Impact of the ice strength formulation on the performance of a sea ice thickness distribution model in the Arctic

The impact of a subgrid-scale ice thickness distribution (ITD) and two standard ice strength formulations on simulated Arctic sea ice climate is investigated. To this end, different model configurations with and without an ITD were tuned by minimizing the weighted mean error between the simulated and observed sea ice concentration, thickness, and drift speed with an semiautomatic parameter optimization routine. The standard ITD and ice strength parameterization lead to larger errors when compared to the simple single-category model with an ice strength parameterization based on the mean ice thickness. Interestingly, the simpler ice strength formulation, which depends linearly on the mean ice thickness, also reduces the model-observation error when using an ITD. For the ice strength parameterization that makes use of the ITD, the effective ice strength depends strongly on the number of thickness categories, so that introducing more categories can lead to overall thicker ice that is more easily deformed

Landfast ice in the Kara Sea reduces the subsurface salinity in the central Arctic Ocean

Landfast ice is sea ice that is attached to the coastline via its tensile strength, grounding to the ocean floor from pressure ridges in the Stamukhi region, or anchoring on offshore islands. Fast ice is a platform used by local communities for hunting, traveling and a place for oil and gas drilling and scientific observation. Previous work shows that adding tensile strength to sea ice in regions of shallow bathymetry in order to simulate represent landfast ice in models improves the simulation of the halocline and thermohaline circulation by changing the location of new ice formation and brine rejection at the edge of landfast ice in coastal polynya. However, the impact of fast ice presence or absence in coastal regions with deeper bathymetry (e.g. Kara Sea) on the Arctic hydrography remains unknown. In this contribution, we compare the simulated hydrography in the full Arctic with and without landfast ice parameterization that allows for a landfast ice cover in deep coastal region through lateral anchoring with land --- something not resolved in coarse ice-ocean models. Results show a fresher upper ocean signal when landfast ice is present --- because of the isolating effect of stable ice cover --- that is advected eastward from the Kara Sea to the Makarov Basin (north of the Laptev Sea) via Vilkitsky Strait, suggesting a proper landfast ice simulation in the Kara Sea influences the hydrography in the Arctic and the circulation of Atlantic and Pacific water below the halocline

Portrait des activités délinquantes et de l’usage de substances psychoactives chez des jeunes consultant un centre de réadaptation pour personnes alcooliques et toxicomanes

Près de 900 jeunes présentant une problématique sévère de toxicomanie ont été évalués lors de leur demande de service en centre spécialisé. Un portrait de leur consommation de substances psychoactives est dressé et comparé en fonction des types d’encadrement judiciaire auquel est soumis l’individu, mais aussi en fonction du sexe. On constate des variations importantes de consommation de drogues entre les groupes (jeunes contrevenants par rapport aux jeunes en situation de protection ou encore, sous aucun encadrement légal) permettant d’appuyer l’hypothèse de liens entre, d’une part, l’intensité et le type de consommation de substances psychoactives et, d’autre part, la gravité des activités délictueuses. On tente d’identifier la portion de délits commis pour des fins de consommation de substances psychoactives et, donc, d’évaluer la proportion de jeunes qui cesseraient probablement les activités délictueuses si on pouvait les aider à cesser cette consommation de drogues. Les différences entre les sexes sont également mises en évidence.Nearly 900 heavy alcohol or drug adolescent users were evaluated at their admission into a substance abuse center. Description of their alcohol and drug use is done in interaction with the legal status in which they are embedded but also by sex. Differences are observed between groups (offenders versus the child welfare or without legal restrictions). Those differences give support to the presumed link between severity of substances abuse and importance of criminality. Efforts are made to calculate proportions of subjects for which criminal activities would presumably reduce or stopped by the instauration of abstinence. Differences between sexes are also analyzed

Active training and driving-specific feedback improve older drivers' visual search prior to lane changes

<p>Abstract</p> <p>Background</p> <p>Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses) do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving.</p> <p>Methods</p> <p>In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group). Their results were compared to a Control group (12 older drivers) who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback.</p> <p>Results</p> <p>After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot). In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes).</p> <p>Conclusions</p> <p>These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.</p

Multiple Exposition to a Driving Simulator Reduces Simulator Symptoms for Elderly Drivers

This study examines how older drivers responded to repeated exposures to a driver simulator. Older active and fit drivers participated in 5 simulator sessions within a 14-day period. For each session, simulator sickness symptoms were measured with the Simulator Sickness Questionnaire at baseline and post-session. In addition, participants completed a 10-cm visual analog scale (0= no symptom, 10= mild nausea) at baseline and after a familiarization scenario and post-session. Overall, older adults adapted to the driving simulator and by the fourth session, they showed no difference in sickness scores between the baseline and the post-session measurements. Increasing the exposure duration at session 5 yielded an increase in the sickness symptoms. These results suggest that shorterduration multiple exposures could reduce simulator sickness symptoms in elderly drivers and allow a more effective use of simulators for training by preventing early withdrawal of participants

Multiple-Session Simulator Training for Older Drivers and On-Road Transfer of Learning

Driving retraining classes may offer an opportunity to attenuate some of the aging manifestation that may alter driving skills. Unfortunately, there are suggestions that classroom programs do not allow to improve the driving performance of elderly drivers. The aim of this study was to evaluate if specific simulator training sessions with video-based feedback can modify on-road behaviors of elderly drivers. In order to evaluate the effectiveness of the training, 10 elderly drivers who received feedback were tested before and after the training program with an on-road standardized evaluation. A control group (12 older drivers) also participated. Participants in this group received a classroom training program and similar exposure to driving in a simulator but without drivingspecific feedback. After attending the training program, the control group showed no modification of their driving performance (on-road score, frequency of successful turning maneuvers and frequency blind spot verification before lane change maneuvers). On the other hand, participants in the feedback group improved their driving skills for all maneuvers that were evaluated. These results suggest that simulator training transferred effectively to on-road performance. In order to be effective, driving programs should include active practice sessions with driving specific feedback