41 research outputs found

    Dual charges for AdS spacetimes and the first law of black hole mechanics

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    ENTRAP and its potential interaction with European networks

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    AbstractENTRAP comprises a pan-European cooperation of leading scientific institutions and regulatory bodies in the field of nuclear-waste characterization and its quality assurance for the safe disposal of radioactive waste. Here, the scope of this cooperation is presented and explained and links or interfaces for a potential collaboration with partners fulfilling tasks of IDG-TP are pursued

    Recent acquisition of Helicobacter pylori by Baka Pygmies

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    Both anatomically modern humans and the gastric pathogen Helicobacter pylori originated in Africa, and both species have been associated for at least 100,000 years. Seven geographically distinct H. pylori populations exist, three of which are indigenous to Africa: hpAfrica1, hpAfrica2, and hpNEAfrica. The oldest and most divergent population, hpAfrica2, evolved within San hunter-gatherers, who represent one of the deepest branches of the human population tree. Anticipating the presence of ancient H. pylori lineages within all hunter-gatherer populations, we investigated the prevalence and population structure of H. pylori within Baka Pygmies in Cameroon. Gastric biopsies were obtained by esophagogastroduodenoscopy from 77 Baka from two geographically separated populations, and from 101 non-Baka individuals from neighboring agriculturalist populations, and subsequently cultured for H. pylori. Unexpectedly, Baka Pygmies showed a significantly lower H. pylori infection rate (20.8%) than non-Baka (80.2%). We generated multilocus haplotypes for each H. pylori isolate by DNA sequencing, but were not able to identify Baka-specific lineages, and most isolates in our sample were assigned to hpNEAfrica or hpAfrica1. The population hpNEAfrica, a marker for the expansion of the Nilo-Saharan language family, was divided into East African and Central West African subpopulations. Similarly, a new hpAfrica1 subpopulation, identified mainly among Cameroonians, supports eastern and western expansions of Bantu languages. An age-structured transmission model shows that the low H. pylori prevalence among Baka Pygmies is achievable within the timeframe of a few hundred years and suggests that demographic factors such as small population size and unusually low life expectancy can lead to the eradication of H. pylori from individual human populations. The Baka were thus either H. pylori-free or lost their ancient lineages during past demographic fluctuations. Using coalescent simulations and phylogenetic inference, we show that Baka almost certainly acquired their extant H. pylori through secondary contact with their agriculturalist neighbors

    Depletion of Dendritic Cells Enhances Innate Anti-Bacterial Host Defense through Modulation of Phagocyte Homeostasis

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    Dendritic cells (DCs) as professional antigen-presenting cells play an important role in the initiation and modulation of the adaptive immune response. However, their role in the innate immune response against bacterial infections is not completely defined. Here we have analyzed the role of DCs and their impact on the innate anti-bacterial host defense in an experimental infection model of Yersinia enterocolitica (Ye). We used CD11c-diphtheria toxin (DT) mice to deplete DCs prior to severe infection with Ye. DC depletion significantly increased animal survival after Ye infection. The bacterial load in the spleen of DC-depleted mice was significantly lower than that of control mice throughout the infection. DC depletion was accompanied by an increase in the serum levels of CXCL1, G-CSF, IL-1α, and CCL2 and an increase in the numbers of splenic phagocytes. Functionally, splenocytes from DC-depleted mice exhibited an increased bacterial killing capacity compared to splenocytes from control mice. Cellular studies further showed that this was due to an increased production of reactive oxygen species (ROS) by neutrophils. Adoptive transfer of neutrophils from DC-depleted mice into control mice prior to Ye infection reduced the bacterial load to the level of Ye-infected DC-depleted mice, suggesting that the increased number of phagocytes with additional ROS production account for the decreased bacterial load. Furthermore, after incubation with serum from DC-depleted mice splenocytes from control mice increased their bacterial killing capacity, most likely due to enhanced ROS production by neutrophils, indicating that serum factors from DC-depleted mice account for this effect. In summary, we could show that DC depletion triggers phagocyte accumulation in the spleen and enhances their anti-bacterial killing capacity upon bacterial infection

    The M1 angular moments model in a moving reference frame for rarefied gas dynamics applications

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    In the present work the M1 angular moments model in a moving reference frame is presented for rarefied gas dynamics applications. First of all, the derivation of the angular M1 moments model in the particles mean velocity frame is introduced. The choice of the mean velocity framework in order to enforce the Galilean invariance property of the model is highlighted. In addition, it is shown that the model rewritten in terms of the entropic variables is Friedrichs-symmetric. Also, the derivation of the associated conservation laws and the zero mean velocity condition are detailed. Secondly, a suitable numerical scheme, preserving the realisable requirement of the numerical solution for the angular M1 moments model in the mean velocity frame is proposed. Thirdly, some numerical results obtained considering several test cases in different collisional regimes are displayed

    The M1 angular moments model in a moving reference frame for rarefied gas dynamics applications

    No full text
    In the present work the M1 angular moments model in a moving reference frame is presented for rarefied gas dynamics applications. First of all, the derivation of the angular M1 moments model in the particles mean velocity frame is introduced. The choice of the mean velocity framework in order to enforce the Galilean invariance property of the model is highlighted. In addition, it is shown that the model rewritten in terms of the entropic variables is Friedrichs-symmetric. Also, the derivation of the associated conservation laws and the zero mean velocity condition are detailed. Secondly, a suitable numerical scheme, preserving the realisable requirement of the numerical solution for the angular M1 moments model in the mean velocity frame is proposed. Thirdly, some numerical results obtained considering several test cases in different collisional regimes are displayed

    The M1 angular moments model in a moving reference frame for rarefied gas dynamics applications

    No full text
    In the present work the M1 angular moments model in a moving reference frame is presented for rarefied gas dynamics applications. First of all, the derivation of the angular M1 moments model in the particles mean velocity frame is introduced. The choice of the mean velocity framework in order to enforce the Galilean invariance property of the model is highlighted. In addition, it is shown that the model rewritten in terms of the entropic variables is Friedrichs-symmetric. Also, the derivation of the associated conservation laws and the zero mean velocity condition are detailed. Secondly, a suitable numerical scheme, preserving the realisable requirement of the numerical solution for the angular M1 moments model in the mean velocity frame is proposed. Thirdly, some numerical results obtained considering several test cases in different collisional regimes are displayed

    Numerical Resolution of a Three Temperature Plasma Model

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    THE M 1 ANGULAR MOMENTS MODEL IN A MOVING REFERENCE FRAME FOR RAREFIED GAS DYNAMICS APPLICATIONS

    No full text
    In the present work the M 1 angular moments model in a moving reference frame is presented for rarefied gas dynamics applications. First of all, the derivation of the angular M 1 moments model in the particles mean velocity frame is introduced. The choice of the mean velocity framework in order to enforce the Galilean invariance property of the model is highlighted. In addition , it is shown that the model rewritten in terms of the entropic variables is Friedrichs-symmetric. Also, the derivation of the associated conservation laws and the zero mean velocity condition are detailed. Secondly, a suitable numerical scheme, preserving the realisable requirement of the numerical solution for the angular M 1 moments model in the mean velocity frame is proposed. Thirdly, some numerical results obtained considering several test cases in different collisional regimes are displayed
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