4,872 research outputs found
Direct and Indirect Detection of Neutralino Dark Matter and Collider Signatures in an Model with Two Intermediate Scales
We investigate the detectability of neutralino Dark Matter via direct and
indirect searches as well as collider signatures of an model with two
intermediate scales. We compare the direct Dark Matter detection cross section
and the muon flux due to neutralino annihilation in the Sun that we obtain in
this model with mSUGRA predictions and with the sensitivity of current and
future experiments. In both cases, we find that the detectability improves as
the model deviates more from mSUGRA. In order to study collider signatures, we
choose two benchmark points that represent the main phenomenological features
of the model: a lower value of and reduced third generation sfermion
masses due to extra Yukawa coupling contributions in the Renormalization Group
Equations, and increased first and second generation slepton masses due to new
gaugino loop contributions. We show that measurements at the LHC can
distinguish this model from mSUGRA in both cases, by counting events containing
leptonically decaying bosons, heavy neutral Higgs bosons, or like--sign
lepton pairs.Comment: 21 pages, 16 figure
Development of KAISTSAT-4 Expanding the Role of Small Satellite for Scientific Research
The fourth Korean small satellite, KAISTSAT-4, is under development by Satellite Technology Research Center (SaTReC) of the Korea Advanced Institute of Science and Technology (KAIST). The KAISTSAT-4 program was commenced on October 1998 with multiple mission objectives, which include exploring space science, deploying satellite-based data collection system and development of precision star sensor. Despite severe constraints on mass and size, these advanced science and engineering payloads are expected to deliver various useful results and exhibit the unique role of small satellite. We present an overview of the KAISTSAT-4 mission and describe its current status. Finally the prospect of future small satellite programs is briefly introduced
Staphylococcal enterotoxin sensitization in a community-based population : a potential role in adult-onset asthma
Background: Recent studies suggest that Staphylococcus aureus enterotoxin sensitization is a risk factor for asthma. However, there is a paucity of epidemiologic evidence on adult-onset asthma in community-based populations.
Objective: We sought to evaluate the epidemiology and the clinical significance of staphylococcal enterotoxin sensitization in community-based adult populations.
Methods: The present analyses were performed using the baseline data set of Korean adult population surveys, consisting of 1080 adults (mean age=60.2years) recruited from an urban and a rural community. Questionnaires, methacholine challenge tests, and allergen skin tests were performed for defining clinical phenotypes. Sera were analysed for total IgE and enterotoxin-specific IgE using ImmunoCAP.
Results: Staphylococcal enterotoxin sensitization (0.35kU/L) had a prevalence of 27.0%. Risk factors were identified as male sex, current smoking, advanced age (61years), and inhalant allergen sensitization. Current asthma was mostly adult onset (18years old) and showed independent associations with high enterotoxin-specific IgE levels in multivariate logistic regression tests. In multivariate linear regressions, staphylococcal enterotoxin-specific IgE level was identified as the major determinant factor for total IgE level.
Conclusions and Clinical Relevance: Staphylococcal enterotoxin sensitization was independently associated with adult-onset asthma in adult community populations. Strong correlations between the enterotoxin-specific IgE and total IgE levels support the clinical significance. The present findings warrant further studies for the precise roles of staphylococcal enterotoxin sensitization in the asthma pathogenesis
Incidence of harmful algal blooms in pristine subtropical ocean: a satellite remote sensing approach (Jeju Island)
Despite the increasing numbers of red tide events in the pristine subtropical ocean, a paucity of previous observations has limited understanding of harmful algae in the seas around the Korean Peninsula. Therefore, using six years (2012–2017) of Geostationary Ocean Color Imager (GOCI) satellite data, we characterized the red tides around Jeju Island, a volcanic island located near the paths of the Jeju Warm Current and Tsushima Warm Current, using the Normalized Red Tide Index (NRTI) method. The seawater around Jeju Island has for a long time been considered to be very clear, with relatively low suspended particulate matter concentrations and few harmful algae. Nonetheless, the satellite-based NRTI detection method used in this study detected and supported the existence of red tides in the coastal region around Jeju Island. Analysis of the red tide distribution showed that red tide first began to appear near the western coast of Jeju Island, then developed in the northern and eastern coastal regions, and finally vanished in the eastern coastal region. The monthly averages of the NRTI demonstrated a bloom event from April to May in every year. Additional fall blooms were detected in August–September, particularly in 2013 and 2016. The NRTI revealed strong interannual variations. The longest blooms occurred in 2015, and the most comprehensive and strongest event occurred in the spring of 2016. The latter three years (2015–2017) had much higher NRTI than the former three years (2012–2014). The probability of red tide occurrence at a given point during the 6-year study period revealed spatial differences. Relatively high probability of 0.3–0.5 was determined along the northern coastal region, whereas low probability of less than 0.2 was found along the southern region. Ground truth data also showed more frequent observations and higher red tide cell densities along the northern coast. Changes in NRTI in spring are positively correlated with changes in ENSO indices in winter. This study is the first to use a satellite-based approach with a vast long-term satellite database to elucidate the existence and probability of red tides near Jeju Island. We anticipate that this study will provide a useful strategy for remote monitoring of harmful algal blooms over wide regions using optical data
Morphological Comparison of Stem Cells Using Two- Dimensional Culture and Spheroid Culture
Mesenchymal stem cells are of great interest, especially in regeneration medicine. Mesenchymal stem cells have the ability to differentiate into several tissues including bone and fat. The stem cells can be obtained from various tissues including bone marrow, periosteum, gingiva, and tooth. Traditionally, two-dimensional culture has been applied for stem cell research. However, more recently, a three-dimensional model has been of great interest for studying the stem cells because it mimics the physiological conditions. Spheroid culture is one way of applying three-dimensional culture. This report describes the two-dimensional culture and spheroid culture and the morphological comparison will be performed between two-dimensional culture and spheroid culture
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