41,768 research outputs found

    Waterfowl Harvest and Hunter Use at Carlyle Lake During the 1972 Season

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    Division of Wildlife Resources Migratory Bird Section, Periodic Report No. 1Report issued on: March 26, 197

    Making the small oblique parameters large

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    We compute the oblique parameters, including the three new parameters V V , W W and X X introduced recently by the Montreal group, for the case of one scalar multiplet of arbitrary weak isospin J J and weak hypercharge Y Y . We show that, when the masses of the heaviest and lightest components of the multiplet remain constant, but J J increases, the oblique parameter U U and the three new oblique parameters increase like J3 J^3 , while T T only increases like J J . For large multiplets with masses not much higher than mZ m_Z , the oblique parameters U U and V V may become much larger than T T and S S .Comment: 9 pages, standard LATEX, 3 figures available from the authors, report CMU-HEP93-17 and DOE-ER/40682-4

    Waterfowl Harvest and Hunter Use at Carlyle Lake During the 1973 Season

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    Division of Wildlife Resources Migratory Bird Section, Periodic Report No. 7Report issued on: April 15, 197

    Imaged sub-stellar companions: not as eccentric as they appear? The effect of an unseen inner mass on derived orbits

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    Increasing numbers of sub-stellar companions are now being discovered via direct imaging. Orbital elements for some of these objects have been derived using star--companion astrometry, and several of these appear to have eccentricities significantly greater than zero. We show that stellar motion caused by an undetected inner body may result in the companion elements derived in such a way being incorrect, which could lead to an overestimation of the eccentricity. The magnitude of this effect is quantified in several regimes and we derive the maximum eccentricity error a third body could introduce in a general form, which may be easily applied to any imaged system. Criteria for identifying systems potentially susceptible to this scenario are presented, and we find that around half of the planets/companion brown dwarfs currently imaged could be liable to these errors when their orbital elements are derived. In particular, this effect could be relevant for systems within 100 pc with companions at >50 AU, if they also harbour an unseen ∼\sim 10 Jupiter mass object at ∼\sim 10 AU. We use the Fomalhaut system as an example and show that a 10% error could be induced on the planet's eccentricity by an observationally allowed inner mass, which is similar in size to the current error from astrometry.Comment: Accepted for publication in MNRA

    Characteristics of Waterfowl Harvest at Horseshoe Lake, Madison County, Illinois

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    Division of Wildlife Resources Migratory Bird Section, Periodic Report No. 13Report issued on: April 21, 197

    Constraining the orbits of sub-stellar companions imaged over short orbital arcs

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    Imaging a star's companion at multiple epochs over a short orbital arc provides only four of the six coordinates required for a unique orbital solution. Probability distributions of possible solutions are commonly generated by Monte Carlo (MCMC) analysis, but these are biased by priors and may not probe the full parameter space. We suggest alternative methods to characterise possible orbits, which compliment the MCMC technique. Firstly the allowed ranges of orbital elements are prior-independent, and we provide means to calculate these ranges without numerical analyses. Hence several interesting constraints (including whether a companion even can be bound, its minimum possible semi-major axis and its minimum eccentricity) may be quickly computed using our relations as soon as orbital motion is detected. We also suggest an alternative to posterior probability distributions as a means to present possible orbital elements, namely contour plots of elements as functions of line of sight coordinates. These plots are prior-independent, readily show degeneracies between elements and allow readers to extract orbital solutions themselves. This approach is particularly useful when there are other constraints on the geometry, for example if a companion's orbit is assumed to be aligned with a disc. As examples we apply our methods to several imaged sub-stellar companions including Fomalhaut b, and for the latter object we show how different origin hypotheses affect its possible orbital solutions. We also examine visual companions of A- and G-type main sequence stars in the Washington Double Star Catalogue, and show that ≳50\gtrsim50 per cent must be unbound.Comment: Accepted for publication in MNRA

    Bending vibrational data accuracy study

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    Computer program for predicting structural bending vibrational dat

    Computing the Loewner driving process of random curves in the half plane

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    We simulate several models of random curves in the half plane and numerically compute their stochastic driving process (as given by the Loewner equation). Our models include models whose scaling limit is the Schramm-Loewner evolution (SLE) and models for which it is not. We study several tests of whether the driving process is Brownian motion. We find that just testing the normality of the process at a fixed time is not effective at determining if the process is Brownian motion. Tests that involve the independence of the increments of Brownian motion are much more effective. We also study the zipper algorithm for numerically computing the driving function of a simple curve. We give an implementation of this algorithm which runs in a time O(N^1.35) rather than the usual O(N^2), where N is the number of points on the curve.Comment: 20 pages, 4 figures. Changes to second version: added new paragraph to conclusion section; improved figures cosmeticall

    Arkansas Cotton Variety Test 2012

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    The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant
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