4,070 research outputs found

    Martian atmospheric compositional analysis- its biological significance first quarterly progress report, 15 may - 15 aug. 1965

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    Biological significance of Martian atmospheric compositional analysis, and life detection studies of chemical free energy in surface matte

    Continuation of studies in statistical decision theory in large scale biological experiments Final report, 1 May 1965 - 31 Jul. 1966

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    Statistical decision theory applied to Martian atmosphere analysis, life detection experiments, and gas chromatogram measurements of n-alkane distributions in material

    Statistical decision problems in large scale biological experiments Final report

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    Statistical decision theory applied to problems associated with Martian biological exploration progra

    Crossword Puzzle Letter Frequencies

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    In 500 crossword puzzles syndicated by the Newspaper Enterprise Association, and published in the Laramie Daily Boomerang six days a week between October 24, 1976 and June 11, 1978 (about 20 consecutive months), the number of times each letter of the alphabet was used was tabulated. The statistical results are summarized in the table on the next page, and discussed in more detail below

    Dual Geometric Worm Algorithm for Two-Dimensional Discrete Classical Lattice Models

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    We present a dual geometrical worm algorithm for two-dimensional Ising models. The existence of such dual algorithms was first pointed out by Prokof'ev and Svistunov \cite{ProkofevClassical}. The algorithm is defined on the dual lattice and is formulated in terms of bond-variables and can therefore be generalized to other two-dimensional models that can be formulated in terms of bond-variables. We also discuss two related algorithms formulated on the direct lattice, applicable in any dimension. These latter algorithms turn out to be less efficient but of considerable intrinsic interest. We show how such algorithms quite generally can be "directed" by minimizing the probability for the worms to erase themselves. Explicit proofs of detailed balance are given for all the algorithms. In terms of computational efficiency the dual geometrical worm algorithm is comparable to well known cluster algorithms such as the Swendsen-Wang and Wolff algorithms, however, it is quite different in structure and allows for a very simple and efficient implementation. The dual algorithm also allows for a very elegant way of calculating the domain wall free energy.Comment: 12 pages, 6 figures, Revtex

    Dissipative Transport of a Bose-Einstein Condensate

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    We investigate the effects of impurities, either correlated disorder or a single Gaussian defect, on the collective dipole motion of a Bose-Einstein condensate of 7^7Li in an optical trap. We find that this motion is damped at a rate dependent on the impurity strength, condensate center-of-mass velocity, and interatomic interactions. Damping in the Thomas-Fermi regime depends universally on the disordered potential strength scaled to the condensate chemical potential and the condensate velocity scaled to the peak speed of sound. The damping rate is comparatively small in the weakly interacting regime, and the damping in this case is accompanied by strong condensate fragmentation. \textit{In situ} and time-of-flight images of the atomic cloud provide evidence that this fragmentation is driven by dark soliton formation.Comment: 14 pages, 20 figure

    Phase Coherence and Superfluid-Insulator Transition in a Disordered Bose-Einstein Condensate

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    We have studied the effects of a disordered optical potential on the transport and phase coherence of a Bose-Einstein condensate (BEC) of 7Li atoms. At moderate disorder strengths (V_D), we observe inhibited transport and damping of dipole excitations, while in time-of-flight images, random but reproducible interference patterns are observed. In-situ images reveal that the appearance of interference is correlated with density modulation, without complete fragmentation. At higher V_D, the interference contrast diminishes as the BEC fragments into multiple pieces with little phase coherence.Comment: 4 pages, 5 figures, distortions in figures 1 and 4 have been fixed in version 3. This paper has been accepted to PR

    A Last Message From Our Deans

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