4,416 research outputs found

    Native and Introduced Forage Plants

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    The true grasses are one of the most valuable families of plants. To them belong the small grains (oats, wheat, barley, etc.,), corn, the various sorts of cane, the great bamboo of Asia, and a host of other plants of more or Jess importance to man or beast. In the great prairie regions of the United States the grasses form by far the greater part of the natural vegetation and constitute one of the most valuable of the natural resources as well. In our own state of South Dakota stock-raising- has been one of the leading industries ever since its settlement, and will continue to be so for years to come. The state, as a whole, is peculiarly well adapted to stock-raising and dairying. One of the most important elements in this fitness is the great richness of the grass flora and of the native species in particular. About one hundred and sixty species of grasses are known to grow within the limits of the state. Of these, about one hundred and five are native to the soil, the remainder being found either under cultivation or introduced some other way. Some of them are weeds, but the majority are more or less useful as forage plants

    Birds and beaches, dogs and leashes : dog owners\u27 sense of obligation to leash dogs on beaches in Victoria, Australia

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    Domesticated dogs threaten the conservation of beach-nesting birds in Australia through disturbance, and destruction of eggs and chicks. Leashing of dogs can improve conservation outcomes, but few dogs are leashed on beaches. We surveyed dog owners to explore their sense of obligation to leash dogs on beaches. Dog owners were more likely to feel obliged to leash their dog when they believed other people expected dogs to be leashed, and when they believed their dog was a threat to wildlife or people. Dog owners were less likely to feel obliged to leash their dog if they considered unleashed dog recreation to be important. Improved compliance may be achieved through community-based approaches to foster social norms for dog control, tailoring information products to emphasize the risk that all unleashed dogs may pose to beach-nesting birds and raising awareness of designated off-leash exercise dog recreation areas. <br /

    The effects of turbulence intensity on the downstream performance of horizontal axis tidal stream turbines

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    This study focuses on a comparison of model results from a blade element momen- tum computational fluid dynamics (BEM-CFD) steady state RANS model, and a BEMT model that accounts for the wake generated from upstream turbines using analytic expressions. Rotor forces are calculated using 3D hydrofoil profile data. Both techniques are validated against ex- isting experimental data, and then used to assess the power extraction of downstream turbines. Turbulent inflow conditions of 3% and 7% are applied, and the results of power extraction as- sessed. Particular attention is paid to the velocity field, with respect to the downstream wake, to assess how the turbulence characteristics effect the recovery rate and downstream power potential. Both models highlight the different recovery rates of the two turbulent conditions

    The response to high magnetic fields of the vacuum phototriodes for the compact muon solenoid endcap electromagnetic calorimeter

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    The endcap electromagnetic calorimeter of the Compact Muon Solenoid (CMS) detects particles with the dense fast scintillator lead tungstate (PbWO4). Due to the low light yield of this scintillator photodetectors with internal gain are required. Silicon avalanche photodiodes cannot be used in the endcap region due to the intense neutron flux. Following an extensive R&D programme 26 mm diameter single-stage photomultipliers (vacuum phototriodes) have been chosen as the photodetector in the endcap region. The first 1400 production devices are currently being evaluated following recent tests of a pre-production batch of 500 tubes. Tubes passing our acceptance tests have responses, averaged over the angular acceptance of the endcap calorimeter, corresponding to the range 20 to 55 electrons per MeV deposited in PbWO4. These phototriodes operate, with a typical gain of 10, in magnetic fields up to 4T.PPARC, EC(INTAS-CERN scheme 99-424

    Cartan subalgebras in C*-algebras of Hausdorff etale groupoids

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    The reduced CC^*-algebra of the interior of the isotropy in any Hausdorff \'etale groupoid GG embeds as a CC^*-subalgebra MM of the reduced CC^*-algebra of GG. We prove that the set of pure states of MM with unique extension is dense, and deduce that any representation of the reduced CC^*-algebra of GG that is injective on MM is faithful. We prove that there is a conditional expectation from the reduced CC^*-algebra of GG onto MM if and only if the interior of the isotropy in GG is closed. Using this, we prove that when the interior of the isotropy is abelian and closed, MM is a Cartan subalgebra. We prove that for a large class of groupoids GG with abelian isotropy---including all Deaconu--Renault groupoids associated to discrete abelian groups---MM is a maximal abelian subalgebra. In the specific case of kk-graph groupoids, we deduce that MM is always maximal abelian, but show by example that it is not always Cartan.Comment: 14 pages. v2: Theorem 3.1 in v1 incorrect (thanks to A. Kumjain for pointing out the error); v2 shows there is a conditional expectation onto MM iff the interior of the isotropy is closed. v3: Material (including some theorem statements) rearranged and shortened. Lemma~3.5 of v2 removed. This version published in Integral Equations and Operator Theor

    Immediate reward reinforcement learning for clustering and topology preserving mappings

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    We extend a reinforcement learning algorithm which has previously been shown to cluster data. Our extension involves creating an underlying latent space with some pre-defined structure which enables us to create a topology preserving mapping. We investigate different forms of the reward function, all of which are created with the intent of merging local and global information, thus avoiding one of the major difficulties with e.g. K-means which is its convergence to local optima depending on the initial values of its parameters. We also show that the method is quite general and can be used with the recently developed method of stochastic weight reinforcement learning [14]

    Graph Treewidth and Geometric Thickness Parameters

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    Consider a drawing of a graph GG in the plane such that crossing edges are coloured differently. The minimum number of colours, taken over all drawings of GG, is the classical graph parameter "thickness". By restricting the edges to be straight, we obtain the "geometric thickness". By further restricting the vertices to be in convex position, we obtain the "book thickness". This paper studies the relationship between these parameters and treewidth. Our first main result states that for graphs of treewidth kk, the maximum thickness and the maximum geometric thickness both equal k/2\lceil{k/2}\rceil. This says that the lower bound for thickness can be matched by an upper bound, even in the more restrictive geometric setting. Our second main result states that for graphs of treewidth kk, the maximum book thickness equals kk if k2k \leq 2 and equals k+1k+1 if k3k \geq 3. This refutes a conjecture of Ganley and Heath [Discrete Appl. Math. 109(3):215-221, 2001]. Analogous results are proved for outerthickness, arboricity, and star-arboricity.Comment: A preliminary version of this paper appeared in the "Proceedings of the 13th International Symposium on Graph Drawing" (GD '05), Lecture Notes in Computer Science 3843:129-140, Springer, 2006. The full version was published in Discrete & Computational Geometry 37(4):641-670, 2007. That version contained a false conjecture, which is corrected on page 26 of this versio

    Characterization of skeletal phenotypes of TRα1(PV) and TRβ(PV) mutant mice: implications for tissue thyroid status and T3 target gene expression

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    Bone development is extremely sensitive to alterations in thyroid status. Recently, we analyzed the skeletal phenotypes of mice with the dominant negative resistance to thyroid hormone (RTH) mutation PV targeted to either the thyroid hormone receptor (TR) α1 or β gene. This perspective summarizes our findings to date and explores the wider implications for thyroid status and T3 target gene expression in individual tissues

    Measurement of Fluorescence Phenomena from Yttrium and Gadolinium Oxysulfide Phosphors using a 45-MeV Proton Beam

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478
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