1,226 research outputs found

    Characterisation of Goats’ Response to Heat Stress: Tools to Improve Heat Tolerance

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    This chapter aims to review present knowledge about the effects of heat stress on goats, summarising what is known about its measurement, its impact on the performances of the animals, mainly milk traits, the physiological and genetic bases of the animals’ response and the improvement of resilience through selection. A short historic review of the climatic indexes used to measure heat stress, with special emphasis on the temperature humidity indexes, and the main consequences on milk yield and composition are followed by a description of the results of experiments carried out to study the physiological and metabolic consequences of heat stress. The results of the quantitative analyses of the genetic bases of heat stress using norm of reaction models and of the application of omic techniques, particularly transcriptomic and genomic, to understand the complexity of the genetic background of animal’s reaction to thermal stress, constitute the next points. The chapter ends treating the possible ways and difficulties of applying selection to increase resilience to heat stress

    Short communication: An association analysis between one missense polymorphism at the SREBF1 gene and milk yield and composition traits in goats

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    Sterol regulatory element binding transcription factor 1 (SREBF1) regulates the expression of genes involved in the biosynthesis of fatty acids and cholesterol. Herewith, we have sequenced the near-complete coding region and part of the 3?UTR of the goat SREBF1 gene. In doing so, we have detected a missense c.353CT polymorphism causing a proline to leucine substitution at position 118 (P118L). An association analysis with milk composition traits recorded in MurcianoGranadina goats only revealed a statistical tendency linking SREBF1 genotype and milk omega-3 fatty acid content. The lack of significant associations suggests that the P118L substitution does not involve a functional change.Le facteur de transcription de´nomme´ Sterol regulatory element binding transcription factor 1 (SREBF1) re´gule l’expression des ge`nes implique´s dans la biosynthe`se des acides gras et du choleste´rol. Dans cette e´tude, nous avons se´quence´ la quasi-totalite´ de la re´gion codante et une partie du la re´gion 3?UTR du ge`ne SREBF1 de la che`vre. Ce travail, nous a permis d’identifier un polymorphisme non-synonyme c.353CT causant la substitution d’une Proline en Leucine a` la position 118. L’e´tude d’association avec la composition du lait enregistre´e en che`vres Murciano-Granadina, a re´ve´le´ seulement une tendance statistique reliant SREBF1 ge´notype et l’acide gras ome´ga-3 du lait. L’absence d’associations significatives sugge`re que la substitution P118L n’implique pas un changement fonctionnel

    EFFECT OF SALINITY ON THE DIELECTRIC PROPERTIES OF GEOLOGICAL MATERIALS : IMPLICATION FOR SOIL MOISTURE DETECTION BY MEANS OF REMOTE SENSING

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    International audienceThis paper deals with the exploitation of dielectric properties of saline deposits for the detection and mapping of moisture in arid regions on both Earth and Mars. We then present a simulation and experimental study in order to assess the effect of salinity on the permittivity of geological materials and therefore on the radar backscattering coefficient in the [1-7GHz] frequency range. Dielectric mixing models were first calibrated by means of experimental measurements before being used as input parameters of analytical scattering models (IEM, SPM). Simulation results will finally be compared to field measurements (Pyla dune, Death Valley, Mojave Desert) and will be used for the interpretation of SAR data (AIRSAR, PALSAR)

    Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

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    Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 <pT,assoc<pT,trig< < p_{\rm{T}, assoc} < p_{\rm{T}, trig} < 5.0 GeV/cc is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range η<0.9|\eta|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

    Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

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    Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a Δη|\Delta \eta| gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of v2{4}v_{2}\{4\} to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find v2{4}v2{6}0v_{2}\{4\} \simeq v_{2}\{6\}\neq 0 which is indicative of a Bessel-Gaussian function for the v2v_{2} distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a Δη>1.4|\Delta\eta| > 1.4 gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

    Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

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    Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range η<0.8|\eta| < 0.8 are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286

    A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE

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    In this small note we are concerned with the solution of Forward-Backward Stochastic Differential Equations (FBSDE) with drivers that grow quadratically in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem is a comparison result that allows comparing componentwise the signs of the control processes of two different qgFBSDE. As a byproduct one obtains conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio

    Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at s=0.9\sqrt{s}=0.9, 2.76 and 7 TeV

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    Measurements of the sphericity of primary charged particles in minimum bias proton--proton collisions at s=0.9\sqrt{s}=0.9, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable is linearized to be collinear safe and is measured in the plane perpendicular to the beam direction using primary charged tracks with pT0.5p_{\rm T}\geq0.5 GeV/c in η0.8|\eta|\leq0.8. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity (NchN_{\rm ch}) is reported for events with different pTp_{\rm T} scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low NchN_{\rm ch}, whereas the event generators show the opposite tendency. The combined study of the sphericity and the mean pTp_{\rm T} with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data, compared to the other tested generators.Comment: 21 pages, 9 captioned figures, 3 tables, authors from page 16, published version, figures from http://aliceinfo.cern.ch/ArtSubmission/node/308
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