1,119 research outputs found

    WHO OWNS THE WATER? A CASE STUDY OF EL PASO DEL NORTE

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    This paper, first, reviews the report filed by the Western Water Policy Review Advisory Commission since it touches on all the major issues associated with water rights and uses in the Upper Rio Grande Basin, defined as that part of the river from the San Luis Valley in Colorado to Fort Quitman, Texas. Second, the paper reviews historical developments over water use and water rights and briefly discusses the major characteristics of El Paso del Norte that do and will have an impact on water supply and consumption. Then the paper reviews the positions of the major stakeholders in the Basin, paying particular attention to their legal arguments. Finally, the paper attempts to describe the possible alternative outcomes of the continuing struggle over water.Water rights--Rio Grande Valley, Water supply--Management --Texas--Lower Rio Grande Valley, Water supply--Management--Mexico--Rio Grande Valley, Resource /Energy Economics and Policy,

    Worker flows, job flows and establishment wage differentials : analyzing the case of France

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    We address the relation between establishment wage differentials and worker flows, i.e. the churning rate and the quit rate. Our analysis is based on a linked employer-employee dataset covering the French private non-farm sector from 2002 to 2005. Our estimations support the hypothesis that wage premium is an efficient human resource management tool to stabilize workers : churning rates are lower in high-paying firms due to lower quit rates. We further show that the relation is not linear, and it differs among skill groups and according to establishment size : it is strongest for low-wage levels, for low-skilled workers and in large establishments.Establishment wage effects, worker flows, churning rate, quite rate, linked employer-employee panel data, France.

    An `Analytic Dynamical Magnetosphere' formalism for X-ray and optical emission from slowly rotating magnetic massive stars

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    Slowly rotating magnetic massive stars develop "dynamical magnetospheres" (DM's), characterized by trapping of stellar wind outflow in closed magnetic loops, shock heating from collision of the upflow from opposite loop footpoints, and subsequent gravitational infall of radiatively cooled material. In 2D and 3D magnetohydrodynamic (MHD) simulations the interplay among these three components is spatially complex and temporally variable, making it difficult to derive observational signatures and discern their overall scaling trends.Within a simplified, steady-state analysis based on overall conservation principles, we present here an "analytic dynamical magnetosphere" (ADM) model that provides explicit formulae for density, temperature and flow speed in each of these three components -- wind outflow, hot post-shock gas, and cooled inflow -- as a function of colatitude and radius within the closed (presumed dipole) field lines of the magnetosphere. We compare these scalings with time-averaged results from MHD simulations, and provide initial examples of application of this ADM model for deriving two key observational diagnostics, namely hydrogen H-alpha emission line profiles from the cooled infall, and X-ray emission from the hot post-shock gas. We conclude with a discussion of key issues and advantages in applying this ADM formalism toward derivation of a broader set of observational diagnostics and scaling trends for massive stars with such dynamical magnetospheres.Comment: 15 pages, 11 figures, accepted for MNRA

    Optimization of Piezoelectric Electrical Generators Powered by Random Vibrations

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    This paper compares the performances of a vibrationpowered electrical generators using PZT piezoelectric ceramic associated to two different power conditioning circuits. A new approach of the piezoelectric power conversion based on a nonlinear voltage processing is presented and implemented with a particular power conditioning circuit topology. Theoretical predictions and experimental results show that the nonlinear processing technique may increase the power harvested by a factor up to 4 compared to the Standard optimization technique. Properties of this new technique are analyzed in particular in the case of broadband, random vibrations, and compared to those of the Standard interface.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    The duodenal mucosa in patients with renal failure: Response to 1,25(OH)2D3

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    The duodenal mucosa in patients with renal failure: Response to 1,25(OH)2D3. The structure of the duodenal mucosa was evaluated i n duodenal biopsy samples obtained from patients with moderate renal failure (MRF) and in dialysis patients (HD) in an effort to examine the possibility that changes in duodenal mucosa may contribute to the impaired calcium absorption in renal failure (RF). The effect of therapy with 1,25(OH)2D3 on the duodenal mucosa in the HD patients was also studied. The results show that both MRF and HD patients have reduction in calcium reabsorption and in the length of their intestinal villi and crypts of Lieberkuhn. In the HD patients, these structural changes were more severe. Treatment with 1,25(OH)2D3 produced significant improvement in calcium reabsorption (P < 0.01) as well as in length of villus and crypt (P < 0.02) and increased mitotic activity in the crypts (P < 0.02). Electron microscopy revealed the microvilli to be shorter, irregularly distributed, moth-eaten, and grainy, with these abnormalities disappearing after treatment. The data show that duodenal mucosa in RF exhibits structural abnormalities, which were normalized after 1,25(OH)2D3 therapy, and suggest that these derangements may play a role in the defective calcium reabsorption in RF.La muqueuse duodĂ©nale chez les malades en insuffisance rĂ©nale: RĂ©ponse au 1,25(OH)2D3. La structure de la muqueuse duodĂ©nale a Ă©tĂ© Ă©valuĂ©e sur des biopsies duodĂ©nales de malades atteints d'insuffisance rĂ©nale modĂ©rĂ©e (MFR) et de malades en hĂ©modialyse (HD) afin d'Ă©tudier l'hypothĂšse selon laquelle des modifications de la muqueuse duodĂ©nale pourraient contribuer Ă  l'altĂ©ration de l'absorption du calcium au cours de l'insuffisance rĂ©nale. L'effet du traitement par 1,25(OH)2D3 sur la muqueuse duodĂ©nale a Ă©tĂ© Ă©tudiĂ© chez les malades HD. Les rĂ©sultats montrent que les malades MRF et HD ont une diminution de l'absorption du calcium et de la longueur de leurs villositĂ©s intestinales et de leurs cryptes de Lieberkuhn. Chez les malades HD ces modifications de structure sont encore plus sĂ©vĂšres. Le traitement par 1,25(OH)2D3 dĂ©termine une amĂ©lioration significative de l'absorption du calcium (P < 0,01) de mĂȘme qu'une augmentation de la longueur des villositĂ©s et des cryptes (P < 0,02) et une augmentation de l'activitĂ© mitotique dans les cryptes (P < 0,02). La microscopie Ă©lectronique montre que les micro-villositĂ©s sont raccourcies, irrĂ©guliĂšrement distribuĂ©es et d'aspect mitĂ© et granuleux, anomalies qui disparaissent aprĂšs le traitement. Les rĂ©sultats montrent que la muqueuse duodĂ©nale des malades RF a des anomalies de structure qui sont normalisĂ©es au cours du traitement par 1,25(OH)2D3 et suggĂšrent que ces modifications peuvent jouer un rĂŽle dans le dĂ©ficit de au cours de RF

    A three-thousand-year history of vegetation and human impact in Burgundy (France) reconstructed from pollen and non-pollen palynomophs analysis

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    International audienceThis article presents a 241 cm long sediment record documenting the vegetation history using previous termpollen and non-pollennext term palynomorphs recovered from the FĂ©nay marsh in Burgundy (Dijon area – previous termFrance). The pollen and non-pollennext term palynomorphs (NPP) record largely reflects intensive human influence (clearing, cultivation and grazing) on the surrounding area from the Late Bronze Age and Hallstatt period. La TĂšne period is marked by drier conditions and a substantial increase in Alnus. During the Gallo-Roman period, high values of Alnus decrease to the benefit of Quercus. In the Early Middle Ages (5th–10th C), the swamp becomes a temporary pond and Cerealia type and Secale are cultivated in this very open landscape. During the Late Middle Ages (13th–15th C), the temporary pond is transformed into a larger and deeper pond, used by the Cistercians for hydraulic power and perhaps as a hemp-retting pit. By the end of the 16th C, the pond had dried out and was used for the cultivation of cereal
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