5,893 research outputs found
Common subbundles and intersections of divisors
Let V_0 and V_1 be complex vector bundles over a space X. We use the theory
of divisors on formal groups to give obstructions in generalised cohomology
that vanish when V_0 and V_1 can be embedded in a bundle U in such a way that
V_0\cap V_1 has dimension at least k everywhere. We study various algebraic
universal examples related to this question, and show that they arise from the
generalised cohomology of corresponding topological universal examples. This
extends and reinterprets earlier work on degeneracy classes in ordinary
cohomology or intersection theory.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-42.abs.htm
Judicially Compelled Disclosure of Researchers’ Data: A Judge’s View
Crabb looks at the approach one court has established to balance the demands of the legal system with the legitimate concerns of researchers
Obstruction theory on 8-manifolds
This note gives a uniform, self-contained, and fairly direct approach to a
variety of obstruction-theoretic problems on 8-manifolds. We give necessary and
sufficient cohomological critera for the existence of almost complex and almost
quaternionic structures on the tangent bundle and for the reduction of the
structure group to U(3) by the homomorphism U(3) --> O(8) given by the Lie
algebra representation of PU(3).Comment: 19 page
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Bait preference field study for the California ground squirrel
A bait preference field study of the California ground squirrel (Spermophilus beecheyi beecheyi) was performed involving the comparison of the following untreated bait formulations fed ad lib: oat groats, Ramik Green, and ZP Rodent Ag Bait. The study was performed on rangeland at California Polytechnic State University, San Luis Obispo, California, from March 11, 1984, to September 15, 1984. Poor bait quality problems occurred in the early period of the study (March 11 to May 17), resulting in poor acceptance of both Ramik and Ag Bait. A descriptive analysis of this period is discussed. The statistical analysis of relative bait consumption (June 3 to September 15) determined a significant difference between the consumption of oat groats versus Ramik and Ag Bait; no significant difference between Ramik and Ag Bait; the acceptance of all three baits was good; and the use of any of the three would result in control of the ground squirrels. There was a strong correlation between overall bait consumption and the ground squirrels observed
High Rate Neutrino Detectors for Neutrino Factories
Three types of high rate neutrino detectors for neutrino interaction physics
at neutrino factories are discussed. High performance general-purpose detectors
might collect event samples on the order of a billion events or more. This
could greatly improve on existing analyses of neutrino interactions and also
lead to new and important analysis topics including, for example, precise
determinations of the CKM matrix elements |Vub| and |Vcb|. The potential of
such general purpose detectors is illustrated with reference to a detector,
presented previously in reference hep-ex/9907033, that is structured around a
novel and compact vertexing and tracking neutrino target comprising a stack of
CCD pixel devices. Design ideas and prospects are also discussed for two types
of specialized detectors: (i) polarized targets filled with polarized solid
protium-deuterium (HD), for unique and powerful studies of the nucleon's spin
structure, and (ii) Fully active liquid tracking targets with masses of several
tonnes for precise determinations of the weak mixing angle, from the total
cross-section for neutrino-electron scattering. All three detector types pose
severe technical challenges but their utilization could add significantly to
the physics motivation for neutrino factories.Comment: 12 pages, 1 figure. Submitted to Proc. ICFA/ECFA Workshop "Neutrino
Factories based on Muon Storage Rings" (nuFACT'99), Lyon, France, 5--9 July,
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The extremal algebra on two hermitians with square 1
Let Ea(u,v) be the extremal algebra determined by two hermitians u and v with u2 = v2 = 1. We show that: Ea(u,v) = {f=gu:f,g ε C(T)}, where T is the unit circle; Ea(u,v) is C*-equivelant to C*(G), where G is the infinite dihedral group; most of the hermitian elements k od Ea(u,v) have the property that kn is hermitian for all odd n but for no even n; any two hermitian words in G generate an isometric copy of Ea(u,v) in Ea(u,v)
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