454 research outputs found

    Subproducts of beer industry in swine feeding and its influence in the quantity and quality of fat deposits

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    Se ensayaron dos subproductos de la industria cervecera en la alimentación del cerdo (raicilla y medio grano) que suplantaron a una parte del cereal. Un total de 33 porcinos fueron divididos en dos lotes, lote testigo LT 16 animales que fueron alimentados con trigo y harina de carne y lote experiencia LE 17 animales en el cual los subproductos reemplazaron al trigo en una proporción del 37,5, 45,5, 55,5% respectivamente segun los tres niveles de requerimientos alimenticios del cerdo. Se demostró que se pueden suplantar parte de los granos por dichos subproductos sin afectar la producción. Hubo un aumento del tenor de celulosa bruta en la ración del LE de 1,81, 2,5 y 3 g. 100 g. con respecto a los tres niveles del LT lo que ocasionó una dilución energética de la ración y de esta manera los cerdos del LE estuvieron 21 días más de promedio en experiencia que el LT para obtener la misma ganancia de peso (82,2 kg.) pero consumieron 18 kg. menos de alimento por animal. Con respecto al espesor de grasa solamente el 11,7% de los animales del LE superó los 26 mm de espesor a la altura de la última costilla, mientras que el 82,5% de los animales del LT superaron ese espesor. Se obtuvo una reducción del costo de producción del 19% para el LE debido al menor costo de producción de la ración y al menor consumo de la misma sobre todo en el tercer período de terminación de los cerdos.Two beer brewery buproducts malt sprounts and second grade brewers barley grain, were used in these feed trials for pigs replacing part of the traditional grain. A total of 33 pigs was divided into 2 lots: Control Lot (LT) of 16 animals was fed with wheat and dried meat. Trial Lot (LE) of 17 animals was fed replacing the wheat with by products in the proportion of 37,5 45,5 and 55,5% respectively, according to the 3 feed requirement levels of the pig. It was shown that part of the grains can be replaced by these by-products without affecting the production. There was an increase in the tenor of crude fiber in the ration of LE of 1,81, 2,5 and 3 g 100 according to three levels of LT which caused an energetic dilution of the ration arid in this way the pigs of the LE were 21 more days average in experience thaai LT in order to obtain the same increase of weight (82,2 kg.) but consuming 18 kg. less of food each animal. With regard to the thickness of dorsal fat only the 11,7% of the animals of LE overcame the 26 mm of thickness up to the last rib, while the 82,5% of the animais of LT overcame that thickness. There was a disminution in the cost of production of 19% for the LE owed to a smaller consume of the same specially in the third period of finishing pigs.Facultad de Ciencias Veterinaria

    Localization length in a random magnetic field

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    Kubo formula is used to get the d.c conductance of a statistical ensemble of two dimensional clusters of the square lattice in the presence of random magnetic fluxes. Fluxes traversing lattice plaquettes are distributed uniformly between minus one half and plus one half of the flux quantum. The localization length is obtained from the exponential decay of the averaged conductance as a function of the cluster side. Standard results are recovered when this numerical approach is applied to Anderson model of diagonal disorder. The localization length of the complex non-diagonal model of disorder remains well below 10 000 (in units of the lattice constant) in the main part of the band in spite of its exponential increase near the band edges.Comment: 12 two-column pages including 10 figures (epsfig), revtex, to appear in PR

    Interrelationships Between the Kinetics of VLDL Subspecies and HDL Catabolism in Abdominal Obesity: A Multicenter Tracer Kinetic Study

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    Context: Low plasma high-density lipoprotein (HDL) cholesterol is a major abnormality in abdominal obesity. This relates due to accelerated HDL catabolism, but the underlying mechanism requires further elucidation. The relationships between HDL catabolism and other variables that may be modified in abdominal obesity, such as very low-density lipoprotein (VLDL) subspecies (VLDL1, VLDL2) kinetics, liver fat, or visceral adiposity, remain to be investigated. Objectives: Our aim was to study the associations between HDL apolipoprotein (apo)-A-I fractional catabolic rate (FCR) and the kinetics of VLDL subspecies and estimates of liver and visceral and sc fat. Design: We carried out a multicenter in vivo kinetic study using stable isotopes (deuterated leucine and glycerol) in 62 individuals with abdominal obesity. Results: In a multivariate analysis, among the morphological and biological parameters that may predict apoA-I FCR, liver fat (beta = .400, P = .003), and VLDL1-apoB (beta = .307, P = .020) were independently associated with apoA-I FCR. In a multivariate analysis, among the kinetic parameters, VLDL1-triglycerides (TGs) indirect FCR (beta = .357, P = .001), VLDL1-TG production rate (beta = 0.213, P = .048), and apoA-II FCR (beta = .667, P < .0001) were independently associated with apoA-I FCR. After adjustment for VLDL1-TG production rate, liver fat was no more correlated with apoA-I FCR. No association between apoA-I FCR and visceral fat was observed. Conclusions: We show that VLDL1 is an important independent determinant of apoA-I FCR and more precisely that apoA-I FCR is independently associated with both catabolism and the production of VLDL1-TG. In addition, we show an association between liver fat and apoA-I FCR that is mostly mediated by VLDL1-TG production. These data indicate that, in abdominal obesity, dysfunctional VLDL1 metabolism is an important modulator of HDL apoA-I catabolism

    Phase diagrams of the 2D t-t'-U Hubbard model from an extended mean field method

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    It is well-known from unrestricted Hartree-Fock computations that the 2D Hubbard model does not have homogeneous mean field states in significant regions of parameter space away from half filling. This is incompatible with standard mean field theory. We present a simple extension of the mean field method that avoids this problem. As in standard mean field theory, we restrict Hartree-Fock theory to simple translation invariant states describing antiferromagnetism (AF), ferromagnetism (F) and paramagnetism (P), but we use an improved method to implement the doping constraint allowing us to detect when a phase separated state is energetically preferred, e.g. AF and F coexisting at the same time. We find that such mixed phases occur in significant parts of the phase diagrams, making them much richer than the ones from standard mean field theory. Our results for the 2D t-t'-U Hubbard model demonstrate the importance of band structure effects.Comment: 6 pages, 5 figure

    Formulae for zero-temperature conductance through a region with interaction

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    The zero-temperature linear response conductance through an interacting mesoscopic region attached to noninteracting leads is investigated. We present a set of formulae expressing the conductance in terms of the ground-state energy or persistent currents in an auxiliary system, namely a ring threaded by a magnetic flux and containing the correlated electron region. We first derive the conductance formulae for the noninteracting case and then give arguments why the formalism is also correct in the interacting case if the ground state of a system exhibits Fermi liquid properties. We prove that in such systems, the ground-state energy is a universal function of the magnetic flux, where the conductance is the only parameter. The method is tested by comparing its predictions with exact results and results of other methods for problems such as the transport through single and double quantum dots containing interacting electrons. The comparisons show an excellent quantitative agreement.Comment: 18 pages, 18 figures; to appear in Phys. Rev.

    Propagation of social representations

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    Based on a minimal formalism of social representations as a set of associated cognems, a simple model of propagation of representations is presented. Assuming that subjects share the constitutive cognems, the model proposes that mere focused attention on the set of cognems in the field of common conscience may replicate the pattern of representation from context into subjects, or, from subject to subject, through actualization by language, where cognems are represented by verbal signs. Limits of the model are discussed, and evolutionist perspectives are presented with the support of field data

    Effect of acute hypoxia on respiratory muscle fatigue in healthy humans

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    <p>Abstract</p> <p>Background</p> <p>Greater diaphragm fatigue has been reported after hypoxic versus normoxic exercise, but whether this is due to increased ventilation and therefore work of breathing or reduced blood oxygenation per se remains unclear. Hence, we assessed the effect of different blood oxygenation level on isolated hyperpnoea-induced inspiratory and expiratory muscle fatigue.</p> <p>Methods</p> <p>Twelve healthy males performed three 15-min isocapnic hyperpnoea tests (85% of maximum voluntary ventilation with controlled breathing pattern) in normoxic, hypoxic (SpO<sub>2 </sub>= 80%) and hyperoxic (FiO<sub>2 </sub>= 0.60) conditions, in a random order. Before, immediately after and 30 min after hyperpnoea, transdiaphragmatic pressure (P<sub>di,tw </sub>) was measured during cervical magnetic stimulation to assess diaphragm contractility, and gastric pressure (P<sub>ga,tw </sub>) was measured during thoracic magnetic stimulation to assess abdominal muscle contractility. Two-way analysis of variance (time x condition) was used to compare hyperpnoea-induced respiratory muscle fatigue between conditions.</p> <p>Results</p> <p>Hypoxia enhanced hyperpnoea-induced P<sub>di,tw </sub>and P<sub>ga,tw </sub>reductions both immediately after hyperpnoea (P<sub>di,tw </sub>: normoxia -22 ± 7% vs hypoxia -34 ± 8% vs hyperoxia -21 ± 8%; P<sub>ga,tw </sub>: normoxia -17 ± 7% vs hypoxia -26 ± 10% vs hyperoxia -16 ± 11%; all <it>P </it>< 0.05) and after 30 min of recovery (P<sub>di,tw </sub>: normoxia -10 ± 7% vs hypoxia -16 ± 8% vs hyperoxia -8 ± 7%; P<sub>ga,tw </sub>: normoxia -13 ± 6% vs hypoxia -21 ± 9% vs hyperoxia -12 ± 12%; all <it>P </it>< 0.05). No significant difference in P<sub>di,tw </sub>or P<sub>ga,tw </sub>reductions was observed between normoxic and hyperoxic conditions. Also, heart rate and blood lactate concentration during hyperpnoea were higher in hypoxia compared to normoxia and hyperoxia.</p> <p>Conclusions</p> <p>These results demonstrate that hypoxia exacerbates both diaphragm and abdominal muscle fatigability. These results emphasize the potential role of respiratory muscle fatigue in exercise performance limitation under conditions coupling increased work of breathing and reduced O<sub>2 </sub>transport as during exercise in altitude or in hypoxemic patients.</p

    Constrained-path quantum Monte Carlo simulations of the zero-temperature disordered two-dimensional Hubbard model

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    We study the effects of disorder on long-range antiferromagnetic correlations in the half-filled, two dimensional, repulsive Hubbard model at T=0. A mean field approach is first employed to gain a qualitative picture of the physics and to guide our choice for a trial wave function in a constrained path quantum Monte Carlo (CPQMC) method that allows for a more accurate treatment of correlations. Within the mean field calculation, we observe both Anderson and Mott insulating antiferromagnetic phases. There are transitions to a paramagnet only for relatively weak coupling, U < 2t in the case of bond disorder, and U < 4t in the case of on-site disorder. Using ground-state CPQMC we demonstrate that this mean field approach significantly overestimates magnetic order. For U=4t, we find a critical bond disorder of Vc = (1.6 +- 0.4)t even though within mean field theory no paramagnetic phase is found for this value of the interaction. In the site disordered case, we find a critical disorder of Vc = (5.0 +- 0.5)t at U=4t.Comment: Revtex, 13 pages, 15 figures. Minor changes to title and abstract, discussion and references added, figures 5, 6, 8, 9 replaced with easier to read version

    Tricritical Point and the Doping Dependence of the Order of the Ferromagnetic Phase Transition of La1-xCaxMnO3

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    We report the doping dependence of the order of the ferromagnetic metal to paramagnetic insulator phase transition in La1-xCaxMnO3. At x = 0.33, magnetization and specific heat data show a first order transition, with an entropy change (2.3 J/molK) accounted for by both volume expansion and the discontinuity of M ~ 1.7 Bohr magnetons via the Clausius-Clapeyron equation. At x = 0.4, the data show a continuous transition with tricritical point exponents alpha = 0.48+/- 0.06, beta = 0.25+/- 0.03, gamma = 1.03+/- 0.05, and delta = 5.0 +/- 0.8. This tricritical point separates first order (x<0.4) from second order (x>0.4) transitions.Comment: 14 pages, including 4 figures: i.e. 10 pages of text and 4 pages of figures. to appear in Physical Review Letters (accepted

    Pairing fluctuations and pseudogaps in the attractive Hubbard model

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    The two-dimensional attractive Hubbard model is studied in the weak to intermediate coupling regime by employing a non-perturbative approach. It is first shown that this approach is in quantitative agreement with Monte Carlo calculations for both single-particle and two-particle quantities. Both the density of states and the single-particle spectral weight show a pseudogap at the Fermi energy below some characteristic temperature T*, also in good agreement with quantum Monte Carlo calculations. The pseudogap is caused by critical pairing fluctuations in the low-temperature renormalized classical regime ω<T\omega < T of the two-dimensional system. With increasing temperature the spectral weight fills in the pseudogap instead of closing it and the pseudogap appears earlier in the density of states than in the spectral function. Small temperature changes around T* can modify the spectral weight over frequency scales much larger than temperature. Several qualitative results for the s-wave case should remain true for d-wave superconductors.Comment: 20 pages, 12 figure
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