144,251 research outputs found

    A Data Acquisition System (DAS) for marine and ecological research from aerospace technology

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    The efforts of researchers at Mississippi State University to utilize space-age technology in the development of a self-contained, portable data acquisition system for use in marine and ecological research are presented. The compact, lightweight data acquisition system is capable of recording 14 variables in its present configuration and is suitable for use in either a boat, pickup truck, or light aircraft. This system will provide the acquisition of reliable data on the structure of the environment and the effect of man-made and natural activities on the observed phenomenon. Utilizing both self-contained analog recording and a telemetry transmitter for real-time digital readout and recording, the prototype system has undergone extensive testing

    A high excitation HII region in the faint dwarf elliptical galaxy A0951+68

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    We present the results of BVRI imaging and optical spectroscopy of the dwarf galaxy A0951+68. The images reveal that, although this galaxy is classified as a dwarf elliptical, it has some properties that are similar to dwarf irregular galaxies. It contains two bright knots of emission, one of which is red and unresolved and the other blue and resolved. The blue knot also shows a high excitation emission line spectrum. The observed line ratios indicate that this is an HII region, although with some line ratios that are border-line with those in AGN. The emission line luminosity is consistent with ionisation by a single, very luminous O star, or several smaller O stars, but the extended blue light in the knot shows that this has occurred as part of a substantial recent star formation event. We find that the metal abundance, while low compared to typical large galaxies, actually seems to be high for such a low luminosity dwarf. The position of A0951 in the literature is incorrect and we provide the correct value.Comment: 8 pages, Latex, 4 encapsulated postscript figures included, 1 separate JPEG figure; to be published in Monthly Notice

    Are topological defects responsible for the 300 EeV cosmic rays?

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    We use of a hybrid matrix--Monte Carlo method to simulate the cascade through the cosmic background radiation initiated by UHE particles and radiation emitted by topological defects. We follow the cascade over cosmological distances and calculate the intensities of hadrons, gamma-rays and neutrinos produced. We compare our results with the observed cosmic ray intensity at 300 EeV and lower energies, and conclude that topological defects are most unlikely to be the origin of the most energetic cosmic ray events.Comment: 3 pages, compressed and uuencoded PostScript (111kb); Nucl. Phys. B., Proc. Suppl., vol 48, in press (TAUP95 Workshop

    Coupled-cluster single-double calculations of the relativistic energy shifts in C IV, Na I, Mg II, Al III, Si IV, Ca II and Zn II

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    The relativistic coupled-cluster single-double method is used to calculate the dependence of frequencies of strong E1E1-transitions in many monovalent atoms and ions on the fine-structure constant őĪ\alpha. These transitions are used in the search for manifestations of the variation of the fine-structure constant in quasar absorption spectra. Results of the present calculations are in good agreement with previous calculations but are more accurate.Comment: 6 pages, 4 tables, no figures; submitted to Phys. Rev.

    Horizon Report 2009

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    El informe anual Horizon investiga, identifica y clasifica las tecnolog√≠as emergentes que los expertos que lo elaboran prev√©n tendr√°n un impacto en la ense√Īanza aprendizaje, la investigaci√≥n y la producci√≥n creativa en el contexto educativo de la ense√Īanza superior. Tambi√©n estudia las tendencias clave que permiten prever el uso que se har√° de las mismas y los retos que ellos suponen para las aulas. Cada edici√≥n identifica seis tecnolog√≠as o pr√°cticas. Dos cuyo uso se prev√© emerger√° en un futuro inmediato (un a√Īo o menos) dos que emerger√°n a medio plazo (en dos o tres a√Īos) y dos previstas a m√°s largo plazo (5 a√Īos)

    Measures and models for angular correlation and angular-linear correlation

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    Population models for dependence between two angular measurements and for dependence between an angular and a linear observation are proposed. The method of canonical correlations first leads to new population and sample measures of dependence in this latter situation. An example relating wind direction to the level of a pollutant is given. Next, applied to pairs of angular measurements, the method yields previously proposed sample measures in some special cases and a new sample measure in general

    A New Marine Ascomycete from Australia

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    Most marine pyrenomycetes are lignicolous, but some are epiphytic on marine phanerogims and algae. Meyers (1957) listed 30 species of algae known to be attacked by these fungi. A number of reports dealing with marine ascomycetes on algal hosts appeared before 1900, the most noteworthy being those of Winter (1887), and Jones (1898). Cotton (1908) described a pyrenomycete on Ascophyllum nodosum (L.) Le Jol. and summarized previous reports of ascomycetes found on algae. Reed (1902) collected two species, and Sutherland, in a series of papers (1914-1916), reported several alga-infesting pyrenomycetes. More recently, a number of ascomycetes occurring on algae have been noted (Feldmann, 1957, 1958; Cribb & Herbert, 1954; Cribb & Cribb, 1955, 1960a, b; Wilson & Knoyle, 1961; Kohlmeyer, 1963). This report describes a heretofore unreported pyrenomycete collected from the marine alga, Ballia callitricha Ag. The material was obtained from Warrnambool, Victoria, in waters off southern Australia
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