Dimensional-scaling estimate of the energy of a large system from that of its building blocks: Hubbard model and Fermi liquid

A simple, physically motivated, scaling hypothesis, which becomes exact in important limits, yields estimates for the ground-state energy of large, composed, systems in terms of the ground-state energy of its building blocks. The concept is illustrated for the electron liquid, and the Hubbard model. By means of this scaling argument the energy of the one-dimensional half-filled Hubbard model is estimated from that of a 2-site Hubbard dimer, obtaining quantitative agreement with the exact one-dimensional Bethe-Ansatz solution, and the energies of the two- and three-dimensional half-filled Hubbard models are estimated from the one-dimensional energy, recovering exact results for $U\to 0$ and $U\to \infty$ and coming close to Quantum Monte Carlo data for intermediate $U$.Comment: 3 figure

The effect of translational and rotational relative velocity components on fluid-to-particle heat transfer coefficients in continuous tube flow

A liquid crystal technique was used to determine average fluid-to-particle heat transfer coefficients (hfp) for single spherical hollow aluminium particles heating in carboxymethylcellulose solutions in continuous tube flow. The particles' linear and rotational velocities were also measured by videotaping the particle motion at a bottom position. Particles with different diameter and density were used in solutions with different viscosities and at different flow rates (7 < Reynolds < 284; 144 < Prandtl < 1755). The values of the average heat transfer coefficient were between 334 and 1497 W/m2C. The results showed that both the relative fluid-to-particle velocity and the particle rotational velocity influence the heat transfer coefficients, although it is not possible to individualize their effects. However, the addition of the individual effects, predicted by using published dimensionless correlations, yielded a good fit with the experimental values

Genetic evaluation of partial growth trajectory of Santa Inês breed using random regression models.

ABSTRACT - It was evaluated data set of 19,303 weight records of Santa Inês sheep in order to evaluate distinct polynomial functions with different order for better adjustements of fixed and random regressions of growth trajectory and to estimate (co)variances components and genetic parameters of this trajectory. Fixed effects used in analysis were contemporary group, sex and birth type. Ordinary and Legendre polynomials, ranging from two to four orders, were evaluated for fixed regression of average growth trajectory. Legendre and quadratic b-spline functions, ranging from three to four orders, were evaluated for random regressions. Legendre polynomials of order fourth were suitable to fit random regression, while ordinary polynomials of third order were the best for fixed trajectory. Direct heritabilities on days 1, 50, 150, 250 and 411 were 0.24, 0.12, 0.44, 0.84, and 0.96, respectively, while maternal heritabilities for the same ages were 0.24, 0.19, 0.09, 0.02, and 0.01, respectively. Genetic correlations among weights in subsequent ages were high, tending to unity, and there were negative correlations between weights at early ages and weights at late ages. It is possible to modify the growth trajectory by selection with the observed genetic variability. Genetic control of weights at initial ages is not the same in late ages. So, selection of animals for slaughter in early age must be different from that of replacement animals. Avaliação genética de parte da trajetória de crescimento em ovinos da raça Santa Inês utilizando modelos de regressão aleatória. Resumo - Foram utilizados 19.303 registros de peso de ovinos da raça Santa Inês com os objetivos de avaliar funções polinomiais com diferentes ordens para melhor ajuste das regressões fixas e aleatórias da trajetória de crescimento e estimar os componentes de covariância e os parâmetros genéticos desta trajetória. Os efeitos fixos utilizados nas análises foram grupo de contemporâneos, sexo e tipo de nascimento. Para ajuste da regressão fixa da trajetória média de crescimento, foram avaliados polinômios ordinários e de Legendre com ordens variando de 2 a 4. Para as regressões aleatórias, foram avaliadas as funções de Legendre e ?-spline quadrática, com ordens variando de 3 a 4. As funções com polinômios de Legendre de quarta ordem foram adequadas para ajustar a parte aleatória, enquanto os polinômios ordinários de terceira ordem foram melhores para ajustar a parte fixa. As herdabilidades diretas nos dias 1, 50, 150, 250 e 411 foram de 0,24; 0,12; 0,44; 0,84; e 0,96, respectivamente, enquanto as herdabilidades maternas nessas idades foram de 0,24; 0,19; 0,09; 0,02 e 0,01. As correlações genéticas entre pesos em idades subsequentes foram elevadas, tendendo à unidade, e houve correlações negativas entre pesos tomados em idades mais jovens e aqueles tomados em idades mais avançadas. A variabilidade genética observada permite alterar a trajetória de crescimento por meio de seleção. O controle genético dos pesos nas fases iniciais do crescimento não é o mesmo que atua em idades mais tardias. Assim, a seleção de animais para abate em idade jovem deve ser diferente daquela para animais de reposição no rebanho

Incidência da mastite subclínica em rebanhos leiteiros de agricultores familiares do município de Cruz das Almas, Bahia.

ZOOTEC 2009

Diagnosis and outcome of oesophageal Crohn's disease

BACKGROUND AND AIMS: Crohn's disease (CD) can involve any part of the gastrointestinal tract. We aimed to characterize clinical, endoscopic, histologic features and treatment outcomes of CD patients with oesophageal involvement. METHODS: We collected cases through a retrospective multicentre European Crohn's and Colitis Organisation CONFER [COllaborative Network For Exceptionally Rare case reports] project. Clinical data were recorded in a standardized case report form. RESULTS: A total of 40 patients were reported [22 males, mean (±SD, range) age at oesophageal CD diagnosis: 25 (±13.3, 10-71) years and mean time of follow-up: 67 (±68.1, 3-240) months]. Oesophageal involvement was established at CD diagnosis in 26 patients (65%) and during follow-up in 14. CD was exclusively located in the oesophagus in 2 patients. Thirteen patients (32.2%) were asymptomatic at oesophageal disease diagnosis. Oesophageal strictures were present in 5 patients and fistulizing oesophageal disease in one. Eight patients exhibited granulomas on biopsies. Proton-pump inhibitors (PPIs) were administered in 37 patients (92.5%). Three patients underwent endoscopic dilation for symptomatic strictures and none oesophageal-related surgery. Diagnosis in pre-established CD resulted in treatment modifications in 9/14 patients. Clinical remission of oesophageal disease was seen in 33/40 patients (82.5%) after a mean time of 7 (±5.6, 1-18) months. Follow-up endoscopy was performed in 29/40 patients and 26/29 (89.7%) achieved mucosal healing. CONCLUSION: In this case series the endoscopic and histologic characteristics of isolated oesophageal CD were similar to those reported in other sites of involvement. Treatment was primarily conservative, with PPIs administered in the majority of patients and modifications in pre-existing IBD-related therapy occurring in two thirds of them. Clinical and endoscopic remission was achieved in more than 80% of the patients.info:eu-repo/semantics/publishedVersio

Substituição da torta de algodão por feno de leguminosas em rações baseadas em restolho da cultura do milho para ovinos em confinamento.

Resumo: Dois experimentos usando ovinos deslanados testaram a substituiçao da torta de algodao por feno de Ieguminosas em rações corn restolho da cultura do milho. No primeiro experimento, foi usada uma raçao-base de 51% restolho do milho, 28% torta de algodao, 20% milho e 1% sal, na quaI a torta de algodao foi substituîda por 5%, 10%, e 15% de feno de mata-pasto (Cassia sericea), enquanto um Iote-testemunha era mantido em pastoreio. Os animais confinados ganharam 95, 106, 103 e 93 gramas/cabeça/dia (P > 0,05), para as rações com 0%, 5%, 10% e 15% de mata-pasto, respectivamente. Os animais em pastoreio perderam 11 gramas/cabeça/dia (P 0.05) for tho rations with 0%, 5%, 10% and 15% of "mata-pasto", respective-ly. The grazing animais iost 11 grams/head/day , (P <0.05). in the second experiment, the cottonseed calce was either partiaiiy (50%) or totaily repiacod by "mata-pasto" or "cunha" (ditaria terl7atee) hays, whiie the grazing sheep received a suppiementation of 200 grams of corn grain/headldayWith the exception of the treatment In which the eottonseed cake was totaily repiaced by "mata-pasto" hay, the other treatments with coniined animais showed gains above 100 grams/head/day, which were hi -,er than (P <0.01) the 42 grams/head/day for the grazing animais. The resuits indicate that it is possibie to substituto "mata-pasto" hay for cottonseed calce ar leveis up to 50%, while the total substitution Lan be made "cunhâ" Is used

Correlations between structure and dynamics in complex networks

Previous efforts in complex networks research focused mainly on the topological features of such networks, but now also encompass the dynamics. In this Letter we discuss the relationship between structure and dynamics, with an emphasis on identifying whether a topological hub, i.e. a node with high degree or strength, is also a dynamical hub, i.e. a node with high activity. We employ random walk dynamics and establish the necessary conditions for a network to be topologically and dynamically fully correlated, with topological hubs that are also highly active. Zipf's law is then shown to be a reflection of the match between structure and dynamics in a fully correlated network, as well as a consequence of the rich-get-richer evolution inherent in scale-free networks. We also examine a number of real networks for correlations between topology and dynamics and find that many of them are not fully correlated.Comment: 16 pages, 7 figures, 1 tabl