Anti-Semitism and apostasy in Nineteenth-Century France: A response to Jonathan Helfand

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43005/1/10835_2005_Article_BF01668931.pd

A Bow Shock Nebula Around a Compact X-Ray Source in the Supernova Remnant IC443

We present spectra and high resolution images of the hard X-ray feature along the southern edge of the supernova remnant IC443. Data from the Chandra X-ray Observatory reveal a comet-shaped nebula of hard emission, which contains a softer point source at its apex. We also present 20cm, 6cm, and 3.5cm images from the Very Large Array that clearly show the cometary nebula. Based on the radio and X-ray morphology and spectrum, and the radio polarization properties, we argue that this object is a synchrotron nebula powered by the compact source that is physically associated with IC443. The spectrum of the soft point source is adequately but not uniquely fit by a black body model (kT=0.71 +/- 0.08 keV, L=(6.5 +/- 0.9) * 10^31 erg/s). The cometary morphology of the nebula is the result of the supersonic motion of the neutron star (V_NS=250 +/- 50 km/s), which causes the relativistic wind of the pulsar to terminate in a bow shock and trail behind as a synchrotron tail. This velocity is consistent with an age of 30,000 years for the SNR and its associated neutron star.Comment: 9 pages, 5 figures, accepted for publication in the ApJ Letter

The frankaus of London: A study in radical assimilation, 1837–1967

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43006/1/10835_2005_Article_BF01915911.pd

Greenhouse Gas Reductions Under Low Carbon Fuel Standards?

A low carbon fuel standard (LCFS) seeks to reduce greenhouse gas emissions by capping an industry’s carbon emissions per unit of output. California has launched an LCFS for automotive fuels; others have called for a national LCFS. We show that this policy causes production of high-carbon fuels to decrease but production of low-carbon fuels to increase. The net effect of this may be an increase in carbon emissions. The LCFS may also reduce welfare, and the best LCFS may be no LCFS. We simulate the outcomes of a national LCFS, focusing on gasoline and ethanol as the high- and low-carbon fuels. For a broad range of parameters, we find that the LCFS is unlikely to increase CO2 emissions. However, the surplus losses from the LCFS are quite large ($80 to$760 billion annually for a national LCFS reducing carbon intensities by 10 percent), and the average carbon cost ($307 to$2,272 per ton of CO2 for the same LCFS) can be much larger than damage estimates. We propose an efficient policy that achieves the same emissions reduction at a much lower surplus cost ($16 to$290 billion) and much lower average carbon cost ($60 to$868 per ton of CO2). ∗We thank Douglas Miller and Burkhard Schipper for helpful discussions. Knittel and Hughes thank financia