113 resultados para gravity anomaly


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Using 2-body trees on a flat space background, it is shown that the actions A[g, φ] = (Latin small letter esh) d4x√-g [(R/2K) + (1/2)(gμν ∂μφ∂νφ + λRφ2)] and Ā[ḡ, φ̄] = (Latin small letter esh) d4x√ - ḡ [(R̄/2k) + (1/2) ḡμν∂μφ̄∂ νφ] describe the same theory at the tree-level in this case. We also demonstrate the quantum equivalence (at one-loop) of the barred and unbarred systems for λ == -1/6 (conformal coupling).

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We calculate within the framework of relativistic nuclear models the contribution of the ρ0 - ω mixing interaction to the binding energy differences of the mirror nuclei in the neighborhood of A = 16 and A = 40. We use two relativistic models for the nuclear structure, one with scalar and vector Woods-Saxon potentials, and the Walecka model. The ρ0 - ω interaction is treated in first order perturbation theory. When using the Walecka model the ρ- and ω-nucleon coupling constants are the same for calculating bound state wave functions and the perturbation due to the mixing. We find that the relativistic results on the average are of the same order as the ones obtained with nonrelativistic calculations.

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Starting out with an anomaly free lagrangian formulation for chiral scalars, which includes a Wess-Zumino term (to cancel the anomaly), we formulate the corresponding hamiltonian problem. Then we use the (quantum) Siegel invariance to choose a particular solution, which turns out to coincide with the one obtained by Floreanini and Jackiw. © 1988.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Indicine cattle have lower reproductive performance in comparison to taurine. A chromosomal anomaly characterized by the presence Y markers in females was reported and associated with infertility in cattle. The aim of this study was to investigate the occurrence of the anomaly in Brahman cows. Brahman cows (n = 929) were genotyped for a Y chromosome specific region using real time-PCR. Only six out of 929 cows had the anomaly (0.6%). The anomaly frequency was much lower in Brahman cows than in the crossbred population, in which it was first detected. It also seems that the anomaly doesn't affect pregnancy in the population. Due to the low frequency, association analyses couldn't be executed. Further, SNP signal of the pseudoautosomal boundary region of the Y chromosome was investigated using HD SNP chip. Pooled DNA of non-pregnant and pregnant cows were compared and no difference in SNP allele frequency was observed. Results suggest that the anomaly had a very low frequency in this Australian Brahman population and had no effect on reproduction. Further studies comparing pregnant cows and cows that failed to conceive should be executed after better assembly and annotation of the Y chromosome in cattle.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The Guapiara Lineament is an important geological feature of the State of São Paulo, Brazil, associated with Mesozoic volcanism in the Paraná Basin. This paper aims at the interpretation and modeling of gravity data collected at a semi-detailed scale between Capão Bonito and Apiaí to identify the geometry of crustal partitioning along this lineament. Maps of Bouguer anomaly in the area show a remarkable positive gravimetric anomaly oriented NW-SE, which coincides with the orientation of the greater concentration of dikes associated with the Guapiara Lineament. The crustal model developed from anomalies shows a significant thinning of the crust in the area and corroborates previous studies. The crustal thinning was caused by mantle rise, reflecting the epirogenetic activity generated by the propagation of the divergent tectonic forces that occurred at the margin of the South American Plate during the Cretaceous.