A Bootstrap Generalization of Modified Parallel Analysis for IRT Dimensionality Assessment

ERIC Educational Resources Information Center

Finch, Holmes; Monahan, Patrick

2008-01-01

This article introduces a bootstrap generalization to the Modified Parallel Analysis (MPA) method of test dimensionality assessment using factor analysis. This methodology, based on the use of Marginal Maximum Likelihood nonlinear factor analysis, provides for the calculation of a test statistic based on a parametric bootstrap using the MPA…

The Determinants of Place of Death: An Evidence-Based Analysis

PubMed Central

Costa, V

2014-01-01

Background According to a conceptual model described in this analysis, place of death is determined by an interplay of factors associated with the illness, the individual, and the environment. Objectives Our objective was to evaluate the determinants of place of death for adult patients who have been diagnosed with an advanced, life-limiting condition and are not expected to stabilize or improve. Data Sources A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), and EBM Reviews, for studies published from January 1, 2004, to September 24, 2013. Review Methods Different places of death are considered in this analysis—home, nursing home, inpatient hospice, and inpatient palliative care unit, compared with hospital. We selected factors to evaluate from a list of possible predictors—i.e., determinants—of death. We extracted the adjusted odds ratios and 95% confidence intervals of each determinant, performed a meta-analysis if appropriate, and conducted a stratified analysis if substantial heterogeneity was observed. Results From a literature search yielding 5,899 citations, we included 2 systematic reviews and 29 observational studies. Factors that increased the likelihood of home death included multidisciplinary home palliative care, patient preference, having an informal caregiver, and the caregiver's ability to cope. Factors increasing the likelihood of a nursing home death included the availability of palliative care in the nursing home and the existence of advance directives. A cancer diagnosis and the involvement of home care services increased the likelihood of dying in an inpatient palliative care unit. A cancer diagnosis and a longer time between referral to palliative care and death increased the likelihood of inpatient hospice death. The quality of the evidence was considered low. Limitations Our results are based on those of retrospective observational studies. Conclusions The results obtained were consistent with previously published systematic reviews. The analysis identified several factors that are associated with place of death. PMID:26351550

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

PubMed

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

2015-06-01

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 coefficient (ICC) and estimation method; maximum likelihood estimation with robust chi-squares and standard errors and Bayesian estimation, on the convergence rate are investigated. The other variables of interest were rate of inadmissible solutions and the relative parameter and standard error bias on the between level. The results showed that inadmissible solutions were obtained when there was between level collinearity and the estimation method was maximum likelihood. In the within level multicollinearity condition, all of the solutions were admissible but the bias values were higher compared with the between level collinearity condition. Bayesian estimation appeared to be robust in obtaining admissible parameters but the relative bias was higher than for maximum likelihood estimation. Finally, as expected, high ICC produced less biased results compared to medium ICC conditions.

Source and Message Factors in Persuasion: A Reply to Stiff's Critique of the Elaboration Likelihood Model.

ERIC Educational Resources Information Center

Petty, Richard E.; And Others

1987-01-01

Answers James Stiff's criticism of the Elaboration Likelihood Model (ELM) of persuasion. Corrects certain misperceptions of the ELM and criticizes Stiff's meta-analysis that compares ELM predictions with those derived from Kahneman's elastic capacity model. Argues that Stiff's presentation of the ELM and the conclusions he draws based on the data…

Reducing weapon-carrying among urban American Indian young people.

PubMed

Bearinger, Linda H; Pettingell, Sandra L; Resnick, Michael D; Potthoff, Sandra J

2010-07-01

To examine the likelihood of weapon-carrying among urban American Indian young people, given the presence of salient risk and protective factors. The study used data from a confidential, self-report Urban Indian Youth Health Survey with 200 forced-choice items examining risk and protective factors and social, contextual, and demographic information. Between 1995 and 1998, 569 American Indian youths, aged 9-15 years, completed surveys administered in public schools and an after-school program. Using logistic regression, probability profiles compared the likelihood of weapon-carrying, given the combinations of salient risk and protective factors. In the final models, weapon-carrying was associated significantly with one risk factor (substance use) and two protective factors (school connectedness, perceiving peers as having prosocial behavior attitudes/norms). With one risk factor and two protective factors, in various combinations in the models, the likelihood of weapon carrying ranged from 4% (with two protective factors and no risk factor in the model) to 80% of youth (with the risk factor and no protective factors in the model). Even in the presence of the risk factor, the two protective factors decreased the likelihood of weapon-carrying to 25%. This analysis highlights the importance of protective factors in comprehensive assessments and interventions for vulnerable youth. In that the risk factor and two protective factors significantly related to weapon-carrying are amenable to intervention at both individual and population-focused levels, study findings offer a guide for prioritizing strategies for decreasing weapon-carrying among urban American Indian young people. Copyright (c) 2010 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Species delimitation using Bayes factors: simulations and application to the Sceloporus scalaris species group (Squamata: Phrynosomatidae).

PubMed

Grummer, Jared A; Bryson, Robert W; Reeder, Tod W

2014-03-01

Current molecular methods of species delimitation are limited by the types of species delimitation models and scenarios that can be tested. Bayes factors allow for more flexibility in testing non-nested species delimitation models and hypotheses of individual assignment to alternative lineages. Here, we examined the efficacy of Bayes factors in delimiting species through simulations and empirical data from the Sceloporus scalaris species group. Marginal-likelihood scores of competing species delimitation models, from which Bayes factor values were compared, were estimated with four different methods: harmonic mean estimation (HME), smoothed harmonic mean estimation (sHME), path-sampling/thermodynamic integration (PS), and stepping-stone (SS) analysis. We also performed model selection using a posterior simulation-based analog of the Akaike information criterion through Markov chain Monte Carlo analysis (AICM). Bayes factor species delimitation results from the empirical data were then compared with results from the reversible-jump MCMC (rjMCMC) coalescent-based species delimitation method Bayesian Phylogenetics and Phylogeography (BP&P). Simulation results show that HME and sHME perform poorly compared with PS and SS marginal-likelihood estimators when identifying the true species delimitation model. Furthermore, Bayes factor delimitation (BFD) of species showed improved performance when species limits are tested by reassigning individuals between species, as opposed to either lumping or splitting lineages. In the empirical data, BFD through PS and SS analyses, as well as the rjMCMC method, each provide support for the recognition of all scalaris group taxa as independent evolutionary lineages. Bayes factor species delimitation and BP&P also support the recognition of three previously undescribed lineages. In both simulated and empirical data sets, harmonic and smoothed harmonic mean marginal-likelihood estimators provided much higher marginal-likelihood estimates than PS and SS estimators. The AICM displayed poor repeatability in both simulated and empirical data sets, and produced inconsistent model rankings across replicate runs with the empirical data. Our results suggest that species delimitation through the use of Bayes factors with marginal-likelihood estimates via PS or SS analyses provide a useful and complementary alternative to existing species delimitation methods.

Factors associated with the hospital admission of consumer product-related injuries treated in U.S. hospital emergency departments.

PubMed

Schroeder, Thomas J; Rodgers, Gregory B

2013-10-01

While unintentional injuries and hazard patterns involving consumer products have been studied extensively in recent years, little attention has focused on the characteristics of those who are hospitalized after treatment in emergency departments, as opposed to those treated and released. This study quantifies the impact of the age and sex of the injury victims, and other factors, on the likelihood of hospitalization. The analysis focuses on consumer product injuries, and was based on approximately 400,000 injury cases reported through the U.S. Consumer Product Safety Commission's National Electronic Injury Surveillance System, a national probability sample of U.S. hospital emergency departments. Logistic regression was used to quantify the factors associated with the likelihood of hospitalization. The analysis suggests a smooth U-shaped relationship between the age of the victim and the likelihood of hospitalization, declining from about 3.4% for children under age 5 years to 1.9% for 15-24 year-olds, but then rising to more than 25% for those ages 75 years and older. The likelihood of hospitalization was also significantly affected by the victim's sex, as well as by the types of products involved, fire involvement, and the size and type of hospital at which the injury was treated. This study shows that the probability of hospitalization is strongly correlated with the characteristics of those who are injured, as well as other factors. Published by Elsevier Ltd.

Factor Analysis with EM Algorithm Never Gives Improper Solutions when Sample Covariance and Initial Parameter Matrices Are Proper

ERIC Educational Resources Information Center

Adachi, Kohei

2013-01-01

Rubin and Thayer ("Psychometrika," 47:69-76, 1982) proposed the EM algorithm for exploratory and confirmatory maximum likelihood factor analysis. In this paper, we prove the following fact: the EM algorithm always gives a proper solution with positive unique variances and factor correlations with absolute values that do not exceed one,…

Exploring the Latent Structure of the Luria Model for the KABC-II at School Age: Further Insights from Confirmatory Factor Analysis

ERIC Educational Resources Information Center

McGill, Ryan J.

2017-01-01

The present study examined the factor structure of the Luria interpretive model for the Kaufman Assessment Battery for Children-Second Edition (KABC-II) with normative sample participants aged 7-18 (N = 2,025) using confirmatory factor analysis with maximum-likelihood estimation. For the eight subtest Luria configuration, an alternative…

Testing students' e-learning via Facebook through Bayesian structural equation modeling.

PubMed

Salarzadeh Jenatabadi, Hashem; Moghavvemi, Sedigheh; Wan Mohamed Radzi, Che Wan Jasimah Bt; Babashamsi, Parastoo; Arashi, Mohammad

2017-01-01

Learning is an intentional activity, with several factors affecting students' intention to use new learning technology. Researchers have investigated technology acceptance in different contexts by developing various theories/models and testing them by a number of means. Although most theories/models developed have been examined through regression or structural equation modeling, Bayesian analysis offers more accurate data analysis results. To address this gap, the unified theory of acceptance and technology use in the context of e-learning via Facebook are re-examined in this study using Bayesian analysis. The data (S1 Data) were collected from 170 students enrolled in a business statistics course at University of Malaya, Malaysia, and tested with the maximum likelihood and Bayesian approaches. The difference between the two methods' results indicates that performance expectancy and hedonic motivation are the strongest factors influencing the intention to use e-learning via Facebook. The Bayesian estimation model exhibited better data fit than the maximum likelihood estimator model. The results of the Bayesian and maximum likelihood estimator approaches are compared and the reasons for the result discrepancy are deliberated.

Testing students’ e-learning via Facebook through Bayesian structural equation modeling

PubMed Central

Moghavvemi, Sedigheh; Wan Mohamed Radzi, Che Wan Jasimah Bt; Babashamsi, Parastoo; Arashi, Mohammad

2017-01-01

Learning is an intentional activity, with several factors affecting students’ intention to use new learning technology. Researchers have investigated technology acceptance in different contexts by developing various theories/models and testing them by a number of means. Although most theories/models developed have been examined through regression or structural equation modeling, Bayesian analysis offers more accurate data analysis results. To address this gap, the unified theory of acceptance and technology use in the context of e-learning via Facebook are re-examined in this study using Bayesian analysis. The data (S1 Data) were collected from 170 students enrolled in a business statistics course at University of Malaya, Malaysia, and tested with the maximum likelihood and Bayesian approaches. The difference between the two methods’ results indicates that performance expectancy and hedonic motivation are the strongest factors influencing the intention to use e-learning via Facebook. The Bayesian estimation model exhibited better data fit than the maximum likelihood estimator model. The results of the Bayesian and maximum likelihood estimator approaches are compared and the reasons for the result discrepancy are deliberated. PMID:28886019

SEPARABLE FACTOR ANALYSIS WITH APPLICATIONS TO MORTALITY DATA

PubMed Central

Fosdick, Bailey K.; Hoff, Peter D.

2014-01-01

Human mortality data sets can be expressed as multiway data arrays, the dimensions of which correspond to categories by which mortality rates are reported, such as age, sex, country and year. Regression models for such data typically assume an independent error distribution or an error model that allows for dependence along at most one or two dimensions of the data array. However, failing to account for other dependencies can lead to inefficient estimates of regression parameters, inaccurate standard errors and poor predictions. An alternative to assuming independent errors is to allow for dependence along each dimension of the array using a separable covariance model. However, the number of parameters in this model increases rapidly with the dimensions of the array and, for many arrays, maximum likelihood estimates of the covariance parameters do not exist. In this paper, we propose a submodel of the separable covariance model that estimates the covariance matrix for each dimension as having factor analytic structure. This model can be viewed as an extension of factor analysis to array-valued data, as it uses a factor model to estimate the covariance along each dimension of the array. We discuss properties of this model as they relate to ordinary factor analysis, describe maximum likelihood and Bayesian estimation methods, and provide a likelihood ratio testing procedure for selecting the factor model ranks. We apply this methodology to the analysis of data from the Human Mortality Database, and show in a cross-validation experiment how it outperforms simpler methods. Additionally, we use this model to impute mortality rates for countries that have no mortality data for several years. Unlike other approaches, our methodology is able to estimate similarities between the mortality rates of countries, time periods and sexes, and use this information to assist with the imputations. PMID:25489353

Structural Equation Analysis of the Wechsler Adult Intelligence Scale-Revised in a Normal Elderly Sample.

ERIC Educational Resources Information Center

Burton, D. Bradley; And Others

1994-01-01

A maximum-likelihood confirmatory factor analysis was performed by applying LISREL VII to the Wechsler Adult Intelligence Scale-Revised results of a normal elderly sample of 225 adults. Results indicate that a three-factor model fits best across all sample combinations. A mild gender effect is discussed. (SLD)

Likelihood-based modification of experimental crystal structure electron density maps

DOEpatents

Terwilliger, Thomas C [Sante Fe, NM

2005-04-16

A maximum-likelihood method for improves an electron density map of an experimental crystal structure. A likelihood of a set of structure factors {F.sub.h } is formed for the experimental crystal structure as (1) the likelihood of having obtained an observed set of structure factors {F.sub.h.sup.OBS } if structure factor set {F.sub.h } was correct, and (2) the likelihood that an electron density map resulting from {F.sub.h } is consistent with selected prior knowledge about the experimental crystal structure. The set of structure factors {F.sub.h } is then adjusted to maximize the likelihood of {F.sub.h } for the experimental crystal structure. An improved electron density map is constructed with the maximized structure factors.

Power and Precision in Confirmatory Factor Analytic Tests of Measurement Invariance

ERIC Educational Resources Information Center

Meade, Adam W.; Bauer, Daniel J.

2007-01-01

This study investigates the effects of sample size, factor overdetermination, and communality on the precision of factor loading estimates and the power of the likelihood ratio test of factorial invariance in multigroup confirmatory factor analysis. Although sample sizes are typically thought to be the primary determinant of precision and power,…

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

PubMed

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. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Quasi-likelihood generalized linear regression analysis of fatality risk data

DOT National Transportation Integrated Search

2009-01-01

Transportation-related fatality risks is a function of many interacting human, vehicle, and environmental factors. Statisitcally valid analysis of such data is challenged both by the complexity of plausable structural models relating fatality rates t...

Measurement and Structural Model Class Separation in Mixture CFA: ML/EM versus MCMC

ERIC Educational Resources Information Center

Depaoli, Sarah

2012-01-01

Parameter recovery was assessed within mixture confirmatory factor analysis across multiple estimator conditions under different simulated levels of mixture class separation. Mixture class separation was defined in the measurement model (through factor loadings) and the structural model (through factor variances). Maximum likelihood (ML) via the…

New method to incorporate Type B uncertainty into least-squares procedures in radionuclide metrology.

PubMed

Han, Jubong; Lee, K B; Lee, Jong-Man; Park, Tae Soon; Oh, J S; Oh, Pil-Jei

2016-03-01

We discuss a new method to incorporate Type B uncertainty into least-squares procedures. The new method is based on an extension of the likelihood function from which a conventional least-squares function is derived. The extended likelihood function is the product of the original likelihood function with additional PDFs (Probability Density Functions) that characterize the Type B uncertainties. The PDFs are considered to describe one's incomplete knowledge on correction factors being called nuisance parameters. We use the extended likelihood function to make point and interval estimations of parameters in the basically same way as the least-squares function used in the conventional least-squares method is derived. Since the nuisance parameters are not of interest and should be prevented from appearing in the final result, we eliminate such nuisance parameters by using the profile likelihood. As an example, we present a case study for a linear regression analysis with a common component of Type B uncertainty. In this example we compare the analysis results obtained from using our procedure with those from conventional methods. Copyright © 2015. Published by Elsevier Ltd.

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

ERIC Educational Resources Information Center

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…

The Effect of Missing Data Handling Methods on Goodness of Fit Indices in Confirmatory Factor Analysis

ERIC Educational Resources Information Center

Köse, Alper

2014-01-01

The primary objective of this study was to examine the effect of missing data on goodness of fit statistics in confirmatory factor analysis (CFA). For this aim, four missing data handling methods; listwise deletion, full information maximum likelihood, regression imputation and expectation maximization (EM) imputation were examined in terms of…

Quantifying the Strength of General Factors in Psychopathology: A Comparison of CFA with Maximum Likelihood Estimation, BSEM, and ESEM/EFA Bifactor Approaches.

PubMed

Murray, Aja Louise; Booth, Tom; Eisner, Manuel; Obsuth, Ingrid; Ribeaud, Denis

2018-05-22

Whether or not importance should be placed on an all-encompassing general factor of psychopathology (or p factor) in classifying, researching, diagnosing, and treating psychiatric disorders depends (among other issues) on the extent to which comorbidity is symptom-general rather than staying largely within the confines of narrower transdiagnostic factors such as internalizing and externalizing. In this study, we compared three methods of estimating p factor strength. We compared omega hierarchical and explained common variance calculated from confirmatory factor analysis (CFA) bifactor models with maximum likelihood (ML) estimation, from exploratory structural equation modeling/exploratory factor analysis models with a bifactor rotation, and from Bayesian structural equation modeling (BSEM) bifactor models. Our simulation results suggested that BSEM with small variance priors on secondary loadings might be the preferred option. However, CFA with ML also performed well provided secondary loadings were modeled. We provide two empirical examples of applying the three methodologies using a normative sample of youth (z-proso, n = 1,286) and a university counseling sample (n = 359).

Psychometric properties of revised Thought-Action Fusion questionnaire (TAF-R) in an Iranian population.

PubMed

Pourfaraj, Majid; Mohammadi, Nourallah; Taghavi, Mohammadreza

2008-12-01

The purpose of this study is to examine the psychometric properties of Thought-Action Fusion revised scale (TAF-R; Amir, N., freshman, M., Ramsey, B., Neary, E., & Brigidi, B. (2001). Thought-action fusion in individuals with OCD symptoms. Behaviour Research and Therapy, 39, 765-776) in a sample of 565 (321 female) students of Shiraz university. The results of factor analysis with using varimax rotation yielded eight factors that explained 80% variances of total scale. These factors are labeled: moral TAF, responsibility for positive thoughts, likelihood negative events, likelihood positive events, responsibility for negative thoughts, responsibility for harm avoidance, likelihood harm avoidance and likelihood self, respectively. The reliability coefficients of total scale are calculated by two methods: internal consistency and test-retest, which were 0.81 and 0.61, respectively. Concurrent validity showed that TAF-R scores positively and significantly correlate with responsibility, guilt and obsessive-compulsive symptoms. Confirming the expectations, there were people with high obsessive-compulsive symptoms having higher TAF-R scores than those with low symptoms. Moreover, subscales-total correlations showed that the correlations between subscales were low, but subscales correlating with total score of TAF-R were moderated.

An Analysis of Factor Extraction Strategies: A Comparison of the Relative Strengths of Principal Axis, Ordinary Least Squares, and Maximum Likelihood in Research Contexts That Include Both Categorical and Continuous Variables

ERIC Educational Resources Information Center

Coughlin, Kevin B.

2013-01-01

This study is intended to provide researchers with empirically derived guidelines for conducting factor analytic studies in research contexts that include dichotomous and continuous levels of measurement. This study is based on the hypotheses that ordinary least squares (OLS) factor analysis will yield more accurate parameter estimates than…

Human Factors Process Task Analysis: Liquid Oxygen Pump Acceptance Test Procedure at the Advanced Technology Development Center

NASA Technical Reports Server (NTRS)

Diorio, Kimberly A.; Voska, Ned (Technical Monitor)

2002-01-01

This viewgraph presentation provides information on Human Factors Process Failure Modes and Effects Analysis (HF PFMEA). HF PFMEA includes the following 10 steps: Describe mission; Define System; Identify human-machine; List human actions; Identify potential errors; Identify factors that effect error; Determine likelihood of error; Determine potential effects of errors; Evaluate risk; Generate solutions (manage error). The presentation also describes how this analysis was applied to a liquid oxygen pump acceptance test.

Incorporating real-time traffic and weather data to explore road accident likelihood and severity in urban arterials.

PubMed

Theofilatos, Athanasios

2017-06-01

The effective treatment of road accidents and thus the enhancement of road safety is a major concern to societies due to the losses in human lives and the economic and social costs. The investigation of road accident likelihood and severity by utilizing real-time traffic and weather data has recently received significant attention by researchers. However, collected data mainly stem from freeways and expressways. Consequently, the aim of the present paper is to add to the current knowledge by investigating accident likelihood and severity by exploiting real-time traffic and weather data collected from urban arterials in Athens, Greece. Random Forests (RF) are firstly applied for preliminary analysis purposes. More specifically, it is aimed to rank candidate variables according to their relevant importance and provide a first insight on the potential significant variables. Then, Bayesian logistic regression as well finite mixture and mixed effects logit models are applied to further explore factors associated with accident likelihood and severity respectively. Regarding accident likelihood, the Bayesian logistic regression showed that variations in traffic significantly influence accident occurrence. On the other hand, accident severity analysis revealed a generally mixed influence of traffic variations on accident severity, although international literature states that traffic variations increase severity. Lastly, weather parameters did not find to have a direct influence on accident likelihood or severity. The study added to the current knowledge by incorporating real-time traffic and weather data from urban arterials to investigate accident occurrence and accident severity mechanisms. The identification of risk factors can lead to the development of effective traffic management strategies to reduce accident occurrence and severity of injuries in urban arterials. Copyright © 2017 Elsevier Ltd and National Safety Council. All rights reserved.

Factors associated with the likelihood of Giardia spp. and Cryptosporidium spp. in soil from dairy farms.

PubMed

Barwick, R S; Mohammed, H O; White, M E; Bryant, R B

2003-03-01

A study was conducted to identify factors associated with the likelihood of detecting Giardia spp. and Cryptosporidium spp. in the soil of dairy farms in a watershed area. A total of 37 farms were visited, and 782 soil samples were collected from targeted areas on these farms. The samples were analyzed for the presence of Cryptosporidium spp. oocysts, Giardia spp. cysts, percent moisture content, and pH. Logistic regression analysis was used to identify risk factors associated with the likelihood of the presence of these organisms. The use of the land at the sampling site was associated with the likelihood of environmental contamination with Cryptosporidium spp. Barn cleaner equipment area and agricultural fields were associated with increased likelihood of environmental contamination with Cryptosporidium spp. The risk of environmental contamination decreased with the pH of the soil and with the score of the potential likelihood of Cryptosporidium spp. The size of the sampling site, as determined by the sampling design, in square feet, was associated nonlinearly with the risk of detecting Cryptosporidium spp. The likelihood of the Giardia cyst in the soil increased with the prevalence of Giardia spp. in animals (i.e., 18 to 39%). As the size of the farm increased, there was decreased risk of Giardia spp. in the soil, and sampling sites which were covered with brush or bare soil showed a decrease in likelihood of detecting Giardia spp. when compared to land which had managed grass. The number of cattle on the farm less than 6 mo of age was negatively associated with the risk of detecting Giardia spp. in the soil, and the percent moisture content was positively associated with the risk of detecting Giardia spp. Our study showed that these two protozoan exist in dairy farm soil at different rates, and this risk could be modified by manipulating the pH of the soil.

Collinear Latent Variables in Multilevel Confirmatory Factor Analysis

PubMed Central

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 influence of the size of the intraclass correlation coefficient (ICC) and estimation method; maximum likelihood estimation with robust chi-squares and standard errors and Bayesian estimation, on the convergence rate are investigated. The other variables of interest were rate of inadmissible solutions and the relative parameter and standard error bias on the between level. The results showed that inadmissible solutions were obtained when there was between level collinearity and the estimation method was maximum likelihood. In the within level multicollinearity condition, all of the solutions were admissible but the bias values were higher compared with the between level collinearity condition. Bayesian estimation appeared to be robust in obtaining admissible parameters but the relative bias was higher than for maximum likelihood estimation. Finally, as expected, high ICC produced less biased results compared to medium ICC conditions. PMID:29795827

Survival analysis of clinical mastitis data using a nested frailty Cox model fit as a mixed-effects Poisson model.

PubMed

Elghafghuf, Adel; Dufour, Simon; Reyher, Kristen; Dohoo, Ian; Stryhn, Henrik

2014-12-01

Mastitis is a complex disease affecting dairy cows and is considered to be the most costly disease of dairy herds. The hazard of mastitis is a function of many factors, both managerial and environmental, making its control a difficult issue to milk producers. Observational studies of clinical mastitis (CM) often generate datasets with a number of characteristics which influence the analysis of those data: the outcome of interest may be the time to occurrence of a case of mastitis, predictors may change over time (time-dependent predictors), the effects of factors may change over time (time-dependent effects), there are usually multiple hierarchical levels, and datasets may be very large. Analysis of such data often requires expansion of the data into the counting-process format - leading to larger datasets - thus complicating the analysis and requiring excessive computing time. In this study, a nested frailty Cox model with time-dependent predictors and effects was applied to Canadian Bovine Mastitis Research Network data in which 10,831 lactations of 8035 cows from 69 herds were followed through lactation until the first occurrence of CM. The model was fit to the data as a Poisson model with nested normally distributed random effects at the cow and herd levels. Risk factors associated with the hazard of CM during the lactation were identified, such as parity, calving season, herd somatic cell score, pasture access, fore-stripping, and proportion of treated cases of CM in a herd. The analysis showed that most of the predictors had a strong effect early in lactation and also demonstrated substantial variation in the baseline hazard among cows and between herds. A small simulation study for a setting similar to the real data was conducted to evaluate the Poisson maximum likelihood estimation approach with both Gaussian quadrature method and Laplace approximation. Further, the performance of the two methods was compared with the performance of a widely used estimation approach for frailty Cox models based on the penalized partial likelihood. The simulation study showed good performance for the Poisson maximum likelihood approach with Gaussian quadrature and biased variance component estimates for both the Poisson maximum likelihood with Laplace approximation and penalized partial likelihood approaches. Copyright © 2014. Published by Elsevier B.V.

Estimation and Testing of Partial Covariances, Correlations, and Regression Weights Using Maximum Likelihood Factor Analysis.

ERIC Educational Resources Information Center

And Others; Werts, Charles E.

1979-01-01

It is shown how partial covariance, part and partial correlation, and regression weights can be estimated and tested for significance by means of a factor analytic model. Comparable partial covariance, correlations, and regression weights have identical significance tests. (Author)

Perception of risk from automobile safety defects.

PubMed

Slovic, P; MacGregor, D; Kraus, N N

1987-10-01

Descriptions of safety engineering defects of the kind that compel automobile manufacturers to initiate a recall campaign were evaluated by individuals on a set of risk characteristic scales that included overall vehicle riskiness, manufacturer's ability to anticipate the defect, importance for vehicle operation, severity of consequences and likelihood of compliance with a recall notice. A factor analysis of the risk characteristics indicated that judgments could be summarized in terms of two composite scales, one representing the uncontrollability of the damage the safety defect might cause and the other representing the foreseeability of the defect by the manufacturer. Motor vehicle defects were found to be highly diverse in terms of the perceived qualities of their risks. Location of individual defects within the factor space was closely associated with perceived riskiness, perceived likelihood of purchasing another car from the same manufacturer, perceived likelihood of compliance with a recall notice, and actual compliance rates.

Factors Associated With the Likelihood of Hospitalization Following Emergency Department Visits for Behavioral Health Conditions.

PubMed

Hamilton, Jane E; Desai, Pratikkumar V; Hoot, Nathan R; Gearing, Robin E; Jeong, Shin; Meyer, Thomas D; Soares, Jair C; Begley, Charles E

2016-11-01

Behavioral health-related emergency department (ED) visits have been linked with ED overcrowding, an increased demand on limited resources, and a longer length of stay (LOS) due in part to patients being admitted to the hospital but waiting for an inpatient bed. This study examines factors associated with the likelihood of hospital admission for ED patients with behavioral health conditions at 16 hospital-based EDs in a large urban area in the southern United States. Using Andersen's Behavioral Model of Health Service Use for guidance, the study examined the relationship between predisposing (characteristics of the individual, i.e., age, sex, race/ethnicity), enabling (system or structural factors affecting healthcare access), and need (clinical) factors and the likelihood of hospitalization following ED visits for behavioral health conditions (n = 28,716 ED visits). In the adjusted analysis, a logistic fixed-effects model with blockwise entry was used to estimate the relative importance of predisposing, enabling, and need variables added separately as blocks while controlling for variation in unobserved hospital-specific practices across hospitals and time in years. Significant predisposing factors associated with an increased likelihood of hospitalization following an ED visit included increasing age, while African American race was associated with a lower likelihood of hospitalization. Among enabling factors, arrival by emergency transport and a longer ED LOS were associated with a greater likelihood of hospitalization while being uninsured and the availability of community-based behavioral health services within 5 miles of the ED were associated with lower odds. Among need factors, having a discharge diagnosis of schizophrenia/psychotic spectrum disorder, an affective disorder, a personality disorder, dementia, or an impulse control disorder as well as secondary diagnoses of suicidal ideation and/or suicidal behavior increased the likelihood of hospitalization following an ED visit. The block of enabling factors was the strongest predictor of hospitalization following an ED visit compared to predisposing and need factors. Our findings also provide evidence of disparities in hospitalization of the uninsured and racial and ethnic minority patients with ED visits for behavioral health conditions. Thus, improved access to community-based behavioral health services and an increased capacity for inpatient psychiatric hospitals for treating indigent patients may be needed to improve the efficiency of ED services in our region for patients with behavioral health conditions. Among need factors, a discharge diagnosis of schizophrenia/psychotic spectrum disorder, an affective disorder, a personality disorder, an impulse control disorder, or dementia as well as secondary diagnoses of suicidal ideation and/or suicidal behavior increased the likelihood of hospitalization following an ED visit, also suggesting an opportunity for improving the efficiency of ED care through the provision of psychiatric services to stabilize and treat patients with serious mental illness. © 2016 by the Society for Academic Emergency Medicine.

Factors Associated with Living in Developmental Centers in California

ERIC Educational Resources Information Center

Harrington, Charlene; Kang, Taewoon; Chang, Jamie

2009-01-01

This study examined need, predisposing, market, and regional factors that predicted the likelihood of individuals with developmental disabilities living in state developmental centers (DCs) compared with living at home, in community care, or in intermediate care (ICFs) and other facilities. Secondary data analysis using logistic regression models…

MrBayes tgMC3++: A High Performance and Resource-Efficient GPU-Oriented Phylogenetic Analysis Method.

PubMed

Ling, Cheng; Hamada, Tsuyoshi; Gao, Jingyang; Zhao, Guoguang; Sun, Donghong; Shi, Weifeng

2016-01-01

MrBayes is a widespread phylogenetic inference tool harnessing empirical evolutionary models and Bayesian statistics. However, the computational cost on the likelihood estimation is very expensive, resulting in undesirably long execution time. Although a number of multi-threaded optimizations have been proposed to speed up MrBayes, there are bottlenecks that severely limit the GPU thread-level parallelism of likelihood estimations. This study proposes a high performance and resource-efficient method for GPU-oriented parallelization of likelihood estimations. Instead of having to rely on empirical programming, the proposed novel decomposition storage model implements high performance data transfers implicitly. In terms of performance improvement, a speedup factor of up to 178 can be achieved on the analysis of simulated datasets by four Tesla K40 cards. In comparison to the other publicly available GPU-oriented MrBayes, the tgMC 3 ++ method (proposed herein) outperforms the tgMC 3 (v1.0), nMC 3 (v2.1.1) and oMC 3 (v1.00) methods by speedup factors of up to 1.6, 1.9 and 2.9, respectively. Moreover, tgMC 3 ++ supports more evolutionary models and gamma categories, which previous GPU-oriented methods fail to take into analysis.

Human factors process failure modes and effects analysis (HF PFMEA) software tool

NASA Technical Reports Server (NTRS)

Chandler, Faith T. (Inventor); Relvini, Kristine M. (Inventor); Shedd, Nathaneal P. (Inventor); Valentino, William D. (Inventor); Philippart, Monica F. (Inventor); Bessette, Colette I. (Inventor)

2011-01-01

Methods, computer-readable media, and systems for automatically performing Human Factors Process Failure Modes and Effects Analysis for a process are provided. At least one task involved in a process is identified, where the task includes at least one human activity. The human activity is described using at least one verb. A human error potentially resulting from the human activity is automatically identified, the human error is related to the verb used in describing the task. A likelihood of occurrence, detection, and correction of the human error is identified. The severity of the effect of the human error is identified. The likelihood of occurrence, and the severity of the risk of potential harm is identified. The risk of potential harm is compared with a risk threshold to identify the appropriateness of corrective measures.

Socio-Economic Factors Affecting Adoption of Modern Information and Communication Technology by Farmers in India: Analysis Using Multivariate Probit Model

ERIC Educational Resources Information Center

Mittal, Surabhi; Mehar, Mamta

2016-01-01

Purpose: The paper analyzes factors that affect the likelihood of adoption of different agriculture-related information sources by farmers. Design/Methodology/Approach: The paper links the theoretical understanding of the existing multiple sources of information that farmers use, with the empirical model to analyze the factors that affect the…

Adjusted Analyses in Studies Addressing Therapy and Harm: Users' Guides to the Medical Literature.

PubMed

Agoritsas, Thomas; Merglen, Arnaud; Shah, Nilay D; O'Donnell, Martin; Guyatt, Gordon H

2017-02-21

Observational studies almost always have bias because prognostic factors are unequally distributed between patients exposed or not exposed to an intervention. The standard approach to dealing with this problem is adjusted or stratified analysis. Its principle is to use measurement of risk factors to create prognostically homogeneous groups and to combine effect estimates across groups.The purpose of this Users' Guide is to introduce readers to fundamental concepts underlying adjustment as a way of dealing with prognostic imbalance and to the basic principles and relative trustworthiness of various adjustment strategies.One alternative to the standard approach is propensity analysis, in which groups are matched according to the likelihood of membership in exposed or unexposed groups. Propensity methods can deal with multiple prognostic factors, even if there are relatively few patients having outcome events. However, propensity methods do not address other limitations of traditional adjustment: investigators may not have measured all relevant prognostic factors (or not accurately), and unknown factors may bias the results.A second approach, instrumental variable analysis, relies on identifying a variable associated with the likelihood of receiving the intervention but not associated with any prognostic factor or with the outcome (other than through the intervention); this could mimic randomization. However, as with assumptions of other adjustment approaches, it is never certain if an instrumental variable analysis eliminates bias.Although all these approaches can reduce the risk of bias in observational studies, none replace the balance of both known and unknown prognostic factors offered by randomization.

Bayesian structural equation modeling in sport and exercise psychology.

PubMed

Stenling, Andreas; Ivarsson, Andreas; Johnson, Urban; Lindwall, Magnus

2015-08-01

Bayesian statistics is on the rise in mainstream psychology, but applications in sport and exercise psychology research are scarce. In this article, the foundations of Bayesian analysis are introduced, and we will illustrate how to apply Bayesian structural equation modeling in a sport and exercise psychology setting. More specifically, we contrasted a confirmatory factor analysis on the Sport Motivation Scale II estimated with the most commonly used estimator, maximum likelihood, and a Bayesian approach with weakly informative priors for cross-loadings and correlated residuals. The results indicated that the model with Bayesian estimation and weakly informative priors provided a good fit to the data, whereas the model estimated with a maximum likelihood estimator did not produce a well-fitting model. The reasons for this discrepancy between maximum likelihood and Bayesian estimation are discussed as well as potential advantages and caveats with the Bayesian approach.

Seniors, health information, and the Internet: motivation, ability, and Internet knowledge.

PubMed

Sheng, Xiaojing; Simpson, Penny M

2013-10-01

Providing health information to older adults is crucial to empowering them to better control their health, and the information is readily available on the Internet. Yet, little is known about the factors that are important in affecting seniors' Internet search for health information behavior. This work addresses this research deficit by examining the role of health information orientation (HIO), eHealth literacy, and Internet knowledge (IK) in affecting the likelihood of using the Internet as a source for health information. The analysis reveals that each variable in the study is significant in affecting Internet search likelihood. Results from the analysis also demonstrate the partial mediating role of eHealth literacy and the interaction between eHealth literacy and HIO. The findings suggest that improving seniors' IK and eHealth literacy would increase their likelihood of searching for and finding health information on the Internet that might encourage better health behaviors.

A Class of Factor Analysis Estimation Procedures with Common Asymptotic Sampling Properties

ERIC Educational Resources Information Center

Swain, A. J.

1975-01-01

Considers a class of estimation procedures for the factor model. The procedures are shown to yield estimates possessing the same asymptotic sampling properties as those from estimation by maximum likelihood or generalized last squares, both special members of the class. General expressions for the derivatives needed for Newton-Raphson…

Predicting Likelihood of Surgery Prior to First Visit in Patients with Back and Lower Extremity Symptoms: A simple mathematical model based on over 8000 patients.

PubMed

Boden, Lauren M; Boden, Stephanie A; Premkumar, Ajay; Gottschalk, Michael B; Boden, Scott D

2018-02-09

Retrospective analysis of prospectively collected data. To create a data-driven triage system stratifying patients by likelihood of undergoing spinal surgery within one year of presentation. Low back pain (LBP) and radicular lower extremity (LE) symptoms are common musculoskeletal problems. There is currently no standard data-derived triage process based on information that can be obtained prior to the initial physician-patient encounter to direct patients to the optimal physician type. We analyzed patient-reported data from 8006 patients with a chief complaint of LBP and/or LE radicular symptoms who presented to surgeons at a large multidisciplinary spine center between September 1, 2005 and June 30, 2016. Univariate and multivariate analysis identified independent risk factors for undergoing spinal surgery within one year of initial visit. A model incorporating these risk factors was created using a random sample of 80% of the total patients in our cohort, and validated on the remaining 20%. The baseline one-year surgery rate within our cohort was 39% for all patients and 42% for patients with LE symptoms. Those identified as high likelihood by the center's existing triage process had a surgery rate of 45%. The new triage scoring system proposed in this study was able to identify a high likelihood group in which 58% underwent surgery, which is a 46% higher surgery rate than in non-triaged patients and a 29% improvement from our institution's existing triage system. The data-driven triage model and scoring system derived and validated in this study (Spine Surgery Likelihood model [SSL-11]), significantly improved existing processes in predicting the likelihood of undergoing spinal surgery within one year of initial presentation. This triage system will allow centers to more selectively screen for surgical candidates and more effectively direct patients to surgeons or non-operative spine specialists. 4.

Silence That Can Be Dangerous: A Vignette Study to Assess Healthcare Professionals’ Likelihood of Speaking up about Safety Concerns

PubMed Central

Schwappach, David L. B.; Gehring, Katrin

2014-01-01

Purpose To investigate the likelihood of speaking up about patient safety in oncology and to clarify the effect of clinical and situational context factors on the likelihood of voicing concerns. Patients and Methods 1013 nurses and doctors in oncology rated four clinical vignettes describing coworkers’ errors and rule violations in a self-administered factorial survey (65% response rate). Multiple regression analysis was used to model the likelihood of speaking up as outcome of vignette attributes, responder’s evaluations of the situation and personal characteristics. Results Respondents reported a high likelihood of speaking up about patient safety but the variation between and within types of errors and rule violations was substantial. Staff without managerial function provided significantly higher levels of decision difficulty and discomfort to speak up. Based on the information presented in the vignettes, 74%−96% would speak up towards a supervisor failing to check a prescription, 45%−81% would point a coworker to a missed hand disinfection, 82%−94% would speak up towards nurses who violate a safety rule in medication preparation, and 59%−92% would question a doctor violating a safety rule in lumbar puncture. Several vignette attributes predicted the likelihood of speaking up. Perceived potential harm, anticipated discomfort, and decision difficulty were significant predictors of the likelihood of speaking up. Conclusions Clinicians’ willingness to speak up about patient safety is considerably affected by contextual factors. Physicians and nurses without managerial function report substantial discomfort with speaking up. Oncology departments should provide staff with clear guidance and trainings on when and how to voice safety concerns. PMID:25116338

Drivers of wetland conversion: a global meta-analysis.

PubMed

van Asselen, Sanneke; Verburg, Peter H; Vermaat, Jan E; Janse, Jan H

2013-01-01

Meta-analysis of case studies has become an important tool for synthesizing case study findings in land change. Meta-analyses of deforestation, urbanization, desertification and change in shifting cultivation systems have been published. This present study adds to this literature, with an analysis of the proximate causes and underlying forces of wetland conversion at a global scale using two complementary approaches of systematic review. Firstly, a meta-analysis of 105 case-study papers describing wetland conversion was performed, showing that different combinations of multiple-factor proximate causes, and underlying forces, drive wetland conversion. Agricultural development has been the main proximate cause of wetland conversion, and economic growth and population density are the most frequently identified underlying forces. Secondly, to add a more quantitative component to the study, a logistic meta-regression analysis was performed to estimate the likelihood of wetland conversion worldwide, using globally-consistent biophysical and socioeconomic location factor maps. Significant factors explaining wetland conversion, in order of importance, are market influence, total wetland area (lower conversion probability), mean annual temperature and cropland or built-up area. The regression analyses results support the outcomes of the meta-analysis of the processes of conversion mentioned in the individual case studies. In other meta-analyses of land change, similar factors (e.g., agricultural development, population growth, market/economic factors) are also identified as important causes of various types of land change (e.g., deforestation, desertification). Meta-analysis helps to identify commonalities across the various local case studies and identify which variables may lead to individual cases to behave differently. The meta-regression provides maps indicating the likelihood of wetland conversion worldwide based on the location factors that have determined historic conversions.

Drivers of Wetland Conversion: a Global Meta-Analysis

PubMed Central

van Asselen, Sanneke; Verburg, Peter H.; Vermaat, Jan E.; Janse, Jan H.

2013-01-01

Meta-analysis of case studies has become an important tool for synthesizing case study findings in land change. Meta-analyses of deforestation, urbanization, desertification and change in shifting cultivation systems have been published. This present study adds to this literature, with an analysis of the proximate causes and underlying forces of wetland conversion at a global scale using two complementary approaches of systematic review. Firstly, a meta-analysis of 105 case-study papers describing wetland conversion was performed, showing that different combinations of multiple-factor proximate causes, and underlying forces, drive wetland conversion. Agricultural development has been the main proximate cause of wetland conversion, and economic growth and population density are the most frequently identified underlying forces. Secondly, to add a more quantitative component to the study, a logistic meta-regression analysis was performed to estimate the likelihood of wetland conversion worldwide, using globally-consistent biophysical and socioeconomic location factor maps. Significant factors explaining wetland conversion, in order of importance, are market influence, total wetland area (lower conversion probability), mean annual temperature and cropland or built-up area. The regression analyses results support the outcomes of the meta-analysis of the processes of conversion mentioned in the individual case studies. In other meta-analyses of land change, similar factors (e.g., agricultural development, population growth, market/economic factors) are also identified as important causes of various types of land change (e.g., deforestation, desertification). Meta-analysis helps to identify commonalities across the various local case studies and identify which variables may lead to individual cases to behave differently. The meta-regression provides maps indicating the likelihood of wetland conversion worldwide based on the location factors that have determined historic conversions. PMID:24282580

Exploratory factor analysis of the 12-item Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Scale in people newly diagnosed with advanced cancer.

PubMed

Bai, Mei; Dixon, Jane K

2014-01-01

The purpose of this study was to reexamine the factor pattern of the 12-item Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Scale (FACIT-Sp-12) using exploratory factor analysis in people newly diagnosed with advanced cancer. Principal components analysis (PCA) and 3 common factor analysis methods were used to explore the factor pattern of the FACIT-Sp-12. Factorial validity was assessed in association with quality of life (QOL). Principal factor analysis (PFA), iterative PFA, and maximum likelihood suggested retrieving 3 factors: Peace, Meaning, and Faith. Both Peace and Meaning positively related to QOL, whereas only Peace uniquely contributed to QOL. This study supported the 3-factor model of the FACIT-Sp-12. Suggestions for revision of items and further validation of the identified factor pattern were provided.

Risk factors for classical hysterotomy by gestational age.

PubMed

Osmundson, Sarah S; Garabedian, Matthew J; Lyell, Deirdre J

2013-10-01

To examine the likelihood of classical hysterotomy across preterm gestational ages and to identify factors that increase its occurrence. This is a secondary analysis of a prospective observational cohort collected by the Maternal-Fetal Medicine Network of all women with singleton gestations who underwent a cesarean delivery with a known hysterotomy. Comparisons were made based on gestational age. Factors thought to influence hysterotomy type were studied, including maternal age, body mass index, parity, birth weight, small for gestational age (SGA) status, fetal presentation, labor preceding delivery, and emergent delivery. Approximately 36,000 women were eligible for analysis, of whom 34,454 (95.7%) underwent low transverse hysterotomy and 1,562 (4.3%) underwent classical hysterotomy. The median gestational age of women undergoing a classical hysterotomy was 32 weeks and the incidence peaked between 24 0/7 weeks and 25 6/7 weeks (53.2%), declining with each additional week of gestation thereafter (P for trend <.001). In multivariable regression, the likelihood of classical hysterotomy was increased with SGA (n=258; odds ratio [OR] 2.71; confidence interval [CI] 1.78-4.13), birth weight 1,000 g or less (n=467; OR 1.51; CI 1.03-2.24), and noncephalic presentation (n=783; OR 2.03; CI 1.52-2.72). The likelihood of classical hysterotomy was decreased between 23 0/7 and 27 6/7 weeks of gestation and after 32 weeks of gestation when labor preceded delivery, and increased between 28 0/7 and 31 6/7 weeks of gestation and after 32 weeks of gestation by multiparity and previous cesarean delivery. Emergent delivery did not predict classical hysterotomy. Fifty percent of women at 23-26 weeks of gestation who undergo cesarean delivery have a classical hysterotomy, and the risk declines steadily thereafter. This likelihood is increased by fetal factors, especially SGA and noncephalic presentation. : II.

The Complex Relationship between Dependency and Domestic Violence: Converging Psychological Factors and Social Forces

ERIC Educational Resources Information Center

Bornstein, Robert F.

2006-01-01

Research indicates that economic dependency in women and emotional dependency in men independently contribute to domestic-partner abuse risk and that high levels of emotional dependency in an abused partner may reduce the likelihood that the victimized person will terminate the relationship. An analysis of psychological factors and social forces…

Quantifying the Establishment Likelihood of Invasive Alien Species Introductions Through Ports with Application to Honeybees in Australia.

PubMed

Heersink, Daniel K; Caley, Peter; Paini, Dean R; Barry, Simon C

2016-05-01

The cost of an uncontrolled incursion of invasive alien species (IAS) arising from undetected entry through ports can be substantial, and knowledge of port-specific risks is needed to help allocate limited surveillance resources. Quantifying the establishment likelihood of such an incursion requires quantifying the ability of a species to enter, establish, and spread. Estimation of the approach rate of IAS into ports provides a measure of likelihood of entry. Data on the approach rate of IAS are typically sparse, and the combinations of risk factors relating to country of origin and port of arrival diverse. This presents challenges to making formal statistical inference on establishment likelihood. Here we demonstrate how these challenges can be overcome with judicious use of mixed-effects models when estimating the incursion likelihood into Australia of the European (Apis mellifera) and Asian (A. cerana) honeybees, along with the invasive parasites of biosecurity concern they host (e.g., Varroa destructor). Our results demonstrate how skewed the establishment likelihood is, with one-tenth of the ports accounting for 80% or more of the likelihood for both species. These results have been utilized by biosecurity agencies in the allocation of resources to the surveillance of maritime ports. © 2015 Society for Risk Analysis.

Approximate likelihood approaches for detecting the influence of primordial gravitational waves in cosmic microwave background polarization

NASA Astrophysics Data System (ADS)

Pan, Zhen; Anderes, Ethan; Knox, Lloyd

2018-05-01

One of the major targets for next-generation cosmic microwave background (CMB) experiments is the detection of the primordial B-mode signal. Planning is under way for Stage-IV experiments that are projected to have instrumental noise small enough to make lensing and foregrounds the dominant source of uncertainty for estimating the tensor-to-scalar ratio r from polarization maps. This makes delensing a crucial part of future CMB polarization science. In this paper we present a likelihood method for estimating the tensor-to-scalar ratio r from CMB polarization observations, which combines the benefits of a full-scale likelihood approach with the tractability of the quadratic delensing technique. This method is a pixel space, all order likelihood analysis of the quadratic delensed B modes, and it essentially builds upon the quadratic delenser by taking into account all order lensing and pixel space anomalies. Its tractability relies on a crucial factorization of the pixel space covariance matrix of the polarization observations which allows one to compute the full Gaussian approximate likelihood profile, as a function of r , at the same computational cost of a single likelihood evaluation.

Hospital mergers and market overlap.

PubMed Central

Brooks, G R; Jones, V G

1997-01-01

OBJECTIVE: To address two questions: What are the characteristics of hospitals that affect the likelihood of their being involved in a merger? What characteristics of particular pairs of hospitals affect the likelihood of the pair engaging in a merger? DATA SOURCES/STUDY SETTING: Hospitals in the 12 county region surrounding the San Francisco Bay during the period 1983 to 1992 were the focus of the study. Data were drawn from secondary sources, including the Lexis/Nexis database, the American Hospital Association, and the Office of Statewide Health Planning and Development of the State of California. STUDY DESIGN: Seventeen hospital mergers during the study period were identified. A random sample of pairs of hospitals that did not merge was drawn to establish a statistically efficient control set. Models constructed from hypotheses regarding hospital and market characteristics believed to be related to merger likelihood were tested using logistic regression analysis. DATA COLLECTION: See Data Sources/Study Setting. PRINCIPAL FINDINGS: The analysis shows that the likelihood of a merger between a particular pair of hospitals is positively related to the degree of market overlap that exists between them. Furthermore, market overlap and performance difference interact in their effect on merger likelihood. In an analysis of individual hospitals, conditions of rivalry, hospital market share, and hospital size were not found to influence the likelihood that a hospital will engage in a merger. CONCLUSIONS: Mergers between hospitals are not driven directly by considerations of market power or efficiency as much as by the existence of specific merger opportunities in the hospitals' local markets. Market overlap is a condition that enables a merger to occur, but other factors, such as the relative performance levels of the hospitals in question and their ownership and teaching status, also play a role in influencing the likelihood that a merger will in fact take place. PMID:9018212

Factors related to choosing an academic career track among spine fellowship applicants.

PubMed

Park, Daniel K; Rhee, John M; Wu, Baohua; Easley, Kirk

2013-03-01

Retrospective review. To identify factors associated with the likelihood of spine surgery fellowship applicants choosing an academic job upon fellowship completion. Training academic spine surgeons is an important goal of many spine fellowships. However, there are no established criteria associated with academic job choice to guide selection committees. Two hundred three consecutive applications of candidates who were granted an interview to a single spine surgical fellowship from 2005 to 2010 were analyzed. Factors investigated included the following: membership in honor societies; number of publications, presentations, and book chapters; age; completion of an additional degree; completion of a research fellowship; teaching experience; marital status; graduation from a top-20 school; attendance in a residency with a spine fellowship; and comments made in personal statements and letters of recommendation. The job taken upon graduation from fellowship was determined. The χ2 test or Fisher exact test was used to estimate the strength of the association between the covariates and response. Significant variables were selected for further multivariate analysis. The following were significantly associated in a univariable analysis with academia: 5 or more national presentations; completion of a research fellowship; attendance in a top-20 medical school; stated desire in the personal statement to become an academic surgeon; and letters of reference stating likelihood of pursuing academics on hiring the applicant. When significant variables were selected for multivariable analysis, completion of a research fellowship, graduation from a top-20 medical school, and stated desire in the personal statement to become an academic surgeon were most strongly associated with choice of academia. Although job choice is multifactorial, the present study demonstrates that there are objective factors listed on spine fellowship applications associated with a significantly higher likelihood of academic job choice. Analyzing these factors may help selection committees evaluate spine fellowship applicants consistent with the academic missions of their programs.

Exploring the Factor Structure of Neurocognitive Measures in Older Individuals

PubMed Central

Santos, Nadine Correia; Costa, Patrício Soares; Amorim, Liliana; Moreira, Pedro Silva; Cunha, Pedro; Cotter, Jorge; Sousa, Nuno

2015-01-01

Here we focus on factor analysis from a best practices point of view, by investigating the factor structure of neuropsychological tests and using the results obtained to illustrate on choosing a reasonable solution. The sample (n=1051 individuals) was randomly divided into two groups: one for exploratory factor analysis (EFA) and principal component analysis (PCA), to investigate the number of factors underlying the neurocognitive variables; the second to test the “best fit” model via confirmatory factor analysis (CFA). For the exploratory step, three extraction (maximum likelihood, principal axis factoring and principal components) and two rotation (orthogonal and oblique) methods were used. The analysis methodology allowed exploring how different cognitive/psychological tests correlated/discriminated between dimensions, indicating that to capture latent structures in similar sample sizes and measures, with approximately normal data distribution, reflective models with oblimin rotation might prove the most adequate. PMID:25880732

Analysis of hourly crash likelihood using unbalanced panel data mixed logit model and real-time driving environmental big data.

PubMed

Chen, Feng; Chen, Suren; Ma, Xiaoxiang

2018-06-01

Driving environment, including road surface conditions and traffic states, often changes over time and influences crash probability considerably. It becomes stretched for traditional crash frequency models developed in large temporal scales to capture the time-varying characteristics of these factors, which may cause substantial loss of critical driving environmental information on crash prediction. Crash prediction models with refined temporal data (hourly records) are developed to characterize the time-varying nature of these contributing factors. Unbalanced panel data mixed logit models are developed to analyze hourly crash likelihood of highway segments. The refined temporal driving environmental data, including road surface and traffic condition, obtained from the Road Weather Information System (RWIS), are incorporated into the models. Model estimation results indicate that the traffic speed, traffic volume, curvature and chemically wet road surface indicator are better modeled as random parameters. The estimation results of the mixed logit models based on unbalanced panel data show that there are a number of factors related to crash likelihood on I-25. Specifically, weekend indicator, November indicator, low speed limit and long remaining service life of rutting indicator are found to increase crash likelihood, while 5-am indicator and number of merging ramps per lane per mile are found to decrease crash likelihood. The study underscores and confirms the unique and significant impacts on crash imposed by the real-time weather, road surface, and traffic conditions. With the unbalanced panel data structure, the rich information from real-time driving environmental big data can be well incorporated. Copyright © 2018 National Safety Council and Elsevier Ltd. All rights reserved.

A Confirmatory Factor Analysis of the California Verbal Learning Test-Second Edition (CVLT-II) in the Standardization Sample

ERIC Educational Resources Information Center

Donders, Jacobus

2008-01-01

The purpose of this study is to determine the latent structure of the California Verbal Learning Test-Second Edition (CVLT-II; Delis, Kramer, Kaplan, & Ober, 2000) at three different age levels, using the standardization sample. Maximum likelihood confirmatory factor analyses are performed to test four competing hypothetical models for fit and…

An Analysis of Retention Factors in Undergraduate Degree Programs in Science, Technology, Engineering, and Mathematics

ERIC Educational Resources Information Center

Johnson, Michael H.

2012-01-01

This mixed-methodological study explored the factors that predict a student's likelihood to complete an undergraduate program in a STEM discipline at one campus reliant upon that mission. Offered in response to a national imperative for the U.S. to compete globally, researchers contend educators must better prepare a STEM foundation and inspire…

State-Space Modeling of Dynamic Psychological Processes via the Kalman Smoother Algorithm: Rationale, Finite Sample Properties, and Applications

ERIC Educational Resources Information Center

Song, Hairong; Ferrer, Emilio

2009-01-01

This article presents a state-space modeling (SSM) technique for fitting process factor analysis models directly to raw data. The Kalman smoother via the expectation-maximization algorithm to obtain maximum likelihood parameter estimates is used. To examine the finite sample properties of the estimates in SSM when common factors are involved, a…

Early pregnancy angiogenic markers and spontaneous abortion: an Odense Child Cohort study.

PubMed

Andersen, Louise B; Dechend, Ralf; Karumanchi, S Ananth; Nielsen, Jan; Joergensen, Jan S; Jensen, Tina K; Christesen, Henrik T

2016-11-01

Spontaneous abortion is the most commonly observed adverse pregnancy outcome. The angiogenic factors soluble Fms-like kinase 1 and placental growth factor are critical for normal pregnancy and may be associated to spontaneous abortion. We investigated the association between maternal serum concentrations of soluble Fms-like kinase 1 and placental growth factor, and subsequent spontaneous abortion. In the prospective observational Odense Child Cohort, 1676 pregnant women donated serum in early pregnancy, gestational week <22 (median 83 days of gestation, interquartile range 71-103). Concentrations of soluble Fms-like kinase 1 and placental growth factor were determined with novel automated assays. Spontaneous abortion was defined as complete or incomplete spontaneous abortion, missed abortion, or blighted ovum <22+0 gestational weeks, and the prevalence was 3.52% (59 cases). The time-dependent effect of maternal serum concentrations of soluble Fms-like kinase 1 and placental growth factor on subsequent late first-trimester or second-trimester spontaneous abortion (n = 59) was evaluated using a Cox proportional hazards regression model, adjusting for body mass index, parity, season of blood sampling, and age. Furthermore, receiver operating characteristics were employed to identify predictive values and optimal cut-off values. In the adjusted Cox regression analysis, increasing continuous concentrations of both soluble Fms-like kinase 1 and placental growth factor were significantly associated with a decreased hazard ratio for spontaneous abortion: soluble Fms-like kinase 1, 0.996 (95% confidence interval, 0.995-0.997), and placental growth factor, 0.89 (95% confidence interval, 0.86-0.93). When analyzed by receiver operating characteristic cut-offs, women with soluble Fms-like kinase 1 <742 pg/mL had an odds ratio for spontaneous abortion of 12.1 (95% confidence interval, 6.64-22.2), positive predictive value of 11.70%, negative predictive value of 98.90%, positive likelihood ratio of 3.64 (3.07-4.32), and negative likelihood ratio of 0.30 (0.19-0.48). For placental growth factor <19.7 pg/mL, odds ratio was 13.2 (7.09-24.4), positive predictive value was 11.80%, negative predictive value was 99.0%, positive likelihood ratio was 3.68 (3.12-4.34), and negative likelihood ratio was 0.28 (0.17-0.45). In the sensitivity analysis of 54 spontaneous abortions matched 1:4 to controls on gestational age at blood sampling, the highest area under the curve was seen for soluble Fms-like kinase 1 in prediction of first-trimester spontaneous abortion, 0.898 (0.834-0.962), and at the optimum cut-off of 725 pg/mL, negative predictive value was 51.4%, positive predictive value was 94.6%, positive likelihood ratio was 4.04 (2.57-6.35), and negative likelihood ratio was 0.22 (0.09-0.54). A strong, novel prospective association was identified between lower concentrations of soluble Fms-like kinase 1 and placental growth factor measured in early pregnancy and spontaneous abortion. A soluble Fms-like kinase 1 cut-off <742 pg/mL in maternal serum was optimal to stratify women at high vs low risk of spontaneous abortion. The cause and effect of angiogenic factor alterations in spontaneous abortions remain to be elucidated. Copyright © 2016 Elsevier Inc. All rights reserved.

Multiple robustness in factorized likelihood models.

PubMed

Molina, J; Rotnitzky, A; Sued, M; Robins, J M

2017-09-01

We consider inference under a nonparametric or semiparametric model with likelihood that factorizes as the product of two or more variation-independent factors. We are interested in a finite-dimensional parameter that depends on only one of the likelihood factors and whose estimation requires the auxiliary estimation of one or several nuisance functions. We investigate general structures conducive to the construction of so-called multiply robust estimating functions, whose computation requires postulating several dimension-reducing models but which have mean zero at the true parameter value provided one of these models is correct.

[Factor associated with medicines utilization and expenditure in Mexico].

PubMed

Wirtz, Veronika J; Serván-Mori, Edson; Heredia-Pi, Ileana; Dreser, Anahí; Ávila-Burgos, Leticia

2013-01-01

To analyze medicine utilization and expenditure and associated factors in Mexico, as well as to discuss their implications for pharmaceutical policy. Analysis of a sample of 193,228 individuals from the Mexican National Health and Nutrition Survey 2012. Probability and amount of expenditure were estimated using logit, probit and quantile regression models, evaluating three dimensions of access to medicines: (1) likelihood of utilization of medicines in the event of a health problem, (2) probability of incurring expenses and (3) amount spent on medicines. Individuals affiliated to IMSS were more likely to use medicines (OR=1.2, p<0.05). Being affiliated to the IMSS, ISSSTE or SP reduced the likelihood of spending compared to those without health insurance (about RM 0.7, p<0.01). Median expenditures varied between 195.3 and 274.2 pesos. Factors associated with the use and expenditure on medicines indicate that inequities in the access to medicines persist.

Factors associated with seasonal influenza vaccination in pregnant women.

PubMed

Henninger, Michelle L; Irving, Stephanie A; Thompson, Mark; Avalos, Lyndsay Ammon; Ball, Sarah W; Shifflett, Pat; Naleway, Allison L

2015-05-01

This observational study followed a cohort of pregnant women during the 2010-2011 influenza season to determine factors associated with vaccination. Participants were 1105 pregnant women who completed a survey assessing health beliefs related to vaccination upon enrollment and were then followed to determine vaccination status by the end of the 2010-2011 influenza season. We conducted univariate and multivariate analyses to explore factors associated with vaccination status and a factor analysis of survey items to identify health beliefs associated with vaccination. Sixty-three percent (n=701) of the participants were vaccinated. In the univariate analyses, multiple factors were associated with vaccination status, including maternal age, race, marital status, educational level, and gravidity. Factor analysis identified two health belief factors associated with vaccination: participant's positive views (factor 1) and negative views (factor 2) of influenza vaccination. In a multivariate logistic regression model, factor 1 was associated with increased likelihood of vaccination (adjusted odds ratio [aOR]=2.18; 95% confidence interval [CI]=1.72-2.78), whereas factor 2 was associated with decreased likelihood of vaccination (aOR=0.36; 95% CI=0.28-0.46). After controlling for the two health belief factors in multivariate analyses, demographic factors significant in univariate analyses were no longer significant. Women who received a provider recommendation were about three times more likely to be vaccinated (aOR=3.14; 95% CI=1.99-4.96). Pregnant women's health beliefs about vaccination appear to be more important than demographic and maternal factors previously associated with vaccination status. Provider recommendation remains one of the most critical factors influencing vaccination during pregnancy.

Clustering of modifiable biobehavioral risk factors for chronic disease in US adults: a latent class analysis.

PubMed

Leventhal, Adam M; Huh, Jimi; Dunton, Genevieve F

2014-11-01

Examining the co-occurrence patterns of modifiable biobehavioral risk factors for deadly chronic diseases (e.g. cancer, cardiovascular disease, diabetes) can elucidate the etiology of risk factors and guide disease-prevention programming. The aims of this study were to (1) identify latent classes based on the clustering of five key biobehavioral risk factors among US adults who reported at least one risk factor and (2) explore the demographic correlates of the identified latent classes. Participants were respondents of the National Epidemiologic Survey of Alcohol and Related Conditions (2004-2005) with at least one of the following disease risk factors in the past year (N = 22,789), which were also the latent class indicators: (1) alcohol abuse/dependence, (2) drug abuse/dependence, (3) nicotine dependence, (4) obesity, and (5) physical inactivity. Housing sample units were selected to match the US National Census in location and demographic characteristics, with young adults oversampled. Participants were administered surveys by trained interviewers. Five latent classes were yielded: 'obese, active non-substance abusers' (23%); 'nicotine-dependent, active, and non-obese' (19%); 'active, non-obese alcohol abusers' (6%); 'inactive, non-substance abusers' (50%); and 'active, polysubstance abusers' (3.7%). Four classes were characterized by a 100% likelihood of having one risk factor coupled with a low or moderate likelihood of having the other four risk factors. The five classes exhibited unique demographic profiles. Risk factors may cluster together in a non-monotonic fashion, with the majority of the at-risk population of US adults expected to have a high likelihood of endorsing only one of these five risk factors. © Royal Society for Public Health 2013.

Modeling association among demographic parameters in analysis of open population capture-recapture data.

PubMed

Link, William A; Barker, Richard J

2005-03-01

We present a hierarchical extension of the Cormack-Jolly-Seber (CJS) model for open population capture-recapture data. In addition to recaptures of marked animals, we model first captures of animals and losses on capture. The parameter set includes capture probabilities, survival rates, and birth rates. The survival rates and birth rates are treated as a random sample from a bivariate distribution, thus the model explicitly incorporates correlation in these demographic rates. A key feature of the model is that the likelihood function, which includes a CJS model factor, is expressed entirely in terms of identifiable parameters; losses on capture can be factored out of the model. Since the computational complexity of classical likelihood methods is prohibitive, we use Markov chain Monte Carlo in a Bayesian analysis. We describe an efficient candidate-generation scheme for Metropolis-Hastings sampling of CJS models and extensions. The procedure is illustrated using mark-recapture data for the moth Gonodontis bidentata.

Modeling association among demographic parameters in analysis of open population capture-recapture data

USGS Publications Warehouse

Link, William A.; Barker, Richard J.

2005-01-01

We present a hierarchical extension of the Cormack–Jolly–Seber (CJS) model for open population capture–recapture data. In addition to recaptures of marked animals, we model first captures of animals and losses on capture. The parameter set includes capture probabilities, survival rates, and birth rates. The survival rates and birth rates are treated as a random sample from a bivariate distribution, thus the model explicitly incorporates correlation in these demographic rates. A key feature of the model is that the likelihood function, which includes a CJS model factor, is expressed entirely in terms of identifiable parameters; losses on capture can be factored out of the model. Since the computational complexity of classical likelihood methods is prohibitive, we use Markov chain Monte Carlo in a Bayesian analysis. We describe an efficient candidate-generation scheme for Metropolis–Hastings sampling of CJS models and extensions. The procedure is illustrated using mark-recapture data for the moth Gonodontis bidentata.

Breakfast patterns and their likelihood of increased risk of overweight/obesity and risk factors for metabolic syndrome in adults 19+ years: National Health and Nutrition Examination Survey 2001-2008

USDA-ARS?s Scientific Manuscript database

Little is known about the relationship of specific types of breakfast consumed and the risk of overweight/obesity or risk factors for metabolic syndrome. Cluster analysis using National Health and Nutrition Examination Survey 2001-2008 data identified 12 breakfast clusters—including no breakfast, in...

Voluntary sterilisation among Canadian women.

PubMed

De Wit, M; Rajulton, F

1991-07-01

Using data from the 1984 Canadian Fertility Survey, proportional hazards modelling was employed to determine factors associated with the likelihood of voluntary sterilisation among 5315 women of childbearing age, and the trends in timing and differences in the likelihood associated with different age cohorts. Multivariate analysis suggests that educational attainment, parity and duration since last birth at the time of sterilisation, religious commitment, province of residence and marital status at the time of sterilisation, are all important predictors. Education and parity attainment emerged as the best predictors of the timing of voluntary sterilisation in all age cohorts, but the contribution of other covariates varies between cohorts.

[Formula: see text]Parental ratings of daily behavior and child cognitive test performance after pediatric mild traumatic brain injury.

PubMed

Donders, Jacobus; DeWit, Christin

2017-07-01

This study aimed to evaluate the degree to which the Behavior Rating Inventory of Executive Function (BRIEF) and Child Behavior Checklist (CBCL) measure overlapping vs. distinct constructs in pediatric patients with mild traumatic brain injury (TBI), and to examine the demographic and injury correlates of such constructs as well as those of cognitive test performance. A total of 100 parents completed the BRIEF and the CBCL within 1 to 12 months after the injury of their child. Groups were contrasted based on the presence vs. absence of impairment on, respectively, the BRIEF and the CBCL. Exploratory maximum likelihood factor analysis was used to evaluate latent constructs. Correlates of the various factor scores were evaluated through regression analysis and contrasted with those of a test of verbal learning and memory.The results revealed that the BRIEF and the CBCL disagree about the presence vs. absence of impairment in about one quarter of cases. A prior history of attention deficit/hyperactivity disorder (ADHD) was associated with an increased likelihood of impairment on both the BRIEF and the CBCL, whereas prior outpatient psychiatric treatment was associated with the increased likelihood of selective impairment on the CBCL. Latent constructs manifested themselves along cognitive regulation, emotional adjustment and behavioral regulation factors. Whereas premorbid characteristics were the exclusive correlates of these factors, performance on a test of verbal learning and memory was negatively affected by intracranial lesions on neuroimaging.It is concluded that the BRIEF and the CBCL offer complementary and non-redundant information about daily functioning after pediatric mild TBI. The correlates of cognitive test performance and parental behavior ratings after such injuries are different and reflect a divergence between premorbid and injury-related influences.

Prevalence and factors associated with non-utilization of healthcare facility for childbirth in rural and urban Nigeria: Analysis of a national population-based survey.

PubMed

Adewuyi, Emmanuel O; Zhao, Yun; Auta, Asa; Lamichhane, Reeta

2017-08-01

The aim of this study was to assess the rural-urban differences in the prevalence and factors associated with non-utilization of healthcare facility for childbirth (home delivery) in Nigeria. Dataset from the Nigeria demographic and health survey, 2013, disaggregated by rural-urban residence were analyzed with appropriate adjustment for the cluster sampling design of the survey. Factors associated with home delivery were identified using multivariable logistic regression analysis. In rural and urban residence, the prevalence of home delivery were 78.3% and 38.1%, respectively ( p < 0.001). The lowest prevalence of home delivery occurred in the South-East region for rural residence (18.6%) and the South-West region for urban residence (17.9%). The North-West region had the highest prevalence of home delivery, 93.6% and 70.5% in rural and urban residence, respectively. Low maternal as well as paternal education, low antenatal attendance, being less wealthy, the practice of Islam, and living in the North-East, North-West and the South-South regions increased the likelihood of home delivery in both rural and urban residences. Whether in rural or urban residence, birth order of one decreased the likelihood of home delivery. In rural residence only, living in the North-Central region increased the chances of home delivery. In urban residence only, maternal age ⩾ 36 years decreased the likelihood of home delivery, while 'Traditionalist/other' religion and maternal age < 20 years increased it. The prevalence of home delivery was much higher in rural than urban Nigeria and the associated factors differ to varying degrees in the two residences. Future intervention efforts would need to prioritize findings in this study.

Interactive effects of work psychosocial factors on participation in workplace wellness programs.

PubMed

Sangachin, Mahboobeh Ghesmaty; Cavuoto, Lora A

2018-01-01

This study explored concurrent effects of six work psychosocial factors on current participation and the self-reported likelihood of future participation in workplace wellness programs using a cross-sectional survey, an ad hoc focus group, and structured interviews. Classification and regression tree analysis was used to analyze survey responses from 343 employees (194 nonparticipants, 95 participants, and 54 engaged participants). A thematic analysis of focus group ( n = 7) and interview ( n = 5) narratives was also undertaken. In combination with high work control, high superior support was associated with an engaged participant profile. Job demand was the third important variable with low and very high levels associated with participation. With regard to high likelihood of future participation, among respondents with age older than 50, high predictability of occupational activities and control were identified as a significant factor, and among others, high superior support and control. The analysis of narratives revealed peer relations and flexible working hours to be positively linked to participation and general job stress was identified as having a bidirectional relationship. Employees stated that stress led them to take advantage of these programs as a source of relief and that their availability/participation has contributed to lowering their stress. These findings inform practitioners about the importance of addressing poor psychosocial factors as a participation barrier and having a holistic approach to employee well-being.

Factors associated with survival of epiploic foramen entrapment colic: a multicentre, international study.

PubMed

Archer, D C; Pinchbeck, G L; Proudman, C J

2011-08-01

Epiploic foramen entrapment (EFE) has been associated with reduced post operative survival compared to other types of colic but specific factors associated with reduced long-term survival of these cases have not been evaluated in a large number of horses using survival analysis. To describe post operative survival of EFE cases and to identify factors associated with long-term survival. A prospective, multicentre, international study was conducted using clinical data and long-term follow-up information for 126 horses diagnosed with EFE during exploratory laparotomy at 15 clinics in the UK, Ireland and USA. Descriptive data were generated and survival analysis performed to identify factors associated with reduced post operative survival. For the EFE cohort that recovered following anaesthesia, survival to hospital discharge was 78.5%. Survival to 1 and 2 years post operatively was 50.6 and 34.3%, respectively. The median survival time of EFE cases undergoing surgery was 397 days. Increased packed cell volume (PCV) and increased length of small intestine (SI) resected were significantly associated with increased likelihood of mortality when multivariable analysis of pre- and intraoperative variables were analysed. When all pre-, intra- and post operative variables were analysed separately, only horses that developed post operative ileus (POI) were shown to be at increased likelihood of mortality. Increased PCV, increased length of SI resected and POI are all associated with increased likelihood of mortality of EFE cases. This emphasises the importance of early diagnosis and treatment and the need for improved strategies in the management of POI in order to reduce post operative mortality in these cases. The present study provides evidence-based information to clinicians and owners of horses undergoing surgery for EFE about long-term survival. These results are applicable to university and large private clinics over a wide geographical area. © 2011 EVJ Ltd.

Section 9: Ground Water - Likelihood of Release

EPA Pesticide Factsheets

HRS training. the ground water pathway likelihood of release factor category reflects the likelihood that there has been, or will be, a release of hazardous substances in any of the aquifers underlying the site.

Contributing factors to vehicle to vehicle crash frequency and severity under rainfall.

PubMed

Jung, Soyoung; Jang, Kitae; Yoon, Yoonjin; Kang, Sanghyeok

2014-09-01

This study combined vehicle to vehicle crash frequency and severity estimations to examine factor impacts on Wisconsin highway safety in rainy weather. Because of data deficiency, the real-time water film depth, the car-following distance, and the vertical curve grade were estimated with available data sources and a GIS analysis to capture rainy weather conditions at the crash location and time. Using a negative binomial regression for crash frequency estimation, the average annual daily traffic per lane, the interaction between the posted speed limit change and the existence of an off-ramp, and the interaction between the travel lane number change and the pavement surface material change were found to increase the likelihood of vehicle to vehicle crashes under rainfall. However, more average daily rainfall per month and a wider left shoulder were identified as factors that decrease the likelihood of vehicle to vehicle crashes. In the crash severity estimation using the multinomial logit model that outperformed the ordered logit model, the travel lane number, the interaction between the travel lane number and the slow grade, the deep water film, and the rear-end collision type were more likely to increase the likelihood of injury crashes under rainfall compared with crashes involving only property damage. As an exploratory data analysis, this study provides insight into potential strategies for rainy weather highway safety improvement, specifically, the following weather-sensitive strategies: road design and ITS implementation for drivers' safety awareness under rainfall. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

Prospective Risk Factors for Adolescent PTSD: Sources of Differential Exposure and Differential Vulnerability

ERIC Educational Resources Information Center

Milan, Stephanie; Zona, Kate; Acker, Jenna; Turcios-Cotto, Viana

2013-01-01

There are two types of risk factors for developing PTSD: factors that increase the likelihood of experiencing a potentially traumatizing event and factors that increase the likelihood of developing symptoms following such events. Using prospective data over a two-year period from a large, diverse sample of urban adolescents (n = 1242, Mean age =…

Sustainability likelihood of remediation options for metal-contaminated soil/sediment.

PubMed

Chen, Season S; Taylor, Jessica S; Baek, Kitae; Khan, Eakalak; Tsang, Daniel C W; Ok, Yong Sik

2017-05-01

Multi-criteria analysis and detailed impact analysis were carried out to assess the sustainability of four remedial alternatives for metal-contaminated soil/sediment at former timber treatment sites and harbour sediment with different scales. The sustainability was evaluated in the aspects of human health and safety, environment, stakeholder concern, and land use, under four different scenarios with varying weighting factors. The Monte Carlo simulation was performed to reveal the likelihood of accomplishing sustainable remediation with different treatment options at different sites. The results showed that in-situ remedial technologies were more sustainable than ex-situ ones, where in-situ containment demonstrated both the most sustainable result and the highest probability to achieve sustainability amongst the four remedial alternatives in this study, reflecting the lesser extent of off-site and on-site impacts. Concerns associated with ex-situ options were adverse impacts tied to all four aspects and caused by excavation, extraction, and off-site disposal. The results of this study suggested the importance of considering the uncertainties resulting from the remedial options (i.e., stochastic analysis) in addition to the overall sustainability scores (i.e., deterministic analysis). The developed framework and model simulation could serve as an assessment for the sustainability likelihood of remedial options to ensure sustainable remediation of contaminated sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preoperative Serum Thyrotropin to Thyroglobulin Ratio Is Effective for Thyroid Nodule Evaluation in Euthyroid Patients.

PubMed

Wang, Lina; Li, Hao; Yang, Zhongyuan; Guo, Zhuming; Zhang, Quan

2015-07-01

This study was designed to assess the efficiency of the serum thyrotropin to thyroglobulin ratio for thyroid nodule evaluation in euthyroid patients. Cross-sectional study. Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China. Retrospective analysis was performed for 400 previously untreated cases presenting with thyroid nodules. Thyroid function was tested with commercially available radioimmunoassays. The receiver operating characteristic curves were constructed to determine cutoff values. The efficacy of the thyrotropin:thyroglobulin ratio and thyroid-stimulating hormone for thyroid nodule evaluation was evaluated in terms of sensitivity, specificity, positive predictive value, positive likelihood ratio, negative likelihood ratio, and odds ratio. In receiver operating characteristic curve analysis, the area under the curve was 0.746 for the thyrotropin:thyroglobulin ratio and 0.659 for thyroid-stimulating hormone. With a cutoff point value of 24.97 IU/g for the thyrotropin:thyroglobulin ratio, the sensitivity, specificity, positive predictive value, positive likelihood ratio, and negative likelihood ratio were 78.9%, 60.8%, 75.5%, 2.01, and 0.35, respectively. The odds ratio for the thyrotropin:thyroglobulin ratio indicating malignancy was 5.80. With a cutoff point value of 1.525 µIU/mL for thyroid-stimulating hormone, the sensitivity, specificity, positive predictive value, positive likelihood ratio, and negative likelihood ratio were 74.0%, 53.2%, 70.8%, 1.58, and 0.49, respectively. The odds ratio indicating malignancy for thyroid-stimulating hormone was 3.23. Increasing preoperative serum thyrotropin:thyroglobulin ratio is a risk factor for thyroid carcinoma, and the correlation of the thyrotropin:thyroglobulin ratio to malignancy is higher than that for serum thyroid-stimulating hormone. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Multisite-multivariable sensitivity analysis of distributed watershed models: enhancing the perceptions from computationally frugal methods

USDA-ARS?s Scientific Manuscript database

This paper assesses the impact of different likelihood functions in identifying sensitive parameters of the highly parameterized, spatially distributed Soil and Water Assessment Tool (SWAT) watershed model for multiple variables at multiple sites. The global one-factor-at-a-time (OAT) method of Morr...

Measures of Overweight Status in School-Age Children

ERIC Educational Resources Information Center

Skybo, Theresa; Ryan-Wenger, Nancy

2003-01-01

Identifying and intervening with overweight children may decrease their likelihood of developing heart disease later in life. This secondary analysis of 58 children in the 3rd grade examined the prevalence of overweight children, methods for measuring overweight status, and the relationship among these measures and other risk factors for heart…

Factors associated with aggressive behavior between residents and staff in nursing homes.

PubMed

Stutte, Karin; Hahn, Sabine; Fierz, Katharina; Zúñiga, Franziska

The aim of this secondary data analysis of the cross-sectional Swiss Nursing Homes Human Resources Project (SHURP) study was to describe the prevalence of residents' verbal, physical and sexual aggression toward care workers in Swiss nursing homes and to explore their association with context and care worker factors. The study's sample incorporated data from 155 randomly selected nursing homes, including 402 units. Among care workers (n = 3919), 66% reported experiencing verbal, 42% physical and 15% sexual aggression. Logistic regression analyses indicated that non-special care units and care workers' higher perception of staffing and resources adequacy and higher age were associated with a decreased likelihood of aggression, whereas emotional exhaustion was associated with an increased likelihood. Our results suggest an association of aggressive resident behavior with modifiable context and care worker factors. Knowledge about this may contribute to a continuous improvement process, enhancing residents' well-being alongside care workers' safety and satisfaction. Copyright © 2017 Elsevier Inc. All rights reserved.

Meta-Analysis and Systematic Review to Assess the Role of Soluble FMS-Like Tyrosine Kinase-1 and Placenta Growth Factor Ratio in Prediction of Preeclampsia: The SaPPPhirE Study.

PubMed

Agrawal, Swati; Cerdeira, Ana Sofia; Redman, Christopher; Vatish, Manu

2018-02-01

Preeclampsia is a major cause of morbidity and mortality worldwide. Numerous candidate biomarkers have been proposed for diagnosis and prediction of preeclampsia. Measurement of maternal circulating angiogenesis biomarker as the ratio of sFlt-1 (soluble FMS-like tyrosine kinase-1; an antiangiogenic factor)/PlGF (placental growth factor; an angiogenic factor) reflects the antiangiogenic balance that characterizes incipient or overt preeclampsia. The ratio increases before the onset of the disease and thus may help in predicting preeclampsia. We conducted a meta-analysis to explore the predictive accuracy of sFlt-1/PlGF ratio in preeclampsia. We included 15 studies with 534 cases with preeclampsia and 19 587 controls. The ratio has a pooled sensitivity of 80% (95% confidence interval, 0.68-0.88), specificity of 92% (95% confidence interval, 0.87-0.96), positive likelihood ratio of 10.5 (95% confidence interval, 6.2-18.0), and a negative likelihood ratio of 0.22 (95% confidence interval, 0.13-0.35) in predicting preeclampsia in both high- and low-risk patients. Most of the studies have not made a distinction between early- and late-onset disease, and therefore, the analysis for it could not be done. It can prove to be a valuable screening tool for preeclampsia and may also help in decision-making, treatment stratification, and better resource allocation. © 2017 American Heart Association, Inc.

Weapon carrying and psychopathic-like features in a population-based sample of Finnish adolescents.

PubMed

Saukkonen, Suvi; Laajasalo, Taina; Jokela, Markus; Kivivuori, Janne; Salmi, Venla; Aronen, Eeva T

2016-02-01

We investigated the prevalence of juvenile weapon carrying and psychosocial and personality-related risk factors for carrying different types of weapons in a nationally representative, population-based sample of Finnish adolescents. Specifically, we aimed to investigate psychopathic-like personality features as a risk factor for weapon carrying. The participants were 15-16-year-old adolescents from the Finnish self-report delinquency study (n = 4855). Four different groups were formed based on self-reported weapon carrying: no weapon carrying, carrying knife, gun or other weapon. The associations between psychosocial factors, psychopathic-like features and weapon carrying were examined with multinomial logistic regression analysis. 9% of the participants had carried a weapon in the past 12 months. Adolescents with a history of delinquency, victimization and antisocial friends were more likely to carry weapons in general; however, delinquency and victimization were most strongly related to gun carrying, while perceived peer delinquency (antisocial friends) was most strongly related to carrying a knife. Better academic performance was associated with a reduced likelihood of carrying a gun and knife, while feeling secure correlated with a reduced likelihood of gun carrying only. Psychopathic-like features were related to a higher likelihood of weapon carrying, even after adjusting for other risk factors. The findings of the study suggest that adolescents carrying a weapon have a large cluster of problems in their lives, which may vary based on the type of weapon carried. Furthermore, psychopathic-like features strongly relate to a higher risk of carrying a weapon.

Important factors in the maximum likelihood analysis of flight test maneuvers

NASA Technical Reports Server (NTRS)

Iliff, K. W.; Maine, R. E.; Montgomery, T. D.

1979-01-01

The information presented is based on the experience in the past 12 years at the NASA Dryden Flight Research Center of estimating stability and control derivatives from over 3500 maneuvers from 32 aircraft. The overall approach to the analysis of dynamic flight test data is outlined. General requirements for data and instrumentation are discussed and several examples of the types of problems that may be encountered are presented.

Maximum Likelihood Dynamic Factor Modeling for Arbitrary "N" and "T" Using SEM

ERIC Educational Resources Information Center

Voelkle, Manuel C.; Oud, Johan H. L.; von Oertzen, Timo; Lindenberger, Ulman

2012-01-01

This article has 3 objectives that build on each other. First, we demonstrate how to obtain maximum likelihood estimates for dynamic factor models (the direct autoregressive factor score model) with arbitrary "T" and "N" by means of structural equation modeling (SEM) and compare the approach to existing methods. Second, we go beyond standard time…

Confirmatory Factor Analysis of Ordinal Variables with Misspecified Models

ERIC Educational Resources Information Center

Yang-Wallentin, Fan; Joreskog, Karl G.; Luo, Hao

2010-01-01

Ordinal variables are common in many empirical investigations in the social and behavioral sciences. Researchers often apply the maximum likelihood method to fit structural equation models to ordinal data. This assumes that the observed measures have normal distributions, which is not the case when the variables are ordinal. A better approach is…

Predictors of Home Radon Testing and Implications for Testing Promotion Programs.

ERIC Educational Resources Information Center

Sandman, Peter M.; Weinstein, Neil D.

1993-01-01

Analysis of 4 New Jersey studies of 3,329 homeowners found that (1) thinking about radon testing is predicted by general radon knowledge; (2) decision to test is related to perceived likelihood of risk; and (3) actual testing is influenced by situational factors such as locating and choosing test kits. (SK)

Analyzing seasonal patterns of wildfire exposure factors in Sardinia, Italy

Treesearch

Michele Salis; Alan A. Ager; Fermin J. Alcasena; Bachisio Arca; Mark A. Finney; Grazia Pellizzaro; Donatella Spano

2015-01-01

In this paper, we applied landscape scale wildfire simulation modeling to explore the spatiotemporal patterns of wildfire likelihood and intensity in the island of Sardinia (Italy). We also performed wildfire exposure analysis for selected highly valued resources on the island to identify areas characterized by high risk. We observed substantial variation in burn...

A Social Psychological Model for Predicting Sexual Harassment.

ERIC Educational Resources Information Center

Pryor, John B.; And Others

1995-01-01

Presents a Person X Situation (PXS) model of sexual harassment suggesting that sexually harassing behavior may be predicted from an analysis of social situational and personal factors. Research on sexual harassment proclivities in men is reviewed, and a profile of men who have a high a likelihood to sexually harass is discussed. Possible PXS…

Campaign Strategies and Voter Approval of School Referenda: A Mixed Methods Analysis

ERIC Educational Resources Information Center

Johnson, Paul A.; Ingle, William Kyle

2009-01-01

Drawing from state administrative data and surveys of superintendents in Ohio, this mixed methods study examined factors associated with voters' approval of local school levies. Utilizing binomial logistic regression, this study found that new levies and poverty rates were significantly associated with a decrease in the likelihood of passage.…

Three regularities of recognition memory: the role of bias.

PubMed

Hilford, Andrew; Maloney, Laurence T; Glanzer, Murray; Kim, Kisok

2015-12-01

A basic assumption of Signal Detection Theory is that decisions are made on the basis of likelihood ratios. In a preceding paper, Glanzer, Hilford, and Maloney (Psychonomic Bulletin & Review, 16, 431-455, 2009) showed that the likelihood ratio assumption implies that three regularities will occur in recognition memory: (1) the Mirror Effect, (2) the Variance Effect, (3) the normalized Receiver Operating Characteristic (z-ROC) Length Effect. The paper offered formal proofs and computational demonstrations that decisions based on likelihood ratios produce the three regularities. A survey of data based on group ROCs from 36 studies validated the likelihood ratio assumption by showing that its three implied regularities are ubiquitous. The study noted, however, that bias, another basic factor in Signal Detection Theory, can obscure the Mirror Effect. In this paper we examine how bias affects the regularities at the theoretical level. The theoretical analysis shows: (1) how bias obscures the Mirror Effect, not the other two regularities, and (2) four ways to counter that obscuring. We then report the results of five experiments that support the theoretical analysis. The analyses and the experimental results also demonstrate: (1) that the three regularities govern individual, as well as group, performance, (2) alternative explanations of the regularities are ruled out, and (3) that Signal Detection Theory, correctly applied, gives a simple and unified explanation of recognition memory data.

Factors Associated with Young Adults’ Pregnancy Likelihood

PubMed Central

Kitsantas, Panagiota; Lindley, Lisa L.; Wu, Huichuan

2014-01-01

OBJECTIVES While progress has been made to reduce adolescent pregnancies in the United States, rates of unplanned pregnancy among young adults (18–29 years) remain high. In this study, we assessed factors associated with perceived likelihood of pregnancy (likelihood of getting pregnant/getting partner pregnant in the next year) among sexually experienced young adults who were not trying to get pregnant and had ever used contraceptives. METHODS We conducted a secondary analysis of 660 young adults, 18–29 years old in the United States, from the cross-sectional National Survey of Reproductive and Contraceptive Knowledge. Logistic regression and classification tree analyses were conducted to generate profiles of young adults most likely to report anticipating a pregnancy in the next year. RESULTS Nearly one-third (32%) of young adults indicated they believed they had at least some likelihood of becoming pregnant in the next year. Young adults who believed that avoiding pregnancy was not very important were most likely to report pregnancy likelihood (odds ratio [OR], 5.21; 95% CI, 2.80–9.69), as were young adults for whom avoiding a pregnancy was important but not satisfied with their current contraceptive method (OR, 3.93; 95% CI, 1.67–9.24), attended religious services frequently (OR, 3.0; 95% CI, 1.52–5.94), were uninsured (OR, 2.63; 95% CI, 1.31–5.26), and were likely to have unprotected sex in the next three months (OR, 1.77; 95% CI, 1.04–3.01). DISCUSSION These results may help guide future research and the development of pregnancy prevention interventions targeting sexually experienced young adults. PMID:25782849

Two simple clinical tests for predicting onset of medial tibial stress syndrome: shin palpation test and shin oedema test.

PubMed

Newman, Phil; Adams, Roger; Waddington, Gordon

2012-09-01

To examine the relationship between two clinical test results and future diagnosis of (Medial Tibial Stress Syndrome) MTSS in personnel at a military trainee establishment. Data from a preparticipation musculoskeletal screening test performed on 384 Australian Defence Force Academy Officer Cadets were compared against 693 injuries reported by 326 of the Officer Cadets in the following 16 months. Data were held in an Injury Surveillance database and analysed using χ² and Fisher's Exact tests, and Receiver Operating Characteristic Curve analysis. Diagnosis of MTSS, confirmed by an independent blinded health practitioner. Both the palpation and oedema clinical tests were each found to be significant predictors for later onset of MTSS. Specifically: Shin palpation test OR 4.63, 95% CI 2.5 to 8.5, Positive Likelihood Ratio 3.38, Negative Likelihood Ratio 0.732, Pearson χ² p<0.001; Shin oedema test OR 76.1 95% CI 9.6 to 602.7, Positive Likelihood Ratio 7.26, Negative Likelihood Ratio 0.095, Fisher's Exact p<0.001; Combined Shin Palpation Test and Shin Oedema Test Positive Likelihood Ratio 7.94, Negative Likelihood Ratio <0.001, Fisher's Exact p<0.001. Female gender was found to be an independent risk factor (OR 2.97, 95% CI 1.66 to 5.31, Positive Likelihood Ratio 2.09, Negative Likelihood Ratio 0.703, Pearson χ² p<0.001) for developing MTSS. The tests for MTSS employed here are components of a normal clinical examination used to diagnose MTSS. This paper confirms that these tests and female gender can also be confidently applied in predicting those in an asymptomatic population who are at greater risk of developing MTSS symptoms with activity at some point in the future.

A score to estimate the likelihood of detecting advanced colorectal neoplasia at colonoscopy

PubMed Central

Kaminski, Michal F; Polkowski, Marcin; Kraszewska, Ewa; Rupinski, Maciej; Butruk, Eugeniusz; Regula, Jaroslaw

2014-01-01

Objective This study aimed to develop and validate a model to estimate the likelihood of detecting advanced colorectal neoplasia in Caucasian patients. Design We performed a cross-sectional analysis of database records for 40-year-old to 66-year-old patients who entered a national primary colonoscopy-based screening programme for colorectal cancer in 73 centres in Poland in the year 2007. We used multivariate logistic regression to investigate the associations between clinical variables and the presence of advanced neoplasia in a randomly selected test set, and confirmed the associations in a validation set. We used model coefficients to develop a risk score for detection of advanced colorectal neoplasia. Results Advanced colorectal neoplasia was detected in 2544 of the 35 918 included participants (7.1%). In the test set, a logistic-regression model showed that independent risk factors for advanced colorectal neoplasia were: age, sex, family history of colorectal cancer, cigarette smoking (p<0.001 for these four factors), and Body Mass Index (p=0.033). In the validation set, the model was well calibrated (ratio of expected to observed risk of advanced neoplasia: 1.00 (95% CI 0.95 to 1.06)) and had moderate discriminatory power (c-statistic 0.62). We developed a score that estimated the likelihood of detecting advanced neoplasia in the validation set, from 1.32% for patients scoring 0, to 19.12% for patients scoring 7–8. Conclusions Developed and internally validated score consisting of simple clinical factors successfully estimates the likelihood of detecting advanced colorectal neoplasia in asymptomatic Caucasian patients. Once externally validated, it may be useful for counselling or designing primary prevention studies. PMID:24385598

A score to estimate the likelihood of detecting advanced colorectal neoplasia at colonoscopy.

PubMed

Kaminski, Michal F; Polkowski, Marcin; Kraszewska, Ewa; Rupinski, Maciej; Butruk, Eugeniusz; Regula, Jaroslaw

2014-07-01

This study aimed to develop and validate a model to estimate the likelihood of detecting advanced colorectal neoplasia in Caucasian patients. We performed a cross-sectional analysis of database records for 40-year-old to 66-year-old patients who entered a national primary colonoscopy-based screening programme for colorectal cancer in 73 centres in Poland in the year 2007. We used multivariate logistic regression to investigate the associations between clinical variables and the presence of advanced neoplasia in a randomly selected test set, and confirmed the associations in a validation set. We used model coefficients to develop a risk score for detection of advanced colorectal neoplasia. Advanced colorectal neoplasia was detected in 2544 of the 35,918 included participants (7.1%). In the test set, a logistic-regression model showed that independent risk factors for advanced colorectal neoplasia were: age, sex, family history of colorectal cancer, cigarette smoking (p<0.001 for these four factors), and Body Mass Index (p=0.033). In the validation set, the model was well calibrated (ratio of expected to observed risk of advanced neoplasia: 1.00 (95% CI 0.95 to 1.06)) and had moderate discriminatory power (c-statistic 0.62). We developed a score that estimated the likelihood of detecting advanced neoplasia in the validation set, from 1.32% for patients scoring 0, to 19.12% for patients scoring 7-8. Developed and internally validated score consisting of simple clinical factors successfully estimates the likelihood of detecting advanced colorectal neoplasia in asymptomatic Caucasian patients. Once externally validated, it may be useful for counselling or designing primary prevention studies. 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.

Traumatic physical health consequences of intimate partner violence against women: what is the role of community-level factors?

PubMed Central

2011-01-01

Background Intimate partner violence (IPV) against women is a serious public health issue with recognizable direct health consequences. This study assessed the association between IPV and traumatic physical health consequences on women in Nigeria, given that communities exert significant influence on the individuals that are embedded within them, with the nature of influence varying between communities. Methods Cross-sectional nationally-representative data of women aged 15 - 49 years in the 2008 Nigeria Demographic and Health Survey was used in this study. Multilevel logistic regression analysis was used to assess the association between IPV and several forms of physical health consequences. Results Bruises were the most common form of traumatic physical health consequences. In the adjusted models, the likelihood of sustaining bruises (OR = 1.91, 95% CI = 1.05 - 3.46), wounds (OR = 2.54, 95% CI = 1.31 - 4.95), and severe burns (OR = 3.20, 95% CI = 1.63 - 6.28) was significantly higher for women exposed to IPV compared to those not exposed to IPV. However, after adjusting for individual- and community-level factors, women with husbands/partners with controlling behavior, those with primary or no education, and those resident in communities with high tolerance for wife beating had a higher likelihood of experiencing IPV, whilst mean community-level education and women 24 years or younger were at lower likelihood of experiencing IPV. Conclusions Evidence from this study shows that exposure to IPV is associated with increased likelihood of traumatic physical consequences for women in Nigeria. Education and justification of wife beating were significant community-level factors associated with traumatic physical consequences, suggesting the importance of increasing women's levels of education and changing community norms that justify controlling behavior and IPV. PMID:22185323

Determinants of under-five mortality in rural and urban Kenya.

PubMed

Ettarh, R R; Kimani, J

2012-01-01

The disparity in under-five year-old mortality rates between rural and urban areas in Kenya (also reported in other in sub-Saharan African countries), is a critical national concern. The objective of this study was to investigate the influence of geographical location and maternal factors on the likelihood of mortality among under-five children in rural and urban areas in Kenya. Data from the 2008-2009 Kenya Demographic and Health Survey were used to determine mortality among under-five children (n=16,162) in rural and urban areas in the 5 years preceding the survey. Multivariate analysis was used to compare the influence of key risk factors in rural and urban areas. Overall, the likelihood of death among under-five children in the rural areas was significantly higher than that in the urban areas (p<0.05). Household poverty was a key predictor for mortality in the rural areas, but the influence of breastfeeding was similar in the two areas. The likelihood of under-five mortality was significantly higher in the rural areas of Coast, Nyanza and Western Provinces than in Central Province. The study shows that the determinants of under-five mortality differ in rural and urban areas in Kenya. Innovative and targeted strategies are required to address rural poverty and province-specific sociocultural factors in order to improve child survival in rural Kenya.

Synthesizing Regression Results: A Factored Likelihood Method

ERIC Educational Resources Information Center

Wu, Meng-Jia; Becker, Betsy Jane

2013-01-01

Regression methods are widely used by researchers in many fields, yet methods for synthesizing regression results are scarce. This study proposes using a factored likelihood method, originally developed to handle missing data, to appropriately synthesize regression models involving different predictors. This method uses the correlations reported…

Quality failures in residential aged care in Australia: The relationship between structural factors and regulation imposed sanctions.

PubMed

Baldwin, Richard; Chenoweth, Lynnette; Dela Rama, Marie; Liu, Zhixin

2015-12-01

To examine the relationship between structural factors and the imposition of sanctions on residential aged care services across Australia for regulatory compliance failure. Poisson Regression analysis was used to examine the association between the number of sanctions imposed and the structural characteristics of residential aged care services in Australia. Residential aged care services that have a greater likelihood of having government sanctions imposed on them are operated by for-profit providers and located in remote locations and in Victoria, Queensland, South Australia, Northern Territory and the Australian Capital Territory. The findings confirm the international literature on the relationship between residential aged care service location, ownership type and the likelihood of sanctions. In the light of the predicted expansion of residential aged care services, policy makers should give consideration to structural elements most likely to be associated with a failure to meet and maintain service standards. © 2014 ACOTA.

Family cohesion moderates the relationship between acculturative stress and depression in Japanese adolescent temporary residents.

PubMed

Roley, Michelle E; Kawakami, Ryoko; Baker, Jessica; Hurtado, Gabriela; Chin, Andrew; Hovey, Joseph D

2014-12-01

Acculturative stress is a risk factor for depression, and may be important in the risk for depression among acculturating Japanese adolescents. However, little to no research has been published on the mental health of acculturating Japanese adolescents. Further, although family cohesion has been shown to be protective against depression across ethnic groups, no prior research has examined family cohesion as a protective factor for Japanese adolescents. To examine these relationships, 26 Japanese temporary resident adolescents and 76 parents in the Midwest were recruited to participate. Moderate to strong correlations between acculturative stress, depression, likelihood for and seriousness of family conflict were found. A regression analysis found that likelihood for family conflict moderated the relationship between acculturative stress and depression. Findings broaden our understanding of the role of acculturative stress and family conflict on depression risk for Japanese adolescent immigrants.

Exact likelihood evaluations and foreground marginalization in low resolution WMAP data

NASA Astrophysics Data System (ADS)

Slosar, Anže; Seljak, Uroš; Makarov, Alexey

2004-06-01

The large scale anisotropies of Wilkinson Microwave Anisotropy Probe (WMAP) data have attracted a lot of attention and have been a source of controversy, with many favorite cosmological models being apparently disfavored by the power spectrum estimates at low l. All the existing analyses of theoretical models are based on approximations for the likelihood function, which are likely to be inaccurate on large scales. Here we present exact evaluations of the likelihood of the low multipoles by direct inversion of the theoretical covariance matrix for low resolution WMAP maps. We project out the unwanted galactic contaminants using the WMAP derived maps of these foregrounds. This improves over the template based foreground subtraction used in the original analysis, which can remove some of the cosmological signal and may lead to a suppression of power. As a result we find an increase in power at low multipoles. For the quadrupole the maximum likelihood values are rather uncertain and vary between 140 and 220 μK2. On the other hand, the probability distribution away from the peak is robust and, assuming a uniform prior between 0 and 2000 μK2, the probability of having the true value above 1200 μK2 (as predicted by the simplest cold dark matter model with a cosmological constant) is 10%, a factor of 2.5 higher than predicted by the WMAP likelihood code. We do not find the correlation function to be unusual beyond the low quadrupole value. We develop a fast likelihood evaluation routine that can be used instead of WMAP routines for low l values. We apply it to the Markov chain Monte Carlo analysis to compare the cosmological parameters between the two cases. The new analysis of WMAP either alone or jointly with the Sloan Digital Sky Survey (SDSS) and the Very Small Array (VSA) data reduces the evidence for running to less than 1σ, giving αs=-0.022±0.033 for the combined case. The new analysis prefers about a 1σ lower value of Ωm, a consequence of an increased integrated Sachs-Wolfe (ISW) effect contribution required by the increase in the spectrum at low l. These results suggest that the details of foreground removal and full likelihood analysis are important for parameter estimation from the WMAP data. They are robust in the sense that they do not change significantly with frequency, mask, or details of foreground template marginalization. The marginalization approach presented here is the most conservative method to remove the foregrounds and should be particularly useful in the analysis of polarization, where foreground contamination may be much more severe.

The retention of health human resources in primary healthcare centers in Lebanon: a national survey.

PubMed

Alameddine, Mohamad; Saleh, Shadi; El-Jardali, Fadi; Dimassi, Hani; Mourad, Yara

2012-11-22

Critical shortages of health human resources (HHR), associated with high turnover rates, have been a concern in many countries around the globe. Of particular interest is the effect of such a trend on the primary healthcare (PHC) sector; considered a cornerstone in any effective healthcare system. This study is a rare attempt to investigate PHC HHR work characteristics, level of burnout and likelihood to quit as well as the factors significantly associated with staff retention at PHC centers in Lebanon. A cross-sectional design was utilized to survey all health providers at 81 PHC centers dispersed in all districts of Lebanon. The questionnaire consisted of four sections: socio-demographic/ professional background, organizational/institutional characteristics, likelihood to quit and level of professional burnout (using the Maslach-Burnout Inventory). A total of 755 providers completed the questionnaire (60.5% response rate). Bivariate analyses and multinomial logistic regression were used to determine factors associated with likelihood to quit. Two out of five respondents indicated likelihood to quit their jobs within the next 1-3 years and an additional 13.4% were not sure about quitting. The top three reasons behind likelihood to quit were poor salary (54.4%), better job opportunities outside the country (35.1%) and lack of professional development (33.7%). A U-shaped relationship was observed between age and likelihood to quit. Regression analysis revealed that high levels of burnout, lower level of education and low tenure were all associated with increased likelihood to quit. The study findings reflect an unstable workforce and are not conducive to supporting an expanded role for PHC in the Lebanese healthcare system. While strategies aiming at improving staff retention would be important to develop and implement for all PHC HHR; targeted retention initiatives should focus on the young-new recruits and allied health professionals. Particular attention should be dedicated to enhancing providers' role satisfaction and sense of job security. Such initiatives are of pivotal importance to stabilize the workforce and ensure its longevity.

The retention of health human resources in primary healthcare centers in Lebanon: a national survey

PubMed Central

2012-01-01

Background Critical shortages of health human resources (HHR), associated with high turnover rates, have been a concern in many countries around the globe. Of particular interest is the effect of such a trend on the primary healthcare (PHC) sector; considered a cornerstone in any effective healthcare system. This study is a rare attempt to investigate PHC HHR work characteristics, level of burnout and likelihood to quit as well as the factors significantly associated with staff retention at PHC centers in Lebanon. Methods A cross-sectional design was utilized to survey all health providers at 81 PHC centers dispersed in all districts of Lebanon. The questionnaire consisted of four sections: socio-demographic/ professional background, organizational/institutional characteristics, likelihood to quit and level of professional burnout (using the Maslach-Burnout Inventory). A total of 755 providers completed the questionnaire (60.5% response rate). Bivariate analyses and multinomial logistic regression were used to determine factors associated with likelihood to quit. Results Two out of five respondents indicated likelihood to quit their jobs within the next 1–3 years and an additional 13.4% were not sure about quitting. The top three reasons behind likelihood to quit were poor salary (54.4%), better job opportunities outside the country (35.1%) and lack of professional development (33.7%). A U-shaped relationship was observed between age and likelihood to quit. Regression analysis revealed that high levels of burnout, lower level of education and low tenure were all associated with increased likelihood to quit. Conclusions The study findings reflect an unstable workforce and are not conducive to supporting an expanded role for PHC in the Lebanese healthcare system. While strategies aiming at improving staff retention would be important to develop and implement for all PHC HHR; targeted retention initiatives should focus on the young-new recruits and allied health professionals. Particular attention should be dedicated to enhancing providers’ role satisfaction and sense of job security. Such initiatives are of pivotal importance to stabilize the workforce and ensure its longevity. PMID:23173905

Correlates of wife assault in Hong Kong Chinese families.

PubMed

Chan, Ko Ling

2004-04-01

The objective of this study was the risk factors of wife assault in Hong Kong Chinese families. The sample included 107 battered women from a refuge for battered women. Factor analysis revealed risk factors like dominance, stress, poor anger management, aggressive personality, conflict, lack of empathy, masculine gender role stress, sense of insecurity, relationship distress, and violent socialization. Correlation analysis indicated that dominance, spousal conflict, and sense of insecurity increase the likelihood of carrying out minor physical assault and using psychological aggression, while aggressive personality predicts severe physical assault and injury. The risk factors were explained in terms of traditional Chinese concepts of gender role expectations of men and women and face orientations. The present study provides some evidence relating to the risk factors of wife assault in Chinese families.

Endoscopic carpal tunnel release: a prospective analysis of factors associated with unsatisfactory results.

PubMed

Straub, T A

1999-04-01

The first 100 consecutive cases of endoscopic carpal tunnel release (ECTR) performed by the author were studied prospectively during 6 to 24 months follow-up. Various preoperative and postoperative factors were subjected to statistical analysis to determine possible associations with unsatisfactory results. Overall, 92% of hands had a satisfactory result from ECTR, although not all were rendered symptom-free. There were no significant complications. Preoperative factors associated with an increased likelihood of unsatisfactory results included hands with preoperative weakness, widened two-point discrimination, myofascial pain syndrome or fibromyalgia, involvement in litigation, multiple compressive neuropathies, or the presence of abnormal psychological factors. A trend to less satisfactory results was present in Workers' Compensation cases and patients with normal motor latencies on nerve conduction studies. Multiple postoperative factors correlated with unsatisfactory results.

The relationship between employment and veteran status, disability and gender from 2004-2011 Behavioral Risk Factor Surveillance System (BRFSS).

PubMed

Smith, Diane L

2014-01-01

In 2011, about 1.8 million or 8 percent of the 22.2 million veterans were women in the US. The unemployment rate for female veterans of the wars in Iraq and Afghanistan rose to 13.5%, above the 8.4% for non-veteran adult women. To examine data from the Behavioral Risk Factor Surveillance System (BRFSS), from 2004-2011 to determine the relationship between employment and veteran status, disability and gender. Chi square analysis was used to determine if significant differences existed between the employment rate of female veterans with disabilities and female veterans without disabilities, female non-veterans with disabilities and male veterans with disabilities. Binomial logistic regression analysis was used to determine how veteran status, disability and gender affected the likelihood of not being employed. Significant differences were found in employment rate between female veterans with disabilities and female veterans without disabilities, but not when compared to female non-veterans with disabilities or male veterans with disabilities. Disability was the strongest factor increasing the likelihood of not being employed, though veteran status and female gender were also predictive. Female veterans with disabilities experience low levels of employment. Policies and programs are needed to address the unique needs of these veterans.

Cosmology with the largest galaxy cluster surveys: going beyond Fisher matrix forecasts

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

Khedekar, Satej; Majumdar, Subhabrata, E-mail: satej@mpa-garching.mpg.de, E-mail: subha@tifr.res.in

2013-02-01

We make the first detailed MCMC likelihood study of cosmological constraints that are expected from some of the largest, ongoing and proposed, cluster surveys in different wave-bands and compare the estimates to the prevalent Fisher matrix forecasts. Mock catalogs of cluster counts expected from the surveys — eROSITA, WFXT, RCS2, DES and Planck, along with a mock dataset of follow-up mass calibrations are analyzed for this purpose. A fair agreement between MCMC and Fisher results is found only in the case of minimal models. However, for many cases, the marginalized constraints obtained from Fisher and MCMC methods can differ bymore » factors of 30-100%. The discrepancy can be alarmingly large for a time dependent dark energy equation of state, w(a); the Fisher methods are seen to under-estimate the constraints by as much as a factor of 4-5. Typically, Fisher estimates become more and more inappropriate as we move away from ΛCDM, to a constant-w dark energy to varying-w dark energy cosmologies. Fisher analysis, also, predicts incorrect parameter degeneracies. There are noticeable offsets in the likelihood contours obtained from Fisher methods that is caused due to an asymmetry in the posterior likelihood distribution as seen through a MCMC analysis. From the point of mass-calibration uncertainties, a high value of unknown scatter about the mean mass-observable relation, and its redshift dependence, is seen to have large degeneracies with the cosmological parameters σ{sub 8} and w(a) and can degrade the cosmological constraints considerably. We find that the addition of mass-calibrated cluster datasets can improve dark energy and σ{sub 8} constraints by factors of 2-3 from what can be obtained from CMB+SNe+BAO only . Finally, we show that a joint analysis of datasets of two (or more) different cluster surveys would significantly tighten cosmological constraints from using clusters only. Since, details of future cluster surveys are still being planned, we emphasize that optimal survey design must be done using MCMC analysis rather than Fisher forecasting.« less

Lifestyle factors and multimorbidity: a cross sectional study

PubMed Central

2014-01-01

Background Lifestyle factors have been associated mostly with individual chronic diseases. We investigated the relationship between lifestyle factors (individual and combined) and the co-occurrence of multiple chronic diseases. Methods Cross-sectional analysis of results from the Program of Research on the Evolution of a Cohort Investigating Health System Effects (PRECISE) in Quebec, Canada. Subjects aged 45 years and older. A randomly-selected cohort in the general population recruited by telephone. Multimorbidity (3 or more chronic diseases) was measured by a simple count of self-reported chronic diseases from a list of 14. Five lifestyle factors (LFs) were evaluated: 1) smoking habit, 2) alcohol consumption, 3) fruit and vegetable consumption, 4) physical activity, and 5) body mass index (BMI). Each LF was given a score of 1 (unhealthy) if recommended behavioural targets were not achieved and 0 otherwise. The combined effect of unhealthy LFs (ULFs) was evaluated using the total sum of scores. Results A total of 1,196 subjects were analyzed. Mean number of ULFs was 2.6 ± 1.1 SD. When ULFs were considered separately, there was an increased likelihood of multimorbidity with low or high BMI [Odd ratio (95% Confidence Interval): men, 1.96 (1.11-3.46); women, 2.57 (1.65-4.00)], and present or past smoker [men, 3.16 (1.74-5.73)]. When combined, in men, 4-5 ULFs increased the likelihood of multimorbidity [5.23 (1.70-16.1)]; in women, starting from a threshold of 2 ULFs [1.95 (1.05-3.62)], accumulating more ULFs progressively increased the likelihood of multimorbidity. Conclusions The present study provides support to the association of lifestyle factors and multimorbidity. PMID:24996220

A retrospective likelihood approach for efficient integration of multiple omics factors in case-control association studies.

PubMed

Balliu, Brunilda; Tsonaka, Roula; Boehringer, Stefan; Houwing-Duistermaat, Jeanine

2015-03-01

Integrative omics, the joint analysis of outcome and multiple types of omics data, such as genomics, epigenomics, and transcriptomics data, constitute a promising approach for powerful and biologically relevant association studies. These studies often employ a case-control design, and often include nonomics covariates, such as age and gender, that may modify the underlying omics risk factors. An open question is how to best integrate multiple omics and nonomics information to maximize statistical power in case-control studies that ascertain individuals based on the phenotype. Recent work on integrative omics have used prospective approaches, modeling case-control status conditional on omics, and nonomics risk factors. Compared to univariate approaches, jointly analyzing multiple risk factors with a prospective approach increases power in nonascertained cohorts. However, these prospective approaches often lose power in case-control studies. In this article, we propose a novel statistical method for integrating multiple omics and nonomics factors in case-control association studies. Our method is based on a retrospective likelihood function that models the joint distribution of omics and nonomics factors conditional on case-control status. The new method provides accurate control of Type I error rate and has increased efficiency over prospective approaches in both simulated and real data. © 2015 Wiley Periodicals, Inc.

Foreground effect on the J-factor estimation of ultra-faint dwarf spheroidal galaxies

NASA Astrophysics Data System (ADS)

Ichikawa, Koji; Horigome, Shun-ichi; Ishigaki, Miho N.; Matsumoto, Shigeki; Ibe, Masahiro; Sugai, Hajime; Hayashi, Kohei

2018-05-01

Dwarf spheroidal galaxies (dSphs) are promising targets for the gamma-ray dark matter (DM) search. In particular, DM annihilation signal is expected to be strong in some of the recently discovered nearby ultra-faint dSphs, which potentially give stringent constraints on the O(1) TeV WIMP DM. However, various non-negligible systematic uncertainties complicate the estimation of the astrophysical factors relevant for the DM search in these objects. Among them, the effects of foreground stars particularly attract attention because the contamination is unavoidable even for the future kinematical survey. In this article, we assess the effects of the foreground contamination on the astrophysical J-factor estimation by generating mock samples of stars in the four ultra-faint dSphs and using a model of future spectrographs. We investigate various data cuts to optimize the quality of the data and apply a likelihood analysis which takes member and foreground stellar distributions into account. We show that the foreground star contaminations in the signal region (the region of interest) and their statistical uncertainty can be estimated by interpolating the foreground star distribution in the control region where the foreground stars dominate the member stars. Such regions can be secured at future spectroscopic observations utilizing a multiple object spectrograph with a large field of view; e.g. the Prime Focus Spectrograph mounted on Subaru Telescope. The above estimation has several advantages: The data-driven estimation of the contamination makes the analysis of the astrophysical factor stable against the complicated foreground distribution. Besides, foreground contamination effect is considered in the likelihood analysis.

Near-exact distributions for the block equicorrelation and equivariance likelihood ratio test statistic

NASA Astrophysics Data System (ADS)

Coelho, Carlos A.; Marques, Filipe J.

2013-09-01

In this paper the authors combine the equicorrelation and equivariance test introduced by Wilks [13] with the likelihood ratio test (l.r.t.) for independence of groups of variables to obtain the l.r.t. of block equicorrelation and equivariance. This test or its single block version may find applications in many areas as in psychology, education, medicine, genetics and they are important "in many tests of multivariate analysis, e.g. in MANOVA, Profile Analysis, Growth Curve analysis, etc" [12, 9]. By decomposing the overall hypothesis into the hypotheses of independence of groups of variables and the hypothesis of equicorrelation and equivariance we are able to obtain the expressions for the overall l.r.t. statistic and its moments. From these we obtain a suitable factorization of the characteristic function (c.f.) of the logarithm of the l.r.t. statistic, which enables us to develop highly manageable and precise near-exact distributions for the test statistic.

MIXOR: a computer program for mixed-effects ordinal regression analysis.

PubMed

Hedeker, D; Gibbons, R D

1996-03-01

MIXOR provides maximum marginal likelihood estimates for mixed-effects ordinal probit, logistic, and complementary log-log regression models. These models can be used for analysis of dichotomous and ordinal outcomes from either a clustered or longitudinal design. For clustered data, the mixed-effects model assumes that data within clusters are dependent. The degree of dependency is jointly estimated with the usual model parameters, thus adjusting for dependence resulting from clustering of the data. Similarly, for longitudinal data, the mixed-effects approach can allow for individual-varying intercepts and slopes across time, and can estimate the degree to which these time-related effects vary in the population of individuals. MIXOR uses marginal maximum likelihood estimation, utilizing a Fisher-scoring solution. For the scoring solution, the Cholesky factor of the random-effects variance-covariance matrix is estimated, along with the effects of model covariates. Examples illustrating usage and features of MIXOR are provided.

Common Cause Case Study: An Estimated Probability of Four Solid Rocket Booster Hold-down Post Stud Hang-ups

NASA Technical Reports Server (NTRS)

Cross, Robert

2005-01-01

Until Solid Rocket Motor ignition, the Space Shuttle is mated to the Mobil Launch Platform in part via eight (8) Solid Rocket Booster (SRB) hold-down bolts. The bolts are fractured using redundant pyrotechnics, and are designed to drop through a hold-down post on the Mobile Launch Platform before the Space Shuttle begins movement. The Space Shuttle program has experienced numerous failures where a bolt has "hung-up." That is, it did not clear the hold-down post before liftoff and was caught by the SRBs. This places an additional structural load on the vehicle that was not included in the original certification requirements. The Space Shuttle is currently being certified to withstand the loads induced by up to three (3) of eight (8) SRB hold-down post studs experiencing a "hang-up." The results af loads analyses performed for four (4) stud-hang ups indicate that the internal vehicle loads exceed current structural certification limits at several locations. To determine the risk to the vehicle from four (4) stud hang-ups, the likelihood of the scenario occurring must first be evaluated. Prior to the analysis discussed in this paper, the likelihood of occurrence had been estimated assuming that the stud hang-ups were completely independent events. That is, it was assumed that no common causes or factors existed between the individual stud hang-up events. A review of the data associated with the hang-up events, showed that a common factor (timing skew) was present. This paper summarizes a revised likelihood evaluation performed for the four (4) stud hang-ups case considering that there are common factors associated with the stud hang-ups. The results show that explicitly (i.e. not using standard common cause methodologies such as beta factor or Multiple Greek Letter modeling) taking into account the common factor of timing skew results in an increase in the estimated likelihood of four (4) stud hang-ups of an order of magnitude over the independent failure case.

Common Cause Case Study: An Estimated Probability of Four Solid Rocket Booster Hold-Down Post Stud Hang-ups

NASA Technical Reports Server (NTRS)

Cross, Robert

2005-01-01

Until Solid Rocket Motor ignition, the Space Shuttle is mated to the Mobil Launch Platform in part via eight (8) Solid Rocket Booster (SRB) hold-down bolts. The bolts are fractured using redundant pyrotechnics, and are designed to drop through a hold-down post on the Mobile Launch Platform before the Space Shuttle begins movement. The Space Shuttle program has experienced numerous failures where a bolt has hung up. That is, it did not clear the hold-down post before liftoff and was caught by the SRBs. This places an additional structural load on the vehicle that was not included in the original certification requirements. The Space Shuttle is currently being certified to withstand the loads induced by up to three (3) of eight (8) SRB hold-down experiencing a "hang-up". The results of loads analyses performed for (4) stud hang-ups indicate that the internal vehicle loads exceed current structural certification limits at several locations. To determine the risk to the vehicle from four (4) stud hang-ups, the likelihood of the scenario occurring must first be evaluated. Prior to the analysis discussed in this paper, the likelihood of occurrence had been estimated assuming that the stud hang-ups were completely independent events. That is, it was assumed that no common causes or factors existed between the individual stud hang-up events. A review of the data associated with the hang-up events, showed that a common factor (timing skew) was present. This paper summarizes a revised likelihood evaluation performed for the four (4) stud hang-ups case considering that there are common factors associated with the stud hang-ups. The results show that explicitly (i.e. not using standard common cause methodologies such as beta factor or Multiple Greek Letter modeling) taking into account the common factor of timing skew results in an increase in the estimated likelihood of four (4) stud hang-ups of an order of magnitude over the independent failure case.

Geographic variation in cesarean delivery in the United States by payer.

PubMed

Henke, Rachel Mosher; Wier, Lauren M; Marder, William D; Friedman, Bernard S; Wong, Herbert S

2014-11-19

The rate of cesarean delivery in the United States is variable across geographic areas. The aims of this study are two-fold: (1) to determine whether the geographic variation in cesarean delivery rate is consistent for private insurance and Medicaid (2) to identify the patient, population, and market factors associated with cesarean rate and determine if these factors vary by payer. We used the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID) to measure the cesarean rate at the Core-Based Statistical Area (CBSA) level. We linked the hospitalization data to data from other national sources to measure population and market characteristics. We calculated unadjusted and risk-adjusted CBSA cesarean rates by payer. For the second aim, we estimated a hierarchical logistical model with the hospitalization as the unit of analysis to determine the factors associated with cesarean delivery. The average CBSA cesarean rate for women with private insurance was higher (18.9 percent) than for women with Medicaid (16.4 percent). The factors predicting cesarean rate were largely consistent across payers, with the following exceptions: women under age 18 had a greater likelihood of cesarean section if they had Medicaid but had a greater likelihood of vaginal birth if they had private insurance; Asian and Native American women with private insurance had a greater likelihood of cesarean section but Asian and Native American women with Medicaid had a greater likelihood of vaginal birth. The percent African American in the population predicted increased cesarean rates for private insurance only; the number of acute care beds per capita predicted increased cesarean rate for women with Medicaid but not women with private insurance. Further we found the number of obstetricians/gynecologists per capita predicted increased cesarean rate for women with private insurance only, and the number of midwives per capita predicted increased vaginal birth rate for women with private insurance only. Factors associated with geographic variation in cesarean delivery, a frequent and high-resource inpatient procedure, vary somewhat by payer. Using this information to identify areas for intervention is key to improving quality of care and reducing healthcare costs.

The Association between Environmental Factors and Scarlet Fever Incidence in Beijing Region: Using GIS and Spatial Regression Models

PubMed Central

Mahara, Gehendra; Wang, Chao; Yang, Kun; Chen, Sipeng; Guo, Jin; Gao, Qi; Wang, Wei; Wang, Quanyi; Guo, Xiuhua

2016-01-01

(1) Background: Evidence regarding scarlet fever and its relationship with meteorological, including air pollution factors, is not very available. This study aimed to examine the relationship between ambient air pollutants and meteorological factors with scarlet fever occurrence in Beijing, China. (2) Methods: A retrospective ecological study was carried out to distinguish the epidemic characteristics of scarlet fever incidence in Beijing districts from 2013 to 2014. Daily incidence and corresponding air pollutant and meteorological data were used to develop the model. Global Moran’s I statistic and Anselin’s local Moran’s I (LISA) were applied to detect the spatial autocorrelation (spatial dependency) and clusters of scarlet fever incidence. The spatial lag model (SLM) and spatial error model (SEM) including ordinary least squares (OLS) models were then applied to probe the association between scarlet fever incidence and meteorological including air pollution factors. (3) Results: Among the 5491 cases, more than half (62%) were male, and more than one-third (37.8%) were female, with the annual average incidence rate 14.64 per 100,000 population. Spatial autocorrelation analysis exhibited the existence of spatial dependence; therefore, we applied spatial regression models. After comparing the values of R-square, log-likelihood and the Akaike information criterion (AIC) among the three models, the OLS model (R2 = 0.0741, log likelihood = −1819.69, AIC = 3665.38), SLM (R2 = 0.0786, log likelihood = −1819.04, AIC = 3665.08) and SEM (R2 = 0.0743, log likelihood = −1819.67, AIC = 3665.36), identified that the spatial lag model (SLM) was best for model fit for the regression model. There was a positive significant association between nitrogen oxide (p = 0.027), rainfall (p = 0.036) and sunshine hour (p = 0.048), while the relative humidity (p = 0.034) had an adverse association with scarlet fever incidence in SLM. (4) Conclusions: Our findings indicated that meteorological, as well as air pollutant factors may increase the incidence of scarlet fever; these findings may help to guide scarlet fever control programs and targeting the intervention. PMID:27827946

The Association between Environmental Factors and Scarlet Fever Incidence in Beijing Region: Using GIS and Spatial Regression Models.

PubMed

Mahara, Gehendra; Wang, Chao; Yang, Kun; Chen, Sipeng; Guo, Jin; Gao, Qi; Wang, Wei; Wang, Quanyi; Guo, Xiuhua

2016-11-04

(1) Background: Evidence regarding scarlet fever and its relationship with meteorological, including air pollution factors, is not very available. This study aimed to examine the relationship between ambient air pollutants and meteorological factors with scarlet fever occurrence in Beijing, China. (2) Methods: A retrospective ecological study was carried out to distinguish the epidemic characteristics of scarlet fever incidence in Beijing districts from 2013 to 2014. Daily incidence and corresponding air pollutant and meteorological data were used to develop the model. Global Moran's I statistic and Anselin's local Moran's I (LISA) were applied to detect the spatial autocorrelation (spatial dependency) and clusters of scarlet fever incidence. The spatial lag model (SLM) and spatial error model (SEM) including ordinary least squares (OLS) models were then applied to probe the association between scarlet fever incidence and meteorological including air pollution factors. (3) Results: Among the 5491 cases, more than half (62%) were male, and more than one-third (37.8%) were female, with the annual average incidence rate 14.64 per 100,000 population. Spatial autocorrelation analysis exhibited the existence of spatial dependence; therefore, we applied spatial regression models. After comparing the values of R-square, log-likelihood and the Akaike information criterion (AIC) among the three models, the OLS model (R² = 0.0741, log likelihood = -1819.69, AIC = 3665.38), SLM (R² = 0.0786, log likelihood = -1819.04, AIC = 3665.08) and SEM (R² = 0.0743, log likelihood = -1819.67, AIC = 3665.36), identified that the spatial lag model (SLM) was best for model fit for the regression model. There was a positive significant association between nitrogen oxide ( p = 0.027), rainfall ( p = 0.036) and sunshine hour ( p = 0.048), while the relative humidity ( p = 0.034) had an adverse association with scarlet fever incidence in SLM. (4) Conclusions: Our findings indicated that meteorological, as well as air pollutant factors may increase the incidence of scarlet fever; these findings may help to guide scarlet fever control programs and targeting the intervention.

Smoking among American adolescents: a risk and protective factor analysis.

PubMed

Scal, Peter; Ireland, Marjorie; Borowsky, Iris Wagman

2003-04-01

Cigarette smoking remains a substantial threat to the current and future health of America's youth. The purpose of this study was to identify the risk and protective factors for cigarette smoking among US adolescents. Data from the National Longitudinal Study of Adolescent Health was used, comparing the responses of all non-smokers at Time 1 for their ability to predict the likelihood of smoking at Time 2, one year later. Data was stratified into four gender by grade group cohorts. Cross-cutting risk factors for smoking among all four cohorts were: using alcohol, marijuana, and other illicit drugs; violence involvement; having had sex; having friends who smoke and learning problems. Having a higher grade point average and family connectedness were protective across all cohorts. Other gender and grade group specific risk and protective factors were identified. The estimated probability of initiating smoking decreased by 19.2% to 54.1% both in situations of high and low risk as the number of protective factors present increased. Of the factors that predict or protect against smoking some are influential across all gender and grade group cohorts studied, while others are specific to gender and developmental stage. Prevention efforts that target both the reduction of risk factors and enhancement of protective factors at the individual, family, peer group and community are likely to reduce the likelihood of smoking initiation.

Estimating the variance for heterogeneity in arm-based network meta-analysis.

PubMed

Piepho, Hans-Peter; Madden, Laurence V; Roger, James; Payne, Roger; Williams, Emlyn R

2018-04-19

Network meta-analysis can be implemented by using arm-based or contrast-based models. Here we focus on arm-based models and fit them using generalized linear mixed model procedures. Full maximum likelihood (ML) estimation leads to biased trial-by-treatment interaction variance estimates for heterogeneity. Thus, our objective is to investigate alternative approaches to variance estimation that reduce bias compared with full ML. Specifically, we use penalized quasi-likelihood/pseudo-likelihood and hierarchical (h) likelihood approaches. In addition, we consider a novel model modification that yields estimators akin to the residual maximum likelihood estimator for linear mixed models. The proposed methods are compared by simulation, and 2 real datasets are used for illustration. Simulations show that penalized quasi-likelihood/pseudo-likelihood and h-likelihood reduce bias and yield satisfactory coverage rates. Sum-to-zero restriction and baseline contrasts for random trial-by-treatment interaction effects, as well as a residual ML-like adjustment, also reduce bias compared with an unconstrained model when ML is used, but coverage rates are not quite as good. Penalized quasi-likelihood/pseudo-likelihood and h-likelihood are therefore recommended. Copyright © 2018 John Wiley & Sons, Ltd.

Parkinson's disease: a population-based investigation of life satisfaction and employment.

PubMed

Gustafsson, Helena; Nordström, Peter; Stråhle, Stefan; Nordström, Anna

2015-01-01

To investigate relationships between individuals' socioeconomic situations and quality of life in working-aged subjects with Parkinson's disease. A population-based cohort comprising 1,432 people with Parkinson's disease and 1,135 matched controls, who responded to a questionnaire. Logistic regression analysis was performed to identify factors associated with life satisfaction and likelihood of employment. In multivariate analyses, Parkinson's disease was associated with an increased risk of dissatisfaction with life (odds ratio (OR) = 5.4, 95% confidence interval (95% CI) = 4.2-7.1) and reduced likelihood of employment (OR = 0.30, 95% CI = 0.25-0.37). Employers' support was associated with greater likelihood of employment (p < 0.001). Twenty-four percent of people with Parkinson's disease for ≥ 10 years remained employed and 6% worked full-time. People with Parkinson's disease also more frequently experienced work demands that exceeded their capacity; this factor and unemployment independently correlated with greater risk of dissatisfaction with life (both p < 0.05). People with Parkinson's disease have an increased risk of dissatisfaction with life. Employment situation is important for general life satisfaction among working-aged individuals. People with Parkinson's disease appear to find it difficult to meet the challenge of achieving a balanced employment situation.

Characteristics of cyclist crashes in Italy using latent class analysis and association rule mining

PubMed Central

De Angelis, Marco; Marín Puchades, Víctor; Fraboni, Federico; Pietrantoni, Luca

2017-01-01

The factors associated with severity of the bicycle crashes may differ across different bicycle crash patterns. Therefore, it is important to identify distinct bicycle crash patterns with homogeneous attributes. The current study aimed at identifying subgroups of bicycle crashes in Italy and analyzing separately the different bicycle crash types. The present study focused on bicycle crashes that occurred in Italy during the period between 2011 and 2013. We analyzed categorical indicators corresponding to the characteristics of infrastructure (road type, road signage, and location type), road user (i.e., opponent vehicle and cyclist’s maneuver, type of collision, age and gender of the cyclist), vehicle (type of opponent vehicle), and the environmental and time period variables (time of the day, day of the week, season, pavement condition, and weather). To identify homogenous subgroups of bicycle crashes, we used latent class analysis. Using latent class analysis, the bicycle crash data set was segmented into 19 classes, which represents 19 different bicycle crash types. Logistic regression analysis was used to identify the association between class membership and severity of the bicycle crashes. Finally, association rules were conducted for each of the latent classes to uncover the factors associated with an increased likelihood of severity. Association rules highlighted different crash characteristics associated with an increased likelihood of severity for each of the 19 bicycle crash types. PMID:28158296

Support for Relatives Bereaved by Psychiatric Patient Suicide: National Confidential Inquiry Into Suicide and Homicide Findings.

PubMed

Pitman, Alexandra L; Hunt, Isabelle M; McDonnell, Sharon J; Appleby, Louis; Kapur, Navneet

2017-04-01

International suicide prevention strategies recommend providing support to families bereaved by suicide. The study objectives were to measure the proportion of cases in which psychiatric professionals contact next of kin after a patient's suicide and to investigate whether specific, potentially stigmatizing patient characteristics influence whether the family is contacted. Annual survey data from England and Wales (2003-2012) were used to identify 11,572 suicide cases among psychiatric patients. Multivariate regression analysis was used to describe the association between specific covariates (chosen on the basis of clinical judgment and the published literature) and the probability that psychiatric staff would contact bereaved relatives of the deceased. Relatives were not contacted after the death in 33% of cases. Contrary to the hypothesis, a violent method of suicide was independently associated with greater likelihood of contact with relatives (adjusted odds ratio=1.67). Four patient factors (forensic history, unemployment, and primary diagnosis of alcohol or drug dependence or misuse) were independently associated with less likelihood of contact with relatives. Patients' race-ethnicity and recent alcohol or drug misuse were not associated with contact with relatives. Four stigmatizing patient-related factors reduced the likelihood of contacting next of kin after patient suicide, suggesting inequitable access to support after a potentially traumatic bereavement. Given the association of suicide bereavement with suicide attempt, and the possibility of relatives' shared risk factors for suicide, British psychiatric services should provide more support to relatives after patient suicide.

Relationship between two indicators of coronary risk estimated by the Framingham Risk Score and the number of metabolic syndrome components in Japanese male manufacturing workers.

PubMed

Kawada, Tomoyuki; Otsuka, Toshiaki; Inagaki, Hirofumi; Wakayama, Yoko; Li, Qing; Katsumata, Masao

2009-10-01

The Framingham Risk Score (FRS) has frequently been used in the United States to predict the 10-year risk of coronary heart disease (CHD). Components of the metabolic syndrome and several lifestyle factors have also been evaluated to estimate the risk of CHD. To determine the relationship between the FRS and components of metabolic syndrome as coronary risk indicators, the authors conducted a cross-sectional study of 2,619 Japanese male workers, ranging in age from 40 to 64 years, at a single workplace. Although the estimation by the FRS and metabolic syndrome involved some different factors, significant association of the risk estimated by the 2 methods was observed. When logistic regression analysis was conducted with adjustment for several lifestyle factors, the FRS and serum insulin were found to be significantly associated with the risk of likelihood of metabolic syndrome. The odds ratios and 95% confidence intervals of FRS by per standard deviation increment and serum insulin by increasing 1 microIU/mL for the prediction of metabolic syndrome were 2.50 (2.17-2.88) and 1.24 (1.20-1.27), respectively. A preventive effect of abstaining from drinking every day and eating breakfast almost daily against the likelihood of metabolic syndrome was also observed. In conclusion, the FRS and insulin were found to be significantly associated with the risk of likelihood of metabolic syndrome, even after controlling for weight change.

Effect of formal and informal likelihood functions on uncertainty assessment in a single event rainfall-runoff model

NASA Astrophysics Data System (ADS)

Nourali, Mahrouz; Ghahraman, Bijan; Pourreza-Bilondi, Mohsen; Davary, Kamran

2016-09-01

In the present study, DREAM(ZS), Differential Evolution Adaptive Metropolis combined with both formal and informal likelihood functions, is used to investigate uncertainty of parameters of the HEC-HMS model in Tamar watershed, Golestan province, Iran. In order to assess the uncertainty of 24 parameters used in HMS, three flood events were used to calibrate and one flood event was used to validate the posterior distributions. Moreover, performance of seven different likelihood functions (L1-L7) was assessed by means of DREAM(ZS)approach. Four likelihood functions, L1-L4, Nash-Sutcliffe (NS) efficiency, Normalized absolute error (NAE), Index of agreement (IOA), and Chiew-McMahon efficiency (CM), is considered as informal, whereas remaining (L5-L7) is represented in formal category. L5 focuses on the relationship between the traditional least squares fitting and the Bayesian inference, and L6, is a hetereoscedastic maximum likelihood error (HMLE) estimator. Finally, in likelihood function L7, serial dependence of residual errors is accounted using a first-order autoregressive (AR) model of the residuals. According to the results, sensitivities of the parameters strongly depend on the likelihood function, and vary for different likelihood functions. Most of the parameters were better defined by formal likelihood functions L5 and L7 and showed a high sensitivity to model performance. Posterior cumulative distributions corresponding to the informal likelihood functions L1, L2, L3, L4 and the formal likelihood function L6 are approximately the same for most of the sub-basins, and these likelihood functions depict almost a similar effect on sensitivity of parameters. 95% total prediction uncertainty bounds bracketed most of the observed data. Considering all the statistical indicators and criteria of uncertainty assessment, including RMSE, KGE, NS, P-factor and R-factor, results showed that DREAM(ZS) algorithm performed better under formal likelihood functions L5 and L7, but likelihood function L5 may result in biased and unreliable estimation of parameters due to violation of the residualerror assumptions. Thus, likelihood function L7 provides posterior distribution of model parameters credibly and therefore can be employed for further applications.

A Structural Equation Model for the School Reinforcement Survey Schedule: Italian and American Early Adolescents

ERIC Educational Resources Information Center

Holmes, George R.; Galeazzi, Aldo; Franceschina, Emilio; McNulty, George F.; Forand, Angela Q.; Stader, Sandra R.; Myers, deRosset, Jr.; Wright, Harry H.

2004-01-01

The School Reinforcement Survey Schedule (SRSS) was administered to 2,828 boys and girls in middle schools in the United States and an Italian translation was administered to 342 boys and girls in middle schools in Northern Italy. An exploratory factor analysis using half the American data set was performed using maximum likelihood estimation with…

Sociodemographic, lifestyle and health determinants of suicidal behaviour in Malaysia.

PubMed

Cheah, Yong Kang; Azahadi, Mohd; Phang, Siew Nooi; Abd Manaf, Noor Hazilah

2018-03-01

Suicide has become a serious matter in both developed and developing countries. The objective of the present study is to examine the factors affecting suicidal behaviour among adults in Malaysia. A nationally representative data which consists of 10,141 respondents is used for analysis. A trivariate probit model is utilised to identify the probability of having suicide ideation, suicide plan and suicide attempt. Results of the regression analysis show that to ensure unbiased estimates, a trivariate probit model should be used instead of three separate probit models. The determining factors of suicidal behaviour are income, age, gender, ethnicity, education, marital status, self-rated health and being diagnosed with diabetes and hypercholesterolemia. The likelihood of adopting suicidal behaviour is lower among higher income earners and older individuals. Being male and married significantly reduce the propensity to engage in suicidal behaviour. Of all the ethnic groups, Indian/others displays the highest likelihood of adopting suicidal behaviour. There is a positive relationship between poor health condition and suicide. Policies targeted at individuals who are likely to adopt suicidal behaviour may be effective in lowering the prevalence of suicide. Copyright © 2018 Elsevier B.V. All rights reserved.

Profile-Likelihood Approach for Estimating Generalized Linear Mixed Models with Factor Structures

ERIC Educational Resources Information Center

Jeon, Minjeong; Rabe-Hesketh, Sophia

2012-01-01

In this article, the authors suggest a profile-likelihood approach for estimating complex models by maximum likelihood (ML) using standard software and minimal programming. The method works whenever setting some of the parameters of the model to known constants turns the model into a standard model. An important class of models that can be…

Cycles till failure of silver-zinc cells with completing failures modes: Preliminary data analysis

NASA Technical Reports Server (NTRS)

Sidik, S. M.; Leibecki, H. F.; Bozek, J. M.

1980-01-01

One hundred and twenty nine cells were run through charge-discharge cycles until failure. The experiment design was a variant of a central composite factorial in five factors. Preliminary data analysis consisted of response surface estimation of life. Batteries fail under two basic modes; a low voltage condition and an internal shorting condition. A competing failure modes analysis using maximum likelihood estimation for the extreme value life distribution was performed. Extensive diagnostics such as residual plotting and probability plotting were employed to verify data quality and choice of model.

Analysis of case-only studies accounting for genotyping error.

PubMed

Cheng, K F

2007-03-01

The case-only design provides one approach to assess possible interactions between genetic and environmental factors. It has been shown that if these factors are conditionally independent, then a case-only analysis is not only valid but also very efficient. However, a drawback of the case-only approach is that its conclusions may be biased by genotyping errors. In this paper, our main aim is to propose a method for analysis of case-only studies when these errors occur. We show that the bias can be adjusted through the use of internal validation data, which are obtained by genotyping some sampled individuals twice. Our analysis is based on a simple and yet highly efficient conditional likelihood approach. Simulation studies considered in this paper confirm that the new method has acceptable performance under genotyping errors.

Medication monitoring attitudes and perceived determinants to offering medication adherence advice to older hypertensive adults: a factorial survey of community pharmacy interns.

PubMed

Dillon, Paul; Smith, Susan M; Gallagher, Paul; Cousins, Gráinne

2018-06-13

Community pharmacy is an ideal setting to monitor medication adherence, however, barriers to pharmacist-led interventions exist. Preparing future pharmacists for enhanced roles may overcome such barriers. Our objective was to identify medication monitoring attitudes and contextual factors that influence adherence monitoring by pharmacy interns to inform educational activities on medication adherence. An online factorial survey of all pharmacy interns (N = 123) in the Republic of Ireland, completing advanced community pharmacy experiential learning in May 2016 was undertaken to evaluate attitudes to medication monitoring and to identify respondent characteristics and contextual factors which influence adherence monitoring of older hypertensive adults during repeat dispensing. The medication monitoring attitude measure (MMAM) was used to evaluate interns' attitudes, and factorial vignette analysis was performed to identify factors influencing behavioural intention to offer adherence advice. There were 121 completed online surveys. Half of interns reported they felt uncomfortable and confrontational discussing adherence with patients. In factorial vignette analysis, higher medication monitoring attitudes resulted in higher likelihood to offer adherence advice; experiential-learning characteristics such as pharmacy ownership-type (nonchain store) and contextual factors including patients being treated for longer and time-pressures had a significant negative influence on pharmacy interns' likelihood to offer adherence advice. Medication monitoring attitudes and contextual factors influenced responses to offer adherence advice in hypothetical scenarios. Ensuring pharmacy students are educated on patterns of adherence and appropriate skills to address nonadherence, and engage in structured programmes to facilitate patient interactions during experiential learning, may improve medication monitoring attitudes and adherence monitoring. © 2018 Royal Pharmaceutical Society.

Analyzing seasonal patterns of wildfire exposure factors in Sardinia, Italy.

PubMed

Salis, Michele; Ager, Alan A; Alcasena, Fermin J; Arca, Bachisio; Finney, Mark A; Pellizzaro, Grazia; Spano, Donatella

2015-01-01

In this paper, we applied landscape scale wildfire simulation modeling to explore the spatiotemporal patterns of wildfire likelihood and intensity in the island of Sardinia (Italy). We also performed wildfire exposure analysis for selected highly valued resources on the island to identify areas characterized by high risk. We observed substantial variation in burn probability, fire size, and flame length among time periods within the fire season, which starts in early June and ends in late September. Peak burn probability and flame length were observed in late July. We found that patterns of wildfire likelihood and intensity were mainly related to spatiotemporal variation in ignition locations, fuel moisture, and wind vectors. Our modeling approach allowed consideration of historical patterns of winds, ignition locations, and live and dead fuel moisture on fire exposure factors. The methodology proposed can be useful for analyzing potential wildfire risk and effects at landscape scale, evaluating historical changes and future trends in wildfire exposure, as well as for addressing and informing fuel management and risk mitigation issues.

Avoiding overstating the strength of forensic evidence: Shrunk likelihood ratios/Bayes factors.

PubMed

Morrison, Geoffrey Stewart; Poh, Norman

2018-05-01

When strength of forensic evidence is quantified using sample data and statistical models, a concern may be raised as to whether the output of a model overestimates the strength of evidence. This is particularly the case when the amount of sample data is small, and hence sampling variability is high. This concern is related to concern about precision. This paper describes, explores, and tests three procedures which shrink the value of the likelihood ratio or Bayes factor toward the neutral value of one. The procedures are: (1) a Bayesian procedure with uninformative priors, (2) use of empirical lower and upper bounds (ELUB), and (3) a novel form of regularized logistic regression. As a benchmark, they are compared with linear discriminant analysis, and in some instances with non-regularized logistic regression. The behaviours of the procedures are explored using Monte Carlo simulated data, and tested on real data from comparisons of voice recordings, face images, and glass fragments. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Analysis of factors associated with traffic accidents of cyclists attended in Brazilian state capitals.

PubMed

Sousa, Carlos Augusto Moreira de; Bahia, Camila Alves; Constantino, Patrícia

2016-12-01

Brazil has the sixth largest bicycles fleet in the world and bicycle is the most used individual transport vehicle in the country. Few studies address the issue of cyclists' accidents and factors that contribute to or prevent this event. VIVA is a cross-sectional survey and is part of the Violence and Accidents Surveillance System, Brazilian Ministry of Health. We used complex sampling and subsequent data review through multivariate logistic regression and calculation of the respective odds ratios. Odds ratios showed greater likelihood of cyclists' accidents in males, people with less schooling and living in urban and periurban areas. People who were not using the bike to go to work were more likely to suffer an accident. The profile found in this study corroborates findings of other studies. They claim that the coexistence of cyclists and other means of transportation in the same urban space increases the likelihood of accidents. The construction of bicycle-exclusive spaces and educational campaigns are required.

Towards a brief definition of burnout syndrome by subtypes: Development of the "Burnout Clinical Subtypes Questionnaire" (BCSQ-12)

PubMed Central

2011-01-01

Background Burnout has traditionally been described by means of the dimensions of exhaustion, cynicism and lack of eficacy from the "Maslach Burnout Inventory-General Survey" (MBI-GS). The "Burnout Clinical Subtype Questionnaire" (BCSQ-12), comprising the dimensions of overload, lack of development and neglect, is proposed as a brief means of identifying the different ways this disorder is manifested. The aim of the study is to test the construct and criterial validity of the BCSQ-12. Method A cross-sectional design was used on a multi-occupational sample of randomly selected university employees (n = 826). An exploratory factor analysis (EFA) was performed on half of the sample using the maximum likelihood (ML) method with varimax orthogonal rotation, while confirmatory factor analysis (CFA) was performed on the other half by means of the ML method. ROC curve analysis was preformed in order to assess the discriminatory capacity of BCSQ-12 when compared to MBI-GS. Cut-off points were proposed for the BCSQ-12 that optimized sensitivity and specificity. Multivariate binary logistic regression models were used to estimate effect size as an odds ratio (OR) adjusted for sociodemographic and occupational variables. Contrasts for sex and occupation were made using Mann-Whitney U and Kruskall-Wallis tests on the dimensions of both models. Results EFA offered a solution containing 3 factors with eigenvalues > 1, explaining 73.22% of variance. CFA presented the following indices: χ2 = 112.04 (p < 0.001), χ2/gl = 2.44, GFI = 0.958, AGFI = 0.929, RMSEA = 0.059, SRMR = 0.057, NFI = 0.958, NNFI = 0.963, IFI = 0.975, CFI = 0.974. The area under the ROC curve for 'overload' with respect to the 'exhaustion' was = 0.75 (95% CI = 0.71-0.79); it was = 0.80 (95% CI = 0.76-0.86) for 'lack of development' with respect to 'cynicism' and = 0.74 (95% CI = 0.70-0.78) for 'neglect' with respect to 'inefficacy'. The presence of 'overload' increased the likelihood of suffering from 'exhaustion' (OR = 5.25; 95% IC = 3.62-7.60); 'lack of development' increased the likelihood from 'cynicism' (OR = 6.77; 95% CI = 4.79-9.57); 'neglect' increased the likelihood from 'inefficacy' (OR = 5.21; 95% CI = 3.57-7.60). No differences were found with regard to sex, but there were differences depending on occupation. Conclusions Our results support the validity of the definition of burnout proposed in the BSCQ-12 through the brief differentiation of clinical subtypes. PMID:21933381

Automation and Evaluation of the SOWH Test with SOWHAT.

PubMed

Church, Samuel H; Ryan, Joseph F; Dunn, Casey W

2015-11-01

The Swofford-Olsen-Waddell-Hillis (SOWH) test evaluates statistical support for incongruent phylogenetic topologies. It is commonly applied to determine if the maximum likelihood tree in a phylogenetic analysis is significantly different than an alternative hypothesis. The SOWH test compares the observed difference in log-likelihood between two topologies to a null distribution of differences in log-likelihood generated by parametric resampling. The test is a well-established phylogenetic method for topology testing, but it is sensitive to model misspecification, it is computationally burdensome to perform, and its implementation requires the investigator to make several decisions that each have the potential to affect the outcome of the test. We analyzed the effects of multiple factors using seven data sets to which the SOWH test was previously applied. These factors include a number of sample replicates, likelihood software, the introduction of gaps to simulated data, the use of distinct models of evolution for data simulation and likelihood inference, and a suggested test correction wherein an unresolved "zero-constrained" tree is used to simulate sequence data. To facilitate these analyses and future applications of the SOWH test, we wrote SOWHAT, a program that automates the SOWH test. We find that inadequate bootstrap sampling can change the outcome of the SOWH test. The results also show that using a zero-constrained tree for data simulation can result in a wider null distribution and higher p-values, but does not change the outcome of the SOWH test for most of the data sets tested here. These results will help others implement and evaluate the SOWH test and allow us to provide recommendations for future applications of the SOWH test. SOWHAT is available for download from https://github.com/josephryan/SOWHAT. © The Author(s) 2015. Published by Oxford University Press, on behalf of the Society of Systematic Biologists.

Factors That Impact Registered Nurses' Decisions to Continue Providing Care to Older Adults

ERIC Educational Resources Information Center

Bosfield, Saundra

2013-01-01

The purpose of this study was to investigate if there is a significant difference in the following: (a) nurses' likelihood to remain in geriatrics between age groups (those over 40 years of age and those under 40 years of age); (b) nurses' likelihood to remain in geriatrics and personality traits; (c) nurses' likelihood to remain in geriatrics…

Doping Attitudes and Covariates of Potential Doping Behaviour in High-Level Team-Sport Athletes; Gender Specific Analysis.

PubMed

Sekulic, Damir; Tahiraj, Enver; Zvan, Milan; Zenic, Natasa; Uljevic, Ognjen; Lesnik, Blaz

2016-12-01

Team sports are rarely studied with regard to doping behaviour and doping-related factors regardless of their global popularity. This study aimed to investigate doping factors and covariates of potential doping behaviour in high-level team-sport athletes. The subjects were 457 high-performing, national- and international-level athletes (21.9 ± 3.4 years of age; 179 females) involved in volleyball (n = 77), soccer (n = 163), basketball (n = 114) and handball (n = 103). Previously validated self-administered questionnaires aimed at evidencing sport factors, doping-related factors, knowledge on sport nutrition and doping, and attitudes to performance enhancement were used. The results indicated a higher doping likelihood in male athletes, with a significant gender difference for basketball and handball. In males, a higher doping likelihood is found for athletes who had achieved better results at junior-age level, those who regularly consume dietary supplements, and who perceive their sport as being contaminated by doping. A higher sport achievement at senior-age level is protective against potential doping behaviour in males. In females, a higher likelihood of doping is evidenced in those athletes involved in binge drinking, while a lower tendency for doping is evidenced in female athletes who possess better knowledge on sport nutrition. Knowledge about doping is very low and thus education about doping is urgently needed. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in females. Future studies should consider other approaches and theories, such as theory of planned behaviour and/or social-cognitive theory, in studying the problem of doping behaviour in team-sports.

Dimensionality of military job satisfaction items: an exploratory factor analysis of data from the spring 1996 Sample Survey of Military Personnel.

PubMed

Schumm, Walter R; Gade, Paul A; Bell, D Bruce

2003-06-01

The Sample Survey of Military Personnel in the spring of 1996 asked detailed questions of Army personnel about job satisfaction. Maximum likelihood factor analysis yielded four factors: satisfaction with supervision, with job environment, with the duty specifically, and with opportunity for development, factors similar to those used in Smith's Job Descriptive Index, 1992. Scales developed from these factors showed acceptable internal consistency reliability and correlated as expected with measures of satisfaction with Army life, retention, morale, combat preparedness, and overall job satisfaction. Some divergent validity was established with measures of personal/family stress and with previous job stress. Demographic data suggested that soldiers with higher education found more satisfying job opportunities while those with higher rank, more years of service, and higher age reported greater satisfaction with job fulfillment, perhaps a consequence of selection effects.

What affects public acceptance of recycled and desalinated water?

PubMed Central

Dolnicar, Sara; Hurlimann, Anna; Grün, Bettina

2011-01-01

This paper identifies factors that are associated with higher levels of public acceptance for recycled and desalinated water. For the first time, a wide range of hypothesized factors, both of socio-demographic and psychographic nature, are included simultaneously. The key results, based on a survey study of about 3000 respondents are that: (1) drivers of the stated likelihood of using desalinated water differ somewhat from drivers of the stated likelihood of using recycled water; (2) positive perceptions of, and knowledge about, the respective water source are key drivers for the stated likelihood of usage; and (3) awareness of water scarcity, as well as prior experience with using water from alternative sources, increases the stated likelihood of use. Practical recommendations for public policy makers, such as key messages to be communicated to the public, are derived. PMID:20950834

Analysis of threats to research validity introduced by audio recording clinic visits: Selection bias, Hawthorne effect, both, or neither?

PubMed Central

Henry, Stephen G.; Jerant, Anthony; Iosif, Ana-Maria; Feldman, Mitchell D.; Cipri, Camille; Kravitz, Richard L.

2015-01-01

Objective To identify factors associated with participant consent to record visits; to estimate effects of recording on patient-clinician interactions Methods Secondary analysis of data from a randomized trial studying communication about depression; participants were asked for optional consent to audio record study visits. Multiple logistic regression was used to model likelihood of patient and clinician consent. Multivariable regression and propensity score analyses were used to estimate effects of audio recording on 6 dependent variables: discussion of depressive symptoms, preventive health, and depression diagnosis; depression treatment recommendations; visit length; visit difficulty. Results Of 867 visits involving 135 primary care clinicians, 39% were recorded. For clinicians, only working in academic settings (P=0.003) and having worked longer at their current practice (P=0.02) were associated with increased likelihood of consent. For patients, white race (P=0.002) and diabetes (P=0.03) were associated with increased likelihood of consent. Neither multivariable regression nor propensity score analyses revealed any significant effects of recording on the variables examined. Conclusion Few clinician or patient characteristics were significantly associated with consent. Audio recording had no significant effect on any dependent variables. Practice Implications Benefits of recording clinic visits likely outweigh the risks of bias in this setting. PMID:25837372

When Can Categorical Variables Be Treated as Continuous? A Comparison of Robust Continuous and Categorical SEM Estimation Methods under Suboptimal Conditions

ERIC Educational Resources Information Center

Rhemtulla, Mijke; Brosseau-Liard, Patricia E.; Savalei, Victoria

2012-01-01

A simulation study compared the performance of robust normal theory maximum likelihood (ML) and robust categorical least squares (cat-LS) methodology for estimating confirmatory factor analysis models with ordinal variables. Data were generated from 2 models with 2-7 categories, 4 sample sizes, 2 latent distributions, and 5 patterns of category…

Religiosity profiles of American youth in relation to substance use, violence, and delinquency.

PubMed

Salas-Wright, Christopher P; Vaughn, Michael G; Hodge, David R; Perron, Brian E

2012-12-01

Relatively little is known in terms of the relationship between religiosity profiles and adolescents' involvement in substance use, violence, and delinquency. Using a diverse sample of 17,705 (49 % female) adolescents from the 2008 National Survey on Drug Use and Health, latent profile analysis and multinomial regression are employed to examine the relationships between latent religiosity classes and substance use, violence, and delinquency. Results revealed a five class solution. Classes were identified as religiously disengaged (10.76 %), religiously infrequent (23.59 %), privately religious (6.55 %), religious regulars (40.85 %), and religiously devoted (18.25 %). Membership in the religiously devoted class was associated with the decreased likelihood of participation in a variety of substance use behaviors as well as decreases in the likelihood of fighting and theft. To a lesser extent, membership in the religious regulars class was also associated with the decreased likelihood of substance use and fighting. However, membership in the religiously infrequent and privately religious classes was only associated with the decreased likelihood of marijuana use. Findings suggest that private religiosity alone does not serve to buffer youth effectively against involvement in problem behavior, but rather that it is the combination of intrinsic and extrinsic adolescent religiosity factors that is associated with participation in fewer problem behaviors.

Use of cultural consensus analysis to evaluate expert feedback of median safety.

PubMed

Kim, Tae-Gyu; Donnell, Eric T; Lee, Dongmin

2008-07-01

Cultural consensus analysis is a statistical method that can be used to assess participant responses to survey questions. The technique concurrently estimates the knowledge of each survey participant and estimates the culturally correct answer to each question asked, based on the existence of consensus among survey participants. The main objectives of this paper are to present the cultural consensus methodology and apply it to a set of median design and safety survey data that were collected using the Delphi method. A total of 21 Delphi survey participants were asked to answer research questions related to cross-median crashes. It was found that the Delphi panel had agreeable opinions with respect to the association of average daily traffic (ADT) and heavy vehicle percentage combination on the risk of cross-median crashes; relative importance of additional factors, other than ADT, median width, and crash history that may contribute to cross-median crashes; and, the relative importance of geometric factors that may be associated with the likelihood of cross-median crashes. Therefore, the findings from the cultural consensus analysis indicate that the expert panel selected to participate in the Delphi survey shared a common knowledge pool relative to the association between median design and safety. There were, however, diverse opinions regarding median barrier type and its preferred placement location. The panel showed a higher level of knowledge on the relative importance regarding the association of geometric factors on cross-median crashes likelihood than on other issues considered. The results of the cultural consensus analysis of the present median design and safety survey data could be used to design a focused field study of median safety.

Does your web site draw new patients?

PubMed

Wallin, Wendy S

2009-11-01

The absence of scientific data forces orthodontists to guess at how best to design Internet sites that persuade prospective patients to call for appointments. This study was conducted to identify the Web-site factors that lead prospective patients to make appointments or, conversely, to reject a practice. Ten participants actively looking online for an orthodontist were recruited to participate. They reviewed 64 orthodontic Web sites in their geographic areas and rated their likelihood of calling each practice for an appointment. The sessions were videotaped. Analysis of participant comments, navigation patterns, and ratings suggested 25 distinguishing factors. Statistical analysis showed 10 Web-site characteristics that predict the success of an orthodontic Web site in attracting new patients.

Risk factors for father-daughter incest: data from an anonymous computerized survey.

PubMed

Stroebel, Sandra S; Kuo, Shih-Ya; O'Keefe, Stephen L; Beard, Keith W; Swindell, Sam; Kommor, Martin J

2013-12-01

Retrospective data from 2,034 female participants, provided anonymously using a computer-assisted self-interview, were used to identify risk factors for father-daughter incest (FDI). A total of 51 participants had reported having experienced FDI. The risk factors identified within the nuclear family by the multiple logistic regression analysis included the following: (a) Having parents whose relationship included verbal or physical fighting or brutality increased the likelihood of FDI by approximately 5 times; (b) families accepting father-daughter nudity as measured by a scale with values ranging from 0 to 4 increased the likelihood of FDI by approximately 2 times for each unit value increase of 1 above 0; (c) demonstrating maternal affection protected against FDI. The likelihood of being a victim of FDI was highest if the participant's mother never kissed or hugged her; it decreased by 0.44 for a 1-unit increase in affection and by 0.19 times for a 2-unit increase; and (d) being in homes headed by single-parent mothers or where divorce or death of the father had resulted in a man other than the biological father living in the home increased the risk of FDI by approximately 3.2 times. The results were consistent with the idea that FDI in many families was the cumulative result of a circular pattern of interactions, a finding that has implications for treatment of the perpetrator, the victim, and the families. The data also suggested it may be possible to design an information program for parents that will result in reducing the risk of FDI in families implementing the program's recommendations.

Search for supersymmetry in 8 TeV proton-proton collision events with bottom-quark jets and missing transverse energy

NASA Astrophysics Data System (ADS)

Kreis, Benjamin

In the absence of meaningful federal action, many states have adopted clean energy policies aimed at reducing carbon emissions. Among these policies is the energy efficiency resource standard (EERS), adopted by 33 states mostly in the last decade, which sets an energy consumption reduction target for some or all regulated utilities within a state. My paper examines what factors affect a state's likelihood of adopting an EERS, and whether those factors are different for EERS policies compared with other clean energy policies. The energy policy literature features many studies of clean energy policy adoption, but none have focused specifically on EERS adoption. I theorized that energy efficiency potential being relatively homogeneously distributed across states (compared to renewable energy potential) and efficiency's relative inexpensiveness as a resource would result in a unique set of factors being associated with the likelihood of EERS adoption. Specifically, I expected that three internal determinants--the presence of utility rate decoupling in a state, a state's political ideology, and the state's average retail price of residential electricity--affect a state's likelihood of adopting an EERS. To test these hypotheses, I estimated several multiple regression models using an event history analysis approach and found that citizen liberalism, level of electricity consumption, and a time counter variable were all statistically significant and positive predictors of state adoption of an EERS, all else equal. I found no association between decoupling or electricity price and EERS adoption, though in the case of the former that may be a result of insufficient data.

A Study of Relationships among Technical, Tactical, Physical Parameters and Final Outcomes in Elite Soccer Matches as Analyzed by a Semiautomatic Video Tracking System.

PubMed

Filetti, Cristoforo; Ruscello, Bruno; D'Ottavio, Stefano; Fanelli, Vito

2017-06-01

The performance of a soccer team depends on many factors such as decision-making, cognitive and physical skills, and dynamic ever-changing space-time interactions between teammate and opponents in relation to the ball. Seventy ( n = 70) matches of the Italian SERIE A season 2013-2014 were investigated to analyze the mean performance of 360 players in terms of physical (physical efficiency index; PEI) and technical-tactical (technical efficiency index; TEI) standpoints. Using a semiautomatic video analysis system that has incorporated new parameters able to measure technical-tactical and physical efficiency (Patent IB2010/002593, 2011-ISA), the correlation between these new variables and how much it relates to the likelihood of winning were verified. Correlations between TEI and PEI were significant ( n = 140, r = .60, p < .001), and TEI showed a higher likelihood of winning than PEI factors ( p < .0001 vs. .0001, CI 95% [1.64, 3.00] vs. [1.28, 2.07]). Higher TEI and TEI + PEI differences between the teams were associated with a greater likelihood of winning, but PEI differences were not. Key performance indicators and this performance assessment method might be useful to better understand what determines winning and to assist the overall training process and match management.

Likelihood of Breastfeeding Within the USDA's Food and Nutrition Service Special Supplemental Nutrition Program for Women, Infants, and Children Population.

PubMed

Houghtaling, Bailey; Byker Shanks, Carmen; Jenkins, Mica

2017-02-01

Breastfeeding is an important public health initiative. Low-income women benefiting from the U.S. Department of Agriculture's Food and Nutrition Service Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) are a prime population for breastfeeding promotion efforts. Research aim: This study aims to determine factors associated with increased likelihood of breastfeeding for WIC participants. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement guided the systematic review of literature. Database searches occurred in September and October 2014 and included studies limited to the previous 10 years. The following search terms were used: low-income; WIC; women, infants, and children; breastfeeding; breast milk; and maternal and child health. The criterion for inclusion was a study sample of women and children enrolled in the WIC program, thereby excluding non-United States-based research. Factors that increased the likelihood of breastfeeding for WIC participants included sociodemographic and health characteristics ( n = 17); environmental and media support ( n = 4); government policy ( n = 2); intention to breastfeed, breastfeeding in hospital, or previous breastfeeding experience ( n = 9); attitudes toward and knowledge of breastfeeding benefits ( n = 6); health care provider or social support; and time exposure to WIC services ( n = 5). The complexity of breastfeeding behaviors within this population is clear. Results provide multisectored insight for future research, policies, and practices in support of increasing breastfeeding rates among WIC participants.

Multilevel poisson regression modelling for determining factors of dengue fever cases in bandung

NASA Astrophysics Data System (ADS)

Arundina, Davila Rubianti; Tantular, Bertho; Pontoh, Resa Septiani

2017-03-01

Scralatina or Dengue Fever is a kind of fever caused by serotype virus which Flavivirus genus and be known as Dengue Virus. Dengue Fever caused by Aedes Aegipty Mosquito bites who infected by a dengue virus. The study was conducted in 151 villages in Bandung. Health Analysts believes that there are two factors that affect the dengue cases, Internal factor (individual) and external factor (environment). The data who used in this research is hierarchical data. The method is used for hierarchical data modelling is multilevel method. Which is, the level 1 is village and level 2 is sub-district. According exploration data analysis, the suitable Multilevel Method is Random Intercept Model. Penalized Quasi Likelihood (PQL) approach on multilevel Poisson is a proper analysis to determine factors that affecting dengue cases in the city of Bandung. Clean and Healthy Behavior factor from the village level have an effect on the number of cases of dengue fever in the city of Bandung. Factor from the sub-district level has no effect.

Make the most of your samples: Bayes factor estimators for high-dimensional models of sequence evolution.

PubMed

Baele, Guy; Lemey, Philippe; Vansteelandt, Stijn

2013-03-06

Accurate model comparison requires extensive computation times, especially for parameter-rich models of sequence evolution. In the Bayesian framework, model selection is typically performed through the evaluation of a Bayes factor, the ratio of two marginal likelihoods (one for each model). Recently introduced techniques to estimate (log) marginal likelihoods, such as path sampling and stepping-stone sampling, offer increased accuracy over the traditional harmonic mean estimator at an increased computational cost. Most often, each model's marginal likelihood will be estimated individually, which leads the resulting Bayes factor to suffer from errors associated with each of these independent estimation processes. We here assess the original 'model-switch' path sampling approach for direct Bayes factor estimation in phylogenetics, as well as an extension that uses more samples, to construct a direct path between two competing models, thereby eliminating the need to calculate each model's marginal likelihood independently. Further, we provide a competing Bayes factor estimator using an adaptation of the recently introduced stepping-stone sampling algorithm and set out to determine appropriate settings for accurately calculating such Bayes factors, with context-dependent evolutionary models as an example. While we show that modest efforts are required to roughly identify the increase in model fit, only drastically increased computation times ensure the accuracy needed to detect more subtle details of the evolutionary process. We show that our adaptation of stepping-stone sampling for direct Bayes factor calculation outperforms the original path sampling approach as well as an extension that exploits more samples. Our proposed approach for Bayes factor estimation also has preferable statistical properties over the use of individual marginal likelihood estimates for both models under comparison. Assuming a sigmoid function to determine the path between two competing models, we provide evidence that a single well-chosen sigmoid shape value requires less computational efforts in order to approximate the true value of the (log) Bayes factor compared to the original approach. We show that the (log) Bayes factors calculated using path sampling and stepping-stone sampling differ drastically from those estimated using either of the harmonic mean estimators, supporting earlier claims that the latter systematically overestimate the performance of high-dimensional models, which we show can lead to erroneous conclusions. Based on our results, we argue that highly accurate estimation of differences in model fit for high-dimensional models requires much more computational effort than suggested in recent studies on marginal likelihood estimation.

Make the most of your samples: Bayes factor estimators for high-dimensional models of sequence evolution

PubMed Central

2013-01-01

Background Accurate model comparison requires extensive computation times, especially for parameter-rich models of sequence evolution. In the Bayesian framework, model selection is typically performed through the evaluation of a Bayes factor, the ratio of two marginal likelihoods (one for each model). Recently introduced techniques to estimate (log) marginal likelihoods, such as path sampling and stepping-stone sampling, offer increased accuracy over the traditional harmonic mean estimator at an increased computational cost. Most often, each model’s marginal likelihood will be estimated individually, which leads the resulting Bayes factor to suffer from errors associated with each of these independent estimation processes. Results We here assess the original ‘model-switch’ path sampling approach for direct Bayes factor estimation in phylogenetics, as well as an extension that uses more samples, to construct a direct path between two competing models, thereby eliminating the need to calculate each model’s marginal likelihood independently. Further, we provide a competing Bayes factor estimator using an adaptation of the recently introduced stepping-stone sampling algorithm and set out to determine appropriate settings for accurately calculating such Bayes factors, with context-dependent evolutionary models as an example. While we show that modest efforts are required to roughly identify the increase in model fit, only drastically increased computation times ensure the accuracy needed to detect more subtle details of the evolutionary process. Conclusions We show that our adaptation of stepping-stone sampling for direct Bayes factor calculation outperforms the original path sampling approach as well as an extension that exploits more samples. Our proposed approach for Bayes factor estimation also has preferable statistical properties over the use of individual marginal likelihood estimates for both models under comparison. Assuming a sigmoid function to determine the path between two competing models, we provide evidence that a single well-chosen sigmoid shape value requires less computational efforts in order to approximate the true value of the (log) Bayes factor compared to the original approach. We show that the (log) Bayes factors calculated using path sampling and stepping-stone sampling differ drastically from those estimated using either of the harmonic mean estimators, supporting earlier claims that the latter systematically overestimate the performance of high-dimensional models, which we show can lead to erroneous conclusions. Based on our results, we argue that highly accurate estimation of differences in model fit for high-dimensional models requires much more computational effort than suggested in recent studies on marginal likelihood estimation. PMID:23497171

Determinants of new-onset diabetes in older adults—Results of a national cohort study.

PubMed

Tsai, Alan C; Lee, Shu-Hui

2015-10-01

Diabetes mellitus is prevalent in many countries around the world, but the potential causal factors are not clearly known. We attempted to determine the risk factors for new-onset diabetes in ≥53-year old Taiwanese. We analyzed the 1999 and 2003 datasets of the Taiwan Longitudinal Survey on Aging (TLSA). We performed logistic regression analyses to determine the cross-sectional and longitudinal (1999-2003) associations of the sociodemographic, lifestyle, and health-related variables with diabetes and new-onset diabetes, respectively. We excluded those who were diabetic at baseline in the longitudinal analysis. Results of the cross-sectional analysis showed that higher weight, past betel-quid chewing, IADL dependency, hypertension, heart disease, chronic kidney disease and depressive symptoms were positively associated with diabetes while alcohol drinking was negatively associated with diabetes. Longitudinal analysis showed that excessive weight, physical inactivity, depressive symptoms, and hypertension were associated with increased likelihood of new-onset diabetes while higher physical activity was associated with reduced likelihood of new-onset diabetes. Cigarette-smoking and moderate alcohol drinking showed no clear impacts on new-onset diabetes in older Taiwanese. Results show that excessive weight, physical inactivity, hypertension and depressive symptoms are the major risk factors for new-onset diabetes for both Eastern and Western populations, whereas smoking and alcohol drinking have varying impacts among these populations. Better understanding of these relationships should be helpful for planning effective health promotion strategies for reducing the risk of new-onset diabetes in older adults. Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Organizational adoption of preemployment drug testing.

PubMed

Spell, C S; Blum, T C

2001-04-01

This study explored the adoption of preemployment drug testing by 360 organizations. Survival models were developed that included internal organizational and labor market factors hypothesized to affect the likelihood of adoption of drug testing. Also considered was another set of variables that included social and political variables based on institutional theory. An event history analysis using Cox regressions indicated that both internal organizational and environmental variables predicted adoption of drug testing. Results indicate that the higher the proportion of drug testers in the worksite's industry, the more likely it would be to adopt drug testing. Also, the extent to which an organization uses an internal labor market, voluntary turnover rate, and the extent to which management perceives drugs to be a problem were related to likelihood of adoption of drug testing.

Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

PubMed

Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

2016-05-01

The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Antidepressant Prescribing by Pediatricians: A Mixed-Methods Analysis.

PubMed

Tulisiak, Anne K; Klein, Jillian A; Harris, Emily; Luft, Marissa J; Schroeder, Heidi K; Mossman, Sarah A; Varney, Sara T; Keeshin, Brooks R; Cotton, Sian; Strawn, Jeffrey R

2017-01-01

Among pediatricians, perceived knowledge of efficacy, tolerability, dosing, and side effects of antidepressants represent significant sources of variability in the use of these medications in youth with depressive and anxiety disorders. Importantly, the qualitative factors that relate to varying levels of comfort with antidepressants and willingness to prescribe are poorly understood. Using a mixed-methods approach, in-depth interviews were conducted with community-based and academic medical center-based pediatricians (N = 14). Interviews were audio recorded and iteratively coded; themes were then generated using inductive thematic analysis. The relationship between demographic factors, knowledge of antidepressants, dosing, and side effects, as well as prescribing likelihood scores for depressive disorders, anxiety disorders or co-morbid anxiety and depressive disorders, were evaluated using mixed models. Pediatricians reported antidepressants to be effective and well-tolerated. However, the likelihood of individual physicians initiating an antidepressant was significantly lower for anxiety disorders relative to depressive disorders with similar functional impairment. Pediatricians considered symptom severity/functional impairment, age and the availability of psychotherapy as they considered prescribing antidepressants to individual patients. Antidepressant choice was related to the physician׳s perceived knowledge and comfort with a particular antidepressant, financial factors, and the disorder-specific evidence base for that particular medication and consultation with mental health practitioners. Pediatricians noted similar efficacy and tolerability profiles for antidepressants in youth with depressive disorders and anxiety disorders, but tended to utilize "therapy first" approaches for anxiety disorders relative to depressive disorders. Parental and family factors that influenced prescribing of antidepressants by pediatricians included parental ambivalence, family-related dysfunction and impairment secondary to the child׳s psychopathology as well as the child׳s psychosocial milieu. Pediatricians consider patient- and family-specific challenges when choosing prescribing antidepressant medications and are, in general, less likely to prescribe antidepressants for youth with anxiety disorders compared to youth with depressive disorders. The lower likelihood of prescribing antidepressants for anxious youth is not related to perception of the efficacy or tolerability, but rather to a perception that anxiety disorders are less impairing and more appropriately managed with psychotherapy. Copyright © 2016 Mosby, Inc. All rights reserved.

Risk Factors for Recent Intimate Partner Violence among Methamphetamine-Using Men and Women

PubMed Central

Hayashi, Hitomi D.; Patterson, Thomas L.; Semple, Shirley J.; Fujimoto, Kayo; Stockman, Jamila K.

2016-01-01

The Substance Abuse, Violence, and HIV/AIDS (SAVA) syndemic model describes how the confluence of the three epidemics of substance abuse, violence, and HIV risk work synergistically to create excess burden among populations. We sought to identify risk factors associated with recent intimate partner violence (IPV) victimization among heterosexual methamphetamine (meth)-using men (n = 108) and women (n = 122) enrolled in FASTLANE-II, an HIV behavioral intervention in San Diego, CA. Women and men reported high rates of physical-only (women: 20%; men: 18%) and sexual (women: 25%; men: 23%) IPV. Multinomial regression analysis revealed that individuals who reported lower social support and individuals who reported a greater likelihood of engaging in risky sexual behaviors while high on meth were more likely to report IPV versus no IPV. Women who reported a greater likelihood of engaging in risky sexual behaviors while high on meth were 1.58 times more likely to report physical-only IPV versus no IPV, while men who reported similar behaviors were 1.15 times more likely to report physical-only IPV versus no IPV. Our findings highlight the influence of interpersonal factors on IPV. This research supports further study on gender-specific risk/protective factors and the development of gender-specific interventions targeting the SAVA syndemic among meth users. PMID:27163712

Prediction of primary vs secondary hypertension in children.

PubMed

Baracco, Rossana; Kapur, Gaurav; Mattoo, Tej; Jain, Amrish; Valentini, Rudolph; Ahmed, Maheen; Thomas, Ronald

2012-05-01

Despite current guidelines, variability exists in the workup of hypertensive children due to physician preferences. The study evaluates primary vs secondary hypertension diagnosis from investigations routinely performed in hypertensive children. This retrospective study included children 5 to 19 years with primary and secondary hypertension. The proportions of abnormal laboratory and imaging tests were compared between primary and secondary hypertension groups. Risk factors for primary vs secondary hypertension were evaluated by logistic regression and likelihood function analysis. Patients with secondary hypertension were younger (5-12 years) and had a higher proportion of abnormal creatinine, renal ultrasound, and echocardiogram findings. There was no significant difference in abnormal results of thyroid function, urine catecholamines, plasma renin, and aldosterone. Abnormal renal ultrasound findings and age were predictors of secondary hypertension by regression and likelihood function analysis. Children aged 5 to 12 years with abnormal renal ultrasound findings and high diastolic blood pressures are at higher risk for secondary hypertension that requires detailed evaluation. © 2012 Wiley Periodicals, Inc.

Epidemiology of Suicide Attempts among Youth Transitioning to Adulthood.

PubMed

Thompson, Martie P; Swartout, Kevin

2018-04-01

Suicide is the second leading cause of death for older adolescents and young adults. Although empirical literature has identified important risk factors of suicidal behavior, it is less understood if changes in risk factors correspond with changes in suicide risk. To address this knowledge gap, we assessed if there were different trajectories of suicidal behavior as youth transition into young adulthood and determined what time-varying risk factors predicted these trajectories. This study used four waves of data spanning approximately 13 years from the National Longitudinal Study of Adolescent Health. The sample included 9027 respondents who were 12-18 years old (M = 15.26; SD = 1.76) at Wave 1, 50% male, 17% Hispanic, and 58% White. The results indicated that 93.6% of the sample had a low likelihood for suicide attempts across time, 5.1% had an elevated likelihood of attempting suicide in adolescence but not young adulthood, and 1.3% had an elevated likelihood of attempting suicide during adolescence and adulthood. The likelihood of a suicide attempt corresponded with changes on depression, impulsivity, delinquency, alcohol problems, family and friend suicide history, and experience with partner violence. Determining how suicide risk changes as youth transition into young adulthood and what factors predict these changes can help prevent suicide. Interventions targeting these risk factors could lead to reductions in suicide attempts.

Constrained Stochastic Extended Redundancy Analysis.

PubMed

DeSarbo, Wayne S; Hwang, Heungsun; Stadler Blank, Ashley; Kappe, Eelco

2015-06-01

We devise a new statistical methodology called constrained stochastic extended redundancy analysis (CSERA) to examine the comparative impact of various conceptual factors, or drivers, as well as the specific predictor variables that contribute to each driver on designated dependent variable(s). The technical details of the proposed methodology, the maximum likelihood estimation algorithm, and model selection heuristics are discussed. A sports marketing consumer psychology application is provided in a Major League Baseball (MLB) context where the effects of six conceptual drivers of game attendance and their defining predictor variables are estimated. Results compare favorably to those obtained using traditional extended redundancy analysis (ERA).

Predictors of Discharge Disposition in Older Adults With Burns: A Study of the Burn Model Systems.

PubMed

Pham, Tam N; Carrougher, Gretchen J; Martinez, Erin; Lezotte, Dennis; Rietschel, Carly; Holavanahalli, Radha; Kowalske, Karen; Esselman, Peter C

2015-01-01

Older patients with burn injury have a greater likelihood for discharge to nursing facilities. Recent research indicates that older patients discharged to nursing facilities are two to three times as likely to die within a 3-year period relative to those discharged to home. In light of these poor long-term outcomes, we conducted this study to identify predictors for discharge to independent vs nonindependent living status in older patients hospitalized for burns. We retrospectively reviewed all older adults (age ≥ 55 years) who were prospectively enrolled in a longitudinal multicenter study of outcomes from 1993 to 2011. Patient, injury, and treatment outcomes data were analyzed. Recognizing that transfer to inpatient rehabilitation may have impacted final hospital discharge disposition: we assessed the likelihood of inpatient rehabilitation stay, based on identified predictors of inpatient rehabilitation. We subsequently performed a logistic regression analysis on the clustered, propensity-matched cohort to assess associations of burn and injury characteristics on the primary outcome of final discharge status. A total of 591 patients aged ≥55 years were treated and discharged alive from three participating U.S. burn centers during the study period. Mean burn size was 14.8% (SD 11.2%) and mean age was 66.7 years (SD 9.3 years). Ninety-three patients had an inpatient rehabilitation stay before discharge (15.7%). Significant factors predictive of inpatient rehabilitation included a burn >20% TBSA, mechanical ventilation, older age, range of motion deficits at acute care discharge, and study site. These factors were included in the propensity model. Four hundred seventy-one patients (80%) were discharged to independent living status. By matched propensity analysis, older age was significantly associated with a higher likelihood of discharge to nonindependent living (P < .01 in both the 65-74 age group and the oldest age group when compared with the 55-64 age group). Comorbidity (P < .01) and history of alcohol abuse (P < 0.01) were also predictive patient factors. Furthermore, clinical practice variations among the three study sites also constituted a significant factor in discharge disposition (both P < .01 when compared with the index study site). Older age remains an important risk factor for discharge to nonindependent living status, even after accounting for inpatient rehabilitation stay. This analysis, however, reveals significant variations in discharge disposition practices among the three participating study sites. We believe that these variations among burn centers need to be elucidated to better understand discharge disposition status in older patients with burns.

On the Performance of Maximum Likelihood versus Means and Variance Adjusted Weighted Least Squares Estimation in CFA

ERIC Educational Resources Information Center

Beauducel, Andre; Herzberg, Philipp Yorck

2006-01-01

This simulation study compared maximum likelihood (ML) estimation with weighted least squares means and variance adjusted (WLSMV) estimation. The study was based on confirmatory factor analyses with 1, 2, 4, and 8 factors, based on 250, 500, 750, and 1,000 cases, and on 5, 10, 20, and 40 variables with 2, 3, 4, 5, and 6 categories. There was no…

Measuring the Nursing Work Environment in Mainland China: Further Development of the Chinese Nursing Work Environment Scale.

PubMed

Shao, Jing; Tang, Leiwen; Ye, Zhihong

For the stabilization of the nursing profession in mainland China, a valid and reliable nursing work environment instrument, grounded in China's context, should be developed to better provide rigorous evidence for policy makers. The purpose of the current research was to further develop a scale that could capture the characteristics of the nursing work environment in mainland China. A convenience sample of 542 nurses employed in a tertiary hospital of mainland China completed the 108-item Chinese Nursing Work Environment (C-NWE) Scale (1st ed.). Items that did not differentiate between respondents with the highest and lowest 27% of total scores and those that did not meet criteria for factor loadings were set aside. Exploratory factor analysis based on the maximum likelihood method was used to identify the structure of the scale. The chi-square test was used to evaluate model fit, and expert review was conducted to test content validity. Reliability was estimated using Cronbach's alpha coefficient. The revised C-NWE Scale, which consists of nine subscales and 47 items, is a simplified version of the C-NWE (1st ed.). Using exploratory maximum likelihood factor analysis, the normed chi-square fit index for a nine-factor solution was 1.97. The content validity index for the total scale was 0.93; Cronbach's alpha was .94. Initial evidence of the psychometric properties of C-NWE scores was presented. Further studies could be conducted in various settings to identify the C-NWE Scale's validity and reliability.

Examining the Matthew effect on the motivation and ability to stay at work after heart disease.

PubMed

Meland, Eivind; Grønhaug, Siri; Oystese, Kristin; Mildestvedt, Thomas

2011-07-01

Cardiac rehabilitation should safeguard that socioeconomic factors or other differences that affect people's cardiovascular health are not further aggravated after healthcare treatment. The study examines whether socioeconomic status, emotional problems, or the severity of disease affect people's ability to continue to work after heart disease. We also examined if these effects can be explained by differences in motivational factors. 217 patients (41 women) from the Krokeide Rehabilitation Centre in Bergen participated. Multiple linear regression analysis was used to examine motivational differences, and logistic regression analysis was used to examine whether socioeconomic factors or other differences affected people's ability to continue to work after heart disease. Self-efficacy for future work strongly impacted the likelihood of being incapacitated for work during the 2-year follow-up. The household's total income and emotional problems were statistically significant related to patients dropping out from work in the course of the observation. The association between emotional problems and future work was mediated by motivational problems. The relation between income and future incapacity for work could not be explained by motivational factors. The study shows a clear Matthew effect on people's ability to continue to work after heart disease as low-income groups and people with emotional problems are more at risk of dropping out of work. This Matthew effect was, however, only explained by the motivational difficulties for the association between emotional distress and dropping out of work and not for the impact of household income on the likelihood of leaving work.

Does it really matter where women live? A multilevel analysis of the determinants of postnatal care in Nigeria.

PubMed

Ononokpono, Dorothy N; Odimegwu, Clifford O; Imasiku, Eunice N S; Adedini, Sunday A

2014-05-01

Although postnatal care is one of the major interventions recommended for the reduction of maternal and newborn deaths worldwide, almost two-third (56 %) of women in Nigeria do not receive postnatal care. Attempts to explain this situation have focused on individual and household level factors, but the role of community characteristics has received less attention.This study examines community factors associated with the receipt of postnatal care in Nigeria and the moderating effects of community factors on the association between individual factors and postnatal care. Data was drawn from the 2008 Nigeria Demographic and Health Survey, and a sample of 17,846 women aged 15-49 years was selected. We employed a multilevel logistic regression analysis to identify community factors associated with postnatal care. Our findings showed that significant variations in receiving postnatal care exist across communities. Specifically, Nigerian women's likelihood of receiving postnatal care is a function of where they reside. Living in communities with a high proportion of educated women (OR = 2.04; 95 % CI = 1.32-3.16; p < 0.001) and a high proportion of those who have had a health facility delivery (OR = 17.86; 95 % CI = 8.34-38.24; p < 0.001) was significantly associated with an increased likelihood of receiving postnatal care. Community women's education moderated the association between ethnic origin and postnatal care. Community variance in postnatal care was significant (τ = 10.352, p = 0.001). Community interventions aimed at improving postnatal care should take into account the community context in which women live. To close the gap in community variations in postnatal care, secondary and higher education for women, and health facility delivery should be increased in disadvantaged communities.

Supervisor Autonomy and Considerate Leadership Style are Associated with Supervisors' Likelihood to Accommodate Back Injured Workers.

PubMed

McGuire, Connor; Kristman, Vicki L; Shaw, William; Williams-Whitt, Kelly; Reguly, Paula; Soklaridis, Sophie

2015-09-01

To determine the association between supervisors' leadership style and autonomy and supervisors' likelihood of supporting job accommodations for back-injured workers. A cross-sectional study of supervisors from Canadian and US employers was conducted using a web-based, self-report questionnaire that included a case vignette of a back-injured worker. Autonomy and two dimensions of leadership style (considerate and initiating structure) were included as exposures. The outcome, supervisors' likeliness to support job accommodation, was measured with the Job Accommodation Scale (JAS). We conducted univariate analyses of all variables and bivariate analyses of the JAS score with each exposure and potential confounding factor. We used multivariable generalized linear models to control for confounding factors. A total of 796 supervisors participated. Considerate leadership style (β = .012; 95% CI .009-.016) and autonomy (β = .066; 95% CI .025-.11) were positively associated with supervisors' likelihood to accommodate after adjusting for appropriate confounding factors. An initiating structure leadership style was not significantly associated with supervisors' likelihood to accommodate (β = .0018; 95% CI -.0026 to .0061) after adjusting for appropriate confounders. Autonomy and a considerate leadership style were positively associated with supervisors' likelihood to accommodate a back-injured worker. Providing supervisors with more autonomy over decisions of accommodation and developing their considerate leadership style may aid in increasing work accommodation for back-injured workers and preventing prolonged work disability.

Comparison of Seven Methods for Boolean Factor Analysis and Their Evaluation by Information Gain.

PubMed

Frolov, Alexander A; Húsek, Dušan; Polyakov, Pavel Yu

2016-03-01

An usual task in large data set analysis is searching for an appropriate data representation in a space of fewer dimensions. One of the most efficient methods to solve this task is factor analysis. In this paper, we compare seven methods for Boolean factor analysis (BFA) in solving the so-called bars problem (BP), which is a BFA benchmark. The performance of the methods is evaluated by means of information gain. Study of the results obtained in solving BP of different levels of complexity has allowed us to reveal strengths and weaknesses of these methods. It is shown that the Likelihood maximization Attractor Neural Network with Increasing Activity (LANNIA) is the most efficient BFA method in solving BP in many cases. Efficacy of the LANNIA method is also shown, when applied to the real data from the Kyoto Encyclopedia of Genes and Genomes database, which contains full genome sequencing for 1368 organisms, and to text data set R52 (from Reuters 21578) typically used for label categorization.

Hurdle models for multilevel zero-inflated data via h-likelihood.

PubMed

Molas, Marek; Lesaffre, Emmanuel

2010-12-30

Count data often exhibit overdispersion. One type of overdispersion arises when there is an excess of zeros in comparison with the standard Poisson distribution. Zero-inflated Poisson and hurdle models have been proposed to perform a valid likelihood-based analysis to account for the surplus of zeros. Further, data often arise in clustered, longitudinal or multiple-membership settings. The proper analysis needs to reflect the design of a study. Typically random effects are used to account for dependencies in the data. We examine the h-likelihood estimation and inference framework for hurdle models with random effects for complex designs. We extend the h-likelihood procedures to fit hurdle models, thereby extending h-likelihood to truncated distributions. Two applications of the methodology are presented. Copyright © 2010 John Wiley & Sons, Ltd.

Hand on the wheel, mind on the mobile: an analysis of social factors contributing to texting while driving.

PubMed

Seiler, Steven J

2015-02-01

In an era defined by social technology, mobile phones provide constant connection to others. However, they also present a very dangerous situation when people choose to use their mobile phones while driving. In particular, exchanging text messages while driving has resulted in numerous accidents and fatalities. The purpose of this study is to examine social factors that lead people to text while driving. Specifically, using a multivariate logistic regression analysis of data from a 2010 survey by the Pew Research Center, variables for general mobile talk, driving while talking on a mobile, using the Internet on a mobile, sexting, and various motivations for texting were examined to determine factors that increase the likelihood of texting while driving. The findings suggest that people engage in mobile multiplexing (i.e., communication using two or more media on the mobile) while driving. Additionally, exchanging text messages in public, and consequently texting while driving, has become normalized. Furthermore, people are socialized into such behaviors through observing others texting while driving and using a mobile recklessly while driving. Finally, a number of motivations for texting were found to increase the likelihood of texting while driving significantly. Ultimately, the author contends that texting while driving has become a cultural artifact in the United States, which conflicts with driver safety as well as laws prohibiting texting while driving. The findings of this study could inform future awareness campaigns and technology developers to help establish a safer driving environment within the multitasking culture.

Factors influencing dental utilization by U.S. military recruits.

PubMed

Chisick, M C; Poindexter, F R; York, A K

1996-12-01

This study identifies factors that influence dental utilization by U.S. military recruits prior to entering military service. Data were collected between February and June 1994 at one recruit in-processing site per service using self-administered questionnaires. A prestratified, systematic, random sample of 2,711 Army, Air Force, Navy, and Marine recruits was drawn. Women and minorities were oversampled. Using logistic regression to determine what factors contribute to the likelihood of recruits having seen a dentist over the past year reveals that the likelihood is greater for females, singles, Air Force personnel, Native Americans, and the better educated; the likelihood is less for recruits who are black, above 19 years old, from the Midwest, Southwest, or Pacific regions of the U.S., and who perceive a need for dental care. Education is the strongest predictor of dental utilization prior to entering military service.

Assessment of parametric uncertainty for groundwater reactive transport modeling,

USGS Publications Warehouse

Shi, Xiaoqing; Ye, Ming; Curtis, Gary P.; Miller, Geoffery L.; Meyer, Philip D.; Kohler, Matthias; Yabusaki, Steve; Wu, Jichun

2014-01-01

The validity of using Gaussian assumptions for model residuals in uncertainty quantification of a groundwater reactive transport model was evaluated in this study. Least squares regression methods explicitly assume Gaussian residuals, and the assumption leads to Gaussian likelihood functions, model parameters, and model predictions. While the Bayesian methods do not explicitly require the Gaussian assumption, Gaussian residuals are widely used. This paper shows that the residuals of the reactive transport model are non-Gaussian, heteroscedastic, and correlated in time; characterizing them requires using a generalized likelihood function such as the formal generalized likelihood function developed by Schoups and Vrugt (2010). For the surface complexation model considered in this study for simulating uranium reactive transport in groundwater, parametric uncertainty is quantified using the least squares regression methods and Bayesian methods with both Gaussian and formal generalized likelihood functions. While the least squares methods and Bayesian methods with Gaussian likelihood function produce similar Gaussian parameter distributions, the parameter distributions of Bayesian uncertainty quantification using the formal generalized likelihood function are non-Gaussian. In addition, predictive performance of formal generalized likelihood function is superior to that of least squares regression and Bayesian methods with Gaussian likelihood function. The Bayesian uncertainty quantification is conducted using the differential evolution adaptive metropolis (DREAM(zs)) algorithm; as a Markov chain Monte Carlo (MCMC) method, it is a robust tool for quantifying uncertainty in groundwater reactive transport models. For the surface complexation model, the regression-based local sensitivity analysis and Morris- and DREAM(ZS)-based global sensitivity analysis yield almost identical ranking of parameter importance. The uncertainty analysis may help select appropriate likelihood functions, improve model calibration, and reduce predictive uncertainty in other groundwater reactive transport and environmental modeling.

Clinicians' practice environment is associated with a higher likelihood of recommending cesarean deliveries.

PubMed

Cheng, Yvonne W; Snowden, Jonathan M; Handler, Stephanie; Tager, Ira B; Hubbard, Alan; Caughey, Aaron B

2014-08-01

Little data exist regarding clinicians' role in the rising annual incidence rate of cesarean delivery in the US. We aimed to examine if clinicians' practice environment is associated with recommending cesarean deliveries. This is a survey study of clinicians who practice obstetrics in the US. This survey included eight clinical vignettes and 27 questions regarding clinicians' practice environment. Chi-square test and multivariable logistic regression were used for statistical comparison. Of 27 675 survey links sent, 3646 clinicians received and opened the survey electronically, and 1555 (43%) participated and 1486 (94%) completed the survey. Clinicians were categorized into three groups based on eight common obstetric vignettes as: more likely (n = 215), average likelihood (n = 1099), and less likely (n = 168) to recommend cesarean. Clinician environment factors associated with a higher likelihood of recommending cesarean included Laborists/Hospitalists practice model (p < 0.001), as-needed anesthesia support (p = 0.003), and rural/suburban practice setting (p < 0.001). We identified factors in clinicians' environment associated with their likelihood of recommending cesarean delivery. The decision to recommend cesarean delivery is a complicated one and is likely not solely based on patient factors.

Box-Cox transformation for QTL mapping.

PubMed

Yang, Runqing; Yi, Nengjun; Xu, Shizhong

2006-01-01

The maximum likelihood method of QTL mapping assumes that the phenotypic values of a quantitative trait follow a normal distribution. If the assumption is violated, some forms of transformation should be taken to make the assumption approximately true. The Box-Cox transformation is a general transformation method which can be applied to many different types of data. The flexibility of the Box-Cox transformation is due to a variable, called transformation factor, appearing in the Box-Cox formula. We developed a maximum likelihood method that treats the transformation factor as an unknown parameter, which is estimated from the data simultaneously along with the QTL parameters. The method makes an objective choice of data transformation and thus can be applied to QTL analysis for many different types of data. Simulation studies show that (1) Box-Cox transformation can substantially increase the power of QTL detection; (2) Box-Cox transformation can replace some specialized transformation methods that are commonly used in QTL mapping; and (3) applying the Box-Cox transformation to data already normally distributed does not harm the result.

Modeling of 2D diffusion processes based on microscopy data: parameter estimation and practical identifiability analysis.

PubMed

Hock, Sabrina; Hasenauer, Jan; Theis, Fabian J

2013-01-01

Diffusion is a key component of many biological processes such as chemotaxis, developmental differentiation and tissue morphogenesis. Since recently, the spatial gradients caused by diffusion can be assessed in-vitro and in-vivo using microscopy based imaging techniques. The resulting time-series of two dimensional, high-resolutions images in combination with mechanistic models enable the quantitative analysis of the underlying mechanisms. However, such a model-based analysis is still challenging due to measurement noise and sparse observations, which result in uncertainties of the model parameters. We introduce a likelihood function for image-based measurements with log-normal distributed noise. Based upon this likelihood function we formulate the maximum likelihood estimation problem, which is solved using PDE-constrained optimization methods. To assess the uncertainty and practical identifiability of the parameters we introduce profile likelihoods for diffusion processes. As proof of concept, we model certain aspects of the guidance of dendritic cells towards lymphatic vessels, an example for haptotaxis. Using a realistic set of artificial measurement data, we estimate the five kinetic parameters of this model and compute profile likelihoods. Our novel approach for the estimation of model parameters from image data as well as the proposed identifiability analysis approach is widely applicable to diffusion processes. The profile likelihood based method provides more rigorous uncertainty bounds in contrast to local approximation methods.

Risk Factors for Hearing Decrement Among U.S. Air Force Aviation-Related Personnel.

PubMed

Greenwell, Brandon M; Tvaryanas, Anthony P; Maupin, Genny M

2018-02-01

The purpose of this study was to analyze historical hearing sensitivity data to determine factors associated with an occupationally significant change in hearing sensitivity in U.S. Air Force aviation-related personnel. This study was a longitudinal, retrospective cohort analysis of audiogram records for Air Force aviation-related personnel on active duty during calendar year 2013 without a diagnosis of non-noise-related hearing loss. The outcomes of interest were raw change in hearing sensitivity from initial baseline to 2013 audiogram and initial occurrence of a significant threshold shift (STS) and non-H1 audiogram profile. Potential predictor variables included age and elapsed time in cohort for each audiogram, gender, and Air Force Specialty Code. Random forest analyses conducted on a learning sample were used to identify relevant predictor variables. Mixed effects models were fitted to a separate validation sample to make statistical inferences. The final dataset included 167,253 nonbaseline audiograms on 10,567 participants. Only the interaction between time since baseline audiogram and age was significantly associated with raw change in hearing sensitivity by STS metric. None of the potential predictors were associated with the likelihood for an STS. Time since baseline audiogram, age, and their interaction were significantly associated with the likelihood for a non-HI hearing profile. In this study population, age and elapsed time since baseline audiogram were modestly associated with decreased hearing sensitivity and increased likelihood for a non-H1 hearing profile. Aircraft type, as determined from Air Force Specialty Code, was not associated with changes in hearing sensitivity by STS metric.Greenwell BM, Tvaryanas AP, Maupin GM. Risk factors for hearing decrement among U.S. Air Force aviation-related personnel. Aerosp Med Hum Perform. 2018; 89(2):80-86.

Patient Factors Influencing Respiratory-Related Clinician Actions in Chronic Obstructive Pulmonary Disease Screening.

PubMed

Wadland, William C; Zubek, Valentina Bayer; Clerisme-Beaty, Emmanuelle M; Ríos-Bedoya, Carlos F; Yawn, Barbara P

2017-01-01

The purpose of this study was to identify patient-related factors that may explain the increased likelihood of receiving a respiratory-related clinician action in patients identified to be at risk for chronic obstructive pulmonary disease in a U.S.-based pragmatic study of chronic obstructive pulmonary disease screening. This post hoc analysis (conducted in 2014-2015) of the Screening, Evaluating and Assessing Rate Changes of Diagnosing Respiratory Conditions in Primary Care 1 (SEARCH1) study (conducted in 2010-2011), used the chronic obstructive pulmonary disease Population Screener questionnaire in 112 primary care practices. Anyone with a previous chronic obstructive pulmonary disease diagnosis was excluded. Multivariate logistic regression modeling was used to assess patient factors associated with the likelihood of receiving an respiratory-related clinician action following positive screening. Overall, 994 of 6,497 (15%) screened positive and were considered at risk for chronic obstructive pulmonary disease. However, only 187 of the 994 patients (19%) who screened positive received a respiratory-related clinician action. The chances of receiving a respiratory-related clinician action were significantly increased in patients who visited their physician with a respiratory issue (p<0.05) or had already been prescribed a respiratory medication (p<0.05). Most (81%) patients who screened positive or had a respiratory-related clinician action had one or more comorbidity, including cardiovascular disease (68%), diabetes (30%), depression/anxiety (26%), asthma (11%), and cancer (9%). Routine chronic obstructive pulmonary disease screening appears to promote respiratory-related clinician actions in patients with a high likelihood for disease who have respiratory complaints or already use prescribed respiratory medication. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Augmenting Latent Dirichlet Allocation and Rank Threshold Detection with Ontologies

DTIC Science & Technology

2010-03-01

Probabilistic Latent Semantic Indexing (PLSI) is an automated indexing information retrieval model [20]. It is based on a statistical latent class model which is...uses a statistical foundation that is more accurate in finding hidden semantic relationships [20]. The model uses factor analysis of count data, number...principle of statistical infer- ence which asserts that all of the information in a sample is contained in the likelihood function [20]. The statistical

Systematic review with network meta-analysis: the efficacy of anti-tumour necrosis factor-alpha agents for the treatment of ulcerative colitis.

PubMed

Stidham, R W; Lee, T C H; Higgins, P D R; Deshpande, A R; Sussman, D A; Singal, A G; Elmunzer, B J; Saini, S D; Vijan, S; Waljee, A K

2014-04-01

Antibodies against tumour necrosis factor-alpha (anti-TNF) are effective therapies in the treatment of ulcerative colitis (UC), but their comparative efficacy is unknown. To perform a network meta-analysis comparing the efficacy of anti-TNF agents in UC. After screening 506 studies, reviewers extracted information on seven studies. Traditional meta-analysis (TMA) was used to compare each anti-TNF agent to placebo. Bayesian network meta-analysis (NMA) was performed to compare the effects of anti-TNF agents to placebo. In addition, sample sizes for comparative efficacy trials were calculated. Compared to placebo, TMA revealed that anti-TNF agents result in a higher likelihood of induction of remission and response (RR: 2.45, 95% CI: 1.72-3.47 and RR: 1.65, 95% CI: 1.37-1.99 respectively) as well as maintenance of remission and response (RR: 2.00, 95% CI: 1.52-2.62 and RR: 1.76, 95% CI: 1.46-2.14 respectively). Individually, infliximab, adalimumab and goliumumab resulted in a higher likelihood of induction and maintenance for both remission and response. NMA found nonsignificant trends in comparisons of the individual agents. The required sample sizes for direct head-to-head trials between infliximab and adalimumab for induction and maintenance are 174 and 204 subjects respectively. This study demonstrates that, compared to placebo, infliximab, adalimumab and golimumab are all effective for the induction and maintenance of remission in ulcerative colitis. However, network meta-analysis demonstrates that no single agent is clinically superior to the others and therefore, other factors such as cost, safety, route of administration and patient preference should dictate our choice of anti-TNF agents. A randomised comparative efficacy trial between infliximab and adalimumab in UC is of practical size and should be performed. © 2014 John Wiley & Sons Ltd.

Using the Karolinska Scales of Personality on male juvenile delinquents: relationships between scales and factor structure.

PubMed

Dåderman, Anna M; Hellström, Ake; Wennberg, Peter; Törestad, Bertil

2005-01-01

The aim of the present study was to investigate relationships between scales from the Karolinska Scales of Personality (KSP) and the factor structure of the KSP in a sample of male juvenile delinquents. The KSP was administered to a group of male juvenile delinquents (n=55, mean age 17 years; standard deviation=1.2) from four Swedish national correctional institutions for serious offenders. As expected, the KSP showed appropriate correlations between the scales. Factor analysis (maximum likelihood) arrived at a four-factor solution in this sample, which is in line with previous research performed in a non-clinical sample of Swedish males. More research is needed in a somewhat larger sample of juvenile delinquents in order to confirm the present results regarding the factor solution.

Cumulative risk and AIDS-orphanhood: interactions of stigma, bullying and poverty on child mental health in South Africa.

PubMed

Cluver, Lucie; Orkin, Mark

2009-10-01

Research shows that AIDS-orphaned children are more likely to experience clinical-range psychological problems. Little is known about possible interactions between factors mediating these high distress levels. We assessed how food insecurity, bullying, and AIDS-related stigma interacted with each other and with likelihood of experiencing clinical-range disorder. In South Africa, 1025 adolescents completed standardised measures of depression, anxiety and post-traumatic stress. 52 potential mediators were measured, including AIDS-orphanhood status. Logistic regressions and hierarchical log-linear modelling were used to identify interactions among significant risk factors. Food insecurity, stigma and bullying all independently increased likelihood of disorder. Poverty and stigma were found to interact strongly, and with both present, likelihood of disorder rose from 19% to 83%. Similarly, bullying interacted with AIDS-orphanhood status, and with both present, likelihood of disorder rose from 12% to 76%. Approaches to alleviating psychological distress amongst AIDS-affected children must address cumulative risk effects.

Factors associated with single-vehicle and multi-vehicle road traffic collision injuries in Ireland.

PubMed

Donnelly-Swift, Erica; Kelly, Alan

2016-12-01

Generalised linear regression models were used to identify factors associated with fatal/serious road traffic collision injuries for single- and multi-vehicle collisions. Single-vehicle collisions and multi-vehicle collisions occurring during the hours of darkness or on a wet road surface had reduced likelihood of a fatal/serious injury. Single-vehicle 'driver with passengers' collisions occurring at junctions or on a hill/gradient were less likely to result in a fatal/serious injury. Multi-vehicle rear-end/angle collisions had reduced likelihood of a fatal/serious injury. Single-vehicle 'driver only' collisions and multi-vehicle collisions occurring on a public/bank holiday or on a hill/gradient were more likely to result in a fatal/serious injury. Single-vehicle collisions involving male drivers had increased likelihood of a fatal/serious injury and single-vehicle 'driver with passengers' collisions involving drivers under the age of 25 years also had increased likelihood of a fatal/serious injury. Findings can enlighten decision-makers to circumstances leading to fatal/serious injuries.

Dynamic Histogram Analysis To Determine Free Energies and Rates from Biased Simulations.

PubMed

Stelzl, Lukas S; Kells, Adam; Rosta, Edina; Hummer, Gerhard

2017-12-12

We present an algorithm to calculate free energies and rates from molecular simulations on biased potential energy surfaces. As input, it uses the accumulated times spent in each state or bin of a histogram and counts of transitions between them. Optimal unbiased equilibrium free energies for each of the states/bins are then obtained by maximizing the likelihood of a master equation (i.e., first-order kinetic rate model). The resulting free energies also determine the optimal rate coefficients for transitions between the states or bins on the biased potentials. Unbiased rates can be estimated, e.g., by imposing a linear free energy condition in the likelihood maximization. The resulting "dynamic histogram analysis method extended to detailed balance" (DHAMed) builds on the DHAM method. It is also closely related to the transition-based reweighting analysis method (TRAM) and the discrete TRAM (dTRAM). However, in the continuous-time formulation of DHAMed, the detailed balance constraints are more easily accounted for, resulting in compact expressions amenable to efficient numerical treatment. DHAMed produces accurate free energies in cases where the common weighted-histogram analysis method (WHAM) for umbrella sampling fails because of slow dynamics within the windows. Even in the limit of completely uncorrelated data, where WHAM is optimal in the maximum-likelihood sense, DHAMed results are nearly indistinguishable. We illustrate DHAMed with applications to ion channel conduction, RNA duplex formation, α-helix folding, and rate calculations from accelerated molecular dynamics. DHAMed can also be used to construct Markov state models from biased or replica-exchange molecular dynamics simulations. By using binless WHAM formulated as a numerical minimization problem, the bias factors for the individual states can be determined efficiently in a preprocessing step and, if needed, optimized globally afterward.

Likelihood of Breastfeeding Within the USDA’s Food and Nutrition Service Special Supplemental Nutrition Program for Women, Infants, and Children Population: A Systematic Review of the Literature

PubMed Central

Houghtaling, Bailey; Shanks, Carmen Byker; Jenkins, Mica

2017-01-01

Background Breastfeeding is an important public health initiative. Low-income women benefiting from the U.S. Department of Agriculture’s Food and Nutrition Service Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) are a prime population for breastfeeding promotion efforts. Research aim This study aims to determine factors associated with increased likelihood of breastfeeding for WIC participants. Methods The Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement guided the systematic review of literature. Database searches occurred in September and October 2014 and included studies limited to the previous 10 years. The following search terms were used: low-income; WIC; women, infants, and children; breastfeeding; breast milk; and maternal and child health. The criterion for inclusion was a study sample of women and children enrolled in the WIC program, thereby excluding non-United States–based research. Results Factors that increased the likelihood of breastfeeding for WIC participants included sociodemographic and health characteristics (n = 17); environmental and media support (n = 4); government policy (n = 2); intention to breastfeed, breastfeeding in hospital, or previous breastfeeding experience (n = 9); attitudes toward and knowledge of breastfeeding benefits (n = 6); health care provider or social support; and time exposure to WIC services (n = 5). Conclusion The complexity of breastfeeding behaviors within this population is clear. Results provide multisectored insight for future research, policies, and practices in support of increasing breastfeeding rates among WIC participants. PMID:28135478

Family emergency preparedness plans in severe tornadoes.

PubMed

Cong, Zhen; Liang, Daan; Luo, Jianjun

2014-01-01

Tornadoes, with warnings usually issued just minutes before their touchdowns, pose great threats to properties and people's physical and mental health. Few studies have empirically investigated the association of family emergency preparedness planning and observed protective behaviors in the context of tornadoes. The purpose of this study was to examine predictors for the action of taking shelter at the time of tornadoes. Specifically, this study investigated whether having a family emergency preparedness plan was associated with higher likelihood of taking shelter upon receiving tornado warnings. This study also examined the effects of socioeconomic status and functional limitations on taking such actions. A telephone survey based on random sampling was conducted in 2012 with residents in Tuscaloosa AL and Joplin MO. Each city experienced considerable damages, injuries, and casualties after severe tornadoes (EF-4 and EF-5) in 2011. The working sample included 892 respondents. Analysis was conducted in early 2013. Logistic regression identified emergency preparedness planning as the only shared factor that increased the likelihood of taking shelter in both cities and the only significant factor in Joplin. In Tuscaloosa, being female and white also increased the likelihood of taking shelter. Disability was not found to have an effect. This study provided empirical evidence on the importance of having a family emergency preparedness plan in mitigating the risk of tornadoes. The findings could be applied to other rapid-onset disasters. © 2013 American Journal of Preventive Medicine Published by American Journal of Preventive Medicine All rights reserved.

Self-compassion, pain, and breaking a social contract.

PubMed

Purdie, Fiona; Morley, Stephen

2015-11-01

Self-compassion is the ability to respond to one's failures, shortcomings, and difficulties with kindness and openness rather than criticism. This study, which might be regarded as a proof-of-concept study, aimed to establish whether self-compassion is associated with expected emotional responses and the likelihood of responding with problem solving, support seeking, distraction, avoidance, rumination, or catastrophizing to unpleasant self-relevant events occurring in 3 social contexts. Sixty chronic pain patients were presented with 6 vignettes describing scenes in which the principal actor transgressed a social contract with negative interpersonal consequences. Vignettes represented 2 dimensions: (1) whether pain or a nonpain factor interrupted the fulfillment of the contract and (2) variation in the social setting (work, peer, and family). The Self-Compassion Scale was the covariate in the analysis. Higher levels of self-compassion were associated with significantly lower negative affect and lower reported likelihood of avoidance, catastrophizing, and rumination. Self-compassion did not interact with pain vs nonpain factor. Work-related vignettes were rated as more emotional and more likely to be associated with avoidance, catastrophizing, and rumination and less likelihood of problem solving. The findings suggest that self-compassion warrants further investigation in the chronic pain population both regarding the extent of its influence as a trait and in terms of the potential to enhance chronic pain patients' ability to be self-compassionate, with a view to its therapeutic utility in enhancing psychological well-being and adjustment. Limitations regarding the possible criterion contamination and the generalizability of vignette studies are discussed.

Maximum Likelihood Factor Analysis of the Effects of Chronic Centrifugation on the Structural Development of the Musculoskeletal System of the Rat

NASA Technical Reports Server (NTRS)

Amtmann, E.; Kimura, T.; Oyama, J.; Doden, E.; Potulski, M.

1979-01-01

At the age of 30 days female Sprague-Dawley rats were placed on a 3.66 m radius centrifuge and subsequently exposed almost continuously for 810 days to either 2.76 or 4.15 G. An age-matched control group of rats was raised near the centrifuge facility at earth gravity. Three further control groups of rats were obtained from the animal colony and sacrificed at the age of 34, 72 and 102 days. A total of 16 variables were simultaneously factor analyzed by maximum-likelihood extraction routine and the factor loadings presented after-rotation to simple structure by a varimax rotation routine. The variables include the G-load, age, body mass, femoral length and cross-sectional area, inner and outer radii, density and strength at the mid-length of the femur, dry weight of gluteus medius, semimenbranosus and triceps surae muscles. Factor analyses on A) all controls, B) all controls and the 2.76 G group, and C) all controls and centrifuged animals, produced highly similar loading structures of three common factors which accounted for 74%, 68% and 68%. respectively, of the total variance. The 3 factors were interpreted as: 1. An age and size factor which stimulates the growth in length and diameter and increases the density and strength of the femur. This factor is positively correlated with G-load but is also active in the control animals living at earth gravity. 2. A growth inhibition factor which acts on body size, femoral length and on both the outer and inner radius at mid-length of the femur. This factor is intensified by centrifugation.

Factors associated with persons with disability employment in India: a cross-sectional study.

PubMed

Naraharisetti, Ramya; Castro, Marcia C

2016-10-07

Over twenty million persons with disability in India are increasingly being offered poverty alleviation strategies, including employment programs. This study employs a spatial analytic approach to identify correlates of employment among persons with disability in India, considering sight, speech, hearing, movement, and mental disabilities. Based on 2001 Census data, this study utilizes linear regression and spatial autoregressive models to identify factors associated with the proportion employed among persons with disability at the district level. Models stratified by rural and urban areas were also considered. Spatial autoregressive models revealed that different factors contribute to employment of persons with disability in rural and urban areas. In rural areas, having mental disability decreased the likelihood of employment, while being female and having movement, or sight impairment (compared to other disabilities) increased the likelihood of employment. In urban areas, being female and illiterate decreased the likelihood of employment but having sight, mental and movement impairment (compared to other disabilities) increased the likelihood of employment. Poverty alleviation programs designed for persons with disability in India should account for differences in employment by disability types and should be spatially targeted. Since persons with disability in rural and urban areas have different factors contributing to their employment, it is vital that government and service-planning organizations account for these differences when creating programs aimed at livelihood development.

Supervisor Autonomy and Considerate Leadership Style are Associated with Supervisors’ Likelihood to Accommodate Back Injured Workers

PubMed Central

McGuire, Connor; Kristman, Vicki L; Williams-Whitt, Kelly; Reguly, Paula; Shaw, William; Soklaridis, Sophie

2015-01-01

PURPOSE To determine the association between supervisors’ leadership style and autonomy and supervisors’ likelihood of supporting job accommodations for back-injured workers. METHODS A cross-sectional study of supervisors from Canadian and US employers was conducted using a web-based, self-report questionnaire that included a case vignette of a back-injured worker. Autonomy and two dimensions of leadership style (considerate and initiating structure) were included as exposures. The outcome, supervisors’ likeliness to support job accommodation, was measured with the Job Accommodation Scale. We conducted univariate analyses of all variables and bivariate analyses of the JAS score with each exposure and potential confounding factor. We used multivariable generalized linear models to control for confounding factors. RESULTS A total of 796 supervisors participated. Considerate leadership style (β= .012; 95% CI: .009–.016) and autonomy (β= .066; 95% CI: .025–.11) were positively associated with supervisors’ likelihood to accommodate after adjusting for appropriate confounding factors. An initiating structure leadership style was not significantly associated with supervisors’ likelihood to accommodate (β = .0018; 95% CI: −.0026–.0061) after adjusting for appropriate confounders. CONCLUSIONS Autonomy and a considerate leadership style were positively associated with supervisors’ likelihood to accommodate a back-injured worker. Providing supervisors with more autonomy over decisions of accommodation and developing their considerate leadership style may aid in increasing work accommodation for back-injured workers and preventing prolonged work disability. PMID:25595332

A review of factors associated with greater likelihood of suicide attempts and suicide deaths in bipolar disorder: Part II of a report of the International Society for Bipolar Disorders Task Force on Suicide in Bipolar Disorder.

PubMed

Schaffer, Ayal; Isometsä, Erkki T; Azorin, Jean-Michel; Cassidy, Frederick; Goldstein, Tina; Rihmer, Zoltán; Sinyor, Mark; Tondo, Leonardo; Moreno, Doris H; Turecki, Gustavo; Reis, Catherine; Kessing, Lars Vedel; Ha, Kyooseob; Weizman, Abraham; Beautrais, Annette; Chou, Yuan-Hwa; Diazgranados, Nancy; Levitt, Anthony J; Zarate, Carlos A; Yatham, Lakshmi

2015-11-01

Many factors influence the likelihood of suicide attempts or deaths in persons with bipolar disorder. One key aim of the International Society for Bipolar Disorders Task Force on Suicide was to summarize the available literature on the presence and magnitude of effect of these factors. A systematic review of studies published from 1 January 1980 to 30 May 2014 identified using keywords 'bipolar disorder' and 'suicide attempts or suicide'. This specific paper examined all reports on factors putatively associated with suicide attempts or suicide deaths in bipolar disorder samples. Factors were subcategorized into: (1) sociodemographics, (2) clinical characteristics of bipolar disorder, (3) comorbidities, and (4) other clinical variables. We identified 141 studies that examined how 20 specific factors influenced the likelihood of suicide attempts or deaths. While the level of evidence and degree of confluence varied across factors, there was at least one study that found an effect for each of the following factors: sex, age, race, marital status, religious affiliation, age of illness onset, duration of illness, bipolar disorder subtype, polarity of first episode, polarity of current/recent episode, predominant polarity, mood episode characteristics, psychosis, psychiatric comorbidity, personality characteristics, sexual dysfunction, first-degree family history of suicide or mood disorders, past suicide attempts, early life trauma, and psychosocial precipitants. There is a wealth of data on factors that influence the likelihood of suicide attempts and suicide deaths in people with bipolar disorder. Given the heterogeneity of study samples and designs, further research is needed to replicate and determine the magnitude of effect of most of these factors. This approach can ultimately lead to enhanced risk stratification for patients with bipolar disorder. © The Royal Australian and New Zealand College of Psychiatrists 2015.

A review of factors associated with greater likelihood of suicide attempts and suicide deaths in bipolar disorder: Part II of a report of the International Society for Bipolar Disorders Task Force on Suicide in Bipolar Disorder

PubMed Central

Schaffer, Ayal; Isometsä, Erkki T; Azorin, Jean-Michel; Cassidy, Frederick; Goldstein, Tina; Rihmer, Zoltán; Sinyor, Mark; Tondo, Leonardo; Moreno, Doris H; Turecki, Gustavo; Reis, Catherine; Kessing, Lars Vedel; Ha, Kyooseob; Weizman, Abraham; Beautrais, Annette; Chou, Yuan-Hwa; Diazgranados, Nancy; Levitt, Anthony J; Zarate, Carlos A; Yatham, Lakshmi

2018-01-01

Objectives Many factors influence the likelihood of suicide attempts or deaths in persons with bipolar disorder. One key aim of the International Society for Bipolar Disorders Task Force on Suicide was to summarize the available literature on the presence and magnitude of effect of these factors. Methods A systematic review of studies published from 1 January 1980 to 30 May 2014 identified using keywords ‘bipolar disorder’ and ‘suicide attempts or suicide’. This specific paper examined all reports on factors putatively associated with suicide attempts or suicide deaths in bipolar disorder samples. Factors were subcategorized into: (1) sociodemographics, (2) clinical characteristics of bipolar disorder, (3) comorbidities, and (4) other clinical variables. Results We identified 141 studies that examined how 20 specific factors influenced the likelihood of suicide attempts or deaths. While the level of evidence and degree of confluence varied across factors, there was at least one study that found an effect for each of the following factors: sex, age, race, marital status, religious affiliation, age of illness onset, duration of illness, bipolar disorder subtype, polarity of first episode, polarity of current/recent episode, predominant polarity, mood episode characteristics, psychosis, psychiatric comorbidity, personality characteristics, sexual dysfunction, first-degree family history of suicide or mood disorders, past suicide attempts, early life trauma, and psychosocial precipitants. Conclusion There is a wealth of data on factors that influence the likelihood of suicide attempts and suicide deaths in people with bipolar disorder. Given the heterogeneity of study samples and designs, further research is needed to replicate and determine the magnitude of effect of most of these factors. This approach can ultimately lead to enhanced risk stratification for patients with bipolar disorder. PMID:26175498

Bayesian structural equation modeling: a more flexible representation of substantive theory.

PubMed

Muthén, Bengt; Asparouhov, Tihomir

2012-09-01

This article proposes a new approach to factor analysis and structural equation modeling using Bayesian analysis. The new approach replaces parameter specifications of exact zeros with approximate zeros based on informative, small-variance priors. It is argued that this produces an analysis that better reflects substantive theories. The proposed Bayesian approach is particularly beneficial in applications where parameters are added to a conventional model such that a nonidentified model is obtained if maximum-likelihood estimation is applied. This approach is useful for measurement aspects of latent variable modeling, such as with confirmatory factor analysis, and the measurement part of structural equation modeling. Two application areas are studied, cross-loadings and residual correlations in confirmatory factor analysis. An example using a full structural equation model is also presented, showing an efficient way to find model misspecification. The approach encompasses 3 elements: model testing using posterior predictive checking, model estimation, and model modification. Monte Carlo simulations and real data are analyzed using Mplus. The real-data analyses use data from Holzinger and Swineford's (1939) classic mental abilities study, Big Five personality factor data from a British survey, and science achievement data from the National Educational Longitudinal Study of 1988.

THESEUS: maximum likelihood superpositioning and analysis of macromolecular structures

PubMed Central

Theobald, Douglas L.; Wuttke, Deborah S.

2008-01-01

Summary THESEUS is a command line program for performing maximum likelihood (ML) superpositions and analysis of macromolecular structures. While conventional superpositioning methods use ordinary least-squares (LS) as the optimization criterion, ML superpositions provide substantially improved accuracy by down-weighting variable structural regions and by correcting for correlations among atoms. ML superpositioning is robust and insensitive to the specific atoms included in the analysis, and thus it does not require subjective pruning of selected variable atomic coordinates. Output includes both likelihood-based and frequentist statistics for accurate evaluation of the adequacy of a superposition and for reliable analysis of structural similarities and differences. THESEUS performs principal components analysis for analyzing the complex correlations found among atoms within a structural ensemble. PMID:16777907

Adjusting for founder relatedness in a linkage analysis using prior information.

PubMed

Sheehan, N A; Egeland, T

2008-01-01

In genetic linkage studies, while the pedigrees are generally known, background relatedness between the founding individuals, assumed by definition to be unrelated, can seriously affect the results of the analysis. Likelihood approaches to relationship estimation from genetic marker data can all be expressed in terms of finding the most likely pedigree connecting the individuals of interest. When the true relationship is the main focus, the set of all possible alternative pedigrees can be too large to consider. However, prior information is often available which, when incorporated in a formal and structured way, can restrict this set to a manageable size thus enabling the calculation of a posterior distribution from which inferences can be drawn. Here, the unknown relationships are more of a nuisance factor than of interest in their own right, so the focus is on adjusting the results of the analysis rather than on direct estimation. In this paper, we show how prior information on founder relationships can be exploited in some applications to generate a set of candidate extended pedigrees. We then weight the relevant pedigree-specific likelihoods by their posterior probabilities to adjust the lod score statistics. (c) 2007 S. Karger AG, Basel

Screening for domestic violence in public welfare offices: an analysis of case manager and client interactions.

PubMed

Lindhorst, Taryn; Meyers, Marcia; Casey, Erin

2008-01-01

Despite a high prevalence of domestic violence among welfare clients, most studies of the implementation of the Family Violence Option (FVO) under welfare reform find that women rarely receive domestic violence services in welfare offices. This study reviews findings from current research on the factors that improve the likelihood that women will reveal their domestic violence experiences to service personnel, and uses the guidelines drawn from this review to evaluate domestic violence screening practices in welfare offices using 782 transcribed interviews between welfare workers and clients from 11 sites in four states. The analysis found that only 9.3% of case encounters involved screening for domestic violence. Screening rates differed by state, interview type, and length of worker employment. Qualitative analysis of the interviews showed that the majority of screening by workers was routine or consisted of informing clients of the domestic violence policy without asking about abuse. Only 1.2% of the interviews incorporated at least two of the procedures that increase the likelihood of disclosure among domestic violence survivors, suggesting deeply inadequate approaches to screening for abuse within the context of welfare offices, and a need for improved training, protocol, and monitoring of FVO implementation.

Risk factors for prelacteal feeding in sub-Saharan Africa: a multilevel analysis of population data from twenty-two countries.

PubMed

Berde, Anselm S; Ozcebe, Hilal

2017-08-01

To examine the risk factors of prelacteal feeding (PLF) among mothers in sub-Saharan Africa (SSA). We pooled data from Demographic and Health Surveys in twenty-two SSA countries. The key outcome variable was PLF. A multilevel logistic regression model was used to explore factors associated with PLF. Demographic and Health Surveys in twenty-two SSA countries. Mother-baby pairs (n 95348). Prevalence of PLF in SSA was 32·2 %. Plain water (22·1 %), milk other than breast milk (5·0 %) and sugar or glucose water (4·1 %) were the predominant prelacteal feeds. In the multivariable analysis, mothers who had caesarean section delivery had 2·25 times the odds of giving prelacteal feeds compared with mothers who had spontaneous vaginal delivery (adjusted OR=2·25; 95 % CI 2·06, 2·46). Other factors that were significantly associated with increased likelihood of PLF were mother's lower educational status, first birth rank, fourth or above birth rank with preceding birth interval less than or equal to 24 months, lower number of antenatal care visits, home delivery, multiple birth, male infant, as well as having an average or small sized baby at birth. Mothers aged 20-34 years were less likely to give prelacteal feeds compared with mothers aged ≤19 years. Belonging to the second, middle or fourth wealth quintile was associated with lower likelihood of PLF compared with the highest quintile. To achieve optimal breast-feeding, there is a need to discourage breast-feeding practices such as PLF. Breast-feeding promotion programmes should target the at-risk sub-population groups discovered in our study.

Body weight concerns: Cross-national study and identification of factors related to eating disorders.

PubMed

Silva, Wanderson Roberto da; Santana, Moema de Souza; Maroco, João; Maloa, Benvindo Felismino Samuel; Campos, Juliana Alvares Duarte Bonini

2017-01-01

Body weight concerns are common among individuals with eating disorders, and this construct can be assessed using psychometric instruments. The Weight Concerns Scale (WCS) is commonly used to assess body weight concerns. To evaluate the psychometric properties of the WCS with Brazilian, Portuguese, and Mozambican female college students; to estimate body weight concerns; and to identify factors related to eating disorders. Confirmatory factor analysis was performed. Factorial, convergent, concurrent, and divergent validity, as well as reliability, were assessed. Cross-national invariance was tested by means of multigroup analysis. Structural models were tested using the WCS as the dependent variable, while demographic and academic variables and body mass index were used as independent variables. Logistic models were tested to estimate the likelihood of eating disorders being developed in specific groups. Participants were 2,068 female students. The psychometric properties of the WCS were adequate for the Portuguese sample; however, for the Brazilian and Mozambican samples, it was necessary to correlate the errors of two items to improve model fit. The WCS did not show cross-national invariance. The variables "thoughts about dropping out of college," "medication use because of studies," "medication and supplements use for body change," "body mass index," "socioeconomic status," "age," and "performance in course" were significant predictors of body weight concerns. Overall, 24.4% (95% confidence interval = 22.9-26.7) of the students were likely to develop eating disorders. Students under 21 years old, who use medication and supplements for body change, and who were classified as overweight/obese have increased likelihood of developing eating disorders. The WCS showed good psychometric properties with Brazilian, Portuguese, and Mozambican students; however, it did not show cross-national invariance. We identified important aspects for investigating body weight concerns and factors related to eating disorders.

The adaptive and maladaptive faces of dependency in later life: links to physical and psychological health outcomes.

PubMed

Fiori, Katherine; Consedine, Nathan; Magai, Carol

2008-11-01

Negotiating the balance between reliance on others and desires for autonomy is a fundamental task of successful aging. The purpose of the present study was to replicate and extend a three-factor model of interpersonal dependency in a sample of older adults, and to examine the physical and psychological health correlates of this multifaceted construct. Data come from the third wave of a population-based study of older Americans (n = 166; mean age 80 years). We conducted an exploratory factor analysis of selected dependency items from two scales, and then conducted logistic and hierarchical linear regressions to analyze the association of dependency factors with self-reported health, use of hypertension medication, depressed affect and positive affect. We found three factors closely paralleling those of Bornstein and Languirand's (Psychological Bulletin, 112(1), 3-23, 2004) measure: destructive overdependence, healthy dependency and dysfunctional detachment, as well as a fourth factor we labeled 'healthy independence'. Healthy dependency was associated with better self-reported health. Dysfunctional detachment was related to a greater likelihood and healthy independence a lesser likelihood of taking hypertension medication. Whereas both healthy independence and healthy dependency were positively related to positive affect and negatively related to depressed affect, destructive overdependence was positively related to depressed affect. Understanding the complex nature of interpersonal dependency and autonomy in old age, as well as their implications for health and wellbeing, may enable practitioners to assist older adults in negotiating the task of balancing these needs.

Factor analysis of the Foreign Language Classroom Anxiety Scale in Korean learners of English as a foreign language.

PubMed

Park, Gi-Pyo

2014-08-01

This study examined the latent constructs of the Foreign Language Classroom Anxiety Scale (FLCAS) using two different groups of Korean English as a foreign language (EFL) university students. Maximum likelihood exploratory factor analysis with direct oblimin rotation was performed among the first group of 217 participants and produced two meaningful latent components in the FLCAS. The two components of the FLCAS were closely examined among the second group of 244 participants to find the extent to which the two components of the FLCAS fit the data. The model fit indexes showed that the two-factor model in general adequately fit the data. Findings of this study were discussed with the focus on the two components of the FLCAS, followed by future study areas to be undertaken to shed further light on the role of foreign language anxiety in L2 acquisition.

Semiparametric time-to-event modeling in the presence of a latent progression event.

PubMed

Rice, John D; Tsodikov, Alex

2017-06-01

In cancer research, interest frequently centers on factors influencing a latent event that must precede a terminal event. In practice it is often impossible to observe the latent event precisely, making inference about this process difficult. To address this problem, we propose a joint model for the unobserved time to the latent and terminal events, with the two events linked by the baseline hazard. Covariates enter the model parametrically as linear combinations that multiply, respectively, the hazard for the latent event and the hazard for the terminal event conditional on the latent one. We derive the partial likelihood estimators for this problem assuming the latent event is observed, and propose a profile likelihood-based method for estimation when the latent event is unobserved. The baseline hazard in this case is estimated nonparametrically using the EM algorithm, which allows for closed-form Breslow-type estimators at each iteration, bringing improved computational efficiency and stability compared with maximizing the marginal likelihood directly. We present simulation studies to illustrate the finite-sample properties of the method; its use in practice is demonstrated in the analysis of a prostate cancer data set. © 2016, The International Biometric Society.

Likelihood to Use Employee Assistance Programs: The Effects of Sociodemographic, Social-Psychological, Sociocultural, Organizational, and Community Factors.

ERIC Educational Resources Information Center

Hall, LaCheata, And Others

1991-01-01

Employees (n=62) from large telephone communications company completed questionnaires assessing relationship between likelihood to use Employee Assistance Program (EAP) services and five domains: sociodemographic, social-psychological, sociocultural, organizational, and community. Found that women and individuals in higher income and educational…

A quasi-likelihood approach to non-negative matrix factorization

PubMed Central

Devarajan, Karthik; Cheung, Vincent C.K.

2017-01-01

A unified approach to non-negative matrix factorization based on the theory of generalized linear models is proposed. This approach embeds a variety of statistical models, including the exponential family, within a single theoretical framework and provides a unified view of such factorizations from the perspective of quasi-likelihood. Using this framework, a family of algorithms for handling signal-dependent noise is developed and its convergence proven using the Expectation-Maximization algorithm. In addition, a measure to evaluate the goodness-of-fit of the resulting factorization is described. The proposed methods allow modeling of non-linear effects via appropriate link functions and are illustrated using an application in biomedical signal processing. PMID:27348511

PAMLX: a graphical user interface for PAML.

PubMed

Xu, Bo; Yang, Ziheng

2013-12-01

This note announces pamlX, a graphical user interface/front end for the paml (for Phylogenetic Analysis by Maximum Likelihood) program package (Yang Z. 1997. PAML: a program package for phylogenetic analysis by maximum likelihood. Comput Appl Biosci. 13:555-556; Yang Z. 2007. PAML 4: Phylogenetic analysis by maximum likelihood. Mol Biol Evol. 24:1586-1591). pamlX is written in C++ using the Qt library and communicates with paml programs through files. It can be used to create, edit, and print control files for paml programs and to launch paml runs. The interface is available for free download at http://abacus.gene.ucl.ac.uk/software/paml.html.

Acculturation, education, nutrition education, and household composition are related to dietary practices among Cambodian refugee women in Lowell, MA.

PubMed

Peterman, Jerusha Nelson; Silka, Linda; Bermudez, Odilia I; Wilde, Parke E; Rogers, Beatrice Lorge

2011-09-01

Refugees in the United States have higher rates of some chronic diseases than US-born residents or other first-generation immigrants. This may be partially a result of dietary practices in the United States. There is limited information about which factors are related to dietary practices in refugee populations, particularly those who have been in the United States for 10 to 20 years. Research with Cambodian communities may be useful for examining the relationship between refugee characteristics and dietary practices. Two focus groups (n=11) and a survey (n=150) of Cambodian refugee women were conducted in Lowell, MA, from 2007 to 2008. χ(2) analyses, t tests, and analysis of variance tests were used to describe differences in dietary practices (24-hour recall and a targeted qualitative food assessment) by group characteristics. Higher acculturation was related to higher likelihood of eating brown rice/whole grains, and to lower likelihood of eating high-sodium Asian sauces. Higher education was related to higher likelihood of eating vegetables and fruits and to eating white rice fewer times. Nutrition education and receiving dietary advice from a health care provider were related to higher likelihood of eating whole grains/brown rice. Having a child at home was related to a higher likelihood of eating fast food. Among Cambodian refugees who have been in the United States for 10 to 20 years, dietary practices appear to have a relationship with acculturation (positive association), the interrupted education common to refugees (negative association), nutrition education from either programs or health care providers (positive association), and having a child at home (negative association). Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

Crossing the Threshold From Porn Use to Porn Problem: Frequency and Modality of Porn Use as Predictors of Sexually Coercive Behaviors.

PubMed

Marshall, Ethan A; Miller, Holly A; Bouffard, Jeff A

2017-11-01

According to recent statistics, as many as one in five female college students are victims of sexual assault during their college career. To combat what has been called the "Campus Rape Crisis," researchers have attempted to understand what variables are associated with sexually coercive behaviors in college males. Although investigators have found support for the relationship between pornography consumption and sexually coercive behavior, researchers typically operationalize pornography use in terms of frequency of use. Furthermore, frequency of use has been assessed vaguely and inconsistently. The current study offered a more concrete assessment of frequency of use and an additional variable not yet included for pornography use: number of modalities. Beyond examining the relationship between pornography use and sexual coercion likelihood, the current study was the first to use pornography variables in a threshold analysis to test whether there is a cut point that is predictive of sexual coercion likelihood. Analyses were conducted with a sample of 463 college males. Results indicated that both pornography use variables were significantly related to a higher likelihood of sexually coercive behaviors. When both frequency of use and number of modalities were included in the model, modalities were significant and frequency was not. In addition, significant thresholds for both pornography variables that predicted sexual coercion likelihood were identified. These results imply that factors other than frequency of use, such as number of modalities, may be more important for the prediction of sexual coercive behaviors. Furthermore, threshold analyses revealed the most significant increase in risk occurred between one modality and two, indicating that it is not pornography use in general that is related to sexual coercion likelihood, but rather, specific aspects of pornography use.

A Bayesian modelling framework for tornado occurrences in North America

NASA Astrophysics Data System (ADS)

Cheng, Vincent Y. S.; Arhonditsis, George B.; Sills, David M. L.; Gough, William A.; Auld, Heather

2015-03-01

Tornadoes represent one of nature’s most hazardous phenomena that have been responsible for significant destruction and devastating fatalities. Here we present a Bayesian modelling approach for elucidating the spatiotemporal patterns of tornado activity in North America. Our analysis shows a significant increase in the Canadian Prairies and the Northern Great Plains during the summer, indicating a clear transition of tornado activity from the United States to Canada. The linkage between monthly-averaged atmospheric variables and likelihood of tornado events is characterized by distinct seasonality; the convective available potential energy is the predominant factor in the summer; vertical wind shear appears to have a strong signature primarily in the winter and secondarily in the summer; and storm relative environmental helicity is most influential in the spring. The present probabilistic mapping can be used to draw inference on the likelihood of tornado occurrence in any location in North America within a selected time period of the year.

A Bayesian modelling framework for tornado occurrences in North America.

PubMed

Cheng, Vincent Y S; Arhonditsis, George B; Sills, David M L; Gough, William A; Auld, Heather

2015-03-25

Tornadoes represent one of nature's most hazardous phenomena that have been responsible for significant destruction and devastating fatalities. Here we present a Bayesian modelling approach for elucidating the spatiotemporal patterns of tornado activity in North America. Our analysis shows a significant increase in the Canadian Prairies and the Northern Great Plains during the summer, indicating a clear transition of tornado activity from the United States to Canada. The linkage between monthly-averaged atmospheric variables and likelihood of tornado events is characterized by distinct seasonality; the convective available potential energy is the predominant factor in the summer; vertical wind shear appears to have a strong signature primarily in the winter and secondarily in the summer; and storm relative environmental helicity is most influential in the spring. The present probabilistic mapping can be used to draw inference on the likelihood of tornado occurrence in any location in North America within a selected time period of the year.

Trajectories of Marital Conflict Across the Life Course: Predictors and Interactions With Marital Happiness Trajectories

PubMed Central

Kamp Dush, Claire M.; Taylor, Miles G.

2011-01-01

Using typologies outlined by Gottman and Fitzpatrick as well as institutional and companionate models of marriage, the authors conducted a latent class analysis of marital conflict trajectories using 20 years of data from the Marital Instability Over the Life Course study. Respondents were in one of three groups: high, medium (around the mean), or low conflict. Several factors predicted conflict trajectory group membership; respondents who believed in lifelong marriage and shared decisions equally with their spouse were more likely to report low and less likely to report high conflict. The conflict trajectories were intersected with marital happiness trajectories to examine predictors of high and low quality marriages. A stronger belief in lifelong marriage, shared decision making, and husbands sharing a greater proportion of housework were associated with an increased likelihood of membership in a high happiness, low conflict marriage, and a decreased likelihood of a low marital happiness group. PMID:22328798

Gender and Relationship Status Interaction and Likelihood of Return to Work Post-Retirement.

PubMed

Settels, Jason; McMullin, Julie

2017-09-01

Population aging is an issue of mounting importance throughout the industrialized world. Concerns over labour force shortages have led to policies that prolong working life. Accordingly, present-day workforce participation patterns of older individuals are extensively varied. This study utilized the 2007 General Social Survey to examine factors associated with post-retirement paid work, focusing on the interaction between gender and relationship status, among Canadians aged 50 to 74 who had retired at least once. We find that although being in a relationship is associated with a higher likelihood of post-retirement work for men, the opposite is true for women. Our findings suggest that the gendered association between relationship status and post-retirement work results partly from the gendered associations between relationship status and one's motivation for learning and community involvement, career orientation, and sense of independence. Gendered meanings of relationship status are thus revealed through analysis of post-retirement work.

Efficient Maximum Likelihood Estimation for Pedigree Data with the Sum-Product Algorithm.

PubMed

Engelhardt, Alexander; Rieger, Anna; Tresch, Achim; Mansmann, Ulrich

2016-01-01

We analyze data sets consisting of pedigrees with age at onset of colorectal cancer (CRC) as phenotype. The occurrence of familial clusters of CRC suggests the existence of a latent, inheritable risk factor. We aimed to compute the probability of a family possessing this risk factor as well as the hazard rate increase for these risk factor carriers. Due to the inheritability of this risk factor, the estimation necessitates a costly marginalization of the likelihood. We propose an improved EM algorithm by applying factor graphs and the sum-product algorithm in the E-step. This reduces the computational complexity from exponential to linear in the number of family members. Our algorithm is as precise as a direct likelihood maximization in a simulation study and a real family study on CRC risk. For 250 simulated families of size 19 and 21, the runtime of our algorithm is faster by a factor of 4 and 29, respectively. On the largest family (23 members) in the real data, our algorithm is 6 times faster. We introduce a flexible and runtime-efficient tool for statistical inference in biomedical event data with latent variables that opens the door for advanced analyses of pedigree data. © 2017 S. Karger AG, Basel.

Washing when the sun is shining! How users interact with a household energy management system.

PubMed

Kobus, Charlotte B A; Mugge, Ruth; Schoormans, Jan P L

2013-01-01

To make optimal use of sustainable energy, domestic electricity consumption should shift to match local supply conditions. Energy management systems (EMS) are a new sustainable technology that can help to disrupt consumers' habits concerning electricity consumption, whilst reinforcing desired behaviours. This research examined the factors that influence the likelihood that people will shift their electricity consumption to match sustainable supply. Twenty-one interviews were conducted with households who had used the EMS 'Smart Wash' for several months. The findings showed that the likelihood of behaviour change is influenced by a combination of the user's motivation, specific contextual factors and the design of the EMS. Based on these results, several recommendations are given for the future design of EMSs. Energy management systems (EMS) are a new technology that encourages people to shift electricity consumption to match local solar supply. Interviews among users of an EMS showed that the likelihood of behaviour change is influenced by the combination of the user's motivation, contextual factors and the EMS design.

Factors affecting receipt of chemotherapy in women with breast cancer

PubMed Central

Morimoto, Libby; Coalson, Jenna; Mowat, Fionna; O’Malley, Cynthia

2010-01-01

Aims: To review literature describing factors associated with receipt of chemotherapy for breast cancer, to better understand what factors are most relevant to women’s health and whether health disparities are apparent, and to assess how these factors might affect observational studies and outcomes research. Patterns of care for metastatic breast cancer, for which no standard-of-care exists, were of particular interest. Methods: Relevant studies written in English, Italian, French, or Spanish, published in 2000 or later, were identified through MEDLINE and reviewed. Review articles and clinical trials were excluded; all observational studies and surveys were considered. Articles were reviewed for any discussion of patient characteristics, hospital/physician/insurance characteristics, psychosocial characteristics, and clinical characteristics affecting receipt of chemotherapy by breast cancer patients. Results: In general, factors associated with increased likelihood of receiving chemotherapy included younger age, being Caucasian, having good general health and few co-morbidities, having more severe clinical disease, having responded well to previous treatment, and having breast cancer that is estrogen- or progesterone-receptor-negative. Many of the clinical factors found to increase the likelihood of receiving chemotherapy were consistent with current oncology guidelines. Of the relevant 19 studies identified, only six (32%) reported data specific to metastatic cancer; most studies aggregated women with stage I–IV for purposes of analysis. Conclusion: Studies of patterns of care in breast cancer treatment can help identify challenges in health care provided to particular subgroups of women and can aid researchers in designing studies that account for such factors in clinical and outcomes research. Although scarce, studies evaluating only women with metastatic breast cancer indicate that factors affecting decisions related to receipt of chemotherapy are similar across stage for this disease. PMID:21072304

Psychometric evaluation of the thought-action fusion scale in a large clinical sample.

PubMed

Meyer, Joseph F; Brown, Timothy A

2013-12-01

This study examined the psychometric properties of the 19-item Thought-Action Fusion (TAF) Scale, a measure of maladaptive cognitive intrusions, in a large clinical sample (N = 700). An exploratory factor analysis (n = 300) yielded two interpretable factors: TAF Moral (TAF-M) and TAF Likelihood (TAF-L). A confirmatory bifactor analysis was conducted on the second portion of the sample (n = 400) to account for possible sources of item covariance using a general TAF factor (subsuming TAF-M) alongside the TAF-L domain-specific factor. The bifactor model provided an acceptable fit to the sample data. Results indicated that global TAF was more strongly associated with a measure of obsessive-compulsiveness than measures of general worry and depression, and the TAF-L dimension was more strongly related to obsessive-compulsiveness than depression. Overall, results support the bifactor structure of the TAF in a clinical sample and its close relationship to its neighboring obsessive-compulsiveness construct.

Psychometric Evaluation of the Thought–Action Fusion Scale in a Large Clinical Sample

PubMed Central

Meyer, Joseph F.; Brown, Timothy A.

2015-01-01

This study examined the psychometric properties of the 19-item Thought–Action Fusion (TAF) Scale, a measure of maladaptive cognitive intrusions, in a large clinical sample (N = 700). An exploratory factor analysis (n = 300) yielded two interpretable factors: TAF Moral (TAF-M) and TAF Likelihood (TAF-L). A confirmatory bifactor analysis was conducted on the second portion of the sample (n = 400) to account for possible sources of item covariance using a general TAF factor (subsuming TAF-M) alongside the TAF-L domain-specific factor. The bifactor model provided an acceptable fit to the sample data. Results indicated that global TAF was more strongly associated with a measure of obsessive-compulsiveness than measures of general worry and depression, and the TAF-L dimension was more strongly related to obsessive-compulsiveness than depression. Overall, results support the bifactor structure of the TAF in a clinical sample and its close relationship to its neighboring obsessive-compulsiveness construct. PMID:22315482

Robust Multipoint Water-Fat Separation Using Fat Likelihood Analysis

PubMed Central

Yu, Huanzhou; Reeder, Scott B.; Shimakawa, Ann; McKenzie, Charles A.; Brittain, Jean H.

2016-01-01

Fat suppression is an essential part of routine MRI scanning. Multiecho chemical-shift based water-fat separation methods estimate and correct for Bo field inhomogeneity. However, they must contend with the intrinsic challenge of water-fat ambiguity that can result in water-fat swapping. This problem arises because the signals from two chemical species, when both are modeled as a single discrete spectral peak, may appear indistinguishable in the presence of Bo off-resonance. In conventional methods, the water-fat ambiguity is typically removed by enforcing field map smoothness using region growing based algorithms. In reality, the fat spectrum has multiple spectral peaks. Using this spectral complexity, we introduce a novel concept that identifies water and fat for multiecho acquisitions by exploiting the spectral differences between water and fat. A fat likelihood map is produced to indicate if a pixel is likely to be water-dominant or fat-dominant by comparing the fitting residuals of two different signal models. The fat likelihood analysis and field map smoothness provide complementary information, and we designed an algorithm (Fat Likelihood Analysis for Multiecho Signals) to exploit both mechanisms. It is demonstrated in a wide variety of data that the Fat Likelihood Analysis for Multiecho Signals algorithm offers highly robust water-fat separation for 6-echo acquisitions, particularly in some previously challenging applications. PMID:21842498

The association between price, competition, and demand factors on private sector anti-malarial stocking and sales in western Kenya: considerations for the AMFm subsidy.

PubMed

O'Meara, Wendy Prudhomme; Obala, Andrew; Thirumurthy, Harsha; Khwa-Otsyula, Barasa

2013-06-05

Households in sub-Saharan Africa are highly reliant on the retail sector for obtaining treatment for malaria fevers and other illnesses. As donors and governments seek to promote the use of artemisinin combination therapy in malaria-endemic areas through subsidized anti-malarials offered in the retail sector, understanding the stocking and pricing decisions of retail outlets is vital. A survey of all medicine retailers serving Bungoma East District in western Kenya was conducted three months after the launch of the AMFm subsidy in Kenya. The survey obtained information on each anti-malarial in stock: brand name, price, sales volume, outlet characteristics and GPS co-ordinates. These data were matched to household-level data from the Webuye Health and Demographic Surveillance System, from which population density and fever prevalence near each shop were determined. Regression analysis was used to identify the factors associated with retailers' likelihood of stocking subsidized artemether lumefantrine (AL) and the association between price and sales for AL, quinine and sulphadoxine-pyrimethamine (SP). Ninety-seven retail outlets in the study area were surveyed; 11% of outlets stocked subsidized AL. Size of the outlet and having a pharmacist on staff were associated with greater likelihood of stocking subsidized AL. In the multivariable model, total volume of anti-malarial sales was associated with greater likelihood of stocking subsidized AL and competition was important; likelihood of stocking subsidized AL was considerably higher if the nearest neighbour stocked subsidized AL. Price was a significant predictor of sales volume for all three types of anti-malarials but the relationship varied, with the largest price sensitivity found for SP drugs. The results suggest that helping small outlets overcome the constraints to stocking subsidized AL should be a priority. Competition between retailers and prices can play an important role in greater adoption of AL.

Use pattern and predictors of use of highly caffeinated energy drinks among South Korean adolescents: a study using the Health Belief Model

PubMed Central

Ha, Dongmun; Song, Inmyung; Jang, Gyeongil; Lee, Eui-Kyung; Shin, Ju-Young

2017-01-01

Objectives Concerns about the use of highly caffeinated energy drinks among Korean adolescents remains. We compared adolescents’ perceptions regarding the use of drinks to their behaviours and factors. Design A structured questionnaire based on the Health Belief Model was administered to 850 freshmen and sophomores at three high schools in Bucheon, South Korea. Benefits were defined as beneficial effects from the use of highly caffeinated energy drinks (eg, awakening from sleepiness) and harms as adverse effects of the drinks (eg, cardiac palpitation). Likelihood of action represents the likelihood of taking actions that are perceived to be more beneficial after comparison of the benefits and harms of caffeine use. Descriptive analysis was used to quantify the relationship between their beliefs about highly caffeinated energy drinks and their use. We conducted hierarchical logistic regression to compute ORs and 95% CIs for: (1) demographic factors, (2) health threat, (3) likelihood of action and (4) cues to act. Results Altogether, 833 students responded to the questionnaire (effective response rate=98.0%). About 63.0% reported use of highly caffeinated energy drinks and 35.2% had used them as needed and habitually. The more susceptible the respondents perceived themselves to be to the risk of using these drinks, the less likely they were to use them (OR: 0.73, 95% CI 0.50 to 1.06). The more severe the perception of a health threat, the less that perception was associated with use (OR: 0.44, 95% CI 0.29 to 0.67). Likelihood of action was the strongest predictor of use, explaining 12.5% in use. Benefits and harms (OR: 4.43, 95% CI 2.77 to 7.09; OR: 1.86, 95% CI 1.16 to 2.99) also were significant predictors. Conclusions Enhancing adolescents’ perceptions of benefits and harms regarding using highly caffeinated energy drinks could be an effective way to influence the use of these drinks. PMID:28947455

The association between price, competition, and demand factors on private sector anti-malarial stocking and sales in western Kenya: considerations for the AMFm subsidy

PubMed Central

2013-01-01

Background Households in sub-Saharan Africa are highly reliant on the retail sector for obtaining treatment for malaria fevers and other illnesses. As donors and governments seek to promote the use of artemisinin combination therapy in malaria-endemic areas through subsidized anti-malarials offered in the retail sector, understanding the stocking and pricing decisions of retail outlets is vital. Methods A survey of all medicine retailers serving Bungoma East District in western Kenya was conducted three months after the launch of the AMFm subsidy in Kenya. The survey obtained information on each anti-malarial in stock: brand name, price, sales volume, outlet characteristics and GPS co-ordinates. These data were matched to household-level data from the Webuye Health and Demographic Surveillance System, from which population density and fever prevalence near each shop were determined. Regression analysis was used to identify the factors associated with retailers’ likelihood of stocking subsidized artemether lumefantrine (AL) and the association between price and sales for AL, quinine and sulphadoxine-pyrimethamine (SP). Results Ninety-seven retail outlets in the study area were surveyed; 11% of outlets stocked subsidized AL. Size of the outlet and having a pharmacist on staff were associated with greater likelihood of stocking subsidized AL. In the multivariable model, total volume of anti-malarial sales was associated with greater likelihood of stocking subsidized AL and competition was important; likelihood of stocking subsidized AL was considerably higher if the nearest neighbour stocked subsidized AL. Price was a significant predictor of sales volume for all three types of anti-malarials but the relationship varied, with the largest price sensitivity found for SP drugs. Conclusion The results suggest that helping small outlets overcome the constraints to stocking subsidized AL should be a priority. Competition between retailers and prices can play an important role in greater adoption of AL. PMID:23738604

Human factors evaluation of remote afterloading brachytherapy. Volume 2, Function and task analysis

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

Callan, J.R.; Gwynne, J.W. III; Kelly, T.T.

1995-05-01

A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the first phase of the project, which involved an extensive function and task analysis of RAB. This analysis identified the functions and tasks in RAB, made preliminary estimates of the likelihood of human error in each task, and determined the skills needed to perform each RAB task.more » The findings of the function and task analysis served as the foundation for the remainder of the project, which evaluated four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training and qualifications of RAB staff; and organizational practices and policies. At its completion, the project identified and prioritized areas for recommended NRC and industry attention based on all of the evaluations and analyses.« less

CT Texture Analysis of Ex Vivo Renal Stones Predicts Ease of Fragmentation with Shockwave Lithotripsy.

PubMed

Cui, Helen W; Devlies, Wout; Ravenscroft, Samuel; Heers, Hendrik; Freidin, Andrew J; Cleveland, Robin O; Ganeshan, Balaji; Turney, Benjamin W

2017-07-01

Understanding the factors affecting success of extracorporeal shockwave lithotripsy (SWL) would improve informed decision-making on the most appropriate treatment modality for an individual patient. Although stone size and skin-to-stone distance do correlate with fragmentation efficacy, it has been shown that stone composition and architecture, as reflected by structural heterogeneity on CT, are also important factors. This study aims to determine if CT texture analysis (CTTA), a novel, nondestructive, and objective tool that generates statistical metrics reflecting stone heterogeneity, could have utility in predicting likelihood of SWL success. Seven spontaneously passed, intact renal tract stones, were scanned ex vivo using standard CT KUB and micro-CT. The stones were then fragmented in vitro using a clinical lithotripter, after which, chemical composition analysis was performed. CTTA was used to generate a number of metrics that were correlated to the number of shocks needed to fragment the stone. CTTA metrics reflected stone characteristics and composition, and predicted ease of SWL fragmentation. The strongest correlation with number of shocks required to fragment the stone was mean Hounsfield unit (HU) density (r = 0.806, p = 0.028) and a CTTA metric measuring the entropy of the pixel distribution of the stone image (r = 0.804, p = 0.039). Using multiple linear regression analysis, the best model showed that CTTA metrics of entropy and kurtosis could predict 92% of the outcome of number of shocks needed to fragment the stone. This was superior to using stone volume or density. CTTA metrics entropy and kurtosis have been shown in this experimental ex vivo setting to strongly predict fragmentation by SWL. This warrants further investigation in a larger clinical study for the contribution of CT textural metrics as a measure of stone heterogeneity, along with other known clinical factors, to predict likelihood of SWL success.

Causation or selection - examining the relation between education and overweight/obesity in prospective observational studies: a meta-analysis.

PubMed

Kim, T J; Roesler, N M; von dem Knesebeck, O

2017-06-01

Numerous studies have investigated the association between education and overweight/obesity. Yet less is known about the relative importance of causation (i.e. the influence of education on risks of overweight/obesity) and selection (i.e. the influence of overweight/obesity on the likelihood to attain education) hypotheses. A systematic review was performed to assess the linkage between education and overweight/obesity in prospective studies in general populations. Studies were searched within five databases, and study quality was appraised with the Newcastle-Ottawa scale. In total, 31 studies were considered for meta-analysis. Regarding causation (24 studies), the lower educated had a higher likelihood (odds ratio: 1.33, 1.21-1.47) and greater risk (risk ratio: 1.34, 1.08-1.66) for overweight/obesity, when compared with the higher educated. However, these associations were no longer statistically significant when accounting for publication bias. Concerning selection (seven studies), overweight/obese individuals had a greater likelihood of lower education (odds ratio: 1.57, 1.10-2.25), when contrasted with the non-overweight or non-obese. Subgroup analyses were performed by stratifying meta-analyses upon different factors. Relationships between education and overweight/obesity were affected by study region, age groups, gender and observation period. In conclusion, it is necessary to consider both causation and selection processes in order to tackle educational inequalities in obesity appropriately. © 2017 World Obesity Federation.

Looks and linguistics: Impression formation in online exchange marketplaces.

PubMed

Ciuchta, Michael P; O'Toole, Jay

2016-01-01

This study advances theories of impression formation by focusing on two factors that generate emotional responses: physical attractiveness and positive word use. Although considerable research on impression formation exists, most studies consider factors in isolation and neglect possible interactions. Our theory introduces competing mechanisms regarding possible interaction effects, and we empirically test them in an online marketplace. Results from the analysis of 729 loan requests from a leading online peer-to-peer lending market suggest that physical attractiveness and positive word use work together to influence the likelihood of acquiring resources and establish an important boundary condition to the general "beauty is good" effect.

International Sexual Partnerships May Be Shaped by Sexual Histories and Socioeconomic Status.

PubMed

Truong, Hong-Ha M; Mehrotra, Megha; Montoya, Orlando; Lama, Javier R; Guanira, Juan V; Casapía, Martín; Veloso, Valdiléa G; Buchbinder, Susan P; Mayer, Kenneth H; Chariyalertsak, Suwat; Schechter, Mauro; Bekker, Linda-Gail; Kallás, Esper G; Grant, Robert M

2017-05-01

Exchange sex and higher education were associated with an increased likelihood of international sexual partnerships (ISPs). Exchange sex and older age were associated with an increased likelihood of condomless sex in ISPs. Educational and socioeconomic factors may create unbalanced power dynamics that influence exchange sex and condomless sex in ISPs.

Factors associated with the enactment of safety belt and motorcycle helmet laws.

PubMed

Law, Teik Hua; Noland, Robert B; Evans, Andrew W

2013-07-01

It has been shown that road safety laws, such as motorcycle helmet and safety belt laws, have a significant effect in reducing road fatalities. Although an expanding body of literature has documented the effects of these laws on road safety, it remains unclear which factors influence the likelihood that these laws are enacted. This study attempts to identify the factors that influence the decision to enact safety belt and motorcycle helmet laws. Using panel data from 31 countries between 1963 and 2002, our results reveal that increased democracy, education level, per capita income, political stability, and more equitable income distribution within a country are associated with the enactment of road safety laws. © 2012 Society for Risk Analysis.

Organisational change, job strain and increased risk of stroke? A pilot study.

PubMed

Medin, Jennie; Ekberg, Kerstin; Nordlund, Anders; Eklund, Jörgen

2008-01-01

The objective of this pilot study was to explore whether organisational change and work-related stress, as measured by the Job Content Questionnaire, were associated with first-ever stroke among working people aged 30-65. In a case-control study a total of 65 consecutive cases, aged 30-65 years of age, with first-ever stroke were recruited from four hospitals in Sweden during 2000-2002. During the same period, 103 random population controls in the same age interval were recruited. Data on job-related stress and traditional medical risk factors were collected by a questionnaire. In the multivariate analyses, organisational change (OR 3.38) increased the likelihood of stroke, while experiencing an active job (OR 0.37) decreased the likelihood of stroke. Regarding risk factors outside work, age (OR 1.11), low physical activity (OR 5.21), low education (OR 2.48) and family history of stroke (OR 2.59) were associated with increased likelihood of stroke. This study suggests an association between organisational change, work-related stress and stroke. The likelihood of stroke was lower for people in active job situations.

Factors Influencing Patient Experience in Pediatric Neurology.

PubMed

Singh, Suprit C; Sheth, Raj D; Burrows, James F; Rosen, Paul

2016-07-01

Hospitals have begun to shift toward patient-centered care because of the pay-for-performance system that was established by the Patient Protection and Affordable Care Act. In pediatrics, the needs of both the caregiver and the pediatric patient have to be taken into account. Pediatric practices have been shifting toward a family-centered approach, although the primary drivers have not been well defined. Identifying the key patient experiences that lead to higher patient satisfaction would enable a more meaningful clinical encounter. To better understand patient experience, we examined waiting time and the elements of the physician-patient interaction in pediatric neurology. We predict that the determining factor in patient satisfaction is the physician-patient interaction. Patient satisfaction surveys were sent to families via mail or e-mail after their ambulatory pediatric neurology visit. The visits took place between January 1, 2012, and December 31, 2014, at one of multiple locations in a children's health system spanning four states. A Likert scale was used for these surveys, and a top-box method (measuring percent of survey questions were rated 5 out of 5) was used to filter data from this database. Statistical analysis using a Pearson correlation was used for data analysis, with likelihood to recommend practice as the dependent variable. The five survey questions that correlated most with overall likelihood to recommend the practice were cheerfulness of practice (r = 0.79); staff working together (r = 0.76); cleanliness of practice (r = 0.70); wait time at clinic, from entering to leaving (r = 0.66); and likelihood of recommending care provider (r = 0.65). Pediatric neurologists striving to enhance overall patient satisfaction in their practices should work toward providing an atmosphere that supports office staff cheerfulness, teamwork, and visit efficiency provided in a clean and friendly environment. Copyright © 2016 Elsevier Inc. All rights reserved.

Symptomatic treatment in multiple sclerosis-interim analysis of a nationwide registry.

PubMed

Skierlo, S; Rommer, P S; Zettl, U K

2017-04-01

To analyze symptomatic treatment in patients with multiple sclerosis (MS). Multiple sclerosis is a chronic inflammatory disease of the central nervous system, with accumulating disability symptoms like spasticity, voiding disorders, depression, and pain might occur. The nationwide German MS registry was initiated 2001 under guidance of the German MS society (Deutsche MS Gesellschaft). This study was performed as an interim analysis to lay foundation for future work on this topic. A subcohort of 5113 patients was assessed for this interim analysis. The mean age of the patients was 45.3 years; mean EDSS was 4.2. More than two-third of the enrolled patients were females (70.9%). Most frequent symptoms were fatigue (60%), followed by spasticity (52.5%) and voiding disorders (51.7%). The likelihood of treatment was highest for epileptic disorders (68.8%), spasticity (68.5%), pain (60.7%), and depression (58.9%). Multivariate regression analysis showed that retirement was the strongest factor predictive for antispastic treatment (β=.061, P=.005). Almost all patients in this analysis suffer from symptoms due to advanced MS. Treatment for the various symptoms differed tremendously. The likelihood of treatment correlated with the availability of effective therapeutic agents. Clinicians should put more awareness on MS symptoms. Symptomatic treatment may improve quality of life. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Massive optimal data compression and density estimation for scalable, likelihood-free inference in cosmology

NASA Astrophysics Data System (ADS)

Alsing, Justin; Wandelt, Benjamin; Feeney, Stephen

2018-07-01

Many statistical models in cosmology can be simulated forwards but have intractable likelihood functions. Likelihood-free inference methods allow us to perform Bayesian inference from these models using only forward simulations, free from any likelihood assumptions or approximations. Likelihood-free inference generically involves simulating mock data and comparing to the observed data; this comparison in data space suffers from the curse of dimensionality and requires compression of the data to a small number of summary statistics to be tractable. In this paper, we use massive asymptotically optimal data compression to reduce the dimensionality of the data space to just one number per parameter, providing a natural and optimal framework for summary statistic choice for likelihood-free inference. Secondly, we present the first cosmological application of Density Estimation Likelihood-Free Inference (DELFI), which learns a parametrized model for joint distribution of data and parameters, yielding both the parameter posterior and the model evidence. This approach is conceptually simple, requires less tuning than traditional Approximate Bayesian Computation approaches to likelihood-free inference and can give high-fidelity posteriors from orders of magnitude fewer forward simulations. As an additional bonus, it enables parameter inference and Bayesian model comparison simultaneously. We demonstrate DELFI with massive data compression on an analysis of the joint light-curve analysis supernova data, as a simple validation case study. We show that high-fidelity posterior inference is possible for full-scale cosmological data analyses with as few as ˜104 simulations, with substantial scope for further improvement, demonstrating the scalability of likelihood-free inference to large and complex cosmological data sets.

Effect of radiance-to-reflectance transformation and atmosphere removal on maximum likelihood classification accuracy of high-dimensional remote sensing data

NASA Technical Reports Server (NTRS)

Hoffbeck, Joseph P.; Landgrebe, David A.

1994-01-01

Many analysis algorithms for high-dimensional remote sensing data require that the remotely sensed radiance spectra be transformed to approximate reflectance to allow comparison with a library of laboratory reflectance spectra. In maximum likelihood classification, however, the remotely sensed spectra are compared to training samples, thus a transformation to reflectance may or may not be helpful. The effect of several radiance-to-reflectance transformations on maximum likelihood classification accuracy is investigated in this paper. We show that the empirical line approach, LOWTRAN7, flat-field correction, single spectrum method, and internal average reflectance are all non-singular affine transformations, and that non-singular affine transformations have no effect on discriminant analysis feature extraction and maximum likelihood classification accuracy. (An affine transformation is a linear transformation with an optional offset.) Since the Atmosphere Removal Program (ATREM) and the log residue method are not affine transformations, experiments with Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were conducted to determine the effect of these transformations on maximum likelihood classification accuracy. The average classification accuracy of the data transformed by ATREM and the log residue method was slightly less than the accuracy of the original radiance data. Since the radiance-to-reflectance transformations allow direct comparison of remotely sensed spectra with laboratory reflectance spectra, they can be quite useful in labeling the training samples required by maximum likelihood classification, but these transformations have only a slight effect or no effect at all on discriminant analysis and maximum likelihood classification accuracy.

Risk factors associated with detailed reproductive phenotypes in dairy and beef cows.

PubMed

Carthy, T R; Berry, D P; Fitzgerald, A; McParland, S; Williams, E J; Butler, S T; Cromie, A R; Ryan, D

2014-05-01

The objective of this study was to identify detailed fertility traits in dairy and beef cattle from transrectal ultrasonography records and quantify the associated risk factors. Data were available on 148 947 ultrasound observations of the reproductive tract from 75 949 cows in 843 Irish dairy and beef herds between March 2008 and October 2012. Traits generated included (1) cycling at time of examination, (2) cystic structures, (3) early ovulation, (4) embryo death and (5) uterine score; the latter was measured on a scale of 1 (good) to 4 (poor) characterising the tone of the uterine wall and fluid present in the uterus. After editing, 72,773 records from 44,415 dairy and beef cows in 643 herds remained. Factors associated with the logit of the probability of a positive outcome for each of the binary fertility traits were determined using generalised estimating equations; linear mixed model analysis was used for the analysis of uterine score. The prevalence of cycling, cystic structures, early ovulation and embryo death was 84.75%, 3.87%, 7.47% and 3.84%, respectively. The occurrence of the uterine heath score of 1, 2, 3 and 4 was 70.63%, 19.75%, 8.36% and 1.26%, respectively. Cows in beef herds had a 0.51 odds (95% CI=0.41 to 0.63, P<0.001) of cycling at the time of examination compared with cows in dairy herds; stage of lactation at the time of examination was the same in both herd types. Furthermore, cows in dairy herds had an inferior uterine score (indicating poorer tone and a greater quantity of uterine fluid present) compared with cows in beef herds. The likelihood of cycling at the time of examination increased with parity and stage of lactation, but was reduced in cows that had experienced dystocia in the previous calving. The presence of cystic structures on the ovaries increased with parity and stage of lactation. The likelihood of embryo/foetal death increased with parity and stage of lactation. Dystocia was not associated with the presence of cystic structures or embryo death. Uterine score improved with parity and stage of lactation, while cows that experienced dystocia in the previous calving had an inferior uterine score. Heterosis was the only factor associated with increased likelihood of early ovulation. The fertility traits identified, and the associated risk factors, provide useful information on the reproductive status of dairy and beef cows.

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: towards a computationally efficient analysis without informative priors

NASA Astrophysics Data System (ADS)

Pellejero-Ibanez, Marcos; Chuang, Chia-Hsun; Rubiño-Martín, J. A.; Cuesta, Antonio J.; Wang, Yuting; Zhao, Gongbo; Ross, Ashley J.; Rodríguez-Torres, Sergio; Prada, Francisco; Slosar, Anže; Vazquez, Jose A.; Alam, Shadab; Beutler, Florian; Eisenstein, Daniel J.; Gil-Marín, Héctor; Grieb, Jan Niklas; Ho, Shirley; Kitaura, Francisco-Shu; Percival, Will J.; Rossi, Graziano; Salazar-Albornoz, Salvador; Samushia, Lado; Sánchez, Ariel G.; Satpathy, Siddharth; Seo, Hee-Jong; Tinker, Jeremy L.; Tojeiro, Rita; Vargas-Magaña, Mariana; Brownstein, Joel R.; Nichol, Robert C.; Olmstead, Matthew D.

2017-07-01

We develop a new computationally efficient methodology called double-probe analysis with the aim of minimizing informative priors (those coming from extra probes) in the estimation of cosmological parameters. Using our new methodology, we extract the dark energy model-independent cosmological constraints from the joint data sets of the Baryon Oscillation Spectroscopic Survey (BOSS) galaxy sample and Planck cosmic microwave background (CMB) measurements. We measure the mean values and covariance matrix of {R, la, Ωbh2, ns, log(As), Ωk, H(z), DA(z), f(z)σ8(z)}, which give an efficient summary of the Planck data and two-point statistics from the BOSS galaxy sample. The CMB shift parameters are R=√{Ω _m H_0^2} r(z_*) and la = πr(z*)/rs(z*), where z* is the redshift at the last scattering surface, and r(z*) and rs(z*) denote our comoving distance to the z* and sound horizon at z*, respectively; Ωb is the baryon fraction at z = 0. This approximate methodology guarantees that we will not need to put informative priors on the cosmological parameters that galaxy clustering is unable to constrain, I.e. Ωbh2 and ns. The main advantage is that the computational time required for extracting these parameters is decreased by a factor of 60 with respect to exact full-likelihood analyses. The results obtained show no tension with the flat Λ cold dark matter (ΛCDM) cosmological paradigm. By comparing with the full-likelihood exact analysis with fixed dark energy models, on one hand we demonstrate that the double-probe method provides robust cosmological parameter constraints that can be conveniently used to study dark energy models, and on the other hand we provide a reliable set of measurements assuming dark energy models to be used, for example, in distance estimations. We extend our study to measure the sum of the neutrino mass using different methodologies, including double-probe analysis (introduced in this study), full-likelihood analysis and single-probe analysis. From full-likelihood analysis, we obtain Σmν < 0.12 (68 per cent), assuming ΛCDM and Σmν < 0.20 (68 per cent) assuming owCDM. We also find that there is degeneracy between observational systematics and neutrino masses, which suggests that one should take great care when estimating these parameters in the case of not having control over the systematics of a given sample.

Individual, team, and coach predictors of players' likelihood to aggress in youth soccer.

PubMed

Chow, Graig M; Murray, Kristen E; Feltz, Deborah L

2009-08-01

The purpose of this study was to examine personal and socioenvironmental factors of players' likelihood to aggress. Participants were youth soccer players (N = 258) and their coaches (N = 23) from high school and club teams. Players completed the Judgments About Moral Behavior in Youth Sports Questionnaire (JAMBYSQ; Stephens, Bredemeier, & Shields, 1997), which assessed athletes' stage of moral development, team norm for aggression, and self-described likelihood to aggress against an opponent. Coaches were administered the Coaching Efficacy Scale (CES; Feltz, Chase, Moritz, & Sullivan, 1999). Using multilevel modeling, results demonstrated that the team norm for aggression at the athlete and team level were significant predictors of athletes' self likelihood to aggress scores. Further, coaches' game strategy efficacy emerged as a positive predictor of their players' self-described likelihood to aggress. The findings contribute to previous research examining the socioenvironmental predictors of athletic aggression in youth sport by demonstrating the importance of coaching efficacy beliefs.

Minia, Egypt: Principal Component Analysis

PubMed

Abdelrehim, Marwa G; Mahfouz, Eman M; Ewis, Ashraf A; Seedhom, Amany E; Afifi, Hassan M; Shebl, Fatma M

2018-02-26

Background: Pancreatic cancer (PC) is a serious and rapidly progressing malignancy. Identifying risk factors including dietary elements is important to develop preventive strategies. This study focused on possible links between diet and PC. Methods: We conducted a case-control study including all PC patients diagnosed at Minia Cancer Center and controls from general population from June 2014 to December 2015. Dietary data were collected directly through personal interviews. Principal component analysis (PCA) was performed to identify dietary groups. The data were analyzed using crude odds ratios (ORs) and multivariable logistic regression with adjusted ORs and 95% confidence intervals (CIs). Results: A total of 75 cases and 149 controls were included in the study. PCA identified six dietary groups, labeled as cereals and grains, vegetables, proteins, dairy products, fruits, and sugars. Bivariate analysis showed that consumption of vegetables, fruits, sugars, and total energy intake were associated with change in PC risk. In multivariable-adjusted models comparing highest versus lowest levels of intake, we observed significant lower odds of PC in association with vegetable intake (OR 0.24; 95% CI, 0.07-0.85, P=0.012) and a higher likelihood with the total energy intake (OR 9.88; 95% CI, 2.56-38.09, P<0.0001). There was also a suggested link between high fruit consumption and reduced odds of PC. Conclusions: The study supports the association between dietary factors and the odds of PC development in Egypt. It was found that higher energy intake is associated with an increase in likelihood of PC, while increased vegetable consumption is associated with a lower odds ratio. Creative Commons Attribution License

A Social Ecology Analysis of Childbirth Among Females Emancipating From Foster Care.

PubMed

Shpiegel, Svetlana; Cascardi, Michele; Dineen, Michael

2017-05-01

No research has examined childbirth from a national perspective among females emancipating from foster care. The present study fills this gap by: (1) documenting the rates of initial and repeat births among females ages 17 and 19 in a national prospective study and (2) identifying risk and protective factors at age 17 that predict childbirth between ages 17 and 19. This study used data from the National Youth in Transition Database and Adoption and Foster Care Analysis and Reporting System to identify risk and protective factors associated with childbirth in a national sample of transition-age female youth (N = 3,474). The cumulative rate of childbirth by age 19 was 21%, with higher rates reported between ages 17 and 19 (17%; n = 602) compared with age 17 or earlier (9%; n = 313). In logistic regression analysis, black race and Hispanic ethnicity, placement with relatives, runaway status, trial home visit placement, early emancipation from foster care, and lifetime incarceration histories were associated with increased likelihood of childbirth. In contrast, school enrollment and employment skills were associated with decreased likelihood of childbirth. The multivariate odds of childbirth between ages 17 and 19 increased 10-fold if youth already had a child by age 17. Sexual health and pregnancy prevention programs should specifically target youths who already have children. Increased attention should be paid to adolescents placed with biological families and those with histories of criminal involvement. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Vocational Qualifications, Employment Status and Income: 2006 Census Analysis. Technical Paper

ERIC Educational Resources Information Center

Daly, Anne

2011-01-01

Two features of the labour market for vocationally qualified workers are explored in this technical paper: the likelihood of self-employment versus wage employment and the determinants of income. The analysis showed that demographic, occupational and local labour market characteristics all influence the likelihood of self-employment. Self-employed…

Maximum-likelihood methods in wavefront sensing: stochastic models and likelihood functions

PubMed Central

Barrett, Harrison H.; Dainty, Christopher; Lara, David

2008-01-01

Maximum-likelihood (ML) estimation in wavefront sensing requires careful attention to all noise sources and all factors that influence the sensor data. We present detailed probability density functions for the output of the image detector in a wavefront sensor, conditional not only on wavefront parameters but also on various nuisance parameters. Practical ways of dealing with nuisance parameters are described, and final expressions for likelihoods and Fisher information matrices are derived. The theory is illustrated by discussing Shack–Hartmann sensors, and computational requirements are discussed. Simulation results show that ML estimation can significantly increase the dynamic range of a Shack–Hartmann sensor with four detectors and that it can reduce the residual wavefront error when compared with traditional methods. PMID:17206255

Breakthrough seizures—Further analysis of the Standard versus New Antiepileptic Drugs (SANAD) study

PubMed Central

Powell, Graham A.; Tudur Smith, Catrin; Marson, Anthony G.

2017-01-01

Objectives To develop prognostic models for risk of a breakthrough seizure, risk of seizure recurrence after a breakthrough seizure, and likelihood of achieving 12-month remission following a breakthrough seizure. A breakthrough seizure is one that occurs following at least 12 months remission whilst on treatment. Methods We analysed data from the SANAD study. This long-term randomised trial compared treatments for participants with newly diagnosed epilepsy. Multivariable Cox models investigated how clinical factors affect the probability of each outcome. Best fitting multivariable models were produced with variable reduction by Akaike’s Information Criterion. Risks associated with combinations of risk factors were calculated from each multivariable model. Results Significant factors in the multivariable model for risk of a breakthrough seizure following 12-month remission were number of tonic-clonic seizures by achievement of 12-month remission, time taken to achieve 12-month remission, and neurological insult. Significant factors in the model for risk of seizure recurrence following a breakthrough seizure were total number of drugs attempted to achieve 12-month remission, time to achieve 12-month remission prior to breakthrough seizure, and breakthrough seizure treatment decision. Significant factors in the model for likelihood of achieving 12-month remission after a breakthrough seizure were gender, age at breakthrough seizure, time to achieve 12-month remission prior to breakthrough, and breakthrough seizure treatment decision. Conclusions This is the first analysis to consider risk of a breakthrough seizure and subsequent outcomes. The described models can be used to identify people most likely to have a breakthrough seizure, a seizure recurrence following a breakthrough seizure, and to achieve 12-month remission following a breakthrough seizure. The results suggest that focussing on achieving 12-month remission swiftly represents the best therapeutic aim to reduce the risk of a breakthrough seizure and subsequent negative outcomes. This will aid individual patient risk stratification and the design of future epilepsy trials. PMID:29267375

Fitness, motor competence, and body composition are weakly associated with adolescent back pain.

PubMed

Perry, Mark; Straker, Leon; O'Sullivan, Peter; Smith, Anne; Hands, Beth

2009-06-01

Cross-sectional survey. To assess the associations between adolescent back pain and fitness, motor competence, and body composition. Although deficits in physical fitness and motor control have been shown to relate to adult back pain, the evidence in adolescents is less clear. In this cross-sectional study, 1608 "Raine" cohort adolescents (mean age, 14 years) answered questions on lifetime, month, and chronic prevalence of back pain, and participated in a range of physical tests assessing aerobic capacity, muscle performance, flexibility, motor competence, and body composition.A history of any diagnosed back pain in the adolescent was obtained from the primary caregiver. After multivariate logistic regression analysis, increased likelihood of back pain in boys was associated with greater aerobic capacity, greater waist girth, and both reduced and greater flexibility. Back pain in girls was associated with greater abdominal endurance, reduced kinesthetic integration, and both reduced and greater back endurance. Lower likelihood of back pain was associated with greater bimanual dexterity in boys and greater lower extremity power in girls. Physical characteristics are commonly cited as important risk factors in back pain development. Although some factors were associated with adolescent back pain, and these differed between boys and girls, they made only a small contribution to logistic regression models for back pain. The results suggest future work should explore the interaction of multiple domains of risk factors (physical, lifestyle, and psychosocial) and subgroups of adolescent back pain, for whom different risk factors may be important.

Risk and Protective Factors Associated with Trajectories of Depressed Mood from Adolescence to Early Adulthood

PubMed Central

Costello, Darcé M.; Swendsen, Joel; Rose, Jennifer S.; Dierker, Lisa C.

2009-01-01

This study used semi-parametric group-based modeling to explore unconditional and conditional trajectories of self-reported depressed mood from age 12 to 25. Drawing on data from the National Longitudinal Study of Adolescent Health (N=11,559), four distinct trajectories were identified: no depressed mood, stable low depressed mood, early high declining depressed mood, and late escalating depressed mood. Baseline risk factors associated with greater likelihood of membership in depressed mood trajectory groups compared to the no depressed mood group included being female, Black/African American, Hispanic/Latino American, or Asian American, lower SES, using alcohol, tobacco, or other drugs on a weekly basis, and delinquent behavior. Baseline protective factors associated with greater likelihood of membership in the no depressed mood group compared to the depressed mood trajectory groups included two-parent family structure, feeling connected to parents, peers, or school, and self esteem. With the exception of delinquent behavior, risk and protective factors also distinguished the likelihood of membership among several of the three depressed mood groups. The results add to basic etiologic research regarding developmental pathways of depressed mood in adolescence and young adulthood. PMID:18377115

The pitfalls of hair analysis for toxicants in clinical practice: three case reports.

PubMed Central

Frisch, Melissa; Schwartz, Brian S

2002-01-01

Hair analysis is used to assess exposure to heavy metals in patients presenting with nonspecific symptoms and is a commonly used procedure in patients referred to our clinic. We are frequently called on to evaluate patients who have health-related concerns as a result of hair analysis. Three patients first presented to outside physicians with nonspecific, multisystemic symptoms. A panel of analytes was measured in hair, and one or more values were interpreted as elevated. As a result of the hair analysis and other unconventional diagnostic tests, the patients presented to us believing they suffered from metal toxicity. In this paper we review the clinical efficacy of this procedure within the context of a patient population with somatic disorders and no clear risk factors for metal intoxication. We also review limitations of hair analysis in this setting; these limitations include patient factors such as low pretest probability of disease and test factors such as the lack of validation of analytic techniques, the inability to discern between exogenous contaminants and endogenous toxicants in hair, the variability of analytic procedures, low interlaboratory reliability, and the increased likelihood of false positive test results in the measurement of panels of analytes. PMID:11940463

External Insect Morphology: A Negative Factor in Attitudes toward Insects and Likelihood of Incorporation in Future Science Education Settings

ERIC Educational Resources Information Center

Wagler, Ron; Wagler, Amy

2012-01-01

This study investigated if the external morphology of an insect had a negative effect on United States (US) preservice elementary teacher's attitudes toward insects and beliefs concerning the likelihood of incorporating insects into future science education settings. 270 US kindergarten through sixth grade preservice elementary teachers…

International Sexual Partnerships May Be Shaped by Sexual Histories and Socioeconomic Status

PubMed Central

Truong, Hong-Ha M.; Mehrotra, Megha; Montoya, Orlando; Lama, Javier R.; Guanira, Juan V.; Casapía, Martín; Veloso, Valdiléa G.; Buchbinder, Susan P.; Mayer, Kenneth H.; Chariyalertsak, Suwat; Schechter, Mauro; Bekker, Linda-Gail; Kallás, Esper G.; Grant, Robert M.

2017-01-01

Exchange sex and higher education were associated with an increased likelihood of international sexual partnerships (ISPs). Exchange sex and older age were associated with an increased likelihood of condomless sex in ISPs. Educational and socioeconomic factors may create unbalanced power dynamics that influence exchange sex and condomless sex in ISPs. PMID:28407648

Predicting the Likelihood of Going to Graduate School: The Importance of Locus of Control

ERIC Educational Resources Information Center

Nordstrom, Cynthia R.; Segrist, Dan J.

2009-01-01

Although many undergraduates apply to graduate school, only a fraction will be admitted. A question arises as to what factors relate to the likelihood of pursuing graduate studies. The current research examined this question by surveying students in a Careers in Psychology course. We hypothesized that GPA, a more internal locus of control…

Factors Influencing the Likelihood of Overeducation: A Bivariate Probit with Sample Selection Framework

ERIC Educational Resources Information Center

Rubb, Stephen

2014-01-01

Contrary to expectations, the likelihood of overeducation is shown to be inversely related to unemployment rates when not control for selectivity. Furthermore, incidence data show that overeducation is more common among men than women and among Whites than Blacks. At issue is selectivity: employment must be selected for overeducation to occur.…

The fluid events model: Predicting continuous task action change.

PubMed

Radvansky, Gabriel A; D'Mello, Sidney; Abbott, Robert G; Morgan, Brent; Fike, Karl; Tamplin, Andrea K

2015-01-01

The fluid events model is a behavioural model aimed at predicting the likelihood that people will change their actions in ongoing, interactive events. From this view, not only are people responding to aspects of the environment, but they are also basing responses on prior experiences. The fluid events model is an attempt to predict the likelihood that people will shift the type of actions taken within an event on a trial-by-trial basis, taking into account both event structure and experience-based factors. The event-structure factors are: (a) changes in event structure, (b) suitability of the current action to the event, and (c) time on task. The experience-based factors are: (a) whether a person has recently shifted actions, (b) how often a person has shifted actions, (c) whether there has been a dip in performance, and (d) a person's propensity to switch actions within the current task. The model was assessed using data from a series of tasks in which a person was producing responses to events. These were two stimulus-driven figure-drawing studies, a conceptually driven decision-making study, and a probability matching study using a standard laboratory task. This analysis predicted trial-by-trial action switching in a person-independent manner with an average accuracy of 70%, which reflects a 34% improvement above chance. In addition, correlations between overall switch rates and actual switch rates were remarkably high (mean r = .98). The experience-based factors played a more major role than the event-structure factors, but this might be attributable to the nature of the tasks.

Analysis of Social and Genetic Factors Influencing Heterosexual Transmission of HIV within Serodiscordant Couples in the Henan Cohort

PubMed Central

Zhang, Yilei; Li, Jie; Ma, Xuejun; Li, Ning; Wang, Qi; Xue, Xiujuan; Luo, Le; Li, Zizhao; Ring, Huijun Z.; Ring, Brian Z.; Su, Li

2015-01-01

There is considerable variability between individuals in susceptibility to infection by human immunodeficiency virus (HIV). Many social, clinical and genetic factors are known to contribute to the likelihood of HIV transmission, but there is little consensus on the relative importance and potential interaction of these factors. Additionally, recent studies of several variants in chemokine receptors have identified alleles that may be predictive of HIV transmission and disease progression; however the strengths and directions of the associations of these genetic markers with HIV transmission have markedly varied between studies. To better identify factors that predict HIV transmission in a Chinese population, 180 cohabiting serodiscordant couples were enrolled for study by the Henan Center for Disease Prevention and Control, and transmission and progression of HIV infection were regularly measured. We found that anti-retroviral therapy, education level, and condom use were the most significant factors in determining likelihood of HIV transmission in this study. We also assessed ten variants in three genes (CXCL12, CCR2, and CCR5) that have been shown to influence HIV transmission. We found two tightly linked variants in CCR2 and CCR5, rs1799864 and rs1800024, have a significant positive association with transmission as recessive models (OR>10, P value=0.011). Mixed effects models showed that these genetic variants both retained significance when assessed with either treatment or condom use. These markers of transmission susceptibility may therefore serve to help stratify individuals by risk for HIV transmission. PMID:26068906

The impact of food intake and social habits on embryo quality and the likelihood of blastocyst formation.

PubMed

Braga, Daniela Paes Almeida Ferreira; Halpern, Gabriela; Setti, Amanda S; Figueira, Rita Cássia S; Iaconelli, Assumpto; Borges, Edson

2015-07-01

The aim of this study was to evaluate the influence of patients' lifestyle factors and eating habits on embryo development. A total of 2659 embryos recovered from 269 patients undergoing intracytoplasmic sperm injection cycles were included. The frequency of intake of food items and social habits were registered and its influences on embryo development evaluated. The consumption of cereals, vegetables and fruits positively influenced the embryo quality at the cleavage stage. The quality of the embryo at the cleavage stage was also negatively correlated with the consumption of alcoholic drinks and smoking habits. The consumption of fruits influenced the likelihood of blastocyst formation, which was also positively affected by the consumption of fish. Being on a weight-loss diet and consumption of red meat had a negative influence on the likelihood of blastocyst formation. The likelihood of blastocyst formation was also negatively influenced by the consumption of alcoholic drinks and by smoking habits. The consumption of red meat and body mass index had a negative effect on the implantation rate and the likelihood of pregnancy. In addition, being on a weight-loss diet had a negative influence on implantation rate. Our evidence suggests a possible relationship between environmental factors and ovary biology. Copyright © 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Space operations and the human factor

NASA Astrophysics Data System (ADS)

Brody, Adam R.

1993-10-01

Although space flight does not put the public at high risk, billions of dollars in hardware are destroyed and the space program halted when an accident occurs. Researchers are therefore applying human-factors techniques similar to those used in the aircraft industry, albeit at a greatly reduced level, to the spacecraft environment. The intent is to reduce the likelihood of catastrophic failure. To increase safety and efficiency, space human factors researchers have simulated spacecraft docking and extravehicular activity rescue. Engineers have also studied EVA suit mobility and aids. Other basic human-factors issues that have been applied to the space environment include antropometry, biomechanics, and ergonomics. Workstation design, workload, and task analysis currently receive much attention, as do habitability and other aspects of confined environments. Much work also focuses on individual payloads, as each presents its own complexities.

Factoring handedness data: II. Geschwind's multidimensional hypothesis.

PubMed

Messinger, H B; Messinger, M I

1996-06-01

The challenge in this journal by Peters and Murphy to the validity of two published factor analyses of handedness data because of bimodality was dealt with in Part I by identifying measures to normalize the handedness item distributions. A new survey using Oldfield's questionnaire format had 38 bell-shaped (unimodal) handedness-item distributions and 11 that were only marginally bimodal out of the 55 items used in Geschwind's 1986 study. Yet they were still non-normal and the factor analysis was unsatisfactory; bimodality is not the only problem. By choosing a transformation for each item that was optimal as assessed by D'Agostino's K2 statistic, all but two items could be normalized. Seven factors were derived that showed high congruence between maximum likelihood and principal components extractions before and after varimax rotation. Geschwind's assertion that handedness is not unidimensional is therefore supported.

Video Analysis of Anterior Cruciate Ligament (ACL) Injuries

PubMed Central

Carlson, Victor R.; Sheehan, Frances T.; Boden, Barry P.

2016-01-01

Background: As the most viable method for investigating in vivo anterior cruciate ligament (ACL) rupture, video analysis is critical for understanding ACL injury mechanisms and advancing preventative training programs. Despite the limited number of published studies involving video analysis, much has been gained through evaluating actual injury scenarios. Methods: Studies meeting criteria for this systematic review were collected by performing a broad search of the ACL literature with use of variations and combinations of video recordings and ACL injuries. Both descriptive and analytical studies were included. Results: Descriptive studies have identified specific conditions that increase the likelihood of an ACL injury. These conditions include close proximity to opposing players or other perturbations, high shoe-surface friction, and landing on the heel or the flat portion of the foot. Analytical studies have identified high-risk joint angles on landing, such as a combination of decreased ankle plantar flexion, decreased knee flexion, and increased hip flexion. Conclusions: The high-risk landing position appears to influence the likelihood of ACL injury to a much greater extent than inherent risk factors. As such, on the basis of the results of video analysis, preventative training should be applied broadly. Kinematic data from video analysis have provided insights into the dominant forces that are responsible for the injury (i.e., axial compression with potential contributions from quadriceps contraction and valgus loading). With the advances in video technology currently underway, video analysis will likely lead to enhanced understanding of non-contact ACL injury. PMID:27922985

Determining consumer purchase intentions: the importance of dry matter, size, and price of kiwifruit.

PubMed

Jaeger, Sara R; Harker, Roger; Triggs, Chris M; Gunson, Anne; Campbell, Rachel L; Jackman, Richard; Requejo-Jackman, Cecilia

2011-04-01

Knowledge of the relative importance of food quality attributes in determining consumer purchase intention is critical for robust assessment of economic opportunities for industry growth. The aim of this study is to demonstrate how conjoint analysis methodology that incorporates tasting of fruit can be used to collect such information. Three hundred Japanese consumers took part in research designed to measure the importance of dry matter (DM), size, and price of kiwifruit (Actinidia deliciosa "Hayward" and Actinidia chinensis "Hort16A") for purchase intention. Measurement of consumer liking for kiwifruit of different DM content was a key first step. Liking increased as DM increased and was accompanied by increased purchase likelihood/choice probability for kiwifruit. The size of kiwifruit presented to consumers varied from "small" to "extra large." Consumers liked "mid-sized" kiwifruit over "small" or "extra-large" kiwifruit. Despite these differences in liking, size was of little importance in determining purchase likelihood/choice probability for kiwifruit. Price was a very important factor in determining purchase likelihood/choice probability but was less important than DM content. As price increased, purchase likelihood/choice probability decreased. Beneath these general findings, heterogeneity existed. Some consumers placed more/less importance on the focal purchase drivers than suggested by the aggregate model. Overall, the results suggest that incentive schemes already implemented by industry should consider rewarding high-DM fruit more than fruit size.   This research has contributed to the New Zealand kiwifruit industry gaining a better understanding of the relative importance consumers place on DM, size, and price of kiwifruit and has resulted in changes to grower incentive schemes. The research approach presented forces consumer to tradeoff attributes of kiwifruit against each other and decide on how important two key quality attributes-DM and size-are relative to each other and relative to price. The application of conjoint analysis in this article can be transferred to other fruits, food, and beverages and help guide consumer-led innovation.

Spatial analysis of choice of place of delivery in Nigeria.

PubMed

Gayawan, Ezra

2014-06-01

Access to quality healthcare during childbirth is a crucial factor for taming maternal and child mortality and morbidity. Increasing this access in developing countries depends on understanding the factors influencing maternal healthcare decision at a geographical location. This study analyzes spatial pattern in choice of place of delivery in Nigeria. Data analyzed came from Nigerian Demographic and Health Survey data set. The choice of place delivery was considered a multi-categorical response and a multinomial logistic regression model used to evaluate spatial variations in choosing a particular place to deliver against home delivery. Results show a north-south divide in choosing health facilities against homes for delivery. The likelihood of institutional delivery was significantly lower for women residing in Bayelsa and the majority of the states in northern Nigeria. As women advance in age, they have more likelihood of having institutional deliveries. Other contributing factors that favor institutional deliveries include use of antenatal care services, urban dwelling, mass media and parity. Usage of mass media to campaign for institutional deliveries particularly in northern Nigeria, among younger women and those of higher parity; encouraging the use of antenatal services and even distribution of health facilities making them easily accessible to rural women are important for enhancing chances of institutional deliveries. Also, state-specific policies in this regard are indispensable. Copyright © 2014 Elsevier B.V. All rights reserved.

THESEUS: maximum likelihood superpositioning and analysis of macromolecular structures.

PubMed

Theobald, Douglas L; Wuttke, Deborah S

2006-09-01

THESEUS is a command line program for performing maximum likelihood (ML) superpositions and analysis of macromolecular structures. While conventional superpositioning methods use ordinary least-squares (LS) as the optimization criterion, ML superpositions provide substantially improved accuracy by down-weighting variable structural regions and by correcting for correlations among atoms. ML superpositioning is robust and insensitive to the specific atoms included in the analysis, and thus it does not require subjective pruning of selected variable atomic coordinates. Output includes both likelihood-based and frequentist statistics for accurate evaluation of the adequacy of a superposition and for reliable analysis of structural similarities and differences. THESEUS performs principal components analysis for analyzing the complex correlations found among atoms within a structural ensemble. ANSI C source code and selected binaries for various computing platforms are available under the GNU open source license from http://monkshood.colorado.edu/theseus/ or http://www.theseus3d.org.

Work-related injury factors and safety climate perception in truck drivers.

PubMed

Anderson, Naomi J; Smith, Caroline K; Byrd, Jesse L

2017-08-01

The trucking industry has a high burden of work-related injuries. This study examined factors, such as safety climate perceptions, that may impact injury risk. A random sample of 9800 commercial driver's license holders (CDL) were sent surveys, only 4360 were eligible truck drivers. Descriptive statistics and logistic regression models were developed to describe the population and identify variables associated with work-related injury. 2189 drivers completed the pertinent interview questions. Driving less-than-truckload, daytime sleepiness, pressure to work faster, and having a poor composite score for safety perceptions were all associated with increased likelihood of work-related injury. Positive safety perception score was protective for odds of work-related injury, and increased claim filing when injured. Positive psychological safety climate is associated with decreased likelihood of work-related injury and increased likelihood that a driver injured on the job files a workers' compensation claim. © 2017 Wiley Periodicals, Inc.

The Analysis of the Contribution of Human Factors to the In-Flight Loss of Control Accidents

NASA Technical Reports Server (NTRS)

Ancel, Ersin; Shih, Ann T.

2012-01-01

In-flight loss of control (LOC) is currently the leading cause of fatal accidents based on various commercial aircraft accident statistics. As the Next Generation Air Transportation System (NextGen) emerges, new contributing factors leading to LOC are anticipated. The NASA Aviation Safety Program (AvSP), along with other aviation agencies and communities are actively developing safety products to mitigate the LOC risk. This paper discusses the approach used to construct a generic integrated LOC accident framework (LOCAF) model based on a detailed review of LOC accidents over the past two decades. The LOCAF model is comprised of causal factors from the domain of human factors, aircraft system component failures, and atmospheric environment. The multiple interdependent causal factors are expressed in an Object-Oriented Bayesian belief network. In addition to predicting the likelihood of LOC accident occurrence, the system-level integrated LOCAF model is able to evaluate the impact of new safety technology products developed in AvSP. This provides valuable information to decision makers in strategizing NASA's aviation safety technology portfolio. The focus of this paper is on the analysis of human causal factors in the model, including the contributions from flight crew and maintenance workers. The Human Factors Analysis and Classification System (HFACS) taxonomy was used to develop human related causal factors. The preliminary results from the baseline LOCAF model are also presented.

Identification of contemporary selection signatures using composite log likelihood and their associations with marbling score in Korean cattle.

PubMed

Ryu, Jihye; Lee, Chaeyoung

2014-12-01

Positive selection not only increases beneficial allele frequency but also causes augmentation of allele frequencies of sequence variants in close proximity. Signals for positive selection were detected by the statistical differences in subsequent allele frequencies. To identify selection signatures in Korean cattle, we applied a composite log-likelihood (CLL)-based method, which calculates a composite likelihood of the allelic frequencies observed across sliding windows of five adjacent loci and compares the value with the critical statistic estimated by 50,000 permutations. Data for a total of 11,799 nucleotide polymorphisms were used with 71 Korean cattle and 209 foreign beef cattle. As a result, 147 signals were identified for Korean cattle based on CLL estimates (P < 0.01). The signals might be candidate genetic factors for meat quality by which the Korean cattle have been selected. Further genetic association analysis with 41 intragenic variants in the selection signatures with the greatest CLL for each chromosome revealed that marbling score was associated with five variants. Intensive association studies with all the selection signatures identified in this study are required to exclude signals associated with other phenotypes or signals falsely detected and thus to identify genetic markers for meat quality. © 2014 Stichting International Foundation for Animal Genetics.

Insecticide resistance, control failure likelihood and the First Law of Geography.

PubMed

Guedes, Raul Narciso C

2017-03-01

Insecticide resistance is a broadly recognized ecological backlash resulting from insecticide use and is widely reported among arthropod pest species with well-recognized underlying mechanisms and consequences. Nonetheless, insecticide resistance is the subject of evolving conceptual views that introduces a different concept useful if recognized in its own right - the risk or likelihood of control failure. Here we suggest an experimental approach to assess the likelihood of control failure of an insecticide allowing for consistent decision-making regarding management of insecticide resistance. We also challenge the current emphasis on limited spatial sampling of arthropod populations for resistance diagnosis in favor of comprehensive spatial sampling. This necessarily requires larger population sampling - aiming to use spatial analysis in area-wide surveys - to recognize focal points of insecticide resistance and/or control failure that will better direct management efforts. The continuous geographical scale of such surveys will depend on the arthropod pest species, the pattern of insecticide use and many other potential factors. Regardless, distance dependence among sampling sites should still hold, following the maxim that the closer two things are, the more they resemble each other, which is the basis of Tobler's First Law of Geography. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Pathways to Early Coital Debut for Adolescent Girls: A Recursive Partitioning Analysis

PubMed Central

Pearson, Matthew R.; Kholodkov, Tatyana; Henson, James M.; Impett, Emily A.

2011-01-01

The current study examined pathways to early coital debut among early to middle adolescent girls in the United States. In a two-year longitudinal study of 104 adolescent girls, we conducted Recursive Partitioning (RP) analyses to examine the specific factors that were related to engaging in first intercourse by the 10th grade among adolescent girls who had not yet engaged in sexual intercourse by the 8th grade. RP analyses identified subsamples of girls who had low, medium, and high likelihoods of engaging in early coital debut based on six variables (i.e., school aspirations, early physical intimacy experiences, depression, body objectification, body image, and relationship inauthenticity). For example, girls in the lowest likelihood group (3% had engaged in sex by the 10th grade) reported no prior experiences with being touched under their clothes, low body objectification, high aspirations to complete graduate education, and low depressive symptoms; girls in the highest likelihood group (75% had engaged in sex by the 10th grade) also reported no prior experiences with being touched under their clothes but had high levels of body objectification. The implications of these analyses for the development of female adolescent sexuality as well as for advances in quantitative methods are discussed. PMID:21512947

Pedophiles: mental retardation, maternal age, and sexual orientation.

PubMed

Blanchard, R; Watson, M S; Choy, A; Dickey, R; Klassen, P; Kuban, M; Ferren, D J

1999-04-01

Intellectual functioning, parental age, and sexual orientation in 991 male sexual offenders were investigated. Sources of data included semistructured interviews, clinical charts, phallometric tests, and self-administered questionnaires. The results suggest two main conclusions: (i) Among pedophiles in general, erotic preference moves away from adult women along two dimensions: age and sex. The extent of this movement is greater, along both dimensions, for pedophiles with lower levels of intellectual functioning. (ii) High maternal age (or some factor it represents) increases the likelihood of exclusive sexual interest in boys. Intellectual deficiency (or some factor it represents) decreases the likelihood of exclusive sexual interest in girls. These two factors summate, so that a pedophile with both factors is more likely to be sexually interested in boys than a pedophile with only one.

Factors determining family planning in Catalonia. Sources of inequity

PubMed Central

2012-01-01

Introduction In recent decades, the foreign population in Spain has increased significantly, particularly for Catalonia, an autonomous region of Spain (2.90% in 2000 and 15.95% in 2010) and in particular Girona province (6.18% in 2000 and 21.55% in 2010). Several studies have shown a lower use of family planning methods by immigrants. This same trend is observed in Spain. The objective of this paper is to determine the existence of differences and possible sources of inequity in the use of family planning methods among health service users in Catalonia (Spain) by sex, health status, place of birth and socioeconomic conditions. Methods Data were taken from an ad-hoc questionnaire which was compiled following a qualitative stage of individual interviews. Said questionnaire was administered to 1094 Catalan public health service users during 2007. A complete descriptive analysis was carried out for variables related to public health service users’ sociodemographic characteristics and variables indicating knowledge and use of family planning methods, and bivariate relationships were analysed by means of chi-square contrasts. Considering the use (or non-use) of family planning methods as a dependent variable and a set of demographic, socioeconomic and health status variables as explanatory factors, the relationship was modelled using mixed models. Results The analysed sample is comprised of 54.3% women and 45.7% men, with 74.3% natives (or from the EU) and 25.7% economic immigrants. 54.8% use some method of family planning, the condom (46.7%) and the pill (28.0%) being the two most frequently used methods. Statistical modelling indicates that those factors which most influence the use of family planning methods are level of education (30.59% and 39.29% more likelihood) and having children over 14 (35.35% more likelihood). With regard to the origin of the user, we observe that patients from North Africa,sub. Saharan Africa and Asia are less likely to use family planning methods (36.68%, 38.59% and 70.51%, respectively). Conclusions The use of family planning methods is positively related to a higher level of education and having children over 14. Factors such as sex, age, income and self-perceived health do not appear to influence their use. Furthermore, being a native of this country, the European Union or Central/South America represents a greater likelihood of use than being African or Asian. Although no general differences in use were found between sexes, the difference found in the case of Asian women stands out, with a higher likelihood of use. PMID:22818829

Factors determining family planning in Catalonia. Sources of inequity.

PubMed

Saurina, Carme; Vall-Llosera, Laura; Saez, Marc

2012-07-20

In recent decades, the foreign population in Spain has increased significantly, particularly for Catalonia, an autonomous region of Spain (2.90% in 2000 and 15.95% in 2010) and in particular Girona province (6.18% in 2000 and 21.55% in 2010). Several studies have shown a lower use of family planning methods by immigrants. This same trend is observed in Spain. The objective of this paper is to determine the existence of differences and possible sources of inequity in the use of family planning methods among health service users in Catalonia (Spain) by sex, health status, place of birth and socioeconomic conditions. Data were taken from an ad-hoc questionnaire which was compiled following a qualitative stage of individual interviews. Said questionnaire was administered to 1094 Catalan public health service users during 2007. A complete descriptive analysis was carried out for variables related to public health service users' sociodemographic characteristics and variables indicating knowledge and use of family planning methods, and bivariate relationships were analysed by means of chi-square contrasts. Considering the use (or non-use) of family planning methods as a dependent variable and a set of demographic, socioeconomic and health status variables as explanatory factors, the relationship was modelled using mixed models. The analysed sample is comprised of 54.3% women and 45.7% men, with 74.3% natives (or from the EU) and 25.7% economic immigrants. 54.8% use some method of family planning, the condom (46.7%) and the pill (28.0%) being the two most frequently used methods. Statistical modelling indicates that those factors which most influence the use of family planning methods are level of education (30.59% and 39.29% more likelihood) and having children over 14 (35.35% more likelihood). With regard to the origin of the user, we observe that patients from North Africa,sub. Saharan Africa and Asia are less likely to use family planning methods (36.68%, 38.59% and 70.51%, respectively). The use of family planning methods is positively related to a higher level of education and having children over 14. Factors such as sex, age, income and self-perceived health do not appear to influence their use. Furthermore, being a native of this country, the European Union or Central/South America represents a greater likelihood of use than being African or Asian. Although no general differences in use were found between sexes, the difference found in the case of Asian women stands out, with a higher likelihood of use.

Identifying patients with chronic hepatitis B at high risk of type 2 diabetes mellitus: a cross-sectional study with pair-matched controls.

PubMed

Shen, Yi; Zhang, Jian; Cai, Hui; Shao, Jian-Guo; Zhang, You-Yi; Liu, Yan-Mei; Qin, Gang; Qin, Yan

2015-03-19

The presence of diabetes mellitus (DM) is associated with increased liver morbidity and mortality risk in patients with chronic hepatitis B (CHB). Aim of this study was to identify factors associated with type 2 diabetes mellitus (T2DM) in CHB patients. A cross-sectional study with pair-matched controls was conducted in Nantong Third People's Hospital, Nantong University, China. From January 2008 to December 2012, a total of 1783 CHB patients were screened for study subjects, among whom 207 patients with T2DM were enrolled as cases and 207 sex- and age-matched non-DM patients as controls. Demographic, anthropometric, lifestyle, clinical, and laboratory data were obtained from each subject. In the univariate model, thirteen variables showed marked differences between the DM group and non-DM group. Patients with longer duration of CHB (≥15 years) and alcoholic steatosis showed the highest likelihood of T2DM (odds ratio = 5.39 and 4.95; 95% confidence intervals 2.76-10.53 and 1.65-14.91). In the multivariate adjusted analysis, three CHB-related factors, namely high viral load, long duration of illness, and presence of cirrhosis, contributed to substantially increase the likelihood of T2DM, in addition to the other five risk factors including family history of DM, low education level, elevated triglycerides (TG), gamma-glutamyl transferase (GGT) levels, and presence of alcoholic steatosis. Our findings suggest that high viral load, long duration of CHB, presence of cirrhosis, alcoholic steatosis and several other factors may be potential risk factors for development of T2DM in CHB patients. It is of vital importance to monitor glucose in high-risk CHB patients and aggressively intervene on modifiable risk factors.

Spontaneous passage of ureteral stones in patients with indwelling ureteral stents.

PubMed

Baumgarten, Lee; Desai, Anuj; Shipman, Scott; Eun, Daniel D; Pontari, Michel A; Mydlo, Jack H; Reese, Adam C

2017-10-01

To determine rates of spontaneous ureteral stone passage in patients with indwelling ureteral stents, and to identify factors associated with the spontaneous passage of stones while a ureteral stent is in place. From our institutional database, we identified patients who underwent ureteroscopic procedures for stone disease between January 1, 2013 and March 1, 2015. We compared the rates of spontaneous stone passage between patients who had previously undergone ureteral stent placement and those who had not. In patients with indwelling stents, multivariate logistic regression was performed to identify factors associated with spontaneous stone passage. A total of 194 patients met inclusion criteria. Spontaneous stone passage rates were similar in the stented (17/119, 14%) and non-stented (15/75, 20%) groups (p = 0.30). In bivariate analysis of stented patients, smaller stone size (p < 0.001) and distal stone location (p = 0.01) were significantly associated with spontaneous stone passage. Multivariate logistic regression analysis of stented patients showed that only small stone size was significantly associated with the likelihood of stone passage (p = 0.01), whereas stent duration, stone location, and stone laterality were not. A small, but clinically significant percentage of ureteral stones pass spontaneously with a ureteral stent in place. Small stone size is associated with an increased likelihood of spontaneous passage in patients with indwelling stents. These findings may help to identify patients who can potentially avoid additional surgical procedures for definitive stone removal after ureteral stent placement.

Environmental and psychological correlates of older adult's active commuting.

PubMed

Panter, Jenna R; Jones, Andrew P; van Sluijs, Esther M F; Griffin, Simon J; Wareham, Nicholas J

2011-07-01

This study explored the environmental and psychological correlates of active commuting in a sample of adults from the European Prospective Investigation into Cancer Norfolk cohort. Members of the cohort who were in employment, lived within 10 km of work, and did not report a limitation that precluded walking were included in this analysis. Psychological factors, perceptions of the neighborhood environment and travel mode to work were reported using questionnaires. Neighborhood and route environmental characteristics were estimated objectively using a geographical information system. The mediating effects of psychological factors were assessed using a series of regression models. A total of 1279 adults (mean age=60.4 yr, SD=5.4 yr) were included in this analysis, of whom 25% actively commuted to work. In multivariable regression analyses, those who reported strong habits for walking or cycling were more likely to actively commute, whereas those living 4-10 km from work were less likely to actively commute. In addition, living in a rural area was associated with a decreased likelihood of men's active commuting, and in women, living in a neighborhood with high road density and having a route to work that was not on a main or secondary road was associated with an increased likelihood of active commuting. There was weak evidence that habit acted to partly mediate the associations between environmental correlates and active commuting in both sexes. The findings suggest that interventions designed to encourage the development of habitual behaviors for active commuting may be effective, especially among those living close to work.

Factors associated with surgical management in an underinsured, safety net population.

PubMed

Winton, Lisa M; Nodora, Jesse N; Martinez, Maria Elena; Hsu, Chiu-Hsieh; Djenic, Brano; Bouton, Marcia E; Aristizabal, Paula; Ferguson, Elizabeth M; Weiss, Barry D; Komenaka, Ian K

2016-02-01

Few studies include significant numbers of racial and ethnic minority patients. The current study was performed to examine factors that affect breast cancer operations in an underinsured population. We performed a retrospective review of all breast cancer patients from January 2010 to May 2012. Patients with American Joint Committee on Cancer clinical stage 0-IIIA breast cancer underwent evaluation for type of operation: breast conservation, mastectomy alone, and reconstruction after mastectomy. The population included 403 patients with mean age 53 years. Twelve of the 50 patients (24%) diagnosed at stage IIIB presented with synchronous metastatic disease. Of the remaining patients, only 2 presented with metastatic disease (0.6%). The initial operation was 65% breast conservation, 26% mastectomy alone, and 10% reconstruction after mastectomy. Multivariate analysis revealed that Hispanic ethnicity (odds ratio [OR], 0.38; 95% CI, 0.19-0.73; P = .004), presentation with palpable mass (OR, 0.34; 95% CI, 0.13-0.90; P = .03), preoperative chemotherapy (OR, 0.25; 95% CI, 0.10-0.62; P = .003) were associated with a lesser likelihood of mastectomy. Multivariate analysis of factors associated with reconstruction after mastectomy showed that operation with Breast surgical oncologist (OR, 18.4; 95% CI, 2.18-155.14; P < .001) and adequate health literacy (OR, 3.13; 95% CI, 0.95-10.30; P = .06) were associated with reconstruction. The majority of safety net patients can undergo breast conservation despite delayed presentation and poor use of screening mammography. Preoperative chemotherapy increased the likelihood of breast conservation. Routine systemic workup in patients with operable breast cancer is not indicated. Copyright © 2016 Elsevier Inc. All rights reserved.

Cross-sectional study of female sex workers in Soweto, South Africa: Factors associated with HIV infection.

PubMed

Coetzee, Jenny; Jewkes, Rachel; Gray, Glenda E

2017-01-01

In South Africa, the rate of HIV in the sex worker (SW) population is exceedingly high, but critical gaps exist in our understanding of SWs and the factors that make them vulnerable to HIV. This study aimed to estimate HIV prevalence among female sex workers (FSWs) in Soweto, South Africa, and to describe their sexual behavior and other factors associated with HIV infection. A cross-sectional, respondent-driven sampling (RDS) recruitment methodology was used to enroll 508 FSWs based in Soweto. Data were collected using a survey instrument, followed by two HIV rapid tests. Raw and RDS adjusted data were analyzed using a chi-squared test of association and multivariate logistic regression to show factors associated with HIV infection. HIV prevalence among FSWs was 53.6% (95% CI 47.5-59.9). FSWs were almost exclusively based in taverns (85.6%) and hostels (52.0%). Less than a quarter (24.4%) were under 25 years of age. Non-partner violence was reported by 55.5%, 59.6% of whom were HIV-infected. Advancing age, incomplete secondary schooling, migrancy and multiple clients increased the likelihood of HIV acquisition: >30 years of age was associated with a 4.9 times (95% CI 2.6-9.3) increased likelihood of HIV; incomplete secondary schooling almost tripled the likelihood (AOR 2.8, 95% CI 1.6-5.0); being born outside of the Gauteng province increased the likelihood of HIV 2.3 times (95% CI 1.3-4.0); and having more than five clients per day almost doubled the likelihood (AOR 1.9, 95% CI 1.1-3.2). Our findings highlight the extreme vulnerability of FSWs to HIV. Advancing age, limited education and multiple clients were risk factors associated with HIV, strongly driven by a combination of structural, biological and behavioral determinants. Evidence suggests that interventions need to be carefully tailored to the varying profiles of SW populations across South Africa. Soweto could be considered a microcosm of South Africa in terms of the epidemic of violence and HIV experienced by the SW population, which is influenced by factors often beyond an individual level of control. While describing a hitherto largely undocumented population of FSWs, our findings confirm the urgent need to scale up innovative HIV prevention and treatment programs for this population.

Flow cytometry for feline lymphoma: a retrospective study regarding pre-analytical factors possibly affecting the quality of samples.

PubMed

Martini, Valeria; Bernardi, Serena; Marelli, Priscilla; Cozzi, Marzia; Comazzi, Stefano

2018-06-01

Objectives Flow cytometry (FC) is becoming increasingly popular among veterinary oncologists for the diagnosis of lymphoma or leukaemia. It is accurate, fast and minimally invasive. Several studies of FC have been carried out in canine oncology and applied with great results, whereas there is limited knowledge and use of this technique in feline patients. This is mainly owing to the high prevalence of intra-abdominal lymphomas in this species and the difficulty associated with the diagnostic procedures needed to collect the sample. The purpose of the present study is to investigate whether any pre-analytical factor might affect the quality of suspected feline lymphoma samples for FC analysis. Methods Ninety-seven consecutive samples of suspected feline lymphoma were retrospectively selected from the authors' institution's FC database. The referring veterinarians were contacted and interviewed about several different variables, including signalment, appearance of the lesion, features of the sampling procedure and the experience of veterinarians performing the sampling. Statistical analyses were performed to assess the possible influence of these variables on the cellularity of the samples and the likelihood of it being finally processed for FC. Results Sample cellularity is a major factor in the likelihood of the sample being processed. Moreover, sample cellularity was significantly influenced by the needle size, with 21 G needles providing the highest cellularity. Notably, the sample cellularity and the likelihood of being processed did not vary between peripheral and intra-abdominal lesions. Approximately half of the cats required pharmacological restraint. Side effects were reported in one case only (transient swelling after peripheral lymph node sampling). Conclusions and relevance FC can be safely applied to cases of suspected feline lymphomas, including intra-abdominal lesions. A 21 G needle should be preferred for sampling. This study provides the basis for the increased use of this minimally invasive, fast and cost-effective technique in feline medicine.

General Practitioners' Attitudes Toward a Web-Based Mental Health Service for Adolescents: Implications for Service Design and Delivery.

PubMed

Subotic-Kerry, Mirjana; King, Catherine; O'Moore, Kathleen; Achilles, Melinda; O'Dea, Bridianne

2018-03-23

Anxiety disorders and depression are prevalent among youth. General practitioners (GPs) are often the first point of professional contact for treating health problems in young people. A Web-based mental health service delivered in partnership with schools may facilitate increased access to psychological care among adolescents. However, for such a model to be implemented successfully, GPs' views need to be measured. This study aimed to examine the needs and attitudes of GPs toward a Web-based mental health service for adolescents, and to identify the factors that may affect the provision of this type of service and likelihood of integration. Findings will inform the content and overall service design. GPs were interviewed individually about the proposed Web-based service. Qualitative analysis of transcripts was performed using thematic coding. A short follow-up questionnaire was delivered to assess background characteristics, level of acceptability, and likelihood of integration of the Web-based mental health service. A total of 13 GPs participated in the interview and 11 completed a follow-up online questionnaire. Findings suggest strong support for the proposed Web-based mental health service. A wide range of factors were found to influence the likelihood of GPs integrating a Web-based service into their clinical practice. Coordinated collaboration with parents, students, school counselors, and other mental health care professionals were considered important by nearly all GPs. Confidence in Web-based care, noncompliance of adolescents and GPs, accessibility, privacy, and confidentiality were identified as potential barriers to adopting the proposed Web-based service. GPs were open to a proposed Web-based service for the monitoring and management of anxiety and depression in adolescents, provided that a collaborative approach to care is used, the feedback regarding the client is clear, and privacy and security provisions are assured. ©Mirjana Subotic-Kerry, Catherine King, Kathleen O'Moore, Melinda Achilles, Bridianne O'Dea. Originally published in JMIR Human Factors (http://humanfactors.jmir.org), 23.03.2018.

Social Support and HIV Risks Among Migrant and Non-Migrant Market Workers in Almaty, Kazakhstan.

PubMed

Mergenova, Gaukhar; Shaw, Stacey A; Terlikbayeva, Assel; Gilbert, Louisa; Gensburg, Lenore; Primbetova, Sholpan; El-Bassel, Nabila

2017-08-01

Migration processes are listed within the primary factors facilitating the heterosexual spread of HIV. The study examines the relationship between social support, sexual HIV risk behaviors and sexually transmitted infections (STIs) among 1342 male migrant and non-migrant market workers from Barakholka Market in Almaty, Kazakhstan. (1) higher level of perceived social support [Enhancing Recovery in Coronary Heart Disease (ENRICHD) Social Support Instrument (ESSI score)] was associated with a lower likelihood of having sex with a female sex worker (FSW) [OR = 0.952 (0.927, 0.978) p < .001]; (2) higher availability of friends was associated with a higher likelihood of having STIs [OR = 1.244 (1.007, 1.537), p < .05]; (3) larger network size was associated with a higher likelihood of having STIs [OR = 1.201 (1.026, 1.407), p < .05]; (4) loneliness was associated with an increased likelihood of having unprotected sex with any female partner [RR = 1.102 (1.027, 1.182), p < .05]. Results suggest that social support factors should be considered as a component of HIV and STI prevention programs for male migrant workers from Central Asia in Kazakhstan.

Infertility Evaluation and Treatment among Women in the United States

PubMed Central

Kessler, Lawrence M.; Craig, Benjamin M.; Plosker, Shayne M.; Reed, Damon R.; Quinn, Gwendolyn P.

2013-01-01

Objective To examine the characteristics of women seeking infertility evaluation and treatment. Design Cross-sectional survey based on in-person interviews, followed by two-step hurdle analysis. Participants 4,558 married or cohabitating women ages 25–44 Setting U.S. household population of women based on the 2006–2010 National Survey of Family Growth Intervention None Main Outcome Measure(s) Likelihood of seeking preliminary infertility evaluation. Likelihood of seeking infertility treatment once evaluated. Treatment type provided. Results 623 women (13.7%) reported seeking infertility evaluation, of which 328 reported undergoing subsequent infertility treatment. Age at marriage, marital status, education, health insurance status, race/ethnicity, and religion were associated with the likelihood of seeking infertility evaluation. For example, the predicted probability that a non-White woman who married at 25 will seek evaluation was 12%. This probability increased to 34% for White women with a graduate degree who married at age 30. Among women who are evaluated, income, employment status, and ethnicity correlated strongly with the likelihood of seeking infertility treatment. Infertility drug therapy was the most frequent treatment used. Reproductive surgery and in vitro fertilization (IVF) were used the least. Conclusions The use of infertility services is not random and understanding the socio-demographic factors correlated with use may assist new couples with family planning. Roughly 50% of the women evaluated for infertility progressed to treatment, and only a small proportion were treated with more advanced assisted reproductive technologies (ARTs) such as IVF therapy. Future research aimed at improving access to effective healthcare treatments within the boundaries of affordability is warranted. PMID:23849845

Industry Perspective of Pediatric Drug Development in the United States: Involvement of the European Union Countries.

PubMed

Onishi, Taku; Tsukamoto, Katsura; Matsumaru, Naoki; Waki, Takashi

2018-01-01

Efforts to promote the development of pediatric pharmacotherapy include regulatory frameworks and close collaboration between the US Food and Drug Administration and the European Medicines Agency. We characterized the current status of pediatric clinical trials conducted in the United States by the pharmaceutical industry, focusing on the involvement of the European Union member countries, to clarify the industry perspective. Data on US pediatric clinical trials were obtained from ClinicalTrials.gov . Binary regression analysis was performed to identify what factors influence the likelihood of involvement of European Union countries. A total of 633 US pediatric clinical trials that met inclusion criteria were extracted and surveyed. Of these, 206 (32.5%) involved a European Union country site(s). The results of binary regression analysis indicated that attribution of industry, phase, disease area, and age of pediatric participants influenced the likelihood of the involvement of European Union countries in US pediatric clinical trials. Relatively complicated or large pediatric clinical trials, such as phase II and III trials and those that included a broad age range of participants, had a significantly greater likelihood of the involvement of European Union countries ( P < .05). Our results suggest that (1) the pharmaceutical industry utilizes regulatory frameworks in making business decisions regarding pediatric clinical trials, (2) disease area affects the involvement of European Union countries, and (3) feasibility of clinical trials is mainly concerned by pharmaceutical industry for pediatric drug development. Additional incentives for high marketability may further motivate pharmaceutical industry to develop pediatric drugs.

Adolescents' future orientation and nonmedical use of prescription drugs.

PubMed

Steiger, Rena M; Stoddard, Sarah A; Pierce, Jennifer

2017-02-01

How adolescents think about their future (i.e., future orientation) impacts their risk-taking behavior. The purpose of the present analysis was to explore whether future orientation (future planning, perceived risk to future goals, and positive future expectations) was associated with nonmedical use of stimulants and analgesics in a sample of high school students. Information on future orientation and nonmedical use of prescription drugs (NMUPD) were collected using a paper-and-pencil survey from a sample of 9th-12th grade students in a Midwestern school. Higher perceived risk to future goals and positive future expectations were associated with a lower likelihood of self-reported nonmedical use of stimulants (n=250; OR=0.46, 95% CI: 0.26, 0.83; OR=0.15, 95% CI: 0.05, 0.47, respectively). Only higher perceived risk to future goals was associated with a lower likelihood of self-reported nonmedical use of analgesics (n=250; OR=0.40, 95% CI: 0.24, 0.68). In a follow-up analysis limited to students who endorsed alcohol or marijuana use, perceived risk to future goals remained associated with a lower likelihood of nonmedical use of stimulants and analgesics. Results suggest that risk perception might be a salient protective factor against both nonmedical use of stimulants and analgesics. Overall, the differential impact of conceptualizations of future orientation might depend on the class of prescription drug used, demonstrating a need to consider prescription drugs individually in the development of future studies and interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cross-cultural differences for adapting overactive bladder symptoms: results of an epidemiologic survey in Korea.

PubMed

Choo, Myung-Soo; Ku, Ja Hyeon; Lee, Jong Bok; Lee, Dong Hwan; Kim, Joon Chul; Kim, Hyung-Jee; Lee, Jeong Ju; Park, Won-Hee

2007-10-01

The purpose of this study was to evaluate the prevalence of overactive bladder (OAB) in a Korean national community sample of adults aged 40-89 years. A national Korean telephone survey using quota sampling methods was conducted. A clinically validated computer-assisted telephone interview approach was used in the survey. In 2,005 subjects (1,005 women and 1,000 men) interviewed, the prevalence of OAB(wet) increased with age in both men and women but OAB(dry) did not. OAB(dry) of men and women was not different in each age decade but OAB(wet) was more common among women than men aged <70 years. Multivariate analysis indicated that sex, age and body mass index (BMI) were associated with OAB(dry). For OAB(wet), sex and age were independent risk factors but BMI was not. In multivariate analysis, urgency was not associated with an increased likelihood of the impact on sexual life in men. The likelihood of the impact on sexual life, quality of life (QOL) and willingness to seek medical consultation was not related to nocturia. In female subjects, odds ratios for the impact of daily living, sexual life, QOL, and willingness to seek help from a health professional were not increased for nocuria. The likelihood of the impact on sexual life and willingness to seek medical help was not related to urge incontinence. Our study provides a valuable insight into the need for tailored education to this population about OAB. These findings suggest that there are cross-cultural differences for adapting OAB symptoms.

[Methods of the multivariate statistical analysis of so-called polyetiological diseases using the example of coronary heart disease].

PubMed

Lifshits, A M

1979-01-01

General characteristics of the multivariate statistical analysis (MSA) is given. Methodical premises and criteria for the selection of an adequate MSA method applicable to pathoanatomic investigations of the epidemiology of multicausal diseases are presented. The experience of using MSA with computors and standard computing programs in studies of coronary arteries aterosclerosis on the materials of 2060 autopsies is described. The combined use of 4 MSA methods: sequential, correlational, regressional, and discriminant permitted to quantitate the contribution of each of the 8 examined risk factors in the development of aterosclerosis. The most important factors were found to be the age, arterial hypertension, and heredity. Occupational hypodynamia and increased fatness were more important in men, whereas diabetes melitus--in women. The registration of this combination of risk factors by MSA methods provides for more reliable prognosis of the likelihood of coronary heart disease with a fatal outcome than prognosis of the degree of coronary aterosclerosis.

Sex Education, Public Opinion, and Pornography: A Conditional Process Analysis.

PubMed

Wright, Paul J

2018-05-10

This study assesses the relationship between pornography consumption and support for sex education in public schools among adults in the United States. Goals were theoretical and applied. At the theoretical level, conditional process analyses are needed to further evaluate the predictions of the primary theory applied to pornography and social influence, the sexual script acquisition, activation, application model ( 3 AM) of sexual media socialization. At the applied level, themes in pornography are most often associated with socialization outcomes that are a threat to the public health. In certain instances, however, pornography may socialize its users in ways that lead to health-promoting attitudes. An increased likelihood of support for sex education among youth may be one such example. Probabilistic national survey data gathered between 1988 and 2016 from 16 unique samples were utilized. A moderated-mediation path analysis indicated that pornography consumption was associated with support for sex education through more acceptance of teenage sex, but that this indirect effect (IE) was moderated by religiosity. Specifically, as religiosity decreased, the magnitude of the IE increased. These results are consistent with 3 AM tenets about the role of sexual scripts in mass media socialization and factors that increase the likelihood of sexual scripting effects.

Organizational and environmental factors associated with nursing home participation in managed care.

PubMed Central

Zinn, J S; Mor, V; Castle, N; Intrator, O; Brannon, D

1999-01-01

OBJECTIVE: To develop and test a model, based on resource dependence theory, that identifies the organizational and environmental characteristics associated with nursing home participation in managed care. DATA SOURCES AND STUDY SETTING: Data for statistical analysis derived from a survey of Directors of Nursing in a sample of nursing homes in eight states (n = 308). These data were merged with data from the On-line Survey Certification and Reporting System, the Medicare Managed Care State/County Data File, and the 1995 Area Resource File. STUDY DESIGN: Since the dependent variable is dichotomous, the logistic procedure was used to fit the regression. The analysis was weighted using SUDAAN. FINDINGS: Participation in a provider network, higher proportions of resident care covered by Medicare, providing IV therapy, greater availability of RNs and physical therapists, and Medicare HMO market penetration are associated with a greater likelihood of having a managed care contract. CONCLUSION: As more Medicare recipients enroll in HMOs, nursing home involvement in managed care is likely to increase. Interorganizational linkages enhance the likelihood of managed care participation. Nursing homes interested in managed care should consider upgrading staffing and providing at least some subacute services. PMID:10029508

Root Cause Analysis: Learning from Adverse Safety Events.

PubMed

Brook, Olga R; Kruskal, Jonathan B; Eisenberg, Ronald L; Larson, David B

2015-10-01

Serious adverse events continue to occur in clinical practice, despite our best preventive efforts. It is essential that radiologists, both as individuals and as a part of organizations, learn from such events and make appropriate changes to decrease the likelihood that such events will recur. Root cause analysis (RCA) is a process to (a) identify factors that underlie variation in performance or that predispose an event toward undesired outcomes and (b) allow for development of effective strategies to decrease the likelihood of similar adverse events occurring in the future. An RCA process should be performed within the environment of a culture of safety, focusing on underlying system contributors and, in a confidential manner, taking into account the emotional effects on the staff involved. The Joint Commission now requires that a credible RCA be performed within 45 days for all sentinel or major adverse events, emphasizing the need for all radiologists to understand the processes with which an effective RCA can be performed. Several RCA-related tools that have been found to be useful in the radiology setting include the "five whys" approach to determine causation; cause-and-effect, or Ishikawa, diagrams; causal tree mapping; affinity diagrams; and Pareto charts. © RSNA, 2015.

Empirical Likelihood in Nonignorable Covariate-Missing Data Problems.

PubMed

Xie, Yanmei; Zhang, Biao

2017-04-20

Missing covariate data occurs often in regression analysis, which frequently arises in the health and social sciences as well as in survey sampling. We study methods for the analysis of a nonignorable covariate-missing data problem in an assumed conditional mean function when some covariates are completely observed but other covariates are missing for some subjects. We adopt the semiparametric perspective of Bartlett et al. (Improving upon the efficiency of complete case analysis when covariates are MNAR. Biostatistics 2014;15:719-30) on regression analyses with nonignorable missing covariates, in which they have introduced the use of two working models, the working probability model of missingness and the working conditional score model. In this paper, we study an empirical likelihood approach to nonignorable covariate-missing data problems with the objective of effectively utilizing the two working models in the analysis of covariate-missing data. We propose a unified approach to constructing a system of unbiased estimating equations, where there are more equations than unknown parameters of interest. One useful feature of these unbiased estimating equations is that they naturally incorporate the incomplete data into the data analysis, making it possible to seek efficient estimation of the parameter of interest even when the working regression function is not specified to be the optimal regression function. We apply the general methodology of empirical likelihood to optimally combine these unbiased estimating equations. We propose three maximum empirical likelihood estimators of the underlying regression parameters and compare their efficiencies with other existing competitors. We present a simulation study to compare the finite-sample performance of various methods with respect to bias, efficiency, and robustness to model misspecification. The proposed empirical likelihood method is also illustrated by an analysis of a data set from the US National Health and Nutrition Examination Survey (NHANES).

Assessing the Structure of the Ways of Coping Questionnaire in Fibromyalgia Patients Using Common Factor Analytic Approaches.

PubMed

Van Liew, Charles; Santoro, Maya S; Edwards, Larissa; Kang, Jeremy; Cronan, Terry A

2016-01-01

The Ways of Coping Questionnaire (WCQ) is a widely used measure of coping processes. Despite its use in a variety of populations, there has been concern about the stability and structure of the WCQ across different populations. This study examines the factor structure of the WCQ in a large sample of individuals diagnosed with fibromyalgia. The participants were 501 adults (478 women) who were part of a larger intervention study. Participants completed the WCQ at their 6-month assessment. Foundational factoring approaches were performed on the data (i.e., maximum likelihood factoring [MLF], iterative principal factoring [IPF], principal axis factoring (PAF), and principal components factoring [PCF]) with oblique oblimin rotation. Various criteria were evaluated to determine the number of factors to be extracted, including Kaiser's rule, Scree plot visual analysis, 5 and 10% unique variance explained, 70 and 80% communal variance explained, and Horn's parallel analysis (PA). It was concluded that the 4-factor PAF solution was the preferable solution, based on PA extraction and the fact that this solution minimizes nonvocality and multivocality. The present study highlights the need for more research focused on defining the limits of the WCQ and the degree to which population-specific and context-specific subscale adjustments are needed.

Assessing the Structure of the Ways of Coping Questionnaire in Fibromyalgia Patients Using Common Factor Analytic Approaches

PubMed Central

Edwards, Larissa; Kang, Jeremy

2016-01-01

The Ways of Coping Questionnaire (WCQ) is a widely used measure of coping processes. Despite its use in a variety of populations, there has been concern about the stability and structure of the WCQ across different populations. This study examines the factor structure of the WCQ in a large sample of individuals diagnosed with fibromyalgia. The participants were 501 adults (478 women) who were part of a larger intervention study. Participants completed the WCQ at their 6-month assessment. Foundational factoring approaches were performed on the data (i.e., maximum likelihood factoring [MLF], iterative principal factoring [IPF], principal axis factoring (PAF), and principal components factoring [PCF]) with oblique oblimin rotation. Various criteria were evaluated to determine the number of factors to be extracted, including Kaiser's rule, Scree plot visual analysis, 5 and 10% unique variance explained, 70 and 80% communal variance explained, and Horn's parallel analysis (PA). It was concluded that the 4-factor PAF solution was the preferable solution, based on PA extraction and the fact that this solution minimizes nonvocality and multivocality. The present study highlights the need for more research focused on defining the limits of the WCQ and the degree to which population-specific and context-specific subscale adjustments are needed. PMID:28070160

Examining the types and payments of the disabilities of the insurants in the National Farmers' Health Insurance program in Taiwan.

PubMed

Wang, Jiun-Hao; Chang, Hung-Hao

2010-10-26

In contrast to the considerable body of literature concerning the disabilities of the general population, little information exists pertaining to the disabilities of the farm population. Focusing on the disability issue to the insurants in the Farmers' Health Insurance (FHI) program in Taiwan, this paper examines the associations among socio-demographic characteristics, insured factors, and the introduction of the national health insurance program, as well as the types and payments of disabilities among the insurants. A unique dataset containing 1,594,439 insurants in 2008 was used in this research. A logistic regression model was estimated for the likelihood of received disability payments. By focusing on the recipients, a disability payment and a disability type equation were estimated using the ordinary least squares method and a multinomial logistic model, respectively, to investigate the effects of the exogenous factors on their received payments and the likelihood of having different types of disabilities. Age and different job categories are significantly associated with the likelihood of receiving disability payments. Compared to those under age 45, the likelihood is higher among recipients aged 85 and above (the odds ratio is 8.04). Compared to hired workers, the odds ratios for self-employed and spouses of farm operators who were not members of farmers' associations are 0.97 and 0.85, respectively. In addition, older insurants are more likely to have eye problems; few differences in disability types are related to insured job categories. Results indicate that older farmers are more likely to receive disability payments, but the likelihood is not much different among insurants of various job categories. Among all of the selected types of disability, a highest likelihood is found for eye disability. In addition, the introduction of the national health insurance program decreases the likelihood of receiving disability payments. The experience in Taiwan can be valuable for other countries that are in an initial stage to implement a universal health insurance program.

Predicting adolescent's cyberbullying behavior: A longitudinal risk analysis.

PubMed

Barlett, Christopher P

2015-06-01

The current study used the risk factor approach to test the unique and combined influence of several possible risk factors for cyberbullying attitudes and behavior using a four-wave longitudinal design with an adolescent US sample. Participants (N = 96; average age = 15.50 years) completed measures of cyberbullying attitudes, perceptions of anonymity, cyberbullying behavior, and demographics four times throughout the academic school year. Several logistic regression equations were used to test the contribution of these possible risk factors. Results showed that (a) cyberbullying attitudes and previous cyberbullying behavior were important unique risk factors for later cyberbullying behavior, (b) anonymity and previous cyberbullying behavior were valid risk factors for later cyberbullying attitudes, and (c) the likelihood of engaging in later cyberbullying behavior increased with the addition of risk factors. Overall, results show the unique and combined influence of such risk factors for predicting later cyberbullying behavior. Results are discussed in terms of theory. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Undernutrition among adults in India: the significance of individual-level and contextual factors impacting on the likelihood of underweight across sub-populations.

PubMed

Siddiqui, Md Zakaria; Donato, Ronald

2017-01-01

To investigate the extent to which individual-level as well as macro-level contextual factors influence the likelihood of underweight across adult sub-populations in India. Population-based cross-sectional survey included in India's National Health Family Survey conducted in 2005-06. We disaggregated into eight sub-populations. Multistage nationally representative household survey covering 99 % of India's population. The survey covered 124 385 females aged 15-49 years and 74 369 males aged 15-54 years. A social gradient in underweight exists in India. Even after allowing for wealth status, differences in the predicted probability of underweight persisted based upon rurality, age/maturity and gender. We found individual-level education lowered the likelihood of underweight for males, but no statistical association for females. Paradoxically, rural young (15-24 years) females from more educated villages had a higher likelihood of underweight relative to those in less educated villages; but for rural mature (>24 years) females the opposite was the case. Christians had a significantly lower likelihood of underweight relative to other socio-religious groups (OR=0·53-0·80). Higher state-level inequality increased the likelihood of underweight across most population groups, while neighbourhood inequality exhibited a similar relationship for the rural young population subgroups only. Individual states/neighbourhoods accounted for 5-9 % of the variation in the prediction of underweight. We found that rural young females represent a particularly highly vulnerable sub-population. Economic growth alone is unlikely to reduce the burden of malnutrition in India; accordingly, policy makers need to address the broader social determinants that contribute to higher underweight prevalence in specific demographic subgroups.

Neighborhood adversity, ethnic diversity, and weak social cohesion and social networks predict high rates of maternal depressive symptoms: a critical realist ecological study in South Western Sydney, Australia.

PubMed

Eastwood, John Graeme; Kemp, Lynn Ann; Jalaludin, Bin Badrudin; Phung, Hai Ngoc

2013-01-01

The aim of the study reported here is to explore ecological covariate and latent variable associations with perinatal depressive symptoms in South Western Sydney for the purpose of informing subsequent theory generation of perinatal context, depression, and the developmental origins of health and disease. Mothers (n = 15,389) delivering in 2002 and 2003 were assessed at two to three weeks after delivery for risk factors for depressive symptoms. The binary outcome variables were Edinburgh Postnatal Depression Scale (EPDS)> 9 and > 12. Aggregated EPDS > 9 was analyzed for 101 suburbs. Suburb-level variables were drawn from the 2001 Australian Census, New South Wales Crime Statistics, and aggregated individual-level risk factors. Analysis included exploratory factor analysis, univariate and multivariate likelihood, and Bayesian linear regression with conditional autoregressive components. The exploratory factor analysis identified six factors: neighborhood adversity, social cohesion, health behaviors, housing quality, social services, and support networks. Variables associated with neighborhood adversity, social cohesion, social networks, and ethnic diversity were consistently associated with aggregated depressive symptoms. The findings support the theoretical proposition that neighborhood adversity causes maternal psychological distress and depression within the context of social buffers including social networks, social cohesion, and social services.

Dual use of alcohol and marijuana and condomless sex in young adult men and women: A within-subject day-level analysis.

PubMed

Hayaki, Jumi; Anderson, Bradley J; Stein, Michael D

2018-06-20

Unprotected sex has been linked independently to alcohol and marijuana use, but few studies have examined associations with dual use or gender differences in these associations. This study examined day-level associations between unprotected sex, defined as condomless vaginal sex with an opposite-sex partner, and use of alcohol, marijuana, neither, or both substances among 290 young adults (18-25 years, 52.3% female) who reported either alcohol or marijuana use. Participants reported demographics, alcohol use, marijuana use, and at least one episode of condomless sex as defined above in the past 90 days (Timeline Follow-Back). The likelihood of condomless sex was examined for days when alcohol, marijuana, neither, or both were used. Gender differences were also explored. For females, compared to days with no substance use, the estimated risk of condomless sex increased by a factor of 2.12 on alcohol use days, 1.89 on marijuana use days, and 3.39 on dual use days. Among males, the odds of condomless sex increased only slightly on alcohol use (odds ratio [OR] = 1.03) or marijuana use (OR = 1.08) days, but increased by a factor of 1.71 on dual use days. Young persons who use alcohol and/or marijuana experience heightened likelihood of condomless sex. This increased likelihood is greater for women than for men on days with alcohol or marijuana use, each alone but especially when combined. Young women may be especially susceptible to the influence of alcohol and/or marijuana use on sexual behavior. (Am J Addict 2018;XX:1-6). © 2018 American Academy of Addiction Psychiatry.

Scale of Unpredictability Beliefs: Reliability and Validity.

PubMed

Ross, Lisa Thomson; Short, Stephen D; Garofano, Marina

2016-11-16

Experiencing unpredictability in the environment has a variety of negative outcomes. However, these are difficult to ascertain due to the lack of a psychometrically sound measure of unpredictability beliefs. This article summarizes the development of the Scale of Unpredictability Beliefs (SUB), which assesses perceptions about unpredictability in one's life, in other people, and in the world. In Study I, college students (N = 305) responded to 68 potential items as well as other scales. Exploratory factor analysis yielded three internally consistent subscales (Self, People, and World; 16 items total). Higher SUB scores correlated with more childhood family unpredictability, greater likelihood of parental alcohol abuse, stronger causal uncertainty, and lower self-efficacy. In Study II, a confirmatory factor analysis supported the three-factor solution (N = 186 college students). SUB scores correlated with personality, childhood family unpredictability, and control beliefs. In most instances the SUB predicted family unpredictability and control beliefs beyond existing unpredictability measures. Study III confirmed the factor structure and replicated family unpredictability associations in an adult sample (N = 483). This article provides preliminary support for this new multi-dimensional, self-report assessment of unpredictability beliefs, and ideas for future research are discussed.

COSMIC MICROWAVE BACKGROUND LIKELIHOOD APPROXIMATION FOR BANDED PROBABILITY DISTRIBUTIONS

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

Gjerløw, E.; Mikkelsen, K.; Eriksen, H. K.

We investigate sets of random variables that can be arranged sequentially such that a given variable only depends conditionally on its immediate predecessor. For such sets, we show that the full joint probability distribution may be expressed exclusively in terms of uni- and bivariate marginals. Under the assumption that the cosmic microwave background (CMB) power spectrum likelihood only exhibits correlations within a banded multipole range, Δl{sub C}, we apply this expression to two outstanding problems in CMB likelihood analysis. First, we derive a statistically well-defined hybrid likelihood estimator, merging two independent (e.g., low- and high-l) likelihoods into a single expressionmore » that properly accounts for correlations between the two. Applying this expression to the Wilkinson Microwave Anisotropy Probe (WMAP) likelihood, we verify that the effect of correlations on cosmological parameters in the transition region is negligible in terms of cosmological parameters for WMAP; the largest relative shift seen for any parameter is 0.06σ. However, because this may not hold for other experimental setups (e.g., for different instrumental noise properties or analysis masks), but must rather be verified on a case-by-case basis, we recommend our new hybridization scheme for future experiments for statistical self-consistency reasons. Second, we use the same expression to improve the convergence rate of the Blackwell-Rao likelihood estimator, reducing the required number of Monte Carlo samples by several orders of magnitude, and thereby extend it to high-l applications.« less

Program for Weibull Analysis of Fatigue Data

NASA Technical Reports Server (NTRS)

Krantz, Timothy L.

2005-01-01

A Fortran computer program has been written for performing statistical analyses of fatigue-test data that are assumed to be adequately represented by a two-parameter Weibull distribution. This program calculates the following: (1) Maximum-likelihood estimates of the Weibull distribution; (2) Data for contour plots of relative likelihood for two parameters; (3) Data for contour plots of joint confidence regions; (4) Data for the profile likelihood of the Weibull-distribution parameters; (5) Data for the profile likelihood of any percentile of the distribution; and (6) Likelihood-based confidence intervals for parameters and/or percentiles of the distribution. The program can account for tests that are suspended without failure (the statistical term for such suspension of tests is "censoring"). The analytical approach followed in this program for the software is valid for type-I censoring, which is the removal of unfailed units at pre-specified times. Confidence regions and intervals are calculated by use of the likelihood-ratio method.

Factors associated with sinus bradycardia during crizotinib treatment: a retrospective analysis of two large-scale multinational trials (PROFILE 1005 and 1007).

PubMed

Ou, Sai-Hong Ignatius; Tang, Yiyun; Polli, Anna; Wilner, Keith D; Schnell, Patrick

2016-04-01

Decreases in heart rate (HR) have been described in patients receiving crizotinib. We performed a large retrospective analysis of HR changes during crizotinib therapy. HRs from vital-sign data for patients with anaplastic lymphoma kinase (ALK)-positive nonsmall cell lung cancer enrolled in PROFILE 1005 and the crizotinib arm of PROFILE 1007 were analyzed. Sinus bradycardia (SB) was defined as HR <60 beats per minute (bpm). Magnitude and timing of HR changes were assessed. Potential risk factors for SB were investigated by logistic regression analysis. Progression-free survival (PFS) was evaluated according to HR decrease by <20 versus ≥ 20 bpm within the first 50 days of starting treatment. For the 1053 patients analyzed, the mean maximum postbaseline HR decrease was 25 bpm (standard deviation 15.8). Overall, 441 patients (41.9%) had at least one episode of postbaseline SB. The mean precrizotinib treatment HR was significantly lower among patients with versus without postbaseline SB (82.2 bpm vs. 92.6 bpm). The likelihood of experiencing SB was statistically significantly higher among patients with a precrizotinib treatment HR <70 bpm. PFS was comparable among patients with or without HR decrease of ≥ 20 bpm within the first 50 days of starting crizotinib. Decrease in HR is very common among patients on crizotinib. The likelihood of experiencing SB was statistically significantly higher among patients with a precrizotinib treatment HR <70 bpm. This is the first large-scale report investigating the association between treatment with a tyrosine kinase inhibitor and the development of bradycardia. HRs should be closely monitored during crizotinib treatment. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

An analysis from the Quality Outcomes Database, Part 2. Predictive model for return to work after elective surgery for lumbar degenerative disease.

PubMed

Asher, Anthony L; Devin, Clinton J; Archer, Kristin R; Chotai, Silky; Parker, Scott L; Bydon, Mohamad; Nian, Hui; Harrell, Frank E; Speroff, Theodore; Dittus, Robert S; Philips, Sharon E; Shaffrey, Christopher I; Foley, Kevin T; McGirt, Matthew J

2017-10-01

OBJECTIVE Current costs associated with spine care are unsustainable. Productivity loss and time away from work for patients who were once gainfully employed contributes greatly to the financial burden experienced by individuals and, more broadly, society. Therefore, it is vital to identify the factors associated with return to work (RTW) after lumbar spine surgery. In this analysis, the authors used data from a national prospective outcomes registry to create a predictive model of patients' ability to RTW after undergoing lumbar spine surgery for degenerative spine disease. METHODS Data from 4694 patients who underwent elective spine surgery for degenerative lumbar disease, who had been employed preoperatively, and who had completed a 3-month follow-up evaluation, were entered into a prospective, multicenter registry. Patient-reported outcomes-Oswestry Disability Index (ODI), numeric rating scale (NRS) for back pain (BP) and leg pain (LP), and EQ-5D scores-were recorded at baseline and at 3 months postoperatively. The time to RTW was defined as the period between operation and date of returning to work. A multivariable Cox proportional hazards regression model, including an array of preoperative factors, was fitted for RTW. The model performance was measured using the concordance index (c-index). RESULTS Eighty-two percent of patients (n = 3855) returned to work within 3 months postoperatively. The risk-adjusted predictors of a lower likelihood of RTW were being preoperatively employed but not working at the time of presentation, manual labor as an occupation, worker's compensation, liability insurance for disability, higher preoperative ODI score, higher preoperative NRS-BP score, and demographic factors such as female sex, African American race, history of diabetes, and higher American Society of Anesthesiologists score. The likelihood of a RTW within 3 months was higher in patients with higher education level than in those with less than high school-level education. The c-index of the model's performance was 0.71. CONCLUSIONS This study presents a novel predictive model for the probability of returning to work after lumbar spine surgery. Spine care providers can use this model to educate patients and encourage them in shared decision-making regarding the RTW outcome. This evidence-based decision support will result in better communication between patients and clinicians and improve postoperative recovery expectations, which will ultimately increase the likelihood of a positive RTW trajectory.

Associations between sleep duration and physical activity and dietary behaviors in Chinese adolescents: results from the Youth Behavioral Risk Factor Surveys of 2015.

PubMed

Gong, Qing Hai; Li, Hui; Zhang, Xiao Hong; Zhang, Tao; Cui, Jun; Xu, Guo Zhang

2017-09-01

To assess the association between sleep duration and physical activity and dietary behaviors among adolescents in a representative sample. The analysis was performed using data from the 2015 Ningbo Youth Risk Behavior Survey. Associations between physical activity and dietary behaviors and sleep duration were examined on weighted data using logistic regression. Of the 10726 students, roughly 40% reported sleep duration <8 h. Longer sleep duration was associated with higher likelihood of milk intake, fruit consumption, vegetable consumption, water consumption, moderate physical activity, and muscle-strengthening physical activity, and with a lower likelihood of cigarette use, alcohol use, sweets intake, Western fast food intake, and breakfast skipping. Insufficient sleep may be common among Chinese adolescents. Sleep duration was associated with dietary behaviors, physical activity, and other health-related behaviors. These findings suggest that sleep duration could be a potential target for many health-risk behaviors in young adolescents. Copyright © 2017. Published by Elsevier B.V.

Individual relocation decisions after tornadoes: a multi-level analysis.

PubMed

Cong, Zhen; Nejat, Ali; Liang, Daan; Pei, Yaolin; Javid, Roxana J

2018-04-01

This study examines how multi-level factors affected individuals' relocation decisions after EF4 and EF5 (Enhanced Fujita Tornado Intensity Scale) tornadoes struck the United States in 2013. A telephone survey was conducted with 536 respondents, including oversampled older adults, one year after these two disaster events. Respondents' addresses were used to associate individual information with block group-level variables recorded by the American Community Survey. Logistic regression revealed that residential damage and homeownership are important predictors of relocation. There was also significant interaction between these two variables, indicating less difference between homeowners and renters at higher damage levels. Homeownership diminished the likelihood of relocation among younger respondents. Random effects logistic regression found that the percentage of homeownership and of higher income households in the community buffered the effect of damage on relocation; the percentage of older adults reduced the likelihood of this group relocating. The findings are assessed from the standpoint of age difference, policy implications, and social capital and vulnerability. © 2018 The Author(s). Disasters © Overseas Development Institute, 2018.

Variable selection in semiparametric cure models based on penalized likelihood, with application to breast cancer clinical trials.

PubMed

Liu, Xiang; Peng, Yingwei; Tu, Dongsheng; Liang, Hua

2012-10-30

Survival data with a sizable cure fraction are commonly encountered in cancer research. The semiparametric proportional hazards cure model has been recently used to analyze such data. As seen in the analysis of data from a breast cancer study, a variable selection approach is needed to identify important factors in predicting the cure status and risk of breast cancer recurrence. However, no specific variable selection method for the cure model is available. In this paper, we present a variable selection approach with penalized likelihood for the cure model. The estimation can be implemented easily by combining the computational methods for penalized logistic regression and the penalized Cox proportional hazards models with the expectation-maximization algorithm. We illustrate the proposed approach on data from a breast cancer study. We conducted Monte Carlo simulations to evaluate the performance of the proposed method. We used and compared different penalty functions in the simulation studies. Copyright © 2012 John Wiley & Sons, Ltd.

Regret associated with the decision for breast reconstruction: the association of negative body image, distress and surgery characteristics with decision regret.

PubMed

Sheehan, Joanne; Sherman, Kerry A; Lam, Thomas; Boyages, John

2008-01-01

This study investigated the influence of psychosocial and surgical factors on decision regret among 123 women diagnosed with breast cancer who had undergone immediate (58%) or delayed (42%) breast reconstruction following mastectomy. The majority of participants (52.8%, n = 65) experienced no decision regret, 27.6% experienced mild regret and 19.5% moderate to strong regret. Bivariate analyses indicated that decision regret was associated with negative body image and psychological distress - intrusion and avoidance. There were no differences in decision regret either with respect to methods or timing patterns of reconstructive surgery. Multinominal logistic regression analysis showed that, when controlling for mood state and time since last reconstructive procedure, increases in negative body image were associated with increased likelihood of experiencing decision regret. These findings highlight the need for optimal input from surgeons and therapists in order to promote realistic expectations regarding the outcome of breast reconstruction and to reduce the likelihood of women experiencing decision regret.

Factors associated with the healing of complex surgical wounds in the breast and abdomen: retrospective cohort study

PubMed Central

Borges, Eline Lima; Pires, José Ferreira; Abreu, Mery Natali Silva; Lima, Vera Lúcia de Araújo; Silva, Patrícia Aparecida Barbosa; Soares, Sônia Maria

2016-01-01

ABSTRACT Objective: to estimate the healing rate of complex surgical wounds and its associated factors. Method: retrospective cohort study from 2003 to 2014 with 160 outpatients of a Brazilian university hospital. Data were obtained through consultation of the medical records. Survival function was estimated using the Kaplan-Meier method and Cox regression model to estimate the likelihood of the occurrence of healing. Results: the complex surgical wound healing rate was 67.8% (95% CI: 60.8-74.9). Factors associated with a higher likelihood of wound healing were segmentectomy/quadrantectomy surgery, consumption of more than 20 grams/day of alcohol, wound extent of less that 17.3 cm2 and the length of existence of the wound prior to outpatient treatment of less than 15 days, while the use of hydrocolloid covering and Marlex mesh were associated with a lower likelihood of healing. Conclusion: the wound healing rate was considered high and was associated with the type of surgical intervention, alcohol consumption, type of covering, extent and length of wound existence. Preventive measures can be implemented during the monitoring of the evolution of the complex surgical wound closure, with possibilities of intervention in the modifiable risk factors. PMID:27737379

Assessment of genetic and nongenetic interactions for the prediction of depressive symptomatology: an analysis of the Wisconsin Longitudinal Study using machine learning algorithms.

PubMed

Roetker, Nicholas S; Page, C David; Yonker, James A; Chang, Vicky; Roan, Carol L; Herd, Pamela; Hauser, Taissa S; Hauser, Robert M; Atwood, Craig S

2013-10-01

We examined depression within a multidimensional framework consisting of genetic, environmental, and sociobehavioral factors and, using machine learning algorithms, explored interactions among these factors that might better explain the etiology of depressive symptoms. We measured current depressive symptoms using the Center for Epidemiologic Studies Depression Scale (n = 6378 participants in the Wisconsin Longitudinal Study). Genetic factors were 78 single nucleotide polymorphisms (SNPs); environmental factors-13 stressful life events (SLEs), plus a composite proportion of SLEs index; and sociobehavioral factors-18 personality, intelligence, and other health or behavioral measures. We performed traditional SNP associations via logistic regression likelihood ratio testing and explored interactions with support vector machines and Bayesian networks. After correction for multiple testing, we found no significant single genotypic associations with depressive symptoms. Machine learning algorithms showed no evidence of interactions. Naïve Bayes produced the best models in both subsets and included only environmental and sociobehavioral factors. We found no single or interactive associations with genetic factors and depressive symptoms. Various environmental and sociobehavioral factors were more predictive of depressive symptoms, yet their impacts were independent of one another. A genome-wide analysis of genetic alterations using machine learning methodologies will provide a framework for identifying genetic-environmental-sociobehavioral interactions in depressive symptoms.

Factors predicting a home death among home palliative care recipients

PubMed Central

Ko, Ming-Chung; Huang, Sheng-Jean; Chen, Chu-Chieh; Chang, Yu-Ping; Lien, Hsin-Yi; Lin, Jia-Yi; Woung, Lin-Chung; Chan, Shang-Yih

2017-01-01

Abstract Awareness of factors affecting the place of death could improve communication between healthcare providers and patients and their families regarding patient preferences and the feasibility of dying in the preferred place. This study aimed to evaluate factors predicting home death among home palliative care recipients. This is a population-based study using a national representative sample retrieved from the National Health Insurance Research Database. Subjects receiving home palliative care, from 2010 to 2012, were analyzed to evaluate the association between a home death and various characteristics related to illness, individual, and health care utilization. A multiple-logistic regression model was used to assess the independent effect of various characteristics on the likelihood of a home death. The overall rate of a home death for home palliative care recipients was 43.6%. Age; gender; urbanization of the area where the patients lived; illness; the total number of home visits by all health care professionals; the number of home visits by nurses; utilization of nasogastric tube, endotracheal tube, or indwelling urinary catheter; the number of emergency department visits; and admission to intensive care unit in previous 1 year were not significantly associated with the risk of a home death. Physician home visits increased the likelihood of a home death. Compared with subjects without physician home visits (31.4%) those with 1 physician home visit (53.0%, adjusted odds ratio [AOR]: 3.23, 95% confidence interval [CI]: 1.93–5.42) and those with ≥2 physician home visits (43.9%, AOR: 2.23, 95% CI: 1.06–4.70) had higher likelihood of a home death. Compared with subjects with hospitalization 0 to 6 times in previous 1 year, those with hospitalization ≥7 times in previous 1 year (AOR: 0.57, 95% CI: 0.34–0.95) had lower likelihood of a home death. Among home palliative care recipients, physician home visits increased the likelihood of a home death. Hospitalizations ≥7 times in previous 1 year decreased the likelihood of a home death. PMID:29019887

Body weight concerns: Cross-national study and identification of factors related to eating disorders

PubMed Central

da Silva, Wanderson Roberto; Santana, Moema de Souza; Maroco, João; Maloa, Benvindo Felismino Samuel

2017-01-01

Background Body weight concerns are common among individuals with eating disorders, and this construct can be assessed using psychometric instruments. The Weight Concerns Scale (WCS) is commonly used to assess body weight concerns. Aims To evaluate the psychometric properties of the WCS with Brazilian, Portuguese, and Mozambican female college students; to estimate body weight concerns; and to identify factors related to eating disorders. Methods Confirmatory factor analysis was performed. Factorial, convergent, concurrent, and divergent validity, as well as reliability, were assessed. Cross-national invariance was tested by means of multigroup analysis. Structural models were tested using the WCS as the dependent variable, while demographic and academic variables and body mass index were used as independent variables. Logistic models were tested to estimate the likelihood of eating disorders being developed in specific groups. Results Participants were 2,068 female students. The psychometric properties of the WCS were adequate for the Portuguese sample; however, for the Brazilian and Mozambican samples, it was necessary to correlate the errors of two items to improve model fit. The WCS did not show cross-national invariance. The variables “thoughts about dropping out of college,” “medication use because of studies,” “medication and supplements use for body change,” “body mass index,” “socioeconomic status,” “age,” and “performance in course” were significant predictors of body weight concerns. Overall, 24.4% (95% confidence interval = 22.9–26.7) of the students were likely to develop eating disorders. Students under 21 years old, who use medication and supplements for body change, and who were classified as overweight/obese have increased likelihood of developing eating disorders. Conclusion The WCS showed good psychometric properties with Brazilian, Portuguese, and Mozambican students; however, it did not show cross-national invariance. We identified important aspects for investigating body weight concerns and factors related to eating disorders. PMID:28686602

SubspaceEM: A Fast Maximum-a-posteriori Algorithm for Cryo-EM Single Particle Reconstruction

PubMed Central

Dvornek, Nicha C.; Sigworth, Fred J.; Tagare, Hemant D.

2015-01-01

Single particle reconstruction methods based on the maximum-likelihood principle and the expectation-maximization (E–M) algorithm are popular because of their ability to produce high resolution structures. However, these algorithms are computationally very expensive, requiring a network of computational servers. To overcome this computational bottleneck, we propose a new mathematical framework for accelerating maximum-likelihood reconstructions. The speedup is by orders of magnitude and the proposed algorithm produces similar quality reconstructions compared to the standard maximum-likelihood formulation. Our approach uses subspace approximations of the cryo-electron microscopy (cryo-EM) data and projection images, greatly reducing the number of image transformations and comparisons that are computed. Experiments using simulated and actual cryo-EM data show that speedup in overall execution time compared to traditional maximum-likelihood reconstruction reaches factors of over 300. PMID:25839831

Family influences on adolescents' birth control and condom use, likelihood of sexually transmitted infections.

PubMed

Kao, Tsui-Sui Annie; Manczak, Melissa

2013-02-01

This study explored the relationships among personal factors, family structure and family function, adolescents' self-efficacy for safe sex, and sexual behaviors among sexually active adolescents. A subset sample from the first three waves of the National Longitudinal Study of Adolescent Health (Add Health) was selected for this exploratory secondary data analysis. Hierarchal and logistic regressions were conducted to explore the relationships among personal factors, family factors, and adolescents' self-reported sexually transmitted infections (STI) over time. Findings suggest that adolescents' racial/ethnic background, parents' disapproving attitudes, and family connectedness are significant predictors for birth control and condom use among adolescents. Although adolescents' personal factor and family structure play a role in their sexual behavior, positive family function significantly protects adolescents from STIs over time. School nurses can provide a vital point of care for at-risk adolescents by finding ways to encourage and incorporate parental and familial influences.

Parameter estimation in astronomy through application of the likelihood ratio. [satellite data analysis techniques

NASA Technical Reports Server (NTRS)

Cash, W.

1979-01-01

Many problems in the experimental estimation of parameters for models can be solved through use of the likelihood ratio test. Applications of the likelihood ratio, with particular attention to photon counting experiments, are discussed. The procedures presented solve a greater range of problems than those currently in use, yet are no more difficult to apply. The procedures are proved analytically, and examples from current problems in astronomy are discussed.

ATAC Autocuer Modeling Analysis.

DTIC Science & Technology

1981-01-01

the analysis of the simple rectangular scrnentation (1) is based on detection and estimation theory (2). This approach uses the concept of maximum ...continuous wave forms. In order to develop the principles of maximum likelihood, it is con- venient to develop the principles for the "classical...the concept of maximum likelihood is significant in that it provides the optimum performance of the detection/estimation problem. With a knowledge of

Occupational Violence and Aggression Experienced by Nursing and Caring Professionals.

PubMed

Shea, Tracey; Sheehan, Cathy; Donohue, Ross; Cooper, Brian; De Cieri, Helen

2017-03-01

To examine the extent and source of occupational violence and aggression (OVA) experienced by nursing and caring professionals. This study also examines the relative contributions of demographic characteristics and workplace and individual safety factors in predicting OVA. A cross-sectional study design with data collected using an online survey of employees in the nursing and caring professions in Victoria, Australia. Survey data collected from 4,891 members of the Australian Nursing and Midwifery Federation (Victorian branch) were analyzed using logistic regression. Sixty-seven percent of respondents reported experiencing OVA in the preceding 12 months, with nearly 20% experiencing OVA on a weekly or daily basis. The dominant sources of OVA were patients (79%) or relatives of patients (48%). Logistic regression analysis revealed that respondents working in public hospitals and aged care facilities were more likely to experience OVA, compared to those working in other workplaces. While higher levels of safety compliance reduced the likelihood of experiencing OVA, role overload and workplace safety factors such as prioritization of employee safety and leading indicators of occupational health and safety were stronger predictors. The likelihood of healthcare workers experiencing OVA varies across demographic and workplace characteristics. While some demographic characteristics and individual safety factors were significant predictors, our results suggest that a greater reduction in OVA could be achieved by improving workplace safety. The study's outcomes identify workforce segments that are most vulnerable to OVA. The study also highlights workplace safety factors such as the prioritization of employee safety that might assist in the reduction of OVA. © 2016 Sigma Theta Tau International.

Parental decisions following prenatal diagnosis of sex chromosome aneuploidy in Hong Kong.

PubMed

So, Po Lam; Cheng, Kwun Yue Yvonne; Cheuk, Kwan Yiu; Chiu, Wan Kam; Mak, Shui Lam; Mok, Sau Lan; Lo, Tsz Kin; Yung, Wai Kuen; Lo, Fai Man; Chung, Hon Yin Brian; Kan, Sik Yau Anita; Lee, Chin Peng; Tang, Hoi Yin Mary

2017-12-01

According to the published work, pregnancy termination rates due to prenatal diagnosis of fetal sex chromosome aneuploidies (SCA) vary widely. Some potentially modifiable and non-modifiable factors have been reported to be associated with parental decision. This study aimed to evaluate the rate of pregnancy termination for fetal SCA and the factors influencing parents' decisions in Hong Kong. This was a 21-year retrospective cohort study of parents' decisions following prenatal diagnosis of SCA. Univariate and multivariate analyses for the association between demographic factors, prenatal factors, or counseling provided and decision-making were conducted. The study included 399 pregnancies with prenatal diagnosis of SCA and the overall termination rate was 55.6% (91.7%, 48.0%, 23.4%, 4.8%, and 22.7% for 45,X, 47,XXY, 47,XXX, 47,XYY, and mosaicism, respectively). Pregnancies with ultrasound abnormalities were associated with higher termination rates than pregnancies with normal ultrasound findings (91.3% vs 28.3%, P < 0.0001). From multivariate regression analysis on 226 pregnancies with normal ultrasound examination, a higher likelihood to terminate was found in pregnancies affected by 45,X and 47,XXY (adjusted odds ratio, 4.72, P < 0.0001). Increased maternal age and history of infertility were associated with lower likelihood to terminate (adjusted odds ratio, 0.9, P = 0.012; and 5.12, P = 0.038, respectively). The pregnancy termination rate declined over time. A significant correlation was found between the termination of SCA-affected pregnancy and the presence of fetal sonographic abnormalities, type of SCA, maternal age, and presence of infertility. © 2017 Japan Society of Obstetrics and Gynecology.

Risk factors of patients with and without postoperative nausea (PON).

PubMed

Dienemann, Jacqueline; Hudgens, Amanda N; Martin, Dana; Jones, Holly; Hunt, Ronald; Blackwell, Richard; Norton, H James; Divine, George

2012-08-01

This purpose of this analysis was to study risk factors of postoperative nausea (PON) and their strength. Data were obtained during the screening phase of a controlled clinical trial of aromatherapy for PON. In a sample of 1151 postsurgical subjects, 301 (26.2%) reported PON. Significant risk factors identified in the order of odds ratios for nausea were female gender, gastrointestinal surgery, use of volatile anesthesia gases, history of PON, history of motion sickness, and use of opioids after surgery. Although still over 1.0, the risk factors of length of surgery over 1 hour and gynecologic surgery had the lowest odds ratios. Likelihood of nausea increased significantly with the number of significant risk factors (P<.0001). Administration of preventive antiemetic medication also increased with the number of significant risk factors (P<.0001). Among 301 subjects reporting nausea, 49 (16.28%) received preventive medication. Despite prevention efforts, PON remains a substantial side effect for many surgical patients. Copyright © 2012 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.

Longitudinal profiles of back pain across adulthood and their relationship with childhood factors: evidence from the 1946 British birth cohort

PubMed Central

Muthuri, Stella G.; Kuh, Diana; Cooper, Rachel

2018-01-01

Abstract This study aimed to (1) characterise long-term profiles of back pain across adulthood and (2) examine whether childhood risk factors were associated with these profiles, using data from 3271 participants in the Medical Research Council National Survey of Health and Development. A longitudinal latent class analysis was conducted on binary outcomes of back pain at ages 31, 36, 43, 53, 60 to 64, and 68 years. Multinomial logistic regression models were used to examine associations between selected childhood risk factors and class membership; adjusted for sex, adult body size, health status and behaviours, socioeconomic position, and family history of back pain. Four profiles of back pain were identified: no or occasional pain (57.7%), early-adulthood only (16.1%), mid-adulthood onset (16.9%), and persistent (9.4%). The “no or occasional” profile was treated as the referent category in subsequent analyses. After adjustment, taller height at age 7 years was associated with a higher likelihood of early-adulthood only (relative risk ratio per 1 SD increase in height = 1.31 [95% confidence interval: 1.05-1.65]) and persistent pain (relative risk ratio = 1.33 [95% confidence interval: 1.01-1.74]) in women (P for sex interaction = 0.01). Factors associated with an increased risk of persistent pain in both sexes were abdominal pain, poorest care in childhood, and poorer maternal health. Abdominal pain and poorest housing quality were also associated with an increased likelihood of mid-adulthood onset pain. These findings suggest that there are different long-term profiles of back pain, each of which is associated with different early life risk factors. This highlights the potential importance of early life interventions for the prevention and management of back pain. PMID:29408834

A characterization of factors determining postoperative ileus after laparoscopic colectomy enables the generation of a novel predictive score.

PubMed

Kronberg, Udo; Kiran, Ravi P; Soliman, Mohamed S M; Hammel, Jeff P; Galway, Ursula; Coffey, John Calvin; Fazio, Victor W

2011-01-01

Postoperative ileus (POI) after colorectal surgery is associated with prolonged hospital stay and increased costs. The aim of this study is to investigate pre-, intra-, and postoperative risk factors associated with the development of POI in patients undergoing laparoscopic partial colectomy. Patients operated between 2004 and 2008 were retrospectively identified from a prospectively maintained database, and clinical, metabolic, and pharmacologic data were obtained. Postoperative ileus was defined as the absence of bowel function for 5 or more days or the need for reinsertion of a nasogastric tube after starting oral diet in the absence of mechanical obstruction. Associations between likelihood of POI and study variables were assessed univariably by using χ tests, Fisher exact tests, and logistic regression models. A scoring system for prediction of POI was constructed by using a multivariable logistic regression model based on forward stepwise selection of preoperative factors. A total of 413 patients (mean age, 58 years; 53.5% women) were included, and 42 (10.2%) of them developed POI. Preoperative albumin, postoperative deep-vein thrombosis, and electrolyte levels were associated with POI. Age, previous abdominal surgery, and chronic preoperative use of narcotics were independently correlated with POI on multivariate analysis, which allowed the creation of a predictive score. Patients with a score of 2 or higher had an 18.3% risk of POI (P < 0.001). Postoperative ileus after laparoscopic partial colectomy is associated with specific preoperative and postoperative factors. The likelihood of POI can be predicted by using a preoperative scoring system. Addressing the postoperative factors may be expected to reduce the incidence of this common complication in high-risk patients.

From attitude to action: What shapes attitude toward walking to/from school and how does it influence actual behaviors?

PubMed

Yu, Chia-Yuan; Zhu, Xuemei

2016-09-01

Walking to/from school could promote children's physical activity and help combat childhood obesity. Parental attitudes have been identified as one of the important predictors. But it is unclear what factors shape parental attitudes, and how those in turn influence children's school travel. This study addresses this gap of knowledge by examining the mediating effect of parental attitudes for the relationships between personal, social, and built environmental factors and children's walking-to/from-school behaviors. Survey data (N=2597) were collected from 20 public elementary schools in Austin, Texas, measuring students' typical school travel mode; personal, social, and built environmental factors related to walking-to/from-school; and relevant parental attitudes. The analysis was conducted in M-plus 6.11 to test the proposed conceptual framework using a structural equation model (SEM). Parental attitudes showed significant mediating effects on walking-to/from-school behaviors. Older child, positive peer influence, walkable home-to-school distance, and favorable walking environments were associated with more enjoyment and lower attitudinal barriers, and in turn increased likelihood of walking to/from school. Being Hispanic, increased car ownership, and stronger traffic safety concerns reduced enjoyment and increased attitudinal barriers, and thus decreased likelihood of walking to/from school. This study highlighted the importance of using multilevel interventions to reduce attitudinal barriers and increase enjoyment of walking to/from school. Collaborations among different stakeholders are needed to address environmental issues (e.g., safety concerns) and social factors (e.g., peer influence), while being sensitive to personal factors (e.g., age, ethnicity, and car ownership). Copyright © 2016 Elsevier Inc. All rights reserved.

Bias correction in the hierarchical likelihood approach to the analysis of multivariate survival data.

PubMed

Jeon, Jihyoun; Hsu, Li; Gorfine, Malka

2012-07-01

Frailty models are useful for measuring unobserved heterogeneity in risk of failures across clusters, providing cluster-specific risk prediction. In a frailty model, the latent frailties shared by members within a cluster are assumed to act multiplicatively on the hazard function. In order to obtain parameter and frailty variate estimates, we consider the hierarchical likelihood (H-likelihood) approach (Ha, Lee and Song, 2001. Hierarchical-likelihood approach for frailty models. Biometrika 88, 233-243) in which the latent frailties are treated as "parameters" and estimated jointly with other parameters of interest. We find that the H-likelihood estimators perform well when the censoring rate is low, however, they are substantially biased when the censoring rate is moderate to high. In this paper, we propose a simple and easy-to-implement bias correction method for the H-likelihood estimators under a shared frailty model. We also extend the method to a multivariate frailty model, which incorporates complex dependence structure within clusters. We conduct an extensive simulation study and show that the proposed approach performs very well for censoring rates as high as 80%. We also illustrate the method with a breast cancer data set. Since the H-likelihood is the same as the penalized likelihood function, the proposed bias correction method is also applicable to the penalized likelihood estimators.

Neural Mechanisms for Integrating Prior Knowledge and Likelihood in Value-Based Probabilistic Inference

PubMed Central

Ting, Chih-Chung; Yu, Chia-Chen; Maloney, Laurence T.

2015-01-01

In Bayesian decision theory, knowledge about the probabilities of possible outcomes is captured by a prior distribution and a likelihood function. The prior reflects past knowledge and the likelihood summarizes current sensory information. The two combined (integrated) form a posterior distribution that allows estimation of the probability of different possible outcomes. In this study, we investigated the neural mechanisms underlying Bayesian integration using a novel lottery decision task in which both prior knowledge and likelihood information about reward probability were systematically manipulated on a trial-by-trial basis. Consistent with Bayesian integration, as sample size increased, subjects tended to weigh likelihood information more compared with prior information. Using fMRI in humans, we found that the medial prefrontal cortex (mPFC) correlated with the mean of the posterior distribution, a statistic that reflects the integration of prior knowledge and likelihood of reward probability. Subsequent analysis revealed that both prior and likelihood information were represented in mPFC and that the neural representations of prior and likelihood in mPFC reflected changes in the behaviorally estimated weights assigned to these different sources of information in response to changes in the environment. Together, these results establish the role of mPFC in prior-likelihood integration and highlight its involvement in representing and integrating these distinct sources of information. PMID:25632152

Use pattern and predictors of use of highly caffeinated energy drinks among South Korean adolescents: a study using the Health Belief Model.

PubMed

Ha, Dongmun; Song, Inmyung; Jang, Gyeongil; Lee, Eui-Kyung; Shin, Ju-Young

2017-09-24

Concerns about the use of highly caffeinated energy drinks among Korean adolescents remains. We compared adolescents' perceptions regarding the use of drinks to their behaviours and factors. A structured questionnaire based on the Health Belief Model was administered to 850 freshmen and sophomores at three high schools in Bucheon, South Korea. Benefits were defined as beneficial effects from the use of highly caffeinated energy drinks (eg, awakening from sleepiness) and harms as adverse effects of the drinks (eg, cardiac palpitation). Likelihood of action represents the likelihood of taking actions that are perceived to be more beneficial after comparison of the benefits and harms of caffeine use. Descriptive analysis was used to quantify the relationship between their beliefs about highly caffeinated energy drinks and their use. We conducted hierarchical logistic regression to compute ORs and 95% CIs for: (1) demographic factors, (2) health threat, (3) likelihood of action and (4) cues to act. Altogether, 833 students responded to the questionnaire (effective response rate=98.0%). About 63.0% reported use of highly caffeinated energy drinks and 35.2% had used them as needed and habitually. The more susceptible the respondents perceived themselves to be to the risk of using these drinks, the less likely they were to use them (OR: 0.73, 95% CI 0.50 to 1.06). The more severe the perception of a health threat, the less that perception was associated with use (OR: 0.44, 95% CI 0.29 to 0.67). Likelihood of action was the strongest predictor of use, explaining 12.5% in use. Benefits and harms (OR: 4.43, 95% CI 2.77 to 7.09; OR: 1.86, 95% CI 1.16 to 2.99) also were significant predictors. Enhancing adolescents' perceptions of benefits and harms regarding using highly caffeinated energy drinks could be an effective way to influence the use of these drinks. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Factors that predict the use or non-use of virtual dissection by high school biology teachers

NASA Astrophysics Data System (ADS)

Cockerham, William

2001-07-01

With the advent of computers into scholastic classrooms, virtual dissection has become a potential educational tool in high school biology lab settings. Utilizing non-experimental survey research methodology, this study attempted to identify factors that may influence high school biology teachers to use or not to use a virtual dissection. A 75-item research survey instrument consisting of both demographic background and Likert style questions was completed by 215 high school members of the National Association of Biology Teachers. The survey responses provided data to answer the research questions concerning the relationship between the likelihood of a high school biology teacher using a virtual dissection and a number of independent variables from the following three categories: (a) demographics, (b) attitude and experience, and (c) resources and support. These data also allowed for the determination of a demographic profile of the sample population. The demographic profile showed the sample population of high school biology teachers to be two-thirds female, mature, highly educated and very experienced. Analysis of variance and Pearson product moment correlational statistics were used to determine if there was a relationship between high school biology teachers' likelihood to use a virtual dissection and the independent variables. None of the demographic or resource and support independent variables demonstrated a strong relationship to the dependent variable of teachers' likelihood to use a virtual dissection. Three of the attitude and experience independent variables showed a statistically significant (p < .05) relationship to teachers' likelihood to use a virtual dissection: attitude toward virtual dissection, previous use of a virtual dissection and intention to use a real animal dissection. These findings may indicate that teachers are using virtual dissection as a supplement rather than a substitute. It appears that those concerned with promoting virtual dissection in high school biology classrooms will have to develop simulations that are more compelling to the teachers. Additionally, if science teacher organizations want to reduce the controversy surrounding dissection, they may need to re-visit their positions on the importance of real animal dissection.

Likelihood analysis of spatial capture-recapture models for stratified or class structured populations

USGS Publications Warehouse

Royle, J. Andrew; Sutherland, Christopher S.; Fuller, Angela K.; Sun, Catherine C.

2015-01-01

We develop a likelihood analysis framework for fitting spatial capture-recapture (SCR) models to data collected on class structured or stratified populations. Our interest is motivated by the necessity of accommodating the problem of missing observations of individual class membership. This is particularly problematic in SCR data arising from DNA analysis of scat, hair or other material, which frequently yields individual identity but fails to identify the sex. Moreover, this can represent a large fraction of the data and, given the typically small sample sizes of many capture-recapture studies based on DNA information, utilization of the data with missing sex information is necessary. We develop the class structured likelihood for the case of missing covariate values, and then we address the scaling of the likelihood so that models with and without class structured parameters can be formally compared regardless of missing values. We apply our class structured model to black bear data collected in New York in which sex could be determined for only 62 of 169 uniquely identified individuals. The models containing sex-specificity of both the intercept of the SCR encounter probability model and the distance coefficient, and including a behavioral response are strongly favored by log-likelihood. Estimated population sex ratio is strongly influenced by sex structure in model parameters illustrating the importance of rigorous modeling of sex differences in capture-recapture models.

Maximum likelihood decoding analysis of accumulate-repeat-accumulate codes

NASA Technical Reports Server (NTRS)

Abbasfar, A.; Divsalar, D.; Yao, K.

2004-01-01

In this paper, the performance of the repeat-accumulate codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. Some simple codes are shown that perform very close to Shannon limit with maximum likelihood decoding.

Inheritance of dermatoglyphic asymmetry and diversity traits in twins based on factor: variance decomposition analysis.

PubMed

Karmakar, Bibha; Malkin, Ida; Kobyliansky, Eugene

2013-06-01

Dermatoglyphic asymmetry and diversity traits from a large number of twins (MZ and DZ) were analyzed based on principal factors to evaluate genetic effects and common familial environmental influences on twin data by the use of maximum likelihood-based Variance decomposition analysis. Sample consists of monozygotic (MZ) twins of two sexes (102 male pairs and 138 female pairs) and 120 pairs of dizygotic (DZ) female twins. All asymmetry (DA and FA) and diversity of dermatoglyphic traits were clearly separated into factors. These are perfectly corroborated with the earlier studies in different ethnic populations, which indicate a common biological validity perhaps exists of the underlying component structures of dermatoglyphic characters. Our heritability result in twins clearly showed that DA_F2 is inherited mostly in dominant type (28.0%) and FA_F1 is additive (60.7%), but no significant difference in sexes was observed for these factors. Inheritance is also very prominent in diversity Factor 1, which is exactly corroborated with our previous findings. The present results are similar with the earlier results of finger ridge count diversity in twin data, which suggested that finger ridge count diversity is under genetic control.

Phylogenetic Factor Analysis.

PubMed

Tolkoff, Max R; Alfaro, Michael E; Baele, Guy; Lemey, Philippe; Suchard, Marc A

2018-05-01

Phylogenetic comparative methods explore the relationships between quantitative traits adjusting for shared evolutionary history. This adjustment often occurs through a Brownian diffusion process along the branches of the phylogeny that generates model residuals or the traits themselves. For high-dimensional traits, inferring all pair-wise correlations within the multivariate diffusion is limiting. To circumvent this problem, we propose phylogenetic factor analysis (PFA) that assumes a small unknown number of independent evolutionary factors arise along the phylogeny and these factors generate clusters of dependent traits. Set in a Bayesian framework, PFA provides measures of uncertainty on the factor number and groupings, combines both continuous and discrete traits, integrates over missing measurements and incorporates phylogenetic uncertainty with the help of molecular sequences. We develop Gibbs samplers based on dynamic programming to estimate the PFA posterior distribution, over 3-fold faster than for multivariate diffusion and a further order-of-magnitude more efficiently in the presence of latent traits. We further propose a novel marginal likelihood estimator for previously impractical models with discrete data and find that PFA also provides a better fit than multivariate diffusion in evolutionary questions in columbine flower development, placental reproduction transitions and triggerfish fin morphometry.

Doping Attitudes and Covariates of Potential Doping Behaviour in High-Level Team-Sport Athletes; Gender Specific Analysis

PubMed Central

Sekulic, Damir; Tahiraj, Enver; Zvan, Milan; Zenic, Natasa; Uljevic, Ognjen; Lesnik, Blaz

2016-01-01

Team sports are rarely studied with regard to doping behaviour and doping-related factors regardless of their global popularity. This study aimed to investigate doping factors and covariates of potential doping behaviour in high-level team-sport athletes. The subjects were 457 high-performing, national- and international-level athletes (21.9 ± 3.4 years of age; 179 females) involved in volleyball (n = 77), soccer (n = 163), basketball (n = 114) and handball (n = 103). Previously validated self-administered questionnaires aimed at evidencing sport factors, doping-related factors, knowledge on sport nutrition and doping, and attitudes to performance enhancement were used. The results indicated a higher doping likelihood in male athletes, with a significant gender difference for basketball and handball. In males, a higher doping likelihood is found for athletes who had achieved better results at junior-age level, those who regularly consume dietary supplements, and who perceive their sport as being contaminated by doping. A higher sport achievement at senior-age level is protective against potential doping behaviour in males. In females, a higher likelihood of doping is evidenced in those athletes involved in binge drinking, while a lower tendency for doping is evidenced in female athletes who possess better knowledge on sport nutrition. Knowledge about doping is very low and thus education about doping is urgently needed. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in females. Future studies should consider other approaches and theories, such as theory of planned behaviour and/or social-cognitive theory, in studying the problem of doping behaviour in team-sports. Key points The doping knowledge among Kosovar team-sport athletes is very low and systematic anti-doping education is urgently needed. The highest risk of doping behaviour in males is found for those athletes who had been successful in their junior age and those who consume dietary supplements. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in female team-sport athletes. While the associations between the studied factors and doping behaviour are different between males and females, the gender-specific approach to exploring the covariates of doping behaviour is warranted. PMID:27928206

Factors associated with high-quality/low-cost hospital performance.

PubMed

Jiang, H Joanna; Friedman, Bernard; Begun, James W

2006-01-01

This study explores organizational and market characteristics associated with superior hospital performance in both quality and cost of care, using the Healthcare Cost and Utilization Project State Inpatient Databases for ten states in 1997 and 2001. After controlling for a variety of patient factors, we found that for-profit ownership, hospital competition, and the number of HMOs were positively associated with the likelihood of attaining high-quality/low-cost performance. Furthermore, we examined interactions between organizational and market characteristics and identified a number of significant interactions. For example, the positive likelihood associated with for-profit hospitals diminished in markets with high HMO penetration.

Univariate and bivariate likelihood-based meta-analysis methods performed comparably when marginal sensitivity and specificity were the targets of inference.

PubMed

Dahabreh, Issa J; Trikalinos, Thomas A; Lau, Joseph; Schmid, Christopher H

2017-03-01

To compare statistical methods for meta-analysis of sensitivity and specificity of medical tests (e.g., diagnostic or screening tests). We constructed a database of PubMed-indexed meta-analyses of test performance from which 2 × 2 tables for each included study could be extracted. We reanalyzed the data using univariate and bivariate random effects models fit with inverse variance and maximum likelihood methods. Analyses were performed using both normal and binomial likelihoods to describe within-study variability. The bivariate model using the binomial likelihood was also fit using a fully Bayesian approach. We use two worked examples-thoracic computerized tomography to detect aortic injury and rapid prescreening of Papanicolaou smears to detect cytological abnormalities-to highlight that different meta-analysis approaches can produce different results. We also present results from reanalysis of 308 meta-analyses of sensitivity and specificity. Models using the normal approximation produced sensitivity and specificity estimates closer to 50% and smaller standard errors compared to models using the binomial likelihood; absolute differences of 5% or greater were observed in 12% and 5% of meta-analyses for sensitivity and specificity, respectively. Results from univariate and bivariate random effects models were similar, regardless of estimation method. Maximum likelihood and Bayesian methods produced almost identical summary estimates under the bivariate model; however, Bayesian analyses indicated greater uncertainty around those estimates. Bivariate models produced imprecise estimates of the between-study correlation of sensitivity and specificity. Differences between methods were larger with increasing proportion of studies that were small or required a continuity correction. The binomial likelihood should be used to model within-study variability. Univariate and bivariate models give similar estimates of the marginal distributions for sensitivity and specificity. Bayesian methods fully quantify uncertainty and their ability to incorporate external evidence may be useful for imprecisely estimated parameters. Copyright © 2017 Elsevier Inc. All rights reserved.

Use of a brief version of the self-compassion inventory with an international sample of people with HIV/AIDS

PubMed Central

Brion, John M.; Leary, Mark; Wantland, Dean; Sullivan, K.; Nokes, Kathleen; Bain, Catherine A; Chaiphibalsarisdi, Puangtip; Chen, Wei-ti; Holzemer, William L.; Eller, Lucille Sanzero; Iipinge, Scholastika; Johnson, Mallory O.; Portillo, Carmen; Voss, Joachim; Tyer-Viola, Lynda; Corless, Inge B; Nicholas, Patrice K; Rose, Carol Dawson; Phillips, J. Craig; Sefcik, Elizabeth; Mendez, Marta Rivero; Kirksey, Kenn M.

2013-01-01

The objective of this study was to extend the psychometric evaluation of a brief version of the Self Compassion Scale (SCS). A secondary analysis of data from an international sample of 1,967 English-speaking persons living with HIV disease was used to examine the factor structure, and reliability of the 12-item Brief Version Self Compassion Inventory (BVSCI). A Maximum Likelihood factor analysis and Oblimin with Kaiser Normalization confirmed a two-factor solution, accounting for 42.58% of the variance. The BVSCI supported acceptable internal consistencies, with .714 for the total scale and .822 for Factor I and .774 for Factor II. Factor I (lower self compassion) demonstrated strongly positive correlations with measures of anxiety and depression while Factor II (high self compassion) was inversely correlated with the measures. No significant differences were found in the BVSCI scores for gender, age, or having children. Levels of self-compassion were significantly higher in persons with HIV disease and other physical and psychological health conditions. The scale shows promise for the assessment of self-compassion in persons with HIV without taxing participants, and may prove essential in investigating future research aimed at examining correlates of self-compassion, as well as providing data for tailoring self-compassion interventions for persons with HIV. PMID:23527887

Analysis of Factors Influencing Diagnostic Accuracy of T-SPOT.TB for Active Tuberculosis in Clinical Practice.

PubMed

Zhang, Lifan; Shi, Xiaochun; Zhang, Yueqiu; Zhang, Yao; Huo, Feifei; Zhou, Baotong; Deng, Guohua; Liu, Xiaoqing

2017-08-10

T-SPOT.TB didn't perform a perfect diagnosis for active tuberculosis (ATB), and some factors may influence the results. We did this study to evaluate possible factors associated with the sensitivity and specificity of T-SPOT.TB, and the diagnostic parameters under varied conditions. Patients with suspected ATB were enrolled prospectively. Influencing factors of the sensitivity and specificity of T-SPOT.TB were evaluated using logistic regression models. Sensitivity, specificity, predictive values (PV), and likelihood ratios (LR) were calculated with consideration of relevant factors. Of the 865 participants, 205 (23.7%) had ATB, including 58 (28.3%) microbiologically confirmed TB and 147 (71.7%) clinically diagnosed TB. 615 (71.7%) were non-TB. 45 (5.2%) cases were clinically indeterminate and excluded from the final analysis. In multivariate analysis, serous effusion was the only independent risk factor related to lower sensitivity (OR = 0.39, 95% CI: 0.18-0.81) among patients with ATB. Among non-TB patients, age, TB history, immunosuppressive agents/glucocorticoid treatment and lymphocyte count were the independent risk factors related to specificity of T-SPOT.TB. Sensitivity, specificity, PV+, PV-, LR+ and LR- of T-SPOT.TB for diagnosis of ATB were 78.5%, 74.1%, 50.3%, 91.2%, 3.0 and 0.3, respectively. This study suggests that influencing factors of sensitivity and specificity of T-SPOT.TB should be considered for interpretation of T-SPOT.TB results.

Endoscopic ultrasound-guided fine needle core biopsy for the diagnosis of pancreatic malignant lesions: a systematic review and Meta-Analysis

PubMed Central

Yang, Yongtao; Li, Lianyong; Qu, Changmin; Liang, Shuwen; Zeng, Bolun; Luo, Zhiwen

2016-01-01

Endoscopic ultrasound-guided fine needle core biopsy (EUS-FNB) has been used as an effective method of diagnosing pancreatic malignant lesions. It has the advantage of providing well preserved tissue for histologic grading and subsequent molecular biological analysis. In order to estimate the diagnostic accuracy of EUS-FNB for pancreatic malignant lesions, studies assessing EUS-FNB to diagnose solid pancreatic masses were selected via Medline. Sixteen articles published between 2005 and 2015, covering 828 patients, met the inclusion criteria. The summary estimates for EUS-FNB differentiating malignant from benign solid pancreatic masses were: sensitivity 0.84 (95% confidence interval (CI), 0.82–0.87); specificity 0.98 (95% CI, 0.93–1.00); positive likelihood ratio 8.0 (95% CI 4.5–14.4); negative likelihood ratio 0.17 (95% CI 0.10–0.26); and DOR 64 (95% CI 30.4–134.8). The area under the sROC curve was 0.96. Subgroup analysis did not identify other factors that could substantially affect the diagnostic accuracy, such as the study design, location of study, number of centers, location of lesion, whether or not a cytopathologist was present, and so on. EUS-FNB is a reliable diagnostic tool for solid pancreatic masses and should be especially considered for pathology where histologic morphology is preferred for diagnosis. PMID:26960914

A Comparative Study of Behavior Problems among Left-Behind Children, Migrant Children and Local Children.

PubMed

Hu, Hongwei; Gao, Jiamin; Jiang, Haochen; Jiang, Haixia; Guo, Shaoyun; Chen, Kun; Jin, Kaili; Qi, Yingying

2018-04-01

This study aims to estimate the prevalence of behavioral problems among left-behind children, migrant children and local children in China, and to compare the risks of behavioral problems among the three types of children. Data on 4479 children aged 6-16 used in this study were from a survey conducted in China in 2017. The school-age version of the Children Behavior Checklist was used to measure children's behavioral problems. Descriptive analysis, correlation analysis, and logistic regressions were conducted. The prevalence of behavioral problems was 18.80% and 13.59% for left-behind children and migrant children, respectively, both of which were higher than that of local children. Logistic regression analysis showed that after adjustments for individual and environmental variables, the likelihood of total, internalizing and externalizing behavior problems for left-behind children and migrant children were higher than those for local children; left-behind children had a higher likelihood of internalizing problems than externalizing problems, while migrant children had a higher prevalence of externalizing problems. Left-behind children had a higher prevalence of each specific syndrome than migrant and local children. Both individual and environmental factors were associated with child behavioral problems, and family migration may contribute to the increased risks. Left-behind and migrant children were more vulnerable than local children to behavioral problems.

A Comparative Study of Behavior Problems among Left-Behind Children, Migrant Children and Local Children

PubMed Central

Hu, Hongwei; Gao, Jiamin; Jiang, Haochen; Jiang, Haixia; Guo, Shaoyun; Chen, Kun; Jin, Kaili; Qi, Yingying

2018-01-01

This study aims to estimate the prevalence of behavioral problems among left-behind children, migrant children and local children in China, and to compare the risks of behavioral problems among the three types of children. Data on 4479 children aged 6–16 used in this study were from a survey conducted in China in 2017. The school-age version of the Children Behavior Checklist was used to measure children’s behavioral problems. Descriptive analysis, correlation analysis, and logistic regressions were conducted. The prevalence of behavioral problems was 18.80% and 13.59% for left-behind children and migrant children, respectively, both of which were higher than that of local children. Logistic regression analysis showed that after adjustments for individual and environmental variables, the likelihood of total, internalizing and externalizing behavior problems for left-behind children and migrant children were higher than those for local children; left-behind children had a higher likelihood of internalizing problems than externalizing problems, while migrant children had a higher prevalence of externalizing problems. Left-behind children had a higher prevalence of each specific syndrome than migrant and local children. Both individual and environmental factors were associated with child behavioral problems, and family migration may contribute to the increased risks. Left-behind and migrant children were more vulnerable than local children to behavioral problems. PMID:29614783

Chemical information obtained from Auger depth profiles by means of advanced factor analysis (MLCFA)

NASA Astrophysics Data System (ADS)

De Volder, P.; Hoogewijs, R.; De Gryse, R.; Fiermans, L.; Vennik, J.

1993-01-01

The advanced multivariate statistical technique "maximum likelihood common factor analysis (MLCFA)" is shown to be superior to "principal component analysis (PCA)" for decomposing overlapping peaks into their individual component spectra of which neither the number of components nor the peak shape of the component spectra is known. An examination of the maximum resolving power of both techniques, MLCFA and PCA, by means of artificially created series of multicomponent spectra confirms this finding unambiguously. Substantial progress in the use of AES as a chemical-analysis technique is accomplished through the implementation of MLCFA. Chemical information from Auger depth profiles is extracted by investigating the variation of the line shape of the Auger signal as a function of the changing chemical state of the element. In particular, MLCFA combined with Auger depth profiling has been applied to problems related to steelcord-rubber tyre adhesion. MLCFA allows one to elucidate the precise nature of the interfacial layer of reaction products between natural rubber vulcanized on a thin brass layer. This study reveals many interesting chemical aspects of the oxi-sulfidation of brass undetectable with classical AES.

Risk analysis of gravity dam instability using credibility theory Monte Carlo simulation model.

PubMed

Xin, Cao; Chongshi, Gu

2016-01-01

Risk analysis of gravity dam stability involves complicated uncertainty in many design parameters and measured data. Stability failure risk ratio described jointly by probability and possibility has deficiency in characterization of influence of fuzzy factors and representation of the likelihood of risk occurrence in practical engineering. In this article, credibility theory is applied into stability failure risk analysis of gravity dam. Stability of gravity dam is viewed as a hybrid event considering both fuzziness and randomness of failure criterion, design parameters and measured data. Credibility distribution function is conducted as a novel way to represent uncertainty of influence factors of gravity dam stability. And combining with Monte Carlo simulation, corresponding calculation method and procedure are proposed. Based on a dam section, a detailed application of the modeling approach on risk calculation of both dam foundation and double sliding surfaces is provided. The results show that, the present method is feasible to be applied on analysis of stability failure risk for gravity dams. The risk assessment obtained can reflect influence of both sorts of uncertainty, and is suitable as an index value.

Measurement of CIB power spectra with CAM-SPEC from Planck HFI maps

NASA Astrophysics Data System (ADS)

Mak, Suet Ying; Challinor, Anthony; Efstathiou, George; Lagache, Guilaine

2015-08-01

We present new measurements of the cosmic infrared background (CIB) anisotropies and its first likelihood using Planck HFI data at 353, 545, and 857 GHz. The measurements are based on cross-frequency power spectra and likelihood analysis using the CAM-SPEC package, rather than map based template removal of foregrounds as done in previous Planck CIB analysis. We construct the likelihood of the CIB temperature fluctuations, an extension of CAM-SPEC likelihood as used in CMB analysis to higher frequency, and use it to drive the best estimate of the CIB power spectrum over three decades in multiple moment, l, covering 50 ≤ l ≤ 2500. We adopt parametric models of the CIB and foreground contaminants (Galactic cirrus, infrared point sources, and cosmic microwave background anisotropies), and calibrate the dataset uniformly across frequencies with known Planck beam and noise properties in the likelihood construction. We validate our likelihood through simulations and extensive suite of consistency tests, and assess the impact of instrumental and data selection effects on the final CIB power spectrum constraints. Two approaches are developed for interpreting the CIB power spectrum. The first approach is based on simple parametric model which model the cross frequency power using amplitudes, correlation coefficients, and known multipole dependence. The second approach is based on the physical models for galaxy clustering and the evolution of infrared emission of galaxies. The new approaches fit all auto- and cross- power spectra very well, with the best fit of χ2ν = 1.04 (parametric model). Using the best foreground solution, we find that the cleaned CIB power spectra are in good agreement with previous Planck and Herschel measurements.

Handwriting individualization using distance and rarity

NASA Astrophysics Data System (ADS)

Tang, Yi; Srihari, Sargur; Srinivasan, Harish

2012-01-01

Forensic individualization is the task of associating observed evidence with a specific source. The likelihood ratio (LR) is a quantitative measure that expresses the degree of uncertainty in individualization, where the numerator represents the likelihood that the evidence corresponds to the known and the denominator the likelihood that it does not correspond to the known. Since the number of parameters needed to compute the LR is exponential with the number of feature measurements, a commonly used simplification is the use of likelihoods based on distance (or similarity) given the two alternative hypotheses. This paper proposes an intermediate method which decomposes the LR as the product of two factors, one based on distance and the other on rarity. It was evaluated using a data set of handwriting samples, by determining whether two writing samples were written by the same/different writer(s). The accuracy of the distance and rarity method, as measured by error rates, is significantly better than the distance method.

The influence of fatness on the likelihood of early-winter pregnancy in muskoxen (Ovibos moschatus).

PubMed

Adamczewski, J Z; Fargey, P J; Laarveld, B; Gunn, A; Flood, P F

1998-09-01

Among wild ruminants, muskoxen have an exceptional ability to fatten, but their pregnancy rates are variable and often low. To test whether the likelihood of pregnancy in muskoxen is associated with exceptionally good body condition, we used logistic regression analysis with data from 32 pregnant and 18 nonpregnant muskoxen > or = 1.5 yr of age shot in November (1989 to 1992) on Victoria Island in Arctic Canada. We assayed their serum for insulin-like growth factor-1 (IGF-1). All fatness and mass measures were positively related to the likelihood of pregnancy (P < 0.001), with the strongest associations for estimated total fat mass (80% of outcomes predicted correctly) and kidney fat mass (77%), and weaker models for body mass. Pregnancy was less likely to occur in lactating females than in nonlactating ones (P = 0.03). Although IGF-1 concentrations were higher (P = 0.001) in nonlactating females than in lactating ones (28.7 +/- 1.7 vs. 22.5 ng/ml), no association with pregnancy was detected (P = 0.57). Fatness associated with a 50% probability of pregnancy in muskoxen (22% of ingesta-free body mass or 32 kg fat in females > 3.5 yr old) is much higher than in caribou and somewhat higher than in cattle, and this may partly account for the low calving rates often observed in this species.

The Role of Gender and Physical Performance on Injuries: An Army Study.

PubMed

Anderson, Morgan K; Grier, Tyson; Dada, Esther O; Canham-Chervak, Michelle; Jones, Bruce H

2017-05-01

In basic combat training, women experience twice as many injuries as men; however, evidence at the operational Army level is limited. This study aims to investigate the association between gender and injury likelihood while controlling for certain confounding factors in the operational Army. Data were analyzed in 2015 from a cross-sectional study utilizing data from a 2010-2011 survey of light infantry Army Soldiers. Gender, age, body fat, tobacco use, Army Physical Fitness Test (2-mile run, push-ups, and sit-ups), occupational physical demand, and injury data were obtained via paper survey. ORs and 95% CIs from a multivariable analysis were calculated. Surveys were completed by 4,384 male and 363 female Soldiers. Injury incidence was 42% for men and 53% for women. After adjusting for the aforementioned variables, injury likelihood was higher in Soldiers aged ≥27 years (OR [age 27-29/22-26 years]=1.26, 95% CI=1.07, 1.48; OR [age ≥30/22-26 years]=1.28, 95% CI=1.08, 1.51), Soldiers with body fat ≥23.38% (OR [body fat ≥23.38%/≤19.28%]=1.30, 95% CI=1.08, 1.57), and Soldiers with the slowest 2-mile run times (OR [≥15.68/≤14.13 minutes]=1.53, 95% CI=1.26, 1.85). Women were no more likely than men to sustain an injury. When accounting for age, body fat, physical performance, and occupational physical demand, there was no gender difference in the likelihood of injury among Soldiers. Although women, on average, have lower aerobic and muscular performance than men, results suggest men and women of similar physical performance experience similar injury likelihood. Copyright © 2016. Published by Elsevier Inc.

Analysis of Hospital Readmission Patterns in Medicare Fee-for-Service and Medicare Advantage Beneficiaries.

PubMed

Oh, Joobong June Park

The study was conducted to examine the hospital readmission patterns of two groups of Medicare beneficiaries-those covered by traditional Medicare (Medicare fee-for-service [FFS]) and those enrolled in a Medicare risk plan (Medicare Advantage [MA])-and to determine the characteristics that significantly increase the likelihood of multiple hospital readmissions. The study setting is the Hospital of the University of Pennsylvania (HUP) located in Philadelphia, PA. A retrospective descriptive study design was used to analyze the electronic data from the HUP information technology system for Medicare beneficiaries, 65 years and older, who had an index hospital admission at the HUP during 2012 (January 1, 2012, through December 31, 2012), and were subsequently readmitted one or more times to the HUP during the observation period. FFS and MA beneficiaries were hospitalized an average of 1.5 (±1.0) times; 69% were rehospitalized once and 30% were rehospitalized two or more times. Characteristics that increased the likelihood of multiple hospital readmissions included being discharged on a weekend, admitted through the emergency department with a diagnosis of injury and poisoning, being diagnosed with a new problem of the circulatory system, having an exacerbation of a circulatory system illness, and having an infection related to a previous admission. Characteristics that decreased the likelihood of multiple hospital readmissions included being discharged to a skilled nursing facility and being discharged home with home health services. Identification of the risk factors and characteristics that increase the likelihood of multiple hospital readmissions will permit early interventions in discharge planning, as evidenced by decreasing the rate of hospital readmissions and the length of hospital stays, increasing in time to hospital readmission, and preventing the first readmission and a subsequent return to the hospital.

Orbitofrontal cortex and drug use during adolescence: role of prenatal exposure to maternal smoking and BDNF genotype.

PubMed

Lotfipour, Shahrdad; Ferguson, Eamonn; Leonard, Gabriel; Perron, Michel; Pike, Bruce; Richer, Louis; Séguin, Jean R; Toro, Roberto; Veillette, Suzanne; Pausova, Zdenka; Paus, Tomás

2009-11-01

Prenatal exposure to maternal cigarette smoking (PEMCS) may affect brain development and behavior in adolescent offspring. To evaluate the involvement of the orbitofrontal cortex (OFC) in mediating the relationship between PEMCS and substance use. Cross-sectional analyses from the Saguenay Youth Study aimed at evaluating the effects of PEMCS on brain development and behavior among adolescents. Nonexposed adolescents were matched with adolescents exposed prenatally to cigarette smoking by maternal educational level. A French Canadian founder population of the Saguenay-Lac-Saint-Jean region of Quebec, Canada. The behavioral data set included 597 adolescents (275 sibships; 12-18 years of age), half of whom were exposed in utero to maternal cigarette smoking. Analysis of cortical thickness and genotyping were performed using available data from 314 adolescents. The likelihood of substance use was assessed with the Diagnostic Interview Schedule for Children Predictive Scales. The number of different drugs tried by each adolescent was assessed using another questionnaire. Thickness of the OFC was estimated from T1-weighted magnetic resonance images using FreeSurfer software. Prenatal exposure to maternal cigarette smoking is associated with an increased likelihood of substance use. Among exposed adolescents, the likelihood of drug experimentation correlates with the degree of OFC thinning. In nonexposed adolescents, the thickness of the OFC increases as a function of the number of drugs tried. The latter effect is moderated by a brain-derived neurotrophic factor (BDNF) genotype (Val66Met). We speculate that PEMCS interferes with the development of the OFC and, in turn, increases the likelihood of drug use among adolescents. In contrast, we suggest that, among nonexposed adolescents, drug experimentation influences the OFC thickness via processes akin to experience-induced plasticity.

Acceleration and sensitivity analysis of lattice kinetic Monte Carlo simulations using parallel processing and rate constant rescaling

NASA Astrophysics Data System (ADS)

Núñez, M.; Robie, T.; Vlachos, D. G.

2017-10-01

Kinetic Monte Carlo (KMC) simulation provides insights into catalytic reactions unobtainable with either experiments or mean-field microkinetic models. Sensitivity analysis of KMC models assesses the robustness of the predictions to parametric perturbations and identifies rate determining steps in a chemical reaction network. Stiffness in the chemical reaction network, a ubiquitous feature, demands lengthy run times for KMC models and renders efficient sensitivity analysis based on the likelihood ratio method unusable. We address the challenge of efficiently conducting KMC simulations and performing accurate sensitivity analysis in systems with unknown time scales by employing two acceleration techniques: rate constant rescaling and parallel processing. We develop statistical criteria that ensure sufficient sampling of non-equilibrium steady state conditions. Our approach provides the twofold benefit of accelerating the simulation itself and enabling likelihood ratio sensitivity analysis, which provides further speedup relative to finite difference sensitivity analysis. As a result, the likelihood ratio method can be applied to real chemistry. We apply our methodology to the water-gas shift reaction on Pt(111).

Factors associated with the initiation of disease-modifying antirheumatic drugs in newly diagnosed rheumatoid arthritis: a retrospective claims database study.

PubMed

Bonafede, Machaon M K; Fox, Kathleen M; Johnson, Barbara H; Watson, Crystal; Gandra, Shravanthi R

2012-02-01

The objectives of this study were to quantify the proportion of US patients with newly diagnosed rheumatoid arthritis (RA) in whom disease-modifying antirheumatic drug (DMARD) therapy was initiated within 12 months following diagnosis, to determine mean time to initiation, to compare the characteristics of initiators versus noninitiators, and to identify factors associated with noninitiation. A retrospective study was conducted using claims from the databases of commercial managed care and Medicare supplemental managed care to identify patients with claims containing codes for RA dated January 1, 2004, through September 30, 2008. The percentage of patients with RA and a prescription for a DMARD within 12 months after the index date (initiators) was evaluated. The characteristics of DMARD initiators and noninitiators during the preindex period were compared, including demographic and clinical characteristics, health care resource utilization, and cost variables. The probability of DMARD initiation was determined using survival analysis. Multivariate analysis was performed to estimate mean time from diagnosis to DMARD initiation based on demographic and clinical variables. Of 26,911 patients with newly diagnosed RA identified in the database searches, 63% had been prescribed a DMARD within 12 months after diagnosis. DMARD initiators were significantly more likely to have had a rheumatologist visit and rheumatoid factor testing and were more likely to have received a corticosteroid and/or an NSAID (all, P < 0.001). DMARD initiators had significantly lower total costs ($10,534 vs $12,725, respectively) and pharmacy drug costs ($2438 vs $2822) over the preindex period compared with noninitiators (both, P < 0.001). Independent factors associated with a greater likelihood of DMARD initiation included a rheumatologist visit, rheumatoid factor testing, NSAID use, and corticosteroid use. Age ≥85 years and the presence of comorbidities were associated with a significantly lower likelihood of DMARD initiation. Among managed care enrollees in the present analysis, 37% of patients newly diagnosed with RA were not being treated with DMARDs in the first 12 months after diagnosis. Time to DMARD initiation plateaued after 90 days, suggesting that if a patient was not prescribed a DMARD soon after RA diagnosis, he or she was not likely to receive one. Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.

Cross-sectional study of female sex workers in Soweto, South Africa: Factors associated with HIV infection

PubMed Central

2017-01-01

Introduction In South Africa, the rate of HIV in the sex worker (SW) population is exceedingly high, but critical gaps exist in our understanding of SWs and the factors that make them vulnerable to HIV. This study aimed to estimate HIV prevalence among female sex workers (FSWs) in Soweto, South Africa, and to describe their sexual behavior and other factors associated with HIV infection. Methods A cross-sectional, respondent-driven sampling (RDS) recruitment methodology was used to enroll 508 FSWs based in Soweto. Data were collected using a survey instrument, followed by two HIV rapid tests. Raw and RDS adjusted data were analyzed using a chi-squared test of association and multivariate logistic regression to show factors associated with HIV infection. Findings HIV prevalence among FSWs was 53.6% (95% CI 47.5–59.9). FSWs were almost exclusively based in taverns (85.6%) and hostels (52.0%). Less than a quarter (24.4%) were under 25 years of age. Non-partner violence was reported by 55.5%, 59.6% of whom were HIV-infected. Advancing age, incomplete secondary schooling, migrancy and multiple clients increased the likelihood of HIV acquisition: >30 years of age was associated with a 4.9 times (95% CI 2.6–9.3) increased likelihood of HIV; incomplete secondary schooling almost tripled the likelihood (AOR 2.8, 95% CI 1.6–5.0); being born outside of the Gauteng province increased the likelihood of HIV 2.3 times (95% CI 1.3–4.0); and having more than five clients per day almost doubled the likelihood (AOR 1.9, 95% CI 1.1–3.2). Conclusion Our findings highlight the extreme vulnerability of FSWs to HIV. Advancing age, limited education and multiple clients were risk factors associated with HIV, strongly driven by a combination of structural, biological and behavioral determinants. Evidence suggests that interventions need to be carefully tailored to the varying profiles of SW populations across South Africa. Soweto could be considered a microcosm of South Africa in terms of the epidemic of violence and HIV experienced by the SW population, which is influenced by factors often beyond an individual level of control. While describing a hitherto largely undocumented population of FSWs, our findings confirm the urgent need to scale up innovative HIV prevention and treatment programs for this population. PMID:28981511

Intensity of Care at the End of Life Among Older Adults in Korea.

PubMed

Kim, Su Hyun; Kang, Sangwook; Song, Mi-Kyung

2018-01-01

To examine the intensity of care at the end of life among older adults in Korea and to identify the individual and institutional factors associated with care intensity. This secondary data analysis included a sample of 6278 decedents aged 65 years or older who were identified from the 2009 to 2010 Korean National Health Insurance Service-National Sample Cohort Claims data. We examined the medical care received by the cohort in the last 30 days of their lives. Overall, 36.5% of the sample received at least 1 intensive care procedure in the last 30 days of their lives; 26.3% of patients experienced intensive care unit admission, with an average stay of 7.45 days, 19.5% received mechanical ventilation, 12.3% received cardiopulmonary resuscitation, and 15.5% had a feeding tube placement. A statistical analysis using a multiple logistic regression model with random effects showed that younger age, higher household income, primary diagnoses of diseases (ischemic heart disease, infectious disease, chronic lung disease, or chronic heart disease), and characteristics of care setting (large hospitals and facilities located in metropolitan areas) were significantly associated with the likelihood of receiving high-intensity care at the end of life. A substantial number of older adults in Korea experienced high-intensity end-of-life care. Both individual and institutional factors were associated with the likelihood of receiving high-intensity care. Gaining an understanding of the intensity of care at the end of life and the impact of the determinants would advance efforts to improve quality of care at the end of life for older adults in Korea.

Opting for rural practice: the influence of medical student origin, intention and immersion experience.

PubMed

Playford, Denese; Ngo, Hanh; Gupta, Surabhi; Puddey, Ian B

2017-08-21

To compare the influence of rural background, rural intent at medical school entry, and Rural Clinical School (RCS) participation on the likelihood of later participation in rural practice. Analysis of linked data from the Medical School Outcomes Database Commencing Medical Students Questionnaire (CMSQ), routinely collected demographic information, and the Australian Health Practitioner Regulation Agency database on practice location. University of Western Australia medical students who completed the CMSQ during 2006-2010 and were practising medicine in 2016. Medical practice in rural areas (ASGC-RAs 2-5) during postgraduate years 2-5. Full data were available for 508 eligible medical graduates. Rural background (OR, 3.91; 95% CI, 2.12-7.21; P < 0.001) and experience in an RCS (OR, 1.93; 95% CI, 1.05-3.54; P = 0.034) were significant predictors of rural practice in the multivariate analysis of all potential factors. When interactions between intention, origin, and RCS experience were included, RCS participation significantly increased the likelihood of graduates with an initial rural intention practising in a rural location (OR, 3.57; 95% CI, 1.25-10.2; P = 0.017). The effect of RCS participation was not significant if there was no pre-existing intention to practise rurally (OR, 1.38; 95% CI, 0.61-3.16; P = 0.44). For students who entered medical school with the intention to later work in a rural location, RCS experience was the deciding factor for realising this intention. Background, intent and RCS participation should all be considered if medical schools are to increase the proportion of graduates working rurally.

Pharmacists subjected to disciplinary action: characteristics and risk factors.

PubMed

Phipps, Denham L; Noyce, Peter R; Walshe, Kieran; Parker, Dianne; Ashcroft, Darren M

2011-10-01

OBJECTIVE To establish whether there are any characteristics of pharmacists that predict their likelihood of being subjected to disciplinary action. METHODS  The setting was the Royal Pharmaceutical Society of Great Britain's Disciplinary Committee. One hundred and seventeen pharmacists, all of whom had been referred to the Disciplinary Committee, were matched with a quota sample of 580 pharmacists who had not been subjected to disciplinary action but that matched the disciplined pharmacists on a set of demographic factors (gender, country of residence, year of registration). Frequency analysis and regression analysis were used to compare the two groups of pharmacists in terms of sector of work, ethnicity, age and country of training. Descriptive statistics were also obtained from the disciplined pharmacists to further explore characteristics of disciplinary cases and those pharmacists who undergo them. KEY FINDINGS  While a number of characteristics appeared to increase the likelihood of a pharmacist being referred to the disciplinary committee, only one of these - working in a community pharmacy - was statistically significant. Professional misconduct accounted for a greater proportion of referrals than did clinical malpractice, and approximately one-fifth of pharmacists who went before the Disciplinary Committee had previously been disciplined by the Society. CONCLUSIONS  This study provides initial evidence of pharmacist characteristics that are associated with an increased risk of being disciplined, based upon the data currently available. It is recommended that follow-up work is carried out using a more extensive dataset in order to confirm the statistical trends identified here. © 2011 The Authors. IJPP © 2011 Royal Pharmaceutical Society.

Environmental And Psychological Correlates of Older Adult’s Active Commuting

PubMed Central

Panter, Jenna; Jones, Andrew; van Sluijs, Esther; Griffin, Simon; Wareham, Nicholas

2013-01-01

Purpose This study explored the environmental and psychological correlates of active commuting in a sample of adults from the European Prospective Investigation into Cancer (EPIC) Norfolk cohort. Methods Members of the cohort who were in employment, lived within 10km of work, and did not report a limitation that precluded walking were included in this analysis. Psychological factors, perceptions of the neighbourhood environment and travel mode to work were reported using questionnaires. Neighbourhood and route environmental characteristics were estimated objectively using a Geographical Information System. The mediating effects of psychological factors were assessed using a series of regression models. Results 1279 adults (mean age of 60.4 years SD=5.4) were included in this analysis, of which, 25% actively commuted to work. In multivariable regression analyses, those who reported strong habits for walking or cycling were more likely to actively commute, whilst those living 4-10km from work were less likely to actively commute. In addition, living in a rural area was associated with a decreased likelihood of men’s active commuting and in women, living in a neighbourhood with high road density and having a route to work which was not on a main or secondary road was associated with an increased likelihood of active commuting. There was weak evidence that habit acted to partly mediate the associations between environmental correlates and active commuting in both sexes. Conclusions The findings suggest that interventions designed to encourage the development of habitual behaviours for active commuting may be effective, especially amongst those living close to work. PMID:21131863

A panel data analysis of the probability of childbirth in a Japanese sample: New evidence of the two-child norm.

PubMed

Morita, Masahito; Ohtsuki, Hisashi; Hiraiwa-Hasegawa, Mariko

2016-01-01

To reveal the conditions that could facilitate childbirth in modern humans, it is necessary to analyze not only cross-sectional surveys but also panel data that track the same person for a long period. In this study, we analyzed factors that would influence the probability of childbirth. We analyzed Japanese panel data with a Cox proportional hazard model. Subjects of our analysis were married women and their childbirth records from 2004 to 2009. Contrary to the predictions based on the theory of behavioral ecology, we found no positive relationship between good parental conditions for childcare, such as high income, increase in income, or coresidence with parents (i.e., grandparents of children), and the occurrence of childbirth. We found that the number of existing children had a significant impact on the probability of childbirth. The likelihood of further childbirth by couples with one child was nearly equal to that of childless ones. However, the corresponding likelihood of couples with two children was about five times lower than that of childless ones. The total fertility rates in modern developed societies are quite low and couples prefer having two children. This trend is known as the two-child norm, but it is a paradoxical phenomenon in terms of fitness maximization. Our result provided new quantitative evidence of this norm. This study revealed that the number of existing children being less than two was one of the factors associated with further childbearing in our Japanese sample. © 2015 Wiley Periodicals, Inc.

Artificial pancreas (AP) clinical trial participants' acceptance of future AP technology.

PubMed

Bevier, Wendy C; Fuller, Serena M; Fuller, Ryan P; Rubin, Richard R; Dassau, Eyal; Doyle, Francis J; Jovanovič, Lois; Zisser, Howard C

2014-09-01

Artificial pancreas (AP) systems are currently an active field of diabetes research. This pilot study examined the attitudes of AP clinical trial participants toward future acceptance of the technology, having gained firsthand experience. After possible influencers of AP technology adoption were considered, a 34-question questionnaire was developed. The survey assessed current treatment satisfaction, dimensions of clinical trial participant motivation, and variables of the technology acceptance model (TAM). Forty-seven subjects were contacted to complete the survey. The reliability of the survey scales was tested using Cronbach's α. The relationship of the factors to the likelihood of AP technology adoption was explored using regression analysis. Thirty-six subjects (76.6%) completed the survey. Of the respondents, 86.1% were either highly likely or likely to adopt the technology once available. Reliability analysis of the survey dimensions revealed good internal consistency, with scores of >0.7 for current treatment satisfaction, convenience (motivation), personal health benefit (motivation), perceived ease of use (TAM), and perceived usefulness (TAM). Linear modeling showed that future acceptance of the AP was significantly associated with TAM and the motivation variables of convenience plus the individual item benefit to others (R(2)=0.26, P=0.05). When insulin pump and continuous glucose monitor use were added, the model significance improved (R(2)=0.37, P=0.02). This pilot study demonstrated that individuals with direct AP technology experience expressed high likelihood of future acceptance. Results support the factors of personal benefit, convenience, perceived usefulness, and perceived ease of use as reliable scales that suggest system adoption in this highly motivated patient population.

Local environmental quality positively predicts breastfeeding in the UK's Millennium Cohort Study.

PubMed

Brown, Laura J; Sear, Rebecca

2017-01-01

Background and Objectives: Breastfeeding is an important form of parental investment with clear health benefits. Despite this, rates remain low in the UK; understanding variation can therefore help improve interventions. Life history theory suggests that environmental quality may pattern maternal investment, including breastfeeding. We analyse a nationally representative dataset to test two predictions: (i) higher local environmental quality predicts higher likelihood of breastfeeding initiation and longer duration; (ii) higher socioeconomic status (SES) provides a buffer against the adverse influences of low local environmental quality. Methodology: We ran factor analysis on a wide range of local-level environmental variables. Two summary measures of local environmental quality were generated by this analysis-one 'objective' (based on an independent assessor's neighbourhood scores) and one 'subjective' (based on respondent's scores). We used mixed-effects regression techniques to test our hypotheses. Results: Higher objective, but not subjective, local environmental quality predicts higher likelihood of starting and maintaining breastfeeding over and above individual SES and area-level measures of environmental quality. Higher individual SES is protective, with women from high-income households having relatively high breastfeeding initiation rates and those with high status jobs being more likely to maintain breastfeeding, even in poor environmental conditions. Conclusions and Implications: Environmental quality is often vaguely measured; here we present a thorough investigation of environmental quality at the local level, controlling for individual- and area-level measures. Our findings support a shift in focus away from individual factors and towards altering the landscape of women's decision making contexts when considering behaviours relevant to public health.

A Walk on the Wild Side: The Impact of Music on Risk-Taking Likelihood.

PubMed

Enström, Rickard; Schmaltz, Rodney

2017-01-01

From a marketing perspective, there has been substantial interest in on the role of risk-perception on consumer behavior. Specific 'problem music' like rap and heavy metal has long been associated with delinquent behavior, including violence, drug use, and promiscuous sex. Although individuals' risk preferences have been investigated across a range of decision-making situations, there has been little empirical work demonstrating the direct role music may have on the likelihood of engaging in risky activities. In the exploratory study reported here, we assessed the impact of listening to different styles of music while assessing risk-taking likelihood through a psychometric scale. Risk-taking likelihood was measured across ethical, financial, health and safety, recreational and social domains. Through the means of a canonical correlation analysis, the multivariate relationship between different music styles and individual risk-taking likelihood across the different domains is discussed. Our results indicate that listening to different types of music does influence risk-taking likelihood, though not in areas of health and safety.

A Walk on the Wild Side: The Impact of Music on Risk-Taking Likelihood

PubMed Central

Enström, Rickard; Schmaltz, Rodney

2017-01-01

From a marketing perspective, there has been substantial interest in on the role of risk-perception on consumer behavior. Specific ‘problem music’ like rap and heavy metal has long been associated with delinquent behavior, including violence, drug use, and promiscuous sex. Although individuals’ risk preferences have been investigated across a range of decision-making situations, there has been little empirical work demonstrating the direct role music may have on the likelihood of engaging in risky activities. In the exploratory study reported here, we assessed the impact of listening to different styles of music while assessing risk-taking likelihood through a psychometric scale. Risk-taking likelihood was measured across ethical, financial, health and safety, recreational and social domains. Through the means of a canonical correlation analysis, the multivariate relationship between different music styles and individual risk-taking likelihood across the different domains is discussed. Our results indicate that listening to different types of music does influence risk-taking likelihood, though not in areas of health and safety. PMID:28539908

Tests for detecting overdispersion in models with measurement error in covariates.

PubMed

Yang, Yingsi; Wong, Man Yu

2015-11-30

Measurement error in covariates can affect the accuracy in count data modeling and analysis. In overdispersion identification, the true mean-variance relationship can be obscured under the influence of measurement error in covariates. In this paper, we propose three tests for detecting overdispersion when covariates are measured with error: a modified score test and two score tests based on the proposed approximate likelihood and quasi-likelihood, respectively. The proposed approximate likelihood is derived under the classical measurement error model, and the resulting approximate maximum likelihood estimator is shown to have superior efficiency. Simulation results also show that the score test based on approximate likelihood outperforms the test based on quasi-likelihood and other alternatives in terms of empirical power. By analyzing a real dataset containing the health-related quality-of-life measurements of a particular group of patients, we demonstrate the importance of the proposed methods by showing that the analyses with and without measurement error correction yield significantly different results. Copyright © 2015 John Wiley & Sons, Ltd.

Foreground effect on the J-factor estimation of classical dwarf spheroidal galaxies

NASA Astrophysics Data System (ADS)

Ichikawa, Koji; Ishigaki, Miho N.; Matsumoto, Shigeki; Ibe, Masahiro; Sugai, Hajime; Hayashi, Kohei; Horigome, Shun-ichi

2017-07-01

The gamma-ray observation of the dwarf spheroidal galaxies (dSphs) is a promising approach to search for the dark matter annihilation (or decay) signal. The dSphs are the nearby satellite galaxies with a clean environment and dense dark matter halo so that they give stringent constraints on the O(1) TeV dark matter. However, recent studies have revealed that current estimation of astrophysical factors relevant for the dark matter searches are not conservative, where the various non-negligible systematic uncertainties are not taken into account. Among them, the effect of foreground stars on the astrophysical factors has not been paid much attention, which becomes more important for deeper and wider stellar surveys in the future. In this article, we assess the effects of the foreground contamination by generating the mock samples of stars and using a model of future spectrographs. We investigate various data cuts to optimize the quality of the data and find that the cuts on the velocity and surface gravity can efficiently eliminate the contamination. We also propose a new likelihood function that includes the foreground distribution function. We apply this likelihood function to the fit of the three types of the mock data (Ursa Minor, Draco with large dark matter halo and Draco with small halo) and three cases of the observation. The likelihood successfully reproduces the input J-factor value while the fit without considering the foreground distribution gives a large deviation from the input value by a factor of 3.

Treatment Recommendations for Single-Unit Crowns: Findings from The National Dental Practice-Based Research Network

PubMed Central

McCracken, Michael S.; Louis, David R.; Litaker, Mark S.; Minyé, Helena M.; Mungia, Rahma; Gordan, Valeria V.; Marshall, Don G.; Gilbert, Gregg H.

2016-01-01

Background Objectives were to: (1) quantify practitioner variation in likelihood to recommend a crown; and (2) test whether certain dentist, practice, and clinical factors are significantly associated with this likelihood. Methods Dentists in the National Dental Practice-Based Research Network completed a questionnaire about indications for single-unit crowns. In four clinical scenarios, practitioners ranked their likelihood of recommending a single-unit crown. These responses were used to calculate a dentist-specific “Crown Factor” (CF; range 0–12). A higher score implies a higher likelihood to recommend a crown. Certain characteristics were tested for statistically significant associations with the CF. Results 1,777 of 2,132 eligible dentists responded (83%). Practitioners were most likely to recommend crowns for teeth that were fractured, cracked, endodontically-treated, or had a broken restoration. Practitioners overwhelmingly recommended crowns for posterior teeth treated endodontically (94%). Practice owners, Southwest practitioners, and practitioners with a balanced work load were more likely to recommend crowns, as were practitioners who use optical scanners for digital impressions. Conclusions There is substantial variation in the likelihood of recommending a crown. While consensus exists in some areas (posterior endodontic treatment), variation dominates in others (size of an existing restoration). Recommendations varied by type of practice, network region, practice busyness, patient insurance status, and use of optical scanners. Practical Implications Recommendations for crowns may be influenced by factors unrelated to tooth and patient variables. A concern for tooth fracture -- whether from endodontic treatment, fractured teeth, or large restorations -- prompted many clinicians to recommend crowns. PMID:27492046

Latent Growth Classes of Alcohol-Related Blackouts over the First Two Years of College

PubMed Central

Merrill, Jennifer E.; Treloar, Hayley; Fernandez, Anne C.; Monnig, Mollie A.; Jackson, Kristina M.; Barnett, Nancy P.

2016-01-01

Alcohol-related blackouts are common among college student drinkers. The present study extends prior work by examining latent growth classes of blackouts and several predictors of class membership. Participants (N=709 college drinkers) completed a baseline survey at college entry and biweekly online assessments throughout freshman and sophomore years. Results revealed five latent growth class trajectories, reflecting varying experiences of blackouts at the beginning of college and differential change in blackouts over time. The largest class represented a relatively low risk group (LOW DECR; 47.3%) characterized by endorsement of no or very low likelihood of blackouts, and decreasing likelihood of blackouts over time. Another decreasing risk group (HIGH DECR; 11.1%) initially reported a high proportion of blackouts and had the steepest decrease in blackout risk over time. A small percentage showed consistently high likelihood of blackouts over time (HIGH STABLE; 4.1%). The remaining two groups were distinguished by relatively moderate (MOD STABLE; 14.9%) and lower (LOW STABLE; 22.6%) likelihood of blackouts, which remained stable over time. Comparisons between classes revealed that students with greater perceived peer drinking, perceived peer approval of drinking, and enhancement motives upon entry to college tended to be in higher-risk groups with consistent experiences of blackouts over time, whereas blackout likelihood decreased over time for students with greater conformity motives. Findings suggest that pre-college preventive interventions may be strengthened by considering not only factors related to current risk for blackouts and other alcohol-related consequences, but also those factors related to persistence of these behaviors over time. PMID:27736145

Dimensionality of the 9-item Utrecht Work Engagement Scale revisited: A Bayesian structural equation modeling approach.

PubMed

Fong, Ted C T; Ho, Rainbow T H

2015-01-01

The aim of this study was to reexamine the dimensionality of the widely used 9-item Utrecht Work Engagement Scale using the maximum likelihood (ML) approach and Bayesian structural equation modeling (BSEM) approach. Three measurement models (1-factor, 3-factor, and bi-factor models) were evaluated in two split samples of 1,112 health-care workers using confirmatory factor analysis and BSEM, which specified small-variance informative priors for cross-loadings and residual covariances. Model fit and comparisons were evaluated by posterior predictive p-value (PPP), deviance information criterion, and Bayesian information criterion (BIC). None of the three ML-based models showed an adequate fit to the data. The use of informative priors for cross-loadings did not improve the PPP for the models. The 1-factor BSEM model with approximately zero residual covariances displayed a good fit (PPP>0.10) to both samples and a substantially lower BIC than its 3-factor and bi-factor counterparts. The BSEM results demonstrate empirical support for the 1-factor model as a parsimonious and reasonable representation of work engagement.

A general methodology for maximum likelihood inference from band-recovery data

USGS Publications Warehouse

Conroy, M.J.; Williams, B.K.

1984-01-01

A numerical procedure is described for obtaining maximum likelihood estimates and associated maximum likelihood inference from band- recovery data. The method is used to illustrate previously developed one-age-class band-recovery models, and is extended to new models, including the analysis with a covariate for survival rates and variable-time-period recovery models. Extensions to R-age-class band- recovery, mark-recapture models, and twice-yearly marking are discussed. A FORTRAN program provides computations for these models.

The Role of Self-Efficacy for Bystander Helping Behaviors in Risky Alcohol Situations

PubMed Central

Krieger, Heather; Serrano, Surizaday; Neighbors, Clayton

2017-01-01

We examined the role of self-efficacy in preventing bystander inaction in dangerous alcohol situations. Participants (N = 504) completed an online survey that assessed whether they had previously witnessed or intervened in alcohol-related emergencies, their self-efficacy for intervening, and their likelihood of intervening in the future. Previously intervening was positively associated with self-efficacy and likelihood of intervening in the future. Furthermore, self-efficacy mediated the association between previously intervening and likelihood of intervening in the future. In conclusion, self-efficacy for intervening in social situations is associated with intervening in alcohol-related emergencies and is an important factor to consider when designing bystander interventions. PMID:29097835

The Role of Self-Efficacy for Bystander Helping Behaviors in Risky Alcohol Situations.

PubMed

Krieger, Heather; Serrano, Surizaday; Neighbors, Clayton

2017-04-01

We examined the role of self-efficacy in preventing bystander inaction in dangerous alcohol situations. Participants (N = 504) completed an online survey that assessed whether they had previously witnessed or intervened in alcohol-related emergencies, their self-efficacy for intervening, and their likelihood of intervening in the future. Previously intervening was positively associated with self-efficacy and likelihood of intervening in the future. Furthermore, self-efficacy mediated the association between previously intervening and likelihood of intervening in the future. In conclusion, self-efficacy for intervening in social situations is associated with intervening in alcohol-related emergencies and is an important factor to consider when designing bystander interventions.

The Factor Structure of the Spiritual Well-Being Scale in Veterans Experienced Chemical Weapon Exposure.

PubMed

Sharif Nia, Hamid; Pahlevan Sharif, Saeed; Boyle, Christopher; Yaghoobzadeh, Ameneh; Tahmasbi, Bahram; Rassool, G Hussein; Taebei, Mozhgan; Soleimani, Mohammad Ali

2018-04-01

This study aimed to determine the factor structure of the spiritual well-being among a sample of the Iranian veterans. In this methodological research, 211 male veterans of Iran-Iraq warfare completed the Paloutzian and Ellison spiritual well-being scale. Maximum likelihood (ML) with oblique rotation was used to assess domain structure of the spiritual well-being. The construct validity of the scale was assessed using confirmatory factor analysis (CFA), convergent validity, and discriminant validity. Reliability was evaluated with Cronbach's alpha, Theta (θ), and McDonald Omega (Ω) coefficients, intra-class correlation coefficient (ICC), and construct reliability (CR). Results of ML and CFA suggested three factors which were labeled "relationship with God," "belief in fate and destiny," and "life optimism." The ICC, coefficients of the internal consistency, and CR were >.7 for the factors of the scale. Convergent validity and discriminant validity did not fulfill the requirements. The Persian version of spiritual well-being scale demonstrated suitable validity and reliability among the veterans of Iran-Iraq warfare.

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

PubMed

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

2006-10-01

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

Maximum Likelihood Analysis in the PEN Experiment

NASA Astrophysics Data System (ADS)

Lehman, Martin

2013-10-01

The experimental determination of the π+ -->e+ ν (γ) decay branching ratio currently provides the most accurate test of lepton universality. The PEN experiment at PSI, Switzerland, aims to improve the present world average experimental precision of 3 . 3 ×10-3 to 5 ×10-4 using a stopped beam approach. During runs in 2008-10, PEN has acquired over 2 ×107 πe 2 events. The experiment includes active beam detectors (degrader, mini TPC, target), central MWPC tracking with plastic scintillator hodoscopes, and a spherical pure CsI electromagnetic shower calorimeter. The final branching ratio will be calculated using a maximum likelihood analysis. This analysis assigns each event a probability for 5 processes (π+ -->e+ ν , π+ -->μ+ ν , decay-in-flight, pile-up, and hadronic events) using Monte Carlo verified probability distribution functions of our observables (energies, times, etc). A progress report on the PEN maximum likelihood analysis will be presented. Work supported by NSF grant PHY-0970013.

Do-it-yourself statistics: A computer-assisted likelihood approach to analysis of data from genetic crosses.

PubMed Central

Robbins, L G

2000-01-01

Graduate school programs in genetics have become so full that courses in statistics have often been eliminated. In addition, typical introductory statistics courses for the "statistics user" rather than the nascent statistician are laden with methods for analysis of measured variables while genetic data are most often discrete numbers. These courses are often seen by students and genetics professors alike as largely irrelevant cookbook courses. The powerful methods of likelihood analysis, although commonly employed in human genetics, are much less often used in other areas of genetics, even though current computational tools make this approach readily accessible. This article introduces the MLIKELY.PAS computer program and the logic of do-it-yourself maximum-likelihood statistics. The program itself, course materials, and expanded discussions of some examples that are only summarized here are available at http://www.unisi. it/ricerca/dip/bio_evol/sitomlikely/mlikely.h tml. PMID:10628965

Prioritizing conservation investments for mammal species globally

PubMed Central

Wilson, Kerrie A.; Evans, Megan C.; Di Marco, Moreno; Green, David C.; Boitani, Luigi; Possingham, Hugh P.; Chiozza, Federica; Rondinini, Carlo

2011-01-01

We need to set priorities for conservation because we cannot do everything, everywhere, at the same time. We determined priority areas for investment in threat abatement actions, in both a cost-effective and spatially and temporally explicit way, for the threatened mammals of the world. Our analysis presents the first fine-resolution prioritization analysis for mammals at a global scale that accounts for the risk of habitat loss, the actions required to abate this risk, the costs of these actions and the likelihood of investment success. We evaluated the likelihood of success of investments using information on the past frequency and duration of legislative effectiveness at a country scale. The establishment of new protected areas was the action receiving the greatest investment, while restoration was never chosen. The resolution of the analysis and the incorporation of likelihood of success made little difference to this result, but affected the spatial location of these investments. PMID:21844046

Modeling Goal-Directed User Exploration in Human-Computer Interaction

DTIC Science & Technology

2011-02-01

scent, other factors including the layout position and grouping of options in the user-interface also affect user exploration and the likelihood of...grouping of options in the user-interface also affect user exploration and the likelihood of success. This dissertation contributes a new model of goal...better inform UI design. 1.1 RESEARCH GAPS IN MODELING In addition to infoscent, the layout of the UI also affects the choices made during

A meta-analysis of confocal laser endomicroscopy for the detection of neoplasia in patients with Barrett's esophagus.

PubMed

Xiong, Yi-Quan; Ma, Shu-Juan; Zhou, Jun-Hua; Zhong, Xue-Shan; Chen, Qing

2016-06-01

Barrett's esophagus (BE) is considered the most important risk factor for development of esophageal adenocarcinoma. Confocal laser endomicroscopy (CLE) is a recently developed technique used to diagnose neoplasia in BE. This meta-analysis was performed to assess the accuracy of CLE for diagnosis of neoplasia in BE. We searched EMBASE, PubMed, Cochrane Library, and Web of Science to identify relevant studies for all articles published up to June 27, 2015 in English. The quality of included studies was assessed using QUADAS-2. Per-patient and per-lesion pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with 95% confidence intervals (CIs) were calculated. In total, 14 studies were included in the final analysis, covering 789 patients with 4047 lesions. Seven studies were included in the per-patient analysis. Pooled sensitivity and specificity were 89% (95% CI: 0.82-0.94) and 83% (95% CI: 0.78-0.86), respectively. Ten studies were included in the per-lesion analysis. Compared with the PP analysis, the corresponding pooled sensitivity declined to 77% (95% CI: 0.73-0.81) and specificity increased to 89% (95% CI: 0.87-0.90). Subgroup analysis showed that probe-based CLE (pCLE) was superior to endoscope-based CLE (eCLE) in pooled specificity [91.4% (95% CI: 89.7-92.9) vs 86.1% (95% CI: 84.3-87.8)] and AUC for the sROC (0.885 vs 0.762). Confocal laser endomicroscopy is a valid method to accurately differentiate neoplasms from non-neoplasms in BE. It can be applied to BE surveillance and early diagnosis of esophageal adenocarcinoma. © 2015 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Further Evaluation of Covariate Analysis using Empirical Bayes Estimates in Population Pharmacokinetics: the Perception of Shrinkage and Likelihood Ratio Test.

PubMed

Xu, Xu Steven; Yuan, Min; Yang, Haitao; Feng, Yan; Xu, Jinfeng; Pinheiro, Jose

2017-01-01

Covariate analysis based on population pharmacokinetics (PPK) is used to identify clinically relevant factors. The likelihood ratio test (LRT) based on nonlinear mixed effect model fits is currently recommended for covariate identification, whereas individual empirical Bayesian estimates (EBEs) are considered unreliable due to the presence of shrinkage. The objectives of this research were to investigate the type I error for LRT and EBE approaches, to confirm the similarity of power between the LRT and EBE approaches from a previous report and to explore the influence of shrinkage on LRT and EBE inferences. Using an oral one-compartment PK model with a single covariate impacting on clearance, we conducted a wide range of simulations according to a two-way factorial design. The results revealed that the EBE-based regression not only provided almost identical power for detecting a covariate effect, but also controlled the false positive rate better than the LRT approach. Shrinkage of EBEs is likely not the root cause for decrease in power or inflated false positive rate although the size of the covariate effect tends to be underestimated at high shrinkage. In summary, contrary to the current recommendations, EBEs may be a better choice for statistical tests in PPK covariate analysis compared to LRT. We proposed a three-step covariate modeling approach for population PK analysis to utilize the advantages of EBEs while overcoming their shortcomings, which allows not only markedly reducing the run time for population PK analysis, but also providing more accurate covariate tests.

An analysis of crash likelihood : age versus driving experience

DOT National Transportation Integrated Search

1995-05-01

The study was designed to determine the crash likelihood of drivers in Michigan as a function of two independent variables: driver age and driving experience. The age variable had eight levels (18, 19, 20, 21, 22, 23, 24, and 25 years old) and the ex...

Pneumocystis pneumonia in HIV-positive patients in Spain: epidemiology and environmental risk factors

PubMed Central

Alvaro-Meca, Alejandro; Palomares-Sancho, Ines; Diaz, Asuncion; Resino, Rosa; De Miguel, Angel Gil; Resino, Salvador

2015-01-01

Introduction Specific environmental factors may play a role in the development of Pneumocystis pneumonia (PCP) in HIV-positive patients. The aim of this study was to estimate the PCP incidence and mortality in hospitalized HIV-positive patients in Spain during the combination antiretroviral therapy (cART) era (1997 to 2011), as well as to analyze the climatological factors and air pollution levels in relation to hospital admissions and deaths. Methods We carried out a retrospective study. Data were collected from the National Hospital Discharge Database and the State Meteorological Agency of Spain. A case-crossover analysis was applied to identify environmental risk factors related to hospitalizations and deaths. For each patient, climatic factors and pollution levels were assigned based on readings from the nearest meteorological station to his or her postal code. Results There were 13,139 new PCP diagnoses and 1754 deaths in hospitalized HIV-positive patients from 1997 to 2011. The PCP incidence (events per 1000 person-years) dropped from 11.6 in 1997 to 2000, to 5.4 in 2004 to 2011 (p<0.001). The mortality (events per 10,000 person-years) also decreased from 14.3 in 1997 to 2000, to 7.5 in 2004 to 2011 (p<0.001). Most hospital admissions and deaths occurred in the winter season and the fewest occurred in the summer, overlapping respectively with the lowest and highest temperatures of the year in Spain. Moreover, lower temperatures prior to PCP admission, as well as higher concentrations of NO2 and particulate matter up to 10 m in size (PM10) at the time of admission were associated with higher likelihoods of hospital admission due to PCP when two weeks, one month, 1.5 months or two months were used as controls (p<0.01). Furthermore, higher concentrations of ozone at one month (p=0.007), 1.5 months (p<0.001) and two months (p=0.006) prior to admission were associated with higher likelihoods of hospital admission with PCP. For PCP-related deaths, lower temperatures prior to admission and higher concentrations of atmospheric PM10 at the time of admission were related to higher likelihood of death when two weeks, one month and 1.5 months were used as controls (p<0.05). Conclusions PCP was a significant health problem in the cART era (1997 to 2011), and PCP epidemiology was adversely influenced by colder climatological factors and higher ambient air pollution levels. PMID:25997453

Is the Factor Observed in Investigations on the Item-Position Effect Actually the Difficulty Factor?

PubMed

Schweizer, Karl; Troche, Stefan

2018-02-01

In confirmatory factor analysis quite similar models of measurement serve the detection of the difficulty factor and the factor due to the item-position effect. The item-position effect refers to the increasing dependency among the responses to successively presented items of a test whereas the difficulty factor is ascribed to the wide range of item difficulties. The similarity of the models of measurement hampers the dissociation of these factors. Since the item-position effect should theoretically be independent of the item difficulties, the statistical ex post manipulation of the difficulties should enable the discrimination of the two types of factors. This method was investigated in two studies. In the first study, Advanced Progressive Matrices (APM) data of 300 participants were investigated. As expected, the factor thought to be due to the item-position effect was observed. In the second study, using data simulated to show the major characteristics of the APM data, the wide range of items with various difficulties was set to zero to reduce the likelihood of detecting the difficulty factor. Despite this reduction, however, the factor now identified as item-position factor, was observed in virtually all simulated datasets.

Nonparametric probability density estimation by optimization theoretic techniques

NASA Technical Reports Server (NTRS)

Scott, D. W.

1976-01-01

Two nonparametric probability density estimators are considered. The first is the kernel estimator. The problem of choosing the kernel scaling factor based solely on a random sample is addressed. An interactive mode is discussed and an algorithm proposed to choose the scaling factor automatically. The second nonparametric probability estimate uses penalty function techniques with the maximum likelihood criterion. A discrete maximum penalized likelihood estimator is proposed and is shown to be consistent in the mean square error. A numerical implementation technique for the discrete solution is discussed and examples displayed. An extensive simulation study compares the integrated mean square error of the discrete and kernel estimators. The robustness of the discrete estimator is demonstrated graphically.

Workplace Stress, Organizational Factors and EAP Utilization.

PubMed

Azzone, Vanessa; McCann, Bernard; Merrick, Elizabeth Levy; Hiatt, Deirdre; Hodgkin, Dominic; Horgan, Constance

2009-01-01

This study examined relationships between workplace stress, organizational factors and use of EAP counseling services delivered by network providers in a large, privately-insured population. Claims data were linked to measures of workplace stress, focus on wellness/prevention, EAP promotion, and EAP activities for health care plan enrollees from 26 employers. The association of external environment and work organization variables with use of EAP counseling services was examined. Higher levels of EAP promotion and worksite activities were associated with greater likelihood of service use. Greater focus on wellness/prevention and unusual and significant stress were associated with lower likelihood of service use. Results provide stakeholders with insights on approaches to increasing utilization of EAP services.

Workplace Stress, Organizational Factors and EAP Utilization

PubMed Central

Azzone, Vanessa; McCann, Bernard; Merrick, Elizabeth Levy; Hiatt, Deirdre; Hodgkin, Dominic; Horgan, Constance

2013-01-01

This study examined relationships between workplace stress, organizational factors and use of EAP counseling services delivered by network providers in a large, privately-insured population. Claims data were linked to measures of workplace stress, focus on wellness/prevention, EAP promotion, and EAP activities for health care plan enrollees from 26 employers. The association of external environment and work organization variables with use of EAP counseling services was examined. Higher levels of EAP promotion and worksite activities were associated with greater likelihood of service use. Greater focus on wellness/prevention and unusual and significant stress were associated with lower likelihood of service use. Results provide stakeholders with insights on approaches to increasing utilization of EAP services. PMID:24058322

Neural Networks Involved in Adolescent Reward Processing: An Activation Likelihood Estimation Meta-Analysis of Functional Neuroimaging Studies

PubMed Central

Silverman, Merav H.; Jedd, Kelly; Luciana, Monica

2015-01-01

Behavioral responses to, and the neural processing of, rewards change dramatically during adolescence and may contribute to observed increases in risk-taking during this developmental period. Functional MRI (fMRI) studies suggest differences between adolescents and adults in neural activation during reward processing, but findings are contradictory, and effects have been found in non-predicted directions. The current study uses an activation likelihood estimation (ALE) approach for quantitative meta-analysis of functional neuroimaging studies to: 1) confirm the network of brain regions involved in adolescents’ reward processing, 2) identify regions involved in specific stages (anticipation, outcome) and valence (positive, negative) of reward processing, and 3) identify differences in activation likelihood between adolescent and adult reward-related brain activation. Results reveal a subcortical network of brain regions involved in adolescent reward processing similar to that found in adults with major hubs including the ventral and dorsal striatum, insula, and posterior cingulate cortex (PCC). Contrast analyses find that adolescents exhibit greater likelihood of activation in the insula while processing anticipation relative to outcome and greater likelihood of activation in the putamen and amygdala during outcome relative to anticipation. While processing positive compared to negative valence, adolescents show increased likelihood for activation in the posterior cingulate cortex (PCC) and ventral striatum. Contrasting adolescent reward processing with the existing ALE of adult reward processing (Liu et al., 2011) reveals increased likelihood for activation in limbic, frontolimbic, and striatal regions in adolescents compared with adults. Unlike adolescents, adults also activate executive control regions of the frontal and parietal lobes. These findings support hypothesized elevations in motivated activity during adolescence. PMID:26254587

Examination of the Positive and Negative Syndrome Scale factor structure and longitudinal relationships with functioning in early psychosis.

PubMed

Best, Michael W; Grossman, Michael; Oyewumi, L Kola; Bowie, Christopher R

2016-04-01

We examined the factor structure of the Positive and Negative Syndrome Scale (PANSS) in early-episode psychosis and its relationships with functioning at baseline and follow-up. A total of 240 consecutive admissions to an early intervention in psychosis clinic were assessed at intake to the program with the PANSS, Global Assessment of Functioning (GAF) and Social and Occupational Functioning Assessment Scale (SOFAS). Seventy individuals were reassessed at follow-up. A maximum likelihood factor analysis was conducted on baseline PANSS scores and the ability of each factor to predict baseline and follow-up GAF and SOFAS was examined. A five-factor model with varimax rotation was the best fit to our data and was largely congruent with factors found previously. The negative symptom factor was the best predictor of GAF and SOFAS at baseline and follow-up. Negative symptoms are the best symptomatic predictor of functioning in individuals with early psychosis and are an important treatment target to improve recovery. © 2014 Wiley Publishing Asia Pty Ltd.

HUMAN PROSTATE CANCER RISK FACTORS

EPA Science Inventory

Prostate cancer has the highest prevalence of any non-skin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating an...

Defining physicians' readiness to screen and manage intimate partner violence in Greek primary care settings.

PubMed

Papadakaki, Maria; Prokopiadou, Dimitra; Petridou, Eleni; Kogevinas, Manolis; Lionis, Christos

2012-06-01

The current article aims to translate the PREMIS (Physician Readiness to Manage Intimate Partner Violence) survey into the Greek language and test its validity and reliability in a sample of primary care physicians. The validation study was conducted in 2010 and involved all the general practitioners serving two adjacent prefectures of Greece (n = 80). Maximum-likelihood factor analysis (MLF) was used to extract key survey factors. The instrument was further assessed for the following psychometric properties: (a) scale reliability, (b) item-specific reliability, (c) test-retest reliability, (d) scale construct validity, and (e) internal predictive validity. The MLF analysis of 23 opinion items revealed a seven-factor solution (preparation, constraint, workplace issues, screening, self-efficacy, alcohol/drugs, victim understanding), which was statistically sound (p = .293). Most of the newly derived scales displayed satisfactory internal consistency (α ≥ .60), high item-specific reliability, strong construct, and internal predictive validity (F = 2.82; p = .004), and high repeatability when retested with 20 individuals (intraclass correlation coefficient [ICC] > .70). The tool was found appropriate to facilitate the identification of competence deficits and the evaluation of training initiatives.

On Muthen's Maximum Likelihood for Two-Level Covariance Structure Models

ERIC Educational Resources Information Center

Yuan, Ke-Hai; Hayashi, Kentaro

2005-01-01

Data in social and behavioral sciences are often hierarchically organized. Special statistical procedures that take into account the dependence of such observations have been developed. Among procedures for 2-level covariance structure analysis, Muthen's maximum likelihood (MUML) has the advantage of easier computation and faster convergence. When…

Mixture Rasch Models with Joint Maximum Likelihood Estimation

ERIC Educational Resources Information Center

Willse, John T.

2011-01-01

This research provides a demonstration of the utility of mixture Rasch models. Specifically, a model capable of estimating a mixture partial credit model using joint maximum likelihood is presented. Like the partial credit model, the mixture partial credit model has the beneficial feature of being appropriate for analysis of assessment data…

Maximum likelihood solution for inclination-only data in paleomagnetism

NASA Astrophysics Data System (ADS)

Arason, P.; Levi, S.

2010-08-01

We have developed a new robust maximum likelihood method for estimating the unbiased mean inclination from inclination-only data. In paleomagnetic analysis, the arithmetic mean of inclination-only data is known to introduce a shallowing bias. Several methods have been introduced to estimate the unbiased mean inclination of inclination-only data together with measures of the dispersion. Some inclination-only methods were designed to maximize the likelihood function of the marginal Fisher distribution. However, the exact analytical form of the maximum likelihood function is fairly complicated, and all the methods require various assumptions and approximations that are often inappropriate. For some steep and dispersed data sets, these methods provide estimates that are significantly displaced from the peak of the likelihood function to systematically shallower inclination. The problem locating the maximum of the likelihood function is partly due to difficulties in accurately evaluating the function for all values of interest, because some elements of the likelihood function increase exponentially as precision parameters increase, leading to numerical instabilities. In this study, we succeeded in analytically cancelling exponential elements from the log-likelihood function, and we are now able to calculate its value anywhere in the parameter space and for any inclination-only data set. Furthermore, we can now calculate the partial derivatives of the log-likelihood function with desired accuracy, and locate the maximum likelihood without the assumptions required by previous methods. To assess the reliability and accuracy of our method, we generated large numbers of random Fisher-distributed data sets, for which we calculated mean inclinations and precision parameters. The comparisons show that our new robust Arason-Levi maximum likelihood method is the most reliable, and the mean inclination estimates are the least biased towards shallow values.

Anticipating cognitive effort: roles of perceived error-likelihood and time demands.

PubMed

Dunn, Timothy L; Inzlicht, Michael; Risko, Evan F

2017-11-13

Why are some actions evaluated as effortful? In the present set of experiments we address this question by examining individuals' perception of effort when faced with a trade-off between two putative cognitive costs: how much time a task takes vs. how error-prone it is. Specifically, we were interested in whether individuals anticipate engaging in a small amount of hard work (i.e., low time requirement, but high error-likelihood) vs. a large amount of easy work (i.e., high time requirement, but low error-likelihood) as being more effortful. In between-subject designs, Experiments 1 through 3 demonstrated that individuals anticipate options that are high in perceived error-likelihood (yet less time consuming) as more effortful than options that are perceived to be more time consuming (yet low in error-likelihood). Further, when asked to evaluate which of the two tasks was (a) more effortful, (b) more error-prone, and (c) more time consuming, effort-based and error-based choices closely tracked one another, but this was not the case for time-based choices. Utilizing a within-subject design, Experiment 4 demonstrated overall similar pattern of judgments as Experiments 1 through 3. However, both judgments of error-likelihood and time demand similarly predicted effort judgments. Results are discussed within the context of extant accounts of cognitive control, with considerations of how error-likelihood and time demands may independently and conjunctively factor into judgments of cognitive effort.

Validation of a heteroscedastic hazards regression model.

PubMed

Wu, Hong-Dar Isaac; Hsieh, Fushing; Chen, Chen-Hsin

2002-03-01

A Cox-type regression model accommodating heteroscedasticity, with a power factor of the baseline cumulative hazard, is investigated for analyzing data with crossing hazards behavior. Since the approach of partial likelihood cannot eliminate the baseline hazard, an overidentified estimating equation (OEE) approach is introduced in the estimation procedure. It by-product, a model checking statistic, is presented to test for the overall adequacy of the heteroscedastic model. Further, under the heteroscedastic model setting, we propose two statistics to test the proportional hazards assumption. Implementation of this model is illustrated in a data analysis of a cancer clinical trial.

Prevalence of consistent condom use with various types of sex partners and associated factors among money boys in Changsha, China.

PubMed

Wang, Lian-Hong; Yan, Jin; Yang, Guo-Li; Long, Shuo; Yu, Yong; Wu, Xi-Lin

2015-04-01

Money boys with inconsistent condom use (less than 100% of the time) are at high risk of infection by human immunodeficiency virus (HIV) or sexually transmitted infection (STI), but relatively little research has examined their risk behaviors. We investigated the prevalence of consistent condom use (100% of the time) and associated factors among money boys. A cross-sectional study using a structured questionnaire was conducted among money boys in Changsha, China, between July 2012 and January 2013. Independent variables included socio-demographic data, substance abuse history, work characteristics, and self-reported HIV and STI history. Dependent variables included the consistent condom use with different types of sex partners. Among the participants, 82.4% used condoms consistently with male clients, 80.2% with male sex partners, and 77.1% with female sex partners in the past 3 months. A multiple stepwise logistic regression model identified four statistically significant factors associated with lower likelihoods of consistent condom use with male clients: age group, substance abuse, lack of an "employment" arrangement, and having no HIV test within the prior 6 months. In a similar model, only one factor associated significantly with lower likelihoods of consistent condom use with male sex partners was identified in multiple stepwise logistic regression analyses: having no HIV test within the prior six months. As for female sex partners, two significant variables were statistically significant in the multiple stepwise logistic regression analysis: having no HIV test within the prior 6 months and having STI history. Interventions which are linked with more realistic and acceptable HIV prevention methods are greatly warranted and should increase risk awareness and the behavior of consistent condom use in both commercial and personal relationship. © 2015 International Society for Sexual Medicine.

Development of probabilistic emission inventories of air toxics for Jacksonville, Florida, USA.

PubMed

Zhao, Yuchao; Frey, H Christopher

2004-11-01

Probabilistic emission inventories were developed for 1,3-butadiene, mercury (Hg), arsenic (As), benzene, formaldehyde, and lead for Jacksonville, FL. To quantify inter-unit variability in empirical emission factor data, the Maximum Likelihood Estimation (MLE) method or the Method of Matching Moments was used to fit parametric distributions. For data sets that contain nondetected measurements, a method based upon MLE was used for parameter estimation. To quantify the uncertainty in urban air toxic emission factors, parametric bootstrap simulation and empirical bootstrap simulation were applied to uncensored and censored data, respectively. The probabilistic emission inventories were developed based on the product of the uncertainties in the emission factors and in the activity factors. The uncertainties in the urban air toxics emission inventories range from as small as -25 to +30% for Hg to as large as -83 to +243% for As. The key sources of uncertainty in the emission inventory for each toxic are identified based upon sensitivity analysis. Typically, uncertainty in the inventory of a given pollutant can be attributed primarily to a small number of source categories. Priorities for improving the inventories and for refining the probabilistic analysis are discussed.

Adolescent smoking and family structure in Europe.

PubMed

Griesbach, Dawn; Amos, Amanda; Currie, Candace

2003-01-01

This paper examines the relationship between family structure and smoking among 15-year-old adolescents in seven European countries. It also investigates the association between family structure and a number of known smoking risk factors including family socio-economic status, the adolescent's disposable income, parental smoking and the presence of other smokers in the adolescent's home. Findings are based on 1998 survey data from a cross-national study of health behaviours among children and adolescents. Family structure was found to be significantly associated with smoking among 15-year-olds in all countries, with smoking prevalence lowest among adolescents in intact families and highest among adolescents in stepfamilies. Multivariate analysis showed that several risk factors were associated with higher smoking prevalences in all countries, but that even after these other factors were taken into account, there was an increased likelihood of smoking among adolescents in stepfamilies. Further research is needed to determine the possible reasons for this association.

Betel nut usage is a major risk factor for coronary artery disease.

PubMed

Khan, Muhammad Shahzeb; Bawany, Faizan Imran; Ahmed, Muhammad Umer; Hussain, Mehwish; Khan, Asadullah; Lashari, Muhammad Nawaz

2013-12-27

The objective of our study was to assess betel nut usage as one of the major risk factors associated with coronary artery disease. This case control study consisted of 300 controls and 300 cases. A structured questionnaire was administered to the participants to assess consumption of betel nut and confounding variables. A respondent was considered a regular consumer of betel nut if he/she consumed one or more pieces of betel nut every day for a period of greater than 6 months. About 8 in 10 betel nut chewers developed coronary artery disease. After adjusting for diabetes and hypertension, the odds ratio analysis depicted 7.72 times greater likelihood for coronary artery disease in patients who chewed betel nut for more than 10 years. Our study concludes that betel nut chewing is a significant risk factor leading to the development of coronary artery disease.

Betel Nut Usage Is a Major Risk Factor for Coronary Artery Disease

PubMed Central

Khan, Muhammad Shahzeb; Bawany, Faizan Imran; Ahmed, Muhammad Umer; Hussain, Mehwish; Khan, Asadullah; Lashari, Muhammad Nawaz

2014-01-01

Aim: The objective of our study was to assess betel nut usage as one of the major risk factors associated with coronary artery disease. Methods: This case control study consisted of 300 controls and 300 cases. A structured questionnaire was administered to the participants to assess consumption of betel nut and confounding variables. A respondent was considered a regular consumer of betel nut if he/she consumed one or more pieces of betel nut every day for a period of greater than 6 months. Results: About 8 in 10 betel nut chewers developed coronary artery disease. After adjusting for diabetes and hypertension, the odds ratio analysis depicted 7.72 times greater likelihood for coronary artery disease in patients who chewed betel nut for more than 10 years. Conclusion: Our study concludes that betel nut chewing is a significant risk factor leading to the development of coronary artery disease. PMID:24576380

A Primer on Risks, Issues and Opportunities

DTIC Science & Technology

2016-08-01

likelihood or consequence. A risk has three main parts: a future root cause, a likelihood and a consequence. The future root cause is determined...through root cause analysis, which is the most important part of any risk management effort. SPECIAL SECTION: RISK MANAGEMENT Defense AT&L: July-August...2016 10 Root cause analysis gets to the heart of the risk. Why does the risk exist? What is its nature? How will the risk occur? What should be

Stochastic capture zone analysis of an arsenic-contaminated well using the generalized likelihood uncertainty estimator (GLUE) methodology

NASA Astrophysics Data System (ADS)

Morse, Brad S.; Pohll, Greg; Huntington, Justin; Rodriguez Castillo, Ramiro

2003-06-01

In 1992, Mexican researchers discovered concentrations of arsenic in excess of World Heath Organization (WHO) standards in several municipal wells in the Zimapan Valley of Mexico. This study describes a method to delineate a capture zone for one of the most highly contaminated wells to aid in future well siting. A stochastic approach was used to model the capture zone because of the high level of uncertainty in several input parameters. Two stochastic techniques were performed and compared: "standard" Monte Carlo analysis and the generalized likelihood uncertainty estimator (GLUE) methodology. The GLUE procedure differs from standard Monte Carlo analysis in that it incorporates a goodness of fit (termed a likelihood measure) in evaluating the model. This allows for more information (in this case, head data) to be used in the uncertainty analysis, resulting in smaller prediction uncertainty. Two likelihood measures are tested in this study to determine which are in better agreement with the observed heads. While the standard Monte Carlo approach does not aid in parameter estimation, the GLUE methodology indicates best fit models when hydraulic conductivity is approximately 10-6.5 m/s, with vertically isotropic conditions and large quantities of interbasin flow entering the basin. Probabilistic isochrones (capture zone boundaries) are then presented, and as predicted, the GLUE-derived capture zones are significantly smaller in area than those from the standard Monte Carlo approach.

Testing Measurement Invariance Using MIMIC: Likelihood Ratio Test with a Critical Value Adjustment

ERIC Educational Resources Information Center

Kim, Eun Sook; Yoon, Myeongsun; Lee, Taehun

2012-01-01

Multiple-indicators multiple-causes (MIMIC) modeling is often used to test a latent group mean difference while assuming the equivalence of factor loadings and intercepts over groups. However, this study demonstrated that MIMIC was insensitive to the presence of factor loading noninvariance, which implies that factor loading invariance should be…

Comparisons of Four Methods for Estimating a Dynamic Factor Model

ERIC Educational Resources Information Center

Zhang, Zhiyong; Hamaker, Ellen L.; Nesselroade, John R.

2008-01-01

Four methods for estimating a dynamic factor model, the direct autoregressive factor score (DAFS) model, are evaluated and compared. The first method estimates the DAFS model using a Kalman filter algorithm based on its state space model representation. The second one employs the maximum likelihood estimation method based on the construction of a…

Using Fuzzy Multiple Criteria Decision-Making Approach for Assessing the Risk of Railway Reconstruction Project in Taiwan

PubMed Central

Yu, Shih-Heng; Chang, Dong-Shang

2014-01-01

This study investigates the risk factors in railway reconstruction project through complete literature reviews on construction project risks and scrutinizing experiences and challenges of railway reconstructions in Taiwan. Based on the identified risk factors, an assessing framework based on the fuzzy multicriteria decision-making (fuzzy MCDM) approach to help construction agencies build awareness of the critical risk factors on the execution of railway reconstruction project, measure the impact and occurrence likelihood for these risk factors. Subjectivity, uncertainty and vagueness within the assessment process are dealt with using linguistic variables parameterized by trapezoid fuzzy numbers. By multiplying the degree of impact and the occurrence likelihood of risk factors, estimated severity values of each identified risk factor are determined. Based on the assessment results, the construction agencies were informed of what risks should be noticed and what they should do to avoid the risks. That is, it enables construction agencies of railway reconstruction to plan the appropriate risk responses/strategies to increase the opportunity of project success and effectiveness. PMID:24772014

Changes in food habits after migration among South Asians settled in Oslo: the effect of demographic, socio-economic and integration factors.

PubMed

Wandel, Margareta; Råberg, Marte; Kumar, Bernadette; Holmboe-Ottesen, Gerd

2008-01-01

The aim is to explore changes in food habits after migration, and the resultant present food consumption patterns, as well as the effect of demographic, socio-economic and integration factors on these changes. Analyses were based on data collected through the Oslo Immigrant Health study, from 629 persons 30-60 years of age, born in Sri Lanka and Pakistan, and living in Oslo, Norway. A majority of the Sri Lankans reported increase in the consumption of meat, milk, butter, margarine and potatoes. Around half of those from Pakistan reported increased consumption of oil, meat, fish and potatoes. Both groups reported a decrease in bean and lentil consumption. Multivariate regression showed that age was negatively related to increases in butter and margarine consumption, and a good command of the Norwegian language reduced the likelihood of increased consumption of oil and butter. The likelihood of having present fat and sugar rich food patterns were reduced with age and years of education, whereas scoring high on an index of integration increased the likelihood of a fat rich food pattern. In conclusion, a number of demographic and socio-cultural factors may modify the changes in food habits after migration. Some of these may have substantial health implications.

48 CFR 1352.215-75 - Evaluation criteria.

Code of Federal Regulations, 2011 CFR

2011-10-01

... relative importance among the technical evaluation factors.] Based upon the results of the integrated... as the offeror's planned management of consultants and subcontractors, if applicable. Factor 2... likelihood that that offeror can successfully perform the contract requirements and the degree of the risk of...

Investigation on occupant injury severity in rear-end crashes involving trucks as the front vehicle in Beijing area, China.

PubMed

Yuan, Quan; Lu, Meng; Theofilatos, Athanasios; Li, Yi-Bing

2017-02-01

Rear-end crashes attribute to a large portion of total crashes in China, which lead to many casualties and property damage, especially when involving commercial vehicles. This paper aims to investigate the critical factors for occupant injury severity in the specific rear-end crash type involving trucks as the front vehicle (FV). This paper investigated crashes occurred from 2011 to 2013 in Beijing area, China and selected 100 qualified cases i.e., rear-end crashes involving trucks as the FV. The crash data were supplemented with interviews from police officers and vehicle inspection. A binary logistic regression model was used to build the relationship between occupant injury severity and corresponding affecting factors. Moreover, a multinomial logistic model was used to predict the likelihood of fatal or severe injury or no injury in a rear-end crash. The results provided insights on the characteristics of driver, vehicle and environment, and the corresponding influences on the likelihood of a rear-end crash. The binary logistic model showed that drivers' age, weight difference between vehicles, visibility condition and lane number of road significantly increased the likelihood for severe injury of rear-end crash. The multinomial logistic model and the average direct pseudo-elasticity of variables showed that night time, weekdays, drivers from other provinces and passenger vehicles as rear vehicles significantly increased the likelihood of rear drivers being fatal. All the abovementioned significant factors should be improved, such as the conditions of lighting and the layout of lanes on roads. Two of the most common driver factors are drivers' age and drivers' original residence. Young drivers and outsiders have a higher injury severity. Therefore it is imperative to enhance the safety education and management on the young drivers who steer heavy duty truck from other cities to Beijing on weekdays. Copyright © 2016 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Extrinsic and Intrinsic Help-Seeking Motivation in the Assessment of Cognitive Decline.

PubMed

Haussmann, Robert; Mayer-Pelinski, René; Borchardt, Maike; Beier, Fabrice; Helling, Franziska; Buthut, Maria; Meissner, Gisa; Lange, Jan; Zweiniger, Anne; Donix, Markus

2018-06-01

Diagnostic assessments for dementia include the evaluation of subjective memory impairment, dementia worries, or depressive symptoms. Data on the predictive value of these factors remain unclear, and varying help-seeking behavior may contribute to this finding. We investigate whether differentiating help-seeking motivation from other psychological factors associated with cognitive impairment would enhance the prediction of diagnostic outcomes in a memory clinic. We obtained information on help-seeking motivation from 171 patients who underwent routine diagnostic assessments. Utilizing a discriminant correspondence analysis, our results indicate that extrinsic motivation increases the likelihood of receiving a dementia diagnosis, whereas depression or the duration of deficits carries discriminatory information to further guide the differentiation of prodromal dementia. Recognizing motivational aspects of help-seeking behavior can complement the clinical evaluation of cognitive performance.

Explanation of obsessive-compulsive disorder and major depressive disorder on the basis of thought-action fusion.

PubMed

Ghamari Kivi, Hossein; Mohammadipour Rik, Ne'mat; Sadeghi Movahhed, Fariba

2013-01-01

Thought-action fusion (TAF) refers to the tendency to assume incorrect causal relationship between one's own thoughts and external reality, in which, thoughts and actions are treated as equivalents. This construct is present to development and maintenance of many psychological disorders. The aim of the present study was to predict obsessive-compulsive disorder (OCD) and its types, and major depressive disorder (MDD) with TAF and its levels. Two groups, included 50 persons with OCD and MDD, respectively, were selected by convenience sampling method in private and governmental psychiatric centers in Ardabil, Iran. Then, they responded to Beck Depression Inventory, Padua Inventory and TAF scale. Data were analysed using multiple regressions analysis by stepwise method. TAF or its subtypes (moral TAF, likelihood-self TAF and likelihood-others TAF) can explain 14% of MDD variance (p < 0.01), 15% of OCD variance (p < 0.01), and 8-21% of OCD types variance (p < 0.05). Moral TAF had high levels in OCD and MDD. The construct of TAF is not specific factor for OCD, and it is present in MDD, too. None.

Diagnostic reasoning strategies and diagnostic success.

PubMed

Coderre, S; Mandin, H; Harasym, P H; Fick, G H

2003-08-01

Cognitive psychology research supports the notion that experts use mental frameworks or "schemes", both to organize knowledge in memory and to solve clinical problems. The central purpose of this study was to determine the relationship between problem-solving strategies and the likelihood of diagnostic success. Think-aloud protocols were collected to determine the diagnostic reasoning used by experts and non-experts when attempting to diagnose clinical presentations in gastroenterology. Using logistic regression analysis, the study found that there is a relationship between diagnostic reasoning strategy and the likelihood of diagnostic success. Compared to hypothetico-deductive reasoning, the odds of diagnostic success were significantly greater when subjects used the diagnostic strategies of pattern recognition and scheme-inductive reasoning. Two other factors emerged as independent determinants of diagnostic success: expertise and clinical presentation. Not surprisingly, experts outperformed novices, while the content area of the clinical cases in each of the four clinical presentations demonstrated varying degrees of difficulty and thus diagnostic success. These findings have significant implications for medical educators. It supports the introduction of "schemes" as a means of enhancing memory organization and improving diagnostic success.

EVALUATION OF A NEW MEAN SCALED AND MOMENT ADJUSTED TEST STATISTIC FOR SEM.

PubMed

Tong, Xiaoxiao; Bentler, Peter M

2013-01-01

Recently a new mean scaled and skewness adjusted test statistic was developed for evaluating structural equation models in small samples and with potentially nonnormal data, but this statistic has received only limited evaluation. The performance of this statistic is compared to normal theory maximum likelihood and two well-known robust test statistics. A modification to the Satorra-Bentler scaled statistic is developed for the condition that sample size is smaller than degrees of freedom. The behavior of the four test statistics is evaluated with a Monte Carlo confirmatory factor analysis study that varies seven sample sizes and three distributional conditions obtained using Headrick's fifth-order transformation to nonnormality. The new statistic performs badly in most conditions except under the normal distribution. The goodness-of-fit χ(2) test based on maximum-likelihood estimation performed well under normal distributions as well as under a condition of asymptotic robustness. The Satorra-Bentler scaled test statistic performed best overall, while the mean scaled and variance adjusted test statistic outperformed the others at small and moderate sample sizes under certain distributional conditions.

Functional form and risk adjustment of hospital costs: Bayesian analysis of a Box-Cox random coefficients model.

PubMed

Hollenbeak, Christopher S

2005-10-15

While risk-adjusted outcomes are often used to compare the performance of hospitals and physicians, the most appropriate functional form for the risk adjustment process is not always obvious for continuous outcomes such as costs. Semi-log models are used most often to correct skewness in cost data, but there has been limited research to determine whether the log transformation is sufficient or whether another transformation is more appropriate. This study explores the most appropriate functional form for risk-adjusting the cost of coronary artery bypass graft (CABG) surgery. Data included patients undergoing CABG surgery at four hospitals in the midwest and were fit to a Box-Cox model with random coefficients (BCRC) using Markov chain Monte Carlo methods. Marginal likelihoods and Bayes factors were computed to perform model comparison of alternative model specifications. Rankings of hospital performance were created from the simulation output and the rankings produced by Bayesian estimates were compared to rankings produced by standard models fit using classical methods. Results suggest that, for these data, the most appropriate functional form is not logarithmic, but corresponds to a Box-Cox transformation of -1. Furthermore, Bayes factors overwhelmingly rejected the natural log transformation. However, the hospital ranking induced by the BCRC model was not different from the ranking produced by maximum likelihood estimates of either the linear or semi-log model. Copyright (c) 2005 John Wiley & Sons, Ltd.

Inter- and independent effects of region and race/ethnicity on variety of fruit and vegetable consumption in the USA: 2011 Behavioral Risk Factor Surveillance System (BRFSS).

PubMed

Tichenor, Nicole; Conrad, Zach

2016-01-01

(i) To estimate the independent and combined effects of race/ethnicity and region on the variety of fruits and vegetables consumed in the USA in 2011; and (ii) to assess whether and to what extent race/ethnicity and region may synergistically influence variety of fruit and vegetable consumption. Cross-sectional analysis. Multivariate logistic regression predicted the likelihood of meeting fruit and vegetable variety indicators independently and in combination for each race/ethnicity and region. Interaction effects models were used to test for interaction effects between race/ethnicity and region on fruit and vegetable variety. The 2011 Behavioral Risk Factor Surveillance System (BRFSS). The sample consisted of 275 864 adult respondents. Fewer than half of respondents consumed fruit and all vegetable subcategories at least once weekly. The adjusted likelihood of meeting fruit and vegetable variety indicators varied significantly by race/ethnicity and region (P<0·05). Significant interactions between race/ethnicity and region were found for at least once weekly consumption of beans, orange vegetables, all vegetables, and fruit and all vegetables (P<0·05). Our results reinforce previous findings that the variety of vegetable consumption is lacking and is particularly evident among some population subgroups, such as non-Hispanic blacks in the Midwest USA, who may benefit from targeted dietary interventions.

Understanding of prognosis among parents of children with cancer: parental optimism and the parent-physician interaction.

PubMed

Mack, Jennifer W; Cook, E Francis; Wolfe, Joanne; Grier, Holcombe E; Cleary, Paul D; Weeks, Jane C

2007-04-10

Patients often overestimate their chances of surviving cancer. Factors that contribute to accurate understanding of prognosis are not known. We assessed understanding of likelihood of cure and functional outcome among parents of children with cancer and sought to identify factors that place parents at risk for overly optimistic beliefs about prognosis. We conducted a cross-sectional survey of 194 parents of children with cancer (response rate, 70%) who were treated at the Dana-Farber Cancer Institute and Children's Hospital in Boston, MA, and the children's physicians. Parent and physician expectations for likelihood of cure and functional outcome were compared. In 152 accurate or optimistic parents, we determined factors associated with accurate understanding of likelihood of cure compared with optimism. The majority of parents (61%) were more optimistic than physicians about the likelihood of cure. Parents' beliefs about other outcomes of cancer treatment were similar (quality-of-life impairment, P = .70) or more pessimistic (physical impairment, P = .01; intellectual impairment, P = .01) than physicians' beliefs. Parents and physicians were more likely to agree about chances of cure when physicians had confidence in knowledge of prognosis (odds ratio [OR] = 2.55, P = .004) and allowed parents to take their preferred decision-making role (OR = 1.89, P = .019). Parents of children with cancer are overly optimistic about chances of cure but not about other outcomes of cancer therapy. Parents tend to be overly optimistic about cure when physicians have little confidence and when the decision-making process does not meet parents' preferences. These findings suggest that physicians are partly responsible for parents' unrealistic expectations about cure.

Pre-test probability of obstructive coronary stenosis in patients undergoing coronary CT angiography: Comparative performance of the modified diamond-Forrester algorithm versus methods incorporating cardiovascular risk factors.

PubMed

Ferreira, António Miguel; Marques, Hugo; Tralhão, António; Santos, Miguel Borges; Santos, Ana Rita; Cardoso, Gonçalo; Dores, Hélder; Carvalho, Maria Salomé; Madeira, Sérgio; Machado, Francisco Pereira; Cardim, Nuno; de Araújo Gonçalves, Pedro

2016-11-01

Current guidelines recommend the use of the Modified Diamond-Forrester (MDF) method to assess the pre-test likelihood of obstructive coronary artery disease (CAD). We aimed to compare the performance of the MDF method with two contemporary algorithms derived from multicenter trials that additionally incorporate cardiovascular risk factors: the calculator-based 'CAD Consortium 2' method, and the integer-based CONFIRM score. We assessed 1069 consecutive patients without known CAD undergoing coronary CT angiography (CCTA) for stable chest pain. Obstructive CAD was defined as the presence of coronary stenosis ≥50% on 64-slice dual-source CT. The three methods were assessed for calibration, discrimination, net reclassification, and changes in proposed downstream testing based upon calculated pre-test likelihoods. The observed prevalence of obstructive CAD was 13.8% (n=147). Overestimations of the likelihood of obstructive CAD were 140.1%, 9.8%, and 18.8%, respectively, for the MDF, CAD Consortium 2 and CONFIRM methods. The CAD Consortium 2 showed greater discriminative power than the MDF method, with a C-statistic of 0.73 vs. 0.70 (p<0.001), while the CONFIRM score did not (C-statistic 0.71, p=0.492). Reclassification of pre-test likelihood using the 'CAD Consortium 2' or CONFIRM scores resulted in a net reclassification improvement of 0.19 and 0.18, respectively, which would change the diagnostic strategy in approximately half of the patients. Newer risk factor-encompassing models allow for a more precise estimation of pre-test probabilities of obstructive CAD than the guideline-recommended MDF method. Adoption of these scores may improve disease prediction and change the diagnostic pathway in a significant proportion of patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Factors Associated With High-Risk Alcohol Consumption Among LGB Older Adults: The Roles of Gender, Social Support, Perceived Stress, Discrimination, and Stigma.

PubMed

Bryan, Amanda E B; Kim, Hyun-Jun; Fredriksen-Goldsen, Karen I

2017-02-01

Lesbian, gay, and bisexual (LGB) adults have elevated rates of high-risk alcohol consumption compared with heterosexual adults. Although drinking tends to decline with age in the general population, we know little about LGB older adults' drinking. Using 2014 data from Aging with Pride: National Health, Aging, and Sexuality/Gender Study (NHAS), we aimed to identify factors associated with high-risk drinking in LGB older adults. A U.S. sample of 2,351 LGB adults aged 50-98 years completed a survey about personal and social experiences, substance use, and health. Multinomial logistic regression was conducted to identify predictors of past-month high-risk alcohol consumption. Approximately one fifth (20.6%) of LGB older adults reported high-risk drinking, with nonsignificantly different rates between men (22.4%) and women (18.4%). For women, current smoking and greater social support were associated with greater likelihood of high-risk drinking; older age, higher income, recovery from addiction, and greater perceived stress were associated with lower likelihood. For men, higher income, current smoking, and greater day-to-day discrimination were associated with greater likelihood of high-risk drinking; transgender identity and recovery from addiction were associated with lower likelihood. Social contexts and perceived drinking norms may encourage higher levels of alcohol consumption in LGB older women, whereas men's drinking may be linked with discrimination-related stress. Prevention and intervention with this population should take into account gender differences and sexual minority-specific risk factors. With future waves of data, we will be able to examine LGB older adults' drinking trajectories over time. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Accounting for measurement error in biomarker data and misclassification of subtypes in the analysis of tumor data

PubMed Central

Nevo, Daniel; Zucker, David M.; Tamimi, Rulla M.; Wang, Molin

2017-01-01

A common paradigm in dealing with heterogeneity across tumors in cancer analysis is to cluster the tumors into subtypes using marker data on the tumor, and then to analyze each of the clusters separately. A more specific target is to investigate the association between risk factors and specific subtypes and to use the results for personalized preventive treatment. This task is usually carried out in two steps–clustering and risk factor assessment. However, two sources of measurement error arise in these problems. The first is the measurement error in the biomarker values. The second is the misclassification error when assigning observations to clusters. We consider the case with a specified set of relevant markers and propose a unified single-likelihood approach for normally distributed biomarkers. As an alternative, we consider a two-step procedure with the tumor type misclassification error taken into account in the second-step risk factor analysis. We describe our method for binary data and also for survival analysis data using a modified version of the Cox model. We present asymptotic theory for the proposed estimators. Simulation results indicate that our methods significantly lower the bias with a small price being paid in terms of variance. We present an analysis of breast cancer data from the Nurses’ Health Study to demonstrate the utility of our method. PMID:27558651

Factors related to clinical pregnancy after vitrified-warmed embryo transfer: a retrospective and multivariate logistic regression analysis of 2313 transfer cycles.

PubMed

Shi, Wenhao; Zhang, Silin; Zhao, Wanqiu; Xia, Xue; Wang, Min; Wang, Hui; Bai, Haiyan; Shi, Juanzi

2013-07-01

What factors does multivariate logistic regression show to be significantly associated with the likelihood of clinical pregnancy in vitrified-warmed embryo transfer (VET) cycles? Assisted hatching (AH) and if the reason to freeze embryos was to avoid the risk of ovarian hyperstimulation syndrome (OHSS) were significantly positively associated with a greater likelihood of clinical pregnancy. Single factor analysis has shown AH, number of embryos transferred and the reason of freezing for OHSS to be positively and damaged blastomere to be negatively significantly associated with the chance of clinical pregnancy after VET. It remains unclear what factors would be significant after multivariate analysis. The study was a retrospective analysis of 2313 VET cycles from 1481 patients performed between January 2008 and April 2012. A multivariate logistic regression analysis was performed to identify the factors to affect clinical pregnancy outcome of VET. There were 22 candidate variables selected based on clinical experiences and the literature. With the thresholds of α entry = α removal= 0.05 for both variable entry and variable removal, eight variables were chosen to contribute the multivariable model by the bootstrap stepwise variable selection algorithm (n = 1000). Eight variables were age at controlled ovarian hyperstimulation (COH), reason for freezing, AH, endometrial thickness, damaged blastomere, number of embryos transferred, number of good-quality embryos, and blood presence on transfer catheter. A descriptive comparison of the relative importance was accomplished by the proportion of explained variation (PEV). Among the reasons for freezing, the OHSS group showed a higher OR than the surplus embryo group when compared with other reasons for VET groups (OHSS versus Other, OR: 2.145; CI: 1.4-3.286; Surplus embryos versus Other, OR: 1.152; CI: 0.761-1.743) and high PEV (marginal 2.77%, P = 0.2911; partial 1.68%; CI of area under receptor operator characteristic curve (ROC): 0.5576-0.6000). AH also showed a high OR (OR: 2.105, CI: 1.554-2.85) and high PEV (marginal 1.97%; partial 1.02%; CI of area under ROC: 0.5344-0.5647). The number of good-quality embryos showed the highest marginal PEV and partial PEV (marginal 3.91%, partial 2.28%; CI of area under ROC: 0.5886-0.6343). This was a retrospective multivariate analysis of the data obtained in 5 years from a single IVF center. Repeated cycles in the same woman were treated as independent observations, which could introduce bias. Results are based on clinical pregnancy and not live births. Prospective analysis of a larger data set from a multicenter study based on live births is necessary to confirm the findings. Paying attention to the quality of embryos, the number of good embryos, AH and the reasons for freezing that are associated with clinical pregnancy after VET will assist the improvement of success rates.

Work experience, job-fulfillment and burnout among VMMC providers in Kenya, South Africa, Tanzania and Zimbabwe.

PubMed

Perry, Linnea; Rech, Dino; Mavhu, Webster; Frade, Sasha; Machaku, Michael D; Onyango, Mathews; Aduda, Dickens S Omondi; Fimbo, Bennett; Cherutich, Peter; Castor, Delivette; Njeuhmeli, Emmanuel; Bertrand, Jane T

2014-01-01

Human resource capacity is vital to the scale-up of voluntary medical male circumcision (VMMC) services. VMMC providers are at risk of "burnout" from performing a single task repeatedly in a high volume work environment that produces long work hours and intense work effort. The Systematic Monitoring of the Voluntary Medical Male Circumcision Scale-up (SYMMACS) surveyed VMMC providers in Kenya, South Africa, Tanzania, and Zimbabwe in 2011 (n = 357) and 2012 (n = 591). Providers self-reported on their training, work experience, levels of job-fulfillment and work fatigue/burnout. Data analysis included a descriptive analysis of VMMC provider characteristics, and both bivariate and multivariate analyses of factors associated with provider work fatigue/burnout. In 2012, Kenyan providers had worked in VMMC for a median of 31 months compared to South Africa (10 months), Tanzania (15 months), and Zimbabwe (11 months). More than three-quarters (78 - 99%) of providers in all countries in 2012 reported that VMMC is a personally fulfilling job. However, 67% of Kenyan providers reported starting to experience work fatigue/burnout compared to South Africa (33%), Zimbabwe (17%), and Tanzania (15%). Despite the high level of work fatigue/burnout in Kenya, none of the measured factors (i.e., gender, age, full-time versus part-time status, length of service, number of operations performed, or cadre) were significantly associated with work fatigue/burnout in 2011. In 2012, logistic regression found increases in age (p<.05) and number of months working in VMMC (p<.01) were associated with an increased likelihood of experiencing work fatigue/burnout, while higher career total VMMCs decreased the likelihood of experiencing burnout. Given cross-country differences, further elucidation of cultural and other contextual factors that may influence provider burnout is required. Continuing to emphasize the contribution that providers make in the fight against HIV/AIDS is important.

Work Experience, Job-Fulfillment and Burnout among VMMC Providers in Kenya, South Africa, Tanzania and Zimbabwe

PubMed Central

Perry, Linnea; Rech, Dino; Mavhu, Webster; Frade, Sasha; Machaku, Michael D.; Onyango, Mathews; Aduda, Dickens S. Omondi.; Fimbo, Bennett; Cherutich, Peter; Castor, Delivette; Njeuhmeli, Emmanuel; Bertrand, Jane T.

2014-01-01

Background Human resource capacity is vital to the scale-up of voluntary medical male circumcision (VMMC) services. VMMC providers are at risk of “burnout” from performing a single task repeatedly in a high volume work environment that produces long work hours and intense work effort. Methods and findings The Systematic Monitoring of the Voluntary Medical Male Circumcision Scale-up (SYMMACS) surveyed VMMC providers in Kenya, South Africa, Tanzania, and Zimbabwe in 2011 (n = 357) and 2012 (n = 591). Providers self-reported on their training, work experience, levels of job-fulfillment and work fatigue/burnout. Data analysis included a descriptive analysis of VMMC provider characteristics, and both bivariate and multivariate analyses of factors associated with provider work fatigue/burnout. In 2012, Kenyan providers had worked in VMMC for a median of 31 months compared to South Africa (10 months), Tanzania (15 months), and Zimbabwe (11 months). More than three-quarters (78 – 99%) of providers in all countries in 2012 reported that VMMC is a personally fulfilling job. However, 67% of Kenyan providers reported starting to experience work fatigue/burnout compared to South Africa (33%), Zimbabwe (17%), and Tanzania (15%). Despite the high level of work fatigue/burnout in Kenya, none of the measured factors (i.e., gender, age, full-time versus part-time status, length of service, number of operations performed, or cadre) were significantly associated with work fatigue/burnout in 2011. In 2012, logistic regression found increases in age (p<.05) and number of months working in VMMC (p<.01) were associated with an increased likelihood of experiencing work fatigue/burnout, while higher career total VMMCs decreased the likelihood of experiencing burnout. Conclusion Given cross-country differences, further elucidation of cultural and other contextual factors that may influence provider burnout is required. Continuing to emphasize the contribution that providers make in the fight against HIV/AIDS is important. PMID:24802260

Streamflow characterization using functional data analysis of the Potomac River

NASA Astrophysics Data System (ADS)

Zelmanow, A.; Maslova, I.; Ticlavilca, A. M.; McKee, M.

2013-12-01

Flooding and droughts are extreme hydrological events that affect the United States economically and socially. The severity and unpredictability of flooding has caused billions of dollars in damage and the loss of lives in the eastern United States. In this context, there is an urgent need to build a firm scientific basis for adaptation by developing and applying new modeling techniques for accurate streamflow characterization and reliable hydrological forecasting. The goal of this analysis is to use numerical streamflow characteristics in order to classify, model, and estimate the likelihood of extreme events in the eastern United States, mainly the Potomac River. Functional data analysis techniques are used to study yearly streamflow patterns, with the extreme streamflow events characterized via functional principal component analysis. These methods are merged with more classical techniques such as cluster analysis, classification analysis, and time series modeling. The developed functional data analysis approach is used to model continuous streamflow hydrographs. The forecasting potential of this technique is explored by incorporating climate factors to produce a yearly streamflow outlook.

A Game Theoretical Approach to Hacktivism: Is Attack Likelihood a Product of Risks and Payoffs?

PubMed

Bodford, Jessica E; Kwan, Virginia S Y

2018-02-01

The current study examines hacktivism (i.e., hacking to convey a moral, ethical, or social justice message) through a general game theoretic framework-that is, as a product of costs and benefits. Given the inherent risk of carrying out a hacktivist attack (e.g., legal action, imprisonment), it would be rational for the user to weigh these risks against perceived benefits of carrying out the attack. As such, we examined computer science students' estimations of risks, payoffs, and attack likelihood through a game theoretic design. Furthermore, this study aims at constructing a descriptive profile of potential hacktivists, exploring two predicted covariates of attack decision making, namely, peer prevalence of hacking and sex differences. Contrary to expectations, results suggest that participants' estimations of attack likelihood stemmed solely from expected payoffs, rather than subjective risks. Peer prevalence significantly predicted increased payoffs and attack likelihood, suggesting an underlying descriptive norm in social networks. Notably, we observed no sex differences in the decision to attack, nor in the factors predicting attack likelihood. Implications for policymakers and the understanding and prevention of hacktivism are discussed, as are the possible ramifications of widely communicated payoffs over potential risks in hacking communities.

The performance of blood pressure-to-height ratio as a screening measure for identifying children and adolescents with hypertension: a meta-analysis.

PubMed

Ma, Chunming; Liu, Yue; Lu, Qiang; Lu, Na; Liu, Xiaoli; Tian, Yiming; Wang, Rui; Yin, Fuzai

2016-02-01

The blood pressure-to-height ratio (BPHR) has been shown to be an accurate index for screening hypertension in children and adolescents. The aim of the present study was to perform a meta-analysis to assess the performance of BPHR for the assessment of hypertension. Electronic and manual searches were performed to identify studies of the BPHR. After methodological quality assessment and data extraction, pooled estimates of the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, area under the receiver operating characteristic curve and summary receiver operating characteristics were assessed systematically. The extent of heterogeneity for it was assessed. Six studies were identified for analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio values of BPHR, for assessment of hypertension, were 96% [95% confidence interval (CI)=0.95-0.97], 90% (95% CI=0.90-0.91), 10.68 (95% CI=8.03-14.21), 0.04 (95% CI=0.03-0.07) and 247.82 (95% CI=114.50-536.34), respectively. The area under the receiver operating characteristic curve was 0.9472. The BPHR had higher diagnostic accuracies for identifying hypertension in children and adolescents.

Accurate Structural Correlations from Maximum Likelihood Superpositions

PubMed Central

Theobald, Douglas L; Wuttke, Deborah S

2008-01-01

The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. Accurate analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly accurate technique for inferring the major modes of structural correlation in macromolecules using likelihood-based statistical analysis of sets of structures. This method is generally applicable to any ensemble of related molecules, including families of nuclear magnetic resonance (NMR) models, different crystal forms of a protein, and structural alignments of homologous proteins, as well as molecular dynamics trajectories. Dominant modes of structural correlation are determined using principal components analysis (PCA) of the maximum likelihood estimate of the correlation matrix. The correlations we identify are inherently independent of the statistical uncertainty and dynamic heterogeneity associated with the structural coordinates. We additionally present an easily interpretable method (“PCA plots”) for displaying these positional correlations by color-coding them onto a macromolecular structure. Maximum likelihood PCA of structural superpositions, and the structural PCA plots that illustrate the results, will facilitate the accurate determination of dynamic structural correlations analyzed in diverse fields of structural biology. PMID:18282091

Factors influencing unsafe behaviors and accidents on construction sites: a review.

PubMed

Khosravi, Yahya; Asilian-Mahabadi, Hassan; Hajizadeh, Ebrahim; Hassanzadeh-Rangi, Narmin; Bastani, Hamid; Behzadan, Amir H

2014-01-01

Construction is a hazardous occupation due to the unique nature of activities involved and the repetitiveness of several field behaviors. The aim of this methodological and theoretical review is to explore the empirical factors influencing unsafe behaviors and accidents on construction sites. In this work, results and findings from 56 related previous studies were investigated. These studies were categorized based on their design, type, methods of data collection, analytical methods, variables, and key findings. A qualitative content analysis procedure was used to extract variables, themes, and factors. In addition, all studies were reviewed to determine the quality rating and to evaluate the strength of provided evidence. The content analysis identified 8 main categories: (a) society, (b) organization, (c) project management, (d) supervision, (e) contractor, (f) site condition, (g) work group, and (h) individual characteristics. The review highlighted the importance of more distal factors, e.g., society and organization, and project management, that may contribute to reducing the likelihood of unsafe behaviors and accidents through the promotion of site condition and individual features (as proximal factors). Further research is necessary to provide a better understanding of the links between unsafe behavior theories and empirical findings, challenge theoretical assumptions, develop new applied theories, and make stronger recommendations.

Predictors and overestimation of recalled mobile phone use among children and adolescents.

PubMed

Aydin, Denis; Feychting, Maria; Schüz, Joachim; Andersen, Tina Veje; Poulsen, Aslak Harbo; Prochazka, Michaela; Klæboe, Lars; Kuehni, Claudia E; Tynes, Tore; Röösli, Martin

2011-12-01

A growing body of literature addresses possible health effects of mobile phone use in children and adolescents by relying on the study participants' retrospective reconstruction of mobile phone use. In this study, we used data from the international case-control study CEFALO to compare self-reported with objectively operator-recorded mobile phone use. The aim of the study was to assess predictors of level of mobile phone use as well as factors that are associated with overestimating own mobile phone use. For cumulative number and duration of calls as well as for time since first subscription we calculated the ratio of self-reported to operator-recorded mobile phone use. We used multiple linear regression models to assess possible predictors of the average number and duration of calls per day and logistic regression models to assess possible predictors of overestimation. The cumulative number and duration of calls as well as the time since first subscription of mobile phones were overestimated on average by the study participants. Likelihood to overestimate number and duration of calls was not significantly different for controls compared to cases (OR=1.1, 95%-CI: 0.5 to 2.5 and OR=1.9, 95%-CI: 0.85 to 4.3, respectively). However, likelihood to overestimate was associated with other health related factors such as age and sex. As a consequence, such factors act as confounders in studies relying solely on self-reported mobile phone use and have to be considered in the analysis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Global validation of the WSES Sepsis Severity Score for patients with complicated intra-abdominal infections: a prospective multicentre study (WISS Study).

PubMed

Sartelli, Massimo; Abu-Zidan, Fikri M; Catena, Fausto; Griffiths, Ewen A; Di Saverio, Salomone; Coimbra, Raul; Ordoñez, Carlos A; Leppaniemi, Ari; Fraga, Gustavo P; Coccolini, Federico; Agresta, Ferdinando; Abbas, Asrhaf; Abdel Kader, Saleh; Agboola, John; Amhed, Adamu; Ajibade, Adesina; Akkucuk, Seckin; Alharthi, Bandar; Anyfantakis, Dimitrios; Augustin, Goran; Baiocchi, Gianluca; Bala, Miklosh; Baraket, Oussama; Bayrak, Savas; Bellanova, Giovanni; Beltràn, Marcelo A; Bini, Roberto; Boal, Matthew; Borodach, Andrey V; Bouliaris, Konstantinos; Branger, Frederic; Brunelli, Daniele; Catani, Marco; Che Jusoh, Asri; Chichom-Mefire, Alain; Cocorullo, Gianfranco; Colak, Elif; Costa, David; Costa, Silvia; Cui, Yunfeng; Curca, Geanina Loredana; Curry, Terry; Das, Koray; Delibegovic, Samir; Demetrashvili, Zaza; Di Carlo, Isidoro; Drozdova, Nadezda; El Zalabany, Tamer; Enani, Mushira Abdulaziz; Faro, Mario; Gachabayov, Mahir; Giménez Maurel, Teresa; Gkiokas, Georgios; Gomes, Carlos Augusto; Gonsaga, Ricardo Alessandro Teixeira; Guercioni, Gianluca; Guner, Ali; Gupta, Sanjay; Gutierrez, Sandra; Hutan, Martin; Ioannidis, Orestis; Isik, Arda; Izawa, Yoshimitsu; Jain, Sumita A; Jokubauskas, Mantas; Karamarkovic, Aleksandar; Kauhanen, Saila; Kaushik, Robin; Kenig, Jakub; Khokha, Vladimir; Kim, Jae Il; Kong, Victor; Koshy, Renol; Krasniqi, Avidyl; Kshirsagar, Ashok; Kuliesius, Zygimantas; Lasithiotakis, Konstantinos; Leão, Pedro; Lee, Jae Gil; Leon, Miguel; Lizarazu Pérez, Aintzane; Lohsiriwat, Varut; López-Tomassetti Fernandez, Eudaldo; Lostoridis, Eftychios; Mn, Raghuveer; Major, Piotr; Marinis, Athanasios; Marrelli, Daniele; Martinez-Perez, Aleix; Marwah, Sanjay; McFarlane, Michael; Melo, Renato Bessa; Mesina, Cristian; Michalopoulos, Nick; Moldovanu, Radu; Mouaqit, Ouadii; Munyika, Akutu; Negoi, Ionut; Nikolopoulos, Ioannis; Nita, Gabriela Elisa; Olaoye, Iyiade; Omari, Abdelkarim; Ossa, Paola Rodríguez; Ozkan, Zeynep; Padmakumar, Ramakrishnapillai; Pata, Francesco; Pereira Junior, Gerson Alves; Pereira, Jorge; Pintar, Tadeja; Pouggouras, Konstantinos; Prabhu, Vinod; Rausei, Stefano; Rems, Miran; Rios-Cruz, Daniel; Sakakushev, Boris; Sánchez de Molina, Maria Luisa; Seretis, Charampolos; Shelat, Vishal; Simões, Romeo Lages; Sinibaldi, Giovanni; Skrovina, Matej; Smirnov, Dmitry; Spyropoulos, Charalampos; Tepp, Jaan; Tezcaner, Tugan; Tolonen, Matti; Torba, Myftar; Ulrych, Jan; Uzunoglu, Mustafa Yener; van Dellen, David; van Ramshorst, Gabrielle H; Vasquez, Giorgio; Venara, Aurélien; Vereczkei, Andras; Vettoretto, Nereo; Vlad, Nutu; Yadav, Sanjay Kumar; Yilmaz, Tonguç Utku; Yuan, Kuo-Ching; Zachariah, Sanoop Koshy; Zida, Maurice; Zilinskas, Justas; Ansaloni, Luca

2015-01-01

To validate a new practical Sepsis Severity Score for patients with complicated intra-abdominal infections (cIAIs) including the clinical conditions at the admission (severe sepsis/septic shock), the origin of the cIAIs, the delay in source control, the setting of acquisition and any risk factors such as age and immunosuppression. The WISS study (WSES cIAIs Score Study) is a multicenter observational study underwent in 132 medical institutions worldwide during a four-month study period (October 2014-February 2015). Four thousand five hundred thirty-three patients with a mean age of 51.2 years (range 18-99) were enrolled in the WISS study. Univariate analysis has shown that all factors that were previously included in the WSES Sepsis Severity Score were highly statistically significant between those who died and those who survived (p < 0.0001). The multivariate logistic regression model was highly significant (p < 0.0001, R2 = 0.54) and showed that all these factors were independent in predicting mortality of sepsis. Receiver Operator Curve has shown that the WSES Severity Sepsis Score had an excellent prediction for mortality. A score above 5.5 was the best predictor of mortality having a sensitivity of 89.2 %, a specificity of 83.5 % and a positive likelihood ratio of 5.4. WSES Sepsis Severity Score for patients with complicated Intra-abdominal infections can be used on global level. It has shown high sensitivity, specificity, and likelihood ratio that may help us in making clinical decisions.

Maximum Likelihood Analysis of Nonlinear Structural Equation Models with Dichotomous Variables

ERIC Educational Resources Information Center

Song, Xin-Yuan; Lee, Sik-Yum

2005-01-01

In this article, a maximum likelihood approach is developed to analyze structural equation models with dichotomous variables that are common in behavioral, psychological and social research. To assess nonlinear causal effects among the latent variables, the structural equation in the model is defined by a nonlinear function. The basic idea of the…

The Neural Bases of Difficult Speech Comprehension and Speech Production: Two Activation Likelihood Estimation (ALE) Meta-Analyses

ERIC Educational Resources Information Center

Adank, Patti

2012-01-01

The role of speech production mechanisms in difficult speech comprehension is the subject of on-going debate in speech science. Two Activation Likelihood Estimation (ALE) analyses were conducted on neuroimaging studies investigating difficult speech comprehension or speech production. Meta-analysis 1 included 10 studies contrasting comprehension…

Comparison of standard maximum likelihood classification and polytomous logistic regression used in remote sensing

Treesearch

John Hogland; Nedret Billor; Nathaniel Anderson

2013-01-01

Discriminant analysis, referred to as maximum likelihood classification within popular remote sensing software packages, is a common supervised technique used by analysts. Polytomous logistic regression (PLR), also referred to as multinomial logistic regression, is an alternative classification approach that is less restrictive, more flexible, and easy to interpret. To...

A likelihood-based time series modeling approach for application in dendrochronology to examine the growth-climate relations and forest disturbance history

EPA Science Inventory

A time series intervention analysis (TSIA) of dendrochronological data to infer the tree growth-climate-disturbance relations and forest disturbance history is described. Maximum likelihood is used to estimate the parameters of a structural time series model with components for ...

Robust analysis of semiparametric renewal process models

PubMed Central

Lin, Feng-Chang; Truong, Young K.; Fine, Jason P.

2013-01-01

Summary A rate model is proposed for a modulated renewal process comprising a single long sequence, where the covariate process may not capture the dependencies in the sequence as in standard intensity models. We consider partial likelihood-based inferences under a semiparametric multiplicative rate model, which has been widely studied in the context of independent and identical data. Under an intensity model, gap times in a single long sequence may be used naively in the partial likelihood with variance estimation utilizing the observed information matrix. Under a rate model, the gap times cannot be treated as independent and studying the partial likelihood is much more challenging. We employ a mixing condition in the application of limit theory for stationary sequences to obtain consistency and asymptotic normality. The estimator's variance is quite complicated owing to the unknown gap times dependence structure. We adapt block bootstrapping and cluster variance estimators to the partial likelihood. Simulation studies and an analysis of a semiparametric extension of a popular model for neural spike train data demonstrate the practical utility of the rate approach in comparison with the intensity approach. PMID:24550568

Maximum likelihood estimation for Cox's regression model under nested case-control sampling.

PubMed

Scheike, Thomas H; Juul, Anders

2004-04-01

Nested case-control sampling is designed to reduce the costs of large cohort studies. It is important to estimate the parameters of interest as efficiently as possible. We present a new maximum likelihood estimator (MLE) for nested case-control sampling in the context of Cox's proportional hazards model. The MLE is computed by the EM-algorithm, which is easy to implement in the proportional hazards setting. Standard errors are estimated by a numerical profile likelihood approach based on EM aided differentiation. The work was motivated by a nested case-control study that hypothesized that insulin-like growth factor I was associated with ischemic heart disease. The study was based on a population of 3784 Danes and 231 cases of ischemic heart disease where controls were matched on age and gender. We illustrate the use of the MLE for these data and show how the maximum likelihood framework can be used to obtain information additional to the relative risk estimates of covariates.

Epidemiologic programs for computers and calculators. A microcomputer program for multiple logistic regression by unconditional and conditional maximum likelihood methods.

PubMed

Campos-Filho, N; Franco, E L

1989-02-01

A frequent procedure in matched case-control studies is to report results from the multivariate unmatched analyses if they do not differ substantially from the ones obtained after conditioning on the matching variables. Although conceptually simple, this rule requires that an extensive series of logistic regression models be evaluated by both the conditional and unconditional maximum likelihood methods. Most computer programs for logistic regression employ only one maximum likelihood method, which requires that the analyses be performed in separate steps. This paper describes a Pascal microcomputer (IBM PC) program that performs multiple logistic regression by both maximum likelihood estimation methods, which obviates the need for switching between programs to obtain relative risk estimates from both matched and unmatched analyses. The program calculates most standard statistics and allows factoring of categorical or continuous variables by two distinct methods of contrast. A built-in, descriptive statistics option allows the user to inspect the distribution of cases and controls across categories of any given variable.

Identifying a parsimonious model for predicting academic achievement in undergraduate medical education: A confirmatory factor analysis

PubMed Central

Ali, Syeda Kauser; Baig, Lubna Ansari; Violato, Claudio; Zahid, Onaiza

2017-01-01

Objectives: This study was conducted to adduce evidence of validity for admissions tests and processes and for identifying a parsimonious model that predicts students’ academic achievement in Medical College. Methods: Psychometric study done on admission data and assessment scores for five years of medical studies at Aga Khan University Medical College, Pakistan using confirmatory factor analysis (CFA) and structured equation modeling (SEM). Sample included 276 medical students admitted in 2003, 2004 and 2005. Results: The SEM supported the existence of covariance between verbal reasoning, science and clinical knowledge for predicting achievement in medical school employing Maximum Likelihood (ML) estimations (n=112). Fit indices: χ2 (21) = 59.70, p =<.0001; CFI=.873; RMSEA = 0.129; SRMR = 0.093. Conclusions: This study shows that in addition to biology and chemistry which have been traditionally used as major criteria for admission to medical colleges in Pakistan; mathematics has proven to be a better predictor for higher achievements in medical college. PMID:29067063

Propensity for Violence among Homeless and Runaway Adolescents: An Event History Analysis*

PubMed Central

Crawford, Devan M.; Whitbeck, Les B.; Hoyt, Dan R.

2012-01-01

Little is known about the prevalence of violent behaviors among homeless and runaway adolescents or the specific behavioral factors that influence violent behaviors across time. In this longitudinal study of 300 homeless and runaway adolescents aged 16–19 years at baseline, we use event history analysis to assess the factors associated with acts of violence over three years, controlling for individual propensities and time-varying behaviors. The results indicate that females, non-minorities, and non-heterosexuals were less likely to engage in violence across time. Those who met criteria for substance abuse disorders (i.e. alcohol abuse, alcohol dependence, drug abuse) were more likely to engage in violence. A history of caretaker abuse was associated with violent behaviors, as were street survival strategies such as selling drugs, participating in gang activity, and associating with deviant peers. Simply having spent time directly on the streets at any specific time point also increased the likelihood for violence. PMID:22865932

Identifying a parsimonious model for predicting academic achievement in undergraduate medical education: A confirmatory factor analysis.

PubMed

Ali, Syeda Kauser; Baig, Lubna Ansari; Violato, Claudio; Zahid, Onaiza

2017-01-01

This study was conducted to adduce evidence of validity for admissions tests and processes and for identifying a parsimonious model that predicts students' academic achievement in Medical College. Psychometric study done on admission data and assessment scores for five years of medical studies at Aga Khan University Medical College, Pakistan using confirmatory factor analysis (CFA) and structured equation modeling (SEM). Sample included 276 medical students admitted in 2003, 2004 and 2005. The SEM supported the existence of covariance between verbal reasoning, science and clinical knowledge for predicting achievement in medical school employing Maximum Likelihood (ML) estimations (n=112). Fit indices: χ 2 (21) = 59.70, p =<.0001; CFI=.873; RMSEA = 0.129; SRMR = 0.093. This study shows that in addition to biology and chemistry which have been traditionally used as major criteria for admission to medical colleges in Pakistan; mathematics has proven to be a better predictor for higher achievements in medical college.

Development and Validation of the Mathematical Resilience Scale

ERIC Educational Resources Information Center

Kooken, Janice; Welsh, Megan E.; McCoach, D. Betsy; Johnston-Wilder, Sue; Lee, Clare

2016-01-01

The Mathematical Resilience Scale measures students' attitudes toward studying mathematics, using three correlated factors: Value, Struggle, and Growth. The Mathematical Resilience Scale was developed and validated using exploratory and confirmatory factor analyses across three samples. Results provide a new approach to gauge the likelihood of…

Constructing the Japanese version of the Maslach Burnout Inventory-Student Survey: Confirmatory factor analysis.

PubMed

Tsubakita, Takashi; Shimazaki, Kazuyo

2016-01-01

To examine the factorial validity of the Maslach Burnout Inventory-Student Survey, using a sample of 2061 Japanese university students majoring in the medical and natural sciences (67.9% male, 31.8% female; Mage  = 19.6 years, standard deviation = 1.5). The back-translated scale used unreversed items to assess inefficacy. The inventory's descriptive properties and Cronbach's alphas were calculated using SPSS software. The present authors compared fit indices of the null, one factor, and default three factor models via confirmatory factor analysis with maximum-likelihood estimation using AMOS software, version 21.0. Intercorrelations between exhaustion, cynicism, and inefficacy were relatively higher than in prior studies. Cronbach's alphas were 0.76, 0.85, and 0.78, respectively. Although fit indices of the hypothesized three factor model did not meet the respective criteria, the model demonstrated better fit than did the null and one factor models. The present authors added four paths between error variables within items, but the modified model did not show satisfactory fit. Subsequent analysis revealed that a bi-factor model fit the data better than did the hypothesized or modified three factor models. The Japanese version of the Maslach Burnout Inventory-Student Survey needs minor changes to improve the fit of its three factor model, but the scale as a whole can be used to adequately assess overall academic burnout in Japanese university students. Although the scale was back-translated, two items measuring exhaustion whose expressions overlapped should be modified, and all items measuring inefficacy should be reversed in order to statistically clarify the factorial difference between the scale's three factors. © 2015 The Authors. Japan Journal of Nursing Science © 2015 Japan Academy of Nursing Science.

Value of circulating cell-free DNA analysis as a diagnostic tool for breast cancer: a meta-analysis

PubMed Central

Ma, Xuelei; Zhang, Jing; Hu, Xiuying

2017-01-01

Objectives The aim of this study was to systematically evaluate the diagnostic value of cell free DNA (cfDNA) for breast cancer. Results Among 308 candidate articles, 25 with relevant diagnostic screening qualified for final analysis. The mean sensitivity, specificity and area under the curve (AUC) of SROC plots for 24 studies that distinguished breast cancer patients from healthy controls were 0.70, 0.87, and 0.9314, yielding a DOR of 32.31. When analyzed in subgroups, the 14 quantitative studies produced sensitivity, specificity, AUC, and a DOR of 0.78, 0.83, 0.9116, and 24.40. The 10 qualitative studies produced 0.50, 0.98, 0.9919, and 68.45. For 8 studies that distinguished malignant breast cancer from benign diseases, the specificity, sensitivity, AUC and DOR were 0.75, 0.79, 0.8213, and 9.49. No covariate factors had a significant correlation with relative DOR. Deek's funnel plots indicated an absence of publication bias. Materials and Methods Databases were searched for studies involving the use of cfDNA to diagnose breast cancer. The studies were analyzed to determine sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (SROC). Covariates were evaluated for effect on relative DOR. Deek's Funnel plots were generated to measure publication bias. Conclusions Our analysis suggests a promising diagnostic potential of using cfDNA for breast cancer screening, but this diagnostic method is not yet independently sufficient. Further work refining qualitative cfDNA assays will improve the correct diagnosis of breast cancers. PMID:28460452

A comparison of cosegregation analysis methods for the clinical setting.

PubMed

Rañola, John Michael O; Liu, Quanhui; Rosenthal, Elisabeth A; Shirts, Brian H

2018-04-01

Quantitative cosegregation analysis can help evaluate the pathogenicity of genetic variants. However, genetics professionals without statistical training often use simple methods, reporting only qualitative findings. We evaluate the potential utility of quantitative cosegregation in the clinical setting by comparing three methods. One thousand pedigrees each were simulated for benign and pathogenic variants in BRCA1 and MLH1 using United States historical demographic data to produce pedigrees similar to those seen in the clinic. These pedigrees were analyzed using two robust methods, full likelihood Bayes factors (FLB) and cosegregation likelihood ratios (CSLR), and a simpler method, counting meioses. Both FLB and CSLR outperform counting meioses when dealing with pathogenic variants, though counting meioses is not far behind. For benign variants, FLB and CSLR greatly outperform as counting meioses is unable to generate evidence for benign variants. Comparing FLB and CSLR, we find that the two methods perform similarly, indicating that quantitative results from either of these methods could be combined in multifactorial calculations. Combining quantitative information will be important as isolated use of cosegregation in single families will yield classification for less than 1% of variants. To encourage wider use of robust cosegregation analysis, we present a website ( http://www.analyze.myvariant.org ) which implements the CSLR, FLB, and Counting Meioses methods for ATM, BRCA1, BRCA2, CHEK2, MEN1, MLH1, MSH2, MSH6, and PMS2. We also present an R package, CoSeg, which performs the CSLR analysis on any gene with user supplied parameters. Future variant classification guidelines should allow nuanced inclusion of cosegregation evidence against pathogenicity.

Discriminant analysis for predictor of falls in stroke patients by using the Berg Balance Scale.

PubMed

Maeda, Noriaki; Urabe, Yukio; Murakami, Masahito; Itotani, Keisuke; Kato, Junichi

2015-05-01

An observational study was carried out to estimate the strength of the relationships among balance, mobility and falls in hemiplegic stroke inpatients. The objective was to examine factors that may aid in the prediction of the likelihood of falls in stroke patients. A total of 53 stroke patients (30 male, 23 female) aged 67.0 ± 11.1 years were interviewed regarding their fall history. Physical performance was assessed using the Berg Balance Scale (BBS) and the Functional Independence Measure (FIM) scale. Variables that differed between fallers and non-fallers were identified, and a discriminant function analysis was carried out to determine the combination of variables that effectively predicted fall status. Of the 53 stroke patients, 19 were fallers. Compared with the non-fallers, the fallers scored low on the FIM, and differed with respect to age, time from stroke onset, length of hospital stay, Brunnstrom recovery stage and admission BBS score. Discriminant analysis for predicting falls in stroke patients showed that admission BBS score was significantly related to the likelihood of falls. Moreover, discriminant analysis showed that the use of a significant BBS score to classify fallers and non-fallers had an accuracy of 81.1%. The discriminating criterion between the two groups was a score of 31 points on the BBS. The results of this study suggest that BBS score is a strong predictor of falls in stroke patients. As balance is closely related to the risk of falls in hospitalised stroke patients, BBS might be useful in the prediction of falls.

Estimating hazard ratios in cohort data with missing disease information due to death.

PubMed

Binder, Nadine; Herrnböck, Anne-Sophie; Schumacher, Martin

2017-03-01

In clinical and epidemiological studies information on the primary outcome of interest, that is, the disease status, is usually collected at a limited number of follow-up visits. The disease status can often only be retrieved retrospectively in individuals who are alive at follow-up, but will be missing for those who died before. Right-censoring the death cases at the last visit (ad-hoc analysis) yields biased hazard ratio estimates of a potential risk factor, and the bias can be substantial and occur in either direction. In this work, we investigate three different approaches that use the same likelihood contributions derived from an illness-death multistate model in order to more adequately estimate the hazard ratio by including the death cases into the analysis: a parametric approach, a penalized likelihood approach, and an imputation-based approach. We investigate to which extent these approaches allow for an unbiased regression analysis by evaluating their performance in simulation studies and on a real data example. In doing so, we use the full cohort with complete illness-death data as reference and artificially induce missing information due to death by setting discrete follow-up visits. Compared to an ad-hoc analysis, all considered approaches provide less biased or even unbiased results, depending on the situation studied. In the real data example, the parametric approach is seen to be too restrictive, whereas the imputation-based approach could almost reconstruct the original event history information. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exposure enriched outcome dependent designs for longitudinal studies of gene-environment interaction.

PubMed

Sun, Zhichao; Mukherjee, Bhramar; Estes, Jason P; Vokonas, Pantel S; Park, Sung Kyun

2017-08-15

Joint effects of genetic and environmental factors have been increasingly recognized in the development of many complex human diseases. Despite the popularity of case-control and case-only designs, longitudinal cohort studies that can capture time-varying outcome and exposure information have long been recommended for gene-environment (G × E) interactions. To date, literature on sampling designs for longitudinal studies of G × E interaction is quite limited. We therefore consider designs that can prioritize a subsample of the existing cohort for retrospective genotyping on the basis of currently available outcome, exposure, and covariate data. In this work, we propose stratified sampling based on summaries of individual exposures and outcome trajectories and develop a full conditional likelihood approach for estimation that adjusts for the biased sample. We compare the performance of our proposed design and analysis with combinations of different sampling designs and estimation approaches via simulation. We observe that the full conditional likelihood provides improved estimates for the G × E interaction and joint exposure effects over uncorrected complete-case analysis, and the exposure enriched outcome trajectory dependent design outperforms other designs in terms of estimation efficiency and power for detection of the G × E interaction. We also illustrate our design and analysis using data from the Normative Aging Study, an ongoing longitudinal cohort study initiated by the Veterans Administration in 1963. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Beyond douching: use of feminine hygiene products and STI risk among young women.

PubMed

Ott, Mary A; Ofner, Susan; Fortenberry, J Dennis

2009-05-01

Use of feminine hygiene products (feminine wipes, sprays, douches, and yeast creams) by adolescent women is common, yet understudied. We examine the association among these genital hygiene behaviors, condom use, and sexually transmitted infection (STI). Using the interview as our unit of analysis, we examined associations between genital hygiene behaviors (use of feminine wipes, feminine sprays, douches, or yeast creams), STI risk factors, and infection with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. We recruited 295 adolescent women from primary care clinics as part of a larger longitudinal study of STI among high-risk adolescents. Participants completed face-to-face interviews every 3 months, and provided vaginal swabs for STI testing. Data were analyzed with repeated measures logistic models to control for multiple observations contributed by each participant. Participants reported douching in 25% of interviews, feminine sprays in 29%, feminine wipes in 27%, and yeast creams in 19% of interviews. We observed a co-occurrence of douching, spraying, and wiping. A past STI (6 months or more prior) was associated with increased likelihood of yeast cream use, and a recent STI (3 months prior) was associated with increased likelihood of feminine wipe use. Condom use was modestly associated with increased likelihood of douching. Young women frequently use feminine hygiene products, and it is important for clinicians to inquire about use as these products may mimic or mask STI. We found no associations between douching and STI, but instead modest associations between hygiene and STI prevention, suggesting motivation for self-care.

Rural health care bypass behavior: how community and spatial characteristics affect primary health care selection.

PubMed

Sanders, Scott R; Erickson, Lance D; Call, Vaughn R A; McKnight, Matthew L; Hedges, Dawson W

2015-01-01

(1) To assess the prevalence of rural primary care physician (PCP) bypass, a behavior in which residents travel farther than necessary to obtain health care, (2) To examine the role of community and non-health-care-related characteristics on bypass behavior, and (3) To analyze spatial bypass patterns to determine which rural communities are most affected by bypass. Data came from the Montana Health Matters survey, which gathered self-reported information from Montana residents on their health care utilization, satisfaction with health care services, and community and demographic characteristics. Logistic regression and spatial analysis were used to examine the probability and spatial patterns of bypass. Overall, 39% of respondents bypass local health care. Similar to previous studies, dissatisfaction with local health care was found to increase the likelihood of bypass. Dissatisfaction with local shopping also increases the likelihood of bypass, while the number of friends in a community, and commonality with community reduce the likelihood of bypass. Other significant factors associated with bypass include age, income, health, and living in a highly rural community or one with high commuting flows. Our results suggest that outshopping theory, in which patients bundle services and shopping for added convenience, extends to primary health care selection. This implies that rural health care selection is multifaceted, and that in addition to perceived satisfaction with local health care, the quality of local shopping and levels of community attachment also influence bypass behavior. © 2014 National Rural Health Association.

optBINS: Optimal Binning for histograms

NASA Astrophysics Data System (ADS)

Knuth, Kevin H.

2018-03-01

optBINS (optimal binning) determines the optimal number of bins in a uniform bin-width histogram by deriving the posterior probability for the number of bins in a piecewise-constant density model after assigning a multinomial likelihood and a non-informative prior. The maximum of the posterior probability occurs at a point where the prior probability and the the joint likelihood are balanced. The interplay between these opposing factors effectively implements Occam's razor by selecting the most simple model that best describes the data.

Clinical trials in Brazilian journals of ophthalmology: where we are.

PubMed

Lira, Rodrigo Pessoa Cavalcanti; Leal, Franz Schubert; Gonçalves, Fauze Abdulmassih; Amorim, Fernando Henrique Ramos; Felix, João Paulo Fernandes; Arieta, Carlos Eduardo Leite

2013-01-01

To compare clinical trials published in Brazilian journals of ophthalmology and in foreign journals of ophthalmology with respect to the number of citations and the quality of reporting [by applying the Consolidated Standards for Reporting Trials (CONSORT) statement writing standards]. The sample of this systematic review comprised the two Brazilian journals of ophthalmology indexed at Science Citation Index Expanded and six of the foreign journals of ophthalmology with highest Impact Factor® according ISI. All clinical trials (CTs) published from January 2009 to December 2010 at the Brazilians journals and a 1:1 randomized sample of the foreign journals were included. The primary outcome was the number of citations through the end of 2011. Subgroup analysis included language. The secondary outcome included likelihood of citation (cited at least once versus no citation), and presence or absence of CONSORT statement indicators. The citation counts were statistically significantly higher (P<0.001) in the Foreign Group (10.50) compared with the Brazilian Group (0.45). The likelihood citation was statistically significantly higher (P<0.001) in the Foreign Group (20/20 - 100%) compared with the Brazilian Group (8/20 - 40%). The subgroup analysis of the language influence in Brazilian articles showed that the citation counts were statistically significantly higher in the papers published in English (P<0.04). Of 37 possible CONSORT items, the mean for the Foreign Group was 20.55 and for the Brazilian Group was 13.65 (P<0.003). The number of citations and the quality of reporting of clinical trials in Brazilian journals of ophthalmology still are low when compared with the foreign journals of ophthalmology with highest Impact Factor®.

Outcomes after management of young women with cervical intraepithelial neoplasia 2 with a 6-month observation protocol.

PubMed

Bleecker, Elizabeth; Koehler, Elizabeth; Smith, Jennifer; Budwit, Debra; Rahangdale, Lisa

2014-01-01

Recommendations regarding treatment of cervical intraepithelial neoplasia (CIN) 2 in women have evolved over the years: young women with CIN 2 may be offered observation with Pap smears and colposcopy every 6 months instead of immediate excision or ablation of disease. The purpose of this study was to observe patient follow-up during the initiation of this management protocol for young women with CIN 2. This was a retrospective review of clinical outcomes of women younger than 30 years with CIN 2 on index biopsy and planned follow-up at UNC between July 2009 and August 2010. A chart review for clinical variables, follow-up visits, and progression of disease was conducted. Primary analysis determined the rate of follow-up and pathology at 6 months. Secondary analysis investigated risk factors for incomplete follow-up. Seventy women met inclusion criteria; 46 were managed with observation. Twenty-eight (60.8%; 28/46) women completed a follow-up visit. Demographic and clinical variables did not reach statistical significance in predicting the likelihood of completion of a follow-up visit, although there was a trend toward greater follow-up in employed patients (odds ratio = 5.25, 95% confidence interval = 0.84-34.78). Approximately half (52.4%; 11/21) of women with a completed cervical biopsy demonstrated regression of disease during the study period. On the basis of these data, follow-up in this population was unpredictable based on basic demographic or clinical factors that we often use to judge likelihood of compliance with medical recommendations. The percentage of patients with regression at follow-up was as expected from the natural history of CIN 2.

Coverage and parental perceptions of influenza vaccination among parents of children aged 6 to 23 months in Hong Kong

PubMed Central

2013-01-01

Background The impact of influenza on young children can be severe and even fatal. Influenza vaccination (IV) has been shown to be effective in reducing complications of influenza among children. This study investigated the prevalence and factors of IV among children aged 6-23 months in Hong Kong. Methods A sample of 401 Chinese parents of children aged 6-23 months were interviewed at local Maternal and Child Health Centers. Socio-demographic information, variables related to Health Belief Model, including perceptions about the child’s chance of contracting influenza, perceived harm of influenza on children, perceived benefits and side-effects of IV, having received recommendations from health professionals to uptake IV, and IV behaviors of the children were measured. Multivariate analysis was used to examine factors associated with IV behaviors of children. Results Only 9% of the children had ever been vaccinated. Among those parents who had heard of IV (92.0%), substantial proportions perceived that IV could reduce the risk of influenza-induced complications (70.5%), hospitalization (70.5%) and death (65.9%). Relatively few of the participants believed that IV had no side effects (17.1%) and even less had been recommended by health care professionals to uptake IV (10.6%). Results from multivariate analysis showed that physician recommendations were associated with a higher likelihood for IV among younger children, whilst parental perceptions of the side effects of IV was associated with a lower likelihood for IV. Conclusion The prevalence of IV among children aged 6-23 months in Hong Kong was very low. Promotion of IV with the component of physician recommendations and parents’ knowledge about IV safety for this group is warranted. PMID:24171947

Birmingham COPD Cohort: a cross-sectional analysis of the factors associated with the likelihood of being in paid employment among people with COPD

PubMed Central

Rai, Kiran K; Jordan, Rachel E; Siebert, W Stanley; Sadhra, Steven S; Fitzmaurice, David A; Sitch, Alice J; Ayres, Jon G; Adab, Peymané

2017-01-01

Background Employment rates among those with chronic obstructive pulmonary disease (COPD) are lower than those without COPD, but little is known about the factors that affect COPD patients’ ability to work. Methods Multivariable analysis of the Birmingham COPD Cohort Study baseline data was used to assess the associations between lifestyle, clinical, and occupational characteristics and likelihood of being in paid employment among working-age COPD patients. Results In total, 608 of 1,889 COPD participants were of working age, of whom 248 (40.8%) were in work. Older age (60–64 years vs 30–49 years: odds ratio [OR] =0.28; 95% confidence interval [CI] =0.12–0.65), lower educational level (no formal qualification vs degree/higher level: OR =0.43; 95% CI =0.19–0.97), poorer prognostic score (highest vs lowest quartile of modified body mass index, airflow obstruction, dyspnea, and exercise (BODE) score: OR =0.10; 95% CI =0.03–0.33), and history of high occupational exposure to vapors, gases, dusts, or fumes (VGDF; high VGDF vs no VGDF exposure: OR =0.32; 95% CI =0.12–0.85) were associated with a lower probability of being employed. Only the degree of breathlessness of BODE was significantly associated with employment. Conclusion This is the first study to comprehensively assess the characteristics associated with employment in a community sample of people with COPD. Future interventions should focus on managing breathlessness and reducing occupational exposures to VGDF to improve the work capability among those with COPD. PMID:28138233

Approximate likelihood calculation on a phylogeny for Bayesian estimation of divergence times.

PubMed

dos Reis, Mario; Yang, Ziheng

2011-07-01

The molecular clock provides a powerful way to estimate species divergence times. If information on some species divergence times is available from the fossil or geological record, it can be used to calibrate a phylogeny and estimate divergence times for all nodes in the tree. The Bayesian method provides a natural framework to incorporate different sources of information concerning divergence times, such as information in the fossil and molecular data. Current models of sequence evolution are intractable in a Bayesian setting, and Markov chain Monte Carlo (MCMC) is used to generate the posterior distribution of divergence times and evolutionary rates. This method is computationally expensive, as it involves the repeated calculation of the likelihood function. Here, we explore the use of Taylor expansion to approximate the likelihood during MCMC iteration. The approximation is much faster than conventional likelihood calculation. However, the approximation is expected to be poor when the proposed parameters are far from the likelihood peak. We explore the use of parameter transforms (square root, logarithm, and arcsine) to improve the approximation to the likelihood curve. We found that the new methods, particularly the arcsine-based transform, provided very good approximations under relaxed clock models and also under the global clock model when the global clock is not seriously violated. The approximation is poorer for analysis under the global clock when the global clock is seriously wrong and should thus not be used. The results suggest that the approximate method may be useful for Bayesian dating analysis using large data sets.

The elaboration likelihood model and communication about food risks.

PubMed

Frewer, L J; Howard, C; Hedderley, D; Shepherd, R

1997-12-01

Factors such as hazard type and source credibility have been identified as important in the establishment of effective strategies for risk communication. The elaboration likelihood model was adapted to investigate the potential impact of hazard type, information source, and persuasive content of information on individual engagement in elaborative, or thoughtful, cognitions about risk messages. One hundred sixty respondents were allocated to one of eight experimental groups, and the effects of source credibility, persuasive content of information and hazard type were systematically varied. The impact of the different factors on beliefs about the information and elaborative processing examined. Low credibility was particularly important in reducing risk perceptions, although persuasive content and hazard type were also influential in determining whether elaborative processing occurred.

Simulating the effect of non-linear mode coupling in cosmological parameter estimation

NASA Astrophysics Data System (ADS)

Kiessling, A.; Taylor, A. N.; Heavens, A. F.

2011-09-01

Fisher Information Matrix methods are commonly used in cosmology to estimate the accuracy that cosmological parameters can be measured with a given experiment and to optimize the design of experiments. However, the standard approach usually assumes both data and parameter estimates are Gaussian-distributed. Further, for survey forecasts and optimization it is usually assumed that the power-spectrum covariance matrix is diagonal in Fourier space. However, in the low-redshift Universe, non-linear mode coupling will tend to correlate small-scale power, moving information from lower to higher order moments of the field. This movement of information will change the predictions of cosmological parameter accuracy. In this paper we quantify this loss of information by comparing naïve Gaussian Fisher matrix forecasts with a maximum likelihood parameter estimation analysis of a suite of mock weak lensing catalogues derived from N-body simulations, based on the SUNGLASS pipeline, for a 2D and tomographic shear analysis of a Euclid-like survey. In both cases, we find that the 68 per cent confidence area of the Ωm-σ8 plane increases by a factor of 5. However, the marginal errors increase by just 20-40 per cent. We propose a new method to model the effects of non-linear shear-power mode coupling in the Fisher matrix by approximating the shear-power distribution as a multivariate Gaussian with a covariance matrix derived from the mock weak lensing survey. We find that this approximation can reproduce the 68 per cent confidence regions of the full maximum likelihood analysis in the Ωm-σ8 plane to high accuracy for both 2D and tomographic weak lensing surveys. Finally, we perform a multiparameter analysis of Ωm, σ8, h, ns, w0 and wa to compare the Gaussian and non-linear mode-coupled Fisher matrix contours. The 6D volume of the 1σ error contours for the non-linear Fisher analysis is a factor of 3 larger than for the Gaussian case, and the shape of the 68 per cent confidence volume is modified. We propose that future Fisher matrix estimates of cosmological parameter accuracies should include mode-coupling effects.

Tumor necrosis factor α level in cerebrospinal fluid for bacterial and aseptic meningitis: a diagnostic meta-analysis.

PubMed

Lv, S; Zhao, J; Zhang, J; Kwon, S; Han, M; Bian, R; Fu, H; Zhang, Y; Pan, H

2014-08-01

In our previous study, tumor necrosis factor α (TNF-α) was identified as an effective target for sepsis patients (Int J Clin Pract, 68, 2014, 520). TNF-α in cerebrospinal fluid (CSF) was also investigated for its utility in the differential diagnosis of bacterial and aseptic meningitis. However, there has been neither definite nor convincing evidence so far. Here the overall diagnostic accuracy of TNF-α in differentiation between bacterial and aseptic meningitis was evaluated through the meta-analysis of diagnostic tests. The sensitivity, specificity and other measures of accuracy were pooled using random effect models. Summary receiver operating characteristic curves were used to assess overall test performance. Publication bias was evaluated using funnel plots, and sensitivity analysis was also introduced. A total of 21 studies involving bacterial meningitis (678) and aseptic meningitis (694) involved a total of 1372 patients. The pooled sensitivity and specificity for the TNF-α test were 0.83 [95% confidence interval (CI) 0.80-0.86, I(2)  = 65.1] and 0.92 (95% CI 0.89-0.94, I(2)  = 61.8), respectively. The positive likelihood ratio was 12.05 (95% CI 7.41-19.60, I(2)  = 36.5), the negative likelihood ratio was 0.17 (95% CI 0.13-0.24, I(2)  = 59.4), and TNF-α was significantly associated with bacterial meningitis, with a diagnostic odds ratio of 49.84 (95% CI 28.53-87.06, I(2)  = 47.9). The overall accuracy of the TNF-α test was very high with the area under the curve 0.9317. Publication bias was absent, and sensitivity analysis suggested that our results were highly stable. Our meta-analysis suggested that TNF-α could be recommended as a useful marker for diagnosis of bacterial meningitis and differential diagnosis between bacterial and aseptic meningitis with high sensitivity and specificity. Thus, hospitals should be encouraged to conduct TNF-α tests in CSF after lumbar puncture. © 2014 The Author(s) European Journal of Neurology © 2014 EAN.

Cosmological parameters from a re-analysis of the WMAP 7 year low-resolution maps

NASA Astrophysics Data System (ADS)

Finelli, F.; De Rosa, A.; Gruppuso, A.; Paoletti, D.

2013-06-01

Cosmological parameters from Wilkinson Microwave Anisotropy Probe (WMAP) 7 year data are re-analysed by substituting a pixel-based likelihood estimator to the one delivered publicly by the WMAP team. Our pixel-based estimator handles exactly intensity and polarization in a joint manner, allowing us to use low-resolution maps and noise covariance matrices in T, Q, U at the same resolution, which in this work is 3.6°. We describe the features and the performances of the code implementing our pixel-based likelihood estimator. We perform a battery of tests on the application of our pixel-based likelihood routine to WMAP publicly available low-resolution foreground-cleaned products, in combination with the WMAP high-ℓ likelihood, reporting the differences on cosmological parameters evaluated by the full WMAP likelihood public package. The differences are not only due to the treatment of polarization, but also to the marginalization over monopole and dipole uncertainties present in the WMAP pixel likelihood code for temperature. The credible central value for the cosmological parameters change below the 1σ level with respect to the evaluation by the full WMAP 7 year likelihood code, with the largest difference in a shift to smaller values of the scalar spectral index nS.

Adolescents' Attitudes on Smoking Are Related to Experimentation with Smoking, Daily Smoking and Best Friends' Smoking in Two Karelias in Finland and in Russia.

PubMed

Aura, Annamari; Laatikainen, Tiina; Isoaho, Hannu; Lazutkina, Galina; Tossavainen, Kerttu

2016-12-01

Becoming a smoker usually starts during adolescence and is a dynamic process involving experimentation before the establishment of daily smoking. It has been suggested that adolescents who smoke differ from those who do not in their attitudes to smoking. The purpose of this study was to find out whether attitudes related to smoking legislation and restrictions, social pressures in smoking and image of smokers are associated with smoking experimentation, daily smoking and best friends' smoking. The data were gathered with a self-administered questionnaire in North Karelia, Eastern Finland and in the Pitkyaranta district, Republic of Karelia, Russia. The respondents were 15-year-old 9th grade pupils in local schools. In Pitkyaranta, the data analyses covered pupils in all eight schools in the area (n = 179). In North Karelia, the data analyses comprised of selected eight schools (n = 601). Data were analysed with exploratory factor analysis. The models revealed that attitudes related to restrictions and social pressure were significantly associated with experimenting with smoking [OR (95 % CI) 7.923 (5.787-10.847)], daily smoking [OR (95 % CI) 9.575 (6.727-13.628)] and the likelihood of best friends' smoking [OR (95 % CI) 3.154 (2.579-3.858)]. The stronger the young peoples' attitudes and opinions, for example, towards restrictions and with more difficulties in refusing smoking, the higher the likelihood for smoking experimentations, daily smoking as well as the likelihood for their best friends' smoking. The country and factor interactions were not associated with smoking experimentations, daily smoking or best friends' smoking. Regardless of cultural background, adolescents who smoke have more positive attitudes to smoking, and perceive more social support for smoking, than do adolescents who do not smoke. The study stresses the similarity of the results in both Karelia's despite the enormous differences in culture, economy and public policy.

The effect of NACHRI children's hospital designation on outcome in pediatric malignant brain tumors.

PubMed

Donoho, Daniel A; Wen, Timothy; Liu, Jonathan; Zarabi, Hosniya; Christian, Eisha; Cen, Steven; Zada, Gabriel; McComb, J Gordon; Krieger, Mark D; Mack, William J; Attenello, Frank J

2017-08-01

OBJECTIVE Although current pediatric neurosurgery guidelines encourage the treatment of pediatric malignant brain tumors at specialized centers such as pediatric hospitals, there are limited data in support of this recommendation. Previous studies suggest that children treated by higher-volume surgeons and higher-volume hospitals may have better outcomes, but the effect of treatment at dedicated children's hospitals has not been investigated. METHODS The authors analyzed the Healthcare Cost and Utilization Project Kids' Inpatient Database (KID) from 2000-2009 and included all patients undergoing a craniotomy for malignant pediatric brain tumors based on ICD-9-CM codes. They investigated the effects of patient demographics, tumor location, admission type, and hospital factors on rates of routine discharge and mortality. RESULTS From 2000 through 2009, 83.6% of patients had routine discharges, and the in-hospital mortality rate was 1.3%. In multivariate analysis, compared with children treated at an institution designated as a pediatric hospital by NACHRI (National Association of Children's Hospitals and Related Institutions), children receiving treatment at a pediatric unit within an adult hospital (OR 0.5, p < 0.01) or a general hospital without a designated pediatric unit (OR 0.4, p < 0.01) were less likely to have routine discharges. Treatment at a large hospital (> 400 beds; OR 1.8, p = 0.02) and treatment at a teaching hospital (OR 1.7, p = 0.02) were independently associated with greater likelihood of routine discharge. However, patients transferred between facilities had a significantly decreased likelihood of routine discharge (OR 0.5, p < 0.01) and an increased likelihood of mortality (OR 5.0, p < 0.01). Procedural volume was not associated with rate of routine discharge or mortality. CONCLUSIONS These findings may have implications for planning systems of care for pediatric patients with malignant brain tumors. The authors hope to motivate future research into the specific factors that may lead to improved outcomes at designated pediatric hospitals.

Housing and Food Insecurity, Care Access, and Health Status Among the Chronically Ill: An Analysis of the Behavioral Risk Factor Surveillance System.

PubMed

Charkhchi, Paniz; Fazeli Dehkordy, Soudabeh; Carlos, Ruth C

2018-05-01

The proportion of the United States population with chronic illness continues to rise. Understanding the determinants of quality of care-particularly social determinants-is critical to the provision of care in this population. To estimate the prevalence of housing and food insecurity among persons with common chronic conditions and to assess the independent effects of chronic illness and sociodemographic characteristics on (1) housing and food insecurity, and (2) health care access hardship and health status. Cross-sectional study. We used data from the 11 states and one territory that completed the social context module of the 2015 Behavioral Risk Factor Surveillance System (BRFSS). We estimated the prevalence of housing and food insecurity among patients with cancer, stroke, cardiovascular disease, and chronic lung disease. Logistic regression models were used to assess the independent effects of housing and food insecurity, chronic conditions, and demographics on health care access and health status. Among the chronically ill, 36.71% (95% CI: 35.54-37.88) experienced housing insecurity and 30.60% (95% CI: 29.49-31.71) experienced food insecurity. Cardiovascular and lung disease increased the likelihood of housing (OR 1.69, 95% CI: 1.07-2.66 and OR 1.71, 95% CI: 1.12-2.60, respectively) and food insecurity (OR 1.75, 95% CI: 1.12-2.73 and OR 1.78, 95% CI: 1.20-2.63, respectively). Housing and food insecurity significantly increased the risk of health care access hardship. Being insured or having an income level above 200% of the federal poverty level significantly reduced the likelihood of access hardship, while female gender significantly increased the likelihood. Chronic illness independently affects housing and food insecurity. In turn, food and housing anxiety leads to reduced access to care, likely due to cost concerns, and correlates with poorer health. A more complete understanding of the pathways by which chronic illness influences social determinants and clinical outcomes is needed.

A study on reproductive performance and related factors of zebu cows in pastoral herds in a semi-arid area of Tanzania.

PubMed

Kanuya, N L; Matiko, M K; Kessy, B M; Mgongo, F O; Ropstad, E; Reksen, O

2006-06-01

A prospective longitudinal study was carried out from September 2001 to June 2004 in three adjacent villages in a semi-arid area of Tanzania. The objectives of this study were to measure the intervals between calving and either resumption of cyclical activity or confirmation of pregnancy, to estimate calving intervals, and to investigate the effect of factors assumed to be related to postpartum reproductive performance. A total of 275 lactation periods from 177 Tanzanian Shorthorn Zebu cows managed in a traditional pastoral system in 46 households were initially included. Animals were initially screened for brucelosis and thereafter examined by palpation per rectum at 2-week intervals. Body condition score (scale 1 to 5) was assessed and girth measurement (cm) taken. Occurrence of other reproductive events such as calving, abortion, death of calf, culling and reason for culling were recorded. In a subset of 98 lactation periods from 91 cows milk samples for progesterone (P4) determination were collected twice per week from day 7 after calving to the time of confirmed pregnancy or until milk production ceased before pregnancy. The data were analysed both univariately and in multivariable Cox proportional hazard (frailty) models. The mean (+/-S.E.M.) calving interval was 500+/-13.6 days. Positive reactors in the brucellosis test were 15.6% of the tested animals. Milk P4 analysis showed the rate of abortion/late embryo loss to be 14.3%. Calf mortality rates varied between 14.6 and 17.4%. A positive relationship was found between the outcome variables likelihood of cyclical activity and likelihood of pregnancy in the Cox model, and the explanatory variables: parity and body condition score (BCS) at calving. A negative relationship was found between the outcome variables, and the explanatory variables: maximum BCS loss and calf survival/mortality. Calving in the rainy season was associated with an increased likelihood of pregnancy.

Diagnostic Accuracy of Coronary Computed Tomography Before Aortic Valve Replacement: Systematic Review and Meta-Analysis.

PubMed

Chaikriangkrai, Kongkiat; Jhun, Hye Yeon; Shantha, Ghanshyam Palamaner Subash; Abdulhak, Aref Bin; Tandon, Rudhir; Alqasrawi, Musab; Klappa, Anthony; Pancholy, Samir; Deshmukh, Abhishek; Bhama, Jay; Sigurdsson, Gardar

2018-07-01

In aortic stenosis patients referred for surgical and transcatheter aortic valve replacement (AVR), the evidence of diagnostic accuracy of coronary computed tomography angiography (CCTA) has been limited. The objective of this study was to investigate the diagnostic accuracy of CCTA for significant coronary artery disease (CAD) in patients referred for AVR using invasive coronary angiography (ICA) as the gold standard. We searched databases for all diagnostic studies of CCTA in patients referred for AVR, which reported diagnostic testing characteristics on patient-based analysis required to pool summary sensitivity, specificity, positive-likelihood ratio, and negative-likelihood ratio. Significant CAD in both CCTA and ICA was defined by >50% stenosis in any coronary artery, coronary stent, or bypass graft. Thirteen studies evaluated 1498 patients (mean age, 74 y; 47% men; 76% transcatheter AVR). The pooled prevalence of significant stenosis determined by ICA was 43%. Hierarchical summary receiver-operating characteristic analysis demonstrated a summary area under curve of 0.96. The pooled sensitivity, specificity, and positive-likelihood and negative-likelihood ratios of CCTA in identifying significant stenosis determined by ICA were 95%, 79%, 4.48, and 0.06, respectively. In subgroup analysis, the diagnostic profiles of CCTA were comparable between surgical and transcatheter AVR. Despite the higher prevalence of significant CAD in patients with aortic stenosis than with other valvular heart diseases, our meta-analysis has shown that CCTA has a suitable diagnostic accuracy profile as a gatekeeper test for ICA. Our study illustrates a need for further study of the potential role of CCTA in preoperative planning for AVR.

Discontinued Information and Communication Technology Usage among Older Adults in Continuing Care Retirement Communities in the United States.

PubMed

Rikard, R V; Berkowsky, Ronald W; Cotten, Shelia R

2018-01-01

Older adults are increasingly using information and communication technologies (ICTs). Recent studies show beneficial effects of using ICTs for older adults, particularly in terms of reducing loneliness and depression. However, little is known about the factors that may prevent discontinued ICT use in populations that may be at greater risk, such as those in continuing care retirement communities (CCRCs). The purpose of this study is to examine a range of factors that may influence discontinued (1) ICT use, (2) searching for health information, and (3) searching for general information over time among CCRC residents. We use longitudinal data from a randomized controlled trial conducted with residents of 19 CCRCs. We use flexible parametric models to estimate the hazard ratio or hazard rate over 5 waves of data to determine what factors significantly predict discontinued (1) ICT use, (2) health information searching, and (3) general information searching. The analysis reveals that independent living residents who took part in an 8-week ICT training intervention were less likely to stop using ICTs. Age and the number of instrumental activities of daily living (IADL) impairments significantly predicted an increased likelihood of stopping ICT use. When examining specific ICT-related activities, the analysis reveals that independent living residents who took part in the ICT training intervention were less likely to stop searching for health information and general information online. In addition, age and the number of IADL impairments were associated with increased likelihood of discontinued health information searches and discontinued general information searches. ICT training interventions may motivate residents of CCRCs to stay connected by increasing the ICT skill level and promoting confidence, thus decreasing the probability that they will discontinue using ICTs and searching for general information. However, the effects of ICT training on motivating continued ICT usage may be more pronounced among independent living residents. Limitations in the number of IADL impairments is a key factor leading to discontinued use of ICTs among CCRC residents, suggesting that designers of ICTs should be cognizant of the cognitive and physical limitations among this group. © 2017 S. Karger AG, Basel.

Parametric Analysis of a Hover Test Vehicle using Advanced Test Generation and Data Analysis

NASA Technical Reports Server (NTRS)

Gundy-Burlet, Karen; Schumann, Johann; Menzies, Tim; Barrett, Tony

2009-01-01

Large complex aerospace systems are generally validated in regions local to anticipated operating points rather than through characterization of the entire feasible operational envelope of the system. This is due to the large parameter space, and complex, highly coupled nonlinear nature of the different systems that contribute to the performance of the aerospace system. We have addressed the factors deterring such an analysis by applying a combination of technologies to the area of flight envelop assessment. We utilize n-factor (2,3) combinatorial parameter variations to limit the number of cases, but still explore important interactions in the parameter space in a systematic fashion. The data generated is automatically analyzed through a combination of unsupervised learning using a Bayesian multivariate clustering technique (AutoBayes) and supervised learning of critical parameter ranges using the machine-learning tool TAR3, a treatment learner. Covariance analysis with scatter plots and likelihood contours are used to visualize correlations between simulation parameters and simulation results, a task that requires tool support, especially for large and complex models. We present results of simulation experiments for a cold-gas-powered hover test vehicle.

Alcohol consumption and the intention to engage in unprotected sex: systematic review and meta-analysis of experimental studies.

PubMed

Rehm, Jürgen; Shield, Kevin D; Joharchi, Narges; Shuper, Paul A

2012-01-01

To review and analyse in experimentally controlled studies the impact of alcohol consumption on intentions to engage in unprotected sex. To draw conclusions with respect to the question of whether alcohol has an independent effect on the incidence of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). A systematic review and meta-analysis of randomized controlled studies examined the association between blood alcohol content (BAC) and self-perceived likelihood of using a condom during intercourse. The systematic review and meta-analysis were conducted according to internationally standardized protocols (Preferred Reporting Items for Systematic Reviews and Meta-Analyses: PRISMA). The meta-analysis included an estimate of the dose-response effect, tests for publication bias and sensitivity analyses. Of the 12 studies included in the quantitative synthesis, our pooled analysis indicated that an increase in BAC of 0.1 mg/ml resulted in an increase of 5.0% (95% CI: 2.8-7.1%) in the indicated likelihood (indicated by a Likert scale) of engaging in unprotected sex. After adjusting for potential publication bias, this estimate dropped to 2.9% (95% CI: 2.0-3.9%). Thus, the larger the alcohol intake and the subsequent level of BAC, the higher the intentions to engage in unsafe sex. The main results were homogeneous, persisted in sensitivity analyses and after correction for publication bias. Alcohol use is an independent risk factor for intentions to engage in unprotected sex, and as risky sex intentions have been shown to be linked to actual risk behavior, the role of alcohol consumption in the transmission of HIV and other STIs may be of public health importance. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.

A BRIEF TARGETED REVIEW OF SUSCEPTIBILITY FACTORS, ENVIRONMENTAL EXPOSURES, ASHTMA INCIDENCE, AND RECOMMENDATIONS FOR FUTURE ASHTMA INCIDENCE RESEARCH

EPA Science Inventory

Genetics, obesity, age, and lifestyle are major susceptibility factors in the induction of asthma and can interact with environmental exposures either synergistically or antagonistically. Different environmental exposures that increase or decrease the likelihood of developing as...

The role of controllable lifestyle in the choice of specialisation among Hungarian medical doctors.

PubMed

Girasek, Edmond; Szócska, Miklós; Kovács, Eszter; Gaál, Péter

2017-11-13

Hungary has been serious facing human resources crisis in health care, as a result of a massive emigration of health workers. The resulting shortage is unevenly distributed among medical specialisations. The findings of research studies are consistent in that the most important motivating factor of the choice of the medical career and of medical specialisations is professional interest. Beyond this, it is important to examine other reasons of why students do or do not choose certain specialisations. The lifestyle determined by the chosen speciality is one such factor described in the literature. Using convenient sampling, first year resident medical doctors from each of the four Hungarian universities with a medical faculty were asked to participate in the study in 2008. In total 391 first year resident medical doctors completed the self-administered questionnaire indicating a 57.3% response rate. On the basis of the work of Schwartz et al. (Acad Med 65(3):207-210, 1990), the specialisation fields were divided into the two main categories of non-controllable (NCL) or controllable lifestyles (CL). We carried out a factor analysis on motivating factors and set up an explanatory model regarding the choice of CL and NCL specialisations. Two maximum likelihood factors were extracted from the motivational questions: "lifestyle and income" and "professional interest and consciousness". The explanatory model on specialisation choice shows that the "professional interest and consciousness" factor increases the likelihood of choosing NCL specialisations. In contrast the "lifestyle and income" factor has no significant impact on the choice of CL/NCL specialisations in the model. Our results confirm the important role of professional interest in the choice of medical specializations in Hungary. On the other hand, it seems surprising that we found no significant difference in the "lifestyle and income" related motivation among those medical residents, who opted for CL as opposed to those, who opted for NCL specialisations. This does not necessarily mean that lifestyle is not an important motivating factor, but that it is equally important for both groups of medical residents.

Simultaneous Control of Error Rates in fMRI Data Analysis

PubMed Central

Kang, Hakmook; Blume, Jeffrey; Ombao, Hernando; Badre, David

2015-01-01

The key idea of statistical hypothesis testing is to fix, and thereby control, the Type I error (false positive) rate across samples of any size. Multiple comparisons inflate the global (family-wise) Type I error rate and the traditional solution to maintaining control of the error rate is to increase the local (comparison-wise) Type II error (false negative) rates. However, in the analysis of human brain imaging data, the number of comparisons is so large that this solution breaks down: the local Type II error rate ends up being so large that scientifically meaningful analysis is precluded. Here we propose a novel solution to this problem: allow the Type I error rate to converge to zero along with the Type II error rate. It works because when the Type I error rate per comparison is very small, the accumulation (or global) Type I error rate is also small. This solution is achieved by employing the Likelihood paradigm, which uses likelihood ratios to measure the strength of evidence on a voxel-by-voxel basis. In this paper, we provide theoretical and empirical justification for a likelihood approach to the analysis of human brain imaging data. In addition, we present extensive simulations that show the likelihood approach is viable, leading to ‘cleaner’ looking brain maps and operationally superiority (lower average error rate). Finally, we include a case study on cognitive control related activation in the prefrontal cortex of the human brain. PMID:26272730

Diagnostic value of 18F-FDG-PET/CT for the evaluation of solitary pulmonary nodules: a systematic review and meta-analysis.

PubMed

Ruilong, Zong; Daohai, Xie; Li, Geng; Xiaohong, Wang; Chunjie, Wang; Lei, Tian

2017-01-01

To carry out a meta-analysis on the performance of fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (PET/CT) for the evaluation of solitary pulmonary nodules. In the meta-analysis, we performed searches of several electronic databases for relevant studies, including Google Scholar, PubMed, Cochrane Library, and several Chinese databases. The quality of all included studies was assessed by Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Two observers independently extracted data of eligible articles. For the meta-analysis, the total sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratios were pooled. A summary receiver operating characteristic curve was constructed. The I-test was performed to assess the impact of study heterogeneity on the results of the meta-analysis. Meta-regression and subgroup analysis were carried out to investigate the potential covariates that might have considerable impacts on heterogeneity. Overall, 12 studies were included in this meta-analysis, including a total of 1297 patients and 1301 pulmonary nodules. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with corresponding 95% confidence intervals (CIs) were 0.82 (95% CI, 0.76-0.87), 0.81 (95% CI, 0.66-0.90), 4.3 (95% CI, 2.3-7.9), and 0.22 (95% CI, 0.16-0.30), respectively. Significant heterogeneity was observed in sensitivity (I=81.1%) and specificity (I=89.6%). Subgroup analysis showed that the best results for sensitivity (0.90; 95% CI, 0.68-0.86) and accuracy (0.93; 95% CI, 0.90-0.95) were present in a prospective study. The results of our analysis suggest that PET/CT is a useful tool for detecting malignant pulmonary nodules qualitatively. Although current evidence showed moderate accuracy for PET/CT in differentiating malignant from benign solitary pulmonary nodules, further work needs to be carried out to improve its reliability.

Maximum Likelihood Analysis of a Two-Level Nonlinear Structural Equation Model with Fixed Covariates

ERIC Educational Resources Information Center

Lee, Sik-Yum; Song, Xin-Yuan

2005-01-01

In this article, a maximum likelihood (ML) approach for analyzing a rather general two-level structural equation model is developed for hierarchically structured data that are very common in educational and/or behavioral research. The proposed two-level model can accommodate nonlinear causal relations among latent variables as well as effects…

Detecting Growth Shape Misspecifications in Latent Growth Models: An Evaluation of Fit Indexes

ERIC Educational Resources Information Center

Leite, Walter L.; Stapleton, Laura M.

2011-01-01

In this study, the authors compared the likelihood ratio test and fit indexes for detection of misspecifications of growth shape in latent growth models through a simulation study and a graphical analysis. They found that the likelihood ratio test, MFI, and root mean square error of approximation performed best for detecting model misspecification…

Computing Maximum Likelihood Estimates of Loglinear Models from Marginal Sums with Special Attention to Loglinear Item Response Theory.

ERIC Educational Resources Information Center

Kelderman, Henk

1992-01-01

Describes algorithms used in the computer program LOGIMO for obtaining maximum likelihood estimates of the parameters in loglinear models. These algorithms are also useful for the analysis of loglinear item-response theory models. Presents modified versions of the iterative proportional fitting and Newton-Raphson algorithms. Simulated data…

Likelihood of Suicidality at Varying Levels of Depression Severity: A Re-Analysis of NESARC Data

ERIC Educational Resources Information Center

Uebelacker, Lisa A.; Strong, David; Weinstock, Lauren M.; Miller, Ivan W.

2010-01-01

Although it is clear that increasing depression severity is associated with more risk for suicidality, less is known about at what levels of depression severity the risk for different suicide symptoms increases. We used item response theory to estimate the likelihood of endorsing suicide symptoms across levels of depression severity in an…

Is Immigrant Status Relevant in School Violence Research? An Analysis with Latino Students

ERIC Educational Resources Information Center

Peguero, Anthony A.

2008-01-01

Background: The role of race and ethnicity is consistently found to be linked to the likelihood of students experiencing school violence-related outcomes; however, the findings are not always consistent. The variation of likelihood, as well as the type, of student-related school violence outcome among the Latino student population may be…

Design of simplified maximum-likelihood receivers for multiuser CPM systems.

PubMed

Bing, Li; Bai, Baoming

2014-01-01

A class of simplified maximum-likelihood receivers designed for continuous phase modulation based multiuser systems is proposed. The presented receiver is built upon a front end employing mismatched filters and a maximum-likelihood detector defined in a low-dimensional signal space. The performance of the proposed receivers is analyzed and compared to some existing receivers. Some schemes are designed to implement the proposed receivers and to reveal the roles of different system parameters. Analysis and numerical results show that the proposed receivers can approach the optimum multiuser receivers with significantly (even exponentially in some cases) reduced complexity and marginal performance degradation.

Assessment of Genetic and Nongenetic Interactions for the Prediction of Depressive Symptomatology: An Analysis of the Wisconsin Longitudinal Study Using Machine Learning Algorithms

PubMed Central

Roetker, Nicholas S.; Yonker, James A.; Chang, Vicky; Roan, Carol L.; Herd, Pamela; Hauser, Taissa S.; Hauser, Robert M.

2013-01-01

Objectives. We examined depression within a multidimensional framework consisting of genetic, environmental, and sociobehavioral factors and, using machine learning algorithms, explored interactions among these factors that might better explain the etiology of depressive symptoms. Methods. We measured current depressive symptoms using the Center for Epidemiologic Studies Depression Scale (n = 6378 participants in the Wisconsin Longitudinal Study). Genetic factors were 78 single nucleotide polymorphisms (SNPs); environmental factors—13 stressful life events (SLEs), plus a composite proportion of SLEs index; and sociobehavioral factors—18 personality, intelligence, and other health or behavioral measures. We performed traditional SNP associations via logistic regression likelihood ratio testing and explored interactions with support vector machines and Bayesian networks. Results. After correction for multiple testing, we found no significant single genotypic associations with depressive symptoms. Machine learning algorithms showed no evidence of interactions. Naïve Bayes produced the best models in both subsets and included only environmental and sociobehavioral factors. Conclusions. We found no single or interactive associations with genetic factors and depressive symptoms. Various environmental and sociobehavioral factors were more predictive of depressive symptoms, yet their impacts were independent of one another. A genome-wide analysis of genetic alterations using machine learning methodologies will provide a framework for identifying genetic–environmental–sociobehavioral interactions in depressive symptoms. PMID:23927508

Consistency in adult reporting of adverse childhood experiences.

PubMed

Colman, I; Kingsbury, M; Garad, Y; Zeng, Y; Naicker, K; Patten, S; Jones, P B; Wild, T C; Thompson, A H

2016-02-01

Many studies have used retrospective reports to assess the long-term consequences of early life stress. However, current individual characteristics and experiences may bias the recall of these reports. In particular, depressed mood may increase the likelihood of recall of negative experiences. The aim of the study was to assess whether specific factors are associated with consistency in the reporting of childhood adverse experiences. The sample comprised 7466 adults from Canada's National Population Health Survey who had reported on seven childhood adverse experiences in 1994/1995 and 2006/2007. Logistic regression was used to explore differences between those who consistently reported adverse experiences and those whose reports were inconsistent. Among those retrospectively reporting on childhood traumatic experiences in 1994/1995 and 2006/2007, 39% were inconsistent in their reports of these experiences. The development of depression, increasing levels of psychological distress, as well as increasing work and chronic stress were associated with an increasing likelihood of reporting a childhood adverse experience in 2006/2007 that had not been previously reported. Increases in mastery were associated with reduced likelihood of new reporting of a childhood adverse experience in 2006/2007. The development of depression and increases in chronic stress and psychological distress were also associated with reduced likelihood of 'forgetting' a previously reported event. Concurrent mental health factors may influence the reporting of traumatic childhood experiences. Studies that use retrospective reporting to estimate associations between childhood adversity and adult outcomes associated with mental health may be biased.

Demand and supply factors affecting the rising overmedicalization of birth in India.

PubMed

Leone, Tiziana

2014-11-01

To understand the interaction between health systems and individual factors in determining the probability of a cesarean delivery in India. In a retrospective study, data from the 2007-2008 District Level Household and Facility Survey was used to determine the risk of cesarean delivery in six states (Punjab, Delhi, Maharashtra, Andhra Pradesh, Kerala, and Tamil Nadu). Multilevel modeling was used to account for district and community effects. After controlling for key risk factors, the analysis showed that cesareans were more likely at private than public institutions (P<0.001). In terms of demand, higher education levels rather than wealth seemed to increase the likelihood of a cesarean delivery. District-level effects were significant in almost all states (P<0.001), demonstrating the need to control for health system factors. Supply factors might contribute more to the rise in cesarean delivery than does demand. Further research is needed to understand whether the quest for increased institutional deliveries in a country with high maternal mortality might be compromised by pressures for overmedicalization. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Empirical evidence for an invariant three-factor structure of the Parental Bonding Instrument in six European countries.

PubMed

Heider, Dirk; Matschinger, Herbert; Bernert, Sebastian; Vilagut, Gemma; Martínez-Alonso, Montserrat; Dietrich, Sandra; Angermeyer, Matthias C

2005-06-30

The objective of the present study was to test the Parental Bonding Instrument's (PBI) three-factor structure (care, overprotection, and authoritarianism) found by [Cox, B.J., Enns, M.W., Clara, I.P. 2000, The Parental Bonding Instrument: confirmatory evidence for a three-factor model in a psychiatric clinical sample and in the National Comorbidity Survey, Social Psychiatry and Psychiatric Epidemiology 35 (2000) 353-357.] on an eight-item short form of the scale. A total of 8813 respondents from the six European countries participating in the ESEMeD project (Belgium, France, Germany, Italy, The Netherlands, and Spain) completed either the PBI-paternal or the PBI-maternal scale. Maximum likelihood confirmatory factor analysis was used to compare the original factor model of Cox et al. with a three-factor solution that emerged from an exploration of the structure with principal component factor analysis. When gender and age subgroups, as well as different countries, were taken into account, the accuracy of the model was confirmed. The fit indices for the new model indicated a generally better model fit than the ones for the model originally developed by Cox et al. Further efforts should be directed to the modeling of the dimension authoritarianism. The results provide the opportunity to estimate the influence of the extracted factors on mental disorders in different countries. The application of the short form of the PBI seems suitable primarily for large epidemiological studies.

Private sector tuberculosis prevention in the US: Characteristics associated with interferon-gamma release assay or tuberculin skin testing.

PubMed

Stockbridge, Erica L; Miller, Thaddeus L; Carlson, Erin K; Ho, Christine

2018-01-01

To determine whether latent tuberculosis infection risk factors are associated with an increased likelihood of latent tuberculosis infection testing in the US private healthcare sector. A national sample of medical and pharmacy claims representing services rendered January 2011 through December 2013 for 3,997,986 commercially insured individuals in the US who were 0 to 64 years of age. We used multivariable logistic regression models to determine whether TB/LTBI risk factors were associated with an increased likelihood of Interferon-Gamma Release Assay (IGRA) or Tuberculin Skin Test (TST) testing in the private sector. 4.31% (4.27-4.34%) received at least one TST/IGRA test between 2011 and 2013 while 1.69% (1.67-1.72%) received a TST/IGRA test in 2013. Clinical risk factors associated with a significantly increased likelihood of testing included HIV, immunosuppressive therapy, exposure to tuberculosis, a history of tuberculosis, diabetes, tobacco use, end stage renal disease, and alcohol use disorder. Other significant variables included gender, age, asthma, the state tuberculosis rate, population density, and percent of foreign-born persons in a county. Private sector TST/IGRA testing is not uncommon and testing varies with clinical risk indicators. Thus, the private sector can be a powerful resource in the fight against tuberculosis. Analyses of administrative data can inform how best to leverage private sector healthcare toward tuberculosis prevention activities.

Factors Associated with Salmonella Prevalence in U.S. Swine Grower-Finisher Operations, 2012.

PubMed

Bjork, Kathe E; Fields, Victoria; Garber, Lindsey P; Kopral, Christine A

2018-05-15

Nontyphoidal Salmonella is an important foodborne pathogen with diverse serotypes occurring in animal and human populations. The prevalence of the organism on swine farms has been associated with numerous risk factors, and although there are strong veterinary public health controls for preventing Salmonella from entering food, there remains interest in eradicating or controlling the organism in the preharvest environment. In this study, using data collected via the U.S. Department of Agriculture (USDA) National Animal Health Monitoring System Swine 2012 study, we describe nontyphoidal Salmonella and specific serotype prevalence on U.S. grower-finisher swine operations and investigate associations between Salmonella detection and numerous factors via multiple correspondence analysis (MCA) and regression analysis. MCA plots, complementary to univariate analyses, display relationships between covariates and Salmonella detection at the farm level. In the univariate analysis, Salmonella detection varied with feed characteristics and farm management practices, reports of diseases on farms and vaccinations administered, and administration of certain antimicrobials. Results from the univariate analysis reinforce the importance of biosecurity in managing diseases and pathogens such as Salmonella on farms. All multivariable regression models for the likelihood of Salmonella detection were strongly affected by multicollinearity among variables, and only one variable, pelleted feed preparation, remained in the final model. The study was limited by its cross-sectional nature, timelines of data collection, and reliance on operator-reported data via a convenience sample.

Determinants of Corporate Web Services Adoption: A Survey of Companies in Korea

ERIC Educational Resources Information Center

Kim, Daekil

2010-01-01

Despite the growing interest and attention from Information Technology researchers and practitioners, empirical research on factors that influence an organization's likelihood of adoption of Web Services has been limited. This study identified the factors influencing Web Services adoption from the perspective of 151 South Korean firms. The…

School-Related Factors Affecting High School Seniors' Methamphetamine Use

ERIC Educational Resources Information Center

Stanley, Jarrod M.; Lo, Celia C.

2009-01-01

Data from the 2005 Monitoring the Future survey were used to examine relationships between school-related factors and high school seniors' lifetime methamphetamine use. The study applied logistic regression techniques to evaluate effects of social bonding variables and social learning variables on likelihood of lifetime methamphetamine use. The…

The Avid Adolescent Reader Revisited: Gender Differences and Their Association with Family Factors

ERIC Educational Resources Information Center

Chen, Su-Yen; Lu, Luo

2012-01-01

As a follow-up study to a cross-sectional national study that established the linkage between gender as well as family factors and the likelihood of being Taiwanese adolescent readers, this study attempted to utilize the same data set with longitudinal data to explore whether the association between family factors and being an avid adolescent…

Importance of social and cultural factors for attitudes, disclosure and time off work for depression: findings from a seven country European study on depression in the workplace.

PubMed

Evans-Lacko, Sara; Knapp, Martin

2014-01-01

Depression is experienced by a large proportion of the workforce and associated with high costs to employers and employees. There is little research on how the social costs of depression vary by social and cultural context. This study investigates individual, workplace and societal factors associated with greater perceived discomfort regarding depression in the workplace, greater likelihood of employees taking time off of work as a result of depression and greater likelihood of disclosure of depression to one's employer. Employees and managers (n = 7,065) were recruited from seven European countries to participate in the IDEA survey. Multivariable logistic regression models were used to examine associations between individual characteristics and country contextual characteristics in relation to workplace perceptions, likelihood of taking time off work and disclosing depression to an employer. Our findings suggest that structural factors such as benefit systems and flexible working hours are important for understanding workplace perceptions and consequences for employees with depression. However, manager responses that focus on offering help to the employee with depression appear to have stronger associations with positive perceptions in the workplace, and also with openness and disclosure by employees with depression. This study highlights the importance of individual, workplace and societal factors that may be associated with how people with depression are perceived and treated in the workplace, and, hence, factors that may be associated with openness and disclosure among employees with depression. Some responses, such as flexible working hours, may be helpful but are not necessarily sufficient, and our findings also emphasise the importance of support and openness of managers in addition to flexible working hours.

Importance of Social and Cultural Factors for Attitudes, Disclosure and Time off Work for Depression: Findings from a Seven Country European Study on Depression in the Workplace

PubMed Central

Evans-Lacko, Sara; Knapp, Martin

2014-01-01

Objectives Depression is experienced by a large proportion of the workforce and associated with high costs to employers and employees. There is little research on how the social costs of depression vary by social and cultural context. This study investigates individual, workplace and societal factors associated with greater perceived discomfort regarding depression in the workplace, greater likelihood of employees taking time off of work as a result of depression and greater likelihood of disclosure of depression to one's employer. Methods Employees and managers (n = 7,065) were recruited from seven European countries to participate in the IDEA survey. Multivariable logistic regression models were used to examine associations between individual characteristics and country contextual characteristics in relation to workplace perceptions, likelihood of taking time off work and disclosing depression to an employer. Results Our findings suggest that structural factors such as benefit systems and flexible working hours are important for understanding workplace perceptions and consequences for employees with depression. However, manager responses that focus on offering help to the employee with depression appear to have stronger associations with positive perceptions in the workplace, and also with openness and disclosure by employees with depression. Conclusion This study highlights the importance of individual, workplace and societal factors that may be associated with how people with depression are perceived and treated in the workplace, and, hence, factors that may be associated with openness and disclosure among employees with depression. Some responses, such as flexible working hours, may be helpful but are not necessarily sufficient, and our findings also emphasise the importance of support and openness of managers in addition to flexible working hours. PMID:24622046

To what extent can theory account for the findings of road safety evaluation studies?

PubMed

Elvik, Rune

2004-09-01

This paper proposes a conceptual framework that can be used to assess to what extent the findings of road safety evaluation research make sense from a theoretical point of view. The effects of road safety measures are modelled as passing through two causal chains. One of these, termed the engineering effect, refers to the intended effects of a road safety measure on a set of risk factors related to accident occurrence or injury severity. The engineering effect of road safety measures is modelled in terms of nine basic risk factors, one or more of which any road safety measure needs to influence in order to have the intended effect on accidents or injuries. The other causal chain producing the effects of road safety measures is termed the behavioural effect, and refers to road user behavioural adaptations to road safety measures. The behavioural effect is related to the engineering effect, in the sense that certain properties of the engineering effect of a road safety measure influence the likelihood that behavioural adaptation will occur. The behavioural effect of a road safety measure is modelled in terms of six factors that influence the likelihood that behavioural adaptation will occur. The nine basic risk factors representing the engineering effect of a road safety measure, and the six factors influencing the likelihood of behavioural adaptation can be used as checklists in assessing whether or not the findings of road safety evaluation studies make sense from a theoretical point of view. At the current state of knowledge, a more stringent evaluation of the extent to which theory can explain the findings of road safety evaluation studies is, in most cases, not possible. Copyright 2003 Elsevier Ltd.

Predictors of workplace violence among female sex workers in Tijuana, Mexico.

PubMed

Katsulis, Yasmina; Durfee, Alesha; Lopez, Vera; Robillard, Alyssa

2015-05-01

For sex workers, differences in rates of exposure to workplace violence are likely influenced by a variety of risk factors, including where one works and under what circumstances. Economic stressors, such as housing insecurity, may also increase the likelihood of exposure. Bivariate analyses demonstrate statistically significant associations between workplace violence and selected predictor variables, including age, drug use, exchanging sex for goods, soliciting clients outdoors, and experiencing housing insecurity. Multivariate regression analysis shows that after controlling for each of these variables in one model, only soliciting clients outdoors and housing insecurity emerge as statistically significant predictors for workplace violence. © The Author(s) 2014.

Two-sample statistics for testing the equality of survival functions against improper semi-parametric accelerated failure time alternatives: an application to the analysis of a breast cancer clinical trial.

PubMed

Broët, Philippe; Tsodikov, Alexander; De Rycke, Yann; Moreau, Thierry

2004-06-01

This paper presents two-sample statistics suited for testing equality of survival functions against improper semi-parametric accelerated failure time alternatives. These tests are designed for comparing either the short- or the long-term effect of a prognostic factor, or both. These statistics are obtained as partial likelihood score statistics from a time-dependent Cox model. As a consequence, the proposed tests can be very easily implemented using widely available software. A breast cancer clinical trial is presented as an example to demonstrate the utility of the proposed tests.

An EM-based semi-parametric mixture model approach to the regression analysis of competing-risks data.

PubMed

Ng, S K; McLachlan, G J

2003-04-15

We consider a mixture model approach to the regression analysis of competing-risks data. Attention is focused on inference concerning the effects of factors on both the probability of occurrence and the hazard rate conditional on each of the failure types. These two quantities are specified in the mixture model using the logistic model and the proportional hazards model, respectively. We propose a semi-parametric mixture method to estimate the logistic and regression coefficients jointly, whereby the component-baseline hazard functions are completely unspecified. Estimation is based on maximum likelihood on the basis of the full likelihood, implemented via an expectation-conditional maximization (ECM) algorithm. Simulation studies are performed to compare the performance of the proposed semi-parametric method with a fully parametric mixture approach. The results show that when the component-baseline hazard is monotonic increasing, the semi-parametric and fully parametric mixture approaches are comparable for mildly and moderately censored samples. When the component-baseline hazard is not monotonic increasing, the semi-parametric method consistently provides less biased estimates than a fully parametric approach and is comparable in efficiency in the estimation of the parameters for all levels of censoring. The methods are illustrated using a real data set of prostate cancer patients treated with different dosages of the drug diethylstilbestrol. Copyright 2003 John Wiley & Sons, Ltd.

Improving Perinatal Regionalization for Preterm Deliveries in a Medicaid Covered Population: Initial Impact of the Arkansas ANGELS Intervention

PubMed Central

Bronstein, Janet M; Ounpraseuth, Songthip; Jonkman, Jeffrey; Lowery, Curtis L; Fletcher, David; Nugent, Richard R; Hall, Richard W

2011-01-01

Objective To examine the factors associated with delivery of preterm infants at neonatal intensive care unit (NICU) hospitals in Arkansas during the period 2001–2006, with a focus on the impact of a Medicaid supported intervention, Antenatal and Neonatal Guidelines, Education, and Learning System (ANGELS), that expanded the consulting capacity of the academic medical center's maternal fetal medicine practice. Data Sources A dataset of linked Medicaid claims and birth certificates for the time period by clustering Medicaid claims by pregnancy episode. Pregnancy episodes were linked to residential county-level demographic and medical resource characteristics. Deliveries occurring before 35 weeks gestation (n = 5,150) were used for analysis. Study Design Logistic regression analysis was used to examine time trends and individual, county, and intervention characteristics associated with delivery at hospitals with NICU, and delivery at the academic medical center. Principal Findings Perceived risk, age, education, and prenatal care characteristics of women affected the likelihood of use of the NICU. The perceived availability of local expertise was associated with a lower likelihood that preterm infants would deliver at the NICU. ANGELS did not increase the overall use of NICU, but it did shift some deliveries to the academic setting. Conclusion Perinatal regionalization is the consequence of a complex set of provider and patient decisions, and it is difficult to alter with a voluntary program. PMID:21413980

Wald Sequential Probability Ratio Test for Analysis of Orbital Conjunction Data

NASA Technical Reports Server (NTRS)

Carpenter, J. Russell; Markley, F. Landis; Gold, Dara

2013-01-01

We propose a Wald Sequential Probability Ratio Test for analysis of commonly available predictions associated with spacecraft conjunctions. Such predictions generally consist of a relative state and relative state error covariance at the time of closest approach, under the assumption that prediction errors are Gaussian. We show that under these circumstances, the likelihood ratio of the Wald test reduces to an especially simple form, involving the current best estimate of collision probability, and a similar estimate of collision probability that is based on prior assumptions about the likelihood of collision.

Meta-Milgram: An Empirical Synthesis of the Obedience Experiments

PubMed Central

Haslam, Nick; Loughnan, Steve; Perry, Gina

2014-01-01

Milgram's famous experiment contained 23 small-sample conditions that elicited striking variations in obedient responding. A synthesis of these diverse conditions could clarify the factors that influence obedience in the Milgram paradigm. We assembled data from the 21 conditions (N = 740) in which obedience involved progression to maximum voltage (overall rate 43.6%) and coded these conditions on 14 properties pertaining to the learner, the teacher, the experimenter, the learner-teacher relation, the experimenter-teacher relation, and the experimental setting. Logistic regression analysis indicated that eight factors influenced the likelihood that teachers continued to the 450 volt shock: the experimenter's directiveness, legitimacy, and consistency; group pressure on the teacher to disobey; the indirectness, proximity, and intimacy of the relation between teacher and learner; and the distance between the teacher and the experimenter. Implications are discussed. PMID:24705407

Impact of HMO penetration and other environmental factors on hospital X-inefficiency.

PubMed

Rosko, M D

2001-12-01

This study examined the impact of health maintenance organization (HMO) market penetration and other internal and external environmental factors on hospital X-inefficiency in a national sample (N = 1,966) of urban U.S. hospitals in 1997. Stochastic frontier analysis, a frontier regression technique, was used to measure X-inefficiency and estimate parameters of the correlates of X-inefficiency. Log-likelihood restriction tests were used to test a variety of assumptions about the empirical model that guided its selection. Average estimated X-inefficiency in study hospitals was 12.96 percent. Increases in managed care penetration, dependence on Medicare and Medicaid, membership in a multihospital system, and location in areas where competitive pressures and the pool of uncompensated care are greater were associated with less X-inefficiency. Not-for-profit ownership was associated with increased X-inefficiency.

The Impact of Hurricane Katrina on Students’ Behavioral Disorder: A Difference-in-Difference Analysis

PubMed Central

Tian, Xian-Liang; Guan, Xian

2015-01-01

Objective: The objective of this paper is to examine the impact of Hurricane Katrina on displaced students’ behavioral disorder. Methods: First, we determine displaced students’ likelihood of discipline infraction each year relative to non-evacuees using all K12 student records of the U.S. state of Louisiana during the period of 2000–2008. Second, we investigate the impact of hurricane on evacuee students’ in-school behavior in a difference-in-difference framework. The quasi-experimental nature of the hurricane makes this framework appropriate with the advantage that the problem of endogeneity is of least concern and the causal effect of interest can be reasonably identified. Results: Preliminary analysis demonstrates a sharp increase in displaced students’ relative likelihood of discipline infraction around 2005 when the hurricane occurred. Further, formal difference-in-difference analysis confirms the results. To be specific, post Katrina, displaced students’ relative likelihood of any discipline infraction has increased by 7.3% whereas the increase in the relative likelihood for status offense, offense against person, offense against property and serious crime is 4%, 1.5%, 3.8% and 2.1%, respectively. Conclusion: When disasters occur, as was the case with Hurricane Katrina, in addition to assistance for adult evacuees, governments, in cooperation with schools, should also provide aid and assistance to displaced children to support their mental health and in-school behavior. PMID:26006127

The Impact of Hurricane Katrina on Students' Behavioral Disorder: A Difference-in-Difference Analysis.

PubMed

Tian, Xian-Liang; Guan, Xian

2015-05-22

The objective of this paper is to examine the impact of Hurricane Katrina on displaced students' behavioral disorder. First, we determine displaced students' likelihood of discipline infraction each year relative to non-evacuees using all K12 student records of the U.S. state of Louisiana during the period of 2000-2008. Second, we investigate the impact of hurricane on evacuee students' in-school behavior in a difference-in-difference framework. The quasi-experimental nature of the hurricane makes this framework appropriate with the advantage that the problem of endogeneity is of least concern and the causal effect of interest can be reasonably identified. Preliminary analysis demonstrates a sharp increase in displaced students' relative likelihood of discipline infraction around 2005 when the hurricane occurred. Further, formal difference-in-difference analysis confirms the results. To be specific, post Katrina, displaced students' relative likelihood of any discipline infraction has increased by 7.3% whereas the increase in the relative likelihood for status offense, offense against person, offense against property and serious crime is 4%, 1.5%, 3.8% and 2.1%, respectively. When disasters occur, as was the case with Hurricane Katrina, in addition to assistance for adult evacuees, governments, in cooperation with schools, should also provide aid and assistance to displaced children to support their mental health and in-school behavior.

A comprehensive assessment of collision likelihood in Geosynchronous Earth Orbit

NASA Astrophysics Data System (ADS)

Oltrogge, D. L.; Alfano, S.; Law, C.; Cacioni, A.; Kelso, T. S.

2018-06-01

Knowing the likelihood of collision for satellites operating in Geosynchronous Earth Orbit (GEO) is of extreme importance and interest to the global community and the operators of GEO spacecraft. Yet for all of its importance, a comprehensive assessment of GEO collision likelihood is difficult to do and has never been done. In this paper, we employ six independent and diverse assessment methods to estimate GEO collision likelihood. Taken in aggregate, this comprehensive assessment offer new insights into GEO collision likelihood that are within a factor of 3.5 of each other. These results are then compared to four collision and seven encounter rate estimates previously published. Collectively, these new findings indicate that collision likelihood in GEO is as much as four orders of magnitude higher than previously published by other researchers. Results indicate that a collision is likely to occur every 4 years for one satellite out of the entire GEO active satellite population against a 1 cm RSO catalogue, and every 50 years against a 20 cm RSO catalogue. Further, previous assertions that collision relative velocities are low (i.e., <1 km/s) in GEO are disproven, with some GEO relative velocities as high as 4 km/s identified. These new findings indicate that unless operators successfully mitigate this collision risk, the GEO orbital arc is and will remain at high risk of collision, with the potential for serious follow-on collision threats from post-collision debris when a substantial GEO collision occurs.

Psychometric properties of the brief version of the Fear of Negative Evaluation Scale in a Turkish sample.

PubMed

Koydemir, Selda; Demir, Ayhan

2007-06-01

The purpose of the study was to report initial data on the psychometric properties of the Brief Fear of Negative Evaluation Scale. The scale was applied to a nonclinical sample of 250 (137 women, 113 men) Turkish undergraduate students selected randomly from Middle East Technical University. Their mean age was 20.4 yr. (SD= 1.9). The factor structure of the Turkish version, its criterion validity, and internal reliability coefficients were assessed. Although maximum likelihood factor analysis initially indicated that the scale had only one factor, a forced two-factor solution accounted for more variance (61%) in scale scores than a single factor. The straightforward items loaded on the first factor, and the reverse-coded items loaded on the second factor. The total score was significantly positively correlated with scores on the Revised Cheek and Buss Shyness Scale and significantly negatively correlated with scores on the Rosenberg Self-Esteem Scale. Factor 1 (straightforward items) correlated more highly with both Shyness and Self-esteem than Factor 2 (reverse-coded items). Internal consistency estimate was .94 for the Total scores, .91 for the Factor 1 (straightforward items), and .87 for the Factor 2 (reverse-coded items). No sex differences were evident for Fear of Negative Evaluation.

Three methods to construct predictive models using logistic regression and likelihood ratios to facilitate adjustment for pretest probability give similar results.

PubMed

Chan, Siew Foong; Deeks, Jonathan J; Macaskill, Petra; Irwig, Les

2008-01-01

To compare three predictive models based on logistic regression to estimate adjusted likelihood ratios allowing for interdependency between diagnostic variables (tests). This study was a review of the theoretical basis, assumptions, and limitations of published models; and a statistical extension of methods and application to a case study of the diagnosis of obstructive airways disease based on history and clinical examination. Albert's method includes an offset term to estimate an adjusted likelihood ratio for combinations of tests. Spiegelhalter and Knill-Jones method uses the unadjusted likelihood ratio for each test as a predictor and computes shrinkage factors to allow for interdependence. Knottnerus' method differs from the other methods because it requires sequencing of tests, which limits its application to situations where there are few tests and substantial data. Although parameter estimates differed between the models, predicted "posttest" probabilities were generally similar. Construction of predictive models using logistic regression is preferred to the independence Bayes' approach when it is important to adjust for dependency of tests errors. Methods to estimate adjusted likelihood ratios from predictive models should be considered in preference to a standard logistic regression model to facilitate ease of interpretation and application. Albert's method provides the most straightforward approach.

Math-oriented fields of study and the race gap in graduation likelihoods at elite colleges.

PubMed

Gelbgiser, Dafna; Alon, Sigal

2016-07-01

This study examines the relationship between chosen field of study and the race gap in college completion among students at elite colleges. Fields of study are characterized by varying institutional arrangements, which impact the academic performance of students in higher education. If the effect of fields on graduation likelihoods is unequal across racial groups, then this may account for part of the overall race gap in college completion. Results from a large sample of students attending elite colleges confirm that fields of study influence the graduation likelihoods of all students, above and beyond factors such as students' academic and social backgrounds. This effect, however, is asymmetrical: relative to white students, the negative effect of the institutional arrangements of math-oriented fields on graduation likelihood is greater for black students. Therefore, the race gap is larger within math-oriented fields than in other fields, which contributes to the overall race gap in graduation likelihoods at these selective colleges. These results indicate that a nontrivial share of the race gap in college completion is generated after matriculation, by the environments that students encounter in college. Consequently, policy interventions that target field of study environments can substantially mitigate racial disparities in college graduation rates. Copyright © 2016 Elsevier Inc. All rights reserved.

Maternal cigarette smoking during pregnancy and criminal/deviant behavior: a meta-analysis.

PubMed

Pratt, Travis C; McGloin, Jean Marie; Fearn, Noelle E

2006-12-01

A growing body of empirical literature has emerged examining the somewhat inconsistent relationship between maternal cigarette smoking (MCS) during pregnancy and children's subsequent antisocial behavior. To systematically assess what existing studies reveal regarding MCS as a criminogenic risk factor for offspring, the authors subjected this body of literature to a meta-analysis. The analysis reveals a statistically significant--yet rather small--overall mean "effect size" of the relationship between MCS and the likelihood children will engage in deviant/criminal behavior. In addition to being rather moderate in size, the MCS-crime/deviance relationship is sensitive to a number of methodological specifications across empirical studies--particularly those associated with sample characteristics. The implications of this modest, and somewhat unstable, relationship are discussed in terms of guidelines for future research on this subject and how existing theoretical perspectives may be integrated to explain the MCS-crime/deviance link.

Identifying Factors That Increase the Likelihood for Alcohol-Induced Blackouts in the Prepartying Context

PubMed Central

LaBrie, Joseph W.; Hummer, Justin; Kenney, Shannon; Lac, Andrew; Pedersen, Eric

2015-01-01

The present study examined risk factors related to “blacking out” (e.g., temporary periods of memory loss during drinking) during preparty drinking events (i.e., pregaming, predrinking). Participants were students from two universities on the West Coast who reported past month prepartying (N = 2,546) in online surveys administered in the fall of 2008. Among these students, 25% (n = 636) reported blacking out during at least one occasion in which they prepartied in the past month. A logistic regression model underscored that Greek student affiliation, family history of alcohol abuse, frequency of prepartying, and both playing drinking games and consuming shots of liquor while prepartying increased the likelihood of blacking out. Limitations and implications for future research and collegiate prevention strategies are discussed. PMID:21222521

Updated logistic regression equations for the calculation of post-fire debris-flow likelihood in the western United States

USGS Publications Warehouse

Staley, Dennis M.; Negri, Jacquelyn A.; Kean, Jason W.; Laber, Jayme L.; Tillery, Anne C.; Youberg, Ann M.

2016-06-30

Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can generate dangerous flash floods and debris flows. To reduce public exposure to hazard, the U.S. Geological Survey produces post-fire debris-flow hazard assessments for select fires in the western United States. We use publicly available geospatial data describing basin morphology, burn severity, soil properties, and rainfall characteristics to estimate the statistical likelihood that debris flows will occur in response to a storm of a given rainfall intensity. Using an empirical database and refined geospatial analysis methods, we defined new equations for the prediction of debris-flow likelihood using logistic regression methods. We showed that the new logistic regression model outperformed previous models used to predict debris-flow likelihood.

The effects of gender, family status, and race on sentencing decisions.

PubMed

Freiburger, Tina L

2010-01-01

This study sought to determine the effects of family role, gender, and race on judges' sentencing decisions. To assess these effects, factorial surveys were sent to 360 Court of Common Plea judges who presided over criminal court cases in the state. Survey administration resulted in a 51% response rate. The findings indicate that defendants who were depicted as performing caretaker roles had a significantly decreased likelihood of incarceration. Further analysis found that the reduction in likelihood of incarceration for being a caretaker was larger for males than for females. Examination of the interaction of familial role with race found that familial role equally reduced the likelihood of incarceration for black and white females. Familial responsibility, however, resulted in a significantly greater decrease in likelihood of incarceration for black men than for white men. 2009 John Wiley & Sons, Ltd.

Study of Individualization and Bias in Nursing Home Fall Prevention Practices.

PubMed

Colón-Emeric, Cathleen S; Corazzini, Kirsten; McConnell, Eleanor; Pan, Wei; Toles, Mark; Hall, Rasheeda; Batchelor-Murphy, Melissa; Yap, Tracey L; Anderson, Amber L; Burd, Andrew; Anderson, Ruth A

2017-04-01

Little is known about how nursing home staff use resident characteristics to individualize care delivery or whether care is affected by implicit bias. Randomized factorial clinical vignette survey. Sixteen nursing homes in North Carolina. Nursing, rehabilitation, and social services staff (n = 433). Vignettes describing hypothetical residents were generated from a matrix of clinical and demographic characteristics. Resident age, race and gender were suggested by a photo. Participants completed up to four randomly assigned vignettes (n = 1615), rating the likelihood that 12 fall prevention activities would be used for the resident. Fixed and random effects mixed model analysis examined the impact of vignette resident characteristics and staff characteristics on four intervention categories. Staff reported a higher likelihood of fall prevention activities in all four categories for residents with a prior fall (0.2-0.5 points higher, 10 point scale, P < 0.05), but other risk factors did not affect scores. There was little evidence of individualization; only dementia increased the reported likelihood of environmental modification (0.3, P < 0.001, 95% CI 0.2-0.5). Individualization did not vary with staff licensure category or clinical experience. Registered nurses consistently reported higher likelihoods of all fall prevention activities than did licensed practical nurses, unlicensed staff and other professional staff (1.0-2.7 points, P < 0.001 to 0.005). There was a small degree of implicit racial bias; staff indicated that environmental modification would be less likely to occur in otherwise identical vignettes including a photo of a black rather than a white resident (-0.2 points, 95% CI -0.3 to -0.1). Nursing home staff report a standardized approach to fall prevention without individualization. We found a small impact from implicit racial bias that should be further explored. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Papillary Thyroid Microcarcinomas: Big Decisions for a Small Tumor

PubMed Central

Haymart, Megan Rist; Cayo, Max; Chen, Herbert

2016-01-01

Background The clinical significance of papillary thyroid microcarcinoma (PTMC) is debated, and therefore the rise in incidence of PTMC creates management dilemmas. The following study evaluates factors influencing decisions to treat. Materials and Methods Between 1994 and 2007, 1361 patients underwent thyroid surgery at a single institution. Of these patients, 107 were diagnosed with PTMC. The type of surgical intervention, likelihood of referral to an endocrinologist, use of radioactive iodine, and administration of suppressive doses of levothyroxine (LT4) were analyzed in relation to patient and tumor characteristics. Results Multifocality and larger size were predictive of which patients underwent total thyroidectomy on multivariable logistic regression (P = .004 and P = .001, respectively). Larger mean tumor size, 0.62 ± 0.004 versus 0.34 ± 0.006 cm, was independently associated with increased likelihood of endocrine referral (P = .029). Multifocality, diagnosis via FNA preoperatively, larger mean size of PTMC, and endocrine referral were independently associated with increased likelihood of receiving radioactive iodine (RAI). On multivariable analysis, only total thyroidectomy and endocrine referral were independently associated with treatment with suppressive doses of LT4 (P = .001 and .001, respectively). In the 47 patients with unifocal PTMC <0.8 cm diameter, the mean size of tumor focus was larger in the subgroup undergoing total thyroidectomy (P = .004). Surprisingly, in these very low risk PTMC patients, the likelihood of RAI for remnant ablation was independently associated with younger patient age (P = .029). In the subgroup with unifocal <0.8 cm disease, the mean age of patients receiving RAI was 34 ± 3.3 years versus 48 ± 2.3 years in those not receiving RAI (P = .003). Conclusions The decision tree in the management of PTMC is beginning at the time of surgery, and referral to endocrinology is associated with a more aggressive course. Younger age is predictive of RAI administration in the lowest-risk PTMC patients. PMID:19653044