Tensor Perturbations in Quantum Cosmological Backgrounds

In the description of the dynamics of tensor perturbations on a homogeneous and isotropic background cosmological model, it is well known that a simple Hamiltonian can be obtained if one assumes that the background metric satisfies Einstein classical field equations. This makes it possible to analyze the quantum evolution of the perturbations since their dynamics depends only on this classical background. In this paper, we show that this simple Hamiltonian can also be obtained from the Einstein-Hilbert lagrangian without making use of any assumption about the dynamics of the background metric. In particular, it can be used in situations where the background metric is also quantized, hence providing a substantial simplification over the direct approach originally developed by Halliwell and Hawking.Comment: 24 pages, JHEP forma

Correlator Bank Detection of GW chirps. False-Alarm Probability, Template Density and Thresholds: Behind and Beyond the Minimal-Match Issue

The general problem of computing the false-alarm rate vs. detection-threshold relationship for a bank of correlators is addressed, in the context of maximum-likelihood detection of gravitational waves, with specific reference to chirps from coalescing binary systems. Accurate (lower-bound) approximants for the cumulative distribution of the whole-bank supremum are deduced from a class of Bonferroni-type inequalities. The asymptotic properties of the cumulative distribution are obtained, in the limit where the number of correlators goes to infinity. The validity of numerical simulations made on small-size banks is extended to banks of any size, via a gaussian-correlation inequality. The result is used to estimate the optimum template density, yielding the best tradeoff between computational cost and detection efficiency, in terms of undetected potentially observable sources at a prescribed false-alarm level, for the simplest case of Newtonian chirps.Comment: submitted to Phys. Rev.

Casimir Energy For a Massive Dirac Field in One Spatial Dimension: A Direct Approach

In this paper we calculate the Casimir energy for a massive fermionic field confined between two points in one spatial dimension, with the MIT Bag Model boundary condition. We compute the Casimir energy directly by summing over the allowed modes. The method that we use is based on the Boyer's method, and there will be no need to resort to any analytic continuation techniques. We explicitly show the graph of the Casimir energy as a function of the distance between the points and the mass of the fermionic field. We also present a rigorous derivation of the MIT Bag Model boundary condition.Comment: 8 Pages, 4 Figure

QED vacuum between an unusual pair of plates

We consider the photon field between an unusual configuration of infinite parallel plates: a perfectly conducting plate $(\epsilon\to\infty)$ and an infinitely permeable one $\mu\to\infty)$. After quantizing the vector potential in the Coulomb gauge, we obtain explicit expressions for the vacuum expectation values of field operators of the form $_0$ and $<{\hat B}_i{\hat B}_j>_0$. These field correlators allow us to reobtain the Casimir effect for this set up and to discuss the light velocity shift caused by the presence of plates (Scharnhorst effect \cite{Scharnhorst,Barton,BarScharn}) for both scalar and spinor QED.Comment: Latex, 16 pages, no figure

Variação temporal da biomassa do café arábica arborizado e a pleno sol, através de índices de vegetação.

Abstract. In recent years, several works have been accomplished in order to analyze the spectral response of coffee crop fields cultivated in full sun. However, the number of papers related to the monitoring of shaded coffee systems is reduced although this kind of cultivation is very important from the perspective of climate change and agriculture. In addition, the biomass of coffee systems can store carbon, which is a mitigation action. In this context, this paper presents the assessment of the meteorological variation joined with the biomass increase in three different coffee plantation systems: full sun, shaded coffee associated with legumes (SAF), and shaded coffee with Macadamia trees. We used Landsat-5 images from 2004 to 2010, and the NDVI and SAVI indexes. LAI index measured in the test area during all 2009 year. The results showed that the shaded coffee systems presented the NDVI and SAVI indexes with higher values than those found with the system of planting in full sun what corroborates the idea of greater amount of biomass in this type of planting. All indexes present the seasonal rain variation. One month after a large period of drought the indexes NDVI, SAVI and LAI decrease. The NDVI and SAVI indexes presented high correlation with the measured LAI. The shaded coffee system and the full sun coffee reached high vegetation indexes what indicate a high concentration of biomass. This factor should be considered in the decision making process since is important to take advantage of cultivation systems acting as carbon sinks.SBSR 2011

How Many Templates for GW Chirp Detection? The Minimal-Match Issue Revisited

In a recent paper dealing with maximum likelihood detection of gravitational wave chirps from coalescing binaries with unknown parameters we introduced an accurate representation of the no-signal cumulative distribution of the supremum of the whole correlator bank. This result can be used to derive a refined estimate of the number of templates yielding the best tradeoff between detector's performance (in terms of lost signals among those potentially detectable) and computational burden.Comment: submitted to Class. Quantum Grav. Typing error in eq. (4.8) fixed; figure replaced in version

Sensory evaluation and cooking properties of macaroni at basis of brazil nut (Bertholetia excelsa) and peach palm fruit (Bactris gasipaes, Kunt) flours.

The Brazil nut tree, Bertholletia excelsa HBK, is explored throughout the Amazon region and its main characteristic is high content of lipids and proteins, they consist of sulfur amino acids of high biological value. The peach palm, Bactris gasipases, Kunth, is a native palm to the same region, that is grown for heart-of-palm extraction. Their fruits are mostly protein, vitamin A and fiber. The way of adding commercial value from co-products to Brazil nut processing is flour productian. That way the Brazil nut flour, for its high nutritional value and pleasant taste was used in macaroni production, along with peach palm fruit flour to improve the nutritianal properties of final product

Quantum Cosmology in Scalar-Tensor Theories With Non Minimal Coupling

Quantization in the minisuperspace of non minimal scalar-tensor theories leads to a partial differential equation which is non separable. Through a conformal transformation we can recast the Wheeler-DeWitt equation in an integrable form, which corresponds to the minimal coupling case, whose general solution is known. Performing the inverse conformal transformation in the solution so found, we can construct the corresponding one in the original frame. This procedure can also be employed with the bohmian trajectories. In this way, we can study the classical limit of some solutions of this quantum model. While the classical limit of these solutions occurs for small scale factors in the Einstein's frame, it happens for small values of the scalar field non minimally coupled to gravity in the Jordan's frame, which includes large scale factors.Comment: latex, 18 page

Inseminação artificial em caprinos leiteiros com sêmen resfriado por 24 ou 48 horas.

Resumo - Objetivou-se, avaliar a viabilidade da utilização do sêmen caprino diluído em meio tris-gema 2,5% resfriado a 5°C e armazenado por diferentes períodos (24 ou 48 horas). Foram inseminadas por via transcervical 133 cabras sem raça definida e nativas da República de Cabo Verde, divididas aleatoriamente em dois tratamentos T24 e T48. O estro foi sincronizado com a utilização de esponjas intra-vaginais contendo 60 mg de acetato de medroxiprogesterona por seis dias; 37,5 ?g de D-cloprostenol e 200 UI de eCG 24 horas antes da retirada da esponja. Foram utilizados três reprodutores da Raça Canárias. Para resfriar e manter o sêmen a 5o C foi utilizado o Botutainer® (Biotech Botucatu, Reprodução Animal, Botucatu - SP) adaptado. Não houve diferença (P > 0,05) entre os padrões seminais para os diferentes períodos de resfriamento (T24 - 58,8% ± 11,1 de motilidade e 2,9 ± 0,5 de vigor; T48 - 51,3% ± 2,5 de motilidade e 2,8 ± 0,3 de vigor), o que permitiu obter taxas de parição similares em ambos os tratamentos (T24 - 26,5% e T48 - 21,5%). A eficiência dos protocolos testados permitiu a disseminação de genética caprina na República de Cabo Verde. Conclui-se que o sêmen caprino, resfriado por 48 horas a 5ºC, tem o mesmo potencial de fertilização do sêmen resfriado por 24 horas a 5ºC. Artificial insemination in dairy goats with cooled semen stored for 24 or 48 hours. Abstract - The fertilizing capacity of goat semen diluted in tris-egg yolk 2.5% chilled at 5oC for 24 or 48 hours was evaluated. Transcervical artificial insemination was performed in 133 goats that were divided, randomly, into two treatments T24 and T48. The estrus was synchronized by the mean of intra-vaginal sponges containing 60 mg of medroxyprogesterone acetate for six days; 37.5 mg of D-cloprostenol and 200 IU of eCG, 24 hours before removing the sponge. Three Canarian?s Buck were used. For cooling and keeping the semen at 5oC a Botutainer® (Biotech Botucatu, Animal Reproduction, Botucatu - SP) was adapted and used. There was no difference (P > 0.05) between the seminal patterns for the different periods of cooling (T24 - 58.8%±11.1 for motility and 2.9±0.5 for strength; T48 - 51.3%±2.5 for motility and 2.8±0.3 for strength), which allowed to obtain similar pregnancy rates in both treatments (T24 ? 26.5% and T48 - 21,5%). The efficiency of the tested protocols allowed the dissemination of goat?s genetic material in the Republic of Cape Verde. It was concluded that goat semen, cooled for 48 hours at 5ºC, has the same fertility that semen cooled for 24 hours at 5ºC.Anais do 15o. Simpósio Paranaense de Ovinocultura, 3o. Simpósio Paranaense de Caprinocultura, 3o. Simpósio Sul Brasileiro de Ovinos e Caprinos, Pato Branco, PR, out., 2011

Possíveis impactos do projeto: "Uso de sêmen resfriado e inseminação artificial em caprinos leiteiros na República de Cabo Verde".

Resumo - Este artigo procura discutir o contexto do projeto ?Uso de sêmen resfriado e inseminação artificial em caprinos leiteiros na República de Cabo Verde?, suas implicações no sistema de criação de caprinos leiteiros, bem como seu impacto nos planos social, ambiental e econômico. Possible impacts of the project: "use of chilled semen and artificial insemination in dairy goats on Cape Verde Republic?. Abstract - This article intent to discuss the aspects involved in the project ?Use of chilled semen and artificial insemination in dairy goats on Cape Verde Republic? their implications on dairy goats rearing and also, the social, the economic, and the environmental impacts.Anais do 15o. Simpósio Paranaense de Ovinocultura, 3o. Simpósio Paranaense de Caprinocultura, 3o. Simpósio Sul Brasileiro de Ovinos e Caprinos, Pato Branco, PR, out., 2011