1,284 research outputs found
In-Chain Tunneling Through Charge-Density Wave Nanoconstrictions and Break-Junctions
We have fabricated longitudinal nanoconstrictions in the charge-density wave
conductor (CDW) NbSe using a focused ion beam and using a mechanically
controlled break-junction technique. Conductance peaks are observed below the
TK and TK CDW transitions, which correspond closely
with previous values of the full CDW gaps and
obtained from photo-emission. These results can be explained by assuming
CDW-CDW tunneling in the presence of an energy gap corrugation
comparable to , which eliminates expected peak at
. The nanometer length-scales our experiments imply
indicate that an alternative explanation based on tunneling through
back-to-back CDW-normal junctions is unlikely.Comment: 5 pages, 3 figures, submitted to physical review letter
Boundary effect on CDW: Friedel oscillations, STM image
We study the effect of open boundary condition on charge density waves (CDW).
The electron density oscillates rapidly close to the boundary, and additional
non-oscillating terms (~ln(r)) appear. The Friedel oscillations survive beyond
the CDW coherence length (v_F/Delta), but their amplitude gets heavily
suppressed. The scanning tunneling microscopy image (STM) of CDW shows clear
features of the boundary. The local tunneling conductance becomes asymmetric
with respect to the Fermi energy, and considerable amount of spectral weight is
transferred to the lower gap edge. Also it exhibits additional zeros reflecting
the influence of the boundary.Comment: 7 pages, 6 figure
Deep Saturated Free Electron Laser Oscillators and Frozen Spikes
We analyze the behavior of Free Electron Laser (FEL) oscillators operating in
the deep saturated regime and point out the formation of sub-peaks of the
optical pulse. They are very stable configurations, having a width
corresponding to a coherence length. We speculate on the physical mechanisms
underlying their growth and attempt an identification with FEL mode locked
structures associated with Super Modes. Their impact on the intra-cavity
nonlinear harmonic generation is also discussed along with the possibility of
exploiting them as cavity out-coupler.Comment: 28 page
Habitual physical activity and cardiometabolic risk factors in adults with cerebral palsy
2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license(http://creativecommons.org/licenses/by/3.0/).This article has been made available through the Brunel Open Access Publishing Fund.Adults with cerebral palsy (CP) are known to participate in reduced levels of total physical activity. There is no information available however, regarding levels of moderate-to-vigorous physical activity (MVPA) in this population. Reduced participation in MVPA is associated with several cardiometabolic risk factors. The purpose of this study was firstly to compare levels of sedentary, light, MVPA and total activity in adults with CP to adults without CP. Secondly, the objective was to investigate the association between physical activity components, sedentary behavior and cardiometabolic risk factors in adults with CP. Adults with CP (n = 41) age 18â62 yr (mean ± SD = 36.5 ± 12.5 yr), classified in Gross Motor Function Classification System level I (n = 13), II (n = 18) and III (n = 10) participated in this study. Physical activity was measured by accelerometry in adults with CP and in age- and sex-matched adults without CP over 7 days. Anthropometric indicators of obesity, blood pressure and several biomarkers of cardiometabolic disease were also measured in adults with CP. Adults with CP spent less time in light, moderate, vigorous and total activity, and more time in sedentary activity than adults without CP (p < 0.01 for all). Moderate physical activity was associated with waist-height ratio when adjusted for age and sex (ÎČ = â0.314, p < 0.05). When further adjustment was made for total activity, moderate activity was associated with waist-height ratio (ÎČ = â0.538, p < 0.05), waist circumference (ÎČ = â0.518, p < 0.05), systolic blood pressure (ÎČ = â0.592, p < 0.05) and diastolic blood pressure (ÎČ = â0.636, p < 0.05). Sedentary activity was not associated with any risk factor. The findings provide evidence that relatively young adults with CP participate in reduced levels of MVPA and spend increased time in sedentary behavior, potentially increasing their risk of developing cardiometabolic disease
Werkende minima in Amsterdam. Kwalitatief onderzoek naar situatie van werkende armen in Amsterdam
In het Nederlandse armoedebeleid van de afgelopen decennia ligt een sterke nadruk op
het belang van werk als oplossing van armoede. Uitgangspunt is dat werk moet lonen en
dat een voltijdbaan in beginsel voldoende inkomen moet opleveren om als volwaardig
burger binnen de samenleving te kunnen participeren. De vraag is echter in hoeverre
werk mensen direct uit de armoede haalt. Zo verschijnen er berichten in de pers over
werkende armen in Nederland (Tinnemans 2009; Stoker 2010) en is duidelijk dat het
verschijnsel âwerkende armoedeâ niet alleen voorkomt in marginale verzorgingsstaten
zoals de Verenigde Staten (Newma
One-dimensional conduction in Charge-Density Wave nanowires
We report a systematic study of the transport properties of coupled
one-dimensional metallic chains as a function of the number of parallel chains.
When the number of parallel chains is less than 2000, the transport properties
show power-law behavior on temperature and voltage, characteristic for
one-dimensional systems.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let
Crossover from 2-dimensional to 1-dimensional collective pinning in NbSe3
We have fabricated NbSe structures with widths comparable to the
Fukuyama-Lee-Rice phase-coherence length. For samples already in the
2-dimensional pinning limit, we observe a crossover from 2-dimensional to
1-dimensional collective pinning when the crystal width is less than 1.6
m, corresponding to the phase-coherence length in this direction. Our
results show that surface pinning is negligible in our samples, and provide a
means to probe the dynamics of single domains giving access to a new regime in
charge-density wave physics.Comment: 4 pages, 2 figures, and 1 table. Accepted for publication in Physical
Review
Generation of three iPSC lines from two patients with heterozygous FOXF1 mutations associated to Alveolar Capillary Dysplasia with Misalignment of the Pulmonary Veins
Diagnosing Alveolar Capillary Dysplasia with Misalignment of the Pulmonary Veins (ACD/MPV) based on a genetic alteration in the FOXF1 gene, is complicated by the poor understanding of the causal relation between FOXF1 variants and the ACD/MPV phenotype. Here, we report the generation of human iPSC lines from two ACD/MPV patients, each carrying a different heterozygous FOXF1 mutation, which enables disease modeling for further research on the effect of FOXF1 variants in vitro. The iPSC lines were generated from skin fibroblasts using the non-integrating Sendai virus. The lines expressed pluripotency genes, retained the heterozygous mutation and were capable of trilineage differentiation
Safety of OscillatingĂą Rotating Powered Brushes Compared to Manual Toothbrushes: A Systematic Review
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141660/1/jper0005.pd
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