Passive versus active parental permission in school-based survey research: does the type of permission affect prevalence estimates of risk behaviors?

This study investigates whether the type of parental permission affects prevalence estimates for risk behaviors from the national 2001 Youth Risk Behavior Survey. Participants were 13,195 students from 143 schools, of which 65% used passive permission and 35% active permission. Student participation rates were 86.7% in passive permission schools and 77.3% in active permission schools. For 24 of 26 behaviors tested, no significant differences were seen in the prevalence of risk behavior by type of parental permission. As long as high response rates are obtained, type of parental permission does not affect prevalence estimates for risk behaviors that are based on self-report.     

Determinants of urban tree canopy in residential neighborhoods: Household characteristics, urban form, and the geophysical landscape

The aesthetic, economic, and environmental benefits of urban trees are well recognized. Previous research has focused on understanding how a variety of social and environmental factors are related to urban vegetation. The aim is often to provide planners with information that will improve residential neighborhood design, or guide tree planting campaigns encouraging the cultivation of urban trees. In this paper we examine a broad range of factors we hypothesize are correlated to urban tree canopy heterogeneity in Salt Lake County, Utah. We use a multi-model inference approach to evaluate the relative contribution of these factors to observed heterogeneity in urban tree canopy cover, and discuss the implications of our analysis. An important contribution of this work is an explicit attempt to account for the confounding effect of neighborhood age in understanding the relationship between human and environmental factors, and urban tree canopy. We use regression analysis with interaction terms to assess the effects of 15 human and environmental variables on tree canopy abundance while holding neighborhood age constant. We demonstrate that neighborhood age is an influential covariate that affects how the human and environmental factors relate to the abundance of neighborhood tree canopy. For example, we demonstrate that in new neighborhoods a positive relationship exists between street density and residential tree canopy, but the relationship diminishes as the neighborhood ages. We conclude that to better understand the determinants of urban tree canopy in residential areas it is important to consider both human and environmental factors while accounting for neighborhood age.     

Ethical Considerations in Sex Therapy

The most ethical sex therapy is that which cures the symptom and improves the marital relationship in the briefest time at the least cost. Neither insight therapy, nor direct sexual interaction with the client satisfy these criteria. Examples are given of effective ethical therapies, useful in male and female sexual dysfunctions.