Les agrégats multi-échelles (sulfure de zinc: ZnS, ...) ont des propriétés physiques et physicochimiques présentant un grand intérêt industriel (industrie pharmaceutique, matériau, environnement...). L'objectif général de cette thèse est de caractériser ces agrégats multi-échelles par une méthode optique d'une part, et par une étude géométrique d'autre part. Le but est de trouver des relations simples entre propriétés optiques et géométriques. Les résultats présentés sont valables pour tout matériau à haut indice de réfraction.Ce travail comporte une première étape de modélisation en étudiant tout d'abord des modèles simples d'agrégats multi-échelles (agencement ordonné de particules élémentaires sphériques). Différents agrégats sont alors géométriquement modélisés suivant des paramètres de construction prédéfinis (volume global des agrégats, rayon des particules primaires...). Une analyse préliminaire optique puis une analyse géométrique sont alors effectuées afin de déterminer les paramètres respectifs à étudier: la section efficace moyenne de diffusion (...), calculée au moyen d'une extension de la théorie de Mie (GMM pour Generalized Multiparticle Mie) d'Y-L Xu, et des caractéristiques géométriques spécifiques (volume de matière, compacité...).Une seconde étape consiste à étudier les variations de la valeur de ... en fonction de celles des paramètres géométriques des agrégats. Des relations caractérisant ces variations sont établies. Enfin, une expression approchées pour la valeur de ... est recherchée sous la forme d'une loi de puissance, reposant sur des méthodes optiques approchées existantes et sur la sélection de caractéristiques géométriques pertinentes. Le modèle mis en place est robuste et présente un compromis entre précision et complexité. Le travail réalisé ouvre diverses perspectives comme la confrontation du modèle mathématique théorique obtenu, avec l'expérience.

Este trabajo resuelve el problema de gran interés para la industria aeronáutica: el cálculo de la sección recta (RCS) de blancos radar complejos en tiempo real. Para ello basta una estación de trabajo con un acelerador grafico 3-d hardware en lugar de los super-ordenadores vectoriales que requieren los métodos clásicos. El método desarrollado totalmente original e innovador, consiste en procesar gráficamente una imagen del blanco presente en la pantalla de la estación grafica. Con ello se consigue que el tiempo de cpu sea independiente del tamaño y complejidad del blanco, con lo que su principal aplicación es la estimación rápida de la RCS de blancos radar complejos. Este método, al que hemos denominado "procesado grafico", implementa las aproximaciones asintóticas de alta frecuencia que permiten obtener las principales contribuciones a la RCS: óptica física, para la reflexión en superficies; condiciones de contorno de impedancia, para la reflexión en recubrimientos absorbentes radar (RAM), método de las corrientes equivalentes para la disposición en aristas y un método grafico de iluminación global (radiosity) para las reflexiones múltiples entre superficies. Los resultados de este trabajo hacen posible, por vez primera, el diseño interactivo de formas de baja RCS "stealth" con una estación de trabajo, por lo que se ha conseguido una herramienta software para la industria aeronáutica de gran eficiencia y potencialidad en sus aplicaciones.

This paper examines the determinants of profitability using operations strategy, productivity, and service measures in the context of the U.S. domestic airline industry. Data on ten carriers was collected on a quarterly basis between 1995 and 2007. An analysis is performed separately on data prior and post 9/11 attack. It is found that operations strategy and productivity measures are significant both before and after the 9/11 attack, whereas service measures are only significant before 9/11. Some managerial implications are provided. Additionally, it is found that the profitability of full-service carriers is improving faster than low-cost carriers after 9/11.

The photoionization of the beryllium-like isoelectronic series has been studied. The bound state wave functions of the target ions were built with CIV3 program. The relativistic Breit-Pauli R-matrix method was used to calculate the cross sections in the photon energy range between the ionization threshold and 1s24f7/2 threshold for each ion. For the total cross sections of Be, B+, C+2, N+3, and O+4, our results match experiment well. The comparison between the present work and other theoretical works are also discussed. We show the comparison with our LS results as it indicates the importance of relativistic effects on different ions. In the analysis, the resonances converging to 1s22lj and 1s23lj were identified and characterized with quantum defects, energies and widths using the eigenphase sum methodology. We summarize the general appearance of resonances along the resonance series and along the isoelectronic sequence. Partial cross sections are also reported systematically along the sequence. All calculations were performed on the NERSC system.

Photoionization cross section calculations are performed for the ground ([Ne]3s23p63d 2D ) and the first two excited ([Ne]3s23p63d 2D and [Ne]3s23p64s 2S ) states of potassium-like transition metal ions (Sc+2, Ti+3, V+4, Cr+5, Mn+6, Fe+7), along with photoionization calculations for K-like Ca+ ions in the ground ([Ne]3s23p64s 2S ) state and the first two excited ([Ne]3s23p63d 2D and [Ne]3s23p63d 2D ) states. The discrete N-electron final state ion system orbitals are generated using the computer program AUTOSTRUCTURE; 24 configurations are included in the configuration-interaction (CI) calculation for transition metal ions, and 30 configurations for the case of Ca+ ions. The initial and final (N+1)-electron wavefunctions are generated using R-matrix along with photoionization cross sections. In addition to the non-relativistic (LS-coupling) R-matrix, we have used the relativistic (Breit-Pauli) R -matrix method to carry out these calculations to focus on relativistic effects. Relativistic and non-relativistic results are compared to demonstrate the influence of relativistic effects. The prominent 3p → 3d giant resonances are analyzed and identified, and our calculated positions and widths are compared with experimental results for K-like ions such as Ca+, Sc+2 and Ti+3. In the case of lower Z (22  Z  20) ions (Ca+, Sc+2 and Ti+3), the photoionization cross section spectra are dominated by the giant (3p  3d excitation) resonances, while in cases of higher Z (26  Z  23) ions (V+4, Cr+5, Mn+6 and Fe+7), the 3p  3d resonances lie below the ionization threshold, and the cross sections are dominated by 3p53d nd and 3p53d n’s Rydberg series of resonances. Comparison of the Ca+, Sc+2 and Ti3+ results with available theoretical and experimental data shows good agreement.

By analyzing ISAR images, the characteristics of military platforms with respect to radar visibility can be evaluated. The method, which is based on the Discrete-Time Fourier Transform (DTFT), that is currently used to calculate the ISAR images requires large computations efforts. This thesis investigates the possibility to replace the DTFT with the Fast Fourier Transform (FFT). Such a replacement is not trivial since the DTFT is able to compute a contribution anywhere along the spatial axis while the FFT delivers output data at fixed sampling, which requires subsequent interpolation. The interpolation leads to a difference in the ISAR image compared to the ISAR image obtained by DTFT. On the other hand, the FFT is much faster. In this quality-and-time trade-off, the objective is to minimize the error while keeping high computational efficiency. The FFT-approach is evaluated by studying execution time and image error when generating ISAR images for an aircraft model in a controlled environment. The FFT method shows good results. The execution speed is increased significantly without any visible differences in the ISAR images. The speed-up- factor depends on different parameters: image size, degree of zero-padding when calculating the FFT and the number of frequencies in the input data.

This paper examines the determinants of profitability using operations strategy, productivity, and service measures in the context of the U.S. domestic airline industry. Data on ten carriers was collected on a quarterly basis between 1995 and 2007. An analysis is performed separately on data prior and post 9/11 attack. It is found that operations strategy and productivity measures are significant both before and after the 9/11 attack, whereas service measures are only significant before 9/11. Some managerial implications are provided. Additionally, it is found that the profitability of full-service carriers is improving faster than low-cost carriers after 9/11.

The main purpose of this stydy was to evaluate the Aurora clinic (for women afraid of birth/delivery) in the south of Sweden. Questionnaires were sent to 197 women who had contact with the Aurora clinic during 2007 and 2008. The group of participants contained both pregnant women and women who have given birth. A total of 136 women replied. The results showed that both the average age and the level of education of the women were high. Nulli-paras and multi-paras had different reasons for fearing delivery. The study also showed that most women felt that the contact with an Aurora midwife helped them to feel secure and to be better prepared before delivery, that the midwife understood them and took them seriously and that the content of the meetings was satisfactory. Three out of four women, who initially wished for a caesarean section, subsequently accepted a normal delivery. This study supports previous research that shows the importance of the supportive conversation provided at the Aurora clinic for women with fear of delivery.

Today around 28 000 women originally from countries where FGM is practised, are living in Sweden. Many of them are at childbearing age which means that knowledge about FGM and its consequences is of outmost importance during delivery. The aim of this study is to describe current research on how to manage the delivery, regarding deinfibulation and the following stitching as well as the risk of complications when the labouring woman is mutilated. This review of literature is based on 12 scientific articles published between years 1989 – 2005. Five different databases have been searched with use of a large number of keywords.The review found that no scientific research has been carried out that describes how deinfibulation and following stitching should be managed when the woman is mutilated. All available articles within this area are referring to best practice only. The review also found that the conclusions of the studies are contradictory. The majority, however, show an increased frequency for prolonged labour that could be related to FGM. The three largest studies also show an increased rate of caesarean section among mutilated women. In the few studies that examine haemorrhage, the majorities show an increased tendency to bleed, that could be related to FGM. Several articles emphasize the importance of good routines for deinfibulation to reduce the risk for complications.In summary it can be established that due to methodological problems in many studies, no reliable conclusion can be made that the researched complications exists to a greater extent when the woman is mutilated

The increase in foreign students in countries such as the US, the UK and Francesuggests that the international ‘education industry’ is growing in importance. Thepurpose of this paper is to investigate the empirical determinants of internationalstudent mobility. A secondary purpose is to give tentative policy suggestions to hostcountry, source country and also to provide some recommendations to students whowant to study abroad. Using pooled cross-sectional time series data for the US overthe time period 1993-2006, we estimate an econometric model of enrolment rates offoreign students in the US. Our results suggest that tuition fees, US federal support ofeducation, and the size of the ‘young’ generation of source countries have asignificant influence on international student mobility. We also consider other factorsthat may be relevant in this context.