Massive color-octet bosons and the charge asymmetries of top quarks at hadron colliders

Several models predict the existence of heavy colored resonances decaying to top quarks in the TeV energy range that might be discovered at the LHC. In some of those models, moreover, a sizable charge asymmetry of top versus antitop quarks might be generated. The detection of these exotic resonances, however, requires selecting data samples where the top and the antitop quarks are highly boosted, which is experimentally very challenging. We asses that the measurement of the top quark charge asymmetry at the LHC is very sensitive to the existence of excited states of the gluon with axial-vector couplings to quarks. We use a toy model with general flavour independent couplings, and show that a signal can be detected with relatively not too energetic top and antitop quarks. We also compare the results with the asymmetry predicted by QCD, and show that its highest statistical significance is achieved with data samples of top-antitop quark pairs of low invariant masses.Comment: 20 page

Study of chip formation mechanism in CFRP turning

Carbon fiber reinforced polymer (CFRP) is a composite material much less studied than steel and other metals. This material class has excellent properties and allows weight reduction in structural parts; however, the CFRP turning has not the same popularity in the industry of other machining processes as milling and drilling. In this work, a literature survey was conducted to clarify the behavior of CFRP in machining, especially turning. This study evaluated the influence of the composition of the material and the fiber orientation angle, the surface damage during chip formation, and, mainly, parameters as cutting speed, feed rate, depth of cut, and tool geometry and material in the chip formation mechanisms. After discussion, some gaps are identified to be explored using PCD and tools under high cutting parameters conditions. After considering the evaluated studies, an experimental procedure is proposed for future execution, in which the effect of the cutting speed, depth of cut, and tool clearance angle

Budget-Aware Adapters for Multi-Domain Learning

Multi-Domain Learning (MDL) refers to the problem of learning a set of models derived from a common deep architecture, each one specialized to perform a task in a certain domain (e.g., photos, sketches, paintings). This paper tackles MDL with a particular interest in obtaining domain-specific models with an adjustable budget in terms of the number of network parameters and computational complexity. Our intuition is that, as in real applications the number of domains and tasks can be very large, an effective MDL approach should not only focus on accuracy but also on having as few parameters as possible. To implement this idea we derive specialized deep models for each domain by adapting a pre-trained architecture but, differently from other methods, we propose a novel strategy to automatically adjust the computational complexity of the network. To this aim, we introduce Budget-Aware Adapters that select the most relevant feature channels to better handle data from a novel domain. Some constraints on the number of active switches are imposed in order to obtain a network respecting the desired complexity budget. Experimentally, we show that our approach leads to recognition accuracy competitive with state-of-the-art approaches but with much lighter networks both in terms of storage and computation.Comment: ICCV 201

Charge asymmetries of top quarks: a window to new physics at hadron colliders

With the next start of LHC, a huge production of top quarks is expected. There are several models that predict the existence of heavy colored resonances decaying to top quarks in the TeV energy range. A peak in the differential cross section could reveal the existence of such a resonance, but this is experimentally challenging, because it requires selecting data samples where top and antitop quarks are highly boosted. Nonetheless, the production of such resonances might generate a sizable charge asymmetry of top versus antitop quarks. We consider a toy model with general flavour independent couplings of the resonance to quarks, of both vector and axial-vector kind. The charge asymmetry turns out to be a more powerful observable to detect new physics than the differential cross section, because its highest statistical significance is achieved with data samples of top-antitop quark pairs of low invariant masses

Type II superconductivity in SrPd2Ge2

Previous investigations have shown that SrPd2Ge2, a compound isostructural with "122" iron pnictides but iron- and pnictogen-free, is a conventional superconductor with a single s-wave energy gap and a strongly three-dimensional electronic structure. In this work we reveal the Abrikosov vortex lattice formed in SrPd2Ge2 when exposed to magnetic field by means of scanning tunneling microscopy and spectroscopy. Moreover, by examining the differential conductance spectra across a vortex and estimating the upper and lower critical magnetic fields by tunneling spectroscopy and local magnetization measurements, we show that SrPd2Ge2 is a strong type II superconductor with \kappa >> sqrt(2). Also, we compare the differential conductance spectra in various magnetic fields to the pair breaking model of Maki - de Gennes for dirty limit type II superconductor in the gapless region. This way we demonstrate that the type II superconductivity is induced by the sample being in the dirty limit, while in the clean limit it would be a type I superconductor with \kappa\ << sqrt(2), in concordance with our previous study (T. Kim et al., Phys. Rev. B 85, (2012)).Comment: 9 pages, 4 figure

Application of Direct Current Plasma Sintering Process in Powder Metallurgy

Direct current (dc) plasma-assisted sintering of metal parts is a promising and relatively new research and development field in powder metallurgy (PM). In the present entry, it is intended to introduce the reader to the main applications of the dc plasma sintering process in PM. To achieve this goal, the present entry is divided in a brief introduction and sections in which the bases of the dc plasma abnormal glow discharge regime and its influence in the sintering process are carefully treated. In this case, a clear language is purposely used to didactically introduce the reader to this “fascinating glow world”, the dc plasma-assisted sintering of metal parts, aiming to put in evidence the main points on physicochemical aspects of the plasma environment, basic knowledge of the plasma heating, and surface-related phenomena during dc plasma sintering of parts. All these aspects are treated considering the main techniques of the dc plasma-assisted sintering process applied to PM. Finally, some results on DC plasma heating, sintering and surface modification are presented

Métodos de ensino para o futsal escolar

Este trabalho é um relato de experiência acerca de estudos sobre os métodos de ensino utilizados no ensino dos esportes coletivos em uma escola da periferia de Santa Maria - RS. O trabalho especificamente está relacionado com a iniciação esportiva da modalidade do futsal

IDENTIFICAÇÃO DE MECANISMOS PARA ATENDER OS OBJETIVOS E PRINCÍPIOS DE GOVERNANÇA DE TI NA VISÃO DE PROFISSIONAIS DA ÁREA

IT Governance (ITG) mechanisms make tangible the high-level definitions on how the IT function of an organization must operate, in order to enable its practical application. The objective of this study is to identify mechanisms that can meet the objectives and principles of ITG. The study was based on literature review and organizational practices identified by means of data collection from Brazilian IT professionals. The motivation for this study is the importance of the obtainment of a list of ITG mechanisms using the same granularity. The study has a qualitative approach and was conducted through the analysis of publications, an electronic questionnaire and interviews using a semi-structured script. A set of 105 ITG mechanisms was identified by analyzing 13 publications. These mechanisms were grouped by similarity, reaching 46 mechanisms, which formed the basis for a survey of 26 professionals, especially CIOs and ITG analysts. Semi-structured interviews with 14 professionals were used to identify the perceived relationships among mechanisms, objectives and ITG principles. The result was a final list of mechanisms which is the main result of this study. Its main contribution is to identify ITG mechanisms on a common basis which may contribute to the continuity of ITG studies and the adoption of these mechanisms by organizations.Os mecanismos de Governança de TI (GTI) tornam tangíveis as definições de alto nível acerca de como a TI de uma organização deve operar, viabilizando a aplicação prática da GTI. O objetivo do estudo é identificar mecanismos que possam atender os objetivos e princípios de GTI na percepção de profissionais de TI brasileiros a partir da literatura e da prática organizacional, que compartilhem de granularidade e amplitude similares. A motivação do estudo é a necessidade de se obter listas de mecanismos que compartilhem granularidade, no intuito tanto de contribuir com estudos sobre o tema quanto com a adoção destes mecanismos pelas organizações. O estudo tem enfoque qualitativo e foi conduzido com análise de publicações anteriores, a aplicação de um questionário eletrônico e entrevistas semi-estrutu¬radas. A análise das publicações anteriores permitiu identificar 105 mecanismos de GTI presentes em treze publicações, que foram agrupados por similaridade de significado, che¬gando a 46 mecanismos. Estes constituíram a base para a realização de um levantamento com 26 profissionais, em especial gerentes deTI e analistas de GTI. Entrevistas semi-estruturadas com quatorze profissionais de GTI foram utilizadas na identificação das relações percebidas entre os mecanismos, os objetivos e os princípios da GTI. O resultado dessa etapa é a lista final de mecanismos, que constitui o principal resultado deste estudo. A contribuição do estudo é na identificação de uma lista de mecanismos de GTI em uma base comum, que pode contribuir para a continuidade dos estudos e para a adoção destes mecanismos pelas organizações

A utilização das tecnologias da informação no âmbito da previdência social: a inclusão excludente da internet aos segurados previdenciários / The use of information technologies in the framework of social security: the excluding inclusion of the internet to the private insured

A incorporação das tecnologias no âmbito da Previdência Social mostra-se adequada às necessidades de celeridade do processo administrativo. No entanto, a implantação do INSS Digital como ferramenta isolada, sem relacionar com as demais políticas públicas e sociais, revela-se inadequada, frente aos dados qualitativos apurados pelo PNAD-Contínua do IGBE. Assim, no presente artigo, analisou-se o papel da tecnologia no âmbito da Previdência Social, sob o viés do espaço de informação e de relação social, com a justificativa da necessidade de promover discussões políticas concentradas em questões sociais que afetam (in)diretamente toda sociedade. O objetivo é analisar a dinâmica social criada com a verticalização do INSS Digital na estrutura relacional com os segurados, tendo como referencial teórico Manuel Castells no processo relacional de poder. A metodologia utilizada foi à pesquisa quantitativa PNAD-Contínua do quarto trimestre de 2016 e os apontamentos acerca da inclusão da ferramenta do INSS Digital, como componentes de avaliação empírica, os quais evidenciaram variáveis importantes, sob o ponto de vista social, sobretudo no tocante a acessibilidade, ao desconhecimento digital e da deficiência e igualdade da cobertura da Rede Mundial de Internet.