5,034 research outputs found
The Magnetization of Carbonaceous Meteorites
Alternating field demagnetization experiments have been conducted on representative samples of the carbonaceous meteorites (carbonaceous chondrites and ureilites). The results indicate that many, if not all, of these meteorites possess an intense and stable magnetic moment of extraterrestrial origin. Thermomagnetic analyses have been conducted on samples of all known carbonaceous meteorites. In addition to yielding quantitative magnetite estimates, these studies indicate the presence of a thermally unstable component, troilite, which reacts with gaseous oxygen to form magnetite. It is proposed that the magnetite found in some carbonaceous chondrites resulted from the oxidation of troilite during the early history of the solar system. The formation of pyrrhotite is expected as a natural consequence of magnetite formation via this reaction. Consideration is given to the implications of magnetite formation on paleointensity studies
Recommended from our members
The Revenue Potential of a Financial Transaction Tax for U.S. Financial Markets
This paper estimates the revenue potential of a financial transaction tax (FTT) for U.S. financial markets. We focus on analyzing the revenue potential of the Inclusive Prosperity Act that was introduced in the U.S. House of Representatives in 2012 and the U.S. Senate in 2015. The tax rates stipulated in this Act include 0.5 percent (50 basis points) for all stock transactions; 0.1 percent (10 basis points) for all bond transactions; and 0.005 percent (0.5 basis points) on the notional value of all derivative trades. We examine three sets of evidence to generate potential revenue estimates: 1) the levels of transaction costs in U.S. financial markets over time and within the range of financial market segments; 2) the extent of trading elasticities under various trading conditions; and 3) the current level of trading activity in U.S. financial markets. Based on this evidence, we conclude that a US FTT operating at the tax rates stated above would generate about 220 billion per year, which equals approximately 1.2 percent of current U.S. GDP. This revenue estimate as a share of GDP is consistent with experiences in other countries that have operated with FTTs with similar tax rates and other design features. It is also consistent with other projections based on tax rates that are comparable to those we are examining. In addition, we examine the 18-fold increase, between the 1970s and the present, in the ratio of stock market trading relative to productive investment spending by U.S. nonfinancial corporations. This sharp rise in stock market trading as a share of productive investments has not been associated with any growth in productive investments themselves. Working from this evidence, we conclude that a U.S. FTT, which should bring a fall in stock market trading relative to productive investment spending, should not, on balance, produce significant negative effects on productive investments
Recommended from our members
Measuring Disease-Free Survival and Cancer Relapse Using Medicare Claims From CALGB Breast Cancer Trial Participants (Companion to 9344)
To determine the accuracy with which Medicare claims data measure disease-free survival in elderly Medicare beneficiaries with cancer, we performed a criterion validation study. We merged gold-standard clinical trial data of 45 elderly patients with node-positive breast cancer who were treated on the Cancer and Leukemia Group B (CAL-GB) adjuvant breast trial 9344 with Centers for Medicare and Medicaid Services (CMS) data files and compared the results of a CMS-based algorithm with the CALGB disease-free survival information to determine sensitivity and specificity. For 5-year disease-free survival, the sensitivity of the CMS-based algorithm was 100% (95% confidence interval [CI] = 81% to 100%), the specificity was 97% (95% CI = 83% to 100%), and the area under the receiver operator curve was 97% (95% CI = 90% to 100%). For 2-year disease-free survival, the test characteristics were less favorable: sensitivity was 83% (95% CI = 36% to 100%), specificity was 95% (95% CI = 83% to 100%), and area under the receiver operator curve was 84% (95% CI = 66% to 100%)
- …