A search for pair-produced resonances in four-jet final states at root s=13 TeV with the ATLAS detector

A search for massive coloured resonances which are pair-produced and decay into two jets is presented. The analysis uses 36.7 fb−1 − 1 of √ s = 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the background prediction is observed. Results are interpreted in a SUSY simplified model where the lightest supersymmetric particle is the top squark, ̃ t ~ , which decays promptly into two quarks through R-parity-violating couplings. Top squarks with masses in the range 100 GeV<̃<410 100 GeV < m t ~ < 410 GeV GeV are excluded at 95% confidence level. If the decay is into a b-quark and a light quark, a dedicated selection requiring two b-tags is used to exclude masses in the ranges 100 GeV<̃<470 100 GeV < m t ~ < 470 GeV GeV and 480 GeV<̃<610 480 GeV < m t ~ < 610 GeV GeV . Additional limits are set on the pair-production of massive colour-octet resonances

Crianças e jovens, atores sociais na escola: como os compreender? Children and young people as social actors in school: how to understand them?

Este texto apresenta uma reflexão sobre o processo metodológico que iniciei por ocasião de pesquisas que venho fazendo há 12 anos sobre a socialização das crianças e dos jovens de níveis diversos de escolarização. A preocupação de me liberar do "adultocentrismo", que muitas vezes impede de aceder às categorias específicas da experiência social infantil, levou-me a utilizar instrumentos de pesquisa que escolhi múltiplos e adaptados a atores socais em toda a extensão da palavra. Crianças e jovens não se comportam como adultos acabados, são, porém, tanto quanto estes, desejosos de analisar e de redefinir no seu próprio interesse as coerções situacionais sobre eles exercidas individualmente ou coletivamente. Para entender as tribulações que assim enfrentam como o sentido que eles lhes dão, utilizei, de modo geral, entrevistas inspiradas em métodos etnográficos, mas criei também cenários a partir dos quais crianças podem exprimir perfeitamente conceitos, já bem elaborados, sobre a justiça e a vida pública. O estudo de incidentes-chave ou de "negócios" levando-os a enfrentar atores adultos permitiu-me igualmente apresentar algumas propostas sobre as diversas maneiras que eles têm de viver juntos em diferentes momentos da escolaridade. Enfim a importância dada ao objeto do trabalho escolar, como a redação de textos "longos", permitiu-me abordar a relação aos "saberes" de um ponto de vista que a narração da experiência, somente, oculta de modo geral. Em todas essas pesquisas, esforcei-me igualmente a não opô-las; tentei, de preferência, conciliar pontos de vista qualitativos com tratamentos quantitativos na esperança de ter acesso simultaneamente ao significativo e ao representativo.<br>This article presents a reflexive analysis of the methods of investigation that I have used over twelve years of research on children and youth socialisation at different school levels. The desire to free myself from an "adult-centred" position that prevents researchers to reach the specific categories of children's social experience has led me to develop multiple research tools adapted to these social actors. Children do not behave, it is true, as accomplished adults, but they wish, as them, to analyse and redefine at their advantage the situational constraints that they meet individually or collectively. To understand the trials they are confronted to and the meaning they give to them I have used ethnographic interviews, but I have also conceived scripts from which children can perfectly express well-developed conceptions of justice and politics. The analysis of key incidents or "affairs" that confront children to adults has also allowed me to put forward some propositions concerning their group sociability at different points in their school careers. Finally, the examination of some dimensions of schoolwork such as "long" written texts has led me to analyse a relationship to school "knowledge" that life stories usually neglect. In all these research studies, I have tried to combine qualitative and quantitative approaches rather than opposing them in the hope of both gaining insight and being able to generalise

High-Pressure Densities of 2,2,2-Trifluoroethanol + Ionic Liquid Mixtures Useful for Possible Applications in Absorption Cycles.

International audience2,2,2-Trifluoroethanol (TFE) + ionic liquids constitute new possible refrigerant/absorbent pairs in refrigeration and heat absorption systems. In this work, volumetric data were measured on these systems in order to estimate their potential as alternatives to the commonly used fluids. Original high-pressure (up to 40 MPa) density data of mixtures 2,2,2-trifluoroethanol (TFE) + 1-methyl-3-ethylimidazolium tetrafluoroborate, [EMIm][BF4], or 1-methyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, [BMIm][NTf2], have been measured in the temperature ranges 293.15–333.15 K and 283.15–333.15 K, respectively. Mixtures with [BMIm][NTf2] present higher densities and thus are more adequate for refrigeration systems. Excess molar volumes, VmE, and derived properties (isothermal compressibility, κT, and thermal expansion, αp) were calculated from experimental density data fitted to the Tait equation. αp and κT of the pure ionic liquids are smaller than those of the pure alcohol. Mixtures present derived properties similar to those of pure ionic liquids even at equimolar composition. From a technological aspect, these properties, being equivalent for both ionic liquids and most of their mixtures with TFE, will not be a criterion to select an absorbent–refrigerant pair. The excess molar volumes of the considered mixtures are small in absolute value and so can be considered as negligible when designing an absorption cycle. Finally, the PC-SAFT model was used to calculate the compressed densities. Acceptable results were obtained with trends as a function of temperature and pressure corresponding to what was experimentally observed. Using this model and a limited number of experimental data, the vapor pressures of the mixtures could be estimated with a reasonable precision

Mode and Characteristics of Arrhythmia Initiation in Idiopathic Ventricular Fibrillation: A THESIS Substudy.

There is limited information on the mode of arrhythmia initiation in idiopathic ventricular fibrillation (IVF). A non-pause-dependent mechanism has been suggested to be the rule. The aim of this study was to assess the mode and characteristics of initiation of polymorphic ventricular tachycardia (PVT) in patients with short or long-coupled PVT/IVF included in THESIS (THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey), a multicenter study involving 287 IVF patients treated with drugs or radiofrequency ablation. We reviewed the initiation of 410 episodes of ≥1 PVT triplet in 180 patients (58.3% females; age 39.6 ± 13.6 years) with IVF. The incidence of pause-dependency arrhythmia initiation (prolongation by &gt;20 ms of the preceding cycle length) was assessed. Most arrhythmias (n = 295; 72%) occurred during baseline supraventricular rhythm without ambient premature ventricular complexes (PVCs), whereas 106 (25.9%) occurred during baseline rhythm including PVCs. Nine (2.2%) arrhythmias occurred during atrial/ventricular pacing and were excluded from further analysis. Mode of PVT initiation was pause-dependent in 45 (15.6%) and 64 (60.4%) of instances in the first and second settings, respectively, for a total of 109 of 401 (27.2%). More than one type of pause-dependent and/or non-pause-dependent initiation (mean: 2.6) occurred in 94.4% of patients with ≥4 events. Coupling intervals of initiating PVCs were &lt;350 ms, 350-500 ms, and &gt;500 ms in 76.6%, 20.72%, and 2.7% of arrhythmia initiations, respectively. Pause-dependent initiation occurred in more than a quarter of arrhythmic episodes in IVF patients. PVCs having long (between 350 and 500 ms) and very long (&gt;500 ms) coupling intervals were observed at the initiation of nearly a quarter of PVT episodes

Mode and Characteristics of Arrhythmia Initiation in Idiopathic Ventricular Fibrillation: A THESIS Substudy.

BACKGROUND There is limited information on the mode of arrhythmia initiation in idiopathic ventricular fibrillation (IVF). A non-pause-dependent mechanism has been suggested to be the rule. OBJECTIVES The aim of this study was to assess the mode and characteristics of initiation of polymorphic ventricular tachycardia (PVT) in patients with short or long-coupled PVT/IVF included in THESIS (THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey), a multicenter study involving 287 IVF patients treated with drugs or radiofrequency ablation. METHODS We reviewed the initiation of 410 episodes of ≥1 PVT triplet in 180 patients (58.3% females; age 39.6 ± 13.6 years) with IVF. The incidence of pause-dependency arrhythmia initiation (prolongation by >20 ms of the preceding cycle length) was assessed. RESULTS Most arrhythmias (n = 295; 72%) occurred during baseline supraventricular rhythm without ambient premature ventricular complexes (PVCs), whereas 106 (25.9%) occurred during baseline rhythm including PVCs. Nine (2.2%) arrhythmias occurred during atrial/ventricular pacing and were excluded from further analysis. Mode of PVT initiation was pause-dependent in 45 (15.6%) and 64 (60.4%) of instances in the first and second settings, respectively, for a total of 109 of 401 (27.2%). More than one type of pause-dependent and/or non-pause-dependent initiation (mean: 2.6) occurred in 94.4% of patients with ≥4 events. Coupling intervals of initiating PVCs were 500 ms in 76.6%, 20.72%, and 2.7% of arrhythmia initiations, respectively. CONCLUSIONS Pause-dependent initiation occurred in more than a quarter of arrhythmic episodes in IVF patients. PVCs having long (between 350 and 500 ms) and very long (>500 ms) coupling intervals were observed at the initiation of nearly a quarter of PVT episodes