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.     

Analysis of Satisfaction and Perceived Learning of Science in Different Distance Education Delivery Modes for Rural Elementary School Teachers Involved in a Professional Development Project

The Science Co-op is a local systemic change project that connects eight regional clusters of elementary schools in rural Missouri and Iowa in the USA. These clusters are comprised of 38 school districts distributed over 40,000 square miles and include more than 1,400 teachers and 20,000 elementary school students. The project stresses inquiry science in the classroom and involves investigating science ideas using a constructivist approach and cross-curricular connections. Within the frameworks of the Science Co-op project a technology known as Interactive Television (ITV) allows for almost real-time interaction (a 3–5 second delay) within the state boundaries of Missouri and Iowa, respectively. The primary goals of the ITV sessions are to enhance the science content and science pedagogical knowledge among the population of elementary school teachers that they may have lacked in their prior education, and to reinforce and extend instructional strategies emphasized in this local systemic change project. In this study the participants' self-reported learning and reactions to live ITV sessions and videotaped, delayed broadcast of ITV sessions were compared. Regression analysis results show teaching experience's influence on overall satisfaction with ITV (p<0.05) while mode attended, perceived technical difficulty, preferred mode, and perceived new skills or content learned in the session entered the regression equation at p=.000. Further t-tests suggested p>0.05 for perceived new skills and content learned on the different modes of communication.     

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.     

Evaluating college campus closings for the 1980s: A case application of an optimization model

Institutional administrators, faculty, state planners, and legislatures have little analytical basis available to help them cope with the expected excess higher education capacity of the 1980s. Without objective criteria, state planners and legislatures are likely to propose across-the-board reductions even if it were preferable to close some institutions and expand others. This study is a case application of an optimization model to two community colleges in northern Minnesota. Using estimated enrollment demand functions and readily available data on size, quality, and costs, this model is designed to assist policymakers in identifying overbuilt institutions and programs that should be closed. The state's objective in the model is to satisfy specified proportions of enrollment demand with a minimum expenditure of state funds.     

Mainstreaming the Hearing Impaired Student‐‐An Area of Preparation Responsibility for Teacher Training Programs: A Pilot Study

Interviewing, as an information‐gathering tool for prospective teachers of the deaf, was used to document the perspectives which deaf children, their parents, teachers and administrators bring to the mainstreaming process. Data revealed the different, and sometimes competing priorities of mainstreaming participants; these priorities are discussed in terms of their impact upon the success or failure of the mainstreaming process and the preparation responsibilities of teacher training programs.     

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.     

A Loyalty Tax? National Measures of Academic Salary Compression

This paper presents measures of faculty salary compression for 1993 and 1999 based on national, rather than institutional-level, data. Using a recently developed technique and two national faculty surveys, actual junior to senior salary ratios are derived as well as predicted salary ratios that represent what the salary ratios would be if junior and senior faculty were similarly compensated for their productive traits. The analysis, which considers three alternative definitions of junior faculty and stratifies results by institutional type, produces an overall finding of no salary compression. A limited number of disciplines, including business and economics, however, do exhibit signs of salary compression.     

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.