排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
Les auteurs s'intéressent aux disparités salariales entre les différents groupes de migrants qualifiés qui travaillent en grand nombre pour le secteur privé dans les États du Conseil de coopération du Golfe. Ils se demandent notamment si la prime salariale des Occidentaux (par rapport aux travailleurs venus d'Asie ou d'autres États arabes) découle d'éventuels a priori des employeurs. L'analyse, qui repose sur des données de 2012–2014 et sur deux méthodes de décomposition classiques, infirme l'hypothèse: les caractéristiques observables relatives à la productivité expliquent entre un tiers et trois quarts des écarts; le coût d'opportunité de la migration, supérieur pour les Occidentaux, explique la portion restante. 相似文献
2.
In an ordinary linear program a single objective vector is constructed and one attempts to choose a decision vector to optimize this objective. Often multiple criteria exist or exact estimates for the components of a single objective vector are not entirely clear. For these cases a conservative decision-maker may want to choose an alternative that maximizes the objective value under the worst foreseeable circumstances. Herein we develop a unified framework for applying the maximin criterion to problems with various degrees of uncertainty attached to the objective vector. Three cases are solved via linear programming: (1) Complete Information, (2) Partial Information, and (3) Total Ignorance. It is shown that the functional value of the maximin solution decreases in a convex manner with increasing uncertainty. In addition certain relationships between maximin and efficient solutions are provided. Finally, an extension to integer constrained decision variables is presented. 相似文献
3.
Fossil fuels are an important source of energy for Ontario Hydro and purchases exceed $100 million per year. This paper describes a computer simulation of the inventory situation over an eight-year period, which is being used to assess the relationship between order flexibility and the target carry-over stocks at the beginning of each shipping season. A simple way of presenting the results for management evaluation is illustrated. Variations of the model are used to assess random influences, such as strikes, and to determine the economic balance between holding costs and stock-outs. 相似文献
4.
5.
6.
7.
Jennifer Willett Alonso Tamayo Jeffrey Kern 《International Journal of Social Welfare》2020,29(4):335-345
As eco‐social work practice and scholarship continues to grow, multiple frameworks are emerging to help guide the work. In this study, we interviewed 59 people affected by environmental injustice. Participants identified components within both environmental injustice and sustainability, as well as gaps that these models individually do not support. Therefore, we suggest that merging environmental justice with sustainability through centering justice (a component within environmental justice), and also finding solutions through technological advances (a component within sustainability), may best support these communities. In addition, the participants discussed the need for support, which social workers can provide. 相似文献
8.
Risk of Illness with Salmonella due to Consumption of Raw Unwashed Vegetables Irrigated with Water from the Bogotá River
下载免费PDF全文
![点击此处可从《Risk analysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Laura X. Henao‐Herreño Ana M. López‐Tamayo Juan P. Ramos‐Bonilla Charles N. Haas Johana Husserl 《Risk analysis》2017,37(4):733-743
The Bogotá River receives untreated wastewater from the city of Bogotá and many other towns. Downstream from Bogotá, water from the river is used for irrigation of crops. Concentrations of indicator organisms in the river are high, which is consistent with fecal contamination. To investigate the probability of illness due to exposure to enteric pathogens from the river, specifically Salmonella, we took water samples from the Bogotá River at six sampling locations in an area where untreated water from the river is used for irrigation of lettuce, broccoli, and cabbage. Salmonella concentrations were quantified by direct isolation and qPCR. Concentrations differed, depending on the quantification technique used, ranging between 107.7 and 109.9 number of copies of gene invA per L and 105.3 and 108.4 CFU/L, for qPCR and direct isolation, respectively. A quantitative microbial risk assessment model that estimates the daily risk of illness with Salmonella resulting from consuming raw unwashed vegetables irrigated with water from the Bogotá River was constructed using the Salmonella concentration data. The daily probability of illness from eating raw unwashed vegetables ranged between 0.62 and 0.85, 0.64 and 0.86, and 0.64 and 0.85 based on concentrations estimated by qPCR (0.47–0.85, 0.47–0.86, and 0.41–0.85 based on concentrations estimated by direct isolation) for lettuce, cabbage, and broccoli, respectively, which are all above the commonly propounded benchmark of 10?4 per year. Results obtained in this study highlight the necessity for appropriate wastewater treatment in the region, and emphasize the importance of postharvest practices, such as washing, disinfecting, and cooking. 相似文献
9.
Many of the contemporary models used to describe the behavior of the mineral industries assume a competitive market i.e. one in which market price is equal to marginal production cost. One such recent model of the worldwide copper industry is the MIDAS-II model developed for the Bureau of Mines [3, 4]. This model is used to project production and prices up through the year 2000. The purpose of this paper is to demonstrate the importance of the assumed market structure in the construction of these forecasts. If the market structure of the US copper industry is assumed to be comprised of a few large firms (an oligopoly), then forecasts based upon exactly the same data base differ significantly from the competitive market assumption. 相似文献
10.
Usamah F. ALFARHAN Samir AL‐BUSAIDI 《International labour review / International Labour Office》2019,158(2):273-295
This article discusses earnings differentials among skilled Western, Arab and Asian migrants, who constitute most of the private sector labour force in Gulf Cooperation Council (GCC) countries, during the period 2012–14. Using two standard decomposition methodologies, it investigates the view that Westerners are paid premium rates due to the unobserved perceptions of private employers. The results indicate that while one‐third to three‐quarters of real hourly earnings differentials are attributable to differing observed levels of productivity‐related characteristics, the remainder are due to the incorporation of higher opportunity costs for Westerners into the bargaining process. The potential effect of unobserved perceptions is found to be irrelevant to observed earnings differentials. 相似文献