8,611 research outputs found
The effects of increasing the risk perception of high-risk behaviors on decision making among college daily smokers and never-smokers
Participation in high-risk behaviors, such as substance use or dangerous driving practices, is widely reported by young adults and college students. Psychosocial theories explain participation in high-risk behaviors by the effects of risk perception on the outcome of behavior. Physiological researchers assert that biological factors (such as the role of the prefrontal cortex) better account for participation in high-risk behaviors based on impulsive decision-making patterns in substance users. The current study explored the relationship between impulsive decision-making and risk perception by assessing the impact of changes in high-risk perceptions on a measure of impulsive decision-making (delay discounting task). A sample of college daily cigarette smokers (n=32) and never-smokers (n=32), participants at particular risk for problems with substance use and other high-risk behaviors, was used. This study demonstrated that an intervention presenting normative information using motivational interviewing techniques significantly changed multiple perceptions and predicted involvement in high-risk behaviors among the entire sample (p \u3c 0.05), as well as the experimental group’s performance on the delay discounting task (t(31) = 1.75, p \u3c 0.05). While perceptions of high-risk behaviors and delay discounting task performance changed within this sample, scores on the delay discounting task and scores on a measure of high-risk perceptions did not significantly correlate prior to or following the intervention. Daily smokers and never-smokers did not differ in delay discounting task performance, but daily smokers reported significantly more positive risk perceptions and greater predicted involvement in drug and alcohol use than never smokers. Results suggest that changes in risk perception can influence delay discounting task performance, but smoking status doesn’t appear to moderate this association
An alternative approach to field-aligned coordinates for plasma turbulence simulations
Turbulence simulation codes can exploit the flute-like nature of plasma
turbulence to reduce the effective number of degrees of freedom necessary to
represent fluctuations. This can be achieved by employing magnetic coordinates
of which one is aligned along the magnetic field. This work presents an
approach in which the position along the field lines is identified by the
toroidal angle, rather than the most commonly used poloidal angle. It will be
shown that this approach has several advantages. Among these, periodicity in
both angles is retained. This property allows moving to an equivalent
representation in Fourier space with a reduced number of toroidal components.
It will be shown how this duality can be exploited to transform conventional
codes that use a spectral representation on the magnetic surface into codes
with a field-aligned coordinate. It is also shown that the new approach can be
generalised to get rid of magnetic coordinates in the poloidal plane
altogether, for a large class of models. Tests are carried out by comparing the
new approach with the conventional approach employing a uniform grid, for a
basic ion temperature gradient (ITG) turbulence model implemented by the two
corresponding versions of the ETAI3D code. These tests uncover an unexpected
property of the model, that localized large parallel gradients can
intermittently appear in the turbulent regime. This leaves open the question
whether this is a general property of plasma turbulence, which may lead one to
reconsider some of the usual assumptions on micro-turbulence dynamics.Comment: 19 pages (once in pdf format). 1 LaTeX file and 10 eps figures in the
zip folde
Elastic Behavior of Oligolamellar Structures
Synovial fluid provides essential boundary lubrication for diarthrodial joints including the hips, knee, and many other joints in humans. While the structure, molecular components, and properties of synovial fluid are relatively well understood, several theories exist for the mechanism of lubrication. Multilamellar phospholipid structures are believed to be an essential part of the lubricating mechanism, yet the study of the mechanical properties has received little attention from the scientific community. Here we investigate the elastic response of multilamellar phospholipid structures under anisotropic compression using coarse grain molecular dynamics. Various hydration levels are considered in order to develop a relationship between hydration and rupture pressure. This is then used to describe membrane elasticity in terms of hydration. Two regimes of elasticiy are found. Additionally some variation is found between current LAMMPS simulations and previous studies conducted in Gromacs
Distributed-Memory Breadth-First Search on Massive Graphs
This chapter studies the problem of traversing large graphs using the
breadth-first search order on distributed-memory supercomputers. We consider
both the traditional level-synchronous top-down algorithm as well as the
recently discovered direction optimizing algorithm. We analyze the performance
and scalability trade-offs in using different local data structures such as CSR
and DCSC, enabling in-node multithreading, and graph decompositions such as 1D
and 2D decomposition.Comment: arXiv admin note: text overlap with arXiv:1104.451
Relationships among performance on simulated tasks of decision-making, positive outcome expectancies for MDMA, and age of first MDMA use
The purpose of this study was to examine relationships among 3,4-methylendioxymethamphetamine (MDMA) use patterns and beliefs, the Gambling Task, the delay discounting task, and the Adult Self-Report (ASR). Sixty-eight college students completed measures of substance use, social desirability, the MDMA Beliefs Questionnaire (MDMA-BQ), the Gambling Task, the delay discounting task, and the ASR. Contrary to predictions, participants who had used MDMA at least once did not vary from those who had never used MDMA on the Gambling Task, the delay discounting task, or the ASR. As predicted, MDMA users’ outcome expectancies for MDMA significantly differed from non-users. MDMA-BQ scales and age of first MDMA use were not correlated with Gambling Task, delay discounting task, or ASR scores. No relationships were found among Gambling Task, delay discounting task, and ASR scores
Personality and television program preference
The first step in this process is to define what is implied by the term Uses and Gratifications and to elaborate on current perspectives of the uses and gratifications paradigm in order to understand the need for the present research. As the second step in this process. a discussion of the variable of audience personality will be explored in order to describe why some of the people exhibit different preferences for different television program content. The end result of this discussion on personality and program preference will be a contribution to the body or heuristic knowledge surrounding the reasons for specific television behaviors by the audience
Decreasing Unnecessary Pharmacy Cost in the Cath Lab
AngioMax is a single dose heparin alternative introduced in 2002 that is used in cardiac patients undergoing percutaneous intervention (PCI). Bivalirudin costs 15 per dose. Noting practice variations, the Cath Lab set out to eliminate unnecessary pharmacy cost for PCI patients by: Using current literature to inform clinical care Standardizing practice Using data to track and guide implementationhttps://digitalcommons.centracare.com/nursing_posters/1097/thumbnail.jp
Progress in Technology Validation of the Next Ion Propulsion System
The NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system has been in advanced technology development under the NASA In-Space Propulsion Technology project. The highest fidelity hardware planned has now been completed by the government/industry team, including a flight prototype model (PM) thruster, an engineering model (EM) power processing unit, EM propellant management assemblies, a breadboard gimbal, and control unit simulators. Subsystem and system level technology validation testing is in progress. To achieve the objective Technology Readiness Level 6, environmental testing is being conducted to qualification levels in ground facilities simulating the space environment. Additional tests have been conducted to characterize the performance range and life capability of the NEXT thruster. This paper presents the status and results of technology validation testing accomplished to date, the validated subsystem and system capabilities, and the plans for completion of this phase of NEXT development
- …