5,345 research outputs found

    Effects of equine chrionic gonadotrophin (eCG) on corpus luteum development and progesterone concentrations in Nelore cows.

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    This trial aimed to test eCG as an enhancer of the luteal function, as well as to evaluate the ability of eCG to delay or prevent luteolysis mechanism. A group of 32 mature, synchronized (CRESTAR@), lactating Nelore (Bos taurus indicus) cows were randomly allotted to receive either 400 lU of eCG at implant withdrawal (GeCG; n=16) or remain as contrais (GC; n=16). Ultrasound per rectum evaluation of avaries was conducted daily, from implant rem oval up to the following ovulation (a complete estrous cycle). Simultaneously, blood samples were taken to determine plasmatic concentration of progesterone ([P4]). Data were analyzed by GLM of the SAS program. GeCG showed non-significant (P>.05) higher volume of corpus luteum (CL) from day 3 after synchronized ovulation up to lhe rest of lhe luteal phase. In addition, eCG promoted a longer lasting growing period of lhe CL without changing its growing rale (P>.05) as compared to GC. As a result, CI maximum volume was reached later (9.2:t .47 days) and achieved a larger dimension (6927.5:t 405.86 mm3) for GeCG than occurred for GC (respectively, 7.7:t .47 days and 5437.8:t 405.86 mm3). The peak of [P4] was observed at lhe same time for both groups (11.3 t .59 and 11.4 t .59 days for GeCG and GC, respectively). However, maximum [P4] was higher (P.O5) for both groups (17.3 t .45 to GeCG and 17.1 t .45 days of lhe estrous cycle to GC). As a consequence, estrous cycle length did not differ (P>.O5) between treated (21.8 t .57 days) and non-treated cows (21.4 t .57 days). In summary, eCG not only increased CL dimension but also optimized [P4] over the luteal phase ofthe estrous cycle. Therefore, eCG given at implant removal provided a luteotrophic effect, but it was not capable to delay luteolysis

    Large scale structure simulations of inhomogeneous LTB void models

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    We perform numerical simulations of large scale structure evolution in an inhomogeneous Lemaitre-Tolman-Bondi (LTB) model of the Universe. We follow the gravitational collapse of a large underdense region (a void) in an otherwise flat matter-dominated Einstein-deSitter model. We observe how the (background) density contrast at the centre of the void grows to be of order one, and show that the density and velocity profiles follow the exact non-linear LTB solution to the full Einstein equations for all but the most extreme voids. This result seems to contradict previous claims that fully relativistic codes are needed to properly handle the non-linear evolution of large scale structures, and that local Newtonian dynamics with an explicit expansion term is not adequate. We also find that the (local) matter density contrast grows with the scale factor in a way analogous to that of an open universe with a value of the matter density OmegaM(r) corresponding to the appropriate location within the void.Comment: 7 pages, 6 figures, published in Physical Review

    Positive maps, majorization, entropic inequalities, and detection of entanglement

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    In this paper, we discuss some general connections between the notions of positive map, weak majorization and entropic inequalities in the context of detection of entanglement among bipartite quantum systems. First, basing on the fact that any positive map Λ:Md(C)Md(C)\Lambda:M_{d}(\mathbb{C})\to M_{d}(\mathbb{C}) can be written as the difference between two completely positive maps Λ=Λ1Λ2\Lambda=\Lambda_{1}-\Lambda_{2}, we propose a possible way to generalize the Nielsen--Kempe majorization criterion. Then we present two methods of derivation of some general classes of entropic inequalities useful for the detection of entanglement. While the first one follows from the aforementioned generalized majorization relation and the concept of the Schur--concave decreasing functions, the second is based on some functional inequalities. What is important is that, contrary to the Nielsen--Kempe majorization criterion and entropic inequalities, our criteria allow for the detection of entangled states with positive partial transposition when using indecomposable positive maps. We also point out that if a state with at least one maximally mixed subsystem is detected by some necessary criterion based on the positive map Λ\Lambda, then there exist entropic inequalities derived from Λ\Lambda (by both procedures) that also detect this state. In this sense, they are equivalent to the necessary criterion [I\ot\Lambda](\varrho_{AB})\geq 0. Moreover, our inequalities provide a way of constructing multi--copy entanglement witnesses and therefore are promising from the experimental point of view. Finally, we discuss some of the derived inequalities in the context of recently introduced protocol of state merging and possibility of approximating the mean value of a linear entanglement witness.Comment: the published version, 25 pages in NJP format, 6 figure

    Spectral Properties of the Core and the VLBI-Jets of Cygnus A

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    We present a detailed VLBI study of the spectral properties of the inner core region of the radio galaxy Cygnus A at 5 GHz, 15 GHz, 22 GHz, 43 GHz and 86 GHz. Our observations include an epoch using phase-referencing at 15 GHz and 22 GHz and the first successful VLBI observations of Cygnus A at 86 GHz. We find a pronounced two-sided jet structure, with a steep spectrum along the jet and an inverted spectrum towards the counter-jet. The inverted spectrum and the frequency-dependent jet-to-counter-jet ratio suggest that the inner counter-jet is covered by a circum-nuclear absorber as it is proposed by the unified scheme.Comment: 2 pages, 2 figures, Proceedings of the 7th EVN Symposium held in Toledo, Spain in October 2004, needs evn2004.cl

    The combination of trichoderma harzianum and chemical fertilization leads to the deregulation of phytohormone networking, preventing the adaptive responses of tomato plants to salt stress.

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    Abstract: Plants have evolved effective mechanisms to avoid or reduce the potential damage caused by abiotic stresses. In addition to biocontrol abilities, Trichoderma genus fungi promote growth and alleviate the adverse effects caused by saline stress in plants. Morphological, physiological, and molecular changes were analyzed in salt-stressed tomato plants grown under greenhouse conditions in order to investigate the effects of chemical and biological fertilizations. The application of Trichoderma harzianum T34 to tomato seeds had very positive effects on plant growth, independently of chemical fertilization. The application of salt stress significantly changed the parameters related to growth and gas-exchange rates in tomato plants subject to chemical fertilization. However, the gas-exchange parameters were not affected in unfertilized plants under the same moderate saline stress. The combined application of T34 and salt significantly reduced the fresh and dry weights of NPK-fertilized plants, while the opposite effects were detected when no chemical fertilization was applied. Decaying symptoms were observed in salt-stressed and chemically fertilized plants previously treated with T34. This damaged phenotype was linked to significantly higher intercellular CO2 and slight increases in stomatal conductance and transpiration, and to the deregulation of phytohormone networking in terms of significantly lower expression levels of the salt overlay sensitivity 1 (SOS1) gene, and the genes involved in signaling abscisic acid-, ethylene-, and salicylic acid-dependent pathways and ROS production, in comparison with those observed in salt-challenged NPK-fertilized plants

    [OI] disk emission in the Taurus star forming region

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    The structure of protoplanetary disks is thought to be linked to the temperature and chemistry of their dust and gas. Whether the disk is flat or flaring depends on the amount of radiation that it absorbs at a given radius, and on the efficiency with which this is converted into thermal energy. The understanding of these heating and cooling processes is crucial to provide a reliable disk structure for the interpretation of dust continuum emission and gas line fluxes. Especially in the upper layers of the disk, where gas and dust are thermally decoupled, the infrared line emission is strictly related to the gas heating/cooling processes. We aim to study the thermal properties of the disk in the oxygen line emission region, and to investigate the relative importance of X-ray (1-120 Angstrom) and far-UV radiation (FUV, 912-2070 Angstrom) for the heating balance there. We use [OI] 63 micron line fluxes observed in a sample of protoplanetary disks of the Taurus/Auriga star forming region and compare it to the model predictions presented in our previous work. The data were obtained with the PACS instrument on board the Herschel Space Observatory as part of the Herschel Open Time Key Program GASPS (GAS in Protoplanetary diskS), published in Howard et al. (2013). Our theoretical grid of disk models can reproduce the [OI] absolute fluxes and predict a correlation between [OI] and the sum Lx+Lfuv. The data show no correlation between the [OI] line flux and the X-ray luminosity, the FUV luminosity or their sum. The data show that the FUV or X-ray radiation has no notable impact on the region where the [OI] line is formed. This is in contrast with what is predicted from our models. Possible explanations are that the disks in Taurus are less flaring than the hydrostatic models predict, and/or that other disk structure aspects that were left unchanged in our models are important. ..abridged..Comment: 9 pages, accepted for publication in A&
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