22,867 research outputs found

    Telescopes on the Moon or pie in the sky?

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    The question is examined of whether it makes sense to believe that there will one day be an interferometric array of telescopes on the Moon. The question is really one of national commitment to a lunar base, since it is not likely that a scientific undertaking of this magnitude would occur in the absence of permanent human presence on the Moon. A discussion is also given of the real possibility if the exploration of space should be a multinational effort

    New Distribution Records of Michigan Mosquitoes, 1948-1963

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    Excerpt: The following records result from data accumulated from the years 1948-63. A total of more than 175 field samples, usually from different locations, have been taken from 27 counties in the upper and lower peninsulas of Michigan. The total of 2,199 specimens includes 241 larvae, 452 adult males, and 1506 adult females

    A study of the Io-associated plasma and neutral sodium cloud

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    Narrow-band interference filter images were obtained for the Io torus at the S II wavelengths of 6716, 6731 and at the wavelenght of the S III, 9532 spectrum. The purpose of these observations is to study the short term temporal behavior of the torus and to gain a better understanding of the systematic morphology of the torus. From these images, estimates were obtained for the electron and ion densities and ion temperatures as a function of longitude, latitude, radius from Jupiter, and time. From the analysis of images taken in 1983 and 1984, extremely sharp longitudinal variations in plasma density were detected, subcorotational velocities were measures in the torus plasma, the presence of an optical east-west brightness asymmetry was confirmed in the ion emissions, and longitudinal variations were detected in torus ion temperatures

    A hierarchy of parametrizing varieties for representations

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    The primary purpose is to introduce and explore projective varieties, GRASSd(Λ)\text{GRASS}_{\bf d}(\Lambda), parametrizing the full collection of those modules over a finite dimensional algebra Λ\Lambda which have dimension vector d\bf d. These varieties extend the smaller varieties previously studied by the author; namely, the projective varieties encoding those modules with dimension vector d\bf d which, in addition, have a preassigned top or radical layering. Each of the GRASSd(Λ)\text{GRASS}_{\bf d}(\Lambda) is again partitioned by the action of a linear algebraic group, and covered by certain representation-theoretically defined affine subvarieties which are stable under the unipotent radical of the acting group. A special case of the pertinent theorem served as a cornerstone in the work on generic representations by Babson, Thomas, and the author. Moreover, applications are given to the study of degenerations
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