1,978 research outputs found

    Prefood and Preshock Stimulus Effects on Fixed-Interval and Fixed-Ratio Responding

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    Two experiments were designed to study with rats the effects of a preshock stimulus (Experiment I) and a prefood stimulus (Experiment II) on lever pressing maintained by a multiple fixed-ratio 100 fixed-interval 90 s schedule of food reinforcement. The purpose was to determine if the effects of these stimuli, identified as Pavlovian Css, were related to where within each component\u27s schedule they occurred; early in a ratio interval, or late in a ratio or interval. Experiment I indicated that when the CS was presented early in a ratio or interval, or late in an interval, nearly equivalent suppression occurred for contingent and noncontingent control subjects. When the CS was presented late in a ratio, suppression was greatest for the contingent subjects. One subject, who received the CS-US pair on-the-baseline, showed suppression during the CS, and depressed responding in the absence of the CS, at both points within each component schedule. These effects were accompanied by post-CS suppression and by a sharp increase in FR PRPs and work times. Experiment II showed a generally small effect of the CS on responding at both points within each component schedule; this was seen for contingent and noncontingent control subjects alike. In contrast, on-the-baseline training produced an increase in initial FR and FI responding during, and in the absence of, the CS that was accompanied by a decrease in FR and FI PRPs. In contrast, responding late in a ratio or interval was minimally affected. The present Experiment I provides the basis for rejecting earlier accounts of negative conditioned suppression of FR and FI maintained responding. In addition, Experiment I yielded new evidence regarding a) off- vs on-the-baseline conditioning procedures, and c) residual baseline effects. The present Experiment II provides evidence relevant to positive conditioned suppression of FR and FI maintained responding. In addition to yielding new information regarding this phenomenon, these data, together with a portion of those from Experiment I, question the traditional assumption that conditioned suppression (or acceleration) results from the contingent relation between a CS and a US

    Commentary - Further Directions For Gambling Research

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    Altering Probability Discounting in a Gambling Simulation

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    In gambling, our decisions regarding what gambles to take and how much we are willing to wager might, in part, be influenced by our histories with respect to gambling outcomes. Given a less temporally-distant history with gambling that favors losses, wins, or breaking even may create alterations in one’s discounting pattern, albeit most likely temporary. Given the topographical similarity between gambling procedures and probabilistic discounting tasks, probability discounting was used to assess potential changes in discounting resulting from a gambling task designed specifically for this study. Probabilistic discounting patterns for 38 undergraduate students before and after exposure to a simulated die-rolling task were analyzed, and results of follow-up analyses supported the notion that probabilistic discounting patterns can be changed by gambling outcomes. Implications and limitations are discussed

    Measurements of branching fraction ratios and CP-asymmetries in suppressed B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^- decays

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    We report the first reconstruction in hadron collisions of the suppressed decays B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^-, sensitive to the CKM phase gamma, using data from 7 fb^-1 of integrated luminosity collected by the CDF II detector at the Tevatron collider. We reconstruct a signal for the B^- -> D(-> K^+ pi^-)K^- suppressed mode with a significance of 3.2 standard deviations, and measure the ratios of the suppressed to favored branching fractions R(K) = [22.0 \pm 8.6(stat)\pm 2.6(syst)]\times 10^-3, R^+(K) = [42.6\pm 13.7(stat)\pm 2.8(syst)]\times 10^-3, R^-(K)= [3.8\pm 10.3(stat)\pm 2.7(syst]\times 10^-3, as well as the direct CP-violating asymmetry A(K) = -0.82\pm 0.44(stat)\pm 0.09(syst) of this mode. Corresponding quantities for B^- -> D(-> K^+ pi^-)pi^- decay are also reported.Comment: 8 pages, 1 figure, accepted by Phys.Rev.D Rapid Communications for Publicatio

    Complications associated with transobturator sling procedures: analysis of 233 consecutive cases with a 27 months follow-up

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    <p>Abstract</p> <p>Backround</p> <p>The transobturator tape procedure (TOT) is an effective surgical treatment of female stress urinary incontinence. However data concerning safety are rare, follow-up is often less than two years, and complications are probably underreported. The aim of this study was to describe early and late complications associated with TOT procedures and identify risk factors for erosions.</p> <p>Methods</p> <p>It was a 27 months follow-up of a cohort of 233 women who underwent TOT with three different types of slings (Aris<sup>®</sup>, Obtape<sup>®</sup>, TVT-O<sup>®</sup>). Follow-up information was available for 225 (96.6%) women.</p> <p>Results</p> <p>There were few per operative complications. Forty-eight women (21.3%) reported late complications including <it>de novo </it>or worsening of preexisting urgencies (10.2%), perineal pain (2.2%), <it>de novo </it>dyspareunia (9%), and vaginal erosion (7.6%). The risk of erosion significantly differed between the three types of slings and was 4%, 17% and 0% for Aris<sup>®</sup>, Obtape<sup>® </sup>and TVT-O<sup>® </sup>respectively (P = 0.001). The overall proportion of women satisfied by the procedure was 72.1%. The percentage of women satisfied was significantly lower in women who experienced erosion (29.4%) compared to women who did not (78.4%) (RR 0.14, 95% CI 0.05-0.38, P < 0.001).</p> <p>Conclusion</p> <p>Late post operative complications are relatively frequent after TOT and can impair patient's satisfaction. Women should be informed of these potential complications preoperatively and require careful follow-up after the procedure. Choice of the safest sling material is crucial as it is a risk factor for erosion.</p

    Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

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    Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Peer reviewe

    Search for B_s --> mu+mu- and B_d --> mu+mu- Decays with CDF II

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    A search has been performed for B_s --> mu+mu- and B_d --> mu+mu- decays using 7/fb of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B_d candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of BF(B_d-->mu+mu-) < 6.0E-9 at 95% confidence level. We observe an excess of B_s candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B_s --> mu+mu- could produce such an excess or larger is 1.9%. These data are used to determine BF(B_s-->mu+mu-) = (1.8^{+1.1}_{-0.9})E-8 and provide an upper limit of BF(B_s -->mu+mu-) < 4.0E-8 at 95% confidence level.Comment: 7 pages, 1 figure; version accepted by PR

    Energy Resolution Performance of the CMS Electromagnetic Calorimeter

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    The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals
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