Next Generation High Throughput Satellite System

This paper aims at presenting an overview of the state-of-the-art in High Throughput Satellite (HTS) systems for Fixed Satellite Services (FSS) and High Density-FSS. Promising techniques and innovative strategies that can enhance system performance are reviewed and analyzed aiming to show what to expect for next generation ultra-high capacity satellite systems. Potential air interface evolutions, efficient frequency plans,feeder link dimensioning strategies and interference cancellation techniques are presented to show how Terabit/s satellite myth may turn into reality real soon

Les moteurs de l'intensification écologique de la production laitière à l'ouest du Burkina Faso

Dans les zones de savane d'Afrique de l'Ouest, et notamment à l'ouest du Burkina Faso, l'augmentation de la demande en lait et l'installation de mini-laiteries incitent les producteurs à développer la production de lait locale. Quels sont les moteurs de l'augmentation de la production laitière ? Cette augmentation correspond-elle à une intensification écologique de la production ? Pour apporter des réponses à ces questions avons conduit une enquête chez une trentaine de producteurs de lait des environ de Bobo-Dioulasso, Banfora et Koumbia. Nous avons identifié trois classes de producteurs de lait en fonction du rendement moyen de lait par vache et par jour : 1) Les spécialisés lait (15 vaches traites, 7 zébus et 8 croisées ; 4,6 l/UBT/j ; ration composée de 1,3 kg/UBT/j de pâturage, 4,0 kg/UBT/j de fourrages, 6,1 kg/UBT/j d'aliments ; 1443 kg/an de fourrages stockés ; 492 kg/UBT/an de fumure organique produite) 2) ; les agropasteurs à rendement lait moyen (10 vaches traites, 8 zébus et 2 croisées ; 1,3 l/UBT/an ; ration composée de 4,5 kg/UBT/j de pâturage, 2,6 kg/UBT/j de fourrages, 0,4 kg/UBT/j d'aliments ; 939 kg/an de fourrages stockés ; 322 kg/UBT/an de fumure organique produite) ; 3) les agropasteurs à bas rendement laitier (8 vaches traites, 7 zébus et 1 croisée, 0,9 l/UBT/an ; ration composée de 4,6 kg/UBT/j de pâturage, 1,7 kg/UBT/j de fourrages, 0,2 kg/UBT/j d'aliments ; 636 kg/an de fourrages stockés ; 309 kg/UBT/an de fumure organique produite). L'étude montre que le renforcement de l'association agriculture-élevage combinée à une amélioration génétique appropriée, et à l'affiliation à une laiterie, sont actuellement les principaux moteurs de l'intensification écologique de la production laitière. Elle permet aussi de relever des points de vigilance concernant l'amélioration des pratiques d'association de l'agriculture et de l'élevage, de sélection génétique et de mise en marché du lait pour que les évolutions en cours se poursuivent bien vers une réelle transition agro-écologique et ne basculent pas vers des schémas d'intensification classique

Nonlocal Entanglement Transformations Achievable by Separable Operations

For manipulations of multipartite quantum systems, it was well known that all local operations assisted by classical communication (LOCC) constitute a proper subset of the class of separable operations. Recently, Gheorghiu and Griffiths found that LOCC and general separable operations are equally powerful for transformations between bipartite pure states. In this letter we extend this comparison to mixed states and show that in general separable operations are strictly stronger than LOCC when transforming a mixed state to a pure entangled state. A remarkable consequence of our finding is the existence of entanglement monotone which may increase under separable operations.Comment: v2 has rephrased Theorem 1 and corrected Kraus operators in Theorem 2. Additional comments are welcome

Linear Precoding performance analysis in a Broadband satellite system with a 2-color dual-polarization reuse scheme

The potential of Joint Multiuser Processing in multi-beam satellite systems is assessed in this paper and proved to be a potential attractive alternative to current systems. The present contribution aims at investigating linear precoding techniques over an accurate multi-beam architecture modeling and system characterization. Power and precoder design problems are approached through well-known linear precoding techniques such as Zero Forcing (ZF) and Regularized-ZF. A dual-polarization 2-color reutilization scheme is considered in combination with precoding techniques. Results show a total throughput improvement of +22% achieved by ZF and +38% considering R-ZF, with respect to a conventional 4-color reuse scheme scenario

Knocking on heaven's door : are novel invaders necessarily facing naive native species on islands ?

The impact of alien predator species on insular native biota has often been attributed to island prey naivete (i.e. lack of, or inefficient, anti-predator behavior). Only rarely, however, has the concept of island prey naivete been tested, and then only a posteriori (i.e. hundreds or thousands of years after alien species introduction). The presence of native or anciently introduced predators or competitors may be crucial for the recognition and development of adaptive behavior toward unknown predators or competitors of the same archetype (i.e. a set of species that occupy a similar ecological niche and show similar morphological and behavioral traits when interacting with other species). Here, we tested whether two squamates endemic to New Caledonia, a skink, Caledoniscincus austrocaledonicus, and a gecko, Bavayia septuiclavis, recognized and responded to the odor of two major invaders introduced into the Pacific islands, but not yet into New Caledonia. We chose one predator, the small Indian mongoose Herpestes javanicus and one competitor, the cane toad Rhinella marina, which belong respectively to the same archetype as the following two species already introduced into New Caledonia in the nineteenth century: the feral cat Felis catus and the golden bell frog Litoria aurea. Our experiment reveals that geckos are naive with respect to the odors of both an unknown predator and an unknown competitor, as well as to the odors of a predator and a competitor they have lived with for centuries. In contrast, skinks seem to have lost some naivete regarding the odor of a predator they have lived with for centuries and seem "predisposed" to avoid the odor of an unknown potential competitor. These results indicate that insular species living in contact with invasive alien species for centuries may be, although not systematically, predisposed toward developing adaptive behavior with respect to species belonging to the same archetype and introduced into their native range

Etude sur l\u27usage des lecteurs des lecteurs d\u27écran en France et en Francophonie

la Fédération des Aveugles de France, en partenariat avec la société Access42, a mené une enquête par questionnaire portant sur l’usage des lecteurs d’écran en France et en Francophonie. Cette étude permet d’identifier les outils les plus utilisés. Elle permet de guider les choix des bibliothèques souhaitant équiper certains postes informatiques de lecteurs d’écran

Intermittent outgassing through a non-Newtonian fluid

10 pages, 11 figuresInternational audienceWe report an experimental study of the intermittent dynamics of a gas flowing through a column of a non-Newtonian fluid. In a given range of the imposed constant flow rate, the system spontaneously alternates between two regimes: bubbles emitted at the bottom either rise independently one from the other or merge to create a winding flue which then connects the bottom air entrance to the free surface. The observations are reminiscent of the spontaneous changes in the degassing regime observed on volcanoes and suggest that, in the nature, such a phenomenon is likely to be governed by the non-Newtonian properties of the magma. We focus on the statistical distribution of the lifespans of the bubbling and flue regimes in the intermittent steady state. The bubbling regime exhibits a characteristic time whereas, interestingly, the flue lifespan displays a decaying power-law distribution. The associated exponent, which is significantly smaller than the value 1.5 often reported experimentally and predicted in some standard intermittency scenarios, depends on the fluid properties and can be interpreted as the ratio of two characteristic times of the system

Depolarization channel for barcelona lidar. Implementation and preliminary measurements

A new depolarization channel has beenimplemented in the BarcelonaTech University(UPC) multi-wavelength lidar system. The opticaland mechanical designs are presented. The specialconfiguration of the total power channel is alsodetailed, with the relevant aspects in measurement inversion. Some preliminary measurements arepresented for Saharan dust intrusion events.Peer ReviewedPostprint (published version