Changing Urban High Schools

This report chronicles a Cross City Campaign working meeting co-sponsored by the Annenberg Institute for School Reform

Spitzer observations of Bow Shocks and Outflows in RCW 38

We report Spitzer observations of five newly identified bow shocks in the massive star-forming region RCW 38. Four are visible at IRAC wavelengths, the fifth is visible only at 24 microns. Chandra X-ray emission indicates that winds from the central O5.5 binary, IRS~2, have caused an outflow to the NE and SW of the central subcluster. The southern lobe of hot ionised gas is detected in X-rays; shocked gas and heated dust from the shock-front are detected with Spitzer at 4.5 and 24 microns. The northern outflow may have initiated the present generation of star formation, based on the filamentary distribution of the protostars in the central subcluster. Further, the bow-shock driving star, YSO 129, is photo-evaporating a pillar of gas and dust. No point sources are identified within this pillar at near- to mid-IR wavelengths. We also report on IRAC 3.6 & 5.8 micron observations of the cluster DBS2003-124, NE of RCW 38, where 33 candidate YSOs are identified. One star associated with the cluster drives a parsec-scale jet. Two candidate HH objects associated with the jet are visible at IRAC and MIPS wavelengths. The jet extends over a distance of ~3 pc. Assuming a velocity of 100 km/s for the jet material gives an age of about 30,000 years, indicating that the star (and cluster) are likely to be very young, with a similar or possibly younger age than RCW 38, and that star formation is ongoing in the extended RCW 38 region.Comment: 27 pages, 6 figures, accepted to Ap

The role of monetary incentives in prediction markets: a time series approach

Prediction markets serve as popular devices to aggregate beliefs and to assess market estimated probabilities. By looking at the interaction between real- and play-money prediction markets, this paper shows that traded volume has a significant positive effect on the probability of real- and play-money market cointegration. This indicates that the information aggregation process, eliminating individual traders'' biases, operates even when not inducing truthful belief revelation with monetary incentives. The study is based on data from four markets covering the 2008 presidential election in the United States of Americafinancial economics and financial management ;

Natural resource scarcity and technological change

Nonrenewable natural resources, such as aluminum and crude oil, exist only in fixed amounts on Earth. Consequently, some observers are concerned that natural resource scarcity will eventually limit future economic growth and human well-being. Others remain optimistic that technological change will overcome geophysical scarcity. Brown and Wolk examine the evidence for natural resource scarcity and find that over the past century reliance on free markets has promoted sufficient technological change to overcome geophysical scarcity for most nonrenewable natural resources. Rather than rising--as would result from increased scarcity--the relevant real prices of most nonrenewable natural resources have fallen. Although declines in real prices have moderated since World War II, the authors find little evidence of increased scarcity in the postwar era. Increased reliance on markets during the closing decades of the twentieth century is cause for optimism that these trends will continue in the twenty-first.