45 research outputs found

    Difficulties in Complex Multiplication and Exponentiation

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    During my study of the iteration of functions of the form f(z)=zα+cf(z)=z^{\alpha}+c, where z,c \in \mathbbC, and α\alpha is a rational non-integer larger than 2 (\cite{s1}), I encountered a fundamental difficulty in the exponentiation of a complex number. This paper will explore this difficulty and the problems encountered in trying to resolve it using a Riemann surface which is the direct generalization of the polar form of the complex plane. This paper will also answer two questions raised by Robert Corless in his \emph{E.C.C.A.D.} presentation \cite{co}: "Can a Riemann surface variable be coded? What will the operations be on it?" Unfortunately, the addition operation will be incompatible with the Riemann surface structure.Comment: 17 pages, 9 figures (.ps format

    Material interactions of the operational SNAP-9A generator

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    The design of the SNAP-9A generator includes a number of different materials in intimate contact. The possible interactions among the materials and their effect on the postulated re-entry breakup sequence of the generator are discussed. Experimental evidence obtained under static vacuum conditions for all of the interactions possible is presented. (auth

    Second Generation of Antisense Oligonucleotides: From Nuclease Resistance to Biological Efficacy in Animals

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    From efforts to improve the biophysical properties of antisense oligonucleotides by incorporating backbone- or sugar-modified nucleoside analogs, 2'-O-methoxyethyl ribonucleosides 8b were identified as building blocks for a second generation of antisense oligonucleotides. Compounds containing these modifications were demonstrated to combine the benefit of a high binding affinity to the RNA complement with a large increase in nuclease resistance, allowing the use of regular phosphodiester linkages. Chimeric oligonucleotides with 2'-O-methoxyethyl ribonucleosides, 8b, in the wings and a central DNA-phosphorothioate window were shown to efficiently downregulate C-'raf' kinase and PKC-α messenger-RNA in tumor cell lines resulting in a profound inhibition of cell proliferation. The same compounds were able to effectively reduce the growth of tumors in animal models at low concentrations indicating the potential utility of these second generation antisense oligonucleotides for therapeutic applications

    A perfectly symmetric lac operator binds the lac repressor very tightly.

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    Operant conditioning of a small-scale muscle response

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    Six naive male subjects were reinforced for responses in the 20-30 microvolt range, and two each for those in 10-20 and 30-40 microvolt ranges. Records were taken of 15 min of “settling down,” 15 min of initial operant level responding, 30 min of conditioning, and 45 min of extinction, 30 min with light present and 15 min without. The results were: (1) small-scale muscle potentials from the thenar eminence, in the 10-20, 20-30, and 30-40 microvolt ranges, were conditioned, using pointer movement as the reinforcement; (2) the response rate in adjacent ranges of greater and lesser amplitude also increased during such conditioning and decreased during the subsequent extinction; (3) during conditioning the frequency of response distribution shifted toward the reinforced range; (4) subjects were unaware of the reinforced response; (5) observing a noncontingent moving pointer increased the response rate in the 20-30 microvolt range, but did not lead to conditioning
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