197 research outputs found

    A List of the Mayflies (Ephemeroptera) in the Michigan State University Entomology Museum

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    Excerpt: A fairly extensive collection of Epl~emeroptera representing 35 genera, 1 12 determined species and subspecies is preserved in alcohol in the Entomology Museum at Michigan State University, East Lansing, Michigan 48823. Although most of the specimens were collected in Michigan, the collection also contains representatives of many of the common species found in New England and neighboring Canada. A small portion of the collection is not Northeast in origin. This list is designed to aid those interested in the fauna of the Northeast and Great Lakes regions, especially if they need specimens for study. I have included the states or provinces in which specimens were collected, as well as the numbers of individuals; more complete collecting data may be obtained from the author or the museum. Many new state records occur in the collection, and some of these records extend the known range significantly

    A New Species of Thraulodes from New Mexico (Ephemeroptera: Leptophlebiidae)

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    While working on the Ephemeroptera collection in the Entomology Museum at Michigan State University, the author came upon a single specimen of Thraulodes which appeared to be a new species. Although it is only in fair condition (the preserving fluid having dissipated under field conditions), the colors are well preserved and very distinctive. The specimen was sent to Dr. Jay R. Traver, University of Massachusetts, who confirmed suspicions that the specimen was new. I have been informed by Dr. Traver that she and Dr. George F. Edmunds Jr. are presently engaged in a revisionary study of the genus for North and South America, and it should be in press shortly

    Complex Varieties as Minima

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    We will explore various numeric methods of finding roots of an analytic function over some open set of the complex plane. We will discuss a method of visually observing the roots, a gradient descent method for finding the roots of an analytic function, a gradient descent method for solving systems of analytic functions, and finally a method of descent that uses osculating circles to find roots of an analytic function. Of particular interest to this thesis are roots of complex polynomials. There will be examples, code snippets, and outputs of programs to illustrate all of these methods

    Decreased Specific Star Formation Rates in AGN Host Galaxies

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    We investigate the location of an ultra-hard X-ray selected sample of AGN from the Swift Burst Alert Telescope (BAT) catalog with respect to the main sequence (MS) of star-forming galaxies using Herschel-based measurements of the star formation rate (SFR) and stellar mass (\mstar) from Sloan Digital Sky Survey (SDSS) photometry where the AGN contribution has been carefully removed. We construct the MS with galaxies from the Herschel Reference Survey and Herschel Stripe 82 Survey using the exact same methods to measure the SFR and \mstar{} as the Swift/BAT AGN. We find a large fraction of the Swift/BAT AGN lie below the MS indicating decreased specific SFR (sSFR) compared to non-AGN galaxies. The Swift/BAT AGN are then compared to a high-mass galaxy sample (COLD GASS), where we find a similarity between the AGN in COLD GASS and the Swift/BAT AGN. Both samples of AGN lie firmly between star-forming galaxies on the MS and quiescent galaxies far below the MS. However, we find no relationship between the X-ray luminosity and distance from the MS. While the morphological distribution of the BAT AGN is more similar to star-forming galaxies, the sSFR of each morphology is more similar to the COLD GASS AGN. The merger fraction in the BAT AGN is much higher than the COLD GASS AGN and star-forming galaxies and is related to distance from the MS. These results support a model in which bright AGN tend to be in high mass star-forming galaxies in the process of quenching which eventually starves the supermassive black hole itself.Comment: 23 pages, 14 figures, Accepted for publication in MNRAS 2015 June 23. In original form 2015 January 2

    Optical Spectral Properties of Swift BAT Hard X-ray Selected Active Galactic Nuclei Sources

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    The Swift Burst Alert Telescope (BAT) survey of Active Galactic Nuclei (AGN) is providing an unprecedented view of local AGNs ( = 0.03) and their host galaxy properties. In this paper, we present an analysis of the optical spectra of a sample of 64 AGNs from the 9-month survey, detected solely based on their 14-195 keV flux. Our analysis includes both archived spectra from the Sloan Digital Sky Survey and our own observations from the 2.1-m Kitt Peak National Observatory telescope. Among our results, we include line ratio classifications utilizing standard emission line diagnostic plots, [O III] 5007 A luminosities, and H-beta derived black hole masses. As in our X-ray study, we find the type 2 sources to be less luminous (in [O III] 5007 A and 14-195 keV luminosities) with lower accretion rates than the type 1 sources. We find that the optically classified LINERs, H II/composite galaxies, and ambiguous sources have the lowest luminosities, while both broad line and narrow line Seyferts have similar luminosities. From a comparison of the hard X-ray (14-195 keV) and [O III] luminosities, we find that both the observed and extinction-corrected [O III] luminosities are weakly correlated with X-ray luminosity. In a study of the host galaxy properties from both continuum fits and measurements of the stellar absorption indices, we find that the hosts of the narrow line sources have properties consistent with late type galaxies.Comment: 84 pages, 20 figures, 17 tables, accepted in Ap
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