6,028 research outputs found

    On (2,3)-agreeable Box Societies

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    The notion of (k,m)(k,m)-agreeable society was introduced by Deborah Berg et al.: a family of convex subsets of Rd\R^d is called (k,m)(k,m)-agreeable if any subfamily of size mm contains at least one non-empty kk-fold intersection. In that paper, the (k,m)(k,m)-agreeability of a convex family was shown to imply the existence of a subfamily of size βn\beta n with non-empty intersection, where nn is the size of the original family and β[0,1]\beta\in[0,1] is an explicit constant depending only on k,mk,m and dd. The quantity β(k,m,d)\beta(k,m,d) is called the minimal \emph{agreement proportion} for a (k,m)(k,m)-agreeable family in Rd\R^d. If we only assume that the sets are convex, simple examples show that β=0\beta=0 for (k,m)(k,m)-agreeable families in Rd\R^d where k<dk<d. In this paper, we introduce new techniques to find positive lower bounds when restricting our attention to families of dd-boxes, i.e. cuboids with sides parallel to the coordinates hyperplanes. We derive explicit formulas for the first non-trivial case: the case of (2,3)(2,3)-agreeable families of dd-boxes with d2d\geq 2.Comment: 15 pages, 10 figure

    Cell biology, SevERing mitochondria

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    The endoplasmic reticulum is an active participant in the division of another organelle, the mitochondrion

    Investigation of thermodynamic mechanisms for the production of compounds essential for the origin of life First quarter technical report, Oct. 1 - Dec. 31, 1965

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    Expected thermodynamic equilibrium composition calculated for atmospheres of Earth, Venus, Mars, and Jupite

    Characterization of causes of signal phase and frequency instability Final report

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    Characteristic instabilities in phase and frequency errors of reference oscillator

    Evaluation of the hazard from exposure to electron irradiation simulating that in the synchronous orbit

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    The electron spectrum predicted for the synchronous orbit was simulated to determine the effects that might occur to astroscientists exposed to such irradiation while on a prolonged space station mission in that region. Miniature pigs were exposed to monoenergetic and spectral-fractionated irradiations with 0.5 to 2.1 MeV electrons. Clinical and pathological alterations observed in biopsies were correlated with depth-dose pattern and length of post irradiation period up to one year. With monoenergetic electrons, the lowest dose causing a recognizable lesion was 1450 rad and with increasing dose lesions appeared earlier and were more severe. At the highest dose given, 2650 rad, ulceration extending into the dermis was present by twenty one days and required about four months for complete healing. Spectral-fractionated irradiations, in which the total dose range was essentially comparable to that of the monoenergetic series, resulted in very minimal outer dermis edema at 1790 rad and at no dose employed did necrosis of epidermis or ulceration into dermis occur

    Planar ion trap (retarding potential analyzer) experiment for atmosphere explorer

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    The retarding potential analyzer and drift meter were carried aboard all three Atmosphere Explorer spacecraft. These instruments measure the total thermal ion concentration and temperature, the bulk thermal ion velocity vector and some limited properties of the relative abundance of H(+), He(+), O(+) and molecular ions. These instruments functioned with no internal failures on all the spacecraft. On AE-E there existed some evidence for external surface contamination that damaged the integrity of the RPA sweep grids. This led to some difficulties in data reduction and interpretation that did not prove to be a disastrous problem. The AE-D spacecraft functioned for only a few months before it re-entered. During this time the satellite suffered from a nutation about the spin axis of about + or - 2 deg. This 2 deg modulation was superimposed upon the ion drift meter horizontal ion arrival angle output requiring the employment of filtering techniques to retrieve the real data

    Experimental Studies Concerning Equilibrium and Non-equilibrium Systems in Pre-biological Atmospheres Progress Report, Sep. 1, 1965 - Mar. 1, 1966

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    High energy radio frequency plasma discharge reactor designed for experiments to study equilibrium and nonequilibrium systems in pre-biological atmospher

    Investigation of thermodynamic mechanisms for the production of complex compounds essential for the origin of life Final report, 1 Oct. 1965 - 30 Sep. 1966

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    Thermodynamic equilibria in planetary atmospheres and in origin of organic matter - determination of amino acid pairing and sequences in protein

    The Design of a Morse-To-Teletype Signal Converter Using Intergrated Micrologic Circuitry.

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    This paper investigates the use of a Morse to teletype signal converter with existing teletype equipment to continuously monitor and display received Morse signals. This device would greatly reduce operator fatigue and provide increased efficiency. Important aspects of the converter design problem are presented and different approaches to the problems encountered in this design are developed. A micrologic digital design is presented and its operation discussed. Although not fully implemented, it is considered far superior to other methods of implementation. It will accept Morse keyed audio signals in the 300-3000 hz. range at keying speeds of 10 to 100 words per minute and convert them to teletype code.http://archive.org/details/thedesignofmorse1094540077Lieutenant, United States NavyApproved for public release; distribution is unlimited

    Calibration of liquid argon and neon detectors with 83Krm^{83}Kr^m

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    We report results from tests of 83^{83}Krm^{\mathrm{m}}, as a calibration source in liquid argon and liquid neon. 83^{83}Krm^{\mathrm{m}} atoms are produced in the decay of 83^{83}Rb, and a clear 83^{83}Krm^{\mathrm{m}} scintillation peak at 41.5 keV appears in both liquids when filling our detector through a piece of zeolite coated with 83^{83}Rb. Based on this scintillation peak, we observe 6.0 photoelectrons/keV in liquid argon with a resolution of 6% (σ\sigma/E) and 3.0 photoelectrons/keV in liquid neon with a resolution of 19% (σ\sigma/E). The observed peak intensity subsequently decays with the 83^{83}Krm^{\mathrm{m}} half-life after stopping the fill, and we find evidence that the spatial location of 83^{83}Krm^{\mathrm{m}} atoms in the chamber can be resolved. 83^{83}Krm^{\mathrm{m}} will be a useful calibration source for liquid argon and neon dark matter and solar neutrino detectors.Comment: 7 pages, 12 figure
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