High-Quality Planar high-Tc Josephson Junctions

Reproducible high-Tc Josephson junctions have been made in a rather simple two-step process using ion irradiation. A microbridge (1 to 5 ?m wide) is firstly designed by ion irradiating a c-axis-oriented YBa2Cu3O7-? film through a gold mask such as the non-protected part becomes insulating. A lower Tc part is then defined within the bridge by irradiating with a much lower fluence through a narrow slit (20 nm) opened in a standard electronic photoresist. These planar junctions, whose settings can be finely tuned, exhibit reproducible and nearly ideal Josephson characteristics. This process can be used to produce complex Josephson circuits.Comment: 4 pages, 5 figures, to be published in Applied Physics Letter

Einstein Radii from Binary Lensing Events

We show that the Einstein ring radius and transverse speed of a lens projected on the source plane, $\hat{r}_{\rm e}$ and $\hat{v}$, can be determined from the light curve of a binary-source event, followed by the spectroscopic determination of the orbital elements of the source stars. The determination makes use of the same principle that allows one to measure the Einstein ring radii from finite-source effects. For the case when the orbital period of the source stars is much longer than the Einstein time scale, $P\gg t_{\rm e}$, there exists a single two-fold degeneracy in determining $\hat{r}_{\rm e}$. However, when $P \lesssim t_{\rm e}$ the degeneracy can often be broken by making use of the binary-source system's orbital motion. %Once $\hat{r}_{\rm e}$, and thus $\hat{v}$ are determined, one can %distinguish self-lensing events in the Large Magellanic Cloud %from Galactic halo events. For an identifiable 8\% of all lensing events seen toward the Large Magellanic Cloud (LMC), one can unambiguously determine whether the lenses are Galactic, or whether they lie in the LMC itself. The required observations can be made after the event is over and could be carried out for the $\sim 8$ events seen by Alcock et al.\ and Aubourg et al.. In addition, we propose to include eclipsing binaries as sources for gravitational lensing experiments.Comment: 18 pages, revised version, submitted to Ap

Photometric Solutions for Detached Eclipsing Binaries: selection of ideal distance indicators in the SMC

Detached eclipsing binary stars provide a robust one-step distance determination to nearby galaxies. As a by-product of Galactic microlensing searches, catalogs of thousands of variable stars including eclipsing binaries have been produced by the OGLE, MACHO and EROS collaborations. We present photometric solutions for detached eclipsing binaries in the Small Magellanic Cloud (SMC) discovered by the OGLE collaboration. The solutions were obtained with an automated version of the Wilson-Devinney program. By fitting mock catalogs of eclipsing binaries we find that the normalized stellar radii (particularly their sum) and the surface brightness ratio are accurately described by the fitted parameters and estimated standard errors, despite various systematic uncertainties. In many cases these parameters are well constrained. In addition we find that systems exhibiting complete eclipses can be reliably identified where the fractional standard errors in the radii are small. We present two quantitatively selected sub-samples of eclipsing binaries that will be excellent distance indicators. These can be used both for computation of the distance to the SMC and to probe its structure. One particularly interesting binary has a very well determined solution, exhibits complete eclipses, and is comprised of well detached G-type, class $II$ giants.Comment: 29 pages, 12 figures. To be published in Ap

The Optical Gravitational Lensing Experiment. Short Distance Scale to the LMC

We present {\it UBVI} photometry of the eclipsing binary HV2274 - the system which has been recently used for distance determination to the LMC by Guinan et al. (1998). We determine the interstellar reddening to the star, E(B-V)=0.149+/-0.015 mag, based on observed colors of the star. This value is in excellent agreement with the mean reddening towards HV2274 obtained from photometry of the red clump stars in the surrounding field. The reddening is almost twice as large as determined by Guinan et al. (1998). We discuss the consequences of reddening underestimate. Most likely HV2274 is located much closer with the distance modulus to the star and the LMC: m-M = 18.22+/-0.13 mag supporting the short distance scale to the LMC. Such a distance modulus is in excellent agreement with the recent distance determinations with RR Lyr and red clump stars.Comment: 11 pages, Latex, 2 Figures. Accepted for publication in Astrophysical Journal Letters. New version - trimmed to fit ApJL. Additional determination of the reddening towards HV2274 with OB star

High Tc Josephson nanoJunctions made by ion irradiation : characteristics and reproducibility

Reproducible High Tc Josephson junctions have been made in a rather simple two-step process using ion irradiation. A microbridge 1 to 5 micrometers wide is firstly designed by ion irradiating a c-axis-oriented YBa2Cu3O7 film through a gold mask such as the unprotected part becomes insulating. A lower Tc part is then defined within the bridge by irradiating with a much lower dose through a 20 nm wide narrow slit opened in a standard electronic photoresist. These planar junctions, whose settings can be finely tuned, exhibit reproducible and nearly ideal Josephson characteristics. Non hysteretic Resistively Shunted Junction (RSJ) like behavior is observed, together with sinc Fraunhofer patterns for rectangular junctions. The IcRn product varies with temperature ; it can reach a few mV. The typical resistance ranges from 0.1 to a few ohms, and the critical current density can be as high as 30 kA/cm2. The dispersion in characteristics is very low, in the 5% to 10% range. Such nanojunctions have been used to make microSQUIDs (Superconducting Quantum Interference Device) operating at Liquid Nitrogen (LN2) temperature. They exhibit a very small asymmetry, a good sensitivity and a rather low noise. The process is easily scalable to make rather complex Josephson circuits.Comment: 4 pages, 5 figures, Applied Superconductivity Conference Seattle 200

Plasma membrane-associated receptor like kinases relocalize to plasmodesmata in response to osmotic stress

Plasmodesmata act as key elements in intercellular communication, coordinating processes related to plant growth, development, and responses to environmental stresses. While many of the developmental, biotic, and abiotic signals are primarily perceived at the plasma membrane (PM) by receptor proteins, plasmodesmata also cluster receptor-like activities; whether these two pathways interact is currently unknown. Here we show that specific PM-located Leucine-Rich-Repeat Receptor-Like-Kinases (LRR-RLKs), QSK1 and IMK2, which under optimal growth conditions are absent from plasmodesmata, rapidly relocate and cluster to the pores in response to osmotic stress. This process is remarkably fast, is not a general feature of PM-associated proteins, and is independent of sterol- and sphingolipid- membrane composition. Focusing on QSK1, previously reported to be involved in stress responses, we show that relocalisation in response to mannitol depends on QSK1 phosphorylation. Loss-of-function mutation in QSK1 results in delayed lateral root (LR) development and the mutant is affected in the root response to mannitol stress. Callose-mediated plasmodesmata regulation is known to regulate LR development. We found that callose levels are reduced in the qsk1 mutant background with a root phenotype resembling ectopic expression of PdBG1, an enzyme that degrades callose at the pores. Both the LR and callose phenotypes can be complemented by expression of wild-type and phosphomimic QSK1 variants, but not by phosphodead QSK1 mutant which fails to relocalise at plasmodesmata. Together the data indicate that re-organisation of RLKs to plasmodesmata is important for the regulation of callose and LR development as part of the plant response to osmotic stress

Mini-bandelette sous-urétrale versus bandelette transobturatrice : efficacité et morbidité

Objectif Comparer l’efficacité d’une mini-bandelette ALTIS® et d’une bandelette sous-urétrale (BSU) classique transobturatrice TVT-ABBREVO® pour le traitement de l’incontinence urinaire d’effort féminine. Méthodes Une étude rétrospective monocentrique incluait toutes les patientes opérées par BSU transobturatrice (TVT-ABBREVO®) ou mini-bandelette (ALTIS®) en 2015, au centre hospitalier universitaire d’Angers. Le taux de succès était défini par l’amélioration de la qualité de vie définie par un score PGI-I (Patient Global Impression of Improvement) compris entre 1 et 3, l’absence de fuite urinaire lors d’un test à la toux à l’examen clinique, et l’absence de fuite urinaire à l’effort rapportée sur le questionnaire USP (Urinary Symptom Profile). La morbidité liée aux bandelettes ainsi que les données peropératoires étaient également répertoriées. Résultats Quatre-vingt-douze patientes étaient incluses (39 dans le groupe ALTIS et 53 dans le groupe ABBREVO). Le suivi moyen était de 13,55 mois. Le taux de succès n’était pas significativement différent dans le groupe ALTIS que ce soit pour le test à la toux négatif (89,7 % vs 94,3 % dans le groupe ABBREVO, p = 0,45), pour l’absence de fuite urinaire rapportée dans le questionnaire USP (87,2 % vs 90,6 % dans le groupe ABBREVO, p = 0,61), ou pour l’amélioration de la qualité de vie avec un score PGI-I entre 1 et 3 (82,1 % vs 86,8 % dans le groupe ABBREVO, p = 0,53). En revanche, plus de patientes étaient pleinement satisfaites avec un score PGI-I à 1 dans le groupe ABBREVO (67,9 % vs 46,2 % dans le groupe ALTIS, p = 0,03). La douleur postopératoire immédiate était significativement moins intense dans le groupe ALTIS que dans le groupe ABBREVO (score EVA moyen à 0,5 vs 1,3, p = 0,01) mais cette différence disparaissait à une semaine de la chirurgie. Les taux des autres complications étaient similaires dans les deux groupes. Conclusion Les résultats fonctionnels des bandelettes ALTIS et TVT-ABBREVO® semblent similaires dans le traitement de l’incontinence urinaire d’effort féminine

Synthèse d'époxyphosphonates alpha-chlorés, intermédiaires potentiels dans la préparation de l'analogue phosphoré du KDO, cible privilégiée dans la recherche de nouveaux antibiotiques

Les époxyphosphonatesex-chlorés ont été préparés par action de l'acide métachloroperbenzoïque (mCPBA) sur les vinylphosphonates ex- chlorés. L'isomérisation des époxyphosphonates est en cours d'étude. Les résultats de ces travaux seront appliqués au mannose pour la préparation du KDO phosphoré