4,509 research outputs found
Multi-dimensional view of quality of life amongst the elderly in Seoul, Korea
Never before in human history have so many people lived to be old. Korea like many countries has been experiencing the rapid growth of its elderly population. However in Korea, little research has been undertaken in regard to this group. This thesis aims at contributing to a better knowledge of the elderly in Korea, especially of their quality of life. The thesis examines the relationships between the quality of life determinants and life satisfaction amongst the Korean elderly with special reference to activities. Quality of life determinants include socio-economic status, health, environment, and cultural value which serve as independent variables. Activity, an intervening variable, is disaggregated into three types: group, informal, and leisure. Life satisfaction is conceptualised as a global sense of subjective well-being which does not represent any specific life concern. The field research for the study was carried out in four different areas of Seoul, Korea, selected on the basis of their contrasting residential land value. Data was collected from four different but complementary sources: archival records, 285 representative interviews using a structured questionnaire, 30 in-depth interviews with a sample of individuals over 60 years old, and 4 in-depth interviews with social workers. In this research greater participation in leisure activities amongst the Korean elderly was found to be positively correlated with their increased life satisfaction. The descending order of variables which have relatively significant influence on leisure activities and life satisfaction is cultural value, economic status, health, and environment. However, sociodemographic variables such as age, gender and educational level do not have any significant impact
Observation of Topologically Stable 2D Skyrmions in an Antiferromagnetic Spinor Bose-Einstein Condensate
We present the creation and time evolution of two-dimensional Skyrmion
excitations in an antiferromagnetic spinor Bose-Einstein condensate. Using a
spin rotation method, the Skyrmion spin textures were imprinted on a sodium
condensate in a polar phase, where the two-dimensional Skyrmion is
topologically protected. The Skyrmion was observed to be stable on a short time
scale of a few tens of ms but to have dynamical instability to deform its shape
and eventually decay to a uniform spin texture. The deformed spin textures
reveal that the decay dynamics involves breaking the polar phase inside the
condensate without having topological charge density flow through the boundary
of the finite-sized sample. We discuss the possible formation of half-quantum
vortices in the deformation process.Comment: 5 pages, 5 figure
Evidence for a preformed Cooper pair model in the pseudogap spectra of a Ca10(Pt4As8)(Fe2As2)5 single crystal with a nodal superconducting gap
For high-Tc superconductors, clarifying the role and origin of the pseudogap
is essential for understanding the pairing mechanism. Among the various models
describing the pseudogap, the preformed Cooper pair model is a potential
candidate. Therefore, we present experimental evidence for the preformed Cooper
pair model by studying the pseudogap spectrum observed in the optical
conductivity of a Ca10(Pt4As8)(Fe2As2)5 (Tc = 34.6 K) single crystal. We
observed a clear pseudogap structure in the optical conductivity and observed
its temperature dependence. In the superconducting (SC) state, one SC gap with
a gap size of {\Delta} = 26 cm-1, a scattering rate of 1/{\tau} = 360 cm-1 and
a low-frequency extra Drude component were observed. Spectral weight analysis
revealed that the SC gap and pseudogap are formed from the same Drude band.
This means that the pseudogap is a gap structure observed as a result of a
continuous temperature evolution of the SC gap observed below Tc. This provides
clear experimental evidence for the preformed Cooper pair model.Comment: 15 pages, 4 figure
Relaxation of superfluid turbulence in highly oblate Bose-Einstein condensates
We investigate thermal relaxation of superfluid turbulence in a highly oblate
Bose-Einstein condensate. We generate turbulent flow in the condensate by
sweeping the center region of the condensate with a repulsive optical
potential. The turbulent condensate shows a spatially disordered distribution
of quantized vortices and the vortex number of the condensate exhibits
nonexponential decay behavior which we attribute to the vortex pair
annihilation. The vortex-antivortex collisions in the condensate are identified
with crescent-shaped, coalesced vortex cores. We observe that the
nonexponential decay of the vortex number is quantitatively well described by a
rate equation consisting of one-body and two-body decay terms. In our
measurement, we find that the local two-body decay rate is closely proportional
to , where is the temperature and is the chemical potential.Comment: 7 pages, 9 figure
Observation of a Geometric Hall Effect in a Spinor Bose-Einstein Condensate with a Skyrmion Spin Texture
For a spin-carrying particle moving in a spatially varying magnetic field,
effective electromagnetic forces can arise due to the geometric phase
associated with adiabatic spin rotation of the particle. We report the
observation of a geometric Hall effect in a spinor Bose-Einstein condensate
with a skyrmion spin texture. Under translational oscillations of the spin
texture, the condensate resonantly develops a circular motion in a harmonic
trap, demonstrating the existence of an effective Lorentz force. When the
condensate circulates, quantized vortices are nucleated in the boundary region
of the condensate and the vortex number increases over 100 without significant
heating. We attribute the vortex nucleation to the shearing effect of the
effective Lorentz force from the inhomogeneous effective magnetic field.Comment: 9 pages, 11 figure
Kinetic study for the optimization of ginsenoside Rg3 production by heat treatment of ginsenoside Rb1
AbstractBackgroundGinsenoside Rg3 is a promising anticancer agent. It is usually produced by heat treatment of ginseng, in which ginsenoside Rb1 is the major ginsenoside. A kinetic study was conducted to optimize ginsenoside Rg3 production by the heat treatment of ginsenoside Rb1.MethodsGinsenoside Rb1 was heated using an isothermal machine at 80°C and 100°C and analyzed using HPLC. The kinetic parameters were calculated from the experimental results. The activation energy was estimated and used to simulate the process. The optimized parameters of ginsenoside Rg3 production are suggested based on the simulation.ResultsThe rate constants were 0.013 h−1 and 0.073 h−1 for the degradation of ginsenosides Rb1 and Rg3 at 80°C, respectively. The corresponding rate constants at 100°C were 0.045 h−1 and 0.155 h−1. The estimated activation energies of degradation of ginsenosides Rb1 and Rg3 were 69.2 kJ/mol and 40.9 kJ/mol, respectively. The rate constants at different temperatures were evaluated using the estimated activation energies, and the kinetic profiles of ginsenosides Rb1 and Rg3 at each temperature were simulated based on the proposed kinetic model of consecutive reaction. The optimum strategies for producing ginsenoside Rg3 from ginsenoside Rb1 are suggested based on the simulation. With increased temperature, a high concentration of ginsenoside Rg3 is formed rapidly. However, the concentration decreases quickly after the reaching the maximal concentration value.ConclusionThe optimum temperature for producing ginsenoside Rg3 should be the highest temperature technically feasible below 180°C, in consideration of the cooling time. The optimum reaction time for heat treatment is 30 min
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