Exactly Solvable Models of Interacting Spin-s Particles in one-dimension

We consider the exact solution of a many-body problem of spin-$s$ particles interacting through an arbitrary U(1) invariant factorizable $S$-matrix. The solution is based on a unified formulation of the quantum inverse scattering method for an arbitrary $(2s+1)$-dimensional monodromy matrix. The respective eigenstates are shown to be given in terms of $2s$ creation fields by a general new recurrence relation. This allows us to derive the spectrum and the respective Bethe ansatz equations.Comment: 10 pages, plain late

Evidence for a spectroscopic direct detection of reflected light from 51 Peg b

The detection of reflected light from an exoplanet is a difficult technical challenge at optical wavelengths. Even though this signal is expected to replicate the stellar signal, not only is it several orders of magnitude fainter, but it is also hidden among the stellar noise. We apply a variant of the cross-correlation technique to HARPS observations of 51 Peg to detect the reflected signal from planet 51 Peg b. Our method makes use of the cross-correlation function of a binary mask with high-resolution spectra to amplify the minute planetary signal that is present in the spectra by a factor proportional to the number of spectral lines when performing the cross correlation. The resulting cross-correlation functions are then normalized by a stellar template to remove the stellar signal. Carefully selected sections of the resulting normalized CCFs are stacked to increase the planetary signal further. The recovered signal allows probing several of the planetary properties, including its real mass and albedo. We detect evidence for the reflected signal from planet 51 Peg b at a significance of 3\sigma_noise. The detection of the signal permits us to infer a real mass of 0.46^+0.06_-0.01 M_Jup (assuming a stellar mass of 1.04\;M_Sun) for the planet and an orbital inclination of 80^+10_-19 degrees. The analysis of the data also allows us to infer a tentative value for the (radius-dependent) geometric albedo of the planet. The results suggest that 51Peg b may be an inflated hot Jupiter with a high albedo (e.g., an albedo of 0.5 yields a radius of 1.9 \pm 0.3 R_Jup for a signal amplitude of 6.0\pm0.4 x 10^-5). We confirm that the method we perfected can be used to retrieve an exoplanet's reflected signal, even with current observing facilities. The advent of next generation of observing facilities will yield new opportunities for this type of technique to probe deeper into exoplanets.Comment: 9 pages, 6 figure

Seleção de populações segregantes de feijoeiro-comum carioca com altos teores de ferro e zinco.

O objetivo deste trabalho foi obter genitores e populações segregantes de feijoeiro-comum com potencial para altos teores de ferro e zinco.CONAF

Interação genótipos x ambientes para teores de ferro e zinco nos grãos de feijoeiro-comum.

Os objetivos do presente trabalho foram estudar o efeito da interação GxA para teor de ferro e teor de zinco no grão; selecionar linhagens com maiores teores desses minerais e identificar se existe relação entre esses caracteres.CONAF

Identificação de linhagens elite de feijoeiro-comum com altos teores de ferro e zinco nos grãos.

Este trabalho teve por objetivo selecionar entre linhagens elite de feijão carioca, aquelas com maiores teores de ferro e zinco nos grãos para realização de novos cruzamentos visando o aumento dos teores desses minerais, bem como estimar parâmetros genéticos para esses caracteres. Para isto foram avaliadas 68 linhagens em campo em Santo Antônio de Goiás na época do inverno em 2011

Caracterização de progênie híbrida de cajueiro-anão precoce quanto à infeccção de Lasiodiplodia theobromae.

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Monitoring the thermal efficiency of fouled heat exchangers: A simplified method

Fouling is a problem whether we are aware of it or not. In an industrial plant, it is important not only to be able to measure the buildup of unwanted deposits, but also to do it in the simplest and most economically possible way. This paper addresses the question of monitoring fouling in an oil refinery plant, where the high number of heat exchanger units and the variability of the feedstock charge pose additional problems in terms of the practicability of following the energetic performance of such equipment. In this case, the flow rates and quality of the fluids flowing through the heat exchangers do not usually correspond to the design conditions, because they change with time. Therefore, to assess the fouling level of the exchangers, the day-to-day measured thermal efficiency should not be compared with the efficiency predicted in the design calculations. The latter should be recalculated by introducing whenever necessary new values of flow rates, physical properties, and so forth, and by evaluating new heat transfer coefficients. However, the procedures are too time consuming to be applied frequently. The present work describes a simplified method for following heat exchanger performances, based on the assessment of the number of transfer units and thermal efficiencies, where the effects of changing the feedstock charge, particularly the flow rates of the fluids, are taken into account. The only data that need to be collected are the four inlet/outlet temperatures of the heat exchanger unit and one of the flow rates. Several heat exchanger units in an oil refinery were successfully monitored by means of this method, and it was found that the variations in the physical properties did not significantly affect the results obtained for the particular plant under study