Until now, the estimation of transient stability transfer limits by means of signal energy analysis has been limited to stable time-domain simulations. The paper adapts this analysis to unstable ...simulations, and extends the method to long-term voltage stability limit estimation as well, thereby proposing a unified approach for both criteria. The method is based on (i) performing transient or long-term time-domain simulations (depending on the type of limit to be found), (ii) extracting the signal energy of the time-varying RMS voltage response at appropriate system buses, and (iii) averaging to obtain a "system" signal energy. In radial power systems, a more localized average is found to provide slightly better limit-estimating performance (i.e. "corridor" signal energy). However, both "system" and "corridor" signal energies are shown to rise asymptotically and predictably to the limit with increasing power for stable cases, and decreasing power for unstable cases. A simple theory explains this behaviour near the limit as being inversely proportional to power transfer, and test cases performed on a validated model of the 1991 Hydro-Quebec system demonstrate the value of the approach.
Etude sur les circuits de commercialisation du lait et des produits laitiers dans les secteurs informael (traditionnel) et formel (paraetatique) de la ville de Bamako au Mali; suivi d' une analyse ...sur l' organisation et les contraintes du circuit de commercialisation des produits laitiers, tout en examinant les perspectives d' amelioration de l' efficacite de ce circuit, et le reseau global de commercialisation du lait et des produits laitiers dans la ville de Bamako.
The Senegalese government is establishing a strategy of multiple use within its coastal protected areas, with community participation in its management. This ongoing study is based on the ...identification and analysis of natural and human effects on Saloum Biosphere Reserve (Senegal), which is also a Ramsar Wetland area. This article points out a few nonrestrictive orientations for integrated management of the protected area and its surroundings. The main objectives of the current management plan are: a permanent monitoring process of the natural resources, training and information about the positive effects of a sustainable conservation strategy, setting up strategies that could improve the living standards of local communities, and promotion of an institutional framework for better management of the biosphere reserve with all actors' participation.
Cancer in Mali, 1987-1988 Bayo, S; Parkin, D M; Koumaré, A K ...
International journal of cancer,
15 April 1990, Letnik:
45, Številka:
4
Journal Article
Recenzirano
Results from the population cancer registry in Bamako, Mali, for the years 1987 and 1988, are presented. The age-standardized incidence for all cancers is high compared with rates reported elsewhere ...in West Africa (119.6 per 10(5) in males and 88.3 per 10(5) in females), but the leading cancers in each sex are the same (liver cancer in males, cervix cancer in females). The incidence of stomach cancer is the highest recorded in Africa, while rates for lung cancer, although low, exceed those in earlier series from registries in the region.
To determine predictive factors of bronchial fistula following pneumonectomy.
In 14 years (1989-2003), we collect 58 cases of bronchial fistula following 725 consecutive pneumonectomy in the service ...of thoracic surgery of the Sainte Marguerite Hospital in Marseilles. There were 53 cases (91.4%) of cancers and 5 cases (8.6%) of various pathology. The average age of the patients was of 61 +/- 10 years (range 24 to 80 years). The sex ratio M/F was 8.7. The software of regression SPSS (version11.5) was used to identify the factors risk of a bronchial fistula after a univariate and multivariate analysis.
The prevalence of the bronchial fistula after a pneumonectomy was 8%.The preoperative factors which increased to a significant degree the incidence of the bronchial dent to the univariate analysis were the chronic smoking (P < 0.001), the existence of COPD (P = 0.001) and of a previous thoracic surgery (P = 0.01). Operational data like a right- side pulmonary resection (P < 0.001), the type of bronchial stup carried out (P = 0.03) as and an extended pneumonectomy to the auricule (P = 0.03) were significant risk factors. With the logistic regression the significant risk factors were the chronic smoking (P = 0.002), the existence of COPD (P = 0.003), a previous pulmonary surgery (P = 0.03) and the right - side of the pneumonectomy (P < 0.001). The indication of the pneumonectomy was retained neither by the univariate analysis, nor by the logistic regression significant risk factors.
The predictive factors of a bronchial fistula after a pneumonectomy are dominated by respiratory co-morbidities. To prevent this complication, we insist on the stop of the tobacco, a better respiratory preparation and the acquisition of a protocol adapted of the bronchial stub after a pneumonectomy particularly on the right side.
Pests and diseases caused by bacteria, nematodes, fungi and viruses cause significant losses to tomato in West Africa. This study, carried-out within the framework of the IPM-CRSP implemented jointly ...by IITA, IER and Virginia Tech. and State University, assesses farmers’ perceptions on tomato pests and analyzes factors affecting pest management decision-making. Surveys were carried out in three tomato production areas where pests and diseases are major agricultural problems encountered by farmers. Data were collected a sample of from 343 farmers through a set of questionnaires on tomato production systems. Farmer’s decision-making in pest management was modeled using an econometrics Logit probability model. Results show that the main disease reported by most farmers is tomato leaf curl viruses transmitted by whitefly (Bemissia tabaci). The spray of chemicals was not effective on whitefly-transmitted viruses, but the observance of host free period could significantly reduce the population of whiteflies. Key factors affecting farmers’ pest management decision-making are gender; share of tomato income from household income and the level of farm income. Men are more involved in tomato production due to access to pesticide and effective demand for pesticides because of incomes (purchasing power). This paper concludes that tomato production can increase significantly if improved varieties tolerant to whitefly viruses are developed and disseminated, and farmers trained on the appropriate use of chemicals using a participatory approach to raise their level of awareness and information on effective pesticide use and pest-management decision-making.
Pests and diseases caused by bacteria, nematodes, fungi and viruses cause significant losses to tomato in West Africa. This study, carried-out within the framework of the IPM-CRSP implemented jointly ...by IITA, IER and Virginia Tech. and State University, assesses farmers’ perceptions on tomato pests and analyzes factors affecting pest management decision-making. Surveys were carried out in three tomato production areas where pests and diseases are major agricultural problems encountered by farmers. Data were collected a sample of from 343 farmers through a set of questionnaires on tomato production systems. Farmer’s decision-making in pest management was modeled using an econometrics Logit probability model. Results show that the main disease reported by most farmers is tomato leaf curl viruses transmitted by whitefly (Bemissia tabaci). The spray of chemicals was not effective on whitefly-transmitted viruses, but the observance of host free period could significantly reduce the population of whiteflies. Key factors affecting farmers’ pest management decision-making are gender; share of tomato income from household income and the level of farm income. Men are more involved in tomato production due to access to pesticide and effective demand for pesticides because of incomes (purchasing power). This paper concludes that tomato production can increase significantly if improved varieties tolerant to whitefly viruses are developed and disseminated, and farmers trained on the appropriate use of chemicals using a participatory approach to raise their level of awareness and information on effective pesticide use and pest-management decision-making.
