Estimating Column Density in Molecular Clouds with FIR and Sub-mm Emission Maps

We have used a numerical simulation of a turbulent cloud to synthesize maps of the thermal emission from dust at a variety of far-IR and sub-mm wavelengths. The average column density and external radiation field in the simulation is well matched to clouds such as Perseus and Ophiuchus. We use pairs of single-wavelength emission maps to derive the dust color temperature and column density, and we compare the derived column densities with the true column density. We demonstrate that longer wavelength emission maps yield less biased estimates of column density than maps made towards the peak of the dust emission spectrum. We compare the scatter in the derived column density with the observed scatter in Perseus and Ophiuchus. We find that while in Perseus all of the observed scatter in the emission-derived versus the extinction-derived column density can be attributed to the flawed assumption of isothermal dust along each line of sight, in Ophiuchus there is additional scatter above what can be explained by the isothermal assumption. Our results imply that variations in dust emission properties within a molecular cloud are not necessarily a major source of uncertainty in column density measurements.Comment: Accepted to ApJ Letter

Economic impact of large public programs: The NASA experience

The economic impact of NASA programs on weather forecasting and the computer and semiconductor industries is discussed. Contributions to the advancement of the science of astronomy are also considered

Dominion Resources: Powering Section 1341 Toward Equity?

Administrative concerns occasionally override other aspects of tax policy. One example is the imposition of an annual reporting cycle which leads taxpayers to make assumptions about future events so that items can be reported on regularly scheduled returns. This can result in reporting items as income that are not actually earned by the taxpayer. For example, under the claim of right doctrine, created because of the annual reporting requirement, taxpayers must report certain receipts as income even though they are later required to return these amounts to the payor. In most cases they are permitted a deduction in the year that the cash is returned. However, this deduction may not fully offset the prior taxation due to rate changes and other items. As a partial remedy Congress enacted Section 1341 which allows taxpayers to calculate the tax reduction from the repayment based on the tax paid on the inclusion. The IRS has attempted to limit the application of Section 1341. In Dominion Resources, the courts reviewed the rules adopted by IRS and prior courts and applied a better reasoned, more equitable approach. The limited scope of the case did not permit the court to review all of the limitations imposed on this Section over the years and apply a consistent approach. This article will discuss the case as well as areas in which the court could, in the future, adopt its reasoning to arrive at a more equitable approach to Section 1341

The Gas Temperature of Starless Cores in Perseus

In this paper we study the determinants of starless core temperatures in the Perseus molecular cloud. We use NH3 (1,1) and (2,2) observations to derive core temperatures (T_kin) and data from the COMPLETE Survey of Star Forming Regions and the c2d Spitzer Legacy Survey for observations of the other core and molecular cloud properties. The kinetic temperature distribution probed by NH3 is in the fairly narrow range of 9 - 15 K. We find that cores within the clusters IC348 and NGC1333 are significantly warmer than "field" starless cores, and T_kin is higher within regions of larger extinction-derived column density. Starless cores in the field are warmer when they are closer to class O/I protostars, but this effect is not seen for those cores in clusters. For field starless cores, T_kin is higher in regions in which the 13CO linewidth and the 1.1mm flux from the core are larger, and T_kin is lower when the the peak column density within the core and average volume density of the core are larger. There is no correlation between T_kin and 13CO linewidth, 1.1mm flux, density or peak column density for those cores in clusters. The temperature of the cloud material along the line of sight to the core, as measured by CO or far-infrared emission from dust, is positively correlated with core temperature when considering the collection of cores in the field and in clusters, but this effect is not apparent when the two subsamples of cores are considered separately.Comment: Accepted to ApJ; 13 pages, including 3 tables and three figure

The Origin of the Claim Test: A Search for Objectivity

Recently, the Ninth Circuit Court of Appeals, in United States v. Kroy (Europe) Ltd., used the origin of the claim test to determine the deductibility of financing expenses. At approximately the same time, the Tax Court, in Fort Howard Corp. v. Commissioner, concluded the use of the origin of the claim test to characterize similar expenditures was inappropriate. Given this conflict and the extensive use of this test to evaluate the deductibility of expenditures, this article reviews the development of this test and provides an analysis of the potential conflicts and uncertainties in its application

Construction and Measurements of an Improved Vacuum-Swing-Adsorption Radon-Mitigation System

In order to reduce backgrounds from radon-daughter plate-out onto detector surfaces, an ultra-low-radon cleanroom is being commissioned at the South Dakota School of Mines and Technology. An improved vacuum-swing-adsorption radon mitigation system and cleanroom build upon a previous design implemented at Syracuse University that achieved radon levels of $\sim$0.2$\,$Bq$\,$m$^{-3}$. This improved system will employ a better pump and larger carbon beds feeding a redesigned cleanroom with an internal HVAC unit and aged water for humidification. With the rebuilt (original) radon mitigation system, the new low-radon cleanroom has already achieved a $>$$\,$300$\times$ reduction from an input activity of $58.6\pm0.7$$\,$Bq$\,$m$^{-3}$ to a cleanroom activity of $0.13\pm0.06$$\,$Bq$\,$m$^{-3}$.Comment: 5 pages, 4 figures, Proceedings of Low Radioactivity Techniques (LRT) 2015, Seattle, WA, March 18-20, 201