Échantillonneur pour analyse simultanée des événements X, Y et XY

En analyse biparamétrique, il est souvent nécessaire de connaître en plus du spectre X Y les deux spectres simples X et Y sans tenir compte des corrélations qui existent entre eux. Il est important d'utiliser les mêmes codeurs pour les deux types de spectres. L'augmentation du temps mort qui en résulte est réduite par une méthode d'échantillonnage. Le principe de la méthode et la logique des circuits permettant l'analyse simultanée des informations simples et corrélées sont décrits

Passive coherent discriminator using phase diversity for the simultaneous measurement of frequency noise and intensity noise of a continuous-wave laser

The frequency noise and intensity noise of a laser set the performance limits in many modern photonics applications and, consequently, must often be characterized. As lasers continue to improve, the measurement of these noises however becomes increasingly challenging. Current approaches for the characterization of very high-performance lasers often call for a second laser with equal or higher performance to the one that is to be measured, an incoherent interferometer having an extremely long delay-arm, or an interferometer that relies on an active device. These instrumental features can be impractical or problematic under certain experimental conditions. As an alternative, this paper presents an entirely passive coherent interferometer that employs an optical 90° hybrid coupler to perform in-phase and quadrature detection. We demonstrate the technique by measuring the frequency noise power spectral density of a highly-stable 192 THz (1560 nm) fiber laser over five frequency decades. Simultaneously, we are able to measure its relative intensity noise power spectral density and characterize the correlation between its amplitude noise and phase noise. We correct some common misconceptions through a detailed theoretical analysis and demonstrate the necessity to account for normal imperfections of the optical 90° hybrid coupler. We finally conclude that this passive coherent discriminator is suitable for reliable and simple noise characterization of highly-stable lasers, with bandwidth and dynamic range benefits but susceptibility to additive noise contamination.V Michaud-Belleau, H Bergeron, P S Light, N B Hébert, J D Deschênes, A N Luiten and J Genes

Impact de la pandémie de Covid-19 sur la santé et le développement des jeunes en Suisse - Quel rôle pour les médecins ? [Impact of the COVID-19 pandemic on adolescent health and development: a role to play for physicians]

This article summarizes the conclusion of a two-days interprofessional online workshop held under the auspices of the Brocher Foundation. The objectives were to review the impact of COVID on adolescent health and development and to generate some key responses to the situation. The pandemic has severely affected the mental health of a large proportion of adolescents and has significantly reduced access to health care. It has as well disturbed the school education of vulnerable youngsters and decreased social contacts with adults and peers. In the future, authorities should better consider the rights of young people and request their opinion and participation in decision making. Physicians should systematically explore their young patients' opinions and queries regarding the COVID and address problematic situations such as family conflicts, misuse of internet or risky behaviour

The Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory is a second generation water Cherenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector is unique in its use of D2O as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates. In this paper the physical properties, construction, and preliminary operation of the Sudbury Neutrino Observatory are described. Data and predicted operating parameters are provided whenever possible.Comment: 58 pages, 12 figures, submitted to Nucl. Inst. Meth. Uses elsart and epsf style files. For additional information about SNO see http://www.sno.phy.queensu.ca . This version has some new reference

Detectable clonal mosaicism and its relationship to aging and cancer

In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases

Acquisition et traitement de données par le système ESTER/IBM 1800

Un ensemble d'acquisition et de traitement de données utilisant un ordinateur IBM 1800 est décrit. On explique comment le système d'exploitation permet à plusieurs équipes indépendantes de partager l'utilisation de l'ordinateur pour l'acquisition et le traitement de données en temps réel

Visualisation et sortie de spectres enregistrés dans un IBM 1800

La visualisation « programmée » utilise trop de temps pour renouveler les tables de sortie lorsque les données à visualiser évoluent rapidement. Nous avons réalisé une visualisation « semi-câblée » permettant l'acquisition, le traitement et la visualisation simultanément, et enfin une visualisation « câblée » pour augmenter la place mémoire réservée au traitement

Visualisation et sortie de spectres enregistrés dans un IBM 1800

The "software visualisation" needs too much time to rewrite the data tables in the acquisition mode. We have developed a "hardware-software" visualisation system which permits simultaneously data acquisition, processing and display. A "hardware visualisation" increasing the size of the area available for the data processing is described.La visualisation « programmée » utilise trop de temps pour renouveler les tables de sortie lorsque les données à visualiser évoluent rapidement. Nous avons réalisé une visualisation « semi-câblée » permettant l'acquisition, le traitement et la visualisation simultanément, et enfin une visualisation « câblée » pour augmenter la place mémoire réservée au traitement