Minimax estimation of a lower-bounded scale parameter of a gamma distribution for scale-invariant squared-error loss

Let X have a gamma distribution with known shape parameter θr;aL and unknown scale parameter θ. Suppose it is known that θ ≥ a for some known a > 0. An admissible minimax estimator for scale-invariant squared-error loss is presented. This estimator is the pointwise limit of a sequence of Bayes estimators. Further, the class of truncated linear estimators C = {θ_ρ|θ_ρ(x) = max(a, ρ), ρ > 0} is studied. It is shown that each θ_ρ is inadmissible and that exactly one of them is minimax. Finally, it is shown that Katz's [Ann. Math. Statist., 32, 136–142 (1961)] estimator of θ is not minimax for our loss function. Some further properties of and comparisons among these estimators are also presented.     

An empirical Bayes approach to outliers

A formulation of the problem of detecting outliers as an empirical Bayes problem is studied. In so doing we encounter a non-standard empirical Bayes problem for which the notion of average risk asymptotic optimality (a.r.a.o.) of procedures is defined. Some general theorems giving sufficient conditions for a.r.a.o. procedures are developed. These general results are then used in various formulations of the outlier problem for underlying normal distributions to give a.r.a.o. empirical Bayes procedures. Rates of convergence results are also given using the methods of Johns and Van Ryzin (1971, 1972).     

Depression and Missed Work among Informal Caregivers of Older Individuals with Dementia

Although providing informal care can negatively affect caregiver emotional health and lead to depression, the association between caregiver depression and missed work is unknown. We use data from the National Longitudinal Caregiver Survey to examine the relationship between caregiver depression and missed work among informal caregivers for older veterans with Alzheimer’s disease or vascular dementia. Two-part models are used to estimate the expected hours of work missed among working caregivers. Caregiver depression is statistically significantly associated with the likelihood and amount of time missed at work, resulting in an average of an extra half-day of work missed per month. While the effect of caregiver depression on work missed is modest, it represents another possible benefit from interventions to support caregivers.     

The Imaginary Audience and Personal Fable: Factor Analyses and Concurrent Validity of the “New Look” Measures

This study examined key components of the “New Look” at the imaginary audience and personal fable constructs. Toward this end, data from four samples of Belgian high school students (N= 1,458) were analyzed. Confirmatory and exploratory factor analyses failed to confirm that the measures associated with the New Look theory, the New Imaginary Audience Scale, and the New Personal Fable Scale (NPFS), tapped a common underlying construct. Only the invulnerability and omnipotence subscales of the NPFS proved to be highly related. In line with the New Look theory, boys were found to believe more strongly in their own uniqueness, invulnerability, and omnipotence than were girls. Higher scores on the invulnerability and omnipotence subscales were associated with lower levels of depression and loneliness. Finally, each aspect of the personal fable seemed to have its own specific role in the process of separation – individuation. Implications of these findings for the New Look theory of the imaginary audience and the personal fable are discussed. Suggestions for future research are put forth, with particular emphasis on the role of the invulnerability/omnipotence complex in adolescent development and behavior and on the family resemblances among the various aspects of the personal fable.     

Estimating precision,repeatability, and reproducibility from Gaussian and non- Gaussian data: a mixed models approach

Quality control relies heavily on the use of formal assessment metrics. In this paper, for the context of veterinary epidemiology, we review the main proposals, precision, repeatability, reproducibility, and intermediate precision, in agreement with ISO (international Organization for Standardization) practice, generalize these by placing them within the linear mixed model framework, which we then extend to the generalized linear mixed model setting, so that both Gaussian as well as non-Gaussian data can be employed. Similarities and differences are discussed between the classical ANOVA (analysis of variance) approach and the proposed mixed model settings, on the one hand, and between the Gaussian and non-Gaussian cases, on the other hand. The new proposals are applied to five studies in three diseases: Aujeszky's disease, enzootic bovine leucosis (EBL) and bovine brucellosis. The mixed-models proposals are also discussed in the light of their computational requirements.     

The Interplay Between Tonal Synchrony and Social Engagement in Mother–Infant Interaction

This study explores the relationship between tonal synchrony and maternal‐infant social engagement based on free‐play recordings of 15 mothers and their 3‐month‐old infants in a laboratory setting. Moment‐by‐moment analyses on a microlevel were used to study social engagement and vocal interaction. We analysed and categorized 854 vocalization periods (mother‐only vocalizations, tonal interaction periods, nontonal interaction periods, and mutual silence). Tonal synchrony was analysed in terms of harmonic and pentatonic series based on pitch frequency analyses. Social engagement was microanalyzed in terms of matched and mismatched engagement states. ANOVA‐repeated measures revealed, most importantly, a significant relationship between TIPs and social interaction repair, which indicates the importance of tonal synchrony in the flow of social engagement in mother–infant dyads. Other significant relationships were found between (a) nTIPs/mismatch–mismatch, and, (b) MOV/affect loss. As mentioned in the discussion, the findings are suggestive for clinical applications (e.g., music therapy) and warrant further research.     

The Formation of Group Affect and Team Effectiveness: The Moderating Role of Identification

In the current research we use the social identity perspective to enhance our understanding of group affect (i.e. a collectively shared pattern of affective states among group members). Because higher identification (i.e. the extent to which group members define themselves in terms of their group membership) is related to higher attentiveness to fellow group members, we expected that group identification would foster affective convergence, and that the effects of group affective tone on team effectiveness would be stronger for higher identifying groups. A survey of teams (n=71 teams) confirmed our expectations. A scenario experiment (n=121 participants) added to our findings by showing that identification does indeed lead group members to affectively converge to their fellow group members and that this affective convergence, in turn, explains subsequent team‐oriented attitudes. Our study testifies to the notion that team managers may want to take notice of and manage affect in work groups, because, especially in higher identifying teams, affect may spread among team members and influence the team's effectiveness.