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51.
We describe and illustrate methodology for comparing networks from diverse settings. Our empirical base consists of 42 networks from four kinds of species (humans, nonhuman primates, nonprimate mammals, and birds) and covering distinct types of relations such as influence, grooming, and agonistic encounters. The general problem is to determine whether networks are similarly structured despite their surface differences. The methodology we propose is generally applicable to the characterization and comparison of network–level social structures across multiple settings, such as different organizations, communities, or social groups, and to the examination of sources of variability in network structure. We first fit a p* model (Wasserman and Pattison 1996) to each network to obtain estimates for effects of six structural properties on the probability of the graph. We then calculate predicted tie probabilities for each network, using both its own parameter estimates and the estimates from every other network in the collection. Comparison is based on the similarity between sets of predicted tie probabilities. We then use correspondence analysis to represent the similarities among all 42 networks and interpret the resulting configuration using information about the species and relations involved. Results show that similarities among the networks are due more to the kind of relation than to the kind of animal.  相似文献   
52.
53.
Arrow's axioms for social welfare functions are shown to be inconsistent when the set of alternatives is the nonnegative orthant in a multidimensional Euclidean space and preferences are assumed to be either the set of analytic classical economic preferences or the set of Euclidean spatial preferences. When either of these preference domains is combined with an agenda domain consisting of compact sets with nonempty interiors, strengthened versions of the Arrovian social choice correspondence axioms are shown to be consistent. To help establish the economic possibility theorem, an ordinal version of the Analytic Continuation Principle is developed. Received: 4 July 2000/Accepted: 2 April 2001  相似文献   
54.
The extent of carcinogen regulation under existing U.S. environmental statutes is assessed by developing measures of the scope and stringency of regulation. While concern about cancer risk has played an important political role in obtaining support for pollution control programs, it has not provided the predominant rationale for most regulatory actions taken to date. Less than 20% of all standards established to limit concentrations of chemicals in various media address carcinogens. Restrictions on chemical use are more frequently based on concerns about noncancer human health or ecological effects. Of the chemicals in commercial use which have been identified as potential human carcinogens on the basis of rodent bioassays, only a small proportion are regulated. There is an inverse relationship between the scope of regulatory coverage and the stringency of regulatory requirements: the largest percentages of identified carcinogens are affected by the least stringent requirements, such as information disclosure. Standards based on de minimis cancer risk levels have been established for only 10% of identified carcinogens and are restricted to one medium: water. Complete bans on use have affected very few chemicals. The general role that carcinogenicity now plays in the regulatory process is not dramatically different from that of other adverse human health effects: if a substance is identified as a hazard, it may eventually be subject to economically achievable and technically feasible restrictions.  相似文献   
55.
In this paper, with the use of linear regressions to investigate how relationship dissolution affects sexual attitudes and behaviors, the authors address the stereotype that newly single people seek multiple sexual partners. Although the newly single people surveyed did obtain new sexual partners, the rate at which they acquired new partners did not support the stereotype. Specifically, men with custody of their children seemed oriented toward finding a steady partner. Additionally, men and women with low incomes reported relatively high rates of partner acquisition after relationship dissolution. The high rates reported by disadvantaged groups may be more directly related to familial instability accompanying poverty than to cultural characteristics associated with income or race. We argue that a life stage model with categorical stages in a rigid, anachronistic progression provides insufficient means to gain an understanding of newly single people.  相似文献   
56.
Extractive industries such as logging and mining are generally expected to bring significant economic benefits to rural regions, but a growing number of findings have now challenged that common expectation. Still, it is not clear whether the findings of less–than–desirable economic outcomes are isolated or representative. In this article, we assemble literally all of the relevant quantitative findings on mining that we have been able to identify in published and/or technical literature from the United States. In the interest of rigor, we limit the assessment to cases in which strictly nonmetropolitan mining regions are compared against other nonmetropolitan regions and/or against those regions’ own experiences over time. Overall, 301 findings meet the criteria for inclusion. Contrary to the long–established assumptions, but consistent with more recent critiques, roughly half of all published findings indicate negative economic outcomes in mining communities, with the remaining findings being split roughly evenly between favorable and neutral/indeterminate ones. Positive findings are more likely to be associated with incomes than with poverty or (especially) unemployment rates, and they are more likely to come from the western United States, where much of the mining involves relatively large, new coal strip mines. Over half of all positive findings come from the years prior to 1982. In virtually all other categories, the plurality or majority of findings have been negative. When the patterns of findings are subjected to one–sample means tests, the only way to produce a significantly positive outcome is by combining all neutral/indeterminate findings with the positive ones, while focusing exclusively on incomes; by contrast, in the case of poverty or unemployment rates—as well as for the overall body of findings—the results are consistently and significantly negative, whether the neutral/indeterminate findings are combined with negative ones or omitted from the equations altogether. Until or unless future studies produce dramatically different findings, there appears to be no scientific basis for accepting the widespread, “obvious” assumption that mining will lead to economic improvement.  相似文献   
57.
Many observers have noted that immigrants to the United States are highly concentrated in the largest metropolitan areas of a relatively few states. Though immigrants diffused into many places that had previously seen relatively few immigrants during the 1990s, as of the 2000 census, 77 percent of the nation's 31.1 million foreign born residents still lived in six states — California, New York, Texas, Florida, New Jersey, and Illinois. According to the 2000 census, the two largest metropolitan areas, Los Angeles and New York, accounted for one third of all immigrants ( http://www.census.gov/Press‐Release/www/2002/demoprofiles.html ). While immigrants moved into many new areas during the 1990s, making the challenge of incorporating their children a national issue, their concentration in our largest cities remained pronounced.  相似文献   
58.
This article seeks to define gender issues and explores the significance of these issues for challenging behaviour in the field of learning disability. It is argued that lack of awareness about these issues contributes to the development of challenging behaviour and to difficulties in identifying the needs expressed through these behaviours, whatever their origin. Specific areas examined include models of residential provision for adults, prioritisation of service activities, attribution processes (needs identification), and the sexuality of people with learning disabilities. In each area issues are raised and the implications for service practice defined.  相似文献   
59.
This paper describes the theoretical foundations, empirical findings, and practical and philosophical implications of the Boston Area Diary Study (BADS), a study of the caring behavior of 44 participants over one calendar year. In particular, the paper presents an identification theory of care and discusses how it shaped the conceptualization, collection, and analysis of the data in a year-long diary study of daily voluntary assistance. The findings from the BADS (1) theoretically confirm the identification theory of care; (2) methodologically capture how individuals perceive and carry out caring behavior as a unity; and (3rpar; empirically document the existence of a moral citizenship in America that is substantially more vigorous than is implied by the usual indicators of civic and political citizenship.  相似文献   
60.
This paper suggests a direction for the exploration of the causes of family violence. Explanatory models of family violence were considered in this regard, with the recommendation that a multi-determined model should be considered to ensure the most accurate explanation. We suggest that family violence will be best understood and prevented or alleviated, if a model is used that considers the interaction of structural violence and the personality features of all the family members.  相似文献   
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