Apparatus and method using a holographic optical element for converting a spectral distribution to image points

A holographic optical element transforms a spectral distribution of light to image points. The element comprises areas, each of which acts as a separate lens to image the light incident in its area to an image point. Each area contains the recorded hologram of a point source object. The image points can be made to lie in a line in the same focal plane so as to align with a linear array detector. A version of the element has been developed that has concentric equal areas to match the circular fringe pattern of a Fabry-Perot interferometer. The element has high transmission efficiency, and when coupled with high quantum efficiency solid state detectors, provides an efficient photon-collecting detection system. The element may be used as part of the detection system in a direct detection Doppler lidar system or multiple field of view lidar system

Accelerating Asymptotically Exact MCMC for Computationally Intensive Models via Local Approximations

We construct a new framework for accelerating Markov chain Monte Carlo in posterior sampling problems where standard methods are limited by the computational cost of the likelihood, or of numerical models embedded therein. Our approach introduces local approximations of these models into the Metropolis-Hastings kernel, borrowing ideas from deterministic approximation theory, optimization, and experimental design. Previous efforts at integrating approximate models into inference typically sacrifice either the sampler's exactness or efficiency; our work seeks to address these limitations by exploiting useful convergence characteristics of local approximations. We prove the ergodicity of our approximate Markov chain, showing that it samples asymptotically from the \emph{exact} posterior distribution of interest. We describe variations of the algorithm that employ either local polynomial approximations or local Gaussian process regressors. Our theoretical results reinforce the key observation underlying this paper: when the likelihood has some \emph{local} regularity, the number of model evaluations per MCMC step can be greatly reduced without biasing the Monte Carlo average. Numerical experiments demonstrate multiple order-of-magnitude reductions in the number of forward model evaluations used in representative ODE and PDE inference problems, with both synthetic and real data.Comment: A major update of the theory and example

Inhibitory Activity of Leaves Extracts of Citrullus colocynthis Schrad. on HT29 Human Colon Cancer Cells

Aims: Citrullus colocynthis is a plant endemic in Asia, Africa and in the Mediterranean basin. It is used in folk medicine against infections, inflammations and cardiovascular and immune-related diseases. There are further evidences of the use of Citrullus colocynthis Schrad in the treatment of cancer in traditional practices. The present study aimed to determine the potential antiproliferative effects of different Citrullus colocynthis leaf extracts on human cancer cells. Methodology: Antiproliferative and antioxidant effects on HT-29 human colon cancer cells were detected by MTS assay and a modified protocol of the alkaline Comet assay. In vitro antioxidant activities of different leaf extracts were evaluated through DPPH, \u3b2-carotene/linoleic acid and reducing power assays. Results: The leaf chloroform extract exhibited the higher cell growth inhibitory activity without induction of DNA damage; it showed to be able to significantly decrease DNA damage induced by H2O2 (100 M). This antioxidant activity seems to be comparable to that of vitamin C (1 mM). Ethyl acetate, acetone and methanol leaf extracts showed to be the most effective in reducing the stable free DPPH radical (IC50 =113 g/ml), in transforming the Fe3+ to Fe2+ (IC50 = 134 \ub5g/ml) and in inducing linoleic acid oxidation with an inhibition of 31.9 %. Conclusion: Our results confirm the antiproliferative potential of Citrullus colocynthis Schrad. on human cancer cells

Phthalocyanine-based dumbbell-shaped molecule: synthesis, structure and charge transport studies

International audienceWe describe the synthesis of a fully conjugated donor-acceptor-donor triad (ZnPc-BTD-ZnPc) made of zinc phthalocyanine donor fragments (ZnPc) at both ends of a benzothiadiazole-based central dye (BTD). The molecule exhibits a broad absorption in the whole visible range. The introduction of sterically demanding alkoxy chains to the ZnPc fragments is found to limit the molecular organization to a short-range columnar order and the charge-carrier mobility to moderate values, but provides outstanding solubilities in organic solvents

Experimental Study of an Acoustically Excited Plane Jet at Low Reynolds Numbers

The dynamics of a vertical two-dimensional air jet under acoustic excitations at a low Reynolds number are investigated experimentally. The perturbation is introduced by means of a loudspeaker located in a settling chamber before the nozzle exit. The experiments are operated at Strouhal number St ranging from 0 to 1 and for different pulsation amplitudes. A laser plan is used to visualize the flow and the hot-wire anemometry for more specific measures of the mean and fluctuation velocity. The discussion is focused on the influence of two parameters governing the flow: the Strouhal number St and pulsing amplitude. The main results show that the flow consisting of the vortex propagating downstream a nozzle exit is strongly affected by the excitation. Indeed, the introduction of an external perturbation introduces a more rapid degeneration of the potential core with the appearance of vortices near the nozzle as the pulsation amplitude increases. These vortices are amplified and become larger than the nozzle width which induces the enhancing of the entrainment and mixing effects of the shear layers. Another very important phenomenon is observed: the excitation has led to the formation of a switching from the asymmetric mode (sinuous mode) to the symmetric mode (varicose mode)

Psychosocial health among immigrants in central and southern Europe.

Migration exposes people to a number of risks that threaten their health, including those related to psychosocial health. Self-perceived health is usually the main indicator used to assess psychosocial health. Electronic databases were used to examine the literature on the psychosocial health of immigrants in Europe and of North Africans living in their own countries. Immigrants of various ethnic groups show a similar risk of psychosocial disorders but generally present a higher risk than the local population. This risk is related to gender (being higher in women), poor socio-economic status and acculturation, discrimination, time elapsed since migration and age on arrival in the new country. Although the stressors and situations the different ethnic groups experience in the host country may be shared, the way they deal with them may differ according to cultural factors. There is a need to collect detailed data on psychosocial health among the various immigrant groups in Europe, as well as to monitor this aspect in North African residents who lack access to specific services

Bayesian reconstruction of binary media with unresolved fine-scale spatial structures

We present a Bayesian technique to estimate the fine-scale properties of a binary medium from multiscale observations. The binary medium of interest consists of spatially varying proportions of low and high permeability material with an isotropic structure. Inclusions of one material within the other are far smaller than the domain sizes of interest, and thus are never explicitly resolved. We consider the problem of estimating the spatial distribution of the inclusion proportion, F(x), and a characteristic length-scale of the inclusions, δ, from sparse multiscale measurements. The observations consist of coarse-scale (of the order of the domain size) measurements of the effective permeability of the medium (i.e., static data) and tracer breakthrough times (i.e., dynamic data), which interrogate the fine scale, at a sparsely distributed set of locations. This ill-posed problem is regularized by specifying a Gaussian process model for the unknown field F(x) and expressing it as a superposition of Karhunen–Loève modes. The effect of the fine-scale structures on the coarse-scale effective permeability i.e., upscaling, is performed using a subgrid-model which includes δ as one of its parameters. A statistical inverse problem is posed to infer the weights of the Karhunen–Loève modes and δ, which is then solved using an adaptive Markov Chain Monte Carlo method. The solution yields non-parametric distributions for the objects of interest, thus providing most probable estimates and uncertainty bounds on latent structures at coarse and fine scales. The technique is tested using synthetic data. The individual contributions of the static and dynamic data to the inference are also analyzed.United States. Dept. of Energy. National Nuclear Security Administration (Contract DE-AC04_94AL85000

L’hemorragie grave du peripartum en milieu de reanimation dans un centre universitaire tunisien de niveau 3: épidémiologie et facteurs de risque de mortalité maternelle

L'hémorragie grave du péripartum demeure une des causes principales de mortalité maternelle. L'objectif de notre étude était de décrire le profil épidémiologique des patientes qui ont été prises en charge en milieu de réanimation suite à une hémorragie grave du péripartum et de rechercher d'éventuels facteurs de risque de mortalité. Notre étude est rétrospective descriptive et analytique. Nous avons inclus tous les cas d'hémorragie du péripartum ayant séjourné en unité de réanimation obstétricale du centre de maternité et de néonatologie de Tunis (CMNT) au cours de la période allant de janvier 2010 à Décembre 2013. Nous avons recueilli les paramètres démographiques, obstétricaux, ceux relatifs à la prise en charge chirurgicale et réanimatoire, les scores de gravité SAPS obstétrical et APACHEII, ainsi que la morbi-mortalité. Au total nous avons colligé 322 cas sur quatre ans. La répartition annuelle des patientes ainsi que les caractéristiques démographiques et obstétricales étaient comparables dans leur globalité sur les quatre années. Les pratiques thérapeutiques étaient également comparables. Le taux global de mortalité par hémorragie dans notre unité était à 4,7%, avec un taux annuel de mortalité stable. L'analyse des facteurs de risque de mortalité par hémorragie en milieu de réanimation a montré une association statistiquement significative entre la survenue du décès et les facteurs suivants : recours aux catécholamines, survenue de sepsis, oedème pulmonaire aigu, coagulation intravasculaire disséminée, insuffisance rénale aigue avec recours à l'hémodialyse, SDRA ou TRALI, atteinte neurologique grave, défaillance multiviscérale et arrêt cardiaque récupéré

Higher critical current density achieved in Bi-2223 High-Tc superconductors

AbstractBi2Sr2Ca2Cu3Ox (Bi-2223) were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature Tc and critical current density Jc values were measured using superconducting quantum interference device magnetometer (SQUID) and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T) at 110 K and Jc around 1.2 × 107 A/m2 at 5 K are confirmed for the Bi-2223 compound

Diffeomorphic random sampling using optimal information transport

In this article we explore an algorithm for diffeomorphic random sampling of nonuniform probability distributions on Riemannian manifolds. The algorithm is based on optimal information transport (OIT)---an analogue of optimal mass transport (OMT). Our framework uses the deep geometric connections between the Fisher-Rao metric on the space of probability densities and the right-invariant information metric on the group of diffeomorphisms. The resulting sampling algorithm is a promising alternative to OMT, in particular as our formulation is semi-explicit, free of the nonlinear Monge--Ampere equation. Compared to Markov Chain Monte Carlo methods, we expect our algorithm to stand up well when a large number of samples from a low dimensional nonuniform distribution is needed.Comment: 8 pages, 3 figure