Continuity of the Maximum-Entropy Inference

We study the inverse problem of inferring the state of a finite-level quantum system from expected values of a fixed set of observables, by maximizing a continuous ranking function. We have proved earlier that the maximum-entropy inference can be a discontinuous map from the convex set of expected values to the convex set of states because the image contains states of reduced support, while this map restricts to a smooth parametrization of a Gibbsian family of fully supported states. Here we prove for arbitrary ranking functions that the inference is continuous up to boundary points. This follows from a continuity condition in terms of the openness of the restricted linear map from states to their expected values. The openness condition shows also that ranking functions with a discontinuous inference are typical. Moreover it shows that the inference is continuous in the restriction to any polytope which implies that a discontinuity belongs to the quantum domain of non-commutative observables and that a geodesic closure of a Gibbsian family equals the set of maximum-entropy states. We discuss eight descriptions of the set of maximum-entropy states with proofs of accuracy and an analysis of deviations.Comment: 34 pages, 1 figur

Nucleation of a sodium droplet on C60

We investigate theoretically the progressive coating of C60 by several sodium atoms. Density functional calculations using a nonlocal functional are performed for NaC60 and Na2C60 in various configurations. These data are used to construct an empirical atomistic model in order to treat larger sizes in a statistical and dynamical context. Fluctuating charges are incorporated to account for charge transfer between sodium and carbon atoms. By performing systematic global optimization in the size range 1<=n<=30, we find that Na_nC60 is homogeneously coated at small sizes, and that a growing droplet is formed above n=>8. The separate effects of single ionization and thermalization are also considered, as well as the changes due to a strong external electric field. The present results are discussed in the light of various experimental data.Comment: 17 pages, 10 figure

Detecção molecular e análise filogenética de vírus respiratório sincicial bovino (BRSV) em swabs e tecido pulmonar de bovinos adultos

O vírus respiratório sincicial bovino (BRSV) é um dos agentes etiológicos de pneumonias em bovinos jovens. Poucos estudos foram realizados visando à detecção do agente em amostras coletadas de animais adultos, e em especial de bovinos assintomáticos. No entanto, presume-se que as infecções ocorridas nestes grupos possam ocorrer em sua maioria de forma assintomática e este seria um mecanismo importante para manutenção do BRSV nos rebanhos. No presente estudo, o objetivo foi realizar uma análise da prevalência de infecções assintomáticas pelo BRSV em pulmões (n=68) e swabs nasais (209) coletados de bovinos adultos coletadas em frigoríficos da região Sul e Sudeste respectivamente, no sentido de detectar por intermédio de reação da polimerase em cadeia qual a taxa de animais infectados em populações de animais adultos onde não ocorram sinais clínicos da infecção. As amostras positivas à RT-PCR (6) foram posteriormente submetidas ao corte com enzimas de restrição (REA) e sequenciamento para caracterização genética do gene F (2 das amostras). Todas as amostras se enquadram no subgrupo B de BRSV, o grupo circulante no Brasil conforme estudos anteriores. Os resultados obtidos demonstram que o BRSV pode estar presente em amostras obtidas de animais sadios, reforçando a hipótese de que infecções subclínicas fazem parte do mecanismo de manutenção do vírus nos rebanhos

Vascular Remodeling in Health and Disease

The term vascular remodeling is commonly used to define the structural changes in blood vessel geometry that occur in response to long-term physiologic alterations in blood flow or in response to vessel wall injury brought about by trauma or underlying cardiovascular diseases.1, 2, 3, 4 The process of remodeling, which begins as an adaptive response to long-term hemodynamic alterations such as elevated shear stress or increased intravascular pressure, may eventually become maladaptive, leading to impaired vascular function. The vascular endothelium, owing to its location lining the lumen of blood vessels, plays a pivotal role in regulation of all aspects of vascular function and homeostasis.5 Thus, not surprisingly, endothelial dysfunction has been recognized as the harbinger of all major cardiovascular diseases such as hypertension, atherosclerosis, and diabetes.6, 7, 8 The endothelium elaborates a variety of substances that influence vascular tone and protect the vessel wall against inflammatory cell adhesion, thrombus formation, and vascular cell proliferation.8, 9, 10 Among the primary biologic mediators emanating from the endothelium is nitric oxide (NO) and the arachidonic acid metabolite prostacyclin [prostaglandin I2 (PGI2)], which exert powerful vasodilatory, antiadhesive, and antiproliferative effects in the vessel wall

Hábitos e práticas alimentares em três localidades da cidade de São Paulo (Brasil) Eating habits and practices in three localities within the city of São Paulo (Brazil)

Este trabalho teve como objetivo principal o estudo do consumo alimentar em três localidades na cidade de São Paulo. Um inquérito alimentar foi realizado, nos meses de julho e agosto de 1993, junto a trinta e duas mulheres, apresentando características socioeconômicas distintas: 11 na Favela de São Remo (baixa renda), 11 na Vila Madalena (renda média) e 10 no Parque Continental (renda alta). Utilizou-se o método recordatório de 24 horas e o de freqüência alimentar, além de questões abertas sobre hábitos, práticas e estratégias alimentares. Observou-se semelhanças entre os grupos estudados, como por exemplo, o aumento do consumo de alimentos industrializados, o supermercado como principal local de compra de alimentos, a importância dada à carne, às frutas e aos legumes, a preferência por alimentos frescos em relação aos industrializados, as substituições ligadas à evolução dos preços dos alimentos e/ou preocupações com a saúde. Por outro lado, prevaleceu a diferenciação do consumo em função das condições socioeconômicas das famílias, verificada pela maior diversificação alimentar com a elevação da renda, com diferenças significativas (p<0,05) entre o grupo de menor renda e os demais, principalmente, quanto ao consumo de derivados do leite e de legumes em conserva.<br>The principal objective of this study was an assessment of food consumption in three localities within the city of São Paulo. A food inquiry was undertaken in the months of July and August, 1993, involving thirty-two women who presented distinct socio-economic characteristics: eleven from São Remo shanty-town (low income), eleven from Vila Madalena (medium income) and ten from Parque Continental (high income).The 24-hour recall and the eating frequency methods were used, as well as open questions about eating habits, practices and strategies. Similarities were observed among the groups studied: for example, the increase in the consumption of industrialized food-stuffs, the supermarket as the principal shopping place, the importance given to meat, fruits and vegetables in the diet, the preference for fresh foods rather than industrialized ones, and changes related to the shifts in the prices of food-stuffs and/or to the preoccupation with health. On the other hand, the differentiation of consumption due to the socioeconomic status of the families prevailed, evidenced by the greater diversification in food-stuffs consumed in accordance with the position on the income scale, with significant differences (p<0,05) between the lowest income group and the others, mainly regarding the consumption of dairy products and vegetable conserves