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This analysis of a backward integration traceability scheme for red chillies developed by a multinational food company in India emphasizes spatial integration and differentiation within contract farming. The scheme is premised on the procurement of identically credentialed produce from 10 different sites in two states and incorporates growers in highly flexible and place‐contingent modes. Interviews with corporate informants and farmers reveal this flexibility to be the result of a two‐way process of risk management between the company and growers. The company spread its geographical exposure by initiating production across a number of far‐flung cultivation sites, and growers cultivate chillies for the company within the context of diverse agricultural systems, thereby mitigating dependence. The scheme has had positive impacts for participants, but has more complex implications for the evolution of agrarian landscapes in India. The selective enrolment of participants through ‘progressive farmer’ networks acts to reorganize rural spaces by generating new geographies of advantage and opportunity.  相似文献   
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Controls on the carbon isotopic signatures of methanotroph biomarkers have been further explored using cultured organisms. Growth under conditions which select for the membrane-bound particulate form of the methane monooxygenase enzyme (pMMO) leads to a significantly higher isotopic fractionation than does growth based on the soluble isozyme in both RuMP and serine pathway methanotrophs; in an RuMP type the delta delta 13Cbiomass equaled -23.9% for pMMO and -12.6% for sMMO. The distribution of biomarker lipids does not appear to be significantly affected by the dominance of one or the other MMO type and their isotopic compositions generally track those of the parent biomass. The 13C fractionation behaviour of serine pathway methanotrophs is very complex, reflecting the assimilation of both methane and carbon dioxide and concomitant dissimilation of methane-derived carbon. A limitation in CH4 availability leads to the production of biomass which is 13C-enriched with respect to both carbon substrates and this occurs irrespective of MMO type. This startling result indicates that there must be an additional fractionation step downstream from the MMO reaction which leads to incorporation of 13C-enriched carbon at the expense of dissimilation of 13C-depleted CO2. In these organisms, polyisoprenoid lipids are 13C-enriched compared to polymethylenic lipid which is the reverse of that found in the RuMP types. Serine cycle hopanoids, for example, can vary anywhere from 12% depleted to 10% enriched with respect to the CH4 substrate depending on its concentration. Decrease in growth temperature caused an overall increase in isotopic fractionation. In the total biomass, this effect tended to be masked by physiological factors associated with the type of organism and variation in the bulk composition. The effect was, however, clearly evident when monitoring the 13C signature of total lipid and individual biomarkers. Our results demonstrate that extreme carbon isotopic depletion in field samples and fossil biomarker lipids can be indicative of methanotrophy but the converse is not always true. For example, the hopanoids of a serine cycle methanotroph may be isotopically enriched by more than 10% compared to the substrate methane when the latter is limiting. In other words, hopanoids from some methanotrophs such as M. trichosporium would be indistinguishable from those of cyanobacteria or heterotrophic bacteria on the basis of either chemical structure or carbon isotopic signature.  相似文献   
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An annual whiting event occurs each year in late May to early June in Fayetteville Green Lake, New York. The initiation of this event correlates with exponential growth of the Synechococcus population within the lake. Synechococcus is the dominant (by approximately 4 orders of magnitude) autotrophic organism owing to the oligotrophic condition of the lake. The delta 13C values of the dissolved inorganic C range seasonally from -9.5% in winter to -6.2% in summer due to photosynthetic activity. Calcite precipitates principally in the microenvironment surrounding Synechococcus because of a photosynthetically driven alkalization process and the availability of the cells as nucleation sites. This calcite has a heavier delta 13C value (>4%) than does the dissolved inorganic C of the lake water owing to the cells' preferential uptake of 12C. A conceptual model suggests that photosynthetic activity and cell surface chemistry, together with the substantial surface area that arises from the great abundance of micron-sized cells, allow Synechococcus to dominate the annual whiting events in Fayetteville Green Lake.  相似文献   
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The Human Development Report 2007/8 (HDR) and the World Development Report 2010 (WDR) are both devoted to the connections between climate change and development. The reports provide very different perspectives on where the key challenges reside. Their policy proposals are also different, but much less so. Using a combination of frame and content analysis complemented with attention to how these institutions and their knowledge production processes operate, the paper develops a structured comparison of the problem-framing and solution-framing in the Overviews of the two reports. It compares the reports’ conceptions of development; their normative content and the roles given to human rights; the pathways and solutions the agencies defend, and how protective they are of the poor; the status given to proposed market solutions; what types of information and expert perspective are prioritized and why, and which issues are neglected. Following its stress on human rights and ethical principles, the HDR does not unsettle the market driven solutions to climate change that dominate the global policy arena. Different policy instruments and a fuller institutionalization of its human rights concerns is required, in organizations, processes, methodologies and knowledge networks that could move the ideas forward and continually press for their use. This may require a different model of report preparation.  相似文献   
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Using studies of places where heat waves are common, projected changes in heat waves in Metro Vancouver are assessed from a multi-disciplinary perspective with respect to the potential impacts of the physical change on the people and infrastructure with the intention of being better prepared for future events. Trends in maximum temperature parameters for Metro Vancouver for the past 75 years are generally not statistically significant; however, projections for 2041–2060 and 2081–2100 suggest that the region will experience such events more frequently in the future due to climate change. While Metro Vancouver, British Columbia (BC) generally does not typically experience heat waves it was strongly affected by a major heat event in July 2009, with temperature records being broken at Vancouver (≥31 °C) on the coast and at Abbotsford (≥36 °C) 65-km inland. A lack of sea breeze during this event meant that there was no cooling effect, and land surface temperatures over the downtown area approached 40 °C and excess deaths occurred. Many victims were either in the 65–74 age category, the vulnerable poor, or people with mental health issues. Because these events are rare, many buildings lack air-conditioning, and residents of Metro Vancouver under-anticipate their vulnerability. The costs of health-related impacts outweighed those related to higher electricity usage.  相似文献   
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Statelessness, displacement and exile, far from being particular moments in history, continue to affect the lives of Palestinians living in Sydney, in the maintenance of national identity and community formation. The impacts that displacement and subsequent ‘statelessness’ have had on the ways in which Palestinians maintain a sense of national identity have similarities with those of other ‘displaced’ peoples. Without the recognition of national boundaries to secure national sovereignty (Palestine) and accommodate the continuation of a shared and inherited history, the most significant element through which Palestinian identity is kept ‘alive’ is the one thing that all Palestinians share: a communal sense of injustice which involves being denied the right to live in, or return to, their homeland. Statelessness, nationalism and the now ‘imagined community’ of Palestine are more crucial for Palestinians living in Sydney than more primordial elements of identity, such as language or local community. Statelessness and exile in Australia have constructed a particular sense of Palestinian nationalism. The continuity of Palestinian identity as a primarily political phenomenon is a situation analogous to that of other diasporic refugee communities.  相似文献   
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A prototype two-dimensional finite element flow model for depth-averaged free surface flows was developed for floodplain environments. Limited refinement of the model's physical representation was undertaken and the enhanced scheme applied to an 11 km river channel/floodplain reach in the U.K. Preliminary model results indicate that this modelling approach can be used to identify dynamic variations in the flow field parameters over length scales of the order of 10-100 m. Potentially, such data have the ability to permit detailed analysis of short-term floodplain sedimentary dynamics.  相似文献   
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