High resolution characterisation of microstructural evolution in Rbx_{x}Fe2−y_{2-y}Se2_{2} crystals on annealing

The superconducting and magnetic properties of phase-separated A$_x$Fe$_{2-y}$Se$_2$ compounds are known to depend on post-growth heat treatments and cooling profiles. This paper focusses on the evolution of microstructure on annealing, and how this influences the superconducting properties of Rb$_x$Fe$_2-y$Se$_2$ crystals. We find that the minority phase in the as-grown crystal has increased unit cell anisotropy (c/a ratio), reduced Rb content and increased Fe content compared to the matrix. The microstructure is rather complex, with two-phase mesoscopic plate-shaped features aligned along {113} habit planes. The minority phase are strongly facetted on the {113} planes, which we have shown to be driven by minimising the volume strain energy introduced as a result of the phase transformation. Annealing at 488K results in coarsening of the mesoscopic plate-shaped features and the formation of a third distinct phase. The subtle differences in structure and chemistry of the minority phase(s) in the crystals are thought to be responsible for changes in the superconducting transition temperature. In addition, scanning photoemission microscopy has clearly shown that the electronic structure of the minority phase has a higher occupied density of states of the low binding energy Fe3d orbitals, characteristic of crystals that exhibit superconductivity. This demonstrates a clear correlation between the Fe-vacancy-free phase with high c/a ratio and the electronic structure characteristics of the superconducting phase.Comment: 6 figures v2 is exactly the same as v1. The typesetting errors in the abstract have been correcte

Locating poor livestock keepers at the global level for research and development targeting

P.K. Thornton, R.L. Kruska, P.M. Kristjanson, R.S. Reid and T.P. Robinson are ILRI authorsMany research and development agencies are committed to halving the number of people living in extreme poverty by 2015. Knowledge of where the poor are, and what characterises them, is patchy at best. Here we describe a global livestock and poverty mapping study designed to assist in targeting research and development activities concerning livestock. Estimates of the numbers of poor livestock keepers by production system and region are presented. While these estimates suffer from various problems, improvements in global databases are critical to improve the targeting of interventions that can meet the challenges posed by poverty and to chart progress against international development indicators

Cattle trypanosomiasis in Africa to 2030

Trypanosomiasis diseases are caused by single-cell organisms and affect both humans and cattle. This indicative study modelled the effect of climate change and population growth on the future range of tsetse flies, their main vector, in sub- Saharan Africa. Projected climate change to 2030 has a limited effect on their distribution. Population growth has more significant consequences, mainly caused by the land-use change that accompanies it. It could reduce the area in which tsetse flies are found by 15% by 2030. The main effect would be in drier areas of western, eastern and southern Africa, and in Ethiopia. Humid areas would be less altered. The authors say that other factors such as disease control efforts and changing agricultural practices may also affect the future range of the flies and of the diseases with which they are associated

Classifying livestock production systems for targeting agricultural research and development in a rapidly changing world

A myriad of agricultural and livestock production systems co-exist in the developing countries. Agricultural research for development should therefore aim at delivering strategies that are well targeted to the heterogeneous landscapes and diverse biophysical and socioeconomic contexts the agricultural production system is operating in. To that end, in the recent past several approaches to spatially delineate landscapes with broadly similar production strategies, constraints and investment opportunities, have been applied. The mapped Seré and Steinfeld livestock production classification, for example, has been widely used for the targeting of pro-poor livestock intervention within ILRI. In this paper we describe potential methodologies for the inclusion of crop-specificity and intensification in the existing Seré and Steinfeld livestock systems classification. We also present some first broad-brush future projections of these detailed crop-livestock production systems. A number of example applications are discussed and recommendations for future improvement and use are made. While the production system classifications are especially useful for bio-physical applications such as livestock-environment interactions and feed assessments, the links with socioeconomic factors still need to be explored further. Also, it is only one of the necessary building blocks for better targeting of research and development efforts. We, however,believe that the proposed system classifications will be of use to a variety of agricultural and livestock scientists and development agents alike. In addition, they serve as practical examples making the case for the use of spatial stratification when targeting agricultural research and development

Genetically improved dual-purpose cowpea. Assessment of adoption and impact in the dry savannah of West Africa

The research reported here has the potential for contributing to a real improvement in the livelihoods of mixed crop-livestock farming households in the dry savannah zone of West Africa through widespread uptake of improved dual-purpose cowpea (IDPC). This technology offers opportunities for the production of more, higher-quality food for poor people and fodder for animals, along with soil-fertility improvement and other social benefits. The study examines issues surrounding the adoption and impact of the new varieties and associated management strategies. A novel approach was taken, combining GIS, a crop model, and household, community and participatory research approaches in northern Nigeria in order to address the following questions: `What types of impact are expected and their magnitude, where is the impact most likely to be felt, and by whom?'. The results suggest that the research investment has been beneficial, and the expected returns are high. Furthermore, the steps taken in order to quantify the benefits versus the costs of this research have identified for researchers, policy makers and development practitioners important considerations and possibilities for speeding up and widening the impact of this technology. First, it is a flexible technology that is appreciated by, and will have the greatest impact on, farming households that are usually poor and living in remoter areas where improved crop and livestock production are especially critical to livelihood strategies. Although the wealthiest households are more likely to be adopters, poorer households have also taken up IDPC. As it is the poorer households that cultivate 75% of the arable land, the potential impact of extending the technology to these more rural, less market-oriented households is huge. Uptake to date has been more likely to occur near wholesale markets in the most densely populated areas. Thus, finding innovative ways to increase access to markets and provide improved seeds and information for farmers in low-population density areas may have potentially large payoffs. The benefit from investment in rural market infrastructure and roads will be reflected in increased uptake of natural-resource-enhancing technologies such as IDPC. Farmer-impact workshops were held and the results pointed towards environmental- and poverty-impact indicators that can be monitored as people experiment with, and adapt, the new varieties and associated management techniques. The study has highlighted opportunities relating to the identification of the benefits of IDPC for livestock which are likely to emerge when data from several years of ongoing integrated crop-livestock trials become available. Given the population, climatic and land-use changes that are likely to occur in West Africa in the coming decades, there is an onus on researchers to streamline the effectiveness of R&D activities so that they benefit the rapidly increasing numbers of poor people in the region. The lessons learnt from the impact assessment study reported here will have much broader applicability in the future than to cowpea research alone. It is hoped that this analysis provides a research and impact-assessment strategy that will be useful for other crops and technologies, and in particular that it provides guidelines for assessments of more integrated natural resource management strategies (including livestock) and technologies. Most importantly, the novel multidisciplinary, multicentre and participatory approaches taken by the cowpea research team are helping to close the researcher-farmer feedback loop. Ultimately this is what will lead to faster and more widespread adoption and impact of new technologies

Mapping climate vulnerability and poverty in Africa

The world’s climate is continuing to change at rates that are projected to be unprecedented in recent human history. Some models are now indicating that the temperature increases to 2100 may be larger than previously estimated in 2001. The impacts of climate change are likely to be considerable in tropical regions. Developing countries are generally considered more vulnerable to the effects of climate change than more developed countries, largely attributed to a low capacity to adapt in the developing world. Of the developing countries, many in Africa are seen as being the most vulnerable to climate variability and change. High levels of vulnerability and low adaptive capacity in the developing world have been linked to factors such as a high reliance on natural resources, limited ability to adapt financially and institutionally, low per capita GDP and high poverty, and a lack of safety nets. The challenges for development are considerable, not least because the impacts are complex and highly uncertain. The overall aims of DFID’s new research programme on climate change and development in sub-Saharan Africa are to improve the ability of poor people to be more resilient to current climate variability as well as to the risks associated with longer-term climate change. The programme is designed to address the knowledge implications of interacting and multiple stresses, such as HIV/AIDS and climate change, on the vulnerability of the poor, and it will concentrate on approaches that work where government structures are weak. To help identify where to locate specific research activities and where to put in place uptake pathways for research outputs, information is required that relates projected climate change with vulnerability data. ILRI undertook some exploratory vulnerability mapping for the continent in late 2005 and early 2006, building on some livestock poverty mapping work carried out in 2002. The work described here is a small piece of a larger activity that involved the commissioning of several studies on climate change and the identification of the critical researchable issues related to development. A project inception meeting was held with research collaborators, to discuss analytical approaches and assess data availability. Over the succeeding few months, data were assembled and analysis undertaken. This involved the downscaling of outputs from several coupled Atmosphere-Ocean General Circulation Models (GCMs) for four different scenarios of the future, and possible changes in lengths of the growing period were estimated for Africa to 2050 for several different combinations of GCM and scenario (we used the SRES scenarios of the IPCC). Results are presented on the basis of agricultural system types by country, using a systems classification as a proxy for the livelihood options available to natural resource users. From this, we identified areas that appear to be particularly prone to climate change impacts. These include arid-semiarid rangeland and the drier mixed systems across broad swathes of the continent, particularly in southern Africa and the Sahel, and coastal systems in eastern Africa. The next stage was to consider the biophysical and social vulnerability of these and other areas. To characterise sub-Saharan Africa in terms of vulnerability, on the same country-by-system basis as was done for the climate change impacts, a set of proxy indicators developed at the workshop was pragmatically assessed in relation to data sources, while being guided by the experiences of others in the area. A final set of fourteen indicators was used; three are associated with natural capital, one with physical capital, two with social capital, six with human capital, and two with financial capital. We carried out statistical analysis and reduced this set of fourteen proxy indicators to four components, which were then used to construct an “overall” indicator of vulnerability, and systemsby- countries were then classified in quartiles. These results were then qualitatively combined with the climate change hotspot analysis. The results should be treated as indicative only, and we would caution strongly against their over-interpretation, particularly because the uncertainty associated with them is not yet known. Results do indicate, however, that many vulnerable regions are likely to be adversely affected in sub-Saharan Africa. These include the mixed arid-semiarid systems in the Sahel, arid-semiarid rangeland systems in parts of eastern Africa, the systems in the Great Lakes 4 region of eastern Africa, the coastal regions of eastern Africa, and many of the drier zones of southern Africa. There are several limitations to the analysis and to the availability of data for such work. For the future, considerable emphasis needs to be placed on collaborative efforts to collect and greatly improve the store of baseline information, on understanding very well the needs of potential users, on developing more flexible and generic frameworks for assessing vulnerability, taking advantage of the experiences of others in vulnerability assessment work in developing-country contexts through southsouth collaboration, and on incorporating scenario analysis into the impact assessment framework. The project also involved a study of the potential uses of information concerning climate variability and climate change for effective decision-making. A small survey of potential users was carried out. Findings of the survey confirm the results of other scoping studies: there are broad needs across many different sectors in terms of capacity building and opportunities for research in the future, including vulnerability mapping at different levels. The report concludes with a discussion of the feasibility of expanding the methods and tools used here to develop a tool box that could be used for cross-sectoral ex-ante assessment of interventions related to climate change and coping mechanisms. There are several challenges that have to be addressed, but there are good prospects for developing a useful framework. The work has highlighted two other key points. First, even allowing for the technical problems and uncertainties associated with the analysis, it is clear that macro-level analyses, while useful, can hide enormous variability concerning what may be complex responses to climate change. There is considerable heterogeneity in households’ access to resources, poverty levels, and ability to cope. Vulnerability and impact assessment work can certainly be usefully guided by macro-level analyses, but ultimately this work has to be done at regional and national levels. Second, these results have underlined that local responses to climate change through time are not necessarily linear. In terms of adaptation strategies, far more work is needed on the dynamics of change through time and on the dynamics of household responses. If adaptation itself has to be seen as an essentially dynamic, continuous and non-linear process, this has considerable implications for the tools and methods needed to guide it, and for the indicators and threshold analyses that will be needed. The sciences of climate modelling and vulnerability assessment are developing rapidly, and over time some of the key technical issues that remain are likely to be resolved. At the same time, there are several other issues that have to be addressed. One is the necessity of communities starting to take centre stage in conducting vulnerability analysis and implementation to enhance their long-term capacities for adaptation. Another is the organisational changes that are needed to face the threat that climate change poses to development: climate change is inevitable, and it will add burdens to those who are already poor and vulnerable. A third issue is that Africa appears to have some of the greatest burdens of climate change impacts, certainly from the human health and agricultural perspectives; it is a region with generally limited ability to cope and adapt; and it has some of the lowest per capita emissions of the greenhouse gases that contribute to global warming. The likely impacts of climate change thus present a global ethical challenge as well as a development and scientific challenge, and this challenge has to be addressed by all of us