750 research outputs found

    Oxidation reactions of derivatives of cis-octalins promoted by thallium trinitrate (TTN)

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    The reaction of ten cis-octalins and cis-octalones with thallium trinitrate (TTN) leads to different products, depending mainly on the substitution pattern of the substrate. Functionalized cis-hydrindanes were obtained from the reaction of 1,2,3,4,4a,5,8,8a-octahydro-4a-methylnaphthalene and of 1,2,3,4,4a,5,8,8a-octahydro-4a,7-dimethylnaphthalene with TTN in acetonitrile, whereas a cyclic ether was formed treating 1,2,3,4,4a,5,8,8a-octahydro-6,8a-dimethylnaphthalen-1-ol with TTN in trimethylorthoformate (TMOF).FAPESPCNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

    Revisiting the S-matrix approach to the open superstring low energy effective lagrangian

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    The conventional S-matrix approach to the (tree level) open string low energy effective lagrangian assumes that, in order to obtain all its bosonic αN{\alpha'}^N order terms, it is necessary to know the open string (tree level) (N+2)(N+2)-point amplitude of massless bosons, at least expanded at that order in α\alpha'. In this work we clarify that the previous claim is indeed valid for the bosonic open string, but for the supersymmetric one the situation is much more better than that: there are constraints in the kinematical bosonic terms of the amplitude (probably due to Spacetime Supersymmetry) such that a much lower open superstring nn-point amplitude is needed to find all the αN{\alpha'}^N order terms. In this `revisited' S-matrix approach we have checked that, at least up to α4{\alpha'}^4 order, using these kinematical constraints and only the known open superstring 4-point amplitude, it is possible to determine all the bosonic terms of the low energy effective lagrangian. The sort of results that we obtain seem to agree completely with the ones achieved by the method of BPS configurations, proposed about ten years ago. By means of the KLT relations, our results can be mapped to the NS-NS sector of the low energy effective lagrangian of the type II string theories implying that there one can also find kinematical constraints in the NN-point amplitudes and that important informations can be inferred, at least up to α4{\alpha'}^4 order, by only using the (tree level) 4-point amplitude.Comment: 34 pages, 3 figure, Submitted on Aug 4, 2012, Published on Oct 15, 201

    High p_T Direct Photon and pi^0 Triggered Azimuthal Jet Correlations in sqrt(s)=200 GeV p+p Collisions

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    Correlations of charged hadrons of 1 < pT < 10 GeV/c with high pT direct photons and pi^ 0 mesons in the range 5 <pT < 15 GeV/c are used to study jet fragmentation in the photon+jet and di-jet channels, respectively. The magnitude of the partonic transverse momentum, kT, is obtained by comparing to a model incorporating a Gaussian kT smearing. The sensitivity of the associated charged hadron spectra to the underlying fragmentation function is tested and the data are compared to calculations using recent global fit results. The shape of the direct photon-associated hadron spectrum as well as its charge asymmetry are found to be consistent with a sample dominated by quark-gluon Compton scattering. No significant evidence of fragmentation photon correlated production is observed within experimental uncertainties.Comment: 431 authors, 18 pages, 18 figures, 4 tables, RevTeX-4. Submitted to Physical Review D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

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    Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

    Cervical lymph node metastasis in adenoid cystic carcinoma of the larynx: a collective international review

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    Adenoid cystic carcinoma (AdCC) of the head and neck is a well-recognized pathologic entity that rarely occurs in the larynx. Although the 5-year locoregional control rates are high, distant metastasis has a tendency to appear more than 5 years post treatment. Because AdCC of the larynx is uncommon, it is difficult to standardize a treatment protocol. One of the controversial points is the decision whether or not to perform an elective neck dissection on these patients. Because there is contradictory information about this issue, we have critically reviewed the literature from 1912 to 2015 on all reported cases of AdCC of the larynx in order to clarify this issue. During the most recent period of our review (1991-2015) with a more exact diagnosis of the tumor histology, 142 cases were observed of AdCC of the larynx, of which 91 patients had data pertaining to lymph node status. Eleven of the 91 patients (12.1%) had nodal metastasis and, based on this low proportion of patients, routine elective neck dissection is therefore not recommended

    Near real-time security system applied to SDN environments in IoT networks using convolutional neural network

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    [EN] The Internet of Things (IoT) paradigm brings new and promising possibilities for services and products. The heterogeneity of IoT devices highlights the inefficiency of traditional networks' structures to support their specific requirements due to their lack of flexibility. Thus, Software-defined Networking (SDN) is commonly associated with IoT since this architecture provides a more flexible and manageable network environment. As shown by recent events, IoT devices may be used for large scale Distributed Denial of Service (DDoS) attacks due to their lack of security. This kind of attack is commonly detected and mitigated at the destination-end network but, due to the massive volume of information that IoT botnets generate, this approach is becoming impracticable. We propose in this paper a near real-time SDN security system that both prevents DDoS attacks on the source-end network and protects the sources SDN controller against traffic impairment. For this, we apply and test a Convolutional Neural Network (CNN) for DDoS detection, and describe how the system could mitigate the detected attacks. The performance outcomes were performed in two test scenarios, and the results pointed out that the proposed SDN security system is promising against next-generation DDoS attacks. (C) 2020 Published by Elsevier Ltd.This study was financed in part by the National Council for Scientific and Technological Development (CNPq) of Brazil under Grants 310668/2019-0 and 309335/2017-5; by the Ministerio de Economia y Competitividad in the "Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia, Subprograma Estatal de Generacion de Conocimiento" within the project under Grant TIN2017-84802-C2-1-P; by FCT/MCTES through national funds and when applicable co-funded EU funds under the Project UIDB/EEA/50008/2020; and by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) by the granting of a scholarship through the "Programa de Doutorado Sanduche no Exterior (PDSE) 2019". Finally, this work was supported by Federal University of Parana(UFPR) under Project Banpesq/2014016797.De Assis, MVO.; Carvalho, LF.; Rodrigues, JJPC.; Lloret, J.; Proenca Jr, ML. (2020). Near real-time security system applied to SDN environments in IoT networks using convolutional neural network. Computers & Electrical Engineering. 86:1-16. https://doi.org/10.1016/j.compeleceng.2020.1067381168

    Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter

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    Azimuthal angle \Delta\phi correlations are presented for charged hadrons from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing p_T, the away-side distribution evolves from a broad to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side can be divided into a partially suppressed "head" region centered at Delta\phi ~ \pi, and an enhanced "shoulder" region centered at Delta\phi ~ \pi +/- 1.1. The p_T spectrum for the "head" region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the "shoulder" region is independent of centrality and trigger p_T, which offers constraints on energy transport mechanisms and suggests that the "shoulder" region contains the medium response to energetic jets.Comment: 420 authors from 58 institutions, 6 pages, 4 figures. Submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Intracranial hypertension

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    A relação entre o conteúdo da caixa intracraniana e o seu volume determina a pressão intracraniana (PIC), que tem como referência a pressão atmosférica. Em condições normais, a pressão intracraniana tem flutuações determinadas pelos ciclos respiratório e cardíaco. Várias doenças determinam o aumento da pressão intracraniana, sendo a mais freqüente o traumatismo craniencefálico. Para o diagnóstico da hipertensão intracraniana (HIC) deve-se valorizar o quadro clínico, constituído de cefaléia, vômitos e papiledema. Dos exames subsidiários, os mais importantes são os métodos de imagem principalmente Tomografia Computadorizada (TC) e Ressonância Nuclear Magnética (RNM). Para os casos graves de HIC, o ideal durante o tratamento é que a PIC esteja monitorizada. Diversas modalidades podem ser utilizadas, como a hipocapnia induzida pela hiperventilação, os diuréticos osmóticos, a hipotermia e cuidados especiais no tratamento geral dos pacientes.The relation between the volume of the brain and the skull determines the intracranial pressure, that has as reference the atmospheric pressure. In normal conditions the intracranial pressure has oscillations determined by the breathing and heart cycles. Several pathologies determine the increase of the intracranial pressure, the most frequent the head trauma. Should be valued for the diagnosis of the intracranial hypertension (ICH) the clinical picture of headache, vomiting and papilledema. The most important subsidiary exams are the image methods mainly the Computed Tomography (CT) and the Magnetic Resonance Imaging (MRI). Monitorization of the intracranial pressure is important for severe cases of ICH. Several therapeutic modalities can ben used, as hypocarbia induced by hyperventilation, osmotics diuretics, barbiturates, hypothermia and special general measures with the patient
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