88,341 research outputs found

    Solid waste management in Puerto Rico : an assessment of environmental impacts and benefits

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    Municipal solid waste (MSW) management has been a challenging issue throughout history. Waste management options have evolved, but they can present distinct environmental impacts, such as the emission of greenhouse gases (GHG). This study quantified the environmental benefits (i.e., greenhouse gas emission and energy use reductions) of various MSW management plans proposed for Puerto Rico through the use of the Waste Reduction Model (WARM). The waste management initiative known as the “Base Case” was found to offer the most environmental benefits. Thus, higher benefits can be attained from the implementation of an integrated solid waste managementDepartment of Natural Resources and Environmental ManagementThesis (M.S.

    A U(1) non-universal anomaly-free model with three Higgs doublets and one singlet scalar field

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    The flavor problem, neutrino physics and the fermion mass hierarchy are important motivations to extend the Standard Model into the TeV scale. A new family non-universal extension is presented with three Higgs doublets, one Higgs singlet and one scalar dark matter candidate. Exotic fermions are included in order to cancel chiral anomalies and to allow family non-universal U(1)X\mathrm{U(1)}_{X} charges. By implementing an additional Z2\mathbb{Z}_{2} symmetry the Yukawa coupling terms are suited in such a way that the fermion mass hierarchy is obtained without fine-tuning. The neutrino sector include Majorana fermions to implement inverse see-saw mechanism. The effective mass matrix for SM neutrinos is fitted to current neutrino oscillation data to check the consistency of the model with experimental evidence, obtaining that the normal-ordering scheme is preferred over the inverse ones and the values of the neutrino Yukawa coupling constants are shown. Finally, the hτμh\rightarrow \tau\mu lepton-flavor-violation process is addressed with the rotation matrices of the CP-even scalars, left- and right-handed charged leptons, yielding definite regions where the model is consistent with CMS reports of BR(hτμ)\mathrm{BR}(h\rightarrow \tau\mu). Keywords: Flavor Problem, Neutrino Physics, Extended Scalar Sectors, Beyond Standard Model, Fermion masses, Inverse See-Saw Mechanism, LFV.Comment: 18 pages, 3 figures, 4 tables, added reference

    Automatic Generation of Cognitive Theories using Genetic Programming

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    Cognitive neuroscience is the branch of neuroscience that studies the neural mechanisms underpinning cognition and develops theories explaining them. Within cognitive neuroscience, computational neuroscience focuses on modeling behavior, using theories expressed as computer programs. Up to now, computational theories have been formulated by neuroscientists. In this paper, we present a new approach to theory development in neuroscience: the automatic generation and testing of cognitive theories using genetic programming. Our approach evolves from experimental data cognitive theories that explain “the mental program” that subjects use to solve a specific task. As an example, we have focused on a typical neuroscience experiment, the delayed-match-to-sample (DMTS) task. The main goal of our approach is to develop a tool that neuroscientists can use to develop better cognitive theories

    Skinner-Rusk approach to time-dependent mechanics

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    The geometric approach to autonomous classical mechanical systems in terms of a canonical first-order system on the Whitney sum of the tangent and cotangent bundle, developed by R. Skinner and R. Rusk, is extended to the time-dependent framework
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