• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.574-587
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• 2014

In this study, vertical distribution patterns of Quercus mongolica Fisch. ex Ledeb. and Q. serrata Murray in Korea were recognized and possibility of introgressive hybridization and gene flow between Q. mongolica and Q. serrata in Mt. Jiri was inferred by flavonoid analyses. The most critical factor on distribution patterns was the altitude in accordance with temperature condition. A zonal distribution was recognized: Quercus mongolica zone in the upper area and Q. serrata zone in the lower area. In Central Korea, the range of vertical distribution of Q. mongolica was above alt. 100m, almost everywhere, whereas that of Q. serrata was from alt. 0 m to alt. 500(-700) m, and the species is rare above that altitude. But in Southern Korea, Q. serrata is found up to above alt. 1,000 m, whereas frequency of Q. mongolica reduces as elevation in decline and the species is rare below alt. 300 m, even though pure stands being formed on higher mountain slope. Altitudinal distribution of the two species, however, overlaps, where the two species occur together. Thirty-seven individuals of Q. mongolica and Q. serrata in Mt. Jiri and other area were examined for leaf flavonoid constituents. Twenty-three flavonoid compounds were isolated and identified; they were glycosylated derivatives of the flavonols kaempferol, quercetin, isorhamnetin, myricetin, and four compounds among the flavonoid compounds were acylated. Kaempferol 3-O-glucoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside and its acylated compounds were major constituents and present in all individuals. Quercus mongolica is distinguished from Q. serrata by the presence of quercetin 3-O-arabinosylglucoside and by high concentration of three acylated compounds, acylated kaempferol 3-O-glucoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside, and by relatively low concentration or lacking of rhamnosyl flavonol compounds. There are intraspecific variations in flavonoid profiles for Q. mongolica and Q. serrata, the flavonoid profiles for individuals of two species in hybrid zone (sympatric zone) tend to be similar to each other, qualitatively and quantitatively. These findings strongly suggest that gene exchange or gene flow occurs through the introgressive hybridization between Q. mongolica and Q. serrata in Mt. Jiri. Therefore, Quercus crispula, occupying morphologically intermediate position between Q. mongolica and Q. serrata, is suspected of being a hybrid taxon of two putative parental species.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.71-81
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• 2015

This study was carried out in order to investigate the mineralogical characteristics of the core sediments (03GHP-02 and HB13-2), obtained from the Ulleung Basin and Hupo Basin, Korea. The results on mineral compositions, clay mineral compositions, and the total contents and sequential extraction of different fractions of the phosphorus in core samples showed that those values are different in two cores and also at different depths. In both samples, mineral compositions were the same, composed mainly of quartz, microcline, albite, calcite, opal A, pyrite, and clay minerals (illite, chlorite, kaolinite, and smectite). However, the sample from Hupo Basin contains more opal A. Both samples, especially the ones from Hupo Basin contains more smectite than those reported from East Sea, indicating the influence of paleo-Hwangwei River and the Tertiary Formation of Korea Peninsula. For the samples from Uleung Basin, at 0.7-3.5 m range in depth, the low content of opal A and the low illite crystallinity index can be inferred to indicate the relatively cool climate, corresponding to the ice age. Also, the content of total phosphorus was low in those samples. It was reported that East Sea at that time was isolated from the neighboring seas due to the decrease of the sea level, and as a result, the influx of sediments was supposed to be little through the strait and rivers. For the samples from Hupo Basin, there is no significant changes in clay mineral composition and the distribution of phosphorus with increasing depth. This little change can be interpreted to indicate that the sediments comprising the core might be deposited in a relatively short period of time or deposited in sedimentary environment in which there's no significant changes in sediment supplies. The values of crystallinity index of clay minerals are high in those samples, indicating that it was relatively warm during that time. Although the increase of fluctuation pattern can be observed, showing that the climate of this period often changed, it is supposed that it was generally warm.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.2
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• pp.114-120
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• 2017

There have been many studies to develop methods for predicting diabetes and to prevent diabetes. The validity of glycated hemoglobin (HbA1c), one of the commonly known tools in predicting diabetes, has been verified by many previous studies. In this study, we examined the cutoff value of HbA1c for diabetes and impaired fasting glucose (IFG). Based on this study, we proposed a proper clinical guideline and evaluated the validation of the guideline. Excluding those without blood glucose and HbA1c data, we used the data of 5,161 subjects (2,281 men and 2,880 women) over the age of 20 years from the 2015 Korean National Health and Nutrition Examination Survey. The correlation efficient of fasting plasma glucose (FPG) and HbA1c was 0.79, indicating a strong relationship. Howeve, the correlation efficient of FPG and HbA1c was low, showing 0.27 in non-diabetes, 0.39 in IFG, and 0.66 in diabetes, showing a strong relationship. The cutoff value of HbA1c for predicting diabetes using ROC curve was 6.05% (sensitivity 84.6%, and specificity 92.0%), and AUC was 0.941 (0.937 in men, and 0.946 in women). The cutoff value of HbA1c for predicting IFG using ROC curve was 5.55% (sensitivity 64.5%, and specificity 70.0%), and AUC was 0.733 (0.708 in men, and 0.764 in women). Therefore, it may not be appropriate to apply the guidelines for diagnosing IFG since sensitivity and specificity were below 70%. For future studies retarding the cutoff value of HbA1c in predicting IFG, high sensitivity and specificity are expected if we segment the reference range of IFG.

• Journal of Nutrition and Health
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• v.48 no.4
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• pp.335-343
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• 2015

Purpose: The aim of this study was to evaluate the food behavior and nutritional status of elementary school students in the Jeju area using Nutrition Quotient (NQ). Methods: The subjects were 440 students (235 boys and 205 girls) in the fifth and sixth grade at four elementary schools located in Jeju. Demographic, lifestyle, and environmental information was collected using a self-reported questionnaire. The food behavior checklist for children's Nutrition Quotient (NQ), consisting of 19 items, and nutrition education related information were also obtained. Results: The mean score of the children's NQ was poor, reaching 60.3 points. The percentage distribution of NQ grade was 19.8% (lowest), 18.6% (low), 45.0% (medium), 10.7% (high), and 5.9% (highest) and the factor scores for balance, diversity, abstinence, regularity, and practice were 56.6, 68.4, 71.3, 57.4, and 54.8 points, respectively. Compared with the NQ cut-off points for defining malnutrition (balance; 57, diversity; 87, abstinence; 66, regularity; 69, and practice; 67 point), average score of abstinence factor was only above the cut-off point and scores of the other factors were below the cut-off point. Subjects with higher NQ scores tended to have higher levels of exercise activity (p < 0.001), frequency of family meals (p < 0.01), and father's educational levels (p < 0.01) compared to those with lower NQ score. NQ score showed positive association with nutrition education experience and practice (p < 0.001). Conclusion: NQ score of elementary school students residing in Jeju was lower than the national average. More opportunities should be provided for participation in nutrition education, which incorporates a range of program strategies, as well as communication and education activities.

• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.469-477
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• 2018

Hanabusaya asiatica is an endemic species whose distribution is limited in the mid-eastern part of the Korean peninsula. Due to its narrow range and small population, it is necessary to protect its habitats by identifying it as Key Biodiversity Areas (KBAs) adopted by the International Union for Conservation of Nature (IUCN). In this paper, we estimated potential natural habitats for H. asiatica using maximum entropy model (MaxEnt) and identified candidate sites for KBA based on the model results. MaxEnt is a machine learning algorithm that can predict habitats for species of interest unbiasedly with presence-only data. This property is particularly useful for the study area where data collection via a field survey is unavailable. We trained MaxEnt using 38 locations of H. asiatica and 11 environmental variables that measured climate, topography, and vegetation status of the study area which encompassed all locations of the border region between South and North Korea. Results showed that the potential habitats where the occurrence probabilities of H. asiatica exceeded 0.5 were $778km^2$, and the KBA candidate area identified by taking into account existing protected areas was $1,321km^2$. Of 11 environmental variables, elevation, annual average precipitation, average precipitation in growing seasons, and the average temperature in the coldest month had impacts on habitat selection, indicating that H. asiatica prefers cool regions at a relatively high elevation. These results can be used not only for identifying KBAs but also for the reference to a protection plan for H. asiatica in preparation of Korean reunification and climate change.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.229-236
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• 2018

The aim of this study was to evaluate the genetic diversity and relationships of Ogye populations in Korea. A total of 243 genomic DNA samples from 6 Ogye population (Yeonsan Ogye; YSO, Animal Genetic Resources Research Center Ogye; ARO, Chungbuk Ogye; CBO, Chungnam Ogye; CNO, Gyeongbuk Ogye; GBO, Seoul National University Ogye; SUO) and 3 introduced chicken breeds (Rhode Island Red; RIR, White Leghorn; LG, Cornish; CN) were used. Sizes of 25 microsatellite markers were decided using GeneMapper Software(v 5.0) after analyzing ABI 3130XL. A total of 153 alleles were observed and the range was 2 to 10 per each locus. The mean of expected and observed heterozygosity and PIC (Polymorphism Information Content) value was 0.53, 0.50, 0.46 respectively. The lowest genetic distance (0.073) was observed between YSO and SUO, and the highest distance (0.937) between the RIR and CBO. The results of clustering analysis suggested 3 clusters (${\Delta}K=7.96$). Excluding GBO population, 5 Ogye populations (YSO, ARO, CBO, CNO, SUO) were grouped in same cluster with high genetic uniformity (0.990, 0.979, 0.989, 0.994, 0.985 respectively). But GBO population was grouped in cluster 1 with low genetic uniformity (0.340). The results of this study can be use to basic data for the genetic evaluation and management of Ogye populations in Korea.

• Korean Journal of Environment and Ecology
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• v.34 no.1
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• pp.18-26
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• 2020

Echinosophora koreensis (Nakai) Nakai an endemic plant with limited distribution in some parts of the Korean Peninsula, is designated as "Endangered" species on the IUCN Red List. The species is under the threat of deterioration in nature due to various environmental changes causing loss of natural habitats. We investigated the distribution pattern and population structure of E. koreensis to serve as a basic reference for identifying the dynamics and persistence of natural populations of this species in the future. To determine the characteristics of the E. koreensis population, we laid two to three large plots sized 20m×30m on the ridgeline as the reference in Yanggu, Chuncheon, and Hongcheon and laid four to seven small quadrats sized 1m×1m on the transect. A total of 530 plots were laid, 10 each at 2m interval, to measure the number of the stems, the number of fruiting, height, and other factors. The collected distribution information was compared with the existing IUCN assessed categories by applying IUCN Red List ver 3.1 Criteria B. The average population density of the three surveyed areas was 3.47 stem/㎡; the density of each area was 3.95 stems/㎡ in Yanggu, 3.37 stems/㎡ in Chuncheon, and 2.87 stems/㎡ in Hongcheon. The number of fruiting per stem was 0.0038, indicating only 7 fruits out of 1,837 stems and that vegetative reproduction is likely to be more dominant than sexual reproduction. The distribution tendency of population density in the small plots in three surveyed areas showed that the density of E. koreensis tended to decrease toward the center of the forest with low crown openness and around the mountain ridge with high crown openness. It indicated that the quantity of light could be a very important factor for the growth of individuals of this species. The analysis of the heights of individuals present in the surveyed plots showed a range of 2.3 ~ 68.5cm and an average of 20.1cm. An analysis on the stage-structure of the E. koreensis population based on the sieve height found that the appearance frequency decreased with increasing height above 15 ~ 20cm and that the percentage of individuals lower than 10cm, which were presumed to be seedlings, was severely low, indicating a necessity of study on the population sustainability based on the monitored data. The occupied area calculated with the collected species distribution information was 200㎢, indicating the EN category according to the IUCN Red List Reference B.

• Strategy21
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• s.34
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• pp.58-92
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• 2014

Even after S. Korea took 5.24 Measure(24 May 2014), N. Korea has not stopped raising provocations such as the shelling of Yeonpyeong Island, electronic and cyber attacks. To make matters worse, the communist country lunched long-range missiles(twice) and conducted 3rd nuclear test, escalating tensions which could possibly lead to an all-out war. Korean Government failed to respond properly. However, escalation into an all-out war was deterred by the CFC immediately carrying out its peacetime duty(CODA). The US made a rapid dispatch of its augmentation forces(Aircraft carrier, nuclear-powered submarine, strategic bomber, F-22) to the Korean Peninsula. In recognition of the importance of the Combined Forces Command, since May 2013 the Park Geun-Hye Administration has been pushing ahead with re-postponement of Wartime Operational Control Transfer(which initially meant the disassembling of the CFC as of 1 December 2015) More recently, there has been a series of unusual indicators from the North. Judging from its inventory of 20 nuclear weapons, 1,000 ballistic missiles and biochemical weapons, it is safe to say that N. Korea has gained at least war deterrence against S. Korea. Normally a nation with nuclear weapons shrink its size of conventional forces, but the North is pursuing the opposite, rather increasing them. In addition, there was a change of war plan by N. Korea in 2010, changing 'Conquering the Korean Peninsula' to 'Negotiation after the seizure of the Greater Seoul Metropolitan Area(GSMA)' and establishing detailed plans for wartime projects. The change reflects the chain reaction in which requests from pro-north groups within the South will lead to the proclamation of war. Kim, Jeong-Un, leader of N. Korean regime, sent threatening messages using words such as 'exercising a nuclear preemptive strike right' and 'burning of Seoul'. Nam, Jae-June, Director of National Intelligence Service, stated that Kim, Jung-Un is throwing big talks, saying communization of the entire Korean Peninsula will come within the time frame of 3 years. Kim, Gwan-Jin, Defense Minister, shared an alarming message that there is a high possibility that the North will raise local provocations or a full-fledged war whenever while putting much emphasis on defense posture. As for the response concept of the Korean Government, it has been decided that 'ROK·US Combined Local Provocation Counter-Measure' will be adopted to act against local provocations from the North. Major provocation types include ▲ violation of the Northern Limit Line(NLL) with mobilization of military ships ▲ artillery provocations on Northwestern Islands ▲ low altitude airborne intrusion ▲ rear infiltration of SOF ▲ local conflicts within the Military Demarcation Line(MDL) ▲ attacking friendly ships by submarines. Counter-measures currently established by the US involves the support from USFK and USFJ. In order to keep the sworn promise, the US is reinforcing both USFK and USFJ. An all-out war situation will be met by 'CFC OPLAN5027' and 'Tailored Expansion Deterrence Forces' with the CFC playing a central role. The US augmentation forces stands at 690,000 troops, some 160 ships, 2,000 aircraft and this comprise 50% of US total forces, which is estimated to be ninefold of Korean forces. The CFC needs to be in center in handling both local provocations and an all-out war situation. However, the combat power of S. Korean conventional forces is approximately around 80% of that of N. Korea, which has been confirmed from comments made by Kim, Gwan-Jin, Defense Minister, during an interpellation session at the National Assembly. This means that S. Korean forces are not much growing. In particular, asymmetric capabilities of the North is posing a serious threat to the South including WMD, cyber warfare forces, SOF, forces targeting 5 Northwestern Islands, sub-surface and amphibious assault forces. The presence of such threats urgently requires immediate complementary efforts. For complementary efforts, the Korean Government should consider ① reinforcement of Korean forces; putting a stoppage to shrinking military, acquisition of adequate defense budget, building a missile defense and military leadership structure validity review, ② implementation of military tasks against the North; disciplinary measures on the sinking of ROKS Cheon-an/shelling of Yeonpyeong Islands, arrangement of inter-Korean military agreements, drawing lessons from studies on the correlation between aid for N. Korea, execution of inter-Korean Summit and provocations from the North, and ③ bolstering the ROK·US alliance; disregarding wartime operational control transfer plan(disassembling of CFC) and creation of a combined division.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1086-1091
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• 1999

$K^+-{\beta}/{\beta}"-Al_2O_3$ in the ternary system $K_2O-MgO-Al_2O_3$ was directly synthesized by solid state reaction. The phase formation and phase relation were carefully investigated in relation to starting composition, calcining temperature and time, and dispersion medium. The optimal synthetic condition was also examined for the formation of ${\beta}"-Al_2O_3$ phase with a maximum fraction. As a composition range, the mole ratio of $K_2O$ to $Al_2O_3$ was changed from 1:5 to 1:6.2 and the amount of MgO used as a stabilizer was varied from 4.2 wt % to 6.3 wt %. The calcining temperature was selected between $1000^{\circ}C$ and $1500^{\circ}C$. At $1000^{\circ}C$, the ${\beta}/{\beta}"-Al_2O_3$ phases began to form resulted from the combining of ${\alpha}-Al_2O_3$ and $KAlO_2$ and increased with temperature rising. All of ${\alpha}-Al_2O_3$ phase disappeared to be homogenized to the ${\beta}/{\beta}"-Al_2O_3$ phase at $1200^{\circ}C$. Near the temperature at $1300^{\circ}C$, the fraction of ${\beta}"-Al_2O_3$ phase showed a maximum value with the composition of $K_{1.67}Mg_{0.67}Al_{10.33}O_{17}$. At temperatures above $1300^{\circ}C$, the fraction of ${\beta}"-Al_2O_3$ phase decreased gradually owing to $K_2O$ loss caused by a high potassium vapor pressure, and the appropriate calcining time was about 5 hours. Acetone was more effective than distilled water as a dispersion medium for milling and mixing.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.152-160
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• 2009

Purpose : To intra-individually compare diagnostic accuracy of high-resolution contrast-enhanced magnetic resonance angiography (CE-MRA) with computed tomography angiography (CTA) and digital subtraction angiography (DSA) for the assessment of supraaortic steno-occlusive disease. Materials and Methods : Twenty-eight patients (20 men, 8 women, 53-79 years of age) underwent supraaortic CE-MRA, CTA and DSA. CE-MRA was performed on two 1.5T MR scanners (voxel dimension: $0.66{\times}0.66{\times}1.1$ or $1.2\;mm^3$), and CTA on 64-slice CT scanners (voxel dimension: $0.42{\times}0.42{\times}0.63\;mm^3$). All the three examinations were completed within 40 days (median 19 days; range 1-40 days). Retrospective evaluation and measurement of diameter of 6 extracranial and 9 intracranial arterial segments was done by 2 experienced radiologists. Results: A total of 420 arterial segments were examined by CE-MRA, CTA and DSA. On DSA, 34 stenoocclusive lesions were noted at extracranial (n= 19) and intracranial (n = 15) vessels. For extracranial stenosis greater than 70%, sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) were 94.7%, 98.7%, 90.0% and 99.3% on CE-MRA, and 94.7%, 99.3%, 94.7% and 99.3% on CTA. For intracranial stenosis greater than 50%, sensitivity; specificity, PPV and NPV were 93.3%, 98.3%, 77.8%and 99.6% on CE-MRA, and 86.7%, 97.9%, 72.2% and 99.1 % on CTA, with DSA as the standard of reference. Conclusion : Supraaortic CE-MRA is as reliable as CTA in depicting the arterial stenosis, and is effective in screening of significant stenosis of both extracranial and intracranial arterial stenosis.