102 research outputs found

    Rice Intensification in a Changing Environment: Impact on Water Availability in Inland Valley Landscapes in Benin

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    This study assesses the impact of climate change on hydrological processes under rice intensification in three headwater inland valley watersheds characterized by different land conditions. The Soil and Water Assessment Tool was used to simulate the combined impacts of two land use scenarios defined as converting 25% and 75% of lowland savannah into rice cultivation, and two climate scenarios (A1B and B1) of the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios. The simulations were performed based on the traditional and the rainfed-bunded rice cultivation systems and analyzed up to the year 2049 with a special focus on the period of 2030–2049. Compared to land use, climate change impact on hydrological processes was overwhelming at all watersheds. The watersheds with a high portion of cultivated areas are more sensitive to changes in climate resulting in a decrease of water yield of up to 50% (145 mm). Bunded fields cause a rise in surface runoff projected to be up to 28% (18 mm) in their lowlands, while processes were insignificantly affected at the vegetation dominated-watershed. Analyzing three watersheds instead of one as is usually done provides further insight into the natural variability and therefore gives more evidence of possible future processes and management strategie

    Physically-based modelling of hydrological processes in a tropical headwater catchment (West Africa) ? process representation and multi-criteria validation

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    International audienceThe aim of the study was to test the applicability of a physically-based model to simulate the hydrological processes in a headwater catchment in Benin. Field investigations in the catchment have shown that lateral processes such as surface runoff and interflow are most important. Therefore, the 1-D SVAT-model SIMULAT was modified to a semi-distributed hillslope version (SIMULAT-H). Based on a good database, the model was evaluated in a multi-criteria validation using discharge, discharge components and soil moisture data. For the validation of discharge, good results were achieved for dry and wet years. The main differences were observable in the beginning of the rainy season. A comparison of the discharge components determined by hydro-chemical measurements with the simulation revealed that the model simulated the ratio of groundwater fluxes and fast runoff components correctly. For the validation of the discharge components of single events, larger differences were observable, which was partly caused by uncertainties in the precipitation data. The representation of the soil moisture dynamics by the model was good for the top soil layer. For deeper soil horizons, which are characterized by higher gravel content, the differences between simulated and measured soil moisture were larger. A good agreement of simulation results and field investigations was achieved for the runoff generation processes. Interflow is the predominant process on the upper and the middle slopes, while at the bottom of the hillslope groundwater recharge and ? during the rainy season ? saturated overland flow are important processes

    An interdisciplinary scenario analysis to assess the water availability and water consumption in the Upper Ouémé catchment in Benin

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    This paper presents an interdisciplinary scenario analysis to assess the influence of global and regional change on future water availability and water consumption in the Upper Ouémé catchment in central Benin. For the region three development scenarios were evolved. These scenarios are combined with climate change scenarios based on the IPCC (Intergovernmental Panel on Climate Change). In the mo-delling approach the quantification of the land use/land cover change is performed by the cellular automata model CLUE-S. The future climate scenarios are computed with the regional climate model REMO driven by the global ECHAM model. Using this data different land use and climate change scenarios can be calculated with the conceptual hydrological model UHP-HRU to assess the effects of global changes on the future water availability in Benin. <P> To analyse the future water availability also the water consumption has to be taken into account. Due to high population growth an increase in water need in the future is expected for the region. To calculate the future household water consumption data from a regional survey and demographic projections are used. Development of the water need for animal husbandry is also considered. <P> The first test run of the modelling approach was performed for the development scenario &apos;business as usual&apos; combined with the IPCC scenario B2 for the year 2025. This test demonstrates the applicability of the approach for an interdisciplinary scenario analysis. A continuous run from 2000&ndash;2025 will be simulated for different scenarios as soon as the input data concerning land use/land cover and climate are available

    IMPETUS: Implementing HELP in the Upper Ouémé basin

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    Regional climate models that take into account land-use changes indicate that in the future, a general decrease in rainfall, together with prominent surface heating, can be expected for sub-Saharan Africa and the region north of the Sahara until 2050. Due to high population growth, land use changes rapidly and influences water availability and water demand. In this context, the research project IMPETUS (‘An Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa’) offers a range of options for sustainable management of different components of the hydrological cycle. Target areas are the OuĂ©mĂ© basin in Benin and the DrĂąa catchment in Morocco. This paper concentrates on the OuĂ©mĂ© basin.Based on plausible scenarios of future economic, demographic, and climate developments, the effects of land use, land cover change, climate change, and demographic development on water availability and water demand are quantified. Scenarios of future water availability and water demand for the Upper OuĂ©mĂ© (Benin) catchment are discussed. To calculate water availability, the output of a regional climate model was linked to a hydrological model that also considered land use change calculated by a cellular automata model. Future water requirements were computed by linking population growth and per capita water demand, which was derived from a regional survey. Furthermore, the need for water for animal husbandry was considered.The results of the ‘business as usual’ scenario, combined with IPCC Scenarios A1B and B2, through the year 2045 are presented. The results reveal a significant decrease in water availability (surface water and groundwater) due to a decrease in rainfall and a significant increase in evapotranspiration. Although total water consumption increases strongly, it represents only about 0.5% of the yearly renewable water resources. Comparing these data, it may be concluded that water scarcity is not a problem in Benin. However, water availability shows high temporal variations due to the rainy and the dry seasons. Even if physical water scarcity is not a limiting factor, access to water in some parts of the catchment is limited due to economic factors.Keywords: HELP, IMPETUS, Benin, Morocco, Decision Support Systems, global change, information systems, loosely coupled models, problem clusters, scenario development, water availability, water deman

    Asymptomatic Right Atrial Thrombosis After Acute Lymphoblastic Leukemia Treatment

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    Right atrial thrombosis is a rare, but potentially serious complication of acute lymphoblastic leukemia treatment. We conducted a retrospective multicenter study to assess the incidence, treatment, and outcome of asymptomatic right atrial thrombosis detected at routine echocardiography of children after acute lymphoblastic leukemia treatment in the Nordic and Baltic countries. Eleven (2.7%, 95% confidence interval, 1.4-4.9) of 406 patients had asymptomatic right atrial thrombosis, ranging from 10 to 25 mm at detection. Three patients were treated with anticoagulation. None of the thromboses affected cardiac function, and they showed neither sign of progress nor spontaneous or treatment-related regress at follow-up.Peer reviewe

    Impact of Chlamydia trachomatis in the reproductive setting: British Fertility Society Guidelines for practice

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    Chlamydia trachomatis infection of the genital tract is the most common sexually transmitted infection and has a world-wide distribution. The consequences of infection have an adverse effect on the reproductive health of women and are a common cause of infertility. Recent evidence also suggests an adverse effect on male reproduction. There is a need to standardise the approach in managing the impact of C. trachomatis infection on reproductive health. We have surveyed current UK practice towards screening and management of Chlamydia infections in the fertility setting. We found that at least 90% of clinicians surveyed offered screening. The literature on this topic was examined and revealed a paucity of solid evidence for estimating the risks of long-term reproductive sequelae following lower genital tract infection with C. trachomatis. The mechanism for the damage that occurs after Chlamydial infections is uncertain. However, instrumentation of the uterus in women with C. trachomatis infection is associated with a high risk of pelvic inflammatory disease, which can be prevented by appropriate antibiotic treatment and may prevent infected women from being at increased risk of the adverse sequelae, such as ectopic pregnancy and tubal factor infertility. Recommendations for practice have been proposed and the need for further studies is identified

    Development and analysis of the Soil Water Infiltration Global database.

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    In this paper, we present and analyze a novel global database of soil infiltration measurements, the Soil Water Infiltration Global (SWIG) database. In total, 5023 infiltration curves were collected across all continents in the SWIG database. These data were either provided and quality checked by the scientists who performed the experiments or they were digitized from published articles. Data from 54 different countries were included in the database with major contributions from Iran, China, and the USA. In addition to its extensive geographical coverage, the collected infiltration curves cover research from 1976 to late 2017. Basic information on measurement location and method, soil properties, and land use was gathered along with the infiltration data, making the database valuable for the development of pedotransfer functions (PTFs) for estimating soil hydraulic properties, for the evaluation of infiltration measurement methods, and for developing and validating infiltration models. Soil textural information (clay, silt, and sand content) is available for 3842 out of 5023 infiltration measurements (~76%) covering nearly all soil USDA textural classes except for the sandy clay and silt classes. Information on land use is available for 76% of the experimental sites with agricultural land use as the dominant type (~40%). We are convinced that the SWIG database will allow for a better parameterization of the infiltration process in land surface models and for testing infiltration models. All collected data and related soil characteristics are provided online in *.xlsx and *.csv formats for reference, and we add a disclaimer that the database is for public domain use only and can be copied freely by referencing it. Supplementary data are available at https://doi.org/10.1594/PANGAEA.885492 (Rahmati et al., 2018). Data quality assessment is strongly advised prior to any use of this database. Finally, we would like to encourage scientists to extend and update the SWIG database by uploading new data to it

    Linking Climate Change and Groundwater

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    MIGRATION ELASTICITIES, FISCAL FEDERALISM, AND THE ABILITY OF STATES TO REDISTRIBUTE INCOME

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    Since at least Musgrave (1971) and Oates (1972), it has been argued that tax-induced migration severely hinders state attempts at redistribution, and this function of government should thus be administered at the federal level. Nevertheless, states continue to engage in redistribution. Furthermore, results from recent research on the relationship between taxes and migration are mixed, with some studies suggesting that tax-induced migration may be fairly small. Additionally, even if state-level redistribution is less effective than federal action, a role for state governments may remain if tastes for redistribution vary substantially across states. This paper develops a simulation model that is used to examine the effectiveness of state attempts at redistribution under a variety of migration elasticity assumptions. Key outputs from the simulation include the impact of tax-induced migration on state revenues, excess burden, and fiscal externalities. With modest migration elasticities, the costs of state-level redistribution are substantial, but state action may still be preferred to a federal policy that is at odds with preferences of a state’s citizens. At higher migration elasticities, the costs of state action can be tremendous. Overall excess burden is greater, but this is dominated by horizontal fiscal externalities. Horizontal fiscal externalities represent a cost to the state pursuing additional redistribution, but not a cost at the national level. For example, with a migration elasticity of 0.3, a 3 percent surtax increases overall excess burden by just 1 percent (compared to a case where the federal government implements the identical policy). However, because of horizontal fiscal externalities, the welfare loss to the state imposing the surtax increases by 18 percent. For higher surtaxes and higher migration elasticities, these effects are magnified. With a 10 percent surtax, overall excess burden rises by 8 percent (again compared to identical federal policy) and the burden borne by the state imposing the surtax rises by 43 percent. With a migration elasticity of 1, these numbers roughly double. The Institute for the Study of Labor (IZA) Discussion Paper version (August 2012) is attached below as an Additional file
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