Aquatic community structure in Mediterranean edge-of-field waterbodies as explained by environmental factors and the presence of pesticide mixtures.

PubMed

Pereira, Ana Santos; Dâmaso-Rodrigues, Maria Luísa; Amorim, Ana; Daam, Michiel A; Cerejeira, Maria José

2018-06-16

Studies addressing the predicted effects of pesticides in combination with abiotic and biotic factors on aquatic biota in ditches associated with typical Mediterranean agroecosystems are scarce. The current study aimed to evaluate the predicted effects of pesticides along with environmental factors and biota interactions on macroinvertebrate, zooplankton and phytoplankton community compositions in ditches adjacent to Portuguese maize and tomato crop areas. Data was analysed with the variance partitioning procedure based on redundancy analysis (RDA). The total variance in biological community composition was divided into the variance explained by the multi-substance potentially affected fraction [(msPAF) arthropods and primary producers], environmental factors (water chemistry parameters), biotic interactions, shared variance, and unexplained variance. The total explained variance reached 39.4% and the largest proportion of this explained variance was attributed to msPAF (23.7%). When each group (phytoplankton, zooplankton and macroinvertebrates) was analysed separately, biota interactions and environmental factors explained the largest proportion of variance. Results of this study indicate that besides the presence of pesticide mixtures, environmental factors and biotic interactions also considerably influence field freshwater communities. Subsequently, to increase our understanding of the risk of pesticide mixtures on ecosystem communities in edge-of-field water bodies, variations in environmental and biological factors should also be considered.

An examination of multilevel factors that may explain gender differences in children's physical activity.

PubMed

Crespo, Noe C; Corder, Kirsten; Marshall, Simon; Norman, Gregory J; Patrick, Kevin; Sallis, Jim F; Elder, John P

2013-09-01

Girls are less physically active than boys, yet no single study has examined the factors that may explain gender differences in children's physical activity (PA). This study was a cross-sectional analysis of data from 116 caregivers and their children aged 5-8 years who participated in the MOVE study. Caregivers reported various factors that may relate to children's PA (eg, encouragement for child PA and PA equipment at home). Child PA was measured by 7-day accelerometry. Linear regression tested for the variance in moderate-to-vigorous physical activity (MVPA) explained by gender and several variables. Gender and ethnicity interactions were examined. Caregivers were mostly female (97%), mean age 38 ± 6 years, mean BMI 28 ± 6 (kg/m2). Child's mean age was 8.1 ± 0.7, 54% were female and 40% were overweight/obese. Girls were less physically active than boys (54.1 ± 19.7 vs. 65.2 ± 28.0 daily minutes of MVPA, respectively). Among girls, more days of PE/week was associated with greater MVPA. Among boys, greater parent support for PA, greater parent modeling for PA, and greater number of PA equipment in the home were associated with greater MVPA. This study supports that boys and girls have different correlates for MVPA, which may partly explain gender differences in PA.

Mediating Factors Explaining the Association Between Sexual Minority Status and Dating Violence.

PubMed

Martin-Storey, Alexa; Fromme, Kim

2017-08-01

Dating violence presents a serious threat for individual health and well-being. A growing body of literature suggests that starting in adolescence, individuals with sexual minority identities (e.g., individuals who identify as gay, lesbian, or bisexual) may be at an increased risk for dating violence compared with heterosexuals. Research has not, however, identified the mechanisms that explain this vulnerability. Using a diverse sample of young adults ( n = 2,474), the current study explored how minority stress theory, revictimization theory, sex of sexual partners, and risky sexual behavior explained differences in dating violence between sexual minority and heterosexual young adults. Initial analyses suggested higher rates of dating violence among individuals who identified as bisexual, and individuals who identified as gay or lesbian when compared with heterosexuals, and further found that these associations failed to differ across gender. When mediating and control variables were included in the analyses, however, the association between both sexual minority identities and higher levels of dating violence became nonsignificant. Of particular interest was the role of discrimination, which mediated the association between bisexual identity and dating violence. Other factors, including sex and number of sexual partners, alcohol use, and childhood maltreatment, were associated with higher rates of dating violence but did not significantly explain vulnerability among sexual minority individuals compared with their heterosexual peers. These findings suggest the importance of minority stress theory in explaining vulnerability to dating violence victimization among bisexuals in particular, and generally support the importance of sexual-minority specific variables in understanding risk for dating violence within this vulnerable population.

Parents of children with cancer: which factors explain differences in health-related quality of life.

PubMed

Klassen, Anne F; Raina, Parminder; McIntosh, Cameron; Sung, Lillian; Klaassen, Robert J; O'Donnell, Maureen; Yanofsky, Rochelle; Dix, David

2011-09-01

Research with parents of children with cancer has identified factors related to their adjustment and coping, but it is not fully understood why some parents do well and others do not. Guided by a stress process model, we examined the interrelationships among a comprehensive set of factors to identify the most important determinants of health-related quality of life (HRQoL) in parents of children in active treatment for cancer. A cross-sectional survey of 411 parents (80% response rate) of children receiving cancer treatment in Canada was conducted between November 2004 and February 2007. The following constructs were measured: background and context factors, child characteristics, family-centered service delivery, caregiver strain, intrapsychic factors, coping/supportive factors and parental HRQoL. The model was evaluated using structural equation modeling. Analysis was stratified by time since diagnosis (i.e., <12 months and ≥12 months). For those within 12 months of their child's diagnosis, family-centred service provision, caregiver strain, and self-perception accounted for 58% of the variation in psychosocial health, whereas caregiver strain and social support explained 50% of the variation in physical health. For parents in the >12 month group, caregiving strain was the only factor with a direct relationship with parental psychosocial and physical health, accounting for 66% and 55% of the variance in these constructs, respectively. Our findings reinforce the need for health professionals to be particularly attuned to family caregivers in the early stages of treatment and identify potential areas for interventions to promote parental health. Copyright © 2010 UICC.

Explaining IT Professionals' Organizational Commitment Based on Age, Gender, and Personality Trait Factor

ERIC Educational Resources Information Center

Syed, Javaid A.

2017-01-01

The purpose of the present study was to test the Emotional Stability dimension of the Big Five factors of personality traits theory to predict or explain a relationship with Employee Organizational Commitment, when the relationship between Emotional Stability (ES) and Employee Organizational Commitment (EOC) was moderated by Gender and AgeGroup.…

Urban form and psychosocial factors: do they interact for leisure-time walking?

PubMed

Beenackers, Mariëlle A; Kamphuis, Carlijn B M; Prins, Richard G; Mackenbach, Johan P; Burdorf, Alex; van Lenthe, Frank J

2014-02-01

This cross-sectional study uses an adaptation of a social-ecological model on the hierarchy of walking needs to explore direct associations and interactions of urban-form characteristics and individual psychosocial factors for leisure-time walking. Questionnaire data (n = 736) from adults (25-74 yr) and systematic field observations within 14 neighborhoods in Eindhoven (the Netherlands) were used. Multilevel logistic regression models were used to relate the urban-form characteristics (accessibility, safety, comfort, and pleasurability) and individual psychosocial factors (attitude, self-efficacy, social influence, and intention) to two definitions of leisure-time walking, that is, any leisure-time walking and sufficient leisure-time walking according to the Dutch physical activity norm and to explore their interactions. Leisure-time walking was associated with psychosocial factors but not with characteristics of the urban environment. For sufficient leisure-time walking, interactions between attitude and several urban-form characteristics were found, indicating that positive urban-form characteristics contributed toward leisure-time walking only in residents with a less positive attitude toward physical activity. In contrast, living in a neighborhood that was accessible for walking was stronger associated with leisure-time walking among residents who experienced a positive social influence to engage in physical activity compared with those who reported less social influence. This study showed some evidence for an interaction between the neighborhood environment and the individual psychosocial factors in explaining leisure-time walking. The specific mechanism of interaction may depend on the specific combination of psychosocial factor and environmental factor. The lack of association between urban form and leisure-time walking could be partly due to the little variation in urban-form characteristics between neighborhoods.

Host‐related factors explaining interindividual variability of carotenoid bioavailability and tissue concentrations in humans

PubMed Central

Desmarchelier, Charles; Dragsted, Lars O.; Nielsen, Charlotte S.; Stahl, Wilhelm; Rühl, Ralph; Keijer, Jaap; Borel, Patrick

2017-01-01

Carotenoid dietary intake and their endogenous levels have been associated with a decreased risk of several chronic diseases. There are indications that carotenoid bioavailability depends, in addition to the food matrix, on host factors. These include diseases (e.g. colitis), life‐style habits (e.g. smoking), gender and age, as well as genetic variations including single nucleotide polymorphisms that govern carotenoid metabolism. These are expected to explain interindividual differences that contribute to carotenoid uptake, distribution, metabolism and excretion, and therefore possibly also their association with disease risk. For instance, digestion enzymes fostering micellization (PNLIP, CES), expression of uptake/efflux transporters (SR‐BI, CD36, NPC1L1), cleavage enzymes (BCO1/2), intracellular transporters (FABP2), secretion into chylomicrons (APOB, MTTP), carotenoid metabolism in the blood and liver (LPL, APO C/E, LDLR), and distribution to target tissues such as adipose tissue or macula (GSTP1, StARD3) depend on the activity of these proteins. In addition, human microbiota, e.g. via altering bile‐acid concentrations, may play a role in carotenoid bioavailability. In order to comprehend individual, variable responses to these compounds, an improved knowledge on intra‐/interindividual factors determining carotenoid bioavailability, including tissue distribution, is required. Here, we highlight the current knowledge on factors that may explain such intra‐/interindividual differences. PMID:28101967

Attempting to physically explain space-time correlation of extremes

NASA Astrophysics Data System (ADS)

Bernardara, Pietro; Gailhard, Joel

2010-05-01

Spatial and temporal clustering of hydro-meteorological extreme events is scientific evidence. Moreover, the statistical parameters characterizing their local frequencies of occurrence show clear spatial patterns. Thus, in order to robustly assess the hydro-meteorological hazard, statistical models need to be able to take into account spatial and temporal dependencies. Statistical models considering long term correlation for quantifying and qualifying temporal and spatial dependencies are available, such as multifractal approach. Furthermore, the development of regional frequency analysis techniques allows estimating the frequency of occurrence of extreme events taking into account spatial patterns on the extreme quantiles behaviour. However, in order to understand the origin of spatio-temporal clustering, an attempt to find physical explanation should be done. Here, some statistical evidences of spatio-temporal correlation and spatial patterns of extreme behaviour are given on a large database of more than 400 rainfall and discharge series in France. In particular, the spatial distribution of multifractal and Generalized Pareto distribution parameters shows evident correlation patterns in the behaviour of frequency of occurrence of extremes. It is then shown that the identification of atmospheric circulation pattern (weather types) can physically explain the temporal clustering of extreme rainfall events (seasonality) and the spatial pattern of the frequency of occurrence. Moreover, coupling this information with the hydrological modelization of a watershed (as in the Schadex approach) an explanation of spatio-temporal distribution of extreme discharge can also be provided. We finally show that a hydro-meteorological approach (as the Schadex approach) can explain and take into account space and time dependencies of hydro-meteorological extreme events.

Identifying context factors explaining physician's low performance in communication assessment: an explorative study in general practice.

PubMed

Essers, Geurt; van Dulmen, Sandra; van Weel, Chris; van der Vleuten, Cees; Kramer, Anneke

2011-12-13

Communication is a key competence for health care professionals. Analysis of registrar and GP communication performance in daily practice, however, suggests a suboptimal application of communication skills. The influence of context factors could reveal why communication performance levels, on average, do not appear adequate. The context of daily practice may require different skills or specific ways of handling these skills, whereas communication skills are mostly treated as generic. So far no empirical analysis of the context has been made. Our aim was to identify context factors that could be related to GP communication. A purposive sample of real-life videotaped GP consultations was analyzed (N = 17). As a frame of reference we chose the MAAS-Global, a widely used assessment instrument for medical communication. By inductive reasoning, we analyzed the GP behaviour in the consultation leading to poor item scores on the MAAS-Global. In these cases we looked for the presence of an intervening context factor, and how this might explain the actual GP communication behaviour. We reached saturation after having viewed 17 consultations. We identified 19 context factors that could potentially explain the deviation from generic recommendations on communication skills. These context factors can be categorized into doctor-related, patient-related, and consultation-related factors. Several context factors seem to influence doctor-patient communication, requiring the GP to apply communication skills differently from recommendations on communication. From this study we conclude that there is a need to explicitly account for context factors in the assessment of GP (and GP registrar) communication performance. The next step is to validate our findings.

Socioeconomic factors explain racial disparities in invasive community-associated methicillin-resistant Staphylococcus aureus disease rates

PubMed Central

See, Isaac; Wesson, Paul; Gualandi, Nicole; Dumyati, Ghinwa; Harrison, Lee H.; Lesher, Lindsey; Nadle, Joelle; Petit, Susan; Reisenauer, Claire; Schaffner, William; Tunali, Amy; Mu, Yi; Ahern, Jennifer

2017-01-01

Introduction Invasive community-associated methicillin-resistant Staphylococcus aureus (MRSA) incidence in the United States is higher among black persons than white persons. We explored the extent to which socioeconomic factors might explain this racial disparity. Methods A retrospective cohort was based on CDC’s Emerging Infections Program surveillance data for invasive community-associated MRSA cases (isolated from a normally sterile site of an outpatient or on hospital admission day ≤3 in a patient without specified major healthcare exposures) from 2009–2011 in 33 counties of 9 states. We used generalized estimating equations to determine census tract-level factors associated with differences in MRSA incidence and inverse odds ratio weighted mediation analysis to determine the proportion of racial disparity mediated by socioeconomic factors. Results Annual invasive community-associated MRSA incidence was 4.59/100,000 among whites and 7.60/100,000 among blacks (rate ratio: 1.66, 95% CI, 1.52–1.80). In the mediation analysis, after accounting for census tract-level measures of federally-designated medically underserved areas, education, income, housing value, and rural status, 91% of the original racial disparity was explained; no significant association of black race with community-associated MRSA remained (rate ratio: 1.05, 95% CI, 0.92–1.20). Conclusions The racial disparity in invasive community-associated MRSA rates was almost entirely mediated by socioeconomic factors. The specific factors that underlie the association between tract-level socioeconomic measures and MRSA incidence, which may include modifiable social (e.g., poverty, crowding) and biological factors (not explored in this analysis), should be elucidated to define strategies for reducing racial disparities in community-associated MRSA rates. PMID:28362911

Explaining the impact of poverty on old-age frailty in Europe: material, psychosocial and behavioural factors.

PubMed

Stolz, Erwin; Mayerl, Hannes; Waxenegger, Anja; Freidl, Wolfgang

2017-12-01

Previous research found poverty to be associated with adverse health outcomes among older adults but the factors that translate low economic resources into poor physical health are not well understood. The goal of this analysis was to assess the impact of material, psychosocial, and behavioural factors as well as education in explaining the poverty-health link. In total, 28 360 observations from 11 390 community-dwelling respondents (65+) in the Survey of Health, Ageing and Retirement in Europe (2004-13, 10 countries) were analysed. Multilevel growth curve models were used to assess the impact of combined income and asset poverty risk on old-age frailty (frailty index) and associated pathway variables. In total, 61.8% of the variation of poverty risk on frailty level was explained by direct and indirect effects. Results stress the role of material and particularly psychosocial factors such as perceived control and social isolation, whereas the role of health behaviour was negligible. We suggest to strengthen social policy and public health efforts in order to fight poverty and its deleterious health effects from early age on as well as to broaden the scope of interventions with regard to psychosocial factors. © The Author 2017. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Associations between factors within the home setting and screen time among children aged 0–5 years: a cross-sectional study

PubMed Central

2012-01-01

Background Excessive engagement in screen time has several immediate and long-term health implications among pre-school children. However, little is known about the factors that influence screen time in this age group. Therefore, the purpose of this study was to use the Ecologic Model of Sedentary Behavior as a guide to examine associations between intrapersonal, interpersonal, and physical environment factors within the home setting and screen time among pre-school children. Methods Participants were 746 pre-school children (≤ 5 years old) from the Kingston, Ontario, Canada area. From May to September, 2011, parents completed a questionnaire regarding several intrapersonal (child demographics), interpersonal (family demographics, parental cognitions, parental behavior), and physical environment (television, computer, or video games in the bedroom) factors within the home setting. Parents also reported the average amount of time per day their child spent watching television and playing video/computer games. Associations were examined using linear and logistic regression models. Results Most participants (93.7%) watched television and 37.9% played video/computer games. Several intrapersonal, interpersonal, and physical environment factors within the home setting were associated with screen time. More specifically, age, parental attitudes, parental barriers, parental descriptive norms, parental screen time, and having a television in the bedroom were positive predictors of screen time; whereas, parental education, parental income, and parental self-efficacy were negative predictors of screen time in the linear regression analysis. Collectively these variables explained 64.2% of the variance in screen time. Parental cognitive factors (self-efficacy, attitudes, barriers, descriptive norms) at the interpersonal level explained a large portion (37.9%) of this variance. Conclusions A large proportion of screen time in pre-school children was explained by factors

Risk factors cannot explain the higher prevalence rates of precancerous colorectal lesions in men

PubMed Central

Waldmann, Elisabeth; Heinze, Georg; Ferlitsch, Arnulf; GessI, Irina; Sallinger, Daniela; Jeschek, Philip; Britto-Arias, Martha; Salzl, Petra; Fasching, Elisabeth; Jilma, Bernd; Kundi, Michael; Trauner, Michael; Ferlitsch, Monika

2016-01-01

Background: Prevalence of (pre)cancerous colorectal lesions are higher in men than in women, although transition rates from advanced lesions to cancer is similar in both sexes. Our aim was to investigate whether the sex-specific difference in incidence of premalignant colorectal lesions might be explained by the impact of risk factors. Methods: A cross-sectional study analysing health check-up examinations and screening colonoscopies performed within a national quality assurance program. Results: A total of 25 409 patients were included in this study, 50.8% were women. Median age for both sexes was 60 years (interquartile range (IQR) 54–67). A multivariable model showed that risk factors mediated only 0.6 of the 10.4% gender gap in adenoma and 0.47 of the 3.2% gender gap in advanced adenoma detection rate. Smoking was the only independent risk factor with a varying sex-specific effect (men OR 1.46, CI 1.29, 1.64, women OR 1.76, CI 1.53, 2.06) and advanced adenomas (men OR 1.06, CI 0.80–1.42; women OR 2.08, CI 1.52–2.83). Independent risk factors for adenomas were BMI (OR 1.35 per IQR, CI 1.25–1.47) and triglyceride level (OR 1.03 per IQR, CI 1.00–1.06); for advanced adenomas physical activity (none vs regular: OR 1.54, CI 1.18–2.00, occasional vs regular: OR 1.17, CI 1.00–1.38), cholesterol level (OR 1.13 per IQR, CI 1.02–1.25), blood glucose level (OR 1.05 per IQR, CI 1.01–1.09) and alcohol score (OR 1.09 per IQR, CI 1.01–1.18). Conclusions: Risk factors cannot explain higher prevalence rates in men. Results of this study strongly underline the need for sex-specific screening recommendations. PMID:27764840

Could Trends in Time Children Spend with Parents Help Explain the Black-White Gap in Human Capital? Evidence from the American Time Use Survey

ERIC Educational Resources Information Center

Patterson, Richard W.

2017-01-01

It is widely believed that the time children spend with parents significantly impacts human capital formation. If time varies significantly between black and white children, this may help explain the large racial gap in test scores and wages. In this study, I use data from the American Time Use Survey to examine the patterns in the time black and…

To what extent is the familial risk of rheumatoid arthritis explained by established rheumatoid arthritis risk factors?

PubMed

Jiang, Xia; Frisell, Thomas; Askling, Johan; Karlson, Elizabeth W; Klareskog, Lars; Alfredsson, Lars; Källberg, Henrik

2015-02-01

Family history of rheumatoid arthritis (RA) is one of the strongest risk factors for developing RA, and information on family history is, therefore, routinely collected in clinical practice. However, as more genetic and environmental risk factors shared by relatives are identified, the importance of family history may diminish. The aim of this study was to determine how much of the familial risk of RA can be explained by established genetic and nongenetic risk factors. History of RA among first-degree relatives of individuals in the Epidemiological Investigation of Rheumatoid Arthritis case-control study was assessed through linkage to the Swedish Multigeneration Register and the Swedish Patient Register. We used logistic regression models to investigate the decrease in familial risk after successive adjustment for combinations of nongenetic risk factors (smoking, alcohol intake, parity, silica exposure, body mass index, fatty fish consumption, and education), and genetic risk factors (shared epitope [SE] and 76 single-nucleotide polymorphisms [SNPs]). Established nongenetic risk factors did not explain familial risk of either seropositive or seronegative RA to any significant degree. Genetic risk factors accounted for a limited proportion of the familial risk of seropositive RA (unadjusted odds ratio [OR] 4.10, SE-adjusted OR 3.72, SNP-adjusted OR 3.46, and SE and SNP-adjusted OR 3.35). Established risk factors only provided an explanation for familial risk of RA in minor part, suggesting that many (familial) risk factors remain to be identified, in particular for seronegative RA. Family history of RA therefore remains an important clinical risk factor for RA, the value of which has not yet been superseded by other information. There is thus a need for further etiologic studies of both seropositive and seronegative RA. Copyright © 2015 by the American College of Rheumatology.

Explaining outputs of primary health care: population and practice factors.

PubMed Central

Baker, D; Klein, R

1991-01-01

OBJECTIVE--To examine whether variations in the activities of general practice among family health service authorities can be explained by the populations characteristics and the organisation and resourcing of general practice. DESIGN--The family health services authorities were treated as discrete primary health care systems. Nineteen performance indicators reflecting the size, distribution, and characteristics of the population served; the organisation of general practice (inputs); and the activities generated by general practitioners and their staff (output) were analysed by stepwise regression. SETTING--90 family health services authorities in England. MAIN OUTCOME MEASURES--Rates of cervical smear testing, immunisation, prescribing, and night visiting. RESULTS--53% of the variation in uptake of cervical cytology was accounted for by Jarman score (t = -3.3), list inflation (-0.41), the proportion of practitioners over 65 (-0.64), the number of ancillary staff per practitioner (2.5), and 70% of the variation in immunisation rates by standardised mortality ratios (-6.6), the proportion of practitioners aged over 65 (-4.8), and the number of practice nurses per practitioner (3.5). Standardised mortality ratios (8.4), the number of practitioners (2.3), and the proportion over 65 (2.2), and the number of ancillary staff per practitioner (-3.1) accounted for 69% of variation in prescribing rates. 54% of the variation in night visiting was explained by standardised mortality ratios (7.1), the proportion of practitioners with lists sizes below 1000 (-2.2), the proportion aged over 65 (-0.4), and the number of practice nurses per practitioner (-2.5). CONCLUSIONS--Family health services authorities are appropriate systems for studying output of general practice. Their performance indicators need to be refined and to be linked to other relevant factors, notably the performance of hospital, community, and social services. PMID:1653065

Snacking now or later? Individual differences in following intentions or habits explained by time perspective.

PubMed

Onwezen, M C; Van 't Riet, J; Dagevos, H; Sijtsema, S J; Snoek, H M

2016-12-01

Even when individuals are aware of long-term health effects of their diet, and form healthy intentions, they often engage in relatively unhealthy snacking habits. Some individuals fall back on unhealthy habits more easily than others. We aim to explore whether time perspective can explain why some individuals are more prone to rely on habits and others on intentions. Study 1 (N = 1503) provides a first exploration of the role of time perspective by exploring individual differences in perception of long-term and short-term consequences. In accordance with our hypotheses, Study 1 shows that habits are associated with short-term consequences and intentions with long-term consequences. Study 2 (N = 1497) shows that the effects of habits on snacking behaviour are strengthened by a present time perspective, whereas the effects of intentions on snacking behaviour are strengthened by a future time perspective. These findings imply that there is a fundamental difference in the guiding function of intentions and habits which might explain individual differences in following intentions versus habits. Individuals with a long-term perspective are more inclined to follow intentions and individuals with a short-term perspective are more inclined to follow habits. Copyright © 2016 Elsevier Ltd. All rights reserved.

Moving in time: Bayesian causal inference explains movement coordination to auditory beats

PubMed Central

Elliott, Mark T.; Wing, Alan M.; Welchman, Andrew E.

2014-01-01

Many everyday skilled actions depend on moving in time with signals that are embedded in complex auditory streams (e.g. musical performance, dancing or simply holding a conversation). Such behaviour is apparently effortless; however, it is not known how humans combine auditory signals to support movement production and coordination. Here, we test how participants synchronize their movements when there are potentially conflicting auditory targets to guide their actions. Participants tapped their fingers in time with two simultaneously presented metronomes of equal tempo, but differing in phase and temporal regularity. Synchronization therefore depended on integrating the two timing cues into a single-event estimate or treating the cues as independent and thereby selecting one signal over the other. We show that a Bayesian inference process explains the situations in which participants choose to integrate or separate signals, and predicts motor timing errors. Simulations of this causal inference process demonstrate that this model provides a better description of the data than other plausible models. Our findings suggest that humans exploit a Bayesian inference process to control movement timing in situations where the origin of auditory signals needs to be resolved. PMID:24850915

Factors That May Explain Differences between Home and Clinic Meal Preparation Task Assessments in Frail Older Adults

ERIC Educational Resources Information Center

Provencher, Veronique; Demers, Louise; Gelinas, Isabelle

2012-01-01

Meal preparation assessments conducted in clinical environments (such as rehabilitation settings) might not reflect frail patients' performance at home. In addition, factors that may explain differences in performance between settings remain unknown. The aim of this study was to compare home and clinic performance on meal preparation tasks in…

Explaining Variation in Instructional Time: An Application of Quantile Regression

ERIC Educational Resources Information Center

Corey, Douglas Lyman; Phelps, Geoffrey; Ball, Deborah Loewenberg; Demonte, Jenny; Harrison, Delena

2012-01-01

This research is conducted in the context of a large-scale study of three nationally disseminated comprehensive school reform projects (CSRs) and examines how school- and classroom-level factors contribute to variation in instructional time in English language arts and mathematics. When using mean-based OLS regression techniques such as…

Explaining Gender Gaps in English Composition and College Algebra in College: The Mediating Role of Psychosocial Factors

ERIC Educational Resources Information Center

Ndum, Edwin; Allen, Jeff; Way, Jason; Casillas, Alex

2018-01-01

We examined the role of six psychosocial factors (PSFs) in explaining gender gaps in English Composition (n = 8,633) and College Algebra (n = 2,261) using data of first-year female (55%) and male students from 42 colleges. Using a multilevel model and controlling for prior achievement, we found that PSFs mediated between 3% and 41% of the gender…

How to explain Si isotopes of chert?

NASA Astrophysics Data System (ADS)

Liu, Y.

2016-12-01

The variations of d30Si values in diagenetic chert and chert- associated BIFs over time can be used to reconstruct the environmental conditions of the early Earth, and become a hot topic in the Si isotope society. However, there are several different views of explaining the variation of d30Si values over time. Moreover, there are disputes in explaining the distribution of Si isotope in several main reservoirs in surface systems. Those disagreements are caused by lacking key Si isotope fractionation factors associated with the formation processes of chert and its altered products. There are many unexplained observations about Si isotope distributions in Earth's surface systems (Opfergelt and Delmelle, 2012). For example, the deduced Si isotope equilibrium fractionation factors by Rayleigh model at ambient temperature between clay and the solution D30Siclay-solution = -1.5 ‰ and -2.05 ‰ (Hughes et al., 2013) obviously disagree with common sense, which dictates that stiffer chemical bonds will enrich heavier isotopes, i.e., the precipitated minerals will preferentially incorporate heavy isotopes relative to aqueous H4SiO4 due to their shorter Si-O bonds. Another similar case is the fractionation between quartz and solution. Most field observations suggested that solution will be enriched with heavier Si isotope compared to quartz, conflicting to the fact that quartz is the one with much shorter Si-O bonds than aqueous H4SiO4 (ca. 1.610Å vs. 1.639Å). Here we provide equilibrium and kinetic Si isotope fractionation factors associated with the formation of amorphous quartz and other secondary minerals in polymerization, co-precipitation and adsorption processes. The adsorption processes of silica gel to Fe-hydroxides have been carefully examined. The Si isotope fractionations due to the formation of mono-dentate to quadru-dentate adsorbed Fe-Si complexes have been calculated. These data can explain well the experimental observations (e.g., Zheng et al., 2016) and

Using social cognitive theory to explain discretionary, "leisure-time" physical exercise among high school students.

PubMed

Winters, Eric R; Petosa, Rick L; Charlton, Thomas E

2003-06-01

To examine whether knowledge of high school students' actions of self-regulation, and perceptions of self-efficacy to overcome exercise barriers, social situation, and outcome expectation will predict non-school related moderate and vigorous physical exercise. High school students enrolled in introductory Physical Education courses completed questionnaires that targeted selected Social Cognitive Theory variables. They also self-reported their typical "leisure-time" exercise participation using a standardized questionnaire. Bivariate correlation statistic and hierarchical regression were conducted on reports of moderate and vigorous exercise frequency. Each predictor variable was significantly associated with measures of moderate and vigorous exercise frequency. All predictor variables were significant in the final regression model used to explain vigorous exercise. After controlling for the effects of gender, the psychosocial variables explained 29% of variance in vigorous exercise frequency. Three of four predictor variables were significant in the final regression equation used to explain moderate exercise. The final regression equation accounted for 11% of variance in moderate exercise frequency. Professionals who attempt to increase the prevalence of physical exercise through educational methods should focus on the psychosocial variables utilized in this study.

Forecasting malaria cases using climatic factors in delhi, India: a time series analysis.

PubMed

Kumar, Varun; Mangal, Abha; Panesar, Sanjeet; Yadav, Geeta; Talwar, Richa; Raut, Deepak; Singh, Saudan

2014-01-01

Background. Malaria still remains a public health problem in developing countries and changing environmental and climatic factors pose the biggest challenge in fighting against the scourge of malaria. Therefore, the study was designed to forecast malaria cases using climatic factors as predictors in Delhi, India. Methods. The total number of monthly cases of malaria slide positives occurring from January 2006 to December 2013 was taken from the register maintained at the malaria clinic at Rural Health Training Centre (RHTC), Najafgarh, Delhi. Climatic data of monthly mean rainfall, relative humidity, and mean maximum temperature were taken from Regional Meteorological Centre, Delhi. Expert modeler of SPSS ver. 21 was used for analyzing the time series data. Results. Autoregressive integrated moving average, ARIMA (0,1,1) (0,1,0)(12), was the best fit model and it could explain 72.5% variability in the time series data. Rainfall (P value = 0.004) and relative humidity (P value = 0.001) were found to be significant predictors for malaria transmission in the study area. Seasonal adjusted factor (SAF) for malaria cases shows peak during the months of August and September. Conclusion. ARIMA models of time series analysis is a simple and reliable tool for producing reliable forecasts for malaria in Delhi, India.

Explaining use of food parenting practices: the importance of predisposing factors and parental cognitions.

PubMed

Gevers, Dorus Wm; van Assema, Patricia; de Vries, Nanne K; Kremers, Stef Pj

2017-09-01

The high energy intake from energy-dense foods among children in developed countries is undesirable. Improving food parenting practices has the potential to lower snack intakes among children. To inform the development of interventions, we aimed to predict food parenting practice patterns around snacking (i.e. 'high covert control and rewarding', 'low covert control and non-rewarding', 'high involvement and supportive' and 'low involvement and indulgent'). A cross-sectional survey was conducted. To predict the patterns of food parenting practices, multinomial logistic regression analyses were run with 888 parents. Predictors included predisposing factors (i.e. parents' and children's demographics and BMI, parents' personality, general parenting, and parenting practices used by their own parents) and parents' cognitions (i.e. perceived behaviour of other parents, subjective norms, attitudes, self-efficacy and outcome expectations). The Netherlands (October-November 2014). Dutch parents of children aged 4-12 years old. After backward elimination, nineteen factors had a statistically significant contribution to the model (Nagelkerke R 2=0·63). Overall, self-efficacy and outcome expectations were among the strongest explanatory factors. Considering the predisposing factors only, the general parenting factor nurturance most strongly predicted the food parenting clusters. Nurturance particularly distinguished highly involved parents from parents employing a pattern of low involvement. Parental cognitions and nurturance are important factors to explain the use of food parenting practices around snacking. The results suggest that intervention developers should attempt to increase self-efficacy and educate parents about what constitute effective and ineffective parenting practices. Promoting nurturance might be a prerequisite to achieve prolonged change.

Cognitive risk factors explain the relations between neuroticism and social anxiety for males and females.

PubMed

Allan, Nicholas P; Oglesby, Mary E; Uhl, Aubree; Schmidt, Norman B

2017-04-01

The hierarchical model of vulnerabilities to emotional distress contextualizes the relation between neuroticism and social anxiety as occurring indirectly through cognitive risk factors. In particular, inhibitory intolerance of uncertainty (IU; difficulty in uncertain circumstances), fear of negative evaluation (FNE; fear of being judged negatively), and anxiety sensitivity (AS) social concerns (fear of outwardly observable anxiety) are related to social anxiety. It is unclear whether these risk factors uniquely relate to social anxiety, and whether they account for the relations between neuroticism and social anxiety. The indirect relations between neuroticism and social anxiety through these and other risk factors were examined using structural equation modeling in a sample of 462 individuals (M age = 36.56, SD = 12.93; 64.3% female). Results indicated that the relations between neuroticism and social anxiety could be explained through inhibitory IU, FNE, and AS social concerns. No gender differences were found. These findings provide support for the hierarchical model of vulnerabilities to emotional distress disorders, although the cognitive risk factors accounted for variance beyond their contribution to the relation between neuroticism and social anxiety, suggesting a more complex model than that expressed in the hierarchical model of vulnerabilities.

Do factors related to combustion-based sources explain ...

EPA Pesticide Factsheets

Introduction: Spatial heterogeneity of effect estimates in associations between PM2.5 and total non-accidental mortality (TNA) in the United States (US), is an issue in epidemiology. This study uses rate ratios generated from the Multi-City/Multi-Pollutant study (1999-2005) for 313 core-based statistical areas (CBSA) and their metropolitan divisions (MD) to examine combustion-based sources of heterogeneity.Methods: For CBSA/MDs, area-specific log rate ratios (betas) were derived from a model adjusting for time, an interaction with age-group, day of week, and natural splines of current temperature, current dew point, and unconstrained temperature at lags 1, 2, and 3. We assessed the heterogeneity in the betas by linear regression with inverse variance weights, using average NO2, SO2, and CO, which may act as a combustion source proxy, and these pollutants’ correlations with PM2.5. Results: We found that weighted mean PM2.5 association (0.96 percent increase in total non-accidental mortality for a 10 µg/m3 increment in PM2.5) increased by 0.26 (95% confidence interval 0.08 , 0.44) for an interquartile change (0.2) in the correlation of SO2 and PM2.5., but betas showed less dependence on the annual averages of SO2 or NO2. Spline analyses suggest departures from linearity, particularly in a model that examined correlations between PM2.5 and CO.Conclusions: We conclude that correlations between SO2 and PM2.5 as an indicator of combustion sources explains some hete

How do passion for video games and needs frustration explain time spent gaming?

PubMed

Mills, Devin J; Milyavskaya, Marina; Mettler, Jessica; Heath, Nancy L; Derevensky, Jeffrey L

2018-04-01

Research applying self-determination theory and the dualistic model of passion (DMP) has shown video games may satisfy basic psychological needs (i.e., competence, autonomy, and relatedness) and be identified as a passion. The DMP distinguishes between healthy or harmonious passion and problematic or obsessive passion (OP), with the latter reflecting an overreliance towards one's passion to obtain needs satisfaction. The experience of daily obstructions to needs satisfaction, or needs frustration (NF), may facilitate such an overreliance. This study explored how NF and both types of passion explain the amount of time that university students spend gaming. The overall association between NF and time spent gaming was not significant. However, for video game users with low levels of OP for gaming, there was a significant negative association between NF and time spent gaming. Additionally, evidence of a mutually reinforcing association between NF and OP for gaming indicates that a vicious cycle exists, whereby a strong OP for gaming predicts and is reinforced by greater NF. The theoretical implications are discussed. © 2018 The British Psychological Society.

Ten-year changes in smoking among young adults: are racial differences explained by socioeconomic factors in the CARDIA study?

PubMed Central

Kiefe, C I; Williams, O D; Lewis, C E; Allison, J J; Sekar, P; Wagenknecht, L E

2001-01-01

OBJECTIVES: This study investigated whether socioeconomic factors explain racial/ethnic differences in regular smoking initiation and cessation. METHODS: Data were derived from the CARDIA study, a cohort of 5115 healthy adults aged 18 to 30 years at baseline (1985-1986) and recruited from the populations of 4 US cities. Respondents were followed over 10 years. RESULTS: Among 3950 respondents reexamined in 1995-1996, 20% of Whites and 33% of African Americans were smokers, as compared with 25% and 32%, respectively, in 1985-1986. On average, African Americans were of lower socioeconomic status. Ten-year regular smoking initiation rates for African American women, White women, African American men, and White men were 7.1%, 3.5%, 13.2%, and 5.1%, respectively, and the corresponding cessation rates were 25%, 35.1%, 19.2%, and 31.3%. After adjustment for socioeconomic factors, most 95% confidence intervals of the odds ratios for regular smoking initiation and cessation in African Americans vs Whites included 1. CONCLUSIONS: Less beneficial 10-year changes in smoking were observed in African Americans, but socioeconomic factors explained most of the racial disparity. PMID:11211629

Evaluating the importance of policy amenable factors in explaining influenza vaccination: a cross-sectional multinational study

PubMed Central

Wheelock, Ana; Miraldo, Marisa; Thomson, Angus; Vincent, Charles; Sevdalis, Nick

2017-01-01

Objectives Despite continuous efforts to improve influenza vaccination coverage, uptake among high-risk groups remains suboptimal. We aimed to identify policy amenable factors associated with vaccination and to measure their importance in order to assist in the monitoring of vaccination sentiment and the design of communication strategies and interventions to improve vaccination rates. Setting The USA, the UK and France. Participants A total of 2412 participants were surveyed across the three countries. Outcome measures Self-reported influenza vaccination. Methods Between March and April 2014, a stratified random sampling strategy was employed with the aim of obtaining nationally representative samples in the USA, the UK and France through online databases and random-digit dialling. Participants were asked about vaccination practices, perceptions and feelings. Multivariable logistic regression was used to identify factors associated with past influenza vaccination. Results The models were able to explain 64%–80% of the variance in vaccination behaviour. Overall, sociopsychological variables, which are inherently amenable to policy, were better at explaining past vaccination behaviour than demographic, socioeconomic and health variables. Explanatory variables included social influence (physician), influenza and vaccine risk perceptions and traumatic childhood experiences. Conclusions Our results indicate that evidence-based sociopsychological items should be considered for inclusion into national immunisation surveys to gauge the public’s views, identify emerging concerns and thus proactively and opportunely address potential barriers and harness vaccination drivers. PMID:28706088

Disentangling vegetation diversity from climate–energy and habitat heterogeneity for explaining animal geographic patterns

USGS Publications Warehouse

Jimenez-Alfaro, Borja; Chytry, Milan; Mucina, Ladislav; Grace, James B.; Rejmanek, Marcel

2016-01-01

Broad-scale animal diversity patterns have been traditionally explained by hypotheses focused on climate–energy and habitat heterogeneity, without considering the direct influence of vegetation structure and composition. However, integrating these factors when considering plant–animal correlates still poses a major challenge because plant communities are controlled by abiotic factors that may, at the same time, influence animal distributions. By testing whether the number and variation of plant community types in Europe explain country-level diversity in six animal groups, we propose a conceptual framework in which vegetation diversity represents a bridge between abiotic factors and animal diversity. We show that vegetation diversity explains variation in animal richness not accounted for by altitudinal range or potential evapotranspiration, being the best predictor for butterflies, beetles, and amphibians. Moreover, the dissimilarity of plant community types explains the highest proportion of variation in animal assemblages across the studied regions, an effect that outperforms the effect of climate and their shared contribution with pure spatial variation. Our results at the country level suggest that vegetation diversity, as estimated from broad-scale classifications of plant communities, may contribute to our understanding of animal richness and may be disentangled, at least to a degree, from climate–energy and abiotic habitat heterogeneity.

Explaining Algorithms: A New Perspective

ERIC Educational Resources Information Center

Müldner, Tomasz; Shakshuki, Elhadi

2006-01-01

This article presents a novel approach for explaining algorithms that aims to overcome various pedagogical limitations of the current visualization systems. The main idea is that at any given time, a learner is able to focus on a single problem. This problem can be explained, studied, understood, and tested, before the learner moves on to study…

Microhabitat and Climatic Niche Change Explain Patterns of Diversification among Frog Families.

PubMed

Moen, Daniel S; Wiens, John J

2017-07-01

A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal). The first two factors have been tested separately in several studies, but the relative importance of all three is largely unknown. Here we explore the correlates of diversification among families of frogs, which collectively represent ∼88% of amphibian species. We assemble and analyze data on phylogeny, climate, and microhabitat for thousands of species. We find that the best-fitting phylogenetic multiple regression model includes all three types of variables: microhabitat, rates of climatic niche change, and climatic niche position. This model explains 67% of the variation in diversification rates among frog families, with arboreal microhabitat explaining ∼31%, niche rates ∼25%, and climatic niche position ∼11%. Surprisingly, we show that microhabitat can have a much stronger influence on diversification than climatic niche position or rates of climatic niche change.

High Spending on Maternity Care in India: What Are the Factors Explaining It?

PubMed Central

Moradhvaj; Rammohan, Anu; Shruti; Pradhan, Jalandhar

2016-01-01

Background and Objectives High maternity-related health care spending is often cited as an important barrier in utilizing quality health care during pregnancy and childbirth. This study has two objectives: (i) to measure the levels of expenditure on total maternity care in disaggregated components such as ANCs, PNCs, and Natal care expenditure; (ii) to quantify the extent of catastrophic maternity expenditure (CME) incurred by households and identify the factors responsible for it. Methods and Findings Data from the 71st round of the National Sample Survey (2014) was used to estimate maternity expenditure and its predictors. CME was measured as a share of consumption expenditure by different cut-offs. The two-part model was used to identify the factors associated with maternity spending and CME. The findings show that household spending on maternity care (US$ 149 in constant price) is much higher than previous estimates (US$ 50 in constant price). A significant proportion of households in India (51%) are incurring CME. Along with economic and educational status, type of health care and place of residence emerged as significant factors in explaining CME. Conclusion Findings from this study assume importance in the context of an emerging demand for higher maternity entitlements and government spending on public health care in India. To reduce CME, India needs to improve the availability and accessibility of better-quality public health services and increase maternity entitlements in line with maternity expenditure identified in this study. PMID:27341520

High Spending on Maternity Care in India: What Are the Factors Explaining It?

PubMed

Goli, Srinivas; Moradhvaj; Rammohan, Anu; Shruti; Pradhan, Jalandhar

2016-01-01

High maternity-related health care spending is often cited as an important barrier in utilizing quality health care during pregnancy and childbirth. This study has two objectives: (i) to measure the levels of expenditure on total maternity care in disaggregated components such as ANCs, PNCs, and Natal care expenditure; (ii) to quantify the extent of catastrophic maternity expenditure (CME) incurred by households and identify the factors responsible for it. Data from the 71st round of the National Sample Survey (2014) was used to estimate maternity expenditure and its predictors. CME was measured as a share of consumption expenditure by different cut-offs. The two-part model was used to identify the factors associated with maternity spending and CME. The findings show that household spending on maternity care (US$ 149 in constant price) is much higher than previous estimates (US$ 50 in constant price). A significant proportion of households in India (51%) are incurring CME. Along with economic and educational status, type of health care and place of residence emerged as significant factors in explaining CME. Findings from this study assume importance in the context of an emerging demand for higher maternity entitlements and government spending on public health care in India. To reduce CME, India needs to improve the availability and accessibility of better-quality public health services and increase maternity entitlements in line with maternity expenditure identified in this study.

Explaining mortality rate plateaus

PubMed Central

Weitz, Joshua S.; Fraser, Hunter B.

2001-01-01

We propose a stochastic model of aging to explain deviations from exponential growth in mortality rates commonly observed in empirical studies. Mortality rate plateaus are explained as a generic consequence of considering death in terms of first passage times for processes undergoing a random walk with drift. Simulations of populations with age-dependent distributions of viabilities agree with a wide array of experimental results. The influence of cohort size is well accounted for by the stochastic nature of the model. PMID:11752476

Evaluating the importance of policy amenable factors in explaining influenza vaccination: a cross-sectional multinational study.

PubMed

Wheelock, Ana; Miraldo, Marisa; Thomson, Angus; Vincent, Charles; Sevdalis, Nick

2017-07-12

Despite continuous efforts to improve influenza vaccination coverage, uptake among high-risk groups remains suboptimal. We aimed to identify policy amenable factors associated with vaccination and to measure their importance in order to assist in the monitoring of vaccination sentiment and the design of communication strategies and interventions to improve vaccination rates. The USA, the UK and France. A total of 2412 participants were surveyed across the three countries. Self-reported influenza vaccination. Between March and April 2014, a stratified random sampling strategy was employed with the aim of obtaining nationally representative samples in the USA, the UK and France through online databases and random-digit dialling. Participants were asked about vaccination practices, perceptions and feelings. Multivariable logistic regression was used to identify factors associated with past influenza vaccination. The models were able to explain 64%-80% of the variance in vaccination behaviour. Overall, sociopsychological variables, which are inherently amenable to policy, were better at explaining past vaccination behaviour than demographic, socioeconomic and health variables. Explanatory variables included social influence (physician), influenza and vaccine risk perceptions and traumatic childhood experiences. Our results indicate that evidence-based sociopsychological items should be considered for inclusion into national immunisation surveys to gauge the public's views, identify emerging concerns and thus proactively and opportunely address potential barriers and harness vaccination drivers. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Coping Skills Help Explain How Future-Oriented Adolescents Accrue Greater Well-Being Over Time.

PubMed

Chua, Li Wen; Milfont, Taciano L; Jose, Paul E

2015-11-01

Adolescents who endorse greater levels of future orientation report greater well-being over time, but we do not know the mechanism by which this happens. The present longitudinal study examined whether both adaptive as well as maladaptive coping strategies might explain how future orientation leads to ill-being and well-being over time in young New Zealanders. A sample of 1,774 preadolescents and early adolescents (51.9 % female) aged 10-15 years at Time 1 completed a self-report survey three times with 1 year intervals in between. Longitudinal mediation path models were constructed to determine whether and how maladaptive and adaptive coping strategies at Time 2 functioned as mediators between future orientation at Time 1 and ill-being and well-being at Time 3. Results showed that future orientation predicted lower maladaptive coping, which in turn predicted lower substance use and self-harming behavior. All three well-being outcomes (i.e., happiness with weight, vitality, and sleep) were consistently predicted by future orientation, and all three pathways were mediated by both lower maladaptive and higher adaptive coping strategies (with the exception of happiness with weight, which was mediated only by lower maladaptive coping). The results suggest that several pathways by which future orientation leads to greater well-being occurs through an increased use of adaptive coping, a decreased use of maladaptive coping, or both.

An Underlying Common Factor, Influenced by Genetics and Unique Environment, Explains the Covariation Between Major Depressive Disorder, Generalized Anxiety Disorder, and Burnout: A Swedish Twin Study.

PubMed

Mather, Lisa; Blom, Victoria; Bergström, Gunnar; Svedberg, Pia

2016-12-01

Depression and anxiety are highly comorbid due to shared genetic risk factors, but less is known about whether burnout shares these risk factors. We aimed to examine whether the covariation between major depressive disorder (MDD), generalized anxiety disorder (GAD), and burnout is explained by common genetic and/or environmental factors. This cross-sectional study included 25,378 Swedish twins responding to a survey in 2005-2006. Structural equation models were used to analyze whether the trait variances and covariances were due to additive genetics, non-additive genetics, shared environment, and unique environment. Univariate analyses tested sex limitation models and multivariate analysis tested Cholesky, independent pathway, and common pathway models. The phenotypic correlations were 0.71 (0.69-0.74) between MDD and GAD, 0.58 (0.56-0.60) between MDD and burnout, and 0.53 (0.50-0.56) between GAD and burnout. Heritabilities were 45% for MDD, 49% for GAD, and 38% for burnout; no statistically significant sex differences were found. A common pathway model was chosen as the final model. The common factor was influenced by genetics (58%) and unique environment (42%), and explained 77% of the variation in MDD, 69% in GAD, and 44% in burnout. GAD and burnout had additive genetic factors unique to the phenotypes (11% each), while MDD did not. Unique environment explained 23% of the variability in MDD, 20% in GAD, and 45% in burnout. In conclusion, the covariation was explained by an underlying common factor, largely influenced by genetics. Burnout was to a large degree influenced by unique environmental factors not shared with MDD and GAD.

Temporal changes of spatial soil moisture patterns: controlling factors explained with a multidisciplinary approach

NASA Astrophysics Data System (ADS)

Martini, Edoardo; Wollschläger, Ute; Kögler, Simon; Behrens, Thorsten; Dietrich, Peter; Reinstorf, Frido; Schmidt, Karsten; Weiler, Markus; Werban, Ulrike; Zacharias, Steffen

2016-04-01

different hydrologic conditions and the factors controlling the temporal variability of the ECa-soil moisture relationship. The approach provided valuable insight into the time-varying contribution of local and nonlocal factors to the characteristic spatial patterns of soil moisture and the transition mechanisms. The spatial organization of soil moisture was controlled by different processes in different soil horizons, and the topsoil's moisture did not mirror processes that take place within the soil profile. Results show that, for the Schäfertal hillslope site which is presumed to be representative for non-intensively managed soils with moderate clay content, local soil properties (e.g., soil texture and porosity) are the major control on the spatial pattern of ECa. In contrast, the ECa-soil moisture relationship is small and varies over time indicating that ECa is not a good proxy for soil moisture estimation at the investigated site.Occasionally observed stronger correlations between ECa and soil moisture may be explained by background dependencies of ECa to other state variables such as pore water electrical conductivity. The results will help to improve conceptual understanding for hydrological model studies at similar or smaller scales, and to transfer observation concepts and process understanding to larger or less instrumented sites, as well as to constrain the use of EMI-based ECa data for hydrological applications.

Home on the Range: Factors Explaining Partial Migration of African Buffalo in a Tropical Environment

PubMed Central

Naidoo, Robin; Du Preez, Pierre; Stuart-Hill, Greg; Jago, Mark; Wegmann, Martin

2012-01-01

Partial migration (when only some individuals in a population undertake seasonal migrations) is common in many species and geographical contexts. Despite the development of modern statistical methods for analyzing partial migration, there have been no studies on what influences partial migration in tropical environments. We present research on factors affecting partial migration in African buffalo (Syncerus caffer) in northeastern Namibia. Our dataset is derived from 32 satellite tracking collars, spans 4 years and contains over 35,000 locations. We used remotely sensed data to quantify various factors that buffalo experience in the dry season when making decisions on whether and how far to migrate, including potential man-made and natural barriers, as well as spatial and temporal heterogeneity in environmental conditions. Using an information-theoretic, non-linear regression approach, our analyses showed that buffalo in this area can be divided into 4 migratory classes: migrants, non-migrants, dispersers, and a new class that we call “expanders”. Multimodel inference from least-squares regressions of wet season movements showed that environmental conditions (rainfall, fires, woodland cover, vegetation biomass), distance to the nearest barrier (river, fence, cultivated area) and social factors (age, size of herd at capture) were all important in explaining variation in migratory behaviour. The relative contributions of these variables to partial migration have not previously been assessed for ungulates in the tropics. Understanding the factors driving migratory decisions of wildlife will lead to better-informed conservation and land-use decisions in this area. PMID:22570722

Impact of patient and environmental factors on capillary refill time in adults.

PubMed

Anderson, Bronwyn; Kelly, Anne-Maree; Kerr, Debra; Clooney, Megan; Jolley, Damien

2008-01-01

Capillary refill time (CRT) has been taught as a rapid indicator of circulatory status. The aim of this study was to define normal CRT in the Australian context and the environmental, patient, and drug factors that influence it. This prospective observational study included healthy adults at hospital clinics, workplaces, universities, and community groups. Volunteer participants provided their age, sex, ethnic group, and use of hypertensive or cardiac medications. Capillary refill time, ambient temperature, and patient temperature were recorded in a standard manner. Data were analyzed using descriptive statistics and regression analyses. The 95th percentile was used to define the upper limit of normal. One thousand participants were included; 57% were women, 90% were white, and 21% were taking cardiac medications. The median CRT was 1.9 seconds (95th percentile, 3.5 seconds). The CRT increased 3.3% for each additional decade of age. The CRT was also on average 7% lower in men than in women. The CRT decreased by 1.2% per degree-Celsius rise of ambient temperature, independently of patient's temperature, and decreased by 5% for each degree-Celsius rise in patient temperature, independently of ambient temperature. On multivariant analysis, age, sex, ambient temperature, and patient temperature were statistically significant predictors of CRT, but together explain only 8% of the observed variability. Capillary refill time varies with environmental and patient factors, but these account for only a small proportion of the variability observed. Its suitability as a reliable clinical test is doubtful.

Neuroticism Combined With Slower and More Variable Reaction Time: Synergistic Risk Factors for 7-Year Cognitive Decline in Females

PubMed Central

Shickle, Darren A.; Roberts, Beverly A.; Deary, Ian J.

2012-01-01

Objective. Among adults, slower and more variable reaction times are associated with worse cognitive function and increased mortality risk. Therefore, it is important to elucidate risk factors for reaction time change over the life course. Method. Data from the Health and Lifestyle Survey (HALS) were used to examine predictors of 7-year decline in reaction time (N = 4,260). Regression-derived factor scores were used to summarize general change across 4 reaction time variables: simple mean, 4-choice mean, simple variability, and 4-choice variability (53.52% of variance). Results. Age (B = .02, p < .001) and HALS1 baseline reaction time (B = −.10, p = .001) were significant risk factors for males (N = 1,899). In addition to these variables, in females (N = 2,361), neuroticism was significant and interacted synergistically with baseline reaction time (B = .06, p = .04). Adjustment for physiological variables explained the interaction with neuroticism, suggesting that candidate mechanisms had been identified. Discussion. A priority for future research is to replicate interactions between personality and reaction time in other samples and find specific mechanisms. Stratification of population data on cognitive health by personality and reaction time could improve strategies for identifying those at greater risk of cognitive decline. PMID:22367712

What Factors Explain Harmful Algal Blooms of Dinophysis Along the Texas Coast?

NASA Astrophysics Data System (ADS)

Replogle, L.; Henrichs, D.; Campbell, L.

2016-02-01

The toxic dinoflagellate Dinophysis ovum is one of the harmful algal species that bloom along the Texas coast. Blooms of D. ovum can be explained by several factors that work together to cause bloom initiation. This work utilized image counts collected by the Imaging FlowCytobot (IFCB) at Port Aransas, TX and modeled winds from the European Centre for Medium-range Weather Forecasts. Based on a previous study of another dinoflagellate species, it was hypothesized that winds will be highly correlated with harmful algal bloom (HAB) years versus non-HAB years for D. ovum. Weak northerly winds and downwelling along the coast will be associated with HAB years, while strong northerly or southerly winds will be associated with non-HAB years. In non-HAB years, wind-driven currents caused by upcoast or strongly flowing downcoast winds will result in northward or southward movement of D. ovum cells. In HAB years, weaker downcoast winds will allow for accumulation of D. ovum at the coast. Results showed that weak downcoast, along-shore winds occurred in the weeks preceding HAB events in 2008, 2010, 2011, 2012 and 2014, and likely contributed to the accumulation of Dinophysis cells along the Texas coast. When winds moved upcoast or strongly downcoast in the weeks preceding bloom months, Dinophysis blooms did not occur. Additional factors (e.g. sea surface temperature, surface-based runoff, El Niño Southern Oscillation, North Atlantic Oscillation and salinity) were analyzed to better define a favorable environment for bloom formation. Sea surface temperature and surface based runoff were significantly correlated with bloom occurrence, whereas El Niño Southern Oscillation and the North Atlantic Oscillation were not.

The Contribution of Home, Neighbourhood and School Environmental Factors in Explaining Physical Activity among Adolescents

PubMed Central

Haerens, Leen; Craeynest, Mietje; Deforche, Benedicte; Maes, Lea; Cardon, Greet; De Bourdeaudhuij, Ilse

2009-01-01

The present study aimed at investigating the influence of home, neighbourhood and school environmental factors on adolescents' engagement in self-reported extracurricular physical activity and leisure time sports and on MVPA objectively measured by accelerometers. Environmental factors were assessed using questionnaires. Gender specific hierarchical regression analyses were conducted, with demographic variables entered in the first block, and environmental, psychosocial factors and interactions terms entered in the second block. Participation in extracurricular activities at school was positively related to the number of organized activities and the provision of supervision. Perceived accessibility of neighborhood facilities was not related to engagement in leisure time sports, whereas the availability of sedentary and physical activity equipment was. Findings were generally supportive of ecological theories stating that behaviors are influenced by personal and environmental factors that are constantly interacting. PMID:20041023

Explaining why larks are future-oriented and owls are present-oriented: self-control mediates the chronotype-time perspective relationships.

PubMed

Milfont, Taciano L; Schwarzenthal, Miriam

2014-05-01

Recent studies provide evidence for the chronotype-time perspective relationships. Larks are more future-oriented and owls are more present-oriented. The present study expands this initial research by examining whether the associations are replicable with other time perspective measures, and whether self-control explains the observed relationships. Chronotype was assessed with the Morningness-Eveningness Questionnaire and the basic associations with the Zimbardo Time Perspective Inventory were replicated in a sample of 142 New Zealand students, but not with other measures. Self-control mediated the influence of morningness on both future time perspective and delay of gratification. Implications of the findings are discussed.

Explaining socio-demographic differences in disengagement from sports in adolescence.

PubMed

Prins, Richard G; Kamphuis, Carlijn B M; van Empelen, Pepijn; Beenackers, Mariëlle A; Brug, Johannes; Mackenbach, Johan P; Oenema, Anke

2013-10-01

The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. Data were obtained from the Environmental Determinants of Obesity in Rotterdam Schoolchildren study, and 357 adolescents were eligible for analysis. Socio-demographics (gender, ethnicity, education), individual cognitions and neighbourhood perceptions were assessed at baseline (2005/2006), and sports participation at baseline and at follow-up (2007/2008). Two dichotomous outcome variables were constructed: (i) disengagement from sports (yes/no) and (ii) ceased compliance with the fitnorm (i.e. cease engaging in sports ≥3 times/wk) (yes/no). In logistic regression and mediation analyses, we identified socio-demographic differences in the two outcomes. Subsequently, we applied mediation analyses to identify the contribution of cognitive and environmental explanatory factors of the socio-demographic differences. Girls [odds ratio (OR): 2.5, 95% confidence interval (CI): 1.5-4.5] were more likely than boys to disengage from sports. Girls (OR: 2.5, 95% CI: 1.4-4.2), adolescents of non-Western background (OR: 1.8, 95% CI: 1.0-3.0) and those in lower educational levels (OR: 1.7, 95% CI: 1.0-2.9) were more likely to cease compliance with the fitnorm. Perceived neighbourhood safety partly explained gender differences in disengagement from sports (8%). Intention partly explained ethnical (32%) and educational differences (37%) in ceasing compliance with the fitnorm. Girls, lower-educated adolescents and those with a non-Western background showed more pronounced reductions in sports participation and compliance with the fitnorm. Intention and perceived neighbourhood safety could partially explain these differences.

System factors to explain H1N1 state vaccination rates for adults in US emergency response to pandemic.

PubMed

Davila-Payan, Carlo; Swann, Julie; Wortley, Pascale M

2014-05-23

During the 2009-2010 H1N1 pandemic, vaccine in short supply was allocated to states pro rata by population, yet the vaccination rates of adults differed by state. States also differed in their campaign processes and decisions. Analyzing the campaign provides an opportunity to identify specific approaches that may result in higher vaccine uptake in a future event of this nature. To determine supply chain and system factors associated with higher state H1N1 vaccination coverage for adults in a system where vaccine was in short supply. Regression analysis of factors predicting state-specific H1N1 vaccination coverage in adults. Independent variables included state campaign information, demographics, preventive or health-seeking behavior, preparedness funding, providers, state characteristics, and H1N1-specific state data. The best model explained the variation in state-specific adult vaccination coverage with an adjusted R-squared of 0.76. We found that higher H1N1 coverage of adults is associated with program aspects including shorter lead-times (i.e., the number of days between when doses were allocated to a state and were shipped, including the time for states to order the doses) and less vaccine directed to specialist locations. Higher vaccination coverage is also positively associated with the maximum number of ship-to locations, past seasonal influenza vaccination coverage, the percentage of women with a Pap smear, the percentage of the population that is Hispanic, and negatively associated with a long duration of the epidemic peak. Long lead-times may be a function of system structure or of efficiency and may suggest monitoring or redesign of distribution processes. Sending vaccine to sites with broad access could be useful when covering a general population. Existing infrastructure may be reflected in the maximum number of ship-to locations, so strengthening routine influenza vaccination programs may help during emergency vaccinations also. Future research

Endogenous timing factors in bird migration

NASA Technical Reports Server (NTRS)

Gwinner, E. G.

1972-01-01

Several species of warbler birds were observed in an effort to determine what initiates and terminates migration. Environmental and endogenous timing mechanisms were analyzed. The results indicate that endogenous stimuli are dominant factors for bird migration especially for long distances. It was concluded that environmental factors act as an assist mechanism.

Job demand and control in mid-life and physical and mental functioning in early old age: do childhood factors explain these associations in a British birth cohort?

PubMed Central

von Bonsdorff, Mikaela B; Cooper, Rachel; Kuh, Diana

2014-01-01

Objectives Adverse work-related exposures have been linked with decreased physical and mental functioning in later life, however, whether childhood factors explain the associations between work exposures and functioning is unknown. Our aim was to investigate if job demand and control in mid-life were related to self-reported physical and mental functioning in early old age and whether childhood factors explained these associations. Design Prospective cohort study. Setting England, Scotland and Wales. Participants and outcome measures Data come from the UK Medical Research Council National Survey of Health and Development, a cohort with follow-up since birth in 1946. 1485 occupationally active study members had data available on job demand and control in mid-life and on physical and mental functioning assessed using the Short Form-36 questionnaire at 60–64 years. Results Those with higher job control in mid-life had better physical functioning than those who reported lower job control (β 0.51, 95% CI 0.02 to 1.01, p=0.04 adjusted for adult confounders). Those with higher job demand in mid-life had poorer mental functioning (β −0.82, 95% CI −1.14 to −0.51, p<0.001). Associations between job control and mental functioning were similar but less pronounced. Adjustment for childhood factors (father's and mother's educational attainment, parents’ interest in school at age 7 and cognitive ability at age 8) partially explained the association between job control and physical functioning, but did not explain the association between job demand and mental functioning. Conclusions Job demand and control in mid-life are differentially associated with mental and physical functioning in early old age and some of these associations may be partially explained by childhood factors. PMID:25319998

Factors affecting medication-order processing time.

PubMed

Beaman, M A; Kotzan, J A

1982-11-01

The factors affecting medication-order processing time at one hospital were studied. The order processing time was determined by directly observing the time to process randomly selected new drug orders on all three work shifts during two one-week periods. An order could list more than one drug for an individual patient. The observer recorded the nature, location, and cost of the drugs ordered, as well as the time to process the order. The time and type of interruptions also were noted. The time to process a drug order was classified as six dependent variables: (1) total time, (2) work time, (3) check time, (4) waiting time I--time from arrival on the dumbwaiter until work was initiated, (5) waiting time II--time between completion of the work and initiation of checking, and (6) waiting time III--time after the check was completed until the order left on the dumbwaiter. The significant predictors of each of the six dependent variables were determined using stepwise multiple regression. The total time to process a prescription order was 58.33 +/- 48.72 minutes; the urgency status of the order was the only significant determinant of total time. Urgency status also significantly predicted the three waiting-time variables. Interruptions and the number of drugs on the order were significant determinants of work time and check time. Each telephone interruption increased the work time by 1.72 minutes. While the results of this study cannot be generalized to other institutions, pharmacy managers can use the method of determining factors that affect medication-order processing time to identify problem areas in their institutions.

Do executive functions explain the covariance between internalizing and externalizing behaviors?

PubMed

Hatoum, Alexander S; Rhee, Soo Hyun; Corley, Robin P; Hewitt, John K; Friedman, Naomi P

2017-11-16

This study examined whether executive functions (EFs) might be common features of internalizing and externalizing behavior problems across development. We examined relations between three EF latent variables (a common EF factor and factors specific to updating working memory and shifting sets), constructed from nine laboratory tasks administered at age 17, to latent growth intercept (capturing stability) and slope (capturing change) factors of teacher- and parent-reported internalizing and externalizing behaviors in 885 individual twins aged 7 to 16 years. We then estimated the proportion of intercept-intercept and slope-slope correlations predicted by EF as well as the association between EFs and a common psychopathology factor (P factor) estimated from all 9 years of internalizing and externalizing measures. Common EF was negatively associated with the intercepts of teacher-rated internalizing and externalizing behavior in males, and explained 32% of their covariance; in the P factor model, common EF was associated with the P factor in males. Shifting-specific was positively associated with the externalizing slope across sex. EFs did not explain covariation between parent-rated behaviors. These results suggest that EFs are associated with stable problem behavior variation, explain small proportions of covariance, and are a risk factor that that may depend on gender.

Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam.

PubMed

Thai, Pham Quang; Choisy, Marc; Duong, Tran Nhu; Thiem, Vu Dinh; Yen, Nguyen Thu; Hien, Nguyen Tran; Weiss, Daniel J; Boni, Maciej F; Horby, Peter

2015-12-01

Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the seasonality of ILI. We used 18 years (1993-2010) of monthly ILI notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. Seasonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project. The intensity of ILI seasonality in Vietnam is best explained by the intensity of AH seasonality. We find that ILI seasonality is weak in provinces experiencing weak seasonal fluctuations in AH (annual power <17.6), whereas ILI seasonality is strongest in provinces with pronounced AH seasonality (power >17.6). In Vietnam, AH and ILI are positively correlated. Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of

Pain rather than self-reported sedentary time explains variation in perceived health and activity limitation in persons with rheumatoid arthritis: a cross sectional study in Sweden.

PubMed

Demmelmaier, Ingrid; Åsenlöf, Pernilla; Bergman, Patrick; Nordgren, Birgitta; Opava, Christina H

2017-06-01

To investigate (1) the amount of self-reported time spent sedentary among a large cohort of persons with rheumatoid arthritis (RA), and (2) the contribution of sedentary time to explain perceived health and activity limitation in RA beyond that of previously known correlates. This cross-sectional study used data from a postal questionnaire and the Swedish Rheumatology Quality registers (SRQ). The International Physical Activity Questionnaire was used to assess sedentary time (sitting) and moderate, vigorous and walking activity (MVPA). Sociodemographics, pain, fatigue, fear-avoidance beliefs, anxiety/depression, disease duration, MVPA and sedentary time were included in multiple regression models with perceived health (Visual Analogue Scale 0-100) and activity limitation (Stanford Health Assessment Questionnaire) as dependent variables. In all 3152 (59%) of 5391 persons identified as eligible from the SRQ, responded to the questionnaire. 2819 individuals with complete data on all study variables were analysed. Mean time (SD) spent sedentary was 257 (213) minutes per day. Sedentary time did not contribute significantly to explain perceived health and only minimally to explain activity limitation. Instead, variation was mainly explained by pain; for perceived health (Beta = 0.780, p < 0.001) and for activity limitation (Beta = 0.445, p < 0.001).The results indicate a non-significant role of sedentary time and a need for increased focus on pain in the management of RA. Future studies should use prospective designs and objective assessment methods to further investigate the associations between sedentary time and health outcomes in persons with RA.

Time-fixed rendezvous by impulse factoring with an intermediate timing constraint. [for transfer orbits

NASA Technical Reports Server (NTRS)

Green, R. N.; Kibler, J. F.; Young, G. R.

1974-01-01

A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods.

Factors behind Leisure-Time Physical Activity Behavior Based on Finnish Twin Studies: The Role of Genetic and Environmental Influences and the Role of Motives

PubMed Central

Kujala, Urho M.; Kaprio, Jaakko

2014-01-01

Different approaches are being taken to clarify the role of various factors in the development of physical activity behaviors. Genetic studies are a new area of physical activity research and also the motives for physical activity have been widely studied. The purpose of this paper is to review the findings emerging from the longitudinal genetic studies on leisure-time physical activity and to evaluate the associations between motivational factors and leisure-time physical activity. The focus is to review recent findings of longitudinal Finnish twin studies. The results of the latest longitudinal Finnish twin studies point to the existence of age-specific genetic and environmental influences on leisure-time physical activity. Variations in environmental factors seem to explain the observed deterioration in leisure-time physical activity levels. A decline in genetic influences is seen first from adolescence to young adulthood and again from the age of thirty to the mid-thirties. In the Finnish twin participants, mastery, physical fitness, and psychological state were the major motivation factors associated with consistent leisure-time physical activity behavior. The results also indicate that intrinsic motivation factors may be important for engagement in leisure-time physical activity. PMID:24809061

Factors behind leisure-time physical activity behavior based on Finnish twin studies: the role of genetic and environmental influences and the role of motives.

PubMed

Aaltonen, Sari; Kujala, Urho M; Kaprio, Jaakko

2014-01-01

Different approaches are being taken to clarify the role of various factors in the development of physical activity behaviors. Genetic studies are a new area of physical activity research and also the motives for physical activity have been widely studied. The purpose of this paper is to review the findings emerging from the longitudinal genetic studies on leisure-time physical activity and to evaluate the associations between motivational factors and leisure-time physical activity. The focus is to review recent findings of longitudinal Finnish twin studies. The results of the latest longitudinal Finnish twin studies point to the existence of age-specific genetic and environmental influences on leisure-time physical activity. Variations in environmental factors seem to explain the observed deterioration in leisure-time physical activity levels. A decline in genetic influences is seen first from adolescence to young adulthood and again from the age of thirty to the mid-thirties. In the Finnish twin participants, mastery, physical fitness, and psychological state were the major motivation factors associated with consistent leisure-time physical activity behavior. The results also indicate that intrinsic motivation factors may be important for engagement in leisure-time physical activity.

Individual and hospital-specific factors influencing medical graduates' time to medical specialization.

PubMed

Johannessen, Karl-Arne; Hagen, Terje P

2013-11-01

Previous studies of gender differences in relation to medical specialization have focused more on social variables than hospital-specific factors. In a multivariate analysis with extended Cox regression, we used register data for socio-demographic variables (gender, family and having a child born during the study period) together with hospital-specific variables (the amount of supervision available, efficiency pressure and the type of teaching hospital) to study the concurrent effect of these variables on specialty qualification among all 2474 Norwegian residents who began specialization in 1999-2001. We followed the residents until 2010. A lower proportion of women qualified for a specialty in the study period (67.9% compared with 78.7% of men, p < 0.001), and they took on average six months longer than men did to complete the specialization qualification (p < 0.01). Fewer women than men entered specialties providing emergency services and those with longer working hours, and women worked shorter hours than men in all specialties. Hospital factors were significant predictors for the timely attainment of specialization: working at university hospitals (regional) or central hospitals was associated with a reduction in the time taken to complete the specialization, whereas an increased patient load and less supervision had the opposite effect. Multivariate analysis showed that the smaller proportion of women who qualified for a specialty was explained principally by childbirth and by the number of children aged under 18 years. Copyright © 2013 Elsevier Ltd. All rights reserved.

Factors That Explains Student Anxiety toward Mathematics

ERIC Educational Resources Information Center

García-Santillán, Arturo; Escalera-Chávez, Milka Elena; Moreno-García, Elena; Santana-Villegas, Josefina del Carmen

2016-01-01

The aim of this research is to test whether anxiety toward mathematics is made up of a five-factor structure: anxiety toward evaluation, anxiety toward temporality, anxiety toward understanding of mathematical problems, anxiety toward numbers and operations, and anxiety toward mathematical situations in real life. Our study sample was formed of…

Factors related to consultation time: Experience in Slovenia

PubMed Central

Petek Šter, Marija; Švab, Igor; Živčec Kalan, Gordana

2008-01-01

Objective Consultation time has a serious impact on physicians’ work and patient satisfaction. No systematic study of consultation time in general practice in Slovenia has yet been carried out. The aim of the present study was to measure consultation time, to identify the factors influencing it, and to study the influence of the workload of general practitioners on consultation time. Design A total of 42 general practitioners participated in this cross-sectional study. Each physician collected data from 300 consecutive consultations and measured the length of the visit. Setting Forty-two randomly selected general practices in Slovenia. Subjects Patients of 42 general practices. Main outcome measures Average consultation time in general practice in Slovenia; factors influencing consultation time in Slovenia. Results Data from 12 501 visits to the surgery were collected. A quarter of all visits (25.5%) were administrative. The mean consultation time was 6.9 minutes (median 6.0 minutes, 5%–95% interval: 1.0–16.0 minutes). Longer consultation time was predicted by: patient-related factors (female gender, higher age, higher level of education, higher number of health problems, change of physician within the last year), physician-related factors (higher age), physicians’ workload (absence of high workload), and the type of visit (consultation and/or clinical examination). Conclusion Consultation time in general practice is short, and depends on the characteristics of the patient and the physician, the physician's workload, and the type of visit. A reduction of high workload in general practice should be one of the priorities of the healthcare system. PMID:18297560

A Survey of Factors Influencing High School Start Times

ERIC Educational Resources Information Center

Wolfson, Amy R.; Carskadon, Mary A.

2005-01-01

The present study surveyed high school personnel regarding high school start times, factors influencing school start times, and decision making around school schedules. Surveys were analyzed from 345 secondary schools selected at random from the National Center for Educational Statistics database. Factors affecting reported start times included…

Factors Explaining Racial/Ethnic Disparities in Rates of Physician Recommendation for Colorectal Cancer Screening

PubMed Central

Pelletier, Valerie; Winter, Kelly; Albatineh, Ahmed N.

2013-01-01

Objectives. Physician recommendation plays a crucial role in receiving endoscopic screening for colorectal cancer (CRC). This study explored factors associated with racial/ethnic differences in rates of screening recommendation. Methods. Data on 5900 adults eligible for endoscopic screening were obtained from the National Health Interview Survey. Odds ratios of receiving an endoscopy recommendation were calculated for selected variables. Planned, sequenced logistic regressions were conducted to examine the extent to which socioeconomic and health care variables account for racial/ethnic disparities in recommendation rates. Results. Differential rates were observed for CRC screening and screening recommendations among racial/ethnic groups. Compared with Whites, Hispanics were 34% less likely (P < .01) and Blacks were 26% less likely (P < .05) to receive this recommendation. The main predictors that emerged in sequenced analysis were education for Hispanics and Blacks and income for Blacks. After accounting for the effects of usual source of care, insurance coverage, and education, the disparity reduced and became statistically insignificant. Conclusions. Socioeconomic status and access to health care may explain major racial/ethnic disparities in CRC screening recommendation rates. PMID:23678899

Social disorganization and the profile of child welfare: Explaining child welfare activity by the community-level factors.

PubMed

Harrikari, Timo

2014-10-01

This article addresses the question of the structure of local child welfare activities in light of community-level factors. It poses the following research questions: how are different community-level factors related to child welfare client structures in communities and what is the extent to which these factors explain structural differences? The applied theoretical framework is based on social disorganization and strain theories as well as human developmental approach. The data has been collected from two Finnish national databases and it consists of variables containing 257 Finnish municipalities. The method of analysis is multinomial logistic regression. The results suggest that the local child welfare structures are tied to social disorganization, policing and culture as well as to the intensity of control in the communities. In general, the more fragile the communal structures, the more last-resort child welfare there is in the community. Combining fragile communal structures with weak dependency ratio and high proportion of social workers, the more intense the level of child welfare statistics indicated. The results indicate that the theoretical framework for the application of child welfare activity analysis is justified, but they also suggest that it requires further development through both context-bound reflection and application. Copyright © 2014 Elsevier Ltd. All rights reserved.

Explaining occupational class differences in sickness absence: results from middle-aged municipal employees.

PubMed

Laaksonen, M; Piha, K; Rahkonen, O; Martikainen, P; Lahelma, E

2010-09-01

Low socioeconomic position is consistently associated with higher rates of sickness absence. We aimed to examine whether working conditions, health-related behaviours and family-related factors explain occupational class differences in medically certified sickness absence. The study included 5470 women and 1464 men employees of the City of Helsinki, surveyed in 2000-2002. These data were prospectively linked to sickness absence records until the end of 2005, providing a mean follow-up time of 3.9 years. Poisson regression was used to examine the occurrence of medically certified sickness absence episodes lasting 4 days or more. Medically certified sickness absence was roughly three times more common among manual workers than among managers and professionals in both women and men. Physical working conditions were the strongest explanatory factors for occupational class differences in sickness absence, followed by smoking and relative weight. Work arrangements and family-related factors had very small effects only. The effects of psychosocial working conditions were heterogeneous: job control narrowed occupational class differences in sickness absence while mental strain and job demands tended to widened them. Overall, the findings were quite similar in women and men. Physical working conditions provided strongest explanations for occupational class differences in sickness absence. Smoking and relative weight, which are well-known determinants of health, also explained part of the excess sickness absence in lower occupational classes. Applying tailored work arrangements to employees on sick leave, reducing physically heavy working conditions and promoting healthy behaviours provide potential routes to narrow occupational class differences in sickness absence.

Personality traits and coping styles explain anxiety in lung cancer patients to a greater extent than other factors.

PubMed

Shimizu, Ken; Nakaya, Naoki; Saito-Nakaya, Kumi; Akechi, Tatsuo; Ogawa, Asao; Fujisawa, Daisuke; Sone, Toshimasa; Yoshiuchi, Kazuhiro; Goto, Koichi; Iwasaki, Motoki; Tsugane, Shoichiro; Uchitomi, Yosuke

2015-05-01

Although various factors thought to be correlated with anxiety in cancer patients, relative importance of each factors were unknown. We tested our hypothesis that personality traits and coping styles explain anxiety in lung cancer patients to a greater extent than other factors. A total of 1334 consecutively recruited lung cancer patients were selected, and data on cancer-related variables, demographic characteristics, health behaviors, physical symptoms and psychological factors consisting of personality traits and coping styles were obtained. The participants were divided into groups with or without a significant anxiety using the Hospital Anxiety and Depression Scale-Anxiety, and a binary logistic regression analysis was used to identify factors correlated with significant anxiety using a multivariate model. Among the recruited patients, 440 (33.0%) had significant anxiety. The binary logistic regression analysis revealed a coefficient of determination (overall R(2)) of 39.0%, and the explanation for psychological factors was much higher (30.7%) than those for cancer-related variables (1.1%), demographic characteristics (2.1%), health behaviors (0.8%) and physical symptoms (4.3%). Four specific factors remained significant in a multivariate model. A neurotic personality trait, a coping style of helplessness/hopelessness, and a female sex were positively correlated with significant anxiety, while a coping style of fatalism was negatively correlated. Our hypothesis was supported, and anxiety was strongly linked with personality trait and coping style. As a clinical implication, the use of screening instruments to identify these factors and intervention for psychological crisis may be needed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Peer and Individual Risk Factors in Adolescence Explaining the Relationship between Girls' Pubertal Timing and Teenage Childbearing

PubMed Central

Hendrick, C. Emily; Cance, Jessica Duncan; Maslowsky, Julie

2016-01-01

Girls with early pubertal timing are at elevated risk for teenage childbearing; however, the modifiable mechanisms driving this relationship are not well understood. The objective of the current study was to determine whether substance use, perceived peer substance use, and older first sexual partners mediate the relationships among girls' pubertal timing, sexual debut, and teenage childbearing. Data are from Waves 1 – 15 of the female cohort of the National Longitudinal Surveys of Youth 1997 (NLSY97), a nationwide, ongoing cohort study of U.S. men and women born between 1980 and 1984. The analytic sample (N=2,066) was 12-14 years old in 1997 and ethnically diverse (51% white, 27% black, 22% Latina). Using structural equation modeling, we found substance use in early adolescence and perceived peer substance use each partially mediated the relationships among girls' pubertal timing, sexual debut, and teenage childbearing. Our findings suggest early substance use behavior as one modifiable mechanism to be targeted by interventions aimed at preventing teenage childbearing among early developing girls. PMID:26769576

Peer and Individual Risk Factors in Adolescence Explaining the Relationship Between Girls' Pubertal Timing and Teenage Childbearing.

PubMed

Hendrick, C Emily; Cance, Jessica Duncan; Maslowsky, Julie

2016-05-01

Girls with early pubertal timing are at elevated risk for teenage childbearing; however, the modifiable mechanisms driving this relationship are not well understood. The objective of the current study was to determine whether substance use, perceived peer substance use, and older first sexual partners mediate the relationships among girls' pubertal timing, sexual debut, and teenage childbearing. Data are from Waves 1-15 of the female cohort of the National Longitudinal Surveys of Youth 1997 (NLSY97), a nationwide, ongoing cohort study of U.S. men and women born between 1980 and 1984. The analytic sample (n = 2066) was 12-14 years old in 1997 and ethnically diverse (51 % white, 27 % black, 22 % Latina). Using structural equation modeling, we found substance use in early adolescence and perceived peer substance use each partially mediated the relationships among girls' pubertal timing, sexual debut, and teenage childbearing. Our findings suggest early substance use behavior as one modifiable mechanism to be targeted by interventions aimed at preventing teenage childbearing among early developing girls.

Boosted Regression Tree Models to Explain Watershed ...

EPA Pesticide Factsheets

Boosted regression tree (BRT) models were developed to quantify the nonlinear relationships between landscape variables and nutrient concentrations in a mesoscale mixed land cover watershed during base-flow conditions. Factors that affect instream biological components, based on the Index of Biotic Integrity (IBI), were also analyzed. Seasonal BRT models at two spatial scales (watershed and riparian buffered area [RBA]) for nitrite-nitrate (NO2-NO3), total Kjeldahl nitrogen, and total phosphorus (TP) and annual models for the IBI score were developed. Two primary factors — location within the watershed (i.e., geographic position, stream order, and distance to a downstream confluence) and percentage of urban land cover (both scales) — emerged as important predictor variables. Latitude and longitude interacted with other factors to explain the variability in summer NO2-NO3 concentrations and IBI scores. BRT results also suggested that location might be associated with indicators of sources (e.g., land cover), runoff potential (e.g., soil and topographic factors), and processes not easily represented by spatial data indicators. Runoff indicators (e.g., Hydrological Soil Group D and Topographic Wetness Indices) explained a substantial portion of the variability in nutrient concentrations as did point sources for TP in the summer months. The results from our BRT approach can help prioritize areas for nutrient management in mixed-use and heavily impacted watershed

What factors explain pregnant women’s feeding intentions in Bradford, England: A multi-methods, multi-ethnic study

PubMed Central

2014-01-01

Background Using a multi-methods approach we aimed to explore the relative prediction of demographic, socioeconomic and modifiable predictors from the Theory of Planned behaviour (TPB) in explaining feeding intentions amongst a multi-ethnic sample. Methods 476 women completed a questionnaire at 28 weeks gestation. They were grouped into breastfeeding (N = 258), mixed-feeding (N = 50), bottle-feeding (N = 88) intenders, or a no clear intention (N = 88). Multinomial adjusted regressions explored the influence of modifiable TPB factors, along with ethnicity and socioeconomic status in predicting group membership. Free-text responses allowed women to elaborate on reasons behind their intention. Results TPB factors were significant predictors of feeding intention. Women with high intention to breastfeed were less likely to report high attitudes in any other feeding alternative. Bottle-feeding intenders reported poorer self-efficacy regarding breastfeeding compared to breastfeeding intenders (prevalence rate ratio, PRR = 0.10). Mixed and bottle-feeding intenders reported greater self-efficacy for mixed-feeding (PRR = 1.80, 5.50 respectively). Descriptive norms for mixed (PRR = 13.77) and bottle-feeding (PRR = 10.68) were predictive of mixed-feeding intention. Reasons for breastfeeding intentions related to health considerations, whilst bottle-feeding reasons related to convenience. Mixed-feeding intenders reported both breast and bottle-related factors. Conclusions Understanding modifiable predictors related to feeding intentions like TPB factors can help professionals target appropriate interventions to encourage breastfeeding. PMID:24472414

Explaining socioeconomic inequalities in exclusive breast feeding in Norway.

PubMed

Bærug, Anne; Laake, Petter; Løland, Beate Fossum; Tylleskär, Thorkild; Tufte, Elisabeth; Fretheim, Atle

2017-08-01

In high-income countries, lower socioeconomic position is associated with lower rates of breast feeding, but it is unclear what factors explain this inequality. Our objective was to examine the association between socioeconomic position and exclusive breast feeding, and to explore whether socioeconomic inequality in exclusive breast feeding could be explained by other sociodemographic characteristics, for example, maternal age and parity, smoking habits, birth characteristics, quality of counselling and breastfeeding difficulties. We used data from a questionnaire sent to mothers when their infants were five completed months as part of a trial of a breastfeeding intervention in Norway. We used maternal education as an indicator of socioeconomic position. Analyses of 1598 mother-infant pairs were conducted using logistic regression to assess explanatory factors of educational inequalities in breast feeding. Socioeconomic inequalities in exclusive breast feeding were present from the beginning and persisted for five completed months, when 22% of the most educated mothers exclusively breast fed compared with 7% of the least educated mothers: OR 3.39 (95% CI 1.74 to 6.61). After adjustment for all potentially explanatory factors, the OR was reduced to 1.49 (95% CI 0.70 to 3.14). This decrease in educational inequality seemed to be mainly driven by sociodemographic factors, smoking habits and breastfeeding difficulties, in particular perceived milk insufficiency. Socioeconomic inequalities in exclusive breast feeding at 5 months were largely explained by sociodemographic factors, but also by modifiable factors, such as smoking habits and breastfeeding difficulties, which can be amenable to public health interventions. NCT01025362. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Dynamic Factor Analysis of Nonstationary Multivariate Time Series.

ERIC Educational Resources Information Center

Molenaar, Peter C. M.; And Others

1992-01-01

The dynamic factor model proposed by P. C. Molenaar (1985) is exhibited, and a dynamic nonstationary factor model (DNFM) is constructed with latent factor series that have time-varying mean functions. The use of a DNFM is illustrated using data from a television viewing habits study. (SLD)

A Prominence Puzzle Explained?

NASA Astrophysics Data System (ADS)

Yeates, A. R.; Mackay, D. H.; van Ballegooijen, A. A.

2009-02-01

Long-standing observations reveal a global organisation of the magnetic field direction in solar prominences (aka filaments), large clouds of cool dense plasma suspended in the Sun's hot corona. However, theorists have thus far been unable to explain the origin of this hemispheric pattern. In particular, simple shearing by large-scale surface motions would appear to lead to the wrong magnetic field direction. To explain the observations, we have developed a new model of the global magnetic field evolution in the solar corona over six months. For the first time our model can follow the build-up of magnetic helicity and shear on a global scale, driven by flux emergence and surface motions. The model is successful in predicting the correct magnetic field direction in the vast majority of prominences tested, and has enabled us to determine the key physical mechanisms behind the mysterious hemispheric pattern.

DNA residence time is a regulatory factor of transcription repression

PubMed Central

Clauß, Karen; Popp, Achim P.; Schulze, Lena; Hettich, Johannes; Reisser, Matthias; Escoter Torres, Laura; Uhlenhaut, N. Henriette

2017-01-01

Abstract Transcription comprises a highly regulated sequence of intrinsically stochastic processes, resulting in bursts of transcription intermitted by quiescence. In transcription activation or repression, a transcription factor binds dynamically to DNA, with a residence time unique to each factor. Whether the DNA residence time is important in the transcription process is unclear. Here, we designed a series of transcription repressors differing in their DNA residence time by utilizing the modular DNA binding domain of transcription activator-like effectors (TALEs) and varying the number of nucleotide-recognizing repeat domains. We characterized the DNA residence times of our repressors in living cells using single molecule tracking. The residence times depended non-linearly on the number of repeat domains and differed by more than a factor of six. The factors provoked a residence time-dependent decrease in transcript level of the glucocorticoid receptor-activated gene SGK1. Down regulation of transcription was due to a lower burst frequency in the presence of long binding repressors and is in accordance with a model of competitive inhibition of endogenous activator binding. Our single molecule experiments reveal transcription factor DNA residence time as a regulatory factor controlling transcription repression and establish TALE-DNA binding domains as tools for the temporal dissection of transcription regulation. PMID:28977492

Factors associated with objectively measured total sedentary time and screen time in children aged 9-11 years.

PubMed

Ferrari, Gerson Luis de Moraes; Pires, Carlos; Solé, Dirceu; Matsudo, Victor; Katzmarzyk, Peter T; Fisberg, Mauro

2018-01-04

To identify factors associated with total sedentary time and screen time in children aged 9-11 years. For seven consecutive days, 328 children (51.5% boys) used accelerometers to monitor total sedentary time. Screen time was calculated by the self-reporting method. Individual, family, family environment, and school environment questionnaires were filled out. Body composition was measured using a Tanita scale. The mean sedentary time was 500min/day (boys: 489, girls: 511, p=0.005), and mean screen time was 234min/day (boys: 246, girls: 222, p=0.053). In both genders, factors associated with sedentary time were healthy dietary pattern and moderate-to-vigorous physical activity. In boys, only moderate-to-vigorous physical activity was significant; in girls, the healthy dietary pattern, moderate-to-vigorous physical activity, and transportation to school were significant. As for the screen time, the associated factors were body mass index and healthy dietary pattern (both genders). In boys, the associated factors were body mass index, healthy dietary pattern, and television in the bedroom. In girls, the associated factors were healthy dietary pattern, transportation to school, and physical activity policies or practice at school. Several associated factors were identified in the association between total sedentary time and screen time in children; however, only the healthy dietary pattern was common between sedentary time and screen time. Copyright © 2017. Published by Elsevier Editora Ltda.

Factors Influencing Part-time Faculty Engagement With Online Nursing Programs.

PubMed

Reneau, Margaret; Wallace, Cara; Claywell, Lora; Price, Jill; Burdi, Melissa; Trybulski, Joanne

2018-03-28

This research investigated factors that influenced the engagement of part-time faculty teaching in online nursing programs with their institutions. Of the 257 part-time faculty surveyed, the most significant factor was being supported in decisions regarding student issues, followed by institutional commitment to quality online education. Compensation was moderately influential; a negative factor was requiring too frequent meetings. Understanding factors that influence the engagement of part-time faculty teaching in online nursing programs can help leaders of online programs attract and retain experienced, highly skilled faculty.

Explaining social class differences in depression and well-being.

PubMed

Stansfeld, S A; Head, J; Marmot, M G

1998-01-01

Work characteristics, including skill discretion and decision authority, explain most of the socioeconomic status gradient in well-being and depression in middle-aged British civil servants from the Whitehall II Study, London. Social support explained about one-third of the gradient, life events and material difficulties less than one-third. Socioeconomic status was measured by employment grade. Work characteristics were based on the Karasek model, social support was measured by the Close Persons Questionnaire, depression by the General Health Questionnaire and well-being by the Affect Balance Scale. Despite a small contribution from social selective factors measured by upward mobility, the psychosocial work environment explained most of the cross-sectional socioeconomic status gradient in well-being and depression.

Explaining regional variation in home care use by demand and supply variables.

PubMed

van Noort, Olivier; Schotanus, Fredo; van de Klundert, Joris; Telgen, Jan

2018-02-01

In the Netherlands, home care services like district nursing and personal assistance are provided by private service provider organizations and covered by private health insurance companies which bear legal responsibility for purchasing these services. To improve value for money, their procurement increasingly replaces fee-for-service payments with population based budgets. Setting appropriate population budgets requires adaptation to the legitimate needs of the population, whereas historical costs are likely to be influenced by supply factors as well, not all of which are necessarily legitimate. Our purpose is to explain home care costs in terms of demand and supply factors. This allows for adjusting historical cost patterns when setting population based budgets. Using expenses claims of 60 Dutch municipalities, we analyze eight demand variables and five supply variables with a multiple regression model to explain variance in the number of clients per inhabitant, costs per client and costs per inhabitant. Our models explain 69% of variation in the number of clients per inhabitant, 28% of costs per client and 56% of costs per inhabitant using demand factors. Moreover, we find that supply factors explain an additional 17-23% of variation. Predictors of higher utilization are home care organizations that are integrated with intramural nursing homes, higher competition levels among home care organizations and the availability of complementary services. Copyright © 2017. Published by Elsevier B.V.

Multiple factors explain injury risk in adolescent elite athletes: Applying a biopsychosocial perspective.

PubMed

von Rosen, P; Frohm, A; Kottorp, A; Fridén, C; Heijne, A

2017-12-01

Many risk factors for injury are presented in the literature, few of those are however consistent and the majority is associated with adult and not adolescent elite athletes. The aim was to identify risk factors for injury in adolescent elite athletes, by applying a biopsychosocial approach. A total of 496 adolescent elite athletes (age range 15-19), participating in 16 different sports, were monitored repeatedly over 52 weeks using a valid questionnaire about injuries, training exposure, sleep, stress, nutrition, and competence-based self-esteem. Univariate and multiple Cox regression analyses were used to calculate hazard ratios (HR) for risk factors for first reported injury. The main finding was that an increase in training load, training intensity, and at the same time decreasing the sleep volume resulted in a higher risk for injury compared to no change in these variables (HR 2.25, 95% CI, 1.46-3.45, P<.01), which was the strongest risk factor identified. In addition, an increase by one score of competence-based self-esteem increased the hazard for injury with 1.02 (HR 95% CI, 1.00-1.04, P=.01). Based on the multiple Cox regression analysis, an athlete having the identified risk factors (Risk Index, competence-based self-esteem), with an average competence-based self-esteem score, had more than a threefold increased risk for injury (HR 3.35), compared to an athlete with a low competence-based self-esteem and no change in sleep or training volume. Our findings confirm injury occurrence as a result of multiple risk factors interacting in complex ways. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Breaking Down the Coercive Cycle: How Parent and Child Risk Factors Influence Real-Time Variability in Parental Responses to Child Misbehavior

PubMed Central

Lunkenheimer, Erika; Lichtwarck-Aschoff, Anna; Hollenstein, Tom; Kemp, Christine J.; Granic, Isabela

2016-01-01

Objective Parent-child coercive cycles have been associated with both rigidity and inconsistency in parenting behavior. To explain these mixed findings, we examined real-time variability in maternal responses to children's off-task behavior to determine whether this common trigger of the coercive cycle (responding to child misbehavior) is associated with rigidity or inconsistency in parenting. We also examined the effects of risk factors for coercion (maternal hostility, maternal depressive symptoms, child externalizing problems, and dyadic negativity) on patterns of parenting. Design Mother-child dyads (N = 96; M child age = 41 months) completed a difficult puzzle task, and observations were coded continuously for parent (e.g., directive, teaching) and child behavior (e.g., on-task, off-task). Results Multilevel continuous-time survival analyses revealed that parenting behavior is less variable when children are off-task. However, when risk factors are higher, a different profile emerges. Combined maternal and child risk is associated with markedly lower variability in parenting behavior overall (i.e., rigidity) paired with shifts towards higher variability specifically when children are off-task (i.e., inconsistency). Dyadic negativity (i.e., episodes when children are off-task and parents engage in negative behavior) are also associated with higher parenting variability. Conclusions Risk factors confer rigidity in parenting overall, but in moments when higher-risk parents must respond to child misbehavior, their parenting becomes more variable, suggesting inconsistency and ineffectiveness. This context-dependent shift in parenting behavior may help explain prior mixed findings and offer new directions for family interventions designed to reduce coercive processes. PMID:28190978

A human factors analysis of EVA time requirements

NASA Technical Reports Server (NTRS)

Pate, D. W.

1996-01-01

Human Factors Engineering (HFE), also known as Ergonomics, is a discipline whose goal is to engineer a safer, more efficient interface between humans and machines. HFE makes use of a wide range of tools and techniques to fulfill this goal. One of these tools is known as motion and time study, a technique used to develop time standards for given tasks. A human factors motion and time study was initiated with the goal of developing a database of EVA task times and a method of utilizing the database to predict how long an ExtraVehicular Activity (EVA) should take. Initial development relied on the EVA activities performed during the STS-61 mission (Hubble repair). The first step of the analysis was to become familiar with EVAs and with the previous studies and documents produced on EVAs. After reviewing these documents, an initial set of task primitives and task time modifiers was developed. Videotaped footage of STS-61 EVAs were analyzed using these primitives and task time modifiers. Data for two entire EVA missions and portions of several others, each with two EVA astronauts, was collected for analysis. Feedback from the analysis of the data will be used to further refine the primitives and task time modifiers used. Analysis of variance techniques for categorical data will be used to determine which factors may, individually or by interactions, effect the primitive times and how much of an effect they have.

Explaining direct care resource use of nursing home residents: findings from time studies in four states.

PubMed

Arling, Greg; Kane, Robert L; Mueller, Christine; Lewis, Teresa

2007-04-01

To explain variation in direct care resource use (RU) of nursing home residents based on the Resource Utilization Groups III (RUG-III) classification system and other resident- and unit-level explanatory variables. Primary data were collected on 5,314 nursing home residents in 156 nursing units in 105 facilities from four states (CO, IN, MN, MS) from 1998 to 2004. Study Design. Nurses and other direct care staff recorded resident-specific and other time caring for all residents on sampled nursing units. Care time was linked to resident data from the Minimum Data Set assessment instrument. Major variables were: RUG-III group (34-group), other health and functional conditions, licensed and other professional minutes per day, unlicensed minutes per day, and direct care RU (wage-weighted minutes). Resident- and unit-level relationships were examined through hierarchical linear modeling. Time study data were recorded with hand-held computers, verified for accuracy by project staff at the data collection sites and then merged into resident and unit-level data sets. Resident care time and RU varied between and within nursing units. RUG-III group was related to RU; variables such as length of stay and unit percentage of high acuity residents also were significantly related. Case-mix indices (CMIs) constructed from study data displayed much less variation across RUG-III groups than CMIs from earlier time studies. Results from earlier time studies may not be representative of care patterns of Medicaid and private pay residents. New RUG-III CMIs should be developed to better reflect the relative costs of caring for these residents.

Apolipoprotein E polymorphism in elderly Japanese-Brazilian immigrants does not explain the reduced cardiovascular risk factor incidence.

PubMed

Terra, N; Moriguchi, Y; Bittencourt, L; Trois, R S; Piccoli, J E C; Cruz, I B M

2011-09-09

Study of immigrant populations may contribute to a better understanding of the epidemiology of diseases associated with the aging process. We examined the prevalence of cardiovascular risk factors, including apolipoprotein E (ApoE) polymorphism, in elderly subjects who were born in Japan, migrated to South Brazil and have lived in that region for over 40 years, versus a group of elderly, locally born Brazilians living in the same region. These Japanese subjects came to Brazil after World War II (1950-1960) from several Japanese cities, mainly Nagasaki, Kumamoto and Hokkaido. Among 1007 subjects genotyped for ApoE polymorphism, we selected 540 elderly subjects (>60 years old), consisting of 270 Japanese-Brazilians and 270 Brazilians of European ancestry from Rio Grande do Sul State (Gaucha population). The Japanese-Brazilian group had significantly lower prevalences of obesity, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome than did the Gaucho population group. ApoE polymorphism frequencies were similar in the two groups. The differences in cardiovascular risk factors observed in the two populations cannot be explained by ApoE polymorphism; they could be related to conservation of Japanese lifestyle habits, such as diet.

Factors influencing time-location patterns and their impact on estimates of exposure: the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air).

PubMed

Spalt, Elizabeth W; Curl, Cynthia L; Allen, Ryan W; Cohen, Martin; Williams, Kayleen; Hirsch, Jana A; Adar, Sara D; Kaufman, Joel D

2016-06-01

We assessed time-location patterns and the role of individual- and residential-level characteristics on these patterns within the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) cohort and also investigated the impact of individual-level time-location patterns on individual-level estimates of exposure to outdoor air pollution. Reported time-location patterns varied significantly by demographic factors such as age, gender, race/ethnicity, income, education, and employment status. On average, Chinese participants reported spending significantly more time indoors and less time outdoors and in transit than White, Black, or Hispanic participants. Using a tiered linear regression approach, we predicted time indoors at home and total time indoors. Our model, developed using forward-selection procedures, explained 43% of the variability in time spent indoors at home, and incorporated demographic, health, lifestyle, and built environment factors. Time-weighted air pollution predictions calculated using recommended time indoors from USEPA overestimated exposures as compared with predictions made with MESA Air participant-specific information. These data fill an important gap in the literature by describing the impact of individual and residential characteristics on time-location patterns and by demonstrating the impact of population-specific data on exposure estimates.

Cognitive Factors Affecting Student Understanding of Geologic Time.

ERIC Educational Resources Information Center

Dodick, Jeff; Orion, Nir

2003-01-01

Presents a model that describes how students reconstruct geological transformations over time. Defines the critical factors influencing reconstructive thinking: (1) the transformation scheme, which influences the other diachronic schemes; (2) knowledge of geological processes; and (3) extracognitive factors. (Author/KHR)

Genetic pleiotropy explains associations between musical auditory discrimination and intelligence.

PubMed

Mosing, Miriam A; Pedersen, Nancy L; Madison, Guy; Ullén, Fredrik

2014-01-01

Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions.

Genetic Pleiotropy Explains Associations between Musical Auditory Discrimination and Intelligence

PubMed Central

Mosing, Miriam A.; Pedersen, Nancy L.; Madison, Guy; Ullén, Fredrik

2014-01-01

Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions. PMID:25419664

Does Social Capital Explain Community-Level Differences in Organ Donor Designation?

PubMed Central

Ladin, Keren; Wang, Rui; Fleishman, Aaron; Boger, Matthew; Rodrigue, James R

2015-01-01

Context The growing shortage of organs has reached unprecedented levels. Despite national attempts to increase donation and federal laws mandating the equitable allocation of organs, their availability and waiting times vary significantly nationwide. Organ donor designation is a collective action problem in public health, in which the regional organ supply and average waiting times are determined by the willingness of individuals to be listed as organ donors. Social capital increases the probability of collective action by fostering norms of reciprocity and cooperation while increasing costs to defectors. We examine whether social capital and other community-level factors explain geographic variation in organ donor designation rates in Massachusetts. Methods We obtained a sample of 3,281,532 registered drivers in 2010 from the Massachusetts Department of Transportation Registry of Motor Vehicles (MassDOT RMV). We then geocoded the registry data, matched them to 4,466 census blocks, and linked them to the 2010 US Census, the American Community Survey (ACS), and other sources to obtain community-level sociodemographic, social capital (residential segregation, voter registration and participation, residential mobility, violent-death rate), and religious characteristics. We used spatial modeling, including lagged variables to account for the effect of adjacent block groups, and multivariate regression analysis to examine the relationship of social capital and community-level characteristics with organ donor designation rates. Findings Block groups with higher levels of social capital, racial homogeneity, income, workforce participation, owner-occupied housing, native-born residents, and white residents had higher rates of organ donor designation (p < 0.001). These factors remained significant in the multivariate model, which explained more than half the geographic variance in organ donor designation (R2 = 0.52). Conclusions The findings suggest that community

A simple model of entropy relaxation for explaining effective activation energy behavior below the glass transition temperature.

PubMed

Bisquert, Juan; Henn, François; Giuntini, Jean-Charles

2005-03-01

Strong changes in relaxation rates observed at the glass transition region are frequently explained in terms of a physical singularity of the molecular motions. We show that the unexpected trends and values for activation energy and preexponential factor of the relaxation time tau, obtained at the glass transition from the analysis of the thermally stimulated current signal, result from the use of the Arrhenius law for treating the experimental data obtained in nonstationary experimental conditions. We then demonstrate that a simple model of structural relaxation based on a time dependent configurational entropy and Adam-Gibbs relaxation time is sufficient to explain the experimental behavior, without invoking a kinetic singularity at the glass transition region. The pronounced variation of the effective activation energy appears as a dynamic signature of entropy relaxation that governs the change of relaxation time in nonstationary conditions. A connection is demonstrated between the peak of apparent activation energy measured in nonequilibrium dielectric techniques, with the overshoot of the dynamic specific heat that is obtained in calorimetry techniques.

Sparkling feather reflections of a bird-of-paradise explained by finite-difference time-domain modeling.

PubMed

Wilts, Bodo D; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G

2014-03-25

Birds-of-paradise are nature's prime examples of the evolution of color by sexual selection. Their brilliant, structurally colored feathers play a principal role in mating displays. The structural coloration of both the occipital and breast feathers of the bird-of-paradise Lawes' parotia is produced by melanin rodlets arranged in layers, together acting as interference reflectors. Light reflection by the silvery colored occipital feathers is unidirectional as in a classical multilayer, but the reflection by the richly colored breast feathers is three-directional and extraordinarily complex. Here we show that the reflection properties of both feather types can be quantitatively explained by finite-difference time-domain modeling using realistic feather anatomies and experimentally determined refractive index dispersion values of keratin and melanin. The results elucidate the interplay between avian coloration and vision and indicate tuning of the mating displays to the spectral properties of the avian visual system.

Unravelling gossamer with boxing gloves: problems in explaining the decline in smoking.

PubMed Central

Chapman, S

1993-01-01

For about three decades countries such as Australia, Great Britain, and the United States have been turning up the heat on tobacco advertising. Encouraging, sometimes dramatic falls in consumption have followed. On any given day in 1993 smokers in such countries are exposed to a welter of news, information, persuasion, and policies designed to turn them off smoking. For a long time explanations and evaluations of the effects of these policies and interventions have been tied to oversimplified causal models when the reality is rather more messy and complicated. Four factors largely explain the reluctance of researchers to move beyond these models: the reductionist tradition of science; the explanatory privileging of recent events and factors; pragmatic concern for policy "tractable" factors; and the relation of funding to the evaluative process. Broader research approaches to understanding changes in complex behaviours such as smoking are required--for example, qualitative methods. Images p431-a p432-a PMID:8374457

Dynamic Factor Analysis Models with Time-Varying Parameters

ERIC Educational Resources Information Center

Chow, Sy-Miin; Zu, Jiyun; Shifren, Kim; Zhang, Guangjian

2011-01-01

Dynamic factor analysis models with time-varying parameters offer a valuable tool for evaluating multivariate time series data with time-varying dynamics and/or measurement properties. We use the Dynamic Model of Activation proposed by Zautra and colleagues (Zautra, Potter, & Reich, 1997) as a motivating example to construct a dynamic factor…

Explaining Direct Care Resource Use of Nursing Home Residents: Findings from Time Studies in Four States

PubMed Central

Arling, Greg; Kane, Robert L; Mueller, Christine; Lewis, Teresa

2007-01-01

Objective To explain variation in direct care resource use (RU) of nursing home residents based on the Resource Utilization Groups III (RUG-III) classification system and other resident- and unit-level explanatory variables. Data Sources/Study Setting Primary data were collected on 5,314 nursing home residents in 156 nursing units in 105 facilities from four states (CO, IN, MN, MS) from 1998 to 2004. Study Design Nurses and other direct care staff recorded resident-specific and other time caring for all residents on sampled nursing units. Care time was linked to resident data from the Minimum Data Set assessment instrument. Major variables were: RUG-III group (34-group), other health and functional conditions, licensed and other professional minutes per day, unlicensed minutes per day, and direct care RU (wage-weighted minutes). Resident- and unit-level relationships were examined through hierarchical linear modeling. Data Collection/Extraction Methods Time study data were recorded with hand-held computers, verified for accuracy by project staff at the data collection sites and then merged into resident and unit-level data sets. Principal Findings Resident care time and RU varied between and within nursing units. RUG-III group was related to RU; variables such as length of stay and unit percentage of high acuity residents also were significantly related. Case-mix indices (CMIs) constructed from study data displayed much less variation across RUG-III groups than CMIs from earlier time studies. Conclusions Results from earlier time studies may not be representative of care patterns of Medicaid and private pay residents. New RUG-III CMIs should be developed to better reflect the relative costs of caring for these residents. PMID:17362220

Modeling factors explaining physicians' satisfaction with competence.

PubMed

Lepnurm, Rein; Dobson, Roy Thomas; Peña-Sánchez, Juan-Nicolás; Nesdole, Robert

2015-01-01

Attention to physician wellness has increased as medical practice gains in complexity. Physician satisfaction with practice is critical for quality of care and practice growth. The purpose of this study was to model physicians' self-reported Satisfaction with Competence as a function of their perceptions of the Quality of Health Services, Distress, Coping, Practice Management, Personal Satisfaction and Professional Equity. Comprehensive questionnaires were sent to a stratified sample of 5300 physicians across Canada. This cross-sectional study focused on physicians who examined and treated individual patients for a final study population of 2639 physicians. Response bias was negligible. The questionnaires contained measures of Satisfaction with Competence, Quality of Health Services, Distress, Coping, Personal Satisfaction, Practice Management and Professional Equity. Exploring relationships was done using Pearson correlations and one-way analysis of variance. Modeling was by hierarchical regressions. The measures were reliable: Satisfaction with Competence (α = .86), Quality (α = .86), Access (α = .82), Distress (α = .82), Coping (α = .76), Personal Satisfaction (α = .78), Practice Management (α = .89) and the dimensions of Professional Equity (Fulfillment, α = .81; Financial, α = .93; and Recognition, α = .75) with comparative validity. Satisfaction with Competence was positively correlated with Quality (r = .32), Efficiency (r = .37) and Access (r = .32); negatively correlated with Distress (r = -.54); and positively correlated with Coping strategies (r = .43), Personal Satisfaction (r = .57), Practice Management (r = .17), Fulfillment (r = .53), Financial (r = .36) and Recognition (r = .54). Physicians' perceptions on Quality, Efficiency, Access, Distress, Coping, Personal Satisfaction, Practice Management, Fulfillment, Pay and Recognition explained 60.2% of the variation

Does Gene Tree Discordance Explain the Mismatch between Macroevolutionary Models and Empirical Patterns of Tree Shape and Branching Times?

PubMed Central

Stadler, Tanja; Degnan, James H.; Rosenberg, Noah A.

2016-01-01

Classic null models for speciation and extinction give rise to phylogenies that differ in distribution from empirical phylogenies. In particular, empirical phylogenies are less balanced and have branching times closer to the root compared to phylogenies predicted by common null models. This difference might be due to null models of the speciation and extinction process being too simplistic, or due to the empirical datasets not being representative of random phylogenies. A third possibility arises because phylogenetic reconstruction methods often infer gene trees rather than species trees, producing an incongruity between models that predict species tree patterns and empirical analyses that consider gene trees. We investigate the extent to which the difference between gene trees and species trees under a combined birth–death and multispecies coalescent model can explain the difference in empirical trees and birth–death species trees. We simulate gene trees embedded in simulated species trees and investigate their difference with respect to tree balance and branching times. We observe that the gene trees are less balanced and typically have branching times closer to the root than the species trees. Empirical trees from TreeBase are also less balanced than our simulated species trees, and model gene trees can explain an imbalance increase of up to 8% compared to species trees. However, we see a much larger imbalance increase in empirical trees, about 100%, meaning that additional features must also be causing imbalance in empirical trees. This simulation study highlights the necessity of revisiting the assumptions made in phylogenetic analyses, as these assumptions, such as equating the gene tree with the species tree, might lead to a biased conclusion. PMID:26968785

Interactions of psychosocial factors with built environments in explaining adolescents' active transportation.

PubMed

Wang, Xiaobo; Conway, Terry L; Cain, Kelli L; Frank, Lawrence D; Saelens, Brian E; Geremia, Carrie; Kerr, Jacqueline; Glanz, Karen; Carlson, Jordan A; Sallis, James F

2017-07-01

The present study examined independent and interacting associations of psychosocial and neighborhood built environment variables with adolescents' reported active transportation. Moderating effects of adolescent sex were explored. Mixed-effects regression models were conducted on data from the Teen Environment and Neighborhood observational study (N=928) in the Seattle, WA and Baltimore regions 2009-2011. Frequency index of active transportation to neighborhood destinations (dependent variable) and 7 psychosocial measures were reported by adolescents. Built environment measures included home walkability and count of nearby parks and recreation facilities using GIS procedures and streetscape quality from environmental audits. Results indicated all 3 environmental variables and 3 psychosocial variables (self-efficacy, social support from peers, and enjoyment of physical activity) had significant positive main effects with active transportation (Ps<0.05). Three of 21 two-way interactions were significant in explaining active transportation (Ps<0.1): self-efficacy×GIS-based walkability index, barriers to activity in neighborhood×MAPS streetscape scores, and self-efficacy×GIS-based counts of parks and recreation facilities. In each two-way interaction the highest active transportation was found among adolescents with the combination of activity-supportive built environment and positive psychosocial characteristics. Three-way interactions with sex indicated similar associations for girls and boys, with one exception. Results provided modest support for the ecological model principle of interactions across levels, highlight the importance of both built environment and psychosocial factors in shaping adolescents' active transportation, demonstrated the possibility of sex-specific findings, and suggested strategies for improving adolescents' active transportation may be most effective when targeting multiple levels of influence. Copyright © 2017 Elsevier Inc. All rights

Factors explaining priority setting at community mental health centres: a quantitative analysis of referral assessments.

PubMed

Grepperud, Sverre; Holman, Per Arne; Wangen, Knut Reidar

2014-12-14

Clinicians at Norwegian community mental health centres assess referrals from general practitioners and classify them into three priority groups (high priority, low priority, and refusal) according to need where need is defined by three prioritization criteria (severity, effect, and cost-effectiveness). In this study, we seek to operationalize the three criteria and analyze to what extent they have an effect on clinical-level priority setting after controlling for clinician characteristics and organisational factors. Twenty anonymous referrals were rated by 42 admission team members employed at 14 community mental health centres in the South-East Health Region of Norway. Intra-class correlation coefficients were calculated and logistic regressions were performed. Variation in clinicians' assessments of the three criteria was highest for effect and cost-effectiveness. An ordered logistic regression model showed that all three criteria for prioritization, three clinician characteristics (education, being a manager or not, and "guideline awareness"), and the centres themselves (fixed effects), explained priority decisions. The relative importance of the explanatory factors, however, depended on the priority decision studied. For the classification of all admitted patients into high- and low-priority groups, all clinician characteristics became insignificant. For the classification of patients, into those admitted and non-admitted, one criterion (effect) and "being a manager or not" became insignificant, while profession ("being a psychiatrist") became significant. Our findings suggest that variation in priority decisions can be reduced by: (i) reducing the disagreement in clinicians' assessments of cost-effectiveness and effect, and (ii) restricting priority decisions to clinicians with a similar background (education, being a manager or not, and "guideline awareness").

Explaining interindividual differences in toddlers' collaboration with unfamiliar peers: individual, dyadic, and social factors

PubMed Central

Schuhmacher, Nils; Kärtner, Joscha

2015-01-01

During their third year of life, toddlers become increasingly skillful at coordinating their actions with peer partners and they form joint commitments in collaborative situations. However, little effort has been made to explain interindividual differences in collaboration among toddlers. Therefore, we examined the relative influence of distinct individual, dyadic, and social factors on toddlers' collaborative activities (i.e., level of coordination and preference for joint activity) in joint problem-solving situations with unfamiliar peer partners (n = 23 dyads aged M = 35.7 months). We analyzed the dyadic nonindependent data with mixed models. Results indicated that mothers' expectations regarding their children's social behaviors significantly predicted toddlers' level of coordination. Furthermore, the models revealed that toddlers' positive mutual experiences with the unfamiliar partner assessed during an initial free play period (Phase 1) and their level of coordination in an obligatory collaboration task (Phase 2) promoted toddlers' preference for joint activity in a subsequent optional collaboration task (Phase 3). In contrast, children's mastery motivation and shyness conflicted with their collaborative efforts. We discuss the role of parents' socialization goals in toddlers' development toward becoming active collaborators and discuss possible mechanisms underlying the differences in toddlers' commitment to joint activities, namely social preferences and the trust in reliable cooperation partners. PMID:25983696

Factors Influencing Amount of Weekly Exercise Time in Colorectal Cancer Survivors.

PubMed

Chou, Yun-Jen; Lai, Yeur-Hur; Lin, Been-Ren; Liang, Jin-Tung; Shun, Shiow-Ching

Performing regular exercise of at least 150 minutes weekly has benefits for colorectal cancer survivors. However, barriers inhibit these survivors from performing regular exercise. The aim of this study was to explore exercise behaviors and significant factors influencing weekly exercise time of more than 150 minutes in colorectal cancer survivors. A cross-sectional study design was used to recruit participants in Taiwan. Guided by the ecological model of health behavior, exercise barriers were assessed including intrapersonal, interpersonal, and environment-related barriers. A multiple logistic regression was used to explore the factors associated with the amount of weekly exercise. Among 321 survivors, 57.0% of them had weekly exercise times of more than 150 minutes. The results identified multiple levels of significant factors related to weekly exercise times including intrapersonal factors (occupational status, functional status, pain, interest in exercise, and beliefs about the importance of exercise) and exercise barriers related to environmental factors (lack of time and bad weather). No interpersonal factors were found to be significant. Colorectal cancer survivors experienced low levels of physical and psychological distress. Multiple levels of significant factors related to exercise time including intrapersonal factors as well as exercise barriers related to environmental factors should be considered. Healthcare providers should discuss with their patients how to perform exercise programs; the discussion should address multiple levels of the ecological model such as any pain problems, functional status, employment status, and time limitations, as well as community environment.

Explaining ideology: two factors are better than one.

PubMed

Robbins, Philip; Shields, Kenneth

2014-06-01

Hibbing et al. contend that individual differences in political ideology can be substantially accounted for in terms of differences in a single psychological factor, namely, strength of negativity bias. We argue that, given the multidimensional structure of ideology, a better explanation of ideological variation will take into account both individual differences in negativity bias and differences in empathic concern.

Motor selection dynamics in FEF explain the reaction time variance of saccades to single targets

PubMed Central

Hauser, Christopher K; Zhu, Dantong; Stanford, Terrence R

2018-01-01

In studies of voluntary movement, a most elemental quantity is the reaction time (RT) between the onset of a visual stimulus and a saccade toward it. However, this RT demonstrates extremely high variability which, in spite of extensive research, remains unexplained. It is well established that, when a visual target appears, oculomotor activity gradually builds up until a critical level is reached, at which point a saccade is triggered. Here, based on computational work and single-neuron recordings from monkey frontal eye field (FEF), we show that this rise-to-threshold process starts from a dynamic initial state that already contains other incipient, internally driven motor plans, which compete with the target-driven activity to varying degrees. The ensuing conflict resolution process, which manifests in subtle covariations between baseline activity, build-up rate, and threshold, consists of fundamentally deterministic interactions, and explains the observed RT distributions while invoking only a small amount of intrinsic randomness. PMID:29652247

Sparkling feather reflections of a bird-of-paradise explained by finite-difference time-domain modeling

PubMed Central

Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

2014-01-01

Birds-of-paradise are nature’s prime examples of the evolution of color by sexual selection. Their brilliant, structurally colored feathers play a principal role in mating displays. The structural coloration of both the occipital and breast feathers of the bird-of-paradise Lawes’ parotia is produced by melanin rodlets arranged in layers, together acting as interference reflectors. Light reflection by the silvery colored occipital feathers is unidirectional as in a classical multilayer, but the reflection by the richly colored breast feathers is three-directional and extraordinarily complex. Here we show that the reflection properties of both feather types can be quantitatively explained by finite-difference time-domain modeling using realistic feather anatomies and experimentally determined refractive index dispersion values of keratin and melanin. The results elucidate the interplay between avian coloration and vision and indicate tuning of the mating displays to the spectral properties of the avian visual system. PMID:24591592

The limits of a limited future time perspective in explaining age differences in emotional functioning.

PubMed

Grühn, Daniel; Sharifian, Neika; Chu, Qiao

2016-09-01

Although a limited future time perspective (FTP) has been theorized to be the underlying mechanism of positive emotional functioning later in life, there is scant empirical evidence for this position. Using an integrative data-analytic approach, we investigated the predictive value of FTP, age, and subjective health in explaining emotional functioning in a sample of 2,504 adults (17 to 87 years, M = 35.5, SD = 14.2). Although older adults reported a more limited FTP than younger adults, age and a limited FTP had opposite effects in predicting subjective well-being, affect, positive emotions, empathy, and attitudes toward emotions. That is, old age was linked to a more adaptive emotional profile, whereas a limited FTP was linked to a more maladaptive emotional profile. This was the case even after controlling for health-related aspects. The findings question the usage of FTP as an explanatory variable for observed age differences in emotional functioning. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Reference Canopy Stomatal Conductance Explains Spatiotemporal Patterns of Tree Transpiration

NASA Astrophysics Data System (ADS)

Loranty, M. M.; Mackay, D. S.; Ewers, B. E.; Kruger, E. L.; Traver, E.

2007-12-01

Increased heterogeneity in patterns of whole tree transpiration (EC) with increasing atmospheric vapor pressure deficit (D) suggests a dynamic response of sap flow velocity (JS) to environmental drivers. We hypothesized that differences in reference stomatal conductance (GSref), stomatal conductance at D = 1kPa, would explain the spatiotemporal dynamics of JS. Using a coupled model of plant hydraulic and biochemical processes we tested this hypothesis with sap flux data for 106 aspen ( Populus tremuloides) and 108 sugar maple ( Acer saccharum) trees collected from plots using in 2-D cyclic sampling scheme during the summer of 2005 in northern Wisconsin. Inverse modeling is used to estimate GSref for each tree. For each species, trees from across the ranges of JS and diameter distributions are compared. GSref explained temporal variability in spatial patterns of EC We explore several possible mechanistic explanations for differences in GSref among trees. Topoedaphic factors are considered to determine if location within a stand has an effect. We also consider competition with neighboring individuals as a possible explanation. Variations in GSref in aspen were explained in part by competition for light between neighboring individuals, while competition for light was not a significant factor for sugar maple. Based on simulation analysis we identify possible biochemical feedbacks as drivers of the variability in plant hydraulics. Other factors examined included micro-topography within both sites.

Explaining ethnic disparities in lung function among young adults: A pilot investigation

PubMed Central

Patel, Jaymini; Minelli, Cosetta; Burney, Peter G. J.

2017-01-01

Background Ethnic disparities in lung function have been linked mainly to anthropometric factors but have not been fully explained. We conducted a cross-sectional pilot study to investigate how best to study ethnic differences in lung function in young adults and evaluate whether these could be explained by birth weight and socio-economic factors. Methods We recruited 112 university students of White and South Asian British ethnicity, measured post-bronchodilator lung function, obtained information on respiratory symptoms and socio-economic factors through questionnaires, and acquired birth weight through data linkage. We regressed lung function against ethnicity and candidate predictors defined a priori using linear regression, and used penalised regression to examine a wider range of factors. We reviewed the implications of our findings for the feasibility of a larger study. Results There was a similar parental socio-economic environment and no difference in birth weight between the two ethnic groups, but the ethnic difference in FVC adjusted for sex, age, height, demi-span, father’s occupation, birth weight, maternal educational attainment and maternal upbringing was 0.81L (95%CI: -1.01 to -0.54L). Difference in body proportions did not explain the ethnic differences although parental immigration was an important predictor of FVC independent of ethnic group. Participants were comfortable with study procedures and we were able to link birth weight data to clinical measurements. Conclusion Studies of ethnic disparities in lung function among young adults are feasible. Future studies should recruit a socially more diverse sample and investigate the role of markers of acculturation in explaining such differences. PMID:28575113

A Human Factors Analysis of EVA Time Requirements

NASA Technical Reports Server (NTRS)

Pate, Dennis W.

1997-01-01

Human Factors Engineering (HFE) is a discipline whose goal is to engineer a safer, more efficient interface between humans and machines. HFE makes use of a wide range of tools and techniques to fulfill this goal. One of these tools is known as motion and time study, a technique used to develop time standards for given tasks. During the summer of 1995, a human factors motion and time study was initiated with the goals of developing a database of EVA task times and developing a method of utilizing the database to predict how long an EVA should take. Initial development relied on the EVA activities performed during the STS-61 (Hubble) mission. The first step of the study was to become familiar with EVA's, the previous task-time studies, and documents produced on EVA's. After reviewing these documents, an initial set of task primitives and task-time modifiers was developed. Data was collected from videotaped footage of two entire STS-61 EVA missions and portions of several others, each with two EVA astronauts. Feedback from the analysis of the data was used to further refine the primitives and modifiers used. The project was continued during the summer of 1996, during which data on human errors was also collected and analyzed. Additional data from the STS-71 mission was also collected. Analysis of variance techniques for categorical data was used to determine which factors may affect the primitive times and how much of an effect they have. Probability distributions for the various task were also generated. Further analysis of the modifiers and interactions is planned.

To what extent may the association between immigrant status and mental illness be explained by socioeconomic factors?

PubMed

Tinghög, Petter; Hemmingsson, Tomas; Lundberg, Ingvar

2007-12-01

Immigrants in Sweden have a higher rate of mental illness than the native Swedes. This study investigated to what extent the association between immigrant status and mental illness can be explained by a different distribution of known risk factors for impaired mental health between groups of immigrants and persons born in Sweden. The study is based on data from the Swedish PART-study, designed to identify risk factors for, and social consequences of, mental illness. The study population consists of a random sample of 10,423 Swedish citizens, whereof 1,109 were immigrants. The data was collected in the year 2000. The immigrants were divided into three groups based on country of origin (Scandinavians born outside Sweden, Europeans born outside Scandinavia, non-Europeans). The occurrence of mental illness among immigrants and native Swedes were compared not adjusting and adjusting for indicators of socioeconomic advantage/disadvantage (education, income, labour market position, etc). Mental illness was approximated with the WHO (ten) wellbeing index scale and depressive symptoms were measured with the major depression inventory scale (MDI). Immigrants' excess risk for low subjective wellbeing was completely accounted for by adjustment for known risk factors in all the immigrant groups. However, social-economic disadvantages could not account for the non-European immigrants' higher prevalence of depression (MDI), although the increased relative risk found in univariate analyses was substantially reduced. The findings in this study suggest that the association between immigrant status and mental illness appears above all to be an effect of a higher prevalence of social and economic disadvantage.

Modeling factors explaining physicians’ satisfaction with competence

PubMed Central

Lepnurm, Rein; Dobson, Roy Thomas; Peña-Sánchez, Juan-Nicolás; Nesdole, Robert

2015-01-01

Recognition explained 60.2% of the variation in Satisfaction with Competence, controlling for years in practice, self-reported health and duties of physicians. Conclusion: Satisfaction with Competence could be affected by excessive accumulation of duties, concerns about quality, efficiency, access, excessive distress, inadequate coping abilities, personal satisfaction with life as a physician, challenges in managing practices and persistent inequities among physicians. PMID:27092256

Do pre-employment influences explain the association between psychosocial factors at work and coronary heart disease? The Whitehall II study.

PubMed

Hintsa, Taina; Shipley, Martin J; Gimeno, David; Elovainio, Marko; Chandola, Tarani; Jokela, Markus; Keltikangas-Järvinen, Liisa; Vahtera, Jussi; Marmot, Michael G; Kivimäki, Mika

2010-05-01

To examine whether the association between psychosocial factors at work and incident coronary heart disease (CHD) is explained by pre-employment factors, such as family history of CHD, education, paternal education and social class, number of siblings and height. A prospective cohort study of 6435 British men aged 35-55 years at phase 1 (1985-1988) and free from prevalent CHD at phase 2 (1989-1990) was conducted. Psychosocial factors at work were assessed at phases 1 and 2 and mean scores across the two phases were used to determine long-term exposure. Selected pre-employment factors were assessed at phase 1. Follow-up for coronary death, first non-fatal myocardial infarction or definite angina between phase 2 and 1999 was based on clinical records (250 events, follow-up 8.7 years). The selected pre-employment factors were associated with risk for CHD: HRs (95% CI) were 1.33 (1.03 to 1.73) for family history of CHD, 1.18 (1.05 to 1.32) for each quartile decrease in height and 1.16 (0.99 to 1.35) for each category increase in number of siblings. Psychosocial work factors also predicted CHD: 1.72 (1.08 to 2.74) for low job control and 1.72 (1.10 to 2.67) for low organisational justice. Adjustment for pre-employment factors changed these associations by 4.1% or less. In this occupational cohort of British men, the association between psychosocial factors at work and CHD was largely independent of family history of CHD, education, paternal educational attainment and social class, number of siblings and height.

Critical scales to explain urban hydrological response: an application in Cranbrook, London

NASA Astrophysics Data System (ADS)

Cristiano, Elena; ten Veldhuis, Marie-Claire; Gaitan, Santiago; Ochoa Rodriguez, Susana; van de Giesen, Nick

2018-04-01

Rainfall variability in space and time, in relation to catchment characteristics and model complexity, plays an important role in explaining the sensitivity of hydrological response in urban areas. In this work we present a new approach to classify rainfall variability in space and time and we use this classification to investigate rainfall aggregation effects on urban hydrological response. Nine rainfall events, measured with a dual polarimetric X-Band radar instrument at the CAESAR site (Cabauw Experimental Site for Atmospheric Research, NL), were aggregated in time and space in order to obtain different resolution combinations. The aim of this work was to investigate the influence that rainfall and catchment scales have on hydrological response in urban areas. Three dimensionless scaling factors were introduced to investigate the interactions between rainfall and catchment scale and rainfall input resolution in relation to the performance of the model. Results showed that (1) rainfall classification based on cluster identification well represents the storm core, (2) aggregation effects are stronger for rainfall than flow, (3) model complexity does not have a strong influence compared to catchment and rainfall scales for this case study, and (4) scaling factors allow the adequate rainfall resolution to be selected to obtain a given level of accuracy in the calculation of hydrological response.

Risk factors for first time incidence sciatica: a systematic review.

PubMed

Cook, Chad E; Taylor, Jeffrey; Wright, Alexis; Milosavljevic, Steven; Goode, Adam; Whitford, Maureen

2014-06-01

Characteristically, sciatica involves radiating leg pain that follows a dermatomal pattern along the distribution of the sciatic nerve. To our knowledge, there are no studies that have investigated risk factors associated with first time incidence sciatica. The purpose of the systematic review was to identify the longitudinal risk factors associated with first time incidence sciatica and to report incidence rates for the condition. For the purposes of this review, first time incidence sciatica was defined as either of the following: 1) no prior history of sciatica or 2) transition from a pain-free state to sciatica. Studies included subjects of any age from longitudinal, observational, cohort designs. The study was a systematic review. Eight of the 239 articles identified by electronic search strategies met the inclusion criteria. Risk factors and their respective effect estimates were reported using descriptive analysis and the preferred reporting items for systematic reviews and meta-analyses guidelines. Modifiable risk factors included smoking, obesity, occupational factors and health status. Non-modifiable factors included age, gender and social class. Incidence rates varied among the included studies, in part reflecting the variability in the operationalized definition of sciatica but ranged from <1% to 37%. A majority of the identified risk factors associated with first time sciatica are modifiable, suggesting the potential benefits of primary prevention. In addition, those risk factors are also associated with unhealthy lifestyles, which may function concomitantly toward the development of sciatica. Sciatica as a diagnosis is inconsistently defined among studies. © 2013 John Wiley & Sons, Ltd.

Cross-immunity between strains explains the dynamical pattern of paramyxoviruses

PubMed Central

Bhattacharyya, Samit; Gesteland, Per H.; Korgenski, Kent; Bjørnstad, Ottar N.; Adler, Frederick R.

2015-01-01

Viral respiratory tract diseases pose serious public health problems. Our ability to predict and thus, be able to prepare for outbreaks is strained by the complex factors driving the prevalence and severity of these diseases. The abundance of diseases and transmission dynamics of strains are not only affected by external factors, such as weather, but also driven by interactions among viruses mediated by human behavior and immunity. To untangle the complex out-of-phase annual and biennial pattern of three common paramyxoviruses, Respiratory Syncytial Virus (RSV), Human Parainfluenza Virus (HPIV), and Human Metapneumovirus (hMPV), we adopt a theoretical approach that integrates ecological and immunological mechanisms of disease interactions. By estimating parameters from multiyear time series of laboratory-confirmed cases from the intermountain west region of the United States and using statistical inference, we show that models of immune-mediated interactions better explain the data than those based on ecological competition by convalescence. The strength of cross-protective immunity among viruses is correlated with their genetic distance in the phylogenetic tree of the paramyxovirus family. PMID:26460003

One-day quantitative cross-sectional study of family information time in 90 intensive care units in France.

PubMed

Fassier, Thomas; Darmon, Michel; Laplace, Christian; Chevret, Sylvie; Schlemmer, Benoit; Pochard, Frédéric; Azoulay, Elie

2007-01-01

Providing family members with clear, honest, and timely information is a major task for intensive care unit physicians. Time spent informing families has been associated with effectiveness of information but has not been measured in specifically designed studies. To measure time spent informing families of intensive care unit patients. One-day cross-sectional study in 90 intensive care units in France. Clocked time spent by physicians informing the families of each of 951 patients hospitalized in the intensive care unit during a 24-hr period. Median family information time was 16 (interquartile range, 8-30) mins per patient, with 20% of the time spent explaining the diagnosis, 20% on explaining treatments, and 60% on explaining the prognosis. One third of the time was spent listening to family members. Multivariable analysis identified one factor associated with less information time (room with more than one bed) and seven factors associated with more information time, including five patient-related factors (surgery on the study day, higher Logistic Organ Dysfunction score, coma, mechanical ventilation, and worsening clinical status) and two family-related factors (first contact with family and interview with the spouse). Median information time was 20 (interquartile range, 10-39) mins when three factors were present and 106.5 (interquartile range, 103-110) mins when five were present. This study identifies factors associated with information time provided by critical care physicians to family members of critically ill patients. Whether information time correlates with communication difficulties or communication skills needs to be evaluated. Information time provided by residents and nurses should be studied.

Trend surface models in the representation and analysis of time factors in cancer mortality.

PubMed

Cislaghi, C; Negri, E; La Vecchia, C; Levi, F

1990-01-01

A method of graphic representation of time factors in cancer mortality is presented, based on different tonalities of grey applied to the surface of the matrix defined by various age-specific rates. It is illustrated using mortality data from cancers of the mouth or pharynx, oesophagus, larynx and lung in Italian and Swiss males. Progressively more complex regression surface equations are defined, on the basis of two independent variables (age and cohort) and a dependent one (each age-specific rate). General patterns of trends were thus identified, showing important similarities in cohort and period effects, but also noticeable differences in time-related factors in mortality from various neoplasms of the upper digestive and respiratory tract. For instance, there were declines in mortality from cancers of the mouth or pharynx in the oldest age groups, whereas rates were appreciably upwards at younger and middle age, particularly in Italy. Likewise, cancers of the oesophagus and, chiefly, of the larynx were substantially increasing, on a cohort basis, in oldest Italian males. Temporal pattern for laryngeal cancer in Italy was similar to that of lung cancer, thus suggesting that (cigarette) smoking has a greater impact on this cancer site as compared with alcohol. However, it is difficult to explain, on this basis alone, the totally diverging pattern for cancer of the larynx (downwards) and of the lung (upwards) observed among older Swiss males. These examples indicate that trend surface models are a useful summary guide to illustrate and understand the general patterns of age, period and cohort effects in cancer mortality.

Do Differences in Risk Factors Explain the Lower Rates of Coronary Heart Disease in Japanese Versus U.S. Women?

PubMed Central

Willcox, Bradley J.; Usui, Takeshi; Carr, John Jeffrey; Barinas-Mitchell, Emma J.M.; Masaki, Kamal H.; Watanabe, Makoto; Tracy, Russell P.; Bertolet, Marianne H.; Evans, Rhobert W.; Nishimura, Kunihiko; Sutton-Tyrrell, Kim; Kuller, Lewis H.; Miyamoto, Yoshihiro

2013-01-01

Abstract Background Mortality from coronary heart disease (CHD) in women in Japan is one of the lowest in developed countries. In an attempt to shed some light on possible reasons of lower CHD in women in Japan compared with the United States, we extensively reviewed and analyzed existing national data and recent literature. Methods We searched recent epidemiological studies that reported incidence of acute myocardial infarction (AMI) and examined risk factors for CHD in women in Japan. Then, we compared trends in risk factors between women currently aged 50–69 years in Japan and the United States, using national statistics and other available resources. Results Recent epidemiological studies have clearly shown that AMI incidence in women in Japan is lower than that reported from other countries, and that lipids, blood pressure (BP), diabetes, smoking, and early menopause are independent risk factors. Comparing trends in risk factors between women in Japan and the United States, current levels of serum total cholesterol are higher in women in Japan and levels have been similar at least since 1990. Levels of BP have been higher in in Japan for the past 3 decades. Prevalence of type 2 diabetes has been similar in Japanese and white women currently aged 60–69 for the past 2 decades. In contrast, rates of cigarette smoking, although low in women in both countries, have been lower in women in Japan. Conclusions Differences in risk factors and their trends are unlikely to explain the difference in CHD rates in women in Japan and the United States. Determining the currently unknown factors responsible for low CHD mortality in women in Japan may lead to new strategy for CHD prevention. PMID:24073782

Proton Form Factors Measurements in the Time-Like Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anulli, F.; /Frascati

2007-10-22

I present an overview of the measurement of the proton form factors in the time-like region. BABAR has recently measured with great accuracy the e{sup +}e{sup -} {yields} p{bar p} reaction from production threshold up to an energy of {approx} 4.5 GeV, finding evidence for a ratio of the electric to magnetic form factor greater than unity, contrary to expectation. In agreement with previous measurements, BABAR confirmed the steep rise of the magnetic form factor close to the p{bar p} mass threshold, suggesting the possible presence of an under-threshold N{bar N} vector state. These and other open questions related tomore » the nucleon form factors both in the time-like and space-like region, wait for more data with different experimental techniques to be possibly solved.« less

Analysis of forecasting malaria case with climatic factors as predictor in Mandailing Natal Regency: a time series study

NASA Astrophysics Data System (ADS)

Aulia, D.; Ayu, S. F.; Matondang, A.

2018-01-01

Malaria is the most contagious global concern. As a public health problem with outbreaks, affect the quality of life and economy, also could lead to death. Therefore, this research is to forecast malaria cases with climatic factors as predictors in Mandailing Natal Regency. The total number of positive malaria cases on January 2008 to December 2016 were taken from health department of Mandailing Natal Regency. Climates data such as rainfall, humidity, and temperature were taken from Center of Statistic Department of Mandailing Natal Regency. E-views ver. 9 is used to analyze this study. Autoregressive integrated average, ARIMA (0,1,1) (1,0,0)12 is the best model to explain the 67,2% variability data in time series study. Rainfall (P value = 0.0005), temperature (P value = 0,0029) and humidity (P value = 0.0001) are significant predictors for malaria transmission. Seasonal adjusted factor (SAF) in November and March shows peak for malaria cases.

Factors influencing women's decisions about timing of motherhood.

PubMed

Benzies, Karen; Tough, Suzanne; Tofflemire, Karen; Frick, Corine; Faber, Alexandra; Newburn-Cook, Christine

2006-01-01

To examine the factors that influence women's decisions about the timing of motherhood from a life span perspective. Qualitative. Large Western Canadian city with a high rate of infants born to women aged 35 years and older. 45 Canadian women aged 20 to 48 years. Independence, a stable relationship, and declining fertility influenced women's decisions about the timing of motherhood. Women integrated child developmental transitions into a projected life plan as they considered the timing of motherhood. Partner readiness and family of origin influences played a lesser role. Delayed childbearing has become more socially acceptable, with subsequent negative connotations associated with younger motherhood. Parental benefits have limited influence on the timing of motherhood. Recognition by nurses of the various and complex factors that influence women's decisions about the timing of motherhood may flag the importance of pregnancy-related counseling for woman across the fertility life span. Policy decision makers must be cognizant of the need for additional high-risk obstetric and neonatal health services when societal norms encourage women to delay childbearing in favor of completing education and establishing a career. (c) 2006, AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses

Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion.

PubMed

Smith, Jennifer N; Emlen, Douglas J; Pearson, Dean E

2016-01-01

Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe's architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations.

Identifying factors associated with regular physical activity in leisure time among Canadian adolescents.

PubMed

Godin, Gaston; Anderson, Donna; Lambert, Léo-Daniel; Desharnais, Raymond

2005-01-01

The purpose of this study was to identify the factors explaining regular physical activity among Canadian adolescents. A cohort study conducted over a period of 2 years. A French-language high school located near Québec City. A cohort of 740 students (352 girls; 388 boys) aged 13.3 +/- 1.0 years at baseline. Psychosocial, life context, profile, and sociodemographic variables were assessed at baseline and 1 and 2 years after baseline. Exercising almost every day during leisure time at each measurement time was the dependent variable. The Generalized Estimating Equations (GEE) analysis indicated that exercising almost every day was significantly associated with a high intention to exercise (odds ratio [OR]: 8.33, confidence interval [CI] 95%: 5.26, 13.18), being satisfied with the activity practiced (OR: 2.07, CI 95%: 1.27, 3.38), perceived descriptive norm (OR: 1.82, CI 95%: 1.41, 2.35), being a boy (OR: 1.83, CI 95%: 1.37, 2.46), practicing "competitive" activities (OR: 1.80, CI 95%: 1.37, 2.36), eating a healthy breakfast (OR: 1.68, CI 95%: 1.09, 2.60), and normative beliefs (OR: 1.48, CI 95%: 1.14, 1.90). Specific GEE analysis for gender indicated slight but significant differences. This study provides evidence for the need to design interventions that are gender specific and that focus on increasing intention to exercise regularly.

Students' Development and Use of Models to Explain Electrostatic Interactions

NASA Astrophysics Data System (ADS)

Mayer, Kristin Elizabeth

The National Research Council (2012) recently published A Framework for K-12 Science Education that describes a vision for science classrooms where students engage in three dimensions--scientific and engineering practices, crosscutting concepts, and disciplinary core ideas--to explain phenomena or observations they can make about the universe around them. This vision of science instruction is a significant shift from current classroom instruction. This dissertation provides detailed examples of how students developed and used models to build causal explanations of phenomena. I co-taught classes that focused on having students develop and revise models of electric fields and atomic structure using a curriculum that was designed to align with the three-dimensional vision of learning. I developed case studies of eleven students from these classes. I analyzed the students' responses and interviewed the students throughout the school year. By comparing and contrasting the analysis across the analysis of students' interviews, I identified four themes: 1) students could apply their ideas to explain novel and abstract phenomena; 2) students struggled to connect changes in their atomic models to evidence, but ended up with dynamic models of atomic structure that they could apply to explain phenomena; 3) students developed models of atomic structure that they applied to explain phenomena, but they did not use models of electric fields in this way; and 4) too much focus on details interfered with students' ability to apply their models to explain new phenomena. This dissertation highlights the importance of focusing on phenomena in classrooms that aim at aligning with three-dimensional learning. Students struggled to focus on specific content and apply their ideas to explain phenomena at the same time. In order to apply ideas to new context, students had to shift their focus from recalling ideas to applying the ideas they do have. A focus on phenomena allowed students to show

Explaining mastitis incidence in Dutch dairy farming: the influence of farmers' attitudes and behaviour.

PubMed

Jansen, J; van den Borne, B H P; Renes, R J; van Schaik, G; Lam, T J G M; Leeuwis, C

2009-11-15

When mastitis incidence increases, either infection pressure has increased or cows' resistance has decreased. This usually indicates that farm management is not optimal. Numerous quantitative studies have demonstrated the effect of management practices on mastitis. In most of these studies, the identified risk factors could explain only part of the variance in mastitis incidence on farms. Several studies suggest that the unexplained variance is caused by farmers' attitudes towards different aspects of mastitis treatment and preventive behaviour. This study aims to determine, to quantify and to specify the extent to which farmers' attitudes, over and above farmers' behaviour, are factors that explain the variation in mastitis incidence, measured in terms of the quantifiable effect of management factors. An extensive survey on self-reported attitudes, behaviour and mastitis incidence was conducted on 336 Dutch dairy farms. Results of multiple linear regression analyses show that farmers' self-reported behaviour and attitudes together explain 48%, 31% and 23% of the variation within, respectively, the average farm bulk milk somatic cell count (BMSCC), the clinical mastitis incidence and the combined clinical and subclinical mastitis incidence. Both behaviour and attitudes explain part of the variance. However, most of the variance in all three dependant measures is explained solely by the attitude variables. The variation in BMSCC value is best explained by (1) farmers' normative frame of reference about mastitis, (2) farmers' perceptions about the control of mastitis and (3) the perceived effect of a BMSCC penalty level. The variation in clinical mastitis is best explained by farmers' perceptions about mastitis control. The variation in the combined clinical and subclinical mastitis incidence rate is best explained by the perceived effect of a BMSCC penalty level and the frequency of contact with others. The results of this study show that farmers' attitudes are a

Time-activity relationships to VOC personal exposure factors

NASA Astrophysics Data System (ADS)

Edwards, Rufus D.; Schweizer, Christian; Llacqua, Vito; Lai, Hak Kan; Jantunen, Matti; Bayer-Oglesby, Lucy; Künzli, Nino

Social and demographic factors have been found to play a significant role in differences between time-activity patterns of population subgroups. Since time-activity patterns largely influence personal exposure to compounds as individuals move across microenvironments, exposure subgroups within the population may be defined by factors that influence daily activity patterns. Socio-demographic and environmental factors that define time-activity subgroups also define quantifiable differences in VOC personal exposures to different sources and individual compounds in the Expolis study. Significant differences in exposures to traffic-related compounds ethylbenzene, m- and p-xylene and o-xylene were observed in relation to gender, number of children and living alone. Categorization of exposures further indicated time exposed to traffic at work and time in a car as important determinants. Increased exposures to decane, nonane and undecane were observed for males, housewives and self-employed. Categorization of exposures indicated exposure subgroups related to workshop use and living downtown. Higher exposures to 3-carene and α-pinene commonly found in household cleaning products and fragrances were associated with more children, while exposures to traffic compounds ethylbenzene, m- and p-xylene and o-xylene were reduced with more children. Considerable unexplained variation remained in categorization of exposures associated with home product use and fragrances, due to individual behavior and product choice. More targeted data collection methods in VOC exposure studies for these sources should be used. Living alone was associated with decreased exposures to 2-methyl-1-propanol and 1-butanol, and traffic-related compounds. Identification of these subgroups may help to reduce the large amount of unexplained variation in VOC exposure studies. Further they may help in assessing impacts of urban planning that result in changes in behavior of individuals, resulting in shifts in

On the explaining-away phenomenon in multivariate latent variable models.

PubMed

van Rijn, Peter; Rijmen, Frank

2015-02-01

Many probabilistic models for psychological and educational measurements contain latent variables. Well-known examples are factor analysis, item response theory, and latent class model families. We discuss what is referred to as the 'explaining-away' phenomenon in the context of such latent variable models. This phenomenon can occur when multiple latent variables are related to the same observed variable, and can elicit seemingly counterintuitive conditional dependencies between latent variables given observed variables. We illustrate the implications of explaining away for a number of well-known latent variable models by using both theoretical and real data examples. © 2014 The British Psychological Society.

Explaining Spatial Variability in Wellbore Impairment Risk for Pennsylvania Oil and Gas Wells, 2000-2014

NASA Astrophysics Data System (ADS)

Santoro, R.; Ingraffea, A. R.

2015-12-01

Previous modeling (ingraffea et al. PNAS, 2014) indicated roughly two-times higher cumulative risk for wellbore impairment in unconventional wells, relative to conventional wells, and large spatial variation in risk for oil and gas wells drilled in the state of Pennsylvania. Impairment risk for wells in the northeast portion of the state were found to be 8.5-times greater than that of wells drilled in the rest of the state. Here, we set out to explain this apparent regional variability through Boosted Regression Tree (BRT) analysis of geographic, developmental, and general well attributes. We find that regional variability is largely driven by the nature of the development, i.e. whether conventional or unconventional development is dominant. Oil and natural gas market prices and total well depths present as major influences in wellbore impairment, with moderate influences from well densities and geologic factors. The figure depicts influence paths for predictors of impairments for the state (top left), SW region (top right), unconventional/NE region (bottom left) and conventional/NW region (bottom right) models. Influences are scaled to reflect percent contributions in explaining variability in the model.

Increased volume of distribution for recombinant activated factor VII and longer plasma-derived factor VII half-life may explain their long lasting prophylactic effect.

PubMed

Mathijssen, Natascha C J; Masereeuw, Rosalinde; Holme, Pal Andre; van Kraaij, Marian G J; Laros-van Gorkom, Britta A P; Peyvandi, Flora; van Heerde, Waander L

2013-08-01

Prophylaxis with plasma-derived or recombinant activated factor VII is beneficial in severe factor VII deficiency. To understand why prophylactic treatment with both products is efficacious, we conducted a pharmacokinetic study. Ten factor VII deficient patients were treated with either recombinant activated (20 μg/kg) or plasma-derived (25 IU/kg) factor VII in a cross-over design. Pharmacokinetic parameters were analyzed through activated factor VII activity, factor VII clotting activity, and factor VII antigen levels on depicted time points. Factor VII activity half-lifes, determined by non-compartmental and one-compartmental analysis (results in brackets), were shorter for recombinant activated (1.4h; 0.7h) than for plasma-derived factor VII (6.8h; 3.2h); both recombinant activated (5.1h; 2.1h and plasma-derived factor VII (5.8h; 3.2h) resulted in longer half-lives of factor VII antigen. Activated factor VII half-lives (based on activated factor VII activity levels) were significantly higher compared to factor VII clotting activity (1.6h; 0.9h). Volumes of distribution were significantly higher for activated factor VII (236 ml/kg; 175 ml/kg, measured by activated factor VII) as compared to plasma-derived factor VII (206 ml/kg; 64 ml/kg, measured by factor FVII activity), suggesting a plasma- and extracellular fluid distribution for recombinant activated factor VII. Recombinant activated factor VII showed significantly shorter half-lifes than plasma-derived factor VII. Volumes of distribution were significantly higher for treatment with recombinant activated factor VII. The longer half-life for plasma-derived factor VII, compared to recombinant activated factor VII, and the increased volume of distribution for recombinant activated factor VII, compared to plasma-derived factor VII may further elucidate the beneficial effect of prophylactic treatment of both products. Copyright © 2013 Elsevier Ltd. All rights reserved.

Exploring the Factors Contributing to Sibling Correlations in BMI: A Study Using the Panel Study of Income Dynamics

PubMed Central

Brown, Heather W.; Roberts, Jennifer

2012-01-01

Understanding the mechanisms contributing to correlated BMI outcomes in a social network such as siblings will help policy makers reduce the burden of disease associated with obesity. There are two potential mechanisms explaining correlated BMI outcomes in a biologically related social network: (i) time constant factors such as genetic heritability and habits formed during childhood and (ii) factors that change over time some of which are dependent on the frequency of interactions between the social network, for example, social norms shaped by the social network's shifting attitudes towards weight and behaviors related to weight, or environmental factors like opportunities for exercise. This study aims to distinguish between time constant factors from factors that are likely to change over time to gain a better understanding of the mechanisms explaining the correlation in sibling BMI. We exploit data from the Panel Study of Income Dynamics (PSID) over 1999–2007 estimating the correlation in BMI for adult siblings who currently live in separate households but grew-up in the same household and adolescent siblings currently living in the same household to isolate the influence of factors that change over time. The findings indicate that time constant factors explain some of the overall correlation in sibling BMI for both cohorts of siblings. Factors that change over time only significantly impact on the overall correlation in BMI for adolescent siblings suggesting if there is a social network influence on correlations in BMI this is facilitated by sharing the same household. PMID:22173572

Explaining Racial Disparities in Infant Health in Brazil

PubMed Central

Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

2015-01-01

Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:26313046

Explaining Racial Disparities in Infant Health in Brazil

PubMed Central

Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

2013-01-01

Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:23409894

Invited commentary: Timing and types of cardiovascular risk factors in relation to offspring birth weight.

PubMed

Ness, Roberta B; Catov, Janet

2007-12-15

Birth weight is associated with later-life cardiovascular risk. A new study by Romundstad et al. (Am J Epidemiol 2007;166:1359-1364) challenges us to consider influences on birth weight with respect to timing and type. Timing of effects on birth weight, according to the "fetal origins hypothesis," is in utero. Alternatively, familial aggregation--genetics or shared environment--may explain birth weight and suggests prepregnancy influences. The Romundstad et al. findings support familial effects: maternal metabolic factors predicted birth weight for gestational age. However, because maternal physiology sets the fetal environment, these data do not necessarily counter the fetal origins hypothesis. Types of maternal metabolic influences demonstrated by Romundstad et al. include elevations in blood pressure being associated with lower birth weight for gestational age, whereas unfavorable glucose and lipid levels were associated with higher birth weight. These findings are consistent with the authors prior hypothesis that vascular dysfunction and metabolic profile (glucose and lipids) have divergent effects during pregnancy. Moreover, these new data underscore that both extremes of birth weight may be related to cardiovascular risk. Few data sets contain prepregnancy, pregnancy, and childhood information. Without all such time points, life course effects will remain only partially understood. It is hoped that studies such as the forthcoming National Children's Study will generate critical understanding of this issue.

Cognitive Abilities Explaining Age-Related Changes in Time Perception of Short and Long Durations

ERIC Educational Resources Information Center

Zelanti, Pierre S.; Droit-Volet, Sylvie

2011-01-01

The current study investigated how the development of cognitive abilities explains the age-related changes in temporal judgment over short and long duration ranges from 0.5 to 30 s. Children (5- and 9-year-olds) as well as adults were given a temporal bisection task with four different duration ranges: a duration range shorter than 1 s, two…

Adult mortality probability and nest predation rates explain parental effort in warming eggs with consequences for embryonic development time

USGS Publications Warehouse

Martin, Thomas E.; Oteyza, Juan C.; Boyce, Andy J.; Lloyd, Penn; Ton, Riccardo

2015-01-01

Parental behavior and effort vary extensively among species. Life-history theory suggests that age-specific mortality could cause this interspecific variation, but past tests have focused on fecundity as the measure of parental effort. Fecundity can cause costs of reproduction that confuse whether mortality is the cause or the consequence of parental effort. We focus on a trait, parental allocation of time and effort in warming embryos, that varies widely among species of diverse taxa and is not tied to fecundity. We conducted studies on songbirds of four continents and show that time spent warming eggs varies widely among species and latitudes and is not correlated with clutch size. Adult and offspring (nest) mortality explained most of the interspecific variation in time and effort that parents spend warming eggs, measured by average egg temperatures. Parental effort in warming eggs is important because embryonic temperature can influence embryonic development period and hence exposure time to predation risk. We show through correlative evidence and experimental swapping of embryos between species that parentally induced egg temperatures cause interspecific variation in embryonic development period. The strong association of age-specific mortality with parental effort in warming eggs and the subsequent effects on embryonic development time are unique results that can advance understanding of broad geographic patterns of life-history variation.

Timing of population peaks of Norway lemming in relation to atmospheric pressure: A hypothesis to explain the spatial synchrony.

PubMed

Selås, Vidar

2016-06-01

Herbivore cycles are often synchronized over larger areas than what could be explained by dispersal. In Norway, the 3-4 year lemming cycle usually show no more than a one-year time lag between different regions, despite distances of up to 1000 km. If important food plants are forced to reallocate defensive proteins in years with high seed production, spatially synchronized herbivore outbreaks may be due to climate-synchronized peaks in flowering. Because lemming peaks are expected to occur one year after a flowering peak, and the formation of flower buds is induced in the year before flowering, a two-year time lag between flower-inducing climate events and lemming peaks is predicted. At Hardangervidda, South Norway, the probability that a year was a population peak year of lemming during 1920-2014 increased with increasing midsummer atmospheric pressure two years earlier, even when the number of years since the previous peak was accounted for.

Can Science Explain the Human Mind? Intuitive Judgments About the Limits of Science.

PubMed

Gottlieb, Sara; Lombrozo, Tania

2018-01-01

Can science explain romantic love, morality, and religious belief? We documented intuitive beliefs about the limits of science in explaining the human mind. We considered both epistemic evaluations (concerning whether science could possibly fully explain a given psychological phenomenon) and nonepistemic judgments (concerning whether scientific explanations for a given phenomenon would generate discomfort), and we identified factors that characterize phenomena judged to fall beyond the scope of science. Across six studies, we found that participants were more likely to judge scientific explanations for psychological phenomena to be impossible and uncomfortable when, among other factors, they support first-person, introspective access (e.g., feeling empathetic as opposed to reaching for objects), contribute to making humans exceptional (e.g., appreciating music as opposed to forgetfulness), and involve conscious will (e.g., acting immorally as opposed to having headaches). These judgments about the scope of science have implications for science education, policy, and the public reception of psychological science.

Measurement of time processing ability and daily time management in children with disabilities.

PubMed

Janeslätt, Gunnel; Granlund, Mats; Kottorp, Anders

2009-01-01

Improvement is needed in methods for planning and evaluating interventions designed to facilitate daily time management for children with intellectual disability, Asperger syndrome, or other developmental disorders. The aim of this study was to empirically investigate the hypothesized relation between children's time processing ability (TPA), daily time management, and self-rated autonomy. Such a relationship between daily time management and TPA may support the idea that TPA is important for daily time management and that children with difficulties in TPA might benefit from intervention aimed at improving daily time management. Participants were children aged 6 to 11 years with dysfunctions such as attention-deficit/hyperactivity disorder, autism, or physical or intellectual disabilities (N = 118). TPA was measured with the instrument KaTid. All data were transformed to interval measures using applications of Rasch models and then further analysed with correlation and regression analysis. The results demonstrate a moderate significant relation between the parents' ratings of daily time management and TPA of the children, and between the self-rating of autonomy and TPA. There was also a significant relation between self-ratings of autonomy and the parents' rating of the children's daily time management. Parents' ratings of their children's daily time management explain 25% of the variation in TPA, age of the children explains 22%, while the child's self-rating of autonomy can explain 9% of the variation in TPA. The three variables together explain 38% of the variation in TPA. The results indicate the viability of the instrument for assessing TPA also in children with disabilities and that the ability measured by KaTid is relevant for daily time management. TPA seems to be a factor for children's daily time management that needs to be taken into consideration when planning and evaluating interventions designed to facilitate everyday functioning for children with

Socioeconomic inequalities in mortality and repeated measurement of explanatory risk factors in a 25 years follow-up.

PubMed

Skalická, Věra; Ringdal, Kristen; Witvliet, Margot I

2015-01-01

Socioeconomic inequalities in mortality can be explained by different groups of risk factors. However, little is known whether repeated measurement of risk factors can provide better explanation of socioeconomic inequalities in health. Our study examines the extent to which relative educational and income inequalities in mortality might be explained by explanatory risk factors (behavioral, psychosocial, biomedical risk factors and employment) measured at two points in time, as compared to one measurement at baseline. From the Norwegian total county population-based HUNT Study (years 1984-86 and 1995-1997, respectively) 61 513 men and women aged 25-80 (82.5% of all enrolled) were followed-up for mortality in 25 years until 2009, employing a discrete time survival analysis. Socioeconomic inequalities in mortality were observed. As compared to their highest socioeconomic counterparts, the lowest educated men had an OR (odds ratio) of 1.41 (95% CI 1.29-1.55) and for the lowest income quartile OR = 1.59 (1.48-1.571), for women OR = 1.35 (1.17-1.55), and OR = 1.40 (1.28-1.52), respectively. Baseline explanatory variables attenuated the association between education and income with mortality by 54% and 54% in men, respectively, and by 69% and 18% in women. After entering time-varying variables, this attainment increased to 63% and 59% in men, respectively, and to 25% (income) in women, with no improvement in regard to education in women. Change in biomedical factors and employment did not amend the explanation. Addition of a second measurement for risk factors provided only a modest improvement in explaining educational and income inequalities in mortality in Norwegian men and women. Accounting for change in behavior provided the largest improvement in explained inequalities in mortality for both men and women, as compared to measurement at baseline. Psychosocial factors explained the largest share of income inequalities in mortality for men, but repeated measurement of

Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion

PubMed Central

Emlen, Douglas J.; Pearson, Dean E.

2016-01-01

Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders’ web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe’s architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations. PMID:27082240

Common environmental factors explain both ectomycorrhizal species diversity and pine regeneration variability in a post-fire Mediterranean forest.

PubMed

Buscardo, Erika; Freitas, Helena; Pereira, João Santos; De Angelis, Paolo

2011-08-01

Natural seedling regeneration and establishment after stand replacing wildfires is influenced by a series of environmental and biological constraints. In this study, we characterized the diversity and structure of the ectomycorrhizal (ECM) fungal community associated with post-fire naturally regenerated maritime pine saplings, and individuate the environmental factors responsible for fungal species distribution. We also identify the main environmental factors responsible for maritime pine regeneration variability and assessed the relation between saplings performance and ECM fungal diversity indices. Fungal species were identified by direct sequencing of internal transcribed spacer regions. Five years after the disturbance event, a total of 30 taxa colonized the pine saplings. The ECM fungal community was dominated by ruderal species of the genus Rhizopogon (present in almost half of the samples). Almost one third of the identified ECM fungal species belonged to the family Thelephoraceae. Typical k-selected species like Amanita pantherina, Boletus aestivalis, Lactarius chrysorrheus, and Russula densifolia were found on pine saplings collected in proximity of unburnt pine trees, in correspondence with low erosion extents. Pine regeneration varied throughout the study areas and was enhanced at higher elevations, in correspondence with moderate slopes, shallower soils, and a reduced cover of ericaceous shrubs and bare ground. These conditions were found in close proximity to patches of pine trees that survived the disturbance event and were previously characterized by a higher pre-fire pine biomass. Even though no correlations were found between saplings performance and ECM fungal diversity indices, common environmental factors (i.e., ericaceous shrub cover, extent of erosion, slope, and soil depth) were responsible for shaping the ECM fungal distribution and for describing most of the explained regeneration variability.

Explaining the harmonic sequence paradox.

PubMed

Schmidt, Ulrich; Zimper, Alexander

2012-05-01

According to the harmonic sequence paradox, an expected utility decision maker's willingness to pay for a gamble whose expected payoffs evolve according to the harmonic series is finite if and only if his marginal utility of additional income becomes zero for rather low payoff levels. Since the assumption of zero marginal utility is implausible for finite payoff levels, expected utility theory - as well as its standard generalizations such as cumulative prospect theory - are apparently unable to explain a finite willingness to pay. This paper presents first an experimental study of the harmonic sequence paradox. Additionally, it demonstrates that the theoretical argument of the harmonic sequence paradox only applies to time-patient decision makers, whereas the paradox is easily avoided if time-impatience is introduced. ©2011 The British Psychological Society.

Does Social Capital Explain Community-Level Differences in Organ Donor Designation?

PubMed

Ladin, Keren; Wang, Rui; Fleishman, Aaron; Boger, Matthew; Rodrigue, James R

2015-09-01

The growing shortage of life-saving organs has reached unprecedented levels, with more than 120,000 Americans waiting for them. Despite national attempts to increase organ donation and federal laws mandating the equitable allocation of organs, geographic disparities remain. A better understanding of the contextual determinants of organ donor designation, including social capital, may enhance efforts to increase organ donation by raising the probability of collective action and fostering norms of reciprocity and cooperation while increasing costs to defectors. Because community-level factors, including social capital, predict more than half the variation in donor designation, future interventions should tailor strategies to specific communities as the unit of intervention. The growing shortage of organs has reached unprecedented levels. Despite national attempts to increase donation and federal laws mandating the equitable allocation of organs, their availability and waiting times vary significantly nationwide. Organ donor designation is a collective action problem in public health, in which the regional organ supply and average waiting times are determined by the willingness of individuals to be listed as organ donors. Social capital increases the probability of collective action by fostering norms of reciprocity and cooperation while increasing costs to defectors. We examine whether social capital and other community-level factors explain geographic variation in organ donor designation rates in Massachusetts. We obtained a sample of 3,281,532 registered drivers in 2010 from the Massachusetts Department of Transportation Registry of Motor Vehicles (MassDOT RMV). We then geocoded the registry data, matched them to 4,466 census blocks, and linked them to the 2010 US Census, the American Community Survey (ACS), and other sources to obtain community-level sociodemographic, social capital (residential segregation, voter registration and participation, residential

Comparison of the behavior of normal factor IX and the factor IX Bm variant Hilo in the prothrombin time test using tissue factors from bovine, human, and rabbit sources.

PubMed

Lefkowitz, J B; Monroe, D M; Kasper, C K; Roberts, H R

1993-07-01

A subset of hemophilia B patients have a prolonged bovine-brain prothrombin time. These CRM+ patients are classified as having hemophilia Bm. The prolongation of the prothrombin time has been reported only with bovine brain (referred to as ox brain in some literature) as the source of thromboplastin; prothrombin times determined with thromboplastin from rabbit brain or human brain are not reported to be prolonged. Factor IX from a hemophilia Bm patient (factor IX Hilo) was isolated. The activity of factor IX Hilo was compared to that of normal factor IX in prothrombin time assays when the thromboplastin source was of bovine, rabbit, or human origin. Factor IX, either normal or Hilo, prolonged a prothrombin time regardless of the tissue factor source. However, unless thromboplastin was from a bovine source, this prolongation required high concentrations of factor IX. Further, factor IX normal was as effective as factor IX Hilo in prolonging the prothrombin time when rabbit or human thromboplastin was used. With bovine thromboplastin, factor IX Hilo was significantly better than factor IX normal at prolonging the prothrombin time. The amount of prolongation was dependent on the amount of factor IX Hilo added. In addition, the prolongation was dependent on the concentration of factor X present in the sample. The prothrombin time changed as much as 20 seconds when the factor X concentration was varied from 50% to 150% to normal (fixed concentration of factor IX Hilo). These results demonstrate the difficulty of classifying the severity of a hemophilia Bm patient based on the bovine brain prothrombin time unless both the factor IX and factor X concentrations are known.

Weaker dental enamel explains dental decay.

PubMed

Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

2015-01-01

Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

Variation in fistula use across dialysis facilities: is it explained by case-mix?

PubMed

Tangri, Navdeep; Moorthi, Ranjani; Tighiouhart, Hocine; Meyer, Klemens B; Miskulin, Dana C

2010-02-01

Arteriovenous fistulas (AVFs) remain the preferred vascular access for hemodialysis patients. Dialysis facilities that fail to meet Centers for Medicare & Medicaid Services goals cite patient case-mix as a reason for low AVF prevalence. This study aimed to determine the magnitude of the variability in AVF usage across dialysis facilities and the extent to which patient case-mix explains it. The vascular access used in 10,112 patients dialyzed at 173 Dialysis Clinic Inc. facilities from October 1 to December 31, 2004, was evaluated. The access in use was considered to be an AVF if it was used for >70% of hemodialysis treatments. Mixed-effects models with a random intercept for dialysis facilities evaluated the effect of facilities on AVF usage. Sequentially adjusted multivariate models measured the extent to which patient factors (case-mix) explain variation across facilities in AVF rates. 3787 patients (38%) were dialyzed using AVFs. There was a significant facility effect: 7.6% of variation in AVF use was attributable to facility. This was reduced to 7.1% after case-mix adjustment. There were no identified specific facility-level factors that explained the interfacility variation. AVF usage varies across dialysis facilities, and patient case-mix did not reduce this variation. In this study, 92% of the total variation in AVF usage was due to patient factors, but most were not measurable. A combination of patient factors and process indicators should be considered in adjudicating facility performance for this quality indicator.

Time Course of Risk Factors in Cancer Etiology and Progression

PubMed Central

Wei, Esther K.; Wolin, Kathleen Y.; Colditz, Graham A.

2010-01-01

Patients with cancer increasingly ask what they can do to change their lifestyles and improve outcomes. Risk factors for onset of cancer may differ substantially from those that modify survival with implications for counseling. This review focuses on recent data derived from population-based studies of causes of cancer and of patients with cancer to contrast risk factors for etiology with those that impact survival. For different cancer sites, the level of information to inform the timing of lifestyle exposures and risk of disease onset or progression after diagnosis is often limited. For breast cancer, timing of some exposures, such as radiation, is particularly important. For other exposures, such as physical activity, higher levels may prevent onset and also improve survival. For colon cancer, study of precursor polyps has provided additional insight to timing. Extensive data indicate that physical activity reduces risk of colon cancer, and more limited data suggest that exposure after diagnosis improves survival. Dietary factors including folate and calcium may also reduce risk of onset. More limited data on prostate cancer point to obesity increasing risk of aggressive or advanced disease. Timing of change in lifestyle for change in risk of onset and for survival is important but understudied among patients with cancer. Counseling patients with cancer to increase physical activity and avoid weight gain may improve outcomes. Advice to family members on lifestyle may become increasingly important for breast and other cancers where family history is a strong risk factor. PMID:20644083

Explaining gender differences in ill-health in South Korea: the roles of socio-structural, psychosocial, and behavioral factors.

PubMed

Chun, Heeran; Khang, Young-Ho; Kim, Il-Ho; Cho, Sung-Il

2008-09-01

This study examines and explains the gender disparity in health despite rapid modernization in South Korea where the social structure is still based on traditional gender relations. A nationally representative sample of 2897 men and 3286 women aged 25-64 from the 2001 Korean National Health and Nutrition Examination Survey was analyzed. Health indicators included self rated health and chronic disease. Age-adjusted prevalence was computed according to a gender and odds ratios (OR) derived from logistic regression. Percentage changes in OR by inclusion of determinant variables (socio-structural, psychosocial, and behavioral) into the base logistic regression model were used to estimate the contributions to the gender gap in two morbidity measures. Results showed a substantial female excess in ill-health in both measures, revealing an increasing disparity in the older age group. Group-specific age-adjusted prevalence of ill-health showed an inverse relationship to socioeconomic position. When adjusting for each determinant, employment status, education, and depression contributed the greatest to the gender gap. After adjusting for all suggested determinants, 78% for self rated health and 86% for chronic disease in excess OR could be explained. After stratifying for age, the full model provided a complete explanation for the female excess in chronic illness, but for self rated health a female excess was still evident for the younger age group. Socio-structural factors played a crucial role in accounting for female excess in ill-health. This result calls for greater attention to gender-based health inequality stemming from socio-structural determinants in South Korea. Cross-cultural validation studies are suggested for further discussion of the link between changing gender relations and the gender health gap in morbidity in diverse settings.

Publication times, impact factors, and advance online publication in ophthalmology journals.

PubMed

Chen, Haoyu; Chen, Chun Hui; Jhanji, Vishal

2013-08-01

Publication speed of peer-reviewed journals may play a major role in early dissemination of knowledge and may raise the citation index. In this study, we evaluated the publication speed of ophthalmology journals. Observational study. Observational study of bibliometric data in published ophthalmology journals. A list of ophthalmic journals featured in the 2010 Journal Citation Report was obtained on September 1, 2011. A total of 12 articles were chosen randomly from each of these journals published between January and December 2010. Median publication time and interquartile range (IQR) were obtained from the full texts of the published articles. Time lag between submission and revision, acceptance, and publication of the manuscripts was calculated. Correlation between publication time lag and journal impact factor as well as advance online publication was analyzed. A total of 51 ophthalmic journals were included. There was no statistically significant difference in the impact factors of journals based on their reporting of submission, revision, or acceptance times of the manuscripts (both P>0.05, Wilcoxon test). The median peer review and publication time of all ophthalmology journals was 133 days (IQR, 100.5-171.5) and 100 days (IQR, 62.9-166.3), respectively. There was no correlation between the journal impact factors and publication time lag (Spearman correlation). Approximately half of the ophthalmology journals (n = 26; 50.98%) published online in advance. Journals with advance online publication had higher impact factors compared with those without this feature (median, 1.692 [IQR, 1.05-2.80] vs. 1.02 [0.39-1.53]; P = 0.015, Mann-Whitney U test). For journals with advance online publication, the median time from acceptance to advance online publication (74.3 days [IQR, 48.3-115 days]) was significantly shorter than the median time between acceptance and print publication (170.75 days [IQR, 101.4-217 days]; P<0.001, Wilcoxon test). Publication time lag in

Fatal attraction: Explaining Russia's sensitive nuclear transfers to Iran

NASA Astrophysics Data System (ADS)

Kuchinsky, Leah R.

This paper explores Russia's sensitive nuclear assistance to Iran in an effort to determine why a supplier state might proliferate against its own apparent security interests. The goal is to help readers understand the supply-side dynamics of nuclear proliferation. Through careful reconstruction of the historical narrative, using open source data, this study tests the plausibility of a "fatalistic calculus" explanation, identified by Stephen Sestanovich as a possible driver for Russia's behavior. According to the hypothesis, Russia has cooperated with Iran as a way both to stay in the good graces of a neighbor that is suspected of developing nuclear weapons and to win short-term influence and profits. The paper also examines the role of other factors advanced in the existing supply-side literature, such as economic motives identified by physicist and nonproliferation scholar David Albright. The findings show that bureaucratic, economic and fatalistic factors have each played a role in motivating Russia's cooperation with Iran, with their relative importance shifting over time. Fatalism begets a strategy of Russian "minimaxing," in the lexicon of Russia scholar Robert Freedman, wherein Russia attempts to minimize damage to its relationship with the U.S. while maximizing influence in Iran via nuclear cooperation. Fatalism, as actualized by minimaxing, best explains Russia's behavior after former Russian president Vladmir Putin came to power, when the bureaucratic and economic arguments become less cogent.

Characteristics explaining performance in downhill mountain biking.

PubMed

Chidley, Joel B; MacGregor, Alexandra L; Martin, Caoimhe; Arthur, Calum A; Macdonald, Jamie H

2015-03-01

To identify physiological, psychological, and skill characteristics that explain performance in downhill (DH) mountain-bike racing. Four studies were used to (1) identify factors potentially contributing to DH performance (using an expert focus group), (2) develop and validate a measure of rider skill (using video analysis and expert judge evaluation), (3) evaluate whether physiological, psychological, and skill variables contribute to performance at a DH competition, and (4) test the specific contribution of aerobic capacity to DH performance. STUDY 1 identified aerobic capacity, handgrip endurance, anaerobic power, rider skill, and self-confidence as potentially important for DH. In study 2 the rider-skill measure displayed good interrater reliability. Study 3 found that rider skill and handgrip endurance were significantly related to DH ride time (β=-0.76 and -0.14, respectively; R2=.73), with exploratory analyses suggesting that DH ride time may also be influenced by self-confidence and aerobic capacity. Study 4 confirmed aerobic capacity as an important variable influencing DH performance (for a DH ride, mean oxygen uptake was 49±5 mL·kg(-1)·min(-1), and 90% of the ride was completed above the 1st ventilatory threshold). In order of importance, rider skill, handgrip endurance, self-confidence, and aerobic capacity were identified as variables influencing DH performance. Practically, this study provides a novel assessment of rider skill that could be used by coaches to monitor training and identify talent. Novel intervention targets to enhance DH performance were also identified, including self-confidence and aerobic capacity.

Do Differences in School's Instruction Time Explain International Achievement Gaps in Math, Science, and Reading? Evidence from Developed and Developing Countries. NBER Working Paper No. 16227

ERIC Educational Resources Information Center

Lavy, Victor

2010-01-01

There are large differences across countries in instructional time in schooling institutions. Can these differences explain some of the differences across countries in pupils' achievements in different subjects? While research in recent years provides convincing evidence about the effect of several inputs in the education production function,…

How Do Social Factors Explain Outcomes in Non–Small-Cell Lung Cancer Among Hispanics in California? Explaining the Hispanic Paradox

PubMed Central

Patel, Manali I.; Schupp, Clayton W.; Gomez, Scarlett L.; Chang, Ellen T.; Wakelee, Heather A.

2013-01-01

Purpose Hispanics in the United States have lower age-adjusted mortality resulting from non–small-cell lung cancer (NSCLC) compared with non-Hispanic whites (NHWs). The purpose of this study was to evaluate individual, clinical, and neighborhood factors in survival among Hispanics with NSCLC. Patients and Methods We performed a retrospective analysis of NHWs and Hispanics with NSCLC between 1998 and 2007 in the California Cancer Registry (follow-up to December 2009). Kaplan-Meier curves depict survival by nativity for Hispanics with NSCLC. Cox proportional hazards models estimated hazard of mortality by race with adjustment for individual (age, sex, marital status), clinical (histologic grade, surgery, irradiation, chemotherapy), and neighborhood factors (neighborhood socioeconomic status, ethnic enclave). Results We included 14,280 Hispanic patients with NSCLC. Foreign-born Hispanics had 15% decreased risk of disease-specific mortality resulting from NSCLC compared with NHWs (hazard ratio [HR], 0.85; 95% CI, 0.83 to 0.88) after adjustment for individual, clinical, and neighborhood factors. After adjustment for individual factors, compared with US-born Hispanics, foreign-born Hispanics had 10% decreased risk of disease-specific mortality (HR, 0.90; 95% CI, 0.87 to 0.96). Clinical and neighborhood factors slightly moderated the survival benefit for foreign-born patients. A modestly more pronounced survival advantage was seen for foreign-born Hispanics living in low socioeconomic and high Hispanic enclave neighborhoods as compared with US-born Hispanics (HR, 0.86; 95% CI, 0.81 to 0.90). Conclusion Foreign-born Hispanics with NSCLC have a decreased risk of disease-specific mortality compared with NHWs and US-born Hispanics with NSCLC. Neighborhood factors slightly moderate this survival advantage. This survival advantage is slightly more pronounced in lower socioeconomic and higher Hispanic enclave neighborhoods. PMID:23960183

Explaining Career Decision-Making Self-Efficacy: Personality, Cognitions, and Cultural Mistrust

ERIC Educational Resources Information Center

Bullock-Yowell, Emily; Andrews, Lindsay; Buzzetta, Mary E.

2011-01-01

The authors explore the hypothesis that career decision-making self-efficacy could be affected by negative career thoughts, Big Five personality factors, and cultural mistrust in a sample of African American and Caucasian college students. Findings demonstrated that negative career thinking, openness, and conscientiousness explained a significant…

Reduced methane growth rate explained by decreased Northern Hemisphere microbial sources.

PubMed

Kai, Fuu Ming; Tyler, Stanley C; Randerson, James T; Blake, Donald R

2011-08-10

Atmospheric methane (CH(4)) increased through much of the twentieth century, but this trend gradually weakened until a stable state was temporarily reached around the turn of the millennium, after which levels increased once more. The reasons for the slowdown are incompletely understood, with past work identifying changes in fossil fuel, wetland and agricultural sources and hydroxyl (OH) sinks as important causal factors. Here we show that the late-twentieth-century changes in the CH(4) growth rates are best explained by reduced microbial sources in the Northern Hemisphere. Our results, based on synchronous time series of atmospheric CH(4) mixing and (13)C/(12)C ratios and a two-box atmospheric model, indicate that the evolution of the mixing ratio requires no significant change in Southern Hemisphere sources between 1984 and 2005. Observed changes in the interhemispheric difference of (13)C effectively exclude reduced fossil fuel emissions as the primary cause of the slowdown. The (13)C observations are consistent with long-term reductions in agricultural emissions or another microbial source within the Northern Hemisphere. Approximately half (51 ± 18%) of the decrease in Northern Hemisphere CH(4) emissions can be explained by reduced emissions from rice agriculture in Asia over the past three decades associated with increases in fertilizer application and reductions in water use.

Mapping information exposure on social media to explain differences in HPV vaccine coverage in the United States.

PubMed

Dunn, Adam G; Surian, Didi; Leask, Julie; Dey, Aditi; Mandl, Kenneth D; Coiera, Enrico

2017-05-25

Together with access, acceptance of vaccines affects human papillomavirus (HPV) vaccine coverage, yet little is known about media's role. Our aim was to determine whether measures of information exposure derived from Twitter could be used to explain differences in coverage in the United States. We conducted an analysis of exposure to information about HPV vaccines on Twitter, derived from 273.8 million exposures to 258,418 tweets posted between 1 October 2013 and 30 October 2015. Tweets were classified by topic using machine learning methods. Proportional exposure to each topic was used to construct multivariable models for predicting state-level HPV vaccine coverage, and compared to multivariable models constructed using socioeconomic factors: poverty, education, and insurance. Outcome measures included correlations between coverage and the individual topics and socioeconomic factors; and differences in the predictive performance of the multivariable models. Topics corresponding to media controversies were most closely correlated with coverage (both positively and negatively); education and insurance were highest among socioeconomic indicators. Measures of information exposure explained 68% of the variance in one dose 2015 HPV vaccine coverage in females (males: 63%). In comparison, models based on socioeconomic factors explained 42% of the variance in females (males: 40%). Measures of information exposure derived from Twitter explained differences in coverage that were not explained by socioeconomic factors. Vaccine coverage was lower in states where safety concerns, misinformation, and conspiracies made up higher proportions of exposures, suggesting that negative representations of vaccines in the media may reflect or influence vaccine acceptance. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Weaker Dental Enamel Explains Dental Decay

PubMed Central

Vieira, Alexandre R.; Gibson, Carolyn W.; Deeley, Kathleen; Xue, Hui; Li, Yong

2015-01-01

Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is “weaker” while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution. PMID:25885796

Socioeconomic Inequalities in Mortality and Repeated Measurement of Explanatory Risk Factors in a 25 Years Follow-Up

PubMed Central

Skalická, Věra; Ringdal, Kristen; Witvliet, Margot I.

2015-01-01

Background Socioeconomic inequalities in mortality can be explained by different groups of risk factors. However, little is known whether repeated measurement of risk factors can provide better explanation of socioeconomic inequalities in health. Our study examines the extent to which relative educational and income inequalities in mortality might be explained by explanatory risk factors (behavioral, psychosocial, biomedical risk factors and employment) measured at two points in time, as compared to one measurement at baseline. Methods and Findings From the Norwegian total county population-based HUNT Study (years 1984–86 and 1995–1997, respectively) 61 513 men and women aged 25–80 (82.5% of all enrolled) were followed-up for mortality in 25 years until 2009, employing a discrete time survival analysis. Socioeconomic inequalities in mortality were observed. As compared to their highest socioeconomic counterparts, the lowest educated men had an OR (odds ratio) of 1.41 (95% CI 1.29–1.55) and for the lowest income quartile OR = 1.59 (1.48–1.571), for women OR = 1.35 (1.17–1.55), and OR = 1.40 (1.28–1.52), respectively. Baseline explanatory variables attenuated the association between education and income with mortality by 54% and 54% in men, respectively, and by 69% and 18% in women. After entering time-varying variables, this attainment increased to 63% and 59% in men, respectively, and to 25% (income) in women, with no improvement in regard to education in women. Change in biomedical factors and employment did not amend the explanation. Conclusions Addition of a second measurement for risk factors provided only a modest improvement in explaining educational and income inequalities in mortality in Norwegian men and women. Accounting for change in behavior provided the largest improvement in explained inequalities in mortality for both men and women, as compared to measurement at baseline. Psychosocial factors explained the largest share of income

Explaining compound generalization in associative and causal learning through rational principles of dimensional generalization.

PubMed

Soto, Fabian A; Gershman, Samuel J; Niv, Yael

2014-07-01

How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here, we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed long-standing problems for rational theories of associative and causal learning. (c) 2014 APA, all rights reserved.

Explaining Compound Generalization in Associative and Causal Learning Through Rational Principles of Dimensional Generalization

PubMed Central

Soto, Fabian A.; Gershman, Samuel J.; Niv, Yael

2014-01-01

How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed longstanding problems for rational theories of associative and causal learning. PMID:25090430

Prevalence of excessive screen time and associated factors in adolescents

PubMed Central

de Lucena, Joana Marcela Sales; Cheng, Luanna Alexandra; Cavalcante, Thaísa Leite Mafaldo; da Silva, Vanessa Araújo; de Farias, José Cazuza

2015-01-01

Objective: To determine the prevalence of excessive screen time and to analyze associated factors among adolescents. Methods: This was a cross-sectional school-based epidemiological study with 2874 high school adolescents with age 14-19 years (57.8% female) from public and private schools in the city of João Pessoa, PB, Northeast Brazil. Excessive screen time was defined as watching television and playing video games or using the computer for more than 2 h/day. The associated factors analyzed were: sociodemographic (gender, age, economic class, and skin color), physical activity and nutritional status of adolescents. Results: The prevalence of excessive screen time was 79.5% (95%CI 78.1-81.1) and it was higher in males (84.3%) compared to females (76.1%; p<0.001). In multivariate analysis, adolescent males, those aged 14-15 year old and the highest economic class had higher chances of exposure to excessive screen time. The level of physical activity and nutritional status of adolescents were not associated with excessive screen time. Conclusions: The prevalence of excessive screen time was high and varied according to sociodemographic characteristics of adolescents. It is necessary to develop interventions to reduce the excessive screen time among adolescents, particularly in subgroups with higher exposure. PMID:26298661

Television screen time, but not computer use and reading time, is associated with cardio-metabolic biomarkers in a multiethnic Asian population: a cross-sectional study.

PubMed

Nang, Ei Ei Khaing; Salim, Agus; Wu, Yi; Tai, E Shyong; Lee, Jeannette; Van Dam, Rob M

2013-05-30

Recent evidence shows that sedentary behaviour may be an independent risk factor for cardiovascular diseases, diabetes, cancers and all-cause mortality. However, results are not consistent and different types of sedentary behaviour might have different effects on health. Thus the aim of this study was to evaluate the association between television screen time, computer/reading time and cardio-metabolic biomarkers in a multiethnic urban Asian population. We also sought to understand the potential mediators of this association. The Singapore Prospective Study Program (2004-2007), was a cross-sectional population-based study in a multiethnic population in Singapore. We studied 3305 Singaporean adults of Chinese, Malay and Indian ethnicity who did not have pre-existing diseases and conditions that could affect their physical activity. Multiple linear regression analysis was used to assess the association of television screen time and computer/reading time with cardio-metabolic biomarkers [blood pressure, lipids, glucose, adiponectin, C reactive protein and homeostasis model assessment of insulin resistance (HOMA-IR)]. Path analysis was used to examine the role of mediators of the observed association. Longer television screen time was significantly associated with higher systolic blood pressure, total cholesterol, triglycerides, C reactive protein, HOMA-IR, and lower adiponectin after adjustment for potential socio-demographic and lifestyle confounders. Dietary factors and body mass index, but not physical activity, were potential mediators that explained most of these associations between television screen time and cardio-metabolic biomarkers. The associations of television screen time with triglycerides and HOMA-IR were only partly explained by dietary factors and body mass index. No association was observed between computer/ reading time and worse levels of cardio-metabolic biomarkers. In this urban Asian population, television screen time was associated with worse

Factors that influence the timing of spontaneous labor at term.

PubMed

Fogleman, Kelly A; Herring, Amy H; Kaczor, Diane; Pusek, Susan N; Jo, Hyejin; Thorp, John M

2007-11-01

Whether pre-term birth culminates as a result of a de novo pathologic process or is more simply early activation of physiologic mechanisms is unknown. Exploration of the onset of labor in term women with classical risk factors for early delivery might provide insights into the mechanisms leading to pre-term birth. This study examines whether sociodemographic factors known to increase the risk of pre-term birth also affect the length of term gestations. From a large prospective cohort composed of women delivering from 1995-2000, a sample was selected of 441 women from Central North Carolina, US, who delivered singletons after 37 weeks gestation. An algorithm was designed to identify induced labors and gestational age was censored at the time of induction. Gestational age was assigned by sonography and menstrual dating. Data were analysed using the Cox proportional hazards model. The main outcome measure was time to spontaneous labor. Women with 12 years of education had longer periods of gestation than women with less than 12 years of education, HR = 0.57 [0.39, 0.84]. Shorter gestational periods were found for women with pre-term premature rupture of membranes (PPROM) in a previous pregnancy, HR = 3.70 [1.60, 8.52], even after adjusting for confounders. Smoking was not associated (p > 0.1) with the timing of labor at term. By studying the timing of spontaneous parturition at term we identified that there is little overlap in risk factors that affect timing of delivery between spontaneous term and pre-term births.

Blazar spectral variability as explained by a twisted inhomogeneous jet.

PubMed

Raiteri, C M; Villata, M; Acosta-Pulido, J A; Agudo, I; Arkharov, A A; Bachev, R; Baida, G V; Benítez, E; Borman, G A; Boschin, W; Bozhilov, V; Butuzova, M S; Calcidese, P; Carnerero, M I; Carosati, D; Casadio, C; Castro-Segura, N; Chen, W-P; Damljanovic, G; D'Ammando, F; Di Paola, A; Echevarría, J; Efimova, N V; Ehgamberdiev, Sh A; Espinosa, C; Fuentes, A; Giunta, A; Gómez, J L; Grishina, T S; Gurwell, M A; Hiriart, D; Jermak, H; Jordan, B; Jorstad, S G; Joshi, M; Kopatskaya, E N; Kuratov, K; Kurtanidze, O M; Kurtanidze, S O; Lähteenmäki, A; Larionov, V M; Larionova, E G; Larionova, L V; Lázaro, C; Lin, C S; Malmrose, M P; Marscher, A P; Matsumoto, K; McBreen, B; Michel, R; Mihov, B; Minev, M; Mirzaqulov, D O; Mokrushina, A A; Molina, S N; Moody, J W; Morozova, D A; Nazarov, S V; Nikolashvili, M G; Ohlert, J M; Okhmat, D N; Ovcharov, E; Pinna, F; Polakis, T A; Protasio, C; Pursimo, T; Redondo-Lorenzo, F J; Rizzi, N; Rodriguez-Coira, G; Sadakane, K; Sadun, A C; Samal, M R; Savchenko, S S; Semkov, E; Skiff, B A; Slavcheva-Mihova, L; Smith, P S; Steele, I A; Strigachev, A; Tammi, J; Thum, C; Tornikoski, M; Troitskaya, Yu V; Troitsky, I S; Vasilyev, A A; Vince, O

2017-12-21

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle

Blazar spectral variability as explained by a twisted inhomogeneous jet

NASA Astrophysics Data System (ADS)

Raiteri, C. M.; Villata, M.; Acosta-Pulido, J. A.; Agudo, I.; Arkharov, A. A.; Bachev, R.; Baida, G. V.; Benítez, E.; Borman, G. A.; Boschin, W.; Bozhilov, V.; Butuzova, M. S.; Calcidese, P.; Carnerero, M. I.; Carosati, D.; Casadio, C.; Castro-Segura, N.; Chen, W.-P.; Damljanovic, G.; D'Ammando, F.; di Paola, A.; Echevarría, J.; Efimova, N. V.; Ehgamberdiev, Sh. A.; Espinosa, C.; Fuentes, A.; Giunta, A.; Gómez, J. L.; Grishina, T. S.; Gurwell, M. A.; Hiriart, D.; Jermak, H.; Jordan, B.; Jorstad, S. G.; Joshi, M.; Kopatskaya, E. N.; Kuratov, K.; Kurtanidze, O. M.; Kurtanidze, S. O.; Lähteenmäki, A.; Larionov, V. M.; Larionova, E. G.; Larionova, L. V.; Lázaro, C.; Lin, C. S.; Malmrose, M. P.; Marscher, A. P.; Matsumoto, K.; McBreen, B.; Michel, R.; Mihov, B.; Minev, M.; Mirzaqulov, D. O.; Mokrushina, A. A.; Molina, S. N.; Moody, J. W.; Morozova, D. A.; Nazarov, S. V.; Nikolashvili, M. G.; Ohlert, J. M.; Okhmat, D. N.; Ovcharov, E.; Pinna, F.; Polakis, T. A.; Protasio, C.; Pursimo, T.; Redondo-Lorenzo, F. J.; Rizzi, N.; Rodriguez-Coira, G.; Sadakane, K.; Sadun, A. C.; Samal, M. R.; Savchenko, S. S.; Semkov, E.; Skiff, B. A.; Slavcheva-Mihova, L.; Smith, P. S.; Steele, I. A.; Strigachev, A.; Tammi, J.; Thum, C.; Tornikoski, M.; Troitskaya, Yu. V.; Troitsky, I. S.; Vasilyev, A. A.; Vince, O.

2017-12-01

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions—such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution—can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016–2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing

Cognitive factors affecting student understanding of geologic time

NASA Astrophysics Data System (ADS)

Dodick, Jeff; Orion, Nir

2003-04-01

A critical element of the earth sciences is reconstructing geological structures and systems that have developed over time. A survey of the science education literature shows that there has been little attention given to this concept. In this study, we present a model, based on Montagnero's ([1996]) model of diachronic thinking, which describes how students reconstruct geological transformations over time. For geology, three schemes of diachronic thinking are relevant: 1. Transformation, which is a principle of change; in geology it is understood through actualistic thinking (the idea that present proceeses can be used to model the past). 2. Temporal organization, which defines the sequential order of a transformation; in geology it is based on the three-dimensional relationship among strata. 3. Interstage linkage, which is the connections between successive stages of a transformation; in geology it is based on both actualism and causal reasoning. Three specialized instruments were designed to determine the factors which influence reconstructive thinking: (a) the GeoTAT which tests diachronic thinking skills, (b) the TST which tests the relationship between spatial thinking and temporal thinking, and (c) the SFT which tests the influence of dimensional factors on temporal awareness. Based on the model constructed in this study we define the critical factors influencing reconstructive thinking: (a) the transformation scheme which influences the other diachronic schemes, (b) knowledge of geological processes, and (c) extracognitive factors. Among the students tested, there was a significant difference between Grade 9-12 students and Grade 7-8 students in their ability to reconstruct geological phenomena using diachronic thinking. This suggests that somewhere between Grades 7 and 8 it is possible to start teaching some of the logical principles used in geology to reconstruct geological structures.

Competing risks models and time-dependent covariates

PubMed Central

Barnett, Adrian; Graves, Nick

2008-01-01

New statistical models for analysing survival data in an intensive care unit context have recently been developed. Two models that offer significant advantages over standard survival analyses are competing risks models and multistate models. Wolkewitz and colleagues used a competing risks model to examine survival times for nosocomial pneumonia and mortality. Their model was able to incorporate time-dependent covariates and so examine how risk factors that changed with time affected the chances of infection or death. We briefly explain how an alternative modelling technique (using logistic regression) can more fully exploit time-dependent covariates for this type of data. PMID:18423067

Conceptual Foundations of Systems Biology Explaining Complex Cardiac Diseases.

PubMed

Louridas, George E; Lourida, Katerina G

2017-02-21

Systems biology is an important concept that connects molecular biology and genomics with computing science, mathematics and engineering. An endeavor is made in this paper to associate basic conceptual ideas of systems biology with clinical medicine. Complex cardiac diseases are clinical phenotypes generated by integration of genetic, molecular and environmental factors. Basic concepts of systems biology like network construction, modular thinking, biological constraints (downward biological direction) and emergence (upward biological direction) could be applied to clinical medicine. Especially, in the field of cardiology, these concepts can be used to explain complex clinical cardiac phenotypes like chronic heart failure and coronary artery disease. Cardiac diseases are biological complex entities which like other biological phenomena can be explained by a systems biology approach. The above powerful biological tools of systems biology can explain robustness growth and stability during disease process from modulation to phenotype. The purpose of the present review paper is to implement systems biology strategy and incorporate some conceptual issues raised by this approach into the clinical field of complex cardiac diseases. Cardiac disease process and progression can be addressed by the holistic realistic approach of systems biology in order to define in better terms earlier diagnosis and more effective therapy.

A Study of Personality Traits to Explain Employees' Information Security Behavior among Generational Cohorts

ERIC Educational Resources Information Center

Warrington, Cartmell

2017-01-01

In this study, the Big Five factor model of personality traits theory was tested for its ability to predict or explain Employee Information Security Behavior (EISB), when Generational Cohort (GCOHORT) moderated the relationship between the five factors of personality and EISB. The independent variables (IVs) Extraversion, Agreeableness,…

[Prevalence of excessive screen time and associated factors in adolescents].

PubMed

de Lucena, Joana Marcela Sales; Cheng, Luanna Alexandra; Cavalcante, Thaísa Leite Mafaldo; da Silva, Vanessa Araújo; de Farias Júnior, José Cazuza

2015-12-01

To determine the prevalence of excessive screen time and to analyze associated factors among adolescents. This was a cross-sectional school-based epidemiological study with 2,874 high school adolescents with age 14-19 years (57.8% female) from public and private schools in the city of João Pessoa, PB, Northeast Brazil. Excessive screen time was defined as watching television and playing video games or using the computer for more than two hours per day. The associated factors analyzed were: sociodemographic (gender, age, economic class, and skin color), physical activity and nutritional status of adolescents. The prevalence of excessive screen time was 79.5% (95%CI: 78.1-81.1) and it was higher in males (84.3%) compared to females (76.1%; p<0,001). In multivariate analysis, adolescent males, aged 14-15 years old, of higher economic classes had higher chances of exposure to excessive screen time. The level of physical activity and nutritional status of adolescents were not associated with excessive screen time. The prevalence of excessive screen time was high and varied according to sociodemographic characteristics of adolescents. It is necessary to develop interventions to reduce the excessive screen time among adolescents, particularly in subgroups with higher exposure. Copyright © 2015 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

A human factors methodology for real-time support applications

NASA Technical Reports Server (NTRS)

Murphy, E. D.; Vanbalen, P. M.; Mitchell, C. M.

1983-01-01

A general approach to the human factors (HF) analysis of new or existing projects at NASA/Goddard is delineated. Because the methodology evolved from HF evaluations of the Mission Planning Terminal (MPT) and the Earth Radiation Budget Satellite Mission Operations Room (ERBS MOR), it is directed specifically to the HF analysis of real-time support applications. Major topics included for discussion are the process of establishing a working relationship between the Human Factors Group (HFG) and the project, orientation of HF analysts to the project, human factors analysis and review, and coordination with major cycles of system development. Sub-topics include specific areas for analysis and appropriate HF tools. Management support functions are outlined. References provide a guide to sources of further information.

Environmental and Genetic Factors Explain Differences in Intraocular Scattering.

PubMed

Benito, Antonio; Hervella, Lucía; Tabernero, Juan; Pennos, Alexandros; Ginis, Harilaos; Sánchez-Romera, Juan F; Ordoñana, Juan R; Ruiz-Sánchez, Marcos; Marín, José M; Artal, Pablo

2016-01-01

To study the relative impact of genetic and environmental factors on the variability of intraocular scattering within a classical twin study. A total of 64 twin pairs, 32 monozygotic (MZ) (mean age: 54.9 ± 6.3 years) and 32 dizygotic (DZ) (mean age: 56.4 ± 7.0 years), were measured after a complete ophthalmologic exam had been performed to exclude all ocular pathologies that increase intraocular scatter as cataracts. Intraocular scattering was evaluated by using two different techniques based on a straylight parameter log(S) estimation: a compact optical instrument based in the principle of optical integration and a psychophysical measurement. Intraclass correlation coefficients (ICC) were used as descriptive statistics of twin resemblance, and genetic models were fitted to estimate heritability. No statistically significant difference was found for MZ and DZ groups for age (P = 0.203), best-corrected visual acuity (P = 0.626), cataract gradation (P = 0.701), sex (P = 0.941), optical log(S) (P = 0.386), or psychophysical log(S) (P = 0.568), with only a minor difference in equivalent sphere (P = 0.008). Intraclass correlation coefficients between siblings were similar for scatter parameters: 0.676 in MZ and 0.471 in DZ twins for optical log(S); 0.533 in MZ twins and 0.475 in DZ twins for psychophysical log(S). For equivalent sphere, ICCs were 0.767 in MZ and 0.228 in DZ twins. Conservative estimates of heritability for the measured scattering parameters were 0.39 and 0.20, respectively. Correlations of intraocular scatter (straylight) parameters in the groups of identical and nonidentical twins were similar. Heritability estimates were of limited magnitude, suggesting that genetic and environmental factors determine the variance of ocular straylight in healthy middle-aged adults.

Timing resolution and time walk in super low K factor single-photon avalanche diode-measurement and optimization

NASA Astrophysics Data System (ADS)

Fong, Bernicy S.; Davies, Murray; Deschamps, Pierre

2018-01-01

Timing resolution (or timing jitter) and time walk are separate parameters associated with a detector's response time. Studies have been done mostly on the time resolution of various single-photon detectors. As the designer and manufacturer of the ultra-low noise (ƙ-factor) silicon avalanche photodiode the super low K factor (SLiK) single-photon avalanche diode (SPAD), which is used in many single-photon counting applications, we often get inquiries from customers to better understand how this detector behaves under different operating conditions. Hence, here, we will be focusing on the study of these time-related parameters specifically for the SLiK SPAD, as a way to provide the most direct information for users of this detector to help with its use more efficiently and effectively. We will be providing the study data on how these parameters can be affected by temperature (both intrinsic to the detector chip and environmental input based on operating conditions), operating voltage, photon wavelength, as well as light spot size. How these parameters can be optimized and the trade-offs from optimization from the desired performance will be presented?

Real-time correction of tsunami site effect by frequency-dependent tsunami-amplification factor

NASA Astrophysics Data System (ADS)

Tsushima, H.

2017-12-01

For tsunami early warning, I developed frequency-dependent tsunami-amplification factor and used it to design a recursive digital filter that can be applicable for real-time correction of tsunami site response. In this study, I assumed that a tsunami waveform at an observing point could be modeled by convolution of source, path and site effects in time domain. Under this assumption, spectral ratio between offshore and the nearby coast can be regarded as site response (i.e. frequency-dependent amplification factor). If the amplification factor can be prepared before tsunamigenic earthquakes, its temporal convolution to offshore tsunami waveform provides tsunami prediction at coast in real time. In this study, tsunami waveforms calculated by tsunami numerical simulations were used to develop frequency-dependent tsunami-amplification factor. Firstly, I performed numerical tsunami simulations based on nonlinear shallow-water theory from many tsuanmigenic earthquake scenarios by varying the seismic magnitudes and locations. The resultant tsunami waveforms at offshore and the nearby coastal observing points were then used in spectral-ratio analysis. An average of the resulted spectral ratios from the tsunamigenic-earthquake scenarios is regarded as frequency-dependent amplification factor. Finally, the estimated amplification factor is used in design of a recursive digital filter that can be applicable in time domain. The above procedure is applied to Miyako bay at the Pacific coast of northeastern Japan. The averaged tsunami-height spectral ratio (i.e. amplification factor) between the location at the center of the bay and the outside show a peak at wave-period of 20 min. A recursive digital filter based on the estimated amplification factor shows good performance in real-time correction of tsunami-height amplification due to the site effect. This study is supported by Japan Society for the Promotion of Science (JSPS) KAKENHI grant 15K16309.

Behavioural cues surpass habitat factors in explaining prebreeding resource selection by a migratory diving duck

USGS Publications Warehouse

O'Neil, Shawn T.; Warren, Jeffrey M.; Takekawa, John Y.; De La Cruz, Susan E. W.; Cutting, Kyle A.; Parker, Michael W.; Yee, Julie L.

2014-01-01

Prebreeding habitat selection in birds can often be explained in part by habitat characteristics. However, females may also select habitats on the basis of fidelity to areas of previous reproductive success or use by conspecifics. The relative influences of sociobehavioural attributes versus habitat characteristics in habitat selection has been primarily investigated in songbirds, while less is known about how these factors affect habitat selection processes in migratory waterfowl. Animal resource selection models often exhibit much unexplained variation; spatial patterns driven by social and behavioural characteristics may account for some of this. We radiomarked female lesser scaup, Aythya affinis, in the southwestern extent of their breeding range to explore hypotheses regarding relative roles of habitat quality, site fidelity and conspecific density in prebreeding habitat selection. We used linear mixed-effects models to relate intensity of use within female home ranges to habitat features, distance to areas of reproductive success during the previous breeding season and conspecific density. Home range habitats included shallow water (≤118 cm), moderate to high densities of flooded emergent vegetation/open water edge and open water areas with submerged aquatic vegetation. Compared with habitat features, conspecific female density and proximity to successful nesting habitats from the previous breeding season had greater influences on habitat use within home ranges. Fidelity and conspecific attraction are behavioural characteristics in some waterfowl species that may exert a greater influence than habitat features in influencing prebreeding space use and habitat selection within home ranges, particularly where quality habitat is abundant. These processes may be of critical importance to a better understanding of habitat selection in breeding birds.

Inactivity periods and postural change speed can explain atypical postural change patterns of Caenorhabditis elegans mutants.

PubMed

Fukunaga, Tsukasa; Iwasaki, Wataru

2017-01-19

With rapid advances in genome sequencing and editing technologies, systematic and quantitative analysis of animal behavior is expected to be another key to facilitating data-driven behavioral genetics. The nematode Caenorhabditis elegans is a model organism in this field. Several video-tracking systems are available for automatically recording behavioral data for the nematode, but computational methods for analyzing these data are still under development. In this study, we applied the Gaussian mixture model-based binning method to time-series postural data for 322 C. elegans strains. We revealed that the occurrence patterns of the postural states and the transition patterns among these states have a relationship as expected, and such a relationship must be taken into account to identify strains with atypical behaviors that are different from those of wild type. Based on this observation, we identified several strains that exhibit atypical transition patterns that cannot be fully explained by their occurrence patterns of postural states. Surprisingly, we found that two simple factors-overall acceleration of postural movement and elimination of inactivity periods-explained the behavioral characteristics of strains with very atypical transition patterns; therefore, computational analysis of animal behavior must be accompanied by evaluation of the effects of these simple factors. Finally, we found that the npr-1 and npr-3 mutants have similar behavioral patterns that were not predictable by sequence homology, proving that our data-driven approach can reveal the functions of genes that have not yet been characterized. We propose that elimination of inactivity periods and overall acceleration of postural change speed can explain behavioral phenotypes of strains with very atypical postural transition patterns. Our methods and results constitute guidelines for effectively finding strains that show "truly" interesting behaviors and systematically uncovering novel gene

Which factors predict the time spent answering queries to a drug information centre?

PubMed Central

Reppe, Linda A.; Spigset, Olav

2010-01-01

Objective To develop a model based upon factors able to predict the time spent answering drug-related queries to Norwegian drug information centres (DICs). Setting and method Drug-related queries received at 5 DICs in Norway from March to May 2007 were randomly assigned to 20 employees until each of them had answered a minimum of five queries. The employees reported the number of drugs involved, the type of literature search performed, and whether the queries were considered judgmental or not, using a specifically developed scoring system. Main outcome measures The scores of these three factors were added together to define a workload score for each query. Workload and its individual factors were subsequently related to the measured time spent answering the queries by simple or multiple linear regression analyses. Results Ninety-six query/answer pairs were analyzed. Workload significantly predicted the time spent answering the queries (adjusted R2 = 0.22, P < 0.001). Literature search was the individual factor best predicting the time spent answering the queries (adjusted R2 = 0.17, P < 0.001), and this variable also contributed the most in the multiple regression analyses. Conclusion The most important workload factor predicting the time spent handling the queries in this study was the type of literature search that had to be performed. The categorisation of queries as judgmental or not, also affected the time spent answering the queries. The number of drugs involved did not significantly influence the time spent answering drug information queries. PMID:20922480

Rotation in the Dynamic Factor Modeling of Multivariate Stationary Time Series.

ERIC Educational Resources Information Center

Molenaar, Peter C. M.; Nesselroade, John R.

2001-01-01

Proposes a special rotation procedure for the exploratory dynamic factor model for stationary multivariate time series. The rotation procedure applies separately to each univariate component series of a q-variate latent factor series and transforms such a component, initially represented as white noise, into a univariate moving-average.…

Principal Time Management Skills: Explaining Patterns in Principals' Time Use, Job Stress, and Perceived Effectiveness

ERIC Educational Resources Information Center

Grissom, Jason A.; Loeb, Susanna; Mitani, Hajime

2015-01-01

Purpose: Time demands faced by school principals make principals' work increasingly difficult. Research outside education suggests that effective time management skills may help principals meet job demands, reduce job stress, and improve their performance. The purpose of this paper is to investigate these hypotheses. Design/methodology/approach:…

Identifying environmental variables explaining genotype-by-environment interaction for body weight of rainbow trout (Onchorynchus mykiss): reaction norm and factor analytic models.

PubMed

Sae-Lim, Panya; Komen, Hans; Kause, Antti; Mulder, Han A

2014-02-26

Identifying the relevant environmental variables that cause GxE interaction is often difficult when they cannot be experimentally manipulated. Two statistical approaches can be applied to address this question. When data on candidate environmental variables are available, GxE interaction can be quantified as a function of specific environmental variables using a reaction norm model. Alternatively, a factor analytic model can be used to identify the latent common factor that explains GxE interaction. This factor can be correlated with known environmental variables to identify those that are relevant. Previously, we reported a significant GxE interaction for body weight at harvest in rainbow trout reared on three continents. Here we explore their possible causes. Reaction norm and factor analytic models were used to identify which environmental variables (age at harvest, water temperature, oxygen, and photoperiod) may have caused the observed GxE interaction. Data on body weight at harvest was recorded on 8976 offspring reared in various locations: (1) a breeding environment in the USA (nucleus), (2) a recirculating aquaculture system in the Freshwater Institute in West Virginia, USA, (3) a high-altitude farm in Peru, and (4) a low-water temperature farm in Germany. Akaike and Bayesian information criteria were used to compare models. The combination of days to harvest multiplied with daily temperature (Day*Degree) and photoperiod were identified by the reaction norm model as the environmental variables responsible for the GxE interaction. The latent common factor that was identified by the factor analytic model showed the highest correlation with Day*Degree. Day*Degree and photoperiod were the environmental variables that differed most between Peru and other environments. Akaike and Bayesian information criteria indicated that the factor analytical model was more parsimonious than the reaction norm model. Day*Degree and photoperiod were identified as environmental

Identifying environmental variables explaining genotype-by-environment interaction for body weight of rainbow trout (Onchorynchus mykiss): reaction norm and factor analytic models

PubMed Central

2014-01-01

Background Identifying the relevant environmental variables that cause GxE interaction is often difficult when they cannot be experimentally manipulated. Two statistical approaches can be applied to address this question. When data on candidate environmental variables are available, GxE interaction can be quantified as a function of specific environmental variables using a reaction norm model. Alternatively, a factor analytic model can be used to identify the latent common factor that explains GxE interaction. This factor can be correlated with known environmental variables to identify those that are relevant. Previously, we reported a significant GxE interaction for body weight at harvest in rainbow trout reared on three continents. Here we explore their possible causes. Methods Reaction norm and factor analytic models were used to identify which environmental variables (age at harvest, water temperature, oxygen, and photoperiod) may have caused the observed GxE interaction. Data on body weight at harvest was recorded on 8976 offspring reared in various locations: (1) a breeding environment in the USA (nucleus), (2) a recirculating aquaculture system in the Freshwater Institute in West Virginia, USA, (3) a high-altitude farm in Peru, and (4) a low-water temperature farm in Germany. Akaike and Bayesian information criteria were used to compare models. Results The combination of days to harvest multiplied with daily temperature (Day*Degree) and photoperiod were identified by the reaction norm model as the environmental variables responsible for the GxE interaction. The latent common factor that was identified by the factor analytic model showed the highest correlation with Day*Degree. Day*Degree and photoperiod were the environmental variables that differed most between Peru and other environments. Akaike and Bayesian information criteria indicated that the factor analytical model was more parsimonious than the reaction norm model. Conclusions Day*Degree and

Can theories of visual representation help to explain asymmetries in amygdala function?

PubMed

McMenamin, Brenton W; Marsolek, Chad J

2013-06-01

Emotional processing differs between the left and right hemispheres of the brain, and functional differences have been reported more specifically between the left and right amygdalae, subcortical structures heavily implicated in emotional processing. However, the empirical pattern of amygdalar asymmetries is inconsistent with extant theories of emotional asymmetries. Here we review this discrepancy, and we hypothesize that hemispheric differences in visual object processing help to explain the previously reported functional differences between the left and right amygdalae. The implication that perceptual factors play a large role in determining amygdalar asymmetries may help to explain amygdalar dysfunction in the development and maintenance of posttraumatic stress disorder.

Explaining the Colavita visual dominance effect.

PubMed

Spence, Charles

2009-01-01

The last couple of years have seen a resurgence of interest in the Colavita visual dominance effect. In the basic experimental paradigm, a random series of auditory, visual, and audiovisual stimuli are presented to participants who are instructed to make one response whenever they see a visual target and another response whenever they hear an auditory target. Many studies have now shown that participants sometimes fail to respond to auditory targets when they are presented at the same time as visual targets (i.e., on the bimodal trials), despite the fact that they have no problems in responding to the auditory and visual stimuli when they are presented individually. The existence of the Colavita visual dominance effect provides an intriguing contrast with the results of the many other recent studies showing the superiority of multisensory (over unisensory) information processing in humans. Various accounts have been put forward over the years in order to try and explain the effect, including the suggestion that it reflects nothing more than an underlying bias to attend to the visual modality. Here, the empirical literature on the Colavita visual dominance effect is reviewed and some of the key factors modulating the effect highlighted. The available research has now provided evidence against all previous accounts of the Colavita effect. A novel explanation of the Colavita effect is therefore put forward here, one that is based on the latest findings highlighting the asymmetrical effect that auditory and visual stimuli exert on people's responses to stimuli presented in the other modality.

A Drought-Inducible Transcription Factor Delays Reproductive Timing in Rice.

PubMed

Zhang, Chunyu; Liu, Jun; Zhao, Tao; Gomez, Adam; Li, Cong; Yu, Chunsheng; Li, Hongyu; Lin, Jianzhong; Yang, Yuanzhu; Liu, Bin; Lin, Chentao

2016-05-01

The molecular mechanisms underlying photoperiod or temperature control of flowering time have been recently elucidated, but how plants regulate flowering time in response to other external factors, such as water availability, remains poorly understood. Using a large-scale Hybrid Transcription Factor approach, we identified a bZIP transcriptional factor, O. sativa ABA responsive element binding factor 1 (OsABF1), which acts as a suppressor of floral transition in a photoperiod-independent manner. Simultaneous knockdown of both OsABF1 and its closest homologous gene, OsbZIP40, in rice (Oryza sativa) by RNA interference results in a significantly earlier flowering phenotype. Molecular and genetic analyses demonstrate that a drought regime enhances expression of the OsABF1 gene, which indirectly suppresses expression of the Early heading date 1 (Ehd1) gene that encodes a key activator of rice flowering. Furthermore, we identified a drought-inducible gene named OsWRKY104 that is under the direct regulation of OsABF1 Overexpression of OsWRKY104 can suppress Ehd1 expression and confers a later flowering phenotype in rice. Together, these findings reveal a novel pathway by which rice modulates heading date in response to the change of ambient water availability. © 2016 American Society of Plant Biologists. All Rights Reserved.

DIFFERENCES IN IMMUNE RESPONSE MAY EXPLAIN LOWER SURVIVAL AMONG OLDER MEN WITH PNEUMONIA

PubMed Central

Reade, Michael C.; Yende, Sachin; D’Angelo, Gina; Kong, Lan; Kellum, John A; Barnato, Amber E.; Milbrandt, Eric B.; Dooley, Christopher; Mayr, Florian B.; Weissfeld, Lisa; Angus, Derek C.

2009-01-01

Objective Lower life expectancy in men is generally attributed to higher likelihood of risky behavior and because men develop chronic conditions earlier. If sex-related differences in survival are independent of pre-infection chronic health and health behavior, it would suggest that survival differences may occur due to sex differences in quality of care and biologic response to infection and these differences may contribute to sex differences in life expectancy. We assessed if sex-related survival difference following community-acquired pneumonia (CAP) is due to differences in clinical characteristics, quality of care, or immune response. Design, setting, and subjects Prospective observational cohort of 2183 subjects with CAP. Measurements and main results Mean age was 64.9 years. Compared to women, men were more likely to smoke and had more comorbidity. At emergency department presentation, men had different biomarker patterns, as evidenced by higher inflammation (tumor necrosis factor (TNF), interleukin (IL)-6, and IL-10) and fibrinolysis (D-dimer), and lower coagulation biomarkers (antithrombin-III and Factor IX) (P<0.05). Small differences in favor of men were seen in care quality, including antibiotic timing and compliance with American Thoracic Society guidelines. Men had lower survival at 30, 90, 365 days. The higher one-year mortality was not attenuated when adjusted for differences in demographics, smoking, resuscitation, insurance, and vaccination status, comorbidity, hospital characteristics, and illness severity (unadjusted hazard ratio (HR)=1.35, p=0.003 and adjusted HR=1.29, p=0.004). HR were no longer statistically significant when additionally adjusted for differences in ED concentrations of TNF, IL-6, IL-10, D-dimer, antithrombin-III, and Factor IX (adjusted HR=1.27, p=0.17). Patterns of biomarkers observed in men were associated with worse survival over one year. Conclusions Lower survival among men following CAP was not explained by differences

What factors influence time-use of occupational therapists in the workplace? A systematic review.

PubMed

Summers, Bianca E; Laver, Kate E; Nicks, Rebecca J; Lannin, Natasha A

2018-06-01

Health-care expenditure is rapidly increasing in Australia with increasing pressure on health-care services to review processes, improve efficiency and ensure equity in service delivery. The nursing profession have improved efficiency and patient care by investigating time-use to describe current practice and support development of workforce planning models. There is, however, a lack of information to understand factors that impact on occupational therapists time-use in the clinical setting impacting the development of workforce planning models which adapt occupational therapy service delivery to match resources with demand. The objective of this review was to systematically identify known factors which impact on occupational therapists time-use in the clinical setting. A systematic review of Medline, PsycINFO and CINAHL databases and grey literature was completed in September 2016. Two authors independently screened studies for inclusion and quality was evaluated using the Downs and Black scale. Variables impacting on occupational therapists time-use were categorised and thematically analysed to synthesise key themes. Twenty studies met the inclusion criteria and were included in the review. Three key categories of factors influencing time-use were identified. These were: patient-related factors (e.g. level of function, therapy required, type, complexity of injury), therapist-related factors (e.g. experience, clinical vs non-clinical responsibility), and organisational-related factors (e.g. workplace characteristics, availability of staff, presence of students). Occupational therapist time-use in clinical settings is complex and difficult to quantify in research. How occupational therapists spend their time is impacted by a number of patient, clinician and service related factors reflecting the breadth of occupational therapy practice and client-centred nature of the profession. © 2018 Occupational Therapy Australia.

Factors Influencing Time-to-diagnosis of Biliary Atresia.

PubMed

Harpavat, Sanjiv; Lupo, Philip J; Liwanag, Loriel; Hollier, John; Brandt, Mary L; Finegold, Milton J; Shneider, Benjamin L

2018-06-01

Diagnosing biliary atresia (BA) quickly is critical, because earlier treatment correlates with delayed or reduced need for liver transplantation. However, diagnosing BA quickly is also difficult, with infants usually treated after 60 days of life. In this study, we aim to accelerate BA diagnosis and treatment, by better understanding factors influencing the diagnostic timeline. Infants born between 2007 and 2014 and diagnosed with BA at our institution were included (n = 65). Two periods were examined retrospectively: P1, the time from birth to specialist referral, and P2, the time from specialist referral to treatment. How sociodemographic factors associate with P1 and P2 were analyzed with Kaplan-Meier curves and Cox proportional hazard models. In addition, to better characterize P2, laboratory results and early tissue histology were studied. P1 associated with race/ethnicity, with shorter times in non-Hispanic white infants compared to non-Hispanic black and Hispanic infants (P = 0.007 and P = 0.004, respectively). P2 associated with referral age, with shorter times in infants referred after 30, 45, or 60 days of life (P < 0.001, P < 0.001, and P = 0.001, respectively). One potential reason for longer P2 in infants referred ≤30 days is that aminotransferase levels were normal or near-normal. However, despite reassuring laboratory values, tissue histology in early cases showed key features of BA. Our findings suggest 2 opportunities to accelerate BA diagnosis and treatment. First, to achieve prompt referrals for all races/ethnicities, universal screening strategies should be considered. Second, to ensure efficient evaluations independent of age, algorithms designed to detect early features of BA can be developed.

Social factors influencing hospital arrival time in acute ischemic stroke patients.

PubMed

Iosif, Christina; Papathanasiou, Mathilda; Staboulis, Eleftherios; Gouliamos, Athanasios

2012-04-01

This is a multi-center, hospital-based study aiming to estimate social factors influencing pre-hospital times of arrival in acute ischemic stroke, with a perspective of finding ways to reduce arrival time and to augment the number of patients eligible for intra-arterial thrombolysis. Acute ischemic stroke patients who presented at the emergency units of four major general public hospitals were registered. We assessed information concerning demographics, time of presentation, clinical situation, imaging, treatment, and socioeconomic factors. The sample was divided in two sub-samples, based on the time of arrival since onset of symptoms, and was statistically analyzed. During one calendar year (2005), 907 patients were registered. Among them 34.6% arrived in the first 6 h from symptom onset, 38.7% arrived between 6 and 24 h, 18.1% after 24 h and for 8.6% the time of onset was unknown. Younger age (P = 0.007), transfer with ambulatory service (Ρ = 0.002), living with a mate (Ρ = 0.004), and higher educational level (P < 0.005) were factors which correlated significantly with early arrival at the hospital. Instructing patients at high risk for stroke to live with a housemate appears beneficial for timely arrival at the hospital. The establishment of dedicated acute stroke call and transportation center should improve the percentage of early arrival. A national information campaign is needed to increase the level of awareness of the population concerning beneficial social behaviors and optimal reaction to symptoms of acute ischemic stroke.

Weather explains high annual variation in butterfly dispersal

PubMed Central

Rytteri, Susu; Heikkinen, Risto K.; Heliölä, Janne; von Bagh, Peter

2016-01-01

Weather conditions fundamentally affect the activity of short-lived insects. Annual variation in weather is therefore likely to be an important determinant of their between-year variation in dispersal, but conclusive empirical studies are lacking. We studied whether the annual variation of dispersal can be explained by the flight season's weather conditions in a Clouded Apollo (Parnassius mnemosyne) metapopulation. This metapopulation was monitored using the mark–release–recapture method for 12 years. Dispersal was quantified for each monitoring year using three complementary measures: emigration rate (fraction of individuals moving between habitat patches), average residence time in the natal patch, and average distance moved. There was much variation both in dispersal and average weather conditions among the years. Weather variables significantly affected the three measures of dispersal and together with adjusting variables explained 79–91% of the variation observed in dispersal. Different weather variables became selected in the models explaining variation in three dispersal measures apparently because of the notable intercorrelations. In general, dispersal rate increased with increasing temperature, solar radiation, proportion of especially warm days, and butterfly density, and decreased with increasing cloudiness, rainfall, and wind speed. These results help to understand and model annually varying dispersal dynamics of species affected by global warming. PMID:27440662

Weather explains high annual variation in butterfly dispersal.

PubMed

Kuussaari, Mikko; Rytteri, Susu; Heikkinen, Risto K; Heliölä, Janne; von Bagh, Peter

2016-07-27

Weather conditions fundamentally affect the activity of short-lived insects. Annual variation in weather is therefore likely to be an important determinant of their between-year variation in dispersal, but conclusive empirical studies are lacking. We studied whether the annual variation of dispersal can be explained by the flight season's weather conditions in a Clouded Apollo (Parnassius mnemosyne) metapopulation. This metapopulation was monitored using the mark-release-recapture method for 12 years. Dispersal was quantified for each monitoring year using three complementary measures: emigration rate (fraction of individuals moving between habitat patches), average residence time in the natal patch, and average distance moved. There was much variation both in dispersal and average weather conditions among the years. Weather variables significantly affected the three measures of dispersal and together with adjusting variables explained 79-91% of the variation observed in dispersal. Different weather variables became selected in the models explaining variation in three dispersal measures apparently because of the notable intercorrelations. In general, dispersal rate increased with increasing temperature, solar radiation, proportion of especially warm days, and butterfly density, and decreased with increasing cloudiness, rainfall, and wind speed. These results help to understand and model annually varying dispersal dynamics of species affected by global warming. © 2016 The Author(s).

Does geography or ecology best explain 'cultural' variation among chimpanzee communities?

PubMed

Kamilar, Jason M; Marshack, Joshua L

2012-02-01

Much attention has been paid to geographic variation in chimpanzee behavior, but few studies have applied quantitative techniques to explain this variation. Here, we apply methods typically utilized in macroecology to explain variation in the putative cultural traits of chimpanzees. We analyzed published data containing 39 behavioral traits from nine chimpanzee communities. We used a canonical correspondence analysis to examine the relative importance of environmental characteristics and geography, which may be a proxy for inter-community gene flow and/or social transmission, for explaining geographic variation in chimpanzee behavior. We found that geography, and longitude in particular, was the best predictor of behavioral variation. Chimpanzee communities in close longitudinal proximity to each other exhibit similar behavioral repertoires, independent of local ecological factors. No ecological variables were significantly related to behavioral variation. These results support the idea that inter-community dispersal patterns have played a major role in structuring behavioral variation. We cannot be certain whether behavioral variation has a genetic basis, is the result of innovation and diffusion, or a combination of the two. Copyright © 2011 Elsevier Ltd. All rights reserved.

Examination of Factors Explaining Coaching Strategy and Training Methodology as Correlates of Potential Doping Behavior in High-Level Swimming

PubMed Central

Liposek, Silvester; Zenic, Natasa; Saavedra, Jose M; Sekulic, Damir; Rodek, Jelena; Marinsek, Miha; Sajber, Dorica

2018-01-01

Although coaching is considered an important determinant of athletes’ potential doping behavior (PDB), there is an evident lack of studies that have examined coaching-strategy-and-training-methodology (CS&TM) in relation to PDB. This study was aimed to identify the specific associations that may exist between CS&TM -factors and other factors, and PDB in high-level swimming. The sample comprised 94 swimmers (35 females; 19.7 ± 2.3 years of age) and consisted of swimmers older than 18 years who participated in the 2017 National Championship. Variables were collected by previously validated questionnaires, with the addition of questions where athletes were asked about CS&TM to which they had been exposed. Multinomial logistic regression was applied for the criterion PDB (Negative PDB – Neutral PDB – Positive PDB). The higher risk for positive-PDB was found in males (OR: 6.58; 95%CI: 1.01-9.12); therefore, all regressions were adjusted for gender. Those swimmers who achieved better competitive result were less prone to neutral-PDB (0.41; 0.17-0.98). The positive-PDB was evidenced in those swimmers who perceived that their training was monotonous and lacked diversity (1.82; 1.41-5.11), and who were involved in training which was mostly oriented toward volume (1.76; 1.11-7.12). The lower likelihood of positive-PDB is found in those who replied that technique is practiced frequently (0.12; 0.01-0.81), those who replied that coach regularly provided the attention to explain the training aims (0.21; 0.04-0.81), and that coach frequently reviewed and discussed the quality of execution of specific tasks (0.41; 0.02-0.81). The findings on the relationships between the studied variables and PDB should be incorporated into targeted anti-doping efforts in swimming. Further studies examining sport-specific variables of CS&TM in younger swimmers and other sports are warranted. Key points The opinions about doping presence in swimming were not associated with athletes�

Explaining the Gap in Charter and Traditional Public School Teacher Turnover Rates

ERIC Educational Resources Information Center

Stuit, David A.; Smith, Thomas M.

2012-01-01

This study uses national survey data to examine why charter school teachers are more likely to turnover than their traditional public school counterparts. We test whether the turnover gap is explained by different distributions of factors that are empirically and theoretically linked to turnover risk. We find that the turnover rate of charter…

Factors influencing new graduate nurse burnout development, job satisfaction and patient care quality: a time-lagged study.

PubMed

Boamah, Sheila A; Read, Emily A; Spence Laschinger, Heather K

2017-05-01

To test a hypothesized model linking new graduate nurses' perceptions of their manager's authentic leadership behaviours to structural empowerment, short-staffing and work-life interference and subsequent burnout, job satisfaction and patient care quality. Authentic leadership and structural empowerment have been shown to reduce early career burnout among nurses. Short-staffing and work-life interference are also linked to burnout and may help explain the impact of positive, empowering leadership on burnout, which in turn influences job satisfaction and patient care quality. A time-lagged study of Canadian new graduate nurses was conducted. At Time 1, surveys were sent to 3,743 nurses (November 2012-March 2013) and 1,020 were returned (27·3% response rate). At Time 2 (May-July 2014), 406 nurses who responded at Time 1 completed surveys (39·8% response rate). Descriptive analysis was conducted in SPSS. Structural equation modelling in Mplus was used to test the hypothesized model. The hypothesized model was supported. Authentic leadership had a significant positive effect on structural empowerment, which in turn decreased both short-staffing and work-life interference. Short-staffing and work-life imbalance subsequently resulted in nurse burnout, lower job satisfaction and lower patient care quality 1 year later. The findings suggest that short-staffing and work-life interference are important factors influencing new graduate nurse burnout. Developing nurse managers' authentic leadership behaviours and working with them to create and sustain empowering work environments may help reduce burnout, increase nurse job satisfaction and improve patient care quality. © 2016 John Wiley & Sons Ltd.

USING HUMAN ACTIVITY DATA IN EXPOSURE MODELS: ANALYSIS OF DISCRIMINATING FACTORS

EPA Science Inventory

This paper tests factors thought to be important in explaining the choices people make in where they spend time. Three aggregate locations are analyzed: outdoors, indoors, and in-vehicles for two different sample groups: a year-long (longitudinal) sample of one individual and ...

Effect of climatological factors on respiratory syncytial virus epidemics

PubMed Central

NOYOLA, D. E.; MANDEVILLE, P. B.

2008-01-01

SUMMARY Respiratory syncytial virus (RSV) presents as yearly epidemics in temperate climates. We analysed the association of atmospheric conditions to RSV epidemics in San Luis Potosí, S.L.P., Mexico. The weekly number of RSV detections between October 2002 and May 2006 were correlated to ambient temperature, barometric pressure, relative humidity, vapour tension, dew point, precipitation, and hours of light using time-series and regression analyses. Of the variation in RSV cases, 49·8% was explained by the study variables. Of the explained variation in RSV cases, 32·5% was explained by the study week and 17·3% was explained by meteorological variables (average daily temperature, maximum daily temperature, temperature at 08:00 hours, and relative humidity at 08:00 hours). We concluded that atmospheric conditions, particularly temperature, partly explain the year to year variability in RSV activity. Identification of additional factors that affect RSV seasonality may help develop a model to predict the onset of RSV epidemics. PMID:18177520

What explains between-school differences in rates of sexual experience?

PubMed Central

Henderson, Marion; Butcher, Isabella; Wight, Daniel; Williamson, Lisa; Raab, Gillian

2008-01-01

Background Schools have the potential to influence their pupils' behaviour through the school's social organisation and culture, as well as through the formal curriculum. This paper provides the first attempt to explain the differences between schools in rates of reported heterosexual sexual experience amongst 15 and 16 year olds. It first examined whether variations in rates of sexual experience remained after controlling for the known predictors of sexual activity. It then examined whether these residuals, or 'school effects', were attributable to processes within the school, or were more likely to reflect characteristics of the neighbourhood. Methods Longitudinal survey data from 4,926 pupils in 24 Scottish schools were linked to qualitative and quantitative data on school processes including quality of relationships (staff-pupil, etc), classroom discipline, organisation of Personal and Social Education, school appearance and pupil morale. Multi-level modelling was used to test a range of models and the resulting 'school effects' were then interpreted using the process data. Results Overall, 42% of girls and 33% of boys reported experience of sexual intercourse, with rates by school ranging from 23% to 61%. When individual socio-economic and socio-cultural factors were taken into account the school variation dropped sharply, though pupils' attitudes and aspirations had little effect. There was very little correlation between boys' and girls' rates of sexual experience by school, after controlling for known predictors of sexual activity. Girls were more influenced by individual socio-economic factors than boys. School-level socio-economic factors were predictive even after taking account of individual socio-cultural factors, suggesting that the wider socio-economic environment further influenced young people's sexual experience. Conclusion Importantly, school processes did not explain the variation between schools in sexual experience. Rather, the variation may

Design Factors Affecting the Reaction Time for Identifying Toilet Signs: A Preliminary Study.

PubMed

Chen, Yi-Lang; Sie, Cai-Cin

2016-04-01

This study focused on the manner in which design factors affect the reaction time for identifying toilet signs. Taiwanese university students and staff members (50 men, 50 women; M age = 23.5 year, SD = 5.7) participated in the study. The 36 toilet signs were modified on three factors (six presenting styles, two figure-ground exchanges, and three colors), and the reaction time data of all participants were collected when the signs were presented in a simulation onscreen. Participants were quickest when reading Chinese text, followed by graphics and English texts. The findings also showed that men and women had different reaction times across various design combinations. These findings can serve as a reference for practically designing toilet signs, since design factors can lead to difficulties with comprehension based on reaction time measurements. © The Author(s) 2016.

Do time-invariant confounders explain away the association between job stress and workers' mental health? Evidence from Japanese occupational panel data.

PubMed

Oshio, Takashi; Tsutsumi, Akizumi; Inoue, Akiomi

2015-02-01

It is well known that job stress is negatively related to workers' mental health, but most recent studies have not controlled for unobserved time-invariant confounders. In the current study, we attempted to validate previous observations on the association between job stress and workers' mental health, by removing the effects of unobserved time-invariant confounders. We used data from three to four waves of an occupational Japanese cohort survey, focusing on 31,382 observations of 9741 individuals who participated in at least two consecutive waves. We estimated mean-centered fixed effects models to explain psychological distress in terms of the Kessler 6 (K6) scores (range: 0-24) by eight job stress indicators related to the job demands-control, effort-reward imbalance, and organizational injustice models. Mean-centered fixed effects models reduced the magnitude of the association between jobs stress and K6 scores to 44.8-54.2% of those observed from pooled ordinary least squares. However, the association remained highly significant even after controlling for unobserved time-invariant confounders for all job stress indicators. In addition, alternatively specified models showed the robustness of the results. In all, we concluded that the validity of major job stress models, which link job stress and workers' mental health, was robust, although unobserved time-invariant confounders led to an overestimation of the association. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evolutionary fields can explain patterns of high-dimensional complexity in ecology

NASA Astrophysics Data System (ADS)

Wilsenach, James; Landi, Pietro; Hui, Cang

2017-04-01

One of the properties that make ecological systems so unique is the range of complex behavioral patterns that can be exhibited by even the simplest communities with only a few species. Much of this complexity is commonly attributed to stochastic factors that have very high-degrees of freedom. Orthodox study of the evolution of these simple networks has generally been limited in its ability to explain complexity, since it restricts evolutionary adaptation to an inertia-free process with few degrees of freedom in which only gradual, moderately complex behaviors are possible. We propose a model inspired by particle-mediated field phenomena in classical physics in combination with fundamental concepts in adaptation, which suggests that small but high-dimensional chaotic dynamics near to the adaptive trait optimum could help explain complex properties shared by most ecological datasets, such as aperiodicity and pink, fractal noise spectra. By examining a simple predator-prey model and appealing to real ecological data, we show that this type of complexity could be easily confused for or confounded by stochasticity, especially when spurred on or amplified by stochastic factors that share variational and spectral properties with the underlying dynamics.

Do Lower-Body Dimensions and Body Composition Explain Vertical Jump Ability?

PubMed

Caia, Johnpaul; Weiss, Lawrence W; Chiu, Loren Z F; Schilling, Brian K; Paquette, Max R; Relyea, George E

2016-11-01

Caia, J, Weiss, LW, Chiu, LZF, Schilling, BK, Paquette, MR, and Relyea, GE. Do lower-body dimensions and body composition explain vertical jump ability? J Strength Cond Res 30(11): 3073-3083, 2016-Vertical jump (VJ) capability is integral to the level of success attained by individuals participating in numerous sport and physical activities. Knowledge of factors related to jump performance may help with talent identification and/or optimizing training prescription. Although myriad variables are likely related to VJ, this study focused on determining if various lower-body dimensions and/or body composition would explain some of the variability in performance. Selected anthropometric dimensions were obtained from 50 university students (25 men and 25 women) on 2 occasions separated by 48 or 72 hours. Estimated body fat percentage (BF%), height, body weight, hip width, pelvic width, bilateral quadriceps angle (Q-angle), and bilateral longitudinal dimensions of the feet, leg, thigh, and lower limb were obtained. Additionally, participants completed countermovement VJs. Analysis showed BF% to have the highest correlation with countermovement VJ displacement (r = -0.76, p < 0.001). When examining lower-body dimensions, right-side Q-angle displayed the strongest association with countermovement VJ displacement (r = -0.58, p < 0.001). Regression analysis revealed that 2 different pairs of variables accounted for the greatest variation (66%) in VJ: (a) BF% and sex and (b) BF% and body weight. Regression models involving BF% and lower-body dimensions explained up to 61% of the variance observed in VJ. Although the variance explained by BF% may be increased by using several lower-body dimensions, either sex identification or body weight explains comparatively more. Therefore, these data suggest that the lower-body dimensions measured herein have limited utility in explaining VJ performance.

Beyond Socioeconomics: Explaining Ethnic Group Differences in Parenting through Cultural and Immigration Processes

ERIC Educational Resources Information Center

Chao, Ruth; Kanatsu, Akira

2008-01-01

This study examined both socioeconomic and cultural factors in explaining ethnic differences in monitoring, behavioral control, and warmth--part of a series of coordinated studies presented in this special issue. Socioeconomic variables included mother's and father's educational levels, employment status, home ownership, number of siblings in the…

Stillbirth risk factors according to timing of exposure.

PubMed

Dodds, Linda; King, Will D; Fell, Deshayne B; Armson, B Anthony; Allen, Alexander; Nimrod, Carl

2006-08-01

The purpose of the present study is to identify risk factors for stillbirth and explore hypotheses about the cause of stillbirth based on the time in gestation when exposures occur. Relationships between lifestyle factors, pregnancy conditions, medication use, and occupation on risk for stillbirth were examined within a population-based case-control study. Women who had a stillbirth and a random sample of women who had a live birth between 1999 and 2001 were identified through perinatal databases in Nova Scotia and Eastern Ontario, Canada. Exposure data were collected for each month of pregnancy and analyzed within trimesters. Case-control data were converted to case-cohort data, and hazard ratios (HRs) and 95% confidence intervals (CIs) were determined from Cox proportional hazards models. This study included 105 stillbirth cases and 389 live-birth controls. Fertility treatment in the present pregnancy was associated with increased risk for stillbirth (adjusted HR, 4.0; 95% CI, 1.4-11.6). Smoking during the first trimester also was associated with increased risk for stillbirth (adjusted HR, 2.4; 95% CI, 1.2-4.9). Other risk factors included antiemetic use during the first trimester, second-trimester antibiotic use, low family income, and age older than 35 years. Risk factors identified in this study concur with findings of previous studies and support the importance of early pregnancy exposures on stillbirth risk.

An improved optimization algorithm and Bayes factor termination criterion for sequential projection pursuit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb-Robertson, Bobbie-Jo M.; Jarman, Kristin H.; Harvey, Scott D.

2005-05-28

A fundamental problem in analysis of highly multivariate spectral or chromatographic data is reduction of dimensionality. Principal components analysis (PCA), concerned with explaining the variance-covariance structure of the data, is a commonly used approach to dimension reduction. Recently an attractive alternative to PCA, sequential projection pursuit (SPP), has been introduced. Designed to elicit clustering tendencies in the data, SPP may be more appropriate when performing clustering or classification analysis. However, the existing genetic algorithm (GA) implementation of SPP has two shortcomings, computation time and inability to determine the number of factors necessary to explain the majority of the structure inmore » the data. We address both these shortcomings. First, we introduce a new SPP algorithm, a random scan sampling algorithm (RSSA), that significantly reduces computation time. We compare the computational burden of the RSS and GA implementation for SPP on a dataset containing Raman spectra of twelve organic compounds. Second, we propose a Bayes factor criterion, BFC, as an effective measure for selecting the number of factors needed to explain the majority of the structure in the data. We compare SPP to PCA on two datasets varying in type, size, and difficulty; in both cases SPP achieves a higher accuracy with a lower number of latent variables.« less

Explaining regional variations in health care utilization between Swiss cantons using panel econometric models

PubMed Central

2012-01-01

Background In spite of a detailed and nation-wide legislation frame, there exist large cantonal disparities in consumed quantities of health care services in Switzerland. In this study, the most important factors of influence causing these regional disparities are determined. The findings can also be productive for discussing the containment of health care consumption in other countries. Methods Based on the literature, relevant factors that cause geographic disparities of quantities and costs in western health care systems are identified. Using a selected set of these factors, individual panel econometric models are calculated to explain the variation of the utilization in each of the six largest health care service groups (general practitioners, specialist doctors, hospital inpatient, hospital outpatient, medication, and nursing homes) in Swiss mandatory health insurance (MHI). The main data source is 'Datenpool santésuisse', a database of Swiss health insurers. Results For all six health care service groups, significant factors influencing the utilization frequency over time and across cantons are found. A greater supply of service providers tends to have strong interrelations with per capita consumption of MHI services. On the demand side, older populations and higher population densities represent the clearest driving factors. Conclusions Strategies to contain consumption and costs in health care should include several elements. In the federalist Swiss system, the structure of regional health care supply seems to generate significant effects. However, the extent of driving factors on the demand side (e.g., social deprivation) or financing instruments (e.g., high deductibles) should also be considered. PMID:22413884

Characteristics of broadband slow earthquakes explained by a Brownian model

NASA Astrophysics Data System (ADS)

Ide, S.; Takeo, A.

2017-12-01

Brownian slow earthquake (BSE) model (Ide, 2008; 2010) is a stochastic model for the temporal change of seismic moment release by slow earthquakes, which can be considered as a broadband phenomena including tectonic tremors, low frequency earthquakes, and very low frequency (VLF) earthquakes in the seismological frequency range, and slow slip events in geodetic range. Although the concept of broadband slow earthquake may not have been widely accepted, most of recent observations are consistent with this concept. Then, we review the characteristics of slow earthquakes and how they are explained by BSE model. In BSE model, the characteristic size of slow earthquake source is represented by a random variable, changed by a Gaussian fluctuation added at every time step. The model also includes a time constant, which divides the model behavior into short- and long-time regimes. In nature, the time constant corresponds to the spatial limit of tremor/SSE zone. In the long-time regime, the seismic moment rate is constant, which explains the moment-duration scaling law (Ide et al., 2007). For a shorter duration, the moment rate increases with size, as often observed for VLF earthquakes (Ide et al., 2008). The ratio between seismic energy and seismic moment is constant, as shown in Japan, Cascadia, and Mexico (Maury et al., 2017). The moment rate spectrum has a section of -1 slope, limited by two frequencies corresponding to the above time constant and the time increment of the stochastic process. Such broadband spectra have been observed for slow earthquakes near the trench axis (Kaneko et al., 2017). This spectrum also explains why we can obtain VLF signals by stacking broadband seismograms relative to tremor occurrence (e.g., Takeo et al., 2010; Ide and Yabe, 2014). The fluctuation in BSE model can be non-Gaussian, as far as the variance is finite, as supported by the central limit theorem. Recent observations suggest that tremors and LFEs are spatially characteristic

Brazilian infant motor and cognitive development: Longitudinal influence of risk factors.

PubMed

Pereira, Keila Rg; Valentini, Nadia C; Saccani, Raquel

2016-12-01

Infant developmental delays have been associated with several risk factors, such as familial environmental, individual and demographic characteristics. The goal of this study was to longitudinally investigate the effects of maternal knowledge and practices, home environment and biological factors on infant motor and cognitive outcomes. This was a prospective cohort study with a sample of 49 infants from Southern Brazil. The infants were assessed three times over 4 months using the Alberta Infant Motor Scale and the Bayley Scale of Infant Development (Mental Development Scale). Parents completed the Daily Activities Scale of Infants, the Affordances in The Home Environment for Motor Development - Infant Scale, the Knowledge of Infant Development Inventory and a demographic questionnaire. Generalized estimating equation with Bonferroni method as the follow-up test and Spearman correlation and multivariate linear backward regression were used. Cognitive and motor scores were strongly associated longitudinally and increased over time. Associations between the home affordances, parental practices and knowledge, and motor and cognitive development over time were observed. This relationship explained more variability in motor and cognitive scores compared with biological factors. Variability in motor and cognitive development is better explained by environment and parental knowledge and practice. The investigation of factors associated with infant development allows the identification of infants at risk and the implementation of educational programs and parental training to minimize the effects of developmental delay. © 2016 Japan Pediatric Society.

Spring Temperatures Alone Cannot Explain Timing of Budburst of Boreal-Temperate Tree Species under Experimental Warming

NASA Astrophysics Data System (ADS)

Montgomery, R. A.; Reich, P. B.; Rich, R. L.; Stefanski, A.

2011-12-01

Phenology, the timing of seasonal biological events such as budburst, blossom dates, bird migration and insect development, is critical to understanding species interactions (e.g. pollination, herbivory); determines growing season length in many (i.e. seasonal) terrestrial ecosystems; and can play a role in determining species range limits. There is ample evidence that plant and animal phenology has changed in recent decades. For trees in seasonally cold climates, change is most commonly manifested as earlier budburst, likely caused by earlier onset of warming temperatures in spring. Indeed, it is often assumed that one of the major phenological responses of temperate and boreal forest ecosystems to climate change will be earlier leafing and concomitantly, a longer growing season. However, spring warming interacts with other factors such as winter chilling and photoperiod to determine timing of spring leafing. For example, warmer winters could reduce the duration and amount of chilling experienced by dormant buds and lead to delayed budburst. Despite knowledge that such interactions exist, we know little about the interactive mechanisms by which various cues influence budburst in forest tree species or whether species differ in sensitivity to those cues. This gap hinders our ability to predict phenological responses and their ecological impacts under future climate scenarios. Over the past three years, we have conducted studies of leafing phenology, germination, photosynthesis, respiration, and growth of seedlings of ten boreal-temperate tree species subjected to experimental warming using infrared heat lamps and soil heating cables. Seedlings were planted into plots receiving ambient, +1.8°C or +3.6°C temperature treatments in open, aspen forest at the Cloquet Forestry Center, Cloquet, MN, USA (46°31' N, 92°30' W, 386 m a.s.l.; 4.5°C MAT, 807 mm MAP). While all species responded to warming by advancing the absolute date of budburst, several lines of evidence

Discrimination in a universal health system: explaining socioeconomic waiting time gaps.

PubMed

Johar, Meliyanni; Jones, Glenn; Keane, Micheal P; Savage, Elizabeth; Stavrunova, Olena

2013-01-01

One of the core goals of a universal health care system is to eliminate discrimination on the basis of socioeconomic status. We test for discrimination using patient waiting times for non-emergency treatment in public hospitals. Waiting time should reflect patients' clinical need with priority given to more urgent cases. Using data from Australia, we find evidence of prioritisation of the most socioeconomically advantaged patients at all quantiles of the waiting time distribution. These patients also benefit from variation in supply endowments. These results challenge the universal health system's core principle of equitable treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

What Explains Patterns of Diversification and Richness among Animal Phyla?

PubMed Central

Jezkova, Tereza; Wiens, John J.

2016-01-01

Animal phyla vary dramatically in species richness (from 1 species to >1.2 million), but the causes of this variation remain largely unknown. Animals have also evolved striking variation in morphology and ecology, including sessile marine taxa lacking heads, eyes, limbs, and complex organs (e.g. sponges), parasitic worms (e.g. nematodes, platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs that dominate terrestrial ecosystems (arthropods, chordates). Relating this remarkable variation in traits to the diversification and richness of animal phyla is a fundamental yet unresolved problem in biology. Here, we test the impacts of 18 traits (including morphology, ecology, reproduction, and development) on diversification and richness of extant animal phyla. Using phylogenetic multiple regression, the best-fitting model includes five traits that explain ~74% of the variation in diversification rates (dioecy, parasitism, eyes/photoreceptors, a skeleton, non-marine habitat). However, a model including just three (skeleton, parasitism, habitat) explains nearly as much variation (~67%). Diversification rates then largely explain richness patterns. Our results also identify many striking traits that have surprisingly little impact on diversification (e.g. head, limbs, and complex circulatory and digestive systems). Overall, our results reveal the key factors that shape large-scale patterns of diversification and richness across >80% of all extant, described species. PMID:28221832

What Explains Patterns of Diversification and Richness among Animal Phyla?

PubMed

Jezkova, Tereza; Wiens, John J

2017-03-01

Animal phyla vary dramatically in species richness (from one species to >1.2 million), but the causes of this variation remain largely unknown. Animals have also evolved striking variation in morphology and ecology, including sessile marine taxa lacking heads, eyes, limbs, and complex organs (e.g., sponges), parasitic worms (e.g., nematodes, platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs that dominate terrestrial ecosystems (arthropods, chordates). Relating this remarkable variation in traits to the diversification and richness of animal phyla is a fundamental yet unresolved problem in biology. Here, we test the impacts of 18 traits (including morphology, ecology, reproduction, and development) on diversification and richness of extant animal phyla. Using phylogenetic multiple regression, the best-fitting model includes five traits that explain ∼74% of the variation in diversification rates (dioecy, parasitism, eyes/photoreceptors, a skeleton, nonmarine habitat). However, a model including just three (skeleton, parasitism, habitat) explains nearly as much variation (∼67%). Diversification rates then largely explain richness patterns. Our results also identify many striking traits that have surprisingly little impact on diversification (e.g., head, limbs, and complex circulatory and digestive systems). Overall, our results reveal the key factors that shape large-scale patterns of diversification and richness across >80% of all extant, described species.

Patient- and ward-level determinants of nursing time in nursing facilities.

PubMed

Laine, Juha; Noro, Anja; Finne-Soveri, Harriet; Häkkinen, Unto

2005-10-01

To explore the patient- and ward-level determinants of wage-adjusted nursing time in long-term care wards for the elderly with a view to improving efficiency of the use of labour resources. The wage-adjusted nursing time given to patients was obtained from a time measurement study. Patient characteristics were based on the Minimum Data Set 2.0 of the Resident Assessment Instrument for nursing homes. Ordinary least-squares regression analysis and multilevel modelling were used to disentangle the effect of patient- and ward-level factors on nursing time. A significant difference in wage-adjusted nursing time between wards was detected, which was partly explained by characteristics of patients in wards. The combination of patients' physical functioning and cognition and the Resource Utilization Groups RUG-III/22 resource use classification explained 20-25% of patients' nursing time over a 24-hour period. Variables related to the operational environment of the ward did not explain differences in wage-adjusted nursing time once the patient profile of the ward had been controlled for. The results also showed notable unmeasured patient and ward level effects, inefficiency and randomness in the allocation of nursing time. By improving the allocation and use of labour resources, the substantial variation in nursing time between wards could be diminished. Managers should allocate their staff primarily according to patients' resource needs.

The p Factor: One General Psychopathology Factor in the Structure of Psychiatric Disorders?

PubMed Central

Caspi, Avshalom; Houts, Renate M.; Belsky, Daniel W.; Goldman-Mellor, Sidra J.; Harrington, HonaLee; Israel, Salomon; Meier, Madeline H.; Ramrakha, Sandhya; Shalev, Idan; Poulton, Richie; Moffitt, Terrie E.

2013-01-01

Mental disorders traditionally have been viewed as distinct, episodic, and categorical conditions. This view has been challenged by evidence that many disorders are sequentially comorbid, recurrent/chronic, and exist on a continuum. Using the Dunedin Multidisciplinary Health and Development Study, we examined the structure of psychopathology, taking into account dimensionality, persistence, co-occurrence, and sequential comorbidity of mental disorders across 20 years, from adolescence to midlife. Psychiatric disorders were initially explained by three higher-order factors (Internalizing, Externalizing, and Thought Disorder) but explained even better with one General Psychopathology dimension. We have called this dimension the p factor because it conceptually parallels a familiar dimension in psychological science: the g factor of general intelligence. Higher p scores are associated with more life impairment, greater familiality, worse developmental histories, and more compromised early-life brain function. The p factor explains why it is challenging to find causes, consequences, biomarkers, and treatments with specificity to individual mental disorders. Transdiagnostic approaches may improve research. PMID:25360393

Biomechanical factors associated with time to complete a change of direction cutting maneuver.

PubMed

Marshall, Brendan M; Franklyn-Miller, Andrew D; King, Enda A; Moran, Kieran A; Strike, Siobhán C; Falvey, Éanna C

2014-10-01

Cutting ability is an important aspect of many team sports, however, the biomechanical determinants of cutting performance are not well understood. This study aimed to address this issue by identifying the kinetic and kinematic factors correlated with the time to complete a cutting maneuver. In addition, an analysis of the test-retest reliability of all biomechanical measures was performed. Fifteen (n = 15) elite multidirectional sports players (Gaelic hurling) were recruited, and a 3-dimensional motion capture analysis of a 75° cut was undertaken. The factors associated with cutting time were determined using bivariate Pearson's correlations. Intraclass correlation coefficients (ICCs) were used to examine the test-retest reliability of biomechanical measures. Five biomechanical factors were associated with cutting time (2.28 ± 0.11 seconds): peak ankle power (r = 0.77), peak ankle plantar flexor moment (r = 0.65), range of pelvis lateral tilt (r = -0.54), maximum thorax lateral rotation angle (r = 0.51), and total ground contact time (r = -0.48). Intraclass correlation coefficient scores for these 5 factors, and indeed for the majority of the other biomechanical measures, ranged from good to excellent (ICC >0.60). Explosive force production about the ankle, pelvic control during single-limb support, and torso rotation toward the desired direction of travel were all key factors associated with cutting time. These findings should assist in the development of more effective training programs aimed at improving similar cutting performances. In addition, test-retest reliability scores were generally strong, therefore, motion capture techniques seem well placed to further investigate the determinants of cutting ability.

[Relevant factors of early puberty timing in urban primary schools in Chongqing].

PubMed

Luo, Yan; Liu, Qin; Wen, Yi; Liu, Shudan; Lei, Xun; Wang, Hong

2016-05-01

To investigate the status of puberty timing and relevant factors of early puberty timing in children from grade one to four in urban primary schools of Chongqing. According to the purposive sample method, four urban primary schools in Chongqing were selected and of which 1471 children from grade one to four who have obtained informed consent were recruited. Questionnaire survey on social-demographic characteristics and family environment (e.g., age, parents' relationship, diet and lifestyle, etc), and Pubertal Development Scale (PDS) survey and physical examination (measurements of height, weight, pubertal development status, etc) were conducted. P25, P50, P75 ages of each important pubertal event were calculated by probit regression. Univariate and multivariate analysis were used to analyze relevant factors. The detection rate of early puberty timing was 17.7%, and the median ages of the onset of breast and testicular development were 10.77 and 11.48 years old, respectively. Multivariate logistic regression showed that early puberty timing occurred more likely in girls than in boys (OR = 0.561, 95% CI 0.406-0.774), and bad relationship between parents (OR = 1.320, 95% CI 1.007-1.729) and hair-products-use (OR = 1.685, 95%, CI 1.028-2.762) were risk factors of early puberty timing. Early onset of puberty in urban Chongqing is still exist. Gender, parents' relationship, and hair-products-use have an essential impact on early puberty timing.

Factor structure of paediatric timed motor examination and its relationship with IQ

PubMed Central

MARTIN, REBECCA; TIGERA, CASSIE; DENCKLA, MARTHA B; MAHONE, E MARK

2012-01-01

AIM Brain systems supporting higher cognitive and motor control develop in a parallel manner, dependent on functional integrity and maturation of related regions, suggesting neighbouring neural circuitry. Concurrent examination of motor and cognitive control can provide a window into neurological development. However, identification of performance-based measures that do not correlate with IQ has been a challenge. METHOD Timed motor performance from the Physical and Neurological Examination of Subtle Signs and IQ were analysed in 136 children aged 6 to 16 (mean age 10y 2.6mo, SD 2y 6.4mo; 98 female, 38male) attending an outpatient neuropsychology clinic and 136 right-handed comparison individuals aged 6 to 16 (mean age 10y 3.1mo, SD 2y 6.1mo; 98 female, 38male). Timed activities – three repetitive movements (toe tapping, hand patting, finger tapping) and three sequenced movements (heel–toe tap, hand pronate/supinate, finger sequencing) each performed on the right and left – were included in exploratory factor analyses. RESULTS Among comparison individuals, factor analysis yielded two factors – repetitive and sequenced movements – with the sequenced factor significantly predictive of Verbal IQ (VIQ) (ΔR2=0.018, p=0.019), but not the repetitive factor (ΔR2=0.004, p=0.39). Factor analysis within the clinical group yielded two similar factors (repetitive and sequenced), both significantly predictive of VIQ, (ΔR2=0.028, p=0.015; ΔR2=0.046, p=0.002 respectively). INTERPRETATION Among typical children, repetitive timed tasks may be independent of IQ; however, sequenced tasks share more variance, implying shared neural substrates. Among neurologically vulnerable populations, however, both sequenced and repetitive movements covary with IQ, suggesting that repetitive speed is more indicative of underlying neurological integrity. PMID:20412260

Early Life Factors and Adult Leisure Time Physical Inactivity Stability and Change.

PubMed

Pinto Pereira, Snehal M; Li, Leah; Power, Chris

2015-09-01

Physical inactivity has a high prevalence and associated disease burden. A better understanding of influences on sustaining and changing inactive lifestyles is needed. We aimed to establish whether leisure time inactivity was stable in midadulthood and whether early life factors were associated with inactivity patterns. In the 1958 British birth cohort (n = 12,271), leisure time inactivity (frequency, less than once a week) assessed at 33 and 50 yr was categorized as "never inactive," "persistently inactive," "deteriorating," or "improving." Early life factors (birth to 16 yr) were categorized into three (physical, social, and behavioral) domains. Using multinomial logistic regression, we assessed associations with inactivity persistence and change of factors within each early life domain and the three domains combined with and without adjustment for adult factors. Inactivity prevalence was similar at 33 and 50 yr (approximately 31%), but 17% deteriorated and 18% improved with age. In models adjusted for all domains simultaneously, factors associated with inactivity persistence versus never inactive were prepubertal stature (8% lower risk/height SD), poor hand control/coordination (17% higher risk/increase on four-point scale), cognition (16% lower/SD in ability) (physical); parental divorce (25% higher), class at birth (7% higher/reduction on four-point scale), minimal parental education (16% higher), household amenities (2% higher/increase in 19-point score (high = poor)) (social); and inactivity (22% higher/reduction in activity on four-point scale), low sports aptitude (47% higher), smoking (30% higher) (behavioral). All except stature, parental education, sports aptitude, and smoking were associated also with inactivity deterioration. Poor hand control/coordination was the only factor associated with improved status (13% lower/increase on four-point scale) versus persistently inactive. Adult leisure time inactivity is moderately stable. Early life factors are

Climatic suitability, isolation by distance and river resistance explain genetic variation in a Brazilian whiptail lizard.

PubMed

Oliveira, Eliana Faria; Martinez, Pablo Ariel; São-Pedro, Vinícius Avelar; Gehara, Marcelo; Burbrink, Frank Thomas; Mesquita, Daniel Oliveira; Garda, Adrian Antonio; Colli, Guarino Rinaldi; Costa, Gabriel Correa

2018-03-01

Spatial patterns of genetic variation can help understand how environmental factors either permit or restrict gene flow and create opportunities for regional adaptations. Organisms from harsh environments such as the Brazilian semiarid Caatinga biome may reveal how severe climate conditions may affect patterns of genetic variation. Herein we combine information from mitochondrial DNA with physical and environmental features to study the association between different aspects of the Caatinga landscape and spatial genetic variation in the whiptail lizard Ameivula ocellifera. We investigated which of the climatic, environmental, geographical and/or historical components best predict: (1) the spatial distribution of genetic diversity, and (2) the genetic differentiation among populations. We found that genetic variation in A. ocellifera has been influenced mainly by temperature variability, which modulates connectivity among populations. Past climate conditions were important for shaping current genetic diversity, suggesting a time lag in genetic responses. Population structure in A. ocellifera was best explained by both isolation by distance and isolation by resistance (main rivers). Our findings indicate that both physical and climatic features are important for explaining the observed patterns of genetic variation across the xeric Caatinga biome.

Harvest time of Cryptomeria japonica seeds depending on climate factors

NASA Astrophysics Data System (ADS)

Son, Seog-Gu; Kim, Hyo-Jeong; Kim, Chang-Soo; Byun, Kwang-Ok

2010-05-01

Sound seeds should have good germination rates and seed germination can be influenced by several factors. Seed picking time is regarded as one of the necessary elements to obtain sound seeds. From a clonal seed orchard of Cryptomeria japonica located in southern part of Korean peninsular, cones were picked about every 10 days from 30th of July 2005 to 30th of October in both 2005 and 2006. We have also analyzed the effects of climatic factors about two consecutive years on seed productivity. From the picked cones, seeds were collected and these germination ability, seed size and embryo shapes were investigated according to cone picking time. The 1,000-seed weight picked on 18th of August was 3.3 g and 5.3 g on 30th of September 2005and 2006. The size of seeds picked from 18th of August to 30th of September increased from 19.3 mm to 21.3 mm in length and from 15.8 mm to 18.5 mm in width. Depending on picking time, various shapes of embryos, including embryos with liquid material, jellied material and fully matured ones were observed. Germination aspects also varied throughout the test days. About two weeks after seeding in a glass petri-dish, germinal apparatuses appeared from each test seed sets which had been picked from after 10 August 2005 and 10 August 2006. The germination rates started from 10.7% from seeds picked 20 August 2006. Average germination rate in 2005 was 18.3 and 19.6 in 2006. In 2005, the highest germination rate was 34.3% from seeds picked on the 30th of September. In 2006, the highest germination rate was 31.7% for seeds picked at the same date as the 2005 seeds. After September, the highest germination rate for picked seeds decreased in both 2005 and 2006. Among the climatic factors, monthly sum of temperature and of precipitation were the main factors for maturation of C. japonica seeds. The results implied that the best cone picking time for the Korean C. japonica seed orchard to be around the end of September.

What factors influence cataract waiting list time?

PubMed Central

Churchill, A.; Vize, C.; Stewart, O.; Backhouse, O.

2000-01-01

AIMS—To determine whether there were any specific factors that influenced waiting list time (WLT) for patients undergoing cataract surgery.
METHODS—70 preoperative cataract patients were interviewed by one of the authors using a questionnaire to score visual acuity, coexisting ocular pathology and disabilities, threat to independent living/employment, and perceived visual handicap for detailed, gross, and driving vision. Individuals were analysed separately according to whether it was their first or second cataract operation.
RESULTS—The median WLT for first eye surgery was 9 months (n = 31) and 13 months for second eye surgery (n = 36). The WLT ranged from 2 to 25 months for first eyes and 0.25-18 months for second eyes. Where there was a perceived threat to independent living or employment the WLT was found to be significantly shorter than the median. A high overall score correlated with a shorter WLT. Surgical priority was also given to individuals with anisometropia >3 dioptres.
CONCLUSION—This study has demonstrated that there are specific factors that influence clinicians when prioritising patients for cataract surgery.

 PMID:10729304

The interaction of drought and habitat explain space-time patterns of establishment in saguaro (Carnegiea gigantea).

PubMed

Winkler, Daniel E; Conver, Joshua L; Huxman, Travis E; Swann, Don E

2018-03-01

The long-lived columnar saguaro cactus (Carnegiea gigantea) is among the most studied plants in the world. Long-term studies have shown saguaro establishment to be generally episodic and strongly influenced by precipitation and temperature. Water limitation through lower-than-average seasonal rainfall and elevated temperatures increasing evaporative loss can reduce survivorship of recent germinates. Thus, multi-year, extended drought could cause populations to decline as older saguaros die without replacement. Previous studies have related establishment to temporal variation in rainfall, but most studies have been on non-randomized plots in ideal habitat and thus might not have captured the full variability within the local area. We studied how saguaro establishment varied in space and which habitat features may buffer responses to drought on 36 4-ha plots located randomly across an elevation gradient, including substantial replication in landscape position (bajada, foothills, and slopes) in the two disjunct districts of Saguaro National Park in southern Arizona, USA. Recent, severe drought coincided with drastic declines in saguaro establishment across this ~25,000-ha area. Establishment patterns derived from the park-wide data set was strongly correlated with drought, but the Park's two districts and diversity of plots demonstrated substantially different population outcomes. Saguaro establishment was best explained by the interaction of drought and habitat type; establishment in bajada and foothill plots dropped to near-zero under the most severe periods of water limitation but remained higher in slope plots during the same time span. Combined with saguaro density estimates, these data suggest that the most suitable habitat type for saguaro establishment shifted to higher elevations during the time span of the recent drought. These results place into context the extent to which historical patterns of demography provide insight into future population dynamics in

Climate and Human Pressure Constraints Co-Explain Regional Plant Invasion at Different Spatial Scales

PubMed Central

García-Baquero, Gonzalo; Caño, Lidia; Biurrun, Idoia; García-Mijangos, Itziar; Loidi, Javier; Herrera, Mercedes

2016-01-01

Alien species invasion represents a global threat to biodiversity and ecosystems. Explaining invasion patterns in terms of environmental constraints will help us to assess invasion risks and plan control strategies. We aim to identify plant invasion patterns in the Basque Country (Spain), and to determine the effects of climate and human pressure on that pattern. We modeled the regional distribution of 89 invasive plant species using two approaches. First, distance-based Moran’s eigenvector maps were used to partition variation in the invasive species richness, S, into spatial components at broad and fine scales; redundancy analysis was then used to explain those components on the basis of climate and human pressure descriptors. Second, we used generalized additive mixed modeling to fit species-specific responses to the same descriptors. Climate and human pressure descriptors have different effects on S at different spatial scales. Broad-scale spatially structured temperature and precipitation, and fine-scale spatially structured human population density and percentage of natural and semi-natural areas, explained altogether 38.7% of the total variance. The distribution of 84% of the individually tested species was related to either temperature, precipitation or both, and 68% was related to either population density or natural and semi-natural areas, displaying similar responses. The spatial pattern of the invasive species richness is strongly environmentally forced, mainly by climate factors. Since individual species responses were proved to be both similarly constrained in shape and explained variance by the same environmental factors, we conclude that the pattern of invasive species richness results from individual species’ environmental preferences. PMID:27741276

Factor Structure and Scale Reliabilities of the Adjective Check List Across Time

ERIC Educational Resources Information Center

Miller, Stephen H.; And Others

1978-01-01

Investigated factor structure and scale reliabilities of Gough's Adjective Check List (ACL) and their stability over time. Employees in a community mental health center completed the ACL twice, separated by a one-year interval. After each administration, separate factor analyses were computed. All scales had highly significant test-retest…

Triggers for Autism: Genetic and Environmental Factors

PubMed Central

Matsuzaki, Hideo; Iwata, Keiko; Manabe, Takayuki; Mori, Norio

2012-01-01

This report reviews the research on the factors that cause autism. In several studies, these factors have been verified by reproducing them in autistic animal models. Clinical research has demonstrated that genetic and environmental factors play a major role in the development of autism. However, most cases are idiopathic, and no single factor can explain the trends in the pathology and prevalence of autism. At the time of this writing, autism is viewed more as a multi-factorial disorder. However, the existence of an unknown factor that may be common in all autistic cases cannot be ruled out. It is hoped that future biological studies of autism will help construct a new theory that can interpret the pathology of autism in a coherent manner. To achieve this, large-scale epidemiological research is essential. PMID:23650465

Time-Varying Risk Factors and Sexual Aggression Perpetration Among Male College Students.

PubMed

Thompson, Martie P; Kingree, Jeffrey Brooks; Zinzow, Heidi; Swartout, Kevin

2015-12-01

Preventing sexual aggression (SA) can be informed by determining if time-varying risk factors differentiate men who follow different sexual aggression risk trajectories. Data are from a longitudinal study with 795 college males surveyed at the end of each of their 4 years of college in 2008-2011. Repeated measures general linear models tested if changes in risk factors corresponded with sexual aggression trajectory membership. Changes in the risk factors corresponded with SA trajectories. Men who came to college with a history of SA but decreased their perpetration likelihood during college showed concurrent decreases in sexual compulsivity, impulsivity, hostile attitudes toward women, rape supportive beliefs, perceptions of peer approval of forced sex, and perceptions of peer pressure to have sex with many different women, and smaller increases in pornography use over their college years. Conversely, men who increased levels of SA over time demonstrated larger increases in risk factors in comparison to other trajectory groups. The odds that males engaged in sexual aggression corresponded with changes in key risk factors. Risk factors were not static and interventions designed to alter them may lead to changes in sexual aggression risk. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Explaining Discrepancies in Arrest Rates Between Black and White Male Juveniles

PubMed Central

Fite, Paula J.; Wynn, Porche’; Pardini, Dustin A.

2010-01-01

The authors investigated discrepancies in arrest rates between Black and White male juveniles by examining the role of early risk factors for arrest. Two hypotheses were evaluated: (a) Disproportionate minority arrest is due to increased exposure to early risk factors, and (b) a differential sensitivity to early risk factors contributes to disproportionate minority arrest. The study included 481 Black and White boys who were followed from childhood to early adulthood. A higher incidence of early risk factors accounted for racial differences related to any juvenile arrest, as well as differences in violence- and theft-related arrests. However, increased exposure to early risk factors did not explain race differences in drug-related arrests. Minimal support was found for the hypothesis that a differential sensitivity to risk factors accounts for disproportionate rate of minority male arrests. In sum, most racial discrepancies in juvenile male arrests were accounted for by an increased exposure to childhood risk factors. Specifically, Black boys were more likely to display early conduct problems and low academic achievement and experience poor parent–child communication, peer delinquency, and neighborhood problems, which increased their risk for juvenile arrest. PMID:19803571

Un-explained visual loss following silicone oil removal: results of the Pan American Collaborative Retina Study (PACORES) Group.

PubMed

Roca, Jose A; Wu, Lihteh; Berrocal, Maria; Rodriguez, Francisco; Alezzandrini, Arturo; Alvira, Gustavo; Velez-Montoya, Raul; Quiroz-Mercado, Hugo; Fernando Arevalo, J; Serrano, Martín; Lima, Luiz H; Figueroa, Marta; Farah, Michel; Chico, Giovanna

2017-01-01

To report the incidence and clinical features of patients that experienced un-explained visual loss following silicone oil (SO) removal. Multicenter retrospective study of patients that underwent SO removal during 2000-2012. Visual loss of ≥2 lines was considered significant. A total of 324 eyes of 324 patients underwent SO removal during the study period. Forty two (13%) eyes suffered a significant visual loss following SO removal. Twenty three (7.1%) of these eyes lost vision secondary to known causes. In the remaining 19 (5.9%) eyes, the loss of vision was not explained by any other pathology. Eleven of these 19 patients (57.9%) were male. The mean age of this group was 49.2 ± 16.4 years. Eyes that had an un-explained visual loss had a mean IOP while the eye was filled with SO of 19.6 ± 6.9 mm Hg. The length of time that the eye was filled with SO was 14.8 ± 4.4 months. In comparison, eyes that did not experience visual loss had a mean IOP of 14 ± 7.3 mm Hg ( p  < 0.0002) and a mean tamponade duration of 9.3 ± 10.9 months ( p  < 0.0001). An un-explained visual loss after SO removal was observed in 5.9% of eyes. Factors associated with this phenomenon included a higher IOP and longer SO tamponade duration.

What Factors Explain Bicycling and Walking for Commuting by ELSA-Brasil Participants?

PubMed

de Matos, Sheila Maria Alvim; Pitanga, Francisco José Gondim; Almeida, Maria da Conceição C; Queiroz, Ciro Oliveira; Dos Santos, Clarice Alves; de Almeida, Rogerio Tosta; da Silva, Ianne Tayrine Martins; Griep, Rosane Harter; Amorim, Leila Denise Alves Ferreira; Patrão, Ana Luísa; Aquino, Estela M L

2018-03-01

To analyze the factors associated with commuting by bicycling and walking in adult participants from ELSA-Brasil (Longitudinal Study of Adult Health). Cross-sectional. Six teaching/research institutions throughout Brazil. A total of 15 105 civil servants. Commuting by bicycling and walking was analyzed using the long-form International Physical Activity Questionnaire. A hierarchical model containing possible factors associated with commuting by bicycling and walking was constructed. Crude and adjusted odds ratios were calculated using multinomial logistic regression. Considering the 2 forms of commuting, 66% of the participants were being considered inactive or insufficiently active. In women, being "heavier," feeling unsafe practicing physical activity, and being a former smoker were factors negatively associated with commuting by bicycling and walking. In men, active commuting was less common among those who were overweight or had abdominal obesity, those with a negative perception of safety, and those reporting that there was nowhere suitable in the neighborhood to practice physical activity. Obesity and negative perceptions in the neighborhood are associated with inactive or insufficiently active commuting. The relevance of this finding for public health is reinforce developing policies aimed at promoting health in Brazil and in other countries with similar characteristics.

Explaining socio-economic inequalities in immunization coverage in Nigeria.

PubMed

Ataguba, John E; Ojo, Kenneth O; Ichoku, Hyacinth E

2016-11-01

Globally, in 2013 over 6 million children younger than 5 years died from either an infectious cause or during the neonatal period. A large proportion of these deaths occurred in developing countries, especially in sub-Saharan Africa. Immunization is one way to reduce childhood morbidity and deaths. In Nigeria, however, although immunization is provided without a charge at public facilities, coverage remains low and deaths from vaccine preventable diseases are high. This article seeks to assess inequalities in full and partial immunization coverage in Nigeria. It also assesses inequality in the 'intensity' of immunization coverage and it explains the factors that account for disparities in child immunization coverage in the country. Using nationally representative data, this article shows that disparities exist in the coverage of immunization to the advantage of the rich. Also, factors such as mother's literacy, region and location of the child, and socio-economic status explain the disparities in immunization coverage in Nigeria. Apart from addressing these issues, the article notes the importance of addressing other social determinants of health to reduce the disparities in immunization coverage in the country. These should be in line with the social values of communities so as to ensure acceptability and compliance. We argue that any policy that addresses these issues will likely reduce disparities in immunization coverage and put Nigeria on the road to sustainable development. © The Author 2016. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Learning to apply models of materials while explaining their properties

NASA Astrophysics Data System (ADS)

Karpin, Tiia; Juuti, Kalle; Lavonen, Jari

2014-09-01

Background:Applying structural models is important to chemistry education at the upper secondary level, but it is considered one of the most difficult topics to learn. Purpose:This study analyses to what extent in designed lessons students learned to apply structural models in explaining the properties and behaviours of various materials. Sample:An experimental group is 27 Finnish upper secondary school students and control group included 18 students from the same school. Design and methods:In quasi-experimental setting, students were guided through predict, observe, explain activities in four practical work situations. It was intended that the structural models would encourage students to learn how to identify and apply appropriate models when predicting and explaining situations. The lessons, organised over a one-week period, began with a teacher's demonstration and continued with student experiments in which they described the properties and behaviours of six household products representing three different materials. Results:Most students in the experimental group learned to apply the models correctly, as demonstrated by post-test scores that were significantly higher than pre-test scores. The control group showed no significant difference between pre- and post-test scores. Conclusions:The findings indicate that the intervention where students engage in predict, observe, explain activities while several materials and models are confronted at the same time, had a positive effect on learning outcomes.

Explaining family physicians’ beliefs about antibiotic prescription

PubMed Central

Shokouhi, Elham; Zamani-Alavijeh, Fereshteh; Araban, Marzieh

2017-01-01

Background Antibiotics are among those drugs prescribed abundantly in hospitals due to their high efficiency. However, excessive, non-logical and unnecessary use of antibiotics regardless of physicians’ recommendations is considered as a challenge. Objectives The aim of this study was to explain family physicians’ beliefs about antibiotic prescription in Ahvaz. Methods This study is part of a content-analysis qualitative research conducted in Ahvaz in 2016. Study subjects were selected according to purposive sampling and data collection continued to data saturation. Required data were collected using semi-structured in-depth interviews with participation of eight subjects. Data analysis was conducted along with conducting interviews using constant comparison analysis, and it continued to the last interview. Strength and accuracy of data were investigated by experts and participants. Results From data analysis, four major categories were extracted that were composed of 20 subcategories. They were 1) expected outcomes of antibiotics (perceived pros and cons); 2) perceived pressure to follow others’ opinions; 3) the level of access to antibiotics; and 4) individual’s perception for prescription. Conclusion Findings of this study showed that various factors affect physicians’ decisions to prescribe antibiotics and it is emphasized to consider these factors. PMID:29238498

Factors that Can Help Select the Timing for Decompressive Hemicraniectomy for Malignant MCA Stroke.

PubMed

Kamran, Saadat; Salam, Abdul; Akhtar, Naveed; Alboudi, Ayman; Kamran, Kainat; Singh, Rajvir; Amir, Numan; Inshasi, Jihad; Qidwai, Uwais; Malik, Rayaz A; Shuaib, Ashfaq

2018-03-06

In patients with malignant middle cerebral artery (MMCA) stroke, a vital clinically relevant question is determination of the speed with which infarction evolves to select the time for decompressive hemicraniectomy [DHC]. A retrospective, multicenter cross-sectional study of patients referred for DHC, based on the criteria of randomized controlled trials, was undertaken to identify factors for selecting the timing of DHC in MMCA stroke, stratified by time [< 48, 48-72, > 72 h]. Infarction volume and infarct growth rate [IGR] were measured on all CT scans. One hundred eighty-two patients [135 underwent DHC and 47 survived without DHC] were included in the analysis. After multivariate adjustment, factors showing the strongest independent association with DHC were patients < 55 years of age, septum pellucidum deviation, temporal lobe involvement, MCA with additional infarcts, and IGR on second CT. Of the five factors identified, different combinations of determining factors were observed in each subgroup. Both first and second IGRs were highest in the < 48, 48-< 72, and > 72 h [p < 0.001]. Patients who survived without surgery had the slowest IGRs. There was no association between time to DHC and infarct volume, although infarct volume was lower in patients who survived without DHC compared to the DHC subgroups. We identify the major risk factors associated with DHC in time-stratified subgroups of patients with MMCA. Evaluation of IGRs between the first and second scan and when possible second and third scan can help in selecting the timing of hemicraniectomy.

Soil Water and Temperature Explain Canopy Phenology and Onset of Spring in a Semiarid Steppe

Treesearch

Lynn M. Moore; William K. Lauenroth; David M. Bell; Daniel R. Schlaepfer

2015-01-01

It is well known that the timing of growth and development influences critical life stages of all organisms. „The seasonal dynamics of ecosystems are usually well explained by photoperiod and temperature. However, phenological patterns in water-limited ecosystems are rarely studied and insufficiently explained by these two variables. We tested how onset (i.e.,...

Explaining Disparities in Youth Aerobic Fitness and Body Mass Index: Relative Impact of Socioeconomic and Minority Status

ERIC Educational Resources Information Center

Bai, Yang; Saint-Maurice, Pedro F.; Welk, Gregory J.; Allums-Featherston, Kelly; Candelaria, Norma

2016-01-01

Background: To advance research on youth fitness promotion it is important to understand factors that may explain the disparities in fitness. Methods: We evaluated data from the FitnessGram NFL PLAY60 Partnership Project to examine school factors influencing aerobic capacity (AC) and body mass index (BMI) in schoolchildren. Individual observations…

Age and disability: explaining the wage differential.

PubMed

Gannon, Brenda; Munley, Margaret

2009-07-01

This paper estimates the level of explained and unexplained factors that contribute to the wage gap between workers with and without disabilities, providing benchmark estimates for Ireland. It separates out the confounding impact of productivity differences between disabled and non-disabled, by comparing wage differentials across three groups, disabled with limitations, disabled without limitations and non-disabled. Furthermore, data are analysed for the years 1995-2001 and two sub-samples pre and post 1998 allow us to decompose wage differentials before and after the Employment Equality Act 1998. Results are comparable to those of the UK and the unexplained component (upper bound of discrimination) is lower once we control for productivity differences. The lower bound level depends on the contribution of unobserved effects and the validity of the selection component in the decomposition model.

Individual traits and environmental factors influencing sleep timing: a study of 225 Japanese couples.

PubMed

Hida, Akiko; Kitamura, Shingo; Enomoto, Minori; Nozaki, Kentaro; Moriguchi, Yoshiya; Echizenya, Masaru; Kusanagi, Hiroaki; Mishima, Kazuo

2012-03-01

Behavioral and physiological processes, such as sleep-wakefulness, thermoregulation, and hormone secretion, exhibit 24-h rhythms in most organisms. These biological rhythms are driven by the circadian clock system and are entrained by the external environment, which in the case of humans includes social time schedules. Couples might be ideal experimental subjects to discriminate between individual traits and environmental factors, as they share lifestyle habits but not genetic backgrounds. In this study, sleep timing was compared between married Japanese couples (n = 225) who had lived together for 1 yr or more (mean 17 yrs). Additionally, the authors evaluated the influence of individual traits and environmental factors on an individual's sleep timing per each couple. The results reveal that the sleep timings of a couple are mainly associated with the chronotypes of the husband and wife, whereas the sleep timings are significantly influenced by certain environmental factors. The findings suggest that chronotype remains one of the major determinants of an individual's sleep onset and wake times. Understanding an individual's chronotype may help improve the quality of life issues surrounding sleep.

Explaining the Rise in Educational Gradients in Mortality. NBER Working Paper No. 15678

ERIC Educational Resources Information Center

Cutler, David M.; Lange, Fabian; Meara, Ellen; Richards, Seth; Ruhm, Christopher J.

2010-01-01

The long-standing inverse relationship between education and mortality strengthened substantially later in the 20th century. This paper examines the reasons for this increase. We show that behavioral risk factors are not of primary importance. Smoking has declined more for the better educated, but not enough to explain the trend. Obesity has risen…

The attribution of work environment in explaining gender differences in long-term sickness absence: results from the prospective DREAM study.

PubMed

Labriola, Merete; Holte, Kari Anne; Christensen, Karl Bang; Feveile, Helene; Alexanderson, Kristina; Lund, Thomas

2011-09-01

To identify differences in risk of long-term sickness absence between female and male employees in Denmark and to examine to what extent differences could be explained by work environment factors. A cohort of 5026 employees (49.1% women, mean age 40.4years; 50.9% men, mean age 40.2years) was interviewed in 2000 regarding gender, age, family status, socio-economic position and psychosocial and physical work environment factors. The participants were followed for 18months in order to assess their incidence of long-term sickness absence exceeding 8 consecutive weeks. 298 workers (5.9%) received sickness absence compensation for 8weeks or more. Women had an excess risk of 37% compared to men, when adjusting for age, family status and socio-economic position. Physical work environment exposures could not explain this difference, whereas differences in psychosocial work environment exposures explained 32% of the differences in risk of long-term sickness absence between men and women, causing the effect of gender to become statistically insignificant. The combined effect of physical and psychosocial factors was similar, explaining 30% of the gender difference. Differences in psychosocial work environments in terms of emotional demands, reward at work, management quality and role conflicts, explained roughly 30% of women's excess long-term sickness absence risk. Assuming women and men had identical working conditions would leave the larger part of the gender difference in long-term sickness absence from work unexplained.

Dietary tendencies as predictors of marathon time in novice marathoners.

PubMed

Wilson, Patrick B; Ingraham, Stacy J; Lundstrom, Chris; Rhodes, Gregory

2013-04-01

The effects of dietary factors such as carbohydrate (CHO) on endurance-running performance have been extensively studied under laboratory-based and simulated field conditions. Evidence from "real-life" events, however, is poorly characterized. The purpose of this observational study was to examine the associations between prerace and in-race nutrition tendencies and performance in a sample of novice marathoners. Forty-six college students (36 women and 10 men) age 21.3 ± 3.3 yr recorded diet for 3 d before, the morning of, and during a 26.2-mile marathon. Anthropometric, physiological, and performance measurements were assessed before the marathon so the associations between diet and marathon time could be included as part of a stepwise-regression model. Mean marathon time was 266 ± 42 min. A pre-marathon 2-mile time trial explained 73% of the variability in marathon time (adjusted R2 = .73, p < .001). Day-before + morning-of CHO (DBMC) was the only other significant predictor of marathon time, explaining an additional 4% of the variability in marathon time (adjusted R2 = .77, p = .006). Other factors such as age, body-mass index, gender, day-before + morning-of energy, and in-race CHO were not significant independent predictors of marathon time. In this sample of primarily novice marathoners, DBMC intake was associated with faster marathon time, independent of other known predictors. These results suggest that novice and recreational marathoners should consider consuming a moderate to high amount of CHO in the 24-36 hr before a marathon.

[Fire behavior of Mongolian oak leaves fuel bed under no-wind and zero-slope conditions. II. Analysis of the factors affecting flame length and residence time and related prediction models].

PubMed

Zhang, Ji-Li; Liu, Bo-Fei; Di, Xue-Ying; Chu, Teng-Fei; Jin, Sen

2012-11-01

Taking fuel moisture content, fuel loading, and fuel bed depth as controlling factors, the fuel beds of Mongolian oak leaves in Maoershan region of Northeast China in field were simulated, and a total of one hundred experimental burnings under no-wind and zero-slope conditions were conducted in laboratory, with the effects of the fuel moisture content, fuel loading, and fuel bed depth on the flame length and its residence time analyzed and the multivariate linear prediction models constructed. The results indicated that fuel moisture content had a significant negative liner correlation with flame length, but less correlation with flame residence time. Both the fuel loading and the fuel bed depth were significantly positively correlated with flame length and its residence time. The interactions of fuel bed depth with fuel moisture content and fuel loading had significant effects on the flame length, while the interactions of fuel moisture content with fuel loading and fuel bed depth affected the flame residence time significantly. The prediction model of flame length had better prediction effect, which could explain 83.3% of variance, with a mean absolute error of 7.8 cm and a mean relative error of 16.2%, while the prediction model of flame residence time was not good enough, which could only explain 54% of variance, with a mean absolute error of 9.2 s and a mean relative error of 18.6%.

Sexual possibility situations and sexual behaviors among young adolescents: the moderating role of protective factors.

PubMed

DiLorio, Colleen; Dudley, William N; Soet, Johanna E; McCarty, Frances

2004-12-01

To examine sexual possibility situations (SPS) and protective practices associated with involvement in intimate sexual behaviors and the initiation of sexual intercourse among young adolescents and to determine if protective factors moderate the relationship between SPS and sexual behaviors. Data for these analyses were obtained from the baseline assessment for adolescents conducted as part of an HIV prevention study called "Keepin' it R.E.A.L.!" The study was conducted with a community-based organization (CBO) in an urban area serving a predominantly African-American population. In addition to items assessing SPS, intimate sexual behaviors, and initiation of sexual intercourse, adolescents provided information on the following protective factors: educational goals, self-concept, future time perspective, orientation to health, self-efficacy, outcome expectations, parenting, communication, values, and prosocial activities. Background personal information, including age and gender, was also collected. The analyses were conducted on data from 491 predominantly African-American adolescents, 61% of whom were boys. Variables were combined to form SPS and protective indices that were used in the first set of regression analyses. In a second set of analyses, the indices were unbundled and individual variables were entered into regression analyses. Both SPS and protective indices explained significant portions of variance in intimate sexual behaviors, and the SPS index explained a significant portion of variance in the initiation of sexual intercourse. The regression analysis using the unbundled SPS and protective factors revealed the following statistically significant predictors for intimate sexual behaviors: age, gender, time alone with groups of peers, time alone with a member of the opposite sex, behavior self-concept, popularity self-concept, self-efficacy for abstinence, outcome expectations for abstinence, parental control, personal values, and parental values. A

Factors affecting red blood cell storage age at the time of transfusion.

PubMed

Dzik, Walter H; Beckman, Neil; Murphy, Michael F; Delaney, Meghan; Flanagan, Peter; Fung, Mark; Germain, Marc; Haspel, Richard L; Lozano, Miguel; Sacher, Ronald; Szczepiorkowski, Zbigniew; Wendel, Silvano

2013-12-01

Clinical trials are investigating the potential benefit resulting from a reduced maximum storage interval for red blood cells (RBCs). The key drivers that determine RBC age at the time of issue vary among individual hospitals. Although progressive reduction in the maximum storage period of RBCs would be expected to result in smaller hospital inventories and reduced blood availability, the magnitude of the effect is unknown. Data on current hospital blood inventories were collected from 11 hospitals and three blood centers in five nations. A general predictive model for the age of RBCs at the time of issue was developed based on considerations of demand for RBCs in the hospital. Age of RBCs at issue is sensitive to the following factors: ABO group, storage age at the time of receipt by the hospital, the restock interval, inventory reserve, mean demand, and variation in demand. A simple model, based on hospital demand, may serve as the basis for examining factors affecting the storage age of RBCs in hospital inventories. The model suggests that the age of RBCs at the time of their issue to the patient depends on factors external to the hospital transfusion service. Any substantial change in the expiration date of stored RBCs will need to address the broad variation in demand for RBCs while attempting to balance considerations of availability and blood wastage. © 2013 American Association of Blood Banks.

Changes in Habitat Structure May Explain Decrease in Reintroduced Mohor Gazelle Population in the Guembeul Fauna Reserve, Senegal

PubMed Central

Moreno, Eulalia; Sane, Abibou; Benzal, Jesús; Ibáñez, Belén; Sanz-Zuasti, Joaquín; Espeso, Gerardo

2012-01-01

Simple Summary The reintroduction of plants and animals to the wild is an important technique to save endangered species from extinction. To perform post release monitoring is crucial to evaluate reintroduction outcomes. A Mohor gazelle reintroduction programme took place in Senegal in 1984. We attempt to explain why the size of the reintroduced gazelle population has diminished in recent years. We suggest that changes in habitat structure occurred over time and have very likely reduced the amount of suitable habitat for this species. Abstract Reintroduction is a widespread method for saving populations of endangered species from extinction. In spite of recent reviews, it is difficult to reach general conclusions about its value as a conservation tool, as authors are reluctant to publish unsuccessful results. The Mohor gazelle is a North African gazelle, extinct in the wild. Eight individuals were reintroduced in Senegal in 1984. The population grew progressively, albeit slowly, during the first 20 years after release, but then declined dramatically, until the population in 2009 was estimated at no more than 13–15 individuals. This study attempts to determine the likelihood of gazelle-habitat relationships to explain why the size of the gazelle population has diminished. Our results show that the Mohor gazelle in Guembeul is found in open habitats with less developed canopy where the grass is shorter, suggesting the possibility that changes in habitat structure have taken place during the time the gazelles have been in the Reserve, reducing the amount of suitable habitat. Reintroduction design usually concentrates on short-term factors that may affect survival of the released animals and their descendants (short-term achievement), while the key factors for assessing its success may be those that affect the long-term evolution of the population. PMID:26487026

Iron absorption from Southeast Asian diets. II. Role of various factors that might explain low absorption.

PubMed

Hallberg, L; Björn-Rasmussen, E; Rossander, L; Suwanik, R

1977-04-01

Previously reported levels of iron absorption from common Southeast Asian meals composed of rice, vegetables, and spices were too low to be consistent with the known prevalence of iron deficiency. In the present paper the cause of the low absorption was systematically sought. Variables investigated comprised methodological errors, factors in the diet such as certain foodstuffs, or contaminants inhibiting the absorption and characteristics of the subjects accompanied by malabsorption of dietary iron. The latter was excluded by comparing the absorption from both wheat rolls and a composit rice meal in Thai and Swedish women using the absorption of a small dose of ferrous ascorbate as a common basis of comparison. Two main factors were identified as causing the low absorption in the previous studies: the homogenization of the labeled meals before serving and the use of rice flour instead of rice. Iron absorption from nonhomogenized meals of identical composition as studied previously was many times higher (on an average 0.16 mg) and was consistent with the actual prevalence of iron deficiency in lower socioeconomic groups of Thais mainly consuming the simple meals studied. Recent modifications of the method to measure nonheme iron absorption from composite meals have thus not only made the determination simpler but also more accurate.

Social determinants and lifestyle risk factors only partially explain the higher prevalence of food insecurity among Aboriginal and Torres Strait Islanders in the Australian state of Victoria: a cross-sectional study

PubMed Central

2014-01-01

Background The prevalence of food insecurity is substantially higher among Australians of Aboriginal or Torres Strait Islander descent. The purpose of this study is to explain the relationship between food insecurity and Aboriginal and Torres Islander status in the state of Victoria. Methods Data were obtained from the 2008 Victorian Population Health Survey; a cross-sectional landline computer-assisted telephone interview survey of 34,168 randomly selected Victorians aged 18 years and older; including 339 Aboriginal and Torres Strait Islanders. We categorised a respondent as food insecure, if in the previous 12 months, they reported having run out of food and not being able to afford to buy more. We used multivariable logistic regression to adjust for age, sex, socioeconomic status (household income), lifestyle risk factors (smoking, alcohol consumption and obesity), social support (ability to get help from family, friends or neighbours), household composition (lone parent status, household with a child, and household size), and geographic location (rurality). Results Aboriginal and Torres Strait Islanders (20.3%) were more likely than their non-Aboriginal and Torres Strait Islander counterparts (5.4%) to have experienced food insecurity; odds ratio (OR) = 4.5 (95% CI; 2.7-7.4). Controlling for age, SES, smoking, obesity and inability to get help from family or friends reduced the odds ratio by 38%; ORadjusted = 2.8 (1.6-5.0). Conclusions Social determinants and lifestyle risk factors only partially explained the higher prevalence of food insecurity among Aboriginal and Torres Strait Islanders in Victoria. Further research is needed to explain the disparity in food insecurity between the two populations in order to inform and guide corrective action. PMID:24924598

Sickness absence: could gender divide be explained by occupation, income, mental distress and health?

PubMed

Smeby, Lisbeth; Bruusgaard, Dag; Claussen, Bjørgulf

2009-09-01

Women have more spells of sickness absence than men but the reasons for this are unknown. We wanted to see if occupation, working conditions, income, health and mental distress may explain this gender difference. In a health survey in 2000-01 of all Oslo inhabitants aged 40, 45, and 59/60 years, 11,072 (48.7%) participated. Survey data were linked to the National Insurance Administration and Statistics Norway for the 8,174 eligible for sickness pay in the next four years. Occupation, working conditions, general health and mental distress were self-reported, and income was from official statistics. Long-term sickness absence (>16 days) was calculated for 2001-04 as cumulative incidence and number of days reimbursed. Cumulative incidence was 50.1% for women and 34.7% for men in the four years after the survey. An age-adjusted female overweight of 48% was only reduced to 41% by adjusting for occupation, working conditions, income, self-reported health and mental distress. Duration of long-term sickness absence was 17 days more for women than for men, and was not influenced by adjustments. We have not explained why women have more sickness absence than men, either by work-related factors or by general health or mental distress. Factors explaining the gender divide should be sought elsewhere.

How to explain variations in sea cliff erosion rate?

NASA Astrophysics Data System (ADS)

Prémaillon, Melody; Regard, Vincent; Dewez, Thomas

2017-04-01

Every rocky coast of the world is eroding at different rate (cliff retreat rates). Erosion is caused by a complex interaction of multiple sea weather factors. While numerous local studies exist and explain erosion processes on specific sites, global studies lack. We started to compile many of those local studies and analyse their results with a global point of view in order to quantify the various parameters influencing erosion rates. In other words: is erosion more important in energetic seas? Are chalk cliff eroding faster in rainy environment? etc. In order to do this, we built a database based on literature and national erosion databases. It now contains 80 publications which represents 2500 cliffs studied and more than 3500 erosion rate estimates. A statistical analysis was conducted on this database. On a first approximation, cliff lithology is the only clear signal explaining erosion rate variation: hard lithologies are eroding at 1cm/y or less, whereas unconsolidated lithologies commonly erode faster than 10cm/y. No clear statistical relation were found between erosion rate and external parameters such as sea energy (swell, tide) or weather condition, even on cliff with similar lithology.

Explaining Constrains Causal Learning in Childhood

ERIC Educational Resources Information Center

Walker, Caren M.; Lombrozo, Tania; Williams, Joseph J.; Rafferty, Anna N.; Gopnik, Alison

2017-01-01

Three experiments investigate how self-generated explanation influences children's causal learning. Five-year-olds (N = 114) observed data consistent with two hypotheses and were prompted to explain or to report each observation. In Study 1, when making novel generalizations, explainers were more likely to favor the hypothesis that accounted for…

Explaining the Gender Wealth Gap

PubMed Central

Ruel, Erin; Hauser, Robert M.

2013-01-01

To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

Macro-organizational factors, the incidence of work disability, and work ability among the total workforce of home care workers in Sweden.

PubMed

Dellve, Lotta; Karlberg, Catarina; Allebeck, Peter; Herloff, Birgitta; Hagberg, Mats

2006-01-01

To investigate the importance of macro-organizational factors, i.e. organizational sociodemographic and socioeconomic preconditions, of the municipal incidence of long-term sick leave, disability pension, and prevalence of workers with long-term work ability among home care workers. In an ecological study design, data from national databases were combined by record linkage. Descriptive and analytical statistics were used to estimate and interpret macro-organizational factors (economic resources, region, unemployment, employment, occupational rehabilitation, return to work, age structures of inhabitants and home care workers). The incidence of long-term sick leave among female home care workers was twice as high as that of male home care workers, and incidence of disability pension was about four times as high for the women. A great variation in municipal incidence of long-term sick leave, disability pension, and long-term work ability (101-264, 0.6-19.6, and 913-1,279 per 1,000 full-time equivalent workers and year) was also found. The strongest single factor for long-term work ability was a high proportion of part-time or hourly paid employees, which explained 35% of the municipal variation. Macro-organizational factors explained long-term work ability (47-62% explained variance) better than long-term sick leave (33% explained variance). There was a low rehabilitation activity; only 2% received occupational rehabilitation and 5% of those on sick leave longer than 2 weeks returned to work within 30 days. The differences in the municipal proportion of work ability incidence indicate a preventive potential, especially related to employment and return to work after sick leave.

Factors Affecting Retention of First-Time, Full-Time Freshmen Students at Higher Education Institutions within the Appalachian College Association

ERIC Educational Resources Information Center

Swafford, Stacy James

2017-01-01

This study examined factors that may affect the retention of first-time, full-time college freshmen to sophomore year. Institutions in the Appalachian College Association (ACA) were invited to participate, and nine of the 35 member schools provided data. The research questions were (1) Is there a relationship between retention for students'…

Explaining Human Behavior.

ERIC Educational Resources Information Center

Olson, Alton T.; And Others

The Deductive-Nomological (D-N) model of human behavior is useful and provides the most objective explanation when it is appropriate but it is not necessarily an all-inclusive statement. For instance, explaining human behavior is always an act that entails languages and theories that are value laden and reveal human choices; however the D-N model…

Three-factor models versus time series models: quantifying time-dependencies of interactions between stimuli in cell biology and psychobiology for short longitudinal data.

PubMed

Frank, Till D; Kiyatkin, Anatoly; Cheong, Alex; Kholodenko, Boris N

2017-06-01

Signal integration determines cell fate on the cellular level, affects cognitive processes and affective responses on the behavioural level, and is likely to be involved in psychoneurobiological processes underlying mood disorders. Interactions between stimuli may subjected to time effects. Time-dependencies of interactions between stimuli typically lead to complex cell responses and complex responses on the behavioural level. We show that both three-factor models and time series models can be used to uncover such time-dependencies. However, we argue that for short longitudinal data the three factor modelling approach is more suitable. In order to illustrate both approaches, we re-analysed previously published short longitudinal data sets. We found that in human embryonic kidney 293 cells cells the interaction effect in the regulation of extracellular signal-regulated kinase (ERK) 1 signalling activation by insulin and epidermal growth factor is subjected to a time effect and dramatically decays at peak values of ERK activation. In contrast, we found that the interaction effect induced by hypoxia and tumour necrosis factor-alpha for the transcriptional activity of the human cyclo-oxygenase-2 promoter in HEK293 cells is time invariant at least in the first 12-h time window after stimulation. Furthermore, we applied the three-factor model to previously reported animal studies. In these studies, memory storage was found to be subjected to an interaction effect of the beta-adrenoceptor agonist clenbuterol and certain antagonists acting on the alpha-1-adrenoceptor / glucocorticoid-receptor system. Our model-based analysis suggests that only if the antagonist drug is administer in a critical time window, then the interaction effect is relevant. © The authors 2016. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

Herzberg, Hygiene and the Motivation to Reuse: Towards a Three-Factor Theory to Explain Motivation to Share and Use OER

ERIC Educational Resources Information Center

Pegler, Chris

2012-01-01

The list of barriers and enablers that influence the use of open educational resources (OER) is extensive. Factors and influences relating to reuse may have been noted within projects, operating within a short time span, or within specific conditions which limit generalizability. Evidence of reuse in practice has often emerged as isolated examples…

Depressive status explains a significant amount of the variance in COPD assessment test (CAT) scores

PubMed Central

Miravitlles, Marc; Molina, Jesús; Quintano, José Antonio; Campuzano, Anna; Pérez, Joselín; Roncero, Carlos

2018-01-01

Background COPD assessment test (CAT) is a short, easy-to-complete health status tool that has been incorporated into the multidimensional assessment of COPD in order to guide therapy; therefore, it is important to understand the factors determining CAT scores. Methods This is a post hoc analysis of a cross-sectional, observational study conducted in respiratory medicine departments and primary care centers in Spain with the aim of identifying the factors determining CAT scores, focusing particularly on the cognitive status measured by the Mini-Mental State Examination (MMSE) and levels of depression measured by the short Beck Depression Inventory (BDI). Results A total of 684 COPD patients were analyzed; 84.1% were men, the mean age of patients was 68.7 years, and the mean forced expiratory volume in 1 second (%) was 55.1%. Mean CAT score was 21.8. CAT scores correlated with the MMSE score (Pearson’s coefficient r=−0.371) and the BDI (r=0.620), both p<0.001. In the multivariate analysis, the usual COPD severity variables (age, dyspnea, lung function, and comorbidity) together with MMSE and BDI scores were significantly associated with CAT scores and explained 45% of the variability. However, a model including only MMSE and BDI scores explained up to 40% and BDI alone explained 38% of the CAT variance. Conclusion CAT scores are associated with clinical variables of severity of COPD. However, cognitive status and, in particular, the level of depression explain a larger percentage of the variance in the CAT scores than the usual COPD clinical severity variables. PMID:29563782

Depressive status explains a significant amount of the variance in COPD assessment test (CAT) scores.

PubMed

Miravitlles, Marc; Molina, Jesús; Quintano, José Antonio; Campuzano, Anna; Pérez, Joselín; Roncero, Carlos

2018-01-01

COPD assessment test (CAT) is a short, easy-to-complete health status tool that has been incorporated into the multidimensional assessment of COPD in order to guide therapy; therefore, it is important to understand the factors determining CAT scores. This is a post hoc analysis of a cross-sectional, observational study conducted in respiratory medicine departments and primary care centers in Spain with the aim of identifying the factors determining CAT scores, focusing particularly on the cognitive status measured by the Mini-Mental State Examination (MMSE) and levels of depression measured by the short Beck Depression Inventory (BDI). A total of 684 COPD patients were analyzed; 84.1% were men, the mean age of patients was 68.7 years, and the mean forced expiratory volume in 1 second (%) was 55.1%. Mean CAT score was 21.8. CAT scores correlated with the MMSE score (Pearson's coefficient r =-0.371) and the BDI ( r =0.620), both p <0.001. In the multivariate analysis, the usual COPD severity variables (age, dyspnea, lung function, and comorbidity) together with MMSE and BDI scores were significantly associated with CAT scores and explained 45% of the variability. However, a model including only MMSE and BDI scores explained up to 40% and BDI alone explained 38% of the CAT variance. CAT scores are associated with clinical variables of severity of COPD. However, cognitive status and, in particular, the level of depression explain a larger percentage of the variance in the CAT scores than the usual COPD clinical severity variables.

Investigating Factors Related to the Effects of Time-Out on Stuttering in Adults

ERIC Educational Resources Information Center

Franklin, Diane E.; Taylor, Catherine L.; Hennessey, Neville W.; Beilby, Janet M.

2008-01-01

Background: Response-contingent time-out has been shown to be an effective technique for enhancing fluency in people who stutter. However, the factors that determine individual responsiveness to time-out are not well understood. Aims: The study investigated the effectiveness of using response-contingent time-out to reduce stuttering frequency in…

Risk factors for asthma and timing of exposure among first generation Arab immigrants: a pilot effort to elucidate the role of exposure to risk factors over multiple life stages

EPA Science Inventory

Considerable controversy exists over the role of aero-allergens in asthma etiology. Some studies show increased risk with microbe and allergen exposure, while others show decreased risk. These discrepancies may be explained by timing of exposure. Previous research suggests that e...

The Path to Graduation: Factors Predicting On-Time Graduation Rates

ERIC Educational Resources Information Center

Letkiewicz, Jodi; Lim, Hanna; Heckman, Stuart; Bartholomae, Suzanne; Fox, Jonathan J.; Montalto, Catherine P.

2014-01-01

This study uses an integrative persistence model to examine college students' expected time-to-degree as a function of sociological and economic factors. The data used in this study are from the 2010 Ohio Student Financial Wellness Survey (SFWS), a web-based survey of undergraduate college students. Of the students surveyed, 25% indicated that…

Groundwater similarity across a watershed derived from time-warped and flow-corrected time series

NASA Astrophysics Data System (ADS)

Rinderer, M.; McGlynn, B. L.; van Meerveld, H. J.

2017-05-01

Information about catchment-scale groundwater dynamics is necessary to understand how catchments store and release water and why water quantity and quality varies in streams. However, groundwater level monitoring is often restricted to a limited number of sites. Knowledge of the factors that determine similarity between monitoring sites can be used to predict catchment-scale groundwater storage and connectivity of different runoff source areas. We used distance-based and correlation-based similarity measures to quantify the spatial and temporal differences in shallow groundwater similarity for 51 monitoring sites in a Swiss prealpine catchment. The 41 months long time series were preprocessed using Dynamic Time-Warping and a Flow-corrected Time Transformation to account for small timing differences and bias toward low-flow periods. The mean distance-based groundwater similarity was correlated to topographic indices, such as upslope contributing area, topographic wetness index, and local slope. Correlation-based similarity was less related to landscape position but instead revealed differences between seasons. Analysis of variance and partial Mantel tests showed that landscape position, represented by the topographic wetness index, explained 52% of the variability in mean distance-based groundwater similarity, while spatial distance, represented by the Euclidean distance, explained only 5%. The variability in distance-based similarity and correlation-based similarity between groundwater and streamflow time series was significantly larger for midslope locations than for other landscape positions. This suggests that groundwater dynamics at these midslope sites, which are important to understand runoff source areas and hydrological connectivity at the catchment scale, are most difficult to predict.

Using Balanced Time Perspective to Explain Well-Being and Planning in Retirement

PubMed Central

Mooney, Anna; Earl, Joanne K.; Mooney, Carl H.; Bateman, Hazel

2017-01-01

The notion of whether people focus on the past, present or future, and how it shapes their behavior is known as Time Perspective. Fundamental to the work of two of its earliest proponents, Zimbardo and Boyd (2008), was the concept of balanced time perspective and its relationship to wellness. A person with balanced time perspective can be expected to have a flexible temporal focus of mostly positive orientations (past-positive, present-hedonistic, and future) and much less negative orientations (past-negative and present-fatalistic). This study measured deviation from balanced time perspective (DBTP: Zhang et al., 2013) in a sample of 243 mature adults aged 45 to 91 years and explored relationships to Retirement Planning, Depression, Anxiety, Stress, Positive Mood, and Negative Mood. Results indicate that DBTP accounts for unexplained variance in the outcome measures even after controlling for demographic variables. DBTP was negatively related to Retirement Planning and Positive Mood and positively related to Depression, Anxiety, Stress, and Negative Mood. Theoretical and practical implications regarding balanced time perspective are discussed. PMID:29081757

Using Balanced Time Perspective to Explain Well-Being and Planning in Retirement.

PubMed

Mooney, Anna; Earl, Joanne K; Mooney, Carl H; Bateman, Hazel

2017-01-01

The notion of whether people focus on the past, present or future, and how it shapes their behavior is known as Time Perspective. Fundamental to the work of two of its earliest proponents, Zimbardo and Boyd (2008), was the concept of balanced time perspective and its relationship to wellness. A person with balanced time perspective can be expected to have a flexible temporal focus of mostly positive orientations (past-positive, present-hedonistic, and future) and much less negative orientations (past-negative and present-fatalistic). This study measured deviation from balanced time perspective (DBTP: Zhang et al., 2013) in a sample of 243 mature adults aged 45 to 91 years and explored relationships to Retirement Planning, Depression, Anxiety, Stress, Positive Mood, and Negative Mood. Results indicate that DBTP accounts for unexplained variance in the outcome measures even after controlling for demographic variables. DBTP was negatively related to Retirement Planning and Positive Mood and positively related to Depression, Anxiety, Stress, and Negative Mood. Theoretical and practical implications regarding balanced time perspective are discussed.

Ideas, Institutions, and School Curricula: Explaining Variation between England and France

ERIC Educational Resources Information Center

Haus, Leah

2015-01-01

This study raises the question of why the French secondary school history curricula introduced in the late 2000s prescribed more extensive coverage of plural histories than did secondary school history curricula for English schools introduced in the same time period. Both countries share similar societal diversity. To explain the variation in…

Explaining low rates of sustained use of siphon water filter: evidence from follow-up of a randomised controlled trial in Bangladesh.

PubMed

Najnin, Nusrat; Arman, Shaila; Abedin, Jaynal; Unicomb, Leanne; Levine, David I; Mahmud, Minhaj; Leder, Karin; Yeasmin, Farzana; Luoto, Jill E; Albert, Jeff; Luby, Stephen P

2015-04-01

To assess sustained siphon filter usage among a low-income population in Bangladesh and study relevant motivators and barriers. After a randomised control trial in Bangladesh during 2009, 191 households received a siphon water filter along with educational messages. Researchers revisited households after 3 and 6 months to assess filter usage and determine relevant motivators and barriers. Regular users were defined as those who reported using the filter most of the time and were observed to be using the filter at follow-up visits. Integrated behavioural model for water, sanitation and hygiene (IBM-WASH) was used to explain factors associated with regular filter use. Regular filter usage was 28% at the 3-month follow-up and 21% at the 6-month follow-up. Regular filter users had better quality water at the 6-month, but not at the 3-month visit. Positive predictors of regular filter usage explained through IBM-WASH at both times were willingness to pay >US$1 for filters, and positive attitude towards filter use (technology dimension at individual level); reporting boiling drinking water at baseline (psychosocial dimension at habitual level); and Bengali ethnicity (contextual dimension at individual level). Frequently reported barriers to regular filter use were as follows: considering filter use an additional task, filter breakage and time required for water filtering (technology dimension at individual level). The technological, psychosocial and contextual dimensions of IBM-WASH contributed to understanding the factors related to sustained use of siphon filter. Given the low regular usage rate and the hardware-related problems reported, the contribution of siphon filters to improving water quality in low-income urban communities in Bangladesh is likely to be minimal. © 2014 John Wiley & Sons Ltd.

Explaining formation of Astronomical Jets using Dynamic Universe Model

NASA Astrophysics Data System (ADS)

Naga Parameswara Gupta, Satyavarapu

2016-07-01

Astronomical jets are observed from the centres of many Galaxies including our own Milkyway. The formation of such jet is explained using SITA simulations of Dynamic Universe Model. For this purpose the path traced by a test neutron is calculated and depicted using a set up of one densemass of the mass equivalent to mass of Galaxy center, 90 stars with similar masses of stars near Galaxy center, mass equivalents of 23 Globular Cluster groups, 16 Milkyway parts, Andromeda and Triangulum Galaxies at appropriate distances. Five different kinds of theoretical simulations gave positive results The path travelled by this test neutron was found to be an astronomical jet emerging from Galaxy center. This is another result from Dynamic Universe Model. It solves new problems like a. Variable Mass Rocket Trajectory Problem b. Explaining Very long baseline interferometry (VLBI) observations c. Astronomical jets observed from Milkyway Center d. Prediction of Blue shifted Galaxies e. Explaining Pioneer Anomaly f. Prediction of New Horizons satellite trajectory etc. Dynamic Universe Model never reduces to General relativity on any condition. It uses a different type of mathematics based on Newtonian physics. This mathematics used here is simple and straightforward. As there are no differential equations present in Dynamic Universe Model, the set of equations give single solution in x y z Cartesian coordinates for every point mass for every time step

Television Time among Brazilian Adolescents: Correlated Factors are Different between Boys and Girls

PubMed Central

Tremblay, Mark Stephen; Gonçalves, Eliane Cristina de Andrade; Silva, Roberto Jerônimo dos Santos

2014-01-01

Objective. The aim of this study was to identify the prevalence of excess television time and verify correlated factors in adolescent males and females. Methods. This cross-sectional study included 2,105 adolescents aged from 13 to 18 years from the city of Aracaju, Northeastern Brazil. Television time was self-reported, corresponding to the time spent watching television in a typical week. Several correlates were examined including age, skin color, socioeconomic status, parent education, physical activity level, consumption of fruits and vegetables, smoking status, alcohol use, and sports team participation. Results. The prevalence excess television time (≥2 hours/day) in girls and boys was 70.9% and 66.2%, respectively. Girls with low socioeconomic status or inadequate consumption of fruits and vegetables were more likely to have excess television time. Among boys, those >16 years of age or with black skin color were more likely to have excess television time. Conclusions. Excess television time was observed in more than two-thirds of adolescents, being more evident in girls. Correlated factors differed according to sex. Efforts to reduce television time among Brazilian adolescents, and replace with more active pursuits, may yield desirable public health benefits. PMID:24723826

Effect of Display Factors on Chinese Reading Times, Comprehension Scores and Preferences

ERIC Educational Resources Information Center

Chan, A.H.S.; Lee, P.S.K.

2005-01-01

This paper presents the results of research on elemental standard reading time estimates for traditional Chinese characters on computer displays and explores the factors that may affect the time estimates. Seventy-two native Chinese readers, aged 19 to 24, were asked to read 16 simple passages and then answer four multiple-choice questions.…

Predisposing factors for atrial fibrillation in the elderly

PubMed Central

Wasmer, Kristina; Eckardt, Lars; Breithardt, Günter

2017-01-01

Atrial fibrillation (AF) in the elderly occurs as a consequence of cardiovascular aging and an age related increase of comorbidity. Several predisposing factors for AF have been identified for the overall AF population. Most of them, cardiovascular disease in particular, play a role in younger and older patients. The longer time period during which these risk factors can cause structural changes that ultimately lead to AF may, at least in part, explain the association between age and AF. In addition, less well defined age-related changes in cellular electrophysiologic properties and structure predispose to AF in the elderly. PMID:28592961

Ambiguity in the processing of Mandarin Chinese relative clauses: One factor cannot explain it all

PubMed Central

Mansbridge, Michael P.; Tamaoka, Katsuo; Xiong, Kexin; Verdonschot, Rinus G.

2017-01-01

This study addresses the question of whether native Mandarin Chinese speakers process and comprehend subject-extracted relative clauses (SRC) more readily than object-extracted relative clauses (ORC) in Mandarin Chinese. Presently, this has been a hotly debated issue, with various studies producing contrasting results. Using two eye-tracking experiments with ambiguous and unambiguous RCs, this study shows that both ORCs and SRCs have different processing requirements depending on the locus and time course during reading. The results reveal that ORC reading was possibly facilitated by linear/temporal integration and canonicity. On the other hand, similarity-based interference made ORCs more difficult, and expectation-based processing was more prominent for unambiguous ORCs. Overall, RC processing in Mandarin should not be broken down to a single ORC (dis)advantage, but understood as multiple interdependent factors influencing whether ORCs are either more difficult or easier to parse depending on the task and context at hand. PMID:28594939

Ureteric stent dwelling time: a risk factor for post-ureteroscopy sepsis.

PubMed

Nevo, Amihay; Mano, Roy; Baniel, Jack; Lifshitz, David A

2017-07-01

To evaluate the association between stent dwelling time and sepsis after ureteroscopy, and identify risk factors for sepsis in this setting. The prospectively collected database of a single institution was queried for all patients who underwent ureteroscopy for stone extraction between 2010 and 2016. Demographic, clinical, preoperative and operative data were collected. The primary study endpoint was sepsis within 48 h of ureteroscopy. Logistic regressions were performed to identify predictors of post-ureteroscopy sepsis in the ureteroscopy cohort and specifically in patients with prior stent insertion. Between October 2010 and April 2016, 1 256 patients underwent ureteroscopy for stone extraction. Risk factors for sepsis included prior stent placement, female gender and Charlson comorbidity index. A total of 601 patients had a ureteric stent inserted before the operation and were included in the study cohort, in which the median age was 56 years, 90 patients were women (30%), and 97 patients were treated for positive preoperative urine cultures (16.1%). Postoperative sepsis, <48 h after surgery, occurred in eight (1.2%) non-stented patients and in 28 patients (4.7%) with prior stent insertion. Sepsis rates after stent dwelling times of 1, 2, 3 and >3 months were 1, 4.9, 5.5 and 9.2%, respectively. On multivariate analysis, stent dwelling time, stent insertion because of sepsis, and female gender were significantly associated with post-ureteroscopy sepsis in patients with prior stent placement. Patients who undergo ureteroscopy after ureteric stent insertion have a higher risk of postoperative sepsis. Prolonged stent dwelling time, sepsis as an indication for stent insertion, and female gender are independent risk factors. Stent placement should be considered cautiously, and if inserted, ureteroscopy should be performed within 1 month. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

A simple microstructure return model explaining microstructure noise and Epps effects

NASA Astrophysics Data System (ADS)

Saichev, A.; Sornette, D.

2014-01-01

We present a novel simple microstructure model of financial returns that combines (i) the well-known ARFIMA process applied to tick-by-tick returns, (ii) the bid-ask bounce effect, (iii) the fat tail structure of the distribution of returns and (iv) the non-Poissonian statistics of inter-trade intervals. This model allows us to explain both qualitatively and quantitatively important stylized facts observed in the statistics of both microstructure and macrostructure returns, including the short-ranged correlation of returns, the long-ranged correlations of absolute returns, the microstructure noise and Epps effects. According to the microstructure noise effect, volatility is a decreasing function of the time-scale used to estimate it. The Epps effect states that cross correlations between asset returns are increasing functions of the time-scale at which the returns are estimated. The microstructure noise is explained as the result of the negative return correlations inherent in the definition of the bid-ask bounce component (ii). In the presence of a genuine correlation between the returns of two assets, the Epps effect is due to an average statistical overlap of the momentum of the returns of the two assets defined over a finite time-scale in the presence of the long memory process (i).

Educational differences in leisure-time physical inactivity: a descriptive and explanatory study.

PubMed

Droomers, M; Schrijvers, C T; van de Mheen, H; Mackenbach, J P

1998-12-01

In this study we aim to explain educational differences in leisure-time physical inactivity in terms of psychosocial and material factors. Cross-sectional data were obtained from the baseline of the Dutch GLOBE study in 1991, including 2598 men and women, aged 15-74 years. Physical inactivity during leisure time was defined as not participating in any activity, such as sports, gardening, walking or cycling. Psychosocial factors included in the study were coping resources, personality, and stressors. Material factors were financial situation, employment status, and living conditions. Logistic regression models were used to calculate educational differences in physical inactivity. Physical inactivity was more prevalent in lower educational groups. Psychosocial factors related to physical inactivity were locus of control, parochialism, neuroticism, emotional social support, active problem focussing, optimistic and palliative coping styles. Material factors associated with physical inactivity were income, employment status and financial problems. All correlates of physical inactivity were unequally distributed over educational groups, except optimistic and palliative coping. Personality and coping style were the main contributors to the observed educational differences in physical inactivity. That is to say, parochialism, locus of control, neuroticism and active problem focussing explained about half of elevated odds ratios of physical inactivity in the lower educational groups. The material factors, equivalent income and employment status explained about 40% of the elevated odds ratios. Psychosocial and material correlates together reduced the odds ratios of lower educational groups by on average 75%. These results have practical consequences for the design of more effective interventions to promote physical activity. In particular, personality and coping style of risk groups, such as lower educational groups, should be taken into consideration at the future

The Influence of Contextual and Psychosocial Factors on Handwashing.

PubMed

Seimetz, Elisabeth; Boyayo, Anne-Marie; Mosler, Hans-Joachim

2016-06-01

Even though washing hands with soap is among the most effective measures to reduce the risk of infection, handwashing rates in infrastructure-restricted settings remain seriously low. Little is known about how context alone and in interaction with psychosocial factors influence hand hygiene behavior. The aim of this article was to explore how both contextual and psychosocial factors affect handwashing practices. A cross-sectional survey was conducted with 660 caregivers of primary school children in rural Burundi. Hierarchical regression analyses revealed that household wealth, the amount of water per person, and having a designated place for washing hands were contextual factors significantly predicting handwashing frequency, whereas the contextual factors, time spent collecting water and amount of money spent on soap, were not significant predictors. The contextual factors explained about 13% of the variance of reported handwashing frequency. The addition of the psychosocial factors to the regression model resulted in a significant 41% increase of explained variation in handwashing frequency. In this final model, the amount of water was the only contextual factor that remained a significant predictor. The most important predictors were a belief of self-efficacy, planning how, when, and where to wash hands, and always remembering to do so. The findings suggest that contextual constraints might be perceived rather than actual barriers and highlight the role of psychosocial factors in understanding hygiene behaviors. © The American Society of Tropical Medicine and Hygiene.

Can technical factors explain the volume-outcome relationship in gastric bypass surgery?

PubMed

Smith, Mark D; Patterson, Emma; Wahed, Abdus S; Belle, Steven H; Courcoulas, Anita P; Flum, David; Khandelwal, Saurabh; Mitchell, James E; Pomp, Alfons; Pories, Walter J; Wolfe, Bruce

2013-01-01

The existence of a relationship between surgeon volume and patient outcome has been reported for different complex surgical operations. This relationship has also been confirmed for patients undergoing Roux-en-Y gastric bypass (RYGB) in the Longitudinal Assessment of Bariatric Surgery (LABS) study. Despite multiple studies demonstrating volume-outcome relationships, fewer studies investigate the causes of this relationship. The purpose of the present study is to understand possible explanations for the volume-outcome relationship in LABS. LABS includes a 10-center, prospective study examining 30-day outcomes after bariatric surgery. The relationship between surgeon annual RYGB volume and incidence of a composite endpoint (CE) has been published previously. Technical aspects of RYGB surgery were compared between high and low volume surgeons. The previously published model was adjusted for select technical factors. High-volume surgeons (>100 RYGBs/yr) were more likely to perform a linear stapled gastrojejunostomy, use fibrin sealant, and place a drain at the gastrojejunostomy compared with low-volume surgeons (<25 RYGBs/yr), and less likely to perform an intraoperative leak test. After adjusting for the newly identified technical factors, the relative risk of CE was .93 per 10 RYGB/yr increase in volume, compared with .90 for clinical risk adjustment alone. High-volume surgeons exhibited certain differences in technique compared with low-volume surgeons. After adjusting for these differences, the strength of the volume-outcome relationship previously found was reduced only slightly, suggesting that other factors are also involved. Copyright © 2013 American Society for Bariatric Surgery. All rights reserved.

Factors Influencing Cecal Intubation Time during Retrograde Approach Single-Balloon Enteroscopy

PubMed Central

Chen, Peng-Jen; Shih, Yu-Lueng; Huang, Hsin-Hung; Hsieh, Tsai-Yuan

2014-01-01

Background and Aim. The predisposing factors for prolonged cecal intubation time (CIT) during colonoscopy have been well identified. However, the factors influencing CIT during retrograde SBE have not been addressed. The aim of this study was to determine the factors influencing CIT during retrograde SBE. Methods. We investigated patients who underwent retrograde SBE at a medical center from January 2011 to March 2014. The medical charts and SBE reports were reviewed. The patients' characteristics and procedure-associated data were recorded. These data were analyzed with univariate analysis as well as multivariate logistic regression analysis to identify the possible predisposing factors. Results. We enrolled 66 patients into this study. The median CIT was 17.4 minutes. With univariate analysis, there was no statistical difference in age, sex, BMI, or history of abdominal surgery, except for bowel preparation (P = 0.021). Multivariate logistic regression analysis showed that inadequate bowel preparation (odds ratio 30.2, 95% confidence interval 4.63–196.54; P < 0.001) was the independent predisposing factors for prolonged CIT during retrograde SBE. Conclusions. For experienced endoscopist, inadequate bowel preparation was the independent predisposing factor for prolonged CIT during retrograde SBE. PMID:25505904

What explains gender inequalities in HIV/AIDS prevalence in sub-Saharan Africa? Evidence from the demographic and health surveys.

PubMed

Sia, Drissa; Onadja, Yentéma; Hajizadeh, Mohammad; Heymann, S Jody; Brewer, Timothy F; Nandi, Arijit

2016-11-03

Women are disproportionally affected by human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa (SSA). The determinants of gender inequality in HIV/AIDS may vary across countries and require country-specific interventions to address them. This study aimed to identify the socio-demographic and behavioral characteristics underlying gender inequalities in HIV/AIDS in 21 SSA countries. We applied an extension of the Blinder-Oaxaca decomposition approach to data from Demographic and Health Surveys and AIDS Indicator Surveys to quantify the differences in HIV/AIDS prevalence between women and men attributable to socio-demographic factors, sexual behaviours, and awareness of HIV/AIDS. We decomposed gender inequalities into two components: the percentage attributable to different levels of the risk factors between women and men (the "composition effect") and the percentage attributable to risk factors having differential effects on HIV/AIDS prevalence in women and men (the "response effect"). Descriptive analyses showed that the difference between women and men in HIV/AIDS prevalence varied from a low of 0.68 % (P = 0.008) in Liberia to a high of 11.5 % (P < 0.001) in Swaziland. The decomposition analysis showed that 84 % (P < 0.001) and 92 % (P < 0.001) of the higher prevalence of HIV/AIDS among women in Uganda and Ghana, respectively, was explained by the different distributions of HIV/AIDS risk factors, particularly age at first sex between women and men. In the majority of countries, however, observed gender inequalities in HIV/AIDS were chiefly explained by differences in the responses to risk factors; the differential effects of age, marital status and occupation on prevalence of HIV/AIDS for women and men were among the significant contributors to this component. In Cameroon, Guinea, Malawi and Swaziland, a combination of the composition and response effects explained gender inequalities in HIV

Extracting factors for interest rate scenarios

NASA Astrophysics Data System (ADS)

Molgedey, L.; Galic, E.

2001-04-01

Factor based interest rate models are widely used for risk managing purposes, for option pricing and for identifying and capturing yield curve anomalies. The movements of a term structure of interest rates are commonly assumed to be driven by a small number of orthogonal factors such as SHIFT, TWIST and BUTTERFLY (BOW). These factors are usually obtained by a Principal Component Analysis (PCA) of historical bond prices (interest rates). Although PCA diagonalizes the covariance matrix of either the interest rates or the interest rate changes, it does not use both covariance matrices simultaneously. Furthermore higher linear and nonlinear correlations are neglected. These correlations as well as the mean reverting properties of the interest rates become crucial, if one is interested in a longer time horizon (infrequent hedging or trading). We will show that Independent Component Analysis (ICA) is a more appropriate tool than PCA, since ICA uses the covariance matrix of the interest rates as well as the covariance matrix of the interest rate changes simultaneously. Additionally higher linear and nonlinear correlations may be easily incorporated. The resulting factors are uncorrelated for various time delays, approximately independent but nonorthogonal. This is in contrast to the factors obtained from the PCA, which are orthogonal and uncorrelated for identical times only. Although factors from the ICA are nonorthogonal, it is sufficient to consider only a few factors in order to explain most of the variation in the original data. Finally we will present examples that ICA based hedges outperforms PCA based hedges specifically if the portfolio is sensitive to structural changes of the yield curve.

Identifying Nonprovider Factors Affecting Pediatric Emergency Medicine Provider Efficiency.

PubMed

Saleh, Fareed; Breslin, Kristen; Mullan, Paul C; Tillett, Zachary; Chamberlain, James M

2017-10-31

The aim of this study was to create a multivariable model of standardized relative value units per hour by adjusting for nonprovider factors that influence efficiency. We obtained productivity data based on billing records measured in emergency relative value units for (1) both evaluation and management of visits and (2) procedures for 16 pediatric emergency medicine providers with more than 750 hours worked per year. Eligible shifts were in an urban, academic pediatric emergency department (ED) with 2 sites: a tertiary care main campus and a satellite community site. We used multivariable linear regression to adjust for the impact of shift and pediatric ED characteristics on individual-provider efficiency and then removed variables from the model with minimal effect on productivity. There were 2998 eligible shifts for the 16 providers during a 3-year period. The resulting model included 4 variables when looking at both ED sites combined. These variables include the following: (1) number of procedures billed by provider, (2) season of the year, (3) shift start time, and (4) day of week. Results were improved when we separately modeled each ED location. A 3-variable model using procedures billed by provider, shift start time, and season explained 23% of the variation in provider efficiency at the academic ED site. A 3-variable model using procedures billed by provider, patient arrivals per hour, and shift start time explained 45% of the variation in provider efficiency at the satellite ED site. Several nonprovider factors affect provider efficiency. These factors should be considered when designing productivity-based incentives.

Mothering and anxiety: Social support and competence as mitigating factors for first-time mothers.

PubMed

Chavis, Llena

2016-07-01

This study investigated anxiety as a phenomenon distinct from depression and evaluated several variables that influence anxiety in first-time mothers. This explored the relationship between maternal sense of competence (both of mothering and efficacy) and perceived social support (from family, friends, and significant others) and first-time mothers' postpartum anxiety, when depression, socioeconomic status (SES), and marital status were controlled for. The population studied were 86 first-time mothers made up of women with children 24 months or younger in two populations of Kentucky and Michigan. The constructs of maternal sense of competence and perceived social support were found to be significant in explaining first-time mothers' anxiety. The study concluded that a combined association of perceived social support and maternal sense of competence were associated with a 34% (change in R-squared = .339) decrease of a first-time mothers' anxiety. However, not all types of social support, or maternal competence appeared to be equally important with regards to maternal anxiety: social support from friends and family and maternal sense of competence in regard to productivity appeared to be most significant. Lastly, some recommendations for health practitioners who work with mothers are provided.

Meteorological factors and timing of the initiating event of human parturition

NASA Astrophysics Data System (ADS)

Hirsch, Emmet; Lim, Courtney; Dobrez, Deborah; Adams, Marci G.; Noble, William

2011-03-01

The aim of this study was to determine whether meteorological factors are associated with the timing of either onset of labor with intact membranes or rupture of membranes prior to labor—together referred to as `the initiating event' of parturition. All patients delivering at Evanston Hospital after spontaneous labor or rupture of membranes at ≥20 weeks of gestation over a 6-month period were studied. Logistic regression models of the initiating event of parturition using clinical variables (maternal age, gestational age, parity, multiple gestation and intrauterine infection) with and without the addition of meteorological variables (barometric pressure, temperature and humidity) were compared. A total of 1,088 patients met the inclusion criteria. Gestational age, multiple gestation and chorioamnionitis were associated with timing of initiation of parturition ( P < 0.01). The addition of meteorological to clinical variables generated a statistically significant improvement in prediction of the initiating event; however, the magnitude of this improvement was small (less than 2% difference in receiver-operating characteristic score). These observations held regardless of parity, fetal number and gestational age. Meteorological factors are associated with the timing of parturition, but the magnitude of this association is small.

Flynn effects on sub-factors of episodic and semantic memory: parallel gains over time and the same set of determining factors.

PubMed

Rönnlund, Michael; Nilsson, Lars-Göran

2009-09-01

The study examined the extent to which time-related gains in cognitive performance, so-called Flynn effects, generalize across sub-factors of episodic memory (recall and recognition) and semantic memory (knowledge and fluency). We conducted time-sequential analyses of data drawn from the Betula prospective cohort study, involving four age-matched samples (35-80 years; N=2996) tested on the same battery of memory tasks on either of four occasions (1989, 1995, 1999, and 2004). The results demonstrate substantial time-related improvements on recall and recognition as well as on fluency and knowledge, with a trend of larger gains on semantic as compared with episodic memory [Rönnlund, M., & Nilsson, L. -G. (2008). The magnitude, generality, and determinants of Flynn effects on forms of declarative memory: Time-sequential analyses of data from a Swedish cohort study. Intelligence], but highly similar gains across the sub-factors. Finally, the association with markers of environmental change was similar, with evidence that historical increases in quantity of schooling was a main driving force behind the gains, both on the episodic and semantic sub-factors. The results obtained are discussed in terms of brain regions involved.

Prevalence, pathophysiological mechanisms and factors affecting urolithiasis.

PubMed

Khan, Aslam

2018-05-01

The formation of urinary stone, urolithiasis, is one the oldest known disease affecting human throughout different civilizations and times. The exact pathophysiological mechanism of urolithiasis is not yet clear, as these calculi are of various types and too complex for simple understanding. A single theory cannot explain its formation; therefore, different theories are presented in various times for its explanation like free particle, fixed particle, Randall's plaque theory. In addition, various factors and components are identified that play an important role in the formation of these urinary calculi. In this review, composition of kidney stones, its prevalence/incidence, explanation of pathophysiological mechanisms and role of various factors; urinary pH, uric acid, parathyroid hormone, citrate, oxalate, calcium and macromolecules; osteopontin, matrix Gla protein, kidney injury molecules, urinary prothrombin fragment-1, Tamm-Horsfall protein, inter-α-inhibitors, have been discussed in detail.

Factors influencing nursing time spent on administration of medication in an Australian residential aged care home.

PubMed

Qian, Siyu; Yu, Ping; Hailey, David M; Wang, Ning

2016-04-01

To examine nursing time spent on administration of medications in a residential aged care (RAC) home, and to determine factors that influence the time to medicate a resident. Information on nursing time spent on medication administration is useful for planning and implementation of nursing resources. Nurses were observed over 12 morning medication rounds using a time-motion observational method and field notes, at two high-care units in an Australian RAC home. Nurses spent between 2.5 and 4.5 hours in a medication round. Administration of medication averaged 200 seconds per resident. Four factors had significant impact on medication time: number of types of medication, number of tablets taken by a resident, methods used by a nurse to prepare tablets and methods to provide tablets. Administration of medication consumed a substantial, though variable amount of time in the RAC home. Nursing managers need to consider the factors that influenced the nursing time required for the administration of medication in their estimation of nursing workload and required resources. To ensure safe medication administration for older people, managers should regularly assess the changes in the factors influencing nursing time on the administration of medication when estimating nursing workload and required resources. © 2015 John Wiley & Sons Ltd.

Calculations of steady and transient channel flows with a time-accurate L-U factorization scheme

NASA Technical Reports Server (NTRS)

Kim, S.-W.

1991-01-01

Calculations of steady and unsteady, transonic, turbulent channel flows with a time accurate, lower-upper (L-U) factorization scheme are presented. The L-U factorization scheme is formally second-order accurate in time and space, and it is an extension of the steady state flow solver (RPLUS) used extensively to solve compressible flows. A time discretization method and the implementation of a consistent boundary condition specific to the L-U factorization scheme are also presented. The turbulence is described by the Baldwin-Lomax algebraic turbulence model. The present L-U scheme yields stable numerical results with the use of much smaller artificial dissipations than those used in the previous steady flow solver for steady and unsteady channel flows. The capability to solve time dependent flows is shown by solving very weakly excited and strongly excited, forced oscillatory, channel flows.

Explaining negative refraction without negative refractive indices.

PubMed

Talalai, Gregory A; Garner, Timothy J; Weiss, Steven J

2018-03-01

Negative refraction through a triangular prism may be explained without assigning a negative refractive index to the prism by using array theory. For the case of a beam incident upon the wedge, the array theory accurately predicts the beam transmission angle through the prism and provides an estimate of the frequency interval at which negative refraction occurs. The hypotenuse of the prism has a staircase shape because it is built of cubic unit cells. The large phase delay imparted by each unit cell, combined with the staircase shape of the hypotenuse, creates the necessary conditions for negative refraction. Full-wave simulations using the finite-difference time-domain method show that array theory accurately predicts the beam transmission angle.

[Impact factors and publication time spans of child and adolescent psychiatry journals].

PubMed

Haberhausen, Michael; Bachmann, Christian

2009-01-01

The impact factor (IF) of a scientific journal plays a central role in a scientist's decision where to publish his or her research results. Authors also show interest in the publication time span (time span between the submission and the online or print publication of a article). This paper presents an overview of the IF and editorial time spans of German and international child and adolescent psychiatric journals and compares them to those of journals of adult psychiatry. The authors first conducted a data bank search at the Journal Citation Reports, concerning IF and IF-development for key journals of child and adolescent psychiatry from 2002-2007. They then manually analyzed pertinent child and adolescent journals regarding the time span for publications in the year 2007. To date, nine child and adolescent psychiatric journals exist, whereof eight present with an impact factor. The IF ranges from 0.419 (praxis der Kinderpsychologie und Kinderpsychiatrie) to 4.655 (Journal of the American Academy of Child and Adolescent Psychiatry). The editorial handling time ranges between 5.4 and 13.2 months. Even though this academic discipline is "small", child and adolescent psychiatry disposes of international journals presenting with competitive IFs. Both German journals show a low IF. The editorial handling times were reasonable, but could be further reduced by offering prior online publication.

Effects of state and trait factors on nightmare frequency.

PubMed

Schredl, Michael

2003-10-01

In a new approach, this study compared the effects of trait and state factors on nightmare frequency in a non-clinical sample. Although neuroticism and boundary thinness were related to nightmare frequency, regression analyses indicated that the trait measures did not add to the variance explained by the state measures. This finding supports the so-called continuity hypothesis of dreaming, i. e., nightmares reflect negative waking-life experiences. Second, the moderate relationship between nightmare frequency and poor sleep quality was partly explained by the day-time measures of neuroticism and stress, but it can be assumed that nightmares are an independent factor contributing to complaints of insomnia. Longitudinal studies measuring nightmare frequency and stress on a daily basis will shed light on the temporal relationship between daytime measures and the occurrence of nightmares. It will be also very interesting to study the relationship between stress and nightmare frequency in a sample who have undergone cognitive-behavioral treatment for nightmares.

A common stochastic accumulator with effector-dependent noise can explain eye-hand coordination

PubMed Central

Gopal, Atul; Viswanathan, Pooja

2015-01-01

The computational architecture that enables the flexible coupling between otherwise independent eye and hand effector systems is not understood. By using a drift diffusion framework, in which variability of the reaction time (RT) distribution scales with mean RT, we tested the ability of a common stochastic accumulator to explain eye-hand coordination. Using a combination of behavior, computational modeling and electromyography, we show how a single stochastic accumulator to threshold, followed by noisy effector-dependent delays, explains eye-hand RT distributions and their correlation, while an alternate independent, interactive eye and hand accumulator model does not. Interestingly, the common accumulator model did not explain the RT distributions of the same subjects when they made eye and hand movements in isolation. Taken together, these data suggest that a dedicated circuit underlies coordinated eye-hand planning. PMID:25568161

Social nature of eating could explain missing link between food insecurity and childhood obesity.

PubMed

Mata, Jutta; Dallacker, Mattea; Hertwig, Ralph

2017-01-01

We suggest that social factors are key to explain the missing link between food insecurity and obesity in children. Parents and public institutions are children's nutritional gatekeepers. They protect children from food insecurity by trimming down their consumption or by institutional support. To gauge children's food insecurity, evaluations across the different nutritional gatekeepers need to be integrated.

Rising Educational Gradients in Mortality: The Role of Behavioral Risk Factors

PubMed Central

Cutler, David M; Meara, Ellen; Richards-Shubik, Seth; Ruhm, Christopher J

2013-01-01

The long-standing inverse relationship between education and mortality strengthened substantially at the end of the 20th century. This paper examines the reasons for this increase. We show that behavioral risk factors are not of primary importance. Smoking declined more for the better educated, but not enough to explain the trend. Obesity rose at similar rates across education groups, and control of blood pressure and cholesterol increased fairly uniformly as well. Rather, our results show that the mortality returns to risk factors, and conditional on risk factors, the return to education, have grown over time. PMID:21925754

Motivation and Perception of Tourists as Push and Pull Factors to Visit National Park

NASA Astrophysics Data System (ADS)

Said, Jumrin; Maryono

2018-02-01

Push-pull theoretical framework is a popular theory to explain the reason why the tourists decide to visit the destination rather than other place, the kind of experience they want to get and the type of activity they want to do. In this paper, it is explained the motivation as push factors and the perception as pull factors of the tourist in deciding the destination based on previous literature and research using descriptive method. The framework asumed that tourists are motivated to fulfill their needs, including to reduce the psychological imbalance and to gain recognition of social status. National Park is one of destination based on nature or commonly knowns as ecotourism. In choosing the destination, the tourists tend to classify their alternative choice based on several criteria, such as the domination perception of tourist from one destination (pull factor), self motivation (push factor) and the available time and money (situational constraints).

Time Factor in the Theory of Anthropogenic Risk Prediction in Complex Dynamic Systems

NASA Astrophysics Data System (ADS)

Ostreikovsky, V. A.; Shevchenko, Ye N.; Yurkov, N. K.; Kochegarov, I. I.; Grishko, A. K.

2018-01-01

The article overviews the anthropogenic risk models that take into consideration the development of different factors in time that influence the complex system. Three classes of mathematical models have been analyzed for the use in assessing the anthropogenic risk of complex dynamic systems. These models take into consideration time factor in determining the prospect of safety change of critical systems. The originality of the study is in the analysis of five time postulates in the theory of anthropogenic risk and the safety of highly important objects. It has to be stressed that the given postulates are still rarely used in practical assessment of equipment service life of critically important systems. That is why, the results of study presented in the article can be used in safety engineering and analysis of critically important complex technical systems.

Quantifying and modeling long-range cross correlations in multiple time series with applications to world stock indices

NASA Astrophysics Data System (ADS)

Wang, Duan; Podobnik, Boris; Horvatić, Davor; Stanley, H. Eugene

2011-04-01

We propose a modified time lag random matrix theory in order to study time-lag cross correlations in multiple time series. We apply the method to 48 world indices, one for each of 48 different countries. We find long-range power-law cross correlations in the absolute values of returns that quantify risk, and find that they decay much more slowly than cross correlations between the returns. The magnitude of the cross correlations constitutes “bad news” for international investment managers who may believe that risk is reduced by diversifying across countries. We find that when a market shock is transmitted around the world, the risk decays very slowly. We explain these time-lag cross correlations by introducing a global factor model (GFM) in which all index returns fluctuate in response to a single global factor. For each pair of individual time series of returns, the cross correlations between returns (or magnitudes) can be modeled with the autocorrelations of the global factor returns (or magnitudes). We estimate the global factor using principal component analysis, which minimizes the variance of the residuals after removing the global trend. Using random matrix theory, a significant fraction of the world index cross correlations can be explained by the global factor, which supports the utility of the GFM. We demonstrate applications of the GFM in forecasting risks at the world level, and in finding uncorrelated individual indices. We find ten indices that are practically uncorrelated with the global factor and with the remainder of the world indices, which is relevant information for world managers in reducing their portfolio risk. Finally, we argue that this general method can be applied to a wide range of phenomena in which time series are measured, ranging from seismology and physiology to atmospheric geophysics.

Quantifying and modeling long-range cross correlations in multiple time series with applications to world stock indices.

PubMed

Wang, Duan; Podobnik, Boris; Horvatić, Davor; Stanley, H Eugene

2011-04-01

We propose a modified time lag random matrix theory in order to study time-lag cross correlations in multiple time series. We apply the method to 48 world indices, one for each of 48 different countries. We find long-range power-law cross correlations in the absolute values of returns that quantify risk, and find that they decay much more slowly than cross correlations between the returns. The magnitude of the cross correlations constitutes "bad news" for international investment managers who may believe that risk is reduced by diversifying across countries. We find that when a market shock is transmitted around the world, the risk decays very slowly. We explain these time-lag cross correlations by introducing a global factor model (GFM) in which all index returns fluctuate in response to a single global factor. For each pair of individual time series of returns, the cross correlations between returns (or magnitudes) can be modeled with the autocorrelations of the global factor returns (or magnitudes). We estimate the global factor using principal component analysis, which minimizes the variance of the residuals after removing the global trend. Using random matrix theory, a significant fraction of the world index cross correlations can be explained by the global factor, which supports the utility of the GFM. We demonstrate applications of the GFM in forecasting risks at the world level, and in finding uncorrelated individual indices. We find ten indices that are practically uncorrelated with the global factor and with the remainder of the world indices, which is relevant information for world managers in reducing their portfolio risk. Finally, we argue that this general method can be applied to a wide range of phenomena in which time series are measured, ranging from seismology and physiology to atmospheric geophysics.

Do repeated risk factor measurements influence the impact of education on cardiovascular mortality?

PubMed

Ariansen, Inger; Graff-Iversen, Sidsel; Stigum, Hein; Strand, Bjørn Heine; Wills, Andrew K; Næss, Øyvind

2015-12-01

It has been questioned if the excess cardiovascular disease (CVD) mortality by lower educational level can be fully explained by conventional modifiable CVD risk factors. Our objective was to examine whether repeated measures over time of risk factors (smoking, physical inactivity, blood pressure, total cholesterol and body mass index) explain more of the socioeconomic gradient in CVD mortality than if they are measured only once. A cohort of 34 884 men and women attended all three screenings (1974-1978, 1977-1983 and 1985-1988) in the Norwegian Counties Study and were followed for CVD mortality through 2009 by linkage to the Norwegian Cause of Death Registry. Age-adjusted and sex-adjusted HR of CVD mortality was 2.32 (95% CI 1.93 to 2.80) for basic relative to tertiary educated individuals. The HR was attenuated by 48% (HR 1.54 (1.28 to 1.87)) when adjusted for CVD risk factors measured at baseline and by 56% (HR 1.45 (1.20 to 1.75)) when two repeated measurements ascertained 5 years apart were added to the model. Similarly, absolute risk difference in CVD mortality by education was attenuated by 62% when adjusted for baseline and by 72% when adjusted for repeated measurements of risk factors. In this cohort, repeated measurements of risk factors seemed to explain more of the educational gradient in CVD mortality. This suggests that a substantial part of the excess CVD mortality among those with lower education might be explained by conventional risk factors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Estimating and explaining the effect of education and income on head and neck cancer risk: INHANCE consortium pooled analysis of 31 case-control studies from 27 countries

PubMed Central

Conway, David I.; Brenner, Darren R.; McMahon, Alex D.; Macpherson, Lorna M.D.; Agudo, Antonio; Ahrens, Wolfgang; Bosetti, Cristina; Brenner, Hermann; Castellsague, Xavier; Chen, Chu; Curado, Maria Paula; Curioni, Otávio A.; Maso, Luigino Dal; Daudt, Alexander W.; de Gois Filho, José F.; D'Souza, Gypsyamber; Edefonti, Valeria; Fabianova, Eleonora; Fernandez, Leticia; Franceschi, Silvia; Gillison, Maura; Hayes, Richard B.; Healy, Claire M.; Herrero, Rolando; Holcatova, Ivana; Jayaprakash, Vijayvel; Kelsey, Karl; Kjaerheim, Kristina; Koifman, Sergio; La Vecchia, Carlo; Lagiou, Pagona; Lazarus, Philip; Levi, Fabio; Lissowska, Jolanta; Luce, Daniele; Macfarlane, Tatiana V.; Mates, Dana; Matos, Elena; McClean, Michael; Menezes, Ana M; Menvielle, Gwenn; Merletti, Franco; Morgenstern, Hal; Moysich, Kirsten; Müller, Heiko; Muscat, Joshua; Olshan, Andrew F.; Purdue, Mark P.; Ramroth, Heribert; Richiardi, Lorenzo; Rudnai, Peter; Schantz, Stimson; Schwartz, Stephen M.; Shangina, Oxana; Simonato, Lorenzo; Smith, Elaine; Stucker, Isabelle; Sturgis, Erich M.; Szeszenia-Dabrowska, Neonila; Talamini, Renato; Thomson, Peter; Vaughan, Thomas L.; Wei, Qingyi; Winn, Deborah M.; Wunsch-Filho, Victor; Yu, Guo-Pei; Zhang, Zuo-Feng; Zheng, Tongzhang; Znaor, Ariana; Boffetta, Paolo; Chuang, Shu-Chun; Ghodrat, Marianoosh; Lee, Yuan-Chin Amy; Hashibe, Mia; Brennan, Paul

2015-01-01

Low socioeconomic status has been reported to be associated with head and neck cancer risk. However, previous studies have been too small to examine the associations by cancer subsite, age, sex, global region and calendar time and to explain the association in terms of behavioral risk factors. Individual participant data of 23,964 cases with head and neck cancer and 31,954 controls from 31 studies in 27 countries pooled with random effects models. Overall, low education was associated with an increased risk of head and neck cancer (OR = 2.50; 95% CI = 2.02 – 3.09). Overall one-third of the increased risk was not explained by differences in the distribution of cigarette smoking and alcohol behaviors; and it remained elevated among never users of tobacco and nondrinkers (OR = 1.61; 95% CI = 1.13 – 2.31). More of the estimated education effect was not explained by cigarette smoking and alcohol behaviors: in women than in men, in older than younger groups, in the oropharynx than in other sites, in South/Central America than in Europe/North America and was strongest in countries with greater income inequality. Similar findings were observed for the estimated effect of low versus high household income. The lowest levels of income and educational attainment were associated with more than 2-fold increased risk of head and neck cancer, which is not entirely explained by differences in the distributions of behavioral risk factors for these cancers and which varies across cancer sites, sexes, countries and country income inequality levels. PMID:24996155

Examination of Factors Explaining Coaching Strategy and Training Methodology as Correlates of Potential Doping Behavior in High-Level Swimming.

PubMed

Liposek, Silvester; Zenic, Natasa; Saavedra, Jose M; Sekulic, Damir; Rodek, Jelena; Marinsek, Miha; Sajber, Dorica

2018-03-01

Although coaching is considered an important determinant of athletes' potential doping behavior (PDB), there is an evident lack of studies that have examined coaching-strategy-and-training-methodology (CS&TM) in relation to PDB. This study was aimed to identify the specific associations that may exist between CS&TM -factors and other factors, and PDB in high-level swimming. The sample comprised 94 swimmers (35 females; 19.7 ± 2.3 years of age) and consisted of swimmers older than 18 years who participated in the 2017 National Championship. Variables were collected by previously validated questionnaires, with the addition of questions where athletes were asked about CS&TM to which they had been exposed. Multinomial logistic regression was applied for the criterion PDB (Negative PDB - Neutral PDB - Positive PDB). The higher risk for positive-PDB was found in males (OR: 6.58; 95%CI: 1.01-9.12); therefore, all regressions were adjusted for gender. Those swimmers who achieved better competitive result were less prone to neutral-PDB (0.41; 0.17-0.98). The positive-PDB was evidenced in those swimmers who perceived that their training was monotonous and lacked diversity (1.82; 1.41-5.11), and who were involved in training which was mostly oriented toward volume (1.76; 1.11-7.12). The lower likelihood of positive-PDB is found in those who replied that technique is practiced frequently (0.12; 0.01-0.81), those who replied that coach regularly provided the attention to explain the training aims (0.21; 0.04-0.81), and that coach frequently reviewed and discussed the quality of execution of specific tasks (0.41; 0.02-0.81). The findings on the relationships between the studied variables and PDB should be incorporated into targeted anti-doping efforts in swimming. Further studies examining sport-specific variables of CS&TM in younger swimmers and other sports are warranted.

Impact of Lead Time and Safety Factor in Mixed Inventory Models with Backorder Discounts

NASA Astrophysics Data System (ADS)

Lo, Ming-Cheng; Chao-Hsien Pan, Jason; Lin, Kai-Cing; Hsu, Jia-Wei

This study investigates the impact of safety factor on the continuous review inventory model involving controllable lead time with mixture of backorder discount and partial lost sales. The objective is to minimize the expected total annual cost with respect to order quantity, backorder price discount, safety factor and lead time. A model with normal demand is also discussed. Numerical examples are presented to illustrate the procedures of the algorithms and the effects of parameters on the result of the proposed models are analyzed.

Heavy fermion behavior explained by bosons

NASA Technical Reports Server (NTRS)

Kallio, A.; Poykko, S.; Apaja, V.

1995-01-01

Conventional heavy fermion (HF) theories require existence of massive fermions. We show that heavy fermion phenomena can also be simply explained by existence of bosons with moderate mass but temperature dependent concentration below the formation temperature T(sub B), which in turn is close to room temperature. The bosons B(++) are proposed to be in chemical equilibrium with a system of holes h(+): B(++) = h(+) + h(+). This equilibrium is governed by a boson breaking function f(T), which determines the decreasing boson density and the increasing fermion density with increasing temperature. Since HF-compounds are hybridized from minimum two elements, we assume in addition existence of another fermion component h(sub s)(+) with temperature independent density. This spectator component is thought to be the main agent in binding the bosons in analogy with electronic or muonic molecules. Using a linear boson breaking function we can explain temperature dependence of the giant linear specific heat coefficient gamma(T) coming essentially from bosons. The maxima in resistivity, Hall coefficient, and susceptibility are explained by boson localization effects due to the Wigner crystallization. The antiferromagnetic transitions in turn are explained by similar localization of the pairing fermion system when their density n(sub h)(T(sub FL)) becomes lower than n(sub WC), the critical density of Wigner crystallization. The model applies irrespective whether a compound is superconducting or not. The same model explains the occurrence of low temperature antiferromagnetism also in high-T(sub c) superconductors. The double transition in UPt3 is proposed to be due to the transition of the pairing fermion liquid from spin polarized to unpolarized state.

Does boldness explain vulnerability to angling in Eurasian perch Perca fluviatilis?

PubMed

Vainikka, Anssi; Tammela, Ilkka; Hyvärinen, Pekka

2016-04-01

Consistent individual differences (CIDs) in behavior are of interest to both basic and applied research, because any selection acting on them could induce evolution of animal behavior. It has been suggested that CIDs in the behavior of fish might explain individual differences in vulnerability to fishing. If so, fishing could impose selection on fish behavior. In this study, we assessed boldness-indicating behaviors of Eurasian perch Perca fluviatilis using individually conducted experiments measuring the time taken to explore a novel arena containing predator (burbot, Lota lota ) cues. We studied if individual differences in boldness would explain vulnerability of individually tagged perch to experimental angling in outdoor ponds, or if fishing would impose selection on boldness-indicating behavior. Perch expressed repeatable individual differences in boldness-indicating behavior but the individual boldness-score (the first principal component) obtained using principal component analysis combining all the measured behavioral responses did not explain vulnerability to experimental angling. Instead, large body size appeared as the only statistically significant predictor of capture probability. Our results suggest that angling is selective for large size, but not always selective for high boldness.

Does boldness explain vulnerability to angling in Eurasian perch Perca fluviatilis?

PubMed Central

Vainikka, Anssi; Tammela, Ilkka; Hyvärinen, Pekka

2016-01-01

Abstract Consistent individual differences (CIDs) in behavior are of interest to both basic and applied research, because any selection acting on them could induce evolution of animal behavior. It has been suggested that CIDs in the behavior of fish might explain individual differences in vulnerability to fishing. If so, fishing could impose selection on fish behavior. In this study, we assessed boldness-indicating behaviors of Eurasian perch Perca fluviatilis using individually conducted experiments measuring the time taken to explore a novel arena containing predator (burbot, Lota lota) cues. We studied if individual differences in boldness would explain vulnerability of individually tagged perch to experimental angling in outdoor ponds, or if fishing would impose selection on boldness-indicating behavior. Perch expressed repeatable individual differences in boldness-indicating behavior but the individual boldness-score (the first principal component) obtained using principal component analysis combining all the measured behavioral responses did not explain vulnerability to experimental angling. Instead, large body size appeared as the only statistically significant predictor of capture probability. Our results suggest that angling is selective for large size, but not always selective for high boldness. PMID:29491897

Factors associated with trends in infant and child mortality in developing countries during the 1990s.

PubMed Central

Rutstein, S. O.

2000-01-01

The 1990s have seen a remarkable decrease in mortality among infants and children in most developing countries. In some countries, particularly in sub-Saharan Africa, these declines in mortality among children have slowed and are now increasing again. Internationally comparable data derived from survey programmes, such as the Demographic and Health Survey (DHS) programme, are available both to document the changes that have occurred in mortality and to provide insight into some of the factors that may explain these trends in mortality. The factors found in repeated DHS programmes that explain these trends fall into five categories: fertility behaviour; nutritional status, breastfeeding, and infant feeding; the use of health services by mothers and for children; environmental health conditions; and socioeconomic status. Both simple analyses and multivariate analyses of changes in these factors between surveys indicate that all factors affected the mortality trends. However, to explain trends in mortality, the variables themselves had to have changed over time. During the 1990s fertility behaviour, breastfeeding, and infant feeding have changed less than other factors and so would seem to have played a smaller role in mortality trends. This study confirms that trends in mortality during the 1990s were related to more than just a handful of variables. It would, therefore, be a mistake to concentrate policy actions on one or a few of these while forsaking others. Countries with the largest decreases in mortality have had substantial improvements in most of the factors that might be used to explain these changes. In some countries mortality has risen. In part these increases can be explained by the factors included in this study, such as deterioration in seeking medical care for children with fever. Other factors that were not measured, such as the increasing resistance of malaria to drug treatment and the increased prevalence of parental HIV/AIDS, may be contributing

Factors influencing the latency of simple reaction time

PubMed Central

Woods, David L.; Wyma, John M.; Yund, E. William; Herron, Timothy J.; Reed, Bruce

2015-01-01

Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output. PMID:25859198

Identification of regional activation by factorization of high-density surface EMG signals: A comparison of Principal Component Analysis and Non-negative Matrix factorization.

PubMed

Gallina, Alessio; Garland, S Jayne; Wakeling, James M

2018-05-22

In this study, we investigated whether principal component analysis (PCA) and non-negative matrix factorization (NMF) perform similarly for the identification of regional activation within the human vastus medialis. EMG signals from 64 locations over the VM were collected from twelve participants while performing a low-force isometric knee extension. The envelope of the EMG signal of each channel was calculated by low-pass filtering (8 Hz) the monopolar EMG signal after rectification. The data matrix was factorized using PCA and NMF, and up to 5 factors were considered for each algorithm. Association between explained variance, spatial weights and temporal scores between the two algorithms were compared using Pearson correlation. For both PCA and NMF, a single factor explained approximately 70% of the variance of the signal, while two and three factors explained just over 85% or 90%. The variance explained by PCA and NMF was highly comparable (R > 0.99). Spatial weights and temporal scores extracted with non-negative reconstruction of PCA and NMF were highly associated (all p < 0.001, mean R > 0.97). Regional VM activation can be identified using high-density surface EMG and factorization algorithms. Regional activation explains up to 30% of the variance of the signal, as identified through both PCA and NMF. Copyright © 2018 Elsevier Ltd. All rights reserved.

Climate variation explains a third of global crop yield variability

PubMed Central

Ray, Deepak K.; Gerber, James S.; MacDonald, Graham K.; West, Paul C.

2015-01-01

Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32–39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability. PMID:25609225

Explaining feast or famine in randomized field trials. Medical science and criminology compared.

PubMed

Shepherd, Jonathan P

2003-06-01

A feast of randomized controlled trials (RCTs) in medical science and comparative famine in criminology can be explained in terms of cultural and structural factors. Of central importance is the context in which the evaluation of interventions is done and the difference in status of situational research in the two disciplines. Evaluation of medical interventions has traditionally been led by practitioner (clinical) academics. This is not the case in criminal justice, where theory has had higher status than intervention research. Medical science has advanced in, or closely associated with, university teaching hospitals, but links between criminology and criminal justice services are far more tenuous. The late development of situational crime prevention seems extraordinary from a medical perspective, as does the absence of university police schools in the United Kingdom and elsewhere. These structural and cultural factors explain concentration of expectation, resource, and RCT productivity in medical science. The Campbell Collaboration and the Academy of Experimental Criminology are forces which are reducing this polarization of feast and famine in RCTs. But unless scientific criminology is embedded in university schools which are responsible for the education and training of law, probation, and police practitioners, convergence in terms of RCTs and implementation of findings in practice seems unlikely.

Factors Contributing to Single- and Dual-Task Timed "Up & Go" Test Performance in Middle-Aged and Older Adults Who Are Active and Dwell in the Community.

PubMed

Chen, Hui-Ya; Tang, Pei-Fang

2016-03-01

Dual-task Timed "Up & Go" (TUG) tests are likely to have applications different from those of a single-task TUG test and may have different contributing factors. The purpose of this study was to compare factors contributing to performance on single- and dual-task TUG tests. This investigation was a cross-sectional study. Sixty-four adults who were more than 50 years of age and dwelled in the community were recruited. Interviews and physical examinations were performed to identify potential contributors to TUG test performance. The time to complete the single-task TUG test (TUGsingle) or the dual-task TUG test, which consisted of completing the TUG test while performing a serial subtraction task (TUGcognitive) or while carrying water (TUGmanual), was measured. Age, hip extensor strength, walking speed, general mental function, and Stroop scores for word and color were significantly associated with performance on all TUG tests. Hierarchical multiple regression models, without the input of walking speed, revealed different independent factors contributing to TUGsingle performance (Mini-Mental Status Examination score, β=-0.32), TUGmanual performance (age, β=0.35), and TUGcognitive performance (Stroop word score, β=-0.40; Mini-Mental Status Examination score, β=-0.31). At least 40% of the variance in the performance on the 3 TUG tests was not explained by common clinical measures, even when the factor of walking speed was considered. However, this study successfully identified some important factors contributing to performance on different TUG tests, and other studies have reported similar findings for single-task TUG test and dual-task gait performance. Although the TUGsingle and the TUGcognitive shared general mental function as a common factor, the TUGmanual was uniquely influenced by age and the TUGcognitive was uniquely influenced by focused attention. These results suggest that both common and unique factors contribute to performance on single- and dual

The Tennessee study: factors affecting treatment outcome and healing time following nonsurgical root canal treatment.

PubMed

Azim, A A; Griggs, J A; Huang, G T-J

2016-01-01

To determine factors that may influence treatment outcome and healing time following root canal treatment. Root filled and restored teeth by pre-doctoral students were included in this study. Teeth/roots were followed-up regularly, and treatment outcome was evaluated at every follow-up appointment (healed, healing, uncertain or unsatisfactory). Host (age, immune condition, pulp/periapical diagnosis, tooth/root type, location and anatomy) and treatment factors (master apical file size, apical extension, voids and density of root filling) were recorded from patient dental records. Univariate, bivariate and multivariate analyses were performed to determine the impact of the factors on treatment outcomes and healing times. A total of 422 roots from 291 teeth met the inclusion criteria with a mean follow-up period of 2 years. The preoperative pulp condition, procedural errors during treatment, apical extension and density of root fillings significantly affected the treatment outcome. The average time required for a periapical lesion to heal was 11.78 months. The healing time increased in patients with compromised healing, patients older than 40 years, roots with Weine type II root canal systems, root canal systems prepared to a master apical file size <35, and roots with overextended fillings (P < 0.1). Multiple host and treatment factors affected the healing time and outcome of root canal treatment. Follow-up protocols should consider these factors before concluding the treatment outcome: patient's age, immune condition, as well as roots with overextended fillings, root canal systems with smaller apical preparations (size <35) or roots with complex canal systems. Intervention may be recommended if the treatment quality was inadequate or if patients became symptomatic. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Methodological development for selection of significant predictors explaining fatal road accidents.

PubMed

Dadashova, Bahar; Arenas-Ramírez, Blanca; Mira-McWilliams, José; Aparicio-Izquierdo, Francisco

2016-05-01

Identification of the most relevant factors for explaining road accident occurrence is an important issue in road safety research, particularly for future decision-making processes in transport policy. However model selection for this particular purpose is still an ongoing research. In this paper we propose a methodological development for model selection which addresses both explanatory variable and adequate model selection issues. A variable selection procedure, TIM (two-input model) method is carried out by combining neural network design and statistical approaches. The error structure of the fitted model is assumed to follow an autoregressive process. All models are estimated using Markov Chain Monte Carlo method where the model parameters are assigned non-informative prior distributions. The final model is built using the results of the variable selection. For the application of the proposed methodology the number of fatal accidents in Spain during 2000-2011 was used. This indicator has experienced the maximum reduction internationally during the indicated years thus making it an interesting time series from a road safety policy perspective. Hence the identification of the variables that have affected this reduction is of particular interest for future decision making. The results of the variable selection process show that the selected variables are main subjects of road safety policy measures. Published by Elsevier Ltd.

Time-dependent analysis of incidence, risk factors and clinical significance of pneumothorax after percutaneous lung biopsy.

PubMed

Lim, Woo Hyeon; Park, Chang Min; Yoon, Soon Ho; Lim, Hyun-Ju; Hwang, Eui Jin; Lee, Jong Hyuk; Goo, Jin Mo

2018-03-01

To evaluate the time-dependent incidence, risk factors and clinical significance of percutaneous lung biopsy (PLB)-related pneumothorax. From January 2012-November 2015, 3,251 patients underwent 3,354 cone-beam CT-guided PLBs for lung lesions. Cox, logistic and linear regression analyses were performed to identify time-dependent risk factors of PLB-related pneumothorax, risk factors of drainage catheter insertion and those of prolonged catheter placement, respectively. Pneumothorax occurred in 915/3,354 PLBs (27.3 %), with 230/915 (25.1 %) occurring during follow-ups. Risk factors for earlier occurrence of PLB-related pneumothorax include emphysema (HR=1.624), smaller target (HR=0.922), deeper location (HR=1.175) and longer puncture time (HR=1.036), while haemoptysis (HR=0.503) showed a protective effect against earlier development of pneumothorax. Seventy-five cases (8.2 %) underwent chest catheter placement. Mean duration of catheter placement was 3.2±2.0 days. Emphysema (odds ratio [OR]=2.400) and longer puncture time (OR=1.053) were assessed as significant risk factors for catheter insertion, and older age (parameter estimate=1.014) was a predictive factor for prolonged catheter placement. PLB-related pneumothorax occurred in 27.3 %, of which 25.1 % developed during follow-ups. Smaller target size, emphysema, deeply-located lesions were significant risk factors of PLB-related pneumothorax. Emphysema and older age were related to drainage catheter insertion and prolonged catheter placement, respectively. • One-fourth of percutaneous lung biopsy (PLB)-related pneumothorax occurs during follow-up. • Smaller, deeply-located target and emphysema lead to early occurrence of pneumothorax. • Emphysema is related to drainage catheter insertion for PLB-related pneumothorax. • Older age may lead to prolonged catheter placement for PLB-related pneumothorax. • Tailored management can be possible with time-dependent information of PLB-related pneumothorax.

Microeconomic principles explain an optimal genome size in bacteria.

PubMed

Ranea, Juan A G; Grant, Alastair; Thornton, Janet M; Orengo, Christine A

2005-01-01

Bacteria can clearly enhance their survival by expanding their genetic repertoire. However, the tight packing of the bacterial genome and the fact that the most evolved species do not necessarily have the biggest genomes suggest there are other evolutionary factors limiting their genome expansion. To clarify these restrictions on size, we studied those protein families contributing most significantly to bacterial-genome complexity. We found that all bacteria apply the same basic and ancestral 'molecular technology' to optimize their reproductive efficiency. The same microeconomics principles that define the optimum size in a factory can also explain the existence of a statistical optimum in bacterial genome size. This optimum is reached when the bacterial genome obtains the maximum metabolic complexity (revenue) for minimal regulatory genes (logistic cost).

The role of self-efficacy and motivation to explain the effect of motivational interviewing time on changes in risky sexual behavior among people living with HIV: a mediation analysis.

PubMed

Chariyeva, Zulfiya; Golin, Carol E; Earp, Jo Anne; Maman, Suzanne; Suchindran, Chirayath; Zimmer, Catherine

2013-02-01

Little is known about the amount of Motivational Interviewing (MI) needed to reduce risky sexual behavior among People Living with HIV/AIDS (PLWHA) or the roles self-efficacy and motivation to practice safer sex play. Among 183 PLWHA who received safer sex MI and were surveyed every 4 months over a 12 month period, we used hierarchical negative binomial regression models to examine the association between amount of counseling time and sexual risk behavior. We performed mediation analysis to evaluate whether changes in self-efficacy and motivation explained this association. This study found that as MI time and number of provided sessions increased, participants' sexual risk behavior decreased. The effect of MI time and number of sessions on sexual behavior was mediated by self-efficacy but not by motivation to practice safer sex.

The Role of Self-Efficacy and Motivation to Explain the Effect of Motivational Interviewing Time on Changes in Risky Sexual Behavior among People Living with HIV: A Mediation Analysis

PubMed Central

Golin, Carol E.; Earp, Jo Anne; Maman, Suzanne; Suchindran, Chirayath; Zimmer, Catherine

2014-01-01

Little is known about the amount of Motivational Interviewing (MI) needed to reduce risky sexual behavior among People Living with HIV/AIDS (PLWHA) or the roles self-efficacy and motivation to practice safer sex play. Among 183 PLWHA who received safer sex MI and were surveyed every 4 months over a 12 month period, we used hierarchical negative binomial regression models to examine the association between amount of counseling time and sexual risk behavior. We performed mediation analysis to evaluate whether changes in self-efficacy and motivation explained this association. This study found that as MI time and number of provided sessions increased, participants’ sexual risk behavior decreased. The effect of MI time and number of sessions on sexual behavior was mediated by self-efficacy but not by motivation to practice safer sex. PMID:22228069

Risk factors for caries-free time: longitudinal study in early childhood.

PubMed

Cabral, Maria Beatriz Barreto de Sousa; Mota, Eduardo Luiz Andrade; Cangussu, Maria Cristina Teixeira; Vianna, Maria Isabel Pereira; Floriano, Fabiana Raynal

2017-12-04

To estimate time in days from the beginning of follow-up up to the development of dental caries in children under 30 months and to assess risk factors potentially affecting the development of the disease. The study population of the cohort study were children attending public, private, and charitable day care centers in Salvador, Northeastern Brazil, followed up for fourteen months. We used the multivariate Cox regression to estimate risk and Kaplan-Meier method to estimate the caries-free time. Of the 495 children studied, 112 developed caries (22.6%). Mean caries-free time was 248.6 (SD = 96.2) days. The comparasion of curves by age group (> 24 months) and children attending public day care showed more caries in a shorter period (p < 0.00). The following variables were important risk factors for increased rate of caries: district of origin (HR = 1.88, 95%CI 1.27-2.77), category of day care (HR = 3.88, 95%CI 2.04-7.38), age (HR = 1.77, 95%CI 1.15-2.74), bottle-feeding before sleep time after the age of 12 months (HR = 1.62, 95%CI 1.04-2.51), presence of active white spots (HR = 2.70, 95%CI 1.07-6.80), and living in non-masonry house (HR = 1.68, 95%CI 1.02-2.76). The highest hazard ratio (HR = 4.60, 95%CI 2.80-7.42) was found for previous caries experience. Social variables were considered as of high risk for the development of dental caries.

Local bladder cancer clusters in southeastern Michigan accounting for risk factors, covariates and residential mobility.

PubMed

Jacquez, Geoffrey M; Shi, Chen; Meliker, Jaymie R

2015-01-01

In case control studies disease risk not explained by the significant risk factors is the unexplained risk. Considering unexplained risk for specific populations, places and times can reveal the signature of unidentified risk factors and risk factors not fully accounted for in the case-control study. This potentially can lead to new hypotheses regarding disease causation. Global, local and focused Q-statistics are applied to data from a population-based case-control study of 11 southeast Michigan counties. Analyses were conducted using both year- and age-based measures of time. The analyses were adjusted for arsenic exposure, education, smoking, family history of bladder cancer, occupational exposure to bladder cancer carcinogens, age, gender, and race. Significant global clustering of cases was not found. Such a finding would indicate large-scale clustering of cases relative to controls through time. However, highly significant local clusters were found in Ingham County near Lansing, in Oakland County, and in the City of Jackson, Michigan. The Jackson City cluster was observed in working-ages and is thus consistent with occupational causes. The Ingham County cluster persists over time, suggesting a broad-based geographically defined exposure. Focused clusters were found for 20 industrial sites engaged in manufacturing activities associated with known or suspected bladder cancer carcinogens. Set-based tests that adjusted for multiple testing were not significant, although local clusters persisted through time and temporal trends in probability of local tests were observed. Q analyses provide a powerful tool for unpacking unexplained disease risk from case-control studies. This is particularly useful when the effect of risk factors varies spatially, through time, or through both space and time. For bladder cancer in Michigan, the next step is to investigate causal hypotheses that may explain the excess bladder cancer risk localized to areas of Oakland and Ingham

Explaining the black-white gap in cognitive test scores: Toward a theory of adverse impact.

PubMed

Cottrell, Jonathan M; Newman, Daniel A; Roisman, Glenn I

2015-11-01

In understanding the causes of adverse impact, a key parameter is the Black-White difference in cognitive test scores. To advance theory on why Black-White cognitive ability/knowledge test score gaps exist, and on how these gaps develop over time, the current article proposes an inductive explanatory model derived from past empirical findings. According to this theoretical model, Black-White group mean differences in cognitive test scores arise from the following racially disparate conditions: family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors (maternal sensitivity, maternal warmth and acceptance, and safe physical environment), child birth order, and child birth weight. Results from a 5-wave longitudinal growth model estimated on children in the NICHD Study of Early Child Care and Youth Development from ages 4 through 15 years show significant Black-White cognitive test score gaps throughout early development that did not grow significantly over time (i.e., significant intercept differences, but not slope differences). Importantly, the racially disparate conditions listed above can account for the relation between race and cognitive test scores. We propose a parsimonious 3-Step Model that explains how cognitive test score gaps arise, in which race relates to maternal disadvantage, which in turn relates to parenting factors, which in turn relate to cognitive test scores. This model and results offer to fill a need for theory on the etiology of the Black-White ethnic group gap in cognitive test scores, and attempt to address a missing link in the theory of adverse impact. (c) 2015 APA, all rights reserved).

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

NASA Astrophysics Data System (ADS)

Rodriguez-Fernandez, P.; White, A. E.; Howard, N. T.; Grierson, B. A.; Staebler, G. M.; Rice, J. E.; Yuan, X.; Cao, N. M.; Creely, A. J.; Greenwald, M. J.; Hubbard, A. E.; Hughes, J. W.; Irby, J. H.; Sciortino, F.

2018-02-01

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. This Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and time scales of cold-pulse experiments in tokamak plasmas.

A systematic review of methodology: time series regression analysis for environmental factors and infectious diseases.

PubMed

Imai, Chisato; Hashizume, Masahiro

2015-03-01

Time series analysis is suitable for investigations of relatively direct and short-term effects of exposures on outcomes. In environmental epidemiology studies, this method has been one of the standard approaches to assess impacts of environmental factors on acute non-infectious diseases (e.g. cardiovascular deaths), with conventionally generalized linear or additive models (GLM and GAM). However, the same analysis practices are often observed with infectious diseases despite of the substantial differences from non-infectious diseases that may result in analytical challenges. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, systematic review was conducted to elucidate important issues in assessing the associations between environmental factors and infectious diseases using time series analysis with GLM and GAM. Published studies on the associations between weather factors and malaria, cholera, dengue, and influenza were targeted. Our review raised issues regarding the estimation of susceptible population and exposure lag times, the adequacy of seasonal adjustments, the presence of strong autocorrelations, and the lack of a smaller observation time unit of outcomes (i.e. daily data). These concerns may be attributable to features specific to infectious diseases, such as transmission among individuals and complicated causal mechanisms. The consequence of not taking adequate measures to address these issues is distortion of the appropriate risk quantifications of exposures factors. Future studies should pay careful attention to details and examine alternative models or methods that improve studies using time series regression analysis for environmental determinants of infectious diseases.

Using a Multidimensional Measure of Resilience to Explain Life Satisfaction and Academic Achievement of Adults With Reading Difficulties.

PubMed

Stack-Cutler, Holly L; Parrila, Rauno K; Torppa, Minna

2015-01-01

We assessed the impact of intrapersonal and interpersonal resilience, persistence, and number of difficulties in addition to reading problems on life satisfaction (general, social, and self) and academic achievement. A total of 120 adults with reading difficulties who either were completing a university degree or were recent graduates responded to an in-lab or online survey. Results indicated that intrapersonal resilience correlated positively with interpersonal resilience and persistence, and both resilience factors were negatively associated with number of difficulties. Using structural equation modeling, intrapersonal resilience explained general satisfaction, intrapersonal resilience and number of difficulties explained self satisfaction, and interpersonal resilience explained social satisfaction. Academic achievement did not correlate with any of the included variables. © Hammill Institute on Disabilities 2014.

Explaining Ramps with Models

ERIC Educational Resources Information Center

Campbell, Todd; Neilson, Drew

2016-01-01

In this article Campbell and Neilson discuss several design strategies developed or adopted that were found particularly helpful when sequencing a unit that focused on learning about motion and acceleration. Students were expected to predict, observe, and explain why a ball traveled down one ramp faster than the other. Before engaging students,…

Explaining the Gender Gap in Help to Parents: The Importance of Employment

ERIC Educational Resources Information Center

Sarkisian, Natalia; Gerstel, Naomi

2004-01-01

Although it is well established that adult daughters spend more time giving assistance to their parents than do sons, the sources of this gender gap are not well understood. This paper asks: To what extent can this gap be explained by structural variation, especially the different rates of employment and kinds of jobs that women and men tend to…

Simple reaction time to the onset of time-varying sounds.

PubMed

Schlittenlacher, Josef; Ellermeier, Wolfgang

2015-10-01

Although auditory simple reaction time (RT) is usually defined as the time elapsing between the onset of a stimulus and a recorded reaction, a sound cannot be specified by a single point in time. Therefore, the present work investigates how the period of time immediately after onset affects RT. By varying the stimulus duration between 10 and 500 msec, this critical duration was determined to fall between 32 and 40 milliseconds for a 1-kHz pure tone at 70 dB SPL. In a second experiment, the role of the buildup was further investigated by varying the rise time and its shape. The increment in RT for extending the rise time by a factor of ten was about 7 to 8 msec. There was no statistically significant difference in RT between a Gaussian and linear rise shape. A third experiment varied the modulation frequency and point of onset of amplitude-modulated tones, producing onsets at different initial levels with differently rapid increase or decrease immediately afterwards. The results of all three experiments results were explained very well by a straightforward extension of the parallel grains model (Miller and Ulrich Cogn. Psychol. 46, 101-151, 2003), a probabilistic race model employing many parallel channels. The extension of the model to time-varying sounds made the activation of such a grain depend on intensity as a function of time rather than a constant level. A second approach by mechanisms known from loudness produced less accurate predictions.

Thermally-assisted Magma Emplacement Explains Restless Calderas.

PubMed

Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

2017-08-11

Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

The 'realities' of part-time nursing: a grounded theory study.

PubMed

Jamieson, Lynn N; Williams, Leonie Mosel; Lauder, William; Dwyer, Trudy

2008-10-01

To develop a theory that explains the 'realities' of part-time nursing. While little is known about the phenomenon of part-time nursing, increasing numbers of nurses work in part-time employment. Grounded theory. The problem that part-time nurses shared was an inability to achieve their personal optimal nursing potential. Motivators to work part-time, employment hours, specialty, individual and organizational factors formed contextual conditions that led to this problem. Part-time nurses responded to the challenges through a process of adaptation and adjustment. Harnessing the full productive potential of part-time nurses requires support to limit the difficulties that they encounter. The developed theory provides a valuable guide to managerial action. Nurse Managers need to consider the developed substantive theory when planning and managing nursing workforces.

Flynn Effects on Sub-Factors of Episodic and Semantic Memory: Parallel Gains over Time and the Same Set of Determining Factors

ERIC Educational Resources Information Center

Ronnlund, Michael; Nilsson, Lars-Goran.

2009-01-01

The study examined the extent to which time-related gains in cognitive performance, so-called Flynn effects, generalize across sub-factors of episodic memory (recall and recognition) and semantic memory (knowledge and fluency). We conducted time-sequential analyses of data drawn from the Betula prospective cohort study, involving four age-matched…

Factors affecting colonoscope insertion time in patients with or without a colostomy after left-sided colorectal resection.

PubMed

Jang, Hui Won; Kim, Yoon Nam; Nam, Chung Mo; Lee, Hyun Jung; Park, Soo Jung; Hong, Sung Pil; Kim, Tae Il; Kim, Won Ho; Cheon, Jae Hee

2012-12-01

We examined whether the insertion time for colonoscopies performed after left-sided resection was different in patients with a colostomy from that in patients without a colostomy and identified factors that could impact colonoscopy performance. We included consecutive patients who underwent colonoscopy between July 2005 and March 2011 after left-sided colorectal resection for colorectal cancer. We classified surgical methods according to the presence or absence of a colostomy and evaluated colonoscope insertion time retrospectively. Furthermore, we analyzed factors that might affect insertion time. A total of 1,041 patients underwent colonoscopy after left-sided colorectal resection during the study period. The colonoscopy completion rate was 98.6 %, and the mean insertion time was 6.1 ± 4.6 min (median 4.7 min, range 0.3-35.8 min). A shorter resection length of colon, the presence of a colostomy, and a lower endoscopist case volume were found to be independent factors associated with prolonged insertion time in patients with left-sided colorectal resection. Among experienced colonoscopists, no colonoscopy-associated or clinical factors were found to affect insertion time. However, a shorter resection length of colon, the presence of a colostomy, and poor bowel preparation were associated with prolonged insertion time among inexperienced endoscopists. We identified three factors that affect colonoscope insertion time after left-sided colorectal resection, including the presence of a colostomy. Inexperienced endoscopists were much more affected by the presence of a colostomy after left-sided colorectal resection. These findings have implications for the practice and teaching of colonoscopy after left-sided colorectal resection.

Factors that impact turnaround time of surgical pathology specimens in an academic institution.

PubMed

Patel, Samip; Smith, Jennifer B; Kurbatova, Ekaterina; Guarner, Jeannette

2012-09-01

Turnaround time of laboratory results is important for customer satisfaction. The College of American Pathologists' checklist requires an analytic turnaround time of 2 days or less for most routine cases and lets every hospital define what a routine specimen is. The objective of this study was to analyze which factors impact turnaround time of nonbiopsy surgical pathology specimens. We calculated the turnaround time from receipt to verification of results (adjusted for weekends and holidays) for all nonbiopsy surgical specimens during a 2-week period. Factors studied included tissue type, number of slides per case, decalcification, immunohistochemistry, consultations with other pathologists, and diagnosis. Univariate and multivariate analyses were performed. A total of 713 specimens were analyzed, 551 (77%) were verified within 2 days and 162 (23%) in 3 days or more. Lung, gastrointestinal, breast, and genitourinary specimens showed the highest percentage of cases being signed out in over 3 days. Diagnosis of malignancy (including staging of the neoplasia), consultation with other pathologists, having had a frozen section, and use of immunohistochemical stains were significantly associated with increased turnaround time in univariate analysis. Decalcification was not associated with increased turnaround time. In multivariate analysis, consultation with other pathologists, use of immunohistochemistry, diagnosis of malignancy, and the number of slides studied continued to be significantly associated with prolonged turnaround time. Our findings suggest that diagnosis of malignancy is central to significantly prolonging the turnaround time for surgical pathology specimens, thus institutions that serve cancer centers will have longer turnaround time than those that do not. Copyright © 2012 Elsevier Inc. All rights reserved.

A review of factors explaining variability in fentanyl pharmacokinetics; focus on implications for cancer patients

PubMed Central

Zandvliet, Maarten L.; Koolen, Stijn L. W.; Mathijssen, Ron H. J.; van der Rijt, Carin C. D.

2016-01-01

Fentanyl is a strong opioid that is available for various administration routes, and which is widely used to treat cancer‐related pain. Many factors influence the fentanyl pharmacokinetics leading to a wide inter‐ and intrapatient variability. This systematic review summarizes multiple studied factors that potentially influence fentanyl pharmacokinetics with a focus on implications for cancer patients. The use of CYP3A4 inhibitors and inducers, impaired liver function, and heating of the patch potentially influence fentanyl pharmacokinetics in a clinically relevant way. In elderly patients, current data suggest that we should carefully dose fentanyl due to alterations in absorption and metabolism. The influence of BMI and gender on fentanyl pharmacokinetics is questionable, most probably due to a large heterogeneity in the published studies. Pharmacogenetics, e.g. the CYP3A5*3 gene polymorphism, may influence fentanyl pharmacokinetics as well, although further study is warranted. Several other factors have been studied but did not show significant and clinically relevant effects on fentanyl pharmacokinetics. Unfortunately, most of the published papers that studied factors influencing fentanyl pharmacokinetics describe healthy volunteers instead of cancer patients. Results from the studies in volunteers may not be simply extrapolated to cancer patients because of multiple confounding factors. To handle fentanyl treatment in a population of cancer patients, it is essential that physicians recognize factors that influence fentanyl pharmacokinetics, thereby preventing potential side‐effects and increasing its efficacy. PMID:27619152

Genetic and environmental factors affecting birth size variation: a pooled individual-based analysis of secular trends and global geographical differences using 26 twin cohorts.

PubMed

Yokoyama, Yoshie; Jelenkovic, Aline; Hur, Yoon-Mi; Sund, Reijo; Fagnani, Corrado; Stazi, Maria A; Brescianini, Sonia; Ji, Fuling; Ning, Feng; Pang, Zengchang; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Rebato, Esther; Hopper, John L; Cutler, Tessa L; Saudino, Kimberly J; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Llewellyn, Clare H; Fisher, Abigail; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Bartels, Meike; van Beijsterveldt, Catharina E M; Willemsen, Gonneke; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas S; Craig, Jeffrey M; Saffery, Richard; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Haworth, Claire M A; Plomin, Robert; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Rasmussen, Finn; Tynelius, Per; Tarnoki, Adam D; Tarnoki, David L; Ooki, Syuichi; Rose, Richard J; Pietiläinen, Kirsi H; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko; Silventoinen, Karri

2018-05-19

The genetic architecture of birth size may differ geographically and over time. We examined differences in the genetic and environmental contributions to birthweight, length and ponderal index (PI) across geographical-cultural regions (Europe, North America and Australia, and East Asia) and across birth cohorts, and how gestational age modifies these effects. Data from 26 twin cohorts in 16 countries including 57 613 monozygotic and dizygotic twin pairs were pooled. Genetic and environmental variations of birth size were estimated using genetic structural equation modelling. The variance of birthweight and length was predominantly explained by shared environmental factors, whereas the variance of PI was explained both by shared and unique environmental factors. Genetic variance contributing to birth size was small. Adjusting for gestational age decreased the proportions of shared environmental variance and increased the propositions of unique environmental variance. Genetic variance was similar in the geographical-cultural regions, but shared environmental variance was smaller in East Asia than in Europe and North America and Australia. The total variance and shared environmental variance of birth length and PI were greater from the birth cohort 1990-99 onwards compared with the birth cohorts from 1970-79 to 1980-89. The contribution of genetic factors to birth size is smaller than that of shared environmental factors, which is partly explained by gestational age. Shared environmental variances of birth length and PI were greater in the latest birth cohorts and differed also across geographical-cultural regions. Shared environmental factors are important when explaining differences in the variation of birth size globally and over time.

Pattern identification in time-course gene expression data with the CoGAPS matrix factorization.

PubMed

Fertig, Elana J; Stein-O'Brien, Genevieve; Jaffe, Andrew; Colantuoni, Carlo

2014-01-01

Patterns in time-course gene expression data can represent the biological processes that are active over the measured time period. However, the orthogonality constraint in standard pattern-finding algorithms, including notably principal components analysis (PCA), confounds expression changes resulting from simultaneous, non-orthogonal biological processes. Previously, we have shown that Markov chain Monte Carlo nonnegative matrix factorization algorithms are particularly adept at distinguishing such concurrent patterns. One such matrix factorization is implemented in the software package CoGAPS. We describe the application of this software and several technical considerations for identification of age-related patterns in a public, prefrontal cortex gene expression dataset.

The Role of the Interplay between Stimulus Type and Timing in Explaining BCI-Illiteracy for Visual P300-Based Brain-Computer Interfaces

PubMed Central

Carabalona, Roberta

2017-01-01

Visual P300-based Brain-Computer Interface (BCI) spellers enable communication or interaction with the environment by flashing elements in a matrix and exploiting consequent changes in end-user's brain activity. Despite research efforts, performance variability and BCI-illiteracy still are critical issues for real world applications. Moreover, there is a quite unaddressed kind of BCI-illiteracy, which becomes apparent when the same end-user operates BCI-spellers intended for different applications: our aim is to understand why some well performers can become BCI-illiterate depending on speller type. We manipulated stimulus type (factor STIM: either characters or icons), color (factor COLOR: white, green) and timing (factor SPEED: fast, slow). Each BCI session consisted of training (without feedback) and performance phase (with feedback), both in copy-spelling. For fast flashing spellers, we observed a performance worsening for white icon-speller. Our findings are consistent with existing results reported on end-users using identical white×fast spellers, indicating independence of worsening trend from users' group. The use of slow stimulation timing shed a new light on the perceptual and cognitive phenomena related to the use of a BCI-speller during both the training and the performance phase. We found a significant STIM main effect for the N1 component on Pz and PO7 during the training phase and on PO8 during the performance phase, whereas in both phases neither the STIM×COLOR interaction nor the COLOR main effect was statistically significant. After collapsing data for factor COLOR, it emerged a statistically significant modulation of N1 amplitude depending to the phase of BCI session: N1 was more negative for icons than for characters both on Pz and PO7 (training), whereas the opposite modulation was observed for PO8 (performance). Results indicate that both feedback and expertise with respect to the stimulus type can modulate the N1 component and that icons

The Role of the Interplay between Stimulus Type and Timing in Explaining BCI-Illiteracy for Visual P300-Based Brain-Computer Interfaces.

PubMed

Carabalona, Roberta

2017-01-01

Visual P300-based Brain-Computer Interface (BCI) spellers enable communication or interaction with the environment by flashing elements in a matrix and exploiting consequent changes in end-user's brain activity. Despite research efforts, performance variability and BCI-illiteracy still are critical issues for real world applications. Moreover, there is a quite unaddressed kind of BCI-illiteracy, which becomes apparent when the same end-user operates BCI-spellers intended for different applications: our aim is to understand why some well performers can become BCI-illiterate depending on speller type. We manipulated stimulus type (factor STIM: either characters or icons), color (factor COLOR: white, green) and timing (factor SPEED: fast, slow). Each BCI session consisted of training (without feedback) and performance phase (with feedback), both in copy-spelling. For fast flashing spellers, we observed a performance worsening for white icon-speller. Our findings are consistent with existing results reported on end-users using identical white×fast spellers, indicating independence of worsening trend from users' group. The use of slow stimulation timing shed a new light on the perceptual and cognitive phenomena related to the use of a BCI-speller during both the training and the performance phase. We found a significant STIM main effect for the N1 component on P z and PO 7 during the training phase and on PO 8 during the performance phase, whereas in both phases neither the STIM×COLOR interaction nor the COLOR main effect was statistically significant. After collapsing data for factor COLOR, it emerged a statistically significant modulation of N1 amplitude depending to the phase of BCI session: N1 was more negative for icons than for characters both on P z and PO 7 (training), whereas the opposite modulation was observed for PO 8 (performance). Results indicate that both feedback and expertise with respect to the stimulus type can modulate the N1 component and that

[What factors help to explain satisfaction with Primary Health care in Spain?].

PubMed

Arrazola-Vacas, M; de Hevia-Payá, J; Rodríguez-Esteban, L

2015-01-01

To find out the factors that determine satisfaction with public primary health care in Spain. The work has considered a wide group of potential determining factors of that satisfaction, which are organised into 3 blocks of variables: Those related to the perceived quality in the care received, socioeconomic, and those relative to the state of health. The micro data of the Barómetro Sanitario (BS) of 2013, which are representative at a national level, were employed. After a prior first descriptive analysis, 2 multivariate models were estimated: One in which satisfaction is considered as being of a cardinal nature (regression model), and another in which it is contemplated as being of an ordinal nature (ordered probit model). There were practically no differences between the results obtained with one or other of the multivariate models. Not all the variables considered were statistically significant. Of the 3 blocks of variables studied, the one related to the perceived quality in the care received in the health centre exerts the greatest relevance in the explanation of satisfaction. The results obtained show that, by means of the management of the variables related to the perception of quality of care in health centres, public administrators and health professionals may have a highly favourable influence on the levels of satisfaction of primary health care patients. Copyright © 2015 SECA. Published by Elsevier Espana. All rights reserved.

A Systematic Review of Methodology: Time Series Regression Analysis for Environmental Factors and Infectious Diseases

PubMed Central

Imai, Chisato; Hashizume, Masahiro

2015-01-01

Background: Time series analysis is suitable for investigations of relatively direct and short-term effects of exposures on outcomes. In environmental epidemiology studies, this method has been one of the standard approaches to assess impacts of environmental factors on acute non-infectious diseases (e.g. cardiovascular deaths), with conventionally generalized linear or additive models (GLM and GAM). However, the same analysis practices are often observed with infectious diseases despite of the substantial differences from non-infectious diseases that may result in analytical challenges. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, systematic review was conducted to elucidate important issues in assessing the associations between environmental factors and infectious diseases using time series analysis with GLM and GAM. Published studies on the associations between weather factors and malaria, cholera, dengue, and influenza were targeted. Findings: Our review raised issues regarding the estimation of susceptible population and exposure lag times, the adequacy of seasonal adjustments, the presence of strong autocorrelations, and the lack of a smaller observation time unit of outcomes (i.e. daily data). These concerns may be attributable to features specific to infectious diseases, such as transmission among individuals and complicated causal mechanisms. Conclusion: The consequence of not taking adequate measures to address these issues is distortion of the appropriate risk quantifications of exposures factors. Future studies should pay careful attention to details and examine alternative models or methods that improve studies using time series regression analysis for environmental determinants of infectious diseases. PMID:25859149

Exploring the explaining quality of physics online explanatory videos

NASA Astrophysics Data System (ADS)

Kulgemeyer, Christoph; Peters, Cord H.

2016-11-01

Explaining skills are among the most important skills educators possess. Those skills have also been researched in recent years. During the same period, another medium has additionally emerged and become a popular source of information for learners: online explanatory videos, chiefly from the online video sharing website YouTube. Their content and explaining quality remain to this day mostly unmonitored, as well is their educational impact in formal contexts such as schools or universities. In this study, a framework for explaining quality, which has emerged from surveying explaining skills in expert-novice face-to-face dialogues, was used to explore the explaining quality of such videos (36 YouTube explanatory videos on Kepler’s laws and 15 videos on Newton’s third law). The framework consists of 45 categories derived from physics education research that deal with explanation techniques. YouTube provides its own ‘quality measures’ based on surface features including ‘likes’, views, and comments for each video. The question is whether or not these measures provide valid information for educators and students if they have to decide which video to use. We compared the explaining quality with those measures. Our results suggest that there is a correlation between explaining quality and only one of these measures: the number of content-related comments.

Risk factors for caries-free time: longitudinal study in early childhood

PubMed Central

Cabral, Maria Beatriz Barreto de Sousa; Mota, Eduardo Luiz Andrade; Cangussu, Maria Cristina Teixeira; Vianna, Maria Isabel Pereira; Floriano, Fabiana Raynal

2017-01-01

ABSTRACT OBJECTIVE To estimate time in days from the beginning of follow-up up to the development of dental caries in children under 30 months and to assess risk factors potentially affecting the development of the disease. METHODS The study population of the cohort study were children attending public, private, and charitable day care centers in Salvador, Northeastern Brazil, followed up for fourteen months. We used the multivariate Cox regression to estimate risk and Kaplan-Meier method to estimate the caries-free time. RESULTS Of the 495 children studied, 112 developed caries (22.6%). Mean caries-free time was 248.6 (SD = 96.2) days. The comparasion of curves by age group (> 24 months) and children attending public day care showed more caries in a shorter period (p < 0.00). The following variables were important risk factors for increased rate of caries: district of origin (HR = 1.88, 95%CI 1.27–2.77), category of day care (HR = 3.88, 95%CI 2.04–7.38), age (HR = 1.77, 95%CI 1.15–2.74), bottle-feeding before sleep time after the age of 12 months (HR = 1.62, 95%CI 1.04–2.51), presence of active white spots (HR = 2.70, 95%CI 1.07–6.80), and living in non-masonry house (HR = 1.68, 95%CI 1.02–2.76). The highest hazard ratio (HR = 4.60, 95%CI 2.80–7.42) was found for previous caries experience. CONCLUSIONS Social variables were considered as of high risk for the development of dental caries. PMID:29211203

Development of a dynamic framework to explain population patterns of leisure-time physical activity through agent-based modeling.

PubMed

Garcia, Leandro M T; Diez Roux, Ana V; Martins, André C R; Yang, Yong; Florindo, Alex A

2017-08-22

Despite the increasing body of evidences on the factors influencing leisure-time physical activity, our understanding of the mechanisms and interactions that lead to the formation and evolution of population patterns is still limited. Moreover, most frameworks in this field fail to capture dynamic processes. Our aim was to create a dynamic conceptual model depicting the interaction between key psychological attributes of individuals and main aspects of the built and social environments in which they live. This conceptual model will inform and support the development of an agent-based model aimed to explore how population patterns of LTPA in adults may emerge from the dynamic interplay between psychological traits and built and social environments. We integrated existing theories and models as well as available empirical data (both from literature reviews), and expert opinions (based on a systematic expert assessment of an intermediary version of the model). The model explicitly presents intention as the proximal determinant of leisure-time physical activity, a relationship dynamically moderated by the built environment (access, quality, and available activities) - with the strength of the moderation varying as a function of the person's intention- and influenced both by the social environment (proximal network's and community's behavior) and the person's behavior. Our conceptual model is well supported by evidence and experts' opinions and will inform the design of our agent-based model, as well as data collection and analysis of future investigations on population patterns of leisure-time physical activity among adults.

Factors Associated With Time to Site Activation, Randomization, and Enrollment Performance in a Stroke Prevention Trial.

PubMed

Demaerschalk, Bart M; Brown, Robert D; Roubin, Gary S; Howard, Virginia J; Cesko, Eldina; Barrett, Kevin M; Longbottom, Mary E; Voeks, Jenifer H; Chaturvedi, Seemant; Brott, Thomas G; Lal, Brajesh K; Meschia, James F; Howard, George

2017-09-01

Multicenter clinical trials attempt to select sites that can move rapidly to randomization and enroll sufficient numbers of patients. However, there are few assessments of the success of site selection. In the CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trials), we assess factors associated with the time between site selection and authorization to randomize, the time between authorization to randomize and the first randomization, and the average number of randomizations per site per month. Potential factors included characteristics of the site, specialty of the principal investigator, and site type. For 147 sites, the median time between site selection to authorization to randomize was 9.9 months (interquartile range, 7.7, 12.4), and factors associated with early site activation were not identified. The median time between authorization to randomize and a randomization was 4.6 months (interquartile range, 2.6, 10.5). Sites with authorization to randomize in only the carotid endarterectomy study were slower to randomize, and other factors examined were not significantly associated with time-to-randomization. The recruitment rate was 0.26 (95% confidence interval, 0.23-0.28) patients per site per month. By univariate analysis, factors associated with faster recruitment were authorization to randomize in both trials, principal investigator specialties of interventional radiology and cardiology, pre-trial reported performance >50 carotid angioplasty and stenting procedures per year, status in the top half of recruitment in the CREST trial, and classification as a private health facility. Participation in StrokeNet was associated with slower recruitment as compared with the non-StrokeNet sites. Overall, selection of sites with high enrollment rates will likely require customization to align the sites selected to the factor under study in the trial. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02089217. © 2017

Why Do Things Fall? How to Explain Why Gravity Is Not a Force

ERIC Educational Resources Information Center

Stannard, Warren B.

2018-01-01

In most high school physics classes, gravity is described as an attractive force between two masses as formulated by Newton over 300 years ago. Einstein's general theory of relativity implies that gravitational effects are instead the result of a "curvature" of space-time. However, explaining why things fall without resorting to Newton's…

Predicting Time to Hospital Discharge for Extremely Preterm Infants

PubMed Central

Hintz, Susan R.; Bann, Carla M.; Ambalavanan, Namasivayam; Cotten, C. Michael; Das, Abhik; Higgins, Rosemary D.

2010-01-01

As extremely preterm infant mortality rates have decreased, concerns regarding resource utilization have intensified. Accurate models to predict time to hospital discharge could aid in resource planning, family counseling, and perhaps stimulate quality improvement initiatives. Objectives For infants <27 weeks estimated gestational age (EGA), to develop, validate and compare several models to predict time to hospital discharge based on time-dependent covariates, and based on the presence of 5 key risk factors as predictors. Patients and Methods This was a retrospective analysis of infants <27 weeks EGA, born 7/2002-12/2005 and surviving to discharge from a NICHD Neonatal Research Network site. Time to discharge was modeled as continuous (postmenstrual age at discharge, PMAD), and categorical variables (“Early” and “Late” discharge). Three linear and logistic regression models with time-dependent covariate inclusion were developed (perinatal factors only, perinatal+early neonatal factors, perinatal+early+later factors). Models for Early and Late discharge using the cumulative presence of 5 key risk factors as predictors were also evaluated. Predictive capabilities were compared using coefficient of determination (R2) for linear models, and AUC of ROC curve for logistic models. Results Data from 2254 infants were included. Prediction of PMAD was poor, with only 38% of variation explained by linear models. However, models incorporating later clinical characteristics were more accurate in predicting “Early” or “Late” discharge (full models: AUC 0.76-0.83 vs. perinatal factor models: AUC 0.56-0.69). In simplified key risk factors models, predicted probabilities for Early and Late discharge compared favorably with observed rates. Furthermore, the AUC (0.75-0.77) were similar to those of models including the full factor set. Conclusions Prediction of Early or Late discharge is poor if only perinatal factors are considered, but improves substantially with

Genetic factors contribute to bleeding after cardiac surgery.

PubMed

Welsby, I J; Podgoreanu, M V; Phillips-Bute, B; Mathew, J P; Smith, P K; Newman, M F; Schwinn, D A; Stafford-Smith, M

2005-06-01

Postoperative bleeding remains a common, serious problem for cardiac surgery patients, with striking inter-patient variability poorly explained by clinical, procedural, and biological markers. We tested the hypothesis that genetic polymorphisms of coagulation proteins and platelet glycoproteins are associated with bleeding after cardiac surgery. Seven hundred and eighty patients undergoing aortocoronary surgery with cardiopulmonary bypass were studied. Clinical covariates previously associated with bleeding were recorded and DNA isolated from preoperative blood. Matrix Assisted Laser Desorption/Ionization, Time-Of-Flight (MALDI-TOF) mass spectroscopy or polymerase chain reaction were used for genotype analysis. Multivariable linear regression modeling, including all genetic main effects and two-way gene-gene interactions, related clinical and genetic predictors to bleeding from the thorax and mediastinum. Nineteen candidate polymorphisms were assessed; seven [GPIaIIa-52C>T and 807C>T, GPIb alpha 524C>T, tissue factor-603A>G, prothrombin 20210G>A, tissue factor pathway inhibitor-399C>T, and angiotensin converting enzyme (ACE) deletion/insertion] demonstrate significant association with bleeding (P < 0.01). Adding genetic to clinical predictors results improves the model, doubling overall ability to predict bleeding (P < 0.01). We identified seven genetic polymorphisms associated with bleeding after cardiac surgery. Genetic factors appear primarily independent of, and explain at least as much variation in bleeding as clinical covariates; combining genetic and clinical factors double our ability to predict bleeding after cardiac surgery. Accounting for genotype may be necessary when stratifying risk of bleeding after cardiac surgery.

Is the association between irritable bowel syndrome and abuse explained by neuroticism? A population based study

PubMed Central

Talley, N; Boyce, P; Jones, M

1998-01-01

Background—In outpatients and the community, an association between abuse (particularly sexual abuse) and irritable bowel syndrome (IBS) has been observed, but whether there is a causal link continues to be disputed. 
Aims—To test the hypothesis that psychological factors explain the apparent association between abuse and IBS. 
Methods—A sample of residents of Penrith (a Sydney suburb sociodemographically similar to the Australian population) selected randomly from the electoral rolls (that by law include the entire population of age 18 years and above) was mailed a validated self report questionnaire. Measured were gastrointestinal (GI) symptoms including the Rome criteria for IBS, abuse (including the standardised Drossman questions), neuroticism (Eysenck Personality Questionnaire), and psychological morbidity (General Health Questionnaire). 
Results—The response rate was 64% (n=730); 12% fulfilled the Rome criteria for IBS. Overall abuse in childhood (odds ratio (OR)=2.02, 95% confidence interval (CI) 1.29 to 3.15) but not adulthood (OR=1.39, 95% CI 0.88 to 2.19) was associazted with IBS univariately. Neuroticism and psychological morbidity were also univariately associated with abuse in childhood, abuse in adulthood, and IBS, respectively. However, by logistic regression, abuse in childhood was not associated with IBS after controlling for age, gender, and psychological factors (OR=1.34, 95% CI 0.83to 2.17). The results were not altered by restricting the analyses to more severe forms of abuse, and were not explained by interactions between abuse and psychological variables. 
Conclusion—There is an association between abuse and IBS in the community, but this may be explained in part by other psychological factors. Based on a path analysis, we postulate that abuse may induce the expression of neuroticism that in turn leads to IBS. 

 Keywords: epidemiology; irritable bowel syndrome; abuse; neuroticism PMID:9505885

Is the association between irritable bowel syndrome and abuse explained by neuroticism? A population based study.

PubMed

Talley, N J; Boyce, P M; Jones, M

1998-01-01

In outpatients and the community, an association between abuse (particularly sexual abuse) and irritable bowel syndrome (IBS) has been observed, but whether there is a causal link continues to be disputed. To test the hypothesis that psychological factors explain the apparent association between abuse and IBS. A sample of residents of Penrith (a Sydney suburb sociodemographically similar to the Australian population) selected randomly from the electoral rolls (that by law include the entire population of age 18 years and above) was mailed a validated self report questionnaire. Measured were gastrointestinal (GI) symptoms including the Rome criteria for IBS, abuse (including the standardised Drossman questions), neuroticism (Eysenck Personality Questionnaire), and psychological morbidity (General Health Questionnaire). The response rate was 64% (n = 730); 12% fulfilled the Rome criteria for IBS. Overall abuse in childhood (odds ratio (OR) = 2.02, 95% confidence interval (CI) 1.29 to 3.15) but not adulthood (OR = 1.39, 95% CI 0.88 to 2.19) was associated with IBS univariately. Neuroticism and psychological morbidity were also univariately associated with abuse in childhood, abuse in adulthood and IBS, respectively. However, by logistic regression, abuse in childhood was not associated with IBS after controlling for age, gender, and psychological factors (OR = 1.34, 95% CI 0.83 to 2.17). The results were not altered by restricting the analyses to more severe forms of abuse, and were not explained by interactions between abuse and psychological variables. There is an association between abuse and IBS in the community, but this may be explained in part by other psychological factors. Based on a path analysis, we postulate that abuse may induce the expression of neuroticism that in turn leads to IBS.

How regular blood donors explain their behavior.

PubMed

Belda Suárez, Isabel Maria; Fernández-Montoya, Antorio; Rodríguez Fernández, Andrés; López-Berrio, Antorio; Cillero-Peñuela, Manuel

2004-10-01

To understand repeated donation, it is crucial to know its meaning. This issue was explored by asking a sample of regular donors to explain why they maintain this behavior. Discourse analysis was conducted in five groups of regular donors, selected according to the setting and number of their donations (from 1990 to 2001), on their motivation, attitudes, commitment to donation, personality, and self-concept. Three discursive positions were distinguished in relation to the different cultural meanings attributed to blood donation. Blood donation was understood in a rational and evaluative manner by the majority but in an emotional, personalized, and stereotyped manner by a minority. Continual donation as a form of help was rationalized as a function of internal and external factors, notably personal convenience in comparison to other helping behaviors and ease of access to collection points. The discourse referents offered to the donor greatly influence the meanings they attribute to their behavior. Some promotional materials should be revised because they may not connect with the reasons for donating that people find most comprehensible.

Three explanations for biodiversity hotspots: small range size, geographical overlap and time for species accumulation. An Australian case study.

PubMed

Cook, Lyn G; Hardy, Nate B; Crisp, Michael D

2015-07-01

To understand the generation and maintenance of biodiversity hotspots, we tested three major hypotheses: rates of diversification, ecological limits to diversity, and time for species accumulation. Using dated molecular phylogenies, measures of species' range size and geographical clade overlap, niche modelling, and lineages-through-time plots of Australian Fabaceae, we compared the southwest Australia Floristic Region (SWAFR; a global biodiversity hotspot) with a latitudinally equivalent non-hotspot, southeast Australia (SEA). Ranges of species (real and simulated) were smaller in the SWAFR than in SEA. Geographical overlap of clades was significantly greater for Daviesia in the SWAFR than in SEA, but the inverse for Bossiaea. Lineage diversification rates over the past 10 Myr did not differ between the SWAFR and SEA in either genus. Interaction of multiple factors probably explains the differences in measured diversity between the two regions. Steeper climatic gradients in the SWAFR probably explain the smaller geographical ranges of both genera there. Greater geographical overlap of clades in the SWAFR, combined with a longer time in the region, can explain why Daviesia is far more species-rich there than in SEA. Our results indicate that the time for speciation and ecological limits hypotheses, in concert, can explain the differences in biodiversity. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Factors influencing pre-hospital care time intervals in Iran: a qualitative study.

PubMed

Khorasani-Zavareh, Davoud; Mohammadi, Reza; Bohm, Katarina

2018-06-23

Pre-hospital time management provides better access to victims of road traffic crashes (RTCs) and can help minimize preventable deaths, injuries and disabilities. While most studies have been focused on measuring various time intervals in the pre-hospital phase, to our best knowledge there is no study exploring the barriers and facilitators that affects these various intervals qualitatively. The present study aimed to explore factors affecting various time intervals relating to road traffic incidents in the pre-hospital phase and provides suggestions for improvements in Iran. The study was conducted during 2013-2014 at both the national and local level in Iran. Overall, 18 face-to-face interviews with emergency medical services (EMS) personnel were used for data collection. Qualitative content analysis was employed to analyze the data. The most important barriers in relation to pre-hospital intervals were related to the manner of cooperation by members of the public with the EMS and their involvement at the crash scene, as well as to pre-hospital system factors, including the number and location of EMS facilities, type and number of ambulances and manpower. These factors usually affect how rapidly the EMS can arrive at the scene of the crash and how quickly victims can be transferred to hospital. These two categories have six main themes: notification interval; activation interval; response interval; on-scene interval; transport interval; and delivery interval. Despite more focus on physical resources, cooperation from members of the public needs to be taken in account in order to achieve better pre-hospital management of the various intervals, possibly through the use of public education campaigns.

Does cultural integration explain a mental health advantage for adolescents?

PubMed Central

Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

2012-01-01

Background A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. Methods A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a ‘total difficulties score’ and by classification as a ‘probable clinical case’. Results A total of 6643 pupils in first and second years of secondary school (ages 11–13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005–06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Conclusions Cultural integration was associated with better mental health, independent of the mental health advantage

Does cultural integration explain a mental health advantage for adolescents?

PubMed

Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

2012-06-01

A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a 'total difficulties score' and by classification as a 'probable clinical case'. A total of 6643 pupils in first and second years of secondary school (ages 11-13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005-06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Cultural integration was associated with better mental health, independent of the mental health advantage found among specific ethnic groups: Black Caribbean and

Sleep Complaints in Older Blacks: Do Demographic and Health Indices Explain Poor Sleep Quality and Duration?

PubMed Central

Gamaldo, Alyssa A.; Gamaldo, Charlene E.; Allaire, Jason C.; Aiken-Morgan, Adrienne T.; Salas, Rachel E.; Szanton, Sarah; Whitfield, Keith E.

2014-01-01

Objective: To examine the relationship between measures of sleep quality and the presence of commonly encountered comorbid and sociodemographic conditions in elderly Black subjects. Method: Analyses included participants from the Baltimore Study of Black Aging (BSBA; n = 450; mean age 71.43 years; SD 9.21). Pittsburgh Sleep Quality Index (PSQI) measured overall sleep pattern and quality. Self-reported and objective measures of physical and mental health data and demographic information were collected for all participants. Results: Sociodemographic and comorbid health factors were significantly associated with sleep quality. Results from regression analyses revealed that older age, current financial strain, interpersonal problems, and stress were unique predictors of worse sleep quality. Sleep duration was significantly correlated with age, depressive affect, interpersonal problems, and stress; only age was a unique significant predictor. While participants 62 years or younger had worse sleep quality with increasing levels of stress, there was no significant relationship between sleep quality and stress for participants 81 years and older. Conclusions: Several potential mechanisms may explain poor sleep in urban, community dwelling Blacks. Perceived stressors, including current financial hardship or hardship experienced for an extended time period throughout the lifespan, may influence sleep later in life. Citation: Gamaldo AA, Gamaldo CE, Allaire JC, Aiken-Morgan AT, Salas RE, Szanton S, Whitfield KE. Sleep complaints in older blacks: do demographic and health indices explain poor sleep quality and duration? J Clin Sleep Med 2014;10(7):725-731. PMID:25024649

Factors Associated with Waiting Time for Access to Mental Health Services for Children and Adolescents in Norway

ERIC Educational Resources Information Center

Andersson, Helle Wessel

2004-01-01

The present study addresses the question of equality of access, as it relates to waiting time for specialised mental health treatment for children and adolescents. The aim was to investigate whether demographic, clinical factors and service-related factors were associated with waiting time. Data was based on a documentation system in which all…

Time-lag effects of global vegetation responses to climate change.

PubMed

Wu, Donghai; Zhao, Xiang; Liang, Shunlin; Zhou, Tao; Huang, Kaicheng; Tang, Bijian; Zhao, Wenqian

2015-09-01

Climate conditions significantly affect vegetation growth in terrestrial ecosystems. Due to the spatial heterogeneity of ecosystems, the vegetation responses to climate vary considerably with the diverse spatial patterns and the time-lag effects, which are the most important mechanism of climate-vegetation interactive effects. Extensive studies focused on large-scale vegetation-climate interactions use the simultaneous meteorological and vegetation indicators to develop models; however, the time-lag effects are less considered, which tends to increase uncertainty. In this study, we aim to quantitatively determine the time-lag effects of global vegetation responses to different climatic factors using the GIMMS3g NDVI time series and the CRU temperature, precipitation, and solar radiation datasets. First, this study analyzed the time-lag effects of global vegetation responses to different climatic factors. Then, a multiple linear regression model and partial correlation model were established to statistically analyze the roles of different climatic factors on vegetation responses, from which the primary climate-driving factors for different vegetation types were determined. The results showed that (i) both the time-lag effects of the vegetation responses and the major climate-driving factors that significantly affect vegetation growth varied significantly at the global scale, which was related to the diverse vegetation and climate characteristics; (ii) regarding the time-lag effects, the climatic factors explained 64% variation of the global vegetation growth, which was 11% relatively higher than the model ignoring the time-lag effects; (iii) for the area with a significant change trend (for the period 1982-2008) in the global GIMMS3g NDVI (P < 0.05), the primary driving factor was temperature; and (iv) at the regional scale, the variation in vegetation growth was also related to human activities and natural disturbances. Considering the time-lag effects is quite

A Dynamical System Approach Explaining the Process of Development by Introducing Different Time-scales.

PubMed

Hashemi Kamangar, Somayeh Sadat; Moradimanesh, Zahra; Mokhtari, Setareh; Bakouie, Fatemeh

2018-06-11

A developmental process can be described as changes through time within a complex dynamic system. The self-organized changes and emergent behaviour during development can be described and modeled as a dynamical system. We propose a dynamical system approach to answer the main question in human cognitive development i.e. the changes during development happens continuously or in discontinuous stages. Within this approach there is a concept; the size of time scales, which can be used to address the aforementioned question. We introduce a framework, by considering the concept of time-scale, in which "fast" and "slow" is defined by the size of time-scales. According to our suggested model, the overall pattern of development can be seen as one continuous function, with different time-scales in different time intervals.

Do family history of CHD, education, paternal social class, number of siblings and height explain the association between psychosocial factors at work and coronary heart disease? The Whitehall II study

PubMed Central

Hintsa, T; Shipley, M; Gimeno, D; Elovainio, M; Chandola, T; Jokela, M; Keltikangas-Järvinen, L; Vahtera, J; Marmot, MG; Kivimäki, M

2011-01-01

Objectives To examine whether the association between psychosocial factors at work and incident coronary heart disease (CHD) is explained by pre-employment factors such as family history of CHD, education, paternal social class, number of siblings and height. Methods A prospective cohort study of 6435 of British men aged 35–55 years at phase 1 (1985–1988) and free from prevalent CHD at phase 2 (1989–1990) was conducted. Psychosocial factors at work were assessed at phases 1 and 2 and mean scores across the two phases were used to determine long-term exposure. Selected pre-employment factors were assessed at phase 1. Follow-up for coronary death, first non-fatal myocardial infarction or definite angina between phase 2 and 1999 was based on clinical records (250 events, follow-up 8.7 years). Results Pre-employment factors were associated with risk for CHD: hazard ratio, HRs (95% CI) were 1.33 (1.03 to 1.73) for family history of CHD, 1.18 (1.05–1.32) for each quartile decrease in height, and marginally 1.16 (0.99–1.35) for each category increase in number of siblings. Psychosocial work factors predicted CHD: 1.72 (1.08–2.74) for low job control and 1.72 (1.10–2.67) for low organisational justice. Adjustment for pre-employment factors changed these associations by 4.1% or less. Conclusions In this well-characterised occupational cohort of British men, the association between psychosocial factors at work and CHD was largely independent of family history of CHD, education, paternal education and social class, number of siblings and height. PMID:19819857

Are relationships between pollen-ovule ratio and pollen and seed size explained by sex allocation?

PubMed

Burd, Martin

2011-10-01

Positive correlations between pollen-ovule ratio and seed size, and negative correlations between pollen-ovule ratio and pollen grain size have been noted frequently in a wide variety of angiosperm taxa. These relationships are commonly explained as a consequence of sex allocation on the basis of a simple model proposed by Charnov. Indeed, the theoretical expectation from the model has been the basis for interest in the empirical pattern. However, the predicted relationship is a necessary consequence of the mathematics of the model, which therefore has little explanatory power, even though its predictions are consistent with empirical results. The evolution of pollen-ovule ratios is likely to depend on selective factors affecting mating system, pollen presentation and dispensing, patterns of pollen receipt, pollen tube competition, female mate choice through embryo abortion, as well as genetic covariances among pollen, ovule, and seed size and other reproductive traits. To the extent the empirical correlations involving pollen-ovule ratios are interesting, they will need explanation in terms of a suite of selective factors. They are not explained simply by sex allocation trade-offs. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Health-related Quality of Life and Related Factors in Full-time and Part-time Workers.

PubMed

Kim, Byungsung; Kim, Wonjoon; Choi, Hyunrim; Won, Changwon; Kim, Youngshin

2012-07-01

There has been a rapid increase in the number of part-time workers in Korea with little information available on associated changes in quality of life. This study was designed to compare part-time and full-time workers in terms of the quality of life and related factors. Data were extracted from the 4th Korea National Health and Nutrition Examination Survey, conducted in 2008. Of the 1,284 participants selected, 942 were females (range, 20 to 64 years). Based on the information provided by self-administered questionnaire, subjects were categorized according to the working pattern (full-time and part-time) and working hours (<30 and ≥30 hours). Differences in socio-demographic characteristics, health-related behaviors, and job characteristics were assessed by t-test and chi-square test. EuroQol-five dimensions (EQ-5D) index was implemented in order to measure the quality of life. Differences in the EQ-5D index scores between the groups were compared by t-test, stepwise multivariate logistic regression analyses. Quality of life did not differ by work patterns. In males, the Organization for Economic Cooperation and Development part-time group was associated with poorer quality of life (odds ratio [OR], 0.49; P = 0.028). For both sexes, the non-stress group was linked with superior quality of life in comparison to the stress group (OR, 2.64; P = 0.002; OR, 2.17; P < 0.001). Female employees engaged in non-manual labor had superior quality of life than those engaged in manual labor (OR, 1.40; P = 0.027). This study concludes that working less than 30 hours per week is related to lower quality of life in comparison to working 30 hours or more in male employees in Korea.

Predicting College Success: The Relative Contributions of Five Social/Personality Factors, Five Cognitive/Learning Factors, and SAT Scores

PubMed Central

Hannon, Brenda

2014-01-01

To-date, studies have examined simultaneously the relative predictive powers of two or three factors on GPA. The present study examines the relative powers of five social/personality factors, five cognitive/learning factors, and SAT scores to predict freshmen and non-freshmen (sophomores, juniors, seniors) academic success (i.e., GPA). The results revealed many significant predictors of GPA for both freshmen and non-freshmen. However, subsequent regressions showed that only academic self-efficacy, epistemic belief of learning, and high-knowledge integration explained unique variance in GPA (19%-freshmen, 23.2%-non-freshmen). Further for freshmen, SAT scores explained an additional unique 10.6% variance after the influences attributed to these three predictors was removed whereas for non-freshmen, SAT scores failed to explain any additional variance. These results highlight the unique and important contributions of academic self-efficacy, epistemic belief of learning and high-knowledge integration to GPA beyond other previously-identified predictors. PMID:25568884

Explaining Changing Suicide Rates in Norway 1948-2004: The Role of Social Integration

ERIC Educational Resources Information Center

Barstad, Anders

2008-01-01

Using Norway 1948-2004 as a case, I test whether changes in variables related to social integration can explain changes in suicide rates. The method is the Box-Jenkins approach to time-series analysis. Different aspects of family integration contribute significantly to the explanation of Norwegian suicide rates in this period. The estimated effect…

Do early-life exposures explain why more advantaged children get eczema? Findings from the U.K. Millennium Cohort Study.

PubMed

Taylor-Robinson, D C; Williams, H; Pearce, A; Law, C; Hope, S

2016-03-01

Atopic dermatitis (eczema) in childhood is socially patterned, with higher incidence in more advantaged populations. However, it is unclear what factors explain the social differences. To identify early-life risk factors for eczema, and to explore how early-life risk factors explain any differences in eczema. We estimated odds ratios (ORs) for ever having had eczema by age 5 years in 14 499 children from the U.K. Millennium Cohort Study (MCS), with a focus on maternal, antenatal and early-life risk factors and socioeconomic circumstances (SECs). Risk factors were explored to assess whether they attenuated associations between SECs and eczema. Overall 35·1% of children had ever had eczema by age 5 years. Children of mothers with degree-level qualifications vs. no educational qualifications were more likely to have eczema (OR 1·52, 95% confidence interval 1·31-1·76), and there was a gradient across the socioeconomic spectrum. Maternal atopy, breastfeeding (1-6 weeks and ≥ 6 months), introduction of solids under 4 months or cow's milk under 9 months, antibiotic exposure in the first year of life and grime exposure were associated with an increased odds of having eczema. Female sex, Pakistani and Bangladeshi ethnicity, smoking during pregnancy, exposure to environmental tobacco smoke and having more siblings were associated with reduced odds for eczema. Controlling for maternal, antenatal and early-life characteristics (particularly maternal smoking during pregnancy, breastfeeding and number of siblings) reduced the OR for eczema to 1·26 (95% confidence interval 1·03-1·50) in the group with the highest educational qualifications compared with the least. In a representative U.K. child cohort, eczema was more common in more advantaged children. This was explained partially by early-life factors including not smoking during pregnancy, breastfeeding and having fewer siblings. © 2015 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

DOE PAGES

Rodriguez-Fernandez, P.; White, A. E.; Howard, N. T.; ...

2018-02-16

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. Here, this Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and timemore » scales of cold-pulse experiments in tokamak plasmas.« less

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez-Fernandez, P.; White, A. E.; Howard, N. T.

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. Here, this Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and timemore » scales of cold-pulse experiments in tokamak plasmas.« less

The Utility of the UTAUT Model in Explaining Mobile Learning Adoption in Higher Education in Guyana

ERIC Educational Resources Information Center

Thomas, Troy Devon; Singh, Lenandlar; Gaffar, Kemuel

2013-01-01

In this paper, we compare the utility of modified versions of the unified theory of acceptance and use of technology (UTAUT) model in explaining mobile learning adoption in higher education in a developing country and evaluate the size and direction of the impacts of the UTAUT factors on behavioural intention to adopt mobile learning in higher…

A Particle Model Explaining Mass and Relativity in a Physical Way

NASA Astrophysics Data System (ADS)

Giese, Albrecht

Physicists' understanding of relativity and the way it is handled is up to present days dominated by the interpretation of Albert Einstein, who related relativity to specific properties of space and time. The principal alternative to Einstein's interpretation is based on a concept proposed by Hendrik A. Lorentz, which uses knowledge of classical physics alone to explain relativistic phenomena. In this paper, we will show that on the one hand the Lorentz-based interpretation provides a simpler mathematical way of arriving at the known results for both Special and General Relativity. On the other hand, it is able to solve problems which have remained open to this day. Furthermore, a particle model will be presented, based on Lorentzian relativity and the quantum mechanical concept of Louis de Broglie, which explains the origin of mass without the use of the Higgs mechanism. It is based on the finiteness of the speed of light and provides classical results for particle properties which are currently only accessible through quantum mechanics.

Students' Understanding of Large Numbers as a Key Factor in Their Understanding of Geologic Time

ERIC Educational Resources Information Center

Cheek, Kim A.

2012-01-01

An understanding of geologic time is comprised of 2 facets. Events in Earth's history can be placed in relative and absolute temporal succession on a vast timescale. Rates of geologic processes vary widely, and some occur over time periods well outside human experience. Several factors likely contribute to an understanding of geologic time, one of…

Implicit leadership theories in applied settings: factor structure, generalizability, and stability over time.

PubMed

Epitropaki, Olga; Martin, Robin

2004-04-01

The present empirical investigation had a 3-fold purpose: (a) to cross-validate L. R. Offermann, J. K. Kennedy, and P. W. Wirtz's (1994) scale of Implicit Leadership Theories (ILTs) in several organizational settings and to further provide a shorter scale of ILTs in organizations; (b) to assess the generalizability of ILTs across different employee groups, and (c) to evaluate ILTs' change over time. Two independent samples were used for the scale validation (N1 = 500 and N2 = 439). A 6-factor structure (Sensitivity, Intelligence, Dedication, Dynamism, Tyranny, and Masculinity) was found to most accurately represent ELTs in organizational settings. Regarding the generalizability of ILTs, although the 6-factor structure was consistent across different employee groups, there was only partial support for total factorial invariance. Finally, evaluation of gamma, beta, and alpha change provided support for ILTs' stability over time.

An Electrochemical Framework to Explain Intergranular Stress Corrosion Cracking in an Al-5.4%Cu-0.5%Mg-0.5%Ag Alloy

NASA Technical Reports Server (NTRS)

Little, D. A.; Connolly, B. J.; Scully, J. R.

2001-01-01

A modified version of the Cu-depletion electrochemical framework was used to explain the metallurgical factor creating intergranular stress corrosion cracking susceptibility in an aged Al-Cu-Mg-Ag alloy, C416. This framework was also used to explain the increased resistance to intergranular stress corrosion cracking in the overaged temper. Susceptibility in the under aged and T8 condition is consistent with the grain boundary Cu-depletion mechanism. Improvements in resistance of the T8+ thermal exposure of 5000 h at 225 F (T8+) compared to the T8 condition can be explained by depletion of Cu from solid solution.

Proposed Pathophysiologic Framework to Explain Some ...

EPA Pesticide Factsheets

The paper proposes a pathophysiologic framework to explain the well-established epidemiological association between exposure to ambient air particle pollution and premature cardiovascular mortality, and offers insights into public health solutions that extend beyond regularory environmental protections to actions that can be taken by individuals, public health officials, healthcare professionals, city and regional planners, local and state governmental officials and all those who possess the capacity to improve cardiovascular health within the popula­tion.The foundation of the framework rests on the contribution of traditional cardiovascular risk factors acting alone and in concert with long-term exposures to air pollutants to create a conditional susceptibility for clinical vascular events, such as myocardial ischemia and infarction; stroke and lethal ventricular arrhythmias. The conceprual framework focuses on the fact that short-term exposures to ambient air particulate matter (PM) are associated with vascular thrombosis (acute coronary syndrome. stroke, deep venous thrombosis. and pulmonary embolism ) and electrical dysfunction (ventricular arrhythmia); and that individuals having prevalent heart disease are at greatest risk. Moreover, exposure is concomitant with changes in autonomic nervous system balance, systemic in­flammation, and prothrombotic/anti-thrombotic and profibrinolytic-antifibrinolytic balance.Thus, a comprehensive solution to the problem o

Influences of lifestyle factors on cardiac autonomic nervous system activity over time.

PubMed

Hu, Mandy Xian; Lamers, Femke; de Geus, Eco J C; Penninx, Brenda W J H

2017-01-01

Physical activity, alcohol use and smoking might affect cardiovascular disease through modifying autonomic nervous system (ANS) activity. We investigated: 1) whether there are consistent relationships between lifestyle factors and cardiac ANS activity over time, and 2) whether 2-year changes in lifestyle factors relate to 2-year changes in cardiac activity. Baseline (n=2618) and 2-year follow-up (n=2010) data of the Netherlands Study of Depression and Anxiety was combined. Baseline data was collected in the Netherlands from 2004-2007. Lifestyle factors were habitual physical activity, frequency of sport activities, alcohol use, and smoking. Indicators of cardiac activity were heart rate (HR), respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP) (100min of registration). The results showed that high physical activity (-1.8beats/min compared to low activity), high frequency of sport activities ('couple of times/week': -2.5beats/min compared to 'almost never') and mild/moderate alcohol use (-1.2beats/min compared to non-drinking) were related to low HR. Heavy smoking was related to high HR (>30cigarettes/day: +5.1beats/min compared to non-smoking). High frequency of sport activities was associated with high RSA ('couple of times/week':+1.7ms compared to 'almost never') and moderate smoking with longer PEP (11-20cigarettes/day: +2.8ms compared to non-smoking). Associations were consistent across waves. Furthermore, 2-year change in frequency of sport activities and number of smoked cigarettes/day was accompanied by 2-year change in HR (β=-0.076 and β=0.101, respectively) and RSA (β=0.046 and β=-0.040, respectively). Our findings support consistent effects of lifestyle on HR and parasympathetic activity in the expected direction. Cardiac autonomic dysregulation may be partly mediating the relationship between lifestyle and subsequent cardiovascular health. Copyright © 2016 Elsevier Inc. All rights reserved.

Multivariable analysis of anesthetic factors associated with time to extubation in dogs.

PubMed

Kleine, Stephanie; Hofmeister, Erik; Egan, Katrina

2014-12-01

The purpose of this study was to identify factors that prolong the time to extubation in dogs. Anesthetic records of 900 dogs at a university teaching hospital were searched. Multiple linear regression was used to compare independent predictors (patient demographics, anesthetic and intraoperative variables) with the dependent variable (time to extubation). Induction with propofol (P < 0.025) was associated with a shorter time to extubation, while premedication with acepromazine (P = 0.000) was associated with a longer time to extubation. Time to extubation was increased by 0.311 minutes for every kilogram increase in body weight (P = 0.000), 5.924 minutes for every 1 °C loss in body temperature (P = 0.0000), and by 0.096 minutes for every 1 minute increase in anesthetic duration (P = 0.000). Anesthetic variables, which can be manipulated by the anesthetist, include choice of premedication and induction drugs, hypothermia, and duration of anesthesia. Published by Elsevier Ltd.

[Survival time of HIV/AIDS cases and related factors in Beijing, 1995-2015].

PubMed

Li, Y; Wang, J; He, S F; Chen, J; Lu, H Y

2017-11-10

Objective: To analyze the survival time of HIV/AIDS cases and related factors in Beijing from 1995 to 2015. Methods: A retrospective cohort study was conducted to analyze the data of 12 874 HIV/AIDS cases. The data were collected from Chinese HIV/AIDS Comprehensive Information Management System. Life table method was applied to calculate the survival proportion, and Cox proportion hazard regression model were used to identify the factors related with survival time. Results: Among 12 874 HIV/AIDS cases, 303 (2.4%) died of AIDS related diseases; 9 346 (72.6%) received antiretroviral therapy. The average survival time was 226.5 months (95 %CI : 223.0-230.1), and the survival rates of 1, 5, 10, and 15 years were 98.2%, 96.4%, 93.2%, and 91.9% respectively. Multivariate Cox proportion hazard regression model showed that AIDS phase ( HR =1.439, 95 %CI : 1.041-1.989), heterosexual transmission ( HR =1.646, 95 %CI : 1.184-2.289), being married ( HR =2.186, 95 %CI : 1.510-3.164); older age (≥60 years) at diagnosis ( HR =6.608, 95 %CI : 3.546-12.316); lower CD(4)(+)T cell counts at diagnosis (<350 cells/μl) ( HR =8.711, 95 %CI : 5.757-13.181); receiving no antiretroviral therapy (ART) ( HR =18.223, 95 %CI : 13.317-24.937) were the high risk factors influencing the survival of AIDS patients compared with HIV phase, homosexual transmission, being unmarried, younger age (≤30 years), higher CD(4)(+)T cell count (≥350 cell/μl) and receiving ART. Conclusion: The average survival time of HIV/AIDS cases was 226.5 months after diagnoses. Receiving ART, higher CD(4)(+)T cell counts at the first test, HIV phase, younger age, being unmarried and the homosexual transmission were related to the longer survival time of HIV/AIDS cases. Receiving no ART, the lower CD(4)(+)T cell counts at the first test, AIDS phase, older age, being married and heterosexual transmission indicated higher risk of death due to AIDS.

Individual-Area Relationship Best Explains Goose Species Density in Wetlands

PubMed Central

Prins, Herbert H. T.; Cao, Lei; de Boer, Willem Fred

2015-01-01

Explaining and predicting animal distributions is one of the fundamental objectives in ecology and conservation biology. Animal habitat selection can be regulated by top-down and bottom-up processes, and is mediated by species interactions. Species varying in body size respond differently to top-down and bottom-up determinants, and hence understanding these allometric responses to those determinants is important for conservation. In this study, using two differently sized goose species wintering in the Yangtze floodplain, we tested the predictions derived from three different hypotheses (individual-area relationship, food resource and disturbance hypothesis) to explain the spatial and temporal variation in densities of two goose species. Using Generalized Linear Mixed Models with a Markov Chain Monte Carlo technique, we demonstrated that goose density was positive correlated with patch area size, suggesting that the individual area-relationship best predicts differences in goose densities. Moreover, the other predictions, related to food availability and disturbance, were not significant. Buffalo grazing probably facilitated greater white-fronted geese, as the number of buffalos was positively correlated to the density of this species. We concluded that patch area size is the most important factor determining the density of goose species in our study area. Patch area size is directly determined by water levels in the Yangtze floodplain, and hence modifying the hydrological regimes can enlarge the capacity of these wetlands for migratory birds. PMID:25996502

Astronomy Explained

NASA Astrophysics Data System (ADS)

North, Gerald

Every year large numbers of people take up the study of astronomy, mostly at amateur level. There are plenty of elementary books on the market, full of colourful photographs, but lacking in proper explanations of how and why things are as they are. Many people eventually wish to go beyond the 'coffee-table book' stage and study this fascinating subject in greater depth. This book is written for them. In addition, many people sit for public examinations in this subject each year and this book is also intended to be of use to them. All the topics from the GCSE syllabus are covered here, with sample questions at the end of each chapter. Astronomy Explained provides a comprehensive treatment of the subject in more depth than is usually found in elementary works, and will be of interest to both amateur astronomers and students of astronomy.

A critical review on physical factors and functional characteristics that may explain a sex/gender difference in work-related neck/shoulder disorders.

PubMed

Côté, Julie N

2012-01-01

The objective of this paper is to critically review recent literature on physical and functional sex/gender (s/g) differences, with focus on physical determinants associated with neck/shoulder musculoskeletal injuries. It is well known that there are s/g differences in anthropometrical and functional body characteristics (e.g. size and strength). However, s/g differences may be wrongly attributed if data analysis does not include appropriate corrections (e.g. by strength for endurance). Recent literature on motor control shows that there may indeed be s/g differences in muscle coordination and movement strategies during upper limb tasks that are not currently explained by methodological inadequacies. Moreover, recent studies have shown differences between men and women in sensory hypersensitivity characteristics associated with neck/shoulder injuries. Taken together, the literature points to the importance of accounting for possible s/g differences at all levels of the biopsychosocial system in order to better understand sex- and gender-specific issues relevant to workplace health. This article critically reviews recent literature and a conceptual model highlighting s/g differences in physical and functional characteristics related to neck/shoulder musculoskeletal disorders (NSMSD). Findings have implications on understanding how personal factors may affect NSMSD risk. With better understanding, practitioners can make more appropriate decisions to prevent work-related NSMSD.

Quantifying lead-time bias in risk factor studies of cancer through simulation.

PubMed

Jansen, Rick J; Alexander, Bruce H; Anderson, Kristin E; Church, Timothy R

2013-11-01

Lead-time is inherent in early detection and creates bias in observational studies of screening efficacy, but its potential to bias effect estimates in risk factor studies is not always recognized. We describe a form of this bias that conventional analyses cannot address and develop a model to quantify it. Surveillance Epidemiology and End Results (SEER) data form the basis for estimates of age-specific preclinical incidence, and log-normal distributions describe the preclinical duration distribution. Simulations assume a joint null hypothesis of no effect of either the risk factor or screening on the preclinical incidence of cancer, and then quantify the bias as the risk-factor odds ratio (OR) from this null study. This bias can be used as a factor to adjust observed OR in the actual study. For this particular study design, as average preclinical duration increased, the bias in the total-physical activity OR monotonically increased from 1% to 22% above the null, but the smoking OR monotonically decreased from 1% above the null to 5% below the null. The finding of nontrivial bias in fixed risk-factor effect estimates demonstrates the importance of quantitatively evaluating it in susceptible studies. Copyright © 2013 Elsevier Inc. All rights reserved.

The joint space-time statistics of macroweather precipitation, space-time statistical factorization and macroweather models.

PubMed

Lovejoy, S; de Lima, M I P

2015-07-01

Over the range of time scales from about 10 days to 30-100 years, in addition to the familiar weather and climate regimes, there is an intermediate "macroweather" regime characterized by negative temporal fluctuation exponents: implying that fluctuations tend to cancel each other out so that averages tend to converge. We show theoretically and numerically that macroweather precipitation can be modeled by a stochastic weather-climate model (the Climate Extended Fractionally Integrated Flux, model, CEFIF) first proposed for macroweather temperatures and we show numerically that a four parameter space-time CEFIF model can approximately reproduce eight or so empirical space-time exponents. In spite of this success, CEFIF is theoretically and numerically difficult to manage. We therefore propose a simplified stochastic model in which the temporal behavior is modeled as a fractional Gaussian noise but the spatial behaviour as a multifractal (climate) cascade: a spatial extension of the recently introduced ScaLIng Macroweather Model, SLIMM. Both the CEFIF and this spatial SLIMM model have a property often implicitly assumed by climatologists that climate statistics can be "homogenized" by normalizing them with the standard deviation of the anomalies. Physically, it means that the spatial macroweather variability corresponds to different climate zones that multiplicatively modulate the local, temporal statistics. This simplified macroweather model provides a framework for macroweather forecasting that exploits the system's long range memory and spatial correlations; for it, the forecasting problem has been solved. We test this factorization property and the model with the help of three centennial, global scale precipitation products that we analyze jointly in space and in time.

Key factors in children's competence to consent to clinical research.

PubMed

Hein, Irma M; Troost, Pieter W; Lindeboom, Robert; Benninga, Marc A; Zwaan, C Michel; van Goudoever, Johannes B; Lindauer, Ramón J L

2015-10-24

Although law is established on a strong presumption that persons younger than a certain age are not competent to consent, statutory age limits for asking children's consent to clinical research differ widely internationally. From a clinical perspective, competence is assumed to involve many factors including the developmental stage, the influence of parents and peers, and life experience. We examined potential determining factors for children's competence to consent to clinical research and to what extent they explain the variation in competence judgments. From January 1, 2012 through January 1, 2014, pediatric patients aged 6 to 18 years, eligible for clinical research studies were enrolled prospectively at various in- and outpatient pediatric departments. Children's competence to consent was assessed by MacArthur Competence Assessment Tool for Clinical Research. Potential determining child variables included age, gender, intelligence, disease experience, ethnicity and socio-economic status (SES). We used logistic regression analysis and change in explained variance in competence judgments to quantify the contribution of a child variable to the total explained variance. Contextual factors included risk and complexity of the decision to participate, parental competence judgment and the child's or parents decision to participate. Out of 209 eligible patients, 161 were included (mean age, 10.6 years, 47.2 % male). Age, SES, intelligence, ethnicity, complexity, parental competence judgment and trial participation were univariately associated with competence (P < 0.05). Total explained variance in competence judgments was 71.5 %. Only age and intelligence significantly and independently explained the variance in competence judgments, explaining 56.6 % and 12.7 % of the total variance respectively. SES, male gender, disease experience and ethnicity each explained less than 1 % of the variance in competence judgments. Contextual factors together explained an extra 2

Can we explain the observed methane variability after the Mount Pinatubo eruption?

NASA Astrophysics Data System (ADS)

Bândă, N.; Krol, M.; van Weele, M.; van Noije, T.; Le Sager, P.; Röckmann, T.

2016-01-01

The CH4 growth rate in the atmosphere showed large variations after the Pinatubo eruption in June 1991. A decrease of more than 10 ppb yr-1 in the growth rate over the course of 1992 was reported, and a partial recovery in the following year. Although several reasons have been proposed to explain the evolution of CH4 after the eruption, their contributions to the observed variations are not yet resolved. CH4 is removed from the atmosphere by the reaction with tropospheric OH, which in turn is produced by O3 photolysis under UV radiation. The CH4 removal after the Pinatubo eruption might have been affected by changes in tropospheric UV levels due to the presence of stratospheric SO2 and sulfate aerosols, and due to enhanced ozone depletion on Pinatubo aerosols. The perturbed climate after the eruption also altered both sources and sinks of atmospheric CH4. Furthermore, CH4 concentrations were influenced by other factors of natural variability in that period, such as El Niño-Southern Oscillation (ENSO) and biomass burning events. Emissions of CO, NOX and non-methane volatile organic compounds (NMVOCs) also affected CH4 concentrations indirectly by influencing tropospheric OH levels.

Potential drivers of CH4 variability are investigated using the TM5 global chemistry model. The contribution that each driver had to the global CH4 variability during the period 1990 to 1995 is quantified. We find that a decrease of 8-10 ppb yr-1 CH4 is explained by a combination of the above processes. However, the timing of the minimum growth rate is found 6&nash;9 months later than observed. The long-term decrease in CH4 growth rate over the period 1990 to 1995 is well captured and can be attributed to an increase in OH concentrations over this time period. Potential uncertainties in our modelled CH4 growth rate include emissions of CH4 from wetlands, biomass burning emissions of CH4 and other compounds, biogenic NMVOC and the sensitivity of OH to NMVOC emission changes

Can we explain the observed methane variability after the Mount Pinatubo eruption?

NASA Astrophysics Data System (ADS)

Bândă, N.; Krol, M.; van Weele, M.; van Noije, T.; Le Sager, P.; Röckmann, T.

2015-07-01

The CH4 growth rate in the atmosphere showed large variations after the Pinatubo eruption in June 1991. A decrease of more than 10 ppb yr-1 in the growth rate over the course of 1992 was reported and a partial recovery in the following year. Although several reasons have been proposed to explain the evolution of CH4 after the eruption, their contributions to the observed variations are not yet resolved. CH4 is removed from the atmosphere by the reaction with tropospheric OH, which in turn is produced by O3 photolysis under UV radiation. The CH4 removal after the Pinatubo eruption might have been affected by changes in tropospheric UV levels due to the presence of stratospheric SO2 and sulfate aerosols, and due to enhanced ozone depletion on Pinatubo aerosols. The perturbed climate after the eruption also altered both sources and sinks of atmospheric CH4. Furthermore, CH4 concentrations were influenced by other factors of natural variability in that period, such as ENSO and biomass burning events. Emissions of CO, NOX and NMVOCs also affected CH4 concentrations indirectly by influencing tropospheric OH levels. Potential drivers of CH4 variability are investigated using the TM5 global chemistry model. The contribution that each driver had to the global CH4 variability during the period 1990 to 1995 is quantified. We find that a decrease of 8-10 ppb yr-1 CH4 is explained by a combination of the above processes. However, the timing of the minimum growth rate is found 6-9 months later than observed. The long-term decrease in CH4 growth rate over the period 1990 to 1995 is well captured and can be attributed to an increase in OH concentrations over this time period. Potential uncertainties in our modelled CH4 growth rate include emissions of CH4 from wetlands, biomass burning emissions of CH4 and other compounds, biogenic NMVOC and the sensitivity of OH to NMVOC emission changes. Two inventories are used for CH4 emissions from wetlands, ORCHIDEE and LPJ, to investigate

A time-motion study of cardiovascular disease risk factor screening integrated into HIV clinic visits in Swaziland.

PubMed

Palma, Anton M; Rabkin, Miriam; Simelane, Samkelo; Gachuhi, Averie B; McNairy, Margaret L; Nuwagaba-Biribonwoha, Harriet; Bongomin, Pido; Okello, Velephi N; Bitchong, Raymond A; El-Sadr, Wafaa M

2018-03-01

Screening of modifiable cardiovascular disease (CVD) risk factors is recommended but not routinely provided for HIV-infected patients, especially in low-resource settings. Potential concerns include limited staff time and low patient acceptability, but little empirical data exists. As part of a pilot study of screening in a large urban HIV clinic in Swaziland, we conducted a time-motion study to assess the impact of screening on patient flow and HIV service delivery and exit interviews to assess patient acceptability. A convenience sample of patients ≥40 years of age attending routine HIV clinic visits was screened for hypertension, diabetes, hyperlipidemia and tobacco smoking. We observed HIV visits with and without screening and measured time spent on HIV and CVD risk factor screening activities. We compared screened and unscreened patients on total visit time and time spent receiving HIV services using Wilcoxon rank-sum tests. A separate convenience sample of screened patients participated in exit interviews to assess their satisfaction with screening. We observed 172 patient visits (122 with CVD risk factor screening and 50 without). Screening increased total visit time from a median (range) of 4 minutes (2 to 11) to 15 minutes (9 to 30) (p < 0.01). Time spent on HIV care was not affected: 4 (2 to 10) versus 4 (2 to 11) (p = 0.57). We recruited 126 patients for exit interviews, all of whom indicated that they would recommend screening to others. Provision of CVD risk factor screening more than tripled the length of routine HIV clinic visits but did not reduce the time spent on HIV services. Programme managers need to take longer visit duration into account in order to effectively integrate CVD risk factor screening and counselling into HIV programmes. © 2018 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of the International AIDS Society.

CaAP2 transcription factor is a candidate gene for a flowering repressor and a candidate for controlling natural variation of flowering time in Capsicum annuum.

PubMed

Borovsky, Yelena; Sharma, Vinod K; Verbakel, Henk; Paran, Ilan

2015-06-01

The APETALA2 transcription factor homolog CaAP2 is a candidate gene for a flowering repressor in pepper, as revealed by induced-mutation phenotype, and a candidate underlying a major QTL controlling natural variation in flowering time. To decipher the genetic control of transition to flowering in pepper (Capsicum spp.) and determine the extent of gene function conservation compared to model species, we isolated and characterized several ethyl methanesulfonate (EMS)-induced mutants that vary in their flowering time compared to the wild type. In the present study, we report on the isolation of an early-flowering mutant that flowers after four leaves on the primary stem compared to nine leaves in the wild-type 'Maor'. By genetic mapping and sequencing of putative candidate genes linked to the mutant phenotype, we identified a member of the APETALA2 (AP2) transcription factor family, CaAP2, which was disrupted in the early-flowering mutant. CaAP2 is a likely ortholog of AP2 that functions as a repressor of flowering in Arabidopsis. To test whether CaAP2 has an effect on controlling natural variation in the transition to flowering in pepper, we performed QTL mapping for flowering time in a cross between early and late-flowering C. annuum accessions. We identified a major QTL in a region of chromosome 2 in which CaAP2 was the most significant marker, explaining 52 % of the phenotypic variation of the trait. Sequence comparison of the CaAP2 open reading frames in the two parents used for QTL mapping did not reveal significant variation. In contrast, significant differences in expression level of CaAP2 were detected between near-isogenic lines that differ for the flowering time QTL, supporting the putative function of CaAP2 as a major repressor of flowering in pepper.

Explaining Infinite Series--An Exploration of Students' Images

ERIC Educational Resources Information Center

Champney, Danielle Dawn

2013-01-01

This study uses self-generated representations (SGR)--images produced in the act of explaining--as a means of uncovering what university calculus students understand about infinite series convergence. It makes use of student teaching episodes, in which students were asked to explain to a peer what that student might have missed had they been…

Explaining Racial Disparities in Child Asthma Readmission Using a Causal Inference Approach

PubMed Central

Beck, Andrew F.; Huang, Bin; Auger, Katherine A.; Ryan, Patrick H.; Chen, Chen; Kahn, Robert S.

2017-01-01

IMPORTANCE Childhood asthma is characterized by disparities in the experience of morbidity, including the risk for readmission to the hospital after an initial hospitalization. African American children have been shown to have more than 2 times the hazard of readmission when compared with their white counterparts. OBJECTIVE To explain why African American children are at greater risk for asthma-related readmissions than white children. DESIGN, SETTING, AND PARTICIPANTS This study was completed as part of the Greater Cincinnati Asthma Risks Study, a population-based, prospective, observational cohort. From August 2010 to October 2011, it enrolled 695 children, aged 1 to 16 years, admitted for asthma or wheezing who identified as African American (n = 441) or white (n = 254) in an inpatient setting of an urban, tertiary care children’s hospital. MAIN OUTCOMES AND MEASURES The main outcome was time to asthma-related readmission and race was the predictor. Biologic, environmental, disease management, access, and socioeconomic hardship variables were measured; their roles in understanding racial readmission disparities were conceptualized using a directed acyclic graphic. Inverse probability of treatment weighting balanced African American and white children with respect to key measured variables. Racial differences in readmission hazard were assessed using weighted Cox proportional hazards regression and Kaplan-Meier curves. RESULTS The sample was 65% male (n = 450), and the median age was 5.4 years. African American children were 2.26 times more likely to be readmitted than white children (95% CI, 1.56–3.26). African American children significantly differed with respect to nearly every measured biologic, environmental, disease management, access, and socioeconomic hardship variable. Socioeconomic hardship variables explained 53% of the observed disparity (hazard ratio, 1.47; 95% CI, 1.05–2.05). The addition of biologic, environmental, disease management, and

Teachers mathematical communication profile in explaining subject matter

NASA Astrophysics Data System (ADS)

Umami, Rohmatul; Budayasa, I. Ketut; Suwarsono, St.

2017-12-01

This study aimed to see a teachers mathematical communication profile in explaining a subject matter. It is a qualitative research. A high-school junior teacher (i.e., a teacher with 1- to 5-year experience) teaching mathematics at X-Social Class was selected as the subject of this study. The data was collected by observing the teachers mathematical communication in explaining a given material (i.e., the rule of sine) in class and an in-depth interview would be organized respectively. The result showed that the junior teacher explained the subject matter in systematic, complete, fluent, and centered manner. In this case, she began with reminding students on the previous material related to the current material to be learned, informing the current learning objectives, and finally delivering the subject matter. To support her explanation, the teacher also provided some related information, led the students attention into the given material by asking them particular related questions, and did not use any confusing terms. However, the study found that some of high-school teachers still used less appropriate language in explaining materials.

The Role of Patients and Providers in the Timing of Follow-up Visits

PubMed Central

Welch, H Gilbert; Chapko, Michael K; James, Kenneth E; Schwartz, Lisa M; Woloshin, Steven

1999-01-01

OBJECTIVE Although the decision about how frequently to see outpatients has a direct impact on a provider’s workload and may impact health care costs, revisit intervals have rarely been a topic of investigation. To begin to understand what factors are correlated with this decision, we examined baseline data from a Department of Veterans Affairs (VA) Cooperative Study designed to evaluate telephone care. DESIGN Observational study based on extensive patient data collected during enrollment into the randomized trial. Providers were required to recommend a revisit interval (e.g., “return visit in 3 months”) for each patient before randomization, under the assumption that the patient would be receiving clinic visits as usual. POPULATON/SETTING Five hundred seventy-one patients over age 55 cared for by one of the 30 providers working in three VA general medical clinics. Patients for whom immediate follow-up (≤2 weeks) was recommended were excluded. MEASUREMENTS Mean revisit interval was adjusted for patient factors using a regression model that accounted for patients being nested within providers and providers being nested within sites. Four patient-level variable blocks (illness burden–patient, travel time, illness burden–physician, and prior utilization) were sequentially entered into a linear model to determine their role in explaining the variance in revisit intervals. Physician identity was also entered after four blocks. MAIN RESULTS Recommended revisit intervals ranged from 1 month to over 1 year with the most common recommended intervals being 2, 3, or 6 months. About 10% of the variance in revisit interval was explained by illness measures independent of provider (e.g., general health perception) and travel time. Adding other illness measures (e.g., diagnoses, medications) and prior utilization (e.g., clinic visits) doubled the variance explained (R2= .21). Finally, the identification of individual provider doubled the explained variance again (R2

Inequity in access to dental care services explains current socioeconomic disparities in oral health: the Swedish National Surveys of Public Health 2004-2005.

PubMed

Wamala, Sarah; Merlo, Juan; Boström, Gunnel

2006-12-01

To analyse the effects of socioeconomic disadvantage on access to dental care services and on oral health. Design, setting and outcomes: Cross-sectional data from the Swedish National Surveys of Public Health 2004 and 2005. Outcomes were poor oral health (self-rated oral health and symptoms of periodontal disease) and lack of access to dental care services. A socioeconomic disadvantage index (SDI) was developed, consisting of social welfare beneficiary, being unemployed, financial crisis and lack of cash reserves. Swedish population-based sample of 17 362 men and 20 037 women. Every instance of increasing levels of socioeconomic disadvantage was associated with worsened oral health but, simultaneously, with decreased utilisation of dental care services. After adjusting for age, men with a mild SDI compared with those with no SDI had 2.7 (95% confidence interval (CI) 2.5 to 3.0) times the odds for self-rated poor oral health, whereas odds related to severe SDI were 6.8 (95% CI 6.2 to 7.5). The corresponding values among women were 2.3 (95% CI 2.1 to 2.5) and 6.8 (95% CI 6.3 to 7.5). Nevertheless, people with severe socioeconomic disparities were 7-9 times as likely to refrain from seeking the required dental treatment. These associations persisted even after controlling for living alone, education, occupational status and lifestyle factors. Lifestyle factors explained only 29% of the socioeconomic differences in poor oral health among men and women, whereas lack of access to dental care services explained about 60%. The results of the multilevel regression analysis indicated no additional effect of the administrative boundaries of counties or of municipalities in Sweden. Results call for urgent public health interventions to increase equitable access to dental care services.

Time to brain imaging in acute stroke is improving: secondary analysis of the INSTINCT trial.

PubMed

Sauser, Kori; Burke, James F; Levine, Deborah A; Scott, Phillip A; Meurer, William J

2014-01-01

Patients with acute ischemic stroke benefit from rapid evaluation and treatment, and timely brain imaging is a necessary component. We determined the effect of a targeted behavioral intervention on door-to-imaging time (DIT) among patients with ischemic stroke treated with tissue-type plasminogen activator. Second, we examined the variation in DIT accounted for by patient-level and hospital-level factors. The Increasing Stroke Treatment through Interventional behavioral Change Tactics (INSTINCT) trial was a cluster-randomized, controlled trial involving 24 Michigan hospitals. The intervention aimed to increase tissue-type plasminogen activator utilization. Detailed chart abstractions collected data for 557 patients with ischemic stroke. We used a series of hierarchical linear mixed-effects models to evaluate the effect of the intervention on DIT (difference-in-differences analysis) and used patient-level and hospital-level explanatory variables to decompose variation in DIT. DIT improved over time, without a difference between intervention and control hospitals (intervention: 23.7-19.3 minutes, control: 28.9-19.2 minutes; P=0.56). Adjusted DIT was faster in patients who arrived by ambulance (7.2 minutes; 95% confidence interval, 4.1-10.2), had severe strokes (1.0 minute per +5-point National Institutes of Health Stroke Scale; 95% confidence interval, 0.1-2.0), and presented in the postintervention period (4.9 minutes; 95% confidence interval, 2.3-7.4). After accounting for these factors, 13.8% of variation in DIT was attributable to hospital. Neither hospital stroke volume nor stroke center status was associated with DIT. Performance on DIT improved similarly in intervention and control hospitals, suggesting that nonintervention factors explain the improvement. Hospital-level factors explain a modest proportion of variation in DIT, but further research is needed to identify the hospital-level factors responsible.

Time to Brain Imaging in Acute Stroke is Improving: Secondary analysis of the INSTINCT Trial

PubMed Central

Sauser, Kori; Burke, James F.; Levine, Deborah A.; Scott, Phillip A.; Meurer, William J.

2014-01-01

Background and Purpose Acute ischemic stroke (IS) patients benefit from rapid evaluation and treatment, and timely brain imaging is a necessary component. We determined the effect of a targeted behavioral intervention on door-to-imaging-time (DIT) among IS patients treated with tissue plasminogen activator (tPA). Secondarily, we examined the variation in DIT accounted for by patient- and hospital-level factors. Methods The INSTINCT trial was a cluster-randomized, controlled trial involving 24 Michigan hospitals. The intervention aimed to increase tPA utilization. Detailed chart abstractions collected data for 557 IS patients. We used a series of hierarchical linear mixed-effects models to evaluate the effect of the intervention on DIT (difference-in-differences analysis) and used patient and hospital-level explanatory variables to decompose variation in DIT. Results DIT improved over time, without a difference between intervention and control hospitals (intervention: 23.7 to 19.3 minutes, control: 28.9 to 19.2 minutes, p=0.56). Adjusted DIT was faster in patients who arrived by ambulance (7.2 minutes; 95%CI 4.1–10.2), had severe strokes (1.0 minute per +5 point NIHSS; 95%CI 0.1–2.0), and presented in the post-intervention period (4.9 minutes; 95%CI 2.3–7.4). After accounting for these factors, 13.8% of variation in DIT was attributable to hospital. Neither hospital stroke volume nor stroke center status was associated with DIT. Conclusions Performance on DIT improved similarly in intervention and control hospitals suggesting that non-intervention factors explain the improvement. Hospital-level factors explain a modest proportion of variation in DIT but further research is needed to identify the hospital-level factors responsible. PMID:24232449

Regional variation in health care utilization in Sweden - the importance of demand-side factors.

PubMed

Johansson, Naimi; Jakobsson, Niklas; Svensson, Mikael

2018-06-04

Differences in health care utilization across geographical areas are well documented within several countries. If the variation across areas cannot be explained by differences in medical need, it can be a sign of inefficiency or misallocation of public health care resources. In this observational, longitudinal panel study we use regional level data covering the 21 Swedish regions (county councils) over 13 years and a random effects model to assess to what degree regional variation in outpatient physician visits is explained by observed demand factors such as health, demography and socio-economic factors. The results show that regional mortality, as a proxy for population health, and demography do not explain regional variation in visits to primary care physicians, but explain about 50% of regional variation in visits to outpatient specialists. Adjusting for socio-economic and basic supply-side factors explains 33% of the regional variation in primary physician visits, but adds nothing to explaining the variation in specialist visits. 50-67% of regional variation remains unexplained by a large number of observable regional characteristics, indicating that omitted and possibly unobserved factors contribute substantially to the regional variation. We conclude that variations in health care utilization across regions is not very well explained by underlying medical need and demand, measured by mortality, demographic and socio-economic factors.

Explaining errors in children's questions.

PubMed

Rowland, Caroline F

2007-07-01

The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that, as predicted by some generativist theories [e.g. Santelmann, L., Berk, S., Austin, J., Somashekar, S. & Lust. B. (2002). Continuity and development in the acquisition of inversion in yes/no questions: dissociating movement and inflection, Journal of Child Language, 29, 813-842], questions with auxiliary DO attracted higher error rates than those with modal auxiliaries. However, in wh-questions, questions with modals and DO attracted equally high error rates, and these findings could not be explained in terms of problems forming questions with why or negated auxiliaries. It was concluded that the data might be better explained in terms of a constructivist account that suggests that entrenched item-based constructions may be protected from error in children's speech, and that errors occur when children resort to other operations to produce questions [e.g. Dabrowska, E. (2000). From formula to schema: the acquisition of English questions. Cognitive Liguistics, 11, 83-102; Rowland, C. F. & Pine, J. M. (2000). Subject-auxiliary inversion errors and wh-question acquisition: What children do know? Journal of Child Language, 27, 157-181; Tomasello, M. (2003). Constructing a language: A usage-based theory of language acquisition. Cambridge, MA: Harvard University Press]. However, further work on constructivist theory development is required to allow researchers to make predictions about the nature of these operations.

Explaining the discrepancy between forced fold amplitude and sill thickness.

NASA Astrophysics Data System (ADS)

Hoggett, Murray; Jones, Stephen M.; Reston, Timothy; Magee, Craig; Jackson, Christopher AL

2017-04-01

Understanding the behaviour of Earth's surface in response to movement and emplacement of magma underground is important because it assists calculation of subsurface magma volumes, and could feed into eruption forecasting. Studies of seismic reflection data have observed that the amplitude of a forced fold above an igneous sill is usually smaller than the thickness of the sill itself. This observation implies that fold amplitude alone provides only a lower bound for magma volume, and an understanding of the mechanism(s) behind the fold amplitude/sill thickness discrepancy is also required to obtain a true estimate of magma volume. Mechanisms suggested to explain the discrepancy include problems with seismic imaging and varying strain behaviour of the host rock. Here we examine the extent to which host-rock compaction can explain the fold amplitude/sill thickness discrepancy. This mechanism operates in cases where a sill is injected into the upper few kilometres of sedimentary rock that contain significant porosity. Accumulation of sediment after sill intrusion reduces the amplitude of the forced fold by compaction, but the sill itself undergoes little compaction since its starting porosity is almost zero. We compiled a database of good-quality 2D and 3D seismic observations where sill thickness has been measured independently of forced fold geometry. We then backstripped the post-intrusion sedimentary section to reconstruct the amplitude of the forced fold at the time of intrusion. We used the standard compaction model in which porosity decays exponentially below the sediment surface. In all examples we studied, post-sill-emplacement compaction can explain all of the fold amplitude/sill thickness discrepancy, subject to uncertainty in compaction model parameters. This result leads directly to an improved method of predicting magma volume from fold amplitude, including how uncertainty in compaction parameters maps onto uncertainty in magma volume. Our work implies

Perceptions of First-Time in College Community College Students Regarding Factors and Barriers for Success

ERIC Educational Resources Information Center

Sheppard, Deana K.

2012-01-01

The purpose of this study was to examine the perceptions of first-generation first-time in college (FTIC) students who have completed a student success course (Learning Frameworks: First-Year Experience-EDUC 1300) at the community college level regarding (a) factors that enable them to succeed and (b) factors that are barriers to their success. A…

Time series with tailored nonlinearities

NASA Astrophysics Data System (ADS)

Räth, C.; Laut, I.

2015-10-01

It is demonstrated how to generate time series with tailored nonlinearities by inducing well-defined constraints on the Fourier phases. Correlations between the phase information of adjacent phases and (static and dynamic) measures of nonlinearities are established and their origin is explained. By applying a set of simple constraints on the phases of an originally linear and uncorrelated Gaussian time series, the observed scaling behavior of the intensity distribution of empirical time series can be reproduced. The power law character of the intensity distributions being typical for, e.g., turbulence and financial data can thus be explained in terms of phase correlations.

Does market competition explain fairness?

PubMed

Descioli, Peter

2013-02-01

The target article by Baumard et al. uses their previous model of bargaining with outside options to explain fairness and other features of human sociality. This theory implies that fairness judgments are determined by supply and demand but humans often perceive prices (divisions of surplus) in competitive markets to be unfair.

Coin Tossing Explains the Activity of Opposing Microtubule Motors on Phagosomes.

PubMed

Sanghavi, Paulomi; D'Souza, Ashwin; Rai, Ashim; Rai, Arpan; Padinhatheeri, Ranjith; Mallik, Roop

2018-05-07

How the opposing activity of kinesin and dynein motors generates polarized distribution of organelles inside cells is poorly understood and hotly debated [1, 2]. Possible explanations include stochastic mechanical competition [3, 4], coordinated regulation by motor-associated proteins [5-7], mechanical activation of motors [8], and lipid-induced organization [9]. Here, we address this question by using phagocytosed latex beads to generate early phagosomes (EPs) that move bidirectionally along microtubules (MTs) in an in vitro assay [9]. Dynein/kinesin activity on individual EPs is recorded as real-time force generation of the motors against an optical trap. Activity of one class of motors frequently coincides with, or is rapidly followed by opposite motors. This leads to frequent and rapid reversals of EPs in the trap. Remarkably, the choice between dynein and kinesin can be explained by the tossing of a coin. Opposing motors therefore appear to function stochastically and independently of each other, as also confirmed by observing no effect on kinesin function when dynein is inhibited on the EPs. A simple binomial probability calculation based on the geometry of EP-microtubule contact explains the observed activity of dynein and kinesin on phagosomes. This understanding of intracellular transport in terms of a hypothetical coin, if it holds true for other cargoes, provides a conceptual framework to explain the polarized localization of organelles inside cells. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

The compression of perceived time in a hot environment depends on physiological and psychological factors.

PubMed

Tamm, Maria; Jakobson, Ainika; Havik, Merle; Burk, Andres; Timpmann, Saima; Allik, Jüri; Oöpik, Vahur; Kreegipuu, Kairi

2014-01-01

The human perception of time was observed under extremely hot conditions. Young healthy men performed a time production task repeatedly in 4 experimental trials in either a temperate (22 °C, relative humidity 35%) or a hot (42 °C, relative humidity 18%) environment and with or without a moderate-intensity treadmill exercise. Within 1 hour, the produced durations indicated a significant compression of short intervals (0.5 to 10 s) in the combination of exercising and high ambient temperature, while neither variable/condition alone was enough to yield the effect. Temporal judgement was analysed in relation to different indicators of arousal, such as critical flicker frequency (CFF), core temperature, heart rate, and subjective ratings of fatigue and exertion. The arousal-sensitive internal clock model (originally proposed by Treisman) is used to explain the temporal compression while exercising in heat. As a result, we suggest that the psychological response to heat stress, the more precisely perceived fatigue, is important in describing the relationship between core temperature and time perception. Temporal compression is related to higher core temperature, but only if a certain level of perceived fatigue is accounted for, implying the existence of a thermoemotional internal clock.

EuroQol 5D Quality of Life in Meniere's Disorder Can Be Explained with Symptoms and Disabilities

ERIC Educational Resources Information Center

Levo, Hilla; Stephens, Dafydd; Poe, Dennis; Kentala, Erna; Rasku, Jyrki; Pyykko, Ilmari

2012-01-01

The purpose of this study was to determine the factors explaining changes in the generic quality of life among patients with Meniere's disorder (MD) and to evaluate the EuroQol 5D (EQ-5D) quality-of-life measures. A questionnaire focusing on symptoms and disabilities caused by MD was collected from 726 individuals. General health-related quality…

Gender and General Strain Theory: A Comparison of Strains, Mediating, and Moderating Effects Explaining Three Types of Delinquency

ERIC Educational Resources Information Center

Moon, Byongook; Morash, Merry

2017-01-01

The present study of 659 Korean adolescents tests General Strain Theory's (GST) utility in explaining gender differences in delinquency causation. It models the effects of key strains, negative emotions, and a composite measure of several conditioning factors separately for boys and girls and for delinquency. Consistent with the theory, males and…

Physical load during work and leisure time as risk factors for back pain.

PubMed

Hoogendoorn, W E; van Poppel, M N; Bongers, P M; Koes, B W; Bouter, L M

1999-10-01

This systematic review assessed aspects of physical load during work and leisure time as risk factors for back pain. Several reviews on this topic are available, but this one is based on a strict systematic approach to identify and summarize the evidence, comparable with that applied in the clinical literature on the efficacy of intervention for back pain. A computerized bibliographical search was made of several data bases for studies with a cohort or case-referent design. Cross-sectional studies were excluded. A rating system was used to assess the strength of the evidence, based on the methodological quality of 28 cohort and 3 case-referent studies and the consistency of the findings. Strong evidence exists for manual materials handling, bending and twisting, and whole-body vibration as risk factors for back pain. The evidence was moderate for patient handling and heavy physical work, and no evidence was found for standing or walking, sitting, sports, and total leisure-time physical activity.

Evolutionary genetic models of the ovarian time bomb hypothesis for the evolution of genomic imprinting.

PubMed Central

Weisstein, Anton E; Feldman, Marcus W; Spencer, Hamish G

2002-01-01

At a small number of loci in eutherian mammals, only one of the two copies of a gene is expressed; the other is silenced. Such loci are said to be "imprinted," with some having the maternally inherited allele inactivated and others showing paternal inactivation. Several hypotheses have been proposed to explain how such a genetic system could evolve in the face of the selective advantages of diploidy. In this study, we examine the "ovarian time bomb" hypothesis, which proposes that imprinting arose through selection for reduced risk of ovarian trophoblastic disease in females. We present three evolutionary genetic models that incorporate both this selection pressure and the effect of deleterious mutations to elucidate the conditions under which imprinting could evolve. Our findings suggest that the ovarian time bomb hypothesis can explain why some growth-enhancing genes active in early embryogenesis [e.g., mouse insulin-like growth factor 2 (Igf2)] have evolved to be maternally rather than paternally inactive and why the opposite imprinting status has evolved at some growth-inhibiting loci [e.g., mouse insulin-like growth factor 2 receptor (Igf2r)]. PMID:12242251

Species traits and climate velocity explain geographic range shifts in an ocean-warming hotspot.

PubMed

Sunday, Jennifer M; Pecl, Gretta T; Frusher, Stewart; Hobday, Alistair J; Hill, Nicole; Holbrook, Neil J; Edgar, Graham J; Stuart-Smith, Rick; Barrett, Neville; Wernberg, Thomas; Watson, Reg A; Smale, Dan A; Fulton, Elizabeth A; Slawinski, Dirk; Feng, Ming; Radford, Ben T; Thompson, Peter A; Bates, Amanda E

2015-09-01

Species' ranges are shifting globally in response to climate warming, with substantial variability among taxa, even within regions. Relationships between range dynamics and intrinsic species traits may be particularly apparent in the ocean, where temperature more directly shapes species' distributions. Here, we test for a role of species traits and climate velocity in driving range extensions in the ocean-warming hotspot of southeast Australia. Climate velocity explained some variation in range shifts, however, including species traits more than doubled the variation explained. Swimming ability, omnivory and latitudinal range size all had positive relationships with range extension rate, supporting hypotheses that increased dispersal capacity and ecological generalism promote extensions. We find independent support for the hypothesis that species with narrow latitudinal ranges are limited by factors other than climate. Our findings suggest that small-ranging species are in double jeopardy, with limited ability to escape warming and greater intrinsic vulnerability to stochastic disturbances. © 2015 John Wiley & Sons Ltd/CNRS.

The joint space-time statistics of macroweather precipitation, space-time statistical factorization and macroweather models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lovejoy, S., E-mail: lovejoy@physics.mcgill.ca; Lima, M. I. P. de; Department of Civil Engineering, University of Coimbra, 3030-788 Coimbra

2015-07-15

Over the range of time scales from about 10 days to 30–100 years, in addition to the familiar weather and climate regimes, there is an intermediate “macroweather” regime characterized by negative temporal fluctuation exponents: implying that fluctuations tend to cancel each other out so that averages tend to converge. We show theoretically and numerically that macroweather precipitation can be modeled by a stochastic weather-climate model (the Climate Extended Fractionally Integrated Flux, model, CEFIF) first proposed for macroweather temperatures and we show numerically that a four parameter space-time CEFIF model can approximately reproduce eight or so empirical space-time exponents. In spitemore » of this success, CEFIF is theoretically and numerically difficult to manage. We therefore propose a simplified stochastic model in which the temporal behavior is modeled as a fractional Gaussian noise but the spatial behaviour as a multifractal (climate) cascade: a spatial extension of the recently introduced ScaLIng Macroweather Model, SLIMM. Both the CEFIF and this spatial SLIMM model have a property often implicitly assumed by climatologists that climate statistics can be “homogenized” by normalizing them with the standard deviation of the anomalies. Physically, it means that the spatial macroweather variability corresponds to different climate zones that multiplicatively modulate the local, temporal statistics. This simplified macroweather model provides a framework for macroweather forecasting that exploits the system's long range memory and spatial correlations; for it, the forecasting problem has been solved. We test this factorization property and the model with the help of three centennial, global scale precipitation products that we analyze jointly in space and in time.« less

A model for diagnosing and explaining multiple disorders.

PubMed

Jamieson, P W

1991-08-01

The ability to diagnose multiple interacting disorders and explain them in a coherent causal framework has only partially been achieved in medical expert systems. This paper proposes a causal model for diagnosing and explaining multiple disorders whose key elements are: physician-directed hypotheses generation, object-oriented knowledge representation, and novel explanation heuristics. The heuristics modify and link the explanations to make the physician aware of diagnostic complexities. A computer program incorporating the model currently is in use for diagnosing peripheral nerve and muscle disorders. The program successfully diagnoses and explains interactions between diseases in terms of underlying pathophysiologic concepts. The model offers a new architecture for medical domains where reasoning from first principles is difficult but explanation of disease interactions is crucial for the system's operation.

Explaining Errors in Children's Questions

ERIC Educational Resources Information Center

Rowland, Caroline F.

2007-01-01

The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that,…

Birdsong dialect patterns explained using magnetic domains

NASA Astrophysics Data System (ADS)

Burridge, James; Kenney, Steven

2016-06-01

The songs and calls of many bird species, like human speech, form distinct regional dialects. We suggest that the process of dialect formation is analogous to the physical process of magnetic domain formation. We take the coastal breeding grounds of the Puget Sound white crowned sparrow as an example. Previous field studies suggest that birds of this species learn multiple songs early in life, and when establishing a territory for the first time, retain one of these dialects in order to match the majority of their neighbors. We introduce a simple lattice model of the process, showing that this matching behavior can produce single dialect domains provided the death rate of adult birds is sufficiently low. We relate death rate to thermodynamic temperature in magnetic materials, and calculate the critical death rate by analogy with the Ising model. Using parameters consistent with the known behavior of these birds we show that coastal dialect domain shapes may be explained by viewing them as low-temperature "stripe states."

Risk factors and epidemiological characteristics of new neonatal porcine diarrhoea syndrome in four Danish herds

PubMed Central

2014-01-01

Background The epidemiology of New Neonatal Porcine Diarrhoea Syndrome (NNPDS) was studied in four selected herds. A total of 941 new born piglets in 86 litters were evaluated for five consecutive days. NNPDS is a newly emerged syndrome, characterized by diarrhoea within the first week of life, which is un-responsive to antibiotics and not associated with known pathogens. The aetiology behind the syndrome is unknown, and specific risk factors predisposing piglets to develop NNPDS also remain to be determined. The study evaluated sow and piglet-level risk factors for developing NNPDS and described the epidemiologic characteristics within four herds previously diagnosed with the syndrome. NNPDS was defined as diarrhoea at any time-point during the second to fifth day of life. Results NNPDS was observed in a total of 60% (range: 39%-89%) of first parity piglets and 36% (range: 19-65%) of piglets born by mature sows. In total of 26% of piglets had liquid faeces on the day of birth. Approximately half of these piglets developed NNPDS. In the majority of cases (50-70% of cases within herds) symptoms started on the second or third day of life. Piglets in Herd 1 had12.8 times higher probability of developing NNPDS than piglets in Herd 4. First parity piglets had a 4.1 higher probability of developing NNPDS than piglets born by mature sows. Birth weight and faecal consistency on the day of birth were minor risk factors, each significant within one herd. Conclusions The most important factors associated with NNPDS were herd of origin and sow-parity. The reason for one of the herds experiencing a considerably more severe outbreak than the others was not explained by factors addressed in this study. The epidemiological pattern of diarrhoea varied a lot between herds; however, in all herds first parity piglets seemed predisposed. This association may be explained by an infectious background of the syndrome, but further studies are needed to explain this association. PMID

The Dimensionality of Reasoning: Inductive and Deductive Inference can be Explained by a Single Process.

PubMed

Hayes, Brett K; Stephens, Rachel G; Ngo, Jeremy; Dunn, John C

2018-02-01

Three-experiments examined the number of qualitatively different processing dimensions needed to account for inductive and deductive reasoning. In each study, participants were presented with arguments that varied in logical validity and consistency with background knowledge (believability), and evaluated them according to deductive criteria (whether the conclusion was necessarily true given the premises) or inductive criteria (whether the conclusion was plausible given the premises). We examined factors including working memory load (Experiments 1 and 2), individual working memory capacity (Experiments 1 and 2), and decision time (Experiment 3), which according to dual-processing theories, modulate the contribution of heuristic and analytic processes to reasoning. A number of empirical dissociations were found. Argument validity affected deduction more than induction. Argument believability affected induction more than deduction. Lower working memory capacity reduced sensitivity to argument validity and increased sensitivity to argument believability, especially under induction instructions. Reduced decision time led to decreased sensitivity to argument validity. State-trace analyses of each experiment, however, found that only a single underlying dimension was required to explain patterns of inductive and deductive judgments. These results show that the dissociations, which have traditionally been seen as supporting dual-processing models of reasoning, are consistent with a single-process model that assumes a common evidentiary scale for induction and deduction. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Evaluation of Effective Factors on Travel Time in Optimization of Bus Stops Placement Using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Bargegol, Iraj; Ghorbanzadeh, Mahyar; Ghasedi, Meisam; Rastbod, Mohammad

2017-10-01

In congested cities, locating and proper designing of bus stops according to the unequal distribution of passengers is crucial issue economically and functionally, since this subject plays an important role in the use of bus system by passengers. Location of bus stops is a complicated subject; by reducing distances between stops, walking time decreases, but the total travel time may increase. In this paper, a specified corridor in the city of Rasht in north of Iran is studied. Firstly, a new formula is presented to calculate the travel time, by which the number of stops and consequently, the travel time can be optimized. An intended corridor with specified number of stops and distances between them is addressed, the related formulas to travel time are created, and its travel time is calculated. Then the corridor is modelled using a meta-heuristic method in order that the placement and the optimal distances of bus stops for that are determined. It was found that alighting and boarding time along with bus capacity are the most effective factors affecting travel time. Consequently, it is better to have more concentration on indicated factors for improving the efficiency of bus system.

A Two-Factor Model Better Explains Heterogeneity in Negative Symptoms: Evidence from the Positive and Negative Syndrome Scale.

PubMed

Jang, Seon-Kyeong; Choi, Hye-Im; Park, Soohyun; Jaekal, Eunju; Lee, Ga-Young; Cho, Young Il; Choi, Kee-Hong

2016-01-01

Acknowledging separable factors underlying negative symptoms may lead to better understanding and treatment of negative symptoms in individuals with schizophrenia. The current study aimed to test whether the negative symptoms factor (NSF) of the Positive and Negative Syndrome Scale (PANSS) would be better represented by expressive and experiential deficit factors, rather than by a single factor model, using confirmatory factor analysis (CFA). Two hundred and twenty individuals with schizophrenia spectrum disorders completed the PANSS; subsamples additionally completed the Brief Negative Symptom Scale (BNSS) and the Motivation and Pleasure Scale-Self-Report (MAP-SR). CFA results indicated that the two-factor model fit the data better than the one-factor model; however, latent variables were closely correlated. The two-factor model's fit was significantly improved by accounting for correlated residuals between N2 (emotional withdrawal) and N6 (lack of spontaneity and flow of conversation), and between N4 (passive social withdrawal) and G16 (active social avoidance), possibly reflecting common method variance. The two NSF factors exhibited differential patterns of correlation with subdomains of the BNSS and MAP-SR. These results suggest that the PANSS NSF would be better represented by a two-factor model than by a single-factor one, and support the two-factor model's adequate criterion-related validity. Common method variance among several items may be a potential source of measurement error under a two-factor model of the PANSS NSF.