Heteroskedasticity-Robust Inference in Finite Samples

Since the advent of heteroskedasticity-robust standard errors, several papers have proposed adjustments to the original White formulation. We replicate earlier findings that each of these adjusted estimators performs quite poorly in finite samples. We propose a class of alternative heteroskedasticity-robust tests of linear hypotheses based on an Edgeworth expansions of the test statistic distribution. Our preferred test outperforms existing methods in both size and power for low, moderate, and severe levels of heteroskedasticity.

Adipogenesis in fetal pig subcutaneous adipose tissue: remarkable developmental features before the onset of adipogenesis

The collection of investigations indicating the importance of adipose tissue architecture to vasculogenesis and angiogenesis during adipogenesis is reviewed. Early in development of the architecture vascular structure develops before overt adipocyte differentiation. Adipocyte development and the expanding and elaborating vascularity are closely linked during adipocyte cluster growth. Furthermore, fetal adipose tissue studies show that location-dependent angiogenic potential ranges from more to less in regards to the extent of endothelial cells and developing arterioles present before overt adipogenesis. Fetal adipose tissue cells express and secrete numerous factors that may initiate the development of adipose tissue architecture and associated developmental gradients. Possibly, the neural connection between hypothalamic neurons and adipose tissue represents part of a regulatory pathway between the hypothalamus and adipose tissue development via neural driven patterns of blood vessel development. Finally, small blood vessels in fetal adipose tissue may phagocytose and metabolize circulating lipids in the absence of differentiated adipocytes. Therefore, several aspects of the stromal and vascular components of adipose tissue may play critical roles in the timing and distribution of developing adipose tissue.Adipobiology 2012; 4: 23-32

Entry in the ADHD drugs market: Welfare impact of generics and me-toos

Recent decades have seen a growth in treatments for attention deficit hyperactivity disorder (ADHD) including many branded and generic drugs. In the early 2000's, new drug entry dramatically altered market shares. We estimate a demand system for ADHD drugs and assess the welfare impact of new drugs. We find that entry induced large welfare gains by reducing prices of substitute drugs, and by providing alternative delivery mechanisms for existing molecules. Our results suggest that the success of follow-on patented drugs may come from unanticipated innovations like delivery mechanisms, a factor ignored by proposals to retard new follow-on drug approvals

Active flutter control for flexible vehicles, volume 1

An active flutter control methodology based on linear quadratic gaussian theory and its application to the control of a super critical wing is presented. Results of control surface and sensor position optimization are discussed. Both frequency response matching and residualization used to obtain practical flutter controllers are examined. The development of algorithms and computer programs for flutter modeling and active control design procedures is reported

Shanghai Honeymoon

Sheet music includes Asian stereotypes, cultural appropriation, bigoted language, and/or imagry. With Ukulele arrangement. Contains advertisements and/or short musical examples of pieces being sold by publisher.https://digitalcommons.library.umaine.edu/mmb-vp/6996/thumbnail.jp

Are Regulators Forward-Looking? The Market Price of Copper Versus the Regulated Price of Mandatory Access to Unbundled Local Loops in Telecommunications Networks

The Enduring Lessons of the Breakup of AT&T: A Twenty-Five Year Retrospective. \u27 Conference held at the University of Pennsylvania Law School on April 18-19, 2008. Around the world, since 1996, regulators have mandated that incumbent local exchange carriers (ILECs) offer competitors access to their network at regulated prices that reflect forward-looking cost. Regulated prices for unbundled network elements are based on total element long-run incremental cost (TELRIC), which in turn is calculated using engineering models that estimate the costs of a hypothetical carrier employing the most efficient telecommunications technology currently available and the lowest cost network configuration, given the existing location of the ILEC\u27s actual wire centers. These cost models require detailed estimates of the equipment and installation prices of the numerous components that are used in a telecommunications network. When there is uncertainty about how these prices will change over the period for which costs and prices are required, the resulting cost estimates used for setting the regulated prices of unbundled network elements can be very inaccurate. Similarly, when regulators in other jurisdictions are considering such rates as benchmarks, it is necessary to make adjustments to account for such large differences in critical input prices, so that the benchmark rates will be representative of the costs that actually will be incurred by efficient carriers offering unbundled elements in those jurisdictions. The precipitous rise in the price of copper since 2003 exemplifies this need to reevaluate the inputs used by regulators in their cost model, as well as the inferences drawn from those models. These increases differ from the type of constant annual expected input price growth (or decline) situation that some cost models used outside the United States have accommodated with tilted annuity methods. Rather than a gradual anticipated price increase, copper prices escalated rapidly and are likely to remain well above the levels that regulators used to set existing loop rates. Accounting for such evidence would change the forward-looking costs of a hypothetically efficient ILEC network that one of the most prominent U.S. state regulatory commissions--the California Public Utilities Commission (CPUC)--established in 2006. Similarly, in 2007, the Commerce Commission in New Zealand employed a benchmarking methodology for the pricing of unbundled loops that failed to account for the increased price of copper. A global trend may be emerging among telecommunications regulators to ignore the input requirements of their own forward-looking cost models. Such a trend would be consistent with a version of regulatory opportunism in which regulators are forward-looking only when doing so produces lower regulated prices over time. The risk of regulatory opportunism and the high price of copper together create a strong incentive for an ILEC to replace its copper loops with optical fiber. Although some CLECS could be adversely affected by such a decommissioning of copper loops, an ILEC has no duty under U.S. antitrust or telecommunications law to keep copper loops in service for the benefit of its competitors