America's baby boom generation: the fateful bulge

From 1955-64 nearly 42 million births occurred in the U.S., an unprecedented expansion. The roots of the baby boom lie in the universal rush to early marriage and favorable economic climate for the relatively scarce young men born of the Depression cohort. The impact of the boom interrupted a century-long fertility decline. Pro-marriage, pronatalist norms were revived by the Depression cohort who formed families of at least 2 children or more. During the 1960-70's schools, colleges, and universities were built to accomodate the boom and are now excessive for the baby bust cohort. Unemployment and crime rates rose and fell with the passing of the boom babies through late adolescence and early adulthood. In the 1980's, boom babies will be aged 20-30. Demands for housing will be high. Annual birth numbers will increase even if the rate of childbearing hovers below replacement level at about 1.8 per woman. Per capita earnings and overall labor productivity should improve as the boom baby cohort reaches middle age in the 1990s. However, chances for advancement will be fewer. As the cohort reaches retirement age, the over 65 population will double from 31 million in 2000 to almost 60 million in 2030. Although the burden will be somewhat offset by reduced proportions of under 18-year-olds, the ratio of active workers paying Social Security will fall drastically.     

Quality of the urban environment as perceived by residents of slow and fast growth cities

Through the vehicle of the Winnipeg and Edmonton Area Surveys of 1981 this paper compares perceptions of the city by its residents in two cities of dramatically different growth rates, holding constant the region of the country, the size of the city, the time of the analysis and the methodology used. The growth rate did influence the evaluations of the attributes of the city by its residents. However, this evaluation of growth was not a significant contributer to overall satisfaction with the city. While levels of satisfaction with the city were similar in the two cities, the contributing variables differed somewhat.     

U.S. population in the 21st century: Which scenario is reasonable?

A major Census Bureau study released in January 1989 has evoked renewed warnings in the media and among some population analysts that the U.S. faces population decline in the next century if it does not increase fertility and/or raise immigration. The report's middle scenario rests on an assumed future total fertility rate (TFR) of 1.8, life expectancy of 81.2 years, and net immigration of 500,000 annually. These mid-range assumptions would yield a United States population of 268 million by 2000, peaking at 302 million in 2040 and falling to 292 million by 2080. Questionable assumptions in the report's most likely scenario are discussed. These are:

1. that immigrants bear children at the same rate as their equivalent age and racial group in the United States population.
2. that the high TFR of Hispanics will not raise the overall 1.8 TFR foreseen for whites as the Hispanic proportion of the white population continues to grow.
3. that net yearly immigration will fall to 575,000 in 1990 and 500,000 by 2000. The Census Bureau's "high" assumption of 800,000 net yearly may be more realistic.

The report's low growth scenario projects future population size that is more reassuring than alarming: 264 million in 2000, rising to 288 million in 2030, and falling to 266 million in 2080. Thus, in ninety years the United States would still have 20 million more people than now. While some fear that such slow growth will lower United States influence and bring labor shortages and an aging population, the nation's quality of life would be less at risk with a population of 266 million than with one approaching the one-half billion projected by the Census report's high estimates.     

Overwintering ecology of two social halictine bees,Lasioglossum duplex andL. problematicum

Summary Overwintering of two social halictine bees,Lasioglossum duplex (Dalla Torre) andL. problematicum (Blüthgen), was studied. InL. duplex many females stay near the old nests, each female preparing a hibernaculum separated from the natal nest. InL. problematicum most females overwinter communally within the natal nest. This difference in overwintering habits relates to the social structure in the next spring.L. duplex is nearly always solitary in spring although later becoming eusocial, whereas many nests ofL. problematicum are polygynous, beginning in early spring.L. duplex overwinters much deeper ( ) in the soil than doesL. problematicum ( ), but both species are safe from drops in soil temperature, which is above 0°C even in midwinter, and the bees' supercooling points are lower than −6°C. This cold resistance and the storage of sufficient food in the crop are reflected in the winter survival, which is much higher (79%) than the rate of successful nests in the spring active phase (25%). Bionomics of the eusocial halictine beeLasioglossum duplex VII. Contribution No. 2654 from the Inst. Low Temp. Sci.