Le problème de la modélisation de la diffusion d'une onde électromagnétique par une surface rugueuse naturelle (océan, sable...) ou artificielle (routes...) intervient dans de nombreuses applications radar. La nature géométrique et physique des contributeurs ainsi que leur répartition sur la surface entraînent souvent des interactions difficiles à quantifier par des méthodes exactes et/ou asymptotiques numériques. <br />D'autre part, nous avons établi, à partir de nos recherches bibliographiques dans le domaine des surfaces rugueuses, que la diffusion totale par de telles surfaces est la somme d'une diffusion de surface (fonction des irrégularités sur la surface) et d'une diffusion de volume (due aux inclusions dans le sol).<br /><br />Au cours de cette thèse, nous avons développé une méthode analytique rigoureuse de calcul de la puissance totale diffusée par des sols rugueux basée sur l'utilisation conjointe de la Méthode de l'Equation Intégrale ou IEM (diffusion de surface) et de la Théorie du Transfert Radiatif (diffusion de volume). <br /><br />Dans nos applications, nous nous sommes intéressés à des surfaces rugueuses en asphalte et en béton. Nous avons évalué le coefficient de rétrodiffusion en considérant aussi le cas rarement traité de l'incidence rasante (pour des applications radar d'assistance à la conduite). Nous avons ensuite généralisé cette étude au comportement de la diffusion bistatique (diffusion dans des directions autres que la direction d'incidence).<br /><br />Une autre partie intéressante de ces travaux a concerné l'évaluation du comportement d'un objet dans son environnement proche. Il s'avère en effet nécessaire, sous certaines incidences, de prendre, de plus, en compte la contribution du couplage entre un objet et son environnement immédiat. Les interactions directes onde électromagnétique - objet sont évaluées par les modules de calcul de la surface équivalente radar (SER) d'objets complexes 3D réalisés au laboratoire. L'environnement (surface rugueuse dans notre cas) est caractérisé par son coefficient de diffusion bistatique déterminé par les méthodes électromagnétiques étudiées et précitées. Ainsi, il a été possible d'élaborer une méthode de calcul de la SER d'un objet complexe 3D en tenant compte de l'influence de son environnement naturel.

L'objectif de cette étude est d'analyser le gradient des contraintes résiduelles induites par le traitement de choc laser (CL) sur 2 alliages d'aluminium (6056-T4 et 2050-T8) par la diffraction des rayons X (DRX) et par modélisation numérique en éléments finis, en portant une attention particulière à l'extrême surface du matériau. Pour étudier le gradient des contraintes résiduelles (CR) à l'extrême surface (moins de 10 μm), deux méthodes d'analyse par DRX en faible incidence (sin²ψ* et multi-réflexions) ont été adaptées et appliquées. Les deux méthodes ont été testées avec succès et ont permis pour la premières fois, d'accéder aux états mécaniques proches de la surface après CL. Un modèle de simulation numérique en 3D de l'état mécanique induit par choc-laser a également été développé au cours de cette étude. L'utilisation de chargements P=f(t) valides et de conditions aux limites réalistes (élément infinis en bord de massif) a permis d'estimer les déformations et les contraintes résiduelles introduites par un ou par plusieurs impacts laser. Différentes améliorations ont pu être apportées au modèle, comme la prise en compte de comportements distincts pour les couches superficielles, et le matériau à cœur. Le modèle a été appliqué à différentes conditions expérimentales (taux de recouvrement, diamètre d'impact et pression variables) et a pu être confronté avec succès en expérience, que ce soit pour la simulation de mono-impact laser ou pour la simulation de multi-impacts. L'approche numérique nous a également permis d'évaluer l'hétérogénéité de la distribution de contraintes résiduelles en surface du matériau.

Les victimes d'accident de la route sont recensées par les forces de l'ordre, en France, et dans la plupart des pays. L'enregistrement des blessés non-décédés est incomplet et biaisé (biais de sélection et de classement de la gravité). Un registre médical couvre le département du Rhône. La coexistence des recensements policier et médical permet par capture-recapture d'estimer un bilan exhaustif au niveau rhodanien, et ainsi d'estimer les facteurs de correction des données policières. En faisant l'hypothèse d'homogénéité, sur le territoire national, des pratiques policières d'enregistrement des blessés, nous appliquons les coefficients de correction aux données policières nationales, en redressant sur les facteurs de biais. Les effectifs annuels moyens sur 1996-2004 sont alors estimés à 514 000 blessés dont 61 000 blessés graves, soit 3,7 et 2,2 fois les décomptes des forces de l'ordre. Les blessés avec séquelles lourdes sont estimés à 8000 annuellement, soit autant que les tués.

<p>From being a rare disease in the early 1900s, lung cancer is today the most common forms of cancer worldwide. This development is due to the gradual uptake of cigarette smoking in different populations and birth cohorts during the past 75 years. In spite of different modes of treatment, survival is still poor and surgery remains the prerequisite for cure. </p><p>National data from the Swedish Cancer Register for the 35-year period 1958-1994 were analysed to estimate the effects of birth cohort, year of diagnosis (period) and age at diagnosis on the time trends in lung cancers. Early mortality, complications, major morbidity during the first 30 days, quality of life and long term survival after lung cancer surgery were assessed to estimate the significance of pre-surgical and tumour-related risk factors. Also, effects of delay in diagnosis and treatment among patients with non-small cell lung cancer were examined.</p><p>The main results indicate that the overall age-adjusted incidence of lung cancer in Sweden has stabilised in men during the last two decades but has been increasing continuously in women. The fastest rate increase was noted among the youngest women and the incidence of adenocarcinoma is increasing in both sexes. Our results show low early mortality and morbidity after lung cancer surgery. Furthermore, quality of life was comparable with that of CABG patients postoperatively. However, patients with reduced lung capacity and those undergoing pneumonectomy should be treated with great care, as they run a considerable risk of major complications, impaired quality of life or death during the first 30 days postoperatively. Tumour stage (TNM) is the best prognostic indicator for long-term survival following radical surgery, underlying the importance of accurate surgical staging. Factors such as impaired preoperative lung function, older age, and major complications after surgery all negatively influence survival. Current smokers as a group run a significant risk of an adverse outcome (major complication or death), impaired mental health and shortened survival after lung cancer surgery. Waiting time for diagnosis and treatment of lung cancer was longer than recommended; especially among those surgically treated, but prolonged delay did not influence survival adversely.</p>

<p>In a prospective population-based study in Stockholm County, 1998-2000, the incidence of retinopathy of prematurity (ROP) was investigated and was found to be 36% in prematurely-born infants with a birth weight of ≤ 1500 grams. Compared to a study performed ten years ago, the overall incidence was unchanged, but was reduced in “mature” infants and increased in immature ones. The incidence of ROP was 25% in infants with a gestational age of ≤ 32 weeks at birth. The main risk factors for ROP were the gestational age at birth, followed by the birth weight. Current guidelines for ROP screening in Sweden were modified.</p><p>A 10-year follow-up study of the ophthalmological findings in prematurely-born children, previously included in a prospective population-based incidence study of ROP, was performed. The children were compared with full-term ones. </p><p>Prematurely-born children ran a four times higher risk of refractive errors than full-term ones. The cryotreated children had the highest risk, but those without ROP also had more refractive errors than the full-terms. Within the group of prematurely-born children, the cryotreated ones had the highest prevalence of myopia, astigmatism and anisometropia, but no difference was found regarding hypermetropia.</p><p>The visual acuity of prematurely-born children was poorer than that of the full-terms. The cryotreated children and those with neurological complications had the most marked reduction, but the children without ROP and neurological findings also had a poorer visual outcome than the full-terms. The prevalence of visual impairment was 1.8% among the prematurely-born children, and was due to ROP in half the cases and cerebral lesions in the others. </p><p>The cryotreated children had constricted peripheral visual fields compared to the untreated prematurely-born and full-term children. The central visual fields tended to be reduced in the prematurely-born children compared to the full-terms, but no difference was observed within the preterm group.</p>

From being a rare disease in the early 1900s, lung cancer is today the most common forms of cancer worldwide. This development is due to the gradual uptake of cigarette smoking in different populations and birth cohorts during the past 75 years. In spite of different modes of treatment, survival is still poor and surgery remains the prerequisite for cure. National data from the Swedish Cancer Register for the 35-year period 1958-1994 were analysed to estimate the effects of birth cohort, year of diagnosis (period) and age at diagnosis on the time trends in lung cancers. Early mortality, complications, major morbidity during the first 30 days, quality of life and long term survival after lung cancer surgery were assessed to estimate the significance of pre-surgical and tumour-related risk factors. Also, effects of delay in diagnosis and treatment among patients with non-small cell lung cancer were examined. The main results indicate that the overall age-adjusted incidence of lung cancer in Sweden has stabilised in men during the last two decades but has been increasing continuously in women. The fastest rate increase was noted among the youngest women and the incidence of adenocarcinoma is increasing in both sexes. Our results show low early mortality and morbidity after lung cancer surgery. Furthermore, quality of life was comparable with that of CABG patients postoperatively. However, patients with reduced lung capacity and those undergoing pneumonectomy should be treated with great care, as they run a considerable risk of major complications, impaired quality of life or death during the first 30 days postoperatively. Tumour stage (TNM) is the best prognostic indicator for long-term survival following radical surgery, underlying the importance of accurate surgical staging. Factors such as impaired preoperative lung function, older age, and major complications after surgery all negatively influence survival. Current smokers as a group run a significant risk of an adverse outcome (major complication or death), impaired mental health and shortened survival after lung cancer surgery. Waiting time for diagnosis and treatment of lung cancer was longer than recommended; especially among those surgically treated, but prolonged delay did not influence survival adversely.

In a prospective population-based study in Stockholm County, 1998-2000, the incidence of retinopathy of prematurity (ROP) was investigated and was found to be 36% in prematurely-born infants with a birth weight of ≤ 1500 grams. Compared to a study performed ten years ago, the overall incidence was unchanged, but was reduced in “mature” infants and increased in immature ones. The incidence of ROP was 25% in infants with a gestational age of ≤ 32 weeks at birth. The main risk factors for ROP were the gestational age at birth, followed by the birth weight. Current guidelines for ROP screening in Sweden were modified. A 10-year follow-up study of the ophthalmological findings in prematurely-born children, previously included in a prospective population-based incidence study of ROP, was performed. The children were compared with full-term ones. Prematurely-born children ran a four times higher risk of refractive errors than full-term ones. The cryotreated children had the highest risk, but those without ROP also had more refractive errors than the full-terms. Within the group of prematurely-born children, the cryotreated ones had the highest prevalence of myopia, astigmatism and anisometropia, but no difference was found regarding hypermetropia. The visual acuity of prematurely-born children was poorer than that of the full-terms. The cryotreated children and those with neurological complications had the most marked reduction, but the children without ROP and neurological findings also had a poorer visual outcome than the full-terms. The prevalence of visual impairment was 1.8% among the prematurely-born children, and was due to ROP in half the cases and cerebral lesions in the others. The cryotreated children had constricted peripheral visual fields compared to the untreated prematurely-born and full-term children. The central visual fields tended to be reduced in the prematurely-born children compared to the full-terms, but no difference was observed within the preterm group.

In an unselected series of mentally retarded children in the county of Västerbotten, Sweden, the annual incidence of children with severe mental retardation (SMR) (IQ &lt; 50) and alive at the age of one year decreased from 5.3 per 1,000 in 1959 - 1963 to 3.1 per 1,000 in 1967 -1970. This was mainly due to a decrease in the incidence of Down's syndrome. In parallel the proportion of mothers 35 years of age or more at the birth of the child decreased significantly. The prevalence of children with SMR in 1976 was 3.5 per 1,000. The main cause of the SMR was prenatal in 70 percent, perinatal in 8 percent and postnatal in 1 percent. The cause of the SMR was untraceable in 20 percent of the cases. Associated CNS-handicaps occurred in 52 percent of the cases. The annual incidence of mildly mentally retarded children (IQ 50 - 69) registered at the Bureau for Provision and Services for Mentally Retarded was 4.2 per 1,000 and the prevalence in 1979 was 3.8 per 1,000. The cause of the mild mental retardation (MMR) was untraceable in 43 percent. Prenatal causes were identified in as many as 43 percent. Perinatal causes were found in 7 percent and postnatal causes in 5 percent of the cases. Associated CNS-handicaps occurred in 30 percent of the cases.A syndrome of mental retardation with X-linked inheritance not recognized previously in Sweden was characterized clinically (mainly in boys, machro-orchidism, verbal disabilities) and cytogenetically (a fragile site on the X-chromosomes seen after cui turing in special folic acid deficient media) and found to have a prevalence of 6 percent in the population of severely mentally retarded boys. This makes this syndrome the next most common cause of SMR in boys after Down's syndrome. The chromosomal fragility was also identified in female carriers, which has implications for genetic counselling.Through identification of an untreated Phenylketonurie mother giving birth to five severely mentally retarded children, attention was focused on the risks for the fetus of the growing number of Phenylketonurie women identified neonatally and treated di etarily but untreated after the age of 10 - 15 years.Great improvement in intellectual and social ability was seen in a boy with phenylketonuria although the dietary treatment was not introduced until the age of eight years.Heavy irradiation of a fetus late in gestation caused mental retardation, microcephaly, stunted growth, and eye and teeth abnormalities, although such abnormalities are thought not to result from irradiation after 20 weeks of pregnancy. / <p>Endast s.1-71: sammanfattningen (kappan) i fulltexten.</p><p>Ej med i fulltexten s.72-145: 7 delar.</p> / digitalisering@umu

<p>Across the world, physical inactivity was found to be associated with cardiovascular and chronic diseases of lifestyle which often leads to an increased rate of various physical disabilities andpremature death. To combat these high incidences of chronic diseases of lifestyle, WHO strongly encourages people to become physically active on a daily basis to reduce the risk of&nbsp / premature death. Running has thus become the preferred choice of physical activity by thousands of people to help improve their overall health and wellbeing. Apart from the health benefits&nbsp / that running provides, it can also predispose the runner to potential injury especially when runners follow an inappropriate training programme and have inadequate knowledge about factors causing injury. Therefore, baseline data about the prevalence, incidence of injury and the identification of the aetiological factors associated with running injuries are needed to develop and&nbsp / implement preventative programmes to allow runners to optimally perform in training and races without injury. In South Africa, there is limited research available on the incidence of injury in runners yet there is an annual increase in participation in races such as Two Oceans and Comrades marathon which could lead to an increase in the number of running injuries.Thus, the purpose of this study was to determine the incidence of injuries and identify the various risk factors that are associated with injuries in road runners at a local athletic club. Methods: A prospective cohort study design over a 16 week period using quantitative research methods was used. A sample of 50 runners had consented to participate in the study. The participants had to complete a self-administered questionnaire and clinical measurements of BMI, Q-angle, leglength, muscle strength of lower leg and ROM of hip and knee were recorded. The participants had&nbsp / to complete an injury report form to record any new injuries sustained over the 16 week period of the study. Statistical Package for Social Sciences (SPSS) version 18 and software SAS v9 (SAS Institute Inc., Cary, NC, USA) was used for data capturing and analysis. Descriptive and inferential statistics were done to summarize the data and was expressed as frequencies, percentages, means and standard deviations. Injury prevalence and cumulative incidence was calculated as a proportion rate along with 95% confidence interval. The Poisson regression model was used to analyse the association between running injury and the independent variables of interest such as demographics, anthropometric measurements, training methods, running experience and&nbsp / previous injury. The alpha level was set as p&lt / 0.05. Results: The study found that the majority (92%) of the participants (n=46) sustained running injuries in the past prior to the study. A total of 16 participants sustained a number of 50 new injuries over the 16 week study period. Thus the prevalence rate of injuries was 32%. The incidence rate of injuries for this study was 0.67 per&nbsp / 1000km run at a 95% confidence interval of 0.41, 1.08. Furthermore, the most common location of new injuries reported were the calf (20%) and the second most common location was the&nbsp / knee (18%). PFPS was the most common type of knee injury diagnosed, followed by lumbar joint sprain. The results showed that none of the identified factors (running distance, stretching, age, Q-angle, BMI, running experience, leg-length discrepancy and previous running injuries) were directly associated with running injuries. However, a marginal significance was found for&nbsp / running distance (p = 0.08) and leg length discrepancy (p = 0.06). Conclusions: The study found a high prevalence and incidence rate of injury thus the need for preventative programmes have been highlighted. There was no statistical significance found between the identified factors and risk of injury however, there was clinical relevance found between factors identified. One major&nbsp / limitation was the small sample of participants and the short duration of study period. Thus, future research is needed to further determine possible factors associated with running injuries over a longer period and including a larger sample. The results of the study will be made available to all the stakeholders (runners, coaches and medical team) to implement in athletic club. </p>

Anhand einer prospektiven epidemiologischen Verlaufsstudie an einer repräsentativen Bevölkerungsstichprobe von ursprünglich 14- bis 17jährigen Jugendlichen (N=1395) werden die Häufigkeit und die Verlaufsmuster des Konsums, des Mißbrauchs und der Abhängigkeit von Cannabis untersucht. Die Jugendlichen wurden persönlich mit Hilfe eines Interviews befragt, wobei als diagnostisches Instrument das M-CIDI mit seinen DSM-IV Algorithmen verwendet wurde. Die Ergebnisse aus der Basiserhebung ergaben, daß 1995 etwa 20% aller 14- bis 17jährigen - in der Mehrzahl wiederholt - Cannabis probiert hatten und 6% der Population einen regelmäßigen Gebrauch aufweisen. Die Einjahres-Inzidenz (= Auftreten neuer Fälle) für den Cannabisgebrauch der nun 15- bis 19jährigen betrug zum Zeitpunkt der Nachuntersuchung 20,1% für die Männer und 16,3% für die Frauen. Für den regelmäßigen Gebrauch wurden Inzidenzraen von 12% (Männer) und 8,4% (Frauen) ermittelt. Die Stabilität des Konsumverhaltens zwischen der Basis- und der Nachuntersuchung war relativ hoch un stieg mit höherem Initialkonsum an. Angesichts der hohen Gebrauchsrate von 32,4% bei den 15- bis 19jährigen bei der Nachuntersuchung ergab sich im Vergleich zu anderen psychotropen Substanzen eine relativ niedrige Prävalenz für Mißbrauch und Abhängigkeit (4%). Das Vorliegen einer Diagnose bei der Erstuntersuchung weist allerdings eine relativ hohe Stabilität über die Nachuntersuchungskette auf. / The paper examines the prevalence, incidence and stability patterns of cannabis use and dependence in a prospective epidemiological study of a random community sample of adolescents, aged 14 to 17 years (N=1395) at time 1. Assesments are based on personal interviews by trained clinical psychologists using the computerized DSM-IV lifetime and 12-month change version of the M-CIDI. Results indicate that in 1995 every fifth person aged 14 to 17 years had used cannabis at least once and 6% reported regular use. The 12-month incidence rates (i.e. proportion of the sample reporting first cannabis use in the last year) among subjects, 15 to 19 years of age at time 2, was high, with 20,1% of males and 16,3% of females reporting first use. The incidence of regular use was 12,0% (males) and 8,4% (females). The stability of consumption patterns from time 1 to time 2 was high. Increasing with higher initial consumption. Given the reexamined samples overall high cannabis consumption rates of 32,4%, the prevalence of clinically manifest DSM-IV abuse and dependence was low in comparison to other psychologic drugs (4%). However there was remarkable diagnostic stability over time in this age group of those with an initial diagnosis at time 1 receiving a diagnosis again at time 2.