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OBJECTIVES The aim of this study was to determine the constitution of a commercially available root-end filling material, mineral trioxide aggregate, (MTA) (ProRoot MTA, Tulsa Dental, Tulsa, OK, USA). The surface morphology of the material with various treatment conditions was also evaluated. METHODS The constitution of two commercial versions of MTA was(More)
Ribonuclease A (RNase A) catalyzes the cleavage of RNA after pyrimidine nucleotides. When bound in the active site, the base of a pyrimidine nucleotide forms hydrogen bonds with the side chain of Thr45. Here, the role of Thr45 was probed by using the wild-type enzyme, its T45G variant, X-ray diffraction analysis, and synthetic oligonucleotides as ligands(More)
Discussion papers are research materials circulated by their authors for purposes of information and discussion. They have not necessarily undergone formal peer review. Abstract Federal policies intended to slow global warming would impose potentially significant costs on households, and the costs would vary depending on the policy approach used. This paper(More)
The introduction of the U.S. SO 2 allowance-trading program to address the threat of acid rain as part of the Clean Air Act Amendments of 1990 is a landmark event in the history of environmental regulation. The program was a great success by almost all measures. This paper, which draws upon a research workshop and a policy roundtable held at Harvard in May(More)
Discussion papers are research materials circulated by their authors for purposes of information and discussion. They have not necessarily undergone formal peer review. Abstract This paper evaluates the costs to households of a carbon dioxide (CO 2) cap-and-trade program. We find important variation in the distribution of costs of the policy across 11(More)
A simple vortex adapter (like that available from Sigma) could aid in processing many samples simultaneously. The time required for the whole process, from picking up the colony for lysis to visualization of the amplified product on agarose gel, is only about 4 h, saving time in routine analysis of mycobacteria. We found that this method yields genomic DNA(More)
of Management are gratefully acknowledged. Abstract This paper shows that a ratio of share prices to GDP (output in the economy) tracks a large fraction of the variation over time in expected returns from the aggregate stock market. In particular, the price-output ratio captures considerably more of the variation in returns than do price-earnings and(More)
We examine the in-and out-of-sample behavior of two popular trading systems, Alexander and Double MA filters, for fourteen developed-country currencies using daily data with bid-ask spreads. We find significant in-sample returns in the early periods. But out-of-sample returns are lower and only occasionally significant. We show that a currency risk factor(More)