4,758 research outputs found
Concentrated suspensions of Brownian beads in water: dynamic heterogeneities trough a simple experimental technique
Concentrated suspensions of Brownian hard-spheres in water are an epitome for
understanding the glassy dynamics of both soft materials and supercooled
molecular liquids. From an experimental point of view, such systems are
especially suited to perform particle tracking easily, and, therefore, are a
benchmark for novel optical techniques, applicable when primary particles
cannot be resolved. Differential Variance Analysis (DVA) is one such novel
technique that simplifies significantly the characterization of structural
relaxation processes of soft glassy materials, since it is directly applicable
to digital image sequences of the sample. DVA succeeds in monitoring not only
the average dynamics, but also its spatio-temporal fluctuations, known as
dynamic heterogeneities. In this work, we study the dynamics of dense
suspensions of Brownian beads in water, imaged through digital
video-microscopy, by using both DVA and single-particle tracking. We focus on
two commonly used signatures of dynamic heterogeneities: the dynamic
susceptibility, , and the non-Gaussian parameter, . By direct
comparison of these two quantities, we are able to highlight similarities and
differences. We do confirm that and provide qualitatively
similar information, but we find quantitative discrepancies in the scalings of
characteristic time and length scale on approaching the glass transition.Comment: The original publication is available at http://www.scichina.com and
http://www.springerlink.com
http://engine.scichina.com/publisher/scp/journal/SCPMA/doi/10.1007/s11433-019-9401-x?slug=abstrac
Smoking and Psoriasis: From Epidemiology to Pathomechanisms
Smoking is a well-established environmental risk factor for psoriasis. It should be carefully considered in genetic studies because smoking can modify risk estimates for genetic markers. Genome-wide association studies may facilitate the analysis of genetic–environmental interaction in psoriasis
On off-shell bosonic string amplitudes
We give a simple prescription for computing, in the framework of the bosonic
string theory, off-shell one-loop amplitudes with any number of external
massless particles, both for the open and for the closed string. We discuss
their properties and, in particular, for the two-string one-loop amplitudes we
show their being transverse.Comment: 12 pages, Latex. One reference added. Introduction and conclusions
expanded. Some other minor changes in the tex
Experimental Response of Connections Between Cold-formed Steel Profile and Cememnt-based Panel
The seismic response of sheathed cold-f
ormed steel (CFS) structures is highly
influenced by the shear behaviour of panel-to-steel framing connections.
Therefore, an experimental campai
gn aiming at characterizing the shear
behaviour of different sheathing-to-CFS profiles connections has been planed. In
particular, the following objectives have
been selected: to co
mpare the response
of different panel typologies (cement, wood and gypsum–based panels); to
examine the effect of the
loaded edge distance; to
investigate the outcome of
different cyclic loading protocols. This paper presents and discusses the main
results of this experimental investigation carried out on cement-based sheathing-
to-stud connections
Experimental Response of Connections Between Cold-formed Steel Profile and Cememnt-based Panel
Value of tongue biting in the differential diagnosis between epileptic seizures and syncope
AbstractBackgroundTongue biting (TB) may occur both in epileptic seizures and in syncope. A comprehensive search of the literature to determine the accuracy of this physical finding and its prevalence in epileptic seizures and syncope is still lacking.AimsTo undertake a systematic review and a meta-analysis of studies evaluating the prevalence of TB in patients with epileptic seizures and syncope, and to determine sensitivity, specificity and likelihood ratios (LR) of this physical finding.MethodStudies comparing the prevalence of TB in epileptic seizures and syncope were systematically searched. Prevalence of TB was analyzed calculating odds ratio (OR) with 95% confidence intervals (CIs). Sensitivity, specificity, positive and negative likelihood ratio (pLR, nLR) of TB were determined for each study and for the pooled results.ResultsTwo studies (75 epilepsy patients and 98 subjects with syncope) were included. There was a significantly higher prevalence of TB in patients with epileptic seizures (OR 12.26; 95% CI 3.99–37.69). Pooled accuracy measures of TB for the diagnosis of epileptic seizures were: sensitivity 33%, specificity 96%, pLR 8.167 (95% CI 2.969–22.461) and nLR 0.695 (95% CI 0.589–0.82).ConclusionsA pooled analysis of data from the literature shows that TB has great value in the differential diagnosis between epileptic seizures and syncope. Given a certain pre-test probability of seizures, the presence of TB greatly increases the chance that the patient had an epileptic seizure. Systematic reviews with pooled analyses (meta-analyses) of data from the literature allow an increase in statistical power and an improvement in precision, representing a useful tool to determine the accuracy of a certain physical finding in the differential diagnosis between seizures and other paroxysmal events
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