New Results for Light Gravitinos at Hadron Colliders - Tevatron Limits and LHC Perspectives

We derive Feynman rules for the interactions of a single gravitino with (s)quarks and gluons/gluinos from an effective supergravity Lagrangian in non-derivative form and use them to calculate the hadroproduction cross sections and decay widths of single gravitinos. We confirm the results obtained previously with a derivative Lagrangian as well as those obtained with the non-derivative Lagrangian in the high-energy limit and elaborate on the connection between gauge independence and the presence of quartic vertices. We perform extensive numerical studies of branching ratios, total cross sections, and transverse-momentum spectra at the Tevatron and the LHC. From the latest CDF monojet cross section limit, we derive a new and robust exclusion contour in the gravitino-squark/gluino mass plane, implying that gravitinos with masses below $2\cdot10^{-5}$ to $1\cdot10^{-5}$ eV are excluded for squark/gluino-masses below 200 and 500 GeV, respectively. These limits are complementary to the one obtained by the CDF collaboration, $1.1\cdot 10^{-5}$ eV, under the assumption of infinitely heavy squarks and gluinos. For the LHC, we conclude that SUSY scenarios with light gravitinos will lead to a striking monojet signal very quickly after its startup.Comment: 30 pages, 12 figures. Tevatron limit improved and unitarity limit included. Version to be published in Phys. Rev.

Energy Conversion Using New Thermoelectric Generator

During recent years, microelectronics helped to develop complex and varied technologies. It appears that many of these technologies can be applied successfully to realize Seebeck micro generators: photolithography and deposition methods allow to elaborate thin thermoelectric structures at the micro-scale level. Our goal is to scavenge energy by developing a miniature power source for operating electronic components. First Bi and Sb micro-devices on silicon glass substrate have been manufactured with an area of 1cm2 including more than one hundred junctions. Each step of process fabrication has been optimized: photolithography, deposition process, anneals conditions and metallic connections. Different device structures have been realized with different micro-line dimensions. Each devices performance will be reviewed and discussed in function of their design structure.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

3D printing of gas jet nozzles for laser-plasma accelerators

Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular it was reported that appropriate density tailoring can result in improved injection, acceleration and collimation of laser-accelerated electron beams. To achieve such profiles innovative target designs are required. For this purpose we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling (FDM) to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the Salle Jaune terawatt laser at Laboratoire d'Optique Appliqu\'ee

Entangled photons from a strongly coupled quantum dot-cavity system

A quantum dot strongly coupled to a photonic crystal has been recently proposed as a source of entangled photon pairs [R. Johne et al., Phys. Rev. Lett. 100, 240404 (2008)]. The biexction decay via intermediate polariton states can be used to overcome the natural splitting between the exciton states coupled to the horizontally and vertically polarized light modes, so that high degrees of entanglement can be expected. We investigate theoretically the features of realistic dot-cavity systems, including the effect of the different oscillator strength of excitons resonances coupled to the different polarizations of light. We show that in this case, an independent adjustment of the cavity resonances is needed in order to keep a high entanglement degree. We also consider the case when the biexciton-exciton transition is also strongly coupled to a cavity mode. We show that a very fast emission rate can be achieved allowing the repetition rates in the THz range. Such fast emission should however be paid for by a very complex tuning of the many strongly coupled resonances involved and by a loss of quantum efficiency. Altogether a strongly coupled dot-cavity system seems to be very promising as a source of entangled photon pairs.Comment: 7 pages, 5 figure

Yield stress and shear-banding in granular suspensions

We study the emergence of a yield stress in dense suspensions of non-Brownian particles, by combining local velocity and concentration measurements using Magnetic Resonance Imaging with macroscopic rheometric experiments. We show that the competition between gravity and viscous stresses is at the origin of the development of a yield stress in these systems at relatively low volume fractions. Moreover, it is accompanied by a shear banding phenomenon that is the signature of this competition. However, if the system is carefully density matched, no yield stress is encountered until a volume fraction of 62.7 0.3%

Genomic plasticity and rapid host switching can promote the evolution of generalism : a case study in the zoonotic pathogen Campylobacter

This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/I02464X/1, the Medical Research Council (MRC) grants MR/M501608/1 and MR/L015080/1, and the Wellcome Trust grant 088786/C/09/Z. GM was supported by a NISCHR Health Research Fellowship (HF-14–13).Peer reviewedPublisher PD

Francis F. Maury, M.D. (1840 to 1879): an often forgotten pioneer in early American surgery.

Francis F. Maury (Fig. 1) was born on August 9, 1840, in Danville, Kentucky, where he was raised on a farm by his mother and father. His father was an Episcopal clergyman of Huguenot descent, whose forefathers had fled from France to escape religious persecution. After receiving a Bachelor of Arts degree from Center College in the summer of 1860, he entered medical school at the University of Virginia. After one full term, he matriculated to Philadelphia’s Jefferson Medical College and completed his medical education as a private student under the direction of Dr. Samuel D. Gross.1, 2 He obtained his Doctorate of Medicine in March of 1862 at the age of only 21 years. Such were his talents as a medical student that he was appointed resident physician at the Philadelphia Hospital one month before his graduation. Although he spent only one year there, he developed a reputation as a tireless, devoted, and charming surgeon. In April 1863, Maury was assigned to duty at the South Street General Hospital to serve as acting assistant surgeon in the U.S. Army for two years. In October 1863, he was appointed assistant professor to Dr. Gross and six months later became chief of Dr. Gross’ surgical clinic at Jefferson Medical College. In November 1865, at the age of only 25 years, he returned to the Philadelphia Hospital, where he was appointed one of the chief surgeons on the retirement of Dr. Gross from that institution. In April of 1866, Maury founded the Summer Course on Venereal and Cutaneous Diseases in the Jefferson Medical College, where he taught until his death.1 Although Maury did not consider himself a dermatologist, his expertise in this emerging field was widely recognized

Une chaîne d'applications intégrées

Dans leurs phases d'étude, d'installation, de maintenance et de suivi technico-financier des contrats d'appui, les activités du groupe électricité sont largement basées sur l'utilisation d'applications informatiques. Couplées à des bases de données, ces applications CERN étroitement interconnectées, sont développées autour de noyaux informatiques industriels. Toutes les phases d'un projet, tel que le LHC, bénéficient de ces bases de données enrichies par le personnel du CERN et par ses partenaires industriels. Ce document présente le maquettage virtuel des ouvrages du génie-civil et des équipements du CERN. Il traite également de la gestion de ces équipements, de leur câblage, de leur maintenance et du suivi des contrats de sous-traitance