962 research outputs found

    Association between GH encoding gene polymorphism and semen characteristics in Iranian Holstein bulls

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    The objective of this present study was to investigate relationships between the growth hormone gene restriction fragment length  polymorphism (RFLP) and bull sperm characteristics. A total of 89 bullsfrom two semen evaluation stations were genotyped for the bovine growth hormone (bGH)-AluI polymorphism by polymerase chain reaction and followed by 4% metaphor agaros gel electrophoresis. The overall allele frequencies for two L and V alleles were 0.50, respectively. The relationship between the bGH-AluI polymorphism and semen characteristics was evaluated according 1500 ejaculated records. Five sperm characteristics were analyzed. Sperm characteristics showed significant variabilityin relation to bGH genotypes. LL bulls had a lower ejaculated volume and higher percentage of live sperm, and VV bulls had higher fresh sperm concentration and minimum effect after cryopreservation. This polymorphism could be further used for semen evaluation process in artificial insemination program in Iranian Holstein bulls.Key word: Semen characteristics, growth hormone (GH) polymorphism, Holstein bulls

    Correlation of reconstructed scaphoid morphology with clinical outcomes

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    Background: Scaphoid malunion alters the carpal kinematics and impairs clinical outcome because of pain, weakness, restricted range of motion and predisposing the wrist joint to early osteoarthritis. The aim of this study was to evaluate the influence of the scaphoid morphological angles on clinical outcomes in patients with reconstructed scaphoid by non-vascularized bone graft. Methods: Seventeen male patients with the mean age of 31.7±3.7 years and mean non-union time of 31.5±14.7 months were enrolled in this retrospective study. Average follow up was 48.8±9.4 months. At the last follow-up, the patients were evaluated clinically for pain, wrist range of motion, grip strength, and wrist functional status. They were also evaluated radiologically by wrist radiographs and computerized tomography (CT). The overall clinical outcomes were evaluated by the Cooney wrist function score. The morphology of the reconstructed scaphoids was evaluated by the lateral intrascaphoid angle, antroposterior intrascaphoid angle, dorsal cortical angle, measuring the length (mm), and height-to-length ratio on CT scan. The radiological measurements were compared against the overall clinical outcomes. Results: There were 7 excellent, 7 good, 3 fair clinical results. The mean Cooney wrist function score was 83±4. The mean lateral intrascaphoid angle was 34.8±1.4 degrees, mean antroposterior intrascaphoid angle was 33.4±2.2 degrees, mean dorsal cortical angle was 158.3±4.8 degrees, mean scaphoid length was 22.1± 0.7 mm, and mean scaphoid height-to-length ratio was 0.74±0.04. There were no significant statistical correlations between the lateral intrascaphoid angles, antroposterior intrascaphoid angles, dorsal cortical angles, scaphoid lengths and scaphoid height-to-length ratios and Cooney wrist scores in the patients. Conclusion: In the current study, all the patients had some degree of scaphoid malunion; however, the radiological measurements of the reconstructed scaphoids did not correlate with the clinical outcomes. © 2015 BY THE ARCHIVES OF BONE AND JOINT SURGERY

    Interacting spin-2 fields in three dimensions

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    Using the frame formulation of multi-gravity in three dimensions, we show that demanding the presence of secondary constraints which remove the Boulware-Deser ghosts restricts the possible interaction terms of the theory and identifies invertible frame field combinations whose effective metric may consistently couple to matter. The resulting ghost-free theories can be represented by theory graphs which are trees. In the case of three frame fields, we explicitly show that the requirement of positive masses and energies for the bulk spin-2 modes in AdS3_3 is consistent with a positive central charge for the putative dual CFT2_2.Comment: 26 pages, 3 figures, v2: minor changes, matches published versio

    Anisotropy of the Seebeck Coefficient in the Cuprate Superconductor YBa2_{2}Cu3_{3}Oy_{y}: Fermi-Surface Reconstruction by Bidirectional Charge Order

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    The Seebeck coefficient SS of the cuprate YBa2_{2}Cu3_{3}Oy_{y} was measured in magnetic fields large enough to suppress superconductivity, at hole dopings p=0.11p = 0.11 and p=0.12p = 0.12, for heat currents along the aa and bb directions of the orthorhombic crystal structure. For both directions, S/TS/T decreases and becomes negative at low temperature, a signature that the Fermi surface undergoes a reconstruction due to broken translational symmetry. Above a clear threshold field, a strong new feature appears in SbS_{\rm b}, for conduction along the bb axis only. We attribute this feature to the onset of 3D-coherent unidirectional charge-density-wave modulations seen by x-ray diffraction, also along the bb axis only. Because these modulations have a sharp onset temperature well below the temperature where S/TS/T starts to drop towards negative values, we infer that they are not the cause of Fermi-surface reconstruction. Instead, the reconstruction must be caused by the quasi-2D bidirectional modulations that develop at significantly higher temperature.Comment: 7 pages, 5 figure

    Fermi-surface transformation across the pseudogap critical point of the cuprate superconductor La1.6x_{1.6-x}Nd0.4_{0.4}Srx_{x}CuO4_4

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    The electrical resistivity ρ\rho and Hall coefficient RH_H of the tetragonal single-layer cuprate Nd-LSCO were measured in magnetic fields up to H=37.5H = 37.5 T, large enough to access the normal state at T0T \to 0, for closely spaced dopings pp across the pseudogap critical point at p=0.235p^\star = 0.235. Below pp^\star, both coefficients exhibit an upturn at low temperature, which gets more pronounced with decreasing pp. Taken together, these upturns show that the normal-state carrier density nn at T=0T = 0 drops upon entering the pseudogap phase. Quantitatively, it goes from n=1+pn = 1 + p at p=0.24p = 0.24 to n=pn = p at p=0.20p = 0.20. By contrast, the mobility does not change appreciably, as revealed by the magneto-resistance. The transition has a width in doping and some internal structure, whereby RH_H responds more slowly than ρ\rho to the opening of the pseudogap. We attribute this difference to a Fermi surface that supports both hole-like and electron-like carriers in the interval 0.2<p<p0.2 < p < p^\star, with compensating contributions to RH_H. Our data are in excellent agreement with recent high-field data on YBCO and LSCO. The quantitative consistency across three different cuprates shows that a drop in carrier density from 1+p1 + p to pp is a universal signature of the pseudogap transition at T=0T=0. We discuss the implication of these findings for the nature of the pseudogap phase.Comment: 11 pages, 12 figure

    Spread of efflux pump overexpressing-mediated fluoroquinolone resistance and multidrug resistance in Pseudomonas aeruginosa by using an efflux pump inhibitor

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    Background: Fluoroquinolone resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression and/or target mutations. We designed this study to investigate the efflux pump mediated fluoroquinolone resistance and check the increasing effectiveness of fluoroquinolones in combination with an efflux pumps inhibitor among P. aeruginosa isolates from burn wounds infections. Materials and Methods: A total of 154 consecutive strains of P. aeruginosa were recovered from separate patients hospitalized in a burn hospital, Tehran, Iran. The isolates first were studied by disk diffusion antibiogram for 11 antibiotics and then minimum inhibitory concentration (MIC) experiments were performed to detect synergy between ciprofloxacin and the efflux pump inhibitor, carbonyl cyanide-m-chlorophenyl hydrazone (CCCP). Then to elucidate the inducing of multi drug resistance due to different efflux pumps activation in Fluoroquinolone resistant isolates, synergy experiments were also performed in random ciprofloxacin resistant isolates which have overexpressed efflux pumps phenotypically, using CCCP and selected antibiotics as markers for Beta-lactams and Aminoglycosides. The isolates were also tested by polymerase chain reaction (PCR) for the presence of the MexA, MexC and MexE, which encode the efflux pumps MexAB-OprM, MexCD-OprJ and MexEF-OprN. Results: Most of the isolates were resistant to 3 or more antibiotics tested. More than half of the ciprofloxacin resistant isolates exhibited synergy between ciprofloxacin and CCCP, indicating the efflux pump activity contributed to the ciprofloxacin resistance. Also increased susceptibility of random ciprofloxacin resistant isolates of P. aeruginosa to other selected antibiotics, in presence of CCCP, implied multidrug extrusion by different active efflux pump in fluoroquinolones resistant strains. All of Ciprofloxacin resistant isolates were positive for MexA, MexC and MexE genes simultaneously. Conclusion: In this burn hospital, where multidrug resistant P. aeruginosa isolates were prevalent, ciprofloxacin resistance and multidrug resistance due to the overexpression of fluoroquinolones mediated efflux pumps has also now emerged. Early recognition of this resistance mechanism should allow the use of alternative antibiotics and use an efflux pumps inhibitor in combination with antibiotic therapy. © 2015 by The Korean Society of Infectious Diseases

    Microdust impact on leaf gas exchange parameters in oak species of Northern Zagros forests, west of Iran

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    In recent years, the microdust phenomenon has greatly changed in concentration, duration and continuity as well as the frequency of occurrence in comparison with dust storms in the past which has caused a great deal of concern. Microdust is one of the most devastating factors in the environment threatening all animal and plant species. Regarding to the microdust impending threat, its ecological and economic impacts on scarce species is critical. Zagros forests act as an intrinsic filter for microdust in the western region of Iran. This study investigates the effect of microdust on oak, the most important tree in the Zagros forests. So that, three-year old seedlings of three oak species (Quercus branti, Q. libni and Q. infectoria) were exposed to microdust under natural conditions during spring and summer 2016. We examined the rate of photosynthesis, stomatal conductance, transpiration, internal CO2, mesophyll conductance, water use efficiency in control and treated plants. The results indicated that microdust had a significant impact on the examined parameters of the three oak species (P≤0.01). The gas exchange and photosynthetic rates of the treated plants were significantly reduced. In Q. infectoria, microdust had the greatest impact on photosynthesis, stomatal conductance, leaf internal CO2, transpiration and mesophyll conductance. Accordingly, microdust had a substantial influence on photosynthesis and mesophyll conductance in Q. brantii as well as the leaf internal CO2 and mesophyll conductance in Q. libani. Therefore, based on these findings, it can be concluded that microdust can disrupt the physiological activities of the examined species. Hence, continuous - exposure to microdust will accelerate the process of destruction of these forests

    The GRA Beam-Splitter Experiments and Particle-Wave Duality of Light

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    Grangier, Roger and Aspect (GRA) performed a beam-splitter experiment to demonstrate the particle behaviour of light and a Mach-Zehnder interferometer experiment to demonstrate the wave behaviour of light. The distinguishing feature of these experiments is the use of a gating system to produce near ideal single photon states. With the demonstration of both wave and particle behaviour (in two mutually exclusive experiments) they claim to have demonstrated the dual particle-wave behaviour of light and hence to have confirmed Bohr's principle of complementarity. The demonstration of the wave behaviour of light is not in dispute. But we want to demonstrate, contrary to the claims of GRA, that their beam-splitter experiment does not conclusively confirm the particle behaviour of light, and hence does not confirm particle-wave duality, nor, more generally, does it confirm complementarity. Our demonstration consists of providing a detailed model based on the Causal Interpretation of Quantum Fields (CIEM), which does not involve the particle concept, of GRA's which-path experiment. We will also give a brief outline of a CIEM model for the second, interference, GRA experiment.Comment: 24 pages, 4 figure

    Covariant coarse-graining of inhomogeneous dust flow in General Relativity

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    A new definition of coarse-grained quantities describing the dust flow in General Relativity is proposed. It assigns the coarse--grained expansion, shear and vorticity to finite-size comoving domains of fluid in a covariant, coordinate-independent manner. The coarse--grained quantities are all quasi-local functionals, depending only on the geometry of the boundary of the considered domain. They can be thought of as relativistic generalizations of simple volume averages of local quantities in a flat space. The procedure is based on the isometric embedding theorem for S^2 surfaces and thus requires the boundary of the domain in question to have spherical topology and positive scalar curvature. We prove that in the limit of infinitesimally small volume the proposed quantities reproduce the local expansion, shear and vorticity. In case of irrotational flow we derive the time evolution for the coarse-grained quantities and show that its structure is very similar to the evolution equation for their local counterparts. Additional terms appearing in it may serve as a measure of the backreacton of small-scale inhomogeneities of the flow on the large-scale motion of the fluid inside the domain and therefore the result may be interesting in the context of the cosmological backreaction problem. We also consider the application of the proposed coarse-graining procedure to a number of known exact solutions of Einstein equations with dust and show that it yields reasonable results.Comment: 17 pages, 5 figures. Version accepted in Classical and Quantum Gravity
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