598 research outputs found

    International law and transboundary dams: lessons learned from the Binational Entity ITAIPU (Brazil and Paraguay)

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    The international river Paraná flows through Brazil, Paraguay and Argentina, and holds two major binational dams: the upstream ITAIPU dam (Brazil-Paraguay) and the downstream Yacyreta dam (Argentina-Paraguay). In the past years, the South American region was strongly affected by adverse environmental challenges exacerbated by climate change, like wildfires and severe droughts, which in turn drastically affected the water flow of the Paraná river, a river used for multiple purposes, inter alia the production of energy. The hydropower obtained from ITAIPU is one of the main sources of energy for Paraguay and the Southern part of Brazil. At the same time, the downstream parts of the river is used for navigation purposes, which is crucial for land-locked Paraguay to export its agricultural products, and for water consumption, as is the case for Argentina. The present case study will show how in spite of these challenges, South America has been an successful example of transboundary water cooperation, especially by using the international water law guidelines aimed at achieving reasonable and equitable utilization of an international river

    Active spheroids in viscosity gradients

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    In this paper, we explore the hydrodynamics of spheroidal active particles in viscosity gradients. This work provides a more accurate modeling approach, in comparison to spherical particles, for anisotropic organisms like Paramecium swimming through inhomogeneous environments, but more fundamentally examines the influence of particle shape on viscotaxis. We find that spheroidal squirmers generally exhibit dynamics consistent with their spherical analogs, irrespective of the classification of swimmers as pushers, pullers, or neutral swimmers. However, the slenderness of the spheroids tends to reduce the impact of viscosity gradients on their dynamics; when swimmers become more slender, the viscosity difference across their body is reduced, which leads to slower reorientation. We also derive the mobility tensor for passive spheroids in viscosity gradients generalizing previous results for spheres and slender bodies. This work enhances our understanding of how shape factors into the dynamics of passive and active particles in viscosity gradients, and offers new perspectives that could aid the control of both natural and synthetic swimmers in complex fluid environments.Comment: 19 pages, 5 figure

    Adapting watercourse agreements to developments in international law: the case of the Itaipu Treaty

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    - Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à Lei de Direitos Autorais, não disponibilizamos a obra na íntegra.- Localização na estante: 341.221.1(81+893) G995

    Evaluation of risk factors leading to soil destabilisation on the south coastal sandplain of Western Australia

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    The problems of wind erosion in part of the south coast of Western Australian sandplain area were described previously (Gorddard et al, 1981) with 7.3 per cent of cleared and 18.3 per cent of the cropped area showing evidence of sand blasting. Department of Agriculture trials have shown that the loss of the top four millimetres of top soil from pastured paddocks can reduce following crop yields by up to 20 per cent (Marsh and Carter, 1983). Animal production problems associated with wind erosion of soils have not been quantified, but a number of problems such as reduced carrying capacity and nutritional problems are seen as significant throughout the area. Farmer opinion suggests that high grazing pressures are a major contributing factor to wind erosion however Gorddard et al (1981) were unable to identify any empirical relationship between stocking rate, cropping practice and erosion risk

    Frequency control of photonic crystal membrane resonators by mono-layer deposition

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    We study the response of GaAs photonic crystal membrane resonators to thin film deposition. Slow spectral shifts of the cavity mode of several nanometers are observed at low temperatures, caused by cryo-gettering of background molecules. Heating the membrane resets the drift and shielding will prevent drift altogether. In order to explore the drift as a tool to detect surface layers, or to intentionally shift the cavity resonance frequency, we studied the effect of self-assembled monolayers of polypeptide molecules attached to the membranes. The 2 nm thick monolayers lead to a discrete step in the resonance frequency and partially passivate the surface.Comment: 3 pages, 4 figures, submitted to Appl. Phys. Let

    Deep seam and minesoil carbon sequestration potential of the South Wales Coalfield, UK

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    Combustion of coal for energy generation has been a significant contributor to increased concentrations of atmospheric carbon dioxide. It is of interest to evaluate the potential of former coalfields for mitigating these increases by carbon sequestration and to compare different options to achieving this end. Here, carbon sequestration in residual coal seams and through reclamation of spoil tips is compared, and their carbon dioxide storage potential in the South Wales Coalfield estimated. Coal seam sequestration estimates come from an established methodology and consider the total unmined coal resource below 500 m deep with potential for carbon sequestration. The most likely effective deep seam storage capacity is 104.9 Mt carbon dioxide, taking account of reservoir conditions and engineering factors. Whilst many spoil tips in South Wales have been reclaimed, the focus has not been on carbon sequestration potential. Estimates of minesoil restoration sequestration capacity were based on a survey of restored minesoil and vegetation carbon stocks, mainly on sites 20–30 years after restoration; data from this survey were then extrapolated to the coalfield as a whole. Minesoil storage is estimated at 1.5 or 2.5 Mt (+2.2 Mt in tree biomass) carbon dioxide based on average grassland or woodland measurements, respectively; modelled data predicted equilibrium values of 2.9 and 2.6 Mt carbon dioxide respectively in grassland or woodland minesoils. If all sites achieved close to the maximum capacity in their land use class, minesoil storage capacity would increase to 2.1 or 3.9 Mt carbon dioxide, respectively. Combining the best woodland minesoil and standing biomass values, sequestration capacity increases to 7.2 Mt carbon dioxide. The wider social, economic, environmental and regulatory constraints to achieving this sequestration for each approach are discussed. Coal seam sequestration has a much higher capacity but sequestration in mine sites is less costly and has fewer regulatory constraints. Findings indicate a significant combined potential for carbon sequestration in the South Wales Coalfield and highlight challenges in achieving this potential. On a global scale, ex-coalfield sequestration could contribute to broader efforts to mitigate emissions

    Survey of parasite control practices in sheep and cattle

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    Farms in the Albany, Esperance, Jerramungup and Katanning districts were surveyed to determine parasite control strategies currently used, to evaluate the adoption of recommended control practices and to detect areas of ineffective parasite control. For cattle, the number of drenches given in the low rainfall zone was higher than the number given in the high rainfall zone

    Identification of novel pesticides for use against glasshouse invertebrate pests in UK tomatoes and peppers

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    To inform current and future pesticide availability to glasshouse vegetable growers, the current project trialled more than twenty products, including existing industry standards, against four key pests of glasshouse tomatoes and bell peppers. These included experimental conventional chemical pesticides as well as alternative biopesticide and biorational products based on phytochemicals, microbials and physically-acting substances. The results suggest that certain biopesticide products, particularly botanicals, provide good levels of pest control, with the same being true of experimental conventional chemical pesticides not yet recommended for use against these pests on these crops. Efforts are on-going to ensure that results of the current project translate to industry benefit via new pesticide approvals

    Nonmyeloablative regimen preserves "niches" allowing for peripheral expansion of donor T-cells

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    AbstractT-cell recovery following myeloablative preparatory regimens and cord blood transplantation in adult patients gen erally occurs between 1 and 3 years following allogeneic bone marrow transplantation. T-cell reconstitution may involve thymic education of donor-derived precursors or peripheral expansion of mature T-cells transferred in the graft. We measured quantitative and qualitative immunologic reconstitution, T-cell receptor spectratyping, and T-cell receptor excision circle (TREC) levels in adult recipients of umbilical cord blood transplants following a novel nonmyeloablative regimen. These results were compared to previously published results of similar patients receiving a myeloablative regimen and cord blood stem cells. With small numbers of patients treated so far, T-cells (CD3+) reached normal levels in adults 6 to 12 months following nonmyeloablative transplantation compared with 24 months in adults receiving a myeloablative regimen. At 12 months after transplantation, the numbers of phenotypically naive (CD45RA) T-cells were higher in those receiving the nonmyeloablative regimen. The T-cell repertoire in cord blood recipients treated with a nonmyeloablative regimen was markedly more diverse and robust compared with the repertoire in those receiving the myeloablative regimen at similar time points. TRECs (which are generated within the thymus and identify new thymic emigrants and those that have not divided) were detected 12 months after transplantation in the nonmyeloablative recipients, whereas TRECs were not detected in adults until 18 to 24 months in those receiving myeloablative regimens. Thus, in adults receiving a nonmyeloablative preparatory regimen, the quantitative and qualitative recovery of T-cells occurs through rapid peripheral expansion. The ability of patients receiving a nonmyeloablative regimen to recover within a few months suggests that the peripheral niches in which T-cells can proliferate are preserved in these patients compared to those receiving ablative regimens. Moreover, the presence of TREC-positive cells within 1 year suggests that thymic recovery is likewise accelerated in non myeloablative compared to myeloablative regimens.Biol Blood Marrow Transplant 2002;8(5):249-56

    Camp and College Parallels: Crucibles for Transition-Linked Turning-Points

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    This conceptual paper explores how the system of experiences that children encounter in a traditional, residential summer camp setting parallel traditional, residential, college setting for first-year students. Camp is a complex system in the sphere of youth development programs (YDP) because of the expectation for rapid adjustment by the camper to a novel physical and social environment. Many YDPs have a moderate to high level of connection with the child’s normal life, defined as similar to school or home environments and the activities in which youth regularly participate. A traditional residential summer camp offers a different degree of novelty than most other YDP settings. This paper offers a list of physical elements present in a camp setting that parallel the college setting and considers common camp-college parallels to articulate connected physical, social, emotional, and intellectual domains. This integration of ideas illustrates how the socio-physical novelty of the camp experience serves as a crucible for rapid adjustment and multi-dimensional growth in a way that is uniquely different from many other youth development settings
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