Do You Always Need a Textbook to Teach Astro 101?

The increasing use of interactive learning strategies in Astro 101 classrooms has led some instructors to consider the usefulness of a textbook in such classes. These strategies provide students a learning modality very different from the traditional lecture supplemented by reading a textbook and homework, and raises the question of whether the learning that takes place during such interactive activities is enough by itself to teach students what we wish them to know about astronomy. To address this question, assessment data is presented from an interactive class, which was first taught with a required textbook, and then with the textbook being optional. Comparison of test scores before and after this change shows no statistical difference in student achievement whether a textbook is required or not. In addition, comparison of test scores of students who purchased the textbook to those who did not, after the textbook became optional, also show no statistical difference between the two groups. The Light and Spectroscopy Concept Inventory (LSCI), a research-validated assessment tool, was given pre- and post-instruction to three classes that had a required textbook, and one for which the textbook was optional, and the results demonstrate that the student learning gains on this central topic were statistically indistinguishable between the two groups. Finally, the Star Properties Concept Inventory (SPCI), another research-validated assessment tool, was administered to a class for which the textbook was optional, and the class performance was higher than that of a group of classes in a national study

Can gravitational waves be detected in quasar microlensing?

Studies of the lensed quasar ${\rm Q}0957+561 {\rm A,B}$ have shown evidence for microlensing in the brightness history of the quasar images. It had been suggested that a frequency offset between the brightness fluctuations in each of the two images might possibly be caused by gravitational radiation generated by a massive black hole binary at the center of the lensing galaxy. This paper demonstrates that the fluctuations produced by such a source of gravitational waves will be too small to account for the observed frequency offsets.Comment: 10 pages, 1 fig; submitted to Ap

Have Recent Budget Policies Contributed to Long-Run Fiscal Stability?

Examines developments in budget policies since January 2010; the president's 2011 budget, including economic stimulus and tax and spending policies; congressional action; and issues for health reform. Considers their effect on long-term sustainability

Committees Tackle the Deficit

Summarizes the recommendations of a presidential commission and private bipartisan committee for reducing the federal deficit by cutting healthcare costs, Social Security outlays, and discretionary spending, and by raising taxes

The applicability of MFD thrusters to satellite power systems

The high power self field MPD thruster uses electromagnetic forces rather than electrostatic to accelerate a neutral plasma. The most attractive application of MPD thrusters to satellite power systems is in the area of electric propulsion for a cargo orbit transfer vehicle (COTV). Calculations were performed in order to compare the performance of a COTV using an ion or MPD propulsion system. Results show that the MPD propulsion system gives a shorter trip time with the same power and payload when compared to the ion thruster propulsion system at either value of specific impulse. More important than the trip time benefit may be the advantage a MPD propulsion system provides in system simplicity. Another interesting COTV concept using MPD thrusters is the use of a remote power supply located on the Earth, at GEO, or somewhere in between to transmit power to the COTV in a microwave transmission. The specific impulse at thrust levels of tens of newtons makes a MPD propulsion system a candidate for stationkeeping and attitude control of large space structures such as a SPS

Correlation and Fluctuation in Multiparticle Production: Some Closing Remarks

Some general comments are made on the evolution of this series of workshops and on some features of this particular Workshop without attempting to summarize all the talks presented.Comment: Closing talk at the 11th Workshop on Correlation and Fluctuation in Multiparticle Production, Hangzhou, China, Nov. 21-24, 200

Controlling the Deficit: The Debate Continues

Looks at budget cuts proposed by House Republicans and the president's framework with respect to savings in healthcare spending, Social Security and other entitlement spending, and discretionary spending; tax policy; and the Budget Control Act

A study of health and safety practices in small and medium sized enterprises: -A case of Botswana

TThe purpose of this research is to understand the views of different employees in small and medium enterprises about what can be done to improve the health and safety in work places. In order to carry out this research, questionnaires were used to collect the views of different employees concerning this topic in these organizations, and literature was also reviewed. From the findings ,it shows that when good health and safety practices are not put in place, accidents ,major and minor injuries can happen, and it is what most of the employees in other companies have so far experienced. This implies that if health and safety is not managed effectively, both the two parties being employees and the organization would suffer because for the organization to function effectively, it needs employees and for the people to survive, they need to work.health, safety, injury, accident