805 research outputs found

    Measurement of cognitive bias and cortisol levels to evaluate the effects of space restriction on captive collared peccary (Mammalia, Tayassuidae)

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    We use the judgement-bias paradigm to evaluate whether space restriction in metabolism pens affects the emotional state of collared peccary (Pecari tajacu) during a nutritional experiment. We trained individual adult males to ‘go’ to a specific location within 30 s when a positive auditory cue (whistle; CS+) was given in order to receive cassava root pieces as a reward, and to ‘no-go’ when a negative cue (caxixi percussion instrument; CS−) was sounded to avoid punishment (jet of water) and no reward. An ‘ambiguous’ auditory cue (a drumstick hitting an aluminum plate; CSA) was presented to probe decision-making under ambiguity. Individuals were subjected to five 8-day housing conditions in the order: H1 (control-no space restriction-metabolism pen and additional area), H2 space restriction without environmental enrichment (metabolism pen only), H3 (control-no space restriction), H4 (space restriction with environmental enrichment), and H5 (control-no space restriction). On the eighth day of each housing condition, each animal was exposed to 10 judgement bias trials of each of the three cue types: CS+, CS−, and CSA. We recorded whether animals showed the ‘go’ or ‘no-go’ response after each type of cue and collected fecal samples to assess fecal glucocorticoid metabolite concentrations. Peccaries learnt to discriminate CS+ and CS− and maintained this discrimination during the five housing conditions tested. The response to the ambiguous cue (CSA) varied according to the housing condition. During H1, the peccaries made a similar proportion of ‘go’ responses to all three types of cue (Ps > 0.07). During H2 and H3, ‘go’ responses to CSA and CS− cues occurred in similar proportions (Ps > 0.70), but peccaries showed more go responses to CS+ (Ps < 0.03) indicating that they were responding to CSA as if it were more likely to predict the waterjet than food. During H4 and H5, peccaries again made a similar proportion of ‘go’ responses to all three types of cue, as in H1. During H2 and H3, fecal glucocorticoid metabolite concentrations were higher than during the other tests (208.0 ± 16.4 vs. 141.6 ± 25.9 ngg−1 dry feces, Ps < 0.03). Our results suggest that space restriction may induce physiological stress and influence judgement bias and affective state in peccaries, and that these effects may be offset by environmental enrichment. However, the possibility of a general habituation to the housing conditions across time cannot be ruled out

    The structure and dynamics of young star clusters: King 16, NGC 1931, NGC 637 and NGC 189

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    In this paper, using 2MASS photometry, we study the structural and dynamical properties of four young star clusters viz. King 16, NGC 1931, NGC 637 and NGC 189. For the clusters King 16, NGC 1931, NGC 637 and NGC 189, we obtain the limiting radii of 7', 12', 6' and 5' which correspond to linear radii of 3.6 pc, 8.85 pc, 3.96 pc and 2.8 pc respectively. The reddening values E(BV)E(B-V) obtained for the clusters are 0.85, 0.65--0.85, 0.6 and 0.53 and their true distances are 1786 pc, 3062 pc, 2270 pc and 912 pc respectively. Ages of the clusters are 6 Myr, 4 Myr, 4 Myr and 10 Myr respectively. We compare their structures, luminosity functions and mass functions (ϕ(M)=dN/dMM(1+χ)\phi(M) = dN/dM \propto M^{-(1+\chi)}) to the parameter τ=tage/trelax\tau = t_{age}/t_{relax} to study the star formation process and the dynamical evolution of these clusters. We find that, for our sample, mass seggregation is observed in clusters or their cores only when the ages of the clusters are comparable to their relaxation times (τ1\tau \geq 1). These results suggest mass seggregation due to dynamical effects. The values of χ\chi, which characterise the overall mass functions for the clusters are 0.96 ±\pm 0.11, 1.16 ±\pm 0.18, 0.55 ±\pm 0.14 and 0.66 ±\pm 0.31 respectively. The change in χ\chi as a function of radius is a good indicator of the dynamical state of clusters.Comment: Accepted for publication in Astrophysics & Space Scienc

    Magnetic Branes in Gauss-Bonnet Gravity

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    We present two new classes of magnetic brane solutions in Einstein-Maxwell-Gauss-Bonnet gravity with a negative cosmological constant. The first class of solutions yields an (n+1)(n+1)-dimensional spacetime with a longitudinal magnetic field generated by a static magnetic brane. We also generalize this solution to the case of spinning magnetic branes with one or more rotation parameters. We find that these solutions have no curvature singularity and no horizons, but have a conic geometry. In these spacetimes, when all the rotation parameters are zero, the electric field vanishes, and therefore the brane has no net electric charge. For the spinning brane, when one or more rotation parameters are non zero, the brane has a net electric charge which is proportional to the magnitude of the rotation parameter. The second class of solutions yields a spacetime with an angular magnetic field. These solutions have no curvature singularity, no horizon, and no conical singularity. Again we find that the net electric charge of the branes in these spacetimes is proportional to the magnitude of the velocity of the brane. Finally, we use the counterterm method in the Gauss-Bonnet gravity and compute the conserved quantities of these spacetimes.Comment: 17 pages, No figure, The version to be published in Phys. Rev.

    Two-body ZZ' decays in the minimal 331 model

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    The two-body decays of the extra neutral boson Z_2 predicted by the minimal 331 model are analyzed. At the three-level it can decay into standard model particles as well as exotic quarks and the new gauge bosons predicted by the model. The decays into a lepton pair are strongly suppressed, with Br(Z2>l+l) 102Br(Z_2 --> l^+l^-) ~ 10^{-2} and Br(Z2>νˉlν) 103Br(Z_2 --> \bar{\nu}_l \nu) ~ 10^{-3}. In the bosonic sector, Z_2 would decay mainly into a pair of bilepton gauge bosons, with a branching ratio below the 0.1 level. The Z_2 boson has thus a leptophobic and bileptophobic nature and it would decay dominantly into quark pairs. The anomaly-induced decays Z2>Z1γZ_2 --> Z_1\gamma and Z2>Z1Z1Z_2 --> Z_1Z_1, which occurs at the one-loop level are studied. It is found that Br(Z2>Z1γ) 109Br(Z_2 --> Z_1\gamma) ~ 10^{-9} and Br(Z2>Z1Z1) 106Br(Z_2 --> Z_1Z_1) ~ 10^{-6} at most. As for the Z2>W+WZ_2 --> W^+W^- and Z2>Z1HZ_2 --> Z_1H decays, with H a relatively light Higgs boson, they are induced via Z'-Z mixing. It is obtained that Br(Z2>W+W) 102Br(Z_2 --> W^+W^-) ~ 10^{-2} and Br(Z2>Z1H) 105Br (Z_2 --> Z_1H) ~ 10^{-5}. We also examine the flavor changing neutral current decays Z2>tcZ_2 --> tc and Z2>tuZ_2 --> tu, which may have branching fractions as large as 10310^{-3} and 10510^{-5}, respectively, and thus may be of phenomenological interest.Comment: 14 pages, 3 figures, submitted to Physical Review

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

    Quantifying the Uncertainty of Land Surface Temperature Retrievals From SEVIRI/Meteosat

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    Impact of Enhanced Recovery after Surgery<sup>®</sup> Protocol Compliance on Length of Stay, Bowel Recovery and Complications after Radical Cystectomy.

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    Despite existing standardized surgical techniques and the development of new perioperative care protocols, radical cystectomy (RC) morbidity remains a serious challenge for urologists. Postoperative ileus (POI) is one of the most common postoperative complications, often leading to a longer length of stay (LOS). The aim of our study was to assess the impact of compliance to the Enhanced Recovery After Surgery (ERAS &lt;sup&gt;®&lt;/sup&gt; ) protocol on bowel recovery, 30-day complications and LOS after RC for bladder cancer (BC). Data from consecutive patients undergoing RC for BC within an ERAS &lt;sup&gt;®&lt;/sup&gt; dedicated protocol were analyzed. Exclusion criteria were urinary diversion other than ileal conduit and palliative RC. Patients were divided into two groups according to their compliance (A: low-compliance and B: high-compliance). ERAS &lt;sup&gt;®&lt;/sup&gt; compliance was extracted from the ERAS &lt;sup&gt;®&lt;/sup&gt; Interactive Audit System (EIAS) database. Postoperative complications were prospectively recorded by a dedicated study nurse 30 days after RC. POI was defined as the placement of a nasogastric tube. Logistic regression analysis was used to identify predictors of 30-day complications and POI. After considering the exclusion criteria, 108 patients were included for the final analysis. The median global compliance to the ERAS &lt;sup&gt;®&lt;/sup&gt; protocol was 61%. A total of 78 (72%) patients had a compliance &lt;65% (group A), while the remaining 30 (28%) had a compliance &gt;65% (group B). No significant differences were found among the two groups regarding the 30-day complication rate (86% in group A versus 73% in group B, p = 0.82) and LOS (14 days in group A versus 15 days in group B, p = 0.82). The time to stool was significantly shorter in group B (4 days versus 6 days, p = 0.02), and the time to tolerate solid food was slightly faster in group B but not significant (8 versus 7 days, p = 0.23). The POI rate was significantly lower in patients with a higher ERAS &lt;sup&gt;®&lt;/sup&gt; compliance (20% versus 46%, p = 0.01). A multivariate analysis showed that ERAS &lt;sup&gt;®&lt;/sup&gt; compliance was not significantly associated with 30-day total complications. However, a lower compliance to the ERAS &lt;sup&gt;®&lt;/sup&gt; protocol and age &gt; 75 years were significant independent predictors of POI. Our study provides further evidence to support the beneficial effect of the ERAS &lt;sup&gt;®&lt;/sup&gt; protocol in patients undergoing RC, particularly in terms of facilitating a faster recovery of bowel function and preventing POI. Future research should focus on investigating novel approaches and interventions to improve compliance with the ERAS &lt;sup&gt;®&lt;/sup&gt; protocol. This may involve patient education, multidisciplinary teamwork, and continuous quality improvement initiatives

    Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in sqrt{s} = 7 TeV pp collisions using 1 fb-1 of ATLAS data

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    We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb^-1 of proton-proton collision data at sqrt{s} = 7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross-section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross-sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation.Comment: 18 pages plus author list (30 pages total), 9 figures, 4 tables, final version to appear in Physical Review
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