508 research outputs found

    High Multiplicity Searches at the LHC Using Jet Masses

    Full text link
    This article introduces a new class of searches for physics beyond the Standard Model that improves the sensitivity to signals with high jet multiplicity. The proposed searches gain access to high multiplicity signals by reclustering events into large-radius, or "fat," jets and by requiring that each event has multiple massive jets. This technique is applied to supersymmetric scenarios in which gluinos are pair-produced and then subsequently decay to final states with either moderate quantities of missing energy or final states without missing energy. In each of these scenarios, the use of jet mass improves the estimated reach in gluino mass by 20 % to 50 % over current LHC searches.Comment: 9 pages, 6 figures; v3 corrects a few small typo

    Apuntes para un curso de Historia de los Tratados [Manuscrito]: arreglados al programa oficial de la asignatura

    Get PDF
    En cub.: Universidad Central, Historia de los Tratados, Apuntes para el estudio de dicha asignatura, arreglados á las esplicaciones del señor profesor.Pie de imp. de la cub.: Sanchez-Covisa.Antep

    A Distributed System for Robot Manipulator Control

    Get PDF
    This is the final report representing three years of work under the current grant. This work was directed to the development of a distributed computer architecture to function as a force and motion server to a robot system. In the course of this work we developed a compliant contact sensor to provide for transitions between position and force control; we have developed an end-effector capable of securing a stable grasp on an object and a theory of grasping; we have built a controller which minimizes control delays, and are currently achieving delays of the order of five milliseconds, with sample rates of 200 hertz; we have developed parallel kinematics algorithms for the controller; we have developed a consistent approach to the definition of motion both in joint coordinates and in Cartesian coordinates; we have developed a symbolic simplification software package to generate the dynamics equations of a manipulator such that the calculations may be split between background and foreground

    Effects of the herbicide Roundup on freshwater microbial communities: a mesocosm study

    Get PDF
    The impact of the widely used herbicide glyphosate has been mainly studied in terrestrial weed control, laboratory bioassays, and field studies focusing on invertebrates, amphibians, and fishes. Despite the importance of phytoplankton and periphyton communities at the base of the aquatic food webs, fewer studies have investigated the effects of glyphosate on freshwater microbial assemblages. We assessed the effect of the commercial formulation Roundup using artificial earthen mesocosms. The herbicide was added at three doses: a control (without Roundup) and two treatments of 6 and 12 mg/L of the active ingredient (glyphosate). Estimates of the dissipation rate (k) were similar in the two treatments (half-lives of 5.77 and 7.37 d, respectively). The only two physicochemical parameters showing statistically significant differences between treatments and controls were the downward vertical spectral attenuation coefficient kd(λ), where λ is wavelength, and total phosphorus concentration (TP). At the end of the experiment, the treated mesocosms showed a significant increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton decreased in abundance in treated mesocosms. In contrast, the abundance of picocyanobacteria increased by a factor of about 40. Primary production also increased in treated mesocosms (roughly by a factor of two). Similar patterns were observed in the periphytic assemblages, which showed an increased proportion of dead : live individuals and increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in the microbial assemblages were captured by the analysis of the pigment composition of the phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical properties of the water. The observed changes in the structure of the microbial assemblages are more consistent with a direct toxicological effect of glyphosate rather than an indirect effect mediated by phosphorus enrichment.Fil: Pérez, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Torremorell, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Mugni, Hernan Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología ; ArgentinaFil: Rodriguez, Patricia Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vera, Maria Solange. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Do Nascimento, Mauro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Allende, Luz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bustingorry, Jose Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Escaray, Francisco José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Ferraro, Marcela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Izaguirre, Irina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Pizarro, Haydee Norma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Bonetto, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología ; ArgentinaFil: Morris, Donald P.. Lehigh University; Estados UnidosFil: Zagarese, Horacio Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentin

    Emociones y preferencias visuales de consumidores hacia hojuelas de papas (Solanum tuberosum) nativas y clásicas: Estudio comparativo utilizando neurogastronomía y neuromarketing

    Get PDF
    El uso de herramientas tecnológicas, en adición a las técnicas tradicionales, para conocer las emociones y preferencia de los consumidores a productos alimenticios es muy importante para que los desarrolladores de productos tengan mejor información para la toma de decisiones. El objetivo del presente estudio fue utilizar herramientas de la neurogastronomía y neuromarketing para estudiar las emociones y preferencias visuales de los consumidores hacia hojuelas de papas (Solanum tuberosum) nativas y clásicas. Se utilizaron dos tipos de hojuelas frita, papa clásica y papa nativa, con un costo de S/ 6,60 (1.79 USD) y S/ 7,00 (1.90 USD), respectivamente. En una primera etapa se utilizó la tecnología de Seguimiento Ocular y el Análisis de Emoción utilizando una aplicación para teléfono móvil. En una segunda etapa, cada participante respondió una encuesta cognitiva, mediante el uso de formulario Google. Se utilizaron 100 consumidores con edades entre 14 y 63 años. La encuesta mostró que un 45% de los consumidores mostraron su intención de comprar el producto nativo más que el producto clásico. Los resultados de neuromarketing mostraron principalmente una mayor proporción de neutralidad, y un poco menor, en emociones negativas de “escepticismo”, “tristeza” y “disgusto”, especialmente sobre el factor nutricional y el precio. Estos resultados, más que contradictorios son complementarios, ya que las herramientas tecnológicas nos permiten conocer más detalles de las preferencias y elecciones. Los consumidores pretenden consumir más productos nativos, siempre que sean más nutritivos, más sustentables, más baratos y beneficien al productor local

    Robust and efficient configurational molecular sampling via Langevin dynamics

    Get PDF
    A wide variety of numerical methods are evaluated and compared for solving the stochastic differential equations encountered in molecular dynamics. The methods are based on the application of deterministic impulses, drifts, and Brownian motions in some combination. The Baker-Campbell-Hausdorff expansion is used to study sampling accuracy following recent work by the authors, which allows determination of the stepsize-dependent bias in configurational averaging. For harmonic oscillators, configurational averaging is exact for certain schemes, which may result in improved performance in the modelling of biomolecules where bond stretches play a prominent role. For general systems, an optimal method can be identified that has very low bias compared to alternatives. In simulations of the alanine dipeptide reported here (both solvated and unsolvated), higher accuracy is obtained without loss of computational efficiency, while allowing large timestep, and with no impairment of the conformational exploration rate (the effective diffusion rate observed in simulation). The optimal scheme is a uniformly better performing algorithm for molecular sampling, with overall efficiency improvements of 25% or more in practical timestep size achievable in vacuum, and with reductions in the error of configurational averages of a factor of ten or more attainable in solvated simulations at large timestep.Comment: The article has been submitted to the Journal of Chemical Physic

    An approach to assess flooding and erosion risk for open beaches in a changing climate

    Get PDF
    This paper examines the vulnerability to flooding and erosion of four open beach study sites in Europe. A framework for the quantitative estimation of present and future coastal flood and erosion risks is established using methods, data and tools from across a range of disciplines, including topographic and bathymetric data, climate data from observation, hindcast and model projections, statistical modelling of current and future climates and integrated risk analysis tools. Uncertainties in the estimation of future coastal system dynamics are considered, as are the consequences for the inland systems. Different implementations of the framework are applied to the study sites which have different wave, tidal and surge climate conditions. These sites are: Santander, Spain—the Atlantic Ocean; Bellocchio, Italy—the Adriatic Sea; Varna, Bulgaria—the Black Sea; and the Teign Estuary, UK—the northern Atlantic Ocean. The complexity of each system is first simplified by sub-division into coastal "impact units" defined by homogeneity in the local key forcing parameters: wave, wind, tide, river discharge, run-off, etc. This reduces the simulation to that of a number of simpler linear problems which are treated by applying the first two components of the Source–Pathway–Receptor–Consequence (S–P–R–C) approach. The case studies reveal the flexibility of this approach, which is found useful for the rapid assessment of the risks of flooding and erosion for a range of scenarios and the likely effectiveness of flood defences

    Where the Sidewalk Ends: Jets and Missing Energy Search Strategies for the 7 TeV LHC

    Get PDF
    This work explores the potential reach of the 7 TeV LHC to new colored states in the context of simplified models and addresses the issue of which search regions are necessary to cover an extensive set of event topologies and kinematic regimes. This article demonstrates that if searches are designed to focus on specific regions of phase space, then new physics may be missed if it lies in unexpected corners. Simple multiregion search strategies can be designed to cover all of kinematic possibilities. A set of benchmark models are created that cover the qualitatively different signatures and a benchmark multiregion search strategy is presented that covers these models.Comment: 30 pages, 8 Figures, 3 Tables. Version accepted at JHEP. Minor changes. Added figur
    corecore