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901.
Since children, particularly daughters, are among the most important sources of help and support for older Americans, it has been suggested that women's increasing employment will affect filial relations. Empirical evidence on this issue is inconsistent, in part due to the use of nonprobability samples. Few studies have measured effects for men. We attempt to broaden the scope of this question beyond help to the frail elderly by asking whether employment affects filial relations in general. We examine effects of hours employed on telephone contact, visiting, feelings of closeness, filial attitudes, and assistance to biological parents, for an area probability sample of men and women over 40. There are no effects of employment for men or women on contact, closeness, or assistance. For the vast majority of this population sample, contact and assistance involve few hours per week, and thus do not seem to conflict with employment. 相似文献
902.
903.
904.
Journal of Management and Governance - 相似文献
905.
Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter
has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health
at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions
were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the
tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster
based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels
within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against
a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy.
At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers
to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease
and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling
and analysis of the environmental, social, and economic services produced by urban forests. 相似文献
906.
907.
Peter B. Gilbert 《Journal of the Royal Statistical Society. Series C, Applied statistics》2005,54(1):143-158
Summary. To help to design vaccines for acquired immune deficiency syndrome that protect broadly against many genetic variants of the human immunodeficiency virus, the mutation rates at 118 positions in HIV amino-acid sequences of subtype C versus those of subtype B were compared. The false discovery rate (FDR) multiple-comparisons procedure can be used to determine statistical significance. When the test statistics have discrete distributions, the FDR procedure can be made more powerful by a simple modification. The paper develops a modified FDR procedure for discrete data and applies it to the human immunodeficiency virus data. The new procedure detects 15 positions with significantly different mutation rates compared with 11 that are detected by the original FDR method. Simulations delineate conditions under which the modified FDR procedure confers large gains in power over the original technique. In general FDR adjustment methods can be improved for discrete data by incorporating the modification proposed. 相似文献
908.
Armand J. Thieblot 《Journal of Labor Research》2005,26(1):99-134
Each individual wage rate set by Davis-Bacon or by any similar state or local prevailing wage determination petrifies the
outcome of competing views of how construction work should be staffed and paid on public works projects. Although presented
with great precision (to tenths of a cent for both wages and fringe benefits), the level of wages themselves are of surprisingly
little consequence: Those set at union levels soon rise, being automatically updated to new contracts and conditions; the
rest fast become obsolete in any rising market, because surveys to update them are rare. But in addition to setting wage levels,
determinations also delineate which jobs get to have rates set for them, and perhaps most critically, whether those delineated
are identified as union or notunion. Whatever pattern is found may remain in effect for years or even decades, influencing
which journeymen and laborers own what job tasks and who may perform what. Also, if a particular job happens to be set as
union, it may bring with it dozens or even hundreds of related special job categories, grades of sub-groups, fine distinctions
of fringe benefits, and complex divisions of geographic applicability based on local union jurisdictional areas. This study
uses determinations recently made in Pennsylvania as an example to examine the mechanics of the wage-setting process. I find
that, in addition to the endemic problems one might expect associated with a complex and partly judgmental process, every
step of finding and setting prevailing rates includes overwhelming deference on the part of government towards union views
and methods. It shows why unions representing less than 20 percent of the private construction work force consistently set
the parameters controlling most of public construction. It ends with some suggestions on how better surveys and determinations
could be made. 相似文献
909.
Bhaswati Ganguli John Staudenmayer M.P. Wand 《Australian & New Zealand Journal of Statistics》2005,47(2):193-202
This paper develops a likelihood‐based method for fitting additive models in the presence of measurement error. It formulates the additive model using the linear mixed model representation of penalized splines. In the presence of a structural measurement error model, the resulting likelihood involves intractable integrals, and a Monte Carlo expectation maximization strategy is developed for obtaining estimates. The method's performance is illustrated with a simulation study. 相似文献
910.
Anthony E. Ladd 《Sociological inquiry》1991,61(3):299-313
Despite sociopolitical controversy surrounding the solid waste crisis, little sociological attention has focused on this crucial environmental issue. Drawing on research from the technological controversies, environmental concern, and solid waste literatures, this study examines the pre-implementation anxieties of a Louisiana community faced with a proposal to build an incinerator in its backyard. Utilizing survey data, a causal path model is developed in which the perceived advantages of the technology, general environmental concern, and support for recycling initiatives are identified as explanatory variables of incinerator opposition. Implications of these findings for the study of technical controversies and the larger solid waste crisis also are suggested. 相似文献