65 research outputs found

    Feeling like a group after a natural disaster: Common ingroup identity and relations with outgroup victims among majority and minority young children

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    We conducted a field study to test whether the common ingroup identity model (Gaertner & Dovidio, 2000, reducing intergroup bias: The common ingroup identity model. Philadelphia, PA: Psychology Press) could be a useful tool to improve intergroup relations in the aftermath of a natural disaster. Participants were majority (Italian) and minority (immigrant) elementary school children (N = 517) living in the area struck by powerful earthquakes in May 2012. Results revealed that, among majority children, the perceived external threat represented by the earthquake was associated with greater perceptions of belonging to a common ingroup including both ingroup and outgroup. In turn, heightened one-group perceptions were associated with greater willingness to meet and help outgroup victims, both directly and indirectly via more positive outgroup attitudes. Among immigrant children, perceived disaster threat was not associated with any of the dependent variables; one-group perceptions were positively associated with outgroup attitudes, helping and contact intentions towards outgroup victims. Thus, onegroup perceptions after a natural disaster may promote more positive and supporting relations between the majority and the minority group. We discuss the theoretical and practical implications of the findings

    The neuron-astrocyte-microglia triad in a rat model of chronic cerebral hypoperfusion: Protective effect of dipyridamole

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    Chronic cerebral hypoperfusion during aging may cause progressive neurodegeneration as ischemic conditions persist. Proper functioning of the interplay between neurons and glia is fundamental for the functional organization of the brain. The aim of our research was to study the pathophysiological mechanisms, and particularly the derangement of the interplay between neurons and astrocytes-microglia with the formation of triads, in a model of chronic cerebral hypoperfusion induced by the 2-vessel occlusion (2VO) in adult Wistar rats (n=15). The protective effect of dipyridamole given during the early phases after 2VO (4 mg/kg/day i.v., the first 7 days after 2VO) was verified (n=15). Sham-operated rats (n=15) were used as controls. Immunofluorescent triple staining of neurons (NeuN), astrocytes (GFAP) and microglia (IBA1) was performed 90 days after 2VO. We found significantly higher amount of ectopic neurons, neuronal debris and apoptotic neurons in CA1 Str. Radiatum and Str. Pyramidale of 2VO rats. In CA1 Str. Radiatum of 2VO rats the amount of astrocytes (cells/mm2) did not increase. In some instances several astrocytes surrounded ectopic neurons and formed a micro scar around them. Astrocyte branches could infiltrate the cell body of ectopic neurons, and, together with activated microglia cells formed the triads. In the triad, significantly more numerous in CA1 Str. Radiatum of 2VO than in sham rats, astrocytes and microglia cooperated in the phagocytosis of ectopic neurons. These events might be common mechanisms underlying many neurodegenerative processes. The frequency to which they appear might depend upon, or might be the cause of, the burden and severity of neurodegeneration. Dypiridamole significantly reverted all the above described events. The protective effect of chronic administration of dipyridamole might be a consequence of its vasodilatory, antioxidant and anti-inflammatory role during the early phases after 2VO

    The jet of the BL Lac object PKS 0521 -365 in the near-IR : MAD adaptive optics observations

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    BL Lac objects are low--power active nuclei exhibiting a variety of peculiar properties that are caused by the presence of a relativistic jet and orientation effects. We present here adaptive optics near-IR images at high spatial resolution of the nearby BL Lac object PKS 0521-365, which is known to display a prominent jet both at radio and optical frequencies. The observations were obtained in Ks--band using the ESO multi-conjugated adaptive optics demonstrator at the Very Large Telescope. This allowed us to obtain images with 0.1 arcsec effective resolution. We performed a detailed analysis of the jet and its related features from the near-IR images, and combined them with images previously obtained with HST in the R band and by a re-analysis of VLA radio maps. We find a remarkable similarity in the structure of the jet at radio, near-IR, and optical wavelengths. The broad--band emission of the jet knots is dominated by synchrotron radiation, while the nucleus also exhibits a significant inverse Compton component. We discovered the near-IR counterpart of the radio hotspot and found that the near-IR flux is consistent with being a synchrotron emission from radio to X-ray. The bright red object (red-tip), detached but well aligned with the jet, is well resolved in the near-IR and has a linear light profile. Since it has no radio counterpart, we propose that it is a background galaxy not associated with the jet. The new adaptive optics near-IR images and previous observations at other frequencies allow us to study the complex environment around the remarkable BL Lac object PKS 0521-365. These data exemplify the capabilities of multi conjugate adaptive optics observations of extragalactic extended sources.Comment: accepted for publication in Astronomy and Astrophysics 9 pages. A & A 2009, in pres

    Morphological analysis of the Hippocampal region of aged rats, role of Clasmatodendrosis

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    Clasmatodendrosis is a phenomenon first described by Alzheimer in 1910, which was observed in aged nervous system and in the course of neurodegenerative diseases. It consists in the loss of astrocytic distal processes. The occurrence of clasmatodendrosis is frequently associated with an increase of autofluorescent aggregates in different cell types of nervous tissue. In this study we designed a calibrated excitation/emission method of spectral unmixing aimed to discriminate the fluorescence emitted by commercial fluorochrome-conjugated antibodies from the autofluorescent signal, by using confocal microscopy and multiphoton fluorescence lifetime imaging techniques. By this method, the immunolabeled GFAP localization in the CA1 Hippocampal region of aged rats was analyzed. Autofluorescent debris showed a strong positivity to GFAP labeling, suggesting that the detached fragments of clasmatodendrotic astrocytes might take part in the generation of these structures. By 3D confocal analysis we found that these aggregates, were located on neuronal cell surfaces, as well as inside the soma and that, in addition, the presence of autofluorescent aggregates seemed to be related with increased adhesion phenomena among neurons. These data were compared with those obtained in control adult rats and in rats infused with lipopolysaccharide (LPS) in the 4th ventricle to induce a chronic inflammatory state. The presence of autofluorescent aggregates was detected in LPS rats and also in control rats, even if they appeared smaller and with a lesser intensity as compared with the aged rats. These findings suggest that clasmatodendrosis is a process involving the interaction of neurons and astrocytes in a prolonged timespan of life. Its severity increases with aging or under inflammatory and/or neurodegenerative diseases. In conclusion, our results seem to suggest that clasmatodendrosis can affect neuron functionality not only due to a decreased astrocyte activity, but also by direct interaction of the detached astrocytic fragments with neuron somata

    Flow Index accurately identifies breaths with low or high inspiratory effort during pressure support ventilation

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    Background Flow Index, a numerical expression of the shape of the inspiratory flow-time waveform recorded during pressure support ventilation, is associated with patient inspiratory effort. The aim of this study was to assess the accuracy of Flow Index in detecting high or low inspiratory effort during pressure support ventilation and to establish cutoff values for the Flow index to identify these conditions. The secondary aim was to compare the performance of Flow index,of breathing pattern parameters and of airway occlusion pressure (P0.1) in detecting high or low inspiratory effort during pressure support ventilation. Methods Data from 24 subjects was included in the analysis, accounting for a total of 702 breaths. Breaths with high inspiratory effort were defined by a pressure developed by inspiratory muscles (Pmusc) greater than 10 cmH2O while breaths with low inspiratory effort were defined by a Pmusc lower than 5 cmH2O. The areas under the receiver operating characteristic curves of Flow Index and respiratory rate, tidal volume,respiratory rate over tidal volume and P0.1 were analyzed and compared to identify breaths with low or high inspiratory effort. Results Pmusc, P0.1, Pressure Time Product and Flow Index differed between breaths with high, low and intermediate inspiratory effort, while RR, RR/VT and VT/kg of IBW did not differ in a statistically significant way. A Flow index higher than 4.5 identified breaths with high inspiratory effort [AUC 0.89 (CI 95% 0.85–0.93)], a Flow Index lower than 2.6 identified breaths with low inspiratory effort [AUC 0.80 (CI 95% 0.76–0.83)]. Conclusions Flow Index is accurate in detecting high and low spontaneous inspiratory effort during pressure support ventilation

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

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    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

    Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at s√= 8 TeV with the ATLAS detector

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    A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3  fb−1 of integrated luminosity at s√=8  TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the standard model expectations. Limits are set on the mass scale in effective field theories that describe the interaction of dark matter and standard model particles, and on the cross section of Higgs production and decay to invisible particles. In addition, cross section limits on the anomalous production of W or Z bosons with large missing transverse momentum are set in two fiducial regions.We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC, and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST, and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR, and VSC CR, Czech Republic; DNRF, DNSRC, and Lundbeck Foundation, Denmark; EPLANET, ERC, and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG, and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP, and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW and NCN, Poland; GRICES and FCT, Portugal; MNE/IFA, Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF, and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society, and Leverhulme Trust, United Kingdom; U.S. DOE and NSF, United States of America. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK), and BNL (U.S.), and in the Tier-2 facilities worldwide

    Measurement of the top quark pair production charge asymmetry in proton-proton collisions at √s = 7 TeV using the ATLAS detector

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    This paper presents a measurement of the top quark pair ( tt¯ ) production charge asymmetry A C using 4.7 fb−1 of proton-proton collisions at a centre-of-mass energy √s = 7 TeV collected by the ATLAS detector at the LHC. A tt¯ -enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b-quark, is selected. A likelihood fit is used to reconstruct the tt¯ event kinematics. A Bayesian unfolding procedure is employed to estimate A C at the parton-level. The measured value of the tt¯ production charge asymmetry is A C = 0.006 ± 0.010, where the uncertainty includes both the statistical and the systematic components. Differential A C measurements as a function of the invariant mass, the rapidity and the transverse momentum of the tt¯ system are also presented. In addition, A C is measured for a subset of events with large tt¯ velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions
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