This study determined the shape of trajectories from ages 13 to 19 of 4 types of dating abuse perpetration and examined whether the demographic characteristics of sex, minority status, socioeconomic status, and family structure systematically explained variation in the trajectories. The data are from 5 waves of data collected from 973 adolescents participating in the control group of a randomized trial. The mean trajectory for psychological dating abuse was positive linear, but the mean trajectories were curvilinear for moderate physical, severe physical, and sexual dating abuse. At all ages, boys reported more severe physical and sexual dating abuse than girls, minorities reported more moderate and severe physical dating abuse than Whites, adolescents in single‐parent households reported more psychological and severe physical dating abuse than those in 2‐parent‐households, and parental education was negatively associated with psychological and moderate physical dating abuse perpetration. The findings have implications for future research and for practice. 相似文献
The tail Yt = Xt – u of a random sequence {Xt ∈ , t ∈ } with identically distributed Xt is approximated by the generalized Pareto distribution according to the extreme value theory, wherein Yt occurs in clusters because of the dependence in the random sequence. Nevertheless, the parameters of the generalized Pareto distribution are estimated by the same methods as in the case of independent and identically distributed Yt, provided that there is independence between the clusters of Yt. The estimation variances and confidence intervals can be estimated by the jackknife method. The approaches are theoretically discussed and verified by extensive numerical researches. 相似文献
The Net Ecosystem Exchange describes the net carbon dioxide flux between an ecosystem and the atmosphere and is a key quantity in climate change studies and in political negotiations. This paper provides a spatio-temporal statistical framework, which is able to infer the Net Ecosystem Exchange from remotely-sensed carbon dioxide ground concentrations together with data on the Normalized Difference Vegetation Index, the Gross Primary Production and the land cover classification. The model is based on spatial and temporal latent random effects, that act as space–time varying coefficients, which allows for a flexible modeling of the spatio-temporal auto- and cross-correlation structure. The intra- and inter-annual variations of the Net Ecosystem Exchange are evaluated and dynamic maps are provided on a nearly global grid and in intervals of 16 days. 相似文献
The interactions between the processes of urbanization and international migration in less developed and transition countries have important repercussions for socioeconomic development, but are not well understood. Based on the retrospective data from the Albanian Living Standards Measurement Survey 2008, we first assess the geography of migration in terms of the rural–urban continuum, the urban hierarchy and the outside world since 1990. We then investigate the spatio-temporal diffusion of rural-to-urban and international movements using survival models. Results reveal an immediate onset of large-scale rural exodus, despite the post-communist crisis. Internal migrants mainly moved to the capital, bypassing secondary cities, and were predominantly female. Initially, international migrants were primarily men who tended to originate from the main urban agglomerations. The diffusion of opportunities to emigrate down the urban hierarchy and across the sexes then redirected the rural exodus abroad, despite domestic economic development. This evolution in population mobility is related to the gendered patterns and interlinkages of the two flows, as well as to rising inequalities within the urban hierarchy.
Internationally adopted (IA) children are at increased risk for health-related, developmental, and behavioral difficulties.
This article reviews the literature on various interventions currently used with IA populations; including health-related
interventions provided by medical specialists, preparation programs provided by adoption agencies and other social service
organizations, treatments for attachment and behavioral disorders, psychoeducational services, programs designed to improve
children’s care prior to adoption, and parent-based initiatives. Surprisingly, very little systematic information exists regarding
the effectiveness of interventions designed to prevent and remediate these difficulties in IA children. Recommendations for
future research activity and for best practice approaches to intervention are discussed. 相似文献
This paper proposes novel tests for the absence of jumps in a univariate semimartingale and for the absence of common jumps in a bivariate semimartingale. Our methods rely on ratio statistics of power variations based on irregular observations, sampled at different frequencies. We develop central limit theorems for the statistics under the respective null hypotheses and apply bootstrap procedures to assess the limiting distributions. Furthermore, we define corrected statistics to improve the finite sample performance. Simulations show that the test based on our corrected statistic yields good results and even outperforms existing tests in the case of regular observations. 相似文献