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61.
R Ferrero Doria P Guzmán Valls J López Alba M Tomás Ros JL Rico Galiano LO Fontana Compiano 《Canadian Metallurgical Quarterly》1996,20(4):380-383
SETTING: A voluntary community health worker programme, in the Western Cape, South Africa, utilizing volunteers to administer directly observed therapy to tuberculosis (TB) patients. OBJECTIVE: This study describes the perceptions of health team members regarding the voluntary community health worker project. DESIGN: A qualitative, participatory research study utilizing focus groups. RESULTS: TB was perceived by the health team to be a stigmatized disease causing some patients to be reluctant to be associated with the TB control programme. Despite the project's dedicated approach to case-holding, volunteers expressed the need to develop skills in providing more comprehensive care. The volunteers appear to administer a more personalized service to TB patients and can bridge the gap between TB patients and the health agency. CONCLUSION: Sustained evaluation and support seem to be a vital tool in integrating a volunteer project into a health team approach. Its effectiveness appears to depend to a large degree on the people involved. 相似文献
62.
Coordination between medium-term generation planning and short-term operation in electricity markets
This paper analyzes the coordination between medium-term generation planning and short-term operation in electricity markets. This coordination is particularly important from a practical point of view in order to guarantee that certain aspects of the operation that arise in the medium-term level are explicitly taken into account: limited-energy resources and obligatory-use resources. Three different approaches are proposed in order to guarantee that short-term decisions made by a generation company are consistent with its operation objectives formulated from a medium-term perspective. These approaches make use of technical and economic signals to coordinate both time scopes: primal information, dual information, and resource-valuation functions. This paper presents the main advantages and drawbacks of the three approaches and applies them to a case study that uses a conjectural-variation-based representation of the market. 相似文献
63.
Antonio J. Nebro Enrique Alba Francisco Luna 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2007,11(6):531-540
This paper analyzes some technical and practical issues concerning the use of parallel systems to solve multi-objective optimization
problems using enumerative search. This technique constitutes a conceptually simple search strategy, and it is based on evaluating
each possible solution from a given finite search space. The results obtained by enumeration are impractical for most computer
platforms and researchers, but they exhibit a great interest because they can be used to be compared against the values obtained
by stochastic techniques. We analyze here the use of a grid computing system to cope with the limits of enumerative search.
After evaluating the performance of the sequential algorithm, we present, first, a parallel algorithm targeted to multiprocessor
systems. Then, we design a distributed version prepared to be executed on a federation of geographically distributed computers
known as a computational grid. Our conclusion is that this kind of systems can provide to the community with a large and precise set of Pareto fronts that
would be otherwise unknown. 相似文献
64.
Giacobini M. Tomassini M. Tettamanzi A.G.B. Alba E. 《Evolutionary Computation, IEEE Transactions on》2005,9(5):489-505
In this paper, we present quantitative models for the selection pressure of cellular evolutionary algorithms on regular one- and two-dimensional (2-D) lattices. We derive models based on probabilistic difference equations for synchronous and several asynchronous cell update policies. The models are validated using two customary selection methods: binary tournament and linear ranking. Theoretical results are in agreement with experimental values, showing that the selection intensity can be controlled by using different update methods. It is also seen that the usual logistic approximation breaks down for low-dimensional lattices and should be replaced by a polynomial approximation. The dependence of the models on the neighborhood radius is studied for both topologies. We also derive results for 2-D lattices with variable grid axes ratio. 相似文献
65.
For a wide variety of real-world decisions, people must examine numerical tables and intuitively assess the correlations that exist among meaningful variables. The normative properties of correlation coefficients suggest that such decisions should be unaffected by perceptual factors (e.g., changes in row and column locations), semantic factors (e.g., the referents of the numbers), or certain transformations of the variables (e.g., adding a constant or multiplying by a constant). Four experiments demonstrated that judgments based on perceived correlations violate these normative properties. A general model of intuitive covariation assessment was proposed to explain the observed biases. Estimation of this model at the aggregate and individual levels suggested that no single heuristic is consistent with all of the results. Instead, the existence of several qualitatively different types of heuristics was supported. The distribution of individual-level decision rules across types of heuristics was systematically related to contextual factors. 相似文献
66.
Izaskun Barrio Iñigo Legórburu Mario Montes María Isabel Domínguez Miguel A’ngel Centeno José Antonio Odriozola 《Catalysis Letters》2005,101(3-4):151-157
A new preparation method has been developed to produce homogeneous coatings of manganese compounds on alumina-coated monoliths by redox deposition-precipitation using acetone as solvent. The deposition is produced by reduction of manganese permanganate with ethanol. The Lewis acid sites on the alumina catalyze this reaction. Thus, the precipitation is produced preferentially on the surface of the monolith and not in the bulk of the solution. Monoliths prepared by this method are very active for the complete oxidation of oxygenated volatile organic compounds (VOCs). These monoliths consist of a mixture of complex phases including aluminum, sulfated alumina, potassium sulfate and manganese oxide. 相似文献
67.
152 enterococcal isolates and 88 micrococcal isolates obtained from secondary microflora of Arzúa raw cows'-milk cheese at various stages of ripening were characterized. The most frequent Enterococcus specie was E. faecalis. The most frequent Micrococcus specie was M. varians, followed by M. luteus and M. lylae; 27 micrococcal isolates could not be assigned to species. Although most strains of micrococci did not cause appreciable acidification of milk, the proportions of micrococcal isolates displaying proteolytic and lipolytic activities were higher than those for enterococcal isolates. The biochemical and enzymatic characteristics of isolates from both groups displayed considerable variability, even within the same species. In screening microorganisms of this type for suitability as components of cheese starter cultures, it is therefore necessary, as has been pointed out by previous authors, to work with single strains. 相似文献
68.
A 40-yr-old man with a completely transected spinal cord and a spastic neurogenic bladder was conditioned to void upon the presentation of an external stimulus. A classical conditioning paradigm was employed in which strong abdominal shock (UCS) was paired with an initially neutral mild electrical stimulation of the thigh (CS). After the pairing trials, a reliable conditioned response of urination was elicited by the CS alone. The conditioned response did not extinguish over time, and the procedure left the bladder with clinically safe residual amounts of urine. Practical implications of the conditioning technique for the treatment of spastic neurogenic bladder conditions in spinally injured patients are discussed, as is the theoretical significance of conditioning at the reflex level in the absence of cortical involvement. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
69.
70.
The fluorogenic dye 2-methoxy-2,4-diphenyl-3(2H)-furanone (MDPF) has been used for the detection of total protein patterns on polyvinylidene difluoride (PVDF) membranes. Fluorescent staining of protein bands on membranes with this covalent dye is completed in 20 min. Wet membranes are translucent, allowing protein visualization by transillumination with ultraviolet light. The resulting images can be recorded using Polaroid film or a charge-coupled device camera. Electrophoretic bands containing 5-10 ng of protein can be detected on the MDPF-stained Western blot. When proteins are directly transferred to the membrane using a slot blotting device, as little as 0.5 ng of protein can be detected. Previous visualization of protein bands on sodium dodecyl sulfate-polyacrylamide gels with the noncovalent fluorescent dye Nile red (Alba et al., BioTechniques, 1996, 21, 625-626) does not interfere with further MDPF staining and fluorescent detection of these bands transferred to PVDF membranes. Thus, Nile red and MDPF staining can be performed sequentially, allowing the rapid monitoring of total protein patterns on both the electrophoretic gel and Western blot. Using the conditions described in this study, MDPF staining does not preclude further N-terminal microsequencing and immunodetection of specific bands with polyclonal antibodies. 相似文献