Women Principals of Jewish Secular High Schools in Israel: Access and Progress

This quantitative investigation focused on women high school principals at Jewish secular schools throughout Israel. Despite challenges, Israeli women have succeeded in obtaining over half of the principal positions at Jewish secular high schools, but the degree to which there is equal gender access to leadership roles in the school system remains unclear. This study examined whether there was clustering of women in high school principal positions in certain geographical areas, the process by which these women obtained principal positions, what obstacles the women overcame, and an analysis if respondents differed by district in terms of their career paths, career breaks, and military experiences. This study showed that although women are in principal positions in equal or greater numbers as men depending on the region, women had a different path than men to obtain this role. The key findings in this research were that 89.5% of women principals were able to return at the same level prior to taking a career break and that 31.8% of female principals had male mentors

Caractérisation statistique d'une assemblée de nanotubes en imagerie microscopique

Dans le domaine des nanotechnologies, de nombreux dispositifs incorporant des nano-objets sont développés. Les différents procédés de fabrication sont en général validés à l'aide d'images de microscopie souvent interprétées de manière relativement qualitative. Une caractérisation systématique et automatique de ces observations permettrait des comparaisons quantitatives et objectives. Nous nous intéressons en particulier à des nanomembranes en nanotubes de carbone destinées à des applications en instrumentation. Nous proposons une chaîne complète de traitement d'images de microscopie électronique à balayage. Les principales étapes sont un débruitage anisotrope, une amélioration de contraste et une segmentation utilisant la morphologie mathématique ainsi qu'une estimation de l'orientation locale de filaments grâce au tenseur de structure. Nous abordons aussi l'extraction de filaments individuels. Cette approche n'implique aucune intervention de l'utilisateur et peut être utilisée automatiquement sur des ensembles de plusieurs centaines d'images. Nous obtenons notamment pour la première fois les histogrammes d'orientation de nanotubes constituant des nanomembranes et accédons ainsi à une mesure objective de la qualité de l'alignement des nanotubes, essentielle pour la physique du capteur

Directional emission of stadium-shaped micro-lasers

The far-field emission of two dimensional (2D) stadium-shaped dielectric cavities is investigated. Micro-lasers with such shape present a highly directional emission. We provide experimental evidence of the dependance of the emission directionality on the shape of the stadium, in good agreement with ray numerical simulations. We develop a simple geometrical optics model which permits to explain analytically main observed features. Wave numerical calculations confirm the results.Comment: 4 pages, 8 figure

Trace formula for dielectric cavities II: Regular, pseudo-integrable, and chaotic examples

Dielectric resonators are open systems particularly interesting due to their wide range of applications in optics and photonics. In a recent paper [PRE, vol. 78, 056202 (2008)] the trace formula for both the smooth and the oscillating parts of the resonance density was proposed and checked for the circular cavity. The present paper deals with numerous shapes which would be integrable (square, rectangle, and ellipse), pseudo-integrable (pentagon) and chaotic (stadium), if the cavities were closed (billiard case). A good agreement is found between the theoretical predictions, the numerical simulations, and experiments based on organic micro-lasers.Comment: 18 pages, 32 figure

Sense-City, un démonstrateur réaliste de technologies innovantes pour la ville durable

International audienceSense-City, un démonstrateur réaliste de technologies innovantes pour la ville durabl

Highly reproducible, hysteresis-free, flexible strain sensors by inkjet printing of carbon nanotubes

In order to build upon the exceptional interest for flexible sensors based on carbon nanotube networks (CNNs), the field requires high device-to-device reproducibility. Inkjet printing has provided outstanding results for flexible ohmic sensors in terms of reproducibility of their resistance. However, the reproducibility of the sensitivity, the most critical parameter for sensing application, has been only marginally assessed. In the present paper, CNN based resistive strain sensors fabricated by inkjet-printing on flexible Ethylene Tetrafluoroethylene (EFTE) sheets are presented. The variability on the device initial resistance is studied for 5 different batches of sensors from 3 to 72 devices each. The variability ranges between 8.4% and 43% depending on the size of the batches, with a 20% average. An 8-device batch with 15% variability on initial resistance is further studied for variability on the strain and thermal sensitivity. Standard deviation values are found to be as low as 16% on the strain sensitivity and 8% on the temperature sensitivity. Moreover, the devices are hysteresis free, a rare achievement for CNT strain sensors on plastics

Circular dielectric cavity and its deformations

The construction of perturbation series for slightly deformed dielectric circular cavity is discussed in details. The obtained formulae are checked on the example of cut disks. A good agreement is found with direct numerical simulations and far-field experiments.Comment: 17 pages, 12 figure

Dependence of far-field characteristics on the number of lasing modes in stadium-shaped InGaAsP microlasers

We study spectral and far-field characteristics of lasing emission from stadium-shaped semiconductor (InGaAsP) microlasers. We demonstrate that the correspondence between a lasing far-field emission pattern and the result of a ray simulation becomes better as the number of lasing modes increases. This phenomenon is reproduced in the wave calculation of the cavity modes.Comment: 7 pages, 3 figure

Oxidation-Based Continuous Laser Writing in Vertical Nano-Crystalline Graphite Thin Films

Nano and femtosecond laser writing are becoming very popular techniques for patterning carbon-based materials, as they are single-step processes enabling the drawing of complex shapes without photoresist. However, pulsed laser writing requires costly laser sources and is known to cause damages to the surrounding material. By comparison, continuous-wave lasers are cheap, stable and provide energy at a more moderate rate. Here, we show that a continuous-wave laser may be used to pattern vertical nano-crystalline graphite thin films with very few macroscale defects. Moreover, a spatially resolved study of the impact of the annealing to the crystalline structure and to the oxygen ingress in the film is provided: amorphization, matter removal and high oxygen content at the center of the beam; sp2 clustering and low oxygen content at its periphery. These data strongly suggest that amorphization and matter removal are controlled by carbon oxidation. The simultaneous occurrence of oxidation and amorphization results in a unique evolution of the Raman spectra as a function of annealing time, with a decrease of the I(D)/I(G) values but an upshift of the G peak frequency