Designing two factor experiments for selecting interactions

This paper considers the problem of devising a single stage procedure for selecting the treatment combination associated with the largest interaction in a two-factor rfx× c experiment having independent normally distributed observations with common known variance. The intuitive procedure based on the best linear unbiased estimators of the population interactions is employed. Initially an indifference zone formulation is used; the problem of determining the least favorable configuration is reduced to a nonlinear programming problem with log concave objective function and a convex polytope as feasible region. A solution technique is introduced in the context of an illustrative example. The problem is also considered using a preferred population formulation; this approach requires a strengthened version of the indifference zone probability requirement. It is shown that the same sample size guarantees this requirement as does the earlier one.     

Neighborhood context and racial differences in early adolescent sexual activity

Evidence suggests that African American youths initiate sexual activity at earlier ages than do European American or Latino youths. Using data from a multilevel study in Chicago, we developed and tested a neighborhood-based model of the timing of first adolescent intercourse that emphasizes the impact of neighborhood structural disadvantage and collective efficacy on early sexual activity (at ages 11 to 16). In turn, we explored the extent to which neighborhood factors account for racial differences in the timing of first intercourse. The findings indicate that demographic background, family processes, peer influences, and developmental risk factors account for about 30% of the baseline increased likelihood of early sexual onset for African American youths compared with European American youths. However, a significant residual racial difference remained even after we considered a host of micro-level factors. Neighborhood-level concentrated poverty largely explained this residual racial difference. Collective efficacy also independently contributed to the delay of sexual onset. No significant baseline difference in age of sexual initiation was found between Latino and European American youths.     

Effect of family structure on life satisfaction: australian evidence

How do family arrangements affect subjective well-being? We investigate this issue using data pooled from the IsssA and HILDA, both large, representative national samples of Australia (pooled n=38 447). Our regression analysis of cross-sectional and panel data examines how large are the differences in life satisfaction according to marital status and cohabitation. We find that women and men in formal marriages experience higher levels of life satisfaction than do people in other family arrangements. Moreover, both multiple tests in the cross-section, and tests controlling for prior happiness in the panel analysis, suggest that this is a causal relationship. Aggregating up the levels of life satisfaction generated by different marriage and cohabitation arrangements across a lifetime, suggests that a life-long marriage is the most satisfying. Early divorce followed by an enduring second marriage is little worse (because little time is spent outside the married state). But divorce without remarriage, or long lasting cohabitation without formal marriage, reduce the lifetime sum of subjective well-being by 4–12% for both women and men.     

Combining Food Frequency and Survey Data to Quantify Long-Term Dietary Exposure: A Methyl Mercury Case Study

Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.     

Auf dem Weg an die Spitze Anforderungen an Bewerber für Top-Positionen

En route to the top. Requirements on candidates for top positionsThe assessment of candidates for positions as managing director or as an executive committee member by means of management diagnostics has been frowned upon by German companies for a long time. There has, however, been a clear change of opinion regarding this matter in the meantime. The authors have developed a model of requirements to assess the competencies and potential critical for success. Six areas of responsibility are differentiated between thereby: “Ability to cope with complexity” and “development of decidedness”, “Will to create” and “establishment of structures”, “Establishment of bonds” and “ability of self-management”, and are divided into three levels: the personal level, the co-operative level and the level of corporate culture respectively.     

Imaginandose Mexicano: The Symbolic Context of Mexican American Ethnicity Beyond the Second Generation

This study explores how third-plus-generation Mexican Americans are able to perpetuate Mexican ethnicity within the relatively integrated environments they occupy in and around Phoenix, Arizona and San Jose, California. By using an imaginary approach in this analysis, I seek to demonstrate the limited applicability of the symbolic ethnicity approach for this group, in particular, as well as to downplay thinking about culture as a set of traits or fixed characteristics that define an ethnic subgroup. I do this through an exploration of how the third-plus-generation Mexican Americans interviewed for this study utilize a range of relational resources—specifically, religion, Spanish-language television, and cross-national encounters—to reinforce and recreate Mexican ethnicity in their day-to-day lives.     

Cognitive-behavioral treatment for adolescents who sexually offend and their families: individual and family applications in a collaborative outpatient program

This article describes an outpatient treatment program for adolescent sexual abusers that was established by a mental health agency in collaboration with a specialized probation program in the juvenile court. Individualized treatment is based on a comprehensive clinical assessment with the youth and guardian, for which examples are provided. Given the heterogeneity of this population, we describe several treatment strategies directed to various individual or family clinical targets, including psychiatric disorders, sexual deviance and sexuality, normal adolescent development and adaptive skills, and parent and family relationships. Ongoing collaborative and coordination issues are also reviewed. The integration of mental health and probationary services provides a balanced approach to the community management and treatment of the low-risk, primarily first-time, adolescent sexual offender.     

Inequality and welfare evaluation of heterogeneous income distributions

This paper establishes the principles that should govern the welfare and inequality analysis of heterogeneous income distributions. Two basic criteria – the equity preference condition and the compensation principle – are shown to be fundamentally incompatible. The paper favours the latter, thereby vindicating the traditional method of dealing with heterogeneous samples. However, inequality and welfare comparisons will usually be well defined only if equivalent incomes are obtained using constant scale factors; and researchers will need to distinguish clearly between inequality of nominal incomes and inequality of living standards. Furthermore, household observations must always be weighted according to family size.     

A weighted polynomial regression method for local fitting of spatial data

Typically, parametric approaches to spatial problems require restrictive assumptions. On the other hand, in a wide variety of practical situations nonparametric bivariate smoothing techniques has been shown to be successfully employable for estimating small or large scale regularity factors, or even the signal content of spatial data taken as a whole.We propose a weighted local polynomial regression smoother suitable for fitting of spatial data. To account for spatial variability, we both insert a spatial contiguity index in the standard formulation, and construct a spatial-adaptive bandwidth selection rule. Our bandwidth selector depends on the Gearys local indicator of spatial association. As illustrative example, we provide a brief Monte Carlo study case on equally spaced data, the performances of our smoother and the standard polynomial regression procedure are compared.This note, though it is the result of a close collaboration, was specifically elaborated as follows: paragraphs 1 and 2 by T. Sclocco and the remainder by M. Di Marzio. The authors are grateful to the referees for constructive comments and suggestions.