548 research outputs found

    Reddening, Absorption, and Decline Rate Corrections for a Complete Sample of Type Ia Supernovae leading to a Fully Corrected Hubble Diagram to v<30,000kms-1

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    Photometric BVI and redshift data corrected for streaming motions are compiled for 111 "Branch normal", 4 1991T-like, 7 1991bg-like, and 2 unusual SNe Ia. Color excesses E(B-V)host of normal SNe Ia, due to the absorption of the host galaxy, are derived by three independent methods leading to the intrinsic colors at maximum of (B-V)00=-0.024, and (V-I)00=-0.265 if normalized to a common decline rate of Dm_15=1.1. The strong correlation between redshift absolute magnitudes (based on Ho=60), corrected only for the extrinsic Galactic absorption, and the derived E(B-V)host leads to well determined, yet abnormal absorption-to-reddening ratios of R_BVI=3.65, 2.65, and 1.35. Comparison with the canonical Galactic values of 4.1, 3.1, 1.8 forces the conclusion that the law of interstellar absorption in the path length to the SN in the host galaxy is different from the local Galactic law. Improved correlations of the fully corrected absolute magnitudes with host galaxy type, decline rate, and intrinsic color are derived. The four peculiar 1991T-type SNe are significantly overluminous as compared to Branch-normal SNe Ia. The overluminosity of the seven 1999aa-like SNe is less pronounced. The seven 1991bg-types in the sample constitute a separate class of SNeIa, averaging in B two magnitudes fainter than the normal Ia. New Hubble diagrams in BVI are derived out to ~30,000kms-1 using the fully corrected magnitudes and velocities, corrected for streaming motions. Nine solutions for the intercept magnitudes in these diagrams show extreme stability at the 0.04 level using various subsamples of the data. The same precepts for fully correcting SN magnitudes we shall use for the luminosity recalibration of SNe Ia in the forthcoming final review of our HST Cepheid-SN experiment for the Hubble constant.Comment: 49 pages, 15 figures, 8 tables, accepted for publication in the Astrophysical Journa

    Adding diphenyl diselenide in the diets of quails improves the quality of meat.

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    Abstract: Diphenyl diselenide (Ph2Se2) is an organic selenium compound that is known for its antioxidant characteristics. Thus, the aim of this study was to evaluate whether Ph2Se2 in quail (Coturnix japonica) diets influences the oxidative/antioxidant status and meat quality. Materials and methods. Four diets (0; 0.3; 0.6; 0.9 ppm Ph2Se2) were provided to 56 male quails (Coturnix japonica) distributed in a completely randomized design with 14 repetitions in order to check whether (PhSe)2 would change their blood and tissue oxidative/antioxidant status, which would lead to an improvement in the meat quality. Results. Adding Ph2Se2 in diets led to increased antioxidant activity of enzymes such as catalase, superoxide dismutase, and glutathione peroxidase, which consequently reduced oxidative levels in blood and tissues. Besides that, we observed an improvement in the quail meat quality; in other words, we observed an increased ability to hold water, a reduction in water loss from cooking, and reduced intensity of the yellow color in the breasts of birds that were fed with Ph2Se2. Conclusions. Therefore, we concluded that the antioxidant defense improvement in tissues that was provided by Ph2Se2 has a beneficial effect on meat quality. Resumen: El diseleniuro de difenilo (Ph2Se2) es un compuesto de selenio orgánico que es conocido por sus características antioxidantes. Por lo tanto, el objetivo de este estudio fue evaluar si Ph2Se2 en las dietas de codorniz (Coturnix japonica) influye en el estado oxidativo/antioxidante y la calidad de la carne. Materiales y métodos. Se proporcionaron cuatro dietas (0; 0.3; 0.6; 0.9 ppm Ph2Se2) a 56 codornices machos (Coturnix japonica) distribuidas en un diseño completamente aleatorizado con 14 repeticiones para verificar si Ph2Se2 cambiaría su sangre y tejido oxidativo/antioxidante, estado, lo que llevaría a una mejora en la calidad de la carne. Resultados. La adición de Ph2Se2 en las dietas provocó un aumento de la actividad antioxidante de enzimas como la catalasa, la superóxido dismutasa y la glutatión peroxidasa, lo que redujo los niveles de oxidación en la sangre y los tejidos. Además de eso, observamos una mejora en la calidad de la carne de codorniz; en otras palabras, observamos una mayor capacidad para retener agua, una reducción en la pérdida de agua debido a la cocción y una menor intensidad del color amarillo en las mamas de las aves que fueron alimentadas con Ph2Se2. Conclusiones. Por lo tanto, concluimos que la mejora de la defensa antioxidante en los tejidos proporcionada por Ph2Se2 tiene un efecto beneficioso sobre la calidad de la carne

    Lysozyme affects the microbial catabolism of free arginine in raw-milk hard cheeses

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    Lysozyme (LZ) is used in several cheese varieties to prevent late blowing which results from fermentation of lactate by Clostridium tyrobutyricum. Side effects of LZ on lactic acid bacteria population and free amino acid pattern were studied in 16 raw-milk hard cheeses produced in eight parallel cheese makings conducted at four different dairies using the same milk with (LZ\ufe) or without (LZ-) addition of LZ. The LZ-cheeses were characterized by higher numbers of cultivable microbial population and lower amount of DNA arising from lysed bacterial cells with respect to LZ \ufe cheeses. At both 9 and 16 months of ripening, Lactobacillus delbrueckii and Lactobacillus fermentum proved to be the species mostly affected by LZ. The total content of free amino acids indicated the proteolysis extent to be characteristic of the dairy, regardless to the presence of LZ. In contrast, the relative patterns showed the microbial degradation of arginine to be promoted in LZ \ufe cheeses. The data demonstrated that the arginine-deiminase pathway was only partially adopted since citrulline represented the main product and only trace levels of ornithine were found. Differences in arginine degradation were considered for starter and non-starter lactic acid bacteria, at different cheese ripening stages

    Interacting Preformed Cooper Pairs in Resonant Fermi Gases

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    We consider the normal phase of a strongly interacting Fermi gas, which can have either an equal or an unequal number of atoms in its two accessible spin states. Due to the unitarity-limited attractive interaction between particles with different spin, noncondensed Cooper pairs are formed. The starting point in treating preformed pairs is the Nozi\`{e}res-Schmitt-Rink (NSR) theory, which approximates the pairs as being noninteracting. Here, we consider the effects of the interactions between the Cooper pairs in a Wilsonian renormalization-group scheme. Starting from the exact bosonic action for the pairs, we calculate the Cooper-pair self-energy by combining the NSR formalism with the Wilsonian approach. We compare our findings with the recent experiments by Harikoshi {\it et al.} [Science {\bf 327}, 442 (2010)] and Nascimb\`{e}ne {\it et al.} [Nature {\bf 463}, 1057 (2010)], and find very good agreement. We also make predictions for the population-imbalanced case, that can be tested in experiments.Comment: 10 pages, 6 figures, accepted version for PRA, discussion of the imbalanced Fermi gas added, new figure and references adde
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