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排序方式: 共有222条查询结果,搜索用时 171 毫秒
1.
This paper studies optimum designs for linear models when the errors are heteroscedastic. Sufficient conditions are given
in order to obtainD-, A- andE-optimum designs for a complete regression model from partial optimum designs for some sub-parameters. A result about optimality
for a complete model from the optimality for the submodels is included.
Supported by Junta de Andalucía, research group FQM244. 相似文献
2.
Recently, we developed a GIS-Integrated Integral Risk Index (IRI) to assess human health risks in areas with presence of environmental pollutants. Contaminants were previously ranked by applying a self-organizing map (SOM) to their characteristics of persistence, bioaccumulation, and toxicity in order to obtain the Hazard Index (HI). In the present study, the original IRI was substantially improved by allowing the entrance of probabilistic data. A neuroprobabilistic HI was developed by combining SOM and Monte Carlo analysis. In general terms, the deterministic and probabilistic HIs followed a similar pattern: polychlorinated biphenyls (PCBs) and light polycyclic aromatic hydrocarbons (PAHs) were the pollutants showing the highest and lowest values of HI, respectively. However, the bioaccumulation value of heavy metals notably increased after considering a probability density function to explain the bioaccumulation factor. To check its applicability, a case study was investigated. The probabilistic integral risk was calculated in the chemical/petrochemical industrial area of Tarragona (Catalonia, Spain), where an environmental program has been carried out since 2002. The risk change between 2002 and 2005 was evaluated on the basis of probabilistic data of the levels of various pollutants in soils. The results indicated that the risk of the chemicals under study did not follow a homogeneous tendency. However, the current levels of pollution do not mean a relevant source of health risks for the local population. Moreover, the neuroprobabilistic HI seems to be an adequate tool to be taken into account in risk assessment processes. 相似文献
3.
Sara Moreno-Colom Carolina Recio Càceres Teresa Torns Martín Vicent Borràs Català 《Journal of women & aging》2017,29(3):200-215
The aim of this article is to analyze the difficulties in professionalizing the long-term care system in Spain. Since 2006, the new Spanish law has recognized care as a subjective right, and regulations are being designed to create a framework for its professionalization. Nowadays, family remains the most important group of providers who care for their elders, and women remain the main informal caregivers. Why do families resist using public long-term care services and professional carers included in the new law? The hypothesis highlights sociocultural factors as an obstacle to professionalization of long-term care services in addition to political and economic factors. The results show qualitative data about expectations, preferences, and discourses that women caregivers have in relation to their responsibility. The empirical material includes 25 interviews with different profiles of caregivers and six focus groups with family caregivers. The article suggests that the Spanish ideal of care is a problem for the professionalization of services because the family remains as the main provider of care—without specific skills, knowledge, and abilities. 相似文献
4.
Nicolás Martínez Catalina Rubio Bañón Alicia Fernández Laviada Ana 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2019,30(3):443-459
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - A social business responds to social problems usually ignored by institutions, mobilizing resources and generating... 相似文献
5.
The aim of this paper is to obtain new sharp inequalities for a large family of topological indices, including the second variable Zagreb index \(M_2^{\alpha }\), and to characterize the set of extremal graphs with respect to them. Our main results provide lower bounds on this family of topological indices involving just the minimum and the maximum degree of the graph. These inequalities are new even for the Randi?, the second Zagreb and the modified Zagreb indices. 相似文献
6.
Carmen Martínez Novo 《Cultural Studies》2018,32(3):389-413
ABSTRACTThis article discusses two forms of discrimination against indigenous people: ventriloquism and open racism, and argues that a transition from paternalism to open intolerance has taken place in Ecuador in the context of governmental emphasis on natural resource extraction. Ventriloquism, when non-Indians speak for indigenous people, is analysed through the Sumak Kawsay (Good Living) policies of the government of Rafael Correa (2007–2017). Public racism is examined by looking at government repression against indigenous leaders and communities and Presidential speeches. The article concludes that the state’s ventriloquist and racist discourses and practices are equally rooted in the country’s colonial past. These findings are contrasted with the writings of scholars that have called the government of Mr. Correa decolonizing. The article examines the ways in which decolonial theorists informed and promoted the policies of this regime, and argues that decolonial scholars have been insufficiently self-critical and reflective of their own complicity with the state’s repressive project vis-à-vis indigenous communities. 相似文献
7.
8.
Ríos-Chelén Alejandro Ariel Cuatianquiz-Lima Cecilia Bautista Amando Martínez-Gómez Margarita 《Urban Ecosystems》2018,21(1):15-25
Urban Ecosystems - Vermilion flycatchers, a suboscine, sing songs with more elements in territories with higher urban noise levels. We tested the hypothesis that this pattern is achieved through... 相似文献
9.
In this paper, we present a multivariate version of the skewed log-Birnbaum–Saunders regression model. This new family of distributions holds good properties such as marginal variables following univariate skewed log-Birnbaum–Saunders distributions, besides presenting the usual log-Birnbaum–Saunders distribution as a particular case. Furthermore, the model parameters are estimated through maximum-likelihood methods, a closed-form expression for the Fisher’s information matrix is presented, and testing hypothesis for model parameters is performed. Two real datasets are analyzed and results are discussed. 相似文献
10.
Maider?Iglesias-CarrascoEmail author José?Martín Carlos?Cabido 《Urban Ecosystems》2017,20(6):1331-1338
Does urbanization affect key life-history traits in native organisms? Some studies show that urban areas reduce diversity in certain taxa, but there is little insight into how these environments affect physiological and ecological traits. Urban areas have distinct physical structure and ecological processes compared to original habitats. The environmental changes associated with urban areas can influence the costs and benefits of different traits and behaviors of local organisms. Some of these effects have been explored in groups such as birds, but we might expect stronger effects in animals with reduced mobility, such as amphibians. Importantly, the effects of urban habitats on amphibians have not been explored, in spite that these are the most threatened vertebrate group in the world. Here, we compared three main traits related to the fitness of amphibians in urban and natural habitats: body size, body condition and immune response. To test the generality of our results, we assessed adult males of four amphibian species. We found that the body size was larger in urban environment populations in three of four studied species, while the body condition was better in the urban populations of two aquatic newt species. Finally, we found no effect of urbanization on the immune response of individuals of any species. In conclusion, we show that different species of amphibians may be affected differently by anthropogenic habitat alteration depending on their specific ecology. 相似文献