Coordinate and time-dependent diffusion dynamics in protein folding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Naturally light invisible axion in models with large local discrete symmetries

We show that by introducing appropriate local Z(N)(Ngreater than or equal to13) symmetries in electroweak models it is possible to implement an automatic Peccei-Quinn symmetry, at the same time keeping the axion protected against gravitational effects. Although we consider here only an extension of the standard model and a particular 3-3-1 model, the strategy can be used in any kind of electroweak model. An interesting feature of this 3-3-1 model is that if we add (i) right-handed neutrinos, (ii) the conservation of the total lepton number, and (iii) a Z(2) symmetry, the Z(13) and the chiral Peccei-Quinn U(1)P-Q symmetries are both accidental symmetries in the sense that they are not imposed on the Lagrangian but are just a consequence of the particle content of the model, its gauge invariance, renormalizability, and Lorentz invariance. In addition, this model has no domain wall problem.

Deciphering the minimum of energy of some walking technicolor models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

New class of spin projection operators for 3D models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mini-implant and Nance button for initial retraction of maxillary canines: a prospective study in cast models

OBJETIVO: a ancoragem óssea é fundamental para o sucesso do tratamento de algumas más oclusões, pois permite a aplicação de forças contínuas, diminui o tempo de tratamento e independe da colaboração do paciente. MÉTODOS: o propósito desse trabalho foi comparar, por meio de modelos dentários, a perda de ancoragem após a retração inicial de caninos superiores entre dois grupos. O grupo A utilizou o mini-implante enquanto o grupo B utilizou o Botão de Nance. Para todos os pacientes foram realizados dois modelos (M1 e M2). Os primeiros modelos foram realizados ao início (M1), e os outros ao final da retração inicial de canino (M2). RESULTADOS: todas as medidas foram tabuladas e submetidas à análise estatística. Para verificar o erro sistemático intraexaminador foi utilizado o teste t pareado. Na determinação do erro casual utilizou-se o cálculo de erro proposto por Dahlberg. Para comparação entre as fases Início e Após, foi utilizado o teste t pareado. Para a comparação entre os grupos de mini-implante e Botão de Nance, foi utilizado o teste t de Student para medidas independentes. em todos os testes foi adotado nível de significância de 5% (p<0,05). CONCLUSÃO: ao se medir e comparar em modelos dentários a perda de ancoragem dos molares após a retração inicial de canino utilizando-se dois sistemas de ancoragem distintos (Mini-implante e Botão de Nance), pôde-se observar a inexistência de diferença estatisticamente significativa entre os dois grupos.

Thermal comfort in reduced models of broilers' houses, under different types of roofing materials

Esta pesquisa foi conduzida com o objetivo de avaliar diferentes tipos de coberturas em instalações para aves, por meio do Índice de Temperatura de Globo Negro e Umidade (ITGU), Carga Térmica de Radiação (CTR) e Entalpia (H). O experimento foi conduzido na Universidade Estadual de Goiás, entre os meses de abril e maio de 2011, sendo composto por cinco tratamentos (coberturas): CA -Telha de cimento-amianto; BA -Telha de bambu; BAP -Telha de bambu pintada de branco; FB -Telha de fibra vegetal e betume; FBP -Telha de fibra vegetal e betume pintada de branco, com 15 repetições, sendo as repetições os dias de medição. Dentre os horários estudados, o considerado menos confortável foi às 14h, sendo que a cobertura de fibra vegetal e betume foi a que apresentou maior valor de ITGU (84,1) quando comparada às demais coberturas, caracterizando uma situação de menor conforto térmico, não sendo observada diferença para CTR e H entre os tratamentos na região estudada.

First-order decay models to describe soil C-CO2 Loss after rotary tillage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A SIMPLE NUMERICAL-METHOD FOR HYDROSTATIC INCOMPRESSIBLE MODELS WITH RIGID LIDS

A simple and easily implemented method is developed to keep the vertical velocity equal to zero at the bottom and top of hydrostatic incompressible numerical models. The pressure is computed at the top by correcting its value given in the previous time step so that the vertical integral of the horizontal divergence is zero at each column. Numerical experiments that exhibit small time variations of pressure at the top are able to simplify the algorithm and save computer time. Numerical simulations illustrate the method effectiveness for a horizontal deformation-induced frontogenesis.

Effects of erythrinian alkaloids isolated from Erythrina mulungu (Papilionaceae) in mice submitted to animal models of anxiety

The effects of acute oral administration of erythrinian alkaloids, Le. (+)-alpha-hydroxy-erysotrine, erythravine and (+)-11 alpha-hydroxy-erythravine isolated from the flowers of Erythrina mulungu were investigated in two animal models of anxiety in mice-the light-dark transition model (LDTM) and the elevated plus-maze (EPM). In the LDTM, erythravine (3, 10 mg/kg) and (+)-11 alpha-hydroxy-erythravine (10mg/kg) increased the time spent by the animals in the illuminated compartment and (+)-11 alpha-hydroxy-erythravine (3 mg/kg) increased the number of transitions between compartments of the LDTM, suggesting an anxiolytic-like effect of these erythrinian alkaloids. Nevertheless, the third alkaloid studied, (+)-alpha-hydroxy-erysotrine, did not change any behavioral response with the range of doses used (3-10 mg/kg). Since the oral administration of the crude extract of E. mulungu (EM) (100-400 mg/kg) did not modify the conventional measures of anxiety in the EPM, this animal model was not chosen to evaluate the anxiolytic properties of the isolated alkaloids. These results suggest that the alkaloids erythravine and (+)-11 alpha-hydroxy-erythravine are responsible for the anxiolytic effects of the crude extract of E. mulungu.

THE CONSERVED CHARGES AND INTEGRABILITY OF THE CONFORMAL AFFINE TODA MODELS

We construct infinite sets of local conserved charges for the conformal affine Toda model. The technique involves the abelianization of the two-dimensional gauge potentials satisfying the zero-curvature form of the equations of motion. We find two infinite sets of chiral charges and apart from two lowest spin charges, all the remaining ones do not possess chiral densities. Charges of different chiralities Poisson commute among themselves. We discuss the algebraic properties of these charges and use the fundamental Poisson bracket relation to show that the charges conserved in time are in involution. Connections to other Toda models are established by taking particular limits.

Fluoride dose response in pH-cycling models using bovine enamel

The aim of this study was to establish methodologies for verification of the fluoride solution dose-response relationship using bovine enamel and pH-cycling models. Six models of the cariogenic challenge were performed, varying the time of demineralization and pH, time of remineralization, composition of de- and remineralization solutions, frequency and time of application of treatment solutions and pH-cycling duration. For the evaluation of the fluoride effect on caries dynamics, two proposed models provided for improvement in standardization of methods leading to a higher level of precision, demonstrating a dose response between treatments with regard to surface microhardness and Delta Z. For the evaluation of the fluoride effect on enamel remineralization, the addition of fluoride to the de- and remineralization solutions and the reduction of frequency and time of application of fluoride solutions led to a more suitable pH-cycling model. Copyright (C) 2005 S. Karger AG, Basel.

Analysis of the Stayability in Milk Buffaloes using Survival Models

In this study the trait Stayability (SA) was evaluated according to the year of cull after first calvin, i.e., SA 1 to 6 for 1 to 6 years from first calving in lactating females from bubaline milk herds spread in nine farms located in São Paulo state. Informations were used regarding 1027 lactating Murrah breed buffaloes. The statistical analyses were made using LIFEREG (SAS, 1999) procedure. The SA was evaluated using the fixed effects: farm production, birth year, calving season (Season 1- April to September and Season 2 October - March) and class of milk yield at 270 days. The age at first calving (AFC) was considered as a random effect. The mean observed for total milk yield was 1458.75Kg. Calving Season 2 encloses 65.6% of births. The means of cull age, in months, and the percentage of SA were, respectively: 10.69 e 69% (SA1), 19.30 e 63% (SA2), 26.4 e 54% (SA3), 33.15 e 42% (SA4), 38.53 e 36% (SA5) e 42.65 e 26% (SA6). It is verified that most of culls happens after the first lactation, among the sixth and eleventh month after first calving. It was observed that the factors: farm production, birth year and class of milk yield at 270 days affected significantly all SAs. Factors like calving season and the age at first calving (AFC) were only significant for SAL Being significant the factor AFC in level of 1% and factor time in 10%. For other SAs these factors were not statistically significant.

Predicting beef carcass retail products of Mediterranean buffaloes by real-time ultrasound measures

Twenty eight Mediterranean buffaloes bulls were scanned with real-time ultrasound (RTU), slaughtered, and fabricated into retail cuts to determine the potential for ultrasound measures to predict carcass retail yield. Ultrasound measures of fat thickness, ribeye area and rump fat thickness were recorded three to five days prior to slaughter. Carcass measurements were taken, and one side of each carcass was fabricated into retail cuts. Stepwise regression analysis was used to compare possible models for prediction of either kilograms or percent retail product from carcass mesaurements and ultrasound measures. Results indicate that possible prediction models for percent or kilograms of retail products using RTU measures were similar in their predictive power and accuracy when compared to models derived from carcass measurements. Both fat thickness and ribeye area were over-predicted when measured ultrasonically compared to measurements taken on the carcass in the cooler. The mean absolute differences for both traits are larger than the mean differences, indicating that some images were interpreted to be larger and some smaller than actual carcass measurements. Ultrasound measurements of REA and FT had positive correlations with carcass measures of the same traits (r=.96 for REA and r=.99 for FT). Standard errors of prediction currently are being used as the standard to certify ultrasound technicians for accuracy. Regression equations using live weight (LW), rib eye area (REAU) and subcutaneous fat thickness (FTU) between 12(th) and 13 (th) ribs and also over the biceps femoris muscle (FTP8) by ultrasound explained 95% of the variation in the hot carcass weight when measure immediately before slaughter.

Bayesian longitudinal data analysis with mixed models and thick-tailed distributions using MCMC

Linear mixed effects models are frequently used to analyse longitudinal data, due to their flexibility in modelling the covariance structure between and within observations. Further, it is easy to deal with unbalanced data, either with respect to the number of observations per subject or per time period, and with varying time intervals between observations. In most applications of mixed models to biological sciences, a normal distribution is assumed both for the random effects and for the residuals. This, however, makes inferences vulnerable to the presence of outliers. Here, linear mixed models employing thick-tailed distributions for robust inferences in longitudinal data analysis are described. Specific distributions discussed include the Student-t, the slash and the contaminated normal. A Bayesian framework is adopted, and the Gibbs sampler and the Metropolis-Hastings algorithms are used to carry out the posterior analyses. An example with data on orthodontic distance growth in children is discussed to illustrate the methodology. Analyses based on either the Student-t distribution or on the usual Gaussian assumption are contrasted. The thick-tailed distributions provide an appealing robust alternative to the Gaussian process for modelling distributions of the random effects and of residuals in linear mixed models, and the MCMC implementation allows the computations to be performed in a flexible manner.

Incorporating voltage/reactive representation to short-term generation scheduling models

This paper proposes a methodology to incorporate voltage/reactive representation to Short Term Generation Scheduling (STGS) models, which is based on active/reactive decoupling characteristics of power systems. In such approach STGS is decoupled in both Active (AGS) and Reactive (RGS) Generation Scheduling models. AGS model establishes an initial active generation scheduling through a traditional dispatch model. The scheduling proposed by AGS model is evaluated from the voltage/reactive points of view, through the proposed RGS model. RGS is formulated as a sequence of T nonlinear OPF problems, solved separately but taking into account load tracking between consecutive time intervals. This approach considerably reduces computational effort to perform the reactive analysis of the RGS problem as a whole. When necessary, RGS model is capable to propose active generation redispatches, such that critical reactive problems (in which all reactive variables have been insufficient to control the reactive problems) can be overcome. The formulation and solution methodology proposed are evaluated in the IEEE30 system in two case studies. These studies show that the methodology is robust enough to incorporate reactive aspects to STGS problem.