91 research outputs found

    Long-term effects of cerebellar anodal transcranial direct current stimulation (tDCS) on the acquisition and extinction of conditioned eyeblink responses

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    Cerebellar transcranial direct current stimulation (tDCS) has been reported to enhance the acquisition of conditioned eyeblink responses (CR), a form of associative motor learning. The aim of the present study was to determine possible long-term effects of cerebellar tDCS on the acquisition and extinction of CRs. Delay eyeblink conditioning was performed in 40 young and healthy human participants. On day 1, 100 paired CS (conditioned stimulus)–US (unconditioned stimulus) trials were applied. During the first 50 paired CS–US trials, 20 participants received anodal cerebellar tDCS, and 20 participants received sham stimulation. On days 2, 8 and 29, 50 paired CS–US trials were applied, followed by 30 CS-only extinction trials on day 29. CR acquisition was not significantly different between anodal and sham groups. During extinction, CR incidences were significantly reduced in the anodal group compared to sham, indicating reduced retention. In the anodal group, learning related increase of CR magnitude tended to be reduced, and timing of CRs tended to be delayed. The present data do not confirm previous findings of enhanced acquisition of CRs induced by anodal cerebellar tDCS. Rather, the present findings suggest a detrimental effect of anodal cerebellar tDCS on CR retention and possibly CR performance

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

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    Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters

    Search for a W ' boson decaying to a muon and a neutrino in pp collisions at √s =7 TeV

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    This is the Pre-Print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 ElsevierA new heavy gauge boson, W', decaying to a muon and a neutrino, is searched for in pp collisions at a centre-of-mass of 7 TeV. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 36 inverse picobarns. No significant excess of events above the standard model expectation is found in the transverse mass distribution of the muon-neutrino system. Masses below 1.40 TeV are excluded at the 95% confidence level for a sequential standard-model-like W'. The W' mass lower limit increases to 1.58 TeV when the present analysis is combined with the CMS result for the electron channel.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    Search for a heavy bottom-like quark in pp collisions at √s =7 TeV

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    This is the Pre-Print version of the Article. The official published version of the paper can be accessed from the link below - Copyright @ 2011 Elsevier.A search for pair-produced bottom-like quarks in pp collisions at sqrt(s) = 7 TeV is conducted with the CMS experiment at the LHC. The decay b' to tW is considered in this search. The b' b'-bar to tW^- t-bar W^+ process can be identified by the distinctive signature of trileptons and same-sign dileptons. With a data sample corresponding to an integrated luminosity of 34 inverse picobarns, no excess above the standard model background predictions is observed and a b' quark with a mass between 255 and 361 GeV/c^2 is excluded at the 95% confidence level.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    Measurement of the inclusive production cross sections for forward jets and for dijet events with one forward and one central jet in pp collisions at sqrt(s) = 7 TeV

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    The inclusive production cross sections for forward jets, as well for jets in dijet events with at least one jet emitted at central and the other at forward pseudorapidities, are measured in the range of transverse momenta pt = 35-150 GeV/c in proton-proton collisions at sqrt(s) = 7 TeV by the CMS experiment at the LHC. Forward jets are measured within pseudorapidities 3.2<|eta|<4.7, and central jets within the |eta|<2.8 range. The double differential cross sections with respect to pt and eta are compared to predictions from three approaches in perturbative quantum chromodynamics: (i) next-to-leading-order calculations obtained with and without matching to parton-shower Monte Carlo simulations, (ii) PYTHIA and HERWIG parton-shower event generators with different tunes of parameters, and (iii) CASCADE and HEJ models, including different non-collinear corrections to standard single-parton radiation. The single-jet inclusive forward jet spectrum is well described by all models, but not all predictions are consistent with the spectra observed for the forward-central dijet events.Comment: Submitted to the Journal of High Energy Physic

    Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

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    Anhydroalditols in the sugar analysis of methanolysates of alditols and oligosaccharide-alditols

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    In the context of the methanolysis procedure for sugar analysis, several alditols were investigated for their capacity to form anhydro derivatives in M methanolic HCl (24 h, 85°). Xylitol, D-arabinitol, L-fucitol, D-glucitol, galactitol, 2-acetamido-2-deoxy-D-galactitol, and the alditols of N-acetylneuraminic acid were very prone to form anhydrides, whereas 2-amino-2-deoxy-D-galactitol, 2-amino-2-deoxy-D-glucitol, D-mannitol, and 2-acetamido-2-deoxy-D-glucitol formed little anhydride. Anhydride formation was observed for the relevant alditols when present in reduced oligosaccharides. This finding is of importance in the quantification of sugar residues based on methanolysis, N-(re)acetylation, trimethylsilylation, and subsequent capillary g.l.c

    Determination of the absolute configuration of monosaccharides in complex carbohydrates by capillary G.L.C.

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    The absolute configuration of neutral monosaccharides, 2-acetamido-2-deoxy sugars, and uronic acids can be determined by capillary g.l.c. on SE-30 after glycosidation with (-)-2-butanol and protection of the remaining polar groups. The method is illustrated by application to mixtures of the constituent sugars of the capsular polysaccharide from Klebsiella type 57, alpha1-acid glycoprotein, mucus glycoproteins, and the methylated, acidic polysaccharide from the coccoliths of Emiliania huxleyi (Lohmann) Kamptner
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