Monodeurated methane in the outer solar system. 2. Its detection on Uranus at 1.6 microns

Deuterium in the atmosphere of Uranus has been studied only via measurements of the exceedingly weak dipole lines of hydrogen-deuteride (HD) seen in the visible region of the spectrum. The other sensitive indicator of deuterium in the outer solar system is monodeuterated methane (CH3D) but the two bands normally used ot study this molecule, NU sub 2 near 2200 1/cm and NU sub 6 near 1161 1/cm, have not been detected in Uranus

Class II ADP-ribosylation factors are required for efficient secretion of Dengue viruses

This article is available open access through the publisher’s website.Identification and characterization of virus-host interactions are very important steps toward a better understanding of the molecular mechanisms responsible for disease progression and pathogenesis. To date, very few cellular factors involved in the life cycle of flaviviruses, which are important human pathogens, have been described. In this study, we demonstrate a crucial role for class II Arf proteins (Arf4 and Arf5) in the dengue flavivirus life cycle. We show that simultaneous depletion of Arf4 and Arf5 blocks recombinant subviral particle secretion for all four dengue serotypes. Immunostaining analysis suggests that class II Arf proteins are required at an early pre-Golgi step for dengue virus secretion. Using a horseradish peroxidase protein fused to a signal peptide, we show that class II Arfs act specifically on dengue virus secretion without altering the secretion of proteins through the constitutive secretory pathway. Co-immunoprecipitation data demonstrate that the dengue prM glycoprotein interacts with class II Arf proteins but not through its C-terminal VXPX motif. Finally, experiments performed with replication-competent dengue and yellow fever viruses demonstrate that the depletion of class II Arfs inhibits virus secretion, thus confirming their implication in the virus life cycle, although data obtained with West Nile virus pointed out the differences in virus-host interactions among flaviviruses. Our findings shed new light on a molecular mechanism used by dengue viruses during the late stages of the life cycle and demonstrate a novel function for class II Arf proteins.Research Fund for Control of Infectious Diseases of Hong Kong and BNP Paribas Corporate and Investment Banking

Answering Conjunctive Queries under Updates

We consider the task of enumerating and counting answers to $k$-ary conjunctive queries against relational databases that may be updated by inserting or deleting tuples. We exhibit a new notion of q-hierarchical conjunctive queries and show that these can be maintained efficiently in the following sense. During a linear time preprocessing phase, we can build a data structure that enables constant delay enumeration of the query results; and when the database is updated, we can update the data structure and restart the enumeration phase within constant time. For the special case of self-join free conjunctive queries we obtain a dichotomy: if a query is not q-hierarchical, then query enumeration with sublinear$^\ast$ delay and sublinear update time (and arbitrary preprocessing time) is impossible. For answering Boolean conjunctive queries and for the more general problem of counting the number of solutions of k-ary queries we obtain complete dichotomies: if the query's homomorphic core is q-hierarchical, then size of the the query result can be computed in linear time and maintained with constant update time. Otherwise, the size of the query result cannot be maintained with sublinear update time. All our lower bounds rely on the OMv-conjecture, a conjecture on the hardness of online matrix-vector multiplication that has recently emerged in the field of fine-grained complexity to characterise the hardness of dynamic problems. The lower bound for the counting problem additionally relies on the orthogonal vectors conjecture, which in turn is implied by the strong exponential time hypothesis. $^\ast)$ By sublinear we mean $O(n^{1-\varepsilon})$ for some $\varepsilon>0$, where $n$ is the size of the active domain of the current database

Surface effects on shape, self-organization and photoluminescence of InAs islands grown on InAlAs/InP(001)

International audienceInAs nanostructures were grown on In 0.52 Al 0.48 As alloy lattice matched on InP001 substrates by molecular beam epitaxy using specific growth parameters in order to improve island self-organization. We show how the change in InAs surface reconstruction via growth temperature from (24) to (21) and/or the use of InAlAs initial buffer surface treatments improve the island shape homogeneity either as quantum wires or as quantum dots. Differences in island shape and in carrier confinement are shown by atomic force microscopy and by photoluminescence measurements, respectively. We point out that such shape amendments induce drastic improvements to island size distribution and discernible changes in photoluminescence properties, in particular concerning polarization

Dynamic saturation of an intersublevel transition in self-organized InAs/In(x)A(1-x)lAs quantum dots

International audienceWe have observed a dynamic saturation of an intersublevel transition in InAs/InxAl1-xAs quantum dots related to the discrete nature of electron states using midinfrared femtosecond spectroscopy. This dynamic saturation is a consequence of the gradual filling of the discrete quantum-dot electron states due to the capture of electrons injected in the barrier. Our interpretation of the differential transmission experiments is confirmed by a comparison with a rate-equation model with the capture and intersublevel relaxation time as fit parameters yielding 10 ps and 1 ps, respectively. We discuss the mechanism responsible for these relaxation times

Optical anisotropy and photoluminescence temperature dependence for self-assembled InAs quantum islands grown on vicinal (001) InP substrates

International audienceIn this paper, we report on a detailed investigation of the effect of misorientated InP(OOl) substrates on the optical properties of InAs quantum islands grown by molecular beam epitaxy in the Stranski-Krastanow regime. Temperature-dependent photoluminescence and polarization of photoluminescence (PPL) are studied. PPL shows a high degree of linear polarization, near 40%, for the sample grown on the substrate with 2°off miscut angle towards [110] direction (2°F) and only 16% for the sample grown on the substrate with 2°off miscut angle towards [010] direction (2°B). This result pointing out the growth ofInAs quantum wires (QWr) on 2°F substrate and of quasi-isotropic InAs quantum dots (QD) on 2°B substrate. The luminescence remains strong at 300 K as much as 36% of that at 8 K, indicating a strong spatial localization of the carriers in the InAs QIs grown on InP(OOl)

The Significance of Energy Storage for Renewable Energy Generation and the Role of Instrumentation and Measurement

International audienceEnergy storage is not a new concept but is currently getting increasing importance in the context of energy transition paradigm. Indeed, it is expected to play a key role as an enabling technology for lowering the carbon footprint of the electric power system. In fact, the growing development of renewable energy resources and their increasing share in the energy mix, are introducing significant challenges to the existing power grid due to the high variability of these sources/loads. In particular, maintaining the generation-consumption balance of the electric power in real time, as well as the overall power system security, when these special energy sources/loads are present at a significant scale is a major concern. With competitive energy storage, it will be possible to introduce more flexibility in the electrical system thus helping it to better manage the overall energy balance with better system response in case of severe contingencies. Energy storage technologies were historically used for managing the load curve while observing generation dynamic constraints. The most well-known storage technology is the pumped hydro storage where the energy is stored in a hydraulic form (water potential energy). With the event of open access and the corresponding unbundling of electric power industry segments, valorizing energy storage options under market conditions has become tricky. The major present barriers for deploying energy storage systems (ESS) are high cost, competitive economic value, efficiency and energy density, together with energy policies. The new energy paradigm has put a new emphasis on energy storage, and many research roadmaps have pointed out the need for overcoming the current barriers. The decision makers' awareness of the importance of energy storage is also on the rise. However, adequate incentives for encouraging massive deployment of ESS and storage technology within the electric power system are still lacking. Currently, most of the effort is dedicated to in situ demonstration projects in striving for smarter grids and support of innovations with the corresponding proofs of concept and feedback experience. Additionally, different grid applications are assessed for both centralized to decentralized uses. Various energy storage applications for frequency regulation, voltage support, investment optimization, or peak shaving are under consideration. In this article, some of the main energy storage technologies will be reviewed according to their main application domains. That will be followed by a focus on battery energy storage. Some key elements of battery management system (BMS) technologies and ESS architecture and characterization will be addressed. Then some aspects of ESS protection will be presented and the key trends and indications of emerging concepts for energy storage will be identified

3-(4-Methoxy­benz­yl)-1-benzothio­phene

In the title compound, C16H14OS, the dihedral angle between the benzothio­phene ring system and the benzene ring is 72.41 (12)°. A weak inter­molecular C—H⋯π inter­action from the benzene ring to the benzothio­phene ring system is observed in the crystal structure

PGC - 1α Overexpression Improves Angiogenic Signaling Potential of Skeletal Muscle - derived Extracellular Vesicles

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Plant and Aphid Partners of Poleroviruses: Role in Virus Transmission by Aphids?

Comité de lecture : trueConférence invitée : falseDate de début de l'événement : 2011-07-11Date de fin de l'évenement : 2011-07-14Date de validation : Tue Aug 13 15:11:30 CEST 2013Diffusion de la pièce jointe : Publique, PubliqueIdentifiant : 200587Langue du titre : engNombre de consultation de la notice : 77Nombre de téléchargements de la pièce jointe : 8Pays de l'événement : BRAPublic visé : ScientifiqueType de communication avec actes : Présentation oraleType d'événement : SymposiumPoleroviruses are phloem limited viruses strictly transmitted by aphids in a circulative and non propagative manner. Virions are acquired by aphids when ingesting sap from infected plants. Virus particles cross the gut epithelium and the accessory salivary gland cells before being released, together with saliva, into the plant during a subsequent feed. This highly specific transcytosis mechanism relies on the presence of virus receptors on the surface of the aphid cells. We developed several approaches to identify virus partners in the plant and in the aphid to analyse their role in virus transmission by the vector. By screening different aphid cDNA libraries using a yeast two hybrid system, only few candidates were able to bind virus structural proteins. Among them, we found two nuclear proteins (GAR1 and ALY) which may not be the true virusreceptors but could be considered as virus-sensors. An Ephrin receptor-like protein was also found to interact with the viral proteins. Involvement of these candidates in virus transport through the aphid needs to be analyzed by developing in the insect RNAi-based techniques. These experiments are in progress. We also looked for plant virus-partners and identified several phloem proteins able to bind purified virions in vitro. We showed that these proteins could stimulate virus transmission by aphids when added together with purified virus to the aphid diet (Bencharki et al. 2010, M.P.M.I., 23: 799). By developing a yeast two hybrid system using a phloem specific cDNA library, we identified five additional proteins able to bind viral proteins. Among them, we found ALY proteins already identified as aphid virus-partners suggesting that orthologous plant and aphid proteins could be implicated in the virus cycle. So far, a direct implication of these proteins in aphid transmission has not been observed and experiments are on going to analyze their functions