The anisotropic XY model on the inhomogeneous periodic chain

The static and dynamic properties of the anisotropic XY-model $(s=1/2)$ on the inhomogeneous periodic chain, composed of $N$ cells with $n$ different exchange interactions and magnetic moments, in a transverse field $h,$ are determined exactly at arbitrary temperatures. The properties are obtained by introducing the Jordan-Wigner fermionization and by reducing the problem to a diagonalization of a finite matrix of $nth$ order. The quantum transitions are determined exactly by analyzing, as a function of the field, the induced magnetization 1/n\sum_{m=1}^{n}\mu_{m}\left ($j$ denotes the cell, $m$ the site within the cell, $\mu_{m}$ the magnetic moment at site $m$ within the cell) and the spontaneous magnetization $1/n\sum_{m=1}^{n}\left< S_{j,m}^{x},\right>$ which is obtained from the correlations $\left< S_{j,m}^{x}S_{j+r,m}^{x}\right>$ for large spin separations. These results, which are obtained for infinite chains, correspond to an extension of the ones obtained by Tong and Zhong(\textit{Physica B} \textbf{304,}91 (2001)). The dynamic correlations, $\left< S_{j,m}^{z}(t)S_{j^{\prime},m^{\prime}}^{z}(0)\right>$, and the dynamic susceptibility, $\chi_{q}^{zz}(\omega),$ are also obtained at arbitrary temperatures. Explicit results are presented in the limit T=0, where the critical behaviour occurs, for the static susceptibility $\chi_{q}^{zz}(0)$ as a function of the transverse field $h$, and for the frequency dependency of dynamic susceptibility $\chi_{q}^{zz}(\omega)$.Comment: 33 pages, 13 figures, 01 table. Revised version (minor corrections) accepted for publiction in Phys. Rev.

Crossover to the KPZ equation

We characterize the crossover regime to the KPZ equation for a class of one-dimensional weakly asymmetric exclusion processes. The crossover depends on the strength asymmetry $an^{2-\gamma}$ ($a,\gamma>0$) and it occurs at $\gamma=1/2$. We show that the density field is a solution of an Ornstein-Uhlenbeck equation if $\gamma\in(1/2,1]$, while for $\gamma=1/2$ it is an energy solution of the KPZ equation. The corresponding crossover for the current of particles is readily obtained.Comment: Published by Annales Henri Poincare Volume 13, Number 4 (2012), 813-82

A network landscape from CNVs to Nellore cattle beef tenderness.

This work aims to perform a couple of in silico network analysis from CNVs standpoint, shedding light to possible metabolic connections to tenderness. It was used 671 Nellore males to infer CNVs, through SNP-chip (Illumina Bovine HD Beadchip®, containing approximately 770 thousand SNPs) and PennCNV software methodology. CNV regions (CNVRs) were inferred by CNVRuler (recurrence 0.1).ISAFG 2013. AB.01

A network landscape from CNVs to Nellore cattle beef tenderness.

This work aims to perform a couple of in silico network analysis from CNVs standpoint, shedding light to possible metabolic connections to tenderness. It was used 671 Nellore males to infer CNVs, through SNP-chip (Illumina Bovine HD Beadchip®, containing approximately 770 thousand SNPs) and PennCNV software methodology. CNV regions (CNVRs) were inferred by CNVRuler (recurrence 0.1).ISAFG 2013. AB.01

Modeling of Mechanosensing Mechanisms Reveals Distinct Cell Migration Modes to Emerge From Combinations of Substrate Stiffness and Adhesion Receptor–Ligand Affinity

Mesenchymal cell migration is an integral process in development and healing. The process is regulated by both mechanical and biochemical properties. Mechanical properties of the environment are sensed through mechanosensing, which consists of molecular responses mediated by mechanical signals. We developed a computational model of a deformable 3D cell on a flat substrate using discrete element modeling. The cell is polarized in a single direction and thus moves along the long axis of the substrate. By modeling discrete focal adhesions and stress fibers, we implement two mechanosensing mechanisms: focal adhesion stabilization by force and stress fiber strengthening upon contraction stalling. Two substrate-associated properties, substrate (ligand) stiffness and adhesion receptor–ligand affinity (in the form of focal adhesion disassembly rate), were varied for different model setups in which the mechanosensing mechanisms are set as active or inactive. Cell displacement, focal adhesion number, and cellular traction were quantified and tracked in time. We found that varying substrate stiffness (a mechanical property) and adhesion receptor–ligand affinity (a biochemical property) simultaneously dictate the mode in which cells migrate; cells either move in a smooth manner reminiscent of keratocytes or in a cyclical manner reminiscent of epithelial cells. Mechanosensing mechanisms are responsible for the range of conditions in which a cell adopts a particular migration mode. Stress fiber strengthening, specifically, is responsible for cyclical migration due to build-up of enough force to elicit rupture of focal adhesions and retraction of the cellular rear. Together, both mechanisms explain bimodal dependence of cell migration on substrate stiffness observed in the literature

Parâmetros hematológicos de pacu (Piaractus mesopotamicus) alimentados com glúten de milho.

Resumo: O objetivo deste estudo foi avaliar os parâmetros sanguíneos de juvenis de pacu alimentados com glúten de milho. Foram utilizados 100 juvenis de pacu, com peso médio inicial de 32,79 ± 3,43 g, distribuídos em vinte gaiolas com volume aproximado de 70 L cada, alojadas em cinco tanques circulares de 1000 L em sistema com renovação continua de água proveniente de poço artesiano, durante 60 dias. O delineamento experimental foi inteiramente casualizado com cinco tratamentos 0; 25; 50; 75 e 100 % de substituição da proteína do farelo de soja pela proteína do glúten de milho, que correspondeu a 6,12; 12,24; 18,36 e 24,49 % de inclusão de glúten na ração e quatro repetições. No final do experimento foi coletado sangue (1,0 mL) de doze peixes de cada tratamento para determinação do hematócrito, proteína plasmática total, hemoglobina, eritrócitos, volume corpuscular médio e concentração de hemoglobina corpuscular média. Para avaliação dos dados foi aplicado à análise de variância e teste de Tukey a 5% de significância. Não houve diferença (P>0,05) entre os tratamentos analisados. Pode-se concluir que a substituição de até 100 % (24,49 % de inclusão na ração) da proteína de soja pela proteína do glúten de milho não altera os parâmetros hematológicos de juvenis de pacu

Hydrodynamic limit for weakly asymmetric simple exclusion processes in crystal lattices

We investigate the hydrodynamic limit for weakly asymmetric simple exclusion processes in crystal lattices. We construct a suitable scaling limit by using a discrete harmonic map. As we shall observe, the quasi-linear parabolic equation in the limit is defined on a flat torus and depends on both the local structure of the crystal lattice and the discrete harmonic map. We formulate the local ergodic theorem on the crystal lattice by introducing the notion of local function bundle, which is a family of local functions on the configuration space. The ideas and methods are taken from the discrete geometric analysis to these problems. Results we obtain are extensions of ones by Kipnis, Olla and Varadhan to crystal lattices.Comment: 41 pages, 7 figure

Silicon nitride thin-films by RF sputtering : application on solid state lithium batteries

Silicon nitride is the most common barrier material to protect microsystems from atmosphere, usually deposited through CVD techniques. In this paper our aim is to highlight the advantages brought by using PVD techniques, namely RF sputtering, to deposit silicon nitride thin-films. In particular, we intend to protect microsystems fabricated only by PVD techniques and avoid the necessity of a second CVD chamber to do the microsystem coating. The influence of gases (Ar/N2) during deposition was correlated with film composition and with measured electrical and optical properties. Featuring electric resistivity of 9.51E11 Ω.cm, a breakdown field of 1.67 MV/cm and refractive index between 1.92 and 1.84 (measured at 650 nm) silicon nitride deposited by RF sputtering is a good complementary layer of Li3PO4 or Ti for the protection of metallic lithium anode of solid state lithium batteries.This work was financial supported by FCT funds with the project PTDC/EEAELC/114713/2009, second author scholarship SFRH/BD/78217/2011 and strategic project from Algoritmi Centre FCOMP-01-0124-FEDER-02267

Ganhos genéticos com a seleção para caráter rendimento de polpa por fruto em açaizeiro.

A metodologia de seleção deve ser adequada para maximizar os ganhos genéticos para obtenção de populações superiores. Neste sentido, o objetivo deste trabalho foi avaliar os ganhos genéticos com a seleção para o caráter rendimento de polpa por fruto em açaizeiro com base na seleção entre e dentro de famílias e massal. A avaliação dos frutos foi realizada durante o período de 2005 a 2007, em um experimento de 25 progênies de meios irmãos de açaizeiro. O rendimento de polpa apresentou correlação positiva para o peso de polpa e negativa para comprimento, largura, peso do fruto e da semente, o que, juntamente com a seleção massal, possibilita a obtenção de uma população com frutos mais uniformes e de maior rendimento de polpa