Disclosure, banks CDS spreads and the European sovereign crisis

We investigate the impact of banks disclosure on the evolution of their CDS spreads during the European sovereign crisis. The disclosure of information helps investors in building expectations; disclosure may participate into the reduction of the information risk premium and may lead to a decrease of CDS spreads. We analyze the CDS spreads changes following the announcement of sovereign credit rating downgrades. We consider 16 dates in the period 2011-2013 and, for each one, we assess the cumulative abnormal CDS spread change (CASC). We build two disclosure indexes: one general and one specifically dedicated to sovereign exposure. We show that the bank exposure to sovereign risk has a positive impact on the CASC. Disclosure about sovereign exposure has a negative impact on CASC showing that information reduce risk premiums. However, the global disclosure increases the CASC; investors may disapprove the disclosure of too much abundant and broad information

Associations of social and material deprivation with tobacco, alcohol, and psychotropic drug use, and gender: a population-based study

International audienceBACKGROUND: The aim was to assess the relationships between social and material deprivation and the use of tobacco, excessive alcohol and psychotropic drugs by both sexes and in various age groups. Greater knowledge concerning these issues may help public health policy-makers design more effective means of preventing substance abuse. METHODS: The sample comprised 6,216 people aged > or 15 years randomly selected from the population in north-eastern France. Subjects completed a post-mailed questionnaire covering socio-demographic characteristics, occupation, employment, income, smoking habit, alcohol abuse and "psychotropic" drug intake (for headache, tiredness, nervousness, anxiety, insomnia). A deprivation score (D) was defined by the cumulative number of: low educational level, manual worker, unemployed, living alone, nationality other than western European, low income, and non-home-ownership. Data were analysed using adjusted odds ratios (ORa) computed with logistic models. RESULTS: Deprivation was common: 37.4% of respondents fell into category D = 1, 21.2% into D = 2, and 10.0% into D > or 3a re men than women reported tobacco use (30.2% vs. 21.9%) and alcohol abuse (12.5% vs. 3.3%), whereas psychotropic drug use was more common among women (23.8% vs. 41.0%). Increasing levels of deprivation were associated with a greater likelihood of tobacco use (ORa vs. D = 0: 1.16 in D = 1, 1.49 in D = 2, and 1.93 in D > or = 3), alcohol abuse (1.19 in D = 1, 1.32 in D = 2, and 1.80 in D > or = 3) and frequent psychotropic drug intake (1.26 in D = 1, 1.51 in D = 2, and 1.91 in D > or = 3). These patterns were observed in working/other non-retired men and women (except for alcohol abuse in women). Among retired people, deprivation was associated with tobacco and psychotropic drug use only in men. CONCLUSION: Preventive measures should be designed to improve work conditions, reduce deprivation, and help deprived populations to be more aware of risk and to find remedial measures

Vlasov moment flows and geodesics on the Jacobi group

By using the moment algebra of the Vlasov kinetic equation, we characterize the integrable Bloch-Iserles system on symmetric matrices (arXiv:math-ph/0512093) as a geodesic flow on the Jacobi group. We analyze the corresponding Lie-Poisson structure by presenting a momentum map, which both untangles the bracket structure and produces particle-type solutions that are inherited from the Vlasov-like interpretation. Moreover, we show how the Vlasov moments associated to Bloch-Iserles dynamics correspond to particular subgroup inclusions into a group central extension (first discovered in arXiv:math/0410100), which in turn underlies Vlasov kinetic theory. In the most general case of Bloch-Iserles dynamics, a generalization of the Jacobi group also emerges naturally.Comment: 45 page

Contributions of experiment designs in photodynamic therapy: photosensitizer design, treatment analysis and optimization.

Abstract published in Photodiagnosis and Photodynamic Therapy, 8(2):137, 2011International audienceIntroduction One of the difficulties in the development of the photodynamic therapy (PDT) is inherent to the multidisciplinary feature of this treatment gathering mainly clinicians, physicists, biologists, and chemists. Another issue is the great number of biophysical and biochemical parameters involved in the design of new photosensitizers as well as in the in vivo application of this treatment. We present a global development approach based on the methodology and tools of experimental design. Three study cases are developed to assess to potential relevance of such an empirical model-based approach for the development of PDT. Methods & Results In a first study, an in vitro screening experimental design was carried out. The addressed question dealt with the determination of influent factors on the phototoxicity of a new photosensitizer based on quantum dots. Five factors were examined: the nature of quantum dots, the excitation light wavelength, the incubation time with cells, the photoactivable compound concentration and the fluence level. Relevance of each factor was finally estimated and compared to identify the significant parameters. In comparison with a typical factorial design, the total number of experiments (42 trials) was divided by 5. In a second study, an in vivo factorial experimental design was applied to detect potential synergic effects between four therapeutic factors: the phenotype of the cancer cell line, the food type, the nature of photosensitizer and the post-injection time, on the in vivo selectivity (cancer/normal tissue) of the tested photosensitizers. Results particularly pointed out the presence of a statistically significant synergic effect between these four factors and provided the optimal modalities to maximize the response in term of tumor-to-normal tissue ratio. In a third study, a Doehlert experimental design associated with a response surface model was used to determine the in vivo PDT modalities (photosensitizer concentration, irradiance and fluence) to both minimize the post-treatment growth rate of the tumor and maximize its growth delay. Only 13 experimental conditions were tested and the relevance of the optimized condition was corroborated by in vivo validation experiments. Conclusion These studies have confirmed the applicability and attractive contributions of experimental design techniques in the development and determination of optimal modalities of new photosensitizers in PDT. Their main advantages are to a priori organize experiments according to specific questions while minimizing the experimental cost and controlling as much as possible the experimental uncertainty

Prevalence of impairments, disabilities, handicaps and quality of life in the general population: a review of recent literature

International audienc

Health-related quality of life in French adolescents and adults: norms for the DUKE Health Profile

<p>Abstract</p> <p>Background</p> <p>The continual monitoring of population health-related quality of life (HRQoL) with validated instruments helps public health agencies assess, protect, and promote population health. This study aimed to determine norms for the French adolescent and adult general population for the Duke Health Profile (DUKE) questionnaire in a large representative community sample.</p> <p>Methods</p> <p>We randomly selected 17,733 French people aged 12 to 75 years old in 2 steps, by households and individuals, from the National Health Barometer 2005, a periodic population study by the French National Institute for Prevention and Health Education. Quality of life and other data were collected by computer-assisted telephone interview.</p> <p>Results</p> <p>Normative data for the French population were analyzed by age, gender and self-reported chronic disease. Globally, function scores (best HRQoL=100) for physical, mental, social, and general health, as well as perceived health and self-esteem, were 72.3 (SEM 0.2), 74.6 (0.2), 66.8 (0.1), 71.3 (0.1), 71.3 (0.3), 76.5 (0.1), respectively. Dysfunction scores (worst HRQoL=100) for anxiety, depression, pain and disability domains were 30.9 (0.1), 27.6 (0.2), 34.3 (0.3), 3.1 (0.1), respectively.</p> <p>Conclusion</p> <p>The French norms for adolescents and adults for the DUKE could be used as a reference for other studies assessing HRQoL, for specific illnesses, in France and for international comparisons.</p

Methodological issues regarding power of classical test theory (CTT) and item response theory (IRT)-based approaches for the comparison of patient-reported outcomes in two groups of patients - a simulation study

<p>Abstract</p> <p>Background</p> <p>Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statistical properties of CTT and IRT, regarding power and corresponding effect sizes, were compared.</p> <p>Methods</p> <p>Two-group cross-sectional studies were simulated for the comparison of PRO data using IRT or CTT-based analysis. For IRT, different scenarios were investigated according to whether items or person parameters were assumed to be known, to a certain extent for item parameters, from good to poor precision, or unknown and therefore had to be estimated. The powers obtained with IRT or CTT were compared and parameters having the strongest impact on them were identified.</p> <p>Results</p> <p>When person parameters were assumed to be unknown and items parameters to be either known or not, the power achieved using IRT or CTT were similar and always lower than the expected power using the well-known sample size formula for normally distributed endpoints. The number of items had a substantial impact on power for both methods.</p> <p>Conclusion</p> <p>Without any missing data, IRT and CTT seem to provide comparable power. The classical sample size formula for CTT seems to be adequate under some conditions but is not appropriate for IRT. In IRT, it seems important to take account of the number of items to obtain an accurate formula.</p

Quantum dots in axillary lymph node mapping: Biodistribution study in healthy mice

<p>Abstract</p> <p>Background</p> <p>Breast cancer is the first cause of cancer death among women and its incidence doubled in the last two decades. Several approaches for the treatment of these cancers have been developed. The axillary lymph node dissection (ALND) leads to numerous morbidity complications and is now advantageously replaced by the dissection and the biopsy of the sentinel lymph node. Although this approach has strong advantages, it has its own limitations which are manipulation of radioactive products and possible anaphylactic reactions to the dye. As recently proposed, these limitations could in principle be by-passed if semiconductor nanoparticles (quantum dots or QDs) were used as fluorescent contrast agents for the <it>in vivo </it>imaging of SLN. QDs are fluorescent nanoparticles with unique optical properties like strong resistance to photobleaching, size dependent emission wavelength, large molar extinction coefficient, and good quantum yield.</p> <p>Methods</p> <p>CdSe/ZnS core/shell QDs emitting around 655 nm were used in our studies. 20 μL of 1 μM (20 pmol) QDs solution were injected subcutaneously in the anterior paw of healthy nude mice and the axillary lymph node (ALN) was identified visually after injection of a blue dye. <it>In vivo </it>fluorescence spectroscopy was performed on ALN before the mice were sacrificed at 5, 15, 30, 60 min and 24 h after QDs injection. ALN and all other organs were removed, cryosectioned and observed in fluorescence microscopy. The organs were then chemically made soluble to extract QDs. Plasmatic, urinary and fecal fluorescence levels were measured.</p> <p>Results</p> <p>QDs were detected in ALN as soon as 5 min and up to 24 h after the injection. The maximum amount of QDs in the ALN was detected 60 min after the injection and corresponds to 2.42% of the injected dose. Most of the injected QDs remained at the injection site. No QDs were detected in other tissues, plasma, urine and feces.</p> <p>Conclusion</p> <p>Effective and rapid (few minutes) detection of sentinel lymph node using fluorescent imaging of quantum dots was demonstrated. This work was done using very low doses of injected QDs and the detection was done using a minimally invasive method.</p