42,504 research outputs found

    A tale of two cinnamons: A comparative review of the clinical evidence of Cinnamomum verum and C. cassia as diabetes interventions

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    Objective: This review investigates the effectiveness of two cinnamon species, Cinnamomum verum and C. cassia, in diabetes management; their impact on related health conditions and relevant parameters in healthy individuals and safety issues. Methods: PubMed, Cochrane Library, and ScienceDirect were searched from 2000 up to April 2018 for clinical trials using either C. verum or C. cassia in controlling blood glucose and other diabetes-related parameters and conditions. Results: A total of twenty-five studies (n=997) were included for reviewing clinical evidence. Among these trials, fifteen studies investigated the effects on type II diabetes mellitus (T2DM) patients (n=831), four investigated subjects with related clinical conditions (n=82), and six investigated healthy individuals (n=84). Nineteen studies used C. cassia and six used C. verum. Results suggested C. cassia helped manage diabetes at 3-6g, while the effectiveness of C. verum remained inconclusive. In addition, the chemical properties of C. cassia and C. verum differ considerably. Of note, C. cassia contains high levels of the potentially hepatotoxic constituent coumarin. A skin rash was the only adverse event reported. Conclusion: While evidence supports the therapeutic benefit of C. cassia, interchangeability of C. cassia and C. verum remains inconclusive. Further research is warranted to address the effectiveness and safety of these cinnamon species. Given the potential hepatotoxicity of C. cassia, RCTs that include liver function tests are required. Robust RCTs on C. verum are recommended to establish if its efficacy can match its safety profile

    SIMLA: Simulating laser-particle interactions via classical and quantum electrodynamics

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    We present the Fortran code SIMLA, which is designed for the study of charged particle dynamics in laser and other background fields. This can be done classically via the Landau-Lifshitz equation, or alternatively, via the simulation of photon emission events determined by strong-field quantum-electrodynamics amplitudes and implemented using Monte-Carlo type routines. Multiple laser fields can be included in the simulation and the propagation direction, beam shape (plane wave, focussed paraxial, constant crossed, or constant magnetic), and time envelope of each can be independently specified.Comment: Submitted to Comp. Phys. Comm. The associated computer program and corresponding manual will be made available on the CPC librar

    Transverse spreading of electrons in high-intensity laser fields

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    We show that for collisions of electrons with a high-intensity laser, discrete photon emissions introduce a transverse beam spread which is distinct from that due to classical (or beam shape) effects. Via numerical simulations, we show that this quantum induced transverse momentum gain of the electron is manifest in collisions with a realistic laser pulse of intensity within reach of current technology, and we propose it as a measurable signature of strong-field quantum electrodynamics.Comment: 5 pages, 3 figures. Accepted for publication in Physical Review Letter

    Parameter estimation applied to Nimbus 6 wide-angle longwave radiation measurements

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    A parameter estimation technique was used to analyze the August 1975 Nimbus 6 Earth radiation budget data to demonstrate the concept of deconvolution. The longwave radiation field at the top of the atmosphere is defined from satellite data by a fifth degree and fifth order spherical harmonic representation. The variations of the major features of the radiation field are defined by analyzing the data separately for each two-day duty cycle. A table of coefficient values for each spherical harmonic representation is given along with global mean, gradients, degree variances, and contour plots. In addition, the entire data set is analyzed to define the monthly average radiation field

    Non-renormalisation Conditions in Type II String Theory and Maximal Supergravity

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    This paper considers general features of the derivative expansion of Feynman diagram contributions to the four-graviton scattering amplitude in eleven-dimensional supergravity compactified on a two-torus. These are translated into statements about interactions of the form D^2k R^4 in type II superstring theories, assuming the standard M-theory/string theory duality relationships, which provide powerful constraints on the effective interactions. In the ten-dimensional IIA limit we find that there can be no perturbative contributions beyond k string loops (for k>0). Furthermore, the genus h=k contributions are determined exactly by the one-loop eleven-dimensional supergravity amplitude for all values of k. A plausible interpretation of these observations is that the sum of h-loop Feynman diagrams of maximally extended supergravity is less divergent than might be expected and could be ultraviolet finite in dimensions d < 4 + 6/h -- the same bound as for N=4 Yang--Mills.Comment: 30 pages, 4 figures. v3 Some rewording, typos corrected and some references added. v4: Abstract rephrased. More typos corrected. Version to be publishe

    A sub-regional management framework for South Pacific longline fisheries

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    The principal objective of this study was to determine if additional net benefits can be derived from the sub-regional longline fishery by the introduction of a new management agreement that would centre on the provision of licensing arrangements that would allow access by eligible longline vessels to multiple Exclusive Economic Zones, i.e. Multi-zone Access. [90pp.

    Time-fixed rendezvous by impulse factoring with an intermediate timing constraint

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    A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods

    Deconvolution and analysis of wide-angle longwave radiation data from Nimbus 6 Earth radiation budget experiment for the first year

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    One year of longwave radiation data from July 1975 through June 1976 from the Nimbus 6 satellite Earth radiation budget experiment is analyzed by representing the radiation field by a spherical harmonic expansion. The data are from the wide field of view instrument. Contour maps of the longwave radiation field and spherical harmonic coefficients to degree 12 and order 12 are presented for a 12 month data period

    Modification of an impulse-factoring orbital transfer technique to account for orbit determination and maneuver execution errors

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    A method has previously been developed to satisfy terminal rendezvous and intermediate timing constraints for planetary missions involving orbital operations. The method uses impulse factoring in which a two-impulse transfer is divided into three or four impulses which add one or two intermediate orbits. The periods of the intermediate orbits and the number of revolutions in each orbit are varied to satisfy timing constraints. Techniques are developed to retarget the orbital transfer in the presence of orbit-determination and maneuver-execution errors. Sample results indicate that the nominal transfer can be retargeted with little change in either the magnitude (Delta V) or location of the individual impulses. Additonally, the total Delta V required for the retargeted transfer is little different from that required for the nominal transfer. A digital computer program developed to implement the techniques is described
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