Experimental Determination of Thermal Entanglement in Spin Clusters using Magnetic Susceptibility Measurements

The present work reports an experimental observation of thermal entanglement in a clusterized spin chain formed in the compound Na$_2$Cu$_5$Si$_4$O$_{14}$. The presence of entanglement was investigated through two measured quantities, an Entanglement Witness and the Entanglement of Formation, both derived from the magnetic susceptibility. It was found that pairwise entanglement exists below $\sim 200$ K. Tripartite entanglement was also observed below $\sim 240$ K. A theoretical study of entanglement evolution as a function of applied field and temperature is also presented.Comment: Submited to Phys. Rev.

Evidence for entanglement at high temperatures in an engineered molecular magnet

The molecular compound [Fe$_{2}$($\mu_{2}$-oxo)(C$_{3}$H$_{4}$N$_{2}$)$_{6}$(C$_{2}$O$_{4}$)$_{2}$] was designed and synthesized for the first time and its structure was determined using single-crystal X-ray diffraction. The magnetic susceptibility of this compound was measured from 2 to 300 K. The analysis of the susceptibility data using protocols developed for other spin singlet ground-state systems indicates that the quantum entanglement would remain at temperatures up to 732 K, significantly above the highest entanglement temperature reported to date. The large gap between the ground state and the first-excited state (282 K) suggests that the spin system may be somewhat immune to decohering mechanisms. Our measurements strongly suggest that molecular magnets are promising candidate platforms for quantum information processing

Herança da resistência de variedades comerciais brasileiras de soja à podridão radicular de fitóftora.

O objetivo do estudo foi avaliar a herança da resistência à podridão radicular de fitóftora, causada por causada por Phytophthora sojae (Kaufm. & Gerd.), presentes em variedades comerciais resistentes BRS 260, BRS 262, BRS 246RR e BRSMG 752S. Até hoje 14 genes, denominados Rps, foram descritos por conferirem resistência à PRF, os quais tem sido amplamente utilizados nos programas de melhoramento para proteção das cultivares de soja. O material experimental foi desenvolvido a partir do cruzamento das quatro cultivares entre si, totalizando seis cruzamentos. A população F2, os parentais utilizados nos cruzamentos e a cultivar suscetível BRS 268, foram inoculados com o patógeno utilizando a metodologia de Keeling (1982), adaptada por Yorinori (1996). O teste do qui-quadrado (?2) foi aplicado para aceitar ou rejeitar os padrões de segregação encontrados de plantas mortas e não-mortas esperadas para a população F2 segundo padrões mendelianos. O cruzamento BRS 260 x BRS 246RR não resultou em nenhum indivíduo morto, com isso conclui-se que os mesmos contém um gene de resistência no mesmo loco conferindo resistência a P. sojae. Nos cruzamentos BRSMG 752S x BRS 260 e BRS 246RR x BRSMG 752S foram observados padrões de segregação semelhantes, correspondentes à segregação de dois genes dominantes independentes. As três combinações de cruzamentos envolvendo a cultivar BRS 262 indicam a presença de três genes segregando independentemente nesses cruzamentos. Pode-se concluir que apenas nesse grupo de quatro cultivares resistentes já existem quatro locos de resistência à P. sojae disponíveis para serem explorados em programas de melhoramento de soja

Empiricism and stochastics in cellular automaton modeling of urban land use dynamics

An increasing number of models for predicting land use change in regions of rapidurbanization are being proposed and built using ideas from cellular automata (CA)theory. Calibrating such models to real situations is highly problematic and to date,serious attention has not been focused on the estimation problem. In this paper, wepropose a structure for simulating urban change based on estimating land usetransitions using elementary probabilistic methods which draw their inspiration fromBayes' theory and the related ?weights of evidence? approach. These land use changeprobabilities drive a CA model ? DINAMICA ? conceived at the Center for RemoteSensing of the Federal University of Minas Gerais (CSR-UFMG). This is based on aneight cell Moore neighborhood approach implemented through empirical land useallocation algorithms. The model framework has been applied to a medium-size townin the west of São Paulo State, Bauru. We show how various socio-economic andinfrastructural factors can be combined using the weights of evidence approach whichenables us to predict the probability of changes between land use types in differentcells of the system. Different predictions for the town during the period 1979-1988were generated, and statistical validation was then conducted using a multipleresolution fitting procedure. These modeling experiments support the essential logicof adopting Bayesian empirical methods which synthesize various information aboutspatial infrastructure as the driver of urban land use change. This indicates therelevance of the approach for generating forecasts of growth for Brazilian citiesparticularly and for world-wide cities in general

Monitoramento do comportamento do rio Paraguai no Pantanal Sul-Mato-grossense-2008/2009.

Este trabalho visa dar continuidade ao programa de monitoramento do comportamento do rio Paraguai que é feito anualmente pela Embrapa Pantanal.bitstream/CPAP-2010/57313/1/COT80.pd

Group Theory analysis of phonons in two-dimensional Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDCs) have emerged as a new two dimensional materials field since the monolayer and few-layer limits show different properties when compared to each other and to their respective bulk materials. For example, in some cases when the bulk material is exfoliated down to a monolayer, an indirect-to-direct band gap in the visible range is observed. The number of layers $N$ ($N$ even or odd) drives changes in space group symmetry that are reflected in the optical properties. The understanding of the space group symmetry as a function of the number of layers is therefore important for the correct interpretation of the experimental data. Here we present a thorough group theory study of the symmetry aspects relevant to optical and spectroscopic analysis, for the most common polytypes of TMDCs, i.e. $2Ha$, $2Hc$ and $1T$, as a function of the number of layers. Real space symmetries, the group of the wave vectors, the relevance of inversion symmetry, irreducible representations of the vibrational modes, optical selection rules and Raman tensors are discussed.Comment: 32 pages, 4 figure

Erlang Code Evolution Control

During the software lifecycle, a program can evolve several times for different reasons such as the optimisation of a bottle-neck, the refactoring of an obscure function, etc. These code changes often involve several functions or modules, so it can be difficult to know whether the correct behaviour of the previous releases has been preserved in the new release. Most developers rely on a previously defined test suite to check this behaviour preservation. We propose here an alternative approach to automatically obtain a test suite that specifically focusses on comparing the old and new versions of the code. Our test case generation is directed by a sophisticated combination of several already existing tools such as TypEr, CutEr, and PropEr; and other ideas such as allowing the programmer to chose an expression of interest that must preserve the behaviour, or the recording of the sequences of values to which this expression is evaluated. All the presented work has been implemented in an open-source tool that is publicly available on GitHub.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

Integração de métodos de modelação geométrica, elementos finitos e programação matemática no projecto estructural

A optimizacáo de forma de componentes estruturais, sujeitos a esforcos de membrana, é obtida recorrendo a um modelo numérico que integra modelacáo geométrica, análise por elementos finitos e programacáo matemática. Curvas paramétricas SEO utilizadas para definir a fronteira do domínio, sendo a posicáo dos seus nós assumida como variáveis de projecto. Para cada configuraciio, um gerador de malhaelíptico permite obter automáticamente a discretizacáo elíptico necessári a A solucáo por elementos finitos. As sensibilidades sáo calculadas pela técnica semi-analítica e pelo método directo, podendo ser visualizadas gráficamente.. O método da programacáo sequencial convexa é utilizado na fase de optimizacao. A implementacao é feita com enfase na utilizacáo de gráficos interactivos e em linguagens de programacáo normalizadas, de forma a permitir a portabilidade do sistema desenvolvido.Shape optimization of two dimensional elasticity problems is obtained with a numerical model which integrates geometric modelling, finite elements analysis and mathematical programming. Parametric curves are used to define the boundary of the domain, the position of their nodes is taken as design variables. For each configuration, an elliptic mesh generator obtains automatically the finite element discretization necessary to get the solution. Sensibilities are calculated by the semi-analiticat technique and by the direct method, and can be visualized graphicaly. The method of sequencial con'vex programming is used at the optimization phase. Implementation is made with emphasys on interactive graphics and in standard computer languages, allowing portability of the developed system.Peer Reviewe