804 research outputs found

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

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    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(B−V)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/dM∝M−(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 (τ≄1\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

    IFT88 transports Gucy2d, a guanylyl cyclase, to maintain sensory cilia function in Drosophila

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    Cilia are involved in a plethora of motility and sensory-related functions. Ciliary defects cause several ciliopathies, some of which with late-onset, suggesting cilia are actively maintained. While much is known about cilia assembly, little is understood about the mechanisms of their maintenance. Given that intraflagellar transport (IFT) is essential for cilium assembly, we investigated the role of one of its main players, IFT88, in ciliary maintenance. We show that DmIFT88, the Drosophila melanogaster orthologue of IFT88, continues to move along fully formed sensory cilia, and that its acute knockdown in the ciliated neurons of the adult affects sensory behaviour. We further identify DmGucy2d, the Drosophila guanylyl cyclase 2d, as a DmIFT88 cargo, whose loss also leads to defects in sensory behaviour maintenance. DmIFT88 binds to the intracellular part of DmGucy2d, a highly, evolutionarily conserved and mutated in several degenerative retina diseases, taking the cyclase into the cilia. Our results offer a novel mechanism for the maintenance of sensory cilia function and its potential role in human diseases

    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 Zâ€ČZ' 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−) 10−2Br(Z_2 --> l^+l^-) ~ 10^{-2} and Br(Z2−−>ΜˉlÎœ) 10−3Br(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−−>Z1ÎłZ_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−−>Z1Îł) 10−9Br(Z_2 --> Z_1\gamma) ~ 10^{-9} and Br(Z2−−>Z1Z1) 10−6Br(Z_2 --> Z_1Z_1) ~ 10^{-6} at most. As for the Z2−−>W+W−Z_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−) 10−2Br(Z_2 --> W^+W^-) ~ 10^{-2} and Br(Z2−−>Z1H) 10−5Br (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 10−310^{-3} and 10−510^{-5}, respectively, and thus may be of phenomenological interest.Comment: 14 pages, 3 figures, submitted to Physical Review

    Double Positive CD4<sup>+</sup>CD8<sup>+</sup> T Cells Are Enriched in Urological Cancers and Favor T Helper-2 Polarization.

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    The immune system plays a central role in cancer development, showing both anti-tumor and pro-tumor activities depending on the immune cell subsets and the disease context. While CD8 T cells are associated with a favorable outcome in most cancers, only T helper type 1 (Th1) CD4 T cells play a protective role, in contrast to Th2 CD4 T cells. Double positive (DP) CD4 &lt;sup&gt;+&lt;/sup&gt; CD8 &lt;sup&gt;+&lt;/sup&gt; T cells remain understudied, although they were already described in human cancers, with conflicting data regarding their role. Here, we quantified and phenotypically/functionally characterized DP T cells in blood from urological cancer patients. We analyzed blood leukocytes of 24 healthy donors (HD) and 114 patients with urological cancers, including bladder (n = 54), prostate (n = 31), and kidney (n = 29) cancer patients using 10-color flow cytometry. As compared to HD, levels of circulating DP T cells were elevated in all urological cancer patients, which could be attributed to increased frequencies of both CD4 &lt;sup&gt;high&lt;/sup&gt; CD8 &lt;sup&gt;low&lt;/sup&gt; and CD4 &lt;sup&gt;+&lt;/sup&gt; CD8 &lt;sup&gt;high&lt;/sup&gt; DP T-cell subsets. Of note, most CD4 &lt;sup&gt;high&lt;/sup&gt; CD8 &lt;sup&gt;low&lt;/sup&gt; DP T cells show a CD8αα phenotype, whereas CD4 &lt;sup&gt;+&lt;/sup&gt; CD8 &lt;sup&gt;high&lt;/sup&gt; cells express both CD8α and CD8ÎČ subunits. Functional properties were investigated using ex-vivo generated DP T-cell clones. DP T cells from patients were skewed toward an effector memory phenotype, along with enhanced Th2 cytokine production. Interestingly, both CD8αα and CD8αÎČ DP T cells were able to trigger Th2 polarization of naĂŻve CD4 T cells, while restraining Th1 induction. Thus, these data highlight a previously unrecognized immunoregulatory mechanism involving DP CD4 &lt;sup&gt;+&lt;/sup&gt; CD8 &lt;sup&gt;+&lt;/sup&gt; T cells in urological cancers
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