600 research outputs found

    One-dimensional Dirac oscillator in a thermal bath

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    We analyze the one-dimensional Dirac oscillator in a thermal bath. We found that the heat capacity is two times greater than the heat capacity of the one-dimensional harmonic oscillator for higher temperatures.Comment: 4 pages, 3 figures, to appear in Physics Letters

    Consistent deformations method applied to a topological coupling of antisymmetric gauge fields in D=3

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    In this work we use the method of consistent deformations of the master equation by Barnich and Henneaux in order to prove that an abelian topological coupling between a zero and a two form fields in D=3 has no nonabelian generalization. We conclude that a topologically massive model involving the Kalb-Ramond two-form field does not admit a nonabelian generalization. The introduction of a connection-type one form field keeps the previous result.Comment: 8 pages. To appear in Physics Letters

    Topologically massive nonabelian BF models in arbitrary space-time dimensions

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    This work extends to the D-dimensional space-time the topological mass generation mechanism of the nonabelian BF model in four dimensions. In order to construct the gauge invariant nonabelian kinetic terms for a (D-2)-form B and a 1-form A, we introduce an auxiliary (D-3)-form V. Furthermore, we obtain a complete set of BRST and anti-BRST transformation rules of the fields using the so called horizontality condition, and construct a BRST/anti-BRST invariant quantum action for the model in D-dimensional space-time.Comment: 7 page

    Supplementation of diets for piglets with L-Arginine and powdered whole milk

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    The objective of this study was to evaluate the supplementation of L-Arginine in diets with and without dairy products for piglets weaned at 21 days old. Thirty-two animals with initial mean weight of 5.16 ± 1.92 kg and from the same commercial lineage were allocated in a randomized block design to four diets. The experimental diets consisted of a corn and soybean meal-based diet (NDD), the same diet supplemented with 0.6% L-Arginine (NDDA), the diet supplemented with powdered whole milk (DD), and the diet supplemented with powdered whole milk and 0.6% of L-Arginine (DDA). At 43 days old, 16 animals were slaughtered. The productive performance, incidence of diarrhoea, serum parameters, relative organ weight, morphometry and intestinal health were evaluated. Supplementation with 0.6% of L-Arginine increased (P <0.05) the daily and final weight gain of the piglets at 32 days old and reduced the incidence of diarrhoea. DDA promoted a higher villi to crypt ratio (P <0.05). There was a lower rate of mitosis and apoptosis in the jejunum of animals fed DD and DDA. The non-dairy diet supplemented with 0.6% arginine (NDDA) increased serum immunoglobulin A (IgA) and Immunoglobulin G (IgG) concentrations compared with NDD (P <0.05). Thus, supplementation with 0.6% L-Arginine increased immunological activity, improved intestinal integrity, and reduced the incidence of diarrhoea

    Eliminating Infrared Divergences in the Pressure

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    The pressure of a system in thermal equilibrium is expressed as a mass integral over a sum of thermal propagators. This allows a Dyson resummation and is used to demonstrate that potential infrared divergences are rendered harmless.Comment: 6 pages plain tex, including figures embedded using eps

    Generating mass and topological terms to the antisymmetric tensor matter field by Higgs mechanism

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    The interaction between the complex antisymmetric tensor matter field and a scalar field is constructed. We analyze the Higgs mechanism and show the generation of mass and topological terms by spontaneous symmetry breaking.Comment: Accepted for publication in Phys. Lett.

    Coping with suboptimal water temperature: modifications in blood parameters, body composition, and postingestive-driven diet selection in Nile tilapia fed two vegetable oil blends

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    The world tilapia production faces seasonal variations. However, very few nutritional studies have addressed suboptimal temperature. We evaluated the effect of two temperatures (20 or 30 °C) and two vegetable oil blends (one rich in corn oil (COR) and one rich linseed oil (LIN)) on tilapia growth, body composition, and blood parameters using a 2 × 2 factorial design with the following treatments: COR-20; LIN-20; COR-30; LIN-30 (Trial 1). In addition, we also evaluated the effect of postingestive signals of dietary oils when the organoleptic properties of diets were isolated (Trial 2). In the Trial 1, 256 fish (15.36 ± 0.14 g) were placed in 16 aquariums and submitted during 30 days to the 2 × 2 factorial designs: COR-20; LIN-20; COR-30; LIN-30. The temperatures were established in two independent water recirculation systems. In the Trial 2, 96 fish (34.02 ± 0.79 g) were placed in 12 aquariums and subjected to the same experimental design of Trial 1, but to evaluate fish feeding behavior. They were allowed to select the encapsulated diets provided in different feeding halls to evaluate if diet preferences are influenced by postingestive signals. As the Trial 1 results show, diets had no significant effects on growth, dietary protein use, and body centesimal composition, but 30 °C induced the best performance and protein deposition (P < 0.05). LIN-20 showed lower very-low-density lipoprotein and cortisol, but higher high-density lipoprotein (HDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and triglycerides (TG) than COR-20 (P < 0.05). COR-30 presented higher HDL, AST, ALT, TG, and cortisol than LIN-30. The fish fed COR showed lower C20:5n-3 (EPA) and higher n-6 than fish fed LIN (P < 0.05). The fish fed LIN had high n-3 highly unsaturated fatty acid. ∑ polyunsaturated fatty acid was higher at 30 °C. Finally, the tilapia in Trial 2 showed clear diet intake regulation and preference for LIN (P < 0.05), regardless of temperature. In short, lipid sources had no influence on tilapia performance; however, temperature affects carcass lipid deposition as well as fatty acids profile. Notably, the preference for linseed oil can suggest nutritional metabolic issues, contributing to animal behavior knowledge

    QUANTIFICAÇÃO HISTOLÓGICA DA ESPERMATOGÊNESE DE RATOS WISTAR TRATADOS COM DIMETIL SULFÓXIDO

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    Avaliaram-se através de histologia testicular quantitativa os efeitos da ação do Dimetil Sulfóxido (DMSO) na espermatogênese de 28 ratos adultos albinos da raça Wistar. Os animais foram divididos em dois grupos - Controle e Experimental - e submetidos a dois tipos de tratamento: no primeiro tratamento, o Grupo Experimental (10 animais) recebeu aplicações tópicas de DMSO no jarrete, duas vezes ao dia, na dosagem de 1 g/kg-1 de peso vivo, durante sete dias consecutivos; no segundo tratamento, o Grupo Experimental (7 animais) recebeu aplicações tópicas de DMSO no escroto duas vezes ao dia, na dosagem de 1 g/kg-1 de peso vivo, durante 54 dias consecutivos; os Grupos Controles (8 e 3 animais) receberam aplicações de solução salina friccionada na pele do jarrete e do escroto duas vezes ao dia, por período equivalente ao dos tratamentos, respectivamente. Proporções volumétricas dos componentes do parênquima testicular, diâmetro dos túbulos seminíferos, contagem dos elementos celulares do epitélio seminífero e rendimento intrínseca da espermatogênese não apresentaram diferença significativa entre os grupos Controles e Experimentais. O processo espermatogênico não sofreu alteração após a aplicação do DMSO. Histological quantification of spermatogenesis in dimethyl sulfoxide treated wistar rats Abstract In order to provide a more accurate analysis on the effects of dimethyl sulfoxide (DMSO) on spermatogenesis in mammals, an experiment was carried out with albino Wistar rats. A total of 28 rats, 78 days old and average weight of 325 g were divided in one control group and two experimental groups - G1 and G2. Rats from G1 were treated with topic applications of DMSO in the hock twice a day at a dosage of 1.0 g/kg of live weight for 7 consecutive days. Rats from G2 received topic applications of DMSO at the scrotum twice a day at a dosage of 1.0 g/kg of live weight for 54 consecutive days. The control group was swabbed with saline on the hock and the scrotal skin twice a day for the same period as the treatment of G1 and G2 groups. Volumetric proportions of the testicular parenchyma, diameter of the somniferous tubules, counting of cell types in the somniferous epithelium and intrinsic spermatogenesis yield showed no significant differences (

    The effect of pH on the simultaneous determination of Sulfamethoxazole and Trimethoprim by Ultraviolet Spectrophotometry and Multivariate Calibration

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    Analytical techniques based on Ultraviolet (UV) spectrophotometry are widely used in pharmaceutical analysis, because they are simple and inexpensive. The choice of pH is critical in the development of univariate methods for pharmaceutical quantitation by UV spectrophotometry since changes may modify the absorption spectrum profile. Similar to univariate methods by UV spectrophotometry changes in pH may influence the predictive ability of multivariate models, affecting the resultant analytical performance. We report herein on the influence of pH on the simultaneous determination of sulfamethoxazole (SMZ) and trimethoprim (TMP) in tablets using UV spectrophotometry and multivariate calibration. Data were recorded using a UV spectrophotometer in the wavelength range of 200 to 350 nm. The experimental matrix was constructed using 36 synthetic samples of SMZ-TMP mixtures. The concentration ranges used for the investigation were 14.0 to 26.0 mg L-1 for SMZ and 2.8 to 5.2 mg L-1 for TMP. The Partial Least Squares (PLS) regression models were generated with full-spectrum and multiple pH levels. At pH 4.3, lower values of relative standard error of prediction (RSEP %) for SMZ (1.83) and TMP (1.13) were obtained. The PLS model at pH 4.3 was used for the quantification of real samples (tablets obtained from 13 different manufacturers) and the results were compared with conventional procedures using high performance liquid chromatography (HPLC).
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