535 research outputs found

    The CMB and the measure of the multiverse

    Full text link
    In the context of eternal inflation, cosmological predictions depend on the choice of measure to regulate the diverging spacetime volume. The spectrum of inflationary perturbations is no exception, as we demonstrate by comparing the predictions of the fat geodesic and causal patch measures. To highlight the effect of the measure---as opposed to any effects related to a possible landscape of vacua---we take the cosmological model, including the model of inflation, to be fixed. We also condition on the average CMB temperature accompanying the measurement. Both measures predict a 1-point expectation value for the gauge-invariant Newtonian potential, which takes the form of a (scale-dependent) monopole, in addition to a related contribution to the 3-point correlation function, with the detailed form of these quantities differing between the measures. However, for both measures both effects are well within cosmic variance. Our results make clear the theoretical relevance of the measure, and at the same time validate the standard inflationary predictions in the context of eternal inflation.Comment: 28 pages; v2: reference added, some clarification

    Connaissances, attitudes et pratiques de la population du Hodh El Gharbi (Mauritanie) face au virus de l’immunodéficience humaine(VIH).

    Get PDF
    Il s’agit d’une enquête transversale, descriptive et analytique menée au centre hospitalier d’Aïoun sur la période du 1er janvier au 31 mai 2013. L’objectif global de notre travail était de décrire les connaissances, attitudes et pratiques sur le VIH/SIDA des patients reçus en consultation pour une infection sexuellement transmissible (IST). De façon spécifique, notre travail visait à évaluer les comportements sexuels à risque d’infection par le VIH et l’acceptation du test de dépistage volontaire chez ces consultants. Le dépistage volontaire du VIH n’était pas gratuit. L’information était recueillie à partir d’un questionnaire auto rempli. En cinq mois, 167 patients ont consenti à participer à l’étude soit 15,84%. Le sex-ratio H/F était de 0,65 et l'âge moyen était de 30 ± 5 ans [15-45ans]. Plus de la moitié (58,1%) provenait du milieu rural. Parmi eux 89,2% étaient non instruits. Les connaissances générales sur les modes de transmission du VIH étaient erronées dans 94,6% des cas. Le préservatif n’avait jamais été utilisé par les enquêtés (91,6%). Le principal motif de consultation était les leucorrhées (45,5%) suivies des mictions douloureuses (22,2%). Le dépistage volontaire pour le VIH était effectué par 4,8% des enquêtés. Un lien statistiquement significatif a été retrouvé entre la connaissance des modes de transmission du VIH, l’âge, le sexe, la provenance, le niveau d’éducation scolaire, le manque d’information et l’absence d’utilisation du préservatif. Nos résultats ont révélé chez les consultants pour IST, des connaissances, attitudes et pratiques qui exposent à une grande vulnérabilité au VIH. A l'issue de ce travail, vu le lien étroit entre les IST et le VIH, nous recommandons le développement de stratégies globales de prévention (population générale) et ciblée (consultants IST) afin de réduire le risque d'infection par le VIH dans la région, en particulier chez les porteurs d'IST

    Stability and Antioxidant Activity of Hydro-Glyceric Extracts Obtained from Different Grape Seed Varieties Incorporated in Cosmetic Creams

    Get PDF
    Grape seeds are agro-industrial by-products, which if improperly managed, may be responsible for socioeconomic and environmental problems. Nevertheless, it is possible to effectively valorize them by means of extraction of the bioactive compounds, especially the antioxidant phenolic molecules, using a safe, green, and environmentally-friendly extractive medium (i.e., hydro-glyceric solution). In the present study, the extraction was performed using seeds from two Lebanese varieties, Obeidi and Asswad Karech, and three international varieties, Marselan, Syrah, and Cabernet Franc. The type and amount of phenolic compounds were identified by High-Performance Liquid Chromatography (HPLC). Marselan was the extract richer in catechins (132.99 +/- 9.81 mu g/g of dried matter), and it also contained a higher amount of phenolic compounds (49.08 +/- 0.03 mg of gallic acid equivalent/g of dry matter and 10.02 +/- 0.24 mg of proanthocyanidin content/g of dry matter). The antioxidant capacity of the extracts was assessed using three different colorimetric assays including 2,2-DiPhenyl-1-PicrylHydrazyl (DPPH), CUPRIC ion Reducing Antioxidant Capacity (CUPRAC), and Ferric Reducing Antioxidant Power (FRAP). As expected, Marselan exhibited the highest antioxidant activity; as well, the total phenolic and proanthocyanidin content were the highest. The stability of the Marselan extract incorporated into a commercial cream, was performed at three different temperatures (4, 25, and 50 degrees C), and four different concentrations (5, 4, 3, 2%), over a period of 4 months, using different methods such as centrifugation, Heat-Shock Cycles, pH, and viscosity. All Marselan hydro-glyceric extract formulations were proven to be stable over the entire 4 months, where the highest stability was achieved at 4 degrees C and the least at 50 degrees C. This study supports the suitability of the incorporation of phenolic extracts into commercial creams to enrich the cosmetic industry with effective, natural, and safe skincare products

    ALPS: the Arbitrary Linear Plasma Solver

    Get PDF
    The Arbitrary Linear Plasma Solver (ALPS) is a parallelised numerical code that solves the dispersion relation in a hot (even relativistic) magnetised plasma with an arbitrary number of particle species with arbitrary gyrotropic equilibrium distribution functions for any direction of wave propagation with respect to the background field. ALPS reads the background momentum distributions as tables of values on a (p⊥, pk) grid, where p⊥ and pk are the momentum coordinates in the directions perpendicular and parallel to the background magnetic field, respectively. We present the mathematical and numerical approach used by ALPS and introduce our algorithms for the handling of poles and the analytic continuation for the Landau contour integral. We then show test calculations of dispersion relations for a selection of stable and unstable configurations in Maxwellian, bi-Maxwellian, κ-distributed and Jüttner-distributed plasmas. These tests demonstrate that ALPS derives reliable plasma dispersion relations. ALPS will make it possible to determine the properties of waves and instabilities in the non-equilibrium plasmas that are frequently found in space, laboratory experiments and numerical simulations

    Acute febrile illness is associated with Rickettsia spp infection in dogs

    Get PDF
    BACKGROUND: Rickettsia conorii is transmitted by Rhipicephalus sanguineus ticks and causes Mediterranean Spotted Fever (MSF) in humans. Although dogs are considered the natural host of the vector, the clinical and epidemiological significance of R. conorii infection in dogs remains unclear. The aim of this prospective study was to investigate whether Rickettsia infection causes febrile illness in dogs living in areas endemic for human MSF. METHODS: Dogs from southern Italy with acute fever (n = 99) were compared with case–control dogs with normal body temperatures (n = 72). Serology and real-time PCR were performed for Rickettsia spp., Ehrlichia canis, Anaplasma phagocytophilum/A. platys and Leishmania infantum. Conventional PCR was performed for Babesia spp. and Hepatozoon spp. Acute and convalescent antibodies to R. conorii, E. canis and A. phagocytophilum were determined. RESULTS: The seroprevalence rates at first visit for R. conorii, E. canis, A. phagocytophilum and L. infantum were 44.8%, 48.5%, 37.8% and 17.6%, respectively. The seroconversion rates for R. conorii, E. canis and A. phagocytophilum were 20.7%, 14.3% and 8.8%, respectively. The molecular positive rates at first visit for Rickettsia spp., E. canis, A. phagocytophilum, A. platys, L. infantum, Babesia spp. and Hepatozoon spp. were 1.8%, 4.1%, 0%, 2.3%, 11.1%, 2.3% and 0.6%, respectively. Positive PCR for E. canis (7%), Rickettsia spp. (3%), Babesia spp. (4.0%) and Hepatozoon spp. (1.0%) were found only in febrile dogs. The DNA sequences obtained from Rickettsia and Babesia PCRs positive samples were 100% identical to the R. conorii and Babesia vogeli sequences in GenBank®, respectively. Febrile illness was statistically associated with acute and convalescent positive R. conorii antibodies, seroconversion to R. conorii, E. canis positive PCR, and positivity to any tick pathogen PCRs. Fourteen febrile dogs (31.8%) were diagnosed with Rickettsia spp. infection based on seroconversion and/or PCR while only six afebrile dogs (12.5%) seroconverted (P = 0.0248). The most common clinical findings of dogs with Rickettsia infection diagnosed by seroconversion and/or PCR were fever, myalgia, lameness, elevation of C-reactive protein, thrombocytopenia and hypoalbuminemia. CONCLUSIONS: This study demonstrates acute febrile illness associated with Rickettsia infection in dogs living in endemic areas of human MSF based on seroconversion alone or in combination with PCR

    Combination immunotherapy and active-specific tumor cell vaccination augments anti-cancer immunity in a mouse model of gastric cancer

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Active-specific immunotherapy used as an adjuvant therapeutic strategy is rather unexplored for cancers with poorly characterized tumor antigens like gastric cancer. The aim of this study was to augment a therapeutic immune response to a low immunogenic tumor cell line derived from a spontaneous gastric tumor of a CEA424-SV40 large T antigen (CEA424-SV40 TAg) transgenic mouse.</p> <p>Methods</p> <p>Mice were treated with a lymphodepleting dose of cyclophosphamide prior to reconstitution with syngeneic spleen cells and vaccination with a whole tumor cell vaccine combined with GM-CSF (a treatment strategy abbreviated as LRAST). Anti-tumor activity to subcutaneous tumor challenge was examined in a prophylactic as well as a therapeutic setting and compared to corresponding controls.</p> <p>Results</p> <p>LRAST enhances tumor-specific T cell responses and efficiently inhibits growth of subsequent transplanted tumor cells. In addition, LRAST tended to slow down growth of established tumors. The improved anti-tumor immune response was accompanied by a transient decrease in the frequency and absolute number of CD4<sup>+</sup>CD25<sup>+</sup>FoxP3<sup>+ </sup>T cells (Tregs).</p> <p>Conclusions</p> <p>Our data support the concept that whole tumor cell vaccination in a lymphodepleted and reconstituted host in combination with GM-CSF induces therapeutic tumor-specific T cells. However, the long-term efficacy of the treatment may be dampened by the recurrence of Tregs. Strategies to counteract suppressive immune mechanisms are required to further evaluate this therapeutic vaccination protocol.</p

    Investigating cooperation with robotic peers

    Get PDF
    We explored how people establish cooperation with robotic peers, by giving participants the chance to choose whether to cooperate or not with a more/less selfish robot, as well as a more or less interactive, in a more or less critical environment. We measured the participants' tendency to cooperate with the robot as well as their perception of anthropomorphism, trust and credibility through questionnaires. We found that cooperation in Human-Robot Interaction (HRI) follows the same rule of Human-Human Interaction (HHI), participants rewarded cooperation with cooperation, and punished selfishness with selfishness. We also discovered two specific robotic profiles capable of increasing cooperation, related to the payoff. A mute and non-interactive robot is preferred with a high payoff, while participants preferred a more human-behaving robot in conditions of low payoff. Taken together, these results suggest that proper cooperation in HRI is possible but is related to the complexity of the task

    TS-AMIR: a topology string alignment method for intensive rapid protein structure comparison

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>In structural biology, similarity analysis of protein structure is a crucial step in studying the relationship between proteins. Despite the considerable number of techniques that have been explored within the past two decades, the development of new alternative methods is still an active research area due to the need for high performance tools.</p> <p>Results</p> <p>In this paper, we present TS-AMIR, a Topology String Alignment Method for Intensive Rapid comparison of protein structures. The proposed method works in two stages: In the first stage, the method generates a topology string based on the geometric details of secondary structure elements, and then, utilizes an n-gram modelling technique over entropy concept to capture similarities in these strings. This initial correspondence map between secondary structure elements is submitted to the second stage in order to obtain the alignment at the residue level. Applying the Kabsch method, a heuristic step-by-step algorithm is adopted in the second stage to align the residues, resulting in an optimal rotation matrix and minimized RMSD. The performance of the method was assessed in different information retrieval tests and the results were compared with those of CE and TM-align, representing two geometrical tools, and YAKUSA, 3D-BLAST and SARST as three representatives of linear encoding schemes. It is shown that the method obtains a high running speed similar to that of the linear encoding schemes. In addition, the method runs about 800 and 7200 times faster than TM-align and CE respectively, while maintaining a competitive accuracy with TM-align and CE.</p> <p>Conclusions</p> <p>The experimental results demonstrate that linear encoding techniques are capable of reaching the same high degree of accuracy as that achieved by geometrical methods, while generally running hundreds of times faster than conventional programs.</p

    Vivax malaria in Mauritania includes infection of a Duffy-negative individual

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Duffy blood group polymorphisms are important in areas where <it>Plasmodium vivax </it>is present because this surface antigen is thought to act as a key receptor for this parasite. In the present study, Duffy blood group genotyping was performed in febrile uninfected and <it>P. vivax</it>-infected patients living in the city of Nouakchott, Mauritania.</p> <p>Methods</p> <p><it>Plasmodium vivax </it>was identified by real-time PCR. The Duffy blood group genotypes were determined by standard PCR followed by sequencing of the promoter region and exon 2 of the Duffy gene in 277 febrile individuals. Fisher's exact test was performed in order to assess the significance of variables.</p> <p>Results</p> <p>In the Moorish population, a high frequency of the <it>FYB<sup>ES</sup>/FYB<sup>ES </sup></it>genotype was observed in uninfected individuals (27.8%), whereas no <it>P. vivax</it>-infected patient had this genotype. This was followed by a high level of <it>FYA/FYB</it>, <it>FYB/FYB</it>, <it>FYB/FYB<sup>ES </sup></it>and <it>FYA/FYB<sup>ES </sup></it>genotype frequencies, both in the <it>P. vivax</it>-infected and uninfected patients. In other ethnic groups (Poular, Soninke, Wolof), only the <it>FYB<sup>ES</sup>/FYB<sup>ES </sup></it>genotype was found in uninfected patients, whereas the <it>FYA/FYB<sup>ES </sup></it>genotype was observed in two <it>P. vivax</it>-infected patients. In addition, one patient belonging to the Wolof ethnic group presented the <it>FYB<sup>ES</sup>/FYB<sup>ES </sup></it>genotype and was infected by <it>P. vivax</it>.</p> <p>Conclusions</p> <p>This study presents the Duffy blood group polymorphisms in Nouakchott City and demonstrates that in Mauritania, <it>P. vivax </it>is able to infect Duffy-negative patients. Further studies are necessary to identify the process that enables this Duffy-independent <it>P. vivax </it>invasion of human red blood cells.</p
    corecore