42,834 research outputs found
A tale of two cinnamons: A comparative review of the clinical evidence of Cinnamomum verum and C. cassia as diabetes interventions
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
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
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
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
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
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
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
Valerian Root in Treating Sleep Problems and Associated Disorders—A Systematic Review and Meta-Analysis
Sleep problems are widely prevalent and associated with various comorbidities including anxiety. Valerian ( Valeriana officinalis L.) is a popular herbal medicine used as a sleep aid, however the outcomes of previous clinical studies are inconsistent. This study was conducted to update and re-evaluate the available data in order to understand the reason behind the inconsistent outcomes and to provide a broader view of the use of valerian for associated disorders. PubMed, ScienceDirect, and Cochrane Library were searched to retrieve publications relevant to the effectiveness of valerian as a treatment of sleep problems and associated disorders. A total of 60 studies (n=6,894) were included in this review, and meta-analyses were performed to evaluate the effectiveness to improve subjective sleep quality (10 studies, n=1,065) and to reduce anxiety (8 studies, n=535). Results suggested that inconsistent outcomes were possibly due to the variable quality of herbal extracts and that more reliable effects could be expected from the whole root/rhizome. In addition, therapeutic benefits could be optimized when it was combined with appropriate herbal partners. There were no severe adverse events associated with valerian intake in subjects aged between 7 and 80 years. In conclusion, valerian could be a safe and effective herb to promote sleep and prevent associated disorders. However, due to the presence of multiple active constituents and relatively unstable nature of some of the active constituents, it may be necessary to revise the quality control processes, including standardization methods and shelf life
Deconvolution and analysis of wide-angle longwave radiation data from Nimbus 6 Earth radiation budget experiment for the first year
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
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