Towards an understanding of assimilation in virtual worlds: the 3C approach

Virtual worlds are increasing in importance as more multi-national firms are investing heavily in these emerging communities. Although much excitement has surrounded the idea of virtual worlds, a gap exists between those who register and those who engage in virtual worlds. Our analysis of the gap between those who merely register to join a virtual world and those who ultimately engage the community on a regular basis derives from a lack of assimilation. We present the 3C approach, a high-level theoretical framework delineating the relationship between three classes of factors (namely the technology class of factors; the community class of factors; and the user class of factors) that we posit explain virtual world assimilation and employ theories to represent these classes of factors and the interaction between them. After discussing and integrating these three classes of factors, we test our model through a study of 223 new users of Second Life. The results provide empirical support for the 3C framework; specifically, our analysis indicates that the technology and community classes of factors in exert a direct influence upon a user's attitude towards the virtual world, and this relationship is moderated by the user class of factors.     

Evaluation of cattle bedding and grazing BMPs in an agricultural watershed in Alberta

This paper highlights the environmental impacts of implementing beneficial management practices to address cattle bedding and direct access to the creek in a study watershed in southern Alberta, Canada. Approximately 35 cow-calf pairs grazed 194 ha of grass forage and had direct access to the creek in the spring and summer. During winter, the cattle were fed adjacent to the creek at an old bedding site. The practice changes included off-stream watering, bedding site relocation and fencing for rotational grazing. The cost was $15,225 and 60 h of labour. Four years of data were used in a before-and-after experimental design to evaluate the practice changes. After two years of post-implementation monitoring, riparian assessments showed an increase in plant diversity, but no change in the percent cover of the riparian species Salix exigua and Juncus balitus and a decrease in Carex sp. (P < 0.05). Water quality monitoring showed a decrease in the difference between upstream and downstream concentrations of total phosphorus, total dissolved phosphorus, total nitrogen, organic nitrogen and Escherichia coli (P < 0.10). These results showed that improved environmental changes in riparian and water quality can be measured following the implementation of beneficial management practices for cattle bedding and grazing.     

Effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat

This study examined the separate effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat. Participants (N = 10) performed three trials in a counterbalanced order, either with 400 mg caffeine, menthol lozenges, or placebo. The simulated firefighting consisted of 2 bouts of 20-min treadmill exercise and one bout of 20-min stepping exercise in the heat with two brief 15-min rest periods between each exercise phase. Exercise induced significant dehydration (>3%) and elevated rectal temperature (>38.9 °C), for all three conditions. Neither caffeine nor menthol reduced perceived exertion compared to placebo (p > 0.05). Mood ratings (i.e., alertness, hedonic tone, tension) significantly deteriorated over time (p < 0.05), but there was no difference among the three conditions. Simple reaction time, short-term memory, and retrieval memory did not alter with treatments or repeated evaluations. Reaction accuracy from a math test remained unchanged throughout the experimental period; reaction time from the math test was significantly faster after exposure to the heat (p < 0.05). It is concluded that, exhaustive exercise in the heat severely impacted mood, but minimally impacted cognition. These treatments failed to show ergogenic benefits in a simulated firefighting paradigm in a hot environment.     

Interfacial tension measurements and evidence of order in high‐density polyethylene melts

Polyethylene (PE) is a widely used product commercially. However, our knowledge is incomplete about the properties of high‐density polyethylene (HDPE) at temperatures above its melting point, where solid crystals disappear. Recently, there has been increasing evidence from rheological, differential scanning calorimetry, and NMR studies that suggests the presence of microstructural order in the bulk of PE melts. In this study, the interfacial tension of HDPE melts in contact with silicone oil was measured with a spinning drop tensiometer in the same temperature range in which phase transitions have been observed in the bulk HDPE. Anomalous temperature dependence of interfacial tension was found between 200 and 230°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4061–4067, 2003     

General Ability Index for the WAIS-III: Canadian Norms.

The Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; Wechsler, 1997) permits the calculation of both traditional IQ and Index scores. The Verbal Comprehension and Perceptual Organization indexes are the most highly "g" loaded compared to the Working Memory and Processing Speed indexes that may be more sensitive to some neuro-cognitive disorders. In certain clinical situations, a general ability composite score based on the combination of only the verbal and performance indexes is desirable. Following the procedure for calculating a General Ability Index (GAI; Prifitera, Weiss, & Saklofske, 1998) for the Wechsler Intelligence Scale for Children-Third Edition (WISC-HI; Wechsler, 1991) and the WAIS-III (Tulsky, Saklofske, Wilkins, & Weiss, 2001), GAI normative tables for the WAIS-III Canadian standardization sample are reported here to complement earlier published GAI Canadian norms tables for the WISC-III. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Randomized Trial Comparing the Effects of Self-Help Materials and Proactive Telephone Counseling on Teen Smoking Cessation.

We conducted a 2-arm randomized trial to test the efficacy of self-help materials with or without proactive telephone counseling to increase cessation among teen smokers. Teen smokers (N = 402) recruited from 11 shopping malls and 1 amusement park in the southeastern United States were randomized to 1 of 2 groups: written self-help material plus video; or written self-help material, video, and telephone counseling. Cessation rates based on 7-day point-prevalent abstinence for the self-help and counseling arms were 11% and 16%, respectively (p = .25), at 4 months postbaseline and 19% and 21%, respectively (p = .80), at 8 months postbaseline. Sustained abstinence, reflecting 7-day abstinence at both time points, in the self-help and counseling arms was 7% and 9% (p = .59). Results suggest that minimal self-help cessation approaches that target youth have comparable success to that shown among adult smokers. However, refinements in telephone-counseling approaches may be needed to achieve the success observed in adult populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Focused Ultrasound Preconditioning for Augmented Nanoparticle Penetration and Efficacy in the Central Nervous System

Microbubble activation with focused ultrasound (FUS) facilitates the noninvasive and spatially‐targeted delivery of systemically administered therapeutics across the blood–brain barrier (BBB). FUS also augments the penetration of nanoscale therapeutics through brain tissue; however, this secondary effect has not been leveraged. Here, 1 MHz FUS sequences that increase the volume of transfected brain tissue after convection‐enhanced delivery of gene‐vector “brain‐penetrating” nanoparticles were first identified. Next, FUS preconditioning is applied prior to trans‐BBB nanoparticle delivery, yielding up to a fivefold increase in subsequent transgene expression. Magnetic resonance imaging (MRI) analyses of tissue temperature and K_trans confirm that augmented transfection occurs through modulation of parenchymal tissue with FUS. FUS preconditioning represents a simple and effective strategy for markedly improving the efficacy of gene vector nanoparticles in the central nervous system.     

A user-assisted approach to visualizing multidimensional images

We present a new technique for fusing together an arbitrary number of aligned images into a single color or intensity image. We approach this fusion problem from the context of Multidimensional Scaling (MDS) and describe an algorithm that preserves the relative distances between pairs of pixel values in the input (vectors of measurements) as perceived differences in a color image. The two main advantages of our approach over existing techniques are that it can incorporate user constraints into the mapping process and allows adaptively compressing or exaggerating features in the input in order to make better use of the output's limited dynamic range. We demonstrate these benefits by showing applications in various scientific domains and comparing our algorithm to previously proposed techniques.     

What primary care psychology has to offer the patient-centered medical home.

The Patient-Centered Medical Home (PCMH) proposes a new model to transform the practice of primary health care to one that is patient centered, high quality, continuous, comprehensive, and compassionate. In this paper, the authors provide an updated definition of, and skills needed for, primary care psychology, focused on integrating various psychological approaches with an overarching systemic theory. With this in mind, the authors suggest that primary care psychology can be important to achieving the goals of what some professionals now call the Patient-Centered Health Care Home. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reinforcing value of physical activity as a determinant of child activity level.

This study examined whether the relative reinforcing value of physical activity (RRVPA) measured in the laboratory predicted physical activity measured in the natural environment in 32 6–11-year-old children. RRVPA correlated with physical activity level (r?=?.42, p?r?=?.35, p?