Some properties of generalized ridge estimators

Exact expressions, in the form of infinite series expansions, are given for the first and second moments of two well known generalized ridge estimators. These series expansions are then evaluated using recursive formulas and computations are verified using approximations. Results are presented for the relative mean square error and bias of these estimators as well as their relative efficiency with respect to least squares.     

Help or hindrance? Social policy and the ‘social determinants of health’

In recent years, public health research has become increasingly focused on issues of social inequality and social disadvantage. This is because social issues, such as poor housing and unemployment, have been found to impact health significantly, and are now referred to as ‘the social determinants of health‘. As a result of this shift, public health is now principally concerned with what are historically considered to be social policy issues. This paper discusses the confluence of public health and social policy; it examines the opportunities and risks posed by this convergence for those working in social policy seeking to reduce poverty and inequality. We argue that, while much can be gained in the two fields by working more closely together, there remain fundamental differences in perspectives and approaches. In order to maximise benefits, these points of difference need to be thought through sooner rather than later.     

Revising the standard wisdom of C. elegans natural history: ecology of longevity

Here, we consider that most of the research concerning Caenorhabditis elegans has been laboratory focused and that only limited research has directly considered the worm's biology relative to its natural history in the wild. We describe that, although the worm has traditionally been considered a soil nematode, we could not find it in soil but frequently recovered it from snails. Finally, we discuss how a better understanding of the natural history of C. elegans may enhance its usefulness as a model organism for studying aging and other phenomena.     

Condom Failure: Examining the Objective and Cultural Meanings Expressed in Interviews With African American Adolescents

The purpose of this study was to explore the meaning and context of self-reported “condom failure” among sexually active African American adolescents. Semistructured interviews regarding methods of protection from pregnancy and sexually transmitted disease (STD) with 124 youth (ages 14–19 years) were content analyzed. The findings suggested three meanings of condom failure. First, condom failure represents a legitimate and important risk related to sexual activity. Second, it can serve as an excuse repertoire for adolescents who engaged in unprotected sex and later experienced either pregnancy or a STD. Third, it may serve as an explanation for males who deceive their partners into having unprotected sex. The findings are discussed with regard to their implications for HIV or STD prevention and research.     

“Feeling frumpy”: The relationships between body image and sexual response changes in midlife women

This study investigated the relationships between self‐rated attractiveness and self‐reported sexual response changes (over the past decade) and current sexual satisfaction in 307 heterosexual, midlife women. Results indicated that regardless of the woman's specific age, she was more likely to consider herself more attractive when she was 10 years younger, and her self‐perceived attractiveness did not significantly differ based on her menopausal status. The more a woman perceived herself as less attractive than before, the more likely she was to report a decline in sexual desire or frequency of sexual activity. The more she perceived herself as attractive, the more likely she was to experience an increase in sexual desire, orgasm, enjoyment, or frequency of sexual activity. There were no significant statistical relationships between a woman's perception of her own attractiveness as she aged and her current sexual satisfaction.