666 research outputs found
Survivorship in International Chain Restaurant in Korea
Several western chains have done well in Korea, while others have withdrawn from the market. The authors summarize the current operational results of western chain restaurants in Korea, report positive impacts of western foodservice firms, and analyze the key elements leading to their survival and non-survival. Some lessons could be used as tools to establish entrance strategies of western chain restaurants in Korea as well as in other Asian market
A constraint on the formation timescale of the young open cluster NGC 2264: Lithium abundance of pre-main sequence stars
The timescale of cluster formation is an essential parameter in order to
understand the formation process of star clusters. Pre-main sequence (PMS)
stars in nearby young open clusters reveal a large spread in brightness. If the
spread were considered as a result of a real spread in age, the corresponding
cluster formation timescale would be about 5 -- 20 Myr. Hence it could be
interpreted that star formation in an open cluster is prolonged for up to a few
tens of Myr. However, difficulties in reddening correction, observational
errors, and systematic uncertainties introduced by imperfect evolutionary
models for PMS stars, can result in an artificial age spread. Alternatively, we
can utilize Li abundance as a relative age indicator of PMS star to determine
the cluster formation timescale. The optical spectra of 134 PMS stars in NGC
2264 have been obtained with MMT/Hectochelle. The equivalent widths have been
measured for 86 PMS stars with a detectable Li line (3500 < T_eff [K] <= 6500).
Li abundance under the condition of local thermodynamic equilibrium (LTE) was
derived using the conventional curve of growth method. After correction for
non-LTE effects, we find that the initial Li abundance of NGC 2264 is A(Li) =
3.2 +/- 0.2. From the distribution of the Li abundances, the underlying age
spread of the visible PMS stars is estimated to be about 3 -- 4 Myr and this,
together with the presence of embedded populations in NGC 2264, suggests that
the cluster formed on a timescale shorter than 5 Myr.Comment: 53 pages, 12 figures, 4 tables, Accepted for publication in the
Astrophysical Journa
Sejong Open Cluster Survey (SOS) - IV. The Young Open Clusters NGC 1624 and NGC 1931
Young open clusters located in the outer Galaxy provide us with an
opportunity to study star formation activity in a different environment from
the solar neighborhood. We present a UBVI and H alpha photometric study of the
young open clusters NGC 1624 and NGC 1931 that are situated toward the Galactic
anticenter. Various photometric diagrams are used to select the members of the
clusters and to determine the fundamental parameters. NGC 1624 and NGC 1931
are, on average, reddened by = 0.92 +/- 0.05 and 0.74 +/- 0.17 mag,
respectively. The properties of the reddening toward NGC 1931 indicate an
abnormal reddening law (Rv,cl = 5.2 +/- 0.3). Using the zero-age main sequence
fitting method we confirm that NGC 1624 is 6.0 +/- 0.6 kpc away from the Sun,
whereas NGC 1931 is at a distance of 2.3 +/- 0.2 kpc. The results from
isochrone fitting in the Hertzsprung-Russell diagram indicate the ages of NGC
1624 and NGC 1931 to be less than 4 Myr and 1.5 - 2.0 Myr, respectively. We
derived the initial mass function (IMF) of the clusters. The slope of the IMF
(Gamma_NGC 1624 = -2.0 +/- 0.2 and Gamma_NGC 1931 = -2.0 +/- 0.1) appears to be
steeper than that of the Salpeter/Kroupa IMF. We discuss the implication of the
derived IMF based on simple Monte-Carlo simulations and conclude that the
property of star formation in the clusters seems not to be far different from
that in the solar neighborhood.Comment: 79 pages, 21 pages, 7 tables, Accepted for publication in the
Astronomical Journa
Prevalence of Metabolic Syndrome according to Sasang Constitutional Medicine in Korean Subjects
Metabolic syndrome (MS) is a complex disorder defined by a cluster of abdominal obesity, atherogenic dyslipidemia, hyperglycemia, and hypertension; the condition is recognized as a risk factor for diabetes and cardiovascular disease. This study assessed the effects of the Sasang constitution group (SCG) on the risk of MS in Korean subjects. We have analyzed 1,617 outpatients of Korean oriental medicine hospitals who were classified into three SCGs, So-Yang, So-Eum, and Tae-Eum. Significant differences were noted in the prevalence of MS and the frequencies of all MS risk factors among the three SCGs. The odds ratios for MS as determined via multiple logistic regression analysis were 2.004 for So-Yang and 4.521 for Tae-Eum compared with So-Eum. These results indicate that SCG may function as a significant risk factor of MS; comprehensive knowledge of Sasang constitutional medicine may prove helpful in predicting susceptibility and developing preventive care techniques for MS
Sejong Open Cluster Survey (SOS). 0. Target Selection and Data Analysis
Star clusters are superb astrophysical laboratories containing cospatial and
coeval samples of stars with similar chemical composition. We have initiated
the Sejong Open cluster Survey (SOS) - a project dedicated to providing
homogeneous photometry of a large number of open clusters in the SAAO
Johnson-Cousins' system. To achieve our main goal, we have paid much
attention to the observation of standard stars in order to reproduce the SAAO
standard system.
Many of our targets are relatively small, sparse clusters that escaped
previous observations. As clusters are considered building blocks of the
Galactic disk, their physical properties such as the initial mass function, the
pattern of mass segregation, etc. give valuable information on the formation
and evolution of the Galactic disk. The spatial distribution of young open
clusters will be used to revise the local spiral arm structure of the Galaxy.
In addition, the homogeneous data can also be used to test stellar evolutionary
theory, especially concerning rare massive stars. In this paper we present the
target selection criteria, the observational strategy for accurate photometry,
and the adopted calibrations for data analysis such as color-color relations,
zero-age main sequence relations, Sp - Mv relations, Sp - Teff relations, Sp -
color relations, and Teff - BC relations. Finally we provide some data analysis
such as the determination of the reddening law, the membership selection
criteria, and distance determination.Comment: 21 pages, 16 figures, accepted for publication in J. of Korean
Astronomical Society (JKAS
Association of the Apolipoprotein A5 Gene −1131T>C Polymorphism with Serum Lipids in Korean Subjects: Impact of Sasang Constitution
Apolipoprotein A5 (APOA5) was identified as a strong modulator of serum lipids. Moreover, an APOA5 gene −1131T>C polymorphism has been associated with serum lipids, but the results are inconsistent according to ethnic and racial groups. We have genotyped and analyzed 1,619 outpatients of Korean oriental medicine hospitals who were classified into three Sasang constitution groups (SCGs), So-Yang (SY), So-Eum (SE), and Tae-Eum (TE). There were no significant difference in the distribution of the APOA5 −1131T>C genotype among the three SCGs. Subjects with the C allele in SY and TE showed significantly lower serum high-density lipoprotein cholesterol (HDL-C) and higher triglyceride (TG) levels than noncarriers of the C allele. These results show the differences in the prevalence of decreasing serum HDL-C and elevating serum TG levels along with APOA5 −1131T>C polymorphism according to SCG and suggest that SCG may act as a significant risk factor for hypo-HDL-C-emia and hypertriglyceridemia susceptibility
Application examples of a very economic way of cellular sprayed concrete on retaining wall and artificial rock
An economic slope structure construction method for landscape was developed, which utilized the cellular sprayed concrete for high performance shotcrete. This can improve the performance of shotcrete material, maximize the construction advantages of shotcrete and further harmonize with the surrounding environment. This may solve various problems such as efficient slope stabilization of large-scale slopes from natural disasters that occur annually due to climate change, the necessity of disaster prevention and restoration technologies, existing slope maintenance and reinforcement construction methods for weathering. This construction method maximizes the economic feasibility by manufacturing a high-performance cellular shotcrete using an ordinary ready mixed concrete and concrete pump car. Cellular shotcrete is produced by incorporating cellular and mineral admixtures in the process of remixing and dispersing the mineral admixture in an ordinary ready mixed concrete at a job site. High strength and high durability are secured by using high-performance cellular shotcrete without using accelerators. Speed and safety are improved by adopting a concrete pump car reaching a far way on the slope without formwork in the top-down and bottom-up method. In addition, this technique can highlight nature-friendly scenery since it is a construction method that comprehends natural rock shapes and colors, by carving various natural rock patterns on the placed high-performance shotcrete before the thickness is adjusted and before it hardens. After curing for a certain period of time, a coloring agent like stain is sprayed on the surface to develop color by neutralization reaction
Sejong open cluster survey (SOS) - III. The young open cluster NGC 1893 in the H II region W8
We present a UBVI and Hα photometric study of the young open cluster NGC 1893 in the HII region W8 (IC 410 or Sh 2-236). A total of 65 early-type members are selected from photometric diagrams. A mean reddening of the stars is = 0.563 ± 0.08
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