685 research outputs found
Higher-U(2,2)-spin fields and higher-dimensional W-gravities: quantum AdS space and radiation phenomena
A physical and geometrical interpretation of previously introduced tensor
operator algebras of U(2,2) in terms of algebras of higher-conformal-spin
quantum fields on the anti-de Sitter space AdS_5 is provided. These are
higher-dimensional W-like algebras and constitute a potential gauge guide
principle towards the formulation of induced conformal gravities
(Wess-Zumino-Witten-like models) in realistic dimensions. Some remarks on
quantum (Moyal) deformations are given and potentially tractable versions of
noncommutative AdS spaces are also sketched. The role of conformal symmetry in
the microscopic description of Unruh and Hawking's radiation effects is
discussed.Comment: LaTeX, 30 pages, 2 figures, final version to appear in Class. and
Quant. Gra
Thermal Vacuum Radiation in Spontaneously Broken Second-Quantized Theories on Curved Phase Spaces of Constant Curvature
We construct second-quantized (field) theories on coset spaces of
pseudo-unitary groups U(p,q)$. The existence of degenerated quantum vacua
(coherent states of zero modes) leads to a breakdown of the original
pseudo-unitary symmetry. The action of some spontaneously broken symmetry
transformations destabilize the vacuum and make it to radiate. We study the
structure of this thermal radiation for curved phase spaces of constant
curvature: complex projective spaces CP^{N-1}=SU(N)/U(N-1) and open complex
balls CD^{N-1}=SU(1,N-1)/U(N-1). Positive curvature is related to generalized
Fermi-Dirac (FD) statistics, whereas negative curvature is connected with
generalized Bose-Einstein (BE) statistics, the standard cases being recovered
for N=2. We also make some comments on the contribution of the vacuum (dark)
energy to the cosmological constant and the phenomenon of inflation.Comment: 17 pages. This article deals with a sort of "curvature-statistics
connection". To appear in Int. J. Geom. Meth. Mod. Phy
Structure Constants for New Infinite-Dimensional Lie Algebras of U(N+,N-) Tensor Operators and Applications
The structure constants for Moyal brackets of an infinite basis of functions
on the algebraic manifolds M of pseudo-unitary groups U(N_+,N_-) are provided.
They generalize the Virasoro and W_\infty algebras to higher dimensions. The
connection with volume-preserving diffeomorphisms on M, higher generalized-spin
and tensor operator algebras of U(N_+,N_-) is discussed. These
centrally-extended, infinite-dimensional Lie-algebras provide also the arena
for non-linear integrable field theories in higher dimensions, residual gauge
symmetries of higher-extended objects in the light-cone gauge and C^*-algebras
for tractable non-commutative versions of symmetric curved spaces.Comment: 8 pages, LaTeX, no figures; minor comments added; to appear in J.
Phys A (Math. Gen.
Evaluation of Guineagrass (\u3ci\u3ePanicum maximum\u3c/i\u3e Jacq) Hybrids in Brazil
Guineagrass (Panicum maximum Jacq.) is responsible for a high percentage of cattle finishing and milk production in Brazil, but presents problems of pasture degradability due to high soil fertility requirements and uneven production distribution. In order to search for new varieties to reduce these problems, over four hundred apomictic accessions of guineagrass and several sexual plants were introduced to Brazil in 1982. Agronomic evaluation took place at the National Beef Cattle Research Center of the Brazilian Agricultural Research Corporation (Embrapa Beef Cattle), in Campo Grande, MS, Brazil. Breeding of the apomictic species began in 1990 using sexual x apomictic crosses. Three sexual plants and five apomictic accessions were used in the crosses. Seventy-nine hybrids were evaluated in small plots, for forage yield, regrowth after cuts, flowering and vigor during three years. The best families were identified for each characteristic evaluated. Multivariate analysis using principal components grouped the hybrids into six clusters according to their production. Due to superior performance, hybrids in groups 6 and 2 (22 hybrids) were indicated for future regional trials in small plot evaluations and grazing studies, aiming at releasing new cultivars for pasture diversification in Brazil
Therapeutic intranasal vaccine HB-ATV-8 prevents atherogenesis and non-alcoholic fatty liver disease in a pig model of atherosclerosis
BACKGROUND AND AIMS: Atherosclerosis as an inflammatory disease involved in the etiology of cardiovascular disease worldwide, in our days demands an array of different therapeutic approaches in order to soon be able to visualize an effective prevention. Based on an immunotherapeutic approach, we designed a non-invasive vaccine (HB-ATV-8), contained in a micellar nanoparticle composed of lipids and a peptide segment derived from the C-terminus of the cholesterol-ester transfer protein (CETP). Now we extend our successful proof of concept from the rabbit to a porcine model and investigated its effect in an attempt to undoubtedly establish the efficacy of vaccination in a model closer to the human. METHODS: A preclinical trial was designed to study the efficacy of vaccine HB-ATV-8 in pigs (Large White × Landrace). Male experimental animals were fed with standard diet (control), high fat diet (HFD) or the same HFD but treated with HB-ATV-8 (HFD + Vaccine) applied nasally for up to 7 months. All biochemical and enzymatic analyses were performed in peripheral venous blood and thoracic aorta and liver samples examined using conventional, two-photon excitation and second harmonic generation microscopy to identify atherosclerotic and hepatic lesions. mRNA concentrations for KLF2, ACTA2, SOD1, COL1A1 genes and protein levels for PPARα and ABCA1 were quantified in aorta and liver respectively using qPCR and Western blot analysis. RESULTS: The administration of vaccine HB-ATV-8 induced anti-CETP IgG antibodies and reduced atherosclerotic and hepatic lesions promoted by the high fat diet. In addition, plasma triglyceride levels of vaccine treated pigs fed the HFD were similar to those of control group, in contrast to high concentrations reached with animals exclusively fed with HFD. Moreover, HFD promotes a tendency to decreased hepatic PPARα levels and increase in aorta gene expression of KLF2, ACTA2, SOD1 and COL1A1, while vaccine application promotes recovery close to control values. CONCLUSIONS: Vaccine HB-ATV-8 administration constitutes a promissory preventive approach useful in the control of atherogenesis and fatty liver disease. The positive results obtained, the non-invasive characteristics of the vaccine, the simple design employed in its conception and its low production cost, support the novelty of this therapeutic strategy designed to prevent the process of atherogenesis and control the development of fatty liver disease
Bioactive compounds and antioxidant capacities of 18 non-traditional tropical fruits from Brazil.
Metodologia científica: determinação da atividade antioxidante total em frutas pela captura do radical livre DPPH.
bitstream/CNPAT/10224/1/Cot_127.pd
Metodologia científica: determinação da atividade antioxidante total em frutas pelo método de redução do ferro (FRAP)
bitstream/CNPAT-2010/11964/1/cot-125.pd
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