204 research outputs found
Automatic classification of autism spectrum disorder in children using cortical thickness and support vector machine
Objective: Autism spectrum disorder (ASD) is a neurodevelopmental condition with a heterogeneous phenotype. The role of biomarkers in ASD diagnosis has been highlighted; cortical thickness has proved to be involved in the etiopathogenesis of ASD core symptoms. We apply support vector machine, a supervised machine learning method, in order to identify specific cortical thickness alterations in ASD subjects. Methods: A sample of 76 subjects (9.5 \ub1 3.4 years old) has been selected, 40 diagnosed with ASD and 36 typically developed subjects. All children underwent a magnetic resonance imaging (MRI) examination; T1-MPRAGE sequences were analyzed to extract features for the characterization and parcellation of regions of interests (ROI); average cortical thickness (CT) has been measured for each ROI. For the classification process, the extracted features were used as input for a classifier to identify ASD subjects through a "learning by example" procedure; the features with best performance was then selected by "greedy forward-feature selection." Finally, this model underwent a leave-one-out cross-validation approach. Results: From the training set of 68 ROIs, five ROIs reached accuracies of over 70%. After this phase, we used a recursive feature selection process in order to identify the eight features with the best accuracy (84.2%). CT resulted higher in ASD compared to controls in all the ROIs identified at the end of the process. Conclusion: We found increased CT in various brain regions in ASD subjects, confirming their role in the pathogenesis of this condition. Considering the brain development curve during ages, these changes in CT may normalize during development. Further validation on a larger sample is required
Promoting the learning of modern and contemporary physics in high schools in informal and non-formal contexts
In this paper, we introduce active learning strategies developed by the Educational Division of the Physics Department of the University of Cagliari to
promote the learning of modern and contemporary physics (e.g., general relativity,
particle physics, cosmology, and related topics) in high schools in informal and non-formal contexts. We discuss their features and potential role in facilitating science and physics instruction by integrating pedagogical theory and education research. We illustrate our theoretical framework and the methodologies we implemented to design specific educational strategies - and the evaluation of their effectiveness - to improve motivation, curiosity, and interest in modern and contemporary physics, as well as bring these topics more extensively to high schools. Finally, examples of the proposed educational activities are presented and their implications in informal and non-formal contexts are discussed
Increased gyrification in schizophrenia and non affective first episode of psychosis
Prefrontal cortex gyrification has been suggested to be altered in patients with schizophrenia and first episode psychosis. Therefore, it may represent a possible trait marker for these illnesses and an indirect evidence of a disrupted underlying connectivity. The aim of this study was to add further evidence to the existing literature on the role of prefrontal gyrification in psychosis by carrying out a study on a sizeable sample of chronic patients with schizophrenia and non-affective first-episode psychosis (FEP-NA) patients. Methods: Seventy-two patients with schizophrenia, 51 FEP-NA patients (12 who later develop schizophrenia) and 95 healthy controls (HC) underwent magnetic resonance imaging (MRI). Cortical folding was quantified using the automated gyrification index (GI). GI values were compared among groups and related to clinical variables. Results: Both FEP-NA and patients with schizophrenia showed a higher mean prefrontal GI compared to HC (all p. <. 0.05). Interestingly, no differences have been observed between the two patients groups as well as between FEP-NA patients who did and did not develop schizophrenia. Conclusions: Our results suggest the presence of a shared aberrant prefrontal GI in subjects with both schizophrenia and first-episode psychosis. These findings support the hypothesis that altered GI represents a neurodevelopmental trait marker for psychosis, which may be involved in the associated neurocognitive deficits
Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires
The production of tt⟠, W+bb⟠and W+cc⟠is studied in the forward region of protonâproton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fbâ1 . The W bosons are reconstructed in the decays WââÎœ , where â denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of , and is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 0.02 \mbox{fb}^{-1}. The bosons are reconstructed in the decays , where denotes muon or electron, while the and quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states
A first study of CP violation in the decay modes and , where labels a or meson and labels a or meson, is performed. The analysis uses the LHCb data set collected in collisions, corresponding to an integrated luminosity of 3 fb. The analysis is sensitive to the CP-violating CKM phase through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of using other decay modes
Study of the rare B-s(0) and B-0 decays into the pi(+) pi(-) mu(+) mu(-) final state
A search for the rare decays and is performed in a data set corresponding to an integrated luminosity of 3.0 fb collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/ and with muon pairs that do not originate from a resonance are considered. The first observation of the decay and the first evidence of the decay are obtained and the branching fractions are measured to be and , where the third uncertainty is due to the branching fraction of the decay , used as a normalisation.A search for the rare decays Bs0âÏ+ÏâÎŒ+ÎŒâ and B0âÏ+ÏâÎŒ+ÎŒâ is performed in a data set corresponding to an integrated luminosity of 3.0 fbâ1 collected by the LHCb detector in protonâproton collisions at centre-of-mass energies of 7 and 8 TeV . Decay candidates with pion pairs that have invariant mass in the range 0.5â1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0âÏ+ÏâÎŒ+ÎŒâ and the first evidence of the decay B0âÏ+ÏâÎŒ+ÎŒâ are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0âÏ+ÏâÎŒ+ÎŒâ)=(8.6±1.5 (stat)±0.7 (syst)±0.7(norm))Ă10â8 and B(B0âÏ+ÏâÎŒ+ÎŒâ)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))Ă10â8 , where the third uncertainty is due to the branching fraction of the decay B0âJ/Ï(âÎŒ+ÎŒâ)Kâ(892)0(âK+Ïâ) , used as a normalisation.A search for the rare decays Bs0âÏ+ÏâÎŒ+ÎŒâ and B0âÏ+ÏâÎŒ+ÎŒâ is performed in a data set corresponding to an integrated luminosity of 3.0 fbâ1 collected by the LHCb detector in protonâproton collisions at centre-of-mass energies of 7 and 8 TeV . Decay candidates with pion pairs that have invariant mass in the range 0.5â1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0âÏ+ÏâÎŒ+ÎŒâ and the first evidence of the decay B0âÏ+ÏâÎŒ+ÎŒâ are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0âÏ+ÏâÎŒ+ÎŒâ)=(8.6±1.5 (stat)±0.7 (syst)±0.7(norm))Ă10â8 and B(B0âÏ+ÏâÎŒ+ÎŒâ)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))Ă10â8 , where the third uncertainty is due to the branching fraction of the decay B0âJ/Ï(âÎŒ+ÎŒâ)Kâ(892)0(âK+Ïâ) , used as a normalisation.A search for the rare decays and is performed in a data set corresponding to an integrated luminosity of 3.0 fb collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/ and with muon pairs that do not originate from a resonance are considered. The first observation of the decay and the first evidence of the decay are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be and , where the third uncertainty is due to the branching fraction of the decay , used as a normalisation
Observation of the B0 â Ï0Ï0 decay from an amplitude analysis of B0 â (Ï+Ïâ)(Ï+Ïâ) decays
Protonâproton collision data recorded in 2011 and 2012 by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fbâ1 , are analysed to search for the charmless B0âÏ0Ï0 decay. More than 600 B0â(Ï+Ïâ)(Ï+Ïâ) signal decays are selected and used to perform an amplitude analysis, under the assumption of no CP violation in the decay, from which the B0âÏ0Ï0 decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0âÏ0Ï0 decays yielding a longitudinally polarised final state is measured to be fL=0.745â0.058+0.048(stat)±0.034(syst) . The B0âÏ0Ï0 branching fraction, using the B0âÏKâ(892)0 decay as reference, is also reported as B(B0âÏ0Ï0)=(0.94±0.17(stat)±0.09(syst)±0.06(BF))Ă10â6
Measurement of the (eta c)(1S) production cross-section in proton-proton collisions via the decay (eta c)(1S) -> p(p)over-bar
The production of the state in proton-proton collisions is probed via its decay to the final state with the LHCb detector, in the rapidity range GeV/c. The cross-section for prompt production of mesons relative to the prompt cross-section is measured, for the first time, to be at a centre-of-mass energy TeV using data corresponding to an integrated luminosity of 0.7 fb, and at TeV using 2.0 fb. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the and decays to the final state. In addition, the inclusive branching fraction of -hadron decays into mesons is measured, for the first time, to be , where the third uncertainty includes also the uncertainty on the inclusive branching fraction from -hadron decays. The difference between the and meson masses is determined to be MeV/c.The production of the state in proton-proton collisions is probed via its decay to the final state with the LHCb detector, in the rapidity range . The cross-section for prompt production of mesons relative to the prompt cross-section is measured, for the first time, to be at a centre-of-mass energy using data corresponding to an integrated luminosity of 0.7Â fb , and at using 2.0Â fb . The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the and decays to the final state. In addition, the inclusive branching fraction of -hadron decays into mesons is measured, for the first time, to be , where the third uncertainty includes also the uncertainty on the inclusive branching fraction from -hadron decays. The difference between the and meson masses is determined to be .The production of the state in proton-proton collisions is probed via its decay to the final state with the LHCb detector, in the rapidity range GeV/c. The cross-section for prompt production of mesons relative to the prompt cross-section is measured, for the first time, to be at a centre-of-mass energy TeV using data corresponding to an integrated luminosity of 0.7 fb, and at TeV using 2.0 fb. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the and decays to the final state. In addition, the inclusive branching fraction of -hadron decays into mesons is measured, for the first time, to be , where the third uncertainty includes also the uncertainty on the inclusive branching fraction from -hadron decays. The difference between the and meson masses is determined to be MeV/c
Search for the lepton flavour violating decay tau(-) -> mu(-)mu(+)mu(-)
A search for the lepton flavour violating decay is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of 1.0 fb of proton-proton collisions at a centre-of-mass energy of 7 TeV and 2.0 fb at 8 TeV. No evidence is found for a signal, and a limit is set at 90% confidence level on the branching fraction, .A search for the lepton flavour violating decay Ï â ÎŒ ÎŒ ÎŒ is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of 1.0 fb of proton-proton collisions at a centre-of-mass energy of 7 TeV and 2.0 fb at 8 TeV. No evidence is found for a signal, and a limit is set at 90% confidence level on the branching fraction, .A search for the lepton flavour violating decay is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of of proton-proton collisions at a centre-of-mass energy of and at . No evidence is found for a signal, and a limit is set at confidence level on the branching fraction,
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