Inverting chaos: Extracting system parameters from experimental data.

Given a set of experimental or numerical chaotic data and a set of model differential equations with several parameters, is it possible to determine the numerical values for these parameters using a least-squares approach, and thereby to test the model against the data? We explore this question (a) with simulated data from model equations for the Rossler, Lorenz, and pendulum attractors, and (b) with experimental data produced by a physical chaotic pendulum. For the systems considered in this paper, the least-squares approach provides values of model parameters that agree well with values obtained in other ways, even in the presence of modest amounts of added noise. For experimental data, the "fitted" and experimental attractors are found to have the same correlation dimension and the same positive Lyapunov exponent. (c) 1996 American Institute of Physics.

Occupational exposure to dial painters and assemblers of radioluminous timepieces.

An evaluation of available personnel monitoring data and radium body burden records of dial painters handling an annual average of 1.5 Ci of radium indicates that they received an average of about 2 rem/person whole body exposure, 3 rem to the lungs from radon inhalation and 0.2 rad to the bone from radium body burdens. Among groups of similar workers handling tritium in Texas plants, the highest occupational exposures were about 160 mrem annually per person received by refinishers of tritium dial timepieces and back-lit watch assemblers. Based upon scenarios of exposures to 147Pm, repairers of timepieces containing 147Pm receive about 4.4 X 10(-4) mrem/person/yr whole body dose equivalent. The amounts that they process are in the microcurie range. Although the trend is away from the use of radium as a luminizing activator, there are indications that it is still used in timepieces even as tritium and 147Pm are increasingly being used for this purpose.

An interdisciplinary educational model for health professions students in a family practice center.

Health professions students have little or no opportunity to practice together during their formative stages of development. Therefore, can we realistically expect them to practice together as professionals? This is an important area for educators to address, given the current emphasis on interdisciplinary collaboration. The authors describe an interdisciplinary education program model for nursing, medicine, and social work students in a family practice center.

Achieving a multicultural service orientation. Adaptive models in service delivery and race and culture training.

Human beings cannot be tossed together under the assumption that well-intentioned care will create a harmonious union. A multicultural service orientation does not eliminate all problems, but it does help reduce the likelihood of racial and cultural conflict between caregiver and client.

The influence of personality, curriculum, and memory correlates on formal reasoning in young adults and elderly persons.

The study examined the effects of age, sex, and curriculum upon the cognitive performance of 20 college students and 20 college-educated elderly individuals. Participants were given a battery of formal operational tasks, a measure of field independence/field dependence, a memory-span measure, and a measure of tolerance of ambiguity. The results revealed a lack of significant age differences in any of the measures of formal reasoning. Gender and curriculum, however, were significant predictors of cognitive performance for both cohort groups. These results suggest that within this select sample formal operational thought abilities are present.

Modifiability of figural relations performance among elderly adults.

This study examined the relative efficacy of two figural relations training strategies in improving cognitive performance in healthy, well-functioning elderly individuals (N = 69; aged 62 to 92). Participants were randomly assigned to a no-contact control group (n = 24), a training group that received formal instructions in principles underlying figural relations problem solution (n = 24), or a self-instructed interactive group that received practice with the figural relations training materials but no formal instruction (n = 21). All participants took a pretest battery and posttests on two occasions following training that tapped a variety of cognitive abilities. Planned comparisons indicated that the experimental groups differed significantly from the control group at the first posttest as well as across both posttest occasions on near versus far transfer tasks. However, self-generated strategies for task solution were found to be more durable over time as compared to specific rule training on near versus far transfer.