Full dimension Rb2He ground triplet potential energy surface and quantum scattering calculations

International audienceWe have developed a three-dimensional potential energy surface for the lowest triplet state of the Rb2He complex. A global analytic fit is provided as in the supplementary material [see supplementary material at http://dx.doi.org/10.1063/1.4709433E-JCPSA6-136-034218 for the corresponding Fortran code]. This surface is used to perform quantum scattering calculations of 4He and 3He colliding with 87Rb2 in the partial wave J = 0 at low and ultralow energies. For the heavier helium isotope, the computed vibrational relaxation probabilities show a broad and strong shape resonance for a collisional energy of 0.15 K and a narrow Feshbach resonance at about 17 K for all initial Rb2 vibrational states studied. The broad resonance corresponds to an efficient relaxation mechanism that does not occur when 3He is the colliding partner. The Feshbach resonance observed at higher collisional energy is robust with respect to the isotopic substitution. However, its effect on the vibrational relaxation mechanism is faint for both isotopes

Communication, Localization and Synchronization of Spacecraft for Swarm Missions

Swarm missions are based on the use of several spacecraft working together to pursue a specific task for a specific mission. To allow these elements to work together, it is necessary for them to be able to communicate with each other and to synchronize themselves within the swarm. Moreover, the mission may likely require knowing the relative or absolute positions of the spacecraft in the swarm. In order to collect simultaneous measurements allowing computing localization and synchronization in the swarm, a full duplex CDMA communication method is studied by CNES. An Inter Satellite Link (ISL) transmitter prototype is currently under development and first performance evaluation is conducted. CNES is also working on measurement signal processing. Based on signal exchange between satellites, one can estimate jointly the distance and clock offset between a pair of satellites. In parallel, CNES is developing a swarm simulator implying both dynamics and functional behavior of each spacecraft in the swarm. First, this simulator will be software only but its architecture will allow integration of hardware equipment in a future version. This simulator will be used for the validation of the services provided by the link at a system level

LiHe spectra from brown dwarfs to helium clusters

International audienceThe detection of Li I lines is the most decisive spectral indicator of substellarity for young brown dwarfs with masses below about 0.06 solar mass. Due to the weakness of the Li resonance lines, it is important to be able to model precisely both their core widths and their wing profiles. This allows an adequate prediction of the mass at which Li lines reappear in the spectra of brown dwarfs for a given age, or reversely an accurate determination of the age of a cluster. We report improved line profiles and the dependence of line width on temperature suitable for modeling substellar atmospheres that were determined from new LiHe molecular potential energies. Over a limited range of density and temperature, comparison with laboratory measurements was used to validate the potential energies which support the spectral line profile theory

Functional Simulation of the Uses of the Onboard Inter-Satellite Network in a Swarm

There are several network simulators (some on the shelves) that are very useful and helpful for network engineering. Nevertheless, none is efficient enough for simulating an onboard network spread among spacecrafts that are moving in space according to Kepler laws. Therefore, we tried to fill this gap by building our own tool based on the CNES expertise in space simulator benches. Our bench simulates the environment and the dynamics of each spacecraft, provides a model of the physical layer of the network layer (i.e. Radio Frequency transmission between moving vehicles) and offers an interface to run actual Flight Software. Embedding flight software allows us to perform functional demonstration of the network use at system level. As a first step, in order to characterize the network, we have implemented a routing policy based on the flooding principle

Biogenic porous silica and silicon sourced from Mexican Giant Horsetail (Equisetum myriochaetum) and their application as supports for enzyme immobilization

Porous silica-based materials are attractive for biomedical applications due to their biocompatibility and biodegradable character. In addition, inorganic supports such as porous silicon are being developed due to integrated circuit chip compatibility and tunable properties leading to a wide range of multidisciplinary applications. In this contribution, biosilica extracted from a rarely studied plant material (Equisetum Myriochaetum), its conversion to silicon and the potential for both materials to be used as supports for enzyme immobilization are investigated. E. myriochaetum was subject to conventional acid digestion to extract biogenic silica with a % yield remarkably higher (up to 3 times) than for other Equisetum sp. (i.e. E. Arvense). The surface area of the isolated silica was ∼400 m2/g, suitable for biotechnological applications. Biogenic silicon was obtained by magnesiothermic reduction. The materials were characterized by SEM-EDX, XRD, FT-IR, ICP-OES, TGA and BET analysis and did not contain significant levels of class 1 heavy elements (such as Pb, Cd, Hg and As). Two commercial peroxidases, horseradish peroxidase (HRP) and Coprinus cinereus peroxidase (CiP) were immobilized onto the biogenic materials using three different functionalization routes: (A) carbodiimide, (B) amine + glutaraldehyde and (C) amine + carbodiimide. Although both biogenic silica and porous silicon could be used as supports differences in behaviour were observed for the two enzymes. For HRP, loading onto biogenic silica via the glutaraldehyde immobilization technique (route B) was most effective. The loading of CiP showed a much higher peroxidase activity onto porous silicon than silica functionalized by the carbodiimide method (route A). From the properties of the extracted materials obtained from Equisetum Myriochaetum and the immobilization results observed, these materials appear to be promising for industrial and biomedical applications

Overview of the current use of levosimendan in France: a prospective observational cohort study

Abstract Background Following the results of randomized controlled trials on levosimendan, French health authorities requested an update of the current use and side-effects of this medication on a national scale. Method The France-LEVO registry was a prospective observational cohort study reflecting the indications, dosing regimens, and side-effects of levosimendan, as well as patient outcomes over a year. Results The patients included ( n = 602) represented 29.6% of the national yearly use of levosimendan in France. They were treated for cardiogenic shock ( n = 250, 41.5%), decompensated heart failure ( n = 127, 21.1%), cardiac surgery-related low cardiac output prophylaxis and/or treatment ( n = 86, 14.3%), and weaning from veno-arterial extracorporeal membrane oxygenation ( n = 82, 13.6%). They received 0.18 ± 0.07 µg/kg/min levosimendan over 26 ± 8 h. An initial bolus was administered in 45 patients (7.5%), 103 (17.1%) received repeated infusions, and 461 (76.6%) received inotropes and or vasoactive agents concomitantly. Hypotension was reported in 218 patients (36.2%), atrial fibrillation in 85 (14.1%), and serious adverse events in 17 (2.8%). 136 patients (22.6%) died in hospital, and 26 (4.3%) during the 90-day follow-up. Conclusions We observed that levosimendan was used in accordance with recent recommendations by French physicians. Hypotension and atrial fibrillation remained the most frequent side-effects, while serious adverse event potentially attributable to levosimendan were infrequent. The results suggest that this medication was safe and potentially associated with some benefit in the population studied

Etude théorique de collisions inélastiques intervenant dans les domaines de la chimie froide et de l’astrochimie : applications au refroidissement et au piégeage moléculaire

Cette thèse, motivée par le développement récent des techniques d’obtention de molécules froides, présente une étude théorique assez complète du système collisionnel ionique 3,4He + N2+. La relaxation rotationnelle de l’ion moléculaire a été décrite dans les régimes froid et ultrafroid, pour lesquels l’interaction spin-rotation du radical paramagnétique joue un rôle crucial. L’apparition de nouvelles résonances spécifiques de cette interaction a été analysée. Un autre phénomène directement lié à cette interaction, celui de la réorientation du moment magnétique associé au spin électronique du diatome induite par collision avec l’hélium, a été étudié d’abord en l’absence puis en présence d’un champ magnétique externe. Les mêmes méthodes de dynamique quantique inélastique ont été utilisées pour l’étude de la collision H2 + HF d’intérêt astrochimique.Abstrac

Etude théorique de collisions inélastiques intervenant dans les domaines de la chimie froide et de l’astrochimie : applications au refroidissement et au piégeage moléculaire

Cette thèse, motivée par le développement récent des techniques d’obtention de molécules froides, présente une étude théorique assez complète du système collisionnel ionique 3,4He + N2+. La relaxation rotationnelle de l’ion moléculaire a été décrite dans les régimes froid et ultrafroid, pour lesquels l’interaction spin-rotation du radical paramagnétique joue un rôle crucial. L’apparition de nouvelles résonances spécifiques de cette interaction a été analysée. Un autre phénomène directement lié à cette interaction, celui de la réorientation du moment magnétique associé au spin électronique du diatome induite par collision avec l’hélium, a été étudié d’abord en l’absence puis en présence d’un champ magnétique externe. Les mêmes méthodes de dynamique quantique inélastique ont été utilisées pour l’étude de la collision H2 + HF d’intérêt astrochimique.Abstrac

Etude théorique de collisions inélastiques intervenant dans les domaines de la chimie froide et de l’astrochimie : applications au refroidissement et au piégeage moléculaire

Cette thèse, motivée par le développement récent des techniques d’obtention de molécules froides, présente une étude théorique assez complète du système collisionnel ionique 3,4He + N2+. La relaxation rotationnelle de l’ion moléculaire a été décrite dans les régimes froid et ultrafroid, pour lesquels l’interaction spin-rotation du radical paramagnétique joue un rôle crucial. L’apparition de nouvelles résonances spécifiques de cette interaction a été analysée. Un autre phénomène directement lié à cette interaction, celui de la réorientation du moment magnétique associé au spin électronique du diatome induite par collision avec l’hélium, a été étudié d’abord en l’absence puis en présence d’un champ magnétique externe. Les mêmes méthodes de dynamique quantique inélastique ont été utilisées pour l’étude de la collision H2 + HF d’intérêt astrochimique.Abstrac