1,523 research outputs found

    Classifying Galileon pp-form theories

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    We provide a complete classification of all abelian gauge invariant pp-form theories with equations of motion depending only on the second derivative of the field---the pp-form analogues of the Galileon scalar field theory. We construct explicitly the nontrivial actions that exist for spacetime dimension D≀11D\leq11, but our methods are general enough and can be extended to arbitrary DD. We uncover in particular a new 44-form Galileon cubic theory in D≄8D\geq8 dimensions. As a by-product we give a simple proof of the fact that the equations of motion depend on the pp-form gauge fields only through their field strengths, and show this explicitly for the recently discovered 33-form Galileon quartic theory.Comment: 17 pages; v2: references adde

    EFFECTS OF ONE-HOUR ROAD RUNNING AND SHOE ON TIBIAL ACCELERATIONS IN RECREATIONAL RUNNERS

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    The purpose of this study was twofold. Firstly, we evaluated the effect of one-hour running on tibial acceleration parameters. Secondly, we determined whether the shoe fatigue after one-hour running would influence these tibial acceleration parameters. Ten runners ran at a constant preferred speed with a standard running shoe. They also ran one bout of 5 min with another identical but fresh running shoe before and after the one-hour run. Tibial acceleration amplitudes and wavelet analyses demonstrated a significant reduction of the tibial impact parameters after one-hour running, but no significant shoe effect. These reductions could be attributable to the slight increase in stride frequency from the beginning to the end of the one-hour running. Noteworthy, the tibial acceleration reduction was observable along the anteroposterior axis, not along the vertical axis. Considering the tibial acceleration as a potential risk factor for developing running-related injuries, these parameters did not change in a harmful way after one-hour of running at the preferred running speed. The shoe modification during the one-hour run did not seem to influence running biomechanics

    Prediction of responsibility for drivers and riders involved in injury road crashes

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    Responsibility analysis allows the evaluation of crash risk factors from crash data only, but requires a reliable responsibility assessment. The aim of the present study is to predict expert responsibility attribution (considered as a gold-standard) from explanatory variables available in crash data routinely recorded by the police, according to a data-driven process with explicit rules. Method: Driver responsibility was assessed by experts using all information contained in police reports for a sample of about 5000 injury crashes that occurred in France in 2011. Three statistical methods were used to predict expert responsibility attribution: logistic regression with L1 penalty, random forests, and boosting. Potential predictors of expert attribution referred to inappropriate driver actions and to external conditions at the time of the crash. Logistic regression was chosen to construct a score to assess responsibility for drivers and riders in crashes involving one or more motor vehicles, or involving a cyclist or pedestrian. Results: Cross-validation showed that our tool can predict expert responsibility assessments on new data sets. In addition, responsibility analyses performed using either the expert responsibility or our predicted responsibility return similar odds ratios. Our scoring process can then be used to reliably assess responsibility based on national police report databases, provided that they include the information needed to construct the score

    “Un tout non hĂ©gĂ©monique”

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    CĂ©dric Chauvin & Arnaud Despax Commençons, en remontant votre temps biographique, par parler de science-fiction. Dans une communication non publiĂ©e, vous montrez comment les “histoires du futur” du XXe siĂšcle sont imprĂ©gnĂ©es des philosophies de l’Histoire des XVIIIe et XIXe siĂšcles, qui les auraient rendues possibles : plus prĂ©cisĂ©ment, la science-fiction se dĂ©finirait, en rĂ©ponse Ă  la double fermeture du passĂ© par les philosophies de l’Histoire et de la Terre par son exploration, comme proje..

    The macrofilaricidal efficacy of repeated doses of ivermectin for the treatment of river blindness

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    Background: Mass drug administration (MDA) with ivermectin is the cornerstone of efforts to eliminate human onchocerciasis by 2020 or 2025. The feasibility of elimination crucially depends on the effects of multiple ivermectin doses on Onchocerca volvulus. A single ivermectin (standard) dose clears the skin-dwelling microfilarial progeny of adult worms (macrofilariae) and temporarily impedes the release of such progeny by female macrofilariae, but a macrofilaricidal effect has been deemed minimal. Multiple doses of ivermectin may cumulatively and permanently reduce the fertility and shorten the lifespan of adult females. However, rigorous quantification of these effects necessitates interrogating longitudinal data on macrofilariae with suitably powerful analytical techniques. Methods: Using a novel mathematical modeling approach, we analyzed, at an individual participant level, longitudinal data on viability and fertility of female worms from the single most comprehensive multiple-dose clinical trial of ivermectin, comparing 3-monthly with annual treatments administered for 3 years in Cameroon

    REPAS : Responsabilité estimée par apprentissage statistique - Rapport final

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    Responsibility analysis makes it possible to estimate crash risk factors from crash data only. One necessary condition to achieve this objective is to dispose of a reliable responsibility assessment. The aim of the present study was to predict expert responsibility attribution (considered as gold-standard) from crash data routinely recorded by the police. The final objective was to estimate driver responsibility in crashes according to a data-driven process with explicit rules. Driver responsibility was attributed by experts in the light of all information contained in the police reports, including accident diagrams and photographs for a sample of 5,000 injury crashes that occurred in France in 2011. This expert responsibility was transformed into a binary variable (1 if totally or rather responsible, 0 if totally or rather not responsible). Explanatory variables were found in the database which yearly includes computerized information from police reports for all of France. As potential predictors of expert attribution, we considered variables referring to inappropriate actions, such as driving the wrong way, speeding, failure to give way, making a half-turn or overtaking, etc. We also included as potential predictors some variables referring to external conditions at the time of the accident such as weather or road condition. As the set of explanatory variables could vary according to the type of accident, the three most frequent accident configurations were considered separately: (1) accident involving only motor vehicles, 2 or more; (2) accident involving a motor vehicle and a pedestrian or a cyclist; (3) accident involving only 1 motor vehicle. Three different statistical methods for each accident configuration were implemented to predict expert responsibility attribution: logistic regression with L1 penalty, random forests, and boosting. After cross-validation for logistic regression and boosting and out-of-bag estimation for random forests, the three statistical methods showed similar performance in terms of accuracy, sensitivity, specificity and reliability for accident configurations 1 and 2. We therefore chose logistic regression, which is suitable for predictions based on a risk/prediction score. The prediction score was also validated by estimating and comparing odds ratios (ORs) obtained for certain risk factors, using the predictions and expert responsibility assessments. The ORs for predictions and expert attributions were very close, except in case of high blood alcohol content, where they were lower using predictions. Based on expert decisions for a fairly large number of police accident reports, we constructed a score to assess responsibility for drivers and riders in accidents involving one or more motor vehicles, or involving a cyclist or pedestrian. The score could directly be applicable to French police data. The methodology could be adapted for other police data, and R scripts are available from the authors upon request. Further work is needed to validate this responsibility assessment, notably using similar police data such as those in the European CARE database.L'analyse de responsabilitĂ© permet d'estimer les facteurs de risque d'accident Ă  partir des donnĂ©es d'accident uniquement. Une condition nĂ©cessaire pour atteindre cet objectif est de disposer d'une Ă©valuation fiable de la responsabilitĂ©. L'objectif de la prĂ©sente Ă©tude Ă©tait de prĂ©dire l'attribution de la responsabilitĂ© des experts (considĂ©rĂ©e comme l'Ă©talon-or) Ă  partir des donnĂ©es d'accidents rĂ©guliĂšrement enregistrĂ©es par la police. L'objectif final Ă©tait d'estimer la responsabilitĂ© du conducteur en cas d'accident selon un processus guidĂ© par des donnĂ©es et des rĂšgles explicites. La responsabilitĂ© du conducteur a Ă©tĂ© attribuĂ©e par les experts Ă  la lumiĂšre de l'ensemble des informations contenues dans les rapports de police, y compris les schĂ©mas d'accidents et les photographies pour un Ă©chantillon de 5 000 accidents corporels survenus en France en 2011. Cette responsabilitĂ© d'expert a Ă©tĂ© transformĂ©e en variable binaire (1 si totalement ou plutĂŽt responsable, 0 si totalement ou plutĂŽt non responsable). Des variables explicatives ont Ă©tĂ© trouvĂ©es dans la base de donnĂ©es qui inclut chaque annĂ©e des informations informatisĂ©es issues des rapports de police pour l'ensemble de la France. En tant que prĂ©dicteurs potentiels de l'attribution par des experts, nous avons pris en compte des variables se rĂ©fĂ©rant Ă  des actions inappropriĂ©es, telles que conduire dans le mauvais sens, excĂšs de vitesse, ne pas cĂ©der le passage, faire un demi-tour ou un dĂ©passement, etc. Nous avons Ă©galement inclus comme prĂ©dicteurs potentiels certaines variables se rapportant aux conditions externes au moment de l'accident, comme les conditions mĂ©tĂ©orologiques ou l'Ă©tat de la route. L'ensemble des variables explicatives pouvant varier selon le type d'accident, les trois configurations d'accident les plus frĂ©quentes ont Ă©tĂ© considĂ©rĂ©es sĂ©parĂ©ment : (1) accident impliquant uniquement des vĂ©hicules Ă  moteur, 2 ou plus ; (2) accident impliquant un vĂ©hicule Ă  moteur et un piĂ©ton ou un cycliste ; (3) accident impliquant un seul vĂ©hicule Ă  moteur. Trois mĂ©thodes statistiques diffĂ©rentes ont Ă©tĂ© mises en oeuvre pour chaque configuration d'accident afin de prĂ©dire l'attribution de la responsabilitĂ© des experts : rĂ©gression logistique avec pĂ©nalitĂ© L1, forĂȘts alĂ©atoires et boosting. AprĂšs validation croisĂ©e pour la rĂ©gression logistique et le boosting, et l'estimation "out-of-bag" pour les forĂȘts alĂ©atoires, les trois mĂ©thodes statistiques ont montrĂ© des performances similaires en termes de prĂ©cision, de sensibilitĂ©, de spĂ©cificitĂ© et de fiabilitĂ© pour les configurations 1 et 2 des accidents. Nous avons donc choisi la rĂ©gression logistique, qui convient aux prĂ©dictions basĂ©es sur un score risque/prĂ©vision. Le score de prĂ©diction a Ă©galement Ă©tĂ© validĂ© en estimant et en comparant les odds-ratios (OR) obtenus pour certains facteurs de risque, en utilisant les prĂ©dictions et les Ă©valuations de responsabilitĂ© des experts. Les ORs pour les prĂ©dictions et les attributions d'experts Ă©taient trĂšs proches, sauf en cas d'alcoolĂ©mie Ă©levĂ©e, oĂč ils Ă©taient plus faibles en utilisant les prĂ©dictions. En nous fondant sur les dĂ©cisions d'experts d'un assez grand nombre de rapports d'accident de la police, nous avons Ă©tabli un score pour Ă©valuer la responsabilitĂ© des conducteurs et des conducteurs dans les accidents impliquant un ou plusieurs vĂ©hicules automobiles, un cycliste ou un piĂ©ton. Le score pourrait ĂȘtre directement applicable aux donnĂ©es des forces de l'ordre françaises. La mĂ©thodologie pourrait ĂȘtre adaptĂ©e Ă  d'autres donnĂ©es policiĂšres, et des scripts R sont disponibles sur demande auprĂšs des auteurs. Des travaux supplĂ©mentaires sont nĂ©cessaires pour valider cette Ă©valuation de la responsabilitĂ©, notamment en utilisant des donnĂ©es policiĂšres similaires telles que celles de la base de donnĂ©es europĂ©enne CARE

    Hybrid approach for energy aware management of multi-cloud architecture integrating user machines

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    International audienceThe arrival and development of remotely accessible services via the cloud has transfigured computer technology. However, its impact on personal computing remains limited to cloud-based applications. Meanwhile, acceptance and usage of telephony and smartphones have exploded. Their sparse administration needs and general user friendliness allows all people, regardless of technology literacy, to access, install and use a large variety of applications.We propose in this paper a model and a platform to offer personal computing a simple and transparent usage similar to modern telephony. In this model, user machines are integrated within the classical cloud model, consequently expanding available resources and management targets. In particular, we defined and implemented a modular architecture including resource managers at different levels that take into account energy and QoS concerns. We also propose simulation tools to design and size the underlying infrastructure to cope with the explosion of usage. Functionalities of the resulting platform are validated and demonstrated through various utilization scenarios. The internal scheduler managing resource usage is experimentally evaluated and compared with classical method-ologies, showing a significant reduction of energy consumption with almost no QoS degradation

    EnquĂȘte sur le rapport Ă  la rĂšgle chez les automobilistes français.

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    La sĂ©curitĂ© routiĂšre est un problĂšme majeur pour les politiques publiques dans le monde entier. En 2016, la France a enregistrĂ© 3 477 tuĂ©s dans des accidents de la route et est confrontĂ©e Ă  des difficultĂ©s pour rĂ©duire ce nombre depuis quelques annĂ©es (ONISR, 2017a). MalgrĂ© la mise en place de lois plus strictes et un renforcement des contrĂŽles, il arrive frĂ©quemment que les conducteurs ne respectent pas le Code de la route. En 2016, sans compter les infractions aux rĂšgles de stationnement, plus de 20 millions d'infractions ont Ă©tĂ© enregistrĂ©es (en augmentation de 14,5 % par rapport Ă  l'annĂ©e 2015) et plus de 13 millions de points ont Ă©tĂ© retirĂ©s (ONISR, 2017b). Afin de comprendre quelles motivations sous-tendent ces violations de la loi, nous avons menĂ© une enquĂȘte en ligne sur un Ă©chantillon reprĂ©sentatif de 1 021 conducteurs français. ConformĂ©ment Ă  nos attentes, nous avons constatĂ© que les femmes et les conducteurs ĂągĂ©s dĂ©claraient une plus grande conformitĂ© Ă  la loi. NĂ©anmoins, les effets de l'Ăąge et du genre sur le respect des rĂšgles restent de faible ampleur dans notre Ă©chantillon. En outre, nous avons identifiĂ© plusieurs processus psychologiques impliquĂ©s dans la relation entre les conducteurs et les rĂšgles de sĂ©curitĂ© telles que le biais d'auto-complaisance ou le faux consensus. La plupart des personnes interrogĂ©es mettent en cause la lĂ©gitimitĂ© de certaines rĂšgles et ont tendance Ă  les considĂ©rer comme conditionnelles. Ce relativisme peut expliquer pour partie la rĂ©alisation d'infractions par les conducteurs. En effet, ils ont tendance Ă  substituer aux rĂšgles de conduite officielles des normes informelles en fonction du contexte de conduite, et le strict respect des rĂšgles de sĂ©curitĂ© est souvent remplacĂ© par une approche conditionnelle. Les politiques publiques doivent tenir compte du scepticisme des conducteurs quant Ă  la lĂ©gitimitĂ© des rĂšgles de sĂ©curitĂ© routiĂšre. Il est notamment recommandĂ© de modifier les stratĂ©gies de communication lors de la mise en oeuvre de nouvelles mesures et un renforcement des contrĂŽles des rĂšgles tout en s'assurant de leur lĂ©gitimitĂ© et leur effectivitĂ©

    Differences and similarities in the effects of ibrutinib and acalabrutinib on platelet functions

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    While efficient at treating B-cell malignancies, Bruton tyrosine kinase (BTK) inhibitors are consistently reported to increase the risk of bleeding. Analyzing platelet aggregation response to collagen in platelet-rich plasma allowed us to identify two groups in the healthy population characterized by low or high sensitivity to ibrutinib in vitro. Inhibition of drug efflux pumps induced a shift from ibrutinib low-sensitive platelets to high-sensitive ones. At a clinically relevant dose, acalabrutinib, a second-generation BTK inhibitor, did not affect maximal collagen-induced platelet aggregation in the ibrutinib low-sensitive group but did inhibit aggregation in a small fraction of the ibrutinib high-sensitive group. Consistently, acalabrutinib delayed aggregation, particularly in the ibrutinib high-sensitive group. In chronic lymphocytic leukemia patients, acalabrutinib inhibited maximal platelet aggregation only in the ibrutinib high-sensitive group. Acalabrutinib inhibited collagen-induced tyrosine-753 phosphorylation of phospholipase CÎł2 in both groups, but, in contrast to ibrutinib, did not affect Src-family kinases. Acalabrutinib affected thrombus growth under flow only in the ibrutinib high-sensitive group and potentiated the effect of cyclooxygenase and P2Y12 receptor blockers in both groups. Since the better profile of acalabrutinib was observed mainly in the ibrutinib low-sensitive group, replacement therapy in patients may not systematically reduce the risk of bleeding
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