3,610 research outputs found
The effect of high-speed power training on physical frailty in older adults: Effect of a visual-guided exercise program in South Korean rural areas
Objective. Exercise has been shown to be an effective intervention; the difficulty still lies in providing exercise programs to the older adults in rural areas. Therefore, this study aimed to examine the effects of a 12-week exercise program provided with visual guidelines (prerecorded video) on frailty among older adults in rural areas. Methods. Fifty participants (71.7 ± 4.9 years) from 5 different rural areas were recruited and divided into two groups: the exercise group (EX, n = 24 (male: 8, female: 18)) and the control group (CON, n = 26 (male: 7, female: 17)). With the commencement of the exercise intervention, a prerecorded high-speed power training program for frail older adults was distributed to the EX group. A new prerecorded exercise program was delivered to the EX group every 4 weeks. Frailty status was diagnosed with Fried’s criteria before and after the intervention. Muscle strength was measured in the upper and lower limb strength (hand-grip strength and leg extension and flexion), and physical function was measured using a short physical performance battery and gait speed. Fasting blood was collected before and after the intervention and analyzed for blood lipid profile. Results. After 12 weeks of the intervention period, a significant difference in frailty status () and score () favoring the EX group was observed. Physical functions (gait speed () and time for sit to stand ()) were significantly improved in the EX group with a significant increase in knee extensor strength (). A significant difference in serum high-density lipoprotein levels favoring the EX group () was also observed. Conclusions. This study confirmed the positive effect of a visual-guided exercise program on older adults’ residents in rural areas and provided alternative methods to effectively provide exercise program for the older adults with limited resources
Hall Effect of La2/3(Ca,Pb)1/3MnO3 Single Crystals near the Critical Temperature
The Hall resistivity rho_{xy} of a La_{2/3}(Ca,Pb)_{1/3}MnO_3 single crystal
has been measured as a function of temperature and field. The overall behavior
is similar to that observed previously in thin-films. At 5 K, rho_{xy} is
positive and linear in field, indicating that the anomalous contribution
is negligible. However, the effective carrier density in a free electron model
is n_{eff}=2.4 holes/Mn, even larger than the 0.85-1.9 holes/Mn reported for
thin-films and far larger than the 0.33 holes/Mn expected from the doping
level. As temperature increases, a strong, negative contribution to rho_{xy}
appears, that we ascribe to R_S. Using detailed magnetization data, we separate
the ordinary (\propto B) and anomalous (\propto M) contributions. Below T_C,
R_S \propto rho_{xx}, indicating that magnetic skew scattering is the dominant
mechanism in the metallic ferromagnetic regime. At and above the
resistivity-peak temperature, we find that rho_{xy}/rho_{xx}M is a constant,
independent of temperature and field. This implies that the anomalous Hall
coefficient is proportional to the magnetoresistance. A different explanation
based on two fluid model is also presented.Comment: revtex, 11 pages, 4 figure
Motion of b-quark inside B meson: the Parton Model vs. the ACCMM Model
We study the distribution function of the b-quark for inclusive semileptonic
B decays in the framework of the parton model. We compare the functional
behavior of the fragmentation inspired function and the Gaussian ACCMM
function, and discuss their validity. Using the HQET parameters, we can
critically test these models.Comment: 24 pages, ReVTex with 6 eps figure files embedded with epsfig.sty the
1st revised version, to appear in Phys. Rev.
Mesoscale magnetism at the grain boundaries in colossal magnetoresistive films
We report the discovery of mesoscale regions with distinctive magnetic
properties in epitaxial LaSrMnO films which exhibit
tunneling-like magnetoresistance across grain boundaries. By using
temperature-dependent magnetic force microscopy we observe that the mesoscale
regions are formed near the grain boundaries and have a different Curie
temperature (up to 20 K {\it higher}) than the grain interiors. Our images
provide direct evidence for previous speculations that the grain boundaries in
thin films are not magnetically and electronically sharp interfaces. The size
of the mesoscale regions varies with temperature and nature of the underlying
defect.Comment: 4 pages of text, 4 figure
Non-Universal Power Law of the "Hall Scattering Rate" in a Single-Layer Cuprate Bi_{2}Sr_{2-x}La_{x}CuO_{6}
In-plane resistivity \rho_{ab}, Hall coefficient, and magnetoresistance (MR)
are measured in a series of high-quality Bi_{2}Sr_{2-x}La_{x}CuO_{6} crystals
with various carrier concentrations, from underdope to overdope. Our crystals
show the highest T_c (33 K) and the smallest residual resistivity ever reported
for Bi-2201 at optimum doping. It is found that the temperature dependence of
the Hall angle obeys a power law T^n with n systematically decreasing with
increasing doping, which questions the universality of the Fermi-liquid-like
T^2 dependence of the "Hall scattering rate". In particular, the Hall angle of
the optimally-doped sample changes as T^{1.7}, not as T^2, while \rho_{ab}
shows a good T-linear behavior. The systematics of the MR indicates an
increasing role of spin scattering in underdoped samples.Comment: 4 pages, 5 figure
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