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Sample records for multilevel survival analysis

  1. Multilevel survival analysis of health inequalities in life expectancy

    Directory of Open Access Journals (Sweden)

    Merlo Juan

    2009-08-01

    Full Text Available Abstract Background The health status of individuals is determined by multiple factors operating at both micro and macro levels and the interactive effects of them. Measures of health inequalities should reflect such determinants explicitly through sources of levels and combining mean differences at group levels and the variation of individuals, for the benefits of decision making and intervention planning. Measures derived recently from marginal models such as beta-binomial and frailty survival, address this issue to some extent, but are limited in handling data with complex structures. Beta-binomial models were also limited in relation to measuring inequalities of life expectancy (LE directly. Methods We propose a multilevel survival model analysis that estimates life expectancy based on survival time with censored data. The model explicitly disentangles total health inequalities in terms of variance components of life expectancy compared to the source of variation at the level of individuals in households and parishes and so on, and estimates group differences of inequalities at the same time. Adjusted distributions of life expectancy by gender and by household socioeconomic level are calculated. Relative and absolute health inequality indices are derived based on model estimates. The model based analysis is illustrated on a large Swedish cohort of 22,680 men and 26,474 women aged 65–69 in 1970 and followed up for 30 years. Model based inequality measures are compared to the conventional calculations. Results Much variation of life expectancy is observed at individual and household levels. Contextual effects at Parish and Municipality level are negligible. Women have longer life expectancy than men and lower inequality. There is marked inequality by the level of household socioeconomic status measured by the median life expectancy in each socio-economic group and the variation in life expectancy within each group. Conclusion Multilevel

  2. Examining the Influence of Campus Climate on Students' Time to Degree: A Multilevel Discrete-Time Survival Analysis

    Science.gov (United States)

    Zhou, Ji; Castellanos, Michelle

    2013-01-01

    Utilizing longitudinal data of 3477 students from 28 institutions, we examine the effects of structural diversity and quality of interracial relation on students' persistence towards graduation within six years. We utilize multilevel discrete-time survival analysis to account for the longitudinal persistence patterns as well as the nested…

  3. Bruxism and dental implant failures: a multilevel mixed effects parametric survival analysis approach.

    Science.gov (United States)

    Chrcanovic, B R; Kisch, J; Albrektsson, T; Wennerberg, A

    2016-11-01

    Recent studies have suggested that the insertion of dental implants in patients being diagnosed with bruxism negatively affected the implant failure rates. The aim of the present study was to investigate the association between the bruxism and the risk of dental implant failure. This retrospective study is based on 2670 patients who received 10 096 implants at one specialist clinic. Implant- and patient-related data were collected. Descriptive statistics were used to describe the patients and implants. Multilevel mixed effects parametric survival analysis was used to test the association between bruxism and risk of implant failure adjusting for several potential confounders. Criteria from a recent international consensus (Lobbezoo et al., J Oral Rehabil, 40, 2013, 2) and from the International Classification of Sleep Disorders (International classification of sleep disorders, revised: diagnostic and coding manual, American Academy of Sleep Medicine, Chicago, 2014) were used to define and diagnose the condition. The number of implants with information available for all variables totalled 3549, placed in 994 patients, with 179 implants reported as failures. The implant failure rates were 13·0% (24/185) for bruxers and 4·6% (155/3364) for non-bruxers (P < 0·001). The statistical model showed that bruxism was a statistically significantly risk factor to implant failure (HR 3·396; 95% CI 1·314, 8·777; P = 0·012), as well as implant length, implant diameter, implant surface, bone quantity D in relation to quantity A, bone quality 4 in relation to quality 1 (Lekholm and Zarb classification), smoking and the intake of proton pump inhibitors. It is suggested that the bruxism may be associated with an increased risk of dental implant failure.

  4. The median hazard ratio: a useful measure of variance and general contextual effects in multilevel survival analysis.

    Science.gov (United States)

    Austin, Peter C; Wagner, Philippe; Merlo, Juan

    2017-03-15

    Multilevel data occurs frequently in many research areas like health services research and epidemiology. A suitable way to analyze such data is through the use of multilevel regression models (MLRM). MLRM incorporate cluster-specific random effects which allow one to partition the total individual variance into between-cluster variation and between-individual variation. Statistically, MLRM account for the dependency of the data within clusters and provide correct estimates of uncertainty around regression coefficients. Substantively, the magnitude of the effect of clustering provides a measure of the General Contextual Effect (GCE). When outcomes are binary, the GCE can also be quantified by measures of heterogeneity like the Median Odds Ratio (MOR) calculated from a multilevel logistic regression model. Time-to-event outcomes within a multilevel structure occur commonly in epidemiological and medical research. However, the Median Hazard Ratio (MHR) that corresponds to the MOR in multilevel (i.e., 'frailty') Cox proportional hazards regression is rarely used. Analogously to the MOR, the MHR is the median relative change in the hazard of the occurrence of the outcome when comparing identical subjects from two randomly selected different clusters that are ordered by risk. We illustrate the application and interpretation of the MHR in a case study analyzing the hazard of mortality in patients hospitalized for acute myocardial infarction at hospitals in Ontario, Canada. We provide R code for computing the MHR. The MHR is a useful and intuitive measure for expressing cluster heterogeneity in the outcome and, thereby, estimating general contextual effects in multilevel survival analysis. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

  5. Analysis of multilevel grouped survival data with time-varying regression coefficients.

    Science.gov (United States)

    Wong, May C M; Lam, K F; Lo, Edward C M

    2011-02-10

    Correlated or multilevel grouped survival data are common in medical and dental research. Two common approaches to analyze such data are the marginal and the random-effects approaches. Models and methods in the literature generally assume that the treatment effect is constant over time. A researcher may be interested in studying whether the treatment effects in a clinical trial vary over time, say fade out gradually. This is of particular clinical value when studying the long-term effect of a treatment. This paper proposed to extend the random effects grouped proportional hazards models by incorporating the possibly time-varying covariate effects into the model in terms of a state-space formulation. The proposed model is very flexible and the estimation can be performed using the MCMC approach with non-informative priors in the Bayesian framework. The method is applied to a data set from a prospective clinical trial investigating the effectiveness of silver diamine fluoride (SDF) and sodium fluoride (NaF) varnish in arresting active dentin caries in the Chinese preschool children. It is shown that the treatment groups with caries removal prior to the topical fluoride applications are most effective in shortening the arrest times in the first 6-month interval, but their effects fade out rapidly since then. The effects of treatment groups without caries removal prior to topical fluoride application drop at a very slow rate and can be considered as more or less constant over time. The applications of SDF solution is found to be more effective than the applications of NaF vanish.

  6. Multilevel component analysis

    NARCIS (Netherlands)

    Timmerman, M.E.

    2006-01-01

    A general framework for the exploratory component analysis of multilevel data (MLCA) is proposed. In this framework, a separate component model is specified for each group of objects at a certain level. The similarities between the groups of objects at a given level can be expressed by imposing cons

  7. Handbook of Advanced Multilevel Analysis

    CERN Document Server

    Hox, Joop

    2010-01-01

    This new handbook is the definitive resource on advanced topics related to multilevel analysis. The editors have assembled the top minds in the field to address the latest applications of multilevel modeling as well as the specific difficulties and methodological problems that are becoming more common as more complicated models are developed.

  8. Multilevel mixed effects parametric survival models using adaptive Gauss-Hermite quadrature with application to recurrent events and individual participant data meta-analysis.

    Science.gov (United States)

    Crowther, Michael J; Look, Maxime P; Riley, Richard D

    2014-09-28

    Multilevel mixed effects survival models are used in the analysis of clustered survival data, such as repeated events, multicenter clinical trials, and individual participant data (IPD) meta-analyses, to investigate heterogeneity in baseline risk and covariate effects. In this paper, we extend parametric frailty models including the exponential, Weibull and Gompertz proportional hazards (PH) models and the log logistic, log normal, and generalized gamma accelerated failure time models to allow any number of normally distributed random effects. Furthermore, we extend the flexible parametric survival model of Royston and Parmar, modeled on the log-cumulative hazard scale using restricted cubic splines, to include random effects while also allowing for non-PH (time-dependent effects). Maximum likelihood is used to estimate the models utilizing adaptive or nonadaptive Gauss-Hermite quadrature. The methods are evaluated through simulation studies representing clinically plausible scenarios of a multicenter trial and IPD meta-analysis, showing good performance of the estimation method. The flexible parametric mixed effects model is illustrated using a dataset of patients with kidney disease and repeated times to infection and an IPD meta-analysis of prognostic factor studies in patients with breast cancer. User-friendly Stata software is provided to implement the methods. Copyright © 2014 John Wiley & Sons, Ltd.

  9. Does Prison Crowding Predict Higher Rates of Substance Use Related Parole Violations? A Recurrent Events Multi-Level Survival Analysis.

    Science.gov (United States)

    Ruderman, Michael A; Wilson, Deirdra F; Reid, Savanna

    2015-01-01

    This administrative data-linkage cohort study examines the association between prison crowding and the rate of post-release parole violations in a random sample of prisoners released with parole conditions in California, for an observation period of two years (January 2003 through December 2004). Crowding overextends prison resources needed to adequately protect inmates and provide drug rehabilitation services. Violence and lack of access to treatment are known risk factors for drug use and substance use disorders. These and other psychosocial effects of crowding may lead to higher rates of recidivism in California parolees. Rates of parole violation for parolees exposed to high and medium levels of prison crowding were compared to parolees with low prison crowding exposure. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using a Cox model for recurrent events. Our dataset included 13070 parolees in California, combining individual level parolee data with aggregate level crowding data for multilevel analysis. Comparing parolees exposed to high crowding with those exposed to low crowding, the effect sizes from greatest to least were absconding violations (HR 3.56 95% CI: 3.05-4.17), drug violations (HR 2.44 95% CI: 2.00-2.98), non-violent violations (HR 2.14 95% CI: 1.73-2.64), violent and serious violations (HR 1.88 95% CI: 1.45-2.43), and technical violations (HR 1.86 95% CI: 1.37-2.53). Prison crowding predicted higher rates of parole violations after release from prison. The effect was magnitude-dependent and particularly strong for drug charges. Further research into whether adverse prison experiences, such as crowding, are associated with recidivism and drug use in particular may be warranted.

  10. Handbook of multilevel analysis

    National Research Council Canada - National Science Library

    Leeuw, Jan de; Meijer, Erik

    2008-01-01

    ... appropriate and efficient model-based methods have become available to deal with this issue, that we have come to appreciate the power that more complex models provide for describing the world and providing new insights. This book sets out to present some of the most recent developments in what has come to be known as multilevel modelling. An...

  11. Multilevel analysis in CSCL research

    NARCIS (Netherlands)

    Janssen, J.J.H.M.; Erkens, G.; Kirschner, P.A.; Kanselaar, G.

    2011-01-01

    The aim of this chapter is to explain why multilevel analysis (MLA) is often necessary to correctly answer the questions CSCL researchers address. Although CSCL researchers continue to use statistical techniques such as analysis of vari-ance or regression analysis, their datasets are often not suite

  12. Associations of all-cause mortality with census-based neighbourhood deprivation and population density in Japan: a multilevel survival analysis.

    Directory of Open Access Journals (Sweden)

    Tomoki Nakaya

    Full Text Available BACKGROUND: Despite evidence that neighbourhood conditions affect residents' health, no prospective studies of the association between neighbourhood socio-demographic factors and all-cause mortality have been conducted in non-Western societies. Thus, we examined the effects of areal deprivation and population density on all-cause mortality in Japan. METHODS: We employed census and survival data from the Japan Public Health Center-based Prospective Study, Cohort I (n = 37,455, consisting of middle-aged residents (40 to 59 years at the baseline in 1990 living in four public health centre districts. Data spanned between 1990 and 2010. A multilevel parametric proportional-hazard regression model was applied to estimate the hazard ratios (HRs of all-cause mortality by two census-based areal variables--areal deprivation index and population density--as well as individualistic variables such as socioeconomic status and various risk factors. RESULTS: We found that areal deprivation and population density had moderate associations with all-cause mortality at the neighbourhood level based on the survival data with 21 years of follow-ups. Even when controlling for individualistic socio-economic status and behavioural factors, the HRs of the two areal factors (using quartile categorical variables significantly predicted mortality. Further, this analysis indicated an interaction effect of the two factors: areal deprivation prominently affects the health of residents in neighbourhoods with high population density. CONCLUSIONS: We confirmed that neighbourhood socio-demographic factors are significant predictors of all-cause death in Japanese non-metropolitan settings. Although further study is needed to clarify the cause-effect relationship of this association, the present findings suggest that health promotion policies should consider health disparities between neighbourhoods and possibly direct interventions towards reducing mortality in densely

  13. Survival Analysis

    CERN Document Server

    Miller, Rupert G

    2011-01-01

    A concise summary of the statistical methods used in the analysis of survival data with censoring. Emphasizes recently developed nonparametric techniques. Outlines methods in detail and illustrates them with actual data. Discusses the theory behind each method. Includes numerous worked problems and numerical exercises.

  14. Factorial invariance in multilevel confirmatory factor analysis.

    Science.gov (United States)

    Ryu, Ehri

    2014-02-01

    This paper presents a procedure to test factorial invariance in multilevel confirmatory factor analysis. When the group membership is at level 2, multilevel factorial invariance can be tested by a simple extension of the standard procedure. However level-1 group membership raises problems which cannot be appropriately handled by the standard procedure, because the dependency between members of different level-1 groups is not appropriately taken into account. The procedure presented in this article provides a solution to this problem. This paper also shows Muthén's maximum likelihood (MUML) estimation for testing multilevel factorial invariance across level-1 groups as a viable alternative to maximum likelihood estimation. Testing multilevel factorial invariance across level-2 groups and testing multilevel factorial invariance across level-1 groups are illustrated using empirical examples. SAS macro and Mplus syntax are provided.

  15. Single-Level and Multilevel Mediation Analysis

    Science.gov (United States)

    Tofighi, Davood; Thoemmes, Felix

    2014-01-01

    Mediation analysis is a statistical approach used to examine how the effect of an independent variable on an outcome is transmitted through an intervening variable (mediator). In this article, we provide a gentle introduction to single-level and multilevel mediation analyses. Using single-level data, we demonstrate an application of structural…

  16. Multilevel exploratory factor analysis of discrete data

    NARCIS (Netherlands)

    Barendse, M.T.; Oort, F.J.; Jak, S.; Timmerman, M.E.

    2013-01-01

    Exploratory factor analysis (EFA) can be used to determine the dimensionality of a set of items. When data come from clustered subjects, such as pupils within schools or children within families, the hierarchical structure of the data should be taken into account. Standard multilevel EFA is only sui

  17. An Original Stepwise Multilevel Logistic Regression Analysis of Discriminatory Accuracy

    DEFF Research Database (Denmark)

    Merlo, Juan; Wagner, Philippe; Ghith, Nermin

    2016-01-01

    BACKGROUND AND AIM: Many multilevel logistic regression analyses of "neighbourhood and health" focus on interpreting measures of associations (e.g., odds ratio, OR). In contrast, multilevel analysis of variance is rarely considered. We propose an original stepwise analytical approach that disting......BACKGROUND AND AIM: Many multilevel logistic regression analyses of "neighbourhood and health" focus on interpreting measures of associations (e.g., odds ratio, OR). In contrast, multilevel analysis of variance is rarely considered. We propose an original stepwise analytical approach...

  18. The role of poverty rate and racial distribution in the geographic clustering of breast cancer survival among older women: a geographic and multilevel analysis.

    Science.gov (United States)

    Schootman, Mario; Jeffe, Donna B; Lian, Min; Gillanders, William E; Aft, Rebecca

    2009-03-01

    The authors examined disparities in survival among women aged 66 years or older in association with census-tract-level poverty rate, racial distribution, and individual-level factors, including patient-, treatment-, and tumor-related factors, utilization of medical care, and mammography use. They used linked data from the 1992-1999 Surveillance, Epidemiology, and End Results (SEER) programs, 1991-1999 Medicare claims, and the 1990 US Census. A geographic information system and advanced statistics identified areas of increased or reduced breast cancer survival and possible reasons for geographic variation in survival in 2 of the 5 SEER areas studied. In the Detroit, Michigan, area, one geographic cluster of shorter-than-expected breast cancer survival was identified (hazard ratio (HR) = 1.60). An additional area where survival was longer than expected approached statistical significance (HR = 0.4; P = 0.056). In the Atlanta, Georgia, area, one cluster of shorter- (HR = 1.81) and one cluster of longer-than-expected (HR = 0.72) breast cancer survival were identified. Stage at diagnosis and census-tract poverty (and patient's race in Atlanta) explained the geographic variation in breast cancer survival. No geographic clusters were identified in the 3 other SEER programs. Interventions to reduce late-stage breast cancer, focusing on areas of high poverty and targeting African Americans, may reduce disparities in breast cancer survival in the Detroit and Atlanta areas.

  19. A multilevel study of the determinants of area-level inequalities in colorectal cancer survival

    Directory of Open Access Journals (Sweden)

    Turrell Gavin

    2010-01-01

    Full Text Available Abstract Background In Australia, associations between geographic remoteness, socioeconomic disadvantage, and colorectal cancer (CRC survival show that survival rates are lowest among residents of geographically remote regions and those living in disadvantaged areas. At present we know very little about the reasons for these inequalities, hence our capacity to intervene to reduce the inequalities is limited. Methods/Design This study, the first of its type in Australia, examines the association between CRC survival and key area- and individual-level factors. Specifically, we will use a multilevel framework to investigate the possible determinants of area- and individual-level inequalities in CRC survival and quantify the relative contribution of geographic remoteness, socioeconomic and demographic factors, disease stage, and access to diagnostic and treatment services, to these inequalities. The multilevel analysis will be based on survival data relating to people diagnosed with CRC in Queensland between 1996 and 2005 (n = 22,723 from the Queensland Cancer Registry (QCR, area-level data from other data custodians such as the Australian Bureau of Statistics, and individual-level data from the QCR (including extracting stage from pathology records and Queensland Hospitals. For a subset of this period (2003 and 2004 we will utilise more detailed, individual-level data (n = 1,966 covering a greater range of risk factors from a concurrent research study. Geo-coding and spatial technology will be used to calculate road travel distances from patients' residence to treatment centres. The analyses will be conducted using a multilevel Cox proportional hazards model with Level 1 comprising individual-level factors (e.g. occupation and level 2 area-level indicators of remoteness and area socioeconomic disadvantage. Discussion This study focuses on the health inequalities for rural and disadvantaged populations that have often been documented but poorly

  20. Power analysis of trials with multilevel data

    CERN Document Server

    Moerbeek, Mirjam

    2015-01-01

    Power Analysis of Trials with Multilevel Data covers using power and sample size calculations to design trials that involve nested data structures. The book gives a thorough overview of power analysis that details terminology and notation, outlines key concepts of statistical power and power analysis, and explains why they are necessary in trial design. It guides you in performing power calculations with hierarchical data, which enables more effective trial design.The authors are leading experts in the field who recognize that power analysis has attracted attention from applied statisticians i

  1. Multilevel sparse functional principal component analysis.

    Science.gov (United States)

    Di, Chongzhi; Crainiceanu, Ciprian M; Jank, Wolfgang S

    2014-01-29

    We consider analysis of sparsely sampled multilevel functional data, where the basic observational unit is a function and data have a natural hierarchy of basic units. An example is when functions are recorded at multiple visits for each subject. Multilevel functional principal component analysis (MFPCA; Di et al. 2009) was proposed for such data when functions are densely recorded. Here we consider the case when functions are sparsely sampled and may contain only a few observations per function. We exploit the multilevel structure of covariance operators and achieve data reduction by principal component decompositions at both between and within subject levels. We address inherent methodological differences in the sparse sampling context to: 1) estimate the covariance operators; 2) estimate the functional principal component scores; 3) predict the underlying curves. Through simulations the proposed method is able to discover dominating modes of variations and reconstruct underlying curves well even in sparse settings. Our approach is illustrated by two applications, the Sleep Heart Health Study and eBay auctions.

  2. Multilevel analysis in road safety research.

    Science.gov (United States)

    Dupont, Emmanuelle; Papadimitriou, Eleonora; Martensen, Heike; Yannis, George

    2013-11-01

    Hierarchical structures in road safety data are receiving increasing attention in the literature and multilevel (ML) models are proposed for appropriately handling the resulting dependences among the observations. However, so far no empirical synthesis exists of the actual added value of ML modelling techniques as compared to other modelling approaches. This paper summarizes the statistical and conceptual background and motivations for multilevel analyses in road safety research. It then provides a review of several ML analyses applied to aggregate and disaggregate (accident) data. In each case, the relevance of ML modelling techniques is assessed by examining whether ML model formulations (i) allow improving the fit of the model to the data, (ii) allow identifying and explaining random variation at specific levels of the hierarchy considered, and (iii) yield different (more correct) conclusions than single-level model formulations with respect to the significance of the parameter estimates. The evidence reviewed offers different conclusions depending on whether the analysis concerns aggregate data or disaggregate data. In the first case, the application of ML analysis techniques appears straightforward and relevant. The studies based on disaggregate accident data, on the other hand, offer mixed findings: computational problems can be encountered, and ML applications are not systematically necessary. The general recommendation concerning disaggregate accident data is to proceed to a preliminary investigation of the necessity of ML analyses and of the additional information to be expected from their application.

  3. Closed Loop Analysis of Multilevel Inverter fed Drives

    Directory of Open Access Journals (Sweden)

    Bharath VS

    2014-05-01

    Full Text Available This paper deals with the simulation and implementation of multilevel inverter for drives application. Here the focuses will be on improving the efficiency of the multilevel inverter and quality of output voltage waveform. The circuit is developed towards high efficiency, high performance, and low cost, simple control scheme. Harmonics Elimination were implemented to reduce the Total Harmonics Distortion (THD value which is achieved by selecting appropriate switching angles. In this paper to determine the performance of rectifier, steady state analysis is done.  Furthermore, the merits of multilevel inverter topology are inherited.Closed loop control is done to analysis the stability of the system.

  4. A multilevel analysis of intercompany claim counts

    NARCIS (Netherlands)

    Antonio, K.; Frees, E.W.; Valdez, E.A.

    2009-01-01

    In this paper, we use multilevel models to analyze data on claim counts provided by the General Insurance Association of Singapore, an organization consisting of most of the general insurers in Singapore. Our data comes from the financial records of automobile insurance policies followed over a peri

  5. A multilevel analysis of intercompany claim counts

    NARCIS (Netherlands)

    Antonio, K.; Frees, E.W.; Valdez, E.A.

    2009-01-01

    In this paper, we use multilevel models to analyze data on claim counts provided by the General Insurance Association of Singapore, an organization consisting of most of the general insurers in Singapore. Our data comes from the financial records of automobile insurance policies followed over a peri

  6. Survival analysis models and applications

    CERN Document Server

    Liu, Xian

    2012-01-01

    Survival analysis concerns sequential occurrences of events governed by probabilistic laws.  Recent decades have witnessed many applications of survival analysis in various disciplines. This book introduces both classic survival models and theories along with newly developed techniques. Readers will learn how to perform analysis of survival data by following numerous empirical illustrations in SAS. Survival Analysis: Models and Applications: Presents basic techniques before leading onto some of the most advanced topics in survival analysis.Assumes only a minimal knowledge of SAS whilst enablin

  7. Help Seeking in Online Collaborative Groupwork: A Multilevel Analysis

    Science.gov (United States)

    Du, Jianxia; Xu, Jianzhong; Fan, Xitao

    2015-01-01

    This study examined predictive models for students' help seeking in the context of online collaborative groupwork. Results from multilevel analysis revealed that most of the variance in help seeking was at the individual student level, and multiple variables at the individual level were predictive of help-seeking behaviour. Help seeking was…

  8. Illustration of a Multilevel Model for Meta-Analysis

    Science.gov (United States)

    de la Torre, Jimmy; Camilli, Gregory; Vargas, Sadako; Vernon, R. Fox

    2007-01-01

    In this article, the authors present a multilevel (or hierarchical linear) model that illustrates issues in the application of the model to data from meta-analytic studies. In doing so, several issues are discussed that typically arise in the course of a meta-analysis. These include the presence of non-zero between-study variability, how multiple…

  9. Help Seeking in Online Collaborative Groupwork: A Multilevel Analysis

    Science.gov (United States)

    Du, Jianxia; Xu, Jianzhong; Fan, Xitao

    2015-01-01

    This study examined predictive models for students' help seeking in the context of online collaborative groupwork. Results from multilevel analysis revealed that most of the variance in help seeking was at the individual student level, and multiple variables at the individual level were predictive of help-seeking behaviour. Help seeking was…

  10. Applied survival analysis using R

    CERN Document Server

    Moore, Dirk F

    2016-01-01

    Applied Survival Analysis Using R covers the main principles of survival analysis, gives examples of how it is applied, and teaches how to put those principles to use to analyze data using R as a vehicle. Survival data, where the primary outcome is time to a specific event, arise in many areas of biomedical research, including clinical trials, epidemiological studies, and studies of animals. Many survival methods are extensions of techniques used in linear regression and categorical data, while other aspects of this field are unique to survival data. This text employs numerous actual examples to illustrate survival curve estimation, comparison of survivals of different groups, proper accounting for censoring and truncation, model variable selection, and residual analysis. Because explaining survival analysis requires more advanced mathematics than many other statistical topics, this book is organized with basic concepts and most frequently used procedures covered in earlier chapters, with more advanced topics...

  11. Reliability estimation in a multilevel confirmatory factor analysis framework.

    Science.gov (United States)

    Geldhof, G John; Preacher, Kristopher J; Zyphur, Michael J

    2014-03-01

    Scales with varying degrees of measurement reliability are often used in the context of multistage sampling, where variance exists at multiple levels of analysis (e.g., individual and group). Because methodological guidance on assessing and reporting reliability at multiple levels of analysis is currently lacking, we discuss the importance of examining level-specific reliability. We present a simulation study and an applied example showing different methods for estimating multilevel reliability using multilevel confirmatory factor analysis and provide supporting Mplus program code. We conclude that (a) single-level estimates will not reflect a scale's actual reliability unless reliability is identical at each level of analysis, (b) 2-level alpha and composite reliability (omega) perform relatively well in most settings, (c) estimates of maximal reliability (H) were more biased when estimated using multilevel data than either alpha or omega, and (d) small cluster size can lead to overestimates of reliability at the between level of analysis. We also show that Monte Carlo confidence intervals and Bayesian credible intervals closely reflect the sampling distribution of reliability estimates under most conditions. We discuss the estimation of credible intervals using Mplus and provide R code for computing Monte Carlo confidence intervals.

  12. Synchronization analysis on cascaded multilevel converters with distributed control

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Cascaded multilevel converters built with integrated modules have many advantages such as increased power density,flexible distributed control, multi-functionality, increased reliability and short design cycles. However, the system performance will be affected due to the synchronization errors among each integrated modules. This paper analyzes the impact of the three kinds of synchronization errors on the whole system performance, as well as detailed synchronization implementation. Some valuable conclusions are derived from the theoretical analysis, simulations and experimental results.

  13. Thermal and Efficiency Analysis of Five-Level Multilevel-Clamped Multilevel Converter Considering Grid Codes

    DEFF Research Database (Denmark)

    Ma, Ke; Muñoz-Aguilar, R. S.; Rodriguez, Pedro;

    2014-01-01

    In this paper, a five-level multilevel-clamped multilevel converter (5L- MLC2) topology is analyzed based on a typical grid integration application for renewable energy system. The loss and thermal distributions of the power devices in different switching legs are investigated and illustrated und...

  14. International students' enrollment in IPTA by using multilevel analysis

    Science.gov (United States)

    Wai, Phoong Seuk; Ismail, Mohd Tahir; Karim, Samsul Ariffin Abdul

    2012-09-01

    The increases of demand on knowledge-based and production-based market force the growth of higher education. International students' enrollment contributes to economic growth and increase country's income, university reputation and name; promote the competitive of education and training markets. This paper used multilevel analysis to study the international students' enrollment in Malaysia public university. Student's background variables and institution background variables were study in this paper and the relationship among them also been investigated. Result shows that institution type is a significance factor on international students' enrollment in Malaysia public university.

  15. Detecting bots using multi-level traffic analysis

    DEFF Research Database (Denmark)

    Stevanovic, Matija; Pedersen, Jens Myrup

    2016-01-01

    Botnets, as networks of compromised “zombie” computers, represent one of the most serious security threats on the Internet today. This paper explores how machines compromised with bot malware can be identified at local and enterprise networks in accurate and time-efficient manner. The paper...... introduces a novel multi-level botnet detection approach that performs network traffic analysis of three protocols widely considered as the main carriers of botnet Command and Control (C&C) and attack traffic, i.e. TCP, UDP and DNS. The proposed method relies on supervised machine learning for identifying...

  16. Social capital and mental health in Japan: a multilevel analysis.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Hamano

    Full Text Available BACKGROUND: A national cross-sectional survey was conducted in Japan. This is because the growing recognition of the social determinants of health has stimulated research on social capital and mental health. In recent years, systematic reviews have found that social capital may be a useful factor in the prevention of mental illness. Despite these studies, evidence on the association between social capital and mental health is limited as there have been few empirical discussions that adopt a multilevel framework to assess whether social capital at the ecological level is associated with individual mental health. The aim of this study was to use the multilevel approach to investigate the association between neighborhood social capital and mental health after taking into account potential individual confounders. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a multilevel analysis on 5,956 individuals nested within 199 neighborhoods. The outcome variable of self-reported mental health was measured by the one dimension of SF-36 and was summed to calculate a score ranging from 0 to 100. This study showed that high levels of cognitive social capital, measured by trust (regression coefficient = 9.56, and high levels of structural social capital, measured by membership in sports, recreation, hobby, or cultural groups (regression coefficient = 8.72, were associated with better mental health after adjusting for age, sex, household income, and educational attainment. Furthermore, after adjusting for social capital perceptions at the individual level, we found that the association between social capital and mental health also remained. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that both cognitive and structural social capital at the ecological level may influence mental health, even after adjusting for individual potential confounders including social capital perceptions. Promoting social capital may contribute to enhancing the mental health of

  17. Coordinating sentence composition with error correction: A multilevel analysis

    Directory of Open Access Journals (Sweden)

    Van Waes, L.

    2011-01-01

    Full Text Available Error analysis involves detecting and correcting discrepancies between the 'text produced so far' (TPSF and the writer's mental representation of what the text should be. While many factors determine the choice of strategy, cognitive effort is a major contributor to this choice. This research shows how cognitive effort during error analysis affects strategy choice and success as measured by a series of online text production measures. We hypothesize that error correction with speech recognition software differs from error correction with keyboard for two reasons. Speech produces auditory commands and, consequently, different error types. The study reported on here measured the effects of (1 mode of presentation (auditory or visual-tactile, (2 error span, whether the error spans more or less than two characters, and (3 lexicality, whether the text error comprises an existing word. A multilevel analysis was conducted to take into account the hierarchical nature of these data. For each variable (interference reaction time, preparation time, production time, immediacy of error correction, and accuracy of error correction, multilevel regression models are presented. As such, we take into account possible disturbing person characteristics while testing the effect of the different conditions and error types at the sentence level.The results show that writers delay error correction more often when the TPSF is read out aloud first. The auditory property of speech seems to free resources for the primary task of writing, i.e. text production. Moreover, the results show that large errors in the TPSF require more cognitive effort, and are solved with a higher accuracy than small errors. The latter also holds for the correction of small errors that result in non-existing words.

  18. Frailty Models in Survival Analysis

    CERN Document Server

    Wienke, Andreas

    2010-01-01

    The concept of frailty offers a convenient way to introduce unobserved heterogeneity and associations into models for survival data. In its simplest form, frailty is an unobserved random proportionality factor that modifies the hazard function of an individual or a group of related individuals. "Frailty Models in Survival Analysis" presents a comprehensive overview of the fundamental approaches in the area of frailty models. The book extensively explores how univariate frailty models can represent unobserved heterogeneity. It also emphasizes correlated frailty models as extensions of

  19. Multilevel structural equation models for assessing moderation within and across levels of analysis.

    Science.gov (United States)

    Preacher, Kristopher J; Zhang, Zhen; Zyphur, Michael J

    2016-06-01

    Social scientists are increasingly interested in multilevel hypotheses, data, and statistical models as well as moderation or interactions among predictors. The result is a focus on hypotheses and tests of multilevel moderation within and across levels of analysis. Unfortunately, existing approaches to multilevel moderation have a variety of shortcomings, including conflated effects across levels of analysis and bias due to using observed cluster averages instead of latent variables (i.e., "random intercepts") to represent higher-level constructs. To overcome these problems and elucidate the nature of multilevel moderation effects, we introduce a multilevel structural equation modeling (MSEM) logic that clarifies the nature of the problems with existing practices and remedies them with latent variable interactions. This remedy uses random coefficients and/or latent moderated structural equations (LMS) for unbiased tests of multilevel moderation. We describe our approach and provide an example using the publicly available High School and Beyond data with Mplus syntax in Appendix. Our MSEM method eliminates problems of conflated multilevel effects and reduces bias in parameter estimates while offering a coherent framework for conceptualizing and testing multilevel moderation effects. (PsycINFO Database Record

  20. Multi-level segment analysis: definition and applications in turbulence

    Science.gov (United States)

    Wang, Lipo

    2015-11-01

    The interaction of different scales is among the most interesting and challenging features in turbulence research. Existing approaches used for scaling analysis such as structure-function and Fourier spectrum method have their respective limitations, for instance scale mixing, i.e. the so-called infrared and ultraviolet effects. For a given function, by specifying different window sizes, the local extremal point set will be different. Such window size dependent feature indicates multi-scale statistics. A new method, multi-level segment analysis (MSA) based on the local extrema statistics, has been developed. The part of the function between two adjacent extremal points is defined as a segment, which is characterized by the functional difference and scale difference. The structure function can be differently derived from these characteristic parameters. Data test results show that MSA can successfully reveal different scaling regimes in turbulence systems such as Lagrangian and two-dimensional turbulence, which have been remaining controversial in turbulence research. In principle MSA can generally be extended for various analyses.

  1. Multilevel analysis of elastic morphology: The mantis shrimp's spring.

    Science.gov (United States)

    Rosario, M V; Patek, S N

    2015-09-01

    Spring systems, whether natural or engineered, are composed of compliant and rigid regions. Biological springs are often similar to monolithic structures that distribute compliance and rigidity across the whole system. For example, to confer different amounts of compliance in distinct regions within a single structure, biological systems typically vary regional morphology through thickening or elongation. Here, we analyze the monolithic spring in mantis shrimp (Stomatopoda) raptorial appendages to rapidly acquire or process prey. We quantified the shape of cross-sections of the merus segment of the raptorial appendage. We also examined specific regions of the merus that are hypothesized to either store elastic energy or provide structural support to permit energy storage in other regions of the system. We found that while all mantis shrimp contain thicker ventral bars in distal cross-sections, differences in thickness are more pronounced in high-impact "smasher" mantis shrimp than in the slower-striking "spearer" mantis shrimp. We also found that spearer cross-sections are more circular while those of smashers are more eccentric with elongation along the dorso-ventral axis. The results suggest that the regional thickening of ventral bars provides structural support for resisting spring compression and also reduces flexural stiffness along the system's long axis. This multilevel morphological analysis offers a foundation for understanding the evolution and mechanics of monolithic systems in biology. © 2015 Wiley Periodicals, Inc.

  2. Implementation and analysis of an adaptive multilevel Monte Carlo algorithm

    KAUST Repository

    Hoel, Hakon

    2014-01-01

    We present an adaptive multilevel Monte Carlo (MLMC) method for weak approximations of solutions to Itô stochastic dierential equations (SDE). The work [11] proposed and analyzed an MLMC method based on a hierarchy of uniform time discretizations and control variates to reduce the computational effort required by a single level Euler-Maruyama Monte Carlo method from O(TOL-3) to O(TOL-2 log(TOL-1)2) for a mean square error of O(TOL2). Later, the work [17] presented an MLMC method using a hierarchy of adaptively re ned, non-uniform time discretizations, and, as such, it may be considered a generalization of the uniform time discretizationMLMC method. This work improves the adaptiveMLMC algorithms presented in [17] and it also provides mathematical analysis of the improved algorithms. In particular, we show that under some assumptions our adaptive MLMC algorithms are asymptotically accurate and essentially have the correct complexity but with improved control of the complexity constant factor in the asymptotic analysis. Numerical tests include one case with singular drift and one with stopped diusion, where the complexity of a uniform single level method is O(TOL-4). For both these cases the results con rm the theory, exhibiting savings in the computational cost for achieving the accuracy O(TOL) from O(TOL-3) for the adaptive single level algorithm to essentially O(TOL-2 log(TOL-1)2) for the adaptive MLMC algorithm. © 2014 by Walter de Gruyter Berlin/Boston 2014.

  3. Survival analysis of aging aircraft

    Science.gov (United States)

    Benavides, Samuel

    This study pushes systems engineering of aging aircraft beyond the boundaries of empirical and deterministic modeling by making a sharp break with the traditional laboratory-derived corrosion prediction algorithms that have shrouded real-world failures of aircraft structure. At the heart of this problem is the aeronautical industry's inability to be forthcoming in an accurate model that predicts corrosion failures in aircraft in spite of advances in corrosion algorithms or improvements in simulation and modeling. The struggle to develop accurate corrosion probabilistic models stems from a multitude of real-world interacting variables that synergistically influence corrosion in convoluted and complex ways. This dissertation, in essence, offers a statistical framework for the analysis of structural airframe corrosion failure by utilizing real-world data while considering the effects of interacting corrosion variables. This study injects realism into corrosion failures of aging aircraft systems by accomplishing four major goals related to the conceptual and methodological framework of corrosion modeling. First, this work connects corrosion modeling from the traditional, laboratory derived algorithms to corrosion failures in actual operating aircraft. This work augments physics-based modeling by examining the many confounding and interacting variables, such as environmental, geographical and operational, that impact failure of airframe structure. Examined through the lens of censored failure data from aircraft flying in a maritime environment, this study enhances the understanding between the triad of the theoretical, laboratory and real-world corrosion. Secondly, this study explores the importation and successful application of an advanced biomedical statistical tool---survival analysis---to model censored corrosion failure data. This well-grounded statistical methodology is inverted from a methodology that analyzes survival to one that examines failures. Third, this

  4. A multilevel excess hazard model to estimate net survival on hierarchical data allowing for non-linear and non-proportional effects of covariates.

    Science.gov (United States)

    Charvat, Hadrien; Remontet, Laurent; Bossard, Nadine; Roche, Laurent; Dejardin, Olivier; Rachet, Bernard; Launoy, Guy; Belot, Aurélien

    2016-08-15

    The excess hazard regression model is an approach developed for the analysis of cancer registry data to estimate net survival, that is, the survival of cancer patients that would be observed if cancer was the only cause of death. Cancer registry data typically possess a hierarchical structure: individuals from the same geographical unit share common characteristics such as proximity to a large hospital that may influence access to and quality of health care, so that their survival times might be correlated. As a consequence, correct statistical inference regarding the estimation of net survival and the effect of covariates should take this hierarchical structure into account. It becomes particularly important as many studies in cancer epidemiology aim at studying the effect on the excess mortality hazard of variables, such as deprivation indexes, often available only at the ecological level rather than at the individual level. We developed here an approach to fit a flexible excess hazard model including a random effect to describe the unobserved heterogeneity existing between different clusters of individuals, and with the possibility to estimate non-linear and time-dependent effects of covariates. We demonstrated the overall good performance of the proposed approach in a simulation study that assessed the impact on parameter estimates of the number of clusters, their size and their level of unbalance. We then used this multilevel model to describe the effect of a deprivation index defined at the geographical level on the excess mortality hazard of patients diagnosed with cancer of the oral cavity. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Multilevel Analysis Methods for Partially Nested Cluster Randomized Trials

    Science.gov (United States)

    Sanders, Elizabeth A.

    2011-01-01

    This paper explores multilevel modeling approaches for 2-group randomized experiments in which a treatment condition involving clusters of individuals is compared to a control condition involving only ungrouped individuals, otherwise known as partially nested cluster randomized designs (PNCRTs). Strategies for comparing groups from a PNCRT in the…

  6. The Readability of Malaysian English Children Books: A Multilevel Analysis

    Directory of Open Access Journals (Sweden)

    Adlina Ismail

    2016-11-01

    Full Text Available These days, there are more English books for children published by local publishers in Malaysia. It is a positive development because the books will be more accessible to the children. However, the books have never been studied and evaluated in depth yet. One important factor in assessing reading materials is readability. Readability determines whether a text is easy or difficult to understand and a balanced mix of both can promote learning and language development. Various researchers mentioned a multilevel framework of discourse that any language assessment on a text should take into account. The levels that were proposed were word, syntax, textbase, situation model and genre and rhetorical structures. Traditional readability measures such as Flesh Reading Ease Formula, Gunning Readability Index, Fog Count, and Fry Grade Level are not able to address the multilevel because they are based on shallow variables. In contrast, Coh-metrix TERA provided five indices that are correlated to grade level and aligned to the multilevel framework. This study analyzed ten Malaysian English chapter books for children using this Coh-metrix TERA. The result revealed that the Malaysian English children books were easy in shallow level but there was a possible difficulty in textbase and situation model level because of the lack of cohesion. In conclusion, more attention should be given on deeper level of text rather than just word and syntax level. Keywords: Readability, assessment of reading materials, children books, Coh-Metrix

  7. Short Term Survival after Admission for Heart Failure in Sweden: Applying Multilevel Analyses of Discriminatory Accuracy to Evaluate Institutional Performance.

    Directory of Open Access Journals (Sweden)

    Nermin Ghith

    Full Text Available Hospital performance is frequently evaluated by analyzing differences between hospital averages in some quality indicators. The results are often expressed as quality charts of hospital variance (e.g., league tables, funnel plots. However, those analyses seldom consider patients heterogeneity around averages, which is of fundamental relevance for a correct evaluation. Therefore, we apply an innovative methodology based on measures of components of variance and discriminatory accuracy to analyze 30-day mortality after hospital discharge with a diagnosis of Heart Failure (HF in Sweden.We analyzed 36,943 patients aged 45-80 treated in 565 wards at 71 hospitals during 2007-2009. We applied single and multilevel logistic regression analyses to calculate the odds ratios and the area under the receiver-operating characteristic (AUC. We evaluated general hospital and ward effects by quantifying the intra-class correlation coefficient (ICC and the increment in the AUC obtained by adding random effects in a multilevel regression analysis (MLRA. Finally, the Odds Ratios (ORs for specific ward and hospital characteristics were interpreted jointly with the proportional change in variance (PCV and the proportion of ORs in the opposite direction (POOR.Overall, the average 30-day mortality was 9%. Using only patient information on age and previous hospitalizations for different diseases we obtained an AUC = 0.727. This value was almost unchanged when adding sex, country of birth as well as hospitals and wards levels. Average mortality was higher in small wards and municipal hospitals but the POOR values were 15% and 16% respectively.Swedish wards and hospitals in general performed homogeneously well, resulting in a low 30-day mortality rate after HF. In our study, knowledge on a patient's previous hospitalizations was the best predictor of 30-day mortality, and this information did not improve by knowing the sex and country of birth of the patient or where the

  8. Evaluating Technical Efficiency of Nursing Care Using Data Envelopment Analysis and Multilevel Modeling.

    Science.gov (United States)

    Min, Ari; Park, Chang Gi; Scott, Linda D

    2016-05-23

    Data envelopment analysis (DEA) is an advantageous non-parametric technique for evaluating relative efficiency of performance. This article describes use of DEA to estimate technical efficiency of nursing care and demonstrates the benefits of using multilevel modeling to identify characteristics of efficient facilities in the second stage of analysis. Data were drawn from LTCFocUS.org, a secondary database including nursing home data from the Online Survey Certification and Reporting System and Minimum Data Set. In this example, 2,267 non-hospital-based nursing homes were evaluated. Use of DEA with nurse staffing levels as inputs and quality of care as outputs allowed estimation of the relative technical efficiency of nursing care in these facilities. In the second stage, multilevel modeling was applied to identify organizational factors contributing to technical efficiency. Use of multilevel modeling avoided biased estimation of findings for nested data and provided comprehensive information on differences in technical efficiency among counties and states.

  9. Friendship Dissolution Within Social Networks Modeled Through Multilevel Event History Analysis.

    Science.gov (United States)

    Dean, Danielle O; Bauer, Daniel J; Prinstein, Mitchell J

    2017-01-01

    A social network perspective can bring important insight into the processes that shape human behavior. Longitudinal social network data, measuring relations between individuals over time, has become increasingly common-as have the methods available to analyze such data. A friendship duration model utilizing discrete-time multilevel survival analysis with a multiple membership random effect structure is developed and applied here to study the processes leading to undirected friendship dissolution within a larger social network. While the modeling framework is introduced in terms of understanding friendship dissolution, it can be used to understand microlevel dynamics of a social network more generally. These models can be fit with standard generalized linear mixed-model software, after transforming the data to a pair-period data set. An empirical example highlights how the model can be applied to understand the processes leading to friendship dissolution between high school students, and a simulation study is used to test the use of the modeling framework under representative conditions that would be found in social network data. Advantages of the modeling framework are highlighted, and potential limitations and future directions are discussed.

  10. Community violence and urban childhood asthma: a multilevel analysis.

    Science.gov (United States)

    Sternthal, M J; Jun, H-J; Earls, F; Wright, R J

    2010-12-01

    We examined the association between community violence exposure and childhood asthma risk in a multilevel, multimethod, longitudinal study controlling for individual- and neighbourhood-level confounders and pathway variables. Analyses included 2,071 children aged 0-9 yrs at enrolment from the Project on Human Development in Chicago Neighborhoods. Multilevel logistic regression models estimated the likelihood of asthma, controlling for individual-level (child's age, sex, race/ethnicity, maternal asthma, socioeconomic status and family violence in the home) and neighbourhood-level confounders (concentrated disadvantage, collective efficacy and social disorder), and pathway variables (maternal smoking, breastfeeding). In adjusted analyses, medium (OR 1.60, 95% CI 1.17-2.19) and high levels (OR 1.56, 95% CI 1.12-2.18) of community violence were associated with increased asthma risk, relative to low levels. The increased asthma risk remained for African Americans when models included community violence and all other individual-level covariates, but attenuated to borderline nonsignificance when further adjusting for collective efficacy. Community violence is associated with asthma risk when controlling for individual- and neighborhood-level confounders. Neither community violence, nor the other individual-level factors, fully accounted for the excess asthma burden among African Americans. These data suggest that public health interventions outside the biomedical model may be needed to reduce asthma in disadvantaged populations.

  11. Harmonic Analysis of Seven and Nine Level Cascade Multilevel Inverter using Multi-Carrier PWM Technique

    Directory of Open Access Journals (Sweden)

    Chetanya Gupta

    2014-07-01

    Full Text Available The use of multilevel inverters has become popular in recent years for high-power applications. Multilevel Inverters are power converter systems composed by an array of power semiconductor sources that when properly connected and controlled can generate a multistep voltage waveform with variable and controllable frequency, phase and amplitude. This study deals with the comparison of a 7-level inverter with a 9-level inverter system; the voltage source inverters (VSI are modelled and simulated using MATLAB Simulink and the results are presented. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses. This research aims to extend the knowledge about the performance of different clamped multilevel inverter through harmonic analysis. Simulations results validate up to the mark performance of the mentioned topologies.

  12. Streamlined mean field variational Bayes for longitudinal and multilevel data analysis.

    Science.gov (United States)

    Lee, Cathy Yuen Yi; Wand, Matt P

    2016-07-01

    Streamlined mean field variational Bayes algorithms for efficient fitting and inference in large models for longitudinal and multilevel data analysis are obtained. The number of operations is linear in the number of groups at each level, which represents a two orders of magnitude improvement over the naïve approach. Storage requirements are also lessened considerably. We treat models for the Gaussian and binary response situations. Our algorithms allow the fastest ever approximate Bayesian analyses of arbitrarily large longitudinal and multilevel datasets, with little degradation in accuracy compared with Markov chain Monte Carlo. The modularity of mean field variational Bayes allows relatively simple extension to more complicated scenarios.

  13. Principles of multilevel analysis and its relevance to studies of antimicrobial resistance.

    Science.gov (United States)

    Vellinga, Akke; Bennett, Kathleen; Murphy, Andrew W; Cormican, Martin

    2012-10-01

    When studying antimicrobial resistance it is clear that individuals do not exist in isolation and are often clustered into groups. Data within groups are generally not independent, but standard statistical approaches assume independence of observations. When data are clustered (e.g. students in schools, patients in general practices, etc.) multilevel analysis can be used. The overall idea of multilevel analysis is that the clustering is taken into account in the analysis and provides additional information on the interactions between individuals and groups. The lowest level is often the individual and additional levels are formed by clustering in groups (the higher levels). This article introduces the principles behind multilevel modelling. The approach is to provide readers with sufficient information to understand outcomes in which this statistical technique is used, without expecting the reader to be able to perform such an analysis. As multilevel modelling can be seen as an extension of linear regression analysis, this is the starting point of the article. Other concepts and terms are introduced throughout, resulting in the explanation of the accompanying article on antimicrobial prescribing and resistance in Irish general practice (Vellinga A, Tansey S, Hanahoe B et al. J Antimicrob Chemother 2012; 67: 2523-30).

  14. Documenting Attitudes toward Undocumented Immigrant Access to Public Education: A Multilevel Analysis

    Science.gov (United States)

    Herrera, Felisha A.; Garibay, Juan C.; Garcia, Gina A.; Johnston, Marc P.

    2013-01-01

    This study investigates how students' views toward undocumented immigrants' access to public education change during college. A multilevel analysis among a national sample of 12,388 undergraduates, drawn from the Cooperative Institutional Research Program's (CIRP) Freshman Survey and College Senior Survey, revealed that significant…

  15. Multilevel Factor Analysis by Model Segregation: New Applications for Robust Test Statistics

    Science.gov (United States)

    Schweig, Jonathan

    2014-01-01

    Measures of classroom environments have become central to policy efforts that assess school and teacher quality. This has sparked a wide interest in using multilevel factor analysis to test measurement hypotheses about classroom-level variables. One approach partitions the total covariance matrix and tests models separately on the…

  16. Brief Report: Multilevel Analysis of School Smoking Policy and Pupil Smoking Behaviour in Wales

    Science.gov (United States)

    Wiium, Nora; Burgess, Stephen; Moore, Laurence

    2011-01-01

    A multilevel analysis of cross-sectional data from a survey involving 1941 pupils (in grades 10 and 11) and policy indicators developed from interviews with staff from 45 secondary schools in Wales examined the hypotheses that pupil smoking prevalence would be associated with: restrictive staff and pupil smoking policies; dissemination of school…

  17. Individual-Level Influences on Perceptions of Neighborhood Disorder: A Multilevel Analysis

    Science.gov (United States)

    Latkin, Carl A.; German, Danielle; Hua, Wei; Curry, Aaron D.

    2009-01-01

    Health outcomes are associated with aggregate neighborhood measures and individual neighborhood perceptions. In this study, the authors sought to delineate individual, social network, and spatial factors that may influence perceptions of neighborhood disorder. Multilevel regression analysis showed that neighborhood perceptions were more negative…

  18. The multilevel p2 model : A random effects model for the analysis of multiple social networks

    NARCIS (Netherlands)

    Zijlstra, B.J.H.; van Duijn, M.A.J.; Snijders, T.A.B.

    2006-01-01

    The p2 model is a random effects model with covariates for the analysis of binary directed social network data coming from a single observation of a social network. Here, a multilevel variant of the p2 model is proposed for the case of multiple observations of social networks, for example, in a samp

  19. Explaining Differences in Civic Knowledge: Multi-Level Regression Analysis of Student Data from 27 Countries.

    Science.gov (United States)

    Schulz, Wolfram

    Differences in student knowledge about democracy, institutions, and citizenship and students skills in interpreting political communication were studied through multilevel regression analysis of results from the second International Education Association (IEA) Study. This study provides data on 14-year-old students from 28 countries in Europe,…

  20. Multilevel Factor Analysis and Structural Equation Modeling of Daily Diary Coping Data: Modeling Trait and State Variation

    Science.gov (United States)

    Roesch, Scott C.; Aldridge, Arianna A.; Stocking, Stephanie N.; Villodas, Feion; Leung, Queenie; Bartley, Carrie E.; Black, Lisa J.

    2010-01-01

    This study used multilevel modeling of daily diary data to model within-person (state) and between-person (trait) components of coping variables. This application included the introduction of multilevel factor analysis (MFA) and a comparison of the predictive ability of these trait/state factors. Daily diary data were collected on a large (n =…

  1. Empirical likelihood method in survival analysis

    CERN Document Server

    Zhou, Mai

    2015-01-01

    Add the Empirical Likelihood to Your Nonparametric ToolboxEmpirical Likelihood Method in Survival Analysis explains how to use the empirical likelihood method for right censored survival data. The author uses R for calculating empirical likelihood and includes many worked out examples with the associated R code. The datasets and code are available for download on his website and CRAN.The book focuses on all the standard survival analysis topics treated with empirical likelihood, including hazard functions, cumulative distribution functions, analysis of the Cox model, and computation of empiric

  2. Generalized multilevel function-on-scalar regression and principal component analysis.

    Science.gov (United States)

    Goldsmith, Jeff; Zipunnikov, Vadim; Schrack, Jennifer

    2015-06-01

    This manuscript considers regression models for generalized, multilevel functional responses: functions are generalized in that they follow an exponential family distribution and multilevel in that they are clustered within groups or subjects. This data structure is increasingly common across scientific domains and is exemplified by our motivating example, in which binary curves indicating physical activity or inactivity are observed for nearly 600 subjects over 5 days. We use a generalized linear model to incorporate scalar covariates into the mean structure, and decompose subject-specific and subject-day-specific deviations using multilevel functional principal components analysis. Thus, functional fixed effects are estimated while accounting for within-function and within-subject correlations, and major directions of variability within and between subjects are identified. Fixed effect coefficient functions and principal component basis functions are estimated using penalized splines; model parameters are estimated in a Bayesian framework using Stan, a programming language that implements a Hamiltonian Monte Carlo sampler. Simulations designed to mimic the application have good estimation and inferential properties with reasonable computation times for moderate datasets, in both cross-sectional and multilevel scenarios; code is publicly available. In the application we identify effects of age and BMI on the time-specific change in probability of being active over a 24-hour period; in addition, the principal components analysis identifies the patterns of activity that distinguish subjects and days within subjects.

  3. Individual environmental concern in the world polity: A multilevel analysis.

    Science.gov (United States)

    Givens, Jennifer E; Jorgenson, Andrew K

    2013-03-01

    The authors assess the extent to which national-level integration in the world polity influences individual-level concern for the environment. While theoretically-derived propositions about such relationships have a deep history in comparative sociology, they-with few exceptions-remain untested. Consistent with past research, employed national-level measures of world polity integration include the relative presence of environmental international nongovernmental organizations (EINGOs) and the existence of environmental ministries. Results of multilevel analyses of individual-level environmental concern in 37 nations indicate that both forms of world polity integration increase the likelihood of individual-level environmental concern, net of other national-level factors and individual-level characteristics; although we find stronger support for the influence of EINGOs as a key variable indicating world polity connection. The findings provide unique support for world polity theory, suggesting that future research should consider how elements of world polity integration influence other forms of individual attitudes and behaviors. The results also highlight the importance in considering global and transnational factors when assessing the determinants of individual attitudes about the environment.

  4. Social capital and health in Kenya: A multilevel analysis.

    Science.gov (United States)

    Musalia, John

    2016-10-01

    Despite the acknowledgment that social capital is an important predictor of good health and overall well being in wealthy countries, little empirical research has been conducted in developing countries, particularly in Africa, to examine this relationship. This study examines the association between cognitive (trust) and structural (membership in organization) social capital on health at both the individual and contextual levels. Health was measured using answers to a subjective question on physical health and anxiety/worry suffered by individuals within the last 30 days. This study utilized Afrobarometer data collected in Kenya in 2005 to examine this relationship using multilevel logistic statistical modeling. Upon controlling for socioeconomic and demographic factors, social capital was found to be significantly associated with anxiety/worry and physical health in Kenya. Membership in organizations was associated with increased odds (OR = 1.34, 95%CI: 1.02-1.76) of physical health problems, while individual trust was associated with a 6% (OR = 0.94, 95%CI: 0.90-0.99) reduction in the likelihood of physical health problems. Conversely, generalized trust was associated with a 37% reduction in the odds (OR = 0.63, 95%CI: 0.40-0.99) of anxiety/worry, while individual trust was associated with a 5% reduction (OR = 0.95, 95%CI: 0.90-1.00) of anxiety/worry. With the exception of membership in an organization that exacerbates physical health, both individual level trust and generalized trust were associated with better health outcomes in Kenya. The availability of social organizations at the contextual level was associated with worsening anxiety/worry although the effect size was small. These results show that social capital, particularly trust, is a concept that can apply to different social and cultural contexts and can potentially be harnessed to improve health in settings that suffer from resource poverty.

  5. Thermal and efficiency analysis of five-level multi-level clamped multilevel converter considering grid codes

    DEFF Research Database (Denmark)

    Ma, Ke; Muñoz-Aguilar, S.; Rodriguez, P.;

    2012-01-01

    In this paper a five-level Multi-Clamped Multilevel Converter (5L-MLC2) topology is analyzed based on a typical grid integration application for renewable energy generation system. The loss and thermal distribution of the power devices in different switching legs are investigated and illustrated ...

  6. Pseudo-observations in survival analysis

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Perme, Maja Pohar

    2010-01-01

    We review recent work on the application of pseudo-observations in survival and event history analysis. This includes regression models for parameters like the survival function in a single point, the restricted mean survival time and transition or state occupation probabilities in multi......-state models, e.g. the competing risks cumulative incidence function. Graphical and numerical methods for assessing goodness-of-fit for hazard regression models and for the Fine-Gray model in competing risks studies based on pseudo-observations are also reviewed. Sensitivity to covariate-dependent censoring...... is studied. The methods are illustrated using a data set from bone marrow transplantation....

  7. Pseudo-observations in survival analysis.

    Science.gov (United States)

    Andersen, Per Kragh; Perme, Maja Pohar

    2010-02-01

    We review recent work on the application of pseudo-observations in survival and event history analysis. This includes regression models for parameters like the survival function in a single point, the restricted mean survival time and transition or state occupation probabilities in multi-state models, e.g. the competing risks cumulative incidence function. Graphical and numerical methods for assessing goodness-of-fit for hazard regression models and for the Fine-Gray model in competing risks studies based on pseudo-observations are also reviewed. Sensitivity to covariate-dependent censoring is studied. The methods are illustrated using a data set from bone marrow transplantation.

  8. Further analysis of multilevel Monte Carlo methods for elliptic PDEs with random coefficients

    OpenAIRE

    Teckentrup, A. L.; Scheichl, R.; Giles, M. B.; Ullmann, E

    2012-01-01

    We consider the application of multilevel Monte Carlo methods to elliptic PDEs with random coefficients. We focus on models of the random coefficient that lack uniform ellipticity and boundedness with respect to the random parameter, and that only have limited spatial regularity. We extend the finite element error analysis for this type of equation, carried out recently by Charrier, Scheichl and Teckentrup, to more difficult problems, posed on non--smooth domains and with discontinuities in t...

  9. Measuring the Effects of Trade Liberalization: Multilevel Analysis Tool for Agriculture

    OpenAIRE

    Gerard, Francoise; Marty, Isabelle; Lancon, Frederic; Versapuech, Marion

    1998-01-01

    This book is the product of the projects "Farmers' Strategies Regarding Agricultural Diversification" (1993-1995) and "Agricultural Diversification and Food Crop Trade: Their Implications to Agricultural Policies in Southeast Asia" (1994-1996), both supported by CIRAD and the Government of France. It describes the first project attempting to apply the MATA methodology in a country like Indonesia. As constructed, the Multilevel Analysis Tool for Agriculture is able to answer various policy que...

  10. Multiple Group Analysis in Multilevel Structural Equation Model Across Level 1 Groups.

    Science.gov (United States)

    Ryu, Ehri

    2015-01-01

    This article introduces and evaluates a procedure for conducting multiple group analysis in multilevel structural equation model across Level 1 groups (MG1-MSEM; Ryu, 2014). When group membership is at Level 1, multiple group analysis raises two issues that cannot be solved by a simple extension of the standard multiple group analysis in single-level structural equation model. First, the Level 2 data are not independent between Level 1 groups. Second, the standard procedure fails to take into account the dependency between members of different Level 1 groups within the same cluster. The MG1-MSEM approach provides solutions to these problems. In MG1-MSEM, the Level 1 mean structure is necessary to represent the differences between Level 1 groups within clusters. The Level 2 model is the same regardless of Level 1 group membership. A simulation study examined the performance of MUML (Muthén's maximum likelihood) estimation in MG1-MSEM. The MG1-MSEM approach is illustrated for both a multilevel path model and a multilevel factor model using empirical data sets.

  11. Multilevel Mixture Factor Models

    Science.gov (United States)

    Varriale, Roberta; Vermunt, Jeroen K.

    2012-01-01

    Factor analysis is a statistical method for describing the associations among sets of observed variables in terms of a small number of underlying continuous latent variables. Various authors have proposed multilevel extensions of the factor model for the analysis of data sets with a hierarchical structure. These Multilevel Factor Models (MFMs)…

  12. Understanding survival analysis: Kaplan-Meier estimate

    Science.gov (United States)

    Goel, Manish Kumar; Khanna, Pardeep; Kishore, Jugal

    2010-01-01

    Kaplan-Meier estimate is one of the best options to be used to measure the fraction of subjects living for a certain amount of time after treatment. In clinical trials or community trials, the effect of an intervention is assessed by measuring the number of subjects survived or saved after that intervention over a period of time. The time starting from a defined point to the occurrence of a given event, for example death is called as survival time and the analysis of group data as survival analysis. This can be affected by subjects under study that are uncooperative and refused to be remained in the study or when some of the subjects may not experience the event or death before the end of the study, although they would have experienced or died if observation continued, or we lose touch with them midway in the study. We label these situations as censored observations. The Kaplan-Meier estimate is the simplest way of computing the survival over time in spite of all these difficulties associated with subjects or situations. The survival curve can be created assuming various situations. It involves computing of probabilities of occurrence of event at a certain point of time and multiplying these successive probabilities by any earlier computed probabilities to get the final estimate. This can be calculated for two groups of subjects and also their statistical difference in the survivals. This can be used in Ayurveda research when they are comparing two drugs and looking for survival of subjects. PMID:21455458

  13. Missing values in multi-level simultaneous component analysis

    NARCIS (Netherlands)

    Josse, Julie; Timmerman, Marieke E.; Kiers, Henk A. L.

    2013-01-01

    Component analysis of data with missing values is often performed with algorithms of iterative imputation. However, this approach is prone to overfitting problems. As an alternative, Josse et al. (2009) proposed a regularized algorithm in the framework of Principal Component Analysis (PCA). Here we

  14. A Multilevel Nonlinear Profile Analysis Model for Dichotomous Data

    Science.gov (United States)

    Culpepper, Steven Andrew

    2009-01-01

    This study linked nonlinear profile analysis (NPA) of dichotomous responses with an existing family of item response theory models and generalized latent variable models (GLVM). The NPA method offers several benefits over previous internal profile analysis methods: (a) NPA is estimated with maximum likelihood in a GLVM framework rather than…

  15. Multi-level Bayesian safety analysis with unprocessed Automatic Vehicle Identification data for an urban expressway.

    Science.gov (United States)

    Shi, Qi; Abdel-Aty, Mohamed; Yu, Rongjie

    2016-03-01

    In traffic safety studies, crash frequency modeling of total crashes is the cornerstone before proceeding to more detailed safety evaluation. The relationship between crash occurrence and factors such as traffic flow and roadway geometric characteristics has been extensively explored for a better understanding of crash mechanisms. In this study, a multi-level Bayesian framework has been developed in an effort to identify the crash contributing factors on an urban expressway in the Central Florida area. Two types of traffic data from the Automatic Vehicle Identification system, which are the processed data capped at speed limit and the unprocessed data retaining the original speed were incorporated in the analysis along with road geometric information. The model framework was proposed to account for the hierarchical data structure and the heterogeneity among the traffic and roadway geometric data. Multi-level and random parameters models were constructed and compared with the Negative Binomial model under the Bayesian inference framework. Results showed that the unprocessed traffic data was superior. Both multi-level models and random parameters models outperformed the Negative Binomial model and the models with random parameters achieved the best model fitting. The contributing factors identified imply that on the urban expressway lower speed and higher speed variation could significantly increase the crash likelihood. Other geometric factors were significant including auxiliary lanes and horizontal curvature.

  16. Examining mutable reform options for urban schools with multilevel analysis in the National Educational Longitudinal Study:88

    Science.gov (United States)

    Roberts, John Kyle

    2000-11-01

    The present study examined the effects of science course taking and school urbanicity on students' science achievement levels. More specifically, this study analyzed the National Educational Longitudinal Study (NELS:88) with multilevel techniques to investigate mutable reform options for urban schools in the area of science achievement. This study provided a unique insight into current research because all analyses were conducted with both ordinary least squares regression (OLS) and multilevel modeling techniques. Results from the comparison of OLS and multilevel techniques showed little effect on either overestimation or underestimation between the OLS weighted sample and the multilevel analysis. Although the differences between these two analyses were small, the multilevel techniques were optimized when the differences between schools was largest. Results from the multilevel and weighted analyses produced large differences when compared against the unweighted analysis. The unweighted sample consistently overestimated the coefficients of slope for each of the predictor variables. Because of these findings, researchers should be strongly cautioned against interpreting analyses run with the NELS:88 dataset without a weighted sample or without multilevel techniques. The results from the multiple regression analysis in both multilevel modeling and weighted OLS indicated that students who had parents who attended a school event, were not afraid to ask questions in science class, spent more time on homework each week, did not attend a school where science was taught in a non-English language, and had parents who belonged to a parent/teacher organization scored higher in terms of student science achievement than did their urban counterparts who did not meet these qualifications. From these results, several recommendations were made for schools concerning ways they could improve science education, including fostering attitudes of inquiry in science, increasing the

  17. SURVIVAL ANALYSIS AND LENGTH-BIASED SAMPLING

    Directory of Open Access Journals (Sweden)

    Masoud Asgharian

    2010-12-01

    Full Text Available When survival data are colleted as part of a prevalent cohort study, the recruited cases have already experienced their initiating event. These prevalent cases are then followed for a fixed period of time at the end of which the subjects will either have failed or have been censored. When interests lies in estimating the survival distribution, from onset, of subjects with the disease, one must take into account that the survival times of the cases in a prevalent cohort study are left truncated. When it is possible to assume that there has not been any epidemic of the disease over the past period of time that covers the onset times of the subjects, one may assume that the underlying incidence process that generates the initiating event times is a stationary Poisson process. Under such assumption, the survival times of the recruited subjects are called “lengthbiased”. I discuss the challenges one is faced with in analyzing these type of data. To address the theoretical aspects of the work, I present asymptotic results for the NPMLE of the length-biased as well as the unbiased survival distribution. I also discuss estimating the unbiased survival function using only the follow-up time. This addresses the case that the onset times are either unknown or known with uncertainty. Some of our most recent work and open questions will be presented. These include some aspects of analysis of covariates, strong approximation, functional LIL and density estimation under length-biased sampling with right censoring. The results will be illustrated with survival data from patients with dementia, collected as part of the Canadian Study of Health and Aging (CSHA.

  18. Multilevel Latent Class Analysis: Parametric and Nonparametric Models

    Science.gov (United States)

    Finch, W. Holmes; French, Brian F.

    2014-01-01

    Latent class analysis is an analytic technique often used in educational and psychological research to identify meaningful groups of individuals within a larger heterogeneous population based on a set of variables. This technique is flexible, encompassing not only a static set of variables but also longitudinal data in the form of growth mixture…

  19. Multi-level governance-perspective on management of nuclear waste disposal. A comparative analysis

    Energy Technology Data Exchange (ETDEWEB)

    Brunnengraeber, Achim; Haefner, Daniel

    2015-07-01

    The primary aim of the project is to conduct a detailed social and political analysis of the preconditions for the development of an acceptable strategy for nuclear waste disposal in Germany. This includes the identification of stakeholders and their interests, responsibilities, value systems, views and expectations as well as paths for a constructive approach to dialogue and problem-solving. A focus of the research project will be an international comparative multi-level governance analysis of acceptance patterns and steering mechanisms for conflict resolution.

  20. Global multi-level analysis of the 'scientific food web'.

    Science.gov (United States)

    Mazloumian, Amin; Helbing, Dirk; Lozano, Sergi; Light, Robert P; Börner, Katy

    2013-01-01

    We introduce a network-based index analyzing excess scientific production and consumption to perform a comprehensive global analysis of scholarly knowledge production and diffusion on the level of continents, countries, and cities. Compared to measures of scientific production and consumption such as number of publications or citation rates, our network-based citation analysis offers a more differentiated picture of the 'ecosystem of science'. Quantifying knowledge flows between 2000 and 2009, we identify global sources and sinks of knowledge production. Our knowledge flow index reveals, where ideas are born and consumed, thereby defining a global 'scientific food web'. While Asia is quickly catching up in terms of publications and citation rates, we find that its dependence on knowledge consumption has further increased.

  1. Study of visualized simulation and analysis of nuclear fuel cycle system based on multilevel flow model

    Institute of Scientific and Technical Information of China (English)

    LIU Jing-Quan; YOSHIKAWA Hidekazu; ZHOU Yang-Ping

    2005-01-01

    Complex energy and environment system, especially nuclear fuel cycle system recently raised social concerns about the issues of economic competitiveness, environmental effect and nuclear proliferation. Only under the condition that those conflicting issues are gotten a consensus between stakeholders with different knowledge background, can nuclear power industry be continuingly developed. In this paper, a new analysis platform has been developed to help stakeholders to recognize and analyze various socio-technical issues in the nuclear fuel cycle system based on the functional modeling method named Multilevel Flow Models (MFM) according to the cognition theory of human being. Its character is that MFM models define a set of mass, energy and information flow structures on multiple levels of abstraction to describe the functional structure of a process system and its graphical symbol representation and the means-end and part-whole hierarchical flow structure to make the represented process easy to be understood. Based upon this methodology, a micro-process and a macro-process of nuclear fuel cycle system were selected to be simulated and some analysis processes such as economics analysis, environmental analysis and energy balance analysis related to those flows were also integrated to help stakeholders to understand the process of decision-making with the introduction of some new functions for the improved Multilevel Flow Models Studio, and finally the simple simulation such as spent fuel management process simulation and money flow of nuclear fuel cycle and its levelised cost analysis will be represented as feasible examples.

  2. Schools, parents, and youth violence: a multilevel, ecological analysis.

    Science.gov (United States)

    Brookmeyer, Kathryn A; Fanti, Kostas A; Henrich, Christopher C

    2006-12-01

    Using data from the National Longitudinal Study of Adolescent Health (Add Health), this study utilized an ecological approach to investigate the joint contribution of parents and schools on changes in violent behavior over time among a sample of 6,397 students (54% female) from 125 schools. This study examined the main and interactive effects of parent and school connectedness as buffers of violent behavior within a hierarchical linear model, focusing on both students and schools as the unit of analysis. Results show that students who feel more connected to their schools demonstrate reductions in violent behavior over time. On the school level, our findings suggest that school climate serves as a protective factor for student violent behavior. Finally, parent and school connectedness appear to work together to buffer adolescents from the effects of violence exposure on subsequent violent behavior.

  3. An Original Stepwise Multilevel Logistic Regression Analysis of Discriminatory Accuracy: The Case of Neighbourhoods and Health.

    Directory of Open Access Journals (Sweden)

    Juan Merlo

    Full Text Available Many multilevel logistic regression analyses of "neighbourhood and health" focus on interpreting measures of associations (e.g., odds ratio, OR. In contrast, multilevel analysis of variance is rarely considered. We propose an original stepwise analytical approach that distinguishes between "specific" (measures of association and "general" (measures of variance contextual effects. Performing two empirical examples we illustrate the methodology, interpret the results and discuss the implications of this kind of analysis in public health.We analyse 43,291 individuals residing in 218 neighbourhoods in the city of Malmö, Sweden in 2006. We study two individual outcomes (psychotropic drug use and choice of private vs. public general practitioner, GP for which the relative importance of neighbourhood as a source of individual variation differs substantially. In Step 1 of the analysis, we evaluate the OR and the area under the receiver operating characteristic (AUC curve for individual-level covariates (i.e., age, sex and individual low income. In Step 2, we assess general contextual effects using the AUC. Finally, in Step 3 the OR for a specific neighbourhood characteristic (i.e., neighbourhood income is interpreted jointly with the proportional change in variance (i.e., PCV and the proportion of ORs in the opposite direction (POOR statistics.For both outcomes, information on individual characteristics (Step 1 provide a low discriminatory accuracy (AUC = 0.616 for psychotropic drugs; = 0.600 for choosing a private GP. Accounting for neighbourhood of residence (Step 2 only improved the AUC for choosing a private GP (+0.295 units. High neighbourhood income (Step 3 was strongly associated to choosing a private GP (OR = 3.50 but the PCV was only 11% and the POOR 33%.Applying an innovative stepwise multilevel analysis, we observed that, in Malmö, the neighbourhood context per se had a negligible influence on individual use of psychotropic drugs, but

  4. Incomplete quality of life data in lung transplant research: comparing cross sectional, repeated measures ANOVA, and multi-level analysis

    Directory of Open Access Journals (Sweden)

    van der Bij Wim

    2005-09-01

    Full Text Available Abstract Background In longitudinal studies on Health Related Quality of Life (HRQL it frequently occurs that patients have one or more missing forms, which may cause bias, and reduce the sample size. Aims of the present study were to address the problem of missing data in the field of lung transplantation (LgTX and HRQL, to compare results obtained with different methods of analysis, and to show the value of each type of statistical method used to summarize data. Methods Results from cross-sectional analysis, repeated measures on complete cases (ANOVA, and a multi-level analysis were compared. The scores on the dimension 'energy' of the Nottingham Health Profile (NHP after transplantation were used to illustrate the differences between methods. Results Compared to repeated measures ANOVA, the cross-sectional and multi-level analysis included more patients, and allowed for a longer period of follow-up. In contrast to the cross sectional analyses, in the complete case analysis, and the multi-level analysis, the correlation between different time points was taken into account. Patterns over time of the three methods were comparable. In general, results from repeated measures ANOVA showed the most favorable energy scores, and results from the multi-level analysis the least favorable. Due to the separate subgroups per time point in the cross-sectional analysis, and the relatively small number of patients in the repeated measures ANOVA, inclusion of predictors was only possible in the multi-level analysis. Conclusion Results obtained with the various methods of analysis differed, indicating some reduction of bias took place. Multi-level analysis is a useful approach to study changes over time in a data set where missing data, to reduce bias, make efficient use of available data, and to include predictors, in studies concerning the effects of LgTX on HRQL.

  5. Finite-key security analysis for multilevel quantum key distribution

    Science.gov (United States)

    Brádler, Kamil; Mirhosseini, Mohammad; Fickler, Robert; Broadbent, Anne; Boyd, Robert

    2016-07-01

    We present a detailed security analysis of a d-dimensional quantum key distribution protocol based on two and three mutually unbiased bases (MUBs) both in an asymptotic and finite-key-length scenario. The finite secret key rates (in bits per detected photon) are calculated as a function of the length of the sifted key by (i) generalizing the uncertainly relation-based insight from BB84 to any d-level 2-MUB QKD protocol and (ii) by adopting recent advances in the second-order asymptotics for finite block length quantum coding (for both d-level 2- and 3-MUB QKD protocols). Since the finite and asymptotic secret key rates increase with d and the number of MUBs (together with the tolerable threshold) such QKD schemes could in principle offer an important advantage over BB84. We discuss the possibility of an experimental realization of the 3-MUB QKD protocol with the orbital angular momentum degrees of freedom of photons.

  6. Large-scale parametric survival analysis.

    Science.gov (United States)

    Mittal, Sushil; Madigan, David; Cheng, Jerry Q; Burd, Randall S

    2013-10-15

    Survival analysis has been a topic of active statistical research in the past few decades with applications spread across several areas. Traditional applications usually consider data with only a small numbers of predictors with a few hundreds or thousands of observations. Recent advances in data acquisition techniques and computation power have led to considerable interest in analyzing very-high-dimensional data where the number of predictor variables and the number of observations range between 10(4) and 10(6). In this paper, we present a tool for performing large-scale regularized parametric survival analysis using a variant of the cyclic coordinate descent method. Through our experiments on two real data sets, we show that application of regularized models to high-dimensional data avoids overfitting and can provide improved predictive performance and calibration over corresponding low-dimensional models.

  7. The multilevel analysis of surface acting and mental health: A moderation of positive group affective tone

    Science.gov (United States)

    Lee, Meng-Shiu; Huang, Jui-Chan; Wu, Tzu-Jung

    2017-06-01

    The purpose of this study is to investigate the relationship among surface acting, mental health, and positive group affective tone. According to the prior theory, this study attempts to establish a comprehensive research framework among these variables, and furthermore tests the moderating effect of positive group affective tone. Data were collected from 435 employees in 52 service industrial companies by questionnaire, and this study conducted multilevel analysis. The results showed that surface acting will negatively affect the mental health. In addition, the positive group affective tone have significant moderating effect on the relationship among surface acting and mental health. Finally, this study discusses managerial implications and highlights future research suggestions.

  8. Characterization of deep aquifer dynamics using principle component analysis of sequential multilevel data

    Directory of Open Access Journals (Sweden)

    D. Kurtzman

    2011-10-01

    Full Text Available Two sequential multilevel profiles were obtained in an observation well opened to a 130 m thick, unconfined, contaminated aquifer, in Tel Aviv, Israel. While the general profile characteristics of major ions, trace elements, and Volatile Organic Compounds (VOC were maintained in the two sampling campaigns conducted 295 days apart, the vertical locations of high concentration gradients were shifted between the two profiles. Principle Component Analysis (PCA of the chemical variables resulted in a first Principal Component (PC which was responsible for ∼60% of the variability, and was highly correlated with depth. PCA revealed three distinct depth-dependent water bodies in both multilevel profiles, which were found to be shifted vertically between the sampling events. This shift cut across a clayey bed which separated between the top and intermediate water bodies in the first profile, and was located entirely within the intermediate water body in the second profile. Continuous Electrical Conductivity (EC monitoring in a packed off section of the observation well revealed an event in which a distinct water body flowed through the monitored section (v ∼ 150 m yr−1. Compilation of the aforementioned data and analysis lead to a conclusion that the observed changes in the profiles resulted from dominantly lateral flow of water bodies in the aquifer rather than vertical flow. The significance of this study is twofold: (a it demonstrates the utility of sequential multilevel observations from deep wells and the efficacy of PCA for evaluating this data. (b The fact that distinct water bodies of 10–100 m vertical and horizontal dimensions flow under contaminated sites has implications for monitoring and remediation.

  9. Overweight and obesity in India: policy issues from an exploratory multi-level analysis.

    Science.gov (United States)

    Siddiqui, Md Zakaria; Donato, Ronald

    2016-06-01

    This article analyses a nationally representative household dataset-the National Family Health Survey (NFHS-3) conducted in 2005 to 2006-to examine factors influencing the prevalence of overweight/obesity in India. The dataset was disaggregated into four sub-population groups-urban and rural females and males-and multi-level logit regression models were used to estimate the impact of particular covariates on the likelihood of overweight/obesity. The multi-level modelling approach aimed to identify individual and macro-level contextual factors influencing this health outcome. In contrast to most studies on low-income developing countries, the findings reveal that education for females beyond a particular level of educational attainment exhibits a negative relationship with the likelihood of overweight/obesity. This relationship was not observed for males. Muslim females and all Sikh sub-populations have a higher likelihood of overweight/obesity suggesting the importance of socio-cultural influences. The results also show that the relationship between wealth and the probability of overweight/obesity is stronger for males than females highlighting the differential impact of increasing socio-economic status on gender. Multi-level analysis reveals that states exerted an independent influence on the likelihood of overweight/obesity beyond individual-level covariates, reflecting the importance of spatially related contextual factors on overweight/obesity. While this study does not disentangle macro-level 'obesogenic' environmental factors from socio-cultural network influences, the results highlight the need to refrain from adopting a 'one size fits all' policy approach in addressing the overweight/obesity epidemic facing India. Instead, policy implementation requires a more nuanced and targeted approach to incorporate the growing recognition of socio-cultural and spatial contextual factors impacting on healthy behaviours.

  10. Building systems technical condition assessment based on the multilevel probabilistic analysis (rus

    Directory of Open Access Journals (Sweden)

    Sokolov V.A.

    2011-11-01

    Full Text Available Methods based on the stochastic apparatus technical diagnostics are put forward to solve problems concerning determination of the structural elements technical condition. Diagnosis is performed using probabilistic methods of recognition of technical conditions of complex technical systems. The diagnosis is conducted with the help of probabilistic methods of the complex engineering systems condition recognition based on the Bayesian analysis. The aforementioned approach and information theory methods are applied to run the multilevel diagnostics of elements and systems of floor slabs in old urban buildings. Multilevel diagnostics was done in the concepts of information entropy. During the analysis of the results of forward and reverse traces on the hierarchical diagnostics structure the next conclusion was made. The forward trace allows to determine the technical condition and category for the each element of each level in the hierarchical structure and the reverse trace gives a possibility to evaluate the contribution of each element condition to the information about the whole building condition. The last point can be an argumentative basis for the account of physical depreciation of building structures.

  11. [Multilevel Analysis in Health Services Research in Healthcare Organizations: Benefits, Requirements and Implementation].

    Science.gov (United States)

    Ansmann, L; Kuhr, K; Kowalski, C

    2017-03-01

    Multilevel Analysis (MLA) are still rarely used in Health Services Research in Germany, though hierarchical data, e. g. from patients clustered in hospitals, is often present. MLA provide the valuable opportunity to study the health care context in health care organizations and the associations between context and health care outcomes. This article's aims are to introduce this particular method of data analysis, to discuss its' benefits and its' applicability particularly for Health Services Research focusing on organizational characteristics and to provide a concise guideline for performing the analysis. First, the benefits and the necessity for MLA compared to ordinary correlation analyses in the case of hierarchical data are discussed. Furthermore, the statistical requirements and key decisions for the performance of MLA are illustrated. © Georg Thieme Verlag KG Stuttgart · New York.

  12. Variation in plasma calcium analysis in primary care in Sweden - a multilevel analysis

    Directory of Open Access Journals (Sweden)

    Eggertsen Robert

    2010-05-01

    Full Text Available Abstract Background Primary hyperparathyroidism (pHPT is a common disease that often remains undetected and causes severe disturbance especially in postmenopausal women. Therefore, national recommendations promoting early pHPT detection by plasma calcium (P-Ca have been issued in Sweden. In this study we aimed to investigate variation of P-Ca analysis between physicians and health care centres (HCCs in primary care in county of Skaraborg, Sweden. Methods In this cross sectional study of patients' records during 2005 we analysed records from 154 629 patients attending 457 physicians at 24 HCCs. We used multilevel logistic regression analysis (MLRA and adjusted for patient, physician and HCC characteristics. Differences were expressed as median odds ratio (MOR. Results There was a substantial variation in number of P-Ca analyses between both HCCs (MORHCC 1.65 [1.44-2.07] and physicians (MORphysician 1.95 [1.85-2.08]. The odds for a P-Ca analysis were lower for male patients (OR 0.80 [0.77-0.83] and increased with the number of diagnoses (OR 25.8 [23.5-28.5]. Sex of the physician had no influence on P-Ca test ordering (OR 0.93 [0.78-1.09]. Physicians under education ordered most P-Ca analyses (OR 1.69 [1.35-2.24] and locum least (OR 0.73 [0.57-0.94]. More of the variance was attributed to the physician level than the HCC level. Different mix of patients did not explain this variance between physicians. Theoretically, if a patient were able to change both GP and HCC, the odds of a P-Ca analysis would in median increase by 2.45. Including characteristics of the patients, physicians and HCCs in the MLRA model did not explain the variance. Conclusions The physician level was more important than the HCC level for the variation in P-Ca analysis, but further exploration of unidentified contextual factors is crucial for future monitoring of practice variation.

  13. Social capital and the utilization of maternal and child health services in India: a multilevel analysis.

    Science.gov (United States)

    Story, William T

    2014-07-01

    This study examines the association between social capital and the utilization of antenatal care, professional delivery care, and childhood immunizations using a multilevel analytic sample of 10,739 women who recently gave birth and 7403 children between one and five years of age in 2293 communities and 22 state-groups from the 2005 India Human Development Survey. Exploratory factor analysis was used to create and validate six social capital measures that were used in multilevel logistic regression models to examine whether each form of social capital had an independent, contextual effect on health care use. Results revealed that social capital operated at the community level in association with all three care-seeking behaviors; however, the results differed based on the type of health care utilized. Specifically, components of social capital that led to heterogeneous bridging ties were positively associated with all three types of health care use, whereas components of social capital that led to strong bonding ties were negatively associated with the use of preventive care, but positively associated with professional delivery care.

  14. Bone dimensional variations at implants placed in fresh extraction sockets: a multilevel multivariate analysis.

    Science.gov (United States)

    Tomasi, Cristiano; Sanz, Mariano; Cecchinato, Denis; Pjetursson, Bjarni; Ferrus, Jorge; Lang, Niklaus P; Lindhe, Jan

    2010-01-01

    To use multilevel, multivariate models to analyze factors that may affect bone alterations during healing after an implant immediately placed into an extraction socket. Data included in the current analysis were obtained from a clinical trial in which a series of measurements were performed to characterize the extraction site immediately after implant installation and at re-entry 4 months later. A regression multilevel, multivariate model was built to analyze factors affecting the following variables: (i) the distance between the implant surface and the outer bony crest (S-OC), (ii) the horizontal residual gap (S-IC), (iii) the vertical residual gap (R-D) and (iv) the vertical position of the bone crest opposite the implant (R-C). It was demonstrated that (i) the S-OC change was significantly affected by the thickness of the bone crest; (ii) the size of the residual gap was dependent of the size of the initial gap and the thickness of the bone crest; and (iii) the reduction of the buccal vertical gap was dependent on the age of the subject. Moreover, the position of the implant opposite the alveolar crest of the buccal ridge and its bucco-lingual implant position influenced the amount of buccal crest resorption. Clinicians must consider the thickness of the buccal bony wall in the extraction site and the vertical as well as the horizontal positioning of the implant in the socket, because these factors will influence hard tissue changes during healing.

  15. The role of supervisor emotional support on individual job satisfaction: A multilevel analysis.

    Science.gov (United States)

    Pohl, Sabine; Galletta, Maura

    2017-02-01

    Supervisor emotional support is a strong determinant of job satisfaction. There is no study examining the effect of supervisor emotional support at the group level on job satisfaction. Multilevel statistical techniques can help disentangle the effects of subjective assessments from those of group factors. The study's aim was to examine the moderating role of supervisor emotional support (group-level variable) on the relationship between work engagement and job satisfaction (individual-level variables). A cross-sectional study was performed in 39units from three Belgian hospitals. A total of 323 nurses completed a self-reported questionnaire. We carried out a multilevel analysis by using Hierarchical Linear Modeling. The results showed that the cross-level interaction was significant. Hence, at individual-level, the nurses with high levels of work engagement showed high levels of job satisfaction and this relationship was stronger when supervisor emotional support at group-level was high. Contextual differences among groups had an impact on the form of the work engagement-job satisfaction relationship. This relationship between work engagement and job satisfaction is an individual and group level phenomenon. Ways to enhance emotional supervisor support include training supervisors in providing support and enhancing communication between nurses and supervisors. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. In situ multi-level analysis of viscoelastic deformation mechanisms in tendon collagen.

    Science.gov (United States)

    Gupta, H S; Seto, J; Krauss, S; Boesecke, P; Screen, H R C

    2010-02-01

    Tendon is a hydrated multi-level fibre composite, in which time-dependent behaviour is well established. Studies indicate significant stress relaxation, considered important for optimising tissue stiffness. However, whilst this behaviour is well documented, the mechanisms associated with the response are largely unknown. This study investigates the sub-structural mechanisms occurring during stress relaxation at both the macro (fibre) and nano (fibril) levels of the tendon hierarchy. Stress relaxation followed a two-stage exponential behaviour, during which structural changes were visible at the fibre and fibril levels. Fibril relaxation and fibre sliding showed a double exponential response, while fibre sliding was clearly the largest contributor to relaxation. The amount of stress relaxation and sub-structural reorganisation increased with increasing load increments, but fibre sliding was consistently the largest contributor to stress relaxation. A simple model of tendon viscoelasticity at the fibril and fibre levels has been developed, capturing this behaviour by serially coupling a Voigt element (collagen fibril), with two Maxwell elements (non-collagenous matrix between fibrils and fibres). This multi-level analysis provides a first step towards understanding how sub-structural interactions contribute to viscoelastic behaviour. It indicates that nano- and micro-scale shearing are significant dissipative mechanisms, and the kinetics of relaxation follows a two-stage exponential decay, well fitted by serially coupled viscoelastic elements.

  17. Regression Analysis of Restricted Mean Survival Time Based on Pseudo-Observations

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Hansen, Mette Gerster; Klein, John P.

    2004-01-01

    censoring; hazard function; health economics; mean survival time; pseudo-observations; regression model; restricted mean survival time; survival analysis......censoring; hazard function; health economics; mean survival time; pseudo-observations; regression model; restricted mean survival time; survival analysis...

  18. Regression analysis of restricted mean survival time based on pseudo-observations

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Hansen, Mette Gerster; Klein, John P.

    censoring; hazard function; health economics; regression model; survival analysis; mean survival time; restricted mean survival time; pseudo-observations......censoring; hazard function; health economics; regression model; survival analysis; mean survival time; restricted mean survival time; pseudo-observations...

  19. The application of multilevel modelling to account for the influence of walking speed in gait analysis.

    Science.gov (United States)

    Keene, David J; Moe-Nilssen, Rolf; Lamb, Sarah E

    2016-01-01

    Differences in gait performance can be explained by variations in walking speed, which is a major analytical problem. Some investigators have standardised speed during testing, but this can result in an unnatural control of gait characteristics. Other investigators have developed test procedures where participants walking at their self-selected slow, preferred and fast speeds, with computation of gait characteristics at a standardised speed. However, this analysis is dependent upon an overlap in the ranges of gait speed observed within and between participants, and this is difficult to achieve under self-selected conditions. In this report a statistical analysis procedure is introduced that utilises multilevel modelling to analyse data from walking tests at self-selected speeds, without requiring an overlap in the range of speeds observed or the routine use of data transformations.

  20. Lean production tools and decision latitude enable conditions for innovative learning in organizations: a multilevel analysis.

    Science.gov (United States)

    Fagerlind Ståhl, Anna-Carin; Gustavsson, Maria; Karlsson, Nadine; Johansson, Gun; Ekberg, Kerstin

    2015-03-01

    The effect of lean production on conditions for learning is debated. This study aimed to investigate how tools inspired by lean production (standardization, resource reduction, visual monitoring, housekeeping, value flow analysis) were associated with an innovative learning climate and with collective dispersion of ideas in organizations, and whether decision latitude contributed to these associations. A questionnaire was sent out to employees in public, private, production and service organizations (n = 4442). Multilevel linear regression analyses were used. Use of lean tools and decision latitude were positively associated with an innovative learning climate and collective dispersion of ideas. A low degree of decision latitude was a modifier in the association to collective dispersion of ideas. Lean tools can enable shared understanding and collective spreading of ideas, needed for the development of work processes, especially when decision latitude is low. Value flow analysis played a pivotal role in the associations.

  1. Analysis of Functional Data with Focus on Multinomial Regression and Multilevel Data

    DEFF Research Database (Denmark)

    Mousavi, Seyed Nourollah

    Functional data analysis (FDA) is a fast growing area in statistical research with increasingly diverse range of application from economics, medicine, agriculture, chemometrics, etc. Functional regression is an area of FDA which has received the most attention both in aspects of application...... and methodological development. Our main Functional data analysis (FDA) is a fast growing area in statistical research with increasingly diverse range of application from economics, medicine, agriculture, chemometrics, etc. Functional regression is an area of FDA which has received the most attention both in aspects...... and the prediction of the response at time t only depends on th concurrently observed predictor. We introduce a version of this model for multilevel functional data of the type subjectunit, with the unit-level data being functional observations. Finally, in the fourth paper we show how registration can be applied...

  2. Multilevel analysis of individual differences in regularities of grapheme-color associations in synesthesia.

    Science.gov (United States)

    Hamada, Daisuke; Yamamoto, Hiroki; Saiki, Jun

    2017-08-01

    Grapheme-color synesthesia is a neurological phenomenon where visual perception of letters and numbers stimulates perception of a specific color. Grapheme-color correspondences have been shown to be systematically associated with grapheme properties, including visual shape difference, ordinality, and frequency. However, the contributions of grapheme factors differ across individuals. In this study, we applied multilevel analysis to test whether individual differences in regularities of grapheme-color associations could be explained by individual styles of processing grapheme properties. These processing styles are reflected by the type of synesthetic experience. Specifically, we hypothesized that processing focusing on shape differences would be associated with projector synesthetes, while processing focusing on ordinality or familiarity would be associated with associator synesthetes. The analysis revealed that ordinality and familiarity factors were expressed more strongly among associators than among projectors. This finding suggests that grapheme-color associations are partly determined by the type of synesthetic experience. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Multi-level post-processing for Korean character recognition using morphological analysis and linguistic evaluation

    CERN Document Server

    Lee, G; Yoo, J H; Lee, Geunbae; Lee, Jong-Hyeok; Yoo, JinHee

    1996-01-01

    Most of the post-processing methods for character recognition rely on contextual information of character and word-fragment levels. However, due to linguistic characteristics of Korean, such low-level information alone is not sufficient for high-quality character-recognition applications, and we need much higher-level contextual information to improve the recognition results. This paper presents a domain independent post-processing technique that utilizes multi-level morphological, syntactic, and semantic information as well as character-level information. The proposed post-processing system performs three-level processing: candidate character-set selection, candidate eojeol (Korean word) generation through morphological analysis, and final single eojeol-sequence selection by linguistic evaluation. All the required linguistic information and probabilities are automatically acquired from a statistical corpus analysis. Experimental results demonstrate the effectiveness of our method, yielding error correction r...

  4. Female political representation and child health: Evidence from a multilevel analysis.

    Science.gov (United States)

    Quamruzzaman, Amm; Lange, Matthew

    2016-10-24

    This article explores the impact of female political representation in national parliaments on child health through a multilevel analysis. Using available Demographic and Health Surveys, we employ both cross-sectional data for 51 low- and middle-income countries and longitudinal data for 20 countries with multiple surveys. For both the cross-sectional and longitudinal analyses, female representation is negatively related to infant mortality and positively related to measles vaccination status. To explore potential mechanisms, we control for state spending on health and analyze whether the impact of female representation depends on a critical mass of female representatives. The analysis offers evidence that state spending accounts for some of the mediation effect and that the impact of female representation on infant death depends on a critical mass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Quality of Research Design Moderates Effects of Grade Retention on Achievement: A Meta-Analytic, Multilevel Analysis

    Science.gov (United States)

    Allen, Chiharu S.; Chen, Qi; Willson, Victor L.; Hughes, Jan N.

    2009-01-01

    The present meta-analysis examines the effect of grade retention on academic outcomes and investigates systemic sources of variability in effect sizes. Using multilevel modeling (MLM), the authors investigate characteristics of 207 effect sizes across 22 studies published between 1990 and 2007 at two levels: the study (between) and individual…

  6. Multilevel Analysis of the Impact of School-Level Tobacco Policies on Adolescent Smoking: The Case of Michigan

    Science.gov (United States)

    Paek, Hye-Jin; Hove, Thomas; Oh, Hyun Jung

    2013-01-01

    Background: In efforts to curb and prevent youth smoking, school tobacco policies have become an important and effective strategy. This study explores the degrees and types of tobacco-free school policy (TFSP) enforcement that are associated with adolescent smoking. Methods: A multilevel analysis was performed using 983 students who are nested in…

  7. Multi-Level Discourse Analysis in a Physics Teaching Methods Course from the Psychological Perspective of Activity Theory

    Science.gov (United States)

    Vieira, Rodrigo Drumond; Kelly, Gregory J.

    2014-01-01

    In this paper, we present and apply a multi-level method for discourse analysis in science classrooms. This method is based on the structure of human activity (activity, actions, and operations) and it was applied to study a pre-service physics teacher methods course. We argue that such an approach, based on a cultural psychological perspective,…

  8. Savings in Public Services after the Crisis: A Multilevel Analysis of Public Preferences in the EU27 (Working Paper 8)

    NARCIS (Netherlands)

    S.G.J. Van de Walle (Steven); S.R. Jilke (Sebastian)

    2012-01-01

    textabstractPolicy responses to the financial crisis can be divided into cyclical and anti-cyclical approaches. The former advocates reducing public spending in times of financial constraints. The latter approach advocates public spending to boost the economy. Using multinomial multilevel analysis o

  9. Multi-Level Discourse Analysis in a Physics Teaching Methods Course from the Psychological Perspective of Activity Theory

    Science.gov (United States)

    Vieira, Rodrigo Drumond; Kelly, Gregory J.

    2014-01-01

    In this paper, we present and apply a multi-level method for discourse analysis in science classrooms. This method is based on the structure of human activity (activity, actions, and operations) and it was applied to study a pre-service physics teacher methods course. We argue that such an approach, based on a cultural psychological perspective,…

  10. Employees' Willingness to Participate in Work-Related Learning: A Multilevel Analysis of Employees' Learning Intentions

    Science.gov (United States)

    Kyndt, Eva; Onghena, Patrick; Smet, Kelly; Dochy, Filip

    2014-01-01

    The current study focuses on employees' learning intentions, or the willingness to undertake formal work-related learning. This cross-sectional survey study included a sample of 1,243 employees that are nested within 21 organisations. The results of the multilevel analysis show that self-directedness in career processes, time management,…

  11. Employees' Willingness to Participate in Work-Related Learning: A Multilevel Analysis of Employees' Learning Intentions

    Science.gov (United States)

    Kyndt, Eva; Onghena, Patrick; Smet, Kelly; Dochy, Filip

    2014-01-01

    The current study focuses on employees' learning intentions, or the willingness to undertake formal work-related learning. This cross-sectional survey study included a sample of 1,243 employees that are nested within 21 organisations. The results of the multilevel analysis show that self-directedness in career processes, time management,…

  12. A mixture model for the joint analysis of latent developmental trajectories and survival

    NARCIS (Netherlands)

    Klein Entink, R.H.; Fox, J.P.; Hout, A. van den

    2011-01-01

    A general joint modeling framework is proposed that includes a parametric stratified survival component for continuous time survival data, and a mixture multilevel item response component to model latent developmental trajectories given mixed discrete response data. The joint model is illustrated in

  13. A mixture model for the joint analysis of latent developmental trajectories and survival

    NARCIS (Netherlands)

    Klein Entink, R.H.; Fox, J.P.; Hout, A. van den

    2011-01-01

    A general joint modeling framework is proposed that includes a parametric stratified survival component for continuous time survival data, and a mixture multilevel item response component to model latent developmental trajectories given mixed discrete response data. The joint model is illustrated in

  14. Multi-level segment analysis: definition and application in turbulent systems

    Science.gov (United States)

    Wang, L. P.; Huang, Y. X.

    2015-06-01

    For many complex systems the interaction of different scales is among the most interesting and challenging features. It seems not very successful to extract the physical properties in different scale regimes by the existing approaches, such as the structure-function and Fourier spectrum method. Fundamentally, these methods have their respective limitations, for instance scale mixing, i.e. the so-called infrared and ultraviolet effects. To make improvements in this regard, a new method, multi-level segment analysis (MSA) based on the local extrema statistics, has been developed. Benchmark (fractional Brownian motion) verifications and the important case tests (Lagrangian and two-dimensional turbulence) show that MSA can successfully reveal different scaling regimes which have remained quite controversial in turbulence research. In general the MSA method proposed here can be applied to different dynamic systems in which the concepts of multiscale and multifractality are relevant.

  15. The familial influence of loss and trauma on refugee mental health: a multilevel path analysis.

    Science.gov (United States)

    Nickerson, Angela; Bryant, Richard A; Brooks, Robert; Steel, Zachary; Silove, Derrick; Chen, Jack

    2011-02-01

    Although the impact of human rights violations on the mental health of refugees has been well documented, little is known about these effects at a family level. In this study the authors examined the relationships among loss, trauma, and mental health at the individual and family levels in resettled Mandaean refugees (N = 315). Trauma, loss, posttraumatic stress disorder, depression, complicated grief, and mental health-related quality of life were assessed. A multilevel path analysis revealed that loss and trauma significantly impacted on psychological outcomes at both the individual and family levels. Effect sizes ranged from .21 to .68 at the individual level, and .38 to .99 at the family level, highlighting the importance of the family when considering the psychological impact of refugee-related trauma. Copyright © 2011 International Society for Traumatic Stress Studies.

  16. Efficient analysis of dielectric radomes using multilevel fast multipole algorithm with CRWG basis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A full-wave analysis of the electromagnetic problem of a three-dimensional (3-D) antenna radiating through a 3-D dielectric radome is preserued.The problem is formulated using the Poggio-Miller-Chang-Harrington-Wu(PMCHW) approach for homogeneous dielectric objects and the electric field integral equation for conducting objects.The integral equations are discretized by the method of moment (MoM),in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions.The resultant matrix equation is then solved by the multilevel fast multipole algorithm (MLFMA) and fast far-field approximation (FAFFA) is used to further accelerate the computation.The radiation patterns of dipole arrays in the presence of radomes are presented.The numerical results demonstrate the accuracy and versatility of this method.

  17. Social Network Community Detection for DMA Creation: Criteria Analysis through Multilevel Optimization

    Directory of Open Access Journals (Sweden)

    Bruno M. Brentan

    2017-01-01

    Full Text Available Management of large water distribution systems can be improved by dividing their networks into so-called district metered areas (DMAs. However, such divisions must be based on appropriated technical criteria. Considering the importance of deeply understanding the relationship between DMA creation and these criteria, this work proposes a performance analysis of DMA generation that takes into account such indicators as resilience index, demand similarity, pressure uniformity, water age (and thus water quality, solution implantation costs, and electrical consumption. To cope with the complexity of the problem, suitable mathematical techniques are proposed in this paper. We use a social community detection technique to define the sectors, and then a multilevel particle swarm optimization approach is applied to find the optimal placement and operating point of the necessary devices. The results obtained by implementing the methodology in a real water supply network show its validity and the meaningful influence on the final result of, especially, elevation and pipe length.

  18. Religion, religiosity, and the attitudes toward homosexuality--a multilevel analysis of 79 countries.

    Science.gov (United States)

    Jäckle, Sebastian; Wenzelburger, Georg

    2015-01-01

    Although attitudes toward homosexuality have become more liberal, particularly in industrialized Western countries, there is still a great deal of variance in terms of worldwide levels of homonegativity. Using data from the two most recent waves of the World Values Survey (1999-2004, 2005-2009), this article seeks to explain this variance by means of a multilevel analysis of 79 countries. We include characteristics on the individual level, as age or gender, as well as aggregate variables linked to specificities of the nation-states. In particular, we focus on the religious denomination of a person and her religiosity to explain her attitude toward homosexuality. We find clear differences in levels of homonegativity among the followers of the individual religions.

  19. Multi-level segment analysis: definition and application in turbulent systems

    CERN Document Server

    Wang, L P

    2015-01-01

    For many complex systems the interaction of different scales is among the most interesting and challenging features. It seems not very successful to extract the physical properties in different scale regimes by the existing approaches, such as structure-function and Fourier spectrum method. Fundamentally these methods have their respective limitations, for instance scale mixing, i.e. the so-called infrared and ultraviolet effects. To make improvement in this regard, a new method, multi-level segment analysis (MSA) based on the local extrema statistics, has been developed. Benchmark (fractional Brownian motion) verifications and the important case tests (Lagrangian and two-dimensional turbulence) show that MSA can successfully reveal different scaling regimes, which has been remaining quite controversial in turbulence research. In general the MSA method proposed here can be applied to different dynamic systems in which the concepts of multiscaling and multifractal are relevant.

  20. Adolescents' utilisation of psychiatric care, neighbourhoods and neighbourhood socioeconomic deprivation: a multilevel analysis.

    Directory of Open Access Journals (Sweden)

    Anna-Karin Ivert

    Full Text Available Mental health problems among adolescents have become a major public health issue, and it is therefore important to increase knowledge on the contextual determinants of adolescent mental health. One such determinant is the socioeconomic structure of the neighbourhood. The present study has two central objectives, (i to examine if neighbourhood socioeconomic deprivation is associated to individual variations in utilisation of psychiatric care in a Swedish context, and (ii to investigate if neighbourhood boundaries are a valid construct for identifying contexts that influence individual variations in psychiatric care utilization. Data were obtained from the Longitudinal Multilevel Analysis in Scania (LOMAS database. The study population consists of all boys and girls aged 13-18 years (N=18,417, who were living in the city of Malmö, Sweden, in 2005. Multilevel logistic regression analysis was applied to estimate the probability of psychiatric care utilisation. The results from the study indicate that the neighbourhood of residence had little influence on psychiatric care utilisation. Although we initially found a variation between neighbourhoods, this general contextual effect was very small (i.e. 1.6%. The initial conclusive association between the neighbourhood level of disadvantage and psychiatric care utilisation (specific contextual effect disappeared following adjustment for individual and family level variables. Our results suggest the neighbourhoods in Malmö (at least measured in terms of SAMS-areas, do not provide accurate information for discriminating adolescents utilisation of psychiatric care. The SAMS-areas appears to be an inappropriate construct of the social environment that influences adolescent utilisation of psychiatric care. Therefore, public health interventions should be directed to the whole city rather than to specific neighbourhoods. However, since geographical, social or cultural contexts may be important for our

  1. Multi-level bootstrap analysis of stable clusters in resting-state fMRI.

    Science.gov (United States)

    Bellec, Pierre; Rosa-Neto, Pedro; Lyttelton, Oliver C; Benali, Habib; Evans, Alan C

    2010-07-01

    A variety of methods have been developed to identify brain networks with spontaneous, coherent activity in resting-state functional magnetic resonance imaging (fMRI). We propose here a generic statistical framework to quantify the stability of such resting-state networks (RSNs), which was implemented with k-means clustering. The core of the method consists in bootstrapping the available datasets to replicate the clustering process a large number of times and quantify the stable features across all replications. This bootstrap analysis of stable clusters (BASC) has several benefits: (1) it can be implemented in a multi-level fashion to investigate stable RSNs at the level of individual subjects and at the level of a group; (2) it provides a principled measure of RSN stability; and (3) the maximization of the stability measure can be used as a natural criterion to select the number of RSNs. A simulation study validated the good performance of the multi-level BASC on purely synthetic data. Stable networks were also derived from a real resting-state study for 43 subjects. At the group level, seven RSNs were identified which exhibited a good agreement with the previous findings from the literature. The comparison between the individual and group-level stability maps demonstrated the capacity of BASC to establish successful correspondences between these two levels of analysis and at the same time retain some interesting subject-specific characteristics, e.g. the specific involvement of subcortical regions in the visual and fronto-parietal networks for some subjects.

  2. Using Visual Analysis to Evaluate and Refine Multilevel Models of Single-Case Studies

    Science.gov (United States)

    Baek, Eun Kyeng; Petit-Bois, Merlande; Van den Noortgate, Wim; Beretvas, S. Natasha; Ferron, John M.

    2016-01-01

    In special education, multilevel models of single-case research have been used as a method of estimating treatment effects over time and across individuals. Although multilevel models can accurately summarize the effect, it is known that if the model is misspecified, inferences about the effects can be biased. Concern with the potential for model…

  3. Multi-level tree analysis of pulmonary artery/vein trees in non-contrast CT images

    Science.gov (United States)

    Gao, Zhiyun; Grout, Randall W.; Hoffman, Eric A.; Saha, Punam K.

    2012-02-01

    Diseases like pulmonary embolism and pulmonary hypertension are associated with vascular dystrophy. Identifying such pulmonary artery/vein (A/V) tree dystrophy in terms of quantitative measures via CT imaging significantly facilitates early detection of disease or a treatment monitoring process. A tree structure, consisting of nodes and connected arcs, linked to the volumetric representation allows multi-level geometric and volumetric analysis of A/V trees. Here, a new theory and method is presented to generate multi-level A/V tree representation of volumetric data and to compute quantitative measures of A/V tree geometry and topology at various tree hierarchies. The new method is primarily designed on arc skeleton computation followed by a tree construction based topologic and geometric analysis of the skeleton. The method starts with a volumetric A/V representation as input and generates its topologic and multi-level volumetric tree representations long with different multi-level morphometric measures. A new recursive merging and pruning algorithms are introduced to detect bad junctions and noisy branches often associated with digital geometric and topologic analysis. Also, a new notion of shortest axial path is introduced to improve the skeletal arc joining two junctions. The accuracy of the multi-level tree analysis algorithm has been evaluated using computer generated phantoms and pulmonary CT images of a pig vessel cast phantom while the reproducibility of method is evaluated using multi-user A/V separation of in vivo contrast-enhanced CT images of a pig lung at different respiratory volumes.

  4. Comparative Analysis and Simulation of Diode Clamped & Cascaded H-Bridge Multilevel Inverter using SPWM Technique

    Directory of Open Access Journals (Sweden)

    Mohit Jain

    2015-01-01

    Full Text Available Multilevel inverters have become more popular over the years in high power medium voltage applications without the use of a transformer and with promise of less disturbance & reduced harmonic distortion. In this paper, two types of multilevel converter in three phase configuration, cascaded H-Bridge multilevel inverter (CMLI and diode clamped multilevel inverter (DCMLI of 5 and 7-level are modelled and compared in the case of feeding of a three phase squirrel cage induction motor. Here, carrier based sinusoidal pulse width modulation (SPWM technique is used as the modulation strategy. These modulation strategy include phase disposition technique (PD, phase opposition disposition technique (POD, and an alternative phase opposition disposition technique (APOD. A detailed study of the modulation technique has been carried out through MATLAB/SIMULINK for both multilevel converters and a comparative evaluation between DCMLI and CMLI using SPWM technique in terms of THD%.

  5. Area-level poverty and preterm birth risk: A population-based multilevel analysis

    Directory of Open Access Journals (Sweden)

    Muglia Louis A

    2008-09-01

    Full Text Available Abstract Background Preterm birth is a complex disease with etiologic influences from a variety of social, environmental, hormonal, genetic, and other factors. The purpose of this study was to utilize a large population-based birth registry to estimate the independent effect of county-level poverty on preterm birth risk. To accomplish this, we used a multilevel logistic regression approach to account for multiple co-existent individual-level variables and county-level poverty rate. Methods Population-based study utilizing Missouri's birth certificate database (1989–1997. We conducted a multilevel logistic regression analysis to estimate the effect of county-level poverty on PTB risk. Of 634,994 births nested within 115 counties in Missouri, two levels were considered. Individual-level variables included demographics factors, prenatal care, health-related behavioral risk factors, and medical risk factors. The area-level variable included the percentage of the population within each county living below the poverty line (US census data, 1990. Counties were divided into quartiles of poverty; the first quartile (lowest rate of poverty was the reference group. Results PTB th quartile (4.9%, p adjOR 1.18 (95% CI 1.03, 1.35, with a similar effect at earlier gestational ages (adjOR 1.27 (95% CI 1.06, 1.52. Conclusion Women residing in socioeconomically deprived areas are at increased risk of preterm birth, above other underlying risk factors. Although the risk increase is modest, it affects a large number of pregnancies.

  6. Determinants of venous thromboembolism among hospitalizations of US adults: a multilevel analysis.

    Directory of Open Access Journals (Sweden)

    James Tsai

    Full Text Available Venous thromboembolism (VTE is a significant clinical and public health concern. We evaluated a variety of multilevel factors--demographics, clinical and insurance status, preexisting comorbid conditions, and hospital characteristics--for VTE diagnosis among hospitalizations of US adults.We generated adjusted odds ratios with 95% confidence intervals (CIs and determined sources of outcome variation by conducting multilevel logistic regression analysis of data from the 2011 Nationwide Inpatient Sample that included 6,710,066 hospitalizations of US adults nested within 1,039 hospitals.Among hospitalizations of adults, age, sex, race or ethnicity, total days of hospital stay, status of health insurance, and operating room procedure were important determinants of VTE diagnosis; each of the following preexisting comorbid conditions--acquired immune deficiency syndrome, anemia, arthritis, congestive heart failure, coagulopathy, hypertension, lymphoma, metastatic cancer, other neurological disorders, obesity, paralysis, pulmonary circulation disorders, renal failure, solid tumor without metastasis, and weight loss--was associated independently with 1.04 (95% CI: 1.02-1.06 to 2.91 (95% CI: 2.81-3.00 times increased likelihood of VTE diagnosis than among hospitalizations of adults without any of these corresponding conditions. The presence of 2 or more of such conditions was associated a 180%-450% increased likelihood of a VTE diagnosis. Hospitalizations of adults who were treated in urban hospitals were associated with a 14%-15% increased likelihood of having a VTE diagnosis than those treated in rural hospitals. Approximately 7.4% of the total variation in VTE diagnosis occurred between hospitals.The presence of certain comorbidities and hospital contextual factors is associated with significantly elevated likelihood of VTE diagnosis among hospitalizations of adults. The findings of this study underscore the importance of clinical risk assessment and

  7. Invited commentary: multilevel analysis of individual heterogeneity-a fundamental critique of the current probabilistic risk factor epidemiology.

    Science.gov (United States)

    Merlo, Juan

    2014-07-15

    In this issue of the Journal, Dundas et al. (Am J Epidemiol. 2014;180(2):197-207) apply a hitherto infrequent multilevel analytical approach: multiple membership multiple classification (MMMC) models. Specifically, by adopting a life-course approach, they use a multilevel regression with individuals cross-classified in different contexts (i.e., families, early schools, and neighborhoods) to investigate self-reported health and mental health in adulthood. They provide observational evidence suggesting the relevance of the early family environment for launching public health interventions in childhood in order to improve health in adulthood. In their analyses, the authors distinguish between specific contextual measures (i.e., the association between particular contextual characteristics and individual health) and general contextual measures (i.e., the share of the total interindividual heterogeneity in health that appears at each level). By doing so, they implicitly question the traditional probabilistic risk factor epidemiology including classical "neighborhood effects" studies. In fact, those studies use simple hierarchical structures and disregard the analysis of general contextual measures. The innovative MMMC approach properly responds to the call for a multilevel eco-epidemiology against a widespread probabilistic risk factors epidemiology. The risk factors epidemiology is not only reduced to individual-level analyses, but it also embraces many current "multilevel analyses" that are exclusively focused on analyzing contextual risk factors.

  8. Time varying effects in survival analysis

    DEFF Research Database (Denmark)

    Scheike, Thomas H.

    2002-01-01

    additive risk model; counting process; proportional hazards model; semi-parametric models; survival data; time-varying effects; nonparametric testing......additive risk model; counting process; proportional hazards model; semi-parametric models; survival data; time-varying effects; nonparametric testing...

  9. Multilevel models applications using SAS

    CERN Document Server

    Wang, Jichuan; Fisher, James F

    2011-01-01

    This book covers a broad range of topics about multilevel modeling. The goal is to help readers to understand the basic concepts, theoretical frameworks, and application methods of multilevel modeling. It is at a level also accessible to non-mathematicians, focusing on the methods and applications of various multilevel models and using the widely used statistical software SAS®. Examples are drawn from analysis of real-world research data.

  10. Multilevel Models Applications Using SAS

    CERN Document Server

    Wang, Jichuan; Fisher, James

    2011-01-01

    This book covers a broad range of topics about multilevel modeling. The goal is to help readersto understand the basic concepts, theoretical frameworks, and application methods of multilevel modeling. Itis at a level also accessible to non-mathematicians, focusing on the methods and applications of various multilevel models and using the widely used statistical software SAS®.Examples are drawn from analysis of real-world research data.

  11. Religious attendance in cross-national perspective : a multilevel analysis of 60 countries

    NARCIS (Netherlands)

    Ruiter, S.; Tubergen, F.A. van

    2009-01-01

    Why are some nations more religious than others? This article proposes a multilevel framework in which country differences in religious attendance are explained by contextual, individual, and crosslevel interaction effects. Hypotheses from different theories are simultaneously tested with data from

  12. The influence of regional deprivation index on personal happiness using multilevel analysis.

    Science.gov (United States)

    Kim, Kil Hun; Chun, Jin-Ho; Sohn, Hae Sook

    2015-01-01

    The objective of the present study was to identify the factors that influence the happiness index of community residents, by considering personal and regional aspects, and to use as evidence of efforts for improvement of the happiness index. The study was conducted based on information from 16,270 participants who met the data requirement among those who participated in the 2011 South Gyeongsang Community Health Survey. Of the factors that can influence the happiness index, socioeconomic characteristics, health behavior, morbidity, and healthcare use, social contact, and participation in social activities were classified as personal factors; for regional factors, data from the 2010 census were used to extrapolate the regional deprivation indices at the submunicipal-level (eup, myeon, and dong) in South Gyeongsang Province. The happiness index for each characteristic was compared to that for others via t-test and ANOVA, and multilevel analysis was performed, using four models: a basic model for identification of only random effects, model 1 for identification of personal factors, model 2 for identification of regional factors, and model 3 for simultaneous consideration of both personal and regional factors. The mean happiness index was 63.2 points (64.6 points in males and 62.0 points in females), while the mean deprivation index was -1.58 points. In the multilevel analysis, the regional-level variance ratio of the basic model was 10.8%, confirming interregional differences. At the personal level, higher happiness indices were seen in groups consisting of males with high educational level, high income, high degree of physical activity, sufficient sleep, active social contact, and participation in social activities; whereas lower happiness indices were seen in people who frequently skipped breakfast, had unmet healthcare needs, and had accompanying diseases, as well as those with higher deprivation index. The study confirmed that the happiness index of community

  13. Area-Level and Individual-Level Factors for Teenage Motherhood: A Multilevel Analysis in Japan

    Science.gov (United States)

    Baba, Sachiko; Iso, Hiroyasu; Fujiwara, Takeo

    2016-01-01

    Background Teenage motherhood is strongly associated with a range of disadvantages for both the mother and the child. No epidemiological studies have examined related factors for teenage motherhood at both area and individual levels among Japanese women. Therefore, we performed a multilevel analysis of nationwide data in Japan to explore the association of area- and individual-level factors with teenage motherhood. Methods The study population comprised 21,177 mothers living in 47 prefectures who had their first, singleton baby between 10 and 17 January or between 10 and 17 July, 2001. Information on the prefecture in which the mothers resided was linked to prefecture-level variables. Primary outcomes were area-level characteristics (single-mother households, three-generation households, college enrollment, abortions, juvenile crime, and per capita income) and individual-level characteristics, and divided into tertiles or quintiles based on their variable distributions. Multilevel logistic regression analysis was then performed. Results There were 440 teenage mothers (2.1%) in this study. In addition to individual low level of education [adjusted odds ratio (OR), 7.40; 95% confidence interval (CI), 5.59–9.78], low income [4.23 (2.95–6.08)], and smoking [1.65 (1.31–2.07)], high proportions of single-mother households [1.72 (1.05–2.80)] and three-generation household [1.81 (1.17–2.78)], and per capita income [2.19 (1.06–3.81)] at an area level were positively associated, and high level of college enrollment [0.46 (0.25–0.83)] and lower crime rate [0.62 (0.40–0.98)] at area level were inversely associated with teenage motherhood compared with the corresponding women living in prefectures with the lowest levels of these variables. Conclusions Our findings suggest that encouraging the completion of higher education and reducing the number of single-mother household at an area level may be important public health strategies to reduce teenage motherhood

  14. Graphics and statistics for cardiology: survival analysis.

    Science.gov (United States)

    May, Susanne; McKnight, Barbara

    2017-03-01

    Reports of data in the medical literature frequently lack information needed to assess the validity and generalisability of study results. Some recommendations and standards for reporting have been developed over the last two decades, but few are available specifically for survival data. We provide recommendations for tabular and graphical representations of survival data. We argue that data and analytic software should be made available to promote reproducible research.

  15. A general framework for parametric survival analysis.

    Science.gov (United States)

    Crowther, Michael J; Lambert, Paul C

    2014-12-30

    Parametric survival models are being increasingly used as an alternative to the Cox model in biomedical research. Through direct modelling of the baseline hazard function, we can gain greater understanding of the risk profile of patients over time, obtaining absolute measures of risk. Commonly used parametric survival models, such as the Weibull, make restrictive assumptions of the baseline hazard function, such as monotonicity, which is often violated in clinical datasets. In this article, we extend the general framework of parametric survival models proposed by Crowther and Lambert (Journal of Statistical Software 53:12, 2013), to incorporate relative survival, and robust and cluster robust standard errors. We describe the general framework through three applications to clinical datasets, in particular, illustrating the use of restricted cubic splines, modelled on the log hazard scale, to provide a highly flexible survival modelling framework. Through the use of restricted cubic splines, we can derive the cumulative hazard function analytically beyond the boundary knots, resulting in a combined analytic/numerical approach, which substantially improves the estimation process compared with only using numerical integration. User-friendly Stata software is provided, which significantly extends parametric survival models available in standard software. Copyright © 2014 John Wiley & Sons, Ltd.

  16. Refined multi-level methodology in parallel computing environment for BWR RIA analysis

    Science.gov (United States)

    Solis-Rodarte, Jorge

    2000-12-01

    Best-estimate methodologies in boiling water reactor can reduce the traditional conservative thermal margins imposed on the designs and during the operation of this type of nuclear reactors. Traditional operating thermal margins are obtained based on simplified modeling techniques that are supplemented with the required dose of conservatism. For instance, much more realistic transient pin peaking distributions can be predicted by applying a dehomogenization algorithm, based on a flux reconstruction scheme which uses nodal results during both steady state and transient calculation at each time step. A subchannel analysis module for obtaining thermal margins supplements the calculation approach used. A multi-level methodology to extend the TRAC-BF1/NEM coupled code capability to obtain the transient fuel rod response has been implemented. To fulfill the development requirements some improved neutronic models were implemented into the NEM solution algorithm, namely the pin power reconstruction capability, and the simulation of a dynamic scram. The obtained results were coupled to a subchannel analysis module: COBRA-TF T-H subchannel analysis code. The objective of the pin power reconstruction capability of NEM is to locate the most limiting node (axial region of assembly/channel) within the core. The power information obtained from the NEM 3D neutronic calculation is used by the hot channel analysis module (COBRA-TF). COBRA-TF needs also the T-H conditions at the boundary nodes. This information is provided by TRACBF1 T-H system analysis code. The Subchannel analysis module uses this information to re-calculate the fluid, thermal and hydraulics conditions in the most limiting node (axial region of assembly/channel) within the core.

  17. Multilevel Models for the Analysis of Angle-Specific Torque Curves with Application to Master Athletes

    Directory of Open Access Journals (Sweden)

    Carvalho Humberto M.

    2015-12-01

    Full Text Available The aim of this paper was to outline a multilevel modeling approach to fit individual angle-specific torque curves describing concentric knee extension and flexion isokinetic muscular actions in Master athletes. The potential of the analytical approach to examine between individual differences across the angle-specific torque curves was illustrated including between-individuals variation due to gender differences at a higher level. Torques in concentric muscular actions of knee extension and knee extension at 60°·s-1 were considered within a range of motion between 5°and 85° (only torques “truly” isokinetic. Multilevel time series models with autoregressive covariance structures with standard multilevel models were superior fits compared with standard multilevel models for repeated measures to fit anglespecific torque curves. Third and fourth order polynomial models were the best fits to describe angle-specific torque curves of isokinetic knee flexion and extension concentric actions, respectively. The fixed exponents allow interpretations for initial acceleration, the angle at peak torque and the decrement of torque after peak torque. Also, the multilevel models were flexible to illustrate the influence of gender differences on the shape of torque throughout the range of motion and in the shape of the curves. The presented multilevel regression models may afford a general framework to examine angle-specific moment curves by isokinetic dynamometry, and add to the understanding mechanisms of strength development, particularly the force-length relationship, both related to performance and injury prevention.

  18. Multilevel Models for the Analysis of Angle-Specific Torque Curves with Application to Master Athletes.

    Science.gov (United States)

    Carvalho, Humberto M

    2015-12-22

    The aim of this paper was to outline a multilevel modeling approach to fit individual angle-specific torque curves describing concentric knee extension and flexion isokinetic muscular actions in Master athletes. The potential of the analytical approach to examine between individual differences across the angle-specific torque curves was illustrated including between-individuals variation due to gender differences at a higher level. Torques in concentric muscular actions of knee extension and knee extension at 60º·s(-1) were considered within a range of motion between 5º and 85º (only torques "truly" isokinetic). Multilevel time series models with autoregressive covariance structures with standard multilevel models were superior fits compared with standard multilevel models for repeated measures to fit angle-specific torque curves. Third and fourth order polynomial models were the best fits to describe angle-specific torque curves of isokinetic knee flexion and extension concentric actions, respectively. The fixed exponents allow interpretations for initial acceleration, the angle at peak torque and the decrement of torque after peak torque. Also, the multilevel models were flexible to illustrate the influence of gender differences on the shape of torque throughout the range of motion and in the shape of the curves. The presented multilevel regression models may afford a general framework to examine angle-specific moment curves by isokinetic dynamometry, and add to the understanding mechanisms of strength development, particularly the force-length relationship, both related to performance and injury prevention.

  19. Musculoskeletal diseases of spine and risk factors during Dentistry: Multilevel ergonomic analysis

    Directory of Open Access Journals (Sweden)

    Charilaos Koutis

    2011-07-01

    Full Text Available The prevalence of occupational musculoskeletal diseases (MSDs among dentists is estimated to be high, despite the ergonomic interventions in this sector. The aim of the present study was a the evaluation of spine MSDs in dentists and b the assessment of risk factors related to dentist practice. Material and Method: The sample of the present study consisted of 16 dentists (n=16. The participants divided into two (2 groups, based on MSDs of the spine. A multilevel ergonomic analysis was conducted in both groups, which evaluated individual, physical and occupational risk factors during nine (9 dental procedures. For the analysis of data were used, direct methods (video, observation, amended postural analysis OWAS, indirect method (questionnaire and quantitative methods of ergonomic analysis (computerized mediball postural stabilizer cushion. Results: The most frequent MSDs of spine among dentists in the present research are localized on low back (66,7% and neck (8,3%. Based on OWAS analysis of 2348 working postures, statistically significant correlation was found between dentists' MSDs and factors concerning both dentists (weakness of stabilizer muscles of spine, awkward positions during working time, fatigue (p< 0,05 as well as the nature of dental work (specific dental procedures, patient's, the position of patients, tools and dentists during the working time, certain areas of the mouth, working hours, lack of breaks, etc (p< 0,05 respectively. Conclusions: Low back pain and neck pain are the most frequent MSDs of dentists' spine. They are related to individual and other occupational factors which could have been prevented using proper ergonomic interventions.

  20. A brief conceptual tutorial on multilevel analysis in social epidemiology: investigating contextual phenomena in different groups of people

    OpenAIRE

    Merlo, J; Yang, M.; Chaix, B.; Lynch, J; Rastam, L.

    2005-01-01

    Study objective: (1) To provide a didactic and conceptual (rather than mathematical) link between multilevel regression analysis (MLRA) and social epidemiological concepts. (2) To develop an epidemiological vision of MLRA focused on measures of health variation and clustering of individual health status within areas, which is useful to operationalise the notion of "contextual phenomenon". The paper shows how to investigate (1) whether there is clustering within neighbourhoods, (2) to which ex...

  1. Fast food purchasing and access to fast food restaurants: a multilevel analysis of VicLANES.

    Science.gov (United States)

    Thornton, Lukar E; Bentley, Rebecca J; Kavanagh, Anne M

    2009-05-27

    While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. In this paper we attempt to address these methodological problems using data from the Victorian Lifestyle and Neighbourhood Environments Study (VicLANES) - a cross-sectional multilevel study conducted within metropolitan Melbourne, Australia in 2003. The VicLANES data used in this analysis included 2547 participants from 49 census collector districts in metropolitan Melbourne, Australia. The outcome of interest was the total frequency of fast food purchased for consumption at home within the previous month (never, monthly and weekly) from five major fast food chains (Red Rooster, McDonalds, Kentucky Fried Chicken, Hungry Jacks and Pizza Hut). Three measures of fast food access were created: density and variety, defined as the number of fast food restaurants and the number of different fast food chains within 3 kilometres of road network distance respectively, and proximity defined as the road network distance to the closest fast food restaurant.Multilevel multinomial models were used to estimate the associations between fast food restaurant access and purchasing with never purchased as the reference category. Models were adjusted for confounders including determinants of demand (attitudes and tastes that influence food purchasing decisions) as well as individual and area socio-economic characteristics. Purchasing fast food on a monthly basis was related to the variety of fast food restaurants (odds ratio 1.13; 95% confidence interval 1.02 - 1.25) after adjusting for individual and area characteristics. Density and proximity were not found to be significant predictors of fast food purchasing after adjustment for individual socio-economic predictors. Although we found an independent

  2. Fast food purchasing and access to fast food restaurants: a multilevel analysis of VicLANES

    Directory of Open Access Journals (Sweden)

    Kavanagh Anne M

    2009-05-01

    Full Text Available Abstract Background While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. In this paper we attempt to address these methodological problems using data from the Victorian Lifestyle and Neighbourhood Environments Study (VicLANES – a cross-sectional multilevel study conducted within metropolitan Melbourne, Australia in 2003. Methods The VicLANES data used in this analysis included 2547 participants from 49 census collector districts in metropolitan Melbourne, Australia. The outcome of interest was the total frequency of fast food purchased for consumption at home within the previous month (never, monthly and weekly from five major fast food chains (Red Rooster, McDonalds, Kentucky Fried Chicken, Hungry Jacks and Pizza Hut. Three measures of fast food access were created: density and variety, defined as the number of fast food restaurants and the number of different fast food chains within 3 kilometres of road network distance respectively, and proximity defined as the road network distance to the closest fast food restaurant. Multilevel multinomial models were used to estimate the associations between fast food restaurant access and purchasing with never purchased as the reference category. Models were adjusted for confounders including determinants of demand (attitudes and tastes that influence food purchasing decisions as well as individual and area socio-economic characteristics. Results Purchasing fast food on a monthly basis was related to the variety of fast food restaurants (odds ratio 1.13; 95% confidence interval 1.02 – 1.25 after adjusting for individual and area characteristics. Density and proximity were not found to be significant predictors of fast food purchasing after adjustment for individual socio

  3. Multilevel corporate environmental responsibility.

    Science.gov (United States)

    Karassin, Orr; Bar-Haim, Aviad

    2016-12-01

    The multilevel empirical study of the antecedents of corporate social responsibility (CSR) has been identified as "the first knowledge gap" in CSR research. Based on an extensive literature review, the present study outlines a conceptual multilevel model of CSR, then designs and empirically validates an operational multilevel model of the principal driving factors affecting corporate environmental responsibility (CER), as a measure of CSR. Both conceptual and operational models incorporate three levels of analysis: institutional, organizational, and individual. The multilevel nature of the design allows for the assessment of the relative importance of the levels and of their components in the achievement of CER. Unweighted least squares (ULS) regression analysis reveals that the institutional-level variables have medium relationships with CER, some variables having a negative effect. The organizational level is revealed as having strong and positive significant relationships with CER, with organizational culture and managers' attitudes and behaviors as significant driving forces. The study demonstrates the importance of multilevel analysis in improving the understanding of CSR drivers, relative to single level models, even if the significance of specific drivers and levels may vary by context.

  4. Analysis of survival data from telemetry projects

    Science.gov (United States)

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

    1985-01-01

    Telemetry techniques can be used to study the survival rates of animal populations and are particularly suitable for species or settings for which band recovery models are not. Statistical methods for estimating survival rates and parameters of survival distributions from observations of radio-tagged animals will be described. These methods have been applied to medical and engineering studies and to the study of nest success. Estimates and tests based on discrete models, originally introduced by Mayfield, and on continuous models, both parametric and nonparametric, will be described. Generalizations, including staggered entry of subjects into the study and identification of mortality factors will be considered. Additional discussion topics will include sample size considerations, relocation frequency for subjects, and use of covariates.

  5. [Variability in preventive activities among primary care teams in Catalonia. Application of a multilevel analysis].

    Science.gov (United States)

    Fusté, J; Rué, M

    2001-01-01

    To determine whether variability exists among primary care teams (PCTs) in Catalonia in opportunistic screening activities (screening for smoking, drinking, hypertension and tetanus vaccination) and to analyze the explanatory factors in the individual characteristics of the population treated and the characteristics of the PCT. A multilevel analysis with individual and PCT explanatory variables was performed. The data were draw from a sample of 3,000 clinical histories from the adult population treated in 1995 in 30 PCTs from the restructured primary care network in Catalonia and from PCT characteristics. The recording of preventive activities in the clinical histories increased with the number of risk factors and/or diseases diagnosed, the number of other preventive activities recorded, and age. Recording of arterial pressure was more frequent in women while the remaining preventive activities were more frequent in men. Workload impeded opportunistic detection. Greater recording of antitetanus vaccination was associated with the number of years that the PCT had been functioning and with wider geographical area. Recording of smoking was higher in urban areas. Variability in opportunistic detection exists among PCTs in Catalonia. The characteristics of the PCT and the population treated that explain part of this variability are identified. Lower workload favors preventive activities in primary care.

  6. A multilevel path analysis of social networks and social interaction in the neighbourhood

    Directory of Open Access Journals (Sweden)

    Pauline van den Berg

    2015-05-01

    Full Text Available The topic of neighbourhood-based social interactions has gained attention in the last decades in the light of urban policies that aim to deal with problems regarding social segregation and exclusion, quality of life and liveability in urban areas. Social interactions are expected to play an important role in dealing with these problems. However, empirical studies investigating to which extent neighbourhood characteristics can improve social contacts among residents are scarce and inconclusive. Therefore, this paper studies the role of socio-demographics and neighbourhood characteristics in the formation of social network ties and social interactions with neighbours. Based on data collected in 2011 in 70 different neighbourhoods of Eindhoven in the Netherlands in a survey among 751 respondents these relationships are analysed using a multi-level path analysis approach. The results indicate that neighbourhood-based contacts are influenced by personal and household characteristics, such as education, income, work status, ethnicity, household composition, and years at the current address. Neighbourhood characteristics are not found to affect social network size, the share of neighbours in the network or the frequency of interaction with neighbours.

  7. A multilevel path analysis of contact frequency between social network members

    Science.gov (United States)

    van den Berg, Pauline; Arentze, Theo; Timmermans, Harry

    2012-04-01

    Recently, there has been an increasing interest in the role of social networks in spatial-choice and travel behavior. It has been acknowledged that social activities and the travel for these activities can emerge from individuals' social networks and that social activities are responsible for an important portion of travel demand. The influence of information and communication technologies (ICT's) is also important in this respect. The purpose of the paper is to examine the effects of characteristics of egos and ego-alter relationships on the frequency of social interaction by different communication modes, using multilevel path analysis. The analyses are based on social network data collected in 2008 in the Eindhoven region in the Netherlands among 116 respondents. The results indicate a complementary relationship between contact frequencies by different modes. The contact frequencies of the different modes, especially face-to-face and telephone, can also be largely explained by the ego's personal characteristics and the type of relationship and the distance between ego and alter.

  8. Athletes' perceptions of role ambiguity and coaching competency in sport teams: a multilevel analysis.

    Science.gov (United States)

    Bosselut, Grégoire; Heuzé, Jean-Philippe; Eys, Mark A; Fontayne, Paul; Sarrazin, Philippe

    2012-06-01

    The purpose of this study was to examine the relationship between athletes' perceptions of role ambiguity and two theoretically derived dimensions of coaching competency (i.e., game strategy and technique competencies). A total of 243 players from 26 teams representing various interdependent sports completed French versions of the Role Ambiguity Scale and the Coaching Competency Scale. Multilevel analyses supported the existence of relationships between the four dimensions of role ambiguity and the two dimensions of coaching competency at both individual and team levels. When the levels were considered jointly, athletes perceiving greater ambiguity in their role in both offensive and defensive contexts were more critical of their coach's capacities to lead their team during competitions and to diagnose or formulate instructions during training sessions. The results also indicated that the dimension of scope of responsibilities was the main contributor to the relationship with coaching competency at an individual level, whereas role evaluation was the main contributor to this relationship at a group level. Findings are discussed in relation to the role episode model, the role ambiguity dimensions involved in the relationships according to the level of analysis considered, and the salience of ambiguity perceptions in the offensive context.

  9. Mapping the global journey of anthropogenic aluminum: a trade-linked multilevel material flow analysis.

    Science.gov (United States)

    Liu, Gang; Müller, Daniel B

    2013-10-15

    Material cycles have become increasingly coupled and interconnected in a globalizing era. While material flow analysis (MFA) has been widely used to characterize stocks and flows along technological life cycle within a specific geographical area, trade networks among individual cycles have remained largely unexplored. Here we developed a trade-linked multilevel MFA model to map the contemporary global journey of anthropogenic aluminum. We demonstrate that the anthropogenic aluminum cycle depends substantially on international trade of aluminum in all forms and becomes highly interconnected in nature. While the Southern hemisphere is the main primary resource supplier, aluminum production and consumption concentrate in the Northern hemisphere, where we also find the largest potential for recycling. The more developed countries tend to have a substantial and increasing presence throughout the stages after bauxite refining and possess highly consumption-based cycles, thus maintaining advantages both economically and environmentally. A small group of countries plays a key role in the global redistribution of aluminum and in the connectivity of the network, which may render some countries vulnerable to supply disruption. The model provides potential insights to inform government and industry policies in resource criticality, supply chain security, value chain management, and cross-boundary environmental impacts mitigation.

  10. Childhood vitamin A capsule supplementation coverage in Nigeria: a multilevel analysis of geographic and socioeconomic inequities.

    Science.gov (United States)

    Aremu, Olatunde; Lawoko, Stephen; Dalal, Koustuv

    2010-10-01

    Vitamin A deficiency (VAD) is a huge public health burden among preschool-aged children in sub-Saharan Africa, and is associated with a high level of susceptibility to infectious diseases and pediatric blindness. We examined the Nigerian national vitamin A capsule (VAC) supplementation program, a short-term cost-effective intervention for prevention of VAD-associated morbidity for equity in terms of socioeconomic and geographic coverage. Using the most current, nationally representative data from the 2008 Nigerian Demographic and Health Survey, we applied multilevel regression analysis on 19,555 children nested within 888 communities across the six regions of Nigeria. The results indicate that there was variability in uptake of VAC supplement among the children, which could be attributed to several characteristics at individual, household, and community levels. Individual-level characteristics, such as maternal occupation, were shown to be associated with receipt of VAC supplement. The results also reveal that household wealth status is the only household-level characteristic that is significantly associated with receipt of VAC, while neighborhood socioeconomic disadvantage and geographic location were the community-level characteristics that determined receipt of VAC. The findings from this study have shown that both individual and contextual socioeconomic status, together with geographic location, is important for uptake of VAC. These findings underscore the need to accord the VAC supplementation program the much needed priority with focus on characteristics of neighborhoods (communities), in addition to individual-level characteristics.

  11. MK4MDD: a multi-level knowledge base and analysis platform for major depressive disorder.

    Directory of Open Access Journals (Sweden)

    Liyuan Guo

    Full Text Available BACKGROUND: Major depressive disorder (MDD is a complex neuropsychiatric syndrome with high heterogeneity. There are different levels of biological components that underlie MDD and interact with each other. To uncover the disease mechanism, large numbers of studies at different levels have been conducted. There is a growing need to integrate data from multiple levels of research into a database to provide a systematic review of current research results. The cross level integration will also help bridge gaps of different research levels for further understanding on MDD. So far, there has been no such effort for MDD. DESCRIPTIONS: We offer researchers a Multi-level Knowledge base for MDD (MK4MDD to study the interesting interplay of components in the pathophysiological cascade of MDD from genetic variations to diagnostic syndrome. MK4MDD contains 2,341 components and 5,206 relationships between components based on reported experimental results obtained by diligent literature reading with manual curation. All components were well classified with careful curation and supplementary annotation. The powerful search and visualization tools make all data in MK4MDD form a cross-linked network to be applied to a broad range of both basic and applied research. CONCLUSIONS: MK4MDD aims to provide researchers with a central knowledge base and analysis platform for MDD etiological and pathophysiological mechanisms research. MK4MDD is freely available at http://mdd.psych.ac.cn.

  12. Childhood Vitamin A Capsule Supplementation Coverage in Nigeria: A Multilevel Analysis of Geographic and Socioeconomic Inequities

    Directory of Open Access Journals (Sweden)

    Olatunde Aremu

    2010-01-01

    Full Text Available Vitamin A deficiency (VAD is a huge public health burden among preschool-aged children in sub-Saharan Africa, and is associated with a high level of susceptibility to infectious diseases and pediatric blindness. We examined the Nigerian national vitamin A capsule (VAC supplementation program, a short-term cost-effective intervention for prevention of VAD-associated morbidity for equity in terms of socioeconomic and geographic coverage. Using the most current, nationally representative data from the 2008 Nigerian Demographic and Health Survey, we applied multilevel regression analysis on 19,555 children nested within 888 communities across the six regions of Nigeria. The results indicate that there was variability in uptake of VAC supplement among the children, which could be attributed to several characteristics at individual, household, and community levels. Individual-level characteristics, such as maternal occupation, were shown to be associated with receipt of VAC supplement. The results also reveal that household wealth status is the only household-level characteristic that is significantly associated with receipt of VAC, while neighborhood socioeconomic disadvantage and geographic location were the community-level characteristics that determined receipt of VAC. The findings from this study have shown that both individual and contextual socioeconomic status, together with geographic location, is important for uptake of VAC. These findings underscore the need to accord the VAC supplementation program the much needed priority with focus on characteristics of neighborhoods (communities, in addition to individual-level characteristics.

  13. Targeting, universalism, and single-mother poverty: a multilevel analysis across 18 affluent democracies.

    Science.gov (United States)

    Brady, David; Burroway, Rebekah

    2012-05-01

    We examine the influence of individual characteristics and targeted and universal social policy on single-mother poverty with a multilevel analysis across 18 affluent Western democracies. Although single mothers are disproportionately poor in all countries, there is even more cross-national variation in single-mother poverty than in poverty among the overall population. By far, the United States has the highest rate of poverty among single mothers among affluent democracies. The analyses show that single-mother poverty is a function of the household's employment, education, and age composition, and the presence of other adults in the household. Beyond individual characteristics, social policy exerts substantial influence on single-mother poverty. We find that two measures of universal social policy significantly reduce single-mother poverty. However, one measure of targeted social policy does not have significant effects, and another measure is significantly negative only when controlling for universal social policy. Moreover, the effects of universal social policy are larger. Additional analyses show that universal social policy does not have counterproductive consequences in terms of family structure or employment, while the results are less clear for targeted social policy. Although debates often focus on altering the behavior or characteristics of single mothers, welfare universalism could be an even more effective anti-poverty strategy.

  14. 一种新的安全Petri网及其多级安全机制分析%A Novel Multilevel Security Petri Net and its Security Analysis

    Institute of Scientific and Technical Information of China (English)

    王小明; 赵宗涛; 袁崇义

    2003-01-01

    Petri Net(PN) is a very important modeling methodology for dynamic concurrent system. Many PN modelsare available in existing literature,but a little attention has been paid to such a PN that supports multilevel securepolicies. In this paper,a novel PN model ,named as multilevel secure PN (MLSPN),is proposed ,and its multilevel se-curity mechanism is analysed formally. MLSPN has of a flexible and strong power to support a dynamic time con-traint,and the security covert channel can also be eleminated. Therefore MLSPN may have practical application inmany areas ,such as secure workflow development ,secure database design,and secure protocol analysis ,etc.

  15. Economic and Sociological Correlates of Suicides: Multilevel Analysis of the Time Series Data in the United Kingdom.

    Science.gov (United States)

    Sun, Bruce Qiang; Zhang, Jie

    2016-03-01

    For the effects of social integration on suicides, there have been different and even contradictive conclusions. In this study, the selected economic and social risks of suicide for different age groups and genders in the United Kingdom were identified and the effects were estimated by the multilevel time series analyses. To our knowledge, there exist no previous studies that estimated a dynamic model of suicides on the time series data together with multilevel analysis and autoregressive distributed lags. The investigation indicated that unemployment rate, inflation rate, and divorce rate are all significantly and positively related to the national suicide rates in the United Kingdom from 1981 to 2011. Furthermore, the suicide rates of almost all groups above 40 years are significantly associated with the risk factors of unemployment and inflation rate, in comparison with the younger groups.

  16. Multilevel Control System of Regional Power Consumption: Analysis of Infrastructure Elements Interconnections, Efficiency Evaluation

    Directory of Open Access Journals (Sweden)

    Marina Nikolaevna Myznikova

    2016-10-01

    Full Text Available Fundamental strategic programs in the spheres of power and economics adopted at various levels of management, are not always capable to solve the problem of power efficiency. The changes of systemic connections of economy and power elements are one of the basic problems of management at the regional level. The development of market relations has caused the growth of uncertainty factors at all levels of power consumption management. An insufficient estimation of system infrastructural interrelations and an individualization of organizational-economic relations of economic subjects and their localization, have generated the intersystem conflictness in distribution of power resources and have aggravated the problem of estimating power consumption efficiency at a systemic level. The restriction of application of the traditional management methods based on the principles of technological efficiency of the processes of energy manufacture and consumption, is connected with the information ruptures caused by the growth of factors of uncertainty and inconsistency of efficiency criteria. Application of modern methods of power consumption forecasting has a number of essential restrictions. At the present stage the management of power consumption in multilevel systems is aimed at realisation of system integrity and economic coordination of manufacture elements, transfer and consumption at regional level and demands working out of the new effective management methods based on the analysis of system interrelations. Allocation of system interrelations depends on features of development of electropower sector, active and passive elements of the structure of consumption, power balance. The analysis and estimation of interrelations of power and economic sphere allow to improve methodology of management of power consumption at the regional level in the conditions of uncertainty.

  17. A Bayesian-based multilevel factorial analysis method for analyzing parameter uncertainty of hydrological model

    Science.gov (United States)

    Liu, Y. R.; Li, Y. P.; Huang, G. H.; Zhang, J. L.; Fan, Y. R.

    2017-10-01

    In this study, a Bayesian-based multilevel factorial analysis (BMFA) method is developed to assess parameter uncertainties and their effects on hydrological model responses. In BMFA, Differential Evolution Adaptive Metropolis (DREAM) algorithm is employed to approximate the posterior distributions of model parameters with Bayesian inference; factorial analysis (FA) technique is used for measuring the specific variations of hydrological responses in terms of posterior distributions to investigate the individual and interactive effects of parameters on model outputs. BMFA is then applied to a case study of the Jinghe River watershed in the Loess Plateau of China to display its validity and applicability. The uncertainties of four sensitive parameters, including soil conservation service runoff curve number to moisture condition II (CN2), soil hydraulic conductivity (SOL_K), plant available water capacity (SOL_AWC), and soil depth (SOL_Z), are investigated. Results reveal that (i) CN2 has positive effect on peak flow, implying that the concentrated rainfall during rainy season can cause infiltration-excess surface flow, which is an considerable contributor to peak flow in this watershed; (ii) SOL_K has positive effect on average flow, implying that the widely distributed cambisols can lead to medium percolation capacity; (iii) the interaction between SOL_AWC and SOL_Z has noticeable effect on the peak flow and their effects are dependent upon each other, which discloses that soil depth can significant influence the processes of plant uptake of soil water in this watershed. Based on the above findings, the significant parameters and the relationship among uncertain parameters can be specified, such that hydrological model's capability for simulating/predicting water resources of the Jinghe River watershed can be improved.

  18. Health at the borders: Bayesian multilevel analysis of women's malnutrition determinants in Ethiopia

    Directory of Open Access Journals (Sweden)

    Tefera Darge Delbiso

    2016-07-01

    Full Text Available Background: Women's malnutrition, particularly undernutrition, remains an important public health challenge in Ethiopia. Although various studies examined the levels and determinants of women's nutritional status, the influence of living close to an international border on women's nutrition has not been investigated. Yet, Ethiopian borders are regularly affected by conflict and refugee flows, which might ultimately impact health. Objective: To investigate the impact of living close to borders in the nutritional status of women in Ethiopia, while considering other important covariates. Design: Our analysis was based on the body mass index (BMI of 6,334 adult women aged 20–49 years, obtained from the 2011 Ethiopian Demographic and Health Survey (EDHS. A Bayesian multilevel multinomial logistic regression analysis was used to capture the clustered structure of the data and the possible correlation that may exist within and between clusters. Results: After controlling for potential confounders, women living close to borders (i.e. ≤100 km in Ethiopia were 59% more likely to be underweight (posterior odds ratio [OR]=1.59; 95% credible interval [CrI]: 1.32–1.90 than their counterparts living far from the borders. This result was robust to different choices of border delineation (i.e. ≤50, ≤75, ≤125, and ≤150 km. Women from poor families, those who have no access to improved toilets, reside in lowland areas, and are Muslim, were independently associated with underweight. In contrast, more wealth, higher education, older age, access to improved toilets, being married, and living in urban or lowlands were independently associated with overweight. Conclusions: The problem of undernutrition among women in Ethiopia is most worrisome in the border areas. Targeted interventions to improve nutritional status in these areas, such as improved access to sanitation, economic and livelihood support, are recommended.

  19. Use of traditional medicine and complementary and alternative medicine in Taiwan: a multilevel analysis.

    Science.gov (United States)

    Yeh, Mei-Ling; Lin, Kuan-Chia; Chen, Hsing-Hsia; Wang, Yu-Jen; Huang, Yu-Chiao

    2015-01-01

    As the selection of a medical modality is not completely independent, environmental and sociocultural contexts of ecological validity are desired. This study aimed to apply a multilevel analysis using the Hierarchical Linear Modeling software to examine predictors of traditional medicine (TM)/complementary and alternative medicine (CAM) use in Taiwan on both individual and division levels. Individual-level data were obtained from the government database involving TM/CAM use and its impact on the population, whereas division-level data were obtained from a government annual report. A total of 2310 individuals from 22 administrative divisions of Taiwan were evaluated in the data analysis, of which 86.9% had used at least 1 TM/CAM modality in the past year. The average division of TM/CAM use was 2.86 modalities in the null model and 4.15 in the full model. Significant relationships were found between TM/CAM use and individual-level variables of gender, educational level, monthly income, perceived health status, experience with Western medical treatment, and the cost, effect, and degree of satisfaction with TM/CAM. At the division level, TM/CAM use was significantly related to aging population, employment status, and the number of medical institutions. With a simultaneous evaluation of the individual-level and division-level influences, it was found that the average division of TM/CAM use increased significantly. The place of residence is an important predictor of TM/CAM use. The age factor in predicting TM/CAM use in this study may be overestimated in the population of 26 to 60 years of age, whereas an aging population is important in the average division of TM/CAM use. Efforts to reform health insurance to completely cover the costs of TM/CAM and to better facilitate equality of access of health care in rural and remote areas are deemed necessary.

  20. Assessing the context of health care utilization in Ecuador: A spatial and multilevel analysis

    Directory of Open Access Journals (Sweden)

    Chi Chunhuei

    2010-03-01

    Full Text Available Abstract Background There are few studies that have analyzed the context of health care utilization, particularly in Latin America. This study examines the context of utilization of health services in Ecuador; focusing on the relationship between provision of services and use of both preventive and curative services. Methods This study is cross-sectional and analyzes data from the 2004 National Demographic and Maternal & Child Health dataset. Provider variables come from the Ecuadorian System of Social Indicators (SIISE. Global Moran's I statistic is used to assess spatial autocorrelation of the provider variables. Multilevel modeling is used for the simultaneous analysis of provision of services at the province-level with use of services at the individual level. Results Spatial analysis indicates no significant differences in the density of health care providers among Ecuadorian provinces. After adjusting for various predisposing, enabling, need factors and interaction terms, density of public practice health personnel was positively associated with use of preventive care, particularly among rural households. On the other hand, density of private practice physicians was positively associated with use of curative care, particularly among urban households. Conclusions There are significant public/private, urban/rural gaps in provision of services in Ecuador; which in turn affect people's use of services. It is necessary to strengthen the public health care delivery system (which includes addressing distribution of health workers and national health information systems. These efforts could improve access to health care, and inform the civil society and policymakers on the advances of health care reform.

  1. Control of modular multilevel converters based on time-scale analysis and orthogonal functions

    DEFF Research Database (Denmark)

    Zarri, L.; Tani, A.; Mengoni, M.

    2014-01-01

    Modular multilevel converter (MMC) is a promising multilevel topology for high-voltage applications that has been developed in recent years. The control of MMCs has been analyzed in detail in many papers, showing that the converter capacitors can be kept charged and balanced by controlling...... the circulating current of each leg. The set-point signal of the circulating current is probably the most difficult variable to choose. Typically, it is chosen in such a way to control the total energy and the energy unbalance of each leg. Although several theories are available, the control of the circulating...

  2. Multilevel modeling versus cross-sectional analysis for assessing the longitudinal tracking of cardiovascular risk factors over time.

    Science.gov (United States)

    Xanthakis, Vanessa; Sullivan, Lisa M; Vasan, Ramachandran S

    2013-12-10

    Correlated data are obtained in longitudinal epidemiological studies, where repeated measurements are taken on individuals or groups over time. Such longitudinal data are ideally analyzed using multilevel modeling approaches, which appropriately account for the correlations in repeated responses in the same individual. Commonly used regression models are inappropriate as they assume that measurements are independent. In this tutorial, we use multilevel modeling to demonstrate its use for analysis of correlated data obtained from serial examinations on individuals. We focus on cardiovascular epidemiological research where investigators are often interested in quantifying the relations between clinical risk factors and outcome measures (X and Y, respectively), where X and Y are measured repeatedly over time, for example, using serial observations on participants attending multiple examinations in a longitudinal cohort study. For instance, it may be of interest to evaluate the relations between serial measures of left ventricular mass (outcome) and of its potential determinants (i.e., body mass index and blood pressure), both of which are measured over time. In this tutorial, we describe the application of multilevel modeling to cardiovascular risk factors and outcome data (using serial echocardiographic data as an example of an outcome). We suggest an analytical approach that can be implemented to evaluate relations between any potential outcome of interest and risk factors, including assessment of random effects and nonlinear relations. We illustrate these steps using echocardiographic data from the Framingham Heart Study with SAS PROC MIXED.

  3. Hybrid Surgery Versus Anterior Cervical Discectomy and Fusion in Multilevel Cervical Disc Diseases: A Meta-Analysis.

    Science.gov (United States)

    Zhang, Jianfeng; Meng, Fanxin; Ding, Yan; Li, Jie; Han, Jian; Zhang, Xintao; Dong, Wei

    2016-05-01

    To investigate the outcomes and reliability of hybrid surgery (HS) versus anterior cervical discectomy and fusion (ACDF) for the treatment of multilevel cervical spondylosis and disc diseases.Hybrid surgery, combining cervical disc arthroplasty (CDA) with fusion, is a novel treatment to multilevel cervical degenerated disc disease in recent years. However, the effect and reliability of HS are still unclear compared with ACDF.To investigate the studies of HS versus ACDF in patients with multilevel cervical disease, electronic databases (Medline, Embase, Pubmed, Cochrane library, and Cochrane Central Register of Controlled Trials) were searched. Studies were included when they compared HS with ACDF and reported at least one of the following outcomes: functionality, neck pain, arm pain, cervical range of motion (ROM), quality of life, and incidence of complications. No language restrictions were used. Two authors independently assessed the methodological quality of included studies and extracted the relevant data.Seven clinical controlled trials were included in this study. Two trials were prospective and the other 5 were retrospective. The results of the meta-analysis indicated that HS achieved better recovery of NDI score (P = 0.038) and similar recovery of VAS score (P = 0.058) compared with ACDF at 2 years follow-up. Moreover, the total cervical ROM (C2-C7) after HS was preserved significantly more than the cervical ROM after ACDF (P = 0.000) at 2 years follow-up. Notably, the compensatory increase of the ROM of superior and inferior adjacent segments was significant in ACDF groups at 2-year follow-up (P multilevel cervical spondylosis to preserve cervical ROM and reduce the risk of adjacent disc degeneration. Nonetheless, more well-designed studies with large groups of patients are required to provide further evidence for the benefit and reliability of HS for the treatment of cervical disk diseases.

  4. Multiple imputation of missing blood pressure covariates in survival analysis

    NARCIS (Netherlands)

    Buuren, S. van; Boshuizen, H.C.; Knook, D.L.

    1999-01-01

    This paper studies a non-response problem in survival analysis where the occurrence of missing data in the risk factor is related to mortality. In a study to determine the influence of blood pressure on survival in the very old (85+ years), blood pressure measurements are missing in about 12.5 per c

  5. Survival

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data provide information on the survival of California red-legged frogs in a unique ecosystem to better conserve this threatened species while restoring...

  6. Practical Marginalized Multilevel Models.

    Science.gov (United States)

    Griswold, Michael E; Swihart, Bruce J; Caffo, Brian S; Zeger, Scott L

    2013-01-01

    Clustered data analysis is characterized by the need to describe both systematic variation in a mean model and cluster-dependent random variation in an association model. Marginalized multilevel models embrace the robustness and interpretations of a marginal mean model, while retaining the likelihood inference capabilities and flexible dependence structures of a conditional association model. Although there has been increasing recognition of the attractiveness of marginalized multilevel models, there has been a gap in their practical application arising from a lack of readily available estimation procedures. We extend the marginalized multilevel model to allow for nonlinear functions in both the mean and association aspects. We then formulate marginal models through conditional specifications to facilitate estimation with mixed model computational solutions already in place. We illustrate the MMM and approximate MMM approaches on a cerebrovascular deficiency crossover trial using SAS and an epidemiological study on race and visual impairment using R. Datasets, SAS and R code are included as supplemental materials.

  7. Multilevel analysis of individual and community level factors associated with institutional delivery in Ethiopia.

    Science.gov (United States)

    Mekonnen, Zeleke A; Lerebo, Wondwossen T; Gebrehiwot, Tesfay G; Abadura, Samir A

    2015-08-26

    Improving maternal health is one of the eight millennium development goals to reduce maternal mortality (MM) by three quarters between 1990 and 2015. Institutional delivery is considered to be the most critical intervention in reducing MM and ensuring safe motherhood. However, the level of maternal morbidity and mortality in Ethiopia are among the highest in the world and the proportion of births occurring at health facilities is very low. This study examined the individual and community level factors associated with institutional delivery in Ethiopia. Data from the 2011 Ethiopian demographic and health survey were used to identify individual and community level factors associated with institutional delivery among women who had a live birth during the 5 years preceding the survey. Taking into account the nested structure of the data, multilevel logistic regression analysis has been employed to a nationally representative sample of 7757 women nested with in 595 communities. At the individual level; higher educational level of the women (AOR = 3.60; 95% CI 2.491-5.214), women from richest households (AOR = 1.74; 95% CI 1.143-2.648) and increased ante natal care attendance (AOR = 4.43; 95% CI 3.405-5.751) were associated with institutional delivery. Additionally, at the community level; urban residence (AOR = 4.74; 95% CI 3.196-7.039), residing in communities with high proportion of educated women (AOR = 1.71; 95% CI 1.256-2.319) and residing in communities with high ANC utilization rate (AOR = 1.55; 95% CI 1.132-2.127) had a significant effect on institutional delivery. Also region and distance to health facility showed significant association with institutional delivery. The random effects showed that the variation in institutional delivery service utilization between communities was statistically significant. Both individual and community level factors are associated with institutional delivery service uptake. As a result, further research is needed to better

  8. Socioeconomic inequalities in adolescent depression in South Korea: a multilevel analysis.

    Directory of Open Access Journals (Sweden)

    Hye Yin Park

    Full Text Available BACKGROUND: In recent years, South Korea has witnessed a sustained rise in the prevalence of adolescent depression. In the present study, we sought to investigate family and school environmental influences on adolescent depression. METHODS AND FINDINGS: Middle and high school students (N = 75,066 were randomly selected respondents to a web-based survey and answered questions on their academic and socioeconomic backgrounds, parental support, parental education level, physical activities, lifestyle habits and their experience of depression in the past one year. Two-level multilevel analysis was used to investigate the relationship between depression and individual (level 1 and school (level 2 factors. Girls reported having experienced depression in greater numbers than boys (43.96% vs. 32.03%. A significant association was found between adolescent depression experience and gender, grade, self-rated academic achievement, family affluence scale, parental support, parental education level, lifestyle habits, physical activity and sleep dissatisfaction. The students living with rich parents were more likely to be depressive, and maternal higher education was significantly associated with higher probability of boys' depression experience. Low academic achievement was highly associated with the experience of depression. In school level contexts, girls were found to be less likely to be depressive in girls-only schools. CONCLUSION: The adolescent depression experience is not only an individual phenomenon but is highly associated with other factors such as parents, peers, academic achievement, and even gender mix in the school. Thus, prevention measures on youth depression need to focus on emphasizing less pressure from parents on academic performance, and establishing healthy inter-gender relationships within co-education schools.

  9. Trust increases euthanasia acceptance: a multilevel analysis using the European Values Study.

    Science.gov (United States)

    Köneke, Vanessa

    2014-12-20

    This study tests how various kinds of trust impact attitudes toward euthanasia among the general public. The indication that trust might have an impact on euthanasia attitudes is based on the slippery slope argument, which asserts that allowing euthanasia might lead to abuses and involuntary deaths. Adopting this argument usually leads to less positive attitudes towards euthanasia. Tying in with this, it is assumed here that greater trust diminishes such slippery slope fears, and thereby increases euthanasia acceptance. The effects of various trust indicators on euthanasia acceptance were tested using multilevel analysis, and data from the European Values Study 2008 (N = 49,114, 44 countries). More precisely, the influence of people's general levels of trust in other people, and their confidence in the health care system, were measured--both at the individual and at the country level. Confidence in the state and the press were accounted for as well, since both institutions might monitor and safeguard euthanasia practices. It was shown that the level of trust in a country was strongly positively linked to euthanasia attitudes, both for general trust and for confidence in health care. In addition, within countries, people who perceived their fellow citizens as trustworthy, and who had confidence in the press, were more supportive of euthanasia than their less trusting counterparts. The pattern was, however, not true for confidence in the state and for confidence in the health care system at the individual level. Notably, all confirmative effects held, even when other variables such as religiosity, education, and values regarding autonomy were controlled for. Trust seems to be a noteworthy construct to explain differences in attitudes towards euthanasia, especially when drawing cross-country comparisons. Therefore, it should be added to the existing literature on correlates of euthanasia attitudes.

  10. Covariate analysis of bivariate survival data

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, L.E.

    1992-01-01

    The methods developed are used to analyze the effects of covariates on bivariate survival data when censoring and ties are present. The proposed method provides models for bivariate survival data that include differential covariate effects and censored observations. The proposed models are based on an extension of the univariate Buckley-James estimators which replace censored data points by their expected values, conditional on the censoring time and the covariates. For the bivariate situation, it is necessary to determine the expectation of the failure times for one component conditional on the failure or censoring time of the other component. Two different methods have been developed to estimate these expectations. In the semiparametric approach these expectations are determined from a modification of Burke's estimate of the bivariate empirical survival function. In the parametric approach censored data points are also replaced by their conditional expected values where the expected values are determined from a specified parametric distribution. The model estimation will be based on the revised data set, comprised of uncensored components and expected values for the censored components. The variance-covariance matrix for the estimated covariate parameters has also been derived for both the semiparametric and parametric methods. Data from the Demographic and Health Survey was analyzed by these methods. The two outcome variables are post-partum amenorrhea and breastfeeding; education and parity were used as the covariates. Both the covariate parameter estimates and the variance-covariance estimates for the semiparametric and parametric models will be compared. In addition, a multivariate test statistic was used in the semiparametric model to examine contrasts. The significance of the statistic was determined from a bootstrap distribution of the test statistic.

  11. On the Usefulness of a Multilevel Logistic Regression Approach to Person-Fit Analysis

    Science.gov (United States)

    Conijn, Judith M.; Emons, Wilco H. M.; van Assen, Marcel A. L. M.; Sijtsma, Klaas

    2011-01-01

    The logistic person response function (PRF) models the probability of a correct response as a function of the item locations. Reise (2000) proposed to use the slope parameter of the logistic PRF as a person-fit measure. He reformulated the logistic PRF model as a multilevel logistic regression model and estimated the PRF parameters from this…

  12. Multilevel Analysis of the Effects of Antidiscrimination Policies on Earnings by Sexual Orientation

    Science.gov (United States)

    Klawitter, Marieka

    2011-01-01

    This study uses the 2000 U.S. Census data to assess the impact of antidiscrimination policies for sexual orientation on earnings for gays and lesbians. Using a multilevel model allows estimation of the effects of state and local policies on earnings and of variation in the effects of sexual orientation across local labor markets. The results…

  13. When Cannabis Is Available and Visible at School--A Multilevel Analysis of Students' Cannabis Use

    Science.gov (United States)

    Kuntsche, Emmanuel

    2010-01-01

    Aims: To investigate the links between the visibility of cannabis use in school (measured by teachers' reports of students being under the influence of cannabis on school premises), the proportion of cannabis users in the class, perceived availability of cannabis, as well as adolescent cannabis use. Methods: A multilevel regression model was…

  14. A Multi-Level Analysis of Risk Factors for Campylobacter spp. in Broiler Chickens in Iceland

    Science.gov (United States)

    Introduction We carried out a longitudinal study of the broiler industry in Iceland between May 2001 and September 2004. Using multi-level statistical methods, our objective was to determine which aspects of the birds, their management and/or their housing may be most useful for applying interventi...

  15. Using Multilevel Factor Analysis with Clustered Data: Investigating the Factor Structure of the Positive Values Scale

    Science.gov (United States)

    Huang, Francis L.; Cornell, Dewey G.

    2016-01-01

    Advances in multilevel modeling techniques now make it possible to investigate the psychometric properties of instruments using clustered data. Factor models that overlook the clustering effect can lead to underestimated standard errors, incorrect parameter estimates, and model fit indices. In addition, factor structures may differ depending on…

  16. Perceived Learning Environment and Students' Emotional Experiences: A Multilevel Analysis of Mathematics Classrooms

    Science.gov (United States)

    Frenzel, Anne C.; Pekrun, Reinhard; Goetz, Thomas

    2007-01-01

    A multilevel approach was used to analyze relationships between perceived classroom environments and emotions in mathematics. Based on Pekrun's (2000) [A social-cognitive, control-value theory of achievement emotions. In J. Heckhausen (Ed.), Motivational psychology of human development (pp. 143-163)] social-cognitive, control-value theory of…

  17. Does the Organization Matter? A Multilevel Analysis of Organizational Effects in Homeless Service Innovations

    Science.gov (United States)

    Cronley, Courtney; Patterson, David A.

    2012-01-01

    This study examined the effects of organizational culture on staff members' use of management information systems ("N" = 142) within homeless service organizations ("N" = 24), using a multilevel model. The Organizational Social Context Questionnaire was used to measure organizational culture, defined by three sub-constructs: (1) proficiency, (2)…

  18. School Climate as a Predictor of Incivility and Bullying among Public School Employees: A Multilevel Analysis

    Science.gov (United States)

    Powell, Joshua E.; Powell, Anna L.; Petrosko, Joseph M.

    2015-01-01

    We surveyed public school educators on the workplace incivility and workplace bullying they experienced and obtained their ratings of the organizational climate of the school. We used multilevel modeling to determine the effects of individual-level and school-level predictors. Ratings of school climate were significantly related to incivility and…

  19. On the Usefulness of a Multilevel Logistic Regression Approach to Person-Fit Analysis

    Science.gov (United States)

    Conijn, Judith M.; Emons, Wilco H. M.; van Assen, Marcel A. L. M.; Sijtsma, Klaas

    2011-01-01

    The logistic person response function (PRF) models the probability of a correct response as a function of the item locations. Reise (2000) proposed to use the slope parameter of the logistic PRF as a person-fit measure. He reformulated the logistic PRF model as a multilevel logistic regression model and estimated the PRF parameters from this…

  20. Parent Involvement and Science Achievement: A Cross-Classified Multilevel Latent Growth Curve Analysis

    Science.gov (United States)

    Johnson, Ursula Y.; Hull, Darrell M.

    2014-01-01

    The authors examined science achievement growth at Grades 3, 5, and 8 and parent school involvement at the same time points using the Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999. Data were analyzed using cross-classified multilevel latent growth curve modeling with time invariant and varying covariates. School-based…

  1. Explaining ethnic polarization over attitudes towards minority rights in Eastern Europe : a multilevel analysis

    NARCIS (Netherlands)

    Evans, Geoffrey; Need, Ariana

    2002-01-01

    This paper examines divisions between majority and minority ethnic groups over attitudes towards minority rights in 13 East European societies. Using national sample surveys and multilevel models, we test the effectiveness of competing explanations of ethnic polarization in attitudes towards minorit

  2. Multilevel Analysis of the Effects of Antidiscrimination Policies on Earnings by Sexual Orientation

    Science.gov (United States)

    Klawitter, Marieka

    2011-01-01

    This study uses the 2000 U.S. Census data to assess the impact of antidiscrimination policies for sexual orientation on earnings for gays and lesbians. Using a multilevel model allows estimation of the effects of state and local policies on earnings and of variation in the effects of sexual orientation across local labor markets. The results…

  3. Does the Organization Matter? A Multilevel Analysis of Organizational Effects in Homeless Service Innovations

    Science.gov (United States)

    Cronley, Courtney; Patterson, David A.

    2012-01-01

    This study examined the effects of organizational culture on staff members' use of management information systems ("N" = 142) within homeless service organizations ("N" = 24), using a multilevel model. The Organizational Social Context Questionnaire was used to measure organizational culture, defined by three sub-constructs: (1) proficiency, (2)…

  4. When Cannabis Is Available and Visible at School--A Multilevel Analysis of Students' Cannabis Use

    Science.gov (United States)

    Kuntsche, Emmanuel

    2010-01-01

    Aims: To investigate the links between the visibility of cannabis use in school (measured by teachers' reports of students being under the influence of cannabis on school premises), the proportion of cannabis users in the class, perceived availability of cannabis, as well as adolescent cannabis use. Methods: A multilevel regression model was…

  5. Sensory cut-off point obtained from survival analysis statistics

    OpenAIRE

    Garitta, Lorena; Langohr, Klaus; Gómez Melis, Guadalupe; Hough, Guillermo; Beeren, Cindy

    2015-01-01

    In the present work we applied interval-censored survival analysis techniques to estimate sensory cut-off points based on consumer’s decision to accept or reject food products taking into account the inherent variability in sensory measurements. We compared the values obtained using this survival analysis methodology with those obtained by applying a previous regression based method. Cut-off point (COP) estimations were made for acid flavor in yogurt, strawberry flavor in a strawberry flav...

  6. Simplifying multivariate survival analysis using global score test methodology

    Science.gov (United States)

    Zain, Zakiyah; Aziz, Nazrina; Ahmad, Yuhaniz

    2015-12-01

    In clinical trials, the main purpose is often to compare efficacy between experimental and control treatments. Treatment comparisons often involve multiple endpoints, and this situation further complicates the analysis of survival data. In the case of tumor patients, endpoints concerning survival times include: times from tumor removal until the first, the second and the third tumor recurrences, and time to death. For each patient, these endpoints are correlated, and the estimation of the correlation between two score statistics is fundamental in derivation of overall treatment advantage. In this paper, the bivariate survival analysis method using the global score test methodology is extended to multivariate setting.

  7. Reentry survival analysis of tumbling metallic hollow cylinder

    Science.gov (United States)

    Sim, Hyung-seok; Kim, Kyu-hong

    2011-09-01

    The survival of orbital debris reentering the Earth's atmosphere is considered. The numerical approach of NASA's Object Reentry Survival Analysis Tool (ORSAT) is reviewed, and a new equation accounting for reradiation heat loss of hollow cylindrical objects is presented. Based on these, a code called Survivability Analysis Program for Atmospheric Reentry (SAPAR) has been developed, and the new equation for reradiation heat loss is validated. Using this equation in conjunction with the formulation used in ORSAT, a comparative case study on the Delta-II second stage cylindrical tank is given, demonstrating that the analysis using the proposed equation is in good agreement with the actual recovered object when a practical value for thermal emissivity is used. A detailed explanation of the revised formulation is given, and additional simulation results are presented. Finally, discussions are made to address the applicability of the proposed equation to be incorporated in future survival analyses of orbital debris.

  8. A Framework for RFID Survivability Requirement Analysis and Specification

    Science.gov (United States)

    Zuo, Yanjun; Pimple, Malvika; Lande, Suhas

    Many industries are becoming dependent on Radio Frequency Identification (RFID) technology for inventory management and asset tracking. The data collected about tagged objects though RFID is used in various high level business operations. The RFID system should hence be highly available, reliable, and dependable and secure. In addition, this system should be able to resist attacks and perform recovery in case of security incidents. Together these requirements give rise to the notion of a survivable RFID system. The main goal of this paper is to analyze and specify the requirements for an RFID system to become survivable. These requirements, if utilized, can assist the system in resisting against devastating attacks and recovering quickly from damages. This paper proposes the techniques and approaches for RFID survivability requirements analysis and specification. From the perspective of system acquisition and engineering, survivability requirement is the important first step in survivability specification, compliance formulation, and proof verification.

  9. Approaches to learning as predictors of academic achievement: Results from a large scale, multi-level analysis

    DEFF Research Database (Denmark)

    Herrmann, Kim Jesper

    2017-01-01

    . Controlling for the effects of age, gender, and progression, we found that the students’ end-of-semester grade point averages were related negatively to a surface approach and positively to organised effort. Interestingly, the effect of the surface approach on academic achievement varied across programmes......The relationships between university students’ academic achievement and their approaches to learning and studying continuously attract scholarly attention. We report the results of an analysis in which multilevel linear modelling was used to analyse data from 3,626 Danish university students...

  10. Frogs and ponds: a multilevel analysis of the regulatory mode complementarity hypothesis.

    Science.gov (United States)

    Pierro, Antonio; Presaghi, Fabio; Higgins, E Tory; Klein, Kristen M; Kruglanski, Arie W

    2012-02-01

    Regulatory mode is a psychological construct pertaining to the self-regulatory orientation of individuals or teams engaged in goal pursuit. Locomotion, the desire for continuous progress or movement in goal pursuit, and assessment, the desire to critically evaluate and compare goals and means, are orthogonal regulatory modes. However, they are also complementary, in that both locomotion and assessment are necessary for effectual goal pursuit. In the present research, the authors sought to demonstrate that multilevel regulatory mode complementarity can positively affect individual-level performance on goal-relevant tasks. The authors recruited 289 employees (177 men, 112 women) from preexisting work teams in workplace organizations in Italy and obtained (a) employees' individual-level scores on the Regulatory Mode Scale and (b) supervisor ratings of each employee's work performance. The results supported the multilevel complementarity hypothesis for regulatory mode. Limitations and recommendations for future research are discussed.

  11. Survival analysis of cholangiocarcinoma: A 10-year experience in Malaysia

    Institute of Scientific and Technical Information of China (English)

    Ahmad Ramzi Yusoff; Mohd Muzammil Abdul Razak; Yoong Boon Koon; R Vijeyasingam; Siti Zuraidah Mahmud

    2012-01-01

    AIM: To investigate the clinical features and survival of patients treated for cholangiocarcinoma in our institution and to analyze the factors affecting their survival. METHODS: This retrospective cohort study assessed patients diagnosed with cholangiocarcinoma between January 1997 and December 2007 at the University Malaya Medical Centre in Malaysia. The clinical data and associated outcomes were collected using a structured proforma. RESULTS: Of the 69 patients diagnosed with cholangiocarcinoma, 38 (55%) were male; mean patient age was 61 years. Twelve patients(17%) had intrahepatic, 38 (55%) had perihilar and 19 (28%) had distal tumors. Only 12 patients underwent curative surgery, including seven R0 resections. Only one patient died within 30 d after surgery. The overall median survival was 4 mo, whereas the median survival of R0 resected patients was 16 mo. The overall 1-, 2- and 3-year cumulative survival rates were 67%, 17% and 17%, respectively. Survival rates were significantly associated with curative resection (P= 0.002), intrahepatic tumor (P = 0.003), negative margin status (P = 0.013), early tumor stage (P = 0.016), higher tumor differentiation (P = 0.032) and absence of jaundice (P = 0.038). Multivariate analysis showed that tumor location was a significant independent predictor of patient survival. CONCLUSION: Curative, margin-negative resection of early stage, well-differentiated intrahepatic tumors is associated with improved patient survival.

  12. A brief conceptual tutorial of multilevel analysis in social epidemiology: using measures of clustering in multilevel logistic regression to investigate contextual phenomena

    DEFF Research Database (Denmark)

    Merlo, J; Chaix, B; Ohlsson, H

    2006-01-01

    STUDY OBJECTIVE: In social epidemiology, it is easy to compute and interpret measures of variation in multilevel linear regression, but technical difficulties exist in the case of logistic regression. The aim of this study was to present measures of variation appropriate for the logistic case...... in a didactic rather than a mathematical way. Design and PARTICIPANTS: Data were used from the health survey conducted in 2000 in the county of Scania, Sweden, that comprised 10 723 persons aged 18-80 years living in 60 areas. Conducting multilevel logistic regression different techniques were applied...... propensity areas with the area educational level. The sorting out index was equal to 82%. CONCLUSION: Measures of variation in logistic regression should be promoted in social epidemiological and public health research as efficient means of quantifying the importance of the context of residence...

  13. A brief conceptual tutorial of multilevel analysis in social epidemiology: using measures of clustering in multilevel logistic regression to investigate contextual phenomena

    DEFF Research Database (Denmark)

    Merlo, J; Chaix, B; Ohlsson, H;

    2006-01-01

    in a didactic rather than a mathematical way. Design and PARTICIPANTS: Data were used from the health survey conducted in 2000 in the county of Scania, Sweden, that comprised 10 723 persons aged 18-80 years living in 60 areas. Conducting multilevel logistic regression different techniques were applied...... propensity areas with the area educational level. The sorting out index was equal to 82%. CONCLUSION: Measures of variation in logistic regression should be promoted in social epidemiological and public health research as efficient means of quantifying the importance of the context of residence......STUDY OBJECTIVE: In social epidemiology, it is easy to compute and interpret measures of variation in multilevel linear regression, but technical difficulties exist in the case of logistic regression. The aim of this study was to present measures of variation appropriate for the logistic case...

  14. Perceived learning environment and students emotional experiences : a multilevel analysis of mathematics classrooms

    OpenAIRE

    Frenzel, Anne C.; Pekrun, Reinhard; Götz, Thomas

    2007-01-01

    A multilevel approach was used to analyse relationships between perceived classroom environments and emotions in mathematics. Based on Pekrun s (2000) [A social cognitive, control-value theory of achievement emotions. In J. Heckhausen (Ed.), Motivational psychology of human development (pp. 143-163)] social-cognitive, control-value theory of achievement emotions, we hypothesized that environmental characteristics conveying control and value to the students would be related to their experience...

  15. Determinants of gastric cancer screening attendance in Korea: a multi-level analysis

    OpenAIRE

    Chang, Yunryong; Cho, Belong; Son, Ki Young; Shin, Dong Wook; Shin, Hosung; Yang, Hyung-Kook; Shin, Aesun; Yoo, Keun-Young

    2015-01-01

    Background We aimed to assess individual and area-level determinants of gastric cancer screening participation. Method Data on gastric cancer screening and individual-level characteristics were obtained from the 2007–2009 Fourth Korea National Health and Nutrition Examination Survey. The area-level variables were collected from the 2005 National Population Census, 2008 Korea Medical Association, and 2010 National Health Insurance Corporation. The data were analyzed using multilevel logistic r...

  16. Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: a meta-analysis of clinical and radiological outcomes.

    Science.gov (United States)

    Lee, Chang-Hyun; Lee, Jaebong; Kang, James D; Hyun, Seung-Jae; Kim, Ki-Jeong; Jahng, Tae-Ahn; Kim, Hyun-Jib

    2015-06-01

    OBJECT Posterior cervical surgery, expansive laminoplasty (EL) or laminectomy followed by fusion (LF), is usually performed in patients with multilevel (≥ 3) cervical spondylotic myelopathy (CSM). However, the superiority of either of these techniques is still open to debate. The aim of this study was to compare clinical outcomes and postoperative kyphosis in patients undergoing EL versus LF by performing a meta-analysis. METHODS Included in the meta-analysis were all studies of EL versus LF in adults with multilevel CSM in MEDLINE (PubMed), EMBASE, and the Cochrane library. A random-effects model was applied to pool data using the mean difference (MD) for continuous outcomes, such as the Japanese Orthopaedic Association (JOA) grade, the cervical curvature index (CCI), and the visual analog scale (VAS) score for neck pain. RESULTS Seven studies comprising 302 and 290 patients treated with EL and LF, respectively, were included in the final analyses. Both treatment groups showed slight cervical lordosis and moderate neck pain in the baseline state. Both groups were similarly improved in JOA grade (MD 0.09, 95% CI -0.37 to 0.54, p = 0.07) and neck pain VAS score (MD -0.33, 95% CI -1.50 to 0.84, p = 0.58). Both groups evenly lost cervical lordosis. In the LF group lordosis seemed to be preserved in long-term follow-up studies, although the difference between the 2 treatment groups was not statistically significant. CONCLUSIONS Both EL and LF lead to clinical improvement and loss of lordosis evenly. There is no evidence to support EL over LF in the treatment of multilevel CSM. Any superiority between EL and LF remains in question, although the LF group shows favorable long-term results.

  17. Regional inequality and vaccine uptake: a multilevel analysis of the 2007 Welfare Monitoring Survey in Malawi

    Directory of Open Access Journals (Sweden)

    Abebe Dawit Shawel

    2012-12-01

    Full Text Available Abstract Background A significant part of childhood mortality can be prevented given the existence of a well functioning health care system that can deliver vaccines to children during their first year of life. This study assesses immunization differentials between regions in Malawi, and attempts to relate regional disparities in immunization to factors on individual, household and village level. Method We used data from the 2007 Welfare Monitoring Survey which includes 18 251 children ages 10–60 months. Multilevel logistic regression models were applied for data analysis. Results Major differences in full vaccine coverage (children receiving all of the 9 recommended vaccines were documented between the 27 official regions, called districts, of Malawi. The vaccine coverage among regions varied from 2% to 74% when all children 10 – 60 months old were included. Vaccine coverage was significantly higher for women that had their delivery attended by a midwife/nurse, or gave birth at a hospital or maternity clinic. Regions with a high percentage of deliveries attended by health personnel were also characterized by a higher coverage. Characteristics of health care utilization on the individual level could in part account for the observed regional variations in coverage. Several factors related to socio-demographic characteristics of individuals and households were significantly correlated with coverage (child’s age, illiteracy, income, water and sanitary conditions, implying a lower coverage among the most vulnerable parts of the population. However, these factors could only to a minor extent account for the regional variation in coverage. Conclusions The persistent regional inequalities suggest that the low immunization coverage in Malawi is less likely to be a result of geographical clustering of social groups with difficult level-of living conditions. Although the mean vaccine coverage in Malawi is low, some regions have succeeded in reaching

  18. Bayesian analysis of a disability model for lung cancer survival.

    Science.gov (United States)

    Armero, C; Cabras, S; Castellanos, M E; Perra, S; Quirós, A; Oruezábal, M J; Sánchez-Rubio, J

    2016-02-01

    Bayesian reasoning, survival analysis and multi-state models are used to assess survival times for Stage IV non-small-cell lung cancer patients and the evolution of the disease over time. Bayesian estimation is done using minimum informative priors for the Weibull regression survival model, leading to an automatic inferential procedure. Markov chain Monte Carlo methods have been used for approximating posterior distributions and the Bayesian information criterion has been considered for covariate selection. In particular, the posterior distribution of the transition probabilities, resulting from the multi-state model, constitutes a very interesting tool which could be useful to help oncologists and patients make efficient and effective decisions.

  19. [Survival analysis of 104 cases of osteosarcoma with lung metastases].

    Science.gov (United States)

    Ren, J; Xu, Y F; Kuang, T H; Chen, J; Liu, Y X

    2017-04-23

    Objective: To investigate the prognosis of osteosarcoma patients with lung metastases and its correlated factors. Methods: The clinical data of 104 osteosarcoma patients with lung metastasis from April 2007 to September 2015 were retrospectively analyzed. Univariate analysis was performed using Kaplan-Meier and Log rank test. Multivariate Cox regression was applied to analyze independent prognostic factor for patient survival. Results: The one-year, two-year and five-year survival rates of the 104 osteosarcoma patients with lung pulmonary metastasis were 93.3%, 61.5% and 11.5%, respectively, and the median survival time was 33 months. The univariate analysis revealed that number of lung metastases, objective response of first-line chemotherapy and therapeutic methods for lung metastases were significant prognostic factors for patient survival, whereas gender, age, time to lung metastasis and time to other metastasis were not (P>0.05). The multivariate analysis indicated that number of lung metastases, objective response of first-line chemotherapy and therapeutic methods for lung metastases were independent significant prognostic factors for patient survival. Conclusions: The prognosis of osteosarcoma patients with advanced lung metastases and active treatment is better. Surgery and adjuvant chemotherapy could effectively prolong survival time for osteosarcoma patients with pulmonary metastasis.

  20. Survival analysis with incomplete genetic data.

    Science.gov (United States)

    Lin, D Y

    2014-01-01

    Genetic data are now collected frequently in clinical studies and epidemiological cohort studies. For a large study, it may be prohibitively expensive to genotype all study subjects, especially with the next-generation sequencing technology. Two-phase sampling, such as case-cohort and nested case-control sampling, is cost-effective in such settings but entails considerable analysis challenges, especially if efficient estimators are desired. Another type of missing data arises when the investigators are interested in the haplotypes or the genetic markers that are not on the genotyping platform used for the current study. Valid and efficient analysis of such missing data is also interesting and challenging. This article provides an overview of these issues and outlines some directions for future research.

  1. Loading Analysis of Modular Multi-level Converter for Offshore High-voltage DC Application under Various Grid Faults

    DEFF Research Database (Denmark)

    Liu, Hui; Ma, Ke; Loh, Poh Chiang;

    2016-01-01

    The modular multi-level converter has become an interesting candidate in high-voltage DC systems due to its higher voltage levels and modular construction. Low-voltage ride-through is an important grid requirement for modular multi-level converter–high-voltage DC since not only causes control...... challenges but may also result in overstressed components for the modular multi-level converter. However, the thermal loading of the modular multi-level converter under various grid faults has not yet been clarified. In this article, the power loss and thermal performance of the modular multi-level converter...... during grid voltage dips are studied. The impacts of two typical grid faults to the modular multi-level converter in terms of operating and loading conditions are analytically researched and simulated. It has been found that the operating and loading conditions of the modular multi-level converter under...

  2. Survival Analysis of Fatigue and Rutting Failures in Asphalt Pavements

    Directory of Open Access Journals (Sweden)

    Pabitra Rajbongshi

    2016-01-01

    Full Text Available Fatigue and rutting are two primary failure mechanisms in asphalt pavements. The evaluations of fatigue and rutting performances are significantly uncertain due to large uncertainties involved with the traffic and pavement life parameters. Therefore, deterministically it is inadequate to predict when an in-service pavement would fail. Thus, the deterministic failure time which is known as design life (yr of pavement becomes random in nature. Reliability analysis of such time (t dependent random variable is the survival analysis of the structure. This paper presents the survival analysis of fatigue and rutting failures in asphalt pavement structures. It is observed that the survival of pavements with time can be obtained using the bathtub concept that contains a constant failure rate period and an increasing failure rate period. The survival function (S(t, probability density function (pdf, and probability distribution function (PDF of failure time parameter are derived using bathtub analysis. It is seen that the distribution of failure time follows three parametric Weibull distributions. This paper also works out to find the most reliable life (YrR of pavement sections corresponding to any reliability level of survivability.

  3. Analysis of the mechanism of nucleosome survival during transcription.

    Science.gov (United States)

    Chang, Han-Wen; Kulaeva, Olga I; Shaytan, Alexey K; Kibanov, Mikhail; Kuznedelov, Konstantin; Severinov, Konstantin V; Kirpichnikov, Mikhail P; Clark, David J; Studitsky, Vasily M

    2014-02-01

    Maintenance of nucleosomal structure in the cell nuclei is essential for cell viability, regulation of gene expression and normal aging. Our previous data identified a key intermediate (a small intranucleosomal DNA loop, Ø-loop) that is likely required for nucleosome survival during transcription by RNA polymerase II (Pol II) through chromatin, and suggested that strong nucleosomal pausing guarantees efficient nucleosome survival. To evaluate these predictions, we analysed transcription through a nucleosome by different, structurally related RNA polymerases and mutant yeast Pol II having different histone-interacting surfaces that presumably stabilize the Ø-loop. The height of the nucleosomal barrier to transcription and efficiency of nucleosome survival correlate with the net negative charges of the histone-interacting surfaces. Molecular modeling and analysis of Pol II-nucleosome intermediates by DNase I footprinting suggest that efficient Ø-loop formation and nucleosome survival are mediated by electrostatic interactions between the largest subunit of Pol II and core histones.

  4. Survival Analysis of Patients with End Stage Renal Disease

    Science.gov (United States)

    Urrutia, J. D.; Gayo, W. S.; Bautista, L. A.; Baccay, E. B.

    2015-06-01

    This paper provides a survival analysis of End Stage Renal Disease (ESRD) under Kaplan-Meier Estimates and Weibull Distribution. The data were obtained from the records of V. L. MakabaliMemorial Hospital with respect to time t (patient's age), covariates such as developed secondary disease (Pulmonary Congestion and Cardiovascular Disease), gender, and the event of interest: the death of ESRD patients. Survival and hazard rates were estimated using NCSS for Weibull Distribution and SPSS for Kaplan-Meier Estimates. These lead to the same conclusion that hazard rate increases and survival rate decreases of ESRD patient diagnosed with Pulmonary Congestion, Cardiovascular Disease and both diseases with respect to time. It also shows that female patients have a greater risk of death compared to males. The probability risk was given the equation R = 1 — e-H(t) where e-H(t) is the survival function, H(t) the cumulative hazard function which was created using Cox-Regression.

  5. The Impact of School Connectedness and Teacher Support on Depressive Symptoms in Adolescents: A Multilevel Analysis.

    Science.gov (United States)

    Joyce, Hilary D; Early, Theresa J

    2014-04-01

    Using data from Waves I and II of the National Longitudinal Study of Adolescent Health (Add Health), this study examined the association between school connectedness and teacher support and depressive symptoms in a weighted sample of 11,852 adolescents from 132 schools. To account for the nested data, multilevel regression was utilized. The results indicated higher school connectedness and getting along with teachers were significantly associated with fewer depressive symptoms. Findings offer implications for school social work practice and future research. Suggestions for future research are described and strategies to enhance school connectedness and teacher support are discussed.

  6. Statistical models and methods for reliability and survival analysis

    CERN Document Server

    Couallier, Vincent; Huber-Carol, Catherine; Mesbah, Mounir; Huber -Carol, Catherine; Limnios, Nikolaos; Gerville-Reache, Leo

    2013-01-01

    Statistical Models and Methods for Reliability and Survival Analysis brings together contributions by specialists in statistical theory as they discuss their applications providing up-to-date developments in methods used in survival analysis, statistical goodness of fit, stochastic processes for system reliability, amongst others. Many of these are related to the work of Professor M. Nikulin in statistics over the past 30 years. The authors gather together various contributions with a broad array of techniques and results, divided into three parts - Statistical Models and Methods, Statistical

  7. A multilevel analysis of long-term psychological distress among Belarusians affected by the Chernobyl disaster.

    Science.gov (United States)

    Beehler, G P; Baker, J A; Falkner, K; Chegerova, T; Pryshchepava, A; Chegerov, V; Zevon, M; Bromet, E; Havenaar, J; Valdismarsdottir, H; Moysich, K B

    2008-11-01

    Radiation contamination and sociopolitical instability following the Chernobyl nuclear power plant disaster have had a profound impact on Belarus. To investigate the factors that impact long-term mental health outcomes of this population almost 20 years after the disaster. Cross-sectional study. In-person interviews were conducted with 381 men and women from two geographic areas of differing radiation contamination within Belarus. Participants completed surveys of demographics, psychosocial factors and psychological distress. Individual-level characteristics were combined with household-level measures of radiation contamination exposure and family characteristics to create multilevel predictive models of psychological distress. Between-household effects accounted for 20% of variability in depression and anxiety scores, but only 8% of variability in somatization scores. Degree of chronic daily stressors showed a significant positive relationship with psychological distress, whereas mastery/controllability showed a significant inverse relationship with distress. At household level, perceived family problems, but not level of residential radiation contamination, was the best predictor of distress. Multilevel modelling indicates that long-term psychological distress among Belarusians affected by the Chernobyl disaster is better predicted by stress-moderating psychosocial factors present in one's daily life than by level of residential radiation contamination.

  8. "Selfish" algorithm for optimizing the network survivability analysis

    CERN Document Server

    Poroseva, Svetlana V

    2012-01-01

    In Nature, the primary goal of any network is to survive. This is less obvious for engineering networks (electric power, gas, water, transportation systems etc.) that are expected to operate under normal conditions most of time. As a result, the ability of a network to withstand massive sudden damage caused by adverse events (or survivability) has not been among traditional goals in the network design. Reality, however, calls for the adjustment of design priorities. As modern networks develop toward increasing their size, complexity, and integration, the likelihood of adverse events increases too due to technological development, climate change, and activities in the political arena among other factors. Under such circumstances, a network failure has an unprecedented effect on lives and economy. To mitigate the impact of adverse events on the network operability, the survivability analysis must be conducted at the early stage of the network design. Such analysis requires the development of new analytical and ...

  9. Comprehensive multilevel in vivo and in vitro analysis of heart rate fluctuations in mice by ECG telemetry and electrophysiology.

    Science.gov (United States)

    Fenske, Stefanie; Pröbstle, Rasmus; Auer, Franziska; Hassan, Sami; Marks, Vanessa; Pauza, Danius H; Biel, Martin; Wahl-Schott, Christian

    2016-01-01

    The normal heartbeat slightly fluctuates around a mean value; this phenomenon is called physiological heart rate variability (HRV). It is well known that altered HRV is a risk factor for sudden cardiac death. The availability of genetic mouse models makes it possible to experimentally dissect the mechanism of pathological changes in HRV and its relation to sudden cardiac death. Here we provide a protocol that allows for a comprehensive multilevel analysis of heart rate (HR) fluctuations. The protocol comprises a set of techniques that include in vivo telemetry and in vitro electrophysiology of intact sinoatrial network preparations or isolated single sinoatrial node (SAN) cells. In vitro preparations can be completed within a few hours, with data acquisition within 1 d. In vivo telemetric ECG requires 1 h for surgery and several weeks for data acquisition and analysis. This protocol is of interest to researchers investigating cardiovascular physiology and the pathophysiology of sudden cardiac death.

  10. IMPLICATIONS OF THE EU MULTI-LEVEL GOVERNANCE IN THE FIELD OF COMPETITION POLICY – A COMPARATIVE ANALYSIS OF THE CHARACTERISTICS OF COHESION AND COMPETITION POLICIES

    Directory of Open Access Journals (Sweden)

    Florin Bonciu

    2011-09-01

    Full Text Available The paper aims at analyzing the intrinsic characteristics of the European Union and to show that these characteristics objectively require the implementation of multi-level governance. A comparative analysis of the European Union’s cohesion and competition policy is presented from the point of view of these elements. Further on, given the implications of the economic crisis, the paper explores the possible translation from multi-level governance to polycentric governance and its implications for the cohesion and competition policies.

  11. Indiana Emergent Bilingual Student Time to Reclassification: A Survival Analysis

    Science.gov (United States)

    Burke, April M.; Morita-Mullaney, Trish; Singh, Malkeet

    2016-01-01

    In this study, we employed a discrete-time survival analysis model to examine Indiana emergent bilingual time to reclassification as fluent English proficient. The data consisted of five years of statewide English language proficiency scores. Indiana has a large and rapidly growing Spanish-speaking emergent bilingual population, and these students…

  12. Integrative Genomics with Mediation Analysis in a Survival Context

    Directory of Open Access Journals (Sweden)

    Szilárd Nemes

    2013-01-01

    Full Text Available DNA copy number aberrations (DCNA and subsequent altered gene expression profiles may have a major impact on tumor initiation, on development, and eventually on recurrence and cancer-specific mortality. However, most methods employed in integrative genomic analysis of the two biological levels, DNA and RNA, do not consider survival time. In the present note, we propose the adoption of a survival analysis-based framework for the integrative analysis of DCNA and mRNA levels to reveal their implication on patient clinical outcome with the prerequisite that the effect of DCNA on survival is mediated by mRNA levels. The specific aim of the paper is to offer a feasible framework to test the DCNA-mRNA-survival pathway. We provide statistical inference algorithms for mediation based on asymptotic results. Furthermore, we illustrate the applicability of the method in an integrative genomic analysis setting by using a breast cancer data set consisting of 141 invasive breast tumors. In addition, we provide implementation in R.

  13. The Quadratic Relationship between Socioeconomic Status and Learning Performance in China by Multilevel Analysis: Implications for Policies to Foster Education Equity

    Science.gov (United States)

    Zhao, Ningning; Valcke, Martin; Desoete, Annemie; Verhaeghe, JeanPierre

    2012-01-01

    The purpose of the present study is to explore the relationship between family socioeconomic status and mathematics performance on the base of a multi-level analysis involving a large sample of Chinese primary school students. A weak relationship is found between socioeconomic status and performance in the Chinese context. The relationship does…

  14. Multilevel Latent Class Analysis for Large-Scale Educational Assessment Data: Exploring the Relation between the Curriculum and Students' Mathematical Strategies

    Science.gov (United States)

    Fagginger Auer, Marije F.; Hickendorff, Marian; Van Putten, Cornelis M.; Béguin, Anton A.; Heiser, Willem J.

    2016-01-01

    A first application of multilevel latent class analysis (MLCA) to educational large-scale assessment data is demonstrated. This statistical technique addresses several of the challenges that assessment data offers. Importantly, MLCA allows modeling of the often ignored teacher effects and of the joint influence of teacher and student variables.…

  15. Multilevel modelling and time series analysis in traffic safety research : methodology. SafetyNet, Building the European Road Safety Observatory, Workpackage 7, Deliverable 7.4.

    NARCIS (Netherlands)

    Antoniou, C. Brandstaetter, C. Bergel, R. Cherfi, M. Bijleveld, F. Commandeur, J.J.F. Blois, C. de Dupont, E. Gatscha, M. Martensen, H. Papadimitriou, E. Vanlaar, W. & Yannis, G.

    2007-01-01

    This deliverable gives the theoretical background for the two families of analyses, multilevel and time series analysis. For each technique the objectives, detailed model formulation, and assumptions are described and subsequently the technique is illustrated with an empirical example relevant to

  16. The Association between Overweight and School Policies on Physical Activity: A Multilevel Analysis among Elementary School Youth in the PLAY-On Study

    Science.gov (United States)

    Leatherdale, Scott T.

    2010-01-01

    The objective is to examine school-level program and policy characteristics and student-level behavioural characteristics associated with being overweight. Multilevel logistic regression analysis were used to examine the school- and student-level characteristics associated with the odds of a student being overweight among 1264 Grade 5-8 students…

  17. A Multilevel Analysis of the Compositional and Contextual Association of Social Capital and Subjective Well-Being in Seoul, South Korea

    Science.gov (United States)

    Han, Sehee; Kim, Heaseung; Lee, Hee-Sun

    2013-01-01

    The purpose of this study is to examine the association between social capital and subjective well-being (life satisfaction) by using multilevel analysis considering both individual and area-level social capital while adjusting for various control variables at multiple-levels in Seoul, South Korea. The data was from the 2010 (Wave 2) Seoul Welfare…

  18. Neighborhood socioeconomic disadvantage, individual wealth status and patterns of delivery care utilization in Nigeria: a multilevel discrete choice analysis

    Directory of Open Access Journals (Sweden)

    Aremu O

    2011-07-01

    Full Text Available Olatunde Aremu1,2, Stephen Lawoko1, Koustuv Dalal1,31Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden; 2College of Medicine, University of Ibadan, Ibadan, Nigeria; 3Department of Medicine and Health Sciences, Centre for Health Technology Assessment, Linköping University, SwedenBackground: High maternal mortality continues to be a major public health problem in most part of the developing world, including Nigeria. Understanding the utilization pattern of maternal healthcare services has been accepted as an important factor for reducing maternal deaths. This study investigates the effect of neighborhood and individual socioeconomic position on the utilization of different forms of place of delivery among women of reproductive age in Nigeria.Methods: A population-based multilevel discrete choice analysis was performed using the most recent population-based 2008 Nigerian Demographic and Health Surveys data of women aged between 15 and 49 years. The analysis was restricted to 15,162 ever-married women from 888 communities across the 36 states of the federation including the Federal Capital Territory of Abuja.Results: The choice of place to deliver varies across the socioeconomic strata. The results of the multilevel discrete choice models indicate that with every other factor controlled for, the household wealth status, women's occupation, women's and partner's high level of education attainment, and possession of health insurance were associated with use of private and government health facilities for child birth relative to home delivery. The results also show that higher birth order and young maternal age were associated with use of home delivery. Living in a highly socioeconomic disadvantaged neighborhood is associated with home birth compared with the patronage of government health facilities. More specifically, the result revealed that choice of facility-based delivery is clustered around the neighborhoods

  19. PARALLEL ADAPTIVE MULTILEVEL SAMPLING ALGORITHMS FOR THE BAYESIAN ANALYSIS OF MATHEMATICAL MODELS

    KAUST Repository

    Prudencio, Ernesto

    2012-01-01

    In recent years, Bayesian model updating techniques based on measured data have been applied to many engineering and applied science problems. At the same time, parallel computational platforms are becoming increasingly more powerful and are being used more frequently by the engineering and scientific communities. Bayesian techniques usually require the evaluation of multi-dimensional integrals related to the posterior probability density function (PDF) of uncertain model parameters. The fact that such integrals cannot be computed analytically motivates the research of stochastic simulation methods for sampling posterior PDFs. One such algorithm is the adaptive multilevel stochastic simulation algorithm (AMSSA). In this paper we discuss the parallelization of AMSSA, formulating the necessary load balancing step as a binary integer programming problem. We present a variety of results showing the effectiveness of load balancing on the overall performance of AMSSA in a parallel computational environment.

  20. Three frameworks to predict physical activity behavior in middle school inclusive physical education: a multilevel analysis.

    Science.gov (United States)

    Jin, Jooyeon; Yun, Joonkoo

    2013-07-01

    The purpose of this study was to examine three frameworks, (a) process-product, (b) student mediation, and (c) classroom ecology, to understand physical activity (PA) behavior of adolescents with and without disabilities in middle school inclusive physical education (PE). A total of 13 physical educators teaching inclusive PE and their 503 students, including 22 students with different disabilities, participated in this study. A series of multilevel regression analyses indicated that physical educators' teaching behavior and students' implementation intentions play important roles in promoting the students' PA in middle school inclusive PE settings when gender, disability, lesson content, instructional model, and class location are considered simultaneously. The findings suggest that the ecological framework should be considered to effectively promote PA of adolescents with and without disabilities in middle school PE classes.

  1. Data Model Approach And Markov Chain Based Analysis Of Multi-Level Queue Scheduling

    Directory of Open Access Journals (Sweden)

    Diwakar Shukla

    2010-01-01

    Full Text Available There are many CPU scheduling algorithms inliterature like FIFO, Round Robin, Shortest-Job-First and so on.The Multilevel-Queue-Scheduling is superior to these due to itsbetter management of a variety of processes. In this paper, aMarkov chain model is used for a general setup of Multilevelqueue-scheduling and the scheduler is assumed to performrandom movement on queue over the quantum of time.Performance of scheduling is examined through a rowdependent data model. It is found that with increasing value of αand d, the chance of system going over the waiting state reduces.At some of the interesting combinations of α and d, it diminishesto zero, thereby, provides us some clue regarding better choice ofqueues over others for high priority jobs. It is found that ifqueue priorities are added in the scheduling intelligently thenbetter performance could be obtained. Data model helpschoosing appropriate preferences.

  2. Multilevel analysis of workplace and individual risk factors for long-term sickness absence

    DEFF Research Database (Denmark)

    Labriola, Merete; Christensen, Karl B; Lund, Thomas

    2006-01-01

    OBJECTIVE: The objective of this study was to examine if psychosocial and physical work-environment factors predict long-term sickness absence (>8 weeks) at both the individual and the workplace level. MATERIAL AND METHODS: Data were collected in a prospective study in 52 Danish workplaces....... Psychosocial factors were aggregated as workplace means. We used multilevel logistic regression models with psychosocial factors as predictors of long-term sickness absence over 5 years based on data from a national absence register. RESULTS: Long-term sickness absence was predicted by physical work......-environment factors at the individual level and psychosocial work environment factors at the workplace level. Interaction between the individual physical and workplace-level psychosocial risk factors was found. CONCLUSION: Workplace-based absence reduction interventions can be enhanced by concurrently addressing...

  3. Racial segregation and maternal smoking during pregnancy: a multilevel analysis using the racial segregation interaction index.

    Science.gov (United States)

    Yang, Tse-Chuan; Shoff, Carla; Noah, Aggie J; Black, Nyesha; Sparks, Corey S

    2014-04-01

    Drawing from both the place stratification and ethnic enclave perspectives, we use multilevel modeling to investigate the relationships between women's race/ethnicity (i.e., non-Hispanic white, non-Hispanic black, Asian, and Hispanic) and maternal smoking during pregnancy, and examine if these relationships are moderated by racial segregation in the continental United States. The results show that increased interaction with whites is associated with increased probability of maternal smoking during pregnancy, and racial segregation moderates the relationships between race/ethnicity and maternal smoking. Specifically, living in a less racially segregated area is related to a lower probability of smoking during pregnancy for black women, but it could double and almost triple the probability of smoking for Asian women and Hispanic women, respectively. Our findings provide empirical evidence for both the place stratification and ethnic enclave perspectives.

  4. A Survival Analysis of Student Mobility and Retention in Indiana Charter Schools

    Directory of Open Access Journals (Sweden)

    Holmes Finch

    2009-10-01

    Full Text Available Research has demonstrated that high rates of student mobility are associated with a range of negative academic outcomes, both for students who leave their schools and those who remain behind. The current study focused on mobility among those enrolled in charter schools in the state of Indiana. A multilevel Cox Proportional Hazards survival analysis model was used to identify significant predictors of student mobility within and from a state charter school system, using factors at both the student and school levels. Results indicated that initial student achievement upon first entering a charter school, student ethnicity, participation in a Title I funded program, and average years of teacher experience at the school were all associated with the decision to leave the charter. Specifically, students with higher initial achievement scores, those eligible for Title 1 services, and non-Caucasian students were more likely to leave charter schools prematurely. In addition, schools with a more experienced faculty had lower early departure rates than did those with less experienced teachers.

  5. Vulnerability survival analysis: a novel approach to vulnerability management

    Science.gov (United States)

    Farris, Katheryn A.; Sullivan, John; Cybenko, George

    2017-05-01

    Computer security vulnerabilities span across large, enterprise networks and have to be mitigated by security engineers on a routine basis. Presently, security engineers will assess their "risk posture" through quantifying the number of vulnerabilities with a high Common Vulnerability Severity Score (CVSS). Yet, little to no attention is given to the length of time by which vulnerabilities persist and survive on the network. In this paper, we review a novel approach to quantifying the length of time a vulnerability persists on the network, its time-to-death, and predictors of lower vulnerability survival rates. Our contribution is unique in that we apply the cox proportional hazards regression model to real data from an operational IT environment. This paper provides a mathematical overview of the theory behind survival analysis methods, a description of our vulnerability data, and an interpretation of the results.

  6. Prognostic and survival analysis of presbyopia: The healthy twin study

    Science.gov (United States)

    Lira, Adiyani; Sung, Joohon

    2015-12-01

    Presbyopia, a vision condition in which the eye loses its flexibility to focus on near objects, is part of ageing process which mostly perceptible in the early or mid 40s. It is well known that age is its major risk factor, while sex, alcohol, poor nutrition, ocular and systemic diseases are known as common risk factors. However, many other variables might influence the prognosis. Therefore in this paper we developed a prognostic model to estimate survival from presbyopia. 1645 participants which part of the Healthy Twin Study, a prospective cohort study that has recruited Korean adult twins and their family members based on a nation-wide registry at public health agencies since 2005, were collected and analyzed by univariate analysis as well as Cox proportional hazard model to reveal the prognostic factors for presbyopia while survival curves were calculated by Kaplan-Meier method. Besides age, sex, diabetes, and myopia; the proposed model shows that education level (especially engineering program) also contribute to the occurrence of presbyopia as well. Generally, at 47 years old, the chance of getting presbyopia becomes higher with the survival probability is less than 50%. Furthermore, our study shows that by stratifying the survival curve, MZ has shorter survival with average onset time about 45.8 compare to DZ and siblings with 47.5 years old. By providing factors that have more effects and mainly associate with presbyopia, we expect that we could help to design an intervention to control or delay its onset time.

  7. Racial disparities in context: a multilevel analysis of neighborhood variations in poverty and excess mortality among black populations in Massachusetts.

    Science.gov (United States)

    Subramanian, S V; Chen, Jarvis T; Rehkopf, David H; Waterman, Pamela D; Krieger, Nancy

    2005-02-01

    We analyzed neighborhood heterogeneity in associations among mortality, race/ethnicity, and area poverty. We performed a multilevel statistical analysis of Massachusetts all-cause mortality data for the period 1989 through 1991 (n=142836 deaths), modeled as 79813 cells (deaths and denominators cross-tabulated by age, gender, and race/ethnicity) at level 1 nested within 5532 block groups at level 2 within 1307 census tracts (CTs) at level 3. We also characterized CTs by percentage of the population living below poverty level. Neighborhood variation in mortality across CTs and block groups was not accounted for by these areas' age, gender, and racial/ethnic composition. Neighborhood variation in mortality was much greater for the Black population than for the White population, largely because of CT-level variation in poverty rates. Neighborhood heterogeneity in the relationship between mortality and race/ethnicity in Massachusetts is statistically significant and is closely related to CT-level variation in poverty.

  8. A Multilevel Analysis of the Relationship Between Cell Sharing, Staff-Prisoner Relationships, and Prisoners' Perceptions of Prison Quality.

    Science.gov (United States)

    Molleman, Toon; van Ginneken, Esther F J C

    2015-09-01

    Prisons worldwide operate under crowded conditions, in which prisoners are forced to share a cell. Few studies have looked at the relationship between cell sharing and the quality of prison life in Europe. This study aims to fill this gap with a multilevel analysis on the link between cell sharing and quality of prison life, using results from a Dutch prisoner survey. Findings show that cell sharing is associated with lower perceived prison quality, which is partially mediated by reduced quality of staff-prisoner relationships. Cell sharing thus undermines the Dutch penological philosophy, which considers staff-prisoner relationships to be at the heart of prisoner treatment and rehabilitation. It is recommended that prisoners are held in single rather than double cells.

  9. Study and Analysis of a Natural Reference Frame Current Controller for a Multi-Level H-Bridge Power Converter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Iov, Florin; Zanchetta, P.;

    2008-01-01

    will be needed in order to control the power flow and to ensure proper and secure operation of this future grid with an increased level of renewable power. These power converters must be able to provide intelligent power management as well as ancillary services. This paper presents an analysis of the natural...... reference frame controller, based on proportional-resonant (PR) technique, for a multi-level H-bridge power converter for Universal and Flexible Power Management in Future Electricity Network. The proposed method is tested in terms of harmonic content in the Point of Common Coupling (PCC), voltage......To pave the way to a sustainable energy future based on a larger share of Distributed Generation (DG), there is a clear need to prepare the European electricity system for the large-scale integration of both renewable and other distributed energy sources. Advanced power electronic converters for DG...

  10. Revisiting causal neighborhood effects on individual ischemic heart disease risk: a quasi-experimental multilevel analysis among Swedish siblings.

    Science.gov (United States)

    Merlo, Juan; Ohlsson, Henrik; Chaix, Basile; Lichtenstein, Paul; Kawachi, Ichiro; Subramanian, S V

    2013-01-01

    Neighborhood socioeconomic disadvantage is associated to increased individual risk of ischemic heart disease (IHD). However, the value of this association for causal inference is uncertain. Moreover, neighborhoods are often defined by available administrative boundaries without evaluating in which degree these boundaries embrace a relevant socio-geographical context that condition individual differences in IHD risk. Therefore, we performed an analysis of variance, and also compared the associations obtained by conventional multilevel analyses and by quasi-experimental family-based design that provides stronger evidence for causal inference. Linking the Swedish Multi-Generation Register to several other national registers, we analyzed 184,931 families embracing 415,540 full brothers 45-64 years old in 2004, and residing in 8408 small-area market statistics (SAMS) considered as "neighborhoods" in our study. We investigated the association between low neighborhood income (categorized in groups by deciles) and IHD risk in the next four years. We distinguished between family mean and intrafamilial-centered low neighborhood income, which allowed us to investigate both unrelated individuals from different families and full brothers within families. We applied multilevel logistic regression techniques to obtain odds ratios (OR), variance partition coefficients (VPC) and 95% credible intervals (CI). In unrelated individuals a decile unit increase of low neighborhood income increased individual IHD risk (OR = 1.04, 95% CI: 1.03-1.07). In the intrafamilial analysis this association was reduced (OR = 1.02, 95% CI: 1.02-1.04). Low neighborhood income seems associated with IHD risk in middle-aged men. However, despite the family-based design, we cannot exclude residual confounding by genetic and non-shared environmental factors. Besides, the low neighborhood level VPC = 1.5% suggest that the SAMS are a rather inappropriate construct of the socio-geographic context that

  11. Childhood growth trajectories according to combinations of pregestational weight status and maternal smoking during pregnancy: a multilevel analysis.

    Science.gov (United States)

    Suzuki, Kohta; Sato, Miri; Zheng, Wei; Shinohara, Ryoji; Yokomichi, Hiroshi; Yamagata, Zentaro

    2015-01-01

    Pregestational weight status and maternal smoking during pregnancy are significantly associated with fetal and childhood growth. However, few studies have examined associations between childhood growth and combinations of these factors using multilevel analysis. This study aimed to describe differences in childhood growth trajectories according to these combinations, using data from a prospective cohort study in Japan. The study participants were 1,973 women and their singletons, who were born between April 1, 1991 and March 31, 2003. Children were categorized according to whether they were born to normal-weight, nonsmoking mothers (NN); normal-weight, smoking mothers (NS); underweight, nonsmoking mothers (UN); underweight, smoking mothers (US); overweight, nonsmoking mothers (ON); or overweight, smoking mothers (OS). Birth weight and anthropometric data were collected from 1,965 children at birth (99.6%), 1,655 aged 3 (83.9%), 1,527 aged 5 (77.4%), 1,497 aged 7-8 (75.9%), and 1,501 aged 9-10 (76.1%). Multilevel analysis examining both individual and age as different level variables according to sex was used to describe the trajectories of body mass index z scores for statistical analyses. Although children of the OS group were the leanest at birth, their body mass indices had increased rapidly by 3 years of age. Moreover, body mass index was also likely to increase in boys in the NS and ON groups. A different trend was observed in girls. Body mass index decreased from 5 years of age in girls in the US group. There were no remarkable differences in body mass index trajectories between children in the other groups. In conclusion, childhood growth trajectories differed according to combinations of pregestational weight status and maternal smoking during pregnancy. Further, there were sex-related differences in the associations between childhood growth and factor combinations.

  12. Neighborhood socioeconomic disadvantage, individual wealth status and patterns of delivery care utilization in Nigeria: a multilevel discrete choice analysis

    Science.gov (United States)

    Aremu, Olatunde; Lawoko, Stephen; Dalal, Koustuv

    2011-01-01

    Background High maternal mortality continues to be a major public health problem in most part of the developing world, including Nigeria. Understanding the utilization pattern of maternal healthcare services has been accepted as an important factor for reducing maternal deaths. This study investigates the effect of neighborhood and individual socioeconomic position on the utilization of different forms of place of delivery among women of reproductive age in Nigeria. Methods A population-based multilevel discrete choice analysis was performed using the most recent population-based 2008 Nigerian Demographic and Health Surveys data of women aged between 15 and 49 years. The analysis was restricted to 15,162 ever-married women from 888 communities across the 36 states of the federation including the Federal Capital Territory of Abuja. Results The choice of place to deliver varies across the socioeconomic strata. The results of the multilevel discrete choice models indicate that with every other factor controlled for, the household wealth status, women’s occupation, women’s and partner’s high level of education attainment, and possession of health insurance were associated with use of private and government health facilities for child birth relative to home delivery. The results also show that higher birth order and young maternal age were associated with use of home delivery. Living in a highly socioeconomic disadvantaged neighborhood is associated with home birth compared with the patronage of government health facilities. More specifically, the result revealed that choice of facility-based delivery is clustered around the neighborhoods. Conclusion Home delivery, which cuts across all socioeconomic strata, is a common practice among women in Nigeria. Initiatives that would encourage the appropriate use of healthcare facilities at little or no cost to the most disadvantaged should be accorded the utmost priority. PMID:21792338

  13. Measuring psychosocial environments using individual responses: an application of multilevel factor analysis to examining students in schools.

    Science.gov (United States)

    Dunn, Erin C; Masyn, Katherine E; Jones, Stephanie M; Subramanian, S V; Koenen, Karestan C

    2015-07-01

    Interest in understanding how psychosocial environments shape youth outcomes has grown considerably. School environments are of particular interest to prevention scientists as many prevention interventions are school-based. Therefore, effective conceptualization and operationalization of the school environment is critical. This paper presents an illustration of an emerging analytic method called multilevel factor analysis (MLFA) that provides an alternative strategy to conceptualize, measure, and model environments. MLFA decomposes the total sample variance-covariance matrix for variables measured at the individual level into within-cluster (e.g., student level) and between-cluster (e.g., school level) matrices and simultaneously models potentially distinct latent factor structures at each level. Using data from 79,362 students from 126 schools in the National Longitudinal Study of Adolescent to Adult Health (formerly known as the National Longitudinal Study of Adolescent Health), we use MLFA to show how 20 items capturing student self-reported behaviors and emotions provide information about both students (within level) and their school environment (between level). We identified four latent factors at the within level: (1) school adjustment, (2) externalizing problems, (3) internalizing problems, and (4) self-esteem. Three factors were identified at the between level: (1) collective school adjustment, (2) psychosocial environment, and (3) collective self-esteem. The finding of different and substantively distinct latent factor structures at each level emphasizes the need for prevention theory and practice to separately consider and measure constructs at each level of analysis. The MLFA method can be applied to other nested relationships, such as youth in neighborhoods, and extended to a multilevel structural equation model to better understand associations between environments and individual outcomes and therefore how to best implement preventive interventions.

  14. Situational drinking in private and public locations: A multilevel analysis of blood alcohol level in Finnish drinking occasions.

    Science.gov (United States)

    Mustonen, Heli; Mäkelä, Pia; Lintonen, Tomi

    2016-11-01

    The first aim was to estimate the extent to which the variation in alcohol use across specific drinking occasions arises from variation at the occasion level and from variation at the drinker level. The second aim was to identify characteristics of drinking situations that moderate or increase situational alcohol use beyond the influence of drinker-level characteristics. The general population aged 15-69 years in Finland was sampled randomly in 2008. The multilevel analysis was based on data from 1511 drinkers and 2933 drinking occasions that occurred in the 7 days before the interview. Alcohol use was operationalised as estimated blood alcohol level (BAL). Characteristics of drinking occasions included location, circumstance, company and timing. Drinker-level data included demographic and drinking pattern variables. Fifty-three percent of the variance in BAL was between occasions and 47% between respondents, for both women and men. With drinking patterns and demographic characteristics controlled for, the dominant characteristics of drinking occasions predisposing to greater intoxication were late-night drinking, across locations and for both genders. For private locations, predisposing characteristics included drinking on weekends for both genders and drinking with friends for men. Situational and drinker levels are equally important in determining the BAL in drinking occasions; therefore, prevention efforts should be targeted at both risky individuals and risky drinking occasions. Occasions occurring late at night, often at home and with friends, are a central challenge for targeting preventive efforts related to situational drinking.[Mustonen H, Mäkelä P, Lintonen T. Situational drinking in private and public locations: A multilevel analysis of blood alcohol level in Finnish drinking occasions. Drug Alcohol Rev 2016;35:772-784]. © 2016 Australasian Professional Society on Alcohol and other Drugs.

  15. Clinicopathologic and survival analysis of resected ampullary adenocarcinoma.

    Science.gov (United States)

    Doepker, Matthew P; Thompson, Zachary J; Centeno, Barbara A; Kim, Richard D; Wong, Joyce; Hodul, Pamela J

    2016-08-01

    Ampullary adenocarcinoma (AAC) is a rare neoplasm. We sought to determine the clinicopathologic factors contributing to the overall survival (OS) and recurrence-free (RFS) survival. Patients (pts) with resected AAC were identified from 1996 to 2015 and reviewed for clinicopathologic factors and correlated with outcome. We identified and evaluated 106 pts diagnosed with AAC. The median age was 70.2 years (range 41-86) and 60 (56.6%) were male. Overall, 105 pts (99.1%) had a pancreaticoduodenectomy. An R0 resection was achieved in 101 (95%) pts. Median follow-up was 19 months with a median OS of 49.3 months. Lymph node metastasis and poorly differentiated tumors adversely affected OS on multivariate analysis (MVA). Twenty patients (18.9%) developed recurrence. The median RFS was 27 months. RFS was adversely affected by lymph node count and metastasis, tumor differentiation, and histological subtype on MVA. Survival was not affected by the addition of adjuvant therapy. Retrieval of ≤12 lymph nodes and lymph node ratio ≥0.10 resulted in worse OS on Kaplan-Meier analysis. Our data show retrieval of ≤12 nodes, involvement of nodes with AAC, moderately or poorly differentiated tumors, and pancreaticobiliary subtype adversely affected survival, while the use of adjuvant therapy demonstrated no significant benefit. J. Surg. Oncol. 2016;114:170-175. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  16. Loading Analysis of Modular Multi-level Converter for Offshore High-voltage DC Application under Various Grid Faults

    DEFF Research Database (Denmark)

    Liu, Hui; Ma, Ke; Loh, Poh Chiang;

    2016-01-01

    The modular multi-level converter has become an interesting candidate in high-voltage DC systems due to its higher voltage levels and modular construction. Low-voltage ride-through is an important grid requirement for modular multi-level converter–high-voltage DC since not only causes control cha...... be of importance for the design of the cooling system....

  17. Civic participation and self-rated health: a cross-national multi-level analysis using the world value survey.

    Science.gov (United States)

    Kim, Saerom; Kim, Chang-yup; You, Myung Soon

    2015-01-01

    Civic participation, that which directly influences important decisions in our personal lives, is considered necessary for developing a society. We hypothesized that civic participation might be related to self-rated health status. We constructed a multi-level analysis using data from the World Value Survey (44 countries, n=50 859). People who participated in voting and voluntary social activities tended to report better subjective health than those who did not vote or participate in social activities, after controlling for socio-demographic factors at the individual level. A negative association with unconventional political activity and subjective health was found, but this effect disappeared in a subset analysis of only the 18 Organization for Economic Cooperation and Development (OECD) countries. Moreover, social participation and unconventional political participation had a statistically significant contextual association with subjective health status, but this relationship was not consistent throughout the analysis. In the analysis of the 44 countries, social participation was of borderline significance, while in the subset analysis of the OECD countries unconventional political participation was a stronger determinant of subjective health. The democratic index was a significant factor in determining self-rated health in both analyses, while public health expenditure was a significant factor in only the subset analysis. Despite the uncertainty of its mechanism, civic participation might be a significant determinant of the health status of a country.

  18. Return to work after trauma: A survival analysis

    Institute of Scientific and Technical Information of China (English)

    Masoumeh Abedzadeh-Kalahroudi; Ebrahim Razi; Mojtaba Sehat; Mohsen Asadi-Lari

    2017-01-01

    Purpose:To evaluate the return to work (RTW) rate,time and predictors among trauma patients using survival analysis.Methods:This cohort study was conducted with a three-month follow-up on 300 trauma patients hospitalized in Shahid Beheshti Hospital,Kashan,Iran in 2014.The data were collected through conducting interviews and referring to patients' medical records during their hospital stay and follow-up information at one & three months after discharge from hospital.Final analysis was conducted on the data retrieved from 273 patients.Data were analyzed by chi-square test,Mann-Whitney U test and survival analysis method.Results:The rate of RTW at the end of the first and the third follow-up months was respectively 21.6% and 61.2%.Survival analysis showed that the RTW time (Time between admission to first return to work) was significantly longer among patients with illiteracy,drug abuse,hospitalization history in the intensive care unit,low socioeconomic status,non-insurance coverage,longer hospital stay,multiple and severe injuries as well as severe disability.Conclusion:Our findings indicated that trauma has profound effects on the rate and time of RTW.Besides disability,many personal and clinical factors can affect the outcome of RTW.

  19. Multilevel Models: Conceptual Framework and Applicability

    Directory of Open Access Journals (Sweden)

    Roxana-Otilia-Sonia Hrițcu

    2015-10-01

    Full Text Available Individuals and the social or organizational groups they belong to can be viewed as a hierarchical system situated on different levels. Individuals are situated on the first level of the hierarchy and they are nested together on the higher levels. Individuals interact with the social groups they belong to and are influenced by these groups. Traditional methods that study the relationships between data, like simple regression, do not take into account the hierarchical structure of the data and the effects of a group membership and, hence, results may be invalidated. Unlike standard regression modelling, the multilevel approach takes into account the individuals as well as the groups to which they belong. To take advantage of the multilevel analysis it is important that we recognize the multilevel characteristics of the data. In this article we introduce the outlines of multilevel data and we describe the models that work with such data. We introduce the basic multilevel model, the two-level model: students can be nested into classes, individuals into countries and the general two-level model can be extended very easily to several levels. Multilevel analysis has begun to be extensively used in many research areas. We present the most frequent study areas where multilevel models are used, such as sociological studies, education, psychological research, health studies, demography, epidemiology, biology, environmental studies and entrepreneurship. We support the idea that since hierarchies exist everywhere, multilevel data should be recognized and analyzed properly by using multilevel modelling.

  20. Comparison of methods for analysis of selective genotyping survival data

    Directory of Open Access Journals (Sweden)

    Dekkers Jack CM

    2006-11-01

    Full Text Available Abstract Survival traits and selective genotyping datasets are typically not normally distributed, thus common models used to identify QTL may not be statistically appropriate for their analysis. The objective of the present study was to compare models for identification of QTL associated with survival traits, in particular when combined with selective genotyping. Data were simulated to model the survival distribution of a population of chickens challenged with Marek disease virus. Cox proportional hazards (CPH, linear regression (LR, and Weibull models were compared for their appropriateness to analyze the data, ability to identify associations of marker alleles with survival, and estimation of effects when all individuals were genotyped (full genotyping and when selective genotyping was used. Little difference in power was found between the CPH and the LR model for low censoring cases for both full and selective genotyping. The simulated data were not transformed to follow a Weibull distribution and, as a result, the Weibull model generally resulted in less power than the other two models and overestimated effects. Effect estimates from LR and CPH were unbiased when all individuals were genotyped, but overestimated when selective genotyping was used. Thus, LR is preferred for analyzing survival data when the amount of censoring is low because of ease of implementation and interpretation. Including phenotypic data of non-genotyped individuals in selective genotyping analysis increased power, but resulted in LR having an inflated false positive rate, and therefore the CPH model is preferred for this scenario, although transformation of the data may also make the Weibull model appropriate for this case. The results from the research presented herein are directly applicable to interval mapping analyses.

  1. Effect of outdoor air pollution on asthma exacerbations in children and adults: Systematic review and multilevel meta-analysis

    Science.gov (United States)

    Quaranta, Nancy; Reynoso, Julieta; Balbi, Brenda; Vasquez, Julia

    2017-01-01

    Background Several observational studies have suggested that outdoor air pollution may induce or aggravate asthma. However, epidemiological results are inconclusive due to the presence of numerous moderators which influence this association. The goal of this study was to assess the relationship between outdoor air pollutants and moderate or severe asthma exacerbations in children and adults through a systematic review and multilevel meta-analysis. Material and methods We searched studies published in English on PubMed, Scopus, and Google Scholar between January 2000 and October 2016. Studies following a case-crossover design with records of emergency departments and/or hospital admissions as a surrogate of moderate or severe asthma exacerbations were selected. A multilevel meta-analysis was employed, taking into account the potential clustering effects within studies examining more than one lag. Odds ratios (ORs) and 95% confidence intervals were estimated. A subgroup analysis in children aged 0 to 18 years and a sensitivity analysis based on the quality of the included studies as defined in the Newcastle-Ottawa Scale were performed. Publication bias was evaluated through visual inspection of funnel plots and by a complementary search of grey literature. (Prospero Registration number CRD42015032323). Results Database searches retrieved 208 records, and finally 22 studies were selected for quantitative analysis. All pollutants except SO2 and PM10 showed a significant association with asthma exacerbations (NO2: 1.024; 95% CI: 1.005,1.043, SO2: 1.039; 95% CI: 0.988,1.094), PM10: 1.024; 95% CI: 0.995,1.053, PM2.5: 1.028; 95% CI: 1.009,1.047, CO: 1.045; 95% CI: 1.005,1.086, O3: 1.032; 95% CI: 1.005,1.060. In children, the association was significant for NO2, SO2 and PM2.5. Conclusion This meta-analysis provides evidence of the association between selected air pollutants and asthma exacerbations for different lags. PMID:28319180

  2. Dysnatremias and Survival in Adult Burn Patients: A Retrospective Analysis

    Science.gov (United States)

    2013-01-11

    DOI: 10.1159/000346206 Dysnatremias and Survival in Adult Burn Patients: A Retrospective Analysis Ian J. Stewart a Benjamin D. Morrow a... mortality rate of 4.3%. On Cox proportional hazard regres- sion age, %TBSA, ISS, and AKIN stage were found to be sig- nificant predictors of mortality ...hypernatremia [1–4] and hyponatremia [1, 4, 5] have been examined in the hospital setting and have been found to be significantly associated with mortality

  3. [Clinical research XXI. From the clinical judgment to survival analysis].

    Science.gov (United States)

    Rivas-Ruiz, Rodolfo; Pérez-Rodríguez, Marcela; Palacios, Lino; Talavera, Juan O

    2014-01-01

    Decision making in health care implies knowledge of the clinical course of the disease. Knowing the course allows us to estimate the likelihood of occurrence of a phenomenon at a given time or its duration. Within the statistical models that allow us to have a summary measure to estimate the time of occurrence of a phenomenon in a given population are the linear regression (the outcome variable is continuous and normally distributed -time to the occurrence of the event-), logistic regression (outcome variable is dichotomous, and it is evaluated at one single interval), and survival curves (outcome event is dichotomous, and it can be evaluated at multiple intervals). The first reference we have of this type of analysis is the work of the astronomer Edmond Halley, an English physicist and mathematician, famous for the calculation of the appearance of the comet orbit, recognized as the first periodic comet (1P/Halley's Comet). Halley also contributed in the area of health to estimate the mortality rate for a Polish population. The survival curve allows us to estimate the probability of an event occurring at different intervals. Also, it leds us to estimate the median survival time of any phenomenon of interest (although the used term is survival, the outcome does not need to be death, it may be the occurrence of any other event).

  4. Travel time to maternity care and its effect on utilization in rural Ghana: a multilevel analysis.

    Science.gov (United States)

    Masters, Samuel H; Burstein, Roy; Amofah, George; Abaogye, Patrick; Kumar, Santosh; Hanlon, Michael

    2013-09-01

    Rates of neonatal and maternal mortality are high in Ghana. In-facility delivery and other maternal services could reduce this burden, yet utilization rates of key maternal services are relatively low, especially in rural areas. We tested a theoretical implication that travel time negatively affects the use of in-facility delivery and other maternal services. Empirically, we used geospatial techniques to estimate travel times between populations and health facilities. To account for uncertainty in Ghana Demographic and Health Survey cluster locations, we adopted a novel approach of treating the location selection as an imputation problem. We estimated a multilevel random-intercept logistic regression model. For rural households, we found that travel time had a significant effect on the likelihood of in-facility delivery and antenatal care visits, holding constant education, wealth, maternal age, facility capacity, female autonomy, and the season of birth. In contrast, a facility's capacity to provide sophisticated maternity care had no detectable effect on utilization. As the Ghanaian health network expands, our results suggest that increasing the availability of basic obstetric services and improving transport infrastructure may be important interventions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. CMT: a constrained multi-level thresholding approach for ChIP-Seq data analysis.

    Directory of Open Access Journals (Sweden)

    Iman Rezaeian

    Full Text Available Genome-wide profiling of DNA-binding proteins using ChIP-Seq has emerged as an alternative to ChIP-chip methods. ChIP-Seq technology offers many advantages over ChIP-chip arrays, including but not limited to less noise, higher resolution, and more coverage. Several algorithms have been developed to take advantage of these abilities and find enriched regions by analyzing ChIP-Seq data. However, the complexity of analyzing various patterns of ChIP-Seq signals still needs the development of new algorithms. Most current algorithms use various heuristics to detect regions accurately. However, despite how many formulations are available, it is still difficult to accurately determine individual peaks corresponding to each binding event. We developed Constrained Multi-level Thresholding (CMT, an algorithm used to detect enriched regions on ChIP-Seq data. CMT employs a constraint-based module that can target regions within a specific range. We show that CMT has higher accuracy in detecting enriched regions (peaks by objectively assessing its performance relative to other previously proposed peak finders. This is shown by testing three algorithms on the well-known FoxA1 Data set, four transcription factors (with a total of six antibodies for Drosophila melanogaster and the H3K4ac antibody dataset.

  6. Effect of Data Model Approach In State Probability Analysis Of Multi-Level Queue Scheduling

    Directory of Open Access Journals (Sweden)

    Diwakar Shukla

    2010-07-01

    Full Text Available In the uniprocessor environment, the number of jobs arriving at the processor of CPU at a time is very large which causes a long waiting queue. When conflict arises due to shared resources or overlap of instructions or logical error, the deadlock state appears where further processing of jobs is blocked completely. While the scheduler jumps from one job to another in order to perform the processing the transition mechanism appears. This paper presents a general structure of transition scenario for the functioning of CPU scheduler in the presence of deadlock condition in setup of multilevel queue scheduling. A data model based Markov chain model is proposed to study the transition phenomenon and a general class of scheduling scheme is designed. Some specific and well known schemes are treated as its particular cases and are compared under the setup of model through a proposed deadlock-waiting index measure. Simulation study is performed to evaluate the comparative merits of specific schemes belonging to the class designed with the help of varying values of α and d.

  7. Are coaches' health promotion activities beneficial for sport participants? A multilevel analysis.

    Science.gov (United States)

    Van Hoye, Aurélie; Heuzé, Jean-Philippe; Van den Broucke, Stephan; Sarrazin, Philippe

    2016-12-01

    As major actors in sports activities, sports coaches can play a significant role in health education and contribute to the psychological well-being of young people. However, not all participants in sports activities experience sports positively, which reduces the potential benefits for health. The present study investigates if coaches' efforts to promote health increase young athletes' enjoyment, self-esteem and perceived health in daily life and decrease sport dropout. To control for the variability between teams and between clubs, multilevel modeling was applied. A sample of 342 young football players completed questionnaires assessing their perceptions of coaches' Health Promotion (HP) activities, enjoyment of sports, dropout intentions, self-esteem and perceived health in daily life. HP general score was positively related to enjoyment and perceived health as well as negatively dropout intentions. Players perceiving their coaches as promoting fair and play (Respect for oneself and others) scored higher on their perceptions of enjoyment in sport, self-esteem and self-reported health, and lower on dropout intentions. Moreover, players recognizing their coaches as encouraging their healthy lifestyle also reported higher perceptions of sport enjoyment, whereas player's perceived coaches' activities on substance use were associated with lower participants' enjoyment. These results support the importance of developing HP in sports clubs. Especially, promoting respect of oneself and others seems to be the more beneficial to sport participants. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  8. Small groups, contexts, and civic engagement: A multilevel analysis of United States Congregational Life Survey data.

    Science.gov (United States)

    Whitehead, Andrew L; Stroope, Samuel

    2015-07-01

    Prior research suggests that church-goers are more civically engaged than their non-church-going counterparts. Little is known, however, about how the popular phenomenon of small groups factors into this equation. In the present study, we examine relationships between small group participation at individual and congregation levels and civic engagement. Using multilevel modeling and national data on congregations and individuals from the U.S. Congregational Life Study (n=82,044), we find that: (1) individual-level small group involvement is associated with four measures of civic engagement; (2) congregation-level small group participation is associated with both lower and higher civic engagement in the case of two outcomes; and (3) in the case of three civic outcomes, congregation-level small group participation moderates individual-level small group involvement such that small group members' civic activity more closely resembles the lower civic engagement of small group nonparticipants. In the case of one civic outcome, at high levels of overall small group participation, small group members' civic engagement drops below that of small group nonparticipants. Explanations for these findings, including a "crowding out" effect, are examined including their complex implications for debates regarding small groups, religious involvement, and civic engagement.

  9. On the spatial inequalities of institutional versus home births in Ghana: a multilevel analysis.

    Science.gov (United States)

    Johnson, Fiifi Amoako; Padmadas, Sabu S; Brown, James J

    2009-02-01

    Spatial inequalities related to the choice of delivery care have not been studied systematically in Sub-Saharan Africa where maternal and perinatal health outcomes continue to worsen despite a range of safe motherhood interventions. Using retrospective data from the 1998 and 2003 Demographic and Health Surveys, this paper investigates the extent of changes in spatial inequalities associated with type of delivery care in Ghana with a focus on rural-urban differentials within and across the three ecological zones (Savannah, Forest and Coastal). More than one-half of births in Ghana continue to occur outside health institutions without any skilled obstetric care. While this is already known, we present evidence from multilevel analyses that there exist considerable and growing inequalities, with regard to birth settings between communities, within rural and urban areas and across the ecological zones. The results show evidence of poor and disproportionate use of institutional care at birth; the inequalities remained high and unchanged in both urban and rural communities within the Savannah zone and widening in urban communities of the Forest and Coastal zones. The key policy challenges in Ghana, therefore, include both increasing the uptake of institutional delivery care and ensuring equity in access to both public and private health institutions.

  10. Factors associated with use of community mental health services by schizophrenia patients using multilevel analysis

    Directory of Open Access Journals (Sweden)

    Moreno Patricia

    2011-10-01

    Full Text Available Abstract Background Persons with schizophrenia and related disorders may be particularly sensitive to a number of determinants of service use, including those related with illness, socio-demographic characteristics and organizational factors. The objective of this study is to identify factors associated with outpatient contacts at community mental health services of patients with schizophrenia or related disorders. Methods This cross-sectional study analyzed 1097 patients. The main outcome measure was the total number of outpatient consultations during one year. Independent variables were related to socio-demographic, clinical and use of service factors. Data were collected from clinical records. Results The multilevel linear regression model explained 46.35% of the variance. Patients with significantly more contacts with ambulatory services were not working and were receiving welfare benefits (p = 0.02, had no formal education (p = 0.02, had a global level of severity of two or three (four being the most severe (p Conclusions As expected, the variables that explained the use of community service could be viewed as proxies for severity of illness. The most surprising finding, however, was that a group of four psychiatrists was also independently associated with use of ambulatory services by patients with schizophrenia or related disorders. More research is needed to carefully examine how professional support networks interact to affect use of mental health.

  11. Political regimes, political ideology, and self-rated health in Europe: a multilevel analysis.

    Science.gov (United States)

    Huijts, Tim; Perkins, Jessica M; Subramanian, S V

    2010-07-22

    Studies on political ideology and health have found associations between individual ideology and health as well as between ecological measures of political ideology and health. Individual ideology and aggregate measures such as political regimes, however, were never examined simultaneously. Using adjusted logistic multilevel models to analyze data on individuals from 29 European countries and Israel, we found that individual ideology and political regime are independently associated with self-rated health. Individuals with rightwing ideologies report better health than leftwing individuals. Respondents from Eastern Europe and former Soviet republics report poorer health than individuals from social democratic, liberal, Christian conservative, and former Mediterranean dictatorship countries. In contrast to individual ideology and political regimes, country level aggregations of individual ideology are not related to reporting poor health. This study shows that although both individual political ideology and contextual political regime are independently associated with individuals' self-rated health, individual political ideology appears to be more strongly associated with self-rated health than political regime.

  12. Social capital and adolescent smoking in schools and communities: a cross-classified multilevel analysis.

    Science.gov (United States)

    De Clercq, Bart; Pfoertner, Timo-Kolja; Elgar, Frank J; Hublet, Anne; Maes, Lea

    2014-10-01

    We sought to determine whether social capital at the individual-, school- and community-level can explain variance in adolescent smoking and accounts for social inequalities in smoking. We collected data as part of the 2005/6 Health Behavior in School-aged Children survey, a nationally representative survey of the health and well-being of high school pupils in Belgium (Flanders). Social capital was assessed by structural and cognitive components of family social capital, a four-factor school social capital scale and a cognitive community social capital scale. We fitted non-hierarchical multilevel models to the data, with 8453 adolescents nested within a cross-classification of 167 schools and 570 communities. Significant variation in adolescent regular smoking was found between schools, but not between communities. Only structural family social capital and cognitive school social capital variables negatively related to regular smoking. No interactions between socio-economic status and social capital variables were found. Our findings suggest that previously observed community-level associations with adolescent smoking may be a consequence of unmeasured confounding. Distinguishing nested contexts of social capital is important because their associations with smoking differ.

  13. Both trait and state mindfulness predict lower aggressiveness via anger rumination: A multilevel mediation analysis.

    Science.gov (United States)

    Eisenlohr-Moul, Tory A; Peters, Jessica R; Pond, Richard S; DeWall, C Nathan

    2016-06-01

    Trait mindfulness, or the capacity for nonjudgmental, present-centered attention, predicts lower aggression in cross-sectional samples, an effect mediated by reduced anger rumination. Experimental work also implicates state mindfulness (i.e., fluctuations around one's typical mindfulness) in aggression. Despite evidence that both trait and state mindfulness predict lower aggression, their relative impact and their mechanisms remain unclear. Higher trait mindfulness and state increases in mindfulness facets may reduce aggression-related outcomes by (1) limiting the intensity of anger, or (2) limiting rumination on anger experiences. The present study tests two hypotheses: First, that both trait and state mindfulness contribute unique variance to lower aggressiveness, and second, that the impact of both trait and state mindfulness on aggressiveness will be uniquely partially mediated by both anger intensity and anger rumination. 86 participants completed trait measures of mindfulness, anger intensity, and anger rumination, then completed diaries for 35 days assessing mindfulness, anger intensity, anger rumination, anger expression, and self-reported and behavioral aggressiveness. Using multilevel zero-inflated regression, we examined unique contributions of trait and state mindfulness facets to daily anger expression and aggressiveness. We also examined the mediating roles of anger intensity and anger rumination at both trait and state levels. Mindfulness facets predicted anger expression and aggressiveness indirectly through anger rumination after controlling for indirect pathways through anger intensity. Individuals with high or fluctuating aggression may benefit from mindfulness training to reduce both intensity of and rumination on anger.

  14. Parental relationship satisfaction in families of children with autism spectrum disorder (ASD): A multilevel analysis.

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    Langley, Emma; Totsika, Vasiliki; Hastings, Richard P

    2017-07-01

    Caring for a child with Autism Spectrum Disorder (ASD) has been linked to a range of negative outcomes for parents but less is known about the putative impact upon the parental couple relationship. The relationship satisfaction of parents of children with ASD was investigated using multilevel modeling. Mothers and fathers (146 couples) reported on their relationship satisfaction, their own well-being, and the behavior problems of the child with ASD and a sibling. Results indicated that mothers and fathers reported similar levels of relationship satisfaction and it was significantly and negatively associated with parental depression and the behavior problems of the child with ASD. Relationship satisfaction was unrelated to the behavior problems of a sibling, the number of children in the household, and family socioeconomic position (SEP). Further longitudinal research that captures a broader range of variables is required to build a theoretical understanding of relationship satisfaction in families of children with ASD. Current evidence suggests that early intervention routes targeting either child behavior problems, parental mental health, or the couple relationship have the potential to benefit inter-connected subsystems within the broader family system. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1259-1268. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

  15. Democracy and self-rated health across 67 countries: A multilevel analysis.

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    Krueger, Patrick M; Dovel, Kathryn; Denney, Justin T

    2015-10-01

    Existing research has found a positive association between countries' level of democratic governance and the health of their populations, although that research is limited by the use of data from small numbers of high-income countries or aggregate data that do not assess individual-level health outcomes. We extend prior research by using multilevel World Health Survey (2002-2004) data on 313,554 individuals in 67 countries, and find that the positive association between democratic governance and self-rated health persists after adjusting for both individual- and country-level confounders. However, the mechanisms linking democracy and self-rated health remain unclear. Individual-level measures of socioeconomic status, and country-level measures of economic inequality and investments in public health and education, do not significantly mediate the association between democratic governance and self-rated health. The persistent association between democratic governance and health suggests that the political organization of societies may be an important upstream determinant of population health.

  16. Geographic and Individual Differences in Healthcare Access for U.S. Transgender Adults: A Multilevel Analysis.

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    White Hughto, Jaclyn M; Murchison, Gabriel R; Clark, Kirsty; Pachankis, John E; Reisner, Sari L

    2016-12-01

    To identify geographic and individual-level factors associated with healthcare access among transgender people in the United States. Multilevel analyses were conducted to investigate lifetime healthcare refusal using national data from 5831 U.S. transgender adults. Hierarchical generalized linear models examined associations between individual (age, gender, race, income, insurance, and healthcare avoidance) and state-level factors (percent voting Republican, percent same-sex couple households, income inequality, and transgender protective laws) and lifetime refusal of care. Results show that individual-level factors (being older; trans feminine; Native American, multiracial, or other racial/ethnic minority; having low income; and avoiding care due to discrimination) are positively associated with care refusal (all P-values <0.05). Adjusting for individual-level factors, variation was observed across U.S. states, with a greater proportion of states in the Southern and Western United States with transgender residents at increased odds of experiencing care refusal, relative to other regions of the United States. When adjusting for state-level factors, the percentage of the state population voting Republican was positively associated with care refusal among the transgender adults sampled (P < 0.01). Transgender adults surveyed reported differential access to healthcare by geographic region. Identifying geographic and individual-level factors associated with healthcare barriers allows for the development of targeted educational and policy interventions to improve healthcare access for transgender people most in need of services.

  17. Contextual socioeconomic determinants of cardiovascular risk factors in rural south-west China: a multilevel analysis

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    Geater Alan

    2007-05-01

    Full Text Available Abstract Background We examined independent influences of contextual variables on cardiovascular risk factors in Shilin county, Yunnan province, South-west China. Methods Three villages were selected from each of the ten townships based on probability proportional to size. In each selected village, 200 individuals aged ≥ 45 years were chosen based on simple random sampling method. From 6006 individuals, information on demographic characteristics, smoking and drinking status was obtained by interview. Blood pressure, height, weight, and waist and hip girth were measured. Fasting blood sugar was measured in a 10-percent subsample. Contextual data were from official reports. Multi-level regression modelling with adjustment for individual and contextual variables was used. Results Contextual variables associated with CVD risk factors included: remoteness of village with higher blood pressure and fasting blood sugar, high proportion of Yi minority with drinking, high literacy rate with a lower rate of smoking and a lower mean waist-hip ratio, and high average income with lower systolic blood pressure and body mass index (BMI but higher FBS. Conclusion While contextual SES is associated with a few CVD risk factors, villages with high level of income are worse off in fasting blood sugar. Strategies of economic development should be reviewed to avoid adverse effects on health.

  18. Community Influences on Married Women's Safer Sex Negotiation Attitudes in Bangladesh: A Multilevel Analysis.

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    Jesmin, Syeda S; Cready, Cynthia M

    2016-02-01

    The influence of disadvantaged or deprived community on individuals' health risk-behaviors is increasingly being documented in a growing body of literature. However, little is known about the effects of community characteristics on women's sexual attitudes and behaviors. To examine community effects on married women's safer sex negotiation attitudes, we analyzed cross-sectional data from the 2011 Bangladesh Demographic and Health Surveys on a sample of 15,134 married women in 600 communities. We estimated two multilevel logistic regression models. Model 1, which included only individual-level variables, showed that women's autonomy/empowerment, age, and HIV knowledge had significant associations with their safer sex negotiation attitudes. We did not find any socioeconomic status gradient in safer sex negotiation attitudes at the individual level. Adding community-level variables in Model 2 significantly improved the fit of the model. Strikingly, we found that higher community-level poverty was associated with greater positive safer sex negotiation attitudes. Prevailing gender norms and overall women's empowerment in the community also had significant effects. While research on community influences calls for focusing on disadvantaged communities, our research highlights the importance of not underestimating the challenges that married women in economically privileged communities may face in negotiating safer sex. To have sufficient and equitable impact on married women's sexual and reproductive health, sexual and reproductive health promotion policies and programs need to be directed to women in wealthier communities as well.

  19. Political regimes, political ideology, and self-rated health in Europe: a multilevel analysis.

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    Tim Huijts

    Full Text Available BACKGROUND: Studies on political ideology and health have found associations between individual ideology and health as well as between ecological measures of political ideology and health. Individual ideology and aggregate measures such as political regimes, however, were never examined simultaneously. METHODOLOGY/PRINCIPAL FINDINGS: Using adjusted logistic multilevel models to analyze data on individuals from 29 European countries and Israel, we found that individual ideology and political regime are independently associated with self-rated health. Individuals with rightwing ideologies report better health than leftwing individuals. Respondents from Eastern Europe and former Soviet republics report poorer health than individuals from social democratic, liberal, Christian conservative, and former Mediterranean dictatorship countries. In contrast to individual ideology and political regimes, country level aggregations of individual ideology are not related to reporting poor health. CONCLUSIONS/SIGNIFICANCE: This study shows that although both individual political ideology and contextual political regime are independently associated with individuals' self-rated health, individual political ideology appears to be more strongly associated with self-rated health than political regime.

  20. Coopetition in health care: A multi-level analysis of its individual and organizational determinants.

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    Westra, Daan; Angeli, Federica; Carree, Martin; Ruwaard, Dirk

    2017-08-01

    Cooperative inter-organizational relations are salient to healthcare delivery. However, they do not match with the pro-competitive healthcare reforms implemented in several countries. Healthcare organizations thus need to balance competition and cooperation in a situation of 'coopetition'. In this paper we study the individual and organizational determinants of coopetition versus those of cooperation in the price-competitive specialized care sector of the Netherlands. We use shared medical specialists as a proxy of collaboration between healthcare organizations. Based on a sample of 15,431 medical specialists and 371 specialized care organizations from March 2016, one logistic multi-level model is used to predict medical specialists' likelihood to be shared and another to predict their likelihood to be shared to a competitor. We find that different organizations share different specialists to competitors and non-competitors. Cooperation and coopetition are hence distinct organizational strategies in health care. Cooperation manifests through spin-off formation. Coopetition occurs most among organizations in the price-competitive market segment but in alternative geographical markets. Hence, coopetition in health care does not appear to be particularly anti-competitive. However, healthcare organizations seem reluctant to share their most specialized human resources, limiting the knowledge-sharing effects of this type of relation. Therefore, it remains unclear whether coopetition in health care is beneficial to patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evaluating disease management program effectiveness: an introduction to survival analysis.

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    Linden, Ariel; Adams, John L; Roberts, Nancy

    2004-01-01

    Currently, the most widely used method in the disease management industry for evaluating program effectiveness is the "total population approach." This model is a pretest-posttest design, with the most basic limitation being that without a control group, there may be sources of bias and/or competing extraneous confounding factors that offer plausible rationale explaining the change from baseline. Survival analysis allows for the inclusion of data from censored cases, those subjects who either "survived" the program without experiencing the event (e.g., achievement of target clinical levels, hospitalization) or left the program prematurely, due to disenrollement from the health plan or program, or were lost to follow-up. Additionally, independent variables may be included in the model to help explain the variability in the outcome measure. In order to maximize the potential of this statistical method, validity of the model and research design must be assured. This paper reviews survival analysis as an alternative, and more appropriate, approach to evaluating DM program effectiveness than the current total population approach.

  2. Multi-focus and multi-level techniques for visualization and analysis of networks with thematic data

    Science.gov (United States)

    Cossalter, Michele; Mengshoel, Ole J.; Selker, Ted

    2013-01-01

    Information-rich data sets bring several challenges in the areas of visualization and analysis, even when associated with node-link network visualizations. This paper presents an integration of multi-focus and multi-level techniques that enable interactive, multi-step comparisons in node-link networks. We describe NetEx, a visualization tool that enables users to simultaneously explore different parts of a network and its thematic data, such as time series or conditional probability tables. NetEx, implemented as a Cytoscape plug-in, has been applied to the analysis of electrical power networks, Bayesian networks, and the Enron e-mail repository. In this paper we briefly discuss visualization and analysis of the Enron social network, but focus on data from an electrical power network. Specifically, we demonstrate how NetEx supports the analytical task of electrical power system fault diagnosis. Results from a user study with 25 subjects suggest that NetEx enables more accurate isolation of complex faults compared to an especially designed software tool.

  3. Geographic information system and multilevel analysis: gingival status among 12-year-old schoolchildren in São Paulo, Brazil.

    Science.gov (United States)

    Pereira, Stela Márcia; Pardi, Vanessa; Cortellazzi, Karine L; Ambrosano, Glaucia Maria Bovi; Vettorazzi, Carlos Alberto; Ferraz, Sílvio F B; Meneghim, Marcelo de Castro; Pereira, Antonio Carlos

    2014-02-01

    To evaluate gingival and calculus status among schoolchildren 12 years of age using a geographic information system and multilevel analysis. A total of 1 002 schoolchildren were selected from 18 municipal districts by means of cluster sampling, from among 25 public and private schools in Piracicaba, São Paulo, Brazil, in 2005. Examinations were carried out by a single calibrated examiner utilizing the criteria of the World Health Organization, as well as the Community Periodontal Index. Social, economic, and behavioral variables were recorded with the use of a questionnaire and were used in the individual analysis (first level). The variables "percentage of heads of families without income" and "percentage of illiterate heads of families" were used in the contextual analysis (second level). A geographic information system was constructed for mapping the distribution of gingival bleeding. The variables were visually distinguished in the maps and demonstrated a tendency toward better gingival health in the central areas of the city, which are recognized as more privileged. On the contextual level, only the "percentage of illiterate heads of families" was significantly associated to gingival bleeding. The study confirms better oral health status among schoolchildren from privileged families, but does not confirm the data regarding "income." The individuals from areas in which the heads of family did not have income were not associated to a higher prevalence of gingival problems. This suggests that these individuals are reasonably protected from the impact of social privation due to the actions of public health care services in the municipality.

  4. Multi-level analysis of electronic health record adoption by health care professionals: A study protocol

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    Labrecque Michel

    2010-04-01

    Full Text Available Abstract Background The electronic health record (EHR is an important application of information and communication technologies to the healthcare sector. EHR implementation is expected to produce benefits for patients, professionals, organisations, and the population as a whole. These benefits cannot be achieved without the adoption of EHR by healthcare professionals. Nevertheless, the influence of individual and organisational factors in determining EHR adoption is still unclear. This study aims to assess the unique contribution of individual and organisational factors on EHR adoption in healthcare settings, as well as possible interrelations between these factors. Methods A prospective study will be conducted. A stratified random sampling method will be used to select 50 healthcare organisations in the Quebec City Health Region (Canada. At the individual level, a sample of 15 to 30 health professionals will be chosen within each organisation depending on its size. A semi-structured questionnaire will be administered to two key informants in each organisation to collect organisational data. A composite adoption score of EHR adoption will be developed based on a Delphi process and will be used as the outcome variable. Twelve to eighteen months after the first contact, depending on the pace of EHR implementation, key informants and clinicians will be contacted once again to monitor the evolution of EHR adoption. A multilevel regression model will be applied to identify the organisational and individual determinants of EHR adoption in clinical settings. Alternative analytical models would be applied if necessary. Results The study will assess the contribution of organisational and individual factors, as well as their interactions, to the implementation of EHR in clinical settings. Conclusions These results will be very relevant for decision makers and managers who are facing the challenge of implementing EHR in the healthcare system. In addition

  5. Individual and Regional Determinants for Physical Therapy Utilization in Germany: Multilevel Analysis of National Survey Data.

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    Rommel, Alexander; Kroll, Lars Eric

    2017-05-01

    Physical therapy is included in many clinical guidelines and is a commonly used health service. However, access to its benefits should not strongly depend on social or demographic factors. The present study used the Andersen model to explain to what extent physical therapy utilization in Germany depends on factors beyond medical need. The German Health Interview and Examination Survey for Adults (DEGS, 2008-2011; target population, 18-79 years) is part of the German health-monitoring system. Two-stage stratified cluster sampling resulted in a sample of 8152 participants. Data were matched with district-related information on social structures and service supply. Following Andersen's Behavioral Model of Health Services Use, this study identified predisposing, enabling, and need factors for physical therapy utilization using multilevel logistic regression analyses. Physical therapy was used by 23.4% (95% CI: 22.0-24.8) of the German population within one year, with a higher proportion of females (26.8%; 95% CI: 25.1-28.6) than males (19.9%; 95% CI: 18.1-21.8) and an increase with age. Beyond medical need, physical therapy utilization depended on higher education, migrant background, nonsmoking (predisposing), social support, higher income, private health insurance, and gatekeeping service contact (enabling). Variation among districts partly reflected regional supply. Because the present study was cross-sectional, its findings provide representative information on physical therapy use but do not establish final causal links or identify whether utilization or supply in certain districts or population groups is adequate. Whether certain regions are under- or overserved and whether further regulations are needed is of political interest. Physicians and therapists should develop strategies to improve both adherence of hard-to-reach groups and supply in low-supply regions.

  6. Analysis of Economic Determinants of Fertility in Iran: A Multilevel Approach

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    Maryam Moeeni

    2014-08-01

    Full Text Available Background During the last three decades, the Total Fertility Rate (TFR in Iran has fallen considerably; from 6.5 per woman in 1983 to 1.89 in 2010. This paper analyzes the extent to which economic determinants at the micro and macro levels are associated with the number of children in Iranian households. Methods Household data from the 2010 Household Expenditure and Income Survey (HEIS is linked to provincial data from the 2010 Iran Multiple-Indicator Demographic and Health Survey (IrMIDHS, the National Census of Population and Housing conducted in 1986, 1996, 2006 and 2011, and the 1985–2010 Iran statistical year books. Fertility is measured as the number of children in each household. A random intercept multilevel Poisson regression function is specified based on a collective model of intra-household bargaining power to investigate potential determinants of the number of children in Iranian households. Results Ceteris paribus (other things being equal, probability of having more children drops significantly as either real per capita educational expenditure or real total expenditure of each household increase. Both the low- and the high-income households show probabilities of having more children compared to the middle-income households. Living in provinces with either higher average amount of value added of manufacturing establishments or lower average rate of house rent is associated to higher probability of having larger number of children. Higher levels of gender gap indices, resulting in household’s wife’s limited power over household decision-making, positively affect the probability of having more children. Conclusion Economic determinants at the micro and macro levels, distribution of intra-household bargaining power between spouses and demographic covariates determined fertility behavior of Iranian households.

  7. Predicting post-traumatic stress disorder treatment response in refugees: Multilevel analysis.

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    Haagen, Joris F G; Ter Heide, F Jackie June; Mooren, Trudy M; Knipscheer, Jeroen W; Kleber, Rolf J

    2017-03-01

    Given the recent peak in refugee numbers and refugees' high odds of developing post-traumatic stress disorder (PTSD), finding ways to alleviate PTSD in refugees is of vital importance. However, there are major differences in PTSD treatment response between refugees, the determinants of which are largely unknown. This study aimed at improving PTSD treatment for adult refugees by identifying PTSD treatment response predictors. A prospective longitudinal multilevel modelling design was used to predict PTSD severity scores over time. We analysed data from a randomized controlled trial with pre-, post-, and follow-up measurements of the safety and efficacy of eye movement desensitization and reprocessing and stabilization in asylum seekers and refugees suffering from PTSD. Lack of refugee status, comorbid depression, demographic, trauma-related and treatment-related variables were analysed as potential predictors of PTSD treatment outcome. Treatment outcome data from 72 participants were used. The presence (B = 6.5, p = .03) and severity (B = 6.3, p Refugee patients who suffer from PTSD and severe comorbid depression benefit less from treatment aimed at alleviating PTSD. Results highlight the need for treatment adaptations for PTSD and comorbid severe depression in traumatized refugees, including testing whether initial targeting of severe depressive symptoms increases PTSD treatment effectiveness. There are differences in post-traumatic stress disorder (PTSD) treatment response between traumatized refugees. Comorbid depressive disorder and depression severity predict poor PTSD response. Refugees with PTSD and severe depression may not benefit from PTSD treatment. Targeting comorbid severe depression before PTSD treatment is warranted. This study did not correct for multiple hypothesis testing. Comorbid depression may differentially impact alternative PTSD treatments. © 2016 The British Psychological Society.

  8. Is the "Glasgow effect" of cigarette smoking explained by socio-economic status?: A multilevel analysis

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    Leyland Alastair H

    2009-07-01

    Full Text Available Abstract Background The Glasgow area has elevated levels of deprivation and is known for its poor health and associated negative health-related behaviours, which are socially patterned. Of interest is whether high smoking rates are explained by the area's socio-economic profile. Methods Data on age, sex, current/previous smoking status, area deprivation, social class, education, economic activity, postcode sector, and health board region were available from Scottish Health Surveys conducted in 1995, 1998 and 2003. Multilevel logistic regression models were applied by sex, unadjusted and adjusted for age, survey year, and socio-economic factors, accounting for geographical hierarchy and missing data. Results Compared with the rest of Scotland, men living in Greater Glasgow were 30% and women 43% more likely to smoke [odds ratio (OR = 1.30, (95% CI = 1.08–1.56 and (OR = 1.43, CI = 1.22–1.68, respectively] before adjustment. In adjusted results, the association between living in Greater Glasgow and current smoking was attenuated [OR = 0.92, CI = 0.78–1.09 for men, and OR = 1.08, CI = 0.94–1.23 for women; results based on multiply imputed data to account for missing values remained borderline significant for women]. Accounting for individuals who had been told to give up smoking by a medical person/excluding ex-smokers did not alter results. Conclusion High levels of smoking in Greater Glasgow were attributable to its poorer socio-economic position and the strong social patterning of smoking. Tackling Glasgow's, and indeed Scotland's, poor health must involve policies to alleviate problems associated with poverty.

  9. Italian deprivation index and dental caries in 12-year-old children: a multilevel Bayesian analysis.

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    Matranga, Domenica; Campus, Guglielmo; Castiglia, Paolo; Strohmenger, Laura; Solinas, Giuliana

    2014-01-01

    Evidence from the literature has shown that people with a lower socioeconomic status enjoy less good health than people with a higher socioeconomic status. The Italian deprivation index (DI) was used with the aim to evaluate the association between the DMFT index and risk factors for dental caries, including city population and DI. The study included 4,305 12-year-old children living in 38 cities classified by demographic size as small, midsize and large. Zero-inflated negative binomial multilevel regression models were used to assess risk factors for DMFT and to address excess of zero DMFT and overdispersion through a Bayesian approach. The difference in the average level of DMFT among children living in cities with different DI quintile was not statistically significant (p = 0.578). The DI and ln(population), included as city-level fixed effects in the two-level variance components model, were not statistically significant. Consuming sweet drinks on average increased the mean DMFT of a susceptible child, while having a highly educated mother reduced it. Unobserved heterogeneity among cities was detected for the probability to be non-susceptible to caries (city-level variance = 0.26 with 95% credibility interval 0.09-0.57), while no territorial effect was found for the mean DMFT of the susceptible children. Our results suggest that the DI and city population did not play a role in explaining between-city variability. Interventions against social deprivation can be influential on the perception of oral health in Italian 12-year-old children to the extent that they can also affect individual level factors.

  10. Adolescent substance use and peer use: a multilevel analysis of cross-sectional population data.

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    Kristjansson, Alfgeir Logi; Sigfusdottir, Inga Dora; Allegrante, John P

    2013-07-31

    Limited evidence exists concerning the importance of social contexts in adolescent substance use prevention. In addition to the important role schools play in educating young people, they are important ecological platforms for adolescent health, development and behaviors. In this light, school community contexts represent an important, but largely neglected, area of research in adolescent substance use and prevention, particularly with regard to peer influences. This study sought to add to a growing body of literature into peer contexts by testing a model of peer substance use simultaneously on individual and school community levels while taking account of several well established individual level factors. We analyzed population-based data from the 2009 Youth in Iceland school survey, with 7,084 participants (response rate of 83.5%) nested within 140 schools across Iceland. Multilevel logistic regression models were used to analyze the data. School-level peer smoking and drunkenness were positively related to adolescent daily smoking and lifetime drunkenness after taking account of individual level peer smoking and drunkenness. These relationships held true for all respondents, irrespective of socio-economic status and other background variables, time spent with parents, academic performance, self-assessed peer respect for smoking and alcohol use, or if they have substance-using friends or not. On the other hand, the same relationships were not found with regard to individual and peer cannabis use. The school-level findings in this study represent context effects that are over and above individual-level associations. This holds although we accounted for a large number of individual level variables that studies generally have not included. For the purpose of prevention, school communities should be targeted as a whole in substance use prevention programs in addition to reaching to individuals of particular concern.

  11. Perceptions of neighborhood safety and asthma among children and adolescents in Los Angeles: a multilevel analysis.

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    Marlene Camacho-Rivera

    Full Text Available BACKGROUND: Research examining the impact of neighborhoods on asthma has shown an increased interest in the role of the psychosocial environment. We examined the associations between various measures of neighborhood safety, individual and family characteristics, and asthma outcomes among children in Los Angeles. METHODS: Multilevel logistic regression models were used to analyze data on 3,114 children across 65 neighborhoods from Wave 1 of the Los Angeles Family and Neighborhood Survey (2000 to 2002. Primary caregivers reported asthma outcome and all individual covariates; home environmental characteristics were observed by the interviewer. RESULTS: In fully adjusted models, parents who reported their neighborhood fairly safe or somewhat dangerous had lower odds of reported lifetime asthma compared to those who reported their neighborhood completely safe (OR 0.71; 95% CI 0.52-0.96 and OR 0.60; 95% CI 0.42-0.88 respectively. Conversely, parents who reported they could not trust their neighbors to keep their children safe had a nearly 40% increase in lifetime asthma compared to those who reported they could trust their neighbors to keep their children safe (OR 1.39; 95% CI 1.07-1.81. CONCLUSIONS: The study demonstrates a complex pattern between various measures of neighborhood safety and asthma and suggests that these relationships may operate differently in Los Angeles. As an increasing proportion of children are growing up in newer Western and Southwestern cities, which have different physical layouts and residential segregation patterns compared to Northeast and Midwestern cities, future studies should continue to examine neighborhood psychosocial stressors and asthma in diverse contexts.

  12. Patient and organisational variables associated with pressure ulcer prevalence in hospital settings: a multilevel analysis.

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    Bredesen, Ida Marie; Bjøro, Karen; Gunningberg, Lena; Hofoss, Dag

    2015-08-27

    To investigate the association of ward-level differences in the odds of hospital-acquired pressure ulcers (HAPUs) with selected ward organisational variables and patient risk factors. Multilevel approach to data from 2 cross-sectional studies. 4 hospitals in Norway were studied. 1056 patients at 84 somatic wards. HAPU. Significant variance in the odds of HAPUs was found across wards. A regression model using only organisational variables left a significant variance in the odds of HAPUs across wards but patient variables eliminated the across-ward variance. In the model including organisational and patient variables, significant ward-level HAPU variables were ward type (rehabilitation vs surgery/internal medicine: OR 0.17 (95% CI 0.04 to 0.66)), use of preventive measures (yes vs no: OR 2.02 (95% CI 1.12 to 3.64)) and ward patient safety culture (OR 0.97 (95% CI 0.96 to 0.99)). Significant patient-level predictors were age >70 vs variables entered the explanatory model, indicates that the HAPU problem may be reduced by ward-level organisation of care improvements, that is, by improving the patient safety culture and implementation of preventive measures. Some wards may prevent pressure ulcers better than other wards. The fact that ward-level variation was eliminated when patient-level HAPU variables were included in the model indicates that even wards with the best HAPU prevention will be challenged by an influx of high-risk patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  13. Income, financial barriers to health care and public health expenditure: A multilevel analysis of 28 countries.

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    Kim, Tae Jun; Vonneilich, Nico; Lüdecke, Daniel; von dem Knesebeck, Olaf

    2017-03-01

    International studies have repeatedly shown that people with lower income are more likely to experience difficulties to access medical services. Less is known on why these relations vary across countries. This study investigates whether the association between income and financial barriers to health care is influenced by national public health expenditures (PHE, in % of total health expenditure). Data from the International Social Survey Programme (2011) was used (28 countries, 23,669 respondents). Financial barriers were assessed by the individual experience of forgone care due to financial reasons. Monthly equivalent household income was included as the main predictor. Other individual-level control variables were age, gender, education, subjective health, insurance coverage and place of living. PHE was considered as a macro-level predictor, adjusted for total health expenditure. Statistically significant associations between income and forgone care were found in 21 of 28 examined countries. Multilevel analyses across countries revealed that people with lower income have a higher likelihood to forgo needed medical care (OR: 3.94, 95%-CI: 2.96-5.24). After adjustments for individual-level covariates, this association slightly decreased (OR: 2.94, 95%-CI: 2.16-3.99). PHE did not moderate the relation between income and forgone care. The linkage between health system financing and inequalities in access to health care seems to be more complex than initially assumed, pointing towards further research to explore how PHE affects the redistribution of health resources in different health care systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Analysis of the role of General Practice in preventing Avoidable Hospitalisation through a multilevel approach

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    Aldo Rosano

    2016-06-01

    Full Text Available Objective. To examine the relationship between Avoidable Hospitalisation (AH and the activities of General Practitioners (GPs. The study was carried out in the Lazio Region (Italy within different organizational models of primary care (PC delivery. Methods: Secondary data of a set of GP activities delivered to the Lazio population as listed in the Lazio GPs in 2008, were used. For each GP a set of health services delivered to the patients on their practice lists were measured. The relation between the rates of AH, acute and chronic conditions separately, and the rates of such health services were analyzed through the use of a multilevel Poisson regression model, adjusted according to patients’ health status. Results: The study included data from all the active GPs (4,837 in the Lazio Region and their 4,666,037 registered patients. The overall AH rate of the registered patients was 7.7 per 1,000, 2.2 for acute and 5.5 for chronic conditions. The diagnostics prescription by GPs is associated with a 7% (IRR=0.93;95% C.I.:0.89-0.97 reduction of the chronic AH rate. Patients registered at GPs working within a team practice resulted in a hospitalisation rate decrease of 5% (IRR= 0.95; 95% C.I.:0.91-0.99  for avoidable acute conditions. Conclusion: The study showed that the role of GPs in preventing AH is substantial, particularly when team practice is performed and specifically when additional diagnostics are prescribed. The study is further evidence in favor of the validity of AH as an outcome measure of quality and accessibility of primary care.

  15. Survival Analysis of Drug Abuse Relapse in Addiction Treatment Centers

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    Kassani

    2015-09-01

    Full Text Available Background Drug abuse is a chronic and enduring phenomenon, which is among the important challenging public health problems. One of the main aspects in drug abuse is the relapse. Objectives The aims of this study were to estimate the time to relapse (survival rate and to evaluate some of its associated variables by survival analysis. Patients and Methods This research was conducted in four addiction treatment centers on 140 self-referred addicts in Ilam city, Iran, in 2012. Cluster sampling method was used for selecting the samples and data were collected by interview and referring to the subjects’ records. The gathered data were analyzed through the life table, Kaplan-Meier analysis, log rank test, and Cox regression. Results The relapse rate was 30.42%, mean and median of the time to relapse (survival time were 27.40 ± 1.63 months (CI 95%: 24.19 - 30.60 and 25 ± 2.25 months (CI 95%: 22.5 - 27.5, respectively. In the first six months, the cumulative survival rate was 83%, while in the 24th month it was 46% and the following time was consistent. Job status (OR = 2.64, marital status (OR = 1.55, family size (OR = 1.20 and age (OR = 0.23 were statistically significant in Cox regression model. Conclusions In the initial treatment, it seems necessary to supervise and monitor the treatment process through staff in addiction treatment centers together with the company of the addicts’ families to reduce relapse rate.

  16. Individual and classroom variables associated with relational aggression in elementary-school aged children : A multilevel analysis

    NARCIS (Netherlands)

    Kuppens, S.; Grietens, H.; Onghena, P.; Michiels, D.; Subramanian, S. V.

    2008-01-01

    Relational aggression was studied within classroom environments by examining individual and classroom correlates among 2731 children (3rd-5th graders) during two successive measurement years. Multilevel analyses yielded small gender differences for relational aggression, indicating that such aggress

  17. Individual and classroom variables associated with relational aggression in elementary-school aged children : A multilevel analysis

    NARCIS (Netherlands)

    Kuppens, S.; Grietens, H.; Onghena, P.; Michiels, D.; Subramanian, S. V.

    2008-01-01

    Relational aggression was studied within classroom environments by examining individual and classroom correlates among 2731 children (3rd-5th graders) during two successive measurement years. Multilevel analyses yielded small gender differences for relational aggression, indicating that such aggress

  18. Community characteristics associated with HIV risk among injection drug users in the San Francisco Bay Area: a multilevel analysis.

    Science.gov (United States)

    Bluthenthal, Ricky N; Do, D Phuong; Finch, Brian; Martinez, Alexis; Edlin, Brian R; Kral, Alex H

    2007-09-01

    Community characteristics have been associated with racial and ethnic health disparities for a wide range of ailments and conditions. Previous research has found that rates of AIDS cases among injection drug users (IDUs) vary by community characteristics. However, few studies have examined whether community characteristics are associated with HIV risk behaviors among IDUs. To address this gap in the literature, we examined the associations between census-tract-level community characteristics and injection-related and sex-related HIV risk behaviors among IDUs in the San Francisco Bay Area. Individual HIV risk behaviors were collected from 4,956 IDUs between 1998 and 2002. Using 2000 US census data, we constructed four census-level community measures: percent African American, percent male unemployment, percent of households that receive public assistance, and median household income. All community variables were measured continuously. Multilevel modeling was used to determine if community characteristics were associated with recent (in the last 6 months) receptive and distributive syringe sharing, multiple sex partners, and unprotected sex risk while controlling for potential individual-level confounders. In bivariate analysis, most of the census-tract-level community characteristics were significantly associated with injection-related HIV risk, while no community characteristics were associated with sex-related risk. However, results from multivariate multilevel models indicate that only percent African American in a census tract was associated with receptive [adjusted odds ratio (AOR) = 0.93; 95% confidence interval (CI) = 0.89, 0.99] and distributive syringe sharing (AOR = 0.94; 95% CI = 0.92, 0.99), net of individual-level characteristics. Accounting for individual-level factors in the multivariate model in the sex-related risk models revealed a significant inverse relationship between percent African American and propensity to engage in unprotected sex (AOR = 0

  19. Micro-epidemiology and spatial heterogeneity of P. vivax parasitaemia in riverine communities of the Peruvian Amazon: A multilevel analysis.

    Science.gov (United States)

    Carrasco-Escobar, Gabriel; Gamboa, Dionicia; Castro, Marcia C; Bangdiwala, Shrikant I; Rodriguez, Hugo; Contreras-Mancilla, Juan; Alava, Freddy; Speybroeck, Niko; Lescano, Andres G; Vinetz, Joseph M; Rosas-Aguirre, Angel; Llanos-Cuentas, Alejandro

    2017-08-14

    Malaria has steadily increased in the Peruvian Amazon over the last five years. This study aimed to determine the parasite prevalence and micro-geographical heterogeneity of Plasmodium vivax parasitaemia in communities of the Peruvian Amazon. Four cross-sectional active case detection surveys were conducted between May and July 2015 in four riverine communities in Mazan district. Analysis of 2785 samples of 820 individuals nested within 154 households for Plasmodium parasitaemia was carried out using light microscopy and qPCR. The spatio-temporal distribution of Plasmodium parasitaemia, dominated by P. vivax, was shown to cluster at both household and community levels. Of enrolled individuals, 47% had at least one P. vivax parasitaemia and 10% P. falciparum, by qPCR, both of which were predominantly sub-microscopic and asymptomatic. Spatial analysis detected significant clustering in three communities. Our findings showed that communities at small-to-moderate spatial scales differed in P. vivax parasite prevalence, and multilevel Poisson regression models showed that such differences were influenced by factors such as age, education, and location of households within high-risk clusters, as well as factors linked to a local micro-geographic context, such as travel and occupation. Complex transmission patterns were found to be related to human mobility among communities in the same micro-basin.

  20. Genetic parameters for social effects on survival in cannibalistic layers: Combining survival analysis and a linear animal model

    Directory of Open Access Journals (Sweden)

    Veerkamp Roel F

    2010-07-01

    Full Text Available Abstract Background Mortality due to cannibalism in laying hens is a difficult trait to improve genetically, because censoring is high (animals still alive at the end of the testing period and it may depend on both the individual itself and the behaviour of its group members, so-called associative effects (social interactions. To analyse survival data, survival analysis can be used. However, it is not possible to include associative effects in the current software for survival analysis. A solution could be to combine survival analysis and a linear animal model including associative effects. This paper presents a two-step approach (2STEP, combining survival analysis and a linear animal model including associative effects (LAM. Methods Data of three purebred White Leghorn layer lines from Institut de Sélection Animale B.V., a Hendrix Genetics company, were used in this study. For the statistical analysis, survival data on 16,780 hens kept in four-bird cages with intact beaks were used. Genetic parameters for direct and associative effects on survival time were estimated using 2STEP. Cross validation was used to compare 2STEP with LAM. LAM was applied directly to estimate genetic parameters for social effects on observed survival days. Results Using 2STEP, total heritable variance, including both direct and associative genetic effects, expressed as the proportion of phenotypic variance, ranged from 32% to 64%. These results were substantially larger than when using LAM. However, cross validation showed that 2STEP gave approximately the same survival curves and rank correlations as LAM. Furthermore, cross validation showed that selection based on both direct and associative genetic effects, using either 2STEP or LAM, gave the best prediction of survival time. Conclusion It can be concluded that 2STEP can be used to estimate genetic parameters for direct and associative effects on survival time in laying hens. Using 2STEP increased the heritable

  1. Community contextual predictors of endoscopic colorectal cancer screening in the USA: spatial multilevel regression analysis

    Directory of Open Access Journals (Sweden)

    Mobley Lee R

    2010-09-01

    Full Text Available Abstract Background Colorectal cancer (CRC is the second leading cause of cancer death in the United States, and endoscopic screening can both detect and prevent cancer, but utilization is suboptimal and varies across geographic regions. We use multilevel regression to examine the various predictors of individuals' decisions to utilize endoscopic CRC screening. Study subjects are a 100% population cohort of Medicare beneficiaries identified in 2001 and followed through 2005. The outcome variable is a binary indicator of any sigmoidoscopy or colonoscopy use over this period. We analyze each state separately and map the findings for all states together to reveal patterns in the observed heterogeneity across states. Results We estimate a fully adjusted model for each state, based on a comprehensive socio-ecological model. We focus the discussion on the independent contributions of each of three community contextual variables that are amenable to policy intervention. Prevalence of Medicare managed care in one's neighborhood was associated with lower probability of screening in 12 states and higher probability in 19 states. Prevalence of poor English language ability among elders in one's neighborhood was associated with lower probability of screening in 15 states and higher probability in 6 states. Prevalence of poverty in one's neighborhood was associated with lower probability of screening in 36 states and higher probability in 5 states. Conclusions There are considerable differences across states in the socio-ecological context of CRC screening by endoscopy, suggesting that the current decentralized configuration of state-specific comprehensive cancer control programs is well suited to respond to the observed heterogeneity. We find that interventions to mediate language barriers are more critically needed in some states than in others. Medicare managed care penetration, hypothesized to affect information about and diffusion of new endoscopic

  2. Socioeconomic and geographic patterning of smoking behaviour in Canada: a cross-sectional multilevel analysis.

    Directory of Open Access Journals (Sweden)

    Daniel J Corsi

    Full Text Available OBJECTIVE: To describe the socioeconomic and geographic distribution of smoking behaviour in Canada among 19,383 individuals (51% women aged 15-85 years. METHODS: Current smoking and quitting were modeled using standard and multilevel logistic regression. Markers of socioeconomic status (SES were education and occupation. Geography was defined by Canadian Provinces. RESULTS: The adjusted prevalence of current smoking was 20.2% (95% confidence interval [CI]: 18.8-21.7 and 63.7% (95% CI: 61.1-66.3 of ever smokers had quit. Current smoking decreased and quitting increased with increasing SES. The adjusted prevalence of current smoking was 32.8% (95% CI: 28.4-37.5 among the least educated compared to 11.0% (95% CI: 8.9-13.4 for the highest educated. Among the least educated, 53.0% (95% CI: 46.8-59.2 had quit, rising to 68.7% (95% CI: 62.7-74.1 for the most educated. There was substantial variation in current smoking and quitting at the provincial level; current smoking varied from 17.9% in British Columbia to 26.1% in Nova Scotia, and quitting varied from 57.4% in Nova Scotia to 67.8% in Prince Edward Island. Nationally, increasing education and occupation level were inversely associated with current smoking (odds ratio [OR] 0.64, 95% CI: 0.60-0.68 for education; OR 0.82, 95% CI: 0.77-0.87 for occupation and positively associated with quitting (OR 1.27, 95% CI: 1.16-1.40 for education; OR 1.20, 95% CI: 1.12-1.27 for occupation. These associations were consistent in direction across provinces although with some variability in magnitude. CONCLUSION: Our findings indicate that socioeconomic inequalities in smoking have persisted in Canada; current smoking was less likely and quitting was more likely among the better off groups and in certain provinces. Current prevention and cessation policies have not been successful in improving the situation for all areas and groups. Future efforts to reduce smoking uptake and increase cessation in Canada will need

  3. Modeling Multi-Level Systems

    CERN Document Server

    Iordache, Octavian

    2011-01-01

    This book is devoted to modeling of multi-level complex systems, a challenging domain for engineers, researchers and entrepreneurs, confronted with the transition from learning and adaptability to evolvability and autonomy for technologies, devices and problem solving methods. Chapter 1 introduces the multi-scale and multi-level systems and highlights their presence in different domains of science and technology. Methodologies as, random systems, non-Archimedean analysis, category theory and specific techniques as model categorification and integrative closure, are presented in chapter 2. Chapters 3 and 4 describe polystochastic models, PSM, and their developments. Categorical formulation of integrative closure offers the general PSM framework which serves as a flexible guideline for a large variety of multi-level modeling problems. Focusing on chemical engineering, pharmaceutical and environmental case studies, the chapters 5 to 8 analyze mixing, turbulent dispersion and entropy production for multi-scale sy...

  4. Job demands, burnout, and engagement among nurses: A multi-level analysis of ORCAB data investigating the moderating effect of teamwork

    OpenAIRE

    Montgomery, Anthony; Spânu, Florina; BĂBAN, ADRIANA; Panagopoulou, Efharis

    2015-01-01

    According to the Job Demands-Resources (JD-R) model, burnout and engagement are psychological reactions that develop when individual characteristics interact with work characteristics. This study tests the JD-R model using multilevel analysis to test the main and moderating effects of teamwork effectiveness among 1156 nurses in 93 departments from seven European countries. Workload, emotional and organizational demands were positively associated with emotional exhaustion, depersonalization, a...

  5. Multilevel modeling using R

    CERN Document Server

    Finch, W Holmes; Kelley, Ken

    2014-01-01

    A powerful tool for analyzing nested designs in a variety of fields, multilevel/hierarchical modeling allows researchers to account for data collected at multiple levels. Multilevel Modeling Using R provides you with a helpful guide to conducting multilevel data modeling using the R software environment.After reviewing standard linear models, the authors present the basics of multilevel models and explain how to fit these models using R. They then show how to employ multilevel modeling with longitudinal data and demonstrate the valuable graphical options in R. The book also describes models fo

  6. Availability of convenience stores and adolescent alcohol use in Taiwan: a multi-level analysis of national surveys.

    Science.gov (United States)

    Wang, Shi-Heng; Lin, I-Chin; Chen, Chuan-Yu; Chen, Duan-Rung; Chan, Ta-Chien; Chen, Wei J

    2013-12-01

    To examine the association between alcohol in school environments and adolescent alcohol use over the previous 6 months. A multi-level logistic regression analysis was performed of cross-sectional surveys conducted in 2004, 2005 and 2006. A total of 52 214 students aged 11-19 years from 387 middle or high schools were selected from a nationally representative, multi-stage, stratified probability sampling across Taiwan. Information on socio-demographic features and substance use experiences was collected using self-administered questionnaires. The alcohol in the environment was measured using the availability of convenience stores surrounding the schools. Using geographical information systems, the weighted numbers of convenience stores within 1 km, a 12-15-minute walk, of a school were calculated. The schools were later categorized into three subgroups via the tertile of nearby convenience stores. Considering the compositional characteristics, the availability of convenience stores was found to account for 1.5% of the school-level variance of youthful drinking. The odds ratios (95% confidence interval) of alcohol use over the previous 6 months among youth attending schools with medium and high availability were 1.04 (0.96-1.13) and 1.08 (1.00-1.17), respectively, with a P-value of 0.04 in the trend test. The greater availability of convenience stores near a school is associated with an increased risk of alcohol use among adolescents over the previous 6 months. © 2013 Society for the Study of Addiction.

  7. Association of regional and cultural factors with the prevalence of rheumatoid arthritis in the Mexican population: a multilevel analysis.

    Science.gov (United States)

    Moreno-Montoya, José; Alvarez-Nemegyei, José; Sanin, Luz Helena; Pérez-Barbosa, Lorena; Trejo-Valdivia, Belem; Santana, Natalia; Goycochea-Robles, Maria Victoria; Cardiel, Mario Humberto; Riega-Torres, Janeth; Maradiaga, Marco; Burgos-Vargas, Rubén; Peláez-Ballestas, Ingris

    2015-03-01

    The overall estimated prevalence of rheumatoid arthritis (RA) in Mexico is 1.6%, but there are major variations in different geographic areas of the country. This study aimed to determine the impact of individual and regional variables on the geographic distribution of RA in Mexico. This multilevel analysis used data from a cross-sectional study that investigated the prevalence of RA among 19,213 individuals older than 18 years throughout 5 geographic regions in Mexico. Logistic regression models were used to determine predictors of RA, including individual and regional variables as well as cultural factors. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were determined. The prevalence of RA varied from 0.77% to 2.8% across the 5 regions. Individual factors associated with RA were sex (OR, 2.32; 95% CI, 1.74-3.07), previous medical diagnosis of RA ( OR 3.3, 95%CI: 2919–5.1 [corrected]), disability (OR, 2.07; 95% CI, 1.48-2.93), and the 56- to 65-year age group (OR, 1.95; 95% CI, 1.08-3.74). The regional factor of speaking an indigenous language had an OR of 2.27 (95% CI, 1.13-4.55). Various individual and regional factors were associated with variations in the prevalence of RA in the Mexican population.

  8. Analysis of a Multilevel Dual Active Bridge (ML-DAB DC-DC Converter Using Symmetric Modulation

    Directory of Open Access Journals (Sweden)

    M. A. Moonem

    2015-04-01

    Full Text Available Dual active bridge (DAB converters have been popular in high voltage, low and medium power DC-DC applications, as well as an intermediate high frequency link in solid state transformers. In this paper, a multilevel DAB (ML-DAB has been proposed in which two active bridges produce two-level (2L-5L, 5L-2L and 3L-5L voltage waveforms across the high frequency transformer. The proposed ML-DAB has the advantage of being used in high step-up/down converters, which deal with higher voltages, as compared to conventional two-level DABs. A three-level neutral point diode clamped (NPC topology has been used in the high voltage bridge, which enables the semiconductor switches to be operated within a higher voltage range without the need for cascaded bridges or multiple two-level DAB converters. A symmetric modulation scheme, based on the least number of angular parameters rather than the duty-ratio, has been proposed for a different combination of bridge voltages. This ML-DAB is also suitable for maximum power point tracking (MPPT control in photovoltaic applications. Steady-state analysis of the converter with symmetric phase-shift modulation is presented and verified using simulation and hardware experiments.

  9. Seroprevalence and Risk Factors of Varicella Zoster Infection in Iranian Adolescents: A Multilevel Analysis; The CASPIAN-III Study.

    Directory of Open Access Journals (Sweden)

    Shervin Ghaffari Hoseini

    Full Text Available The objective of this study was to evaluate the varicella zoster virus (VZV immunity in Iranian adolescents. It was conducted as a primary study for vaccine implementation, and to investigate the association of climatic and socioeconomic factors with the epidemiology of this infection. In this cross- sectional study, anti VZV antibodies were measured in serum samples obtained in a national school-based health survey (CASPIAN- III. Association of demographic, socio-economic, and climate of the living region with the frequency of VZV was investigated by multivariate multilevel analysis. Overall, sera of 2753 individuals aged 10-18 were tested for VZV antibodies, from those 87.4% were positive. The prevalence was statistically different in four socio-geographic regions (P<0.001, varying between 85.24% in West region (mostly mountainous areas with cold climate to 94.59% in Southeast region (subtropical climate. Among variables studied, only age and mean daily temperature of the living area were positively associated with the VZV seroprevalence. Our findings show that most Iranians develop immunity to VZV before the age of 10, but a substantial proportion of them are yet susceptible to the infection. Therefore, it seems that the best strategy to reduce the burden of the disease is to vaccinate high- risk adults, i.e. those without a history of varicella infection. The regional temperature might be the only determinant of VZV epidemiology in Iran.

  10. Venue-level correlates of female sex worker registration status: a multilevel analysis of bars in Tijuana, Mexico.

    Science.gov (United States)

    Gaines, Tommi L; Rusch, Melanie L A; Brouwer, Kimberly C; Goldenberg, Shira M; Lozada, Remedios; Robertson, Angela M; Perkins, Emily; Strathdee, Steffanie A; Patterson, Thomas L

    2013-01-01

    In Tijuana, Mexico, sex work is regulated by the municipal government, through registration cards issued to female sex workers (FSWs) for an annual fee. Registration has been associated with decreased drug use and increase condom use and HIV testing. Previously, it was demonstrated that FSWs operating in bars were more likely than street-based FSWs to be registered. This implies that certain venues may be more accessible to local authorities for the enforcement of this type of programme. Taking a novel multilevel approach, we examined whether venue characteristics of bars reflecting greater organised management and visibility affect registration status of FSWs. In an analysis of venue-level characteristics, predictors of being registered were availability of free condoms at work and distance to the main sex strip; however, these were not independently associated after inclusion of FSWs' income, illicit drug use and history of HIV testing. Our findings suggest that sex work regulations may inadvertently exclude venues in which the more vulnerable and less visible FSWs, such as injection drug users and those with limited financial resources, are situated. Efforts to revise or reconsider sex work regulations to ensure that they best promote FSWs' health, human and labour rights are recommended.

  11. Neighborhood disadvantage and physical aggression in children and adolescents: A systematic review and meta-analysis of multilevel studies.

    Science.gov (United States)

    Chang, Ling-Yin; Wang, Mei-Yeh; Tsai, Pei-Shan

    2016-09-01

    Child and adolescent physical aggression are influenced by multiple contexts, such as peers, family, school, and neighborhood. However, the effect of neighborhoods on youth physical aggression remains unclear. The objective of this study was to quantitatively synthesize studies that have examined the effect of neighborhood disadvantage on physical aggression in children and adolescents and to identify potential moderators. We searched seven databases for articles published before April 25, 2015. Studies were considered eligible if they were published in peer-reviewed journals, used multilevel data, controlled for neighborhood clustering, used physical aggression as the study outcome, and considered children or adolescents as the study population. Of the 152 eligible studies, we included 43 in the meta-analysis. The results from the random-effects model revealed that neighborhood disadvantage was positively and significantly associated with physical aggression (P aggression among studies with younger participants, a higher percentage of female participants, and a longer follow-up period (P aggression. The observed neighborhood effects may also be limited because of the omission of studies that did not provide sufficient information for calculating the pooled effect. In summary, the results provide supporting evidence for the adverse effect of living in disadvantaged neighborhoods on physical aggression after adjusting for the individual-level characteristics of children and adolescents. Interventions targeting structural contexts in neighborhoods are required to assist in reducing physical aggression in young people. Aggr. Behav. 42:441-454, 2016. © 2016 Wiley Periodicals, Inc.

  12. Accumulation of health risk behaviours is associated with lower socioeconomic status and women's urban residence: a multilevel analysis in Japan

    Directory of Open Access Journals (Sweden)

    Takano Takehito

    2005-05-01

    Full Text Available Abstract Background Little is known about the socioeconomic differences in health-related behaviours in Japan. The present study was performed to elucidate the effects of individual and regional socioeconomic factors on selected health risk behaviours among Japanese adults, with a particular focus on regional variations. Methods In a nationally representative sample aged 25 to 59 years old (20,030 men and 21,076 women, the relationships between six risk behaviours (i.e., current smoking, excessive alcohol consumption, poor dietary habits, physical inactivity, stress and non-attendance of health check-ups, individual characteristics (i.e., age, marital status, occupation and household income and regional (N = 60 indicators (per capita income and unemployment rate were examined by multilevel analysis. Results Divorce, employment in women, lower occupational class and lower household income were generally associated with a higher likelihood of risk behaviour. The degrees of regional variation in risk behaviour and the influence of regional indicators were greater in women than in men: higher per capita income was significantly associated with current smoking, excessive alcohol consumption, stress and non-attendance of health check-ups in women. Conclusion Individual lower socioeconomic status was a substantial predictor of risk behaviour in both sexes, while a marked regional influence was observed only in women. The accumulation of risk behaviours in individuals with lower socioeconomic status and in women in areas with higher income, reflecting an urban context, may contribute to their higher mortality rates.

  13. Accumulation of health risk behaviours is associated with lower socioeconomic status and women's urban residence: a multilevel analysis in Japan.

    Science.gov (United States)

    Fukuda, Yoshiharu; Nakamura, Keiko; Takano, Takehito

    2005-05-27

    Little is known about the socioeconomic differences in health-related behaviours in Japan. The present study was performed to elucidate the effects of individual and regional socioeconomic factors on selected health risk behaviours among Japanese adults, with a particular focus on regional variations. In a nationally representative sample aged 25 to 59 years old (20,030 men and 21,076 women), the relationships between six risk behaviours (i.e., current smoking, excessive alcohol consumption, poor dietary habits, physical inactivity, stress and non-attendance of health check-ups), individual characteristics (i.e., age, marital status, occupation and household income) and regional (N = 60) indicators (per capita income and unemployment rate) were examined by multilevel analysis. Divorce, employment in women, lower occupational class and lower household income were generally associated with a higher likelihood of risk behaviour. The degrees of regional variation in risk behaviour and the influence of regional indicators were greater in women than in men: higher per capita income was significantly associated with current smoking, excessive alcohol consumption, stress and non-attendance of health check-ups in women. Individual lower socioeconomic status was a substantial predictor of risk behaviour in both sexes, while a marked regional influence was observed only in women. The accumulation of risk behaviours in individuals with lower socioeconomic status and in women in areas with higher income, reflecting an urban context, may contribute to their higher mortality rates.

  14. Optimization of Survivability Analysis for Large-Scale Engineering Networks

    CERN Document Server

    Poroseva, S V

    2012-01-01

    Engineering networks fall into the category of large-scale networks with heterogeneous nodes such as sources and sinks. The survivability analysis of such networks requires the analysis of the connectivity of the network components for every possible combination of faults to determine a network response to each combination of faults. From the computational complexity point of view, the problem belongs to the class of exponential time problems at least. Partially, the problem complexity can be reduced by mapping the initial topology of a complex large-scale network with multiple sources and multiple sinks onto a set of smaller sub-topologies with multiple sources and a single sink connected to the network of sources by a single link. In this paper, the mapping procedure is applied to the Florida power grid.

  15. The Association of Workplace Social Capital With Work Engagement of Employees in Health Care Settings: A Multilevel Cross-Sectional Analysis.

    Science.gov (United States)

    Fujita, Sumiko; Kawakami, Norito; Ando, Emiko; Inoue, Akiomi; Tsuno, Kanami; Kurioka, Sumiko; Kawachi, Ichiro

    2016-03-01

    The aim of the study was to examine the cross-sectional multilevel association between unit-level workplace social capital and individual-level work engagement among employees in health care settings. The data were collected from employees of a Japanese health care corporation using a questionnaire. The analyses were limited to 440 respondents from 35 units comprising five or more respondents per unit. Unit-level workplace social capital was calculated as an average score of the Workplace Social Capital Scale for each unit. Multilevel regression analysis with a random intercept model was conducted. After adjusting for demographic variables, unit-level workplace social capital was significantly and positively associated with respondents' work engagement (P workplace social capital (P Workplace social capital might exert a positive contextual effect on work engagement of employees in health care settings.

  16. Evaluation of a partial genome screening of two asthma susceptibility regions using bayesian network based bayesian multilevel analysis of relevance.

    Directory of Open Access Journals (Sweden)

    Ildikó Ungvári

    Full Text Available Genetic studies indicate high number of potential factors related to asthma. Based on earlier linkage analyses we selected the 11q13 and 14q22 asthma susceptibility regions, for which we designed a partial genome screening study using 145 SNPs in 1201 individuals (436 asthmatic children and 765 controls. The results were evaluated with traditional frequentist methods and we applied a new statistical method, called bayesian network based bayesian multilevel analysis of relevance (BN-BMLA. This method uses bayesian network representation to provide detailed characterization of the relevance of factors, such as joint significance, the type of dependency, and multi-target aspects. We estimated posteriors for these relations within the bayesian statistical framework, in order to estimate the posteriors whether a variable is directly relevant or its association is only mediated.With frequentist methods one SNP (rs3751464 in the FRMD6 gene provided evidence for an association with asthma (OR = 1.43(1.2-1.8; p = 3×10(-4. The possible role of the FRMD6 gene in asthma was also confirmed in an animal model and human asthmatics.In the BN-BMLA analysis altogether 5 SNPs in 4 genes were found relevant in connection with asthma phenotype: PRPF19 on chromosome 11, and FRMD6, PTGER2 and PTGDR on chromosome 14. In a subsequent step a partial dataset containing rhinitis and further clinical parameters was used, which allowed the analysis of relevance of SNPs for asthma and multiple targets. These analyses suggested that SNPs in the AHNAK and MS4A2 genes were indirectly associated with asthma. This paper indicates that BN-BMLA explores the relevant factors more comprehensively than traditional statistical methods and extends the scope of strong relevance based methods to include partial relevance, global characterization of relevance and multi-target relevance.

  17. Multi-level multi-criteria analysis of alternative fuels for waste collection vehicles in the United States.

    Science.gov (United States)

    Maimoun, Mousa; Madani, Kaveh; Reinhart, Debra

    2016-04-15

    Historically, the U.S. waste collection fleet was dominated by diesel-fueled waste collection vehicles (WCVs); the growing need for sustainable waste collection has urged decision makers to incorporate economically efficient alternative fuels, while mitigating environmental impacts. The pros and cons of alternative fuels complicate the decisions making process, calling for a comprehensive study that assesses the multiple factors involved. Multi-criteria decision analysis (MCDA) methods allow decision makers to select the best alternatives with respect to selection criteria. In this study, two MCDA methods, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Simple Additive Weighting (SAW), were used to rank fuel alternatives for the U.S. waste collection industry with respect to a multi-level environmental and financial decision matrix. The environmental criteria consisted of life-cycle emissions, tail-pipe emissions, water footprint (WFP), and power density, while the financial criteria comprised of vehicle cost, fuel price, fuel price stability, and fueling station availability. The overall analysis showed that conventional diesel is still the best option, followed by hydraulic-hybrid WCVs, landfill gas (LFG) sourced natural gas, fossil natural gas, and biodiesel. The elimination of the WFP and power density criteria from the environmental criteria ranked biodiesel 100 (BD100) as an environmentally better alternative compared to other fossil fuels (diesel and natural gas). This result showed that considering the WFP and power density as environmental criteria can make a difference in the decision process. The elimination of the fueling station and fuel price stability criteria from the decision matrix ranked fossil natural gas second after LFG-sourced natural gas. This scenario was found to represent the status quo of the waste collection industry. A sensitivity analysis for the status quo scenario showed the overall ranking of diesel and

  18. Volumetric and MGMT parameters in glioblastoma patients: Survival analysis

    Directory of Open Access Journals (Sweden)

    Iliadis Georgios

    2012-01-01

    Full Text Available Abstract Background In this study several tumor-related volumes were assessed by means of a computer-based application and a survival analysis was conducted to evaluate the prognostic significance of pre- and postoperative volumetric data in patients harboring glioblastomas. In addition, MGMT (O6-methylguanine methyltransferase related parameters were compared with those of volumetry in order to observe possible relevance of this molecule in tumor development. Methods We prospectively analyzed 65 patients suffering from glioblastoma (GBM who underwent radiotherapy with concomitant adjuvant temozolomide. For the purpose of volumetry T1 and T2-weighted magnetic resonance (MR sequences were used, acquired both pre- and postoperatively (pre-radiochemotherapy. The volumes measured on preoperative MR images were necrosis, enhancing tumor and edema (including the tumor and on postoperative ones, net-enhancing tumor. Age, sex, performance status (PS and type of operation were also included in the multivariate analysis. MGMT was assessed for promoter methylation with Multiplex Ligation-dependent Probe Amplification (MLPA, for RNA expression with real time PCR, and for protein expression with immunohistochemistry in a total of 44 cases with available histologic material. Results In the multivariate analysis a negative impact was shown for pre-radiochemotherapy net-enhancing tumor on the overall survival (OS (p = 0.023 and for preoperative necrosis on progression-free survival (PFS (p = 0.030. Furthermore, the multivariate analysis confirmed the importance of PS in PFS and OS of patients. MGMT promoter methylation was observed in 13/23 (43.5% evaluable tumors; complete methylation was observed in 3/13 methylated tumors only. High rate of MGMT protein positivity (> 20% positive neoplastic nuclei was inversely associated with pre-operative tumor necrosis (p = 0.021. Conclusions Our findings implicate that volumetric parameters may have a significant role in

  19. Evaluating Random Forests for Survival Analysis Using Prediction Error Curves

    Directory of Open Access Journals (Sweden)

    Ulla B. Mogensen

    2012-09-01

    Full Text Available Prediction error curves are increasingly used to assess and compare predictions in survival analysis. This article surveys the R package pec which provides a set of functions for efficient computation of prediction error curves. The software implements inverse probability of censoring weights to deal with right censored data and several variants of cross-validation to deal with the apparent error problem. In principle, all kinds of prediction models can be assessed, and the package readily supports most traditional regression modeling strategies, like Cox regression or additive hazard regression, as well as state of the art machine learning methods such as random forests, a nonparametric method which provides promising alternatives to traditional strategies in low and high-dimensional settings. We show how the functionality of pec can be extended to yet unsupported prediction models. As an example, we implement support for random forest prediction models based on the R packages randomSurvivalForest and party. Using data of the Copenhagen Stroke Study we use pec to compare random forests to a Cox regression model derived from stepwise variable selection.

  20. Analysis and implementation of power managment and control strategy for six-phase multilevel ac drive system in fault condition

    DEFF Research Database (Denmark)

    Sanjeevikumar, P.; Grandi, Gabriele; Blaabjerg, Frede

    2016-01-01

    This research article exploits the power management algorithm in post-fault conditions for a six-phase (quad) multilevel inverter. The drive circuit consists of four 2-level, three-phase voltage source inverter (VSI) supplying a six-phase open-end windings motor or/impedance load, with circumstan......This research article exploits the power management algorithm in post-fault conditions for a six-phase (quad) multilevel inverter. The drive circuit consists of four 2-level, three-phase voltage source inverter (VSI) supplying a six-phase open-end windings motor or/impedance load...... sources. The developed post-fault algorithm is applied when there is a fault by one VSI and the load is fed from the remaining three healthy VSIs. In faulty conditions the multilevel outputs are reduced from 3-level to 2-level, but still the system propagates with degraded power. Numerical simulation...

  1. Assessment of parameter uncertainty in hydrological model using a Markov-Chain-Monte-Carlo-based multilevel-factorial-analysis method

    Science.gov (United States)

    Zhang, Junlong; Li, Yongping; Huang, Guohe; Chen, Xi; Bao, Anming

    2016-07-01

    Without a realistic assessment of parameter uncertainty, decision makers may encounter difficulties in accurately describing hydrologic processes and assessing relationships between model parameters and watershed characteristics. In this study, a Markov-Chain-Monte-Carlo-based multilevel-factorial-analysis (MCMC-MFA) method is developed, which can not only generate samples of parameters from a well constructed Markov chain and assess parameter uncertainties with straightforward Bayesian inference, but also investigate the individual and interactive effects of multiple parameters on model output through measuring the specific variations of hydrological responses. A case study is conducted for addressing parameter uncertainties in the Kaidu watershed of northwest China. Effects of multiple parameters and their interactions are quantitatively investigated using the MCMC-MFA with a three-level factorial experiment (totally 81 runs). A variance-based sensitivity analysis method is used to validate the results of parameters' effects. Results disclose that (i) soil conservation service runoff curve number for moisture condition II (CN2) and fraction of snow volume corresponding to 50% snow cover (SNO50COV) are the most significant factors to hydrological responses, implying that infiltration-excess overland flow and snow water equivalent represent important water input to the hydrological system of the Kaidu watershed; (ii) saturate hydraulic conductivity (SOL_K) and soil evaporation compensation factor (ESCO) have obvious effects on hydrological responses; this implies that the processes of percolation and evaporation would impact hydrological process in this watershed; (iii) the interactions of ESCO and SNO50COV as well as CN2 and SNO50COV have an obvious effect, implying that snow cover can impact the generation of runoff on land surface and the extraction of soil evaporative demand in lower soil layers. These findings can help enhance the hydrological model

  2. University and student segmentation: multilevel latent-class analysis of students' attitudes towards research methods and statistics.

    Science.gov (United States)

    Mutz, Rüdiger; Daniel, Hans-Dieter

    2013-06-01

    It is often claimed that psychology students' attitudes towards research methods and statistics affect course enrollment, persistence, achievement, and course climate. However, the inter-institutional variability has been widely neglected in the research on students' attitudes towards research methods and statistics, but it is important for didactic purposes (heterogeneity of the student population). The paper presents a scale based on findings of the social psychology of attitudes (polar and emotion-based concept) in conjunction with a method for capturing beginning university students' attitudes towards research methods and statistics and identifying the proportion of students having positive attitudes at the institutional level. The study based on a re-analysis of a nationwide survey in Germany in August 2000 of all psychology students that enrolled in fall 1999/2000 (N= 1,490) and N= 44 universities. Using multilevel latent-class analysis (MLLCA), the aim was to group students in different student attitude types and at the same time to obtain university segments based on the incidences of the different student attitude types. Four student latent clusters were found that can be ranked on a bipolar attitude dimension. Membership in a cluster was predicted by age, grade point average (GPA) on school-leaving exam, and personality traits. In addition, two university segments were found: universities with an average proportion of students with positive attitudes and universities with a high proportion of students with positive attitudes (excellent segment). As psychology students make up a very heterogeneous group, the use of multiple learning activities as opposed to the classical lecture course is required. © 2011 The British Psychological Society.

  3. Multivariate Survival Mixed Models for Genetic Analysis of Longevity Traits

    DEFF Research Database (Denmark)

    Pimentel Maia, Rafael; Madsen, Per; Labouriau, Rodrigo

    2013-01-01

    A class of multivariate mixed survival models for continuous and discrete time with a complex covariance structure is introduced in a context of quantitative genetic applications. The methods introduced can be used in many applications in quantitative genetics although the discussion presented...... concentrates on longevity studies. The framework presented allows to combine models based on continuous time with models based on discrete time in a joint analysis. The continuous time models are approximations of the frailty model in which the hazard function will be assumed to be piece-wise constant....... The discrete time models used are multivariate variants of the discrete relative risk models. These models allow for regular parametric likelihood-based inference by exploring a coincidence of their likelihood functions and the likelihood functions of suitably defined multivariate generalized linear mixed...

  4. Multivariate Survival Mixed Models for Genetic Analysis of Longevity Traits

    DEFF Research Database (Denmark)

    Pimentel Maia, Rafael; Madsen, Per; Labouriau, Rodrigo

    2014-01-01

    A class of multivariate mixed survival models for continuous and discrete time with a complex covariance structure is introduced in a context of quantitative genetic applications. The methods introduced can be used in many applications in quantitative genetics although the discussion presented...... concentrates on longevity studies. The framework presented allows to combine models based on continuous time with models based on discrete time in a joint analysis. The continuous time models are approximations of the frailty model in which the hazard function will be assumed to be piece-wise constant....... The discrete time models used are multivariate variants of the discrete relative risk models. These models allow for regular parametric likelihood-based inference by exploring a coincidence of their likelihood functions and the likelihood functions of suitably defined multivariate generalized linear mixed...

  5. Business Bankruptcy Prediction Based on Survival Analysis Approach

    Directory of Open Access Journals (Sweden)

    Ming - Chang Lee

    2014-04-01

    Full Text Available This study sampled companies listed on Taiwan Stock Exchange that examined financial distress between 200 3 and 20 09 . It uses the survival analysis to find the main indicators which can explain the business bankruptcy in Taiwan. This paper use s the Cox P roportional H azard M odel to assess the usefulness of traditional financial ratios and market variables as predictors of the probability of business failure to a given time. This paper presents empirical results of a study regarding 12 financial ratios as predictors of business failure in Taiwan. It showed that it does not need many ratios to be able to anticipate potential business bankruptcy. T he financial distress probability model is constructed using Profitability, Leverage, Efficiency and Valuation ratio variables. In the proposed steps of business failure prediction model , it used detail SAS procedure. The study proves that t he accuracies of classification of the mode in o verall accuracy of classification are 87.93%

  6. Bringing the individual back to small-area variation studies: a multilevel analysis of all-cause mortality in Andalusia, Spain.

    Science.gov (United States)

    Merlo, Juan; Viciana-Fernández, Francisco J; Ramiro-Fariñas, Diego

    2012-10-01

    We performed a multilevel analysis (including individuals, households, census tracts, municipalities and provinces) on a 10% sample (N=230,978) from the Longitudinal Database of the Andalusian Population (LDAP). We aimed to investigate place effects on 8-year individual mortality risk. Moreover, besides calculating association (yielding odds ratios, ORs) between area socio-economic circumstances and individual risk, we wanted to estimate variance and clustering using the variance partition coefficient (VPC). We explicitly proclaim the relevance of considering general contextual effects (i.e. the degree to which the context, as a whole, affects individual variance in mortality risk) under at least two circumstances. The first of these concerns the interpretation of specific contextual effects (i.e. the association between a particular area characteristic and individual risk) obtained from multilevel regression analyses. The second involves the interpretation of geographical variance obtained from classic ecological spatial analyses. The so-called "ecological fallacy" apart, the lack of individual-level information renders geographical variance unrelated to the total individual variation and, therefore, difficult to interpret. Finally, we stress the importance of considering the familial household in multilevel analyses. We observed an association between percentage of people with a low educational level in the census tract and individual mortality risk (OR, highest v. lowest quintile=1.14; 95% confidence interval, CI 1.08-1.20). However, only a minor proportion of the total individual variance in the probability of dying was at the municipality (M) and census tract (CT) levels (VPC(M)=0.2% and VPC(CT)=0.3%). Conversely, the household (H) level appeared much more relevant (VPC(H)=18.6%) than the administrative geographical areas. Without considering general contextual effects, both multilevel analyses of specific contextual effects and ecological studies of small

  7. Hybrid PV/diesel solar power system design using multi-level factor analysis optimization

    Science.gov (United States)

    Drake, Joshua P.

    Solar power systems represent a large area of interest across a spectrum of organizations at a global level. It was determined that a clear understanding of current state of the art software and design methods, as well as optimization methods, could be used to improve the design methodology. Solar power design literature was researched for an in depth understanding of solar power system design methods and algorithms. Multiple software packages for the design and optimization of solar power systems were analyzed for a critical understanding of their design workflow. In addition, several methods of optimization were studied, including brute force, Pareto analysis, Monte Carlo, linear and nonlinear programming, and multi-way factor analysis. Factor analysis was selected as the most efficient optimization method for engineering design as it applied to solar power system design. The solar power design algorithms, software work flow analysis, and factor analysis optimization were combined to develop a solar power system design optimization software package called FireDrake. This software was used for the design of multiple solar power systems in conjunction with an energy audit case study performed in seven Tibetan refugee camps located in Mainpat, India. A report of solar system designs for the camps, as well as a proposed schedule for future installations was generated. It was determined that there were several improvements that could be made to the state of the art in modern solar power system design, though the complexity of current applications is significant.

  8. Multi-level marketing

    OpenAIRE

    Sedlák, Pavel

    2013-01-01

    Bachelor's thesis on "Multilevel marketing" focuses on characterization of multilevel marketing, pyramid schemes and their comparison. The work is divided into three chapters. The first part is devoted to the theme of multilevel marketing and principles of its operation. The main positives and negatives of this system are marked out. The second chapter describes pyramid schemes, their functioning, unsustainability and illegality. It is also devoted to Ponzi scheme. In the last chapter the cha...

  9. Does Maternal Country of Birth Matter for Understanding Offspring's Birthweight? A Multilevel Analysis of Individual Heterogeneity in Sweden.

    Directory of Open Access Journals (Sweden)

    Shai Mulinari

    Full Text Available Many public health and epidemiological studies have found differences between populations (e.g. maternal countries of birth in average values of a health indicator (e.g. mean offspring birthweight. However, the approach based solely on population-level averages compromises our understanding of variability in individuals' health around the averages. If this variability is high, the exclusive study of averages may give misleading information. This idea is relevant when investigating country of birth differences in health.To exemplify this concept, we use information from the Swedish Medical Birth Register (2002-2010 and apply multilevel regression analysis of birthweight, with babies (n = 811,329 at the first, mothers (n = 571,876 at the second, and maternal countries of birth (n = 109 at the third level. We disentangle offspring, maternal and maternal country of birth components of the total offspring heterogeneity in birthweight for babies born within the normal timespan (37-42 weeks. We found that of such birthweight variation about 50% was at the baby level, 47% at the maternal level and only 3% at the maternal countries of birth level.In spite of seemingly large differences in average birthweight among maternal countries of birth (range 3290-3677 g, knowledge of the maternal country of birth does not provide accurate information for ascertaining individual offspring birthweight because of the high inter-offspring heterogeneity around country averages. Our study exemplifies the need for a better understanding of individual health diversity for which group averages may provide insufficient and even misleading information. The analytical approach we outline is therefore relevant to investigations of country of birth (and ethnic differences in health in general.

  10. The weight of place: a multilevel analysis of gender, neighborhood material deprivation, and body mass index among Canadian adults.

    Science.gov (United States)

    Matheson, Flora I; Moineddin, Rahim; Glazier, Richard H

    2008-02-01

    This study examined the impact of neighborhood material deprivation on gender differences in body mass index (BMI) for urban Canadians. Data from a national health survey of adults (Canadian Community Health Survey Cycles 1.1/2.1) were combined with census tract-level neighborhood data from the 2001 census. Using multilevel analysis we found that living in neighborhoods with higher material deprivation was associated with higher BMI. Compared to women living in the most affluent neighborhoods, women living in the most deprived neighborhoods had a BMI score 1.8 points higher. For women 1.65 m in height (5'4'' inches), this translated into a 4.8 kg or 11 lb difference. For men, living in affluent neighborhoods was associated with higher BMI (7 lb) relative to men living in deprived neighborhoods. The relative disadvantage for men living in pockets of affluence and women living in pockets of poverty persisted after adjusting for age, married and visible minority status, educational level, self-perceived stress, sense of belonging, and lifestyle factors, including smoking, exercise, diet, and chronic health conditions. The implication of these disparate findings for men and women is that interventions that lead to healthy weight control may need to be gender responsive. Our findings also suggest that what we traditionally have thought to be triggering factors for weight gain and maintenance of unhealthy BMI-lifestyle and behavioral factors-are not sufficient explanations. Indeed, these factors account for only a portion of the explanation of why neighborhood stress is associated with BMI. Cultural attitudes about the body that pressure women to meet the thin ideal which can lead to an unhealthy cycle of dieting and, subsequent weight gain, and the general acceptability of the heavier male need to be challenged. Education and intervention within a public health framework remain important targets for producing healthy weight.

  11. Minimum Wage and Overweight and Obesity in Adult Women: A Multilevel Analysis of Low and Middle Income Countries.

    Science.gov (United States)

    Conklin, Annalijn I; Ponce, Ninez A; Frank, John; Nandi, Arijit; Heymann, Jody

    2016-01-01

    To describe the relationship between minimum wage and overweight and obesity across countries at different levels of development. A cross-sectional analysis of 27 countries with data on the legislated minimum wage level linked to socio-demographic and anthropometry data of non-pregnant 190,892 adult women (24-49 y) from the Demographic and Health Survey. We used multilevel logistic regression models to condition on country- and individual-level potential confounders, and post-estimation of average marginal effects to calculate the adjusted prevalence difference. We found the association between minimum wage and overweight/obesity was independent of individual-level SES and confounders, and showed a reversed pattern by country development stage. The adjusted overweight/obesity prevalence difference in low-income countries was an average increase of about 0.1 percentage points (PD 0.075 [0.065, 0.084]), and an average decrease of 0.01 percentage points in middle-income countries (PD -0.014 [-0.019, -0.009]). The adjusted obesity prevalence difference in low-income countries was an average increase of 0.03 percentage points (PD 0.032 [0.021, 0.042]) and an average decrease of 0.03 percentage points in middle-income countries (PD -0.032 [-0.036, -0.027]). This is among the first studies to examine the potential impact of improved wages on an important precursor of non-communicable diseases globally. Among countries with a modest level of economic development, higher minimum wage was associated with lower levels of obesity.

  12. A multi-level analysis of the relationship between environmental factors and questing Ixodes ricinus dynamics in Belgium

    Directory of Open Access Journals (Sweden)

    Li Sen

    2012-07-01

    Full Text Available Abstract Background Ticks are the most important pathogen vectors in Europe. They are known to be influenced by environmental factors, but these links are usually studied at specific temporal or spatial scales. Focusing on Ixodes ricinus in Belgium, we attempt to bridge the gap between current “single-sided” studies that focus on temporal or spatial variation only. Here, spatial and temporal patterns of ticks are modelled together. Methods A multi-level analysis of the Ixodes ricinus patterns in Belgium was performed. Joint effects of weather, habitat quality and hunting on field sampled tick abundance were examined at two levels, namely, sampling level, which is associated with temporal dynamics, and site level, which is related to spatial dynamics. Independent variables were collected from standard weather station records, game management data and remote sensing-based land cover data. Results At sampling level, only a marginally significant effect of daily relative humidity and temperature on the abundance of questing nymphs was identified. Average wind speed of seven days prior to the sampling day was found important to both questing nymphs and adults. At site level, a group of landscape-level forest fragmentation indices were highlighted for both questing nymph and adult abundance, including the nearest-neighbour distance, the shape and the aggregation level of forest patches. No cross-level effects or spatial autocorrelation were found. Conclusions Nymphal and adult ticks responded differently to environmental variables at different spatial and temporal scales. Our results can advise spatio-temporal extents of environment data collection for continuing empirical investigations and potential parameters for biological tick models.

  13. Examining intersectoral integration for malaria control programmes in an urban and a rural district in Ghana: a multinomial multilevel analysis

    Directory of Open Access Journals (Sweden)

    Nicodemus Osei Owusu

    2013-08-01

    Full Text Available Background: Intersectoral integration is acknowledged to be essential for improving provision of health care and outcomes, yet it remains one of the main primary health care strategic challenges. Although this is well articulated in the literature, the factors that explain differentials in levels of intersectoral integration have not been systematically studied, particularly in low and middle-income countries. In this study, we examine the levels and determinants of intersectoral integration amongst institutions engaged in malaria control programmes in an urban (Kumasi Metropolitan district and a rural (Ahafo Ano South district in Ghana. Methods: Interviews were conducted with representatives of 32 institutions engaged in promoting malaria prevention and control. The averaging technique proposed by Brown et al. and a two-level multinomial multilevel ordinal logistic regression were used to examine the levels of integration and the factors that explain the differentials. Results: The results show high disparity in levels of integration amongst institutions in the two districts. Integration was higher in the rural district compared to the urban district. The multivariate analysis revealed that the district effect explained 25% of the variations in integration. The type of institution, level of focus on malaria and source of funding are important predictors of intersectoral integration. Conclusion: Although not causal, integrated malaria control programmes could be important for improving malaria-related health outcomes in less developed regions as evident from the rapid decline in malaria fatality rates observed in the Ahafo Ano South district. Harmonisation of programmes should be encouraged amongst institutions and the public and private sectors should be motivated to work in partnership.

  14. Examining intersectoral integration for malaria control programmes in an urban and a rural district in Ghana: a multinomial multilevel analysis

    Directory of Open Access Journals (Sweden)

    Nicodemus Osei Owusu

    2013-08-01

    Full Text Available Background: Intersectoral integration is acknowledged to be essential for improving provision of health care and outcomes, yet it remains one of the main primary health care strategic challenges. Although this is well articulated in the literature, the factors that explain differentials in levels of intersectoral integration have not been systematically studied, particularly in low and middle-income countries. In this study, we examine the levels and determinants of intersectoral integration amongst institutions engaged in malaria control programmes in an urban (Kumasi Metropolitan district and a rural (Ahafo Ano South district in Ghana.Methods: Interviews were conducted with representatives of 32 institutions engaged in promoting malaria prevention and control. The averaging technique proposed by Brown et al. and a two-level multinomial multilevel ordinal logistic regression were used to examine the levels of integration and the factors that explain the differentials.Results: The results show high disparity in levels of integration amongst institutions in the two districts. Integration was higher in the rural district compared to the urban district. The multivariate analysis revealed that the district effect explained 25% of the variations in integration. The type of institution, level of focus on malaria and source of funding are important predictors of intersectoral integration.Conclusion: Although not causal, integrated malaria control programmes could be important for improving malaria-related health outcomes in less developed regions as evident from the rapid decline in malaria fatality rates observed in the Ahafo Ano South district. Harmonisation of programmes should be encouraged amongst institutions and the public and private sectors should be motivated to work in partnership.

  15. Minimum Wage and Overweight and Obesity in Adult Women: A Multilevel Analysis of Low and Middle Income Countries.

    Directory of Open Access Journals (Sweden)

    Annalijn I Conklin

    Full Text Available To describe the relationship between minimum wage and overweight and obesity across countries at different levels of development.A cross-sectional analysis of 27 countries with data on the legislated minimum wage level linked to socio-demographic and anthropometry data of non-pregnant 190,892 adult women (24-49 y from the Demographic and Health Survey. We used multilevel logistic regression models to condition on country- and individual-level potential confounders, and post-estimation of average marginal effects to calculate the adjusted prevalence difference.We found the association between minimum wage and overweight/obesity was independent of individual-level SES and confounders, and showed a reversed pattern by country development stage. The adjusted overweight/obesity prevalence difference in low-income countries was an average increase of about 0.1 percentage points (PD 0.075 [0.065, 0.084], and an average decrease of 0.01 percentage points in middle-income countries (PD -0.014 [-0.019, -0.009]. The adjusted obesity prevalence difference in low-income countries was an average increase of 0.03 percentage points (PD 0.032 [0.021, 0.042] and an average decrease of 0.03 percentage points in middle-income countries (PD -0.032 [-0.036, -0.027].This is among the first studies to examine the potential impact of improved wages on an important precursor of non-communicable diseases globally. Among countries with a modest level of economic development, higher minimum wage was associated with lower levels of obesity.

  16. Analysis of Functional Data with Focus on Multinomial Regression and Multilevel Data

    DEFF Research Database (Denmark)

    Mousavi, Seyed Nourollah

    Functional data analysis (FDA) is a fast growing area in statistical research with increasingly diverse range of application from economics, medicine, agriculture, chemometrics, etc. Functional regression is an area of FDA which has received the most attention both in aspects of application...... and methodological development. Our main Functional data analysis (FDA) is a fast growing area in statistical research with increasingly diverse range of application from economics, medicine, agriculture, chemometrics, etc. Functional regression is an area of FDA which has received the most attention both in aspects...

  17. A comparative analysis of multi-level computer-assisted decision making systems for traumatic injuries

    Directory of Open Access Journals (Sweden)

    Huynh Toan

    2009-01-01

    Full Text Available Abstract Background This paper focuses on the creation of a predictive computer-assisted decision making system for traumatic injury using machine learning algorithms. Trauma experts must make several difficult decisions based on a large number of patient attributes, usually in a short period of time. The aim is to compare the existing machine learning methods available for medical informatics, and develop reliable, rule-based computer-assisted decision-making systems that provide recommendations for the course of treatment for new patients, based on previously seen cases in trauma databases. Datasets of traumatic brain injury (TBI patients are used to train and test the decision making algorithm. The work is also applicable to patients with traumatic pelvic injuries. Methods Decision-making rules are created by processing patterns discovered in the datasets, using machine learning techniques. More specifically, CART and C4.5 are used, as they provide grammatical expressions of knowledge extracted by applying logical operations to the available features. The resulting rule sets are tested against other machine learning methods, including AdaBoost and SVM. The rule creation algorithm is applied to multiple datasets, both with and without prior filtering to discover significant variables. This filtering is performed via logistic regression prior to the rule discovery process. Results For survival prediction using all variables, CART outperformed the other machine learning methods. When using only significant variables, neural networks performed best. A reliable rule-base was generated using combined C4.5/CART. The average predictive rule performance was 82% when using all variables, and approximately 84% when using significant variables only. The average performance of the combined C4.5 and CART system using significant variables was 89.7% in predicting the exact outcome (home or rehabilitation, and 93.1% in predicting the ICU length of stay for

  18. Beyond Traditional School Value-Added Models: A Multilevel Analysis of Complex School Effects in Chile

    Science.gov (United States)

    Troncoso, Patricio; Pampaka, Maria; Olsen, Wendy

    2016-01-01

    School value-added studies have largely demonstrated the effects of socioeconomic and demographic characteristics of the schools and the pupils on performance in standardised tests. Traditionally, these studies have assessed the variation coming only from the schools and the pupils. However, recent studies have shown that the analysis of academic…

  19. School Health Promotion Policies and Adolescent Risk Behaviors in Israel: A Multilevel Analysis

    Science.gov (United States)

    Tesler, Riki; Harel-Fisch, Yossi; Baron-Epel, Orna

    2016-01-01

    Background: Health promotion policies targeting risk-taking behaviors are being implemented across schools in Israel. This study identified the most effective components of these policies influencing cigarette smoking and alcohol consumption among adolescents. Methods: Logistic hierarchical linear model (HLM) analysis of data for 5279 students in…

  20. Collinear Latent Variables in Multilevel Confirmatory Factor Analysis: A Comparison of Maximum Likelihood and Bayesian Estimations

    Science.gov (United States)

    Can, Seda; van de Schoot, Rens; Hox, Joop

    2015-01-01

    Because variables may be correlated in the social and behavioral sciences, multicollinearity might be problematic. This study investigates the effect of collinearity manipulated in within and between levels of a two-level confirmatory factor analysis by Monte Carlo simulation. Furthermore, the influence of the size of the intraclass correlation…

  1. Collinear Latent Variables in Multilevel Confirmatory Factor Analysis: A Comparison of Maximum Likelihood and Bayesian Estimations

    NARCIS (Netherlands)

    Can, Seda; van de Schoot, Rens; Hox, Joop

    2014-01-01

    Because variables may be correlated in the social and behavioral sciences, multicollinearity might be problematic. This study investigates the effect of collinearity manipulated in within and between levels of a two-level confirmatory factor analysis by Monte Carlo simulation. Furthermore, the influ

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

    Science.gov (United States)

    Roeters, Anne

    2013-01-01

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

  3. Macroeconomic Knowledge of Higher Education Students in Germany and Japan--A Multilevel Analysis of Contextual and Personal Effects

    Science.gov (United States)

    Zlatkin-Troitschanskaia, Olga; Schmidt, Susanne; Brückner, Sebastian; Förster, Manuel; Yamaoka, Michio; Asano, Tadayoshi

    2016-01-01

    Recent trends towards harmonising and internationalising business and economics studies in higher education are affecting the structure and content of programmes and courses, and necessitate more transparent and comparable information on students' economic knowledge and skills. In this study, we examine by linear multilevel regression modelling…

  4. Differential School Effects among Low, Middle, and High Social Class Composition Schools: A Multiple Group, Multilevel Latent Growth Curve Analysis

    Science.gov (United States)

    Palardy, Gregory J.

    2008-01-01

    This study uses large-scale survey data and a multiple group, multilevel latent growth curve model to examine differential school effects between low, middle, and high social class composition public schools. The results show that the effects of school inputs and school practices on learning differ across the 3 subpopulations. Moreover, student…

  5. Subjective Health and Mental Well-Being of Adolescents and the Health Promoting School: A Cross-Sectional Multilevel Analysis

    Science.gov (United States)

    Levin, Kate; Inchley, Jo; Currie, Dorothy; Currie, Candace

    2012-01-01

    Purpose: The aim of this paper is to examine the impact of the health promoting school (HPS) on adolescent well-being. Design/methodology/approach: Data from the 2006 Health Behaviour in School-aged Children: WHO-collaborative Study in Scotland were analysed using multilevel linear regression analyses for outcome measures: happiness, confidence,…

  6. Differential School Effects among Low, Middle, and High Social Class Composition Schools: A Multiple Group, Multilevel Latent Growth Curve Analysis

    Science.gov (United States)

    Palardy, Gregory J.

    2008-01-01

    This study uses large-scale survey data and a multiple group, multilevel latent growth curve model to examine differential school effects between low, middle, and high social class composition public schools. The results show that the effects of school inputs and school practices on learning differ across the 3 subpopulations. Moreover, student…

  7. Multilevel modeling and panel data analysis in educational research (Case study: National examination data senior high school in West Java)

    Science.gov (United States)

    Zulvia, Pepi; Kurnia, Anang; Soleh, Agus M.

    2017-03-01

    Individual and environment are a hierarchical structure consist of units grouped at different levels. Hierarchical data structures are analyzed based on several levels, with the lowest level nested in the highest level. This modeling is commonly call multilevel modeling. Multilevel modeling is widely used in education research, for example, the average score of National Examination (UN). While in Indonesia UN for high school student is divided into natural science and social science. The purpose of this research is to develop multilevel and panel data modeling using linear mixed model on educational data. The first step is data exploration and identification relationships between independent and dependent variable by checking correlation coefficient and variance inflation factor (VIF). Furthermore, we use a simple model approach with highest level of the hierarchy (level-2) is regency/city while school is the lowest of hierarchy (level-1). The best model was determined by comparing goodness-of-fit and checking assumption from residual plots and predictions for each model. Our finding that for natural science and social science, the regression with random effects of regency/city and fixed effects of the time i.e multilevel model has better performance than the linear mixed model in explaining the variability of the dependent variable, which is the average scores of UN.

  8. Macroeconomic Knowledge of Higher Education Students in Germany and Japan--A Multilevel Analysis of Contextual and Personal Effects

    Science.gov (United States)

    Zlatkin-Troitschanskaia, Olga; Schmidt, Susanne; Brückner, Sebastian; Förster, Manuel; Yamaoka, Michio; Asano, Tadayoshi

    2016-01-01

    Recent trends towards harmonising and internationalising business and economics studies in higher education are affecting the structure and content of programmes and courses, and necessitate more transparent and comparable information on students' economic knowledge and skills. In this study, we examine by linear multilevel regression modelling…

  9. Individual and Classroom Variables Associated with Relational Aggression in Elementary-School Aged Children: A Multilevel Analysis

    Science.gov (United States)

    Kuppens, S.; Grietens, H.; Onghena, P.; Michiels, D.; Subramanian, S. V.

    2008-01-01

    Relational aggression was studied within classroom environments by examining individual and classroom correlates among 2731 children (3rd-5th graders) during two successive measurement years. Multilevel analyses yielded small gender differences for relational aggression, indicating that such aggressive behavior was more associated with girls as…

  10. Global Multi-Level Analysis of the ‘Scientific Food Web'

    Science.gov (United States)

    Mazloumian, Amin; Helbing, Dirk; Lozano, Sergi; Light, Robert P.; Börner, Katy

    2013-01-01

    We introduce a network-based index analyzing excess scientific production and consumption to perform a comprehensive global analysis of scholarly knowledge production and diffusion on the level of continents, countries, and cities. Compared to measures of scientific production and consumption such as number of publications or citation rates, our network-based citation analysis offers a more differentiated picture of the `ecosystem of science'. Quantifying knowledge flows between 2000 and 2009, we identify global sources and sinks of knowledge production. Our knowledge flow index reveals, where ideas are born and consumed, thereby defining a global `scientific food web'. While Asia is quickly catching up in terms of publications and citation rates, we find that its dependence on knowledge consumption has further increased.

  11. A Novel Quantitative Analysis Model for Information System Survivability Based on Conflict Analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; WANG Huiqiang; ZHAO Guosheng

    2007-01-01

    This paper describes a novel quantitative analysis model for system survivability based on conflict analysis, which provides a direct-viewing survivable situation. Based on the three-dimensional state space of conflict, each player's efficiency matrix on its credible motion set can be obtained. The player whose desire is the strongest in all initiates the moving and the overall state transition matrix of information system may be achieved. In addition, the process of modeling and stability analysis of conflict can be converted into a Markov analysis process, thus the obtained results with occurring probability of each feasible situation will help the players to quantitatively judge the probability of their pursuing situations in conflict. Compared with the existing methods which are limited to post-explanation of system's survivable situation, the proposed model is relatively suitable for quantitatively analyzing and forecasting the future development situation of system survivability. The experimental results show that the model may be effectively applied to quantitative analysis for survivability. Moreover, there will be a good application prospect in practice.

  12. Prognostic analysis of orthostatic intolerance using survival model in children

    Institute of Scientific and Technical Information of China (English)

    Li Yawen; Li Hongxia; Li Xueying; Li Xiaoming; Jin Hongfang

    2014-01-01

    Background Orthostatic intolerance (Ol) is a common disease at pediatric period which has a serious impact on physical and mental health of children.The purpose of this study was to investigate the effect of related factors on the prognosis of children with Ol.Methods The subjects were 170 children with Ol,including 71 males (41.8%) and 99 females (58.2%) with age from 6 to 17 (12.0±2.6) years.The effect of related factors on the prognosis of children was studied by using univariate analysis.Then,the impact of children's age,symptom score,duration,disease subtype,and treatment on patient's prognosis was studied via analysis of COX proportional conversion model.Results Among 170 cases,48 were diagnosed with vasovagal syncope,including 28 cases of vasoinhibitory type,16 cases of mixed type,and 4 cases of cardioinhibitory type; 115 cases were diagnosed with postural tachycardia syndrome and 7 cases with orthostatic hypotension.By using univariate analysis of Cox regression,the results showed that symptom score had a marked impact on the time of symptoms improvement of children after taking medication (P <0.05),while other univariates had no impact (P >0.05).Multivariate analysis using Cox proportional hazards regression model showed that the symptom score at diagnosis had a significant effect on holding time of symptoms improvement of children after taking medication (P <0.05).Kaplan-Meier curve showed that symptom-free survival was higher in children with symptom score equal to 1 than children with symptom score equal to or greater than 2 during follow-up (P <0.05).Conclusion Symptom score is an important factor affecting the time of symptom improvement after treatment for children with Ol.

  13. Multi-level model for 2D human motion analysis and description

    Science.gov (United States)

    Foures, Thomas; Joly, Philippe

    2003-01-01

    This paper deals with the proposition of a model for human motion analysis in a video. Its main caracteristic is to adapt itself automatically to the current resolution, the actual quality of the picture, or the level of precision required by a given application, due to its possible decomposition into several hierarchical levels. The model is region-based to address some analysis processing needs. The top level of the model is only defined with 5 ribbons, which can be cut into sub-ribbons regarding to a given (or an expected) level of details. Matching process between model and current picture consists in the comparison of extracted subject shape with a graphical rendering of the model built on the base of some computed parameters. The comparison is processed by using a chamfer matching algorithm. In our developments, we intend to realize a platform of interaction between a dancer and tools synthetizing abstract motion pictures and music in the conditions of a real-time dialogue between a human and a computer. In consequence, we use this model in a perspective of motion description instead of motion recognition: no a priori gestures are supposed to be recognized as far as no a priori application is specially targeted. The resulting description will be made following a Description Scheme compliant with the movement notation called "Labanotation".

  14. A multilevel analysis of the interpersonal behavior of socially anxious people.

    Science.gov (United States)

    Oakman, Jonathan; Gifford, Shannon; Chlebowsky, Natasha

    2003-06-01

    We investigate the interpersonal behavior of socially anxious (SA) and non-socially anxious (NSA) individuals at three different levels of analysis, focusing on the dimensions of warmth and dominance. Study 1 examines self-reported general interaction styles, Study 2 explores behavior occurring within the context of a single interaction, and in Study 3 we focus on the performance of a single conversational act (a disagreement). Studies 1 and 2 adopt the framework of Interpersonal Circumplex Theory (IPC; Kiesler, 1983), which is well suited for studying trait-level and interaction-level social behaviors, while Study 3 is grounded in Politeness Theory (PT; Brown & Levinson, 1987), which can be used to analyze individual acts at the microstructural level. The potential mutual relevance of PT and IPC is also discussed.

  15. Immigrant students' emotional and cognitive engagement at school: a multilevel analysis of students in 41 countries.

    Science.gov (United States)

    Chiu, Ming Ming; Pong, Suet-ling; Mori, Izumi; Chow, Bonnie Wing-Yin

    2012-11-01

    Central to student learning and academic success, the school engagement of immigrant children also reflects their adaptation to a primary institution in their new country. Analysis of questionnaire responses of 276,165 fifteen-year-olds (50 % female) and their 10,789 school principals in 41 countries showed that school engagement has distinct, weakly-linked cognitive and emotional components. Native students had weaker attitudes toward school (cognitive engagement) but greater sense of belonging at school (emotional engagement) than immigrant students or students who spoke a foreign language at home. Students with better teacher-student relationships, teacher support or a classroom disciplinary climate often had a greater sense of belonging at school and had better attitudes toward school than other students. While immigrant students often have solid attitudes toward school, teachers can help them feel a greater sense of belonging at school.

  16. In Search of a Network Organization for Innovation: A Multilevel Analysis on Transnational Corporations' Global Innovation

    DEFF Research Database (Denmark)

    Hu, Yimei

    2013-01-01

    on the description and analysis of the Danish triple helix’s innovation activities in China, Paper 2 proposes a stage-model of the internationalization of the triple helix, consisting of three stages, i.e. pioneering, exploration and integration stage. In the pioneering stage, we see the establishment of each...... and needs to be applied in both intra-and interorganizational network organizations. The way the dissertation has been designed has given rise to both theoretical and practical implications. Regarding the theoretical contribution, the dissertation expands our knowledge by contributing to the theories...... of global innovation organization and management. For example, the dissertation expands the triple helix model by adding an internationalization dimension, and elaborates and expands the emerging concepts of relational competitive advantages and orchestration capabilities. The findings of the dissertation...

  17. Multilevel Analysis of Oscillation Motions in Active Regions of the Sun

    CERN Document Server

    Abramov-Maximov, V E; Kobanov, N I; Shibasaki, K; Chupin, S A; 10.1007/s11207-011-9716-7

    2011-01-01

    We present a new method that combines the results of an oscillation study made in optical and radio observations. The optical spectral measurements in photospheric and chromospheric lines of the line-of-sight velocity were carried out at the Sayan Solar Observatory. The radio maps of the Sun were obtained with the Nobeyama Radioheliograph at 1.76 cm. Radio sources associated with the sunspots were analyzed to study the oscillation processes in the chromosphere-corona transition region in the layer with magnetic field B=2000 G. A high level of instability of the oscillations in the optical and radio data was found. We used a wavelet analysis for the spectra. The best similarities of the spectra of oscillations obtained by the two methods were detected in the three-minute oscillations inside the sunspot umbra for the dates when the active regions were situated near the center of the solar disk. A comparison of the wavelet spectra for optical and radio observations showed a time delay of about 50 seconds of the ...

  18. Analysis of a Multilevel Diagnosis Decision Support System and Its Implications: A Case Study

    Directory of Open Access Journals (Sweden)

    Alejandro Rodríguez-González

    2012-01-01

    Full Text Available Medical diagnosis can be performed in an automatic way with the use of computer-based systems or algorithms. Such systems are usually called diagnostic decision support systems (DDSSs or medical diagnosis systems (MDSs. An evaluation of the performance of a DDSS called ML-DDSS has been performed in this paper. The methodology is based on clinical case resolution performed by physicians which is then used to evaluate the behavior of ML-DDSS. This methodology allows the calculation of values for several well-known metrics such as precision, recall, accuracy, specificity, and Matthews correlation coefficient (MCC. Analysis of the behavior of ML-DDSS reveals interesting results about the behavior of the system and of the physicians who took part in the evaluation process. Global results show how the ML-DDSS system would have significant utility if used in medical practice. The MCC metric reveals an improvement of about 30% in comparison with the experts, and with respect to sensitivity the system returns better results than the experts.

  19. Analysis of a Multilevel Diagnosis Decision Support System and Its Implications: A Case Study

    Science.gov (United States)

    Rodríguez-González, Alejandro; Torres-Niño, Javier; Mayer, Miguel A.; Alor-Hernandez, Giner; Wilkinson, Mark D.

    2012-01-01

    Medical diagnosis can be performed in an automatic way with the use of computer-based systems or algorithms. Such systems are usually called diagnostic decision support systems (DDSSs) or medical diagnosis systems (MDSs). An evaluation of the performance of a DDSS called ML-DDSS has been performed in this paper. The methodology is based on clinical case resolution performed by physicians which is then used to evaluate the behavior of ML-DDSS. This methodology allows the calculation of values for several well-known metrics such as precision, recall, accuracy, specificity, and Matthews correlation coefficient (MCC). Analysis of the behavior of ML-DDSS reveals interesting results about the behavior of the system and of the physicians who took part in the evaluation process. Global results show how the ML-DDSS system would have significant utility if used in medical practice. The MCC metric reveals an improvement of about 30% in comparison with the experts, and with respect to sensitivity the system returns better results than the experts. PMID:23320043

  20. Are neighborhood bonding and bridging social capital protective against depressive mood in old age? A multilevel analysis in Japan.

    Science.gov (United States)

    Murayama, Hiroshi; Nofuji, Yu; Matsuo, Eri; Nishi, Mariko; Taniguchi, Yu; Fujiwara, Yoshinori; Shinkai, Shoji

    2015-01-01

    While the importance of distinguishing between bonding and bridging social capital is now understood, evidence remains sparse on their contextual effects on health. We examined the associations of neighborhood bonding and bridging social capital with depressive mood among older Japanese. A questionnaire survey of all community residents aged 65 and older in the city of Yabu, Hyogo Prefecture, Japan was conducted in July and August 2012. Bonding and bridging social capital were assessed by evaluating individual homogeneous and heterogeneous social networks in relation to age, gender, and socioeconomic status. Individual responses in each neighborhood were aggregated to create an index of neighborhood-level bonding/bridging social capital. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the associations of such social capital with depressive mood using multilevel binomial logistic regression analysis. Of the 7271 questionnaires distributed, 6416 were analyzed (covering 152 administrative neighborhoods). Approximately 56.8% of respondents were women, and the mean age was 76.2 ± 7.1 years. Neighborhood-level bonding social capital was inversely associated with depressive mood (OR = 0.84, 95% CI = 0.75-0.94), but neighborhood-level bridging social capital was not. Gender-stratified analysis revealed that neighborhood-level bonding social capital was inversely associated with depressive mood in both genders (OR = 0.83, 95% CI = 0.72-0.96 for men; OR = 0.85, 95% CI = 0.72-0.99 for women), while neighborhood-level bridging social capital was positively associated with depressive mood in women (OR = 1.15, 95% CI = 1.00-1.34). There was also a significant interaction between individual- and neighborhood-level bonding social capital, indicating that people with a weaker homogeneous network and living in a neighborhood with weaker bonding social capital were more likely to have depressive mood. Our results suggest that neighborhood social

  1. Multilevel and Diverse Classrooms

    Science.gov (United States)

    Baurain, Bradley, Ed.; Ha, Phan Le, Ed.

    2010-01-01

    The benefits and advantages of classroom practices incorporating unity-in-diversity and diversity-in-unity are what "Multilevel and Diverse Classrooms" is all about. Multilevel classrooms--also known as mixed-ability or heterogeneous classrooms--are a fact of life in ESOL programs around the world. These classrooms are often not only multilevel…

  2. Multilevel ensemble Kalman filter

    KAUST Repository

    Chernov, Alexey

    2016-01-06

    This work embeds a multilevel Monte Carlo (MLMC) sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF). In terms of computational cost vs. approximation error the asymptotic performance of the multilevel ensemble Kalman filter (MLEnKF) is superior to the EnKF s.

  3. Organizational performance impacting patient satisfaction in Ontario hospitals: a multilevel analysis.

    Science.gov (United States)

    Koné Péfoyo, Anna J; Wodchis, Walter P

    2013-12-05

    Patient satisfaction in health care constitutes an important component of organizational performance in the hospital setting. Satisfaction measures have been developed and used to evaluate and improve hospital performance, quality of care and physician practice. In order to direct improvement strategies, it is necessary to evaluate both individual and organizational factors that can impact patients' perception of care. The study aims were to determine the dimensions of patient satisfaction, and to analyze the individual and organizational determinants of satisfaction dimensions in hospitals. We used patient and hospital survey data as well as administrative data collected for a 2008 public hospital report in Ontario, Canada. We evaluated the clustering of patient survey items with exploratory factor analysis and derived plausible dimensions of satisfaction. A two-level multivariate model was fitted to analyze the determinants of satisfaction. We found eight satisfaction factors, with acceptable to good level of loadings and good reliability. More than 95% of variation in patient satisfaction scores was attributable to patient-level variation, with less than 5% attributable to hospital-level variation. The hierarchical models explain 5 to 17% of variation at the patient level and up to 52% of variation between hospitals. Individual patient characteristics had the strongest association with all dimensions of satisfaction. Few organizational performance indicators are associated with patient satisfaction and significant determinants differ according to the satisfaction dimension. The research findings highlight the importance of adjusting for both patient-level and organization-level characteristics when evaluating patient satisfaction. Better understanding and measurement of organization-level activities and processes associated with patient satisfaction could contribute to improved satisfaction ratings and care quality.

  4. Heterogeneity in Patient-Reported Outcomes following Low-Intensity Mental Health Interventions: A Multilevel Analysis

    Science.gov (United States)

    Ali, Shehzad; Littlewood, Elizabeth; McMillan, Dean; Delgadillo, Jaime; Miranda, Alfonso; Croudace, Tim; Gilbody, Simon

    2014-01-01

    Background Variability in patient-reported outcomes of psychological treatments has been partly attributed to therapists – a phenomenon commonly known as therapist effects. Meta-analytic reviews reveal wide variation in therapist-attributable variability in psychotherapy outcomes, with most studies reporting therapist effects in the region of 5% to 10% and some finding minimal to no therapist effects. However, all except one study to date have been conducted in high-intensity or mixed intervention groups; therefore, there is scarcity of evidence on therapist effects in brief low-intensity psychological interventions. Objective To examine therapist effects in low-intensity interventions for depression and anxiety in a naturalistic setting. Data and Analysis Session-by-session data on patient-reported outcome measures were available for a cohort of 1,376 primary care psychotherapy patients treated by 38 therapists. Outcome measures included PHQ-9 (sensitive to depression) and GAD-7 (sensitive to general anxiety disorder) measures. Three-level hierarchical linear modelling was employed to estimate therapist-attributable proportion of variance in clinical outcomes. Therapist effects were evaluated using the intra-cluster correlation coefficient (ICC) and Bayesian empirical predictions of therapist random effects. Three sensitivity analyses were conducted: 1) using both treatment completers and non-completers; 2) a sub-sample of cases with baseline scores above the conventional clinical thresholds for PHQ-9 and GAD-7; and 3) a two-level model (using patient-level pre- and post-treatment scores nested within therapists). Results The ICC estimates for all outcome measures were very small, ranging between 0% and 1.3%, although most were statistically significant. The Bayesian empirical predictions showed that therapist random effects were not statistically significantly different from each other. Between patient variability explained most of the variance in outcomes

  5. Job demands, burnout, and engagement among nurses: A multi-level analysis of ORCAB data investigating the moderating effect of teamwork.

    Science.gov (United States)

    Montgomery, Anthony; Spânu, Florina; Băban, Adriana; Panagopoulou, Efharis

    2015-09-01

    According to the Job Demands-Resources (JD-R) model, burnout and engagement are psychological reactions that develop when individual characteristics interact with work characteristics. This study tests the JD-R model using multilevel analysis to test the main and moderating effects of teamwork effectiveness among 1156 nurses in 93 departments from seven European countries. Workload, emotional and organizational demands were positively associated with emotional exhaustion, depersonalization, and negatively with vigor. Emotional and organizational demands were negatively associated with dedication. Teamwork effectiveness was positively associated with engagement. We found no evidence for the moderating effect of teamwork effectiveness in reducing individual perceptions of demands.

  6. Job demands, burnout, and engagement among nurses: A multi-level analysis of ORCAB data investigating the moderating effect of teamwork

    Science.gov (United States)

    Montgomery, Anthony; Spânu, Florina; Băban, Adriana; Panagopoulou, Efharis

    2015-01-01

    According to the Job Demands-Resources (JD-R) model, burnout and engagement are psychological reactions that develop when individual characteristics interact with work characteristics. This study tests the JD-R model using multilevel analysis to test the main and moderating effects of teamwork effectiveness among 1156 nurses in 93 departments from seven European countries. Workload, emotional and organizational demands were positively associated with emotional exhaustion, depersonalization, and negatively with vigor. Emotional and organizational demands were negatively associated with dedication. Teamwork effectiveness was positively associated with engagement. We found no evidence for the moderating effect of teamwork effectiveness in reducing individual perceptions of demands. PMID:26877971

  7. Just how multi-level is leadership research? : A document co-citation analysis 1980–2013 on leadership constructs and outcomes

    NARCIS (Netherlands)

    Batistic, S.; Cerne, Matej; Vogel, Bernd

    2016-01-01

    The use of multi-level theories and methodologies in leadership has gained momentum in recent years. However, the leadership field still suffers from a fragmented and unclear evolution and practice of multi-level approaches. The questions of how and to what extent multi-level research has evolved in

  8. Affective Balance, Team Prosocial Efficacy and Team Trust: A Multilevel Analysis of Prosocial Behavior in Small Groups.

    Science.gov (United States)

    Cuadrado, Esther; Tabernero, Carmen

    2015-01-01

    Little research has focused on how individual- and team-level characteristics jointly influence, via interaction, how prosocially individuals behave in teams and few studies have considered the potential influence of team context on prosocial behavior. Using a multilevel perspective, we examined the relationships between individual (affective balance) and group (team prosocial efficacy and team trust) level variables and prosocial behavior towards team members. The participants were 123 students nested in 45 small teams. A series of multilevel random models was estimated using hierarchical linear and nonlinear modeling. Individuals were more likely to behave prosocially towards in-group members when they were feeling good. Furthermore, the relationship between positive affective balance and prosocial behavior was stronger in teams with higher team prosocial efficacy levels as well as in teams with higher team trust levels. Finally, the relevance of team trust had a stronger influence on behavior than team prosocial efficacy.

  9. Affective Balance, Team Prosocial Efficacy and Team Trust: A Multilevel Analysis of Prosocial Behavior in Small Groups.

    Directory of Open Access Journals (Sweden)

    Esther Cuadrado

    Full Text Available Little research has focused on how individual- and team-level characteristics jointly influence, via interaction, how prosocially individuals behave in teams and few studies have considered the potential influence of team context on prosocial behavior. Using a multilevel perspective, we examined the relationships between individual (affective balance and group (team prosocial efficacy and team trust level variables and prosocial behavior towards team members. The participants were 123 students nested in 45 small teams. A series of multilevel random models was estimated using hierarchical linear and nonlinear modeling. Individuals were more likely to behave prosocially towards in-group members when they were feeling good. Furthermore, the relationship between positive affective balance and prosocial behavior was stronger in teams with higher team prosocial efficacy levels as well as in teams with higher team trust levels. Finally, the relevance of team trust had a stronger influence on behavior than team prosocial efficacy.

  10. Integrated genomic analysis of survival outliers in glioblastoma.

    Science.gov (United States)

    Peng, Sen; Dhruv, Harshil; Armstrong, Brock; Salhia, Bodour; Legendre, Christophe; Kiefer, Jeffrey; Parks, Julianna; Virk, Selene; Sloan, Andrew E; Ostrom, Quinn T; Barnholtz-Sloan, Jill S; Tran, Nhan L; Berens, Michael E

    2017-06-01

    To elucidate molecular features associated with disproportionate survival of glioblastoma (GB) patients, we conducted deep genomic comparative analysis of a cohort of patients receiving standard therapy (surgery plus concurrent radiation and temozolomide); "GB outliers" were identified: long-term survivor of 33 months (LTS; n = 8) versus short-term survivor of 7 months (STS; n = 10). We implemented exome, RNA, whole genome sequencing, and DNA methylation for collection of deep genomic data from STS and LTS GB patients. LTS GB showed frequent chromosomal gains in 4q12 (platelet derived growth factor receptor alpha and KIT) and 12q14.1 (cyclin-dependent kinase 4), and deletion in 19q13.33 (BAX, branched chain amino-acid transaminase 2, and cluster of differentiation 33). STS GB showed frequent deletion in 9p11.2 (forkhead box D4-like 2 and aquaporin 7 pseudogene 3) and 22q11.21 (Hypermethylated In Cancer 2). LTS GB showed 2-fold more frequent copy number deletions compared with STS GB. Gene expression differences showed the STS cohort with altered transcriptional regulators: activation of signal transducer and activator of transcription (STAT)5a/b, nuclear factor-kappaB (NF-κB), and interferon-gamma (IFNG), and inhibition of mitogen-activated protein kinase (MAPK1), extracellular signal-regulated kinase (ERK)1/2, and estrogen receptor (ESR)1. Expression-based biological concepts prominent in the STS cohort include metabolic processes, anaphase-promoting complex degradation, and immune processes associated with major histocompatibility complex class I antigen presentation; the LTS cohort features genes related to development, morphogenesis, and the mammalian target of rapamycin signaling pathway. Whole genome methylation analyses showed that a methylation signature of 89 probes distinctly separates LTS from STS GB tumors. We posit that genomic instability is associated with longer survival of GB (possibly with vulnerability to standard therapy); conversely, genomic

  11. Is Preventative Long-Segment Surgery for Multi-Level Spondylolysis Necessary? A Finite Element Analysis Study.

    Directory of Open Access Journals (Sweden)

    Jianqiang Mo

    Full Text Available For multi-level spondylolysis patients, surgeons commonly choose to fix all the segments with pars interarticularis defect even those without slippage and not responsible for clinical symptoms. In this study, we tried to study the necessity of the preventative long-segment surgery for the defected segment without slippage in treatment of multi-level spondylolysis patients from a biomechanical perspective.We established a bi-level spondylolysis model with pars defects at L4 and L5 segments, and simulated posterior lumbar interbody fusion (PLIF and pedicle screw fixation at L5-S1 level. Then we compared the biomechanical changes at L4 segment before and after surgery in neutral, flexion, extension, lateral bending and axial rotation position.The stress on L4 pars interarticularis was very similar before and after surgery, and reached the highest in axial rotation. The L3-L4 intradiscal pressure was almost the same, while L4-L5 intradiscal pressure changed a little in lateral bending (increase from 1.993 to 2.160 MPa and axial rotation (decrease from 1.639 to 1.307 MPa after surgery. The PLIF surgery caused a little increase of range of motion at adjacent L4-L5 and L3-L4 levels, but the change is very tiny (1 degree.The PLIF surgery will not cause significant biomechanical change at adjacent segment with pars defect in multi-level spondylolysis. On the contrary, excessive long-segment surgery will damage surrounding soft tissues which are important for maintaining the stability of spine. So a preventative long-segment surgery is not necessary for multi-level spondylolysis as long as there are no soft tissue degeneration signs at adjacent level.

  12. A multilevel analysis of tobacco use and tobacco consumption levels in France: are there any combination risk groups?

    OpenAIRE

    Chaix, Basile; Guilbert, Philippe; Chauvin, Pierre

    2004-01-01

    International audience; BACKGROUND: Both the predictors for tobacco use and the determinants of the amounts of tobacco consumed by smokers should be taken into account when designing prevention programmes. METHODS: Using a sample of 12,948 individuals representative of the French population in 1999, multilevel models were used to carry out a comparative investigation for the predictors of tobacco use and the determinants of the amount of tobacco consumed by smokers. RESULTS: At the individual...

  13. Association of workplace and population characteristics with prevalence of hypertension among Brazilian industry workers: a multilevel analysis.

    Science.gov (United States)

    Vinholes, Daniele B; Bassanesi, Sérgio L; Chaves Junior, Hilton de Castro; Machado, Carlos Alberto; Melo, Ione M F; Fuchs, Flavio Danni; Fuchs, Sandra Costa

    2017-08-21

    Exposure to risk factors for hypertension may be influenced by the characteristics of the workplace, where workers spend most of their daily time. To evaluate the association between features of the companies, particularly the presence of facilities to provide meals, and of population characteristics and the prevalence of hypertension, taking into account individual risk factors for hypertension. This multilevel analysis was based on a cross-sectional study with individual and company data from the SESI (Serviço Social da Indústria-Social Service of Industries) study and population-based data from the national census statistics. Workers aged ≥15 years were randomly selected from small (20-99), medium (100-499) and large (≥500 employees) companies per state using multistage sampling. Logistic regression was used to analyse the association between hypertension and individual, workplace and population variables, with odds ratios (ORs; 95% CI) adjusted for three-level variables. 4818 Workers from 157 companies were interviewed and their blood pressure, weight and height were measured. Overall, 77% were men, aged 35.4 ±10.7 years, with 8.7 ±4.1 years of schooling and mostly worked in companies with a staff canteen (66%). Besides individual characteristics-being male, ageing, low schooling, alcohol abuse and higher BMI-a workplace with no staff canteen (OR=1.28; 95% CI 1.08 to 1.52), small companies (OR=1.31; 95% CI 1.07 to 1.60) and living in cities with higher economic inequality (OR=1.47; 95% CI 1.23 to 1.76) were associated with a higher risk for hypertension. Among Brazilian workers, the prevalence of hypertension is associated with individual risk factors, lack of a canteen at the workplace, small companies and higher economic inequalities of cities. These three-level characteristics help to interpret differences in the prevalence of hypertension between regions or countries. © Article author(s) (or their employer(s) unless otherwise stated in the

  14. Individual and setting level predictors of the implementation of a skin cancer prevention program: a multilevel analysis

    Directory of Open Access Journals (Sweden)

    Brownson Ross C

    2010-05-01

    Full Text Available Abstract Background To achieve widespread cancer control, a better understanding is needed of the factors that contribute to successful implementation of effective skin cancer prevention interventions. This study assessed the relative contributions of individual- and setting-level characteristics to implementation of a widely disseminated skin cancer prevention program. Methods A multilevel analysis was conducted using data from the Pool Cool Diffusion Trial from 2004 and replicated with data from 2005. Implementation of Pool Cool by lifeguards was measured using a composite score (implementation variable, range 0 to 10 that assessed whether the lifeguard performed different components of the intervention. Predictors included lifeguard background characteristics, lifeguard sun protection-related attitudes and behaviors, pool characteristics, and enhanced (i.e., more technical assistance, tailored materials, and incentives are provided versus basic treatment group. Results The mean value of the implementation variable was 4 in both years (2004 and 2005; SD = 2 in 2004 and SD = 3 in 2005 indicating a moderate implementation for most lifeguards. Several individual-level (lifeguard characteristics and setting-level (pool characteristics and treatment group factors were found to be significantly associated with implementation of Pool Cool by lifeguards. All three lifeguard-level domains (lifeguard background characteristics, lifeguard sun protection-related attitudes and behaviors and six pool-level predictors (number of weekly pool visitors, intervention intensity, geographic latitude, pool location, sun safety and/or skin cancer prevention programs, and sun safety programs and policies were included in the final model. The most important predictors of implementation were the number of weekly pool visitors (inverse association and enhanced treatment group (positive association. That is, pools with fewer weekly visitors and pools in the enhanced

  15. Study of Hip Fracture Risk using Tree Structured Survival Analysis

    Directory of Open Access Journals (Sweden)

    Lu Y

    2003-01-01

    Full Text Available In dieser Studie wird das Hüftfraktur-Risiko bei postmenopausalen Frauen untersucht, indem die Frauen in verschiedene Subgruppen hinsichtlich dieses Risikos klassifiziert werden. Frauen in einer gemeinsamen Subgruppe haben ein ähnliches Risiko, hingegen in verschiedenen Subgruppen ein unterschiedliches Hüftfraktur-Risiko. Die Subgruppen wurden mittels der Tree Structured Survival Analysis (TSSA aus den Daten von 7.665 Frauen der SOF (Study of Osteoporosis Fracture ermittelt. Bei allen Studienteilnehmerinnen wurde die Knochenmineraldichte (BMD von Unterarm, Oberschenkelhals, Hüfte und Wirbelsäule gemessen. Die Zeit von der BMD-Messung bis zur Hüftfraktur wurde als Endpunkt notiert. Eine Stichprobe von 75% der Teilnehmerinnen wurde verwendet, um die prognostischen Subgruppen zu bilden (Trainings-Datensatz, während die anderen 25% als Bestätigung der Ergebnisse diente (Validierungs-Datensatz. Aufgrund des Trainings-Datensatzes konnten mittels TSSA 4 Subgruppen identifiziert werden, deren Hüftfraktur-Risiko bei einem Follow-up von im Mittel 6,5 Jahren bei 19%, 9%, 4% und 1% lag. Die Einteilung in die Subgruppen erfolgte aufgrund der Bewertung der BMD des Ward'schen Dreiecks sowie des Oberschenkelhalses und nach dem Alter. Diese Ergebnisse konnten mittels des Validierungs-Datensatzes reproduziert werden, was die Sinnhaftigkeit der Klassifizierungregeln in einem klinischen Setting bestätigte. Mittels TSSA war eine sinnvolle, aussagekräftige und reproduzierbare Identifikation von prognostischen Subgruppen, die auf dem Alter und den BMD-Werten beruhen, möglich. In this paper we studied the risk of hip fracture for post-menopausal women by classifying women into different subgroups based on their risk of hip fracture. The subgroups were generated such that all the women in a particular subgroup had relatively similar risk while women belonging to two different subgroups had rather different risks of hip fracture. We used the Tree Structured

  16. Survival analysis in the presence of competing risks.

    Science.gov (United States)

    Zhang, Zhongheng

    2017-02-01

    Survival analysis in the presence of competing risks imposes additional challenges for clinical investigators in that hazard function (the rate) has no one-to-one link to the cumulative incidence function (CIF, the risk). CIF is of particular interest and can be estimated non-parametrically with the use cuminc() function. This function also allows for group comparison and visualization of estimated CIF. The effect of covariates on cause-specific hazard can be explored using conventional Cox proportional hazard model by treating competing events as censoring. However, the effect on hazard cannot be directly linked to the effect on CIF because there is no one-to-one correspondence between hazard and cumulative incidence. Fine-Gray model directly models the covariate effect on CIF and it reports subdistribution hazard ratio (SHR). However, SHR only provide information on the ordering of CIF curves at different levels of covariates, it has no practical interpretation as HR in the absence of competing risks. Fine-Gray model can be fit with crr() function shipped with the cmprsk package. Time-varying covariates are allowed in the crr() function, which is specified by cov2 and tf arguments. Predictions and visualization of CIF for subjects with given covariate values are allowed for crr object. Alternatively, competing risk models can be fit with riskRegression package by employing different link functions between covariates and outcomes. The assumption of proportionality can be checked by testing statistical significance of interaction terms involving failure time. Schoenfeld residuals provide another way to check model assumption.

  17. Survival analysis with clustered observations of orthodontic brackets.

    Science.gov (United States)

    Petracci, Elisabetta; Farella, Mauro; Galeone, Carlotta; Albano, Alessandra; Ferraroni, Monica; Decarli, Adriano

    2009-12-10

    Failures in the bonding of dental bracket are a big concern for orthodontists. Clinical experience suggests that some patients are more prone than others to experience failures. Therefore, it can be expected that in statistical analysis of orthodontic bracket failures, the usual assumption of independence between the observations is violated. An approach to overcome this problem is to apply the frailty model, in which the association between failure times is modelled with a random-effect term (i.e. frailty). We postulated that brackets of the same subject share the same frailty, that is, a latent common group effect, due to some unknown or unobserved covariates.The aim of this study was to investigate possible risk factors related to bracket failure using Cox proportional hazards model with a shared frailty term and to compare the results with those obtained using a basic Cox proportional hazards model.Survival data for 1677 brackets were obtained from a cohort of 54 females (mean age +/- SD: 13.3+/-4.8 yrs) and 46 males (mean age +/-SD: 13.1+/-3.8 yrs) over a eight-year period. Age, gender, vertical craniofacial morphology and anatomical location of brackets were entered into Cox models as covariates. The findings indicated that bracket failure was significantly affected by tooth position within the dental arch, with the highest failure risk in maxillary posterior region. Age, gender and vertical craniofacial morphology did not affect bracket failure. A Cox proportional hazards model with a shared frailty term represents a useful approach for modelling orthodontic bracket failures. Copyright (c) 2009 John Wiley & Sons, Ltd.

  18. SURVIVAL ANALYSIS OF CANCER CASES FROM QIDONG CANCER REGISTRY

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-guo; Sankaranarayanan R; SHEN Zhuo-cai; Black RJ; YAO Hong-yu; LI Wen-guang; Parkin DM

    1999-01-01

    Objective: 16,922 patients with cancers from 15 sites of Qidong population-based cancer registry in the period of 1982-1991 were analyzed for evaluation of cancer survival as well as different cancer control measures.Methods: Observed survival rate (OS) was computed by the Kaplan-Meier method using EGRET statistical software package. Relative survival (RS) which is the ratio of the OS to the expected rate was calculated by using Qidong life table with respect to sex, age and calendar period of observation. Results: The five-year OS for the 5 leading sites of cancers, liver, stomach, lung,oesophagus, and rectum were 1.8%, 11.6%, 3.0% 3.3%,and 19.9%, respectively. The five-year RS for the 5 sites were 1.9%, 14.0%, 3.6%, 4.2%, and 23.7%, respectively,in which, 1.7%, 14.8%, 3.4%, 4.2%, and 26.0% for males, and 2.7%, 12.7%, 4.1%, 4.0%, and 22.0% for females, respectively. Female patients with breast cancer and cervix cancer had 5-year RS of 54.6% and 33.0%.Conclusion: Cancer survival rates for all sites are poor,in which that of the liver is the lowest, while that of the breast, the highest. The survivals of cancers for all sites,especially for breast, cervix, and leukemia are seen to be lower than those of European countries except for oesophagus, pancreas and lung cancer which do not achieve improved survival both in developing and developed countries. There will be a long way to improve the total cancer survival, as well as the cancer treatment in the developing countries.

  19. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Hakon

    2016-06-14

    This work embeds a multilevel Monte Carlo sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF) in the setting of finite dimensional signal evolution and noisy discrete-time observations. The signal dynamics is assumed to be governed by a stochastic differential equation (SDE), and a hierarchy of time grids is introduced for multilevel numerical integration of that SDE. The resulting multilevel EnKF is proved to asymptotically outperform EnKF in terms of computational cost versus approximation accuracy. The theoretical results are illustrated numerically.

  20. A New Rational-based Optimal Design Strategy of Ship Structure Based on Multi-level Analysis and Super-element Modeling Method

    Institute of Scientific and Technical Information of China (English)

    Li Sun; Deyu Wang

    2011-01-01

    A new multi-level analysis method of introducing the super-element modeling method,derived from the multi-level analysis method first proposed by O.F.Hughes,has been proposed in this paper to solve the problem of high time cost in adopting a rational-based optimal design method for ship structural design.Furthermore,the method was verified by its effective application in optimization of the mid-ship section of a container ship.A full 3-D FEM model of a ship,suffering static and quasi-static loads,was used as the analyzing object for evaluating the structural performance of the mid-ship module,including static strength and buckling performance.Research results reveal that this new method could substantially reduce the computational cost of the rational-based optimization problem without decreasing its accuracy,which increases the feasibility and economic efficiency of using a rational-based optimal design method in ship structural design.

  1. Survival analysis of cervical cancer using stratified Cox regression

    Science.gov (United States)

    Purnami, S. W.; Inayati, K. D.; Sari, N. W. Wulan; Chosuvivatwong, V.; Sriplung, H.

    2016-04-01

    Cervical cancer is one of the mostly widely cancer cause of the women death in the world including Indonesia. Most cervical cancer patients come to the hospital already in an advanced stadium. As a result, the treatment of cervical cancer becomes more difficult and even can increase the death's risk. One of parameter that can be used to assess successfully of treatment is the probability of survival. This study raises the issue of cervical cancer survival patients at Dr. Soetomo Hospital using stratified Cox regression based on six factors such as age, stadium, treatment initiation, companion disease, complication, and anemia. Stratified Cox model is used because there is one independent variable that does not satisfy the proportional hazards assumption that is stadium. The results of the stratified Cox model show that the complication variable is significant factor which influent survival probability of cervical cancer patient. The obtained hazard ratio is 7.35. It means that cervical cancer patient who has complication is at risk of dying 7.35 times greater than patient who did not has complication. While the adjusted survival curves showed that stadium IV had the lowest probability of survival.

  2. Applying survival analysis on the Cepheid period-luminosity relation at 70 μm

    Science.gov (United States)

    Ngeow, Chow-Choong

    2017-09-01

    The survival analysis is a type of statistical technique to deal with data that has upper or lower limits. In this work, I demonstrate an example of applying the survival analysis to re-derive the Cepheid period-luminosity relation at 70 μm, because about 2/3 of the currently available data only contains upper limits in flux.

  3. Assessing community-based conservation projects: A systematic review and multilevel analysis of attitudinal, behavioral, ecological, and economic outcomes

    Directory of Open Access Journals (Sweden)

    Brooks Jeremy

    2013-01-01

    Full Text Available Abstract Background Community-based conservation (CBC promotes the idea that long-term conservation success requires engaging with, and providing benefits for local communities. Though widespread, CBC projects are not always successful or free of controversy. With criticisms on all sides of the conservation debates, it is critical to have a better understanding of (1 whether CBC is an effective conservation tool, and (2 of the factors associated with the success or failure of CBC projects, and the scale at which these factors operate. Recent CBC reviews have typically examined only a single resource domain, have limited geographic scope, consider only one outcome, or ignore the nested nature of socioecological systems. To remedy these issues, we use a newly coded global comparative database of CBC projects identified by systematic review to evaluate success in four outcome domains (attitudes, behaviors, ecological, economic and explore synergies and tradeoffs among these outcomes. We test hypotheses about how features of the national context (H-NC, project design (H-PD, and local community characteristics (H-CC affect these four measures of success. Methods To add to a sample of 62 projects that we used from previous systematic reviews, we systematically searched the conservation literature using six terms in four online databases. To increase the number of projects for each country in order to conduct a multilevel analysis, we also conducted a secondary search using the Advancing Conservation in a Social Context online library. We coded projects for 65 pieces of information. We conducted bivariate analyses using two-dimensional contingency tables and proportional odds logistic regression and conducted multivariate analyses by fitting reduced form proportional odds logistic regression models that were selected using a forward stepwise AIC approach. Results The primary and secondary searches produced 74 new projects to go along with the 62

  4. Testing Group Mean Differences of Latent Variables in Multilevel Data Using Multiple-Group Multilevel CFA and Multilevel MIMIC Modeling.

    Science.gov (United States)

    Kim, Eun Sook; Cao, Chunhua

    2015-01-01

    Considering that group comparisons are common in social science, we examined two latent group mean testing methods when groups of interest were either at the between or within level of multilevel data: multiple-group multilevel confirmatory factor analysis (MG ML CFA) and multilevel multiple-indicators multiple-causes modeling (ML MIMIC). The performance of these methods were investigated through three Monte Carlo studies. In Studies 1 and 2, either factor variances or residual variances were manipulated to be heterogeneous between groups. In Study 3, which focused on within-level multiple-group analysis, six different model specifications were considered depending on how to model the intra-class group correlation (i.e., correlation between random effect factors for groups within cluster). The results of simulations generally supported the adequacy of MG ML CFA and ML MIMIC for multiple-group analysis with multilevel data. The two methods did not show any notable difference in the latent group mean testing across three studies. Finally, a demonstration with real data and guidelines in selecting an appropriate approach to multilevel multiple-group analysis are provided.

  5. Multilevel analysis of systolic blood pressure and ACE gene I/D polymorphism in 438 Swedish families – a public health perspective

    Directory of Open Access Journals (Sweden)

    Råstam Lennart

    2006-03-01

    Full Text Available Abstract Background Individuals belonging to the same family share a number of genetic as well as environmental circumstances that may condition a common SBP level. Among the genetic factors, the angiotensin converting enzyme (ACE gene I/D polymorphism appears as a possible candidate as it might influence both SBP and the pharmacological effect of ACE inhibitors. We aimed to combine genetic epidemiology with public health ideas concerning life-course and multilevel epidemiology in order to understand the role of familial factors regarding individual SBP. Methods We applied multilevel regression analysis on 1926 individuals nested within 438 families from South Sweden. Modelling familial SBP variance as a function of age and use of ACE inhibitors we calculates a variance partition coefficient and the proportional change in familial SBP variance attributable to differences in ACE gene I/D polymorphism Results Our results suggest the existence of genetic or environmental circumstances that produce a considerable familial clustering of SBP, especially among individuals using ACE-inhibitors. However, ACE gene I/D polymorphism seems to play a minor role in this context. In addition, familial factors – genetic, environmental or their interaction – shape SBP among non-users of ACE inhibitors but their effect is expressed later in the life-course. Conclusion Strategies directed to prevent hypertension should be launched in younger rather than in older ages and both prevention of hypertension and its treatment with ACE inhibitors should be focused on families rather than on individuals.

  6. Survival analysis of the CEAwatch multicentre clustered randomized trial

    NARCIS (Netherlands)

    Verberne, C. J.; Zhan, Z.; van den Heuvel, E. R.; Oppers, F.; de Jong, A. M.; Grossmann, Irene; Klaase, J. M.; de Bock, G. H.; Wiggers, T.

    2017-01-01

    Background: The CEAwatch randomized trial showed that follow-up with intensive carcinoembryonic antigen (CEA) monitoring (CEAwatch protocol) was better than care as usual (CAU) for early postoperative detection of colorectal cancer recurrence. The aim of this study was to calculate overall survival

  7. Survival Analysis of Breast Cancer Subtypes in Spinal Metastases Patients

    DEFF Research Database (Denmark)

    Wang, Miao; Jensen, Anders Bonde; Morgen, Soeren Smith

    2014-01-01

    STUDY DESIGN: We conducted a retrospective cohort study of 151 patients with breast cancer spinal metastases. OBJECTIVE: To investigate the influence of breast cancer subtypes on survival duration of patients with breast cancer spinal metastases, and to aid spine surgeons in selecting treatments ...

  8. Statistical Survival Analysis of Fish and Wildlife Tagging Studies; SURPH.1 Manual - Analysis of Release-Recapture Data for Survival Studies, 1994 Technical Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Steven G.; Skalski, John R.; Schelechte, J. Warren [Univ. of Washington, Seattle, WA (United States). Center for Quantitative Science

    1994-12-01

    Program SURPH is the culmination of several years of research to develop a comprehensive computer program to analyze survival studies of fish and wildlife populations. Development of this software was motivated by the advent of the PIT-tag (Passive Integrated Transponder) technology that permits the detection of salmonid smolt as they pass through hydroelectric facilities on the Snake and Columbia Rivers in the Pacific Northwest. Repeated detections of individually tagged smolt and analysis of their capture-histories permits estimates of downriver survival probabilities. Eventual installation of detection facilities at adult fish ladders will also permit estimation of ocean survival and upstream survival of returning salmon using the statistical methods incorporated in SURPH.1. However, the utility of SURPH.1 far exceeds solely the analysis of salmonid tagging studies. Release-recapture and radiotelemetry studies from a wide range of terrestrial and aquatic species have been analyzed using SURPH.1 to estimate discrete time survival probabilities and investigate survival relationships. The interactive computing environment of SURPH.1 was specifically developed to allow researchers to investigate the relationship between survival and capture processes and environmental, experimental and individual-based covariates. Program SURPH.1 represents a significant advancement in the ability of ecologists to investigate the interplay between morphologic, genetic, environmental and anthropogenic factors on the survival of wild species. It is hoped that this better understanding of risk factors affecting survival will lead to greater appreciation of the intricacies of nature and to improvements in the management of wild resources. This technical report is an introduction to SURPH.1 and provides a user guide for both the UNIX and MS-Windows{reg_sign} applications of the SURPH software.

  9. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  10. Cross-national and multilevel correlates of partner violence: an analysis of data from population-based surveys.

    Science.gov (United States)

    Heise, Lori L; Kotsadam, Andreas

    2015-06-01

    On average, intimate partner violence affects nearly one in three women worldwide within their lifetime. But the distribution of partner violence is highly uneven, with a prevalence of less than 4% in the past 12 months in many high-income countries compared with at least 40% in some low-income settings. Little is known about the factors that drive the geographical distribution of partner violence or how macro-level factors might combine with individual-level factors to affect individual women's risk of intimate partner violence. We aimed to assess the role that women's status and other gender-related factors might have in defining levels of partner violence among settings. We compiled data for the 12 month prevalence of partner violence from 66 surveys (88 survey years) from 44 countries, representing 481 205 women between Jan 1, 2000, and Apr 17, 2013. Only surveys with comparable questions and state-of-the-art methods to ensure safety and encourage violence disclosure were used. With linear and quantile regression, we examined associations between macro-level measures of socioeconomic development, women's status, gender inequality, and gender-related norms and the prevalence of current partner violence at a population level. Multilevel modelling and tests for interaction were used to explore whether and how macro-level factors affect individual-level risk. The outcome for this analysis was the population prevalence of current partner violence, defined as the percentage of ever-partnered women (excluding widows without a current partner), aged from 15 years to 49 years who were victims of at least one act of physical or sexual violence within the past 12 months. Gender-related factors at the national and subnational level help to predict the population prevalence of physical and sexual partner violence within the past 12 months. Especially predictive of the geographical distribution of partner violence are norms related to male authority over female behaviour

  11. The Effect of Perceived Instructional Effectiveness on Student Loyalty: A Multilevel Structural Equation Model

    Science.gov (United States)

    Simsek, Gulhayat Golbasi; Noyan, Fatma

    2009-01-01

    Social sciences research often entails the analysis of data with a multilevel structure. An example of multilevel data is containing measurement on university students nested within instructors. This paper concentrates on multilevel analysis of structural equation modeling with educational data. Data used in this study were gathered from 17647…

  12. Analysis and implementation of power management and control strategy for six-phase multilevel ac drive system in fault condition

    Directory of Open Access Journals (Sweden)

    Sanjeevikumar Padmanaban

    2016-03-01

    Full Text Available This research article exploits the power management algorithm in post-fault conditions for a six-phase (quad multilevel inverter. The drive circuit consists of four 2-level, three-phase voltage source inverter (VSI supplying a six-phase open-end windings motor or/impedance load, with circumstantial failure of one VSI investigated. A simplified level-shifted pulse-width modulation (PWM algorithm is developed to modulate each couple of three-phase VSI as 3-level output voltage generators in normal operation. The total power of the whole ac drive is shared equally among the four isolated DC sources. The developed post-fault algorithm is applied when there is a fault by one VSI and the load is fed from the remaining three healthy VSIs. In faulty conditions the multilevel outputs are reduced from 3-level to 2-level, but still the system propagates with degraded power. Numerical simulation modelling and experimental tests have been carried out with proposed post-fault control algorithm with three-phase open-end (asymmetrical induction motor/R-L impedance load. A complete set of simulation and experimental results provided in this paper shows close agreement with the developed theoretical background.

  13. Nonparametric Bayesian Inference for Mean Residual Life Functions in Survival Analysis

    OpenAIRE

    Poynor, Valerie; Kottas, Athanasios

    2014-01-01

    Modeling and inference for survival analysis problems typically revolves around different functions related to the survival distribution. Here, we focus on the mean residual life function which provides the expected remaining lifetime given that a subject has survived (i.e., is event-free) up to a particular time. This function is of direct interest in reliability, medical, and actuarial fields. In addition to its practical interpretation, the mean residual life function characterizes the sur...

  14. Multilevel analysis of self-perception in oral health and associated factors in Southern Brazilian adults: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Marilisa Carneiro Leão Gabardo

    2015-01-01

    Full Text Available The aim of this study was to evaluate the association between individual and contextual variables related to self-perception in oral health among residents in the municipality of São Leopoldo, Rio Grande do Sul State, Brazil. The cross-sectional design involved 1,100 adults in 38 census tracts. The self-perception was evaluated using the Oral Health Impact Profile (OHIP-14 tool. A logistic multilevel analysis was performed. The multivariate analysis revealed that those who are of the female gender, older, with lower scores of quality of life and less social support, with poor healthy eating habits, smokers and those living in low-income census tracts presented higher odds of reporting worse oral health self-perception (OHIP-1. We concluded that individual and contextual variables are associated with oral health self-perception. This is essential information for planning health services wishing to meet the health needs of the population.

  15. Control of Cascaded Multilevel Inverters

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Abstract-A new type of multilevel inverter is introduced which is created by cascading two three-phase three-level inverters using the load connection, but requires only one DC voltage source. This new inverter can operateas a seven-level inverter and naturally splits the power conversion into a higher-voltage lower-frequency inverter and a lower-voltage higher-fre-quency inverter. This type of system presents particular advantages to Naval ship propulsion systems which rely on high power quality, survivable drives. New control methods are described involving both joint and separate control of the individual three-level inverters. Simulation resuits demonstrate the effectiveness of both controls. A laboratory set-up at the Naval Surface Warfare Center power electronics laboratory was used to validate the proposed joint-inverter control. Due to the effect of compounding levels in the cascaded inverter, a high number of levels are available resulting in a voltage THD of 9% (without filtering). Index Terms-Cascaded inverter, multilevel inverter, three-level inverter.

  16. Advanced Online Survival Analysis Tool for Predictive Modelling in Clinical Data Science.

    Science.gov (United States)

    Montes-Torres, Julio; Subirats, José Luis; Ribelles, Nuria; Urda, Daniel; Franco, Leonardo; Alba, Emilio; Jerez, José Manuel

    2016-01-01

    One of the prevailing applications of machine learning is the use of predictive modelling in clinical survival analysis. In this work, we present our view of the current situation of computer tools for survival analysis, stressing the need of transferring the latest results in the field of machine learning to biomedical researchers. We propose a web based software for survival analysis called OSA (Online Survival Analysis), which has been developed as an open access and user friendly option to obtain discrete time, predictive survival models at individual level using machine learning techniques, and to perform standard survival analysis. OSA employs an Artificial Neural Network (ANN) based method to produce the predictive survival models. Additionally, the software can easily generate survival and hazard curves with multiple options to personalise the plots, obtain contingency tables from the uploaded data to perform different tests, and fit a Cox regression model from a number of predictor variables. In the Materials and Methods section, we depict the general architecture of the application and introduce the mathematical background of each of the implemented methods. The study concludes with examples of use showing the results obtained with public datasets.

  17. Preliminary survivability analysis of manned spacecraft following orbital debris penetration

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; HAN ZengYao; LIMing; ZHENG ShiGui

    2009-01-01

    Meteoroid and orbital debris (M/OD) may cause severe damages or even catastrophic failures for long-term manned spacecrafts in orbit due to the hypervelocity impact (HVI) destruction. It is essential to quantitatively assess the M/OD risk of manned spacecraft, in this paper, the catastrophic failure as-sessment function is successfully integrated into the Meteoroid & Orbital Debris Assessment and Op-timization System Tools (MODAOST), which is the M/OD risk assessment system developed by China Academy of Space Technology. The survivability assessment for the US Lab by MODAOST was con-sistent with that of the Manned Spacecraft Crew Survivability computer code (MSCSurv). Meanwhile,the simulation process showed that this function was more effective than MSCSurv for the application of the standard methodology of M/OD risk assessment instead of the Monte Carlo model. This function expands the ability of MODAOST in predicting the survivability of the typical catastrophic failure modes such as crew hypoxia and the critical cracking.

  18. Preliminary survivability analysis of manned spacecraft following orbital debris penetration

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Meteoroid and orbital debris(M/OD) may cause severe damages or even catastrophic failures for long-term manned spacecrafts in orbit due to the hypervelocity impact(HVI) destruction.It is essential to quantitatively assess the M/OD risk of manned spacecraft.In this paper,the catastrophic failure as-sessment function is successfully integrated into the Meteoroid & Orbital Debris Assessment and Op-timization System Tools(MODAOST),which is the M/OD risk assessment system developed by China Academy of Space Technology.The survivability assessment for the US Lab by MODAOST was con-sistent with that of the Manned Spacecraft Crew Survivability computer code(MSCSurv).Meanwhile,the simulation process showed that this function was more effective than MSCSurv for the application of the standard methodology of M/OD risk assessment instead of the Monte Carlo model.This function expands the ability of MODAOST in predicting the survivability of the typical catastrophic failure modes such as crew hypoxia and the critical cracking.

  19. Epidemiology and Survival Analysis of Jordanian Female Breast Cancer Patients Diagnosed from 1997 to 2002

    Directory of Open Access Journals (Sweden)

    Ghazi Sharkas

    2011-04-01

    Full Text Available Background: Breast cancer is the most common cancer among Jordanian women, yet survival data are scarce. This study aims to assess the observed five-year survival rate of breast cancer in Jordan from 1997 to 2002 and to determine factors that may influence survival. Methods: Data were obtained from the Jordan Cancer Registry (JCR, which is a population-based registry. From 1997-2002, 2121 patients diagnosed with breast cancer were registered in JCR. Relevant data were collected from JCR files, hospital medical records and histopathology reports. Patient's status, whether alive or dead, wasascertained from the Department of Civil Status using patients’ national numbers (ID. Statistical analysis was carried out using SPSS (version 10. Survival probabilities by age, morphology, grade, stage and other relevant variables were obtained with the Kaplan Meier method. Results: The overall five-year survival for breast cancer in Jordan, regardless of the stage or grade was 64.2%, meanwhile it was 58% in the group aged less than 30 years. The best survival was in the age group 40-49 years (69.3%. The survival for adenocarcinoma was 57.4% and for medullary carcinoma, it was 82%. The survival rate approximated 73.8% for well-differentiated, 55.6% for anaplastic, and 58% for poorly differentiated cancers. The five-year survival rate was 82.7% for stage I, 72.2% for stage II, 58.7% for stage III, and 34.6% for stage IV cancers.Conclusion: According to univariate analysis, stage, grade, age and laterality of breast cancer significantly influenced cancer survival. Cox regression analysis revealed that stage, grade and age factors correlated with prognosis, while laterality showed no significant effect on survival. Results demonstrated that overall survival was relatively poor. We hypothesized that this was due to low levels of awareness and lack of screening programs.

  20. Mediation analysis of the relationship between institutional research activity and patient survival

    DEFF Research Database (Denmark)

    Rochon, Justine; du Bois, Andreas; Lange, Theis

    2014-01-01

    BACKGROUND: Recent studies have suggested that patients treated in research-active institutions have better outcomes than patients treated in research-inactive institutions. However, little attention has been paid to explaining such effects, probably because techniques for mediation analysis...... existing so far have not been applicable to survival data. METHODS: We investigated the underlying mechanisms using a recently developed method for mediation analysis of survival data. Our analysis of the effect of research activity on patient survival was based on 352 patients who had been diagnosed...... as potential mediators of the effect of hospital research activity on patient survival. RESULTS: The 219 patients treated in hospitals participating in clinical trials had more complete surgical debulking, were more likely to receive the recommended platinum-taxane combination, and had better survival than...

  1. A Multivariate Model for the Meta-Analysis of Study Level Survival Data at Multiple Times

    Science.gov (United States)

    Jackson, Dan; Rollins, Katie; Coughlin, Patrick

    2014-01-01

    Motivated by our meta-analytic dataset involving survival rates after treatment for critical leg ischemia, we develop and apply a new multivariate model for the meta-analysis of study level survival data at multiple times. Our data set involves 50 studies that provide mortality rates at up to seven time points, which we model simultaneously, and…

  2. Using Survival Analysis to Describe Developmental Achievements of Early Intervention Recipients at Kindergarten

    Science.gov (United States)

    Scarborough, Anita A.; Hebbeler, Kathleen M.; Spiker, Donna; Simeonsson, Rune J.

    2011-01-01

    Survival analysis was used to document the developmental achievements of 2298 kindergarten children who participated in the National Early Intervention Longitudinal Study, a study that followed children from entry to Part C early intervention (EI) through kindergarten. Survival functions were produced depicting the percentage of children at…

  3. Survival analysis using S analysis of time-to-event data

    CERN Document Server

    Tableman, Mara

    2003-01-01

    Survival Analysis Using S: Analysis of Time-to-Event Data is designed as a text for a one-semester or one-quarter course in survival analysis for upper-level or graduate students in statistics, biostatistics, and epidemiology. Prerequisites are a standard pre-calculus first course in probability and statistics, and a course in applied linear regression models. No prior knowledge of S or R is assumed. A wide choice of exercises is included, some intended for more advanced students with a first course in mathematical statistics. The authors emphasize parametric log-linear models, while also detailing nonparametric procedures along with model building and data diagnostics. Medical and public health researchers will find the discussion of cut point analysis with bootstrap validation, competing risks and the cumulative incidence estimator, and the analysis of left-truncated and right-censored data invaluable. The bootstrap procedure checks robustness of cut point analysis and determines cut point(s). In a chapter ...

  4. Multilevel- marketing v České republice

    OpenAIRE

    Prudičová, Petra

    2009-01-01

    Graduation Theses concerns an analysis and evaluation, of how a multi-level marketing, functions in the Czech Republic. Explaining its ideals and principals, while it theoretically applies on a specific company, which is involved with multi-level marketing. The target is to introduce such system in an objective way and evaluate it in practice.

  5. Multilevel- marketing v České republice

    OpenAIRE

    Prudičová, Petra

    2009-01-01

    Graduation Theses concerns an analysis and evaluation, of how a multi-level marketing, functions in the Czech Republic. Explaining its ideals and principals, while it theoretically applies on a specific company, which is involved with multi-level marketing. The target is to introduce such system in an objective way and evaluate it in practice.

  6. Thermal analysis of multilevel grid side converters for 10 MW wind turbines under Low Voltage Ride Through

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede; Liserre, Marco

    2011-01-01

    As the power level of a single wind turbine is continuously pushed up even to 7 MW, the wind power generation system are required to be more reliable, and able to withstand extreme grid disturbances. Moreover, it is becoming a need that the wind power generation system should be more active......-scale power converters, especially during grid faults may compromise the reliability performance and further increase the cost of the system. In this paper, three promising grid side multilevel converter topologies for the next generation 10 MW wind turbines are proposed and basically designed as case study....... The operation status, as well as loss and thermal distributions of power devices are investigated, simulated and compared aimed at various Low Voltage Ride Through (LVRT) conditions. It is found that the all of the proposed converter topologies will suffer from higher junction temperature in some heavy loaded...

  7. The Pattern of Variation between Diarrhea and Malaria Coexistence with Corresponding Risk Factors in, Chikhwawa, Malawi: A Bivariate Multilevel Analysis

    Directory of Open Access Journals (Sweden)

    Salule Masangwi

    2015-07-01

    Full Text Available Developing countries face a huge burden of infectious diseases, a number of which co-exist. This paper estimates the pattern and variation of malaria and diarrhea coexistence in Chikhwawa, a district in Southern Malawi using bivariate multilevel modelling with Bayesian estimation. A probit link was employed to examine hierarchically built data from a survey of individuals (n = 6,727 nested within households (n = 1,380 nested within communities (n = 33. Results show significant malaria [ ] and diarrhea [ ] variations with a strong correlation between them [ ] at household level. There are significant malaria [ ] and diarrhea [   ] variations at community level but with a small correlation [ ] between them. There is also significant correlation between malaria and diarrhea at individual level [ 0.241]. These results suggest a close association between reported malaria-like illness and diarrheal illness especially at household and individual levels in Southern Malawi.

  8. A multilevel analysis of social ties and social cohesion among Latinos and their neighborhoods: results from Chicago.

    Science.gov (United States)

    Almeida, Joanna; Kawachi, Ichiro; Molnar, Beth E; Subramanian, S V

    2009-09-01

    Research suggests that, among Latinos, there are health benefits associated with living in a neighborhood populated with coethnics. While social networks and social cohesion are the proposed explanation for the salubrious effect and are assumed to be characteristics of Latino immigrant enclaves, evidence for this is limited. We used multilevel regression to test the relative contribution of individual race/ethnicity and neighborhood concentration of Mexican Americans as predictors of social networks and social cohesion. After accounting for personal characteristics, we found a negative association between neighborhood concentration of Mexican Americans and social cohesion. Among Latinos, living in a neighborhood with increased coethnics was associated with increased social ties. Compared to non-Latino whites, Mexican Americans reported more social ties but lower social cohesion. Contrary to the assumption that Mexican immigrant enclaves beget social cohesion, we did not find this to be true in Chicago neighborhoods.

  9. Perceptions of community, social capital, and how they affect self-reported health: a multilevel analysis.

    Science.gov (United States)

    Dziadkowiec, O; Meissen, G J; Merkle, E C

    2017-07-14

    The link between social capital and self-reported health has been widely explored. On the other hand, we know less about the relationship between social capital, community socioeconomic characteristics, and non-social capital-related individual differences, and about their impact on self-reported health in community settings. Cross-sectional study design with a proportional sample of 7965 individuals from 20 US communities were analyzed using multilevel linear regression models, where individuals were nested within communities. The response rates ranged from 13.5% to 25.4%. Findings suggest that perceptions of the community and individual level socioeconomic characteristics were stronger predictors of self-reported health than were social capital or community socioeconomic characteristics. Policy initiatives aimed at increasing social capital should first assess community member's perceptions of their communities to uncover potential assets to help increase social capital. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  10. A multilevel structural equation modeling analysis of vulnerabilities and resilience resources influencing affective adaptation to chronic pain.

    Science.gov (United States)

    Sturgeon, John A; Zautra, Alex J; Arewasikporn, Anne

    2014-02-01

    The processes of individual adaptation to chronic pain are complex and occur across multiple domains. We examined the social, cognitive, and affective context of daily pain adaptation in individuals with fibromyalgia and osteoarthritis. By using a sample of 260 women with fibromyalgia or osteoarthritis, we examined the contributions of pain catastrophizing, negative interpersonal events, and positive interpersonal events to daily negative and positive affect across 30days of daily diary data. Individual differences and daily fluctuations in predictor variables were estimated simultaneously by utilizing multilevel structural equation modeling techniques. The relationships between pain and negative and positive affect were mediated by stable and day-to-day levels of pain catastrophizing as well as day-to-day positive interpersonal events, but not negative interpersonal events. There were significant and independent contributions of pain catastrophizing and positive interpersonal events to adaptation to pain and pain-related affective dysregulation. These effects occur both between persons and within a person's everyday life.

  11. Analysis of breath samples for lung cancer survival

    Energy Technology Data Exchange (ETDEWEB)

    Schmekel, Birgitta [Division of of Clinical Physiology, County Council of Östergötland, Linköping (Sweden); Clinical Physiology, Department of Medicine and Health, Faculty of Health Sciences, Linköping University, Linköping (Sweden); Winquist, Fredrik, E-mail: frw@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, Linköping SE-581 83 (Sweden); Vikström, Anders [Department of Pulmonary Medicine, University hospital of Linköping, County Council of Östergötland, Linköping (Sweden)

    2014-08-20

    Graphical abstract: Predictions of survival days for lung cancer patients. - Highlights: • Analyses of exhaled air offer a large diagnostic potential. • Patientswith diagnosed lung cancer were studied using an electronic nose. • Excellent predictions and stable models of survival day were obtained. • Consecutive measurements were very important. - Abstract: Analyses of exhaled air by means of electronic noses offer a large diagnostic potential. Such analyses are non-invasive; samples can also be easily obtained from severely ill patients and repeated within short intervals. Lung cancer is the most deadly malignant tumor worldwide, and monitoring of lung cancer progression is of great importance and may help to decide best therapy. In this report, twenty-two patients with diagnosed lung cancer and ten healthy volunteers were studied using breath samples collected several times at certain intervals and analysed by an electronic nose. The samples were divided into three sub-groups; group d for survivor less than one year, group s for survivor more than a year and group h for the healthy volunteers. Prediction models based on partial least square and artificial neural nets could not classify the collected groups d, s and h, but separated well group d from group h. Using artificial neural net, group d could be separated from group s. Excellent predictions and stable models of survival day for group d were obtained, both based on partial least square and artificial neural nets, with correlation coefficients 0.981 and 0.985, respectively. Finally, the importance of consecutive measurements was shown.

  12. Multi-Level Analysis of the Determinants of Receipt of Clinical Preventive Services Among Reproductive-Age Women

    Science.gov (United States)

    McCall-Hosenfeld, Jennifer S.; Weisman, Carol S.; Camacho, Fabian; Hillemeier, Marianne M.; Chuang, Cynthia H.

    2012-01-01

    Background We investigate the impact of individual- and county-level contextual variables on women’s receipt of a comprehensive panel of preventive services in a region that includes both urban and rural communities. Methods Outcome variables were: a screening and vaccination index (a count of Papanicolaou test, blood pressure check, lipid panel, sexually transmitted infections or HIV test, and influenza vaccination received in the past 2 years) and a preventive counseling index (a count of topics discussed in the past 2 years: smoking and tobacco, alcohol or drugs, violence and safety, pregnancy planning or contraception, diet/nutrition, and sexually transmitted infections). Contextual covariates from the Area Resource File (2004-2005) were appended to prospective survey data from the Central Pennsylvania Women’s Health Study. Individual-level variables included predisposing, enabling, and need-based measures. Contextual variables included community characteristics and healthcare resources, including a measure of primary care physician density specifically designed for this study of women’s preventive care. Multi-level analyses were performed. Results We found low overall use of preventive services. In multi-level models, individual-level factors predicted receipt of both screening and vaccinations and counseling services; significant predictors differed for each index. One contextual variable (primary care physician density) predicted receipt of screenings and vaccinations. Conclusions Women’s receipt of preventive services was determined primarily by individual-level variables. Different variables predicted receipt of screening and vaccination versus counseling services. A contextual measure, primary care physician density, predicted receipt of preventive screenings and vaccinations. Individual variability in women’s receipt of counseling services is largely explained by psychosocial factors and seeing an obstetrician-gynecologist. PMID:22269668

  13. Small Convenience Stores and the Local Food Environment: An Analysis of Resident Shopping Behavior Using Multilevel Modeling.

    Science.gov (United States)

    Ruff, Ryan Richard; Akhund, Ali; Adjoian, Tamar

    2016-01-01

    Local food environments can influence the diet and health of individuals through food availability, proximity to retail stores, pricing, and promotion. This study focused on how small convenience stores, known in New York City as bodegas, influence resident shopping behavior and the food environment. Using a cross-sectional design, 171 bodegas and 2118 shoppers were sampled. Small convenience stores in New York City. Any bodega shopper aged 18+ who purchased food or beverage from a participating store. Data collection consisted of a store assessment, a health and behavior survey given to exiting customers, and a bag check that recorded product information for all customer purchases. Descriptive statistics were generated for bodega store characteristics, shopper demographics, and purchase behavior. Multilevel models were used to assess the influence of product availability, placement, and advertising on consumer purchases of sugar-sweetened beverages (SSBs), water, and fruits and vegetables. Seventy-one percent of participants reported shopping at bodegas five or more times per week, and 35% reported purchasing all or most of their monthly food allotment at bodegas. Model results indicated that lower amounts of available fresh produce were significantly and independently associated with a higher likelihood of SSB purchases. A second, stratified multilevel model showed that the likelihood of purchasing an SSB increased with decreasing varieties of produce when produce was located at the front of the store. No significant effects were found for water placement and beverage advertising. Small convenience stores in New York City are an easily accessible source of foods and beverages. Bodegas may be suitable for interventions designed to improve food choice and diet.

  14. Life satisfaction in the new country: a multilevel longitudinal analysis of effects of culture and 5-HTT allele frequency distribution in country of origin.

    Science.gov (United States)

    Kashima, Emiko S; Kent, Stephen; Kashima, Yoshihisa

    2015-01-01

    Life satisfaction of migrants to Australia from 17 countries, assessed at 4-5 months, 16-17 months and 3½ years after arrival, was analyzed with a longitudinal, multilevel analysis. The results indicated that migrants were more satisfied, if the national average life satisfaction was higher in their country of origin, after adjustment for individual-level income, age, and sex and a linear temporal trend. Simultaneously, the migrants were also happier if people in their country of origin had a higher frequency of 5-HTT long allele, a genotype known to be associated with resilience under life stresses. These two relationships were independent, suggesting that both culture and gene matter in international transitions.

  15. Students’ Perspective On The Impact Of The Title III Program On Doctoral And Professional Programs At Minority Serving Institutions: An Analysis Using A Multilevel Rasch Rating Scale Model

    Directory of Open Access Journals (Sweden)

    Aloyce R. Kaliba

    2012-12-01

    Full Text Available We assessed the impact of Part B, section 326 of the Title III program using data from three historically Black Universities. The Title III program aims at strengthening the resource capacity of Historically Black Colleges and Universities (HBCUs with eligible doctoral and professional programs. The lack of documented quantitative impact contributes to skepticism regarding program efficacy. A web-based survey instrument was used to collect data from students across five domains: research and instruction; technology development; facilities improvement; student financial assistance; and student services. A multilevel Rasch Rating Scale Model (ARSM was utilized for data analysis. The students indicated that the program has intermediate to high impact on research and instruction and low impact on tutorial and counseling services and outreach programs.

  16. Propensity score weighting with multilevel data.

    Science.gov (United States)

    Li, Fan; Zaslavsky, Alan M; Landrum, Mary Beth

    2013-08-30

    Propensity score methods are being increasingly used as a less parametric alternative to traditional regression to balance observed differences across groups in both descriptive and causal comparisons. Data collected in many disciplines often have analytically relevant multilevel or clustered structure. The propensity score, however, was developed and has been used primarily with unstructured data. We present and compare several propensity-score-weighted estimators for clustered data, including marginal, cluster-weighted, and doubly robust estimators. Using both analytical derivations and Monte Carlo simulations, we illustrate bias arising when the usual assumptions of propensity score analysis do not hold for multilevel data. We show that exploiting the multilevel structure, either parametrically or nonparametrically, in at least one stage of the propensity score analysis can greatly reduce these biases. We applied these methods to a study of racial disparities in breast cancer screening among beneficiaries of Medicare health plans.

  17. The association between the physical environment and the well-being of older people in residential care facilities: A multilevel analysis.

    Science.gov (United States)

    Nordin, Susanna; McKee, Kevin; Wijk, Helle; Elf, Marie

    2017-06-06

    To investigate the associations between the quality of the physical environment and the psychological and social well-being of older people living in residential care facilities. Many older people in care facilities have cognitive and physical frailties and are at risk of experiencing low levels of well-being. High-quality physical environments can support older people as frailty increases and promote their well-being. Although the importance of the physical environment for residents' well-being is recognized, more research is needed. A cross-sectional survey of 20 care facilities from each of which 10 residents were sampled. As the individual resident data were nested in the facilities, a multilevel analysis was conducted. Data were collected during 2013 and 2014. The care facilities were purposely sampled to ensure a high level of variation in their physical characteristics. Residents' demographic and health data were collected via medical records and interviews. Residents' well-being and perceived quality of care were assessed via questionnaires and interviews. Environmental quality was assessed with a structured observational instrument. Multilevel analysis indicated that cognitive support in the physical environment was associated with residents' social well-being, after controlling for independence and perceived care quality. However, no significant association was found between the physical environment and residents' psychological well-being. Our study demonstrates the role of the physical environment for enhancing the social well-being of frail older people. Professionals and practitioners involved in the design of care facilities have a responsibility to ensure that such facilities meet high-quality specifications. © 2017 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.

  18. Social capital, income inequality and self-rated health in Chita peninsula, Japan: a multilevel analysis of older people in 25 communities.

    Science.gov (United States)

    Ichida, Yukinobu; Kondo, Katsunori; Hirai, Hiroshi; Hanibuchi, Tomoya; Yoshikawa, Goshu; Murata, Chiyoe

    2009-08-01

    exhibit low trust levels, and that social capital mediates the relation between income inequality and health. This study is, to our knowledge, the first investigation of the linkage between social capital and health in Japan using multilevel analysis, and reports the first supported result of the relative income hypothesis in Japan. Additionally, the statistically significant linkage between the increased Gini coefficient and low trust observed in this study provides additional evidence to support the social cohesion and collective social pathway between income inequality and health.

  19. Parametric and semiparametric models with applications to reliability, survival analysis, and quality of life

    CERN Document Server

    Nikulin, M; Mesbah, M; Limnios, N

    2004-01-01

    Parametric and semiparametric models are tools with a wide range of applications to reliability, survival analysis, and quality of life. This self-contained volume examines these tools in survey articles written by experts currently working on the development and evaluation of models and methods. While a number of chapters deal with general theory, several explore more specific connections and recent results in "real-world" reliability theory, survival analysis, and related fields.

  20. Up-to-date and precise estimates of cancer patient survival: model-based period analysis.

    Science.gov (United States)

    Brenner, Hermann; Hakulinen, Timo

    2006-10-01

    Monitoring of progress in cancer patient survival by cancer registries should be as up-to-date as possible. Period analysis has been shown to provide more up-to-date survival estimates than do traditional methods of survival analysis. However, there is a trade-off between up-to-dateness and the precision of period estimates, in that increasing the up-to-dateness of survival estimates by restricting the analysis to a relatively short, recent time period, such as the most recent calendar year for which cancer registry data are available, goes along with a loss of precision. The authors propose a model-based approach to maximize the up-to-dateness of period estimates at minimal loss of precision. The approach is illustrated for monitoring of 5-year relative survival of patients diagnosed with one of 20 common forms of cancer in Finland between 1953 and 2002 by use of data from the nationwide Finnish Cancer Registry. It is shown that the model-based approach provides survival estimates that are as up-to-date as the most up-to-date conventional period estimates and at the same time much more precise than the latter. The modeling approach may further enhance the use of period analysis for deriving up-to-date cancer survival rates.

  1. A Novel Formal Analysis Method of Network Survivability Based on Stochastic Process Algebra

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guosheng; WANG Huiqiang; WANG Jian

    2007-01-01

    Stochastic process algebras have been proposed as compositional specification formalisms for performance models. A formal analysis method of survivable network was proposed based on stochastic process algebra, which incorporates formal modeling into performance analysis perfectly, and then various performance parameters of survivable network can be simultaneously obtained after formal modeling. The formal description with process expression to the survivable network system was carried out based on the simply introduced syntax and operational semantics of stochastic process algebra. Then PEPA workbench tool was used to obtain the probability of system's steady state availability and transient state availability. Simulation experiments show the effectiveness and feasibility of the developed method.

  2. Application of survival analysis methodology to the quantitative analysis of LC-MS proteomics data

    KAUST Repository

    Tekwe, C. D.

    2012-05-24

    MOTIVATION: Protein abundance in quantitative proteomics is often based on observed spectral features derived from liquid chromatography mass spectrometry (LC-MS) or LC-MS/MS experiments. Peak intensities are largely non-normal in distribution. Furthermore, LC-MS-based proteomics data frequently have large proportions of missing peak intensities due to censoring mechanisms on low-abundance spectral features. Recognizing that the observed peak intensities detected with the LC-MS method are all positive, skewed and often left-censored, we propose using survival methodology to carry out differential expression analysis of proteins. Various standard statistical techniques including non-parametric tests such as the Kolmogorov-Smirnov and Wilcoxon-Mann-Whitney rank sum tests, and the parametric survival model and accelerated failure time-model with log-normal, log-logistic and Weibull distributions were used to detect any differentially expressed proteins. The statistical operating characteristics of each method are explored using both real and simulated datasets. RESULTS: Survival methods generally have greater statistical power than standard differential expression methods when the proportion of missing protein level data is 5% or more. In particular, the AFT models we consider consistently achieve greater statistical power than standard testing procedures, with the discrepancy widening with increasing missingness in the proportions. AVAILABILITY: The testing procedures discussed in this article can all be performed using readily available software such as R. The R codes are provided as supplemental materials. CONTACT: ctekwe@stat.tamu.edu.

  3. Societal characteristics and health in the former communist countries of Central and Eastern Europe and the former Soviet Union: a multilevel analysis.

    Science.gov (United States)

    Bobak, Martin; Murphy, Mike; Rose, Richard; Marmot, Michael

    2007-11-01

    To examine whether, in former communist countries that have undergone profound social and economic transformation, health status is associated with income inequality and other societal characteristics, and whether this represents something more than the association of health status with individual socioeconomic circumstances. Multilevel analysis of cross-sectional data. 13 Countries from Central and Eastern Europe and the former Soviet Union. Population samples aged 18+ years (a total of 15 331 respondents). Poor self-rated health. There were marked differences among participating countries in rates of poor health (a greater than twofold difference between the countries with the highest and lowest rates of poor health), gross domestic product per capita adjusted for purchasing power parity (a greater than threefold difference), the Gini coefficient of income inequality (twofold difference), corruption index (twofold difference) and homicide rates (20-fold difference). Ecologically, the age- and sex-standardised prevalence of poor self-rated health correlated strongly with life expectancy at age 15 (r = -0.73). In multilevel analyses, societal (country-level) measures of income inequality were not associated with poor health. Corruption and gross domestic product per capita were associated with poor health after controlling for individuals' socioeconomic circumstances (education, household income, marital status and ownership of household items); the odds ratios were 1.15 (95% confidence interval 1.03 to 1.29) per 1 unit (on a 10-point scale) increase in the corruption index and 0.79 (95% confidence interval 0.68 to 0.93) per $5000 increase in gross domestic product per capita. The effects of gross domestic product and corruption were virtually identical in people whose household income was below and above the median. Societal measures of prosperity and corruption, but not income inequalities, were associated with health independently of individual

  4. A Multi-Level Bayesian Analysis of Racial Bias in Police Shootings at the County-Level in the United States, 2011-2014.

    Directory of Open Access Journals (Sweden)

    Cody T Ross

    Full Text Available A geographically-resolved, multi-level Bayesian model is used to analyze the data presented in the U.S. Police-Shooting Database (USPSD in order to investigate the extent of racial bias in the shooting of American civilians by police officers in recent years. In contrast to previous work that relied on the FBI's Supplemental Homicide Reports that were constructed from self-reported cases of police-involved homicide, this data set is less likely to be biased by police reporting practices. County-specific relative risk outcomes of being shot by police are estimated as a function of the interaction of: 1 whether suspects/civilians were armed or unarmed, and 2 the race/ethnicity of the suspects/civilians. The results provide evidence of a significant bias in the killing of unarmed black Americans relative to unarmed white Americans, in that the probability of being {black, unarmed, and shot by police} is about 3.49 times the probability of being {white, unarmed, and shot by police} on average. Furthermore, the results of multi-level modeling show that there exists significant heterogeneity across counties in the extent of racial bias in police shootings, with some counties showing relative risk ratios of 20 to 1 or more. Finally, analysis of police shooting data as a function of county-level predictors suggests that racial bias in police shootings is most likely to emerge in police departments in larger metropolitan counties with low median incomes and a sizable portion of black residents, especially when there is high financial inequality in that county. There is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates, meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates.

  5. A Multi-Level Bayesian Analysis of Racial Bias in Police Shootings at the County-Level in the United States, 2011-2014.

    Science.gov (United States)

    Ross, Cody T

    2015-01-01

    A geographically-resolved, multi-level Bayesian model is used to analyze the data presented in the U.S. Police-Shooting Database (USPSD) in order to investigate the extent of racial bias in the shooting of American civilians by police officers in recent years. In contrast to previous work that relied on the FBI's Supplemental Homicide Reports that were constructed from self-reported cases of police-involved homicide, this data set is less likely to be biased by police reporting practices. County-specific relative risk outcomes of being shot by police are estimated as a function of the interaction of: 1) whether suspects/civilians were armed or unarmed, and 2) the race/ethnicity of the suspects/civilians. The results provide evidence of a significant bias in the killing of unarmed black Americans relative to unarmed white Americans, in that the probability of being {black, unarmed, and shot by police} is about 3.49 times the probability of being {white, unarmed, and shot by police} on average. Furthermore, the results of multi-level modeling show that there exists significant heterogeneity across counties in the extent of racial bias in police shootings, with some counties showing relative risk ratios of 20 to 1 or more. Finally, analysis of police shooting data as a function of county-level predictors suggests that racial bias in police shootings is most likely to emerge in police departments in larger metropolitan counties with low median incomes and a sizable portion of black residents, especially when there is high financial inequality in that county. There is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates), meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates.

  6. Physical activity as a possible mechanism behind the relationship between green space and health: A multilevel analysis

    Directory of Open Access Journals (Sweden)

    Spreeuwenberg Peter

    2008-06-01

    Full Text Available Abstract Background The aim of this study was to investigate whether physical activity (in general, and more specifically, walking and cycling during leisure time and for commuting purposes, sports and gardening is an underlying mechanism in the relationship between the amount of green space in people's direct living environment and self-perceived health. To study this, we first investigated whether the amount of green space in the living environment is related to the level of physical activity. When an association between green space and physical activity was found, we analysed whether this could explain the relationship between green space and health. Methods The study includes 4.899 Dutch people who were interviewed about physical activity, self-perceived health and demographic and socioeconomic background. The amount of green space within a one-kilometre and a three-kilometre radius around the postal code coordinates was calculated for each individual. Multivariate multilevel analyses and multilevel logistic regression analyses were performed at two levels and with controls for socio-demographic characteristics and urbanicity. Results No relationship was found between the amount of green space in the living environment and whether or not people meet the Dutch public health recommendations for physical activity, sports and walking for commuting purposes. People with more green space in their living environment walked and cycled less often and fewer minutes during leisure time; people with more green space garden more often and spend more time on gardening. Furthermore, if people cycle for commuting purposes they spend more time on this if they live in a greener living environment. Whether or not people garden, the time spent on gardening and time spent on cycling for commuting purposes did not explain the relationship between green space and health. Conclusion Our study indicates that the amount of green space in the living environment is

  7. Individual and community level socioeconomic inequalities in contraceptive use in 10 Newly Independent States: a multilevel cross-sectional analysis

    Directory of Open Access Journals (Sweden)

    Janevic Teresa

    2012-11-01

    Full Text Available Abstract Introduction Little is known regarding the association between socioeconomic factors and contraceptive use in the Newly Independent States (NIS, countries that have experienced profound changes in reproductive health services during the transition from socialism to a market economy. Methods Using 2005–2006 data from Demographic Health Surveys (Armenia, Azerbaijan, and Moldova and Multiple Indicator Cluster Surveys (Belarus, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan, Ukraine, and Uzbekistan, we examined associations between individual and community socioeconomic status with current modern contraceptive use (MCU among N = 55,204 women aged 15–49 married or in a union. Individual socioeconomic status was measured using quintiles of wealth index and education level (higher than secondary school, secondary school or less. Community socioeconomic status was measured as the percentage of households in the poorest quintile of the nationals household wealth index (0%, 0–25%, or greater than 25%. We used multilevel logistic regression to estimate associations adjusted for age, number of children, urban/rural, and socioeconomic variables. Results MCU varied by country from 14% (in Azerbaijan to 62% (in Belarus. Overall, women living in the poorest communities were less likely than those in the richest to use modern contraceptives (adjusted odds ratio (aOR = 0.82, 95% Confidence Interval = 0.76, 0.89. Similarly, there was an increasing odds of MCU with increasing individual-level wealth. Women with a lower level of education also had lower odds of MCU than those with a higher level of education (aOR = .75, 95%CI = 0.71, 0.79. In country-specific analyses, community-level socioeconomic inequalities were apparent in 4 of 10 countries; in contrast, inequalities by individual-level wealth were apparent in 7 countries and by education in 8 countries. All countries in which community-level socioeconomic status was associated with

  8. Multilevel selection with kin and non-kin groups, experimental results with japanese quail (coturnix japonica)

    NARCIS (Netherlands)

    Muir, W.M.; Bijma, P.; schinckel, A.

    2013-01-01

    An experiment was conducted comparing multilevel selection in Japanese quail for 43 days weight and survival with birds housed in either kin (K) or random (R) groups. Multilevel selection significantly reduced mortality (6.6% K vs. 8.5% R) and increased weight (1.30 g/MG K vs. 0.13 g/MG R) resulting

  9. Analysis of success and survival in the health industry.

    Science.gov (United States)

    Simonetti, J L; Nykodym, N; Kubiak, S

    Modern management theory accepts that people work for many reasons and to fulfill many goals. People want to survive and succeed and, given the opportunity and the skills, they will. Health professionals seek some of the higher goals. They want to serve their fellow man without being a servant. They want to succeed by providing relief to the suffering; such success must, by necessity, be exceptionally sweet. When human lives are at stake, the word "important" is truly defined. To a health professional, advancement can be an organizational promotion or it can be a professional achievement. In either case, how he/she succeeds will depend on what he/she does. He/she must perform well against a yardstick that grows constantly due to the advances in medical science. He/she must also realize constantly that what he/she performs on is a human being, and must be treated as such. He/she must keep technically able without losing his/her ability to deal in human relations. This study has shown that the health professional accepts the importance of these concepts.

  10. Differential exposure to hazardous air pollution in the United States: a multilevel analysis of urbanization and neighborhood socioeconomic deprivation.

    Science.gov (United States)

    Young, Gary S; Fox, Mary A; Trush, Michael; Kanarek, Norma; Glass, Thomas A; Curriero, Frank C

    2012-06-01

    Population exposure to multiple chemicals in air presents significant challenges for environmental public health. Air quality regulations distinguish criteria air pollutants (CAPs) (e.g., ozone, PM2.5) from hazardous air pollutants (HAPs)-187 chemicals which include carcinogens and others that are associated with respiratory, cardiovascular, neurological and numerous other non-cancer health effects. Evidence of the public's cumulative exposure and the health effects of HAPs are quite limited. A multilevel model is used to assess differential exposure to HAP respiratory, neurological, and cancer hazards (2005) related to the Townsend Index of Socioeconomic Deprivation (TSI), after adjustment for regional population size and economic activity, and local population density. We found significant positive associations between tract TSI and respiratory and cancer HAP exposure hazards, and smaller effects for neurological HAPs. Tracts in the top quintile of TSI have between 38%-60% higher HAP exposure than the bottom quintile; increasing population size from the bottom quintile to the top quintile modifies HAP exposure hazard related to TSI, increasing cancer HAP exposure hazard by 6% to 20% and increasing respiratory HAP exposure hazard by 12% to 27%. This study demonstrates the value of social epidemiological methods for analyzing differential exposure and advancing cumulative risk assessment.

  11. Individual and socioeconomic contextual effects on depressive symptom in Korea: multilevel analysis of cross-sectional nationwide survey.

    Science.gov (United States)

    Lee, Eun-Whan; Park, Jae-Hyun

    2015-02-01

    This study was aimed to examine the relationship between individual, socioeconomic context and depressive symptom among Korean population. Data were the Korean Community Health Survey (KCHS), a nationwide survey collected from 253 local communities including 230,715 adults aged 19 yr or over. To identify depressive symptom, the Center for Epidemiologic Studies Depression scale (CES-D) was used. This study employed multilevel logistic regression to analyze the hierarchical data that included individual and community level variables. The results of this study showed that people in the highest level of community income had a higher risk of depressive symptom compared with people in the lowest (OR, 1.6; 95% CI, 1.4-1.9). In a chi-square test for trend, the prevalence of depressive symptom was significantly increased with increased level of community income among all groups of the family income (P<0.001). Moreover a significant interaction was found between household income and community mean income (OR, 0.98; 95% CI, 0.97-0.99). Among individual level variables, age, sex, education, income, living alone, and the number of illnesses were associated with depressive symptom. This study identified that the level of community income has an inverse association, and its effect is especially stronger among low income individuals.

  12. Associations of Supermarket Characteristics with Weight Status and Body Fat: A Multilevel Analysis of Individuals within Supermarkets (RECORD Study)

    Science.gov (United States)

    Chaix, Basile; Bean, Kathy; Daniel, Mark; Zenk, Shannon N.; Kestens, Yan; Charreire, Hélène; Leal, Cinira; Thomas, Frédérique; Karusisi, Noëlla; Weber, Christiane; Oppert, Jean-Michel; Simon, Chantal; Merlo, Juan; Pannier, Bruno

    2012-01-01

    Purpose Previous research on the influence of the food environment on weight status has often used impersonal measures of the food environment defined for residential neighborhoods, which ignore whether people actually use the food outlets near their residence. To assess whether supermarkets are relevant contexts for interventions, the present study explored between-residential neighborhood and between-supermarket variations in body mass index (BMI) and waist circumference (WC), and investigated associations between brands and characteristics of supermarkets and BMI or WC, after adjustment for individual and residential neighborhood characteristics. Methods Participants in the RECORD Cohort Study (Paris Region, France, 2007–2008) were surveyed on the supermarket (brand and exact location) where they conducted their food shopping. Overall, 7 131 participants shopped in 1 097 different supermarkets. Cross-classified multilevel linear models were estimated for BMI and WC. Results Just 11.4% of participants shopped for food primarily within their residential neighborhood. After accounting for participants' residential neighborhood, people shopping in the same supermarket had a more comparable BMI and WC than participants shopping in different supermarkets. After adjustment for individual and residential neighborhood characteristics, participants shopping in specific supermarket brands, in hard discount supermarkets (especially if they had a low education), and in supermarkets whose catchment area comprised low educated residents had a higher BMI/WC. Conclusion A public health strategy to reduce excess weight may be to intervene on specific supermarkets to change food purchasing behavior, as supermarkets are where dietary preferences are materialized into definite purchased foods. PMID:22496738

  13. Egocentric Network and Condom Use Among Mid-Age Female Sex Workers in China: A Multilevel Modeling Analysis.

    Science.gov (United States)

    Liu, Hongjie

    2016-04-01

    The epidemics of sexually transmitted infections (STIs) have spread among older adults in the world, including China. This study addresses the deficiency of studies about the multiple contextual influences on condom use among mid-age female sex workers (FSWs) over 35 years old. A combination of an egocentric network design and multilevel modeling was used to investigate factors of condom use over mid-age FSWs (egos) particular relationships with sexual partners (alters). Of the 1245 mid-age FSWs interviewed, 73% (907) reported having at least one sexual partner who would provide social support to egos. This generated a total of 1300 ego-alter sex ties in egos' support networks. Condoms were consistently used among one-third of sex ties. At the ego level, condoms were more likely to be used consistently if egos received a middle school education or above, had stronger perceived behavioral control for condom use, or consistently used condoms with other sex clients who were not in their support networks. At the alter level, condoms were not consistently used over spousal ties compared to other ties. Condoms were less likely to be used among alters whom ego trusted and provided emotional support. Cross-level factors (egos' attitudes toward condom use and emotional support from alters) documented a significant positive interaction on consistent condom use. Given the low frequency of condom use, future interventions should focus on mid-age FSWs and their partners within and beyond their support networks.

  14. Biomechanical analysis of multilevel discectomy and excision of posterior longitudinal ligament: An in vitro study in sheep

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    Yilmaz Cem

    2009-01-01

    Full Text Available Aim: This experimental biomechanical study was performed to determine the effects of multilevel anterior cervical discectomy and excision of posterior longitudinal ligament (PLL to stabilize the cervical spine using an in vitro animal model. Materials and Methods: Fifty fresh cadaveric C3-C6 sheep spine specimens were divided into five experimental groups: Group A was the control group; Group B, one-level discectomy; Group C, two- level discectomy, Group D, three-level discectomy, and Group E, three-level discectomy and excision of PLL, respectively. The specimens were subjected to non-destructive loads cycled from zero to five Newton-meter for flexion, extension, right and left lateral bending, and axial rotation on an electrohydraulic test machine. Load displacement curves were obtained via collected data using strain gauges. The values were obtained for all five groups, statistical differences were determined respectively (P < 0.05, ANOVA. Results: One- level discectomy was less stable than the control group, two-level discectomy was less stable than one-level discectomy and three-level discectomy was less stable than two-level discectomy, respectively (P < 0.05. Excision of PLL did not seem to affect stability (P > 0.05. Conclusion: Our data suggested that cervical discectomy decreases stability of sheep spine pieces.

  15. Mindfulness Training Promotes Upward Spirals of Positive Affect and Cognition: Multilevel and Autoregressive Latent Trajectory Modeling Analysis

    Directory of Open Access Journals (Sweden)

    Eric L Garland

    2015-02-01

    Full Text Available Recent theory suggests that positive psychological processes integral to health may be energized through the self-reinforcing dynamics of an upward spiral to counter emotion dysregulation. The present study examined positive emotion-cognition interactions among individuals in partial remission from depression who had been randomly assigned to treatment with mindfulness-based cognitive therapy (MBCT; n = 64 or a wait-list control condition (n = 66. We hypothesized that MBCT stimulates upward spirals by increasing positive affect and positive cognition. Experience sampling assessed changes in affect and cognition during 6 days before and after treatment, which were analyzed with a series of multilevel and autoregressive latent trajectory models. Findings suggest that MBCT was associated with significant increases in trait positive affect and momentary positive cognition, which were preserved through autoregressive and cross-lagged effects driven by global emotional tone. Findings suggest that daily positive affect and cognition are maintained by an upward spiral that might be promoted by mindfulness training.

  16. Linking Health System Responsiveness to Political Rights and Civil Liberties: A Multilevel Analysis Using Data From 44 Countries.

    Science.gov (United States)

    Witvliet, Margot I; Stronks, Karien; Kunst, Anton E; Mahapatra, Tanmay; Arah, Onyebuchi A

    2015-01-01

    Responsiveness is a dimension of health system functioning and might be dependent upon contextual factors related to politics. Given this, we performed cross-national comparisons with the aim of investigating: 1) the associations of political factors with patients' reports of health system responsiveness and 2) the extent to which health input and output might explain these associations. World Health Survey data were analyzed for 44 countries (n = 103 541). Main outcomes included, respectively, 8 and 7 responsiveness domains for inpatient and outpatient care. Linear multilevel regressions were used to assess the associations of politics (namely, civil liberties and political rights), socioeconomic development, health system input, and health system output (measured by maternal mortality) with responsiveness domains, adjusted for demographic factors. Political rights showed positive associations with dignity (regression coefficient = 0.086 [standard error = 0.039]), quality (0.092 [0.049]), and support (0.113 [0.048]) for inpatient care and with dignity (0.075 [0.040]), confidentiality (0.089 [0.043]), and quality (0.124 [0.053]) for outpatient care. Positive associations were observed for civil liberties as well. Health system input and output reduced observed associations. Results tentatively suggest that strengthening political rights and, to a certain extent, civil liberties might improve health system responsiveness, in part through their effect on health system input and output.

  17. The socializing effect of classroom aggression on the development of aggression and social rejection: A two-wave multilevel analysis.

    Science.gov (United States)

    Rohlf, Helena; Krahé, Barbara; Busching, Robert

    2016-10-01

    The current study examined the moderating effect of classroom aggression on the development of individual aggression and on the path from individual aggression to social rejection over time. The study included 1,284 elementary school children and consisted of two data waves 10months apart. At both time points, teachers assessed the children's physical and relational aggression and their social rejection status. Multi-level analyses revealed that the classroom level of relational aggression moderated the link between individual relational aggression at T1 and T2 (b=-0.18, 95% CI [-0.32, -0.05], paggression and T2 social rejection (b=-0.12, 95% CI [-0.23, -0.003], paggression was prevalent increased relational aggression among children with a low level of relational aggression at T1. Furthermore, a high individual level of relational aggression predicted greater social rejection in classrooms with a low level of relational aggression. Children were mainly influenced by their same-gender peers. Boys as a group had a greater influence than girls on their peers of either gender in the domain of relational aggression, whereas girls as a group had a greater influence in the domain of physical aggression. The contributions of analyzing cross-level interaction to understanding the developmental patterns of aggression and social rejection in middle childhood are discussed.

  18. The Pattern of Variation between Diarrhea and Malaria Coexistence with Corresponding Risk Factors in, Chikhwawa, Malawi: A Bivariate Multilevel Analysis.

    Science.gov (United States)

    Masangwi, Salule; Ferguson, Neil; Grimason, Anthony; Morse, Tracy; Kazembe, Lawrence

    2015-07-21

    Developing countries face a huge burden of infectious diseases, a number of which co-exist. This paper estimates the pattern and variation of malaria and diarrhea coexistence in Chikhwawa, a district in Southern Malawi using bivariate multilevel modelling with Bayesian estimation. A probit link was employed to examine hierarchically built data from a survey of individuals (n = 6,727) nested within households (n = 1,380) nested within communities (n = 33). Results show significant malaria [σ²μ₁=0.901 (95% CI:0.746,1.056)] and diarrhea [σ²μ₂=1.009 (95% CI:0.860,1.158)] variations with a strong correlation between them [r(¹,²)μ=0.565] at household level. There are significant malaria [σ²ν₁=0.053 (95% CI: 0.018,0.088)] and diarrhea [σ²ν₂=0.099(95% CI : 0.030,0.168) ] variations at community level but with a small correlation [r(¹,²) ν=0.124] between them. There is also significant correlation between malaria and diarrhea at individual level [ r(¹,²) e=0.241]. These results suggest a close association between reported malaria-like illness and diarrheal illness especially at household and individual levels in Southern Malawi.

  19. Variables that predict academic achievement in the Spanish compulsory secondary educational system: a longitudinal, multi-level analysis.

    Science.gov (United States)

    Martín, Elena; Martínez-Arias, Rosario; Marchesi, Alvaro; Pérez, Eva M

    2008-11-01

    This article presents a study whose objective was to identify certain personal and institutional variables that are associated with academic achievement among Spanish, secondary school students, and to analyze their influence on the progress of those students over the course of that stage of their education. In order to do this, a longitudinal, multi-level study was conducted in which a total of 965 students and 27 different schools were evaluated in Language, Math and Social Science at three different times (beginning, middle and end of the period). The results show progress in all the schools and in all areas. As for the personal, student variables, the longitudinal, HLM analyses confirmed the importance of sex and sociocultural background and, distinguishing it from other studies, also the predictive capacity of meta-cognitive abilities and learning strategies on success in school. On the institutional level, the school climate and teachers' expectations of their students were the most relevant of the variables studied. The size of the school, the percentage of students who repeat grades, and the leadership of the administration also explained a portion of the variance in some areas.

  20. Does school social capital modify socioeconomic inequality in mental health? A multi-level analysis in Danish schools.

    Science.gov (United States)

    Nielsen, Line; Koushede, Vibeke; Vinther-Larsen, Mathilde; Bendtsen, Pernille; Ersbøll, Annette Kjær; Due, Pernille; Holstein, Bjørn E

    2015-09-01

    It seems that social capital in the neighbourhood has the potential to reduce socioeconomic differences in mental health among adolescents. Whether school social capital is a buffer in the association between socioeconomic position and mental health among adolescents remains uncertain. The aim of this study is therefore to examine if the association between socioeconomic position and emotional symptoms among adolescents is modified by school social capital. The Health Behaviour in School-aged Children Methodology Development Study 2012 provided data on 3549 adolescents aged 11-15 in two municipalities in Denmark. Trust in the school class was used as an indicator of school social capital. Prevalence of daily emotional symptoms in each socioeconomic group measured by parents' occupational class was calculated for each of the three categories of school classes: school classes with high trust, moderate trust and low trust. Multilevel logistic regression analyses with parents' occupational class as the independent variable and daily emotional symptoms as the dependent variable were conducted stratified by level of trust in the school class. The prevalence of emotional symptoms was higher among students in school classes with low trust (12.9%) compared to school classes with high trust (7.2%) (p social capital may reduce mental health problems and diminish socioeconomic inequality in mental health among adolescents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Inequalities in mortality by socioeconomic factors and Roma ethnicity in the two biggest cities in Slovakia: a multilevel analysis.

    Science.gov (United States)

    Rosicova, Katarina; Reijneveld, Sijmen A; Madarasova Geckova, Andrea; Stewart, Roy E; Rosic, Martin; Groothoff, Johan W; van Dijk, Jitse P

    2015-11-05

    The socioeconomic and ethnic composition of urban neighbourhoods may affect mortality, but evidence on Central European cities is lacking. The aim of this study was to assess the associations between socioeconomic and ethnic neighbourhood indicators and the mortality of individuals aged 20-64 years old in the two biggest cities of the Slovak Republic. We obtained data on the characteristics of neighbourhoods and districts (educational level, unemployment, income and share of Roma) and on individual mortality of residents aged 20-64 years old, for the two largest cities in the Slovak Republic (Bratislava and Kosice) in the period 2003-2005. We performed multilevel Poisson regression analyses adjusted for age and gender on the individual (mortality), neighbourhood (education level and share of Roma in population) and district levels (unemployment and income). The proportions of Roma and of low-educated residents were associated with mortality at the neighbourhood level in both cities. Mutually adjusted, only the association with the proportion of Roma remained in the model (risk ratio 1.02; 95 % confidence interval 1.01-1.04). The area indicators - high education, income and unemployment - were not associated with mortality. The proportion of Roma is associated with early mortality in the two biggest cities in the Slovak Republic.

  2. A multilevel analysis on the relationship between neighbourhood poverty and public hospital utilization: is the high Indigenous morbidity avoidable?

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    Guthridge Steven L

    2011-09-01

    Full Text Available Abstract Background The estimated life expectancy at birth for Indigenous Australians is 10-11 years less than the general Australian population. The mean family income for Indigenous people is also significantly lower than for non-Indigenous people. In this paper we examine poverty or socioeconomic disadvantage as an explanation for the Indigenous health gap in hospital morbidity in Australia. Methods We utilised a cross-sectional and ecological design using the Northern Territory public hospitalisation data from 1 July 2004 to 30 June 2008 and socio-economic indexes for areas (SEIFA from the 2006 census. Multilevel logistic regression models were used to estimate odds ratios and confidence intervals. Both total and potentially avoidable hospitalisations were investigated. Results This study indicated that lifting SEIFA scores for family income and education/occupation by two quintile categories for low socio-economic Indigenous groups was sufficient to overcome the excess hospital utilisation among the Indigenous population compared with the non-Indigenous population. The results support a reframing of the Indigenous health gap as being a consequence of poverty and not simplistically of ethnicity. Conclusions Socio-economic disadvantage is a likely explanation for a substantial proportion of the hospital morbidity gap between Indigenous and non-Indigenous populations. Efforts to improve Indigenous health outcomes should recognise poverty as an underlying determinant of the health gap.

  3. Multilevel Bloom Filters for P2P Flows Identification Based on Cluster Analysis in Wireless Mesh Network

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    Xia-an Bi

    2015-01-01

    Full Text Available With the development of wireless mesh networks and distributed computing, lots of new P2P services have been deployed and enrich the Internet contents and applications. The rapid growth of P2P flows brings great pressure to the regular network operation. So the effective flow identification and management of P2P applications become increasingly urgent. In this paper, we build a multilevel bloom filters data structure to identify the P2P flows through researches on the locality characteristics of P2P flows. Different level structure stores different numbers of P2P flow rules. According to the characteristics values of the P2P flows, we adjust the parameters of the data structure of bloom filters. The searching steps of the scheme traverse from the first level to the last level. Compared with the traditional algorithms, our method solves the drawbacks of previous schemes. The simulation results demonstrate that our algorithm effectively enhances the performance of P2P flows identification. Then we deploy our flow identification algorithm in the traffic monitoring sensors which belong to the network traffic monitoring system at the export link in the campus network. In the real environment, the experiment results demonstrate that our algorithm has a fast speed and high accuracy to identify the P2P flows; therefore, it is suitable for actual deployment.

  4. The Downside of Marketization: A Multilevel Analysis of Housing Tenure and Types in Reform-era Urban China

    Science.gov (United States)

    Fu, Qiang; Zhu, Yushu; Ren, Qiang

    2015-01-01

    Based on data from the 2005 National Population Sample Survey and compiled covariates of 205 prefectures, this research adopted principal-component and multilevel-logistic analyses to study homeownership in urban China. Although the housing reform has severed the link between work units and residence, working in state sectors (government, state-owned enterprises and collective firms) remained significant in determining a household’s entitlement to reform-era housing with heavy subsidies or better qualities. While the prefecture-level index of marketization reduced local homeownership of self-built housing, affordable housing and privatized housing, its effect is moderated by cross-level interactions with income, education and working in state sectors across different types of housing. Meanwhile, the index of political and market connections promoted all types of homeownership except for self-built housing. By situating the downside of marketization within a context of urban transformation, this research not only challenges the teleological premise of the neoliberal market transition theory but calls for research on institutional dynamics and social consequences of urban transformation in China. PMID:25432608

  5. Multilevel modelling and public health policy

    NARCIS (Netherlands)

    Leyland, Alastair H.; Groenewegen, Peter P.

    2003-01-01

    Background: Multilevel modelling is a statistical technique that extends ordinary regression analysis to the situation where the data are hierarchical. Such data form an increasingly common evidence base for public health policy, and as such it is important that policy makers should be aware of this

  6. Multilevel modelling and public health policy.

    NARCIS (Netherlands)

    Leyland, A.H.; Groenewegen, P.P.

    2003-01-01

    BACKGROUND: Multilevel modelling is a statistical technique that extends ordinary regression analysis to the situation where the data are hierarchical. Such data form an increasingly common evidence base for public health policy, and as such it is important that policy makers should be aware of this

  7. Multilevel Group Analysis on Bayesian in fMRI Time Series%Bayesian方法对fMRI数据的多层群组分析

    Institute of Scientific and Technical Information of China (English)

    周广田; 杨丰; 田晓英

    2016-01-01

    This paper suggests a method to process fMRI time series based on Bayesian inference for group analysis. The method uses multilevel divided by voxel, subject and group as pair comparison to reinforce posterior probability in group analysis from single subjects as priors. And also it combines classical statistics, i.e., t-test to obtain voxel activation at subject level as prior for Bayesian inference at group level. It effectively solves computation expensive and complexity. And it shows robust on Bayesian inference for group analysis.%本文采用Bayesian方法对fMRI时间序列数据对群组进行分析,群组按照体素、脑体、个体分为多层,比较个体的特征选取作为先验加强群组的后验计算,对个体的参数估计结合经典统计方法获得体素的激活区域作为群组Bayesian推理的先验,可以有效解决计算复杂性和计算成本,有效应用在群组分析中。

  8. The influence of the macro-environment on physical activity: a multilevel analysis of 38 countries worldwide

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    Bosdriesz Jizzo R

    2012-09-01

    Full Text Available Abstract Background As indicated by the ANGELO framework and similar models, various environmental factors influence population levels of physical activity (PA. To date attention has focused on the micro-level environment, while evidence on the macro-level environment remains scarce and mostly limited to high-income countries. This study aims to investigate whether environmental factors at macro-level are associated with PA among a broader range of countries. Methods Data from the World Health Survey (WHS was used to analyze 177,035 adults from 38 (mostly low and middle income countries. The International Physical Activity Questionnaire-Short Form (IPAQ-S was used to measure PA. Respondents were classified as active or inactive for vigorous PA, moderate PA and walking. Multilevel logistic regression was performed to assess associations between macro-level environmental factors and the prevalence of PA, with control for individual-level socioeconomic factors. Results The prevalence of PA varied widely between countries and types of PA (5.0%-93.8%. A negative association was found between gross domestic product and PA, odds ratios for men were 0.76 (95% CI: 0.65-0.89 for moderate PA and 0.79 (95% CI: 0.63-0.98 for walking. A higher temperature was associated with less PA (all types and higher urbanization was associated with less vigorous and moderate PA. More gender equality was also associated with more walking for women. Governmental functioning and literacy rate were not found to be associated with any type of PA. Conclusions This exploratory study indicates that factors such as climate, economic development and cultural factors are determinants of the level of overall PA at national levels. This underlines the suggestion that the macro-environment should be regarded as an important influence on PA.

  9. The influence of the macro-environment on physical activity: a multilevel analysis of 38 countries worldwide.

    Science.gov (United States)

    Bosdriesz, Jizzo R; Witvliet, Margot I; Visscher, Tommy L S; Kunst, Anton E

    2012-09-11

    As indicated by the ANGELO framework and similar models, various environmental factors influence population levels of physical activity (PA). To date attention has focused on the micro-level environment, while evidence on the macro-level environment remains scarce and mostly limited to high-income countries. This study aims to investigate whether environmental factors at macro-level are associated with PA among a broader range of countries. Data from the World Health Survey (WHS) was used to analyze 177,035 adults from 38 (mostly low and middle income) countries. The International Physical Activity Questionnaire-Short Form (IPAQ-S) was used to measure PA. Respondents were classified as active or inactive for vigorous PA, moderate PA and walking. Multilevel logistic regression was performed to assess associations between macro-level environmental factors and the prevalence of PA, with control for individual-level socioeconomic factors. The prevalence of PA varied widely between countries and types of PA (5.0%-93.8%). A negative association was found between gross domestic product and PA, odds ratios for men were 0.76 (95% CI: 0.65-0.89) for moderate PA and 0.79 (95% CI: 0.63-0.98) for walking. A higher temperature was associated with less PA (all types) and higher urbanization was associated with less vigorous and moderate PA. More gender equality was also associated with more walking for women. Governmental functioning and literacy rate were not found to be associated with any type of PA. This exploratory study indicates that factors such as climate, economic development and cultural factors are determinants of the level of overall PA at national levels. This underlines the suggestion that the macro-environment should be regarded as an important influence on PA.

  10. Racial/ethnic variation in breastfeeding across the US: a multilevel analysis from the National Survey of Children's Health, 2007.

    Science.gov (United States)

    Belanoff, Candice M; McManus, Beth M; Carle, Adam C; McCormick, Marie C; Subramanian, S V

    2012-04-01

    We examined whether differences across states in race/ethnicity-specific breastfeeding rates are due solely to state differences in individual factors associated with breastfeeding or additionally, certain state "contextual" factors. Using data from the 2007 National Survey of Children's Health, multilevel models examined whether state variability in race/ethnicity specific breastfeeding initiation and duration to 6 months were explained by (1) individual sociodemographic characteristics of women in states, and (2) an aggregate state measure of the availability of evidence-based maternity care services related to breastfeeding. Observed variability of race/ethnicity-specific breastfeeding rates was only minimally reduced after adjusting for sociodemographic characteristics (Median Odds Ratios (MOR), breastfeeding initiation: non-Hispanic White = 1.46, non-Hispanic Black = 2.26; Hispanic = 1.89. MOR, breastfeeding for 6 months: non-Hispanic White = 1.36, non-Hispanic Black = 1.84; Hispanic = 1.56). Overall variability in the degree of state gaps changed little in adjusted models (breastfeeding initiation: non-Hispanic Black σ(2) = 0.74, se 0.28, Hispanic σ(2) = 0.45, se 0.11; breastfeeding to 6-months: non-Hispanic Black σ(2) = 0.41, se 0.10, Hispanic σ(2) = 0.22, se 0.05). The measure of maternity care services was positively associated with breastfeeding overall but generally did not explain a substantial portion of between-state variability nor the overall variability in racial/ethnic gaps. Contextual sources of variation in state breastfeeding practices and disparities remain poorly understood. Differences in the socioeconomic makeup of states do not fully explain variability. The association of state breastfeeding rates and disparities with relevant policy and practice factors should be further investigated.

  11. Community-level influences on women's experience of intimate partner violence and terminated pregnancy in Nigeria: a multilevel analysis.

    Science.gov (United States)

    Antai, Diddy; Adaji, Sunday

    2012-11-14

    Intimate partner violence (IPV) is a major public health problem with serious consequences for women's physical, mental, sexual and reproductive health. Reproductive health outcomes such as unwanted and terminated pregnancies, fetal loss or child loss during infancy, non-use of family planning methods, and high fertility are increasingly recognized. However, little is known about the role of community influences on women's experience of IPV and its effect on terminated pregnancy, given the increased awareness of IPV being a product of social context. This study sought to examine the role of community-level norms and characteristics in the association between IPV and terminated pregnancy in Nigeria. Multilevel logistic regression analyses were performed on nationally-representative cross-sectional data including 19,226 women aged 15-49 years in Nigeria. Data were collected by a stratified two-stage sampling technique, with 888 primary sampling units (PSUs) selected in the first sampling stage, and 7,864 households selected through probability sampling in the second sampling stage. Women who had experienced physical IPV, sexual IPV, and any IPV were more likely to have terminated a pregnancy compared to women who had not experienced these IPV types.IPV types were significantly associated with factors reflecting relationship control, relationship inequalities, and socio-demographic characteristics. Characteristics of the women aggregated at the community level (mean education, justifying wife beating, mean age at first marriage, and contraceptive use) were significantly associated with IPV types and terminated pregnancy. Findings indicate the role of community influence in the association between IPV-exposure and terminated pregnancy, and stress the need for screening women seeking abortions for a history of abuse.

  12. Associations of supermarket characteristics with weight status and body fat: a multilevel analysis of individuals within supermarkets (RECORD study.

    Directory of Open Access Journals (Sweden)

    Basile Chaix

    Full Text Available PURPOSE: Previous research on the influence of the food environment on weight status has often used impersonal measures of the food environment defined for residential neighborhoods, which ignore whether people actually use the food outlets near their residence. To assess whether supermarkets are relevant contexts for interventions, the present study explored between-residential neighborhood and between-supermarket variations in body mass index (BMI and waist circumference (WC, and investigated associations between brands and characteristics of supermarkets and BMI or WC, after adjustment for individual and residential neighborhood characteristics. METHODS: Participants in the RECORD Cohort Study (Paris Region, France, 2007-2008 were surveyed on the supermarket (brand and exact location where they conducted their food shopping. Overall, 7 131 participants shopped in 1 097 different supermarkets. Cross-classified multilevel linear models were estimated for BMI and WC. RESULTS: Just 11.4% of participants shopped for food primarily within their residential neighborhood. After accounting for participants' residential neighborhood, people shopping in the same supermarket had a more comparable BMI and WC than participants shopping in different supermarkets. After adjustment for individual and residential neighborhood characteristics, participants shopping in specific supermarket brands, in hard discount supermarkets (especially if they had a low education, and in supermarkets whose catchment area comprised low educated residents had a higher BMI/WC. CONCLUSION: A public health strategy to reduce excess weight may be to intervene on specific supermarkets to change food purchasing behavior, as supermarkets are where dietary preferences are materialized into definite purchased foods.

  13. Determinants of the use of health care services: multilevel analysis in the Metropolitan Region of Sao Paulo

    Science.gov (United States)

    Chiavegatto, Alexandre Dias Porto; Wang, Yuan-Pang; Malik, Ana Maria; Takaoka, Julia; Viana, Maria Carmen; Andrade, Laura Helena

    2015-01-01

    OBJECTIVE To evaluate the individual and contextual determinants of the use of health care services in the metropolitan region of Sao Paulo. METHODS Data from the Sao Paulo Megacity study – the Brazilian version of the World Mental Health Survey multicenter study – were used. A total of 3,588 adults living in 69 neighborhoods in the metropolitan region of Sao Paulo, SP, Southeastern Brazil, including 38 municipalities and 31 neighboring districts, were selected using multistratified sampling of the non-institutionalized population. Multilevel Bayesian logistic models were adjusted to identify the individual and contextual determinants of the use of health care services in the past 12 months and presence of a regular physician for routine care. RESULTS The contextual characteristics of the place of residence (income inequality, violence, and median income) showed no significant correlation (p > 0.05) with the use of health care services or with the presence of a regular physician for routine care. The only exception was the negative correlation between living in areas with high income inequality and presence of a regular physician (OR: 0.77; 95%CI 0.60;0.99) after controlling for individual characteristics. The study revealed a strong and consistent correlation between individual characteristics (mainly education and possession of health insurance), use of health care services, and presence of a regular physician. Presence of chronic and mental illnesses was strongly correlated with the use of health care services in the past year (regardless of the individual characteristics) but not with the presence of a regular physician. CONCLUSIONS Individual characteristics including higher education and possession of health insurance were important determinants of the use of health care services in the metropolitan area of Sao Paulo. A better understanding of these determinants is essential for the development of public policies that promote equitable use of health care

  14. Macro-level gender equality and alcohol consumption: a multi-level analysis across U.S. States.

    Science.gov (United States)

    Roberts, Sarah C M

    2012-07-01

    Higher levels of women's alcohol consumption have long been attributed to increases in gender equality. However, only limited research examines the relationship between gender equality and alcohol consumption. This study examined associations between five measures of state-level gender equality and five alcohol consumption measures in the United States. Survey data regarding men's and women's alcohol consumption from the 2005 Behavioral Risk Factor Surveillance System were linked to state-level indicators of gender equality. Gender equality indicators included state-level women's socioeconomic status, gender equality in socioeconomic status, reproductive rights, policies relating to violence against women, and women's political participation. Alcohol consumption measures included past 30-day drinker status, drinking frequency, binge drinking, volume, and risky drinking. Other than drinker status, consumption is measured for drinkers only. Multi-level linear and logistic regression models adjusted for individual demographics as well as state-level income inequality, median income, and % Evangelical Protestant/Mormon. All gender equality indicators were positively associated with both women's and men's drinker status in models adjusting only for individual-level covariates; associations were not significant in models adjusting for other state-level characteristics. All other associations between gender equality and alcohol consumption were either negative or non-significant for both women and men in models adjusting for other state-level factors. Findings do not support the hypothesis that higher levels of gender equality are associated with higher levels of alcohol consumption by women or by men. In fact, most significant findings suggest that higher levels of equality are associated with less alcohol consumption overall.

  15. Community-level influences on women's experience of intimate partner violence and terminated pregnancy in Nigeria: a multilevel analysis

    Directory of Open Access Journals (Sweden)

    Antai Diddy

    2012-11-01

    Full Text Available Abstract Background Intimate partner violence (IPV is a major public health problem with serious consequences for women’s physical, mental, sexual and reproductive health. Reproductive health outcomes such as unwanted and terminated pregnancies, fetal loss or child loss during infancy, non-use of family planning methods, and high fertility are increasingly recognized. However, little is known about the role of community influences on women's experience of IPV and its effect on terminated pregnancy, given the increased awareness of IPV being a product of social context. This study sought to examine the role of community-level norms and characteristics in the association between IPV and terminated pregnancy in Nigeria. Methods Multilevel logistic regression analyses were performed on nationally-representative cross-sectional data including 19,226 women aged 15–49 years in Nigeria. Data were collected by a stratified two-stage sampling technique, with 888 primary sampling units (PSUs selected in the first sampling stage, and 7,864 households selected through probability sampling in the second sampling stage. Results Women who had experienced physical IPV, sexual IPV, and any IPV were more likely to have terminated a pregnancy compared to women who had not experienced these IPV types. IPV types were significantly associated with factors reflecting relationship control, relationship inequalities, and socio-demographic characteristics. Characteristics of the women aggregated at the community level (mean education, justifying wife beating, mean age at first marriage, and contraceptive use were significantly associated with IPV types and terminated pregnancy. Conclusion Findings indicate the role of community influence in the association between IPV-exposure and terminated pregnancy, and stress the need for screening women seeking abortions for a history of abuse.

  16. Socio-economic, socio-political and socio-emotional variables explaining school bullying: a country-wide multilevel analysis.

    Science.gov (United States)

    Chaux, Enrique; Molano, Andrés; Podlesky, Paola

    2009-01-01

    Why do some countries, regions and schools have more bullying than others? What socio-economic, socio-political and other larger contextual factors predict school bullying? These open questions inspired this study with 53.316 5th- and 9th-grade students (5% of the national student population in these grades), from 1,000 schools in Colombia. Students completed a national test of citizenship competencies, which included questions about bullying and about families, neighborhoods and their own socio-emotional competencies. We combined these data with community violence and socio-economic conditions of all Colombian municipalities, which allowed us to conduct multilevel analyses to identify municipality- and school-level variables predicting school bullying. Most variance was found at the school level. Higher levels of school bullying were related to more males in the schools, lower levels of empathy, more authoritarian and violent families, higher levels of community violence, better socio-economic conditions, hostile attributional biases and more beliefs supporting aggression. These results might reflect student, classroom and school contributions because student-level variables were aggregated at the school level. Although in small portions, violence from the decades-old-armed conflict among guerrillas, paramilitaries and governmental forces predicted school bullying at the municipal level for 5th graders. For 9th graders, inequality in land ownership predicted school bullying. Neither poverty, nor population density or homicide rates contributed to explaining bullying. These results may help us advance toward understanding how the larger context relates to school bullying, and what socio-emotional competencies may help us prevent the negative effects of a violent and unequal environment.

  17. Polysubstance use and misuse or abuse of prescription opioid analgesics: a multi-level analysis of international data.

    Science.gov (United States)

    Morley, Katherine I; Ferris, Jason A; Winstock, Adam R; Lynskey, Michael T

    2017-06-01

    Increasing mortality and morbidity associated with opioid analgesics has led to concerns about their misuse and abuse, even when obtained through a prescription. These concerns have been most pronounced in the United States, but limited data make it difficult to determine whether it is a problem in other countries. We investigated opioid analgesic misuse and abuse in participants from the Global Drug Survey 2015 resident in the United States (N = 1334), United Kingdom (N = 1199), France (N = 1258), Germany (N = 866), and Australia (N = 1013) who had used at least 1 prescription opioid analgesic medication in the past year. We also investigated the relationship with polysubstance use, one of the most consistent predictors of problematic opioid analgesic use. Data included misuse and abuse of codeine, hydrocodone, oxycodone, and tramadol; ability to obtain a prescription; different sources for obtaining drugs; and past-year use of benzodiazepines and illicit drugs. In multilevel models, country of residence accounted for less than 3% of the variance in opioid analgesic misuse or abuse. Adjusting for country of residence and sociodemographic factors, use of illicit drugs and benzodiazepines was associated with 4-fold greater odds of misuse (odds ratio 4.36, 95% confidence interval 3.29-5.93) and 6-fold greater odds of abuse compared with not using either drug (odds ratio 6.49, 95% confidence interval 4.0-10.48), although the strength of the association with abuse varied by country. Misuse and abuse by those prescribed opioid analgesics seem to be a problem that is not limited to the United States and warrant attention on an international scale.

  18. Socioeconomic inequalities in adolescent smoking across 35 countries: a multilevel analysis of the role of family, school and peers.

    Science.gov (United States)

    Moor, Irene; Rathmann, Katharina; Lenzi, Michela; Pförtner, Timo-Kolja; Nagelhout, Gera E; de Looze, Margreet; Bendtsen, Pernille; Willemsen, Marc; Kannas, Lasse; Kunst, Anton E; Richter, Matthias

    2015-06-01

    Tobacco-related heath inequalities are a major public health concern, with smoking being more prevalent among lower socioeconomic groups. The aim of this study is to investigate the mechanisms leading to socioeconomic inequalities in smoking among 15-year-old adolescents by examining the mediating role of psychosocial factors in the peer group, family and school environment. Data were derived from the international WHO-collaborative 'Health Behaviour in School-aged Children (HBSC)' study 2005/2006, including 52 907 15-year-old students from 35 European and North American countries. Socioeconomic position was measured by the Family Affluence Scale. Multilevel logistic regression models were conducted to examine the contribution of family, school and peer factors in explaining the association between family affluence and weekly smoking. Across countries, adolescents from low affluent families had an increased risk of weekly smoking (OR(boys) 1.14, confidence interval (CI) 1.05-1.23; OR(girls) 1.36, CI 1.26-1.46) compared with adolescents from high affluent families. Family and school factors mediated the association between family affluence and smoking to a high extent up to 100% (boys) and 81% (girls) in joint analyses. The most important single factors were family structure, relationships with parents, academic achievement and school satisfaction. Peer factors did not mediate the association between family affluence and adolescent smoking. The association between socioeconomic status and adolescent weekly smoking can largely be explained by an unequal distribution of family- and school-related factors. Focusing on the parent-adolescent relationship and adolescent school achievement can help to better understand inequalities in adolescent smoking behaviour. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  19. AIDS knowledge and sexual activity among Flemish secondary school students: a multilevel analysis of the effects of type of education

    Science.gov (United States)

    2010-01-01

    Background The behavior of adolescents puts them at an increased risk for HIV and other STIs, and their knowledge about HIV/AIDS is often inadequate. An understanding of how AIDS knowledge and sexual activity co-vary among Flemish secondary school students and of how education type, specifically, affects these students is limited. This study addresses the question of whether the effects of education type on HIV/AIDS knowledge and sexual activity are independent of the socio-demographic characteristics of the students. Methods Data from the Flemish Educational Assessment survey, which collected data from a large representative sample of third- and fifth-grade high school students (N = 11,872), were used. Data were analyzed using multilevel logistic and Poisson regression techniques. Results There is an indication that type of education affects both an adolescent's sexual activity and his/her AIDS knowledge; these effects prove robust for differences in socio-economic backgrounds. Students in lower status education types are more likely to be sexually active and to have poorer AIDS knowledge. The relationship between AIDS knowledge and sexual activity is, however, more complex. Although students in education types with poorer AIDS knowledge are more sexually active, within each of these groups the sexually active have better AIDS knowledge than the non-sexually active. There is also evidence of active information seeking by sexually active students, which leads to improved AIDS knowledge. Conclusion These findings are consistent with the literature on the role of the educational system in the reproduction of social inequalities. Students from lower status education types are at increased sexual risk compared to those from higher status types. There is also evidence of active information seeking by sexually active students, which leads to improved AIDS knowledge. PMID:20092623

  20. AIDS knowledge and sexual activity among Flemish secondary school students: a multilevel analysis of the effects of type of education

    Directory of Open Access Journals (Sweden)

    Berten Hans

    2010-01-01

    Full Text Available Abstract Background The behavior of adolescents puts them at an increased risk for HIV and other STIs, and their knowledge about HIV/AIDS is often inadequate. An understanding of how AIDS knowledge and sexual activity co-vary among Flemish secondary school students and of how education type, specifically, affects these students is limited. This study addresses the question of whether the effects of education type on HIV/AIDS knowledge and sexual activity are independent of the socio-demographic characteristics of the students. Methods Data from the Flemish Educational Assessment survey, which collected data from a large representative sample of third- and fifth-grade high school students (N = 11,872, were used. Data were analyzed using multilevel logistic and Poisson regression techniques. Results There is an indication that type of education affects both an adolescent's sexual activity and his/her AIDS knowledge; these effects prove robust for differences in socio-economic backgrounds. Students in lower status education types are more likely to be sexually active and to have poorer AIDS knowledge. The relationship between AIDS knowledge and sexual activity is, however, more complex. Although students in education types with poorer AIDS knowledge are more sexually active, within each of these groups the sexually active have better AIDS knowledge than the non-sexually active. There is also evidence of active information seeking by sexually active students, which leads to improved AIDS knowledge. Conclusion These findings are consistent with the literature on the role of the educational system in the reproduction of social inequalities. Students from lower status education types are at increased sexual risk compared to those from higher status types. There is also evidence of active information seeking by sexually active students, which leads to improved AIDS knowledge.

  1. Do welfare regimes influence the association between disability and self-perceived health? A multilevel analysis of 57 countries.

    Science.gov (United States)

    Foubert, Josephine; Levecque, Katia; Van Rossem, Ronan; Romagnoli, Alessia

    2014-09-01

    Disability is usually associated with poorer self-rated health. However, as many people with disabilities do not consider themselves unhealthy, the association may not be as straightforward as it appears. This study examines whether the relationship between disability and self-rated health is dependent on a country's welfare regime. Welfare regimes can play a significant role in securing the needs of disabled people and lessening their social exclusion. However, welfare regimes also label disabled people accordingly, before they become entitled to specific provisions and services. Being given a low status label and being dependent on welfare provisions might trigger a negative self-evaluation of health. Using data from 57 countries of the World Health Survey of 2002-2004, the multilevel regression analyses show that people with a disability tend to rate their health worse than people without any disability. Moreover, the strength of this negative association varies significantly across countries and is affected by a country's welfare regime. The association is the strongest in the various Welfare State regimes (mostly European countries) and the weakest in Informal-Security regimes (Latin-American and Asian countries) and in Insecurity regimes (African countries). Disabled people living in Welfare States regimes tend to rate their health worse than people in other regimes. These findings confirm that welfare regimes play a role in shaping the health perception of disabled people and that processes of labeling may result in unintended and negative consequences of welfare programs. Research on the nexus between disability and self-rated health that neglects this macro-social context of welfare regimes may lead to undifferentiated and even incorrect conclusions.

  2. Multilevel analysis of the association between posterior restorations and gingival health in young adults: a population-based birth cohort.

    Science.gov (United States)

    Demarco, Flávio Fernando; Correa, Marcos Britto; Horta, Bernardo; Barros, Aluísio J; Peres, Karen Glazer; Peres, Marco Aurélio

    2013-12-01

    To investigate the association of direct posterior restorations with gingival bleeding and dental calculus in young adults from a birth cohort. A representative sample (n = 720) of 5914 infants born live in Pelotas, Brazil, in 1982, were prospectively investigated, and posterior restorations and periodontal health outcomes assessed when they were 24 years of age. Tooth-level exploratory variables included the presence and number of restoration's surfaces. Demographic and socio-economic characteristics, oral health instructions, dental floss usage, dental caries presence and smoking were also considered whilst gingival bleeding and dental calculus were the outcomes. Multilevel logistic regression was carried out. Class I cavities were found in 15.2% (95% CI 14.5-15.9) of the teeth and class II in 3.6% (3.3-4.0). Percentage of teeth with gingival bleeding was 6.1% (5.6-6.6) and that with dental calculus 22% (21.2-22.8). Even after all the individual variables were controlled for, the presence of a class I [OR1.51 (1.14-2.00)] and class II [OR 1.76 (1.04-2.97)] cavities was positively associated with gingival bleeding. Class I [OR1.36 (1.13-1.65)] and Class II [OR1.80 (1.28-2.53)] cavities were associated with dental calculus also. Posterior restoration and higher number of restored surfaces was associated with a higher prevalence of gingival bleeding and dental calculus around the restoration. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Determinants of the use of health care services: multilevel analysis in the Metropolitan Region of Sao Paulo.

    Science.gov (United States)

    Chiavegatto Filho, Alexandre Dias Porto; Wang, Yuan-Pang; Malik, Ana Maria; Takaoka, Julia; Viana, Maria Carmen; Andrade, Laura Helena

    2015-01-01

    OBJECTIVE To evaluate the individual and contextual determinants of the use of health care services in the metropolitan region of Sao Paulo. METHODS Data from the Sao Paulo Megacity study - the Brazilian version of the World Mental Health Survey multicenter study - were used. A total of 3,588 adults living in 69 neighborhoods in the metropolitan region of Sao Paulo, SP, Southeastern Brazil, including 38 municipalities and 31 neighboring districts, were selected using multistratified sampling of the non-institutionalized population. Multilevel Bayesian logistic models were adjusted to identify the individual and contextual determinants of the use of health care services in the past 12 months and presence of a regular physician for routine care. RESULTS The contextual characteristics of the place of residence (income inequality, violence, and median income) showed no significant correlation (p > 0.05) with the use of health care services or with the presence of a regular physician for routine care. The only exception was the negative correlation between living in areas with high income inequality and presence of a regular physician (OR: 0.77; 95%CI 0.60;0.99) after controlling for individual characteristics. The study revealed a strong and consistent correlation between individual characteristics (mainly education and possession of health insurance), use of health care services, and presence of a regular physician. Presence of chronic and mental illnesses was strongly correlated with the use of health care services in the past year (regardless of the individual characteristics) but not with the presence of a regular physician. CONCLUSIONS Individual characteristics including higher education and possession of health insurance were important determinants of the use of health care services in the metropolitan area of Sao Paulo. A better understanding of these determinants is essential for the development of public policies that promote equitable use of health care

  4. What factors explain the number of physical therapy treatment sessions in patients referred with low back pain; a multilevel analysis

    Directory of Open Access Journals (Sweden)

    Dekker Joost

    2005-11-01

    Full Text Available Abstract Background It is well-known that the number of physical therapy treatment sessions varies over treatment episodes. Information is lacking, however, on the source and explanation of the variation. The purposes of the current study are: 1 to determine how the variance in the number of physical therapy treatment sessions in patients with non-specific low back pain (LBP in the Netherlands is distributed over patient level, therapist level and practice level; and 2 to determine the factors that explain the variance. Methods Data were used from a national registration network on physical therapy. Our database contained information on 1,733 patients referred with LBP, treated by 97 therapists working in 41 practices. The variation in the number of treatment sessions was investigated by means of multilevel regression analyses. Results Eighty-eight per cent of the variation in the number of treatment sessions for patients with LBP is located at patient level and seven per cent is located at practice level. It was possible to explain thirteen per cent of all variance. The duration of the complaint, prior therapy, and the patients' age and gender in particular are related to the number of physical therapy treatment sessions. Conclusion Our results suggest that the number of physical therapy treatment sessions in patients with LBP mainly depends on patient characteristics. More variation needs to be explained, however, to improve the transparency of care. Future research should examine the contribution of psychosocial factors, baseline disability, and the ability to learn motor behavior as possible factors in the variation in treatment sessions.

  5. Survivability analysis of wireless Ad hoc network using stochastic reward nets

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jing; CUI Gang; LIU Hong-wei; WANG Hui-qiang

    2008-01-01

    To provide services in presence of failures or attacks in a timely manner, the network survivability was analyzed. Based on stochastic Petri nets, we put forward an effective model for ad hec network and adopt a two-phase approach consisting of the steady-state availability analysis and the system transient performance anal-ysis, then provide a quantitative approach for analysis of the network survivability. The results show that the proposed model is useful for the design and evaluation of the wireless ad hoc network.

  6. Handling incomplete smoking history data in survival analysis.

    Science.gov (United States)

    Furukawa, Kyoji; Preston, Dale L; Misumi, Munechika; Cullings, Harry M

    2014-10-26

    While data are unavoidably missing or incomplete in most observational studies, consequences of mishandling such incompleteness in analysis are often overlooked. When time-varying information is collected irregularly and infrequently over a long period, even precisely obtained data may implicitly involve substantial incompleteness. Motivated by an analysis to quantitatively evaluate the effects of smoking and radiation on lung cancer risks among Japanese atomic-bomb survivors, we provide a unique application of multiple imputation to incompletely observed smoking histories under the assumption of missing at random. Predicting missing values for the age of smoking initiation and, given initiation, smoking intensity and cessation age, analyses can be based on complete, though partially imputed, smoking histories. A simulation study shows that multiple imputation appropriately conditioned on the outcome and other relevant variables can produce consistent estimates when data are missing at random. Our approach is particularly appealing in large cohort studies where a considerable amount of time-varying information is incomplete under a mechanism depending in a complex manner on other variables. In application to the motivating example, this approach is expected to reduce estimation bias that might be unavoidable in naive analyses, while keeping efficiency by retaining known information.

  7. 30-Day Survival Probabilities as a Quality Indicator for Norwegian Hospitals: Data Management and Analysis.

    Directory of Open Access Journals (Sweden)

    Sahar Hassani

    Full Text Available The Norwegian Knowledge Centre for the Health Services (NOKC reports 30-day survival as a quality indicator for Norwegian hospitals. The indicators have been published annually since 2011 on the website of the Norwegian Directorate of Health (www.helsenorge.no, as part of the Norwegian Quality Indicator System authorized by the Ministry of Health. Openness regarding calculation of quality indicators is important, as it provides the opportunity to critically review and discuss the method. The purpose of this article is to describe the data collection, data pre-processing, and data analyses, as carried out by NOKC, for the calculation of 30-day risk-adjusted survival probability as a quality indicator.Three diagnosis-specific 30-day survival indicators (first time acute myocardial infarction (AMI, stroke and hip fracture are estimated based on all-cause deaths, occurring in-hospital or out-of-hospital, within 30 days counting from the first day of hospitalization. Furthermore, a hospital-wide (i.e. overall 30-day survival indicator is calculated. Patient administrative data from all Norwegian hospitals and information from the Norwegian Population Register are retrieved annually, and linked to datasets for previous years. The outcome (alive/death within 30 days is attributed to every hospital by the fraction of time spent in each hospital. A logistic regression followed by a hierarchical Bayesian analysis is used for the estimation of risk-adjusted survival probabilities. A multiple testing procedure with a false discovery rate of 5% is used to identify hospitals, hospital trusts and regional health authorities with significantly higher/lower survival than the reference. In addition, estimated risk-adjusted survival probabilities are published per hospital, hospital trust and regional health authority. The variation in risk-adjusted survival probabilities across hospitals for AMI shows a decreasing trend over time: estimated survival probabilities

  8. 30-Day Survival Probabilities as a Quality Indicator for Norwegian Hospitals: Data Management and Analysis.

    Science.gov (United States)

    Hassani, Sahar; Lindman, Anja Schou; Kristoffersen, Doris Tove; Tomic, Oliver; Helgeland, Jon

    2015-01-01

    The Norwegian Knowledge Centre for the Health Services (NOKC) reports 30-day survival as a quality indicator for Norwegian hospitals. The indicators have been published annually since 2011 on the website of the Norwegian Directorate of Health (www.helsenorge.no), as part of the Norwegian Quality Indicator System authorized by the Ministry of Health. Openness regarding calculation of quality indicators is important, as it provides the opportunity to critically review and discuss the method. The purpose of this article is to describe the data collection, data pre-processing, and data analyses, as carried out by NOKC, for the calculation of 30-day risk-adjusted survival probability as a quality indicator. Three diagnosis-specific 30-day survival indicators (first time acute myocardial infarction (AMI), stroke and hip fracture) are estimated based on all-cause deaths, occurring in-hospital or out-of-hospital, within 30 days counting from the first day of hospitalization. Furthermore, a hospital-wide (i.e. overall) 30-day survival indicator is calculated. Patient administrative data from all Norwegian hospitals and information from the Norwegian Population Register are retrieved annually, and linked to datasets for previous years. The outcome (alive/death within 30 days) is attributed to every hospital by the fraction of time spent in each hospital. A logistic regression followed by a hierarchical Bayesian analysis is used for the estimation of risk-adjusted survival probabilities. A multiple testing procedure with a false discovery rate of 5% is used to identify hospitals, hospital trusts and regional health authorities with significantly higher/lower survival than the reference. In addition, estimated risk-adjusted survival probabilities are published per hospital, hospital trust and regional health authority. The variation in risk-adjusted survival probabilities across hospitals for AMI shows a decreasing trend over time: estimated survival probabilities for AMI in

  9. Perceived and Objective Measures of Neighborhood Walkability and Physical Activity among Adults in Japan: A Multilevel Analysis of a Nationally Representative Sample.

    Science.gov (United States)

    Hanibuchi, Tomoya; Nakaya, Tomoki; Yonejima, Mayuko; Honjo, Kaori

    2015-10-23

    Although associations between a person's neighborhood and their health have been studied internationally, most studies have been limited to a few cities or towns. Therefore, we used a nationally representative sample to explore whether perceived and objective neighborhood walkability was associated with the physical activity of residents. Data were analyzed from the Japanese General Social Surveys of 2010 (n = 2395; 1114 men and 1281 women). Perceived walkability was scored using factor analysis for the respondents' perceptions of neighborhood conditions, while objective walkability was measured using the geographic information system approach. Finally, multilevel logistic regression analysis was performed to examine whether neighborhood walkability was associated with the frequency of leisure-time physical activity (LTPA) among respondents. We found that perceived walkability was positively associated with the frequency of LTPA (odds ratio of the highest quartile was 1.53 (1.14-2.05) compared with the lowest quartile); however, objective walkability showed no association. When stratified by gender, an association between perceived walkability and LTPA was observed among women, but only a marginally significant association was present between objective walkability and LTPA among men. We conclude that the association between neighborhood walkability and LTPA can be partially generalized across Japan.

  10. Multilevel particle filter

    KAUST Repository

    Law, Kody

    2016-01-06

    This talk will pertain to the filtering of partially observed diffusions, with discrete-time observations. It is assumed that only biased approximations of the diffusion can be obtained, for choice of an accuracy parameter indexed by l. A multilevel estimator is proposed, consisting of a telescopic sum of increment estimators associated to the successive levels. The work associated to O( 2) mean-square error between the multilevel estimator and average with respect to the filtering distribution is shown to scale optimally, for example as O( 2) for optimal rates of convergence of the underlying diffusion approximation. The method is illustrated on some toy examples as well as estimation of interest rate based on real S&P 500 stock price data.

  11. MULTILEVEL ITERATION METHODS FOR SOLVING LINEAR ILL-POSED PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In this paper we develop multilevel iteration methods for solving linear systems resulting from the Galerkin method and Tikhonov regularization for ill-posed problems. The algorithm and its convergence analysis are presented in an abstract framework.

  12. Predicting survival of Salmonella in low-water activity foods: an analysis of literature data.

    Science.gov (United States)

    Santillana Farakos, Sofia M; Schaffner, Donald W; Frank, Joseph F

    2014-09-01

    Factors such as temperature, water activity (aw), substrate, culture media, serotype, and strain influence the survival of Salmonella in low-aw foods. Predictive models for Salmonella survival in low-aw foods at temperatures ranging from 21 to 80(u) C and water activities below 0.6 were previously developed. Literature data on survival of Salmonella in low-aw foods were analyzed in the present study to validate these predictive models and to determine global influencing factors. The results showed the Weibull model provided suitable fits to the data in 75% of the curves as compared with the log-linear model. The secondary models predicting the time required for log-decimal reduction (log δ) and shape factor (log β) values were useful in predicting the survival of Salmonella in low-aw foods. Statistical analysis indicated overall fail-safe secondary models, with 88% of the residuals in the acceptable and safe zones (foods and its influencing factors.

  13. The role of gender and friends' gender on peer socialization of adolescent drinking: a prospective multilevel social network analysis.

    Science.gov (United States)

    Deutsch, Arielle R; Steinley, Douglas; Slutske, Wendy S

    2014-09-01

    Although socializing effects of friends' drinking on adolescent drinking behavior have been firmly established in previous literature, study results on the importance of gender, as well as the specific role that gender may play in peer socialization, are very mixed. Given the increasing importance of gender in friendships (particularly opposite-sex friendships) during adolescence, it is necessary to better understand the nuanced roles that gender can play in peer socialization effects on alcohol use. In addition, previous studies focusing on the interplay between individual gender and friends' gender have been largely dyadic; less is known about potential gendered effects of broader social networks. The current study sought to further investigate potential effects of gender on friends' influence on adolescent drinking behavior with particular emphasis on the number of same-sex and opposite-sex friends within one's friendship network, as well as closeness to these friends. Using Waves I and II of the saturated sample of the National Longitudinal Study of Adolescent Health (Add Health), adolescent friendship networks were used to calculate the mean drinking behaviors of adolescent friends. Multi-level models estimated the effects of individual drinking behaviors, friend drinking behaviors, and school-level drinking behaviors on adolescent drinking 1 year later, as well as moderating effects of gender composition of friendship groups and male and female friend closeness on the relationship between friends' drinking behaviors and adolescent drinking behavior. Results documented that gender composition of friendship groups did not influence the effect of friends' drinking on individual drinking 1 year later. However, closeness to friends did influence this relationship. As closeness to male friends decreased, the influence of their drinking behavior increased, for both boys and girls. A similar effect was found for female friends, but only for boys. Female friend

  14. Determinants and causes of neonatal mortality in Jimma Zone, Southwest Ethiopia: a multilevel analysis of prospective follow up study.

    Directory of Open Access Journals (Sweden)

    Gurmesa Tura Debelew

    Full Text Available BACKGROUND: Ethiopia is among the countries with the highest neonatal mortality with the rate of 37 deaths per 1000 live births. In spite of many efforts by the government and other partners, non-significant decline has been achieved in the last 15 years. Thus, identifying the determinants and causes are very crucial for policy and program improvement. However, studies are scarce in the country in general and in Jimma zone in particular. OBJECTIVE: To identify the determinants and causes of neonatal mortality in Jimma Zone, Southwest Ethiopia. METHODS: A prospective follow-up study was conducted among 3463 neonates from September 2012 to December 2013. The data were collected by interviewer-administered structured questionnaire and analyzed by SPSS V.20.0 and STATA 13. Verbal autopsies were conducted to identify causes of neonatal death. Mixed-effects multilevel logistic regression model was used to identify determinants of neonatal mortality. RESULTS: The status of neonatal mortality rate was 35.5 (95%CI: 28.3, 42.6 per 1000 live births. Though significant variation existed between clusters in relation to neonatal mortality, cluster-level variables were found to have non-significant effect on neonatal mortality. Individual-level variables such as birth order, frequency of antenatal care use, delivery place, gestation age at birth, premature rupture of membrane, complication during labor, twin births, size of neonate at birth and neonatal care practice were identified as determinants of neonatal mortality. Birth asphyxia (47.5%, neonatal infections (34.3% and prematurity (11.1% were the three leading causes of neonatal mortality accounting for 93%. CONCLUSIONS: This study revealed high status of neonatal mortality in the study area. Higher-level variables had less importance in determining neonatal mortality. Individual level variables related to care during pregnancy, intra-partum complications and care, neonatal conditions and the immediate

  15. An Asian population-based survival analysis of patients with distal esophageal and gastric cardia adenocarcinomas

    Institute of Scientific and Technical Information of China (English)

    ZHENG Bin; ZHENG Wei; ZHU Yong,; WU Wei-dong; CHEN Chun

    2012-01-01

    Background Gastroesophageal junction adenocarcinomas include adenocarcinomas of the distal esophagus(DE)and gastric cardia(GC).It is controversial whether these tumors are the same entity and whether they have the same survival rates.Patients with DE and GC adenocarcinomas have a similar survival rate in the US;however,data are lacking in Asian countries.Therefore,we conducted a retrospective study to understand the implications of the tumor location in the survival of Asian patients.Methods A total of 209 patients with pathologically confirmed DE and GC adenocarcinomas,from 2005 to 2007,were included in the study.We identified patients with adenocarcinomas of the DE(DE group,n=91)and GC(GC group)(n=118).We performed an unadjusted survival analysis using the Kaplan-Meier method,and used a Cox proportional hazards regression model to adjust for potential confounding covariates.Results We found no significant difference between the overall survival of the DE and GC groups.The 3-year survival rates were 44.8% and 53.0%,respectively,and the 5-year survival rates were 27.9% and 30.2%,respectively(P=0.162).We found no significant difference in early staging,advanced staging,different T staging,and different N staging,between the groups.Both advanced post-operative N staging and advanced AJCC staging had a significant adverse effect on survival.Conclusions Patients with DE and GC adenocarcinomas have similar survival rates in the Asian population.Both post-operative N staging and AJCC staging are prognostic factors.

  16. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon

    2016-01-08

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  17. Survival Analysis and its Associated Factors of Beta Thalassemia Major in Hamadan Province

    Directory of Open Access Journals (Sweden)

    Reza Zamani

    2015-05-01

    Full Text Available Background: There currently is a lack of knowledge about the long-term survival of patients with beta thalassemia (BT, particularly in regions with low incidence of the disease. The aim of the present study was to determine the survival rate of the patients with BT major and the factors associated with the survival time. Methods: This retrospective cohort study was performed in Hamadan province, located in the west of Iran. The study included patients that referred to the provincial hospitals during 16 year period from 1997 to 2013. The follow up of each subject was calculated from the date of birth to the date of death. Demographic and clinical data were extracted from patients’ medical records using a checklist. Statistical analysis included the Kaplan-Meier method to analyze survivals, log-rank to compare curves between groups, and Cox regression for multivariate prognostic analysis. Results: A total of 133 patients with BT major were enrolled, 54.9% of whom were male and 66.2% were urban. The 10-, 20- and 30-year survival rate for all patients were 98.3%, 88.4% and 80.5%, respectively. Based on hazard ratio (HR, we found that accompanied diseases (P=0.01, blood type (P=0.03 and residency status (P=0.01 were significant predictors for the survival time of patients. Conclusion: The survival rate of BT patients has improved. Future researches such as prospective designs are required for the estimation of survival rate and to find other prognostic factors, which have reliable sources of data.

  18. Importance of rare gene copy number alterations for personalized tumor characterization and survival analysis.

    Science.gov (United States)

    Seifert, Michael; Friedrich, Betty; Beyer, Andreas

    2016-10-03

    It has proven exceedingly difficult to ascertain rare copy number alterations (CNAs) that may have strong effects in individual tumors. We show that a regulatory network inferred from gene expression and gene copy number data of 768 human cancer cell lines can be used to quantify the impact of patient-specific CNAs on survival signature genes. A focused analysis of tumors from six tissues reveals that rare patient-specific gene CNAs often have stronger effects on signature genes than frequent gene CNAs. Further comparison to a related network-based approach shows that the integration of indirectly acting gene CNAs significantly improves the survival analysis.

  19. The influence of compositional and contextual factors on non-receipt of basic vaccines among children of 12-23-month old in India: a multilevel analysis.

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    Daouda Sissoko

    Full Text Available BACKGROUND: Children unreached by vaccination are at higher risk of poor health outcomes and India accounts for nearly a quarter of unvaccinated children worldwide. The objective of this study was to investigate compositional and contextual determinants of non-receipt of childhood vaccines in India using multilevel modelling. METHODS AND FINDINGS: We studied characteristics of unvaccinated children using the District Level Health and Facility Survey 3, a nationally representative probability sample containing 65 617 children aged 12-23 months from 34 Indian states and territories. We developed four-level Bayesian binomial regression models to examine the determinants of non-vaccination. The analysis considered two outcomes: completely unvaccinated (CUV children who had not received any of the eight vaccine doses recommended by India's Universal Immunization Programme, and children who had not received any dose from routine immunisation services (no RI. The no RI category includes CUV children and those who received only polio doses administered via mass campaigns. Overall, 4.83% (95% CI: 4.62-5.06 of children were CUV while 12.01% (11.68-12.35 had received no RI. Individual compositional factors strongly associated with CUV were: non-receipt of tetanus immunisation for mothers during pregnancy (OR = 3.65 [95% CrI: 3.30-4.02], poorest household wealth index (OR = 2.44 [1.81-3.22] no maternal schooling (OR = 2.43 [1.41-4.05] and no paternal schooling (OR = 1.83 [1.30-2.48]. In rural settings, the influence of maternal illiteracy disappeared whereas the role of household wealth index was reinforced. Factors associated with no RI were similar to those for CUV, but effect sizes for individual compositional factors were generally larger. Low maternal education was the strongest risk factor associated with no RI in all models. All multilevel models found significant variability at community, district, and state levels net of

  20. "Does anger regulation mediate the discrimination-mental health link among Mexican-origin adolescents? A longitudinal mediation analysis using multilevel modeling": Correction to Park et al. (2016).

    Science.gov (United States)

    2017-02-01

    Reports an error in "Does Anger Regulation Mediate the Discrimination-Mental Health Link Among Mexican-Origin Adolescents? A Longitudinal Mediation Analysis Using Multilevel Modeling" by Irene J. K. Park, Lijuan Wang, David R. Williams and Margarita Alegría (Developmental Psychology, Advanced Online Publication, Nov 28, 2016, np). In the article, there were several typographical errors in the Recruitment and Procedures section. The percentage of mothers who responded to survey items should have been 99.3%. Additionally, the youths surveyed at T2 and T3 should have been n=246 . Accordingly, the percentage of youths surveyed in T2 and T3 should have been 91.4% and the percentage of mothers surveyed at T2 and T3 should have been 90.7%. Finally, the youths missing at T2 should have been n= 23, and therefore the attrition rate for youth participants should have been 8.6. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2016-57671-001.) Although prior research has consistently documented the association between racial/ethnic discrimination and poor mental health outcomes, the mechanisms that underlie this link are still unclear. The present 3-wave longitudinal study tested the mediating role of anger regulation in the discrimination-mental health link among 269 Mexican-origin adolescents (Mage = 14.1 years, SD = 1.6; 57% girls), 12 to 17 years old. Three competing anger regulation variables were tested as potential mediators: outward anger expression, anger suppression, and anger control. Longitudinal mediation analyses were conducted using multilevel modeling that disaggregated within-person effects from between-person effects. Results indicated that outward anger expression was a significant mediator; anger suppression and anger control were not significant mediators. Within a given individual, greater racial/ethnic discrimination was associated with more frequent outward anger expression. In turn

  1. Risk factors and survival analysis of the esophageal cancer in the population of Jammu, India.

    Science.gov (United States)

    Sehgal, S; Kaul, S; Gupta, B B; Dhar, M K

    2012-01-01

    To identify the risk factors of esophageal cancer and study their effect on the survival rates patients of Jammu region, India. Detailed information was collected on socio-demographic, dietary and clinico-pathological parameters for 200 case control pairs. Discrete (categorical) data of 2 independent groups (control and cases) were summarized in frequency (%) and compared by using Chi-square (χ2 ) test. The mean age of two independent groups was compared by independent Student's t-test. To find out potential risk factor (s), the variable (s) found significant in univariate analysis were further subjected to multivariate logistic regression analysis. The association of potential risk factors with patients survival (3-year overall survival) was done by Kaplan-Meier survival curve analysis using Log-rank test. A 2-tailed (a = 2) P food (OR = 1.77, 95% CI = 1.10-2.85) and red chilly (OR = 1.76, 95% CI = 1.07-2.89). Probability of survival lowered significantly (P factor of esophageal cancer in Jammu region, followed by the salt tea, smoking and the sundried food.

  2. Survival after liver resection in metastatic colorectal cancer: review and meta-analysis of prognostic factors

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    Kanas GP

    2012-11-01

    Full Text Available Gena P Kanas,1 Aliki Taylor,2 John N Primrose,3 Wendy J Langeberg,4 Michael A Kelsh,4 Fionna S Mowat,1 Dominik D Alexander,5 Michael A Choti,6 Graeme Poston71Health Sciences, Exponent, Menlo Park, CA, USA; 2Centre for Observational Research, Amgen, Uxbridge, UK; 3Department of Surgery, Southampton General Hospital, Southampton, UK; 4Center for Observational Research, Amgen, Thousand Oaks, CA, USA; 5Health Sciences, Exponent, Chicago, IL, USA; 6Johns Hopkins Hospital, Baltimore, MD, USA; 7Department of Surgery, Aintree University Hospitals NHS, Liverpool, UKBackground: Hepatic metastases develop in approximately 50% of colorectal cancer (CRC cases. We performed a review and meta-analysis to evaluate survival after resection of CRC liver metastases (CLMs and estimated the summary effect for seven prognostic factors.Methods: Studies published between 1999 and 2010, indexed on Medline, that reported survival after resection of CLMs, were reviewed. Meta-relative risks for survival by prognostic factor were calculated, stratified by study size and annual clinic volume. Cumulative meta-analysis results by annual clinic volume were plotted.Results: Five- and 10-year survival ranged from 16% to 74% (median 38% and 9% to 69% (median 26%, respectively, based on 60 studies. The overall summary median survival time was 3.6 (range: 1.7–7.3 years. Meta-relative risks (95% confidence intervals by prognostic factor were: node positive primary, 1.6 (1.5–1.7; carcinoembryonic antigen level, 1.9 (1.1–3.2; extrahepatic disease, 1.9 (1.5–2.4; poor tumor grade, 1.9 (1.3–2.7; positive margin, 2.0 (1.7–2.5; >1 liver metastases, 1.6 (1.4–1.8; and >3 cm tumor diameter, 1.5 (1.3–1.8. Cumulative meta-analyses by annual clinic volume suggested improved survival with increasing volume.Conclusion: The overall median survival following CLM liver resection was 3.6 years. All seven investigated prognostic factors showed a modest but significant predictive

  3. Chinese insurance agents in "bad barrels": a multilevel analysis of the relationship between ethical leadership, ethical climate and business ethical sensitivity.

    Science.gov (United States)

    Zhang, Na; Zhang, Jian

    2016-01-01

    The moral hazards and poor public image of the insurance industry, arising from insurance agents' unethical behavior, affect both the normal operation of an insurance company and decrease applicants' confidence in the company. Contrarily, these scandals may demonstrate that the organizations were "bad barrels" in which insurance agents' unethical decisions were supported or encouraged by the organization's leadership or climate. The present study brings two organization-level factors (ethical leadership and ethical climate) together and explores the role of ethical climate on the relationship between the ethical leadership and business ethical sensitivity of Chinese insurance agents. Through the multilevel analysis of 502 insurance agents from 56 organizations, it is found that organizational ethical leadership is positively related to the organizational ethical climate; organizational ethical climate is positively related to business ethical sensitivity, and organizational ethical climate fully mediates the relationship between organizational ethical leadership and business ethical sensitivity. Organizational ethical climate plays a completely mediating role in the relationship between organizational ethical leadership and business ethical sensitivity. The integrated model of ethical leadership, ethical climate and business ethical sensitivity makes several contributions to ethics theory, research and management.

  4. Individual and community-level socioeconomic position and its association with adolescents experience of childhood sexual abuse: a multilevel analysis of six countries in Sub-Saharan Africa

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    Ismail Yahaya

    2014-01-01

    Full Text Available Abstract: Background: Childhood sexual abuse (CSA is a substantial global health and human rights problem and consequently a growing concern in sub-Saharan Africa. We examined the association between individual and community-level socioeconomic status (SES and the likelihood of reporting CSA. Methods: We applied multiple multilevel logistic regression analysis on Demographic and Health Survey data for 6,351female adolescents between the ages of 15 and 18 years from six countries in sub-Saharan Africa, between 2006 and 2008. Results: About 70% of the reported cases of CSA were between 14 and 17 years. Zambia had the highest proportion of reported cases of CSA (5.8%. At the individual and community level, we found that there was no association between CSA and socioeconomic position. This study provides evidence that the likelihood of reporting CSA cut across all individual SES as well as all community socioeconomic strata. Conclusions: We found no evidence of socioeconomic differentials in adolescents’ experience of CSA, suggesting that adolescents from the six countries studied experienced CSA regardless of their individual- and community-level socioeconomic position. However, we found some evidence of geographical clustering, adolescents in the same community are subject to common contextual influences. Further studies are needed to explore possible effects of countries’ political, social, economic, legal, and cultural impact on childhood sexual abuse.

  5. Associations between state minimum wage policy and health care access: a multi-level analysis of the 2004 Behavioral Risk Factor survey.

    Science.gov (United States)

    McCarrier, Kelly P; Martin, Diane P; Ralston, James D; Zimmerman, Frederick J

    2010-05-01

    Minimum wage policies have been advanced as mechanisms to improve the economic conditions of the working poor. Both positive and negative effects of such policies on health care access have been hypothesized, but associations have yet to be thoroughly tested. To examine whether the presence of minimum wage policies in excess of the federal standard of $5.15 per hour was associated with health care access indicators among low-skilled adults of working age, a cross-sectional analysis of 2004 Behavioral Risk Factor Surveillance System data was conducted. Self-reported health insurance status and experience with cost-related barriers to needed medical care were adjusted in multi-level logistic regression models to control for potential confounding at the state, county, and individual levels. State-level wage policy was not found to be associated with insurance status or unmet medical need in the models, providing early evidence that increased minimum wage rates may neither strengthen nor weaken access to care as previously predicted.

  6. Relationships between Religion and Two Forms of Homonegativity in Europe—A Multilevel Analysis of Effects of Believing, Belonging and Religious Practice

    Science.gov (United States)

    Doebler, Stefanie

    2015-01-01

    This paper examines relationships between religion and two forms of homonegativity across 43 European countries using a bivariate response binary logistic multilevel model. The model analyzes effects of religious believing, belonging and practice on two response variables: a) a moral rejection of homosexuality as a practice and b) intolerance toward homosexuals as a group. The findings indicate that both forms of homonegativity are prevalent in Europe. Traditional doctrinal religious believing (belief in a personal God) is positively related to a moral rejection of homosexuality but to a much lesser extent associated with intolerance toward homosexuals as a group. Members of religious denominations are more likely than non-members to reject homosexuality as morally wrong and to reject homosexuals as neighbors. The analysis found significant differences between denominations that are likely context-dependent. Attendance at religious services is positively related to homonegativity in a majority of countries. The findings vary considerably across countries: Religion is more strongly related to homonegativity in Western than in Eastern Europe. In the post-soviet countries homonegativity appears to be largely a secular phenomenon. National contexts of high religiosity, high perceived government corruption, high income inequality and shortcomings in the implementation of gay rights in the countries’ legislations are statistically related to higher levels of both moralistic homonegativity and intolerance toward homosexuals as a group. PMID:26247352

  7. Relationships between Religion and Two Forms of Homonegativity in Europe--A Multilevel Analysis of Effects of Believing, Belonging and Religious Practice.

    Science.gov (United States)

    Doebler, Stefanie

    2015-01-01

    This paper examines relationships between religion and two forms of homonegativity across 43 European countries using a bivariate response binary logistic multilevel model. The model analyzes effects of religious believing, belonging and practice on two response variables: a) a moral rejection of homosexuality as a practice and b) intolerance toward homosexuals as a group. The findings indicate that both forms of homonegativity are prevalent in Europe. Traditional doctrinal religious believing (belief in a personal God) is positively related to a moral rejection of homosexuality but to a much lesser extent associated with intolerance toward homosexuals as a group. Members of religious denominations are more likely than non-members to reject homosexuality as morally wrong and to reject homosexuals as neighbors. The analysis found significant differences between denominations that are likely context-dependent. Attendance at religious services is positively related to homonegativity in a majority of countries. The findings vary considerably across countries: Religion is more strongly related to homonegativity in Western than in Eastern Europe. In the post-soviet countries homonegativity appears to be largely a secular phenomenon. National contexts of high religiosity, high perceived government corruption, high income inequality and shortcomings in the implementation of gay rights in the countries' legislations are statistically related to higher levels of both moralistic homonegativity and intolerance toward homosexuals as a group.

  8. The Triple P-Positive Parenting Program: a systematic review and meta-analysis of a multi-level system of parenting support.

    Science.gov (United States)

    Sanders, Matthew R; Kirby, James N; Tellegen, Cassandra L; Day, Jamin J

    2014-06-01

    This systematic review and meta-analysis examined the effects of the multilevel Triple P-Positive Parenting Program system on a broad range of child, parent and family outcomes. Multiple search strategies identified 116 eligible studies conducted over a 33-year period, with 101 studies comprising 16,099 families analyzed quantitatively. Moderator analyses were conducted using structural equation modeling. Risk of bias within and across studies was assessed. Significant short-term effects were found for: children's social, emotional and behavioral outcomes (d=0.473); parenting practices (d=0.578); parenting satisfaction and efficacy (d=0.519); parental adjustment (d=0.340); parental relationship (d=0.225) and child observational data (d=0.501). Significant effects were found for all outcomes at long-term including parent observational data (d=0.249). Moderator analyses found that study approach, study power, Triple P level, and severity of initial child problems produced significant effects in multiple moderator models when controlling for other significant moderators. Several putative moderators did not have significant effects after controlling for other significant moderators. The positive results for each level of the Triple P system provide empirical support for a blending of universal and targeted parenting interventions to promote child, parent and family wellbeing.

  9. Relationships between Religion and Two Forms of Homonegativity in Europe--A Multilevel Analysis of Effects of Believing, Belonging and Religious Practice.

    Directory of Open Access Journals (Sweden)

    Stefanie Doebler

    Full Text Available This paper examines relationships between religion and two forms of homonegativity across 43 European countries using a bivariate response binary logistic multilevel model. The model analyzes effects of religious believing, belonging and practice on two response variables: a a moral rejection of homosexuality as a practice and b intolerance toward homosexuals as a group. The findings indicate that both forms of homonegativity are prevalent in Europe. Traditional doctrinal religious believing (belief in a personal God is positively related to a moral rejection of homosexuality but to a much lesser extent associated with intolerance toward homosexuals as a group. Members of religious denominations are more likely than non-members to reject homosexuality as morally wrong and to reject homosexuals as neighbors. The analysis found significant differences between denominations that are likely context-dependent. Attendance at religious services is positively related to homonegativity in a majority of countries. The findings vary considerably across countries: Religion is more strongly related to homonegativity in Western than in Eastern Europe. In the post-soviet countries homonegativity appears to be largely a secular phenomenon. National contexts of high religiosity, high perceived government corruption, high income inequality and shortcomings in the implementation of gay rights in the countries' legislations are statistically related to higher levels of both moralistic homonegativity and intolerance toward homosexuals as a group.

  10. Modeling contextual effects using individual-level data and without aggregation: an illustration of multilevel factor analysis (MLFA) with collective efficacy.

    Science.gov (United States)

    Dunn, Erin C; Masyn, Katherine E; Johnston, William R; Subramanian, S V

    2015-01-01

    Population health scientists increasingly study how contextual-level attributes affect individual health. A major challenge in this domain relates to measurement, i.e., how best to measure and create variables that capture characteristics of individuals and their embedded contexts. This paper presents an illustration of multilevel factor analysis (MLFA), an analytic method that enables researchers to model contextual effects using individual-level data without using derived variables. MLFA uses the shared variance in sets of observed items among individuals within the same context to estimate a measurement model for latent constructs; it does this by decomposing the total sample variance-covariance matrix into within-group (e.g., individual-level) and between-group (e.g., contextual-level) matrices and simultaneously modeling distinct latent factor structures at each level. We illustrate the MLFA method using items capturing collective efficacy, which were self-reported by 2,599 adults in 65 census tracts from the Los Angeles Family and Neighborhood Survey (LAFANS). MLFA identified two latent factors at the individual level and one factor at the neighborhood level. Indicators of collective efficacy performed differently at each level. The ability of MLFA to identify different latent factor structures at each level underscores the utility of this analytic tool to model and identify attributes of contexts relevant to health.

  11. Multilevel analysis of the impact of environmental factors and agricultural practices on the concentration in hay of microorganisms responsible for farmer's lung disease.

    Science.gov (United States)

    Gbaguidi-Haore, Houssein; Roussel, Sandrine; Reboux, Gabriel; Dalphin, Jean-Charles; Piarroux, Renaud

    2009-01-01

    Farmer's lung disease (FLD) is common in eastern France. It is the main form of occupational hypersensitivity pneumonitis, caused by chronic inhalation of microorganisms (antigens) from mouldy hay, straw, or grain. The purpose of this study was to assess, with a panel of data collected between 1997-2003, environmental factors and agricultural practices that independently modify concentrations in hay of microorganisms potentially responsible for FLD. A total of 629 hay samples from 86 farms were included in statistical analyses using linear multilevel regression models allowing to consider the nested structure of the data: individual-level (batch of hay) and group-level (farm). The outcome variable of these models was the concentration in hay (logarithmic value of concentration+1) of microorganisms incriminated in FLD (Absidia corymbifera, Eurotium spp., thermophilic actinomycetes). The simultaneous analysis of batch of hay- and farm-level factors showed that bad climatic conditions of harvest, high-density hay-packing modes, (especially round bales) and altitude (2nd plateau, ]700-900] m) were the main factors associated with high concentrations of these microorganisms in hay. This study allowed clarification of the factors that influence the microbial concentration of hay with etiological agents of FLD.

  12. Survival Analysis and Actuarial Parameters of Sternechus subsignatus (Coleoptera: Curculionidae) Adults.

    Science.gov (United States)

    Guillermina Socías, María; Van Nieuwenhove, Guido; Murúa, María Gabriela; Willink, Eduardo; Liljesthröm, Gerardo Gustavo

    2016-04-01

    The soybean stalk weevil, Sternechus subsignatus Boheman 1836 (Coleoptera: Curculionidae), is a very serious soybean pest in the Neotropical region. Both adults and larvae feed on soybean, causing significant yield losses. Adult survival was evaluated during three soybean growing seasons under controlled environmental conditions. A survival analysis was performed using a parametric survival fit approach in order to generate survival curves and obtain information that could help optimize integrated management strategies for this weevil pest. Sex of the weevils, crop season, fortnight in which weevils emerged, and their interaction were studied regarding their effect on adult survival. The results showed that females lived longer than males, but both genders were actually long-lived, reaching 224 and 176 d, respectively. Mean lifetime (l50) was 121.88±4.56 d for females and 89.58±2.72 d for males. Although variations were observed in adult longevities among emergence fortnights and soybean seasons, only in December and January fortnights of the 2007–2008 season and December fortnights of 2009–2010 did the statistically longest and shortest longevities occur, respectively. Survivorship data (lx) of adult females and males were fitted to the Weibull frequency distribution model. The survival curve was type I for both sexes, which indicated that mortality corresponded mostly to old individuals.

  13. Percutaneous Irreversible Electroporation: Long-term survival analysis of 71 patients with inoperable malignant hepatic tumors

    Science.gov (United States)

    Niessen, C.; Thumann, S.; Beyer, L.; Pregler, B.; Kramer, J.; Lang, S.; Teufel, A.; Jung, E. M.; Stroszczynski, C.; Wiggermann, P.

    2017-01-01

    Aim of this retrospective analysis was to evaluate the survival times after percutaneous irreversible electroporation (IRE) in inoperable liver tumors not amenable to thermal ablation. 71 patients (14 females, 57 males, median age 63.5 ± 10.8 years) with 103 liver tumors were treated in 83 interventions using IRE (NanoKnife® system). The median tumor short-axis diameter was 1.9 cm (minimum 0.4 cm, maximum 4.5 cm). 35 patients had primary liver tumors and 36 patients had liver metastases. The Kaplan-Meier method was employed to calculate the survival rates, and the different groups were compared using multivariate log-rank and Wilcoxon tests. The overall median survival time was 26.3 months; the median survival of patients with primary land secondary liver cancer did not significantly differ (26.8 vs. 19.9 months; p = 0.41). Patients with a tumor diameter >3 cm (p Child-Pugh class B or C cirrhosis died significantly earlier than patients with Child-Pugh class A (p < 0.05). Patients with very early stage HCC survived significantly longer than patients with early stage HCC with a median survival of 22.3 vs. 13.7 months (p < 0.05). PMID:28266600

  14. SURVIVAL ANALYSIS AND GROWTH OF Cordia trichotoma, BORAGINACEAE, LAMIALES, IN MATO GROSSO DO SUL STATE, BRAZIL

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    Sergio Luiz Salvadori

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812357The evaluation of a plant survival percentage and growth may reflect its competitive ability in plantcommunity. Cordia trichotoma is a common native tree in Mato Grosso do Sul State and one of the mostpromising for planting. This study monitored the survival percentage and growth of Cordia trichotomaunder different conditions such as weeding and receiving or not fertilization. The experiment started inSeptember 2008 and it was concluded in March 2010. The seeds collection and sowing were held in urbanarea of Mundo Novo Municipality and the area for permanent planting to measure seedlings survival andgrowth was set at Japorã Municipality, Fazenda Santa Clara. Seedlings were planted in two categories: theuse or not of fertilizer and crowing resulting in four distinct groups: block fertilizer bare earth (ATN, bareland block without fertilizer (BTN, fertilizer and crown block (AC and without fertilizer and crownedblock (BC. The results indicated high survival of Cordia trichotoma in the seedling transplant system from bed to bags. The BC block showed the highest percentage of survival, but the smaller increments in height.The AC, ATN and BTN blocks presented the same survival pattern and similar average growth. However,there may be differences in nutritional and chemical composition of the soil suggesting sector analysis forfuture studies.

  15. A Multilevel Analysis of Patient Engagement and Patient-Reported Outcomes in Primary Care Practices of Accountable Care Organizations.

    Science.gov (United States)

    Shortell, Stephen M; Poon, Bing Ying; Ramsay, Patricia P; Rodriguez, Hector P; Ivey, Susan L; Huber, Thomas; Rich, Jeremy; Summerfelt, Tom

    2017-06-01

    The growing movement toward more accountable care delivery and the increasing number of people with chronic illnesses underscores the need for primary care practices to engage patients in their own care. For adult primary care practices seeing patients with diabetes and/or cardiovascular disease, we examined the relationship between selected practice characteristics, patient engagement, and patient-reported outcomes of care. Cross-sectional multilevel observational study of 16 randomly selected practices in two large accountable care organizations (ACOs). Patients with diabetes and/or cardiovascular disease (CVD) who met study eligibility criteria (n = 4368) and received care in 2014 were randomly selected to complete a patient activation and PRO survey (51% response rate; n = 2176). Primary care team members of the 16 practices completed surveys that assessed practice culture, relational coordination, and teamwork (86% response rate; n = 411). Patient-reported outcomes included depression (PHQ-4), physical functioning (PROMIS SF12a), and social functioning (PROMIS SF8a), the Patient Assessment of Chronic Illness Care instrument (PACIC-11), and the Patient Activation Measure instrument (PAM-13). Patient-level covariates included patient age, gender, education, insurance coverage, limited English language proficiency, blood pressure, HbA1c, LDL-cholesterol, and disease comorbidity burden. For each of the 16 practices, patient-centered culture and the degree of relational coordination among team members were measured using a clinician and staff survey. The implementation of shared decision-making activities in each practice was assessed using an operational leader survey. Having a patient-centered culture was positively associated with fewer depression symptoms (odds ratio [OR] = 1.51; confidence interval [CI] 1.04, 2.19) and better physical function scores (OR = 1.85; CI 1.25, 2.73). Patient activation was positively associated with fewer

  16. Systematic lymphadenectomy for survival in patients with endometrial cancer: a meta-analysis.

    Science.gov (United States)

    Kim, Hee Seung; Suh, Dong Hoon; Kim, Mi-Kyung; Chung, Hyun Hoon; Park, Noh Hyun; Song, Yong Sang

    2012-05-01

    The efficacy of systematic lymphadenectomy is controversial for improving overall survival in patients with endometrial cancer. Thus, we performed a meta-analysis comparing the efficacy for overall survival between systematic and unsystematic lymphadenectomies. After an extensive literature search between January 2000 and August 2010, we analyzed nine studies (two randomized controlled trials and seven observational studies) involving 16 995 patients with endometrial cancer. Systematic versus unsystematic lymphadenectomy was defined using two criteria: removal of ≥10-11 versus ≤10-11 lymph nodes; systematic dissection of lymphatic tissues versus no lymphadenectomy other than suspicious lymph nodes. In all studies, systematic lymphadenectomy improved overall survival, compared with unsystematic lymphadenectomy (hazard ratio, 0.89; 95% confidence interval, 0.82-0.97), whereas its efficacy was not shown in two randomized controlled trials (hazard ratio, 1.05; 95% confidence interval, 0.84-1.31). Removal of ≥10-11 lymph nodes improved overall survival, compared with that of ≤10-11 lymph nodes (hazard ratio, 0.88; 95% confidence interval, 0.81-0.97) in spite of no difference in overall survival between systematic dissection of lymphatic tissues and no lymphadenectomy other than suspicious lymph nodes (hazard ratio, 0.94; 95% confidence interval, 0.77-1.15). Furthermore, systematic lymphadenectomy increased overall survival in patients with intermediate- or high-risk endometrial cancer (hazard ratio, 0.77; 95% confidence interval, 0.70-0.86) in spite of no efficacy in those with low-risk endometrial cancer (hazard ratio, 1.14; 95% confidence interval, 0.87-1.49). These findings suggest that the efficacy of systematic lymphadenectomy, defined as removal of more than about 10 lymph nodes, is limited for improving overall survival in patients with low-risk endometrial cancer, whereas it is efficient to increase overall survival in patients with intermediate- or high

  17. Correlating transcriptional networks to breast cancer survival: a large-scale coexpression analysis.

    Science.gov (United States)

    Clarke, Colin; Madden, Stephen F; Doolan, Padraig; Aherne, Sinead T; Joyce, Helena; O'Driscoll, Lorraine; Gallagher, William M; Hennessy, Bryan T; Moriarty, Michael; Crown, John; Kennedy, Susan; Clynes, Martin

    2013-10-01

    Weighted gene coexpression network analysis (WGCNA) is a powerful 'guilt-by-association'-based method to extract coexpressed groups of genes from large heterogeneous messenger RNA expression data sets. We have utilized WGCNA to identify 11 coregulated gene clusters across 2342 breast cancer samples from 13 microarray-based gene expression studies. A number of these transcriptional modules were found to be correlated to clinicopathological variables (e.g. tumor grade), survival endpoints for breast cancer as a whole (disease-free survival, distant disease-free survival and overall survival) and also its molecular subtypes (luminal A, luminal B, HER2+ and basal-like). Examples of findings arising from this work include the identification of a cluster of proliferation-related genes that when upregulated correlated to increased tumor grade and were associated with poor survival in general. The prognostic potential of novel genes, for example, ubiquitin-conjugating enzyme E2S (UBE2S) within this group was confirmed in an independent data set. In addition, gene clusters were also associated with survival for breast cancer molecular subtypes including a cluster of genes that was found to correlate with prognosis exclusively for basal-like breast cancer. The upregulation of several single genes within this coexpression cluster, for example, the potassium channel, subfamily K, member 5 (KCNK5) was associated with poor outcome for the basal-like molecular subtype. We have developed an online database to allow user-friendly access to the coexpression patterns and the survival analysis outputs uncovered in this study (available at http://glados.ucd.ie/Coexpression/).

  18. TP53 Mutations and Survival in Osteosarcoma Patients: A Meta-Analysis of Published Data

    Directory of Open Access Journals (Sweden)

    Zhe Chen

    2016-01-01

    Full Text Available Several research groups have examined the association between TP53 mutations and prognosis in human osteosarcoma. However, the results were controversial. The purpose of this study was to evaluate the prognostic value of TP53 mutations in osteosarcoma patients. A meta-analysis was conducted with all eligible studies which quantitatively evaluated the relationship between TP53 mutations and clinical outcome of osteosarcoma patients. Eight studies with a total of 210 patients with osteosarcoma were included in this meta-analysis. The risk ratio (RR with a 95% confidence interval (95% CI was calculated to assess the effect of TP53 mutations on 2-year overall survival. The quantitative synthesis of 8 published studies showed that TP53 mutations were associated with 2-year overall survival in osteosarcoma patients. These data suggested that TP53 mutations had an unfavorable impact on 2-year overall survival when compared to the counterparts with wild type (WT TP53 (RR: 1.79; 95% CI: 1.12 to 2.84; P=0.01; I2=0%. There was no between-study heterogeneity. TP53 mutations are an effective prognostic marker for survival of patients with osteosarcoma. However, further large-scale prospective trials should be performed to clarify the prognostic value of TP53 mutations on 3- or 5-year survival in osteosarcoma patients.

  19. TP53 Mutations and Survival in Osteosarcoma Patients: A Meta-Analysis of Published Data.

    Science.gov (United States)

    Chen, Zhe; Guo, Jiayi; Zhang, Kun; Guo, Yanxing

    2016-01-01

    Several research groups have examined the association between TP53 mutations and prognosis in human osteosarcoma. However, the results were controversial. The purpose of this study was to evaluate the prognostic value of TP53 mutations in osteosarcoma patients. A meta-analysis was conducted with all eligible studies which quantitatively evaluated the relationship between TP53 mutations and clinical outcome of osteosarcoma patients. Eight studies with a total of 210 patients with osteosarcoma were included in this meta-analysis. The risk ratio (RR) with a 95% confidence interval (95% CI) was calculated to assess the effect of TP53 mutations on 2-year overall survival. The quantitative synthesis of 8 published studies showed that TP53 mutations were associated with 2-year overall survival in osteosarcoma patients. These data suggested that TP53 mutations had an unfavorable impact on 2-year overall survival when compared to the counterparts with wild type (WT) TP53 (RR: 1.79; 95% CI: 1.12 to 2.84; P = 0.01; I (2) = 0%). There was no between-study heterogeneity. TP53 mutations are an effective prognostic marker for survival of patients with osteosarcoma. However, further large-scale prospective trials should be performed to clarify the prognostic value of TP53 mutations on 3- or 5-year survival in osteosarcoma patients.

  20. [Applying multilevel models in evaluation of bioequivalence (I)].

    Science.gov (United States)

    Liu, Qiao-lan; Shen, Zhuo-zhi; Chen, Feng; Li, Xiao-song; Yang, Min

    2009-12-01

    This study aims to explore the application value of multilevel models for bioequivalence evaluation. Using a real example of 2 x 4 cross-over experimental design in evaluating bioequivalence of antihypertensive drug, this paper explores complex variance components corresponding to criteria statistics in existing methods recommended by FDA but obtained in multilevel models analysis. Results are compared with those from FDA standard Method of Moments, specifically on the feasibility and applicability of multilevel models in directly assessing the bioequivalence (ABE), the population bioequivalence (PBE) and the individual bioequivalence (IBE). When measuring ln (AUC), results from all variance components of the test and reference groups such as total variance (sigma(TT)(2) and sigma(TR)(2)), between-subject variance (sigma(BT)(2) and sigma(BR)(2)) and within-subject variance (sigma(WT)(2) and sigma(WR)(2)) estimated by simple 2-level models are very close to those that using the FDA Method of Moments. In practice, bioequivalence evaluation can be carried out directly by multilevel models, or by FDA criteria, based on variance components estimated from multilevel models. Both approaches produce consistent results. Multilevel models can be used to evaluate bioequivalence in cross-over test design. Compared to FDA methods, this one is more flexible in decomposing total variance into sub components in order to evaluate the ABE, PBE and IBE. Multilevel model provides a new way into the practice of bioequivalence evaluation.

  1. When will I succeed in my first-year diploma? Survival analysis in Dutch higher education

    NARCIS (Netherlands)

    Bruinsma, Marjon; Jansen, Ellen P. W. A.

    2009-01-01

    The goal of this study was to illustrate survival analysis with higher education data and gain insight into a limited set of factors that predict when students passed their first-year examination at a Dutch university. Study participants consisted of 565 first-year students in four departments. Data

  2. When will I succeed in my first-year diploma? Survival analysis in Dutch higher education

    NARCIS (Netherlands)

    Bruinsma, Marjon; Jansen, Ellen P. W. A.

    2009-01-01

    The goal of this study was to illustrate survival analysis with higher education data and gain insight into a limited set of factors that predict when students passed their first-year examination at a Dutch university. Study participants consisted of 565 first-year students in four departments. Data

  3. Predicting Secondary School Dropout among South African Adolescents: A Survival Analysis Approach

    Science.gov (United States)

    Weybright, Elizabeth H.; Caldwell, Linda L.; Xie, Hui; Wegner, Lisa; Smith, Edward A.

    2017-01-01

    Education is one of the strongest predictors of health worldwide. In South Africa, school dropout is a crisis where by Grade 12, only 52% of the age appropriate population remain enrolled. Survival analysis was used to identify the risk of dropping out of secondary school for male and female adolescents and examine the influence of substance use…

  4. Effect of obesity on survival of women with breast cancer: systematic review and meta-analysis.

    Science.gov (United States)

    Protani, Melinda; Coory, Michael; Martin, Jennifer H

    2010-10-01

    Obesity is a risk factor for the development of new cases of breast cancer and also affects survival in women who have already been diagnosed with breast cancer. Early studies of obesity and breast cancer survival have been summarised in two meta-analyses, but the latest of these only included studies that recruited women diagnosed as recently as 1991. The primary aim of this study was to conduct a meta-analysis that included the more recent studies. A systematic search of MEDLINE, EMBASE and CINAHL was conducted to identify original data evaluating the effects of obesity on survival in newly diagnosed breast cancer patients. Adjusted hazard ratios (HR) from individual studies were pooled using a random effects model. A series of pre-specified sensitivity analyses were conducted on factors such as overall versus breast cancer survival and treatment versus observational cohort. The meta-analysis included 43 studies that enrolled women diagnosed with breast cancer between 1963 and 2005. Sample size ranged from 100 to 424168 (median 1192). The meta-analysis showed poorer survival among obese compared with non-obese women with breast cancer, which was similar for overall (HR = 1.33; 95% confidence interval (CI): 1.21, 1.47) and breast cancer specific survival (HR = 1.33; 95% CI: 1.19, 1.50). The survival differential varied only slightly, depending on whether body mass index (1.33; 1.21, 1.47) or waist-hip ratio (1.31; 1.08, 1.58) was used as the measure of obesity. There were larger differences by whether the woman was pre-menopausal (1.47) or post-menopausal (1.22); whether the cohort included women diagnosed before (1.31) or after 1995 (1.49); or whether the women were in a treatment (1.22) or observational cohort (1.36), but none of the differences were statistically significant. Women with breast cancer, who are obese, have poorer survival than women with breast cancer, who are not obese. However, no study has elucidated the causal mechanism and there is currently

  5. Marital status and survival in pancreatic cancer patients: a SEER based analysis.

    Directory of Open Access Journals (Sweden)

    Michael Baine

    Full Text Available BACKGROUND: Recent findings suggest that marital status affects survival in patients with different types of cancer. However, its role in the survival of patients with pancreatic ductal adenocarcinoma is unknown. In this study, we investigated whether there was an association between marital status and overall survival (OS in patients with pancreatic ductal adenocarcinoma (PDAC. METHODS: Adult patients diagnosed with PDAC between 1998 and 2003 with known marital statuses were identified from the Surveillance, Epidemiology, and End Results registry of the National Cancer Institute. OS for these patients was plotted using the Kaplan-Meier method. Comparative risks of mortality were evaluated by using univariate and multivariate-adjusted Cox regression models. RESULTS: Using Kaplan-Meier analysis, we found that the median overall survival of patients was 4 months and 3 months (p<0.001 for married and unmarried patients, respectively. Subgroup analysis on patients with cancer-directed surgery showed that the median survival was 16 months and 13 months (P<0.0005 for married and unmarried groups, respectively. Multivariate analysis adjusting for age, race, sex, stage, year of diagnosis, radiation therapy and cancer-directed surgery showed that patients who were married at the time of diagnosis had a significantly decreased risk of death at both 2 months (15% risk reduction and 3 years (13% risk reduction post diagnosis. CONCLUSIONS: Marital status is an independent prognostic factor of both perioperative and long-term survival in patients with PDAC. This observation may suggest a suboptimally met psychosocial need among PDAC patients that is partially fulfilled by the support system provided by marriage.

  6. Application of Survival Analysis and Multistate Modeling to Understand Animal Behavior: Examples from Guide Dogs

    Science.gov (United States)

    Asher, Lucy; Harvey, Naomi D.; Green, Martin; England, Gary C. W.

    2017-01-01

    Epidemiology is the study of patterns of health-related states or events in populations. Statistical models developed for epidemiology could be usefully applied to behavioral states or events. The aim of this study is to present the application of epidemiological statistics to understand animal behavior where discrete outcomes are of interest, using data from guide dogs to illustrate. Specifically, survival analysis and multistate modeling are applied to data on guide dogs comparing dogs that completed training and qualified as a guide dog, to those that were withdrawn from the training program. Survival analysis allows the time to (or between) a binary event(s) and the probability of the event occurring at or beyond a specified time point. Survival analysis, using a Cox proportional hazards model, was used to examine the time taken to withdraw a dog from training. Sex, breed, and other factors affected time to withdrawal. Bitches were withdrawn faster than dogs, Labradors were withdrawn faster, and Labrador × Golden Retrievers slower, than Golden Retriever × Labradors; and dogs not bred by Guide Dogs were withdrawn faster than those bred by Guide Dogs. Multistate modeling (MSM) can be used as an extension of survival analysis to incorporate more than two discrete events or states. Multistate models were used to investigate transitions between states of training to qualification as a guide dog or behavioral withdrawal, and from qualification as a guide dog to behavioral withdrawal. Sex, breed (with purebred Labradors and Golden retrievers differing from F1 crosses), and bred by Guide Dogs or not, effected movements between states. We postulate that survival analysis and MSM could be applied to a wide range of behavioral data and key examples are provided. PMID:28804710

  7. Application of Survival Analysis and Multistate Modeling to Understand Animal Behavior: Examples from Guide Dogs.

    Science.gov (United States)

    Asher, Lucy; Harvey, Naomi D; Green, Martin; England, Gary C W

    2017-01-01

    Epidemiology is the study of patterns of health-related states or events in populations. Statistical models developed for epidemiology could be usefully applied to behavioral states or events. The aim of this study is to present the application of epidemiological statistics to understand animal behavior where discrete outcomes are of interest, using data from guide dogs to illustrate. Specifically, survival analysis and multistate modeling are applied to data on guide dogs comparing dogs that completed training and qualified as a guide dog, to those that were withdrawn from the training program. Survival analysis allows the time to (or between) a binary event(s) and the probability of the event occurring at or beyond a specified time point. Survival analysis, using a Cox proportional hazards model, was used to examine the time taken to withdraw a dog from training. Sex, breed, and other factors affected time to withdrawal. Bitches were withdrawn faster than dogs, Labradors were withdrawn faster, and Labrador × Golden Retrievers slower, than Golden Retriever × Labradors; and dogs not bred by Guide Dogs were withdrawn faster than those bred by Guide Dogs. Multistate modeling (MSM) can be used as an extension of survival analysis to incorporate more than two discrete events or states. Multistate models were used to investigate transitions between states of training to qualification as a guide dog or behavioral withdrawal, and from qualification as a guide dog to behavioral withdrawal. Sex, breed (with purebred Labradors and Golden retrievers differing from F1 crosses), and bred by Guide Dogs or not, effected movements between states. We postulate that survival analysis and MSM could be applied to a wide range of behavioral data and key examples are provided.

  8. Mechanisms and mediation in survival analysis: towards an integrated analytical framework.

    LENUS (Irish Health Repository)

    Haase, Trutz

    2016-02-29

    A wide-ranging debate has taken place in recent years on mediation analysis and causal modelling, raising profound theoretical, philosophical and methodological questions. The authors build on the results of these discussions to work towards an integrated approach to the analysis of research questions that situate survival outcomes in relation to complex causal pathways with multiple mediators. The background to this contribution is the increasingly urgent need for policy-relevant research on the nature of inequalities in health and healthcare.

  9. Survival Analysis of 1,742 Patients with Stage IV Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Hong PENG

    2011-04-01

    Full Text Available Background and objective At present non-small cell lung cancer (NSCLC is still the leading cause of death induced by cancer. The aim of this study is to investigate the prognostic factors of advanced NSCLC. Methods Total 1,742 cases of stage IV NSCLC data from Jan 4, 2000 to Dec 25, 2008 in Shanghai Chest Hospital were collected, confirmed by pathological examinations. Analysis was made to observe the impact of treatment on prognosis in gender, age, smoking history, pathology, classification, clinical TNM stage. Survival rate, survival difference were evaluated by Kaplan-Meire method and Logrank test respectively. The prognosis were analyzed by Cox multivariate regression. Results The median survival time of 1,742 patients was 10.0 months (9.5 months-10.5 months. One, two, three, four, and five-year survival rates were 44%, 22%, 13%, 9%, 6% respectively. The median survivals of single or multiple metastasis were 11 months vs 7 months (P < 0.001. Survival time were different in metastasic organs, with the median survival time as follows: lung for about 12 months (11.0 months-12.9 months, bone for 9 months (8.3 months-9.6 months, brain for 8 months (6.8 months-9.1 months, liver, adrenal gland, distannt lymph node metastasis for 5 months (3.8 months-6.1 months, and subcutaneous for 3 months (1.7 months-4.3 months. The median survival times of adenocarcinoma (n=1,086, 62% and squamous cell carcinoma cases (n=305, 17.5% were 12 months vs 8 months (P < 0.001. The median survival time of chemotherapy and best supportive care were 11 months vs 6 months (P < 0.001; the median survival times of with and without radiotherapy were 11 months vs 9 months (P=0.017. Conclusion Gender, age, gross type, pathological type, clinical T stage, N stage, numbers of metastatic organ, smoking history, treatment of advanced non-small cell lung cancer were independent prognostic factors.

  10. Analysis of factors affecting survival in dogs with aortic body tumors.

    Science.gov (United States)

    Ehrhart, Nicole; Ehrhart, E J; Willis, Jennifer; Sisson, David; Constable, Peter; Greenfield, Cathy; Manfra-Maretta, Sandra; Hintermeister, John

    2002-01-01

    To evaluate the effect of perioperative and operative variables on survival time in dogs with aortic body tumors. Retrospective study. Twenty-four client-owned dogs with histologically confirmed aortic body tumor. Seventy-eight patient records of dogs seen at the University of Illinois Veterinary Teaching Hospital between 1989 and 1999 with a diagnosis of a heart-base mass were reviewed. Dogs without histologic conformation of an aortic body tumor were excluded. Age; sex; breed; the presence of pleural effusion, pericardial effusion, or abdominal effusion; evidence of cardiac arrhythmias; evidence of distant metastasis; treatment with pericardectomy; treatment with chemotherapy; and time from diagnosis until euthanasia or death were recorded on a spreadsheet. Cox proportional-hazard ratios were used to calculate the relationship of risk variables to survival time. Median survival time was determined using life-table analysis. Twenty-four dogs met the criteria for inclusion in the study. The median age of dogs with aortic body tumors was 9 years. All dogs had a surgical biopsy performed. Fourteen dogs had a pericardectomy at the time of the biopsy procedure. Of all factors analyzed, only treatment with pericardectomy had a significant influence on survival (P =.0029). Dogs that had pericardectomy survived longer (median survival, 730 days; range, 1-1,621 days) compared with dogs that did not have pericardectomy (median survival, 42 days; range, 1-180 days). This finding was independent of the presence or absence of pericardial effusion at the time of surgery. Dogs that are diagnosed with aortic body tumors may benefit from a pericardectomy at the time of surgical biopsy. Copyright 2002 by The American College of Veterinary Surgeons

  11. Structural optimization of wind turbine rotor blades by multilevel sectional/multibody/3D-FEM analysis

    DEFF Research Database (Denmark)

    Bottasso, C. L.; Campagnolo, F.; Croce, A.

    2014-01-01

    level. At first, a "coarse"-level constrained design optimization is performed by using a 1D spatial geometrically exact beam model for aero-servo-elastic multibody analysis and load calculation, integrated with a 2D FEM cross sectional model for stress/strain analysis, and the evaluation of the 1D...

  12. The Internationalization of Canadian University Research: A Global Higher Education Matrix Analysis of Multi-Level Governance

    Science.gov (United States)

    Jones, Glen A.; Oleksiyenko, Anatoly

    2011-01-01

    To date, much of the research on internationalization and globalization of higher education has focused on the institution or higher education system as the unit of analysis. Institution based studies have focused on the analysis of institutional practices and policies designed to further internationalization. System-level studies focus on state…

  13. The L(1/2) regularization approach for survival analysis in the accelerated failure time model.

    Science.gov (United States)

    Chai, Hua; Liang, Yong; Liu, Xiao-Ying

    2015-09-01

    The analysis of high-dimensional and low-sample size microarray data for survival analysis of cancer patients is an important problem. It is a huge challenge to select the significantly relevant bio-marks from microarray gene expression datasets, in which the number of genes is far more than the size of samples. In this article, we develop a robust prediction approach for survival time of patient by a L(1/2) regularization estimator with the accelerated failure time (AFT) model. The L(1/2) regularization could be seen as a typical delegate of L(q)(0regularization methods and it has shown many attractive features. In order to optimize the problem of the relevant gene selection in high-dimensional biological data, we implemented the L(1/2) regularized AFT model by the coordinate descent algorithm with a renewed half thresholding operator. The results of the simulation experiment showed that we could obtain more accurate and sparse predictor for survival analysis by the L(1/2) regularized AFT model compared with other L1 type regularization methods. The proposed procedures are applied to five real DNA microarray datasets to efficiently predict the survival time of patient based on a set of clinical prognostic factors and gene signatures.

  14. Multimodality treatment of brain metastases: an institutional survival analysis of 275 patients

    Directory of Open Access Journals (Sweden)

    Demakas John J

    2011-07-01

    Full Text Available Abstract Background Whole brain radiation therapy (WBRT, surgical resection, stereotactic radiosurgery (SRS, and combinations of the three modalities are used in the management of patients with metastatic brain tumors. We present the previously unreported survival outcomes of 275 patients treated for newly diagnosed brain metastases at Cancer Care Northwest and Gamma Knife of Spokane between 1998 and 2008. Methods The effects treatment regimen, age, Eastern Cooperative Oncology Group-Performance Status (ECOG-PS, primary tumor histology, number of brain metastases, and total volume of brain metastases have on patient overall survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival curves, Andersen 95% confidence intervals, approximate confidence intervals for log hazard-ratios, and multivariate Cox proportional hazard models. Results The median clinical follow up time was 7.2 months. On multivariate analysis, survival statistically favored patients treated with SRS alone when compared to patients treated with WBRT alone (p Conclusions In our analysis, patients benefited from a combined modality treatment approach and physicians must consider patient age, performance status, and primary tumor histology when recommending specific treatments regimens.

  15. [Childhood cancer: a comparative analysis of incidence, mortality, and survival in Goiania (Brazil) and other countries].

    Science.gov (United States)

    Braga, Patrícia Emília; Latorre Md, Maria do Rosário Dias de Oliveira; Curado, Maria Paula

    2002-01-01

    Analysis of cancer incidence, mortality, and survival rates can yield geographic and temporal trends that are useful for planning and evaluating health interventions. This article reviews cancer incidence and mortality rates and respective trends around the world in children under 15 years old, as well as their 5-year survival rates in developed and developing countries. We conclude that even though increasing or stable childhood cancer incidence rates and decreasing mortality rates have been observed in developed countries, the trends remain unknown in developing countries. Data from the city of Goiania, Brazil, show stable childhood cancer incidence and mortality rates. Five-year survival rates (48%) in Goiania are similar to those seen in underdeveloped regions and lower than those reported in developed countries (64-70%).

  16. Total Ankle Replacement Survival Rates Based on Kaplan-Meier Survival Analysis of National Joint Registry Data.

    Science.gov (United States)

    Bartel, Annette F P; Roukis, Thomas S

    2015-10-01

    National joint registry data provides unique information about primary total ankle replacement (TAR) survival. We sought to recreate survival curves among published national joint registry data sets using the Kaplan-Meier estimator. Overall, 5152 primary and 591 TAR revisions were included over a 2- to 13-year period with prosthesis survival for all national joint registries of 0.94 at 2-years, 0.87 at 5-years and 0.81 at 10-years. National joint registry datasets should strive for completion of data presentation including revision definitions, modes and time of failure, and patients lost to follow-up or death for complete accuracy of the Kaplan-Meier estimator.

  17. Evaluation of survival stow position and stability analysis for heliostat under strong wind

    Institute of Scientific and Technical Information of China (English)

    冯煜; 陈小安; 单文桃

    2016-01-01

    Heliostats are sensitive to the wind load, thus as a key indicator, the study on the static and dynamic stability bearing capacity for heliostats is very important. In this work, a numerical wind tunnel was established to calculate the wind load coefficients in various survival stow positions. In order to explore the best survival stow position for the heliostat under the strong wind, eigenvalue buckling analysis method was introduced to predict the critical wind load theoretically. Considering the impact of the nonlinearity and initial geometrical imperfection, the nonlinear post-buckling behaviors of the heliostat were investigated by load−displacement curves in the full equilibrium process. Eventually, combining B-R criterion with equivalent displacement principle the dynamic critical wind speed and load amplitude coefficient were evaluated. The results show that the determination for the best survival stow position is too hasty just by the wind load coefficients. The geometric nonlinearity has a great effect on the stability bearing capacity of the heliostat, while the effects of the material nonlinearity and initial geometrical imperfection are relatively small. And the heliostat is insensitive to the initial geometrical imperfection. In addition, the heliostat has the highest safety factor for wind-resistant performance in the stow position of 90−90 which can be taken as the best survival stow position. In this case, the extreme survival wind speeds for the static and dynamic stability are 150 m/s and 36 m/s, respectively.

  18. Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): III. juvenile survival.

    Science.gov (United States)

    Isberg, S R; Thomson, P C; Nicholas, F W; Barker, S G; Moran, C

    2006-02-01

    Mortality records of 1302 juvenile crocodiles were available for analysis. Crocodiles that were slaughtered during this study were treated as censored (n = 2151). Additionally, records from animals that had neither died nor been slaughtered, i.e. were still alive in the production system (n = 1582), were censored at the last date of data collection. There were a total of 3733 censored records. The data were all full-sib records from 29 parental pairs from Janamba Croc Farm (Northern Territory, Australia), collected over nine consecutive years. Data were analysed using an extension of Cox's proportional hazards model to include frailty (random) terms to account for genetic effects. Heritability of log survival time for juvenile crocodile survival was 0.15 (SE 0.04). The probability of a juvenile crocodile surviving to day 400 was estimated to be only 51%. These results are the first to quantify juvenile survival in a captive breeding situation. Also, this is the first heritability estimate of crocodile survival and is a fundamental element in the development of a genetic improvement programme.

  19. Basic Function Analysis of Transferring System on Multi-level Capital Market%多层次资本市场转板制度基本功能分析

    Institute of Scientific and Technical Information of China (English)

    刘国胜

    2014-01-01

    我国资本市场多层次建设已经初具规模,层次之间的互动性问题开始凸显,转板制度构建已经刻不容缓,但人们似乎并不理解转板制度对多层次资本市场建设的重要价值。多层次资本市场转板制度及其基本功能,对于帮助人们理解和重视多层次资本市场结构下转板制度建设具有重要作用。%Our construction on multi level capital market has formed a basic frame. Problems of interaction between the levels are highlighting. Construction of transferring system has not been delayed. But people don ’t seem to understand important value of transfer-ring system construction of multi-level capital market. By analysis of basic function of the multi-level capital market, we pay attention to transferring system on the multi-level capital market structure.

  20. DAKOTA : a multilevel parallel object-oriented framework for design optimization, parameter estimation, uncertainty quantification, and sensitivity analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Michael Scott; Vigil, Dena M.; Dalbey, Keith R.; Bohnhoff, William J.; Adams, Brian M.; Swiler, Laura Painton; Lefantzi, Sophia (Sandia National Laboratories, Livermore, CA); Hough, Patricia Diane (Sandia National Laboratories, Livermore, CA); Eddy, John P.

    2011-12-01

    The DAKOTA (Design Analysis Kit for Optimization and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes and iterative analysis methods. DAKOTA contains algorithms for optimization with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, and stochastic expansion methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as surrogate-based optimization, mixed integer nonlinear programming, or optimization under uncertainty. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a theoretical manual for selected algorithms implemented within the DAKOTA software. It is not intended as a comprehensive theoretical treatment, since a number of existing texts cover general optimization theory, statistical analysis, and other introductory topics. Rather, this manual is intended to summarize a set of DAKOTA-related research publications in the areas of surrogate-based optimization, uncertainty quantification, and optimization under uncertainty that provide the foundation for many of DAKOTA's iterative analysis capabilities.