Growth Conditions and Vitality of Sphagnum in a Tundra Community Along the Alaska Pipeline Haul Road

Effects of road dust and road related construction upon Sphagnum lenense were found in one Sphagnum-rich tundra community along the Alaska Pipeline haul road. Dust, arising from vehicular traffic, settled in greatest quantities near the road with the amount rapidly decreasing away from the road. Water content of Sphagnum lenense in quadrats close to the road and to a buried gasline was generally low when compared with those of S. lenense in more distant quadrats. Total conductivity, pH, and calcium content of water extracted from the Sphagnum was greatest in heavily dust-impacted quadrats. Chlorophyll content (µg chlorophyll a/g dry weight plant tip) was greatest in Sphagnum lenense little exposed to dust and lowest in Sphagnum heavily exposed. Carbon uptake rates in Sphagnum lenense from quadrats far from the road were higher than uptake rates in quadrats near the road, as determined by fixation of 14C labeled CO2

Direction of the oblique medial malleolar osteotomy for exposure of the talus

A medial malleolar osteotomy is often indicated for operative exposure of posteromedial osteochondral defects and fractures of the talus. To obtain a congruent joint surface after refixation, the oblique osteotomy should be directed perpendicularly to the articular surface of the tibia at the intersection between the tibial plafond and medial malleolus. The purpose of this study was to determine this perpendicular direction in relation to the longitudinal tibial axis for use during surgery. Using anteroposterior mortise radiographs and coronal computed tomography (CT) scans of 46 ankles (45 patients) with an osteochondral lesion of the talus, two observers independently measured the intersection angle between the tibial plafond and medial malleolus. The bisector of this angle indicated the osteotomy perpendicular to the tibial articular surface. This osteotomy was measured relative to the longitudinal tibial axis on radiographs. Intraclass correlation coefficients (ICC) were calculated to assess reliability. The mean osteotomy was 57.2 ± 3.2° relative to the tibial plafond on radiographs and 56.5 ± 2.8 on CT scans. This osteotomy corresponded to 30.4 ± 3.7° relative to the longitudinal tibial axis. The intraobserver (ICC, 0.90-0.93) and interobserver (ICC, 0.65-0.91) reliability of these measurements were good to excellent. A medial malleolar osteotomy directed at a mean 30° relative to the tibial axis enters the joint perpendicularly to the tibial cartilage, and will likely result in a congruent joint surface after reductio

Gray matter imaging in multiple sclerosis: what have we learned?

At the early onset of the 20th century, several studies already reported that the gray matter was implicated in the histopathology of multiple sclerosis (MS). However, as white matter pathology long received predominant attention in this disease, and histological staining techniques for detecting myelin in the gray matter were suboptimal, it was not until the beginning of the 21st century that the true extent and importance of gray matter pathology in MS was finally recognized. Gray matter damage was shown to be frequent and extensive, and more pronounced in the progressive disease phases. Several studies subsequently demonstrated that the histopathology of gray matter lesions differs from that of white matter lesions. Unfortunately, imaging of pathology in gray matter structures proved to be difficult, especially when using conventional magnetic resonance imaging (MRI) techniques. However, with the recent introduction of several more advanced MRI techniques, the detection of cortical and subcortical damage in MS has considerably improved. This has important consequences for studying the clinical correlates of gray matter damage. In this review, we provide an overview of what has been learned about imaging of gray matter damage in MS, and offer a brief perspective with regards to future developments in this field

Initial Public Offerings and the Firm Location

The firm geographic location matters in IPOs because investors have a strong preference for newly issued local stocks and provide abnormal demand in local offerings. Using equity holdings data for more than 53,000 households, we show the probability to participate to the stock market and the proportion of the equity wealth is abnormally increasing with the volume of the IPOs inside the investor region. Upon nearly the universe of the 167,515 going public and private domestic manufacturing firms, we provide consistent evidence that the isolated private firms have higher probability to go public, larger IPO underpricing cross-sectional average and volatility, and less pronounced long-run under-performance. Similar but opposite evidence holds for the local concentration of the investor wealth. These effects are economically relevant and robust to local delistings, IPO market timing, agglomeration economies, firm location endogeneity, self-selection bias, and information asymmetries, among others. Findings suggest IPO waves have a strong geographic component, highlight that underwriters significantly under-estimate the local demand component thus leaving unexpected money on the table, and support state-contingent but constant investor propensity for risk

Bid-Ask Spreads, Trading Networks, and the Pricing of Securitizations

The Financial Industry Regulatory Authority began collecting transaction data from broker-dealers in 2011 as a step toward enhancing its understanding of securitization markets. We use transaction data to document the importance of the interdealer network structure to market quality. Some dealers are relatively central in the network and trade with many dealers, while others are peripheral. Core dealers receive relatively lower and less dispersed spreads than peripheral dealers. We develop a model in which core and peripheral dealers trade with different customer clienteles and argue that the presence of relatively sophisticated customers in securitization markets explains these facts

Corporate Tax Reform: Statement of the Financial Economists Roundtable

Corporate tax reform has been a controversial issue in the U.S. for several years, particularly as U.S. companies have accumulated cash in lower‐tax overseas subsidiaries, while some have used “inversions” to establish overseas corporate domiciles. Two features of U.S. corporate taxation stand out: 1. U.S. corporate income tax rates are the highest in the industrialized world. The federal rate is 35%; and, when combined with state taxes, it averages 39%, as compared to an OECD average of 24%. 2. U.S. corporations pay U.S. tax on their worldwide income, but can choose to avoid indefinitely corporate tax on foreign profits by not repatriating them. Neither feature is present in most other Western countries, where the norm is a “territorial” system that taxes companies only on their domestic profits. The Trump administration has proposed to cut U.S. corporate tax rates to 20%, thereby bringing them down to the OECD average, and to adopt a territorial tax regime like those found in most other Western nations. In this statement signed by 31 senior financial economists, the authors recommend cutting U.S. corporate tax rates, but retaining the current system of taxing the worldwide profits of U.S. companies (while giving them credit for taxes paid in overseas jurisdictions). Once U.S. rates drop to the international average, the economists point out, U.S. companies would have much less incentive under the worldwide system to use transfer pricing schemes to shift their profits to low‐tax jurisdictions than under the proposed territorial alternative. Indeed, under the current system, if the lower rates under consideration are enacted, the location of a company's business activity (including the firm's underlying intellectual property) would not affect its taxation. Along with lower corporate tax rates, the economists also recommend that Congress limit or remove the corporate option to defer the taxation of offshore profits and provide a schedule for repatriating off‐shore funds, using the inducement of the now lower rates as well as the possibility of a “tax holiday.