Linearity of regression for non-adjacent record values

Let X₁,X₂,… be a sequence of iid random variables having a continuous distribution; by R₁,R₂,… denote the corresponding record values. All the distributions allowing linearity of regressions either E(R_m+k|R_m) or E(R_m|R_m+k) are identified.     

Environmental Tobacco Smoke: Exposure-Response Relationships in Epidemiologic Studies

Demonstration of a dose-response relationship for environmental tobacco smoke (ETS) is an important indication of causality. Central to the analysis and interpretation of dose-response relations as described in epidemiological studies is the relationship between dose and exposure. It must be recognized that in studies of ETS we have only surrogate measures of dose, and these surrogate measures (based on exposure) are imperfect. The question-based measures of ETS exposure generally have not been standardized, may have limited validity and reliability, and cannot comprehensively describe total ETS exposure, exposure to individual ETS components, nor doses of biologically relevant agents at target sites. Nevertheless, useful data have been yielded in epidemiologic studies linking ETS exposure to increased respiratory infection and symptoms, reduced lung growth in children, and increased lung cancer in nonsmoking adults. The more consistent exposure-response data for studies on acute health in children may reflect the greater difficulty in measuring exposure in studies of chronic health in adults.     

On the Complexity of Constructing Evolutionary Trees

In this paper we study a few important tree optimization problems with applications to computational biology. These problems ask for trees that are consistent with an as large part of the given data as possible. We show that the maximum homeomorphic agreement subtree problem cannot be approximated within a factor of , where N is the input size, for any 0 in polynomial time unless P = NP, even if all the given trees are of height 2. On the other hand, we present an O(N log N)-time heuristic for the restriction of this problem to instances with O(1) trees of height O(1) yielding solutions within a constant factor of the optimum. We prove that the maximum inferred consensus tree problem is NP-complete, and provide a simple, fast heuristic for it yielding solutions within one third of the optimum. We also present a more specialized polynomial-time heuristic for the maximum inferred local consensus tree problem.     

A blueprint for career change when you don't know what you want to do

Follow the paths of a gynecologist turned investment banker and an internist who became a medical writer. Both used a proven process to change their careers and determine what they wanted to do.     

Facilitators and barriers to employment: the perspectives of people with psychiatric disabilities and employment service providers

This study examined the perspectives of people with psychiatric disabilities and employment service providers regarding factors that most directly help or hinder consumer efforts to obtain and maintain employment. Forty-four adults with serious mental illness (SMI) (consumers) and 30 providers participated in 12 focus groups across Massachusetts. We began both consumer and provider groups by posing two broad questions: 1) what factors most help people with SMI get and keep jobs (facilitators), and 2) what factors most prevent people with SMI from getting and keeping jobs (barriers)? Data were analyzed qualitatively and both person and environmental factors were highlighted. Among facilitators, participants agreed that quality consumer-provider relationships and individualized employment services are most instrumental in helping consumers achieve employment goals. Participants identified a range of environmental barriers, including issues related to the service system, entitlement programs, non-human resources, and social stigma. Implications for services are discussed.     

Trajectories of gender role orientations in adolescence and early adulthood: a prospective study of the mental health effects of masculinity and femininity

Adolescence is the segment of the life course when gender differences in mental health emerge and gender becomes a more salient factor shaping orientations toward oneself and views of one's place in the social world. This study uses mixture modeling, to identify trajectories of masculinity and femininity between ages 12 and 25, and OLS regression, to examine the effects of those trajectories on mental health in young adulthood (measured as depressive symptoms and alcohol problems at age 25). Four waves of prospective data from the Rutgers Health and Human Development Project are used; respondents (n = 447) are age 12 at Wave 1 (1979-81), 15 at Wave 2 (1982-84), 18 at Wave 3 (1985-87), and 25 at Wave 4 (1992-94). Results indicate that having relatively high and increasing levels of masculinity over adolescence decreases depressive symptoms in early adulthood for both males and females. Reflecting the privileging of males over females, the findings suggest that masculinity, but not femininity, is a central axis on which advantages and disadvantages across some dimensions of mental health accumulate over adolescence.     

A Canadian experience with an intervention programme for vulnerable families: lessons for German social work and policy

Schools are an important community resource that can foster social connections and enhance the health and wellbeing of children and families in Germany through information, health promotion and interventions. While developing social connections between the school and vulnerable families—those who are most limited in their access to other sources of information, education and intervention—is complex and challenging, it is nonetheless critical. This paper reports on the role of Families and Schools Together (F&ST), a school-based intervention aimed at vulnerable families, in building and promoting the social connections, or social capital, that strengthen families and communities. Thematic analysis of semi-structured interviews revealed that programme participants perceived an increase in their social capital in all three of its dimensions (bonding, bridging and linking). The paper highlights the importance of social capital in building stronger, more resilient families and of strengthening relations between parents and schools, and contributes to the sharing of experience and views on matters concerning families in Germany.