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111.
This article assembles the results of three multicountry surveys on variety performance and adoption patterns to measure the impacts of maize research in West and Central Africa from 1981 to 2005, and uses cost data since 1971 to compute social rates of return on public investments in maize research in the region. Adoption of modern varieties increased from less than 5% of the maize area in the 1970s to about 60% in 2005, yielding an aggregate rate of return on research and development (R&D) investment of 43%. The estimated number of people moved out of poverty through adoption of new maize varieties rose gradually in the 1980s to more than one million people per year since the mid 1990s. Over half of these impacts can be attributed to international maize research at IITA and CIMMYT. The article concludes with a discussion of strategic options to enhance the impacts of maize research in the region.  相似文献   
112.
Patterns in property values provide strong signals about the future and sustainability of land use. This paper analyzes the determinants of land value in an Amazonian frontier settlement. We estimate hedonic price functions to identify factors that affect the value of farm properties in the western Brazilian Amazon. Distance to market explains nearly one-third of the variation in farm value, as predicted by the von Thünen model. After controlling for location relative to the central market and for municipality, we find that investment in the farms (as reflected in the stocking rate of pastures and the establishment of home gardens) has the next largest impact on land value. The value per hectare of land is negatively related to total lot size, suggesting that any economies of scale are outweighed by the cost of accessing remote corners of large properties. We do not find that land values are related to available measures of biophysical factors or to historic or current land use. Our results do not identify any premium for forest cover or for land uses considered to be more sustainable than pasture on the property itself. However, farm values are affected by neighboring land cover, specifically, the extent of barren land. Thus, local knowledge of factors contributing to future productivity, as summarized in land values, confirms that soil exhaustion can lead to a general decline in property values, while investments in a property both as a homestead and as a farm can help sustain frontier settlements.  相似文献   
113.
多伦多大学的OTA:历史及一个核心问题的讨论   总被引:1,自引:0,他引:1  
多伦多大学的OTA(教学促进办公室)成立于2002年1月,其职责是改变多伦多大学传统的科研主宰型文化、帮助教师开发教学技能、并通过科学的晋升和薪酬机制确保科研型大学的教师在教学和科研之间建立有效的平衡。这必然涉及到一个最根本的问题:在高级职称的晋升中,卓越的教学业绩是否能与一流的科研成果相提并论?对这一问题,学生、教师、管理层持有不同的观点,西欧、澳洲、北美地区也有不同的做法。  相似文献   
114.
The stochastic approach to index numbers has been successfully applied to the estimation of inflation, the world interest rate and international competitiveness.?One distinct advantage of this approach is that it provides the whole distribution of the index, not simply one value. In this article, we extend the stochastic approach to the estimation of a stock market index. We demonstrate how this approach can be used to identify ‘redundant stocks’ that do not contribute significantly to the overall index.?For index tracking purposes, these stocks can be safely excluded.  相似文献   
115.
In Sub-Saharan Africa, fish ponds are often an integral part of farming systems but have suffered from a lack of viability and sustainability. The present study aims to understand the strategies used by fish farmers to overcome economic and environmental constraints. In 2008 and 2009, fish farmers were surveyed in Central and Western Cameroon, and the fish production systems were classified by cluster analysis. Four broad types were identified according to the complexity of household operations. The development of extensive systems (large-scale and low-input) in rural areas of central Cameroon is induced mainly by abundant available land. For semi-intensive systems in both regions (small-scale and high-input in the Western Region, large-scale and high-input in peri-urban areas of the Central Region), horizontal integration is not sufficient to make fish production profitable and sustainable. More intensive fish farms tend towards vertical integration, in which farmers establish close links with input suppliers. Main causes of low productivity of semi-intensive systems (1–2?t/ha/yr) are both lack of knowledge of fish farming principles by farmers and lack of technical improvement by extension agents and researchers which need to consider the local complexity of farming systems to develop and intensify fish production. The adaptation of development strategies to socio-economic and environmental contexts is a necessity to hope for an increase in fish pond aquaculture production in Africa.  相似文献   
116.
This article revisits a conventional wisdom that inorganic fertiliser use across sub‐Saharan Africa is too low. This expectation that more farmers should be using inorganic fertiliser, and at higher rates, implies it is profitable to use rates higher than observed if farmers are rational expected profit maximisers. We obtain consistent estimates of the effects of applied nitrogen on rice production. We find the yield response to applied nitrogen to be low in the main rice growing farming system. Farmer behaviour is not inconsistent with expected profitability which is limited by a low yield response to applied fertiliser, high transportation costs, and low selling prices for rice in rural areas. In particular, we do not find any farmers for whom applied nitrogen is profitable that are not using fertiliser in the study sample for each of our survey years (2010 and 2012).  相似文献   
117.
Achieving the Sustainable Development Goals (SDGs) in African agriculture requires a better understanding why high levels of poverty and resource degradation persist in African agriculture despite decades of policy interventions and development projects. In this article, we hypothesize that policies need to account for the key features of the semi‐subsistence crop–livestock systems (CLS) in the region to become effective. The semi‐subsistence CLS are characterized by a high degree of biophysical and economic heterogeneity and a complex, diversified production system involving a combination of subsistence and cash crops with livestock. We investigated the potential for interventions proposed by the Government of Kenya to meet the SDGs by 2030. The analysis uses an integrated modeling approach designed to deal with the key features of these systems. A strategy that stimulates rural development, increases farm size to a sustainable level, and reduces distortions and inefficiencies in input and output markets could lead to a sustainable development pathway and achieve the SDGs for rural households dependent on CLS.  相似文献   
118.
Extreme interannual variability of precipitation within Ethiopia is not uncommon, inducing droughts or floods and often creating serious repercussions on agricultural and nonagricultural commodities. A dynamic climate module is integrated into an economy‐wide model containing a detailed zonal level agricultural structure. This coupled climate‐economic model is used to evaluate the effects of climate variability on prospective irrigation and infrastructure investment strategies, and the ensuing country‐wide economy. The linkages between the dynamic climate module and the economic model are created by the introduction of a climate‐yield factor (CYF), defined at the crop level and varied across Ethiopian zones. Nine sets of variable climate (VC) data are processed by the coupled model, generating stochastic wet and dry shocks, producing an ensemble of potential economic prediction indicators. Analysis of gross domestic product and poverty rate reveal a significant overestimation of the country's future welfare under all investment strategies when climate variability is ignored. The coupled model ensemble is further utilized for risk assessment to guide Ethiopian policy and planning.  相似文献   
119.
120.
This study attempted to gain insights on Brazilian consumers’ subjective knowledge of sodium content in processed and homemade foods and their purchase intent for products with reduced‐sodium content. A questionnaire was distributed to 409 consumers selected by convenience quota sampling. We found that Brazilian consumers were concerned about the amount of salt (sodium chloride) in the products they consumed, regardless of educational levels, income, age, lifestyles, or health conditions. However, they still considered their consumption to be above WHO‐recommended limits and had little subjective knowledge about the term ‘sodium’. While processed products were considered the main contributors of high‐sodium intake, participants were not concerned about addition of salt at the table and salt in homemade food. The majority of respondents rarely read the sodium content on food labels; however, men and older individuals were more likely to read label information on sodium content. Products with reduced sodium were found to have market appeal, which justifies investments in research to develop these products. Therefore, in addition to the efforts to reduce sodium in the processed‐food industry, it is necessary to promote awareness about the importance of food labelling, especially sodium content, and the need to reduce salt in homemade food and additions during meals.  相似文献   
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