Six H ii regions at galactocentric distances of R ¼ 10 15 kpc have been observed in the far-IR emission lines of [O iii] (52 m, 88 m), [ N iii] (57 m), and [S iii] (19 m) using the Kuiper Airborne Observatory. These observations have been combined with Very Large Array radio continuum observations of these sources to determine the abundances of O ++ , N ++ , and S ++ relative to hydrogen. In addition, eight of the most recent sets of measurements of ionic line strengths in H ii regions have been reanalyzed in order to attempt to reconcile differences in optical versus far-IR abundance determinations. We have in total 168 sets of observations of 117 H ii regions in our analysis. The new analysis included updating the atomic constants (transition probabilities and collision cross sections), recalculation of some of the physical conditions in the H ii regions (n e and T e), and the use of new photoionization models to determine stellar effective temperatures of the exciting stars. We also use the most recent data available for the distances for these objects, although for most we still rely on kinematic distance determinations. Our analysis finds little indication of differences between optical and infrared observations of the nitrogen abundances, but some differences are seen in the oxygen and sulfur abundances. A very significant offset continues to be seen between optical and infrared measurements of the N/O abundance ratio.
We present the results of a national study on the teaching and learning of astronomy as taught in general education, non-science-major, introductory astronomy courses. Nearly 4000 students enrolled in 69 sections of courses taught by 36 different instructors at 31 institutions completed ͑preand post-instruction͒ the Light and Spectroscopy Concept Inventory ͑LSCI͒ from Fall 2006 to Fall 2007. The classes varied in size and were from all types of institutions, including 2-and 4-year colleges and universities. Normalized gain scores for each class were calculated. Pre-instruction LSCI scores were clustered around ϳ25%, independent of class size and institution type, and normalized gain scores varied from about −0.07 to 0.50. To estimate the fraction of classroom time spent on learner-centered, active-engagement instruction we developed and administered an Interactivity Assessment Instrument ͑IAI͒. Our results suggest that the differences in gains were due to instruction in the classroom, not the type of class or institution. We also found that higher interactivity classes had the highest gains, confirming that interactive learning strategies are capable of increasing student conceptual understanding. However, the wide range of gain scores seen for both lower and higher interactivity classes suggests that the use of interactive learning strategies is not sufficient by itself to achieve high student gain.
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