1,459 research outputs found
The I-mode confinement regime at ASDEX Upgrade: global propert ies and characterization of strongly intermittent density fluctuations
Properties of the Imode confinement regime on the ASDEX Upgrade tokamak are
summarized. A weak dependence of the power threshold for the LI transition on the toroidal
magnetic field strength is found. During improved confinement, the edge radial electric field
well deepens. Stability calculations show that the Imode pedestal is peelingballooning stable.
Turbulence investigations reveal strongly intermittent density fluctuations linked to the weakly
coherent mode in the confined plasma, which become stronger as the confinement quality
increases. Across all investigated structure sizes (
≈
⊥
k
5
–
12 cm
−
1
, with
⊥
k
the perpendicular
wavenumber of turbulent density fluctuations), the intermittent turbulence bursts are observed.
Comparison with bolometry data shows that they move poloidally toward the Xpoint and
finally end up in the divertor. This might be indicative that they play a role in inhibiting the
density profile growth, such that no pedestal is formed in the edge density profile.European Union (EUROfusion 633053)European Union (EUROfusion AWP15ENR09/IPP02
Assessment on experimental bacterial biofilms and in clinical practice of the efficacy of sampling solutions for microbiological testing of endoscopes
International audienceOpinions differ on the value of microbiological testing of endoscopes, which varies according to the technique used. We compared the efficacy on bacterial biofilms of sampling solutions used for the surveillance of the contamination of endoscope channels. To compare efficacy, we used an experimental model of a 48-h Pseudomonas biofilm grown on endoscope internal tubing. Sampling of this experimental biofilm was performed with a Tween 80-lecithin-based solution, saline, and sterile water. We also performed a randomized prospective study during routine clinical practice in our hospital sampling randomly with two different solutions the endoscopes after reprocessing. Biofilm recovery expressed as a logarithmic ratio of bacteria recovered on bacteria initially present in biofilm was significantly more effective with the Tween 80-lecithin-based solution than with saline solution (P = 0.002) and sterile water (P = 0.002). There was no significant difference between saline and sterile water. In the randomized clinical study, the rates of endoscopes that were contaminated with the Tween 80-lecithin-based sampling solution and the saline were 8/25 and 1/25, respectively (P = 0.02), and the mean numbers of bacteria recovered were 281 and 19 CFU/100 ml (P = 0.001), respectively. In conclusion, the efficiency and therefore the value of the monitoring of endoscope reprocessing by microbiological cultures is dependent on the sampling solutions used. A sampling solution with a tensioactive action is more efficient than saline in detecting biofilm contamination of endoscopes
Martin boundary of a reflected random walk on a half-space
The complete representation of the Martin compactification for reflected
random walks on a half-space is obtained. It is shown that the
full Martin compactification is in general not homeomorphic to the ``radial''
compactification obtained by Ney and Spitzer for the homogeneous random walks
in : convergence of a sequence of points to a
point of on the Martin boundary does not imply convergence of the sequence
on the unit sphere . Our approach relies on the large
deviation properties of the scaled processes and uses Pascal's method combined
with the ratio limit theorem. The existence of non-radial limits is related to
non-linear optimal large deviation trajectories.Comment: 42 pages, preprint, CNRS UMR 808
On non-zero space average density perturbation effects in tokamak plasma reflectometer signals
12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)The effects of the non-zero average density perturbation on phase and amplitude measured by reflectometry are presented. The non-zero average density perturbation on the phase variation can be seen as an index effect as soon as the shape of the density perturbation does not introduce spectral effects. Amplitude modulation in time follows generally the properties of the cut-off layer seen as a mirror but some specific situations produce a time modulation two times higher than the input time variation of the density perturbation as observed in Tore Supra. The introduction of secondary cut-off can exhibit this effect as shown in 2D simulations
Inner versus outer E×B shear layer: an attempt to radially localize the L-H transition
EUROfusion Consortium 63305
A national cross-sectional survey of dental anxiety in the French adult population
<p>Abstract</p> <p>Background</p> <p>Dental anxiety is a public health problem but no epidemiological study has been undertaken in France to evaluate its prevalence. The aim of this study was to estimate the prevalence, severity and associations of dental anxiety in a sample of the French adult population.</p> <p>Methods</p> <p>A convenience sample of 2725 adults (mean age = 47 years, SD16, minimum = 16, maximum = 101 years), representative of the French population with regard to age and urban distribution, completed a French version of the Corah Dental Anxiety scale (DAS) and a questionnaire relating to their dental appointments.</p> <p>Results</p> <p>Moderate dental anxiety (14≥DAS≥13) was revealed for 172 persons (6.2%), while 195 (7.3%) had severe dental anxiety (DAS≥15), giving an overall prevalence of dental anxiety of 13.5%. Prevalence was lower proportionally with age (P < 0.001) and was higher in French overseas territories and in the countryside (P < 0.01). Farmers and low skilled workers were significantly more anxious than executives and shopkeepers (P < 0.001). Anxiety was associated with avoidance of care (p < 0.001) and lack of regular dental appointments (p < 0.001).</p> <p>Conclusion</p> <p>Dental anxiety in France appears to concern a similar proportion of the population as in other industrialised European, Australasian or North American countries. Recommendations for prevention and management of dental anxiety are made with reference to dental education and health care services in France.</p
Survey of molecular methods for the typing of wine yeast strains
A survey of the genetic polymorphisms produced by distinct methods was performed in 23 commercial winery yeast strains. The microsatellite typing, using 6 different loci, an optimized interdelta sequence analysis and RFLP of mitochondrial DNA generated by the enzyme Hinf I had the same discriminatory power: among the 23 commercial yeast strains, 21 distinct patterns were obtained. Karyotype analysis originated 22 patterns, thereby allowing the discrimination of one of the three strains that were not distinguished by the other methods. Due to the equivalence of the results obtained in this survey, any of the methods can be applied at the industrial scale.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/BIO/38106/2001 (Eixo 2, Medida 2.3, QCAIII - FEDER).Instituto de Cooperação Científica e Tecnológica Internacional (ICCTI) - grant nº 657 C2.Comunidade Europeia (UE) - contract number QLK4-CT-2001-51873
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