2,310 research outputs found

    The hormones of invertebrates

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    Thesis (M.A.)--Boston University, 193

    Prison-Based Education and Re-Entry into the Mainstream Labor Market

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    We estimate the post-release economic effects of participation in prison-based General Educational Development (GED) programs using a panel of earnings records and a rich set of individual information from administrative data in the state of Florida. Fixed effects estimates of the impact of participating in the GED education program show post-release quarterly earnings gains of about 15 percent for program participants relative to observationally similar non-participants. We also show, however, that these earnings gains accrue only to racial/ethnic minority offenders and any GED-related earnings gains for this group seem to fade in the third year after release from prison. Estimates comparing offenders who obtained a GED to those who participated in GED-related prison education programs but left prison without a GED show no systematic evidence of an independent impact of the credential itself on post-release quarterly earnings.

    Future hydropower production in the Lower Zambezi under possible climate change influence

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    Hydropower is the most important energy source in Mozambique and many other countries in southern Africa. Substantial hydropower development is planned for the Lower Zambezi for the next decades, with regional importance due to integration into the Southern African Power Pool. For such a long-term development, the possible impact of climate change on the future production is of essential interest. The objective of the presented study is to assess hydropower generation in the 21st century for a future hydropower development scenario under two climate scenarios. The two climate scenarios represent a future wetting climate and a future drying climate, both with considerable warming, and are based on bias-corrected data of two recent Global Climate Models. All hydro-meteorological input data are publicly available from an online decision support system, the Zambezi DSS. The future hydropower scenario considers the extension of the existing Cahora Bassa plant and three planned facilities downstream, Mphanda Nkuwa, Boroma and Lupata. Hydropower modelling for this cascade of reservoirs and hydropower plants is carried out with the HEC-ResSim model. Modelling results show a strong impact of precipitation projections on simulated future hydropower generation. With a wetting climate scenario, a marked increase of hydropower production of +11% for a near-future period (2021ā€“2050) and +9% for a far-future period (2071-2100) are projected, as compared with simulation results for a historic reference scenario. In a drying climate, hydropower generation decreases by -6% (near future) and -13% (far future). The climate change impact is stronger for the large extended Cahora Bassa plant than for the smaller downstream facilities. The results show the importance of considering climate risk in technical design and financial assessment of hydropower projects in the region.Keywords: Zambezi River, hydropower development, climate change, hydropower modelling, water resource

    The use of high-resolution terrain data in gravity field prediction

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    Different types of gravity prediction methods for local and regional gravity evaluation are developed, tested, and compared. Four different test areas were particularly selected in view of different prediction requirements. Also different parts of the spectrum of the gravity field were considered

    Support Vector Machine in Prediction of Building Energy Demand Using Pseudo Dynamic Approach

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    Building's energy consumption prediction is a major concern in the recent years and many efforts have been achieved in order to improve the energy management of buildings. In particular, the prediction of energy consumption in building is essential for the energy operator to build an optimal operating strategy, which could be integrated to building's energy management system (BEMS). This paper proposes a prediction model for building energy consumption using support vector machine (SVM). Data-driven model, for instance, SVM is very sensitive to the selection of training data. Thus the relevant days data selection method based on Dynamic Time Warping is used to train SVM model. In addition, to encompass thermal inertia of building, pseudo dynamic model is applied since it takes into account information of transition of energy consumption effects and occupancy profile. Relevant days data selection and whole training data model is applied to the case studies of Ecole des Mines de Nantes, France Office building. The results showed that support vector machine based on relevant data selection method is able to predict the energy consumption of building with a high accuracy in compare to whole data training. In addition, relevant data selection method is computationally cheaper (around 8 minute training time) in contrast to whole data training (around 31 hour for weekend and 116 hour for working days) and reveals realistic control implementation for online system as well.Comment: Proceedings of ECOS 2015-The 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems , Jun 2015, Pau, Franc

    Continuous image distortion by astrophysical thick lenses

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    Image distortion due to weak gravitational lensing is examined using a non-perturbative method of integrating the geodesic deviation and optical scalar equations along the null geodesics connecting the observer to a distant source. The method we develop continuously changes the shape of the pencil of rays from the source to the observer with no reference to lens planes in astrophysically relevant scenarios. We compare the projected area and the ratio of semi-major to semi-minor axes of the observed elliptical image shape for circular sources from the continuous, thick-lens method with the commonly assumed thin-lens approximation. We find that for truncated singular isothermal sphere and NFW models of realistic galaxy clusters, the commonly used thin-lens approximation is accurate to better than 1 part in 10^4 in predicting the image area and axes ratios. For asymmetric thick lenses consisting of two massive clusters separated along the line of sight in redshift up to \Delta z = 0.2, we find that modeling the image distortion as two clusters in a single lens plane does not produce relative errors in image area or axes ratio more than 0.5%Comment: accepted to GR
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