High altitude journeys and flights are associated with the increased risk of flares in IBD patients

Background: There is increasing evidence that hypoxia induces inflammation in the gastrointestinal tract. The clinical impact of hypoxia in patients with inflammatory bowel disease (IBD) is so far poorly investigated. Aim: We wanted to evaluate if flights and journeys to regions >= 2000 meter above sea level are associated with the occurrence of flares in IBD patients in the following 4 weeks. Methods: A questionnaire was completed by inpatients and outpatients of the IBD clinics of three tertiary referral centers presenting with an IBD flare. Patients were inquired about their habits in the 4 weeks prior to the flare. Patients with flares were matched with an IBD group in remission during the observation period (according to age, gender, smoking habits, and medication). Results: A total of 103 IBD patients were included (43 Crohn's disease (CD), whereof 65% female, 60 ulcerative colitis, whereof 47% female, mean age 39.3 ± 14.6 years for CD and 43.1 ± 14.2 years for UC). Fifty-two patients with flares were matched to 51 patients without flare. Overall, IBD-patients with flares had significantly more frequently a flight and/or journey to regions >= 2000 meters above sea level in the observation period compared to the patients in remission (21/52 (40.4%) vs. 8/51 (15.7%), p = 0.005). There was a statistically significant correlation between the occurrence of a flare and a flight and/or journey to regions >= 2000 meters above sea level among CD patients with flares as compared to CD patients in remission (8/21 (38.1%) vs. 2/22 (9.1%), p = 0.024). A trend for more frequent flights and high-altitude journeys was observed in UC patients with flares (13/31 (41.9%) vs. 6/29 (20.7%), p = 0.077). Mean flight duration was 5.8 ± 4.3 hours. The groups were controlled for the following factors (always flare group cited first): age (39.6 ± 13.4 vs. 43.5 ± 14.6, p = 0.102), smoking (16/52 vs. 10/51, p = 0.120), regular sports activities (32/52 vs. 33/51, p = 0.739), treatment with antibiotics in the 4 weeks before flare (8/52 vs. 7/51, p = 0.811), NSAID intake (12/52 vs. 7/51, p = 0.221), frequency of chronic obstructive pulmonary disease (both groups 0) and oxygen therapy (both groups 0). Conclusion: IBD patients with a flare had significantly more frequent flights and/or high-altitude journeys within four weeks prior to the IBD flare compared to the group that was in remission. We conclude that flights and stays in high altitude are a risk factor for IBD flares.

Dynamic stackelberg game with risk-averse players: optimal risk-sharing under asymmetric information

The objective of this paper is to clarify the interactive nature of the leader-follower relationship when both players are endogenously risk-averse. The analysis is placed in the context of a dynamic closed-loop Stackelberg game with private information. The case of a risk-neutral leader, very often discussed in the literature, is only a borderline possibility in the present study. Each player in the game is characterized by a risk-averse type which is unknown to his opponent. The goal of the leader is to implement an optimal incentive compatible risk-sharing contract. The proposed approach provides a qualitative analysis of adaptive risk behavior profiles for asymmetrically informed players in the context of dynamic strategic interactions modelled as incentive Stackelberg games.

Nash equilibrium strategies in discrete-time finite-horizon dynamic games with risk-and effort-averse players

The objective of this paper is to re-examine the risk-and effort attitude in the context of strategic dynamic interactions stated as a discrete-time finite-horizon Nash game. The analysis is based on the assumption that players are endogenously risk-and effort-averse. Each player is characterized by distinct risk-and effort-aversion types that are unknown to his opponent. The goal of the game is the optimal risk-and effort-sharing between the players. It generally depends on the individual strategies adopted and, implicitly, on the the players' types or characteristics.

Prevalence of antibodies to Hepatitis C virus in populations at low and high risk for sexually transmited diseases in Rio de Janeiro

In order to investigate the sexual transmission of the Hepatitis C Virus (HCV), the prevalence of specific antibodies in populations at high and low risk for sexually transmitted diseases (STDs) was evaluated. The population at low risk for STDs was composed of persons who voluntarity donated blood at the Hospital Universitário Clementino Fraga Filho (HUCFF) between July and November, 1990 (n = 2494). The population at high risk for STDs was drawn from an ongoing study on the natural history of Human Immunodeficiency Virus (HIV) infection (n = 210, 187 with sexual risk factors for HIV infection). All samples were screened using a first generation ELISA. Repeat reactive samples were then tested in a second generation RIBA. For all ELISA positive samples, two sex and age-matched ELISA negative controls were selected. Data pertaining to the presence of antibodies to the Hepatitis B core antigen (anti-HBC antibodies) and to Treponema pallidum were abstracted from the medical records. The prevalence of RIBA 2 confirmed HCV infection among the blood donors was 2.08%, which is well above the reported prevalence in similar populations from developed western countries. Among the HIV infected homosexuals, the encountered prevalence was 7.96% (p < 0.0005). For the whole group with sexually acquired HIV infection, the prevalence was 8.02% (p < 0.000005). Anti-HBc antibodies were more frequently present in anti-HCV RIBA-2 confirmed positive blood donors than in controls (p < 0.001). 33.3% of the HCV-positive blood donors and 11.04% controls were found to be anti-HBc positive (p < 0.0005). As for the FTA-ABs, 17.6% HCV-positive donors and 4,9% controls were positive (p < 0.01). 5.9% samples from blood donors were both anti-HBc and FTA-ABS positive, whereas none of the controls reacted in both tests (p < 0.05). The association between HCV, Hepatitis B infection and syphilis in individuals at low risk for parenterally transmitted diseases suggests that sexual transmission contributes to the maintenance of the endemicity of HCV in the local population.

Prevalence and risk factors for gastro-esophageal reflux disease in the North-Eastern part of Bangladesh.

Despite a common disorder population-based data on gastro-esophageal reflux disease (GERD) in Bangladesh is lacking. This epidemiological study was designed to determine the prevalence of GERD and its association with lifestyle factors. This population-based cross-sectional study was done by door to door interview of randomly selected persons in both urban and rural areas of North Eastern part of Bangladesh by using a validated questionnaire. A cutoff point 3 was chosen as a valid and reliable scale to confirm GERD. Statistical analysis was done by SPSS-12 version and the level of significance was set at P < or = 0.05. A total of 2000 persons with an age range of 15 to 85 years were interviewed; 1000 subjects from urban area and 1000 from rural area. Among the study subjects 1064 were male and 936 were female. A total of 110 persons (5.5%) were found to have GERD symptoms and among them 47 were men and 67 were women. The monthly, weekly and daily prevalence of heart-burn and or acid regurgitation was 5.5%, 5.25% and 2.5% respectively. Female sex, increased age and lower level of education were significantly associated with GERD symptoms. Prevalence was found more among city dwellers (approximately 6.0% versus 4.8%), married (6.23%, n = 86), widowed/widowers (16.83%, n = 17) and day labourer (8.78%). Level of education inversely influenced the prevalence. No significant association of GERD was found with body mass index (BMI) and smoking. Prevalence of GERD in North-Eastern part of Bangladesh was lower than that of western world. Prevalence was found higher in urban population, women, married, widowed/widowers and in poor an dilliterate persons. BMI and smoking had no significant association with GERD.

Les symbioses agro-industrielles en Afrique de l'Ouest : évaluation du potentiel d'une nouvelle stratégie pour un développement durable

RésuméCette thèse traite de l'utilisation des concepts de Symbiose Industrielle dans les pays en développement et étudie le potentiel de cette stratégie pour stimuler un développement régional durable dans les zones rurales d'Afrique de l'Ouest. En particulier, lorsqu'une Symbiose Industrielle est instaurée entre une usine et sa population alentour, des outils d'évaluation sont nécessaires pour garantir que le projet permette d'atteindre un réel développement durable. Les outils existants, développés dans les pays industrialisés, ne sont cependant pas complètement adaptés pour l'évaluation de projets dans les pays en développement. En effet, les outils sont porteurs d'hypothèses implicites propres au contexte socio-économique dans lequel ils ont été conçus.L'objectif de cette thèse est de développer un cadre méthodologique pour l'évaluation de la durabilité de projets de Symbiose Industrielle dans les pays en développement.Pour ce faire, je m'appuie sur une étude de cas de la mise en place d'une Symbiose Industrielle au nord du Nigéria, à laquelle j'ai participé en tant qu'observatrice dès 2007. AshakaCem, une usine productrice de ciment du groupe Lafarge, doit faire face à de nombreuses tensions avec la population rurale alentour. L'entreprise a donc décidé d'adopter une nouvelle méthode inspirée des concepts de Symbiose Industrielle. Le projet consiste à remplacer jusqu'à 10% du carburant fossile utilisé pour la cuisson de la matière crue (calcaire et additifs) par de la biomasse produite par les paysans locaux. Pour ne pas compromettre la fragile sécurité alimentaire régionale, des techniques de lutte contre l'érosion et de fertilisation naturelle des sols sont enseignées aux paysans, qui peuvent ainsi utiliser la culture de biomasse pour améliorer leurs cultures vivrières. A travers cette Symbiose Industrielle, l'entreprise poursuit des objectifs sociaux (poser les bases nécessaires à un développement régional), mais également environnementaux (réduire ses émissions de CO2 globales) et économiques (réduire ses coûts énergétiques). Elle s'ancre ainsi dans une perspective de développement durable qui est conditionnelle à la réalisation du projet.A travers l'observation de cette Symbiose et par la connaissance des outils existants je constate qu'une évaluation de la durabilité de projets dans les pays en développement nécessite l'utilisation de critères d'évaluation propres à chaque projet. En effet, dans ce contexte, l'emploi de critères génériques apporte une évaluation trop éloignée des besoins et de la réalité locale. C'est pourquoi, en m'inspirant des outils internationalement reconnus comme l'Analyse du Cycle de Vie ou la Global Reporting Initiative, je définis dans cette thèse un cadre méthodologique qui peut, lui, être identique pour tous les projets. Cette stratégie suit six étapes, qui se réalisent de manière itérative pour permettre une auto¬amélioration de la méthodologie d'évaluation et du projet lui-même. Au cours de ces étapes, les besoins et objectifs en termes sociaux, économiques et environnementaux des différents acteurs sont déterminés, puis regroupés, hiérarchisés et formulés sous forme de critères à évaluer. Des indicateurs quantitatifs ou qualitatifs sont ensuite définis pour chacun de ces critères. Une des spécificités de cette stratégie est de définir une échelle d'évaluation en cinq graduations, identique pour chaque indicateur, témoignant d'un objectif totalement atteint (++) ou pas du tout atteint (--).L'application de ce cadre méthodologique à la Symbiose nigériane a permis de déterminer quatre critères économiques, quatre critères socio-économiques et six critères environnementaux à évaluer. Pour les caractériser, 22 indicateurs ont été définis. L'évaluation de ces indicateurs a permis de montrer que le projet élaboré atteint les objectifs de durabilité fixés pour la majorité des critères. Quatre indicateurs ont un résultat neutre (0), et un cinquième montre qu'un critère n'est pas atteint (--). Ces résultats s'expliquent par le fait que le projet n'en est encore qu'à sa phase pilote et n'a donc pas encore atteint la taille et la diffusion optimales. Un suivi sur plusieurs années permettra de garantir que ces manques seront comblés.Le cadre méthodologique que j'ai développé dans cette thèse est un outil d'évaluation participatif qui pourra être utilisé dans un contexte plus large que celui des pays en développement. Son caractère générique en fait un très bon outil pour la définition de critères et indicateurs de suivi de projet en terme de développement durable.SummaryThis thesis examines the use of industrial symbiosis in developing countries and studies its potential to stimulate sustainable regional development in rural areas across Western Africa. In particular, when industrial symbiosis is instituted between a factory and the surrounding population, evaluation tools are required to ensure the project achieves truly sustainable development. Existing tools developed in industrialized countries are not entirely suited to assessing projects in developing countries. Indeed, the implicit hypotheses behind such tools reflect the socioeconomic context in which they were designed. The goal of this thesis is to develop a methodological framework for evaluating the sustainability of industrial symbiosis projects in developing countries.To accomplish this, I followed a case study about the implementation of industrial symbiosis in northern Nigeria by participating as an observer since 2007. AshakaCem, a cement works of Lafarge group, must confront many issues associated with violence committed by the local rural population. Thus, the company decided to adopt a new approach inspired by the concepts of industrial symbiosis.The project involves replacing up to 10% of the fossil fuel used to heat limestone with biomass produced by local farmers. To avoid jeopardizing the fragile security of regional food supplies, farmers are taught ways to combat erosion and naturally fertilize the soil. They can then use biomass cultivation to improve their subsistence crops. Through this industrial symbiosis, AshakaCem follows social objectives (to lay the necessary foundations for regional development), but also environmental ones (to reduce its overall CO2 emissions) and economical ones (to reduce its energy costs). The company is firmly rooted in a view of sustainable development that is conditional upon the project's execution.By observing this symbiosis and by being familiar with existing tools, I note that assessing the sustainability of projects in developing countries requires using evaluation criteria that are specific to each project. Indeed, using generic criteria results in an assessment that is too far removed from what is needed and from the local reality. Thus, by drawing inspiration from such internationally known tools as Life Cycle Analysis and the Global Reporting Initiative, I define a generic methodological framework for the participative establishment of an evaluation methodology specific to each project.The strategy follows six phases that are fulfilled iteratively so as to improve the evaluation methodology and the project itself as it moves forward. During these phases, the social, economic, and environmental needs and objectives of the stakeholders are identified, grouped, ranked, and expressed as criteria for evaluation. Quantitative or qualitative indicators are then defined for each of these criteria. One of the characteristics of this strategy is to define a five-point evaluation scale, the same for each indicator, to reflect a goal that was completely reached (++) or not reached at all (--).Applying the methodological framework to the Nigerian symbiosis yielded four economic criteria, four socioeconomic criteria, and six environmental criteria to assess. A total of 22 indicators were defined to characterize the criteria. Evaluating these indicators made it possible to show that the project meets the sustainability goals set for the majority of criteria. Four indicators had a neutral result (0); a fifth showed that one criterion had not been met (--). These results can be explained by the fact that the project is still only in its pilot phase and, therefore, still has not reached its optimum size and scope. Following up over several years will make it possible to ensure these gaps will be filled.The methodological framework presented in this thesis is a highly effective tool that can be used in a broader context than developing countries. Its generic nature makes it a very good tool for defining criteria and follow-up indicators for sustainable development.

Impact of clinical practice guidelines on priorisation for intensive care beds allocation in high-risk acute coronary syndrome patients: does age play a role?

QUESTION UNDER STUDY: To assess which high-risk acute coronary syndrome (ACS) patient characteristics played a role in prioritising access to intensive care unit (ICU), and whether introducing clinical practice guidelines (CPG) explicitly stating ICU admission criteria altered this practice. PATIENTS AND METHODS: All consecutive patients with ACS admitted to our medical emergency centre over 3 months before and after CPG implementation were prospectively assessed. The impact of demographic and clinical characteristics (age, gender, cardiovascular risk factors, and clinical parameters upon admission) on ICU hospitalisation of high-risk patients (defined as retrosternal pain of prolonged duration with ECG changes and/or positive troponin blood level) was studied by logistic regression. RESULTS: Before and after CPG implementation, 328 and 364 patients, respectively, were assessed for suspicion of ACS. Before CPG implementation, 36 of the 81 high-risk patients (44.4%) were admitted to ICU. After CPG implementation, 35 of the 90 high-risk patients (38.9%) were admitted to ICU. Male patients were more frequently admitted to ICU before CPG implementation (OR=7.45, 95% CI 2.10-26.44), but not after (OR=0.73, 95% CI 0.20-2.66). Age played a significant role in both periods (OR=1.57, 95% CI 1.24-1.99), both young and advanced ages significantly reducing ICU admission, but to a lesser extent after CPG implementation. CONCLUSION: Prioritisation of access to ICU for high-risk ACS patients was age-dependent, but focused on the cardiovascular risk factor profile. CPG implementation explicitly stating ICU admission criteria decreased discrimination against women, but other factors are likely to play a role in bed allocation.

Rockfall hazard and risk assessments along roads at a regional scale: Example in Swiss Alps

Unlike fragmental rockfall runout assessments, there are only few robust methods to quantify rock-mass-failure susceptibilities at regional scale. A detailed slope angle analysis of recent Digital Elevation Models (DEM) can be used to detect potential rockfall source areas, thanks to the Slope Angle Distribution procedure. However, this method does not provide any information on block-release frequencies inside identified areas. The present paper adds to the Slope Angle Distribution of cliffs unit its normalized cumulative distribution function. This improvement is assimilated to a quantitative weighting of slope angles, introducing rock-mass-failure susceptibilities inside rockfall source areas previously detected. Then rockfall runout assessment is performed using the GIS- and process-based software Flow-R, providing relative frequencies for runout. Thus, taking into consideration both susceptibility results, this approach can be used to establish, after calibration, hazard and risk maps at regional scale. As an example, a risk analysis of vehicle traffic exposed to rockfalls is performed along the main roads of the Swiss alpine valley of Bagnes.

Focus sur l'échantillonnage de la poussière sédimentée avec des lingettes électrostatiques dans l'évaluation de l'exposition aux micro-organismes

L'exposition aux microorganismes en environnement intérieur a été associée à la survenue de troubles respiratoires et symptômes allergiques chez les personnes exposées (1). Investiguer la relation dose-réponse entre exposition et effets sur la santé est essentiel dans la prévention de l'apparition de ces symptômes. Cependant, la mesure de l'exposition par prélèvement actif des bioaérosols est coûteuse et contraignante à mettre en place sur un grand nombre de sites en parallèle. C'est pourquoi les méthodes de prélèvement passif de la poussière sédimentée sont de plus en plus souvent envisagées pour répondre à cette problématique. Pour valider l'efficacité d'évaluation de l'exposition par ces dernières méthodes, il est nécessaire de montrer que la poussière sédimentée est bien représentative de la poussière inhalable. Le premier article cité dans cette note se propose de répondre à ce point. De plus, il faut identifier les facteurs qui peuvent influencer les concentrations en micro-organismes dans ces poussières sédimentées. Le deuxième article choisi dans cette note répond à ce dernier aspect.

Clinical follow-up of women infected with human papillomavirus-16, either alone or with other human papillomavirus types: identification of different risk groups.

OBJECTIVES: Evaluation of the clinical impact of multiple infections of the cervix by human papillomavirus, including human papillomavirus-16, compared with single human papillomavirus-16 infection. STUDY DESIGN: One hundred sixty-nine women were classified in 3 categories depending on their human papillomavirus profile: human papillomavirus-16 only, human papillomavirus-16 and low-risk type(s), and human papillomavirus-16 and other high-risk type(s). Cervical brush samples were analyzed for human papillomavirus DNA by polymerase chain reaction and reverse line blot hybridization. All women were evaluated with colposcopy during 24 months or more. Management was according to the Bethesda recommendations. RESULTS: Women infected with human papillomavirus-16 and other high-risk human papillomavirus type(s) presented more progression or no change in the grade of dysplasia, compared with women of the other groups (relative risk [RR], 1.39; 95% confidence interval [CI], 1.07-1.82; P = .02 at 6 months; RR, 2.10; 95% CI, 1.46-3.02; P < .001 at 12 months; RR, 1.82; 95% CI, 1.21-2.72; P = .004 at 24 months). CONCLUSION: Coinfection of women with human papillomavirus-16 and other high-risk human papillomavirus type(s) increases the risk of unfavorable evolution.

Differences in self-reported prevalence and management of cardiovascular risk factors in Switzerland, 2007

Purpose: To assess the prevalence of four self-reported cardiovascular risk factors (CV RFs: smoking, hypertension, dyslipidaemia and diabetes) and their reported management in seven Swiss regions (Léman, MiUelland, Zurich, North-West Switzerland, Oriental Switzerland, Central Switzerland and Tessin). Methods: National health interview survey conducted in 2007 in a representative sample of the Swiss population (17,879 subjects). Age-adjusted data on prevalence of self-reported CV RFs, treatment among participants reporting a RF, control of RFs among treated participants and CV RF screening in the last 12 months levels were computed after weighting. Results: The prevalence of hypertension was highest in North-West Switzerland (27.3%) and lowest in Central Switzerland (21.0%, p<0.001). Antihypertensive treatment was highest in Léman region (62.7%) and lowest in Oriental Switzerland (55.2%, p<0.001). Screening was higher in Tessin (89.3%) and lowest in Léman region (81.8%, p<0.001). Prevalence of dyslipidaemia was highest in Tessin and Léman region (20.7% and 20.1 %, respectively) and lowest in Oriental Switzerland (14.5%, p<0.001). Lipid-Iowering treatment was highest in Tessin and Léman region (44.3% each) and lowest in Central Switzerland (30.7%, p<0.001). Dyslipidaemia screening was highest in Tessin (76.6%) and lowest in Central Switzerland (58.6%, p<0.001). Prevalence of diabetes was highest in North-West Switzerland (5.4%) and lowest in Central Switzerland (3.3%, p<0.05). Diabetes screening was highest in Tessin (78.1%) and lowest in Oriental Switzerland (64.0%, p<0.001). Conversely, no between-region differences were found for hypertension or dyslipidaemia control (see table). Conclusion: there are significant differences between the Swiss regions in self-reported prevalence and management of CV RFs. Screening is beUer in Tessin than in the other regions.