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1.
Sustaining and increasing crop production and productivity has to be a major policy thrust for developing countries. Using a simulation approach different production strategies were evaluated conditioned on climate information to derive optimal strategies to help farmers reduce risk and increase productivity. By examining the existence of options in this case planting dates the study provides an analyses of the expected value and risks associated with changing decisions based on the availability of climate forecasts. The 15-March planting date produced the highest mean yield for the two cultivars examined although 1-April, 15-April and 1-May plantings had one to zero probability of crop failures compared to 15-March with crop failures in 4 out of 20 years. Results indicate losses of between 25 and 35 kg/day due to delays in planting from 15-March planting to 1-June planting for the 120- and 150-day cultivar. El niño years were associated with positive yield deviations for both cultivars and most planting dates. Farmers are known to make tactical adjustments to their management in light of information perceived relevant to the prospects of forthcoming crop. Although in its present form most current forecast products do not provide information on onset of the rainfall, however the information they do provide could play a crucial role in helping farmers reduce the risks posed by climatic variability.  相似文献   

2.
Water control is an essential requirement if food and energy crises in Africa are to be resolved on a sustainable basis. The paper reviews the problems and prospects associated with the expansion of irrigation in Africa, where experiences with large and medium scale water management have been of comparatively recent origin. The present status of water development and management issues are approached carefully and cautiously, they can make an important and lasting contribution to the resolution of Africa's food crisis.  相似文献   

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Reports

MEDACTA '93 Modern Educational Technologies  相似文献   

5.
《Geoforum》1988,19(4):433-445
Since a central concern of the geography of international migration is to consider how and why stocks and flows of migrants are variable from country to country, the study of skilled international migration must address policies of individual governments towards local and foreign skilled workers. These policies are most evident in immigration and emigration legislation, regulations and practice, but also, less directly but often of more fundamental significance, in policies in education, manpower planning and towards wages and salaries. In Sub-Saharan Africa there is a wide range of experience of recent skilled international migration, driven by direct and indirect policies pursued by individual governments since independence. At an intercontinental scale the deleterious effects of the global division of labour have not merely been passively accepted; within the continent new patterns of skilled-labour migration have been created by increasingly differentiated economic performance and political relationships. A case study of Kenya, a country of small current net immigration of skilled workers, is used to specify some of the processes that establish the relationships between immigration and emigration policies, and how these have been mediated by conditions for skilled workers. The concluding section of this paper sets the general experience and that of the Kenyan case study in the wider context of the role of the state as a factor in the geography of skilled international migration in the Third World.  相似文献   

6.
Short-term changes in the general circulation of the atmosphere, which may lead to prolonged periods of drought, are catalysts for producing accelerated desertification. In southern Africa the northeastward thrust of desertification from the western and central arid and semi-arid areas (the Karoo) has long been recognised, but up til 1970 research failed to demonstrate a clear-cut relationship between the process of desertification and long term rainfall data. The application of sophisticated analytical techniques to regional rainfall data showed, however, that spatial and temporal variations in the Southern African rainfall pattern have a striking degree of organization. The summer rainfall region of the northeastern part of the subcontinent experiences 16–20 year fluctuations, in contrast with 10–12 year fluctuations in the all-season rainfall region along the southern Cape coast. Concentrating on regionally averaged data for the summer rainfall region, the author used Fourier analysis to confirm the persistence of the quasi 20-year fluctuations since 1840. The wet spell of the late 1970s is expected to die out by 1982 and may be followed by a dry spell running from 1983 to 1992. Policy and management practices should be geared to prevent further desertification during this period.  相似文献   

7.
In this paper, we develop and apply a multi-dimensional vulnerability assessment framework for understanding the impacts of climate change-induced hazards in Sub-Saharan African cities. The research was carried out within the European/African FP7 project CLimate change and Urban Vulnerability in Africa, which investigated climate change-induced risks, assessed vulnerability and proposed policy initiatives in five African cities. Dar es Salaam (Tanzania) was used as a main case with a particular focus on urban flooding. The multi-dimensional assessment covered the physical, institutional, attitudinal and asset factors influencing urban vulnerability. Multiple methods were applied to cover the full range of vulnerabilities and to identify potential response strategies, including: model-based forecasts, spatial analyses, document studies, interviews and stakeholder workshops. We demonstrate the potential of the approach to assessing several dimensions of vulnerability and illustrate the complexity of urban vulnerability at different scales: households (e.g., lacking assets); communities (e.g., situated in low-lying areas, lacking urban services and green areas); and entire cities (e.g., facing encroachment on green and flood-prone land). Scenario modeling suggests that vulnerability will continue to increase strongly due to the expected loss of agricultural land at the urban fringes and loss of green space within the city. However, weak institutional commitment and capacity limit the potential for strategic coordination and action. To better adapt to urban flooding and thereby reduce vulnerability and build resilience, we suggest working across dimensions and scales, integrating climate change issues in city-level plans and strategies and enabling local actions to initiate a ‘learning-by-doing’ process of adaptation.  相似文献   

8.

In this paper, we develop and apply a multi-dimensional vulnerability assessment framework for understanding the impacts of climate change-induced hazards in Sub-Saharan African cities. The research was carried out within the European/African FP7 project CLimate change and Urban Vulnerability in Africa, which investigated climate change-induced risks, assessed vulnerability and proposed policy initiatives in five African cities. Dar es Salaam (Tanzania) was used as a main case with a particular focus on urban flooding. The multi-dimensional assessment covered the physical, institutional, attitudinal and asset factors influencing urban vulnerability. Multiple methods were applied to cover the full range of vulnerabilities and to identify potential response strategies, including: model-based forecasts, spatial analyses, document studies, interviews and stakeholder workshops. We demonstrate the potential of the approach to assessing several dimensions of vulnerability and illustrate the complexity of urban vulnerability at different scales: households (e.g., lacking assets); communities (e.g., situated in low-lying areas, lacking urban services and green areas); and entire cities (e.g., facing encroachment on green and flood-prone land). Scenario modeling suggests that vulnerability will continue to increase strongly due to the expected loss of agricultural land at the urban fringes and loss of green space within the city. However, weak institutional commitment and capacity limit the potential for strategic coordination and action. To better adapt to urban flooding and thereby reduce vulnerability and build resilience, we suggest working across dimensions and scales, integrating climate change issues in city-level plans and strategies and enabling local actions to initiate a ‘learning-by-doing’ process of adaptation.

  相似文献   

9.
The importance of the water balance in determining cropping patterns in West Africa is examined. Crops in each country were ranked in order of area occupied. Crop diversity is reduced when the period of water surplus is very short or very long. The fraction of the cropped area occupied by a particular crop is related to the length of the period of water surplus. Four basic cropping patterns are identified.  相似文献   

10.
This paper is concerned with the relationship between safety and mobile phones with particular reference to Sub-Saharan Africa; and looks at a range of geographical contexts: non-violent, conflict and post-conflict situations. The main part of the paper reports on recent findings of extensive field-work into the use of mobile phones in 11 countries in Sub-Saharan Africa. The findings are important partly because from a welfare view, it is use rather than mere adoption that generates actual benefits to consumers. What the survey finds is that use of the mobile phone is mainly for safety-related purposes and that the countries that fare highest in terms of usage are drawn from the richest and poorest members of the sample. In explaining these results I draw heavily on the relationships and interactions between poverty, inequality and crime. For example, the dominance of Southern African countries is ascribed to their exceptionally high levels of inequality, which, in turn, are due partly to the unequal effects of resource abundance.  相似文献   

11.
Natural Hazards - Despite measures to mitigate drought, study on the extent of agricultural and hydrological drought vulnerability is still neglected in the savanna ecological zone of Nigeria. This...  相似文献   

12.
The debate on housing the urban poor has become more sophisticated since Turner’s original ideas of self-help and self-building by the poor were introduced in the 1970s. Today, the emphasis in housing the poor is on a pluralistic approach that stresses enabling housing provision for the poor by expanding the range of providers to include government, the private sector, the poor themselves, non-governmental agencies, and cooperatives. Official housing policy in Ghana does not reflect the pluralistic approach that prevails in practitioner and academic circles. Using ethnography, this paper presents the housing experience of a typical poor family in Ghana to determine what the poor build. It highlights the obstacles the poor have to overcome to acquire the housing they want. The ethnography provides a basis upon which the mismatch between the pluralistic approach and Ghana’s housing policy can be bridged thus providing a way forward. The paper concludes by emphasizing the importance of the housing industry in poverty alleviation in Ghana.  相似文献   

13.
The debate on housing the urban poor has become more sophisticated since Turner’s original ideas of self-help and self-building by the poor were introduced in the 1970s. Today, the emphasis in housing the poor is on a pluralistic approach that stresses enabling housing provision for the poor by expanding the range of providers to include government, the private sector, the poor themselves, non-governmental agencies, and cooperatives. Official housing policy in Ghana does not reflect the pluralistic approach that prevails in practitioner and academic circles. Using ethnography, this paper presents the housing experience of a typical poor family in Ghana to determine what the poor build. It highlights the obstacles the poor have to overcome to acquire the housing they want. The ethnography provides a basis upon which the mismatch between the pluralistic approach and Ghana’s housing policy can be bridged thus providing a way forward. The paper concludes by emphasizing the importance of the housing industry in poverty alleviation in Ghana.  相似文献   

14.
The present article examines the dynamic linkages between biomass energy consumption, capital stock, human capital and economic growth across selected Sub-Saharan African countries based on dynamic heterogeneous panels of a mean group (MG) and pooled mean group (PMG) techniques. The finding based on PMG as the preferred method reveals that biomass energy consumption, capital stock and human capital are statistically significant, which means aforementioned variables have positive significant impact on economic growth in the countries studied. When an alternative panel estimation techniques of panel cointegration, dynamic OLS (DOLS) and fully modified OLS (FMOLS) are applied, the result based on panel cointegration technique reveals that biomass energy consumption, capital stock, human capital and economic growth are cointegrated as null hypothesis of most statistics are rejected at 1 % level of significance. The finding based on FMOLS shows that biomass energy consumption, capital stock and human capital positively influences economic growth at 1 % level and same result is obtained from panel OLS. The result based on DOLS however reveals that biomass energy consumption and capital stock are significant at 1 % on economic growth while human capital is insignificant. Considering its positive effect on economic growth with little or no environmental degradation when compared with fossil fuel uses, consumption of biomass energy is more preferable in these countries therefore is the best option to adopt by the policy makers of Sub-Saharan African countries.  相似文献   

15.
D. Anhuf 《GeoJournal》1990,20(3):221-230
The study attempts to relate crop yields to climatic events in the Sahelian Zone of Africa. The examples are taken from Senegal, Sudan and Tunisia. Theinvestigation was centered to examine closely the relations between weather and crop yields, that means first of all to analyze the influence of the inter-annual variations of the weather on the yields. The aim was to reveal the dependency of the temporal variability of the yields (1960–1980) on the climatic parameters during the different phenological stages of the plants. This analysis made it possible to develop models of prognosis for different cultivated plants (food crops basically). In general suitable models of forecasts could be established for all food crops. An early and exact prediction of harvest losses or surpluses could reduce negative effects for the respective population in unfavourable, and induce food storage in favourable years.  相似文献   

16.
Semi-arid and dry sub-humid areas (especially in the tropics) are characterized by high inter-annual and intra-seasonal rainfall variability. Agriculture, which employs the bulk of the rapidly increasing populations, is largely rain-fed, low-input based and highly resource dependent. Recent spates of drought have, therefore, exacerbated the now-too-familiar specter of famine and starvation in these areas with glaring examples being the recurring episodes in sub-Saharan Africa since the great Sahel drought of 1969–1973. A great need for accurate and timely hazard forecast products in aid of agriculture thus exists.Several schemes are currently employed by various agencies around the globe in this direction. There does remain, however, a gap between product provision and user expectations. This paper examines this gap suggesting a five-point framework within which it can be addressed as an action agenda for the climate science community. The paper posits that changes are possible to existing methodologies (related to three of these points), which, within the context of current science, can greatly enhance the utility of forecast products for agriculture in marginal areas. The remaining two points have, however, been identified as requiring additional applied research and necessary pointers for addressing these issues are provided. First is the need for appropriate impact-related indicators for intra-seasonal and interannual rainfall variability that are easy to compute, amenable to forecasting and follow closely the experiences of farmers in marginal areas. The second is a consideration of appropriate forecast information formatting and communication medium that guarantee effective feedback between forecast producers and users. Specific examples of the status quo and of work currently underway are cited from southern Africa – a region currently attracting international attention as a result of recent droughts and the threat of famine.  相似文献   

17.
In tunnelling, a reliable geological model often allows providing an effective design and facing the construction phase without unpleasant surprises. A geological model can be considered reliable when it is a valid support to correctly foresee the rock mass behaviour, therefore preventing unexpected events during the excavation. The higher the model reliability, the lower the probability of unforeseen rock mass behaviour. Unfortunately, owing to different reasons, geological models are affected by uncertainties and a fully reliable knowledge of the rock mass is, in most cases, impossible. Therefore, estimating to which degree a geological model is reliable, becomes a primary requirement in order to save time and money and to adopt the appropriate construction strategy. The definition of the geological model reliability is often achieved by engineering geologists through an unstructured analytical process and variable criteria. This paper focusses on geological models for projects of linear underground structures and represents an effort to analyse and include in a conceptual framework the factors influencing such models. An empirical parametric procedure is then developed with the aim of obtaining an index called “geological model rating (GMR)”, which can be used to provide a more standardised definition of a geological model reliability.  相似文献   

18.
The current paper examines the relationship between health financing (public and out-of-pocket health financing), CO2 emission and health outcomes in 35 Sub-Saharan African countries for the period of 1995–2012. The panel unit root and cointegration tests are conducted as pre-tests, followed by the estimation of the parameters using the FM-OLS and DOLS techniques. The findings of the study show the importance of public health financing as one of the major factors that lead to better health outcomes, whereas the out-of-pocket expenditure is found to be harmful to population health since it leads to increase under-5 mortality rate. Although the results show a negative relationship between CO2 and health outcomes, still these results remain inclusive. In addition, the findings reveal the importance of socioeconomic factors such as income and education as key determinants of health outcomes.  相似文献   

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20.
房建宏 《冰川冻土》2012,34(2):455-459
利用1971-2002年青海公路沿线44个气象台站的降水、气温、水汽压、相对湿度、风速、日照百分率等地面气象资料,采用Penman公式计算了蒸发力ET,应用气候诊断方法分析了潮湿系数的变化特征.结果表明:按潮湿系数,干季青海省公路沿线全部为过干区,其他季节可分为过干区、中干区和润干区.近30a以来,干季公路沿线的潮湿系数K值呈减小趋势,而过渡季节、雨季和年度潮湿系数K值均呈增大趋势.而这种变化,主要是由气候的年代际波动造成的.  相似文献   

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