417 research outputs found
Direct and indirect orthotic management of medial compartment osteoarthritis of the knee
Osteoarthritis (OA) is a painful condition and affects approximately 80% of individuals by the age of 55 [1], with knee OA occurring two times more frequently than OA of the hand or hip [2].The condition is more prevalent in the medial compartment and restricts the daily lives of individuals due to pain and a lack of functional independence. Patients with medial compartment osteoarthritis often have a varus alignment, with the mechanical axis and load bearing passing through this compartment with a greater adduction moment leading to greater pain and progression of osteoarthritis [3]. Surgery for the condition is possible although in some cases, particularly younger patients or those not yet requiring surgery, clinical management remains a challenge. Before surgery is considered, however, conservative management is advocated, though no one treatment has been shown to be most effective, and there are few quality biomechanical or clinical studies. Of the conservative approaches the principal orthotic treatments are valgus knee braces and laterally wedged foot inlays. Studies of knee valgus bracing have consistently demonstrated an associated decreased pain and improved function [4], and greater confidence [5]. A laterally wedged foot inlay has a thicker lateral border and applies a valgus moment to the heel. It is theorised that by changing the position of the ankle and subtalar joints during weight-bearing [6] the lateral wedges may apply a valgus moment across the knee as well as the rearfoot, with the assumed reduction on load in the medial knee compartment [7]. However, there has been no study to directly compare these orthotic treatments in the same study. The aim of this research is to investigate the efficacy of valgus knee braces and laterally wedged foot inlays in reducing the varus knee moment
Gravitational Waves from Neutron Stars with Large Toroidal B-fields
We show that NS's with large toroidal B-fields tend naturally to evolve into
potent gravitational-wave (gw) emitters. The toroidal field B_t tends to
distort the NS into a prolate shape, and this magnetic distortion can easily
dominate over the oblateness ``frozen into'' the NS crust. An elastic NS with
frozen-in B-field of this magnitude is clearly secularly unstable: the wobble
angle between the NS's angular momentum J^i and the star's magnetic axis n_B^i
grow on a dissipation timescale until J^i and n_B^i are orthogonal. This final
orientation is clearly the optimal one for gravitational-wave (gw) emission.
The basic cause of the instability is quite general, so we conjecture that the
same final state is reached for a realistic NS. Assuming this, we show that for
LMXB's with B_t of order 10^{13}G, the spindown from gw's is sufficient to
balance the accretion torque--supporting a suggestion by Bildsten. The spindown
rates of most millisecond pulsars can also be attributed to gw emission sourced
by toroidal B-fields, and both these sources could be observed by LIGO II.
While the first-year spindown of a newborn NS is most likely dominated by em
processes, reasonable values of B_t and the (external) dipolar field B_d can
lead to detectable levels of gw emission, for a newborn NS in our own galaxy.Comment: 7 pages; submitted to PRD; only minor revision
Recommended from our members
Bremsstrahlung Versus Monoenergetic Photon Dose and Photonuclear Stimulation Comparisons at Long Standoff Distances
Energetic photon sources with energies greater than 6 MeV continue to be recognized as viable source for various types of inspection applications, especially those related to nuclear and/or explosive material detection. These energetic photons can be produced as a continuum of energies (i.e., bremsstrahlung distribution) or as a set of one or more discrete photon energies (i.e., monoenergetic distribution). This paper will provide a follow-on extension of the photon dose comparison presented at the 9th International Conference on Applications of Nuclear Techniques (June 2008). The latter paper showed the comparative advantages and disadvantages of the photon doses provided by these two energetic interrogation sources and highlighted the higher energy advantage of the bremsstrahlung source, especially at long standoff distances (i.e., distance from source to the inspected object). Specifically, this paper will pursue this higher energy photon inspection advantage (up to 100 MeV) by providing dose and stimulated photonuclear interaction predictions for air and an infinitely dilute interrogated material (used for comparative interaction rate assessments since it excludes material self-shielding) as the interrogation object positioned forward on the inspection beam axis at increasing standoff distances. In addition to the direct energetic photon-induced stimulation, the predictions will identify the importance of any secondary downscattered/attenuated source-term effects arising from the photon transport in the intervening atmosphere. *Supported in part by the Defense Threat Reduction Agency and Department of Energy (DOE) Idaho Operations Office under Contract Number DE-AC07-05ID14517
de Sitter String Vacua from Supersymmetric D-terms
We propose a new mechanism for obtaining de Sitter vacua in type IIB string
theory compactified on (orientifolded) Calabi-Yau manifolds similar to those
recently studied by Kachru, Kallosh, Linde and Trivedi (KKLT). dS vacuum
appears in KKLT model after uplifting an AdS vacuum by adding an anti-D3-brane,
which explicitly breaks supersymmetry. We accomplish the same goal by adding
fluxes of gauge fields within the D7-branes, which induce a D-term potential in
the effective 4D action. In this way we obtain dS space as a spontaneously
broken vacuum from a purely supersymmetric 4D action. We argue that our
approach can be directly extended to heterotic string vacua, with the dilaton
potential obtained from a combination of gaugino condensation and the D-terms
generated by anomalous U(1) gauge groups.Comment: 17 pages, 1 figur
FGF receptor genes and breast cancer susceptibility: results from the Breast Cancer Association Consortium
Background:Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.
Methods:Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.
Results:Little evidence of association with breast cancer risk was observed for SNPs in the FGF receptor genes. The strongest evidence in European women was for rs743682 in FGFR3; the estimated per-allele odds ratio was 1.05 (95 confidence interval=1.02-1.09, P=0.0020), which is substantially lower than that observed for SNPs in FGFR2.
Conclusion:Our results suggest that common variants in the other FGF receptors are not associated with risk of breast cancer to the degree observed for FGFR2. ĂŠ 2014 Cancer Research UK
Inclusive eta' Production from the Upsilon(1S)
Using the CLEO II detector at CESR, we measure the eta' - gluon - gluon
form-factor in Y(1S) decays. This form-factor especially at large eta' energies
may provide an explanation of the large rate for B -> Xs eta'. Our data do not
support a large anomalous coupling at higher q^2 and thus the large eta' rate
remains a mystery, possibly requiring a non-Standard Model explanation.Comment: 14 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Gabor Feature Based Sparse Representation for Face Recognition with Gabor Occlusion Dictionary
11th European Conference on Computer Vision, Heraklion, Crete, Greece, 5-11 Sep. 2010By coding the input testing image as a sparse linear combination of the training samples via l1-norm minimization, sparse representation based classification (SRC) has been recently successfully used for face recognition (FR). Particularly, by introducing an identity occlusion dictionary to sparsely code the occluded portions in face images, SRC can lead to robust FR results against occlusion. However, the large amount of atoms in the occlusion dictionary makes the sparse coding computationally very expensive. In this paper, the image Gabor-features are used for SRC. The use of Gabor kernels makes the occlusion dictionary compressible, and a Gabor occlusion dictionary computing algorithm is then presented. The number of atoms is significantly reduced in the computed Gabor occlusion dictionary, which greatly reduces the computational cost in coding the occluded face images while improving greatly the SRC accuracy. Experiments on representative face databases with variations of lighting, expression, pose and occlusion demonstrated the effectiveness of the proposed Gabor-feature based SRC (GSRC) scheme.Department of ComputingRefereed conference pape
The role of melanin pathways in extremotolerance and virulence of <em>Fonsecaea</em> revealed by <em>de novo</em> assembly transcriptomics using illumina paired-end sequencing
AbstractMelanisation has been considered to be an important virulence factor of Fonsecaea monophora. However, the biosynthetic mechanisms of melanisation remain unknown. We therefore used next generation sequencing technology to investigate the transcriptome and digital gene expression data, which are valuable resources to better understand the molecular and biological mechanisms regulating melanisation in F. monophora. We performed de novo transcriptome assembly and digital gene expression (DGE) profiling analyses of parent (CBS 122845) and albino (CBS 125194) strains using the Illumina RNA-seq system. A total of 17â352 annotated unigenes were found by BLAST search of NR, Swiss-Prot, Gene Ontology, Clusters of Orthologous Groups and Kyoto Encyclopedia of Genes and Genomes (KEGG) (E-value <1eâ5). A total of 2â283 unigenes were judged to be the differentially expressed between the two genotypes. We identified most of the genes coding for key enzymes involved in melanin biosynthesis pathways, including polyketide synthase (pks), multicopper oxidase (mco), laccase, tyrosinase and homogentisate 1,2-dioxygenase (hmgA). DEG analysis showed extensive down-regulation of key genes in the DHN pathway, while up-regulation was noted in the DOPA pathway of the albino mutant. The transcript levels of partial genes were confirmed by real time RT-PCR, while the crucial role of key enzymes was confirmed by either inhibitor or substrate tests in vitro. Meanwhile, numbers of genes involved in light sensing, cell wall synthesis, morphology and environmental stress were identified in the transcriptome of F. monophora. In addition, 3â353 SSRs (Simple Sequence Repeats) markers were identified from 21â600 consensus sequences. Blocking of the DNH pathway is the most likely reason of melanin deficiency in the albino strain, while the production of pheomelanin and pyomelanin were probably regulated by unknown transcription factors on upstream of both pathways. Most of genes involved in environmental tolerance to oxidants, irradiation and extreme temperatures were also assembled and annotated in transcriptomes of F. monophora. In addition, thousands of identified cSSR (combined SSR) markers will favour further genetic linkage studies. In conclusion, these data will contribute to understanding the regulation of melanin biosynthesis and help to improve the studies of pathogenicity of F. monophora
- âŚ