4,274 research outputs found

    Linking rivers in the Ganges-Brahmaputra River Basin: exploring the transboundary effects

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    The following paper explores the possible inter-linkage of the Ganges and Brahmaputra River Basin and analyzes its effect on future water allocation between the upstream country, India, and the downstream country, Bangladesh. We find that water transfer from the Brahmaputra River could be mutually beneficial for both countries. However, the only possible motivation for the richer upstream country, India, to agree to transfer water to the poorer downstream country, Bangladesh, is political altruism. Using a political economy model we find that, if there is a good political relationship between India and Bangladesh, then India could be altruistic toward Bangladesh and transfer more water downstream. Changes in political altruism factor, however, could entice India to exercise unilateral diversion, in which case simulations predict that Bangladesh would incur large environmental damages. Political uncertainty may also result in unilateral diversion of water by India, and could prevent agreement on water transfers from the Brahmaputra. We therefore explore the conditions under which Bangladesh could accept an Indian proposal to transfer water from Brahmaputra, despite political uncertainty.Length: pp.373-395River basin managementRiver basin developmentDevelopment projectsInternational cooperationWater transferWater allocationPlanningFlowSimulation modelsComputer softwareEnvironmental effectsRisks

    The importance of habitat quality for marine reserve fishery linkages

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    We model marine reserve - fishery linkages to evaluate the potential contribution of habitat-quality improvements inside a marine reserve to fish productivity and fishery catches. Data from Mombasa Marine National Park, Kenya, and the adjacent fishery are used. Marine reserves increase total fish biomass directly by providing refuge from exploitation and indirectly by improving fish habitat in the reserve. As natural mortality of the fish stock decreases in response to habitat enhancement in the reserve, catches increase by up to 2.6 tonnes (t).km(-2).year(-1) and total fish biomass by up to 36 t.km(-2). However, if habitat-quality improvement reduces the propensity of fish to move out of the reserve, catches may fall by up to 0.9 t.km(-2).year(-1). Our results indicate that habitat protection in reserves can underpin fish productivity and, depending on its effects on fish movements, augment catches

    HIV-1 Evolutionary Patterns Associated with Metastatic Kaposi's Sarcoma during AIDS.

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    Kaposi's sarcoma (KS) in HIV-infected individuals can have a wide range of clinical outcomes, from indolent skin tumors to a life-threatening visceral cancer. KS tumors contain endothelial-related cells and inflammatory cells that may be HIV-infected. In this study we tested if HIV evolutionary patterns distinguish KS tumor relatedness and progression. Multisite autopsies from participants who died from HIV-AIDS with KS prior to the availability of antiretroviral therapy were identified at the AIDS and Cancer Specimen Resource (ACSR). Two patients (KS1 and KS2) died predominantly from non-KS-associated disease and KS3 died due to aggressive and metastatic KS within one month of diagnosis. Skin and visceral tumor and nontumor autopsy tissues were obtained (n = 12). Single genome sequencing was used to amplify HIV RNA and DNA, which was present in all tumors. Independent HIV tumor clades in phylogenies differentiated KS1 and KS2 from KS3, whose sequences were interrelated by both phylogeny and selection. HIV compartmentalization was confirmed in KS1 and KS2 tumors; however, in KS3, no compartmentalization was observed among sampled tissues. While the sample size is small, the HIV evolutionary patterns observed in all patients suggest an interplay between tumor cells and HIV-infected cells which provides a selective advantage and could promote KS progression

    Circumstellar environment of RX Puppis

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    The symbiotic Mira, RX Pup, shows long-term variations in its mean light level due to variable obscuration by circumstellar dust. The last increase in extinction towards the Mira, between 1995 and 2000, has been accompanied by large changes in the degree of polarization in the optical and red spectral range. The lack of any obvious associated changes in the position angle may indicate the polarization variations are driven by changes in the properties of the dust grains (e.g. variable quantity of dust and variable particle size distribution, due to dust grain formation and growth) rather than changes in the viewing geometry of the scattering region(s), e.g. due to the binary rotation.Comment: Paper presented at Torun 2000 conference on Post-AGB objects as a phase of stellar evolution; 8 pages, 3 figure
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