2,315 research outputs found
Optical Characterization of Elastohydrodynamic Lubrication Pressure with Surface Plasmon Resonance
De Sitter Thermodynamics from Diamonds's Temperature
The thermal time hypothesis proposed by Rovelli [1] regards the physical
basis for the flow of time as thermodynamical and provides a definition of the
temperature for some special cases. We verify this hypothesis in the case of de
Sitter spacetime by relating the uniformly accelerated observer in de Sitter
spacetime to the diamond in Minkowski spacetime. Then, as an application of it,
we investigate the thermal effect for the uniformly accelerated observer with a
finite lifetime in dS spacetime, which generalizes the corresponding result for
the case of Minkowski spacetime [2].
Furthermore, noticing that a uniformly accelerated dS observer with a finite
lifetime corresponds to a Rindler observer with a finite lifetime in the
embedding Minkowski spacetime, we show that the
global-embedding-Minkowski-spacetime (GEMS) picture of spacetime thermodynamics
is valid in this case. This is a rather nontrivial and unexpected
generalization of the GEMS picture, as well as a further verification of both
the thermal time hypothesis and the GEMS picture.Comment: 10 pages, 3 figures, LaTeX; v2: reorganized with a new section added
concerning a generalization of the GEMS picture from our result; v3: version
with minor corrections, to appear in JHE
D-optimal designs via a cocktail algorithm
A fast new algorithm is proposed for numerical computation of (approximate)
D-optimal designs. This "cocktail algorithm" extends the well-known vertex
direction method (VDM; Fedorov 1972) and the multiplicative algorithm (Silvey,
Titterington and Torsney, 1978), and shares their simplicity and monotonic
convergence properties. Numerical examples show that the cocktail algorithm can
lead to dramatically improved speed, sometimes by orders of magnitude, relative
to either the multiplicative algorithm or the vertex exchange method (a variant
of VDM). Key to the improved speed is a new nearest neighbor exchange strategy,
which acts locally and complements the global effect of the multiplicative
algorithm. Possible extensions to related problems such as nonparametric
maximum likelihood estimation are mentioned.Comment: A number of changes after accounting for the referees' comments
including new examples in Section 4 and more detailed explanations throughou
Measure representation and multifractal analysis of complete genomes
This paper introduces the notion of measure representation of DNA sequences.
Spectral analysis and multifractal analysis are then performed on the measure
representations of a large number of complete genomes. The main aim of this
paper is to discuss the multifractal property of the measure representation and
the classification of bacteria. From the measure representations and the values
of the spectra and related curves, it is concluded that these
complete genomes are not random sequences. In fact, spectral analyses performed
indicate that these measure representations considered as time series, exhibit
strong long-range correlation. For substrings with length K=8, the
spectra of all organisms studied are multifractal-like and sufficiently smooth
for the curves to be meaningful. The curves of all bacteria
resemble a classical phase transition at a critical point. But the 'analogous'
phase transitions of chromosomes of non-bacteria organisms are different. Apart
from Chromosome 1 of {\it C. elegans}, they exhibit the shape of double-peaked
specific heat function.Comment: 12 pages with 9 figures and 1 tabl
Peculiarities of sub-barrier fusion with quantum diffusion approach
With the quantum diffusion approach the unexpected behavior of fusion cross
section, angular momentum, and astrophysical S-factor at sub-barrier energies
has been revealed. Out of the region of short-range nuclear interaction and
action of friction at turning point the decrease rate of the cross section
under the barrier becomes smaller. The calculated results for the reactions
with spherical nuclei are in a good agreement with the existing experimental
data.Comment: 11 pages, 5 figure
Interaction of CO2 laser-modified nylon with osteoblast cells in relation to wettability
It has been amply demonstrated previously that CO2 lasers hold the ability to surface modify various polymers. In addition, it has been observed that these surface enhancements can augment the biomimetic nature of the laser irradiated materials. This research has employed a CO2 laser marker to produce trench and hatch topographical patterns with peak heights of around 1 ÎŒm on the surface of nylon 6,6. The patterns generated have been analysed using white light interferometery, optical microscopy and X-ray photoelectron spectroscopy was employed to determine the surface oxygen content. Contact angle measurements were used to characterize each sample in terms of wettability. Generally, it was seen that as a result of laser processing the contact angle, surface roughness and surface oxygen content increased whilst the apparent polar and total surface energies decreased. The increase in contact angle and reduction in surface energy components was found to be on account of a mixed intermediate state wetting regime owing to the change in roughness due to the induced topographical patterns. To determine the biomimetic nature of the modified and as-received control samples each one was seeded with 2Ă104 cells/ml normal human osteoblast cells and observed after periods of 24 hours and 4 days using optical microscopy and SEM to determine mean cell cover densities and variations in cell morphology. In addition a haeymocytometer was used to show that the cell count for the laser patterned samples had increased by up to a factor of 1.5 compared to the as-received control sample after 4 days of incubation. Significantly, it was determined that all laser-induced patterns gave rise to better cell response in comparison to the as-received control sample studied due to increased preferential cell growth on those surfaces with increased surface roughness
Two-to-one resonant multi-modal dynamics of horizontal/inclined cables. Part I : theoretical formulation and model validation
This paper is first of the two papers dealingwith analytical investigation of resonant multimodal dynamics due to 2:1 internal resonances in the finite-amplitude free vibrations of horizontal/inclined cables. Part I deals with theoretical formulation and validation of the general cable model. Approximate nonlinear partial differential equations of 3-D coupled motion of small sagged cables - which account for both spatio-temporal variation of nonlinear dynamic tension and system asymmetry due to inclined sagged configurations - are presented. A multidimensional Galerkin expansion of the solution ofnonplanar/planar motion is performed, yielding a complete set of system quadratic/cubic coefficients. With the aim of parametrically studying the behavior of horizontal/inclined cables in Part II [25], a second-order asymptotic analysis under planar 2:1 resonance is accomplished by the method of multiple scales. On accounting for higher-order effectsof quadratic/cubic nonlinearities, approximate closed form solutions of nonlinear amplitudes, frequencies and dynamic configurations of resonant nonlinear normal modes reveal the dependence of cable response on resonant/nonresonant modal contributions. Depending on simplifying kinematic modeling and assigned system parameters, approximate horizontal/inclined cable models are thoroughly validated by numerically evaluating statics and non-planar/planar linear/non-linear dynamics against those of the exact model. Moreover, the modal coupling role and contribution of system longitudinal dynamics are discussed for horizontal cables, showing some meaningful effects due to kinematic condensation
Persistent wheeze in infants: A guide for general pediatricians
Infants with persistent wheeze is a common diagnostic challenge for the general pediatrician because of the broad differential diagnoses. The initial diagnostic approach should include a comprehensive history, physical examination, and chest radiography. Additional testing may be warranted. Involvement of a pediatric pulmonary subspecialist may also be indicated
Human Parechovirus Infections in Monkeys with Diarrhea, China
Information about human parechovirus (HPeV) infection in animals is scant. Using 5âČ untranslated region reverse transcriptionâPCR, we detected HPeV in feces of monkeys with diarrhea and sequenced the complete genome of 1 isolate (SH6). Monkeys may serve as reservoirs for zoonotic HPeV transmissions and as models for studies of HPeV pathogenesis
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