53,885 research outputs found

    Antimicrobial susceptibility assessment of Campylobacter on outdoor iberian pig sows

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    Both Campylobacter and Salmonella are considered the most frequent bacterial causes of human enteritis in industrialized countries. The consumption of raw or undercooked poultry and pork contaminated meat products are the main sources of human infection. The prevalence of Campylobacter and Salmonella was determined in the present work for extensive production Iberian pig sows, Sus mediterraneus. Samples were collected at the maternity area of a creator from, water drinkers, feed and feed containers as well as from sows faecal matter. Of 42 samples, 31 and 23 carried Campylobacter spp. and Salmonella spp. respectively. Only Salmonella spp. was found in all 3 tested water and feed containers. Of the 58 isolated Campylobacter strains only one was identified, by multiplex-PCR, as Campylobacter jejuni, all other were C. coli. Antibiotic susceptibility was performed by disc diffusion method with Nalidixic acid, Ciprofloxacin, Erythromycin, Tetracycline, Chloramphenicol and Ampicilin. While 95% of the tested strains were susceptible to chloramphenicol, 66% and 53% were resistant to the tested fluoroquinolones, Ciprofloxacin and Nalidixic acid respectively. Erythromycin resistance was fairly low in comparison to previous publications with 14% of resistant strains. 38% were resistant to Tetracycline and 57% to Ampicilin. Seven of the 58 Campylobacter strains were entirely susceptible and none were resistant to all the antimicrobials tested. Multiple drug resistance was found in 88% of strains. Cross contamination may occur between sows inside maternity facilities and piglets may become infected in an early age by their mothers. New and better control measures are therefore necessary to minimize transmission between animals reducing the number of contaminated individuals and the potential transmission to human handlers and consumers

    Axion Electrodynamics from Infeld-van der Waerden formalisms

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    In this article we will explore the spacetime phase structure inside the Infeld-van der Waerden formalisms, showing that Maxwell's theory in this scenario leads to an axion-like phase electrodynamics, which suggests that this phase may originate the axion field.Comment: 15 page

    Transfer of optical spectral weight in magnetically ordered superconductors

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    We show that, in antiferromagnetic superconductors, the optical spectral weight transferred to low frequencies below the superconducting transition temperature originates from energies that can be much larger than twice the superconducting gap Δ\Delta. This contrasts to non-magnetic superconductors, where the optical spectrum is suppressed only for frequencies below 2Δ2\Delta. In particular, we demonstrate that the superfluid condensate of the magnetically ordered superconductor is not only due to states of the magnetically reconstructed Fermi surface, but is enhanced by transfer of spectral weight from the mid infrared peak generated by the spin density wave gap. We apply our results to the iron arsenide superconductors, addressing the decrease of the zero-temperature superfluid density in the doping regime where magnetism coexists with unconventional superconductivity.Comment: 5 figures, 10 pages; revised versio

    Extended quantum portrait of MGD black holes and information entropy

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    The extended minimal geometric deformation (EMGD) is employed on the fluid membrane paradigm, to describe compact stellar objects as Bose--Einstein condensates (BEC) consisting of gravitons. The black hole quantum portrait, besides deriving a preciser phenomenological bound for the fluid brane tension, is then scrutinized from the point of view of the configurational entropy. It yields a range for the critical density of the EMGD BEC, whose configurational entropy has global minima suggesting the configurational stability of the EMGD BEC.Comment: 9 pages, 7 figures, matches the published versio

    Numerical solution of open string field theory in Schnabl gauge

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    Using traditional Virasoro L0L_0 level-truncation computations, we evaluate the open bosonic string field theory action up to level (10,30)(10,30). Extremizing this level-truncated potential, we construct a numerical solution for tachyon condensation in Schnabl gauge. We find that the energy associated to the numerical solution overshoots the expected value 1-1 at level L=6L=6. Extrapolating the level-truncation data for L10L\leq 10 to estimate the vacuum energies for L>10L > 10, we predict that the energy reaches a minimum value at L12L \sim 12, and then turns back to approach 1-1 asymptotically as LL \rightarrow \infty. Furthermore, we analyze the tachyon vacuum expectation value (vev), for which by extrapolating its corresponding level-truncation data, we predict that the tachyon vev reaches a minimum value at L26L \sim 26, and then turns back to approach the expected analytical result as LL \rightarrow \infty.Comment: 37 pages, 9 figures, some typos correcte

    Gap nodes induced by coexistence with antiferromagnetism in iron-based superconductors

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    We investigate the pairing in iron pnictides in the coexistence phase, which displays both superconducting and antiferromagnetic orders. By solving the pairing problem on the Fermi surface reconstructed by long-range magnetic order, we find that the pairing interaction necessarily becomes angle-dependent, even if it was isotropic in the paramagnetic phase, which results in an angular variation of the superconducting gap along the Fermi surfaces. We find that the gap has no nodes for a small antiferromagnetic order parameter M, but may develop accidental nodes for intermediate values of M, when one pair of the reconstructed Fermi surface pockets disappear. For even larger M, when the other pair of reconstructed Fermi pockets is gapped by long-range magnetic order, superconductivity still exists, but the quasiparticle spectrum becomes nodeless again. We also show that the application of an external magnetic field facilitates the formation of nodes. We argue that this mechanism for a nodeless-nodal-nodeless transition explains recent thermal conductivity measurements of hole-doped Ba_{1-x}K_xFe_2As_2. [J-Ph. Read et.al. arXiv:1105.2232].Comment: 13 pages, 10 figures, submitted to PR

    Optical and Near Infrared Study of the Cepheus E outflow, a very low excitation object

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    We present images and spectra of the Cepheus E (Cep E) region at both optical and infrared wavelengths. Only the brightest region of the southern lobe of the Cep E outflow reveals optical emission, suggesting that the extinction close to the outflow source plays an important r\^ole in the observed difference between the optical and IR morphologies. Cep E is a unique object since it provides a link between the spectroscopic properties of the optical Herbig-Haro (HH) objects and those of deeply embedded outflows.Comment: Accepted Astron. J., 8 files: paper, tables plus 6 figure
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