484 research outputs found
Examining sex differences in knee pain: the Multicenter Osteoarthritis Study
SummaryObjectiveTo determine whether women experience greater knee pain severity than men at equivalent levels of radiographic knee osteoarthritis (OA).Design and methodsA cross-sectional analysis of 2712 individuals (60% women) without knee replacement or a recent steroid injection. Sex differences in pain severity at each KellgrenâLawrence (KL) grade were assessed by knee using visual analog scale (VAS) scale and Western Ontario and McMaster Universities Arthritis Index (WOMAC) with and without adjustment for age, analgesic use, Body mass index (BMI), clinic site, comorbid conditions, depression score, education, race, and widespread pain (WSP) using generalized estimating equations. Effect sizes (Cohen's d) were also calculated. Analyses were repeated in those with and without patellofemoral OA (PFOA).ResultsWomen reported higher VAS pain at all KL grades in unadjusted analyses (d = 0.21â0.31, P < 0.0001â0.0038) and in analyses adjusted for all covariates except WSP (d = 0.16â0.22, P < 0.0001â0.0472). Pain severity differences further decreased with adjustment for WSP (d = 0.10â0.18) and were significant for KL grade â€2 (P = 0.0015) and 2 (P = 0.0200). Presence compared with absence of WSP was associated with significantly greater knee pain at all KL grades (d = 0.32â0.52, P < 0.0001â0.0008). In knees with PFOA, VAS pain severity sex differences were greater at each KL grade (d = 0.45â0.62, P = 0.0006â0.0030) and remained significant for all KL grades in adjusted analyses (d = 0.31â0.57, P = 0.0013â0.0361). Results using WOMAC were similar.ConclusionsWomen reported greater knee pain than men regardless of KL grade, though effect sizes were generally small. These differences increased in the presence of PFOA. The strong contribution of WSP to sex differences in knee pain suggests that central sensitivity plays a role in these differences
Polar phonons in some compressively stressed epitaxial and polycrystalline SrTiO3 thin films
Several SrTiO3 (STO) thin films without electrodes processed by pulsed laser
deposition, of thicknesses down to 40 nm, were studied using infrared
transmission and reflection spectroscopy. The complex dielectric responses of
polar phonon modes, particularly ferroelectric soft mode, in the films were
determined quantitatively. The compressed epitaxial STO films on (100)
La0.18Sr0.82Al0.59-Ta0.41O3 substrates (strain 0.9%) show strongly stiffened
phonon responses, whereas the soft mode in polycrystalline film on (0001)
sapphire substrate shows a strong broadening due to grain boundaries and/or
other inhomogeneities and defects. The stiffened soft mode is responsible for a
much lower static permittivity in the plane of the compressed film than in the
bulk samples.Comment: 11 page
Electric current circuits in astrophysics
Cosmic magnetic structures have in common that they are anchored
in a dynamo, that an external driver converts kinetic energy into internal
magnetic energy, that this magnetic energy is transported as Poynting fl ux across the magnetically dominated structure, and that the magnetic energy
is released in the form of particle acceleration, heating, bulk motion,
MHD waves, and radiation. The investigation of the electric current system is
particularly illuminating as to the course of events and the physics involved.
We demonstrate this for the radio pulsar wind, the solar flare, and terrestrial
magnetic storms
Phase Transitions of Hard Disks in External Periodic Potentials: A Monte Carlo Study
The nature of freezing and melting transitions for a system of hard disks in
a spatially periodic external potential is studied using extensive Monte Carlo
simulations. Detailed finite size scaling analysis of various thermodynamic
quantities like the order parameter, its cumulants etc. are used to map the
phase diagram of the system for various values of the density and the amplitude
of the external potential. We find clear indication of a re-entrant liquid
phase over a significant region of the parameter space. Our simulations
therefore show that the system of hard disks behaves in a fashion similar to
charge stabilized colloids which are known to undergo an initial freezing,
followed by a re-melting transition as the amplitude of the imposed, modulating
field produced by crossed laser beams is steadily increased. Detailed analysis
of our data shows several features consistent with a recent dislocation
unbinding theory of laser induced melting.Comment: 36 pages, 16 figure
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
change
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
Observation of hard scattering in photoproduction events with a large rapidity gap at HERA
Events with a large rapidity gap and total transverse energy greater than 5
GeV have been observed in quasi-real photoproduction at HERA with the ZEUS
detector. The distribution of these events as a function of the
centre of mass energy is consistent with diffractive scattering. For total
transverse energies above 12 GeV, the hadronic final states show predominantly
a two-jet structure with each jet having a transverse energy greater than 4
GeV. For the two-jet events, little energy flow is found outside the jets. This
observation is consistent with the hard scattering of a quasi-real photon with
a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Clustering Algorithms: Their Application to Gene Expression Data
Gene expression data hide vital information required to understand the biological process that takes place in a particular organism in relation to its environment. Deciphering the hidden patterns in gene expression data proffers a prodigious preference to strengthen the understanding of functional genomics. The complexity of biological networks and the volume of genes present increase the challenges of comprehending and interpretation of the resulting mass of data, which consists of millions of measurements; these data also inhibit vagueness, imprecision, and noise. Therefore, the use of clustering techniques is a first step toward addressing these challenges, which is essential in the data mining process to reveal natural structures and iden-tify interesting patterns in the underlying data. The clustering of gene expression data has been proven to be useful in making known the natural structure inherent in gene expression data, understanding gene functions, cellular processes, and subtypes of cells, mining useful information from noisy data, and understanding gene regulation. The other benefit of clustering gene expression data is the identification of homology, which is very important in vaccine design. This review examines the various clustering algorithms applicable to the gene expression data in order to discover and provide useful knowledge of the appropriate clustering technique that will guarantee stability and high degree of accuracy in its analysis procedure
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