626 research outputs found
Can exercise limits prevent post-exertional malaise in chronic fatigue syndrome? An uncontrolled clinical trial.
<b>Objective</b>: It was hypothesized that the use of exercise limits prevents symptom increases and worsening of their health status following a walking exercise in people with Chronic Fatigue Syndrome (CFS).
<b>Design</b>: An uncontrolled clinical trial (semi-experimental design).
<b>Setting</b>: Outpatient clinic of a university department.
<b>Subjects</b>: 24 patients with CFS.
<b>Interventions</b>: Subjects undertook a walking test with the two concurrent exercise limits. Each subject walked at an <i>intensity</i> where the maximum heart rate was determined by heart rate corresponding to the respiratory exchange ratio =1.0 derived from a previous sub-maximal exercise test and for a duration calculated from how long each patient felt they were able to walk.
<b>Main outcome measures</b>: The Short Form 36 Health Survey or SF-36, the CFS Symptom List, and the CFS-Activities and Participation Questionnaire were filled in prior to, immediately and 24 hours post-exercise.
<b>Results</b>: The fatigue increase observed immediately post-exercise (p=0.006) returned to pre-exercise levels 24 hours post-exercise. The increase in pain observed immediately post-exercise was retained at 24 hours post-exercise (p=0.03). Fourteen of 24 subjects experienced a clinically meaningful change in bodily pain (change of SF-36 bodily pain score Âł10). Six of 24 participants indicated that the exercise bout had slightly worsened their health status, and 2 of 24 had a clinically meaningful decrease in vitality (change of SF-36 vitality score Âł20). There was no change in activity limitations/participation restrictions.
<b>Conclusion</b>: It was shown that the use of exercise limits (limiting both the intensity and duration of exercise) prevents important health status changes following a walking exercise in people with CFS, but was unable to prevent short-term symptom increases
Safe food and feed through an integrated toolbox for mycotoxin management: the MyToolBox approach
There is a pressing need to mobilise the wealth of knowledge from the international mycotoxin research conductedover the past 25-30 years, and to perform cutting-edge research where knowledge gaps still exist. This knowledgeneeds to be integrated into affordable and practical tools for farmers and food processors along the chain inorder to reduce the risk of mycotoxin contamination of crops, feed and food. This is the mission of MyToolBox â a four-year project which has received funding from the European Commission. It mobilises a multi-actorpartnership (academia, farmers, technology small and medium sized enterprises, food industry and policystakeholders) to develop novel interventions aimed at achieving a significant reduction in crop losses due tomycotoxin contamination. Besides a field-to-fork approach, MyToolBox also considers safe use options ofcontaminated batches, such as the efficient production of biofuels. Compared to previous efforts of mycotoxin reduction strategies, the distinguishing feature of MyToolBox is to provide the recommended measures to theend users along the food and feed chain in a web-based MyToolBox platform (e-toolbox). The project focuseson small grain cereals, maize, peanuts and dried figs, applicable to agricultural conditions in the EU and China. Crop losses using existing practices are being compared with crop losses after novel pre-harvest interventionsincluding investigation of genetic resistance to fungal infection, cultural control (e.g. minimum tillage or cropdebris treatment), the use of novel biopesticides suitable for organic farming, competitive biocontrol treatment and development of novel modelling approaches to predict mycotoxin contamination. Research into post-harvestmeasures includes real-time monitoring during storage, innovative sorting of crops using vision-technology, novelmilling technology and studying the effects of baking on mycotoxins at an industrial scale
Fast particle-mesh code for Milgromian dynamics
Modified Newtonian dynamics (MOND) is a promising alternative to dark matter.
To further test the theory, there is a need for fluid- and particle-dynamics
simulations. The force in MOND is not a direct particle-particle interaction,
but derives from a potential for which a nonlinear partial differential
equation (PDE) needs to be solved. Normally, this makes the problem of
simulating dynamical evolution computationally expensive. We intend to develop
a fast particle-mesh (PM) code for MOND (the AQUAL formalism). We transformed
the nonlinear equation for MOND into a system of linear PDEs plus one algebraic
equation. An iterative scheme with the fast Fourier transform (FFT) produces
successively better numerical approximations. The algorithm was tested for
dynamical systems in MOND where analytical solutions are known: the two-body
problem, a body with a circular ring, and a spherical distribution of particles
in thermal equilibrium in the self-consistent potential. The PM code can
accurately calculate the forces at subpixel scale and reproduces the analytical
solutions. Four iterations are required for the potential, but when the spatial
steps are small compared to the kernel width, one iteration is suffices. The
use of a smoothing kernel for the accelerations is inevitable in order to
eliminate the self-gravity of the point particles. Our PDE solver is to
times as slow as a standard Poisson solver. However, the smoothing and
particle propagation takes up most of the time above one particle per
pixels. The FFTs, the smoothing, and the propagation part in the code can all
be parallelized.Comment: 13 pages, 13 figure
Non-destructive characterization of nitrogen-implanted silicon-on-insulator structures by spectroscopic ellipsometry
Silicon-on-insulator (SOI) structures implanted with 200 or 400 keV N+ ions at a dose of 7.5 Ă 1017cmâ2 were studied by spectroscopic ellipsometry (SE). The SE measurements were carried out in the 300â700 nm wavelength (4.13-1.78 eV photon energy) range. The SE data were analysed by the conventional method of using appropriate optical models and linear regression analysis. We applied a seven-layer model (a surface oxide layer, a thick silicon layer, upper two interface layers, a thick nitride layer and lower two interface layers) with good results. The fitted parameters were the layer thickness and compositions. The results were compared with data obtained from Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy. The sensitivity of our optical model and fitting technique was good enough to distinguish between the silicon-rich transition layers near the upper and lower interfaces of the nitride layer, which are unresolvable in RBS measurements
Vicinal Surfaces and the Calogero-Sutherland Model
A miscut (vicinal) crystal surface can be regarded as an array of meandering
but non-crossing steps. Interactions between the steps are shown to induce a
faceting transition of the surface between a homogeneous Luttinger liquid state
and a low-temperature regime consisting of local step clusters in coexistence
with ideal facets. This morphological transition is governed by a hitherto
neglected critical line of the well-known Calogero-Sutherland model. Its exact
solution yields expressions for measurable quantities that compare favorably
with recent experiments on Si surfaces.Comment: 4 pages, revtex, 2 figures (.eps
Accelerated Molecular Vibrational Decay and Suppressed Electronic Nonlinearities in Plasmonic Cavities through Coherent Raman Scattering
Molecular vibrations and their dynamics are of outstanding importance for
electronic and thermal transport in nanoscale devices as well as for molecular
catalysis. The vibrational dynamics of <100 molecules are studied through
three-colour time-resolved coherent anti-Stokes Raman spectroscopy (trCARS)
using plasmonic nanoantennas. This isolates molecular signals from four-wave
mixing (FWM), while using exceptionally low nanowatt powers to avoid molecular
damage via single-photon lock-in detection. FWM is found to be strongly
suppressed in nm-wide plasmonic gaps compared to plasmonic nanoparticles. The
ultrafast vibrational decay rates of biphenyl-4-thiol molecules are accelerated
ten-fold by a transient rise in local non-equilibrium temperature excited by
enhanced, pulsed optical fields within these plasmonic nanocavities. Separating
the contributions of vibrational population decay and dephasing carefully
explores the vibrational decay channels of these tightly confined molecules.
Such extreme plasmonic enhancement within nanogaps opens up prospects for
measuring single-molecule vibrationally-coupled dynamics and diverse molecular
optomechanics phenomena
Randomized controlled study of pain education in patients receiving radiotherapy for painful bone metastases
BACKGROUND: Although short-course radiotherapy is an effective treatment for patients with painful bone metastases, pain is not always sufficiently controlled. We therefore investigated the additional effect of a nurse-led pain education program on pain control and quality of life (QoL).PATIENTS AND METHODS: In this multicenter study, patients with solid tumor bone metastases and a worst pain intensity of â„5 on a 0-10 numeric rating scale (NRS) were randomized between care as usual (control-group) and care as usual plus the Pain Education Program (PEP-group). PEP consisted of a structured interview and personalized education with follow-up phone calls. Patients completed the Brief Pain Inventory, EORTC QLQ-C15-PAL and BM22 at week 0, 1, 4, 8 and 12. The primary outcome was pain control, defined as the number of patients whose worst pain intensity was <5 on a 0-10 NRS after 12 weeks. Secondary outcomes were time to reach control of pain (NRS < 5), mean worst pain and average pain, and QoL at weeks 1, 4, 8 and 12.RESULTS: Of 308 included patients, 182 (92 PEP-group) completed 12 weeks follow-up. At 12 weeks, more patients in the PEP-group (71%) compared to the control-group (52%) reported pain control (P =.008). In the PEP-group, pain control was reached earlier than in the control-group (median 29 days versus 56 days; P =.003). Mean worst and average pain decreased in both groups but decreased more in the PEP-group. QoL did not differ between the groups.CONCLUSION: The addition of PEP to care as usual for patients treated with radiotherapy for painful bone metastases resulted in less pain and faster pain control.</p
Field-induced Ordering in Critical Antiferromagnets
Transfer-matrix scaling methods have been used to study critical properties
of field-induced phase transitions of two distinct two-dimensional
antiferromagnets with discrete-symmetry order parameters: triangular-lattice
Ising systems (TIAF) and the square-lattice three-state Potts model (SPAF-3).
Our main findings are summarised as follows. For TIAF, we have shown that the
critical line leaves the zero-temperature, zero -field fixed point at a finite
angle. Our best estimate of the slope at the origin is . For SPAF-3 we provided evidence that the zero-field correlation
length diverges as , with , through analysis of the critical curve at plus crossover
arguments. For SPAF-3 we have also ascertained that the conformal anomaly and
decay-of-correlations exponent behave as: (a) H=0: ; (b) .Comment: RevTex, 7 pages, 4 eps figures, to be published in Phys. Rev.
Connecting polymers to the quantum Hall plateau transition
A mapping is developed between the quantum Hall plateau transition and
two-dimensional self-interacting lattice polymers. This mapping is exact in the
classical percolation limit of the plateau transition, and diffusive behavior
at the critical energy is shown to be related to the critical exponents of a
class of chiral polymers at the -point. The exact critical exponents of
the chiral polymer model on the honeycomb lattice are found, verifying that
this model is in the same universality class as a previously solved model of
polymers on the Manhattan lattice. The mapping is obtained by averaging
analytically over the local random potentials in a previously studied lattice
model for the classical plateau transition. This average generates a weight on
chiral polymers associated with the classical localization length exponent . We discuss the differences between the classical and quantum
transitions in the context of polymer models and use numerical results on
higher-moment scaling laws at the quantum transition to constrain possible
polymer descriptions. Some properties of the polymer models are verified by
transfer matrix and Monte Carlo studies.Comment: 9 pages, 2 figure
Effects of climate warming and declining species richness in grassland model ecosystems: acclimation of CO2 fluxes
To study the effects of warming and declining species richness on the carbon balance of grassland communities, model ecosystems containing one, three or nine species were exposed to ambient and elevated (ambient +3°C) air temperature. In this paper, we analyze measured ecosystem CO2 fluxes to test whether ecosystem photosynthesis and respiration had acclimated to warming after 28 months of continuous heating, and whether the degree of acclimation depended on species richness. In order to test whether acclimation occurred, short term temperature response curves were established for all communities in both treatments. At similar temperatures, lower flux rates in the heated communities as compared to the unheated communities would indicate thermal acclimation. Because plant cover was significantly higher in the heated treatment, we normalized the data for plant cover. Subsequently, down-regulation of both photosynthesis and respiration was observed. Although CO2 fluxes were larger in communities with higher species richness, species richness did not affect the degree of acclimation to warming. These results imply that models need to take thermal acclimation into account to simulate photosynthesis and respiration in a warmer world.This research was funded by the Fund for
Scientific Research â Flanders (Belgium) as project âeffects of biodiversity loss and climate warming on carbon sequestration
mechanisms in terrestrial ecosystemsâ, contract #G.0434.03N. H. J. De Boeck holds a grant from the Institute for the Promotion
of Innovation by science and Technology in Flanders. P. Serrano-Ortiz benefits from a pre-doctoral grant from the Junta
de AndalucĂa
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