receives, as overtime compensation under his contract, $6.25 per hour for each hour actually worked in excess of 8 per day (or...

  4. 46 CFR 386.1 - Hours of admission to property.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Regimental leave periods and indoctrination training for the fourth class year. The closing of property shall... athletic facilities for authorized activities. During normal working hours, property shall be closed to...

  5. 46 CFR 386.1 - Hours of admission to property.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Regimental leave periods and indoctrination training for the fourth class year. The closing of property shall... athletic facilities for authorized activities. During normal working hours, property shall be closed to...

  6. 46 CFR 386.1 - Hours of admission to property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regimental leave periods and indoctrination training for the fourth class year. The closing of property shall... athletic facilities for authorized activities. During normal working hours, property shall be closed to...

  7. 46 CFR 386.1 - Hours of admission to property.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Regimental leave periods and indoctrination training for the fourth class year. The closing of property shall... athletic facilities for authorized activities. During normal working hours, property shall be closed to...

  8. 46 CFR 386.1 - Hours of admission to property.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Regimental leave periods and indoctrination training for the fourth class year. The closing of property shall... athletic facilities for authorized activities. During normal working hours, property shall be closed to...

  9. Experiments on condensation over in-line and staggered condenser tubes in the presence of non-condensable gases

    NASA Astrophysics Data System (ADS)

    Ramadan, Abdulghani; Yamali, Cemil

    2013-12-01

    The problem of the forced film condensation heat transfer of pure steam and steam-air mixture flowing downward a tier of horizontal cylinders is investigated experimentally. An experimental setup was manufactured and mounted at Middle East Technical University workshop. A set of experiments were conducted to observe the condensation heat transfer phenomenon and to verify the theoretical results. The results of the experimental investigation are presented to show the effect of different parameters on the film condensation heat transfer phenomenon over bundle of tubes. These parameters include; free stream velocity, free stream non-condensable gas (air) mass fractions, free stream temperature to wall temperature difference, the angle of inclination. heat transfer coefficients are evaluated at different working conditions for both inline and staggered arrangements. Results show that; a remarked reduction in the vapor side heat transfer coefficient is noticed when very small amounts of air mass fractions present in the vapor. In addition, it decreases by increasing the temperature difference. On the other hand, it increases by increasing the free stream velocity (Reynolds number). Average heat transfer coefficient at the middle and the bottom cylinders increases by increasing the angle of inclination, whereas, no significant change is observed for that of the upper cylinder. Although some discrepancies are noticed, the present study results are inline and in a reasonable agreement with the theory and experiment in the literature.

  10. Staggered magnetization and low-energy magnon dispersion in the multiferroic skyrmion host Cu2OSeO3

    NASA Astrophysics Data System (ADS)

    Marcus, Guy G.; Trump, Benjamin A.; Kindervater, Jonas; Jones, Lacy L.; Stone, Matthew B.; McQueen, Tyrel M.; Broholm, Collin L.

    We present neutron diffraction and inelastic scattering of the insulating helimagnet, Cu2OSeO3 which provide evidence for staggered magnetization and elucidate the associated low-energy magnon spectrum. The modulation wavelength of approximately λ ~ 50 nm detected at antiferromagnetic Bragg points is of the same length scale as previously reported for the skyrmion lattice. This superstructure evidences the composite nature of the spin-1 tetrahedra that form the topological magnetic structure of the material. To understand the interplay of ferrimagnetism and long wavelength modulated magnetism, we have performed inelastic neutron scattering on a co-aligned sample of chemical vapor transport grown single crystals. We shall present the low-energy magnon dispersion and infer an effective spin Hamiltonian to account for the long-wavelength, low-energy magnetism of Cu2OSeO3. The work at IQM was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Material Sciences and Engineering, under Grant No. DEFG02-08ER46544. GGM also acknowledges support from the NSF-GRFP Grant No. DGE-1232825.

  11. Persistence of odd-even staggering in charged-fragment yields from 112Sn + 58Ni collisions at 35 MeV/nucleon

    NASA Astrophysics Data System (ADS)

    Casini, G.; Piantelli, S.; Maurenzig, P. R.; Olmi, A.; Bardelli, L.; Barlini, S.; Benelli, M.; Bini, M.; Calviani, M.; Marini, P.; Mangiarotti, A.; Pasquali, G.; Poggi, G.; Stefanini, A. A.; Bruno, M.; Morelli, L.; Kravchuk, V. L.; Amorini, F.; Auditore, L.; Cardella, G.; De Filippo, E.; Galichet, E.; La Guidara, E.; Lanzalone, G.; Lanzanó, G.; Maiolino, C.; Pagano, A.; Papa, M.; Pirrone, S.; Politi, G.; Pop, A.; Porto, F.; Rizzo, F.; Russotto, P.; Santonocito, D.; Trifiró, A.; Trimarchi, M.

    2012-07-01

    Odd-even staggering effects on charge distributions are investigated for fragments produced in semiperipheral and central collisions of 112Sn+58Ni at 35 MeV/nucleon. For fragments with Z≤16 one observes a clear overproduction of even charges, which decreases for heavier fragments. Staggering persists up to Z˜30. The staggering appears to be substantially independent of the centrality of the collisions, suggesting that it is mainly related to the last few steps in the decay of hot nuclei.

  12. Heterojunction effect on contact resistance minimization in staggered pentacene thin-film transistors

    NASA Astrophysics Data System (ADS)

    Zhong, Ya-Nan; Gao, Xu; Wang, Chen-Huan; Xu, Jian-Long; Wang, Sui-Dong

    2016-11-01

    The MoO3/pentacene heterojunction is demonstrated to be effective for reducing the contact resistance in staggered organic thin-film transistors. The heterojunction-induced doping is nondestructive and may form a top conducting channel close to the pentacene surface. Contact interface doping and channel doping both significantly reduced the contact resistance. The effect of channel doping was prominent at low gate bias values, which is ascribed to the negligible access resistance owing to the presence of the top channel. Interface doping and channel doping were combined to obtain a complete heterojunction, which exhibited minimized contact resistance for a wide range of gate bias values.

  13. Generalized parton distributions from domain wall valence quarks and staggered sea quarks

    SciTech Connect

    Renner, Dru; Bratt, Jonathan; Edwards, Robert; Engelhardt, Michael; Fleming, George; Haegler, Philipp; Musch, Bernhard; Negele, John; Orginos, Konstantinos; Pochinsky, Andrew; Richards, David; Schroers, Wolfram

    2007-11-01

    Moments of the generalized parton distributions of the nucleon, calculated with a mixed action of domain wall valence quarks and asqtad staggered sea quarks, are presented for pion masses extending down to 359 MeV. Results for the moments of the unpolarized, helicity, and transversity distributions are given and compared to the available experimental measurements. Additionally, a selection of the generalized form factors are shown and the implications for the spin decomposition and transverse structure of the nucleon are discussed. Particular emphasis is placed on understanding systematic errors in the lattice calculation and exploring a variety of chiral extrapolations.

  14. A simplified design of the staggered herringbone micromixer for practical applications

    PubMed Central

    Du, Yan; Zhang, Zhiyi; Yim, ChaeHo; Lin, Min; Cao, Xudong

    2010-01-01

    We demonstrated a simple method for the device design of a staggered herringbone micromixer (SHM) using numerical simulation. By correlating the simulated concentrations with channel length, we obtained a series of concentration versus channel length profiles, and used mixing completion length Lm as the only parameter to evaluate the performance of device structure on mixing. Fluorescence quenching experiments were subsequently conducted to verify the optimized SHM structure for a specific application. Good agreement was found between the optimization and the experimental data. Since Lm is straightforward, easily defined and calculated parameter for characterization of mixing performance, this method for designing micromixers is simple and effective for practical applications. PMID:20697584

  15. A staggered mesh finite difference scheme for the computation of hypersonic Euler flows

    NASA Technical Reports Server (NTRS)

    Sanders, Richard

    1991-01-01

    A shock capturing finite difference method for systems of hyperbolic conservation laws is presented which avoids the need to solve Riemann problems while being competitive in performance with other current methods. A staggered spatial mesh is employed, so that complicated nonlinear waves generated at cell interfaces are averaged over cell interiors at the next time level. The full method combines to form a conservative version of the modified method of characteristics. The advantages of the method are discussed, and numerical results are presented for the two-dimensional double ellipse problem.

  16. Critical behavior in N{sub t}=4 staggered fermion thermodynamics

    SciTech Connect

    Bernard, Claude; DeTar, Carleton; Gottlieb, Steven; Heller, Urs M.; Hetrick, James; Rummukainen, Kari; Sugar, Robert L.; Toussaint, Doug

    2000-03-01

    Quantum chromodynamics with two zero mass flavors is expected to exhibit a phase transition with O(4) critical behavior. Fixing the universality class is important for phenomenology and for facilitating the extrapolation of simulation data to physical quark mass values. Other groups have reported results from lattice QCD simulations with dynamical staggered quarks at N{sub t}=4, which suggest a departure from the expected critical behavior. We have pushed simulations to the largest volumes and smallest quark mass to date. Strong discrepancies in critical exponents and the scaling equation of state persist. (c) 2000 The American Physical Society.

  17. Computational dispersion properties of horizontal staggered grids for atmospheric and ocean models

    NASA Technical Reports Server (NTRS)

    Fox-Rabinovitz, Michael S.

    1991-01-01

    The computational dispersion properties of horizontally and time-horizontally staggered grids utilizing corresponding centered-difference techniques for approximation of the adjustment, or gravity wave equations, are examined in terms of their group velocity characteristics. Results are acquired for oceanic and atmospheric models, the former being characterized by a much smaller Rossby radius of deformation. For all grids considered additional filtering is required to control and even eliminate waves with poor computational dispersion characteristics. Computational dispersion properties along with other computational characteristics and requirements give some guidance for an optimal selection of an appropriate grid for an ocean or atmospheric model.

  18. A comparative study of staggered and cell-centered Lagrangian formulation for multimaterial hydrodynamics

    SciTech Connect

    Francois, Marianne M; Shashkov, Misha J; Lowrie, Robert B; Dendy, Edward D

    2010-10-13

    We compare a staggered Lagrangian formulation with a cell-centered Lagrangian formulation for a two-material compressible flow. In both formulation, we assume a single velocity field and rely on pressure relaxation techniques to close the system of equations. We employ Tipton's mixture model for both formulation. However, for the cell-centered formulation, employing Tipton's model for the mixture cell results in loss of conservation of total energy. We propose a numerical algorithm to correct this energy discrepancy. We test both algorithms on the two-materials Sod shock tube test problem and compare the results with the analytical solution.

  19. Achieving the Best: Gender and the Literacy Hour.

    ERIC Educational Resources Information Center

    Fisher, Helen

    2001-01-01

    A study involving 30 British elementary children investigated the relationship between reading and gender and attitudes towards the literacy hour. Findings indicate boys wanted shorter time spans of learning activities, preferred independent work, and liked computer work. Both sexes liked working in small groups and disliked sharing their work…

  20. Child Care during Nonstandard Work Hours: Research to Policy Resources

    ERIC Educational Resources Information Center

    Ferguson, Daniel

    2016-01-01

    In November 2014, the Child Care and Development Block Grant (CCDBG) Act of 2014 was signed into law, reauthorizing the Child Care and Development Fund (CCDF)--the federal child care subsidy program--for the first time since 1996. In December 2015, the U.S. Office of Child Care issued a Notice of Proposed Rulemaking, which updated CCDF regulations…

  1. Parents' Working Hours: Adolescent Children's Views and Experiences

    ERIC Educational Resources Information Center

    Lewis, Jane; Noden, Philip; Sarre, Sophie

    2008-01-01

    As dual-earner families have become the norm, the different kinds of "time" children spend with parents has become an important issue. We use the 2000 Time Use Survey to identify adolescent children spending time alone at home, and interviews with 50 children aged 14 and 15 to explore young people's experiences. We investigate their views on their…

  2. After-Hours Work Email No Friend of The Family

    MedlinePlus

    ... balance out of kilter by blurring boundaries between business time and personal time. In 2014, researchers at ... men and women, he said. Christina Maslach, a psychology professor emerita at the University of California, Berkeley, ...

  3. 46 CFR 15.1111 - Work hours and rest periods.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... assigned duty as officer in charge of a navigational or engineering watch, or duty as a rating forming part of a navigational or engineering watch, on board any vessel that operates beyond the Boundary Line.... (g) The Master shall post watch schedules where they are easily accessible. They must cover...

  4. Colleges Are Slashing Adjuncts' Hours to Skirt New Rules on Health-Insurance Eligibility

    ERIC Educational Resources Information Center

    Dunn, Sydni

    2013-01-01

    Allison G. Armentrout, an adjunct instructor at Stark State College, does not get paid by the hour. She earns $4,600 to teach two English composition courses. But now she carefully tracks how many hours she works on an electronic time sheet. During a recent week, she spent three hours preparing for her lectures, close to six hours in the…

  5. Is it time to pull the plug on 12-hour shifts?: Part 1. The evidence.

    PubMed

    Geiger-Brown, Jeanne; Trinkoff, Alison M

    2010-03-01

    Shift durations of 12 hours or more are now ubiquitous in hospitals, with currently working staff nurses reporting satisfaction with this shift length, although others who prefer shorter work hours have generally left hospital nursing. Nurse administrators are beginning to question the wisdom of having nurses work extended hours. In part 1 of this 2-part series, the authors provide an update on recent findings that challenge the current scheduling paradigm that supports unsafe long work hours. Part 2 discusses obstacles that nurse administrators face when they "buck the 12-hour trend" and offers guidance for introducing work schedule changes.

  6. Mott Transitions and Staggered Orders in the Three-Component Fermionic System: Variational Cluster Approach

    NASA Astrophysics Data System (ADS)

    Hasunuma, Takumi; Kaneko, Tatsuya; Miyakoshi, Shohei; Ohta, Yukinori

    2016-07-01

    The variational cluster approximation is used to study the ground-state properties and single-particle spectra of the three-component fermionic Hubbard model defined on the two-dimensional square lattice at half filling. First, we show that either a paired Mott state or color-selective Mott state is realized in the paramagnetic system, depending on the anisotropy in the interaction strengths, except around the SU(3) symmetric point, where a paramagnetic metallic state is maintained. Then, by introducing Weiss fields to observe spontaneous symmetry breakings, we show that either a color-density-wave state or color-selective antiferromagnetic state is realized depending on the interaction anisotropy and that the first-order phase transition between these two states occurs at the SU(3) point. We moreover show that these staggered orders originate from the gain in potential energy (or Slater mechanism) near the SU(3) point but originate from the gain in kinetic energy (or Mott mechanism) when the interaction anisotropy is strong. The staggered orders near the SU(3) point disappear when the next-nearest-neighbor hopping parameters are introduced, indicating that these orders are fragile, protected only by the Fermi surface nesting.

  7. Interaction induced staggered spin-orbit order in two-dimensional electron gas

    SciTech Connect

    Das, Tanmoy

    2012-06-05

    Decoupling spin and charge transports in solids is among the many prerequisites for realizing spin electronics, spin caloritronics, and spin-Hall effect. Beyond the conventional method of generating and manipulating spin current via magnetic knob, recent advances have expanded the possibility to optical and electrical method which are controllable both internally and externally. Yet, due to the inevitable presence of charge excitations and electrical polarizibility in these methods, the separation between spin and charge degrees of freedom of electrons remains a challenge. Here we propose and formulate an interaction induced staggered spin-orbit order as a new emergent phase of matter. We show that when some form of inherent spin-splitting via Rashba-type spin-orbit coupling renders two helical Fermi surfaces to become significantly nested, a Fermi surface instability arises. To lift this degeneracy, a spontaneous symmetry breaking spin-orbit density wave develops, causing a surprisingly large quasiparticle gapping with chiral electronic states, with no active charge excitations. Since the staggered spin-orbit order is associated with a condensation energy, quantified by the gap value, destroying such spin-orbit interaction costs sufficiently large perturbation field or temperature or de-phasing time. BiAg2 surface state is shown to be a representative system for realizing such novel spin-orbit interaction with tunable and large strength, and the spin-splitting is decoupled from charge excitations.

  8. A modified analysis for thermal-mechanical properties of staggered structure in biomimetic materials.

    PubMed

    Jia, Yun-Fei; Xuan, Fu-Zhen; Tu, Shan-Tung

    2012-12-01

    The thermal-mechanical stress distributions and equivalent coefficient of thermal expansion (CTE) of the staggered arrangement of mineral platelets wrapped by soft matrix are analyzed, which exist in numerous natural biological and biomimetic materials. Two analytical models, 'Stress model' and 'Displacement model', were established from the ways of stress and displacement solution based on the modification of classical shear-lag model. Complementary finite element analysis (FEA) was used to verify the analytical models. Results reveal that, compared to 'Displacement model', 'Stress model' gives a better prediction of the stress distributions within the staggered structure referring to FEA. The equivalent CTE predicted by both models reach constant as the aspect ratio and volume fraction of platelets exceeding the critical values. Nevertheless, the relative error between the results from different models increases with the increase of the ratio of overlap to length of platelets. These provide a benchmark to the optimum design of micro/nano-structure in bio-inspired materials suffering to temperature fluctuation and applied loading. PMID:23158216

  9. Calculations of separated 3-D flows with a pressure-staggered Navier-Stokes equations solver

    NASA Technical Reports Server (NTRS)

    Kim, S.-W.

    1991-01-01

    A Navier-Stokes equations solver based on a pressure correction method with a pressure-staggered mesh and calculations of separated three-dimensional flows are presented. It is shown that the velocity pressure decoupling, which occurs when various pressure correction algorithms are used for pressure-staggered meshes, is caused by the ill-conditioned discrete pressure correction equation. The use of a partial differential equation for the incremental pressure eliminates the velocity pressure decoupling mechanism by itself and yields accurate numerical results. Example flows considered are a three-dimensional lid driven cavity flow and a laminar flow through a 90 degree bend square duct. For the lid driven cavity flow, the present numerical results compare more favorably with the measured data than those obtained using a formally third order accurate quadratic upwind interpolation scheme. For the curved duct flow, the present numerical method yields a grid independent solution with a very small number of grid points. The calculated velocity profiles are in good agreement with the measured data.

  10. Odd-even staggering of binding energy for nuclei in the s d shell

    NASA Astrophysics Data System (ADS)

    Fu, G. J.; Cheng, Y. Y.; Jiang, H.; Zhao, Y. M.; Arima, A.

    2016-08-01

    In this paper we study odd-even staggering phenomena of binding energy in the framework of the nuclear shell model for nuclei in the s d shell. We decompose the USDB effective interaction into the monopole interaction and multipole (residual) interactions. We extract the empirical proton-neutron interaction, the Wigner energy, and the one-neutron separation energy using calculated binding energies. The monopole interaction, which represents the spherical mean field, provides contributions to the empirical proton-neutron interaction, the symmetry energy, and the Wigner energy. It does not induce odd-even staggering of the empirical proton-neutron interaction or the one-neutron separation energy. Isovector monopole and quadrupole pairing interactions and isoscalar spin-1 pairing interactions play a key role in reproducing an additional binding energy in both even-even and odd-odd nuclei. The Wigner energy coefficients are sensitive to residual two-body interactions. The nuclear shell structure has a strong influence on the evolution of the one-neutron separation energy, but not on empirical proton-neutron interactions. The so-called three-point formula is a good probe of the shell structure.

  11. Heat transfer characteristics of staggered wing-shaped tubes bundle at different angles of attack

    NASA Astrophysics Data System (ADS)

    Sayed Ahmed, Sayed Ahmed E.; Ibrahiem, Emad Z.; Mesalhy, Osama M.; Abdelatief, Mohamed A.

    2014-08-01

    An experimental and numerical study has been conducted to clarify heat transfer characteristics and effectiveness of a cross-flow heat exchanger employing staggered wing-shaped tubes at different angels of attack. The water-side Rew and the air-side Rea were at 5 × 102 and at from 1.8 × 103 to 9.7 × 103, respectively. The tubes arrangements were employed with various angles of attack θ1,2,3 from 0° to 330° at the considered Rea range. Correlation of Nu, St, as well as the heat transfer per unit pumping power (ɛ) in terms of Rea and design parameters for the studied bundle were presented. The temperature fields around the staggered wing-shaped tubes bundle were predicted by using commercial CFD FLUENT 6.3.26 software package. Results indicated that the heat transfer increased with the angle of attack in the range from 0° to 45°, while the opposite was true for angles of attack from 135° to 180°. The best thermal performance and hence the efficiency η of studied bundle occurred at the lowest Rea and/or zero angle of attack. Comparisons between the experimental and numerical results of the present study and those, previously, obtained for similar available studies showed good agreements.

  12. Staggered scheduling of sensor estimation and fusion for tracking over long-haul links

    DOE PAGES

    Liu, Qiang; Rao, Nageswara S. V.; Wang, Xin

    2016-08-01

    Networked sensing can be found in a multitude of real-world applications. Here, we focus on the communication-and computation-constrained long-haul sensor networks, where sensors are remotely deployed over a vast geographical area to perform certain tasks. Of special interest is a class of such networks where sensors take measurements of one or more dynamic targets and send their state estimates to a remote fusion center via long-haul satellite links. The severe loss and delay over such links can easily reduce the amount of sensor data received by the fusion center, thereby limiting the potential information fusion gain and resulting in suboptimalmore » tracking performance. In this paper, starting with the temporal-domain staggered estimation for an individual sensor, we explore the impact of the so-called intra-state prediction and retrodiction on estimation errors. We then investigate the effect of such estimation scheduling across different sensors on the spatial-domain fusion performance, where the sensing time epochs across sensors are scheduled in an asynchronous and staggered manner. In particular, the impact of communication delay and loss as well as sensor bias on such scheduling is explored by means of numerical and simulation studies that demonstrate the validity of our analysis.« less

  13. Maximum group velocity in a one-dimensional model with a sinusoidally varying staggered potential

    NASA Astrophysics Data System (ADS)

    Nag, Tanay; Sen, Diptiman; Dutta, Amit

    2015-06-01

    We use Floquet theory to study the maximum value of the stroboscopic group velocity in a one-dimensional tight-binding model subjected to an on-site staggered potential varying sinusoidally in time. The results obtained by numerically diagonalizing the Floquet operator are analyzed using a variety of analytical schemes. In the low-frequency limit we use adiabatic theory, while in the high-frequency limit the Magnus expansion of the Floquet Hamiltonian turns out to be appropriate. When the magnitude of the staggered potential is much greater or much less than the hopping, we use degenerate Floquet perturbation theory; we find that dynamical localization occurs in the former case when the maximum group velocity vanishes. Finally, starting from an "engineered" initial state where the particles (taken to be hard-core bosons) are localized in one part of the chain, we demonstrate that the existence of a maximum stroboscopic group velocity manifests in a light-cone-like spreading of the particles in real space.

  14. Computational imaging from non-uniform degradation of staggered TDI thermal infrared imager.

    PubMed

    Sun, Tao; Liu, Jian Guo; Shi, Yan; Chen, Wangli; Qin, Qianqing; Zhang, Zijian

    2015-09-21

    For the Time Delay Integration (TDI) staggered line-scanning thermal infrared imager, a Computational Imaging (CI) approach is developed to achieve higher spatial resolution images. After a thorough analysis of the causes of non-uniform image displacement and degradation for multi-channel staggered TDI arrays, the study aims to approach one-dimensional (1D) sub-pixel displacement estimation and superposition of images from time-division multiplexing scanning lines. Under the assumption that a thermal image is 2D piecewise C(2) smooth, a sparse-and-smooth deconvolution algorithm with L1-norm regularization terms combining the first and second order derivative operators is proposed to restore high frequency components and to suppress aliasing simultaneously. It is theoretically and experimentally demonstrated, with simulation and airborne thermal infrared images, that this is a state-of-the-art practical CI method to reconstruct clear images with higher frequency components from raw thermal images that are subject to instantaneous distortion and blurring. PMID:26406660

  15. Parametric modeling and stagger angle optimization of an axial flow fan

    NASA Astrophysics Data System (ADS)

    Li, M. X.; Zhang, C. H.; Liu, Y.; Y Zheng, S.

    2013-12-01

    Axial flow fans are widely used in every field of social production. Improving their efficiency is a sustained and urgent demand of domestic industry. The optimization of stagger angle is an important method to improve fan performance. Parametric modeling and calculation process automation are realized in this paper to improve optimization efficiency. Geometric modeling and mesh division are parameterized based on GAMBIT. Parameter setting and flow field calculation are completed in the batch mode of FLUENT. A control program is developed in Visual C++ to dominate the data exchange of mentioned software. It also extracts calculation results for optimization algorithm module (provided by Matlab) to generate directive optimization control parameters, which as feedback are transferred upwards to modeling module. The center line of the blade airfoil, based on CLARK y profile, is constructed by non-constant circulation and triangle discharge method. Stagger angles of six airfoil sections are optimized, to reduce the influence of inlet shock loss as well as gas leak in blade tip clearance and hub resistance at blade root. Finally an optimal solution is obtained, which meets the total pressure requirement under given conditions and improves total pressure efficiency by about 6%.

  16. CaFeAs2: A staggered intercalation of quantum spin Hall and high-temperature superconductivity

    NASA Astrophysics Data System (ADS)

    Wu, Xianxin; Qin, Shengshan; Liang, Yi; Le, Congcong; Fan, Heng; Hu, Jiangping

    2015-02-01

    We predict that CaFeAs2, a newly discovered iron-based high-temperature (Tc) superconductor, is a staggered intercalation compound that integrates topological quantum spin Hall (QSH) and superconductivity (SC). CaFeAs2 has a structure with staggered CaAs and FeAs layers. While the FeAs layers are known to be responsible for high Tc superconductivity, we show that with spin orbital coupling each CaAs layer is a Z2 topologically nontrivial two-dimensional QSH insulator and the bulk is a three-dimensional weak topological insulator. In the superconducting state, the edge states in the CaAs layer are natural one-dimensional topological superconductors. The staggered intercalation of QSH and SC provides us a unique opportunity to realize and explore physics, such as Majorana modes and Majorana fermion chains.

  17. Note: Double-beveled multilayer stagger-split die for a large volume high-pressure apparatus.

    PubMed

    Wang, Bolong; Li, Mingzhe; Yang, Yunfei; Liu, Zhiwei

    2015-08-01

    A high-pressure device with a large cavity was investigated using finite-element analysis. This device is called a double-beveled multilayer stagger-split die, and consists of two supported rings and a multilayer divided body assemblage. Each divided cylinder body has two bevels in the pressurized surface. We simulated the pressure capacity of this device according to different failure criteria. The results were compared with those of a multilayer stagger-split die and belt type die. The bearing capacity of the double-beveled multilayer stagger-split die was more than 7.3 GPa. A group of comparative experiments were conducted to validate the simulated results, and the experimental results show the actual pressure capacity was higher than the simulation.

  18. My Half Hour with Einstein

    NASA Astrophysics Data System (ADS)

    Romer, Robert H.

    2005-03-01

    "So you're studying at Princeton. Would you like to meet Einstein?" That question, during a brief two-body collision at a cocktail party, a collision that was over before I could think of an appropriate response, led—over a year later—to one of the more memorable half hours of my life. It was an elastic collision, we drifted apart, and I thought it had simply been a casual remark until a few days later when the mail brought me a carbon copy [sic] of a letter (dated "25.XII.52") from the speaker, Dr. Tilly Edinger, to Albert Einstein. Accompanying the letter to Einstein was a card that Dr. Edinger advised me to send around to Einstein's home on Mercer Street to request a meeting. (What is perhaps most truly astonishing in connection with this event is that not only do I still have that carbon copy—and the eventual letter from Mercer Street that invited me to Einstein's home—but that I was able to find both documents in my attic!)

  19. 24-Hour Relativistic Bit Commitment

    NASA Astrophysics Data System (ADS)

    Verbanis, Ephanielle; Martin, Anthony; Houlmann, Raphaël; Boso, Gianluca; Bussières, Félix; Zbinden, Hugo

    2016-09-01

    Bit commitment is a fundamental cryptographic primitive in which a party wishes to commit a secret bit to another party. Perfect security between mistrustful parties is unfortunately impossible to achieve through the asynchronous exchange of classical and quantum messages. Perfect security can nonetheless be achieved if each party splits into two agents exchanging classical information at times and locations satisfying strict relativistic constraints. A relativistic multiround protocol to achieve this was previously proposed and used to implement a 2-millisecond commitment time. Much longer durations were initially thought to be insecure, but recent theoretical progress showed that this is not so. In this Letter, we report on the implementation of a 24-hour bit commitment solely based on timed high-speed optical communication and fast data processing, with all agents located within the city of Geneva. This duration is more than 6 orders of magnitude longer than before, and we argue that it could be extended to one year and allow much more flexibility on the locations of the agents. Our implementation offers a practical and viable solution for use in applications such as digital signatures, secure voting and honesty-preserving auctions.

  20. Renormalization-group approach to quantum Fisher information in an XY model with staggered Dzyaloshinskii-Moriya interaction

    PubMed Central

    Liu, X. M.; Cheng, W. W.; Liu, J. -M.

    2016-01-01

    We investigate the quantum Fisher information and quantum phase transitions of an XY spin chain with staggered Dzyaloshinskii-Moriya interaction using the quantum renormalization-group method. The quantum Fisher information, its first-derivatives, and the finite-size scaling behaviors are rigorously calculated respectively. The singularity of the derivatives at the phase transition point as a function of lattice size is carefully discussed and it is revealed that the scaling exponent for quantum Fisher information at the critical point can be used to describe the correlation length of this model, addressing the substantial role of staggered Dzyaloshinskii-Moriya interaction in modulating quantum phase transitions. PMID:26780973

  1. Implementation of An Implicit Unsplit Staggered Mesh MHD Solver in FLASH

    NASA Astrophysics Data System (ADS)

    Xia, G.; Lee, D.

    2010-11-01

    FLASH is a publicly available community code designed to solve highly compressible multi-physics reactive flows. We have been adding capabilities to FLASH to make it an open science code for the academic HEDP community. A key need is to provide a computationally efficient time-stepping integration method that overcomes the stiffness that arises in the equations describing a physical problem when there are disparate time scales. To address this problem, we are developing a fully implicit solver based on a Jacobian-Free Newton-Krylov implicit formulation. The method has been integrated into a robust, efficient, and high-order accurate Unsplit Staggered Mesh MHD (USM) solver. We are also integrating this solver into an anisotropic Spitzer-Braginskii conductivity model to treat thermal heat conduction along magnetic field lines, and into a treatment of the Biermann Battery effect that accounts for spontaneous generation of magnetic fields in the presence of non-parallel temperature and density gradients.

  2. B and D meson decay constants from 2+1 flavor improved staggered simulations

    SciTech Connect

    Neil, E.T.; Bailey, Jon A.; Bazavov, A.; Bernard, C.; Bouchard, C.M.; DeTar, C.; Di Pierro, M.; El-Khadra, A.X.; Evans, R.T.; Freeland, E.; Gamiz, E.

    2011-12-01

    We give an update on simulation results for the decay constants f{sub B}; f{sub B{sub s}}, f{sub D} and f{sub D{sub s}}. These decay constants are important for precision tests of the standard model, in particular entering as inputs to the global CKM unitarity triangle fit. The results presented here make use of the MILC (2+1)-flavor asqtad ensembles, with heavy quarks incorporated using the clover action with the Fermilab method. Partially quenched, staggered chiral perturbation theory is used to extract the decay constants at the physical point. In addition, we give error projections for a new analysis in progress, based on an extended data set.

  3. Phase substitution of spare converter for a failed one of parallel phase staggered converters

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.; Wester, G. W. (Inventor)

    1977-01-01

    Failure detection and substitution of a spare module is provided in a system having a plurality of phase staggered modules connected in parallel to deliver regulated voltage from an unregulated source. Phase control signals applied to the active converter modules are applied to the spare module through NOR gates associated with and disabled by the power output of respective modules such that failure of any one enables its phase control signal to be applied to the spare module, thus controlling the spare module to operate in the phase position of the failed module. A NAND gate detects when any one active module fails and enables a gate in the spare module, thus activating the spare module.

  4. Direct numerical simulation of transitional flow in a staggered tube bundle

    NASA Astrophysics Data System (ADS)

    Linton, D.; Thornber, B.

    2016-02-01

    A series of Direct Numerical Simulations (DNS) of the flow through a staggered tube bundle has been performed over the range 1030 ≤ Rem ≤ 5572 to capture the flow transition that occurs at the matrix transition point of Rem ≈ 3000. The matrix transition is the point at which a second frequency becomes prominent in tube bundles. To date, this is the highest published Reynolds number at which a DNS has been performed on cross-flow over a tube bundle. This study describes the flow behaviour in terms of: the mean flow field, Strouhal numbers, vortex shedding, 3-D flow features, and turbulence properties. These results support the hypothesis that the transition in the vortex shedding behaviour at Rem ≈ 3000 is similar to that which occurs in single cylinder flow at the equivalent Reynolds number. The visualisations presented also demonstrate the nature of the shedding mechanisms before and after the matrix transition point.

  5. Robust picosecond writing of a layered antiferromagnet by staggered spin-orbit fields

    NASA Astrophysics Data System (ADS)

    Roy, P. E.; Otxoa, R. M.; Wunderlich, J.

    2016-07-01

    Ultrafast electrical switching by current-induced staggered spin-orbit fields, with minimal risk of overshoot is shown in layered easy-plane antiferromagnets with basal-plane anisotropies. Reliable switching is due to the fieldlike torque, relaxing stringent requirements with respect to precision in the duration of the excitation pulse. Focus is put on a system with weak planar biaxial anisotropy. We investigate the switching as a function of the spin-orbit field strength, pulse duration, rise and fall times, and damping using atomistic spin dynamics simulations and an effective equation for the antiferromagnetic order parameter. The critical spin-orbit field strength required for switching a biaxial system is determined, and we show that writing is possible at feasible current magnitudes. Finally, we discuss switching of systems exhibiting a dominant uniaxial basal-plane anisotropy.

  6. Isospin Dependence in the Odd-Even Staggering of Nuclear Binding Energies

    SciTech Connect

    Litvinov, Yu.A.; Geissel, H.; Buervenich, T.J.; Novikov, Yu.N.; Patyk, Z.; Scheidenberger, C.; Attallah, F.; Beckert, K.; Bosch, F.; Franzke, B.; Klepper, O.; Kluge, H.-J.; Kozhuharov, C.; Muenzenberg, G.; Nolden, F.; Radon, T.; Steck, M.; Typel, S.; Audi, G.; Falch, M.

    2005-07-22

    The FRS-ESR facility at GSI provides unique conditions for precision measurements of large areas on the nuclear mass surface in a single experiment. Values for masses of 604 neutron-deficient nuclides (30{<=}Z{<=}92) were obtained with a typical uncertainty of 30 {mu}u. The masses of 114 nuclides were determined for the first time. The odd-even staggering (OES) of nuclear masses was systematically investigated for isotopic chains between the proton shell closures at Z=50 and Z=82. The results were compared with predictions of modern nuclear models. The comparison revealed that the measured trend of OES is not reproduced by the theories fitted to masses only. The spectral pairing gaps extracted from models adjusted to both masses, and density related observables of nuclei agree better with the experimental data.

  7. A free surface capturing discretization for the staggered grid finite difference scheme

    NASA Astrophysics Data System (ADS)

    Duretz, T.; May, D. A.; Yamato, P.

    2016-03-01

    The coupling that exists between surface processes and deformation within both the shallow crust and the deeper mantle-lithosphere has stimulated the development of computational geodynamic models that incorporate a free surface boundary condition. We introduce a treatment of this boundary condition that is suitable for staggered grid, finite difference schemes employing a structured Eulerian mesh. Our interface capturing treatment discretizes the free surface boundary condition via an interface that conforms with the edges of control volumes (e.g. a `staircase' representation) and requires only local stencil modifications to be performed. Comparisons with analytic solutions verify that the method is first-order accurate. Additional intermodel comparisons are performed between known reference models to further validate our free surface approximation. Lastly, we demonstrate the applicability of a multigrid solver to our free surface methodology and demonstrate that the local stencil modifications do not strongly influence the convergence of the iterative solver.

  8. Odd-Even Mass Staggering Described by Relativistic Hartree-Fock Theory

    NASA Astrophysics Data System (ADS)

    Wang, Long Jun; Long, Wen Hui

    2013-11-01

    The neutron and proton odd-even mass staggering (OES) are systematically studied within the density-dependent relativistic Hartree-Fock-Bogoliubov (DDRHFB) theory and the density-dependent relativistic Hartree-Bogoliubov (DDRHB) theory. In terms of the finite-range Gogny D1S as the pairing force, both DDRHFB and DDRHB theories can well reproduce the experimental OES, including C, O, Ca, Ni, Zr, Sn, Ce, Gd and Pb isotopes, and N = 50 and 82 isotones. In addition, the optimizations on the pairing force with the prefix factors bring systematical improvements on the OES for the light and heavy nuclei. It is also found that the pairing effects are essentially related with the appropriate description of the nuclear structures, in which the ρ-tensor correlations play an important role.

  9. Axially staggered seed-blanket reactor-fuel-module construction. [LWBR

    DOEpatents

    Cowell, G.K.; DiGuiseppe, C.P.

    1982-10-28

    A heterogeneous nuclear reactor of the seed-blanket type is provided wherein the fissile (seed) and fertile (blanket) nuclear fuels are segregated axially within each fuel element such that fissile and fertile regions occur in an alternating pattern along the length of the fuel element. Further, different axial stacking patterns are used for the fuel elements of at least two module types such that when modules of different types are positioned adjacent to one another, the fertile regions of the modules are offset or staggered. Thus, when a module of one type is surrounded by modules of the second type the fertile regions thereof will be surrounded on all sides by fissile material. This provides enhanced neutron communication both radially and axially, thereby resulting in greater power oscillation stability than other axial arrangements.

  10. A staggered coupling strategy for the finite element analysis of warm deep drawing process

    NASA Astrophysics Data System (ADS)

    Martins, J. M. P.; Cunha, P. M.; Neto, D. M.; Alves, J. L.; Oliveira, M. C.; Laurent, H.; Menezes, L. F.

    2016-08-01

    The thermomechanical finite element analysis of warm forming processes enables an improved comprehension of the process parameters affecting the material formability. However, the thermal and mechanical coupling problem is still a challenge from the computational standpoint. A staggered strategy for the thermomechanical coupling problem is presented in this study, which is based on an isothermal split approach and allows the treatment of the two problems separately. The exchange of information between the mechanical and the thermal problem is performed to achieve a compromise between computational cost and accuracy. The proposed algorithm was implemented in DD3IMP in-house finite element code. Its performance is analysed and compared with a classical strategy commonly employed for solving thermomechanical problems.

  11. Spectrum of the Dirac operator and multigrid algorithm with dynamical staggered fermions

    SciTech Connect

    Kalkreuter, T. Fachbereich Physik , Humboldt-Universitaet, Invalidenstrasse 110, D-10099 Berlin )

    1995-02-01

    Complete spectra of the staggered Dirac operator [ital ];sD are determined in quenched four-dimensional SU(2) gauge fields, and also in the presence of dynamical fermions. Periodic as well as antiperiodic boundary conditions are used. An attempt is made to relate the performance of multigrid (MG) and conjugate gradient (CG) algorithms for propagators with the distribution of the eigenvalues of [ital ];sD. The convergence of the CG algorithm is determined only by the condition number [kappa] and by the lattice size. Since [kappa]'s do not vary significantly when quarks become dynamic, CG convergence in unquenched fields can be predicted from quenched simulations. On the other hand, MG convergence is not affected by [kappa] but depends on the spectrum in a more subtle way.

  12. Staggered fermions and chiral symmetry breaking in transverse lattice regulated QED

    SciTech Connect

    Griffin, P.A.

    1992-07-01

    Staggered fermions are constructed for the transverse lattice regularization scheme. The weak perturbation theory of transverse lattice non-compact QED is developed in light-cone gauge, and we argue that for fixed lattice spacing this theory is ultraviolet finite, order by order in perturbation theory. However, by calculating the anomalous scaling dimension of the link fields, we find that the interaction Hamiltonian becomes non-renormalizable for g{sup 2}(a) > 4{pi}, where g(a) is the bare (lattice) QED coupling constant. We conjecture that this is the critical point of the chiral symmetry breaking phase transition in QED. Non-perturbative chiral symmetry breaking is then studied in the strong coupling limit. The discrete remnant of chiral symmetry that remains on the lattice is spontaneously broken, and the ground state to lowest order in the strong coupling expansion corresponds to the classical ground state of the two-dimensional spin one-half Heisenberg antiferromagnet.

  13. The Student Credit Hour: Counting What Counts

    ERIC Educational Resources Information Center

    Wellman, Jane

    2005-01-01

    The article discusses the student credit hour (SCH). The author begins with a rethinking of the basic unit of measurement in American higher education--the SCH. The credit hour was developed at the turn of the 20th century as a measure of student time in the classroom: one hour per week in class for one semester equalled one SCH. The credit hour…

  14. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 9 2013-10-01 2013-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  15. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 9 2014-10-01 2014-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  16. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  17. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  18. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 9 2012-10-01 2012-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  19. a Numerical Study of Unsteady Fluid Flow in In-Line and Staggered Tube Banks

    NASA Astrophysics Data System (ADS)

    Beale, S. B.; Spalding, D. B.

    1999-08-01

    This paper is concerned with the results of numerical calculations for transient flow in in-line-square and rotated-square tube banks with a pitch-to-diameter ratio of 2:1, in the Reynolds number range of 30-3000. Transient-periodic behaviour is induced by the consideration of two or more modules, with a sinusoidal span-wise perturbation being applied in the upstream module. There is a triode-like effect, whereby the downstream response to the stimulus is amplified, and there is a net gain in the crosswise flow component. When an appropriate feedback mechanism is provided, a stable transient behaviour is obtained, with alternate vortices being shed from each cylinder. Flow visualization studies of the results of the calculations are presented together with quantitative details of pressure drop, lift, drag and heat transfer. For the staggered bank, a wake-switching or Coanda effect was observed as the serpentine-shaped wake attached to alternate sides of the downstream cylinder. The induced response is independent of the amplitude and frequency of the applied disturbance, including the case of spontaneous behaviour with no excitation mechanism. For the in-line case where each cylinder is in the shadow of the previous one, the motion is less pronounced; however, a shear-layer instability associated with the alternating spin of shed vortices was observed. In this case, the response was found to be somewhat dependent on the frequency of the applied disturbance, and a transient motion could not be induced spontaneously in the absence of an explicit feedback mechanism. Calculated Strouhal numbers were in fair agreement with experimental data: for the staggered geometry, they had values of between 0.26 and 0.35, or from -21 to +6% higher than measured values, while for the in-line geometry, the Strouhal numbers ranged between 0.09 and 0.12, or about 20-40% lower than experimental values.

  20. Investigation of analog/RF performance of staggered heterojunctions based nanowire tunneling field-effect transistors

    NASA Astrophysics Data System (ADS)

    Chakraborty, Avik; Sarkar, Angsuman

    2015-04-01

    In this paper, the analog/RF performance of an III-V semiconductor based staggered hetero-tunnel-junction (HETJ) n-type nanowire (NW) tunneling FET (n-TFET) is investigated, for the first time. The device performance figure-of-merits governing the analog/RF performance such as transconductance (gm), transconductance-to-drive current ratio (gm/IDS), output resistance (Rout), intrinsic gain and unity-gain cutoff frequency (fT) have been studied. The analog/RF performance parameters is compared between HETJ NW TFET and a homojunction (HJ) NW n-type TFET of similar dimensions. In addition to enhanced ION and subthreshold swing, a significant improvement in the analog/RF performance parameters obtained by the HETJ n-TFET over HJ counterpart for use in analog/mixed signal System-on-Chip (SoC) applications is reported. Moreover, the analog/RF performance parameters of a III-V based staggered HETJ NW TFET is also compared with a heterojunction (HETJ) NW n-type MOSFET having same material as HETJ n-TFET and equal dimension in order to provide a systematic comparison between HETJ-TFET and HETJ-MOSFET for use in analog/mixed-signal applications. The results reveal that HETJ n-TFET provides higher Rout and hence, a higher intrinsic gain, an improved gm/IDS ratio, and reasonable fT at lower values of gate-overdrive voltage as compared to the HETJ NW n-MOSFET.

  1. BK using HYP-smeared staggered fermions in Nf = 2 + 1 unquenched QCD

    SciTech Connect

    Jung, C.; Bae, T.; Jang, Y-C.; Kim, H-J.; Kim, J.; Kim, K; Lee, W.; Sharpe, S.; Yoon, B.

    2010-12-20

    We present results for the kaon mixing parameter B{sub K} calculated using HYP (hypercubic fat link)-smeared improved staggered fermions on the asqtad lattices generated by the MILC collaboration. We use three lattice spacings (a{approx} 0.12, 0.09 and 0.06 fm), ten different valence-quark masses (m {approx} m{sub s}/10-m{sub s}), and several light sea-quark masses in order to control the continuum and chiral extrapolations. We derive the next-to-leading order staggered chiral perturbation theory (SChPT) results necessary to fit our data, and use these results to do extrapolations based both on SU(2) and SU(3) SChPT. The SU(2) fitting is particularly straightforward because parameters related to taste breaking and matching errors appear only at next-to-next-to-leading order. We match to the continuum renormalization scheme [naive dimensional regularization (NDR)] using one-loop perturbation theory. Our final result is from the SU(2) analysis, with the SU(3) result providing a (less accurate) cross check. We find B{sub K}(NDR, {mu} = 2 GeV) = 0.529 {+-} 0.009 {+-} 0.032 and B{sub K} = B{sub K}(RGI) = 0.724 {+-} 0.012 {+-} 0.043, where the first error is statistical and the second systematic. The error is dominated by the truncation error in the matching factor. Our results are consistent with those obtained using valence domain-wall fermions on lattices generated with asqtad or domain-wall sea quarks.

  2. Stabilisation patterns of hourly urban sound levels.

    PubMed

    Prieto Gajardo, Carlos; Barrigón Morillas, Juan Miguel

    2015-01-01

    In this paper, the stabilisation times for all 24 h of the day are analysed for 12 measurement stations located in the Spanish town of Malaga and throughout 5 years (2007-2011) of sampling environmental noise levels. For the results to be generalised to sound level measurements made in other streets or cities where there have been no long-term measurements, this study was developed for different road types and urban shapes. This distinction was made according to the types of roads indicated in other studies in which a statistically significant relationship was found between noise levels and the road type. The final objective of the study is to determine the capacity to estimate and approximate the real equivalent hourly noise level (L Aeq,1h) from the integration of a number of consecutive minutes (short-term measurements) less than 60 (L Aeq,1h ≈ L Aeq,T being T ≤ 60 min). Clearly, this strategy would save time and resources by making measurements of reduced duration. In summary and according to this analysis, a short-time measurement of 15 min is adequate to work with 90% confidence levels and errors of ±2 dB, with 80% confidence levels and errors of ±1 dB, and 50% confidence levels and errors of ±0.5 dB. However, it is necessary to consider the measurement hour period to achieve these levels of confidence due to the high variability throughout the day. PMID:25407987

  3. Resident duty hours around the globe: where are we now?

    PubMed

    Temple, John

    2014-01-01

    Safe and appropriate health care, especially in urgent or emergency situations, is the expectation of the public throughout the developed world. Achieving this goal requires appropriate levels of medical and other staff, appropriate training, and sensible working hours. Too often the brunt of such care, especially in out-of-hours situations, is borne by medical residents, who--to make matters worse--are frequently poorly supervised by more senior and experienced staff. Many jurisdictions have been alerted to this problem and are striving to correct it. However, the variation in attempts to restrict the actual hours worked by residents to "safe" levels is enormous, and all too often there is no consensus as to what should be put in place to achieve safe patient care. This paper sets out the current position for Europe, North America, and Australia. PMID:25559277

  4. Residency Training at a Crossroads: Duty Hour Standards 2010

    PubMed Central

    Volpp, Kevin G.; Friedman, William; Romano, Patrick S.; Rosen, Amy; Silber, Jeffrey H.

    2012-01-01

    In 2003, the Accreditation Council for Graduate Medical Education (ACMGE) implemented a single duty hour standard nationwide. The evidence to date suggests that this neither improved nor worsened patient outcomes. In June 2010, the ACGME proposed a new set of duty hour standards for implementation in July 2011. The main disadvantage of this approach is that we will not be able to determine whether different standards would have worked better to reduce resident fatigue while improving patient safety. There are many unanswered questions as to how to design duty hour standards but relatively little evidence; in addition, the same approach may not work in all specialties and all hospitals. A more flexible, dynamic policy that emphasizes ongoing testing and evaluation would be more likely to achieve improvements in clinical and educational outcomes. PMID:20956679

  5. A new 19-metal-atom cluster [(Me2PhP)10Au12Ag7(NO3)9] with a nearly staggered-staggered M5 ring configuration.

    PubMed

    Nunokawa, Keiko; Ito, Mitsuhiro; Sunahara, Tetsuya; Onaka, Satoru; Ozeki, Tomoji; Chiba, Hirokazu; Funahashi, Yasuhiro; Masuda, Hideki; Yonezawa, Tetsu; Nishihara, Hiroshi; Nakamoto, Masami; Yamamoto, Mari

    2005-08-21

    New mixed metal clusters with M19 metal frameworks have been synthesized by NaBH4 reduction of Au(NO3)(PMe2Ph) together with AgNO3 in ethanol. Single crystal X-ray diffraction has revealed Au12Ag7 and Au17Ag2 metal skeletons for these clusters, which are best described in terms of bicapped pentagonal antiprismatic cages with a staggered-staggered M(5) ring configuration. These clusters connect the missing link between M13 icosahedral and M25 biicosahedral clusters providing a view of the cluster growth process. A TEM image of this cluster has been observed, which has clearly demonstrated single-sized nano-particles of less than 1.0 nm.

  6. A solution accurate, efficient and stable unsplit staggered mesh scheme for three dimensional magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Lee, Dongwook

    2013-06-01

    In this paper, we extend the unsplit staggered mesh scheme (USM) for 2D magnetohydrodynamics (MHD) [D. Lee, A.E. Deane, An unsplit staggered mesh scheme for multidimensional magnetohydrodynamics, J. Comput. Phys. 228 (2009) 952-975] to a full 3D MHD scheme. The scheme is a finite-volume Godunov method consisting of a constrained transport (CT) method and an efficient and accurate single-step, directionally unsplit multidimensional data reconstruction-evolution algorithm, which extends Colella's original 2D corner transport upwind (CTU) method [P. Colella, Multidimensional upwind methods for hyperbolic conservation laws, J. Comput. Phys. 87 (1990) 446-466]. We present two types of data reconstruction-evolution algorithms for 3D: (1) a reduced CTU scheme and (2) a full CTU scheme. The reduced 3D CTU scheme is a variant of a simple 3D extension of Collela's 2D CTU method and is considered as a direct extension from the 2D USM scheme. The full 3D CTU scheme is our primary 3D solver which includes all multidimensional cross-derivative terms for stability. The latter method is logically analogous to the 3D unsplit CTU method by Saltzman [J. Saltzman, An unsplit 3D upwind method for hyperbolic conservation laws, J. Comput. Phys. 115 (1994) 153-168]. The major novelties in our algorithms are twofold. First, we extend the reduced CTU scheme to the full CTU scheme which is able to run with CFL numbers close to unity. Both methods utilize the transverse update technique developed in the 2D USM algorithm to account for transverse fluxes without solving intermediate Riemann problems, which in turn gives cost-effective 3D methods by reducing the total number of Riemann solves. The proposed algorithms are simple and efficient especially when including multidimensional MHD terms that maintain in-plane magnetic field dynamics. Second, we introduce a new CT scheme that makes use of proper upwind information in taking averages of electric fields. Our 3D USM schemes can be easily

  7. 19 CFR 101.6 - Hours of business.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... interferes with the performance of his work in a CBP office. (e) Services performed outside a CBP office. CBP... recurring need for CBP services outside the hours prescribed in paragraphs (a) through (e) of this section... falls on Sunday, the day immediately following such Sunday will be observed. (5 U.S.C. 6103(b)(1));...

  8. 19 CFR 101.6 - Hours of business.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... interferes with the performance of his work in a CBP office. (e) Services performed outside a CBP office. CBP... recurring need for CBP services outside the hours prescribed in paragraphs (a) through (e) of this section... falls on Sunday, the day immediately following such Sunday will be observed. (5 U.S.C. 6103(b)(1));...

  9. 19 CFR 101.6 - Hours of business.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... interferes with the performance of his work in a CBP office. (e) Services performed outside a CBP office. CBP... recurring need for CBP services outside the hours prescribed in paragraphs (a) through (e) of this section... falls on Sunday, the day immediately following such Sunday will be observed. (5 U.S.C. 6103(b)(1));...

  10. 19 CFR 101.6 - Hours of business.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... interferes with the performance of his work in a CBP office. (e) Services performed outside a CBP office. CBP... recurring need for CBP services outside the hours prescribed in paragraphs (a) through (e) of this section... falls on Sunday, the day immediately following such Sunday will be observed. (5 U.S.C. 6103(b)(1));...

  11. A Study of a Two Hour Time Block in Industrial Education. Final Report.

    ERIC Educational Resources Information Center

    Gearhart, Robert E.; McMillen, Stephen

    Hypotheses of a study of two-hour as opposed to three-hour training blocks for industrial vocational education students were as follows: (1) Achievement of students in a two-hour block for three years will be equal to that of students in a three-hour block for two years, (2) student attitudes toward themselves, school, and the world of work will…

  12. 20 CFR 801.304 - Business hours.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Business hours. 801.304 Section 801.304 Employees' Benefits BENEFITS REVIEW BOARD, DEPARTMENT OF LABOR ESTABLISHMENT AND OPERATION OF THE BOARD Action by the Board § 801.304 Business hours. The office of the Clerk of the Board at Washington,...

  13. 17 CFR 201.104 - Business hours.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Business hours. 201.104 Section 201.104 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION RULES OF PRACTICE Rules of Practice General Rules § 201.104 Business hours. The Headquarters office of the Commission,...

  14. The Credit Hour and Faculty Instructional Workload.

    ERIC Educational Resources Information Center

    Ehrlich, Thomas

    2003-01-01

    Studied the credit hour as a measure of faculty workload through interviews with administrators at several public and private colleges and universities. The credit hour metric did not appear to be stifling innovation, although at some public campuses those regulations made innovation more difficult. (SLD)

  15. The Student Credit Hour: An International Exploration.

    ERIC Educational Resources Information Center

    Wolanin, Thomas R.

    2003-01-01

    Explored if and how the credit hour is used in higher education outside of the United States, with a focus on its use in measuring student progress and attainment. The use of the credit hour in Europe, where it has fostered innovation, and in Japan, and Australia generally follows the fundamentals of the U.S. model. (SLD)

  16. The Credit Hour and Public Budgeting.

    ERIC Educational Resources Information Center

    Wellman, Jane V.

    2003-01-01

    Discusses the ways the credit hour has come to be used by public funding systems in higher education. The literature review shows that the credit hour has become a barrier to innovation and a way to create systemic inequities between institutions or sectors in resource allocation. (SLD)

  17. 14 CFR 1206.403 - Duty hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Duty hours. 1206.403 Section 1206.403 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION AVAILABILITY OF AGENCY RECORDS TO MEMBERS OF THE PUBLIC Location for Inspection and Request of Agency Records § 1206.403 Duty hours. The...

  18. 14 CFR 1206.403 - Duty hours.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Duty hours. 1206.403 Section 1206.403 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION AVAILABILITY OF AGENCY RECORDS TO MEMBERS OF THE PUBLIC Location for Inspection and Request of Agency Records § 1206.403 Duty hours. The...

  19. 20 CFR 801.304 - Business hours.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Business hours. 801.304 Section 801.304 Employees' Benefits BENEFITS REVIEW BOARD, DEPARTMENT OF LABOR ESTABLISHMENT AND OPERATION OF THE BOARD Action by the Board § 801.304 Business hours. The office of the Clerk of the Board at Washington,...

  20. 20 CFR 801.304 - Business hours.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Business hours. 801.304 Section 801.304 Employees' Benefits BENEFITS REVIEW BOARD, DEPARTMENT OF LABOR ESTABLISHMENT AND OPERATION OF THE BOARD Action by the Board § 801.304 Business hours. The office of the Clerk of the Board at Washington,...

  1. 20 CFR 801.304 - Business hours.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Business hours. 801.304 Section 801.304 Employees' Benefits BENEFITS REVIEW BOARD, DEPARTMENT OF LABOR ESTABLISHMENT AND OPERATION OF THE BOARD Action by the Board § 801.304 Business hours. The office of the Clerk of the Board at Washington,...

  2. 20 CFR 801.304 - Business hours.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Business hours. 801.304 Section 801.304 Employees' Benefits BENEFITS REVIEW BOARD, DEPARTMENT OF LABOR ESTABLISHMENT AND OPERATION OF THE BOARD Action by the Board § 801.304 Business hours. The office of the Clerk of the Board at Washington,...

  3. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  4. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  5. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  6. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  7. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  8. 24-Hour Academic Libraries: Adjusting to Change

    ERIC Educational Resources Information Center

    Bowman, Adam C.

    2013-01-01

    The purpose of this study was to explore the adaptive measures that academic libraries perform when implementing and operating a 24-hour schedule. Five in-depth interviews were conducted with current managerial-level librarians at 24-hour academic libraries. The exploratory interviews revealed similar measures for security, budgeting, employee…

  9. Competition between pairing correlations and deformation from the odd-even mass staggering of francium and radium isotopes

    NASA Astrophysics Data System (ADS)

    Kreim, S.; Beck, D.; Blaum, K.; Borgmann, Ch.; Breitenfeldt, M.; Cocolios, T. E.; Gottberg, A.; Herfurth, F.; Kowalska, M.; Litvinov, Yu. A.; Lunney, D.; Manea, V.; Mendonca, T. M.; Naimi, S.; Neidherr, D.; Rosenbusch, M.; Schweikhard, L.; Stora, Th.; Wienholtz, F.; Wolf, R. N.; Zuber, K.

    2014-08-01

    The masses of Fr222,224,226-233 and Ra233,234 have been determined with the Penning-trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN, including the previously unknown mass and half-life of Fr233. We study the evolution of the odd-even staggering of binding energies along the francium and radium isotopic chains and of its lowest-order estimator, Δ3(N). An enhancement of the staggering of Δ3(N) is observed towards neutron number N =146, which points to contributions beyond pairing correlations. These contributions are investigated in the Hartree-Fock and Hartree-Fock-Bogoliubov approaches, emphasizing the connections to the single-particle level density and nuclear deformation.

  10. Restoration of images captured by a staggered time delay and integration camera in the presence of mechanical vibrations.

    PubMed

    Hochman, Gadi; Yitzhaky, Yitzhak; Kopeika, Norman S; Lauber, Yair; Citroen, Meira; Stern, Adrian

    2004-08-01

    Staggered time delay and integration (TDI) scanning image acquisition systems are usually employed in low signal-to-noise situations such as thermal imaging. Analysis and restoration of images acquired by thermal staggered TDI sensors in the presence of mechanical vibrations that may cause space-variant image distortions (severe geometric warps and blur) are studied. The relative motion at each location in the degraded image is identified from the image when a differential technique is used. This information is then used to reconstruct the image by a technique of projection onto convex sets. The main novelty is the implementation of such methods to scanned images (columnwise). Restorations are performed with simulated and real mechanically degraded thermal images.

  11. Massive expansions of Dscam splicing diversity via staggered homologous recombination during arthropod evolution.

    PubMed

    Lee, Christopher; Kim, Namshin; Roy, Meenakshi; Graveley, Brenton R

    2010-01-01

    The arthropod Down syndrome cell adhesion molecule (Dscam) gene can generate tens of thousands of protein isoforms via combinatorial splicing of numerous alternative exons encoding immunoglobulin variable domains organized into three clusters referred to as the exon 4, 6, and 9 clusters. Dscam protein diversity is important for nervous system development and immune functions. We have performed extensive phylogenetic analyses of Dscam from 20 arthropods (each containing between 46 and 96 alternative exons) to reconstruct the detailed history of exon duplication and loss events that built this remarkable system over 450 million years of evolution. Whereas the structure of the exon 4 cluster is ancient, the exon 6 and 9 clusters have undergone massive, independent expansions in each insect lineage. An analysis of nearly 2000 duplicated exons enabled detailed reconstruction of the timing, location, and boundaries of these duplication events. These data clearly show that new Dscam exons have arisen continuously throughout arthropod evolution and that this process is still occurring in the exon 6 and 9 clusters. Recently duplicated regions display boundaries corresponding to a single exon and the adjacent intron. The boundaries, homology, location, clustering, and relative frequencies of these duplication events strongly suggest that staggered homologous recombination is the major mechanism by which new Dscam exons evolve. These data provide a remarkably detailed picture of how complex gene structure evolves and reveal the molecular mechanism behind this process.

  12. Progress in development of HEDP capabilities in FLASH's Unsplit Staggered Mesh MHD solver

    NASA Astrophysics Data System (ADS)

    Lee, D.; Xia, G.; Daley, C.; Dubey, A.; Gopal, S.; Graziani, C.; Lamb, D.; Weide, K.

    2011-11-01

    FLASH is a publicly available astrophysical community code designed to solve highly compressible multi-physics reactive flows. We are adding capabilities to FLASH that will make it an open science code for the academic HEDP community. Among many important numerical requirements, we consider the following features to be important components necessary to meet our goals for FLASH as an HEDP open toolset. First, we are developing computationally efficient time-stepping integration methods that overcome the stiffness that arises in the equations describing a physical problem when there are disparate time scales. To this end, we are adding two different time-stepping schemes to FLASH that relax the time step limit when diffusive effects are present: an explicit super-time-stepping algorithm (Alexiades et al. in Com. Num. Mech. Eng. 12:31-42, 1996) and a Jacobian-Free Newton-Krylov implicit formulation. These two methods will be integrated into a robust, efficient, and high-order accurate Unsplit Staggered Mesh MHD (USM) solver (Lee and Deane in J. Comput. Phys. 227, 2009). Second, we have implemented an anisotropic Spitzer-Braginskii conductivity model to treat thermal heat conduction along magnetic field lines. Finally, we are implementing the Biermann Battery term to account for spontaneous generation of magnetic fields in the presence of non-parallel temperature and density gradients.

  13. Relaxing the closure assumption in single-season occupancy models: staggered arrival and departure times

    USGS Publications Warehouse

    Kendall, William L.; Hines, James E.; Nichols, James D.; Grant, Evan H. Campbell

    2013-01-01

    Occupancy statistical models that account for imperfect detection have proved very useful in several areas of ecology, including species distribution and spatial dynamics, disease ecology, and ecological responses to climate change. These models are based on the collection of multiple samples at each of a number of sites within a given season, during which it is assumed the species is either absent or present and available for detection while each sample is taken. However, for some species, individuals are only present or available for detection seasonally. We present a statistical model that relaxes the closure assumption within a season by permitting staggered entry and exit times for the species of interest at each site. Based on simulation, our open model eliminates bias in occupancy estimators and in some cases increases precision. The power to detect the violation of closure is high if detection probability is reasonably high. In addition to providing more robust estimation of occupancy, this model permits comparison of phenology across sites, species, or years, by modeling variation in arrival or departure probabilities. In a comparison of four species of amphibians in Maryland we found that two toad species arrived at breeding sites later in the season than a salamander and frog species, and departed from sites earlier.

  14. The molecular mechanism of "ryegrass staggers," a neurological disorder of K+ channels.

    PubMed

    Imlach, Wendy L; Finch, Sarah C; Dunlop, James; Meredith, Andrea L; Aldrich, Richard W; Dalziel, Julie E

    2008-12-01

    "Ryegrass staggers" is a neurological condition of unknown mechanism that impairs motor function in livestock. It is caused by infection of perennial ryegrass pastures by an endophytic fungus that produces neurotoxins, predominantly the indole-diterpenoid compound lolitrem B. Animals grazing on such pastures develop uncontrollable tremors and become uncoordinated in their movement. Lolitrem B and the structurally related tremor inducer paxilline both act as potent large conductance calcium-activated potassium (BK) channel inhibitors. Using patch clamping, we show that their different apparent affinities correlate with their toxicity in vivo. To investigate whether the motor function deficits produced by lolitrem B and paxilline are due to inhibition of BK ion channels, their ability to induce tremor and ataxia in mice deficient in this ion channel (Kcnma1(-/-)) was examined. Our results show that mice lacking Kcnma1 are unaffected by these neurotoxins. Furthermore, doses of these substances known to be lethal to wild-type mice had no effect on Kcnma1(-/-) mice. These studies reveal the BK channel as the molecular target for the major components of the motor impairments induced by ryegrass neurotoxins. Unexpectedly, when the response to lolitrem B was examined in mice lacking the beta4 BK channel accessory subunit (Kcnmb4(-/-)), only low-level ataxia was observed. Our study therefore reveals a new role for the accessory BK beta4 subunit in motor control. The beta4 subunit could be considered as a potential target for treatment of ataxic conditions in animals and in humans.

  15. Highly improved staggered quarks on the lattice with applications to charm physics

    SciTech Connect

    Follana, E.; Davies, C.; Wong, K.; Mason, Q.; Hornbostel, K.; Lepage, G. P.; Shigemitsu, J.; Trottier, H.

    2007-03-01

    We use perturbative Symanzik improvement to create a new staggered-quark action (HISQ) that has greatly reduced one-loop taste-exchange errors, no tree-level order a{sup 2} errors, and no tree-level order (am){sup 4} errors to leading order in the quark's velocity v/c. We demonstrate with simulations that the resulting action has taste-exchange interactions that are 3-4 times smaller than the widely used ASQTAD action. We show how to bound errors due to taste exchange by comparing ASQTAD and HISQ simulations, and demonstrate with simulations that such errors are likely no more than 1% when HISQ is used for light quarks at lattice spacings of 1/10 fm or less. The suppression of (am){sup 4} errors also makes HISQ the most accurate discretization currently available for simulating c quarks. We demonstrate this in a new analysis of the {psi}-{eta}{sub c} mass splitting using the HISQ action on lattices where am{sub c}=0.43 and 0.66, with full-QCD gluon configurations (from MILC). We obtain a result of 111(5) MeV which compares well with the experiment. We discuss applications of this formalism to D physics and present our first high-precision results for D{sub s} mesons.

  16. Mixed Meson Mass for Domain-Wall Valence and Staggered Sea Fermions

    SciTech Connect

    Konstantinos Orginos; Andre Walker-Loud

    2007-05-01

    Mixed action lattice calculations allow for an additive lattice spacing dependent mass renormalization of mesons composed of one sea and one valence quark, regardless of the type of fermion discretization methods used in the valence and sea sectors. The value of the mass renormalization depends upon the lattice actions used. This mixed meson mass shift is the most important lattice artifact to determine for mixed action calculations: because it modifies the pion mass, it plays a central role in the low energy dynamics of all hadronic correlation functions. We determine the leading order and next to leading order additive mass renormalization of valence-sea mesons for a mixed lattice action with domain-wall valence fermions and staggered sea fermions. We find that on the asqtad improved coarse MILC lattices, the leading order additive mass renormalization for the mixed mesons is Δ(am)^2 LO = 0.0409(11) which corresponds to a^2 Δ_Mix = (319 MeV)^2± (53 MeV)^2 for a = 0.125 fm. We also find significant next to leading order contributions which reduce the mass renormalization by a significant amount, such that for 0 < am_π ≤ 0.22 the mixed meson mass renormalization is well approximated by Δ(am)^2 = 0.0340 (23) or a^2δ_Mix = (290 MeV)^2 ± (76 MeV)^2. The full next-to-leading order analysis is presented in the text.

  17. Development of an explicit non-staggered scheme for solving three-dimensional Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Sheu, Tony W. H.; Chung, Y. W.; Li, J. H.; Wang, Y. C.

    2016-10-01

    An explicit finite-difference scheme for solving the three-dimensional Maxwell's equations in non-staggered grids is presented. We aspire to obtain time-dependent solutions of the Faraday's and Ampère's equations and predict the electric and magnetic fields within the discrete zero-divergence context (or Gauss's law). The local conservation laws in Maxwell's equations are numerically preserved using the explicit second-order accurate symplectic partitioned Runge-Kutta temporal scheme. Following the method of lines, the spatial derivative terms in the semi-discretized Faraday's and Ampère's equations are approximated theoretically to obtain a highly accurate numerical phase velocity. The proposed fourth-order accurate space-centered finite difference scheme minimizes the discrepancy between the exact and numerical phase velocities. This minimization process considerably reduces the dispersion and anisotropy errors normally associated with finite difference time-domain methods. The computational efficiency of getting the same level of accuracy at less computing time and the ability of preserving the symplectic property have been numerically demonstrated through several test problems.

  18. Near-Wall Velocity and Temperature Measurements in the Meniscus Region for Staggered Glass Beads.

    PubMed

    Wang, Zhaochun; Zhou, Leping; Du, Xiaoze; Yang, Yongping

    2015-04-01

    Velocity and temperature fields in the meniscus are crucial for the heat transfer mechanism in porous medium. The meniscus zone, however, is narrow so that it is difficult for observation. The velocimetry and thermometry in the near-wall region of the surface provide possible measurement methods with the development of micro/nanotechnology. Being exponentially decay in the intensity, the evanescent-wave illumination has the advantage of high spatial resolution and non-intrusion for these measurement methods. The multilayer nano-particle image velocimetry (MnPIV) uses the evanescent-wave illumination, decayed exponentially with the wall-normal distance, to obtain near-wall velocity data at different distances from the wall. The thermometry in the meniscus region could also use the evanescent-wave to illuminate the fluorescence dye, the emitted intensity of which changes with temperature. In this paper, these techniques are employed to measure the near-wall velocity and temperature between the porous media and the ITO heater, in order to explore the role of meniscus during convection of water. Near-wall velocity and temperature of the deionized water, seeded with 100 nm fluorescent colloidal tracers and flow in the staggered glass beads with diameters ranging from 2 mm to 6 mm, are obtained and discussed.

  19. The Chebyshev spectral element method using staggered predictor and corrector for elastic wave simulations

    NASA Astrophysics Data System (ADS)

    Che, Cheng-Xuan; Wang, Xiu-Ming; Lin, Wei-Jun

    2010-06-01

    Based on strong and weak forms of elastic wave equations, a Chebyshev spectral element method (SEM) using the Galerkin variational principle is developed by discretizing the wave equation in the spatial and time domains and introducing the preconditioned conjugate gradient (PCG)-element by element (EBE) method in the spatial domain and the staggered predictor/corrector method in the time domain. The accuracy of our proposed method is verified by comparing it with a finite-difference method (FDM) for a homogeneous solid medium and a double layered solid medium with an inclined interface. The modeling results using the two methods are in good agreement with each other. Meanwhile, to show the algorithm capability, the suggested method is used to simulate the wave propagation in a layered medium with a topographic traction free surface. By introducing the EBE algorithm with an optimized tensor product technique, the proposed SEM is especially suitable for numerical simulation of wave propagations in complex models with irregularly free surfaces at a fast convergence rate, while keeping the advantage of the finite element method.

  20. Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

    SciTech Connect

    Triplett, C.E.

    1996-12-01

    This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.