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Sample records for period studied attrition

  1. Development of an attrition risk prediction tool.

    Science.gov (United States)

    Fowler, John; Norrie, Peter

    To review lecturers' and students' perceptions of the factors that may lead to attrition from pre-registration nursing and midwifery programmes and to identify ways to reduce the impact of such factors on the student's experience. Comparable attrition rates for nursing and midwifery students across various universities are difficult to monitor accurately; however, estimates that there is approximately a 25% national attrition rate are not uncommon. The financial and human implications of this are significant and worthy of investigation. A study was carried out in one medium-sized UK school of nursing and midwifery, aimed at identifying perceived factors associated with attrition and retention. Thirty-five lecturers were interviewed individually; 605 students completed a questionnaire, and of these, 10 were individually interviewed. Attrition data kept by the student service department were reviewed. Data were collected over an 18-month period in 2007-2008. Regression analysis of the student data identified eight significant predictors. Four of these were 'positive' factors in that they aided student retention and four were 'negative' in that they were associated with students' thoughts of resigning. Student attrition and retention is multifactorial, and, as such, needs to be managed holistically. One aspect of this management could be an attrition risk prediction tool.

  2. Issues concerning recruitment, retention and attrition of student nurses in the 1950/60s: a comparative study.

    Science.gov (United States)

    Jinks, Annette M; Richardson, Kathleen; Jones, Chris; Kirton, Jennifer A

    2014-11-01

    To investigate student nurse recruitment and attrition in the 1950' and 1960s and undertake comparisons to modern day concerns. The study was set in one hospital in the U.K. In the period studied nursing was unpopular as a profession and there were difficulties surrounding recruitment. Attrition rates were high. Documentary analysis of 641 training records dating 1955 to 1968 was undertaken. Attrition rates, reasons for non-completion and employment following successful completion were determined. Most recruits were young, unmarried, females and had overseas addresses. The majority (n = 88) had prior nursing experience. Over 69% (n = 443) successfully completed their training. Attrition rates were over 30% (n = 198), the main reason being academic failure. Following completion over 40% (n = 183) undertook midwifery training (n = 183) or secured a staff nurse post (n = 153). Issues relating to recruitment, retention and attrition in the 1950s and 1960s put into context present day issues. Recent attrition rates from pre-registration nurse education have fallen, nevertheless some of the issues of yesteryear remain problematic. In the present study significant numbers of entrants left due to domestic and ill-health problems resonates with many modern day studies. Also failure to complete due to academic shortcomings continues to be a concern. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Limestone attrition under simulated oxyfiring Fluidized-Bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Scala, F. [Istituto di Ricerche sulla Combustione - CNR, Napoli (Italy); Salatino, P. [Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Napoli (Italy)

    2009-03-15

    Limestone attrition by surface wear was studied during the flue gas desulfurization under simulated fluidized-bed (FB) oxyfiring conditions and hindered calcination. Bench-scale experimental tests were carried out using well-established techniques previously developed for the characterization of sulfation and attrition of sorbents in air-blown atmospheric FB combustors. The experimental limestone conversion and attrition results were compared with those previously obtained with the same limestone under simulated air-blown combustion conditions. The differences in the conversion and attrition extents and patterns associated with oxyfiring as compared to air-blown atmospheric combustion were highlighted and related to the different particle morphologies and thicknesses of the sulfate layer. It was noted that attrition could play an important role in practical circulating FB combustor operation, by effectively enhancing particle sulfation under both oxyfiring and air-blown combustion conditions. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  4. Medical school attrition-beyond the statistics a ten year retrospective study.

    Science.gov (United States)

    Maher, Bridget M; Hynes, Helen; Sweeney, Catherine; Khashan, Ali S; O'Rourke, Margaret; Doran, Kieran; Harris, Anne; Flynn, Siun O'

    2013-01-31

    Medical school attrition is important--securing a place in medical school is difficult and a high attrition rate can affect the academic reputation of a medical school and staff morale. More important, however, are the personal consequences of dropout for the student. The aims of our study were to examine factors associated with attrition over a ten-year period (2001-2011) and to study the personal effects of dropout on individual students. The study included quantitative analysis of completed cohorts and qualitative analysis of ten-year data. Data were collected from individual student files, examination and admission records, exit interviews and staff interviews. Statistical analysis was carried out on five successive completed cohorts. Qualitative data from student files was transcribed and independently analysed by three authors. Data was coded and categorized and key themes were identified. Overall attrition rate was 5.7% (45/779) in 6 completed cohorts when students who transferred to other medical courses were excluded. Students from Kuwait and United Arab Emirates had the highest dropout rate (RR = 5.70, 95% Confidence Intervals 2.65 to 12.27;p psychological morbidity in 40% (higher than other studies). Qualitative analysis revealed recurrent themes of isolation, failure, and despair. Student Welfare services were only accessed by one-third of dropout students. While dropout is often multifactorial, certain red flag signals may alert us to risk of dropout including non-EU origin, academic struggling, absenteeism, social isolation, depression and leave of absence. Psychological morbidity amongst dropout students is high and Student Welfare services should be actively promoted. Absenteeism should prompt early intervention. Behind every dropout statistic lies a personal story. All medical schools have a duty of care to support students who leave the medical programme.

  5. Association of General Surgery Resident Remediation and Program Director Attitudes With Resident Attrition.

    Science.gov (United States)

    Schwed, Alexander C; Lee, Steven L; Salcedo, Edgardo S; Reeves, Mark E; Inaba, Kenji; Sidwell, Richard A; Amersi, Farin; Are, Chandrakanth; Arnell, Tracey D; Damewood, Richard B; Dent, Daniel L; Donahue, Timothy; Gauvin, Jeffrey; Hartranft, Thomas; Jacobsen, Garth R; Jarman, Benjamin T; Melcher, Marc L; Mellinger, John D; Morris, Jon B; Nehler, Mark; Smith, Brian R; Wolfe, Mary; Kaji, Amy H; de Virgilio, Christian

    2017-12-01

    Previous studies of resident attrition have variably included preliminary residents and likely overestimated categorical resident attrition. Whether program director attitudes affect attrition has been unclear. To determine whether program director attitudes are associated with resident attrition and to measure the categorical resident attrition rate. This multicenter study surveyed 21 US program directors in general surgery about their opinions regarding resident education and attrition. Data on total resident complement, demographic information, and annual attrition were collected from the program directors for the study period of July 1, 2010, to June 30, 2015. The general surgery programs were chosen on the basis of their geographic location, previous collaboration with some coauthors, prior work in surgical education and research, or a program director willing to participate. Only categorical surgical residents were included in the study; thus, program directors were specifically instructed to exclude any preliminary residents in their responses. Five-year attrition rates (2010-2011 to 2014-2015 academic years) as well as first-time pass rates on the General Surgery Qualifying Examination and General Surgery Certifying Examination of the American Board of Surgery (ABS) were collected. High- and low-attrition programs were compared. The 21 programs represented different geographic locations and 12 university-based, 3 university-affiliated, and 6 independent program types. Programs had a median (interquartile range [IQR]) number of 30 (20-48) categorical residents, and few of those residents were women (median [IQR], 12 [5-17]). Overall, 85 of 966 residents (8.8%) left training during the study period: 15 (17.6%) left after postgraduate year 1, 34 (40.0%) after postgraduate year 2, and 36 (42.4%) after postgraduate year 3 or later. Forty-four residents (51.8%) left general surgery for another surgical discipline, 21 (24.7%) transferred to a different surgery

  6. Study of Navy Enlisted Attrition: Race, Ethnicity, and Type of Occupation

    National Research Council Canada - National Science Library

    Carroll, James M

    2008-01-01

    The primary objective of this study is to gain a better understanding of Navy first-term enlisted attrition among racial/ethnic minorities by comparing attrition rates in technical and nontechnical occupations...

  7. Medical School Attrition-Beyond the Statistics A Ten Year Retrospective Study

    Directory of Open Access Journals (Sweden)

    Maher Bridget M

    2013-01-01

    Full Text Available Abstract Background Medical school attrition is important - securing a place in medical school is difficult and a high attrition rate can affect the academic reputation of a medical school and staff morale. More important, however, are the personal consequences of dropout for the student. The aims of our study were to examine factors associated with attrition over a ten-year period (2001–2011 and to study the personal effects of dropout on individual students. Methods The study included quantitative analysis of completed cohorts and qualitative analysis of ten-year data. Data were collected from individual student files, examination and admission records, exit interviews and staff interviews. Statistical analysis was carried out on five successive completed cohorts. Qualitative data from student files was transcribed and independently analysed by three authors. Data was coded and categorized and key themes were identified. Results Overall attrition rate was 5.7% (45/779 in 6 completed cohorts when students who transferred to other medical courses were excluded. Students from Kuwait and United Arab Emirates had the highest dropout rate (RR = 5.70, 95% Confidence Intervals 2.65 to 12.27;p  Absenteeism was documented in 30% of students, academic difficulty in 55.7%, social isolation in 20%, and psychological morbidity in 40% (higher than other studies. Qualitative analysis revealed recurrent themes of isolation, failure, and despair. Student Welfare services were only accessed by one-third of dropout students. Conclusions While dropout is often multifactorial, certain red flag signals may alert us to risk of dropout including non-EU origin, academic struggling, absenteeism, social isolation, depression and leave of absence. Psychological morbidity amongst dropout students is high and Student Welfare services should be actively promoted. Absenteeism should prompt early intervention. Behind every dropout statistic lies a personal story. All

  8. The impact of attrition on the representativeness of cohort studies of older people

    Directory of Open Access Journals (Sweden)

    Brilleman Samuel L

    2010-08-01

    Full Text Available Abstract Background There are well-established risk factors, such as lower education, for attrition of study participants. Consequently, the representativeness of the cohort in a longitudinal study may deteriorate over time. Death is a common form of attrition in cohort studies of older people. The aim of this paper is to examine the effects of death and other forms of attrition on risk factor prevalence in the study cohort and the target population over time. Methods Differential associations between a risk factor and death and non-death attrition are considered under various hypothetical conditions. Empirical data from the Australian Longitudinal Study on Women's Health (ALSWH for participants born in 1921-26 are used to identify associations which occur in practice, and national cross-sectional data from Australian Censuses and National Health Surveys are used to illustrate the evolution of bias over approximately ten years. Results The hypothetical situations illustrate how death and other attrition can theoretically affect changes in bias over time. Between 1996 and 2008, 28.4% of ALSWH participants died, 16.5% withdrew and 10.4% were lost to follow up. There were differential associations with various risk factors, for example, non-English speaking country of birth was associated with non-death attrition but not death whereas being underweight (body mass index Conclusions Deaths occur in both the target population and study cohort, while other forms of attrition occur only in the study cohort. Therefore non-death attrition may cause greater bias than death in longitudinal studies. However although more than a quarter of the oldest participants in the ALSWH died in the 12 years following recruitment, differences from the national population changed only slightly.

  9. The nature and causes of attrition in the British Household Panel Study

    OpenAIRE

    Uhrig, S.C. Noah

    2008-01-01

    Panel attrition is a process producing data absent from panel records due to survey non-participation or other data unavailability. I examine the nature and causes of attrition resulting from non-contact and survey refusal in the British Household Panel Study. Focusing on non-response transitions amongst Wave 1 respondents using discrete time transition models, I locate attrition at first non-response over the first 14 waves. Physical impediments to contact, less time spent at home and high l...

  10. Language Attrition: The Fate of the Start.

    Science.gov (United States)

    Hansen, Lynne

    2001-01-01

    Reviews the literature on psycholinguistic aspects of language attrition over the past half decade. Discusses evidence from studies on hesitation phenomena in attriter speech, variables affecting language attrition, and relearning. (Author/VWL)

  11. Texas Public School Attrition Study, 2011-12. IDRA Report

    Science.gov (United States)

    Johnson, Roy L.; Montes, Felix

    2012-01-01

    This document contains 3 statistical reports. The first report, "Attrition Rate Decline Seems Promising--Though High Schools are Still Losing One in Four Students" (by Roy L. Johnson), presents results of long-term trend assessments of attrition data in Texas public high schools. The second report, "Slow Declining Pace Keeps Zero…

  12. Web-Based Alcohol Intervention: Study of Systematic Attrition of Heavy Drinkers.

    Science.gov (United States)

    Radtke, Theda; Ostergaard, Mathias; Cooke, Richard; Scholz, Urte

    2017-06-28

    Web-based alcohol interventions are a promising way to reduce alcohol consumption because of their anonymity and the possibility of reaching a high numbers of individuals including heavy drinkers. However, Web-based interventions are often characterized by high rates of attrition. To date, very few studies have investigated whether individuals with higher alcohol consumption show higher attrition rates in Web-based alcohol interventions as compared with individuals with lower alcohol consumption. The aim of this study was to examine the attrition rate and predictors of attrition in a Web-based intervention study on alcohol consumption. The analysis of the predictors of attrition rate was performed on data collected in a Web-based randomized control trial. Data collection took place at the University of Konstanz, Germany. A total of 898 people, which consisted of 46.8% males (420/898) and 53.2% females (478/898) with a mean age of 23.57 years (SD 5.19), initially volunteered to participate in a Web-based intervention study to reduce alcohol consumption. Out of the sample, 86.9% (781/898) were students. Participants were classified as non-completers (439/898, 48.9%) if they did not complete the Web-based intervention. Potential predictors of attrition were self-reported: alcohol consumption in the last seven days, per week, from Monday to Thursday, on weekends, excessive drinking behavior measured with the Alcohol Use Disorder Identification Test (AUDIT), and drinking motives measured by the Drinking Motive Questionnaire (DMQ-R SF). Significant differences between completers and non-completers emerged regarding alcohol consumption in the last seven days (B=-.02, P=.05, 95% CI [0.97-1.00]), on weekends (B=-.05, P=.003, 95% CI [0.92-0.98]), the AUDIT (B=-.06, P=.007, 95% CI [0.90-0.98], and the status as a student (B=.72, P=.001, 95% CI [1.35-3.11]). Most importantly, non-completers had a significantly higher alcohol consumption compared with completers. Hazardous

  13. Attrition Cost Model Instruction Manual

    Science.gov (United States)

    Yanagiura, Takeshi

    2012-01-01

    This instruction manual explains in detail how to use the Attrition Cost Model program, which estimates the cost of student attrition for a state's higher education system. Programmed with SAS, this model allows users to instantly calculate the cost of attrition and the cumulative attrition rate that is based on the most recent retention and…

  14. Exploring Beginning Teachers' Attrition in the Netherlands

    Science.gov (United States)

    den Brok, Perry; Wubbels, Theo; van Tartwijk, Jan

    2017-01-01

    Based on a review of recent studies and reports, this research investigates attrition among beginning teachers in the Netherlands as well as reasons for teacher attrition, and compares the finding with studies on this topic conducted elsewhere in the world. The findings suggest that attrition among beginning teachers in the Netherlands with a…

  15. Texas Public School Attrition Study, 2013-14. IDRA Report

    Science.gov (United States)

    Johnson, Roy L.; Montes, Felix

    2014-01-01

    Since 1986, Intercultural Development Research Association (IDRA) has conducted an annual attrition study to track the number and percent of students in Texas who are lost from public secondary school enrollment prior to graduation. The study builds on the series of studies that began when IDRA conducted the first comprehensive study of school…

  16. Texas Public School Attrition Study, 2016-17. IDRA Report

    Science.gov (United States)

    Johnson, Roy L.; Montes, Felix

    2017-01-01

    Since 1986, Intercultural Development Research Association (IDRA) has conducted an annual attrition study to track the number and percent of students in Texas who are lost from public secondary school enrollment prior to graduation. The study builds on the series of studies that began when IDRA conducted the first comprehensive study of school…

  17. Texas Public School Attrition Study, 2014-15. IDRA Report

    Science.gov (United States)

    Johnson, Roy L.; Montes, Felix

    2015-01-01

    Since 1986, Intercultural Development Research Association (IDRA) has conducted an annual attrition study to track the number and percent of students in Texas who are lost from public secondary school enrollment prior to graduation. The study builds on the series of studies that began when IDRA conducted the first comprehensive study of school…

  18. Texas Public School Attrition Study, 2015-16. IDRA Report

    Science.gov (United States)

    Johnson, Roy L.; Montes, Felix; Hinojosa, David

    2016-01-01

    Since 1986, Intercultural Development Research Association (IDRA) has conducted an annual attrition study to track the number and percent of students in Texas who are lost from public secondary school enrollment prior to graduation. The study builds on the series of studies that began when IDRA conducted the first comprehensive study of school…

  19. A qualitative and quantitative study of the reasons of attrition in an Indian hospital

    Directory of Open Access Journals (Sweden)

    Kasturi Shukla

    2017-01-01

    Full Text Available Background: The study attempts to evaluate the reasons of attrition in the organization from the perspective of the existing as well as the leaving employees; compare and identify the gaps, if any between the perspectives of these two employees groups. The study also aims to critically analyze the utility of ′exit interviews′ for analyzing the reasons of attrition. Methods: This cross-sectional study was conducted in a 150-bedded hospital in Ahmedabad, India, during May-July 2015. Exit interview data of forty leaving employees were collected and reviewed. One hundred existing employees were interviewed through quantitative and qualitative methods to understand their perceptions about attrition in the organization. Results: Attrition rate of 26% was observed in the study and 57% leaving employees were nurses. 70% leaving employees cite "blanket reasons" such as better opportunity and personal reasons during exit interviews. 72.5% leaving employees believed that exit interview is largely for record purpose and 11% were unsure of its utility. However, when existing employees were probed qualitatively, a variety of responses were received. 65% existing employees quoted salary issues, partiality/poor recognition, improper assignment of tasks, and monotonous work as reasons for attrition in the organization. Conclusion: Exit interviews somewhere fail to probe into the real reasons of attrition. To improve retention, organizations must monitor their existing employee′s intention to continue working in the organization and any sign indicating a poor intention to continue must be addressed immediately to avoid ripple effects. Moreover, to use exit interview as a tool to improve employee retention, leaving employees must be interviewed in-depth to uncover the actual reasons for quitting the job.

  20. When did they leave, and why? A retrospective case study of attrition on the Nottingham undergraduate medical course

    Directory of Open Access Journals (Sweden)

    Yates Janet

    2012-06-01

    Full Text Available Abstract Background As part of a wider study into students who experience difficulties, we examined the course files of those who had failed to graduate. This was an exploratory, descriptive study investigating how many students left after academic failure or non-academic problems, or simply changed their minds about reading medicine, and at what stage. The aim of the study was to increase our knowledge about the timings of, and reasons for, attrition. This understanding might help to reduce student loss in the future, by informing selection procedures and improving pastoral support at critical times. It might also assist in long-term workforce planning in the NHS. Methods Relevant data on admission and course progress were extracted manually from the archived files of students who had failed to graduate from five recent consecutive cohorts (entry in 2000–2004 inclusive, using a customised Access database. Discrete categories of information were supplemented with free text entries. Results 1188 students registered over the five-year entry period and 73 (6% failed to graduate. The highest rates of attrition (46/1188, 4% occurred during the first two years (largely preclinical studies, with 34 students leaving voluntarily, including 11 within the first semester, and 12 having their courses terminated for academic failure. Seventeen left at the end of the third year (Honours course plus early clinical practice and the remaining ten during the final two clinical years. The reasons for attrition were not always clear-cut and often involved a mixture of academic, personal, social and health factors, especially mental health problems. Conclusions The causes of attrition are complex. A small number of students with clear academic failure might require individual educational interventions for remediation. However, this could have substantial resource implications for the Faculty. Mental health problems predominate in late course attrition and may have

  1. Retention and Attrition Among African Americans in the STAR*D Study: What Causes Research Volunteers to Stay or Stray?

    Science.gov (United States)

    Murphy, Eleanor J; Kassem, Layla; Chemerinski, Anat; Rush, A. John; Laje, Gonzalo; McMahon, Francis J.

    2013-01-01

    Background High attrition rates among African-Americans (AA) volunteers are a persistent problem that makes clinical trials less representative and complicates estimation of treatment outcomes. Many studies contrast AA with other ethnic/racial groups, but few compare the AA volunteers who remain in treatment with those who leave. Here, in addition to comparing patterns of attrition between African Americans and whites, we identify predictors of overall and early attrition among African Americans. Method Sample comprised non-Hispanic African-American (n=673) and white (n=2,549) participants in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. Chi-square tests were used to examine racial group differences in reasons for exit. Multivariate logistic regression was used to examine predictors of overall attrition, early attrition (by Level 2) and top reasons cited for attrition among African Americans. Results For both African-American and white dropouts, non-compliance reasons for attrition were most commonly cited during the earlier phases of the study while reasons related to efficacy and medication side effects were cited later in the study. Satisfaction with treatment strongly predicted overall attrition among African Americans independent of socioeconomic, clinical, medical or psychosocial factors. Early attrition among African American dropouts was associated with less psychiatric comorbidity, and higher perceived physical functioning but greater severity of clinician-rated depression. Conclusions The decision to drop out is a dynamic process that changes over the course of a clinical trial. Strategies aimed at retaining African Americans in such trials should emphasize engagement with treatment and patient satisfaction immediately following enrollment and after treatment initiation. PMID:23723044

  2. Attrition, occlusion, (dys)function, and intervention: a systematic review.

    Science.gov (United States)

    van 't Spijker, Arie; Kreulen, Cees M; Creugers, Nico H J

    2007-06-01

    Attrition and occlusal factors and masticatory function or dysfunction are thought to be related. This study aims to systematically review the literature on this topic with the emphasis to find evidence for occlusion-based treatment protocols for attrition. Literature was searched using PubMed (1980 to 2/2006) and the Cochrane Library of Clinical Trials with the keywords 'tooth' and 'wear'. Five steps were followed. Exclusion was based on the following: (1) reviews, case-reports, studies on non-human tooth material, and studies not published in English and (2) historical or forensic studies. Included were (3) in vivo studies. Next, studies on (4) occlusal factors, function or dysfunction [temporomandibular disorders (TMD), bruxism], or intervention, and (5) attrition were included. Two investigators independently assessed the abstracts; measure of agreement was calculated using Cohen's kappa; disagreement was resolved by discussion. Full-text articles were obtained and correlation between outcomes on occlusal factors, (dys)function, treatment, and attrition were retrieved. References in the papers included in the final analysis were cross-matched with the original list of references to add references that met the inclusion criteria. The search procedure revealed 1289 references on tooth wear. The numbers of included studies after each step were (1) 345 (kappa=0.8), (2) 287 (kappa=0.87), (3) 174 (kappa=0.99), (4) 81 (kappa=0.71), and (5) 27 (kappa=0.68). Hand searches through the reference lists revealed six additional papers to be included. Analysis of the 33 included papers failed to find sound evidence for recommending a certain occlusion-based treatment protocol above another in the management of attrition. Some studies reported correlations between attrition and anterior spatial relationships. No studies were found suggesting that absent posterior support necessarily leads to increased attrition, though one study found that fewer number of teeth resulted in

  3. Study of Attrition Documentation at the U.S. Navy Recruit Training Command

    National Research Council Canada - National Science Library

    Condon, Nancy K; Eckenrode, John E

    2006-01-01

    .... Navy's Recruit Training Command (RTC). A random sample of 754 "retained files" from Customer Service Desk RTC was examined for attrition documentation and the information obtained was compared with attrition documentation contained...

  4. DEVELOPMENT OF ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

    International Nuclear Information System (INIS)

    Adeyinka A. Adeyiga

    2001-01-01

    -based catalysts synthesized at Hampton University, (ii) seek improvements in the catalyst performance through variations in process conditions, pretreatment procedures and/or modifications in catalyst preparation steps and (iii) investigate the performance in a slurry reactor. The effort during the reporting period has been devoted to attrition study of the iron-based catalysts. Precipitated silica appeared to decrease attrition resistance of spray-dried iron FT catalysts. It was found that the catalyst with precipitated silica content at around 12wt% showed the lowest attrition resistance. The results of net change in volume moment and catalyst morphology showed supporting evidences to the attrition results. Catalysts with low attrition resistance generated more fines loss, had higher net change in volume moment and showed more breakage of particles. BET surface area and pore volume of this catalyst series fluctuated; therefore no conclusion can be drawn from the data obtained. However, catalyst with no precipitated silica showed the lowest in BET surface area and pore volume, as expected. Addition of precipitated silica to the catalysts had no effect to the phase changes of iron that could have significant influence to catalyst attrition. The presence of precipitated silica is needed for enhancing catalyst surface area; however, the amount of silica added should be compromising with attrition resistance of catalysts

  5. A Correlational Study of a Reading Comprehension Program and Attrition Rates of ESL Nursing Students in Texas.

    Science.gov (United States)

    Donnell, Wendy M

    The purpose of this study was to examine the associations between English as a second language (ESL), a reading comprehension program, and attrition rates of nursing students. Higher attrition rates of ESL nursing students are an assumption, seemingly based on anecdotal evidence. Data reflecting ESL student attrition should be measured and analyzed so that students can be identified prior to attrition. A secondary analysis of a large database of 27 initial licensure programs in Texas was completed. Data analysis identified that ESL students who used a reading comprehension program were almost twice as likely to be off track or out of the program as ESL students who did not use the program. Nurse educators need to evaluate student profile characteristics in a comprehensive way when determining risk of attrition.

  6. The Impact of Fund Attrition on Superannuation Returns

    OpenAIRE

    Drew, Michael E.; Stanford, Jon D.

    2001-01-01

    This paper investigates the impact of fund attrition on returns from a sample of superannuation fund managers (specialising in the management of domestic stock portfolios) for the period 1991 through 1999, using a four-factor asset pricing model. Survivorship bias is estimated at 23 basis points per annum. The evidence presented in this study is consistent with recent international evidence that suggests that a sampling technique that excludes terminated funds would result in an overestimatio...

  7. An experimental study on the primary fragmentation and attrition of limestones in a fluidized bed

    International Nuclear Information System (INIS)

    Yao, Xuan; Zhang, Hai; Yang, Hairui; Liu, Qing; Wang, Jinwei; Yue, Guangxi

    2010-01-01

    In this paper, an experimental study on the primary fragmentation and attrition of 5 limestones in a fluidized bed was conducted. The intensity of fragmentation and attrition were measured in the same apparatus but at different fluidizing velocities. It was found that the averaged size of the particles decreased by about 10-20% during the fragmentation process. The important factors for particle comminution include limestone types, heating rate, calcination condition and ambient CO 2 concentration. Fragmentation mainly occurred in the first a few minutes in the fluidized bed and it was more intense than that in the muffle furnace at the same temperature. The original size effect was ambiguous, depending on the limestone type. The comminution caused by attrition mainly occurred during calcination process rather than sulphation process. The sulphation process was fragmentation and attrition resisted. The attrition rate of sulphate was similar to that of lime in trend, decaying exponentially with time, but was one-magnitude-order smaller than that of lime. Present experimental results indicate that fragmentation mechanism of the limestone is dominated by CO 2 release instead of thermal stress. (author)

  8. Bounding the effects of social experiments: accounting for attrition in administrative data.

    Science.gov (United States)

    Grogger, Jeffrey

    2012-12-01

    Social experiments frequently exploit data from administrative records. However, most administrative data systems are designed to track earnings or benefit payments among residents within a single state. When an experimental participant moves across state lines, his entries in the data system of his state of origin consist entirely of zeros. Such attrition may bias the estimated effect of the experiment. To estimate the attrition arising from interstate mobility and provide bounds on the effect of the experiment. Attrition is estimated from runs of zeros at the end of the sample period. Bounds are constructed from these estimates. These estimates can be refined by imposing a stationarity assumption. The width of the estimated bounds depends importantly on the nature of the data being analyzed. Negatively correlated outcomes provide tighter bounds than positively correlated outcomes. Attrition can introduce considerable ambiguity into the estimated effects of experimental programs. To reduce ambiguity, one should collect as much data as possible. Even data on outcomes of no direct interest to the objectives of the experiment may be valuable for reducing the ambiguity that arises due to attrition.

  9. The pattern of attrition from an antiretroviral treatment program in Nigeria.

    Directory of Open Access Journals (Sweden)

    Solomon Odafe

    Full Text Available To evaluate the rate and factors associated with attrition of patients receiving ART in tertiary and secondary hospitals in Nigeria.We reviewed patient level data collected between 2007 and 2010 from 11 hospitals across Nigeria. Kaplan-Meier product-limit and Cox regression were used to determine probability of retention in care and risk factors for attrition respectively. Of 6,408 patients in the cohort, 3,839 (59.9% were females, median age of study population was 33years (IQR: 27-40 and 4,415 (69% were from secondary health facilities. The NRTI backbone was Stavudine (D4T in 3708 (57.9% and Zidovudine (ZDV in 2613 (40.8% of patients. Patients lost to follow up accounted for 62.7% of all attrition followed by treatment stops (25.3% and deaths (12.0%. Attrition was 14.1 (N = 624 and 15.1% (N = 300 in secondary and tertiary hospitals respectively (p = 0.169 in the first 12 months on follow up. During the 13 to 24 months follow up period, attrition was 10.7% (N = 407 and 19.6% (N = 332 in secondary and tertiary facilities respectively (p<0.001. Median time to lost to follow up was 11.1 (IQR: 6.1 to 18.5 months in secondary compared with 13.6 (IQR: 9.9 to 17.0 months in tertiary sites (p = 0.002. At 24 months follow up, male gender [AHR 1.18, 95% CI: 1.01-1.37, P = 0.038]; WHO clinical stage III [AHR 1.30, 95%CI: 1.03-1.66, P = 0.03] and clinical stage IV [AHR 1.90, 95%CI: 1.20-3.02, p = 0.007] and care in a tertiary hospital [AHR 2.21, 95% CI: 1.83-2.67, p<0.001], were associated with attrition.Attrition could potentially be reduced by decentralizing patients on ART after the first 12 months on therapy to lower level facilities, earlier initiation on treatment and strengthening adherence counseling amongst males.

  10. Forms of Attrition in a Longitudinal Study of Religion and Health in Older Adults and Implications for Sample Bias.

    Science.gov (United States)

    Hayward, R David; Krause, Neal

    2016-02-01

    The use of longitudinal designs in the field of religion and health makes it important to understand how attrition bias may affect findings in this area. This study examines attrition in a 4-wave, 8-year study of older adults. Attrition resulted in a sample biased toward more educated and more religiously involved individuals. Conditional linear growth curve models found that trajectories of change for some variables differed among attrition categories. Ineligibles had worsening depression, declining control, and declining attendance. Mortality was associated with worsening religious coping styles. Refusers experienced worsening depression. Nevertheless, there was no evidence of bias in the key religion and health results.

  11. Blood Telomere Length Attrition and Cancer Development in the Normative Aging Study Cohort

    Directory of Open Access Journals (Sweden)

    Lifang Hou

    2015-06-01

    Interpretation: Age-related BTL attrition was faster in cancer cases but their age-adjusted BTL attrition began decelerating as diagnosis approached. This may explain prior inconsistencies and help develop BTL as a cancer detection biomarker.

  12. A Comparative Study of Administrator and Special Education Teacher Perceptions of Special Education Teacher Attrition and Retention

    Science.gov (United States)

    Sheldrake, Danielle Angelina

    2013-01-01

    This mixed methods study identifies perceived causes of and solutions to the attrition of special education teachers. Researchers have documented that special education teaching positions encounter higher attrition rates than their general education peers (Katsiyannis, Zhang, & Conroy in Olivarez & Arnold, 2006; Mitchell & Arnold,…

  13. Demographic and psychological predictors of panel attrition: evidence from the New Zealand attitudes and values study.

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    Nicole Satherley

    Full Text Available This study examines attrition rates over the first four years of the New Zealand Attitudes and Values Study, a longitudinal national panel sample of New Zealand adults. We report the base rate and covariates for the following four distinct classes of respondents: explicit withdrawals, lost respondents, intermittent respondents and constant respondents. A multinomial logistic regression examined an extensive range of demographic and socio-psychological covariates (among them the Big-Six personality traits associated with membership in these classes (N = 5,814. Results indicated that men, Māori and Asian peoples were less likely to be constant respondents. Conscientiousness and Honesty-Humility were also positively associated with membership in the constant respondent class. Notably, the effect sizes for the socio-psychological covariates of panel attrition tended to match or exceed those of standard demographic covariates. This investigation broadens the focus of research on panel attrition beyond demographics by including a comprehensive set of socio-psychological covariates. Our findings show that core psychological covariates convey important information about panel attrition, and are practically important to the management of longitudinal panel samples like the New Zealand Attitudes and Values Study.

  14. Personality, attrition and weight loss in treatment seeking women with obesity.

    Science.gov (United States)

    Dalle Grave, R; Calugi, S; Compare, A; El Ghoch, M; Petroni, M L; Colombari, S; Minniti, A; Marchesini, G

    2015-10-01

    Studies on small samples or in single units applying specific treatment programmes found an association between some personality traits and attrition and weight loss in individuals treated for obesity. We aimed to investigate whether pre-treatment personality traits were associated with weight loss outcomes in the general population of women with obesity. Attrition and weight loss outcomes after 12 months were measured in 634 women with obesity (mean age, 48; body mass index (BMI), 37.8 kg m(-2)) seeking treatment at eight Italian medical centres, applying different medical/cognitive behavioural programmes. Personality traits were assessed with the Temperament and Character Inventory (TCI), eating disorder features with the Binge Eating Scale (BES) and Night Eating Questionnaire (NEQ). Within the 12-month observation period, 32.3% of cases were lost to follow-up. After adjustment for demographic confounders and the severity of eating disorders, no TCI personality traits were significantly associated with attrition, while low scores of the novelty seeking temperament scale remained significantly associated with weight loss ≥ 10% (odds ratio, 0.983; 95% confidence interval, 0.975-0.992). Additional adjustment for education and job did not change the results. We conclude that personality does not systematically influence attrition in women with obesity enrolled into weight loss programmes in the community, whereas an association is maintained between novelty seeking and weight loss outcome. Studies adapting obesity interventions on the basis of individual novelty seeking scores might be warranted to maximize the results on body weight. © 2015 World Obesity.

  15. Attrition during a randomized controlled trial of reduced nicotine content cigarettes as a proxy for understanding acceptability of nicotine product standards.

    Science.gov (United States)

    Mercincavage, Melissa; Wileyto, E Paul; Saddleson, Megan L; Lochbuehler, Kirsten; Donny, Eric C; Strasser, Andrew A

    2017-06-01

    To determine (1) if nicotine content affects study attrition-a potential behavioral measure of acceptability-in a trial that required compliance with three levels of reduced nicotine content (RNC) cigarettes, and (2) if attrition is associated with subjective and behavioral responses to RNC cigarettes. Secondary analysis of a 35-day, parallel-design, open-label, randomized controlled trial. After a 5-day baseline period, participants were randomized to smoke for three 10-day periods: their preferred brand (control group) or RNC cigarettes with three nicotine levels in a within-subject stepdown (one group: high-moderate-low) or non-stepdown (five groups: high-low-moderate, low-moderate-high, low-high-moderate, moderate-low-high, moderate-high-low) fashion. A single site in Philadelphia, PA, USA. A total of 246 non-treatment-seeking daily smokers [mean age = 39.52, cigarettes per day (CPD) = 20.95, 68.3% white] were recruited from October 2007 to June 2013. The primary outcome was attrition. Key predictors were nicotine content transition and study period. Exploratory predictors were taste and strength subjective ratings, total puff volume and carbon monoxide (CO) boost. Covariates included: age, gender, race, education and nicotine dependence. Overall attrition was 31.3% (n = 77): 24.1% of the control and 25.0% of the stepdown RNC cigarette groups dropped out versus 44.6% of non-stepdown groups (P = 0.006). Compared with controls, attrition odds were 4.5 and 4.7 times greater among smokers transitioning from preferred and the highest RNC cigarettes to the lowest RNC cigarettes, respectively (P = 0.001 and 0.003). Providing more favorable initial taste ratings of study cigarettes decreased attrition odds by 2% (P = 0.012). The majority of participants completed a 35-day trial of varying levels of reduced nicotine content cigarettes. Participant dropout was greater for cigarettes with lower nicotine content and less in smokers reporting more favorable

  16. The Rapier or the Club: The Relationship between Attrition and Maneuver Warfare

    National Research Council Canada - National Science Library

    Springman, Jeffrey A

    2006-01-01

    ...? This project compares the relationship between attrition and maneuver warfare. The study considers whether there are times when wars of attrition should be fought, and whether there are conditions that force wars of attrition...

  17. Flotability Improvement of Ilmenite Using Attrition-Scrubbing as a Pretreatment Method

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    Jihua Zhai

    2017-01-01

    Full Text Available Flotation technology of the recovery and utilization of ilmenite from tailings of iron beneficiated in Panzhihua was investigated based on mineralogical study. The results of mineralogical study show that the main occurrence of the valuable mineral are liberated grains of ilmenite. Experimental results of flotation conditions show that attrition-scrubbing raw ores exhibit good flotability with higher recoveries and a slight decrease in grade compared to ores without attrition-scrubbing. Further, open-circuit experiments also prove the superiority of attrition-scrubbing raw ores. The results of closed-circuit experiments show that qualified ilmenite concentrate can be obtained and the yield, grade, and recovery are 22.26%, 47.06%, and 60.73%, respectively. Theoretical study and analysis show that there are two contributions to superior flotability for attrition-scrubbing samples. The first is that the attrition-scrubbing samples can uncover more ferrous ions on the newly-produced fresh ilmenite surface, resulting in the increase in active sites. The other is that in the process of attrition-scrubbing, the transformation of ferrous ions to ferric ions can be promoted.

  18. Weight Loss Expectations and Attrition in Treatment-Seeking Obese Women

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    Riccardo Dalle Grave

    2015-10-01

    Full Text Available Objective: The analysis of the relation between weight loss goals and attrition in the treatment of obesity has produced conflicting results. The aim of the present study was to investigate the role of weight loss goals on attrition in a cohort of obese women seeking treatment at 8 Italian medical centres. Methods: 634 women with obesity, consecutively enrolled in weight loss programmes, were included in the study. Weight loss goals were evaluated with the Goals and Relative Weights Questionnaire (GRWQ, reporting a sequence of unrealistic (‘dream' and ‘happy' and more realistic (‘acceptable' and ‘disappointing' weight loss goals. Attrition was assessed at 12 months on the basis of patients' medical records. Results: At 12 months, 205/634 patients (32.3% had interrupted their programme and were lost to follow-up. After adjustment for age, baseline weight, education and employment status, attrition was significantly associated with higher percent acceptable and disappointing weight loss targets, not with dream and happy weight loss. Conclusion: In ‘real world' clinical settings, only realistic expectations might favour attrition whenever too challenging, whereas unrealistic weight loss goals have no effect. Future studies should assess the effect of interventions aimed at coping with too challenging weight goals on attrition.

  19. Early Career Teacher Attrition: Intentions of Teachers Beginning

    Science.gov (United States)

    Clandinin, D. Jean; Long, Julie; Schaefer, Lee; Downey, C. Aiden; Steeves, Pam; Pinnegar, Eliza; McKenzie Robblee, Sue; Wnuk, Sheri

    2015-01-01

    Early career teacher attrition has most often been conceptualized as either a problem associated with individual factors (e.g. burnout) or a problem associated with contextual factors (e.g. support and salary). This study considered early career teacher attrition as an identity making process that involves a complex negotiation between individual…

  20. Influence of attrition variables on iron ore flotation

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    Fabiana Fonseca Fortes

    Full Text Available Abstract The presence of slimes is harmful to the flotation process: the performance and consumption of reagents are negatively affected. Traditionally, the desliming stage has been responsible for removing slimes. However, depending on the porosity of the mineral particles, desliming may not be sufficient to maximize the concentration results. An attrition process before the desliming operation can improve the removal of slime, especially when slimes cover the surface and/or are confined to the cavities/pores of the mineral particles. Attrition is present in the flowcharts of the beneficiation process of phosphate and industrial sand (silica sand. Research has been undertaken for its application to produce pre-concentrates of zircon and iron ore. However, there is still little knowledge of the influence of the attrition variables on the beneficiation process of iron ore. This study presents a factorial design and analysis of the effects of these variables on the reverse flotation of iron ore. The standard of the experimental procedures for all tests included the attrition of pulp, under the conditions of dispersion, desliming and flotation. The parameter analysed (variable response was the metallurgical recovery in reverse flotation tests. The planning and analysis of the full factorial experiment indicated that with 95% reliability, the rotation speed of the attrition cell impeller was the main variable in the attrition process of the iron ore. The percentage of solid variables in the pulp and the time of the attrition, as well as their interactions, were not indicated to be significant.

  1. Factors associated with attrition, mortality, and loss to follow up after antiretroviral therapy initiation: data from an HIV cohort study in India

    Directory of Open Access Journals (Sweden)

    Gerardo Alvarez-Uria

    2013-09-01

    Full Text Available Background: Studies from sub-Saharan Africa have shown high incidence of attrition due to mortality or loss to follow-up (LTFU after initiating antiretroviral therapy (ART. India is the third largest country in the world in terms of HIV infected people, but predictors of attrition after ART initiation are not well known. Design: We describe factors associated with attrition, mortality, and LTFU in 3,159 HIV infected patients who initiated ART between 1 January 2007 and 4 November 2011 in an HIV cohort study in India. The study included 6,852 person-years with a mean follow-up of 2.17 years. Results: After 5 years of follow-up, the estimated cumulative incidence of attrition was 37.7%. There was no significant difference between attrition due to mortality and attrition due to LTFU. Having CD4 counts <100 cells/µl and being homeless [adjusted hazard ratio (aHR 3.1, 95% confidence interval (CI 2.6–3.8] were associated with a higher risk of attrition, and female gender (aHR 0.64, 95% CI 0.6–0.8 was associated with a reduced risk of attrition. Living near a town (aHR 0.82, 95% CI 0.7–0.999 was associated with a reduced risk of mortality. Being single (aHR 1.6, 95% CI 1.2–2.3, illiteracy (aHR 1.3, 95% CI 1.1–1.6, and age <25 years (aHR 1.3, 95% CI 1–1.8 were associated with an increased risk of LTFU. Although the cumulative incidence of attrition in patients diagnosed with tuberculosis after ART initiation was 47.4%, patients who started anti-tuberculous treatment before ART had similar attrition to patients without tuberculosis (36 vs. 35.2%, P=0.19 after four years of follow-up. Conclusions: In this cohort study, the attrition was similar to the one found in sub-Saharan Africa. Earlier initiation of ART, improving the diagnosis of tuberculosis before initiating ART, and giving more support to those patients at higher risk of attrition could potentially reduce the mortality and LTFU after ART initiation.

  2. Attrition during graduate medical education: medical school perspective.

    Science.gov (United States)

    Andriole, Dorothy A; Jeffe, Donna B; Hageman, Heather L; Klingensmith, Mary E; McAlister, Rebecca P; Whelan, Alison J

    2008-12-01

    To identify predictors of attrition during graduate medical education (GME) in a single medical school cohort of contemporary US medical school graduates. Retrospective cohort study. Single medical institution. Recent US allopathic medical school graduates. Attrition from initial GME program. Forty-seven of 795 graduates (6%) did not complete the GME in their initial specialty of choice. At bivariate analysis, attrition was associated with election to the Alpha Omega Alpha Honor Medical Society, being an MD-PhD degree holder, and specialty choice (all P PhD degree holder (odds ratio, 3.43; 95% confidence interval, 1.27-9.26; P = .02), election to Alpha Omega Alpha (2.19; 1.04-4.66; P = .04), choice of general surgery for GME (5.32; 1.98-14.27; P < .001), and choice of 5-year surgical specialty including those surgical specialties with a GME training requirement of 5 years or longer (2.74; 1.16-6.44; P = .02) each independently predicted greater likelihood of attrition. Academically highly qualified graduates and graduates who chose training in general surgery or in a 5-year surgical specialty were at increased risk of attrition during GME.

  3. Attrition from Web-Based Cognitive Testing: A Repeated Measures Comparison of Gamification Techniques.

    Science.gov (United States)

    Lumsden, Jim; Skinner, Andy; Coyle, David; Lawrence, Natalia; Munafo, Marcus

    2017-11-22

    The prospect of assessing cognition longitudinally and remotely is attractive to researchers, health practitioners, and pharmaceutical companies alike. However, such repeated testing regimes place a considerable burden on participants, and with cognitive tasks typically being regarded as effortful and unengaging, these studies may experience high levels of participant attrition. One potential solution is to gamify these tasks to make them more engaging: increasing participant willingness to take part and reducing attrition. However, such an approach must balance task validity with the introduction of entertaining gamelike elements. This study aims to investigate the effects of gamelike features on participant attrition using a between-subjects, longitudinal Web-based testing study. We used three variants of a common cognitive task, the Stop Signal Task (SST), with a single gamelike feature in each: one variant where points were rewarded for performing optimally; another where the task was given a graphical theme; and a third variant, which was a standard SST and served as a control condition. Participants completed four compulsory test sessions over 4 consecutive days before entering a 6-day voluntary testing period where they faced a daily decision to either drop out or continue taking part. Participants were paid for each session they completed. A total of 482 participants signed up to take part in the study, with 265 completing the requisite four consecutive test sessions. No evidence of an effect of gamification on attrition was observed. A log-rank test showed no evidence of a difference in dropout rates between task variants (χ 2 2 =3.0, P=.22), and a one-way analysis of variance of the mean number of sessions completed per participant in each variant also showed no evidence of a difference (F 2,262 =1.534, P=.21, partial η 2 =0.012). Our findings raise doubts about the ability of gamification to reduce attrition from longitudinal cognitive testing studies

  4. Predictors of early faculty attrition at one Academic Medical Center.

    Science.gov (United States)

    Bucklin, Brenda A; Valley, Morgan; Welch, Cheryl; Tran, Zung Vu; Lowenstein, Steven R

    2014-02-10

    Faculty turnover threatens the research, teaching and clinical missions of medical schools. We measured early attrition among newly-hired medical school faculty and identified personal and institutional factors associated with early attrition. This retrospective cohort study identified faculty hired during the 2005-2006 academic year at one school. Three-year attrition rates were measured. A 40-question electronic survey measured demographics, career satisfaction, faculty responsibilities, institutional/departmental support, and reasons for resignation. Odds ratios (ORs) and 95 percent confidence intervals (95% CI) identified variables associated with early attrition. Of 139 faculty, 34% (95% CI = 26-42%) resigned within three years of hire. Attrition was associated with: perceived failure of the Department Chair to foster a climate of teaching, research, and service (OR = 6.03; 95% CI: 1.84, 19.69), inclusiveness, respect, and open communication (OR = 3.21; 95% CI: 1.04, 9.98). Lack of professional development of the faculty member (OR = 3.84; 95% CI: 1.25, 11.81); institutional recognition and support for excellence in teaching (OR = 2.96; 95% CI: 0.78, 11.19) and clinical care (OR = 3.87; 95% CI: 1.04, 14.41); and >50% of professional time devoted to patient care (OR = 3.93; 95% CI: 1.29, 11.93) predicted attrition. Gender, race, ethnicity, academic degree, department type and tenure status did not predict early attrition. Of still-active faculty, an additional 27 (48.2%, 95% CI: 35.8, 61.0) reported considering resignation within the 5 years. In this pilot study, one-third of new faculty resigned within 3 years of hire. Greater awareness of predictors of early attrition may help schools identify threats to faculty career satisfaction and retention.

  5. ART attrition and risk factors among Option B+ patients in Haiti: A retrospective cohort study.

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    Nancy Puttkammer

    Full Text Available In October 2012, the Haitian Ministry of Health endorsed the "Option B+" strategy to eliminate mother-to-child transmission of HIV and achieve HIV epidemic control. The objective of this paper is to assess and identify risk factors for attrition from the national ART program among Option B+ patients in the 12 months after ART initiation.This retrospective cohort study included patients newly initiating ART from October 2012-August 2013 at 68 ART sites covering 45% of all newly enrolled ART patients in all regions of Haiti.With data from electronic medical records, we carried out descriptive analysis of sociodemographic, clinical, and pregnancy-related correlates of ART attrition, and used a modified Poisson regression approach to estimate relative risks in a multivariable model.There were 2,166 Option B+ patients who initiated ART, of whom 1,023 were not retained by 12 months (47.2%. One quarter (25.3% dropped out within 3 months of ART initiation. Protective factors included older age, more advanced HIV disease progression, and any adherence counseling prior to ART initiation, while risk factors included starting ART late in gestation, starting ART within 7 days of HIV testing, and using an atypical ART regimen.Our study demonstrates early ART attrition among Option B+ patients and contributes evidence on the characteristics of women who are most at risk of attrition in Haiti. Our findings highlight the importance of targeted strategies to support retention among Option B+ patients.

  6. Selective attrition and intraindividual variability in response time moderate cognitive change.

    Science.gov (United States)

    Yao, Christie; Stawski, Robert S; Hultsch, David F; MacDonald, Stuart W S

    2016-01-01

    Selection of a developmental time metric is useful for understanding causal processes that underlie aging-related cognitive change and for the identification of potential moderators of cognitive decline. Building on research suggesting that time to attrition is a metric sensitive to non-normative influences of aging (e.g., subclinical health conditions), we examined reason for attrition and intraindividual variability (IIV) in reaction time as predictors of cognitive performance. Three hundred and four community dwelling older adults (64-92 years) completed annual assessments in a longitudinal study. IIV was calculated from baseline performance on reaction time tasks. Multilevel models were fit to examine patterns and predictors of cognitive change. We show that time to attrition was associated with cognitive decline. Greater IIV was associated with declines on executive functioning and episodic memory measures. Attrition due to personal health reasons was also associated with decreased executive functioning compared to that of individuals who remained in the study. These findings suggest that time to attrition is a useful metric for representing cognitive change, and reason for attrition and IIV are predictive of non-normative influences that may underlie instances of cognitive loss in older adults.

  7. Attrition Bias in Panel Data: A Sheep in Wolf's Clothing? A Case Study Based on the Mabel Survey.

    Science.gov (United States)

    Cheng, Terence C; Trivedi, Pravin K

    2015-09-01

    This paper investigates the nature and consequences of sample attrition in a unique longitudinal survey of medical doctors. We describe the patterns of non-response and examine if attrition affects the econometric analysis of medical labour market outcomes using the estimation of physician earnings equations as a case study. We compare the econometric gestimates obtained from a number of different modelling strategies, which are as follows: balanced versus unbalanced samples; an attrition model for panel data based on the classic sample selection model; and a recently developed copula-based selection model. Descriptive evidence shows that doctors who work longer hours, have lower years of experience, are overseas trained and have changed their work location are more likely to drop out. Our analysis suggests that the impact of attrition on inference about the earnings of general practitioners is small. For specialists, there appears to be some evidence for an economically significant bias. Finally, we discuss how the top-up samples in the Medicine in Australia: Balancing Employment and Life survey can be used to address the problem of panel attrition. Copyright © 2015 John Wiley & Sons, Ltd.

  8. ART Attrition across Health Facilities Implementing Option B+ in Haiti.

    Science.gov (United States)

    Myrtil, Martine Pamphile; Puttkammer, Nancy; Gloyd, Stephen; Robinson, Julia; Yuhas, Krista; Domercant, Jean Wysler; Honoré, Jean Guy; Francois, Kesner

    2018-01-01

    Describing factors related to high attrition is important in order to improve the implementation of the Option B+ strategy in Haiti. We conducted a retrospective cohort study to describe the variability of antiretroviral therapy (ART) retention across health facilities among pregnant and lactating women and assess for differences in ART retention between Option B+ clients and other ART patients. There were 1989 Option B+ clients who initiated ART in 45 health facilities. The percentage of attrition varied from 9% to 81% across the facilities. The largest health facilities had 38% higher risk of attrition (relative risk [RR]: 1.38, 95% confidence interval [CI]: 1.08-1.77, P = .009). Private institutions had 18% less risk of attrition (RR: 0.82, 95% CI: 0.70-0.96, P = .020). Health facilities located in the West department and the South region had lower risk of attrition. Being on treatment in a large or public health facility or a facility located in the North region was a significant risk factor associated with high attrition among Option B+ clients. The implementation of the Option B+ strategy must be reevaluated in order to effectively eliminate mother-to-child HIV transmission.

  9. Attrition and bias in the MRC cognitive function and ageing study: an epidemiological investigation

    Directory of Open Access Journals (Sweden)

    Matthews Fiona E

    2004-04-01

    Full Text Available Abstract Background Any hypothesis in longitudinal studies may be affected by attrition and poor response rates. The MRC Cognitive Function and Ageing study (MRC CFAS is a population based longitudinal study in five centres with identical methodology in England and Wales each recruiting approximately 2,500 individuals. This paper aims to identify potential biases in the two-year follow-up interviews. Methods Initial non-response: Those not in the baseline interviews were compared in terms of mortality to those who were in the baseline interviews at the time of the second wave interviews (1993–1996. Longitudinal attrition: Logistic regression analysis was used to examine baseline differences between individuals who took part in the two-year longitudinal wave compared with those who did not. Results Initial non-response: Individuals who moved away after sampling but before baseline interview were 1.8 times more likely to die by two years (95% Confidence interval(CI 1.3–2.4 compared to respondents, after adjusting for age. The refusers had a slightly higher, but similar mortality pattern to responders (Odds ratio 1.2, 95%CI 1.1–1.4. Longitudinal attrition: Predictors for drop out due to death were being older, male, having impaired activities of daily living, poor self-perceived health, poor cognitive ability and smoking. Similarly individuals who refused were more likely to have poor cognitive ability, but had less years of full-time education and were more often living in their own home though less likely to be living alone. There was a higher refusal rate in the rural centres. Individuals who moved away or were uncontactable were more likely to be single, smokers, demented or depressed and were less likely to have moved if in warden-controlled accommodation at baseline. Conclusions Longitudinal estimation of factors mentioned above could be biased, particularly cognitive ability and estimates of movements from own home to residential homes

  10. Attrition and success rates of accelerated students in nursing courses: a systematic review.

    Science.gov (United States)

    Doggrell, Sheila Anne; Schaffer, Sally

    2016-01-01

    There is a comprehensive literature on the academic outcomes (attrition and success) of students in traditional/baccalaureate nursing programs, but much less is known about the academic outcomes of students in accelerated nursing programs. The aim of this systematic review is to report on the attrition and success rates (either internal examination or NCLEX-RN) of accelerated students, compared to traditional students. For the systematic review, the databases (Pubmed, Cinahl and PsychINFO) and Google Scholar were searched using the search terms 'accelerated' or 'accreditation for prior learning', 'fast-track' or 'top up' and 'nursing' with 'attrition' or 'retention' or 'withdrawal' or 'success' from 1994 to January 2016. All relevant articles were included, regardless of quality. The findings of 19 studies of attrition rates and/or success rates for accelerated students are reported. For international accelerated students, there were only three studies, which are heterogeneous, and have major limitations. One of three studies has lower attrition rates, and one has shown higher success rates, than traditional students. In contrast, another study has shown high attrition and low success for international accelerated students. For graduate accelerated students, most of the studies are high quality, and showed that they have rates similar or better than traditional students. Thus, five of six studies have shown similar or lower attrition rates. Four of these studies with graduate accelerated students and an additional seven studies of success rates only, have shown similar or better success rates, than traditional students. There are only three studies of non-university graduate accelerated students, and these had weaknesses, but were consistent in reporting higher attrition rates than traditional students. The paucity and weakness of information available makes it unclear as to the attrition and/or success of international accelerated students in nursing programs. The

  11. Limestone particle attrition and size distribution in a small circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Zhongxiang Chen; John R. Grace; C. Jim Lim [University of British Columbia, Vancouver, BC (Canada). Department of Chemical and Biological Engineering

    2008-06-15

    Limestone particle attrition was investigated in a small circulating fluidized bed reactor at temperatures from 25 to 850{sup o}C, 1 atm pressure and superficial gas velocities from 4.8 to 6.2 m/s. The effects of operating time, superficial gas velocity and temperature were studied with fresh limestone. No calcination or sulfation occurred at temperatures {le} 580{sup o}C, whereas calcination and sulfation affected attrition at 850{sup o}C. Increasing the temperature (while maintaining the same superficial gas velocity) reduced attrition if there was negligible calcination. Attrition was high initially, but after about 24 h, the rate of mass change became constant. The ratio of initial mean particle diameter to that at later times increased linearly with time and with (U{sub g} - U{sub mf}){sup 2}, while decreasing exponentially with temperature, with an activation energy for fresh limestone of -4.3 kJ/mol. The attrition followed Rittinger's surface theory. The change of surface area of limestone particles was proportional to the total excess kinetic energy consumed and to the total attrition time, whereas the change of surface area decreased exponentially with increasing temperature. At 850{sup o}C, the attrition rate of calcined lime was highest, whereas the attrition rate was lowest for sulfated particles. When online impact attrition was introduced, the attrition rate was about an order of magnitude higher than without impacts. 25 refs., 14 figs., 4 tabs.

  12. Obstacles to Success--Doctoral Student Attrition in South Africa

    Science.gov (United States)

    Herman, Chaya

    2011-01-01

    The article explores doctoral attrition in South Africa, investigating and comparing the attributions of attrition of doctoral students and PhD programme leaders. The article is based on secondary data analysis of two large studies on doctoral education in South Africa. The main point of the article is that the different understandings of the…

  13. Are Final Comments in Web Survey Panels Associated with Next-Wave Attrition?

    Directory of Open Access Journals (Sweden)

    Cynthia McLauchlan

    2016-12-01

    Full Text Available Near the end of a web survey respondents are often asked whether they have further comments. Such final comments are usually ignored, in part because open-ended questions are challenging to analyse. We explored whether final comments are associated with next-wave attrition in survey panels. We categorized a random sample of final comments in the Longitudinal Studies for the Social Sciences (LISS panel and Dutch Immigrant panel into one of eight categories (neutral, positive, six subcategories of negative and regressed the indicator of next-wave attrition on comment length, comment category and socio-demographic variables. In the Immigrant panel we found shorter final comments (55 words with decreased next-wave attrition relative to making no comment. Comments about unclear survey questions quadruple the odds of attrition and “other” (uncategorized negative comments almost double the odds of attrition. In the LISS panel, making a comment (vs. not and comment length are not associated with attrition. However, when specifying individual comment categories, neutral comments are associated with half the odds of attrition relative to not making a comment.

  14. Attrition of Tyee Formation Sandstone in a Natural Fluvial System

    Science.gov (United States)

    brandes, J. B.; Sanfilippo, J. D.; Lancaster, S. T.

    2013-12-01

    The data from this study will provide a rate of attrition with respect to change in volume, time and distance in a natural stream setting. Sandstone gravel attrition has been observed in previous studies with the use of rock tumblers, but measurements in natural systems are rare or absent. This study will use rocks with implanted passive integrated transponders (PIT) tags to track sediment movement. The study area is a natural mountain stream of approximately 4m width and 1m depth. This study is part of larger study of sediment transport. The rock volumes will be recorded prior to placement in an active channel using water displacement, the specific location along the channel will be recorded, and each tracer rock will be tracked using its individual radio frequency identification (RFID) number. Tracer rock deployment will occur before the annual high-water season. After one rainy season, the rocks will be located and removed from the stream using a radio frequency mobile radio frequency tracker. Their travel distances will be recorded and final volumes determined. Differences between initial and final volumes and travel distances will yield a distribution of attrition rates and, therefore, a mean gravel attrition rate.

  15. [Attrition and poor performance in general practice training: age, competence and knowledge play a role].

    Science.gov (United States)

    Vermeulen, Margit I; Kuyvenhoven, Marijke M; Zuithoff, N P A Peter; van der Graaf, Yolanda; Pieters, H M Ron

    2011-01-01

    To investigate which determinants are related to poor performance and forced attrition in the first year residency in general practice (GP). Observational retrospective cohort study. We collected data relating to personal characteristics such as age, sex and clinical experience from residents who started the GP training in Utrecht, the Netherlands, in the period March 2005-August 2007. We also collected competence scores from the domains 'medical expertise', 'doctor-patient communication' and 'professionalism', as well as scores on a national GP knowledge test. The outcome measures were 'poor performance' and 'forced attrition'. Multivariate logistic regression was used to analyse correlations between personal characteristics, competence scores on the 3 domains and knowledge scores in the first trimester on the one hand and poor performance or forced attrition on the other. 215 residents started the GP training. In the first trimester a quarter of the residents had an insufficient score in 1 or more of the domains. Competence scores were mutually correlated, but did not correlate with the knowledge score. 18 residents showed poor performance and 3 were forced to stop their training. Poor performance and forced attrition were correlated with age (adjusted odds ratio (OR): 1.1; 95% CI: 1.0-1.3), insufficient knowledge (adjusted OR: 8.9; 3.0-26.3) and medical expertise (adjusted OR: 2.1; 1.1-4.0) at the beginning of the training. Age, insufficient knowledge of general practice, and insufficient competence in the domain of 'medical expertise' at the beginning of the training are risk factors for poor performance by residents and attrition from their GP training.

  16. An Analysis of Recruit Training Attrition in the U.S. Marine Corps

    Science.gov (United States)

    1978-02-01

    Administration NR 170-819 I I. CONTROLLING OFFICE NAME AND ADDRESS It. ROILPORT CATS Organizational Effectiveness Research Programs February 1978 / Office of...for over 60% of the administrativo reasons for attrition. This finding underscores the importance of behavioral approaches to understanding and... controlled attrition may serve to confound individual level analyses of attrition. Although the R2 in this study is .10, this is not trivial. This

  17. Limestone fragmentation and attrition during fluidized bed oxyfiring

    Energy Technology Data Exchange (ETDEWEB)

    Fabrizio Scala; Piero Salatino [Istituto di Ricerche sulla Combustione - CNR, Napoli (Italy)

    2010-04-15

    Attrition/fragmentation of limestone under simulated fluidized bed oxyfiring conditions was investigated by means of an experimental protocol that had been previously developed for characterization of attrition/fragmentation of sorbents in air-blown atmospheric fluidized bed combustors. The protocol was based on the use of different and mutually complementary techniques. The extent and pattern of attrition by surface wear in the dense phase of a fluidized bed were assessed in experiments carried out with a bench scale fluidized bed combustor under simulated oxyfiring conditions. Sorbent samples generated during simulated oxyfiring tests were further characterized from the standpoint of fragmentation upon high velocity impact by means of a purposely designed particle impactor. Results showed that under calcination-hindered conditions attrition and fragmentation patterns are much different from those occurring under air-blown atmospheric combustion conditions. Noteworthy, attrition/fragmentation enhanced particle sulfation by continuously regenerating the exposed particle surface. 13 refs., 8 figs.

  18. Expectations and voluntary attrition in nursing students.

    Science.gov (United States)

    O'Donnell, Hugh

    2011-01-01

    This paper presents a series of findings generated during a larger study which aimed to develop a theoretical understanding of the reasons why nursing students voluntarily leave pre-registration nursing programmes. In this study, significant incongruence was found to exist between student expectations of pre-registration nursing programmes and the reality of these programmes following entry. The resulting dissonance was identified as an important factor in student decisions to voluntarily withdraw. A single case study design was selected to explore the causes of voluntary attrition in nursing students within a School of Nursing and Midwifery. The study population was obtained through purposeful sampling and consisted of 15 students who had previously voluntarily withdrawn from pre-registration nursing programmes. A semi-structured interview method was used to collect data from study participants. The interview schedule developed for use in the study reflected the key components of the conceptual model of higher education (HE) student attrition (Tinto, 1975, 1987, 1993). All interviews were tape recorded to facilitate later transcription. The Cyclical or Interactive Model of Qualitative Research (Miles and Huberman, 1994) was used to analyse data collected from study participants. This paper describes the unrealistic range of expectations which nursing students have of nursing, the information sources and experiences which inform student expectations and how ambiguous expectations contributed to voluntarily attrition. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Reducing Nursing Student Attrition: The Search for Effective Strategies

    Science.gov (United States)

    Kubec, Cathy

    2017-01-01

    This review of the literature summarizes recent exploration of nursing student attrition. Attrition places financial burdens on students who leave a program, results in lost revenue for the college, and compounds the existing nursing shortage. Some research investigated the student selection process, which seeks to decrease attrition by admitting…

  20. Attrition of undergraduate nursing students at selected South African universities

    Directory of Open Access Journals (Sweden)

    Erna Roos

    2016-08-01

    Full Text Available Background: The nursing profession forms the backbone of many healthcare systems. It therefore needs a consistent supply of registered nurses to deliver continuous and safe quality healthcare, and to replace the nurses leaving or retiring from the profession. Attrition actively occurs among nursing students in South Africa and threatens the future supply of registered nurses. Aim: The aim of the study was to describe the attrition rate at selected South African universities and the factors influencing undergraduate nursing students to discontinue their nursing studies at these universities. Method: A quantitative descriptive design was followed. Heads of the nursing departments at the selected universities captured data with a specifically designed questionnaire. Thereafter their former nursing students provided information via a structured telephonic interview on the reasons why they discontinued the nursing programme. Results: The study revealed that attrition of undergraduate nursing students for three intake years (2007, 2008 and 2009 at the participating universities was between 39.3% and 58.7%. Academic and financial reasons as well as poor wellness and health were the main causes for attrition. Another factor was failure to cope with the demands of the clinical environment. Conclusion: Attrition might not occur immediately when a nursing student is challenged, as the student might exploit the various types of support offered. Although some nursing students do benefit from the offered support, a large number of nursing students still discontinue the undergraduate nursing programme.

  1. Relative risk of home hemodialysis attrition in patients using a telehealth platform.

    Science.gov (United States)

    Weinhandl, Eric D; Collins, Allan J

    2017-12-06

    Home hemodialysis (HHD) facilitates increased treatment frequency, which may improve patient outcomes. However, attrition due to technique failure limits the clinical effectiveness of the modality. Nx2me Connected Health is a telehealth platform that enables ongoing assessment of HHD patients using NxStage equipment, and that may reduce patient burden. We aimed to assess whether use of Nx2me was associated with risk of HHD attrition. We compared risks of all-cause attrition, dialysis cessation (i.e., death or transplant), and technique failure in Nx2me users and matched control patients, using a retrospective cohort study. We also compared the likelihood of HHD training graduation in patients who initiated use of Nx2me during training with the likelihood in matched control patients. Matching factors included date of HHD initiation, NxStage treatment duration at initiation of follow-up, and prescribed treatment frequency. We used stratified Fine-Gray and Cox regression to compare risks, with adjustment for demographic factors and vascular access modality, and stratification by matched cluster. We identified 606 Nx2me users; 49.5% initiated use of Nx2me in NxStage equipment. Adjusted hazard ratios (AHRs) of all-cause attrition, dialysis cessation, and technique failure were 0.80 (95% confidence interval, 0.68-0.95), 1.10 (0.86-1.41), and 0.71 (0.57-0.87), respectively, for Nx2me users vs. matched controls. AHRs were similar in patients who initiated use of Nx2me in <3 months after initiation of HHD. The AHR of HHD training graduation was 1.61 (1.10-2.36) in patients who initiated use of Nx2me within 2 weeks of training initiation vs. matched controls. Use of Nx2me was associated with lower risk of all-cause attrition, lower risk of technique failure, and higher likelihood of HHD training graduation. Further studies are needed to identify the mechanisms by which use of a telehealth platform may improve clinical outcomes and reduce patient burden. © 2017 The Authors

  2. Clinical correlates of weight loss and attrition during a 10-week dietary intervention study

    DEFF Research Database (Denmark)

    Handjieva-Darlenska, Teodora; Holst, Claus; Grau, Katrine

    2012-01-01

    clinical centres in 7 European countries, who underwent a 10-week dietary intervention study comparing two hypo-energetic (-600 kcal/day) diets varying in fat content. Results: The multiple regression model showed that weight loss at week 10 was predicted by: 6.55 + 1.27 × early weight loss (kg) at week 1...... kg weight loss at week 5 emerged as an optimal predictor for reaching at least 10% weight loss at week 10. Greater attrition likelihood was predicted by high-fat diet, decreased early and half-way weight losses. Conclusion: Early and half-way weight losses are associated with and could contribute......Objective: The aim of this study was to identify the pre-treatment subject characteristics and weight loss changes as determinants of weight loss and attrition during a 10-week dietary intervention study. Methods: A total of 771 obese subjects (BMI 35.6 kg/m(2)) of both genders were included from 8...

  3. Understanding attrition from international Internet health interventions: a step towards global eHealth.

    Science.gov (United States)

    Geraghty, Adam W A; Torres, Leandro D; Leykin, Yan; Pérez-Stable, Eliseo J; Muñoz, Ricardo F

    2013-09-01

    Worldwide automated Internet health interventions have the potential to greatly reduce health disparities. High attrition from automated Internet interventions is ubiquitous, and presents a challenge in the evaluation of their effectiveness. Our objective was to evaluate variables hypothesized to be related to attrition, by modeling predictors of attrition in a secondary data analysis of two cohorts of an international, dual language (English and Spanish) Internet smoking cessation intervention. The two cohorts were identical except for the approach to follow-up (FU): one cohort employed only fully automated FU (n = 16 430), while the other cohort also used 'live' contact conditional upon initial non-response (n = 1000). Attrition rates were 48.1 and 10.8% for the automated FU and live FU cohorts, respectively. Significant attrition predictors in the automated FU cohort included higher levels of nicotine dependency, lower education, lower quitting confidence and receiving more contact emails. Participants' younger age was the sole predictor of attrition in the live FU cohort. While research on large-scale deployment of Internet interventions is at an early stage, this study demonstrates that differences in attrition from trials on this scale are (i) systematic and predictable and (ii) can largely be eliminated by live FU efforts. In fully automated trials, targeting the predictors we identify may reduce attrition, a necessary precursor to effective behavioral Internet interventions that can be accessed globally.

  4. Unemployment, the Great Recession, and Apprenticeship Attrition in the U.S.

    Science.gov (United States)

    Bilginsoy, Cihan

    2018-01-01

    The author estimates the impacts of the local rate of unemployment and the Great Recession on the quit and graduation rates of the U.S. construction trade apprentices over the 2001-2014 period. Trade union participation in training sponsorship had a strong influence on attrition rates. The impacts of the business cycle and the Great Recession on…

  5. Predictors of two forms of attrition in a longitudinal health study involving ageing participants: An analysis based on the Whitehall II study

    Directory of Open Access Journals (Sweden)

    Mein Gill

    2012-10-01

    Full Text Available Abstract Background Longitudinal studies are crucial providers of information about the needs of an ageing population, but their external validity is affected if partipants drop out. Previous research has identified older age, impaired cognitive function, lower educational level, living alone, fewer social activities, and lower socio-economic status as predictors of attrition. Methods This project examined attrition in participants of the Whitehall II study aged between 51–71 years, using data from questionnaires participants have completed biennially since 1985 when the study began. We examine the possibility of two distinct forms of attrition – non-response and formally requesting to withdraw – and whether they have different predictors. Potential predictors were age, gender, marital status, occupational grade, retirement, home ownership, presence of longstanding illness, SF-36 quality of life scores, social participation and educational level comparing participants and those who had withdrawn from the study. Results The two forms of attrition share many predictors and are associated but remain distinct. Being older, male, having a lower job grade, not being a home owner, not having a long standing illness, having higher levels of education, and not having retired, were all associated with a greater probability of non-response; being married was associated with higher probability in women and lower in men. Being older, male, having a lower job grade, not being a home owner, having lower SF-36 scores, taking part in fewer social activities, and not having a long standing illness, were all associated with greater probability of withdrawal. Conclusions The results suggest a strong gender effect on both routes not previously considered in analyses of attrition. Investigators of longitudinal studies should take measures to retain older participants and lower level socio-economic participants, who are more likely to cease participating

  6. Predictors of two forms of attrition in a longitudinal health study involving ageing participants: an analysis based on the Whitehall II study.

    Science.gov (United States)

    Mein, Gill; Johal, Suneeta; Grant, Robert L; Seale, Clive; Ashcroft, Richard; Tinker, Anthea

    2012-10-29

    Longitudinal studies are crucial providers of information about the needs of an ageing population, but their external validity is affected if partipants drop out. Previous research has identified older age, impaired cognitive function, lower educational level, living alone, fewer social activities, and lower socio-economic status as predictors of attrition. This project examined attrition in participants of the Whitehall II study aged between 51-71 years, using data from questionnaires participants have completed biennially since 1985 when the study began. We examine the possibility of two distinct forms of attrition--non-response and formally requesting to withdraw--and whether they have different predictors. Potential predictors were age, gender, marital status, occupational grade, retirement, home ownership, presence of longstanding illness, SF-36 quality of life scores, social participation and educational level comparing participants and those who had withdrawn from the study. The two forms of attrition share many predictors and are associated but remain distinct. Being older, male, having a lower job grade, not being a home owner, not having a long standing illness, having higher levels of education, and not having retired, were all associated with a greater probability of non-response; being married was associated with higher probability in women and lower in men. Being older, male, having a lower job grade, not being a home owner, having lower SF-36 scores, taking part in fewer social activities, and not having a long standing illness, were all associated with greater probability of withdrawal. The results suggest a strong gender effect on both routes not previously considered in analyses of attrition. Investigators of longitudinal studies should take measures to retain older participants and lower level socio-economic participants, who are more likely to cease participating. Recognition should be given to the tendency for people with health problems to be

  7. Posttreatment attrition and its predictors, attrition bias, and treatment efficacy of the anxiety online programs.

    Science.gov (United States)

    Al-Asadi, Ali M; Klein, Britt; Meyer, Denny

    2014-10-14

    Although relatively new, the field of e-mental health is becoming more popular with more attention given to researching its various aspects. However, there are many areas that still need further research, especially identifying attrition predictors at various phases of assessment and treatment delivery. The present study identified the predictors of posttreatment assessment completers based on 24 pre- and posttreatment demographic and personal variables and 1 treatment variable, their impact on attrition bias, and the efficacy of the 5 fully automated self-help anxiety treatment programs for generalized anxiety disorder (GAD), social anxiety disorder (SAD), panic disorder with or without agoraphobia (PD/A), obsessive-compulsive disorder (OCD), and posttraumatic stress disorder (PTSD). A complex algorithm was used to diagnose participants' mental disorders based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision; DSM-IV-TR). Those who received a primary or secondary diagnosis of 1 of 5 anxiety disorders were offered an online 12-week disorder-specific treatment program. A total of 3199 individuals did not formally drop out of the 12-week treatment cycle, whereas 142 individuals formally dropped out. However, only 347 participants who completed their treatment cycle also completed the posttreatment assessment measures. Based on these measures, predictors of attrition were identified and attrition bias was examined. The efficacy of the 5 treatment programs was assessed based on anxiety-specific severity scores and 5 additional treatment outcome measures. On average, completers of posttreatment assessment measures were more likely to be seeking self-help online programs; have heard about the program from traditional media or from family and friends; were receiving mental health assistance; were more likely to learn best by reading, hearing and doing; had a lower pretreatment Kessler-6 total score; and were older

  8. Attrition in the Austrian Generations and Gender Survey: Is there a bias by fertility-relevant aspects?

    Directory of Open Access Journals (Sweden)

    Isabella Buber-Ennser

    2014-08-01

    Full Text Available Background: In longitudinal research the loss of sample members between waves is a possible source of bias. It is therefore crucial to analyse attrition. Objective: This paper analyses attrition in a longitudinal study on family and fertility, by distinguishing between attrition due to non-contact and attrition due to non-cooperation. Methods: Based on the first two waves of the Austrian Generations and Gender Survey, the two components of attrition are studied separately by using bivariate as well as multivariate methods. Moreover, overall dropout - the combination of both components - isanalysed. Apart from various socio-economic characteristics and data collection information, the study focuses on fertility-relevant variables such as fecundity, fertility intentions, sexual orientation, and traditional attitudes. Results: Fecundity, fertility intentions, and homosexual relationships are associated with higher attrition due to non-cooperation in bivariate analyses, but have no explanatory power inthe multivariate model. Pregnancy and traditional attitudes towards marriage are associated with significantly lower attrition due to non-cooperation in the multivariate context. Overall dropout is significantly lower only among persons with traditionalattitudes towards marriage, although small in size and statistical significance. Moreover, various individual and regional characteristics are significantly associated with dropout, with differences between attrition due to non-contact and attrition due to non-cooperation. Conclusions: Detailed insights into attrition are not only important when using longitudinal data and interpreting results, but also for the design of future data collections. The Austrian GGS panel has a relatively low dropout (22Š and is affected by a small bias towards familyoriented persons as well as less-educated respondents and persons with migrationbackgrounds, but the data can be used without concern about selectivity.

  9. Evolutionary dynamics of a smoothed war of attrition game.

    Science.gov (United States)

    Iyer, Swami; Killingback, Timothy

    2016-05-07

    In evolutionary game theory the War of Attrition game is intended to model animal contests which are decided by non-aggressive behavior, such as the length of time that a participant will persist in the contest. The classical War of Attrition game assumes that no errors are made in the implementation of an animal׳s strategy. However, it is inevitable in reality that such errors must sometimes occur. Here we introduce an extension of the classical War of Attrition game which includes the effect of errors in the implementation of an individual׳s strategy. This extension of the classical game has the important feature that the payoff is continuous, and as a consequence admits evolutionary behavior that is fundamentally different from that possible in the original game. We study the evolutionary dynamics of this new game in well-mixed populations both analytically using adaptive dynamics and through individual-based simulations, and show that there are a variety of possible outcomes, including simple monomorphic or dimorphic configurations which are evolutionarily stable and cannot occur in the classical War of Attrition game. In addition, we study the evolutionary dynamics of this extended game in a variety of spatially and socially structured populations, as represented by different complex network topologies, and show that similar outcomes can also occur in these situations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Attrition resistant Fischer-Tropsch catalyst and support

    Science.gov (United States)

    Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

    2004-05-25

    A catalyst support having improved attrition resistance and a catalyst produced therefrom. The catalyst support is produced by a method comprising the step of treating calcined .gamma.-alumina having no catalytic material added thereto with an acidic aqueous solution having an acidity level effective for increasing the attrition resistance of the calcined .gamma.-alumina.

  11. Factors Associated with Veterinary Clinical Faculty Attrition.

    Science.gov (United States)

    Furr, Martin

    Faculty attrition and recruitment for veterinary clinical faculty positions have been reported as significant problems in veterinary medical education. To investigate the factors that may be important in veterinary clinical faculty retention, the perceptions and views of veterinary clinical academic faculty were determined using a web-distributed electronic survey. Responses were dichotomized by whether the respondent had or had not left an academic position and were analyzed for their association with faculty attrition. A total of 1,226 responses were recorded, and results demonstrated that factors other than compensation were associated with veterinary clinical faculty attrition, including departmental culture, work-life balance, and recognition and support of clinical medicine by the administration. Forty-four percent of respondents who had held a faculty appointment reported leaving academia either voluntarily or for non-voluntary reasons such as failure to achieve tenure, retirement, or having their position closed. Attention to correcting deficiencies in workplace culture and professional rewards could be a beneficial means by which to decrease the faculty attrition rates currently observed in clinical academic veterinary medicine.

  12. Incorporating direct marketing activity into latent attrition models

    NARCIS (Netherlands)

    Schweidel, David A.; Knox, George

    2013-01-01

    When defection is unobserved, latent attrition models provide useful insights about customer behavior and accurate forecasts of customer value. Yet extant models ignore direct marketing efforts. Response models incorporate the effects of direct marketing, but because they ignore latent attrition,

  13. Self-esteem and self-efficacy as predictors of attrition in associate degree nursing students.

    Science.gov (United States)

    Peterson-Graziose, Virginia; Bryer, Jennifer; Nikolaidou, Maria

    2013-06-01

    There is a serious and growing shortage of nurses in the United States, and the high rate of student attrition from nursing programs has further added to this problem. The challenge for schools of nursing is to recruit increased numbers of qualified candidates into their programs and to determine ways to decrease the rate of student attrition. The purpose of this study was to determine whether self-esteem, self-efficacy, and life stressors were significantly related to student attrition in first-semester associate degree nursing students. A descriptive correlational design and nonprobability convenience sample of first-semester associate degree nursing students was used. Data were gathered using the Rosenberg Self-Esteem Scale, the General Self-Efficacy Scale, and the Holmes and Rahe Social Readjustment Rating Scale. Findings indicated that self-esteem was significantly associated with student attrition. Results from this study provide the basis for targeted interventions designed to decrease student attrition rates in associate degree nursing programs. Copyright 2013, SLACK Incorporated.

  14. Teacher Attrition in the USA: The Relational Elements in a Utah Case Study

    Science.gov (United States)

    Newberry, Melissa; Allsop, Yvonne

    2017-01-01

    Previous work on teacher attrition in the US has indicated that those who stay in the profession and those who leave are not separate homogenous groups. In this study, the lived experience of former teachers is examined to determine the issues that distinguish leavers from stayers. The sample is from the state of Utah, a state with one of the…

  15. Attrition in a 30-year follow-up of a perinatal birth risk cohort: factors change with age

    Directory of Open Access Journals (Sweden)

    Jyrki Launes

    2014-07-01

    Full Text Available Background. Attrition is a major cause of potential bias in longitudinal studies and clinical trials. Attrition rate above 20% raises concern of the reliability of the results. Few studies have looked at the factors behind attrition in follow-ups spanning decades.Methods. We analyzed attrition and associated factors of a 30-year follow-up cohort of subjects who were born with perinatal risks for neurodevelopmental disorders. Attrition rates were calculated at different stages of follow-up and differences between responders and non-responders were tested. To find combinations of variables influencing attrition and investigate their relative importance at birth, 5, 9, 16 and 30 years of follow-up we used the random forest classification.Results. Initial loss of potential participants was 13%. Attrition was 16% at five, 24% at nine, 35% at 16 and 46% at 30 years. The only group difference that emerged between responders and non-responders was in socioeconomic status (SES. The variables identified by random forest classification analysis were classified into Birth related, Development related and SES related. Variables from all these categories contributed to attrition, but SES related variables were less important than birth and development associated variables. Classification accuracy ranged between 0.74 and 0.96 depending on age.Discussion. Lower SES is linked to attrition in many studies. Our results point to the importance of the growth and development related factors in a longitudinal study. Parents’ decisions to participate depend on the characteristics of the child. The same association was also seen when the child, now grown up, decided to participate at 30 years. In addition, birth related medical variables are associated with the attrition still at the age of 30. Our results using a data mining approach suggest that attrition in longitudinal studies is influenced by complex interactions of a multitude of variables, which are not

  16. Factors related to attrition from trauma-focused cognitive behavioral therapy.

    Science.gov (United States)

    Wamser-Nanney, Rachel; Steinzor, Cazzie E

    2017-04-01

    Attrition from child trauma-focused treatments such as Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) is common; yet, the factors of children who prematurely terminate are unknown. The aim of the current study was to identify risk factors for attrition from TF-CBT. One hundred and twenty-two children (ages 3-18; M=9.97, SD=3.56; 67.2% females; 50.8% Caucasian) who received TF-CBT were included in the study. Demographic and family variables, characteristics of the trauma, and caregiver- and child-reported pretreatment symptoms levels were assessed in relation to two operational definitions of attrition: 1) clinician-rated dropout, and 2) whether the child received an adequate dose of treatment (i.e., 12 or more sessions). Several demographic factors, number of traumatic events, and children's caregiver-rated pretreatment symptoms were related to clinician-rated dropout. Fewer factors were associated with the adequate dose definition. Child Protective Services involvement, complex trauma exposure, and child-reported pretreatment trauma symptoms were unrelated to either attrition definition. Demographics, trauma characteristics, and level of caregiver-reported symptoms may help to identify clients at risk for premature termination from TF-CBT. Clinical and research implications for different operational definitions and suggestions for future work will be presented. Published by Elsevier Ltd.

  17. Particle Separation of Non-Decontamination Soil using Attrition and Washing

    International Nuclear Information System (INIS)

    Koo, Daeseo; Sung, Hyun-Hee; Kim, Seung-Soo; Hong, Sang Bum; Seo, Bum Kyoung; Choi, Jong-Won

    2017-01-01

    In this study, to improve the decontamination efficiency of uranium soil, a preliminary experiment on the particle separation of non-decontamination soil was carried out using attrition and washing. The characteristics of the attrition and washing system are investigated. A conditional experiment on particle separation of non-decontamination soil will be performed. A preliminary experiment on the particle separation of non-decontamination soil was carried out to improve the decontamination efficiency of uranium soil. This experiment was performed with the ratio of soil to water (1:4) for the particle separation of non-decontamination soil. The operations of all equipment such as attrition scrubber, ultrasonic reaction, vibrating screen, and hydro-cyclone were conducted and confirmed. In the future, the additional experiments will be conducted for optimal experimental condition.

  18. Factors affecting attrition from associate degree nursing programs in North Carolina.

    Science.gov (United States)

    Fraher, Erin; Belsky, Daniel W; Gaul, Katie; Carpenter, Jessica

    2010-01-01

    Projected nursing shortfalls have spurred the state of North Carolina to initiate a series of strategies to increase the number of graduates from pre-licensure Registered Nurse (RN) programs. These efforts have been largely successful, but attrition rates from Associate Degree Nursing (ADN) programs remain high. Only 58% of students entering ADN programs complete the degree. While policy makers are keenly aware that attrition from ADN programs is problematic, there is a lack of empirical evidence to identify the specific factors contributing to student attrition. In late 2007, the North Carolina Community College System (NCCCS) asked the Cecil G. Sheps Center for Health Services Research to conduct a study of Associate Degree Nursing program attrition and its causes. This paper summarizes the findings from that study and identifies the student- and program-level characteristics associated with more and less successful ADN programs. While this study was conducted in a single state in the US, the substantive findings--as well as the methodological approach--may be useful to other states and other countries. The study revealed that socioeconomically disadvantaged students (those with GEDs and those who received Pell Grants), non-white students, and younger and older students were less likely to graduate on-time. When programs were grouped into high and low performance categories on the basis of risk adjusted graduation rates, high performing programs were distinguished by more stringent admissions policies and better educated faculties. Nursing shortages have garnered significant attention and resources from state and national workforce planners in recent years. But to date, investments in expanding program capacity have not been matched by attention to program completion rates, with the result that we have enlarged the pipeline without fixing the leaks. Faculty shortages and recession-induced resource constraints limit further program expansion. Addressing attrition

  19. The implications of selective attrition for estimates of intergenerational elasticity of family income.

    Science.gov (United States)

    Schoeni, Robert F; Wiemers, Emily E

    2015-09-01

    Numerous studies have estimated a high intergenerational correlation in economic status. Such studies do not typically attend to potential biases that may arise due to survey attrition. Using the Panel Study of Income Dynamics - the data source most commonly used in prior studies - we demonstrate that attrition is particularly high for low-income adult children with low-income parents and particularly low for high-income adult children with high-income parents. Because of this pattern of attrition, intergenerational upward mobility has been overstated for low-income families and downward mobility has been understated for high-income families. The bias among low-income families is greater than the bias among high-income families implying that intergenerational elasticity in family income is higher than previous estimates with the Panel Study of Income Dynamics would suggest.

  20. Travel time and attrition from VHA care among women veterans: how far is too far?

    Science.gov (United States)

    Friedman, Sarah A; Frayne, Susan M; Berg, Eric; Hamilton, Alison B; Washington, Donna L; Saechao, Fay; Maisel, Natalya C; Lin, Julia Y; Hoggatt, Katherine J; Phibbs, Ciaran S

    2015-04-01

    Travel time, an access barrier, may contribute to attrition of women veterans from Veterans Health Administration (VHA) care. We examined whether travel time influences attrition: (a) among women veterans overall, (b) among new versus established patients, and (c) among rural versus urban patients. This retrospective cohort study used logistic regression to estimate the association between drive time and attrition, overall and for new/established and rural/urban patients. In total, 266,301 women veteran VHA outpatients in the Fiscal year 2009. An "attriter" did not return for VHA care during the second through third years after her first 2009 visit (T0). Drive time (log minutes) was between the patient's residence and her regular source of VHA care. "New" patients had no VHA visits within 3 years before T0. Models included age, service-connected disability, health status, and utilization as covariates. Overall, longer drive times were associated with higher odds of attrition: drive time adjusted odds ratio=1.11 (99% confidence interval, 1.09-1.14). The relationship between drive time and attrition was stronger among new patients but was not modified by rurality. Attrition among women veterans is sensitive to longer drive time. Linking new patients to VHA services designed to reduce distance barriers (telemedicine, community-based clinics, mobile clinics) may reduce attrition among women new to VHA.

  1. Patient attrition from the HIV antiretroviral therapy program at two hospitals in Haiti.

    Science.gov (United States)

    Puttkammer, Nancy H; Zeliadt, Steven B; Baseman, Janet G; Destiné, Rodney; Wysler Domerçant, Jean; Labbé Coq, Nancy Rachel; Atwood Raphael, Nernst; Sherr, Kenneth; Tegger, Mary; Yuhas, Krista; Barnhart, Scott

    2014-10-01

    To identify factors associated with antiretroviral therapy (ART) attrition among patients initiating therapy in 2005-2011 at two large, public-sector department-level hospitals, and to inform interventions to improve ART retention. This retrospective cohort study used data from the iSanté electronic medical record (EMR) system. The study characterized ART attrition levels and explored the patient demographic, clinical, temporal, and service utilization factors associated with ART attrition, using time-to-event analysis methods. Among the 2 023 patients in the study, ART attrition on average was 17.0 per 100 person-years (95% confidence interval (CI): 15.8-18.3). In adjusted analyses, risk of ART attrition was up to 89% higher for patients living in distant communes compared to patients living in the same commune as the hospital (hazard ratio: 1.89, 95%CI: 1.54-2.33; P Hospital site, earlier year of ART start, spending less time enrolled in HIV care prior to ART initiation, receiving a non-standard ART regimen, lacking counseling prior to ART initiation, and having a higher body mass index were also associated with attrition risk. The findings suggest quality improvement interventions at the two hospitals, including: enhanced retention support and transportation subsidies for patients accessing care from remote areas; counseling for all patients prior to ART initiation; timely outreach to patients who miss ART pick-ups; "bridging services" for patients transferring care to alternative facilities; routine screening for anticipated interruptions in future ART pick-ups; and medical case review for patients placed on non-standard ART regimens. The findings are also relevant for policymaking on decentralization of ART services in Haiti.

  2. Does Coordinated, Multidisciplinary Treatment Limit Medical Disability and Attrition Related to Spine Conditions in the US Navy?

    Science.gov (United States)

    Ziemke, Gregg; Campello, Marco; Hiebert, Rudi; Weiner, Shira Schecter; Rennix, Chris; Nordin, Margareta

    2015-09-01

    Musculoskeletal conditions account for the largest proportion of cases resulting in early separation from the US Navy. This study evaluates the impact of the Spine Team, a multidisciplinary care group that included physicians, physical therapists, and a clinical psychologist, for the treatment of active-duty service members with work-disabling, nonspecific low back pain at the Naval Medical Center, Portsmouth, VA, USA. We compared the impact of the introduction of the Spine Team in limiting disability and attrition from work-disabling spine conditions with the experience of the Naval Medical Center, San Diego, CA, USA, where there is no comparable spine team. Is a multidisciplinary spine team effective in limiting disability and attrition related to work-disabling spine conditions as compared with the current standard of care for US military active-duty service members? This is a retrospective, pre-/post-study with a separate, concurrent control group using administratively collected data from two large military medical centers during the period 2007 to 2009. In this study, disability is expressed as the proportion of active-duty service members seeking treatment for a work-disabling spine condition that results in the assignment of a first-career limited-duty status. Attrition is expressed as the proportion of individuals assigned a first-career limited-duty status for a work-disabling spine condition who were referred to a Physical Evaluation Board. We analyzed 667 individuals assigned a first-career limited-duty for a work-disabling spine condition between 2007 and 2009 who received care at the Naval Medical Center Portsmouth or Naval Medical Center San Diego. Rates of first-career limited-duty assignments for spine conditions decreased from 2007 to 2009 at both sites, but limited-duty rates decreased to a greater extent at the intervention site (Naval Medical Center Portsmouth; from 8.5 per 100 spine cases in 2007 to 5.1 per 100 cases in 2009, p Team was

  3. Confusing similar words: ERP correlates of lexical-semantic processing in first language attrition and late second language acquisition.

    Science.gov (United States)

    Kasparian, Kristina; Steinhauer, Karsten

    2016-12-01

    First language (L1) attrition is a socio-linguistic circumstance where second language (L2) learning coincides with changes in exposure and use of the native-L1. Attriters often report experiencing a decline in automaticity or proficiency in their L1 after a prolonged period in the L2 environment, while their L2 proficiency continues to strengthen. Investigating the neurocognitive correlates of attrition alongside those of late L2 acquisition addresses the question of whether the brain mechanisms underlying both L1 and L2 processing are strongly determined by proficiency, irrespective of whether the language was acquired from birth or in adulthood. Using event-related-potentials (ERPs), we examined lexical-semantic processing in Italian L1 attriters, compared to adult Italian L2 learners and to Italian monolingual native speakers. We contrasted the processing of classical lexical-semantic violations (Mismatch condition) with sentences that were equally semantically implausible but arguably trickier, as the target-noun was "swapped" with an orthographic neighbor that differed only in its final vowel and gender-marking morpheme (e.g., cappello (hat) vs. cappella (chapel)). Our aim was to determine whether sentences with such "confusable nouns" (Swap condition) would be processed as semantically correct by late L2 learners and L1 attriters, especially for those individuals with lower Italian proficiency scores. We found that lower-proficiency Italian speakers did not show significant N400 effects for Swap violations relative to correct sentences, regardless of whether Italian was the L1 or the L2. Crucially, N400 response profiles followed a continuum of "nativelikeness" predicted by Italian proficiency scores - high-proficiency attriters and high-proficiency Italian learners were indistinguishable from native controls, whereas attriters and L2 learners in the lower-proficiency range showed significantly reduced N400 effects for "Swap" errors. Importantly, attriters

  4. Are pilot trials useful for predicting randomisation and attrition rates in definitive studies: A review of publicly funded trials

    Science.gov (United States)

    Whitehead, Amy; Pottrill, Edward; Julious, Steven A; Walters, Stephen J

    2018-01-01

    Background/aims: External pilot trials are recommended for testing the feasibility of main or confirmatory trials. However, there is little evidence that progress in external pilot trials actually predicts randomisation and attrition rates in the main trial. To assess the use of external pilot trials in trial design, we compared randomisation and attrition rates in publicly funded randomised controlled trials with rates in their pilots. Methods: Randomised controlled trials for which there was an external pilot trial were identified from reports published between 2004 and 2013 in the Health Technology Assessment Journal. Data were extracted from published papers, protocols and reports. Bland–Altman plots and descriptive statistics were used to investigate the agreement of randomisation and attrition rates between the full and external pilot trials. Results: Of 561 reports, 41 were randomised controlled trials with pilot trials and 16 met criteria for a pilot trial with sufficient data. Mean attrition and randomisation rates were 21.1% and 50.4%, respectively, in the pilot trials and 16.8% and 65.2% in the main. There was minimal bias in the pilot trial when predicting the main trial attrition and randomisation rate. However, the variation was large: the mean difference in the attrition rate between the pilot and main trial was −4.4% with limits of agreement of −37.1% to 28.2%. Limits of agreement for randomisation rates were −47.8% to 77.5%. Conclusion: Results from external pilot trials to estimate randomisation and attrition rates should be used with caution as comparison of the difference in the rates between pilots and their associated full trial demonstrates high variability. We suggest using internal pilot trials wherever appropriate. PMID:29361833

  5. Australian aboriginal tooth succession, interproximal attrition, and Begg's theory.

    Science.gov (United States)

    Corruccini, R S

    1990-04-01

    In 1954, P.R. Begg analyzed interproximal attrition as a prehistorically universal mechanism to reduce tooth size. With modern processed diets and the virtual disappearance of constant interproximal attrition, Begg asserted, teeth remain too large for the arches and become crowded. Later investigators have questioned Begg's estimate of attritional tooth-size reduction, as well as aspects of his theory relating the succession sequence of permanent teeth to different malocclusions. The present paper examines the theory using longitudinal casts and records of modern Australian aborigines who are among the first generation lacking notable interproximal attrition thanks to a "modernized" diet. Deciduous and permanent tooth size, arch size, and occlusal relational variables were analyzed with respect to the expected occlusal outcomes in the absence of attritional tooth reduction. Permanent incisor overjet correlated with crowding status, as predicted by Begg. On the other hand, longer teeth did not relate to crowding in general nor to crowding in relevant local areas or during developmental stages. Unfavorable leeway space did not relate clearly to crowding or other malocclusions. Lowered correlations among structures and narrowness of the maxilla related more significantly to malocclusion. These results are in keeping with recent thinking that small jaws rather than large teeth underlie tooth/arch discrepancy.

  6. Patient attrition from the HIV antiretroviral therapy program at two hospitals in Haiti

    Directory of Open Access Journals (Sweden)

    Nancy H. Puttkammer

    2014-10-01

    Full Text Available OBJECTIVE: To identify factors associated with antiretroviral therapy (ART attrition among patients initiating therapy in 2005-2011 at two large, public-sector department-level hospitals, and to inform interventions to improve ART retention. METHODS: This retrospective cohort study used data from the iSanté electronic medical record (EMR system. The study characterized ART attrition levels and explored the patient demographic, clinical, temporal, and service utilization factors associated with ART attrition, using time-to-event analysis methods. RESULTS: Among the 2 023 patients in the study, ART attrition on average was 17.0 per 100 person-years (95% confidence interval (CI: 15.8-18.3. In adjusted analyses, risk of ART attrition was up to 89% higher for patients living in distant communes compared to patients living in the same commune as the hospital (hazard ratio: 1.89, 95%CI: 1.54-2.33; P < 0.001. Hospital site, earlier year of ART start, spending less time enrolled in HIV care prior to ART initiation, receiving a non-standard ART regimen, lacking counseling prior to ART initiation, and having a higher body mass index were also associated with attrition risk. CONCLUSIONS: The findings suggest quality improvement interventions at the two hospitals, including: enhanced retention support and transportation subsidies for patients accessing care from remote areas; counseling for all patients prior to ART initiation; timely outreach to patients who miss ART pick-ups; "bridging services" for patients transferring care to alternative facilities; routine screening for anticipated interruptions in future ART pick-ups; and medical case review for patients placed on non-standard ART regimens. The findings are also relevant for policymaking on decentralization of ART services in Haiti.

  7. The management of over closured anterior teeth due to attrition

    Directory of Open Access Journals (Sweden)

    Eha Djulaeha

    2009-12-01

    Full Text Available Background: Tooth is the hardest tissue in human body, that can be injured because of attrition process. For old people, denture attrition process is caused by psysiological process relating with the mastication function which also supported by some bad habits such an bruxism, premature contact, and consuming habit of abrasive food. Attrition or abrasion can also be happened with patien’t dentition who does not have teeth subtutition for long time due the lost of their maxillary as well as mandibulary. The pasient will loose their vertical dimension of occlusion, injure, and the lower jaw becomes over closed which is called over closure. Purpose: This article reported the management of over closured anterior teeth due to attrition. Case: a seventy six year old woman patient came to Prosthodontic Clinic in Faculty of Dentistry, Airlangga University, to rehabilitate her upper and lower severe attrited anterior teeth and her posterior teeth. The patient has experienced of wearing acrylic removable mandibular partial denture ten years ago. Unfortunaly, the denture was uncomfortable, and she did not wear it anymore since five years ago. Case management: The severe attrition of anterior teeth with the lost of occlusal vertical dimension can be treated by improving the occlusal vertical dimension gradually. The treatment is then followed by the increasing of the height of the anterior teeth by lengthening the crown teeth of upper jaw with 12 units of span bridge and the acrylic removable partial denture of lower jaw. Conclusion: The severe attrition of anterior teeth with the lost of occlusal vertical dimension can be treated by improving the occlusal vertical dimension gradually, using long span bridge and acrylic removable partial denture.

  8. No differential attrition was found in randomized controlled trials published in general medical journals: a meta-analysis.

    Science.gov (United States)

    Crutzen, Rik; Viechtbauer, Wolfgang; Kotz, Daniel; Spigt, Mark

    2013-09-01

    Differential attrition is regarded as a major threat to the internal validity of a randomized controlled trial (RCT). This study identifies the degree of differential attrition in RCTs covering a broad spectrum of clinical areas and factors that are related to this. A PubMed search was conducted to obtain a random sample of 100 RCTs published between 2008 and 2010 in journals from the ISI Web of Knowledge(SM) category of medicine, general and internal. Eligibility criteria for selecting studies were primary publications of two-arm parallel randomized clinical trials, containing human participants and one or multiple follow-up measurements whose availability depended on the patients' willingness to participate. A significant amount of differential attrition was observed in 8% of the trials. The average differential attrition rate was 0.99 (95% confidence interval: 0.97-1.01), indicating no general difference in attrition rates between intervention and control groups. Moreover, no indication of heterogeneity was found, suggesting that the occurrence of differential attrition in the published literature is mostly a chance finding, unrelated to any particular design factors. Differential attrition did not generally occur in RCTs covering a broad spectrum of clinical areas within general and internal medicine. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. The management of over closured anterior teeth due to attrition

    OpenAIRE

    Eha Djulaeha; Sukaedi Sukaedi

    2009-01-01

    Background: Tooth is the hardest tissue in human body, that can be injured because of attrition process. For old people, denture attrition process is caused by psysiological process relating with the mastication function which also supported by some bad habits such an bruxism, premature contact, and consuming habit of abrasive food. Attrition or abrasion can also be happened with patien’t dentition who does not have teeth subtutition for long time due the lost of their maxillary as well as ma...

  10. Attitudes towards attrition among UK trainees in obstetrics and gynaecology.

    Science.gov (United States)

    Gafson, Irene; Currie, Jane; O'Dwyer, Sabrina; Woolf, Katherine; Griffin, Ann

    2017-06-02

    Physician dissatisfaction in the workplace has consequences for patient safety. Currently in the UK, 1 in 5 doctors who enter specialist training in obstetrics and gynaecology leave the programme before completion. Trainee attrition has implications for workforce planning, organization of health-care services and patient care. The authors conducted a survey of current trainees' and former trainees' views concerning attrition and 'peri-attrition' - a term coined to describe the trainee who has seriously considered leaving the specialty. The authors identified six key themes which describe trainees' feelings about attrition in obstetrics and gynaecology: morale and undermining; training processes and paperwork; support and supervision; work-life balance and realities of life; NHS environment; and job satisfaction. This article discusses themes of an under-resourced health service, bullying, lack of work-life balance and poor personal support.

  11. Workshop on Language Student Attrition

    National Research Council Canada - National Science Library

    Whelan, Bree

    2001-01-01

    Seventy individuals from Government agencies (military and civilian), academia, and contractor organizations attended all or parts of a Workshop on student Attrition held at the Defense Language Institute Foreign Language Center (DLIFLC...

  12. Pilot Testing for Feasibility in a Study of Student Retention and Attrition in Online Undergraduate Programs

    Science.gov (United States)

    Fraser, Joy; Fahlman, Dorothy; Arscott, Jane; Guillot, Isabelle

    2018-01-01

    Prior to undertaking a descriptive study on attrition and retention of students in two online undergraduate health administration and human service programs, a pilot test was conducted to assess the procedures for participant recruitment, usability of the survey questionnaire, and data collection processes. A retention model provided the…

  13. Attrition and Rape Case Characteristics: A Profile and Comparison of Female Sex Workers and Non-Sex Workers.

    Science.gov (United States)

    Lea, Susan J; Callaghan, Lynne; Grafton, Iain; Falcone, M Aurora; Shaw, Steve

    2016-07-01

    The attrition of rape cases from the criminal justice system (CJS) remains high and there is a paucity of research in relation to marginalized groups. Sex workers (SWs) are vulnerable to sexual violence due to the nature of their work. They are also unlikely to report such violence to police for a range of reasons. Two stages of research sought to describe the victim, perpetrator, and offense characteristics of SW rape and to examine the attrition of these cases. All rapes and attempted rapes (N = 1,146) reported to police in a large city in the South West of England over a 21-year period were examined; 67 cases involved SWs. Data were extracted from police files in line with the variables of interest. Secondary analysis of the total number of SW rapes (n = 67) resulted in a profile of these cases. A matched pairs study revealed significant differences in victim, perpetrator, and assault characteristics between SW (n = 62) and non-sex-worker (NSW) samples (n = 62). Although no significant difference was found in terms of attrition from the CJS, SW cases were observed to secure more convictions for rape than NSW cases. The implications of the findings for practice and future research are discussed. © The Author(s) 2015.

  14. Team-Based Learning Reduces Attrition in a First-Semester General Chemistry Course

    Science.gov (United States)

    Comeford, Lorrie

    2016-01-01

    Team-based learning (TBL) is an instructional method that has been shown to reduce attrition and increase student learning in a number of disciplines. TBL was implemented in a first-semester general chemistry course, and its effect on attrition was assessed. Attrition from sections before implementing TBL (fall 2008 to fall 2009) was compared with…

  15. Military Personnel Attrition and Retention: Research in Progress

    Science.gov (United States)

    1981-10-01

    NATIONAL ANALYSES OF ATTRITION 13 H. Wallace Sinaiko and Kenneth C. Scheflen AIR FORCE ATTRITION RESEARCH: ANALISIS OF PRE- AND POST- 15 ENLISTMENT FACTORS...are specific types ot codes used, to icdentity categories of reenlistments, extensions, and losses. These SPD codes will be clustered in various ways...two enlistment terms in the Navy. The Navy’s 110 ratings were grouped into 24 occupational tields which represented clusters of similar skills, similar

  16. Factors associated with study attrition in a pilot randomised controlled trial to explore the role of exercise-assisted reduction to stop (EARS) smoking in disadvantaged groups.

    Science.gov (United States)

    Thompson, T P; Greaves, C J; Ayres, R; Aveyard, P; Warren, F C; Byng, R; Taylor, R S; Campbell, J L; Ussher, M; Michie, S; West, R; Taylor, A H

    2016-10-27

    Study attrition has the potential to compromise a trial's internal and external validity. The aim of the present study was to identify factors associated with participant attrition in a pilot trial of the effectiveness of a novel behavioural support intervention focused on increasing physical activity to reduce smoking, to inform the methods to reduce attrition in a definitive trial. Disadvantaged smokers who wanted to reduce but not quit were randomised (N = 99), of whom 61 (62 %) completed follow-up assessments at 16 weeks. Univariable logistic regression was conducted to determine the effects of intervention arm, method of recruitment, and participant characteristics (sociodemographic factors, and lifestyle, behavioural and attitudinal characteristics) on attrition, followed by multivariable logistic regression on those factors found to be related to attrition. Participants with low confidence to quit, and who were undertaking less than 150 mins of moderate and vigorous physical activity per week at baseline were less likely to complete the 16-week follow-up assessment. Exploratory analysis revealed that those who were lost to follow-up early in the trial (i.e., by 4 weeks), compared with those completing the study, were younger, had smoked for fewer years and had lower confidence to quit in the next 6 months. Participants who recorded a higher expired air carbon monoxide reading at baseline were more likely to drop out late in the study, as were those recruited via follow-up telephone calls. Multivariable analyses showed that only completing less than 150 mins of physical activity retained any confidence in predicting attrition in the presence of other variables. The findings indicate that those who take more effort to be recruited, are younger, are heavier smokers, have less confidence to quit, and are less physically active are more likely to withdraw or be lost to follow-up.

  17. Waiting Time Increases Risk of Attrition in Gambling Disorder Treatment

    DEFF Research Database (Denmark)

    Linnet, Jakob; Pedersen, Anders Sune

    2014-01-01

    Attrition is a well known problem in psychotherapeutic treatment. Patients with addiction have high attrition rates, and it is therefore important to identify factors that can improve completion rates in addiction. Here, we investigated the influence of waiting time as a predictor of treatment...

  18. Risk Attitudes, Sample Selection and Attrition in a Longitudinal Field Experiment

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Lau, Morten Igel

    with respect to risk attitudes. Our design builds in explicit randomization on the incentives for participation. We show that there are significant sample selection effects on inferences about the extent of risk aversion, but that the effects of subsequent sample attrition are minimal. Ignoring sample...... selection leads to inferences that subjects in the population are more risk averse than they actually are. Correcting for sample selection and attrition affects utility curvature, but does not affect inferences about probability weighting. Properly accounting for sample selection and attrition effects leads...... to findings of temporal stability in overall risk aversion. However, that stability is around different levels of risk aversion than one might naively infer without the controls for sample selection and attrition we are able to implement. This evidence of “randomization bias” from sample selection...

  19. Attrition, burnout, job dissatisfaction and occupational therapy managers.

    Science.gov (United States)

    Kraeger, M M; Walker, K F

    1992-01-01

    At a time when there is growing concern about the person-power shortages in occupational therapy, there is a need to address reasons why therapists leave the job market. Two job-related reasons for attrition are burnout and job dissatisfaction. The burnout phenomenon occurs as a result of personnel shortages, high-stress demands on therapists, the severity and complexity of client's problems, and the therapist's own ''worker personality.'' Bureaucratic constraints, limited advancement, issues related to a profession which is made up predominantly of women, lack of autonomy, and type of management and supervision are factors that contribute to job dissatisfaction. Occupational therapy managers can consider the causes of burnout and job dissatisfaction and initiate resources to retain therapists. Managers can increase the job benefits, such as flexible working hours, take steps to reduce stress in the workplace, offer career laddering opportunities, and promote staff development. By identifying the causes for attrition and by addressing those causes, the threat of losing therapists from the work force may be averted. Respondents (n = 106) to a survey of occupational therapy managers indicated that job dissatisfaction, burnout, and attrition of registered occupational therapists were not major problems in their settings. They reported a variety of strategies to reduce job dissatisfaction, burnout, and attrition. When these problems were present, managers cited bureaucratic red tape, lack of opportunity for advancement, and increasing role demands as contributing factors.

  20. Patterns of online student enrolment and attrition in Australian open access online education: a preliminary case study

    Directory of Open Access Journals (Sweden)

    Steven J Greenland

    2014-02-01

    Full Text Available Swinburne University of Technology has experienced tremendous growth in open access online learning and as such is typical of the many Australian institutions that have ventured into online tertiary education. While research in online education continues to expand, comparatively little investigates students’ enrolment and attrition.This research examines commencing enrolment and associated student withdrawal data, as well as performance scores from eight units forming a Marketing Major for an open access online undergraduate degree. Since data were collected over a five year period, trends and patterns within a substantial online undergraduate program can be explored.The paper discusses the challenges of analysing enrolment data. Initial findings suggest that retention strategies should be designed according to the stage students are at in their studies. Furthermore, the research informs the prioritisation and development of more effective enrolment and performance datareporting capabilities, which in turn would benefit student management and retention.http://dx.doi.org/10.5944/openpraxis.6.1.95

  1. Ash production by attrition in volcanic conduits and plumes.

    Science.gov (United States)

    Jones, T J; Russell, J K

    2017-07-17

    Tephra deposits result from explosive volcanic eruption and serve as indirect probes into fragmentation processes operating in subsurface volcanic conduits. Primary magmatic fragmentation creates a population of pyroclasts through volatile-driven decompression during conduit ascent. In this study, we explore the role that secondary fragmentation, specifically attrition, has in transforming primary pyroclasts upon transport in volcanic conduits and plumes. We utilize total grain size distributions from a suite of natural and experimentally produced tephra to show that attrition is likely to occur in all explosive volcanic eruptions. Our experimental results indicate that fine ash production and surface area generation is fast (eruption column stability, tephra dispersal, aggregation, volcanic lightening generation, and has concomitant effects on aviation safety and Earth's climate.

  2. Elements related to attrition of women faculty at the University of Pittsburgh, School of Medicine: A case study

    Science.gov (United States)

    Gandhi, Pooja

    Recent studies have shown that the number of women faculty in academic medicine is much lesser than the number of women that are graduating from medical schools. Many academic institutes face the challenge of retaining talented faculty and this attrition from academic medicine prevents career advancement of women faculty. This case study attempts to identify some of the reasons for dissatisfaction that may be related to the attrition of women medical faculty at the University of Pittsburgh, School of Medicine. Data was collected using a job satisfaction survey, which consisted of various constructs that are part of a faculty's job and proxy measures to gather the faculty's intent to leave their current position at the University of Pittsburgh or academic medicine in general. The survey results showed that although women faculty were satisfied with their job at the University of Pittsburgh, there are some important factors that influenced their decision of potentially dropping out. The main reasons cited by the women faculty were related to funding pressures, work-life balance, mentoring of junior faculty and the amount of time spent on clinical responsibilities. The analysis of proxy measures showed that if women faculty decided to leave University of Pittsburgh, it would most probably be due to better opportunity elsewhere followed by pressure to get funding. The results of this study aim to provide the School of Medicine at the University of Pittsburgh with information related to attrition of its women faculty and provide suggestions for implications for policy to retain their women faculty.

  3. Factors affecting employee attrition among engineers and non-engineers in manufacturing industry

    Directory of Open Access Journals (Sweden)

    Bhardwaj, Shikha

    2017-12-01

    Full Text Available Almost every industry nowadays is badly affected by attrition. Retention of talented employees is the biggest problem faced by India Incorporation. In order to gather more insights on the talent crunch, the undertaken study was conducted on technical and non-technical jobs in manufacturing sector in Delhi NCR. Research has identified three major factors – Salary, Boss and Stress in the jobs after conducted interviews with around 50 technical and non-technical respondents. A set of questions were prepared and send to 120 employee but only 75 responded. The study shows a strong relationship between type of job and factors of attrition. Chi-square test clearly states strong relationship among two. Thus, any change in one will affect the other also. At the same time other important outcomes were that for technical jobs salary is the most important factor whereas non-technical Boss is the factor. Out 75, 63 were engineer and rest were non-engineer. The research can be further done to understand factors of attrition with other demographic variable.

  4. The Role of Personality Type on Minority Attrition at the US Naval Academy

    Science.gov (United States)

    2002-06-01

    Provost as more likely to attrite were ISTP, ESTP, ISFP, and ENFJ . “These students tend to be less organized, more passive in their relationship to...MBTI ISTP ISTJ ISFP ISFJ INTP INTJ INFP INFJ ESTP ESTJ ESFP ESFJ ENTP ENTJ ENFP ENFJ C ou nt 400 300 200 100 0 33 Table 12: Minority Attrition...reason to believe that all who are admitted have the potential to graduate. B. PURPOSE OF STUDY This thesis examines the relationship

  5. Personal, Situational, and Organizational Determinants of Navy Enlisted Attrition

    Science.gov (United States)

    1980-06-01

    of regular high school instruction. The GED test battery contains five testsz writing skills, social studies, science, reading skills, and mathematics ...expanded apprentice train- ing program for airmen and seamen might, ceteris paribus, bring the GENDET attrition rate closer to acceptable lvels . 13 ] KN

  6. The Canadian Forces Recruitment/Attrition Model

    National Research Council Canada - National Science Library

    Wait, Tracey

    1998-01-01

    ...), as part of its mandate to provide analysis of potential impacts of trends and change on defense and defense related issues, has designed a prototype model of recruitment and attrition of the Canadian Forces (C F...

  7. Association between recruitment methods and attrition in Internet-based studies.

    Directory of Open Access Journals (Sweden)

    Paolo Bajardi

    Full Text Available Internet-based systems for epidemiological studies have advantages over traditional approaches as they can potentially recruit and monitor a wider range of individuals in a relatively inexpensive fashion. We studied the association between communication strategies used for recruitment (offline, online, face-to-face and follow-up participation in nine Internet-based cohorts: the Influenzanet network of platforms for influenza surveillance which includes seven cohorts in seven different European countries, the Italian birth cohort Ninfea and the New Zealand birth cohort ELF. Follow-up participation varied from 43% to 89% depending on the cohort. Although there were heterogeneities among studies, participants who became aware of the study through an online communication campaign compared with those through traditional offline media seemed to have a lower follow-up participation in 8 out of 9 cohorts. There were no clear differences in participation between participants enrolled face-to-face and those enrolled through other offline strategies. An Internet-based campaign for Internet-based epidemiological studies seems to be less effective than an offline one in enrolling volunteers who keep participating in follow-up questionnaires. This suggests that even for Internet-based epidemiological studies an offline enrollment campaign would be helpful in order to achieve a higher participation proportion and limit the cohort attrition.

  8. Effect of acidity upon attrition-corrosion of human dental enamel.

    Science.gov (United States)

    Wu, Yun-Qi; Arsecularatne, Joseph A; Hoffman, Mark

    2015-04-01

    Attrition-corrosion is a synthesized human enamel wear process combined mechanical effects (attrition) with corrosion. With the rising consumption of acidic food and beverages, attrition-corrosion is becoming increasingly common. Yet, research is limited and the underlying mechanism remains unclear. In this study, in vitro wear loss of human enamel was investigated and the attrition-corrosion process and wear mechanism were elucidated by the analysis of the wear scar and its subsurface using focused ion beam (FIB) sectioning and scanning electron microscopy (SEM). Human enamel flat-surface samples were prepared with enamel cusps as the wear antagonists. Reciprocating wear testing was undertaken under load of 5N at the speed of 66 cycle/min for 2250 cycles with lubricants including citric acid (at pH 3.2 and 5.5), acetic acid (at pH 3.2 and 5.5) and distilled water. All lubricants were used at 37°C. Similar human enamel flat-surface samples were also exposed to the same solutions as a control group. The substance loss of enamel during wear can be linked to the corrosion potential of a lubricant used. Using a lubricant with very low corrosion potential (such as distilled water), the wear mechanism was dominated by delamination with high wear loss. Conversely, the wear mechanism changed to shaving of the softened layer with less material loss in an environment with medium corrosion potential such as citric acid at pH 3.2 and 5.5 and acetic acid at pH 5.5. However, a highly corrosive environment (e.g., acetic acid at pH 3.2) caused the greatest loss of substance during wear. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Attitudes towards attrition among UK trainees in obstetrics and gynaecology

    OpenAIRE

    Gafson, I.; Currie, J.; O Dwyer, S.; Woolf, K.; Griffin, A.

    2017-01-01

    Physician dissatisfaction in the workplace has consequences for patient safety. Currently in the UK, 1 in 5 doctors who enter specialist training in obstetrics and gynaecology leave the programme before completion. Trainee attrition has implications for workforce planning, organization of health-care services and patient care. The authors conducted a survey of current trainees' and former trainees' views concerning attrition and ‘peri-attrition’ – a term coined to describe the trainee who has...

  10. Attrition resistant gamma-alumina catalyst support

    Science.gov (United States)

    Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

    2006-03-14

    A .gamma.-alumina catalyst support having improved attrition resistance produced by a method comprising the steps of treating a particulate .gamma.-alumina material with an acidic aqueous solution comprising water and nitric acid and then, prior to adding any catalytic material thereto, calcining the treated .gamma.-alumina.

  11. Predictors of Short- and Long-Term Attrition From the Parents as Agents of Change Randomized Controlled Trial for Managing Pediatric Obesity.

    Science.gov (United States)

    Spence, Nicholas D; Newton, Amanda S; Keaschuk, Rachel A; Ambler, Kathryn A; Jetha, Mary M; Holt, Nicholas L; Rosychuk, Rhonda J; Spence, John C; Sharma, Arya M; Ball, Geoff D C

    Attrition in pediatric weight management is a substantial problem. This study examined factors associated with short- and long-term attrition from a lifestyle and behavioral intervention for parents of children with overweight or obesity. Fifty-two families with children ages 6 to 12 years old and body mass index at or above the 85th percentile participated in a randomized controlled trial focused on parents, comparing parent-based cognitive behavioral therapy with parent-based psychoeducation for pediatric weight management. We examined program attrition using two clinical phases of the intervention: short-term and long-term attrition, modeled using the general linear model. Predictors included intervention type, child/parent weight status, sociodemographic factors, and health of the family system. Higher self-assessed health of the family system was associated with lower short-term attrition; higher percentage of intervention sessions attended by parents was associated with lower long-term attrition. Different variables were significant in our short- and long-term models. Attrition might best be conceptualized based on short- and long-term phases of clinical, parent-based interventions for pediatric weight management. Copyright © 2016 National Association of Pediatric Nurse Practitioners. Published by Elsevier Inc. All rights reserved.

  12. Navy Recruit Attrition Prediction Modeling

    Science.gov (United States)

    2014-09-01

    have high correlation with attrition, such as age, job characteristics, command climate, marital status, behavior issues prior to recruitment, and the...the additive model. glm(formula = Outcome ~ Age + Gender + Marital + AFQTCat + Pay + Ed + Dep, family = binomial, data = ltraining) Deviance ...0.1 ‘ ‘ 1 (Dispersion parameter for binomial family taken to be 1) Null deviance : 105441 on 85221 degrees of freedom Residual deviance

  13. A Conceptual Framework for Evaluating Attrition in Online Courses

    Science.gov (United States)

    Laing, C. Linda; Laing, Gregory K.

    2015-01-01

    The purpose of this paper is to develop a conceptual framework that considers the role that the sense of isolation and alienation play in contributing to attrition in online courses in the higher education sector. The approach adopted in this paper is a theoretical study aimed at synthesizing existing theories. The ultimate contribution of this…

  14. Examining the Relationship Between Mental, Physical, and Organizational Factors Associated With Attrition During Maritime Forces Training.

    Science.gov (United States)

    Binsch, Olaf; Banko, Katherine M; Veenstra, Bertil J; Valk, Pierre J L

    2015-11-01

    For infantry units of the Dutch Ministry of Defence, high attrition rates (varying from 42 to 68%) during initial training are a persisting problem. The reasons for this attrition are diverse. Having better insight into the causes of attrition is a prerequisite for implementing preventive measures. To achieve this, a monitoring assessment system was developed that integrated the effects of physical, mental, and organizational determinants on operational readiness. The aim of this study was to implement the monitoring tools and to establish the set of determinants that best predicted attrition during infantry training of new recruits. Eighty-five recruits were monitored over a 24-week infantry training course. Before the training, recruits were screened for medical, psychological, and physical wellness. During the monitoring phase, mental, physiological, and organizational indicants were obtained using an array of tools such as questionnaires, chest belt monitors (for heart rate, acceleration, and skin temperature measurements), and computerized tests (e.g., vigilance, long-term memory). Survival analyses were used to tease out the determinants of individual and grouped predictors of attrition. Nearly half the recruits (47%) failed the training. Attrition was predicted by both physiological and mental determinants. However, the organizational determinant "trainers' judgment" on the "recruits' military quality" dominated the physiological and mental determinants. It was concluded that the monitoring system was successfully implemented during infantry training, and that the survival analysis method emphasized on single effects and interactions between the different determinants. Based on the current findings, we recommend several steps to successfully implement a monitoring method in settings with high demands.

  15. Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

    Energy Technology Data Exchange (ETDEWEB)

    Adeyiga, Adeyinka

    2010-02-05

    Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditions as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).

  16. Attrition from Student Affairs: Perspectives from Those Who Exited the Profession

    Science.gov (United States)

    Marshall, Sarah M.; Gardner, Megan Moore; Hughes, Carole; Lowery, Ute

    2016-01-01

    Attrition of student affairs professionals is an issue of concern for the profession. This mixed methods study highlights reasons why participants left their student affairs careers. Seven general themes emerged from the study, including burnout, salary issues, career alternatives, work/family conflict, limited advancement, supervisor issues and…

  17. First Language Attrition Induces Changes in Online Morphosyntactic Processing and Re-Analysis: An ERP Study of Number Agreement in Complex Italian Sentences

    Science.gov (United States)

    Kasparian, Kristina; Vespignani, Francesco; Steinhauer, Karsten

    2017-01-01

    First language (L1) attrition in adulthood offers new insight on neuroplasticity and the role of language experience in shaping neurocognitive responses to language. Attriters are multilinguals for whom advancing L2 proficiency comes at the cost of the L1, as they experience a shift in exposure and dominance (e.g., due to immigration). To date,…

  18. Comparison of trial participants and open access users of a web-based physical activity intervention regarding adherence, attrition, and repeated participation.

    Science.gov (United States)

    Wanner, Miriam; Martin-Diener, Eva; Bauer, Georg; Braun-Fahrländer, Charlotte; Martin, Brian W

    2010-02-10

    Web-based interventions are popular for promoting healthy lifestyles such as physical activity. However, little is known about user characteristics, adherence, attrition, and predictors of repeated participation on open access physical activity websites. The focus of this study was Active-online, a Web-based individually tailored physical activity intervention. The aims were (1) to assess and compare user characteristics and adherence to the website (a) in the open access context over time from 2003 to 2009, and (b) between trial participants and open access users; and (2) to analyze attrition and predictors of repeated use among participants in a randomized controlled trial compared with registered open access users. Data routinely recorded in the Active-online user database were used. Adherence was defined as: the number of pages viewed, the proportion of visits during which a tailored module was begun, the proportion of visits during which tailored feedback was received, and the time spent in the tailored modules. Adherence was analyzed according to six one-year periods (2003-2009) and according to the context (trial or open access) based on first visits and longest visits. Attrition and predictors of repeated participation were compared between trial participants and open access users. The number of recorded visits per year on Active-online decreased from 42,626 in 2003-2004 to 8343 in 2008-2009 (each of six one-year time periods ran from April 23 to April 22 of the following year). The mean age of users was between 38.4 and 43.1 years in all time periods and both contexts. The proportion of women increased from 49.5% in 2003-2004 to 61.3% in 2008-2009 (Popen access users. For open access users, adherence was similar during the first and the longest visits; for trial participants, adherence was lower during the first visits and higher during the longest visits. Of registered open access users and trial participants, 25.8% and 67.3% respectively visited Active

  19. Lead optimization attrition analysis (LOAA): a novel and general methodology for medicinal chemistry.

    Science.gov (United States)

    Munson, Mark; Lieberman, Harvey; Tserlin, Elina; Rocnik, Jennifer; Ge, Jie; Fitzgerald, Maria; Patel, Vinod; Garcia-Echeverria, Carlos

    2015-08-01

    Herein, we report a novel and general method, lead optimization attrition analysis (LOAA), to benchmark two distinct small-molecule lead series using a relatively unbiased, simple technique and commercially available software. We illustrate this approach with data collected during lead optimization of two independent oncology programs as a case study. Easily generated graphics and attrition curves enabled us to calibrate progress and support go/no go decisions on each program. We believe that this data-driven technique could be used broadly by medicinal chemists and management to guide strategic decisions during drug discovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. A Longitudinal Examination of First Term Attrition and Reenlistment among FY1999 Enlisted Accessions

    National Research Council Canada - National Science Library

    Strickland, William J

    2005-01-01

    ... the service, completed training segments, conducted duty assignments, and left the service. These models explored reasons for attrition and reenlistment intentions, and suggested management strategies that might be employed to reduce attrition...

  1. Vocation, friendship and resilience: a study exploring nursing student and staff views on retention and attrition.

    Science.gov (United States)

    Williamson, Graham R; Health, Val; Proctor-Childs, Tracey

    2013-01-01

    There is international concern about retention of student nurses on undergraduate programmes. United Kingdom Higher Education Institutions are monitored on their attrition statistics and can be penalised financially, so they have an incentive to help students remain on their programmes beyond their moral duty to ensure students receive the best possible educational experience. to understand students' and staff concerns about programmes and placements as part of developing our retention strategies. This study reports qualitative data on retention and attrition collected as part of an action research study. One University School of Nursing and Midwifery in the South West of England. Staff, current third year and ex-student nurses from the adult field. Data were collected in focus groups, both face-to face and virtual, and individual telephone interviews. These were transcribed and subjected to qualitative content analysis. FOUR THEMES EMERGED: Academic support, Placements and mentors, Stresses and the reality of nursing life, and Dreams for a better programme. The themes Academic support, Placements and mentors and Stresses and the reality of nursing life, resonate with international literature. Dreams for a better programme included smaller group learning. Vocation, friendship and resilience seem instrumental in retaining students, and Higher Education Institutions should work to facilitate these. 'Vocation' has been overlooked in the retention discussions, and working more actively to foster vocation and belongingness could be important.

  2. Identification of cognitive and non-cognitive predictive variables related to attrition in baccalaureate nursing education programs in Mississippi

    Science.gov (United States)

    Hayes, Catherine

    2005-07-01

    This study sought to identify a variable or variables predictive of attrition among baccalaureate nursing students. The study was quantitative in design and multivariate correlational statistics and discriminant statistical analysis were used to identify a model for prediction of attrition. The analysis then weighted variables according to their predictive value to determine the most parsimonious model with the greatest predictive value. Three public university nursing education programs in Mississippi offering a Bachelors Degree in Nursing were selected for the study. The population consisted of students accepted and enrolled in these three programs for the years 2001 and 2002 and graduating in the years 2003 and 2004 (N = 195). The categorical dependent variable was attrition (includes academic failure or withdrawal) from the program of nursing education. The ten independent variables selected for the study and considered to have possible predictive value were: Grade Point Average for Pre-requisite Course Work; ACT Composite Score, ACT Reading Subscore, and ACT Mathematics Subscore; Letter Grades in the Courses: Anatomy & Physiology and Lab I, Algebra I, English I (101), Chemistry & Lab I, and Microbiology & Lab I; and Number of Institutions Attended (Universities, Colleges, Junior Colleges or Community Colleges). Descriptive analysis was performed and the means of each of the ten independent variables was compared for students who attrited and those who were retained in the population. The discriminant statistical analysis performed created a matrix using the ten variable model that was able to correctly predicted attrition in the study's population in 77.6% of the cases. Variables were then combined and recombined to produce the most efficient and parsimonious model for prediction. A six variable model resulted which weighted each variable according to predictive value: GPA for Prerequisite Coursework, ACT Composite, English I, Chemistry & Lab I, Microbiology

  3. Screening for depression and anxiety : Correlates of non-response and cohort attrition in the Netherlands Study of Depression and Anxiety (NESDA)

    NARCIS (Netherlands)

    Van Der Veen, Willem Jan; Van Der Meer, Klaas; Penninx, Brenda W.

    2009-01-01

    A major problem in the analysis of attrition of cohorts in Studies on mental health problems is that data on those who do not participate at the outset of a study are largely unavailable. It is not known how underlying psychopathology affects the first stages of screening where non-response and

  4. A systematic review of satisfaction and pediatric obesity treatment: new avenues for addressing attrition.

    Science.gov (United States)

    Skelton, Joseph A; Irby, Megan Bennett; Geiger, Ann M

    2014-01-01

    Pediatric obesity treatment programs report high attrition rates, but it is unknown if family experience and satisfaction contributes. This review surveys the literature regarding satisfaction in pediatric obesity and questions used in measurement. A systematic review of the literature was conducted using Medline, PsychINFO, and CINAHL. Studies of satisfaction in pediatric weight management were reviewed, and related studies of obesity were included. Satisfaction survey questions were obtained from the articles or from the authors. Eighteen studies were included; 14 quantitative and 4 qualitative. Only one study linked satisfaction to attrition, and none investigated the association of satisfaction and weight outcomes. Most investigations included satisfaction as a secondary aim or used single-item questions of overall satisfaction; only one assessed satisfaction in noncompleters. Overall, participants expressed high levels of satisfaction with obesity treatment or prevention programs. Surveys focused predominantly on overall satisfaction or specific components of the program. Few in-depth studies of satisfaction with pediatric obesity treatment have been conducted. Increased focus on family satisfaction with obesity treatment may provide an avenue to lower attrition rates and improve outcomes. Enhancing measurement of satisfaction to yield actionable responses could positively influence outcomes, and a framework, via patient-centered care principles, is provided. © 2013 National Association for Healthcare Quality.

  5. Predictors of attrition with buprenorphine/naloxone treatment in opioid dependent youth☆

    Science.gov (United States)

    Warden, Diane; Subramaniam, Geetha A.; Carmody, Thomas; Woody, George E.; Minhajuddin, Abu; Poole, Sabrina A.; Potter, Jennifer; Fishman, Marc; Bogenschutz, Michael; Patkar, Ashwin; Trivedi, Madhukar H.

    2012-01-01

    Background In opioid dependent youth there is substantial attrition from medication-assisted treatment. If youth at risk for attrition can be identified at treatment entry or early in treatment, they can be targeted for interventions to help retain them in treatment. Methods Opioid dependent adolescents and young adults (n=152), aged 15–21, were randomized to 12 weeks (BUP, n=74) or 2 weeks of detoxification (DETOX, n=78) with buprenorphine/naloxone (Bup/Nal), both in combination with 12 weeks of psychosocial treatment. Baseline and early treatment related predictors of treatment attrition were identified in each group using bivariate and multivariate logistic regression. Results In the DETOX group 36% left between weeks 2 and 4, at the end of the dose taper, while in the BUP group only 8% left by week 4. In the BUP group, early adherence to Bup/Nal, early opioid negative urines, use of any medications in the month prior to treatment entry, and lifetime non-heroin opioid use were associated with retention while prior 30-day hallucinogen use was associated with attrition. In the DETOX group, only use of sleep medications was associated with retention although not an independent predictor. A broad range of other pre-treatment characteristics was unrelated to attrition. Conclusions Prompt attention to those with early non-adherence to medication or an early opioid positive urine, markers available in the first 2 weeks of treatment, may improve treatment retention. Extended Bup/ Nal treatment appeared effective in improving treatment retention for youth with opioid dependence across a wide range of demographics, and pre-treatment clinical characteristics. PMID:22626890

  6. Predictors of attrition with buprenorphine/naloxone treatment in opioid dependent youth.

    Science.gov (United States)

    Warden, Diane; Subramaniam, Geetha A; Carmody, Thomas; Woody, George E; Minhajuddin, Abu; Poole, Sabrina A; Potter, Jennifer; Fishman, Marc; Bogenschutz, Michael; Patkar, Ashwin; Trivedi, Madhukar H

    2012-09-01

    In opioid dependent youth there is substantial attrition from medication-assisted treatment. If youth at risk for attrition can be identified at treatment entry or early in treatment, they can be targeted for interventions to help retain them in treatment. Opioid dependent adolescents and young adults (n=152), aged 15-21, were randomized to 12 weeks (BUP, n=74) or 2 weeks of detoxification (DETOX, n=78) with buprenorphine/naloxone (Bup/Nal), both in combination with 12 weeks of psychosocial treatment. Baseline and early treatment related predictors of treatment attrition were identified in each group using bivariate and multivariate logistic regression. In the DETOX group 36% left between weeks 2 and 4, at the end of the dose taper, while in the BUP group only 8% left by week 4. In the BUP group, early adherence to Bup/Nal, early opioid negative urines, use of any medications in the month prior to treatment entry, and lifetime non-heroin opioid use were associated with retention while prior 30-day hallucinogen use was associated with attrition. In the DETOX group, only use of sleep medications was associated with retention although not an independent predictor. A broad range of other pre-treatment characteristics was unrelated to attrition. Prompt attention to those with early non-adherence to medication or an early opioid positive urine, markers available in the first 2 weeks of treatment, may improve treatment retention. Extended Bup/Nal treatment appeared effective in improving treatment retention for youth with opioid dependence across a wide range of demographics, and pre-treatment clinical characteristics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Attrition of limestone by impact loading in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Fabrizio Scala; Fabio Montagnaro; Piero Salatino [Consiglio Nazionale delle Ricerche, Napoli (Italy). Istituto di Ricerche sulla Combustione

    2007-09-15

    The present study addresses limestone attrition and fragmentation associated with impact loading, a process which may occur extensively in various regions of fluidized bed (FB) combustors/gasifiers, primarily the jetting region of the bottom bed, the exit region of the riser, and the cyclone. An experimental protocol for the characterization of the propensity of limestone to undergo attrition/fragmentation by impact loading is reported. The application of the protocol is demonstrated with reference to an Italian limestone whose primary fragmentation and attrition by surface wear have already been characterized in previous studies. The experimental procedure is based on the characterization of the amount and particle size distribution of the debris generated upon the impact of samples of sorbent particles against a target. Experiments were carried out at a range of particle impact velocities between 10 and 45 m/s, consistent with jet velocities corresponding to typical pressure drops across FB gas distributors. The protocol has been applied to either raw or preprocessed limestone samples. In particular, the effect of calcination, sulfation, and calcination/recarbonation cycles on the impact damage suffered by sorbent particles has been assessed. The measurement of particle voidage and pore size distribution by mercury intrusion was also accomplished to correlate fragmentation with the structural properties of the sorbent samples. Fragmentation by impact loading of the limestone is significant. Lime displays the largest propensity to undergo impact damage, followed by the sorbent sulfated to exhaustion, the recarbonated sorbent, and the raw limestone. Fragmentation of the raw limestone and of the sulfated lime follows a pattern typical of the failure of brittle materials. The fragmentation behavior of lime and recarbonated lime better conforms to a disintegration failure mode, with an extensive generation of very fine fragments. 27 refs., 9 figs. 1 tab.

  8. Could Realistic Job Previews Reduce First-Term Attrition

    National Research Council Canada - National Science Library

    Brose, Gary

    1999-01-01

    .... The military's use of educational screens, trends and costs of first-term attrition, and labor market theories of turnover are discussed to provide a common frame of reference within which to view...

  9. Explaining attrition and decreased effectiveness of experienced teachers: A research synthesis.

    Science.gov (United States)

    Torenbeek, Marjolein; Peters, Velibor

    2017-01-01

    Teacher retention and development of the full potential of teachers is important at a national level in order to be able to belong to the top world economies. A number of studies suggests that part of the group of experienced teachers with more than 20 years of experience perform didactically at a lower level than would be expected and are at a greater risk for attrition. The aim of the present study is to find explanations for this by making use of the Job Demands Resources Model. Specific demands of the teaching profession, interpersonal demands related to the developmental stage of experienced teachers, job resources and personal resources in relation to health and motivation are explored by reviewing a vast amount of literature. The proposed conceptual model is an extension of the Job Demands Resources Model with the inclusion of personal demands related to adulthood and personal resources. The resulting model provides us with clues on how attrition and decreased performance could be counteracted.

  10. Predicting Student Attrition with Data Mining Methods

    Science.gov (United States)

    Delen, Dursun

    2012-01-01

    Affecting university rankings, school reputation, and financial well-being, student retention has become one of the most important measures of success for higher education institutions. From the institutional perspective, improving student retention starts with a thorough understanding of the causes behind the attrition. Such an understanding is…

  11. Implications of Attrition in a Longitudinal Web-Based Survey: An Examination of College Students Participating in a Tobacco Use Study.

    Science.gov (United States)

    McDonald, Bennett; Haardoerfer, Regine; Windle, Michael; Goodman, Michael; Berg, Carla

    2017-10-16

    Web-based survey research has several benefits, including low cost and burden, as well as high use of the Internet, particularly among young adults. In the context of longitudinal studies, attrition raises concerns regarding the validity of data, given the potential associations with individual and institutional characteristics, or the focal area of study (eg, cigarette use). The objective of this study was to compare baseline characteristics of nonresponders versus responders in a sample of young adult college students in a Web-based longitudinal study regarding tobacco use. We conducted a secondary data analysis of 3189 college students from seven Georgia colleges and universities in a 2-year longitudinal study. We examined baseline tobacco use, as well as individual- and institutional-level factors, as predictors of attrition between wave 1 (October and November 2014) and wave 2 (February and March 2015) using multilevel modeling. Results: A total 13.14% (419/3189) participants were lost to follow-up at wave 2. Predictors of nonresponse were similar in the models examining individual-level factors and institutional-level factors only and included being black versus white (odds ratio [OR] 1.74, CI 1.23-2.46); being male versus female (OR 1.41, CI 1.10-1.79); seeking a bachelor's degree versus advanced degree (OR 1.41, CI 1.09-1.83); not residing on campus (OR 0.62, CI 0.46-0.84); past 30-day tobacco use (OR 1.41, CI 1.10-1.78); attending a nonprivate college (OR 0.48, CI 0.33-0.71); and attending a college with ≤10,000 students (OR 0.56, CI 0.43-0.73). Future longitudinal studies should assess predictors of attrition to examine how survey topic and other individual and institutional factors might influence the response to allow for correction of selection bias. ©Bennett McDonald, Regine Haardoerfer, Michael Windle, Michael Goodman, Carla Berg. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 16.10.2017.

  12. Patterns of Student Enrolment and Attrition in Australian Open Access Online Education: A Preliminary Case Study

    Science.gov (United States)

    Greenland, Steven J.; Moore, Catherine

    2014-01-01

    Swinburne University of Technology has experienced tremendous growth in open access online learning and as such is typical of the many Australian institutions that have ventured into online tertiary education. While research in online education continues to expand, comparatively little investigates students' enrolment and attrition. This research…

  13. Attrition in longitudinal randomized controlled trials: home visits make a difference

    Directory of Open Access Journals (Sweden)

    Peterson Janey C

    2012-11-01

    Full Text Available Abstract Background Participant attrition in longitudinal studies can introduce systematic bias, favoring participants who return for follow-up, and increase the likelihood that those with complications will be underestimated. Our aim was to examine the effectiveness of home follow-up (Home F/U to complete the final study evaluation on potentially “lost” participants by: 1 evaluating the impact of including and excluding potentially “lost” participants (e.g., those who required Home F/U to complete the final evaluation on the rates of study complications; 2 examining the relationship between timing and number of complications on the requirement for subsequent Home F/U; and 3 determining predictors of those who required Home F/U. Methods We used data from a randomized controlled trial (RCT conducted from 1991–1994 among coronary artery bypass graft surgery patients that investigated the effect of High mean arterial pressure (MAP (intervention vs. Low MAP (control during cardiopulmonary bypass on 5 complications: cardiac morbidity/mortality, neurologic morbidity/mortality, all-cause mortality, neurocognitive dysfunction and functional decline. We enhanced completion of the final 6-month evaluation using Home F/U. Results Among 248 participants, 61 (25% required Home F/U and the remaining 187 (75% received Routine F/U. By employing Home F/U, we detected 11 additional complications at 6 months: 1 major neurologic complication, 6 cases of neurocognitive dysfunction and 4 cases of functional decline. Follow-up of 61 additional Home F/U participants enabled us to reach statistical significance on our main trial outcome. Specifically, the High MAP group had a significantly lower rate of the Combined Trial Outcome compared to the Low MAP group, 16.1% vs. 27.4% (p=0.032. In multivariate analysis, participants who were ≥ 75 years (OR=3.23, 95% CI 1.52-6.88, p=0.002 or on baseline diuretic therapy (OR=2.44, 95% CI 1.14-5.21, p=0.02 were more

  14. Factors of Attrition in Cohort Doctoral Education: A Self-Determination Theory Perspective

    Science.gov (United States)

    Garcia, Linda Ann

    2013-01-01

    Attrition rates, completion rates, and time to degree are the key areas researchers have sought to examine influencing factors and patterns of behavior that describe the departure process of students in doctoral study. Through the lens of self-determination theory (Deci & Ryan, 1985), the purpose of this phenomenological qualitative study was…

  15. Determination of the attrition resistance of granular charcoals

    International Nuclear Information System (INIS)

    Dietz, V.R.

    1979-01-01

    A laboratory procedure has been developed to evaluate the attrition of granular adsorbent charcoals on passing an air flow through the bed. Two factors observed in plant operations were selected as relevant: (1) the characteristic structural vibrations in plant scale equipment (motors, fans, etc.) that are transmitted to charcoal particles and cause the particles to move and rub each other, and (2) the rapid air flow that results in the movement of the attrited dust. In the test a container for charcoal [50 mm diameter and 50 mm high] was vibrated at a frequency of 60 Hz and at a constant energy input manually controlled using a vibration meter in the acceleration mode. Simultaneously, air was applied and exited through glass fiber filter paper. The quantity of dust trapped on the exit filter was then determined, either optically or gravimetrically. The dust formed per minute (attrition coefficient) was found to approach a constant value. The plateau-values from sequential determinations varied with the source of the charcoal; a 5-fold difference was found among a large variety of commercial products. The first testing of a sample released the excess dust accumulated in previous handling of the charcoal. The plateau values were then attained in the succeeding tests and these were characteristic of the material. The results were compared with those obtained for the same charcoals using older test methods such as the Ball and Pan Hardness Test described in RDTM16-1T

  16. Early nurse attrition in New Zealand and associated policy implications.

    Science.gov (United States)

    Walker, L; Clendon, J

    2018-03-01

    To examine the factors contributing to nurses choosing to exit the nursing profession before retirement age. Population growth, ageing and growing demand for health services mean increased demand for nurses. Better retention could help meet this demand, yet little work has been done in New Zealand to understand early attrition. An online survey of registered and enrolled nurses and nurse practitioners who had left nursing was used. This study reports analysis of responses from 285 ex-nurses aged under 55. The primary reasons nurses left the profession were as follows: workplace concerns; personal challenges; career factors; family reasons; lack of confidence; leaving for overseas; unwillingness to complete educational requirements; poor work-life balance; and inability to find suitable nursing work. Most nurses discussed their intentions to leave with a family member or manager and most reported gaining transferrable skills through nursing. Nurses leave for many reasons. Implementing positive practice environments and individualized approaches to retaining staff may help reduce this attrition. Generational changes in the nature of work and careers mean that nurses may continue to leave the profession sooner than anticipated by policymakers. If the nursing workforce is to be able to meet projected need, education, recruitment and retention policies must urgently address issues leading to early attrition. In particular, policies improving the wider environmental context of nursing practice and ensuring that working environments are safe and nurses are well supported must be developed and implemented. Equally, national nursing workforce planning must take into account that nursing is no longer viewed as a career for life. © 2017 International Council of Nurses.

  17. Listen-Identify-Brainstorm-Reality-Test-Encourage (LIBRE) Problem-Solving Model: Addressing Special Education Teacher Attrition through a Cognitive-Behavioral Approach to Teacher Induction

    Science.gov (United States)

    Guerra, Norma S.; Hernandez, Art; Hector, Alison M.; Crosby, Shane

    2015-01-01

    Special education teacher attrition rates continue to challenge the profession. A cognitive-behavioral problem-solving approach was used to examine three alternative certification program special education teachers' professional development through a series of 41 interviews conducted over a 2-year period. Beginning when they were novice special…

  18. Flue gas desulfurization under simulated oxyfiring fluidized bed combustion conditions: The influence of limestone attrition and fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Scala, F.; Salatino, P. [CNR, Naples (Italy)

    2010-01-01

    Flue gas desulfurization by means of limestone injection under simulated fluidized bed oxyfiring conditions was investigated, with a particular focus on particle attrition and fragmentation phenomena. An experimental protocol was applied, based on the use of complementary techniques that had been previously developed for the characterization of attrition of sorbents in air-blown atmospheric fluidized bed combustors. The extent and pattern of limestone attrition by surface wear in the dense phase of a fluidized bed were assessed in bench scale fluidized bed experiments under simulated oxyfiring conditions. Sorbent samples generated during the oxyfiring tests were further characterized from the standpoint of fragmentation upon high velocity impact by means of a particle impactor. The experimental results were compared with those previously obtained with the same limestone under air-blown atmospheric fluidized bed combustion conditions. The profound differences in the attrition and fragmentation extents and patterns associated with oxyfiring as compared to air-blown atmospheric combustion and the role played by the different attrition/fragmentation paths were highlighted. In particular, it was noted that attrition could effectively enhance particle sulfation under oxyfiring conditions by continuously disclosing unconverted calcium to the sulfur-bearing atmosphere.

  19. From emigrant to expat : Changed perspectives on first language attrition in a digital era

    NARCIS (Netherlands)

    Keijzer, Merel

    2015-01-01

    L1 attrition is the (partial) language loss that is found in healthy individuals who stop routinely using their L1 after moving to an L2 environment. Over the years, the phenomenon has attracted much interest, from the general public who have (directly and indirectly) experienced attrition, but also

  20. Dreams and disappointments regarding nursing: Student nurses' reasons for attrition and retention. A qualitative study design.

    Science.gov (United States)

    Ten Hoeve, Yvonne; Castelein, Stynke; Jansen, Gerard; Roodbol, Petrie

    2017-07-01

    In the Netherlands, hundreds of students register annually for a nursing programme, but not all of these students manage to complete their training. The main aim of this study was to examine which factors affect student nurses' decision to leave or complete their programme. The study used an exploratory descriptive design, employing a qualitative phenomenological approach. Student nurses (n=17) at the beginning of their third year of the four-year Bachelor's programme. Data were collected at four Universities of Applied Sciences in the Netherlands, from December 2013 to January 2014. Semi-structured interviews were used to collect the data, using an interview guide. The main reasons for students to become nurses were the caring aspect, personal experiences with healthcare, role models in their immediate environment, and job opportunities. They had both altruistic and professional perceptions of their profession. Reasons for attrition were strongly related to the training programme and to their clinical placements, in particular the perceived lack of support from mentors and team. Feelings of being welcomed and working in a nice team proved to be more important reasons for completing the programme than the specific clinical field. Student nurses started their studies with many dreams, such as caring for people and having the opportunity to deliver excellent nursing care. When their expectations were not met, their dreams became disappointments which caused them to consider stopping and even to leave (attrition). The role of lecturers and mentors seems invaluable in protecting and guiding students through their programme and placements. Optimal cooperation between lecturers and mentors is of paramount importance to retain student nurses in their training programmes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of sample attrition in a longitudinal study of the association between alcohol intake and all-cause mortality

    DEFF Research Database (Denmark)

    Thygesen, Lau C; Johansen, Christoffer; Keiding, Niels

    2008-01-01

    of this study were to characterize participants who dropped out and to evaluate whether the missing information influenced the association between alcohol intake and all-cause mortality. Design and participants Data on the 18 974 participants in the Copenhagen City Heart Study, with four measures of alcohol...... intake and other life-style factors during 28 years of follow-up, were linked with nation-wide registers on socio-economic covariates, mortality and disease incidence. Logistic regression was used to describe life-style and socio-economic determinants of attrition, and Poisson regression was used...

  2. Vocabulary Attrition among Adult English as a Foreign Language Persian Learners

    Science.gov (United States)

    Asgari, Azadeh; Bin Mustapha, Ghazali

    2010-01-01

    This study aims to investigate the attrition rate of EFL concrete and abstract vocabulary among continuing and non-continuing Iranian female and male English language learners across different proficiency levels. They are students of a University and majored in different fields (between 20 and 25 years old). There was no treatment in this study…

  3. The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Montagnaro, Fabio [Dipartimento di Chimica - Universita degli Studi di Napoli Federico II, Complesso Universitario del Monte di Sant' Angelo, 80126 Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy)

    2010-04-15

    The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination. This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)

  4. The relationship between beginning teachers' stress causes, stress responses, teaching behaviour and attrition

    NARCIS (Netherlands)

    Harmsen, Ruth; Lorenz, Michelle; Maulana, Ridwan; van Veen, Klaas

    2018-01-01

    In this study, the relationships between beginning teachers’ perceived stress causes, stress responses, observed teaching behaviour and attrition is investigated employing structural equation modelling (SEM). A total of 143 BTs were surveyed using the Questionnaire on the Experience and Evaluation

  5. A Self-Regulation-Based eHealth Intervention to Promote a Healthy Lifestyle: Investigating User and Website Characteristics Related to Attrition.

    Science.gov (United States)

    Van der Mispel, Celien; Poppe, Louise; Crombez, Geert; Verloigne, Maïté; De Bourdeaudhuij, Ilse

    2017-07-11

    eHealth interventions can reach large populations and are effective in increasing physical activity (PA) and fruit and vegetable intake. Nevertheless, the effects of eHealth interventions are overshadowed by high attrition rates. Examining more closely when users decide to leave the intervention can help eHealth developers to make informed decisions about which intervention components should be reshaped or simply removed. Investigating which users are more likely to quit an intervention can inform developers about whether and how their intervention should be adapted to specific subgroups of users. This study investigated the pattern of attrition in a Web-based intervention to increase PA, fruit, and vegetable intake. The first aim was to describe attrition rates according to different self-regulation components. A second aim was to investigate whether certain user characteristics are predictors for start session completion, returning to a follow-up session and intervention completion. The sample consisted of 549 adults who participated in an online intervention, based on self-regulation theory, to promote PA and fruit and vegetable intake, called "MyPlan 1.0." Using descriptive analysis, attrition was explored per self-regulation component (eg, action planning and coping planning). To identify which user characteristics predict completion, logistic regression analyses were conducted. At the end of the intervention program, there was an attrition rate of 78.2% (330/422). Attrition rates were very similar for the different self-regulation components. However, attrition levels were higher for the fulfillment of questionnaires (eg, to generate tailored feedback) than for the more interactive components. The highest amount of attrition could be observed when people were asked to make their own action plan. There were no significant predictors for first session completion. Yet, two subgroups had a lower chance to complete the intervention, namely male users (OR: 2.24, 95

  6. The Case for Increasing Workplace Decision-Making: Proposing a Model for Special Educator Attrition Research

    Science.gov (United States)

    Tyler, Teresa A.; Brunner, C. Cryss

    2014-01-01

    The chronically high rate of special educator attrition across U.S. schools creates a dilemma for educational leaders because special educators provide direct services to students with special needs. Attrition exacerbates already high special educator shortages reported in most districts, and nearly one million schoolchildren with disabilities…

  7. Attrition of Knowledge Workforce in Healthcare in Northern parts of India – Health Information Technology as a Plausible Retention Strategy

    Directory of Open Access Journals (Sweden)

    Indrajit Bhattacharya

    2012-06-01

    Full Text Available Faced with a global shortage of skilled health workers due to attrition, countries are struggling to build and maintain optimum knowledge workforce in healthcare for delivering quality healthcare services. Forces that affect healthcare professionals’ turnover needs to be addressed before a competent uniformly adoptable strategy could be proposed for mitigating the problem. In this study we investigate the effects of the socio–demographic characteristics on attrition of healthcare knowledge workforce in northern parts of India that have a wide gradient of rural and urban belt, taking into account both public and private healthcare organizations. For this purpose healthcare professional attrition tracking survey (HATS was designed. The data has been collected from a random sample of 807 respondents consisting of doctors, nurses, paramedics and administrators to explore the relationships between various factors acting as antecedents in affecting the job satisfaction, commitment and intention of a healthcare professional to stay in the job. Structured questionnaires were utilized as the data collection tools. Descriptive statistics, factor analysis and path analysis were carried out using multiple regression and correlation to propose a model that best explains the theoretical assumption of factors leading to attrition. Six factors of attrition namely compensation and perks, work life balance, sense of accomplishment, work load, need for automation and technology improvement, substandard nature of work have been identified as the main factors with a data reliability of 0.809%. It has also been identified that the intention to shift is a major decision maker that affects attrition and in turn affected by job satisfaction dimensions. Based on the survey response and analysis, a highly possible strategy of utilizing information technology implementation for increasing worker motivation, job satisfaction and commitment to reduce attrition has been

  8. Increased prevalence of pregnancy and comparative risk of program attrition among individuals starting HIV treatment in East Africa.

    Directory of Open Access Journals (Sweden)

    Charles B Holmes

    Full Text Available The World Health Organization now recommends initiating all pregnant women on life-long antiretroviral therapy (ART, yet there is limited information about the characteristics and program outcomes of pregnant women already on ART in Africa. Our hypothesis was that pregnant women comprised an increasing proportion of those starting ART, and that sub-groups of these women were at higher risk for program attrition.We used the International Epidemiology Databases to Evaluate AIDS- East Africa (IeDEA-EA to conduct a retrospective cohort study including HIV care and treatment programs in Kenya, Uganda, and Tanzania. The cohort consecutively included HIV-infected individuals 13 years or older starting ART 2004-2014. We examined trends over time in the proportion pregnant, their characteristics and program attrition rates compared to others initiating and already receiving ART. 156,474 HIV-infected individuals (67.0% women started ART. The proportion of individuals starting ART who were pregnant women rose from 5.3% in 2004 to 12.2% in 2014. Mean CD4 cell counts at ART initiation, weighted for annual program size, increased from 2004 to 2014, led by non-pregnant women (annual increase 20 cells/mm3 and men (17 cells/mm3 annually, with lower rates of change in pregnant women (10 cells/mm3 per year (p<0.0001. There was no significant difference in the cumulative incidence of program attrition at 6 months among pregnant women starting ART and non-pregnant women. However, healthy pregnant women starting ART (WHO stage 1/2 had a higher rate of attrition rate (9.6%, compared with healthy non-pregnant women (6.5%; in contrast among women with WHO stage 3/4 disease, pregnant women had lower attrition (8.4% than non-pregnant women (14.4%. Among women who initiated ART when healthy and remained in care for six months, subsequent six-month attrition was slightly higher among pregnant women at ART start (3.5% compared to those who were not pregnant (2.4%, (absolute

  9. Increased prevalence of pregnancy and comparative risk of program attrition among individuals starting HIV treatment in East Africa.

    Science.gov (United States)

    Holmes, Charles B; Yiannoutsos, Constantin T; Elul, Batya; Bukusi, Elizabeth; Ssali, John; Kambugu, Andrew; Musick, Beverly S; Cohen, Craig; Williams, Carolyn; Diero, Lameck; Padian, Nancy; Wools-Kaloustian, Kara K

    2018-01-01

    The World Health Organization now recommends initiating all pregnant women on life-long antiretroviral therapy (ART), yet there is limited information about the characteristics and program outcomes of pregnant women already on ART in Africa. Our hypothesis was that pregnant women comprised an increasing proportion of those starting ART, and that sub-groups of these women were at higher risk for program attrition. We used the International Epidemiology Databases to Evaluate AIDS- East Africa (IeDEA-EA) to conduct a retrospective cohort study including HIV care and treatment programs in Kenya, Uganda, and Tanzania. The cohort consecutively included HIV-infected individuals 13 years or older starting ART 2004-2014. We examined trends over time in the proportion pregnant, their characteristics and program attrition rates compared to others initiating and already receiving ART. 156,474 HIV-infected individuals (67.0% women) started ART. The proportion of individuals starting ART who were pregnant women rose from 5.3% in 2004 to 12.2% in 2014. Mean CD4 cell counts at ART initiation, weighted for annual program size, increased from 2004 to 2014, led by non-pregnant women (annual increase 20 cells/mm3) and men (17 cells/mm3 annually), with lower rates of change in pregnant women (10 cells/mm3 per year) (p<0.0001). There was no significant difference in the cumulative incidence of program attrition at 6 months among pregnant women starting ART and non-pregnant women. However, healthy pregnant women starting ART (WHO stage 1/2) had a higher rate of attrition rate (9.6%), compared with healthy non-pregnant women (6.5%); in contrast among women with WHO stage 3/4 disease, pregnant women had lower attrition (8.4%) than non-pregnant women (14.4%). Among women who initiated ART when healthy and remained in care for six months, subsequent six-month attrition was slightly higher among pregnant women at ART start (3.5%) compared to those who were not pregnant (2.4%), (absolute

  10. Attitudes of non-practicing chiropractors: a pilot survey concerning factors related to attrition

    Directory of Open Access Journals (Sweden)

    Wyatt Lawrence H

    2010-11-01

    Full Text Available Abstract Background Research into attitudes about chiropractors who are no longer engaged in active clinical practice is non-existent. Yet non-practicing chiropractors (NPCs represent a valid sub-group worthy of study. Aim The purpose of this research was to assess attrition attitudes of NPCs about the chiropractic profession and develop a scale to assess such attitudes. Methods A 48 item survey was developed using the PsychData software. This survey included 35 Likert-style items assessing various aspects of the profession namely financial, educational, psychosocial and political. An internet discussion site where NPCs may be members was accessed for recruitment purposes. Results A total of 70 valid responses were received for analysis. A majority of respondents were male with 66% being in non-practice status for 3 to 5 years and less with 43% indicating that they had graduated since the year 2000. Most respondents were employed either in other healthcare professions and non-chiropractic education. A majority of NPCs believed that business ethics in chiropractic were questionable and that overhead expense and student loans were factors in practice success. A majority of NPCs were in associate practice at one time with many believing that associates were encouraged to prolong the care of patients and that associate salaries were not fair. Most NPCs surveyed believed that chiropractic was not a good career choice and would not recommend someone to become a chiropractor. From this survey, a 12 item scale was developed called the "chiropractor attrition attitude scale" for future research. Reliability analysis of this novel scale demonstrated a coefficient alpha of 0.90. Conclusion The low response rate indicates that findings cannot be generalized to the NPC population. This study nonetheless demonstrates that NPCs attrition attitudes can be assessed. The lack of a central database of NPCs is a challenge to future research. Appropriate

  11. Attrition in Chronic Disease Self-Management Programs and Self-Efficacy at Enrollment

    Science.gov (United States)

    Verevkina, Nina; Shi, Yunfeng; Fuentes-Caceres, Veronica Alejandra; Scanlon, Dennis Patrick

    2014-01-01

    Among other goals, the Chronic Disease Self-Management Program (CDSMP) is designed to improve self-efficacy of the chronically ill. However, a substantial proportion of the enrollees often leave CDSMPs before completing the program curriculum. This study examines factors associated with program attrition in a CDSMP implemented in a community…

  12. Minimising Attrition: Strategies for Assisting Students Who Are at Risk of Withdrawal

    Science.gov (United States)

    Park, Caroline L.; Perry, Beth; Edwards, Margaret

    2011-01-01

    This paper explores strategies aimed at minimising attrition by encouraging persistence among online graduate students who are considering withdrawal. It builds upon earlier studies conducted by a team of researchers who teach online graduate students in health care at Athabasca University. First, in 2008-2009, Park, Boman, Care, Edwards, and…

  13. Attrition and success rates of accelerated students in nursing courses: a systematic review

    OpenAIRE

    Doggrell, Sheila Anne; Schaffer, Sally

    2016-01-01

    Background There is a comprehensive literature on the academic outcomes (attrition and success) of students in traditional/baccalaureate nursing programs, but much less is known about the academic outcomes of students in accelerated nursing programs. The aim of this systematic review is to report on the attrition and success rates (either internal examination or NCLEX-RN) of accelerated students, compared to traditional students. Methods For the systematic review, the databases (Pubmed, Cinah...

  14. Causes of Teacher Attrition of First, Second, and Third Year Teachers in Rural Middle Schools

    Science.gov (United States)

    Thompson, Arkeco Lashay Lewis

    2012-01-01

    Early attrition from teaching bears enormous costs. High attrition means that schools must take funds urgently needed for school improvements and spend them instead in a manner that produces little long-term payoff for student learning (Kain & Singleton, 1996). Keeping highly qualified teachers should always be at the top of the priority list…

  15. Journey to Becoming a Thai English Teacher: New Perspective on Investigating Teacher Attrition

    Science.gov (United States)

    Prabjandee, Denchai

    2014-01-01

    In this study, the author provides a unique perspective on teacher shortage by focusing on teacher retention, in terms of why teachers stay in the teaching profession, rather than focusing on teacher attrition, or why teachers leave the teaching profession. The change in perspective created an opportunity to study the journey of how teachers chose…

  16. Predicting the Risk of Attrition for Undergraduate Students with Time Based Modelling

    Science.gov (United States)

    Chai, Kevin E. K.; Gibson, David

    2015-01-01

    Improving student retention is an important and challenging problem for universities. This paper reports on the development of a student attrition model for predicting which first year students are most at-risk of leaving at various points in time during their first semester of study. The objective of developing such a model is to assist…

  17. "Should I Stay or Should I Go?": Unpacking Teacher Attrition/Retention as an Educational Issue

    Science.gov (United States)

    Kelchtermans, Geert

    2017-01-01

    The paper starts from the observation that teacher attrition/retention seems to be a wicked issue: it seems to have strong face validity and a commonsense meaning, but the literature doesn't provide a clear and distinctive definition. In the first section, the author analyzes the different ways in which the issue of teacher attrition and retention…

  18. Reliability and Cost Impacts for Attritable Systems

    Science.gov (United States)

    2017-03-23

    on reliability and cost: a probabilistic model. Electric Power Systems Research, 72(3), 213-224. Kalbfleisch, J.D. & Prentice, R.L. (1980). The...copyright protection in the United States. AFIT-ENV-MS-17-M-172 RELIABILITY AND COST IMPACTS FOR ATTRITABLE SYSTEMS THESIS Presented to... power of discrete time Markov chains, whether homogeneous or non-homogeneous, to model the reliability and dependability of repairable systems should

  19. A crowdsourced nickel-and-dime approach to analog OBM research: A behavioral economic framework for understanding workforce attrition.

    Science.gov (United States)

    Henley, Amy J; DiGennaro Reed, Florence D; Reed, Derek D; Kaplan, Brent A

    2016-09-01

    Incentives are a popular method to achieve desired employee performance; however, research on optimal incentive magnitude is lacking. Behavioral economic demand curves model persistence of responding in the face of increasing cost and may be suitable to examine the reinforcing value of incentives on work performance. The present use-inspired basic study integrated an experiential human operant task within a crowdsourcing platform to evaluate the applicability of behavioral economics for quantifying changes in workforce attrition. Participants included 88 Amazon Mechanical Turk Workers who earned either a $0.05 or $0.10 incentive for completing a progressively increasing response requirement. Analyses revealed statistically significant differences in breakpoint between the two groups. Additionally, a novel translation of the Kaplan-Meier survival-curve analyses for use within a demand curve framework allowed for examination of elasticity of workforce attrition. Results indicate greater inelastic attrition in the $0.05 group. We discuss the benefits of a behavioral economic approach to modeling employee behavior, how the metrics obtained from the elasticity of workforce attrition analyses (e.g., P max ) may be used to set goals for employee behavior while balancing organizational costs, and how economy type may have influenced observed outcomes. © 2016 Society for the Experimental Analysis of Behavior.

  20. High attrition among HIV-infected patients with advanced disease treated in an intermediary referral center in Maputo, Mozambique

    Directory of Open Access Journals (Sweden)

    Lucas Molfino

    2014-04-01

    Full Text Available Background: In Mozambique, antiretroviral therapy (ART scale-up has been successfully implemented. However, attrition in care remains a major programmatic challenge. In 2009, an intermediary-level HIV referral center was created in Maputo to ensure access to specialized care for HIV-infected patients with complications (advanced clinical-immunological stage, Kaposi sarcoma, or suspected ART failure. Objective: To determine the attrition from care and to identify risk factors that lead to high attrition among patients referred to an intermediary-level HIV referral center. Design: This was a retrospective cohort study from 2009 to 2011. Results: A total of 1,657 patients were enrolled, 847 (51% were men, the mean age was 36 years (standard deviation: 11, the mean CD4 count was 27 cells/µl (interquartile range: 11–44, and one-third were severely malnourished. The main reasons for referral were advanced clinical stages (WHO stages 3 and 4, and CD4 count <50 cells/µl in 70% of the cases, and 19% had Kaposi sarcoma. The overall attrition rate was 28.7 per 100 person-years (PYs – the mortality rate was 5.0 (95% confidence interval [CI]: 4.2–5.9 per 100 PYs, and the loss-to-follow-up rate was 23.7 (95% CI: 21.9–25.6 per 100 PYs. There were 793 attritions – 137 deaths and 656 lost to follow-up (LTFU; 77% of all attrition happened within the first year. The factors independently associated with attrition were male sex (adjusted hazard ratio [aHR]: 1.15, 95% CI: 1.0–1.3, low body mass index (aHR: 1.51, 95% CI: 1.2–1.8, WHO clinical stage 3 or 4 (aHR: 1.30, 95% CI: 1.0–1.6; and aHR: 1.91, 95% CI: 1.4–2.5, later year of enrollment (aHR 1.61, 95% CI 1.3–1.9, and ‘being already on ART’ at enrollment (aHR 13.71, 95% CI 11.4–16.4. Conclusions: Attrition rates among HIV-infected patients enrolled in an intermediary referral center were high, mainly related to advanced stage of clinical disease. Measures are required to address this

  1. Engagement and Nonusage Attrition With a Free Physical Activity Promotion Program: The Case of 10,000 Steps Australia.

    Science.gov (United States)

    Guertler, Diana; Vandelanotte, Corneel; Kirwan, Morwenna; Duncan, Mitch J

    2015-07-15

    Data from controlled trials indicate that Web-based interventions generally suffer from low engagement and high attrition. This is important because the level of exposure to intervention content is linked to intervention effectiveness. However, data from real-life Web-based behavior change interventions are scarce, especially when looking at physical activity promotion. The aims of this study were to (1) examine the engagement with the freely available physical activity promotion program 10,000 Steps, (2) examine how the use of a smartphone app may be helpful in increasing engagement with the intervention and in decreasing nonusage attrition, and (3) identify sociodemographic- and engagement-related determinants of nonusage attrition. Users (N=16,948) were grouped based on which platform (website, app) they logged their physical activity: Web only, app only, or Web and app. Groups were compared on sociodemographics and engagement parameters (duration of usage, number of individual and workplace challenges started, and number of physical activity log days) using ANOVA and chi-square tests. For a subsample of users that had been members for at least 3 months (n=11,651), Kaplan-Meier survival curves were estimated to plot attrition over the first 3 months after registration. A Cox regression model was used to determine predictors of nonusage attrition. In the overall sample, user groups differed significantly in all sociodemographics and engagement parameters. Engagement with the program was highest for Web-and-app users. In the subsample, 50.00% (5826/11,651) of users stopped logging physical activity through the program after 30 days. Cox regression showed that user group predicted nonusage attrition: Web-and-app users (hazard ratio=0.86, 95% CI 0.81-0.93, Pworkplace challenges (hazard ratio=0.94, 95% CI 0.90-0.97, Pphysical activity logging days (hazard ratio=0.921, 95% CI 0.919-0.922, P<.001), and steps logged per day (hazard ratio=0.99999, 95% CI 0

  2. In Their Own Words: A Text Analytics Investigation of College Course Attrition

    Science.gov (United States)

    Michalski, Greg V.

    2014-01-01

    Excessive course attrition is costly to both the student and the institution. While most institutions have systems to quantify and report the numbers, far less attention is typically paid to each student's reason(s) for withdrawal. In this case study, text analytics was used to analyze a large set of open-ended written comments in which students…

  3. A Qualitative Evaluation of Engagement and Attrition in a Nurse Home Visiting Program: From the Participant and Provider Perspective.

    Science.gov (United States)

    Beasley, Lana O; Ridings, Leigh E; Smith, Tyler J; Shields, Jennifer D; Silovsky, Jane F; Beasley, William; Bard, David

    2018-05-01

    Beginning parenting programs in the prenatal and early postnatal periods have a large potential for impact on later child and maternal outcomes. Home-based parenting programs, such as the Nurse Family Partnership (NFP), have been established to help address this need. Program reach and impact is dependent on successful engagement of expecting mothers with significant risks; however, NFP attrition rates remain high. The current study qualitatively examined engagement and attrition from the perspectives of NFP nurses and mothers in order to identify mechanisms that enhance service engagement. Semi-structured interviews were conducted in focus groups composed of either engaged (27 total mothers) or unengaged (15 total mothers) mothers from the NFP program. NFP nurses (25 total nurses) were recruited for individual semi-structured interviews. Results suggest that understanding engagement in the NFP program requires addressing both initial and sustained engagement. Themes associated with enhanced initial engagement include nurse characteristics (e.g., flexible, supportive, caring) and establishment of a solid nurse-family relationship founded on these characteristics. Factors impacting sustained engagement include nurse characteristics, provision of educational materials on child development, individualized services for families, and available family support. Identified barriers to completing services include competing demands and lack of support. Findings of this study have direct relevance for workforce planning, including hiring and training through integrating results regarding effective nurse characteristics. Additional program supports to enhance parent engagement may be implemented across home-based parenting programs in light of the current study's findings.

  4. Predicting Attrition, Performance, Reenlistment, and Hospitalizations from the Smoking History of Women Prior to Entering the Navy

    National Research Council Canada - National Science Library

    Conway, Terry L

    2006-01-01

    This study of women sailors examined whether tobacco use prior to entering the Navy predicted subsequent career outcomes related to length of service, early attrition, misconduct, and hospitalizations...

  5. Initial Entry Training: Reducing First Term Attrition Through Effective Organizational Socialization

    National Research Council Canada - National Science Library

    Hayden, Thomas

    2000-01-01

    .... Behavioral scientist claim that attrition in organizations can be attributed to many factors such as lack of commitment to the organization, poor skill development, mismatch in employee expectations...

  6. Attrition of schistosomes in an irradiation-attenuated cercarial immunization model of Schistosoma mansoni

    International Nuclear Information System (INIS)

    Stek, M. Jr.; Dean, D.A.; Clark, S.S.

    1981-01-01

    The attrition of Schistosoma mansoni challenge worms was studied in irradiation-attenuated cercaria-immunized mice as a function of site and time. The peak recovery of schistosomula from the lungs of immunized mice was delayed 2 days in comparison with non-immunized controls. The difference between the peak recoveries of control and immunized mice accounted for about half of the final attrition observed at the 7-week adult worm stge. Hepatic-mesenteric vein worm recoveries obtained 10 to 42 days after challenge were reduced in most cases at least as much as the 49-day counts. Somewhat higher reductions were observed at 14 to 28 days than at 49 days, confirming the evidence of delayed migration obtained at the lung phase. These findings, coupled with histologic observations, indicate that at least half of the worm elimination attributable to immunization occurs 8 or more days after the challenge infection

  7. Treatment initiation, program attrition and patient treatment outcomes associated with scale-up and decentralization of HIV care in rural Malawi.

    Directory of Open Access Journals (Sweden)

    Megan McGuire

    Full Text Available OBJECTIVE: To describe patient antiretroviral therapy (cART outcomes associated with intensive decentralization of services in a rural HIV program in Malawi. METHODS: Longitudinal analysis of data from HIV-infected patients starting cART between August 2001 and December 2008 and of a cross-sectional immunovirological assessment conducted 12 (±2 months after therapy start. One-year mortality, lost to follow-up, and attrition (deaths and lost to follow-up rates were estimated with exact Poisson 95% confidence intervals (CI by type of care delivery and year of initiation. Association of virological suppression (<50 copies/mL and immunological success (CD4 gain ≥100 cells/µL, with type of care was investigated using multiple logistic regression. RESULTS: During the study period, 4322 cART patients received centralized care and 11,090 decentralized care. At therapy start, patients treated in decentralized health facilities had higher median CD4 count levels (167 vs. 130 cell/µL, P<0.0001 than other patients. Two years after cART start, program attrition was lower in decentralized than centralized facilities (9.9 per 100 person-years, 95% CI: 9.5-10.4 vs. 20.8 per 100 person-years, 95% CI: 19.7-22.0. One year after treatment start, differences in immunological success (adjusted OR=1.23, 95% CI: 0.83-1.83, and viral suppression (adjusted OR=0.80, 95% CI: 0.56-1.14 between patients followed at centralized and decentralized facilities were not statistically significant. CONCLUSIONS: In rural Malawi, 1- and 2-year program attrition was lower in decentralized than in centralized health facilities and no statistically significant differences in one-year immunovirological outcomes were observed between the two health care levels. Longer follow-up is needed to confirm these results.

  8. Averting the Train Wreck of Captain Attrition - A Leadership Solution

    National Research Council Canada - National Science Library

    Weafer, Thomas

    2001-01-01

    .... This paper looks at officer attrition in the context of a leadership challenge - it examines current perceived problems in leadership culture and command climate and recommends several changes focused on improving morale and retention of young officers.

  9. Optimizing removal of arsenic, chromium, copper, pentachlorophenol and polychlorodibenzo-dioxins/furans from the 1-4 mm fraction of polluted soil using an attrition process.

    Science.gov (United States)

    Guemiza, Karima; Coudert, Lucie; Tran, Lan Huong; Metahni, Sabrine; Blais, Jean-François; Besner, Simon; Mercier, Guy

    2017-08-01

    The objective of this study was to evaluate, at a pilot scale, the performance of an attrition process for removing As, Cr, Cu, pentachlorophenol (PCP) and polychlorodibenzodioxins and furans (PCDDF) from a 1-4 mm soil fraction. A Box-Behnken experimental design was utilized to evaluate the influence of several parameters (temperature, surfactant concentration and pulp density) and to optimize the main operating parameters of this attrition process. According to the results, the concentration of surfactant (cocamidopropylbetaine-BW) was the main parameter influencing both PCP and PCDDF removal from the 1-4 mm soil fraction by attrition. The behavior of each 2,3,7,8-PCDD/F congener during the attrition process was studied. The results indicated that the concentration of surfactant had a significant and positive effect on the removal of almost all of the dioxin and furan. The removal of 56%, 55%, 50%, 67% and 62% of the contaminants were obtained for As, Cr, Cu, PCP and PCDDF, respectively, using the optimized conditions ([BW]= 2% (w.w-1), T = 25°C and PD = 40% (w.w-1)). These results showed that attrition in the presence of a surfactant can be efficiently used to remediate the coarse fractions of soil contaminated by As, Cr, Cu, PCP and PCDDF.

  10. COMPENSATORY STRATEGIES OF FIRST-LANGUAGE-ATTRITED CHILDREN

    Directory of Open Access Journals (Sweden)

    Syahdan Syahdan

    2012-01-01

    Full Text Available This article explores the compensatory strategies used by two Indonesian children who experienced first language attrition when acquiring English in the English-speaking environment. They use compensatory strategies to compensate for their lack of competence in first language. They employ both interlingual strategies and discourse strategies when they have difficulties in communication. Interlingual strategies used are codeswitching and lexical borrowings and the discourse strategies are overt comments, appeal for assistance, and avoidance.

  11. Relationship between Academic Performance, Spatial Competence, Learning Styles and Attrition

    Directory of Open Access Journals (Sweden)

    Marianela Noriega Biggio

    2013-04-01

    Full Text Available This paper discusses the results of research on factors affecting academic performance and attrition in a sample of 1,500 freshman students majoring in architecture, design and urbanism at the Universidad de Buenos Aires, Argentina [University of Buenos Aires, Argentina] who were enrolled in a drafting course. The hypotheses we tested concern the mediating role of learning styles on the relationship between spatial competence and academic performance, learning-style differences by gender and cohort, and the relationship between attrition, spatial competence level and learning style. Statistical analysis of the data was performed and spatial competence enhanced by motivational profile was found to predict final achievement. Educational implications are identified, highlighting the need to promote in students those academic behaviors that characterize a self-regulated learning style and encourage the use of specific intellectual abilities.

  12. An Exploration of Teacher Attrition and Mobility in High Poverty Racially Segregated Schools

    Science.gov (United States)

    Djonko-Moore, Cara M.

    2016-01-01

    The purpose of this study was to examine the mobility (movement to a new school) and attrition (quitting teaching) patterns of teachers in high poverty, racially segregated (HPRS) schools in the US. Using 2007-9 survey data from the National Center for Education Statistics, a multi-level multinomial logistic regression was performed to examine the…

  13. Survey on workforce retention and attrition

    Science.gov (United States)

    Showstack, Randy

    2013-03-01

    The Society of Petroleum Engineers (SPE) is conducting a survey to gather information on why technical professionals change jobs or quit working. The survey, prompted by concern about the retention of skilled workers, aims to provide information to employers that can assist them in addressing practices that can lead to significant workforce attrition. To participate in the survey, which is open to everyone (including those who are not SPE members), go to http://research.spe.org/se.ashx?s=705E3F1335720258 through 15 May 2013. For more information, contact speresearch@spe.org.

  14. The Career Officer Attrition Dilemma: An Underlying Cause

    Science.gov (United States)

    2002-04-09

    BOOMER, XER, & MILLENIAL TRAITS COMPARISON ..................................... 23 vii viii THE CAREER OFFICER ATTRITION DILEMMA: AN UNDERLYING...provide a sustainable solution. Multiple generations in the military will always be present. What will change, however, is which generation will be in the... MILLENIAL TRAITS COMPARISON cause serious frustration both for the senior leadership and their subordinates. Even as the Xers begin to take over from

  15. Sex offender risk assessment: the need to place recidivism research in the context of attrition in the criminal justice system.

    Science.gov (United States)

    Larcombe, Wendy

    2012-04-01

    Jurisdictions in the United States, United Kingdom, and Australia now have laws that enable preventive detention of post-sentence sex offenders based on an assessment of the offender's likely recidivism. Measures of recidivism, or risk assessments, rely on the criminal justice process to produce the "pool" of sex offenders studied. This article argues that recidivism research needs to be placed in the context of attrition studies that document the disproportionate and patterned attrition of sexual offenses and sexual offenders from the criminal justice process. Understanding the common biases that affect criminal prosecution of sex offenses would improve sexual violence prevention policies.

  16. Analytical modelling for ultrasonic surface mechanical attrition treatment

    Directory of Open Access Journals (Sweden)

    Guan-Rong Huang

    2015-07-01

    Full Text Available The grain refinement, gradient structure, fatigue limit, hardness, and tensile strength of metallic materials can be effectively enhanced by ultrasonic surface mechanical attrition treatment (SMAT, however, never before has SMAT been treated with rigorous analytical modelling such as the connection among the input energy and power and resultant temperature of metallic materials subjected to SMAT. Therefore, a systematic SMAT model is actually needed. In this article, we have calculated the averaged speed, duration time of a cycle, kinetic energy and kinetic energy loss of flying balls in SMAT for structural metallic materials. The connection among the quantities such as the frequency and amplitude of attrition ultrasonic vibration motor, the diameter, mass and density of balls, the sample mass, and the height of chamber have been considered and modelled in details. And we have introduced the one-dimensional heat equation with heat source within uniform-distributed depth in estimating the temperature distribution and heat energy of sample. In this approach, there exists a condition for the frequency of flying balls reaching a steady speed. With these known quantities, we can estimate the strain rate, hardness, and grain size of sample.

  17. Teacher Attrition Variables That Influence Retention and Job Satisfaction

    Science.gov (United States)

    Butler, Leslie Garmon

    2014-01-01

    Teacher attrition is a major problem. According to researchers at North Carolina State University, more teachers are leaving the profession than staying or entering. Accordingly, school systems in the United States find themselves in the predicament where they must hire teachers who have little teaching experience or who have not been adequately…

  18. The measurement of change in functional ability: dealing with attrition and the floor/ceiling effect

    DEFF Research Database (Denmark)

    Holstein, Bjørn E; Avlund, Kirsten; Due, Pernille

    2006-01-01

    , functional ability at baseline, relative wealth, social network, self-rated health, and life-satisfaction. Inclusion of the dead in statistical models for the study of change in functional ability reduced the attrition problem. A logistic model for paired observations of functional ability at two points...

  19. Predictors of Attrition in the Finnish Conscript Service

    Science.gov (United States)

    2006-11-01

    Dawson et al., 1994; Kassel, Jackson, & Unrod, 2000; Lazarus & Folkman , 1984; Pierce & Lydon, 1998; Thompson & Gignac, 2001). These expectations toward...organizational socialization. USAWC Strategy Research Project Carlisle Barracks, PA: U.S. Army War College. Hicks, J. M., & Nogami, G. Y . (1984...of Navy attrition. II. A demonstration of potential usefulness for screening. (Report No. 01-06). Military Medicine, 167, 770-776. Lazarus , R. S

  20. Initial Entry Training: Reducing First Term Attrition Through Effective Organizational Socialization

    National Research Council Canada - National Science Library

    Hayden, Thomas

    2000-01-01

    This paper examines Initial Entry Training (IET) from an organizational behavior perspective to identify if the Army's socialization experience can be enhanced to have a positive impact on first term attrition within the Army...

  1. Determinants of Attrition to Follow-Up in a Multicentre Cohort Study in Children-Results from the IDEFICS Study

    DEFF Research Database (Denmark)

    Hense, Sabrina; Pohlabeln, Hermann; Michels, Nathalie

    2013-01-01

    (OR = 1.46; 99% CI: 1.19, 1.79) was lacking. Drop-out proportion rose with the number of missing items. Overweight, low education, single parenthood and low well-being scores were independent determinants of attrition. Baseline participation, and the individual determinant effects seemed unrelated...... at 훼 = 0 . 0 1 to account for the large sample size. The strongest associations were seen for baseline item non-response, especially when information on migration background (odds ratio (OR) = 1.55; 99% confidence interval (CI): 1.04, 2.31), single parenthood (OR = 1.37; 99% CI: 1.12, 1.67), or well-being...

  2. Retention and risk factors for attrition in a large public health ART program in Myanmar: a retrospective cohort analysis.

    Science.gov (United States)

    Thida, Aye; Tun, Sai Thein Than; Zaw, Sai Ko Ko; Lover, Andrew A; Cavailler, Philippe; Chunn, Jennifer; Aye, Mar Mar; Par, Par; Naing, Kyaw Win; Zan, Kaung Nyunt; Shwe, Myint; Kyaw, Thar Tun; Waing, Zaw Htoon; Clevenbergh, Philippe

    2014-01-01

    The outcomes from an antiretroviral treatment (ART) program within the public sector in Myanmar have not been reported. This study documents retention and the risk factors for attrition in a large ART public health program in Myanmar. A retrospective analysis of a cohort of adult patients enrolled in the Integrated HIV Care (IHC) Program between June 2005 and October 2011 and followed up until April 2012 is presented. The primary outcome was attrition (death or loss-follow up); a total of 10,223 patients were included in the 5-year cumulative survival analysis. Overall 5,718 patients were analyzed for the risk factors for attrition using both logistic regression and flexible parametric survival models. The mean age was 36 years, 61% of patients were male, and the median follow up was 13.7 months. Overall 8,564 (84%) patients were retained in ART program: 750 (7%) were lost to follow-up and 909 (9%) died. During the 3 years follow-up, 1,542 attritions occurred over 17,524 person years at risk, giving an incidence density of 8.8% per year. The retention rates of participants at 12, 24, 36, 48 and 60 months were 86, 82, 80, 77 and 74% respectively. In multivariate analysis, being male, having high WHO staging, a low CD4 count, being anaemic or having low BMI at baseline were independent risk factors for attrition; tuberculosis (TB) treatment at ART initiation, a prior ART course before program enrollment and literacy were predictors for retention in the program. High retention rate of IHC program was documented within the public sector in Myanmar. Early diagnosis of HIV, nutritional support, proper investigation and treatment for patients with low CD4 counts and for those presenting with anaemia are crucial issues towards improvement of HIV program outcomes in resource-limited settings.

  3. Retention and risk factors for attrition in a large public health ART program in Myanmar: a retrospective cohort analysis.

    Directory of Open Access Journals (Sweden)

    Aye Thida

    Full Text Available BACKGROUND: The outcomes from an antiretroviral treatment (ART program within the public sector in Myanmar have not been reported. This study documents retention and the risk factors for attrition in a large ART public health program in Myanmar. METHODS: A retrospective analysis of a cohort of adult patients enrolled in the Integrated HIV Care (IHC Program between June 2005 and October 2011 and followed up until April 2012 is presented. The primary outcome was attrition (death or loss-follow up; a total of 10,223 patients were included in the 5-year cumulative survival analysis. Overall 5,718 patients were analyzed for the risk factors for attrition using both logistic regression and flexible parametric survival models. RESULT: The mean age was 36 years, 61% of patients were male, and the median follow up was 13.7 months. Overall 8,564 (84% patients were retained in ART program: 750 (7% were lost to follow-up and 909 (9% died. During the 3 years follow-up, 1,542 attritions occurred over 17,524 person years at risk, giving an incidence density of 8.8% per year. The retention rates of participants at 12, 24, 36, 48 and 60 months were 86, 82, 80, 77 and 74% respectively. In multivariate analysis, being male, having high WHO staging, a low CD4 count, being anaemic or having low BMI at baseline were independent risk factors for attrition; tuberculosis (TB treatment at ART initiation, a prior ART course before program enrollment and literacy were predictors for retention in the program. CONCLUSION: High retention rate of IHC program was documented within the public sector in Myanmar. Early diagnosis of HIV, nutritional support, proper investigation and treatment for patients with low CD4 counts and for those presenting with anaemia are crucial issues towards improvement of HIV program outcomes in resource-limited settings.

  4. Factors Influencing Students' Attrition at Sultan Qaboos University (SQU)

    Science.gov (United States)

    Al Ghanboosi, Salim Saleen

    2013-01-01

    The students' attrition rates among students enrolled at SQU ranged between 6.8% (1998), 7.8% (1999), and 7.9% (2000). However, the drop-out rate at the Sultan Qaboos University is increasing gradually, and this increase represents a problem for the university that provides free education and financial aid for all male students coming from areas…

  5. Schistosoma mansoni: migration and attrition of irradiated and challenge schistosomula in the mouse

    Energy Technology Data Exchange (ETDEWEB)

    Mastin, A.J.; Wilson, R.A. (York Univ. (UK)); Bickle, Q.D. (Winches Farm Field Station, St. Albans (UK))

    1983-08-01

    The fate of irradiated, immunizing cercariae and challenge schistosomula was investigated in mice using a quantitative, histological technique which would appear to be more efficient in estimating parasite numbers in skin and lungs than does the tissue mincing and incubation recovery technique used previously by other workers. There was evidence for slight retardation of irradiated parasite migration in skin, but death of schistosomula in the skin appeared negligible. The majority of irradiated parasites remained in the lungs until at least day 21 after infection, and that most schistosomula observed at this time were dead. In mice immunized with irradiated cercariae there was no evidence of attrition of the challenge infection in the skin. The migration profile of challenge parasites in the lungs of immunized animals was not significantly different from that of normal parasites in the lungs of naive animals. Dead challenge parasites were observed in the lungs but their numbers were not considered great enough to account for the final attrition measured by perfusion. It is suggested that the remainder of the attrition of challenge schistosomula may occur in the systemic and/or hepatic portal circulation.

  6. Schistosoma mansoni: migration and attrition of irradiated and challenge schistosomula in the mouse

    International Nuclear Information System (INIS)

    Mastin, A.J.; Wilson, R.A.; Bickle, Q.D.

    1983-01-01

    The fate of irradiated, immunizing cercariae and challenge schistosomula was investigated in mice using a quantitative, histological technique which would appear to be more efficient in estimating parasite numbers in skin and lungs than does the tissue mincing and incubation recovery technique used previously by other workers. There was evidence for slight retardation of irradiated parasite migration in skin, but death of schistosomula in the skin appeared negligible. The majority of irradiated parasites remained in the lungs until at least day 21 after infection, and that most schistosomula observed at this time were dead. In mice immunized with irradiated cercariae there was no evidence of attrition of the challenge infection in the skin. The migration profile of challenge parasites in the lungs of immunized animals was not significantly different from that of normal parasites in the lungs of naive animals. Dead challenge parasites were observed in the lungs but their numbers were not considered great enough to account for the final attrition measured by perfusion. It is suggested that the remainder of the attrition of challenge schistosomula may occur in the systemic and/or hepatic portal circulation. (author)

  7. How can attrition rates be reduced in cancer drug discovery?

    Science.gov (United States)

    Moreno, Lucas; Pearson, Andrew D J

    2013-04-01

    Attrition is a major issue in anticancer drug development with up to 95% of drugs tested in Phase I trials not reaching a marketing authorisation making the drug development process enormously costly and inefficient. It is essential that this problem is addressed throughout the whole drug development process to improve efficiency which will ultimately result in increased patient benefit with more profitable drugs. The approach to reduce cancer drug attrition rates must be based on three pillars. The first of these is that there is a need for new pre-clinical models which can act as better predictors of success in clinical trials. Furthermore, clinical trials driven by tumour biology with the incorporation of predictive and pharmacodynamic biomarkers would be beneficial in drug development. Finally, there is a need for increased collaboration to combine the unique strengths between industry, academia and regulators to ensure that the needs of all stakeholders are met.

  8. Delineating the third age: joint models of older people's quality of life and attrition in Britain 2002-2010.

    Science.gov (United States)

    Tampubolon, Gindo

    2015-07-01

    In the public mind, later life is being transformed by the emerging possibility of a flourishing third age with sustained quality of life. We draw trajectories of life quality measured using CASP-19 over eight years. We refine these trajectories by jointly modelling attrition, since older people tend to leave longitudinal studies (attrite) not at random. Growth curve models are applied to the English Longitudinal Study of Ageing waves 1 to 5. Then joint model is estimated where attrition is considered. Extensive predictors are entered including demographic attributes, social and economic status, health conditions, and behaviours. Strong non-linear age trajectory of life quality is revealed by the growth curve models where the peak is achieved in the late 60s. Then the joint model uncovers the peak somewhat later in time, and also reveals secular improvement in life quality experienced by recent cohorts. Sharp estimates for many predictors of higher levels of life quality are also found. For the first time, the trajectories of life quality in the third age are drawn and improvement across cohorts is demonstrated. The contributions are estimated for predictors amenable to intervention such as social capital. This can help in policy discussion on improving the lives of older people in the third age.

  9. Attrition in Chronic Disease Self-Management Programs and self-efficacy at enrollment.

    Science.gov (United States)

    Verevkina, Nina; Shi, Yunfeng; Fuentes-Caceres, Veronica Alejandra; Scanlon, Dennis Patrick

    2014-12-01

    Among other goals, the Chronic Disease Self-Management Program (CDSMP) is designed to improve self-efficacy of the chronically ill. However, a substantial proportion of the enrollees often leave CDSMPs before completing the program curriculum. This study examines factors associated with program attrition in a CDSMP implemented in a community setting. We used data from the Our Pathways to Health program, implemented in Humboldt County, California, from 2008 to 2011. Our conceptual framework is based on Bandura's self-efficacy theory, and we used logistic regression to investigate whether baseline self-efficacy and other members' efficacy are associated with participants dropping out of the CDSMP. Twenty-three percent of the participants did not complete the program similar to previous studies. Lower baseline self-efficacy increased the odds of dropout, but other members' efficacy was not associated with differential odds of dropout. Age, educational difference between the individual and the group, weekday sessions, and social/role activity limitations are also found to be associated with program attrition. Our results suggest that participants with low starting self-efficacy may need extra help to complete the program. Further research is needed to understand how to effectively provide additional support to this group. © 2014 Society for Public Health Education.

  10. The network of corporate clients: customer attrition at commercial banks

    Science.gov (United States)

    Lublóy, Á.; Szenes, M.

    2008-12-01

    Commercial banks might profit from the adoption of methods widely used in network theory. A decision making process might become biased if one disregards network effects within the corporate client portfolio. This paper models the phenomenon of customer attrition by generating a weighted and directed network of corporate clients linked by financial transactions. During the numerical study of the agent-based toy model we demonstrate that multiple steady states may exist. The statistical properties of the distinct steady states show similarities. We show that most companies of the same community choose the same bank in the steady state. In contrast to the case for the steady state of the Barabási-Albert network, market shares in this model equalize by network size. When modeling customer attrition in the network of 3 × 105 corporate clients, none of the companies followed the behavior of the initial switcher in three quarters of the simulations. The number of switchers exceeded 20 in 1% of the cases. In the worst-case scenario a total of 688 companies chose a competitor bank. Significant network effects have been discovered; high correlation prevailed between the degree of the initial switcher and the severity of the avalanche effect. This suggests that the position of the corporate client in the network might be much more important than the underlying properties (industry, size, profitability, etc) of the company.

  11. Lanchester's attrition models and fights among social animals

    OpenAIRE

    Eldridge S. Adams; Michael Mesterton-Gibbons

    2003-01-01

    Lanchester's models of attrition during warfare have served as the basis for several predictions about conflicts between groups of animals. These models and their extensions describe rates of mortality during battles as functions of the number and fighting abilities of individuals in each group, allowing analysis of the determinants of group strength and of the cumulative numbers of casualties. We propose modifications to Lanchester's models to improve their applicability to social animals. I...

  12. Evaluation of the Dehulling Efficiency of Soybean Using Attrition and ...

    African Journals Online (AJOL)

    Conditioned seeds were dehulled in the huller section of commercial rice milling machine and attrition milling machine. A dehulling efficiency (e) value of 55%, which corresponded to an extraction yield (E) of 44% was achieved using the huller section of a commercial rice milling machine, while 90% dehulling efficiency (e), ...

  13. Attrition of Women Business Majors in an Urban Community College.

    Science.gov (United States)

    Karlen, Janice M.

    2004-01-01

    Identified intervention protocols that could help reduce the attrition of women business majors at an urban community college. Review of academic progress data and data from student surveys which examined students' reasons for leaving the institution indicated that there was a need for support mechanisms throughout the freshman year and extending…

  14. The Surgical Personality: Does Surgery Resident Motivation Predict Attrition?

    Science.gov (United States)

    Symer, Matthew M; Abelson, Jonathan S; Yeo, Heather L; Sosa, Julie A; Rosenthal, M Zachary

    2018-05-01

    There is limited understanding of the wide variation in attrition rates among general surgery residencies. We used the validated Behavior Inhibitory System/Behavior Approach System (BIS/BAS) instrument to compare motivational traits among residents who did and not complete surgical training. All US general surgery categorical interns in the class of 2007-2008 were surveyed with a validated motivational trait assessment tool. American Board of Surgery records from 2008-2016 were used to determine who completed training. Motivation, an aspect of personality, was assessed with the BIS/BAS, which correlates with an individual's tendency to approach pleasant stimuli (BAS) or avoid negative stimuli (BIS). Subscale mean scores were compared with regard to the primary end point, attrition. Eight hundred and one (76.5%) interns completed the survey and had matching records. Six hundred and forty-five (80.5%) completed training. Men had lower scores than women in the BAS Drive subscale (12.0 vs 12.5; p scale (19.3 vs 20.9; p academic 17.3 vs community 17.6 vs military 16.6; p motivational personality traits. Copyright © 2018 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  15. The Effects of Turnover: What We Know about Teacher Attrition

    Science.gov (United States)

    DeAngelis, Karen

    2012-01-01

    School business officials are likely to know better than anyone else about the financial costs to districts and schools associated with teacher attrition. Perhaps less well-known, though, is what else has been learned about this issue in recent years--information that may affect how one thinks about teacher turnover. Here is some of that research:…

  16. First-Quarter Academic Performance. Indicators as Predictors of College Attrition: A Study of the 1976-1980 Class at Central State University.

    Science.gov (United States)

    Rodney, Elaine

    The validity of students' first-quarter academic performance in predicting attrition at Central State University, Ohio, was investigated. It was hypothesized that freshmen who performed satisfactorily during the first quarter were more likely to complete their baccalaureate programs than were those who performed less well. Data on 287 students…

  17. Health worker attrition at a rural district hospital in Rwanda: a need ...

    African Journals Online (AJOL)

    Health worker attrition at a rural district hospital in Rwanda: a need for improved placement and retention strategies. Jackline Odhiambo, Felix Cyamatare Rwabukwisi, Christian Rusangwa, Vincent Rusanganwa, Lisa Ruth Hirschhorn, Evrard Nahimana, Patient Ngamije, Bethany Lynn Hedt-Gauthier ...

  18. Military Enlistment and Attrition. An Analysis of Decision Reversal

    Science.gov (United States)

    1987-06-01

    instability, defined as being unemployed at the time of enlistment or having had a spell of jobless- ness within the past 12 months. For graduates, attrition...opportunities. The level of education an individual obtains is related to the value of higher education to the individual (both monetary and psychic ...value, does suggest that unemployed graduates are more likely to enlist, all other things equal, the higher their previous wage rate. The previous

  19. Attrition of memory CD8 T cells during sepsis requires LFA-1.

    Science.gov (United States)

    Serbanescu, Mara A; Ramonell, Kimberly M; Hadley, Annette; Margoles, Lindsay M; Mittal, Rohit; Lyons, John D; Liang, Zhe; Coopersmith, Craig M; Ford, Mandy L; McConnell, Kevin W

    2016-11-01

    CD8 T cell loss and dysfunction have been implicated in the increased susceptibility to opportunistic infections during the later immunosuppressive phase of sepsis, but CD8 T cell activation and attrition in early sepsis remain incompletely understood. With the use of a CLP model, we assessed CD8 T cell activation at 5 consecutive time points and found that activation after sepsis results in a distinct phenotype (CD69 + CD25 int CD62L HI ) independent of cognate antigen recognition and TCR engagement and likely through bystander-mediated cytokine effects. Additionally, we observed that sepsis concurrently results in the preferential depletion of a subset of memory-phenotype CD8 T cells that remain "unactivated" (i.e., fail to up-regulate activation markers) by apoptosis. Unactivated CD44 HI OT-I cells were spared from sepsis-induced attrition, as were memory-phenotype CD8 T cells of mice treated with anti-LFA-1 mAb, 1 h after CLP. Perhaps most importantly, we demonstrate that attrition of memory phenotype cells may have a pathologic significance, as elevated IL-6 levels were associated with decreased numbers of memory-phenotype CD8 T cells in septic mice, and preservation of this subset after administration of anti-LFA-1 mAb conferred improved survival at 7 d. Taken together, these data identify potentially modifiable responses of memory-phenotype CD8 T cells in early sepsis and may be particularly important in the application of immunomodulatory therapies in sepsis. © Society for Leukocyte Biology.

  20. Attrition-free pyrolysis to produce bio-oil and char.

    Science.gov (United States)

    Mauviel, Guillain; Guillain, Mauviel; Kies, Fairouz; Fairouz, Kies; René, Mar Sans; Mar, Sans Rene; Ferrer, Monique; Monique, Ferrer; Lédé, Jacques; Jacques, Lédé

    2009-12-01

    Experiments are performed on a laboratory scale setup where beech wood chips are heated by gas convection and walls radiation. This study shows that it is possible to obtain high bio-oil and char yields with relatively low external heat transfer coefficients. The main advantage of this convection/radiation heat transfer mode compared to solid-solid collisions, applied in fluidized bed or twin screw reactors, is the reduction of solid attrition (char and sand). Thus tricky gas-solid separation through hot cyclones and/or hot filters could be avoided or reduced. It should be possible to recover directly bio-oil with less char particles and char free of sand dust. These qualities would allow easier use of these bio-products in different applications.

  1. A Longitudinal Examination of First Term Attrition and Reenlistment among FY1999 Enlisted Accessions

    National Research Council Canada - National Science Library

    Strickland, William J

    2005-01-01

    .... This effort allowed the evaluation of models of attrition and reenlistment intentions based on information contained in personnel records and collected from Soldiers who were surveyed as they entered...

  2. Faculty Promotion and Attrition: The Importance of Coauthor Network Reach at an Academic Medical Center.

    Science.gov (United States)

    Warner, Erica T; Carapinha, René; Weber, Griffin M; Hill, Emorcia V; Reede, Joan Y

    2016-01-01

    Business literature has demonstrated the importance of networking and connections in career advancement. This is a little-studied area in academic medicine. To examine predictors of intra-organizational connections, as measured by network reach (the number of first- and second-degree coauthors), and their association with probability of promotion and attrition. Prospective cohort study between 2008 and 2012. Academic medical center. A total of 5787 Harvard Medical School (HMS) faculty with a rank of assistant professor or full-time instructor as of January 1, 2008. Using negative binomial models, multivariable-adjusted predictors of continuous network reach were assessed according to rank. Poisson regression was used to compute relative risk (RR) and 95 % confidence intervals (CI) for the association between network reach (in four categories) and two outcomes: promotion or attrition. Models were adjusted for demographic, professional and productivity metrics. Network reach was positively associated with number of first-, last- and middle-author publications and h-index. Among assistant professors, men and whites had greater network reach than women and underrepresented minorities (p advancement and retention in academic medicine. They can and should be investigated at other institutions.

  3. Taking into account the impact of attrition on the assessment of response shift and true change: a multigroup structural equation modeling approach

    NARCIS (Netherlands)

    Verdam, M.G.E.; Oort, F.J.; van der Linden, Y.M.; Sprangers, M.A.G.

    2015-01-01

    Purpose: Missing data due to attrition present a challenge for the assessment and interpretation of change and response shift in HRQL outcomes. The objective was to handle such missingness and to assess response shift and ‘true change’ with the use of an attrition-based multigroup structural

  4. Taking into account the impact of attrition on the assessment of response shift and true change: a multigroup structural equation modeling approach

    NARCIS (Netherlands)

    Verdam, Mathilde G. E.; Oort, Frans J.; van der Linden, Yvette M.; Sprangers, Mirjam A. G.

    2015-01-01

    Missing data due to attrition present a challenge for the assessment and interpretation of change and response shift in HRQL outcomes. The objective was to handle such missingness and to assess response shift and 'true change' with the use of an attrition-based multigroup structural equation

  5. Attrition of Dolomitic Lime in a Fluidized-Bed at High Temperature

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Svoboda, Karel; Pohořelý, Michael; Šyc, Michal; Jeremiáš, Michal

    2013-01-01

    Roč. 67, č. 2 (2013), s. 164-172 ISSN 0366-6352 R&D Projects: GA AV ČR IAA400720701; GA MŠk(CZ) 7C11009 Grant - others:RFCS(XE) RFCR-CT-2010-00009 Institutional support: RVO:67985858 Keywords : attrition * catalytic gasification * dolomitic lime Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.193, year: 2013

  6. The role of service readiness and health care facility factors in attrition from Option B+ in Haiti: a joint examination of electronic medical records and service provision assessment survey data.

    Science.gov (United States)

    Lipira, Lauren; Kemp, Christopher; Domercant, Jean Wysler; Honoré, Jean Guy; Francois, Kesner; Puttkammer, Nancy

    2018-01-01

    Option B+ is a strategy wherein pregnant or breastfeeding women with HIV are enrolled in lifelong antiretroviral therapy (ART) for prevention of mother-to-child transmission (PMTCT) of HIV. In Haiti, attrition from Option B+ is problematic and variable across health care facilities. This study explores service readiness and other facility factors as predictors of Option B+ attrition in Haiti. This analysis used longitudinal data from 2012 to 2014 from the iSanté electronic medical record system and cross-sectional data from Haiti's 2013 Service Provision Assessment. Predictors included Service Availability and Readiness Assessment (SARA) measures for antenatal care (ANC), PMTCT, HIV care services and ART services; general facility characteristics and patient-level factors. Multivariable Cox proportional hazards models modelled the time to first attrition. Analysis of data from 3147 women at 63 health care facilities showed no significant relationships between SARA measures and attrition. Having integrated ANC/PMTCT care and HIV-related training were significant protective factors. Being a public-sector facility, having a greater number of quality improvement activities and training in ANC were significant risk factors. Several facility-level factors were associated with Option B+ attrition. Future research is needed to explore unmeasured facility factors, clarify causal relationships, and incorporate community-level factors into the analysis of Option B+ attrition. © The Author(s) 2018. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Taking into account the impact of attrition on the assessment of response shift and true change: a multigroup structural equation modeling approach.

    Science.gov (United States)

    Verdam, Mathilde G E; Oort, Frans J; van der Linden, Yvette M; Sprangers, Mirjam A G

    2015-03-01

    Missing data due to attrition present a challenge for the assessment and interpretation of change and response shift in HRQL outcomes. The objective was to handle such missingness and to assess response shift and 'true change' with the use of an attrition-based multigroup structural equation modeling (SEM) approach. Functional limitations and health impairments were measured in 1,157 cancer patients, who were treated with palliative radiotherapy for painful bone metastases, before [time (T) 0], every week after treatment (T1 through T12), and then monthly for up to 2 years (T13 through T24). To handle missing data due to attrition, the SEM procedure was extended to a multigroup approach, in which we distinguished three groups: short survival (3-5 measurements), medium survival (6-12 measurements), and long survival (>12 measurements). Attrition after third, sixth, and 13th measurement occasions was 11, 24, and 41 %, respectively. Results show that patterns of change in functional limitations and health impairments differ between patients with short, medium, or long survival. Moreover, three response-shift effects were detected: recalibration of 'pain' and 'sickness' and reprioritization of 'physical functioning.' If response-shift effects would not have been taken into account, functional limitations and health impairments would generally be underestimated across measurements. The multigroup SEM approach enables the analysis of data from patients with different patterns of missing data due to attrition. This approach does not only allow for detection of response shift and assessment of true change across measurements, but also allow for detection of differences in response shift and true change across groups of patients with different attrition rates.

  8. Germanic heritage languages in North America: Acquisition, attrition and change

    OpenAIRE

    Johannessen, Janne Bondi; Salmons, Joseph C.; Westergaard, Marit; Anderssen, Merete; Arnbjörnsdóttir, Birna; Allen, Brent; Pierce, Marc; Boas, Hans C.; Roesch, Karen; Brown, Joshua R.; Putnam, Michael; Åfarli, Tor A.; Newman, Zelda Kahan; Annear, Lucas; Speth, Kristin

    2015-01-01

    This book presents new empirical findings about Germanic heritage varieties spoken in North America: Dutch, German, Pennsylvania Dutch, Icelandic, Norwegian, Swedish, West Frisian and Yiddish, and varieties of English spoken both by heritage speakers and in communities after language shift. The volume focuses on three critical issues underlying the notion of ‘heritage language’: acquisition, attrition and change. The book offers theoretically-informed discussions of heritage language processe...

  9. Analysis of Recruit Attrition from the Navy's Delayed Entry Program and Recruit Training Command

    National Research Council Canada - National Science Library

    Neuhalfen, Jon K

    2007-01-01

    .... The analysis uses the PRIDE database, provided by Commander, Navy Recruiting Command. Trend analyses are used to identify significant changes in enlistment and attrition behavior for recruits who joined from fiscal years 1998 through 2005...

  10. The Flip Side of the Attrition Coin: Faculty Perceptions of Factors Supporting Graduate Student Success

    Directory of Open Access Journals (Sweden)

    Joanna A Gilmore

    2016-12-01

    Full Text Available Doctoral attrition consistently hovers around 50% with relevant literature identifying several mediating factors, including departmental culture, student demographics, and funding. To advance this literature, we interviewed 38 graduate faculty advisors in science, engineering, or mathematics disciplines at a research-extensive university to capture their perceptions of factors supporting graduate student success. Using a constant-comparison method, we found that faculty perceptions aligned within three major categories, termed: motivated student behaviors, formative student learning experiences, and essential student knowledge and skills. Student motivation was most prominently represented in findings. This aligns with prior studies showing that faculty tend to identify the cause of graduate student failure as lying within the students themselves and rarely discuss their role or the department’s contribution to attrition. Thus findings offer an opportunity to reflect and improve upon practice. The study also highlights actions graduate students can take to increase success, such as developing collegial relationships and early involvement in research and scholarly writing. We encourage graduate faculty advisors and others to identify ways to help graduate students overcome common obstacles to enduring and succeeding within graduate programs. Faculty perceptions are also examined by discipline and faculty rank, and directions for future research are offered.

  11. A Selective Mutism Arising from First Language Attrition, Successfully Treated with Paroxetine-CBT Combination Treatment.

    Science.gov (United States)

    Serra, Agostino; Di Mauro, Paola; Andaloro, Claudio; Maiolino, Luigi; Pavone, Piero; Cocuzza, Salvatore

    2015-10-01

    After immersion in a foreign language, speakers often have difficulty retrieving native-language words and may experience a decrease in its proficiency, this phenomenon, in the non-pathological form, is known as first language attrition. Self-perception of this low native-language proficiency and apprehension occurring when speaking is expected and, may sometimes lead these people to a state of social anxiety and, in extreme forms, can involve the withholding of speech as a primitive tool for self-protection, linking them to selective mutism. We report an unusual case of selective mutism arising from first language attrition in an Italian girl after attending a two-year "German language school", who successfully responded to a paroxetine-cognitive behavioral treatment (CBT) combination treatment.

  12. Experimental investigation of attrition resistance of zeolite catalysts in two particle gas-solid-solid fluidization system

    International Nuclear Information System (INIS)

    Nawaz, Z.; Ziaoping, T.; Shu, Q.; Wei, F.; Naveed, S.

    2010-01-01

    In the study of mechanical degradation of 34 ZSM-5 and SAPO catalysts, using the gas jet attrition - ASTM standard fluidized bed test (D-5757), the effect of particle size and its quantitative analysis in co-fluidization environment was investigated on the air jet index (AJI) basis. In gas-solid-solid fluidized bed reactors (GSS-FBR), two different sized particles were fluidized under isothermal conditions. In case of ZSM-5 and SAPO-34, significant attrition resistance was observed, which was attributed to small pore size and specific structural strength of the mobile framework image (MFI) and chabasite (CHA) structures, respectively. The optimum AJI for SAPO-34 and ZSM-5 (of particle size 0.2 mm) in GSS-fluidization system was observed to be 0.0118 and 0.0062, respectively. In co-fluidization, deviations from Gwyn relationship were observed due to change in impact of collision. Therefore, zeolites are recommended as suitable catalysts or catalytic supports (for doping of expensive metals) and for commercial use in GSS-FBR. (author)

  13. Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis

    Science.gov (United States)

    2015-03-26

    Further complicating human resourcing, all Air Force members–enlisted and officer–start at entry-level. Personnel entering the Air Force inventory are...the system [8]. Chi-squared automatic interaction detection (CHAID) is an algorithm “to predict the response behaviour [sic] of individuals as...branches with the highest probability may require incentives to increase attrition. The branches could be defined by gender, career field, religion

  14. Influence of attrition scrubbing, ultrasonic treatment, and oxidant additions on uranium removal from contaminated soils

    International Nuclear Information System (INIS)

    Timpson, M.E.; Elless, M.P.; Francis, C.W.

    1994-01-01

    As part of the Uranium in Soils Integrated Demonstration Project being conducted by the US Department of Energy, bench-scale investigations of selective leaching of uranium from soils at the Fernald Environmental Management Project site in Ohio were conducted at Oak Ridge National Laboratory. Two soils (storage pad soil and incinerator soil), representing the major contaminant sources at the site, were extracted using carbonate- and citric acid-based lixiviants. Physical and chemical processes were used in combination with the two extractants to increase the rate of uranium release from these soils. Attrition scrubbing and ultrasonic dispersion were the two physical processes utilized. Potassium permanganate was used as an oxidizing agent to transform tetravalent uranium to the hexavalent state. Hexavalent uranium is easily complexed in solution by the carbonate radical. Attrition scrubbing increased the rate of uranium release from both soils when compared with rotary shaking. At equivalent extraction times and solids loadings, however, attrition scrubbing proved effective only on the incinerator soil. Ultrasonic treatments on the incinerator soil removed 71% of the uranium contamination in a single extraction. Multiple extractions of the same sample removed up to 90% of the uranium. Additions of potassium permanganate to the carbonate extractant resulted in significant changes in the extractability of uranium from the incinerator soil but had no effect on the storage pad soil

  15. Inter-disciplinary management of a patient with severely attrited teeth

    Directory of Open Access Journals (Sweden)

    Padmanabhan Shyam

    2010-01-01

    Full Text Available With increased awareness about dental esthetics, multidisciplinary periodontal therapy has begun to gain momentum. Management of severely attrited teeth is a challenging situation and is dealt with a multidisciplinary approach. In cases of severe tooth wear, the crown height is drastically reduced, in some cases up to the gingival level. This might require a contribution from the disciplines of endodontics, periodontics, orthodontics and prosthodontics for predictable results. Herein we describe the management of one such case.

  16. Articulating attrition: Graduate school experiences of female doctoral students in the sciences

    Science.gov (United States)

    Osburn, Kathryn Ann

    2005-07-01

    Despite decades of research and reform efforts designed to bolster female retention in scientific disciplines, the conundrum of women's departure from doctoral programs in the sciences remains. This qualitative case study investigated the aspects of the graduate school experience that female doctoral students described as facilitating or impeding their successful degree completion in chemistry. I analyzed the graduate school narratives of twelve female participants who represented both successful and unsuccessful doctoral recipients from four advisors at one university. Participants identified four types of experiences that facilitated their retention in the doctoral program: feeling successful and confident in meeting the program requirements, having positive research experiences, receiving support from social networks, and being dedicated to career goals. Participants cited four kinds of experiences that impeded their continued participation in the doctoral program: having negative research experiences, feeling a lack of success and confidence in meeting the program requirements, changing career goals, and receiving no support from social networks. The graduate school experiences of participants who did and did not successfully attain their degree objectives differed in terms of four dimensions: pre-program experiences, academic experiences, advisory experiences, and social experiences. Based on these findings, I have proposed a model of attrition and retention that emphasizes the role that these unique program experiences play in shaping participants' sense of professional fit within the community of doctoral chemists, consequently contributing to their differential program outcomes. This study not only offers a new perspective on the phenomenon of female doctoral attrition in the sciences but also informs the development of more gender-inclusive graduate science practices and policies that will support the retention of female doctoral students.

  17. Interpreting trial results following use of different intention-to-treat approaches for preventing attrition bias: a meta-epidemiological study protocol

    OpenAIRE

    Dossing, Anna; Tarp, Simon; Furst, Daniel E; Gluud, Christian; Beyene, Joseph; Hansen, Bjarke B; Bliddal, Henning; Christensen, Robin

    2014-01-01

    Introduction When participants drop out of randomised clinical trials, as frequently happens, the intention-to-treat (ITT) principle does not apply, potentially leading to attrition bias. Data lost from patient dropout/lack of follow-up are statistically addressed by imputing, a procedure prone to bias. Deviations from the original definition of ITT are referred to as modified intention-to-treat (mITT). As yet, the impact of the potential bias associated with mITT has not been assessed. Our o...

  18. Peroneus Brevis Attrition & Longitudinal Split Tear without Subluxation and Associated Hypertrophy of Peronal Tubercle" - Treatment of an Uncommon Lesion.

    Science.gov (United States)

    Tiwari, Mukesh; Singh, Varun; Bhargava, Rakesh

    2015-01-01

    Peroneus brevis tendinitis with its attritional longitudinal split rupture without any subluxation from peroneal groove and associated enlarged peroneal tubercle is un common presentation. A 40 year old female presented with moderate swelling and tenderness over the lateral and dorso-lateral aspect of left ankle with history of old trauma to ankle with swelling, persistant pain and difficulty in walking. On physical examination during passive eversion and inversion the excursion of the peroneal tendons was painful. Most tender point was just posterior to the tip of the fibula. During surgery we found the intact superior peroneal ligament with both peroneal tendons placed at normal site without subluxation, tendon sheath was inflamed and swollen, on further dissection we could see the attrition of inner surface of the peroneus brevis and a 2 cm longitudinal split tear of the same. Although rare but peroneus brevis tendon attrition and tear can occur without subluxation from peronal groove. Refractory ankle pain on lateral aspect presenting with on and off swelling should arise suspicion of peroneal tendon tear. Correct diagnosis and proper surgical repair can produce excellent results.

  19. The Role of Social Support in First-Term Sailors’ Attrition from Recruit Training

    Science.gov (United States)

    2008-04-01

    absenteeism , and job turnover during the first year of employment. Academy of Management Journal, 28, 88-109. Shils, E. A. & Janowitz, M. (1948). Cohesion and...British Army. Journal of Organizational Behavior, 19, 745-767. Tinto, V. (1993). Leaving college: Rethinking the causes and cures of student attrition

  20. Career Stories of Israeli Teachers Who Left Teaching: A Salutogenic View of Teacher Attrition

    Science.gov (United States)

    Yinon, Hayuta; Orland-Barak, Lily

    2017-01-01

    Many countries experience a high percentage of teachers who leave the profession before retirement. Most of the explanations, such as teacher burnout, adopt a pathogenic point of view which perceives attrition as a negative work outcome. In contrast, the qualitative project that this article is based on, which characterizes the career…

  1. The Effect of Household and Community on School Attrition: An Analysis of Thai Youth

    Science.gov (United States)

    Korinek, Kim; Punpuing, Sureeporn

    2012-01-01

    We analyze school attrition among youth in Kanchanaburi province, Thailand. We find that family investments in schooling are shaped by both household and local community contexts. There is an enrollment advantage for girls across different households and communities. We find that youth whose mothers have migrated and youth in immigrant households…

  2. Application of a Duration Model in Programs for Prevention of University Attrition

    Directory of Open Access Journals (Sweden)

    Verónica Herrero

    2013-12-01

    Full Text Available Institutional practices related to the prevention of desertion of university students increasingly require validated instruments in order to anticipate such behavior. In this regard, different statistical models generated from information related to the students themselves, their homes, their academic performance, among other determinants have demonstrated to be of crucial value. This study aims to demonstrate the importance of a series of determinants explored in other studies. The main objective is to apply a dropout rate predictive model with at risk university students in order to generate early and progressively more effective results. The research demonstrates the usefulness of the duration models in a sample of classroom students and the capacity to anticipate behavior of permanence/attrition across time. This was done with risk estimates using the Cox model.

  3. Attrition, elutriation, and growth of particles produced in fluidized-bed waste calciners

    International Nuclear Information System (INIS)

    McDonald, F.N.

    1982-09-01

    The Idaho Chemical Processing Plant reduces the volume of high-level liquid radioactive wastes in a fluidized bed to produce a granular calcine product. In the past, difficulties have been experienced in controlling the product's particle size when processing certain blends of sodium-bearing waste. Therefore, experiments in attrition, elutriation, and particle growth were done to characterize how best to control these three parameters. 15 figures, 16 tables

  4. Relationship between Measures of Academic Quality and Undergraduate Student Attrition: The Case of Higher Education Institutions in the Colombian Caribbean Region

    Science.gov (United States)

    Martínez, Anabella; Borjas, Mónica; Herrera, Mariela; Valencia, Jorge

    2015-01-01

    Undergraduate student attrition is a major concern in higher education. It is usually explained by the impact of student attributes; however, recent developments in student success literature point to the need of exploring institutional practices that may impact a student's decision to abandon their studies. The current weight of academic quality…

  5. A review of trends in attrition rates for surgical faculty: a case for a sustainable retention strategy to cope with demographic and economic realities.

    Science.gov (United States)

    Satiani, Bhagwan; Williams, Thomas E; Brod, Heather; Way, David P; Ellison, E Christopher

    2013-05-01

    Our aim was to compare trends in retention of academic surgeons by reviewing surgical faculty attrition rates (leaving academic surgery for any reason) of 3 cohorts at 5-year intervals between 1996 and 2011. The Association of American Medical Colleges' Faculty Administrative Management On-Line User System database was queried for a retention report of all tenure/clinical track full-time MD faculty within our academic medical center on July 1, 1996 (group 1), July 1, 2001 (group 2), and July 1, 2006 (group 3). Retention was tracked for 5 years post snapshot. The individual 5-year cohort attrition rates (observed frequencies) were compared with combined attrition rates for all 3 groups (expected frequencies). Overall, attrition trends for groups 2 (lower) and 3 (higher) were significantly different than the trends for all groups combined. Minorities and professors at the full or associate rank in group 3 contributed to this difference. Faculty in group 3 leaving our academic medical center were significantly more likely to transition into nonacademic practice compared with the other 2 groups. Greater attrition in the last 5-year cohort, despite the increase in faculty positions, is worrisome. A continuous retention life cycle is critical if academic medical centers hope to compete for talent. Retention planning should include on-boarding programs for enculturation, monitoring of professional satisfaction, formalized mentoring of younger surgeons, retaining academic couples and a part-time workforce, leadership and talent management, exit interviews, and competitive financial packages. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  6. The Dissertation Story: What Is the Relationship between the Officer Candidate School Attrition Rate and Officer Training Command, Naval Service Training Command and Navy Recruiting Command Leadership Intervention?

    Science.gov (United States)

    2013-03-01

    attrition (Goodstadt, 1981). Kubisiak, et al. contend that leaders should consider attrition a negative occurrence and that each leader should develop...related to the information, and the consequences associated with the options. The ability to ruminate before acting when presented with new information or

  7. A Strategy of Attrition through Enforcement: The Unmaking of Irregular Migration in Malaysia

    OpenAIRE

    Choo Chin Low

    2017-01-01

    This article reviews Malaysia's attempt to achieve zero migration irregularity by focusing on workplace enforcement, and examines how Malaysia's migration control has become a struggle between the state and employers. Applying the framework of "enforcement through attrition", this research examines three newly introduced principles governing workplace enforcement: employer sanctions, the Strict Liability Principle, and the Employers' Mandatory Commitment. The shift to employers in Malaysia's ...

  8. Special Education Teacher Perception of Administrative Supports That Encourage, Decrease Burnout, and Reduce Attrition

    Science.gov (United States)

    Beebe, Jay

    2017-01-01

    The field of special education is facing a shortage of teachers. A shortage of special education teachers is an example of a pressing issue within education. The problem is that teacher attrition rates are among the highest within special education. Many special education teachers are leaving the profession after a few years of teaching for varied…

  9. Analysis of Civilian Employee Attrition at the Naval Postgraduate School and Naval Support Activity - Monterey Bay

    National Research Council Canada - National Science Library

    Valverde, Xavier

    1997-01-01

    ...) and Naval Support Activity-Monterey Bay (NSA-MB) to determine what civilian non-faculty employee jobs are likely to be left vacant in the next three years due to attrition and to identify what training and skills will be needed by personnel whose...

  10. Migration as a form of workforce attrition: a nine-country study of pharmacists.

    Science.gov (United States)

    Wuliji, Tana; Carter, Sarah; Bates, Ian

    2009-04-09

    There is a lack of evidence to inform policy development on the reasons why health professionals migrate. Few studies have sought to empirically determine factors influencing the intention to migrate and none have explored the relationship between factors. This paper reports on the first international attempt to investigate the migration intentions of pharmacy students and identify migration factors and their relationships. Responses were gathered from 791 final-year pharmacy students from nine countries: Australia, Bangladesh, Croatia, Egypt, Portugal, Nepal, Singapore, Slovenia and Zimbabwe. Data were analysed by means of Principal Components Analysis (PCA) and two-step cluster analysis to determine the relationships between factors influencing migration and the characteristics of subpopulations most likely and least likely to migrate. Results showed a significant difference in attitudes towards the professional and sociopolitical environment of the home country and perceptions of opportunities abroad between those who have no intention of migrating and those who intend to migrate on a long-term basis. Attitudes of students planning short-term migration were not significantly different from those of students who did not intend to migrate. These attitudes, together with gender, knowledge of other migrant pharmacists and past experiences abroad, are associated with an increased propensity for migration. Given the influence of the country context and environment on migration intentions, research and policy should frame the issue of migration in the context of the wider human resource agenda, thus viewing migration as one form of attrition and a symptom of other root causes. Remuneration is not an independent stand-alone factor influencing migration intentions and cannot be decoupled from professional development factors. Comprehensive human resource policy development that takes into account the issues of both remuneration and professional development are necessary

  11. I Ain't Gonna Make It. Comparing Job Demands-Resources and Attrition Intention Between Senior Teachers and Senior Employees of Six Other Occupational Categories in Flanders.

    Science.gov (United States)

    Van Droogenbroeck, Filip; Spruyt, Bram

    2016-07-01

    Teachers are often thought to retire early and have more stress and burnout than other human service professionals. In this article, we investigate attrition intention amongst senior teachers and senior employees of six other blue- and white-collar occupational categories using the Job Demands-Resources (JD-R) model. We followed a two-step approach. First, analysis of variance and logistic regression analysis was used to assess differences in the level of job demands, resources, and attrition intention between occupations for male and female employees separately. Subsequently, multiple group path analysis was used to assess the invariance of the JD-R model across occupational groups and genders. We used representative data gathered in Flanders among 6,810 senior employees (45 years or older). Results indicate that there are differences in the determinants of attrition intention between men and women. The differences in attrition intention are minimal between occupations once controlled for job demands and resources. In addition, the JD-R model is largely invariant across white-collar occupations and gender. We provide support for both the energetic and motivational process of the JD-R model. © The Author(s) 2016.

  12. Developing a national computerised absence monitoring and management system to reduce nursing student attrition: evaluation of staff and student perspectives.

    Science.gov (United States)

    Currie, Kay; McCallum, Jacqueline; Murray, John; Scott, Janine; Strachan, Evelyn; Yates, Lynda; Wright, Marty

    2014-05-01

    Reducing avoidable nursing student attrition is an international challenge. A pattern of falling attendance is recognised as a frequent precursor to withdrawal from nursing programmes. To address concerns regarding nursing student attrition, the Scottish Government implemented a pilot project for a centralised Computerised Absence Management and Monitoring System (CAMMS). The CAMMS adopted an 'assertive outreach' approach, contacting students every two weeks via colour coded letters to tell them whether their attendance was 'excellent', 'good, but potentially causing concern'; or 'warning; attendance concerns/contact academic staff for support'. This article reports key findings from an evaluation of CAMMS. To explore the perceived impact of CAMMS on student support and attrition, from the perspectives of academic and administrative staff and students. Mixed methods evaluation design. Three large geographically dispersed Schools of Nursing in Scotland. 83 students; 20 academic staff; and 3 lead administrators. On-line cohort survey of academic staff and students; structured interviews with lead administrators. Findings reflected a spectrum of negative and positive views of CAMMS. Students who are attending regularly seem pleased that their commitment is recognised. Lecturers who teach larger groups report greater difficulty getting to know students individually and acknowledge the benefit of identifying potential attendance concerns at an early stage. Conversely, some students who received a 'warning' letter were frequently annoyed or irritated, rather than feeling supported. Increased staff workload resulted in negative perceptions and a consequent reluctance to use CAMMS. However, students who were causing concern reported subsequent improvement in attendance. CAMMS has the potential to identify 'at-risk' students at an early stage; however, the system should have flexibility to tailor automatically generated letters in response to individual circumstances, to

  13. Nanostructuring of Aluminum Alloy Powders by Cryogenic Attrition with Hydrogen-Free Process Control Agent

    Science.gov (United States)

    2015-02-01

    Nanostructuring of Aluminum Alloy Powders by Cryogenic Attrition with Hydrogen-Free Process Control Agent by Frank Kellogg , Clara Hofmeister...Process Control Agent Frank Kellogg Bowhead Science and Technology Clara Hofmeister Advanced Materials Processing and Analysis Center...NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Frank Kellogg , Clara Hofmeister, Anit Giri, and Kyu Cho 5d. PROJECT NUMBER 5e

  14. Exercise Intervention: Attrition, Compliance, Adherence, and Progression Following Hematopoietic Stem Cell Transplantation
.

    Science.gov (United States)

    Peters, Tara; Erdmann, Ruby; Hacker, Eileen Danaher

    2018-02-01

    Exercise is widely touted as an effective intervention to optimize health and well-being after high-dose chemotherapy and hematopoietic stem cell transplantation. 
. This article reports attrition, compliance, adherence, and progression from the strength training arm of the single-blind randomized, controlled trial Strength Training to Enhance Early Recovery (STEER). 
. 37 patients were randomized to the intervention and participated in a structured strength training program introduced during hospitalization and continued for six weeks after release. Research staff and patients maintained exercise logs to document compliance, adherence, and progression. 
. No patients left the study because of burden. Patients were compliant with completion of exercise sessions, and their adherence was high; they also progressed on their exercise prescription. Because STEER balances intervention effectiveness with patient burden, the findings support the likelihood of successful translation into clinical practice.

  15. Disappearing Act: Persistence and Attrition of Uniform Resource Locators (URLs) in an Open Access Medical Journal

    Science.gov (United States)

    Nagaraja, Aragudige; Joseph, Shine A.; Polen, Hyla H.; Clauson, Kevin A.

    2011-01-01

    Purpose: The aim of this paper is to assess and catalogue the magnitude of URL attrition in a high-impact, open access (OA) general medical journal. Design/methodology/approach: All "Public Library of Science Medicine (PLoS Medicine)" articles for 2005-2007 were evaluated and the following items were assessed: number of entries per issue; type of…

  16. Gender-related differences in outcomes and attrition on antiretroviral treatment among an HIV-infected patient cohort in Zimbabwe: 2007–2010

    Directory of Open Access Journals (Sweden)

    Kudakwashe C. Takarinda

    2015-01-01

    Conclusions: Our findings show that males presented late for ART initiation compared to females. Similar to other studies, males had higher patient attrition and mortality compared to females and this may be attributed in part to late presentation for HIV treatment and care. These observations highlight the need to encourage early HIV testing and enrolment into HIV treatment and care, and eventually patient retention on ART, particularly amongst men.

  17. Should I Stay or Should I Go? Factors that Influence the Retention, Turnover, and Attrition of K-12 Music Teachers in the United States

    Science.gov (United States)

    Gardner, Robert D.

    2010-01-01

    The purpose of this study was to construct a profile of K-12 music teachers in the United States and develop a model to predict their retention, turnover, and attrition. Responses to the "Schools and Staffing Survey" from 47,857 K-12 public and private school teachers, including 1,903 music teachers, were analyzed using comparative…

  18. Production of fines during co-combustion of coal with biomass fuels by fragmentation and attrition

    Energy Technology Data Exchange (ETDEWEB)

    I. Gulyurtlu; D. Boavida; H. Lopes (and others) [DEECA-INETI, Lisbon (Portugal)

    2005-07-01

    Results are reported from a project funded by the RFCS Programme of the European Union. The aim is to investigate, experimentally and by modeling, the production of fine char and ash particles during co-combustion of coal with wastes and biofuels in circulating fluidized bed. Work was undertaken at installations of different scales. Polish and Colombian coals were base fuels. The additional fuels were two sewage sludges. Bed temperature, feeding system, sand particle size, devolatilisation behaviour and char burn-out were studied to verify their influence on the fine particle production. Modeling was also carried out to understand the mechanisms of fragmentation and attrition. Samples from bed and cyclone were collected to determine particle size distributions. 11 refs.

  19. The Impact of Junior Reserve Officer Training Corps and Other Youth Programs on Navy First-Term Attrition, Promotion, and Reenlistment

    National Research Council Canada - National Science Library

    Lamont, Roy A

    2007-01-01

    ...) and other youth programs significantly affects the performance of first-term Navy enlistees. This analysis makes use of multivariate models to estimate the causal effect of JROTC participation on first-term attrition, promotion and reenlistment...

  20. Tone Attrition in Mandarin Speakers of Varying English Proficiency

    Science.gov (United States)

    Creel, Sarah C.

    2017-01-01

    Purpose The purpose of this study was to determine whether the degree of dominance of Mandarin–English bilinguals' languages affects phonetic processing of tone content in their native language, Mandarin. Method We tested 72 Mandarin–English bilingual college students with a range of language-dominance profiles in the 2 languages and ages of acquisition of English. Participants viewed 2 photographs at a time while hearing a familiar Mandarin word referring to 1 photograph. The names of the 2 photographs diverged in tone, vowels, or both. Word recognition was evaluated using clicking accuracy, reaction times, and an online recognition measure (gaze) and was compared in the 3 conditions. Results Relative proficiency in English was correlated with reduced word recognition success in tone-disambiguated trials, but not in vowel-disambiguated trials, across all 3 dependent measures. This selective attrition for tone content emerged even though all bilinguals had learned Mandarin from birth. Lengthy experience with English thus weakened tone use. Conclusions This finding has implications for the question of the extent to which bilinguals' 2 phonetic systems interact. It suggests that bilinguals may not process pitch information language-specifically and that processing strategies from the dominant language may affect phonetic processing in the nondominant language—even when the latter was learned natively. PMID:28124064

  1. Patient retention, clinical outcomes and attrition-associated factors of HIV-infected patients enrolled in Zimbabwe's National Antiretroviral Therapy Programme, 2007-2010.

    Directory of Open Access Journals (Sweden)

    Tsitsi Mutasa-Apollo

    Full Text Available Since establishment of Zimbabwe's National Antiretroviral Therapy (ART Programme in 2004, ART provision has expanded from <5,000 to 369,431 adults by 2011. However, patient outcomes are unexplored.To determine improvement in health status, retention and factors associated with attrition among HIV-infected patients on ART.A retrospective review of abstracted patient records of adults ≥ 15 years who initiated ART from 2007 to 2009 was done. Frequencies and medians were calculated for rates of retention in care and changes in key health status outcomes at 6, 12, 24 and 36 months respectively. Cox proportional hazards models were used to determine factors associated with attrition.Of the 3,919 patients, 64% were female, 86% were either WHO clinical stage III or IV. Rates of patient retention at 6, 12, 24 and 36 months were 90.7%, 78.1%, 68.8% and 64.4%, respectively. After ART initiation, median weight gains at 6, 12, and 24 months were 3, 4.5, and 5.0 kgs whilst median CD4+ cell count gains at 6, 12 and 24 months were 122, 157 and 279 cells/µL respectively. Factors associated with an increased risk of attrition included male gender (AHR 1.2; 95% CI, 1.1-1.4, baseline WHO stage IV (AHR 1.7; 95% CI, 1.1-2.6, lower baseline body weight (AHR 2.0; 95% CI, 1.4-2. 8 and accessing care from higher level healthcare facilities (AHR 3.5; 95% 1.1-11.2.Our findings with regard to retention as well as clinical and immunological improvements following uptake of ART, are similar to what has been found in other settings. Factors influencing attrition also mirror those found in other parts of sub-Saharan Africa. These findings suggest the need to strengthen earlier diagnosis and treatment to further improve treatment outcomes. Whilst decentralisation improves ART coverage it should be coupled with strategies aimed at improving patient retention.

  2. CU-STARs: Promoting STEM Diversity by Addressing First-year Attrition of Underrepresented Minorities

    Science.gov (United States)

    Battersby, Cara; Silvia, Devin W.; Ellingson, Erica; Sturner, Andrew P.; Peck, Courtney

    2015-01-01

    Upon first entering university, the fraction of students interested in pursuing a STEM major are distributed according to societal demographics (with 25% being underrepresented minorities), but by graduation, the fraction of students receiving STEM degrees is unbalanced, with underrepresented minorities receiving only 15% of STEM bachelor's degrees. The CU-STARs (CU Science, Technology, and Astronomy Recruits) program at the University of Colorado, Boulder is targeted to address the main triggers of early career attrition for underrepresented minorities in STEM disciplines. A select group of students are given financial support through work-study at the Fiske planetarium on campus, while resources to address other triggers of attrition are available to the entire cohort of interested students (typically ~5-10 per year). These resources are designed to promote social engagement and mentorship, while also providing a support network and resources to combat inadequate high school preparation for STEM courses. We achieve these goals through activities that include social events, mentor meetings, free tutoring, and special events to meet and talk with scientists. The culmination of the program for the recruits are a series of high school outreach events in underserved areas (inner city and rural alike), in which they become the expert. The STARs are paid for their time and take the lead in planning, teaching, and facilitating programs for the high school students, including classroom presentations, interactive lab activities, solar observing, and star parties. The high school outreach events provide role models and STEM exposure for the underserved high school community while simultaneously cementing the personal achievements and successes for the STARs. CU-STARs is now in its 4th year and is still growing. We are beginning the process of formal assessments of the program's success. We present details of the program implementation, a discussion of potential obstacles

  3. Interpreting trial results following use of different intention-to-treat approaches for preventing attrition bias: a meta-epidemiological study protocol.

    Science.gov (United States)

    Dossing, Anna; Tarp, Simon; Furst, Daniel E; Gluud, Christian; Beyene, Joseph; Hansen, Bjarke B; Bliddal, Henning; Christensen, Robin

    2014-09-26

    When participants drop out of randomised clinical trials, as frequently happens, the intention-to-treat (ITT) principle does not apply, potentially leading to attrition bias. Data lost from patient dropout/lack of follow-up are statistically addressed by imputing, a procedure prone to bias. Deviations from the original definition of ITT are referred to as modified intention-to-treat (mITT). As yet, the impact of the potential bias associated with mITT has not been assessed. Our objective is to investigate potential bias and disadvantages of performing mITT and evaluate possible concerns when executing different mITT approaches in meta-analyses. Using meta-epidemiology on randomised trials considered less prone to bias (ie, good internal validity) and assessing biological or targeted agents in patients with rheumatoid arthritis, we will meta-analyse data from 10 biological and targeted drugs based on collections of trials that would correspond to 10 individual meta-analyses. This study will enhance transparency for evaluating mITT treatment effects described in meta-analyses. The intended audience will include healthcare researchers, policymakers and clinicians. Results of the study will be disseminated by peer-review publication. In PROSPERO CRD42013006702, 11. December 2013. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Predicting Active Duty Air Force Pilot Attrition Given an Anticipated Increase in Major Airline Pilot Hiring

    Science.gov (United States)

    2015-01-01

    the Air Force in addressing some quality-of-life issues, such as updating 3,800 family housing units, 21 dormitories, and building three child ...of pilots into the airlines (Air Force Personnel Center, FY 07). By allowing this crop of pilots to leave on the Air Force’s terms, the service felt...attrition rates compared with pilots with more general skills (flying mobility aircraft) (Stephen P. Barrows, 1993). This may be due to the phenomenon in

  5. An electromyographic study to assess the minimal time duration for using the splint to raise the vertical dimension in patients with generalized attrition of teeth

    Directory of Open Access Journals (Sweden)

    Aditi Nanda

    2011-01-01

    Full Text Available Background: To investigate the effect of restoration of lost vertical by centric stabilizing splint on electromyographic (EMG activity of masseter and anterior temporalis muscles bilaterally in patients with generalized attrition of teeth. Materials and Methods: EMG activity of anterior temporalis and masseter muscle was recorded bilaterally for 10 patients whose vertical was restored with centric stabilizing splint. The recording was done at postural rest position and in maximum voluntary clenching for each subject before the start of treatment, immediately after placement of splint and at subsequent recall visits, with splint and without the splint. Results: The EMG activity at postural rest position (PRP and maximum voluntary clench (MVC decreased till 1 month for both the muscles. In the third month, an increase in muscle activity toward normalization was noted at PRP, both with and without splint. At MVC in the third month, the muscle activity without splint decreased significantly as compared to pretreatment values for anterior temporalis and masseter, while with the splint an increase was seen beyond the pretreatment values. Conclusion: A definite response of anterior temporalis and masseter muscle was observed over a period of 3 months. This is suggestive that the reversible increase in vertical prior to irreversible intervention must be carried out for a minimum of 3 months to achieve neuromuscular deprogramming. This allows the muscle to get adapted to the new postural position and attain stability in occlusion following splint therapy.

  6. Adolescent and Young Adult Patient Engagement and Participation in Survey-Based Research: A Report From the "Resilience in Adolescents and Young Adults With Cancer" Study.

    Science.gov (United States)

    Rosenberg, Abby R; Bona, Kira; Wharton, Claire M; Bradford, Miranda; Shaffer, Michele L; Wolfe, Joanne; Baker, Kevin Scott

    2016-04-01

    Conducting patient-reported outcomes research with adolescents and young adults (AYAs) is difficult due to low participation rates and high attrition. Forty-seven AYAs with newly diagnosed cancer at two large hospitals were prospectively surveyed at the time of diagnosis and 3-6 and 12-18 months later. A subset participated in 1:1 semistructured interviews. Attrition prompted early study closure at one site. The majority of patients preferred paper-pencil to online surveys. Interview participants were more likely to complete surveys (e.g., 93% vs. 58% completion of 3-6 month surveys, P = 0.02). Engaging patients through qualitative methodologies and using patient-preferred instruments may optimize future research success. © 2015 Wiley Periodicals, Inc.

  7. Attrition from surgical residency training: perspectives from those who left.

    Science.gov (United States)

    Bongiovanni, Tasce; Yeo, Heather; Sosa, Julie A; Yoo, Peter S; Long, Theodore; Rosenthal, Marjorie; Berg, David; Curry, Leslie; Nunez-Smith, Marcella

    2015-10-01

    High rates of attrition from general surgery residency may threaten the surgical workforce. We sought to gain further insight regarding resident motivations for leaving general surgery residency. We conducted in-depth interviews to generate rich narrative data that explored individual experiences. An interdisciplinary team used the constant comparative method to analyze the data. Four themes characterized experiences of our 19 interviewees who left their residency program. Participants (1) felt an informal contract was breached when clinical duties were prioritized over education, (2) characterized a culture in which there was no safe space to share personal and programmatic concerns, (3) expressed a scarcity of role models who demonstrated better work-life balance, and (4) reported negative interactions with authority resulting in a profound loss of commitment. As general surgery graduate education continues to evolve, our findings may inform interventions and policies regarding programmatic changes to boost retention in surgical residency. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Task shifting for cataract surgery in eastern Africa: productivity and attrition of non-physician cataract surgeons in Kenya, Malawi and Tanzania.

    Science.gov (United States)

    Eliah, Edson; Lewallen, Susan; Kalua, Khumbo; Courtright, Paul; Gichangi, Michael; Bassett, Ken

    2014-01-01

    This project examined the surgical productivity and attrition of non-physician cataract surgeons (NPCSs) in Tanzania, Malawi, and Kenya. Baseline (2008-9) data on training, support, and productivity (annual cataract surgery rate) were collected from officially trained NPCSs using mailed questionnaires followed by telephone interviews. Telephone interviews were used to collect follow-up data annually on productivity and semi-annually on attrition. A detailed telephone interview was conducted if a surgeon left his/her post. Data were entered into and analysed using STATA. Among the 135 NPCSs, 129 were enrolled in the study (Kenya 88, Tanzania 38, and Malawi 3) mean age 42 years; average time since completing training 6.6 years. Employment was in District 44%, Regional 24% or mission/ private 32% hospitals. Small incision cataract surgery was practiced by 38% of the NPCSs. The mean cataract surgery rate was 188/year, median 76 (range 0-1700). For 39 (31%) NPCSs their surgical rate was more than 200/year. Approximately 22% in Kenya and 25% in Tanzania had years where the cataract surgical rate was zero. About 11% of the surgeons had no support staff. High quality training is necessary but not sufficient to result in cataract surgical activity that meets population needs and maintains surgical skill. Needed are supporting institutions and staff, functioning equipment and programs to recruit and transport patients.

  9. Factors Affecting Recruitment and Attrition in Randomised Controlled Trials of Complementary and Alternative Medicine for Pregnancy-Related Issues

    Directory of Open Access Journals (Sweden)

    Ciara Close

    2016-01-01

    Full Text Available Background. Randomised controlled trials (RCTs investigating Complementary and Alternative Medicine (CAM for pregnancy-related issues have encountered issues with recruitment and attrition. Little is known about the cause of these issues. Methods. Data was gathered from an antenatal CAM randomised controlled trial. During foetal anomaly appointments, women meeting inclusion criteria were invited to participate in the trial. Numbers of women invited and eligible were recorded. Reasons for noninterest were noted and analysed. Focus groups exploring trial experience of participants were also conducted. Findings. Of the 428 women invited to participate, 376 were eligible and just under a quarter participated. Reasons for nonparticipation included concerns about CAM and lack of interest in participation in research. Other factors negatively affecting recruitment included recruitment timing, competition for participants, limited support from staff, and inadequate trial promotion. Factors encouraging recruitment included being interested in research and seeking pain relief. Reasons for dropping out were time constraints, travel issues, work commitments, and pregnancy issues. Several women in the sham and usual care group dropped out due to dissatisfaction with treatment allocation. Conclusion. CAM researchers must explore problems encountered with recruitment and attrition so that evidence-based implementation strategies to address the issues can be developed.

  10. Properties and sinterability of wet and dry attrition-milled OREOXed powder

    International Nuclear Information System (INIS)

    Lee, J. W.; Kim, J. H.; Kim, W. K.; Park, K. I.; Lee, J. W.

    2001-01-01

    The powder properties and sinterability were investigated with the powder prepared by wet and dry attrition milling of OREOX-treated powder. The OREOX-treated powder was prepared from the simulated spent fuel. Powder having less than 1 μm of average particle size could be obtained by dry milling, but not be obtained by wet milling. Thus, specific surface area of dry milled powder was higher than that of wet milled powder. With increasing of milling time, dry milled powder formed dense agglomerate while wet milled powder showed loose agglomerate. The pellets with higher than 95% T.D. of sintered density and larger than 7 μm of grain size were made with the milled powder regardless of milling method. The milling time in wet milling has greatly improved the sinterability. The pellets produced with dry milled powder have higher sintered density and larger grain size

  11. Retaining the mental health nursing workforce: early indicators of retention and attrition.

    Science.gov (United States)

    Robinson, Sarah; Murrells, Trevor; Smith, Elizabeth M

    2005-12-01

    In the UK, strategies to improve retention of the mental health workforce feature prominently in health policy. This paper reports on a longitudinal national study into the careers of mental health nurses in the UK. The findings reveal little attrition during the first 6 months after qualification. Investigation of career experiences showed that the main sources of job satisfaction were caregiving opportunities and supportive working relationships. The main sources of dissatisfaction were pay in relation to responsibility, paperwork, continuing education opportunities, and career guidance. Participants were asked whether they predicted being in nursing in the future. Gender and ethnicity were related to likelihood to remain in nursing in 5 years time. Age, having children, educational background, ethnic background, and time in first job were associated with likelihood of remaining in nursing at 10 years. Associations between elements of job satisfaction (quality of clinical supervision, ratio of qualified to unqualified staff, support from immediate line manager, and paperwork) and anticipated retention are complex and there are likely to be interaction effects because of the complexity of the issues. Sustaining positive experiences, remedying sources of dissatisfaction, and supporting diplomats from all backgrounds should be central to the development of retention strategies.

  12. Computational toxicology: Its essential role in reducing drug attrition.

    Science.gov (United States)

    Naven, R T; Louise-May, S

    2015-12-01

    Predictive toxicology plays a critical role in reducing the failure rate of new drugs in pharmaceutical research and development. Despite recent gains in our understanding of drug-induced toxicity, however, it is urgent that the utility and limitations of our current predictive tools be determined in order to identify gaps in our understanding of mechanistic and chemical toxicology. Using recently published computational regression analyses of in vitro and in vivo toxicology data, it will be demonstrated that significant gaps remain in early safety screening paradigms. More strategic analyses of these data sets will allow for a better understanding of their domain of applicability and help identify those compounds that cause significant in vivo toxicity but which are currently mis-predicted by in silico and in vitro models. These 'outliers' and falsely predicted compounds are metaphorical lighthouses that shine light on existing toxicological knowledge gaps, and it is essential that these compounds are investigated if attrition is to be reduced significantly in the future. As such, the modern computational toxicologist is more productively engaged in understanding these gaps and driving investigative toxicology towards addressing them. © The Author(s) 2015.

  13. Why They Leave: The Impact of Stereotype Threat on the Attrition of Women and Minorities from Science, Math and Engineering Majors

    Science.gov (United States)

    Beasley, Maya A.; Fischer, Mary J.

    2012-01-01

    This paper examines the effects of group performance anxiety on the attrition of women and minorities from science, math, and engineering majors. While past research has relied primarily on the academic deficits and lower socioeconomic status of women and minorities to explain their absence from these fields, we focus on the impact of stereotype…

  14. Martensitic phase transformations in the nanostructured surface layers induced by mechanical attrition treatment

    International Nuclear Information System (INIS)

    Ni Zhichun; Wang Xiaowei; Wu Erdong; Liu Gang

    2005-01-01

    Conversion electron Moessbauer spectroscopy (CEMS) and x-ray diffraction (XRD) analysis have been used to investigate the relationship between characteristics of phase transformation and the treatment time in surface nanocrystallized 316L stainless steel induced by surface mechanical attrition treatment (SMAT). A similar trend of development of the martensitic phase upon the treatment time has been observed from both CEMS and XRD measurements. However, in the CEMS measurement, two types of martensite phase with different magnetic hyperfine fields are revealed. Based on a random distribution of the non-iron coordinating atoms, a three-element theoretical model is developed to illustrate the difference of two types of martensite phase. The calculated results indicate the segregation of the non-iron atoms associated with SMAT treatment

  15. Attritional rupture of extensor pollicis longus: a rare complication following elastic stable intramedullary nailing of a paediatric radial fracture.

    LENUS (Irish Health Repository)

    Sproule, James A

    2011-01-01

    Elastic stable intramedullary nail fixation has become established as an acceptable method of treatment for diaphyseal fractures of both forearm bones in the paediatric population. It is considered safe, minimally invasive and does not compromise physeal growth. We report a case of delayed rupture of extensor pollicis longus due to attrition over the sharp edges of a protruding nail end after elastic stable intramedullary nailing of a paediatric radial diaphyseal fracture.

  16. Differences in reach and attrition between Web-based and print-delivered tailored interventions among adults over 50 years of age: clustered randomized trial.

    Science.gov (United States)

    Peels, Denise Astrid; Bolman, Catherine; Golsteijn, Rianne Henrica Johanna; De Vries, Hein; Mudde, Aart Nicolaas; van Stralen, Maartje Marieke; Lechner, Lilian

    2012-12-17

    The Internet has the potential to provide large populations with individual health promotion advice at a relatively low cost. Despite the high rates of Internet access, actual reach by Web-based interventions is often disappointingly low, and differences in use between demographic subgroups are present. Furthermore, Web-based interventions often have to deal with high rates of attrition. This study aims to assess user characteristics related to participation and attrition when comparing Web-based and print-delivered tailored interventions containing similar content and thereby to provide recommendations in choosing the appropriate delivery mode for a particular target audience. We studied the distribution of a Web-based and a print-delivered version of the Active Plus intervention in a clustered randomized controlled trial (RCT). Participants were recruited via direct mailing within the participating Municipal Health Council regions and randomized to the printed or Web-based intervention by their region. Based on the answers given in a prior assessment, participants received tailored advice on 3 occasions: (1) within 2 weeks after the baseline, (2) 2 months after the baseline, and (3) within 4 months after the baseline (based on a second assessment at 3 months). The baseline (printed or Web-based) results were analyzed using ANOVA and chi-square tests to establish the differences in user characteristics between both intervention groups. We used logistic regression analyses to study the interaction between the user characteristics and the delivery mode in the prediction of dropout rate within the intervention period. The printed intervention resulted in a higher participation rate (19%) than the Web-based intervention (12%). Participants of the Web-based intervention were significantly younger (PWeb-based intervention group (53%) compared to the print-delivered intervention (39%, PWeb-based and the printed intervention was not explained by user characteristics. The

  17. The impact of assay technology as applied to safety assessment in reducing compound attrition in drug discovery.

    Science.gov (United States)

    Thomas, Craig E; Will, Yvonne

    2012-02-01

    Attrition in the drug industry due to safety findings remains high and requires a shift in the current safety testing paradigm. Many companies are now positioning safety assessment at each stage of the drug development process, including discovery, where an early perspective on potential safety issues is sought, often at chemical scaffold level, using a variety of emerging technologies. Given the lengthy development time frames of drugs in the pharmaceutical industry, the authors believe that the impact of new technologies on attrition is best measured as a function of the quality and timeliness of candidate compounds entering development. The authors provide an overview of in silico and in vitro models, as well as more complex approaches such as 'omics,' and where they are best positioned within the drug discovery process. It is important to take away that not all technologies should be applied to all projects. Technologies vary widely in their validation state, throughput and cost. A thoughtful combination of validated and emerging technologies is crucial in identifying the most promising candidates to move to proof-of-concept testing in humans. In spite of the challenges inherent in applying new technologies to drug discovery, the successes and recognition that we cannot continue to rely on safety assessment practices used for decades have led to rather dramatic strategy shifts and fostered partnerships across government agencies and industry. We are optimistic that these efforts will ultimately benefit patients by delivering effective and safe medications in a timely fashion.

  18. Psychological and sociodemographic predictors of premature discontinuation of a 1-year multimodal outpatient weight-reduction program: an attrition analysis

    Directory of Open Access Journals (Sweden)

    Liebl ME

    2012-03-01

    Full Text Available Anne Ahnis1, Andrea Riedl1, Andrea Figura1, Elisabeth Steinhagen-Thiessen2, Max E Liebl3, Burghard F Klapp11Internal Medicine and Dermatology, Medical Department, Division of Psychosomatic Medicine, Charité – Universitätsmedizin Berlin, Campus Mitte, 2Internal Medicine with Gastroenterology and Nephrology, Specialty network of Gastroenterology, Endocrinology and Metabolic Diseases, Division of Lipid Metabolism, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, 3Medical Department, Division of Rheumatology and Clinical Immunology, Department for Physical Medicine, Charité – Universitätsmedizin Berlin, Campus Mitte, Berlin, GermanyObjective: Attrition rates of up to 77% have been reported in conservative weight-reduction programs for the treatment of obesity. In view of the cost of such programs to the health system, there is a need to identify the variables that predict premature discontinuation of treatment. Previous studies have focused mainly on somatic and sociodemographic parameters. The prospective influence of psychological factors has not been systematically investigated to date.Methods: A total of 164 patients (138 of whom were women with a mean age of 45 years and a mean body mass index of 39.57 participated in a 1-year outpatient weight-reduction program at the Charité – Universitätsmedizin Berlin University Hospital. The program included movement therapy, dietary advice, psychoeducational and behavioral interventions, relaxation procedures, and consultations with a specialist in internal medicine and a psychologist. Patients also underwent regular laboratory and psychological testing. The results were evaluated using a t-test, χ2-test, and logistic regression analysis.Results: Seventy-one of the 164 patients (61 women, mean age = 43 years, mean body mass index = 39.53 withdrew before the end of the program (attrition rate = 43.3%. While there were no differences between the somatic and metabolic

  19. Attrition tendinitis of long head of biceps brachii in relation to humeral head osteonecrosis: case report.

    Science.gov (United States)

    Wiesler, Ethan R; Sarlikiotis, Thomas; Mavrogenis, Andreas F; Kokkalis, Zinon T

    2013-01-01

    This case report identifies a 41-year-old male patient who developed anterior shoulder pain in the setting of humeral head osteonecrosis. As a consequence of the cartilage degeneration, multiple loose bodies formed and migrated into the bicipital tendon sheath, causing attrition tendinitis, which was a feature of the clinical presentation. The patient was treated by a combination of arthroscopic glenohumeral joint debridement and open tenodesis of the biceps using a suture anchor. Follow-up revealed asymptomatic shoulder function by 18 months. This is the first report in the literature of bicipital tendinitis in the context of avascular necrosis of the shoulder.

  20. Risk factors for tooth wear lesions among patients attending the dental clinic of a Nigerian Teaching Hospital, Benin City: A pilot study

    Directory of Open Access Journals (Sweden)

    Okeigbemen A Sunny

    2015-01-01

    Full Text Available Aims: This study was to evaluate the risk factors associated with tooth wear lesions in patients attending a dental clinic. Context: Tooth wear lesions entail the loss of dental hard tissues in the absence of caries or trauma. They include abrasion, attrition, and erosion. The etiology is often related to habits leading to insidious symptoms with similar presentations in both community and hospital patients. Materials and Methods: This cross-sectional study involved patients attending the outpatient dental clinic of a Nigerian Teaching Hospital over a 3-month period. A semi-structured questionnaire was used to elicit information from the respondents. Results: A total of 152 respondents aged 17–80 years and above, comprising 86 males (56.6%, and 66 females (43.3% constituted the study population. The Binis were the most represented 34.2%, followed by the Esans 21.1%, while the least represented were the Yorubas (6.6%. The occupations represented in this study include civil servants (30.3%, unskilled workers (23.7%, and non-medical professionals (7.9%. Tooth wear lesions were present in 55.3% of the respondents. Attrition accounted for 29.6%, Abrasion (11.8%, combination of attrition and abrasion (4.6%, and abfraction (2.0%. There was a statistically significant association between tooth wear lesions and age, occupation, sensitivity or pain, tooth cleaning aids, toothbrush texture brushing technique, intake of carbonated beverages, and method of intake. Conclusion: Tooth wear lesions such as attrition and abrasion were prevalent among the respondents in this hospital setting and, therefore, represent an important group of dental problems among this population. It is, therefore, important to direct the appropriate oral health awareness program for the prevention, early detection, and management of these conditions.

  1. Factors affecting the attrition of community-directed distributors of ivermectin, in an onchocerciasis-control programme in the Imo and Abia states of south-eastern Nigeria.

    Science.gov (United States)

    Emukah, E C; Enyinnaya, U; Olaniran, N S; Akpan, E A; Hopkins, D R; Miri, E S; Amazigo, U; Okoronkwo, C; Stanley, A; Rakers, L; Richards, F O; Katabarwa, M N

    2008-01-01

    In areas of Nigeria where onchocerciasis is endemic, community-directed distributors (CDD) distribute ivermectin annually, as part of the effort to control the disease. Unfortunately, it has been reported that at least 35% of the distributors who have been trained in Nigeria are unwilling to participate further as CDD. The selection and training of new CDD, to replace those unwilling to continue, leads to annual expense that the national onchocerciasis-programme is finding difficult to meet, given other programme priorities and the limited resources. If the reported levels of attrition are true, they seriously threaten the sustainability of community-directed treatment with ivermectin (CDTI) in Nigeria. In 2002, interviews were held with 101 people who had been trained as CDD, including those who had stopped serving their communities, from 12 communities in south-eastern Nigeria that had high rates of CDD attrition. The results showed that, although the overall reported CDD attrition was 40.6%, the actual rate was only 10.9%. The CDD who had ceased participating in the annual rounds of ivermectin blamed a lack of incentives (65.9%), the demands of other employment (14.6%), the long distances involved in the house-to-house distribution (12.2%) or marital duties (7.3%). Analysis of the data obtained from all the interviewed CDD showed that inadequate supplies of ivermectin (P<0.01), lack of supervision (P<0.05) and a lack of monetary incentives (P<0.001) led to significant increases in attrition. Conversely, CDD retention was significantly enhanced when the distributors were selected by their community members (P<0.001), supervised (P<0.001), supplied with adequate ivermectin tablets (P<0.05), involved in educating their community members (P<0.05), and/or involved in other health programmes (P<0.001). Although CDD who were involved in other health programmes were relatively unlikely to cease participating in the distributions, they were more likely to take longer

  2. Surface mechanical attrition treatment induced phase transformation behavior in NiTi shape memory alloy

    International Nuclear Information System (INIS)

    Hu, T.; Wen, C.S.; Lu, J.; Wu, S.L.; Xin, Y.C.; Zhang, W.J.; Chu, C.L.; Chung, J.C.Y.; Yeung, K.W.K.; Kwok, D.T.K.; Chu, Paul K.

    2009-01-01

    The phase constituents and transformation behavior of the martensite B19' NiTi shape memory alloy after undergoing surface mechanical attrition treatment (SMAT) are investigated. SMAT is found to induce the formation of a parent B2 phase from the martensite B19' in the top surface layer. By removing the surface layer-by-layer, X-ray diffraction reveals that the amount of the B2 phase decreases with depth. Differential scanning calorimetry (DSC) further indicates that the deformed martensite in the sub-surface layer up to 300 μm deep exhibits the martensite stabilization effect. The graded phase structure and transformation behavior in the SMATed NiTi specimen can be attributed to the gradient change in strain with depth.

  3. The effect of ZrO2 grinding media on the attrition milling of FeAl with Y2O3

    International Nuclear Information System (INIS)

    Gedevanishvili, S.; Deevi, S.C.

    2004-01-01

    Attrition milling of water and gas atomized FeAl was carried out with Y 2 O 3 , where ZrO 2 was used as a grinding media in place of stainless steel balls to avoid contamination with Cr and C. Consolidation of the milled powders produced complex FeAl phases containing Zr which doubled the hardness and significantly improved the creep resistance as compared to that of unmilled and consolidated FeAl

  4. Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

    International Nuclear Information System (INIS)

    Samih, Youssef; Novelli, Marc; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry; Thiriet, Tony

    2014-01-01

    The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge – Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves

  5. Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

    Science.gov (United States)

    Samih, Youssef; Novelli, Marc; Thiriet, Tony; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry

    2014-08-01

    The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge - Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves.

  6. Study of possible chaotic, quasi-periodic and periodic structures in quantum dusty plasma

    International Nuclear Information System (INIS)

    Ghosh, Uday Narayan; Chatterjee, Prasanta; Roychoudhury, Rajkumar

    2014-01-01

    Existence of chaotic, quasi-periodic, and periodic structures of dust-ion acoustic waves is studied in quantum dusty plasmas through dynamical system approach. A system of coupled differential equations is derived from the fluid model and subsequently, variational matrix is obtained. The characteristic equation is obtained at the equilibrium point, and the behavior of nonlinear waves is studied numerically using Runge-Kutta method. The behavior of the dynamical system changes significantly when any of plasma parameters, such as the dust concentration parameter, temperature ratio, or the quantum diffraction parameter, is varied. The change of the characteristic of solution of the system is extensively studied. It is found that the system changes its behavior from chaotic pattern to limit cycle behavior

  7. 77 FR 73452 - Grace Period Study

    Science.gov (United States)

    2012-12-10

    ... survey may be distributed in waves for convenience. The Grace Period Study survey will be an electronic... information that is used for sampling purposes will be maintained in a separate file from the quantitative...

  8. Attrition of limestones by impact loading in fluidized beds: The influence of reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    Scala, Fabrizio [Istituto di Ricerche sulla Combustione, Consiglio Nazionale delle Ricerche, Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione, Consiglio Nazionale delle Ricerche, Napoli (Italy); Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, Napoli (Italy)

    2010-09-15

    The extent of attrition associated with impact loading was studied for five different limestones pre-processed in fluidized bed under different reaction conditions. The experimental procedure was based on the measurement of the amount and the particle size distribution of the debris generated upon impact of sorbent samples against a target at velocities between 10 and 45 m/s. The effect of calcination, sulfation and calcination/re-carbonation on impact damage was assessed. Fragmentation by impact loading of the limestones was significant and increased with the impact velocity. Lime samples displayed the largest propensity to undergo impact damage, followed by sulfated, re-carbonated and raw limestones. Fragmentation of the sulfated samples followed a pattern typical of the failure of brittle materials. On the other hand, the behaviour of lime samples better conformed to a disintegration failure mode, with extensive generation of very fine fragments. Raw limestone and re-carbonated lime samples followed either of the two patterns depending on the sorbent nature. The extent of particle fragmentation increased after multiple impacts, but the incremental amount of fragments generated upon one impact decreased with the number of successive impacts. (author)

  9. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    Science.gov (United States)

    Hopmann, Ch.; Weber, M.; van Haag, J.; Schöngart, M.

    2015-05-01

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material's properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

  10. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    International Nuclear Information System (INIS)

    Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M.

    2015-01-01

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA

  11. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    Energy Technology Data Exchange (ETDEWEB)

    Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M. [Institute of Plastics Processing (IKV) at RWTH Aachen University, Pontstr. 49, 52062 Aachen (Germany)

    2015-05-22

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

  12. Assessing the Potential for Bias From Nonresponse to a Study Follow-up Interview: An Example From the Agricultural Health Study.

    Science.gov (United States)

    Rinsky, Jessica L; Richardson, David B; Wing, Steve; Beard, John D; Alavanja, Michael; Beane Freeman, Laura E; Chen, Honglei; Henneberger, Paul K; Kamel, Freya; Sandler, Dale P; Hoppin, Jane A

    2017-08-15

    Prospective cohort studies are important tools for identifying causes of disease. However, these studies are susceptible to attrition. When information collected after enrollment is through interview or exam, attrition leads to missing information for nonrespondents. The Agricultural Health Study enrolled 52,394 farmers in 1993-1997 and collected additional information during subsequent interviews. Forty-six percent of enrolled farmers responded to the 2005-2010 interview; 7% of farmers died prior to the interview. We examined whether response was related to attributes measured at enrollment. To characterize potential bias from attrition, we evaluated differences in associations between smoking and incidence of 3 cancer types between the enrolled cohort and the subcohort of 2005-2010 respondents, using cancer registry information. In the subcohort we evaluated the ability of inverse probability weighting (IPW) to reduce bias. Response was related to age, state, race/ethnicity, education, marital status, smoking, and alcohol consumption. When exposure and outcome were associated and case response was differential by exposure, some bias was observed; IPW conditional on exposure and covariates failed to correct estimates. When response was nondifferential, subcohort and full-cohort estimates were similar, making IPW unnecessary. This example provides a demonstration of investigating the influence of attrition in cohort studies using information that has been self-reported after enrollment. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Retention and attrition factors for female certified athletic trainers in the National Collegiate Athletic Association Division I Football Bowl Subdivision setting.

    Science.gov (United States)

    Goodman, Ashley; Mensch, James M; Jay, Michelle; French, Karen E; Mitchell, Murray F; Fritz, Stacy L

    2010-01-01

    Organizational effectiveness and the continuity of patient care can be affected by certain levels of attrition. However, little is known about the retention and attrition of female certified athletic trainers (ATs) in certain settings. To gain insight and understanding into the factors and circumstances affecting female ATs' decisions to persist in or leave the National Collegiate Athletic Association Division I Football Bowl Subdivision (NCAA D-I FBS) setting. Qualitative study. The 12 NCAA D-I FBS institutions within the Southeastern Conference. A total of 23 women who were current full-time ATs (n = 12) or former full-time ATs (n = 11) at Southeastern Conference institutions participated. Data were collected via in-depth, semistructured interviews, transcribed verbatim, and analyzed via a grounded theory approach. Peer review and member checking methods were performed to establish trustworthiness. The decision to persist involved 4 main factors: (1) increased autonomy, (2) increased social support, (3) enjoyment of job/fitting the NCAA D-I mold, and (4) kinship responsibility. Two subfactors of persistence, the NCAA D-I atmosphere and positive athlete dynamics, emerged under the main factor of enjoyment of job/fitting the NCAA D-I mold. The decision to leave included 3 main factors: (1) life balance issues, (2) role conflict and role overload, and (3) kinship responsibility. Two subfactors of leaving, supervisory/coach conflict and decreased autonomy, emerged under the main factor of role conflict and role overload. A female AT's decision to persist in or leave the NCAA D-I FBS setting can involve several factors. In order to retain capable ATs long term in the NCAA D-I setting, an individual's attributes and obligations, the setting's cultural issues, and an organization's social support paradigm should be considered.

  14. Early predictors of study success in a Dutch advanced nurse practitioner education program: A retrospective cohort study.

    Science.gov (United States)

    Bossema, Ercolie R; Meijs, Tineke H J M; Peters, Jeroen W B

    2017-10-01

    Study delay and attrition are major concerns in higher education. They cost time and effort, and threaten the availability of higher qualified professionals. Knowing early what factors contribute to delay and attrition may help prevent this. The aim of this study was to examine whether student characteristics, including a literature study report grade as a proxy of cognitive abilities, predicted study success in a dual advanced nurse practitioner education program. Retrospective cohort study, including all 214 students who between September 2009 and September 2015 started the two-year program at the HAN University of Applied Sciences in Nijmegen, the Netherlands. Study success was defined as having completed the program within the envisaged period. Variables examined included: age, gender, previous education (bachelor's degree or in-service training in nursing), work setting (general health, mental health, public health, or nursing home care), and literature study report grade (from 1 to 10). A hierarchical logistic regression analysis was performed. Most students were female (80%), had a bachelor's degree in nursing (67%), and were employed in a general healthcare setting (58%). Mean age was 40.5years (SD 9.4). One hundred thirty-seven students (64%) had study success. Being employed in a general healthcare setting (p≤0.004) and a higher literature study report grade (p=0.001) were associated with a higher study success rate. In advanced nurse practitioner education, study success rate seems associated with the student's cognitive abilities and work field. It might be worthwhile to identify students 'at risk of failure' before the start of the program and offer them extra support. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Treatment initiation, program attrition and patient treatment outcomes associated with scale-up and decentralization of HIV care in rural Malawi.

    Science.gov (United States)

    McGuire, Megan; Pinoges, Loretxu; Kanapathipillai, Rupa; Munyenyembe, Tamika; Huckabee, Martha; Makombe, Simon; Szumilin, Elisabeth; Heinzelmann, Annette; Pujades-Rodríguez, Mar

    2012-01-01

    To describe patient antiretroviral therapy (cART) outcomes associated with intensive decentralization of services in a rural HIV program in Malawi. Longitudinal analysis of data from HIV-infected patients starting cART between August 2001 and December 2008 and of a cross-sectional immunovirological assessment conducted 12 (±2) months after therapy start. One-year mortality, lost to follow-up, and attrition (deaths and lost to follow-up) rates were estimated with exact Poisson 95% confidence intervals (CI) by type of care delivery and year of initiation. Association of virological suppression (centralized care and 11,090 decentralized care. At therapy start, patients treated in decentralized health facilities had higher median CD4 count levels (167 vs. 130 cell/µL, Pdecentralized than centralized facilities (9.9 per 100 person-years, 95% CI: 9.5-10.4 vs. 20.8 per 100 person-years, 95% CI: 19.7-22.0). One year after treatment start, differences in immunological success (adjusted OR=1.23, 95% CI: 0.83-1.83), and viral suppression (adjusted OR=0.80, 95% CI: 0.56-1.14) between patients followed at centralized and decentralized facilities were not statistically significant. In rural Malawi, 1- and 2-year program attrition was lower in decentralized than in centralized health facilities and no statistically significant differences in one-year immunovirological outcomes were observed between the two health care levels. Longer follow-up is needed to confirm these results.

  16. Accelerated telomere attrition is associated with relative household income, diet and inflammation in the pSoBid cohort.

    Directory of Open Access Journals (Sweden)

    Paul G Shiels

    Full Text Available It has previously been hypothesized that lower socio-economic status can accelerate biological ageing, and predispose to early onset of disease. This study investigated the association of socio-economic and lifestyle factors, as well as traditional and novel risk factors, with biological-ageing, as measured by telomere length, in a Glasgow based cohort that included individuals with extreme socio-economic differences.A total of 382 blood samples from the pSoBid study were available for telomere analysis. For each participant, data was available for socio-economic status factors, biochemical parameters and dietary intake. Statistical analyses were undertaken to investigate the association between telomere lengths and these aforementioned parameters.The rate of age-related telomere attrition was significantly associated with low relative income, housing tenure and poor diet. Notably, telomere length was positively associated with LDL and total cholesterol levels, but inversely correlated to circulating IL-6.These data suggest lower socio-economic status and poor diet are relevant to accelerated biological ageing. They also suggest potential associations between elevated circulating IL-6, a measure known to predict cardiovascular disease and diabetes with biological ageing. These observations require further study to tease out potential mechanistic links.

  17. Long-period and short-period variations of ionospheric parameters studied from complex observations performed on Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Laso, B; Lobachevskii, L A; Potapova, N I; Freizon, I A; Shapiro, B S

    1980-09-01

    Cuban data from 1978 are used to study long-period (i.e., diurnal) variations of Doppler shift on a 3000 km path at frequencies of 10 and 15 MHz these variations are related to variations of parameters on the ionospheric path. Short-period variations were also studied on the basis of Doppler shift data and vertical sounding data in the 0.000111-0.00113 Hz frequency range. The relation between the observed variations and internal gravity waves are discussed.

  18. The effects of three different food acids on the attrition-corrosion wear of human dental enamel

    Science.gov (United States)

    Zhang, Yichi; Arsecularatne, Joseph A.; Hoffman, Mark

    2015-07-01

    With increased consumption of acidic drinks and foods, the wear of human teeth due to attrition in acidic environments is an increasingly important issue. Accordingly, the present paper investigates in vitro the wear of human enamel in three different acidic environments. Reciprocating wear tests in which an enamel cusp slides on an enamel flat surface were carried out using acetic, citric and lactic acid lubricants (at pH 3-3.5). Distilled water was also included as a lubricant for comparison. Focused ion beam milling and scanning electron microscopy imaging were then used to investigate the enamel subsurfaces following wear tests. Nanoindentation was used to ascertain the changes in enamel mechanical properties. The study reveals crack generation along the rod boundaries due to the exposure of enamel to the acidic environments. The wear mechanism changes from brittle fracture in distilled water to ploughing or shaving of the softened layer in acidic environments, generating a smooth surface with the progression of wear. Moreover, nanoindentation results of enamel samples which were exposed to the above acids up to a duration of the wear tests show decreasing hardness and Young’s modulus with exposure time.

  19. Attitudes and factors contributing to attrition in Canadian surgical specialty residency programs.

    Science.gov (United States)

    Adams, Simon; Ginther, David Nathan; Neuls, Evan; Hayes, Paul

    2017-08-01

    We recently studied attrition in Canadian general surgical programs; however, there are no data on whether residents enrolled in other surgical residencies harbour the same intents as their general surgical peers. We sought to determine how many residents in surgical disciplines in Canada consider leaving their programs and why. An anonymous survey was administered to all residents in 9 surgical disciplines in Canada. Significance of association was determined using the Pearson χ2 test. The Canadian Post-MD Education Registry (CAPER) website was used to calculate the response rate. We received 523 responses (27.6% response rate). Of these respondents, 140 (26.8%) were either "somewhat" or "seriously" considering leaving their program. Residents wanting to pursue additional fellowship training and those aspiring to an academic career were significantly less likely to be considering changing specialties ( p = 0.003 and p = 0.005, respectively). Poor work-life balance and fear of unemployment/underemployment were the top reasons why residents would change specialty (55.5% and 40.8%, respectively), although the reasons cited were not significantly different between those considering changing and those who were not ( p = 0.64). Residents who were considering changing programs were significantly less likely to enjoy their work and more likely to cite having already invested too much time to change as a reason for continuing ( p work-life balance and limited employment prospects. Efforts to educate prospective residents about the reality of the surgical lifestyle and to optimize employment prospects may improve completion rates.

  20. Why do faculty leave? Reasons for attrition of women and minority faculty from a medical school: four-year results.

    Science.gov (United States)

    Cropsey, Karen L; Masho, Saba W; Shiang, Rita; Sikka, Veronica; Kornstein, Susan G; Hampton, Carol L

    2008-09-01

    Faculty attrition, particularly among female and minority faculty, is a serious problem in academic medical settings. The reasons why faculty in academic medical settings choose to leave their employment are not well understood. Further, it is not clear if the reasons why women and minority faculty leave differ from those of other groups. One hundred sixty-six medical school faculty who left the School of Medicine (SOM) between July 1, 2001, and June 30, 2005, completed a survey about their reasons for leaving. The three most common overall reasons for leaving the institution included career/professional advancement (29.8%), low salary (25.5%), and chairman/departmental leadership issues (22.4%). The ranking of these reasons varied slightly across racial and gender groups, with women and minority faculty also citing personal reasons for leaving. Women and minority faculty were at lower academic ranks at the time they left the SOM compared with male and majority groups. Although salary differences were not present at the time of initial hire, sex was a significant predictor of lower salary at the start of the new position. Opportunity for advancement and the rate of promotion were significantly different between women and men. Job characteristics prior to leaving that were rated most poorly were protected time for teaching and research, communication across the campus, and patient parking. Harassment and discrimination were reported by a small number of those surveyed, particularly women and minority faculty. The majority of reasons for faculty attrition are amenable to change. Retaining high-quality faculty in medical settings may justify the costs of faculty development and retention efforts.

  1. Thermoelectric properties of Bi2Te3-Bi2Se3 solid solutions prepared by attrition milling and hot pressing

    International Nuclear Information System (INIS)

    Lee, Go-Eun; Kim, Il-Ho; Choi, Soon-Mok; Lim, Young-Soo; Seo, Won-Seon; Park, Jae-Soung; Yang, Seung-Ho

    2014-01-01

    Bi 2 Te 3-y Se y (y = 0.15 - 0.6) solid solutions were prepared by attrition milling and hot pressing. The lattice constants decreased with increasing Se content, indicating that the Se atoms were successfully substituted into the Te sites. All specimens exhibited n-type conduction, and their electrical resistivities increased slightly with increasing temperature. With increasing Se content, the Seebeck coefficients increased while the thermal conductivity decreased due to the increase in phonon scattering. The maximum figure of merit obtained was 0.63 at 440 K for the undoped Bi 2 Te 2.4 Se 0.6 solid solution.

  2. Attrition and Opportunities Along the HIV Care Continuum: Findings From a Population-Based Sample, North West Province, South Africa.

    Science.gov (United States)

    Lippman, Sheri A; Shade, Starley B; El Ayadi, Alison M; Gilvydis, Jennifer M; Grignon, Jessica S; Liegler, Teri; Morris, Jessica; Naidoo, Evasen; Prach, Lisa M; Puren, Adrian; Barnhart, Scott

    2016-09-01

    Attrition along the HIV care continuum slows gains in mitigating the South African HIV epidemic. Understanding population-level gaps in HIV identification, linkage, retention in care, and viral suppression is critical to target programming. We conducted a population-based household survey, HIV rapid testing, point-of-care CD4 testing, and viral load measurement from dried blood spots using multistage cluster sampling in 2 subdistricts of North West Province from January to March, 2014. We used weighting and multiple imputation of missing data to estimate HIV prevalence, undiagnosed infection, linkage and retention in care, medication adherence, and viral suppression. We sampled 1044 respondents aged 18-49. HIV prevalence was 20.0% (95% confidence interval: 13.7 to 26.2) for men and 26.7% (95% confidence interval: 22.1 to 31.4) for women. Among those HIV positive, 48.4% of men and 75.7% of women were aware of their serostatus; 44.0% of men and 74.8% of women reported ever linking to HIV care; 33.1% of men and 58.4% of women were retained in care; and 21.6% of men and 50.0% of women had dried blood spots viral loads <5000 copies per milliliter. Among those already linked to care, 81.7% on antiretroviral treatment (ART) and 56.0% of those not on ART were retained in care, and 51.8% currently retained in care on ART had viral loads <5000 copies per milliliter. Despite expanded treatment in South Africa, attrition along the continuum of HIV care is slowing prevention progress. Improved detection is critically needed, particularly among men. Reported linkage and retention is reasonable for those on ART; however, failure to achieve viral suppression is worrisome.

  3. Personality Disorder in Adult Attention-Deficit/Hyperactivity Disorder: Attrition and Change During Long-term Treatment.

    Science.gov (United States)

    Gift, Thomas E; Reimherr, Frederick W; Marchant, Barrie K; Steans, Tammy A; Wender, Paul H

    2016-05-01

    Personality disorders (PDs) are commonly found in adults with attention-deficit/hyperactivity disorder (ADHD) and are associated with increased ADHD symptoms and psychosocial impairment. To assess the impact of PDs or personality traits on retention rates in ADHD trials and whether treating ADHD affects the expression of PD, data were analyzed from 2 methylphenidate trials. Assessment of PDs and personality traits included using the Wisconsin Personality Disorders Inventory IV and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Personality Disorders. Attention-deficit/hyperactivity disorder symptoms were evaluated using the Wender-Reimherr Adult Attention Deficit Disorder Scale. Major findings were that subjects with cluster A, cluster B, passive-aggressive, or more than 1 PD showed more attrition. Subjects dropping out also had more schizoid and narcissistic traits. Attention-deficit/hyperactivity disorder symptoms (p Disorders Inventory IV items that improved most, 8 resembled ADHD or oppositional defiant disorder symptoms.

  4. Nurses graduating in Fiji between 2001 and 2010: sufficient supply for Fiji's health service demands?

    Science.gov (United States)

    Aiyub, S; Linh, N N; Tayler-Smith, K; Khogali, M; Bissell, K

    2013-03-21

    Fiji's schools of nursing and government health services, 2001-2010. To report on 1) the number and characteristics of nurses who graduated in Fiji, 2) the proportion of vacant nursing positions in the government health services and 3) attrition among nurses. Descriptive study involving a retrospective record review of Ministry of Health annual reports and nursing registers. Over the period 2001-2010, a total of 1500 nurses graduated, with the overall trend being a gradual increase in newly qualified nurses year on year. Available data from 2007 onwards showed relatively low vacancy rates (range 0.4-2%), with a sharp rise to 15% in 2009. Complete data on nurse attrition were available only from 2007 onwards, with rates of attrition ranging from 4% to 10%; the most common reason for attrition was resignation. While it was unable to directly assess whether Fiji's supply of nursing graduates has been meeting the country's health service demands, this study provides a series of baseline data on Fiji's nurse graduate and nursing workforce. In addition, it identifies some of the challenges and gaps that need to be considered to better assess and address nursing staff shortages.

  5. Prevention of weld-decay in austenitic stainless steel by using surface mechanical attrition treatment

    Science.gov (United States)

    Laleh, Majid; Kargar, Farzad; Rouhaghdam, Alireza Sabour

    2012-11-01

    Surface mechanical attrition treatment (SMAT) was applied to the samples of a type AISI 304 stainless steel in order to induce grain refinement as well as formation of twins. Transmission electron microscopy and X-ray diffraction analysis results showed that the average grain size at the surface of the SMATed sample was about 10 nm. The untreated and SMATed samples were then welded using a one-pass gas tungsten arc procedure. The heat-affected zone (HAZ) of the samples was examined by optical microscopy and corrosion tests. Results of the double loop electrochemical potentiokinetic reactivation tests showed that the degree of sensitization in the HAZ for the SMATed sample was very low as compared to that of the untreated one. The pre-SMATed sample was resistant to intergranular corrosion. This is mainly due to the formation of high density of twins which are not prone to carbide precipitation because of their regular and coherent atomic structure and extreme low grain boundary energy as compared with those of other grain boundaries.

  6. POSSIBILITY OF BENEFICIATION OF SILICA SAND FROM THE CROATIAN DEPOSITS USING ATTRITION SCRUBBING

    Directory of Open Access Journals (Sweden)

    Ivan Sobota

    2011-12-01

    Full Text Available To meet high quality requirements defined for specific industrial applications, the raw sand often has to be subjected to extensive physical and chemical processing. The possibility of achieving silica sand concentrate of required quality depends mostly on raw sand properties, primarily mineral impurity types and contents, and features of applied beneficiation methods. When the impurities occur in the form of oxide coatings on the surfaces of the single sand grains, attriton scrubbing is applied. By reducing the proportion of oxide coatings on the grains, the quality of sand can be improved. With the aim to determine the possibilities of the beneficiation of silica sand from significant Croatian deposits (“Vrtlinska”, “Štefanac” and “Španovica” and achieve concentrate grade complying with the requirements of domestic industry, laboratory tests were conducted on three raw sand samples with different SiO2 and impurity contents. Grain size distribution, chemical and mineral composition of raw sand samples, and the possibility of their quality improvement by applying the washing, classification and attrition scrubbing were defined by analysis of test results (the paper is published in Croatian.

  7. Cognitive Ageing in Great Britain in the New Century: Cohort Differences in Episodic Memory.

    Directory of Open Access Journals (Sweden)

    Gindo Tampubolon

    Full Text Available Dementias in high income countries are set to be the third major burden of disease even as older people are increasingly required to think for themselves how to provide for their lives in retirement. Meanwhile the period of older age continues to extend with increase in life expectancy. This challenge demands an understanding of how cognition changes over an extended period in later life. But studying cognitive ageing in the population faces a difficulty from the fact that older respondents are liable to leave (attrite before study completion. This study tested three hypotheses: trajectories of cognitive ageing in Britain show an improvement beyond the age of 50; and they are lifted by secular improvement in cognition across cohorts; lastly they are susceptible to distortion due to attrition.Using the English Longitudinal Study of Ageing, this paper studied trajectories of episodic memory of Britons aged 50-89 from 2002 to 2013 (N = 5931. Using joint models the analysis found that levels of episodic memory follow a curvilinear shape, not a steady decline, in later life. The findings also revealed secular improvement in cognitive ageing such that as a cohort is being replaced episodic memory levels in the population improve. The analysis lastly demonstrated that failure to simultaneously model attrition can produce distorted pictures of cognitive ageing.Old age in this century is not necessarily a period dominated by cognitive decline. In identifying behavioural factors associated with better cognitive ageing, such as social connections of traditional and online kinds, the paper raises possibilities of mustering an adequate response to the cognition challenge.

  8. Pooling Data from Multiple Longitudinal Studies: The Role of Item Response Theory in Integrative Data Analysis

    Science.gov (United States)

    Curran, Patrick J.; Hussong, Andrea M.; Cai, Li; Huang, Wenjing; Chassin, Laurie; Sher, Kenneth J.; Zucker, Robert A.

    2010-01-01

    There are a number of significant challenges encountered when studying development over an extended period of time including subject attrition, changing measurement structures across group and developmental period, and the need to invest substantial time and money. Integrative data analysis is an emerging set of methodologies that overcomes many of the challenges of single sample designs through the pooling of data drawn from multiple existing developmental studies. This approach is characterized by a host of advantages, but this also introduces several new complexities that must be addressed prior to broad adoption by developmental researchers. In this paper we focus on methods for fitting measurement models and creating scale scores using data drawn from multiple longitudinal studies. We present findings from the analysis of repeated measures of internalizing symptomatology that were pooled from three existing developmental studies. We describe and demonstrate each step in the analysis and we conclude with a discussion of potential limitations and directions for future research. PMID:18331129

  9. Period variation studies of six contact binaries in M4

    Science.gov (United States)

    Rukmini, Jagirdar; Shanti Priya, Devarapalli

    2018-04-01

    We present the first period study of six contact binaries in the closest globular cluster M4 the data collected from June 1995‑June 2009 and Oct 2012‑Sept 2013. New times of minima are determined for all the six variables and eclipse timing (O-C) diagrams along with the quadratic fit are presented. For all the variables, the study of (O-C) variations reveals changes in the periods. In addition, the fundamental parameters for four of the contact binaries obtained using the Wilson-Devinney code (v2003) are presented. Planned observations of these binaries using the 3.6-m Devasthal Optical Telescope (DOT) and the 4-m International Liquid Mirror Telescope (ILMT) operated by the Aryabhatta Research Institute of Observational Sciences (ARIES; Nainital) can throw light on their evolutionary status from long term period variation studies.

  10. Localized solid-state amorphization at grain boundaries in a nanocrystalline Al solid solution subjected to surface mechanical attrition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, X [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Tao, N [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Hong, Y [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Lu, J [LASMIS, University of Technology of Troyes, 10000, Troyes (France); Lu, K [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2005-11-21

    Using high-resolution electron microscopy, localized solid-state amorphization (SSA) was observed in a nanocrystalline (NC) Al solid solution (weight per cent 4.2 Cu, 0.3 Mn, the rest being Al) subjected to a surface mechanical attrition treatment. It was found that the deformation-induced SSA may occur at the grain boundary (GB) where either the high density dislocations or dislocation complexes are present. It is suggested that lattice instability due to elastic distortion within the dislocation core region plays a significant role in the initiation of the localized SSA at defective sites. Meanwhile, the GB of severely deformed NC grains exhibits a continuously varying atomic structure in such a way that while most of the GB is ordered but reveals corrugated configurations, localized amorphization may occur along the same GB.

  11. Optimal recall period for caregiver-reported illness in risk factor and intervention studies: a multicountry study.

    Science.gov (United States)

    Arnold, Benjamin F; Galiani, Sebastian; Ram, Pavani K; Hubbard, Alan E; Briceño, Bertha; Gertler, Paul J; Colford, John M

    2013-02-15

    Many community-based studies of acute child illness rely on cases reported by caregivers. In prior investigations, researchers noted a reporting bias when longer illness recall periods were used. The use of recall periods longer than 2-3 days has been discouraged to minimize this reporting bias. In the present study, we sought to determine the optimal recall period for illness measurement when accounting for both bias and variance. Using data from 12,191 children less than 24 months of age collected in 2008-2009 from Himachal Pradesh in India, Madhya Pradesh in India, Indonesia, Peru, and Senegal, we calculated bias, variance, and mean squared error for estimates of the prevalence ratio between groups defined by anemia, stunting, and underweight status to identify optimal recall periods for caregiver-reported diarrhea, cough, and fever. There was little bias in the prevalence ratio when a 7-day recall period was used (<10% in 35 of 45 scenarios), and the mean squared error was usually minimized with recall periods of 6 or more days. Shortening the recall period from 7 days to 2 days required sample-size increases of 52%-92% for diarrhea, 47%-61% for cough, and 102%-206% for fever. In contrast to the current practice of using 2-day recall periods, this work suggests that studies should measure caregiver-reported illness with a 7-day recall period.

  12. Maternal lifetime history of depression and depressive symptoms in the prenatal and early postnatal period do not predict infant-mother attachment quality in a large, population-based Dutch cohort study.

    Science.gov (United States)

    Tharner, Anne; Luijk, Maartje P C M; van Ijzendoorn, Marinus H; Bakermans-Kranenburg, Marian J; Jaddoe, Vincent W V; Hofman, Albert; Verhulst, Frank C; Tiemeier, Henning

    2012-01-01

    We examined the effects of maternal history of depressive disorder and the effects of depressive symptoms during pregnancy and the early postpartum period on attachment insecurity and disorganization. A total of 627 mother-infant dyads from the Generation R Study participated in a population-based cohort from fetal life onwards. Maternal history of depression was assessed by diagnostic interviews during pregnancy; maternal peri- and postnatal depressive symptoms were assessed with questionnaires in 506 of these women at 20 weeks pregnancy and two months postpartum; and infant-mother attachment security was observed when infants were aged 14 months. A history of maternal depressive disorder, regardless of severity or psychiatric comorbidity, was not associated with an increased risk of infant attachment insecurity or disorganization. Likewise, maternal peri- and postnatal depressive symptoms were not related to attachment insecurity or disorganization at 14 months. These results are important because mothers from otherwise low risk backgrounds often have previously been depressed or are struggling with non-clinical depressive symptoms during pregnancy and after giving birth. Our findings are discussed in terms of protective factors that may limit the potentially negative effects of maternal depressive symptoms on the infant-mother attachment relationship in the general population. The role of selective attrition and lack of information about the mothers' attachment status for the current null-findings are also discussed.

  13. Why (and how) they decide to leave: A grounded theory analysis of STEM attrition at a large public research university

    Science.gov (United States)

    Minutello, Michael F.

    A grounded theory investigation of STEM attrition was conducted that describes and explains why undergraduates at a large Mid-Atlantic research university decided to leave their initial STEM majors to pursue non-STEM courses of study. Participants ultimately decided to leave their initial STEM majors because they were able to locate preferable non-STEM courses of study that did not present the same kinds of obstacles they had encountered in their original STEM majors. Grounded theory data analysis revealed participants initially enrolled in STEM majors with tenuous motivation that did not withstand the various obstacles that were present in introductory STEM coursework. Obstacles that acted as demotivating influences and prompted participants to locate alternative academic pathways include the following: (1.) disengaging curricula; (2.) competitive culture; (3.) disappointing grades; (4.) demanding time commitments; and (5.) unappealing career options. Once discouraged from continuing along their initial STEM pathways, participants then employed various strategies to discover suitable non-STEM majors that would allow them to realize their intrinsic interests and extrinsic goals. Participants were largely satisfied with their decisions to leave STEM and have achieved measures of personal satisfaction and professional success.

  14. Experimental study of microstructure changes due to low cycle fatigue of a steel nanocrystallised by Surface Mechanical Attrition Treatment (SMAT)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Z. [ICD, P2MN, LASMIS, University of Technology of Troyes, UMR 6281, CNRS, Troyes (France); Retraint, D., E-mail: delphine.retraint@utt.fr [ICD, P2MN, LASMIS, University of Technology of Troyes, UMR 6281, CNRS, Troyes (France); Baudin, T.; Helbert, A.L.; Brisset, F. [ICMMO, Univ Paris-Sud, Université Paris-Saclay, UMR CNRS 8182, 91405 Orsay Cedex (France); Chemkhi, M.; Zhou, J. [ICD, P2MN, LASMIS, University of Technology of Troyes, UMR 6281, CNRS, Troyes (France); Kanouté, P. [ICD, P2MN, LASMIS, University of Technology of Troyes, UMR 6281, CNRS, Troyes (France); ONERA, The French Aerospace Lab, 29 avenue de la Division Leclerc, 92322 Chatillon Cedex (France)

    2017-02-15

    Electron Backscatter Diffraction technique is used to characterize the microstructure of 316L steel generated by Surface Mechanical Attrition Treatment (SMAT) before and after low cycle fatigue tests. A grain size gradient is generated from the top surface to the interior of the samples after SMAT so that three main regions can be distinguished below the treated surface: (i) the ultra-fine grain area within 5 μm under the top surface with preferably oriented grains, (ii) the intermediate area where the original grains are partially transformed, and (iii) the edge periphery area where the original grains are just mechanically deformed with the presence of plastic slips. Fatigue tests show that cyclic loading does not change the grain orientation spread and does not activate any plastic slip in the ultra-fine grain top surface area induced by SMAT. On the opposite, in the plastically SMAT affected region including the intermediate area and the edge periphery area, new slip systems are activated by low cycle fatigue while the grain orientation spread is increased. These results represent a first very interesting step towards the characterization and understanding of mechanical mechanisms involved during the fatigue of a grain size gradient material. - Highlights: •LCF tests are carried out on specimens processed by SMAT. •EBSD is used to investigate microstructural changes induced by LCF. •A grain size gradient is generated by SMAT from surface to the bulk of the fatigue samples. •New slip systems are activated by LCF and GOS is increased in plastically deformed region. •However, these phenomena are not observed in the top surface ultra-fine grain area.

  15. Experimental study of microstructure changes due to low cycle fatigue of a steel nanocrystallised by Surface Mechanical Attrition Treatment (SMAT)

    International Nuclear Information System (INIS)

    Sun, Z.; Retraint, D.; Baudin, T.; Helbert, A.L.; Brisset, F.; Chemkhi, M.; Zhou, J.; Kanouté, P.

    2017-01-01

    Electron Backscatter Diffraction technique is used to characterize the microstructure of 316L steel generated by Surface Mechanical Attrition Treatment (SMAT) before and after low cycle fatigue tests. A grain size gradient is generated from the top surface to the interior of the samples after SMAT so that three main regions can be distinguished below the treated surface: (i) the ultra-fine grain area within 5 μm under the top surface with preferably oriented grains, (ii) the intermediate area where the original grains are partially transformed, and (iii) the edge periphery area where the original grains are just mechanically deformed with the presence of plastic slips. Fatigue tests show that cyclic loading does not change the grain orientation spread and does not activate any plastic slip in the ultra-fine grain top surface area induced by SMAT. On the opposite, in the plastically SMAT affected region including the intermediate area and the edge periphery area, new slip systems are activated by low cycle fatigue while the grain orientation spread is increased. These results represent a first very interesting step towards the characterization and understanding of mechanical mechanisms involved during the fatigue of a grain size gradient material. - Highlights: •LCF tests are carried out on specimens processed by SMAT. •EBSD is used to investigate microstructural changes induced by LCF. •A grain size gradient is generated by SMAT from surface to the bulk of the fatigue samples. •New slip systems are activated by LCF and GOS is increased in plastically deformed region. •However, these phenomena are not observed in the top surface ultra-fine grain area.

  16. The Views of Ex-Police Officers on Child Abuse Case Attrition in the United Kingdom.

    Science.gov (United States)

    Krahenbuhl, Sarah J; Dent, Helen R

    2017-11-01

    Attrition in child abuse cases is of continuing concern. International research has produced evidence to suggest that the form and quality of the evidence available in many child abuse cases is of insufficient quality to allow progression through the judicial system. Recent revelations have led to an increase in public and professional awareness of the prevalence of child sexual abuse, and how this is managed by the legal and social care systems. The aim of this research was to explore the opinions of ex-Police Officers who had direct experience relating to the management of child abuse cases about the factors affecting case progression. Seven ex-Police Officers were interviewed and the transcribed data were thematically analyzed. The five main themes derived from the data were Global Myths, Assumptions, and Misconceptions; Suitability; Resources; Professionals' Attributes; and Working Together. These themes demonstrated that the primary issues indicated by ex-Police Officers were more about relationships between professionals, an understanding of the child's perspective, and their subsequent involvement in the legal processes than simply being related to a lack of resources.

  17. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    DEFF Research Database (Denmark)

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH solution O3 P is formed in a small...

  18. Radioecological studies in early period of NIRS

    International Nuclear Information System (INIS)

    Ichikawa, Ryushi

    2004-01-01

    Japanese tuna-fishing boat Fukuryumaru No.5 was exposed to heavy radioactive fallout due to the nuclear test explosion carried out by U.S.A. at Bikini Atoll of Marshal Islands in the central part of Pacific Ocean on March 1, 1954. Following this accident, radioactivity was detected in various environmental samples including rain, marine fishes and agricultural crops. Science Council of Japan organized the new research group of many scientists in the field of fisheries, agricultural, medical and biological studies and radiation protection studies. Government of Japan established National Institute of Radiological Sciences (NIRS) in 1957. In this Institute various radioecological studies have been carried out. In this paper, some of these radioecological studies carried out in early period of NIRS are described. (author)

  19. Baseline Patient Characteristics Predicting Outcome and Attrition in Cognitive Therapy for Social Phobia: Results from a Large Multicentre Trial.

    Science.gov (United States)

    Hoyer, Juergen; Wiltink, Joerg; Hiller, Wolfgang; Miller, Robert; Salzer, Simone; Sarnowsky, Stephan; Stangier, Ulrich; Strauss, Bernhard; Willutzki, Ulrike; Leibing, Eric

    2016-01-01

    We examined the role of baseline patient characteristics as predictors of outcome (end-state functioning, response and remission) and attrition for cognitive therapy (CT) in social anxiety disorder (SAD). Beyond socio-demographic and clinical variables such as symptom severity and comorbidity status, previously neglected patient characteristics (e.g., personality, self-esteem, shame, interpersonal problems and attachment style) were analysed. Data came from the CT arm of a multicentre RCT with n = 244 patients having DSM-IV SAD. CT was conducted according to the manual by Clark and Wells. Severity of SAD was assessed at baseline and end of treatment with the Liebowitz Social Anxiety Scale (LSAS). Multiple linear regression analyses and logistic regression analyses were applied. Up to 37% of the post-treatment variance (LSAS) could be explained by all pre-treatment variables combined. Symptom severity (baseline LSAS) was consistently negatively associated with end-state functioning and remission, but not with response. Number of comorbid diagnoses was negatively associated with end-state functioning and response, but not with remission. Self-esteem was positively associated with higher end-state functioning and more shame with better response. Attrition could not be significantly predicted. The results indicate that the initial probability for treatment success mainly depends on severity of disorder and comorbid conditions while other psychological variables are of minor importance, at least on a nomothetic level. This stands in contrast with efforts to arrive at an empirical-based foundation for differential indication and argues to search for more potent moderators of therapeutic change rather on the process level. Personality, self-esteem, shame, attachment style and interpersonal problems do not or only marginally moderate the effects of interventions in CT of social phobia. Symptom severity and comorbid diagnoses might affect treatment outcome negatively

  20. Relationship between neurocognition and functional recovery in first-episode schizophrenia: Results from the second year of the Oslo multi-follow-up study.

    Science.gov (United States)

    Torgalsbøen, Anne-Kari; Mohn, Christine; Czajkowski, Nikolai; Rund, Bjørn Rishovd

    2015-06-30

    Lack of control of confounding variables, high attrition rate, and too few neurocognitive domains completed at each assessment point are some of the limitations identified in studies of the relationship between cognition and functional outcome in schizophrenia. In the ongoing Oslo multi-follow-up study 28 first episode schizophrenia patients and a pairwise matched control group (N=28) are assessed with the MATRICS Consensus Cognitive Battery (MCCB), a clinical interview, an inventory on social and role functioning and criteria of remission and recovery at several follow-up points. The current paper describes the rate of remission and full recovery, and investigates the relationship between neurocognition and functional outcome. At 2-year follow-up, 80.0% of the patients were in remission and 16.0% of them fulfilled the criteria for full recovery. The attrition rate was very low. In the follow-up period, there was a statistically significant decline in Verbal Learning and a significant improvement on Reasoning/Problem Solving and Social Cognition in the schizophrenia group, but not in the control group. This indicates a differentiated neurocognitive course. In the schizophrenia group, Attention/Vigilance and years of education at baseline were significant predictors of social and role functioning 2 years later. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Surface mechanical attrition treatment of tungsten and its behavior under low energy deuterium plasma implantation relevant to ITER divertor conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.Y.; Yuan, Y.; Fu, B.Q.; Godfrey, A.; Liu, W. [Tsinghua Univ.. Lab. of Advanced Materials, Beijing (China); Zhang, Y.B. [Technical Univ. og Denmark. DTU Risoe Campus, Roskilde (Denmark); Tao, N.R. [Chinese Academy of Sciences, Shenyang (China)

    2012-11-01

    In the light of a foreseen application for tungsten (W) as an ITER divertor material samples have been plastically deformed by a surface mechanical attrition treatment (SMAT) and by cold rolling. The resistance to blister formation by low energy deuterium implantation in these samples has been examined, with the result that the structure is significantly improved as the structural scale is reduced to the nanometer range in the SMAT sample. The distribution of blisters in this sample is however bimodal, due to the formation of several very large blisters, which are heterogeneously distributed. The observations suggest that process optimization must be a next step in the development with a view to the application of plastically deformed W in a fusion reactor. (Author)

  2. Not by strength alone : children's conflict expectations follow the logic of the asymmetric war of attrition.

    Science.gov (United States)

    Pietraszewski, David; Shaw, Alex

    2015-03-01

    The Asymmetric War of Attrition (AWA) model of animal conflict in evolutionary biology (Maynard Smith and Parker in Nature, 246, 15-18, 1976) suggests that an organism's decision to withdraw from a conflict is the result of adaptations designed to integrate the expected value of winning, discounted by the expected costs that would be incurred by continuing to compete, via sensitivity to proximate cues of how quickly each side can impose costs on the other (Resource Holding Potential), and how much each side will gain by winning. The current studies examine whether human conflict expectations follow the formalized logic of this model. Children aged 6-8 years were presented with third-party conflict vignettes and were then asked to predict the likely winner. Cues of ownership, hunger, size, strength, and alliance strength were systematically varied across conditions. Results demonstrate that children's expectations followed the logic of the AWA model, even in complex situations featuring multiple, competing cues, such that the actual relative costs and benefits that would accrue during such a conflict were reflected in children's expectations. Control conditions show that these modifications to conflict expectations could not have resulted from more general experimental artifacts or demand characteristics. To test the selectivity of these effects to conflict, expectations of search effort were also assessed. As predicted, they yielded a different pattern of results. These studies represent one of the first experimental tests of the AWA model in humans and suggest that future research on the psychology of ownership, conflict, and value may be aided by formalized models from evolutionary biology.

  3. Undergraduate Navigator Training Attrition Study

    Science.gov (United States)

    1975-11-01

    stabilization. The Masculinity- Feminity Scale (SVIB), significant at the .05 level, contributed 1.73% to the predicted variance. High scores (those...8217 a iiiftihlilfft-tMJ ^^mm^mmmwm^mmmmm mmmmm Do you have extensive experience in athletic competition? If so, what sport (s) and what kind of...machinery? For example, farm equipment, construction equipment. Do you have extensive experience in athletic competition? If so, what sport (s) and what

  4. Comparative study of thyrotoxic periodic paralysis from idiopathic hypokalemic periodic paralysis: An experience from India

    Directory of Open Access Journals (Sweden)

    J Kalita

    2012-01-01

    Full Text Available Objective: There is paucity of reports on thyrotoxic periodic paralysis (TPP from India. We report the patients with TPP and compare them with idiopathic hypokalemic periodic paralysis (IHPP. Materials and Methods: Patients with hypokalemic periodic paralysis (HPP treated during the past 11 years were evaluated retrospectively. Their demographic parameters, family history, clinical features, precipitating factors, severity of weakness, laboratory parameters and rapidity of recovery were recorded. The demographic, clinical and laboratory parameters of TPP and IHPP were compared. Results: During the study period, we managed 52 patients with HPP; nine (17.3% of whom had TPP and 27 (52% had IHPP. The demographic, precipitating factors, number of attacks and severity of limb weakness were similar between the TPP and IHPP groups, except in the IHPP group, bulbar weakness was present in four and respiratory paralysis in six, needing artificial ventilation in two patients. Serum potassium was significantly lower in TPP (2.21 ± 0.49 compared with IHPP (2.67 ± 0.59, P = 0.04. Four patients with TPP had subclinical thyrotoxicosis and two had subclinical hyperthyroidism. Rebound hyperkalemia occurred in both TPP and IHPP (three versus eight patients. The recovery was faster in IHPP (26.7 ± 15.4 h compared with TPP (34.0 ± 14.0 h, but was statistically insignificant. Conclusion: TPP constitutes 17.3% of HPP, and absence of clinical features of thyrotoxicosis and subclinical hyperthyroidism in TPP is not uncommon. Clinical features, demographic profile and rebound hyperkalemia are similar in both TPP and IHPP. The serum potassium level is significantly low in the TPP compared with the IHPP group.

  5. Does one size fit all? A study of beginning science and mathematics teacher induction

    Science.gov (United States)

    Kralik, Jeffrey M.

    Over the past few years, many induction programs have been implemented across the country, primarily designed to limit the amount beginning teacher attrition. Few of these programs have focused on improving teacher quality or identifying the specific needs of individual teachers. Research suggests that beginning science and mathematics teachers have specific needs that are not being met by current induction models, possibly resulting in higher rates of attrition. Harry and Janet Knowles created the Knowles Science Teaching Foundation (KSTF) to identify and support young scientists and mathematicians as they dedicate their lives to teaching young people. Through financial, curricular, and emotional support, KSTF encourages new teachers to remain in teaching and become leaders in their schools and districts. This dissertation is a sequential explanatory study, which first establishes national estimates for beginning teacher attrition rates and the reasons for the migration based on subject area taught, with an emphasis on mathematics and science teachers. This study then evaluates the KSTF model through multiple methods---analysis of KSTF survey data and interviews with KSTF participants and stakeholders.

  6. Refinement of Crystalline Boron and the Superconducting Properties of MgB2 by Attrition Ball Milling

    International Nuclear Information System (INIS)

    Lee, J. H.; Shin, S. Y.; Park, H. W.; Jun, B. H.; Kim, C. J.

    2008-01-01

    We report refinement of crystalline boron by an attrition ball milling system and the superconducting properties of the MgB 2 pellets prepared from the refined boron. In this work, we have conducted the ball milling with only crystalline boron powder, in order to improve homogeneity and control the grain size of the MgB 2 that is formed from it. We observed that the crystalline responses in the ball-milled boron became broader and weaker when the ball-milling time was further increased. On the other hand, the B 2 O 3 peak became stronger in the powders, resulting in an increase in the amount of MgO within the MgB 2 volume. The main reason for this is a greater oxygen uptake. From the perspective of the superconducting properties, however, the sample prepared from boron that was ball milled for 5 hours showed an improvement of critical current density (J c ), even with increased MgO phase, under an external magnetic field at 5 and 20 K.

  7. A randomized trial of energy-restricted high-protein versus high-carbohydrate, low-fat diet in morbid obesity.

    Science.gov (United States)

    Dalle Grave, Riccardo; Calugi, Simona; Gavasso, Ilaria; El Ghoch, Marwan; Marchesini, Giulio

    2013-09-01

    Conflicting evidence exists as to weight loss produced by diets with different carbohydrate/protein ratio. The aim was to compare the long-term effects of high-protein vs. high-carbohydrate diet (HPD, HCD), combined with cognitive behavior therapy (CBT). In a randomized trial, 88 obese participants (mean age, 46.7; mean BMI, 45.6 kg m(-2) ) were enrolled in a 3-week inpatient and 48-week outpatient treatment, with continuous CBT during the study period. All subjects consumed a restricted diet (1,200 kcal day(-1) for women, 1,500 for men; 20% energy from fat, fat). HPD derived 34% energy from proteins, 46% from carbohydrates; HCD 17% from proteins, 64% from carbohydrates. The primary outcome was 1-year percent weight loss. Secondary outcomes were attrition rates and changes in cardiovascular risk factors and psychological profile. Attrition rates were similar between groups (25.6%). In the intention-to-treat analysis, weight loss averaged 15.0% in HPD and 13.3% in HCD at 1 year, without any difference throughout the study period. Both diets produced a similar improvement in secondary outcomes. The relative carbohydrate and protein content of the diet, when combined with intensive CBT, does not significantly affect attrition rate, weight loss and psychosocial outcome in patients with severe obesity. Copyright © 2013 The Obesity Society.

  8. The Role of Attrition and Solids Recovery in a Chemical Looping Combustion Process Effet de l’attrition et de la récupération des particules dans le procédé de combustion en boucle chimique

    Directory of Open Access Journals (Sweden)

    Kramp M.

    2011-05-01

    Full Text Available In the present work, the steady-state behavior of a Chemical Looping Combustion process of interconnected fluidized bed reactors is simulated. The simulations have been carried out in two different scales, 50 kWth and 100 MWth. Attrition model derived from small scale laboratory experiments has been employed for the prediction of the process behavior in terms of attrition and Oxygen Carrier loss. Information on Oxygen Carrier characteristics and reaction kinetics were taken from literature. Realistic circulation mass flows of Oxygen Carrier particles are obtained and Oxygen Carrier losses are quantified. The large scale process looses significantly more Oxygen Carrier than the small scale process based on the same amount of thermal energy produced. Incomplete conversion in the air reactor could be identified as a critical point. Another issue is the fuel gas bypassing the Oxygen Carrier particles through bubbles in the large scale process which leads to lowered fuel conversions. The simulations indicate that a similar performance of a pilot scale and a large scale process is not guaranteed due to the scale-up effect on fluid dynamics. Furthermore, the simulations allow an assessment of the influence of the quality of the solids recovery system on the Oxygen Carrier loss. The distribution of the losses between possible origins is investigated and different changes in the solids recovery system are discussed regarding their potential to decrease the Oxygen Carrier loss. For example, the addition of a second-stage cyclone after the air reactor of the large scale process reduces the Oxygen Carrier loss significantly. Le présent travail propose un modèle de simulation en continu du procédé de combustion en boucle chimique constitué de deux lits fluidisés interconnectés. Les simulations ont été conduites à deux échelles 50 kWth correspondant à une installation pilote et 100 MWth correspondant à une installation industrielle. Un modèle d

  9. Sintering Studies of Ga-Doped CeO2 (Ga-Doped PuO2 Surrogate) for Mixed Oxide Nuclear Fuel

    International Nuclear Information System (INIS)

    Haertling, C.; Huling, J.; Park, Y.S.

    1999-01-01

    Sintering studies of CeO 2 and CeO 2 + 2 wt. % Ga 2 O 3 were completed. Firing temperatures studied were 1250-1650 C with 2 to 4 hour firing soak times in air. Powders fabricated by three methods (as-received, attrition-mill and nitrite-derived) were studied. Attrition-milled CeO 2 improved densities as compared with as-received CeO 2 . Attrition-milled CeO 2 with 2 wt.% Ga 2 O 3 showed decreased densities with increasing temperatures. As-received CeO 2 with 2 wt.% Ga 2 O 3 showed a opposite trend, increasing in density with increased firing temperature. Two pellet preparation methods were studied, a one-step-press method and a two-step-press method. The two-step-press method showed greater densities at lower firing temperatures and times as compared with the one-step-press method, however for CeO 2 + 2 wt.% Ga 2 O 3 , the two methods gave equivalent results at 1650 C, 6 hr. firing conditions

  10. A Period Study of the Near Contact Binary EG Cep

    Directory of Open Access Journals (Sweden)

    Chun-Hwey Kim

    2006-06-01

    Full Text Available New eight times of minimum light of the near-contact binary EG Cep were presented. All times of minimum light for EG Cep, including ours, were collected and analyzed to study it's orbital period variation. It was found that the orbital period have varied in a cyclical way superposed on an upward parabola. A secular period increase of 3.22 times 10^{-8} d/y was calculated. Under the assumption of a conservative mass transfer, it implied that the stellar gaseous material of about 3.18 times 10^{-8} rm M_odot /year is transferring from the less massive secondary component to the primary. The cyclical period variation was interpreted as light-time effect due to an unseen third body in the system. The resultant period, semi-amplitude and eccentricity of the light time orbit were calculated to be 38.^{rm y}4, 0.^{rm d}0034 and 0.29, respectively. The mass range of the tertiary proposed in the system is deduced to be quite small as 0.10M_{odot} leq M_3 leq 0.21M_{odot} for i_3 g!

  11. A use study of speech pathology and audiology periodicals at Illinois State University.

    Science.gov (United States)

    Duran, N; Buckley, C E; Ng, M L

    1997-01-01

    No core list of periodicals exists for speech pathology and audiology. Faced with the prospect of having to cancer periodicals for all subjects, the science librarians at Illinois State University decided to determine which science periodicals were used most heavily. A one-year study of science periodical reshelving and interlibrary loan requests yielded ranked lists of periodicals important to speech pathology and audiology faculty and students at Illinois State University. The three most heavily used journals were the Journal of Speech and Hearing Research, ASHA, and Topics in Language Disorders. Most of the periodicals on the lists were indexed by either MEDLINE or UnCover, or by both. While the lists of journals developed in the study are not sufficient to serve as true core lists, they should be useful to libraries supporting comparable programs in speech pathology and audiology. PMID:9431426

  12. Incubation period and immune function: A comparative field study among coexisting birds

    Science.gov (United States)

    Palacios, M.G.; Martin, T.E.

    2006-01-01

    Developmental periods are integral components of life history strategies that can have important fitness consequences and vary enormously among organisms. However, the selection pressures and mechanisms causing variation in length of developmental periods are poorly understood. Particularly puzzling are prolonged developmental periods, because their selective advantage is unclear. Here we tested the hypotheses that immune function is stronger in species that are attacked at a higher rate by parasites and that prolonged embryonic development allows the development of this stronger immune system. Through a comparative field study among 12 coexisting passerine bird species, we show that species with higher blood parasite prevalence mounted stronger cellular immune responses than species with lower prevalence. These results provide support for the hypothesis that species facing greater selection pressure from parasites invest more in immune function. However, species with longer incubation periods mounted weaker cellular immune responses than species with shorter periods. Therefore, cellular immune responses do not support the hypothesis that longer development time enhances immunocompentence. Future studies should assess other components of the immune system and test alternative causes of variation in incubation periods among bird species. ?? Springer-Verlag 2005.

  13. The outcome at 12 months of very-Iow-birth-weight infants ventilated ...

    African Journals Online (AJOL)

    Main outcome measures. Attrition rates for rural and urban babies, BPD, ROP, IVH and abnormal motor development. Study population and setting. All ventilated VLBW infants discharged from the neonatal intensive care unit at Tygerberg Hospital over a 1-year period were followed up at 3-monthly intervals for 12 months.

  14. Medical doctors profile in Ethiopia: production, attrition and retention. In memory of 100-years Ethiopian modern medicine & the new Ethiopian millennium.

    Science.gov (United States)

    Berhan, Yifru

    2008-01-01

    took the lions share of medical doctors. In short, in December 2006, 80.3% of regional hospitals were equipped with 0-2 specialists of one kind, and in 48.7% there were 0-3 General practitioners. Highest medical doctors annual attrition rates (20%-54.3%) were found in 1991-1992, 1998, 2002-2006. In general, in 20 years period (1987-2006), 73.2% of Ethiopian medical doctors left the public sector mainly due to attractive remuneration in overseas countries and local NGOs/private sectors. The number of postgraduate programme in Addis Ababa, Jimma and Gondar medical schools in December 2006 was 22, 12 and 3, respectively. The total number of fully employed academic staff of the medical schools in declining order was Addis Ababa 181, Gondar 118, Jimma 71, Hawassa 63 and Mekele 52: those with second degree and above being 97.2%, 35.6%, 90.1%, 55.6% and 15.4%, respectively. Currently (2006), there are about 416 clinical residents in 3 medical schools. High annual attrition rate, fast population growth, governmental and nongovernmental health institution expansion, low production and increased postgraduate enrollment in the last 3-4 years contributed for extremely low physician-to-population ratio in Ethiopia. Although the Ethiopian government and private sector worked and achieved much on health infrastructure construction and midlevel health professionals training, it does not appear that medical doctors retention mechanisms are sorted out so far. As a result, even despite salary equivalent top up payments in some regions, more than 80% of public hospitals outside Addis Ababa were found ill-equipped with the most important human element--physicians. This implies that the push factors may not invariably correlate with remuneration. It is high time that the government discusses the possible solutions among health professional associations/societies and other health stakeholders, and apply concrete medical doctors retention mechanisms before the public medical schools and

  15. A review of studies concerning treatment adherence of patients with anxiety disorders

    Directory of Open Access Journals (Sweden)

    Santana L

    2011-08-01

    Full Text Available Lívia Santana1, Leonardo F Fontenelle1–31Anxiety and Depression Research Program, Institute of Psychiatry, Universidade Federal do Rio de Janeiro, Brazil; 2Department of Psychiatry and Mental Health, Institute of Community Health, Universidade Federal Fluminense, Brazil; 3D’Or Institute for Research and Education (IDOR, Rio de Janeiro, BrazilObjective: This paper aimed at describing the most consistent correlates and/or predictors of nonadherence to treatment of patients with different anxiety disorders.Method: The authors retrieved studies indexed in PubMed/MedLine, PsycINFO, and ISI Web of Knowledge using the following search terms: attrition OR dropout OR attrition rates OR patient dropouts OR treatment adherence AND anxiety disorders. Research was limited to articles published before January 2010.Results: Sixteen studies were selected that investigated the impact of sociodemographic, clinical, or cognitive variables on adherence to treatment for anxiety disorders. While no consistent pattern of sociodemographic or clinical features associated with nonadherence emerged, all studies that investigated cognitive variables in panic disorder, social anxiety disorder, and obsessive-compulsive disorder found that expectations and opinions about treatment were related to adherence.Conclusion: The findings of this study suggest that it is essential to consider anxiety disorder patients’ beliefs about illness and treatment strategies to increase their compliance with the therapeutic plan.Keywords: attrition, dropout, OCD, obsessive-compulsive disorder, social anxiety disorder

  16. [Studies on flomoxef in the perinatal period].

    Science.gov (United States)

    Cho, N; Fukunaga, K; Kunii, K; Kobayashi, I

    1991-06-01

    Pharmacokinetic, bacteriological and clinical studies on flomoxef (FMOX) in the perinatal period were carried out with the following summary of the results. Antibacterial effects of FMOX on the growth of methicillin-resistant Staphylococcus aureus (MRSA, MIC 400 micrograms/ml), methicillin-sensitive S. aureus (MSSA, MIC 0.78 microgram/ml), Escherichia coli (MIC 3.13 micrograms/ml and MIC 0.20 microgram/ml) in amniotic fluid were determined and it was found that the activity of FMOX was enhanced in the amniotic fluid. FMOX rapidly penetrated into tissues and sera of pregnant women upon intravenous injection and its maternal serum concentrations reached their peak levels shortly after administration. Placental penetration of FMOX to the fetus was good and, after single intravenous injection of 1 g, the concentrations of FMOX in the umbilical cord serum and amniotic fluid exceeded MICs against major causative organisms of perinatal infections. These results indicate that single intravenous injection of FMOX 1 g twice a day is effective for the treatment and prophylaxis of perinatal infections. Injection of FMOX for the treatment of 14 cases of puerperal infections showed excellent clinical effectiveness with 100% clinical effect and 81.8% bacteriological response. No side-effect was observed in any case. All of these results suggested clinical usefulness of FMOX in the perinatal period.

  17. Study for elevator cage position during the braking period

    Science.gov (United States)

    Ungureanu, M.; Crăciun, I.; Bănică, M.; Dăscălescu, A.

    2016-08-01

    An important problem in order to study an elevator cage position for its braking period is to establish a correlation between the studies in the fields of mechanics and electric. The classical approaches to establish the elevator kinematic parameters are position, velocity and acceleration, but the last studies performed in order to determine the positioning performed by introducing supplementary another parameter - the jerk- which is derived with respect to time of acceleration. Thus we get a precise method for cage motion control for third-order trajectory planning.

  18. Roadside Accumulation of Pt, Pd, Rh and Other Trace Elements From Automobiles: Catalytic Converter Attrition and Platinum-Group Element Mobility in the Roadside Environment.

    Science.gov (United States)

    Ely, J. C.; Dahlheimer, S. R.; Neal, C. R.

    2003-12-01

    Elemental abundances of Pt, Pd and Rh have been documented across the industrialized world in roadside environments due to attrition of automotive catalytic converters (Zereini and Alt, 2000, Anthropogenic PGE Emissions, Springer, 308pp; Ely et al., 2001, EnvSci&Tech, 35:3816-3822; Whiteley and Murray, 2003, SciTotEnv, in press). In our ongoing study, the highest reported roadside Pt abundance 1.8 ppm has been found immediately adjacent to the road at a field site in South Bend, IN, USA. Furthermore, initial studies show positive correlations of Pt, Pd and Rh with some trace elements (Ni, Cu, Zn and Pb), which has been confirmed by further analysis for these and other elements (Ce, Cr). It has been demonstrated that elements such as Ce are present in catalytic converters at concentrations of 100's ppm to 3-wt.%. These elements are also being attrited with Pt, Pd and Rh and aerially transported and deposited. Our field site was established next to US-933 adjacent to the Notre Dame campus. Areas were cleared of the top 2-4 cm of soil (removing surficial Pt, Pd and Rh) at 1, 5, 10 and 50 meters from the roadside. Within 3 months the 1-meter site contained 67% of the initial Rh and Pt concentrations and 100% of the initial Pd concentration. The sites at 5, 10 and 50 meters showed similar results, in some cases exceeding the initial concentrations. After 6 months the concentrations of Pt, Pd and Rh were all within error of the initial concentrations, indicating steady state abundances had probably been reached. Grass samples from each site showed that washed vs. unwashed samples were within error of each other, and there may be a slight enrichment (approx. 1 ppb) in the grasses of Pd and Pt, but this enrichment was independent of distance from the road. The steady-state situation suggests that the PGEs are being removed from the immediate roadside environment, which requires that the metals are being oxidized and/or complexed in such a way to facilitate transport. The

  19. Moessbauer studies on ancient Chinese pottery of Yangshao Culture Period

    International Nuclear Information System (INIS)

    Yu Zhengfang; Zheng Qi; Zheng Yufang; Zhongshan Univ., Guangzhou

    1988-01-01

    Eleven pieces of ancient Chinese pottery (4770 B.C. - 2960 B.C.) of Yangshao Culture Period collected from the Xi'an area have been studied by means of Moessbauer spectroscopy. The samples were refired up to 1100 0 C in steps of 100 0 C for 2 h in air. The highest temperature up to which the Moessbauer pattern remains basically unchanged can be identified with the original firing temperature. The result indicates that the firing temperatures for most of the sherds were between 900-1000 0 C. The function of the grit contained in the pottery has been discussed. The crimson and reddish painted materials on the surface of sherds have been studied, respectively. The first appearance of pottery can probably be traced back to an even earlier period. (orig.)

  20. Moessbauer studies on ancient Chinese pottery of Yangshao Culture Period

    Energy Technology Data Exchange (ETDEWEB)

    Zhengfang, Yu; Qi, Zheng; Yufang, Zheng

    1988-02-01

    Eleven pieces of ancient Chinese pottery (4770 B.C. - 2960 B.C.) of Yangshao Culture Period collected from the Xi'an area have been studied by means of Moessbauer spectroscopy. The samples were refired up to 1100/sup 0/C in steps of 100/sup 0/C for 2 h in air. The highest temperature up to which the Moessbauer pattern remains basically unchanged can be identified with the original firing temperature. The result indicates that the firing temperatures for most of the sherds were between 900-1000/sup 0/C. The function of the grit contained in the pottery has been discussed. The crimson and reddish painted materials on the surface of sherds have been studied, respectively. The first appearance of pottery can probably be traced back to an even earlier period.

  1. [Pharmacokinetic and clinical studies of flomoxef in the perinatal period].

    Science.gov (United States)

    Matsuda, S; Hirayama, H; Oh, K; Tamate, K; Sengoku, K; Ishikawa, M; Shimizu, T; Haga, H; Hasegawa, T; Takada, H

    1993-07-01

    Pharmacokinetic and clinical studies on flomoxef (FMOX) in the perinatal period were carried out and following results were obtained 1. The pharmacokinetic parameter T1/2's of FMOX in maternal serum, umbilical cord serum and amniotic fluid in mothers after single intravenous injection of 1 g (n = 46) and 2 g (n = 34) were 1.11, 9.24, 9.24 hours and 2.54, 12.49, 12.49 hours, respectively. Cmax's and Tmax's of umbilical cord serum and amniotic fluid were 12.71, 11.77 micrograms/ml and 0.57, 3.35 hours upon single dose of 1 g i.v., and 35.17, 12.37 micrograms/ml and 0.32, 3.42 hours upon single dose of 2 g i.v., respectively. 2. Clinical usefulness were evaluated in 93 cases including were various infections in pregnancy and puerperal period. In pregnancy cases, clinical efficacy rate was 95.5% (21/22), and 100% in puerperal period. Bacteriological response rate was 84.6% (eradicated: 29, decreased: 4, unchanged: 2, replaced: 4 and unknown: 8 cases). No severe side effects nor clinical laboratory test results were observed in any cases. From above basic and clinical results, we conclude that FMOX is a useful and safe agent for various infections in pregnancy and puerperal period.

  2. Response problems in a vacation panel study

    Science.gov (United States)

    Christine A. Vogt; Susan I. Stewart

    2001-01-01

    This paper investigates response problems encountered in a panel study of travel behavior. Though the overall response rate to the three-wave panel study was acceptable (over 60%), three types of response problems were encountered: refusal, non-response, and attrition. In a follow-up phone survey, a sample of individuals from each problem response group was questioned...

  3. Studies of particle drying using non-invasive Raman spectrometry and particle size analysis.

    Science.gov (United States)

    Hamilton, Peter; Littlejohn, David; Nordon, Alison; Sefcik, Jan; Slavin, Paul; Dallin, Paul; Andrews, John

    2011-05-21

    The evaporation of methanol from needle-shaped particles of cellobiose octaacetate (COA) has been studied directly in a jacketed vacuum drier using in situ measurements by Raman spectrometry. A design of experiments (DoE) approach was used to investigate the effects of three parameters (method of agitation, % solvent loss on drying and jacket temperature), with the intention of minimising the drying time and extent of particle attrition. Drying curves based on Raman signals for methanol and COA in the spectra of the wet particles indicated the end of drying and revealed three stages in the drying process that could be used to monitor the progress of solvent removal in real time. Off-line particle size measurements based on laser diffraction were made to obtain information on the extent of attrition, to compare with the trends revealed by the Raman drying curves. The study demonstrated that non-invasive Raman spectrometry can be used to study the progress of drying during agitation of particles in a vacuum drier, allowing optimisation of operating conditions to minimise attrition and reduce drying times. Although a correlation between particle size and off-line Raman measurements of COA was demonstrated, it was not possible to derive equivalent information from the in situ Raman spectra owing to the greater effects of particle motion or bulk density variations of the particles in the drier.

  4. Theoretical model simulations for the global Thermospheric Mapping Study (TMS) periods

    Science.gov (United States)

    Rees, D.; Fuller-Rowell, T. J.

    Theoretical and semiempirical models of the solar UV/EUV and of the geomagnetic driving forces affecting the terrestrial mesosphere and thermosphere have been used to generate a series of representative numerical time-dependent and global models of the thermosphere, for the range of solar and geoamgnetic activity levels which occurred during the three Thermospheric Mapping Study periods. The simulations obtained from these numerical models are compared with observations, and with the results of semiempirical models of the thermosphere. The theoretical models provide a record of the magnitude of the major driving forces which affected the thermosphere during the study periods, and a baseline against which the actual observed structure and dynamics can be compared.

  5. European wind power integration study. Periodic report 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-31

    This periodic report no. 1 describes the work done in the Danish part of the European Wind Power Integration Study in the period until 1.4.1991. The R and D project was initiated January 1, 1989 upon prior establishment of registration equipment at 7 wind farms and at the Tjaereborg turbine. ELSAM and the meteorological service centre in Karup (VTC-Karup) have supplied data for the task. Wind Predictability, Potential and Benefits, Wind Farm - Grid Interface, Distribution System Strength, Wind Farm Cost and Operation, and Co-generation Wind Turbines/Other renewables were measured and modelled. The statistical distribution of the wind speed variations (changes in wind speed from one period of time to another) has been established with great certainty in the report. The wind speed variations follow a Weibull distribution, irrespective of the time intervals with which the data are considered. Duration curves and power distributions for the 7 wind farms have been estimated. Registration equipment for one-minute measurements was chosen in order to clarify the short-term variations in the wind power production. The possibility of working out production forecasts, to be applied in the daily load dispatching, were to be assessed for the total amount of wind power production in Jutland and Funen. The report has examined whether it would be possible to have only one wind measurement and then let it be `guiding` for the total wind farm production. Some simulations are to be carried out in the attempt to set up guidelines for the connection between the strength of distribution systems and the requirements which must be made to the wind farms which are to be places in the system. (EG)

  6. Do leukocyte telomere length dynamics depend on baseline telomere length? An analysis that corrects for ‘regression to the mean’

    International Nuclear Information System (INIS)

    Verhulst, Simon; Aviv, Abraham; Benetos, Athanase; Berenson, Gerald S.; Kark, Jeremy D.

    2013-01-01

    Leukocyte telomere length (LTL) shortens with age. Longitudinal studies have reported accelerated LTL attrition when baseline LTL is longer. However, the dependency of LTL attrition on baseline LTL might stem from a statistical artifact known as regression to the mean (RTM). To our knowledge no published study of LTL dynamics (LTL and its attrition rate) has corrected for this phenomenon. We illustrate the RTM effect using replicate LTL measurements, and show, using simulated data, how the RTM effect increases with a rise in stochastic measurement variation (representing LTL measurement error), resulting in spurious increasingly elevated dependencies of attrition on baseline values. In addition, we re-analyzed longitudinal LTL data collected from four study populations to test the hypothesis that LTL attrition depends on baseline LTL. We observed that the rate of LTL attrition was proportional to baseline LTL, but correction for the RTM effect reduced the slope of the relationship by 57 % when measurement error was low (coefficient of variation ∼2 %). A modest but statistically significant effect remained however, indicating that high baseline LTL is associated with higher LTL attrition even when correcting for the RTM effect. Baseline LTL explained 1.3 % of the variation in LTL attrition, but this effect, which differed significantly between the study samples, appeared to be primarily attributable to the association in men (3.7 %)

  7. Local thermal property analysis by scanning thermal microscopy of an ultrafine-grained copper surface layer produced by surface mechanical attrition treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, F.A. [Suzhou Institute for Nonferrous Metals Processing Technology, No. 200 Shenxu Road, Suzhou Industrial Park, Suzhou 215021 (China) and Unite de Thermique et d' Analyse Physique, Laboratoire d' Energetique et d' Optique, Universite de Reims, BP 1039, 51687 Reims Cedex 2 (France)]. E-mail: guofuan@yahoo.com; JI, Y.L. [Suzhou Institute for Nonferrous Metals Processing Technology, No. 200 Shenxu Road, Suzhou Industrial Park, Suzhou 215021 (China); Trannoy, N. [Unite de Thermique et d' Analyse Physique, Laboratoire d' Energetique et d' Optique, Universite de Reims, BP 1039, 51687 Reims Cedex 2 (France); Lu, J. [LASMIS, Universite de Technologie de Troyes, 12 Rue Marie Curie, Troyes 10010 (France)

    2006-06-15

    Scanning thermal microscopy (SThM) was used to map thermal conductivity images in an ultrafine-grained copper surface layer produced by surface mechanical attrition treatment (SMAT). It is found that the deformed surface layer shows different thermal conductivities that strongly depend on the grain size of the microstructure: the thermal conductivity of the nanostructured surface layer decreases obviously when compared with that of the coarse-grained matrix of the sample. The role of the grain boundaries in thermal conduction is analyzed in correlation with the heat conduction mechanism in pure metal. A theoretical approach, based on this investigation, was used to calculate the heat flow from the probe tip to the sample and then estimate the thermal conductivities at different scanning positions. Experimental results and theoretical calculation demonstrate that SThM can be used as a tool for the thermal property and microstructural analysis of ultrafine-grained microstructures.

  8. Interspecific studies of circadian genes period and timeless in Drosophila.

    Science.gov (United States)

    Noreen, Shumaila; Pegoraro, Mirko; Nouroz, Faisal; Tauber, Eran; Kyriacou, Charalambos P

    2018-03-30

    The level of rescue of clock function in genetically arrhythmic Drosophila melanogaster hosts using interspecific clock gene transformation was used to study the putative intermolecular coevolution between interacting clock proteins. Among them PER and TIM are the two important negative regulators of the circadian clock feedback loop. We transformed either the D. pseudoobscura per or tim transgenes into the corresponding arrhythmic D. melanogaster mutant (per01 or tim01) and observed >50% rhythmicity but the period of activity rhythm was either longer (D. pseudoobscura-per) or shorter than 24 h (D. pseudoobscura-tim) compared to controls. By introducing both transgenes simultaneously into double mutants, we observed that the period of the activity rhythm was rescued by the pair of hemizygous transgenes (~24 h). These flies also showed a more optimal level of temperature compensation for the period. Under LD 12:12 these flies have a D. pseudoobscura like activity profile with the absence of morning anticipation as well as a very prominent earlier evening peak of activity rhythm. These observation are consistent with the view that TIM and PER form a heterospecific coevolved module at least for the circadian period of activity rhythms. However the strength of rhythmicity was reduced by having both transgenes present, so while evidence for a coevolution between PER and TIM is observed for some characters it is not for others. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Study of the influence in crystallization period in MCM-22 zeolite synthesis

    International Nuclear Information System (INIS)

    Barbosa, A.S.; Santos, E.R.F.; Rodrigues, M.G.F.

    2011-01-01

    The synthesis of MCM-22 is accomplished by hydrothermal treatment and long periods needed for crystallization, with the gradual growth of crystals of 10-14 days. MCM-22 catalyst is studied intensively as promising, with high thermal stability. As part of a line of research focused on the development of zeolite with lowest cost, this study aimed to examine the effect in decreasing the period of crystallization in the synthesis of zeolite MCM-22. The materials were characterized by X-ray diffraction (XRD) spectroscopy, X-ray Energy Dispersive (EDX) and Fourier transform infrared spectroscopy and Fourier transform (FT-IR). By XRD it was observed that the hydrothermal treatment used in the synthesis was effective during periods of crystallization and EDX was observed that the samples have a high percentage of silica and low alumina content, which gives them a high ratio SiO 2 /Al 2 O 3 characteristic of the MWW structure. (author)

  10. Estimating Treatment Effects from Contaminated Multi-Period Education Experiments: The Dynamic Impacts of Class Size Reductions. NBER Working Paper No. 15200

    Science.gov (United States)

    Ding, Weili; Lehrer, Steven F.

    2009-01-01

    This paper introduces an empirical strategy to estimate dynamic treatment effects in randomized trials that provide treatment in multiple stages and in which various noncompliance problems arise such as attrition and selective transitions between treatment and control groups. Our approach is applied to the highly influential four year randomized…

  11. Forecasting demand for single-period products : A case study in the apparel industry

    NARCIS (Netherlands)

    Mostard, Julien; Teunter, Ruud; de Koster, Rene

    2011-01-01

    The problem considered is that of forecasting demand for single-period products before the period starts. We study this problem for the case of a mail order apparel company that needs to order its products pre-season. The lack of historical demand data implies that other sources of data are needed.

  12. Ready for university? A cross national study on students' perceived preparedness for university

    NARCIS (Netherlands)

    Jansen, E.P.W.A.; van der Meer, J.

    Students' preparedness for higher education is seen as one of the main factors affecting first-year attrition or study success. In this paper we report on a cross-national study in which students' preparedness for university was measured before students commenced their study at a university in New

  13. Study of deformed quasi-periodic Fibonacci two dimensional photonic crystals

    International Nuclear Information System (INIS)

    Abdelaziz, K Ben; Bouazzi, Y; Kanzari, M

    2015-01-01

    Quasi-periodic photonic crystals are not periodic structures. These structures are generally obtained by the arrangement of layers according to a recursive rule. Properties of these structures make more attention the researchers especially in the case when applying defects. So, photonic crystals with defects present localized modes in the band gap leading to many potential applications such light localization.The objective of this work is to study by simulation the effect of the global deformation introduced in 2D quasiperiodic photonic crystals. Deformation was introduced by applying a power law, so that the coordinates y of the deformed object were determined through the coordinates x of the non-deformed structure in accordance with the following rule: y = x 1+k . Here k is the coefficient defining the deformation. Therefore, the objective is to study the effect of this deformation on the optical properties of 2D quasiperiodic photonic crystals, constructed by Fibonacci generation. An omnidirectional mirror was obtained for optimization Fibonacci iteration in a part of visible spectra. (paper)

  14. A study of the inferred interplanetary magnetic field polarity periodicities

    International Nuclear Information System (INIS)

    Xanthakis, J.; Tritakis, V.P.; Zerefos, Ch.

    1981-01-01

    A detailed Power Spectrum Analysis applied on the daily polarities of the inferred interplanetary magnetic field, published by Svalgaard, has pointed out that the main periodicity apparent in these data is 27-28 days, which suggests a recurrency of a 2-sector structure. There is also a secondary periodicity of 13-14 days which mainly appears in the yers of the descending branch of the solar cycle and superimposes on the 2-sector structure, transforming it into a 4-sector structure. A strict statistical study of the correlation between the predominant polarity of the interplanetary magnetic field and the heliographic latitude of the Earth, also known as the Rosenberg-Coleman effect, pointed out that perhaps there is a faint correspondence between these two elements, but one cannot speak of a systematic effect. (Auth.)

  15. Menstrual cups and sanitary pads to reduce school attrition, and sexually transmitted and reproductive tract infections: a cluster randomised controlled feasibility study in rural Western Kenya.

    Science.gov (United States)

    Phillips-Howard, Penelope A; Nyothach, Elizabeth; Ter Kuile, Feiko O; Omoto, Jackton; Wang, Duolao; Zeh, Clement; Onyango, Clayton; Mason, Linda; Alexander, Kelly T; Odhiambo, Frank O; Eleveld, Alie; Mohammed, Aisha; van Eijk, Anna M; Edwards, Rhiannon Tudor; Vulule, John; Faragher, Brian; Laserson, Kayla F

    2016-11-23

    Conduct a feasibility study on the effect of menstrual hygiene on schoolgirls' school and health (reproductive/sexual) outcomes. 3-arm single-site open cluster randomised controlled pilot study. 30 primary schools in rural western Kenya, within a Health and Demographic Surveillance System. Primary schoolgirls 14-16 years, experienced 3 menses, no precluding disability, and resident in the study area. 1 insertable menstrual cup, or monthly sanitary pads, against 'usual practice' control. All participants received puberty education preintervention, and hand wash soap during intervention. Schools received hand wash soap. Primary: school attrition (drop-out, absence); secondary: sexually transmitted infection (STI) (Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoea), reproductive tract infection (RTI) (bacterial vaginosis, Candida albicans); safety: toxic shock syndrome, vaginal Staphylococcus aureus. Of 751 girls enrolled 644 were followed-up for a median of 10.9 months. Cups or pads did not reduce school dropout risk (control=8.0%, cups=11.2%, pads=10.2%). Self-reported absence was rarely reported and not assessable. Prevalence of STIs in the end-of-study survey among controls was 7.7% versus 4.2% in the cups arm (adjusted prevalence ratio (aPR) 0.48, 0.24 to 0.96, p=0.039), 4.5% with pads (aPR=0.62; 0.37 to 1.03, p=0.063), and 4.3% with cups and pads pooled (aPR=0.54, 0.34 to 0.87, p=0.012). RTI prevalence was 21.5%, 28.5% and 26.9% among cup, pad and control arms, 71% of which were bacterial vaginosis, with a prevalence of 14.6%, 19.8% and 20.5%, per arm, respectively. Bacterial vaginosis was less prevalent in the cups (12.9%) compared with pads (20.3%, aPR=0.65, 0.44 to 0.97, p=0.034) and control (19.2%, aPR=0.67, 0.43 to 1.04, p=0.075) arm girls enrolled for 9 months or longer. No adverse events were identified. Provision of menstrual cups and sanitary pads for ∼1 school-year was associated with a lower STI risk, and cups with a lower

  16. Measuring viability of pacs during reform period in Maharashtra: A case study

    OpenAIRE

    Shah, Deepak

    2007-01-01

    The study showed a reduction in the operational efficiency of the selected PACS during the post-economic reform period as against the pre-economic reform period. The operational efficiency was measured in respect of various liquidity ratio, profitability ratios and financial leverage ratios. Not only the selected societies showed a decline in their current ratio, rate of return on assets, return on owner’s equity and Marginal Efficiency of Capital (MEC) but also showed higher dependency on le...

  17. Weight-loss study in African-American Women: lessons learned from project take HEED and future, technologically enhanced directions.

    Science.gov (United States)

    Murphy, Pamala J; Williams, Roger L

    2013-01-01

    African-American women are more overweight and have greater difficulty maintaining weight loss than do Caucasian women. Evidence suggests that African-American women are more successful with culturally tailored weight-loss programs. Begun in 2005, an 18-month randomized clinical trial, Project Take HEED (Healthy Eating and Exercise Decisions), culturally adapted an evidence-based dietary approach and exercise program to fit the female African-American population in an attempt to improve program attrition rates. The study was conducted with 223 African-American women (120 women in the experimental group; 103 controls), age 35 to 65 years, with a body mass index of 30 kg/m(2) or higher. The experimental group received education and instruction at 24 group sessions and were asked to record their daily food intake and physical activity. Cultural adaptation included social and spiritual components. Controls received usual care (referral to a dietitian). After 18 months, Project Take HEED demonstrated the following outcomes: ATTRITION: the treatment group consisted of 12 African-American women at the end of month 18-(an attrition rate of 87%). (It had been 70% at the end of month 15.)FACTORS CONTRIBUTING TO ATTRITION INCLUDED: caregiver responsibilities, transportation difficulties, work schedules, and others. Those clients that did remain, however, provided the impetus for our next study. The remaining participants had, by and large, begun the study as being low in self-efficacy regarding weight loss and weight loss maintenance. Initial Findings: The high self-efficacy that some women had at the beginning of the intervention did not translate into the desired behavior change. The inverse relationship seen in this study suggests that treatments that improve participants' self-efficacy may result in greater weight loss. New Directions: A new study, commencing in 2013, will use at-home Web-based and virtual reality technology (avatars) in an attempt to enhance client

  18. A study of 3-dimensionally periodic carbon nanostructures

    Science.gov (United States)

    Yin, Ming; Bleiweiss, Michael; Amirzadeh, Jafar; Datta, Timir; Arammash, Fouzi

    2012-02-01

    Electronic structures with intricate periodic 3-dimensional arrangements at the submicron scale were investigated. These may be fabricated using artificial porous opal substrates as the templates in which the targeted conducting medium is introduced. In the past these materials were reported to show interesting electronic behaviors. [Michael Bleiweiss, et al ``Localization and Related Phenomena in Multiply Connected Nanostructured,'' BAPS, Z30.011, Nanostructured Materials Session, March 2001, Seattle]. Several materials were studied in particular disordered carbon which has been reported to show quantum transport including fractional hall steps. The results of these measurements, including the observation of localization phenomena, will be discussed. Comparisons will be made with literature data.

  19. Gifted Students in Transition: A Grounded Theory Study

    Science.gov (United States)

    Meadows, Jodi J.

    2017-01-01

    Gifted students in transition to college may be at risk for underachievement, difficult transition, or even attrition. Giftedness by itself is not always sufficient for academic success in college. The purpose of this grounded theory study was to construct a theory regarding the process of transition to college for high-achieving gifted high…

  20. The effect of targeted treatment on people with patellofemoral pain: a pragmatic, randomised controlled feasibility study.

    Science.gov (United States)

    Drew, Benjamin T; Conaghan, Philip G; Smith, Toby O; Selfe, James; Redmond, Anthony C

    2017-08-04

    Targeted treatment, matched according to specific clinical criteria e.g. hip muscle weakness, may result in better outcomes for people with patellofemoral pain (PFP). However, to ensure the success of future trials, a number of questions on the feasibility of a targeted treatment need clarification. The aim of the study was to explore the feasibility of matched treatment (MT) compared to usual care (UC) management for a subgroup of people with PFP determined to have hip weakness and to explore the mechanism of effect for hip strengthening. In a pragmatic, randomised controlled feasibility study, 24 participants with PFP (58% female; mean age 29 years) were randomly allocated to receive either MT aimed specifically at hip strengthening, or UC over an eight-week period. The primary outcomes were feasibility outcomes, which included rates of adherence, attrition, eligibility, missing data and treatment efficacy. Secondary outcomes focused on the mechanistic outcomes of the intervention, which included hip kinematics. Conversion to consent (100%), missing data (0%), attrition rate (8%) and adherence to both treatment and appointments (>90%) were deemed successful endpoints. The analysis of treatment efficacy showed that the MT group reported a greater improvement for the Global Rating of Change Scale (62% vs. 9%) and the Anterior Knee Pain Scale (-5.23 vs. 1.18) but no between-group differences for either average or worst pain. Mechanistic outcomes showed a greatest reduction in peak hip internal rotation angle for the MT group (13.1% vs. -2.7%). This feasibility study indicates that a definitive randomised controlled trial investigating a targeted treatment approach is achievable. Findings suggest the mechanism of effect of hip strengthening may be to influence kinematic changes in hip function in the transverse plane. This study was registered retrospectively. ISRCTN74560952 . Registration date: 2017-02-06.

  1. Are Seminar Periods Supportive of the Professional Development of Social Studies Teachers?

    Science.gov (United States)

    Demir, Selçuk Besir; Dogan, Soner; Atasoy, Turgay

    2016-01-01

    The purpose of this study is to determine the efficiency of the seminar periods intended for contributing to the professional development of social studies teachers based on their own perspectives. This study adopts a qualitative approach and is carried out in the form of a case study. Among the purposeful sampling methods, the criteria sample…

  2. Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lin Yimin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: linyimin_2001@yahoo.com.cn; Lu Jian [LASMIS, University of Technology of Troyes, 10000 Troyes (France); Wang Liping [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Tao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China)]. E-mail: qjxue@ns.lzb.ac.cn

    2006-12-15

    A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Vickers hardness tester and UMT-2MT tribometer. The results show that the plasma nitriding of AISI 321 steel can be enhanced considerably by means of SMAT process before nitriding, and a much thicker nitrogen diffusion layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples. In addition, the wear resistance and load capacity of the nitrided layers on the SMAT samples was much higher than that of the un-SMAT samples due to the thicker S phase case and the gradient nitrogen diffusion layer.

  3. Evolution of periodicity in periodical cicadas.

    Science.gov (United States)

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  4. Dried Blood Spot Collection of Health Biomarkers to Maximize Participation in Population Studies

    Science.gov (United States)

    Ostler, Michael W.; Porter, James H.; Buxton, Orfeu M.

    2014-01-01

    Biomarkers are directly-measured biological indicators of disease, health, exposures, or other biological information. In population and social sciences, biomarkers need to be easy to obtain, transport, and analyze. Dried Blood Spots meet this need, and can be collected in the field with high response rates. These elements are particularly important in longitudinal study designs including interventions where attrition is critical to avoid, and high response rates improve the interpretation of results. Dried Blood Spot sample collection is simple, quick, relatively painless, less invasive then venipuncture, and requires minimal field storage requirements (i.e. samples do not need to be immediately frozen and can be stored for a long period of time in a stable freezer environment before assay). The samples can be analyzed for a variety of different analytes, including cholesterol, C-reactive protein, glycosylated hemoglobin, numerous cytokines, and other analytes, as well as provide genetic material. DBS collection is depicted as employed in several recent studies. PMID:24513728

  5. Regression periods in infancy: a case study from Catalonia.

    Science.gov (United States)

    Sadurní, Marta; Rostan, Carlos

    2002-05-01

    Based on Rijt-Plooij and Plooij's (1992) research on emergence of regression periods in the first two years of life, the presence of such periods in a group of 18 babies (10 boys and 8 girls, aged between 3 weeks and 14 months) from a Catalonian population was analyzed. The measurements were a questionnaire filled in by the infants' mothers, a semi-structured weekly tape-recorded interview, and observations in their homes. The procedure and the instruments used in the project follow those proposed by Rijt-Plooij and Plooij. Our results confirm the existence of the regression periods in the first year of children's life. Inter-coder agreement for trained coders was 78.2% and within-coder agreement was 90.1%. In the discussion, the possible meaning and relevance of regression periods in order to understand development from a psychobiological and social framework is commented upon.

  6. What predicts the mobility of elementary schoolleaders? An analysis of longitudinal data in Colorado

    Directory of Open Access Journals (Sweden)

    Motoko Akiba

    2004-04-01

    Full Text Available While many studies have reported the predictors of teacher attrition, we know little about what predicts the attrition of school leaders. Using the Colorado state data on elementary school principals’ and assistant principals’ career paths from 1999 to 2001 and school achievement-level data, we addressed two research questions: 1 How do the age-specific attrition rates differ by gender and race? and 2 What other conditional factors are associated with the attrition of school leaders? We found that female and minority groups generally had higher attrition rates at age 40 or younger and at age 56 or older than male and non-minority groups. Our data also indicated that school size and salary increase were associated with the attrition of both male and female leaders. Large schools were more likely to have higher rates of school leader attrition, and the leaders who expected relatively higher salary increases by transferring were more likely to leave their schools. Lower school achievement predicted higher attrition of female leaders only. These findings have important implications for policy-makers when they plan and implement strategies for preventing high attrition rates of school leaders.

  7. A CLINICAL AND NEUROELECTROPHYSIOLO-GICAL STUDY OF HYPERKALEMIC PERIODIC PARALYSIS

    Institute of Scientific and Technical Information of China (English)

    高秀贤; 汤晓芙; 杜华; 李本红

    1995-01-01

    A case of atypical hyperkalemic periodic paralysis is reported. The diagnosis was confirmed by hyperkalemic test, cold water test, and differentiation of attack period and rest period by the measurement of motor nerve conduction amplitude. Etio-pathology of this disease is discussed from the view of neuroelec-trophysiology.

  8. Periodic waves in nonlinear metamaterials

    International Nuclear Information System (INIS)

    Liu, Wen-Jun; Xiao, Jing-Hua; Yan, Jie-Yun; Tian, Bo

    2012-01-01

    Periodic waves are presented in this Letter. With symbolic computation, equations for monochromatic waves are studied, and analytic periodic waves are obtained. Factors affecting properties of periodic waves are analyzed. Nonlinear metamaterials, with the continuous distribution of the dielectric permittivity obtained, are different from the ones with the discrete distribution. -- Highlights: ► Equations for the monochromatic waves in transverse magnetic polarization have been studied. ► Analytic periodic waves for the equations have been obtained. ► Periodic waves are theoretically presented and studied in the nonlinear metamaterials.

  9. Bounded and Periodic Solutions of Semilinear Impulsive Periodic System on Banach Spaces

    Directory of Open Access Journals (Sweden)

    Wei W

    2008-01-01

    Full Text Available Abstract A class of semilinear impulsive periodic system on Banach spaces is considered. First, we introduce the -periodic PC-mild solution of semilinear impulsive periodic system. By virtue of Gronwall lemma with impulse, the estimate on the PC-mild solutions is derived. The continuity and compactness of the new constructed Poincaré operator determined by impulsive evolution operator corresponding to homogenous linear impulsive periodic system are shown. This allows us to apply Horn's fixed-point theorem to prove the existence of -periodic PC-mild solutions when PC-mild solutions are ultimate bounded. This extends the study on periodic solutions of periodic system without impulse to periodic system with impulse on general Banach spaces. At last, an example is given for demonstration.

  10. Retention: An Inductive Study of Representative Student Groups at Middlesex County College.

    Science.gov (United States)

    Harrower, Gordon, Jr.; And Others

    This five-part report describes a study conducted by Middlesex County College (MCC) to examine the problems and experiences of various segments of its student body and to determine, on the basis of this examination, factors that aggravate student/college interaction and increase student attrition. Part I details study procedures, which involved a…

  11. Nanocrystalline-grained tungsten prepared by surface mechanical attrition treatment: Microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Guo, Hong-Yan; Xia, Min; Wu, Zheng-Tao; Chan, Lap-Chung; Dai, Yong; Wang, Kun; Yan, Qing-Zhi; He, Man-Chao; Ge, Chang-Chun; Lu, Jian

    2016-01-01

    A nanostructured surface layer was fabricated on commercial pure tungsten using the method of surface mechanical attrition treatment (SMAT). The microstructure evolution of the surface layer was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and its formation mechanism was discussed as well. Both refinement and elongation of the brittle W grains were confirmed. The elongated SMATed W was heavily strained, the maximum value of the strain at the grain boundaries reaches as high as 3–5%. Dislocation density in the SMATed W nanograins was found to be 5 × 10 12  cm −2 . The formation of the nanograins in the top surface layer of the W was ascribed to the extremely high strain and strain rate, as well as the multidirectional repetitive loading. Bending strength of commercial W could be improved from 825 MPa to 1850 MPa by SMAT process. Microhardness results indicated the strain range in SMATed W can reach up to 220 μm beneath the top surface. The notched Charpy testing results demonstrated that SMATed W possess higher ductility than that of commercial W. The top surface of the W plates with and without SMATe processing possesses residual compressive stress of about −881 MPa and −234 MPa in y direction, and −872 MPa and −879 MPa in x direction respectively. The improvement of toughness (DBTT shift) of SMATed W may be the synergistic effect of residual compressive stress, dislocation density improvement and microstructure refinement induced by SMAT processing. SMAT processing could be a complementary method to further decrease the DBTT value of tungsten based materials.

  12. Nanocrystalline-grained tungsten prepared by surface mechanical attrition treatment: Microstructure and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Hong-Yan [State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083 (China); Institute of Nuclear Materials, University of Science & Technology Beijing, Beijing 100083 (China); Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tae Chee Avenue Kowloon, Hong Kong 999077 (China); Xia, Min, E-mail: xmdsg@ustb.edu.cn [Institute of Nuclear Materials, University of Science & Technology Beijing, Beijing 100083 (China); Wu, Zheng-Tao [College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Chan, Lap-Chung [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tae Chee Avenue Kowloon, Hong Kong 999077 (China); Dai, Yong; Wang, Kun [Laboratory for Nuclear Materials, Paul Scherrer Institut, 5323 Villigen PSI (Switzerland); Yan, Qing-Zhi [Institute of Nuclear Materials, University of Science & Technology Beijing, Beijing 100083 (China); He, Man-Chao [State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083 (China); Ge, Chang-Chun, E-mail: ccge@mater.ustb.edu.cn [Institute of Nuclear Materials, University of Science & Technology Beijing, Beijing 100083 (China); Lu, Jian, E-mail: jianlu@cityu.edu.hk [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tae Chee Avenue Kowloon, Hong Kong 999077 (China)

    2016-11-15

    A nanostructured surface layer was fabricated on commercial pure tungsten using the method of surface mechanical attrition treatment (SMAT). The microstructure evolution of the surface layer was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and its formation mechanism was discussed as well. Both refinement and elongation of the brittle W grains were confirmed. The elongated SMATed W was heavily strained, the maximum value of the strain at the grain boundaries reaches as high as 3–5%. Dislocation density in the SMATed W nanograins was found to be 5 × 10{sup 12} cm{sup −2}. The formation of the nanograins in the top surface layer of the W was ascribed to the extremely high strain and strain rate, as well as the multidirectional repetitive loading. Bending strength of commercial W could be improved from 825 MPa to 1850 MPa by SMAT process. Microhardness results indicated the strain range in SMATed W can reach up to 220 μm beneath the top surface. The notched Charpy testing results demonstrated that SMATed W possess higher ductility than that of commercial W. The top surface of the W plates with and without SMATe processing possesses residual compressive stress of about −881 MPa and −234 MPa in y direction, and −872 MPa and −879 MPa in x direction respectively. The improvement of toughness (DBTT shift) of SMATed W may be the synergistic effect of residual compressive stress, dislocation density improvement and microstructure refinement induced by SMAT processing. SMAT processing could be a complementary method to further decrease the DBTT value of tungsten based materials.

  13. Self-consistent simulation studies of periodically focused intense charged-particle beams

    International Nuclear Information System (INIS)

    Chen, C.; Jameson, R.A.

    1995-01-01

    A self-consistent two-dimensional model is used to investigate intense charged-particle beam propagation through a periodic solenoidal focusing channel, particularly in the regime in which there is a mismatch between the beam and the focusing channel. The present self-consistent studies confirm that mismatched beams exhibit nonlinear resonances and chaotic behavior in the envelope evolution, as predicted by an earlier envelope analysis [C. Chen and R. C. Davidson, Phys. Rev. Lett. 72, 2195 (1994)]. Transient effects due to emittance growth are studied, and halo formation is investigated. The halo size is estimated. The halo characteristics for a periodic focusing channel are found to be qualitatively the same as those for a uniform focusing channel. A threshold condition is obtained numerically for halo formation in mismatched beams in a uniform focusing channel, which indicates that relative envelope mismatch must be kept well below 20% to prevent space-charge-dominated beams from developing halos

  14. Comparison of Periodized and Non-Periodized Resistance Training on Maximal Strength: A Meta-Analysis.

    Science.gov (United States)

    Williams, Tyler D; Tolusso, Danilo V; Fedewa, Michael V; Esco, Michael R

    2017-10-01

    Periodization is a logical method of organizing training into sequential phases and cyclical time periods in order to increase the potential for achieving specific performance goals while minimizing the potential for overtraining. Periodized resistance training plans are proposed to be superior to non-periodized training plans for enhancing maximal strength. The primary aim of this study was to examine the previous literature comparing periodized resistance training plans to non-periodized resistance training plans and determine a quantitative estimate of effect on maximal strength. All studies included in the meta-analysis met the following inclusion criteria: (1) peer-reviewed publication; (2) published in English; (3) comparison of a periodized resistance training group to a non-periodized resistance training group; (4) maximal strength measured by 1-repetition maximum (1RM) squat, bench press, or leg press. Data were extracted and independently coded by two authors. Random-effects models were used to aggregate a mean effect size (ES), 95% confidence intervals (CIs) and potential moderators. The cumulative results of 81 effects gathered from 18 studies published between 1988 and 2015 indicated that the magnitude of improvement in 1RM following periodized resistance training was greater than non-periodized resistance training (ES = 0.43, 95% CI 0.27-0.58; P training status (β = -0.59; P = 0.0305), study length (β = 0.03; P = 0.0067), and training frequency (β = 0.46; P = 0.0123) were associated with a change in 1RM. These results indicate that undulating programs were more favorable for strength gains. Improvements in 1RM were greater among untrained participants. Additionally, higher training frequency and longer study length were associated with larger improvements in 1RM. These results suggest that periodized resistance training plans have a moderate effect on 1RM compared to non-periodized training plans. Variation in training stimuli

  15. Reflections on Teaching Periodic Table Concepts: A Case Study of Selected Schools in South Africa

    Science.gov (United States)

    Mokiwa, Hamza Omari

    2017-01-01

    The Periodic Table of Elements is central to the study of modern Physics and Chemistry. It is however, considered by teachers as difficult to teach. This paper reports on a case study exploring reflections on teaching periodic table concepts in five secondary schools from South Africa. Qualitative methodology of interviews and document analysis…

  16. Ready for University? A Cross-National Study of Students' Perceived Preparedness for University

    Science.gov (United States)

    Jansen, Ellen P. W. A.; van der Meer, Jacques

    2012-01-01

    Students' preparedness for higher education is seen as one of the main factors affecting first-year attrition or study success. In this paper we report on a cross-national study in which students' preparedness for university was measured "before" students commenced their study at a university in New Zealand or in the Netherlands. This…

  17. Demokrasi Di Malaysia: Studi Perbandingan Periode Pemerintahan Tiga Perdana Menteri Malaysia

    OpenAIRE

    Fauzi, Mohammad

    2015-01-01

    This study aimed to compare the historical descriptive-interpretative effect general election implementation and socio-economic and cultural conditions of democracy and democratic process in Malaysia during the government period of Tunku Abdul Rahman to Mahathir Mohamad. The research based on the secondary data study-method. Based on the research, the general election implementation and socio-economic and cultural condition do not significant effect on democracy and the democratic process in ...

  18. A STUDY OF THE VARIED AETIOLOGY AND CLINICAL PRESENTATION OF NEW ONSET SEIZURES IN POSTPARTUM PERIOD

    Directory of Open Access Journals (Sweden)

    Ravindra Kumar Sudarsi

    2016-08-01

    Full Text Available BACKGROUND Seizures in the postpartum period are the major cause of mortality and morbidity. A variety of neurological disorders causing seizures may be encountered during pregnancy and puerperium. These disorders may be unrelated to pregnancy (e.g. Meningitis or peculiar to pregnancy (e.g. Eclampsia or. Pregnancy may affect the course of the pre-existing neurological disorders such as epilepsy. So, keeping in mind the varied aetiology of postpartum seizures and its response to appropriate treatment, our study has been conducted to find out the most common causes in our setup to guide the optimal therapy. AIM OF THE STUDY To study the varied aetiology and clinical presentation of new onset seizures in the postpartum period over a period of two years. MATERIALS AND METHODS 50 patients who developed first episode of seizures in postpartum period (that is after delivery to 6 weeks admitted to Osmania General Hospital on random selection. All women complaining of new onset seizure with in postpartum period up to 6 weeks. All those women who are known epileptics and who had seizures in the antenatal period were excluded from the study. The selected patients were studied in detail with history and physical examination. RESULTS Different causes for first episode of seizures in postpartum period are enlisted here. Cavernous sinus thrombosis in 17 patients, late postpartum eclampsia accounted for 13 patients, intracranial haemorrhage in 6 patients, ischaemic stroke in 5 patients, posterior reversible encephalopathy syndrome in 4 patients, CNS infections in 6 patients, glioma in 1 patient, viral hepatitis in one patient, idiopathic in 3 patients. CONCLUSIONS Cavernous sinus thrombosis and late postpartum eclampsia constitute the major aetiology of first onset of seizes occurring in the postpartum period.

  19. Study of periodically excited bubbly jets by PIV and double optical sensors

    International Nuclear Information System (INIS)

    Milenkovic, Rade; Sigg, Beat; Yadigaroglu, George

    2005-01-01

    Interactions between large coherent structures and bubbles in two-phase flow can be systematically observed in a periodically excited bubbly jet. Controlled excitation at fixed frequency causes large eddy structures to develop at regular intervals. Thus, interactions between large vortices and bubbles can be studied with PIV and double optical sensors (DOS) using phase-averaging techniques. A number of results on the time and space dependence of velocities and void fractions are presented revealing physical interactions between the liquid flow field and bubble movement as well as feedbacks from bubble agglomeration on the development of flow structures. A clear indication of bubble trapping inside the vortex ring is the generation of a bubble ring that travels with the same velocity as the vortex ring. The DOS results indicate clustering of the bubbles in coherent vortex structures, with a periodic variation of void fraction during the excitation period

  20. Study of periodically excited bubbly jets by PIV and double optical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Milenkovic, Rade [Laboratorium fuer Thermalhydraulics PSI, Paul Scherrer Institut, OVGA 415, CH-5232 Villigen PSI (Switzerland)]. E-mail: rade.milenkovic@psi.ch; Sigg, Beat [Laboratorium fuer Kerntechnik, ETHZ, ETH Zentrum CLT, CH-8092 Zurich (Switzerland); Yadigaroglu, George [Laboratorium fuer Kerntechnik, ETHZ, ETH Zentrum CLT, CH-8092 Zurich (Switzerland)

    2005-12-15

    Interactions between large coherent structures and bubbles in two-phase flow can be systematically observed in a periodically excited bubbly jet. Controlled excitation at fixed frequency causes large eddy structures to develop at regular intervals. Thus, interactions between large vortices and bubbles can be studied with PIV and double optical sensors (DOS) using phase-averaging techniques. A number of results on the time and space dependence of velocities and void fractions are presented revealing physical interactions between the liquid flow field and bubble movement as well as feedbacks from bubble agglomeration on the development of flow structures. A clear indication of bubble trapping inside the vortex ring is the generation of a bubble ring that travels with the same velocity as the vortex ring. The DOS results indicate clustering of the bubbles in coherent vortex structures, with a periodic variation of void fraction during the excitation period.

  1. Entering University Studies: Identifying Enabling Factors for a Successful Transition from School to University

    Science.gov (United States)

    McGhie, Venicia

    2017-01-01

    The South African higher education sector is faced with high attrition and low retention rates. Studies conducted by the Council on Higher Education in South Africa have found that 50% of black students who access university study drop out, and the majority of dropouts occurred in the first year of study. While these studies revealed what the…

  2. Split-field FDTD method for oblique incidence study of periodic dispersive metallic structures.

    Science.gov (United States)

    Baida, F I; Belkhir, A

    2009-08-15

    The study of periodic structures illuminated by a normally incident plane wave is a simple task that can be numerically simulated by the finite-difference time-domain (FDTD) method. On the contrary, for off-normal incidence, a widely modified algorithm must be developed in order to bypass the frequency dependence appearing in the periodic boundary conditions. After recently implementing this FDTD algorithm for pure dielectric materials, we here extend it to the study of metallic structures where dispersion can be described by analytical models. The accuracy of our code is demonstrated through comparisons with already-published results in the case of 1D and 3D structures.

  3. Depositional environments of the Hart coal zone (Paleocene), Willow Bunch Coalfield, southern Saskatchewan, Canada from petrographic, palynological, paleobotanical, mineral and trace element studies

    Energy Technology Data Exchange (ETDEWEB)

    Potter, J.; Beaton, A.P.; McDougall, W.J.; Nambudiri, E.M.V.; Vigrass, L.W. (University of Regina, SK (Canada). Energy Research Unit)

    1991-12-01

    Coal petrology, palynology, paleobotany and mineralogy of the Hart coal indicate deposition under wet, warm-temperate to subtropical climatic conditions in low-lying backswamps with fluvial channels and locally ponded areas. The coal is dominated by mixed xylitic/attrital lithotypes and by huminite macerals with secondary inertinite macerals and minor liptinite macerals. Good correlation exists between lithotypes and maceral composition. Local and vertical variations in proportions of huminites and inertinites reflect frequent fluctuations in water levels, periodic flooding, desiccation and burning of the peat. Swamps were dominated by {ital Glyptostrobus-Taxodium} forest with {ital Betula-Myrica-Alnus} communities and, locally {ital Laevigatosporites}, which are the dominant contributors to the xylite-rich lithotypes. Attrital lithotypes with abundant {ital Pandanus}, {ital Typha} and {ital Azolla} are consistent with wetter areas of a fluvial environment, including ponds and channels. Trace elements Cr, Cu, Mo, Ni, Si, Ti, U, Se, V, W, K and Th, typically associated with syngenetic minerals kaolinite, calcite and quartz, may have a volcanic source. High concentrations of Na, Ba and Ca found in organic complexes are of secondary origin and probably originate in deep source brines rather than marine surface waters. 55 refs., 11 figs., 5 tabs.

  4. The Physician Attrition Crisis: A Cross-Sectional Survey of the Risk Factors for Reduced Job Satisfaction Among US Surgeons.

    Science.gov (United States)

    Jackson, Theresa N; Pearcy, Chris P; Khorgami, Zhamak; Agrawal, Vaidehi; Taubman, Kevin E; Truitt, Michael S

    2018-05-01

    A physician shortage is on the horizon, and surgeons are particularly vulnerable due to attrition. Reduced job satisfaction leads to increased job turnover and earlier retirement. The purpose of this study is to delineate the risk factors that contribute to reduced job satisfaction. A cross-sectional survey of US surgeons was conducted from September 2016 to May 2017. Screening for job satisfaction was performed using the abridged Job in General scale. Respondents were grouped into more and less satisfied using the median split. Twenty-five potential risk factors were examined that included demographic, occupational, psychological, wellness, and work-environment variables. Overall, 993 respondents were grouped into more satisfied (n = 502) and less satisfied (n = 491) cohorts. Of the demographic variables, female gender and younger age were associated with decreased job satisfaction (p = 0.003 and p = 0.008). Most occupational variables (specialty, experience, academics, practice size, payment model) were not significant. However, increased average hours worked correlated with less satisfaction (p = 0.008). Posttraumatic stress disorder, burnout, wellness, all eight work-environment variables, and unhappiness with career choice were linked to reduced job satisfaction (p = 0.001). A surgeon shortage has serious implications for health care. Job satisfaction is associated with physician retention. Our results suggest women and younger surgeons may be at increased risk for job dissatisfaction. Targeted work-environment interventions to reduce work-hours, improve hospital culture, and provide adequate financial reimbursement may promote job satisfaction and wellness.

  5. Applying Data-mining techniques to study drought periods in Spain

    Science.gov (United States)

    Belda, F.; Penades, M. C.

    2010-09-01

    Data-mining is a technique that it can be used to interact with large databases and to help in the discovery relations between parameters by extracting information from massive and multiple data archives. Drought affects many economic and social sectors, from agricultural to transportation, going through urban water deficit and the development of modern industries. With these problems and drought geographical and temporal distribution it's difficult to find a single definition of drought. Improving the understanding of the knowledge of climatic index is necessary to reduce the impacts of drought and to facilitate quick decisions regarding this problem. The main objective is to analyze drought periods from 1950 to 2009 in Spain. We use several kinds of information, different formats, sources and transmission mode. We use satellite-based Vegetation Index, dryness index for several temporal periods. We use daily and monthly precipitation and temperature data and soil moisture data from numerical weather model. We calculate mainly Standardized Precipitation Index (SPI) that it has been used amply in the bibliography. We use OLAP-Mining techniques to discovery of association rules between remote-sensing, numerical weather model and climatic index. Time series Data- Mining techniques organize data as a sequence of events, with each event having a time of recurrence, to cluster the data into groups of records or cluster with similar characteristics. Prior climatological classification is necessary if we want to study drought periods over all Spain.

  6. Multicultural Benefits and Challenges for International Students During Period of Their Study: Case Study in Malaysia

    OpenAIRE

    Ramli Bin Basri, Baharak Talebloo

    2015-01-01

    Current researches on internationalization claim €œstudying overseas€ as a set of potential that assist the augmentation of €œglobalization€. This article presents the Multicultural Benefits and challenges for International Students during Period of their Study in university Putra Malaysia. Qualitative method and convenience sampling was applied. Semi-structured interview and in depth interviews were conducted on 20 postgraduate students from various fields of study. The result of study sho...

  7. An Exploratory Study of Group Therapy for Sexually Abused Adolescents and Nonoffending Guardians

    Science.gov (United States)

    Smith, Amanda P.; Kelly, Adrian B.

    2008-01-01

    Adolescent survivors of sexual abuse frequently report severe trauma, depression, anxiety, and low self-esteem. While cognitive-behavioral group interventions show promise, interpreting efficacy is problematic due to commonly high attrition. This article reports promising exploratory study findings relating to a 12-week multimodal abuse-specific…

  8. Utilization of critical periods during development to study the effects of low levels of environmental agents

    International Nuclear Information System (INIS)

    Russell, L.B.

    1981-01-01

    This chapter shows how careful definition of critical periods in the development of selected characters can result in experimental systems that may be highly useful in studying risk at low levels of exposure. Presents 3 systems that utilize critical periods to study low-level effects: 1) cell kinetics as an indicator of nervous-system maldevelopment; 2) oocyte depletion; and 3) homeotic shifts in the skeleton. Discusses application of the sensitive systems to the testing of chemicals and the role of sensitive stages in estimating risk. Suggests that tests such as the 3 discussed in this paper, which are developed with strict attention to specific critical periods, can provide rapid and sensitive means for revealing whether an agent is capable of causing developmental interference. Concludes that epidemiological investigations can lose much of their value unless critical periods are known for the endpoints being studied

  9. Influence of olive oil on alveolar bone response during orthodontic retention period: rabbit model study.

    Science.gov (United States)

    Al-Hamdany, Afrah K; Al-Khatib, Ali R; Al-Sadi, Hafidh I

    2017-08-01

    This study attempted to evaluate clinically and histologically the effects of olive oil (Ol) consumption on orthodontic relapse after the retention period. Thirty apparently healthy female albino rabbits, weight more than 1000 g each was used in this study. The animals were grouped randomly into six groups of five animals each: two control and four experimental groups. In control groups, the relapse was estimated either at zero day, or at the end of the fourth week after orthodontic retention period. In the experimental groups, the animals' groups received Ol, 7.7, or 15.4 ml/kg b.w. per day during the orthodontic retention period. The relapse was estimated either at zero day, or at the end of the fourth week after orthodontic retention period for each concentration. Modified fixed orthodontic appliances were attached to the rabbits' lower central incisors. Each rabbit received orthodontic intervention for one week, followed by six weeks retention period. At the end of the experiments, the clinical and histological investigations were conducted. Data analyses were performed at the level of p orthodontic retention period, especially at 15.4 ml/kg b.w. per day concentration, clinically reduced orthodontic relapse on rabbit model. Histologically, Ol increased osteoblasts and osteocytes counts and the relative amount of bone mineralization of connective tissue layer forming alveolar bone (AB) at the end of four weeks after the orthodontic retention period.

  10. The study of the evolution of squares in 3 periods of Safavid, Qajar ...

    African Journals Online (AJOL)

    The study of the evolution of squares in 3 periods of Safavid, Qajar and Pahlavi with historical – evolutionary and form approach (Isfahan and Tehran styles) case study of Naqshe Jahan square in Isfahan, Ganjalikhan square in Kerman, Sabze Meydan and Toop.

  11. POLITICAL MONETARY CYCLES IN COALITION AND SINGLE PARTY GOVERNMENT PERIODS: A CASE STUDY ON TURKEY

    Directory of Open Access Journals (Sweden)

    AHMET EMRAH TAYYAR

    2017-12-01

    Full Text Available According to the theory of political monetary cycles, the government manipulates monetary policy during election periods in order to be re-elected. According to the said theory, expansionary monetary policies are implemented before the elections with opportunistic objective, while the contractionary monetary policies are implemented to stabilize the economy immediately after the elections. The use of monetary policy instruments for political purposes depends on the presence of a non-autonomous central bank, flexible exchange rate regime in the country, and the coordination between fiscal and monetary policies. Thus, the changes in the monetary policy indicators in election periods during coalition and single party governments in Turkey between 1990 and 2016 were examined in the present study. The money in circulation (M0, M1 money supply, domestic loans and inflation series were analyzed with the seasonal Box-Jenkins method for the above mentioned periods. Based on the findings of the study, political monetary cycles were not observed during the 1990-2000 coalition governments. It was determined that there were political monetary cycles during the single party government period between 2000 and 2016.Furthermore, although it could be expected that the political monetary cycles would be removed with the liberalization of the Turkish central bank on 25 April 2001, the existence of political monetary cycles during the period of 2000-2016 indicates that central bank independence was not fully achieved in Turkey. Based on another finding of the present study, the lack of political monetary cycles during the coalition government periods could lead to the failure in financing the budget deficit that increase due to political reasons with monetary policies. However, due to the existence of political monetary cycles during the single party government period, it could be argued that politically induced budget deficits changed in consistence with the

  12. Cross-sectional study of anxiety symptoms in students in preexamination period

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    Prateek Yadav

    2017-01-01

    Full Text Available Background: Preexamination period is an exceptionally stressful time for schoolgoing children and adolescents, and the propensity of having anxiety symptoms increases. Aim: This study aimed to assess the presence of anxiety symptoms in students in preexamination period. Materials and Methods: The study was carried on 619 children from Class VIII to XI. All of them were given a structured questionnaire for sociodemographic profile and Screen for Child Anxiety Related Emotional Disorders questionnaire. Association of various variables with presence of anxiety symptoms was assessed. Statistics was analyzed with SPSS version 17.0 software. Results: Totally 170 children (27.5% had anxiety symptoms, similarly the various subgroups had increased frequency compared to the known prevalence in this age group. Age, years spent in the current school, living with parents, presence of domestic stressors, and grade deterioration, all were significantly associated with increased frequency of these symptoms. Similarly, association with various subgroups is described. Conclusion: This study attempts to give evidence of increased anxiety symptoms, during preexamination phase, compared to the reported prevalence in this age group, and thus to address this becomes imperative which will improve their performance and also the mental health preventing distress along with psychological and behavioral problems.

  13. Informing the scale-up of Kenya’s nursing workforce: a mixed methods study of factors affecting pre-service training capacity and production

    Science.gov (United States)

    2014-01-01

    Background Given the global nursing shortage and investments to scale-up the workforce, this study evaluated trends in annual student nurse enrolment, pre-service attrition between enrolment and registration, and factors that influence nurse production in Kenya. Methods This study used a mixed methods approach with data from the Regulatory Human Resources Information System (tracks initial student enrolment through registration) and the Kenya Health Workforce Information System (tracks deployment and demographic information on licensed nurses) for the quantitative analyses and qualitative data from key informant interviews with nurse training institution educators and/or administrators. Trends in annual student nurse enrolment from 1999 to 2010 were analyzed using regulatory and demographic data. To assess pre-service attrition between training enrolment and registration with the nursing council, data for a cohort that enrolled in training from 1999 to 2004 and completed training by 2010 was analyzed. Multivariate logistic regression was used to test for factors that significantly affected attrition. To assess the capacity of nurse training institutions for scale-up, qualitative data was obtained through key informant interviews. Results From 1999 to 2010, 23,350 students enrolled in nurse training in Kenya. While annual new student enrolment doubled between 1999 (1,493) and 2010 (3,030), training institutions reported challenges in their capacity to accommodate the increased numbers. Key factors identified by the nursing faculty included congestion at clinical placement sites, limited clinical mentorship by qualified nurses, challenges with faculty recruitment and retention, and inadequate student housing, transportation and classroom space. Pre-service attrition among the cohort that enrolled between 1999 and 2004 and completed training by 2010 was found to be low (6%). Conclusion To scale-up the nursing workforce in Kenya, concurrent investments in expanding the

  14. Utilization of critical periods during development to study the effects of low levels of environmental agents

    International Nuclear Information System (INIS)

    Russell, L.B.

    1980-01-01

    Careful definition of critical periods in the development of selected characters can result in experimental systems that may be highly useful in studying risk at low levels of exposure. Three examples are presented. Epidemiological investigations can lose much of their value unless critical periods are known for the end points being studied

  15. Kant’s Studies in Ukrainian Philosophy of Soviet Period

    Directory of Open Access Journals (Sweden)

    Vadym Tytarenko

    2018-04-01

    Full Text Available This writing is devoted to the brief review of Immanuel Kant’s philosophy studies and receptions of his philosophical concepts within the Ukrainian philosophy of Soviet period. Such attempt is actually pertinent because nowadays we definitely need to reconsider the soviet philosophical heritage for better understanding the real value of any philosophical conclusions and worldview-concerning statements which were made in the times of soviet ideology hegemony. Additionally, mentioned reconsidering is presently urgent because Ukrainian intellectual culture is now looking for its identity and is trying to identify the stillremaining ideological totalitarian elements which spoil the originality and objectiveness of its products. The present review attempts to identify which totalitarian intentions and prejudices were used to interpret and evaluate the Immanuel Kant’s heritage in the texts written by several selected Ukrainian philosophers of the Soviet period. Nevertheless, it’s obvious that absolutely impossible to avoid talking about Georg Wilhelm Friedrich Hegel’s philosophical position interpretation by the same authors. Kant’s and Hegel’s soviet-Ukrainian interpretations were often connected, because there was a general trend of soviet Marxist history of philosophy to interpret Kant as the “worse” version of Hegel. To fulfill the general image of Kant’s philosophy interpretation in Ukrainian philosophy and its future perspectives, this paper also delivers some common information about the whole historical path of Kant’s interpretations and receptions

  16. Trends in scientific activity addressing transmissible spongiform encephalopathies: a bibliometric study covering the period 1973–2002

    Directory of Open Access Journals (Sweden)

    Iribarren-Maestro Isabel

    2006-10-01

    Full Text Available Abstract Background The purpose of this study is to analyse the trends in scientific research on transmissible spongiform encephalopathies by applying bibliometric tools to the scientific literature published between 1973 and 2002. Methods The data for the study were obtained from Medline database, in order to determine the volume of scientific output in the above period, the countries involved, the type of document and the trends in the subject matters addressed. The period 1973–2002 was divided in three sub-periods. Results We observed a significant growth in scientific production. The percentage of increase is 871.7 from 1973 to 2002. This is more evident since 1991 and particularly in the 1996–2001 period. The countries found to have the highest output were the United States, the United Kingdom, Japan, France and Germany. The evolution in the subject matters was almost constant in the three sub-periods in which the study was divided. In the first and second sub-periods, the subject matters of greatest interest were more general, i.e Nervous system or Nervous system diseases, Creutzfeldt-Jakob disease, Scrapie, and Chemicals and Drugs, but in the last sub-period, some changes were observed because the Prion-related matters had the greatest presence. Collaboration among authors is small from 1973 to 1992, but increases notably in the third sub-period, and also the number of authors and clusters formed. Some of the authors, like Gajdusek or Prusiner, appear in the whole period. Conclusion The study reveals a very high increase in scientific production. It is related also with the beginnings of research on bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease, with the establishment of progressive collaboration relationships and a reflection of public health concerns about this problem.

  17. The Selection of Quantitative Undergraduate Fields of Study: Direct and Indirect Influences.

    Science.gov (United States)

    Ethington, Corinna A.; Wolfle, Lee M.

    In order to increase women's representation among quantitative degrees, Berryman (1985) suggested two strategies: (1) increase women's share of the initial mathematical/scientific pool; or (2) reduce attrition from the pool. However, current research indicates that the decision to enter a quantitative field of study for women is the result of a…

  18. STUDY OF PAEDIATRIC SOLID TUMOURS FOR A PERIOD OF 5 YEARS

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    Basumitra Das

    2017-12-01

    Full Text Available BACKGROUND Paediatric Solid Neoplasms (PSN are a global problem. There is significant variation of incidence of paediatric solid neoplasms in various regions of the world. Benign tumours are more common than cancer. In an effort to better understand the prevalence of paediatric solid tumours in our region, a retrospective review of the tumours diagnosed histopathologically was carried out. MATERIALS AND METHODS This is a retrospective study undertaken in a tertiary care hospital for a period of five years. All the benign and malignant paediatric solid tumours of children below 14 years from January 2012 to December 2016 were retrieved and analysed according to age, sex and histopathological diagnosis. Leukaemias were excluded from our study. All tumours were diagnosed on conventional haematoxylin and eosin-stained sections. RESULTS A total of 109 cases of solid paediatric tumours were received during this period. Of these, maximum of 30 tumours were of soft tissue tumours followed by Central Nervous System (CNS and bone tumours with 24 and 23 cases, respectively. 7 cases of blastomas were also observed. CONCLUSION This study showed benign and malignant tumours to be of near-equal prevalence. Soft tissue tumours were the most common. Ratio of benign tumours to malignant were almost equal below 4 years. Malignant tumours were higher in 5-9 years group.

  19. The Economics of Tourism in Jordan: A statistical Study during the Period 1990-2011

    Directory of Open Access Journals (Sweden)

    Fuad Kreishan, Dr.

    2014-06-01

    Full Text Available This study highlights the development in the Jordanian tourism sector, while pointing out the major changes in this sector and its impact on economic development during the period (1990-2011. The study revealed that the tourism market has become a vital and dynamic sector in Jordan and witnessed significant growth in both demand and supply sides. The study showed that the supply side response was compatible with the level of demand for tourism. Moreover, the study also concluded that the tourism industry makes a substantial contribution to the Jordanian economy. During the study period, it accounted for (11.2% of the GDP, employment in the tourism cluster, including indirect employment was estimated at around (10% of the work force. Finally, the contribution of the tourism sector alone in export earnings amounted to an average of (38% of the total exports.

  20. Depression in pregnancy and postpartum period.

    Science.gov (United States)

    Sood, Mamta; Sood, A K

    2003-01-01

    This prospective study was carried out in a service hospital, with the aim to study the prevalence and incidence of depression in pregnancy and postpartum period. Eighty Four consecutive patients attending the antenatal outpatient in the Obstetrics & Gynaecology department in their last trimester of pregnancy were recruited for the study. They were assessed on Beck Depression Inventory thrice viz. during third trimester of pregnancy, within 3 days of delivery (early postpartum period) & within 4-8 weeks of delivery (late postpartum period).The prevalence of depression was 8.3%, 20% and 12.8% respectively at three ratings. The incidence was 16% and 10% in the early & late postpartum period respectively. Further analysis revealed that depression in pregnancy correlated significantly with depression in early postpartum period, but not with late postpartum period. Depression in early postpartum period correlated with depression in late postpartum period.These findings have implications for early detection and care of women at risk for developing depression.

  1. PERIOD ESTIMATION FOR SPARSELY SAMPLED QUASI-PERIODIC LIGHT CURVES APPLIED TO MIRAS

    Energy Technology Data Exchange (ETDEWEB)

    He, Shiyuan; Huang, Jianhua Z.; Long, James [Department of Statistics, Texas A and M University, College Station, TX (United States); Yuan, Wenlong; Macri, Lucas M., E-mail: lmacri@tamu.edu [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX (United States)

    2016-12-01

    We develop a nonlinear semi-parametric Gaussian process model to estimate periods of Miras with sparsely sampled light curves. The model uses a sinusoidal basis for the periodic variation and a Gaussian process for the stochastic changes. We use maximum likelihood to estimate the period and the parameters of the Gaussian process, while integrating out the effects of other nuisance parameters in the model with respect to a suitable prior distribution obtained from earlier studies. Since the likelihood is highly multimodal for period, we implement a hybrid method that applies the quasi-Newton algorithm for Gaussian process parameters and search the period/frequency parameter space over a dense grid. A large-scale, high-fidelity simulation is conducted to mimic the sampling quality of Mira light curves obtained by the M33 Synoptic Stellar Survey. The simulated data set is publicly available and can serve as a testbed for future evaluation of different period estimation methods. The semi-parametric model outperforms an existing algorithm on this simulated test data set as measured by period recovery rate and quality of the resulting period–luminosity relations.

  2. Case study: Nutrition and training periodization in three elite marathon runners.

    Science.gov (United States)

    Stellingwerf, Trent

    2012-10-01

    Laboratory-based studies demonstrate that fueling (carbohydrate; CHO) and fluid strategies can enhance training adaptations and race-day performance in endurance athletes. Thus, the aim of this case study was to characterize several periodized training and nutrition approaches leading to individualized race-day fluid and fueling plans for 3 elite male marathoners. The athletes kept detailed training logs on training volume, pace, and subjective ratings of perceived exertion (RPE) for each training session over 16 wk before race day. Training impulse/load calculations (TRIMP; min × RPE = load [arbitrary units; AU]) and 2 central nutritional techniques were implemented: periodic low-CHO-availability training and individualized CHO- and fluid-intake assessments. Athletes averaged ~13 training sessions per week for a total average training volume of 182 km/wk and peak volume of 231 km/wk. Weekly TRIMP peaked at 4,437 AU (Wk 9), with a low of 1,887 AU (Wk 16) and an average of 3,082 ± 646 AU. Of the 606 total training sessions, ~74%, 11%, and 15% were completed at an intensity in Zone 1 (very easy to somewhat hard), Zone 2 (at lactate threshold) and Zone 3 (very hard to maximal), respectively. There were 2.5 ± 2.3 low-CHO-availability training bouts per week. On race day athletes consumed 61 ± 15 g CHO in 604 ± 156 ml/hr (10.1% ± 0.3% CHO solution) in the following format: ~15 g CHO in ~150 ml every ~15 min of racing. Their resultant marathon times were 2:11:23, 2:12:39 (both personal bests), and 2:16:17 (a marathon debut). Taken together, these periodized training and nutrition approaches were successfully applied to elite marathoners in training and competition.

  3. Surgery during holiday periods and prognosis in oesophageal cancer: a population-based nationwide Swedish cohort study.

    Science.gov (United States)

    Markar, Sheraz R; Wahlin, Karl; Mattsson, Fredrik; Lagergren, Pernilla; Lagergren, Jesper

    2016-09-06

    Previous studies indicate an increased short-term and long-term mortality from major cancer surgery performed towards the end of the working week or during the weekend. We hypothesised that the prognosis after major cancer surgery is also negatively influenced by surgery conducted during holiday periods. Population-based nationwide Swedish cohort study. Patients undergoing oesophagectomy for oesophageal cancer between 1987 and 2010. Among 1820 included patients, 206 (11.3%) and 373 (20.5%) patients were operated on during narrow and wide holiday periods, respectively. Narrow (7 weeks) and wide (14 weeks) Swedish holiday periods. 90-day all-cause, 5-year all-cause and 5-year disease-specific mortality. Narrow holiday period did not increase all-cause 90-day (HR=0.84, 95% CI 0.53 to 1.33), all-cause 5-year (HR=1.01, 95% CI 0.85 to 1.21) or disease-specific 5-year mortality (HR=1.04, 95% CI 0.87 to 1.26). Similarly, wide holiday period did not increase the risk of 90-day (HR=0.79, 95% CI 0.55 to 1.13), all-cause 5-year (HR=0.96, 95% CI 0.84 to 1.1) or disease-specific 5-year mortality (HR=1.03, 95% CI 0.89 to 1.19). No measurable effects of holiday periods on short-term or longer term mortality following surgery for oesophageal cancer were observed in this population-based study, indicating that an adequate surgical experience was maintained during holiday periods. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  4. Using social media as a strategy to address 'sophomore slump' in second year nursing students: A qualitative study.

    Science.gov (United States)

    Tower, Marion; Blacklock, Eddie; Watson, Bernadette; Heffernan, Catherine; Tronoff, Glenyss

    2015-11-01

    An important contributing factor to the shortfall in the nursing workforce is the high attrition rate of students from nursing programmes. Recently, researchers have begun to examine the 'sophomore slump' phenomenon, related to students' sense of low self-efficacy associated with learning in their second year of study, that may be related to attrition. Academic success is heavily influenced by self-efficacy, or a student's belief in their ability to be successful. Strategies that enhance self-efficacy include peer learning, which increases students' engagement and reinforces self-regulated learning. Social networking sites such as Facebook provide students the opportunity to take part in peer learning and may promote students' self-efficacy. The aim of the study was to develop a Facebook forum that utilised peer learning, to build self-efficacy related to learning, of students commencing into the second year of a three year nursing programme. Students commencing into year two of a Bachelor of Nursing programme were invited to join a Facebook forum to support their study. One hundred and ninety-eight students accepted the invitation. Data was collected over a twelve-week period. Text from the Facebook forum was downloaded and analysed thematically. Analysis suggests that Facebook forums may be a useful peer learning strategy to build students' self-efficacy related to study in the second year of nursing study. Students shared mastery experiences, provided modelling experiences, and used verbal persuasion to reframe problems which suggested that it helped build students' self-efficacy, and alleviated some of the physiological response associated with stress. The findings suggest that social media platforms are important tools by which students can engage in peer learning to build self-efficacy around their nursing studies. This may in part help address the 'sophomore slump' phenomenon, enhance students' learning experiences more widely, and impact on students

  5. On complex periodic motions and bifurcations in a periodically forced, damped, hardening Duffing oscillator

    International Nuclear Information System (INIS)

    Guo, Yu; Luo, Albert C.J.

    2015-01-01

    In this paper, analytically predicted are complex periodic motions in the periodically forced, damped, hardening Duffing oscillator through discrete implicit maps of the corresponding differential equations. Bifurcation trees of periodic motions to chaos in such a hardening Duffing oscillator are obtained. The stability and bifurcation analysis of periodic motion in the bifurcation trees is carried out by eigenvalue analysis. The solutions of all discrete nodes of periodic motions are computed by the mapping structures of discrete implicit mapping. The frequency-amplitude characteristics of periodic motions are computed that are based on the discrete Fourier series. Thus, the bifurcation trees of periodic motions are also presented through frequency-amplitude curves. Finally, based on the analytical predictions, the initial conditions of periodic motions are selected, and numerical simulations of periodic motions are carried out for comparison of numerical and analytical predictions. The harmonic amplitude spectrums are also given for the approximate analytical expressions of periodic motions, which can also be used for comparison with experimental measurement. This study will give a better understanding of complex periodic motions in the hardening Duffing oscillator.

  6. Comparative study of optical properties of the one-dimensional multilayer Period-Doubling and Thue-Morse quasi-periodic photonic crystals

    Directory of Open Access Journals (Sweden)

    Y. Bouazzi

    2012-10-01

    Full Text Available The last decades have witnessed the growing interest in the use of photonic crystal as a new material that can be used to control electromagnetic wave. Actually, not only the periodic structures but also the quasi-periodic systems have become significant structures of photonic crystals. This work deals with optical properties of dielectric Thue-Morse multilayer and Period-Doubling multilayer. We use the so-called Transfer Matrix Method (TMM to determine the transmission spectra of the structures. Based on the representation of the transmittance spectra in the visible range a comparative analysis depending on the iteration number, number of layers and incidence angle is presented.

  7. The identification and treatment of poor durability Karoo dolerite base course aggregate – evidence from case studies

    CSIR Research Space (South Africa)

    Leyland, RC

    2016-03-01

    Full Text Available that the poor performance of the case study materials was likely due to the poor durability of the materials, manifesting as a reduction in resistance to abrasion and attrition. The identification of the observed poor durability could not have been performed...

  8. Benefits of extensive recruitment effort persist during follow-ups and are consistent across age group and survey method. the TRAILS study

    NARCIS (Netherlands)

    E. Nederhof (Esther); F. Jörg (Frederike); D. Raven (Dennis); R. Veenstra (René); F.C. Verhulst (Frank); J. Ormel (Johan Hans); A.J. Oldehinkel (Albertine)

    2012-01-01

    textabstractBackground: Extensive recruitment effort at baseline increases representativeness of study populations by decreasing non-response and associated bias. First, it is not known to what extent increased attrition occurs during subsequent measurement waves among subjects who were

  9. Early Period of Modern Architecture in Turkey - A Case Study of Eskisehir

    Science.gov (United States)

    Karasozen, Rana

    2017-10-01

    modern buildings of Eskisehir as a medium-size city of Turkey will be examined in this study within the scope of the early modern architectural period of Turkey.

  10. The relation between prepregnancy sexuality and sexual function during pregnancy and the postpartum period: a prospective study.

    Science.gov (United States)

    Yıldız, Hatice

    2015-01-01

    This study examined the relation between sexual functions of women in prepregnancy (before conception) and during pregnancy and the postpartum period. This study was conducted on 59 healthy pregnant women. Participants were followed from the eighth week of gestation to 6 months after delivery. Sexual function during pregnancy and the postpartum period was shown to have a significant linear correlation with prepregnancy sexuality. There was no relation between pregnancy and postpartum sexuality. All of the participants who had prepregnancy sexual dysfunction continued to experience it during pregnancy, and the majority of them had a significant level of sexual dysfunction in the postpartum period. Our results showed that prepregnancy sexuality plays an important role in maintaining sexuality during pregnancy and the postpartum period.

  11. Study on wetting properties of periodical nanopatterns by a combinative technique of photolithography and laser interference lithography

    KAUST Repository

    Yang, Yung-Lang

    2010-03-01

    This study presents the wetting properties, including hydrophilicity, hydrophobicity and anisotropic behavior, of water droplets on the silicon wafer surface with periodical nanopatterns and hierarchical structures. This study fabricates one- and two-dimensional periodical nanopatterns using laser interference lithography (LIL). The fabrication of hierarchical structures was effectively achieved by combining photolithography and LIL techniques. Unlike conventional fabrication methods, the LIL technique is mainly used to control the large-area design of periodical nanopatterns in this study. The minimum feature size for each nanopattern is 100 nm. This study shows that the wetting behavior of one-dimensional, two-dimensional, and hierarchical patterns can be obtained, benefiting the development of surface engineering for microfluidic systems. © 2010 Elsevier B.V. All rights reserved.

  12. Study of 23 day periodicity of Blazar Mkn501 in 1997

    Science.gov (United States)

    Osone, S.

    2006-10-01

    We confirm a 23 day periodicity during a large flare in 1997 for X-ray data of X-ray satellite RXTE all sky monitor (ASM), 2 TeV gamma ray data from Utah Seven Telescope and HEGRA, with a Fourier analysis. We found the three results to be the same with a newly estimated error. We confirm the presence of a frequency dependent power (1/ f noise) in a frequency-power diagram. Further, we calculated a chance probability of the occurrence of the 23 day periodicity by considering the 1/ f noise and obtained a chance probability 4.88 × 10 -3 for the HEGRA data: this is more significant than the previous result by an order. We also obtained an indentical periodicity with another kind of timing analysis-epoch folding method for the ASM data and HEGRA data. We strongly suggest an existence of the periodicity. We divided the HEGRA data into two data sets, analyzed them with a Fourier method, and found an unstableness of the periodicity with a 3.4 sigma significance. We also analyzed an energy spectra of the X-ray data of a RXTE proportional counter array and we found that a combination of three physical parameters—a magnetic field, a Lorentz factor, and a beaming factor—is related to the periodicity.

  13. Should providers encourage realistic weight expectations and satisfaction with lost weight in commercial weight loss programs? a preliminary study.

    Science.gov (United States)

    Ames, Gretchen E; Thomas, Colleen S; Patel, Roshni H; McMullen, Jillian S; Lutes, Lesley D

    2014-01-01

    Attrition is a problem among patients who participate in commercial weight loss programs. One possible explanation is that if patients are unable to reach a weight that they expect to achieve, they may be more likely to drop out of treatment. This study investigated variables associated with attrition among 30 obese patients who completed a liquid meal replacement program (LMR) and enrolled in a 52-week Small Changes Maintenance intervention (SCM). Patients lost a median 18% of body weight during LMR and completed assessments about weight expectations and weight satisfaction pre- and post-SCM. Of the 30 patients who started SCM, 8 (27%) were lost to attrition. Odds of SCM attrition were higher in patients who lost ≤ 18.2% of pre-LMR weight (OR: 12.25, P = 0.035), had lower satisfaction (≤7) pre-SCM (OR: 10.11, P = 0.040), and who expected further weight loss of 9.1 kg or more pre-SCM (OR: 10.11, P = 0.040). SCM completers significantly increased weight loss expectations by a median of 2.3 kg from pre-SCM to post-SCM (WSR P = 0.049) that paralleled weight regained post-SCM (2.7 kg). After completion of a medically-supervised commercial weight loss program, patients with the greatest expectations for further weight loss and the lowest weight satisfaction were more likely to drop out of SCM. Failure to participate in maintenance treatment may lead to regain of greater than half of lost weight over the next year. Among SCM completers, lower expectations for further weight loss and greater weight satisfaction appeared to be associated with continued engagement in maintenance treatment.

  14. Refinement of the charcoal meal study by reduction of the fasting period.

    Science.gov (United States)

    Prior, Helen; Ewart, Lorna; Bright, Jonathan; Valentin, Jean-Pierre

    2012-05-01

    The aim of this investigation was to determine whether a shorter fasting period than the one historically employed for the charcoal meal test, could be used when measuring gastric emptying and intestinal transit within the same animal, and to ascertain whether the scientific outcome would be affected by this benefit to animal welfare. Rats and mice were fasted for 0, 3, 6 or 18 hours before the oral administration of vehicle or atropine. One hour later, the animals were orally administered a charcoal meal, then 20 minutes later, they were killed and the stomach and small intestine were removed. Intestinal transit time (the position of the charcoal front as a percentage of the total length of the small intestine) and relative gastric emptying (weight of stomach contents) were measured. Rats and mice fasted for six hours showed results for gastric emptying and intestinal transit which were similar to those obtained in animals fasted for 18 hours. Reducing the fasting period reduced the body weight loss in both species, and mice on shorter fasts could be group-housed, as hunger-induced fighting was lessened. Therefore, a fasting period of six hours was subsequently adopted for charcoal meal studies at our institution. 2011 FRAME.

  15. Special Features In Turbulent Mixing. Comparison between Periodic and Non Periodic Case

    Directory of Open Access Journals (Sweden)

    Mihai Costescu

    2006-12-01

    Full Text Available After hundreds of years of stability study, the problems of flow kinematics are far from complete solving. A modern theory appears in this field: the mixing theory. Its mathematical methods and techniques developed the significant relation between turbulence and chaos. The turbulence is an important feature of dynamic systems with few freedom degrees, the so-called far from equilibrium systems. These are widespread between the models of excitable media.Studying a mixing for a flow implies the analysis of successive stretching and folding phenomena for its particles, the influence of parameters and initial conditions. In the previous works, the study of the 3D non-periodic models exhibited a quite complicated behavior, involving some significant events - the so-called rare events. The variation of parameters had a great influence on the length and surface deformations. The 2D (periodic case is simpler, but significant events can also issue for irrational values of the length and surface versors, as was the situation in 3D case.The comparison between 2D and 3D case revealed interesting properties; therefore a modified 2D (periodic model is tested. The numerical simulations were realized in MapleVI, for searching special mathematical events. Continuing this work both from analytical and numeric standpoint would relieve useful properties for the turbulent mixing. A proximal target is to test some special functions for the periodic model, and to study the behavior of the structures realized by the model.

  16. Gender, gender roles and completion of nursing education: a longitudinal study.

    Science.gov (United States)

    McLaughlin, Katrina; Muldoon, Orla T; Moutray, Marianne

    2010-05-01

    The current worldwide nursing shortage and high attrition of nursing students remain a challenge for the nursing profession. The aim of this paper was to investigate how key psychological attributes and constructions differentiate between completers and non-completers of nursing education. A questionnaire including measures of gender role identity and perceived gender appropriateness of careers was administered to 384 students early in the first year of the course. At the end of the programme attrition rates were obtained. The findings indicate that males were more likely to leave the course than females. Furthermore, those who completed the course tended to view nursing as more appropriate for women, in contrast to the non-completers who had less gender typed views. The female-dominated nature of nursing, prevalent stereotypes and gender bias inherent in nursing education seem to make this an uncomfortable place for males and those with less gendered typed views. Whilst it is acknowledged that attrition is undoubtedly a complex issue with many contributing factors, the nursing profession need to take steps to address this bias to ensure their profession is open equally to both female and male recruits. Copyright 2009 Elsevier Ltd. All rights reserved.

  17. Using the factors that have a positive impact on the retention of low socioeconomic students to prepare accelerated enrolled nurses for the science units of a nursing degree. A Practice Report

    Directory of Open Access Journals (Sweden)

    Sheila Doggrell

    2015-03-01

    Full Text Available At a campus in a low socioeconomic (SES area, our University allows enrolled nurses entry into the second year of a Bachelor of Nursing, but attrition is high.  Using the factors, described by Yorke and Thomas (2003 to have a positive impact on the attrition of low SES students, we developed strategies to prepare the enrolled nurses for the pharmacology and bioscience units of a nursing degree with the aim of reducing their attrition.  As a strategy, the introduction of review lectures of anatomy, physiology and microbiology, was associated with significantly reduced attrition rates. The subsequent introduction of a formative website activity of some basic concepts in bioscience and pharmacology, and a workshop addressing study skills and online resources, were associated with a further reduction in attrition rates of enrolled nursing students in a Bachelor of Nursing

  18. Studying Short-Period Comets and Long-Period Comets Detected by WISE/NEOWISE

    Science.gov (United States)

    Kramer, Emily A.; Fernández, Yanga R.; Bauer, James M.; Stevenson, Rachel; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph; Walker, Russell G.; Lisse, Carey M.

    2014-11-01

    The Wide-field Infrared Survey Explorer (WISE) mission surveyed the sky in four infrared wavelength bands (3.4, 4.6, 12 and 22-micron) between January 2010 and February 2011 [1, 2]. During the mission, WISE serendipitously observed 160 comets, including 21 newly discovered objects. About 89 of the comets observed by WISE displayed a significant dust tail in the 12 and 22-micron (thermal emission) bands, showing a wide range of activity levels and dust morphology. Since the observed objects are a mix of both long-period comets (LPCs) and short-period comets (SPCs), differences in their activity can be used to better understand the thermal evolution that each of these populations has undergone. For the comets that displayed a significant dust tail, we have estimated the sizes and ages of the particles using dynamical models based on the Finson-Probstein method [3, 4]. For a selection of 40 comets, we have then compared these models to the data using a novel tail-fitting method that allows the best-fit model to be chosen analytically rather than subjectively. For comets that were observed multiple times by WISE, the dust tail particle properties were estimated separately, and then compared. We find that the dust tails of both LPCs and SPCs are primarily comprised of ~mm to cm sized particles, which were the result of emission that occurred several months to several years prior to the observations. The LPCs nearly all have strong dust emission close to the comet's perihelion distance, and the SPCs mostly have strong dust emission close to perihelion, but some have strong dust emission well before perihelion. Acknowledgments: This publication makes use of data products from (1) WISE, which is a joint project of UCLA and JPL/Caltech, funded by NASA; and (2) NEOWISE, which is a project of JPL/Caltech, funded by the Planetary Science Division of NASA. EK was supported by a NASA Earth and Space Sciences Fellowship. RS gratefully acknowledges support from the NASA

  19. The Effectiveness of Enhanced Cognitive Behavioural Therapy (CBT-E): A Naturalistic Study within an Out-Patient Eating Disorder Service.

    Science.gov (United States)

    Signorini, Rachel; Sheffield, Jeanie; Rhodes, Natalie; Fleming, Carmel; Ward, Warren

    2018-01-01

    The effectiveness of enhanced cognitive behavioural Therapy (CBT-E) for adults with a range of eating disorder presentations within routine clinical settings has been examined in only two known published studies, neither of which included a follow-up assessment period. The current study aimed to evaluate the effectiveness of CBT-E within an out-patient eating disorder service in Brisbane, Queensland, Australia, and incorporated a follow-up assessment period of approximately 20 weeks post-treatment. The study involved 114 adult females with a diagnosed eating disorder, who attended an average of 20-40 individual CBT-E sessions with a psychologist or a psychiatry registrar between 2009 and 2013. Of those who began treatment, 50% did not complete treatment, and the presence of psychosocial and environmental problems predicted drop-out. Amongst treatment completers, statistically and clinically significant improvements in eating disorder and general psychopathology were observed at post-treatment, which were generally maintained at the 20-week follow-up. Statistically significant improvements in eating disorder and general psychopathology were observed amongst the total sample. The findings, which were comparable to the previous Australian effectiveness study of CBT-E, indicate that CBT-E is an effective treatment for adults with all eating disorders within out-patient settings. Given the high attrition rate, however, minimizing drop-out appears to be an important consideration when implementing CBT-E within clinical settings.

  20. Soldier's Expectancies, Implications for Recruitment and Job Satisfaction

    National Research Council Canada - National Science Library

    Gelooven, Renier

    1999-01-01

    .... Also expectancies about a job influence attrition and job satisfaction. This paper uses results of several studies to describe the image of the soldiers job and its effects on recruitment, early attrition and job satisfaction.

  1. Application of Gamification in a College STEM Introductory Course: A Case Study

    Science.gov (United States)

    Machajewski, Szymon Tomasz

    2017-01-01

    Between 2000 and 2016, the STEM industry reportedly added jobs at the rate of 28% while all jobs were growing at only 6%. However, 48% of bachelor's degree students and 69% of associate's degree students in STEM majors left their program of study between 2003 and 2009. The high attrition rate is often attributed to low student engagement, boredom,…

  2. Efforts Aimed To Reduce Attrition in Antimalarial Drug Discovery: A Systematic Evaluation of the Current Antimalarial Targets Portfolio.

    Science.gov (United States)

    Chaparro, María Jesús; Calderón, Félix; Castañeda, Pablo; Fernández-Alvaro, Elena; Gabarró, Raquel; Gamo, Francisco Javier; Gómez-Lorenzo, María G; Martín, Julio; Fernández, Esther

    2018-04-13

    Malaria remains a major global health problem. In 2015 alone, more than 200 million cases of malaria were reported, and more than 400,000 deaths occurred. Since 2010, emerging resistance to current front-line ACTs (artemisinin combination therapies) has been detected in endemic countries. Therefore, there is an urgency for new therapies based on novel modes of action, able to relieve symptoms as fast as the artemisinins and/or block malaria transmission. During the past few years, the antimalarial community has focused their efforts on phenotypic screening as a pragmatic approach to identify new hits. Optimization efforts on several chemical series have been successful, and clinical candidates have been identified. In addition, recent advances in genetics and proteomics have led to the target deconvolution of phenotypic clinical candidates. New mechanisms of action will also be critical to overcome resistance and reduce attrition. Therefore, a complementary strategy focused on identifying well-validated targets to start hit identification programs is essential to reinforce the clinical pipeline. Leveraging published data, we have assessed the status quo of the current antimalarial target portfolio with a focus on the blood stage clinical disease. From an extensive list of reported Plasmodium targets, we have defined triage criteria. These criteria consider genetic, pharmacological, and chemical validation, as well as tractability/doability, and safety implications. These criteria have provided a quantitative score that has led us to prioritize those targets with the highest probability to deliver successful and differentiated new drugs.

  3. Periodic precursors of nonlinear dynamical transitions

    International Nuclear Information System (INIS)

    Jiang Yu; Dong Shihai; Lozada-Cassou, M.

    2004-01-01

    We study the resonant response of a nonlinear system to external periodic perturbations. We show by numerical simulation that the periodic resonance curve may anticipate the dynamical instability of the unperturbed nonlinear periodic system, at parameter values far away from the bifurcation points. In the presence of noise, the buried intrinsic periodic dynamics can be picked out by analyzing the system's response to periodic modulation of appropriate intensity

  4. Why students leave in the UK: an integrative review of the international research literature.

    Science.gov (United States)

    Cameron, Joan; Roxburgh, Michelle; Taylor, Julie; Lauder, William

    2011-04-01

    The purpose of this integrative review of the literature was to find and review international research studies that explored student attrition to determine what is known about the topic and to identify gaps in the research with a view to addressing the situation in the UK. Attrition from nursing programmes is a serious problem in the UK. It is recognised as a complex phenomenon, not attributable to a single cause. Regardless of actual attrition rates and trends, departments of nursing are challenged to perform in a business-like manner. Consequently, every student lost to a programme of study equates to a financial penalty for the department and to the future workforce and community.   Integrative review of the literature. Using electronic databases and specific search terms, 18 articles were identified and reviewed. Findings from the identified international research literature were analysed using qualitative content analysis. Four broad themes that accounted for factors of relevance to attrition were identified: Social, Prediction, Programme and Personal. Retention studies are fraught with methodological problems. These include incomplete or inaccurate data and low response rates. Attrition early in programmes may be attributed to a failure to understand the roles of nurses in contemporary societies. This has led to dissatisfaction with programmes and academic failure, as students may underestimate the intellectual demands of their programmes. Attrition later in the programme may be attributed to a combination of personal factors that culminate in a personal crisis. The research literature suggests that stereotyping of nurses is a major factor in attrition. Both professions need to find ways of communicating contemporary roles to wider society. © 2010 Blackwell Publishing Ltd.

  5. Holonomic systems for period mappings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jingyue, E-mail: jychen@brandeis.edu [Department of Mathematics, Brandeis University, Waltham, MA 02454 (United States); Huang, An, E-mail: anhuang@math.harvard.edu [Department of Mathematics, Harvard University, Cambridge, MA 02138 (United States); Lian, Bong H., E-mail: lian@brandeis.edu [Department of Mathematics, Brandeis University, Waltham, MA 02454 (United States)

    2015-09-15

    Period mappings were introduced in the sixties [4] to study variation of complex structures of families of algebraic varieties. The theory of tautological systems was introduced recently [7,8] to understand period integrals of algebraic manifolds. In this paper, we give an explicit construction of a tautological system for each component of a period mapping. We also show that the D-module associated with the tautological system gives rise to many interesting vanishing conditions for period integrals at certain special points of the parameter space.

  6. Study of Navy Enlisted Attrition: Race, Ethnicity, and Type of Occupation

    National Research Council Canada - National Science Library

    Carroll, James M

    2008-01-01

    .... The study uses a special database developed by the Defense Manpower Data Center in Monterey, CA, that contains the records of 186,938 male recruits who enlisted in the Navy during calendar years 1996 through 2000...

  7. Special Education Teacher Burnout: A Synthesis of Research from 1979 to 2013

    Science.gov (United States)

    Brunsting, Nelson C.; Sreckovic, Melissa A.; Lane, Kathleen Lynne

    2014-01-01

    Teacher burnout occurs when teachers undergoing stress for long periods of time experience emotional exhaustion, depersonalization, and lack of personal accomplishment (Maslach, 2003). Outcomes associated with burnout include teacher attrition, teacher health issues, and negative student outcomes. Special educators are at high risk for burnout as…

  8. [Study on dynamic accumulation of index components from Bupleurum chinense in various collecting periods].

    Science.gov (United States)

    Wang, Qi-shuai; Li, Xiao-kun; Yang, Yun; Xiao, Gong-sheng; Feng, Wei-sheng

    2010-08-01

    To study the dynamic change law of volatile oil, saikosaponin a, d and alcohol-extract from Bupleurum chinense at Songxian region in Henan province, and to explore the optimal harvest period of Bupleurum chinense. With the contents of saikosaponin a and d, absorbance of volatile oil and percentage of alcohol-extract as indexes, HPLC-ELSD and ultraviolet spectrophotometry were successively used to analyze them. There are obvious differences among the contents of volatile oil, saikosaponin a, d and alcohol-extract in various collecting periods sample, the absorption of volatile oil in distillation was the highest in October, the content of saikosaponin a was the highest in September, the saikosaponin d in December and the percentage of alcohol-extract in October. The optimal harvest period of Bupleurum chinense at Songxian region in Henan is identified, which can provide scientific basis for crude drug production and processing.

  9. Walking in Multiple Worlds: A Narrative Inquiry of William "Anutnurnerciraq" Beans, a Yup'ik Elder and Alaskan Educator

    Science.gov (United States)

    Syljuberget, Dan R.

    2010-01-01

    With the highest attrition rate of any minority group enrolled in higher education institutions, American Indian/Alaska Native students rightly garner considerable attention. Researchers and administrators study the factors for both attrition and persistence. Such scrutiny calls for studies of those individuals who successfully navigated the…

  10. The depression in women in pregnancy and postpartum period: A follow-up study.

    Science.gov (United States)

    Kirkan, Tulay Sati; Aydin, Nazan; Yazici, Esra; Aslan, Puren Akcali; Acemoglu, Hamit; Daloglu, Ali Gokhan

    2015-06-01

    This was a follow-up study to determine postpartum depression (PPD) and its causes in a population previously evaluated in the first trimester of pregnancy. The study sample consisted of pregnant women who were evaluated in the first trimester and 360 women who were re-evaluated in the postpartum period. Detailed sociodemographic data were obtained from the women, and depression was assessed with the Edinburgh Postpartum Depression scale (EPDS) and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM) Axis I Disorders (SCID-I). In this follow-up study, the prevalence of PPD was 35% (n = 126). A depressive disorder in the first trimester of pregnancy, previous mental disorder, somatic disorder, exposure to domestic violence during pregnancy, baby's staying in the incubator and not breastfeeding were predictors of PPD. Exposure to violence and a history of previous depression predicted depression both in pregnancy and in the postpartum period. Depression rates are high in Eastern Turkey. Exposure to violence during pregnancy and the existence of a previous mental disorder were risk factors for perinatal depression in this study. Performing screening tests can identify women at risk of pregnancy-related depression. Prevention programs should be established in areas where the prevalence of depression is high. © The Author(s) 2014.

  11. Periodic feedback stabilization for linear periodic evolution equations

    CERN Document Server

    Wang, Gengsheng

    2016-01-01

    This book introduces a number of recent advances regarding periodic feedback stabilization for linear and time periodic evolution equations. First, it presents selected connections between linear quadratic optimal control theory and feedback stabilization theory for linear periodic evolution equations. Secondly, it identifies several criteria for the periodic feedback stabilization from the perspective of geometry, algebra and analyses respectively. Next, it describes several ways to design periodic feedback laws. Lastly, the book introduces readers to key methods for designing the control machines. Given its coverage and scope, it offers a helpful guide for graduate students and researchers in the areas of control theory and applied mathematics.

  12. Key challenges of human resources for health in India

    Directory of Open Access Journals (Sweden)

    Priya Sinha

    2016-01-01

    Full Text Available Background and Objective Since independence the efforts have been to strengthen the health infrastructure, its accessibility and coverage. The human resources for health have been an important determinant for system but it has received significance recently. Even government expenditure on health has remained at not more than 1% of Gross Domestic Product which is very less as compared to world standard. Now the biggest challenge is the shortage of skilled human resource for health at all levels in the healthcare delivery system. The article aimed at understanding the current status of human resources for health and initiatives adopted to deal with existing shortage and to highlight factors leading to further shortage and to bring to notice the use of talent management strategy as a retention tool. Review Methodology The review used descriptive research design using secondary sources from journals-articles using key words. The study also used exclusion and inclusion criteria to select the articles. The study was done using extensive review of literature on health sector, health workforce, its availability and scarcity due to attrition/emigration in India. The critical review helped in setting objective for the study. Findings The review of articles provided insight into the current status of health workforce in India. The earlier studies emphasized that gap between demand and supply of human resource for health is mainly due to increasing population and burden of diseases. Studies have now identified other factors leading to further shortage as attrition/emigration of skilled health workforce. Most of the initiatives are mainly directed towards increasing supply of human resources for health to deal with the scarcity and less emphasis to control attrition. Few studies highlighted the use of talent management strategy to deal with the challenges of attrition and emigration that helps in retention and controlling further shortage. Recommendations

  13. Groundwater-quality data in 12 GAMA study units: Results from the 2006–10 initial sampling period and the 2008–13 trend sampling period, California GAMA Priority Basin Project

    Science.gov (United States)

    Mathany, Timothy M.

    2017-03-09

    The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey in cooperation with the California State Water Resources Control Board. From 2004 through 2012, the GAMA-PBP collected samples and assessed the quality of groundwater resources that supply public drinking water in 35 study units across the State. Selected sites in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. Twelve of the study units, initially sampled during 2006–11 (initial sampling period) and sampled a second time during 2008–13 (trend sampling period) to assess temporal trends, are the subject of this report.The initial sampling was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies in the 12 study units. In these study units, 550 sampling sites were selected by using a spatially distributed, randomized, grid-based method to provide spatially unbiased representation of the areas assessed (grid sites, also called “status sites”). After the initial sampling period, 76 of the previously sampled status sites (approximately 10 percent in each study unit) were randomly selected for trend sampling (“trend sites”). The 12 study units sampled both during the initial sampling and during the trend sampling period were distributed among 6 hydrogeologic provinces: Coastal (Northern and Southern), Transverse Ranges and Selected Peninsular Ranges, Klamath, Modoc Plateau and Cascades, and Sierra Nevada Hydrogeologic Provinces. For the purposes of this trend report, the six hydrogeologic provinces were grouped into two hydrogeologic regions based on location: Coastal and Mountain.The groundwater samples were analyzed for a number of synthetic organic

  14. Critical health infrastructure for refugee resettlement in rural Australia: case study of four rural towns.

    Science.gov (United States)

    Sypek, Scott; Clugston, Gregory; Phillips, Christine

    2008-12-01

    To explore the reported impact of regional resettlement of refugees on rural health services, and identify critical health infrastructure for refugee resettlement. Comparative case study, using interviews and situational analysis. Four rural communities in New South Wales, which had been the focus of regional resettlement of refugees since 1999. Refugees, general practitioners, practice managers and volunteer support workers in each town (n = 24). The capacity of health care workers to provide comprehensive care is threatened by low numbers of practitioners, and high levels of turnover of health care staff, which results in attrition of specialised knowledge among health care workers treating refugees. Critical health infrastructure includes general practices with interest and surge capacity, subsidised dental services, mental health support services; clinical support services for rural practitioners; care coordination in the early settlement period; and a supported volunteer network. The need for intensive medical support is greatest in the early resettlement period for 'catch-up' primary health care. The difficulties experienced by rural Australia in securing equitable access to health services are amplified for refugees. While there are economic arguments about resettlement of refugees in regional Australia, the fragility of health services in regional Australia should also be factored into considerations about which towns are best suited to regional resettlement.

  15. A study on the effect of exclusion period on the suicidal risk among the insured.

    Science.gov (United States)

    Yip, Paul S F; Chen, Feng

    2014-06-01

    An exclusion period (usually from 12 months to 2 years) is usually found in life insurance policies as a precautionary measure to prohibit people from insuring their lives with the intent to kill themselves shortly thereafter. Several studies have been conducted to investigate the effect of exclusion periods on the risk of suicide among the insured in the US and Australia. However, while Hong Kong has experienced an increase in the number of suicides among the insured, little is known about the dynamic between the exclusion period and suicide in Asia. Here we make use of death claims data from one of the major life insurance companies in Hong Kong to ascertain the impact of a 12-month exclusion period on suicide risk. We also use utility functions derived from economic theory to better understand individual choices regarding suicide among the insured. More specifically, we sought to determine whether there is a greater risk of suicide immediately following the 12-month exclusion period. We also examined whether the risk of suicide claims was higher than that of other non-suicidal claims. The study period for this investigation was from January 1, 1997 to December 31, 2011, during which time there were 1935 claims based on 1243 deaths. Of these, 197 were suicide-related claims for 106 suicide deaths. The mean number of life policies held by suicidal claimants and non-suicidal claimants was 1.6 and 1.4, respectively. The average/median size of the claims (total payment made on all policies held by the insured life) was HK$665,800/426,600 and HK$497,700/276,200 for suicidal and non-suicidal deaths, respectively. The policy lifetime of the claims, or the number of days from policy issuance to suicide occurrence, ranged from 38 to 7561 days, with a mean of 2209 days, a median of 1941 days, and a standard deviation of 1544 days. The peak density of suicide claims occurred on day 1039 of the policy. Our results revealed that suicide claims tend to occur earlier than other

  16. Women, Co-occurring Disorders, and Violence Study: evaluation design and study population.

    Science.gov (United States)

    McHugo, G J; Kammerer, N; Jackson, E W; Markoff, L S; Gatz, M; Larson, M J; Mazelis, R; Hennigan, K

    2005-03-01

    The Women, Co-occurring Disorders, and Violence Study (WCDVS) was a multi-site cooperative study to evaluate new service models for women with co-occurring mental health and substance use disorders and a history of physical and/or sexual abuse. Despite common features in the service interventions and evaluation procedures, diversity across the nine sites plus differences introduced by non-random assignment led to numerous methodological challenges. This article describes the design, measurement, and analysis decisions behind the WCDVS and lays the foundation for understanding participant-level outcomes and service costs. This article also describes the study population, as recruited and following attrition at the 6-month follow-up, in order to address the threat of selection bias to inferences drawn from this multi-site study.

  17. Supersymmetrically transformed periodic potentials

    OpenAIRE

    C, David J. Fernandez

    2003-01-01

    The higher order supersymmetric partners of a stationary periodic potential are studied. The transformation functions associated to the band edges do not change the spectral structure. However, when the transformation is implemented for factorization energies inside of the forbidden bands, the final potential will have again the initial band structure but it can have bound states encrusted into the gaps, giving place to localized periodicity defects.

  18. Study of electromagnetic wave scattering by periodic density irregularities in plasma

    International Nuclear Information System (INIS)

    Lyle, R.; Kuo, S.P.; Huang, J.

    1995-01-01

    A quasi-particle approach is used to formulate wave propagation and scattering in a periodically structured plasma. The theory is then applied to study the effect of bottomside sinusoidal (BSS) irregularities on the propagation of beacon satellites signals through the ionosphere. In this approach, the radio wave is treated as a distribution of quasi-particles described by a Wigner distribution function governed by a transport equation. The irregularities providing the collisional effect are modeled as a two dimensional density modulation on a uniform background plasma. The present work generalizes the previous work by including the spectral bandwidth (Δk/k) effect of the spatially periodic irregularities on the transionospheric signal propagation. The collision of quasi-particles with the irregularities modifies the quasi-particle distribution and give rise to the wave scattering phenomenon. The multiple scattering process is generally considered in this deterministic analysis of radio wave scattering off the ionospheric density irregularities. The analysis shows that this two dimensional density grating effectively modulates the intensity of the beacon satellite signals. This spatial modulation of the wave intensity is converted into time modulation due to the drift of the ionospheric irregularities, which then results in the scintillation of the beacon satellite signals

  19. Critical periods after stroke study: translating animal stroke recovery experiments into a clinical trial

    Science.gov (United States)

    Dromerick, Alexander W.; Edwardson, Matthew A.; Edwards, Dorothy F.; Giannetti, Margot L.; Barth, Jessica; Brady, Kathaleen P.; Chan, Evan; Tan, Ming T.; Tamboli, Irfan; Chia, Ruth; Orquiza, Michael; Padilla, Robert M.; Cheema, Amrita K.; Mapstone, Mark E.; Fiandaca, Massimo S.; Federoff, Howard J.; Newport, Elissa L.

    2015-01-01

    Introduction: Seven hundred ninety-five thousand Americans will have a stroke this year, and half will have a chronic hemiparesis. Substantial animal literature suggests that the mammalian brain has much potential to recover from acute injury using mechanisms of neuroplasticity, and that these mechanisms can be accessed using training paradigms and neurotransmitter manipulation. However, most of these findings have not been tested or confirmed in the rehabilitation setting, in large part because of the challenges in translating a conceptually straightforward laboratory experiment into a meaningful and rigorous clinical trial in humans. Through presentation of methods for a Phase II trial, we discuss these issues and describe our approach. Methods: In rodents there is compelling evidence for timing effects in rehabilitation; motor training delivered at certain times after stroke may be more effective than the same training delivered earlier or later, suggesting that there is a critical or sensitive period for strongest rehabilitation training effects. If analogous critical/sensitive periods can be identified after human stroke, then existing clinical resources can be better utilized to promote recovery. The Critical Periods after Stroke Study (CPASS) is a phase II randomized, controlled trial designed to explore whether such a sensitive period exists. We will randomize 64 persons to receive an additional 20 h of upper extremity therapy either immediately upon rehab admission, 2–3 months after stroke onset, 6 months after onset, or to an observation-only control group. The primary outcome measure will be the Action Research Arm Test (ARAT) at 1 year. Blood will be drawn at up to 3 time points for later biomarker studies. Conclusion: CPASS is an example of the translation of rodent motor recovery experiments into the clinical setting; data obtained from this single site randomized controlled trial will be used to finalize the design of a Phase III trial. PMID

  20. Critical Periods after Stroke Study: Translating animal stroke recovery experiments into a clinical trial

    Directory of Open Access Journals (Sweden)

    Alexander W Dromerick

    2015-04-01

    Full Text Available Introduction: 795,000 Americans will have a stroke this year, and half will have a chronic hemiparesis. Substantial animal literature suggests that the mammalian brain has much potential to recover from acute injury using mechanisms of neuroplasticity, and that these mechanisms can be accessed using training paradigms and neurotransmitter manipulation. However, most of these findings have not been tested or confirmed in the rehabilitation setting, in large part because of the challenges in translating a conceptually straightforward laboratory experiment into a meaningful and rigorous clinical trial in humans. Through presentation of methods for a Phase II trial, we discuss these issues and describe our approach. Methods: In rodents there is compelling evidence for timing effects in rehabilitation; motor training delivered at certain times after stroke may be more effective than the same training delivered earlier or later, suggesting that there is a critical or sensitive period for strongest rehabilitation training effects. If analogous critical/sensitive periods can be identified after human stroke, then existing clinical resources can be better utilized to promote recovery. The Critical Periods after Stroke Study (CPASS is a phase II randomized, controlled trial designed to explore whether such a sensitive period exists. We will randomize 64 persons to receive an additional 20 hours of upper extremity therapy either immediately upon rehab admission, 2-3 months after stroke onset, 6 months after onset, or to an observation-only control group. The primary outcome measure will be the Action Research Arm Test at one year. Blood will be drawn at up to 3 time points for later biomarker studies. Conclusion: CPASS is an example of the translation of rodent motor recovery experiments into the clinical setting; data obtained from this single site randomized controlled trial will be used to finalize the design of a Phase III trial.

  1. Quasi-periodic synchronisation of self-modulation oscillations in a ring chip laser by an external periodic signal

    International Nuclear Information System (INIS)

    Aulova, T V; Kravtsov, Nikolai V; Lariontsev, E G; Chekina, S N

    2011-01-01

    The synchronisation of periodic self-modulation oscillations in a ring Nd:YAG chip laser under an external periodic signal modulating the pump power has been experimentally investigated. A new quasi-periodic regime of synchronisation of self-modulation oscillations is found. The characteristic features of the behaviour of spectral and temporal structures of synchronised quasi-periodic oscillations with a change in the external signal frequency are studied. (control of laser radiation parameters)

  2. Preliminary dating study of clay tablet from Neo-Babylonian period

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rodrigo P. da, E-mail: rodrigo.silva@unasp.edu.br [Centro Universitario Adventista de Sao Paulo (UNASP), Sao Paulo, SP (Brazil); Tudela, Diego R.G.; Hazenfratz, Roberto; Munita, Casimiro S., E-mail: camunita@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Tatumi, Sonia H.; Yee, Marcio; Mittani, Juan C. R., E-mail: sonia.tatumi@gmail.com [Universidade Federal de Sao Paulo (UNIFESP), Santos, SP (Brazil)

    2013-07-01

    This work focuses on the archaeometric study of three clay tablet fragments named BAB{sub 1}, BAB{sub 2} and BAB{sub 3}. One of them, BAB{sub 1}, probably was manufactured in the Middle East during the Neo-Babylonian period, and contains inscriptions in cuneiform characters. The other two samples BAB{sub 2} and BAB{sub 3} also contain cuneiform characters, but in incomplete sentences. Typological studies in agreement with historical records suggest that the artifacts were manufactured in the 6{sup th} century B.C. during the dynasty of Nebuchadnezzar, Great King of Babylon. The age was determined by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The annual dose rate for both TL and OSL dating was calculated with uranium, thorium and potassium concentrations determined by instrumental neutron activation analysis (INAA). Additional studies were performed using electron paramagnetic resonance (EPR) to determine the firing temperature, in order to verify if different firing temperatures were associated to different ages. Finally, X-ray diffraction analysis (XRD) was applied to the fragments to verify potential mineralogical differences, indicating different technological choices in the ceramic manufacture (like the choice of clay pastes and firing temperature). (author)

  3. Preliminary dating study of clay tablet from Neo-Babylonian period

    International Nuclear Information System (INIS)

    Silva, Rodrigo P. da; Tudela, Diego R.G.; Hazenfratz, Roberto; Munita, Casimiro S.; Tatumi, Sonia H.; Yee, Marcio; Mittani, Juan C. R.

    2013-01-01

    This work focuses on the archaeometric study of three clay tablet fragments named BAB 1 , BAB 2 and BAB 3 . One of them, BAB 1 , probably was manufactured in the Middle East during the Neo-Babylonian period, and contains inscriptions in cuneiform characters. The other two samples BAB 2 and BAB 3 also contain cuneiform characters, but in incomplete sentences. Typological studies in agreement with historical records suggest that the artifacts were manufactured in the 6 th century B.C. during the dynasty of Nebuchadnezzar, Great King of Babylon. The age was determined by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The annual dose rate for both TL and OSL dating was calculated with uranium, thorium and potassium concentrations determined by instrumental neutron activation analysis (INAA). Additional studies were performed using electron paramagnetic resonance (EPR) to determine the firing temperature, in order to verify if different firing temperatures were associated to different ages. Finally, X-ray diffraction analysis (XRD) was applied to the fragments to verify potential mineralogical differences, indicating different technological choices in the ceramic manufacture (like the choice of clay pastes and firing temperature). (author)

  4. Studies on aerosol properties during ICARB–2006 campaign period ...

    Indian Academy of Sciences (India)

    Synchronous measurements of Aerosol Optical Depth (AOD), Black Carbon (BC) aerosol mass concentration and aerosol particle size distribution were carried out during the campaign period at tropical urban regions of Hyderabad, India. Daily satellite datasets of DMSP-OLS were processed for night-time forest fires over ...

  5. Chaos to periodicity and periodicity to chaos by periodic perturbations in the Belousov-Zhabotinsky reaction

    International Nuclear Information System (INIS)

    Li Qianshu; Zhu Rui

    2004-01-01

    A three-variable model of the Belousov-Zhabotinsky reaction system subject to external sinusoidal perturbations is investigated by means of frequency spectrum analysis. In the period-1 window of the model, the transitions from periodicity to chaos are observed; in the chaotic window, the transitions from chaos to periodicity are found. The former might be understood by the circle map of two coupled oscillators, and the latter is partly explained by the resonance between the main frequency of the chaos and the frequency of the external periodic perturbations

  6. Predictors of breast feeding self-efficacy in the immediate postpartum period: A cross-sectional study.

    Science.gov (United States)

    Yang, Xiao; Gao, Ling-Ling; Ip, Wan-Yim; Sally Chan, Wai Chi

    2016-10-01

    to examine breast feeding self-efficacy and identify its predictors among mainland Chinese mothers in the early postpartum period. a cross-sectional descriptive questionnaire survey was conducted in a regional teaching hospital with childbirth rate over 3000 per year at Guangzhou, China from April 1 to July 14, 2014. a total of 571 Chinese mothers who were within 72-96hours post partum were recruited consecutively to the study. data were collected by the Chinese version of the Breastfeeding Self-efficacy Scale-Short Form (BSES-SF), the Network Support for Breastfeeding Scale (NSBS) and a socio-demographic data sheet. a total of 640 eligible women was approached and 571 mothers completed the study with the response rate of 89%. Mothers reported moderate level of breast feeding self-efficacy in the immediate postpartum period. The best-fit regression analysis revealed six variables that explained 43.9% of the variance in breast feeding self-efficacy in the immediate postpartum period. They were intention of breast feeding, support from husband, support from nurses/midwives, attending antenatal breast feeding classes, time from childbirth to initiate breast feeding and previous breast feeding experience. this study found six predictors of breast feeding self-efficacy in the immediate postpartum period. In order to increase maternal breast feeding self-efficacy level, a more women-centred approach is recommended. Mothers and fathers should be facilitated to attend antenatal classes on breast feeding. New mother' husband could be encouraged in supporting breast feeding. Nurses and midwives could encourage new mothers to initiate breast feeding as soon as possible. Further work to promote early mother-infant contact post birth, such as via skin to skin contact should also be facilitated where possible. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Contribution of Socioeconomic Status at 3 Life-Course Periods to Late-Life Memory Function and Decline: Early and Late Predictors of Dementia Risk.

    Science.gov (United States)

    Marden, Jessica R; Tchetgen Tchetgen, Eric J; Kawachi, Ichiro; Glymour, M Maria

    2017-10-01

    Both early life and adult socioeconomic status (SES) predict late-life level of memory; however, evidence is mixed on the relationship between SES and rate of memory decline. Further, the relative importance of different life-course periods for rate of late-life memory decline has not been evaluated. We examined associations between life-course SES and late-life memory function and decline. Health and Retirement Study participants (n = 10,781) were interviewed biennially from 1998-2012 (United States). SES measurements for childhood (composite score including parents' educational attainment), early adulthood (high-school or college completion), and older adulthood (income, mean age 66 years) were all dichotomized. Word-list memory was modeled via inverse-probability weighted longitudinal models accounting for differential attrition, survival, and time-varying confounding, with nonrespondents retained via proxy assessments. Compared to low SES at all 3 points (referent), stable, high SES predicted the best memory function and slowest decline. High-school completion had the largest estimated effect on memory (β = 0.19; 95% confidence interval: 0.15, 0.22), but high late-life income had the largest estimated benefit for slowing declines (for 10-year memory change, β = 0.35; 95% confidence interval: 0.24, 0.46). Both early and late-life interventions are potentially relevant for reducing dementia risk by improving memory function or slowing decline. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Period04 FCAPT uvby Photometric Studies of Eight Magnetic CP Stars

    Science.gov (United States)

    Adelman, Saul J.; Dukes, Robert J.

    2014-06-01

    We present Four College Automated Photometric Telescope (FCAPT) differential Stromgren uvby photometry of 8 magnetic CP (mCP) stars: HD 5797 (V551 Cas), HD 26792 (DH Cam), HD 27309 (56 Tau, V724 Tau), HD 49713 (V740 Mon), HD 74521 (49 Cnc, BI Cnc), HD 120198 (84 UMa, CR UMa), HD 171263 (QU Ser), and HD 215441 (GL Lac, Babcock's star). Our data sets are larger than those of most mCP stars in the literature. These are the first FCAPT observations of HD 5797, HD 26792, HD 49713, and HD 171263. Those for the remaining four stars substantially extend published FCAPT data. The FCAPT observed some stars for a longer time range and with greater accuracy than other optical region automated photometric telescopes.Our goals were to determine very accurate periods, the u, v, b, and y amplitudes, and if there were any long period periods. In addition we wanted to compare our results with those of magnetic field measurements to help interpret the light curves.We used the Period04 computer program to analyze the light curves. This program provides errors for the derived quantities as it fits the light curve. Our derived periods of 68.046 +/- 0.008 days for HD 5797, 3.80205 +/- 0.00006 days for HD 26792, 1.56889 +/- 0.000002 days for HD 27309, 2.13536 +/- 0.00002 days for HD 49713, 7.0505 +/- 0.0001 days for HD 74521, 1.38577 +/- 0.000004 days for HD 120198, 3.9974 +/- 0.0001days for HD 171263, and 9.487792 +/- 0.00005 days for HD 215441 are refinements of the best determinations in the literature.

  9. Comparative study of representations of professional autonomy produced by first and last-period undergraduate nursing students

    Directory of Open Access Journals (Sweden)

    Érick Igor dos Santos

    2017-09-01

    Full Text Available ABSTRACT Objective: to compare the social representations of professional nurse autonomy produced by first and last-period undergraduate nursing students. Method: qualitative, descriptive and exploratory study, based on the structural approach of social representations, the Central Core Theory, carried out with 171 students from three federal public universities, using the free association technique on the object “professional nurse autonomy”. The data were submitted to EVOC 2005 software and to similarity analysis. Results: care was the central core of the representational structure identified among the students of the first period. Among last-period students, knowledge stood out as a core element. The term responsibility was identified as common to both central cores. Conclusion: regarding professional autonomy, the results point to an overlapping process of the reified and consensual universes during the undergraduate course. However, responsibility, inherent in the profession, remains cross-sectional. For the first period students, autonomy is resignified in a practical and attitudinal way, whereas for the last period students, the knowledge acquired stimulates them to assign meaning to professional autonomy with a cognitive and attitudinal representation. The data can support the use of innovative teaching practices in nursing undergraduate courses.

  10. Numerical study of two disks settling in an Oldroyd-B fluid: From periodic interaction to chaining

    Science.gov (United States)

    Pan, Tsorng-Whay; Glowinski, Roland

    2017-12-01

    In this article, we present a numerical study of the dynamics of two disks sedimenting in a narrow vertical channel filled with an Oldroyd-B fluid. Two kinds of particle dynamics are observed: (i) a periodic interaction between the two disks, and (ii) the formation of a two-disk chain. For the periodic interaction of the two disks, two different motions are observed: (a) the two disks stay far apart and interact periodically, and (b) the two disks interact closely and then far apart in a periodic way, like the drafting, kissing, and tumbling of two disks sedimenting in a Newtonian fluid, due to a weak elastic force. Concerning the formation of a two-disk chain occurring at higher values of the elasticity number, either a tilted chain or a vertical chain is observed. Our simulations show that, as expected, the values of the elasticity and Mach numbers are the determining factors concerning the particle chain formation and its orientation.

  11. Iraqi architecture in mogul period

    Directory of Open Access Journals (Sweden)

    Hasan Shatha

    2018-01-01

    Full Text Available Iraqi architecture have many periods passed through it until now, each on from these periods have it is architectural style, also through time these styles interacted among us, to creating kind of space forming, space relationships, and architectural elements (detailed treatments, the research problem being from the multi interacted architectural styles causing some of confused of general characteristic to every style, that we could distinguish by it. Research tries to study architecture style through Mogul Conquest to Baghdad. Aim of research follow main characteristic for this architectural style in the Mogul periods on the level of form, elements, and treatments. Research depending on descriptive and analytical all buildings belong to this period, so from analyzing there style by, general form for building, architectural elements, and it architectural treatment, therefore; repeating this procedures to every building we get some similarities, from these similarities we can making conclusion about pure characteristic of the style of these period. Other side, we also discover some Dissimilar in the building periods, these will lead research to make what interacting among styles in this period, after all that we can drew clearly main characteristic of Architectural Style for Mogul Conquest in Baghdad

  12. Accommodating adolescent sleep-wake patterns: the effects of shifting the timing of sleep on training effectiveness.

    Science.gov (United States)

    Miller, Nita Lewis; Tvaryanas, Anthony P; Shattuck, Lawrence G

    2012-08-01

    This study evaluated the effect of accommodating adolescent sleep-wake patterns by altering the timing of the major sleep period of US Army recruits. The quasi-experimental study compared recruits assigned to one of two training companies: one with a customary sleep regimen (20:30 to 04:30) while the other employed a phase-delayed sleep regimen (23:00 to 07:00), the latter aligning better with biologically driven sleep-wake patterns of adolescents. The study was conducted during Basic Combat Training (BCT) at Fort Leonard Wood, Missouri. TRAINEES: The study included 392 trainees: 209 received the intervention, while 183 composed the Comparison group. Demographic and psychophysiological measures were collected on all trainees. Weekly assessments of subjective fatigue and mood, periodic physical fitness, marksmanship scores, and attrition rates from BCT were studied. Actigraphy was collected on approximately 24% of trainees. Based on actigraphy, trainees on the phase-delayed sleep schedule obtained 31 m more sleep/night than trainees on the customary sleep schedule. The Intervention group reported less total mood disturbance relative to baseline. Improvements in marksmanship correlated positively with average nightly sleep during the preceding week when basic marksmanship skills were taught. No differences were seen in physical fitness or attrition rates. In contrast to the Intervention group, the Comparison group was 2.3 times more likely to experience occupationally significant fatigue and 5.5 times more likely to report poor sleep quality. Accommodating adolescent sleep patterns significantly improves mental health and performance in the training environment.

  13. mPeriod2 Brdm1 and other single Period mutant mice have normal food anticipatory activity.

    Science.gov (United States)

    Pendergast, Julie S; Wendroth, Robert H; Stenner, Rio C; Keil, Charles D; Yamazaki, Shin

    2017-11-14

    Animals anticipate the timing of food availability via the food-entrainable oscillator (FEO). The anatomical location and timekeeping mechanism of the FEO are unknown. Several studies showed the circadian gene, Period 2, is critical for FEO timekeeping. However, other studies concluded that canonical circadian genes are not essential for FEO timekeeping. In this study, we re-examined the effects of the Per2 Brdm1 mutation on food entrainment using methods that have revealed robust food anticipatory activity in other mutant lines. We examined food anticipatory activity, which is the output of the FEO, in single Period mutant mice. Single Per1, Per2, and Per3 mutant mice had robust food anticipatory activity during restricted feeding. In addition, we found that two different lines of Per2 mutant mice (ldc and Brdm1) anticipated restricted food availability. To determine if FEO timekeeping persisted in the absence of the food cue, we assessed activity during fasting. Food anticipatory (wheel-running) activity in all Period mutant mice was also robust during food deprivation. Together, our studies demonstrate that the Period genes are not necessary for the expression of food anticipatory activity.

  14. "The Accommodation I Make Is Turning a Blind Eye": Faculty Support for Student Mothers in Higher Education

    Science.gov (United States)

    Dickson, Martina; Tennant, Lilly

    2018-01-01

    The levels of support which faculty provide to students have been linked to a number of positive effects on students such as lower rates of attrition, greater satisfaction with college life, enhanced self-concept, improved academic performance and more likelihood of remaining enrolled in college through stressful life periods. There are surely…

  15. External foam and the post-mortem period in freshwater drowning; results from a retrospective study in Amsterdam, the Netherlands.

    Science.gov (United States)

    Reijnen, G; Buster, M C; Vos, P J E; Reijnders, U J L

    2017-11-01

    Determining the time of death of bodies recovered from water can be difficult. A feature of drowning is the presence of external foam. This study describes the presence of external foam in relation to the post-mortem period. The study utilizes a database of death reports dated between January 2011 and July 2016. For bodies recovered from fresh water, the presence or absence of external foam was noted. In this study, 112 death reports are included. Of these reports, 18 mentioned external foam, which account for 16.1% of the entire study population. In the population with a post-mortem period of less than 24 h, external foam was detected in 27.7% of cases. All 18 incidents with external foam had an estimated post-mortem period of less than 24 h. In our study, external foam was only present in freshwater drowning cases with a post-mortem period of less than 24 h. Based on this finding, the presence of external foam may be useful as an additional indicator when estimating the time of death in freshwater drowning. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  16. Study on temperature sensitivity of topological insulators based on long-period fiber grating

    Science.gov (United States)

    Luo, Jianhua; Zhao, Chenghai; Li, Jianbo; He, Mengdong

    2017-06-01

    Based on a long-period fiber grating, we conducted experimental research on the temperature sensitivity of topological insulators. The long-period fiber grating and topological insulators solution were encapsulated in a capillary tube using UV glue, and the temperature response was measured. Within a range of 35 to 75 centigrade, one resonance dip of a long-period fiber grating exhibits a redshift of 1.536 nm. The temperature sensitivity is about 7.7 times of an ordinary long-period fiber grating's sensitivity (0.005 nm/°C). A numerical simulation is also performed on the basis of the experiments.

  17. Online Periodic Table: A Cautionary Note

    Science.gov (United States)

    Izci, Kemal; Barrow, Lloyd H.; Thornhill, Erica

    2013-01-01

    The purpose of this study was (a) to evaluate ten online periodic table sources for their accuracy and (b) to compare the types of information and links provided to users. Limited studies have been reported on online periodic table (Diener and Moore 2011; Slocum and Moore in "J Chem Educ" 86(10):1167, 2009). Chemistry students'…

  18. Physical explanation of the periodic table.

    Science.gov (United States)

    Ostrovsky, V N

    2003-05-01

    The Periodic Table of the elements, the most important generalization in chemistry, is often considered as a representative special case in the study of the relation between chemistry and physics. Its quantum interpretation was initiated, but not completed, by Niels Bohr. In this paper, post-Bohr conceptual developments are discussed from historical and epistemological points of view. The difference between high-precision numerical calculations for individual atoms and the theory of the periodic system as a whole is emphasized. Periodic laws met in Nature are not restricted to the chemical Periodic Table. A comparative study of these laws makes it possible to single out essential features that define the particular pattern of periodicity. It is shown that the periodic system of neutral ground state atoms now has a firm nonempirical quantum-theoretical basis. Alternative approaches, based on group theory and other mathematical schemes, are briefly discussed. It is argued that, while quantum theory is capable of fully accurate calculations for relatively simple atoms or molecular objects, the complexity of polyatomic molecules and chemical reactions guarantees the flourishing of chemistry as a separate scientific discipline.

  19. Searching for Satisfaction: Black Female Teachers' Workplace Climate and Job Satisfaction

    Science.gov (United States)

    Farinde-Wu, Abiola; Fitchett, Paul G.

    2018-01-01

    Job satisfaction may decrease teacher attrition. Furthermore, job satisfaction correlates with teacher retention, which may influence school building climate and student achievement. Potentially affecting students' progress and seeking to reduce attrition rates among Black teachers, this quantitative study uses data from the 2007-2008 Schools and…

  20. Study on wetting properties of periodical nanopatterns by a combinative technique of photolithography and laser interference lithography

    KAUST Repository

    Yang, Yung-Lang; Hsu, Chin-Chi; Chang, Tien-Li; Kuo, Long-Sheng; Chen, Ping-Hei

    2010-01-01

    This study presents the wetting properties, including hydrophilicity, hydrophobicity and anisotropic behavior, of water droplets on the silicon wafer surface with periodical nanopatterns and hierarchical structures. This study fabricates one

  1. Impact of Psychosocial Risk on Outcomes among Families Seeking Treatment for Obesity.

    Science.gov (United States)

    Phan, Thao-Ly T; Chen, Fang Fang; Pinto, Alison Taggi; Cox, Courtney; Robbins, Jennifer; Kazak, Anne E

    2018-04-02

    To test the hypothesis that children with elevated psychosocial risk would have increased attrition and worse weight outcomes in weight management treatment. This was a prospective cohort study of 100 new patients, aged 4-12 years, in a weight management clinic. Parents completed the Psychosocial Assessment Tool. Logistic regression analyses were conducted to calculate the odds of attrition from the clinic and a nonmeaningful change in body mass index (BMI) z-score (ie, psychosocial risk category, adjusting for child demographics and baseline weight category. The majority of patients were male (59%), black (36%) or white (43%), and had severe obesity (55%), and 59% of families were categorized as having moderate or high psychosocial risk. Over the 6-month period, 53% of families were lost to follow-up, and 67% did not have a clinically meaningful decrease in BMI z-score. Compared with children of families with low psychosocial risk, children of families with moderate or high psychosocial risk were 3.1 times (95% CI, 1.3-7.2 times) more likely to be lost to follow-up and 2.9 times (95% CI, 1.1-7.9 times) more likely to have a non-clinically meaningful change in BMI z-score. Children presenting with increased psychosocial risk have higher attrition and poorer weight outcomes, supporting the need for psychosocial screening as a standard component of pediatric weight management treatment. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Long-term dietary intervention trials: critical issues and challenges

    Directory of Open Access Journals (Sweden)

    Crichton Georgina E

    2012-07-01

    Full Text Available Abstract Background There are many challenges involved in running randomised controlled dietary intervention trials that investigate health outcomes. The aim of this paper was to evaluate the recruitment process, retention of participants and challenges faced in our dairy intervention trial, and to provide strategies to combat the difficulties of running long-term dietary intervention trials. Methods A 12-month, randomised, two-way crossover study was conducted in overweight adults with habitually low dairy food consumption to assess the effects of a high dairy intake (4 servings of reduced-fat dairy per day compared with a low dairy intake (1 serving of reduced-fat dairy per day on measures of cardiometabolic and cognitive health. On completion of the high dairy intake phase, each participant was interviewed about their experience in the trial and responses were used to evaluate the key issues for study participants. Results Although the recruitment target was achieved, high rates of attrition (49.3% and difficulties maintaining participant compliance (reported by 37.8% of participants were major threats to the viability of the study. Factors that contributed to the high attrition included inability to comply with the dietary requirements of the study protocol (27.0%, health problems or medication changes (24.3% and time commitment (10.8%. Conclusion Attrition and adherence to study requirements present challenges to trials requiring longer-term dietary change. Including a run-in period to further assess the motivation, commitment and availability of participants, maintaining regular contact with participants during control phases, minimising time commitment, providing flexibility with dietary requirements, facilitating positive experiences, and stringent monitoring of diet are some key recommendations for future dietary intervention trials. Trial registration Australia and New Zealand Clinical Trials Registry (ACTRN 12608000538347

  3. Study of poly hydrocarbons compounds (PAH) in air particulates and their variations in several periods of the year in Damascus city

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Al-Kharfan, K.; Mahzia, Y.; Ibrahim, S.

    2012-01-01

    A study of poly aromatic hydrocarbons (PAH) associated with suspended particulate and their variations in several periods of the year in several sites locations in Damascus City during the period of 2008-2009 was carried out. The studied sites were Zablatani (Ahdaasharea), Mohafaza square, Roken Eddin (Shamdine square) and Mezh (near AlAkram mosque), in addition to Soja as a reference site. The average concentrations of PAH associated with total particulates ranged between 0.97-70.11 ng/m3, which are higher than the average concentrations in the reference site (0.0013-0.75 ng/m3). Also, results have showed that the concentrations were maximal in the dry period comparing with the wet period, while they increased in the day period by 42% in comparison with the night period and decreased in the holidays, which indicates the impact of the traffic. In addition, the highest concentrations were recorded in Zablatani location in all study stages. On the other hand, the results of distribution study of the PAHs according to particle size showed that 81.65-93.51% of the total concentration of these compounds were associated with respiratory particulates (PM10). (author)

  4. Fusion reactor technology studies. Final report for period August 1, 1972 - October 31, 1978

    International Nuclear Information System (INIS)

    Kulcinski, G.L.; Maynard, C.W.

    1984-04-01

    Major accomplishments for the period August 1, 1972 - October 31, 1978 include the publishing of four comprehensive fusion reactor conceptual design studies; experimental studies in the areas of radiation damage, plasma-wall interactions, superconducting magnets and 14-MeV neutron cross sections; development of the concepts of carbon curtains and ISSEC's for use in fusion reactors; development of a neutron and gamma heating computer code, a radioactivity and afterheat computer code and a neutral transport computer code; and studies in the areas of RF heating for tokamaks and resource assessment for fusion reactors

  5. Existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems with several deviating arguments.

    Science.gov (United States)

    Fan, M; Wang, K; Jiang, D

    1999-08-01

    In this paper, we study the existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems. By using the method of coincidence degree and Lyapunov functional, a set of easily verifiable sufficient conditions are derived for the existence of at least one strictly positive (componentwise) periodic solution of periodic n-species Lotka-Volterra competition systems with several deviating arguments and the existence of a unique globally asymptotically stable periodic solution with strictly positive components of periodic n-species Lotka-Volterra competition system with several delays. Some new results are obtained. As an application, we also examine some special cases of the system we considered, which have been studied extensively in the literature. Some known results are improved and generalized.

  6. Workloads in Australian emergency departments a descriptive study.

    Science.gov (United States)

    Lyneham, Joy; Cloughessy, Liz; Martin, Valmai

    2008-07-01

    This study aimed to identify the current workload of clinical nurses, managers and educators in Australian Emergency Departments according to the classification of the department Additionally the relationship of experienced to inexperienced clinical staff was examined. A descriptive research method utilising a survey distributed to 394 Australian Emergency departments with a 21% response rate. Nursing workloads were calculated and a ratio of nurse to patient was established. The ratios included nurse to patient, management and educators to clinical staff. Additionally the percentage of junior to senior clinical staff was also calculated. Across all categories of emergency departments the mean nurse:patient ratios were 1:15 (am shift), 1:7 (pm shift) and 1:4 (night shift). During this period an average of 17.1% of attendances were admitted to hospital. There were 27 staff members for each manager and 23.3 clinical staff for each educator. The percentage of junior staff rostered ranged from 10% to 38%. Emergency nurses cannot work under such pressure as it may compromise the care given to patients and consequently have a negative effect on the nurse personally. However, emergency nurses are dynamically adjusting to the workload. Such conditions as described in this study could give rise to burnout and attrition of experienced emergency nurses as they cannot resolve the conflict between workload and providing quality nursing care.

  7. The impact of staff-poaching among radio stations in the Kumasi ...

    African Journals Online (AJOL)

    ... and lack of proper contract leads to staff-poaching. The study therefore recommends that there should be proper contract and good relationship between employers and employees which will help manage the high attrition rate in the radio stations. Key words: Staff-poaching, Attrition, Non-compete clause (CNC), predatory ...

  8. Shock dynamics in layered periodic media

    KAUST Repository

    Ketcheson, David I.; Leveque, Randall J.

    2012-01-01

    of shock waves in a one-dimensional periodic layered medium by a computational study of time-reversibility and entropy evolution. We find that periodic layered media tend to inhibit shock formation. For small initial conditions and large impedance variation

  9. Three dimensional periodic foundations for base seismic isolation

    International Nuclear Information System (INIS)

    Yan, Y; Mo, Y L; Cheng, Z; Shi, Z; Menq, F; Tang, Y

    2015-01-01

    Based on the concept of phononic crystals, periodic foundations made of periodic materials are investigated in this paper. The periodic foundations can provide low frequency band gaps, which cover the main frequency ranges of seismic waves. Therefore, the periodic foundations are able to protect the upper structures during earthquake events. In this paper, the basic theory of three dimensional periodic foundations is studied and the finite element method was used to conduct the sensitivity study. A simplified three-dimensional periodic foundation with a superstructure was tested in the field and the feasibility of three dimensional periodic foundations was proved. The test results showed that the response of the upper structure with the three dimensional periodic foundation was reduced under excitation waves with the main frequency falling in the attenuation zones. The finite element analysis results are consistent with the experimental data, indicating that three dimensional periodic foundations are a feasible way of reducing seismic vibrations. (paper)

  10. A Study of Stochastic Resonance in the Periodically Forced Rikitake Dynamo

    Directory of Open Access Journals (Sweden)

    Chien-Chih Chen Chih-Yuan Tseng

    2007-01-01

    Full Text Available The geodynamo has widely been thought to be an intuitive and selfsustained model of the Earth¡¦s magnetic field. In this paper, we elucidate how a periodic signal could be embedded in the geomagnetic filed via the mechanism of stochastic resonance in a forced Rikitake dynamo. Based on the stochastic resonance observed in the periodically forced Rikitake dynamo, we thus suggest a common triggering for geomagnetic reversal and glacial events. Both kinds of catastrophes may result from the cyclic variation of the Earth¡¦s orbital eccentricity.

  11. Factors influencing the use of a web-based application for supporting the self-care of patients with type 2 diabetes : a longitudinal study

    NARCIS (Netherlands)

    Nijland, Nicol; van Gemert-Pijnen, Julia E.W.C.; Kelders, Saskia M.; Brandenburg, Bart J.; Seydel, Erwin R.

    2011-01-01

    Background: The take-up of eHealth applications in general is still rather low and user attrition is often high. Only limited information is available about the use of eHealth technologies among specific patient groups. Objective: The aim of this study was to explore the factors that influence the

  12. A New Method for Studying the Periodic System Based on a Kohonen Neural Network

    Science.gov (United States)

    Chen, David Zhekai

    2010-01-01

    A new method for studying the periodic system is described based on the combination of a Kohonen neural network and a set of chemical and physical properties. The classification results are directly shown in a two-dimensional map and easy to interpret. This is one of the major advantages of this approach over other methods reported in the…

  13. A comprehensive review of 46 exercise treatment studies in fibromyalgia (1988–2005

    Directory of Open Access Journals (Sweden)

    Winters-Stone Kerri

    2006-09-01

    Full Text Available Abstract The purpose of this review was to: (1 locate all exercise treatment studies of fibromyalgia (FM patients from 1988 through 2005, (2 present in tabular format the key details of each study and (3 to provide a summary and evaluation of each study for exercise and health outcomes researchers. Exercise intervention studies in FM were retrieved through Cochrane Collaboration Reviews and key word searches of the medical literature, conference proceedings and bibliographies. Studies were reviewed for inclusion using a standardized process. A table summarizing subject characteristics, exercise mode, timing, duration, frequency, intensity, attrition and outcome variables was developed. Results, conclusions and comments were made for each study. Forty-six exercise treatment studies were found with a total of 3035 subjects. The strongest evidence was in support of aerobic exercise a treatment prescription for fitness and symptom and improvement. In general, the greatest effect and lowest attrition occurred in exercise programs that were of lower intensity than those of higher intensity. Exercise is a crucial part of treatment for people with FM. Increased health and fitness, along with symptom reduction, can be expected with exercise that is of appropriate intensity, self-modified, and symptom-limited. Exercise and health outcomes researchers are encouraged to use the extant literature to develop effective health enhancing programs for people with FM and to target research to as yet understudied FM subpopulations, such as children, men, older adults, ethnic minorities and those with common comorbidities of osteoarthritis and obesity.

  14. Quantized gauge invariant periodic TDHF solutions

    International Nuclear Information System (INIS)

    Kan, K.-K.; Griffin, J.J.; Lichtner, P.C.; Dworzecka, M.

    1979-01-01

    Time-dependent Hartree-Fock (TDHF) is used to study steady state large amplitude nuclear collective motions, such as vibration and rotation. As is well known the small amplitude TDHF leads to the RPA equation. The analysis of periodicity in TDHF is not trivial because TDHF is a nonlinear theory and it is not known under what circumstances a nonlinear theory can support periodic solutions. It is also unknown whether such periodic solution, if they exist, form a continuous or a discrete set. But, these properties may be important in obtaining the energy spectrum of the collective states from the TDHF description. The periodicity and Gauge Invariant Periodicity of solutions are investigated for that class of models whose TDHF solutions depend on time through two parameters. In such models TDHF supports a continuous family of periodic solutions, but only a discrete subset of these is gauge invariant. These discrete Gauge Invariant Periodic solutions obey the Bohr-Summerfeld quantization rule. The energy spectrum of the Gauge Invariant Periodic solutions is compared with the exact eigenergies in one specific example

  15. Six-month low level chlorine dioxide gas inhalation toxicity study with two-week recovery period in rats

    Directory of Open Access Journals (Sweden)

    Akamatsu Akinori

    2012-02-01

    Full Text Available Abstract Background Chlorine dioxide (CD gas has a potent antimicrobial activity at extremely low concentration and may serve as a new tool for infection control occupationally as well as publicly. However, it remains unknown whether the chronic exposure of CD gas concentration effective against microbes is safe. Therefore, long-term, low concentration CD gas inhalation toxicity was studied in rats as a six-month continuous whole-body exposure followed by a two-week recovery period, so as to prove that the CD gas exposed up to 0.1 ppm (volume ratio is judged as safe on the basis of a battery of toxicological examinations. Methods CD gas at 0.05 ppm or 0.1 ppm for 24 hours/day and 7 days/week was exposed to rats for 6 months under an unrestrained condition with free access to chow and water in a chamber so as to simulate the ordinary lifestyle in human. The control animals were exposed to air only. During the study period, the body weight as well as the food and water consumptions were recorded. After the 6-month exposure and the 2-week recovery period, animals were sacrificed and a battery of toxicological examinations, including biochemistry, hematology, necropsy, organ weights and histopathology, were performed. Results Well regulated levels of CD gas were exposed throughout the chamber over the entire study period. No CD gas-related toxicity sign was observed during the whole study period. No significant difference was observed in body weight gain, food and water consumptions, and relative organ weight. In biochemistry and hematology examinations, changes did not appear to be related to CD gas toxicity. In necropsy and histopathology, no CD gas-related toxicity was observed even in expected target respiratory organs. Conclusions CD gas up to 0.1 ppm, exceeding the level effective against microbes, exposed to whole body in rats continuously for six months was not toxic, under a condition simulating the conventional lifestyle in human.

  16. Physical studies of asteroids. XXXII. Rotation periods and UBVRI-colours for selected asteroids

    Science.gov (United States)

    Piironen, J.; Lagerkvist, C.-I.; Erikson, A.; Oja, T.; Magnusson, P.; Festin, L.; Nathues, A.; Gaul, M.; Velichko, F.

    1998-03-01

    We present lightcurves of selected asteroids. Most of the asteroids were included to obtain refined spin periods. Enhanced periods were determined for 11 Parthenope, 306 Unitas and 372 Palma. We confirmed the spin periods of 8 Flora, 13 Egeria, 71 Niobe, 233 Asterope, 291 Alice, 409 Aspasia, 435 Ella and 512 Taurinensis. We determined also BV-colours for most of the included asteroids and UBVRI-colours for a total of 22 asteroids.

  17. Dental Hygiene Student Attrition.

    Science.gov (United States)

    Young, Lynda J.; Fellows, Avis L.

    1981-01-01

    A study to determine differences between graduating and withdrawing students in the University of Minnesota Dental Hygiene program is discussed. The identification of differences may prove useful in the selection process for future classes through identification of students likely to complete their education. (MLW)

  18. Brain function and structure and risk for incident diabetes: The Atherosclerosis Risk in Communities Study.

    Science.gov (United States)

    Bancks, Michael P; Alonso, Alvaro; Gottesman, Rebecca F; Mosley, Thomas H; Selvin, Elizabeth; Pankow, James S

    2017-12-01

    Diabetes is prospectively associated with cognitive decline. Whether lower cognitive function and worse brain structure are prospectively associated with incident diabetes is unclear. We analyzed data for 10,133 individuals with cognitive function testing (1990-1992) and 1212 individuals with brain magnetic resonance imaging (1993-1994) from the Atherosclerosis Risk in Communities cohort. We estimated hazard ratios for incident diabetes through 2014 after adjustment for traditional diabetes risk factors and cohort attrition. Higher level of baseline cognitive function was associated with lower risk for diabetes (per 1 standard deviation, hazard ratio = 0.94; 95% confidence interval = 0.90, 0.98). This association did not persist after accounting for baseline glucose level, case ascertainment methods, and cohort attrition. No association was observed between any brain magnetic resonance imaging measure and incident diabetes. This is one of the first studies to prospectively evaluate the association between both cognitive function and brain structure and the incidence of diabetes. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  19. Study on The Extended Range Weather Forecast of Low Frequency Signal Based on Period Analysis Method

    Science.gov (United States)

    Li, X.

    2016-12-01

    Although many studies have explored the MJO and its application for weather forecasting, low-frequency oscillation has been insufficiently studied for the extend range weather forecasting over middle and high latitudes. In China, low-frequency synoptic map is a useful tool for meteorological operation department to forecast extend range weather. It is therefore necessary to develop objective methods to serve the need for finding low-frequency signal, interpretation and application of this signal in the extend range weather forecasting. In this paper, method of Butterworth band pass filter was applied to get low-frequency height field at 500hPa from 1980 to 2014 by using NCEP/NCAR daily grid data. Then period analysis and optimal subset regression methods were used to process the low frequency data of 150 days before the first forecast day and extend the low frequency signal of 500hPa low-frequency high field to future 30 days in the global from June to August during 2011-2014. Finally, the results were test. The main results are as follows: (1) In general, the fitting effect of low frequency signals of 500hPa low-frequency height field by period analysis in the northern hemisphere was better than that in the southern hemisphere, and was better in the low latitudes than that in the high latitudes. The fitting accuracy gradually reduced with the increase of forecast time length, which tended to be stable during the late forecasting period. (2) The fitting effects over the 6 key regions in China showed that except filtering result over Xinjiang area in the first 10 days and 30 days, filtering results over the other 5 key regions throughout the whole period have passed reliability test with level more than 95%. (3) The center and scope of low and high low frequency systems can be fitted well by using the methods mentioned above, which is consist with the corresponding use of the low-frequency synoptic map for the prediction of the extended period. Application of the

  20. Positive periodic solutions of delayed periodic Lotka-Volterra systems

    International Nuclear Information System (INIS)

    Lin Wei; Chen Tianping

    2005-01-01

    In this Letter, for a general class of delayed periodic Lotka-Volterra systems, we prove some new results on the existence of positive periodic solutions by Schauder's fixed point theorem. The global asymptotical stability of positive periodic solutions is discussed further, and conditions for exponential convergence are given. The conditions we obtained are weaker than the previously known ones and can be easily reduced to several special cases

  1. Pathways in STEM: Factors affecting the retention and attrition of talented men and women from the STEM pipeline

    Science.gov (United States)

    Heilbronner, Nancy N.

    Many men and women who are talented in science, technology, engineering, and/or mathematics (STEM) choose not to pursue undergraduate majors or careers in these fields. To develop talents in STEM, educators must understand the factors that contribute to an individual's retention in STEM domains, as well as the factors that act as barriers to success, such as the role that gender plays in the underrepresentation of women in certain STEM fields (e.g., computer science and engineering) and changes in recent decades in the process of selecting STEM majors and careers. The purpose of this study was to explore the influences that guide decisions related to the selection of majors and occupations during high school, post-secondary education, and early careers. Survey methodology was used to explore the perceptions of 360 Science Talent Search (STS) semifinalists and finalists during the years 1987-1989 and 1997-1999, and quantitative procedures were used to analyze the data. A majority (74.2%) of STS participants majored in a STEM field in college, and most (68.6%) currently work in a STEM field. A greater percentage of men selected computer science, engineering, physics, and mathematics majors, and a greater percentage of women selected biological science and chemistry. Belief in one's ability to achieve in STEM was a predictor of STEM majors in college and STEM concentrations in graduate school, but differences were found between men's and women's self-efficacy in STEM during high school and in college, as women had lower self-efficacy. Sex was a predictor of STEM majors in college, but perceived quality of academic courses was not. STEM majors also reported more satisfaction with their STEM courses in high school and college than non-STEM majors. In a departure from the results of previous research, the reasons that men and women selected occupations were similar, as were the reasons they chose to leave or not to enter STEM. The most frequently cited reason for

  2. Almost periodic Hamiltonians: an algebraic approach

    International Nuclear Information System (INIS)

    Bellissard, J.

    1981-07-01

    We develop, by analogy with the study of periodic potential, an algebraic theory for almost periodic hamiltonians, leading to a generalized Bloch theorem. This gives rise to results concerning the spectral measures of these operators in terms of those of the corresponding Bloch hamiltonians

  3. A study on the competitiveness improvement of the OPR1000 through reduction of the construction period

    International Nuclear Information System (INIS)

    Lee, Deuck Soo

    2009-02-01

    Current world's nuclear power plant markets change will provide variety opportunities to the Korean nuclear power plant industries. The economic competitiveness is the most significant issue to utilize the forthcoming 'Renaissance of Nuclear Power' as a chance of exporting OPR1000. To improve the competitiveness of the OPR1000, the capital cost which is the key factor of the generating cost of the nuclear power plant should be reduced. Reduction of the construction period is more important than the design improvement or facility change regarding capital cost perspectives. The aim of this study, therefore, is to introduce the parallel installation method for reducing the construction period to achieve the economic competitiveness. The parallel installation path was selected among critical paths by analyzing the construction schedules of the nuclear power plants built in Korea. Reactor Coolant Loop Installation and Reactor Vessel Internal Installation were selected for the parallel installation method in this study. Conventional installation method installs reactor vessel internal after finishing reactor coolant loop installation. Therefore it needs about twenty (20) months from the reactor vessel settings to the completion of the reactor vessel internal installation. The parallel installation methodology proposed in this study can reduce the construction period about two (2) months by installing reactor vessel internals in parallel with the welding process of the cross-over leg between the steam generator and the reactor coolant pump. ANSYS Codes was utilized to show the deformation impacts on the reactor vessel caused by the shrinkage force imposed by the welding process of the cross-over leg. The code analysis results lead the deformation impact is negligible. And it confirms the parallel installation of the reactor vessel internal with the cross-over leg can be applied for the OPR1000 construction. The economic improvement by the parallel installation was also

  4. Periodic testing in operative action

    International Nuclear Information System (INIS)

    Larm, T.

    2005-01-01

    Periodic testing forms a remarkable part of the regular work tasks of the shift crew. Testing is generally carried out beside the daily monitoring and control work. Even remarkable plant related differences may occur in the procedures and routines used in periodic testing. The goal is still always the same, to regularly ensure that the systems and equipment are in working order according to their design. This presentation studies with examples the execution and scope of periodic testing as well as the routines and procedures used in the testing in Loviisa power plant. The presentation is based on the testing procedures of Loviisa power plant and the aim is not to compare them to the procedures of other plants. The scope of periodic testing has increased and the routines and procedures have been developed as the operation experience has increased. The assessment of the need of periodic testing and the consideration of the practical execution possibilities should be a part of the plant's planning phase as a part of the planning process. (orig.)

  5. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  6. Magnetosphere-ionosphere coupling during periods of extended high auroral activity: a case study

    Directory of Open Access Journals (Sweden)

    S. Liléo

    2008-03-01

    Full Text Available Results are presented from a case study of a plasma boundary crossing by the Cluster spacecraft during an extended period of high auroral activity. The boundary between the magnetotail lobe region of the Southern Hemisphere and the plasma sheet boundary layer, was characterized by intense electric and magnetic field variations, structured upward accelerated ion beams, narrow-scale large field-aligned Poynting fluxes directed upward away from the ionosphere, and a relatively sharp plasma density gradient. The observations are shown to be consistent with the concept of a multi-layered boundary with temporal and/or spatial variations in the different layers. H+ and O+ ion beams are seen to be accelerated upwards both by means of a field-aligned electric field and by magnetic pumping caused by large-amplitude and low-frequency electric field fluctuations. The peak energy of the ion beams may here be used as a diagnostic tool for the temporal evolution of the spatial structures, since the temporal changes occur on a time-scale shorter than the times-of-flight of the detected ion species. The case study also shows the boundary region to be mainly characterized by a coupling of the detected potential structures to the low ionosphere during the extended period of high auroral activity, as indicated by the intense field-aligned Poynting fluxes directed upward away from the ionosphere.

  7. Emergence periodicity of Phlebotomus argentipes annandale and brunetti (Diptera: psychodidae): A laboratory study.

    Science.gov (United States)

    Dinesh, D S; Singh, A; Kumar, V; Kesari, S; Kumar, A J; Kishore, K; Roy, S P; Bhattacharya, S K; Das, P

    2009-12-01

    Phlebotomus argentipes Annandale and Brunetti (Diptera: Psychodidae) is the vector for visceral leishmaniasis in India. The aspects of its biology such as feeding and man vector contact are associated with emergence periodicity of the adult. Hence, the present study was made to find out the actual emergence period of P. argentipes. Wild caught P. argentipes were confined in the rearing pots inside laboratory. The newly emerged adults were collected at hourly intervals and released in to separate polythene bags and were held at 4°C till death. Sand flies were segregated sex-wise after the death under a microscope. The emergence of adult was observed throughout the day. However, the male preferred dawn emergence and the female the dusk. Two peaks of emergence were found in a day; first one in the morning (0900h) and the second one in the evening (1800h). The ratio of both sexes was found to be about equal. The emergence of adult was found to be 77% out of total eggs laid, which was completed within 7-10 days from the 1st day of emergence under laboratory conditions (25°C to 31°C and 70% to 75% relative humidity). This study has important bearings to find out the actual time for personal protection against biting of sand flies to prevent the transmission of Kala-azar.

  8. David's Understanding of Functions and Periodicity

    Science.gov (United States)

    Gerson, Hope

    2008-01-01

    This is a study of David, a senior enrolled in a high school precalculus course. David's understandings of functions and periodicity was explored, through clinical interviews and contextualized through classroom observations. Although David's precalculus class was traditional his understanding of periodic functions was unconventional David engaged…

  9. From Periodic Properties to a Periodic Table Arrangement

    Science.gov (United States)

    Besalú, Emili

    2013-01-01

    A periodic table is constructed from the consideration of periodic properties and the application of the principal components analysis technique. This procedure is useful for objects classification and data reduction and has been used in the field of chemistry for many applications, such as lanthanides, molecules, or conformers classification.…

  10. PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

    International Nuclear Information System (INIS)

    Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

    2015-01-01

    Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods

  11. Soil decontamination at Rocky Flats

    International Nuclear Information System (INIS)

    Olsen, R.L.; Hayden, J.A.; Alford, C.E.; Kochen, R.L.; Stevens, J.R.

    1979-01-01

    A soils decontamination project was initiated, to remove actinides from soils at Rocky Flats. Wet screening, attrition scrubbing with Calgon at high pH, attrition scrubbing at low pH, and cationic flotation were investigated. Pilot plant studies were carried out. Conceptual designs have been generated for mounting the process in semi-trailers

  12. Empowerment, Leadership, and Teachers' Intentions to Stay in or Leave the Profession or Their Schools in North Carolina Charter Schools

    Science.gov (United States)

    Ndoye, Abdou; Imig, Scott R.; Parker, Michele A.

    2010-01-01

    Teacher attrition and migration plague many American schools. The situation is even more dire in charter schools across the country. On average, teacher attrition is 15 to 40% higher in charter schools than in traditional schools. This study examined the relationships among teacher empowerment, school leadership, and intentions to stay in or leave…

  13. Caustic Injury In Adults – A Study For 3 Year Period

    Directory of Open Access Journals (Sweden)

    Radenkova-Saeva J.

    2016-10-01

    Full Text Available The aim of the study is to present the results of a 3-year clinico-epidemiological investigation of caustic injury in adults. The study includes 43 patients with acute corrosive ingestion, hospitalized in the Toxicology Clinic, University Hospital “N. I. Pirogov”, Sofia, Bulgaria, for the period 01.01. 2010-31.12.2012. The methods used include: clinical observation and examination, clinical laboratory, imaging, and psychiatric methods and tests. 43 patients between the ages of 22 and 82 with acute corrosive ingestions have been observed. Eleven were male (25.6% and 32 female (74.4%. All ingestions were intentional. Alkaline agents were used by all of the patients. The severity of poisonings varied from moderate to extremely severe. Different complications were seen in 82% of the cases - severe bleeding, perforation, fistula or/and stricture formation. Two of the patients have undergone surgical intervention - coloesophagoplastic - and have recovered completely. The motivation in different age groups was also studied. Psychiatric comorbidity occurred in patients as depressive and schizoaffective disorder, as well as existential crises. Acute corrosive ingestions by alkaline agents cause severe pathology. The severity and complex character of the injuries require good coordination between different medical specialists.

  14. On Flipping First-Semester Calculus: A Case Study

    Science.gov (United States)

    Petrillo, Joseph

    2016-01-01

    High failure rates in calculus have plagued students, teachers, and administrators for decades, while science, technology, engineering, and mathematics programmes continue to suffer from low enrollments and high attrition. In an effort to affect this reality, some educators are "flipping" (or inverting) their classrooms. By flipping, we…

  15. A short leucocyte telomere length is associated with development of insulin resistance

    DEFF Research Database (Denmark)

    Verhulst, Simon; Dalgård, Christine; Labat, Carlos

    2016-01-01

    AIMS/HYPOTHESIS: A number of studies have shown that leucocyte telomere length (LTL) is inversely associated with insulin resistance and type 2 diabetes mellitus. The aim of the present longitudinal cohort study, utilising a twin design, was to assess whether shorter LTL predicts insulin resistance...... and insulin resistance over an average of 12 years were performed in a subset of the Registry consisting of 338 (184 monozygotic and 154 dizygotic) same-sex twin pairs. RESULTS: Age at baseline examination was 37.4 ± 9.6 (mean ± SD) years. Baseline insulin resistance was not associated with age......-dependent changes in LTL (attrition) over the follow-up period, whereas baseline LTL was associated with changes in insulin resistance during this period. The shorter the LTL at baseline, the more pronounced was the increase in insulin resistance over the follow-up period (p 

  16. Study of building typology of school constructed during the Dutch Colonial Period in Indonesia. Case study of Hoogere Burgerschool (HBS) in Bandung

    Science.gov (United States)

    Sarwo Wibowo, Arif

    2018-03-01

    Bandung is one of the most important colonial cities in Indonesia. In the early 20th century the capital city of Dutch East-Indies Government planned to move in Bandung. Critical infrastructures were intensively built during that period, such as streets and railways, houses, governmental buildings, train stations, hospitals and educational facilities. Besides the famous campus of Technische Hoogeschool te Bandoeng (ITB), still in the same period, several schools were also constructed. One of the most important schools was Hoogere Burgerschool in Bandung (HBS Bandung), now SMUN 3 and 5, Bandung designed by Charles Prosper Wolff Schoemaker and constructed in 1915. HBS Bandung was the fourth HBS constructed by Dutch East Indies Government, therefore became important and put itself as a reference for the later school buildings in Bandung. This study is analyzing how the architects’ frame of mind in producing this design works. Survey and direct data collecting were used to take the exact embodiment of building design. Usage and functional analysis were also used to match space and other standard used in a school building at that time. This study will give an understanding of building typology of school during the Dutch Colonial Period in Indonesia.

  17. Attractors of the periodically forced Rayleigh system

    Directory of Open Access Journals (Sweden)

    Petre Bazavan

    2011-07-01

    Full Text Available The autonomous second order nonlinear ordinary differential equation(ODE introduced in 1883 by Lord Rayleigh, is the equation whichappears to be the closest to the ODE of the harmonic oscillator withdumping.In this paper we present a numerical study of the periodic andchaotic attractors in the dynamical system associated with the generalized Rayleigh equation. Transition between periodic and quasiperiodic motion is also studied. Numerical results describe the system dynamics changes (in particular bifurcations, when the forcing frequency is varied and thus, periodic, quasiperiodic or chaotic behaviour regions are predicted.

  18. Predictors of Delayed Entry into Medical Care of Children Diagnosed with HIV Infection: Data from an HIV Cohort Study in India

    Directory of Open Access Journals (Sweden)

    Gerardo Alvarez-Uria

    2013-01-01

    Full Text Available Data about the attrition before entry into care of children diagnosed with HIV in low- or middle-income countries are scarce. The aim of this study is to describe the attrition before engagement in HIV medical care in 523 children who were diagnosed with HIV from 2007 to 2012 in a cohort study in India. The cumulative incidence of children who entered into care was 87.2% at one year, but most children who did not enter into care within one year were lost to followup. The mortality before entry into care was low (1.3% at one year and concentrated during the first three months after HIV diagnosis. Factors associated with delayed entry into care were being diagnosed after mother’s HIV diagnosis, belonging to scheduled castes, age 90 minutes from the HIV centre. Children whose parents were alive and were living in a rented house were at a higher risk of delayed entry into care than those who were living in an owned house. The results of this study can be used to improve the linkage between HIV testing and HIV care of children diagnosed with HIV in India.

  19. Multi-band photometric study of the short-period eclipsing binary GR Boo

    Science.gov (United States)

    Wang, Daimei; Zhang, Liyun; Han, Xianming L.; Lu, Hongpeng

    2017-05-01

    We present BVRI light curves with complete phase coverage for the short-period (p = 0.377day) eclipsing binary star GR Boo. We carried out the observations using the SARA 90 cm telescope located at Kitt Peak National Observatory. We obtained six new light curve minimum times. By fitting all of the available O-C minimum times, we obtained an updated ephemeris that shows the orbital period of GR Boo is decreasing at a rate of P˙ = - 2.36 ×10-7 days/year. This decrease in its period can be explained by either mass transfer from the more massive component to the less massive one, or angular momentum exchange due to magnetic activities. We also obtained a set of revised orbital parameters using the Wilson & Devinney program. And finally, we concluded that GR Boo is a contact binary with a dark spot.

  20. Topological imprint for periodic orbits

    International Nuclear Information System (INIS)

    Martín, Jesús San; Moscoso, Ma José; Gómez, A González

    2012-01-01

    The more self-crossing points an orbit has the more complex it is. We introduce the topological imprint to characterize crossing points and focus on the period-doubling cascade. The period-doubling cascade topological imprint determines the topological imprint for orbits in chaotic bands. In addition, there is a closer link between this concept and the braids studied by Lettelier et al (2000 J. Phys. A: Math. Gen. 33 1809–25). (paper)

  1. A Case Study of Behaviour and Performance of Confined or Pastured Cows During the Dry Period

    Directory of Open Access Journals (Sweden)

    Randi A. Black

    2016-07-01

    Full Text Available The objectives of this study were to determine the effect of the dry cow management system (pasture or confined on: (1 lying behaviour and activity; (2 feeding and heat stress behaviours; (3 intramammary infections, postpartum. Non-lactating Holstein cows were assigned to either deep-bedded, sand freestalls ( n = 14 or pasture ( n = 14 using rolling enrollment. At dry-off, cows were equipped with an accelerometer to determine daily lying time (h/d, lying bouts (bouts/d, steps (steps/d and divided into periods: far-off (60 to 15 d prepartum, close-up (14 to 1 d prepartum, calving (calving date and postpartum (1 to 14 d postpartum. Respiration rates were recorded once weekly from dry off to calving from 1300 to 1500 h. Feeding displacements were defined as one cow successfully displacing another from the feed bunk and were recorded once per week during the 2 h period, immediately after feeding at 800 h. Pastured cows were fed a commercial dry cow pellet during far-off and total mixed ration during close-up, with free access to hay and grazing. Freestall housed cows were fed a total mixed ration at far-off and close-up. Cows housed in freestalls were moved to a maternity pen with a mattress at commencement of labour. Pastured cows calved in pasture. After calving, all cows were commingled in a pen identical to the freestall housing treatment. Cows housed in freestalls laid down for longer during far-off and close-up periods, had fewer lying bouts during the calving period and took fewer steps throughout the study period when compared to pastured cows. Freestall housed cows experienced more displacements after feeding than did pastured cows. Respiration rates increased with an increasing temperature humidity index, more in pastured cows than in freestall housed cows. Pastured cows altered their lying behaviour and activity, suggesting a shift in time budget priorities between pastured and confined dry cows. Pastured cows also experienced less

  2. A Case Study of Behaviour and Performance of Confined or Pastured Cows During the Dry Period.

    Science.gov (United States)

    Black, Randi A; Krawczel, Peter D

    2016-07-13

    The objectives of this study were to determine the effect of the dry cow management system (pasture or confined) on: (1) lying behaviour and activity; (2) feeding and heat stress behaviours; (3) intramammary infections, postpartum. Non-lactating Holstein cows were assigned to either deep-bedded, sand freestalls ( n = 14) or pasture ( n = 14) using rolling enrollment. At dry-off, cows were equipped with an accelerometer to determine daily lying time (h/d), lying bouts (bouts/d), steps (steps/d) and divided into periods: far-off (60 to 15 d prepartum), close-up (14 to 1 d prepartum), calving (calving date) and postpartum (1 to 14 d postpartum). Respiration rates were recorded once weekly from dry off to calving from 1300 to 1500 h. Feeding displacements were defined as one cow successfully displacing another from the feed bunk and were recorded once per week during the 2 h period, immediately after feeding at 800 h. Pastured cows were fed a commercial dry cow pellet during far-off and total mixed ration during close-up, with free access to hay and grazing. Freestall housed cows were fed a total mixed ration at far-off and close-up. Cows housed in freestalls were moved to a maternity pen with a mattress at commencement of labour. Pastured cows calved in pasture. After calving, all cows were commingled in a pen identical to the freestall housing treatment. Cows housed in freestalls laid down for longer during far-off and close-up periods, had fewer lying bouts during the calving period and took fewer steps throughout the study period when compared to pastured cows. Freestall housed cows experienced more displacements after feeding than did pastured cows. Respiration rates increased with an increasing temperature humidity index, more in pastured cows than in freestall housed cows. Pastured cows altered their lying behaviour and activity, suggesting a shift in time budget priorities between pastured and confined dry cows. Pastured cows also experienced less aggression

  3. Medicine in Balkans during the Roman Period.

    Science.gov (United States)

    Baykan, Daniş

    2017-08-04

    The aim of this study is to investigate the archaeological finds to enlighten the medical methods of treatments and operations applied in Balkans during Roman Period. Some independent local and regional find groups, taken from existing publications will be grouped together and a holistic point-of-view will be taken against medicine in Balkan Geography during Roman Period. Due to basic differences it contained, the data before Roman Period are excluded. Most of Greece and Aegean Islands are also excluded since the topic selected is "Medicine of Roman Period." Greece and Aegean Islands should be evaluated in another study in connection with West Anatolia which is closer than the Balkan Geography in terms of social relations. The spread of medical tools in Balkans during Roman Period is concentrated around military garrisons, and in settlements built around military pathways, and in settlements containing an amphitheater associated with gladiators. This spread is verified by the studies on Bulgaria in general. The data is also compatible with the assertion suggesting that the amount of application of pharmaceutical treatment increases when one moves away from the military centres.

  4. Outlook on Student Retention in Higher Education University Reforms in Morocco

    Science.gov (United States)

    Mansouri, Zoulal; Moumine, Mohamed El Amine

    2017-01-01

    High student attrition rates at university have become one of the most challenging issues in higher education worldwide in the last five decades. Moroccan universities are no exception. At-risk students drop out of studies for a plethora of reasons, and the attrition rate is increasing despite the efforts made in education reforms carried out…

  5. COMPARATIVELY STUDY OF VARIETIES OF VEGETABLE COWPEA OF DIFFERENT BREEDING PERIODS IN PRIMORIYE REGION

    Directory of Open Access Journals (Sweden)

    P. A. Chebukin

    2016-01-01

    Full Text Available Varieties of Vigna unguiculata subsp. sesquipedalis (L. Verdc. draw breeders’ attention due to their valuable properties, form variation, particularly, among long asparagus beans. The climatic condition of South Far-East is favorable for the cultivation of cowpea. Introduction of the species expands the range of cultivated crops in the region. The aim of the study was to comparatively investigate the modern and local old accessions of cowpea in the field condition of Primoriye and also to select accessions studied suitable for cultivation in this region. Field experiments were carried out at Far-Eastern Experimental Station (VIR, Vladivostok in 2012-2015. Forty accessions of different breeding periods of time from VIR plant collection were assessed. Local varieties included into collection in 1920-1930, varieties selected in 1950-1980 and modern varieties developed after 2010 were significantly different by the morphometric characteristics such as length and width of leaf, bean length and weight, seed productivity per plant, period duration – from shoots to bean-filling and from shoots to bean-ripening. The productivity of green beans depended on different morphobiological traits. For varieties bred in 1950-1980, the correlation between seed and green bean productivity and the number of beans was observed. The yield of green beans was connected with bean length and width and the duration of vegetative period in modern varieties. The varieties bred in 1950-1980 were distinguished by their simultaneous maturation and early ripening, along with the balanced number of pods per plant and seed productivity. Modern varieties essentially exceeded the previously bred cultivars in pod length, yield capacity and duration of harvesting period. Local old varieties were distinguished by broad genetic variation, and were very important as a source of valuable traits. As a result of the study the varieties suitable for

  6. How important is embeddedness in predicting Australian speech-language pathologists' intentions to leave their jobs and the profession?

    Science.gov (United States)

    Heritage, Brody; Quail, Michelle; Cocks, Naomi

    2018-03-05

    This study explored the predictors of the outcomes of turnover and occupation attrition intentions for speech-language pathologists. The researchers examined the mediating effects of job satisfaction and strain on the relationship between stress and the latter outcomes. Additionally, the researchers examined the importance of embeddedness in predicting turnover intentions after accounting for stress, strain and job satisfaction. An online questionnaire was used to explore turnover and attrition intentions in 293 Australian speech-language pathologists. Job satisfaction contributed to a significant indirect effect on the stress and turnover intention relationship, however strain did not. There was a significant direct effect between stress and turnover intention after accounting for covariates. Embeddedness and the perceived availability of alternative jobs were also found to be significant predictors of turnover intentions. The mediating model used to predict turnover intentions also predicted occupation attrition intentions. The effect of stress on occupation attrition intentions was indirect in nature, the direct effect negated by mediating variables. Qualitative data provided complementary evidence to the quantitative model. The findings indicate that the proposed parsimonious model adequately captures predictors of speech-language pathologists' turnover and occupation attrition intentions. Workplaces and the profession may wish to consider these retention factors.

  7. Communications with Mars During Periods of Solar Conjunction: Initial Study Results

    Science.gov (United States)

    Morabito, D.; Hastrup, R.

    2001-07-01

    During the initial phase of the human exploration of Mars, a reliable communications link to and from Earth will be required. The direct link can easily be maintained during most of the 780-day Earth-Mars synodic period. However, during periods in which the direct Earth-Mars link encounters increased intervening charged particles during superior solar conjunctions of Mars, the resultant effects are expected to corrupt the data signals to varying degrees. The purpose of this article is to explore possible strategies, provide recommendations, and identify options for communicating over this link during periods of solar conjunctions. A significant improvement in telemetry data return can be realized by using the higher frequency 32 GHz (Ka-band), which is less susceptible to solar effects. During the era of the onset of probable human exploration of Mars, six superior conjunctions were identified from 2015 to 2026. For five of these six conjunctions, where the signal source is not occulted by the disk of the Sun, continuous communications with Mars should be achievable. Only during the superior conjunction of 2023 is the signal source at Mars expected to lie behind the disk of the Sun for about one day and within two solar radii (0. 5 deg) for about three days.

  8. A prospective cohort study to investigate cost-minimisation, of Traditional open, open fAst track recovery and laParoscopic fASt track multimodal management, for surgical patients with colon carcinomas (TAPAS study

    Directory of Open Access Journals (Sweden)

    van Duivendijk Peter

    2010-06-01

    Full Text Available Abstract Background The present developments in colon surgery are characterized by two innovations: the introduction of the laparoscopic operation technique and fast recovery programs such as the Enhanced Recovery After Surgery (ERAS recovery program. The Tapas-study was conceived to determine which of the three treatment programs: open conventional surgery, open 'ERAS' surgery or laparoscopic 'ERAS' surgery for patients with colon carcinomas is most cost minimizing? Method/design The Tapas-study is a three-arm multicenter prospective cohort study. All patients with colon carcinoma, eligible for surgical treatment within the study period in four general teaching hospitals and one university hospital will be included. This design produces three cohorts: Conventional open surgery is the control exposure (cohort 1. Open surgery with ERAS recovery (cohort 2 and laparoscopic surgery with ERAS recovery (cohort 3 are the alternative exposures. Three separate time periods are used in order to prevent attrition bias. Primary outcome parameters are the two main cost factors: direct medical costs (real cost price calculation and the indirect non medical costs (friction method. Secondary outcome parameters are mortality, complications, surgical-oncological resection margins, hospital stay, readmission rates, time back to work/recovery, health status and quality of life. Based on an estimated difference in direct medical costs (highest cost factor of 38% between open and laparoscopic surgery (alfa = 0.01, beta = 0.05, a group size of 3×40 = 120 patients is calculated. Discussion The Tapas-study is three-arm multicenter cohort study that will provide a cost evaluation of three treatment programs for patients with colon carcinoma, which may serve as a guideline for choice of treatment and investment strategies in hospitals. Trial registration ISRCTN44649165.

  9. Magnetosphere-ionosphere coupling during periods of extended high auroral activity: a case study

    Directory of Open Access Journals (Sweden)

    S. Liléo

    2008-03-01

    Full Text Available Results are presented from a case study of a plasma boundary crossing by the Cluster spacecraft during an extended period of high auroral activity. The boundary between the magnetotail lobe region of the Southern Hemisphere and the plasma sheet boundary layer, was characterized by intense electric and magnetic field variations, structured upward accelerated ion beams, narrow-scale large field-aligned Poynting fluxes directed upward away from the ionosphere, and a relatively sharp plasma density gradient.

    The observations are shown to be consistent with the concept of a multi-layered boundary with temporal and/or spatial variations in the different layers. H+ and O+ ion beams are seen to be accelerated upwards both by means of a field-aligned electric field and by magnetic pumping caused by large-amplitude and low-frequency electric field fluctuations. The peak energy of the ion beams may here be used as a diagnostic tool for the temporal evolution of the spatial structures, since the temporal changes occur on a time-scale shorter than the times-of-flight of the detected ion species.

    The case study also shows the boundary region to be mainly characterized by a coupling of the detected potential structures to the low ionosphere during the extended period of high auroral activity, as indicated by the intense field-aligned Poynting fluxes directed upward away from the ionosphere.

  10. Effect of Tai Chi Exercise on Type 2 Diabetes: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    Chwan-Li Shen Dr.

    2007-01-01

    Full Text Available This feasibility study investigated the effects of Tai Chi, a mind-body exercise, on management of Type 2 diabetes mellitus. A total of 25 subjects (20–70 years were recruited to participate in two 60-minute instructed Tai Chi exercise sessions each week for 12 weeks. The primary outcome measures (physiological variables were hemoglobin A 1 C (HbA1c taken at baseline and after 12 weeks of intervention, and self-reported fasting blood glucose level measured at baseline, 3, 6, 9, and 12 weeks of intervention. The secondary outcome measures (psychosocial variables were Diabetes Quality of Life Questionnaire (Diabetes-39 and Exercise Self-Efficacy administered at baseline and 12 weeks. A semi-structured interview was conducted at the end of the study (week 12. Paired t -tests was employed to determine all pre- and post-intervention measurement changes, while individual growth curves were generated to show changes in fasting blood glucose levels during the study period. A rather high attrition rate of 48% was observed among the participants. The data showed no significant effect of Tai Chi on HbA1c and self-reported fasting blood glucose, although there seemed to be a trend of lowered HbA1c. Analysis of subjects’ response suggested a positive experience for those who completed the intervention.

  11. Musculoskeletal symptoms and job strain among nursing personnel: a study over a three year period.

    Science.gov (United States)

    Josephson, M; Lagerström, M; Hagberg, M; Wigaeus Hjelm, E

    1997-01-01

    OBJECTIVES: To examine the variation of symptoms from the neck, shoulders, and back over a three year period among female nursing personnel and the relation between job strain and musculoskeletal symptoms. METHODS: At a county hospital the female nursing personnel answered a questionnaire at baseline and then once a year over a period of three years. There were 565, 553, 562, and 419 subjects who answered the questionnaire at the first, second, third, and fourth survey, respectively. Of the study group, 285 nursing personnel answered the questionnaire on four occasions. Ongoing symptoms of the neck, shoulders, and back were assessed by means of a 10 point (0-9) scale with the verbal end points "no symptoms" and "very intense symptoms." Cases were defined as nursing personnel reporting ongoing symptoms, score > 6, from at least one of the body regions. For assessments of job strain, a Swedish version of Karasek and Theorell's model was used. RESULTS: Of the 285 subjects, 13% were defined as cases at all four assessments, and 46% varied between cases and not cases during the study period. In the repeated cross sectional surveys the estimated rate ratio (RR) for being a case was between 1.1 and 1.5 when comparing the group with job strain and the group without job strain. For the combination of job strain and perceived high physical exertion the estimated RR was between 1.5 and 2.1. When the potential risk factors were assessed one, two, or three years before the assessment of symptoms the estimated RR for becoming a case was between 1.4 and 2.2 when comparing the group with job strain and the group without job strain. CONCLUSION: Almost half of the healthcare workers varied between being a case and not, over a three year period. The analysis indicated that job strain is a risk factor for musculoskeletal symptoms and that the risk is higher when it is combined with perceived high physical exertion. PMID:9423583

  12. Attractors for discrete periodic dynamical systems

    Science.gov (United States)

    John E. Franke; James F. Selgrade

    2003-01-01

    A mathematical framework is introduced to study attractors of discrete, nonautonomous dynamical systems which depend periodically on time. A structure theorem for such attractors is established which says that the attractor of a time-periodic dynamical system is the unin of attractors of appropriate autonomous maps. If the nonautonomous system is a perturbation of an...

  13. Entropy method of measuring and evaluating periodicity of quasi-periodic trajectories

    Science.gov (United States)

    Ni, Yanshuo; Turitsyn, Konstantin; Baoyin, Hexi; Junfeng, Li

    2018-06-01

    This paper presents a method for measuring the periodicity of quasi-periodic trajectories by applying discrete Fourier transform (DFT) to the trajectories and analyzing the frequency domain within the concept of entropy. Having introduced the concept of entropy, analytical derivation and numerical results indicate that entropies increase as a logarithmic function of time. Periodic trajectories typically have higher entropies, and trajectories with higher entropies mean the periodicities of the motions are stronger. Theoretical differences between two trajectories expressed as summations of trigonometric functions are also derived analytically. Trajectories in the Henon-Heiles system and the circular restricted three-body problem (CRTBP) are analyzed with the indicator entropy and compared with orthogonal fast Lyapunov indicator (OFLI). The results show that entropy is a better tool for discriminating periodicity in quasiperiodic trajectories than OFLI and can detect periodicity while excluding the spirals that are judged as periodic cases by OFLI. Finally, trajectories in the vicinity of 243 Ida and 6489 Golevka are considered as examples, and the numerical results verify these conclusions. Some trajectories near asteroids look irregular, but their higher entropy values as analyzed by this method serve as evidence of frequency regularity in three directions. Moreover, these results indicate that applying DFT to the trajectories in the vicinity of irregular small bodies and calculating their entropy in the frequency domain provides a useful quantitative analysis method for evaluating orderliness in the periodicity of quasi-periodic trajectories within a given time interval.

  14. Period-dependent source rupture behavior of the 2011 Tohoku earthquake estimated by multi period-band Bayesian waveform inversion

    Science.gov (United States)

    Kubo, H.; Asano, K.; Iwata, T.; Aoi, S.

    2014-12-01

    Previous studies for the period-dependent source characteristics of the 2011 Tohoku earthquake (e.g., Koper et al., 2011; Lay et al., 2012) were based on the short and long period source models using different method. Kubo et al. (2013) obtained source models of the 2011 Tohoku earthquake using multi period-bands waveform data by a common inversion method and discussed its period-dependent source characteristics. In this study, to achieve more in detail spatiotemporal source rupture behavior of this event, we introduce a new fault surface model having finer sub-fault size and estimate the source models in multi period-bands using a Bayesian inversion method combined with a multi-time-window method. Three components of velocity waveforms at 25 stations of K-NET, KiK-net, and F-net of NIED are used in this analysis. The target period band is 10-100 s. We divide this period band into three period bands (10-25 s, 25-50 s, and 50-100 s) and estimate a kinematic source model in each period band using a Bayesian inversion method with MCMC sampling (e.g., Fukuda & Johnson, 2008; Minson et al., 2013, 2014). The parameterization of spatiotemporal slip distribution follows the multi-time-window method (Hartzell & Heaton, 1983). The Green's functions are calculated by the 3D FDM (GMS; Aoi & Fujiwara, 1999) using a 3D velocity structure model (JIVSM; Koketsu et al., 2012). The assumed fault surface model is based on the Pacific plate boundary of JIVSM and is divided into 384 subfaults of about 16 * 16 km^2. The estimated source models in multi period-bands show the following source image: (1) First deep rupture off Miyagi at 0-60 s toward down-dip mostly radiating relatively short period (10-25 s) seismic waves. (2) Shallow rupture off Miyagi at 45-90 s toward up-dip with long duration radiating long period (50-100 s) seismic wave. (3) Second deep rupture off Miyagi at 60-105 s toward down-dip radiating longer period seismic waves then that of the first deep rupture. (4) Deep

  15. Epidemiology of injuries in elite taekwondo athletes: two Olympic periods cross-sectional retrospective study

    Science.gov (United States)

    Altarriba-Bartes, Albert; Drobnic, Franchek; Til, Lluís; Malliaropoulos, Nikolaos; Montoro, José Bruno; Irurtia, Alfredo

    2014-01-01

    Objective Taekwondo injuries differ according to the characteristics of the athletes and the competition. This analytical cross-sectional retrospective cohort study aimed to describe reported taekwondo injuries and to determine the prevalence, characteristics and possible risk factors for injuries sustained by athletes of the Spanish national team. In addition, we compared each identified risk factor—age, weight category, annual quarter, injury timing and competition difficulty level—with its relation to injury location and type. Settings Injury occurrences in taekwondo athletes of the Spanish national team during two Olympic periods at the High Performance Centre in Barcelona were analysed. Participants 48 taekwondo athletes (22 male, 26 female; age range 15–31 years) were studied; 1678 injury episodes occurred. Inclusion criteria were: (1) having trained with the national taekwondo group for a minimum of one sports season; (2) being a member of the Spanish national team. Results Independently of sex or Olympic period, the anatomical sites with most injury episodes were knee (21.3%), foot (17.0%), ankle (12.2%), thigh (11.4%) and lower leg (8.8%). Contusions (29.3%) and cartilage (17.6%) and joint (15.7%) injuries were the prevalent types of injury. Chronological age, weight category and annual quarter can be considered risk factors for sustaining injuries in male and female elite taekwondists according to their location and type (p≤0.001). Conclusions This study provides epidemiological information that will help to inform future injury surveillance studies and the development of prevention strategies and recommendations to reduce the number of injuries in taekwondo competition. PMID:24531455

  16. Adolescent pregnancy in a Greek public hospital during a six-year period (2000-2005)--a retrospective study.

    Science.gov (United States)

    Panagopoulos, P; Salakos, N; Bakalianou, K; Davou, E; Iavazzo, C; Paltoglou, G; Liapis, A

    2008-10-01

    Adolescent pregnancy constitutes a multidimensional social problem in modern Greece. The purpose of this study was to investigate the trends of teenage childbearing and to determine the relationship between the incidence of teenage pregnancy and immigrant status of the mother. This is a retrospective correlational study. The birth registry of the hospital was examined for a 6-year period, from January 2000 to December 2005. Information about the age and nationality of the mothers was collected. The hospital under investigation is Tzaneio Hospital, a public general hospital that provides health services to the residents of Piraeus, a large municipality next to Athens. During the study period 4628 women gave birth at Tzaneio Hospital, among which 349 (7.54%) were under the age of 19. The study hypothesis, that adolescent childbearing prevails among immigrant population, was confirmed (P Greek government, health professionals, and sexuality educators should all work together in order to confront this problem.

  17. Infant twin mortality and hospitalisations after the perinatal period - a prospective cohort study from Guinea-Bissau

    DEFF Research Database (Denmark)

    Bjerregaard-Andersen, M; Biering-Sørensen, S; Gomes, G M

    2014-01-01

    OBJECTIVE: To examine mortality and hospitalisations among infant twins and singletons after the perinatal period in Guinea-Bissau. METHODS: The study was conducted from September 2009 to November 2012 by the Bandim Health Project (BHP). Newborn twins and unmatched singleton controls were included...

  18. Vertebrate fauna of the Roman period, migrations period and Medieval period in Vojvodina (Serbia

    Directory of Open Access Journals (Sweden)

    Radmanović Darko P.

    2014-01-01

    Full Text Available Based on current published and unpublished research results, a total of 16 vertebrate species members of mammal (Mammalia, bird (Aves and osteichthyes (Osteichthyes classes have been registered at 11 archaeological sites from the Roman Period in Vojvodina. Mammals dominate with 12 species and one genus, birds are present with 3 species, and osteichthyes with one. From the Migration Period, at 9 sites, 22 vertebrate species have been registered, of which 13 species and one genus of mammals, 4 species and one genus of birds, and 5 species from the Osteichthyes class. At 8 sites from the Medieval Period, 16 vertebrate species have been registered. Mammals are the most numerous class with 10 species and one genus, while birds are present with 4 species and one genus. Furthermore, two species of osteichthyes have also been registered.

  19. Commuting periodic operators and the periodic Wigner function

    International Nuclear Information System (INIS)

    Zak, J

    2004-01-01

    Commuting periodic operators (CPO) depending on the coordinate x-hat and the momentum p-hat operators are defined. The CPO are functions of the two basic commuting operators exp(i x-hat 2π/a) and exp(i/h p-hat a), with a being an arbitrary constant. A periodic Wigner function (PWF) w(x, p) is defined and it is shown that it is applicable in a normal expectation value calculation to the CPO, as done in the original Wigner paper. Moreover, this PWF is non-negative everywhere, and it can therefore be interpreted as an actual probability distribution. The PWF w(x, p) is shown to be given as an expectation value of the periodic Dirac delta function in the phase plane. (letter to the editor)

  20. Significance of acceleration period in a dynamic strength testing study.

    Science.gov (United States)

    Chen, W L; Su, F C; Chou, Y L

    1994-06-01

    The acceleration period that occurs during isokinetic tests may provide valuable information regarding neuromuscular readiness to produce maximal contraction. The purpose of this study was to collect the normative data of acceleration time during isokinetic knee testing, to calculate the acceleration work (Wacc), and to determine the errors (ERexp, ERwork, ERpower) due to ignoring Wacc during explosiveness, total work, and average power measurements. Seven male and 13 female subjects attended the test by using the Cybex 325 system and electronic stroboscope machine for 10 testing speeds (30-300 degrees/sec). A three-way ANOVA was used to assess gender, direction, and speed factors on acceleration time, Wacc, and errors. The results indicated that acceleration time was significantly affected by speed and direction; Wacc and ERexp by speed, direction, and gender; and ERwork and ERpower by speed and gender. The errors appeared to increase when testing the female subjects, during the knee flexion test, or when speed increased. To increase validity in clinical testing, it is important to consider the acceleration phase effect, especially in higher velocity isokinetic testing or for weaker muscle groups.