538 research outputs found
A Preliminary Study of the Effectiveness of Chinese Therapeutic Food on Regulating Female Reproductive Hormones
This study investigated the effectiveness of Chinese therapeutic food on female reproductive hormones in a double-blind, placebo-controlled clinical trial. Chinese kiwi fruit extract (Hong En No. 1) was provided for Australian peri-menopausal women for one month. Chinese medical assessment and urinary 2-hydroxyestrone (2-OHE) and 16alpha-hydroxyestrone (16alpha-OHE) tests were conducted. Twenty-six urinary samples (pre and post-trial) which met the requirement of testing were analysed, the ratio 2-OHE:16alpha-OHE of pre-trial (1.18 ± 0.34) and post-trial (0.97 ± 0.29) in the control group (n = 6) decreased but showed no significant change, this ratio of pre-trial (1.44 ± 0.16) and post-trial (1.65 ± 0.21) in the treatment group (n = 7) indicated an improvement (P = 0.066), which results in beneficial hormone regulation. The Chinese medicine assessment indicated that the patterns of disharmony mainly include Liver Qi stagnation and Liver-Kidney Yin deficiency patterns. No significant change observed in the control group, significant score reduction of the patterns of disharmony was achieved at post-trial in the treatment group, which indicates an improvement of general health condition
Noise in Vortex Matter
URL: http://www-spht.cea.fr/articles/S03/018 (sur invitation).International audienceThe large increase in the flux-flow voltage noise, commonly observed in the vicinity of the peak-effect in super- conductors, is ascribed to a novel noise mechanism. The mechanism consists in random injection of the strongly pinned metastable disordered vortex phase through the sample edges and its subsequent random annealing into the weakly pinned ordered phase in the bulk. This results in large critical current fluctuations causing strong vortex velocity fluctuations. The excess noise due to this dynamic admixture of two vortex phases is found to dis- play pronounced reentrant behavior. In the Corbino geometry the injection of the metastable phase is prevented and, accordingly, the excess noise disappears. Excess flux-flow noise in the peak effect regime is dominated by vortex velocity fluctuations while the density fluctuations, frequently considered in the conventional flux-flow noise models, are negligibly weak. Strong nongaussian fluctuations are associated with S-shaped current-voltage characteristics. The spectral properties of the noise reflect the first order filter-like response of the dynamically coexisting vortex phases. The cutoff frequency in the spectra corresponds to the time-of-flight of vortices through the disordered part of the sample
Structural identifiability of surface binding reactions involving heterogeneous analyte : application to surface plasmon resonance experiments
Binding affinities are useful measures of target interaction and have an important role in understanding biochemical reactions that involve binding mechanisms. Surface plasmon resonance (SPR) provides convenient real-time measurement of the reaction that enables subsequent estimation of the reaction constants necessary to determine binding affinity. Three models are
considered for application to SPR experiments—the well mixed Langmuir model and two models that represent the binding reaction in the presence of transport effects. One of these models, the effective rate constant approximation, can be derived from the other by applying a quasi-steady state assumption. Uniqueness of the reaction constants with respect to SPR measurements
is considered via a structural identifiability analysis. It is shown that the models are structurally unidentifiable unless the sample concentration is known. The models are also considered for analytes with heterogeneity in the binding kinetics. This heterogeneity further confounds the identifiability of key parameters necessary for reliable estimation of the binding affinit
Camera motion estimation through planar deformation determination
In this paper, we propose a global method for estimating the motion of a
camera which films a static scene. Our approach is direct, fast and robust, and
deals with adjacent frames of a sequence. It is based on a quadratic
approximation of the deformation between two images, in the case of a scene
with constant depth in the camera coordinate system. This condition is very
restrictive but we show that provided translation and depth inverse variations
are small enough, the error on optical flow involved by the approximation of
depths by a constant is small. In this context, we propose a new model of
camera motion, that allows to separate the image deformation in a similarity
and a ``purely'' projective application, due to change of optical axis
direction. This model leads to a quadratic approximation of image deformation
that we estimate with an M-estimator; we can immediatly deduce camera motion
parameters.Comment: 21 pages, version modifi\'ee accept\'e le 20 mars 200
Dynamic transition in driven vortices across the peak effect in superconductors
We study the zero-temperature dynamic transition from the disordered flow to
an ordered flow state in driven vortices in type-II superconductors. The
transition current is marked by a sharp kink in the
characteristic with a concomitant large increase in the defect concentration.
On increasing magnetic field , the follows the behaviour of the
critical current . Specifically, in the peak effect regime
increases rapidly along with . We also discuss the effect of varying
disorder strength on .Comment: 4 pages, 4 figure
Vortex Pinball Under Crossed AC Drives in Superconductors with Periodic Pinning Arrays
Vortices driven with both a transverse and a longitudinal AC drive which are
out of phase are shown to exhibit a novel commensuration-incommensuration
effect when interacting with periodic substrates. For different AC driving
parameters, the motion of the vortices forms commensurate orbits with the
periodicity of the pinning array. When the commensurate orbits are present,
there is a finite DC critical depinning threshold, while for the incommensurate
phases the vortices are delocalized and the DC depinning threshold is absent.Comment: 4 pages, 4 postscript figure
Dakota Gold®-brand dried distiller’s grains with solubles: effects on finishing performance and carcass characteristics
A 153-day trial was conducted using
345 heifers to determine optimal level of
Dakota Gold dried distiller’s grains with
solubles (DDGS) in finishing diets based
on steam-flaked corn. Diets contained six
levels of DDGS: 0%, 15%, 30%, 45%,
60%, and 75%. DDGS affected average
daily gain, final weight and hot carcass
weight, all of which increased with 15%
DDGS and then decreased as additional
DDGS was added. Growth performance of
heifers fed 30% DDGS was similar to those
fed no DDGS. In general, heifers were
overfinished, with 61% being Yield Grade
3 or greater and 83% grading Choice or
Prime. Backfat tended to decrease with
addition of DDGS, and kidney, pelvic, and
heart fat and marbling scores tended to be
greatest for intermediate levels of DDGS.
Percentage of carcasses grading Choice or
Prime tended to be lower for heifers fed 60
or 75% DDGS
V-I characteristics in the vicinity of order-disorder transition in vortex matter
The shape of the V-I characteristics leading to a peak in the differential
resistance r_d=dV/dI in the vicinity of the order-disorder transition in NbSe2
is investigated. r_d is large when measured by dc current. However, for a small
Iac on a dc bias r_d decreases rapidly with frequency, even at a few Hz, and
displays a large out-of-phase signal. In contrast, the ac response increases
with frequency in the absence of dc bias. These surprisingly opposite phenomena
and the peak in r_d are shown to result from a dynamic coexistence of two
vortex matter phases rather than from the commonly assumed plastic depinning.Comment: 12 pages 4 figures. Accepted for publication in PRB rapi
A Bayesian elicitation of veterinary beliefs regarding systemic dry cow therapy: variation and importance for clinical trial design
The two key aims of this research were: (i) to conduct a probabilistic elicitation to quantify the variation in veterinarians’ beliefs regarding the efficacy of systemic antibiotics when used as an adjunct to intra-mammary dry cow therapy and (ii) to investigate (in a Bayesian statistical framework) the strength of future research evidence required (in theory) to change the beliefs of practising veterinary surgeons regarding the efficacy of systemic antibiotics, given their current clinical beliefs.
The beliefs of 24 veterinarians in 5 practices in England were quantified as probability density functions. Classic multidimensional scaling revealed major variations in beliefs both within and between veterinary practices which included: confident optimism, confident pessimism and considerable uncertainty. Of the 9 veterinarians interviewed holding further cattle qualifications, 6 shared a confidently pessimistic belief in the efficacy of systemic therapy and whilst 2 were more optimistic, they were also more uncertain. A Bayesian model based on a synthetic dataset from a randomised clinical trial (showing no benefit with systemic therapy) predicted how each of the 24 veterinarians’ prior beliefs would alter as the size of the clinical trial increased, assuming that practitioners would update their beliefs rationally in accordance with Bayes’ theorem.
The study demonstrated the usefulness of probabilistic elicitation for evaluating the diversity and strength of practitioners’ beliefs. The major variation in beliefs observed raises interest in the veterinary profession's approach to prescribing essential medicines. Results illustrate the importance of eliciting prior beliefs when designing clinical trials in order to increase the chance that trial data are of sufficient strength to alter the clinical beliefs of practitioners and do not merely serve to satisfy researchers
Critical depinning force and vortex lattice order in disordered superconductors
We simulate the ordering of vortices and its effects on the critical current
in superconductors with varied vortex-vortex interaction strength and varied
pinning strengths for a two-dimensional system. For strong pinning the vortex
lattice is always disordered and the critical depinning force only weakly
increases with decreasing vortex-vortex interactions. For weak pinning the
vortex lattice is defect free until the vortex-vortex interactions have been
reduced to a low value, when defects begin to appear with a simultaneous rapid
increase in the critical depinning force. In each case the depinning force
shows a maximum for non-interacting vortices. The relative height of the peak
increases and the peak width decreases for decreasing pinning strength in
excellent agreement with experimental trends associated with the peak effect.
We show that scaling relations exist between the distance between defects in
the vortex lattice and the critical depinning force.Comment: 5 pages, 6 figure
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