Malignancies in Korean Patients with Inflammatory Myopathy

The aim of this study was to assess the prevalence and the common type of malignancies in Korean patients with polymyositis (PM) and dermatomyositis (DM) and to evaluate the differences of clinical and laboratory findings between patients with malignancy and those without malignancy. Forty-one Korean patients, who were diagnosed as PM or DM, were enrolled in this study. They fulfilled the Bohan and Peter's criteria for a definite diagnosis of PM and DM. Patients with PM were 25 and those with DM were 16. Eleven out of 41 patients (26.8%) had malignancies. The malignancy was diagnosed simultaneously or later in 81.8% of patients with inflammatory myopathy (IM). The breast cancer was the most common malignancy. In this study, forty three years old as a screening age for malignancy had 88.9% sensitivity and 50.2% specificity. The serum levels of creatine kinase (CK) were significantly lower in patients with malignancy than those without malignancy

Quantitative Analysis on the Energy and Environmental Impact of the Korean National Energy R&D Roadmap a Using Bottom-Up Energy System Model

According to the Paris Agreement at the 21st Conference of the Parties, 196 member states are obliged to submit their Intended Nationally Determined Contributions (INDC) for every 5 years. As a member, South Korea has already proposed the reduction target and need to submit the achievement as a result of the policies and endeavors in the near future. In this paper, a Korean bottom-up energy system model to support the low-carbon national energy R&D roadmap will be introduced and through the modeling of various scenarios, the mid-to long-term impact on energy consumptions and CO2 emissions will be analyzed as well. The results of the analysis showed that, assuming R&D investments for the 11 types of technologies, savings of 13.7% with regards to final energy consumptions compared to the baseline scenario would be feasible by 2050. Furthermore, in the field of power generation, the generation proportion of new and renewable energy is expected to increase from 3.0% as of 2011 to 19.4% by 2050. This research also suggested that the analysis on the Energy Technology R&D Roadmap based on the model can be used not only for overall impact analysis and R&D portfolio establishment, but also for the development of detailed R&D strategies.1100Ysciessciscopu

Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions

We study the Hubbard-Holstein model, which includes both the electron-electron and electron-phonon interactions characterized by $U$ and $g$, respectively, employing the dynamical mean-field theory combined with Wilson's numerical renormalization group technique. A zero temperature phase diagram of metal-insulator and insulator-insulator transitions at half-filling is mapped out which exhibits the interplay between $U$ and $g$. As $U$ ($g$) is increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition occurs, and the two insulating states are distinct and can not be adiabatically connected. The nature of and transitions between the three states are discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter

The structure and formation of business groups: Evidence from Korean Chaebols

In this paper we study the determinants of business groups’ ownership structure using a unique dataset of Korean chaebols, and a set of new metrics of group ownership structure. We find that chaebols grow vertically (that is, pyramidally) as the family uses well-established group firms (“central firms”) to set up and acquire firms that have low profitability and high capital requirements. Chaebols grow horizontally (that is, using direct family ownership) when the family acquires firms that are highly profitable and require less capital. We also provide direct evidence that the low profitability of firms owned through pyramids is partly due to a selection effect: the profitability of new group firms in the year before they are added to the group predicts whether they are added to pyramids or controlled directly by the family. The relationships between pyramids, profitability, and capital intensity that we uncover do not appear to be due to the separation between ownership and control induced by pyramids. Finally, we find that the selection of low-profitability firms into pyramids causes the group’s central firms to trade at a discount relative to other public group firms. Taken together, these results suggest that controlling families optimally design the ownership structure of the group in a manner that is consistent with theory

Inter- and Intra-Annual Variability of Vegetation in the Northern Hemisphere and Its Association with Precursory Meteorological Factors

Determination of phenological variation is one of the most critical challenges in dynamic vegetation modeling, given the lack of a strong theoretical framework. Previous studies generally focused on the timing of a phenological event (e.g., bud-burst or onset of growing season) and its atmospheric prompts, but not on the interactive variations across phenological stages. This study, therefore, investigated the inter- and intra-annual variability existing in all the phenological stages and the relations of the variability with four meteorological variables (surface temperature (Ts), shortwave radiation (SW ), vapor pressure deficit (VPD), and precipitation (PRCP)) using a 25-year (1982-2006) dataset of leaf area index (LAI) from the Advanced Very High Resolution Radiometer (AVHRR). Our six study sites of each 4 degree x 4 degree grids (mixed forest in China, deciduous needle-leaf forest in Siberia, evergreen needle-leaf forest in western Canada, grass in Gobi, and crops in the Central United States and southeastern Europe) include various vegetation types, local climates, and land-use types in the mid-latitudes of the northern hemisphere. Empirical orthogonal function (EOF) analysis with detrended LAI anomalies identified the two leading EOF modes that account for the amplitude and phase of the monthly LAI variations. The inter-annual correlation between the principle components (PCs) of the two modes and the meteorological variables for spring and summer showed that the amplitude and phase modes (AM and PM, respectively) were affected by different dominant meteorological factors. Over most of the study regions, AM was positively correlated with PRCP and negatively with Ts, SW, and VPD,while PMwas predominantly positively correlated with Ts. The contrasting responses of the two EOFmodes to Ts reflect environmental limitations on plant growth such as early start of growth, but with a reduced value of maximum LAI in a year with a warm spring. In addition, insignificant correlations between AMand PRCP, as well as negative correlations between PM and PRCP, in the crop regions suggest that human interventions such as advanced irrigation systems also play a key role in vegetative activity

I-gel as a first-line airway device in the emergency room for patients with out-of-hospital cardiac arrest

Aim. The optimal method for advanced airway management during cardiac arrest remains controversial. Most patients with out-of-hospital cardiac arrest (OHCA) in Korea are managed with a bag-valve mask by paramedics, while physicians perform advanced airway management in emergency departments (ED). Endotracheal intubation (ETI) has a risk of failure at the first attempt. By contrast, I-gel, a supraglottic airway device, is easier to insert than an endotracheal tube and shows a higher first-attempt success rate than ETI in out-of-hospital settings by paramedics in the United States. We reviewed the use of ETI and I-gel by ED physicians to assess the first attempt success rate in a hospital setting. Methods. We conducted a retrospective chart review of patients with non-traumatic OHCA who were managed with either ETI using a Macintosh laryngoscope, or I-gel in the ED of Korean hospital from January 2012 to January 2014. Results. Of 322 adult patients with non-traumatic OHCA, 160 received I-gel and 162 received ETI. The first-attempt success rate was higher in the I-gel group (96.9%) than in the ETI group (84.6%, p < 0.001). The time from arrival to obtaining advanced airway management was shorter in the I-gel group than in the ETI group. Conclusions. I-gel showed a better first-attempt success rate and shorter insertion time compared with ETI when performed by physicians in a hospital setting

The Structure and Formation of Business Groups: Evidence from Korean Chaebols

In this paper we study the determinants of business groups' ownership structure using unique panel data on Korean chaebols. In particular, we attempt to understand how pyramids form over time. We find that chaebols grow vertically (that is, pyramidally) as the family uses well-established group firms ("central firms") to set up and acquire younger firms that have low profitability and high capital requirements. Chaebols grow horizontally (that is, using direct family ownership) when the family acquires firms that are highly profitable and require less capital. Our evidence suggests that the (previously documented) lower profitability of pyramidal firms is partly due to a selection effect (e.g., the family optimally places low profitability firms in pyramids). To show this, we examine instances of large changes in the ownership structure of group firms. Specifically, we find that poor past performance predicts an increase in the degree of pyramiding in a firm's ownership structure. Most compellingly, we find that the profitability of new group firms in the year before they are added to the group predicts whether they are added to pyramids or controlled directly by the family. We also examine the relative valuation of chaebol firms. We find that the group's central firms trade at a discount relative to other public group firms possibly due to the selection of low-profitability, high capital intensity firms into pyramids. Our results shed light on the process by which pyramids form, and provide new evidence on the performance and valuation of business group firms.