Absolute Risk or Relative Risk? A Study of Intraspecies and Interspecies Extrapolation of Chemical‐Induced Cancer Risk

We have used the CBDS database of the National Toxicology Program to study the difference between absolute risk and relative risk models for interspecies and intersex predictions of cancer risk. For no combination (class) of tumor and site is the prediction good for all chemicals. The variation in predicted risk between chemicals exceeds the difference in risks resulting from application of these two models. On the whole, it appears that relative risk is a better model.     

Darwinism,organizational evolution and survival: key challenges for future research

How do social organizations evolve? How do they adapt to environmental pressures? What resources and capabilities determine their survival within dynamic competition? Charles Darwin’s seminal work The Origin of Species (1859) has provided a significant impact on the development of the management and organization theory literatures on organizational evolution. This article introduces the JMG Special Issue focused on Darwinism, organizational evolution and survival. We discuss key themes in the organizational evolution research that have emerged in recent years. These include the increasing adoption of the co-evolutionary approach, with a particular focus on the definition of appropriate units of analysis, such as routines, and related challenges associated with exploring the relationship between co-evolution, re-use of knowledge, adaptation, and exaptation processes. We then introduce the three articles that we have finally accepted in this Special Issue after an extensive, multi-round, triple blind-review process. We briefly outline how each of these articles contributes to understanding among scholars, practitioners and policy makers of the continuous evolutionary processes within and among social organizations and systems.     

The Role of Peer Social Capital in Educational Assimilation of Immigrant Youths*

The academic achievement of immigrant children has been a focus of social research for decades. Yet little attention has been paid to peer social capital and its importance as a school context factor for the academic success of immigrant youths. Using multilevel data from the National Longitudinal Study of Adolescent Health (Waves 1 and 3), this article draws upon social capital theory and assimilation theory to examine the effects of peer social capital on the academic achievement and attainment of immigrant and native youths. The effects of three measures of peer social capital are studied, controlled for many important variables, for example, sociodemographic background variables, school characteristics, and family social capital. Results indicate that only the average GPA (grade point average) of peers had a consistent and significant effect on children's achievement and attainment, whereas the density and the homogeneity of the peer network did not. Furthermore, all three measures of peer social capital have stronger effects for immigrant youths than for native youths.     

Identity Crisis and Postcommunist Psychology

This article examines the effect that the recent changes in Soviet Society have had on the self-identity of its members. The sudden collapse of the Soviet Union and the precipitous decline of its economy deprived individuals of the familiar guideposts that served to define their identity. The void created in the self-consciousness of ex-Soviet citizens is now being filled by nationalist ideologies which emphasize ethnic exclusiveness and suppress the universalistic identity references typical of the modern era. The argument is made that the habitual self formed during the Soviet era offers a strong resistance to change and poses serious problems for Russian reformers.     

Robust median estimator in logistic regression

This paper introduces a median estimator of the logistic regression parameters. It is defined as the classical _L1$L_1$-estimator applied to continuous data _Z1,…,_Zn$Z_1,\dots ,Z_n$ obtained by a statistical smoothing of the original binary logistic regression observations _Y1,…,_Yn$Y_1,\dots ,Y_n$. Consistency and asymptotic normality of this estimator are proved. A method called enhancement is introduced which in some cases increases the efficiency of this estimator. Sensitivity to contaminations and leverage points is studied by simulations and compared in this manner with the sensitivity of some robust estimators previously introduced to the logistic regression. The new estimator appears to be more robust for larger sample sizes and higher levels of contamination.     

Locus of control and race track betting behaviors: A preliminary investigation

Principal components factor analysis of a fifteen-item betting behavior question-naire and the internal-external locus of control scale administered to 175 male racegoers at two different race tracks yielded four interpretable behavior patterns approximating four personality dimensions found in the gambling literature.     

Site-Specific Applications of Probabilistic Health Risk Assessment: Review of the Literature Since 2000

Whether and to what extent contaminated sites harm ecologic and human health are topics of considerable interest, but also considerable uncertainty. Several federal and state agencies have approved the use of some or many aspects of probabilistic risk assessment (PRA), but its site-specific application has often been limited to high-profile sites and large projects. Nonetheless, times are changing: newly developed software tools, and recent federal and state guidance documents formalizing PRA procedures, now make PRA a readily available method of analysis for even small-scale projects. This article presents and discusses a broad review of PRA literature published since 2000.     

Colorism and School-to-Work and School-to-College Transitions of African American Adolescents

Using multinomial logistic modeling, the current study estimated the impact of skin tone on school-to-work and school-to-college transitions of African American youths. The findings suggest that African American males with the lightest skin tone were more likely to find a job and to be in college than their co-racial peers with darker skin tones. The odds of finding a full-time job were also significantly higher for African American females with the lightest skin tone. Generally, the multivariate results reveal that among the effects examined in this study, the family background factors, marital status, prior achievement, and average school socioeconomic status matter the most.