4,385 research outputs found

    Quality and Seasonal Fluctuation of Headwater Streams in Western Montana

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    Paper published as Bulletin 38 in the UM Bulletin Forestry Series.https://scholarworks.umt.edu/umforestrybulletin/1022/thumbnail.jp

    Effects of Mowing Frequency on the Yield and Protein Content of Several Grasses Grown in Pure Stands

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    This paper presents results of a five-year experiment conducted at the Agricultural Experiment Station, Lincoln, Nebraska, on the adaptation, yield, and quality of several grasses subjected to different frequencies of harvest as a means of determining their forage value

    Introduced Forage Grasses for Nebraska

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    This circular presents illustrations, descriptions and recommended usage of fourteen introduced cultivated grasses that are worthy of practical consideration in Nebraska. Most of them can easily be identified by comparing plant specimens with the illustrations and descriptions. This circular has been prepared for use by farmers, county agricultural agents, teachers and others who are interested in our most important grasses. Station Circular 59 contains information and illustrations of the more common native perennial grasses of Nebraska

    Editorial

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    Generalized survival in equilibrium step fluctuations

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    We investigate the dynamics of a generalized survival probability S(t,R)S(t,R) defined with respect to an arbitrary reference level RR (rather than the average) in equilibrium step fluctuations. The exponential decay at large time scales of the generalized survival probability is numerically analyzed. S(t,R)S(t,R) is shown to exhibit simple scaling behavior as a function of system-size LL, sampling time δt\delta t, and the reference level RR. The generalized survival time scale, τs(R)\tau_s(R), associated with S(t,R)S(t,R) is shown to decay exponentially as a function of RR.Comment: 4 pages, 2 figure

    Bostonia. Volume 16

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    Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

    First measurements of the flux integral with the NIST-4 watt balance

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    In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, the gravitational force of an unknown mass is compensated by an electromagnetic force produced by a coil in a magnet system. The electromagnetic force depends on the current in the coil and the magnetic flux integral. Most watt balances feature an additional calibration mode, referred to as velocity mode, which allows one to measure the magnetic flux integral to high precision. In this article we describe first measurements of the flux integral in the new watt balance. We introduce measurement and data analysis techniques to assess the quality of the measurements and the adverse effects of vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum. Meas. This Journal can be found online at http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1

    Diagnosing students' difficulties in learning mathematics

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    This study considers the results of a diagnostic test of student difficulty and contrasts the difference in performance between the lower attaining quartile and the higher quartile. It illustrates a difference in qualitative thinking between those who succeed and those who fail in mathematics, illustrating a theory that those who fail are performing a more difficult type of mathematics (coordinating procedures) than those who succeed (manipulating concepts). Students who have to coordinate or reverse processes in time will encounter far greater difficulty than those who can manipulate symbols in a flexible way. The consequences of such a dichotomy and implications for remediation are then considered

    First-Order Logic Theorem Proving and Model Building via Approximation and Instantiation

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    In this paper we consider first-order logic theorem proving and model building via approximation and instantiation. Given a clause set we propose its approximation into a simplified clause set where satisfiability is decidable. The approximation extends the signature and preserves unsatisfiability: if the simplified clause set is satisfiable in some model, so is the original clause set in the same model interpreted in the original signature. A refutation generated by a decision procedure on the simplified clause set can then either be lifted to a refutation in the original clause set, or it guides a refinement excluding the previously found unliftable refutation. This way the approach is refutationally complete. We do not step-wise lift refutations but conflicting cores, finite unsatisfiable clause sets representing at least one refutation. The approach is dual to many existing approaches in the literature because our approximation preserves unsatisfiability
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