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

Sensory evaluation and cooking properties of macaroni at basis of brazil nut (Bertholetia excelsa) and peach palm fruit (Bactris gasipaes, Kunt) flours.

The Brazil nut tree, Bertholletia excelsa HBK, is explored throughout the Amazon region and its main characteristic is high content of lipids and proteins, they consist of sulfur amino acids of high biological value. The peach palm, Bactris gasipases, Kunth, is a native palm to the same region, that is grown for heart-of-palm extraction. Their fruits are mostly protein, vitamin A and fiber. The way of adding commercial value from co-products to Brazil nut processing is flour productian. That way the Brazil nut flour, for its high nutritional value and pleasant taste was used in macaroni production, along with peach palm fruit flour to improve the nutritianal properties of final product

Universal features and tail analysis of the order-parameter distribution of the two-dimensional Ising model: An entropic sampling Monte Carlo study

We present a numerical study of the order-parameter probability density function (PDF) of the square Ising model for lattices with linear sizes $L=80-140$. A recent efficient entropic sampling scheme, combining the Wang-Landau and broad histogram methods and based on the high-levels of the Wang-Landau process in dominant energy subspaces is employed. We find that for large lattices there exists a stable window of the scaled order-parameter in which the full ansatz including the pre-exponential factor for the tail regime of the universal PDF is well obeyed. This window is used to estimate the equation of state exponent and to observe the behavior of the universal constants implicit in the functional form of the universal PDF. The probability densities are used to estimate the universal Privman-Fisher coefficient and to investigate whether one could obtain reliable estimates of the universal constants controlling the asymptotic behavior of the tail regime.Comment: 24 pages, 5 figure

Production and characterization of Orpinomyces mutant xylanases with improved temperature and pH stabilities

The error-prone PCR technique has been widely used in order to obtain thermostable enzymes more suitable for industrial conditions. The Orpinomyces xynA mutant library allowed the selection of four thermostable mutants (M1-M4). Molecular dynamics (MD) predicted an N-terminal tail as being a destabilizing structural region and allowed further enhancing of the mutant xylanases thermostability. Thus, removal of the 27 amino acid residues enabled an increase in the enzyme half-life values (t1/2). However, besides the improved thermostability, the large enzyme production and high catalytic performance are also relevant for the biotechnological application of enzymes. During the mutant enzymes production in E. coli, the IPTG induction protocol allowed high expression levels of soluble and active xylanases. The mutant xylanases without the 27 amino acid residues showed improved thermostability and the shorter versions of M2 and M4 (named as SM2 and SM4) also presented a good performance in more extreme pH conditions

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

OntoEPFS: uma ontologia para experimentos em mapeamento digital de solos.

A descrição formal de experimentos para aquisição, tratamento, análises de dados, compartilhamento e reprodução dos resultados obtidos é fundamental para os cientistas envolvidos. Ontologias vêm sendo utilizadas para criar modelos formais para disseminação de informação e conhecimento. Este artigo apresenta uma ontologia para apoiar o Experimento de Predição de Informações de Fertilidades de Solos (OntoEPFS) em Mapeamento Digital de Solos (DSM). O EPFS se encontra em desenvolvimento na Empresa Brasileira de Pesquisa Agropecuária, no Centro Nacional de Pesquisa em Solos ? Embrapa Solos. A adoção dessa ontologia, por parte da Embrapa Solos, facilitará a descrição, a formalização e a disponibilização de conhecimentos sobre os experimentos realizados por esta unidade.SBIAgro 2009

Reversing resistance to tembotrione in an Amaranthus tuberculatus (var. rudis) population from Nebraska, USA with cytochrome P450 inhibitors

Background: A population of Amaranthus tuberculatus (var. rudis) was confirmed resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed a non-target-site resistance mechanism in this population. The main objective of this study was to explore the role of cytochrome P450 inhibitors in restoring the efficacy of HPPD-inhibitor herbicides on the HPPD-inhibitor resistant A. tuberculatus population from Nebraska, USA (HPPD-R). Background: A population of Amaranthus tuberculatus (var. rudis) was confirmed resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed a non-target-site resistance mechanism in this population. The main objective of this study was to explore the role of cytochrome P450 inhibitors in restoring the efficacy of HPPD-inhibitor herbicides on the HPPD-inhibitor resistant A. tuberculatus population from Nebraska, USA (HPPD-R). Results: Enhanced metabolism via cytochrome P450 enzymes is the mechanism of resistance in HPPD-R. Amitrole partially restored the activity of mesotrione, whereas malathion, amitrole, and piperonyl butoxide restored the activity of tembotrione and topramezone in HPPD-R. Although corn was injured through malathion followed by mesotrione application a week after treatment, the injury was transient, and the crop recovered. Includes supplementary file

A timeband framework for modelling real-time systems

Complex real-time systems must integrate physical processes with digital control, human operation and organisational structures. New scientific foundations are required for specifying, designing and implementing these systems. One key challenge is to cope with the wide range of time scales and dynamics inherent in such systems. To exploit the unique properties of time, with the aim of producing more dependable computer-based systems, it is desirable to explicitly identify distinct time bands in which the system is situated. Such a framework enables the temporal properties and associated dynamic behaviour of existing systems to be described and the requirements for new or modified systems to be specified. A system model based on a finite set of distinct time bands is motivated and developed in this paper