Landscape Context Influences the Abundance and Richness of Native Lady Beetles Occupying Urban Vacant Land

Urban Ecosystems - Urban insect communities are structured by hierarchical filters including regional processes, human facilitation, and species interactions. We sought to inform future urban...     

Multiple event times in the presence of informative censoring: modeling and analysis by copulas

Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.

     

An Empirical Model of Perceived Mortality Risks for Selected U.S. Arsenic Hot Spots

Researchers have long recognized that subjective perceptions of risk are better predictors of choices over risky outcomes than science‐based or experts’ assessments of risk. More recent work suggests that uncertainty about risks also plays a role in predicting choices and behavior. In this article, we develop and estimate a formal model for an individual's perceived health risks associated with arsenic contamination of his or her drinking water. The modeling approach treats risk as a random variable, with an estimable probability distribution whose variance reflects uncertainty. The model we estimate uses data collected from a survey given to a sample of people living in arsenic‐prone areas in the United States. The findings from this article support the fact that scientific information is essential to explaining the mortality rate perceived by the individuals, but uncertainty about the probability remains significant.     

Good 'traction' can help you achieve change

Examine the abstract idea of traction. Explore how traction in your job can help you motivate meaningful change.     

Identity Deployment and Social Change: Understanding Identity as a Social Movement and Organizational Strategy1

In this article, we discuss the theoretical implications of empirical elaborations of Bernstein’s (1997) model of identity deployment. New research encompasses a diverse array of venues and targets and elaborates on the mechanisms through which identities may be deployed strategically. Application of the identity deployment model spans a variety of so‐called ‘identity movements’ as well as ethnic, nationalist and indigenous movements, and community mobilization. Identity deployment is also a useful strategy in organizational and professional contexts, as in the micro‐brewery movement or culinary movements, demonstrating the theoretical generalizability of the original model. New research closely examines the relationship between identity and strategy and the conditions that affect activists’ choice of identity strategies as well as the situations where they might avoid identity strategies altogether. Research finds that identities may be deployed performatively, rhetorically or discursively. Identity deployment may be facilitated by emotional displays, music and ritual. The way that power and authority are organized in a given venue determines in part the capacity of activists and organizations to alternate between celebrating and suppressing difference from the majority. Identity deployment influences internal and external outcomes, affecting mobilization and goal achievement. Finally, feedback loops link the different analytic dimensions of identity.     

Positive and negative affect: A maximum-likelihood approach

Using the LISREL maximum-likelihood program, the relation between Bradburn's positive affect and negative affect scales is examined for three age groups of adults. It is found that (a) unequal item loadings fit significantly better than equal item loadings; (b) the best-fitting loadings for the elderly are significantly different from those of the non-elderly; (c) the positive and negative affect scales are substantially correlated and (d) correlations with related variables are stronger when positive and negative affect scales are formed by maximum-likelihood loadings rather than by unit loadings. Given the widespread use of Bradburn's scales, implications of these results for subjective well-being are discussed.     

Exploring self-care among dementia caregivers:the role of perceived support in accomplishing exercise goals

Support provided by family and friends may influence the extent to which older women who are primary caregivers for a spouse with dementia adhere to an exercise routine. The current study reports on qualitative interviews with 30 older female caregivers taking part in an exercise intervention regarding the support they received for their exercise goals. Results indicate that nearly all women received some level of verbal encouragement from family and friends, though far fewer had exercise partners or someone to stay with their husbands while they exercised. To reflect the wide variation observed in the amount of exercise support received and needed by caregivers, a typology of support situations was constructed as follows: Self-reliant, Well-supported, Under-supported, and Superfluous support. Implications for future exercise interventions targeting this population are discussed.     

Food insufficiency and physical and mental health in a longitudinal survey of welfare recipients

Food insufficiency is a significant problem in the United States, and poor African American women with children are at especially high risk. An inadequate household food supply can potentially affect the well-being of household members, but it is difficult to distinguish the effects of food insufficiency from risk factors for poor health that are also common among the food insufficient, such as poverty. We examined food insufficiency and physical and mental health among African American and white women (n = 676) who were welfare recipients in 1997. Controlling for common risk factors, women who reported food insufficiency in both 1997 and 1998 were more likely to report fair or poor health at the later date. Food insufficiency in 1998 was significantly associated with meeting the diagnostic screening criteria for recent major depression. Food insufficiency at both times and in 1998 only was related to women's sense of mastery. These findings add to growing evidence that household food insufficiency is associated with poor physical and mental health.