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981.
Statistical expert systems: necessary attributes   总被引:1,自引:1,他引:0  
  相似文献   
982.
This article offers an alternative view on the emergence of new forms of development co‐operation by analysing the emergence of SWAps in Zambia since the early 1990s. SWAps in Zambia emerged not as part of a grand design but in response to the changing environment in which aid agencies were operating. An examination of the relative success of the health and education SWAps and the spectacular failure of the agriculture SWAp suggests that a flexible approach is more effective than the imposition of a planning template. Furthermore, the failure of the agricultural SWAp has been followed by significant new forms of public/private partnership.  相似文献   
983.
We examine methods for reducing respondent burden in evaluating alter–alter ties on a set of network structural measures. The data consist of two sets, each containing 45 alters from respondent free lists: the first contains 447 personal networks, and the second 554. Respondents evaluated the communication between 990 alter pairs. The methods were (1) dropping alters from the end of the free-list, (2) randomly dropping alters, (3) randomly dropping links, and (4) predicting ties based on transitivity. For some measures network structure is captured with samples of less than 20 alters; other measures are less consistent. Researchers should be aware of the need to sample a minimum number of alters to capture structural variation.  相似文献   
984.
The life orientation test-revised (LOT-R) (Scheier et al. in Journal of Personality and Social Psychology 67:1063–1078, 1994) is a brief measure for assessing dispositional optimism. The aim of this study was to develop a Greek language version of the LOT-R and to assess the instrument’s psychometric properties. The LOT-R was translated and culturally adopted in Greek language, and the final version was administered, along with a questionnaire consisting socioeconomic characteristics and a single item measuring optimism, to 276 Greek speaking, hospital nurses (222 female, 54 male), aged 22–65 years (mean 37.8, SD 8.3). Results showed that the LOT-R has good internal consistency (Cronbach’s α = .71 and item total correlation coefficients from .27 to .73, a unitary structure, and stability over a 3-months period (r = .66). Moreover, the Greek version of the scale exhibited good convergent validity with single-item optimism scale (r = .73). Principal components analysis revealed a two-factor structure representing the constructs of optimism and pessimism. The Greek life orientation test revised appears to be a valid tool in assessing dispositional optimism in Greek speaking people and is expected to facilitate the examination of optimism in Greek speaking populations.  相似文献   
985.
Contrary to Bourdieu’s theory (Distinction: A social critique of the judgment of taste. Cambridge, Massachusetts: Harvard University Press (1984)) that cultural consumption of so-called “high” versus popular culture is determined by socio-economic class, Peterson (Poetics 21:243–258, 1992; Poetics 33:257–282, 2005) finds that higher income and education groups are more likely to be “cultural omnivores”—consumers of a wide variety of both high and popular cultural goods. Omnivores were also found to be much less likely to exclude other cultures and to be more open to, and tolerant of, the views of others than those with narrower cultural tastes, called “cultural univores”. This article investigates the omnivore/univore hypothesis in a South African context, using survey data collected from 500 attendees of live theatre performances at the National Arts Festival in 2008. Multiple correspondence analysis (also called perceptual mapping) shows an interesting intermediate state between Boudieu-like high culture univores and Peterson omnivores, which could have interesting implications for the development of social tolerance in multi-cultural South Africa.  相似文献   
986.
Belgium's systems of unemployment insurance and employment protection legislation were set up in the context of typically enduring and stable relationships between workers and firms. Economic globalization and rapid technological and organizational change, however, are now demanding more flexibility of both workers and firms. As a result, current labour market institutions are in urgent need of reform to reconcile such increased flexibility with adequate security for workers. Though the call for a “flexicurity” approach is not new, there is no single view of what institutional model the latter implies. This paper proposes a reform explicitly guided by economic principles.  相似文献   
987.
The area under the receiver operating characteristic curve (AUC) is the most commonly reported measure of discrimination for prediction models with binary outcomes. However, recently it has been criticized for its inability to increase when important risk factors are added to a baseline model with good discrimination. This has led to the claim that the reliance on the AUC as a measure of discrimination may miss important improvements in clinical performance of risk prediction rules derived from a baseline model. In this paper we investigate this claim by relating the AUC to measures of clinical performance based on sensitivity and specificity under the assumption of multivariate normality. The behavior of the AUC is contrasted with that of discrimination slope. We show that unless rules with very good specificity are desired, the change in the AUC does an adequate job as a predictor of the change in measures of clinical performance. However, stronger or more numerous predictors are needed to achieve the same increment in the AUC for baseline models with good versus poor discrimination. When excellent specificity is desired, our results suggest that the discrimination slope might be a better measure of model improvement than AUC. The theoretical results are illustrated using a Framingham Heart Study example of a model for predicting the 10-year incidence of atrial fibrillation.  相似文献   
988.
The problem of calculating approximate confidence limits for the difference between success probability parameters of two Pólya distributions is solved for the first time. We suggest some new methods for determining these approximate confidence limits and consider their application to special cases: namely for the binomial and hypergeometric distributions. The various approximate confidence limits are evaluated and compared.  相似文献   
989.
The purpose of this study was to examine the influence of peer modeling on sexually impositional behavior in the laboratory. Male participants with and without a self‐reported history of sexually aggressive behavior viewed video clips depicting nonaggressive and sexually aggressive behavior and then chose one of the clips to show to a female confederate. Half of the participants were first exposed to a male confederate who showed the sexually aggressive video clip to a female confederate. The other half of the participants were exposed to a male confederate who showed a nonaggressive video clip to a female confederate. Exposure to a male confederate who showed a sexually aggressive video clip to a female was associated with participants' choosing to engage in this same behavior. A self‐reported history of sexually aggressive behavior was also associated with participants' showing the sexually aggressive video clip in spite of believing the effect on the female viewer would be negative.  相似文献   
990.
The analysis of the spread of HIV in homosexual populations must be based on knowledge of all factors which promote or inhibit transmission. Recently, data were reported from the Amsterdam cohort study that imply that sexual role separation and the changes therein should be taken into account in analyzing and modeling the spread of HIV. In this paper, a role separation mixing model is described and linked to data from the Amsterdam cohort. The model allows one to study the impact of homosexual role separation on the spread of HIV. The homosexual men are classified into four sexual subgroups based on the preference for: 1) no anal intercourse; 2) anal insertive only; 3) anal receptive only; 4) both insertive and receptive. The analysis accounts for variability and change in homosexual role behavior and loss to follow up. The results support the conjecture that there are large differences between the risks of receptive and insertive anal intercourse, with the latter carrying only minimal risk. The analysis indicates that the spread of HIV is mostly restricted to subgroup 4, the largest and sexually most active subgroup. In this subgroup, the estimated probability of HIV transmission from an infected insertive partner (in subgroup 2 or 4) to a receptive susceptible (in subgroup 4) is between 1 and 5 percent (assuming a closed cohort).  相似文献   
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