Neptune's Migration into a Stirred-Up Kuiper Belt: A Detailed Comparison of Simulations to Observations

Nbody simulations are used to examine the consequences of Neptune's outward migration into the Kuiper Belt, with the simulated endstates being compared rigorously and quantitatively to the observations. These simulations confirm the findings of Chiang et al. (2003), who showed that Neptune's migration into a previously stirred-up Kuiper Belt can account for the Kuiper Belt Objects (KBOs) known to librate at Neptune's 5:2 resonance. We also find that capture is possible at many other weak, high-order mean motion resonances, such as the 11:6, 13:7, 13:6, 9:4, 7:3, 12:5, 8:3, 3:1, 7:2, and the 4:1. The more distant of these resonances, such as the 9:4, 7:3, 5:2, and the 3:1, can also capture particles in stable, eccentric orbits beyond 50 AU, in the region of phase space conventionally known as the Scattered Disk. Indeed, 90% of the simulated particles that persist over the age of the Solar System in the so-called Scattered Disk zone never had a close encounter with Neptune, but instead were promoted into these eccentric orbits by Neptune's resonances during the migration epoch. This indicates that the observed Scattered Disk might not be so scattered. This model also produced only a handful of Centaurs, all of which originated at Neptune's mean motion resonances in the Kuiper Belt. We also report estimates of the abundances and masses of the Belt's various subpopulations (e.g., the resonant KBOs, the Main Belt, and the so-called Scattered Disk), and also provide upper limits on the abundance of Centaurs and Neptune's Trojans, as well as upper limits on the sizes and abundances of hypothetical KBOs that might inhabit the a>50 AU zone.Comment: 60 pages, 16 figures. Accepted for publication in the Astronomical Journa

Glycocalyx production in teleosts [Translation from: Verhandlungen der Deutschen Zoologischen Gesellschaft, p.286, 1970]

Shielding the organism against harmful effects from the environment is one of the most important tasks of the outer covering of all animals. The epidermis of primarily aquatic organisms and the epithelia of organs which are exposed to water, such as the digestive or the urinary system, possess a film of glycoproteins and mucopolysaccharides, the glycocalyx. This short paper examines the relationship of the mucus cells with the glycocalyx

Exploring the potential X-ray counterpart of the puzzling TeV gamma-ray source HESS J1507-622 with new Suzaku observations

The unidentified VHE (E>100 GeV) gamma-ray source HESS J1507-622 seems to not fit into standard models for sources related to young supernova remnants, pulsar wind nebulae, or young stellar populations in general. This is due to its intrinsically extended, but yet compact morphology, coupled with a relative large offset (~3.5 deg) from the Galactic plane. Therefore, it has been suggested that this object may be the first representative of a new distinct class of extended off-plane gamma-ray sources. The distance to HESS J1507-622 is the key parameter to constrain the source's most important properties, such as age and energetics of the relativistic particle population. In this article we report on results of follow-up observations of the potential X-ray counterpart with Suzaku. We present detailed measurements of its spectral parameters and find a high absorbing hydrogen column density, compatible with the total amount of Galactic gas in this direction. In comparisons to measurements and models of the Galactic three-dimensional gas distribution we show that the potential X-ray counterpart of HESS J1507-622 may be located at the far end of the Galaxy. If the gamma-ray source is indeed physically connected to this extended X-ray source, this in turn would place the object outside of the usual distribution of Galactic VHE gamma-ray emitters.Comment: 12 pages, 7 figures, accepted for publication by MNRA

Smartphone Wars

None.Technology and Industry

The costs and benefits of regulation : implications for developing countries

The past two decades have seen an unparalleled rise in new health, safety, and environmental regulation in industrial countries. At the same time, insome countries there has been substantial economic deregulation of several industries (including airlines, railroads, trucking, energy, telecommunications, and financial markets). Developing countries are engaged in deregulating some sector of the economy and devising new regulatory frameworks for others. After reviewing the literature, the authors provide an overview of the costs and benefits of regulation throughout the world, highlight the potential gains from reform of regulation and deregulation in both industrial and developing countries, draw lessons from experience with government regulation, and suggest how to improve regulation in developing countries. They find that it is possible to explore systematically the cost and benefits of regulatory activities using standard economic analysis. They conclude that regulation - especially regulation aimed at controlling prices and entry into markets that would otherwise be workably competitive - can limit growth and significantly reduce economic welfare. Although unnecessary process regulation can hurt the economy, social regulations may significantly benefit the average consumer. But some regulations do not meet goals effectively and may sometimes reduce living standards. Developing countries can consider several regulatory policies, tools, and frameworks to improve their approach to regulation. What they choose will depend on available administrative expertise and resources, as well as political constraints and economic impacts. Generally, local and national capabilities for evaluating regulation need to improved. Regulation is not generally undesirable, but it often has undesirable economic consequences, which result in part from political forces to redistribute wealth. These forces can be mitigated by more sharply evaluating in consequences and tradeoffs of proposed regulations.Administrative&Regulatory Law,Environmental Economics&Policies,Economic Theory&Research,Public Sector Economics&Finance,Trade Finance and Investment,Environmental Economics&Policies,Economic Theory&Research,Administrative&Regulatory Law,Public Sector Economics&Finance,Insurance&Risk Mitigation

Why the iPhone Won't Last Forever and What the Government Should Do to Promote its Successor

Because of the overwhelming, positive response to the iPhone as compared to other smart phones, exclusive agreements between handset makers and wireless carriers have come under increasing scrutiny by regulators and lawmakers. In this paper, we document the myriad revolutions that have occurred in the mobile handset market over the past twenty years. Although casual observers have often claimed that a particular innovation was here to stay, they commonly are proven wrong by unforeseen developments in this fast-changing marketplace. We argue that exclusive agreements can play an important role in helping to ensure that another must-have device will soon come along that will supplant the iPhone, and generate large benefits for consumers. These agreements, which encourage risk taking, increase choice, and frequently lower prices, should be applauded by the government. In contrast, government regulation that would require forced sharing of a successful break-through technology is likely to stifle innovation and hurt consumer welfare.

The Costs and Benefits of Regulation: Implications for Developing Countries

The literature on the benefits and costs of regulation demonstrates that this issue can be explored systematically using standard economic analysis. It also shows that regulation can have a significant adverse impact on economic growth. Specifically, regulation aimed at controlling prices and entry into markets that would otherwise be workably competitive is likely to reduce growth and adversely affect the average standard of living. In addition, process regulation can impose a significant cost on the economy. Nonetheless, social regulations may have significant net benefits for the average consumer if designed judiciously. There are several policies developing countries might consider adopting to improve their general approach to regulation. The appropriate regulatory tools and framework will depend on many factors, including bureaucratic expertise, resource availability, political constraints, and economic impacts. There is a general need to enhance the capability for evaluating regulation at the local and national levels.

Interplay between Hbs and bsgamma in the MSSM with Non-Minimal Flavour Violation

We investigate the constraints on flavour-changing neutral heavy Higgs-boson decays H-> b \bar s from b -> s gamma bounds on the flavour-mixing parameters of the MSSM with non-minimal flavour violation (NMFV). In our analysis we include the contributions from the SM and new physics due to general flavour mixing in the squark mass matrices. We study the case of one and two non-zero flavour-mixing parameters and find that in the latter case the interference can raise the Higgs flavour-changing branching ratios by one or two orders of magnitude with respect to previous predictions based on a single non-zero parameter and in agreement with present constraints from $B$ physics. In the course of our work we developed a new "FeynArts" model file for the NMFV MSSM and added the necessary code for the evaluation to "FormCalc". Both extensions are publicly available.Comment: LaTeX2e, 15 pages, 4 figures. Computation improved and figures replaced accordingly. Some references added. Main conclusions remain untouche

The Need for Greater Price Transparency in the Medical Device Industry: An Economic Analysis

Proposed legislation seeks to impose price transparency in the health care industry as a remedy for increasing medical device prices. This paper analyzes previous attempts to mandate similar price-disclosure rules in a variety of industries. We identify the economic conditions under which mandatory price disclosure is likely to generate substantial benefits and costs. Applying these conditions, we conclude that mandatory price disclosure for implantable devices is unlikely to pass a benefit-cost test.

The Economics of “Wireless Net Neutrality”

None.