673 research outputs found

    Prevalence and clinical signs of postpartum dysgalactia syndrome at the first day after farrowing in farmed sows in the Republic of Macedonia

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    The objective of the present study was to determine the prevalence of postpartum dysgalactia syndrome (PDS) and associated clinical signs in farmed sows in the Republic of Macedonia (RM) in the first 12-24 h postpartum. A total of 202 sows of different parity and different genetic lines from 5 pig farms in RM were included in the study. The sows and their litters were clinically examined 12-24 hours after farrowing. Postpartum dysgalactia syndrome was detected in 23.3% of all clinically examined sows, while prevalence between farms ranged from 14.8% to 38.1%. Altered piglet’s behavior was the most frequent clinical pattern observed in 68.1% of the PDS–affected (PDSA) sows. Regarding the clinical signs in PDSA sows detected among farms, significant differences were observed in the altered piglet’s behavior (p lt 0.05) and hypogalactia (p lt 0.05). Endometritis was more often detected in older sows (90%) compared to endometritis in younger animals (44.4%). In addition, fever was also more frequently diagnosed in higher parity (≥3 parity) sows (55.0%) in contrast to other PDSA sows (22.2%). This study has demonstrated the presence of PDS in farmed sows in RM. High frequency of altered piglet’s behavior found in this study could be an useful indicator for early detection of lactation problems in sows. Frequent pathological vaginal discharge in older sows indicates that endometritis plays an important role in the clinical manifestation of PDS. Further investigations should be conducted in order to identify specific risk factors associated with clinical PDS in farmed sows in RM

    Statistics of Heat Transfer in Mesoscopic Circuits

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    A method to calculate the statistics of energy exchange between quantum systems is presented. The generating function of this statistics is expressed through a Keldysh path integral. The method is first applied to the problem of heat dissipation from a biased mesoscopic conductor into the adjacent reservoirs. We then consider energy dissipation in an electrical circuit around a mesoscopic conductor. We derive the conditions under which measurements of the fluctuations of heat dissipation can be used to investigate higher order cumulants of the charge counting statistics of a mesoscopic conductor.Comment: 9 pages, 6 figure

    Interaction effects on magnetooscillations in a two-dimensional electron gas

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    Motivated by recent experiments, we study the interaction corrections to the damping of magnetooscillations in a two-dimensional electron gas (2DEG). We identify leading contributions to the interaction-induced damping which are induced by corrections to the effective mass and quantum scattering time. The damping factor is calculated for Coulomb and short-range interaction in the whole range of temperatures, from the ballistic to the diffusive regime. It is shown that the dominant effect is that of the renormalization of the effective electron mass due to the interplay of the interaction and impurity scattering. The results are relevant to the analysis of experiments on magnetooscillations (in particular, for extracting the value of the effective mass) and are expected to be useful for understanding the physics of a high-mobility 2DEG near the apparent metal-insulator transition.Comment: 24 pages; subsection adde

    Spin Dependent Fragmentation Functions for Heavy Flavor Baryons and Single Heavy Hyperon Polarization

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    Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. Λb\Lambda_b , Λc\Lambda_c and Ξc\Xi_c production rate and polarization at LEP energies are calculated and, where possible, compared with experiment. A different approach, also relying on a heavy quark-diquark model, is proposed for the small momentum transfer inclusive production of polarized heavy flavor hyperons. The predicted Λc\Lambda_c polarization is roughly in agreement with experiment.Comment: LaTeX2e 11 pages with 4 PostScript figures. To be published in Proceedings of the International Workshop ``Symmetries and spin'', Praha-SPIN-200

    Decay of the classical Loschmidt echo in integrable systems

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    We study both analytically and numerically the decay of fidelity of classical motion for integrable systems. We find that the decay can exhibit two qualitatively different behaviors, namely an algebraic decay, that is due to the perturbation of the shape of the tori, or a ballistic decay, that is associated with perturbing the frequencies of the tori. The type of decay depends on initial conditions and on the shape of the perturbation but, for small enough perturbations, not on its size. We demonstrate numerically this general behavior for the cases of the twist map, the rectangular billiard, and the kicked rotor in the almost integrable regime.Comment: 8 pages, 3 figures, revte

    Loschmidt Echo and Lyapunov Exponent in a Quantum Disordered System

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    We investigate the sensitivity of a disordered system with diffractive scatterers to a weak external perturbation. Specifically, we calculate the fidelity M(t) (also called the Loschmidt echo) characterizing a return probability after a propagation for a time tt followed by a backward propagation governed by a slightly perturbed Hamiltonian. For short-range scatterers we perform a diagrammatic calculation showing that the fidelity decays first exponentially according to the golden rule, and then follows a power law governed by the diffusive dynamics. For long-range disorder (when the diffractive scattering is of small-angle character) an intermediate regime emerges where the diagrammatics is not applicable. Using the path integral technique, we derive a kinetic equation and show that M(t) decays exponentially with a rate governed by the classical Lyapunov exponent.Comment: 9 pages, 7 figure

    Measurement of the cosmic ray hadron spectrum up to 30 TeV at mountain altitude: the primary proton spectrum

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    The flux of cosmic ray hadrons at the atmospheric depth of 820 g/cm^2 has been measured by means of the EAS-TOP hadron calorimeter (Campo Imperatore, National Gran Sasso Laboratories, 2005 m a.s.l.). The hadron spectrum is well described by a single power law : S(E_h) = (2.25 +- 0.21 +- 0.34(sys)) 10^(-7)(E_h/1000)^(-2.79 +- 0.05) m^(-2) s^(-1) sr^(-1) GeV^(-1) over the energy range 30 GeV-30 TeV. The procedure and the accuracy of the measurement are discussed. The primary proton spectrum is derived from the data by using the CORSIKA/QGSJET code to compute the local hadron flux as a function of the primary proton spectrum and to calculate and subtract the heavy nuclei contribution (basing on direct measurements). Over a wide energy range E_0 = 0.5-50 TeV its best fit is given by a single power law : S(E_0) = (9.8 +- 1.1 +- 1.6(sys)) 10^(-5) (E_0/1000)^(-2.80 +- 0.06) m^(-2) s^(-1) sr^(-1) GeV^(-1). The validity of the CORSIKA/QGSJET code for such application has been checked using the EAS-TOP and KASCADE experimental data by reproducing the ratio of the measured hadron fluxes at the two experimental depths (820 and 1030 g/cm^2 respectively) at better than 10% in the considered energy range.Comment: 16 pages, 9 figures, accepted for publication in Astroparticle Physic
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