489 research outputs found

    Associated production of top quarks and charged Higgs bosons at next-to-leading order

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    Accurate predictions for both signal and background events at the LHC are of paramount importance in order to confirm even the smallest deviations from Standard Model predicitions. Next-to-leading order Monte Carlo event generators are an essential tool to reach that goal. Concerning the charged Higgs boson, NLO calculations of the production cross section already exist. Reiterating the calculation using a subtraction formalism enables us to implement the cross section into Monte Carlo generators, which can then be used by experiments

    FREE-OSCILLATION VARIABLE-DEFLECTION DYNAMIC RIG

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    Sandia Corporation Dynannic Rig No. 11 was designed to facilitate the dynamic stability testing of store models in the Sandia Corporation 12" x 12" blow down wind-tunnel facility. The rig was designed to provide a convenient and rapid method for shifting model center of rotation with respect to the rig oscillating head, and to make it possible to easily adjust the deflection mechanism to deflect and release the model at any angle desired within limits of the model and mechanism. Also, the rig has a locking unit which allows a model to be suddenly released from a zero angle orientation, and permits an oscillating model to be brought to rest. (auth

    Associated production of charged Higgs bosons and top quarks with POWHEG

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    The associated production of charged Higgs bosons and top quarks at hadron colliders is an important discovery channel to establish the existence of a non-minimal Higgs sector. Here, we present details of a next-to-leading order (NLO) calculation of this process using the Catani-Seymour dipole formalism and describe its implementation in POWHEG, which allows to match NLO calculations to parton showers. Numerical predictions are presented using the PYTHIA parton shower and are compared to those obtained previously at fixed order, to a leading order calculation matched to the PYTHIA parton shower, and to a different NLO calculation matched to the HERWIG parton shower with MC@NLO. We also present numerical predictions and theoretical uncertainties for various Two Higgs Doublet Models at the Tevatron and LHC.Comment: 36 page

    The portal of Neviaser: a valid option for antegrade nailing of humerus fractures

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    Introduction: The objective of this retrospective non-randomized study was to evaluate the portal of Neviaser (PN) as an alternative approach in antegrade humeral nailing. Methods: The surgical approach for the straight antegrade intramedullary nail (SAIN) was either the anterolateral delta-split (group 2, n = 79) or the portal of Neviaser (group 3, n = 27). Length of surgery and time of radiation were extracted from charts. Patients stabilized using the PN were followed for a clinical and radiological exam. At follow-up we evaluated the DASH (Disability of the Arm, Shoulder and Hand) and CMS (Constant-Murley Score). Results: Between 10.2015 and 12.2018 191 proximal and diaphyseal humeral fractures were operated using either an angular stable extramedullary device (group 1, PHILOS®, n = 85) or a straight humeral nail (MultiLoc®, n = 106). Time of radiation and intervention followed a normal distribution. The mean length of surgery was 172.9 min (SD 91.5) in group 1, 121.5 min (SD 54.1) in group 2 and 96.4 min (SD 33.7) in group 3 (p < 0.01). Time of radiation was significantly different with 1.1 min (SD 0.6: group 1), 3.1 min (SD 1.6: group 2) and 2.9 min (SD 1.7: group 3) (p < 0.01). After a mean interval of 21.5 months (range 6–43 months) 14 / 27 patients of group 3 were available for a clinical and radiological follow-up. The mean DASH in group 3 was 25, the CMS reached 70. The age and sex weighted CMS mean value was 96%. Forward flexion was 131°, abduction 125°. The ratio of strength affected versus non-affected side was 4.4: 6.2 kg. Conclusions: The portal of Neviaser is a feasible and safe approach and is an alternative to the anterolateral delta-split. Length of surgery and time of radiation were significantly shorter. Level of evidence: IV

    Gestión pedagógica y el rendimiento escolar en el área de matemática

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    The research aimed to demonstrate the incidence of pedagogical management in the school performance of the area of ​​mathematics in secondary school students of the educational institution Santo Domingo de Jicamarca-Lima 2018. The research is quantitative, with a type and descriptive correlational design. The data collection instrument that was used is the survey, validated by expert judgment and establishing the reliability of 0.91 on the Cronbach Alpha scale. We worked with a sample consisting of: 72 fourth-year students and 60 fifth-year students. The results show that there is a positive relationship of 0.862 between pedagogical management and school performance in the area of ​​mathematics in secondary school students; Therefore, it is concluded that it is important to make profound changes in the conception of educational environments and in the curricular field, including contents and pedagogical managements.La investigación planteó como objetivo demostrar la incidencia de la gestión pedagógica en el rendimiento escolar del área de matemática en estudiantes de educación secundaria de la institución educativa Santo Domingo de Jicamarca-Lima 2018. La investigación es cuantitativa, con un tipo y diseño descriptivo correlacional. El instrumento de recolección de datos que se utilizó es la encuesta, validado mediante juicio de expertos y estableciéndose la confiabilidad de 0.91 en la escala del Alfa de Cronbach. Se trabajó con una muestra conformada por: 72 estudiantes de cuarto año y 60 estudiantes de quinto año. Los resultados muestran que existe una relación positiva de 0.862 entre la gestión pedagógica y el rendimiento escolar del área de matemática en los estudiantes de educación secundaria; por lo que se concluye que es importante realizar profundos cambios en la concepción de los ambientes educativos y en el campo curricular, incluyendo contenidos y gestiones pedagógicas

    Gestión pedagógica y el rendimiento escolar en el área de matemática

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    The research aimed to demonstrate the incidence of pedagogical management in the school performance of the area of ​​mathematics in secondary school students of the educational institution Santo Domingo de Jicamarca-Lima 2018. The research is quantitative, with a type and descriptive correlational design. The data collection instrument that was used is the survey, validated by expert judgment and establishing the reliability of 0.91 on the Cronbach Alpha scale. We worked with a sample consisting of: 72 fourth-year students and 60 fifth-year students. The results show that there is a positive relationship of 0.862 between pedagogical management and school performance in the area of ​​mathematics in secondary school students; Therefore, it is concluded that it is important to make profound changes in the conception of educational environments and in the curricular field, including contents and pedagogical managements.La investigación planteó como objetivo demostrar la incidencia de la gestión pedagógica en el rendimiento escolar del área de matemática en estudiantes de educación secundaria de la institución educativa Santo Domingo de Jicamarca-Lima 2018. La investigación es cuantitativa, con un tipo y diseño descriptivo correlacional. El instrumento de recolección de datos que se utilizó es la encuesta, validado mediante juicio de expertos y estableciéndose la confiabilidad de 0.91 en la escala del Alfa de Cronbach. Se trabajó con una muestra conformada por: 72 estudiantes de cuarto año y 60 estudiantes de quinto año. Los resultados muestran que existe una relación positiva de 0.862 entre la gestión pedagógica y el rendimiento escolar del área de matemática en los estudiantes de educación secundaria; por lo que se concluye que es importante realizar profundos cambios en la concepción de los ambientes educativos y en el campo curricular, incluyendo contenidos y gestiones pedagógicas

    L’invasion mondiale de Drosophila suzukii : être une espèce « cousine » d’un organisme-modèle aide-t-il réellement à établir un contrôle biologique ? Espoirs, désillusions et nouvelles perspectives

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    L’invasion récente et rapide de Drosophila suzukii en Europe et en Amérique du Nord a suscité de nombreuses études sur le terrain comme en laboratoire. Cette drosophile est en effet à la fois un ravageur important, du fait de son développement dans des fruits à maturité, et une « cousine » de l’espèce modèle Drosophila melanogaster dont la biologie et la génétique sont bien connues. Cet article s’appuie sur les données publiées par différentes équipes et sur des résultats préliminaires pour discuter de l’avancée des recherches et notamment des questions suivantes: en quoi nos connaissances sur D. melanogaster peuvent-elles ou non aider à comprendre et gérer l’invasion de D. suzukii ? Les résultats obtenus en condition de laboratoire avec cette espèce sont-ils représentatifs de sa biologie ? Comment mesurer l’impact écologique d’une espèce invasive si la niche qu’elle vient occuper est peu décrite localement en termes d’espèces présentes et de réseaux trophiques ? Cet article discute aussi des pistes et contraintes en termes de lutte biologique et de biocontrôleThe recent and rapid invasion of Europe and North-America by Drosophila suzukii has generated numerous laboratory and field studies since this fly species is an agricultural pest that causes economical losses by laying eggs and developing in ripening fruits, but also because of its relatedness with the model species Drosophila melanogaster whose biology and genetics are well described. This commentary is based on recent data published by different research groups as well as some of our own preliminary results. It discusses the state of research on D. suzukii and addresses the main following questions: can the wide knowledge on D. melanogaster help us to understand and manage the D. suzukii invasion and how? Are lab results on D. suzukii really informative on its biology? How can the ecological impact of an invasive species be evaluated if the ecological niche is poorly described in terms of biodiversity and trophic network? We also outline constraints for the biological control of this pest species and suggest new possible approaches for its long-term managemen

    NLO QCD corrections to tW' and tZ' production in forward-backward asymmetry models

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    We consider Z' and W' models recently proposed to explain the top forward-backward asymmetry at the Tevatron. We present the next-to-leading order QCD corrections to associated production of such vector bosons together with top quarks at the Large Hadron Collider, for centre-of-mass energies of 7 and 8 TeV. The corrections are significant, modifying the total production cross-section by 30-50%. We consider the effects of the corrections on the top and vector-boson kinematics. The results are directly applicable to current experimental searches, for both the ATLAS and CMS collaborations.Comment: 62 pages, 13 figures, 36 tables. v3 Updated to correspond to Journal version and incorporate supplementary materia

    Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV

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    Motivated by hints for a light Standard Model-like Higgs boson and a shift in experimental attention towards electroweak supersymmetry particle production at the CERN LHC, we update in this paper our precision predictions at next-to-leading order of perturbative QCD matched to resummation at the next-to-leading logarithmic accuracy for direct gaugino pair production in proton-proton collisions with a center-of-mass energy of 8 TeV. Tables of total cross sections are presented together with the corresponding scale and parton density uncertainties for benchmark points adopted recently by the experimental collaborations, and figures are presented for up-to-date model lines attached to them. Since the experimental analyses are currently obtained with parton showers matched to multi-parton matrix elements, we also analyze the precision of this procedure by comparing invariant-mass and transverse-momentum distributions obtained in this way to those obtained with threshold and transverse-momentum resummation.Comment: 28 pages, 7 figures, 9 tables; version to appear in JHE
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