990 research outputs found

    Approximate dual representation for Yang-Mills SU(2) gauge theory

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    An approximate dual representation for non-Abelian lattice gauge theories in terms of a new set of dynamical variables, the plaquette occupation numbers (PONs) that are natural numbers, is discussed. They are the expansion indices of the local series of the expansion of the Boltzmann factors for every plaquette of the Yang-Mills action. After studying the constraints due to gauge symmetry, the SU(2) gauge theory is solved using Monte Carlo simulations. For a PONs configuration the weight factor is given by Haar-measure integrals over all links whose integrands are products of powers of plaquettes. Herein, updates are limited to changes of the PON at a plaquette or all PONs on a coordinate plane. The Markov chain transition probabilities are computed employing truncated maximal trees and the Metropolis algorithm. The algorithm performance is investigated with different types of updates for the plaquette mean value over a large range of β\betas. Using a 12412^4 lattice very good agreement with a conventional heath bath algorithm is found for the strong and weak coupling limits. Deviations from the latter being below 0.1% for 2.5<β<32.5 < \beta < 3. The mass of the lightest JPC=0++J^{PC}=0^{++} glueball is evaluated and reproduces the results found in the literature

    Protein metabolism, feed energy partitioning, behavior patterns and plasma cortisol in Nellore steers with high and low residual feed intake.

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    The objective was to evaluate protein turnover, nitrogen balance, feed energy partitioning, behavior patterns and plasma cortisol in Nellore (B. indicus) cattle with high and low residual feed intake (RFI = actual minus expected dry matter intake). Seventy-two Nellore steers (16 to 21 months-old, 334±19 kg initial body weight) were fed a feedlot diet for 70 days ad libitum. Daily dry matter intake (DMI) and average daily gain (ADG) were recorded individually and RFI was calculated. The 12 steers of lowest (Low-RFI, most efficient) RFI and the 12 ones of highest RFI (High-RFI, least efficient) were evaluated with respect to their behavior patterns and plasma cortisol concentration. Urine was collected for determination of daily 3-methylhistidine excretion (3MH) and myofibrillar protein breakdown rates. Urinary, gaseous and fecal energy losses were determined as well as the N retention and excretion. High-RFI steers tended to have shorter lying and idle periods and greater feeding time and plasma cortisol levels than low-RFI cattle. No RFI effects were seen for urine 3MH excretion and for rates of protein degradation and synthesis. No effects of efficiency class were observed for N excretion or N retention. No RFI effects were observed for dry matter digestibility, digestible energy (DE) and metabolizable energy (ME) content and DE/ME ratio. Methane energy losses were lower for low- compared with high-RFI steers. Protein turnover seems not to affect feed efficiency in Nellore steers. Improved RFI in Nellore steers is probably associated with lower degrees of activity and responsiveness to stress and lower losses of dietary energy as methane

    Power to mechanical power to minimize ventilator-induced lung injury?

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    Mechanical ventilation is a life-supportive therapy, but can also promote damage to pulmonary structures, such as epithelial and endothelial cells and the extracellular matrix, in a process referred to as ventilator-induced lung injury (VILI). Recently, the degree of VILI has been related to the amount of energy transferred from the mechanical ventilator to the respiratory system within a given timeframe, the so-called mechanical power. During controlled mechanical ventilation, mechanical power is composed of parameters set by the clinician at the bedside-such as tidal volume (VT), airway pressure (Paw), inspiratory airflow (V'), respiratory rate (RR), and positive end-expiratory pressure (PEEP) level-plus several patient-dependent variables, such as peak, plateau, and driving pressures. Different mathematical equations are available to calculate mechanical power, from pressure-volume (PV) curves to more complex formulas which consider both dynamic (kinetic) and static (potential) components; simpler methods mainly consider the dynamic component. Experimental studies have reported that, even at low levels of mechanical power, increasing VT causes lung damage. Mechanical power should be normalized to the amount of ventilated pulmonary surface; the ratio of mechanical power to the alveolar area exposed to energy delivery is called "intensity." Recognizing that mechanical power may reflect a conjunction of parameters which may predispose to VILI is an important step toward optimizing mechanical ventilation in critically ill patients. However, further studies are needed to clarify how mechanical power should be taken into account when choosing ventilator settings

    Atropelamentos e novos registros para tatu-canastra (Priodontes maximus) no centro-oeste do Brasil

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    Despite the widespread distribution of the giant armadillo Priodontes maximus, this species isfound at low densities, often in disrupted populations. Here we report 12 new records, including five incidentsof roadkill of P. maximus in different points of the Cerrado and one in an Atlantic Forest fragment in centralwesternBrazil. In addition to the relevant records, we discuss the negative effects of roadkills, which is a seriousissue for the conservation and maintenance of local populations of giant armadillo.Atropelamentos e novos registros para tatu-canastra (Priodontes maximus) no centro-oeste do Brasil. Apesar da ampla distribuição do tatu-canastra Priodontes maximus, esta espécie apresenta baixas densidades em populações não conectadas. Aqui, relatamos 12 novos registros, incluindo cinco atropelamentos rodoviários de P. maximus em diferentes pontos de Cerrado e um em fragmento de Floresta Atlântica no centro-oeste do Brasil. Além dos registros relevantes, discutimos o efeito negativo da perda de espécimes por atropelamentos em estradas, o qual é um problema sério para a conservação e manutenção de populações locais de tatu-canastra.Fil: Hannibal, Wellington. Universidade Federal de Goiás; BrasilFil: Leme Da Cunha, Nicolay. Universidade Federal do Mato Grosso do Sul; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Dalponti, Guilherme. Universidade Federal do Mato Grosso do Sul; BrasilFil: Oliveira, Seixas R.. Instituto Federal Goiano; BrasilFil: Pereira, Katia R. F.. Universidade Anhaguera; Brasi

    Monensin and functional oil addition in feed behavior and methane emission of Nellore bulls fed low-fiber diets.

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    In order to minimize unwanted effects of high levels of grains in feedlot diet, antibiotic feed additives are used, but its security is challenged and the discovery of alternative natural substances becomes necessary. The aim of the study was to evaluate the effect of increasing levels of the forage neutral detergent fiber (NDFf) and additives in feeding behavior and enteric methane emissions. Seventy Nellore bulls, (408 ± 14.17 kg initial LW), were distributed in a factorial arrangement 2 x 3 + 1, where two additives (500 mg kg-1 DM, of a blend of castor oil and cashew nut shell liquid, Essential Oligo Basics, Brazil, or 30 mg kg-1 DM of monensin), three levels of NDFf (6, 9 and 15% in DM), and control group, without additive. The diet was composed by Brachiaria hay, ground corn, citrus pulp, soybean meal and mineral salt. The experiment lasted 105d, the enteric methane emission was estimated by indicator gas SF6 methodology, in two collections for five straight days, the intake behavior was performed through rumination sensors (Heatime® HR), evaluated in five animal per treatment. Data were analyzed using the SAS´s MIXED, 5% significance evaluated by contrasts. The monensina increased (P<0.05) the dry matter intake (DMI), final live weight (FLW), and methane emission compared to oil treatment, the averages 8.29 ± 0.06 kg d-1, 518.73 ± 5.7 kg and 183.22 ± 4.6 g d-1 for monensin and 7.48 ± 0.04 kg d-1; 489.8 ± 8.9 kg and 161.33 ± 4.83 g d-1 for functional oil. Regarding the NDFf levels, the DMI was higher for 15% of NDFf compared to other levels (P = 0.0156), the averages were respectively 8.69 ± 0.03, 7.10 ± 0.04 and 7.99 ± 0.05 kg d-1. The methane emission increased (P = 0.0006) as the NDFf level was increased (139.03 ± 4.97; 165.51 ± 3.4 and 213.72 ± 4.64 g d-1 for the 6 and 9% levels, respectively), with no changes when methane was analyzed by kg of DMI (P = 0.1308). There was an effect on NDFf levels on rumination time (P = 0.0106) with 23.25 ± 0.62; 21.30 ± 0.30 and 26.94 ± 0.43 kg of DM d-1 for 6, 9 e 15% levels, respectively. As well the monensina increased (P = 0.0030) the rumination time compared to the functional oil (25.56 ± 0.38 and 23.98 ± 0.49 kg of DM d-1 respectively). The diet with 15% of NDFf and the monensin were more effective in DMI, FLW and rumination, the functional oil contributed to the reduction of enteric methane emission

    Effect of flint corn processing method and roughage level on finishing performance of Nellore-based cattle

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    Citation: Caetano, M., Goulart, R. S., Silva, S. L., Drouillard, J. S., Leme, P. R., & Lanna, D. P. D. (2015). Effect of flint corn processing method and roughage level on finishing performance of Nellore-based cattle. Journal of Animal Science, 93(8), 4023-4033. doi:10.2527/jas2015-9051This study was conducted to evaluate the effects of flint corn processing method (CPM) and level of NDF from roughage (rNDF) on performance, carcass characteristics, and starch utilization by finishing Nellore-based cattle fed high-concentrate, flint corn-based diets. In this study, 112 Nellore type bulls (initial BW 384.07 +/- 29.53 kg and 24-36 mo of age) were individually fed using Calan gates or individual pens. The animals were used in a randomized complete block design in a 2 x 4 factorial arrangement with 2 CPM, high-moisture flint corn (HMC) or finely ground dry flint corn (FGC), with 1 of 4 levels of rNDF, 3, 8, 13, and 18% (DM basis), using sugarcane silage (SS) as roughage. Bulls were adapted to the finishing diet over a 21-d period and fed for a total of 81 d. Fecal starch (FS) concentration was determined on d 46 and 74 of the feeding period. There was a quadratic effect of rNDF on final BW (P < 0.01) and ADG (P = 0.01). Optimal concentrations of rNDF were estimated using the first derivative of second order polynomials, indicating that final BW and ADG were maximized with 13.3 and 13.0% rNDF, respectively. An interaction was observed between CPM and rNDF (P = 0.05) for DMI, with peak DMI occurring at 11.3 and 13.7% rNDF with FGC and HMC, respectively. Cattle fed HMC had 13.9% greater G:F (P < 0.01) compared with those fed FGC (0.172 vs. 0.151, respectively). There were quadratic effects of rNDF on HCW (P = 0.04) and ME intake (P < 0.01); heaviest carcass weights were estimated, in both cases, to be achieved with 12.8% rNDF. A quadratic effect of rNDF for renal, pelvic, and inguinal fat weight (P = 0.04) was observed, with a peak estimated to occur at 12.6% rNDF. An interaction between CPM and rNDF also was observed for FS (P < 0.05). Bulls fed FGC with 3% rNDF had greater FS content, and FS linearly decreased as concentration of rNDF increased. For bulls fed HMC, FS was 3.0% of DM and was unaffected by rNDF in the diet. Lower FS from bulls fed HMC suggests that availability of starch from flint corn was greater than that of FGC. For Nellore-based cattle fed a flint corn-based diet containing SS and 8% whole lint cottonseed, performance was optimized with 12.8% rNDF. In the absence of cottonseed addition to diets, optimal performance would be expected with about 14.5% rNDF
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