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Clinical surveillance was the only way to detect bovine spongiform encephalopathy (BSE) until July 2000 in France. From the 103 cases identified as such between 1991 and June 2000, we used a back-calculation method to reconstruct the longitudinal trend of BSE infections. Between July 1987 and June 1997, an estimated 51,300 (CI =[24,300-84,700]) cattle were infected in France. The comprehensive surveillance of BSE with rapid tests, set up in France since 2001 at the abattoir and fallen plant, allowed study of the relative exposure of the successive birth cohorts with nonconditional logistic regression models adjusted for possible confounding variables. The results were in agreement with those of the back-calculation model, estimating a decrease of the BSE exposure from the birth cohort July 1995-June 1996 that matched with the decrease of the infection after June 1996. In view of the long incubation period of BSE, it is not possible to precisely assess the impact of any control measure before several years. Modeling was therefore used to estimate prospectively the efficiency of the ban of meat and bone meal extended to all farm species in November 2000. Using parameters about age at infection and incubation time estimated earlier, we assessed the minimum time to first detection if infections still occurred. We have waited up to June 2007 to know if less than 100 infections occurred among French cattle during the 6 months following January 2001. 相似文献
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A Foreigner Who Does Not Steal My Job: The Role of Unemployment Risk and Values in Attitudes toward Equal Opportunities 下载免费PDF全文
Immigration has become systematically politicized and opposed by many individuals. We examine individual attitudes toward equal opportunities for foreigners and Swiss citizens, using cross‐sectional data from the Swiss Household Panel. Individuals with low levels of education tend to oppose foreigners, while the opposition by individuals with high levels of education increases with the risk of unemployment. Values and beliefs explain the negative attitudes of individuals with low levels of education, but not the association with the risk of unemployment for individuals with high levels of education. Clearly, both values and economic factors are important for explaining attitudes toward foreigners. 相似文献
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Didier Chabanet 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2017,28(6):2360-2382
Employee commitment to an organization is accepted as an important concept in organization psychology. Yet commitment to a project on which an employee might be working is largely unknown. Additional complications arise when the project makes use of volunteers who donate their time for reasons other than pecuniary reward. The relationships between volunteers, organizations, and projects represent a gap in the field of organizational commitment knowledge. This paper identifies from literature the values that inform and influence volunteer commitment levels. Known antecedents of commitment are developed to present a model which encapsulates the variables that should be recognized as influencing volunteer commitment levels within a project context. The paper proposes a conceptual model of volunteer commitment to a project using three categories of commitment: emotional, purposeful and contextual, and concludes that the next phase of the study will test this model and develop a tool that will enable the measurement of volunteer commitment in a project context. 相似文献
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Modelling time-varying and frequency-specific relationships between two brain signals is becoming an essential methodological tool to answer theoretical questions in experimental neuroscience. In this article, we propose to estimate a frequency Granger causality statistic that may vary in time in order to evaluate the functional connections between two brain regions during a task. We use for that purpose an adaptive Kalman filter type of estimator of a linear Gaussian vector autoregressive model with coefficients evolving over time. The estimation procedure is achieved through variational Bayesian approximation and is extended for multiple trials. This Bayesian State Space (BSS) model provides a dynamical Granger-causality statistic that is quite natural. We propose to extend the BSS model to include the à trous Haar decomposition. This wavelet-based forecasting method is based on a multiscale resolution decomposition of the signal using the redundant à trous wavelet transform and allows us to capture short- and long-range dependencies between signals. Equally importantly it allows us to derive the desired dynamical and frequency-specific Granger-causality statistic. The application of these models to intracranial local field potential data recorded during a psychological experimental task shows the complex frequency-based cross-talk between amygdala and medial orbito-frontal cortex. 相似文献
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Etienne B. Roesch Lucas Tamarit Lionel Reveret Didier Grandjean David Sander Klaus R. Scherer 《Journal of Nonverbal Behavior》2011,35(1):1-16
To investigate the perception of emotional facial expressions, researchers rely on shared sets of photos or videos, most often
generated by actor portrayals. The drawback of such standardized material is a lack of flexibility and controllability, as
it does not allow the systematic parametric manipulation of specific features of facial expressions on the one hand, and of
more general properties of the facial identity (age, ethnicity, gender) on the other. To remedy this problem, we developed
FACSGen: a novel tool that allows the creation of realistic synthetic 3D facial stimuli, both static and dynamic, based on
the Facial Action Coding System. FACSGen provides researchers with total control over facial action units, and corresponding
informational cues in 3D synthetic faces. We present four studies validating both the software and the general methodology
of systematically generating controlled facial expression patterns for stimulus presentation. 相似文献
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Didier Renard Helena Geys Geert Molenberghs Tomasz Burzykowski Marc Buyse Tony Vangeneugden Luc Bijnens 《Journal of applied statistics》2003,30(2):235-247
The objective of this paper is to extend the surrogate endpoint validation methodology proposed by Buyse et al. (2000) to the case of a longitudinally measured surrogate marker when the endpoint of interest is time to some key clinical event. A joint model for longitudinal and event time data is required. To this end, the model formulation of Henderson et al. (2000) is adopted. The methodology is applied to a set of two randomized clinical trials in advanced prostate cancer to evaluate the usefulness of prostate-specific antigen (PSA) level as a surrogate for survival. 相似文献
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Magali Dufour Noël Nguyen Karine Bertrand Michel Perreault Didier Jutras-Aswad Adèle Morvannou Julie Bruneau Djamal Berbiche Élise Roy 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2016,32(3):1039-1053
Cocaine use is highly prevalent and a major public health problem. While some studies have reported frequent comorbidity problems among cocaine users, few studies have included evaluation of gambling problems. This study aimed to estimate the prevalence of gambling problems and compare those who were at-risk gamblers with non-problem gamblers in terms of mental health problems, substance use problems, and some risk factors (i.e. family antecedents, erroneous perceptions and coping strategies) among individuals who smoke or inject cocaine. A total of 424 smoked or injected cocaine users recruited through community-based programs in Montreal (Quebec) completed the questionnaire, including the Canadian Pathological Gambling Index, the Composite International Diagnostic Interview, the CAGE, and the Severity Dependence Scale. Of the sample, 18.4 % were considered at-risk gamblers, of whom 7.8 % had problems gambling and 10.6 % were moderate-risk gamblers. The at-risk group was more likely to have experienced a recent phobic disorder and alcohol problems than the non-problem group. A multivariate analysis showed that, compared to those who were non-problem gamblers, the at-risk ones were more likely to have lost a large sum of money when they first started gambling, believed that their luck would turn, and gambled in reaction to painful life events. These results indicate the need to include routines for screening to identify gambling problem among cocaine users. 相似文献
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Didier Blanchet 《Journal of population economics》1989,1(3):183-194
This paper reexamines the problem of the relationship between demographic growth and per capita income in neo-classical growth models with age-structured populations. It is suggested that, when they assume a constant rate of capital depreciation, such models overestimate the negative impact of population growth through capital dilution effects. With more realistic depreciation schedules, the ageing of the capital stock which results from lower growth implies a higher overall depreciation rate, which reduces benefits from lower capital dilution. The implications of this observation are examined for the existence of an optimum population growth rate, for models with heterogeneous capital, and for models where capital obsolescence is not fixed but is allowed to vary.This article is a modified version of a paper presented at the First Annual Meeting of the European Society for Population Economics, Rotterdam, September 1987. I am indebted to the anonymous referees for helpful comments and suggestions and to Linda Sergent for revising the English text. 相似文献
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