1,653 research outputs found
The effect of long-term high-fibre diets in diabetic outpatients
Diets containing large amounts of dietary fibre have been shown to be beneficial in improving diabetic control. We -investigated the practical aspects of administering a high-fibre diet to diabetic outpatients in Cape Town, using readily available, lowcost foodstuffs with a high dietary fibre content. Ten patients were followed up over a period of 9 months, for 3 months of which a high-fibre diet was prescribed. Although only 3 patients approached the projected dietary fibre intake, significant negative correlations were found between the mean plasma glucose changes and the dietary fibre increments (r = -0,704; P < 0,05) and between the mean serum triglyceride changes and the dietary fibre increments (r =-0,741; P < 0,05). These findings suggest that, were it not for poor dietary compliance, a high-fibre diet might result in significant improvement in diabetic control, and that education and motivation are of prime importance when making major changes to patients eating habits
Stokes-space formalism for Bragg scattering in a fiber
Optical frequency conversion by four-wave mixing (Bragg scattering) in a
fiber is considered. The evolution of this process can be modeled using the
signal and idler amplitudes, which are complex, or Stokes-like parameters,
which are real. The Stokes-space formalism allows one to visualize power and
phase information simultaneously, and produces a simple evolution equation for
the Stokes parameters
Structure determination of PF3 adsorption on Cu(100) using X-ray standing waves
The local structure of the Cu(100)c(4x2)-PF3 adsorption phase has been investigated through the use of normal-incidence X-ray standing waves (NIXSW), monitored by P 1s and F 1s photoemission, together with P K-edge near-edge X-ray absorption fine structure (NEXAFS). NEXAFS shows the molecule to be oriented with its C3v symmetry axis essentially perpendicular to the surface, while the P NIXSW data show the molecule to be adsorbed in atop sites 2.37±0.04 Ă
above the surface, this distance corresponding to the Cu-P nearest-neighbour distance in the absence of any surface relaxation. F NIXSW indicates a surprisingly small height difference of the P and F atoms above the surface 0.44±0.06 Ă
, compared with the value expected for an undistorted gas-phase geometry of 0.77 Ă
, implying significant increases in the F-P-F bond angles. In addition, however, the F NIXSW data indicate that the molecules have a well-defined azimuthal orientation with a molecular mirror plane aligned in a substrate mirror plane, and with a small (5-10°) tilt of the molecule in this plane such that the two symmetrically-equivalent F atoms in each molecule are tilted down towards the surface
Electromagnetic Dissociation of Nuclei in Heavy-Ion Collisions
Large discrepancies have been observed between measured Electromagnetic
Dissociation(ED) cross sections and the predictions of the semiclassical
Weiz\"acker-Williams-Fermi(WWF) method. In this paper, the validity of the
semiclassical approximation is examined. The total cross section for
electromagnetic excitation of a nuclear target by a spinless projectile is
calculated in first Born approximation, neglecting recoil. The final result is
expressed in terms of correlation functions and convoluted densities in
configuration space. The result agrees with the WWF approximation to leading
order(unretarded electric dipole approximation), but the method allows an
analytic evaluation of the cutoff, which is determined by the details of the
electric dipole transition charge density. Using the Goldhaber-Teller model of
that density, and uniform charge densities for both projectile and target, the
cutoff is determined for the total cross section in the nonrelativistic limit,
and found to be smaller than values currently used for ED calculations. In
addition, cross sections are calculated using a phenomenological momentum space
cutoff designed to model final state interactions. For moderate projectile
energies, the calculated ED cross section is found to be smaller than the
semiclassical result, in qualitative agreement with experiment.Comment: 28 page
Floc formation reduces the pH stress experienced by microorganisms living in alkaline environments
The survival of microorganisms within a cementitious geological disposal facility for radioactive wastes is heavily dependent on their ability to survive the calcium dominated, hyper-alkaline conditions resulting from the dissolution of the cementitious materials. The present study shows that the formation of flocs, composed of a complex mixture of extracellular polymeric substances (EPS), provides protection against alkaline pH values up to pH 13.0. The flocs were dominated by Alishewanella and Dietzia sp, producing a mannose rich carbohydrate fraction incorporating extracellular DNA, resulting in Ca2+ sequestration. EPS provided a ~10 ”m thick layer around the cells within the centre of the flocs, which were capable of growth at pH 11.0 and 11.5, maintaining internal pH values of pH 10.4 and 10.7 respectively. Survival was observed at pH 12.0, where an internal floc pH of 11.6 was observed alongside a reduced associated biomass. Limited floc survival (<2 weeks) was observed at pH 13.0.This study demonstrates that flocs are able to maintain a lower internal pH in response to the hyperalkaline conditions expected to occur within a cementitious, geological disposal facility for radioactive wastes and indicates that floc communities within such a facility would be capable of survival up to a pH of 12.0
UK monitoring and deposition of tephra from the May 2011 eruption of GrĂmsvötn, Iceland
Mapping the transport and deposition of tephra is important for the assessment of an eruptionâs impact on health, transport, vegetation and infrastructure, but it is challenging at large distances from a volcano (>â1000 km), where it may not be visible to the naked eye. Here we describe a range of methods used to quantify tephra deposition and impact on air quality during the 21â28 May 2011 explosive basaltic eruption of GrĂmsvötn volcano, Iceland. Tephra was detected in the UK with tape-on-paper samples, rainwater samples, rainwater chemistry analysis, pollen slides and air quality measurements. Combined results show that deposition was mainly in Scotland, on 23â25 May. Deposition was patchy, with adjacent locations recording different results. Tape-on-paper samples, collected by volunteer citizen scientists, and giving excellent coverage across the UK, showed deposition at latitudes >55°N, mainly on 24 May. Rainwater samples contained ash grains mostly 20â30 ÎŒmâlong (maximum recorded grainsize 80 ÎŒm) with loadings of up to 116 grainscm-2. Analysis of rainwater chemistry showed high concentrations of dissolved Fe and Al in samples from N Scotland on 24â27 May. Pollen slides recorded small glass shards (3â4 ÎŒmâlong) deposited during rainfall on 24â25 May and again on 27 May. Air quality monitoring detected increased particulate matter concentrations in many parts of the country. An hourly concentration of particles â53°N) on 24 May but no negative effects on health were reported. Although the eruption column reached altitudes of 20 km above sea level, air mass trajectories suggest that only tephra from the lowest 4 km above sea level of the eruption plume was transported to the UK. This demonstrates that even low plumes could deliver tephra to the UK and suggests that the relative lack of basaltic tephra in the tephrochronological record is not due to transport processes
Dynamics of two colliding Bose-Einstein condensates in an elongated magneto-static trap
We study the dynamics of two interacting Bose-Einstein condensates, by
numerically solving two coupled Gross-Pitaevskii equations at zero temperature.
We consider the case of a sudden transfer of atoms between two trapped states
with different magnetic moments: the two condensates are initially created with
the same density profile, but are trapped into different magnetic potentials,
whose minima are vertically displaced by a distance much larger than the
initial size of both condensates. Then the two condensates begin to perform
collective oscillations, undergoing a complex evolution, characterized by
collisions between the two condensates. We investigate the effects of their
mutual interaction on the center-of-mass oscillations and on the time evolution
of the aspect ratios. Our theoretical analysis provides a useful insight into
the recent experimental observations by Maddaloni et al., cond-mat/0003402.Comment: 8 pages, 7 figures, RevTe
Do South African international cricket pace bowlers have similar bowling volume and injury risk associates compared to other elite fast bowlers?
BACKGROUND
While many cricket-playing nations have conducted research on bowling volume (BV) and injury risk, this relationship among international South African pace bowlers is yet to be investigated. Environmental, socio-economic, and training strategy differences warrant similar research in a South African context. The purpose of this preliminary study was to establish if South African pace bowlers have similar bowling volume and injury associates compared to other elite fast bowlers.
METHODS
This study was a prospective, observational, cohort study that monitored match and training BV and injuries among pace bowlers playing for the South African national team between April 2017 and April 2019. A sample of convenience that included fourteen bowlers was selected. Bowling volume was quantified as the number of deliveries bowled during training and competition. Acute-, chronic- and acute: chronic bowling volume ratios were independently modeled as association variables.
RESULTS
There were 39 injuries with the most being to the lumbar spine (25.64%). Moderate-to-low and a moderate-to-high acute: chronic bowling load ratios were associated with a lower risk of injury. Chronic bowling load was associated with injury (z = 2.82, p = 0.01). A low acute workload, low chronic workload, moderate-high chronic workload, and moderate-low acute: chronic ratio was also associated with an increased risk of injury.
CONCLUSION
These findings confirm that there appears to be a dose-response effect between training bowling volume and the likelihood of an injury occurring with a moderate-to-low and a moderate-to-high bowling volume ratio being optimal. Considering the small sample size, the findings should be interpreted with caution
A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. I. Theory
We derive an analytical approximation of nonlinear force-free magnetic field
solutions (NLFFF) that can efficiently be used for fast forward-fitting to
solar magnetic data, constrained either by observed line-of-sight magnetograms
and stereoscopically triangulated coronal loops, or by 3D vector-magnetograph
data. The derived NLFFF solutions provide the magnetic field components
, , , the force-free parameter
, the electric current density , and are
accurate to second-order (of the nonlinear force-free -parameter). The
explicit expressions of a force-free field can easily be applied to modeling or
forward-fitting of many coronal phenomena.Comment: Solar Physics (in press), 26 pages, 11 figure
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