518 research outputs found

    ln vivo prediction of body composition from the dilution space of the deuterium oxide in two lactating Spanish dairy breed ewes

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    Thirteen Churra (5 forty days and 8 seventy,days after lambing) and twelve Latxa (6 forty days and 6 a hundred and twenty days after lambing) lactating dairy ewes were used to obtain predicting equations of body fat, protein and energy from the live weight and the dilution space of deuterium oxide (SD20). Ewes were injected with 0.6 gD 20/kgo f live weight in the jugular vein and blood samples were collec5te, d7, 29 and 31 hours after infusion. The D20 content of blood water was determined by infrared spectrometry, and SDZO was calculated as the ratio between the weight of the injected D20 and its predicted concentration at zero time. After the last bleeding ewes were sheared and slaughtered and the body water, fat, protein, ash and energy were chemically determined. The Churra ewes presented 2% more water and 1.7% less protein in the fat free empty body 40 days than 70 days after lambing and fat free empty body water content decreased linearly (R=-0.60) with empty body fat content. There was however a close negative relationship (R2=0.97) between the fat and water content of the fleece free body weight. Neither the breed nor the stage of lactation significantly affect this relationship. Body water was predicted from SD20 with a residual standard deviation (RSD) of approximately kg when a pool equation was considered, though for a same SD20, the Latxa ewes presented 1.76 kg more water than the Churra ewes. Body fat and energy were predicted from the live weight and measured body water with a RSD of 0.437 kg and 6.85 Mcal, respectively, when a pool equation was considered. The adjusted means of body energy differed significantly between breeds and when this effect was taken into account the RSD diminished to 3.10 Mcal. When SDZO was substituted for measured body water, the resulting RSD were 0.980 kg and 6.85 Mcal, respectively. The intercept of the prediction equation of body fat differed significantly between breeds and when this effect was taken in account the RSD decreased to 0.703 kg. The accuracy of the body protein prediction from the ewes sheared body weight (RSD=0.56k9g from the pool equation and 0.282 kg for equation taking into account the breed effect) was not improved by the inclusion of SD20 as a second predictive variable. The stage of lactation did not significantly affect any of the equations studied

    La teología del trabajo en León XIII

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    Decay of the Sinai Well in D dimensions

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    We study the decay law of the Sinai Well in DD dimensions and relate the behavior of the decay law to internal distributions that characterize the dynamics of the system. We show that the long time tail of the decay is algebraic (1/t1/t), irrespective of the dimension DD.Comment: 14 pages, Figures available under request. Revtex. Submitted to Phys. Rev. E.,e-mail: [email protected]

    Wave scattering from self-affine surfaces

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    Electromagnetic wave scattering from a perfectly reflecting self-affine surface is considered. Within the framework of the Kirchhoff approximation, we show that the scattering cross section can be exactly written as a function of the scattering angle via a centered symmetric Levy distribution for general roughness amplitude, Hurst exponent and wavelength of the incident wave. The amplitude of the specular peak, its width and its position are discussed as well as the power law decrease (with scattering angle) of the scattering cross section.Comment: RevTeX, 4 pages including 2 figures. Submitted Phys. Rev. Let

    Mechanistic studies on the: N -alkylation of amines with alcohols catalysed by iridium(i) complexes with functionalised N-heterocyclic carbene ligands

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    Iridium(i) cyclooctadiene complexes featuring O- and N-donor functionalised NHC ligands efficiently catalyse the C-N coupling of amines with alcohols through a borrowing hydrogen mechanism. These catalysts have been applied for the N-alkylation of several aromatic and aliphatic primary amines with a range of alcohols including benzyl alcohol derivatives, straight-chain primary alcohols and secondary alcohols. The cationic complex [Ir(NCCH3)(cod){MeIm(2-methoxybenzyl)}]+ (cod = 1, 5-cyclooctadiene, MeIm = 3-methylimidazol-2-ylidene) having a rigid O-donor wingtip exhibits the best catalytic performance for the N-alkylation of aniline with benzyl alcohol giving a quantitative conversion to N-benzylaniline in 3 h. Experimental and theoretical studies at the DFT level on the N-alkylation of aniline with benzyl alcohol catalysed by the model compound [IrCl(cod)(IMe)] (IMe = 1, 3-dimethyl-imidazol-2-ylidene) support the participation of the iridium catalyst not only in the alcohol dehydrogenation and imine hydrogenation steps but also in the key step leading to the formation of the new C-N bond. Nucleophilic attack of an iridium-amido species generated in basic medium on the electrophilic aldehyde results in a hemiaminolate intermediate species from which the hemiaminal is released by alcoholysis. The free hemiaminal dehydrates to give the corresponding intermediate imine product that is hydrogenated by the iridium catalyst to the N-alkylated amine product. The iridium(i) complexes featuring functionalised NHC ligands are more active than [IrCl(cod)(IMe)] which highlights the positive influence of the functional group on the N-alkylation catalytic activity

    Biofunctionalized Polymer Nanomaterials: Implications on Shapes and Sizes

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    Nanotechnology has been one of the most widely used tools in various industries such as pharmaceutical, food, and chemistry, among others, for the encapsulation of compounds or even microorganisms. However, an analysis of the methodologies or polymer matrices to be used is rarely generated, and these in turn contribute to the objective of the product that is intended to be designed. In addition to the evaluation of its physicochemical, optical, and rheological characteristics, and others, are a set of technological tools that allow predicting the stability of a colloid, however, some of the factors that have less importance as the effect of the synthesis process on the shape and size that a structure may have, studies have been carried out to evaluate this phenomenon, which has become a determining factor in the design of any nanoscale material

    Electric field effects on magnetotransport properties of multiferroic Py/YMnO3/Pt heterostructures

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    We report on the exchange bias between antiferromagnetic and ferroelectric hexagonal YMnO3 epitaxial thin films sandwiched between a metallic electrode (Pt) and a soft ferromagnetic layer (Py). Anisotropic magnetoresistance measurements are performed to monitor the presence of an exchange bias field. When the heteroestructure is biased by an electric field, it turns out that the exchange bias field is suppressed. We discuss the dependence of the observed effect on the amplitude and polarity of the electric field. Particular attention is devoted to the role of current leakage across the ferroelectric layer.Comment: Accepted for publication in Philosophical Magazine Letters (Special issue on multiferroics

    Skin-associated lactic acid bacteria from North American bullfrogs as potential control agents of batrachochytrium dendrobatidis

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    The fungal pathogen Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis and has been a key driver in the catastrophic decline of amphibians globally. While many strategies have been proposed to mitigate Bd outbreaks, few have been successful. In recent years, the use of probiotic formulations that protect an amphibian host by killing or inhibiting Bd have shown promise as an effective chytridiomycosis control strategy. The North American bullfrog (Lithobates catesbeianus) is a common carrier of Bd and harbours a diverse skin microbiota that includes lactic acid bacteria (LAB), a microbial group containing species classified as safe and conferring host benefits. We investigated beneficial/probiotic properties: anti-Bd activity, and adhesion and colonisation characteristics (hydrophobicity, biofilm formation and exopolysaccharide-EPS production) in two confirmed LAB (cLAB-Enterococcus gallinarum CRL 1826, Lactococcus garvieae CRL 1828) and 60 presumptive LAB (pLAB) [together named as LABs] isolated from bullfrog skin.We challenged LABs against eight genetically diverse Bd isolates and found that 32% of the LABs inhibited at least one Bd isolate with varying rates of inhibition. Thus, we established a score of sensitivity from highest (BdGPL AVS7) to lowest (BdGPL C2A) for the studied Bd isolates. We further reveal key factors underlying host adhesion and colonisation of LABs. Specifically, 90.3% of LABs exhibited hydrophilic properties that may promote adhesion to the cutaneous mucus, with the remaining isolates (9.7%) being hydrophobic in nature with a surface polarity compatible with colonisation of acidic, basic or both substrate types. We also found that 59.7% of LABs showed EPS synthesis and 66.1% produced biofilm at different levels: 21% weak, 29% moderate, and 16.1% strong. Together all these properties enhance colonisation of the host surface (mucus or epithelial cells) and may confer protective benefits against Bd through competitive exclusion. Correspondence analysis indicated that biofilm synthesis was LABs specific with high aggregating bacteria correlating with strong biofilm producers, and EPS producers being correlated to negative biofilm producing LABs. We performed Random Amplified Polymorphic DNA (RAPD)-PCR analysis and demonstrated a higher degree of genetic diversity among rod-shaped pLAB than cocci. Based on the LAB genetic analysis and specific probiotic selection criteria that involve beneficial properties, we sequenced 16 pLAB which were identified as Pediococcus pentosaceus, Enterococcus thailandicus, Lactobacillus pentosus/L. plantarum, L. brevis, and L. curvatus. Compatibility assays performed with cLAB and the 16 species described above indicate that all tested LAB can be included in a mixed probiotic formula. Based on our analyses, we suggest that E. gallinarum CRL 1826, L. garvieae CRL 1828, and P. pentosaceus 15 and 18B represent optimal probiotic candidates for Bd control and mitigation. © 2019 Niederle et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited149FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2016/25358-3This research was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 063 to SEP), Consejo de Investigaciones de la Universidad Nacional de Tucumán (PIUNT 26/D 414 and 26/D 645 to SEP, and PIUNT 528), Agencia Nacional de Promoción Científica y Tecnológica (PICT 2017-2244 to SEP, PICT 2015-2467 to CEA, and PICT2017-4324 to MENM), Ministerio de Economía y Competitividad de España (CGL2015-70070-R to JB), Fondo Nacional de Desarrollo Científico y Tecnológico (1181758 to CSA and 3180107 to AVS), Fundação de Amparo à Pesquisa do Estado de São Paulo (2016/25358-3 to LFT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip
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