An evaluation of graduated driver licensing programs in North America using a meta-analytic approach

Most jurisdictions in North America have some version of graduated driver licensing (GDL). A sound body of evidence documenting the effectiveness of GDL programs in reducing collisions, fatalities and injuries among novice drivers is available. However, information about the relative importance of individual components of GDL is lacking. The objectives of this study are to calculate a summary statistic of GDL effectiveness and to identify the most effective components of GDL programs using a meta-analytic approach. Data from 46 American States, the District of Columbia and 11 Canadian jurisdictions are used and were obtained from the Fatality Analysis Reporting System (FARS) for the U.S. and from Transport Canada's Traffic Accident Information Database (TRAID) for Canada. The timeframe of this evaluation is 1992 through 2006, inclusive. Relative fatality risks and their 95% confidence intervals were calculated using fatality counts and population data for target and comparison groups, both in a pre-implementation and post-implementation period in each jurisdiction. The target groups were 16-, 17-, 18- and 19-year-old drivers. The comparison group was 25–54-year-old drivers. The relative fatality risks of all jurisdictions were summarized using the random effects DerSimonian and Laird model. Meta-regression using Restricted Maximum Likelihood (REML) and Markov Chain Monte Carlo (MCMC) Gibbs sampling was also conducted. Strong evidence in support of GDL was found. GDL had a positive and significant impact on the relative fatality risk of 16-year-old drivers (reduction of 19.1%). Significant effects were found for meta-regression models with 16-, 18- and 19-year-old drivers. These effects include length of night restriction in the learner stage, country, driver education in the learner stage and in the intermediate stage, whether night restrictions are lifted in the intermediate stage for work purposes, passenger restriction in the intermediate stage, whether passenger restrictions in the intermediate stage are lifted if passengers are family members, and whether there is an exit test in the intermediate stage. In conclusion, several GDL program components have an important effect on the relative fatality risk of novice drivers. These results help understand how such effects are achieved.     

Influence of the microstructure of aluminium alloys on their residual impact properties after a fatigue loading program

Consecutive loadings of fatigue and impact have been carried out on aluminium alloys. The aim of this study is to quantify the influence of the microstructure on the residual impact behavior after a prior fatigue loading. Two alloys with different chemical compositions and hardening modes have been investigated: 2017A-T3 used in the aircraft industry and 5454-O used in automotive applications.The fatigue pre-loadings were carried out under fully reversed tensile-compression with several pairs (stress level, number of cycles) in the high cycle fatigue zone (10⁵– 10⁶cycles). The residual impact behavior was determined under tensile loading, in the range of medium strain rates (about ). To assess the prior fatigue damage and to follow its evolution during the impact loading, observation of the specimens (surface and fracture surfaces) were made.From this study, two conclusions have been highlighted: (1) there is no direct correlation between a given prior loading and residual behavior, whatever the material; (2) the material aspect is fundamental. At the mechanical (macroscopic) scale, the Al–Mg alloy (5454-O) remains insensitive to the prior fatigue loading whereas the Al–Cu alloy (2017A-T3) undergoes a large modification in its residual performance. At a lower scale, the pre-damage signature appears for the insensitive as well as for the sensitive material. The prior damage and its contribution to the process fracture appear to be strongly linked with the material’s microstructure.     

It's the thought that counts: The role of hostile cognition in shaping aggressive responses to social exclusion.

Prior research has confirmed a casual path between social rejection and aggression, but there has been no clear explanation of why social rejection causes aggression. A series of experiments tested the hypothesis that social exclusion increases the inclination to perceive neutral information as hostile, which has implications for aggression. Compared to accepted and control participants, socially excluded participants were more likely to rate aggressive and ambiguous words as similar (Experiment 1a), to complete word fragments with aggressive words (Experiment 1b), and to rate the ambiguous actions of another person as hostile (Experiments 2-4). This hostile cognitive bias among excluded people was related to their aggressive treatment of others who were not involved in the exclusion experience (Experiments 2 and 3) and others with whom participants had no previous contact (Experiment 4). These findings provide a first step in resolving the mystery of why social exclusion produces aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydraulic Conductivity of MSW in Landfills

This paper presents a laboratory investigation of hydraulic conductivity of municipal solid waste (MSW) in landfills and provides a comparative assessment of measured hydraulic conductivity values with those reported in the literature based on laboratory and field studies. A series of laboratory tests was conducted using shredded fresh and landfilled MSW from the Orchard Hills landfill (Illinois, United States) using two different small-scale and large-scale rigid-wall permeameters and a small-scale triaxial permeameter. Fresh waste was collected from the working phase, while the landfilled waste was exhumed from a borehole in a landfill cell subjected to leachate recirculation for approximately 1.5 years. The hydraulic conductivity tests conducted on fresh MSW using small-scale rigid-wall permeameter resulted in a range of hydraulic conductivity 2.8×10?3–11.8×10?3?cm/s with dry unit weight varied in a narrow range between 3.9–5.1?kN/m3. The landfilled MSW tested using the same permeameter produced results between 0.6×10?3–3.0×10?3?cm/s for 4.5–5.5?kN/m3 dry unit weights. The hydraulic conductivity obtained from large-scale rigid-wall permeameter tests decreased with the increase in normal stress for both fresh and landfilled waste. The hydraulic conductivity for fresh MSW ranged from 0.2 cm/s for 4.1?kN/m3 dry unit weight (under zero vertical stress) and then decreased to 4.9×10?5?cm/s for 13.3?kN/m3 dry unit weight (under the maximum applied normal stress of 276 kPa). The hydraulic conductivity of the landfilled MSW decreased from 0.2 cm/s to 7.8×10?5?cm/s when the dry unit weight increased from 3.2 to 9.6?kN/m3. The results clearly demonstrated that the hydraulic conductivity of MSW can be significantly influenced by vertical stress and it is mainly attributed to the increase in density leading to low void ratio. In small-scale triaxial permeameter, when the confining pressure was increased from 69 to 276 kPa the hydraulic conductivity decreased from approximately 10?4?to?10?6?cm/s, which is much lower than those determined from rigid-wall permeameter tests. The published field MSW hydraulic conductivities are found to be higher than the laboratory results. Landfilled MSW possesses lower hydraulic conductivity than fresh MSW due to increased finer particles resulting from degradation. The decreasing hydraulic conductivity with increasing dry unit weight is expressed by an exponential decay function.     

Time perspective in socioeconomic inequalities in smoking and body mass index.

Objective: To determine if time perspective plays a mediating role in the relationship between socio-economic position (SEP) and both smoking and body mass index (BMI). Design: 2000 adults aged 18 years and over were randomly selected from the edited electoral register for the city of Newcastle upon Tyne, England and sent a postal questionnaire. Two reminders were sent. Main outcome measures: Socio-economic position was measured using the Index of Multiple Deprivation (IMD) of the area of residence. Time perspective was measured using the Consideration of Future Consequences Scale (CFCS). Smoking and BMI were self-reported. Results: Full data was available for 804 individuals (response rate: 40.2%). After controlling for age, gender and health status, IMD was significantly associated with BMI, smoking status and CFCS score (p     

Explicit modelling of the double‐gate MOSFET with VHDL‐AMS

This paper presents a new compact model for the undoped, long‐channel double‐gate (DG) MOSFET under symmetrical operation. In particular, we propose a robust algorithm for computing the mobile charge density as an explicit function of the terminal voltages. It allows to greatly reduce the computation time without losing any accuracy. In order to validate the analytical model, we have also developed the 2D simulations of a DG MOSFET structure and performed both static and dynamic electrical simulations of the device. Comparisons with the 2D numerical simulations give evidence for the good behaviour and the accuracy of the model. Finally, we present the VHDL‐AMS code of the DG MOSFET model and related simulation results. Copyright © 2006 John Wiley & Sons, Ltd.     

Efficient Enantioselective Hydrosilylation of Aryl Ketones Catalyzed by a Chiral BINAP‐Copper(I) Catalyst‐Phenyl(methyl)silane System

The Cu(I)‐chiral diphosphine (BINAP) system was found to efficiently catalyze the hydrosilylation of aryl alkyl ketones with excellent enantioselectivities by using phenyl(methyl)silane as stoichiometric hydride source.