6,656 research outputs found

    Advanced turboprop vibratory characteristics

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    The assembly of SR5 advanced turboprop blades to develop a structural dynamic data base for swept props is reported. Steady state blade deformation under centrifugal loading and vibratory characteristics of the rotor assembly were measured. Vibration was induced through a system of piezoelectric crystals attached to the blades. Data reduction procedures are used to provide deformation, mode shape, and frequencies of the assembly at predetermined speeds

    The Control of the Apple Curculio by Hogs

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    The apple curculio is causing severe losses in a number of Iowa apple orchards and is not being controlled by spraying. The injury is caused by the feeding of the adult curculios on the fruit. The insect has a long beak with small jaws at the tip with which it chews a hole thru the skin of the apple and hollows out a large cavity below without increasing the size of the opening. This insect shows a peculiar preference for certain varieties, notably the Ben Davis and Delicious, while some varieties such as the Northwestern Greening are practically free from attack

    IMPACT OF LOCALIZED CUTBACKS IN AGRICULTURAL PRODUCTION ON A STATE ECONOMY

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    This study examines the effects that a cutback in production by Texas agricultural producers would have on the economic well-being of all producers and consumers in the stateÂ’s economy. To do this, a quadratic input-output model incorporating econometric estimates of final demand was developed for the Texas economy. The output of the agricultural production sectors was constrained to reflect the cutback in production. The results show that agricultural producers would be economically worse off than before only if the producers of raw agricultural products in Texas imported their input needs from other geographical areas.Community/Rural/Urban Development, Production Economics,

    Monomial transformations of the projective space

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    We prove that, over any field, the dimension of the indeterminacy locus of a rational transformation ff of PnP^n which is defined by monomials of the same degree dd with no common factors is at least (n−2)/2(n-2)/2, provided that the degree of ff as a map is not divisible by dd. This implies upper bounds on the multidegree of ff

    Local unitary invariants for multipartite quantum systems

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    A method is presented to obtain local unitary invariants for multipartite quantum systems consisting of fermions or distinguishable particles. The invariants are organized into infinite families, in particular, the generalization to higher dimensional single particle Hilbert spaces is straightforward. Many well-known invariants and their generalizations are also included.Comment: 13 page

    Stringy K-theory and the Chern character

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    For a finite group G acting on a smooth projective variety X, we construct two new G-equivariant rings: first the stringy K-theory of X, and second the stringy cohomology of X. For a smooth Deligne-Mumford stack Y we also construct a new ring called the full orbifold K-theory of Y. For a global quotient Y=[X/G], the ring of G-invariants of the stringy K-theory of X is a subalgebra of the full orbifold K-theory of the the stack Y and is linearly isomorphic to the ``orbifold K-theory'' of Adem-Ruan (and hence Atiyah-Segal), but carries a different, ``quantum,'' product, which respects the natural group grading. We prove there is a ring isomorphism, the stringy Chern character, from stringy K-theory to stringy cohomology, and a ring homomorphism from full orbifold K-theory to Chen-Ruan orbifold cohomology. These Chern characters satisfy Grothendieck-Riemann-Roch for etale maps. We prove that stringy cohomology is isomorphic to Fantechi and Goettsche's construction. Since our constructions do not use complex curves, stable maps, admissible covers, or moduli spaces, our results simplify the definitions of Fantechi-Goettsche's ring, of Chen-Ruan's orbifold cohomology, and of Abramovich-Graber-Vistoli's orbifold Chow. We conclude by showing that a K-theoretic version of Ruan's Hyper-Kaehler Resolution Conjecture holds for symmetric products. Our results hold both in the algebro-geometric category and in the topological category for equivariant almost complex manifolds.Comment: Exposition improved and additional details provided. To appear in Inventiones Mathematica

    Two generalizations of the PRV conjecture

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    Let G be a complex connected reductive group. The PRV conjecture, which was proved independently by S. Kumar and O. Mathieu in 1989, gives explicit irreducible submodules of the tensor product of two irreducible G-modules. This paper has three aims. First, we simplify the proof of the PRV conjecture, then we generalize it to other branching problems. Finally, we find other irreducible components of the tensor product of two irreducible G-modules that appear for "the same reason" as the PRV ones

    The Reverend Mark Twain: theological burlesque, form, and content

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    (print) 228 p. ; 24 cmI was educated, I was trained, I was a Presbyterian : conformity and critique in Mark Twain's religious dialogue -- Providence don't fire no blank cartridges, boys : God, grotesques, and Sunday-school books in Roughing it -- Mark Twain's hymns in prose : doxology and burlesque in The adventures of Tom Sawyer and Adventures of Huckleberry Finn -- Mark Twain's cruci-fictions : the Second advent as a burlesque life of Christ -- The morphology of martyrdom : fairy tale, epic, and hagiography in Personal recollections of Joan of Arc -- Q: what do Socrates and the shorter catechism have in common? a: dialogic influences on Twain's What is man? -- Prophecy went out with the chicken guts : No. 44, The mysterious stranger, and the christian prophetic traditionItem embargoed for five year

    Strawberry Leaf-roller Control

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    The strawberry leaf-roller is the most serious insect pest on the strawberry in Iowa. It feeds on the plants thruout the summer, increasing in abundance if not controlled, so that the plants may suffer severe injury after the crop has been removed. In the larva or worm stage, the insect feeds between the two halves of a leaf, which is folded along the midrib and fastened together with web. The presence of such leaves in a patch is the best indication of infestation by the leaf-roller. The larvae feed only on one leaf surface, leaving the other intact so that it dries and turns brown
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