Electronic Phase Separation Transition as the Origin of the Superconductivity and the Pseudogap Phase of Cuprates

We propose a new phase of matter, an electronic phase separation transition that starts near the upper pseudogap and segregates the holes into high and low density domains. The Cahn-Hilliard approach is used to follow quantitatively this second order transition. The resulting grain boundary potential confines the charge in domains and favors the development of intragrain superconducting amplitudes. The zero resistivity transition arises only when the intergrain Josephson coupling $E_J$ is of the order of the thermal energy and phase locking among the superconducting grains takes place. We show that this approach explains the pseudogap and superconducting phases in a natural way and reproduces some recent scanning tunneling microscopy dataComment: 4 pages and 5 eps fig

Embryogenic responses of Vitis spp.: Effects of genotype and polyvinylpyrrolidone

Somatic embryos were obtained from leaf discs excised from cv. Seyve Villard 5276 (Vitis sp.) and from a Brazilian interspecific hybrid derived from Madalena (Vitis sp.) and Magnolia (V. rotundifolia). Experimental procedures were conducted according to HARST (1995) except that phenylalanine was replaced by polyvinylpyrrolidone which improved the embryogenic response of cultivar SV-5276. Standard somatic embryogenesis was confirmed by histological and ultrastructural analysis which also revealed teratological embryonic development. Secondary embryos were observed and documented by scanning microscop

Within Resting Period Seasonal Soluble Carbohydrate Profiles of Rotationally Grazed Elephant Grass

Recent evidence indicates that carbohydrate-rich grazed herbage is effective for improving milk production (Trevaskis et al., 2004). However, the dynamics of water-soluble carbohydrate (WSC) seasonal accumulation as related to forage availability remains unknown, especially during the growth stage of tropical forage grazing systems. The objective of the work was to verify the seasonal WSC profiles of rotationally grazed elephantgrass (Pennisetum purpureum Schum.), by making measurements within each 30-day resting period

Comportamento do coqueiro-anão-verde irrigado no Platô de Neólpolis.

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The Feasibility of Autoclave-Assisted Water Soluble Carbohydrate Extraction to Distinguish Annual Ryegrass Genotypes at the Seedling Stage

Annual ryegrass (Lolium multiflorum) swards are being used increasingly in Southern Brazil as animal forage (Carvalho et al., 2001). As observed elsewhere, reduced forage availability and quality during dry or cold seasons often limits the efficacy of pasture utilisation. As reported by Meissner et al. (1992), this demands breeding efforts to improve forage nutritive value. However, lack of concurrent examination of large number of samples for important nutritional parameters, like water-soluble carbohydrate (WSC) levels, which could lead to more precise selection strategies, is a common constraint of those programs. This study aimed to verify the suitability of using autoclave-assisted WSC extraction for concurrent screening of seedlings of annual ryegrass genotypes, aiming to establish early selection criteria

Parâmetros genéticos de características estimadas da curva de crescimento de ovinos da raça Santa Inês.

Resumo: Este trabalho foi realizado com os objetivos de estudar o ajuste das funções de Richards, Brody, Gompertz, Von Bertalanffy e Logística sobre a curva de crescimento de ovinos Santa Inês e estimar parâmetros genéticos para características calculadas a partir da função de melhor ajuste. Foram utilizadas apenas informações de fêmeas controladas entre os anos de 1993 e 2004, na Embrapa Tabuleiros Costeiros, e entre 1981 e 2004, na Embrapa Caprinos. Para o ajuste das curvas, as análises foram realizadas separadamente para cada rebanho, utilizando-se o procedimento NLIN do software Statistical Analysis System (SAS), por meio do método de GAUSS. Para determinar a função que melhor ajustava os dados, foram utilizados os critérios de coeficiente de determinação (R2), de quadrado médio residual (QMR) e o erro de predição médio (EM). No rebanho da Embrapa Tabuleiros Costeiros, todas as funções subestimaram os pesos, à exceção da curva de Richards. Diferentemente, todas as funções superestimaram o peso predito para o rebanho da Embrapa Caprinos. A curva de Richards foi a que promoveu melhor ajuste nos dois rebanhos. Os valores do peso adulto e da taxa de maturação estimados pela função de Richards foram de 54,38 kg e 0,00144/dia, respectivamente, para o rebanho da Embrapa Tabuleiros Costeiros, e 42,74 kg e 0,00260/dia, respectivamente, para o da Embrapa Caprinos. A função de Richards foi utilizada para estimar curvas individuais de crescimento dos animais. A partir destas curvas, foram estimadas várias características de interesse econômico. Os parâmetros genéticos e os componentes de (co) variância para estas características foram estimados pelo método da Máxima Verossimilhança Restrita Livre de Derivadas (DFREML), utilizando-se o software MTDFREML. As estimativas de herdabilidades direta e materna variaram, respectivamente, de 0,01 a 0,99 e de 0,00 a 0,13. É possível alterar o padrão da curva de crescimento destes animais por meio de seleção. Genetic parameters for traits estimated from the growth curve of Santa Inês hair sheep. Abstract: The aim of this work was to study the adjustment of Richards, Brody, Gompertz, Von Bertalanffy and Logistic functions on the growth curve of Santa Inês hair sheep and to estimate genetic parameters for the traits obtained from the best fitting function. Information from females of the Embrapa Tabuleiros Costeiros herd recorded between 1993 and 2004 and from the Embrapa Caprinos herd recorded between 1981 and 2004 was used. Functions were fitted for each herd, using NLIN procedure of Statistical Analysis System software (SAS), by GAUSS method. The coefficient of determination (R2), residual mean square (QMR) and mean prediction error (EM) were the criteria used to determine the best fitting function. For the Embrapa Tabuleiros Costeiros herd, all the functions subestimated the weights, except the Richards function. On the other hand, all the functions superestimated the weights of animals from the Embrapa Caprinos herd. The best fitting in the both herds was obtained using the Richards function. The respective values of mature weight and maturation rate estimated by Richards function were 54.38 kg and 0.00144/day for Embrapa Tabuleiros Costeiros herd and 42.74 kg and 0.00260/day for Embrapa Caprinos herd. The Richards function was used to estimate individual growth curves of animals in order to estimate genetic parameters and the (co)variance components for traits of economic importance using the Derivative Free Restricted Maximum Likelihood method (DFREML). The estimates of direct and maternal heritabilities ranged, respectively, from 0.01 to 0.99 and 0.00 to 0.13 suggesting the possibility of changing the growth curve of Santa Ines sheep by selection

Herding model and 1/f noise

We provide evidence that for some values of the parameters a simple agent based model, describing herding behavior, yields signals with 1/f power spectral density. We derive a non-linear stochastic differential equation for the ratio of number of agents and show, that it has the form proposed earlier for modeling of 1/f^beta noise with different exponents beta. The non-linear terms in the transition probabilities, quantifying the herding behavior, are crucial to the appearance of 1/f noise. Thus, the herding dynamics can be seen as a microscopic explanation of the proposed non-linear stochastic differential equations generating signals with 1/f^beta spectrum. We also consider the possible feedback of macroscopic state on microscopic transition probabilities strengthening the non-linearity of equations and providing more opportunities in the modeling of processes exhibiting power-law statistics

Landau Analog Levels for Dipoles in the Noncommutative Space and Phase Space

In the present contribution we investigate the Landau analog energy quantization for neutral particles, that possesses a nonzero permanent magnetic and electric dipole moments, in the presence of an homogeneous electric and magnetic external fields in the context of the noncommutative quantum mechanics. Also, we analyze the Landau--Aharonov--Casher and Landau--He--McKellar--Wilkens quantization due to noncommutative quantum dynamics of magnetic and electric dipoles in the presence of an external electric and magnetic fields and the energy spectrum and the eigenfunctions are obtained. Furthermore, we have analyzed Landau quantization analogs in the noncommutative phase space, and we obtain also the energy spectrum and the eigenfunctions in this context.Comment: 20 pages, references adde

Avaliação da curva de crescimento de ovinos da raça Santa Inês.

Este trabalho objetivou estudar o ajuste das funçoes Richards, Gompertz, Van Bertalanffy, Brody e Logistica sabre a curva de crescimento de ovinos da raça Santa Ines. Foram utilizados 20.403 pares de peso-idade de 498 femeas provenientes do rebanho da Embrapa Tabuleiros Costeiros e 2.699 pares de peso-idade de 294 femeas provenientes do rebanho da Embrapa Caprinos. Foram realizadas pesagens entre os anos de 1993 e 2004, com o minimo de dez pesagens por animal, para o rebanho da Embrapa Tabuleiros Costeiros e entre 1981 e 2004, com o minimo de cinco pesagens par animal, para o rebanho da Embrapa Caprinos. As analises foram realizadas separadamente para cada rebanho, utilizando-se o procedimento NLIN do pacote estatistico Statistical Analysis System (SAS), por meio do metodo de GAUSS. Para determinar a funçao de melhor ajuste para os dados, foram utilizados os criterios de coeficiente de determinaçao (R2), quadrado medio residual (QMR) e o erro de prediçao medio (EM). No rebanho da Embrapa Tabuleiros Costeiros, todas as funçoes subestimaram os pesos, com exceçao da curva de Richards. Diferentemente, todas as equaçoes superestimaram o peso predito para o rebanho da Embrapa Caprinos. Richards foi a curva que promoveu melhor ajuste nos dois rebanhos. Os valores do peso adulto e da taxa de maturaçao, estimados pela funçao de Richards, foram de 54,38 kg e 0,00144 /dia, respectivamente, para o rebanho da Embrapa Tabuleiros Costeiros, e 42,74 kg e 0,00260 /dia, respectivamente, para o rebanho da Embrapa Caprinos