446 research outputs found
Superconducting quantum node for entanglement and storage of microwave radiation
Superconducting circuits and microwave signals are good candidates to realize
quantum networks, which are the backbone of quantum computers. We have realized
a quantum node based on a 3D microwave superconducting cavity parametrically
coupled to a transmission line by a Josephson ring modulator. We first
demonstrate the time-controlled capture, storage and retrieval of an optimally
shaped propagating microwave field, with an efficiency as high as 80%. We then
demonstrate a second essential ability, which is the timed-controlled
generation of an entangled state distributed between the node and a microwave
channel.Comment: 6 pages, 4 figures. Supplementary information can be downloaded as
the ancillary file her
Identification of the hASCT2-binding domain of the Env ERVWE1/syncytin-1 fusogenic glycoprotein
The cellular HERV-W envelope/syncytin-1 protein, encoded by the envelope gene of the ERVWE1 proviral locus is a fusogenic glycoprotein probably involved in the formation of the placental syncytiotrophoblast layer. Syncytin-1-induced in vitro cell-cell fusion is dependent on the interaction with hASCT2. As no receptor binding domain has been clearly defined in the SU of neither the HERV-W Env nor the retroviruses of the same interference group, we designed an in vitro binding assay to evaluate the interaction of the HERV-W envelope with the hASCT2 receptor. Using truncated HERV-W SU subunits, a region consisting of the N-terminal 124 amino acids of the mature SU glycoprotein was determined as the minimal receptor-binding domain. This domain contains several sub-domains which are poorly conserved among retroviruses of this interference group but a region of 18 residus containing the SDGGGX(2)DX(2)R conserved motif was proved to be essential for syncytin-1-hASCT2 interaction
Multilevel Modeling Paradigm in Profile Definition
Building a UML profile entails defining concepts required to cover a specific domain, and then, using stereotypes to map domain concepts onto UML metaclasses. Capture of domain concepts with an object-oriented language (like UML) may be inappropriate, and may impede the mapping, where more than two modeling levels are required. Use of only classes and objects may introduce accidental complexity into the domain model if other modeling levels (e.g. metatype level) are necessary. In such situations, a multilevel paradigm with deep characterization and deep instantiation is recommended to reduce complexity. However, this paradigm deserves to be further explored, and its value for definition of UML profiles assessed. We therefore propose a solution to put in practice the multi-level paradigm within a standard UML 2.x tool. Our solution involves a semi-automatic process that transforms a model annotated with multi-level characteristics into a profile-based implementation. Such automation lessens the gap between domain model and implementation and ensures consistency. As an example, we have taken an excerpt from the MARTE time profile. We then describe the new design opportunities inherent in our process and show how this process facilitates both domain specification and profile definition
Multiplex degenerate PCR coupled with an oligo sorbent array for human endogenous retrovirus expression profiling
Human endogenous retroviruses (HERVs) can be divided into distinct families of tens to thousands of paralogous loci. The expression of HERV elements has been detected in all tissues tested to date, particularly germ cells, embryonic tissues and neoplastic tissues. Hence, the study of HERV expression could represent added value in cancer diagnosis. We developed a quantitative assay combining a multiplex degenerate PCR (MD-PCR) amplification, based on the relative conservation of the pol genes, and a colorimetric Oligo Sorbent Array (OLISA(®)). Nine HERV families were selected and amplification primers and capture probes were designed for each family. The features required to achieve efficient amplification of most of the elements of each HERV family and balanced co-amplification of all HERV families were analyzed. We found that MD-PCR reliability, i.e. equivalence of amplification and dose-effect relationship, relied on the adjustment of three critical parameters: the primer degeneracy, the relative concentration of each primer and the total amount of primers in the amplification mixture. The analysis of tumoral versus normal tissues suggests that this assay could prove useful in tumor phenotyping
Experimental Test of the Numerical Renormalization Group Theory for Inelastic Scattering from Magnetic Impurities
We present measurements of the phase coherence time \tauphi in quasi
one-dimensional Au/Fe Kondo wires and compare the temperature dependence of
\tauphi with a recent theory of inelastic scattering from magnetic impurities
(Phys. Rev. Lett. 93, 107204 (2004)). A very good agreement is obtained for
temperatures down to 0.2 . Below the Kondo temperature , the inverse
of the phase coherence time varies linearly with temperature over almost one
decade in temperature.Comment: 5 pages, 3 figure
Few layers graphene on 6H-SiC(000-1): an STM study
We have analyzed by Scanning Tunnelling Microscopy (STM) thin films made of
few (3-5) graphene layers grown on the C terminated face of 6H-SiC in order to
identify the nature of the azimuthal disorder reported in this material. We
observe superstructures which are interpreted as Moir\'e patterns due to a
misorientation angle between consecutive layers. The presence of stacking
faults is expected to lead to electronic properties reminiscent of single layer
graphene even for multilayer samples. Our results indicate that this apparent
electronic decoupling of the layers can show up in STM data.Comment: 20 page
Quelles perspectives pour les gommiers en zone de savanes d'Afrique centrale ?
International audienceLa production de gomme arabique est déjà une filière importante pour le Tchad et pourrait se développer au Nord Cameroun. Les espèces productrices de gomme arabique, Acacia senegal et Acacia seyal, sont également importantes pour les populations rurales du fait de leur production de fourrage et de leurs vertus fertilisantes (principalement A. senegal), mais pourraient participer de façon plus importante au développement économique de ces pays au transfert de revenus vers ces populations parmi les plus pauvres. La multifonctionalité des espèces gommières et des espaces qui les portent, et la diversité et la pluralité des acteurs concernés doivent être pris en compte par les bailleurs de fonds du développement dans la conception des projets de développement. Des recherches d'accompagnement doivent également être promues pour permettre aux projets de développement de tirer profit de cette multifonctionnalité des gommiers selon des principes socialement et économiquement viables, mais également écologiquement durables: recherches sur l'intégration des gommiers dans des systèmes agro-sylvo-pastoraux stabilisés; recherches sur la mise en place d'une filière organisée allant du petit paysan à l'exportateur. (Résumé d'auteur
Natural history of the ERVWE1 endogenous retroviral locus
BACKGROUND: The human HERV-W multicopy family includes a unique proviral locus, termed ERVWE1, whose full-length envelope ORF was preserved through evolution by the action of a selective pressure. The encoded Env protein (Syncytin) is involved in hominoid placental physiology. RESULTS: In order to infer the natural history of this domestication process, a comparative genomic analysis of the human 7q21.2 syntenic regions in eutherians was performed. In primates, this region was progressively colonized by LTR-elements, leading to two different evolutionary pathways in Cercopithecidae and Hominidae, a genetic drift versus a domestication, respectively. CONCLUSION: The preservation in Hominoids of a genomic structure consisting in the juxtaposition of a retrotransposon-derived MaLR LTR and the ERVWE1 provirus suggests a functional link between both elements
Un profil UML pour la modélisation multiniveau
Publié à TSI -- 29/2010. Ingénierie dirigée par les modèles - pp. 391--419 http://tsi.revuesonline.comBuilding a UML profile is tedious and error-prone. There is no precise methodology to guide the process. Best practices recommend gathering concepts in a technology-independent domain view before implementation. Still, the adequacy of the implementation should be verified. This paper proposes to transform automatically a domain model into a profile-based implementation. To reduce accidental complexity in the domain model and fully benefit from advanced profiling features in the generated profile, our process relies on the multilevel paradigm. The value of this paradigm for the definition of UML profiles is assessed and applied to a subset of the MARTE time model
Electronic structure of epitaxial graphene layers on SiC: effect of the substrate
Recent transport measurements on thin graphite films grown on SiC show large
coherence lengths and anomalous integer quantum Hall effects expected for
isolated graphene sheets. This is the case eventhough the layer-substrate
epitaxy of these films implies a strong interface bond that should induce
perturbations in the graphene electronic structure. Our DFT calculations
confirm this strong substrate-graphite bond in the first adsorbed carbon layer
that prevents any graphitic electronic properties for this layer. However, the
graphitic nature of the film is recovered by the second and third absorbed
layers. This effect is seen in both the (0001)and 4H SiC
surfaces. We also present evidence of a charge transfer that depends on the
interface geometry. It causes the graphene to be doped and gives rise to a gap
opening at the Dirac point after 3 carbon layers are deposited in agreement
with recent ARPES experiments (T.Ohta et al, Science {\bf 313} (2006) 951)
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