14,117 research outputs found

    Study of the Anatomy of the Alimentary Canal of Brochymena quadripustulata (Hemiptera:Pentatomidae)

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    An anatomical study of the alimentary canal and associated salivary apparatus was conducted for the pentatomid, Brochymena quadripustulata. The esophagus, ventriculus, pylorus, rectum, principal salivary glands and ducts are described and illustrated. Described structures of Brochymena quadripustulata are compared with various species of pentatomids and other hemipterans

    Is obesity a disease?

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    Shakespeare said that a rose by any other name would smell as sweet. Analogously, obesity as a clinical entity based on its current definition of a BMI>30Kg/m2 remains essentially the same thing, whatever we name it. Unfortunately however, BMI which is calculated from just two basic anthropometric measurements, is seriously limited as a sole diagnostic criterion for obesity. It is accepted that on a population-based epidemiological level, BMI appears to perform well as a measure of adiposity [1]. Although BMI usually also correlates well with adiposity on an individual level, ‘excessive adiposity’ as a concept seems quite subjective. Furthermore, BMI also correlates with muscularity, and therefore stumbles as a definition of obesity in some people with excessive muscularity. Finally, ‘excessive adiposity’ may occur at a BMI <30Kg/m2 in some people with sarcopenia for example. BMI as an indicator of ‘excessive adiposity’ is therefore inherently flawed, particularly in those people with abnormal body habitus. A further limitation of BMI is that it provides no indication of body fat distribution. It is well-established that fat distribution (such as visceral versus subcutaneous gluteal fat) influences risk of metabolic dysfunction and co-morbidity development [2]. Although waist circumference is a useful measure of visceral fat, this measurement does not feature as a diagnostic criterion for obesity based on its current definition

    Dissecting the Interplay Between Elected Members and Officials in Board Level Technology Decisions: the case of a local authority in England

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    Digital investment and the successful selection and implementation of technology is crucial to local government success and yet there is a dearth of research evaluating how these decisions are made. And yet there is a dearth of research evaluating how Boards and executives of all kinds make these decisions and the role they play in influencing asset deployment in the digital space. In this regard, government, and especially local government is not only sparsely investigated as part of the existing body of knowledge but does not function neatly when compared to commercial organizations and the profit motive. This paper addresses the shortfall by investigating the interplay between elected members and Boards of local government in terms of complex decision-making processes surrounding technology investment. Empirically, this research adopts a case study approach and qualitative questioning of key elected and appointed actors allowing us to dissect the phenomenon

    Systems comparison of direct and relay link data return modes for advanced planetary missions

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    Advanced planetary missions using direct and relay link data return mode

    Flight evaluation of advanced control systems and displays on a general aviation airplane

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    A flight-test program was conducted to determine the effect of advanced flight control systems and displays on the handling qualities of a light twin-engined airplane. A flight-director display and an attitude-command control system, used separately and in combination, transformed a vehicle with poor handling qualities during ILS approaches in turbulent air into a vehicle with good handling qualities. The attitude-command control system also improved the ride qualities of the airplane. A rate-command control system made only small improvements to the airplane's ILS handling qualities in turbulence. Both the rate- and the attitude-command control systems reduced stall warning in the test airplane, increasing the likelihood of inadvertent stalls. The final approach to the point of flare was improved by both the rate- and the attitude-command control systems. However, the small control wheel deflections necessary to flare were unnatural and tended to cause overcontrolling during flare. Airplane handling qualities are summarized for each control-system and display configuration

    Exploring complex networks by walking on them

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    We carry out a comparative study on the problem for a walker searching on several typical complex networks. The search efficiency is evaluated for various strategies. Having no knowledge of the global properties of the underlying networks and the optimal path between any two given nodes, it is found that the best search strategy is the self-avoid random walk. The preferentially self-avoid random walk does not help in improving the search efficiency further. In return, topological information of the underlying networks may be drawn by comparing the results of the different search strategies.Comment: 5 pages, 5 figure

    Monopole Percolation in the Compact Abelian Higgs Model

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    We have studied the monopole-percolation phenomenon in the four dimensional Abelian theory that contains compact U(1) gauge fields coupled to unitary norm Higgs fields. We have determined the location of the percolation transition line in the plane (βg,βH)(\beta_g, \beta_H). This line overlaps the confined-Coulomb and the confined-Higgs phase transition lines, originated by a monopole-condensation mechanism, but continues away from the end-point where this phase transition line stops. In addition, we have determined the critical exponents of the monopole percolation transition away from the phase transition lines. We have performed the finite size scaling in terms of the monopole density instead of the coupling, because the density seems to be the natural parameter when dealing with percolation phenomena.Comment: 13 pages. REVTeX. 16 figs. included using eps

    Quasiperiodic spin-orbit motion and spin tunes in storage rings

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    We present an in-depth analysis of the concept of spin precession frequency for integrable orbital motion in storage rings. Spin motion on the periodic closed orbit of a storage ring can be analyzed in terms of the Floquet theorem for equations of motion with periodic parameters and a spin precession frequency emerges in a Floquet exponent as an additional frequency of the system. To define a spin precession frequency on nonperiodic synchro-betatron orbits we exploit the important concept of quasiperiodicity. This allows a generalization of the Floquet theorem so that a spin precession frequency can be defined in this case too. This frequency appears in a Floquet-like exponent as an additional frequency in the system in analogy with the case of motion on the closed orbit. These circumstances lead naturally to the definition of the uniform precession rate and a definition of spin tune. A spin tune is a uniform precession rate obtained when certain conditions are fulfilled. Having defined spin tune we define spin-orbit resonance on synchro--betatron orbits and examine its consequences. We give conditions for the existence of uniform precession rates and spin tunes (e.g. where small divisors are controlled by applying a Diophantine condition) and illustrate the various aspects of our description with several examples. The formalism also suggests the use of spectral analysis to ``measure'' spin tune during computer simulations of spin motion on synchro-betatron orbits.Comment: 62 pages, 1 figure. A slight extension of the published versio

    Density Matrix Renormalization Group Study of the Disorder Line in the Quantum ANNNI Model

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    We apply Density Matrix Renormalization Group methods to study the phase diagram of the quantum ANNNI model in the region of low frustration where the ferromagnetic coupling is larger than the next-nearest-neighbor antiferromagnetic one. By Finite Size Scaling on lattices with up to 80 sites we locate precisely the transition line from the ferromagnetic phase to a paramagnetic phase without spatial modulation. We then measure and analyze the spin-spin correlation function in order to determine the disorder transition line where a modulation appears. We give strong numerical support to the conjecture that the Peschel-Emery one-dimensional line actually coincides with the disorder line. We also show that the critical exponent governing the vanishing of the modulation parameter at the disorder transition is βq=1/2\beta_q = 1/2.Comment: 4 pages, 5 eps figure

    Partial entropy in finite-temperature phase transitions

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    It is shown that the von Neumann entropy, a measure of quantum entanglement, does have its classical counterpart in thermodynamic systems, which we call partial entropy. Close to the critical temperature the partial entropy shows perfect finite-size scaling behavior even for quite small system sizes. This provides a powerful tool to quantify finite-temperature phase transitions as demonstrated on the classical Ising model on a square lattice and the ferromagnetic Heisenberg model on a cubic lattice.Comment: 4 pages, 6 figures, Revised versio
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