414 research outputs found
Fat Modulates the Relationship between Sarcopenia and Physical Function in Nonobese Older Adults
It is intuitive to think that sarcopenia should be associated with declines in physical function though recent evidence questions this assertion. This study investigated the relationship between absolute and relative sarcopenia, with physical performance in 202 nonobese (mean BMI = 26.6 kg/ht2) community-dwelling older (mean age = 73.8 ± 5.9
years) adults. While absolute sarcopenia (appendicular skeletal mass (ASM)/ht2) was either not associated, or weakly associated with physical performance, relative sarcopenia (ASM/kg) demonstrated moderate (r = 0.31 to r = 0.51, P < 0.01) relationships with performance outcomes in both males and females. Knee extension strength (r = 0.27) and leg extension power (r = 0.41) were both related to absolute sarcopenia (P < 0.001) in females and not in males. Strength and power were associated with relative sarcopenia in both sexes (from r = 0.47 to r = 0.67, P < 0.001). The ratio of lean mass to total body mass, that is, relative sarcopenia, is an important consideration relative to physical function in older adults even in the absence of obesity. Stratifying these individuals into equal tertiles of total body fat revealed a trend of diminished regression coefficients across each incrementally higher fat grouping for performance measures, providing further evidence that total body fat modulates the relationship between sarcopenia and physical function
Non-Destructive Identification of Cold and Extremely Localized Single Molecular Ions
A simple and non-destructive method for identification of a single molecular
ion sympathetically cooled by a single laser cooled atomic ion in a linear Paul
trap is demonstrated. The technique is based on a precise determination of the
molecular ion mass through a measurement of the eigenfrequency of a common
motional mode of the two ions. The demonstrated mass resolution is sufficiently
high that a particular molecular ion species can be distinguished from other
equally charged atomic or molecular ions having the same total number of
nucleons
Deterministic spatio-temporal control of nano-optical fields in optical antennas and nano transmission lines
We show that pulse shaping techniques can be applied to tailor the ultrafast
temporal response of the strongly confined and enhanced optical near fields in
the feed gap of resonant optical antennas (ROAs). Using finite-difference
time-domain (FDTD) simulations followed by Fourier transformation, we obtain
the impulse response of a nano structure in the frequency domain, which allows
obtaining its temporal response to any arbitrary pulse shape. We apply the
method to achieve deterministic optimal temporal field compression in ROAs with
reduced symmetry and in a two-wire transmission line connected to a symmetric
dipole antenna. The method described here will be of importance for experiments
involving coherent control of field propagation in nanophotonic structures and
of light-induced processes in nanometer scale volumes.Comment: 5 pages, 5 figure
Optimizing the Stark-decelerator beamline for the trapping of cold molecules using evolutionary strategies
We demonstrate feedback control optimization for the Stark deceleration and
trapping of neutral polar molecules using evolutionary strategies. In a
Stark-decelerator beamline pulsed electric fields are used to decelerate OH
radicals and subsequently store them in an electrostatic trap. The efficiency
of the deceleration and trapping process is determined by the exact timings of
the applied electric field pulses. Automated optimization of these timings
yields an increase of 40 % of the number of trapped OH radicals.Comment: 7 pages, 4 figures (RevTeX) (v2) minor corrections (v3) no changes to
manuscript, but fix author list in arXiv abstrac
Epitaxy and magnetotransport of Sr_2FeMoO_6 thin films
By pulsed-laser deposition epitaxial thin films of Sr_2FeMoO_6 have been pre-
pared on (100) SrTiO_3 substrates. Already for a deposition temperature of 320
C epitaxial growth is achieved. Depending on deposition parameters the films
show metallic or semiconducting behavior. At high (low) deposition temperature
the Fe,Mo sublattice has a rock-salt (random) structure. The metallic samples
have a large negative magnetoresistance which peaks at the Curie temperature.
The magnetic moment was determined to 4 mu_B per formula unit (f.u.), in
agreement with the expected value for an ideal ferrimagnetic arrangement. We
found an ordinary Hall coefficient of -6.01x10^{-10} m^3/As at 300 K,
corresponding to an electronlike charge-carrier density of 1.3 per Fe,Mo-pair.
In the semiconducting films the magnetic moment is reduced to 1 mu_B/f.u. due
to disorder in the Fe,Mo sublattice. In low fields an anomalous holelike
contribution dominates the Hall voltage, which vanishes at low temperatures for
the metallic films only.Comment: Institute of Physics, University of Mainz, Germany, 4 pages,
including 5 pictures and 1 Table, submitted to Phys. Rev.
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