Order statistics from trivariate normal and -distributions in terms of generalized skew-normal and skew- distributions

We consider here a generalization of the skew-normal distribution, GSN(λ₁,λ₂,ρ), defined through a standard bivariate normal distribution with correlation ρ, which is a special case of the unified multivariate skew-normal distribution studied recently by Arellano-Valle and Azzalini [2006. On the unification of families of skew-normal distributions. Scand. J. Statist. 33, 561–574]. We then present some simple and useful properties of this distribution and also derive its moment generating function in an explicit form. Next, we show that distributions of order statistics from the trivariate normal distribution are mixtures of these generalized skew-normal distributions; thence, using the established properties of the generalized skew-normal distribution, we derive the moment generating functions of order statistics, and also present expressions for means and variances of these order statistics.Next, we introduce a generalized skew-t_ν distribution, which is a special case of the unified multivariate skew-elliptical distribution presented by Arellano-Valle and Azzalini [2006. On the unification of families of skew-normal distributions. Scand. J. Statist. 33, 561–574] and is in fact a three-parameter generalization of Azzalini and Capitanio's [2003. Distributions generated by perturbation of symmetry with emphasis on a multivariate skew t distribution. J. Roy. Statist. Soc. Ser. B 65, 367–389] univariate skew-t_ν form. We then use the relationship between the generalized skew-normal and skew-t_ν distributions to discuss some properties of generalized skew-t_ν as well as distributions of order statistics from bivariate and trivariate t_ν distributions. We show that these distributions of order statistics are indeed mixtures of generalized skew-t_ν distributions, and then use this property to derive explicit expressions for means and variances of these order statistics.     

Semiparametric estimation for count data through weighted distributions

This paper is concerned with semiparametric discrete kernel estimators when the unknown count distribution can be considered to have a general weighted Poisson form. The estimator is constructed by multiplying the Poisson estimate with a nonparametric discrete kernel-type estimate of the Poisson weight function. Comparisons are then carried out with the ordinary discrete kernel probability mass function estimators. The Poisson weight function is thus a local multiplicative correction factor, and is considered as the uniform measure to detect departures from the equidispersed Poisson distribution. In this way, the effects of dispersion and zero-proportion with respect to the standard Poisson distribution are also minimized. This method of estimation is also applied to the weighted binomial form for the count distribution having a finite support. The proposed estimators, in addition to being simple, easy-to-implement and effective, also outperform the competing nonparametric and parametric estimators in finite-sample situations. Two examples illustrate this new semiparametric estimation.     

Nonparametric control charts based on runs and Wilcoxon-type rank-sum statistics

In this article, we introduce three new distribution-free Shewhart-type control charts that exploit run and Wilcoxon-type rank-sum statistics to detect possible shifts of a monitored process. Exact formulae for the alarm rate, the run length distribution, and the average run length (ARL) are all derived. A key advantage of these charts is that, due to their nonparametric nature, the false alarm rate (FAR) and in-control run length distribution is the same for all continuous process distributions. Tables are provided for the implementation of the charts for some typical FAR values. Furthermore, a numerical study carried out reveals that the new charts are quite flexible and efficient in detecting shifts to Lehmann-type out-of-control situations.     

Communication in assisted living

This study of communication in an Assisted Living Facility (ALF) focuses on staff's interpretive frameworks and situational tactics for managing elderly residents. It is based on interviews with staff and residents in an ALF together with ethnographic fieldwork. As in other quasi-total institutions, staff members engage in control as well as care, monitoring residents for compliance with rules and directives. Residents, aware of the threat of being moved to a nursing home, also monitor their own behavior and cognition in comparison to other residents. Other communication issues include the infantilization of the elderly by staff, and the race, class, and ethnic prejudices of residents.     

Adolescent Deliberate Self‐Harm: Linkages to Emotion Regulation and Family Emotional Climate

Parents' responses to their children's emotional expressivity have been shown to significantly influence children's subsequent psychosocial functioning. This study hypothesized that adolescents' deliberate self‐harm (DSH) may be an outcome associated with poor emotion regulation as well as an invalidating family environment. The mediational role of specific emotion processes (i.e., poor awareness of emotion, difficulties expressing emotions) between family emotional environment and the frequency of DSH was examined with 131 psychiatrically hospitalized adolescents (M age=14.84 years, SD=1.75 years). Results indicated that adolescents who self‐injured reported that this behavior reduced their negative emotional states. Structural equation modeling provided support for the proposed model that family climate influences frequency of DSH through emotion regulation skills but the model held for girls only. A direct model effect was not supported. Emotion regulation partially mediated the relationship between family climate and DSH, and direct effects were also observed.     

Persistence of an exclusionary model: Inequality and segmentation in Mexican society

Beginning in the 1980s, Mexico's social and labour policies took a neoliberal turn which exacerbated inequalities, poverty and social exclusion. The change of policy course that has occurred over the past decade has so far failed to bring about a critical review of the country's economic model and its social consequences. The role of the State has been systematically cut back; social services have been outsourced to the market; and informal family‐based social protection has gained ground. Mexico's social model has thus been reduced to a system that is almost exclusively concerned with protection for those living in extreme poverty.     

Nest predators,but not nest survival,differ between adjacent urban habitats

Growing human populations make it imperative for ecologists to identify strategies to conserve biodiversity in human-dominated landscapes, such as cities. Effects of urbanization on birds are particularly well-studied, but questions remain regarding the best conservation approaches. Debate about the relative utility of focusing conservation efforts on nature reserves versus developed lands has focused largely on comparing species abundance or presence, with few studies addressing underlying behavioral or demographic mechanisms. Here we evaluated differences in avian reproductive success in nature reserves and matrix habitats to test the assumption that nest predation is lower within areas protected from development. Specifically, we investigated 1) whether nest survival differed in replicated pairs of forest parks and residential neighborhoods and 2) whether differences in nest survival were associated with changes in which species most frequently depredated nests. From April–August 2007–2014, we monitored nests of two native birds, American robin (Turdus migratorius) and northern cardinal (Cardinalis cardinalis), and video-documented nest predators in paired forest-matrix habitats in the Columbus, Ohio metropolitan area. We found similar rates of nest survival in the two habitats for both robins (Χ²₁?=?0.715, p?=?0.398, n?=?741 nests) and cardinals (Χ²₁?=?0.926, p?=?0.336, n?=?1156 nests), but interactions between predators and prey differed. In particular, domestic cats (Felis catus) were over five times as likely to depredate cardinal nests in matrix habitats versus forest parks (Χ²₁?=?7.24, simulated p?=?0.010; n_forest?=?3, n_matrix?=?7). Our results suggest that at least in some circumstances, nest success of native birds may be equivalent between nature reserves and adjacent residential matrix habitats, and thus residential neighborhoods may contribute positively to bird conservation in urban landscapes.     

Barriers and Facilitators of Responding to Problem Gambling: Perspectives from Australian Mental Health Services

Despite high rates of comorbidity between problem gambling and mental health disorders, few studies have examined barriers or facilitators to the implementation of screening for problem gambling in mental health services. This exploratory qualitative study identified key themes associated with screening in mental health services. Semi-structured interviews were undertaken with 30 clinicians and managers from 11 mental health services in Victoria, Australia. Major themes and subthemes were identified using qualitative content analysis. Six themes emerged including competing priorities, importance of routine screening, access to appropriate screening tools, resources, patient responsiveness and workforce development. Barriers to screening included a focus on immediate risk as well as gambling being often considered as a longer-term concern. Clinicians perceived problem gambling as a relatively rare condition, but did acknowledge the need for brief screening. Facilitators to screening were changes to system processes, such as identification of an appropriate brief screening instrument, mandating its use as part of routine screening, as well as funded workforce development activities in the identification and management of problem gambling.     

Urbanisation: an economic overview of some of the issues

"The paper presents a discussion of the economic justification for taking cities seriously, a section outlining the scale of urbanisation and some of the issues raised, a section that discusses the policy approaches, one that looks at the local agencies for the formulation and execution of policy, and a short final part on some of the implications for aid policy." The focus is on the importance of the urban sector for economic development in developing countries.