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81.
In the past few years, the field of dam safety has approached risk informed methodologies throughout the world and several methodologies and programs are appearing to aid in the systematization of the calculations. The most common way of implementing these calculations is through the use of event trees, computing event probabilities, and incremental consequences. This methodology is flexible enough for several situations, but its generalization to the case of systems of several dams is complex and its implementation in a completely general calculation methodology presents some problems. Retaining the event tree framework, a new methodology is proposed to calculate incremental risks. The main advantage of this proposed methodology is the ease with which it can be applied to systems of several dams: with a single risk model that describes the complete system and with a single calculation the incremental risks of the system can be obtained, being able to allocate the risk of each dam and of each failure mode. The article shows how both methodologies are equivalent and also applies them to a case study.  相似文献   
82.
Two different theories, called bottom-up and top-down, were developed to understand the determinants of an individual's satisfaction. Experimental studies didn't provide unanimous results, and confirmed, to different extents, both theories. Aside from these classic theories, a constructionist approach was developed. The purposes of this study were to examine the top-down/bottom-up controversy from a constructionist point of view and to obtain a new method for measuring the top-down effects in different satisfaction judgements. In this approach, an individual's satisfaction is viewed as constructions, evoked by the specific question in its particular context, and made by people using cognitive strategies. This view implies that the correlation between satisfaction judgements may reflect the use of the same strategies, rather than a causal effect. From this point of view, the top-down and bottom-up effects, described by the classic theories, cannot be seen as a pattern of causal links among satisfaction domains; therefore we propose a reinterpretation of these concepts in which they refer to ways used by people to construct their satisfaction judgements. On these grounds, we developed a method to extract the weight of top-down effects from correlation coefficients between satisfaction judgements. Two hypotheses concerning the different weight of top-down processes in the different satisfaction judgements were subsequently developed.These propositions were tested using the data set of 'Outdoor Mobility Survey' which was carried out in Italy on a sample of 600 people, 55--95 years of age, stratified by sex and age. We found different top-down effects in satisfaction judgements that confirm our hypothesis, even if some aspects need further investigation.  相似文献   
83.
This paper describes the results of a self‐reporting dairy completed by 186 male sex workers (MSWs) over a 2‐week period in Brisbane, Sydney, and Melbourne, Australia. The diary was completed following each commercial sex encounter by the MSW. The results reveal that MSWs reported 2088 commercial sex encounters during the study period, with an average of 11.2 encounters per MSW. The majority of sex encounters took place in either the client's or the MSW's residence, with significant variations by city. The average sexual encounter lasted 70 minutes, and comprised two sexual acts, masturbation and oral sex. Condom use was reported in 67.4% of all the encounters. Using the AIDS Council safe‐sex classification system, the majority of the commercial sex encounters fell in the “safer sex” category; however, there were significant differences by source of clients and place of the encounter. Use of drugs and alcohol reveal interesting patterns: Clients were more likely to use alcohol, while MSWs had significant differences of usage of the different drugs. This study demonstrates that the majority of MSWs are offering and practicing safe sex behaviours, however, MSWs working in the street setting are still likely to be practising unsafe sex. Male sex work is becoming an organised business and this provides opportunities to implement further public health interventions.  相似文献   
84.
In this paper we obtain several influence measures for the multivariate linear general model through the approach proposed by Muñoz-Pichardo et al. (1995), which is based on the concept of conditional bias. An interesting charasteristic of this approach is that it does not require any distributional hypothesis. Appling the obtained results to the multivariate regression model, we obtain some measures proposed by other authors. Nevertheless, on the results obtained in this paper, we emphasize two aspects. First, they provide a theoretical foundation for measures proposed by other authors for the mul¬tivariate regression model. Second, they can be applied to any linear model that can be formulated as a particular case of the multivariate linear general model. In particular, we carry out an application to the multivariate analysis of covariance.  相似文献   
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We employ a discretetime hazard model and a Blinder-decomposition approach to explore the possibility of racial discrimination in the dismissal and retention of college football coaches by university administrations. A rich data set consisting of 81 institutions over an 11-year period (1990–2000) that contains, in addition to a coach's race, variables on cumulative winning records, annual on-the-field improvements, and pre-/post-season game participation by institutions and their coaches is employed. Our study finds that black coaches, on average, face a dismissal probability that is 9.6 percentage points below that of their nonblack counterparts, ceteris paribus, suggesting that black head coaches may be the beneficiaries of favorable treatment by university administrators. Such a result likely stems from universities ' approach to social concerns involving race and gender issues. This finding also fits a construct that considers workplace discrimination as multi-dimensional. For example, black representation in the college football coaching ranks may be disproportionately low, possibly as a result of discrimination. However, once hired, black coaches are given more time to succeed than nonblacks, other things constant.  相似文献   
88.
Extensive mobility between class of origin and class of destination has been a characteristic feature of societies in Europe and North America since the middle of the twentieth century. Most mobility has been upward, and most of that has been explicable by occupational change – by the rise in the proportion of the labour force which works in service‐class jobs and the decline in the proportion in manual jobs. This pattern may now be changing, because parents of younger cohorts (people born since the 1960s) have themselves benefited from upward mobility and so there is less scope for further upward movement by their offspring. The paper uses a large new data source for Scotland to investigate these topics. It finds that there is still a great deal of mobility, and that, although upward mobility still predominates, its amount is lower in younger cohorts than in older. Nevertheless, relative mobility has not changed as upward mobility has declined, just as in earlier studies it was found not to have changed as upward mobility rose. These patterns are similar for men and women.  相似文献   
89.
This article examines the interrelations between establishment of territorial quality certification systems (Protected Designations of Origin or PDOs), diffusion of innovations through local agro-food chains, and the role of the institutions overseeing geographical designations. Empirical analysis is applied to olive oil PDOs in Spain and entails a detailed case study of the “Sierra Mágina” PDO in Andalusia. Making use of the neoinstitutional concept of ‘organised proximity’—and focussing specifically on the problematic of organizational quality—the article assesses characteristics that support the competitive positions of local certified-product production systems. In particular, the authors find that collective organisation and coordination between PDO agents who are locally responsible for quality assurance and protection can enhance local competitiveness. Three hypotheses are confirmed. First, PDO labels can, through the action of PDO regulators, become quality assurance systems for distributors. Second, PDO Regulatory Boards can enhance and coordinate local inter-professional activities, particularly with respect to the diffusion of quality-enhancing innovations and knowledge. Third, the study indicates that local certified-product systems are starting to incorporate quality attributes linked to the environment and sustainable development, although much remains to be accomplished in this regard.  相似文献   
90.
Females live longer than males in many species, including humans. We have traced a possible explanation for this phenomenon to the beneficial action of estrogens, which bind to estrogen receptors and increase the expression of longevity-associated genes, including those encoding the antioxidant enzymes superoxide dismutase and glutathione peroxidase. As a result, mitochondria from females produce fewer reactive oxygen species than those from males. Administering estrogens has serious drawbacks, however--they are feminizing (and thus cannot be administered to males) and may increase the incidence of serious diseases such as uterine cancer in postmenopausal women. Phytoestrogens, which are present in soy or wine, may have some of the favorable effects of estrogens without their undesirable effects. Study of gender differences in longevity may help us to understand the basic processes of aging and to devise practical strategies to increase the longevity of both females and males.  相似文献   
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