The umbrella-term ‘executive functions’ includes various domain-general, goal-directed cognitive abilities responsible for behavioral self-regulation. The influential unity and diversity model of EF posits the existence of three correlated yet separable executive domains: inhibition, shifting and updating. These domains may be influenced by factors such as socioeconomic status and culture, possibly due to the way EF tasks are devised and to biased choice of stimuli, focusing on first-world testees. Here, we propose a FREE test battery that includes two open-access tasks for (...) each of the three abovementioned executive domains to allow latent variables to be obtained. The tasks were selected from those that have been shown to be representative of each domain, that are not copyrighted and do not require special hardware/software to be administered. These tasks were adapted for use in populations with varying SES/schooling levels by simplifying tasks/instructions and using easily recognized stimuli such as pictures. Items are answered verbally and tasks are self-paced to minimize interference from individual differences in psychomotor and perceptual speed, to better isolate executive from other cognitive abilities. We tested these tasks on 146 early adolescents of both sexes and varying SES, because this is the age group in which the executive domains of interest become distinguishable and in order to confirm that SES effects were minimized. Performance was determined by Rate Correct Scores, which consider speed-accuracy trade-offs. Scores were sensitive to the expected improvement in performance with age and rarely/inconsistently affected by sex and SES, as expected, with no floor or ceiling effects, or skewed distribution, thus suggesting their adequacy for diverse populations in these respects. Using structural equation modeling, evidence based on internal structure was obtained by replicating the three correlated-factor solution proposed by the authors of the model. We conclude that the FREE test battery, which is open access and described in detail, holds promise as a tool for research that can be adapted for a wide range of populations, as well as altered and/or complemented in coming studies. (shrink)

A general practice research project on ethics is underway at the University of New South Wales, funded by GPEP (General Practice Evaluation Program, Commonwealth Department of Human Services and Health, GPEP 386). Ethical issues, as defined and explored by general practitioners and consumers, are being examined across four areas of Sydney.So far, telephone interviews have been conducted (64% response rate) with a random sample of general practitioners (GPs). Face-to-face interviews have been conducted with 107 consumers, randomly sampled using ABS collection (...) district information. Focus groups have been formed to discuss acceptable solutions to GP and consumer identified ethical issues. This report will report on some preliminary findings to date and will explore professional and consumer roles in the formation of ethical solutions. (shrink)

A general practice research project on ethics is underway at the University of New South Wales, funded by GPEP. Ethical issues, as defined and explored by general practitioners and consumers, are being examined across four areas of Sydney.So far, telephone interviews have been conducted with a random sample of general practitioners. Face-to-face interviews have been conducted with 107 consumers, randomly sampled using ABS collection district information. Focus groups have been formed to discuss acceptable solutions to GP and consumer identified ethical (...) issues. This report will report on some preliminary findings to date and will explore professional and consumer roles in the formation of ethical solutions. (shrink)

In this paper, the Helmholtz equation with quadratic damping themes is used for modeling the dynamics of a simple prey-predator system also called a simple Lotka–Volterra system. From the Helmholtz equation with quadratic damping themes obtained after modeling, the equilibrium points have been found, and their stability has been analyzed. Subsequently, the harmonic oscillations have been studied by the harmonic balance method, and the phenomena of resonance and hysteresis are observed. The primary and secondary resonances have been researched by the (...) multiple-scale method, and the conditions of stability of the amplitudes of oscillations are determined. Chaos is detected analytically by the Melnikov method and numerically using the basin of attraction, the bifurcation diagram, the Lyapunov exponent, the phase portrait, and the Poincaré section. The effects of all the parameters of the system are analyzed in detail, and special emphasis is placed on the new parameters. Through this analysis, the complex phenomena such as hysteresis, bistability, amplitude jump, resonances, and chaos have been obtained. The control of the parameters and the necessary conditions to control the aforementioned phenomena have been found. (shrink)