857 research outputs found
Configurable unitary transformations and linear logic gates using quantum memories
We show that a set of optical memories can act as a configurable linear
optical network operating on frequency-multiplexed optical states. Our protocol
is applicable to any quantum memories that employ off-resonant Raman
transitions to store optical information in atomic spins. In addition to the
configurability, the protocol also offers favourable scaling with an increasing
number of modes where N memories can be configured to implement an arbitrary
N-mode unitary operations during storage and readout. We demonstrate the
versatility of this protocol by showing an example where cascaded memories are
used to implement a conditional CZ gate.Comment: 5 pages, 2 figure
Spatial mode storage in a gradient echo memory
Three-level atomic gradient echo memory (lambda-GEM) is a proposed candidate
for efficient quantum storage and for linear optical quantum computation with
time-bin multiplexing. In this paper we investigate the spatial multimode
properties of a lambda-GEM system. Using a high-speed triggered CCD, we
demonstrate the storage of complex spatial modes and images. We also present an
in-principle demonstration of spatial multiplexing by showing selective recall
of spatial elements of a stored spin wave. Using our measurements, we consider
the effect of diffusion within the atomic vapour and investigate its role in
spatial decoherence. Our measurements allow us to quantify the spatial
distortion due to both diffusion and inhomogeneous control field scattering and
compare these to theoretical models.Comment: 11 pages, 9 figure
Dihydroxyacetone conversion into lactic acid in an aqueous medium in the presence of metal salts: influence of the ionic thermodynamic equilibrium on the reaction performance
International audienceThe catalytic conversion of dihydroxyacetone (DHA) to lactic acid (LA) via pyruvaldehyde (PA) in aqueous media was studied using different homogeneous metal salts. A kinetic model was developed and the parameters corresponding to each reaction steps were estimated. Agreement between experiments and simulated results was excellent and the performance of the different catalysts was consistent with previous studies described in the literature. Aluminium salts, which show the best performance, were tested in a whole range of concentrations and at different pH, in order to identify the catalytically active ionic species. It was confirmed that the DHA to pyruvaldehyde (PA) dehydration step is catalyzed by both Brønsted and Lewis acids whereas the consecutive reaction of PA to LA is solely catalyzed by Lewis acids. Moreover, comparing thermodynamic analysis of the reaction media and kinetic parameters demonstrated that cationic hydroxyl-aluminium complexes [Al(OH)h] (3-h)+ formed in situ by the hydrolysis of the aluminium aqua complexes like [Al(OH2)6] 3+ are the most active Lewis acids
Fast Optimal Transport Averaging of Neuroimaging Data
Knowing how the Human brain is anatomically and functionally organized at the
level of a group of healthy individuals or patients is the primary goal of
neuroimaging research. Yet computing an average of brain imaging data defined
over a voxel grid or a triangulation remains a challenge. Data are large, the
geometry of the brain is complex and the between subjects variability leads to
spatially or temporally non-overlapping effects of interest. To address the
problem of variability, data are commonly smoothed before group linear
averaging. In this work we build on ideas originally introduced by Kantorovich
to propose a new algorithm that can average efficiently non-normalized data
defined over arbitrary discrete domains using transportation metrics. We show
how Kantorovich means can be linked to Wasserstein barycenters in order to take
advantage of an entropic smoothing approach. It leads to a smooth convex
optimization problem and an algorithm with strong convergence guarantees. We
illustrate the versatility of this tool and its empirical behavior on
functional neuroimaging data, functional MRI and magnetoencephalography (MEG)
source estimates, defined on voxel grids and triangulations of the folded
cortical surface.Comment: Information Processing in Medical Imaging (IPMI), Jun 2015, Isle of
Skye, United Kingdom. Springer, 201
Variations à court terme des compartiments planctoniques d'un lac humique du Bouclier canadien
Les variations spatio-temporelles à court terme des compartiments planctoniques ont été étudiées simultanément du 30 juillet au 5 août 1986 dans un lac humique du Bouclier canadien. L'abondance du bactérioplancton fluctue de 1,4 à 1,7.106 cell. ml.-1 (coloration DAPI) ou de 2,7 à 7,7.106 cell. ml-1; (coloration Acridine Orange). La production du bactérioplancton estimée par incorporation de 3H méthyl thimidine, varie de 4 à 24.106 cell. l-1 h-1. Les valeurs d'activité hétérotrophe potentielle bactérienne estimée par assimilation de 14C glucose, s'échelonnent de 0,007 à 0,065 µg C.l-1. h-1. La biomasse pigmentaire (chlore. a et pheopigments) varie de 6,8 à 21,7 mg.m-3 . La production primaire est très faible (max. : 10 mg C. m-3 .h-1; 20 mg C.m-2 .h-1 ) et décroît très rapidement avec la profondeur (25 % à 82 % dans le premier mètre). Le microzooplancton (Rotifères, Bosmina, nauplies) représente plus de 90 % du peuplement zooplanctonique et les taux de broutage global du macrozooplancton sont faibles (25 % j-1). Les compartiments hétérotrophes prédominent dans le métabolisme du lac par rapport au compartiment autotrophe. Les patrons de variation spatiale reflètent la stratification verticale des compartiments et des processus autotrophes et hétérotrophes. Les maxima de photosynthèse, d'ATP et de production bactérienne se situent dans les eaux épilimnétiques tandis que les maxima d'abondance du bactérioptancton et des pigments se rencontrent dans l'hypolimnion. Le zooplancton est plus dense et broute d'avantage dans la strate 1-3 m. Ces variations spatiales semblent influencer l'activité hétérotrophe potentielle du bactérioptancton. Nos résultats montrent aussi des variations temporelles à court terme de la production primaire, de l'assimilation hétérotrophe et du broutage du macrozooplancton. Cette étude préliminaire met en lumière la nécessité de tenir compte des variations à court terme lors des études des relations trophodynamiques dans les écosystèmes planctoniques.Short term spatial and temporal variations in planktonic compartments were studied simultaneously, from July 30th to August 5th, 1986, in a humic lake on the Canadian Shield. Abundance of bacterioplankton ranged from 1,4 to 1,7 106 cell. ml-1 (DAP1) or from 2,7 to 7,7 106 cell. ml-1 (Acridine Orange). Bacterial production, as measured by incorporation of 3H methyl-thimidine, was estimated at 4-24 106 cells. l-1. h-1 and potential heterotrophic bacterial activity ranged from 0,007 to 0,065 µg C.l-1. h-1, as estimated by 14C glucose incorporation. Pigments biomass (chloro. a and phaeopigments) varied from 6,8 to 21,7 mg m-3. Primary production was low (max. : 10 mg C.m-3. h-1; 20 mg C.m-2. h-1) and decreased rapidly with depth (25-82 % in 1 m depth). Microzooplankton (rotifera, Bosmina, nauplii) accounted for more than 90 % of total numbers and macrozooplankton global grazing rates were low (25 % d-1). The heterotrophic compartments play a greater rate in the lake metabolism than the autotrophic compartment. Spatial variations reflect the stratification of the heterotrophic and autotrophic organisms and processes with depth. Maximum levels in primary production, ATP and bacterial production occur in epilimnetic waters, while maxima in bacterial numbers and algal pigments occur in the hypolimnion. Zooplancton density and macrozooplankton grazing rates were higher in the 1-3 m strata. These spatial patterns seem to influence the vertical profiles of the bacterial potential heterotrophic activity. Our results also show short term temporal variations in primary production, potential heterotrophic activity of bacterioplankton and macrozooplankton grazing rates. This preliminary study stresses the importance of short term variations in the assessment of the trophodynamics of the planktonic food wed
Exposure to Household Air Pollution from Biomass-Burning Cookstoves and HbA1c and Diabetic Status Among Honduran Women
Household air pollution from biomass cookstoves is estimated to be responsible for more than two and a half million premature deaths annually, primarily in low and middle‐income countries where cardiometabolic disorders, such as Type II Diabetes, are increasing. Growing evidence supports a link between ambient air pollution and diabetes, but evidence for household air pollution is limited. This cross‐sectional study of 142 women (72 with traditional stoves and 70 with cleaner‐burning Justa stoves) in rural Honduras evaluated the association of exposure to household air pollution (stove type, 24‐hour average kitchen and personal fine particulate matter [PM2.5] mass and black carbon) with glycated hemoglobin (HbA1c) levels and diabetic status based on HbA1c levels. The prevalence ratio (PR) per interquartile range increase in pollution concentration indicated higher prevalence of prediabetes/diabetes (vs normal HbA1c) for all pollutant measures (eg, PR per 84 μg/m3 increase in personal PM2.5, 1.49; 95% confidence interval [CI], 1.11‐2.01). Results for HbA1c as a continuous variable were generally in the hypothesized direction. These results provide some evidence linking household air pollution with the prevalence of prediabetes/diabetes, and, if confirmed, suggest that the global public health impact of household air pollution may be broader than currently estimated
Prospective evaluation of a new Aspergillus IgG EIA kit for the diagnosis of chronic and allergic pulmonary aspergillosis
International audienc
Declining water resources in response to global warming and changes in atmospheric circulation patterns over southern Mediterranean France
Warming trends are responsible for an observed decrease
of water discharge in southern France (northwestern Mediterranean). Ongoing
climate change and the likely increase of water demand threaten the
availability of water resources over the coming decades. Drought indices
like the Reconnaissance Drought Index (RDI) are increasingly used in climate
characterization studies, but little is known about the relationships
between these indices, water resources, and the overall atmospheric
circulation patterns. In this study, we investigate the relationships
between the RDI, water discharge, and four atmospheric
teleconnection patterns (TPs) for six coastal river basins in southern
France, both for the historical period of the last 60 years and for a
worst-case climatic scenario (RCP8.5) reaching the year 2100. We combine
global and regional climate model (CGM and RCM, respectively) outputs with a
set of observed climatic and hydrological data in order to investigate the
past relationships between the RDI, water discharge, and TPs and to project their
potential evolution in space and time. Results indicate that annual water
discharge can be reduced by −49 % to −88 % by the end of the century under the
extreme climate scenario conditions. Due to unequal links with TPs, the
hydroclimatic evolution is unevenly distributed within the study area.
Indeed a clustering analysis performed with the RDI time series detects two
major climate clusters, separating the eastern and western part of the study
region. The former indicates stronger relationships with the Atlantic TPs
(e.g. the North Atlantic Oscillation (NAO) and the
Scandinavian Oscillation (Scand) patterns), whereas the latter is more closely
related to the Mediterranean TPs (Mediterranean Oscillation (MO) and Western Mediterranean Oscillation (WeMO)). The future climate
simulations predict an antagonistic evolution in both clusters which are
likely driven by decreasing trends of Scand and WeMO. The former provokes a
general tendency of lower P in both clusters during spring, summer, and
autumn, whereas the latter might partly compensate for this evolution by
enhanced precipitation in the eastern cluster during autumn and winter.
However, compared to observations, representation of the Mediterranean TPs
WeMO and MO in the considered climate models is less satisfactory compared
to the Atlantic TPs NAO and Scand, and further improvement of the model
simulations therefore requires better representations of the Mediterranean
TPs.</p
Rapid onset of mafic magmatism facilitated by volcanic edifice collapse
Volcanic edifice collapses generate some of Earth's largest landslides. How such unloading affects the magma storage systems is important for both hazard assessment and for determining long-term controls on volcano growth and decay. Here we present a detailed stratigraphic and petrological analyses of volcanic landslide and eruption deposits offshore Montserrat, in a subduction zone setting, sampled during Integrated Ocean Drilling Program Expedition 340. A large (6–10 km3) collapse of the Soufrière Hills Volcano at ~130 ka was followed by explosive basaltic volcanism and the formation of a new basaltic volcanic center, the South Soufrière Hills, estimated to have initiated <100 years after collapse. This basaltic volcanism was a sharp departure from the andesitic volcanism that characterized Soufrière Hills' activity before the collapse. Mineral-melt thermobarometry demonstrates that the basaltic magma's transit through the crust was rapid and from midcrustal depths. We suggest that this rapid ascent was promoted by unloading following collapse
Obtención de suero anti-Rice stripe necrosis virus por expresión heteróloga de la capside proteica viral
PosterEl entorchamiento del arroz”, causado por el Rice stripe necrosis virus ( es una gran amenaza para el cultivo del arroz en Argentina Hasta la fecha, se desconoce su distribución, cultivares promisoriamente resistentes y no se cuenta con un suero comercial para su detección El objetivo de este trabajo fue la obtención de suero anti RSNV para la detección del virus en un gran número de muestras en simultaneo y de bajo costo.Instituto de Patología VegetalFil: Celli, Marcos Giovani. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Celli, Marcos Giovani. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Bangratz, M. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Pinel Galzi, A. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Brizard, J.P. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Hébrard, E. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); FranciaFil: Brugidou, C. INRAE. CIRAD. Institut de Recherche pour le Développement (IRD); Franci
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