Novel dilute nitride semiconductor materials for mid-infrared applications

A new approach to room temperature mid-infrared applications in the 3 -5 µm spectral range has been proposed through the development of novel dilute nitride materials. InAsN shows a large bandgap reduction with a small lattice mismatch when a small amount of nitrogen is introduced into the host InAs. Because the InAsN reported so far had generally poor crystalline quality and exhibited weak luminescence that quenched far below room temperature due to poorly understood localised states, the present thesis investigated the optimisation of the MBE growth of InAsN. The nitrogen incorporation was shown to be inversely dependent on the growth temperature, the growth rate and the arsenic flux, as was interpreted by a kinetic model. Luminescence from InAsN material showed two peaks, originating in bandgap-and localised state-related transitions. The emission related to the bandgap undergoes hardly any energy shift with increasing laser excitation power while it redshifts with increasing temperature. The emission from the localised states blueshifts with increasing laser excitation power and temperature. Rapid thermal annealing on InAsN layers improved the photoluminescence intensity and blueshifted the transition energy. InAsN was successfully grown with high crystalline quality. It showed strong photoluminescence which persisted up to room temperature with a reduced influence of the localised states and wavelength up to 4.5 µm was achieved when 2.5 % N were incorporated. An explanation of the temperature and nitrogen incorporation dependences of the InAsN bandgap was successfully proposed using Varshni's equation and an adapted band anticrossing model, where the nitrogen level energy is dependent on temperature and nitrogen composition. The crystalline quality and luminescence were both further improved by incorporating antimony into InAsN and strain balance in material for 4.2 µm applications was achieved with the novel InAsNSb alloy. A method to determine the composition of the quaternary was derived from bandgap models and lattice constant equation and the addition of antimony in InAsN was shown to enhance the nitrogen incorporation in InAsNSb. Finally, attempts at prototype InAsN and InAsNSb devices were reported, InAsNSb LEDs were demonstrated and electroluminescence from InAsNSb diodes at 3.88 µm at 4K was obtained

DEPRESSION AND PHYSICAL HEALTH, THE THERAPEUTIC ALLIANCE AND ANTIDEPRESSANTS

Background: In a two-year study we compared the efficacy of noradrenergic (duloxetine D) and serotonergic (escitalopram E) antidepressants with and without the addition of 100 mg acetylsalicylic acid (ASA) in subjects suffering from a major depressive episode (MDE). The results showed that the D + ASA (DASA) group improved more rapidly than the E + placebo (EP) subgroup. In particular, Hamilton Depression Scale (HDS) scores improved as early as two months, Clinical Global Impression (CGI) scores improved at five months, and remission rates were better. In the course of this study, we also investigated the role of the therapeutic relationship (alliance) on both the progress of the MDE, and patients’ mental and physical health. Subjects and methods: 40 people suffering from an MDE were randomly assigned to treatment groups. At the beginning of the study sociodemographic data were collected, and the Helping Alliance Questionnaire (HAQ) was completed. During the study, patients were regularly assessed using the HDS, CGI and the Short Form Health Survey (SF-12). Results: Subgroup comparisons revealed that HAQ scores are not correlated with HAD scores, but a correlation was found with remission rates (r=0.316*). Similarly, at all times, HAQ scores were correlated with physical health (p<0.05), which is in turn correlated with HDS and CGI scores. Conclusion: Physical health is linked to the level of depression. While the alliance with the patient is not directly correlated with the intensity of depression, is it correlated with their physical condition and its improvement. For patients, improving their physical health appears to be more important than improving their mental health. These observations must be confirmed

Les aides financières aux étudiants

Élaboré à partir d'une étude intitulée Les aides financières aux étudiants dans l'Union européenne, tendance et débats, cet article permet d'appréhender les composantes multiples qui sont à prendre en considération dans ce domaine selon les pays de l'Union européenne observés. Outre les principes de base sur lesquels reposent les différents systèmes d'aides et leurs objectifs, une analyse des données qui imposent une évolution est présentée.This article, based on a study entitled Financial help for students in the European Union, trends and issues, brings out the various components which have to be taken into account in this domain according to the country considered in the European Union. In addition to the basic principles on which the different systems of help and their objectives are founded, an analysis o f data is presented which will make changes necessary.Basado en un estudio titulado Las ayudas financieras a los estudiantes en la Unión Europea, usos y debates, este artículo permite abarcar las múltiples componentes que deben considerarse al estudiar este dominio según los países de la Unión Europea que se analicen. Además de los principios de base en los que descansan los diferentes sistemas de ayudas y sus metas, se presenta un análisis de los datos que imponen una evolución

Room temperature mid-infrared InAsSbN multi-quantum well photodiodes grown by MBE

Room temperature photoresponse in the mid-infrared spectral region is demonstrated from InAsSbN/InAs multi-quantum well photodiodes grown by nitrogen plasma assisted molecular beam epitaxy. The structural quality of the InAsSbN MQWs was ascertained in situ by reflection high energy electron diffraction and ex situ by high resolution x-ray diffraction and photoluminescence measurements. The extended long wavelength photoresponse is identified to originate from the electron–heavy hole (e1–hh1) and electron–light hole (e1–lh1) transitions in the InAsSbN MQW, with a cut off wavelength ~4.20 µm and peak detectivity D *  =  1.25  ×  109 cm Hz1/2 W−1

Reduced costs with bisoprolol treatment for heart failure - An economic analysis of the second Cardiac Insufficiency Bisoprolol Study (CIBIS-II)

Background Beta-blockers, used as an adjunctive to diuretics, digoxin and angiotensin converting enzyme inhibitors, improve survival in chronic heart failure. We report a prospectively planned economic analysis of the cost of adjunctive beta-blocker therapy in the second Cardiac Insufficiency BIsoprolol Study (CIBIS II). Methods Resource utilization data (drug therapy, number of hospital admissions, length of hospital stay, ward type) were collected prospectively in all patients in CIBIS . These data were used to determine the additional direct costs incurred, and savings made, with bisoprolol therapy. As well as the cost of the drug, additional costs related to bisoprolol therapy were added to cover the supervision of treatment initiation and titration (four outpatient clinic/office visits). Per them (hospital bed day) costings were carried out for France, Germany and the U.K. Diagnosis related group costings were performed for France and the U.K. Our analyses took the perspective of a third party payer in France and Germany and the National Health Service in the U.K. Results Overall, fewer patients were hospitalized in the bisoprolol group, there were fewer hospital admissions perpatient hospitalized, fewer hospital admissions overall, fewer days spent in hospital and fewer days spent in the most expensive type of ward. As a consequence the cost of care in the bisoprolol group was 5-10% less in all three countries, in the per them analysis, even taking into account the cost of bisoprolol and the extra initiation/up-titration visits. The cost per patient treated in the placebo and bisoprolol groups was FF35 009 vs FF31 762 in France, DM11 563 vs DM10 784 in Germany and pound 4987 vs pound 4722 in the U.K. The diagnosis related group analysis gave similar results. Interpretation Not only did bisoprolol increase survival and reduce hospital admissions in CIBIS II, it also cut the cost of care in so doing. This `win-win' situation of positive health benefits associated with cost savings is Favourable from the point of view of both the patient and health care systems. These findings add further support for the use of beta-blockers in chronic heart failure

Implications of serial measurements of natriuretic peptides in heart failure: insights from BIOSTAT‐CHF

No abstract available

Chapitre 1. Objectif et limites de l’analyse

L’objectif de cette étude est de dresser un panorama des instructions officielles pour l’enseignement initial de la lecture et de les présenter pays par pays. Par « instructions officielles », on entend tous les textes et documents produits par les autorités éducatives, c’est-à-dire le ministère dans la plupart des pays. Par enseignement initial, on entend l’enseignement dispensé durant les deux premières années d’instruction formelle. On s’intéressera donc aux activités d’initiation et d’ens..