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Disproportionately little attention has been paid to the dry season trade‐off between rice and (inland capture) fish production on the floodplains of Bangladesh, compared to the same trade‐off during the flood season. As the rural economy grows increasingly dominated by dry‐season irrigated rice production, and floodplain land and water come under ever‐increasing pressure during the dry winter months, there is an urgent need to focus attention on these dry months that are so critical to the survival and propagation of the floodplain resident fish, and to the poor people that depend on these fish for their livelihood. This article examines three important dry‐season natural resource constraints to floodplain livelihoods in Bangladesh, and finds a common factor at the heart of all three: rice cultivation on lands at low and very low elevations. The article articulates the system interlinkages that bind these constraints and the long‐run trend towards irrigated rice cropping on lower‐lying lands, and suggests a management approach based on locally tailored strategies to arrest this trend. Apart from its direct relevance to the floodplains of Bangladesh, which support more than 100 million people, these lessons have relevance for river floodplain systems elsewhere in the developing world, notably the Mekong Delta.  相似文献   
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Despite efforts to include residents in hazard management, their contributions are often undervalued because they are seen as passive recipients of intervention rather than active participants in the production of knowledge, particularly when they lack technical expertise. However, using multiple perspectives and experiences can improve hazard management strategies and create safer communities. This paper examines a Colombian landslide management program to highlight the prospects and limitations of incorporating non-expert knowledge into hazard management. The Guardianas de la Ladera (Guardians of the Slope) in Manizales, Colombia is a program in which female heads of household are hired to maintain landslide-prevention infrastructure and communicate landslide risk to the community. While the highly regarded program is perceived as having reduced the frequency of landslides and associated damages, the hierarchical institutional structure inhibits bottom-up communication, including information that could improve long-term vulnerability reduction. We argue that regardless of the location, scale, or specific hazard being addressed, incorporating non-expert knowledge into hazard management potentially illuminates sources of vulnerability not recognized by technical or development experts.  相似文献   
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<正>Introduction Cadmium is considered a human carcinogen by the International Agency for Research on Cancer(IARC,1993)and the US National Toxicology Program(NTP,1997).Cadmium contamination of food crops is a persistent issue for both the agricultural industry as well as consumers.This is an issue for agriculture because cadmium can be present in soils naturally or as a result of industrial processes and can contaminate foods that are consumed by humans.Industrial  相似文献   
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Controlling hydrogen sulfide(H2S) odors and emissions using a single,effective treatment across a town-scale sewer network is a challenge faced by many water utilities.Implementation of a sewer diversion provided the opportunity to compare the effectiveness of magnesium hydroxide(Mg(OH)2) and two biological dosing compounds(Bioproducts A and B),with different modes of action(MOA),in a field-test across a large sewer network.Mg(OH)2 increases sewer p H allowing su...  相似文献   
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Behavioural variation is known to occur between individuals of the same population competing for resources. Individuals also vary with respect to their boldness or shyness. An individuals position along the shy-bold axis may be defined as the extent to which it is willing to trade off potentially increased predation risks for possible gains in resources. Similarly, group living may be interpreted as a trade-off between anti-predatory tactics and foraging efficiency. The responses of three-spined sticklebacks (Gasterosteus aculeatus) were tested across four social contexts to assess relative boldness or shyness and to further examine whether their behaviour would be consistent within and between contexts. Individuals displayed consistent responses within and between the first two contexts: those individuals which resumed foraging rapidly after a simulated aerial predator attack also displayed low shoaling tendencies. Such fish were deemed to be bold, whilst those which displayed the converse behaviour, slow resumption of foraging and a high shoaling tendency, were deemed to be shy. In a third context, bold individuals out-competed shy conspecifics for food. Boldness was also positively correlated with growth over a 6-week period. The position adopted by an individual within a group is usually interpreted as a trade-off between predation risk and foraging efficiency—both are greater at the front of a mobile group. Bold individuals showed significantly stronger tendencies towards front positions than shy conspecifics. The results suggest that, contrary to some previous studies on other animals, bold or shy behaviour in sticklebacks is consistent between contexts.Communicated by T. Czeschlik  相似文献   
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Abstract

For over a century the development industry has been less than mindful of the laws of nature and ecology. Among the negative side effects of this development track is the accumulation of nutrients in our soils and water, and greenhouse gases in our atmosphere. There is already evidence that this increased concentration is going to fundamentally change our Earth's climate and natural environment beyond recognition and predictability. The two superstorms that struck the southern United States in 2005 are an indication of the strength and frequency with which similar disasters might afflict other communities in the future. The time for celebrating the small fixes and innovations of a few industry leaders is over. Global collaboration and collective will are needed now if we are to reshape the future of our planet. New tools, economic constructs and political awareness provide the impetus and wherewithal to take on this challenge.  相似文献   
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