10,350 research outputs found

    New Michigan Tick (Acari: Ixodidae) and Flea (Siphonaptera: Ceratophyllidae) Records From Colonial Nesting Birds

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    Banding and censusing large numbers of gull chicks over a 30-year period on Great Lakes islands has produced a collection of five individual ticks from two Herring Gull (Larus argentatus) chicks. The tick species, Hemaphysalis leporispalustris, found on the gulls is commonly found on Snowshoe Hares (Lepus americanus). Although this represents an apparently uncom­mon record on Herring Gulls, this host could be an important source of aerial vector dispersal during regular cyclic hare/tick population peaks. Populations of the flea, Ceratophyllus lari, have increased rapidly in ground nesting Double-crested Cormorant (Phalacrocorax auritus) colonies from none 16 years ago. The possibilities of disease transmission by both of these hematophagus ectoparasites are assessed with evidence from the literature. The tick and flea distributions reported here are new host records, and the flea is a new species record for Michigan

    Geographic Distribution of Siphonaptera Collected From Small Mammals on Lake Michigan Islands

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    The distribution of ten flea species collected from five small mammal host species on 13 Lake Michigan islands is described. Four new eastern and southern records for Hystrichopsylla dippiei Rothschild are given. Speculative suggestions are made regarding dispersal routes of some of the small mammal host species, and the distribution of flea species from Peromyscus maniculatus gracilis LeConte is dis- cussed in the context of island biogeography theory

    Additional Siphonaptera Records From Small Mammals in the Central Upper Peninsula of Michigan

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    Fleas were collected from mammals during the period 1990-1992 in two upper peninsula counties. Identified specimens were compared to existing distribution records for both parasite and host. Only those records which are newly documented for county, upper peninsula or Michigan are listed. We report one previously unknown flea species and five new host records for Michigan. One host record is new for the upper peninsula. In addition, seven new host/parasite combinations are recorded for two central upper peninsula counties

    ON THE MEASUREMENT OF A COSMOLOGICAL DIPOLE IN THE PHOTON NUMBER COUNTS OF GAMMA-RAY BURSTS

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    If gamma-ray bursts are cosmological or in a halo distribution their properties are expected to be isotropic (at least to 1st order). However, our motion with respect to the burst parent population (whose proper frame is expected to be that of the Cosmic Microwave Background (CMB), or that of a static halo) will cause a dipole effect in the distribution of bursts and in their photon number counts (together termed a Compton-Getting effect). We argue that the photon number count information is necessary to distinguish a genuine Compton-Getting effect from some other anisotropy and to fully test the proper frame isotropy of the bursts. Using the 2B burst catalogue and the dipole determined from the CMB, we find the surprising result that although the number weighted distribution is consistent with isotropy, the fluence weighted dipole has a correlation with the CMB dipole that has a probability of occuring only 10% of the time for an isotropic photon distribution. Furthermore, the photon and number dipoles are inconsistent under the hypothesis of isotropy, at the 2-sigma level. This could be an indication that a non-negligible fraction of gamma-ray bursts originate in the local, anisotropic universe. (shortened Abstract)Comment: Accepted by ApJ. Self-unpacking (use csh), uuencoded, compressed Postscript, 16 pages + 4 Figures (5 files

    Quantum Gravitational Bremsstrahlung, Massless versus Massive Gravity

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    The massive spin-2 quantum gauge theory previously developed is applied to calculate gravitational bremsstrahlung. It is shown that this theory is unique and free from defects. In particular, there is no strong coupling if the graviton mass becomes small. The cross sections go over smoothly into the ones of the massless theory in the limit of vanishing graviton mass. The massless cross sections are calculated for the full tensor theory.Comment: 13 pages, 1 figur

    Trions in a periodic potential

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    The group-theoretical classification of trion states is presented. It is based on considerations of products of irreducible representations of the 2D translation group. For a given BvK period N degeneracy of obtained states is N^2. Trions consist of two identical particles so the symmetrization of states with respect to particles transposition is considered. Completely antisymmetric states can be constructed by introducing antisymmetric spin functions. Two symmetry adapted bases are considered. The third possibility is postponed for the further investigations.Comment: revtex, 5 p., sub. to Physica

    Contextual variety, Internet-of-things and the choice of tailoring over platform : mass customisation strategy in supply chain management

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    This paper considers the implications for Supply Chain Management from the development of the Internet of Things (IoT) or Internet Connected Objects (ICO). We focus on the opportunities and challenges arising from consumption data as a result of ICO and how this can be translated into a provider’s strategy of offering different varieties of products. In our model, we consider two possible strategies: tailoring strategy and platform strategy. Tailoring strategy implies that a provider produces multiple varieties of a product that meet consumers’ needs. Platform strategy depicts the provider’s actions in offering a flexible and standardised platform which enables consumers’ needs to be met by incorporating personal ICO data onto various customisable applications independently produced by other providers that could be called on in context and on demand. We derive conditions under which each of the strategies may be profitable for the provider through maximising consumers’ value. We conclude by considering the implications for SCM research and practice including an extension of postponement taxonomies to include the customer as the completer of the product
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