Radial basis functions: Developments and applications to planetary scale flows

Radial basis functions (RBFs) can be seen as a major generalization of pseudospectral (PS) methods, abandoning the orthogonality of the basis functions and in return obtaining much improved simplicity and geometric flexibility. Spectral accuracy becomes now easily available also when using completely unstructured node layouts, permitting local node refinements in critical areas. The first major PDE applications for which RBFs have been shown to compete successfully against the best currently available numerical approaches can be found in the geosciences. Examples that are discussed here include translating vortex roll-ups (cyclogenesis), nonlinear flows on the sphere modeled by the shallow water equations, and 3D convection in the earth’s mantle.     

The effect of auditory distraction on the useful field of view in hearing impaired individuals and its implications for driving

This study assessed whether the increased demand of listening in hearing impaired individuals exacerbates the detrimental impact of auditory distraction on a visual task (useful field of view test), relative to normally hearing listeners. Auditory distraction negatively affects this visual task, which is linked with various driving performance outcomes. Hearing impaired and normally hearing participants performed useful field of view testing with and without a simultaneous listening task. They also undertook a cognitive test battery. For all participants, performing the visual and auditory tasks together reduced performance on each respective test. For a number of subtests, hearing impaired participants showed poorer visual task performance, though not to a statistically significant extent. Hearing impaired participants were significantly poorer at a reading span task than normally hearing participants and tended to score lower on the most visually complex subtest of the visual task in the absence of auditory task engagement. Useful field of view performance is negatively affected by auditory distraction, and hearing loss may present further problems, given the reductions in visual and cognitive task performance suggested in this study. Suggestions are made for future work to extend this study, given the practical importance of the findings.     

Fitness-to-drive after mild traumatic brain injury: Mapping the time trajectory of recovery in the acute stages post injury

Introduction

Little is known about the trajectory of recovery in fitness-to-drive after mild traumatic brain injury (mTBI). This means that health-care professionals have limited evidence on which to base recommendations to this cohort about driving.

Objective

To determine fitness-to-drive status of patients with a mTBI at 24 h and two weeks post injury, and to summarise issues reported by this cohort about return to driving.

Method

Quasi-experimental case-control design. Two groups of participants were recruited: patients with a mTBI (n = 60) and a control group with orthopaedic injuries (n = 60). Both groups were assessed at 24 h post injury on assessments of fitness-to-drive. Follow-up occurred at two weeks post injury to establish driver status.

Main Measures

Mini mental state examination, occupational therapy-drive home maze test (OT–DHMT), Road Law Road Craft Test, University of Queensland-Hazard Perception Test, and demographic/interview form collected at 24 h and at two weeks.

Results

At the 24 h assessment, only the OT–DHMT showed a difference in scores between the two groups, with mTBI participants being significantly slower to complete the test (p = 0.01). At the two week follow-up, only 26 of the 60 mTBI participants had returned to driving. Injury severity combined with scores from the 24 h assessment predicted 31% of the variance in time taken to return to driving. Delayed return to driving was reported due to: “not feeling 100% right” (n = 14, 23%), headaches and pain (n = 12, 20%), and dizziness (n = 5, 8%).

Conclusion

This research supports existing guidelines which suggest that patients with a mTBI should not to drive for 24 h; however, further research is required to map factors which facilitate timely return to driving.     

Dextran sulfate sodium inhibits alanine synthesis in caco-2 cells

To understand and characterize the pathogenic mechanisms of inflammatory bowel disease, dextran sulfate sodium (DSS) has been used to induce acute and chronic colitis in animal models by causing intestinal epithelium damage. The mechanism of action of DSS in producing this outcome is not well understood. In an effort to understand how DSS might impact epithelial cell metabolism, we studied the intestinal epithelial cell line Caco-2 incubated with 1% DSS over 56 hours using (1)H NMR spectroscopy. We observed no difference in cell viability as compared to control cultures, and an approximately 1.5-fold increase in IL-6 production upon incubation with 1% DSS. The effect on Caco-2 cell metabolism as measured through changes in the concentration of metabolites in the cell supernatant included a three-fold decrease in the concentration of alanine. Given that the concentrations of other amino acids in the cell culture supernatant were not different between treated and control cultures over 56 hours suggest that DSS inhibits alanine synthesis, specifically alanine aminotransferase, without affecting other key metabolic pathways. The importance of alanine aminotransferase in inflammatory bowel disease is discussed.     

Structural and electrochemical behavior of LiMn0.4Ni0.4Co0.2O2

Layered LiMn_0.4Ni_0.4Co_0.2O₂ with the α-NaFeO₂ structure was synthesized by the “mixed hydroxide” method, followed by a high temperature calcination at 800 °C giving a single phase material of surface area 5 m² g⁻¹. A combined X-ray/neutron diffraction Rietveld refinement showed that the transition metals in the 3b layer are randomly distributed at room temperature, and that only nickel migrates to the lithium layer and in this case 4.4%. Addition of excess lithium reduces the amount of nickel on the lithium sites. The magnetic susceptibilities of the compounds LiMn_yNi_yCo_1−2yO₂ (y = 0.5, 0.4, 0.333) follow the Curie–Weiss law above 100 K and are consistent with the presence of Ni²⁺, Mn⁴⁺ and Co³⁺ cations; their magnetization curves, measured at 5 K and showing a pronounced hysteresis, are also consistent with the nickel content on the lithium sites increasing with decreasing cobalt content. This material shows a stable capacity of 140–170 mA h g⁻¹ for more than 90 cycles within the voltage window of 2.5–4.4 V. The layered rhombohedral structure is maintained as lithium is removed down to at least a lithium content of 0.05; the total volume change on cycling is under 2%. The nickel ions pin the lattice so that MO₂ slab sliding to form the 1T structure cannot readily occur. The capability of aqueous acids to leach lithium from the lattice decreases with increasing nickel content in the lithium layer; however, the thermal stability of the delithiated compounds increases with cobalt content.     

Cultivation and characterization of pterygium as an ex vivo study model for disease and therapy

Purpose

Development of ex vivo model to study pathogenesis, inflammation and treatment modalities for pterygium.

Perceptual biases, affect, and behavior in the relationships of dependents and self-critics.

Aspects of interpersonal, personality, and cognitive models of depression were tested in a college sample. The perceptions and actual interpersonal behaviors of dependent and self-critical women and their romantic partners were assessed during a conflict-resolution task. Dependent women were characterized by positive biases in the perception of lovingness expressed within the relationship. The partners of dependent women, however, experienced a decrease in positive affect and a trend toward increasing hostility during the conflict-resolution task. Self-critical women were objectively rated as less loving and more hostile, and their partners were also rated as less loving. Self-critics also exhibited negative biases in self-perceptions of submissiveness. The results are interpreted within a comprehensive framework integrating various elements of interpersonal, personality, and cognitive models of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interpersonal problem-solving interactions of depressed adolescents and their parents.

Research to date suggests that the family plays a significant role in the development, perpetuation, and relapse of depression in its members. This study examined the videotaped interactions of parents with a depressed adolescent and control parents and youth during a conflictual, problem-solving task. In comparison with parents of nondepressed adolescents, parents of depressed adolescents engaged in higher rates of incongruent communication in which aversive content behavior was linked with positive affective behavior. Adolescent depressed content behavior led to greater suppression of parent aversive content behavior in nondepressed families than in depressed families. The findings argue that dysfunctional family communication may be associated with the development or maintenance of depression in the child. (PsycINFO Database Record (c) 2010 APA, all rights reserved)