Combined effects of alcohol and distraction on driving performance

Although alcohol and distraction are often cited as significant risk factors for traffic crashes, most research has considered them in isolation. It is therefore necessary to consider the interactions between alcohol and distraction impairment sources, especially when examining the relationship between behavior and crash risk. In a driving simulator, the primary goal was to maintain a safe headway to a lead vehicle and the secondary goal was to maintain stable lane position. All participants engaged in distractions that represented different levels of resource competition and half of the participants consumed alcohol (target BAC 0.08 g/dl). Specific comparisons were made between sober driving while distracted and driving intoxicated without distraction. Distraction tasks produced more changes in driving behavior than did alcohol for both longitudinal (primary) and lateral (secondary) driving goals. Alcohol impairment was evident only in relation to lateral driving performance, however there was an amplification of impairment when alcohol and distraction conditions were combined. Distraction resulted in a general level of impairment across all driving goals, whereas participants with alcohol appeared to shed secondary driving goals to “protect” primary driving goals. Drivers’ strategies to cope with alcohol (and distraction) may not be sufficient to offset the increased crash risk.     

Is Solar System Stable? A Remark

It is not yet known (1997) whether the Solar system is stable or not. Common belief is that the Solar system is stable if and only if it is not a resonant system, i.e., whenever its orbital frequencies i satisfy an inequality | nii| for i|ni| N; a similar inequality is true for randomly chosen frequencies. In this paper, we show that the Solar system does not have such resonances, and therefore (if the above-mentioned belief is correct), it is stable.     

Expanding Participation in Undergraduate Research Using the Affinity Group Model*

The benefits of working in a research group are clear: students develop domain expertise, gain an understanding and appreciation of the research process and its practice, and acquire team, communication, problem-solving, and higher-level thinking skills. Students with this experience are better equipped to make informed judgements about technical matters and to communicate and work in teams to solve complex problems. Clearly, this type of research experience must be made available to a broader population. This paper discusses how the Systems and Software Engineering Affinity Research Group model provides a socialization mechanism and infrastructure that supports the development and management of large research groups that engage undergraduate and graduate students, who have a wide range of skill levels and experiences, in research and projects. This non-hierarchical model, which is based on the cooperative paradigm, integrates students into small research groups and an encompassing large research group, and uses structured activities to develop their research, technical, communication, and group skills.     

Effect of Contamination on the Friction and Wear of Carboxylic Acids in Aqueous Lubricants

The friction and wear mechanisms of water-based fluids consisting of various types of carboxylic acids have been systematically investigated using a ball-on-disc tribometer on a super duplex stainless steel under boundary lubricating conditions. Under water-based lubrication, a decrease in friction was found for each of the tested carboxylic acids with a hydrocarbon chain longer than 12 carbon atoms. However, wear reduction was only seen for the carboxylic acids with a hydrocarbon chain longer than 16 carbon atoms or with shorter chain carboxylic acids in concentrations above a critical value. In addition, it was found that when the lubricant is contaminated with bivalent metal ions like Ca²⁺ or Mg²⁺, the frictional performance worsened; however, wear improved. Increasing the concentration of bivalent alkaline metal ions reduced the adsorption ability of carboxylic acids to the steel surface leading to higher friction and the presence of Na⁺ ions facilitated the wear improvement. This is explained by the formation of polyelectrolyte complexes between the metal ions dissolved in the lubricant and the carboxylic acid molecules. To compensate for the detrimental effects in friction, a chelating strategy has been implemented and explained in detail.     

Prevalence of traumatic events and peritraumatic predictors of posttraumatic stress symptoms in a nonclinical sample of college students

This study investigated lifetime prevalence of traumatic events and posttraumatic stress disorder (PTSD) symptoms among 937 college students. Participants rated their lifetime experiences of traumatic events and, in response to their "most stressful" event, completed measures of objective stressor dimensions, PTSD, and peritraumatic reactions. Approximately 67% of respondents reported at least one traumatic event. An estimated 4% of the full sample (12% of traumatized individuals) met PTSD criteria within the past week. After controlling for vulnerability factors and objective characteristics, peritraumatic reactions remained strongly predictive of PTSD symptoms. Results are discussed with respect to immediate reactions to traumatic events as potential precursors of PTSD symptomatology.     

Polymerization of lactams, 94. Formation of cyclic oligomers in anionic polymerization of 6-hexanelactam

HPLC analysis of the methanol-extractable fractions of polymers was used to study the formation of cyclic oligomers during the non-activated anionic polymerization of 6-hexanelactam initiated by sodium or magnesium salt of 6-hexanelactam and ethylmagnesium bromide at 190°C. It was demonstrated that the nature of the counterion of the substance which initiates the anionic polymerization has a crucial effect on the mechanism of the formation of the cyclic oligomers. It was proved that in the course of the 6-hexanelactam polymerization in presence of magnesium compounds, the cyclic oligomer formation is distinctly slower, as compared to the sodium 6-hexanelactam-initiated polymerization.     

Synthesis of Dolichols in Candida albicans Is Co-Regulated with Elongation of Fatty Acids

Protein glycosylation requires dolichyl phosphate as a carbohydrate carrier. Dolichols are α-saturated polyprenols, and their saturation in S. cerevisiae is catalyzed by polyprenyl reductase Dfg10 together with some other unknown enzymes. The aim of this study was to identify such enzymes in Candida. The Dfg10 polyprenyl reductase from S. cerevisiae comprises a C-terminal 3-oxo-5-alpha-steroid 4-dehydrogenase domain. Alignment analysis revealed such a domain in two ORFs (orf19.209 and orf19.3293) from C. albicans, which were similar, respectively, to Dfg10 polyprenyl reductase and Tsc13 enoyl-transferase from S. cerevisiae. Deletion of orf19.209 in Candida impaired saturation of polyprenols. The Tsc13 homologue turned out not to be capable of saturating polyprenols, but limiting its expression reduce the cellular level of dolichols and polyprenols. This reduction was not due to a decreased expression of genes encoding cis-prenyltransferases from the dolichol branch but to a lower expression of genes encoding enzymes of the early stages of the mevalonate pathway. Despite the resulting lower consumption of acetyl-CoA, the sole precursor of the mevalonate pathway, it was not redirected towards fatty acid synthesis or elongation. Lowering the expression of TSC13 decreased the expression of the ACC1 gene encoding acetyl-CoA carboxylase, the key regulatory enzyme of fatty acid synthesis and elongation.     

Shear-Bending-Torsion Interaction in Structural Concrete Members: A Nonlinear Coupled Sectional Approach

Inclined cracks that take place in reinforced concrete elements due to tangential internal forces, such as shear and torsion, produce a non-isotropic response on the structure in the post-cracked regime and up to failure, also known as crack-induced-anisotropy. The result is that all six internal forces acting in a cross-section are generally coupled. A generalized beam formulation for the nonlinear coupled analysis of non-isotropic elements under six internal forces is presented. The theory is based on a cross-section analysis approach with both warping and distortion capabilities, which were proved necessary to correctly handle the problem with frame element analysis. In this paper, the non-linear mechanical aspects of cracked concrete structures under tangential forces are summarized. A state of the art review of beam formulations for the non-linear analysis of concrete structures is presented, and the approaches followed to account for the interaction of shear and torsion forces are discussed. After presenting the proposed formulation, its capabilities are shown by means of an application example of a cross section under coupled bending-shear and torsion, finally main conclusions are drawn.