Developing Seventh Grade Students’ Understanding of Complex Environmental Problems with Systems Tools and Representations: a Quasi-experimental Study

A systems-based classroom intervention on environmental education was designed for seventh grade students; the results were evaluated to see its impact on the development of systems thinking skills and standard science achievement and whether the systems approach is a more effective way to teach environmental issues that are dynamic and complex. A quasi-experimental methodology was used to compare performances of the participants in various dimensions, including systems thinking skills, competence in dynamic environmental problem solving and success in science achievement tests. The same pre-, post- and delayed tests were used with both the comparison and experimental groups in the same public middle school in Istanbul. Classroom activities designed for the comparison group (N = 20) followed the directives of the Science and Technology Curriculum, while the experimental group (N = 22) covered the same subject matter through activities benefiting from systems tools and representations such as behaviour over time graphs, causal loop diagrams, stock-flow structures and hands-on dynamic modelling. After a one-month systems-based instruction, the experimental group demonstrated significantly better systems thinking and dynamic environmental problem solving skills. Achievement in dynamic problem solving was found to be relatively stable over time. However, standard science achievement did not improve at all. This paper focuses on the quantitative analysis of the results, the weaknesses of the curriculum and educational implications.     

Adaptive synchronization of chaotic Colpitts circuits against parameter mismatches and channel distortions

In this work, synchronization of chaotic Colpitts circuits, using adaptive controllers to combat circuit parameter mismatches and channel distortions, is studied by numerical simulations. Synchronization errors caused by different main circuit components are compared, and compensation for time-constant and time-varying circuit parameter mismatches is demonstrated. Different kinds of channel distortions, including time-constant and time-varying channel attenuation, Additive White Gaussian Noise (AWGN) are all investigated by numerical simulations and discussed. Simulation results indicated that the synchronization performance of chaotic Colpitts circuits can be greatly improved by applying adaptive controllers when parameter mismatches and channel attenuation are considered as time-constant or time-varying, but have no obvious enhancements regarding the effect on AWGN channel.     

Behavioral and Electrophysiological Evidence for Gestational Age Effects in Healthy Preterm and Fullterm Infants Studied Two Weeks after Expected Due Date

We investigated the effects of gestational age at birth on behavioral and electrophysiological measures of 135 medically healthy infants, studied at 42 weeks postconception, and stratified into 3 groups--early-born preterms, 26-32 weeks (n = 55); middle-group preterms, 33-37 weeks (n = 43); and fullterms, 38-41 weeks (n = 37). Subjects were studied behaviorally with the Assessment of Preterm Infants' Behavior (APIB) and electrophysiologically with brain electrical activity mapping (BEAM). Fullterms showed significantly better behavioral function than both preterm groups. Less difference was found between the preterm groups. EEG spectral and photic evoked response were of significantly less amplitude for the preterms than the fullterms. Path analysis showed gestational age effects on behavioral (3 of 6) and electrophysiological (13 of 17) variables due to postnatal complications. We conclude that some differences attributable to gestational age at birth are explained by the cumulative effect of minor but unavoidable complications associated with premature birth. We speculate that remaining effects may result from developmentally inappropriate sensorimotor stimulation consequent to the premature experience of an extrauterine environment.     

Simple model for gas holdup and liquid velocity of annular photocatalytic external-loop airlift reactor under both bubble and developing slug flow

Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external- loop airlift reactor(AELAR)in the bubble flow and developing slug flow pattern. Experiments were performed by using tap-water and silicone oil with the viscosity of 2.0 mm²/s(2cs-SiO)and 5.0 mm²/s(5cs-SiO)as liquid phases. The effects of liquid viscosity and flow pattern on the AELAR performance were investigated. The predictions of the proposed model were in good agreement with the experimental results of the AELAR. In addition, the comparison of the experimental results shows that the proposed model has good accuracy and could be used to predict the gas holdup and liquid velocity of an AELAR operating in bubble and developing flow pattern.     

Nobel Prize in Physics 2006

The discovery of the cosmic microwave background radiation in 1965 was a defining moment in the history of cosmology — the science that deals with the universe as a whole, its origin, evolution and future. This discovery was recognized with Nobel Prizes to Penzias and Wilson in 1978. The Nobel Prize in Physics for 2006 further acknowledged the importance of the study of this background radiation. The precise measurement of the spectrum of this radiation and its variation across the sky have helped our understanding of the evolution of structures in the universe. This article explains these discoveries and their importance. T Padmanabhan is a professor at IUCAA, Pune. He is interested in all aspects of theoretical physics, and especially in those in which gravity plays a role.     

Noise assisted directed motion at the molecular level — 2

The term noise is used to describe fluctuations about the mean deterministic stationary value of a physical quantity. It is now being increasingly realised that noise is an important ingredient to bring order in dynamical processes. Though it appears counterintuitive, noise seems to help in directing transport processes in biological systems at the molecular level. In Part 2 of the article, we discuss some more examples of noise assisted directed motion.     

The Journey Toward Transformational Learning in a Statewide Doctoral Program

This article describes strategies for redesigning the University of Missouri's Statewide Cooperative Ed.D. Cohort Program in educational leadership. Results had suggested a need to redesign aspects of the program in order to achieve higher levels of cognitive learning outcomes inclusive of transformational learning. To help meet this objective, the areas targeted for redesign were the curriculum as it relates to issues of diversity and ethics, instruction as it relates to group dynamics and cohort models, and increased time and a forum for students to reflect on their leadership practices. This forum also allowed faculty to monitor and assess the transformational learning outcomes of their students. This article is meant to assist others who are interested in fostering higher levels of transformational learning outcomes within their programs. Meredith L. Mountford holds a Bachelor of Science degree from Illinois State University, a Master of Science degree in educational administration from Northern Illinois University and a Philosophy of Science degree in educational administration from the University of Wisconsin—Madison. She is an Assistant Professor and has served as Director for the Statewide Cooperative Ed.D. Cohort Program in educational leadership at the University of Missouri—Columbia.