1,318 research outputs found
Activation profile of Mycobacterium tuberculosis-specific CD4+ T cells reflects disease activity, irrespective of HIV status
Theoretical tools for atom laser beam propagation
We present a theoretical model for the propagation of non self-interacting
atom laser beams. We start from a general propagation integral equation, and we
use the same approximations as in photon optics to derive tools to calculate
the atom laser beam propagation. We discuss the approximations that allow to
reduce the general equation whether to a Fresnel-Kirchhoff integral calculated
by using the stationary phase method, or to the eikonal. Within the paraxial
approximation, we also introduce the ABCD matrices formalism and the beam
quality factor. As an example, we apply these tools to analyse the recent
experiment by Riou et al. [Phys. Rev. Lett. 96, 070404 (2006)]
Coûts environnementaux du développement périurbain : impact des configurations urbaines et des choix résidentiels
[Departement_IRSTEA]Territoires [TR1_IRSTEA]DTAM [Axe_IRSTEA]DTAM1-REPRO [Axe_IRSTEA]DTAM-QT1-INEGALITESCe projet de recherche part du constat que la littĂ©rature existante sur la durabilitĂ© des espaces pĂ©riurbains n'a pas apportĂ© de rĂ©ponse sur deux points particuliers. En premier lieu, la question du transport est gĂ©nĂ©ralement considĂ©rĂ©e du seul point de vue du transport de personnes, dans une optique d'Ă©quilibre partiel dans laquelle le transport des biens produits et consommĂ©s dans la ville n'est pas pris en compte. Or la thĂ©orie Ă©conomique rĂ©cente, dans le cadre des modĂšles d'Ă©conomie gĂ©ographique, montre que la localisation des mĂ©nages est Ă©troitement liĂ©e Ă celle des entreprises, et que les configurations existant Ă l'Ă©quilibre dĂ©pendent fortement des interrelations entre ces deux catĂ©gories d'agents Ă©conomiques. En d'autres termes, s'il est indispensable de considĂ©rer les choix rĂ©sidentiels des mĂ©nages pour analyser les flux de transport engendrĂ©s par ces derniers, il est tout aussi indispensable de tenir compte des consĂ©quences de ces localisations rĂ©sidentielles sur la localisation des entreprises, et aussi des effets en retour des localisations des entreprises sur la distribution spatiale des mĂ©nages. Cette question fait l'objet du premier axe de notre recherche. En second lieu, les travaux existants nĂ©gligent en gĂ©nĂ©ral le fait que les espaces pĂ©riurbains accueillent des mĂ©nages de catĂ©gories sociales variĂ©es qui ont des comportements diffĂ©rents en termes de dĂ©placement. Or, il semble important de proposer une analyse du dĂ©veloppement pĂ©riurbain intĂ©grant la question du choix rĂ©sidentiel des mĂ©nages en fonction de leur catĂ©gorie sociale, ceci afin de dresser des pistes d'Ă©volution possible des flux de transport engendrĂ©s par les espaces pĂ©riurbains. C'est ce qui est dĂ©veloppĂ© dans le second axe de notre recherche. Enfin, ces analyses portant sur la localisation rĂ©sidentielle des diffĂ©rentes catĂ©gories socio-professionnelles nous amĂšnent aussi Ă analyser la sĂ©grĂ©gation rĂ©sidentielle dans les zones pĂ©riurbaines, en lien avec les dĂ©terminants des choix de localisation rĂ©sidentielle des mĂ©nages. / This research starts from the premise that the existing literature on the sustainability of suburban areas has not provided answers to two specific points. Firstly, the issue of transport is generally considered from the point of view of the transport of persons, in a partial equilibrium framework in which the transport of goods produced and consumed in the city is not taken into account. But the recent economic theory, with the new economic geography models, shows that the location of households is closely linked to the location of firms, and that the existing equilibrium configurations depend strongly on the interrelationships between these two categories of agent. In other words, it is essential to consider the residential choices of households to analyze the traffic flows they generate, but it is also necessary to take into account the consequences of these residential locations on the location of firms and the feedback effects of corporate locations on the spatial distribution of households. This question is the subject of the first axis of our research. Second, existing studies generally neglect the fact that the suburban areas host various social groups of households that have different behaviors in terms of mobility. However, it seems important to provide an analysis of suburban development incorporating the issue of residential choices of households according to their social class, in order to establish avenues for possible evolution of transport flows generated by the suburban areas. This is what is developed in the second focus of our research. Finally, the residential location of the different socio-professional categories is also analyzed in terms of urban segregation, in relation with the determinants of householdsâ choices
Bayesian workflow for disease transmission modeling in Stan
This tutorial shows how to build, fit, and criticize disease transmission
models in Stan, and should be useful to researchers interested in modeling the
SARS-CoV-2 pandemic and other infectious diseases in a Bayesian framework.
Bayesian modeling provides a principled way to quantify uncertainty and
incorporate both data and prior knowledge into the model estimates. Stan is an
expressive probabilistic programming language that abstracts the inference and
allows users to focus on the modeling. As a result, Stan code is readable and
easily extensible, which makes the modeler's work more transparent.
Furthermore, Stan's main inference engine, Hamiltonian Monte Carlo sampling, is
amiable to diagnostics, which means the user can verify whether the obtained
inference is reliable. In this tutorial, we demonstrate how to formulate, fit,
and diagnose a compartmental transmission model in Stan, first with a simple
Susceptible-Infected-Recovered (SIR) model, then with a more elaborate
transmission model used during the SARS-CoV-2 pandemic. We also cover advanced
topics which can further help practitioners fit sophisticated models; notably,
how to use simulations to probe the model and priors, and computational
techniques to scale-up models based on ordinary differential equations
Direct and indirect effects of the COVID-19 pandemic on mortality in Switzerland
The direct and indirect impact of the COVID-19 pandemic on population-level mortality is of concern to public health but challenging to quantify. Using data for 2011â2019, we applied Bayesian models to predict the expected number of deaths in Switzerland and compared them with laboratory-confirmed COVID-19 deaths from February 2020 to April 2022 (study period). We estimated that COVID-19-related mortality was underestimated by a factor of 0.72 (95% credible interval [CrI]: 0.46â0.78). After accounting for COVID-19 deaths, the observed mortality was â4% (95% CrI: â8 to 0) lower than expected. The deficit in mortality was concentrated in age groups 40â59 (â12%, 95%CrI: â19 to â5) and 60â69 (â8%, 95%CrI: â15 to â2). Although COVID-19 control measures may have negative effects, after subtracting COVID-19 deaths, there were fewer deaths in Switzerland during the pandemic than expected, suggesting that any negative effects of control measures were offset by the positive effects. These results have important implications for the ongoing debate about the appropriateness of COVID-19 control measures
Matter-wave laser Interferometric Gravitation Antenna (MIGA): New perspectives for fundamental physics and geosciences
The MIGA project aims at demonstrating precision measurements of gravity with
cold atom sensors in a large scale instrument and at studying the associated
applications in geosciences and fundamental physics. The first stage of the
project (2013-2018) will consist in building a 300-meter long optical cavity to
interrogate atom interferometers and will be based at the low noise underground
laboratory LSBB in Rustrel, France. The second stage of the project (2018-2023)
will be dedicated to science runs and data analyses in order to probe the
spatio-temporal structure of the local gravity field of the LSBB region, a site
of high hydrological interest. MIGA will also assess future potential
applications of atom interferometry to gravitational wave detection in the
frequency band Hz hardly covered by future long baseline optical
interferometers. This paper presents the main objectives of the project, the
status of the construction of the instrument and the motivation for the
applications of MIGA in geosciences. Important results on new atom
interferometry techniques developed at SYRTE in the context of MIGA and paving
the way to precision gravity measurements are also reported.Comment: Proceedings of the 50th Rencontres de Moriond "100 years after GR",
La Thuile (Italy), 21-28 March 2015 - 10 pages, 5 figures, 23 references
version2: added references, corrected typo
S03-05 OA. A less differentiated memory phenotype of Gag-specific CD4+ T-cells during primary HIV infection associates with viral control at 12 months
Nested : Assessing the convergence of Markov chain Monte Carlo when running many short chains
The growing availability of hardware accelerators such as GPUs has generated
interest in Markov chains Monte Carlo (MCMC) workflows which run a large number
of chains in parallel. Each chain still needs to forget its initial state but
the subsequent sampling phase can be almost arbitrarily short. To determine if
the resulting short chains are reliable, we need to assess how close the Markov
chains are to convergence to their stationary distribution. The
statistic is a battle-tested convergence diagnostic but unfortunately can
require long chains to work well. We present a nested design to overcome this
challenge, and introduce tuning parameters to control the reliability, bias,
and variance of convergence diagnostics
EUROFLEETS Cruise Summary Report. Project DIAPICNA: DIAzotrophic PIco-Cyanobacteria in the North Atlantic open ocean: their abundance and importance as a source of new nitrogen at the Azores Front/Current. R/V NRP <i>Dom Carlos</i> I, Cruise No. DIAPICNA-OCE-2011-V01, 25/07/2011 â 03/08/2011, Horta (Portugal)
Pulmonary-Resident Memory Lymphocytes: Pivotal Orchestrators of Local Immunity Against Respiratory Infections
There is increasing evidence that lung-resident memory T and B cells play a critical role in protecting against respiratory reinfection. With a unique transcriptional and phenotypic profile, resident memory lymphocytes are maintained in a quiescent state, constantly surveying the lung for microbial intruders. Upon reactivation with cognate antigen, these cells provide rapid effector function to enhance immunity and prevent infection. Immunization strategies designed to induce their formation, alongside novel techniques enabling their detection, have the potential to accelerate and transform vaccine development. Despite most data originating from murine studies, this review will discuss recent insights into the generation, maintenance and characterisation of pulmonary resident memory lymphocytes in the context of respiratory infection and vaccination using recent findings from human and non-human primate studies
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