1,086 research outputs found

    Effect of breed on meat quality and global acceptance of native lambs and their crosses

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    International projections point to the growth in global production of sheep meat, mainly from developing countries. However, the exigencies of consumers on characterization of production systems, nutritional information, and sensorial analysis to target the preferences must be answered. The aim of this study was to characterize the meat quality and the global acceptance of Brazilian native ovine breeds and their crosses, and discuss these aspects on the current basis of human health and wellbeing. Three native breeds (Morada Nova, Rabo Largo, and Santa Inês) that were managed in semi-intensive systems and raised in semi-arid Brazilian regions were used. Chemical composition and fatty acid analysis, sensory evaluation and health indices were accessed. The combined effects of breed, sex and breed by sex interaction produced differentiation in meat fatty acid (FA) profiles. The cholesterol contents ranged between 51 and 59.1 mg/100 g. The Morada Nova lambs showed the lowest lipid content (1.93%). The Morada Nova x Rabo Largo crossbreed breed has the potential to increase the content of conjugated linoleic acid. The high content of α-linolenic acid, which is considered hypocholesterolemic, was responsible for better health indices. The moderate acceptability obtained in sensory traits is compatible with the requirements of the consumer market. The combination of nutritional and sensory traits associated with human health and wellbeing that is presented by these native ovine breeds qualifies them as a good choice of red meat to be included in a larger proportion in human food. Keywords: fatty acids, healthier meat, semi-arid region, shee

    Spin-hybrid-phonon resonance in anisotropic quantum dots

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    We have studied the absorption of electromagnetic radiation of an anisotropic quantum dot taking into account the spin-flip processes that is associated with the interaction of the electrons with optical phonons. It is shown that these processes lead to the resonance absorption. Explicit formula is derived for the absorption coefficient. The positions of the resonances peaks are found

    Dried brewers grains in growing rabbits: nutritional value and effects on performance

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    [EN] Two assays were carried out to determine i) the nutritional value of dried brewers’ grains and ii) the effects of inclusion of this ingredient in growing rabbit diets on animal performance and economic performance of the breeding unit. In the digestibility assay, a total of 28 male rabbits were distributed in 2 groups differing in the diet offered to animals: a reference diet (35.51% neutral detergent fibre and 16.50% crude protein [CP]) and a test diet (60% of reference diet and 40% of dried brewers grains). The dried brewers’ grain contained 37.9% of CP and 3371 kcal digestible energy/kg dry matter. In the performance study, 80 weaned rabbits (40 males and 40 females) were allotted at 40 d of age to 5 groups differing in the inclusion levels of dried brewers’ grains (0, 7, 14, 21 and 28%) from 40 d to 90 d of age. Inclusion of dried brewers’ grains did not affect the live weight at 90 d, the feed intake between 40 d and 90 d or the dressing percentage of rabbits (on average 223 g, 96 g/d and 51.3%, respectively). There was no effect of diet on the meat quality parameters (69.5% water holding capacity, 25.6% cooking loss, 3.4 kg/cm2 Warner-Bratzler shear force and pH 5.70) and inclusion levels above 14% reduced the feed cost (–18%; P<0.001), while inclusion above 21% improved net income (+32%; P<0.001). In conclusion, these results suggest that the use of dried brewers’ grains in diets for growing rabbits could improve the economic performance of the production system without impairing the animals’ performance.Lima, P.; Watanabe, P.; Cândido, R.; Ferreira, A.; Vieira, A.; Rodrigues, B.; Nascimento, G.... (2017). Dried brewers grains in growing rabbits: nutritional value and effects on performance. World Rabbit Science. 25(3):251-260. doi:10.4995/wrs.2017.6813.SWORD251260253Albuquerque, D. M. N., Lopes, J. B., Klein Junior, M. H., Merval, R. R., Silva, F. E. S., & Teixeira, M. P. F. (2011). Resíduo desidratado de cervejaria para suínos em terminação. Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 63(2), 465-472. doi:10.1590/s0102-09352011000200026AOAC International. 2005. Official methods of analysis of Association Official Analytical Chemists International. AOAC, Arlington VA. USA.Briganó, M. V., Pacheco, G. D., Bridi, A. M., Oba, A., Fonseca, N. A. N., & Silva, C. A. da. (2008). Desempenho e características de carcaça de suínos submetidos a diferentes programas de restrição alimentar na fase dos 30 aos 118 kg. Revista Brasileira de Zootecnia, 37(8), 1398-1404. doi:10.1590/s1516-35982008000800009De Blas, J. C., Rodriguez, C. A., Bacha, F., Fernandez, R., & Abad-Guamán, R. (2015). Nutritive value of co-products derived from olivecake in rabbit feeding. World Rabbit Science, 23(4), 255. doi:10.4995/wrs.2015.4036Etchu K.A., Humbu M.E., Ndamukong K.J.N., Agbor E.B. 2012. Effect of varying levels of brewers' dried grain on the growth performance of weaner rabbits (Oryctolagus Cuniculus). Greener J. Agric. Sci., 2: 237-245.Fazano A.R.T., Zinsly C.F., Mattos W.R.S., Packer I.H. 1986. Digestibilidade e valor biológico da proteína da levedura seca (Saccharomyces spp.) e do farelo de soja para coelhos. Boletim de Indústria Animal, 46: 185-191.Lounaouci-Ouyaed G., Lakabi-ioualitene D., Berchiche M., Lebas F. 2008. Field beans and brewers grain as protein source for growing rabbits in Algeria: first results on growth and carcass quality. Nutrition and Digestive Physiology. In: 9th World Rabbit Congress, June 10-13, Verona, Italy. 723-728.Matterson L.D., Potter L.M., Stutz M.W., Singsen E.P. 1965. The metabolizable energy of feed ingredients for chickens. Storrs: University of Connecticut; Agricultural Experiment Station Research Report, 11: 11.National Research Council. 2007. Nutrient requirements of small ruminants: sheep, goats, cervids, and New World camelids. Washington, D.C.: National Academic Press, 292.Partridge G., Wyatt C. 1995. More flexibility with new generation of enzymes. World Poultry,11: 17-21.SAS 2000. SAS/STAT User's Guide (Release 6.12). SAS Inst. Inc., Cary NC, EUA.Villamide, M. J. (1996). Methods of energy evaluation of feed ingredients for rabbits and their accuracy. Animal Feed Science and Technology, 57(3), 211-223. doi:10.1016/0377-8401(95)00855-

    Cosmological particle production, causal thermodynamics, and inflationary expansion

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    Combining the equivalence between cosmological particle creation and an effective viscous fluid pressure with the fact that the latter represents a dynamical degree of freedom within the second-order Israel-Stewart theory for imperfect fluids, we reconsider the possibility of accelerated expansion in fluid cosmology. We find an inherent self-limitation for the magnitude of an effective bulk pressure which is due to adiabatic (isentropic) particle production. For a production rate which depends quadratically on the Hubble rate we confirm the existence of solutions which describe a smooth transition from inflationary to noninflationary behavior and discuss their interpretation within the model of a decaying vacuum energy density. An alternative formulation of the effective imperfect fluid dynamics in terms of a minimally coupled scalar field is given. The corresponding potential is discussed and an entropy equivalent for the scalar field is found.Comment: 16 pages, revtex file, submitted to Phys. Rev.

    Macroscopic anisotropy in superconductors with anisotropic gaps

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    It is shown within the weak-coupling model that the macroscopic superconducting anisotropy for materials with the gap varying on the Fermi surface cannot be characterized by a single number, unlike the case of clean materials with isotropic gaps. For clean uniaxial materials, the anisotropy parameter γ(T)\gamma (T) defined as the ratio of London penetration depths, λc/λab\lambda_c/\lambda_{ab}, is evaluated for all TT's. Within the two-gap model of MgB2_2, γ(T)\gamma (T) is an increasing function of TT.Comment: 4 pages, 2 figure

    Critical flux pinning and enhanced upper-critical-field in magnesium diboride films

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    We have conducted pulsed transport measurements on c-axis oriented magnesium diboride films over the entire relevant ranges of magnetic field 0 \alt H \alt H_{c2} (where \hcu is the upper critical field) and current density 0 \alt j \alt j_{d} (where jdj_{d} is the depairing current density). The intrinsic disorder of the films combined with the large coherence length and three-dimensionality, compared to cuprate superconductors, results in a six-fold enhancement of Hc2H_{c2} and raises the depinning current density jcj_{c} to within an order of magnitude of jdj_{d}. The current-voltage response is highly non-linear at all fields, resulting from a combination of depinning and pair-breaking, and has no trace of an Ohmic free-flux-flow regime. Keywords: pair, breaking, depairing, superconductor, superconductivity, flux, fluxon, vortex, mgb

    Interaction in online postgraduate learning:What makes a good forum?

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    Online postgraduate courses for professionals often use discussion forums to promote engagement and interaction. Equivalency theorem suggests that student-student interaction may increase satisfaction but is not necessary for achieving desired learning outcomes. Therefore, costs, as well as benefits, should be ascertained. We used data from student feedback and interviews to assess the perceptions of part-time postgraduate distance learners, and analyze their views of the role, benefits, and drawbacks of discussion forums. The aim was to assess forum efficacy in the context of the specific needs of these learners, to inform forum use and design. Thematic analysis revealed complex interactions between student context and experience, forum design and management. Structurally tweaking forums to control engagement may be particularly ineffective, stimulating unhelpful grade-focused participation and highlighting forum opportunity costs. The study revealed the importance of designing and managing forums, with direct reference to their costs and benefits for specific student groups

    Irreversible Magnetization Under Rotating Fields And Lock-in Effect On A Erba2cu3o7-δ Single Crystal With Columnar Defects

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    We have measured the irreversible magnetization (Mi) of an ErBa2Cu3O7-δ single crystal with columnar defects (CD), using a technique based on sample rotation under a fixed magnetic field H. This method is valid for samples whose magnetization vector remains perpendicular to the sample surface over a wide angle range - which is the case for platelets and thin films - and presents several advantages over measurements of ML(H) loops at fixed angles. The resulting Mi(Θ) curves for several temperatures show a peak in the CD direction at high fields. At lower fields, a very well defined plateau indicative of the vortex lock-in to the CD develops. The H dependence of the lock-in angle ΦL follows the H-1 theoretical prediction, while the temperature dependence is in agreement with entropic smearing effects corresponding to long range vortex-defects interactions.641414450211445028Civale, L., Marwick, A.D., Worthington, T.K., Kirk, M.A., Thompson, J.R., Krusin-Elbaum, L., Sun, Y., Holtzberg, F., (1991) Phys. Rev. Lett., 67, p. 648Silhanek, A., Civale, L., Candia, S., Nieva, G., Pasquini, G., Lanza, H., (1999) Phys. Rev. B, 59, p. 13620Nelson, D.R., Vinokur, V.M., (1992) Phys. Rev. Lett., 68, p. 2398(1993) Phys. Rev. B, 48, p. 13060Blatter, G., Feigel'man, M.V., Geshkenbein, V.B., Larkin, A.I., Vinokur, V.M., (1994) Rev. Mod. Phys., 66, p. 1125Silhanek, A., Niebieskikwiat, D., Civale, L., Avila, M.A., Billoni, O., Casa, D., (1999) Phys. Rev. B, 60, p. 13189Avila, M.A., (2001), Ph. D. thesis, University of Campinas (UNICAMP), BrazilCandia, S., Civale, L., (1999) Supercond. Sci. Technol., 12, p. 192Clem, J.R., Sanchez, A., (1994) Phys. Rev. B, 50, p. 9355Prozorov, R., Poddar, A., Sheriff, E., Shaulov, A., Yeshurun, Y., (1996) Physica C, 264, p. 27Zhukov, A.A., Perkins, G.K., Bugoslavsky, Yu.V., Caplin, A.D., (1997) Phys. Rev. B, 56, p. 2809Hasanain, S.K., Ahmad, I., Semerad, R., (1999) Supercond. Sci. Technol., 12, p. 633Clem, J.R., (1982) Phys. Rev. B, 26, p. 2463Clem, J.R., Perez-Gonzalez, A., (1986) Phys. Rev. B, 33, p. 1601Perez-Gonzalez, A., Clem, J.R., (1990) Phys. Rev. B, 42, p. 4100Goeckner, H.P., Kouvel, J.S., (1994) Phys. Rev. B, 50, p. 3435Hasanain, S.K., Manzoor, S., Aftab, M., (1996) Physica C, 272, p. 43Hasan, M.K., Kouvel, J.S., (1997) Physica C, 276, p. 289Obaidat, I.M., Goeckner, H.P., Kouvel, J.S., (1997) Physica C, 291, p. 8Vlasko-Vlasov, V.K., Welp, U., Crabtree, G.W., Gunter, D., Kabanov, V.V., Nikitenko, V.I., Paulius, L.M., (1998) Phys. Rev. B, 58, p. 3446Obaidat, I.M., Park, S.J., Kouvel, J.S., (1998) Physica C, 308, p. 185Hasan, M.K., Shobaki, J., Al-Omari, I.A., Albiss, B.A., Al-Akhras, M.A., Azez, K.A., El-Qisari, A.K., Kouvel, J.S., (1999) Supercond. Sci. Technol., 12, p. 606Niebieskikwiat, D., Silhanek, A., Civale, Nieva, G., Levy, P., Krusin Elbaum, L., (2001) Phys. Rev. B, 63, p. 144504Krusin-Elbaum, L., Civale, L., Thompson, J.R., Feild, C., (1996) Phys. Rev. B, 53, p. 11744Civale, L., Pasquini, G., Levy, P., Nieva, G., Casa, D., Lanza, H., (1996) Physica C, 263, p. 389Zhukov, A.A., Perkins, G.K., Thomas, J.V., Caplin, A.D., Kupfer, H., Wolf, T., (1997) Phys. Rev. B, 56, p. 348

    Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors

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    Quasiclassic Uzadel equations for two-band superconductors in the dirty limit with the account of both intraband and interband scattering by nonmagnetic impurities are derived for any anisotropic Fermi surface. From these equations the Ginzburg-Landau equations, and the critical temperature TcT_c are obtained. An equation for the upper critical field, which determines both the temperature dependence of Hc2(T)H_{c2}(T) and the orientational dependence of Hc2(θ)H_{c2}(\theta) as a function of the angle θ\theta between H{\bf H} and the c-axis is obtained. It is shown that the shape of the Hc2(T)H_{c2}(T) curve essentially depends on the ratio of the intraband electron diffusivities D1D_1 and D1D_1, and can be very different from the standard one-gap dirty limit theory. In particular, the value Hc2(0)H_{c2}(0) can considerably exceed 0.7TcdHc2/dTc0.7T_cdH_{c2}/dT_c, which can have important consequences for applications of MgB2MgB_2. A scaling relation is proposed which enables one to obtain the angular dependence of Hc2(θ)H_{c2}(\theta) from the equation for Hc2H_{c2} at H∥c{\bf H}\| c. It is shown that, depending on the relation between D1D_1 and D2D_2, the ratio of the upper critical field Hc2∥/Hc2⊥H_{c2}^\|/H_{c2}^\perp for H∥ab{\bf H}\| ab and H⊥ab{\bf H}\perp ab can both increase and decrease as the temperature decreases. Implications of the obtained results for MgB2MgB_2 are discussed

    Nonlinear supersymmetry in Quantum Mechanics: algebraic properties and differential representation

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    We study the Nonlinear (Polynomial, N-fold,...) Supersymmetry algebra in one-dimensional QM. Its structure is determined by the type of conjugation operation (Hermitian conjugation or transposition) and described with the help of the Super-Hamiltonian projection on the zero-mode subspace of a supercharge. We show that the SUSY algebra with transposition symmetry is always polynomial in the Hamiltonian if supercharges represent differential operators of finite order. The appearance of the extended SUSY with several (complex or real) supercharges is analyzed in details and it is established that no more than two independent supercharges may generate a Nonlinear superalgebra which can be appropriately specified as {\cal N} = 2 SUSY. In this case we find a non-trivial hidden symmetry operator and rephrase it as a non-linear function of the Super-Hamiltonian on the physical state space. The full {\cal N} = 2 Non-linear SUSY algebra includes "central charges" both polynomial and non-polynomial (due to a symmetry operator) in the Super-Hamiltonian.Comment: 28 pages, Latex, minor improvements and removed misprint
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