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871.
Two statistical applications for estimation and prediction of flows in traffic networks are presented. In the first, the number of route users are assumed to be independent α-shifted gamma Γ(θ, λ0) random variables denoted H(α, θ, λ0), with common λ0. As a consequence, the link, OD (origin-destination) and node flows are also H(α, θ, λ0) variables. We assume that the main source of information is plate scanning, which permits us to identify, totally or partially, the vehicle route, OD and link flows by scanning their corresponding plate numbers at an adequately selected subset of links. A Bayesian approach using conjugate families is proposed that allows us to estimate different traffic flows. In the second application, a stochastic demand dynamic traffic model to predict some traffic variables and their time evolution in real networks is presented. The Bayesian network model considers that the variables are generalized Beta variables such that when marginally transformed to standard normal become multivariate normal. The model is able to provide a point estimate, a confidence interval or the density of the variable being predicted. Finally, the models are illustrated by their application to the Nguyen Dupuis network and the Vermont-State example. The resulting traffic predictions seem to be promising for real traffic networks and can be done in real time.  相似文献   
872.
Autocorrelation in errors and multicollinearity among the regressors are serious problems in regression analysis. The aim of this paper is to examine multicollinearity and autocorrelation problems concurrently and to compare the r ? k class estimator to the generalized least squares estimator, the principal components regression estimator and the ridge regression estimator by the scalar and matrix mean square error criteria in the linear regression model with correlated errors.  相似文献   
873.
We consider a linguistically diversified society and examine the notion of language disenfranchisement when some individuals are denied the full access to documents and political process in their native tongues. To calculate the disenfranchisement indices we use the Dyen percentage cognate matrix of linguistic distances between Indo‐European languages and apply survey and population data on language proficiency in the European Union. We then determine optimal sets of official languages that depend on society's sensitivity against disenfranchisement and comprehensiveness of the chosen language regime. We also discuss the language situation in the European Union after its last enlargement. (JEL: D70, O52, Z13)  相似文献   
874.
Ethical leadership: A review and future directions   总被引:9,自引:0,他引:9  
Our literature review focuses on the emerging construct of ethical leadership and compares this construct with related concepts that share a common concern for a moral dimension of leadership (e.g., spiritual, authentic, and transformational leadership). Drawing broadly from the intersection of the ethics and leadership literatures, we offer propositions about the antecedents and outcomes of ethical leadership. We also identify issues and questions to be addressed in the future and discuss their implications for research and practice. Our review indicates that ethical leadership remains largely unexplored, offering researchers opportunities for new discoveries and leaders opportunities to improve their effectiveness.  相似文献   
875.
Using a sample of Spanish Catholics, we examined the level of religiosity (measured by beliefs, prayer and church attendance) and the relationship between religiosity and various socio-economic variables. An Ordered Logit estimation of religiosity equations showed that: women are more religious than men; religious activity increases with age; there is a (marginally) significant positive relationship between schooling and religiosity; religiosity is positively related to exposure to religious activity during childhood; and male religious activity is positively affected by marital status (being married to a Catholic wife) and by the number of children at home. The results also demonstrate the importance of the "salvation motive" for the two genders and the presence of the "professional utilitarian motive" in male religious behavior.  相似文献   
876.
Pathological gambling (PG) is an impulse control disorder and a model behavioral addiction. Familial factors have been observed in clinical studies of pathological gamblers, and twin studies have demonstrated a genetic influence contributing to the development of PG. Serotonergic, noradrenergic, and dopaminergic dysfunction have been reported as biological factors contributing to the pathophysiology of PG. Molecular genetic techniques have been used to investigate the role of genetic factors in PG. Molecular genetic research has identified specific allele variants of candidate genes corresponding to these neurotransmitter systems to be associated with PG. Associations have been reported between pathological gamblers and allele variants of polymorphisms at dopamine receptor genes, the serotonin transporter gene, and the monoamine-oxidase A gene. Although preliminary data suggest that some of these differences are gender-specific, more research needs to be performed to substantiate gender-specific genetic contributions to the development of pathological gambling. The review of the current findings on genetics of PG suggests that liability to PG is in part mediated by genetic factors. Additional studies are needed to replicate and extend these findings, as well as to better understand the influence of specific allelic variants to differences in biological and behavioral functioning.  相似文献   
877.
878.
The purpose of this article is to conduct a social-psychological analysis of C. Wright Mills and his “Hispanic writings.” I demonstrate how Mills's social-psychological theoretical framework, as articulated in Character and Social Structure, is attendant in his comments on Latinos and Latin America—a population and geopolitical region for which he seemed to have a compelling if somewhat distant fascination. I conclude with a synopsis and appraisal of: (1) Mills's personal perceptions of Latinos; (2) the social structural factors that impacted on the four Latino groups, and (3) the personality traits of Latinos as Mills saw them.  相似文献   
879.
This replication of a previous analysis of the effect of sociological variables on infant mortality rates in Chile refines the earlier work by using the more numerous communes for comparisons, by presenting the basic data in the form of a path analysis, and by expanding the theory to include “health practices,” customs, such as avoiding teenage pregnancies, that are community-backed and maintained. This type of practice is then integrated into the “institutionalized problem-solving capacity” framework that guides the analysis. Urabnization and voting, the two indicators of institutionalized problem-solving capacity, predict reduced infant morality, as before. Teen pregnancies is a positive predictor, as expected, but the number of children already born does not predict. These results are net of two indicators of health technology-whether or not a physician was in attendance, and the number of clinics. Mother's education also predicted low infant morality, and the theory is applied to this well-known predictor to interpret its effect. In addition, the anomalous role of mother's education in the dominant biomedical explanation is highlighted.  相似文献   
880.
This study aimed to ascertain by means of a new scale older adults' motives for engaging in physical activity, in a probability and representative sample of an older urban population. The sample size was 630 older adults, ranging from 65 to 94 years in age, randomly selected using multistage sampling. The participants completed a 17-item questionnaire, as well as answering questions on demographic variables, type of demand for physical activity, and physician's recommendation. A principal-component analysis was performed. The relationships among the four factors (physical health, social relationships, competence, and physician's advice) show a clearly motivational structure. Significant relationships have also been found between physician's recommendation and type of demand. The findings suggest that programs promoting physical activity in older adults should have different characteristics from those aimed at general adult populations.  相似文献   
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