Message handling system concepts and services in a land mobile satellite system

A network architecture containing the capabilities offered by the Message Handling System (MHS) to the PRODAT Land Mobile Satellite System (LMSS) is described taking into account the constraints of a preexisting satellite system which is going to become operational. The mapping between MHS services and PRODAT requirements is also reported and shows that the supplied performance can be significantly enhanced to both fixed and mobile users. The impact of the insertion of additional features on the system structure, especially on the centralized control unit, are also addressed

Tomonaga-Luttinger physics in electronic quantum circuits

In one-dimensional conductors, interactions result in correlated electronic systems. At low energy, a hallmark signature of the so-called Tomonaga-Luttinger liquids (TLL) is the universal conductance curve predicted in presence of an impurity. A seemingly different topic is the quantum laws of electricity, when distinct quantum conductors are assembled in a circuit. In particular, the conductances are suppressed at low energy, a phenomenon called dynamical Coulomb blockade (DCB). Here we investigate the conductance of mesoscopic circuits constituted by a short single-channel quantum conductor in series with a resistance, and demonstrate a proposed link to TLL physics. We reformulate and establish experimentally a recently derived phenomenological expression for the conductance using a wide range of circuits, including carbon nanotube data obtained elsewhere. By confronting both conductance data and phenomenological expression with the universal TLL curve, we demonstrate experimentally the predicted mapping between DCB and the transport across a TLL with an impurity.Comment: 9p,6fig+SI; to be published in nature comm; v2: mapping extended to finite range interactions, added discussion and SI material, added reference

Observation of a New Fluxon Resonant Mechanism in Annular Josephson Tunnel Structures

A novel dynamical state has been observed in the dynamics of a perdurbed sine-Gordon system. This resonant state, has been experimentally observed as a singularity in the dc current voltage characteristic of an annular Josephson tunnel junction, excited in the presence of a magnetic field. With this respect, it can be assimilated to self-resonances known as Fiske steps. Differently from these, however, we demonstrate, on the basis of numerical simulations, that its detailed dynamics involves rotating fluxon pairs, a mechanism associated, so far, to self-resonances known as zero-field steps.Comment: 4 pages, 2 figures, submitted to Physical Review Letter

Unique morphologies of <i>Encheliophis vermiops</i> (Carapidae) with revised diagnosis of the genus

Encheliophis vermiops was first briefly described in 1990 on the basis of three specimens. This study validates this species and provides previously unrecorded useful characters to realise the identification: (1) the forward orientation of the palatine teeth, (2) the enlarged teeth of the third basibranchial, (3) the particularly well-developed pharyngeal apparatus, (4) the unpigmented band along the base of anal fin and (5) the insertion of the primary sonic muscle on the parasphenoid. Moreover, the particular morphology of Encheliophis vermiops forces us to reconsider the diagnosis of the genus

Contribution de la biologie moléculaire à la sélection animale: les marqueurs génétiques

Avec la domestication des animaux de rente, les éleveurs ont cherché d'une part, à accroître les performances de leurs animaux en sélectionnant dans la population mise à leur disposition les sujets les plus performants pour la (les) caractéristique(s) recherchée(s) et d'autre part, à réduire l'impact des zoonoses en sélectionnant les animaux résistants. Toutefois, si cette approche de la sélection a permis inconsciemment de favoriser au sein de la population les génotypes intéressants pour les critères recherchés, il importe de garder en mémoire que la production et la santé animale résultent non seulement du potentiel génétique mais également d'interactions entre l'alimentation, le statut physiologique, les facteurs environnementaux et le savoir-faire de l'éleveur

Self-enrichment in globular clusters. I. An analytic approach

By means of analytical calculations, we explore the self-enrichment scenario for Globular Cluster formation. According to this scenario, an initial burst of star formation occurs inside the core radius of the initial gaseous distribution. The outward-propagating shock wave sweeps up a shell in which gravitational instabilities may arise, leading to the formation of a second, metal-enriched, population of stars. We find a minimum mass of the proto-globular cluster of the order of 10^6 solar masses. We also find that the observed spread in the Magnitude-Metallicity relation can be explained assuming cluster-to-cluster variations of some parameters like the thermalization efficiency, the mixing efficiency and the Initial Mass Function, as well as variations of the external pressure.Comment: 12 pages, 13 figures, accepted for publication in A&

Determining the origin of seafood products on the Belgian market: challenges to traceability and database management

In countries where the majority of the seafood is imported, information about seafood origin is important in particular from a food safety perspective. In the case of Belgium, no database is available describing the origin of commercial seafood products. This investigation to determine the origin revealed three important problems. First, information needed to stem from different non-related databases; second, import countries did not define fishing grounds or product sites; third, seafood may have transited many areas and no information was available on this. Since European traceability regulations have been established for seafood, some limited extra efforts with respect to data collection and management can lead to (inter)national databases making seafood traceability information more practically useful, for example towards public health policy making

Délimitation et identification des espèces végétales en Afrique centrale - apport des approches de génétique des populations et de phylogéographie

La délimitation des espèces végétales ainsi que leur identification sur le terrain est une difficulté récurrente dans les forêts tropicales humides. Bien que le choix des taxons pour nos études phylogéographiques reposait sur des espèces a priori sans problème taxonomique, il est rapidement apparu que nos données pouvaient, dans certains cas, remettre en question la taxonomie adoptée. Des éclaircissements sur la délimitation des espèces seront présentés pour les arbres des genres Carapa, Erythrophleum, Greenwayodendron et Santiria et les lianes du genre Haumania. Dans certains cas les marqueurs génétiques confirment la classification taxonomique et permettent d'identifier a posteriori des espèces difficiles à distinguer sur le terrain (Erythrophleum). D'autres cas suggèrent que la classification taxonomique ne reflète pas des espèces au sens biologique (Santiria, Greenwayodendron). Enfin, des cas d'incongruence entre génomes cytoplasmique et nucléaire mettent en évidence des phénomènes d'introgression et donc une spéciation inachevée. Ainsi, les séquences de gènes chloroplastiques ne sont pas toujours fiables pour délimiter ou identifier les espèces. Enfin, une analyse de barre-codes ADN basée sur le génome chloroplastique chez les espèces d'arbres d'un plot de 50ha à Korup (Cameroun) montre que seulement près de 60% des espèces et 80% des genres peuvent être identifiés par cette approche avec le gène rbcL. (Texte intégral

Two-channel Kondo effect and renormalization flow with macroscopic quantum charge states

Many-body correlations and macroscopic quantum behaviors are fascinating condensed matter problems. A powerful test-bed for the many-body concepts and methods is the Kondo model which entails the coupling of a quantum impurity to a continuum of states. It is central in highly correlated systems and can be explored with tunable nanostructures. Although Kondo physics is usually associated with the hybridization of itinerant electrons with microscopic magnetic moments, theory predicts that it can arise whenever degenerate quantum states are coupled to a continuum. Here we demonstrate the previously elusive `charge' Kondo effect in a hybrid metal-semiconductor implementation of a single-electron transistor, with a quantum pseudospin-1/2 constituted by two degenerate macroscopic charge states of a metallic island. In contrast to other Kondo nanostructures, each conduction channel connecting the island to an electrode constitutes a distinct and fully tunable Kondo channel, thereby providing an unprecedented access to the two-channel Kondo effect and a clear path to multi-channel Kondo physics. Using a weakly coupled probe, we reveal the renormalization flow, as temperature is reduced, of two Kondo channels competing to screen the charge pseudospin. This provides a direct view of how the predicted quantum phase transition develops across the symmetric quantum critical point. Detuning the pseudospin away from degeneracy, we demonstrate, on a fully characterized device, quantitative agreement with the predictions for the finite-temperature crossover from quantum criticality.Comment: Letter (5 pages, 4 figures) and Methods (10 pages, 6 figures