704 research outputs found

    Amnesic Patients Show Superior Generalization in Category Learning

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    OBJECTIVE: Generalization is the application of existing knowledge to novel situations. Questions remain about the precise role of the hippocampus in this facet of learning, but a connectionist model by Gluck and Myers (1993) predicts that generalization should be enhanced following hippocampal damage. METHOD: In a two-category learning task, a group of amnesic patients (n=9) learned the training items to a similar level of accuracy as matched controls (n=9). Both groups then classified new items at various levels of distortion. RESULTS: The amnesic group showed significantly more accurate generalization to high-distortion novel items, a difference also present when compared to a larger group of unmatched controls (n=33). CONCLUSIONS: The model prediction of a broadening of generalization gradients in amnesia, at least for items near category boundaries, was supported by the results. Our study shows for the first time that amnesia can sometimes improve generalization

    Understood at Last?: A Memetic Analysis of Beethoven’s ‘Bloody Fist’

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    As a singular moment in the western canon, the opening of the recapitulation in the first movement of Beethoven’s Ninth Symphony has prompted a variety of structural and expressive readings. This paper explores its intertextual connections with Mozart’s Don Giovanni from a memetic perspective, outlining certain extra musical interpretations, including some related to Susan McClary’s controversial reading of the passage, one might infer from the strong musical connections

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Adaptive plasticity of killifish (Fundulus heteroclitus) embryos: dehydration-stimulated development and differential aquaporin-3 expression

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    13 pages, 7 figures, 3 tablesEmbryos of the marine killifish Fundulus heteroclitus are adapted to survive aerially. However, it is unknown if they are able to control development under dehydration conditions. Here, we show that air-exposed blastula embryos under saturated relative humidity were able to stimulate development, and hence the time of hatching was advanced with respect to embryos continuously immersed in seawater. Embryos exposed to air at later developmental stages did not hatch until water was added, while development was not arrested. Air-exposed embryos avoided dehydration probably because of their thickened egg envelope, although it suffered significant evaporative water loss. The potential role of aquaporins as part of the embryo response to dehydration was investigated by cloning the aquaporin-0 (FhAqp0), -1a (FhAqp1a), and -3 (FhAqp3) cDNAs. Functional expression in Xenopus laevis oocytes showed that FhaAqp1a was a water-selective channel, whereas FhAqp3 was permeable to water, glycerol, and urea. Expression of fhaqp0 and fhaqp1a was prominent during organogenesis, and their mRNA levels were similar between water- and air-incubated embryos. However, fhaqp3 transcripts were highly and transiently accumulated during gastrulation, and the protein product was localized in the basolateral membrane of the enveloping epithelial cell layer and in the membrane of ingressing and migrating blastomers. Interestingly, both fhaqp3 transcripts and FhAqp3 polypeptides were downregulated in air-exposed embryos. These data demonstrate that killifish embryos respond adaptively to environmental desiccation by accelerating development and that embryos are able to transduce dehydration conditions into molecular responses. The reduced synthesis of FhAqp3 may be one of these mechanisms to regulate water and/or solute transport in the embryo.This study was supported by the European Commission New and Emerging Science and Technologies (NEST) program (contract no. 012674-2 Sleeping Beauty) and by a grant from the Spanish Ministry of Education and Science (MEC; AGL2004-00316/ACU) to J. Cerda`. Participation of C. Zapater and F. Chauvigne´ was financed by a predoctoral fellowship from MEC (Spain) and by the European Commission [Marie Curie Research Training Network Aqua (glycero)porins, MRTN-CT-2006-035995], respectively.Peer reviewe

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the t-channel single top quark production cross section in pp collisions at √s =7 TeV

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    Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC

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    This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing

    Chemical injuries of the oesophagus: aetiopathological issues in Nigeria

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    <p>Abstract</p> <p>Background</p> <p>Chemical injuries of the oesophagus occur worldwide. There is paucity of information on aetiopathological profile of chemical injuries of the oesophagus in Nigeria.</p> <p>Aim</p> <p>The aim of the study was to determine the aetiopathological pattern of chemical injuries of the oesophagus in Nigeria.</p> <p>Materials and methods</p> <p>This is a multi-centre hospital based study in Lagos metropolis spanning a period of 10 years.</p> <p>The patients' bio data, substances ingested, sources of corrosives, reasons for ingesting corrosives and patients' mental state were recorded.</p> <p>Results</p> <p>In all, there were 78 patients (61 Males, 17 Females). The offending agents were acids in 55.1% of cases and it was accidental ingestion in 62 patients. The highest incidence of 57.6% was found in the middle 1/3 of the oesophagus.</p> <p>Conclusion</p> <p>Accidental ingestion of acids is the commonest cause of oesophageal injuries in Nigeria. The incidence of severe strictures necessitating oesophageal substitution could be reduced if early management of corrosive oesophagitis improves in Nigeria.</p
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