29,031 research outputs found

    On the unlikelihood of specific long range forces in immunologic and enzymatic reactions

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    In the past few years, a great many experiments have been performed by Rothen (24, 25) which he has interpreted as suggesting that antigen and antibody, and enzyme and substrate proteins, can react specifically, although separated by distances of hundreds of angstroms. This hypothesis seems to conflict with evidence accumulated from many other investigations indicating that short range interactions, involving distances usually associated with electrostatic and van der Waals’ forces, and hydrogen bonds, of the order of 5 A, operate in these reactions. We have therefore engaged in a critical analysis of the experimental techniques used by Rothen to determine whether some interpretation other than that invoking the existence of specific long range forces could be found to explain his experimental results

    Laser probing of the atmosphere Semiannual status report

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    Light backscattering experiment in laser probing studies of atmospheric layer above 100 k

    Comments on Ringwood's paper 'Petrogenesis of Apollo 11 basalts and implications for lunar origin'

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    Apollo 11 basalt petrogenesis and theories of lunar evolution comparing lunar and earth environment

    Long distance contributions in D→VγD \to V \gamma decays

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    Using the factorization scheme for the nonleptonic D→VV0D \to V V_0 weak amplitudes, we classify all diagrams which arise in D→VγD \to V \gamma decays and calculate them with the help of the hybrid model which combines the heavy quark effective theory and the chiral Lagrangian approach. Thus we determine the long distance contribution to the amplitudes of Cabibbo allowed and Cabibbo suppressed D→VγD \to V\gamma decays. The calculation of the expected range of the branching ratios of nine different D→VγD \to V \gamma channels is compared with results of other approaches. The present work establishes an increase of the parity violating contribution in these decays in comparison with previous analyses.Comment: 15 pages, latex, 2 figures; we have changed Table 2 and the caption of Table 1. To be published in Eur. Phys.

    Phobos and Deimos: A base for sampling the Martian past

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    Future exploration of Mars is summed up by the proposal that the Martian satellites provide an ideal base for exploring the surface of Mars. For example, a manned base on Deimos could direct a series of unmanned rovers and sample recovery operations, providing an immediate feedback to the operation. Samples analyzed in such an environment would be fresh, and most importantly, would not require quarantine

    Loop algebras, gauge invariants and a new completely integrable system

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    One fruitful motivating principle of much research on the family of integrable systems known as ``Toda lattices'' has been the heuristic assumption that the periodic Toda lattice in an affine Lie algebra is directly analogous to the nonperiodic Toda lattice in a finite-dimensional Lie algebra. This paper shows that the analogy is not perfect. A discrepancy arises because the natural generalization of the structure theory of finite-dimensional simple Lie algebras is not the structure theory of loop algebras but the structure theory of affine Kac-Moody algebras. In this paper we use this natural generalization to construct the natural analog of the nonperiodic Toda lattice. Surprisingly, the result is not the periodic Toda lattice but a new completely integrable system on the periodic Toda lattice phase space. This integrable system is prescribed purely in terms of Lie-theoretic data. The commuting functions are precisely the gauge-invariant functions one obtains by viewing elements of the loop algebra as connections on a bundle over S1S^1
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