Spatial prediction of monthly wind speeds in complex terrain with adaptive general regression neural networks

This paper presents the general regression neural networks (GRNN) as a nonlinear regression method for the interpolation of monthly wind speeds in complex Alpine orography. GRNN is trained using data coming from Swiss meteorological networks to learn the statistical relationship between topographic features and wind speed. The terrain convexity, slope and exposure are considered by extracting features from the digital elevation model at different spatial scales using specialised convolution filters. A database of gridded monthly wind speeds is then constructed by applying GRNN in prediction mode during the period 1968-2008. This study demonstrates that using topographic features as inputs in GRNN significantly reduces cross-validation errors with respect to low-dimensional models integrating only geographical coordinates and terrain height for the interpolation of wind speed. The spatial predictability of wind speed is found to be lower in summer than in winter due to more complex and weaker wind-topography relationships. The relevance of these relationships is studied using an adaptive version of the GRNN algorithm which allows to select the useful terrain features by eliminating the noisy ones. This research provides a framework for extending the low-dimensional interpolation models to high-dimensional spaces by integrating additional features accounting for the topographic conditions at multiple spatial scales. Copyright (c) 2012 Royal Meteorological Society.

Stress ulcer prophylaxis in non-critically ill patients: a prospective evaluation of current practice in a general surgery department.

RATIONALE, AIMS AND OBJECTIVES: There is little evidence regarding the benefit of stress ulcer prophylaxis (SUP) outside a critical care setting. Overprescription of SUP is not devoid of risks. This prospective study aimed to evaluate the use of proton pump inhibitors (PPIs) for SUP in a general surgery department. METHOD: Data collection was performed prospectively during an 8-week period on patients hospitalized in a general surgery department (58 beds) by pharmacists. Patients with a PPI prescription for the treatment of ulcers, gastro-oesophageal reflux disease, oesophagitis or epigastric pain were excluded. Patients admitted twice during the study period were not reincluded. The American Society of Health-System Pharmacists guidelines on SUP were used to assess the appropriateness of de novo PPI prescriptions. RESULTS: Among 255 patients in the study, 138 (54%) received a prophylaxis with PPI, of which 86 (62%) were de novo PPI prescriptions. A total of 129 patients (94%) received esomeprazole (according to the hospital drug policy). The most frequent dosage was at 40 mg once daily. Use of PPI for SUP was evaluated in 67 patients. A total of 53 patients (79%) had no risk factors for SUP. Twelve and two patients had one or two risk factors, respectively. At discharge, PPI prophylaxis was continued in 33% of patients with a de novo PPI prescription. CONCLUSIONS: This study highlights the overuse of PPIs in non-intensive care unit patients and the inappropriate continuation of PPI prescriptions at discharge. Treatment recommendations for SUP are needed to restrict PPI use for justified indications.

La dépression majeure en hôpital général: adaptation et mise en oeuvre de recommandations pour la pratique clinique [Major depression in the general hospital: adaptation and implementation of guidelines]

Major depression IMD) is highly prevalent in the general hospital and adds a considerable burden to affected patients, but remains under detected and under treated. In an attempt to improve this situation, existing guidelines on MD were retrieved, systematically evaluated with the instrument AGREE (Appraisal of guidelines for research and evaluation), and adapted to the needs of the general hospital. These guidelines were made available on intranet, and actively implemented in two wards, where their impact on clinical practice was evaluated.

Effects of particulate matters on inflammatory markers in the general adult population

Summary: Particulate air pollution is associated with increased cardiovascular risk. The induction of systemic inflammation following particle inhalation represents a plausible mechanistic pathway. The purpose of this study was to assess the associations of short-term exposure to ambient particulate matters of aerodynamic diameter less than 10 μm (PM10) with circulating inflammatory markers in 6183 adults in Lausanne, Switzerland. The results show that short-term exposure to PM10 was associated with higher levels of circulating IL-6 and TNF-α. The positive association of PM10 with markers of systemic inflammation materializes the link between air pollution and cardiovascular risk. Background: Variations in short-term exposure to particulate matters (PM) have been repeatedly associated with daily all-cause mortality. Particle-induced inflammation has been postulated to be one of the important mechanisms for increased cardiovascular risk. Experimental in-vitro, in-vivo and controlled human studies suggest that interleukin 6 (IL-6) and tumor-necrosis-factor alpha (TNF-α) could represent key mediators of the inflammatory response to PM. The associations of short-term exposure to ambient PM with circulating inflammatory markers have been inconsistent in studies including specific subgroups so far. The epidemiological evidence linking short-term exposure to ambient PM and systemic inflammation in the general population is scarce. So far, large-scale population-based studies have not explored important inflammatory markers such as IL-6, IL-1β or TNF-α. We therefore analyzed the associations between short-term exposure to ambient PM10 and circulating levels of high-sensitive CRP (hs-CRP), IL-6, IL-1β and TNF-α in the population-based CoLaus study. Objectives: To assess the associations of short-term exposure to ambient particulate matters of aerodynamic diameter less than 10 μm (PM10) with circulating inflammatory markers, including hs-CRP, IL-6, IL-1β and TNF-α, in adults aged 35 to 75 years from the general population. Methodology: All study subjects were participants to the CoLaus study (www.colaus.ch) and the baseline examination was carried out from 2003 to 2006. Overall, 6184 participants were included. For the present analysis, 6183 participants had data on at least one of the four measured circulating inflammatory markers. The monitoring data was obtained from the website of Swiss National Air Pollution Monitoring Network (NABEL). We analyzed data on PM10 as well as outside air temperature, pressure and humidity. Hourly concentrations of PM10 were collected from 1 January 2003 to 31 December 2006. Robust linear regression (PROC ROBUSTREG) was used to evaluate the relationship between cytokine inflammatory and PM10. We adjusted all analyses for age, sex, body mass index, smoking status, alcohol consumption, diabetes status, hypertension status, education levels, zip code, and statin intake. All data were adjusted for the effects of weather by including temperature, barometric pressure, and season as covariates in the adjusted models. We performed simple and multiple logistic regression analyses. Descriptive statistical analysis used the Wilcoxon rank sum test (for medians). All data analyses were performed using SAS software (version 9.2; SAS Institute Inc., Cary, NC, USA), and a two-sided significance level of 5% was used. Results: PM10 levels averaged over 24 hours were significantly and positively associated with continuous IL-6 and TNF-α levels, in the whole study population both in unadjusted and adjusted analyses. For each cytokine, there was a similar seasonal pattern, with wider confidence intervals in summer than during the other seasons, which might partly be due to the smaller number of participants examined in summer. The associations of PM10 with IL-6 and TNF-α were also found after having dichotomized these cytokines into high versus low levels, which suggests that the associations of PM10 with the continuous cytokine levels are very robust to any distributional assumption and to potential outlier values. In contrast with what we observed for continuous IL-1β levels, high PM10 levels were significantly associated with high IL-1β. PM10 was significantly associated with IL-6 and TNF-α in men, but with TNF-α only in women. However, there was no significant statistical interaction between PM10 and sex. For IL-6 and TNF-α, the associations tended to be stronger in younger people, with a significant interaction between PM10 and age groups for IL-6. PM10 was significantly associated with IL-6 and TNF-α in the healthy group and also in the "non-healthy" group, although the statistical interaction between healthy status and PM10 was not significant. Conclusion: In summary, we found significant independent positive associations of short-term exposure to PM10 with circulating levels of IL-6 and TNF-α in the adult population of Lausanne. Our findings strongly support the idea that short-term exposure to PM10 is sufficient to induce systemic inflammation on a broad scale in the general population. From a public health perspective, the reported association of elevated inflammatory cytokines with short-term exposure to PM10 in a city with relatively clean air such as Lausanne supports the importance of limiting urban air pollution levels.

Précarité et déterminants sociaux de la santé: quel(s) rôle(s) pour le médecin de premier recours [Deprivation and social determinants of health: any role for the general practitioner?]

Social deprivation also exists in an industrialised country like Switzerland where there are many different social economic levels; social inequalities have increased in the past years having a major impact on social economic determinants of health. Being aware of these determinants and systematically identifying them in patients has become crucial for the general practitioner in order to improve the way s/he delivers care and interacts with more vulnerable populations. Because the general practitioner is often in contact with people of different socioeconomic levels, s/he is a key witness of social inequalities in health. S/he therefore has a responsibility to document them, to promote health, to prevent disease and be an advocate for the disadvantages in order to influence these social determinants of health.

Atypical depression and alcohol misuse are related to the cardiovascular risk in the general population.

OBJECTIVE: The aims of the present study were to assess the associations between mood, anxiety and substance use disorders, including their subtypes, and the prevalence of cardiovascular risk factors (CVRFs). METHOD: Thorough physical investigations, biological measures and standardized interview techniques were used to assess 3716 subjects of an urban area, aged 35-66 years. RESULTS: Atypical depression was associated with increased prevalence of overweight, diabetes and the metabolic syndrome (OR = 1.5, 95% C.I. 1.1-2.0; OR = 2.0, 95% C.I. 1.1-3.5, OR = 1.6, 95% C.I. 1.0-2.4 respectively), whereas decreased prevalence of overweight was found in melancholic (OR = 0.7, 95% C.I. 0.6-0.9) and unspecified depression (OR = 0.8, 95% C.I. 0.7-1.0). Alcohol abuse was associated with diabetes (OR = 1.8, 95% C.I. 1.1-2.9) and dyslipidemia (OR = 1.3, 95% C.I. 1.0-1.8), alcohol dependence with dyslipidemia only (OR = 1.4, 95% C.I. 1.0-2.0). Almost all mental disorders were associated with a lifetime history of regular cigarette smoking, and atypical depression, alcohol misuse and drug dependence were associated with inactivity. CONCLUSION: To conclude results emphasize the need to subtype depression and to pay particular attention to the atypical subtype. Comorbid alcohol misuse may further increase the cardiovascular risk. Efforts to diminish smoking in subjects with mental disorders could be crucial measures to reduce their high incidence of cardiovascular disease.