369 research outputs found

    Higgs Couplings without the Higgs

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    The measurement of Higgs couplings constitute an important part of present Standard Model precision tests at colliders. In this article, we show that modifications of Higgs couplings induce energy-growing effects in specific amplitudes involving longitudinally polarized vector bosons, and we initiate a novel program to study these very modifications of Higgs couplings off-shell and at high-energy, rather than on the Higgs resonance. Our analysis suggests that these channels are complementary and, at times, competitive with familiar on-shell measurements; moreover these high-energy probes offer endless opportunities for refinements and improvements.Comment: 7 pages, 5 figures. v2: Matches PRL published version, and includes additional materia

    Explaining Nonlinearities in Black Hole Ringdowns from Symmetries

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    It has been recently pointed out that nonlinear effects are necessary to model the ringdown stage of the gravitational waveform produced by the merger of two black holes giving rise to a remnant Kerr black hole. We show that this nonlinear behaviour is explained, both on the qualitative and quantitative level, by near-horizon symmetries of the Kerr black hole within the Kerr/CFT correspondence.Comment: 5 page

    La realidad virtual como entorno fortalecedor para el cambio personal: la contribuciĂłn del laboratorio de tecnologĂ­a aplicada a la neuropsicologĂ­a

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    When we exercise real choice, we gain increased control over our lives and are able to change ourselves. However for many subjects it is not easy to exercise effective choices: patients often don’t have the knowledge, skills, assertiveness, or self esteem needed. In this situation Virtual Reality (VR), an artificial reality that projects the user into a 3D space generated by the computer, may offer a critical advantage to the therapist. The enriched experience and the total level of control on its features, transform VR in an “empowering environment”, where patients can start to explore and act without feeling actually threatened. The attempt of defining, developing and testing VR tools supporting personal empowerment is the main goal of the Applied Technology for Neuro-Psychology Laboratory –ATN-P Lab– at the Istituto Auxologico Italiano. The paper describes the actual work done by the ATN-P Lab. in this area. Specifically, the open source "NeuroVR" system and its potential clinical applications –anxiety disorders, obesity and eating disorders– are presented and discussed.La capacidad de elección nos proporciona control sobre nuestras vidas y nos ofrece posibilidades de cambio. Sin embargo, para muchas personas no es fácil realizar elecciones efectivas; por ejemplo, los pacientes carecen muchas veces del conocimiento, la habilidad, la asertividad o autoestima necesarias. En esas situaciones, la realidad virtual (RV), una realidad artificial que coloca al sujeto en un espacio generado por el ordenador, puede ser para el terapeuta un recurso decisivo. La experiencia enriquecida y el control total sobre todos sus aspectos transforman la RV en un “entorno fortalecedor”, en el que los pacientes pueden comenzar a explorar y actuar sin sentirse amenazados. El principal objetivo del “Applied Technology for Neuro-Psychology Laboratory” (ATN-P Lab), perteneciente al Instituto Auxologico Italiano, es intentar definir, desarrollar y probar aplicaciones basadas en RV que faciliten el fortalecimiento personal. En este artículo se describe el trabajo que se viene realizando sobre este tema en ese laboratorio. Se presenta y discute, específicamente, el sistema de código abierto denominado “NeuroVR”, así como sus aplicaciones clínicas potenciales sobre los trastornos de ansiedad, la obesidad y los trastornos alimentarios

    Modelling of a safety relief valve through a MATLAB-Simulink and CFD based approach

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    The aim of the work is to understand the proper way to address the design and optimization procedures of a hydraulic safety relief valve. These valves are a part of the hydraulic circuit of many aircraft models, so their performances must be adapted to the specific system or engine. The only real constraints are the geometrical dimensions and the need to limit the weight of the device. This work requires gathering all the possible information available in the literature, and condensing them in a set of operations that will allow to promptly manufacture a product fitting the requirements needed. This should lead to the reduction of the amount of physical prototypes needed to obtain testing devices. The process studied uses a numerical fluid dynamic calculation approach to define the pressure field inside the valve and the forces acting on it, together with a Computational Fluid Dynamic (CFD) calculation used to identify the force distribution inside the valve. The first step deals with the creation of a CAD model of the valve. Then the CAD is imported into the CFD software, which evaluates the pressure field required to calculate the forces acting on the poppet of the valve. After the numerical scheme has been calibrated, some investigations are done to reduce the computational cost: the final goal is to run a complete simulation (meshing and solving) on a standard (even if high-end) laptop or desktop PC. Some of the positions (i.e. strokes) of the valve have been simulated as static, so a steady-state condition has been applied to solve the motion field. The main result consists of creating a MATLAB-SimulinkÂź model capable to reach results comparable to that obtained by the CFD simulation, but in faster times. This means relying on a first-guess instrument, capable to address an initial design geometry. The further use of the Look-Up Tables (LUTs) increases the time required to obtain a solution, but links the Simulink model to the CFD simulation in order to reduce the amount of modeled quantities in favor of a greater precision of the model

    The use of Biofeedback in Clinical Virtual Reality: The INTREPID Project

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    Generalized anxiety disorder (GAD) is a psychiatric disorder characterized by a constant and unspecific anxiety that interferes with daily-life activities. Its high prevalence in general population and the severe limitations it causes, point out the necessity to find new efficient strategies to treat it. Together with the cognitive-behavioral treatments, relaxation represents a useful approach for the treatment of GAD, but it has the limitation that it is hard to be learned. The INTREPID project is aimed to implement a new instrument to treat anxiety-related disorders and to test its clinical efficacy in reducing anxiety-related symptoms. The innovation of this approach is the combination of virtual reality and biofeedback, so that the first one is directly modified by the output of the second one. In this way, the patient is made aware of his or her reactions through the modification of some features of the VR environment in real time. Using mental exercises the patient learns to control these physiological parameters and using the feedback provided by the virtual environment is able to gauge his or her success. The supplemental use of portable devices, such as PDA or smart-phones, allows the patient to perform at home, individually and autonomously, the same exercises experienced in therapist's office. The goal is to anchor the learned protocol in a real life context, so enhancing the patients' ability to deal with their symptoms. The expected result is a better and faster learning of relaxation techniques, and thus an increased effectiveness of the treatment if compared with traditional clinical protocols
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