7,161 research outputs found

    Rastreamento de Jogadores de Futebol em Seqüência de Imagens

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    Este trabalho propõe um sistema de rastreamento visual de jogadores de futebol, o qual estima as trajetórias 2D em seqüências de imagens capturadas por câmeras fixas, instaladas ao redor de um campo de futebol. O rastreamento permite determinar diversos parâmetros como, por exemplo, a velocidade e a distância percorrida pelos jogadores durante uma partida, a região de maior movimentação da equipe no campo, etc. O sistema proposto segue uma abordagem probabilística, alcançando bons resultados iniciais. Os experimentos mostraram que uma implementação inicial do sistema, utilizando somente informação de variação da intensidade luminosa das imagens, já apresenta resultados eficazes e eficientes e permite vislumbrar melhorias significativas a serem desenvolvidas

    An orally active formulation of angiotensin-(1-7) produces an antithrombotic effect

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    INTRODUCTION AND OBJECTIVE: The heptapeptide angiotensin-(1-7) is a component of the renin-angiotensin system, which promotes many beneficial cardiovascular effects, including antithrombotic activity. We have recently shown that the antithrombotic effect of angiotensin-(1-7) involves receptor Mas-mediated NO-release from platelets. Here, we describe an orally active formulation based on angiotensin-(1-7) inclusion in cyclodextrin [Ang-(1-7)- CyD] as an antithrombotic agent. Cyclodextrins are pharmaceutical tools that are used to enhance drug stability, absorption across biological barriers and gastric protection. METHOD: To test the antithrombotic effect of Ang-(1-7)-CyD, thrombus formation was induced in the abdominal vena cava of spontaneously hypertensive rats that were pretreated either acutely or chronically with Ang-(1-7)-CyD. Male Mas-knockout and wild-type mice were used to verify the role of the Mas receptor on the effect of Ang-(1-7)-CyD. RESULTS: Acute or chronic oral treatment with Ang-(1-7)-CyD promoted an antithrombotic effect (measured by thrombus weight; all values are, respectively, untreated vs. treated animals) in spontaneously hypertensive rats (acute: 2.86 + 0.43 mg vs. 1.14 + 0.40 mg; chronic: 4.27 + 1.03 mg vs. 1.39 + 0.68 mg). This effect was abolished in Mas-knockout mice (thrombus weight in Mas wild-type: 0.76 + 0.10 mg vs. 0.37 + 0.02 mg; thrombus weight in Mas-knockout: 0.96 + 0.11 mg vs. 0.87 + 0.14 mg). Furthermore, the antithrombotic effect of Ang-(1-7)-CyD was associated with an increase in the plasma level of Angiotensin-(1-7). CONCLUSION: These results show for the first time that the oral formulation Ang-(1-7)-CyD has biological activity and produces a Mas-dependent antithrombotic effect

    Nearest-Neighbour Interaction from an Abelian Symmetry and Deviations from Hermiticity

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    We show that Nearest-Neighbour Interaction (NNI) textures for the quark mass matrices can be obtained through the introduction of an Abelian flavour symmetry. The minimal realisation requires a Z_4 symmetry in the context of a two Higgs doublet model. It is further shown that the NNI textures can be in agreement with all present experimental data on quark masses and mixings, provided one allows for deviations of Hermiticity in the quark mass matrices at the 20% level.Comment: 11 pages, 1 figure; references and minor corrections adde

    Spectro-ViT: A Vision Transformer Model for GABA-edited MRS Reconstruction Using Spectrograms

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    Purpose: To investigate the use of a Vision Transformer (ViT) to reconstruct/denoise GABA-edited magnetic resonance spectroscopy (MRS) from a quarter of the typically acquired number of transients using spectrograms. Theory and Methods: A quarter of the typically acquired number of transients collected in GABA-edited MRS scans are pre-processed and converted to a spectrogram image representation using the Short-Time Fourier Transform (STFT). The image representation of the data allows the adaptation of a pre-trained ViT for reconstructing GABA-edited MRS spectra (Spectro-ViT). The Spectro-ViT is fine-tuned and then tested using \textit{in vivo} GABA-edited MRS data. The Spectro-ViT performance is compared against other models in the literature using spectral quality metrics and estimated metabolite concentration values. Results: The Spectro-ViT model significantly outperformed all other models in four out of five quantitative metrics (mean squared error, shape score, GABA+/water fit error, and full width at half maximum). The metabolite concentrations estimated (GABA+/water, GABA+/Cr, and Glx/water) were consistent with the metabolite concentrations estimated using typical GABA-edited MRS scans reconstructed with the full amount of typically collected transients. Conclusion: The proposed Spectro-ViT model achieved state-of-the-art results in reconstructing GABA-edited MRS, and the results indicate these scans could be up to four times faster

    Quantum Conductance in Semimetallic Bismuth Nanocontacts

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    Electronic transport properties of bismuth nanocontacts are analyzed by means of a low temperature scanning tunneling microscope. The subquantum steps observed in the conductance versus elongation curves give evidence of atomic rearrangements in the contact. The underlying quantum nature of the conductance reveals itself through peaks in the conductance histograms. The shape of the conductance curves at 77 K is well described by a simple gliding mechanism for the contact evolution during elongation. The strikingly different behaviour at 4 K suggests a charge carrier transition from light to heavy ones as the contact cross section becomes sufficiently small.Comment: 5 pages including 4 figures. Accepted for publication in Phys. Rev. Let

    COVID-19 mental health care toolkit: an international collaborative effort by Early Career Psychiatrists section

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    The collaborative effort of an international research team from the Early Career Psychiatrists section of the World Psychiatry Association has brought about an easy-to-use, quick and stepwise mental health care toolkit for the identification and appropriate referral of those in need of mental health care during the pandemic. This simple guide can be applied in the general outpatient setting and is catered for all healthcare professionals, regardless of their expertise within the mental health field with minimal training. It is our hope that by incorporating this toolkit into our daily clinical care during the pandemic for high-risk patients and patients with non-specific complaints, we will be able to bridge the mental health gap present in our society

    Measurement of the Strong Coupling Constant from Inclusive Jet Production at the Tevatron pˉp\bar pp Collider

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    We report a measurement of the strong coupling constant, αs(MZ)\alpha_s(M_Z), extracted from inclusive jet production in ppˉp\bar{p} collisions at s=\sqrt{s}=1800 GeV. The QCD prediction for the evolution of αs\alpha_s with jet transverse energy ETE_T is tested over the range 40<ETE_T<450 GeV using ETE_T for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. In the text we discuss the data-theory comparison in the region from 250 to 450 GeV. The value of αs\alpha_s at the mass of the Z0Z^0 boson averaged over the range 40<ETE_T<250 GeV is found to be αs(MZ)=0.1178±0.0001(stat)0.0095+0.0081(exp.syst)\alpha_s(M_{Z})= 0.1178 \pm 0.0001{(\rm stat)}^{+0.0081}_{-0.0095}{\rm (exp. syst)}. The associated theoretical uncertainties are mainly due to the choice of renormalization scale (^{+6%}_{-4%}) and input parton distribution functions (5%).Comment: 7 pages, 3 figures, using RevTeX. Submitted to Physical Review Letter

    Measurement of the lepton charge asymmetry in W-boson decays produced in p-pbar collisions

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    We describe a measurement of the charge asymmetry of leptons from W boson decays in the rapidity range 0 enu, munu events from 110+/-7 pb^{-1}of data collected by the CDF detector during 1992-95. The asymmetry data constrain the ratio of d and u quark momentum distributions in the proton over the x range of 0.006 to 0.34 at Q2 \approx M_W^2. The asymmetry predictions that use parton distribution functions obtained from previously published CDF data in the central rapidity region (0.0<|y_l|<1.1) do not agree with the new data in the large rapidity region (|y_l|>1.1).Comment: 13 pages, 3 tables, 1 figur
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