212,360 research outputs found

    Terricolous Spiders (Araneae) of Insecticide-Treated Spruce-Fir Forests in West-Central Maine

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    Spiders of 12 families, 42 genera, and at least 62 species were captured in linear-pitfall traps placed in insecticide-treated (Sevin-4-Oil®, Dipel 4L ®, Thuricide 16B®) and untreated spruce-fIr forests of west-central Maine. Species richness per family ranged from 1 (Theridiidae, Araneidae, Salticidae) to 19 (Erigonidae). Most trapped species were web-spinners (67.2%); most trapped individuals were hunters (75.2%). Lycosidae accounted for 66.1 % of all (n = 887) captured spiders. Total trapped spiders varied among insecticide treatments, sampling dates, and study sites. However, comparison of mean prespray and postspray trap catches indicated no significant reduction (ANOVA, ANCOVA, P 0.05) in terricolous spiders following insecticide treatments. Increases in spider abundance during postspray sampling periods may have masked detection of treatment effects

    A Cubical Flat Torus Theorem and the Bounded Packing Property

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    We prove the bounded packing property for any abelian subgroup of a group acting properly and cocompactly on a CAT(0) cube complex. A main ingredient of the proof is a cubical flat torus theorem. This ingredient is also used to show that central HNN extensions of maximal free-abelian subgroups of compact special groups are virtually special, and to produce various examples of groups that are not cocompactly cubulated.Comment: 14 pages, 2 figures, submitted May 2015 Minor corrections and swapped sections 2 and 3 Corrected an unfortunate typo in Theorem 2.1 - the hypothesis that the cube complex be finite dimensional has now been adde

    Correction to the known distribution of Prionus (Homaesthesis) simplex (Casey) (Coleoptera, Cerambycidae)

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    Prionus (Homaesthesis) simplex (Casey) was described (Casey, 1912:253) from one male specimen from Kansas with no further data. The specimen is in the United States National Museum and is illustrated by Chemsak (1996). Alexander (1958) reported P. simplex from two locations in Craig County, Oklahoma. Alexander's paper appears to be the basis for two localities shown in northeastern Oklahoma on the distribution maps given by Linsley (1962) and Chemsak (1996). The one locality shown in central Kansas on the map by Chemsak (1996) represents just a "state record" and not a specific collecting record (J. Beier!, Editor of Wolfs garden Books, pers. comm.

    Ignorance and Blame

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    Sometimes ignorance is a legitimate excuse for morally wrong behavior, and sometimes it isn’t. If someone has secretly replaced my sugar with arsenic, then I’m blameless for putting arsenic in your tea. But if I put arsenic in your tea because I keep arsenic and sugar jars on the same shelf and don’t label them, then I’m plausibly blameworthy for poisoning you. Why is my ignorance in the first case a legitimate excuse, but my ignorance in the second case isn’t? This essay explores the relationship between ignorance and blameworthiness

    Intraday stock volatility : a New Zealand perspective : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Business in Finance at Massey University

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    Open-to-open, close-to-close, open-to-close (trading) and close-to-open (non-trading) time periods are examined for dually and non-dually listed stocks in an attempt to explain the volatility patterns which were observed in the New Zealand Stock Exchange. The time period analysed covers the 1997 calendar year. The intraday volatility pattern for the New Zealand Stock Exchange showed similar results to previous studies performed on large exchanges around the world. That is, when the return variances are plotted against the trading time they follow a distinct U-shaped curve, caused by high volatility at the opening and closing of the market. Previous studies have found that the high volatility experienced at the opening of the market results from the long non-trading period prior to the opening. This was examined by analysing the open-to-open to close-to-close variance ratio for both dually and non-dually listed stocks. The explanation that the long non-trading period prior to the opening of the market is a major cause of the volatility experienced at the market opening is not supported by the results found in this study. The results obtained from this study show that the high volatility at the market opening is associated with high capitalised stocks. A low open-to-close (trading) to close-to-open (non-trading) variance ratio was observed in the New Zealand market. Previous research has attributed this low ratio to dually listed stocks continuing to trade during the non-trading overnight period of the domestic market. The findings in this study contradict this explanation and suggest that it is low capitalised stocks that are associated with the low trading to non-trading variance ratio observed in the New Zealand Stock Exchange

    Swarm keeping strategies for spacecraft under J2 and atmospheric drag perturbations

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    This thesis presents several new open-loop guidance methods for spacecraft swarms comprised of hundreds to thousands of agents with each spacecraft having modest capabilities. These methods have three main goals: preventing relative drift of the swarm, preventing collisions within the swarm, and minimizing the fuel used throughout the mission. The development of these methods progresses by eliminating drift using the Hill-Clohessy-Wiltshire equations, removing drift due to nonlinearity, and minimizing the J2J_2 drift. In order to verify these guidance methods, a new dynamic model for the relative motion of spacecraft is developed. These dynamics are exact and include the two main disturbances for spacecraft in Low Earth Orbit (LEO), J2J_2 and atmospheric drag. Using this dynamic model, numerical simulations are provided at each step to show the effectiveness of each method and to see where improvements can be made. The main result is a set of initial conditions for each spacecraft in the swarm which provides hundreds of collision-free orbits in the presence of J2J_2. Finally, a multi-burn strategy is developed in order to provide hundreds of collision free orbits under the influence of atmospheric drag. This last method works by enforcing the initial conditions multiple times throughout the mission thereby providing collision free motion for the duration of the mission

    Fourth Amendment Codification and Professor Kerr\u27s Misguided Call for Judicial Deference

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    This essay critiques Professor Orin Kerr\u27s provocative article, The Fourth Amendment and New Technologies: Constitutional Myths and the Case for Caution, 102 Mich. L. Rev. 801 (2004). Increasingly, Fourth Amendment protection is receding from a litany of law enforcement activities, and it is being replaced by federal statutes. Kerr notes these developments and argues that courts should place a thumb on the scale in favor of judicial caution when technology is in flux, and should consider allowing legislatures to provide the primary rules governing law enforcement investigations involving new technologies. Kerr\u27s key contentions are that (1) legislatures create rules that are more comprehensive, balanced, clear, and flexible; (2) legislatures are better able to keep up with technological change; and (3) legislatures are more adept at understanding complex new technologies. I take issue with each of these arguments. Regarding Kerr\u27s first contention, I argue that Congress has created an uneven fabric of protections that is riddled with holes and weak safeguards. Kerr\u27s second contention - that legislatures are better able to update rules quickly as technology shifts - is belied by the historical record, which suggests Congress is actually far worse than the courts in reacting to new technologies. As for Kerr\u27s third contention, shifting to a statutory regime will not eliminate Kerr\u27s concern with judges misunderstanding technology. In fact, many judicial misunderstandings stem from courts trying to fit new technologies into an old statutory regime that is built around old technologies. Therefore, while Kerr is right that our attention must focus more on the statutes, he is wrong in urging for a deferential judicial approach to the Fourth Amendment
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