More Kin,Less Support: Multipartnered Fertility and Perceived Support Among Mothers

Recent research has documented the high prevalence of having children with more than 1 partner, termed multipartnered fertility. Because childbearing is an important mechanism for building kin networks, we theorize that multipartnered fertility will influence the availability of social support for mothers. Analyzing 3 waves of data from the Fragile Families study (N = 12,259), we find that multipartnered fertility is negatively associated with the availability of financial, housing, and child‐care support. Our longitudinal evidence suggests a bidirectional relationship in which multipartnered fertility reduces the availability of support, and the availability of support inhibits multipartnered fertility. We conclude that smaller and denser kin networks seem to be superior to broader, but weaker kin ties in terms of perceived instrumental support.     

Mentoring in a Post-Affirmative Action World

Mentoring can be an effective strategy in improving retention of college students and faculty from fields where historical underrepresentation has occurred. This article reviews the benefits of mentoring in higher education, and identifies components of effective mentoring strategies that promote educational and career advancement. It illustrates how effective programs can be institutionalized and scaled through consortial and national collaborations. Traditional and alternative mentoring models are described through four successful programs designed to increase the academic and professional success of undergraduates, graduate students, and junior faculty. The article concludes with a set of general recommendations and caveats gleaned from the literature and programs reviewed.     

Costs of reproduction: Assessing responses to brood size manipulation on life-history and behavioural traits using multi-state capture-recapture models

Costs of reproduction are fundamental trade-offs shaping the evolution of life histories. There has been much interest, discussion and controversy about the nature and type of reproductive costs. The manipulation of reproductive effort (e.g. brood size manipulation) may alter not only life-history traits such as future adult survival rate and future reproductive effort, but also behavioural decisions affecting recapture/resighting and dispersal probabilities. We argue that many previous studies of the costs of reproduction may have erroneously concluded the existence or non-existence of such costs because of their use of local return rates to assess survival. In this paper, we take advantage of the modern multistate capture-recapture methods to highlight how the accurate assessment of the costs of reproduction requires incorporating not only recapture probability, but also behavioural 'state' variables, for example dispersal status and current reproductive investment. The inclusion of state-dependent decisions can radically alter the conclusions drawn regarding the costs of reproduction on future survival or reproductive investment. We illustrate this point by re-analysing data collected to address the question of the costs of reproduction in the collared flycatcher and the great tit. We discuss in some detail the methodological issues and implications of the analytical techniques.     

Consistency of the beta kernel density function estimator

The authors give the exact asymptotic behaviour of the expected average absolute error of a beta kernel density estimator proposed by Chen (1999). They also prove the uniform weak consistency of this estimator for the class of continuous densities.     

Effects of sleep inertia on cognitive performance following a 1-hour nap

Abstract

This study investigated the effects of a 1-h nap on subsequent performance in spatial memory (SM) and logical reasoning (LR) tasks. The objective was to evaluate the duration of the effects of sleep inertia (SI). The performance was measured in two independent groups of subjects. The 1-h nap took place at 00:00 h in group 1 and at 03:00 h in group 2. In each task, the experimental design comprised one no-nap condition in which subjects had no sleep before the night tests, and a nap condition that comprised the 1-h nap followed by the test sessions. To measure the duration of SI effects, the subjects were tested in two 30-min sessions and the data in each session were analysed in sub-units of time of 3 min each. In each task the results showed no effects on accuracy, and no circadian effects of napping were found. In each task, analyses of pooled data of the two groups showed that the performance in the 1-h nap condition exhibited significant reductions of speed immediately following awakening, when compared with no-nap, reflecting SI effects. In SM, the slowing lasted 24 min, and 27 min in LR. Practical implications of the results are discussed.     

Predictors of Quality of Life in Economically Disadvantaged Populations in Montreal

Most epidemiological studies agree that economically disadvantaged populations are the groups most vulnerable to mental health problems and report lower quality of life among these populations. However, it appears that access to social support plays a role in protecting against the chronic stress resulting from conditions such as poverty. This study is an attempt to clarify the relative contribution of social support to the quality of life of economically disadvantaged populations in two low-income neighbourhoods of Montreal. A random sample of 417 social assistance recipients were interviewed in the respondents?? homes. The Quality of Life scale used was the Satisfaction with Life Domains Scale. The availability of social support components was assessed using the Social Provisions Scale. Social support measures were entered into a multidimensional model that included a number of variables identified as having a relationship to mental health. Among the 17 variables included in a multiple regression analysis, emotional support and support providing reassurance of worth accounted for most of the variance in the QOL predicted by the model. Psychological distress also accounted for a fair amount of variance in QOL and younger people and people experiencing food insecurity showed a lower QOL.     

Probabilistic Modeling of the Fate of Listeria Monocytogenes in Diced Bacon During the Manufacturing Process

To assess the impact of the manufacturing process on the fate of Listeria monocytogenes, we built a generic probabilistic model intended to simulate the successive steps in the process. Contamination evolution was modeled in the appropriate units (breasts, dice, and then packaging units through the successive steps in the process). To calibrate the model, parameter values were estimated from industrial data, from the literature, and based on expert opinion. By means of simulations, the model was explored using a baseline calibration and alternative scenarios, in order to assess the impact of changes in the process and of accidental events. The results are reported as contamination distributions and as the probability that the product will be acceptable with regards to the European regulatory safety criterion. Our results are consistent with data provided by industrial partners and highlight that tumbling is a key step for the distribution of the contamination at the end of the process. Process chain models could provide an important added value for risk assessment models that basically consider only the outputs of the process in their risk mitigation strategies. Moreover, a model calibrated to correspond to a specific plant could be used to optimize surveillance.