471 research outputs found
Motion artifact reduction using multi-channel PPG signals
A data processing device is disclosed for extracting a desired vital signal containing a physiological information component from sensor data that includes time-dependent first sensor data comprising the physiological information component and at least one motion artifact component, and that includes time-dependent second sensor data that is indicative of a position, a velocity or an acceleration of the sensed region as a function of time. A decomposition unit decomposes the second sensor data into at least two components of decomposed sensor data and, based on the decomposed second sensor data, provides at least two different sets of motion reference data in at least two different motion reference data channels. An artifact removal unit determines the vital signal formed from a linear combination of the first sensor data and the motion reference data of at least one two of the motion reference data channels.</p
Topological effects in ring polymers: A computer simulation study
Unconcatenated, unknotted polymer rings in the melt are subject to strong
interactions with neighboring chains due to the presence of topological
constraints. We study this by computer simulation using the bond-fluctuation
algorithm for chains with up to N=512 statistical segments at a volume fraction
\Phi=0.5 and show that rings in the melt are more compact than gaussian chains.
A careful finite size analysis of the average ring size R \propto N^{\nu}
yields an exponent \nu \approx 0.39 \pm 0.03 in agreement with a Flory-like
argument for the topologica interactions. We show (using the same algorithm)
that the dynamics of molten rings is similar to that of linear chains of the
same mass, confirming recent experimental findings. The diffusion constant
varies effectively as D_{N} \propto N^{-1.22(3) and is slightly higher than
that of corresponding linear chains. For the ring sizes considered (up to 256
statistical segments) we find only one characteristic time scale \tau_{ee}
\propto N^{2.0(2); this is shown by the collapse of several mean-square
displacements and correlation functions onto corresponding master curves.
Because of the shrunken state of the chain, this scaling is not compatible with
simple Rouse motion. It applies for all sizes of ring studied and no sign of a
crossover to any entangled regime is found.Comment: 20 Pages,11 eps figures, Late
Tailoring the flow of soft glasses by soft additives
We examine the vitrification and melting of asymmetric star polymers mixtures
by combining rheological measurements with mode coupling theory. We identify
two types of glassy states, a {\it single} glass, in which the small component
is fluid in the glassy matrix of the big one and a {\it double} glass, in which
both components are vitrified. Addition of small star polymers leads to melting
of {\it both} glasses and the melting curve has a non-monotonic dependence on
the star-star size ratio. The phenomenon opens new ways for externally steering
the rheological behavior of soft matter systems.Comment: 4 pages, 4 figures, accepted in Phys. Rev. Let
Polydisperse star polymer solutions
We analyze the effect of polydispersity in the arm number on the effective
interactions, structural correlations and the phase behavior of star polymers
in a good solvent. The effective interaction potential between two star
polymers with different arm numbers is derived using scaling theory. The
resulting expression is tested against monomer-resolved molecular dynamics
simulations. We find that the theoretical pair potential is in agreement with
the simulation data in a much wider polydispersity range than other proposed
potentials. We then use this pair potential as an input in a many-body theory
to investigate polydispersity effects on the structural correlations and the
phase diagram of dense star polymer solutions. In particular we find that a
polydispersity of 10%, which is typical in experimental samples, does not
significantly alter previous findings for the phase diagram of monodisperse
solutions.Comment: 14 pages, 7 figure
Self-diffusion in binary blends of cyclic and linear polymers
A lattice model is used to estimate the self-diffusivity of entangled cyclic
and linear polymers in blends of varying compositions. To interpret simulation
results, we suggest a minimal model based on the physical idea that constraints
imposed on a cyclic polymer by infiltrating linear chains have to be released,
before it can diffuse beyond a radius of gyration. Both, the simulation, and
recently reported experimental data on entangled DNA solutions support the
simple model over a wide range of blend compositions, concentrations, and
molecular weights.Comment: 10 pages, 2 figure
Vervangingsopgave natte kunstwerken in het hoofdwatersysteem en hoofdvaarwegennet in Nederland
De vervangingsopgave natte kunstwerken: een strategische opgave voor Rijkswaterstaat – Rijkswaterstaat beheert als asset manager op duurzame wijze het Nederlandse hoofdwegennet, hoofdvaarwegennet en hoofdwatersysteem. Daarbij werkt Rijkswaterstaat aan de vlotte en veilige doorstroming van het (weg- en scheepvaart)verkeer, aan een veilig, schoon en gebruikersgericht watersysteem, aan de bescherming van Nederland tegen overstromingen en aan de leefbaarheid van Nederland. Rijkswaterstaat heeft in het verleden veel geïnvesteerd in de aanleg van infrastructuur in het watersysteem (het hoofdvaarwegennet en het hoofdwatersysteem)
When to perform urodynamics before mid-urethral sling surgery for female stress urinary incontinence?
INTRODUCTION AND HYPOTHESIS: Development of a model that can predict in which group of women pre-operative urodynamics can be safely omitted. METHODS: Three hundred and eighty-one uncomplicated women who underwent pre-operative urodynamics were evaluated. A multivariate logistic regression model was developed based on medical history and physical examination predicting a high probability group of women with detrusor overactivity or a low (<20 cm H2O) mean urethral closure pressure and, therefore, are likely to benefit from urodynamics. RESULTS: Women are likely to benefit from pre-operative urodynamics if they (1) are 53 years of age or older or (2) have a history of prior incontinence surgery and are at least 29 years of age or (3) have nocturia complaints and are at least 36 years of age. CONCLUSION: If urogynaecologists omitted pre-operative urodynamics in women in the low probability group, in our population, pre-operative urodynamics would be reduced by 29
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