1,101 research outputs found

    Improved diagnosis by automated macro‐ and micro‐anatomical region mapping of skin photographs

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    Background: The exact location of skin lesions is key in clinical dermatology. On one hand, it supports differential diagnosis (DD) since most skin conditions have specific predilection sites. On the other hand, location matters for dermatosurgical interventions. In practice, lesion evaluation is not well standardized and anatomical descriptions vary or lack altogether. Automated determination of anatomical location could benefit both situations. Objective: Establish an automated method to determine anatomical regions in clinical patient pictures and evaluate the gain in DD performance of a deep learning model (DLM) when trained with lesion locations and images. Methods: Retrospective study based on three datasets: macro-anatomy for the main body regions with 6000 patient pictures partially labelled by a student, micro-anatomy for the ear region with 182 pictures labelled by a student and DD with 3347 pictures of 16 diseases determined by dermatologists in clinical settings. For each dataset, a DLM was trained and evaluated on an independent test set. The primary outcome measures were the precision and sensitivity with 95% CI. For DD, we compared the performance of a DLM trained with lesion pictures only with a DLM trained with both pictures and locations. Results: The average precision and sensitivity were 85% (CI 84-86), 84% (CI 83-85) for macro-anatomy, 81% (CI 80-83), 80% (CI 77-83) for micro-anatomy and 82% (CI 78-85), 81% (CI 77-84) for DD. We observed an improvement in DD performance of 6% (McNemar test P-value 0.0009) for both average precision and sensitivity when training with both lesion pictures and locations. Conclusion: Including location can be beneficial for DD DLM performance. The proposed method can generate body region maps from patient pictures and even reach surgery relevant anatomical precision, e.g. the ear region. Our method enables automated search of large clinical databases and make targeted anatomical image retrieval possible

    Constraints on jet quenching in p-Pb collisions at root s(NN)=5.02 TeV measured by the event-activity dependence of semi-inclusive hadron-jet distributions

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    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high-transverse momentum trigger hadron in p-Pb collisions at root s(NN) = 5.02TeV. Jets are reconstructed from charged-particle tracks using the anti-k(T) algorithm with resolution parameter R = 0.2 and 0.4. A data-driven statistical approach is used to correct the uncorrelated background jet yield. Recoil jet distributions are reported for jet transverse momentum 15 < p(T,jet)(ch) < 50 GeV/c and are compared in various intervals of p-Pb event activity, based on charged-particle multiplicity and zero-degree neutral energy in the forward (Pb-going) direction. The semi-inclusive observable is self-normalized and such comparisons do not require the interpretation of p-Pb event activity in terms of collision geometry, in contrast to inclusive jet observables. These measurements provide new constraints on the magnitude of jet quenching in small systems at the LHC. In p-Pb collisions with high event activity, the average medium-induced out-of-cone energy transport for jets with R = 0.4 and 15 < p(T,jet)(ch) < 50 GeV/c is measured to be less than 0.4 GeV/c at 90% confidence, which is over an order of magnitude smaller than a similar measurement for central Pb-Pb collisions at root s(NN) = 2.76 TeV. Comparison is made to theoretical calculations of jet quenching in small systems, and to inclusive jet measurements in p-Pb collisions selected by event activity at the LHC and in d-Au collisions at RHIC.78395113CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSem informaçãoSem informaçãoSem informaçãoAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

    Long- and short-range correlations and their event-scale dependence in high-multiplicity pp collisions at 1as = 13 TeV

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    Two-particle angular correlations are measured in high-multiplicity proton-proton collisions at s = 13 TeV by the ALICE Collaboration. The yields of particle pairs at short-( 06\u3b7 3c 0) and long-range (1.6 < | 06\u3b7| < 1.8) in pseudorapidity are extracted on the near-side ( 06\u3c6 3c 0). They are reported as a function of transverse momentum (pT) in the range 1 < pT< 4 GeV/c. Furthermore, the event-scale dependence is studied for the first time by requiring the presence of high-pT leading particles or jets for varying pT thresholds. The results demonstrate that the long-range \u201cridge\u201d yield, possibly related to the collective behavior of the system, is present in events with high-pT processes as well. The magnitudes of the short- and long-range yields are found to grow with the event scale. The results are compared to EPOS LHC and PYTHIA 8 calculations, with and without string-shoving interactions. It is found that while both models describe the qualitative trends in the data, calculations from EPOS LHC show a better quantitative agreement for the pT dependency, while overestimating the event-scale dependency. [Figure not available: see fulltext.

    Inclusive J/ψ production at forward and backward rapidity in p-Pb collisions at √sNN=8.16 TeV

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    Inclusive J/psi production is studied in p-Pb interactions at a centre-of-mass energy per nucleon-nucleon collision sqrt(s_NN) = 8.16TeV, using the ALICE detector at the CERN LHC. The J/psi meson is reconstructed, via its decay to a muon pair, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and -4.46 < ycms < -2.96, where positive and negative ycms refer to the p-going and Pb-going direction, respectively. The transverse momentum coverage is pT < 20 GeV/c. In this paper, ycms- and pT-differential cross sections for inclusive J/psi production are presented, and the corresponding nuclear modification factors RpPb are shown. Forward results show a suppression of the J/psi yield with respect to pp collisions, concentrated in the region pT < 5 GeV/c. At backward rapidity no significant suppression is observed. The results are compared to previous measurements by ALICE in p-Pb collisions at sqrt(s_NN) = 5.02TeV and to theoretical calculations. Finally, the ratios RFB between forward- and backward-ycms RpPb values are shown and discussed

    Global baryon number conservation encoded in net-proton fluctuations measured in Pb–Pb collisions at √sNN = 2.76 TeV

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    Experimental results are presented on event-by-event net-proton fluctuation measurements in Pb–Pb collisions at √SNN=2.76 TeV, recorded by the ALICE detector at the CERN LHC. These measurements have as their ultimate goal an experimental test of Lattice QCD (LQCD) predictions on second and higher order cumulants of net-baryon distributions to search for critical behavior near the QCD phase boundary. Before confronting them with LQCD predictions, account has to be taken of correlations stemming from baryon number conservation as well as fluctuations of participating nucleons. Both effects influence the experimental measurements and are usually not considered in theoretical calculations. For the first time, it is shown that event-by-event baryon number conservation leads to subtle long-range correlations arising from very early interactions in the collisions.publishedVersio

    Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at √sNN=5.02 and 2.76 TeV

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    Measurements of anisotropic flow coefficients with two- and multi-particle cumulants for inclusive charged particles in Pb-Pb collisions at sqrt(s_NN) = 5.02 and 2.76TeV are reported in the pseudorapidity range |eta|< 0.8 and transverse momentum 0.2 < pT < 50 GeV/c. The full data sample collected by the ALICE detector in 2015 (2010), corresponding to an integrated luminosity of 12.7 (2.0) ub^-1 in the centrality range 0-80%, is analysed. Flow coefficients up to the sixth flow harmonic (v6) are reported and a detailed comparison among results at the two energies is carried out. The pT dependence of anisotropic flow coefficients and its evolution with respect to centrality and harmonic number n are investigated. An approximate power-law scaling of the form vn(pT) ~ pT^(n/3) is observed for all flow harmonics at low pT (0.2 < pT < 3 GeV/c). At the same time, the ratios vn/vm^(n/m) are observed to be essentially independent of pT for most centralities up to about pT = 10 GeV/c. Analysing the differences among higher-order cumulants of elliptic flow (v2), which have different sensitivities to flow fluctuations, a measurement of the standardised skewness of the event-by-event v2 distribution P(v2) is reported and constraints on its higher moments are provided. The Elliptic Power distribution is used to parametrise P(v2), extracting its parameters from fits to cumulants. The measurements are compared to different model predictions in order to discriminate among initial-state models and to constrain the temperature dependence of the shear viscosity to entropy-density ratio

    First measurement of the |t|-dependence of coherent J/ψ photonuclear production

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    ϒ production in p–Pb collisions at √sNN=8.16 TeV

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    ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio

    Measurement of Z(0)-boson production at large rapidities in Pb-Pb collisions at root s(NN)=5.02 TeV

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    The production of Z(0) bosons at large rapidities in Pb-Pb collisions at root s(NN) = 5.02 TeV is reported. Z(0) candidates are reconstructed in the dimuon decay channel (Z(0) -> mu(+) mu(-)), based on muons selected with pseudo-rapidity -4.0 20 GeV/c. The invariant yield and the nuclear modification factor, RAA, are presented as a function of rapidity and collision centrality. The value of R-AA for the 0-20% central Pb-Pb collisions is 0.67 +/- 0.11(stat.) +/- 0.03 (syst.) f 0.06(corr. syst.), exhibiting a deviation of 2.6 sigma from unity. The results are well-described by calculations that include nuclear modifications of the parton distribution functions, while the predictions using vacuum PDFs deviate from data by 2.3 sigma in the 0-90% centrality class and by 3 sigma in the 0-20% central collisions. (C) 2018 The Author(s). Published by Elsevier B.V.Peer reviewe

    First measurement of Ξc0 production in pp collisions at s=7 TeV

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    The production of the charm-strange baryon Csi0c is measured for the first time at the LHC via its semileptonic decay into e+Csi-νe in pp collisions at sqrt(s) = 7 TeV with the ALICE detector. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 1 &lt; pT &lt; 8 GeV/c at mid-rapidity, |y| &lt; 0.5. The transverse momentum dependence of the Csi0c baryon production relative to the D0 meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross- section ratio.The production of the charm-strange baryon Csi0c is measured for the first time at the LHC via its semileptonic decay into e+Csi-νe in pp collisions at sqrt(s) = 7 TeV with the ALICE detector. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 1 &lt; pT &lt; 8 GeV/c at mid-rapidity, |y| &lt; 0.5. The transverse momentum dependence of the Csi0c baryon production relative to the D0 meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross- section ratio
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