2,119 research outputs found

    Radiation-Induced Error Criticality in Modern HPC Parallel Accelerators

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    In this paper, we evaluate the error criticality of radiation-induced errors on modern High-Performance Computing (HPC) accelerators (Intel Xeon Phi and NVIDIA K40) through a dedicated set of metrics. We show that, as long as imprecise computing is concerned, the simple mismatch detection is not sufficient to evaluate and compare the radiation sensitivity of HPC devices and algorithms. Our analysis quantifies and qualifies radiation effects on applications’ output correlating the number of corrupted elements with their spatial locality. Also, we provide the mean relative error (dataset-wise) to evaluate radiation-induced error magnitude. We apply the selected metrics to experimental results obtained in various radiation test campaigns for a total of more than 400 hours of beam time per device. The amount of data we gathered allows us to evaluate the error criticality of a representative set of algorithms from HPC suites. Additionally, based on the characteristics of the tested algorithms, we draw generic reliability conclusions for broader classes of codes. We show that arithmetic operations are less critical for the K40, while Xeon Phi is more reliable when executing particles interactions solved through Finite Difference Methods. Finally, iterative stencil operations seem the most reliable on both architectures.This work was supported by the STIC-AmSud/CAPES scientific cooperation program under the EnergySFE research project grant 99999.007556/2015-02, EU H2020 Programme, and MCTI/RNP-Brazil under the HPC4E Project, grant agreement n° 689772. Tested K40 boards were donated thanks to Steve Keckler, Timothy Tsai, and Siva Hari from NVIDIA.Postprint (author's final draft

    Serum 25-hydroxyvitamin D levels in patients with Granulomatosis with Polyangiitis: association with respiratory infection

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    OBJECTIVES: To determine the possible association of serum 25-hydroxyvitamin D (25OHD) levels with disease activity and respiratory infection in granulomatosis with polyangiitis patients during two different periods: winter/spring and summer/autumn. METHODS: Thirty-two granulomatosis with polyangiitis patients were evaluated in the winter/spring, and the same patients (except 5) were evaluated in summer/autumn (n=27). The 25OHD levels were measured by radioimmunoassay. Disease activity was assessed by the Birmingham Vasculitis Activity Score Modified for Wegener’s Granulomatosis (BVAS/WG) and antineutrophil cytoplasmic antibody (ANCA) positivity. Respiratory infection was defined according the Centers for Disease Control and Prevention criteria. RESULTS: 25OHD levels were lower among patients in winter/spring than in summer/autumn (32.31±13.10 vs. 38.98±10.97 ng/mL, p=0.04). Seven patients met the criteria for respiratory infection: 5 in winter/spring and 2 in summer/autumn. Patients with respiratory infection presented lower 25OHD levels than those without infection (25.15±11.70 vs. 36.73±12.08 ng/mL, p=0.02). A higher frequency of low vitamin D levels (25OH

    Self-Reported Dental Fear among Dental Students and Their Patients

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    The aim of the present study was to compare self-reported dental fear among dental students and patients at a School of Dentistry in Belo Horizonte, Brazil. Eighty students ranging in age from 20 to 29 years and 80 patients ranging in age from 18 to 65 years participated in the study. A self-administered pre-tested questionnaire consisting of 13 items was used for data acquisition. The city of Belo Horizonte Social Vulnerability Index (SVI) was employed for socioeconomic classification. The chi-square test and binary and multinomial logistic regression were employed in the statistical analysis, with the significance level set at 0.05. The majority of dental students (76.5%) sought the dentist for the first time for a routine exam, while patients (77.3%) mostly sought a dentist for the treatment of dental pain. Dental fear was more prevalent among the patients (72.5%) than the students (27.5%). A total of 47.1% of the students and 52.9% of the patients reported having had negative dental experiences in childhood. The logistic model revealed an association between dental fear and a pain-related experience (OR: 1.8; 95%CI: 1.3–2.6). Patients were more prone to dental fear (OR: 2.2; 95%CI: 1.0–5.0). Although at different percentages, both students and patients experienced dental fear. Current patient with previous experience of dental pain had more dental fear

    Solution and Asymptotic Behavior for a Nonlocal Coupled System of Reaction-Diffusion

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    This paper concerns with existence, uniqueness and asymptotic behavior of the solutions for a nonlocal coupled system of reaction-diffusion. We prove the existence and uniqueness of weak solutions by the Faedo-Galerkin method and exponential decay of solutions by the classic energy method. We improve the results obtained by Chipot-Lovato and Menezes for coupled systems. A numerical scheme is presented

    Fresh inflation and decoherence of super Hubble fluctuations

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    I study a stochastic approach to the recently introduced fresh inflation model for super Hubble scales. I find that the state loses its coherence at the end of the fresh inflationary period as a consequence of the damping of the interference function in the reduced density matrix. This fact should be a consequence of a) the relative evolutions of both the scale factor and the horizon and b) the additional thermal and dissipative effects. This implies a relevant difference with respect to supercooled inflationary scenarios which require a very rapid expansion of the scale factor to give the decoherence of super Hubble fluctuations.Comment: version with minor changes. To appear in Phys. Rev.

    The role of Tyr(605) and Ala(607) of thimet oligopeptidase and Tyr(606) and Gly(608) of neurolysin in substrate hydrolysis and inhibitor binding

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    The physicochemical properties of TOP (thimet oligopeptidase) and NEL (neurolysin) and their hydrolytic activities towards the FRET (fluorescence resonance energy transfer) peptide series AbzGFSXFRQ-EDDnp [where Abz is o-aminobenzoyl; X = Ala, Ile, Leu, Phe, Tyr, Trp, Ser, Gln, Glu, His, Arg or Pro; and EDDnp is N-(2,4-dinitrophenyl)-ethylenediamine] were compared with those of site-mutated analogues. Mutations at Tyr(605) and Ala(607) in TOP and at Tyr(606) and Gly(608) in NEL did not affect the overall folding of the two peptidases, as indicated by their thermal stability, CD analysis and the pH-dependence of the intrinsic fluorescence of the protein. the kinetic parameters for the hydrolysis of substrates with systematic variations at position P-1 showed that Tyr(605) and Tyr(606) of TOP and NEL respectively, played a role in subsite S-1. Ala(607) of TOP and Gly(608) of NEL contributed to the flexibility of the loops formed by residues 600-612 (GHLAGGYDGQYYG; one-letter amino acid codes used) in NEL and 599-611 (GHLAGGYDAQYYG; one-letter amino acid codes used) in TOP contributing to the distinct substrate specificities, particularly with an isoleucine residue at P-1. TOP Y605A was inhibited less efficiently by JA-2 {N-[1-(R,S)-carboxy-3-phenylpropyl]Ala-Aib-Tyr-p-aminobenzoate}, which suggested that the aromatic ring of Ty,105 was an important anchor for its interaction with wild-type TOP. the hydroxy groups of Tyr 605 and Tyr.. did not contribute to the pH-activity profiles, since the pKs obtained in the assays of mutants TOP Y605F and NEL Y606F were similar to those of wild-type peptidases. However, the pH-k(cat)/K-m dependence curve of TOP Y605A differed from that of wild-type TOP and from TOP Y606F. These results provide insights into the residues involved in the substrate specificities of TOP and NEL and how they select cytosolic peptides for hydrolysis.Universidade Federal de SĂŁo Paulo, Dept Biofis, BR-04044020 SĂŁo Paulo, BrazilInst Butantan, Lab Especial Toxinol Aplicada, CAT, CEPID, BR-05467010 SĂŁo Paulo, BrazilUniv SĂŁo Paulo, Inst Ciencias Biomed, Dept Biol Celular & Desenvolvimento, Programa Biol Celular, BR-05508900 SĂŁo Paulo, BrazilUniv SĂŁo Paulo, Lab Neurociencias, BR-03071000 SĂŁo Paulo, BrazilUniv Mogi das Cruzes, CIIB, BR-08780911 Mogi Das Cruzes, SP, BrazilUniversidade Federal de SĂŁo Paulo, Dept Biofis, BR-04044020 SĂŁo Paulo, BrazilWeb of Scienc

    Overview of the Morphology of Neotropical Termite Workers: History and Practice

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    This contribution deals with the worker caste of the Neotropical termite fauna. It is a compilation of present knowledge about the morphology of pseudergates and workers, including the literature discussing the origin and evolution of this caste, the terminology used in the different taxonomic groups, and the techniques used to study these individuals, especially examination of the gut, mandibles, legs, and nota. In order to assist in identifying workers, it includes a key for the families that occur in the Neotropical Region and a characterization of workers of all families, especially the subfamilies of Termitidae, with descriptions and illustrations of diagnostic morphological features of genera. We point out advances and gaps in knowledge, as well as directions for future research

    The activation of α1-adrenoceptors is implicated in the antidepressant-like effect of creatine in the tail suspension test

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    AbstractThe antidepressant-like activity of creatine in the tail suspension test (TST) was demonstrated previously by our group. In this study we investigated the involvement of the noradrenergic system in the antidepressant-like effect of creatine in the mouse TST. In the first set of experiments, creatine administered by i.c.v. route (1Όg/site) decreased the immobility time in the TST, suggesting the central effect of this compound. The anti-immobility effect of peripheral administration of creatine (1mg/kg, p.o.) was prevented by the pretreatment of mice with α-methyl-p-tyrosine (100mg/kg, i.p., inhibitor of tyrosine hydroxylase), prazosin (1mg/kg, i.p., α1-adrenoceptor antagonist), but not by yohimbine (1mg/kg, i.p., α2-adrenoceptor antagonist). Creatine (0.01mg/kg, subeffective dose) in combination with subeffective doses of amitriptyline (1mg/kg, p.o., tricyclic antidepressant), imipramine (0.1mg/kg, p.o., tricyclic antidepressant), reboxetine (2mg/kg, p.o., selective noradrenaline reuptake inhibitor) or phenylephrine (0.4Όg/site, i.c.v., α1-adrenoceptor agonist) reduced the immobility time in the TST as compared with either drug alone. These results indicate that the antidepressant-like effect of creatine is likely mediated by an activation of α1-adrenoceptor and that creatine produces synergistic effects in the TST with antidepressants that modulate noradrenaline transporter, suggesting that an improvement in the response to the antidepressant therapy may occur when creatine is combined with these antidepressants. Furthermore, the synergistic effect of creatine (0.01mg/kg, p.o.) and reboxetine (2mg/kg, p.o.) combination was abolished by the α1-adrenoceptor antagonist prazosin, indicating that the antidepressant-like effect of combined therapy is likely mediated by an activation of α1-adrenoceptor
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