Multimodel inference and multimodel averaging in empirical modeling of occupational exposure levels.

Empirical modeling of exposure levels has been popular for identifying exposure determinants in occupational hygiene. Traditional data-driven methods used to choose a model on which to base inferences have typically not accounted for the uncertainty linked to the process of selecting the final model. Several new approaches propose making statistical inferences from a set of plausible models rather than from a single model regarded as 'best'. This paper introduces the multimodel averaging approach described in the monograph by Burnham and Anderson. In their approach, a set of plausible models are defined a priori by taking into account the sample size and previous knowledge of variables influent on exposure levels. The Akaike information criterion is then calculated to evaluate the relative support of the data for each model, expressed as Akaike weight, to be interpreted as the probability of the model being the best approximating model given the model set. The model weights can then be used to rank models, quantify the evidence favoring one over another, perform multimodel prediction, estimate the relative influence of the potential predictors and estimate multimodel-averaged effects of determinants. The whole approach is illustrated with the analysis of a data set of 1500 volatile organic compound exposure levels collected by the Institute for work and health (Lausanne, Switzerland) over 20 years, each concentration having been divided by the relevant Swiss occupational exposure limit and log-transformed before analysis. Multimodel inference represents a promising procedure for modeling exposure levels that incorporates the notion that several models can be supported by the data and permits to evaluate to a certain extent model selection uncertainty, which is seldom mentioned in current practice.

Patients' preferences on information and involvement in decision-making for gastrointestinal surgery

Objective: The relationship between physicians and patients has undergone¦important changes, and the current emancipation of patients has led to¦a real partnership in medical decision-making. This study aimed to assess¦patients' preferences on different aspects of decision-making during treatment¦and potential complications, as well as the amount and type of preoperative¦information before visceral surgery.¦Methods: Prospective non-randomized study based on a questionnaire given¦to 253 consecutive patients scheduled for elective GI surgery.¦Results: Concerning surgical complications or treatment in the intensive care¦unit, 64% of patients wished to take actively part in any medical decisions.¦The respective figures for cardiac resuscitation and treatment limitations were¦89% and 60%. About information, 73%, 77% and 47% of patients wish¦detailed information, information on a potential ICUhospitalization and cardiac¦resuscitation, respectively. Elderly and low-educated patients were significantly¦less interested in shared medical decision-making (p = 0·003 and 0·015) and in¦information receiving (p = 0·03 and 0·05). Similarly, involvement of the family¦in decision-making was significantly less important in elderly and male patients¦(p = 0·05 and 0·03 respectively). Neither the type of operation (minor or major)¦nor the severity of disease (malignancies vs. non-malignancies) was a significant¦factor for shared decision-making, information or family involvement.¦Conclusion: The vast majority of surgical patients clearly want to get adequate¦preoperative information about their disease and the planned treatment. They¦also consider it as crucial to be involved in any kind of decision-making for¦treatment and complications. The family's role is limited to support the treating¦physicians if the patient is unable to participate in taking decisions.

Influence of CRTC1 Polymorphisms on Body Mass Index and Fat Mass in Psychiatric Patients and the General Adult Population.

IMPORTANCE There is a high prevalence of obesity in psychiatric patients, possibly leading to metabolic complications and reducing life expectancy. The CREB-regulated transcription coactivator 1 (CRTC1) gene is involved in energy balance and obesity in animal models, but its role in human obesity is unknown. OBJECTIVE To determine whether polymorphisms within the CRTC1 gene are associated with adiposity markers in psychiatric patients and the general population. DESIGN, SETTING, AND PARTICIPANTS Retrospective and prospective data analysis and population-based samples at Lausanne and Geneva university hospitals in Switzerland and a private clinic in Lausanne, Switzerland. The effect of 3 CRTC1 polymorphisms on body mass index (BMI) and/or fat mass was investigated in a discovery cohort of psychiatric outpatients taking weight gain-inducing psychotropic drugs (sample 1, n = 152). The CRTC1 variant that was significantly associated with BMI and survived Bonferroni corrections for multiple comparison was then replicated in 2 independent psychiatric samples (sample 2, n = 174 and sample 3, n = 118) and 2 white population-based samples (sample 4, n = 5338 and sample 5, n = 123 865). INTERVENTION Noninterventional studies. MAIN OUTCOME AND MEASURE Difference in BMI and/or fat mass between CRTC1 genotype groups. RESULTS Among the CRTC1 variants tested in the first psychiatric sample, only rs3746266A>G was associated with BMI (Padjusted = .003). In the 3 psychiatric samples, carriers of the rs3746266 G allele had a lower BMI than noncarriers (AA genotype) (sample 1, P = .001; sample 2, P = .05; and sample 3, P = .0003). In the combined analysis, excluding patients taking other weight gain-inducing drugs, G allele carriers (n = 98) had a 1.81-kg/m2 lower BMI than noncarriers (n = 226; P < .0001). The strongest association was observed in women younger than 45 years, with a 3.87-kg/m2 lower BMI in G allele carriers (n = 25) compared with noncarriers (n = 48; P < .0001), explaining 9% of BMI variance. In the population-based samples, the T allele of rs6510997C>T (a proxy of the rs3746266 G allele; r2 = 0.7) was associated with lower BMI (sample 5, n = 123 865; P = .01) and fat mass (sample 4, n = 5338; P = .03). The strongest association with fat mass was observed in premenopausal women (n = 1192; P = .02). CONCLUSIONS AND RELEVANCE These findings suggest that CRTC1 contributes to the genetics of human obesity in psychiatric patients and the general population. Identification of high-risk subjects could contribute to a better individualization of the pharmacological treatment in psychiatry.

Length of hospital stay and postdischarge mortality in patients with pulmonary embolism: a statewide perspective

BACKGROUND: The optimal length of stay (LOS) for patients with pulmonary embolism (PE) is unknown. Although reducing LOS is likely to save costs, the effects on patient safety are unclear. We sought to identify patient and hospital factors associated with LOS and assess whether LOS was associated with postdischarge mortality. METHODS: We evaluated patients discharged with a primary diagnosis of PE from 186 acute care hospitals in Pennsylvania (January 2000 through November 2002). We used discrete survival models to examine the association between (1) patient and hospital factors and the time to discharge and (2) LOS and postdischarge mortality within 30 days of presentation, adjusting for patient and hospital factors. RESULTS: Among 15 531 patient discharges with PE, the median LOS was 6 days, and postdischarge mortality rate was 3.3%. In multivariate analysis, patients from Philadelphia were less likely to be discharged on a given day (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.73-0.93), as were black patients (OR, 0.88; 95% CI, 0.82-0.94).The odds of discharge decreased notably with greater patient severity of illness and in patients without private health insurance. Adjusted postdischarge mortality was significantly higher for patients with an LOS of 4 days or less (OR, 1.55; 95% CI, 1.21-2.00) relative to those with an LOS of 5 to 6 days. CONCLUSIONS: Several hospital and patient factors were independently associated with LOS. Patients with a very short LOS had greater postdischarge mortality relative to patients with a typical LOS, suggesting that physicians may inappropriately select patients with PE for early discharge who are at increased risk of complications

Application of detection probabilities to the design of amphibian monitoring programs in temporary ponds

Failure to detect a species in an area where it is present is a major source of error in biological surveys. We assessed whether it is possible to optimize single-visit biological monitoring surveys of highly dynamic freshwater ecosystems by framing them a priori within a particular period of time. Alternatively, we also searched for the optimal number of visits and when they should be conducted. We developed single-species occupancy models to estimate the monthly probability of detection of pond-breeding amphibians during a four-year monitoring program. Our results revealed that detection probability was species-specific and changed among sampling visits within a breeding season and also among breeding seasons. Thereby, the optimization of biological surveys with minimal survey effort (a single visit) is not feasible as it proves impossible to select a priori an adequate sampling period that remains robust across years. Alternatively, a two-survey combination at the beginning of the sampling season yielded optimal results and constituted an acceptable compromise between sampling efficacy and survey effort. Our study provides evidence of the variability and uncertainty that likely affects the efficacy of monitoring surveys, highlighting the need of repeated sampling in both ecological studies and conservation management.

Diet-induced thermogenesis in chronic obstructive pulmonary disease.

Increased resting energy expenditure and malnutrition are frequently observed in patients with COPD. The aim of this study was to examine the possible contribution of an increased diet-induced thermogenesis (DIT) to weight loss. Eleven patients with COPD in stable clinical state and 11 healthy control subjects were studied. Resting energy expenditure (REE) was measured by standard methods of indirect calorimetry, using a ventilated canopy. Premeal REE was measured after an overnight fast. All subjects then received a balanced liquid test meal with a caloric content that was 0.3 times their REE extrapolated to 24 h. Diet-induced thermogenesis was measured over 130 min. Premeal REE was 109.9 +/- 11.7% of predicted values in the COPD group and 97.5 +/- 9.6% of predicted in the control group (p < 0.01). Seventy minutes after the test meal, REE had increased by 18.8 +/- 8.5% in the COPD group and by 15.1 +/- 5.8% in the control group (NS). After 130 min, REE had increased by 16.4 +/- 7.1% in the COPD group and by 12.4 +/- 5.3% in the control group (NS). The DIT expressed as a percentage of the caloric content of the meal was 4.3 +/- 1.6% in the COPD group and 3.3 +/- 1.4% in the control group (NS). We conclude that patients with stable COPD, although hypermetabolic at rest, do not show an increased DIT.

Fouilles suisses à Derecik, Büyükorhan, province de Bursa (Turquie). Rapport préliminaire 2007-2008

La découverte en 2001 d'une église et de son pavement sur le site de Derecik près de la ville de Büyükorhan en Turquie a suscité de premières fouilles par les archéologues du Musée archéologique de Bursa, capitale de province, la même année. La présentation des mosaïques en 2006 aux participants d'un colloque organisé par l'Université Uludag de Bursa a permis l'intervention d'une équipe suisse sur les lieux dès 2007. Deux années de fouille et d'observations ont conduit à distinguer plusieurs phases de construction de l'église elle-même et de l'emplacement sur lequel elle est implantée. Un temple de construction légère l'a précédée, vraisemblablement dédié à Zeus, et au moins trois phases de construction la caractérisent, complétées par des aménagements postérieurs. L'occupation des lieux est attestée depuis le IIe siècle ap. J.-C., sinon avant, jusqu'aux invasions arabes du VIIIe siècle ap. J.-C.

The effects of sevoflurane and halothane anesthesia on cerebral blood flow velocity in children.

We compared cerebral blood flow velocity during anesthesia with sevoflurane and halothane in 23 children admitted for elective surgery (age, 0.4-9.7 yr; median age, 1.9 yr; ASA physical status I-II). Inhaled induction was performed in a randomized sequence with sevoflurane or halothane. Under steady-state conditions, cerebral blood flow velocity (systolic [V(s)], mean [V(mn)], and diastolic [VD]) were measured by a blinded investigator using transcranial pulsed Doppler ultrasonography. The anesthetic was then changed. CBFV measurements were repeated after washout of the first anesthetic and after steady-state of the second (equivalent minimal alveolar concentration to first anesthetic). The resistance index was calculated. VD and V(mn) were significantly lower during sevoflurane (V(mn) 1.35 m/s) than during halothane (V(mn) 1.50 m/s; P = 0.001), whereas V(s) was unchanged. The resistance index was lower during halothane (P < 0.001). Our results indicate lower vessel resistance and higher mean velocity during halothane than during sevoflurane. IMPLICATIONS: The mean cerebral blood flow velocity is significantly decreased in children during inhaled anesthesia with sevoflurane than during halothane. This might be relevant for the choice of anesthetic in children with risk of increased intracranial pressure, neurosurgery, or craniofacial osteotomies.

Development of a novel headspace sorptive extraction method to study the aging of volatile compounds in spent handgun cartridges

Estimating the time since the last discharge of firearms and/or spent cartridges may be a useful piece of information in forensic firearm-related cases. The current approach consists of studying the diffusion of selected volatile organic compounds (such as naphthalene) released during the shooting using solid phase micro-extraction (SPME). However, this technique works poorly on handgun car-tridges because the extracted quantities quickly fall below the limit of detection. In order to find more effective solutions and further investigate the aging of organic gunshot residue after the discharge of handgun cartridges, an extensive study was carried out in this work using a novel approach based on high capacity headspace sorptive extraction (HSSE). By adopting this technique, for the first time 51 gunshot residue (GSR) volatile organic compounds could be simultaneously detected from fired handgun cartridge cases. Application to aged specimens showed that many of those compounds presented significant and complementary aging profiles. Compound-to-compound ratios were also tested and proved to be beneficial both in reducing the variability of the aging curves and in enlarging the time window useful in a forensic casework perspective. The obtained results were thus particularly promising for the development of a new complete forensic dating methodology.

Traitement des sténoses sous-glottiques de l'enfant par résection crico-trachéale [Treatment of subglottis stenosis in children by cricotracheal resection].

Fifty-eight infants and children with a severe subglottic stenosis underwent a partial cricotracheal resection with primary thyrotracheal anastomosis. There were 2 grade II, 40 grade III, and 16 grade IV stenoses according to the Myer-Cotton classification. A 100% subglottic lumen was formed in 34 cases and a better than 80% lumen in 23 cases. Fifty-four of the 58 (93%) patients are presently decannulated; one patient sustained a complete restenosis and three patients with a better than 80% subglottic airway still await decannulation for the following reasons: severe tracheomalacia, bilateral cricoarytenoïd joint fixation and laryngeal malformation with fusion of the vocal cords in each case respectively. Forty-four patients have no exercise intolerance, 8 live fully normally but present a slight exertional dyspnea, one patient with a laryngeal malformation is decannulated but suffers from a severe exertional dyspnea, and 4 patients are still not decannulated. The voice is normal in 20 cases, a slight dysphonia is present in 17, a moderate to severe dysphonia in another 17 and 4 patients are still not decannulated.