2,510 research outputs found

    Projeto e desenvolvimento da arquitetura de um robô agrícola móvel

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    Parameters such as tolerance, scale and agility utilized in data sampling for using in Precision Agriculture required an expressive number of researches and development of techniques and instruments for automation. It is highlighted the employment of methodologies in remote sensing used in coupled to a Geographic Information System (GIS), adapted or developed for agricultural use. Aiming this, the application of Agricultural Mobile Robots is a strong tendency, mainly in the European Union, the USA and Japan. In Brazil, researches are necessary for the development of robotics platforms, serving as a basis for semi-autonomous and autonomous navigation systems. The aim of this work is to describe the project of an experimental platform for data acquisition in field for the study of the spatial variability and development of agricultural robotics technologies to operate in agricultural environments. The proposal is based on a systematization of scientific work to choose the design parameters utilized for the construction of the model. The kinematic study of the mechanical structure was made by the virtual prototyping process, based on modeling and simulating of the tension applied in frame, using the.Parâmetros, como tolerância, escala e agilidade empregados na amostragem de dados para uso em Agricultura de Precisão, exigem um expressivo número de pesquisas no desenvolvimento de instrumentos e técnicas para automação. Destacam-se a utilização de metodologias em sensoriamento remoto utilizadas em conjunto com o Sistema de Informação Geográfica (SIG), adaptados ou desenvolvidos para o uso agrícola. Visando a isso, a aplicação de Robôs Agrícolas Móveis é uma forte tendência, principalmente na União Europeia, EUA e Japão. No Brasil, pesquisas são necessárias para o desenvolvimento de plataformas robóticas, que sirvam de base para sistemas de navegação autônomos ou semiautônomos. O objetivo deste trabalho é descrever o projeto de uma plataforma experimental para a aquisição de dados em campo para o estudo da variabilidade espacial e desenvolvimento de tecnologias para operação de robôs em ambiente agrícola. A proposta baseia-se em uma sistematização de trabalhos científicos que norteiam a escolha dos parâmetros de projeto utilizados para a construção do modelo. O estudo cinemático da estrutura mecânica foi feito pelo processo de prototipagem virtual, baseado na modelagem e simulação das tensões aplicadas no chassi, utilizando o método dos elementos finitos, em função dos conceitos básicos de cinemática de robôs móveis e experiências em trabalhos anteriores.(FAPESP) São Paulo Research Foundation(CNPq) National Council of Scientific and Technological Developmen

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

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    A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

    Physical activity in pregnancy: a qualitative study of the beliefs of overweight and obese pregnant women

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    <p>Abstract</p> <p>Background</p> <p>Whilst there has been increasing research interest in interventions which promote physical activity during pregnancy few studies have yielded detailed insights into the views and experiences of overweight and obese pregnant women themselves. The qualitative study described in this paper aimed to: (i) explore the views and experiences of overweight and obese pregnant women; and (ii) inform interventions which could promote the adoption of physical activity during pregnancy.</p> <p>Methods</p> <p>The study was framed by a combined Subtle Realism and Theory of Planned Behaviour (TPB) approach. This enabled us to examine the hypothetical pathway between beliefs and physical activity intentions within the context of day to day life. The study sample for the qualitative study was chosen by stratified, purposive sampling from a previous study of physical activity measurements in pregnancy. Research participants for the current study were recruited on the basis of Body Mass Index (BMI) at booking and parity. Semi-structured, in-depth interviews were conducted with 14 overweight and obese pregnant women. Data analysis was undertaken using a Framework Approach and was informed by TPB.</p> <p>Results</p> <p>Healthy eating was often viewed as being of greater importance for the health of mother and baby than participation in physical activity. A commonly cited motivator for maintaining physical activity during pregnancy is an aid to reducing pregnancy-related weight gain. However, participants often described how they would wait until the postnatal period to try and lose weight. A wide range of barriers to physical activity during pregnancy were highlighted including both internal (physical and psychological) and external (work, family, time and environmental). The study participants also lacked access to consistent information, advice and support on the benefits of physical activity during pregnancy.</p> <p>Conclusions</p> <p>Interventions to encourage recommended levels of physical activity in pregnancy should be accompanied by accessible and consistent information about the positive effects for mother and baby. More research is required to examine how to overcome barriers to physical activity and to understand which interventions could be most effective for overweight/obese pregnant women. Midwives should be encouraged to do more to promote activity in pregnancy.</p

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    ACE2-angiotensin-(1-7)-Mas axis in renal ischaemia/reperfusion injury in rats

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    AngII (angiotensin II), ACE (angiotensin I-converting enzyme) and the AT(1) receptor (AngII type I receptor) are associated with the inflammatory process and microvascular dysfunction of AKI (acute kidney injury) induced by renal I/R (ischaemia/reperfusion). However, Ang-(1-7) [angiotensin-(1-7)], ACE2 (angiotensin I-converting enzyme 2) and the Mas receptor also play a role in renal disease models. Therefore, in the present study, we have examined the renal profile of Ang-(1-7), ACE2 and the Mas receptor in renal I/R and compared them with that of AngII, ACE and the AT(1) receptor. Male Wistar rats were submitted to left nephrectomy and ischaemia (45 min) followed by reperfusion (2 or 4 h) in the right kidney. At 4 h of reperfusion, renal AngII was increased (P < 0.01) and renal Ang-(1-7) was decreased substantially (P < 0.05), although plasma levels of both angiotensins were unchanged. in addition, renal I/R decreased the renal mRNA expression of renin (P < 0.05), AT(1) receptors (P < 0.001) and ACE2 (P < 0.05). At 2 and 4 h of reperfusion, renal ACE activity was reduced (P < 0.05). On the other hand, renal expression of the Mas receptor was greatly increased at 4 h of reperfusion (P < 0.01), which was confirmed by immunohistochemical and Western blot analysis. in conclusion, increased renal expression of the Mas receptor associated with changes in the RAS (renin-angiotensin-system)-related peptidases support an important role for the ACE2 Ang-(1-7) Mas axis in AKI.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Univ Fed Minas Gerais, Inst Biol Sci, Dept Physiol & Biophys, BR-31270901 Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Biophys, BR-04044020 São Paulo, SP, BrazilUniv Fed Minas Gerais, Dept Pathol, BR-31270901 Belo Horizonte, MG, BrazilUniv Fed Minas Gerais, Dept Microbiol, BR-31270901 Belo Horizonte, MG, BrazilUniv Fed Minas Gerais, Clin Pathol Unit COLTEC, BR-31270901 Belo Horizonte, MG, BrazilUniv Fed Minas Gerais, Dept Biochem, Inst Biol Sci, BR-31270901 Belo Horizonte, MG, BrazilUniv Fed Minas Gerais, Dept Pediat, Fac Med, BR-31270901 Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Biophys, BR-04044020 São Paulo, SP, BrazilCAPES: PRDEX2009CNPq: 8701480/1997-4FAPEMIG: CBS 2044/96Web of Scienc

    Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

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    Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate

    Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

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    Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) in ASDEX Upgrade (AUG), Alcator C-Mod, and JET-ILW are reviewed. Capabilities to diagnose and model the effect of DC biasing and associated impurity production at active antennas and on magnetic field connections to antennas are described. The experiments show that ICRF near-fields can lead not only to E×B convection, but also to modifications of the SOL density, which for Alcator C-Mod are limited to a narrow region near antenna. On the other hand, the SOL density distribution along with impurity sources can be tailored using local gas injection in AUG and JET-ILW with a positive effect on reduction of impurity sources. The technique of RF image current cancellation at antenna limiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna. Multiple observations confirmed the reduction of the impact of ICRF on the SOL and on total impurity production when the ratio of the power of the central straps to the total antenna power is in the range 0.6<Pcen_{cen}/Ptotal_{total}<0.8. Near-field calculations indicate that this fairly robust technique can be applied to the ITER ICRF antenna, enabling the mode of operation with reduced PWI. On the contrary, for the A2 antenna in JET-ILW the technique is hindered by RF sheaths excited at the antenna septum. Thus, in order to reduce the effect of ICRF power on PWI in a future fusion reactor, the antenna design has to be optimized along with design of plasmafacing components
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