Sample size estimation for comparing rates of change in K-group repeated count outcomes

Sample size estimation for comparing the rates of change in two-arm repeated measurements has been investigated by many investigators. In contrast, the literature has paid relatively less attention to sample size estimation for studies with multi-arm repeated measurements where the design and data analysis can be more complex than two-arm trials. For continuous outcomes, Jung and Ahn (2004 Jung, S., Ahn, C. (2004). K-sample test and sample size calculation for comparing slopes in data with repeated measurements. Biometrical J. 46(5):554–564.[Crossref], [Web of Science ®] , [Google Scholar]) and Zhang and Ahn (2013 Zhang, S., Ahn, C. (2013). Sample size calculation for comparing time-averaged responses in k-group repeated measurement studies. Comput. Stat. Data Anal. 58:283–291.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) have presented sample size formulas to compare the rates of change and time-averaged responses in multi-arm trials, using the generalized estimating equation (GEE) approach. To our knowledge, there has been no corresponding development for multi-arm trials with count outcomes. We present a sample size formula for comparing the rates of change in multi-arm repeated count outcomes using the GEE approach that accommodates various correlation structures, missing data patterns, and unbalanced designs. We conduct simulation studies to assess the performance of the proposed sample size formula under a wide range of designing configurations. Simulation results suggest that empirical type I error and power are maintained close to their nominal levels. The proposed method is illustrated using an epileptic clinical trial example.     

深度老龄化对我国劳动就业的潜在影响

对我国就业人口现状,2000-2010年城市、城镇、乡村人口就业速度,我国三大产业就业人口变化及人口年龄组劳动参与率变化的研究表明:若退休年龄不变,2030年我国潜在劳动力将比2010年减少14%;若男女退休年龄分别推迟5年,则2030年潜在劳动力仍将与2010年相当。然而,青年劳动力的比例下降快,农村尤其明显;2020年以后我国劳动力递减速度快,2040年我国60岁以上、65岁以上和80岁以上老年人口比例将超过28%、22%和4%。近20年我国经济发展很快,但面临老龄化的严重挑战,老龄化通过劳动力老化、社会保障、生产成本、商品出口、社会消费、货币汇率等途径,对经济持久地产生影响。     

Migrant women’s economic success in Russia: objective reality and subjective assessment

This study contributes to the growing body of literature on the outcomes of labour migration by focusing on the effects of migrant legal status on the economic and perceptual measures of migration success. To study the effects of legal status, we use a sample of Central Asian migrant women who work in Russia and of their native counterparts who occupy the same positions on the labour market. Similar to the studies in the developed settings, we find that a temporary legal status is associated with an earnings penalty and that permanent legal status corrects this earning disparity. We also find that both temporary and permanent migrant status is positively associated with perceptions of pay inequality but that, irrespective of these perceptions, both types of migrants are more likely to be satisfied with their jobs than natives. We interpret these findings within the legal and social context of migrant economic incorporation in Russia and relate them to the findings from other migrant-receiving settings.     

Divorce and the Divine: The Role of Spirituality in Adjustment to Divorce

This study examined the role of three spiritual responses to divorce for psychological adjustment: appraising the event as a sacred loss/desecration, engaging in adaptive spiritual coping, and experiencing spiritual struggles. A sample of 100 adults (55% female) was recruited through public divorce records. Most appraised their divorce as a sacred loss/desecration (74%), experienced spiritual struggles (78%), and engaged in adaptive spiritual coping (88%). Appraisals of sacred loss/desecration and spiritual struggles were tied to higher levels of depression. Adaptive spiritual coping was tied to greater posttraumatic growth. Spiritual coping and struggles each contributed uniquely to adjustment beyond parallel forms of nonspiritual coping and struggles and mediated links between viewing the divorce as a sacred loss/desecration and depression.     

Fathering With Multiple Partners: Links to Children's Well‐Being in Early Childhood

The claim that multiple partner fertility may pose a risk of adverse outcomes for children has not been tested. We test this argument using a sample of 4,027 resident fathers and children from the Fragile Families and Child Well‐being Survey by examining the pathways through which fathers' multipartnered fertility is associated with children's externalizing behaviors and physical health status at 36 months. Path analyses indicate that multiple partner fertility exerted both a significant direct and indirect effect through paternal depression to influence children's externalizing behaviors. Fathers' multiple partner fertility also exerted a significant indirect effect through one mediator—father involvement—to influence children's physical health. This evidence suggests that the disruptions brought about by multipartnered fertility are important for understanding child well‐being.     

通辽市近45年农业水资源变化分析

分析了通辽市近４５ 年降水、潜在蒸散及农田水分盈亏的变化,结果表明：年降水量在周期变化中具有减小的趋势,年降水量的稳定性增加,潜在蒸散波动上升。本世纪６０ 年代以来,春旱有所缓减,秋旱有所加剧     

Positive Consequences of Parental Divorce Among Israeli Young Adults

Abstract

Within the framework of cognitive theories that define crisis as a challenge to self-development, this study explored the positive long-term outcomes of coping with parental divorce in young adults. Data were collected from self-reports of 158 Israeli young adults whose parents divorced when they were adolescents. Together with painful feelings, almost half the participants reported “more positive than negative outcomes” and less than a quarter thought that the divorce had “more negative than positive outcomes.” The various positive outcomes were found to form three constructs reflecting maturity and growth: empowerment, empathy, and relationship-savvy. Coping styles used by the participants proved strongly connected to long-term outcomes. Reciprocal support was the main coping style used by the young adults and their significant others, and was connected to positive long-term outcomes. Based on multiple regression analyses, the study proposes a sequential model that charts a developmental sequence that enhances long-term positive outcomes. These and other results are discussed within the framework of posttraumatic growth perspective.     

Central Limit Theorem approximations for the number of runs in Markov-dependent binary sequences

We consider Markov-dependent binary sequences and study various types of success runs (overlapping, non-overlapping, exact, etc.) by examining additive functionals based on state visits and transitions in an appropriate Markov chain. We establish a multivariate Central Limit Theorem for the number of these types of runs and obtain its covariance matrix by means of the recurrent potential matrix of the Markov chain. Explicit expressions for the covariance matrix are given in the Bernoulli and a simple Markov-dependent case by expressing the recurrent potential matrix in terms of the stationary distribution and the mean transition times in the chain. We also obtain a multivariate Central Limit Theorem for the joint number of non-overlapping runs of various sizes and give its covariance matrix in explicit form for Markov dependent trials.     

Trajectories of Gambling During Adolescence

This study aimed at empirically identifying groups of adolescents with distinct longitudinal trajectories of gambling involvement and validating these groups by comparing them with respect to correlates. 903 low SES boys were followed annually from age 11 to 16 years. Three groups were found: an early-onset high-level chronic group, a late-onset high-level group, and a low gambler group. The Chronic group and the Low group consistently differed on teacher-rated inhibition (i.e., anxiety) during childhood and early adolescence. They also differed on concurrent teacher and self ratings of disinhibition (i.e., impulsivity), while the Late Onset group appeared to lie in between these groups. Compared to the Low group, both high groups subsequently had elevated scores on later gambling related problems.