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Sample records for black-white population longitudinal

  1. Bogalusa Heart Study: a long-term community study of a rural biracial (Black/White) population.

    Science.gov (United States)

    Berenson, G S

    2001-11-01

    The Bogalusa Heart Study, a long-term population study with a continued relationship with a community, addresses the problem of capacity building in minority health research. The study was originally funded as a Specialized Center of Research-Arteriosclerosis (SCOR-A) by the National Heart Lung and Blood Institute (NHLBI). These centers were to conduct research on atherosclerosis, coronary artery disease (CAD), hypertension, diabetes mellitus, and complications of cardiovascular-renal disease as the major causes of deaths in the United States. From earlier research on atherosclerosis, we became interested in the underlying characteristics in early life that would eventually lead to clinical morbidity and mortality from heart disease. An observation at autopsy showed the degree of atherosclerotic involvement in human aortas, from young to older individuals (Figure 1). For example, at age 40 years, marked individual variability occurred in the severity and involvement with atherosclerotic disease. Some individuals showed very little disease, while almost 70% of the surface was diseased in others. Further studies on arterial wall matrix showed aortas from young individuals varied with the extent of disease and its chemical composition. This background stimulated an interest in studying children for early clinical evidence of major adult heart diseases. The Bogalusa Heart Study was begun in 1972 as an epidemiology study of cardiovascular risk factors in children and adolescents; it eventually evolved into observations of young adults. Bogalusa, LA, is a biracial (black/white) rural community 70 miles north of New Orleans, comparable to many other communities in southeastern United States.

  2. The Black- White Earnings Gap

    Science.gov (United States)

    Christensen, Sandra; Bernard, Keith

    1974-01-01

    Using projected labor force data (race, sex, and education) nondiscriminatory and discriminatory black-white occupational patterns and earnings ratios are defined to the year 2000. Rather than realistic estimates, the projections are designed as standards to measure progress in eliminating racial discrimination in the labor market. (EA)

  3. Educational Achievement and Black-White Inequality. Statistical Analysis Report.

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    Jacobson, Jonathan; Olsen, Cara; Rice, Jennifer King; Sweetland, Stephen

    This study explored relationships between black-white differences in educational achievement and black-white differences in various educational and economic outcomes. Three data sets examined the extent to which black-white differences in labor market outcomes, in educational attainment, and in mathematics and reading achievement were present for…

  4. Education and black-white interracial marriage.

    Science.gov (United States)

    Gullickson, Aaron

    2006-11-01

    This article examines competing theoretical claims regarding how an individual's education will affect his or her likelihood of interracial marriage. I demonstrate that prior models of interracial marriage have failed to adequately distinguish the joint and marginal effects of education on interracial marriage and present a model capable of distinguishing these effects. I test this model on black-white interracial marriages using 1980, 1990, and 2000 U.S. census data. The results reveal partial support for status exchange theory within black male-white female unions and strong isolation of lower-class blacks from the interracial marriage market. Structural assimilation theory is not supported because the educational attainment of whites is not related in any consistent fashion to the likelihood of interracial marriage. The strong isolation of lower-class blacks from the interracial marriage market has gone unnoticed in prior research because of the failure of prior methods to distinguish joint and marginal effects.

  5. An examination of black/white differences in the rate of age-related mortality increase

    Directory of Open Access Journals (Sweden)

    Andrew Fenelon

    2013-09-01

    Full Text Available BACKGROUND The rate of mortality increase with age among adults is typically used as a measure of the rate of functional decline associated with aging or senescence. While black and white populations differ in the level of mortality, mortality also rises less rapidly with age for blacks than for whites, leading to the well-known black/white mortality "crossover". OBJECTIVE This paper investigates black/white differences in the rate of mortality increase with age for major causes of death in order to examine the factors responsible for the black/white crossover. METHODS The analysis considers two explanations for the crossover: selective survival and age misreporting. Mortality is modeled using a Gompertz model for 11 causes of death from ages 50-84 among blacks and whites by sex. RESULTS Mortality increases more rapidly with age for whites than for blacks for nearly all causes of death considered. The all-cause mortality rate of mortality increase is nearly two percentage points higher for whites. The analysis finds evidence for both selective survival and age misreporting, although age misreporting is a more prominent explanation among women. CONCLUSIONS The black/white mortality crossover reflects large differences in the rate of age-related mortality increase. Instead of reflecting the impact of specific causes of death, this pattern exists across many disparate disease conditions, indicating the need for a broad explanation.

  6. Black-White Health Inequalities in Canada.

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    Veenstra, Gerry; Patterson, Andrew C

    2016-02-01

    Little is known about Black-White health inequalities in Canada or the applicability of competing explanations for them. To address this gap, we used nine cycles of the Canadian Community Health Survey to analyze multiple health outcomes in a sample of 3,127 Black women, 309,720 White women, 2,529 Black men and 250,511 White men. Adjusting for age, marital status, urban/rural residence and immigrant status, Black women and men were more likely than their White counterparts to report diabetes and hypertension, Black women were less likely than White women to report cancer and fair/poor mental health and Black men were less likely than White men to report heart disease. These health inequalities persisted after controlling for education, household income, smoking, physical activity and body-mass index. We conclude that high rates of diabetes and hypertension among Black Canadians may stem from experiences of racism in everyday life, low rates of heart disease and cancer among Black Canadians may reflect survival bias and low rates of fair/poor mental health among Black Canadian women represent a mental health paradox similar to the one that exists for African Americans in the United States.

  7. Family identity: black-white interracial family health experience.

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    Byrd, Marcia Marie; Garwick, Ann Williams

    2006-02-01

    The purpose of this interpretive descriptive study was to describe how eight Black-White couples with school-aged children constructed their interracial family identity through developmental transitions and interpreted race to their children. Within and across-case data analytic strategies were used to identify commonalities and variations in how Black men and White women in couple relationships formed their family identities over time. Coming together was the core theme described by the Black-White couples as they negotiated the process of forming a family identity. Four major tasks in the construction of interracial family identity emerged: (a) understanding and resolving family of origin chaos and turmoil, (b) transcending Black-White racial history, (c) articulating the interracial family's racial standpoint, and (d) explaining race to biracial children across the developmental stages. The findings guide family nurses in promoting family identity formation as a component of family health within the nurse-family partnership with Black-White mixed-race families.

  8. The Black-White achievement gap: Do state policies matter?

    Directory of Open Access Journals (Sweden)

    Henry I. Braun

    2006-03-01

    Full Text Available A longstanding issue in American education is the gap in academic achievement between majority and minority students. The goal of this study is to accumulate and evaluate evidence on the relationship between state education policies and changes in the Black-White achievement gap, while addressing some of the methodological issues that have led to differences in interpretations of earlier findings. To that end, we consider the experiences of ten states that together enroll more than forty percent of the nation's Black students. We estimate the trajectories of Black student and White student achievement on the NAEP 8th grade mathematics assessment over the period 1992 to 2000, and examine the achievement gap at three levels of aggregation: the state as a whole, groups of schools (strata within a state defined by the SES level of the student population, and within schools within a stratum within a state. From 1992 to 2000, at every level of aggregation, mean achievement rose for both Black students and White students. However, for most states the achievement gaps were large and changed very little at every level of aggregation. The gaps are pervasive, profound and persistent. There is substantial heterogeneity among states in the types of policies they pursued, as well as the coherence and consistency of those policies during the period 1988-1998. We find that states' overall policy rankings (based on our review of the data correlate moderately with their record in improving Black student achievement but are somewhat less useful in predicting their record with respect to reducing the achievement gaps. States' rankings on commitment to teacher quality correlate almost as well as did the overall policy ranking. Thus, state reform efforts are a blunt tool, but a tool nonetheless. Our findings are consistent with the following recommendations: states' reform efforts should be built on broad-based support and buffered as much as possible from changes in

  9. The effect of school quality on black-white health differences: evidence from segregated southern schools.

    Science.gov (United States)

    Frisvold, David; Golberstein, Ezra

    2013-12-01

    This study assesses the effect of black-white differences in school quality on black-white differences in health in later life resulting from the racial convergence in school quality for cohorts born between 1910 and 1950 in southern states with segregated schools. Using data from the 1984-2007 National Health Interview Surveys linked to race-specific data on school quality, we find that reductions in the black-white gap in school quality led to modest reductions in the black-white gap in disability.

  10. Black-white differences in infectious disease mortality in the United States

    NARCIS (Netherlands)

    J.H. Richardus (Jan Hendrik); A.E. Kunst (Anton)

    2001-01-01

    textabstractOBJECTIVES: This study determined the degree to which Black-White differences in infectious disease mortality are explained by income and education and the extent to which infectious diseases contribute to Black-White differences in all-cause mortality. METHODS: A sampl

  11. The Measured Black-White Wage Gap among Women Is Too Small.

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    Neal, Derek

    2004-01-01

    Existing work suggests that black-white gaps in potential wages are much larger among men than women and further that black-white differences in patterns of female labor supply are unimportant. However, panel data on wages and income sources demonstrate that the modal young black woman who does not engage in market work is a single mother…

  12. Explaining Black-White Disparity in Maltreatment: Poverty, Female-Headed Families, and Urbanization

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    Schuck, Amie M.

    2005-01-01

    The purpose of the current study was to assess a structural level explanation of racial disparity in child maltreatment. Using data from Florida counties (1998-2001) and the 2000 census, the effects of poverty, concentrated poverty, and female-headed families in poverty on Black, White, and the difference between Black-White rates of child…

  13. Black-White Differences in Sex and Contraceptive Use Among Young Women.

    Science.gov (United States)

    Kusunoki, Yasamin; Barber, Jennifer S; Ela, Elizabeth J; Bucek, Amelia

    2016-10-01

    This study examines black-white and other sociodemographic differences in young women's sexual and contraceptive behaviors, using new longitudinal data from a weekly journal-based study of 1,003 18- to 19-year-old women spanning 2.5 years. We investigate hypotheses about dynamic processes in these behaviors during early adulthood in order to shed light on persisting racial differences in rates of unintended pregnancies in the United States. We find that net of other sociodemographic characteristics and adolescent experiences with sex and pregnancy, black women spent less time in relationships and had sex less frequently in their relationships than white women, but did not differ in the number of relationships they formed or in their frequency or consistency of contraceptive use within relationships. Black women were more likely to use less effective methods for pregnancy prevention (e.g., condoms) than white women, who tended to use more effective methods (e.g., oral contraceptives). And although the most effective method for pregnancy prevention-long-acting reversible contraception (LARC)-was used more often by black women than white women, LARC use was low in both groups. In addition, black women did not differ from white women in their number of discontinuations or different methods used and had fewer contraceptive method switches. Further, we find that net of race and adolescent experiences with sex and pregnancy, women from more-disadvantaged backgrounds had fewer and longer (and thus potentially more serious) relationships, used contraception less frequently (but not less consistently), and used less effective methods (condoms) than women from more-advantaged backgrounds.

  14. Incarceration and Black-White inequality in Homeownership: A state-level analysis.

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    Schneider, Daniel; Turney, Kristin

    2015-09-01

    Rising incarceration rates in the United States, as well as the concentration of incarceration among already marginalized individuals, has led some scholars to suggest that incarceration increases economic inequality among American men. But little is known about the consequences of incarceration for wealth, about incarceration's contribution to Black-White disparities in wealth, or about the broader effects of incarceration on communities. In this article, we use state-level panel data (from 1985 to 2005) to examine the relationship between incarceration rates and the Black-White gap in homeownership, a distinct and important measure of wealth. Results, which are robust to an array of model specifications and robustness checks, show that incarceration rates diminish homeownership rates among Blacks and, in doing so, widen Black-White inequalities in homeownership. Therefore, the findings suggest that the consequences of incarceration extend beyond the offender and may increase inequality in household wealth.

  15. Permanent Income and the Black-White Test Score Gap. NBER Working Paper No. 17610

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    Rothstein, Jesse; Wozny, Nathan

    2011-01-01

    Analysts often examine the black-white test score gap conditional on family income. Typically only a current income measure is available. We argue that the gap conditional on permanent income is of greater interest, and we describe a method for identifying this gap using an auxiliary data set to estimate the relationship between current and…

  16. Black-White Biracial Students in American Schools: A Review of the Literature

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    Williams, Rhina Fernandes

    2009-01-01

    With increasing numbers of students who identify as Black and White multiracial and with the persistence of the Black-White test score gap, the necessity for research regarding these students' educational experiences cannot be understated. To date, research in this area has been scarce. The purpose of this review is to synthesize the available…

  17. Are Black-White Differences in Females' Body Dissatisfaction Decreasing? A Meta-Analytic Review

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    Roberts, Alan; Cash, Thomas F.; Feingold, Alan; Johnson, Blair T.

    2006-01-01

    Proponents of the sociocultural model of eating disorders have suggested that ethnic differences in body dissatisfaction may be diminishing as the thin ideal of beauty becomes more widely disseminated among minority women. In a meta-analysis, the authors examined temporal trends in Black-White differences and also examined whether these…

  18. Multiple Realities: A Relationship Narrative Approach in Therapy with Black-White Mixed-Race Clients.

    Science.gov (United States)

    Rockquemore, Kerry Ann; Laszloffy, Tracey A.

    2003-01-01

    Emerging empirical research on racial identity formation among persons with one Black and one White parent reveals that multiple identity options are possible. Presents a relational narrative approach to therapy with Black-White mixed-race clients who experience systematic invalidation of their chosen racial identity through a detailed case…

  19. Racial Context, Black Immigration and the U.S. Black/White Health Disparity

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    Read, Jen'nan Ghazal; Emerson, Michael O.

    2005-01-01

    The United States' black/white health gap is an important consequence of racial inequality. The gap is large, shows little signs of declining, and explanations have been limited by lack of theory and data. A new direction that offers potential for theoretical development is a focus on black immigrants, a group that shares the same racial status as…

  20. Pregnancy Risk among Black, White, and Hispanic Teen Girls in New York City Public Schools

    Science.gov (United States)

    Orr, Mark G.; Sackoff, Judith; Santelli, John S.

    2010-01-01

    Disparities in teen pregnancy rates are explained by different rates of sexual activity and contraceptive use. Identifying other components of risk such as race/ethnicity and neighborhood can inform strategies for teen pregnancy prevention. Data from the 2005 and 2007 New York City Youth Risk Behavior Surveys were used to model demographic differences in odds of recent sexual activity and birth control use among black, white, and Hispanic public high school girls. Overall pregnancy risk was calculated using pregnancy risk index (PRI) methodology, which estimates probability of pregnancy based on current sexual activity and birth control method at last intercourse. Factors of race/ethnicity, grade level, age, borough, and school neighborhood were assessed. Whites reported lower rates of current sexual activity (23.4%) than blacks (35.4%) or Hispanics (32.7%), and had lower predicted pregnancy risk (PRI = 5.4% vs. 9.0% and 10.5%, respectively). Among sexually active females, hormonal contraception use rates were low in all groups (11.6% among whites, 7.8% among blacks, and 7.5% among Hispanics). Compared to white teens, much of the difference in PRI was attributable to poorer contraceptive use (19% among blacks and 50% among Hispanics). Significant differences in contraceptive use were also observed by school neighborhood after adjusting for age group and race/ethnicity. Interventions to reduce teen pregnancy among diverse populations should include messages promoting delayed sexual activity, condom use and use of highly effective birth control methods. Access to long-acting contraceptive methods must be expanded for all sexually active high school students. PMID:20383750

  1. Another look at the relationship between socioeconomic factors and the black-white health benefit inequality.

    Science.gov (United States)

    Ohn, Jonathan; McMahon, Lauren; Carter, Tony

    2006-01-01

    This paper illustrates the black-white disparity in health benefit coverage and the socioeconomic variables-unemployment, income, and education. The health benefit disparity is strongly related to the disparity in underlying socioeconomic variables. Moreover, the time-series examination reveals that the change in white workers' health insurance coverage is largely determined by its year-to-year persistence and the labor market tightness (or the business cycle), while that of black workers is largely determined by the change in their earnings with a slight persistence. The effect of the change in annual earnings seems to dominate the effect of the labor market condition (unemployment rate) and other variables. Finally, although marginally significant, an increase in the attainment of higher education (college) has a positive effect on the black-white health benefit disparity.

  2. Geometries with integrable singularity -- black/white holes and astrogenic universes

    CERN Document Server

    Lukash, V N

    2011-01-01

    We briefly review the problem of generating cosmological flows of matter in GR (the genesis of universes), analyze models' shortcomings and their basic assumptions yet to be justified in physical cosmology. We propose a paradigm of cosmogenesis based on the class of spherically symmetric solutions with {\\it integrable} singularity $r=0$. They allow for geodesically complete geometries of black/white holes, which may comprise space-time regions with properties of cosmological flows.

  3. Parent and child influences on the development of a Black-White biracial identity

    OpenAIRE

    Stone, Dana J.

    2009-01-01

    In this qualitative study, the interactive process of exploring and developing shared, familial meanings about biracial identity development was investigated from the perspectives of both parents and children in Black-White multiracial families. Specifically, this study examined how monoracial parents and their biracial children describe the influence parents have on the biracial childrenâ s identity development process from the biracial individualsâ youth into adulthood. Monoracial parent...

  4. Pelvic pain after childbirth: a longitudinal population study.

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    Bjelland, Elisabeth Krefting; Owe, Katrine Mari; Pingel, Ronnie; Kristiansson, Per; Vangen, Siri; Eberhard-Gran, Malin

    2016-03-01

    In this longitudinal population study, the aims were to study associations of mode of delivery with new onset of pelvic pain and changes in pelvic pain scores up to 7 to 18 months after childbirth. We included 20,248 participants enrolled in the Norwegian Mother and Child Cohort Study (1999-2008) without preexisting pelvic pain in pregnancy. Data were obtained by 4 self-administered questionnaires and linked to the Medical Birth Registry of Norway. A total of 4.5% of the women reported new onset of pelvic pain 0 to 3 months postpartum. Compared to unassisted vaginal delivery, operative vaginal delivery was associated with increased odds of pelvic pain (adjusted odds ratio [OR]: 1.30; 95% confidence interval [CI]: 1.06-1.59). Planned and emergency cesarean deliveries were associated with reduced odds of pelvic pain (adjusted OR: 0.48; 95% CI: 0.31-0.74 and adjusted OR: 0.65; 95% CI: 0.49-0.87, respectively). Planned cesarean delivery, young maternal age, and low Symptom Checklist-8 scores were associated with low pelvic pain scores after childbirth. A history of pain was the only factor associated with increased pelvic pain scores over time (P = 0.047). We conclude that new onset of pelvic pain after childbirth was not commonly reported, particularly following cesarean delivery. Overall, pelvic pain scores were rather low at all time points and women with a history of pain reported increased pelvic pain scores over time. Hence, clinicians should follow up women with pelvic pain after a difficult childbirth experience, particularly if they have a history of pain.

  5. Educational Disparity and the Persistence of the Black-White Wage Gap in the U.S.

    Science.gov (United States)

    O'Gorman, Melanie

    2010-01-01

    This paper examines the relationship between contemporary racial inequality of schooling and the black-white wage gap in the U.S. In particular I ask: what policies would be effective at reducing the black-white wage gap in the U.S.? In order to address this question, I develop a model of human capital accumulation in which agents differ by race.…

  6. BLACK & WHITE

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Residential building work in LiukengVillage, Le’an County, JiangxiProvince, was started in theSouthern Tang Dynasty (937 - 942AD). Today, there are still more than300 buildings in the village that werebuilt in the Ming Dynasty (1368 -1644) and the Qing Dynasty (1644 -1911). This is one part of southernChina where history is wellpreserved.

  7. 'Population laboratories' or 'laboratory populations'? Making sense of the Baltimore Longitudinal Study of Aging, 1965-1987

    NARCIS (Netherlands)

    Moreira, Tiago; Palladino, Paolo

    2011-01-01

    Interest among historians, philosophers and sociologists of science in population-based biomedical research has focused on the randomised controlled trial to the detriment of the longitudinal study, the temporally extended, serial observation of individuals residing in the same community. This is pe

  8. When Gray Matters More than Black or White: The Schooling Experiences of Black-White Biracial Students

    Science.gov (United States)

    Williams, Rhina Maria Fernandes

    2013-01-01

    Although research is scant, there is a growing interest in the manifestation of the racial and cultural context on the schooling of biracial students. The purpose of this qualitative research study was to explore the schooling experiences of 10 Black-White biracial students. Specifically, the goals of the study were to (a) identify the factors…

  9. Is the Black-White Achievement Gap a Public Sector Effect? An Examination of Student Achievement in the Third Grade

    Science.gov (United States)

    Simms, Kathryn

    2012-01-01

    Prior research has suggested private school education in middle school and high school as a solution for the Black-White achievement gap. However, more recent research calls this solution into question. Additionally, research increasingly implicates third grade as being of preeminent importance in driving students' subsequent academic achievement.…

  10. Harming the Best: How Schools Affect the Black-White Achievement Gap. NBER Working Paper No. 14211

    Science.gov (United States)

    Hanushek, Eric A.; Rivkin, Steven G.

    2008-01-01

    Sizeable achievement differences by race appear in early grades, but substantial uncertainty exists about the impact of school quality on the black-white achievement gap and particularly about its evolution across different parts of the achievement distribution. Texas administrative data show that the overall growth in the achievement gap between…

  11. Sleep Problems in Children with Autism Spectrum Problems: A Longitudinal Population-Based Study

    Science.gov (United States)

    Sivertsen, Borge; Posserud, Maj-Britt; Gillberg, Christopher; Lundervold, Astri J.; Hysing, Mari

    2012-01-01

    This study examined the prevalence and chronicity of sleep problems in children who manifest problems believed to be typical of Autism Spectrum Disorders (ASD). Using data from a longitudinal total population study, symptoms of ASD, insomnia and potential explanatory factors were assessed at ages 7-9 and 11-13. Children were included in a group…

  12. Population income and longitudinal trends in living kidney donation in the United States.

    Science.gov (United States)

    Gill, Jagbir; Dong, Jianghu; Gill, John

    2015-01-01

    Living kidney donation is declining in the United States. We examined longitudinal trends in living donation as a function of median household income and donor relation to assess the effect of financial barriers on donation in a changing economic environment. The zip code-level median household income of all 71,882 living donors was determined by linkage to the 2000 US Census. Longitudinal changes in the rate of donation were determined in income quintiles between 1999 and 2004, when donations were increasing, and between 2005 and 2010, when donations were declining. Rates were adjusted for population differences in age, sex, race, and ESRD rate using multilevel linear regression models. Between 1999 and 2004, the rate of growth in living donation per million population was directly related to income, increasing progressively from the lowest to highest income quintile, with annualized changes of 0.55 (95% confidence interval [95% CI], 0.14 to 1.05) for Q1 and 1.77 (95% CI, 0.66 to 2.77) for Q5 (Pincome with longitudinal changes also varied by donor relationship. In conclusion, changes in living donation in the past decade varied by median household income, resulting in increased disparities in donation between low- and high-income populations. These findings may inform public policies to support living donation during periods of economic volatility.

  13. Affective Valence, Stimulus Attributes, and P300: Color vs. Black/White and Normal vs. Scrambled Images

    Science.gov (United States)

    Cano, Maya E.; Class, Quetzal A.; Polich, John

    2009-01-01

    Pictures from the International Affective Picture System (IAPS) were selected to manipulate affective valence (unpleasant, neutral, pleasant) while keeping arousal level the same. The pictures were presented in an oddball paradigm, with a visual pattern used as the standard stimulus. Subjects pressed a button whenever a target was detected. Experiment 1 presented normal pictures in color and black/white. Control stimuli were constructed for both the color and black/white conditions by randomly rearranging 1 cm square fragments of each original picture to produce a “scrambled” image. Experiment 2 presented the same normal color pictures with large, medium, and small scrambled condition (2, 1, and 0.5 cm squares). The P300 event-related brain potential demonstrated larger amplitudes over frontal areas for positive compared to negative or neutral images for normal color pictures in both experiments. Attenuated and nonsignificant valence effects were obtained for black/white images. Scrambled stimuli in each study yielded no valence effects but demonstrated typical P300 topography that increased from frontal to parietal areas. The findings suggest that P300 amplitude is sensitive to affective picture valence in the absence of stimulus arousal differences, and that stimulus color contributes to ERP valence effects. PMID:18708099

  14. Education and Alcohol Consumption among Older Americans; Black-White Differences

    Directory of Open Access Journals (Sweden)

    Shervin eAssari

    2016-04-01

    Full Text Available Abstract:Purpose: Although the link between education and alcohol consumption is known, limited information exists on racial differences in this link. We conducted the current study to test Black- White differences in the association between education and alcohol consumption among older adults in the United States. Methods: This cross-sectional survey enrolled 1,493 Black (n=734 and White (n=759 older adults (age 66 or more in United States. Data came from the Religion, Aging, and Health Survey, 2001. Race, demographics, socio-economics, and alcohol consumption were measured. Independent variable was education level. Outcome was alcohol consumption. Race was the focal moderator. Logistic regression was used for data analysis. Results: Education was positively associated with ever drinking in the pooled sample. Race, however, interacted with education level on drinking, suggesting a smaller effect of education on drinking for Blacks compared to Whites. Among Whites, high school graduation and college graduation were associated with increased odds of ever drinking, net of covariates. Among Blacks, high school graduation but not college graduation was associated with ever drinking. Conclusion: Blacks and Whites differ in how socio-economic status (i.e. education shapes behaviors health behaviors (i.e. drinking. How race modifies consequences and correlates of social determinants of health is not yet clear. College graduation may result in the same level of change to the social network and income of race group members. Lower effect of education on health of Blacks may be due to the structural role of race and racism that has resulted in lower job availability and pay for Blacks.

  15. New evidence of increased risk of rhinitis in subjects with COPD: a longitudinal population study

    Science.gov (United States)

    Bergqvist, Joel; Andersson, Anders; Olin, Anna-Carin; Murgia, Nicola; Schiöler, Linus; Bove, Mogens; Hellgren, Johan

    2016-01-01

    Background The aim of this population-based study was to investigate the risk of developing noninfectious rhinitis (NIR) in subjects with chronic obstructive pulmonary disease (COPD). Materials and methods This is a longitudinal population-based study comprising 3,612 randomly selected subjects from Gothenburg, Sweden, aged 25–75 years. Lung function was measured at baseline with spirometry and the included subjects answered a questionnaire on respiratory symptoms. At follow-up, the subjects answered a questionnaire with a response rate of 87%. NIR was defined as symptoms of nasal obstruction, nasal secretion, and/or sneezing attacks without having a cold, during the last 5 years. COPD was defined as a spirometry ratio of forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) 40 years. Smoking, atopy, and occupational exposure to gas, fumes, or dust were also associated with new-onset NIR. COPD, smoking, and atopy remained individual risk factors for new-onset NIR in the logistic regression analysis. Conclusions This longitudinal population-based study of a large cohort showed that COPD is a risk factor for developing NIR. Smoking and atopy are also risk factors for NIR. The results indicate that there is a link present between upper and lower respiratory inflammation in NIR and COPD. PMID:27799760

  16. Longitudinal population-based studies of affective disorders: Where to from here?

    Directory of Open Access Journals (Sweden)

    Beard John R

    2008-09-01

    Full Text Available Abstract Background Longitudinal, population-based, research is important if we are to better characterize the lifetime patterns and determinants of affective disorders. While studies of this type are becoming increasingly prevalent, there has been little discussion about the limitations of the methods commonly used. Methods Discussion paper including a brief review of key prospective population-based studies as the basis for a critical appraisal of current approaches. Results We identified a number of common methodological weaknesses that restrict the potential of longitudinal research to characterize the diversity, prognosis, and determinants of affective disorders over time. Most studies using comprehensive diagnostic instruments have either been of relatively brief duration, or have suffered from long periods between waves. Most etiologic research has focused on first onset diagnoses, although these may be relatively uncommon after early adulthood and the burden of mental disorders falls more heavily on individuals with recurring disorders. Analysis has tended to be based on changes in diagnostic status rather than anges in symptom levels, limiting study power. Diagnoses have generally been treated as homogeneous entities and few studies have explored whether diagnostic subtypes such as atypical depression vary in their etiology or prognosis. Little research has considered whether there are distinct trajectories of symptoms over time and most has focused on individual disorders such as depression, rather than considering the relationship over time between symptoms of different affective disorders. There has also been limited longitudinal research on factors in the physical or social environment that may influence the onset, recurrence or chronicity of symptoms. Conclusion Many important, and in some respects quite basic, questions remain about the trajectory of depression and anxiety disorders over the life course and the factors that

  17. Longitudinal variability of time-location/activity patterns of population at different ages: a longitudinal study in California

    Directory of Open Access Journals (Sweden)

    Cassady Diana L

    2011-09-01

    Full Text Available Abstract Background Longitudinal time-activity data are important for exposure modeling, since the extent to which short-term time-activity data represent long-term activity patterns is not well understood. This study was designed to evaluate longitudinal variations in human time-activity patterns. Method We report on 24-hour recall diaries and questionnaires collected via the internet from 151 parents of young children (mostly under age 55, and from 55 older adults of ages 55 and older, for both a weekday and a weekend day every three months over an 18-month period. Parents also provided data for their children. The self-administrated diary and questionnaire distinguished ~30 frequently visited microenvironments and ~20 activities which we selected to represent opportunities for exposure to toxic environmental compounds. Due to the non-normal distribution of time-location/activity data, we employed generalized linear mixed-distribution mixed-effect models to examine intra- and inter-individual variations. Here we describe variation in the likelihood of and time spent engaging in an activity or being in a microenvironment by age group, day-type (weekday/weekend, season (warm/cool, sex, employment status, and over the follow-up period. Results As expected, day-type and season influence time spent in many location and activity categories. Longitudinal changes were also observed, e.g., young children slept less with increasing follow-up, transit time increased, and time spent on working and shopping decreased during the study, possibly related to human physiological changes with age and changes in macro-economic factors such as gas prices and the economic recession. Conclusions This study provides valuable new information about time-activity assessed longitudinally in three major age groups and greatly expands our knowledge about intra- and inter-individual variations in time-location/activity patterns. Longitudinal variations beyond weekly and

  18. Longitudinal Changes in Vascular Risk Markers and Mortality Rates among a Latino Population with Hypertension.

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    Pflederer, Matthew C; Long, Carlin S; Beaty, Brenda; Havranek, Edward P; Mehler, Philip S; Keniston, Angela; Krantz, Mori J

    2016-04-01

    Vascular markers such as pulse-wave velocity and carotid intima-media thickness (CIMT) might improve the prediction of incident cardiovascular disease beyond traditional risk factors. These vascular markers have not been well characterized in minority populations and might be more useful than inflammatory biomarkers. We conducted a prospective, longitudinal cohort study among hypertensive patients in an urban safety-net hospital. We evaluated inflammatory biomarkers, arterial pulse-wave velocity, and carotid intima-media thickness at baseline, 1 year, and 2 years. The primary outcome variable was CIMT. Generalized linear mixed-effects models were used to evaluate associations between CIMT and predictive variables accounting for the correlation of multiple measurements within subjects over time. For our secondary outcome, we used administrative and National Death Index data to determine all-cause death, and univariate relationships were evaluated. Among 175 subjects, 117 were Latino (67%) and 117 were female (67%). Pulse-wave velocity and CIMT regressed over time (both P <0.001) and were highly correlated (P <0.001). Only pulse-wave velocity (P=0.002) and total cholesterol (P=0.03) were associated with CIMT in time-varying covariate analysis. At a median follow-up period of 80 months, 17 of 175 subjects had died (10%). Higher baseline CIMT and pulse-wave velocity were associated with increased mortality rates (both P <0.01). No serum inflammatory marker was significantly correlated with longitudinal changes in CIMT or death. In conclusion, both arterial stiffness and preclinical carotid atherosclerosis were associated with increased mortality rates and might be useful risk-stratification markers among this minority population.

  19. New evidence of increased risk of rhinitis in subjects with COPD: a longitudinal population study

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    Bergqvist J

    2016-10-01

    Full Text Available Joel Bergqvist,1 Anders Andersson,2 Anna-Carin Olin,3 Nicola Murgia,3,4 Linus Schiöler,3 Mogens Bove,5 Johan Hellgren1 1Department of Otorhinolaryngology, Head and Neck Surgery, Institute of Clinical Sciences, 2Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, 3Department of Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; 4Department of Medicine, Section of Occupational Medicine, Respiratory Diseases and Toxicology, University of Perugia, Perugia, Italy; 5Department of ENT and Oral Maxillofacial Surgery, NU Hospital Group, Trollhättan, Sweden Background: The aim of this population-based study was to investigate the risk of developing noninfectious rhinitis (NIR in subjects with chronic obstructive pulmonary disease (COPD. Materials and methods: This is a longitudinal population-based study comprising 3,612 randomly selected subjects from Gothenburg, Sweden, aged 25–75 years. Lung function was measured at baseline with spirometry and the included subjects answered a questionnaire on respiratory symptoms. At follow-up, the subjects answered a questionnaire with a response rate of 87%. NIR was defined as symptoms of nasal obstruction, nasal secretion, and/or sneezing attacks without having a cold, during the last 5 years. COPD was defined as a spirometry ratio of forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC <0.7. Subjects who reported asthma and NIR at baseline were excluded from the study. The odds ratios for developing NIR (ie, new-onset NIR in relation to age, gender, body mass index, COPD, smoking, and atopy were calculated. Results: In subjects with COPD, the 5-year incidence of NIR was significantly increased (10.8% vs 7.4%, P=0.005 and was higher among subjects aged >40 years. Smoking, atopy, and occupational exposure to gas, fumes, or dust were also associated with new-onset NIR. COPD, smoking, and atopy remained

  20. Inconsistent self-reported mammography history: Findings from the National Population Health Survey longitudinal cohort

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    Snider Judy

    2004-11-01

    Full Text Available Abstract Background Self-reported information has commonly been used to monitor mammography utilization across populations and time periods. However, longitudinal investigations regarding the prevalence and determinants of inconsistent responses over time and the impact of such responses on population screening estimates are lacking. Methods Based on longitudinal panel data for a representative cohort of Canadian women aged 40+ years (n = 3,537 assessed in the 1994–95 (baseline and 1996–97 (follow-up National Population Health Survey (NPHS, we examined the prevalence of inconsistent self-reports of mammography utilization. Logistic regression models were used to estimate the associations between women's baseline sociodemographic and health characteristics and 2 types of inconsistent responses: (i baseline reports of ever use which were subsequently contradicted by follow-up reports of never use; and (ii baseline reports of never use which were contradicted by follow-up reports of use prior to 1994–95. Results Among women who reported having a mammogram at baseline, 5.9% (95% confidence interval (CI: 4.6–7.3% reported at follow-up that they had never had one. Multivariate logistic regression analyses showed that women with such inconsistent responses were more often outside target age groups, from low income households and less likely to report hormone replacement therapy and Pap smear use. Among women reporting never use at baseline and ever use at follow-up, 17.4% (95%CI: 11.7–23.1% reported their most recent mammogram as occurring prior to 1994–95 (baseline and such responses were more common among women aged 70+ years and those in poorer health. Conclusions Women with inconsistent responses of type (i, i.e., ever users at baseline but never users at follow-up, appeared to exhibit characteristics typical of never users of mammography screening. Although limited by sample size, our preliminary analyses suggest that type (ii

  1. Longitudinal, population-based study of racial/ethnic differences in colorectal cancer survival: impact of neighborhood socioeconomic status, treatment and comorbidity

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    Stroup Antoinette

    2007-10-01

    Full Text Available Abstract Background Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods. Methods This study evaluated the joint effects of sociodemographic factors, tumor characteristics, census-based socioeconomic status (SES, treatment, and comorbidities on survival after colorectal cancer among and within racial/ethnic groups, using the SEER-Medicare database for patients diagnosed in 1992–1996, and followed through 1999. Results Unadjusted colorectal cancer-specific mortality rates were higher among Blacks and Hispanic males than whites (relative rates (95% confidence intervals = 1.34 (1.26–1.42 and 1.16 (1.04–1.29, respectively, and lower among Japanese (0.78 (0.70–0.88. These patterns were evident for all-cause mortality, although the magnitude of the disparity was larger for colorectal cancer mortality. Adjustment for stage accounted for the higher rate among Hispanic males and most of the lower rate among Japanese. Among Blacks, stage and SES accounted for about half of the higher rate relative to Whites, and within stage III colon and stages II/III rectal cancer, SES completely accounted for the small differentials in survival between Blacks and Whites. Comorbidity did not appear to explain the Black-White differentials in colorectal-specific nor all-cause mortality, beyond stage, and treatment (surgery, radiation, chemotherapy explained a very small proportion of the Black-White difference. The fully-adjusted relative mortality rates comparing Blacks to Whites was 1.14 (1.09–1.20 for all-cause mortality and 1.21 (1.14–1.29 for colorectal cancer specific mortality. The sociodemographic, tumor, and treatment characteristics also had different impacts on mortality within racial/ethnic groups. Conclusion In this comprehensive analysis, race/ethnic-specific models revealed

  2. Postindustrial Capitalism and the Problems with Bourdieu's Social and Cultural Capital in Understanding the Black/White Achievement Gap in the United States and United Kingdom

    Science.gov (United States)

    Mocombe, Paul C.

    2015-01-01

    This hermeneutical essay demonstrates why and how Pierre Bourdieu's social reproduction theory is neither an adequate explanation for understanding praxis nor the Black/White academic achievement gap in contemporary postindustrial economies like that of the United States and the United Kingdom. The underlining hypothesis of the work is that the…

  3. Cardiovascular events in patients with atherothrombotic disease: a population-based longitudinal study in Taiwan.

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    Wen-Hsien Lee

    Full Text Available BACKGROUND: Atherothrombotic diseases including cerebrovascular disease (CVD, coronary artery disease (CAD, and peripheral arterial disease (PAD, contribute to the major causes of death in the world. Although several studies showed the association between polyvascular disease and poor cardiovascular (CV outcomes in Asian population, there was no large-scale study to validate this relationship in this population. METHODS AND RESULTS: This retrospective cohort study included patients with a diagnosis of CVD, CAD, or PAD from the database contained in the Taiwan National Health Insurance Bureau during 2001-2004. A total of 19954 patients were enrolled in this study. The atherothrombotic disease score was defined according to the number of atherothrombotic disease. The study endpoints included acute coronary syndrome (ACS, all strokes, vascular procedures, in hospital mortality, and so on. The event rate of ischemic stroke (18.2% was higher than that of acute myocardial infarction (5.7% in our patients (P = 0.0006. In the multivariate Cox regression analyses, the adjusted hazard ratios (HRs of each increment of atherothrombotic disease score in predicting ACS, all strokes, vascular procedures, and in hospital mortality were 1.41, 1.66, 1.30, and 1.14, respectively (P≦0.0169. CONCLUSIONS: This large population-based longitudinal study in patients with atherothrombotic disease demonstrated the risk of subsequent ischemic stroke was higher than that of subsequent AMI. In addition, the subsequent adverse CV events including ACS, all stroke, vascular procedures, and in hospital mortality were progressively increased as the increase of atherothrombotic disease score.

  4. Population genetics inference for longitudinally-sampled mutants under strong selection.

    Science.gov (United States)

    Lacerda, Miguel; Seoighe, Cathal

    2014-11-01

    Longitudinal allele frequency data are becoming increasingly prevalent. Such samples permit statistical inference of the population genetics parameters that influence the fate of mutant variants. To infer these parameters by maximum likelihood, the mutant frequency is often assumed to evolve according to the Wright-Fisher model. For computational reasons, this discrete model is commonly approximated by a diffusion process that requires the assumption that the forces of natural selection and mutation are weak. This assumption is not always appropriate. For example, mutations that impart drug resistance in pathogens may evolve under strong selective pressure. Here, we present an alternative approximation to the mutant-frequency distribution that does not make any assumptions about the magnitude of selection or mutation and is much more computationally efficient than the standard diffusion approximation. Simulation studies are used to compare the performance of our method to that of the Wright-Fisher and Gaussian diffusion approximations. For large populations, our method is found to provide a much better approximation to the mutant-frequency distribution when selection is strong, while all three methods perform comparably when selection is weak. Importantly, maximum-likelihood estimates of the selection coefficient are severely attenuated when selection is strong under the two diffusion models, but not when our method is used. This is further demonstrated with an application to mutant-frequency data from an experimental study of bacteriophage evolution. We therefore recommend our method for estimating the selection coefficient when the effective population size is too large to utilize the discrete Wright-Fisher model.

  5. Childhood Gender-Typed Behavior and Adolescent Sexual Orientation: A Longitudinal Population-Based Study.

    Science.gov (United States)

    Li, Gu; Kung, Karson T F; Hines, Melissa

    2017-02-20

    Lesbian and gay individuals have been reported to show more interest in other-sex, and/or less interest in same-sex, toys, playmates, and activities in childhood than heterosexual counterparts. Yet, most of the relevant evidence comes from retrospective studies or from prospective studies of clinically referred, extremely gender nonconforming children. In addition, findings are mixed regarding the relation between childhood gender-typed behavior and the later sexual orientation spectrum from exclusively heterosexual to exclusively lesbian/gay. The current study drew a sample (2,428 girls and 2,169 boys) from a population-based longitudinal study, and found that the levels of gender-typed behavior at ages 3.5 and 4.75 years, although less so at age 2.5 years, significantly and consistently predicted adolescents' sexual orientation at age 15 years, both when sexual orientation was conceptualized as 2 groups or as a spectrum. In addition, within-individual change in gender-typed behavior during the preschool years significantly related to adolescent sexual orientation, especially in boys. These results suggest that the factors contributing to the link between childhood gender-typed behavior and sexual orientation emerge during early development. Some of those factors are likely to be nonsocial, because nonheterosexual individuals appear to diverge from gender norms regardless of social encouragement to conform to gender roles. (PsycINFO Database Record

  6. Burden of diabetes mellitus estimated with a longitudinal population-based study using administrative databases.

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    Luciana Scalone

    Full Text Available OBJECTIVE: To assess the epidemiologic and economic burden of diabetes mellitus (DM from a longitudinal population-based study. RESEARCH DESIGN AND METHODS: Lombardy Region includes 9.9 million individuals. Its DM population was identified through a data warehouse (DENALI, which matches with a probabilistic linkage demographic, clinical and economic data of different Healthcare Administrative databases. All individuals, who, during the year 2000 had an hospital discharge with a IDC-9 CM code 250.XX, and/or two consecutive prescriptions of drugs for diabetes (ATC code A10XXXX within one year, and/or an exemption from co-payment healthcare costs specific for DM, were selected and followed up to 9 years. We calculated prevalence, mortality and healthcare costs (hospitalizations, drugs and outpatient examinations/visits from the National Health Service's perspective. RESULTS: We identified 312,223 eligible subjects. The study population (51% male had a mean age of 66 (from 0.03 to 105.12 years at the index date. Prevalence ranged from 0.4% among subjects aged ≤45 years to 10.1% among those >85 years old. Overall 43.4 deaths per 1,000 patients per year were estimated, significantly (p<0.001 higher in men than women. Overall, 3,315€/patient-year were spent on average: hospitalizations were the cost driver (54.2% of total cost. Drugs contributed to 31.5%, outpatient claims represented 14.3% of total costs. Thirty-five percent of hospital costs were attributable to cerebro-/cardiovascular reasons, 6% to other complications of DM, and 4% to DM as a main diagnosis. Cardiovascular drugs contributed to 33.5% of total drug costs, 21.8% was attributable to class A (16.7% to class A10 and 4.3% to class B (2.4% to class B01 drugs. CONCLUSIONS: Merging different administrative databases can provide with many data from large populations observed for long time periods. DENALI shows to be an efficient instrument to obtain accurate estimates of burden of

  7. Labor market segmentation and relative black/white teenage birth rates.

    Science.gov (United States)

    Mccrate, E

    1990-01-01

    "Teenage mothers typically have lower educational attainment than other women. Most observers have argued that this is a major reason for their greater risk of poverty. This article takes the opposite view: that circumstances associated with poverty contribute to a greater likelihood of teenage childbearing. In particular, poor educational quality and the chances of secondary sector employment are more common for black women, regardless of their age at first birth. Hence the payoffs to education may be quite low for these women, which may be the reason for early motherhood. This argument is presented in terms of segmented labor market theory. Data to support it is presented from the [U.S.] National Longitudinal Survey of Youth. Other common explanations of teenage motherhood are critiqued."

  8. Improving the Rank Precision of Population Health Measures for Small Areas with Longitudinal and Joint Outcome Models.

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    Jessica K Athens

    Full Text Available The University of Wisconsin Population Health Institute has published the County Health Rankings since 2010. These rankings use population-based data to highlight health outcomes and the multiple determinants of these outcomes and to encourage in-depth health assessment for all United States counties. A significant methodological limitation, however, is the uncertainty of rank estimates, particularly for small counties. To address this challenge, we explore the use of longitudinal and pooled outcome data in hierarchical Bayesian models to generate county ranks with greater precision.In our models we used pooled outcome data for three measure groups: (1 Poor physical and poor mental health days; (2 percent of births with low birth weight and fair or poor health prevalence; and (3 age-specific mortality rates for nine age groups. We used the fixed and random effects components of these models to generate posterior samples of rates for each measure. We also used time-series data in longitudinal random effects models for age-specific mortality. Based on the posterior samples from these models, we estimate ranks and rank quartiles for each measure, as well as the probability of a county ranking in its assigned quartile. Rank quartile probabilities for univariate, joint outcome, and/or longitudinal models were compared to assess improvements in rank precision.The joint outcome model for poor physical and poor mental health days resulted in improved rank precision, as did the longitudinal model for age-specific mortality rates. Rank precision for low birth weight births and fair/poor health prevalence based on the univariate and joint outcome models were equivalent.Incorporating longitudinal or pooled outcome data may improve rank certainty, depending on characteristics of the measures selected. For measures with different determinants, joint modeling neither improved nor degraded rank precision. This approach suggests a simple way to use existing

  9. From Kindergarten readiness to fourth-grade assessment: longitudinal analysis with linked population data.

    Science.gov (United States)

    Lloyd, Jennifer E V; Hertzman, Clyde

    2009-01-01

    Early child development (ECD)--the development of physical, social-emotional, and language-cognitive capacities in the early years--is a foundation of health, well-being, learning, and behaviour across the life course. Consequently, the capacity to monitor ECD is an important facet of a modern society. This capacity is achieved by having in place an ongoing flow of high-quality information on the state of early child development, its determinants, and long-term developmental outcomes. Accordingly, there remains a considerable need for research that merges community-centred, longitudinal, and linked-data approaches to monitoring child development. The current paper addresses this need by introducing one method of summarising and quantifying the developmental trajectories of British Columbian children at the neighbourhood- or district-level: computing the Community Index of Child Development (CICD) for each geographic area. A simple index that describes change in children's developmental trajectories at the aggregate level, the CICD is computable because of our capacity to conduct individual-level linkage of two population data sets: the Early Development Instrument (EDI), a holistic measure of children's readiness for school which is administered at Kindergarten, and the British Columbia Ministry of Education's Foundation Skills Assessment (FSA), a Grade 4 measure of academic skills. In this paper, we demonstrate: (a) wide variation in the CICDs according to the children's district of residence in Kindergarten; (b) an association of the CICDs with an indicator of the socioeconomic character of the neighbourhoods; and (c) contrasting patterns of neighbourhood convergence and divergence in two different school districts--such that, in some areas, children from high vulnerability neighbourhoods tend to catch up between Kindergarten and Grade 4 whereas, in other areas, they tend to fall further behind.

  10. Can insomnia in pregnancy predict postpartum depression? A longitudinal, population-based study.

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    Signe K Dørheim

    Full Text Available BACKGROUND: Insomnia and depression are strongly interrelated. This study aimed to describe changes in sleep across childbirth, and to evaluate whether insomnia in pregnancy is a predictor of postpartum depression. METHODS: A longitudinal, population-based study was conducted among perinatal women giving birth at Akershus University Hospital, Norway. Women received questionnaires in weeks 17 and 32 of pregnancy and eight weeks postpartum. This paper presents data from 2,088 of 4,662 women with complete data for insomnia and depression in week 32 of pregnancy and eight weeks postpartum. Sleep times, wake-up times and average sleep durations were self-reported. The Bergen Insomnia Scale (BIS was used to measure insomnia. The Edinburgh Postnatal Depression Scale (EPDS was used to measure depressive symptoms. RESULTS: After delivery, sleep duration was reduced by 49 minutes (to 6.5 hours, and mean sleep efficiency was reduced from 84% to 75%. However, self-reported insomnia scores (BIS improved from 17.2 to 15.4, and the reported prevalence of insomnia decreased from 61.6% to 53.8%. High EPDS scores and anxiety in pregnancy, fear of delivery, previous depression, primiparity, and higher educational level were risk factors for both postpartum insomnia and depression. Insomnia did not predict postpartum depression in women with no prior history of depression, whereas women who recovered from depression had residual insomnia. LIMITATIONS: Depression and insomnia were not verified by clinical interviews. Women with depressive symptoms were less likely to remain in the study. CONCLUSIONS: Although women slept fewer hours at night after delivery compared to during late pregnancy, and reported more nights with nighttime awakenings, their self-reported insomnia scores improved, and the prevalence of insomnia according to the DSM-IV criteria decreased. Insomnia in pregnancy may be a marker for postpartum recurrence of depression among women with previous

  11. Decomposing Black-White Disparities in Heart Disease Mortality in the United States, 1973-2010: An Age-Period-Cohort Analysis.

    Science.gov (United States)

    Kramer, Michael R; Valderrama, Amy L; Casper, Michele L

    2015-08-15

    Against the backdrop of late 20th century declines in heart disease mortality in the United States, race-specific rates diverged because of slower declines among blacks compared with whites. To characterize the temporal dynamics of emerging black-white racial disparities in heart disease mortality, we decomposed race-sex-specific trends in an age-period-cohort (APC) analysis of US mortality data for all diseases of the heart among adults aged ≥35 years from 1973 to 2010. The black-white gap was largest among adults aged 35-59 years (rate ratios ranged from 1.2 to 2.7 for men and from 2.3 to 4.0 for women) and widened with successive birth cohorts, particularly for men. APC model estimates suggested strong independent trends across generations ("cohort effects") but only modest period changes. Among men, cohort-specific black-white racial differences emerged in the 1920-1960 birth cohorts. The apparent strength of the cohort trends raises questions about life-course inequalities in the social and health environments experienced by blacks and whites which could have affected their biomedical and behavioral risk factors for heart disease. The APC results suggest that the genesis of racial disparities is neither static nor restricted to a single time scale such as age or period, and they support the importance of equity in life-course exposures for reducing racial disparities in heart disease.

  12. Evidence for a persistent, environment-dependent and deteriorating subtype of subclinical psychotic experiences : a 6-year longitudinal general population study

    NARCIS (Netherlands)

    Wigman, J.T.; van, Winkel R.; Raaijmakers, Q.A.; Ormel, J.; Verhulst, F.C.; Reijneveld, S.A.; van, Os J.; Vollebergh, W.A.

    2011-01-01

    Background. Research suggests that subclinical psychotic experiences during adolescence represent the behavioral expression of liability for psychosis. Little is known, however, about the longitudinal trajectory of liability in general population samples. Method. Growth mixture modeling was used to

  13. Last hired, first fired? Black-white unemployment and the business cycle.

    Science.gov (United States)

    Couch, Kenneth A; Fairlie, Robert

    2010-02-01

    Studies have tested the claim that blacks are the last hired during periods of economic growth and the first fired in recessions by examining the movement of relative unemployment rates over the business cycle. Any conclusion drawn from this type of analysis must be viewed as tentative because cyclical movements in the underlying transitions into and out of unemployment are not examined. Using Current Population Survey data matched across adjacent months from 1989-2004, this article provides the first detailed examination of labor market transitions for prime-age black and white men to test the last hired, first fired hypothesis. Considerable evidence is presented that blacks are the first fired as the business cycle weakens. However no evidence is found that blacks are the last hired. Instead, blacks appear to be initially hired from the ranks of the unemployed early in the business cycle and later are drawn from nonparticipation. The narrowing of the racial unemployment gap near the peak of the business cycle is driven by a reduction in the rate of job loss for blacks rather than increases in hiring.

  14. Approaches in methodology for population-based longitudinal study on neuroprotective model for healthy longevity (TUA) among Malaysian Older Adults.

    Science.gov (United States)

    Shahar, Suzana; Omar, Azahadi; Vanoh, Divya; Hamid, Tengku Aizan; Mukari, Siti Zamratol Mai-Sarah; Din, Normah Che; Rajab, Nor Fadilah; Mohammed, Zainora; Ibrahim, Rahimah; Loo, Won Hui; Meramat, Asheila; Kamaruddin, Mohd Zul Amin; Bagat, Mohamad Fazdillah; Razali, Rosdinom

    2016-12-01

    A number of longitudinal studies on aging have been designed to determine the predictors of healthy longevity, including the neuroprotective factors, however, relatively few studies included a wide range of factors and highlighted the challenges faced during data collection. Thus, the longitudinal study on neuroprotective model for healthy longevity (LRGS TUA) has been designed to prospectively investigate the magnitude of cognitive decline and its risk factors through a comprehensive multidimensional assessment comprising of biophysical health, auditory and visual function, nutrition and dietary pattern and psychosocial aspects. At baseline, subjects were interviewed for their status on sociodemographic, health, neuropsychological test, psychosocial and dietary intake. Subjects were also measured for anthropometric and physical function and fitness. Biospecimens including blood, buccal swap, hair and toenail were collected, processed and stored. A subsample was assessed for sensory function, i.e., vision and auditory. During follow-up, at 18 and 36 months, most of the measurements, along with morbidity and mortality outcomes will be collected. The description of mild cognitive impairment, successful aging and usual aging process is presented here. A total 2322 respondents were recruited in the data analysis at baseline. Most of the respondents were categorized as experiencing usual aging (73 %), followed by successful aging (11 %) and mild cognitive impairment (16 %). The LRGS TUA study is the most comprehensive longitudinal study on aging in Malaysia, and will contribute to the understanding of the aging process and factors associated with healthy aging and mental well-being of a multiethnic population in Malaysia.

  15. Factors influencing exclusive breastfeeding among Iranian mothers: A longitudinal population-based study

    OpenAIRE

    Mohsen Saffari; Amir H. Pakpour; Hui Chen

    2017-01-01

    Background: Exclusive breastfeeding (EBF) contributes to the health and survival of the newborns. Many factors influence the EBF behavior. This study aimed to identify the determinant factors in order to improve the practice of EBF among Iranian mothers. Methods: A longitudinal study was carried out in 1445 mothers with newborns in Qazvin city, Iran (September 2015-March 2016). Demographic variables as well as the constructs of theory of planned behavior (TBP) were measu...

  16. Black, White and Grey

    Directory of Open Access Journals (Sweden)

    Nasrin Nooshfar

    2011-05-01

    Full Text Available Background/Objective: Development of science and"nart achieved with saving independence, separation"nclassification and studying their details. The other hand"nis combination of these to create a new world with"nwide dimensions and take a place to human needs."nMaterials and Methods: Our attempt is to make"nhealth-care places pleasant and attractive for patients."nWe offer best services, but they are not comfortable"nand happy in these places. They are afraid of the staff,"nequipment and the environment. For this purpose"nwe mixed the brightness and darkness of radiologic"nimages with white and black photographs or paintings"ncomplementary to create analog artistic images that"ncould be converted to digital printing by DICOM"ninterfaces on hard copies."nConclusion: Fear, pictures a bad memory in the"npatient's mind forever. We mixed radiology and"nimaging with photography as a science and art mixture"nto conflict with these problems, it is more effective in"nchildren who are suffering from social and known"ndiseases and can not adapt themselves with their"nsituations. This could create a good memory between"nthe human body image and sentimental experience."nIn the literature, printed radiologic images were used"nas fine art on glass and paper, metal and flowers were"nemployed to mix.* *Wim Delvoye (born 1965 ,Wervik"nand Steven N.Meyers and Merille Raikes

  17. Predictors of Disordered Eating in Adolescence and Young Adulthood: A Population-Based, Longitudinal Study of Females and Males in Norway

    Science.gov (United States)

    Abebe, Dawit Shawel; Torgersen, Leila; Lien, Lars; Hafstad, Gertrud S.; von Soest, Tilmann

    2014-01-01

    We investigated longitudinal predictors for disordered eating from early adolescence to young adulthood (12-34 years) across gender and different developmental phases among Norwegian young people. Survey data from a population-based sample were collected at four time points (T) over a 13-year time span. A population-based sample of 5,679 females…

  18. Global Longitudinal Strain by Echocardiography Predicts Long-Term Risk of Cardiovascular Morbidity and Mortality in a Low-Risk General Population

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Biering-Sørensen, Sofie Reumert; Olsen, Flemming Javier

    2017-01-01

    BACKGROUND: Global longitudinal strain (GLS) is prognostic of adverse cardiovascular outcomes in various patient populations, but the prognostic utility of GLS for long-term cardiovascular morbidity and mortality in the general population is unknown. METHODS AND RESULTS: A total of 1296 participa...

  19. Quality of life among prostate cancer patients : A prospective longitudinal population-based study

    NARCIS (Netherlands)

    Schaake, Wouter; de Groot, Martijn; Krijnen, Wim P.; Langendijk, Johannes A.; van den Bergh, Alfons C. M.

    2013-01-01

    Purpose: To investigate the course of quality of life (QoL) among prostate cancer patients treated with external beam radiotherapy and to compare the results with QoL of a normal age-matched reference population. Patients and methods: The study population was composed of 227 prostate cancer patients

  20. A population-based longitudinal study of risk factors for suicide attempts in major depressive disorder.

    Science.gov (United States)

    Bolton, James M; Pagura, Jina; Enns, Murray W; Grant, Bridget; Sareen, Jitender

    2010-10-01

    No longitudinal study has examined risk factors for future suicide attempts in major depressive disorder in a nationally representative sample. The objective of this study was to investigate baseline sociodemographic characteristics, comorbid mental disorders, specific depressive symptoms, and previous suicidal behavior as potential risk factors for suicide attempts at 3 years follow-up. Data came from the national epidemiologic survey on alcohol and related conditions (NESARC), a large nationally representative longitudinal survey of mental illness in adults [Wave 1 (2001-2002); Wave 2 (2004-2005) n=34,653]. Logistic regression examined associations between risk factors present at Wave 1 and suicide attempts at Wave 2 (n=169) among individuals with major depressive disorder at baseline assessment (n=6004). Risk factors for incident suicide attempts at Wave 2 (n=63) were identified among those with major depressive disorder at Wave 1 and no lifetime history of suicide attempts (n=5170). Results revealed specific comorbid anxiety, personality, and substance use disorders to be associated with incident suicide attempts at Wave 2. Comorbid borderline personality disorder was strongly associated with suicide attempts in all models. Several comorbid disorders were strongly associated with suicide attempts at Wave 2 even after adjusting for previous suicidal behavior, notably posttraumatic stress disorder (adjusted odds ratio (AOR)=2.20; 95% confidence interval (95% CI) 1.27-3.83) and dependent personality disorder (AOR=4.43; 95% CI 1.93-10.18). These findings suggest that mental illness comorbidity confers an increased risk of future suicide attempts in major depressive disorder that is not solely accounted for by past suicidal behavior.

  1. Emotional development in children with tics : a longitudinal population-based study

    NARCIS (Netherlands)

    Hoekstra, P. J.; Lundervold, A. J.; Lie, S. A.; Gillberg, C.; Plessen, Kerstin J.

    2013-01-01

    Children with tics often experience accompanying problems that may have more impact on their well being and quality of life than the tics themselves. The present study investigates characteristics and the course of associated problems. In a population-based follow-up study, we investigated the devel

  2. Longitudinal Detection and Persistence of Minority Drug-Resistant Populations and Their Effect on Salvage Therapy.

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    Masako Nishizawa

    Full Text Available Drug-resistant HIV are more prevalent and persist longer than previously demonstrated by bulk sequencing due to the ability to detect low-frequency variants. To clarify a clinical benefit to monitoring minority-level drug resistance populations as a guide to select active drugs for salvage therapy, we retrospectively analyzed the dynamics of low-frequency drug-resistant population in antiretroviral (ARV-exposed drug resistant individuals.Six HIV-infected individuals treated with ARV for more than five years were analyzed. These individuals had difficulty in controlling viremia, and treatment regimens were switched multiple times guided by standard drug resistance testing using bulk sequencing. To detect minority variant populations with drug resistance, we used a highly sensitive allele-specific PCR (AS-PCR with detection thresholds of 0.3-2%. According to ARV used in these individuals, we focused on the following seven reverse transcriptase inhibitor-resistant mutations: M41L, K65R, K70R, K103N, Y181C, M184V, and T215F/Y. Results of AS-PCR were compared with bulk sequencing data for concordance and presence of additional mutations. To clarify the genetic relationship between low-frequency and high-frequency populations, AS-PCR amplicon sequences were compared with bulk sequences in phylogenetic analysis.The use of AS-PCR enabled detection of the drug-resistant mutations, M41L, K103N, Y181C, M184V and T215Y, present as low-frequency populations in five of the six individuals. These drug resistant variants persisted for several years without ARV pressure. Phylogenetic analysis indicated that pre-existing K103N and T215I variants had close genetic relationships with high-frequency K103N and T215I observed during treatment.Our results demonstrate the long-term persistence of drug-resistant viruses in the absence of drug pressure. The rapid virologic failures with pre-existing mutant viruses detectable by AS-PCR highlight the clinical importance of

  3. Factors influencing exclusive breastfeeding among Iranian mothers: A longitudinal population-based study

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    Saffari, Mohsen; Pakpour, Amir H.; Chen, Hui

    2017-01-01

    Background: Exclusive breastfeeding (EBF) contributes to the health and survival of the newborns. Many factors influence the EBF behavior. This study aimed to identify the determinant factors in order to improve the practice of EBF among Iranian mothers. Methods: A longitudinal study was carried out in 1445 mothers with newborns in Qazvin city, Iran (September 2015-March 2016). Demographic variables as well as the constructs of theory of planned behavior (TBP) were measured by questionnaires. Bivariate analysis using Pearson and Spearman correlation tests with analysis of variance were used to investigate the associations among the variables. Both hierarchal multiple regression and logistic regression were applied to identify potential determinative factors for the EBF. Results: Nearly, 80% (CI: 77.97-82.63%) of the participants had the intention of EBF. All TPB constructs, moral norms, and self-identity were significantly correlated with each other (r: 0.09- 0.40, P < 0.01). Some demographic variables such as age, income, employment and primiparity were also correlated with the EBF (r: 0.11-0.15, P < 0.05). The constructs of the TPB were able to predict the EBF behavior, which account for 49% of the variance in the predicting factors (df = 8, F = 7.70). The self-identity and moral norms accounted for an additional 15% of the variance (df = 10, F = 3.16). Younger mothers with lower socio-economic status were at higher risk of EBF cessation. The intention has a greater impact on the initiation of EBF than perceived behavioral control (PBC) but not for the maintenance of EBF (OR, 2.88 [CI: 2.38-3.48] & 1.13 [CI:1.03- 1.23] vs. OR, 1.27 [CI:1.15-1.39] & 2.66 [CI: 2.02-3.49]). Conclusion: The interventions to promote knowledge, attitude and behavioral control towards the EBF should be considered especially in the young mothers with low socio-economic status. PMID:28058240

  4. Factors influencing exclusive breastfeeding among Iranian mothers: A longitudinal population-based study.

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    Saffari, Mohsen; Pakpour, Amir H; Chen, Hui

    2017-01-01

    Background: Exclusive breastfeeding (EBF) contributes to the health and survival of the newborns. Many factors influence the EBF behavior. This study aimed to identify the determinant factors in order to improve the practice of EBF among Iranian mothers. Methods: A longitudinal study was carried out in 1445 mothers with newborns in Qazvin city, Iran (September 2015-March 2016). Demographic variables as well as the constructs of theory of planned behavior (TBP) were measured by questionnaires. Bivariate analysis using Pearson and Spearman correlation tests with analysis of variance were used to investigate the associations among the variables. Both hierarchal multiple regression and logistic regression were applied to identify potential determinative factors for the EBF. Results: Nearly, 80% (CI: 77.97-82.63%) of the participants had the intention of EBF. All TPB constructs, moral norms, and self-identity were significantly correlated with each other (r: 0.09- 0.40, P < 0.01). Some demographic variables such as age, income, employment and primiparity were also correlated with the EBF (r: 0.11-0.15, P < 0.05). The constructs of the TPB were able to predict the EBF behavior, which account for 49% of the variance in the predicting factors (df = 8, F = 7.70). The self-identity and moral norms accounted for an additional 15% of the variance (df = 10, F = 3.16). Younger mothers with lower socio-economic status were at higher risk of EBF cessation. The intention has a greater impact on the initiation of EBF than perceived behavioral control (PBC) but not for the maintenance of EBF (OR, 2.88 [CI: 2.38-3.48] & 1.13 [CI:1.03- 1.23] vs. OR, 1.27 [CI:1.15-1.39] & 2.66 [CI: 2.02-3.49]). Conclusion: The interventions to promote knowledge, attitude and behavioral control towards the EBF should be considered especially in the young mothers with low socio-economic status.

  5. Emotional development in children with tics: a longitudinal population-based study.

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    Hoekstra, P J; Lundervold, A J; Lie, S A; Gillberg, C; Plessen, Kerstin J

    2013-03-01

    Children with tics often experience accompanying problems that may have more impact on their well being and quality of life than the tics themselves. The present study investigates characteristics and the course of associated problems. In a population-based follow-up study, we investigated the developmental trajectory of children with and without tics when they were 7-9 years old. Parents and teachers completed the strengths and difficulties questionnaire (SDQ) when the children were 7-9 years (wave 1) and 4 years later (wave 2). Using strict criteria, we identified 38 children with tics in the cohort of 4,025 children (0.94% of the total cohort) with a preponderance of boys (78.9%). 22 children (57.9%) in the group with tics had only motor tics, and 16 (42.1%) had both motor and vocal tics. Children with tics had significantly higher parent- and teacher-rated SDQ total difficulty scores and subscale scores in both waves. Children with tics experienced an increase in emotional problems and in peer problems between the first and the second wave. This study in a general population indicates that the presence of tics is associated with a range of internalizing and externalizing difficulties, as well as problems in peer relationships. Moreover, our study indicates that emotional and peer problems tend to increase over time in the group of children with tics.

  6. Parents bereaved by offspring suicide: a population-based longitudinal case-control study.

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    Bolton, James M; Au, Wendy; Leslie, William D; Martens, Patricia J; Enns, Murray W; Roos, Leslie L; Katz, Laurence Y; Wilcox, Holly C; Erlangsen, Annette; Chateau, Dan; Walld, Randy; Spiwak, Rae; Seguin, Monique; Shear, Katherine; Sareen, Jitender

    2013-02-01

    CONTEXT Suicide bereavement remains understudied and poorly understood. OBJECTIVES To examine outcomes of parents bereaved by the suicide death of their offspring and to compare these with both nonbereaved parent controls and parents who had offspring die in a motor vehicle crash (MVC). DESIGN Population-based case-control study. Suicide-bereaved parents were compared with nonbereaved matched control parents in the general population (n = 1415) and with MVC-bereaved parents (n = 1132) on the rates of physician-diagnosed mental and physical disorders, social factors, and treatment use in the 2 years after death of the offspring. Adjusted relative rates (ARRs) were generated by generalized estimating equation models and adjusted for confounding factors. SETTING Manitoba, Canada. PARTICIPANTS All identifiable parents who had an offspring die by suicide between 1996 and 2007 (n = 1415). MAIN OUTCOME MEASURES Mental and physical disorders, social factors, and treatment use. RESULTS Suicide bereavement was associated with an increased rate of depression (ARR, 2.14; 95% CI, 1.88-2.43), anxiety disorders (ARR, 1.41; 95% CI, 1.24-1.60), and marital breakup (ARR, 1.18; 95% CI, 1.13-1.23) in the 2 years after the suicide of an offspring, as compared with the 2 years prior to the death. Suicide-bereaved and MVC-bereaved parents had very few differences on predeath to postdeath outcomes. Depression rate increases were greater for MVC-bereaved parents (19.9%) compared with suicide-bereaved parents (15.9%; P = .005), whereas suicide-bereaved parents had higher rate increases of hospitalization for mental illness (P = .049). Suicide-bereaved parents were more likely than their MVC-bereaved counterparts to have depression (ARR, 1.30; 95% CI, 1.06-1.61), physical disorders (ARR, 1.32; 95% CI, 1.19-1.45), and low income (ARR, 1.34; 95% CI, 1.18-1.51) before their offspring's death. CONCLUSIONS Suicide bereavement is associated with adverse mental health and social outcomes

  7. Incidence and predictors of multimorbidity in the elderly: a population-based longitudinal study.

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    René Melis

    Full Text Available We aimed to calculate 3-year incidence of multimorbidity, defined as the development of two or more chronic diseases in a population of older people free from multimorbidity at baseline. Secondly, we aimed to identify predictors of incident multimorbidity amongst life-style related indicators, medical conditions and biomarkers.Data were gathered from 418 participants in the first follow up of the Kungsholmen Project (Stockholm, Sweden, 1991-1993, 78+ years old who were not affected by multimorbidity (149 had none disease and 269 one disease, including a social interview, a neuropsychological battery and a medical examination.After 3 years, 33.6% of participants who were without disease and 66.4% of those with one disease at baseline, developed multimorbidity: the incidence rate was 12.6 per 100 person-years (95% CI: 9.2-16.7 and 32.9 per 100 person-years (95% CI: 28.1-38.3, respectively. After adjustments, worse cognitive function (OR, 95% CI, for 1 point lower Mini-Mental State Examination: 1.22, 1.00-1.48 was associated with increased risk of multimorbidity among subjects with no disease at baseline. Higher age was the only predictor of multimorbidity in persons with one disease at baseline.Multimorbidity has a high incidence at old age. Mental health-related symptoms are likely predictors of multimorbidity, suggesting a strong impact of mental disorders on the health of older people.

  8. Under the skin: using theories from biology and the social sciences to explore the mechanisms behind the black-white health gap.

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    Green, Tiffany L; Darity, William A

    2010-04-01

    Equity and social well-being considerations make Black-White health disparities an area of important concern. Although previous research suggests that discrimination- and poverty-related stressors play a role in African American health outcomes, the mechanisms are unclear. Allostatic load is a concept that can be employed to demonstrate how environmental stressors, including psychosocial ones, may lead to a cumulative physiological toll on the body. We discuss both the usefulness of this framework for understanding how discrimination can lead to worse health among African Americans, and the challenges for conceptualizing biological risk with existing data and methods. We also contrast allostatic load with theories of historical trauma such as posttraumatic slavery syndrome. Finally, we offer our suggestions for future interdisciplinary research on health disparities.

  9. The Association Between Peptic Ulcer Disease and Ischemic Stroke: A Population-Based Longitudinal Study.

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    Cheng, Tain-Junn; Guo, How-Ran; Chang, Chia-Yu; Weng, Shih-Feng; Li, Pi-I; Wang, Jhi-Joung; Wu, Wen-Shiann

    2016-05-01

    Stroke is a common cause of death worldwide, but about 30% of ischemic stroke (IS) patients have no identifiable contributing risk factors. Because peptic ulcer disease (PUD) and vascular events share some common risk factors, we conducted a population-based study to evaluate the association between PUD and IS.We followed up a representative sample of 1 million residents of Taiwan using the National Health Insurance Research Database from 1997 to 2011. We defined patients who received medications for PUD and had related diagnosis codes as the PUD group, and a reference group matched by age and sex was sampled from those who did not have PUD. We also collected data on medical history and monthly income. The events of IS occurred after enrollment were compared between the 2 groups. The data were analyzed using Cox proportional hazard models at the 2-tailed significant level of 0.05.The PUD group had higher income and prevalence of hypertension, diabetes mellitus (DM), heart disease, and hyperlipidemia. They also had a higher risk of developing IS with an adjusted hazard ratio of 1.31 (95% confidence interval: 1.20-1.41). Other independent risk factors included male sex, older age, lower income, and co-morbidity of hypertension, diabetes mellitus (DM), and heart disease.PUD is a risk factor for IS, independent of conventional risk factors such as male sex, older age, lower income, and co-morbidity of hypertension, DM, and heart disease. Prevention strategies taking into account PUD should be developed and evaluated.

  10. Prenatal stress and gender role behavior in girls and boys: a longitudinal, population study.

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    Hines, Melissa; Johnston, Katie J; Golombok, Susan; Rust, John; Stevens, Madeleine; Golding, Jean

    2002-09-01

    Prenatal stress influences neural and behavioral sexual differentiation in rodents. Male offspring of stressed pregnancies show reduced masculine-typical characteristics and increased feminine-typical characteristics, whereas female offspring show the opposite pattern, reduced feminine-typical and increased masculine-typical characteristics. These outcomes resemble those seen following manipulations of gonadal hormones and are thought to occur because stress influences these hormones during critical periods of development. Research on prenatal stress and human sexual differentiation has produced inconsistent results, perhaps because studies have used small samples and assessed prenatal stress retrospectively. We related maternal self-reports of prenatal stress to childhood gender role behavior in a prospective, population study of 13,998 pregnancies resulting in 14,138 offspring. Neither stress reported during the first 18 weeks of pregnancy nor stress reported from week 19 of pregnancy to week 8 postnatal related to gender role behavior in male offspring at the age of 42 months. In female offspring, maternal reports of stress during both periods showed only small correlations with masculine-typical behavior. Although this relationship remained significant when other factors that related to stress were controlled, these other factors made larger contributions to girls' gender role behavior than did prenatal stress. In addition, in both boys and girls, older male or female siblings, parental adherence to traditional sex roles, maternal use of tobacco or alcohol during pregnancy, and maternal education all related significantly to gender role behavior. Our results suggest that prenatal stress does not influence the development of gender role behavior in boys and appears to have relatively little, if any, influence on gender role behavior in girls.

  11. Childhood ADHD and risk for substance dependence in adulthood: a longitudinal, population-based study.

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    Sharon Levy

    Full Text Available Adolescents with attention-deficit/hyperactivity disorder (ADHD are known to be at significantly greater risk for the development of substance use disorders (SUD compared to peers. Impulsivity, which could lead to higher levels of drug use, is a known symptom of ADHD and likely accounts, in part, for this relationship. Other factors, such as a biologically increased susceptibility to substance dependence (addiction, may also play a role.This report further examines the relationships between childhood ADHD, adolescent- onset SUD, and substance abuse and substance dependence in adulthood.Individuals with childhood ADHD and non-ADHD controls from the same population-based birth cohort were invited to participate in a prospective outcome study. Participants completed a structured neuropsychiatric interview with modules for SUD and a psychosocial questionnaire. Information on adolescent SUD was obtained retrospectively, in a previous study, from medical and school records. Associations were summarized using odds ratios (OR and 95% CIs estimated from logistic regression models adjusted for age and gender.A total of 232 ADHD cases and 335 non-ADHD controls participated (mean age, 27.0 and 28.6 years, respectively. ADHD cases were more likely than controls to have a SUD diagnosed in adolescence and were more likely to have alcohol (adjusted OR 14.38, 95% CI 1.49-138.88 and drug (adjusted OR 3.48, 95% CI 1.38-8.79 dependence in adulthood. The subgroup of participating ADHD cases who did not have SUD during adolescence were no more likely than controls to develop new onset alcohol dependence as adults, although they were significantly more likely to develop new onset drug dependence.Our study found preliminary evidence that adults with childhood ADHD are more susceptible than peers to developing drug dependence, a disorder associated with neurological changes in the brain. The relationship between ADHD and alcohol dependence appears to be more complex.

  12. Mental illness related disparities in diabetes prevalence, quality of care and outcomes: a population-based longitudinal study

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    Emery Jonathan D

    2011-11-01

    Full Text Available Abstract Background Health care disparity is a public health challenge. We compared the prevalence of diabetes, quality of care and outcomes between mental health clients (MHCs and non-MHCs. Methods This was a population-based longitudinal study of 139,208 MHCs and 294,180 matched non-MHCs in Western Australia (WA from 1990 to 2006, using linked data of mental health registry, electoral roll registrations, hospital admissions, emergency department attendances, deaths, and Medicare and pharmaceutical benefits claims. Diabetes was identified from hospital diagnoses, prescriptions and diabetes-specific primary care claims (17,045 MHCs, 26,626 non-MHCs. Both univariate and multivariate analyses adjusted for socio-demographic factors and case mix were performed to compare the outcome measures among MHCs, category of mental disorders and non-MHCs. Results The prevalence of diabetes was significantly higher in MHCs than in non-MHCs (crude age-sex-standardised point-prevalence of diabetes on 30 June 2006 in those aged ≥20 years, 9.3% vs 6.1%, respectively, P 1c, microalbuminuria, blood lipids was suboptimal in both groups, but was lower in MHCs (for all tests combined; adjusted OR 0.81, 95% CI 0.78 to 0.85, at one year; and adjusted rate ratio (RR 0.86, 95% CI 0.84 to 0.88, during the study period. MHCs also had increased risks of hospitalisation for diabetes complications (adjusted RR 1.20, 95% CI 1.17 to 1.24, diabetes-related mortality (1.43, 1.35 to 1.52 and all-cause mortality (1.47, 1.42 to 1.53. The disparities were most marked for alcohol/drug disorders, schizophrenia, affective disorders, other psychoses and personality disorders. Conclusions MHCs warrant special attention for primary and secondary prevention of diabetes, especially at the primary care level.

  13. Antiretroviral therapy availability and HIV disclosure to spouse in Rakai, Uganda: a longitudinal population-based study

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    HABERLEN, Sabina A.; NAKIGOZI, Gertrude; GRAY, Ronald H.; BRAHMBHATT, Heena; SSEKASANVU, Joseph; SERWADDA, David; NALUGODA, Fred; KAGAAYI, Joseph; WAWER, Maria. J.

    2015-01-01

    Background A decade after the rollout of antiretroviral therapy (ART) in sub-Saharan Africa, the effects of this structural change on social aspects of HIV such as rates of HIV disclosure to partners remain largely unmeasured. We evaluated whether the introduction of ART was associated with disclosure of HIV diagnosis to spouses in Rakai, Uganda, using longitudinal, population-based data. Methods We identified individuals in marital/cohabitating unions who were newly diagnosed with HIV in Rakai Community Cohort Study (RCCS) surveys between 2000 and 2008, where antiretroviral therapy (ART) was introduced in mid-2004. Using discrete-time survival analysis, we assessed the hazard of self-reported HIV disclosure to spouse after diagnosis pre- and post-ART rollout, adjusting for individual and union characteristics. Disclosure in the ART period was further stratified by ART initiation. Results The analysis included 557 married adults, 264 of whom were diagnosed with HIV before ART was available (2000-2004) and 293 diagnosed after ART was introduced (2005-2008). The cumulative incidence of self-reported disclosure was 75.2% in the post-ART period, compared to 58.3% before ART availability (p<0.001, adjusted hazard 1.46 [95% CI 1.16, 1.83]). In the post-ART period, observed disclosure rates were 39% (72/184) among those not in HIV care, 65% (82/126) among those in pre-ART care, and 85% (64/75) among persons on ART (p<0.001). Conclusions Treatment availability and use, especially ART initiation, was associated with increased self-disclosure of HIV diagnosis to partners. ART access may facilitate the prevention of transmission to uninfected partners and linkage to treatment for infected couples. PMID:26009833

  14. Increased risk of ischemic stroke in young patients with ankylosing spondylitis: a population-based longitudinal follow-up study.

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    Chia-Wei Lin

    Full Text Available BACKGROUND: Prospective data on the association between ischemic stroke and ankylosing spondylitis (AS in the young are sparse. The purpose of this population-based, age- and sex-matched longitudinal follow-up study was to investigate the risk of developing ischemic stroke in young patients with AS. METHODS: A total of 4562 patients aged 18- to 45-year-old with at least two ambulatory visits in 2001 with a principal diagnosis of AS were enrolled in the AS group. The non-AS group consisted of 22810 age- and sex-matched, randomly sampled subjects without AS. The two-year ischemic stroke-free survival rate for each group were calculated using the Kaplan-Meier method. Cox proportional hazards regression analysis was used to estimate the hazard ratio of ischemic stroke after adjusting for demographic and clinical covariates. RESULTS: During follow-up, 21 patients in the AS group and 53 in the non-AS group developed ischemic stroke. The ischemic stroke-free survival rate over the 2 year follow-up was lower in the AS group than the non-AS group (p = 0.0021. The crude hazard ratio of ischemic stroke for the AS group was 1.98 (95% CI, 1.20-3.29; p = 0.0079 and the adjusted hazard ratio after controlling for demographic and comorbid medical disorders was 1.93 (95% CI, 1.16-3.20; p = 0.0110. CONCLUSION: Our study showed an increased risk of developing ischemic stroke in young patients with AS.

  15. A longitudinal cohort based association study between uric acid level and metabolic syndrome in Chinese Han urban male population

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    Zhang Qian

    2012-06-01

    Full Text Available Abstract Background It has been recently demonstrated that serum uric acid (UA is associated with metabolic syndrome (MetS or its related clinical indications based on cross-sectional or prospective cohort studies. Nonetheless, due to the fact that UA level constantly fluctuates from time to time even for the person, using a single measure of UA level at baseline of those studies may not be sufficient for estimating the UA-Mets association. Methods To further estimate this time-dependent association, we fitted a generalized estimating equation (GEE regression model with data from a large-scale 6-year longitudinal study, which included 2222 participants aged > =25 years with an average of 3.5 repeated measures of UA per person in the Health Management Center of Shandong Provincial Hospital, Shandong, China. Results After adjusting for other potential confounding factors (i.e., total cholesterol, low-density lipoprotein, it was verified that time-dependent UA level was an independent risk factor for MetS (OR = 1.6920, p  Conclusions Serum UA level may serve as an important risk factor of MetS. Additionally, our study suggested that UA level be an independent risk factor to obesity, hypertension and dyslipidemia, but a protective factor to hyperglycemia. These findings are concordant with results from other studies on Asian populations, and jointly provide a basis to further develop a risk assessment model for predicting MetS using UA levels and other factors in China.

  16. A study of longitudinal data examining concomitance of pain and cognition in an elderly long-term care population

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    Burfield AH

    2012-03-01

    Full Text Available Allison H Burfield1, Thomas TH Wan2, Mary Lou Sole3, James W Cooper41Gerontology Program, School of Nursing, College of Health and Human Services, University of North Carolina, Charlotte, NC, USA; 2Health Services, Administration, and Medical Education, Director, Doctoral Program in Public Affairs, Associate Dean for Research, College of Health and Public Affairs, 3College of Nursing, University of Central Florida, Orlando, FL, USA; 4College of Pharmacy, University of Georgia, Athens, GA, USAPurpose: To examine if a concomitant relationship exists between cognition and pain in an elderly population residing in long-term care.Background/significance: Prior research has found that cognitive load mediates interpretation of a stimulus. In the presence of decreased cognitive capacity as with dementia, the relationship between cognition and increasing pain is unknown in the elderly.Patients and methods: Longitudinal cohort design. Data collected from the Minimum Data Set-Resident Assessment Instrument (MDS-RAI from the 2001–2003 annual assessments of nursing home residents. A covariance model was used to evaluate the relationship between cognition and pain at three intervals.Results: The sample included 56,494 subjects from nursing homes across the United States, with an average age of 83 ± 8.2 years. Analysis of variance scores (ANOVAs indicated a significant effect (P < 0.01 for pain and cognition, with protected t test revealing scores decreasing significantly with these two measures. Relative stability was found for pain and cognition over time. Greater stability was found in the cognitive measure than the pain measure. Cross-legged effects observed between cognition and pain measures were inconsistent. A concomitant relationship was not found between cognition and pain. Even though the relationship was significant at the 0.01 level, the correlations were low (r ≤ 0.08, indicating a weak association between cognition and pain

  17. Determinants and Regression Equations for the Calculation of z Scores of Left Ventricular Tissue Doppler Longitudinal Indexes in a Healthy Italian Pediatric Population

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    Veronica Fibbi

    2015-01-01

    Full Text Available Aim. We investigated the predictors of tissue Doppler left ventricular (LV longitudinal indexes in a healthy Italian pediatric population and established normative data and regression equations for the calculation of z scores. Methods and Results. A total of 369 healthy subjects aged 1–17 years (age of 6.4 ± 1.1 years, 49.1% female underwent echocardiography. LV peak longitudinal velocity at systole (s', early diastole (e', and late diastole (a' was determined by tissue Doppler. The ratio of peak early diastolic LV filling velocity to e' was calculated. Age was the only independent determinant of s' (β=0.491, p<0.0001 and the strongest determinant of e' (β=0.334, p<0.0001 and E/e' (β=-0.369, p<0.0001. Heart rate was the main determinant of a' (β=0.265, p<0.0001. Male gender showed no effects except for a weak association with lateral s', suggesting no need of gender-specific reference ranges. Age-specific reference ranges, regression equations, and scatterplots for the calculation of z scores were determined for each index. Conclusion. In a pediatric Italian population, age was the strongest determinant of LV longitudinal dynamics. The availability of age-specific normality data for the calculation of z scores may allow for correctly detecting LV dysfunction in pediatric pathological populations.

  18. Food and fitness: associations between crop yields and life-history traits in a longitudinally monitored pre-industrial human population.

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    Hayward, Adam D; Holopainen, Jari; Pettay, Jenni E; Lummaa, Virpi

    2012-10-22

    Severe food shortage is associated with increased mortality and reduced reproductive success in contemporary and historical human populations. Studies of wild animal populations have shown that subtle variation in environmental conditions can influence patterns of mortality, fecundity and natural selection, but the fitness implications of such subtle variation on human populations are unclear. Here, we use longitudinal data on local grain production, births, marriages and mortality so as to assess the impact of crop yield variation on individual age-specific mortality and fecundity in two pre-industrial Finnish populations. Although crop yields and fitness traits showed profound year-to-year variation across the 70-year study period, associations between crop yields and mortality or fecundity were generally weak. However, post-reproductive individuals of both sexes, and individuals of lower socio-economic status experienced higher mortality when crop yields were low. This is the first longitudinal, individual-based study of the associations between environmental variation and fitness traits in pre-industrial humans, which emphasizes the importance of a portfolio of mechanisms for coping with low food availability in such populations. The results are consistent with evolutionary ecological predictions that natural selection for resilience to food shortage is likely to weaken with age and be most severe on those with the fewest resources.

  19. Individual and Neighborhood Socioeconomic Status and Healthcare Resources in Relation to Black-White Breast Cancer Survival Disparities

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    Tomi F. Akinyemiju

    2013-01-01

    Full Text Available Background. Breast cancer survival has improved significantly in the US in the past 10–15 years. However, disparities exist in breast cancer survival between black and white women. Purpose. To investigate the effect of county healthcare resources and SES as well as individual SES status on breast cancer survival disparities between black and white women. Methods. Data from 1,796 breast cancer cases were obtained from the Surveillance Epidemiology and End Results and the National Longitudinal Mortality Study dataset. Cox Proportional Hazards models were constructed accounting for clustering within counties. Three sequential Cox models were fit for each outcome including demographic variables; demographic and clinical variables; and finally demographic, clinical, and county-level variables. Results. In unadjusted analysis, black women had a 53% higher likelihood of dying of breast cancer and 32% higher likelihood of dying of any cause (P<0.05 compared with white women. Adjusting for demographic variables explained away the effect of race on breast cancer survival (HR, 1.40; 95% CI, 0.99–1.97, but not on all-cause mortality. The racial difference in all-cause survival disappeared only after adjusting for county-level variables (HR, 1.27; CI, 0.95–1.71. Conclusions. Improving equitable access to healthcare for all women in the US may help eliminate survival disparities between racial and socioeconomic groups.

  20. Visual Impairment, Hearing Loss and Cognitive Function in an Older Population: Longitudinal Findings from the Blue Mountains Eye Study.

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    Thomas Hong

    Full Text Available The presence of visual impairment (VI and hearing loss (HL with may be a marker for subsequent cognitive decline over time in older people. A prospective, longitudinal population-based study of the 3654 participants of the Blue Mountains Eye Study were assessed for the associations between VI and HL and a decline in mini-mental state examination (MMSE scores over a duration of 10 years from the 5-year (baseline of this report to the 15-year follow-up visits. MMSE was assessed at the 5-, 10- and 15-year follow-up visits. A decline ≥3 scores from 5-year to 10- or 15-year visits indicated possible cognitive decline. VI was defined as best-corrected visual acuity 40 decibels in the worse-ear and dual sensory impairment (DSI was defined by the co-presence of VI and HL, detected at 5-year follow-up (baseline of this report. Participants with no VI and HL over the same 5- or 10-year corresponding period were controls. Associations of VI, HL and DSI with possible cognitive decline were assessed using logistic regression models adjusting for age and sex after excluding subjects with a stroke history. The presence of VI, HL or DSI was not associated with possible cognitive decline over 5 years (odds ratio (OR 0.84, 95% confidence-intervals (CI 0.40-1.79, OR 1.02, 95% CI 0.61-1.70 and 1.41, 95% CI 0.54-3.72, respectively or 10 years (OR 1.09, 95% CI 0.52-2.30, OR 1.09, 95% CI 0.65-1.82 and 1.15, 95% CI 0.28-4.73, respectively. There were no changes to these findings after adjustment for other potential confounders. Age was significantly associated with possible cognitive decline (OR 1.07, 95% CI 1.04-1.10 for both periods. Neither visual impairment, hearing loss nor dual sensory impairment was independently associated with subsequent decline in cognition.

  1. Is Gender More Important and Meaningful Than Race? An Analysis of Racial and Gender Identity Among Black, White, and Mixed-Race Children.

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    Rogers, Leoandra Onnie; Meltzoff, Andrew N

    2016-10-13

    Objectives: Social categories shape children's lives in subtle and powerful ways. Although research has assessed children's knowledge of social groups, most prominently race and gender, few studies have examined children's understanding of their own multiple social identities and how they intersect. This paper explores how children evaluate the importance and meaning of their racial and gender identities, and variation in these evaluations based on the child's own age, gender, and race. Method: Participants were 222 Black, White, and Mixed-Race children (girls: n = 136; Mage = 9.94 years). Data were gathered in schools via 1-on-1 semistructured interviews. Analyses focused on specific measures of the importance and meaning of racial and gender identity for children. Results: We found that: (a) children rate gender as a more important identity than race; (b) the meanings children ascribe to gender identity emphasized inequality and group difference whereas the meaning of race emphasized physical appearance and humanism/equality; and (c) children's assessments of importance and meaning varied as a function of child race and gender, but not age. Conclusion: The findings extend research on young children's social identity development and the role of culture and context in children's emerging racial and gender identities. Implications for identity theory and development and intergroup relations are discussed. (PsycINFO Database Record

  2. Associations between safety from crime, cycling, and obesity in a Dutch elderly population: results from the longitudinal aging study Amsterdam

    NARCIS (Netherlands)

    Kremers, S.P.J.; de Bruijn, G.J.; Visscher, T.L.S.; Deeg, D.J.H.; Thomése, G.C.F.; Visser, M.; van Mechelen, W.; Brug, J.

    2012-01-01

    The objective of this cross-sectional study was to investigate differences in associations between crime rates, cycling, and weight status between people living in low and high socioeconomic status (SES) neighbourhoods. In total, 470 participants in the Longitudinal Aging Study Amsterdam were includ

  3. Black-White Differences in Child Maltreatment Reports and Foster Care Placements: A Statistical Decomposition Using Linked Administrative Data.

    Science.gov (United States)

    Maloney, Tim; Jiang, Nan; Putnam-Hornstein, Emily; Dalton, Erin; Vaithianathan, Rhema

    2017-03-01

    Introduction Official statistics have confirmed that relative to their presence in the population and relative to white children, black children have consistently higher rates of contact with child protective services (CPS). We used linked administrative data and statistical decomposition techniques to generate new insights into black and white differences in child maltreatment reports and foster care placements. Methods Birth records for all children born in Allegheny County, Pennsylvania, between 2008 and 2010 were linked to administrative service records originating in multiple county data systems. Differences in rates of involvement with child protective services between black and white children by age 4 were decomposed using nonlinear regression techniques. Results Black children had rates of CPS involvement that were 3 times higher than white children. Racial differences were explained solely by parental marital status (i.e., being unmarried) and age at birth (i.e., predominantly teenage mothers). Adding other covariates did not capture any further racial differences in maltreatment reporting or foster care placement rates, they simply shifted differences already explained by marital status and age to these other variables. Discussion Racial differences in rates of maltreatment reports and foster care placements can be explained by a basic model that adjusts only for parental marital status and age at the time of birth. Increasing access to early prevention services for vulnerable families may reduce disparities in child protective service involvement. Using birth records linked to other administrative data sources provides an important means to developing population-based research.

  4. Rate of change in adiposity and its relationship to concomitant changes in cardiovascular risk variables among biracial (black-white) children and young adults: The Bogalusa Heart Study.

    Science.gov (United States)

    Srinivasan, S R; Myers, L; Berenson, G S

    2001-03-01

    To assess the annual rate of change in adiposity and its relationship to concomitant changes in cardiovascular risk variables during childhood and young adulthood, serial data on black and white children (n = 3,459; initial and follow-up mean age, 8.1 and 14.4 years) and young adults (n = 1,263; initial and follow-up mean age, 22.5 and 30.9 years) enrolled in the Bogalusa Heart Study were examined. Body mass index (BMI) and sum of subscapular and triceps skinfolds were used as indicators of adiposity. In addition, measurements were made of systolic and diastolic blood pressure and fasting levels of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, insulin, and glucose. Annualized rate of change for each variable was estimated. The rate of increase in adiposity was significantly more pronounced during childhood versus adulthood. Race difference (blacks > whites) in the rate of increase in adiposity was seen only among females. Females, black females in particular, displayed greater rate of increase in adiposity than males. In a multivariate analysis, the rate of increase in adiposity was related independently of baseline age and baseline adiposity to adverse changes in measured cardiovascular risk variables, except glucose. Many of these associations were modulated significantly by race, sex, and age group. The impact was relatively greater for blood pressure and LDL cholesterol in adults and for triglycerides in children. The changes in blood pressure, LDL cholesterol, and HDL cholesterol were greater in whites, while the rate of increase in insulin was greater in blacks. Females displayed greater changes in blood pressure, HDL cholesterol, and insulin. On the other hand, the rate of increase in triglycerides was greater in males. These results indicate that increases in adiposity regardless of initial status of body fatness alter cardiovascular risk variables towards increased risk beginning in childhood, and

  5. Maternal depressive symptoms across early childhood and asthma in school children: findings from a Longitudinal Australian Population Based Study.

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    Rebecca Giallo

    Full Text Available There is a growing body of evidence attesting to links between early life exposure to stress and childhood asthma. However, available evidence is largely based on small, genetically high risk samples. The aim of this study was to explore the associations between the course of maternal depressive symptoms across early childhood and childhood asthma in a nationally representative longitudinal cohort study of Australian children. Participants were 4164 children and their biological mothers from the Longitudinal Study of Australian Children. Latent class analysis identified three trajectories of maternal depressive symptoms across four biennial waves from the first postnatal year to when children were 6-7 years: minimal symptoms (74.6%, sub-clinical symptoms (20.8%, and persistent and increasing high symptoms (4.6%. Logistic regression analyses revealed that childhood asthma at age 6-7 years was associated with persistent and increasing high depressive symptoms after accounting for known risk factors including smoking during pregnancy and maternal history of asthma (adjusted OR 2.36, 95% CI 1.61-3.45, p.001. Our findings from a nationally representative sample of Australian children provide empirical support for a relationship between maternal depressive symptoms across the early childhood period and childhood asthma. The burden of disease from childhood asthma may be reduced by strengthening efforts to promote maternal mental health in the early years of parenting.

  6. Maternal depressive symptoms across early childhood and asthma in school children: findings from a Longitudinal Australian Population Based Study.

    Science.gov (United States)

    Giallo, Rebecca; Bahreinian, Salma; Brown, Stephanie; Cooklin, Amanda; Kingston, Dawn; Kozyrskyj, Anita

    2015-01-01

    There is a growing body of evidence attesting to links between early life exposure to stress and childhood asthma. However, available evidence is largely based on small, genetically high risk samples. The aim of this study was to explore the associations between the course of maternal depressive symptoms across early childhood and childhood asthma in a nationally representative longitudinal cohort study of Australian children. Participants were 4164 children and their biological mothers from the Longitudinal Study of Australian Children. Latent class analysis identified three trajectories of maternal depressive symptoms across four biennial waves from the first postnatal year to when children were 6-7 years: minimal symptoms (74.6%), sub-clinical symptoms (20.8%), and persistent and increasing high symptoms (4.6%). Logistic regression analyses revealed that childhood asthma at age 6-7 years was associated with persistent and increasing high depressive symptoms after accounting for known risk factors including smoking during pregnancy and maternal history of asthma (adjusted OR 2.36, 95% CI 1.61-3.45), p.001). Our findings from a nationally representative sample of Australian children provide empirical support for a relationship between maternal depressive symptoms across the early childhood period and childhood asthma. The burden of disease from childhood asthma may be reduced by strengthening efforts to promote maternal mental health in the early years of parenting.

  7. Who is maintaining weight in a middle-aged population in Sweden? A longitudinal analysis over 10 years

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    Wall Stig

    2007-06-01

    Full Text Available Abstract Background Obesity has primarily been addressed with interventions to promote weight loss and these have been largely unsuccessful. Primary prevention of obesity through support of weight maintenance may be a preferable strategy although to date this has not been the main focus of public health interventions. The aim of this study is to characterize who is not gaining weight during a 10 year period in Sweden. Methods Cross-sectional and longitudinal studies were conducted in adults aged 30, 40, 50 and 60 years during the Västerbotten Intervention Programme in Sweden. Height, weight, demographics and selected cardiovascular risk factors were collected on each participant. Prevalences of obesity were calculated for the 40, 50 and 60 year olds from the cross-sectional studies between 1990 and 2004. In the longitudinal study, 10-year non-gain (lost weight or maintained body weight within 3% of baseline weight or weight gain (≥ 3% was calculated for individuals aged 30, 40, or 50 years at baseline. A multivariate logistic regression model was built to predict weight non-gain. Results There were 82,927 adults included in the cross-sectional studies which had an average annual participation rate of 63%. Prevalence of obesity [body mass index (BMI in kg/m2 ≥ 30] increased from 9.4% in 1990 to 17.5% in 2004, and 60 year olds had the highest prevalence of obesity. 14,867 adults with a BMI of 18.5–29.9 at baseline participated in the longitudinal surveys which had a participation rate of 74%. 5242 adults (35.3% were categorized as non-gainers. Older age, being female, classified as overweight by baseline BMI, later survey year, baseline diagnosis of diabetes, and lack of snuff use increased the chances of not gaining weight. Conclusion Educational efforts should be broadened to include those adults who are usually considered to be at low risk for weight gain – younger individuals, those of normal body weight, and those without health

  8. Associations between safety from crime, cycling, and obesity in a Dutch elderly population: results from the Longitudinal Aging Study Amsterdam.

    Science.gov (United States)

    Kremers, Stef P J; de Bruijn, Gert-Jan; Visscher, Tommy L S; Deeg, Dorly J H; Thomése, G C Fleur; Visser, Marjolein; van Mechelen, Willem; Brug, Johannes

    2012-01-01

    The objective of this cross-sectional study was to investigate differences in associations between crime rates, cycling, and weight status between people living in low and high socioeconomic status (SES) neighbourhoods. In total, 470 participants in the Longitudinal Aging Study Amsterdam were included (age: 63-70 y). Body height and weight were measured using a stadiometer and calibrated weight scale, respectively. Cycling behaviour was assessed in a face-to-face interview, and neighbourhood crime rates were assessed using data from police reports. Men residing in high SES neighbourhoods cycled more than males residing in low SES neighbourhoods. Cycling was negatively related to crime rates among both men and women living in low SES neighbourhoods. Among men living in low SES neighbourhoods, more cycling was associated with lower BMI. Interventions aiming to prevent obesity in older people may consider aiming at increasing bicycle use in lower SES neighbourhoods, but neighbourhood safety issues should be considered.

  9. Associations between Safety from Crime, Cycling, and Obesity in a Dutch Elderly Population: Results from the Longitudinal Aging Study Amsterdam

    Directory of Open Access Journals (Sweden)

    Stef P. J. Kremers

    2012-01-01

    Full Text Available The objective of this cross-sectional study was to investigate differences in associations between crime rates, cycling, and weight status between people living in low and high socioeconomic status (SES neighbourhoods. In total, 470 participants in the Longitudinal Aging Study Amsterdam were included (age: 63–70 y. Body height and weight were measured using a stadiometer and calibrated weight scale, respectively. Cycling behaviour was assessed in a face-to-face interview, and neighbourhood crime rates were assessed using data from police reports. Men residing in high SES neighbourhoods cycled more than males residing in low SES neighbourhoods. Cycling was negatively related to crime rates among both men and women living in low SES neighbourhoods. Among men living in low SES neighbourhoods, more cycling was associated with lower BMI. Interventions aiming to prevent obesity in older people may consider aiming at increasing bicycle use in lower SES neighbourhoods, but neighbourhood safety issues should be considered.

  10. Population size structure of non-native fishes along longitudinal gradients in a highly regulated Mediterranean basin.

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    Fátima Amat-Trigo

    2015-10-01

    Documented changes in fish size metrics at population levels can demonstrate trends in non-native fishes at basin scale, however, the collinearity with spatial gradients and the species-specific response could make it a difficult undertaking.

  11. The Effect of Intra- and Intergenerational Caregiving on Subjective Well-Being--Evidence of a Population Based Longitudinal Study among Older Adults in Germany.

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    André Hajek

    Full Text Available To examine whether intra- and intergenerational caregiving affect subjective well-being (SWB of the caregivers longitudinally.Data were drawn from the German Ageing Survey (DEAS, which is a population-based longitudinal study of individuals living in Germany aged 40 and over. The waves in 2002, 2008 and 2011 were used (with 10,434 observations. SWB was examined in a broad sense, covering affective (AWB and cognitive well-being (CWB, positive (PA and negative affect (NA as well as functional and mental health. While intragenerational caregiving was defined as providing care for spouse/partner, intergenerational caregiving was defined as providing care for mother, father, mother-in-law, father-in-law, partner's mother or partner's father.Fixed effects regressions adjusting for sociodemographic factors, social network, self-efficacy and morbidity showed that intergenerational informal care did not affect the various SWB outcome measures. Intragenerational caregiving affected CWB (women and mental health (total sample and men, whereas it did not affect the other outcome variables.Our findings highlight the importance of intragenerational caregiving for mental health (men and cognitive well-being (women. Consequently, interventions to avoid mental illness due to intragenerational caregiving are urgently needed.

  12. The Black-White Achievement Gap Revisited Revisitando la brecha en el rendimiento de estudiantes negros y blancos Revisitando a defasagem de rendimento academico dos estudantes negros e brancos

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    Henry Braun

    2010-09-01

    Full Text Available This study examines trends in Black student achievement and in the Black-White achievement gap over the period 2000 to 2007, employing data from ten states drawn from the NAEP Grade 8 mathematics assessments. Results are obtained for three levels of aggregation: the state, school poverty stratum within the state, and schools within poverty stratum. In addition, information on the ten states’ education policies for the period 1998 to 2005 was compiled. States relative ranks on the overall strength of their reform efforts were compared to their relative ranks with respect to their success in improving Black student achievement and in reducing the Black- White achievement gap. This study constitutes an extension of earlier work that considered the same issues for the period 1992 to 2000 and, thus, offers a unique comparison between the pre-NCLB era and the present one. Although the ten states certainly differed in their outcomes, the general picture at all three levels of aggregation is quite clear: The achievement gaps are substantial and the introduction of federally mandated high stakes test-based accountability through No Child Left Behind has had a very modest impact on the rates of improvement for Black students and on the pace of reductions in the achievement gaps between Black students and White students. Moreover, there was only a weak association between states’ policy rankings and their rankings related to test results. It appears there is a need for both fresh thinking on education reform and a more concerted effort to collect comprehensive longitudinal information on states' education policies.
    Este estudio examina las tendencias en el rendimiento académico de estudiantes negros y la brecha en el rendimiento de los estudiantes negros y blancos en el período 2000 a 2007, utilizando datos de las evaluaciones NAEP de Matemáticas para el octavo grado en diez estados. Se obtuvieron resultados para tres niveles de agregacio

  13. Brain Amyloid Deposition and Longitudinal Cognitive Decline in Nondemented Older Subjects: Results from a Multi-Ethnic Population.

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    Yian Gu

    Full Text Available We aimed to whether the abnormally high amyloid-β (Aβ level in the brain among apparently healthy elders is related with subtle cognitive deficits and/or accelerated cognitive decline.A total of 116 dementia-free participants (mean age 84.5 years of the Washington Heights Inwood Columbia Aging Project completed 18F-Florbetaben PET imaging. Positive or negative cerebral Aβ deposition was assessed visually. Quantitative cerebral Aβ burden was calculated as the standardized uptake value ratio in pre-established regions of interest using cerebellar cortex as the reference region. Cognition was determined using a neuropsychological battery and selected tests scores were combined into four composite scores (memory, language, executive/speed, and visuospatial using exploratory factor analysis. We examined the relationship between cerebral Aβ level and longitudinal cognition change up to 20 years before the PET scan using latent growth curve models, controlling for age, education, ethnicity, and Apolipoprotein E (APOE genotype.Positive reading of Aβ was found in 41 of 116 (35% individuals. Cognitive scores at scan time was not related with Aβ. All cognitive scores declined over time. Aβ positive reading (B = -0.034, p = 0.02 and higher Aβ burden in temporal region (B = -0.080, p = 0.02 were associated with faster decline in executive/speed. Stratified analyses showed that higher Aβ deposition was associated with faster longitudinal declines in mean cognition, language, and executive/speed in African-Americans or in APOE ε4 carriers, and with faster memory decline in APOE ε4 carriers. The associations remained significant after excluding mild cognitive impairment participants.High Aβ deposition in healthy elders was associated with decline in executive/speed in the decade before neuroimaging, and the association was observed primarily in African-Americans and APOE ε4 carriers. Our results suggest that measuring cerebral Aβ may give us

  14. Same-Sex Couples' Decisions and Experiences of Marriage in the Context of Minority Stress: Interviews From a Population-Based Longitudinal Study.

    Science.gov (United States)

    Rostosky, Sharon S; Riggle, Ellen D B; Rothblum, Esther D; Balsam, Kimberly F

    2016-08-01

    In the emerging context of marriage equality, it is important to explore the reasons for and experience of marriage for long-term same-sex couples, including the role of minority stress. In Wave 3 of the population-based, longitudinal CUPPLES Study we interviewed 21 long-term same-sex couples (14 female, 7 male) who resided in 12 different states and who were legally married. Couple members ranged in age from 37 to 84 and reported being together as a couple from 15 to 41 years. Seven couples lived in states that did not recognize their marriage at the time of the interview. Legal protection and social validation emerged as the two primary domains that captured couples' lived experiences of marriage. Minority stress experiences emerged in the narratives in the context of couples' long-term commitment, the availability of civil marriage, and couples' participation in activist efforts on behalf of marriage equality for themselves and others.

  15. From epidemiology to daily life: linking daily life stress reactivity to persistence of psychotic experiences in a longitudinal general population study.

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    Dina Collip

    Full Text Available Subclinical psychotic experiences at the level of the general population are common, forming an extended psychosis phenotype with clinical psychosis. Persistence of subclinical experiences is associated with transition to later mental disorder. Increased daily life stress reactivity is considered an endophenotype for psychotic disorders. We examined, in a longitudinal framework, whether baseline momentary assessment markers of stress reactivity would predict persistence of subclinical psychotic experiences over time. In a general population sample of female twins (N = 566, the Experience Sampling Method (ESM; repetitive random sampling of momentary emotions, psychotic experiences and context was used to assess (emotional and psychotic daily life stress reactivity. Persistence of subclinical psychotic experiences was based on the Community Assessment of Psychic Experiences (CAPE, assessed three times over 14 months post-baseline. It was investigated whether baseline daily life emotional and psychotic stress reactivity predicted persistence of psychotic experiences over time. Higher levels of emotional stress reactivity (a decrease in positive and an increase in negative affect in response to stress, and increased psychotic reactivity to daily stress was found in individuals with persistent psychotic experiences over time compared to individuals with transient psychotic experiences. The results suggest that markers of daily life stress reactivity may predict "macro-level" persistence of normally transient expression of psychotic liability over time. Linking daily life markers of altered reactivity in terms of emotions and psychotic experiences to longitudinal persistence of psychotic experiences, associated with increased risk of transition to overt mental disorder, may contribute to earlier and more accurate diagnosis of risk.

  16. Associations between cognitive abilities and life satisfaction in the oldest-old. Results from the longitudinal population study Good Aging in Skåne

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    Enkvist Å

    2013-07-01

    Full Text Available Åsa Enkvist, Henrik Ekström, Sölve Elmståhl Department of Health Sciences, Division of Geriatric Medicine, Lund University, Skåne University Hospital, Malmö, Sweden Introduction: Studies on the associations between cognitive abilities and life satisfaction (LS in the oldest-old are few. The aim of this study was to explore whether abilities in six different cognitive domains could predict LS in the oldest-old 3 years later. Methods: The study population consisted of 681 individuals aged 78–98 years, drawn from the longitudinal population study “Good Aging in Skåne,” which is part of a national survey (The Swedish National Study on Aging and Care. Scores on 13 cognitive tests were related to scores on Neugartens’ LS index A (LSI-A 3 years later. The cognitive tests were added into six different cognitive domains. A multiple regression analysis was constructed for each cognitive domain separately, with scores on the LSI-A as the dependent variable. The model was adjusted stepwise for sex, age, education, functional capacity, and depressive mood. Results: Significant correlations were found between digit cancellation, word recall, verbal fluency (VF A, VF animals, VF occupations, and mental rotations at baseline, as well as LSI-A at follow-up. The domains of spatial abilities (B = 0.453, P = 0.014 and processing speed (B = 0.118, P = 0.020 remained significantly associated with LSI-A 3 years later after adjustment. Conclusion: The cognitive domains of spatial abilities and processing speed predicted LS 3 years later in the oldest-old. Clinical implications are discussed. Keywords: oldest-old, life satisfaction, longitudinal, crystallized and fluid intelligence, cognition

  17. Associations between functional ability and life satisfaction in the oldest old: results from the longitudinal population study Good Aging in Skåne

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    Enkvist Å

    2012-08-01

    Full Text Available Åsa Enkvist, Henrik Ekström, Sölve ElmståhlDepartment of Health Sciences, Lund University, Malmö University Hospital, Malmö, SwedenObjectives: To describe change in functional ability in the oldest-old population during 3 years and examine its relation to life satisfaction (LS. A total of 681 individuals aged 78 and older from the population-based study Good Aging in Skåne took part.Methods: Functional ability was assessed using Sonn and Åsberg's Activities of Daily Living (ADL scale and related to LS assessed by Neugarten et al's Life Satisfaction Index A (LSI-A.Results: Fifty-one percent of 87–93-year-olds reported ADL decline during 3 years. Individuals reporting impaired ADL had a mean LSI-A value of 23.0 compared to 26.4 in those unchanged. ADL decline had a stronger negative effect on LS in the younger group (78–84 years, r = 0.207, P < 0.001. In a multiple regression model, one score's decline in ADL capacity corresponded to 1.5 scores lower LS (P < 0.001.Discussion: Effort put into keeping the oldest old on a high level of functional ability has the potential to maintain the LS of this population.Keywords: life satisfaction, functional ability, longitudinal, oldest old

  18. Life satisfaction (LS) and symptoms among the oldest-old: results from the longitudinal population study called Good Aging in Skåne (GÅS).

    Science.gov (United States)

    Enkvist, Asa; Ekström, Henrik; Elmståhl, Sölve

    2012-01-01

    Studies on the prevalence of symptoms in the general population and its' relation to LS in the oldest-old are to our knowledge non-existent. The aim of this study was to describe the frequency and experienced severity of elderly subjects' reported symptoms and how symptoms are related to LS. The study population consisted of 681 individuals aged 78-93 years, drawn from the longitudinal population study, GÅS, part of a national survey (SNAC). Scores on the life satisfaction index were related to scores on a modified version of the Göteborg Quality of Life (GQoL) instrument, covering 32 common symptoms. Musculo-skeletal symptoms like pain were reported by 74%, 80% had depressive symptoms and 68% general fatigue. Less than 6% of men and women reported no metabolic symptoms or symptoms related to the head. In a multiple regression model it was shown that four groups of symptoms could significantly predict LS 3 years later: depression, tension, GI-symptoms and musculo-skeletal symptoms. The clinical implication of this study is that careful attention should be paid to the elderly patients' complaints concerning symptoms in the above areas since this has the potential to significantly increase the patients' satisfaction with life.

  19. Consenting to health record linkage: evidence from a multi-purpose longitudinal survey of a general population

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    Knies Gundi

    2012-03-01

    Full Text Available Abstract Background The British Household Panel Survey (BHPS is the first long-running UK longitudinal survey with a non-medical focus and a sample covering the whole age range to have asked for permission to link to a range of administrative health records. This study determines whether informed consent led to selection bias and reflects on the value of the BHPS linked with health records for epidemiological research. Methods Multivariate logistical regression is used, with whether the respondent gave consent to data linkage or not as the dependent variable. Independent variables were entered as four blocks; (i a set of standard demographics likely to be found in most health registration data, (ii a broader set of socio-economic characteristics, (iii a set of indicators of health conditions and (iv information about the use of health services. Results Participants aged 16-24, males and those living in England were more likely to consent. Consent is not biased with respect to socio-economic characteristics or health. Recent users of GP services are underrepresented among consenters. Conclusions Whilst data could only be linked for a minority of BHPS participants, the BHPS offers a great range of information on people's life histories, their attitudes and behaviours making it an invaluable source for epidemiological research.

  20. Prevalence of Tourette Syndrome and Chronic Tics in the Population-Based Avon Longitudinal Study of Parents and Children Cohort

    Science.gov (United States)

    Scharf, Jeremiah M.; Miller, Laura L.; Mathews, Carol A.; Ben-Shlomo, Yoav

    2012-01-01

    Objective: Recent epidemiologic studies have demonstrated that Tourette syndrome (TS) and chronic tic disorder (CT) are more common than previously recognized. However, few population-based studies have examined the prevalence of co-occurring neuropsychiatric conditions such as obsessive-compulsive disorder (OCD) and…

  1. Longitudinal associations between physical load and chronic low back pain in the general population: the Doetichem Cohort Study

    NARCIS (Netherlands)

    Oostrom, S.H.; Verschuren, M.; Vet, de H.C.; Boshuizen, H.C.; Picavet, H.S.

    2012-01-01

    Study Design. Prospective cohort study. Objective. We explored long-term associations between physical load exposure and chronic low back pain (LBP) using data from an ongoing population-based cohort study. Summary of Background Data. Physical load in work or daily life is often studied in relation

  2. A 20-year longitudinal study of Plasmodium ovale and Plasmodium malariae prevalence and morbidity in a West African population.

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    Clémentine Roucher

    Full Text Available BACKGROUND: Plasmodium ovale and Plasmodium malariae have long been reported to be widely distributed in tropical Africa and in other major malaria-endemic areas of the world. However, little is known about the burden caused by these two malaria species. METHODS AND FINDINGS: We did a longitudinal study of the inhabitants of Dielmo village, Senegal, between June, 1990, and December, 2010. We monitored the inhabitants for fever during this period and performed quarterly measurements of parasitemia. We analyzed parasitological and clinical data in a random-effect logistic regression model to investigate the relationship between the level of parasitemia and the risk of fever and to establish diagnostic criteria for P. ovale and P. malariae clinical attacks. The prevalence of P. ovale and P. malariae infections in asymptomatic individuals were high during the first years of the project but decreased after 2004 and almost disappeared in 2010 in relation to changes in malaria control policies. The average incidence densities of P. ovale and P. malariae clinical attacks were 0.053 and 0.093 attacks per person per year in children <15 years and 0.024 and 0.009 attacks per person per year in adults ≥ 15 years, respectively. These two malaria species represented together 5.9% of the malaria burden. CONCLUSIONS: P. ovale and P. malariae were a common cause of morbidity in Dielmo villagers until the recent dramatic decrease of malaria that followed the introduction of new malaria control policies. P. ovale and P. malariae may constitute an important cause of morbidity in many areas of tropical Africa.

  3. Disability and all-cause mortality in the older population: evidence from the English Longitudinal Study of Ageing.

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    Pongiglione, Benedetta; De Stavola, Bianca L; Kuper, Hannah; Ploubidis, George B

    2016-08-01

    Despite the vast body of literature studying disability and mortality, evidence to support their association is scarce. This work investigates the role of disability in explaining all-cause mortality among individuals aged 50+ who participated in the English Longitudinal Study of Aging. The aim is to explain the gender paradox in health and mortality by analysing whether the association of disability with mortality differs between women and men. Disability was conceived following the International Classification of Functioning, Disability and Health (ICF), proposed by the WHO, that conceptualizes disability as a combination of three components: impairment, activity limitation and participation restriction. Latent variable models were used to identify domain-specific factors and general disability. The association of the latter with mortality up to 10 years after enrolment was estimated using discrete-time survival analysis. Our work confirms the validity of the ICF framework and finds that disability is strongly associated with mortality, with a time-varying effect among men, and a smaller constant effect for women. Adjusting for demographic, socioeconomic and behavioural factors attenuated the association for both sexes, but overall the effects remained high and significant. These findings confirm the existence of gender paradox by showing that, when affected by disability, women survive longer than men, although if men survive the first years they appear to become more resilient to disability. Sensitivity analyses suggested that the gender paradox cannot be solely explained by gender-specific health conditions: there must be other mechanisms acting within the pathway between disability and mortality that need to be explored.

  4. Population model of longitudinal FEV1 data in asthmatics: meta-analysis and predictability of placebo response.

    Science.gov (United States)

    Marostica, Eleonora; Russu, Alberto; Yang, Shuying; De Nicolao, Giuseppe; Zamuner, Stefano; Beerahee, Misba

    2014-12-01

    Asthma is an obstructive lung disease where the mechanism of disease progression is not fully understood hence motivating the use of empirical models to describe the evolution of the patient's health state. With reference to placebo response, measured in terms of FEV1 (Forced Expiratory Volume in 1 s), a range of empirical models taken from the literature were compared at a single trial level. In particular, eleven GSK trials lasting 12 weeks in mild-to-moderate asthma were used for the modelling of longitudinal placebo responses. Then, the chosen exponential model was used to carry out an individual participant data meta-analysis on eleven trials. A covariate analysis was also performed to find relevant covariates in asthma to be accounted for in the meta-analysis model. Age, gender, and height were found statistically significant (e.g. the taller the patients the higher the FEV1, the older the patients the lower the FEV1, and females have lower FEV1). By truncating each trial at week 4, the predictive properties of the meta-analysis model were also investigated, showing its ability to predict long-term FEV1 response from truncated trials. Summarizing, the study suggests that: (i) the exponential model effectively describes the placebo response; (ii) the meta-analysis approach may prove helpful to simulate new trials as well as to reduce trial duration in view of its predictive properties; (iii) the inclusion of available covariates within the meta-analysis model provides a reduction of the inter-individual variability.

  5. Neuropsychological Decline in Schizophrenia from the Premorbid to Post-Onset Period: Evidence from a Population-Representative Longitudinal Study

    Science.gov (United States)

    Meier, Madeline H.; Caspi, Avshalom; Reichenberg, Abraham; Keefe, Richard S.E.; Fisher, Helen; Harrington, HonaLee; Houts, Renate; Poulton, Richie; Moffitt, Terrie

    2013-01-01

    Objective Despite widespread belief that neuropsychological decline is a cardinal feature of the progression from the premorbid to the chronic form of schizophrenia, few longitudinal studies have examined change in neuropsychological functioning from before to after the onset of schizophrenia. We addressed the following unresolved questions: Is neuropsychological decline generalized versus confined to particular mental functions? Is neuropsychological decline unique to schizophrenia? Do individuals with schizophrenia also have cognitive problems in everyday life? Method Participants were members of a representative cohort of 1,037 individuals born in Dunedin, New Zealand between 1972-73 and followed prospectively to age 38, with 95% retention. Assessment of IQ and other specific neuropsychological functions was conducted at ages 7-13, before the onset of schizophrenia, and again at age 38. Informants also reported on cognitive problems at age 38. Results Individuals with schizophrenia showed decline in IQ as well as a range of different mental functions, particularly those tapping processing speed, learning, executive functioning, and motor functioning. There was little evidence of decline in verbal abilities or delayed memory, however, and the developmental progression of deficits in schizophrenia differed across mental functions. Processing speed deficits increased gradually from childhood to beyond the early teen years, whereas verbal deficits emerged early but remained static through midlife. Neuropsychological decline was specific to schizophrenia, as no evidence of decline was apparent among individuals with persistent depression, children with mild cognitive impairment, individuals matched on childhood risk factors for schizophrenia, and psychiatrically healthy individuals. Informants also reported cognitive problems for individuals diagnosed with schizophrenia. Conclusion There is substantial neuropsychological decline in schizophrenia from the premorbid to

  6. Natural History of Dependency in the Elderly: A 24-Year Population-Based Study Using a Longitudinal Item Response Theory Model.

    Science.gov (United States)

    Edjolo, Arlette; Proust-Lima, Cécile; Delva, Fleur; Dartigues, Jean-François; Pérès, Karine

    2016-02-15

    We aimed to describe the hierarchical structure of Instrumental Activities of Daily Living (IADL) and basic Activities of Daily Living (ADL) and trajectories of dependency before death in an elderly population using item response theory methodology. Data were obtained from a population-based French cohort study, the Personnes Agées QUID (PAQUID) Study, of persons aged ≥65 years at baseline in 1988 who were recruited from 75 randomly selected areas in Gironde and Dordogne. We evaluated IADL and ADL data collected at home every 2-3 years over a 24-year period (1988-2012) for 3,238 deceased participants (43.9% men). We used a longitudinal item response theory model to investigate the item sequence of 11 IADL and ADL combined into a single scale and functional trajectories adjusted for education, sex, and age at death. The findings confirmed the earliest losses in IADL (shopping, transporting, finances) at the partial limitation level, and then an overlapping of concomitant IADL and ADL, with bathing and dressing being the earliest ADL losses, and finally total losses for toileting, continence, eating, and transferring. Functional trajectories were sex-specific, with a benefit of high education that persisted until death in men but was only transient in women. An in-depth understanding of this sequence provides an early warning of functional decline for better adaptation of medical and social care in the elderly.

  7. Evaluation of the Finnish Diabetes Risk Score to predict type 2 diabetes mellitus in a Colombian population: A longitudinal observational study

    Institute of Scientific and Technical Information of China (English)

    Diego; Gomez-Arbelaez; Laura; Alvarado-Jurado; Miguel; Ayala-Castillo; Leonardo; Forero-Naranjo; Paul; Anthony; Camacho; Patricio; Lopez-Jaramillo

    2015-01-01

    AIM: To assess the performance of the Finnish Diabetes Risk Score(FINDRISC) questionnaire for detecting and predicting type 2 diabetes mellitus(DM2) in a Colombian population.METHODS: This is a longitudinal observational study conducted in Floridablanca, Colombia. Adult subjects(age ≥ 35 years) without known diabetes, were included. A modified version of FINDRISC was completed, and the glycemia values from all the subjects were collected from the hospital’s database. Firstly, a cross-sectional analysis was performed and then, the subsample of prediabetic participants was followed for diabetes incidence. RESULTS: A total of 772 subjects were suitable for the study. The overall prevalence of undiagnosed DM2 was 2.59%, and the incidence of DM2 among the prediabetic participants was 7.5 per 100 person-years after a total of 265257 person-years follow-up. The FINDRISC at baseline was significantly associated with undiagnosed and incident DM2. The area under receiver operating characteristics curve of the FINDRISC score for detecting undiagnosed DM2 in both men and women was 0.7477 and 0.7175, respectively; and for predicting the incidence of DM2 among prediabetics was 71.99% in men and 67.74% in women. CONCLUSION: The FINDRISC questionnaire is a useful screening tool to identify cross-sectionally unknown DM2 and to predict the incidence of DM2 among prediabetics in the Colombian population.

  8. The association of cancer survival with four socioeconomic indicators: a longitudinal study of the older population of England and Wales 1981–2000

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    Young Harriet

    2007-01-01

    Full Text Available Abstract Background Many studies have found socioeconomic differentials in cancer survival. Previous studies have generally demonstrated poorer cancer survival with decreasing socioeconomic status but mostly used only ecological measures of status and analytical methods estimating simple survival. This study investigate socio-economic differentials in cancer survival using four indicators of socioeconomic status; three individual and one ecological. It uses a relative survival method which gives a measure of excess mortality due to cancer. Methods This study uses prospective record linkage data from The Office for National Statistics Longitudinal Study for England and Wales. The participants are Longitudinal Study members, recorded at census in 1971 and 1981 and with a primary malignant cancer diagnosed at age 45 or above, between 1981 and 1997, with follow-up until end 2000. The outcome measure is relative survival/excess mortality, compared with age and sex adjusted survival of the general population. Relative survival and Poisson regression analyses are presented, giving models of relative excess mortality, adjusted for covariates. Results Different socioeconomic indicators detect survival differentials of varying magnitude and definition. For all cancers combined, the four indicators show similar effects. For individual cancers there are differences between indicators. Where there is an association, all indicators show poorer survival with lower socioeconomic status. Conclusion Cancer survival differs markedly by socio-economic status. The commonly used ecological measure, the Carstairs Index, is adequate at demonstrating socioeconomic differentials in survival for combined cancers and some individual cancers. A combination of car access and housing tenure is more sensitive than the ecological Carstairs measure at detecting socioeconomic effects on survival – confirming Carstairs effects where they occur but additionally identifying

  9. Homofilia, Selección e Influencia en un Estudio Longitudinal de Drogas en Población Escolar Homophily, Selection, and Influence in a Longitudinal Study of Drugs in School Population

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    Eduardo Valenzuela

    2011-11-01

    Full Text Available Este estudio pretende establecer los niveles de homogeneidad de pares -a veces llamada homofilia en la literatura especializada- que se encuentra en el uso de tabaco, alcohol y marihuana en relaciones de amistad en la adolescencia temprana. Se utilizan datos longitudinales que identifican diadas de amistad entre alumnos de 7° y 8° grado provenientes de una muestra representativa de población escolarizada de la Región Metropolitana de Chile. También se ofrecen estimaciones sobre el origen de la homofilia observada, sea como resultado de procesos de selección, en los que la similitud precede a la amistad, o de influencia, en la que, por el contrario, la amistad conduce a la concordancia de pares. Los resultados muestran que la iniciación en el uso de drogas se realiza en ambientes moderadamente concordantes y que los efectos de influencia predominan sobre los de selección.This study seeks to establish levels of peer homogeneity -sometimes called homophily in the literature- in the use of tobacco, alcohol, and marijuana in friendship relations in early adolescence. Longitudinal data from a representative sample of school population of the Metropolitan Region of Chile was used to identify friendship dyads between students in 7th and 8th grades. Additionally, some estimates about the origin of the observed homophily are provided, as a result of selection processes in which similarity precedes friendship or, alternatively, as a result of influence processes where friendship leads to matching pairs. The results show that initiation into drugs takes place in environments that are moderately homogeneous and that influence effects are more important than selection effects.

  10. Comparison of stayers, dropouts, and newcomers in a longitudinal population study of asthma and bronchial hyperresponsiveness: introduction of bias?

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    Ulrik, C S

    1995-01-01

    A random sample of children and adolescents from the general population in Copenhagen, Denmark, has been examined twice (6 years apart) with respect to asthma, allergy, and nonspecific bronchial hyperresponsiveness. To investigate potential bias resulting from loss of baseline subjects at follow-up (dropout bias) and bias resulting from subjects entering the study at the follow-up stage (newcomer bias), stayers (subjects who participated in both examinations) were compared to dropouts and newcomers, respectively. The sample consisted of 983 subjects (aged 7-17 years at the time of the baseline study), of whom 408 (199 boys) participated in both examinations (stayers), 119 (62 boys) in the baseline study only (dropouts), and 257 (124 boys in the follow-up study only (newcomers). Thus, a total of 784 subjects (80% of the sample) were examined either once or twice. At baseline dropouts did not differ from stayers with respect to anthropometric data, smoking habits, pulmonary function, or prevalence of positive skin prick tests, bronchial hyperresponsiveness, asthma, and allergic diseases. Likewise, these variables for newcomers were not different from those of the stayers apart from a significantly higher smoking rate in newcomers (45% vs. 32%, p = 0.003). Based on these findings and the high overall response rate, it seems reasonable to assume that the group of stayers is representative of the whole sample, apart from an underestimation of the number of smokers and, therefore, an underestimation of the risks associated with smoking.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Parental gender equality and use of oral contraceptives among young women: A longitudinal, population-based study in Sweden

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    Mamunur Rashid

    2014-01-01

    Full Text Available Background: Little is known about how parental gender equality early in their children lives can influence daughters′ decision to use contraceptive pills. Aim: The study aimed at exploring whether maternal working time and paternity leave in Sweden during the first two years of their daughters′ lives is associated with the use of oral contraceptives when they are adolescents or young adults. Materials and Methods: The study population was selected from a cohort of all Swedish fathers and mothers who had their first child together between 1988 and 1989 (n = 57,520 family units. Multivariate logistic regression was used to estimate the association. Results: Mothers′ longer working time was mildly associated with daughters′ oral contraceptive pill use, though no clear trend was observed. Longer paternity leave periods (>30 days were not associated with use of oral contraceptives among their daughters, but 1-30 day periods showed a mild positive association. Conclusion: For maternal working time, there seems to be an association, but trends by working hours are not clear. There is no clear association between paternity leave during the first two years of their daughters′ life and the use of oral contraceptives when they are adolescents and young adults.

  12. Effect of COMT Val158Met polymorphism on personality traits and educational attainment in a longitudinal population representative study.

    Science.gov (United States)

    Lehto, K; Akkermann, K; Parik, J; Veidebaum, T; Harro, J

    2013-10-01

    The COMT Val158Met polymorphism has been associated with anxiety and affective disorders, but its effect on anxiety-related personality traits varies between studies. Our purpose was to investigate the effect of COMT Val158Met on personality traits from adolescence to young adulthood in a population representative Caucasian birth cohort. Also its association with educational attainment and anxiety and mood disorders by the age 25 were examined. This analysis is based on the older cohort of the Estonian Children Personality Behavior and Health Study (original number of subjects 593). The personality traits were assessed when the participants were 15, 18 and 25 years old. COMT Val158Met had an effect on Neuroticism in females by age 25 (p=0.001, Bonferroni-corrected for five traits), whereas female Val homozygotes scored the highest. In addition, the Conscientiousness scores of subjects with Val/Val genotype were decreasing in time, being the lowest by the age 25 (p=0.006, Bonferroni-corrected for five traits). By the age 25, males with the Val/Met genotype had mainly secondary or vocational education, whereas female heterozygotes mostly had obtained or were obtaining university education. COMT Val158Met was not associated with anxiety or mood disorders in either gender. These results suggest that genes affecting dopamine system are involved in the development of personality traits and contribute to educational attainment.

  13. Multiple births and maternal mental health from pregnancy to 5 years after birth: A longitudinal population-based cohort study

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    Eivind Ystrom

    2014-12-01

    Full Text Available Background: There is a lack of population-based studies on multiple births and maternal mental health. Having a high-risk pregnancy by bearing two or more children is a stressful life event, and the challenges of parenting two or more children probably also lead to a high level of parental stress. There are a few results on multiple births and maternal mental health from studies on in vitro fertilization samples. The only previous cohort study on multiple birth and maternal mental health included a single measure of depressive symptoms at 9 months postpartum. We aim to estimate the relative risk for depression and anxiety after multiple birth in a population-based prospective cohort study while adjusting for factors prior and subsequent to fertilization.Methods: We used data from 87,807 pregnancies included in the Norwegian Mother and Child Cohort study. Information on multiple birth was retrieved from the Norwegian Medical Birth Registry, and maternal mental health was assessed at 17th and 30th week of gestation and 0.5, 1.5, 3, and 5 years postpartum. There were 1,842 plural births included in the study (i.e. 1,821 twin births and 21 higher order births. We predicted maternal mental health at each time point, subsequently adjusting for 1 factors prior to fertilization (e.g. maternal age and in vitro fertilization; 2 factors during pregnancy (e.g. hypertensive states; 3 factors at delivery (e.g. cesarean section; 4 child-related postnatal complications (e.g. intracranial hemorrhage; and 5 concurrent depression or anxiety after pregnancy.Results: Adjusted for antecedents of plural birth, mothers expecting a plural birth had a normal risk for anxiety (RR=1.05; 95% CI 0.92-1.20 and depression (RR=1.02; 95% CI 0.89-1.16 at 17th week of gestation. However, plural birth was associated with maternal depression at 1.5, 3, and 5 years postpartum and maternal anxiety at 3 years postpartum. The trend was for the association to increase across time, and

  14. Influence of early life factors on body mass index trajectory during childhood: a population-based longitudinal analysis in the Western Brazilian Amazon.

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    Lourenço, Barbara H; Villamor, Eduardo; Augusto, Rosângela A; Cardoso, Marly A

    2015-04-01

    Low- to middle-income countries may experience the occurrence of a dual burden of under and overnutrition. To better understand the overall progression of body mass index (BMI) during childhood, we estimated average BMI-for-age z-score (BAZ) growth curves in a population-based longitudinal study of 255 children living in the Brazilian Amazon. Children were aged 0.1-5.5 years at recruitment (2003). We collected data on socio-economic and maternal characteristics, children's birthweight and infant feeding practices. Child anthropometric measurements were taken in 2003, 2007 and 2009. BAZ differences among categories of exposure variables were calculated at 6 and 12 months, and 2, 7 and 10 years. At baseline, the mean (standard deviation) age was 2.6 (1.4) years; 12.9% were overweight and 3.9% thin. After adjustment, mean BAZ estimates were mostly negative. Boys were close to the median value for BAZ until 12 months, whereas girls were below the median (P=0.05). Children from households above the wealth median were 0.36 z- and 0.49 z-less underweight than poorer children at 7 and 10 years, respectively (Pchildhood. Although excessive weight gain is a public health concern, it is critical to restrict inequities, while promoting healthier growth in developing countries.

  15. [Infant mortality among the black population of Brazil, 1960-1980].

    Science.gov (United States)

    Tamburo, E M

    1987-08-01

    This is a comparative analysis of infant mortality trends for the period 1960-1980 among blacks, whites, and mixed race population groups in Brazil, based on data from official sources. The impact of marital and educational status is considered. The study is confined to the states of Bahia, Minas Gerais, Rio Grande do Sul, and Sao Paulo. An appendix on the methodological issues involved is included.

  16. Cross-sectional study of sleep quantity and quality and amnestic and non-amnestic cognitive function in an ageing population: the English Longitudinal Study of Ageing (ELSA.

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    Michelle A Miller

    Full Text Available BACKGROUND: The aim was to investigate the association between sleep disturbances and cognitive function in younger and older individuals from an ageing population. METHODS: 3,968 male and 4,821 female white participants, aged 50 years and over, from the English Longitudinal Study of Ageing (ELSA were studied. Information on sleep quality and quantity as well as both amnestic (memory, ACF and non-amnestic (non-memory, nACF function was available at Wave 4 (2008. Analysis of covariance was used to evaluate the relationship between sleep and cognitive function. RESULTS: After adjustment for multiple confounders in the younger group (50-64 years duration of sleep explained 15.2% of the variance in ACF (p = 0.003 and 20.6% of nACF (p = 0.010. In the older group (65+ years the estimates were 21.3% (p<0.001 and 25.6% (p<0.001, respectively. For sleep quality, there was a statistically significant association between sleep quality and both ACF (p<0.001 and nACF (p<0.001 in the older age group, but not in the younger age group (p = 0.586 and p = 0.373, respectively; interaction between age and sleep quality in the study sample including both age groups: p<0.001 for ACF and p = 0.018 for nACF. Sleep quality explained between 15.1% and 25.5% of the variance in cognition. The interaction with age was independent of duration of sleep. At any level of sleep duration there was a steeper association between sleep quality and ACF in the older than the younger group. CONCLUSIONS: The associations between sleep disturbances and cognitive function vary between younger and older adults. Prospective studies will determine the temporal relationships between sleep disturbances and changes in cognition in different age groups.

  17. Health-related factors correlate with behavior trends in physical activity level in old age: longitudinal results from a population in São Paulo, Brazil

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    Ribeiro Manoel CSA

    2010-11-01

    Full Text Available Abstract Background Physical inactivity in leisure time is common among elderly in Brazil and this finding is particularly alarming considering that this population is greatly affected by chronic diseases. The identification of health factors that influence physical activity level (PAL will help in the development of strategies for increasing PAL older adults. The current research aimed to identify variables that independently affect behavior trends in PAL over the course of two years among elderly. Methods A survey entitled the Epidoso Project ("Epidemiology of aging" studied 1,667 community-based older individuals in São Paulo city, Brazil over the course of two years. Physical activity level was determined through questions about frequency and duration of physical activities. Body Mass Index was calculated; functional capacity was assessed through the ADL (activities of daily living scale; cognition was assessed by Mini-Mental State Examination; and mental health was assessed through the Dysthymia Screening. Experiences of falls and fractures were also assessed. Subjects were divided into three groups according to their self-report of Physical Activity Level: a - Regularly Active; b - Insufficiently Active and c - Physically Inactive. Behavior trends in PAL were also measured after two years. Multivariate regression model methodology was used to test associations longitudinally. Results Results from the final model demonstrated that the risk of a not favorable behavior trend in PAL, which included the group who remained physically inactive and the group that displayed decreased PAL, in this cohort of older adults was significantly increased if the individual was female (OR = 2.50; 95% CI = 1.60-3.89; P , older (80 y vs. 65 y, OR = 6.29, 95% CI = 2.69-14.67; P , dependent on help from others for activities in the ADL scale (moderate-severe = 4-7+ vs. 0 ADLs (OR = 2.25, 95% CI = 1.20-4.21; P or had experienced a history of falls with

  18. Racial disparities in diabetes mortality in the 50 most populous US cities.

    Science.gov (United States)

    Rosenstock, Summer; Whitman, Steve; West, Joseph F; Balkin, Michael

    2014-10-01

    While studies have consistently shown that in the USA, non-Hispanic Blacks (Blacks) have higher diabetes prevalence, complication and death rates than non-Hispanic Whites (Whites), there are no studies that compare disparities in diabetes mortality across the largest US cities. This study presents and compares Black/White age-adjusted diabetes mortality rate ratios (RRs), calculated using national death files and census data, for the 50 most populous US cities. Relationships between city-level diabetes mortality RRs and 12 ecological variables were explored using bivariate correlation analyses. Multivariate analyses were conducted using negative binomial regression to examine how much of the disparity could be explained by these variables. Blacks had statistically significantly higher mortality rates compared to Whites in 39 of the 41 cities included in analyses, with statistically significant rate ratios ranging from 1.57 (95 % CI: 1.33-1.86) in Baltimore to 3.78 (95 % CI: 2.84-5.02) in Washington, DC. Analyses showed that economic inequality was strongly correlated with the diabetes mortality disparity, driven by differences in White poverty levels. This was followed by segregation. Multivariate analyses showed that adjusting for Black/White poverty alone explained 58.5 % of the disparity. Adjusting for Black/White poverty and segregation explained 72.6 % of the disparity. This study emphasizes the role that inequalities in social and economic determinants, rather than for example poverty on its own, play in Black/White diabetes mortality disparities. It also highlights how the magnitude of the disparity and the factors that influence it can vary greatly across cities, underscoring the importance of using local data to identify context specific barriers and develop effective interventions to eliminate health disparities.

  19. Repeatability and Minimal Detectable Change in Longitudinal Median Nerve Excursion Measures During Upper Limb Neurodynamic Techniques in a Mixed Population: A Pilot Study Using Musculoskeletal Ultrasound Imaging.

    Science.gov (United States)

    Paquette, Philippe; Lamontagne, Martin; Higgins, Johanne; Gagnon, Dany H

    2015-07-01

    This study determined test-retest reliability and minimum detectable change in longitudinal median nerve excursion during upper limb neurodynamic tests (ULNTs). Seven participants with unilateral or bilateral carpal tunnel syndrome and 11 healthy participants were randomly tested with two ULNTs (i.e., tensioner and slider). Each ULNT was performed three times each at 45° and 90° of shoulder abduction on two separate visits. Video sequences of median nerve excursion, recorded by a physical therapist using ultrasound imaging, were quantified using computer software. The generalizability theory, encompassing a G-Study and a D-study, measured the dependability coefficient (Φ) along with standard error of measurement (SEM) accuracy and allowed various testing protocols to be proposed. The highest reliability (Φ = 0.84) and lowest minimal measurement error (SEM = 0.58 mm) of the longitudinal median nerve excursion were reached during the ULNT-slider performed with 45° of shoulder abduction and when measures obtained from three different image sequences recorded during a single visit were averaged. It is recommended that longitudinal median nerve excursion measures computed from three separate image sequences recorded during a single visit be averaged in clinical practice. Ideally, adding a second visit (six image sequences) is also suggested in research protocols.

  20. The inverse hazard law: blood pressure, sexual harassment, racial discrimination, workplace abuse and occupational exposures in US low-income black, white and Latino workers.

    Science.gov (United States)

    Krieger, Nancy; Chen, Jarvis T; Waterman, Pamela D; Hartman, Cathy; Stoddard, Anne M; Quinn, Margaret M; Sorensen, Glorian; Barbeau, Elizabeth M

    2008-12-01

    Research on societal determinants of health suggests the existence of an "inverse hazard law," which we define as: "The accumulation of health hazards tends to vary inversely with the power and resources of the populations affected." Yet, little empirical research has systematically investigated this topic, including in relation to workplace exposures. We accordingly designed the United for Health study (Greater Boston Area, Massachusetts, 2003-2004) to investigate the joint distribution and health implications of workplace occupational hazards (dust, fumes, chemical, noise, ergonomic strain) and social hazards (racial discrimination, sexual harassment, workplace abuse). Focusing on blood pressure as our health outcome, we found that among the 1202 low-income multi-racial/ethnic working class participants in our cohort - of whom 40% lived below the US poverty line - 79% reported exposure to at least one social hazard and 82% to at least one high-exposure occupational hazard. Only sexual harassment, the least common social hazard, was associated with elevated systolic blood pressure (SBP) among the women workers. By contrast, no statistically significant associations were detectable between the other additional highly prevalent social and occupational hazards and SBP; we did, however, find suggestive evidence of an association between SBP and response to unfair treatment, implying that in a context of high exposure, differential susceptibility to the exposure matters. These results interestingly contrast to our prior findings for this same cohort, in which we found associations between self-reported experiences of racial discrimination and two other health outcomes: psychological distress and cigarette smoking. Likely explanations for these contrasting findings include: (a) the differential etiologic periods and pathways involving somatic health, mental health, and health behaviors, and (b) the high prevalence of adverse exposures, limiting the ability to detect

  1. Racial differences in long-term adherence to oral antidiabetic drug therapy: a longitudinal cohort study

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    Meigs James B

    2009-02-01

    Full Text Available Abstract Background Adherence to oral antidiabetic medications is often suboptimal. Adherence differences may contribute to health disparities for black diabetes patients, including higher microvascular event rates, greater complication-related disability, and earlier mortality. Methods In this longitudinal retrospective cohort study, we used 10 years of patient-level claims and electronic medical record data (1/1/1992–12/31/2001 to assess differences in short- and long-term adherence to oral antidiabetic medication among 1906 newly diagnosed adults with diabetes (26% black, 74% white in a managed care setting in which all members have prescription drug coverage. Four main outcome measures included: (1 time from diabetes diagnosis until first prescription of oral antidiabetic medication; (2 primary adherence (time from first prescription to prescription fill; (3 time until discontinuation of oral antidiabetic medication from first prescription; and (4 long-term adherence (amount dispensed versus amount prescribed over a 24-month follow-up from first oral antidiabetic medication prescription. Results Black patients were as likely as whites to initiate oral therapy and fill their first prescription, but experienced higher rates of medication discontinuation (HR: 1.8, 95% CI: 1.2, 2.7 and were less adherent over time. These black-white differences increased over the first six months of therapy but stabilized thereafter for patients who initiated on sulfonylureas. Significant black-white differences in adherence levels were constant throughout follow-up for patients initiated on metformin therapy. Conclusion Racial differences in adherence to oral antidiabetic drug therapy persist even with equal access to medication. Early and continued emphasis on adherence from initiation of therapy may reduce persistent racial differences in medication use and clinical outcomes.

  2. Effect of Health Comparisons on Functional Health and Depressive Symptoms - Results of a Population-Based Longitudinal Study of Older Adults in Germany.

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    André Hajek

    Full Text Available To investigate the effect of health comparisons on functional health and depressive symptoms in a longitudinal approach. Gender differences were examined.The German Ageing Survey (DEAS is a nationwide, representative longitudinal study of community dwelling individuals living in Germany aged 40 and older. The surveys in 2008 and 2011 were used, with n = 3,983 respondents taking part in both waves. Health comparisons were quantified by the question "How would you rate your health compared with other people your age" (Much better; somewhat better; the same; somewhat worse, much worse. Functional health was assessed by the subscale "physical functioning" of the 36-Item Short Form Health Survey (SF-36 and depressive symptoms were measured by the Center for Epidemiologic Studies Depression Scale (CES-D.Adjusting for sociodemographic factors, self-assessed health, social network, self-efficacy and optimism, and morbidity, fixed effects regressions revealed that functional health decreased significantly and considerably with negative health comparisons in the total sample (transitions from 'the same' to 'much worse': β = -11.8, predominantly in men. The effects of negative health comparisons (transitions from 'the same' to 'much worse': β = 4.8 on depressive symptoms were comparable (in terms of significance to the effects on functional health, with stronger effects in women. Positive comparisons did not affect functional health and depressive symptoms.Our findings underline the relevance of negative health comparisons on functional health (men and depressive symptoms (women. Comparison effects are asymmetric and mostly upwards.

  3. Fractal dimension and lacunarity analysis of mammographic patterns in assessing breast cancer risk related to HRT treated population: a longitudinal and cross-sectional study

    Science.gov (United States)

    Karemore, Gopal; Nielsen, Mads

    2009-02-01

    Structural texture measures are used to address the aspect of breast cancer risk assessment in screening mammograms. The current study investigates whether texture properties characterized by local Fractal Dimension (FD) and Lacunarity contribute to asses breast cancer risk. FD represents the complexity while the Lacunarity characterize the gappiness of a fractal. Our cross-sectional case-control study includes mammograms of 50 patients diagnosed with breast cancer in the subsequent 2-4 years and 50 matched controls. The longitudinal double blind placebo controlled HRT study includes 39 placebo and 36 HRT treated volunteers for two years. ROIs with same dimension (250*150 pixels) were created behind the nipple region on these radiographs. Box counting method was used to calculate the fractal dimension (FD) and the Lacunarity. Paired t-test and Pearson correlation coefficient were calculated. It was found that there were no differences between cancer and control group for FD (P=0.8) and Lacunarity (P=0.8) in crosssectional study whereas earlier published heterogeneity examination of radiographs (BC-HER) breast cancer risk score separated groups (p=0.002). In the longitudinal study, FD decreased significantly (Pbreast cancer risk, nor show good sensitivity to HRT.

  4. ¿POR QUÉ AUMENTA LA POBLACIÓN PENAL EN CHILE?: UN ESTUDIO CRIMINOLÓGICO LONGITUDINAL ¿Why is criminal population increasing in Chile?: a longitudinal criminology study

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    Sebastián Salinero Echeverría

    2012-01-01

    Full Text Available En este trabajo se analizan los factores y las respectivas causas del incremento de la población carcelaria en Chile entre el período 2000-2009. Se consigna que los factores que producirían la inflación penitenciaria son atribuibles al mayor ingreso de personas al sistema penal; al mayor tiempo de privación de libertad de los penados, y a la falta de mecanismos reales de descompresión carcelaria. A su vez, se analizan las causas que probablemente originarían estos factores, tales como la Reforma Procesal Penal y todo lo que ella introdujo desde la perspectiva de un nuevo sistema de administración de justicia penal; el punitivismo penal, con leyes que favorecerían la prisionización, y un marcado reduccionismo en los denominados beneficios legales alternativos a la prisión.In this paper the author analyzes the factors and causes of the increase in prison population in Chile between 2000 and 2009. It is stated that the factors that cause a rise in prison population are attributable to an increased inflow of people into the criminal system, to a longer incarceration of prisoners, and, to a lack of real mechanisms of prison reduction. In turn, the causes that are likely to originate these factors are analyzed, such as the Criminal Procedure Reform and everything it brought from the perspective of a new system of criminal justice, the punitive criminal justice that favor incarceration, and a marked reduction in legal benefits known as alternatives to prison.

  5. The longitudinal relationship of changes of adiposity to changes in pulmonary function and risk of asthma in a general adult population

    DEFF Research Database (Denmark)

    Fenger, Runa Vavia; Gonzalez-Quintela, Arturo; Vidal, Carmen

    2014-01-01

    changes in weight, body mass index, waist circumference, and fat percentage (bio-impedance) were analyzed with respect to changes of FEV1 and FVC (spirometry), and incidence of asthma and wheezing (questionnaire). Gender, atopy (serum specific IgE-positivity to inhalant allergens) and adipose tissue mass......BACKGROUND: Adiposity has been linked to both higher risk of asthma and reduced lung function. The effects of adiposity on asthma may depend on both atopic status and gender, while the relationship is less clear with respect to lung function. This study aimed to explore longitudinal weight changes...... not modify these associations. There were no statistically significant associations between changes in adiposity measures and risk of incident asthma or wheeze. CONCLUSIONS: Over a five-year period, increasing adiposity was associated with decreasing lung function, whereas decreasing adiposity was associated...

  6. Effects of aging on the function of the urinary system: longitudinal changes with age in selected urine parameters in a hospitalized population of older adults

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    Chmielewski Piotr

    2016-09-01

    Full Text Available Although normal aging does not have a pernicious effect on the homeostasis of fluids, renal reserve in elderly people can be depleted. The purpose of the present study was to assess the relationship between longitudinal changes with age in basic urine parameters (specific gravity and pH in older men and women, depending on their body height and relative body weight. Longitudinal data on these two quantitative traits of the urine were available for 142 physically healthy individuals, including 68 men and 74 women. All subjects were 45 years of age at the beginning and 70 at the end of the period under investigation. All measurements were taken in accordance with internationally accepted requirements. Specific gravity was assessed using a hydrometer, and pH was measured using a pH meter. ANOVA, t-test, and regression analysis were performed. No significant sex differences in specific gravity or urine pH were observed. In both sexes, urine specific gravity decreased with age according to exponential model of regression. In men, there was a gradual increase in the pH of the urine until age 65, and the best fitting regression model was polynomial. In women, on the other hand, there was an exiguous decrease in urine pH throughout the period under study, and the best fitting regression model proved to be exponential. As the process of renal aging commences relatively early in ontogeny and manifests itself in many structural and functional changes, urinalysis and other more sophisticated methods of diagnosis of renal diseases are essential for proper assessment of health status of adults and older individuals. The rate of age-related changes in the analyzed traits of the urine was commensurate in both sexes, thereby revealing no evidence of significant sex differences in terms of renal aging in the period between 45 and 70 years of age.

  7. From epidemiology to daily life : Linking daily life stress reactivity to persistence of psychotic experiences in a longitudinal general population study

    NARCIS (Netherlands)

    Collip, Dina; Wigman, Johanna T. W.; Myin-Germeys, Inez; Jacobs, Nele; Derom, Catherine; Thiery, Evert; Wichers, Marieke; van Os, Jim

    2013-01-01

    Subclinical psychotic experiences at the level of the general population are common, forming an extended psychosis phenotype with clinical psychosis. Persistence of subclinical experiences is associated with transition to later mental disorder. Increased daily life stress reactivity is considered an

  8. Black&White [Pròleg

    OpenAIRE

    Sánchez Durá, Nicolás

    2014-01-01

    Este libro analiza los distintos usos de la fotografía en el periodo clásico de la Antropología en el que se constituyó la autoridad etnográfica. Usos que no solo refieren al trabajo de campo de los etnógrafos, sino también a la posterior circulación de las imágenes fotográficas en publicaciones, museos y archivos. Centrado en el arranque de la tradición africanista francesa (M. Griaule, M. Leiris…), el autor no olvida en su análisis comparativo a los pioneros del medio académico anglo-sajón ...

  9. T allele at site 6007 of bone morphogenetic protein-4 gene increases genetic susceptibility to ossification of the posterior longitudinal ligament in male Chinese Han population

    Institute of Scientific and Technical Information of China (English)

    MENG Xiang-long; WANG Hao; YANG Hui; HAI Yong; TIAN Bao-peng; LIN Xin

    2010-01-01

    Background Several candidate genes of ossification of the posterior longitudinal ligament (OPLL) susceptibility have been identified, but their polymorphisms account for only a small percent of the total variance. Bone morphogenetic protein-4 (BMP4) is a potent ectopic ossification inducing factor. BMP4 protein and mRNA are present in cells from OPLL patients, but not non-OPLL controls. A single nucleotide polymorphism of 6007C>T(rs17563) of BMP4 has been reported to affect bone density in postmenopausal women. Thus, BMP4 may function in OPLL development. Appropriately, the relationship between BMP4 polymorphisms and OPLL was investigated.Methods A case-control association study investigated the genetic etiology in 179 OPLL patients and 298 non-OPLL controls. Extent of OPLL was analyzed by radiologic examinations. Whether single nucleotide polymorphism (SNP) of -5826G>A(rs1957860) 5′ of the transcription start site and 6007C>T(rs17563) in exon 4 of the BMP4 gene were statistically associated with genetic susceptibility to OPLL in Chinese Han subjects was assessed.Results A significant statistical difference in genotype of 6007C>T polymorphism between male OPLL patients and male controls was evident, and the frequency of "TT" genotype in male OPLL patients was significantly higher than in male controls (P=0.039). The frequency of the "T" allele was also significantly higher in male OPLL subjects than in male controls (P=0.014, 0R=1.57). A significant difference was also observed between the 6007C>T polymorphism and the number of ossified cervical vertebrae in OPLL patients, while no statistical difference was apparent between the -5826G>A polymorphism and OPLL occurrence.Conclusions The T allele in the 6007C>T polymorphism may be a risk factor for male Han Chinese with ossification of the posterior longitudinal ligament in the cervical spine. Chinese Han male patients with CT and TT 6007C>T genotypes have a genetic susceptibility to OPLL and more extensive OPLL in

  10. 不同水平肌醇对黑白花奶牛乳成分的影响%The effect of different levels of inoses on milk composition of black-white dairy cows

    Institute of Scientific and Technical Information of China (English)

    孙超; 高景慧; 张文晋

    2001-01-01

    Forty black-white dairy cows were used as experimental animals.T hey were divided into three experimental groups and a contrast group.The experi mental groups were added respectively 0.1,\\{0.2\\},0.3 g/(one*d) inoses to study the effect of different levels of inoses on milk yield,food consumption and mil k composition.The results showed:the increasing degrees of milk yield,food consu mption and milkfat,milkprotein,milksuger,nonfat solidity,total solidity in the s econd experimental group were the biggest,3.76 kg/d,3.36 kg/d,0.90 g/kg,0.91g/ k g,0.73 g/kg/d,1.04 g/ kg,1.00 g/ kg,respectively.It proved that adding 0.2 g/(on e*d) inoses in the diets for dairy cows was best for promoting milk yield,food consumption and milk composition.%以40头黑白花奶牛为实验动物,随机分成3个试验组和1个对照组,各试验组分别添加0.1,0.2,0.3 g/(头*d)肌醇,研究其对奶牛产奶量、采食量以及乳成份的影响。结果表明:试验Ⅱ组中产奶量、采食量、乳脂、乳蛋白、乳糖、无脂固形物和总固形物的增加量最大,分别为3.76 kg/d,3.36 kg/d,0.90 g/kg,0.91 g/kg,\\{0.73 g/kg\\},1.04 g/kg和1.00 g/ kg。证明在奶牛日粮中添加0.2 g/(头*d)肌醇对提高产奶量,采食量以及乳成份最好。

  11. A population-based longitudinal study of recent stressful life events as risk factors for suicidal behavior in major depressive disorder.

    Science.gov (United States)

    Wang, Yunqiao; Sareen, Jitender; Afifi, Tracie O; Bolton, Shay-Lee; Johnson, Edward A; Bolton, James M

    2015-01-01

    The purpose of this study is to investigate whether the type and number of stressful life events (SLEs) will be associated with suicidal behavior in a 3-year follow-up period in persons with major depressive disorder (MDD). Data came from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a nationally representative longitudinal survey of mental health in non-institutionalized adults in the United States. The survey consisted of two waves: Wave 1 (2001--2002) and Wave 2 (2004-2005), n = 34,653. Twelve past-year SLEs were assessed at baseline. These SLEs were categorized into the following groups based on previous research: Loss or victimization; Relationship, friendship, or interpersonal stress; Financial stress; and Legal problems. Only respondents with MDD at Wave 1 were included (n = 6,004). Several SLEs were strongly associated with suicide attempts, among which, "serious problems with neighbor, friend, or relative" (adjusted odds ratio [AOR] = 2.21; 95% confidence interval [95% CI]: 1.41, 3.45) and "major financial crisis, bankruptcy, or unable to pay bills" (AOR = 2.31; 95% CI: 1.45, 3.66) were the most robust predictors of suicide attempts even after adjusting for sociodemographic variables and any anxiety, substance use, or personality disorder. People with MDD who had been exposed to certain SLEs are at elevated risk for future suicide attempts, even after accounting for the demographic factors and psychiatric comorbidity.

  12. Risk factors associated with trajectories of mothers' depressive symptoms across the early parenting period: an Australian population-based longitudinal study.

    Science.gov (United States)

    Giallo, Rebecca; Cooklin, Amanda; Nicholson, Jan M

    2014-04-01

    Approximately 14 % of women experience depressive symptoms in the first postnatal year. Few studies have examined the persistence of symptoms beyond this time. This study aims to (a) assess the course of women's depressive symptoms from the first postnatal year to when their children were aged 6-7 years, (b) identify distinct groups of women defined by their symptom trajectories over time, and (c) identify antenatal and early postnatal risk factors associated with persistent symptoms. Data from 4,879 women participating in the Longitudinal Study of Australian Children were analysed using latent growth modelling and logistic regression to identify risk factors associated with class membership. For the overall sample, depressive symptoms were highest during the first postnatal year and then gradually decreased over 6-7 years. Two distinct classes were identified with the majority of women (84 %) reporting minimal symptoms over time, and 16 % experiencing persistently high symptoms. Risk factors were younger maternal age, being from a non-English speaking background, not completing high school, having a past history of depression, antidepressant use during pregnancy, child development problems, lower parenting self-efficacy, poor relationship quality, and stressful life events. This research identifies risk factors that may predispose mothers to enduring depressive symptoms, offering opportunities for early identification and targeted early intervention.

  13. Isolated transverse process fractures of the subaxial cervical spine: a clinically insignificant injury or not?: a prospective, longitudinal analysis in a consecutive high-energy blunt trauma population.

    NARCIS (Netherlands)

    Schotanus, M.; Middendorp, J.J. van; Hosman, A.J.F.

    2010-01-01

    STUDY DESIGN: Prospective single cohort study. OBJECTIVE: To analyze the incidence, associated injuries, treatment outcomes and associated adverse events of isolated transverse process fractures (TPFs) of the subaxial cervical spine in a high-energy blunt trauma population. SUMMARY OF BACKGROUND DAT

  14. Classification-based data mining for identification of risk patterns associated with hypertension in Middle Eastern population: A 12-year longitudinal study.

    Science.gov (United States)

    Ramezankhani, Azra; Kabir, Ali; Pournik, Omid; Azizi, Fereidoun; Hadaegh, Farzad

    2016-08-01

    Hypertension is a critical public health concern worldwide. Identification of risk factors using traditional multivariable models has been a field of active research. The present study was undertaken to identify risk patterns associated with hypertension incidence using data mining methods in a cohort of Iranian adult population.Data on 6205 participants (44% men) age > 20 years, free from hypertension at baseline with no history of cardiovascular disease, were used to develop a series of prediction models by 3 types of decision tree (DT) algorithms. The performances of all classifiers were evaluated on the testing data set.The Quick Unbiased Efficient Statistical Tree algorithm among men and women and Classification and Regression Tree among the total population had the best performance. The C-statistic and sensitivity for the prediction models were (0.70 and 71%) in men, (0.79 and 71%) in women, and (0.78 and 72%) in total population, respectively. In DT models, systolic blood pressure (SBP), diastolic blood pressure, age, and waist circumference significantly contributed to the risk of incident hypertension in both genders and total population, wrist circumference and 2-h postchallenge plasma glucose among women and fasting plasma glucose among men. In men, the highest hypertension risk was seen in those with SBP > 115 mm Hg and age > 30 years. In women those with SBP > 114 mm Hg and age > 33 years had the highest risk for hypertension. For the total population, higher risk was observed in those with SBP > 114 mm Hg and age > 38 years.Our study emphasizes the utility of DTs for prediction of hypertension and exploring interaction between predictors. DT models used the easily available variables to identify homogeneous subgroups with different risk pattern for the hypertension.

  15. Long-term Effects of Antihypertensive Drug Use and New-onset Osteoporotic Fracture in Elderly Patients: A Population-based Longitudinal Cohort Study

    Science.gov (United States)

    Chen, Hung-Yi; Ma, Kai-Yan; Hsieh, Pei-Ling; Liou, Yi-Sheng; Jong, Gwo-Ping

    2016-01-01

    Background: Antihypertensive drugs have been linked to new-onset osteoporotic fracture (NOF), and different classes of antihypertensive drugs may alter the risk for the development of NOF; however, the classic effect of different antihypertensive drugs on the development of NOF in the elderly has not been well studied during long-term follow-up. Methods: In this study, we investigated the association between different classic antihypertensives and the development of NOF in the elderly. This was a longitudinal cohort study performed using data from claim forms submitted to the Taiwan Bureau of National Health Insurance in Central Taiwan, China including case patients with NOF aged 65–80 years from January 2002 to December 2012 and non-NOF controls. Prescriptions for antihypertensives before the index date were retrieved from a prescription database. We estimated the hazard ratios (HRs) of NOF associated with antihypertensive use. Non-NOF controls served as the reference group. Results: A total of 128 patients with NOF were identified from among 1144 patients with hypertension during the study period. The risk of NOF after adjusting age, sex, comorbidities, and concurrent medications was higher among the users of angiotensin-converting enzyme (ACE) inhibitors (HR, 1.64; 95% confidence interval [CI], 1.01–2.66) than among nonusers. Patients who took calcium channel blockers (CCBs) (HR, 0.70; 95% CI, 0.49–0.99) were at a lower risk of developing NOF than nonusers. Loop diuretics, thiazide diuretics, angiotensin receptor blocker, beta-blocker, and alpha-blocker were not associated with the risk of NOF. Conclusions: Elderly with hypertension who take CCBs are at a lower risk of NOF and that the use of ACE inhibitors was associated with a significantly increased risk of developing NOF during the 11-year follow-up. PMID:27958221

  16. Depressive Symptoms and Risk of New Cardiovascular Events or Death in Patients with Myocardial Infarction: A Population-Based Longitudinal Study Examining Health Behaviors and Health Care Interventions

    DEFF Research Database (Denmark)

    Larsen, Karen Kjær; Christensen, Bo; Søndergaard, Jens

    2013-01-01

    preventive factors. We further explored whether we could identify subgroups of patients with a particularly high relative risk of adverse outcomes. Methods and Results: We conducted a prospective population-based cohort study of 897 patients discharged with firsttime MI between 1 January 2009 and 31 December......-years of follow-up. Event-free survival was evaluated using Cox regression analysis. Compared to the 730 patients without depressive symptoms (HADS-D,8), the 167 patients with depressive symptoms (HADS-D$8) had age- and sex-adjusted hazard ratios [HR] (95% confidence interval [CI]) of 1.53 (95% CI, 1...

  17. Applied longitudinal analysis

    CERN Document Server

    Fitzmaurice, Garrett M; Ware, James H

    2012-01-01

    Praise for the First Edition "". . . [this book] should be on the shelf of everyone interested in . . . longitudinal data analysis.""-Journal of the American Statistical Association   Features newly developed topics and applications of the analysis of longitudinal data Applied Longitudinal Analysis, Second Edition presents modern methods for analyzing data from longitudinal studies and now features the latest state-of-the-art techniques. The book emphasizes practical, rather than theoretical, aspects of methods for the analysis of diverse types of lo

  18. A longitudinal evaluation of the Center for Epidemiologic Studies-Depression scale (CES-D in a Rheumatoid Arthritis Population using Rasch Analysis

    Directory of Open Access Journals (Sweden)

    Tennant Alan

    2007-07-01

    Full Text Available Abstract Background The aim of this study was to test the internal validity of the total Center for Epidemiologic Studies-Depression (CES-D scale using Rasch analysis in a rheumatoid arthritis (RA population. Methods CES-D was administered to 157 patients with RA over three time points within a 12 month period. Rasch analysis was applied using RUMM2020 software to assess the overall fit of the model, the response scale used, individual item fit, differential item functioning (DIF and person separation. Results Pooled data across three time points was shown to fit the Rasch model with removal of seven items from the original 20-item CES-D scale. It was necessary to rescore the response format from four to three categories in order to improve the scale's fit. Two items demonstrated some DIF for age and gender but were retained within the 13-item CES-D scale. A new cut point for depression score of 9 was found to correspond to the original cut point score of 16 in the full CES-D scale. Conclusion This Rasch analysis of the CES-D in a longstanding RA cohort resulted in the construction of a modified 13-item scale with good internal validity. Further validation of the modified scale is recommended particularly in relation to the new cut point for depression.

  19. A population-based longitudinal study of suicide risk in male schizophrenia patients: Proximity to hospital discharge and the moderating effect of premorbid IQ.

    Science.gov (United States)

    Weiser, Mark; Kapara, Ori; Werbeloff, Nomi; Goldberg, Shira; Fenchel, Daphna; Reichenberg, Abraham; Yoffe, Rinat; Ginat, Keren; Fruchter, Eyal; Davidson, Michael

    2015-12-01

    Suicide is a major cause of death in schizophrenia. Identifying factors which increase the risk of suicide among schizophrenia patients might help focus prevention efforts. This study examined risk of suicide in male schizophrenia patients using population-based data, examining the timing of suicide in relation to the last hospital discharge, and the effect of premorbid IQ on risk of suicide. Data on 930,000 male adolescents from the Israeli military draft board were linked with data from the Israeli Psychiatric Hospitalization Case Registry and vital statistics from the Israeli Ministry of Health. The relationship between premorbid IQ and risk for suicide was examined among 2881 males hospitalized with schizophrenia and compared to a control group of 566,726 males from the same cohort, who were not hospitalized for a psychiatric disorder, using survival analysis methods. Over a mean follow-up period of 9.9 years (SD=5.8, range: 0-22 years), 77/3806 males with schizophrenia died by suicide (a suicide rate of 204.4 per 100,000 person-years). Approximately 48% of the suicides occurred within a year of discharge from the last hospital admission for schizophrenia. Risk of suicide was higher in male schizophrenia patients with high premorbid IQ (HR=4.45, 95% CI=1.37-14.43) compared to those with normal premorbid IQ. These data indicate that male schizophrenia patients with high premorbid IQ are at particularly high risk of suicide, and the time of peak risk is during the first year after the last hospitalization discharge.

  20. Increased risk of ischemic heart disease in young patients with newly diagnosed ankylosing spondylitis--a population-based longitudinal follow-up study.

    Directory of Open Access Journals (Sweden)

    Ya-Ping Huang

    Full Text Available BACKGROUND: Prospective data is sparse on the association between ischemic heart disease (IHD and ankylosing spondylitis (AS in the young. The purpose of this population-based, age- and sex-matched follow-up study was to investigate the risk of IHD in young patients with newly diagnosed AS. METHODS: A total of 4794 persons aged 18 to 45 years with at least two ambulatory visits in 2001 with the principal diagnosis of AS were enrolled in the AS group. The non-AS group consisted of 23970 age- and sex-matched, randomly sampled subjects without AS. The three-year IHD-free survival rate and cumulative incidence of IHD were calculated using the Kaplan-Meier method. The Cox proportional hazards regression model was used to estimate the hazard ratio of IHD after controlling for demographic and cardiovascular co-morbidities. RESULTS: During follow-up, 70 patients in the AS group and 253 subjects in the non-AS group developed IHD. The cumulative incidence rate of IHD over time was higher in the AS group than the non-AS group. The crude hazard ratio of IHD for the AS group was 1.47 (95% CI, 1.13 to 1.92; p = 0.0043 and the adjusted hazard ratio after controlling for demographic characteristics and comorbid medical disorders was 1.47 (95% CI, 1.13 to 1.92; p = 0.0045. CONCLUSIONS: This study showed an increased risk of developing IHD in young patients with newly diagnosed AS.

  1. C-reactive protein, high-molecular-weight adiponectin and development of metabolic syndrome in the Japanese general population: a longitudinal cohort study.

    Directory of Open Access Journals (Sweden)

    Yoshifumi Saisho

    Full Text Available AIMS: To clarify predictive values of C-reactive protein (CRP and high-molecular-weight (HMW adiponectin for development of metabolic syndrome. RESEARCH DESIGN AND METHODS: We conducted a prospective cohort study of Japanese workers who had participated in an annual health checkup in 2007 and 2011. A total of 750 subjects (558 men and 192 women, age 46±8 years who had not met the criteria of metabolic syndrome and whose CRP and HMW-adiponectin levels had been measured in 2007 were enrolled in this study. Associations between CRP, HMW-adiponectin and development of metabolic syndrome after 4 years were assessed by logistic regression analysis and their predictive values were compared by receiver operating characteristic analysis. RESULTS: Among 750 subjects, 61 (8.1% developed metabolic syndrome defined by modified National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III criteria and 53 (7.1% developed metabolic syndrome defined by Japan Society for the Study of Obesity (JASSO in 2011. Although CRP and HMW-adiponectin were both significantly correlated with development of metabolic syndrome, multivariate logistic regression analysis revealed that HMW-adiponectin but not CRP was associated with metabolic syndrome independently of BMI or waist circumference. Adding these biomarkers to BMI or waist circumference did not improve the predictive value for metabolic syndrome. CONCLUSION: Our findings indicate that the traditional markers of adiposity such as BMI or waist circumference remain superior markers for predicting metabolic syndrome compared to CRP, HMW-adiponectin, or the combination of both among the Japanese population.

  2. A synthetic Longitudinal Study dataset for England and Wales.

    Science.gov (United States)

    Dennett, Adam; Norman, Paul; Shelton, Nicola; Stuchbury, Rachel

    2016-12-01

    This article describes the new synthetic England and Wales Longitudinal Study 'spine' dataset designed for teaching and experimentation purposes. In the United Kingdom, there exist three Census-based longitudinal micro-datasets, known collectively as the Longitudinal Studies. The England and Wales Longitudinal Study (LS) is a 1% sample of the population of England and Wales (around 500,000 individuals), linking individual person records from the 1971 to 2011 Censuses. The synthetic data presented contains a similar number of individuals to the original data and accurate longitudinal transitions between 2001 and 2011 for key demographic variables, but unlike the original data, is open access.

  3. Intake of Vitamin and Mineral Supplements and Longitudinal Association with HbA1c Levels in the General Non-Diabetic Population--Results from the MONICA/KORA S3/F3 Study.

    Directory of Open Access Journals (Sweden)

    Sigrid Schwab

    Full Text Available Lower levels of hemoglobin A1c (HbA1c are associated with a decreased risk of cardiovascular complications in diabetic and non-diabetic individuals. The aim of the study was to longitudinally investigate the association between the use of 11 vitamins and minerals (vitamins E, C, D, B1, folic acid, carotenoids, calcium, magnesium, zinc, iron, and selenium and change in HbA1c levels over 10 years in non-diabetic individuals drawn from the general population.Baseline data were available from 4447 subjects included in the population-based "Monitoring of Trends and Determinants in Cardiovascular Diseases" (MONICA Augsburg S3 survey (1994/95. Follow-up data were derived from 2774 participants in the follow-up survey named "Cooperative Health Research in the Region of Augsburg" (KORA F3 (2004/05. Vitamin/mineral intake from supplements and medications was assessed in a personal interview, where participants were asked to bring product packages of preparations that had been ingested during the last 7 days prior to the examination. Associations between regular vitamin/mineral intake amounts and HbA1c levels measured at baseline and follow-up were investigated using generalized estimating equation models. For carotenoids, analyses were stratified by smoking status.None of the investigated nutrients except for carotenoids was significantly associated with changes in HbA1c levels after 10 years. Regular intake of carotenoids from supplements and medications in amounts > 6.8 mg/d (upper tertile was associated with an absolute -0.26% (95% CI: -0.43 to -0.08 lower increase in HbA1c levels compared with no intake of carotenoids. An inverse association was observed in those who never smoked but not in (former smokers.Larger prospective and intervention studies in non-diabetic/non-smoking individuals are needed to confirm the results and to assess whether the observed associations between carotenoid intake and change in HbA1c levels are causal. If our results are

  4. Longitudinal impedance of RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brennan, J. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    The longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. For the blue RHIC ring Im(Z/n) = 1.5±0.2Ω. For the yellow ring Im(Z/n) = 5.4±1Ω.

  5. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between...

  6. Longitudinal categorical data analysis

    CERN Document Server

    Sutradhar, Brajendra C

    2014-01-01

    This is the first book in longitudinal categorical data analysis with parametric correlation models developed based on dynamic relationships among repeated categorical responses. This book is a natural generalization of the longitudinal binary data analysis to the multinomial data setup with more than two categories. Thus, unlike the existing books on cross-sectional categorical data analysis using log linear models, this book uses multinomial probability models both in cross-sectional and longitudinal setups. A theoretical foundation is provided for the analysis of univariate multinomial responses, by developing models systematically for the cases with no covariates as well as categorical covariates, both in cross-sectional and longitudinal setups. In the longitudinal setup, both stationary and non-stationary covariates are considered. These models have also been extended to the bivariate multinomial setup along with suitable covariates. For the inferences, the book uses the generalized quasi-likelihood as w...

  7. Effects of Longitudinal Photons

    CERN Document Server

    Friberg, C; Friberg, Christer; Sjöstrand, Torbjörn

    2000-01-01

    The description of longitudinal photons is far from trivial, and their phenomenological importance is largely unknown. While the cross section for direct interactions is calculable, an even more important contribution could come from resolved states. In the development of our model for the interactions of (real and) virtual photons, we have modeled resolved longitudinal effects by simple multiplicative factors on the resolved transverse-photon contributions. Recently, a first set of parton distributions for longitudinal virtual photons has been presented by Ch\\'yla. We therefore compare their impact on some representative distributions, relative to the simpler approaches.

  8. Longitudinal Magnification Drawing Mistake

    Science.gov (United States)

    Rabal, Héctor; Cap, Nelly; Trivi, Marcelo

    2004-01-01

    Lateral magnification in image formation by positive lenses, mirrors, and dioptrics is usually appropriately developed in most optics textbooks.1-9 However, the image of a three-dimensional object occupies a three-dimensional region of space. The optical system affects both the transverse and the longitudinal dimensions of the object and, in general, does it in different ways. The magnification in the direction of the optical axis (the longitudinal magnification) is seldom treated. In several texts, the concept of longitudinal magnification is not even considered. Symmetrical objects (such as arrows) are used and their images appear laterally inverted. It is not shown how a longitudinally nonsymmetric object is imaged. One of the few books where this subject is well treated is in the textbook by Hecht.10 We have repeatedly verified in our classes that there is some confusion related to this subject. Students tend to believe that the image is longitudinally symmetric with respect to the lens optic center. Some prestigious texts commit the same mistake. In addition, a very nice optics book,11 a catalogue of optical hardware,12 a worldwide scientific magazine,13 a paper in an optics journal,14 and a Spanish encyclopedia,15 for example, have also been found to contain this error in drawing the image of a three-dimensional object formed by a positive lens. In this paper we suggest that the teaching of longitudinal magnification should be done with some care and we include a figure showing a properly drawn image.

  9. Elaboração e validação de intervalos de referência longitudinais de peso fetal com uma amostra da população brasileira Elaboration and validation of longitudinal reference intervals of fetal weight with a sample of the Brazilian population

    Directory of Open Access Journals (Sweden)

    Érica Luciana de Paula Furlan

    2012-10-01

    Full Text Available OBJETIVOS: Elaborar modelos de predição de peso fetal e de percentis longitudinais de peso fetal estimado (PFE com uma amostra da população brasileira. MÉTODOS: Estudo observacional prospectivo. Dois grupos de gestantes foram recrutados: Grupo EPF (estimativa de peso fetal: pacientes para elaboração (EPF-El e validação (EPF-Val de um modelo de predição de peso fetal; Grupo IRL (intervalos de referência longitudinais: gestantes para elaboração (IRL-El e validação (IRL-Val de intervalos de referência longitudinais de PFE. Regressão polinomial foi utilizada com os dados do subgrupo EPF-El para gerar o modelo de predição de peso fetal. O desempenho deste modelo foi comparado com os de outros disponíveis na literatura. Modelos lineares mistos foram usados para elaboração de intervalos longitudinais de PFE com os dados do subgrupo IRL-El. Os dados do subgrupo IRL-Val foram usados para validação destes intervalos. RESULTADOS: Quatrocentos e cinqüenta e oito pacientes compuseram o Grupo EPF (EPF-El: 367; EPF-Val: 91 e 315 o Grupo IRL (IRL-El: 265; IRL-Val: 50. A fórmula para cálculo do PFE foi: PFE=-8,277+2,146xDBPxCAxCF-2,449xCFxDBP². Os desempenhos de outras fórmulas para estimativa de peso fetal em nossa amostra foram significativamente piores do que os do modelo gerado neste estudo. Equações para predição de percentis condicionais de PFE foram derivadas das avaliações longitudinais do subgrupo IRL-El e validadas com os dados do subgrupo IRL-Val. CONCLUSÕES: descrevemos um método para adaptação de intervalos de referência longitudinais de PFE, sendo este obtido por meio de fórmulas geradas em uma amostra da população brasileira.PURPOSES: To elaborate models for the estimation of fetal weight and longitudinal reference intervals of estimated fetal weight (EFW using a sample of the Brazilian population. METHODS: Prospective observational study. Two groups of patients were evaluated: Group EFW (estimation of

  10. Patterns of Multimorbidity in an Older Population of Persons with an Intellectual Disability: Results from the Intellectual Disability Supplement to the Irish Longitudinal Study on Aging (IDS-TILDA)

    Science.gov (United States)

    McCarron, Mary; Swinburne, Janet; Burke, Eilish; McGlinchey, Eimear; Carroll, Rachael; McCallion, Philip

    2013-01-01

    Multimorbidity (2 or more chronic conditions) is being widely studied in older populations and this study explores both the relevance of emerging conceptualizations and the extent to which multimorbidity is a feature of aging in persons with an intellectual disability. Methods: Data was generated from wave one of the intellectual disability…

  11. 2016 - Black & White - Rutland and Windsor (0.3m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This metadata record describes the acquisition and production of greyscale digital ground orthoimagery covering a portion of Vermont State. The...

  12. Theories about Black-White Interracial Marriage: A Clinical Perspective.

    Science.gov (United States)

    Davidson, Jeanette R.

    1992-01-01

    Directs attention to a number of theories about African-American-white interracial marriage found in the literature of the social sciences. Notes that theories suggest that couples who marry interracially generally have ulterior motives for doing so. Soundness of these theories is refuted, and suggestions are presented for clinicians working with…

  13. 2009 - Black & White - Essex (0.5m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VTORTHO_0_5M_PAN_2009 data includes panchromatic (black and white) orthophotography (orthophoto) at 1:5000 scale (0.5 meter cell resolution)....

  14. Understanding the Black-White School Discipline Gap

    Science.gov (United States)

    Kinsler, Josh

    2011-01-01

    At state and national levels, black students are more likely to be suspended from school, and conditional on misbehavior, receive stiffer penalties when compared with white students. Racial bias is often cited as a primary contributor to these gaps. Using infraction data from North Carolina, I investigate gaps in punishment within and across…

  15. Black-White Differences in Returns to Schooling

    Science.gov (United States)

    Welch, Finis

    1973-01-01

    An empirical attempt to identify some of the structural components of the observed rapid rise in the relative earnings of blacks in the United States between 1959 and 1966. Major components considered include quality of schooling, years of schooling, and weeks worked in a year. (Author/DN)

  16. 2013 - Black & White - most of Chittenden Co. (15 cm)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This metadata record describes the acquisition and production of the greyscale digital orthoimagery covering a portion of Chittenden County,...

  17. Black-white preterm birth disparity: a marker of inequality

    Science.gov (United States)

    Purpose. The racial disparity in preterrn birth (PTB) is a persistent feature of perinatal epidemiology, inconsistently modeled in the literature. Rather than include race as an explanatory variable, or employ race-stratified models, we sought to directly model the PTB disparity ...

  18. Towards a Philosophy of Science for Black - White Studies.

    Science.gov (United States)

    1984-08-20

    on White dislike for White skin -- evidenced by the popularity of sunbathing among Whites despite the risk of cancer . Each group assesses the other on...responsible trying to please incompetent hard-working childish loyal or unreasonable BOTTOMS innocent demanding manipulable antagnostic resistant or

  19. IQ Tests Are Not Culturally Biased for Blacks & Whites

    Science.gov (United States)

    Jensen, Arthur R.

    1976-01-01

    Concludes that these standardized tests of intelligence--the Peabody Picture Vocabulary, Raven's Progressive Matrices, Stanford-Binet, Wechsler Intelligence Scale for Children, Wonderlic Personnel Test, and most likely many other similar tests--show practically no evidence of differential culture bias for blacks and whites. (Author)

  20. Loading Conditions and Longitudinal Strength

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1995-01-01

    Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength.......Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength....

  1. A Longitudinal Density Monitor for the LHC

    CERN Document Server

    Jeff, Adam; Boccardi, Andrea

    At the Large Hadron Collider (LHC), the world’s largest and highest energy particle accelerator, ion bunches circulate in two counter-rotating beams and are brought into collision. Each bunch is confined within a bucket by the longitudinal focusing effect of the radio frequency (RF) cavities. The RF period is 2.5 ns, while the minimum bunch spacing is 25 ns. Thus, 9 out of every 10 buckets should be empty, as well as additional gaps to allow for the rise-time of injection and dump kickers. In practice, however, small numbers of particles can occupy these supposedly empty buckets, causing problems for machine protection and for the absolute calibration of the LHC’s luminosity. The Longitudinal Density Monitor (LDM) is a new monitor, designed to measure the longitudinal distribution of particles in the LHC with a sufficiently high dynamic range to quantify the relative particle population in the supposedly empty buckets. A non-interceptive measurement is made possible by the use of synchrotron radiation (SR...

  2. What Alumni Value from New Product Development Education: A Longitudinal Study

    Science.gov (United States)

    Cobb, Corie L.; Hey, Jonathan; Agogino, Alice M.; Beckman, Sara L.; Kim, Sohyeong

    2016-01-01

    We present a longitudinal study of what graduates take away from a cross-disciplinary graduate-level New Product Development (NPD) course at UC Berkeley over a 15-year period from 1996-2010. We designed and deployed a longitudinal survey and interviewed a segment of our NPD alumni population to better understand how well our course prepared these…

  3. Response rates and selection problems, with emphasis on mental health variables and DNA sampling, in large population-based, cross-sectional and longitudinal studies of adolescents in Norway

    Directory of Open Access Journals (Sweden)

    Lien Lars

    2010-10-01

    Full Text Available Abstract Background Selection bias is a threat to the internal validity of epidemiological studies. In light of a growing number of studies which aim to provide DNA, as well as a considerable number of invitees who declined to participate, we discuss response rates, predictors of lost to follow-up and failure to provide DNA, and the presence of possible selection bias, based on five samples of adolescents. Methods We included nearly 7,000 adolescents from two longitudinal studies of 18/19 year olds with two corresponding cross-sectional baseline studies at age 15/16 (10th graders, and one cross-sectional study of 13th graders (18/19 years old. DNA was sampled from the cheek mucosa of 18/19 year olds. Predictors of lost to follow-up and failure to provide DNA were studied by Poisson regression. Selection bias in the follow-up at age 18/19 was estimated through investigation of prevalence ratios (PRs between selected exposures (physical activity, smoking and outcome variables (general health, mental distress, externalizing problems measured at baseline. Results Out of 5,750 who participated at age 15/16, we lost 42% at follow-up at age 18/19. The percentage of participants who gave their consent to DNA provision was as high as the percentage that consented to a linkage of data with other health registers and surveys, approximately 90%. Significant predictors of lost to follow-up and failure to provide DNA samples in the present genetic epidemiological study were: male gender; non-western ethnicity; postal survey compared with school-based; low educational plans; low education and income of father; low perceived family economy; unmarried parents; poor self-reported health; externalized symptoms and smoking, with some differences in subgroups of ethnicity and gender. The association measures (PRs were quite similar among participants and all invitees, with some minor discrepancies in subgroups of non-western boys and girls. Conclusions Lost to

  4. Sensitivity Analysis of Mixed Models for Incomplete Longitudinal Data

    Science.gov (United States)

    Xu, Shu; Blozis, Shelley A.

    2011-01-01

    Mixed models are used for the analysis of data measured over time to study population-level change and individual differences in change characteristics. Linear and nonlinear functions may be used to describe a longitudinal response, individuals need not be observed at the same time points, and missing data, assumed to be missing at random (MAR),…

  5. Criminal Victimization and Crime Risk Perception: A Multilevel Longitudinal Study

    Science.gov (United States)

    Russo, Silvia; Roccato, Michele; Vieno, Alessio

    2013-01-01

    In a national sample of the Italian population, surveyed four times between October 2002 and January 2007 (N = 2,008), we performed a multilevel longitudinal study aimed at predicting the increase in crime risk perception as a function of three families of independent variables, respectively lying at the within individual level (direct…

  6. Impacto de la morbilidad, uso de recursos y costes en el mantenimiento de la remisión de la depresión mayor en España: estudio longitudinal de ámbito poblacional Impact of morbidity, resource use and costs on maintenance of remission of major depression in Spain: a longitudinal study in a population setting

    Directory of Open Access Journals (Sweden)

    Antoni Sicras-Mainar

    2010-01-01

    Full Text Available Objetivo: Determinar el impacto de la comorbilidad, el uso de recursos y los costes (sanitarios y en pérdidas de productividad laboral en el mantenimiento de la remisión de la depresión en un ámbito poblacional español. Métodos: Diseño observacional, prospectivo, multicéntrico, realizado con bases de datos poblacionales. Los criterios de inclusión fueron: edad >18 años, inicio del episodio depresivo entre enero de 2003 y marzo de 2007, prescripción de antidepresivos >60 días después de la primera prescripción y duración del seguimiento de 18 meses (estudio: 12 meses; continuación: 6 meses. Se consideraron 2 subgrupos: pacientes en remisión y sin remisión. Las principales mediciones fueron sociodemográficas, episodios, bandas de utilización de recursos, costes sanitarios (directos y en pérdidas de productividad (indirectos. Se realizó análisis de regresión logística y de análisis de la covarianza (ajuste Bonferroni. Resultados: Se reclutaron 4.572 sujetos. El 54,6% (intervalo de confianza del 95%: 53,2-56,0% se consideraron en remisión. Los pacientes en remisión mostraron menor edad (52,6 frente a 60,7 años, mayor proporción de mujeres (71,7% frente a 78,2%, más morbilidad general (6,2 frente a 7,7 episodios/año, menos bandas de utilización de recursos/año (2,7 frente a 3,0, menor incapacidad laboral (31,0 frente a 38,5 días y menor duración del tratamiento antidepresivo (146,6 frente a 307,7 días; pObjective: To determinate the impact of comorbidity, resource use and cost (healthcare and lost productivity on maintenance of remission of major depressive disorder in a Spanish population setting. Methods: We performed an observational, prospective, multicenter study using population databases. The inclusion criteria were age >18 years, first depressive episode between January 2003 and March 2007, with antidepressant prescription >60 days after the first prescription and a follow-up of at least 18 months (study

  7. Longitudinal Predictors of Institutionalization in Old Age.

    Directory of Open Access Journals (Sweden)

    André Hajek

    Full Text Available To investigate time-dependent predictors of institutionalization in old age using a longitudinal approach.In a representative survey of the German general population aged 75 years and older predictors of institutionalization were observed every 1.5 years over six waves. Conditional fixed-effects logistic regressions (with 201 individuals and 960 observations were performed to estimate the effects of marital status, depression, dementia, and physical impairments (mobility, hearing and visual impairments on the risk of admission to old-age home or nursing home. By exploiting the longitudinal data structure using panel econometric models, we were able to control for unobserved heterogeneity such as genetic predisposition and personality traits.The probability of institutionalization increased significantly with occurrence of widowhood, depression, dementia, as well as walking and hearing impairments. In particular, the occurrence of widowhood (OR = 78.3, dementia (OR = 154.1 and substantial mobility impairment (OR = 36.7 were strongly associated with institutionalization.Findings underline the strong influence of loss of spouse as well as dementia on institutionalization. This is relevant as the number of old people (a living alone and (b suffering from dementia is expected to increase rapidly in the next decades. Consequently, it is supposed that the demand for institutionalization among the elderly will increase considerably. Practitioners as well as policy makers should be aware of these upcoming challenges.

  8. Longitudinal Wobbling in $^{133}$La

    CERN Document Server

    Biswas, S; Garg, U; Bhat, G H; Frauendorf, S; Li, W; Sheikh, J A; Sethi, J; Saha, S; Singh, Purnima; Choudhury, D; Matta, J T; Ayangeakaa, A D; Dar, W >; Singh, V; Sihotra, S

    2016-01-01

    Excited states of $^{133}$La have been investigated to search for the wobbling excitation mode in the low-spin regime. Wobbling bands with $n_\\omega$ = 0 and 1 are identified along with the interconnecting $\\Delta I$ = 1, $E2$ transitions, which are regarded as fingerprints of the wobbling motion. An increase in wobbling frequency %of the $n_\\omega$ = 1 band with spin implies longitudinal wobbling for $^{133}$La, in contrast with the case of transverse wobbling observed in $^{135}$Pr. This is the first observation of a longitudinal wobbling band in nuclei. The experimental observations are accounted for by calculations using the quasiparticle triaxial rotor with harmonic frozen approximation and the triaxial projected shell model approaches, which attribute the appearance of longitudinal wobbling to the early alignment of an h$_{11/2}$ neutron pair.

  9. Longitudinal bulk acoustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja

    2009-01-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise i...

  10. Longitudinal health effects of disasters.

    NARCIS (Netherlands)

    Yzermans, C.J.

    2004-01-01

    Background: We carry out prospective, longitudinal studies on the possible health effects of two disasters in the Netherlands: the explosion of fireworks depot in a residential area (Enschede) and a fire in discotheque in Volendam. Learning from the chaotic aftermath previous disasters, the Dutch g

  11. Correspondence analysis of longitudinal data

    NARCIS (Netherlands)

    Van der Heijden, P.G.M.

    2005-01-01

    Correspondence analysis is an exploratory tool for the analysis of associations between categorical variables, the results of which may be displayed graphically. For longitudinal data with two time points, an analysis of the transition matrix (showing the relative frequencies for pairs of categories

  12. Long term and transitional intermittent smokers: a longitudinal study.

    OpenAIRE

    Lindström, Martin; Isacsson, Sven-Olof

    2002-01-01

    Objective: To investigate differences in snuff consumption, sociodemographic and psychosocial characteristics between baseline intermittent smokers that had become daily smokers, stopped smoking or remained intermittent smokers at the one year follow up. Design/setting/participants/measurements: A population of 12 507 individuals interviewed at baseline in 1992-94 and at a one year follow up, aged 45-69 years, was investigated in a longitudinal study. The three groups of baseline intermittent...

  13. Paediatric UK demyelinating disease longitudinal study (PUDDLS

    Directory of Open Access Journals (Sweden)

    Likeman Marcus

    2011-07-01

    Full Text Available Abstract Background There is evidence that at least 5% of Multiple sclerosis (MS cases manifest in childhood. Children with MS present with a demyelinating episode involving single or multiple symptoms prior to developing a second event (usually within two years to then meet criteria for diagnosis. There is evidence from adult cohorts that the incidence and sex ratios of MS are changing and that children of immigrants have a higher risk for developing MS. A paediatric population should reflect the vanguard of such changes and may reflect trends yet to be observed in adult cohorts. Studying a paediatric population from the first demyelinating event will allow us to test these hypotheses, and may offer further valuable insights into the genetic and environmental interactions in the pathogenesis of MS. Methods/Design The Paediatric UK Demyelinating Disease Longitudinal Study (PUDDLS is a prospective longitudinal observational study which aims to determine the natural history, predictors and outcomes of childhood CNS inflammatory demyelinating diseases. PUDDLS will involve centres in the UK, and will establish a cohort of children affected with a first CNS inflammatory demyelinating event for long-term follow up by recruiting for approximately 5 years. PUDDLS will also establish a biological sample archive (CSF, serum, and DNA, allowing future hypothesis driven research. For example, the future discovery of a biomarker will allow validation within this dataset for the evaluation of novel biomarkers. Patients will also be requested to consent to be contacted in the future. A secondary aim is to collaborate internationally with the International Paediatric Multiple Sclerosis Study Group when future collaborative studies are proposed, whilst sharing a minimal anonymised dataset. PUDDLS is the second of two jointly funded studies. The first (UCID-SS is an epidemiological surveillance study that already received ethical approvals, and started on the 1st

  14. Exploring Longitudinal Risk-return Relationships

    DEFF Research Database (Denmark)

    Andersen, Torben J.; Bettis, Richard A.

    2015-01-01

    We study a longitudinal fit model of adaptation and its association with the longitudinal risk-return relationship. The model allows the firm to adjust its position in response to partial learning about a changing environment characterized by two path-dependent processes—a random walk...... can lead to the inverse longitudinal risk-return relationships observed empirically. We discuss this apparent paradox and the possible resolution between mindless and conscious behavior as plausible causes of the longitudinal Bowman Paradox....

  15. A longitudinal study of food intake patterns and obesity in adult Danish men and women

    DEFF Research Database (Denmark)

    Togo, P; Osler, M; Sørensen, T I A

    2004-01-01

    OBJECTIVE: The aim of this study was to test the hypothesis that specific food intake patterns or changes in food intake patterns were related to future changes in body mass index (BMI). DESIGN: Longitudinal observational study, with clinical and questionnaire examinations at baseline and two fol...... factor scores, changes in factor scores and subsequent BMI changes or obesity were found. CONCLUSION: In this longitudinal study of a Danish population, food intake factors could not consistently predict changes in BMI or obesity development....

  16. Loss and gain cycles? A longitudinal study about burnout, engagement and self-efficacy

    OpenAIRE

    Susana Llorens-Gumbau; Marisa Salanova-Soria

    2014-01-01

    The present longitudinal study (two waves), conducted on a population of 274 secondary-school teachers, expands on previous research on burnout and work engagement. Accordingly, the effect of organizational factors (obstacles, facilitators) as well as personal resources (self-efficacy) on burnout and engagement is tested longitudinally following the Social Cognitive Theory. More specifically, we test the loss and gain cycles, and reciprocal relationships concerning burnout, engagement, and se...

  17. LONGITUDINAL LASER WIRE AT SNS

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, Alexander V [ORNL; Liu, Yun [ORNL; Zhukov, Alexander P [ORNL

    2014-01-01

    This paper describes a longitudinal H- beam profile scanner that utilizes laser light to detach convoy electrons and an MCP to collect and measure these electrons. The scanner is located in MEBT with H- energy of 2.5MeV and an RF frequency 402.5MHz. The picosecond pulsed laser runs at 80.5MHz in sync with the accelerator RF. The laser beam is delivered to the beam line through a 30m optical fiber. The pulse width after the fiber transmission measures about 10ps. Scanning the laser phase effectively allows measurements to move along ion bunch longitudinal position. We are able to reliably measure production beam bunch length with this method. The biggest problem we have encountered is background signal from electrons being stripped by vacuum. Several techniques of signal detection are discussed.

  18. Longitudinal dynamics in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Colton, E.P.

    1986-01-01

    The single-particle equations of motion are derived for charged particles in a storage ring. Longitudinal space charge is included in the potential assuming an infinitely conducting circular beam pipe with a distributed inductance. The framework uses Hamilton's equations with the canonical variables phi and W. The Twiss parameters for longitudinal motion are also defined for the small amplitude synchrotron oscillations. The space-charge Hamiltonian is calculated for both parabolic bunches and ''matched'' bunches. A brief analysis including second-harmonic rf contributions is also given. The final sections supply calculations of dynamical quantities and particle simulations with the space-charge effects neglected.

  19. Reconciling cross-sectional with longitudinal observations on annual decline.

    Science.gov (United States)

    Vollmer, W M

    1993-01-01

    In summary, numerous factors may contribute to observed differences between longitudinally and cross-sectionally derived measures of annual decline in lung function. The direction and magnitude of these differences appear hard to predict. Furthermore, although these differences can be minimized by careful modeling of the data, they cannot, in general, be completely avoided. It seems plausible, however, that both types of studies should give similar qualitative comparisons of risk factor effects if appropriately modeled. Longitudinal studies are likely to provide the most accurate and reliable estimates of lung function decline for both individuals and populations. Such data may be especially useful in identifying individuals with accelerated declines in lung function but who still have "normal" lung function as measured cross-sectionally. However, such studies require careful attention to quality control and typically require at least 4 years of follow-up before the noise in the data settles down. Multiple measurements, preferably four or more, are also necessary to reliably detect and adjust for survey effects. Cross-sectional studies, on the other hand, are simpler, cheaper, and quicker to conduct than are longitudinal studies. They may be particularly useful as a screening tool for identifying potentially affected or high-risk subjects (e.g., those with low levels of lung function) who may require further medical follow-up and/or ongoing monitoring. Both types of studies have a role in population-based occupational health hazard assessments.

  20. Longitudinal Space Charge in the SPS

    CERN Document Server

    Lasheen, Alexandre

    2016-01-01

    Longitudinal instabilities due to the SPS beam coupling impedance are a major issue for future projects and it is essential to have an accurate SPS impedance model to study them. The longitudinal space charge effect can be modelled by a pure reactive impedance and should also be included in simulations as it may have an impact at low energy. In this Note, the effect of the longitudinal space charge in the SPS is evaluated by taking into account the variation of the transverse beam size and vacuum chamber geometry along the ring. Scaling laws are used to investigate what are the most important parameters for the evaluation of the longitudinal space charge impedance.

  1. A Longitudinal Study of the Effects of Family Background Factors on Mathematics Achievements Using Quantile Regression

    Institute of Scientific and Technical Information of China (English)

    Xi-zhi Wu; Mao-zai Tian

    2008-01-01

    Quantile regression is gradually emerging as a powerful tool for estimating models of conditional quantile functions, and therefore research in this area has vastly increased in the past two decades. This paper, with the quantile regression technique, is the first comprehensive longitudinal study on mathematics participation data collected in Alberta, Canada. The major advantage of longitudinal study is its capability to separate the so-called cohort and age effects in the context of population studies. One aim of this paper is to study whether the family background factors alter performance on the mathematical achievement of the strongest students in the same way as that of weaker students based on the large longitudinal sample of 2000,2001 and 2002 mathematics participation longitudinal data set. The interesting findings suggest that there may be differential family background factor effects at different points in the mathematical achievement conditional distribution.

  2. College Women's Female Friendships: A Longitudinal View

    Science.gov (United States)

    Aleman, Ana M. Martinez

    2010-01-01

    This article presents a longitudinal qualitative study of the cognitive value of female friendships formed in college and seeks to appraise the meaning of the phenomenon for the participants. To grasp the temporal effects of the longitudinal data in this study, the author examines and assesses the relevant developmental literature, particularly…

  3. Longitudinal research in child and adolescent psychiatry.

    Science.gov (United States)

    Verhulst, F C; Koot, H M

    1991-05-01

    An indispensable approach to the study of variations in individual development and of causal mechanisms and processes underlying the course of psychopathology is the longitudinal method. In this introductory review, the strengths and weaknesses of longitudinal research are discussed, and factors hampering progress in this field are outlined. The many advantages of this approach warrant continuing efforts to develop strategies that minimize its drawbacks.

  4. [Longitudinal stent deformation during bifurcation lesion treatment].

    Science.gov (United States)

    Mami, Z; Monsegu, J

    2014-12-01

    Longitudinal stent deformation is defined as a compression of stent length after its implantation. It's a rare complication but dangerous seen with several stents. We reported a case of longitudinal stent deformation during bifurcation lesion treatment with a Promus Element(®) and we perform a short review of this complication.

  5. Longitudinal Single Bunch Instability Study on BEPCII

    CERN Document Server

    Dou, Wang; Zhe, Duan; Na, Wang; Li, Wang; Lin, Wang; Jie, Gao

    2013-01-01

    In order to study the single bunch longitudinal instability in BEPCII, experiments on the positron ring (BPR) for the bunch lengthening phenomenon were made. By analyzing the experimental data based on Gao's theory, the longitudinal loss factor for the bunch are obtained. Also, the total wake potential and the beam current threshold are estimated.

  6. LSTGEE: longitudinal analysis of neuroimaging data

    Science.gov (United States)

    Li, Yimei; Zhu, Hongtu; Chen, Yasheng; An, Hongyu; Gilmore, John; Lin, Weili; Shen, Dinggang

    2009-02-01

    Longitudinal imaging studies are essential to understanding the neural development of neuropsychiatric disorders, substance use disorders, and normal brain. Using appropriate image processing and statistical tools to analyze the imaging, behavioral, and clinical data is critical for optimally exploring and interpreting the findings from those imaging studies. However, the existing imaging processing and statistical methods for analyzing imaging longitudinal measures are primarily developed for cross-sectional neuroimaging studies. The simple use of these cross-sectional tools to longitudinal imaging studies will significantly decrease the statistical power of longitudinal studies in detecting subtle changes of imaging measures and the causal role of time-dependent covariate in disease process. The main objective of this paper is to develop longitudinal statistics toolbox, called LSTGEE, for the analysis of neuroimaging data from longitudinal studies. We develop generalized estimating equations for jointly modeling imaging measures with behavioral and clinical variables from longitudinal studies. We develop a test procedure based on a score test statistic and a resampling method to test linear hypotheses of unknown parameters, such as associations between brain structure and function and covariates of interest, such as IQ, age, gene, diagnostic groups, and severity of disease. We demonstrate the application of our statistical methods to the detection of the changes of the fractional anisotropy across time in a longitudinal neonate study. Particularly, our results demonstrate that the use of longitudinal statistics can dramatically increase the statistical power in detecting the changes of neuroimaging measures. The proposed approach can be applied to longitudinal data with multiple outcomes and accommodate incomplete and unbalanced data, i.e., subjects with different number of measurements.

  7. Violence against Pregnant Women Can Increase the Risk of Child Abuse: A Longitudinal Study

    Science.gov (United States)

    Chan, Ko Ling; Brownridge, Douglas A.; Fong, Daniel Y. T.; Tiwari, Agnes; Leung, Wing Cheong; Ho, Pak Chung

    2012-01-01

    Objective: To assess the impact of intimate partner violence (IPV) against pregnant women on subsequent perpetration of child abuse and neglect (CAN) by parents; and to test the mediation effect of recent IPV on the link between IPV during pregnancy and subsequent CAN. Methods: This study was a longitudinal follow-up of a population-based study on…

  8. Longitudinal data reveal ontogenetic changes in the wing morphology of a long-distance migratory bird

    NARCIS (Netherlands)

    de la Hera, Ivan; Pulido, Francisco; Visser, Marcel E.

    2014-01-01

    In migratory bird species, juveniles normally have shorter and more rounded wings than adults. The causes of this age-specific difference in wing morphology, however, are largely unknown. Here, we used longitudinal data collected over 3years from a Pied Flycatcher Ficedula hypoleuca population to as

  9. Longitudinal data reveal ontogenetic changes in the wing morphology of a long-distance migratory bird

    NARCIS (Netherlands)

    De la Hera, I.; Pulido, F.; Visser, M.E.

    2014-01-01

    In migratory bird species, juveniles normally have shorter and more rounded wings than adults. The causes of this age-specific difference in wing morphology, however, are largely unknown. Here, we used longitudinal data collected over 3 years from a Pied Flycatcher Ficedula hypoleuca population to a

  10. Untreated periodontal disease in Indonesian adolescents : Longitudinal clinical data and prospective clinical and microbiological risk assessment

    NARCIS (Netherlands)

    Timmerman, MF; Van der Weijden, GA; Abbas, F; Arief, EM; Armand, S; Winkel, EG; Van Winkelhoff, AJ; Van der Velden, U

    2000-01-01

    Background, aims: In order to investigate the role of various putative clinical and microbiological risk markers, a longitudinal study was initiated in a young population deprived of regular dental care. In 1987 all inhabitants in the age range 15-25 years living in a village with approximately 2000

  11. A longitudinal twin study of the direction of effects between ADHD symptoms and IQ

    NARCIS (Netherlands)

    Rommel, A.S.; Rijsdijk, F.; Greven, C.U.; Asherson, P.; Kuntsi, J.

    2015-01-01

    While the negative association between ADHD symptoms and IQ is well documented, our knowledge about the direction and aetiology of this association is limited. Here, we examine the association of ADHD symptoms with verbal and performance IQ longitudinally in a population-based sample of twins. In a

  12. Longitudinal dynamics and tomography in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Stogin, J. [Princeton Univ., Princeton, NJ (United States); Sen, T. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Moore, R. S. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2012-01-10

    Motivated by the desire to understand the longitudinal effects of beam-beam forces, we study the longitudinal dynamics of protons and anti-protons at injection and top energy in the Tevatron. Multi-turn data of the longitudinal profiles are captured to reveal information about frequencies of oscillation, and changes in the bunch distributions. Tomographic reconstruction is used to create phase space maps which are subsequently used to find the momentum distributions. Changes in these distributions for both proton and anti-proton beams are also followed through the operational cycle. We report too on the details of interesting dynamics and some unexpected findings.

  13. Longitudinal oscillation of launch vehicles

    Science.gov (United States)

    Glaser, R. F.

    1973-01-01

    During powered flight a vehicle may develop longitudinal self-excited oscillations, so-called oscillations, of its structure. The energy supplying the vibration is tapped from the thrust by the activity of the system itself; that is, oscillation of the structure causes oscillation of the propellant system, especially of the pumps. In this way an oscillating thrust can be created that, by a feedback loop, may sustain the structural oscillation under certain circumstances. Two special features of the system proved to be essential for creation of instability. One is the effect of the inherent time interval that the thrust oscillation is lagging behind the structural oscillation. The other is the decreased of system mass caused by the exhausting of gas. The latter feature may cause an initially stable system to become unstable. To examine the stability of the system, a single mass-spring model, which is the result of a one-term Galerkin approach to the equation of motion, has been considered. The Nyquist stability criterion leads to a stability graph that shows the stability conditions in terms of the system parameter and also demonstrates the significance of time lag, feedback magnitude, and loss of mass. An important conclusion can be drawn from the analysis: large relative displacements of the pump-engine masses favor instability. This is also confirmed by flight measurements.

  14. Longitudinal Variations in Jupiter's Winds

    Science.gov (United States)

    Simon-Miller, Amy A.; Gierasch, P. J.; Tierney, G.

    2010-01-01

    Long-term studies of Jupiter's zonal wind field revealed temporal variations on the order of 20 to 40 m/s at many latitudes, greater than the typical data uncertainties of 1 to 10 m/s. No definitive periodicities were evident, however, though some latitudinally-confined signals did appear at periods relevant to the Quasi- Quadrennial Oscillation (Simon-Miller & Gierasch, Icarus, in press). As the QQO appears, from vertical temperature profiles, to propagate downward, it is unclear why a signal is not more obvious, unless other processes dominate over possibly weaker forcing from the QQO. An additional complication is that zonal wind profiles represent an average over some particular set of longitudes for an image pair and most data sets do not offer global wind coverage. Lien avoiding known features, such as the large anticyclonic vortices especially prevalent in the south, there can be distinct variations in longitude. We present results on the full wind field from Voyager and Cassini data, showing apparent longitudinal variations of up to 60 m/s or more. These are particularly obvious near disruptions such as the South Equatorial Disturbance, even when the feature itself is not clearly visible. These two dates represent very different states of the planet for comparison: Voyagers 1 & 2 flew by Jupiter shortly after a global upheaval, while many regions were in a disturbed state, while the Cassini view is typical of a more quiescent period present during much of the 1990s and early 2000s.

  15. Cohort profile: the Quebec Longitudinal Study of Kindergarten Children (QLSKC).

    Science.gov (United States)

    Rouquette, Alexandra; Côté, Sylvana M; Pryor, Laura E; Carbonneau, René; Vitaro, Frank; Tremblay, Richard E

    2014-02-01

    The Quebec Longitudinal Study of Kindergarten Children (QLSKC) is an ongoing population-based prospective longitudinal study presently spanning ages 6-29 years, designed to study the prevalence, risk factors, development and consequences of behavioural and emotional problems during elementary school. Kindergarten boys and girls attending French-speaking public schools in the Canadian province of Quebec during the 1986-87 and 1987-88 school years were included in the cohort: 2000 children representative of the population and 1017 children exhibiting disruptive behaviour problems. To date, 12 waves of data have been collected, and three generations of participants have been involved in the study (i.e. the study child, his parents and the first child of the study child). Information on demographics, psycho-social and lifestyle factors, child and family member characteristics (physical and mental health), and outcomes such as psychiatric diagnoses, delinquency or school diploma were assessed during three important developmental stages (childhood, adolescence and early adulthood). Blood samples were also collected in early adulthood for genetic analyses. Information on publications, available data and access to data can be found on the following website (http://www.gripinfo.ca/Grip/Public/www/).

  16. Longitudinal research strategies: advantages, problems, and prospects.

    Science.gov (United States)

    Farrington, D P

    1991-05-01

    The single-cohort, long-term longitudinal survey has many advantages in comparison with a cross-sectional survey in advancing knowledge about offending and other types of psychopathology, notably in providing information about onset and desistance, about continuity and prediction, and about within-individual change. However, the longitudinal survey also has significant problems, notably in confounding aging and period effects, delayed results, achieving continuity in funding and research direction, and cumulative attrition. This paper suggests the use of a multiple-cohort sequential strategy (the "accelerated longitudinal design") as a way of achieving the benefits of the longitudinal method while minimizing the problems in advancing knowledge about the natural history, causes, prevention, and treatment of psychopathological disorders.

  17. Longitudinally extensive optic neuritis in pediatric patients.

    Science.gov (United States)

    Graves, Jennifer; Kraus, Verena; Soares, Bruno P; Hess, Christopher P; Waubant, Emmanuelle

    2015-01-01

    Extensive optic nerve demyelinating lesions on magnetic resonance imaging (MRI) in adults could indicate a diagnosis other than multiple sclerosis with worse prognosis such as neuromyelitis optica. We report the frequency of longitudinally extensive lesions in children with first events of optic neuritis. Subjects had brain or orbit MRI within 3 months of onset and were evaluated at the University of California, San Francisco, Pediatric Multiple Sclerosis Center. Lesion length, determined by T2 hyperintensity or contrast enhancement, was blindly graded as absent, focal or longitudinally extensive (at least 2 contiguous segments of optic nerve). Of 25 subjects, 9 (36%) had longitudinally extensive optic neuritis. Extensive lesions were not associated with non-multiple sclerosis versus multiple sclerosis diagnosis (P = 1.00). No association between age and lesion extent was observed (P = .26). Prospective studies are needed to determine if longitudinally extensive optic neuritis can predict visual outcome.

  18. Genetic and Environmental Regulation on Longitudinal Change of Metabolic Phenotypes in Danish and Chinese Adult Twins

    DEFF Research Database (Denmark)

    Li, Shuxia; Kyvik, Kirsten Ohm; Pang, Zengchang

    2016-01-01

    OBJECTIVE: The rate of change in metabolic phenotypes can be highly indicative of metabolic disorders and disorder-related modifications. We analyzed data from longitudinal twin studies on multiple metabolic phenotypes in Danish and Chinese twins representing two populations of distinct ethnic...... environmental contribution to blood pressure but no genetic contribution to longitudinal change in body mass traits. CONCLUSION: Our results emphasize the major contribution of unique environment to the observed intra-individual variation in all metabolic phenotypes in both samples, and meanwhile reveal...... differential patterns of genetic and common environmental regulation on changes over time in metabolic phenotypes across the two samples....

  19. Common predictor effects for multivariate longitudinal data

    OpenAIRE

    Jia, Juan; Weiss, Robert E.

    2009-01-01

    Multivariate outcomes measured longitudinally over time are common in medicine, public health, psychology and sociology. The typical (saturated) longitudinal multivariate regression model has a separate set of regression coefficients for each outcome. However, multivariate outcomes are often quite similar and many outcomes can be expected to respond similarly to changes in covariate values. Given a set of outcomes likely to share common covariate effects, we propose the Clustered Outcome COmm...

  20. Marital assortment and phenotypic convergence: longitudinal evidence.

    Science.gov (United States)

    Caspi, A; Herbener, E S

    1993-01-01

    This study provides a direct test of whether the observed similarity of spouses is due to initial assortment rather than to convergence of phenotypes. With data from three well-known longitudinal studies, phenotypic convergence is examined using both variable- and person-centered analyses. The longitudinal evidence does not support the hypothesis that couples increasingly resemble each other with time. Spouse correlations most likely reflect initial assortment at marriage and not the convergence of phenotypes.

  1. Counting Populations

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    Scientists use sampling to get an estimate of things they cannot easily count. A population is made up of all the organisms of one species living together in one place at the same time. All of the people living together in one town are considered a population. All of the grasshoppers living in a field are a population. Scientists keep track of the…

  2. Application of a dynamic population-based model for evaluation of exposure reduction strategies in the baking industry

    NARCIS (Netherlands)

    Meijster, T.; Warren, N.; Heederik, D.; Tielemans, E.

    2009-01-01

    Recently a dynamic population model was developed that simulates a population of bakery workers longitudinally through time and tracks the development of work-related sensitisation and respiratory symptoms in each worker. Input for this model comes from cross-sectional and longitudinal epidemiologic

  3. Population-level correlates of preterm delivery among black and white women in the U.S.

    Directory of Open Access Journals (Sweden)

    Suzan L Carmichael

    Full Text Available OBJECTIVE: This study examined the ability of social, demographic, environmental and health-related factors to explain geographic variability in preterm delivery among black and white women in the US and whether these factors explain black-white disparities in preterm delivery. METHODS: We examined county-level prevalence of preterm delivery (20-31 or 32-36 weeks gestation among singletons born 1998-2002. We conducted multivariable linear regression analysis to estimate the association of selected variables with preterm delivery separately for each preterm/race-ethnicity group. RESULTS: The prevalence of preterm delivery varied two- to three-fold across U.S. counties, and the distributions were strikingly distinct for blacks and whites. Among births to blacks, regression models explained 46% of the variability in county-level risk of delivery at 20-31 weeks and 55% for delivery at 32-36 weeks (based on R-squared values. Respective percentages for whites were 67% and 71%. Models included socio-environmental/demographic and health-related variables and explained similar amounts of variability overall. CONCLUSIONS: Much of the geographic variability in preterm delivery in the US can be explained by socioeconomic, demographic and health-related characteristics of the population, but less so for blacks than whites.

  4. Longitudinal trajectories of aberrant behavior in fragile X syndrome.

    Science.gov (United States)

    Hustyi, Kristin M; Hall, Scott S; Jo, Booil; Lightbody, Amy A; Reiss, Allan L

    2014-11-01

    The Aberrant Behavior Checklist-Community (ABC-C; Aman et al., 1995) has been increasingly adopted as a primary tool for measuring behavioral change in clinical trials for individuals with fragile X syndrome (FXS). To our knowledge, however, no study has documented the longitudinal trajectory of aberrant behaviors in individuals with FXS using the ABC-C. As part of a larger longitudinal study, we examined scores obtained on the ABC-C subscales for 124 children and adolescents (64 males, 60 females) with FXS who had two or more assessments (average interval between assessments was approximately 4 years). Concomitant changes in age-equivalent scores on the Vineland Adaptive Behavior Scales (VABS) were also examined. As expected for an X-linked genetic disorder, males with FXS obtained significantly higher scores on all subscales of the ABC-C and significantly lower age-equivalent scores on the VABS than females with FXS. In both males and females with FXS, scores on the Irritability/Agitation and Hyperactivity/Noncompliance subscales of the ABC-C decreased significantly with age, with little to no change occurring over time on the Lethargy/Social Withdrawal, Stereotypic Behavior, and Inappropriate Speech subscales. The decrease in scores on the Hyperactivity/Noncompliance domain was significantly greater for males than for females. In both males and females, age-equivalent scores on the VABS increased significantly over this developmental period. These results establish a basis upon which to evaluate long-term outcomes from intervention-based research. However, longitudinal direct observational studies are needed to establish whether the severity of problem behavior actually decreases over time in this population.

  5. Joint multiple imputation for longitudinal outcomes and clinical events that truncate longitudinal follow-up.

    Science.gov (United States)

    Hu, Bo; Li, Liang; Greene, Tom

    2016-07-30

    Longitudinal cohort studies often collect both repeated measurements of longitudinal outcomes and times to clinical events whose occurrence precludes further longitudinal measurements. Although joint modeling of the clinical events and the longitudinal data can be used to provide valid statistical inference for target estimands in certain contexts, the application of joint models in medical literature is currently rather restricted because of the complexity of the joint models and the intensive computation involved. We propose a multiple imputation approach to jointly impute missing data of both the longitudinal and clinical event outcomes. With complete imputed datasets, analysts are then able to use simple and transparent statistical methods and standard statistical software to perform various analyses without dealing with the complications of missing data and joint modeling. We show that the proposed multiple imputation approach is flexible and easy to implement in practice. Numerical results are also provided to demonstrate its performance. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Longitudinal surface structures (flowstripes on Antarctic glaciers

    Directory of Open Access Journals (Sweden)

    N. F. Glasser

    2011-11-01

    Full Text Available Longitudinal surface structures (''flowstripes'' are common on many glaciers but their origin and significance are poorly understood. In this paper we present observations of the development of these longitudinal structures from four different Antarctic glacier systems (the Lambert Glacier/Amery Ice Shelf area, outlet glaciers in the Ross Sea sector, ice-shelf tributary glaciers on the Antarctic Peninsula, and the onset zone of a tributary to the Recovery Glacier Ice Stream in the Filchner Ice Shelf area. Mapping from optical satellite images demonstrates that longitudinal surface structures develop in two main situations: (1 as relatively wide flow stripes within glacier flow units and (2 as relatively narrow flow stripes where there is convergent flow around nunataks or at glacier confluence zones. Our observations indicate that the confluence features are narrower, sharper, and more clearly defined features. They are characterised by linear troughs or depressions on the ice surface and are much more common than the former type. Longitudinal surface structures within glacier flow units have previously been explained as the surface expression of localised bed perturbations but a universal explanation for those forming at glacier confluences is lacking. Here we propose that these features are formed at zones of ice acceleration and extensional flow at glacier confluences. We provide a schematic model for the development of longitudinal surface structures based on extensional flow that can explain their ridge and trough morphology as well as their down-ice persistence.

  7. Longitudinal stability in multiharmonic standing wave linacs

    Science.gov (United States)

    Carver, L. R.; Jones, R. M.; Jiang, Y.; Hirshfield, J. L.

    2016-09-01

    Accelerating cavities that excite multiple modes at integer harmonics of the fundamental frequency have the potential to be used to suppress the onset of rf breakdown and reduce the pulsed surface heating at high accelerating gradients. Understanding the effect of an additional harmonic cavity mode on the longitudinal beam dynamics is important to their development and use. A Hamiltonian that describes the longitudinal motion of a particle as it traverses a chain of multiharmonic cavities has been derived and is applied to the case of a second harmonic cavity. The Hamiltonian is based upon formalisms found in literature for the fundamental harmonic and is extended to include different longitudinal field distributions and harmonic frequencies. The study initially explores the longitudinal motion for moderate accelerating gradients with high-β protons, as this will allow fundamental properties of the stable region (acceptance and shape of the rf bucket) to be determined. High accelerating gradients are also investigated but the focus will be on phase stability throughout. This work concludes by considering the longitudinal dynamics of a modified European Spallation Source accelerator, comprised of multiharmonic cavities that has specifications broadly consistent with the accelerator.

  8. Longitudinal fluctuations and decorrelation of anisotropic flow

    Science.gov (United States)

    Pang, Long-Gang; Petersen, Hannah; Qin, Guang-You; Roy, Victor; Wang, Xin-Nian

    2016-12-01

    We investigate the decorrelation of 2nd and 3rd order anisotropic flow for charged particles in two different pseudo rapidity (η) windows by varying the pseudo rapidity gap, in an event-by-event (3+1)D ideal hydrodynamic model, with fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. We visualize the parton distribution at initial state for Pb+Pb collisions at LHC and Au+Au collisions at RHIC, and demonstrate the longitudinal fluctuations originating from the asymmetry between forward and backward going participants, the fluctuations of the string length and the fluctuations due to finite number of partons at different beam energies. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation than at LHC, indicating larger longitudinal fluctuations at lower beam energies.

  9. Promoting Population

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    THE world's population reached 5 billion in 1987,then 6 billion in 1999;now,in 2011,it is 7 billion.For a country with a set birth control policy,the way in which Chinese people and the media view this number has greatly changed.People are increasingly reflecting on the concept of population from a more scientific and rational perspective.This shift is a change from how people perceived population in the past.

  10. Diet assessment in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil: Development of a food frequency questionnaire

    Directory of Open Access Journals (Sweden)

    Maria del Carmen Bisi Molina

    2013-04-01

    Full Text Available OBJECTIVE: The objective of this article is to present the development of the Food Frequency Questionaire used in the Longitudinal Study of Adult Health-Brazil and analyze how diet exposes individuals to cardiovascular diseases and type 2 diabetes Mellitus. METHODS: The Longitudinal Study of Adult Health-Brazil dietary assessment instrument is based on a previously validated Food Frequency Questionaire and the final list of items took into consideration a study done in the six Longitudinal Study of Adult Health-Brazil investigation centers. RESULTS: New foods/preparations were included in the Food Frequency Questionaire with their respective portions, totaling 114 items. The perspectives of dietary analysis and cardiovascular diseases and diabetes are presented in Longitudinal Study of Adult Health-Brazil. CONCLUSION: A new instrument was developed to cover the regional particularities of the study population.

  11. Longitudinal measurement invariance, stability and change of anger and cynicism.

    Science.gov (United States)

    Hakulinen, Christian; Jokela, Markus; Keltikangas-Järvinen, Liisa; Merjonen, Päivi; Raitakari, Olli T; Hintsanen, Mirka

    2014-06-01

    Anger and hostility are key concepts in behavioral medicine, but little is known about their stability over life course. A sample of 3,074 individuals from six age groups (aged 15-30 at the baseline) were selected from a population-based study to examine longitudinal measurement invariance, stability and change in anger and cynicism from early to middle adulthood over 15 years. Cynicism, a facet of hostility, and anger were measured 4 times in 1992, 1997, 2001 and 2007. Final longitudinal measurement invariance models achieved partial strict measurement invariance, indicating good measurement consistency over time. Rank-order stability of anger and cynicism was found to be moderate. Mean levels of anger and cynicism decreased over time, but in anger the decline was faster among women. The variance of anger and cynicism also increased over time, but in cynicism the rate of change was higher among men. Altogether, anger and cynicism show measurement invariance and moderate stability from early adulthood to middle adulthood.

  12. Longitudinal Study of Body Mass Index in Young Males and the Transition to Fatherhood

    Science.gov (United States)

    Garfield, Craig F.; Duncan, Greg; Gutina, Anna; Rutsohn, Joshua; McDade, Thomas W.; Adam, Emma K.; Coley, Rebekah Levine; Chase-Lansdale, P. Lindsay

    2017-01-01

    Despite a growing understanding that the social determinants of health have an impact on body mass index (BMI), the role of fatherhood on young men’s BMI is understudied. This longitudinal study examines BMI in young men over time as they transition from adolescence into fatherhood in a nationally representative sample. Data from all four waves of the National Longitudinal Study of Adolescent Health supported a 20-year longitudinal analysis of 10,253 men beginning in 1994. A “fatherhood-year” data set was created and changes in BMI were examined based on fatherhood status (nonfather, nonresident father, resident father), fatherhood years, and covariates. Though age is positively associated with BMI over all years for all men, comparing nonresident and resident fathers with nonfathers reveals different trajectories based on fatherhood status. Entrance into fatherhood is associated with an increase in BMI trajectory for both nonresident and resident fathers, while nonfathers exhibit a decrease over the same period. In this longitudinal, population-based study, fatherhood and residence status play a role in men’s BMI. Designing obesity prevention interventions for young men that begin in adolescence and carry through young adulthood should target the distinctive needs of these populations, potentially improving their health outcomes. PMID:26198724

  13. Longitudinal coupling effect in microfiber Bragg gratings

    Science.gov (United States)

    Zhao, Ping; Zhang, Jihua; Wang, Guanghui; Jiang, Meng; Ping Shum, Perry; Zhang, Xinliang

    2012-10-01

    We theoretically present longitudinal coupling effect (LCE) in air-cladding microfiber Bragg gratings (MFBGs). Distinct from conventional weakly-guiding optical fibers, large longitudinal electric field (Ez) exists in wavelength-scale microfibers. Due to LCE, MFBG reflectivity can be reduced by more than 30% within the band-gap and the full width at half maximum (FWHM) is obviously narrowed. This theoretical analytical work is instructive to precisely design and fabricate MFBGs that are promising in the areas of optical sensing and nanophotonics.

  14. LHC MD 232: Longitudinal Impedance Evaluation

    CERN Document Server

    Esteban Muller, Juan; Baudrenghien, Philippe; Shaposhnikova, Elena; CERN. Geneva. ATS Department

    2017-01-01

    The aim of the MDstudies presented here was to evaluate the imaginary part of the longitudinal impedance of the LHC by means of synchrotron frequency shift measurements. Single bunches with similar longitudinal emittance but different intensities were studied at flat top. Based on the beam parameters, a maximum shift of about 0.2 Hz was expected between the different bunches. A detailed analysis still needs to be carried out to determine the measured synchrotron frequency shift. The measurements took place between 8:00 p.m. on 26th and 2:00 a.m. on 27th July 2016

  15. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  16. The nutritional situation in Swedish nursing homes - a longitudinal study.

    Science.gov (United States)

    Borgström Bolmsjö, Beata; Jakobsson, Ulf; Mölstad, Sigvard; Ostgren, Carl Johan; Midlöv, Patrik

    2015-01-01

    Poor nutritional status is widespread among the elderly and is associated with increased morbidity and mortality. The aim of this study was to longitudinally describe the nutritional status in elderly people living in nursing homes. Nutritional status was recorded longitudinally in elderly people living in 11 different nursing homes in Sweden. Participants were examined at baseline by specially trained nurses who also assisted with questionnaires and collected data for current medical treatment from patient records. Nutritional status was evaluated at baseline and after 24 months with the mini nutritional assessment (MNA). The study included 318 subjects. The mean age of the participants was 85.0 years (range 65-101). At baseline, 41.6% were well nourished, 40.3% at risk of malnutrition, and 17.7% malnourished according to the MNA. Survival was significantly lower in the malnourished group. After 24 months, almost half of the population had died. The group of participants who survived at 24 months represents a population of better nutritional state, where 10.6% were malnourished at baseline increasing to 24.6% after 24 months. After 24 months, 38.7% of the participants showed a decline in nutritional state. The group with deteriorating MNA scores had higher weight, BMI values, and a higher hospitalization rate. The prevalence of malnutrition in nursing home residents increased over time and it is important to evaluate nutritional state regularly. Nutritional interventions should be considered in better nourished groups, as well as in malnourished individuals, to prevent a decline in nutritional state.

  17. Imaginary populations

    Directory of Open Access Journals (Sweden)

    A. Martínez–Abraín

    2010-01-01

    Full Text Available A few years ago, Camus & Lima (2002 wrote an essay to stimulate ecologists to think about how we define and use a fundamental concept in ecology: the population. They concluded, concurring with Berryman (2002, that a population is "a group of individuals of the same species that live together in an area of sufficient size to permit normal dispersal and/or migration behaviour and in which population changes are largely the results of birth and death processes". They pointed out that ecologists often forget "to acknowledge that many study units are neither natural nor even units in terms of constituting a population system", and hence claimed that we "require much more accuracy than in past decades in order to be more effective to characterize populations and predict their behaviour". They stated that this is especially necessary "in disciplines such as conservation biology or resource pest management, to avoid reaching wrong conclusions or making inappropriate decisions". As a population ecologist and conservation biologist I totally agree with these authors and, like them, I be¬lieve that greater precision and care is needed in the use and definition of ecological terms. The point I wish to stress here is that we ecologists tend to forget that when we use statistical tools to infer results from our sample to a population we work with what statisticians term "imaginary", "hypothetical" or "potential" popula¬tions. As Zar (1999 states, if our sample data consist of 40 measurements of growth rate in guinea pigs "the population about which conclusions might be drawn is the growth rates of all the guinea pigs that conceivably might have been administered the same food supplement under identical conditions". Such a population does not really exist, and hence it is considered a hypothetical or imaginary population. Compare that definition with the population concept that would be in our minds when performing such measurements. We would probably

  18. Population policy.

    Science.gov (United States)

    1987-03-01

    Participants in the Seminar on Population Policies for Top-level Policy Makers and Program Managers, meeting in Thailand during January 1987, examined the challenges now facing them regarding the implementation of fertility regulation programs in their respective countries -- Bangladesh, China, India, Indonesia, Malaysia, Nepal, Pakistan, the Philippines, the Republic of Korea, and Thailand. This Seminar was organized to coincide with the completion of an Economic and Social Commission for Asia and the Pacific (ESCAP) study investigating the impact and efficiency of family planning programs in the region. Country studies were reviewed at the Seminar along with policy issues about the status of women, incentive and disincentive programs, and socioeconomic factors affecting fertility. In Bangladesh the government recognizes population growth as its top priority problem related to the socioeconomic development of the country and is working to promote a reorientation strategy from the previous clinic-oriented to a multidimensional family welfare program. China's family planning program seeks to postpone marraige, space the births of children between 3-5 years, and promote the 1-child family. Its goal is to reduce the rate of natural increase from 12/1000 in 1978 to 5/1000 by 1985 and 0 by 2000. India's 7th Five-Year-Plan (1986-90) calls for establishing a 2-child family norm by 2000. In Indonesia the government's population policy includes reducing the rate of population growth, achieving a redistribution of the population, adjusting economic factors, and creating prosperous families. The government of Indonesia reversed its policy to reduce the population growth rate in 1984 and announced its goal of achieving a population of 70 million by 2100 in order to support mass consumption industries. It has created an income tax deduction system favoring large families and maternity benefits for women who have up to 5 children as incentives. Nepal's official policy is to

  19. An electromagnetic shashlik calorimeter with longitudinal segmentation

    CERN Document Server

    Benvenuti, Alberto C; Camporesi, T; Checchia, P; Fenyuk, A; Hedberg, V; Lishin, V A; Margoni, M; Mazzucato, M; Obraztsov, V F; Paganoni, M; Polyakov, V A; Simonetto, F; Terranova, F; Vlasov, E

    1999-01-01

    A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and $e/\\pi$ separation are reported.

  20. The longitudinal static stability of tailless aircraft

    OpenAIRE

    de Castro, Helena V.

    2001-01-01

    This paper describes the development of a simple theory of the longitudinal controls fixed static stability of tailless aeroplanes. The classical theory, as developed for the conventional aircraft, is modified to accommodate the particular features of the tailless aeroplanes. The theory was then applied to a particular blended-wing-body tailless civil transport aircraft, BWB-98. Cranfield University

  1. Biomechanics of Distance Running: A Longitudinal Study

    Science.gov (United States)

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  2. Investigating Ceiling Effects in Longitudinal Data Analysis

    Science.gov (United States)

    Wang, Lijuan; Zhang, Zhiyong; McArdle, John J.; Salthouse, Timothy A.

    2008-01-01

    Score limitation at the top of a scale is commonly termed "ceiling effect." Ceiling effects can lead to serious artifactual parameter estimates in most data analysis. This study examines the consequences of ceiling effects in longitudinal data analysis and investigates several methods of dealing with ceiling effects through Monte Carlo simulations…

  3. Dual imputation model for incomplete longitudinal data

    NARCIS (Netherlands)

    Jolani, S.; Frank, L.E.; Buuren, S. van

    2014-01-01

    Missing values are a practical issue in the analysis of longitudinal data. Multiple imputation (MI) is a well-known likelihood-based method that has optimal properties in terms of efficiency and consistency if the imputation model is correctly specified. Doubly robust (DR) weighing-based methods pro

  4. Emotion Regulation and Childhood Aggression: Longitudinal Associations

    Science.gov (United States)

    Roll, Judith; Koglin, Ute; Petermann, Franz

    2012-01-01

    Accumulating evidence suggests that emotion dysregulation is associated with psychopathology. This paper provides a review of recent longitudinal studies that investigate the relationship between emotion regulation and aggressive behavior in childhood age. While there is substantial evidence for assuming a close relation of emotion regulation and…

  5. [Posterior longitudinal ligament ossification: case report].

    Science.gov (United States)

    Tella, Oswaldo Inácio de; Herculano, Marco Antonio; Paiva Neto, Manoel Antonio; Faedo Neto, Atílio; Crosera, João Francisco

    2006-03-01

    Posterior longitudinal ligament ossification of cervical spine is a rare condition among caucasians. A 42 years old japanese patient with progressive walking difficulty was diagnosed with this pathology by CT scan and MRI and treated surgically by an anterior approach with arthrodesis. Pathophysiology, racial prevalence, clinical picture, radiological characteristics and surgical approaches options are revised.

  6. Longitudinal bulk a coustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja;

    2009-01-01

    Design, fabrication and characterization, in terms of mass sensitivity, is presented for a polycrystalline silicon longitudinal bulk acoustic cantilever. The device is operated in air at 51 MHz, resulting in a mass sensitivity of 100 HZ/fg (1 fg = 10{su−15 g). The initial characterization...

  7. Longitudinal photosynthetic gradient in crust lichens' thalli.

    Science.gov (United States)

    Wu, Li; Zhang, Gaoke; Lan, Shubin; Zhang, Delu; Hu, Chunxiang

    2014-05-01

    In order to evaluate the self-shading protection for inner photobionts, the photosynthetic activities of three crust lichens were detected using Microscope-Imaging-PAM. The false color images showed that longitudinal photosynthetic gradient was found in both the green algal lichen Placidium sp. and the cyanolichen Peltula sp. In longitudinal direction, all the four chlorophyll fluorescence parameters Fv/Fm, Yield, qP, and rETR gradually decreased with depth in the thalli of both of these two lichens. In Placidium sp., qN values decreased with depth, whereas an opposite trend was found in Peltula sp. However, no such photosynthetic heterogeneity was found in the thalli of Collema sp. in longitudinal direction. Microscope observation showed that photobiont cells are compactly arranged in Placidium sp. and Peltula sp. while loosely distributed in Collema sp. It was considered that the longitudinal photosynthetic heterogeneity was ascribed to the result of gradual decrease of incidence caused by the compact arrangement of photobiont cells in the thalli. The results indicate a good protection from the self-shading for the inner photobionts against high radiation in crust lichens.

  8. Burnout development among dentists: a longitudinal study

    NARCIS (Netherlands)

    H. te Brake; N. Smits; J.M. Wicherts; R.C. Gorter; J. Hoogstraten

    2008-01-01

    Knowledge on the development of burnout among dentists is important for purposes of prevention and intervention. Using a two-wave longitudinal design, this study examined the chronological sequence of the three dimensions of the Maslach Burnout Inventory: emotional exhaustion; depersonalization; and

  9. Psychological risk factors for compulsive exercise : a longitudinal investigation of adolescent boys and girls

    OpenAIRE

    Goodwin, Huw; Haycraft, Emma; Meyer, Caroline

    2014-01-01

    Compulsive exercise is associated with unhealthy outcomes and is common among eating disorder populations. This study aimed to replicate previous cross-sectional work by considering psychological characteristics as longitudinal predictors of compulsive exercise. A sample of 369 adolescents (n = 221 female, n = 148 male) completed measures of compulsive exercise, eating disorder psychopathology, obsessive–compulsiveness, perfectionism, anxiety, and depression at baseline, and a measure of comp...

  10. Body Image Distortions, Weight, and Depression in Adolescent Boys: Longitudinal Trajectories into Adulthood

    OpenAIRE

    Blashill, Aaron J.; Wilhelm, Sabine

    2013-01-01

    Depressive symptoms are common among the U.S. population, yet research into prospective risk factors of depression among men is limited. Distorted body image is also prevalent among adolescent boys, and may be linked with elevated depression; however, longitudinal associations have rarely been measured. Thus, the aim of the current study was to assess the prospective relationship between forms of body image distortion and depressive symptoms among adolescent boys, into adulthood. Data were ex...

  11. Effect of Helicobacter pylori infection on growth trajectories in young Ethiopian children: a longitudinal study

    OpenAIRE

    Bineyam Taye; Fikre Enquselassie; Aster Tsegaye; Alemayehu Amberbir; Girmay Medhin; Andrew Fogarty; Karen Robinson; Gail Davey

    2016-01-01

    Background: Helicobacter pylori infection has been associated with early childhood growth impairment in high- and middle-income countries; however, few studies have examined this relationship within low-income countries or have used a longitudinal design. The possible effects of H. pylori infection on growth trajectories were examined in a cohort of young Ethiopian children. Methods: In 2011/12, 856 children (85.1% of the 1006 original singletons in a population-based birth cohort) were fo...

  12. Parental feeding practices and child weight status in Mexican American families: a longitudinal analysis

    OpenAIRE

    Tschann, JM; Martinez, SM; Penilla, C; Gregorich, SE; Pasch, LA; de Groat, CL; Flores, E; Deardorff, J; Greenspan, LC; Butte, NF

    2015-01-01

    Background Parental feeding practices are thought to influence children’s weight status, through children’s eating behavior and nutritional intake. However, because most studies have been cross-sectional, the direction of influence is unclear. Moreover, although obesity rates are high among Latino children, few studies of parental feeding practices have focused on this population. Methods This 2-year longitudinal study examined mutual influences over time between parental feeding practices an...

  13. Time-varying effect modeling with longitudinal data truncated by death: conditional models, interpretations, and inference.

    Science.gov (United States)

    Estes, Jason P; Nguyen, Danh V; Dalrymple, Lorien S; Mu, Yi; Şentürk, Damla

    2016-05-20

    Recent studies found that infection-related hospitalization was associated with increased risk of cardiovascular (CV) events, such as myocardial infarction and stroke in the dialysis population. In this work, we develop time-varying effects modeling tools in order to examine the CV outcome risk trajectories during the time periods before and after an initial infection-related hospitalization. For this, we propose partly conditional and fully conditional partially linear generalized varying coefficient models (PL-GVCMs) for modeling time-varying effects in longitudinal data with substantial follow-up truncation by death. Unconditional models that implicitly target an immortal population is not a relevant target of inference in applications involving a population with high mortality, like the dialysis population. A partly conditional model characterizes the outcome trajectory for the dynamic cohort of survivors, where each point in the longitudinal trajectory represents a snapshot of the population relationships among subjects who are alive at that time point. In contrast, a fully conditional approach models the time-varying effects of the population stratified by the actual time of death, where the mean response characterizes individual trends in each cohort stratum. We compare and contrast partly and fully conditional PL-GVCMs in our aforementioned application using hospitalization data from the United States Renal Data System. For inference, we develop generalized likelihood ratio tests. Simulation studies examine the efficacy of estimation and inference procedures.

  14. [Population education].

    Science.gov (United States)

    Niang, M

    1992-12-01

    Africa has the highest population growth rate in the world (3%). It has 650 million people (about 900 million in 2000). Rapid population growth has serious consequences which, if not addressed, will be disastrous. This worrisome situation has led some governments to adopt demographic policies to slow down population growth. The UN Economic, Scientific and Cultural Organization (UNESCO) recommends that schools provide population education. Various population conferences have popularized population education in schools among African countries. UNESCO began its regional program on population education in Africa in 1969. National family life and population education (FL/PE) projects have increased from 4 in 1970 to 32 in 1990 (17 in French- and Portuguese-speaking Africa and 5 in English-speaking Africa). These projects teach students about the links between demographic problems and socioeconomic factors and contemporary culture. They aim for total development of the individual and improvement of the quality of life for the individual, family, and community. Topics covered in FL/PE are birth rate; fertility; health; and maternal, infant, and child mortality; unwanted pregnancy; illegal abortion; sexually transmitted diseases; rural-urban migration; and urbanization. Benin introduced FL/PE at all levels of its education system while Senegal, Guinea, Mauritania, and Zaire introduced it to only the primary and secondary school levels. Some countries teach FL/PE as one discipline while most countries (e.g., Senegal) have integrated it into other disciplines (e.g., geography). FL/PE should begin in primary schools because they have the most students and prepare students for middle schools, which provide FL/PE. Elementary education in Senegal is being overhauled to introduce current major problems bit by bit. Senegal also wants to incorporate FL/PE into literacy and adult education programs. Integration of FL/PE into other disciplines should be encouraged.

  15. Higher outdoor temperatures are progressively associated with lower blood pressure: a longitudinal study in 100,000 healthy individuals

    NARCIS (Netherlands)

    Hurk, K. van den; Kort, W.L. de; Deinum, J.; Atsma, F.

    2015-01-01

    This study investigated the shape of associations between climate parameters (mean daily temperature and humidity) and systolic and diastolic blood pressure in a large longitudinal cohort of healthy individuals. The study population comprised 101,377 Dutch whole blood and plasma donors (50% men), wh

  16. Longitudinal associations between descriptive and injunctive norms of youngsters and heavy drinking and problem drinking in late adolescence

    NARCIS (Netherlands)

    Voogt, C.V.; Larsen, H.; Poelen, E.A.P.; Kleinjan, M.; Engels, R.C.M.E.

    2013-01-01

    Cross-sectionally, social norms are related to heavy and problem drinking in late adolescence. A better understanding is needed regarding the longitudinal associations between social norms in younger populations and heavy and problem drinking over time. This study distinguished between descriptive (

  17. A Longitudinal Examination of the Psychoeducational, Neurocognitive, and Psychiatric Functioning in Children with 22q11.2 Deletion Syndrome

    Science.gov (United States)

    Hooper, Stephen R.; Curtiss, Kathleen; Schoch, Kelly; Keshavan, Matcheri S.; Allen, Andrew; Shashi, Vandana

    2013-01-01

    The present study sought to examine the longitudinal psychoeducational, neurocognitive, and psychiatric outcomes of children and adolescents with chromosome 22q11.2 deletion syndrome (22q11DS), a population with a high incidence of major psychiatric illnesses appearing in late adolescence/early adulthood. Little is known of the developmental…

  18. Longitudinal Surveys of Australian Youth (LSAY): 1995 Cohort--User Guide. Data Elements A: Demographics. Technical Report 49A

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2012

    2012-01-01

    This technical paper contains information about the variables in the LSAY (Longitudinal Surveys of Australian Youth) Y95 cohort data set. It groups each variable into data elements which identifies common variables within and across waves. Information is provided about each data element including its purpose, values, base populations and relevant…

  19. Consistent Reconstruction of Cortical Surfaces from Longitudinal Brain MR Images

    OpenAIRE

    Li, Gang; Nie, Jingxin; Wu, Guorong; Wang, Yaping; Shen, Dinggang

    2011-01-01

    Accurate and consistent reconstruction of cortical surfaces from longitudinal human brain MR images is of great importance in studying longitudinal subtle change of the cerebral cortex. This paper presents a novel deformable surface method for consistent and accurate reconstruction of inner, central and outer cortical surfaces from longitudinal brain MR images. Specifically, the cortical surfaces of the group-mean image of all aligned longitudinal images of the same subject are first reconstr...

  20. Direct Timing Method for Longitudinal Coordinate Determination in Straws

    OpenAIRE

    Makhankin, A. M.; Myalkovsky, V. V.; Peshekhonov, V. D.; Vasilyev, S. E.

    2013-01-01

    The considering different technics of measuring the longitudinal coordinates by the drift tubes. It is shown that the determination of the longitudinal coordinate by the direct time method provides the best longitudinal resolution. The realization of this method enables the development of coordinate detectors based on the straw with two-dimensional readout, which can be fast enough and not very complex.

  1. Longitudinal analysis of semiconductor lasers with low reflectivity facets

    Energy Technology Data Exchange (ETDEWEB)

    Baets, R.; Lagasse, P.E.; Vande Capelle, J.P.

    1985-06-01

    An analysis is made of longitudinal effects in semiconductor lasers with low facet reflectivities. For this purpose, a self-consistent model is used based on the beam propagation method, which takes into account both the lateral and longitudinal dimension. The calculations show that longitudinal effects have a significant influence on the output fields in the laser.

  2. Health impact: longitudinal analysis of employment at middle and old age in Mexico

    Science.gov (United States)

    GONZÁLEZ-GONZÁLEZ, César; WONG, Rebeca

    2015-01-01

    We use longitudinal data from the Mexican Health and Aging Study to analyze the relationship between health and labor force participation of population aged 50 years and older in Mexico. The results confirm that health, measured through chronic diseases and difficulty to perform activities of daily living, has a powerful influence on labor force participation. We also find important differences by gender; hypertension and diabetes have effects in both, men and women; heart disease and stroke only in men. We provide concrete evidence on economic participation and highlight the importance of public policies to create adequate jobs for the population at middle and old age. PMID:25722646

  3. [Inequalities in mortality in the Italian longitudinal studies].

    Science.gov (United States)

    Cardano, M; Costa, G; Demaria, M; Merler, E; Biggeri, A

    1999-01-01

    The article presents some of the most relevant results on inequalities in mortality, obtained by the two Italian longitudinal studies carried out in Turin, and Tuscany (in Leghorn and Florence). The two studies share the same methodology. Each database contains census data, information from population register and from death certificates. The authors approach this issue not in an analytical way (as they did in the works cited in the reference list), but answering some questions, relevant both from a scientific and a political point of view. How big are the health inequalities in Italy? Are the health inequalities in Italy increasing or decreasing? Are the health inequalities due to absolute or to relative deprivation? Does the mortality profile of the Italian population express the presence of old or new health inequalities? Can the health inequalities be reduced? The study's results prove that the health inequalities in Italy are deep and strictly related to individuals' position in the social fabric. Facing the other questions the authors focus only in the Turin data. From the 1970's to the 1990's the health inequalities in Turin have increased, despite of general improvement of population's health condition and the progressive reduction of the size of deprived groups. Turin data support both the hypotheses on the source of health inequalities, using long term unemployment as absolute deprivation's indicator, and status' inconsistency as (a row) indicator of relative deprivation. The growth of drug-related causes of death (AIDS and overdose) shows that in the Turin and--quite reasonably--Italian population old and new health inequalities live together. The essay closes offering evidence on the possibility to reduce health inequalities. For this purpose the authors analyses the Turin trend of avoidable deaths and infant and adolescent mortality.

  4. A comparison of approaches to estimate the inbreeding coefficient and pairwise relatedness using genomic and pedigree data in a sheep population.

    Directory of Open Access Journals (Sweden)

    Meng-Hua Li

    Full Text Available Genome-wide SNP data provide a powerful tool to estimate pairwise relatedness among individuals and individual inbreeding coefficient. The aim of this study was to compare methods for estimating the two parameters in a Finnsheep population based on genome-wide SNPs and genealogies, separately. This study included ninety-nine Finnsheep in Finland that differed in coat colours (white, black, brown, grey, and black/white spotted and were from a large pedigree comprising 319 119 animals. All the individuals were genotyped with the Illumina Ovine SNP50K BeadChip by the International Sheep Genomics Consortium. We identified three genetic subpopulations that corresponded approximately with the coat colours (grey, white, and black and brown of the sheep. We detected a significant subdivision among the colour types (F(ST = 5.4%, P0.0625 and pairs of closely related animals (e.g. the full- or half-sibs. Nevertheless, we also detected differences in the two parameters between the approaches, particularly with respect to the grey Finnsheep. This could be due to the smaller sample size and relative incompleteness of the pedigree for them.We conclude that the genome-wide genomic data will provide useful information on a per sample or pairwise-samples basis in cases of complex genealogies or in the absence of genealogical data.

  5. LHC Longitudinal Single-Bunch Stability Threshold

    CERN Document Server

    Esteban Muller, Juan Federico; Baudrenghien, Philippe; Lasheen, Alexandre; Roggen, Toon; Shaposhnikova, Elena; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The aim of the MD studies presented here was to determine with a reasonable accuracy the single-bunch longitudinal stability threshold in the LHC. The measurements were performed by placing along the ring 8 or 20 ‘single’ bunches with different intensities but similar longitudinal emittances. Then they were accelerated and bunch stability was observed at arrival to flat top. Combining the results of two measurement sessions, the single bunch stability threshold is estimated to be (2.4 ± 0.2) × 10^11 ppb for an emittance of 1.89 eVs (1.0 ns) at 6.5 TeV with 12 MV RF voltage. Measurements were taken during the MD session MD472 from 22:00 on 20th to 05:00 on 21st July 2015 and session MD365 from 17:00 on 26th to 01:00 on 27th August 2015.

  6. Batch By Batch Longitudinal Emittance Blowup MD

    CERN Document Server

    Mastoridis, T; Butterworth, A; Jaussi, M; Molendijk, J

    2012-01-01

    The transverse bunch emittance increases significantly at 450 GeV from the time of injection till the ramp due to IBS. By selectively blowing up the longitudinal emittance of the incoming batch at each injection, it should be possible to reduce the transverse emittance growth rates due to IBS. An MD was conducted on April 22nd 2012 to test the feasibility and performance of the batch-by-batch longitudinal emittance blowup. There were three main goals during the MD. First, to test the developed hardware, firmware, and software for the batch-by-batch blowup. Then, to measure the transverse emittance growth rates of blown-up and "witness" batches to quantify any improvement, and finally to test the ALLInjectSequencer class, which deals with the complicated gymnastics of introducing or masking the new batch to various RF loops.

  7. Feasibility and reference values of left atrial longitudinal strain imaging by two-dimensional speckle tracking

    Directory of Open Access Journals (Sweden)

    Lisi Matteo

    2009-02-01

    Full Text Available Abstract Background The role of speckle tracking in the assessment of left atrial (LA deformation dynamics is not established. We sought to determine the feasibility and reference ranges of LA longitudinal strain indices measured by speckle tracking in a population of normal subjects. Methods In 60 healthy individuals, peak atrial longitudinal strain (PALS and time to peak longitudinal strain (TPLS were measured using a 12-segment model for the left atrium. Values were obtained by averaging all segments (global PALS and TPLS and by separately averaging segments measured in the two apical views (4- and 2-chamber average PALS and TPLS. Results Adequate tracking quality was achieved in 97% of segments analyzed. Inter and intra-observer variability coefficients of measurements ranged between 2.9% and 5.4%. Global PALS was 42.2 ± 6.1% (5–95° percentile range 32.2–53.2%, and global TPLS was 368 ± 30 ms (5–95° percentile range 323–430 ms. The 2-chamber average PALS was slightly higher than the 4-chamber average PALS (44.3 ± 6.0% vs 40.1 ± 7.9%, p Conclusion Speckle tracking is a feasible technique for the assessment of longitudinal myocardial LA deformation. Reference ranges of strain indices were reported.

  8. CLADA: cortical longitudinal atrophy detection algorithm.

    Science.gov (United States)

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2011-01-01

    Measurement of changes in brain cortical thickness is useful for the assessment of regional gray matter atrophy in neurodegenerative conditions. A new longitudinal method, called CLADA (cortical longitudinal atrophy detection algorithm), has been developed for the measurement of changes in cortical thickness in magnetic resonance images (MRI) acquired over time. CLADA creates a subject-specific cortical model which is longitudinally deformed to match images from individual time points. The algorithm was designed to work reliably for lower resolution images, such as the MRIs with 1×1×5 mm(3) voxels previously acquired for many clinical trials in multiple sclerosis (MS). CLADA was evaluated to determine reproducibility, accuracy, and sensitivity. Scan-rescan variability was 0.45% for images with 1mm(3) isotropic voxels and 0.77% for images with 1×1×5 mm(3) voxels. The mean absolute accuracy error was 0.43 mm, as determined by comparison of CLADA measurements to cortical thickness measured directly in post-mortem tissue. CLADA's sensitivity for correctly detecting at least 0.1mm change was 86% in a simulation study. A comparison to FreeSurfer showed good agreement (Pearson correlation=0.73 for global mean thickness). CLADA was also applied to MRIs acquired over 18 months in secondary progressive MS patients who were imaged at two different resolutions. Cortical thinning was detected in this group in both the lower and higher resolution images. CLADA detected a higher rate of cortical thinning in MS patients compared to healthy controls over 2 years. These results show that CLADA can be used for reliable measurement of cortical atrophy in longitudinal studies, even in lower resolution images.

  9. Longitudinal matching between SFC and SSC

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Q.M.; Tang, J.Y.; Wang, S.L. [Institute of Modern Physics, China Academy of Science, Lanzhou (China)

    1998-11-01

    In order to increase the beam current and to enhance the beam quality, an upgrading program of HIRFL is going on at HIRFL. As a part of this program, the longitudinal matching between injector SFC and main machine SSC will be improved. It consists of beam energy measurement, compensation of energy loss due to stripper and a new rebuncher system. In this paper, the study results are presented. (author)

  10. Renormalization of QCD under longitudinal rescaling

    CERN Document Server

    Xiao, Jing

    2009-01-01

    The form of the quantum Yang-Mills action, under a longitudinal rescaling is determined using a Wilsonian renormalization group. The high-energy limit, is the extreme limit of such a rescaling. We compute the anomalous dimensions and discuss the validity of the high-energy limit. This thesis is an expanded version of joint work with P. Orland, which appeared in arXiv:0901.2955.

  11. Marginal longitudinal semiparametric regression via penalized splines

    KAUST Repository

    Al Kadiri, M.

    2010-08-01

    We study the marginal longitudinal nonparametric regression problem and some of its semiparametric extensions. We point out that, while several elaborate proposals for efficient estimation have been proposed, a relative simple and straightforward one, based on penalized splines, has not. After describing our approach, we then explain how Gibbs sampling and the BUGS software can be used to achieve quick and effective implementation. Illustrations are provided for nonparametric regression and additive models.

  12. Transmission of Information by Longitudinal Electromagnetic Waves

    CERN Document Server

    Barashenkov, V S; Yuriev, M Z

    2001-01-01

    In Maxwell electrodynamics longitudinal wave irradiation is strongly forbidden by the so-called gauge invariance. However, these waves are present in virtual quantum processes and they can be used to transfer information at macroscopic distances by the displacement of the interference picture due to the change of the phase of electron wave function. The transmission can be carried out so that it will be hidden for usual observation.

  13. Space Charge Mitigation With Longitudinally Hollow Bunches

    CERN Document Server

    Oeftiger, Adrian; Rumolo, Giovanni; CERN. Geneva. ATS Department

    2016-01-01

    Suitably, hollow longitudinal phase space distributions have a flat profile and hence reduce the impact of transverse space charge. Dipolar parametric excitation with the phase loop feedback systems provides such hollow distributions under reproducible conditions. We present a procedure to create hollow bunches during the acceleration ramp of CERN’s PS Booster machine with minimal changes to the operational cycle. The improvements during the injection plateau of the downstream Proton Synchrotron are assessed in comparison to standard parabolic bunches.

  14. Marginal longitudinal semiparametric regression via penalized splines.

    Science.gov (United States)

    Kadiri, M Al; Carroll, R J; Wand, M P

    2010-08-01

    We study the marginal longitudinal nonparametric regression problem and some of its semiparametric extensions. We point out that, while several elaborate proposals for efficient estimation have been proposed, a relative simple and straightforward one, based on penalized splines, has not. After describing our approach, we then explain how Gibbs sampling and the BUGS software can be used to achieve quick and effective implementation. Illustrations are provided for nonparametric regression and additive models.

  15. Space Charge Mitigation With Longitudinally Hollow Bunches

    CERN Multimedia

    Oeftiger, Adrian; Rumolo, Giovanni

    2016-01-01

    Hollow longitudinal phase space distributions have a flat profile and hence reduce the impact of transverse space charge. Dipolar parametric excitation with the phase loop feedback systems provides such hollow distributions under reproducible conditions. We present a procedure to create hollow bunches during the acceleration ramp of CERN’s PS Booster machine with minimal changes to the operational cycle. The improvements during the injection plateau of the downstream Proton Synchrotron are assessed in comparison to standard parabolic bunches.

  16. Forbidden fruit? A longitudinal study of Christianity, sex, and marriage.

    Science.gov (United States)

    Pedersen, Willy

    2014-01-01

    Does religion still play a role in explorations of romance and sexuality among adolescents and young adults in a secular society such as Norway? Does it influence the type of living arrangements chosen? A population-based sample (n = 2,454) was followed longitudinally from their midteens to their late 20s using survey and register data. Christian involvement in teenage years was associated with subsequent less "precoital" exploration, less masturbation, delayed sexual intercourse, and a smaller number of sex partners. However, there were no associations with prevalence of same-sex experiences. Christians also postponed initiating romantic relationships and chose marriage over cohabitation. Associations were reduced after controlling for confounding factors but remained significant. Some associations (for example, the form of residential union chosen) were present only in the most "active" Christians. In other areas, such as "precoital explorations" and the age at which intercourse is initiated, Christian norms seem to play a role in much broader segments of the population. The findings indicate that Christianity may continue to influence young Norwegians' experiences of sexuality and cohabitation more than has been expected.

  17. Population dynamics

    Directory of Open Access Journals (Sweden)

    Cooch, E. G.

    2004-06-01

    Full Text Available Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population minus the number of subtractions (individuals leaving the population. Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996, and factors influencing those dynamics (e.g., Nichols et al., 2000. The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004. Caswell notes that although interest has traditionally

  18. Multilevel Cross-Dependent Binary Longitudinal Data

    KAUST Repository

    Serban, Nicoleta

    2013-10-16

    We provide insights into new methodology for the analysis of multilevel binary data observed longitudinally, when the repeated longitudinal measurements are correlated. The proposed model is logistic functional regression conditioned on three latent processes describing the within- and between-variability, and describing the cross-dependence of the repeated longitudinal measurements. We estimate the model components without employing mixed-effects modeling but assuming an approximation to the logistic link function. The primary objectives of this article are to highlight the challenges in the estimation of the model components, to compare two approximations to the logistic regression function, linear and exponential, and to discuss their advantages and limitations. The linear approximation is computationally efficient whereas the exponential approximation applies for rare events functional data. Our methods are inspired by and applied to a scientific experiment on spectral backscatter from long range infrared light detection and ranging (LIDAR) data. The models are general and relevant to many new binary functional data sets, with or without dependence between repeated functional measurements.

  19. Longitudinal development of a substorm brightening arc

    Directory of Open Access Journals (Sweden)

    K. Shiokawa

    2009-05-01

    Full Text Available We present simultaneous THEMIS-ground observations of longitudinal (eastward extension of a substorm initial-brightening arc at Gillam (magnetic latitude: 65.6° at 08:13 UT on 10 January 2008. The speed of the eastward arc extension was ~2.7 km/s. The extension took place very close to the footprints of the longitudinally separated THEMIS E and D satellites at ~12 RE. The THEMIS satellites observed field dipolarization, weak earthward flow, and pressure increase, which propagated eastward from E to D at a speed of ~50 km/s. The THEMIS A satellite, located at 1.6 RE earthward of THEMIS E, observed fluctuating magnetic field during and after the dipolarization. The THEMIS E/D observations suggest that the longitudinal extension of the brightening arc at substorm onset is caused by earthward flow braking processes which produce field dipolarization and pressure increase propagating in longitude in the near-earth plasma sheet.

  20. Stellar Populations

    NARCIS (Netherlands)

    Peletier, Reynier F.

    2013-01-01

    This is a summary of my lectures during the 2011 Canary Islands Winter School in Puerto de la Cruz. I give an introduction to the field of stellar populations in galaxies, and highlight some new results. Since the title of the Winter School is Secular Evolution in Galaxies I mostly concentrate on ne

  1. The Impact of Neighborhood Disadvantage on the Black-White Achievement Gap

    Science.gov (United States)

    Lee, Moosung; Madyun, Na'im

    2009-01-01

    Contextual analysis of the achievement gap has gained much momentum within the last few decades. This study furthers the discourse by examining the applicability of 2 sociological contextual development approaches on achievement. We analyzed 79 neighborhoods organized by the level of crime and poverty from both a social disorganization and social…

  2. Race in Buenos Aires. Blackness, Whiteness, African Descent and Mestizaje in the White Capital City

    Directory of Open Access Journals (Sweden)

    Lea Geler

    2016-03-01

    Full Text Available This article analyzes how racial categories are produced and reproduced in Buenos Aires, Argentina’s capital city. To that end, this article focuses on the cases of three Afro-Descendant porteña women who, by local standards, are fully white.  Their stories allow us to explore, in the first place, how categories like “black,” “white,” and others are used and understood in contemporary Buenos Aires and how this use configures two types of blackness (racial blackness and popular blackness and makes it impossible for mestizaje categories to emerge. In the second place, through these cases this article explores how people’s very “ways of being” are at play, creating a discriminatory and oppressive environment for people at risk of not matching the ideal of the nation.

  3. 1995 - Black & White - Addi, Frank, Grand, Lam, Wash (0.5m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VTORTHO_0_5M_PAN_1995 data includes panchromatic (black and white) orthophotography (orthophoto) at 1:5000 scale (0.5 meter cell resolution)....

  4. The Quality of Education and Cohort Variation in Black-White Earnings Differentials: Reply.

    Science.gov (United States)

    Welch, Finis

    1980-01-01

    Examines the methodology used by the authors of the article immediately preceding this one. Questions both the use of expenditure per student as a measure of educational quality and the cohort effect's influence on the differences in the wage earnings of Blacks and Whites. Available from American Economic Review, 1313 21st Avenue So., Suite 809,…

  5. The Quality of Education and Cohort Variation in Black-White Earnings Differentials: Comment.

    Science.gov (United States)

    Akin, John S.; Garfinkel, Irv

    1980-01-01

    Even after controlling for quality, ability, and motivation, a large difference in predicted earnings for Whites and Blacks was found. The returns to years of education for Whites are approximately three percentage points greater than for Blacks at every working age. Available from American Economic Review, 1313 21st Avenue So., Suite 809,…

  6. An Exploratory Study of Socialization Effects on Black Children: Some Black-White Comparisons

    Science.gov (United States)

    Baumrind, Diana

    1972-01-01

    Major conclusion from this exploratory analysis was that if the black families were viewed by white norms they appeared authoritarian, but that, unlike their white counterparts, the most authoritarian of these families produced the most self-assertive and independent girls. (Author)

  7. Black, white or green: 'race', gender and avatars within the therapeutic space.

    Science.gov (United States)

    Graber, Mark A; Graber, Abraham D

    2011-06-01

    Personal identity is critical to provider--patient interactions. Patients and doctors tend to self-select, ideally forming therapeutic units that maximise the patients' benefit. Recently, however, 'reality' has changed. The internet and virtual worlds such as Second Life (http://www.secondlife.com/) allow models of identity and provider--patient interactions that go beyond the limits of mainstream personal identity. In this paper some of the ethical implications of virtual patient--provider interactions, especially those that have to do with personal identity, are explored.

  8. Estimating Counterfactual Densities: An application to Black-White Wage Differentials in the U.S.

    OpenAIRE

    Donal O'Neill; Olive Sweetman; Dirk Van de Gaer

    2000-01-01

    In this paper we use a semi-parmaetric procedure developed by DiNardo et al(1996),to examine the distribution of the racial wage gap in the U.S and to examine the extent to which forces underlying this wage gap vary throughout the distribution. In carrying out our analyses, we focus on recent work by Neal and Johnson who argue that one test score explains much of the average racial wage gap for men. Our resutls show that the wage differential varies significantly throughout the distribution F...

  9. Affirmative Action, Incentives and the Black-White Test Score Gap

    OpenAIRE

    2004-01-01

    This paper develops a theoretical model of college admissions to study the effects of affirmative action policies on the high school achievement of college bound students. The innovation is to include endogenous human capital decisions in the model. When colleges switch admissions policies, they implicitly alter the likelihood of acceptance earned by a given human capital investment. Thus, human capital investments are sensitive to changes in admissions policies. The main results are that ban...

  10. A Black (White) Hole in the Global Spread of GM Cotton.

    Science.gov (United States)

    Burkitbayeva, Saule; Qaim, Matin; Swinnen, Johan

    2016-04-01

    Bt (Bacillus thuringiensis) cotton has been widely adopted, notably by smallholder farmers in developing countries. However, it has not been used in Central Asia, an important cotton-producing region. We discuss possible reasons and hypothesize that the most likely explanation is limited local demand for Bt owing to low levels of pest infestation. This would imply that global Bt cotton adoption rates may already be close to 100% when considering real demand for insect-resistant varieties.

  11. MODELING BLACK-WHITE PRETERM BIRTH DISPARITY: ECOLOGIC AND MULTILEVEL MODELS

    Science.gov (United States)

    INTRODUCTION. The disparity between black and white women's adverse birth outcomes has been subject to much investigation, yet the factors underlying its persistence remain elusive, which has encouraged research on neighborhood-level influences. This work considers two main que...

  12. Stickleback Population

    Directory of Open Access Journals (Sweden)

    Ulrika Candolin

    2012-01-01

    Full Text Available Human-induced eutrophication has increased offspring production in a population of threespine stickleback Gasterosteus aculeatus in the Baltic Sea. Here, we experimentally investigated the effects of an increased density of juveniles on behaviours that influence survival and dispersal, and, hence, population growth—habitat choice, risk taking, and foraging rate. Juveniles were allowed to choose between two habitats that differed in structural complexity, in the absence and presence of predators and conspecific juveniles. In the absence of predators or conspecifics, juveniles preferred the more complex habitat. The preference was further enhanced in the presence of a natural predator, a perch Perca fluviatilis (behind a transparent Plexiglas wall. However, an increased density of conspecifics relaxed the predator-enhanced preference for the complex habitat and increased the use of the open, more predator-exposed habitat. Foraging rate was reduced under increased perceived predation risk. These results suggest that density-dependent behaviours can cause individuals to choose suboptimal habitats where predation risk is high and foraging rate low. This could contribute to the regulation of population growth in eutrophicated areas where offspring production is high.

  13. Population aging.

    Science.gov (United States)

    1999-04-01

    This paper focuses on the impact of population aging in China, the most densely populated country in the world. Statistics indicate that by the end of 1998, 83.75 million out of the 1.248 billion Chinese people will be over 65 years old. According to the UN standards, China will soon become an aging society. The aging population poses several challenges to the country with the greatest challenge being the increasing social responsibility to care for the aged. With the undeveloped legislative framework to protect the interests of the aged and the serious drawbacks in the pension system to cater only to the income part and not the service part of the aged, China is not yet ready for the advent of aging. Violation of the rights of senior citizens is still very rampant despite enactment of the law on Protection of the Rights of the Elderly in 1996. Moreover, China is not economically ready to become an aging society. China faces this challenge by adopting a three-pronged approach to solve the problem namely: family support, establishment of nursing homes, and creating a social security framework that addresses the needs of the society suited to the Chinese condition. It is believed that with the growing economy of the country and the rising income of its people, a comprehensive social security net will be created to take care of the aged.

  14. Longitudinal evaluation of leukocyte transcripts in killer whales (Orcinus Orca)

    Science.gov (United States)

    Sitt, Tatjana; Bowen, Lizabeth; Lee, Chia-Shan; Blanchard, Myra; McBain, James; Dold, Christopher; Stott, Jeffrey L.

    2016-01-01

    Early identification of illness and/or presence of environmental and/or social stressors in free-ranging and domestic cetaceans is a priority for marine mammal health care professionals. Incorporation of leukocyte gene transcript analysis into the diagnostic tool kit has the potential to augment classical diagnostics based upon ease of sample storage and shipment, inducible nature and well-defined roles of transcription and associated downstream actions. Development of biomarkers that could serve to identify “insults” and potentially differentiate disease etiology would be of great diagnostic value. To this end, a modest number of peripheral blood leukocyte gene transcripts were selected for application to a domestic killer whale population with a focus on broad representation of inducible immunologically relevant genes. Normalized leukocyte transcript values, longitudinally acquired from 232 blood samples derived from 26 clinically healthy whales, were not visibly influenced temporally nor by sex or the specific Park in which they resided. Stability in leukocyte transcript number during periods of health enhances their potential use in diagnostics through identification of outliers. Transcript levels of two cytokine genes, IL-4 and IL-17, were highly variable within the group as compared to the other transcripts. IL-4 transcripts were typically absent. Analysis of transcript levels on the other genes of interest, on an individual animal basis, identified more outliers than were visible when analyzed in the context of the entire population. The majority of outliers (9 samples) were low, though elevated transcripts were identified for IL-17 from 2 animals and one each for Cox-2 and IL-10. The low number of outliers was not unexpected as sample selection was intentionally directed towards animals that were clinically healthy at the time of collection. Outliers may reflect animals experiencing subclinical disease that is transient and self-limiting. The

  15. Longitudinal evaluation of leukocyte transcripts in killer whales (Orcinus Orca).

    Science.gov (United States)

    Sitt, Tatjana; Bowen, Lizabeth; Lee, Chia-Shan; Blanchard, Myra T; McBain, James; Dold, Christopher; Stott, Jeffrey L

    2016-07-01

    Early identification of illness and/or presence of environmental and/or social stressors in free-ranging and domestic cetaceans is a priority for marine mammal health care professionals. Incorporation of leukocyte gene transcript analysis into the diagnostic tool kit has the potential to augment classical diagnostics based upon ease of sample storage and shipment, inducible nature and well-defined roles of transcription and associated downstream actions. Development of biomarkers that could serve to identify "insults" and potentially differentiate disease etiology would be of great diagnostic value. To this end, a modest number of peripheral blood leukocyte gene transcripts were selected for application to a domestic killer whale population with a focus on broad representation of inducible immunologically relevant genes. Normalized leukocyte transcript values, longitudinally acquired from 232 blood samples derived from 26 clinically healthy whales, were not visibly influenced temporally nor by sex or the specific Park in which they resided. Stability in leukocyte transcript number during periods of health enhances their potential use in diagnostics through identification of outliers. Transcript levels of two cytokine genes, IL-4 and IL-17, were highly variable within the group as compared to the other transcripts. IL-4 transcripts were typically absent. Analysis of transcript levels on the other genes of interest, on an individual animal basis, identified more outliers than were visible when analyzed in the context of the entire population. The majority of outliers (9 samples) were low, though elevated transcripts were identified for IL-17 from 2 animals and one each for Cox-2 and IL-10. The low number of outliers was not unexpected as sample selection was intentionally directed towards animals that were clinically healthy at the time of collection. Outliers may reflect animals experiencing subclinical disease that is transient and self-limiting. The immunologic

  16. The USA National Longitudinal Lesbian Family Study (NLLFS): homophobia, psychological adjustment, and protective factors.

    Science.gov (United States)

    Bos, Henny M W; Gartrell, Nanette K; Peyser, Heidi; van Balen, Frank

    2008-01-01

    The study assessed the influence of protective factors on the psychological adjustment of children who had experienced homophobia and whose mothers were participants in a longitudinal study of planned lesbian families. Data were collected as part of the National Longitudinal Lesbian Family Study by interviewing the children and having the mothers complete questionnaires. No significant differences were found in the psychological adjustment of children in the present study and their age-matched peers in a U.S.-population sample. Homophobia had a negative impact on the well-being of children who experienced it. Attending schools with LGBT curricula and their mothers' participation in the lesbian community were found to protect children against the negative influences of homophobia.

  17. Longitudinal Receptive American Sign Language Skills Across a Diverse Deaf Student Body.

    Science.gov (United States)

    Beal-Alvarez, Jennifer S

    2016-04-01

    This article presents results of a longitudinal study of receptive American Sign Language (ASL) skills for a large portion of the student body at a residential school for the deaf across four consecutive years. Scores were analyzed by age, gender, parental hearing status, years attending the residential school, and presence of a disability (i.e., deaf with a disability). Years 1 through 4 included the ASL Receptive Skills Test (ASL-RST); Years 2 through 4 also included the Receptive Test of ASL (RT-ASL). Student performance for both measures positively correlated with age; deaf students with deaf parents scored higher than their same-age peers with hearing parents in some instances but not others; and those with a documented disability tended to score lower than their peers without disabilities. These results provide longitudinal findings across a diverse segment of the deaf/hard of hearing residential school population.

  18. Delineation of concentration ranges and longitudinal changes of human plasma protein variants.

    Directory of Open Access Journals (Sweden)

    Olgica Trenchevska

    Full Text Available Human protein diversity arises as a result of alternative splicing, single nucleotide polymorphisms (SNPs and posttranslational modifications. Because of these processes, each protein can exists as multiple variants in vivo. Tailored strategies are needed to study these protein variants and understand their role in health and disease. In this work we utilized quantitative mass spectrometric immunoassays to determine the protein variants concentration of beta-2-microglobulin, cystatin C, retinol binding protein, and transthyretin, in a population of 500 healthy individuals. Additionally, we determined the longitudinal concentration changes for the protein variants from four individuals over a 6 month period. Along with the native forms of the four proteins, 13 posttranslationally modified variants and 7 SNP-derived variants were detected and their concentration determined. Correlations of the variants concentration with geographical origin, gender, and age of the individuals were also examined. This work represents an important step toward building a catalog of protein variants concentrations and examining their longitudinal changes.

  19. A gender-based dynamic multidimensional longitudinal analysis of resilience and mortality in the old-old in Israel: the cross-sectional and longitudinal aging study (CALAS).

    Science.gov (United States)

    Walter-Ginzburg, Adrian; Shmotkin, Dov; Blumstein, Tzvia; Shorek, Aviva

    2005-04-01

    The objective was to examine gender differences and similarities in health, function, familial and non-familial social networks; longitudinal resilience in those factors; and their association with risk of mortality in Israeli men and women aged 75-94. We used the Cross-Sectional and Longitudinal Aging Study (CALAS), a stratified random sample of 960 Israeli Jews aged 75-94, drawn on January 1, 1989 from National Population Registry, stratified by gender, age (75-79, 80-84, 85-89, 90-94), and place of birth (Europe/America, Middle East/North Africa, Israel), interviewed twice (Wave 1, 1989-1992; Wave 2, 1993-1995); Wave 1 values and longitudinal resilience predicted the 1999 mortality risk for those alive at both waves. Gender differences and similarities were found at Wave 1 in longitudinal resilience and in risk factors for mortality, partially supporting a gender paradox. Men were more physically active, had better cognition, gave more help to children, relied less on paid caretakers, and attended synagogue more than women, factors associated with better health and functioning. Women had poorer health and functional status and more help from children. More physical activity, synagogue attendance, and resilience in activities of daily living (ADL) were associated with lower risk of mortality for both genders. Women's risk of mortality was reduced by smoking reduction and higher cognitive vitality, and men's by emotional support and solitary leisure activity. Both men and women were resilient, yet there were differences. Gender-neutral mortality reduction programs would include physical activity, religious services, maintenance and improvement of ADL, and engaging in solitary leisure activities; for women, smoking cessation and cognitively challenging activities; and for men, maintaining or increasing emotional ties.

  20. Resonant longitudinal Zitterbewegung in zigzag graphene nanoribbons

    KAUST Repository

    Ghosh, S.

    2015-01-08

    The Zitterbewegung of a wave packet in a zigzag graphene nanoribbon is theoretically investigated. The coupling between edge states and bulk states results in intriguing properties. Apart from the oscillation in position perpendicular to the direction of motion, we also observe an oscillation along the direction of propagation which is not present in semiconductor nanowires or infinite graphene sheets. We also observe a resonance of its amplitude with respect to the central momentum of the wave packet. We show here that this longitudinal Zitterbewegung is caused by the interplay between bulk and edge states, which is a unique property of a zigzag nanoribbon.

  1. Fracture structure near a longitudinal shear macrorupture

    Science.gov (United States)

    Goldstein, R. V.; Osipenko, N. M.

    2012-09-01

    Fracture evolution the near a main longitudinal shear in the presence of normal stresses is studied. Experiments with model materials (gypsum, cheese) showed that a multiscale echelon structure of cracks feathering the main rupture is formed under the shear domination conditions. A system of small cracks in the initial echelon is replaced by an echelon of larger and sparser cracks. Intensive transverse compression along the normal to the shear plane, which imitates the initial stress concentrator, takes the fracture region away from the shear plane. A model of evolution development of the observed echelon structure along the main rupture front under the shear domination conditions is proposed.

  2. Modeling local dependence in longitudinal IRT models

    DEFF Research Database (Denmark)

    Larsen, Maja Olsbjerg; Christensen, Karl Bang

    2015-01-01

    Measuring change in a latent variable over time is often done using the same instrument at several time points. This can lead to dependence between responses across time points for the same person yielding within person correlations that are stronger than what can be attributed to the latent...... variable. Ignoring this can lead to biased estimates of changes in the latent variable. In this paper we propose a method for modeling local dependence in the longitudinal 2PL model. It is based on the concept of item splitting, and makes it possible to correctly estimate change in the latent variable....

  3. Longitudinal Viscous Flow in Granular Gases

    OpenAIRE

    Santos, Andres

    2008-01-01

    The flow characterized by a linear longitudinal velocity field $u_x(x,t)=a(t)x$, where $a(t)={a_0}/({1+a_0t})$, a uniform density $n(t)\\propto a(t)$, and a uniform temperature $T(t)$ is analyzed for dilute granular gases by means of a BGK-like model kinetic equation in $d$ dimensions. For a given value of the coefficient of normal restitution $\\alpha$, the relevant control parameter of the problem is the reduced deformation rate $a^*(t)=a(t)/\

  4. Regional vulnerability of longitudinal cortical association connectivity

    Directory of Open Access Journals (Sweden)

    Rafael Ceschin

    2015-01-01

    Full Text Available Preterm born children with spastic diplegia type of cerebral palsy and white matter injury or periventricular leukomalacia (PVL, are known to have motor, visual and cognitive impairments. Most diffusion tensor imaging (DTI studies performed in this group have demonstrated widespread abnormalities using averaged deterministic tractography and voxel-based DTI measurements. Little is known about structural network correlates of white matter topography and reorganization in preterm cerebral palsy, despite the availability of new therapies and the need for brain imaging biomarkers. Here, we combined novel post-processing methodology of probabilistic tractography data in this preterm cohort to improve spatial and regional delineation of longitudinal cortical association tract abnormalities using an along-tract approach, and compared these data to structural DTI cortical network topology analysis. DTI images were acquired on 16 preterm children with cerebral palsy (mean age 5.6 ± 4 and 75 healthy controls (mean age 5.7 ± 3.4. Despite mean tract analysis, Tract-Based Spatial Statistics (TBSS and voxel-based morphometry (VBM demonstrating diffusely reduced fractional anisotropy (FA reduction in all white matter tracts, the along-tract analysis improved the detection of regional tract vulnerability. The along-tract map-structural network topology correlates revealed two associations: (1 reduced regional posterior–anterior gradient in FA of the longitudinal visual cortical association tracts (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiation, posterior thalamic radiation correlated with reduced posterior–anterior gradient of intra-regional (nodal efficiency metrics with relative sparing of frontal and temporal regions; and (2 reduced regional FA within frontal–thalamic–striatal white matter pathways (anterior limb/anterior thalamic radiation, superior longitudinal fasciculus and cortical spinal tract

  5. Latitudinal and longitudinal clines of phenotypic plasticity in the invasive herb Solidago canadensis in China.

    Science.gov (United States)

    Li, Junmin; Du, Leshan; Guan, Wenbin; Yu, Fei-Hai; van Kleunen, Mark

    2016-11-01

    Phenotypic plasticity is thought to be important for plants in variable environments. The climatic variability hypothesis poses that populations at higher latitudes, due to the stronger variation in temperature, there should be more plastic in response to temperature than populations at lower latitudes. Similarly, populations at locations with stronger precipitation fluctuations should be more plastic in response to water availability than populations at locations with less variable precipitation. We sampled seven and nine populations of Solidago canadensis, a North American native that is invasive in China, along a latitudinal (temperature variability) and a longitudinal (precipitation variability) gradient, respectively, in China, and grew them under two temperature treatments and two water-availability treatments, respectively. Among the four traits with significant variation in plasticity among populations in response to temperature, plasticity of leaf length-to-width ratio was significantly positively correlated with latitude and temperature seasonality of the populations. In addition, root/shoot ratio and water-use efficiency showed significant variation in plasticity among populations in response to water availability, and plasticities of these two traits were significantly negatively correlated with longitude and positively correlated with precipitation seasonality. The observed geographic clines in plasticity suggest that phenotypic plasticity of S. canadensis may have evolved rapidly in regions with different climatic conditions, and this may have contributed to the spread of this invasive species.

  6. Obsessive-Compulsive Disorder, Psychosis, and Bipolarity: A Longitudinal Cohort and Multigenerational Family Study.

    Science.gov (United States)

    Cederlöf, Martin; Lichtenstein, Paul; Larsson, Henrik; Boman, Marcus; Rück, Christian; Landén, Mikael; Mataix-Cols, David

    2015-09-01

    Obsessive-compulsive disorder (OCD) often co-occurs with psychotic and bipolar disorders; this comorbidity complicates the clinical management of these conditions. In this population-based longitudinal and multigenerational family study, we examined the patterns of comorbidity, longitudinal risks, and shared familial risks between these disorders. Participants were individuals with a diagnosis of OCD (n = 19,814), schizophrenia (n = 58,336), bipolar disorder (n = 48,180), and schizoaffective disorder (n = 14,904) included in the Swedish Patient Register between January 1969 and December 2009; their first-, second-, and third-degree relatives; and population-matched (1:10 ratio) unaffected comparison individuals and their relatives. The Swedish Prescribed Drug Register was used to control for the potential effect of medication in the longitudinal analyses. Individuals with OCD had a 12-fold increased risk of having a comorbid diagnosis of schizophrenia and a 13-fold increased risk of bipolar disorder and schizoaffective disorder. Longitudinal analyses showed that individuals first diagnosed with OCD had an increased risk for later diagnosis of all other disorders, and vice versa. The risk of bipolar disorder was reduced, but not eliminated, when the use of selective serotonin reuptake inhibitors was adjusted for. OCD-unaffected first-, second-, and third-degree relatives of probands with OCD had a significantly increased risk for all 3 disorders; the magnitude of this risk decreased as the genetic distance increased. We conclude that OCD is etiologically related to both schizophrenia spectrum and bipolar disorders. The results have implications for current gene-searching efforts and for clinical practice.

  7. Indian populations

    CERN Document Server

    Spahni,J

    1974-01-01

    Le Prof. J.C. Spahni qui a parcouru les Andes, Vénezuela etc. parle de ses expériences et connaissances qu'il a vécu au cours des 14 ans parmi les populations indiennes de la Cordillière des Andes. Il a ramené des objets artisanals indiens lesquels l'auditoire peut acquérir. L'introduction-conférence est suivi d'un film, commenté par lui-même; après l'entracte il y un débat-dialogue avec le public.

  8. Crash and rebound of indigenous populations in lowland South America

    Science.gov (United States)

    Hamilton, Marcus J.; Walker, Robert S.; Kesler, Dylan C.

    2014-04-01

    Lowland South America has long been a battle-ground between European colonization and indigenous survival. Initial waves of European colonization brought disease epidemics, slavery, and violence that had catastrophic impacts on indigenous cultures. In this paper we focus on the demography of 238 surviving populations in Brazil. We use longitudinal censuses from all known indigenous Brazilian societies to quantify three demographic metrics: 1) effects of European contact on indigenous populations; 2) empirical estimates of minimum viable population sizes; and 3) estimates of post-contact population growth rates. We use this information to conduct population viability analysis (PVA). Our results show that all surviving populations suffered extensive mortality during, and shortly after, contact. However, most surviving populations exhibit positive growth rates within the first decade post-contact. Our findings paint a positive demographic outlook for these indigenous populations, though long-term survival remains subject to powerful externalities, including politics, economics, and the pervasive illegal exploitation of indigenous lands.

  9. Longitudinal Studies of Attitude Change: Issues and Methods

    Science.gov (United States)

    1975-04-01

    relative contributions of variables which are presently influencing attitudes from historical variables. Conversely a longitudinal method can be used to...different training techniques. Neidt and Meredith (1966) used a longitudinal method to determine the changes in attitudes of a single group of Air... longitudinal method is viewed as the most promising for measurement of change. With the increasing improvement in unobtrusive measures (e.g., Webb

  10. Consistent Reconstruction of Cortical Surfaces from Longitudinal Brain MR Images

    OpenAIRE

    Li, Gang; Nie, Jingxin; Shen, Dinggang

    2011-01-01

    Accurate and consistent reconstruction of cortical surfaces from longitudinal human brain MR images is of great importance in studying subtle morphological changes of the cerebral cortex. This paper presents a new deformable surface method for consistent and accurate reconstruction of inner, central and outer cortical surfaces from longitudinal MR images. Specifically, the cortical surfaces of the group-mean image of all aligned longitudinal images of the same subject are first reconstructed ...

  11. Longitudinal data analysis a handbook of modern statistical methods

    CERN Document Server

    Fitzmaurice, Garrett; Verbeke, Geert; Molenberghs, Geert

    2008-01-01

    Although many books currently available describe statistical models and methods for analyzing longitudinal data, they do not highlight connections between various research threads in the statistical literature. Responding to this void, Longitudinal Data Analysis provides a clear, comprehensive, and unified overview of state-of-the-art theory and applications. It also focuses on the assorted challenges that arise in analyzing longitudinal data. After discussing historical aspects, leading researchers explore four broad themes: parametric modeling, nonparametric and semiparametric methods, joint

  12. Effectiveness of emergency medicine in longitudinal integrated clerkships

    OpenAIRE

    Banh, Kenny; Ramirez, Rene; Thabit, Christina

    2014-01-01

    Objective: This study investigated third-year students’ experience with the emergency medicine (EM) component in integrated longitudinal programs. The study aimed to see if EM could be integrated into third-year integrated longitudinal programs while addressing accreditation standards and increasing interest in EM.Methods: The authors surveyed students who participated in an integrated longitudinal program at University of California San Francisco School of Medicine (UCSF) from 2010 to 2012. ...

  13. EXPERIMENTAL INVESTIGATIONS ON LONGITUDINAL DISPERSION CHARACTERISTICS OF TIDAL RIVERS

    Institute of Scientific and Technical Information of China (English)

    Fan Jing-yu; Wang Dao-zeng; Zhong Bao-chang

    2003-01-01

    The longitudinal dispersion characteristics of tidal rivers are experimentally investigated in a water channel. The longitudinal dispersion features and influential factors on pollutant in various stages of a tidal period in natural rivers are studied, the value ranges and variation trends of the longitudinal dispersion coefficient are obtained by means of concentration measurement. The results can provide important parameters for establishing the water quality mathematical models in tidal rivers.

  14. Longitudinal Muscle Dysfunction in Achalasia Esophagus and Its Relevance

    OpenAIRE

    Mittal, Ravinder K.; Hong, Su Jin; Bhargava, Valmik

    2013-01-01

    Muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. Goal of this review is to summarize the role of longitudinal muscle in physiology and pathophysiology of esophageal sensory and motor function. Simultaneous manometry and ultrasound imaging that measure circular and longitudinal muscle contraction respectively reveal that during peristalsis 2 layers of the esophagus contract in perfect synchrony. On the other hand, during transient relaxation of the...

  15. Tunable Mechanical Filter for Longitudinal Vibrations

    Directory of Open Access Journals (Sweden)

    S. Asiri

    2007-01-01

    Full Text Available This paper presents both theoretically and experimentally a new kind of vibration isolator called tunable mechanical filter which consists of four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a filter, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the “Pass Bands” and wave propagation is efficiently attenuated within other frequency bands called the “Stop Bands”. The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. The concept of this mechanical filter as presented can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

  16. Multivariate Longitudinal Analysis with Bivariate Correlation Test

    Science.gov (United States)

    Adjakossa, Eric Houngla; Sadissou, Ibrahim; Hounkonnou, Mahouton Norbert; Nuel, Gregory

    2016-01-01

    In the context of multivariate multilevel data analysis, this paper focuses on the multivariate linear mixed-effects model, including all the correlations between the random effects when the dimensional residual terms are assumed uncorrelated. Using the EM algorithm, we suggest more general expressions of the model’s parameters estimators. These estimators can be used in the framework of the multivariate longitudinal data analysis as well as in the more general context of the analysis of multivariate multilevel data. By using a likelihood ratio test, we test the significance of the correlations between the random effects of two dependent variables of the model, in order to investigate whether or not it is useful to model these dependent variables jointly. Simulation studies are done to assess both the parameter recovery performance of the EM estimators and the power of the test. Using two empirical data sets which are of longitudinal multivariate type and multivariate multilevel type, respectively, the usefulness of the test is illustrated. PMID:27537692

  17. Splinting of Longitudinal Fracture: An Innovative Approach

    Directory of Open Access Journals (Sweden)

    Rashmi Bansal

    2016-01-01

    Full Text Available Trauma may result in craze lines on the enamel surface, one or more fractured cusps of posterior teeth, cracked tooth syndrome, splitting of posterior teeth, and vertical fracture of root. Out of these, management of some fractures is of great challenge and such teeth are generally recommended for extraction. Literature search reveals attempts to manage such fractures by full cast crown, orthodontic wires, and so forth, in which consideration was given to extracoronal splinting only. However, due to advancement in materials and technologies, intracoronal splinting can be achieved as well. In this case report, longitudinal fractures in tooth #27, tooth #37, and tooth #46 had occurred. In #27, fracture line was running mesiodistally involving the pulpal floor resulting in a split tooth. In teeth 37 and 46, fractures of the mesiobuccal cusp and mesiolingual cusp were observed, respectively. They were restored with cast gold inlay and full cast crown, respectively. Longitudinal fracture of 27 was treated with an innovative approach using intracanal reinforced composite with Ribbond, external reinforcement with an orthodontic band, and full cast metal crown to splint the split tooth.

  18. Longitudinal emittance measurements at REX-ISOLDE

    CERN Document Server

    Fraser, M A; Jones, R.M.; Jones, R M; Pasini, M; Posocco, P A; Voulot, D; Wenander, F

    2012-01-01

    We report on measurements of the longitudinal emittance at the Radioactive ion beam EXperiment (REX) at ISOLDE, CERN. The rms longitudinal emittance was measured as 0.34 ± 0.08 π ns keV/u at the output of the RFQ and as 0.36 ± 0.04π ns keV/u in front of the third 7-gap split-ring resonator (7G3) using the three-gradient technique; systematic errors are not included but are estimated at approximately 10%. The 86% emittance was measured a factor of approximately 4.4 times larger than the rms emittance at 1.48 ± 0.2 and 1.55 ± 0.12π ns keV/u at the RFQ and 7G3, respectively. The REX switchyard magnet was used as a spectrometer to analyse the energy spread of the beam as it was manipulated by varying the voltage of the rebuncher (ReB) and 7G3 cavities operating at non-accelerating phases. The transfer matrix for a multi-gap bunching cavity is derived and suitably truncated to allow for the accurate reconstruction of the beam parameters from measurement. The technique for measuring the energy spread was rig...

  19. Longitudinal Phase Space Tomography with Space Charge

    CERN Document Server

    Hancock, S; Lindroos, M

    2000-01-01

    Tomography is now a very broad topic with a wealth of algorithms for the reconstruction of both qualitative and quantitative images. In an extension in the domain of particle accelerators, one of the simplest algorithms has been modified to take into account the non-linearity of large-amplitude synchrotron motion. This permits the accurate reconstruction of longitudinal phase space density from one-dimensional bunch profile data. The method is a hybrid one which incorporates particle tracking. Hitherto, a very simple tracking algorithm has been employed because only a brief span of measured profile data is required to build a snapshot of phase space. This is one of the strengths of the method, as tracking for relatively few turns relaxes the precision to which input machine parameters need to be known. The recent addition of longitudinal space charge considerations as an optional refinement of the code is described. Simplicity suggested an approach based on the derivative of bunch shape with the properties of...

  20. Mixture latent autoregressive models for longitudinal data

    CERN Document Server

    Bartolucci, Francesco; Pennoni, Fulvia

    2011-01-01

    Many relevant statistical and econometric models for the analysis of longitudinal data include a latent process to account for the unobserved heterogeneity between subjects in a dynamic fashion. Such a process may be continuous (typically an AR(1)) or discrete (typically a Markov chain). In this paper, we propose a model for longitudinal data which is based on a mixture of AR(1) processes with different means and correlation coefficients, but with equal variances. This model belongs to the class of models based on a continuous latent process, and then it has a natural interpretation in many contexts of application, but it is more flexible than other models in this class, reaching a goodness-of-fit similar to that of a discrete latent process model, with a reduced number of parameters. We show how to perform maximum likelihood estimation of the proposed model by the joint use of an Expectation-Maximisation algorithm and a Newton-Raphson algorithm, implemented by means of recursions developed in the hidden Mark...

  1. Sufficient dimension reduction for longitudinally measured predictors.

    Science.gov (United States)

    Pfeiffer, Ruth M; Forzani, Liliana; Bura, Efstathia

    2012-09-28

    We propose a method to combine several predictors (markers) that are measured repeatedly over time into a composite marker score without assuming a model and only requiring a mild condition on the predictor distribution. Assuming that the first and second moments of the predictors can be decomposed into a time and a marker component via a Kronecker product structure that accommodates the longitudinal nature of the predictors, we develop first-moment sufficient dimension reduction techniques to replace the original markers with linear transformations that contain sufficient information for the regression of the predictors on the outcome. These linear combinations can then be combined into a score that has better predictive performance than a score built under a general model that ignores the longitudinal structure of the data. Our methods can be applied to either continuous or categorical outcome measures. In simulations, we focus on binary outcomes and show that our method outperforms existing alternatives by using the AUC, the area under the receiver-operator characteristics (ROC) curve, as a summary measure of the discriminatory ability of a single continuous diagnostic marker for binary disease outcomes.

  2. Analysis strategies for longitudinal attachment loss data.

    Science.gov (United States)

    Beck, J D; Elter, J R

    2000-02-01

    The purpose of this invited review is to describe and discuss methods currently in use to quantify the progression of attachment loss in epidemiological studies of periodontal disease, and to make recommendations for specific analytic methods based upon the particular design of the study and structure of the data. The review concentrates on the definition of incident attachment loss (ALOSS) and its component parts; measurement issues including thresholds and regression to the mean; methods of accounting for longitudinal change, including changes in means, changes in proportions of affected sites, incidence density, the effect of tooth loss and reversals, and repeated events; statistical models of longitudinal change, including the incorporation of the time element, use of linear, logistic or Poisson regression or survival analysis, and statistical tests; site vs person level of analysis, including statistical adjustment for correlated data; the strengths and limitations of ALOSS data. Examples from the Piedmont 65+ Dental Study are used to illustrate specific concepts. We conclude that incidence density is the preferred methodology to use for periodontal studies with more than one period of follow-up and that the use of studies not employing methods for dealing with complex samples, correlated data, and repeated measures does not take advantage of our current understanding of the site- and person-level variables important in periodontal disease and may generate biased results.

  3. Parental mediation and cyberbullying - a longitudinal study.

    Science.gov (United States)

    Chng, Grace S; Liau, Albert; Khoo, Angeline; Li, Dongdong

    2014-01-01

    Parents use active and restrictive mediation strategies to guide and regulate children's online participation and the online risks they encounter. However, changes in parental mediation do occur over time and the effectiveness of these strategies on cyberbullying demands for further empirical investigation. The current study addresses these issues with a sample of 1084 students (49% girls) in a longitudinal, three-wave design. Gender differences were tested via multi-group analyses. Longitudinal growth models showed that parental use of both active and restrictive mediation decreased over time. For both types of mediation, the mean rate of change had a significant effect on boys' engagement in cyberbullying, but not for girls. Initial levels of restrictive mediation, but not active mediation, were found to be significantly predictive of cyberbullying in both genders. Girls had higher initial levels of both parental mediation types in comparison to boys. The results reveal that the effectiveness of active and restrictive mediation in relation to students' cyberbullying differs and informs us on gender differences. The implications of these results for parental education in online mediation are discussed.

  4. METHODS OF OBTAINING LONGITUDINAL STRIPES LAYOUTS

    Directory of Open Access Journals (Sweden)

    OANA Dorina

    2014-05-01

    Full Text Available From the technological point of view it is necessary that the phase of warping to be done two or three multiple warp, which results in two or three rolls of the warp final will meet only the warping. To achieve longitudinal striped fabric spinning machines is necessary to have all tensioning mechanism dispensing rolls which requires their special construction. The homogeneity of the fabric from the point of view of the warp yarns tension must be ensured by synchronizing operation of the tensioning two cutting mechanisms of the two reels on which the wires are wound with a degree of waving and thus the fuel consumption at the different weaving. It is recommended that the design be adopted average float bonds, such that the wires can be wrapped around more than two final reels. In terms of manufacturing technology with longitudinal stripes fabrics have a more complicated and expensive technology to cross-striped fabrics for the manufacture of which technology is simplified. Cross-striped fabrics containing groups of warp threads those linked to floating average is materially different. Due to this degree of crimping of wires in the stripes with different bonds makes their contract to be different, having a direct influence on the wires consumption. The different contraction of wire weaving makes warp yarn length, contained in a linked reports are so different that it requires winding wires with different bonds also differing on the final rolls.

  5. Longitudinal associations between personality profile stability and adjustment in college students: distinguishing among overall stability, distinctive stability, and within-time normativeness.

    Science.gov (United States)

    Klimstra, Theo A; Luyckx, Koen; Hale, William W; Goossens, Luc; Meeus, Wim H J

    2010-08-01

    In the present study, longitudinal associations of 3 aspects of personality profile stability (i.e., overall stability, distinctive stability, and within-time normativeness) with 3 adjustment measures (i.e., depressive symptoms, self-esteem, and delinquency) were examined, using 4 waves of longitudinal data on a Belgian college sample (N=565). Longitudinal path models revealed strong longitudinal associations between adjustment and overall stability. Subsequent analyses showed that it is not the degree to which one's personality profile consistently diverges from the average personality profile within a population (i.e., distinctive stability) that is related to adjustment but the degree to which a personality profile of an individual matches the average personality profile within the sample at a certain point in time (i.e., within-time normativeness). The current study thereby underscores the importance of distinguishing normativeness and distinctiveness when examining personality profile stability.

  6. Design for a Longitudinal Density Monitor for the LHC

    CERN Document Server

    Bart Pedersen, S; Boccardi, A; Fisher, AS; Jeff, A; Lefevre, T; Rabiller, A; Roncarolo, F; Welsch, CP

    2010-01-01

    Synchrotron radiation is currently used on the LHC for beam imaging and for monitoring the proton population in the 3 microsecond abort gap. In addition to these existing detectors, a study has been initiated to provide longitudinal density profiles of the LHC beams with a high dynamic range and a 50ps time resolution. This would allow for the precise measurement both of the bunch shape and the number of particles in the bunch tail or drifting into ghost bunches. A solution is proposed based on counting synchrotron light photons with two fast avalanche photo-diodes (APD) operated in Geiger mode. One is free-running but heavily attenuated and can be used to measure the core of the bunch. The other is much more sensitive, for measurement of the bunch tails, but must be gated off during the passage of the bunch to prevent the detector from being swamped. An algorithm is then applied to combine the two measurements and correct for the detector dead-time, after pulsing and pileup effects. Initial results from labo...

  7. Spiritual stress and coping model of divorce: a longitudinal study.

    Science.gov (United States)

    Krumrei, Elizabeth J; Mahoney, Annette; Pargament, Kenneth I

    2011-12-01

    This study represents the first longitudinal effort to use a spiritual stress and coping model to predict adults' psychosocial adjustment following divorce. A community sample of 89 participants completed measures at the time of their divorce and 1 year later. Though the sample endorsed slightly lower levels of religiosity than the general U.S. population, most reported spiritual appraisals and positive and negative religious coping tied to divorce. Hierarchical regression analyses controlling general religiousness and nonreligious forms of coping indicated that (a) appraising divorce as a sacred loss or desecration at the time it occurred predicted more depressive symptoms and dysfunctional conflict tactics with the ex-spouse 1 year later; (b) positive religious coping reported about the year following divorce predicted greater posttraumatic growth 1 year after divorce; and (c) negative religious coping reported about the year following divorce predicted more depressive symptoms 1 year after the divorce. Bootstrapping mediation analyses indicated that negative religious coping fully mediated links between appraising the divorce as a sacred loss or desecration at the time it occurred and depressive symptoms 1 year later. In addition, moderation analyses revealed that negative religious coping is more strongly associated with depressive symptoms among those who form high versus low appraisals of their divorce as a sacred loss or desecration. These findings are relevant to divorce education and intervention provided by professionals in legal, family, mental health, and clerical roles. Implications are discussed for clinical and counseling psychology and religious communities.

  8. Population Genetics with Fluctuating Population Sizes

    CERN Document Server

    Chotibut, Thiparat

    2016-01-01

    Standard neutral population genetics theory with a strictly fixed population size has important limitations. An alternative model that allows independently fluctuating population sizes and reproduces the standard neutral evolution is reviewed. We then study a situation such that the competing species are neutral at the equilibrium population size but population size fluctuations nevertheless favor fixation of one species over the other. In this case, a separation of timescales emerges naturally and allows adiabatic elimination of a fast population size variable to deduce the fluctuations-induced selection dynamics near the equilibrium population size. The results highlight the incompleteness of the standard population genetics with a strictly fixed population size.

  9. STATISTICAL GROWTH MODELING OF LONGITUDINAL DT-MRI FOR REGIONAL CHARACTERIZATION OF EARLY BRAIN DEVELOPMENT.

    Science.gov (United States)

    Sadeghi, Neda; Prastawa, Marcel; Fletcher, P Thomas; Gilmore, John H; Lin, Weili; Gerig, Guido

    2012-01-01

    A population growth model that represents the growth trajectories of individual subjects is critical to study and understand neurodevelopment. This paper presents a framework for jointly estimating and modeling individual and population growth trajectories, and determining significant regional differences in growth pattern characteristics applied to longitudinal neuroimaging data. We use non-linear mixed effect modeling where temporal change is modeled by the Gompertz function. The Gompertz function uses intuitive parameters related to delay, rate of change, and expected asymptotic value; all descriptive measures which can answer clinical questions related to growth. Our proposed framework combines nonlinear modeling of individual trajectories, population analysis, and testing for regional differences. We apply this framework to the study of early maturation in white matter regions as measured with diffusion tensor imaging (DTI). Regional differences between anatomical regions of interest that are known to mature differently are analyzed and quantified. Experiments with image data from a large ongoing clinical study show that our framework provides descriptive, quantitative information on growth trajectories that can be directly interpreted by clinicians. To our knowledge, this is the first longitudinal analysis of growth functions to explain the trajectory of early brain maturation as it is represented in DTI.

  10. Longitudinal associations between social anxiety symptoms and cannabis use throughout adolescence: the role of peer involvement.

    Science.gov (United States)

    Nelemans, Stefanie A; Hale, William W; Raaijmakers, Quinten A W; Branje, Susan J T; van Lier, Pol A C; Meeus, Wim H J

    2016-05-01

    There appear to be contradicting theories and empirical findings on the association between adolescent Social Anxiety Disorder (SAD) symptoms and cannabis use, suggesting potential risk as well as protective pathways. The aim of this six-year longitudinal study was to further examine associations between SAD symptoms and cannabis use over time in adolescents from the general population, specifically focusing on the potential role that adolescents' involvement with their peers may have in these associations. Participants were 497 Dutch adolescents (57 % boys; M age = 13.03 at T1), who completed annual self-report questionnaires for 6 successive years. Cross-lagged panel analysis suggested that adolescent SAD symptoms were associated with less peer involvement 1 year later. Less adolescent peer involvement was in turn associated with lower probabilities of cannabis use as well as lower frequency of cannabis use 1 year later. Most importantly, results suggested significant longitudinal indirect paths from adolescent SAD symptoms to cannabis use via adolescents' peer involvement. Overall, these results provide support for a protective function of SAD symptoms in association with cannabis use in adolescents from the general population. This association is partially explained by less peer involvement (suggesting increased social isolation) for those adolescents with higher levels of SAD symptoms. Future research should aim to gain more insight into the exact nature of the relationship between anxiety and cannabis use in adolescents from the general population, especially regarding potential risk and protective processes that may explain this relationship.

  11. Oral health changes in an adult Norwegian population : a cohort analytical approach

    NARCIS (Netherlands)

    Holst, D; Schuller, A A

    2000-01-01

    OBJECTIVES: The purpose of this analysis was to study temporal variation in oral health in an adult population. The cohort analysis comprised 1) estimation of longitudinal, cross-sectional, and time-lag differences in caries and treatment experience of the adult population in Trøndelag from 1973 to

  12. Transverse and longitudinal angular momenta of light

    CERN Document Server

    Bliokh, Konstantin Y

    2015-01-01

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin...

  13. Analysis of aircraft longitudinal handling qualities

    Science.gov (United States)

    Hess, R. A.

    1981-01-01

    The optimal control model (OCM) of the human pilot is applied to the study of aircraft handling qualities. Attention is focused primarily on longitudinal tasks. The modeling technique differs from previous applications of the OCM in that considerable effort is expended in simplifying the pilot/vehicle analysis. After briefly reviewing the OCM, a technique for modeling the pilot controlling higher order systems is introduced. Following this, a simple criterion for determining the susceptibility of an aircraft to pilot induced oscillations (PIO) is formulated. Finally, a model-based metric for pilot rating prediction is discussed. The resulting modeling procedure provides a relatively simple, yet unified approach to the study of a variety of handling qualities problems.

  14. Longitudinal wake field corrections in circular machines

    Energy Technology Data Exchange (ETDEWEB)

    Symon, K.R.

    1996-10-01

    In computations of longitudinal particle motions in accelerators and storage rings, the fields produced by the interactions of the beam with the cavity in which it circulates are usually calculated by multiplying Fourier components of the beam current by the appropriate impedances. This procedure neglects the slow variation with time of the Fourier coefficients and of the beam revolution frequency. When there are cavity elements with decay times that are comparable with or larger than the time during which changes in the beam parameters occur, these changes can not be neglected. Corrections for this effect have been worked out in terms of the response functions of elements in the ring. The result is expressed as a correction to the impedance which depends on the way in which the beam parameters are changing. A method is presented for correcting a numerical simulation by keeping track of the steady state and transient terms in the response of a cavity.

  15. Linear mixed models for longitudinal data

    CERN Document Server

    Molenberghs, Geert

    2000-01-01

    This paperback edition is a reprint of the 2000 edition. This book provides a comprehensive treatment of linear mixed models for continuous longitudinal data. Next to model formulation, this edition puts major emphasis on exploratory data analysis for all aspects of the model, such as the marginal model, subject-specific profiles, and residual covariance structure. Further, model diagnostics and missing data receive extensive treatment. Sensitivity analysis for incomplete data is given a prominent place. Several variations to the conventional linear mixed model are discussed (a heterogeity model, conditional linear mixed models). This book will be of interest to applied statisticians and biomedical researchers in industry, public health organizations, contract research organizations, and academia. The book is explanatory rather than mathematically rigorous. Most analyses were done with the MIXED procedure of the SAS software package, and many of its features are clearly elucidated. However, some other commerc...

  16. Psychosocial adjustment to ALS: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Tamara eMatuz

    2015-09-01

    Full Text Available For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham 1999 has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients’ quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals and coping strategies during a period of two years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years.Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS.

  17. Longitudinal gradients along a reservoir cascade

    Science.gov (United States)

    Miranda, L.E.; Habrat, M.D.; Miyazono, S.

    2008-01-01

    Reservoirs have traditionally been regarded as spatially independent entities rather than as longitudinal segments of a river system that are connected upstream and downstream to the river and other reservoirs. This view has frustrated advancement in reservoir science by impeding adequate organization of available information and by hindering interchanges with allied disciplines that often consider impounded rivers at the basin scale. We analyzed reservoir morphology, water quality, and fish assemblage data collected in 24 reservoirs of the Tennessee River; we wanted to describe longitudinal changes occurring at the scale of the entire reservoir series (i.e., cascade) and to test the hypothesis that fish communities and environmental factors display predictable gradients like those recognized for unimpounded rivers. We used a data set collected over a 7-year period; over 3 million fish representing 94 species were included in the data set. Characteristics such as reservoir mean depth, relative size of the limnetic zone, water retention time, oxygen stratification, thermal stratification, substrate size, and water level fluctuations increased in upstream reservoirs. Conversely, reservoir area, extent of riverine and littoral zones, access to floodplains and associated wetlands, habitat diversity, and nutrient and sediment inputs increased in downstream reservoirs. Upstream reservoirs included few, largely lacustrine, ubiquitous fish taxa that were characteristic of the lentic upper reaches of the basin. Fish species richness increased in a downstream direction from 12 to 67 species/ reservoir as riverine species became more common. Considering impoundments at a basin scale by viewing them as sections in a river or links in a chain may generate insight that is not always available when the impoundments are viewed as isolated entities. Basin-scale variables are rarely controllable but constrain the expression of processes at smaller scales and can facilitate the

  18. Van Kampen modes for bunch longitudinal motion

    Energy Technology Data Exchange (ETDEWEB)

    Burov, A.; /Fermilab

    2010-09-01

    Conditions for existence, uniqueness and stability of bunch steady states are considered. For the existence uniqueness problem, simple algebraic equations are derived, showing the result both for the action and Hamiltonian domain distributions. For the stability problem, van Kampen theory is used. Emerging of discrete van Kampen modes show either loss of Landau damping, or instability. This method can be applied for an arbitrary impedance, RF shape and beam distribution function Available areas on intensity-emittance plane are shown for resistive wall wake and single harmonic, bunch shortening and bunch lengthening RF configurations. Language of van Kampen modes is a powerful tool for studying beam stability. Its unique efficiency reveals itself in those complicated cases, when the dielectric function cannot be obtained, as it is for the longitudinal bunch motion. Emergence of a discrete mode means either loss of Landau damping or instability. By definition, the discrete modes lie outside the continuous incoherent spectrum, but they still may stay within the bucket. In the last case, the discrete mode would disappear after a tiny portion of resonant particles would be added. However, if the discrete mode lie outside the bucket, the Landau damping cannot be restored by tiny perturbation of the particle distribution; LLD is called radical in that case. For a given bunch emittance and RF voltage, the intensity is limited either by reduction of the bucket acceptance or by (radical) LLD. In this paper, results are presented for longitudinal bunch stability in weak head-tail approximation and resistive wall impedance; three RF configurations are studied: single harmonic, bunch shortening and bunch lengthening. It is shown that every RF configuration may be preferable, depending on the bunch emittance and intensity.

  19. Longitudinal changes in lung hyperinflation in COPD

    Science.gov (United States)

    Park, Jimyung; Lee, Chang-Hoon; Lee, Yeon Joo; Park, Jong Sun; Cho, Young-Jae; Lee, Jae Ho; Lee, Choon-Taek; Yoon, Ho Il

    2017-01-01

    Purpose COPD is characterized by an accelerated and progressive decline in forced expiratory volume in 1 second (FEV1) and lung hyperinflation. Although lung hyperinflation is the hallmark of COPD, data on the longitudinal changes in lung hyperinflation and any association with the decline in FEV1 are lacking. The aim of this study was to evaluate the longitudinal changes in lung hyperinflation and to investigate its relationship with FEV1 decline. Patients and methods We conducted a prospective cohort study and studied 176 COPD patients with annual lung volume measurements over a period of 5 years or more. We used a random coefficient model to calculate the annual changes in lung volumes and to evaluate the factors associated with changes in lung hyperinflation. Additionally, the relationship between the change in lung hyperinflation and FEV1 was assessed. Results Residual volume (RV), inspiratory capacity (IC), and total lung capacity (TLC) declined at a mean rate of 39.5, 49.6, and 63.8 mL/year, respectively. While IC/TLC declined at 0.70%/year, RV/TLC also declined at 0.35%/year. Changes in both IC/TLC and RV/TLC varied significantly. Frequent exacerbations led to an increase in RV/TLC and faster decline in IC/TLC over time. RV/TLC declined in 59.7% and increased in 40.3% of the patients. A significant negative correlation was found between the rates of change in FEV1 and RV/TLC, and the rate of decline in FEV1 was greater in patients with an increase in RV/TLC than in those with a decline in RV/TLC (54.2 vs 10.7 mL/year, Prate of change in lung hyperinflation varied greatly among COPD patients. Progression of hyperinflation was associated with frequent exacerbations and a faster decline in FEV1. PMID:28223790

  20. Longitudinal predictors of very early Chinese literacy acquisition

    NARCIS (Netherlands)

    Tong, H.; McBride-Chang, C.; Wong, A.M.-Y.; Hua, S.; Reitsma, P.; Rispens, J.

    2011-01-01

    This 2-year longitudinal study examined both concurrent and longitudinal relations of a variety of reading-related cognitive tasks and Chinese word reading and word dictation among 187 Hong Kong Chinese kindergarteners aged 4-6. Homophone awareness, visual skills and syllable awareness were all uniq

  1. Adolescent Psychosocial Development: A Review of Longitudinal Models and Research

    Science.gov (United States)

    Meeus, Wim

    2016-01-01

    This review used 4 types of longitudinal models (descriptive models, prediction models, developmental sequence models and longitudinal mediation models) to identify regular patterns of psychosocial development in adolescence. Eight patterns of adolescent development were observed across countries: (1) adolescent maturation in multiple…

  2. The estimate and measurement of longitudinal wave intensity

    Science.gov (United States)

    Ruisen, Ming

    1996-08-01

    Quasi-longitudinal waves are one type of structural waves, which are important at high frequencies. This paper studies the estimate theory and measurement technique of quasi-longitudinal waves, analyzes the bias error due to the effect of bending waves. In a two-dimensional quasi-longitudinal wave field, the intensity vector is the sum of the effective intensity vector and the intensity variation vector. Its axial component is proportional to two imaginary parts of cross spectral densities and in the measurement, it is measured by a pair of two-transducer arrays. In a onedimensional quasi-longitudinal wave field, the intensity variation is zero, the intensity is proportional to only one imaginary part of a cross spectral density and it can be measured using a two-transducer array. If bending and quasi-longitudinal waves coexist and the contribution from bending waves cannot be eliminated or reduced to a certain extent, the measured quasi-longitudinal wave intensity will contain a large error. The results measured on the three-beam structure show that quasi-longitudinal wave intensity can be accurately measured using the intensity technique when bending waves are negligible in comparison with quasi-longitudinal waves.

  3. A nonparametric dynamic additive regression model for longitudinal data

    DEFF Research Database (Denmark)

    Martinussen, Torben; Scheike, Thomas H.

    2000-01-01

    dynamic linear models, estimating equations, least squares, longitudinal data, nonparametric methods, partly conditional mean models, time-varying-coefficient models......dynamic linear models, estimating equations, least squares, longitudinal data, nonparametric methods, partly conditional mean models, time-varying-coefficient models...

  4. Learning from Longitudinal Research in Criminology and the Health Sciences

    Science.gov (United States)

    Vanderstaay, Steven L.

    2006-01-01

    This article reviews longitudinal research within criminology and the health sciences on the relationship between reading and criminal, delinquent, or antisocial behavior. Longitudinal research in criminology, medicine, and psychology examines the role of reading within a broad set of interactive processes, connecting literacy to public health via…

  5. Longitudinal Outcomes for Mathematics Achievement for Students with Learning Disabilities

    Science.gov (United States)

    Judge, Sharon; Watson, Silvana M. R.

    2011-01-01

    Using longitudinal data from the first 6 waves of the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K), the authors examined mathematics achievement and growth trajectories by learning disability (LD) subgroups. The 2-level (time-student) growth curve model showed that lower levels of mathematics achievement were already evident at…

  6. A Reference Optical System of Laser Doppler Longitudinal Displacement Measurement

    Institute of Scientific and Technical Information of China (English)

    张存满; 赵洋; 李达成

    2001-01-01

    In this paper, a new reference optical system is put forward to achieve longitudinal displacement measurement. An optical grating is used for frequency mixing and getting high SNR signals in the measurement. Conditions and methods for getting Doppler beat signals are presented.The experiments indicate that this optical syetem can be used to measure the longitudinal displacement with high accuracy.

  7. Longitudinal Trajectories of Perceived Body Weight: Adolescence to Early Adulthood

    Science.gov (United States)

    Seo, Dong-Chul; Li, Kaigang

    2012-01-01

    Objective: To examine longitudinal trajectories of perceived weight from adolescence to early adulthood by gender. Methods: We analyzed 9 waves (1997-2005) of data from the National Longitudinal Survey of Youth (N = 8302) using Mplus. Results: Perceived overweight increased over time among girls and did not level off until 23 years of age. Blacks…

  8. 49 CFR 238.405 - Longitudinal static compressive strength.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Longitudinal static compressive strength. 238.405 Section 238.405 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... II Passenger Equipment § 238.405 Longitudinal static compressive strength. (a) To form an...

  9. Future Orientation, Impulsivity, and Problem Behaviors: A Longitudinal Moderation Model

    Science.gov (United States)

    Chen, Pan; Vazsonyi, Alexander T.

    2011-01-01

    In the current study, based on a sample of 1,873 adolescents between 11.4 and 20.9 years of age from the first 3 waves of the National Longitudinal Study of Adolescent Health, we investigated the longitudinal effects of future orientation on levels of and developmental changes in problem behaviors, while controlling for the effects by impulsivity;…

  10. Change over Time: Conducting Longitudinal Studies of Children's Cognitive Development.

    Science.gov (United States)

    Grammer, Jennie K; Coffman, Jennifer L; Ornstein, Peter A; Morrison, Frederick J

    2013-10-01

    Developmental scientists have argued that the implementation of longitudinal methods is necessary for obtaining an accurate picture of the nature and sources of developmental change (Magnusson & Cairns, 1996; Morrison & Ornstein, 1996; Magnusson & Stattin, 2006). Developmentalists studying cognition have been relatively slow to embrace longitudinal research, and thus few exemplar studies have tracked individual children's cognitive performance over time and even fewer have examined contexts that are associated with this growth. In this article we first outline some of the benefits of implementing longitudinal designs. Using illustrations from existing studies of children's basic cognitive development and of their school-based academic performance, we discuss when it may be appropriate to employ longitudinal (versus other) methods. We then outline methods for integrating longitudinal data into one's research portfolio, contrasting the leveraging of existing longitudinal data sets with the launching of new longitudinal studies in order to address specific questions concerning cognitive development. Finally, for those who are interested in conducting longitudinal investigations of their own, we provide practical on-the-ground guidelines for designing and carrying out such studies of cognitive development.

  11. Early-stage cervical carcinoma, radical hysterectomy, and sexual function. A longitudinal study

    DEFF Research Database (Denmark)

    Jensen, Pernille T; Groenvold, Mogens; Klee, Marianne C

    2004-01-01

    BACKGROUND: Limited knowledge exists concerning the impact of radical hysterectomy (RH) alone on the sexual function of patients with early-stage cervical carcinoma. The authors investigated the longitudinal course of self-reported sexual function after RH. METHODS: The current study was comprised...... with an age-matched control group from the general population. RESULTS: Compared with control women, patients experienced severe orgasmic problems and uncomfortable sexual intercourse due to a reduced vaginal size during the first 6 months after RH, severe dyspareunia during the first 3 months, and sexual...

  12. Longitudinal clinical score prediction in Alzheimer's disease with soft-split sparse regression based random forest.

    Science.gov (United States)

    Huang, Lei; Jin, Yan; Gao, Yaozong; Thung, Kim-Han; Shen, Dinggang

    2016-10-01

    Alzheimer's disease (AD) is an irreversible neurodegenerative disease and affects a large population in the world. Cognitive scores at multiple time points can be reliably used to evaluate the progression of the disease clinically. In recent studies, machine learning techniques have shown promising results on the prediction of AD clinical scores. However, there are multiple limitations in the current models such as linearity assumption and missing data exclusion. Here, we present a nonlinear supervised sparse regression-based random forest (RF) framework to predict a variety of longitudinal AD clinical scores. Furthermore, we propose a soft-split technique to assign probabilistic paths to a test sample in RF for more accurate predictions. In order to benefit from the longitudinal scores in the study, unlike the previous studies that often removed the subjects with missing scores, we first estimate those missing scores with our proposed soft-split sparse regression-based RF and then utilize those estimated longitudinal scores at all the previous time points to predict the scores at the next time point. The experiment results demonstrate that our proposed method is superior to the traditional RF and outperforms other state-of-art regression models. Our method can also be extended to be a general regression framework to predict other disease scores.

  13. Social integration and maternal smoking: A longitudinal analysis of a national birth cohort

    Science.gov (United States)

    Mumford, Elizabeth A; Liu, Weiwei

    2016-01-01

    Objectives Social support and engagement are related to smoking behavior in general populations, but it is unknown whether these measures of social integration as experienced by recent mothers are related to longitudinal maternal smoking patterns. The purpose of this study is, first, to describe longitudinal patterns of maternal smoking before, during, and after pregnancy through the early childhood parenting years, as well as variation in these patterns; and second, to examine these patterns in relation to social integration, emotional, behavioral, and sociodemographic factors. Methods Among 9,050 mothers of the Early Childhood Longitudinal Study-Birth Cohort (a nationally representative probability sample of children born in 2001), we estimated trajectories of maternal smoking with general growth mixture model (GGMM), and examined how baseline predictors are associated with these patterns over a 5 to 6 year period beginning three months prior to pregnancy. Results A 5-class solution identified trajectories of nonsmokers (70.5%), temporary quitters (9.4%), pregnancy-inspired quitters (3.3%), delayed initiators (5.1%), and persistent smokers (11.7%). Modifiable risk factors included postpartum alcohol consumption and behavioral cues from co-resident smokers, while breastfeeding beyond six months and social engagement through religious service attendance were protective characteristics. Conclusions Prevention of and treatment for maternal perinatal and postpartum smoking is best informed by mothers’ emotional, behavioral and sociodemographic characteristics. Religious service attendance, but not measures of social support or social engagement, is a protective factor for maternal smoking trajectories. PMID:26987858

  14. Longitudinal RF capture and acceleration simulation in CSNS RCS

    Institute of Scientific and Technical Information of China (English)

    LIU Lin; TANG Jing-Yu; QIU Jing; WEI Tao

    2009-01-01

    China Spallation Neutron Source(CSNS)is a high power proton accelerator-based facility.Uncontrolled beam loss is a major concern in designing the CSNS to control the radioactivation level.For the Rapid Cycling Synchrotron(RCS)of the CSNS,the repetition frequency is too high for the longitudinal motion to be fully adiabatic.Significant beam loss happens during the RF capture and initial acceleration of the injection period.To reduce the longitudinal beam loss,beam chopping and momentum offset painting methods are used in the RCS injection.This paper presents detailed studies on the longitudinal motion in the RCS by using the ORBIT simulations,which include different beam chopping factors,momentum offsets and RF voltage optimization.With a trade-off between the longitudinal beam loss and transverse incoherent tune shift that will also result in beam losses,optimized longitudinal painting schemes are obtained.

  15. Characterizing Longitudinal Patterns of Physical Activity in Mid-Adulthood Using Latent Class Analysis: Results From a Prospective Cohort Study

    OpenAIRE

    Silverwood, RJ; Nitsch, D.; Pierce, M; Kuh, D; Mishra, GD

    2011-01-01

    : The authors aimed to describe how longitudinal patterns of physical activity during mid-adulthood (ages 31-53 years) can be characterized using latent class analysis in a population-based birth cohort study, the Medical Research Council's 1946 National Survey of Health and Development. Three different types of physical activity-walking, cycling, and leisure-time physical activity-were analyzed separately using self-reported data collected from questionnaires between 1977 and 1999; 3,847 stu...

  16. Longitudinal Investigation of Adaptive Functioning Following Conformal Irradiation for Pediatric Craniopharyngioma and Low-Grade Glioma

    Energy Technology Data Exchange (ETDEWEB)

    Netson, Kelli L. [Department of Psychiatry and Behavioral Sciences, Kansas University School of Medicine—Wichita, Kansas (United States); Conklin, Heather M. [Department of Psychology, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu, Shengjie; Xiong, Xiaoping [Department of Biostatistics, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [Division of Radiation Oncology, St Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2013-04-01

    Purpose: Children treated for brain tumors with conformal radiation therapy experience preserved cognitive outcomes. Early evidence suggests that adaptive functions or independent-living skills may be spared. This longitudinal investigation prospectively examined intellectual and adaptive functioning during the first 5 years following irradiation for childhood craniopharyngioma and low-grade glioma (LGG). The effect of visual impairment on adaptive outcomes was investigated. Methods and Materials: Children with craniopharyngioma (n=62) and LGG (n=77) were treated using conformal or intensity modulated radiation therapy. The median age was 8.05 years (3.21-17.64 years) and 8.09 years (2.20-19.27 years), respectively. Serial cognitive evaluations including measures of intelligence quotient (IQ) and the Vineland Adaptive Behavior Scales (VABS) were conducted at preirradiation baseline, 6 months after treatment, and annually through 5 years. Five hundred eighty-eight evaluations were completed during the follow-up period. Results: Baseline assessment revealed no deficits in IQ and VABS indices for children with craniopharyngioma, with significant (P<.05) longitudinal decline in VABS Communication and Socialization indices. Clinical factors associated with more rapid decline included females and preirradiation chemotherapy (interferon). The only change in VABS Daily Living Skills correlated with IQ change (r=0.34; P=.01) in children with craniopharyngioma. Children with LGG performed below population norms (P<.05) at baseline on VABS Communication, Daily Living Indices, and the Adaptive Behavior Composite, with significant (P<.05) longitudinal decline limited to VABS Communication. Older age at irradiation was a protective factor against longitudinal decline. Severe visual impairment did not independently correlate with poorer adaptive outcomes for either tumor group. Conclusions: There was relative sparing of postirradiation functional outcomes over time in this sample

  17. Longitudinal associations between conduct problems and depressive symptoms among girls and boys with early conduct problems.

    Science.gov (United States)

    Poirier, Martine; Déry, Michèle; Temcheff, Caroline E; Toupin, Jean; Verlaan, Pierrette; Lemelin, Jean-Pascal

    2016-07-01

    Youth with conduct problems (CP) may experience high rates of depressive symptoms (DS). However, little is known about the direction of the longitudinal associations between CP and DS in this specific population. Although girls with CP appear at greater risk than boys for presenting comorbid depression, empirical research on gender differences in these associations is even sparser. The current study used autoregressive latent trajectory models to compare four perspectives with hypotheses regarding the longitudinal associations between CP and DS, while taking into account the evolution of both problems. We also examined gender differences in the longitudinal associations. A total of 345 children (40.6 % female) presenting with a high level of CP in early elementary school (mean age at study inception = 8.52; SD = .94) were evaluated annually over a four-year period (5 measurement time points). The results revealed that CP and DS were quite stable over time. Moreover, CP and DS showed strong covariation at each measurement time point, but only one significant positive cross-lagged association between the two processes, indicating that higher levels of DS at time 3 were associated with higher levels of CP 1 year later. No differences were observed in the longitudinal associations between CP and DS in boys and girls. Given the comorbidity and stability of CP and DS, these findings suggest that DS should be systematically evaluated among children with early clinically significant CP, and treatment plans should include interventions aimed at both CP and DS among children who present with both types of problems.

  18. The methylenetetrahydrofolate reductase C677T genotype and the risk of obesity in three large population-based cohorts

    DEFF Research Database (Denmark)

    Lewis, S.J.; Lawlor, D.A.; Nordestgaard, B.G.

    2008-01-01

    populations from three longitudinal studies based in the UK and Denmark in which DNA for genotyping was obtained along with measures of obesity. Methods: Our subjects were taken from the British Women's Heart and Health Study (BWHHS), the Avon Longitudinal Study of Parents and Children (two populations......: mothers and children) and the Copenhagen City Heart Study. We performed analyses separately by population, and then carried out a meta-analysis, combining similar populations. Results: Initial findings in the BWHHS suggested that the TT genotype may be associated with an increased risk of obesity BMI 3 0...

  19. Longitudinal Surveys of Australian Youth (LSAY): 1995 Cohort--User Guide. Data Elements B1: Education. Technical Report 49B1

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2009

    2009-01-01

    This technical paper contains information about the variables in the LSAY (Longitudinal Surveys of Australian Youth) Y95 cohort data set. It groups each variable into data elements which identifies common variables within and across waves. Information is provided about each data element including its purpose, values, base populations and relevant.…

  20. Longitudinal Surveys of Australian Youth (LSAY): 1995 Cohort--User Guide. Data Elements B2: Education. Technical Report 49B2

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2009

    2009-01-01

    This technical paper contains information about the variables in the Longitudinal Surveys of Australian Youth (LSAY) Year 95 cohort data set. It groups each variable into data elements that identify common variables within and across waves. Information is provided about each data element, including its purpose, values, base populations and…

  1. Health-related quality of life is associated with physical activity levels among colorectal cancer survivors: a longitudinal, 3-year study of the PROFILES registry

    NARCIS (Netherlands)

    Husson, O.; Mols, F.; Ezendam, N.P.; Schep, G.; Poll-Franse, L.V. van de

    2015-01-01

    PURPOSE: The present study aims to examine the longitudinal relation between physical activity (PA) and health-related quality of life (HRQoL) among colorectal cancer (CRC) survivors. METHODS: Individuals diagnosed with CRC between 2000 and 2009 as registered by the Dutch population-based Eindhoven

  2. Tracking HCV protease population diversity during transmission and susceptibility of founder populations to antiviral therapy

    Science.gov (United States)

    Khera, Tanvi; Todt, Daniel; Vercauteren, Koen; McClure, C. Patrick; Verhoye, Lieven; Farhoudi, Ali; Bhuju, Sabin; Geffers, Robert; Baumert, Thomas F.; Steinmann, Eike; Meuleman, Philip; Pietschmann, Thomas; Brown, Richard J.P.

    2017-01-01

    Due to the highly restricted species-tropism of Hepatitis C virus (HCV) a limited number of animal models exist for pre-clinical evaluation of vaccines and antiviral compounds. The human-liver chimeric mouse model allows heterologous challenge with clinically relevant strains derived from patients. However, to date, the transmission and longitudinal evolution of founder viral populations in this model have not been characterized in-depth using state-of-the-art sequencing technologies. Focusing on NS3 protease encoding region of the viral genome, mutant spectra in a donor inoculum and individual recipient mice were determined via Illumina sequencing and compared, to determine the effects of transmission on founder viral population complexity. In all transmissions, a genetic bottleneck was observed, although diverse viral populations were transmitted in each case. A low frequency cloud of mutations ( 1% restricted to a subset of nucleotides. The population of SNVs >1% was reduced upon transmission while the low frequency SNV cloud remained stable. Fixation of multiple identical synonymous substitutions was apparent in independent transmissions, and no evidence for reversion of T-cell epitopes was observed. In addition, susceptibility of founder populations to antiviral therapy was assessed. Animals were treated with protease inhibitor (PI) monotherapy to track resistance associated substitution (RAS) emergence. Longitudinal analyses revealed a decline in population diversity under therapy, with no detectable RAS >1% prior to therapy commencement. Despite inoculation from a common source and identical therapeutic regimens, unique RAS emergence profiles were identified in different hosts prior to and during therapeutic failure, with complex mutational signatures at protease residues 155, 156 and 168 detected. Together these analyses track viral population complexity at high-resolution in the human-liver chimeric mouse model post-transmission and under therapeutic

  3. Tracking HCV protease population diversity during transmission and susceptibility of founder populations to antiviral therapy.

    Science.gov (United States)

    Khera, Tanvi; Todt, Daniel; Vercauteren, Koen; McClure, C Patrick; Verhoye, Lieven; Farhoudi, Ali; Bhuju, Sabin; Geffers, Robert; Baumert, Thomas F; Steinmann, Eike; Meuleman, Philip; Pietschmann, Thomas; Brown, Richard J P

    2017-03-01

    Due to the highly restricted species-tropism of Hepatitis C virus (HCV) a limited number of animal models exist for pre-clinical evaluation of vaccines and antiviral compounds. The human-liver chimeric mouse model allows heterologous challenge with clinically relevant strains derived from patients. However, to date, the transmission and longitudinal evolution of founder viral populations in this model have not been characterized in-depth using state-of-the-art sequencing technologies. Focusing on NS3 protease encoding region of the viral genome, mutant spectra in a donor inoculum and individual recipient mice were determined via Illumina sequencing and compared, to determine the effects of transmission on founder viral population complexity. In all transmissions, a genetic bottleneck was observed, although diverse viral populations were transmitted in each case. A low frequency cloud of mutations ( 1% restricted to a subset of nucleotides. The population of SNVs >1% was reduced upon transmission while the low frequency SNV cloud remained stable. Fixation of multiple identical synonymous substitutions was apparent in independent transmissions, and no evidence for reversion of T-cell epitopes was observed. In addition, susceptibility of founder populations to antiviral therapy was assessed. Animals were treated with protease inhibitor (PI) monotherapy to track resistance associated substitution (RAS) emergence. Longitudinal analyses revealed a decline in population diversity under therapy, with no detectable RAS >1% prior to therapy commencement. Despite inoculation from a common source and identical therapeutic regimens, unique RAS emergence profiles were identified in different hosts prior to and during therapeutic failure, with complex mutational signatures at protease residues 155, 156 and 168 detected. Together these analyses track viral population complexity at high-resolution in the human-liver chimeric mouse model post-transmission and under therapeutic

  4. Nationwide and population-based prescription patterns in bipolar disorder

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

    2016-01-01

    OBJECTIVES: The aim of the present study was to describe prescription patterns and changes in these patterns over the last decade for patients diagnosed with bipolar disorder in mental healthcare, using population-based and nationwide data, and to relate the findings to recommendations from...... international guidelines. METHODS: A population-based, nationwide study was carried out. It included register-based longitudinal data on all patients with a first-ever contact with mental healthcare with a diagnosis of mania/bipolar disorder from the entire Danish population, and all prescription data...

  5. Longitudinal phase space tomography with space charge

    Science.gov (United States)

    Hancock, S.; Lindroos, M.; Koscielniak, S.

    2000-12-01

    Tomography is now a very broad topic with a wealth of algorithms for the reconstruction of both qualitative and quantitative images. In an extension in the domain of particle accelerators, one of the simplest algorithms has been modified to take into account the nonlinearity of large-amplitude synchrotron motion. This permits the accurate reconstruction of longitudinal phase space density from one-dimensional bunch profile data. The method is a hybrid one which incorporates particle tracking. Hitherto, a very simple tracking algorithm has been employed because only a brief span of measured profile data is required to build a snapshot of phase space. This is one of the strengths of the method, as tracking for relatively few turns relaxes the precision to which input machine parameters need to be known. The recent addition of longitudinal space charge considerations as an optional refinement of the code is described. Simplicity suggested an approach based on the derivative of bunch shape with the properties of the vacuum chamber parametrized by a single value of distributed reactive impedance and by a geometrical coupling coefficient. This is sufficient to model the dominant collective effects in machines of low to moderate energy. In contrast to simulation codes, binning is not an issue since the profiles to be differentiated are measured ones. The program is written in Fortran 90 with high-performance Fortran extensions for parallel processing. A major effort has been made to identify and remove execution bottlenecks, for example, by reducing floating-point calculations and recoding slow intrinsic functions. A pointerlike mechanism which avoids the problems associated with pointers and parallel processing has been implemented. This is required to handle the large, sparse matrices that the algorithm employs. Results obtained with and without the inclusion of space charge are presented and compared for proton beams in the CERN protron synchrotron booster. Comparisons

  6. Longitudinal static stability requirements for wing in ground effect vehicle

    Science.gov (United States)

    Yang, Wei; Yang, Zhigang; Collu, Maurizio

    2015-06-01

    The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  7. Longitudinal static stability requirements for wing in ground effect vehicle

    Directory of Open Access Journals (Sweden)

    Yang Wei

    2015-06-01

    Full Text Available The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

  8. Tunable Single-Longitudinal-Mode High-Power Fiber Laser

    Directory of Open Access Journals (Sweden)

    Jonas K. Valiunas

    2012-01-01

    Full Text Available We report a novel CW tunable high-power single-longitudinal-mode fiber laser with a linewidth of ∼9 MHz. A tunable fiber Bragg grating provided wavelength selection over a 10 nm range. An all-fiber Fabry-Perot filter was used to increase the longitudinal mode spacing of the laser cavity. An unpumped polarization-maintaining erbium-doped fiber was used inside the cavity to eliminate mode hopping and increase stability. A maximum output power of 300 mW was produced while maintaining single-longitudinal-mode operation.

  9. Longitudinal dynamic stability of a shuttle vehicle.

    Science.gov (United States)

    Vinh, N. X.; Laitone, E. V.

    1972-01-01

    Analytical study of the longitudinal dynamic stability of a nonrolling, lifting vehicle gliding at hypersonic speeds. The analysis applies to shuttle vehicles designed for operating up to the rim of a planetary atmosphere. A general nondimensional time transformation is introduced to derive a unified second-order linear differential equation for the angle of attack, valid for all types of reentry of a general type of vehicle. The stability of motion is discussed for two fundamental regimes of flight that are based on widely different assumptions. For near ballistic entry along a straight line trajectory, the equation reduces to a confluent hypergeometric equation, the solution of which can be expressed in terms of Whittaker's function. Using a theorem in the theory of stability of differential equations, criteria for damped oscillations are derived. It is shown that the aerodynamic criteria for stability are the same as for the case of ballistic entry. In addition, for each vehicle configuration, and specified planetary atmosphere, there exists an altitude range where the angle of attack frequency is nearly equal to the orbital frequency causing instability in pitch. This resonance instability is due to the ellipticity of the orbit. Criteria for eccentricity instability are derived.

  10. The Fundamentals of Longitudinal Research: An Overview

    Directory of Open Access Journals (Sweden)

    Rajulton, Fernando

    2001-01-01

    Full Text Available EnglishThis paper outlines briefly the historical development of ideas related tolongitudinal studies and their advantages over cross-sectional studies. Then it points out a fewcomplicating factors that arise with the analysis of longitudinal data and highlights some of theapproaches adopted to manage those complicating factors and illustrated in the papers included in thisSpecial Issue. The overall aim is to promote a better understanding of the information thatlongitudinal data provide and of the suitable techniques needed to analyze such data.FrenchCet article trace brièvement le développement historique des idées liées àl’avantage des études longitudinales par rapport aux études transversales. Je préciseensuite quelques facteurs qui compliquent les analyses des données longitudinaleset je met en valeur certaines des approches adoptées pour contrôler ces facteurs etj’illustre par des exemples tirés de cette édition spéciale. Le but général estd’atteindre une meilleure compréhension de l'information que les donnéeslongitudinales fournissent et des techniques appropriées requises pour analyser detelles données.

  11. Laser Wakefield diagnostic using holographic longitudinal interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Volfbeyn, P.; Esarey, E.; Leemans, W.P.

    1999-03-26

    We propose a diagnostic technique for wakefield measurement in plasma channels. A new technique for plasma channel creation, the Ignitor Heater scheme was proposed and experimentally tested in hydrogen and nitrogen previously. It makes use of two laser pulses. The Ignitor, an ultrashort (sub 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used to heat the existing spark via in-verse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. Laser pulses injected into such plasma channels produce a plasma wake that has a phase velocity close to the speed of light. A discussion of plasma wake measurements, using a Longitudinal Interferometry Wakefield Diagnostic Based on Time Domain Rayleigh Refractometry with Holographic Inversion, will be presented.

  12. Longitudinal wake field corrections in circular machines

    Energy Technology Data Exchange (ETDEWEB)

    Symon, K.R. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)]|[Dept. of Physics, University of Wisconsin-Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States)

    1997-02-01

    In computations of longitudinal particle motions in accelerators and storage rings, the fields produced by the interactions of the beam with the cavity in which it circulates are usually calculated by multiplying Fourier components of the beam current by the appropriate impedances. This procedure neglects the slow variation with time of the Fourier coefficients and of the beam revolution frequency. When there are cavity elements with decay times that are comparable with or larger than the time during which changes in the beam parameters occur, these changes can not be neglected. Corrections for this effect have been worked out in terms of the response functions of elements in the ring. The result is expressed as a correction to the impedance which depends on the way in which the beam parameters are changing. A method is presented for correcting a numerical simulation by keeping track of the steady state and transient terms in the response of a cavity. {copyright} {ital 1997 American Institute of Physics.}

  13. Analysis of critically refracted longitudinal waves

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Ning, E-mail: npei@iastate.edu; Bond, Leonard J., E-mail: npei@iastate.edu [Center for Nondestructive Evaluation, Iowa State University, Ames, IA 50011 (United States)

    2015-03-31

    Fabrication processes, such as, welding, forging, and rolling can induce residual stresses in metals that will impact product performance and phenomena such as cracking and corrosion. To better manage residual stress tools are needed to map their distribution. The critically refracted ultrasonic longitudinal (LCR) wave is one such approach that has been used for residual stress characterization. It has been shown to be sensitive to stress and less sensitive to the effects of the texture of the material. Although the LCR wave is increasingly widely applied, the factors that influence the formation of the LCR beam are seldom discussed. This paper reports a numerical model used to investigate the transducers' parameters that can contribute to the directionality of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal test method is used to study the transducer parameters which influence the LCR wave beams. This method provides a design tool that can be used to study and optimize multiple parameter experiments and it can identify which parameter or parameters are of most significance. The simulation of the sound field in a 2-D 'water-steel' model is obtained using a Spatial Fourier Analysis method. The effects of incident angle, standoff, the aperture and the center frequency of the transducer were studied. Results show that the aperture of the transducer, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields.

  14. Analysis of critically refracted longitudinal waves

    Science.gov (United States)

    Pei, Ning; Bond, Leonard J.

    2015-03-01

    Fabrication processes, such as, welding, forging, and rolling can induce residual stresses in metals that will impact product performance and phenomena such as cracking and corrosion. To better manage residual stress tools are needed to map their distribution. The critically refracted ultrasonic longitudinal (LCR) wave is one such approach that has been used for residual stress characterization. It has been shown to be sensitive to stress and less sensitive to the effects of the texture of the material. Although the LCR wave is increasingly widely applied, the factors that influence the formation of the LCR beam are seldom discussed. This paper reports a numerical model used to investigate the transducers' parameters that can contribute to the directionality of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal test method is used to study the transducer parameters which influence the LCR wave beams. This method provides a design tool that can be used to study and optimize multiple parameter experiments and it can identify which parameter or parameters are of most significance. The simulation of the sound field in a 2-D "water-steel" model is obtained using a Spatial Fourier Analysis method. The effects of incident angle, standoff, the aperture and the center frequency of the transducer were studied. Results show that the aperture of the transducer, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields.

  15. Longitudinal dynamics of a perching aircraft concept

    Science.gov (United States)

    Wickenheiser, Adam; Garcia, Ephrahim; Waszak, Martin

    2005-05-01

    This paper introduces a morphing aircraft concept whose purpose is to demonstrate a new bio-inspired flight capability: perching. Perching is a maneuver that utilizes primarily aerodynamics -- as opposed to thrust generation -- to achieve a vertical or short landing. The flight vehicle that will accomplish this is described herein with particular emphasis on its addition levels of actuation beyond the traditional aircraft control surfaces. A computer model of the aircraft is developed in order to predict the changes in applied aerodynamic loads as it morphs and transitions through different flight regimes. The analysis of this model is outlined, including a lifting-line-based analytical technique and a trim and stability analysis. These analytical methods -- compared to panel or computational fluid dynamics (CFD) methods -- are considered desirable for the analysis of a large number of vehicle configurations and flight conditions. The longitudinal dynamics of this aircraft are studied, and several interesting results are presented. Of special interest are the changes in vehicle dynamics as the aircraft morphs from a cruise configuration to initiate the perching maneuver. Changes in trim conditions and stability are examined as functions of vehicle geometry. The time response to changes in vehicle configuration is also presented.

  16. A 16-year longitudinal study of hearing in very old Australians

    Directory of Open Access Journals (Sweden)

    L. Sanchez

    2011-03-01

    Full Text Available Hearing impairment is recognised for its prominence among the chronic conditions of ageing, being more prevalent in Australia than all other national health priorities except musculo-skeletal conditions (Australian Institute of Health and Welfare, 2004. However despite its prevalence, there have been fewer epidemiological studies of hearing impairment than for other chronic diseases and disorders. Epidemiological data based on audiological evaluations are scant and a rigorously defined burden of illness for hearing impairment at a population or community level using both audiological and self-report types of estimate is still only available from a few studies world-wide (Gates et al., 1990; Davis, 1995; Wilson et al., 1998; Cruikshanks et al., 1998. Longitudinal studies are particularly valuable in providing information about patterns of ageing, about cohort differences in age-related physical, sensory and psychological functioning and for the services which an ageing population might require...

  17. Effective population size of korean populations.

    Science.gov (United States)

    Park, Leeyoung

    2014-12-01

    Recently, new methods have been developed for estimating the current and recent changes in effective population sizes. Based on the methods, the effective population sizes of Korean populations were estimated using data from the Korean Association Resource (KARE) project. The overall changes in the population sizes of the total populations were similar to CHB (Han Chinese in Beijing, China) and JPT (Japanese in Tokyo, Japan) of the HapMap project. There were no differences in past changes in population sizes with a comparison between an urban area and a rural area. Age-dependent current and recent effective population sizes represent the modern history of Korean populations, including the effects of World War II, the Korean War, and urbanization. The oldest age group showed that the population growth of Koreans had already been substantial at least since the end of the 19th century.

  18. Estimating the prevalence of chronic pain: validation of recall against longitudinal reporting (the HUNT pain study).

    Science.gov (United States)

    Landmark, Tormod; Romundstad, Pål; Dale, Ola; Borchgrevink, Petter C; Kaasa, Stein

    2012-07-01

    Methods for classifying chronic pain in population studies are highly variable, and prevalence estimates ranges from 11% to 64%. Limited knowledge about the persistence of pain and the validity of recall questions defining chronic pain make findings difficult to interpret and compare. The primary aim of the current study was to characterize the persistence of pain in the general population and to validate recall measures against longitudinal reporting of pain. A random sample of 6419 participants from a population study (the HUNT 3 study in Norway) was invited to report pain on the SF-8 verbal pain rating scale every 3 months over a 12-month period and to report pain lasting more than 6 months at 12-month follow-up. Complete data were obtained from 3364 participants. Pain reporting was highly stable (intraclass correlation 0.66, 95% confidence interval 0.65 to 0.67), and the prevalence of chronic pain varied considerably according to level of severity and persistence: 31% reported mild pain or more, whereas 2% reported severe pain on 4 of 4 consecutive measurements. When defined as moderate pain or more on at least 3 of 4 consecutive measurements, the prevalence was 26%. Compared with the longitudinal classification, a cross-sectional measure of moderate pain or more during the last week on the SF-8 scale presented a sensitivity of 82% and a specificity of 84%, and a sensitivity of 80% and a specificity of 90% when combined with a 6-month recall question. Thus pain reporting in the general population is stable and cross-sectional measures may give valid prevalence estimates of chronic pain.

  19. Predicting Early School Achievement with the EDI: A Longitudinal Population-Based Study

    Science.gov (United States)

    Forget-Dubois, Nadine; Lemelin, Jean-Pascal; Boivin, Michel; Dionne, Ginette; Seguin, Jean R.; Vitaro, Frank; Tremblay, Richard E.

    2007-01-01

    School readiness tests are significant predictors of early school achievement. Measuring school readiness on a large scale would be necessary for the implementation of intervention programs at the community level. However, assessment of school readiness is costly and time consuming. This study assesses the predictive value of a school readiness…

  20. Sleep disorders and demand for medical services: evidence from a population-based longitudinal study.

    Directory of Open Access Journals (Sweden)

    Rogerio Santos-Silva

    Full Text Available BACKGROUND: The aim of this study was to investigate whether insomnia and obstructive sleep apnea (OSA were predictors of hospitalizations or emergency department visits during two years following the Sao Paulo Epidemiologic Sleep Study (EPISONO sample. METHODS AND FINDINGS: All participants (n = 1,101 who underwent a baseline evaluation between July and December 2007 were contacted in December 2009 and asked to fill out a questionnaire about body weight changes, number of hospitalizations and visits to the emergency department. Participants lost during the follow-up period represented 3.2% (n = 35 and 7 subjects had died. Hospitalizations were reported by 116 volunteers (10.5% and emergency department visits were reported by 136 participants (12.4%. The average body mass index (BMI did not vary significantly between the first and the second assessment [26.7(95%CI:26.3-27.1 vs. 26.9(26.5-27.4 kg/m2]. After adjusting for confounders, a multiple logistic regression model revealed that female gender [1.4(1.0-1.9], age ≥ 40 years, insomnia diagnosed according to the DSM-IV criteria [1.6(1.0-2.6], and apnea-hypopnea index ≥ 15 [1.5(1.0-2.2] were predictors of hospitalizations and/or demand for emergency services. CONCLUSION: Our study of a probabilistic sample of the Sao Paulo inhabitants shows that over a period of two years, insomnia and OSA were both associated with health impairment. Considering the high prevalence and public health burden of sleep disorders, the consequences of untreated disease for both the individual and society are undeniable and should be addressed.

  1. Parity and 11-Year Serum Thyrotropin and Thyroid Autoantibody Change: A Longitudinal Population-Based Study

    DEFF Research Database (Denmark)

    Bjergved, Lena; Carlé, Allan; Jørgensen, Torben

    2016-01-01

    A role for female reproductive factors in the pathogenesis of thyroid autoimmunity has been suggested. This study investigated the prospective association between parity, abortion, use of oral contraceptive pill (OCP), and use of hormone replacement therapy (HRT), and 11-year change in serum...

  2. Testosterone during Pregnancy and Gender Role Behavior of Preschool Children: A Longitudinal, Population Study.

    Science.gov (United States)

    Hines, Melissa; Golombok, Susan; Rust, John; Johnston, Katie J.; Golding, Jean

    2002-01-01

    Related blood levels of testosterone and sex hormone-binding globulin in pregnant women to gender role behavior among 342 male and 337 female offspring at 3.5 years. Found that testosterone levels related linearly to girls' gender role behavior. Neither hormone related to boys' gender role behavior. Other factors, including older brothers or…

  3. Increased prevalence of eosinophilia in a hemodialysis population: Longitudinal and case control studies.

    Science.gov (United States)

    Hildebrand, Sarah; Corbett, Richard; Duncan, Neill; Ashby, Damien

    2016-07-01

    Eosinophilia is commonly found in patients with clinical reactions to the hemodialysis circuit. With modern membranes, such reactions have become less common, but they may be under diagnosed in patients with subtle symptoms, in whom the presence of eosinophilia is an important diagnostic feature. Two case reports are presented, along with a hemodialysis study of the frequency and clinical associations of eosinophilia. In three hemodialysis facilities, all current hemodialysis patients with persistent eosinophilia (greater than 1 × 10(9) /L for 3 months) were identified. Control patients without eosinophilia (less than 0.5 × 10(9) /L for 3 months) matched for age, gender, and ethnicity were identified from the same facilities. A historical cohort of patients, dialyzing at the same facilities 5 years ago, was screened for the presence of persistent eosinophilia. From 510 patients, 24 cases of persistent eosinophilia were identified (4.7%). The median eosinophil count was 1.75 × 10(9) /L (range 1.1-7.5 × 10(9) /L). The prevalence in a historical cohort 5 years previously was significantly less at 1.5% (P = 0.046). Compared to controls, patients with eosinophilia were more likely to be on an angiotensin converting enzyme inhibitor (41.7% vs. 12.5%, P = 0.049), had a lower C-reactive protein (10 vs. 24 mg/L, P = 0.02) and were more likely to be using a fistula for access (P = 0.049). Over the following 12 months, there was no difference in the mean number of hospital admission days between cases and controls (7.6 vs. 11.5 days, P = 0.54), and no difference in mortality over 29 months (25.0% vs. 29.2%, P = 1.00). Eosinophilia remains not uncommon in hemodialysis patients, and in most cases reflects allergy to components of the dialysis circuit, which is usually subclinical. The overall prognosis for asymptomatic patients appears to be favourable.

  4. Gastrointestinal symptoms related to the irritable bowel syndrome - a longitudinal population-based register study

    DEFF Research Database (Denmark)

    Poulsen, Chalotte Heinsvig; Eplov, Lene Falgaard; Hjorthoj, Carsten;

    2016-01-01

    symptom groups and mortality (p = 0.47). IBS and GI symptoms with abdominal pain were significantly associated with development of GI diseases. Only GI symptoms with abdominal pain were associated with development of severe GI diseases (HR: 1.38; 95% CI: [1.06-1.79]). There were no statistically......, but continue to report frequent abdominal pain. Coexisting symptoms did not influence mortality and development of GI diseases....

  5. Sexual orientation and suicide attempt: a longitudinal study of the general Norwegian adolescent population.

    Science.gov (United States)

    Wichstrøm, Lars; Hegna, Kristinn

    2003-02-01

    Past and future suicide attempt rates among gay, lesbian, and bisexual (GLB) young people were compared with those of heterosexual young people. A sample of Norwegian students (N = 2.924; grades 7-12) was followed in 3 data collection waves. Risk factors included previous suicide attempt,depressed mood, eating problems, conduct problems, early sexual debut, number of sexual partners, pubertal timing, self-concept, alcohol and drug use, atypical gender roles, loneliness, peer relations, social support, parental attachment, parental monitoring, and suicidal behavior among family and friends. When homosexual attraction, homosexual identity, and same-sex sexual behavior were entered to predict suicide attempt, only same-sex sexual behavior was significantly predictive. The increased odds could not be attributed to GLB students' greater exposure to risk factors for suicide attempt.

  6. The Association between Intelligence and Telomere Length : A Longitudinal Population Based Study

    NARCIS (Netherlands)

    Kingma, Eva M.; de Jonge, Peter; van der Harst, Pim; Ormel, Johan; Rosmalen, Judith G. M.

    2012-01-01

    Low intelligence has been associated with poor health and mortality, but underlying mechanisms remain obscure. We hypothesized that low intelligence is associated with accelerated biological ageing as reflected by telomere length; we suggested potential mediation of this association by unhealthy beh

  7. The Ethics of Organizations: A Longitudinal Study of the U.S. Working Population

    NARCIS (Netherlands)

    S.P. Kaptein (Muel)

    2009-01-01

    textabstractThe ethics of organizations has received much attention in recent years. This raises the question whether the ethics of organizations has also improved. In 1999, 2004 and 2008, a survey was conducted of 12,196 U.S. managers and employees. The results show that the ethical culture of orga

  8. Midlife psychological stress and risk of dementia: a 35-year longitudinal population study.

    Science.gov (United States)

    Johansson, Lena; Guo, Xinxin; Waern, Margda; Ostling, Svante; Gustafson, Deborah; Bengtsson, Calle; Skoog, Ingmar

    2010-08-01

    The number of people with dementia has increased dramatically with global ageing. Nevertheless, the pathogeneses of these diseases are not sufficiently understood. The present study aims to analyse the relationship between psychological stress in midlife and the development of dementia in late-life. A representative sample of females (n = 1462) aged 38-60 years were examined in 1968-69 and re-examined in 1974-75, 1980-81, 1992-93 and 2000-03. Psychological stress was rated according to a standardized question in 1968, 1974 and 1980. Dementia was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders criteria based on information from neuropsychiatric examinations, informant interviews, hospital records and registry data. During the 35-year follow-up, 161 females developed dementia (105 Alzheimer's disease, 40 vascular dementia and 16 other dementias). We found that the risk of dementia (hazard ratios, 95% confidence intervals) was increased in females reporting frequent/constant stress in 1968 (1.60, 1.10-2.34), in 1974 (1.65, 1.12-2.41) and in 1980 (1.60, 1.01-2.52). Frequent/constant stress reported in 1968 and 1974 was associated with Alzheimer's disease. Reporting stress at one, two or three examinations was related to a sequentially higher dementia risk. Compared to females reporting no stress, hazard ratios (95% confidence intervals) for incident dementia were 1.10 (0.71-1.71) for females reporting frequent/constant stress at one examination, 1.73 (1.01-2.95) for those reporting stress at two examinations and 2.51 (1.33-4.77) at three examinations. To conclude, we found an association between psychological stress in middle-aged women and development of dementia, especially Alzheimer's disease. More studies are needed to confirm our findings and to study potential neurobiological mechanisms of these associations.

  9. Development of Anxiety Disorders in a Traumatized Pediatric Population: A Preliminary Longitudinal Evaluation

    Science.gov (United States)

    Cortes, Adriana M.; Saltzman, Kassey M.; Weems, Carl F.; Regnault, Heather P.; Reiss, Allan L.; Carrion, Victor G.

    2005-01-01

    Objective: The current study was conducted to determine if post-traumatic stress disorder (PTSD) symptomatology predicted later development of non-PTSD anxiety disorders in children and adolescents victimized by interpersonal trauma. Methods: Thirty-four children with a history of interpersonal trauma and no initial diagnosis of anxiety disorder…

  10. Prenatal exposure to bereavement and type-2 diabetes: a Danish longitudinal population based study.

    Directory of Open Access Journals (Sweden)

    Jasveer Virk

    Full Text Available BACKGROUND: The etiology of type-2 diabetes is only partly known, and a possible role of prenatal stress in programming offspring for insulin resistance has been suggested by animal models. Previously, we found an association between prenatal stress and type-1 diabetes. Here we examine the association between prenatal exposure to maternal bereavement during preconception and pregnancy and development of type-2 diabetes in the off-spring. METHODS: We utilized data from the Danish Civil Registration System to identify singleton births in Denmark born January 1(st 1979 through December 31(st 2008 (N = 1,878,246, and linked them to their parents, grandparents, and siblings. We categorized children as exposed to bereavement during prenatal life if their mothers lost an elder child, husband or parent during the period from one year before conception to the child's birth. We identified 45,302 children exposed to maternal bereavement; the remaining children were included in the unexposed cohort. The outcome of interest was diagnosis of type-2 diabetes. We estimated incidence rate ratios (IRRs from birth using log-linear poisson regression models and used person-years as the offset variable. All models were adjusted for maternal residence, income, education, marital status, sibling order, calendar year, sex, and parents' history of diabetes at the time of pregnancy. RESULTS: We found children exposed to bereavement during their prenatal life were more likely to have a type-2 diabetes diagnosis later in life (aIRR: 1.31, 1.01-1.69. These findings were most pronounced when bereavement was caused by death of an elder child (aIRR: 1.51, 0.94-2.44. Results also indicated the second trimester of pregnancy to be the most sensitive period of bereavement exposure (aIRR:2.08, 1.15-3.76. CONCLUSIONS: Our data suggests that fetal exposure to maternal bereavement during preconception and the prenatal period may increase the risk for developing type-2 diabetes in childhood and young adulthood.

  11. The influence of maternal vulnerability and parenting stress on chronic pain in adolescents in a general population sample : The TRAILS study

    NARCIS (Netherlands)

    Darlington, A-S. E.; Verhulst, F. C.; De Winter, A. F.; Ormel, J.; Passchier, J.; Hunfeld, J. A. M.

    2012-01-01

    Investigating possible psychosocial predictors of unexplained chronic pain in adolescents is crucial in understanding its development and prevention. A general population sample of adolescents (n = 2230) from the TRAILS cohort study was investigated longitudinally to assess the influence of maternal

  12. Motor performance after neonatal extracorporeal membrane oxygenation: a longitudinal evaluation

    NARCIS (Netherlands)

    Cammen-Zijp, M.H. van der; Janssen, A.J.W.M.; Raets, M.M.; Rosmalen, J. van; Govaert, P.; Steiner, K.; Gischler, S.J.; Tibboel, D.; Heijst, A.F.J. van; Ijsselstijn, H.

    2014-01-01

    OBJECTIVE: To assess longitudinally children's motor performance 5 to 12 years after neonatal extracorporeal membrane oxygenation (ECMO) and to evaluate associations between clinical characteristics and motor performance. METHODS: Two hundred fifty-four neonatal ECMO survivors in the Netherlands wer

  13. A New Kicker for the TLS Longitudinal Feedback System

    CERN Document Server

    Lau, Wai-Keung; Dehler, Micha; Hsu, Kuo-Tung; Hsu, San-Yuang; Jung Chou Ping; Wei Chen, Cheng; Yang Chen Huan; Yang Tze Te

    2005-01-01

    A new longitudinal kicker that is modified from the Swiss Light Source (SLS) design to fit into the TLS storage ring. It will be served as the actuator in the longitudinal multi-bunch feedback control loop. Beam coupling impedance has been calculated by Gdfidl with a PC cluster. Previous to the installation of this new kicker, bench measurement has been performed in the laboratory to characterize this new kicker. The experimental setups for bandwidth and coaxial wire measurement of longitudinal coupling impedance and their corresponding test results will be reported. As a cross check, bead-pull measurement has also been done to verify the beam coupling measurement by coaxial wire method at the kicker center frequency. Longitudinal field profile of the accelerating mode along the beam path has also been mapped. High order cavity modes of the kicker have also been observed and their effects on the beam are evaluated.

  14. Application of multidimensional item response theory models to longitudinal data

    NARCIS (Netherlands)

    Marvelde, te Janneke M.; Glas, Cees A.W.; Van Landeghem, Georges; Van Damme, Jan

    2006-01-01

    The application of multidimensional item response theory (IRT) models to longitudinal educational surveys where students are repeatedly measured is discussed and exemplified. A marginal maximum likelihood (MML) method to estimate the parameters of a multidimensional generalized partial credit model

  15. Longitudinal Vibrations of Rheological Rod With Variable Cross Section

    Institute of Scientific and Technical Information of China (English)

    Katica(Stevanovic)HEDRIH; AleksandarFILIPOVSKI

    1999-01-01

    Longitudinal vibrations of rheological rod with variable cross section are examined.Particular solutions and eigenfunction are accomplished for natural vibrations of the rod with hereditary material of standard hereditary body.Some examples are given.

  16. Longitudinal Statistics for New Social Security Disability Insurance Beneficiaries

    OpenAIRE

    David Stapleton; Su Liu; Dawn Phelps; Sarah Prenovitz

    2010-01-01

    This paper presents the findings from a longitudinal examination regarding the extent to which new Social Security Disability Insurance beneficiaries return to work and use disability insurance work incentives, based on Social Security Administration data.

  17. Variable selection and estimation for longitudinal survey data

    KAUST Repository

    Wang, Li

    2014-09-01

    There is wide interest in studying longitudinal surveys where sample subjects are observed successively over time. Longitudinal surveys have been used in many areas today, for example, in the health and social sciences, to explore relationships or to identify significant variables in regression settings. This paper develops a general strategy for the model selection problem in longitudinal sample surveys. A survey weighted penalized estimating equation approach is proposed to select significant variables and estimate the coefficients simultaneously. The proposed estimators are design consistent and perform as well as the oracle procedure when the correct submodel was known. The estimating function bootstrap is applied to obtain the standard errors of the estimated parameters with good accuracy. A fast and efficient variable selection algorithm is developed to identify significant variables for complex longitudinal survey data. Simulated examples are illustrated to show the usefulness of the proposed methodology under various model settings and sampling designs. © 2014 Elsevier Inc.

  18. Longitudinal dispersion modeling in small streams

    Science.gov (United States)

    Pekarova, Pavla; Pekar, Jan; Miklanek, Pavol

    2014-05-01

    The environmental problems caused by the increasing of pollutant loads discharged into natural water bodies are very complex. For that reason the cognition of transport mechanism and mixing characteristics in natural streams is very important. The mathematical and numerical models have become very useful tools for solving the water management problems. The mathematical simulations based on numerical models of pollution mixing in streams can be used (for example) for prediction of spreading of accidental contaminant waves in rivers. The paper deals with the estimation of the longitudinal dispersion coefficients and with the numerical simulation of transport and transformation of accidental pollution in the small natural streams. There are different ways of solving problems of pollution spreading in open channels, in natural rivers. One of them is the hydrodynamic approach, which endeavours to understand and quantify the spreading phenomenon in a stream. The hydrodynamic models are based on advection-diffusion equation and the majority of them are one-dimensional models. Their disadvantage is inability to simulate the spread of pollution until complete dispersion of pollutant across the stream section is finished. Two-dimensional mixing models do not suffer from these limitations. On the other hand, the one-dimensional models are simpler than two-dimensional ones, they need not so much input data and they are often swifter. Three-dimensional models under conditions of natural streams are applicable with difficulties (or inapplicable) for their complexity and demands on accuracy and amount of input data. As there was mentioned above the two-dimensional models can be used also until complete dispersion of pollutant across the stream section is not finished, so we decided to apply the two-dimensional model SIRENIE. Experimental microbasin Rybarik is the part of the experimental Mostenik brook basin of IH SAS Bratislava. It was established as a Field Hydrological

  19. [Development of the right ear advantage in dichotic listening test: comparison of the findings by cross-sectional and longitudinal studies].

    Science.gov (United States)

    Hatta, T; Yamamoto, M; Hirose, T

    1990-12-01

    The right ear advantage in dichotic listening test for VCV word pairs was investigated using both longitudinal and cross-sectional methods with children whose age ranged from four to six. The degree of a right ear advantage and the population of those who showed a right ear advantage increased with age in the cross-sectional method. In the longitudinal method, however, the above findings could not be confirmed. These results suggest that the application of dichotic listening test may be inappropriate to young children.

  20. Statistical methods for longitudinal data with agricultural applications

    DEFF Research Database (Denmark)

    Anantharama Ankinakatte, Smitha

    The PhD study focuses on modeling two kings of longitudinal data arising in agricultural applications: continuous time series data and discrete longitudinal data. Firstly, two statistical methods, neural networks and generalized additive models, are applied to predict masistis using multivariate...... algorithm. This was found to compare favourably with the algorithm implemented in the well-known Beagle software. Finally, an R package to apply APFA models developed as part of the PhD project is described...

  1. Longitudinal control laws design for a flying wing aircraft

    OpenAIRE

    Zhu, Yan

    2012-01-01

    This research is concerned with the flight dynamic, pitch flight control and flying qualities assessment for the reference BWB aircraft. It aims to develop the longitudinal control laws which could satisfy the flying and handing qualities over the whole flight envelope with added consideration of centre of gravity (CG) variation. In order to achieve this goal, both the longitudinal stability augmentation system (SAS) and autopilot control laws are studied in this thesis. Usi...

  2. Longitudinal Stability Criteria for a Propeller-Driven Aircraft

    OpenAIRE

    Gil Iosilevskii

    2010-01-01

    The Routh criterion is used to assess longitudinal dynamic stability of a propeller-driven aircraft. Under a few plausible assumptions on possible ranges of the pertinent stability derivatives, it reduces to a pair of simple conditions imposing a traditional aft limit (the forward of the maneuver and the neutral-speed-stability points) on the center-of-gravity position and an upper limit on the longitudinal moment of inertia. It is demonstrated that most aircraft have sufficiently small inert...

  3. Longitudinal, degenerate, and transversal parametric oscillation in a photorefractive media

    DEFF Research Database (Denmark)

    Pedersen, H.C.; Johansen, P.M.

    1996-01-01

    We present a theoretical model of photorefractive parametric oscillation that covers, for the first time, to our knowledge, the occurrence of the whole spectrum of parametric processes from transversal over degenerate to longitudinal parametric oscillation. It is shown that inclusion of so......-called noneigenwaves is essential for completing the model. We report on the first experiment that shows the transition from transversal over degenerate to longitudinal parametric oscillation. The experimental observations agree well with the theoretical predictions....

  4. Longitudinal Statistics for New Supplemental Security Income Beneficiaries

    OpenAIRE

    Yonatan Ben-Shalom; David Stapleton; Dawn Phelps; Maura Bardos

    2012-01-01

    Using Social Security Administration data, this paper presents findings from a longitudinal analysis of the extent to which new Supplemental Security Income (SSI) disability beneficiaries return to work and use SSI work incentives. Longitudinal statistics show that more than 8 percent of those first awarded SSI benefits as adults in 2001 had their benefits suspended due to work for at least a month by December 2007.

  5. Longitudinal Beam Diagnostics for the ILC Injectors and Bunch Compressors

    Energy Technology Data Exchange (ETDEWEB)

    Piot, Philippe [Northern Illinois U.; Bracke, Adam [Northern Illinois U.; Demir, Veysel [Northern Illinois U.; Maxwell, Timothy [Fermilab; Rihaoui, Marwan [Argonne; Jing, Chunguang [Euclid Techlabs, Solon; Power, John [Argonne

    2010-12-01

    We present a diagnostics suite and analyze techniques for setting up the longitudinal beam dynamics in ILC e⁻ injectors and e⁺ and e⁻ bunch compressors. Techniques to measure the first order moments and recover the first order longitudinal transfer map of the injector's intricate bunching scheme are presented. Coherent transition radiation diagnostics needed to measure and monitor the bunch length downstream of the ~5 GeV bunch compressor are investigated using a vector diffraction model.

  6. Distribution of Longitudinal Inherent Strains in Multiple-passes Welding

    Institute of Scientific and Technical Information of China (English)

    Peng HE; Jiuhai ZHANG; Toshio Terasaki; Testuya Akiyama

    2001-01-01

    A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The computing method of distribution of longitudinal inherent strains in multiple-passes welding in heavy plate weldment is proposed. Distribution of longitudinal inherent strains in one-pass welding and two-passes welding are compared and analyzed. The effect of cutting on inherent strain is discussed.

  7. Longitudinal incision in surgical release of De Quervain disease.

    Science.gov (United States)

    Gundes, Hakan; Tosun, Bilgehan

    2005-09-01

    The objective of this paper is to contrast the use of a longitudinal incision in surgical decompression of De Quervain disease with a transverse incision. The advantages are ease in recognition of compartment variations and superficial branches of radial nerve and prevention of palmar tendon subluxation by permitting a more dorsal release of the compartment sheath. Since 2002, we have used a longitudinal skin incision instead of the classic transverse incision to release the first dorsal compartment.

  8. Transverse Mode Formation in Longitudinally Pumped Miniature Slab Lasers

    Institute of Scientific and Technical Information of China (English)

    XU Jian-Qiu; YE Xin; FANG Tao

    2006-01-01

    The formation of transverse modes in longitudinally pumped miniature slab lasers is investigated theoretically and experimentally. The longitudinally non-uniform gain-guiding is studied by expanding the electric field into the Hermite-Gaussian functions that satisfy boundary conditions of the resonator. Non-Gaussian transversal beam profiles in the near field are found and the beam diameter is reduced when the pump spot becomes smaller. The experimental observation agrees with the theoretical calculation.

  9. Spatial variation of the longitudinal dispersion coefficient in an estuary

    OpenAIRE

    D. C. Shaha; Y.-K. Cho; M.-T. Kwak; S. R. Kundu; K. T. Jung

    2011-01-01

    The effective longitudinal dispersion is a primary tool for determining property distributions in estuaries. Most previous studies have examined the longitudinal dispersion coefficient for the average tidal condition. However, information on spatial and temporal variations of this coefficient at low and high tide is scarce. Three years of hydrographic data taken at low and high tide along the main axis of the Sumjin River Estuary (SRE), Korea are used to estimate the spatial and temporal vari...

  10. Transverse and longitudinal angular momenta of light

    Energy Technology Data Exchange (ETDEWEB)

    Bliokh, Konstantin Y., E-mail: k.bliokh@gmail.com [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Nonlinear Physics Centre, RSPhysE, The Australian National University, Canberra, ACT 0200 (Australia); Nori, Franco [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Physics Department, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

    2015-08-26

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin  angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin–direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties.

  11. Global longitudinal strain: a useful everyday measurement?

    Directory of Open Access Journals (Sweden)

    A King

    2016-10-01

    Full Text Available Herceptin (Trastuzumab is a widely used and effective drug for the treatment of Her2+ breast cancer but its cardiotoxic side effects require regular monitoring by echocardiography. A 10% reduction in left ventricular ejection fraction can lead to suspension of treatment and therefore has significant implications for patient prognosis in terms of cardiac and cancer outcomes. Assessment of LV function by conventional 2D biplane method of discs (2DEF has limitations in accuracy and reproducibility. Global longitudinal strain (GLS is becoming more widely available and user friendly. It has been shown to demonstrate myocardial damage earlier in treatment than 2DEF, allowing the option of pharmacological intervention at a pre-clinical stage and preventing the interruption of Herceptin. This study compares the reproducibility of GLS with that of 2DEF in a routine clinical environment. Fifty echocardiograms performed on female patients undergoing Herceptin treatment were used to measure both 2DEF and GLS within the recommended standard appointment time of 40 min. The data were re-measured (blind by the same operator a minimum of 14 days later to determine intra-operator variation. These data were also measured by a second operator (blind, to assess inter-operator variation. Analysis by direct comparison, intra-class correlation (ICC, coefficient of variation (CV and Bland–Altman plots demonstrated that GLS is a more reproducible measurement than 2DEF. This is important to prevent clinical decisions being erroneously based on variation in operator measurement. The investigation also shows that with advances in machine software this is a practical addition to routine assessment rather than merely a research tool.

  12. Turbulent flow in longitudinally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.P.; Hirsa, A.; Jensen, M.K. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

    1996-09-01

    An experimental investigation of fully developed, steady, turbulent flow in longitudinally finned tubes has been performed. A two-channel, four-beam, laser-Doppler velocimeter was used to measure velocity profiles and turbulent statistics of air flow seeded with titanium dioxide particles. Mean velocities in axial, radial, and circumferential directions were measured over the tube cross sections and pressure drop in the tubes was measured at six stations along the test section length in order to calculate the fully developed friction factor. Four experimental tube geometries were studied: one smooth tube; two 8-finned tubes (fin height-to-radius ratios of 0.333 and 0.167), and one 16-finned tube (fin height-to-radius ratio of 0.167); detailed measurements were taken at air flow rates corresponding to Reynolds numbers of approximately 5,000, 25,000, and 50,000. Friction factor data were compared to literature results and showed good agreement for both smooth and finned tubes. The wall shear stress distribution varied significantly with reynolds number, particularly for Reynolds numbers of 25,000 and below. Maximum wall shear stress was found at the fin tip and minimum at the fin root. Four secondary flow cells were detected per fin (one in each interfin spacing and one in each core region for each fin); secondary flows were found to be small in comparison to the mean axial flow and relative magnitudes were unaffected by axial flow rate at Reynolds numbers above 25,000. The fluctuating velocities had a structure similar to that of the smooth tube in the core region while the turbulence in the interfin region was greatly reduced. The principal, primary shear stress distribution differed considerably from that of the smooth tube, particularly in the interfin region, and the orientation was found to be approximately in the same direction as the gradient of the mean axial velocity, supporting the use of an eddy viscosity formulation in turbulence modeling.

  13. Longitudinal fluctuations in the Berezinskii-Kosterlitz-Thouless phase

    Science.gov (United States)

    Jakubczyk, Pawel; Metzner, Walter

    2017-02-01

    We analyze the interplay of longitudinal and transverse thermal fluctuations in a U(1 ) symmetric two-dimensional ϕ4 theory. Toward this end, we derive coupled renormalization-group equations for both types of fluctuations obtained from a linear (Cartesian) decomposition of the order-parameter field. Discarding the longitudinal fluctuations, the expected Berezinskii-Kosterlitz-Thouless phase characterized by a finite stiffness and an algebraic decay of order-parameter correlations is recovered. Renormalized by transverse fluctuations, the longitudinal mass scales to zero so that longitudinal fluctuations become increasingly important for small momenta. Within our expansion of the effective action, they generate a logarithmic decrease of the stiffness, in agreement with previous functional renormalization-group calculations. The logarithmic terms imply a deviation from the vanishing β function for the stiffness in the nonlinear σ model describing the phase fluctuations at three-loop order. To gain further insight, we also compute the flow of the parameters characterizing longitudinal and transverse fluctuations from a density-phase representation of the order-parameter field, with a cutoff on phase fluctuations. The power-law flow of the longitudinal mass and other quantities is thereby confirmed, but the stiffness remains finite in this approach. We conclude that the marginal flow of the stiffness obtained in the Cartesian representation is an artifact of the truncated expansion of momentum dependences.

  14. Longitudinal changes in white matter microstructure after heavy cannabis use.

    Science.gov (United States)

    Becker, Mary P; Collins, Paul F; Lim, Kelvin O; Muetzel, R L; Luciana, M

    2015-12-01

    Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users and 23 age-, sex-, and IQ-matched non-using controls with limited substance use histories. Onset of cannabis use was prior to age 17. Cannabis users displayed reduced longitudinal growth in fractional anisotropy in the central and parietal regions of the right and left superior longitudinal fasciculus, in white matter adjacent to the left superior frontal gyrus, in the left corticospinal tract, and in the right anterior thalamic radiation lateral to the genu of the corpus callosum, along with less longitudinal reduction of radial diffusion in the right central/posterior superior longitudinal fasciculus, corticospinal tract, and posterior cingulum. Greater amounts of cannabis use were correlated with reduced longitudinal growth in FA as was relatively impaired performance on a measure of verbal learning. These findings suggest that continued heavy cannabis use during adolescence and young adulthood alters ongoing development of white matter microstructure, contributing to functional impairment.

  15. Detecting Change in Longitudinal Social Networks

    Science.gov (United States)

    2011-01-01

    marketing campaigns and media on social behavior. Initial Construct populations, social and knowledge networks, can be hypothetical or real (Carley...patent data bases, phone-networks, email- based-networks, social- media networks and more. Page 6 of 37 Current methods of change detection in...CUSUM C Sta measured fo o be successf Average Bet ct either incre or each socia g increases in the data for fective for ch ork. tistic Over Tim

  16. Key point in dermoscopic differentiation between early nail apparatus melanoma and benign longitudinal melanonychia

    OpenAIRE

    Koga, Hiroshi; Saida, Toshiaki; Uhara, Hisashi

    2011-01-01

    Longitudinal melanonychia presents in various conditions including neoplastic and reactive disorders. It is much more frequently seen in non-Caucasians than Caucasians. While most cases of nail apparatus melanoma start as longitudinal melanonychia, melanocytic nevi of the nail apparatus also typically accompany longitudinal melanonychia. Identifying the suspicious longitudinal melanonychia is therefore an important task for dermatologists. Dermoscopy provides useful information for making thi...

  17. A comparison of statistical methods for the discovery of genetic risk factors using longitudinal family study designs

    Directory of Open Access Journals (Sweden)

    Kelly M Burkett

    2015-11-01

    Full Text Available The etiology of immune-related diseases or traits is often complex, involving many genetic and environmental factors and their interactions. While methodological approaches focusing on an outcome measured at one time point have succeeded in identifying genetic factors involved in immune-related traits, they fail to capture complex disease mechanisms that fluctuate over time. It is increasingly recognized that longitudinal studies, where an outcome is measured at multiple time points, have great potential to shed light on complex disease mechanisms involving genetic factors. However, longitudinal data requires specialized statistical methods, especially in family studies where multiple sources of correlation in the data must be modeled. Using simulated data with known genetic effects, we examined the performance of different analytical methods for investigating associations between genetic factors and longitudinal phenotypes in twin data. The simulations were modeled on data from the Québec Newborn Twin Study, an ongoing population-based longitudinal study of twin births with multiple phenotypes, such as cortisol levels and body mass index, collected multiple times in infancy and early childhood and with sequencing data on immune-related genes and pathways. We compared approaches that we classify as (1 family-based methods applied to summaries of the observations over time, (2 longitudinal-based methods with simplifications of the familial correlation and (3 Bayesian family-based method with simplifications of the temporal correlation. We found that for estimation of the genetic main and interaction effects, all methods gave estimates close to the true values and had similar power. If heritability estimation is desired, approaches of type (1 also provide heritability estimates close to the true value. Our work shows that the simpler approaches are likely adequate to detect genetic effects; however, interpretation of these effects is more

  18. Striated populations in disordered environments with advection

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.; Succi, Sauro

    2017-01-01

    Growth in static and controlled environments such as a Petri dish can be used to study the spatial population dynamics of microorganisms. However, natural populations such as marine microbes experience fluid advection and often grow up in heterogeneous environments. We investigate a generalized Fisher-Kolmogorov-Petrovsky-Piscounov (FKPP) equation describing single species population subject to a constant flow field and quenched random spatially inhomogeneous growth rates with a fertile overall growth condition. We analytically and numerically demonstrate that the non-equilibrium steady-state population density develops a flow-driven striation pattern. The striations are highly asymmetric with a longitudinal correlation length that diverges linearly with the flow speed and a transverse correlation length that approaches a finite velocity-independent value. Linear response theory is developed to study the statistics of the steady states. Theoretical predictions show excellent agreement with the numerical steady states of the generalized FKPP equation obtained from Lattice Boltzmann simulations. These findings suggest that, although the growth disorder can be spatially uncorrelated, correlated population structures with striations emerge naturally at sufficiently strong advection.

  19. Education Vital Signs: Population.

    Science.gov (United States)

    Zakariya, Sally Banks

    1985-01-01

    Population changes and demographics shape the future of public schools. Includes statistics on ethnic makeup of student population, the projected baby boomlet, children of working mothers, households without children, and the aging population. (MD)

  20. Crecimiento longitudinal posnatal del primer metatarsiano. [Longitudinal postnatal growth of the first metatarsal bone

    Directory of Open Access Journals (Sweden)

    Julio J. Masquijo

    2014-10-01

    Full Text Available Introducción: si bien el crecimiento prenatal y posnatal del pie ha sido documentado hace varios años, el crecimiento longitudinal del primer metatarsiano en particular no ha sido estudiado previamente. El objetivo del estudio es determinar el patrón de crecimiento longitudinal posnatal de este hueso y compararlo con el del pie y los huesos largos del miembro inferior. Materiales y Métodos: mediante una búsqueda informatizada, se identificaron pacientes <18 años de edad con radiografías informadas como “normal” por el radiólogo. Se analizó una muestra de 886 pacientes divididos en 18 grupos según la edad (0-11 meses, 1 año, 2 años, etc. y el sexo. El análisis de las imágenes se realizó con un software de imágenes Kodak Carestream PACS. Resultados: el largo promedio en el primer grupo fue de 19,91 mm (3,20; 15,22-25,62. El largo promedio en el último grupo fue de 66,13 mm (5,33; 52,50-77,18. La tasa de crecimiento anual fue de 2,71 mm. La edad promedio al momento del cierre de la fisis fue de 14.85 años (± 1.64 para los varones y 14.77 años (± 3.63 para las niñas. Conclusión: el crecimiento del primer metatarsiano acompaña el crecimiento longitudinal del pie, pero no el de los huesos largos del miembro inferior. Las curvas de crecimiento del primer metatarsiano descritas en este artículo pueden ser aplicadas en patologías que afectan el desarrollo del pie o que requieren cirugía de corrección sobre el primer metatarsiano, o se las puede emplear como estándar de referencia en futuros estudios.

  1. Longitudinal nonlinear wave propagation through soft tissue.

    Science.gov (United States)

    Valdez, M; Balachandran, B

    2013-04-01

    In this paper, wave propagation through soft tissue is investigated. A primary aim of this investigation is to gain a fundamental understanding of the influence of soft tissue nonlinear material properties on the propagation characteristics of stress waves generated by transient loadings. Here, for computational modeling purposes, the soft tissue is modeled as a nonlinear visco-hyperelastic material, the geometry is assumed to be one-dimensional rod geometry, and uniaxial propagation of longitudinal waves is considered. By using the linearized model, a basic understanding of the characteristics of wave propagation is developed through the dispersion relation and in terms of the propagation speed and attenuation. In addition, it is illustrated as to how the linear system can be used to predict brain tissue material parameters through the use of available experimental ultrasonic attenuation curves. Furthermore, frequency thresholds for wave propagation along internal structures, such as axons in the white matter of the brain, are obtained through the linear analysis. With the nonlinear material model, the authors analyze cases in which one of the ends of the rods is fixed and the other end is subjected to a loading. Two variants of the nonlinear model are analyzed and the associated predictions are compared with the predictions of the corresponding linear model. The numerical results illustrate that one of the imprints of the nonlinearity on the wave propagation phenomenon is the steepening of the wave front, leading to jump-like variations in the stress wave profiles. This phenomenon is a consequence of the dependence of the local wave speed on the local deformation of the material. As per the predictions of the nonlinear material model, compressive waves in the structure travel faster than tensile waves. Furthermore, it is found that wave pulses with large amplitudes and small elapsed times are attenuated over shorter spans. This feature is due to the elevated

  2. LONGITUDINAL STUDIES OF MUSICALLY GIFTED SCHOOLGIRLS

    Directory of Open Access Journals (Sweden)

    Svetlana N. Loseva

    2016-01-01

    Full Text Available The aim of the article is to consider the empirical aspects of the development of musical gifted schoolgirls in vocal and choral activities.Methods. Scientific methods of research (observation, questionnaire, interview, formative experiment, longitude, testing are used. Data are analyzed using a complex of psychodiagnostic techniques: culture and free intelligence test by R. Cattell; the modified creative test by F. Williams; personal multifactorial questionnaire by R. Cattell. The reliability of the results and the validity of the findings is provided by the use of reliable and proven in the domestic and foreign psychology methods and techniques, using different statistical methods of data processing, the definition of parametric and non-parametric statistical tests (Student’s t-criterion, Spearman’s rank correlation, criterion U-Mann – Whitney, criterion T-Wilcoxon, L-criterion trends Page.Results and scientific novelty. Results of longitudinal research of development of musical aptitude are presented. Experimental work in which schoolgirls of 8–15 years participated, was carried out on the basis of creative choral collectives of Irkutsk within three years. Features of development of the pupils who are engaged in singing are revealed. It is established that in process of development of specially developed program (comprehension of emotional and semantic aspects of perception of a piece of music, finding of ability to distinguish musical timbres and the general coloring of sounding etc. analytical and intonation hearing improves under pupils’ age. Regular long singing trainings promote formation of cogitative operations: active development of divergent, rational and logical thinking and intelligence in general, and also acquisition of skills of a self-assessment. Besides, such occupations dispose children and teenagers to emotional responsiveness and spiritual self-improvement.Practical significance. The research

  3. Meeting the Challenges of Longitudinal Cluster-Based Trials in Schools: Lessons From the Chicago Trial of Positive Action.

    Science.gov (United States)

    Lewis, Kendra M; DuBois, David L; Ji, Peter; Day, Joseph; Silverthorn, Naida; Bavarian, Niloofar; Vuchinich, Samuel; Acock, Alan; Malloy, Margaret; Schure, Marc; Flay, Brian R

    2016-11-07

    We describe challenges in the 6-year longitudinal cluster randomized controlled trial (CRCT) of Positive Action (PA), a social-emotional and character development (SECD) program, conducted in 14 low-income, urban Chicago Public Schools. Challenges pertained to logistics of study planning (school recruitment, retention of schools during the trial, consent rates, assessment of student outcomes, and confidentiality), study design (randomization of a small number of schools), fidelity (implementation of PA and control condition activities), and evaluation (restricted range of outcomes, measurement invariance, statistical power, student mobility, and moderators of program effects). Strategies used to address the challenges within each of these areas are discussed. Incorporation of lessons learned from this study may help to improve future evaluations of longitudinal CRCTs, especially those that involve evaluation of school-based interventions for minority populations and urban areas.

  4. Measuring Executive Dysfunction Longitudinally and in Relation to Genetic Burden, Brain Volumetrics, and Depression in Prodromal Huntington Disease

    Science.gov (United States)

    Papp, Kathryn V.; Snyder, Peter J.; Mills, James A.; Duff, Kevin; Westervelt, Holly J.; Long, Jeffrey D.; Lourens, Spencer; Paulsen, Jane S.

    2013-01-01

    Executive dysfunction (ED) is a characteristic of Huntington disease (HD), but its severity and progression is less understood in the prodromal phase, e.g., before gross motor abnormalities. We examined planning and problem-solving abilities using the Towers Task in HD mutation-positive individuals without motor symptoms (n = 781) and controls (n = 212). Participants with greater disease progression (determined using mutation size and current age) performed more slowly and with less accuracy on the Towers Task. Performance accuracy was negatively related to striatal volume while both accuracy and working memory were negatively related to frontal white matter volume. Disease progression at baseline was not associated with longitudinal performance over 4 years. Whereas the baseline findings indicate that ED becomes more prevalent with greater disease progression in prodromal HD and can be quantified using the Towers task, the absence of notable longitudinal findings indicates that the Towers Task exhibits limited sensitivity to cognitive decline in this population. PMID:23246934

  5. A dynamic population-based model for the development of work-related respiratory health effects among bakery workers

    NARCIS (Netherlands)

    Warren, N.; Meijster, T.; Heederik, D.; Tielemans, E.

    2009-01-01

    Objectives: This paper presents a dynamic population-based model for the development of sensitisation and respiratory symptoms in bakery workers. The model simulates a population of individual workers longitudinally and tracks the development of work-related sensitisation and respiratory symptoms in

  6. A dynamic population-based model for the development of work-related respiratory health effects among bakery workers.

    NARCIS (Netherlands)

    Warren, N.; Meijster, T.; Heederik, D.; Tielemans, E.

    2009-01-01

    OBJECTIVES: This paper presents a dynamic population-based model for the development of sensitisation and respiratory symptoms in bakery workers. The model simulates a population of individual workers longitudinally and tracks the development of work-related sensitisation and respiratory symptoms in

  7. A Novel Longitudinal Atlas Construction Framework by Groupwise Registration of Subject Image Sequences

    OpenAIRE

    Liao, Shu; Jia, Hongjun; Wu, Guorong; Shen, Dinggang

    2011-01-01

    Longitudinal atlas construction is a challenging task in medical image analysis. Given a set of longitudinal images of different subjects, the task is how to construct the unbias longitudinal atlas sequence reflecting the anatomical changes over time. In this paper, a novel longitudinal atlas construction framework is proposed. The main contributions of the proposed method lie in the following aspects: (1) Subject-specific longitudinal information is captured by establishing a robust growth m...

  8. Dogslife: A web-based longitudinal study of Labrador Retriever health in the UK

    Directory of Open Access Journals (Sweden)

    Clements Dylan N

    2013-01-01

    Full Text Available Abstract Background Dogslife is the first large-scale internet-based longitudinal study of canine health. The study has been designed to examine how environmental and genetic factors influence the health and development of a birth cohort of UK-based pedigree Labrador Retrievers. Results In the first 12 months of the study 1,407 Kennel Club (KC registered eligible dogs were recruited, at a mean age of 119 days of age (SD 69 days, range 3 days – 504 days. Recruitment rates varied depending upon the study team’s ability to contact owners. Where owners authorised the provision of contact details 8.4% of dogs were recruited compared to 1.3% where no direct contact was possible. The proportion of dogs recruited was higher for owners who transferred the registration of their puppy from the breeder to themselves with the KC, and for owners who were sent an e-mail or postcard requesting participation in the project. Compliance with monthly updates was highly variable. For the 280 dogs that were aged 400 days or more on the 30th June 2011, we estimated between 39% and 45% of owners were still actively involved in the project. Initial evaluation suggests that the cohort is representative of the general population of the KC registered Labrador Retrievers eligible to enrol with the project. Clinical signs of illnesses were reported in 44.3% of Labrador Retrievers registered with Dogslife (median age of first illness 138 days, although only 44.1% of these resulted in a veterinary presentation (median age 316 days. Conclusions The web-based platform has enabled the recruitment of a representative population of KC registered Labrador Retrievers, providing the first large-scale longitudinal population-based study of dog health. The use of multiple different methods (e-mail, post and telephone of contact with dog owners was essential to maximise recruitment and retention of the cohort.

  9. Computer simulation model for the striped bass young-of-the-year population in the Hudson River. [Effects of entrainment and impingement at power plants on population dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Eraslan, A.H.; Van Winkle, W.; Sharp, R.D.; Christensen, S.W.; Goodyear, C.P.; Rush, R.M.; Fulkerson, W.

    1975-09-01

    This report presents a daily transient (tidal-averaged), longitudinally one-dimensional (cross-section-averaged) computer simulation model for the assessment of the entrainment and impingement impacts of power plant operations on young-of-the-year populations of the striped bass, Morone saxatilis, in the Hudson River.

  10. Social Determinants, Race, and Brain Health Outcomes: Findings from the Chicago Health and Aging Project.

    Science.gov (United States)

    Aggarwal, Neelum T; Everson-Rose, Susan A; Evans, Denis A

    2015-01-01

    The broad spectrum of economic and cultural diversity in the U.S. population correlates with and affects the study of behavioral aspects of health. The purpose of this article is to provide a selective overview of research findings from the Chicago Health and Aging Project (CHAP), which covers a socio-demographically diverse population in Chicago, with a focus on role-related psychosocial factors and observed racial/ethnic differences in aging outcomes. CHAP is a longitudinal, epidemiological study of common chronic conditions of aging with an emphasis on medical, psychosocial, and environmental risk factors for the decline in cognitive function across the older adult lifespan. We briefly summarize the study design and methods used in the CHAP study and characterize the study population and describe the psychosocial data, noting black-white associations as they relate to three common brain health outcomes: cognitive function and Alzheimer's Disease, stroke, and subclinical vascular disease as noted on neuroimaging.

  11. Longitudinal study of Thai people media exposure, knowledge, and behavior on dengue fever prevention and control.

    Science.gov (United States)

    Boonchutima, Smith; Kachentawa, Kirati; Limpavithayakul, Manasanun; Prachansri, Anan

    2017-03-09

    Dengue hemorrhagic fever is transmitted through a bite by a dengue -infected Aedes aegypti mosquito. It was first reported in the mid -20th century in Thailand, and since then its epidemiology has been of great concern and has spread all across the country. The alarming incidence of dengue posed a serious threat to human health in all major cities of Thailand. This study was aimed at identifying the level of awareness of dengue fever in Thai population knowledge for prevention and control, and most importantly contribution of media in educating masses for dengue control measures. It is longitudinal in nature and was conducted in 25 provinces of Thailand during 2013-2015. Approximately 7772 respondents participated in this study, with the selection of provinces based on considerations like population, prevalence and demography. A pre-tested structured questionnaire was used to collect information relevant to study participants' demographic profile, pre-existing knowledge about dengue fever and its reinforcement through media, and population attitudes toward prevention and control. Over the period of three years, a positive trend was revealed relevant to the contribution of media in educating and reminding the Thai population of dengue, without any uniformity or powerful campaigns. Based on the results drawn from this study, we conclude that despite the measures undertaken to prevent dengue fever, there is insufficient media exposure. An interdisciplinary approach involving the community participation, media, and government is needed to overcome dengue threat in Thailand.

  12. Etiological overlap between obsessive-compulsive disorder and anorexia nervosa: a longitudinal cohort, multigenerational family and twin study.

    Science.gov (United States)

    Cederlöf, Martin; Thornton, Laura M; Baker, Jessica; Lichtenstein, Paul; Larsson, Henrik; Rück, Christian; Bulik, Cynthia M; Mataix-Cols, David

    2015-10-01

    Obsessive-compulsive disorder (OCD) often co-occurs with anorexia nervosa (AN), a comorbid profile that complicates the clinical management of both conditions. This population-based study aimed to examine patterns of comorbidity, longitudinal risks, shared familial risks and shared genetic factors between OCD and AN at the population level. Participants were individuals with a diagnosis of OCD (N=19,814) or AN (N=8,462) in the Swedish National Patient Register between January 1992 and December 2009; their first-, second- and third-degree relatives; and population-matched (1:10 ratio) unaffected comparison individuals and their relatives. Female twins from the population-based Swedish Twin Register (N=8,550) were also included. Females with OCD had a 16-fold increased risk of having a comorbid diagnosis of AN, whereas males with OCD had a 37-fold increased risk. Longitudinal analyses showed that individuals first diagnosed with OCD had an increased risk for a later diagnosis of AN (risk ratio, RR=3.6), whereas individuals first diagnosed with AN had an even greater risk for a later diagnosis of OCD (RR=9.6). These longitudinal risks were about twice as high for males than for females. First- and second-degree relatives of probands with OCD had an increased risk for AN, and the magnitude of this risk tended to increase with the degree of genetic relatedness. Bivariate twin models revealed a moderate but significant degree of genetic overlap between self-reported OCD and AN diagnoses (ra =0.52, 95% CI: 0.26-0.81), but most of the genetic variance was disorder-specific. The moderately high genetic correlation supports the idea that this frequently observed comorbid pattern is at least in part due to shared genetic factors, though disorder-specific factors are more important. These results have implications for current gene-searching efforts and for clinical practice.

  13. Longitudinal study of urban malaria in a cohort of Ugandan children: description of study site, census and recruitment

    Directory of Open Access Journals (Sweden)

    Staedke Sarah G

    2006-03-01

    Full Text Available Abstract Background Studies of malaria in well-defined cohorts offer important data about the epidemiology of this complex disease, but few have been done in urban African populations. To generate a sampling frame for a longitudinal study of malaria incidence and treatment in Kampala, Uganda, a census, mapping and survey project was conducted. Methods All households in a geographically defined area were enumerated and mapped. Probability sampling was used to recruit a representative sample of children and collect baseline descriptive data for future longitudinal studies. Results 16,172 residents living in 4931 households in a densely-populated community (18,824 persons/km2 were enumerated. A total of 582 households were approached with at least one child less than 10 years of age in order to recruit 601 children living in 322 households. At enrollment, 19% were parasitaemic, 24% were anaemic, 43% used bednets, and 6% used insecticide-treated nets. Low G6PD activity (OR = 0.33, P = 0.009 and bednet use (OR = 0.64, P = 0.045 were associated with a decreased risk of parasitaemia. Increasing age (OR = 0.62 for each year, P Conclusion Detailed surveys of target populations in urban Africa can provide valuable descriptive data and provide a sampling frame for recruitment of representative cohorts for longitudinal studies. Plans to use a multi-disciplinary approach to improve the understanding of the distribution and determinants of malaria incidence and response to therapy in this population are discussed.

  14. Etiological overlap between obsessive-compulsive disorder and anorexia nervosa: a longitudinal cohort, multigenerational family and twin study

    Science.gov (United States)

    Cederlöf, Martin; Thornton, Laura M; Baker, Jessica; Lichtenstein, Paul; Larsson, Henrik; Rück, Christian; Bulik, Cynthia M; Mataix-Cols, David

    2015-01-01

    Obsessive-compulsive disorder (OCD) often co-occurs with anorexia nervosa (AN), a comorbid profile that complicates the clinical management of both conditions. This population-based study aimed to examine patterns of comorbidity, longitudinal risks, shared familial risks and shared genetic factors between OCD and AN at the population level. Participants were individuals with a diagnosis of OCD (N=19,814) or AN (N=8,462) in the Swedish National Patient Register between January 1992 and December 2009; their first-, second- and third-degree relatives; and population-matched (1:10 ratio) unaffected comparison individuals and their relatives. Female twins from the population-based Swedish Twin Register (N=8,550) were also included. Females with OCD had a 16-fold increased risk of having a comorbid diagnosis of AN, whereas males with OCD had a 37-fold increased risk. Longitudinal analyses showed that individuals first diagnosed with OCD had an increased risk for a later diagnosis of AN (risk ratio, RR=3.6), whereas individuals first diagnosed with AN had an even greater risk for a later diagnosis of OCD (RR=9.6). These longitudinal risks were about twice as high for males than for females. First- and second-degree relatives of probands with OCD had an increased risk for AN, and the magnitude of this risk tended to increase with the degree of genetic relatedness. Bivariate twin models revealed a moderate but significant degree of genetic overlap between self-reported OCD and AN diagnoses (ra=0.52, 95% CI: 0.26-0.81), but most of the genetic variance was disorder-specific. The moderately high genetic correlation supports the idea that this frequently observed comorbid pattern is at least in part due to shared genetic factors, though disorder-specific factors are more important. These results have implications for current gene-searching efforts and for clinical practice. PMID:26407789

  15. Social mobility and health in the Turin longitudinal study.

    Science.gov (United States)

    Cardano, Mario; Costa, Giuseppe; Demaria, Moreno

    2004-04-01

    One of the most controversial explanations of class inequalities in health is the health selection hypothesis or drift hypothesis which suggests there is a casual link between the health status of individuals and their chances of social mobility, both inter- and intra-generational. This study tests this hypothesis, and tries to answer three related questions: (a) to what extent does health status influence the chances of intra-generational mobility of individuals? (b) what is the impact on health inequalities of the various kinds of social mobility (both mobility in the labour market and exit from employment)-do they increase or reduce inequalities? (c) to what extent does health-related intra-generational social mobility contribute to the production of health inequalities? The data analysed in this paper were drawn from the records of the Turin Longitudinal Study, which was set up to monitor health inequality of the Turin population by combining census data, population registry records and medical records. Occupational mobility was observed during the decade 1981-1991. To evaluate the impact of the various processes of social mobility on health inequalities, mortality was observed over the period 1991-1999. The study population consists of men and women aged 25-49 at the beginning of mortality follow-up (1991), and registered as resident in Turin at both the 1981 and the 1991 censuses (N = 127,384). Health status was determined by observing hospital admission. For the purpose of the study healthy individuals were those with no hospital admissions during the period 1984-1986, while those admitted were classed as unhealthy. Social mobility in the labour market was measured via an interval data index of upward and downward movements on a scale of social desirability of occupations, designed for the Italian labour force via an empirical study carried out by de Lillo and Schizzerotto (La valutazione sociale delle occupazioni. Una scala di stratificazione occupazionale

  16. Nonsuicidal self-injury in adolescence: longitudinal course, trajectories, and intrapersonal predictors.

    Science.gov (United States)

    Barrocas, Andrea L; Giletta, Matteo; Hankin, Benjamin L; Prinstein, Mitchell J; Abela, John R Z

    2015-02-01

    Although prevalence rates of nonsuicidal self-injury (NSSI) has been established throughout adolescence, little is known about the progression of NSSI, and consequently, about the risk factors for youth NSSI engagement. This study aimed to describe the overall longitudinal course of NSSI and the latent trajectory classes of NSSI in a population-based sample of adolescents using multi-wave data. Moreover, this study examined whether sex, lifetime history of depression, rumination, and negative attributional style predicted the longitudinal course of NSSI and trajectory group membership. Participants were 617 Chinese adolescents in Grades 10 through 12 (51.4 % girls). NSSI was assessed across eight waves of data. History of depression, rumination, and negative attributional style were assessed at baseline. Latent growth curve modeling revealed that only lifetime depression predicted the longitudinal course of NSSI from Grades 10 to 12, with depressed adolescents showing greater and more stable NSSI engagement over time than non-depressed adolescents. Group-based trajectory modeling yielded three distinct trajectory classes of NSSI engagement: low (69.2 %), moderate (26.1 %), and chronic (4.7 %). Negative attributional style distinguished adolescents in the chronic vs. low and moderate NSSI trajectory classes. Sex, rumination, and lifetime depression predicted membership in the chronic and/or moderate vs. low NSSI trajectory class. NSSI trajectory classes, based on frequency of NSSI, exist and are differentiated by sex, depression history, rumination, and negative attributional style. This study suggests that during this period of adolescence NSSI may be a relatively stable behavior, especially for some adolescents. Negative attributional style may be a salient risk factor for chronic NSSI engagement.

  17. Physical Aggression and Language Ability from 17 to 72 months: Cross-lagged Effects in a Population Sample

    OpenAIRE

    Lisa-Christine Girard; Jean-Baptiste Pingault; Bruno Falissard; Michel Boivin; Ginette Dionne; Tremblay, Richard E

    2014-01-01

    Background: Does poor language ability in early childhood increase the likelihood of physical aggression or is language ability delayed by frequent physical aggression? This study examined the longitudinal associations between physical aggression and language ability from toddlerhood to early childhood in a population sample while controlling for parenting behaviours, non-verbal intellectual functioning, and children's sex. Methods: Children enrolled in the Quebec Longitudinal Study of Child ...

  18. Longitudinal mode structure in a non-planar ring resonator

    Directory of Open Access Journals (Sweden)

    M Jaberi

    2013-09-01

    Full Text Available  The structure of longitudinal modes of a passively Q-switched, non-planar unidirectional ring-resonator,with Nd:YAG active medium is described in this article. Two different techniques are used to study the longitudinal mode structure of the laser resonator. At first, the fast-fourier transform technique is applied for analyzing the mode beating of the optical fields by intensity frequency structure of the laser pulses to determine the number of longitudinal modes. Then, an analyzer etalon is used to observe Fabry-Perot fringes to compute the numbers of the resonator longitudinal modes. The results of two techniques are in good agreement with each other. Under the proper conditions, a reliable single longitudinal mode of the non-planar ring-resonator can be achieved with a good spatial mode profile that originates from the unidirectional travelling optical field propagation in the resonator having a very low sensitivity of the non-planar ring resonator to the optical elements misalignment.

  19. Relationships between longitudinal and radial Picea genera sound vibration parameters

    Institute of Scientific and Technical Information of China (English)

    SHEN Jun

    2006-01-01

    Longitudinal sawn wood are usually selected as samples in the study of sound properties of a musical instrument board.But in real production,radial sawn timber are cut and are also widely used as vibration component.Therefore,it is very important to evaluate the vibration properties of the board in the round,especially for the sound radiation characteristic of radial sawn timber and its relationship to longitudinal sawn timber.However,for the national and international experts,researches on radial sawn timber and its role and function in sound emission have not yet been developed.This paper describes a study of seven important spruces that grow up in the Sichuan and Heilongjiang provinces of China,and one Picea sitchensis specimen from North America.Under the high bending vibration mode,resonance frequency and other parameters of longitudinal and radial wood were tested.Analysis result disclosed the relationship between longitudinal and radial wood vibration property.An important conclusion of wood for musical instruments with proper anisotropy,fine toughness,and weak shear of longitudinal and radial vibration was inducted.

  20. Human Population Problems

    Science.gov (United States)

    Emmel, Thomas C.; Sligh, Michael M.

    1970-01-01

    Asserts that overpopulation is the most pressing world problem. Topics discussed include population control in primitive societies, population growth and control in modern societies, methods of motivational population control, consequences of no population control, and mass famines during the 1970's in underdeveloped countries. Cities 33…

  1. Understanding Rural Population Loss.

    Science.gov (United States)

    McGranahan, David A.; Beale, Calvin L.

    2002-01-01

    A quarter of nonmetro counties lost population in the 1990s, but population loss was not related to poverty rate or low educational levels, perhaps because low-skill workers can no longer expect better wages in urban areas. Population loss was related to low population density and remoteness (which decrease access to services), lack of natural…

  2. Why Population in 1974?

    Science.gov (United States)

    O'Connor, Marion

    1974-01-01

    Discusses the impact of world population growth leading to the establishment of the United Nations Fund for Population Activities and to the declaration of 1974 as World Population Year. Previews some of the parameters and interconnecting interests to be considered during this year of intensive population study. (JR)

  3. A learner developed longitudinal interprofessional education curriculum.

    Science.gov (United States)

    Fitzsimmons, Amber; Cisneros, Breanne; Samore, Jennifer

    2014-01-01

    Increased patient safety requires interprofessional collaboration, now critical given rising healthcare costs and an aging population with complex and chronic conditions. One way in which to educate future health care team members about team dynamics is to have them learn through active participation on a team. Six students representing the five health professions programs at the University of California, San Francisco formed a curriculum development team that created a novel yearlong interprofessional education curriculum and assessed its impact on knowledge, skills and attitudes of first-year learners in medicine, physical therapy, dentistry, nursing, and pharmacy (n = 480). Through their participation on the curriculum development team and reflection on their roles, responsibilities, communication and negotiation, the six students developed the inter-personal and intra-personal skills required for successful interprofessional collaboration.

  4. The Cognitive Processes underlying Affective Decision-making Predicting Adolescent Smoking Behaviors in a Longitudinal Study

    Directory of Open Access Journals (Sweden)

    Lin eXiao

    2013-10-01

    Full Text Available This study investigates the relationship between three different cognitive processes underlying the Iowa Gambling Task (IGT and adolescent smoking behaviors in a longitudinal study. We conducted a longitudinal study of 181 Chinese adolescents in Chengdu City, China. The participants were followed from 10th grade to 11th grade. When they were in the 10th grade (Time 1, we tested these adolescents’ decision-making using the Iowa Gambling Task and working memory capacity using the Self-ordered Pointing Test (SOPT. Self-report questionnaires were used to assess school academic performance and smoking behaviors. The same questionnaires were completed again at the one-year follow-up (Time 2. The Expectancy-Valence (EV Model was applied to distill the IGT performance into three different underlying psychological components: (i a motivational component which indicates the subjective weight the adolescents assign to gains versus losses; (ii a learning-rate component which indicates the sensitivity to recent outcomes versus past experiences; and (iii a response component which indicates how consistent the adolescents are between learning and responding. The subjective weight to gains vs. losses at Time 1 significantly predicted current smokers and current smoking levels at Time 2, controlling for demographic variables and baseline smoking behaviors. Therefore, by decomposing the IGT into three different psychological components, we found that the motivational process of weight gain vs. losses may serve as a neuropsychological marker to predict adolescent smoking behaviors in a general youth population.

  5. Describing the longitudinal course of major depression using Markov models: Data integration across three national surveys

    Directory of Open Access Journals (Sweden)

    Lee Robert C

    2005-11-01

    Full Text Available Abstract Background Most epidemiological studies of major depression report period prevalence estimates. These are of limited utility in characterizing the longitudinal epidemiology of this condition. Markov models provide a methodological framework for increasing the utility of epidemiological data. Markov models relating incidence and recovery to major depression prevalence have been described in a series of prior papers. In this paper, the models are extended to describe the longitudinal course of the disorder. Methods Data from three national surveys conducted by the Canadian national statistical agency (Statistics Canada were used in this analysis. These data were integrated using a Markov model. Incidence, recurrence and recovery were represented as weekly transition probabilities. Model parameters were calibrated to the survey estimates. Results The population was divided into three categories: low, moderate and high recurrence groups. The size of each category was approximated using lifetime data from a study using the WHO Mental Health Composite International Diagnostic Interview (WMH-CIDI. Consistent with previous work, transition probabilities reflecting recovery were high in the initial weeks of the episodes, and declined by a fixed proportion with each passing week. Conclusion Markov models provide a framework for integrating psychiatric epidemiological data. Previous studies have illustrated the utility of Markov models for decomposing prevalence into its various determinants: incidence, recovery and mortality. This study extends the Markov approach by distinguishing several recurrence categories.

  6. Effects of deployment on mental health in modern military forces: A review of longitudinal studies

    Directory of Open Access Journals (Sweden)

    Peter Nasveld

    2012-08-01

    Full Text Available Background. Earlier studies presenting evidence that operational deployment negatively affects mental health outcomes among military personnel and veterans generally have lacked conclusiveness, largely because of cross-sectional or retrospective design. Purpose. To review longitudinal studies investigating mental health outcomes of military personnel deployed in recent conflicts. Methods. MEDLINE database was searched using relevant keywords and MESH terms. The US Millennium Cohort study website was used to obtain the list of relevant publications. Only prospective longitudinal cohort studies investigating mental health outcomes in deployed post Vietnam era military or veteran populations of developed countries were included. Results. Eighteen studies fulfilled the inclusion criteria. Adverse effects included the increased incidence of post-deployment PTSD and depression. Individuals with the lowest functional scores and those exposed to previous traumatic assault were particularly vulnerable to a new onset of PTSD after combat exposure. Factors influencing the incidence of post-deployment PTSD included depression symptoms present during deployment, the presence of stress reaction during combat exposure and reception of associated frontline treatment, and the number of negative life events experienced after the traumatic event. More mental health problems were reported in soldiers returning from Iraq on the second screening conducted several months after their return, compared with the first screening immediately upon their return. Some mental health symptoms (anxiety and depression improved between deployments, while others (PTSD and panic attacks did not improve. CONCLUSION. The results indicate that combat exposure, not deployment in general , had an adverse effect on mental health.

  7. A note on prognostic accuracy evaluation of regression models applied to longitudinal autocorrelated binary data

    Directory of Open Access Journals (Sweden)

    Giulia Barbati

    2014-11-01

    Full Text Available Background: Focus of this work was on evaluating the prognostic accuracy of two approaches for modelling binary longitudinal outcomes, a Generalized Estimating Equation (GEE and a likelihood based method, Marginalized Transition Model (MTM, in which a transition model is combined with a marginal generalized linear model describing the average response as a function of measured predictors.Methods: A retrospective study on cardiovascular patients and a prospective study on sciatic pain were used to evaluate discrimination by computing the Area Under the Receiver-Operating-Characteristics curve, (AUC, the Integrated Discrimination Improvement (IDI and the Net Reclassification Improvement (NRI at different time occasions. Calibration was also evaluated. A simulation study was run in order to compare model’s performance in a context of a perfect knowledge of the data generating mechanism. Results: Similar regression coefficients estimates and comparable calibration were obtained; an higher discrimination level for MTM was observed. No significant differences in calibration and MSE (Mean Square Error emerged in the simulation study, that instead confirmed the MTM higher discrimination level. Conclusions: The choice of the regression approach should depend on the scientific question being addressed, i.e. if the overall population-average and calibration or the subject-specific patterns and discrimination are the objectives of interest, and some recently proposed discrimination indices are useful in evaluating predictive accuracy also in a context of longitudinal studies.

  8. Loss and gain cycles? A longitudinal study about burnout, engagement and self-efficacy

    Directory of Open Access Journals (Sweden)

    Susana Llorens-Gumbau

    2014-06-01

    Full Text Available The present longitudinal study (two waves, conducted on a population of 274 secondary-school teachers, expands on previous research on burnout and work engagement. Accordingly, the effect of organizational factors (obstacles, facilitators as well as personal resources (self-efficacy on burnout and engagement is tested longitudinally following the Social Cognitive Theory. More specifically, we test the loss and gain cycles, and reciprocal relationships concerning burnout, engagement, and self-efficacy over time. Four questions are addressed: (1 Are obstacles positively related to burnout and work self-efficacy over time? (2 Are facilitators positively related to engagement and self-efficacy over time? (3 Is work self-efficacy negatively related to burnout and obstacles over time? and (4 Is work self-efficacy positively related to engagement and facilitators over time? The results of a hard-copy survey carried out at two waves (8 months between the two times, which were computed on Structural Equation Modeling show that obstacles are positively related to burnout, which in turn is positively related to self-efficacy over time. Likewise, facilitators are positively related to engagement and self-efficacy, which in turn is positively related to facilitators over time. These findings suggest a positive gain cycle in which self-efficacy plays a central role.

  9. Longitudinal-bending mode micromotor using multilayer piezoelectric actuator.

    Science.gov (United States)

    Yao, K; Koc, B; Uchino, K

    2001-07-01

    Longitudinal-bending mode ultrasonic motors with a diameter of 3 mm were fabricated using stacked multilayer piezoelectric actuators, which were self-developed from hard lead zirconate titanate (PZT) ceramic. A bending vibration was converted from a longitudinal vibration with a longitudinal-bending coupler. The motors could be bidirectionally operated by changing driving frequency. Their starting and braking torque were analyzed based on the transient velocity response. With a load of moment of inertia 2.5 x 10(-7) kgm2, the motor showed a maximum starting torque of 127.5 microNm. The braking torque proved to be a constant independent on the motor's driving conditions and was roughly equivalent to the maximum starting torque achievable with our micromotors.

  10. Longitudinal jitter analysis of linear accelerator electron gun

    CERN Document Server

    Mingshan, Liu; Iqbal, Munawar

    2015-01-01

    We present measurement and analyses of longitudinal timing jitter of Beijing Electron Positron Collider (BEPCII) linear accelerator electron gun. We simulated longitudinal jitter effect of the gun using PARMELA about beam performance including beam profile, average energy, energy spread, longitudinal phase of reference particle and XY emittance. The maximum percentage difference of the beam parameters are calculated to be; 100%, 13.27%, 42.24%, 7.79% and 65.01%, 86.81%, respectively due to which the bunching efficiency is reduced to 54%. The simulation results are in agreement with test and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

  11. Longitudinal Magnetoresistance and "Chiral" Coupling in Silver Chalcogenides

    Institute of Scientific and Technical Information of China (English)

    XU Jie; ZHANG Duan-Ming

    2011-01-01

    A complex longitudinal magnetoresistance (MR∥) effect in the non-stoichiometric silver chalcogenides (include the silver selenide and telluride) has been found, however the mechanism for the MR∥ effect is not clear now.In this work, a new random resistor network for MR∥ effect is proposed based on the experimental observation. The network is constructed from six-terminal resistor units and the mobility of carries within the network has a Gaussian distribution. Considering the non-zero transverse-longitudinal coupling in materials, the resistance matrix of the sixterminal resistor unit is modified. It is found that the material has the "chiral" transverse-longitudinal couplings, which is suggested a main reason for the complex MR∥ effect. The model predictions are compared with the experimental results.A three dimension (3D) visualization of current flow within the network demonstrates the "current jets" phenomenon in the thickness of materials clearly.

  12. Longitudinal thermalization via the chromo-Weibel instability

    CERN Document Server

    Attems, Maximilian; Strickland, Michael

    2013-01-01

    Non-Abelian plasma instabilities play an important role in the non-equilibrium dynamics of a weakly coupled quark-gluon plasma. Using the discretized hard loop framework we calculate the time evolution of soft gluonic fields in a longitudinally free streaming background. Extrapolating our results to energies probed in relativistic heavy-ion collisions we find a pressure anisotropy that persists for a few fm/c. However, the chromofields quickly develop a Boltzmann longitudi- nal energy spectrum, suggesting fast longitudinal thermalization of the quark gluon plasma even though it remains momentum-space anisotropic. In this proceedings contribution we review our recent numerical results, present new results for the scaling of the isotropization time with the initial current fluctuation amplitude, and present tests of the gauge invariance of the extracted longitudinal spectra.

  13. Longitudinal evidence for diminished frontal cortex function in aging

    Science.gov (United States)

    Nyberg, Lars; Salami, Alireza; Andersson, Mikael; Eriksson, Johan; Kalpouzos, Grégoria; Kauppi, Karolina; Lind, Johanna; Pudas, Sara; Persson, Jonas; Nilsson, Lars-Göran

    2010-01-01

    Cross-sectional estimates of age-related changes in brain structure and function were compared with 6-y longitudinal estimates. The results indicated increased sensitivity of the longitudinal approach as well as qualitative differences. Critically, the cross-sectional analyses were suggestive of age-related frontal overrecruitment, whereas the longitudinal analyses revealed frontal underrecruitment with advancing age. The cross-sectional observation of overrecruitment reflected a select elderly sample. However, when followed over time, this sample showed reduced frontal recruitment. These findings dispute inferences of true age changes on the basis of age differences, hence challenging some contemporary models of neurocognitive aging, and demonstrate age-related decline in frontal brain volume as well as functional response. PMID:21156826

  14. Longitudinal intensity effects in the CERN Large Hadron Collider

    CERN Document Server

    AUTHOR|(CDS)2081238; Rivkin, Leonid

    This PhD thesis provides an improved knowledge of the LHC longitudinal impedance model and a better understanding of the longitudinal intensity effects. These effects can limit the LHC performance and lead to a reduction of the integrated luminosity. The LHC longitudinal impedance was measured with beams. Results obtained using traditional techniques are consistent with the expectations based on the impedance model, although the measurement precision was proven insufficient for the low impedance of the LHC. Innovative methods to probe the LHC reactive impedance were successfully used. One of the methods is based on exciting the beam with a sinusoidal rf phase modulation to estimate the synchrotron frequency shift from potential-well distortion. In the second method, the impedance is estimated from the loss of Landau damping threshold, which is also found to be in good agreement with analytical estimations. Beam-based impedance measurements agree well with estimations using the LHC impedance model. Macropartic...

  15. Stellar longitudinal magnetic field determination through multi-Zeeman signatures

    CERN Document Server

    Vélez, J C Ramírez; Navarro, S G; Córdova, J P; Sabin, L; Ruelas-Mayorga, A

    2016-01-01

    Context. A lot of effort has been put into the detection and determination of stellar magnetic fields using the spectral signal obtained from the combination of hundreds or thousands of individual lines, an approach known as multi-line techniques. However, so far most of multi-line techniques developed that retrieve stellar mean longitudinal magnetic fields recourse to sometimes heavy simplifications concerning line shapes and Zeeman splittings. Aims. To determine stellar longitudinal magnetic fields by means of the Principal Components Analysis and Zeeman Doppler Imaging (PCA-ZDI) multi-line technique, based on accurate polarised spectral line synthesis. Methods. In this paper we present the methodology to perform inversions of profiles obtained with PCA-ZDI. Results. Inversions with various magnetic geometries, field strengths and rotational velocities show that we can correctly determine the effective longitudinal magnetic field in stars using the PCA-ZDI method.

  16. Longitudinal tire force estimation based on sliding mode observer

    Energy Technology Data Exchange (ETDEWEB)

    El Hadri, A.; Cadiou, J.C.; M' Sirdi, N.K. [Versailles Univ., Paris (France). Lab. de Robotique; Beurier, G.; Delanne, Y. [Lab. Central des Ponts, Centre de Nantes (France)

    2001-07-01

    This paper presents an estimation method for vehicle longitudinal dynamics, particularly the tractive/braking force. The estimation can be used to detect a critical driving situation to improve security. It can be used also in several vehicle control systems. The main characteristics of the vehicle longitudinal dynamics were taken into account in the model used to design an observer and computer simulations. The state variables are the angular wheel velocity, vehicle velocity and the longitudinal tire force. The proposed differential equation of the tractive/braking force is derived using the concept of relaxation length. The observer designed is based on the sliding mode approach using only the angular wheel velocity measurement. The proposed method of estimation is verified through a one-wheel simulation model with a ''Magic formula'' tire model. Simulations results show an excellent reconstruction of the tire force. (orig.)

  17. Single Bunch Longitudinal Instability in the CERN SPS

    CERN Document Server

    Lasheen, Alexandre; Hancock, Steven; Radvilas, Edgaras; Roggen, Toon; Shaposhnikova, Elena

    2016-01-01

    The longitudinal single bunch instability observed in the SPS leads to uncontrolled emittance blow-up and limits the quality of high intensity beams required for the High Luminosity LHC and AWAKE projects at CERN. The present SPS impedance model developed from a thorough survey of machine elements was used in macro-particle simulations (with the code BLonD) of the bunch behavior through the acceleration cycle. Comparison of simulations with measurements of the synchrotron frequency shift, performed on the SPS flat bottom to probe the impedance, show a reasonable agreement. During extensive experimental studies various beam and machine parameters (bunch intensity, longitudinal emittance, RF voltage, with single and double RF systems) were scanned in order to further benchmark the SPS impedance model with measurements and to better understand the mechanism behind the instability. It was found that the dependence of instability threshold on longitudinal emittance and beam energy has an unexpected non-monotonic b...

  18. Nonlinear Cascade Strategy for Longitudinal Control of Electric Vehicle.

    Science.gov (United States)

    El Majdoub, K; Giri, F; Ouadi, H; Chaoui, F Z

    2014-01-01

    The problem of controlling the longitudinal motion of front-wheels electric vehicle (EV) is considered making the focus on the case where a single dc motor is used for both front wheels. Chassis dynamics are modelled applying relevant fundamental laws taking into account the aerodynamic effects and the road slope variation. The longitudinal slip, resulting from tire deformation, is captured through Kiencke's model. Despite its highly nonlinear nature the complete model proves to be utilizable in longitudinal control design. The control objective is to achieve a satisfactory vehicle speed regulation in acceleration/deceleration stages, despite wind speed and other parameters uncertainty. An adaptive controller is developed using the backstepping design technique. The obtained adaptive controller is shown to meet its objectives in presence of the changing aerodynamics efforts and road slope.

  19. Comparing Analytic Methods for Longitudinal GWAS and a Case-Study Evaluating Chemotherapy Course Length in Pediatric AML. A Report from the Children's Oncology Group.

    Science.gov (United States)

    Vujkovic, Marijana; Aplenc, Richard; Alonzo, Todd A; Gamis, Alan S; Li, Yimei

    2016-01-01

    Regression analysis is commonly used in genome-wide association studies (GWAS) to test genotype-phenotype associations but restricts the phenotype to a single observation for each individual. There is an increasing need for analytic methods for longitudinally collected phenotype data. Several methods have been proposed to perform longitudinal GWAS for family-based studies but few methods are described for unrelated populations. We compared the performance of three statistical approaches for longitudinal GWAS in unrelated subjectes: (1) principal component-based generalized estimating equations (PC-GEE); (2) principal component-based linear mixed effects model (PC-LMEM); (3) kinship coefficient matrix-based linear mixed effects model (KIN-LMEM), in a study of single-nucleotide polymorphisms (SNPs) on the duration of 4 courses of chemotherapy in 624 unrelated children with de novo acute myeloid leukemia (AML) genotyped on the Illumina 2.5 M OmniQuad from the COG studies AAML0531 and AAML1031. In this study we observed an exaggerated type I error with PC-GEE in SNPs with minor allele frequencies errors. PC-MEM showed balanced type I and type II errors for the observed vs. expected P-values in comparison to competing approaches. In general, a strong concordance was observed between the P-values with the different approaches, in particular among P errors, and yields high power. We therefore recommend PC-LMEM as a robust analytic approach for GWAS of longitudinal data in unrelated populations.

  20. Decorrelation of anisotropic flow along the longitudinal direction

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Long-Gang [Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Petersen, Hannah [Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Qin, Guang-You [Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Wuhan (China); Roy, Victor [Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Wang, Xin-Nian [Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Wuhan (China); Lawrence Berkeley National Laboratory, Nuclear Science Division MS70R0319, Berkeley, CA (United States)

    2016-04-15

    The initial energy density distribution and fluctuations in the transverse direction lead to anisotropic flow of final hadrons through collective expansion in high-energy heavy-ion collisions. Fluctuations along the longitudinal direction, on the other hand, can result in decorrelation of anisotropic flow in different regions of pseudorapidity (η). Decorrelation of the 2nd- and 3rd-order anisotropic flow with different η gaps for final charged hadrons in high-energy heavy-ion collisions is studied in an event-by-event (3+1)D ideal hydrodynamic model with fully fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The decorrelation is found to consist of both a linear twist and random fluctuation of the event plane angles. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation, indicating larger longitudinal fluctuations at lower beam energies. Our study also calls into question some of the current experimental methods for measuring anisotropic flow and the quantitative extraction of transport coefficients through comparisons to hydrodynamic simulations that do not include longitudinal fluctuations. (orig.)

  1. Decorrelation of anisotropic flow along the longitudinal direction

    Science.gov (United States)

    Pang, Long-Gang; Petersen, Hannah; Qin, Guang-You; Roy, Victor; Wang, Xin-Nian

    2016-04-01

    The initial energy density distribution and fluctuations in the transverse direction lead to anisotropic flow of final hadrons through collective expansion in high-energy heavy-ion collisions. Fluctuations along the longitudinal direction, on the other hand, can result in decorrelation of anisotropic flow in different regions of pseudorapidity ( η . Decorrelation of the 2nd- and 3rd-order anisotropic flow with different η gaps for final charged hadrons in high-energy heavy-ion collisions is studied in an event-by-event (3+1)D ideal hydrodynamic model with fully fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The decorrelation is found to consist of both a linear twist and random fluctuation of the event plane angles. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation, indicating larger longitudinal fluctuations at lower beam energies. Our study also calls into question some of the current experimental methods for measuring anisotropic flow and the quantitative extraction of transport coefficients through comparisons to hydrodynamic simulations that do not include longitudinal fluctuations.

  2. Residuals analysis of the generalized linear models for longitudinal data.

    Science.gov (United States)

    Chang, Y C

    2000-05-30

    The generalized estimation equation (GEE) method, one of the generalized linear models for longitudinal data, has been used widely in medical research. However, the related sensitivity analysis problem has not been explored intensively. One of the possible reasons for this was due to the correlated structure within the same subject. We showed that the conventional residuals plots for model diagnosis in longitudinal data could mislead a researcher into trusting the fitted model. A non-parametric method, named the Wald-Wolfowitz run test, was proposed to check the residuals plots both quantitatively and graphically. The rationale proposedin this paper is well illustrated with two real clinical studies in Taiwan.

  3. Positive illusions in marital relationships: a 13-year longitudinal study.

    Science.gov (United States)

    Miller, Paul J E; Niehuis, Sylvia; Huston, Ted L

    2006-12-01

    This study examined the long-term consequences of idealization in marriage, using both daily diary and questionnaire data collected from a sample of 168 newlywed couples who participated in a 4-wave, 13-year longitudinal study of marriage. Idealization was operationalized as the tendency for people to perceive their partner as more agreeable than would be expected based on their reports of their partner's agreeable and disagreeable behaviors. Spouses who idealized one another were more in love with each other as newlyweds. Longitudinal analyses suggested that spouses were less likely to suffer declines in love when they idealized one another as newlyweds. Newlywed levels of idealization did not predict divorce.

  4. Analysis of repeated outcome measures from longitudinal studies

    Institute of Scientific and Technical Information of China (English)

    Yuanjia WANG; Naihua DUAN

    2011-01-01

    @@ In many clinical studies repeated measurements of an outcome are collected over time.For example,in an 8-week study of treatment for obsessive compulsive disorder,the severity of the disorder may be measured weekly using the Yale-Brown-Obsessive-Compulsive-Disorder-Scale (YBOCS).For each study participant who completes the study,there will be nine repeated measures of YBOCS (a baseline assessment plus eight assessments during the course of treatment).Such a study in which participants are followed and measured repeatedly over time is called a longitudinal study and the resulting data are called longitudinal data.

  5. Measurement of Longitudinal Electron Diffusion in Liquid Argon

    CERN Document Server

    Li, Yichen; Thorn, Craig; Qian, Xin; Diwan, Milind; Joshi, Jyoti; Kettell, Steve; Morse, William; Rao, Triveni; Stewart, Jim; Tang, Wei; Viren, Brett

    2015-01-01

    We report the measurement of longitudinal electron diffusion coefficients in liquid argon for electric fields between 100 and 2000 V/cm with a gold photocathode as a bright electron source. The measurement principle, apparatus, and data analysis are described. Our results, which are consistent with previous measurements in the region between 100 to 350 V/cm [1] , are systematically higher than the prediction of Atrazhev-Timoshkin[2], and represent the world's best measurement in the region between 350 to 2000 V/cm. The quantum efficiency of the gold photocathode, the drift velocity and longitudinal diffusion coefficients in gas argon are also presented.

  6. Longitudinal vector form factors in weak decays of nuclei

    CERN Document Server

    Simkovic, F; Krivoruchenko, M I

    2015-01-01

    The longitudinal form factors of the weak vector current of particles with spin $ J = 1/2 $ and isospin $ I = 1/2 $ are determined by the mass difference and the charge radii of members of the isotopic doublets. The most promising reactions to measure these form factors are the reactions with large momentum transfers involving the spin-1/2 isotopic doublets with a maximum mass splitting. Numerical estimates of longitudinal form factors are given for nucleons and eight nuclear spin-1/2 isotopic doublets.

  7. A Longitudinal Study of Usability in Health Care

    DEFF Research Database (Denmark)

    Kjeldskov, Jesper; Skov, Mikael B.; Stage, Jan

    2010-01-01

    We report from a longitudinal laboratory-based usability evaluation of a health care information system. The purpose of the study was to inquire into the nature of usability problems experienced by novice and expert users, and to see to what extend usability problems of a health care information...... system may or may not disappear over time, as the nurses get more familiar with it-if time heals poor design? As our method for studying this, we conducted a longitudinal study with two key studies. A usability evaluation was conducted with novice users when an electronic patient record system was being......, we discuss implications for evaluating usability in health care....

  8. Frequency Dependence of Longitudinal Correlation Length in the Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    LI Feng-Hua; ZHANG Ren-He

    2008-01-01

    Spatial correlation coefficient is one of the most important parameters for the description of sound propagation in shallow water. Frequency dependence of the longitudinal correlation length is still an open topic. We observe in a shallow water experiment that the longitudinal correlation length in units of wavelength increases with the increase of frequency. This phenomenon has not been seen in the published papers. The theoretical analysis and numerical simulations indicate that the non-linear frequency relationship of the bottom attenuation is the main cause of this phenomenon.

  9. ROBUST ESTIMATION IN PARTIAL LINEAR MIXED MODEL FOR LONGITUDINAL DATA

    Institute of Scientific and Technical Information of China (English)

    Qin Guoyou; Zhu Zhongyi

    2008-01-01

    In this article, robust generalized estimating equation for the analysis of par- tial linear mixed model for longitudinal data is used. The authors approximate the non- parametric function by a regression spline. Under some regular conditions, the asymptotic properties of the estimators are obtained. To avoid the computation of high-dimensional integral, a robust Monte Carlo Newton-Raphson algorithm is used. Some simulations are carried out to study the performance of the proposed robust estimators. In addition, the authors also study the robustness and the efficiency of the proposed estimators by simulation. Finally, two real longitudinal data sets are analyzed.

  10. Longitudinal and cross-sectional changes with age in selected anthropometric and physiological traits in hospitalized adults: an insight from the Polish Longitudinal Study of Aging (PLSA

    Directory of Open Access Journals (Sweden)

    Chmielewski Piotr

    2015-12-01

    Full Text Available Longitudinal studies of aging concerning individuals with comparable lifestyle, diet, health profile, socioeconomic status, and income remain extraordinarily rare. The purposes of our ongoing project are as follows: (i to collect extensive data on biological and medical aspects of aging in the Polish population, (ii to determine factors affecting the rate and course of aging, (iii to understand how aging unfolds as a dynamic and malleable process in ontogeny, and (iv to find novel predictors of longevity. Our investigation followed 142 physically healthy asylum inmates, including 68 males and 74 females, for at least 25 years from the age of 45 years onward. Cross-sectional assessment involved 225 inmates, including 113 males and 112 females. All the patients lived for a very long time under similar and good environmental conditions at the hospital in Cibórz, Lubuskie Province. They maintained virtually the same daily schedule and lifestyle. The rate and direction of changes with age in selected anthropometric and physiological traits were determined using ANOVA, t-test, and regression analysis. There were sex differences in the rate and pattern of age-related changes in certain characteristics such as relative weight, red blood cell count, monocyte count, thymol turbidity value, systolic blood pressure, and body temperature. Body weight, the body mass index (BMI, and total bilirubin level increased with advancing age, while body height decreased with age in both sexes. In conclusion, the aging process was associated with many regressive alterations in biological traits in both sexes but the rate and pattern of these changes depended on biological factors such as age and sex. There were only few characteristics which did not change significantly during the period under study. On the basis of comparison between the pattern of longitudinal changes with aging and the pattern of cross-sectional changes with age in the analyzed traits, we were able

  11. Longitudinal effects of group music instruction on literacy skills in low-income children.

    Directory of Open Access Journals (Sweden)

    Jessica Slater

    Full Text Available Children from low-socioeconomic backgrounds tend to fall progressively further behind their higher-income peers over the course of their academic careers. Music training has been associated with enhanced language and learning skills, suggesting that music programs could play a role in helping low-income children to stay on track academically. Using a controlled, longitudinal design, the impact of group music instruction on English reading ability was assessed in 42 low-income Spanish-English bilingual children aged 6-9 years in Los Angeles. After one year, children who received music training retained their age-normed level of reading performance while a matched control group's performance deteriorated, consistent with expected declines in this population. While the extent of change is modest, outcomes nonetheless provide evidence that music programs may have value in helping to counteract the negative effects of low-socioeconomic status on child literacy development.

  12. Longitudinal effects of group music instruction on literacy skills in low-income children.

    Science.gov (United States)

    Slater, Jessica; Strait, Dana L; Skoe, Erika; O'Connell, Samantha; Thompson, Elaine; Kraus, Nina

    2014-01-01

    Children from low-socioeconomic backgrounds tend to fall progressively further behind their higher-income peers over the course of their academic careers. Music training has been associated with enhanced language and learning skills, suggesting that music programs could play a role in helping low-income children to stay on track academically. Using a controlled, longitudinal design, the impact of group music instruction on English reading ability was assessed in 42 low-income Spanish-English bilingual children aged 6-9 years in Los Angeles. After one year, children who received music training retained their age-normed level of reading performance while a matched control group's performance deteriorated, consistent with expected declines in this population. While the extent of change is modest, outcomes nonetheless provide evidence that music programs may have value in helping to counteract the negative effects of low-socioeconomic status on child literacy development.

  13. A longitudinal study of serum cobalamins and its binding proteins in lactating women

    DEFF Research Database (Denmark)

    Mørkbak, A L; Ramlau-Hansen, C H; Møller, U K;

    2006-01-01

    were analysed. RESULTS: No significant differences were observed in serum cobalamins or its binding proteins related to supplementation with vitamin B12 or the duration of lactation. Serum cobalamins remained unchanged from 3 weeks to 9 months post-partum. Total TC (holoTC) (median+/-s.e. pmol...... in HC during a 9-month period post-partum. No differences were observed between the vitamin B12-supplemented and the unsupplemented groups. Thus, supplementation with vitamin B12 has no impact on the circulating level of serum cobalamins or its binding proteins in a Danish population of lactating......OBJECTIVE: To examine longitudinal changes in serum cobalamins, transcobalamin (TC) and haptocorrin (HC) during lactation and to investigate the influence of vitamin B12 supplementation on these parameters. DESIGN: A 9-month follow-up study. SUBJECTS AND METHODS: Lactating mothers (N=89) including...

  14. Anxiety trajectories and identity development in adolescence: a five-wave longitudinal study.

    Science.gov (United States)

    Crocetti, Elisabetta; Klimstra, Theo; Keijsers, Loes; Hale, William W; Meeus, Wim

    2009-07-01

    The aim of this five-wave longitudinal study was to investigate the relationship between anxiety and adolescent identity development. Participants were 1,313 adolescents who annually completed measures of anxiety and identity. Growth Mixture Modeling (GMM) analyses demonstrated that the adolescent population was best typified by two latent growth trajectory classes: a low anxiety class (n = 1,199) characterized by a low initial level of anxiety that decreased over time and a high anxiety class (n = 114) characterized by a higher initial level of anxiety that increased over time. To answer our research question, we tested a model in which the anxiety classes predicted initial levels and rates of change of three identity dimensions: commitment, in-depth exploration, and reconsideration of commitment. Findings indicated that the high anxiety adolescents displayed a more troublesome identity development than their low anxiety peers, since their commitments became weaker with age, and they reconsidered them intensively.

  15. Does habitual physical activity prevent insomnia? A cross-sectional and longitudinal study of elderly Japanese.

    Science.gov (United States)

    Inoue, Sachiko; Yorifuji, Takashi; Sugiyama, Masumi; Ohta, Toshiki; Ishikawa-Takata, Kazuko; Doi, Hiroyuki

    2013-04-01

    Few epidemiological studies have examined the potential protective effects of physical activity on insomnia. The authors thus evaluated the association between physical activity and insomnia in a large population-based study in Shizuoka, Japan. Individual data were obtained from participants in an ongoing cohort study. A total of 14,001 older residents who completed questionnaires were followed for 3 yr. Of these, 10,211 and 3,697 participants were eligible for the cross-sectional and longitudinal analyses, respectively. The authors obtained information about the frequency of physical activity and insomnia. Then, the adjusted odds ratios and 95% confidence intervals between physical activity and insomnia were estimated. Habitual physical activity was related to lower prevalence of insomnia. Frequent physical activity also reduced the incidence of insomnia, especially difficulty maintaining sleep. For elderly people with sufficient mobility and no preexisting disease, high-frequency physical activity (e.g., 5 or more days/wk) may help reduce insomnia.

  16. Drinking Distilled. Onset, course and treatment of alcohol use disorders in the general population

    NARCIS (Netherlands)

    Tuithof, M.

    2015-01-01

    Although most people in Western society drink alcohol and regard this to be harmless and normal, some people drink excessively and develop an alcohol use disorder. This thesis examined the onset, course and treatment of alcohol use disorders in the general population using 3-year longitudinal data f

  17. Political and social determinants of life expectancy in less developed countries: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Lin Ro-Ting

    2012-01-01

    Full Text Available Abstract Background This study aimed to examine the longitudinal contributions of four political and socioeconomic factors to the increase in life expectancy in less developed countries (LDCs between 1970 and 2004. Methods We collected 35 years of annual data for 119 LDCs on life expectancy at birth and on four key socioeconomic indicators: economy, measured by log10 gross domestic product per capita at purchasing power parity; educational environment, measured by the literacy rate of the adult population aged 15 years and over; nutritional status, measured by the proportion of undernourished people in the population; and political regime, measured by the regime score from the Polity IV database. Using linear mixed models, we analyzed the longitudinal effects of these multiple factors on life expectancy at birth with a lag of 0-10 years, adjusting for both time and regional correlations. Results The LDCs' increases in life expectancy over time were associated with all four factors. Political regime had the least influence on increased life expectancy to begin with, but became significant starting in the 3rd year and continued to increase, while the impact of the other socioeconomic factors began strong but continually decreased over time. The combined effects of these four socioeconomic and political determinants contributed 54.74% - 98.16% of the life expectancy gains throughout the lag periods of 0-10 years. Conclusions Though the effect of democratic politics on increasing life expectancy was relatively small in the short term when compared to the effects of the other socioeconomic factors, the long-term impact of democracy should not be underestimated.

  18. A prospective, longitudinal study of growth, nutrition and sedentary behaviour in young children with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Weir Kelly A

    2010-04-01

    Full Text Available Abstract Background Cerebral palsy is the most common cause of physical disability in childhood, occurring in one in 500 children. It is caused by a static brain lesion in the neonatal period leading to a range of activity limitations. Oral motor and swallowing dysfunction, poor nutritional status and poor growth are reported frequently in young children with cerebral palsy and may impact detrimentally on physical and cognitive development, health care utilisation, participation and quality of life in later childhood. The impact of modifiable factors (dietary intake and physical activity on growth, nutritional status, and body composition (taking into account motor severity in this population is poorly understood. This study aims to investigate the relationship between a range of factors - linear growth, body composition, oral motor and feeding dysfunction, dietary intake, and time spent sedentary (adjusting for motor severity - and health outcomes, health care utilisation, participation and quality of life in young children with cerebral palsy (from corrected age of 18 months to 5 years. Design/Methods This prospective, longitudinal, population-based study aims to recruit a total of 240 young children with cerebral palsy born in Queensland, Australia between 1st September 2006 and 31st December 2009 (80 from each birth year. Data collection will occur at three time points for each child: 17 - 25 months corrected age, 36 ± 1 months and 60 ± 1 months. Outcomes to be assessed include linear growth, body weight, body composition, dietary intake, oral motor function and feeding ability, time spent sedentary, participation, medical resource use and quality of life. Discussion This protocol describes a study that will provide the first longitudinal description of the relationship between functional attainment and modifiable lifestyle factors (dietary intake and habitual time spent sedentary and their impact on the growth, body composition and

  19. [Genetic diversity based on swine leukocyte antigen complex mi-crosatellites(SLA-MS) in five pig populations].

    Science.gov (United States)

    Yu, Hui; Liu, Rong-Hui; Li, Hua; Zuo, Qi-Zhen; Li, Yan; Wu, Zhen-Fang

    2012-11-01

    The genetic diversity of swine leukocyte antigen complex (SLA) was studied among Guangdong local pigs, Huanan wild boars (S.s. chirodontus) and introduced pigs, which aimed at providing a theoretical foundation for further pig anti-disease resistance breeding. Pietrain pigs, Duroc pigs, Large black-white pigs, Lantang pigs, and Huanan wild boars were genotyped by employing 18 microsatellites in swine leukocyte antigen complex (SLA-MS). The result showed that the average diversity in SLA II was higher (He=0.628, PIC=0.581) than that in SLA I (He=0.530, PIC=0.474) and in SLA III (He=0.526, PIC=0.458). The molecular diversity indices (MDI) of Huanan wild boars was the highest(0.716), followed by Lantang pigs (0.614), Large black-white pigs (0.559), Pietrain pigs (0.550) and Duroc pigs (0.507). As a whole, the genetic diversity of Huanan wild boars was the highest over Guangdong native pigs and introduced pigs. Large black-white pigs and Duroc pigs had ever happened a severe bottleneck by comparison with the Garza-Williamson index (GWI) in Huanan wild boar. From the genetic distance, one clade was that Lantang pigs were first clustered with Huanan wild boar, and then grouped together with Large black-white pigs; another clade was that Pietrain pigs were independently clustered with Duroc pigs in the NJ tree. The results would establish the foundation for pig conservation of germplasm resource, disease resistance breeding, and multiplicative strains.

  20. Estimating hidden population size using Respondent-Driven Sampling data.

    Science.gov (United States)

    Handcock, Mark S; Gile, Krista J; Mar, Corinne M

    Respondent-Driven Sampling (RDS) is n approach to sampling design and inference in hard-to-reach human populations. It is often used in situations where the target population is rare and/or stigmatized in the larger population, so that it is prohibitively expensive to contact them through the available frames. Common examples include injecting drug users, men who have sex with men, and female sex workers. Most analysis of RDS data has focused on estimating aggregate characteristics, such as disease prevalence. However, RDS is often conducted in settings where the population size is unknown and of great independent interest. This paper presents an approach to estimating the size of a target population based on data collected through RDS. The proposed approach uses a successive sampling approximation to RDS to leverage information in the ordered sequence of observed personal network sizes. The inference uses the Bayesian framework, allowing for the incorporation of prior knowledge. A flexible class of priors for the population size is used that aids elicitation. An extensive simulation study provides insight into the performance of the method for estimating population size under a broad range of conditions. A further study shows the approach also improves estimation of aggregate characteristics. Finally, the method demonstrates sensible results when used to estimate the size of known networked populations from the National Longitudinal Study of Adolescent Health, and when used to estimate the size of a hard-to-reach population at high risk for HIV.

  1. Analyzing age-specific genetic effects on human extreme age survival in cohort-based longitudinal studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Jacobsen, Rune; Sørensen, Mette

    2013-01-01

    The analysis of age-specific genetic effects on human survival over extreme ages is confronted with a deceleration pattern in mortality that deviates from traditional survival models and sparse genetic data available. As human late life is a distinct phase of life history, exploring the genetic...... effects on extreme age survival can be of special interest to evolutionary biology and health science. We introduce a non-parametric survival analysis approach that combines population survival information with individual genotype data in assessing the genetic effects in cohort-based longitudinal studies...

  2. The role of self-efficacy on the relationship between the workplace environment and physical activity: a longitudinal mediation analysis.

    Science.gov (United States)

    Plotnikoff, Ronald C; Pickering, Michael A; Flaman, Laura M; Spence, John C

    2010-04-01

    Cross-sectional studies show that self-efficacy (SE) serves as a partial mediator of the effect that perceptions of workplace environment have on self-reported workplace physical activity (PA). To further explore the role SE plays in the relationship between perceptions of the workplace environment and workplace PA, cross-sectional mediation analyses were performed on adult employees at baseline (n = 897), 6 months (n = 616), and 12 months (n = 612); a longitudinal time-sequence was incorporated into the mediation model; and correlates of residual change version of the mediation were tested. The R (2) ranged from .05 to .08 for the three cross-sectional analyses, .03 for the longitudinal analyses, and from .02 to .03 for the residual analyses. The results from the residual change model analyses supported those of the cross-sectional and longitudinal analyses, suggesting the relationship between perceived workplace environment and PA was partially mediated by SE. Future research should include similar studies with different population groups and in different settings.

  3. Longitudinal study of serum placental GH in 455 normal pregnancies

    DEFF Research Database (Denmark)

    Chellakooty, Marla; Skibsted, Lillian; Skouby, Sven Olaf

    2002-01-01

    Placental GH is thought to be responsible for the rise in maternal IGF-I during pregnancy and is considered to be important for fetal growth. In this prospective longitudinal study of healthy pregnant women, we investigated determinants of placental GH in maternal serum. Serum was obtained from 4...

  4. Minor Delinquency and Immigration: A Longitudinal Study among Male Adolescents

    Science.gov (United States)

    Titzmann, Peter F.; Silbereisen, Rainer K.; Mesch, Gustavo

    2014-01-01

    On the basis of general theories of delinquency and the specific situation of immigrants, this longitudinal study investigated predictors of initial levels and rates of change in delinquency among 188 male ethnic German Diaspora immigrants from the former Soviet Union (FSU) in Germany, 237 male native German adolescents, and 182 male Jewish…

  5. Career Trajectories of Dutch Pop Musicians: A Longitudinal Study

    Science.gov (United States)

    Zwaan, Koos; ter Bogt, Tom F. M.; Raaijmakers, Quinten

    2010-01-01

    Systematic studies of artistic careers are scarce and this is the first large-scale study on the career development of pop musicians. Using a prospective longitudinal approach we followed a sample of aspiring pop musicians in the Netherlands (N=369) over a three-year period. First we identified four groups of pop musicians with different career…

  6. Longitudinal Evidence Linking Processing Speed to the Development of Reasoning

    Science.gov (United States)

    Kail, Robert V.; Lervåg, Arne; Hulme, Charles

    2016-01-01

    Age-related change in processing speed has been linked directly to increases in reasoning as well as indirectly via increases in the capacity of working memory (WM). Most of the evidence linking change in speed to reasoning has come from cross-sectional research; in this article we present the findings from a 2½-year longitudinal study of 277 6-…

  7. Conduct, Biological Factors and Adult Delinquency in a Longitudinal Perspective.

    Science.gov (United States)

    Magnusson, David

    In the course of a longitudinal research program conducted in Sweden, data were being collected on biological and psychological aspects of individual functioning and on environmental factors for a fairly large representative sample (approximately 1,000) of Swedish males and females between 10 and 27 years of age. Based on data from the…

  8. A Longitudinal Study of the Impact of an Environmental Action

    Science.gov (United States)

    Rioux, Liliane; Pasquier, Daniel

    2013-01-01

    In a previous study, we investigated the impact of an awareness-raising campaign on the behaviour of secondary school children in the Centre Region of France, regarding the recycling of used batteries. But, was it a question of pro-environmental behaviour or simply an environmental action? To answer this question, a three-year longitudinal study…

  9. Longitudinal Factor Score Estimation Using the Kalman Filter.

    Science.gov (United States)

    Oud, Johan H.; And Others

    1990-01-01

    How longitudinal factor score estimation--the estimation of the evolution of factor scores for individual examinees over time--can profit from the Kalman filter technique is described. The Kalman estimates change more cautiously over time, have lower estimation error variances, and reproduce the LISREL program latent state correlations more…

  10. Longitudinal wave motion in width-constrained auxetic plates

    Science.gov (United States)

    Lim, Teik-Cheng

    2016-05-01

    This paper investigates the longitudinal wave velocity in auxetic plates in comparison to conventional ones, in which the plate is constrained from motion in the width direction. By taking into account the thickness change of the plate and its corresponding change in density, the developed wave velocity is casted not only as a function of Young’s modulus and density, but also in terms of Poisson’s ratio and longitudinal strain. Results show that density and thickness variations compensate for one another when the Poisson’s ratio is positive, but add up when the Poisson’s ratio is negative. Results also reveal that the classical model of longitudinal wave velocity for the plate is accurate when the Poisson’s ratio is about 1/3; at this Poisson’s ratio the influence from density and thickness variations cancel each other. Comparison between the current corrected model and the density-corrected Rayleigh-Lamb model reveals a number of consistent trends, while the discrepancies are elucidated. If the plate material possesses a negative Poisson’s ratio, the deviation of the actual wave velocity from the classical model becomes significant; auxeticity suppresses and enhances the wave velocity in compressive and tensile impacts, respectively. Hence the use of the corrected model is proposed when predicting longitudinal waves in width-constrained auxetic plates, and auxetic materials can be harnessed for effectively controlling wave velocities in thin-walled structures.

  11. A Longitudinal Study of Children's Social Adjustment during Elementary School.

    Science.gov (United States)

    Battistich, Victor; Solomon, Daniel

    A 7-year, longitudinal study of children's social development from kindergarten through sixth grade was designed to identify unusually prosocial children and characteristics that differentiated them from average and antisocial peers. Another objective was to identify functional socioemotional predictors of changes in children's social adjustment.…

  12. Acquisition of English by Korean Children: A Longitudinal Analysis.

    Science.gov (United States)

    Lee, Eun-Joo

    1998-01-01

    Longitudinally investigated the development of interlanguage by two Korean speakers of English to better understand the second-language acquisition process. In particular it tested the aspect hypothesis that asserts that verb inflections in early interlanguage systems function primarily as markers of lexical aspect. (Author/VWL)

  13. Effects of Team and Organizational Commitment--A Longitudinal Study

    Science.gov (United States)

    Neininger, Alexandra; Lehmann-Willenbrock, Nale; Kauffeld, Simone; Henschel, Angela

    2010-01-01

    Retention management, i.e., keeping qualified employees, is a top priority for contemporary organizations. Commitment, and especially team commitment, can be the key to mastering this challenge. There is a lack of longitudinal research concerning the development and the direction of the effects of team commitment over time. In a longitudinal…

  14. Effects of organizational and team commitment - a longitudinal study.

    NARCIS (Netherlands)

    Neininger, A.; Lehmann-Willenbrock, N.K.; Kauffeld, S.; Henschel, A.

    2010-01-01

    Retention management, i.e., keeping qualified employees, is a top priority for contemporary organizations. Commitment, and especially teamcommitment, can be the key to mastering this challenge. There is a lack of longitudinal research concerning the development and the direction of the effects of te

  15. Longitudinal Study on Reciprocity between Personality Traits and Parenting Stress

    Science.gov (United States)

    Rantanen, Johanna; Tillemann, Kati; Metsäpelto, Riitta-Leena; Kokko, Katja; Pulkkinen, Lea

    2015-01-01

    Reciprocal associations between the Big Five personality traits and parenting stress--including both parents' feelings of their distress and perception of their incompetence as parents--were studied with 248 participants (49% of which were males). Longitudinal data, collected at ages 33/36, 42 and 50 years, were used. Cross-lagged path…

  16. Homeschooling Education: Longitudinal Study of Methods, Materials, and Curricula

    Science.gov (United States)

    Hanna, Linda G.

    2012-01-01

    In a comprehensive study of two-hundred fifty homeschooling families in urban, rural and suburban areas of the Commonwealth of Pennsylvania, the researcher examined all aspects of the instruction, materials and curricula employed by the families in a ten-year longitudinal study from 1998 through 2008. The researcher conducted interviews and…

  17. Giftedness, Trauma, and Development: A Qualitative, Longitudinal Case Study

    Science.gov (United States)

    Peterson, Jean Sunde

    2014-01-01

    A qualitative, longitudinal, phenomenological case study explored how a gifted female experienced various life events and aspects of development during adolescence and young adulthood (ages 15-30 years), particularly as related to multiple traumatic experiences, which were revealed late in the first year of the study. Additional experiences, well…

  18. The longitudinal controls fixed static stability of tailless aircraft

    OpenAIRE

    de Castro, Helena V.

    2000-01-01

    This paper describes the development of a simple theory of the longitudinal controls fixed static stability of tailless aeroplanes. The classical theory, as developed for the conventional aircraft, is modified to accommodate the particular features of the tailless aeroplanes. The theory was then applied to a particular blended-wing-body tailless civil transport aircraft, BWB-98. Cranfield University

  19. Longitudinal Changes in Disabled Husbands' and Wives' Receipt of Care

    Science.gov (United States)

    Noel-Miller, Claire

    2010-01-01

    Purpose of the Study: This study contrasts 2-year adjustments in disabled husbands' and wives' amount of received care following both worsening and recovery in personal (activities of daily living [ADLs]) and routine care (instrumental activities of daily living [IADLs]) disability. Design and Methods: Using longitudinal data on 789 husbands and…

  20. Advanced Issues in Propensity Scores: Longitudinal and Missing Data

    Science.gov (United States)

    Kupzyk, Kevin A.; Beal, Sarah J.

    2017-01-01

    In order to investigate causality in situations where random assignment is not possible, propensity scores can be used in regression adjustment, stratification, inverse-probability treatment weighting, or matching. The basic concepts behind propensity scores have been extensively described. When data are longitudinal or missing, the estimation and…

  1. Nonlinear Latent Curve Models for Multivariate Longitudinal Data

    Science.gov (United States)

    Blozis, Shelley A.; Conger, Katherine J.; Harring, Jeffrey R.

    2007-01-01

    Latent curve models have become a useful approach to analyzing longitudinal data, due in part to their allowance of and emphasis on individual differences in features that describe change. Common applications of latent curve models in developmental studies rely on polynomial functions, such as linear or quadratic functions. Although useful for…

  2. TOMOGRAPHIC MEASUREMENT OF LONGITUDINAL EMITTANCE GROWTH DUE TO STRIPPING FOILS.

    Energy Technology Data Exchange (ETDEWEB)

    MONTAG, C.; AHRENS, L.; THIEBERGER, P.

    2005-05-16

    During beam acceleration in the Brookhaven accelerator complex, heavy ions are stripped of their electrons in several steps. Depending on the properties of the stripping foils, this process results in an increased energy spread and longitudinal emittance growth. A tomographic phase space reconstruction technique has been applied to measure the associated emittance growth for different stripping foil materials.

  3. Phonological Awareness and Mathematical Difficulty: A Longitudinal Perspective

    Science.gov (United States)

    Jordan, Julie-Ann; Wylie, Judith; Mulhern, Gerry

    2010-01-01

    The present longitudinal study sought to investigate the impact of poor phonology on children's mathematical status. From a screening sample of 256 five-year-olds, 82 children were identified as either typically achieving (TA; N = 31), having comorbid poor phonology and mathematical difficulties (PDMD; N = 31), or having only poor phonology…

  4. Revisiting the Dedifferentiation Hypothesis with Longitudinal Multi-Cohort Data

    Science.gov (United States)

    de Frias, Cindy M.; Lovden, Martin; Lindenberger, Ulman; Nilsson, Lars-Goran

    2007-01-01

    The present longitudinal multi-cohort study examines whether interindividual variability in cognitive performance and change increases in old age, and whether associations among developments of different cognitive functions increase with adult age. Multivariate multiple-group latent growth modeling was applied to data from narrow cohorts separated…

  5. A Fresh Look at Longitudinal Standing Waves on a Spring

    Science.gov (United States)

    Rutherford, Casey

    2013-01-01

    Transverse standing waves produced on a string, as shown in Fig. 1, are a common demonstration of standing wave patterns that have nodes at both ends. Longitudinal standing waves can be produced on a helical spring that is mounted vertically and attached to a speaker, as shown in Fig. 2, and used to produce both node-node (NN) and node-antinode…

  6. Treatment of non-response in longitudinal network studies

    NARCIS (Netherlands)

    Huisman, Mark; Steglich, Christian

    2008-01-01

    The collection of longitudinal data on complete social networks often faces the problem of actor non-response. The resulting incomplete data pose a challenge to statistical analysis, as there typically is no natural way to treat the missing cases. This paper examines the problems caused by actors mi

  7. Children in care (CIC): A Danish longitudinal study

    DEFF Research Database (Denmark)

    Egelund, Tine; Hestbæk, Anne-Dorthe

    This paper presents results describing what characterizes young, Danish children in care and their parents, and, furthermore, discusses social policy implications of the complex psychosocial disadvantages influencing the families. The paper is based on a longitudinal study of all Danish children,...... collection newcomers into care from the 1995 cohort will be included in the sample....

  8. Exploring Intensive Longitudinal Measures of Student Engagement in Blended Learning

    Science.gov (United States)

    Henrie, Curtis R.; Bodily, Robert; Manwaring, Kristine C.; Graham, Charles R.

    2015-01-01

    In this exploratory study we used an intensive longitudinal approach to measure student engagement in a blended educational technology course, collecting both self-report and observational data. The self-report measure included a simple survey of Likert-scale and open-ended questions given repeatedly during the semester. Observational data were…

  9. Exploring Student-Teacher Interactions in Longitudinal Achievement Data

    Science.gov (United States)

    Lockwood, J. R.; McCaffrey, Daniel F.

    2009-01-01

    This article develops a model for longitudinal student achievement data designed to estimate heterogeneity in teacher effects across students of different achievement levels. The model specifies interactions between teacher effects and students' predicted scores on a test, estimating both average effects of individual teachers and interaction…

  10. Accelerated Brain Aging in Schizophrenia : A Longitudinal Pattern Recognition Study

    NARCIS (Netherlands)

    Schnack, Hugo G; van Haren, Neeltje E M; Nieuwenhuis, Mireille; Hulshoff Pol, Hilleke E; Cahn, Wiepke; Kahn, René S

    2016-01-01

    OBJECTIVE: Despite the multitude of longitudinal neuroimaging studies that have been published, a basic question on the progressive brain loss in schizophrenia remains unaddressed: Does it reflect accelerated aging of the brain, or is it caused by a fundamentally different process? The authors used

  11. Accelerated brain aging in schizophrenia : A longitudinal pattern recognition study

    NARCIS (Netherlands)

    Schnack, Hugo G.; Van Haren, Neeltje E M; Nieuwenhuis, Mireille; Pol, Hilleke E Hulshoff; Cahn, Wiepke; Kahn, René S.

    2016-01-01

    OBJECTIVE: Despite the multitude of longitudinal neuroimaging studies that have been published, a basic question on the progressive brain loss in schizophrenia remains unaddressed: Does it reflect accelerated aging of the brain, or is it caused by a fundamentally different process? The authors used

  12. Predictors of Adolescent Breakfast Consumption: Longitudinal Findings from Project EAT

    Science.gov (United States)

    Bruening, Meg; Larson, Nicole; Story, Mary; Neumark-Sztainer, Dianne; Hannan, Peter

    2011-01-01

    Objective: To identify predictors of breakfast consumption among adolescents. Methods: Five-year longitudinal study Project EAT (Eating Among Teens). Baseline surveys were completed in Minneapolis-St. Paul schools and by mail at follow-up by youth (n = 800) transitioning from middle to high school. Linear regression models examined associations…

  13. A Longitudinal Investigation of Commitment Dynamics in Cohabiting Relationships

    Science.gov (United States)

    Rhoades, Galena K.; Stanley, Scott M.; Markman, Howard J.

    2012-01-01

    This longitudinal study followed 120 cohabiting, opposite-sex couples over 8 months to test hypotheses derived from commitment theory about how two types of commitment (dedication and constraint) operate during cohabitation. In nearly half the couples, there were large differences between partners in terms of dedication. These differences were…

  14. Longitudinal static-field model for HD lasers

    Science.gov (United States)

    Baets, R.; Lagasse, P. E.

    1984-01-01

    A new static model for double-heterostructure lasers is presented which can take into account longitudinal effects in the cavity. The model makes use of the beam-propagation method to calculate the field propagation through the lasing waveguide structure.

  15. Left ventricular global longitudinal strain in acute myocardial infarction

    DEFF Research Database (Denmark)

    Ersbøll, Mads

    Systolic dysfunction, clinical heart failure and elevated levels of neurohormonal peptides are major predictors of adverse outcome after acute myocardial infarction (MI). In the present thesis we evaluated global longitudinal strain (GLS) in patients with acute MI in relation to neurohormonal...

  16. Modeling Longitudinal Dynamics in the Fermilab Booster Synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Ostiguy, Jean-Francois [Fermilab; Bhat, Chandra [Fermilab; Lebedev, Valeri [Fermilab

    2016-06-01

    The PIP-II project will replace the existing 400 MeV linac with a new, CW-capable, 800 MeV superconducting one. With respect to current operations, a 50% increase in beam intensity in the rapid cycling Booster synchrotron is expected. Booster batches are combined in the Recycler ring; this process limits the allowed longitudinal emittance of the extracted Booster beam. To suppress eddy currents, the Booster has no beam pipe; magnets are evacuated, exposing the beam to core laminations and this has a substantial impact on the longitudinal impedance. Noticeable longitudinal emittance growth is already observed at transition crossing. Operation at higher intensity will likely necessitate mitigation measures. We describe systematic efforts to construct a predictive model for current operating conditions. A longitudinal only code including a laminated wall impedance model, space charge effects, and feedback loops is developed. Parameter validation is performed using detailed measurements of relevant beam, rf and control parameters. An attempt is made to benchmark the code at operationally favorable machine settings.

  17. Longitudinal Construct Validity of Brief Symptom Inventory Subscales in Schizophrenia

    Science.gov (United States)

    Long, Jeffrey D.; Harring, Jeffrey R.; Brekke, John S.; Test, Mary Ann; Greenberg, Jan

    2007-01-01

    Longitudinal validity of Brief Symptom Inventory subscales was examined in a sample (N = 318) with schizophrenia-related illness measured at baseline and every 6 months for 3 years. Nonlinear factor analysis of items was used to test graded response models (GRMs) for subscales in isolation. The models varied in their within-time and between-times…

  18. Genetics and Genomics of Longitudinal Lung Function Patterns in Asthmatics

    NARCIS (Netherlands)

    McGeachie, Michael J; Yates, Katherine P; Zhou, Xiaobo; Guo, Feng; Sternberg, Alice L; Van Natta, Mark L; Wise, Robert A; Szefler, Stanley J; Sharma, Sunita; Kho, Alvin T; Cho, Michael H; Croteau-Chonka, Damien C; Castaldi, Peter J; Jain, Gaurav; Sanyal, Amartya; Zhan, Ye; Lajoie, Bryan R; Dekker, Job; Stamatoyannopoulos, John; Covar, Ronina A; Zeiger, Robert S; Adkinson, N Franklin; Williams, Paul V; Kelly, H William; Grasemann, Hartmut; Vonk, Judith M; Koppelman, Gerard H; Postma, Dirkje S; Raby, Benjamin A; Houston, Isaac; Lu, Quan; Fuhlbrigge, Anne L; Tantisira, Kelan G; Silverman, Edwin K; Tonascia, James; Strunk, Robert C; Weiss, Scott T

    2016-01-01

    RATIONALE: Patterns of longitudinal lung function growth and decline in childhood asthma have been shown to be important in determining risk for future respiratory ailments including chronic airway obstruction and chronic obstructive pulmonary disease (COPD). OBJECTIVES: To determine the genetic und

  19. Sex Differences in the Longitudinal Prediction of Adult Personality.

    Science.gov (United States)

    Sutton-Smith, B.; Rosenberg, B. G.

    This paper deals with two sets of data-one that fails to find any long-term sex differences in adults, and another which seems to find such differences. The Berkeley Guidance Study offers longitudinal data in which no variables differentiate between the two sexes at all age levels. From these results, the authors conclude that the normal course of…

  20. Longitudinal correlates of change in blood pressure in adolescent girls

    NARCIS (Netherlands)

    Daniels, [No Value; McMahon, RP; Obarzanek, E; Waclawiw, MA; Similo, SL; Biro, FM; Schreiber, GB; Kimm, SYS; Morrison, JA; Barton, BA

    1998-01-01

    The objective of this study was to assess the longitudinal changes in blood pressure in black and white adolescent girls and evaluate potential determinants of changes in blood pressure, including sexual maturation and body size. A total of 1213 black and 1166 white girls, ages 9 or 10 years at stud