Variations régionales du recours aux soins: quelques problèmes méthodologiques. [Regional variations in health services: various methodological problems].

Many studies show strong variation of health consumption between regions, suggesting that theses variations are related to the uncertainty of medical practice or to other factors related to health services or patients attitude. However the statistical interpretation of these variations is far from easy: apart from usual and specific information bias, there are statistical problems when observing incidence of events like health care consumption: it is in fact a rare event, which is observed within small population, and among regions with unequal number of person. Therefore, most of the variation reported might be well explained by a purely statistical phenomenon. This paper presents some aspects of this variability for three common indicators of variation, and suggest the use of ad hoc simulation to get statistical criteria.

Compositional data analysis of archaeological glass: problems and possible solutions

Presentation in CODAWORK'03, session 4: Applications to archeometry

On the way to solve lighting problems in underwater imaging

A major obstacle to processing images of the ocean floor comes from the absorption and scattering effects of the light in the aquatic environment. Due to the absorption of the natural light, underwater vehicles often require artificial light sources attached to them to provide the adequate illumination. Unfortunately, these flashlights tend to illuminate the scene in a nonuniform fashion, and, as the vehicle moves, induce shadows in the scene. For this reason, the first step towards application of standard computer vision techniques to underwater imaging requires dealing first with these lighting problems. This paper analyses and compares existing methodologies to deal with low-contrast, nonuniform illumination in underwater image sequences. The reviewed techniques include: (i) study of the illumination-reflectance model, (ii) local histogram equalization, (iii) homomorphic filtering, and, (iv) subtraction of the illumination field. Several experiments on real data have been conducted to compare the different approaches

Qualité des statistiques de causes de décès: problèmes actuels et perspectives. [Quality of statistics on causes of death: current problems and perspectives].

Statistics of causes of death remain an important source of epidemiological data for the evaluation of various medical and health problems. The improvement of analytical techniques and, above all, the transformation of demographic and morbid structures of populations have prompted researchers in the field to give more importance to the quality of death certificates. After describing the data collection system presently used in Switzerland, the paper discusses various indirect estimations of the quality of Swiss data and reviews the corresponding international literature.

An interdisciplinary HIV-adherence program combining motivational interviewing and electronic antiretroviral drug monitoring.

To ensure successful treatment, HIV patients must maintain a high degree of medication adherence over time. Since August 2004, patients who are (or are at risk of) experiencing problems with their HIV antiretroviral therapy (ART) have been referred by their physicians to an interdisciplinary HIV-adherence program. The program consists of a multifactorial intervention along with electronic drug monitoring (MEMS(TM)). The pharmacists organize individualized semi-structured motivational interviews based on cognitive, emotional, behavioral, and social issues. At the end of each session, the patient brings an adherence report to the physician. This enables the physician to use the adherence results to evaluate the treatment plan. The aim of this study was to retrospectively analyze this on-going interdisciplinary HIV-adherence program. All patients who were included between August 2004 and the end of April 2008 were analyzed. One hundred and four patients were included (59% women, median age 39 (31.0, 46.0) years, 42% black ethnicity). Eighty (77%) patients were ART-experienced patients and 59% had a protease inhibitor-based treatment. The retention rate was high (92%) in the program. Patient inclusion in this HIV-adherence program was determined by patient issues for naive patients and by nonadherence or suboptimal clinical outcomes for ART-experienced patients. The median time spent by a subject at the pharmacy was 35 (25.0, 48.0) minutes, half for the medication handling and half for the interview. The adherence results showed a persistence of 87% and an execution of 88%. Proportion of undetectable subjects increased during study. In conclusion, retention and persistence rates were high in this highly selected problematic population.

Oleoyl lysophosphatidic acid: a new mediator of emotional behavior in rats.

The role of lysophosphatidic acid (LPA) in the control of emotional behavior remains to be determined. We analyzed the effects of the central administration of 1-oleoyl-LPA (LPA 18∶1) in rats tested for food consumption and anxiety-like and depression-like behaviors. For this purpose, the elevated plus-maze, open field, Y maze, forced swimming and food intake tests were performed. In addition, c-Fos expression in the dorsal periaqueductal gray matter (DPAG) was also determined. The results revealed that the administration of LPA 18∶1 reduced the time in the open arms of the elevated plus-maze and induced hypolocomotion in the open field, suggesting an anxiogenic-like phenotype. Interestingly, these effects were present following LPA 18∶1 infusion under conditions of novelty but not under habituation conditions. In the forced swimming test, the administration of LPA 18∶1 dose-dependently increased depression-like behavior, as evaluated according to immobility time. LPA treatment induced no effects on feeding. However, the immunohistochemical analysis revealed that LPA 18∶1 increased c-Fos expression in the DPAG. The abundant expression of the LPA1 receptor, one of the main targets for LPA 18∶1, was detected in this brain area, which participates in the control of emotional behavior, using immunocytochemistry. These findings indicate that LPA is a relevant transmitter potentially involved in normal and pathological emotional responses, including anxiety and depression.

Mutigrid preconditioner for nonconforming discretization of elliptic problems with jump coefficients

In this paper, we present a multigrid preconditioner for solving the linear system arising from the piecewise linear nonconforming Crouzeix-Raviart discretization of second order elliptic problems with jump coe fficients. The preconditioner uses the standard conforming subspaces as coarse spaces. Numerical tests show both robustness with respect to the jump in the coe fficient and near-optimality with respect to the number of degrees of freedom.

Schwarz methods for a preconditioned WOPSIP method for elliptic problems

We construct and analyze non-overlapping Schwarz methods for a preconditioned weakly over-penalized symmetric interior penalty (WOPSIP) method for elliptic problems.

A note on discrete claims problems

In this note, we consider claims problems with indivisible goods. Specifically, by applying recursively the P-rights lower bound (Jiménez-Gómez and Marco-Gil (2008)), we ensure the fulfillment of Weak Order Preservation, considered by many authors as a minimal requirement of fairness. Moreover, we retrieve the Discrete Constrained Equal Losses and the Discrete Constrained Equal Awards rules (Herrero and Martíınez (2008)). Finally, by the recursive double imposition of a lower and an upper bound, we obtain the average between them. Keywords: Claims problems, Indivisibilities, Order Preservation, Constrained Egalitarian rules, Midpoint. JEL classification: C71, D63, D71.

Temperamental Dimension and Anxiety Problems in a Clinical Sample of Three- to Six-year old Children: A Study of Variables

In the last few years, many researchers have studied the presence of common dimensions of temperament in subjects with symptoms of anxiety. The aim of this study is to examine the association between temperamental dimensions (high negative affect and activity level) and anxiety problems in clinicalpreschool children. A total of 38 children, ages 3 to 6 years, from the Infant and Adolescent Mental Health Center of Girona and the Center of Diagnosis and Early Attention of Sabadell and Olot were evaluated by parents and psychologists. Their parents completed several screening scales and, subsequently, clinical child psychopathology professionals carried out diagnostic interviews with children from the sample who presented signs of anxiety. Findings showed that children with high levels of negative affect and low activity level have pronounced symptoms of anxiety. However, children with anxiety disorders do not present different temperament styles from their peers without these pathologies