7,395 research outputs found
Weyl geometry, anti-De Sitter space, and -theory
We study the Gaussian approximation to the quantum fluctuations of the metric
of the four dimensional anti-De Sitter spacetime. The associated massless
scalar field has a quartic self interaction, for which we construct the
generating functional of the -point correlation functions. The concomitant
infrared divergence is cured by a mass renormalization provided by the
cosmological constant, which is also responsible for the renormalization of the
coupling constant of the field theory.Comment: 9 pages, 1 figur
Employment generation in Brazilian coffee regions
Due to the specific characteristics of coffee production on each of the main Brazilian states producers of arabica (Coffea arabica) and robusta coffee (Coffea canephora), a better understanding of the structural links between production and industrialization of coffee on those states and the national economy can provide subsides for implementation of public policies, essential to plan the coffee production and increase the sector competitiveness. Therefore, this study analyzed the employment generation in production and coffee industrialization in the major Brazilian production regions, based on an inter-regional input-output model, with seven regions, which represent the main coffee-producing states - Minas Gerais, Espirito Santo, São Paulo, Paraná, Bahia and Other States - with 44 sectors each, in a system of 308 sectors. The results indicated that the production of robusta coffee is the sector that generates more employments (total) per currency unit, and that arabica production sector is the fourth largest generator of employments, among the 44 sectors considered for the country. The results for each state emphasized the importance of farming and coffee industry for national and state economies.Coffee; Coffee Production; Input-Output
Avaliação geral, resultados, perspectivas e uso de ferramentas de agricultura de precisão.
Resumo: A agricultura de Precisão aplica o conceito da espacialização ou da análise da variabilidade espacial dos fatores que influenciam a produção agropecuária. Dessa forma, a AP é bastante dependente de instrumentos que auxiliam na aquisição, tratamento e transmissão dos dados nos campos agrÃcolas, transformando-os em informações úteis para o manejo sÃtio especÃfico. Neste projeto componente estão sendo desenvolvidos e adaptados equipamentos, sensores, métodos, programas computacionais e uma plataforma de rede de sensores sem fio, denominadas de ferramentas de AP São apresentados resultados de equipamentos para a medida da matéria orgânica e umidade dos solos e de doenças de plantas; bancada de ensaios para a aplicação de insumos; esfera instrumentada para a avaliação de impactos no transporte de hortifrútis; modelagem, processamento de imagens e visão computacional; rede de sensores sem fio; robótica e projetos de sistemas embarcados para máquinas e implementos agrÃcolas. Participam deste Projeto Componente as seguintes Unidades da Embrapa e parceiros: Embrapa Instrumentação, Embrapa Informática, CSEM Brasil, Embrapa Pecuária Sudeste, Embrapa Pecuária Sul, Embrapa Trigo, Embrapa Hortaliças, Embrapa Florestas, Centro Internacional de la Papa (Peru) e membros da Força Tarefa ISOBUS
SP-Sephadex equilibrium chromatography of bradykinin and related peptides: Application to trypsin-treated human plasma
An analytical method is deseribed for the separation of bradykinin, Lys-bradykinin, and Met-Lys-bradykinin by equilibrium chromatography on SP-Sephadex C-25 eluted in 0.02 Tris-HCl buffer, pH 8.10, 0.12 NaCl. A second elution buffer, 0.02 Tris-HCl buffer, pH 7.70, 0.06 NaCl, serves as a second parameter for the identification of bradykinin and also separates the hormone from plasma bradykinin-potentiating peptides. Ten to one-hundred nanomoles of each peptide can be recovered in high yields, identified by elution position, and measured by bioassay with the isolated guinea pig ileum. The identification of bradykinin as the peptide released by trypsin acting on acid-denatured plasma is documented as an illustration of the method
Astrometry of mutual approximations between natural satellites. Application to the Galilean moons
Typically we can deliver astrometric positions of natural satellites with
errors in the 50-150 mas range. Apparent distances from mutual phenomena, have
much smaller errors, less than 10 mas. However, this method can only be applied
during the equinox of the planets. We developed a method that can provide
accurate astrometric data for natural satellites -- the mutual approximations.
The method can be applied when any two satellites pass close by each other in
the apparent sky plane. The fundamental parameter is the central instant
of the passage when the distances reach a minimum.
We applied the method for the Galilean moons. All observations were made with
a 0.6 m telescope with a narrow-band filter centred at 889 nm with width of 15
nm which attenuated Jupiter's scattered light. We obtained central instants for
14 mutual approximations observed in 2014-2015. We determined with an
average precision of 3.42 mas (10.43 km). For comparison, we also applied the
method for 5 occultations in the 2009 mutual phenomena campaign and for 22
occultations in the 2014-2015 campaign. The comparisons of determined by
our method with the results from mutual phenomena show an agreement by less
than 1-sigma error in , typically less than 10 mas. This new method is
particularly suitable for observations by small telescopes.Comment: 13 pages, 11 figures and 8 tables. Based on observations made at the
Laborat\'orio Nacional de Astrof\'isica (LNA), Itajub\'a-MG, Brazi
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The Importance of the Montreal Protocol in Mitigating the Potential Intensity of Tropical Cyclones
The impact of the Montreal Protocol on the potential intensity of tropical cyclones over the next 50 years is investigated with the Whole Atmosphere Community Climate Model (WACCM), a state-of-the-art, stratosphere-resolving atmospheric model, coupled to land, ocean, and sea ice components, with interactive stratospheric chemistry. An ensemble of WACCM runs from 2006 to 2065 forced with a standard future scenario is compared to a second ensemble in which ozone-depleting substances (ODS) are not regulated (the so-called World Avoided). It is found that by the year 2065, changes in the potential intensity of tropical cyclones in the World Avoided are nearly 3 times as large as for the standard scenario. The Montreal Protocol thus provides a strong mitigation of the adverse effects of intensifying tropical cyclones.
The relative importance of warmer sea surface temperatures (ozone-depleting substances are important greenhouse gases) and cooler lower-stratospheric temperatures (accompanying the massive destruction of the ozone layer) is carefully examined. It is found that the former are largely responsible for the increase in potential intensity in the World Avoided, whereas temperatures above the 70-hPa level—which plunge by nearly 15 K in 2065 in the World Avoided—have no discernible effect on potential intensity. This finding suggests that the modest (compared to the World Avoided) tropical ozone depletion of recent decades has not been a major player in determining the intensity of tropical cyclones, and neither will ozone recovery be in the coming half century
Stochastic magnetohydrodynamic turbulence in space dimensions
Interplay of kinematic and magnetic forcing in a model of a conducting fluid
with randomly driven magnetohydrodynamic equations has been studied in space
dimensions by means of the renormalization group. A perturbative
expansion scheme, parameters of which are the deviation of the spatial
dimension from two and the deviation of the exponent of the powerlike
correlation function of random forcing from its critical value, has been used
in one-loop approximation. Additional divergences have been taken into account
which arise at two dimensions and have been inconsistently treated in earlier
investigations of the model. It is shown that in spite of the additional
divergences the kinetic fixed point associated with the Kolmogorov scaling
regime remains stable for all space dimensions for rapidly enough
falling off correlations of the magnetic forcing. A scaling regime driven by
thermal fluctuations of the velocity field has been identified and analyzed.
The absence of a scaling regime near two dimensions driven by the fluctuations
of the magnetic field has been confirmed. A new renormalization scheme has been
put forward and numerically investigated to interpolate between the
expansion and the double expansion.Comment: 12 pages, 4 figure
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