114 research outputs found
On perfect fluid models in non-comoving observational spherical coordinates
We use null spherical (observational) coordinates to describe a class of
inhomogeneous cosmological models. The proposed cosmological construction is
based on the observer past null cone. A known difficulty in using inhomogeneous
models is that the null geodesic equation is not integrable in general. Our
choice of null coordinates solves the radial ingoing null geodesic by
construction. Furthermore, we use an approach where the velocity field is
uniquely calculated from the metric rather than put in by hand. Conveniently,
this allows us to explore models in a non-comoving frame of reference. In this
frame, we find that the velocity field has shear, acceleration and expansion
rate in general. We show that a comoving frame is not compatible with expanding
perfect fluid models in the coordinates proposed and dust models are simply not
possible. We describe the models in a non-comoving frame. We use the dust
models in a non-comoving frame to outline a fitting procedure.Comment: 8 pages, 1 figure. To appear in Phys.Rev.
Metabolic profile and histopathology of kidneys and liver of lambs fed silages of forages adapted to a semi-arid environment
Thirty-two mixed-breed ram lambs (average age, 5.6 ± 0.4 months, and average live weight, 17.61 ± 2.63 kg) were used to evaluate the effect of diets containing silages of forages adapted to a semi-arid environment on the metabolic profile in serum and the histopathological assessment of liver and kidney tissues of the lambs. Lambs were allocated, in a completely randomised design, to four treatments (silage of old man saltbush (Atriplex nummularia Lind), buffelgrass (Cenchrus ciliaris), gliricidia (Gliricidia sepium) and ‘pornunça’ (Manihot sp.). The feedlot period was 49 days, and animals were slaughtered at an average weight of 27 ± 4.6 kg. On the last day of the experiment, blood was collected from the jugular vein of all animals to measure the protein, metabolic and energy profiles of the lambs. At slaughter, kidney and liver samples were collected for histopathological examination. The consuming of the diet containing buffelgrass silage resulted in a significantly higher activity of alanine-aminotransferase (30.14 IU/L) and the concentrations of urea (44.25 mg/dL), creatinine (0.94 mg/dL) and albumin (4.48 g/dL) in serum. Diets containing gliricidia silage resulted in significantly higher gamma-glutamyl transferase activity (92.0 IU/L), while the diets with pornunça silage resulted in higher serum levels of triglycerides (37.85 mg/dL). The diets had no effect on aspartate-aminotransferase enzyme activity and total protein, cholesterol and globulin concentrations, or the albumin : globulin ratio in serum. Mild congestion, necrosis and foci of mineralisation were observed in the kidneys of animals fed diets containing old man saltbush (50%) and pornunça (25%) silages, and mild fatty degeneration and mild mononuclear inflammatory infiltrate in their livers. In conclusion, diets containing silages of forages that are adapted to semi-arid environments may be used for feeding lambs, given the absence of dysfunctioning plasmatic levels of liver enzymes and energy and protein profiles. Additionally, kidney failure was not observed in lambs fed these diets during the feedlot period.Keywords: blood parameters, buffelgrass, gliricidia, old man saltbush, pornunç
Síntese e caracterização de perovskitas do tipo LaNi1-xCu xO3 para a purificação de hidrogênio para PaCOS
Federalismo e políticas educacionais no Brasil: equalização e atuação do empresariado como projetos em disputa para a regulamentação do regime de colaboração
An assemblage of terrestrial isopods (Crustacea) in southern Brazil and its contribution to leaf litter processing
In vitro behaviour of Aspasia variegata, an epiphytic orchid from the Brazilian Cerrado
Climate change and future scenarios for palisade grass production in the state of São Paulo, Brazil
Ação anti-helmíntica de diferentes formulações de lactonas macrocíclicas em cepas resistentes de nematódeos de bovinos
Internal environmental conditions of soybean processing plants and safety in workplace
Cardiovascular responses to microinjections of GABA or anesthetics into the rostral ventrolateral medulla of conscious and anesthetized rats
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