968 research outputs found
Dissipate locally, couple globally: a sharp transition from decoupling to infinite range coupling in Josephson arrays with on-site dissipation
We study the T=0 normal to superconducting transition of Josephson arrays
with {\it on-site} dissipation. A perturbative renormalization group solution
is given. Like the previously studied case of {\it bond} dissipation (BD), this
is a "floating" to coupled (FC) phase transition. {\it Unlike} the BD
transition, at which {\it only} nearest-neighbor couplings become relevant,
here {\it all} inter-grain couplings, out to {\it infinitely} large distances,
do so simultaneously. We predict, for the first time in an FC transition, a
diverging spatial correlation length. Our results show the robustness of
floating phases in dissipative quantum systems.Comment: 7+ pages, 3 eps figures, Europhysics Letters preprint format, as
publishe
Decay of correlations in the dissipative two-state system
We study the equilibrium correlation function of the polaron-dressed
tunnelling operator in the dissipative two-state system and compare the
asymptoptic dynamics with that of the position correlations. For an Ohmic
spectral density with the damping strength , the correlation functions
are obtained in analytic form for all times at any and any bias. For ,
the asymptotic dynamics is found by using a diagrammatic approach within a
Coulomb gas representation. At T=0, the tunnelling or coherence correlations
drop as , whereas the position correlations show universal decay
. The former decay law is a signature of unscreened attractive
charge-charge interactions, while the latter is due to unscreened dipole-dipole
interactions.Comment: 5 pages, 5 figures, to be published in Europhys. Let
EFFECT OF DIFFERENT LOW BACK TRAINING PROGRAMS ON LUMBAR SPINE KINESTHESIA
Reduced kinesthetic perceptions can impair lower back sensorimotor functions and result in increased injury risk. The effect of low back training programs on lumbar spine kinesthetic sensibility is undetermined. There was a back strengthening exercise group (with low back pain; training 4.4 h/wk), a âclassicalâ back training program group (with low back pain; training 4.9 h/wk) and a control group (training 5.4 h/wk). During an active reproduction test, subjects performed trunk positions in random order: flexion [A(0°-20°), B(20°-40°)], lateral flexion [C(0°-30°)], Using a 3D-ultrasound motion analysis system the repositioning error was calculated from the given target position to the subject perceived target position, before and after a 5 week training period. Results show decreased repositioning error after the training for both training groups
TRUNK POSTURE AND STATICO-DYNAMICAL SPINE ANALYSISâ COMPARING ULTRASOUND BASED VS. OPTICALLY BASED MEASUREMENT SYSTEM
The purpose of this study was to compare two different methods measuring trunk posture and statico-dynamical spine analysis. 32 patients participated in this cross sectional study. Comparing measured values a wide congruence could be demonstrated with marginal underestimating in kyphosis and lordosis data for the ultrasound based system. The largest deviation could be shown for pelvic obliquity measured in mm. Trunk inclination, vertical deflection and pelvic obliquity measured in degree showed proper analogy for both measuring systems. Validity, reliability based on particular technical principles could be verified
CHANGES IN ISOMETRIC AND ISOKINETIC STRENGTH, POSTURAL BALANCE AND ENDURANCE AFTER THAI-BO TRAINING PROGRAM
The objective of the present study was to examine the influence of a long term Thai-Bo training program on muscular strength of the knee muscles, postural balance, and cardiovascular parameters. Thirty-five volunteers participated in two groups. Pre-and posttest with measuring of isometric and isokinetic strength of knee extension/flexion as well as postural balance on a force plate were performed before and after a weekly six-months training period. Furthermore cardiovascular parameters were measured during a stepwise increasing cycle ergometry. The results showed a significant increase of isometric strength and isokinetic strength at 600 /s in addition to an improvement in postural balance. Also a significant improvement of cardiovascular parameters in retest could be demonstrated
PLANTAR PRESSURE MEASUREMENTS IN A SOCCER SHOE: CHARACTERIZATION OF SOCCER SPECIFIC MOVEMENTS AND EFFECTS AFTER SIX WEEKS OF AGING
The purposes of the study were (i) to characterize in-shoe pressure distribution (PD) measurements during soccer specific movements, (ii) to describe the changes on (PD) after six weeks of aging. 21 experienced male subjects participated in the study. Four different movements (run, cut, sprint and goal shot) were measured on a red cinder surface before and after six weeks of aging. Results showed specific loading characteristics for each movement: Compared to running, the medial part of the foot in cutting, the forefoot in sprinting and the lateral part in kicking were predominantly loaded. Peak pressures increased over 10% after six weeks of use in some high-load areas. Attention should be paid to sprinting and cutting with respect to overuse injuries. Sockliners should be exchanged on a regular basis to maintain a certain amount of cushioning
SPECIFIC TRAINING CAN IMPROVE SENSORIMOTOR CONTROL IN TYPE 2 DIABETIC PATIENTS
Diabetes mellitus often is associated with proprioceptive and sensory deficits as a result of distal diabetic polyneuropathy (DPN). The aim of this prospective controlled longitudinal trial was to evaluate a specific sport intervention program regarding sensorimotor capabilities in type 2 diabetic patients compared to healthy controls. A higher incidence of fall-related injuries is given in the literature (Allet et al.2008; Allet et al 2009)
Deployment of RDFa, Microdata, and Microformats on the Web â A Quantitative Analysis
More and more websites embed structured data describing for instance
products, reviews, blog posts, people, organizations, events, and cooking recipes
into their HTML pages using markup standards such as Microformats, Microdata
and RDFa. This development has accelerated in the last two years as major Web
companies, such as Google, Facebook, Yahoo!, and Microsoft, have started to
use the embedded data within their applications. In this paper, we analyze the
adoption of RDFa, Microdata, and Microformats across the Web. Our study is
based on a large public Web crawl dating from early 2012 and consisting of 3
billion HTML pages which originate from over 40 million websites. The analysis
reveals the deployment of the different markup standards, the main topical areas
of the published data as well as the different vocabularies that are used within each
topical area to represent data. What distinguishes our work from earlier studies,
published by the large Web companies, is that the analyzed crawl as well as the
extracted data are publicly available. This allows our ïŹndings to be veriïŹed and to
be used as starting points for further domain-speciïŹc investigations as well as for
focused information extraction endeavors
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Influence of annealing on microstructure and mechanical properties of ultrafine-grained Ti45Nb
Beta-Ti alloys have been intensively investigated in the last years because of their favorable low Young's moduli, biocompatibility and bio-inertness, making these alloys interesting candidates for implant materials. Due to their low mechanical strength, efforts are currently devoted to increasing it. A promising way to improve the strength is to tailor the microstructure using severe plastic deformation (SPD). In this investigation high pressure torsion was used to refine the microstructure of a Ti-45wt.%Nb alloy inducing a grain size of ~50âŻnm. The main focus of the subsequent investigations was devoted to the thermal stability of the microstructure. Isochronal heat-treatments performed for 30âŻmin in a temperature range up to 500âŻÂ°C caused an increase of hardness with a peak value at 300âŻÂ°C before the hardness decreased at higher temperatures. Simultaneously, a distinct temperature-dependent variation of the Young's modulus was also measured. Tensile tests revealed an increase in strength after annealing compared to the SPD-state. Microstructural investigations showed that annealing causes the formation of α-Ti. The findings suggest that the combination of severe plastic deformation with subsequent heat treatment provides a feasible way to improve the mechanical properties of SPD-deformed ÎČ-Ti alloys making them suitable for higher strength applications
Comparative genomics in chicken and Pekin duck using FISH mapping and microarray analysis
BACKGROUND:
The availability of the complete chicken (Gallus gallus) genome sequence as well as a large number of chicken probes for fluorescent in-situ hybridization (FISH) and microarray resources facilitate comparative genomic studies between chicken and other bird species. In a previous study, we provided a comprehensive cytogenetic map for the turkey (Meleagris gallopavo) and the first analysis of copy number variants (CNVs) in birds. Here, we extend this approach to the Pekin duck (Anas platyrhynchos), an obvious target for comparative genomic studies due to its agricultural importance and resistance to avian flu.
RESULTS:
We provide a detailed molecular cytogenetic map of the duck genome through FISH assignment of 155 chicken clones. We identified one inter- and six intrachromosomal rearrangements between chicken and duck macrochromosomes and demonstrated conserved synteny among all microchromosomes analysed. Array comparative genomic hybridisation revealed 32 CNVs, of which 5 overlap previously designated "hotspot" regions between chicken and turkey.
CONCLUSION:
Our results suggest extensive conservation of avian genomes across 90 million years of evolution in both macro- and microchromosomes. The data on CNVs between chicken and duck extends previous analyses in chicken and turkey and supports the hypotheses that avian genomes contain fewer CNVs than mammalian genomes and that genomes of evolutionarily distant species share regions of copy number variation ("CNV hotspots"). Our results will expedite duck genomics, assist marker development and highlight areas of interest for future evolutionary and functional studies
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