6 resultados para low-rate DDoS attacks

em University of Queensland eSpace - Australia


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Manual curation has long been held to be the gold standard for functional annotation of DNA sequence. Our experience with the annotation of more than 20,000 full-length cDNA sequences revealed problems with this approach, including inaccurate and inconsistent assignment of gene names, as well as many good assignments that were difficult to reproduce using only computational methods. For the FANTOM2 annotation of more than 60,000 cDNA clones, we developed a number of methods and tools to circumvent some of these problems, including an automated annotation pipeline that provides high-quality preliminary annotation for each sequence by introducing an uninformative filter that eliminates uninformative annotations, controlled vocabularies to accurately reflect both the functional assignments and the evidence supporting them, and a highly refined, Web-based manual annotation tool that allows users to view a wide array of sequence analyses and to assign gene names and putative functions using a consistent nomenclature. The ultimate utility of our approach is reflected in the low rate of reassignment of automated assignments by manual curation. Based on these results, we propose a new standard for large-scale annotation, in which the initial automated annotations are manually investigated and then computational methods are iteratively modified and improved based on the results of manual curation.

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The pumping characteristics of four Australian honey samples were investigated in a straight pipe. Six flow rates (100-500 kg h(-1)) were studied at three temperatures (35-50degreesC). The pressure loss increased with an increase in the length of the pipe, as the low rate was increased and as the temperature was reduced. In the 25.4 mm-pipe, the Reynolds number ranged from 0.2-32.0 and are substantially less than the critica value (2040-2180) for laminar condition in the system. The relationship between the wall shear stress and shear rate approximated power-law behaviour, and the power-law index was not significantly (p>0.05) different from 1.0. The honey samples exhibited Newtonian behaviour at all the temperatures and this was confirmed by rheometric studies using Couette geometry. A friction chart was generated independent of temperature and the type of honey. An equation was developed to predict the pressure loss of the honey in a typical pipeline at any temperature once the viscosity-temperature relationship had been established.

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Single male sexually selected traits have been found to exhibit substantial genetic variance, even though natural and sexual selection are predicted to deplete genetic variance in these traits. We tested whether genetic variance in multiple male display traits of Drosophila serrata was maintained under field conditions. A breeding design involving 300 field-reared males and their laboratory-reared offspring allowed the estimation of the genetic variance-covariance matrix for six male cuticular hydrocarbons (CHCs) under field conditions. Despite individual CHCs displaying substantial genetic variance under field conditions, the vast majority of genetic variance in CHCs was not closely associated with the direction of sexual selection measured on field phenotypes. Relative concentrations of three CHCs correlated positively with body size in the field, but not under laboratory conditions, suggesting condition-dependent expression of CHCs under field conditions. Therefore condition dependence may not maintain genetic variance in preferred combinations of male CHCs under field conditions, suggesting that the large mutational target supplied by the evolution of condition dependence may not provide a solution to the lek paradox in this species. Sustained sexual selection may be adequate to deplete genetic variance in the direction of selection, perhaps as a consequence of the low rate of favorable mutations expected in multiple trait systems.

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Ketol-acid reductoisomerase (EC 1.1.1.86) catalyses the second reaction in the biosynthesis of the branched-chain amino acids. The reaction catalyzed consists of two stages, the first of which is an alkyl migration from one carbon atom to its neighbour. The likely transition state is therefore a cyclopropane derivative, and cyclopropane-1,1-dicarboxylate(CPD) has been reported to inhibit the Escherichia coli enzyme. In addition, this compound causes the accumulation of the substrate of ketol-acid reductoisomerase in plants. Here, we investigate the inhibition of the purified rice enzyme. The cDNA was cloned, and the recombinant protein was expressed in E. coli, purified and characterized kinetically. The purified enzyme is strongly inhibited by cyclopropane-1,1-dicarboxylate, with an inhibition constant of 90 nM. The inhibition is time-dependent and this is due to the low rate constants for formation (2.63 X 10(5) M-1 min(-1)) and dissociation (2.37 x 10(-2) min(-1)) of the enzyme-inhibitor complex. Other cyclopropane derivatives are much weaker inhibitors while dimethylmalonate is moderately effective. (c) 2004 Elsevier Ireland Ltd. All rights reserved.