995 research outputs found

    JA-trie: Entropy-based packet classification

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    Any improvement in packet classification performance is crucial to ensure Internet functions continue to track the ever-increasing link capacities. Packet classification is the foundation of many Internet functions: from fundamental packet-forwarding to advanced features such as Quality of Service en-forcement, monitoring and security functions. This work proposes a novel trie-based classification algorithm, named Jump-Ahead Trie (JA-trie), utilizing an entropy-based pre-processing phase and a novel approach to wildcard matching. Through extensive experimental tests, we demonstrate that our proposed algorithm is able to outperform a range of state-of-the-art classification algorithms.This work was jointly supported by the EPSRC INTERNET Project EP/H040536/1, by the National Science Foundation under Grant No. CNS-0855268, and by the MIUR project GreenNet (FIRB 2010).This is the accepted manuscript. The final version is available at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6900878

    Hylotrupes bajulus (L.) (Col., Cerambycidae): nutrition and attacked material

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    Hylotrupes bajulus, attacks softwood utilising the cellulose contained in wood walls as food. The fibre is digested in variable percentages, depending on the type of analysis, 20 to 48% and, according to some authors, without the assistance of intestinal symbiotic microorganisms. Furthermore, there is published work referring to Hylotrupes, concluding that "starch” … “plays no role in the nutrition of the larvae". Nevertheless, considering that attacks of this species decrease with wood seasoning increasing and having been demonstrated, and that “lignin degradation products of spruce wood do not influence larvae development”, it is possible to suppose that cell walls alone are not sufficient to feed this wood boring species. Furthermore, Hylotrupes larvae have chisel shaped mandibles, similar to those of powder post beetle larvae that feed on starch and need to pulverise the wood to access the cellular content. Preliminary research suggests an utilization of wood fibre as well as of starch by larvae of H. bajulus. Therefore, the purpose of this research is to test the degree of digestion of wood fibre from different sources (sapwood or heartwood) and the possible role of symbiotic microorganisms. Larvae of H. bajulus were grown on synthetic diets made of purified wood fibre and/or starch as main components supplied with mineral and vitamin. Substrates and frass were analysed for fibre fractions, starch and acid insoluble ash, the latter used as an indigestible marker. Larvae purified DNA was analysed by means of metagenomics approaches carried out by direct retrieval and analysis of 16S rRNA gene sequences free of cultural bias in order to discover the bacterial diversity from larva alimentary channel alone. Larvae of H. bajulus seem be able to digest either fibre or starch, and a role for symbiotic bacteria is supposed. Keywords: Cellulose, Starch, Frass, Mouth apparatus, Mandibl

    Thermodynamic and Kinetic Stabilities of Al(III) Complexes with N2O3 Pentadentate Ligands

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    : Al(III) complexes have been recently investigated for their potential use in imaging with positron emission tomography (PET) by formation of ternary complexes with the radioisotope fluorine-18 (18F). Although the derivatives of 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) are the most applied chelators for [Al18F]2+ labelling and (pre)clinical PET imaging, non-macrocyclic, semi-rigid pentadentate chelators having two N- and three O-donor atoms such as RESCA1 and AMPDA-HB have been proposed with the aim to allow room temperature labelling of temperature-sensitive biomolecules. The paucity of stability data on Al(III) complexes used for PET imaging instigated a complete thermodynamic and kinetic solution study on Al(III) complexes with aminomethylpiperidine (AMP) derivatives AMPTA and AMPDA-HB and the comparison with a RESCA1-like chelator CD3A-Bn (trans-1,2-diaminocyclohexane-N-benzyl-N,N',N'-triacetic acid). The stability constant of [Al(AMPDA-HB)] is about four orders of magnitude higher than that of [Al(AMPTA)] and [Al(CD3A-Bn)], highlighting the greater affinity of phenolates with respect to acetate O-donors. On the other hand, the kinetic inertness of the complexes, determined by following the Cu2+-mediated transmetallation reactions in the 7.5-10.5 pH range, resulted in a spontaneous and hydroxide-assisted dissociation slightly faster for [Al(AMPTA)] than for the other two complexes (t1/2 = 4.5 h for [Al(AMPTA)], 12.4 h for [Al(AMPDA-HB)], and 24.1 h for [Al(CD3A-Bn)] at pH 7.4 and 25 °C). Finally, the [AlF]2+ ternary complexes were prepared and their stability in reconstituted human serum was determined by 19F NMR experiments

    Animal models of hepatocellular carcinoma prevention

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    Hepatocellular carcinoma (HCC) is a deadly disease and therapeutic efficacy in advanced HCC is limited. Since progression of chronic liver disease to HCC involves a long latency period of a few decades, a significant window of therapeutic opportunities exists for prevention of HCC and improve patient prognosis. Nonetheless, there has been no clinical advancement in instituting HCC chemopreventive strategies. Some of the major challenges are heterogenous genetic aberrations of HCC, significant modulation of tumor microenvironment and incomplete understanding of HCC tumorigenesis. To this end, animal models of HCC are valuable tools to evaluate biology of tumor initiation and progression with specific insight into molecular and genetic mechanisms involved. In this review, we describe various animal models of HCC that facilitate effective ways to study therapeutic prevention strategies that have translational potential to be evaluated in a clinical context © 2019 by the authors. Licensee MDPI, Basel, Switzerland

    Intermediate-mass black holes and ultraluminous X-ray sources in the Cartwheel ring galaxy

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    Chandra and XMM-Newton observations of the Cartwheel galaxy show ∼17 bright X-ray sources (≳5 × 1038erg s−1), all within the gas-rich outer ring. We explore the hypothesis that these X-ray sources are powered by intermediate-mass black holes (IMBHs) accreting gas or undergoing mass transfer from a stellar companion. To this purpose, we run N-body/smoothed particle hydrodynamics simulations of the galaxy interaction which might have led to the formation of Cartwheel, tracking the dynamical evolution of two different IMBH populations: halo and disc IMBHs. Halo IMBHs cannot account for the observed X-ray sources, as only a few of them cross the outer ring. Instead, more than half of the disc IMBHs are pulled in the outer ring as a consequence of the galaxy collision. However, also in the case of disc IMBHs, accretion from surrounding gas clouds cannot account for the high luminosities of the observed sources. Finally, more than 500 disc IMBHs are required to produce ≲15 X-ray sources via mass transfer from very young stellar companions. Such number of IMBHs is very large and implies extreme assumptions. Thus, the hypothesis that all the observed X-ray sources in Cartwheel are associated with IMBHs is hardly consistent with our simulations, even if it is still possible that IMBHs account for the few (≲1-5) brightest ultraluminous X-ray source
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