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Elvis Parraguez-Vergara Beatriz Contreras Neidy Clavijo Vivian Villegas Nelly Paucar Francisco Ther 《国际农业可持续发展杂志》2018,16(4-5):326-341
The current challenge for world agriculture is to provide food for a growing population, within a context of environmental degradation and economic inequality. The challenge is how to produce accessible, healthy, diverse, nutritious, safe and abundant food in a way that is sustainable, allowing farmers to exert food sovereignty while at the same time addressing ecosystem conservation. The aim of this study is to explore the potential contribution of traditional agriculture to food sovereignty and also to understand the challenges that indigenous communities are facing today. Our case studies are from six Latin-American countries: Chile, Peru, Ecuador, Colombia, Guatemala and Mexico, where we carried out semi-structured, guided visits and field observations. Our results shed light on how traditional agricultural knowledge, techniques and practices can contribute to these issues, but also to the need of protecting and recovering the cultural and ecological heritage. There is a need to resolve public management issues, related to development investment, technological packages, cultural loss and gender. If these are not addressed, the potential contribution of ancient agricultural knowledge will fail to contribute to strengthen food sovereignty and maintain the local markets, which are also places for seed exchange, knowledge sharing and social networking. 相似文献
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AbstractIndex funds consist of a subset of stocks, an index tracking portfolio, included in the market index. The index tracking portfolio aims to match the performance of the benchmark index. In this paper, we propose a hybrid model for solving the multiperiod index tracking problem, which includes rebalancing concerns, transaction costs, limits on the number of stocks, and diversification by sector, market capitalization, and stock weight. Our hybrid model combines the genetic algorithm (GA) to select stocks of the index tracking portfolio and mixed-integer nonlinear programming (MINLP) to estimate its weights. Finally, we apply our proposed hybrid model to the S&P500 to find an index tracking portfolio that includes those constraints. The results show that our hybrid model is able to create an index fund whose return rate is similar to the market index with significantly lower risk. 相似文献
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