A comparative study of the searching efficiencies of a parasite and a hyperparasite

Summary The searching efficiencies of a primary parasite (Diaeretiella rapae (McIntosh)) and a hyperparasite (Alloxysta brassicae (Ash.)) were investigated and compared. In both species, at all parasite densities, there was a curvilinear relationship (P<0.001) between the number of hosts parasitised and the host density. A linear regression (loga=logQ−m logP) was fitted for log area of discovery against log parasite density (P<0.001). The area of discovery for its immediate (i.e. primary) host (viz.Diaeretiella for the hyperparasite and aphid forDiaeretiella) is lower in the hyperparasite than in the primary parasite. InDiaeretialla both the searching efficiency and the mutual interference constant increased (but not significantly,P>0.05) in the presence of its males.     

Social Fathers and Child Well‐Being

Many young children born to unwed parents currently live with their biological mothers and their mothers’ new partners (social fathers). This study uses data from the Fragile Families and Child Well‐Being Study (N = 1,350) to assess whether involvement by resident social fathers is as beneficial for child well‐being as involvement by resident biological fathers and whether the involvement of the child’s nonresident biological father alters the relationship between resident social father engagement and child outcomes. Results indicate that involvement by resident social fathers is as beneficial for child well‐being as involvement by resident biological fathers and that frequent contact with the child’s nonresident biological father does not diminish the positive association between residential social father involvement and child well‐being.     

A study of BIB designs through support matrices

This paper deals with the existence and nonexistence of BIB designs with repeated blocks. The approach is an algebraic one. The concept of a support matrix is introduced and some of its basic properties are noted. Some basic examples of support matrices are given when the block size is 3. The connection between full column rank proper support matrices and irreducible designs is explored and some examples of such matrices are given.     

A Longitudinal Study of Depressive Symptoms and Marijuana Use in a Sample of Inner‐City African Americans

The association between marijuana use and depressive symptoms was examined longitudinally in a sample of 622 African American youth, interviewed on six occasions, using hierarchical linear modeling (HLM). We considered whether depressive symptoms predicted changes in marijuana use and vice versa from high school through the transition into young adulthood. We also examined gender differences in these behaviors over time. The results indicated that depressive symptoms predicted later marijuana use only for males. Marijuana use did not predict later depressive symptoms for females or males. These findings are consistent with a unidirectional hypothesis indicating that marijuana use may play a role as mood regulator among young males, but not among females. Research findings also indicate that females with lower depressive symptoms use more marijuana than females who report high depressive symptoms. These findings did not change even after controlling for the effects of using other substances at previous stages, school achievement, and demographics factors. These results suggest that depressive symptoms may be an antecedent of marijuana use among African American males.     

Serial dependence and regression of Poisson INARMA models

Time series of counts occur in many fields of practice, with the Poisson distribution as a popular choice for the marginal process distribution. A great variety of serial dependence structures of stationary count processes can be modelled by the INARMA family. In this article, we propose a new approach to the INMA(q) family in general, including previously known results as special cases. In the particular case of Poisson marginals, we will derive new results concerning regression properties and the serial dependence structure of INAR(1) and INMA(q) models. Finally, we present explicit expressions for the distribution of jumps in such processes.     

Is rational choice humanity’s most distinctive trait?

The Greeks and the thinkers of the Enlightenment regarded reason as the defining quality of humankind. The Utilitarians limited it to the selection of means to any given end for action excluding the determination of moral values and social institutions. This became a postulate of classical and neoclassical economics borrowed by rational choice theory in sociology. James Coleman accepted as rational any action based on the actor's belief in its rationality, which would not rule out the delusions of psychotics. Despite this and other concessions that treat almost any explicable action as rational, sociologists have correctly criticized rational choice theory for ignoring the pervasive effects of socialization in achieving the internalization of norms and values. Rational choice theory also fails to illuminate human emotions and motivations, pictured in their full complexity in great literature.     

Two-Event Model for Carcinogenesis: Biological, Mathematical, and Statistical Considerations

A two-mutation model for carcinogenesis is reviewed. General principles in fitting the model to epidemiologic and experimental data are discussed, and some examples are given. A general solution to the model with time-dependent parameters is developed, and its use is illustrated by application to data from an experiment in which rats exposed to radon developed lung tumors.     

Michael Polanyi and the sociology of a free society

Michael Polanyi’s defense of freedom in science and society conflicts in major ways with Weber (process of rationalization, value neutrality of sociologists), Popper (objective knowledge, open society), and technological or oppositional sociology. Polanyi rejects positivism, utilitarianism, and Marxism, and defends freedom as a necessary condition for pursuit of spiritual ideals such as truth, justice, charity, and tolerance. Half truths about science seen as rejecting tradition, faith, authority, values, and the subjective, have helped bring valuable social results, but in the form taken by radical philosophical skepticism (doubt), also called objectivism, they also threaten freedom itself. A more truthful account is needed. Scientists and citizens who would maintain a free society are morally responsible persons, joined together in quest of truth and certain other ideals, demanding of themselves and each other that they be faithful to that quest. Polanyi’s thought has connections with that of Shils, and has implications for what Shils calls a consensual sociology. Louis H. Swartz teaches law, and is interested in the development of sociological theory and legal sociology, building upon the contributions of Polanyi and Shils.