Variance estimation for integrated population models

State-space models are widely used in ecology. However, it is well known that in practice it can be difficult to estimate both the process and observation variances that occur in such models. We consider this issue for integrated population models, which incorporate state-space models for population dynamics. To some extent, the mechanism of integrated population models protects against this problem, but it can still arise, and two illustrations are provided, in each of which the observation variance is estimated as zero. In the context of an extended case study involving data on British Grey herons, we consider alternative approaches for dealing with the problem when it occurs. In particular, we consider penalised likelihood, a method based on fitting splines and a method of pseudo-replication, which is undertaken via a simple bootstrap procedure. For the case study of the paper, it is shown that when it occurs, an estimate of zero observation variance is unimportant for inference relating to the model parameters of primary interest. This unexpected finding is supported by a simulation study.     

Invisible Scars: Comparing the Mental Health of LGB and Heterosexual Intimate Partner Violence Survivors

Intimate partner violence (IPV) affects countless women and men in lesbian, gay, and bisexual (LGB) as well as heterosexual relationships, but few studies have examined how such abuse is associated with the mental health of LGB victims. The present study addresses this issue using data from the 2006 Behavioral Risk Factor Surveillance System (BRFSS) survey to examine differences in depression and anxiety among IPV victims in LGB and heterosexual partnerships. The findings indicate LGB IPV victims are much more likely to have a history of depression (OR 1.70, p < .05) and anxiety (OR 1.70, p < .05) than heterosexual victims. These differences are slightly mediated by the victim’s perceived emotional support but not the type of abuse experienced. Our findings accentuate the need for greater inclusion of LGB persons in the IPV and mental health discourse, as well as the importance of social support for IPV victims. Policy implications for members of the LGB community are discussed.     

Young adults and casual sex: the relevance of college drinking settings

This study investigated the relevance of college drinking settings on the likelihood of students having sexual intercourse with a stranger. A random sample of 7,414 undergraduates at 14 public California universities responded to questions regarding frequency of attendance at six different setting types since the beginning of the semester (e.g., Greek, residence-hall parties, and bars or restaurants), drinking behavior, and sexual activity. Multi-level modeling examined the association between each setting type and the occurrence of alcohol-related sexual intercourse with a stranger. Findings indicated strong, positive associations between frequency of attendance at Greek parties, residence-hall parties, off-campus parties, and the occurrence of alcohol-related sex with a stranger. Frequency of attending the six settings and proportion of times drunk at the settings were also positively associated with alcohol-related sex with a stranger. Efforts aimed at preventing outcomes associated with casual sex (e.g., pregnancy, sexually transmitted infections, or mental health) should target specific drinking settings where students might be at high risk for risky alcohol use and unsafe sex behaviors.     

Exceptions to High School Dropout Predictions in a Low-Income Sample: Do Adults Make a Difference?

Adult–child relationship factors were examined to determine whether they differentiated between individuals who follow expected versus unexpected educational pathways. Low-income participants (96 men, 83 women) in the United States were followed from birth through age 23. Individuals were identified who followed expected versus unexpected pathways to high school graduation or dropping out based on academic achievement and behavioral problems. Patterns of parental involvement in school were significantly different between expected dropouts and unexpected graduates in middle childhood. In contrast, expected graduates had higher levels of parent involvement in middle childhood, more supportive parent–child relationships in early adolescence, and higher levels of social competence with adults than unexpected dropouts .     

Temporal (In)Stability of Employee Preferences for Rewards

This study examined the temporal stability of employee preferences for rewards over seven monthly evaluations. Participants completed a ranking stimulus preference assessment monthly, and the latter six monthly assessments were compared to the initial assessment. Correlations of preferences from month to month ranged from r = ?.89 to .99. Contrary to the stationarity axiom of rational choice economic theory, but consistent with a behavioral economic perspective, preferences for rewards changed across time for all participants and sometimes even reversed for some. This temporal instability suggests that organizations implementing incentive programs using preference assessments should periodically re-evaluate employee reward preferences and not assume temporal constancy of preferences.     

Perceived Parental Relationships and Health‐Risk Behaviors in College‐Attending Emerging Adults

The present study investigated the association of perceived parenting with health‐risk behaviors in an ethnically diverse sample of 1,728 college‐attending emerging adults. Participants completed retrospective measures of perceived maternal and paternal nurturance, connection, psychological control, and disrespect and reported their frequency of binge drinking, illicit drug use, unsafe sexual behavior, and impaired driving. Multivariate Poisson regression analyses indicated that perceived paternal acceptance was associated inversely with 6 of the 12 health‐risk behaviors measured, whereas perceived mothering was related only to 2 of these health‐risk behaviors. These patterns were consistent across gender, ethnicity, and family structure.     

In Living Memory: The Demographic Dynamics of Event Recollection in a Stable Population*

We model a stable population that has experienced an important historical event and the declining proportion, as time passes, of the population that remembers that event. The proportion is determined by the demographic characteristics of the population, including its age distribution, the natural rate of growth, the underlying birth rate, the life table probabilities to which the population is subject, and the effects of immigration and emigration under alternative assumptions about the nature of the event. (We distinguish between “local” and “universal” events.) It is determined also by the choice of an age of awareness of children at the time the event occurred. We preface development of the model by noting examples of major events of the kind we have in mind and, after development, explore the model's sensitivity to different parameter specifications by experimental simulation. The output of each experiment is a sequence of “remembering” proportions at successive decade intervals and the corresponding mean ages of the “rememberers” in relation to the overall mean age of the population.     

A Cross-National Analysis of Militarization and Well-Being Relationships in Developing Countries

We focus upon linkages between militarization and development in Third-World countries. The theoretical and empirical literature variously ascribes positive or negative developmental consequences to militarization. Part of this ambiguity results from an empirical focus solely on the impacts of national defense spending on growth in the gross national product. We expand our analysis to includethreecomponents of militarization (military regimes, participation in the military, and the importation of military hardware), as influences onthreeforms of national development (economic growth, accumulation of human capital, and growth in political rights). An important part of our analysis is the use of regression techniques that address the untoward consequences of a variety of regression problems, that are for the most part untreated in conventional analyses. We find with these techniques that militarization significantly impacts development in readily interpretable ways.