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A method to approximate derivatives of real functions using complex variables which avoids the subtractive cancellation errors inherent in the classical derivative approximations is described. Numerical examples illustrating the power of the approximation are presented. 1. Overview. A standard method to approximate the derivative of a real valued function F(More)
IMPORTANCE Although vitamin E and memantine have been shown to have beneficial effects in moderately severe Alzheimer disease (AD), evidence is limited in mild to moderate AD. OBJECTIVE To determine if vitamin E (alpha tocopherol), memantine, or both slow progression of mild to moderate AD in patients taking an acetylcholinesterase inhibitor. DESIGN,(More)
BACKGROUND Alzheimer's disease (AD) has been associated with both oxidative stress and excessive glutamate activity. A clinical trial was designed to compare the effectiveness of (i) alpha-tocopherol, a vitamin E antioxidant; (ii) memantine (Namenda), an N-methyl-D-aspartate antagonist; (iii) their combination; and (iv) placebo in delaying clinical(More)
We dedicate this paper (and the rhombus) to Professor Henry Gould on the occasion of his 70th birthday and in appreciation of his work on recurrences such as the rhombus Abstract Pascal's rhombus is a variation of Pascal's triangle in which values are computed as the sum of four terms, rather than two. It is shown that the limiting ratio of the number of(More)
A new international standard, called STEP, is in final draft form. STEP defines a neutral computer readable format for product data exchange, sharing and archiving. STEP deals with all product data throughout the product's life-cycle. In the electronics domain, STEP seeks to harmonize and generalize many of the existing data exchange standards. The STEP(More)
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