645 research outputs found

    Implementación de una WSN basado en 6LoWPAN para mejorar el sistema de seguridad vehicular preventivo.

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    Se implementó una WSN basado en 6LoWPAN para mejorar el sistema de seguridad vehicular preventiva, originalmente se hizo un breve estudio sobre las redes de sensores inalámbricas, para determinar los mejores parámetros para la red, posteriormente se simularon estos parámetros, en el software de simulación de WSN Cooja, posteriormente se procedió a la configuración y ensamblaje de cada uno de los nodos que conformaban la red, en esta etapa se corrigieron muchas fallas, como la comunicación entre los nodos, retardos en el sistema, calibración de los sensores. Luego de la optimización del sistema, se procedió a su implementación sobre un vehículo que presente las características de un vehículo de clase media baja, un Chevrolet Steem, del año 1999, el cual carecía de sistemas de seguridad preventivo que viene de fábrica. Para el montaje en el vehículo se tomaron las señales del switch para determinar el encendido del vehículo y se colocó el limitador de velocidad en serie con la conexión a positivo de la bobina del vehículo, se colocaron los sensores de contacto, giro, velocidad y humedad, se conectaron a sus respectivos nodos sensores y se los alimentó con una batería de 9 voltios. Posterior a la implementación se puso a prueba cada uno de los sensores en condiciones adversas y se calibraron minuciosamente. El sistema se ha evaluado en base de ciertos parámetros de seguridad vehicular en la cual se ha establecido que el vehículo al inicio de trabajo tenía una seguridad vehicular del 33.3%, mientras que una vez implementado el sistema obtuvo una seguridad del 90%, adicionando al sistema inicial un 57.3% de seguridad. Se puede determinar que 6LoWPAN es un estándar idóneo para el uso de estas aplicaciones brindando un mejor desempeño a sistemas de este tipo. Se recomienda atender con premura las alertas del sistema antes que se active el sistema de bloqueo.It was implemented a WSN base on 6LoWPAN to improve preventive vehicle safety system, originally it was a short study on wireless sensor networks, to determine the best parameters for the network, then these parameters in simulation of WSN Cooja software were simulated, subsequently was setup and Assembly of each of the nodes that were part of the network at this stage is corrected many failures, as communication between the nodes, delays in the system, calibration of the sensors. After the optimization of the system was its implementation on a vahicle which present the characteristics of a vehicle’s lower middle class, a Chevrolet Steem, of 1999, which lacked preventive security that comes from tha factory. Vehicle-mountable switch signals were taken to determine the vehicle’s ignition in series speed limiter was placed with connection to positive of vehicle coil, contact, spin, speed, and humidity sensors were placed, it was connected to its respective sensor nodes and he fed them with a 9-volt battery. Post-deployment it was putt o test each of the sensors in adverse conditions and they were carefully calibrated. The system has been evaluated on the basis of certain parameters of vehicle safety has been established in which the vehicle to the star of work had a vehicle safety of the 33.3%, while once implemented the system won a safety of 90%, adding to the initial system, a 57.3% security. It can be determine 6LoWPAN is a standard suitable for the use of these applications to provide better performance to systems of this type. Please respond quickly alerts the system before that the locking system is activated

    Responses of anaerobic microorganisms to different culture conditions and corresponding effects on biogas production and solid digestate quality

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    Microbial communities of anaerobic digestion have been intensively investigated in the past decades. Majority of these studies focused on correlating microbial diversity with biogas production. The relationship between microbial communities and compositional changes of the solid digestate (AD fiber) has not been comprehensively studied to date. Therefore, the objective of this study was to understand the responses of microbial communities to different operational conditions of anaerobic co-digestion and their influences on biogas production and solid digestate quality. Two temperatures and three manure-to-food waste ratios were investigated by a completely randomized design. Molecular analyses demonstrate that both temperature and manure-to-food waste ratio greatly influenced the bacterial communities, while archaeal communities were mainly influenced by temperature. The digestion performance showed that biogas productivity increased with the increase of supplemental food wastes, and there were no significant differences on carbohydrate contents among different digestions. The statistical analyses conclude that microbes changed their community configuration under different conditions to enhance digestion performance for biogas and homogenized solid digestate production.U.S. Department of State West Hemisphere Affairs/[S-LMAQM-11-GR-075]//Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Estación Experimental Agrícola Fabio Baudrit Moreno (EEAFBM

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

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    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

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    Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

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    A fiducial cross section for W gamma production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137 fb(-1) of data collected using the CMS detector at the LHC. The W -> e nu and mu nu decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.Peer reviewe

    Search for top squark production in fully hadronic final states in proton-proton collisions at root s=13 TeV

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    A search for production of the supersymmetric partners of the top quark, top squarks, is presented. The search is based on proton-proton collision events containing multiple jets, no leptons, and large transverse momentum imbalance. The data were collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 137 fb(-1). The targeted signal production scenarios are direct and gluino-mediated top squark production, including scenarios in which the top squark and neutralino masses are nearly degenerate. The search utilizes novel algorithms based on deep neural networks that identify hadronically decaying top quarks and W bosons, which are expected in many of the targeted signal models. No statistically significant excess of events is observed relative to the expectation from the standard model, and limits on the top squark production cross section are obtained in the context of simplified supersymmetric models for various production and decay modes. Exclusion limits as high as 1310 GeVare established at the 95% confidence level on the mass of the top squark for direct top squark production models, and as high as 2260 GeV on the mass of the gluino for gluino-mediated top squark production models. These results represent a significant improvement over the results of previous searches for supersymmetry by CMS in the same final state.Peer reviewe
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