Anisotropy of the Microwave Sky at 90 GHz: Results from Python II

We report on additional observations of degree scale anisotropy at 90~GHz from the Amundsen-Scott South Pole Station in Antarctica. Observations during the first season with the Python instrument yielded a statistically significant sky signal; in this paper we report the confirmation of that signal with data taken in the second year, and on results from an interleaving set of fields.Comment: 10 pages, plus 2 figures. Postscript and uufiles versions available via anonymous ftp at ftp://astro.uchicago.edu/pub/astro/ruhl/pyI

All sky CMB map from cosmic strings integrated Sachs-Wolfe effect

By actively distorting the Cosmic Microwave Background (CMB) over our past light cone, cosmic strings are unavoidable sources of non-Gaussianity. Developing optimal estimators able to disambiguate a string signal from the primordial type of non-Gaussianity requires calibration over synthetic full sky CMB maps, which till now had been numerically unachievable at the resolution of modern experiments. In this paper, we provide the first high resolution full sky CMB map of the temperature anisotropies induced by a network of cosmic strings since the recombination. The map has about 200 million sub-arcminute pixels in the healpix format which is the standard in use for CMB analyses (Nside=4096). This premiere required about 800,000 cpu hours; it has been generated by using a massively parallel ray tracing method piercing through a thousands of state of art Nambu-Goto cosmic string numerical simulations which pave the comoving volume between the observer and the last scattering surface. We explicitly show how this map corrects previous results derived in the flat sky approximation, while remaining completely compatible at the smallest scales.Comment: 8 pages, 4 figures, uses RevTeX. References added, matches published versio

Primordial helium recombination II: two-photon processes

Interpretation of precision measurements of the cosmic microwave background (CMB) will require a detailed understanding of the recombination era, which determines such quantities as the acoustic oscillation scale and the Silk damping scale. This paper is the second in a series devoted to the subject of helium recombination, with a focus on two-photon processes in He I. The standard treatment of these processes includes only the spontaneous two-photon decay from the 2^1S level. We extend this treatment by including five additional effects, some of which have been suggested in recent papers but whose impact on He I recombination has not been fully quantified. These are: (i) stimulated two-photon decays; (ii) two-photon absorption of redshifted HeI line radiation; (iii) two-photon decays from highly excited levels in HeI (n^1S and n^1D, with n>=3); (iv) Raman scattering; and (v) the finite width of the 2^1P^o resonance. We find that effect (iii) is highly suppressed when one takes into account destructive interference between different intermediate states contributing to the two-photon decay amplitude. Overall, these effects are found to be insignificant: they modify the recombination history at the level of several parts in 10^4.Comment: 19 pages, 11 figures, to be submitted to PR

Absorption of Ultrashort Laser Pulses in Strongly Overdense Targets

We report on the first absorption experiments of sub-10 fs high-contrast Ti:Sa laser pulses incident on solid targets. The very good contrast of the laser pulse assures the formation of a very small pre-plasma and the pulse interacts with the matter close to solid density. Experimental results indicate that p-polarized laser pulses are absorbed up to 80 percent at 80 degrees incidence angle. The simulation results of PSC PIC code clearly confirm the observations and show that the collisionless absorption works efficiently in steep density profiles

The Production Function of the Regulatory State

How much will our budget be cut be this year? This question has loomed ominously over regulatory agencies for over three decades. After the 2016 presidential election, it now stands front and center in federal policy, with the Trump administration pledging over $50 billion in cuts. Yet very little is known about the fundamental relationship between regulatory agencies’ budgets and the social welfare outcomes they are charged to produce. Indeed, the question is scarcely studied in scholarship from law, economics, or political science. This article lays the groundwork for a new field of theoretical and empirical research, using what we call the “regulatory production function,†to understand the marginal effects of changes in regulatory agency budgets (both reductions and increases) on the levels of benefits they produce. Our proposed theoretical framework and empirical findings have important implications across the regulatory state on the relationship between agency funding and outcomes for public health, safety, and welfare agencies. This model of the regulatory state informs agency-scale decisions regarding institutional design and instrument choice as well as the broader set of decisions regarding the balance of federalism and reliance on private governance as a supplement to public authority. Part I describes relevant scholarship on the broad topic of regulatory agency resources and outcomes, showing a paucity of theoretical and empirical analysis of the question. Using the Environmental Protection Agency (EPA) and environmental quality as a case study, Part II develops a conceptual model of a regulatory production function for thinking more clearly about linkages between agency funding and regulatory outcomes. Using this model, Part III turns to generating hypotheses that could explain why EPA funding levels may or may not have a strong effect on environmental quality. Part IV uses regression analyses to test whether there is a statistically significant relationship between agency funding and air pollution. In the face of significant data and modeling constraints, we found none. Part V then explores the important research questions that emerge from the study and proposes a research agenda going forward. Much as the tools of cost-benefit analysis and risk assessment have transformed the study of policy choice and legal design, development of the regulatory production function model and the data needed to study it will allow scholars to examine fundamental questions of the regulatory state

Oral Lesions in Passerine and Psittacine Birds: A Differential Diagnosis

Imagine that you are a recently graduated veterinarian working for a mixed animal practice which serves a moderately populated area. One of your more regular clients presents to you a cockatiel which was purchased six months ago. The owner describes a two week history of dysphagia, anorexia, loss of weight and a general loss of activity. Upon physical examination the most outstanding lesions consisted of white, moderately raised areas of well circumscribed nodules and fibronecrotic plaques in the oral cavity

Impact of reionization on CMB polarization tests of slow-roll inflation

Estimates of inflationary parameters from the CMB B-mode polarization spectrum on the largest scales depend on knowledge of the reionization history, especially at low tensor-to-scalar ratio. Assuming an incorrect reionization history in the analysis of such polarization data can strongly bias the inflationary parameters. One consequence is that the single-field slow-roll consistency relation between the tensor-to-scalar ratio and tensor tilt might be excluded with high significance even if this relation holds in reality. We explain the origin of the bias and present case studies with various tensor amplitudes and noise characteristics. A more model-independent approach can account for uncertainties about reionization, and we show that parametrizing the reionization history by a set of its principal components with respect to E-mode polarization removes the bias in inflationary parameter measurement with little degradation in precision.Comment: 9 pages, 6 figures; submitted to Phys. Rev.