2,682 research outputs found
Validity of the activPAL3 activity monitor in people moderately affected by Multiple Sclerosis
Background: Walking is the primary form of physical activity performed by people with Multiple Sclerosis (MS), therefore it is important to ensure the validity of tools employed to measure walking activity. The aim of this study was to assess the criterion validity of the activPAL3 activity monitor during overground walking in people with MS.\ud
Methods: Validity of the activPAL3 accelerometer was compared to video observation in 20 people moderately affected by MS. Participants walked 20-30m twice along a straight quiet corridor at a comfortable speed.\ud
Results: Inter-rater reliability of video observations was excellent (all intraclass correlations > 0.99). The mean difference (activPAL3- mean of raters) was -4.70 ± 9.09, -4.55 s ± 10.76 and 1.11 s ± 1.11 for steps taken, walking duration and upright duration respectively. These differences represented 8.7, 10.0 and 1.8% of the mean for each measure respectively. The activPAL3 tended to underestimate steps taken and walking duration in those who walked at cadences of ≤ 38 steps/minute by 60% and 47% respectively.\ud
Discussion: The activPAL3 is valid for measuring walking activity in people moderately affected by MS. It is accurate for upright duration regardless of cadence. In participants with slow walking cadences, outcomes of steps taken and walking duration should be interpreted with caution
Angular dependent vortex pinning mechanisms in YBCO coated conductors and thin films
We present a comparative study of the angular dependent critical current
density in YBa2Cu3O7 films deposited on IBAD MgO and on single crystal MgO and
SrTiO3 substrates. We identify three angular regimes where pinning is dominated
by different types of correlated and uncorrelated defects. We show that those
regimes are present in all cases, indicating that the pinning mechanisms are
the same, but their extension and characteristics are sample dependent,
reflecting the quantitative differences in texture and defect density. In
particular, the more defective nature of the films on IBAD turns into an
advantage as it results in stronger vortex pinning, demonstrating that the
critical current density of the films on single crystals is not an upper limit
for the performance of the IBAD coated conductors.Comment: 14 pages, 3 figures. Submitted to AP
The influence of structural defects on intra-granular critical currents of bulk MgB2
Bulk MgB2 samples were prepared under different synthesis conditions and
analyzed by scanning and transmission electron microscopy. The critical current
densities were determined from the magnetization versus magnetic field curves
of bulk and powder-dispersed-in-epoxy samples. Results show that through a slow
cooling process, the oxygen dissolved in bulk MgB2 at high synthesis
temperatures can segregate and form nanometer-sized coherent precipitates of
Mg(B,O)2 in the MgB2 matrix. Magnetization measurements indicate that these
precipitates act as effective flux pinning centers and therefore significantly
improve the intra-grain critical current density and its field dependence.Comment: 4 pages, 4 figures, to be published in IEE Transactions in Applied
Superconductivit
Soil Bacterial Diversity and Potential Functions Are Regulated by Long-Term Conservation Tillage and Straw Mulching
Soil physiochemical properties are regulated by cropping practices, but little is known
about how tillage influences soil microbial community diversity and functions. Here, we assessed
soil bacterial community assembly and functional profiles in relation to tillage. Soils, collected in
2018 from a 17‐year field experiment in northwestern China, were analyzed using high‐throughput
sequencing and the PICRUSt approach. The taxonomic diversity of bacterial communities was
dominated primarily by the phyla Proteobacteria (32–56%), Bacteroidetes (12–33%), and Actinobacteria
(17–27%). Alpha diversity (Chao1, Shannon, Simpson, and operational taxonomic unit (OTU)
richness) was highest under no‐tillage with crop residue removed (NT). Crop residue retention on
the soil surface (NTS) or incorporated into soil (TS) promoted the abundance of Proteobacteria by 16
to 74% as compared to conventional tillage (T). Tillage practices mainly affected the pathways of
soil metabolism, genetic information processing, and environmental information processing. Soil
organic C and NH4–N were the principal contributors to the diversity and composition of soil
microbiota, whereas soil pH, total nitrogen, total P, and moisture had little effect. Our results
suggest that long‐term conservation practices with no‐tillage and crop residue retention shape soil
bacterial community composition through modifying soil physicochemical properties and
promoting the metabolic function of soil microbiomes
Conservation Tillage Increases Water Use Efficiency of Spring Wheat by Optimizing Water Transfer in a Semi-Arid Environment
Water availability is a major constraint for crop production in semiarid environments.
The impact of tillage practices on water potential gradient, water transfer resistance, yield, and water
use e�ciency (WUEg) of spring wheat was determined on the western Loess Plateau. Six tillage
practices implemented in 2001 and their e�ects were determined in 2016 and 2017 including
conventional tillage with no straw (T), no-till with straw cover (NTS), no-till with no straw (NT),
conventional tillage with straw incorporated (TS), conventional tillage with plastic mulch (TP),
and no-till with plastic mulch (NTP). No-till with straw cover, TP, and NTP significantly improved
soil water potential at the seedling stage by 42, 47, and 57%, respectively; root water potential at the
seedling stage by 34, 35, and 51%, respectively; leaf water potential at the seedling stage by 37, 48,
and 42%, respectively; tillering stage by 21, 24, and 30%, respectively; jointing stage by 28, 32, and 36%,
respectively; and flowering stage by 10, 26, and 16%, respectively, compared to T. These treatments
also significantly reduced the soil–leaf water potential gradient at the 0–10 cm soil depth at the
seedling stage by 35, 48, and 35%, respectively, and at the 30–50 cm soil depth at flowering by 62,
46, and 65%, respectively, compared to T. Thus, NTS, TP, and NTP reduced soil–leaf water transfer
resistance and enhanced transpiration. Compared to T, the NTS, TP, and NTP practices increased
biomass yield by 18, 36, and 40%; grain yield by 28, 22, and 24%; and WUEg by 24, 26, and 24%,
respectively. These results demonstrate that no-till with straw mulch and plastic mulching with
either no-till or conventional tillage decrease the soil–leaf water potential gradient and soil–leaf water
transfer resistance and enhance sustainable intensification of wheat production in semi-arid areas
Gluino Contribution to the 3-loop QCD beta function in the Minimal Supersymmetric Standard Model
We deduce the gluino contribution to the three-loop QCD \beta function within
the minimal supersymmetric Standard Model (MSSM) from its standard QCD
expression. The result is a first step in the computation of the full MSSM
three-loop \beta function. In addition, in the case of a light gluino it
provides the strong three-loop SUSY correction to the extrapolation of the
strong coupling constant from the low energy regime to the Z region and up to
the squark threshold.Comment: 11 pages, RevTex, 4 Postscript figur
Kearns-sayre syndrome with reduced plasma and cerebrospinal fluid folate
A young woman with Kearns-Sayre syndrome and progressive central nervous system deterioration over 15 years had decreased plasma and cerebrospinal fluid folate levels while receiving phenytoin for a seizure disorder. A muscle biopsy showed a “ragged red fiber” myopathy with reduced muscle carnitine and mitochondrial enzymes. Computed tomographic brain scans showed cerebral white matter hypodensities and bilateral calcification of the basal ganglia. The mechanism for the folate deficiency and altered ratio of plasma to cerebrospinal fluid folate is unknown, but the deficiency may be responsive to replacement therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50301/1/410130620_ftp.pd
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