Dynamics ofSitotroga cerealella (olivier) (lepidoptera: gelechiidae) andSitophilus zeamais motschulsky (Coleoptera: Curculionidae) populations in a small bulk of stored corn

Summary The dynamics of Angoumois grain moth,Sitotroga cerealella (Olivier), and maize weevil,Sitophilus zeamais Motschulsky, populations breeding in a small bulk (initially 5.36 t) of shelled corn were studied over an 8-year period by monthly sampling. The weevil population showed wide fluctuations in density superimposed on a general decline with time. The moth population showed no upward or downward trend for the first 60 months, although it fluctuated widely. Following a decline that occurred between 56 and 60 months, the moth population fluctuated within a much narrower range, and there was a general decrease in density with time. The decline of the weevil population paralleled deterioration of the corn as did that of the moth population after ca 60 months, and the decline of both species probably resulted from increasing scarcity of suitable breeding sites. Both populations exhibited seasonal variation in density with minima in late summer and early fall, following periods of adversely high temperatures in the storage shed. The populations increased during the fall, leveled off or declined slightly during the winter months, and then increased to maximum levels in late spring or early summer. It thus appears that high temperatures had a greater adverse effect on the populations than low temperatures. The grain moth and the maize weevil both tended to be randomly dispersed at low population levels and moderately aggregated at intermediate and high levels, although the degree of aggregation was not correlated with population density when low population levels were considered separately, and the maize weevil showed a greater tendency for aggregation than did the grain moth. Analysis of individual samples at fixed points in time showed a conspicuous bias for negative correlation between numbers of the two species within sampling quadrats, suggesting a tendency for the two species to segregate within the grain mass. This process could have resulted from behavioral differences or from the destruction of one species by the other. Competitive displacement of the grain moth by the maize weevil has been demonstrated in laboratory experiments but has rarely been observed under natural conditions, and in our study the two species coexisted for 8 years in a relatively small grain bulk.     

Impact of developmental variance on behavior of models for insect populations II. Models for populations with density dependent restrictions on growth

Summary The impact of variation in developmental times on behavior of models for insect populations is investigated with special reference to models which include various types of intraspecific competition. At low densities, increases in developmental variation led to decreases in reproductive rate. At high densities, increases in developmental variation led to increases in reproductive rate. There was little change in the relationship between developmental variance and generation time as density increased.     

Heterosexual bias in psychological research on lesbianism and male homosexuality (1979-1983), utilizing the bibliographic and taxonomic system of Morin (1977)

Utilizing the concept of heterosexual bias, recent research on homosexuality is evaluated to see if this bias has lessened in recent years. In 1977 the suggestion was made that a new vision of homosexuality as an alternate and equally valid lifestyle would result in changes in the questions posed, the data collected, and the interpretations made in research on homosexuality. Recent journal article abstracts are examined and weighed to find the extend to which they reflect a change in the social values of the behavior under study. These findings are compared to those of the original study in 1977 and assessed to see if the predicted changes have come about. Strong evidence of such a change was found.     

The influence of catholic schools on the desegregation of public school systems: A case study of white flight in Boston

White flight from public school desegregation can result in educational and residential resegregation which defeat the purpose of desegregation programs. One form of white flight is pupil transfer to private schools, which in major metropolitan areas are predominantly Catholic schools. Unlike residential relocation, transfers to Catholic schools do not effect an increase in residential segregation and they constitute a potentially less permanent loss to the public system than that caused by relocation. Nevertheless, empty seats in area Catholic schools pose a threat to the success of any desegregation program. For the Catholic diocese, the white flight issue creates a complex conflict of interests, involving institutional self-interest and competing claims to moral principles and Church teachings.A case study of Boston indicates that approximately 2,000 students transferred to Catholic schools from the public system, accounting for over 20 percent of white pupil loss to the public system. This occurred despite diocesan policies designed to prevent white flight to Catholic schools. An analysis of political and institutional constraints on policy development and implementation provides a basis for predicting Church response to future desegregation programs in other locations. Suggestions for diocesan programs designed to address desegregation issues are included.This research was conducted as part of a national study of public school desegregation directed by Karl E. Taeuber. Funding was provided by the Institute for Research on Poverty and the Wisconsin Center for Educational Research, both at the University of Wisconsin at Madison. I wish to thank Dr. Taeuber for facilitating this particular study and for helpful comments on an earlier draft. I also wish to acknowledge the valuable assistance of Mary J. McDonald and Roger Hedge of the Massachusetts Department of Education and Rev. Eugene Sullivan, Superintendent of Schools of the Archdiocese of Boston. Conclusions and interpretations presented here are the sole responsibility of the author.     

Comrade Mao Ze-dong's contribution to Marxist theory on population--in commemoration of the 60th anniversary of the birth of the Chinese Communist Party]

Is it good or bad to have a large population in China? Comrade Mao Ze-dong said "it is good and it is also bad." Our population is an asset, and we should use this asset and wisdom in our nation's "Four Modernizations" program. On the other hand we should control the population growth and reduce the resulting burden. Marxism recognizes 2 types of production, material production and human production. Both are interrelated, mutually dependent, and beneficial. Comrade Mao criticized concepts and practices that disregard the interrelationship of these 2 types of production. According to Comrade Mao both types of production should be included in the national economic plan, and the proportions of material production and human production should be the basic proportions of our socialistic economic development. Comrade Mao mentioned that population growth should be planned to fit and benefit social development. He suggested establishment of a series of family planning offices or committees to study and implement the family planning program, to develop a longterm plan, to consider the people's wishes in family planning, to meet the people's requirements and desires, to educate people about family planning, and to recommend government funds for the program.     

Changes in wealth in the United States, 1962–1983

A simulation model is developed to account for observed changes in mean household wealth both overall and by age cohort over the 1962–1983 period in the United States. There are three major findings. First, capital gains are the major factor explaining overall wealth changes and account for 77% of the simulated growth in wealth over the entire period. Second, for cohorts under age 40, inheritance and inter vivos transfers dominate observed changes in wealth. Indeed, the oldest age groups appear to have transferred sizable amounts of their wealth to younger generations inter vivos, raising the wealth of these younger groups substantially above what it would be based on saving. Third, while differences in portfolio composition favored the younger cohorts over this period, such differences do not explain a large portion of the great variation in real wealth changes by cohort over the two decade period.The authors wish to thank Kevin Camerlo, Maury Gittleman and Kim Hiskey for research and programming assistance.     

Cohort effects in the educational attainment of second generation immigrants in Germany: An analysis of census data

Even though second generation immigrants make up ever increasing population shares in industrialized countries we know little about their social integration and wellbeing. This study focuses on the educational attainment of German born children of immigrants. Their schooling success still lags behind that of natives. This paper investigates school attendance and completed degrees of second generation immigrants and finds that even after controlling for characteristics the educational gap remains large and significant. The available evidence suggests that this group as a whole does not assimilate to native educational standards and instead increasingly falls behind.This research was completed while the author was guest at the Institute for the Study of Labor (IZA) in Bonn, Germany. I am grateful for IZAs hospitality and particularly for the help of Thomas K. Bauer. I thank the anonymous referees and the editors for very helpful comments. Responsible editors: David Card and Christoph M. Schmidt.