Desenvolvimento e caracterização de filmes de TiO2 para aplicação como fotocatalisadores em processos oxidativos avançados.

bitstream/item/77115/1/CT112-2010.pd

Simulations of a mortality plateau in the sexual Penna model for biological ageing

The Penna model is a strategy to simulate the genetic dynamics of age-structured populations, in which the individuals genomes are represented by bit-strings. It provides a simple metaphor for the evolutionary process in terms of the mutation accumulation theory. In its original version, an individual dies due to inherited diseases when its current number of accumulated mutations, n, reaches a threshold value, T. Since the number of accumulated diseases increases with age, the probability to die is zero for very young ages (n = T). Here, instead of using a step function to determine the genetic death age, we test several other functions that may or may not slightly increase the death probability at young ages (n < T), but that decreases this probability at old ones. Our purpose is to study the oldest old effect, that is, a plateau in the mortality curves at advanced ages. Imposing certain conditions, it has been possible to obtain a clear plateau using the Penna model. However, a more realistic one appears when a modified version, that keeps the population size fixed without fluctuations, is used. We also find a relation between the birth rate, the age-structure of the population and the death probability.Comment: submitted to Phys. Rev.

Hand and ultrasonic instrumentation for orthograde root canal treatment of permanent teeth.

UNLABELLED: Root canal treatment is a frequently performed dental procedure and is carried out on teeth in which irreversible pulpitis has led to necrosis of the dental pulp. Removal of the necrotic tissue remnants and cleaning and shaping of the root canal are important phases of root canal treatment. Treatment options include the use of hand and rotary instruments and methods using ultrasonic or sonic equipment. OBJECTIVES: The objectives of this systematic review of randomized controlled trials were to determine the relative clinical effectiveness of hand instrumentation versus ultrasonic instrumentation alone or in conjunction with hand instrumentation for orthograde root canal treatment of permanent teeth. MATERIAL AND METHODS: The search strategy retrieved 226 references from the Cochrane Oral Health Group Trials Register (7), the Cochrane Central Register of Controlled Trials (CENTRAL) (12), MEDLINE (192), EMBASE (8) and LILACS (7). No language restriction was applied. The last electronic search was conducted on December 13th, 2007. Screening of eligible studies was conducted in duplicate and independently. RESULTS: Results were to be expressed as fixed-effect or random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. Heterogeneity was to be investigated including both clinical and methodological factors. No eligible randomized controlled trials were identified. CONCLUSIONS: This review illustrates the current lack of published or ongoing randomized controlled trials and the unavailability of high-level evidence based on clinically relevant outcomes referring to the effectiveness of ultrasonic instrumentation used alone or as an adjunct to hand instrumentation for orthograde root canal treatment. In the absence of reliable research-based evidence, clinicians should base their decisions on clinical experience, individual circumstances and in conjunction with patients' preferences where appropriate. Future randomized controlled trials might focus more closely on evaluating the effectiveness of combinations of these interventions with an emphasis on not only clinically relevant, but also patient-centered outcomes

The treatment of the infrared region in perturbative QCD

We discuss the contribution coming from the infrared region to NLO matrix elements and/or coefficient functions of hard QCD processes. Strictly speaking, this contribution is not known theoretically, since it is beyond perturbative QCD. For DGLAP evolution all the infrared contributions are collected in the phenomenological input parton distribution functions (PDFs), at some relatively low scale Q_0; functions which are obtained from a fit to the `global' data. However dimensional regularization sometimes produces a non-zero result coming from the infrared region. Instead of this conventional regularization treatment, we argue that the proper procedure is to first subtract from the NLO matrix element the contribution already generated at the same order in \alpha_s by the LO DGLAP splitting function convoluted with the LO matrix element. This prescription eliminates the logarithmic infrared divergence, giving a well-defined result which is consistent with the original idea that everything below Q_0 is collected in the PDF input. We quantify the difference between the proposed treatment and the conventional approach using low-mass Drell-Yan production and deep inelastic electron-proton scattering as examples; and discuss the potential impact on the `global' PDF analyses. We present arguments to show that the difference cannot be regarded as simply the use of an alternative factorization scheme.Comment: 15 pages, 5 figures, title changed, text considerably modified to improve presentation, and discussion section enlarge

Nonlinear finite element analysis of strengthened masonry buildings subject to seismic action

Masonry structures are always used from the past until modern times but due to material degradation, imposed displacements, and structural alterations some members need strengthening to re-establish their performances. In this frame, fiber-reinforced polymer (FRP) composites in the form of bonded laminates applied to the external surface are an effective solution [1,2]. Despite research efforts in the last years, for the seismic analysis of the strengthened masonry system, there is still lack of numerical models, which have the advantages of accurate, high-efficiency and good-convergence [3,4]. In the first part of this paper, numerical approaches to model FRP strengthened masonry structures are discussed and in particular a material model suitable for micro-modelling of the interfacial behaviour FRP-masonry implemented in the Diana finite element (FE) program using a user subroutine is presented [5,6,7]. This micro-modelling approach based on interface elements is then used to develop and validate the global behaviour of a different type of FE that was implemented in the Opensees finite element framework. This new element is extremely effective for the seismic analysis of masonry buildings because of the significant advantage of drastically reducing the number of DOF of the FEM model [8,9,10]. Numerical results are validated by comparison with experimental results from tests performed at the University of Pavia and the Georgia Institute of technology. In particular, it shows a satisfactory degree of accuracy to analyse complex assemblages of masonry buildings including cyclic loads effects and FRP strengthening influence.- (undefined

Toxicidade subcrônica de dois fungicidas e sua mistura na atividade de algumas enzimas de pacu.

Resumo: Estudou-se o efeito sobre a atividade de enzimas hepáticas do metabolismo intermediário, de conjugação e antioxidantes, decorrente da exposição do peixe pacu (Piaractus mesopotamicus) por 14 dias aos fungicidas epoxiconazol, piraclostrobina e à mistura dos mesmos. As atividades da fosfatase ácida (Pac) e superóxido dismutase (SOD) foram aumentadas significativamente (p<0,05) em relação ao controle nas exposições ao epoxiconazol na concentração de 22,8 g.L-1. Esta é equivalente a 1/100 da concentração letal media (CL50-96h) determinada em peixes. Com relação aos efeitos da piraclostrobina e à mistura epoxiconazol+piraclostrobina, não se observou decréscimo ou incremento das atividades das enzimas avaliadas. Atribuíram-se valores de 1,8 e 2,0 micrograma.L-1, respectivamente para piraclostrobina e a mistura epoxiconazol+piraclostrobina, como concentrações de efeito não observado (CENO). O valor deste parâmetro para o epoxiconazol seria equivalente a 2,28 micrograma.L-1, já que observou-se efeito na concentração imediatamente superior a esta. Os dados são relevantes na identificação de possíveis biomarcadores e no direcionamento de políticas publicas quanto ao estabelecimento de níveis máximos de poluentes na água para a proteção da biota aquática. Abstract: We studied the effect on the activity of hepatic enzymes that acts in the intermediary metabolism, conjugation of xenobiotics and as antioxidants, due to the exposure (14 days) of the pacu fish (Piaractus mesopotamicus) to the fungicides epoxiconazole, pyraclostrobin and its mixture. In the epoxiconazole exposure at 22.8 microgramg L-1, the activities of acid phosphatase (Pac) and superoxide dismutase (SOD) were increased significantly (p<0.05) compared to the control. This concentration is equivalent to 1/100 the median lethal concentration (LC50-96h) determined in fishes. There was no significant decrease or increase in the enzyme activities in fishes exposed to pyraclostrobin or pyraclostrobin+epoxiconazole mixture. We assigned values equivalent to 1.8 and 2.0 microgram L-1, respectively for pyraclostrobin and pyraclostrobin+epoxiconazole mixture, which would be regarded as the no observed effect concentration (NOEC). The value of this parameter to the epoxiconazole would be equivalent to 2.28 microgram L-1. Data are relevant in the identification of candidate biomarkers and in guiding public policies regarding the setting of maximum levels of pollutants in the water for protection of the aquatic biota

Desenvolvimento e avaliação de marcadores SNPs de genes relacionados a proteínas de reserva de arroz.

O objetivo deste trabalho foi o de identificar associação entre polimorfismos do tipo SNP com o teor de proteína total em acessos de arroz

The Efficiency of Gravitational Bremsstrahlung Production in the Collision of Two Schwarzschild Black Holes

We examine the efficiency of gravitational bremsstrahlung production in the process of head-on collision of two boosted Schwarzschild black holes. We constructed initial data for the characteristic initial value problem in Robinson-Trautman spacetimes, that represent two instantaneously stationary Schwarzschild black holes in motion towards each other with the same velocity. The Robinson-Trautman equation was integrated for these initial data using a numerical code based on the Galerkin method. The final resulting configuration is a boosted black hole with Bondi mass greater than the sum of the individual mass of each initial black hole. Two relevant aspects of the process are presented. The first relates the efficiency $\Delta$ of the energy extraction by gravitational wave emission to the mass of the final black hole. This relation is fitted by a distribution function of non-extensive thermostatistics with entropic parameter $q \simeq 1/2$; the result extends and validates analysis based on the linearized theory of gravitational wave emission. The second is a typical bremsstrahlung angular pattern in the early period of emission at the wave zone, a consequence of the deceleration of the black holes as they coalesce; this pattern evolves to a quadrupole form for later times.Comment: 16 pages, 4 figures, to appear in Int. J. Modern Phys. D (2008

Análise da recente alta internacional dos preços das commodities alimentares: previsão e mudança estrutural.

Este artigo tem como objetivo analisar a alta observada entre 2007 e 2011 nos preços das commodities de alimentação em âmbito internacional, tendo como motivação os efeitos prejudiciais que a elevação dos preços desse tipo de produto causa à segurança alimentar mundial. Por meio do método de Box e Jenkins (1976), busca-se estudar o comportamento dos preços nos meses que completam o ano de 2011 e, utilizando-se a análise de quebra estrutural, procura-se comprovar a quebra estrutural no período de maior alta. O estudo permite verificar que existe uma tendência de alta nos preços dos alimentos e de mudança estrutural na base de formação deles, evidenciando a necessidade de políticas públicas, em âmbito internacional, que assistam ao problema

Post-warming culture with beta-mercaptoethanol does not alter embryo survival but improves the quality of in IVP bovine embryos post vitrification.

Abstracts of 36th Annual Meeting of the Brazilian Embryo Technology Society (SBTE)