985 resultados para AAS


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During the rollout of CGIAR Research Program on Aquatic Agricultural Systems (AAS) in Tonle Sap in 2013, water management was highlighted as one of the key development challenges. With limited capacity to regulate water, the situation oscillates between too much water in the wet season and too little water in the dry season. Access to and availability of water were seen by local communities as major limitations for aquatic and agricultural production, impacting on functions that include the lake fishery, intensive (dry season) rice crops, recession rice, rainfed rice and floating rice by the lakeside. For both fish and rice production, water and water management are determined principally by the natural flooding of the Tonle Sap Lake. This study is based on a community survey on water access, availability and management and was conceived out of the AAS consultation process and was developed to help identify existing practices in water use and management, as well as best practices where lessons can be learned and promising activities scaled out to other communities. The community survey also aims to understand, identify and analyze constraints and opportunities related to water, and includes a gender perspective to better understand the role of women in water management and use.

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The process of rolling out the CGIAR Research Program on Aquatic Agricultural Systems (AAS) in 12 target villages in the Tonle Sap region in Cambodia throughout 2013 involved several important tasks at different stages. This report covers one of those tasks: the Community Life Competence Process (CLCP), commonly referred to by stakeholders as "visioning". It has two main objectives: (1) to document the community visioning process, including the development of a community action plan and NGO work plan to monitor progress; and (2) to document village and network profiles of key community stakeholders at the village level.

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The CGIAR Research Program on Aquatic Agricultural Systems (AAS) seeks to reduce poverty and improve food security for many small-scale fishers and farmers who are dependent on aquatic agriculture systems by partnering with local, national and international partners to achieve large-scale development impact. This study on promising practices in food security and nutrition assistance to vulnerable households in the Tonle Sap region forms part of the preliminary research that informs AAS work in the highly productive Mekong Delta and Tonle Sap Lake floodplain. The study aims to identify and learn from promising practices that have had a positive impact on the food security and nutrition of vulnerable households in the Tonle Sap region.

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The CGIAR Research Program on Aquatic Agricultural Systems (AAS) seeks to reduce poverty and improve food security for the millions of small-scale fishers and farmers who depend on the world’s floodplains, deltas and coasts. AAS combines more conventional approaches for introducing and scaling technical innovations, such as applied research and training, with approaches that foster innovation and promote institutional and policy change. Specifically, AAS utilizes participatory action research with communities to identify technology and policy solutions that best meet community long-term needs. One of the themes identified under AAS is the role of self-help groups in increasing livelihood resilience of agriculture and fisheries communities. As AAS establishes a hub of operations in Cambodia, AAS and Oxfam America are cooperating to investigate the potential of community-based self-help groups as a strategy for AAS implementation. As part of this cooperation, Oxfam America undertook this consultancy to analyze and describe the role, efficiency and effectiveness of the various types of self-help groups in Cambodia. This report gives an overview of this program which aims to conduct a field-based study to identify the types, main characteristics and effectiveness of self-help groups, with a particular focus on livelihood resilience of agriculture and fisheries communities.

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The objective of the current report produced for the CGIAR Research Program on Aquatic Agricultural Systems (AAS) is to provide basic information on key constraints driving poverty and vulnerability in aquatic agricultural systems in the Tonle Sap region in Cambodia. Six objectives and corresponding research themes are included in the program: sustainable increases in productivity; equitable access to markets; resilience and adaptive capacity; empowering policies and institutions; reduced gender disparity; and expanded benefits for the resource-poor. In this report, the authors review the main aquatic agricultural systems (status, specific policies and strategies, interventions, challenges, and options), then review the main drivers of change. This leads to an identification of plans and strategies important to AAS, with a particular focus on perspectives, gaps and opportunities in national policies, community engagement, increased benefits, adaptive capacity, and gender. This review, of potential interest to decision makers and all development partners, leads to conclusions and recommendations aimed at policymakers and institutional as well as private investors in development.

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This paper presents data and findings from focus group discussions in study communities selected by the CGIAR Research Program on Aquatic Agricultural Systems (AAS) in the Western Province of Zambia. The discussions focused on cultivated crops and vegetables collected from open fields and consumed as food. Participatory tools for agricultural biodiversity (agrobiodiversity) assessment were used to capture community perspectives on plant species and varietal diversity; factors influencing the availability and use of plants for food; unique, common and rare crop species cultivated in a community, identified through a four-cell analysis methodology; and core problems, root causes, effects and necessary actions to tackle them, using problem tree or situation analysis methods.

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This working paper aims to synthesize and share learning from the experience of adapting and operationalizing the Research in Development(RinD) approach to agricultural research in the five hubs under the The CGIAR Research Program on Aquatic Agricultural Systems. It seeks to share learning about how the approach is working in context and to explore the outcomes it is achieving through initial implementation over 3 ½ years. This learning can inform continuation of agricultural research in the second phase of the CGIAR research programs and will be useful to others aiming to implement research programs that seek to equitably build capacity to innovate in complex social-ecological systems. Each of the chapters in this working paper have shown that RinD has produced a range of outcomes that were often unexpected and broader in scope than might result from other approaches to agricultural research. RinD also produces innovations, and there is evidence that it builds capacity to innovate.

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There is increasing awareness that integrating gender into development frameworks is critical for effective implementation of development strategies. In working to alleviate rural poverty, the CGIAR Research Program on Aquatic Agricultural Systems (AAS) recognizes that “business as usual” gender integration approaches will not deliver lasting and widespread improvements in agricultural productivity, poverty reduction and food security. In response, AAS operationalized a gender transformative approach. The approach is informed by conceptual frameworks that explicitly recognize the potent influence of social relations on creating and perpetuating gender inequalities. In this way, AAS aims to address the underlying causes of rural poverty and gender inequality in Zambia’s Barotse Floodplain, where people rely extensively on riverine and wetland ecosystems for food and livelihood security. A central question guiding the research program is “How do social norms and gendered power relations influence agricultural development outcomes?” The findings presented in this report provide insights that help answer this question. The report presents a review of literature relevant to livelihoods, ecosystem services, and gender and social relations in Zambia, with a specific focus on Western Province, where AAS is currently implemented. It also presents a synthesis of findings of a social and gender analysis conducted in 2013 in 10 focal communities situated in and around the Barotse Floodplain.

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The CGIAR Research Program on Aquatic Agricultural Systems (AAS) is collaborating with partners to develop and implement a foresight-based engagement with diverse stakeholders linked to aquatic agricultural systems. The program’s aim is to understand the implications of current drivers of change for fish agri-food systems, and consequently food and nutrition security, in Africa, Asia and the Pacific. Partners include the Global Forum on Agricultural Research (GFAR), the Forum for Agricultural Research in Africa (FARA) and the African Union’s New Partnership for Africa’s Development (AU-NEPAD). A key part of the program was a participatory scenario-building workshop held in July 2015 under the theme of "futures of aquatic agricultural systems and implications for fish agri-food systems in southern Africa." The objectives for the workshop were (i) to engage local stakeholders in exploring plausible futures of aquatic agricultural systems, and (ii) to broker and catalyze collaborative plans of action based on the foresight analysis. This report presents technical findings from the workshop. The CGIAR Research Program on Aquatic Agricultural Systems (AAS) is collaborating with partners to develop and implement a foresight-based engagement with diverse stakeholders linked to aquatic agricultural systems. The program’s aim is to understand the implications of current drivers of change for fish agri-food systems, and consequently food and nutrition security, in Africa, Asia and the Pacific. Partners include the Global Forum on Agricultural Research (GFAR), the Forum for Agricultural Research in Africa (FARA) and the African Union’s New Partnership for Africa’s Development (AU-NEPAD). A key part of the program was a participatory scenario-building workshop held in July 2015 under the theme of "futures of aquatic agricultural systems and implications for fish agri-food systems in southern Africa." The objectives for the workshop were (i) to engage local stakeholders in exploring plausible futures of aquatic agricultural systems, and (ii) to broker and catalyze collaborative plans of action based on the foresight analysis. This report presents technical findings from the workshop.

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Conventional alkali-activated slag (AAS) cements suffer from significant drying shrinkage which hinders their widespread application. This paper investigates the potential of using commercial reactive MgO to reduce the drying shrinkage of AAS. Two different reactive MgOs were added at a content of 2.5-7.5 wt% of the slag, which was activated by sodium hydroxide and water-glass. The strength and the drying shrinkage of those reactive MgO modified AAS (MAAS) pastes were measured up to 90 days. It is found that MgO with high reactivity accelerated the early hydration of AAS, while MgO with medium reactivity had little effect. The drying shrinkage was significantly reduced by highly reactive MgO but it also generated severe cracking under the dry condition. On the other hand, medium-reactive MgO only showed observable shrinkage-reducing effect after one month, but the cement soundness was improved. The hydration products, analysed by X-ray diffraction, thermogravimetric analysis and scanning electron microscopy techniques, showed that Mg was mainly incorporated in the hydrotalcite-like phases. It is concluded that the curing conditions and the time of hydrotalcite-like phases formation and their quantity are crucial to the developed strength and shrinkage reduction properties of MAAS, which are highly dependent on the reactivity and content of reactive MgO. Crown Copyright © 2013 Published by Elsevier Ltd. All rights reserved.

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随着基质辅助激光解吸/离(MALDI)和电喷雾电离(ESI)技术的发展,“软电离”质谱在一些新领域正在发挥着越来越大的作用。本论文运用这些新技术对二萜类生物碱、环糊精与氨基酸复合物和环糊精与肽复合物进行了系统地研究。具体研究结果如下:一、附子中二萜类生物碱的质谱研究使用基质辅助激光解吸飞行时间质谱仪(MALDI-TOF/MS)研究了附子提取物中C-19二萜类生物碱。实验结果表明:MALDI适合同时检测粗提物中多种生物碱,并且在分析速度和灵敏度方面明显优于其它方法。在附子甲醇提取物中检测到三类14种已知生物碱(单双酯型生物碱、阿替生型生物碱和脂类生物碱)和三种未知生物碱。同时还进行了生物碱萃取方法优化实验研究,并探讨了复方煎煮过程中成分-成分之间的相互作用。研究发现:生物碱的极性、碱性和毒性与生物碱C-8取代基相关,而且该基团在电离过程中容易形成中性碎片;在煎煮过程中甘草促进附子中剧毒的双酯型生物碱水解为低毒性的单酯型生物碱,从而证实了复方解毒机理。把电喷雾质谱(ESI-MS)和多级串联质谱(MS~n,n = 2-10)结合用以分析附子中脂类生物碱的成分。ESI-MS能够依据分子量的不同实现脂类生物碱的有效分离,并且Ms~n可以提供有关分子结构的信息。这样,就在附子乙醚提取物中确认出了12种已知脂类生物碱,并发现四种新的脂类生物碱。二、环糊精/氨基酸和环糊精/肽两种复合物的气相行为在10mM醋酸铵缓冲的环糊精(CD)/氨基酸(AAs)溶液的ESI-MS谱中,分别观察到α、β-CD与9种氨基酸复合物的正负离子;结合碰撞诱导解离(CID)技术确定了气相复合物的价键性质和结构。溶液中CD和AAs之间的疏才斜目互作用由于ESI过程中溶剂化作用的减弱而减弱,甚至完全消失,而分子之间的静电作用和氢键可能因此被加强。去质子化复合物的CID实验显示:当CD复合物从溶液相转入气相时,分子之间的主要作用力发生变化,静电相互作用成为主要作用力。研究还发现:β-CD/芳香氨基酸复合物的稳定性与氨基酸侧链和cD空腔之间的尺寸适合有关。因为CD/芳香氨基酸复合物与CD/其它氨基酸复合物的解离途径是不同的。由于芳香侧链被包结在CD空腔内,当CD/芳香氨 基酸复合物解离时,CD发生“爆裂”。为了进一步解释气相中CD和氨基酸的复合形式,引入氨基酸侧链极性表面积以评价氨基酸侧链对复合物稳定性的贡献。结果显示:氨基酸侧链羟基对复合物稳定性没有明显影响,这更加证明了在气-液两相中CD/芳香氨基酸复合物的结构是一致的。用ESI-MS和MS~n对α、β-CD与谷胱甘肽(GSH)及其修饰物进行研究,实验结果表明:两种环糊精均能催化GSH氧化反应。1:1和1:2CD/GSH复合物的CID揭示了分子之间具有较强的氢键作用。与GSH二聚体相比,1:2复合物作为催化氧化反应的中间体能够提供双分子GSH氧化反应的空间条件。此外,在1:1CD/GSH复合物的CID谱中观察到了GSH的氧化产物,说明在cID的离子富集和活化过程中会发生复合物离子-复合物离子之间的相互作用。这一结果不仅解释了CD催化反应的机理,同时揭示了气相复合物的化学性质。

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燃料电池以其高效、环境友好的发电方式,被誉为21世纪的能源技术。其中,直接甲醇燃料电池(DMFC)更以燃料甲醇来源丰富,价格低廉,储存、携带方便而成为近年的研究热点。但是,DMFC在其实用化之前还需要解决一些重要问题,其中的关键之一就是高性能的贵金属催化剂的研究。我们知道,甲醇的电化学活性要低于氢气三个数量级;而且甲醇在R表面进行电化学氧化时,其中间解离吸附产物会造成贵金属催化剂中毒,显著降低了催化剂的活性。因此,要使DMFC具有相当高的电流密度和运行稳定性,就需要对贵金属催化剂制备进行不断的研究和改进。在本文的工作中,主要从Pt/C催化剂的制备方法、新型碳纳米管载体、稀土助催化剂等三个方面进行了研究和探索,取得的具体结果如下:1.Pt/C催化剂制备方法的研究与改进(1)在本组已有的研究结果基础上,对预沉积还原法进行了一些改进,采用原子吸收光谱(AAS)进行表征,发现Pt的利用率得到了明显的提高。采用X射线衍射。(RD)、透射电子显微镜(TEM)和BET表征铂的粒径、晶态结构和催化剂特性,分析表明,经过改进的预沉积还原法制备的催化剂仍然具有良好的分散性、较小的粒径、较低的晶态结构和良好的催化剂特性,电化学测试证明其性能要优于同等的E-TEK催化剂。(2)借鉴冶金学中的相关技术,提出了一种新的Pt/C催化剂制备方法一程序升温焙烧法。该方法的具体步骤增强了金属催化剂粒子和碳载体之间的相互作用力,提高了碳载体的导电性,并且形成了部分有利于催化反应进行的活性晶态结构。得到的R/C催化剂获得了近似E-TEK催化剂的催化活性,在具体方法上仍有改进的潜力。采用了同(1)的催化剂表征方法。2.甲醇电化学氧化稀土助催化剂研究在直接甲醇燃料电池Pt/C催化剂的研究过程中,一个重要的方面就是助催化剂的研究,并且已经得到了较好的结果。本工作选用了稀土元素为研究对象,因为稀土元素属于过渡金属,具有丰富的d电子轨道,易于和金属形成强的类化学键的吸附作用,并且能够和有机小分子形成多种配位化合物。经过初步的工作,发现了有些稀土离子如Sm3+能够在Pt表面吸附并且对甲醇电化学氧化具有较稳定的促进作用,采用循环伏安法,计时电流,交流阻抗等电化学方法进行了表征。根据实验结果,对其反应机理进行了初步的探讨。3.碳纳米管(CNTs)作为贵金属催化剂载体的研究碳纳米管(CNTs)由于其结构上的特殊性(径向尺寸为纳米量级,轴向尺寸为微米量级)而表现出典型的一维量子材料,同时具有较高的机械强度和超常的电学性能,能够为化学反应提供纳米级的反应场所,因此受到了化学界包括电化学研究人员的极大关注。已经在作为贵金属催化剂载体方面进行了一些研究,本工作的主要内容就是针对Pt/CNTs催化剂对碳纳米管的要求,对其预处理方法进行了改进,采用了如(1)中的催化剂表征方法和(2)中的相关电化学方法进行测定,发现碳纳米管作为贵金属催化剂载体时,对它的纯化处理方法的不同明显地影响了其载体性质和催化剂的活性。