• 천문학회보
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• 제38권2호
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• pp.62.2-62.2
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• 2013

Recent spectroscopic observations have provided evidence for complex chemical evolution by supernovae and/or asymptotic giant branch (AGB) stars in the two metal-poor globular clusters (GCs) NGC2419 and M15. In particular, the horizontal branches (HBs) of these metal-poor GCs are very extended in the Hertzsprung-Russell diagram. The origin of these peculiar features, as well as that for the Sandage period-shift effect observed in these clusters, are yet to be understood. Here we show, by constructing population models including the Nitrogen enhanced subpopulation, that the second generation populations in these clusters would be enhanced not only in Helium, but also in Nitrogen. This working hypothesis can simultaneously explain the observed extended feature on the HB and the period-shift of RR Lyrae variables.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1992년도 한국우주과학회보 제2권1호
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• pp.15-15
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• 1993

During the past two decades, ultraviolet(UV) observations of elliptical galaxies and spiral bulges from the OAO-2 and HE satellites have established that the upturn in the specturm below 2000A is a common feature of these early-type system Because of its important implications for the formation of galaxies, astuonemical literature is replete with nurmerous discussions about the origin of the UV flux yet the situation remains controversal. New light on the problem is shed by the recent observations Some the Astro-1 space shuttle mission which suggest that the metal-poor horizontal-branch(HB) stars merit more detailed consideration for the origin of the UV flux It is shown here that such stars in these systems can indeedexplain the UV flux It is suggested that ttle obserred correlation between the UVupturn and total mass is due to the Possibility that the more massive galaxies tend to form earlier than the less massive galaxies as a result of mere efficient star formation in denser environments. It remains a task of mere detailed population synthesis nudels, now in progress, to put these results on a firmer quantitative basis.

• 농촌계획
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• 제23권2호
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• pp.43-54
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• 2017

When an age of low growth and population decline, population migration plays an important role in spatial structure of region. There have been many researches on migration and regional spatial structure. The purpose of this study is to examine the changes of Gwangju and Jeonnam region's spatial structure and central area using social network analysis methods. For analysis it was used that population and migration data and passenger OD(Origin and Destination) travel data released by Statistics Korea and Korea Transport Database(KTDB). Using Gephi 0.8.2, migration and passenger OD networks were visualized, and this describe network flow and density. The results of the network centrality analysis show that the most populated village is not always network center though population mass is an important factor of central places. The average eigenvector centrality of 2010 migration is the lowest during 2005-2015, and it means few regions have high centralities. When comparing migration and travel networks, travel data is more effective than migration data in determining the central location considering spatial functions.

• 한국어류학회지
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• 제23권2호
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• pp.95-105
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• 2011

이 연구는 cytochrome b 유전자 서열을 이용하여 쏘가리속 어류의 분자계통 진화적 관계와 쏘가리 지역 개체군 간의 유전적 차이를 조사함으로써 한극산 쏘가리의 분자진화적인 위치와 유래를 알기 위하여 실시하였다. 그 결과, 쏘가리속 어류의 진화초기에 S. roulei가 가장 먼저 분화하였으며 그 후 조사대상 어류인 쏘가리속 6개 종 (S. schezeri, S. undu-lata, S. fortis, S. obscura, S. knerii 및 S. chuatsi) 이 분화한 것으로 생각된다. 그러나 이들 어류들의 분화 우선순위는 통계학적으로 강하게 지지되지 못해서 명확하게 밝히기는 어려웠다. 한편 쏘가리 개체군은 크게 세 개의 집단으로 구분되었다. 첫 번째 집단은 한국산 개체군과 중국북부 (Liaoning, Henan) 개체군이다. 두 번째 집단은 Anhui, Fujian 및 Guangxi 개체군이며, 세 번째 집단은 Zhejiang 개체군이다. 첫 번째 집단 내 한국산 쏘가리 개체군과 중국 북부(Liaoning, Henan)개체군 사이의 염기서열 차이는 1~5 base pairs (bp)였으며 첫 번째 집단과 두 번째 집단의 염기서열 차이는 31~43 bp였다. 그리고 두 번째 집단과 세 번째 집단 사이의 염기서열 차이는 37~44 bp를 나타냈으며, 첫 번째 집단과 세 번째 집단 사이의 염기서열 차이는 27~29 bp였다. 따라서 한국산 쏘가리의 유래는 중국의 북부 개체군이 신생대 3기 Pliocene 기간 중에, 즉 초기 빙하기 이전 시기에 중국 중부 또는 남부의 쏘가리 개체군으로부터 최초로 분화된 후 빙하기를 거치면서 한반도로 그 분포범위를 확장함으로써 생겨난 것으로 추정된다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권9호
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• pp.1369-1377
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• 2020

Objective: The main objectives of the present study were to assess the genetic diversity, population structure and to appraise the efficiency of ongoing selective breeding program in the closed nucleus herd of Nellore sheep through pedigree analysis. Methods: Information utilized in the study was collected from the pedigree records of Livestock Research Station, Palamaner during the period from 1989 to 2016. Genealogical parameters like generation interval, pedigree completeness, inbreeding level, average relatedness among the animals and genetic conservation index were estimated based on gene origin probabilities. Lambs born during 2012 and 2016 were considered as reference population. Two animal models either with the use of F_i or ΔF_i as linear co-variables were evaluated to know the effects of inbreeding on the growth traits of Nellore sheep. Results: Average generation interval and realized effective population size for the reference cohort were estimated as 3.38±0.10 and 91.56±1.58, respectively and the average inbreeding coefficient for reference population was 3.32%. Similarly, the effective number of founders, ancestors and founder genome equivalent of the reference population were observed as 47, 37, and 22.48, respectively. Fifty per cent of the genetic variability was explained by 14 influential ancestors in the reference cohort. The ratio f_e/f_a obtained in the study was 1.21, which is an indicator of bottlenecks in the population. The number of equivalent generations obtained in the study was 4.23 and this estimate suggested the fair depth of the pedigree. Conclusion: Study suggested that the population had decent levels of genetic diversity and a non-significant influence of inbreeding coefficient on growth traits of Nellore lambs. However, small portion of genetic diversity was lost due to a disproportionate contribution of founders and bottlenecks. Hence, breeding strategies which improve the genetic gain, widens the selection process and with optimum levels of inbreeding are recommended for the herd.

• Fisheries and Aquatic Sciences
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• 제22권6호
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• pp.12.1-12.8
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• 2019

Background: Wild fish populations stock is continuously diminishing in the Indo-Ganges river basin, and the population status of most fishes is unidentified. The identification of the population status and the conservation of commercially important and endemic wild fish populations in this region are crucial for the management. The aim of this paper was to identify the population status of Cirrhinus reba, a promising aquaculture but vulnerable species in the Indo-Ganges river basin in Bangladesh. Methods: C. reba samples were collected from four isolated populations of the Brahmaputra (n = 30), the Padma (33), the Karatoya (31), and the Jamuna Rivers (30) in Bangladesh, and the population status was evaluated using morphometric and landmark comparisons. Data were analyzed with the Kruskal-Wallis test, univariate analysis, discriminant function analysis, and the formation of a dendrogram. Results: Three meristic characters (Pectoral fin rays, caudal fin rays, scale in lateral lines), four morphometric characters (head length, pre-orbital length, post-orbital length, maximum body depth), and truss measurement (4-7) were significantly different among the stocks. The step-wise discriminant function analysis retained 15 variables from morphometric and landmark measurements that significantly differentiated the populations based on the constructed DFI and DFII. Discriminate function analysis also showed that 91.2% of the original groups were classified into their correct samples. The cluster analysis of Euclidean distances placed the Jamuna population in one cluster and the Brahmaputra, the Padma, and the Karatoya populations in the second one. Conclusion : Morphological differences among the stock were probably due to different ancestral origin. This is the first report about population status of C. reba in their natural habitat of the Indian subcontinent. Further genetic studies and the evaluation of environmental impact on C. reba populations in Bangladesh are suggested to support our findings.

• Asian-Australasian Journal of Animal Sciences
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• 제33권6호
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• pp.902-912
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• 2020

Objective: Mongolia is one of a few countries that supports over 25 million goats, but genetic diversity, demographic history, and the origin of goat populations in Mongolia have not been well studied. This study was conducted to assess the genetic diversity, phylogenetic status and population structure of Mongolian native goats, as well as to discuss their origin together with other foreign breeds from different countries using hypervariable region 1 (HV1) in mtDNA. Methods: In this study, we examined the genetic diversity and phylogenetic status of Mongolian native goat populations using a 452 base-pair long fragment of HVI of mitochondrial DNA from 174 individuals representing 12 populations. In addition, 329 previously published reference sequences from different regions were included in our phylogenetic analyses. Results: Investigated native Mongolian goats displayed relatively high genetic diversities. After sequencing, we found a total of 109 polymorphic sites that defined 137 haplotypes among investigated populations. Of these, haplotype and nucleotide diversities of Mongolian goats were calculated as 0.997±0.001 and 0.0283±0.002, respectively. These haplotypes clearly clustered into four haplogroups (A, B, C, and D), with the predominance of haplogroup A (90.8%). Estimates of pairwise differences (Fst) and the analysis of molecular variance values among goat populations in Mongolia showed low genetic differentiation and weak geographical structure. In addition, Kazakh, Chinese (from Huanghuai and Leizhou), and Arabian (Turkish and Baladi breeds) goats had smaller genetic differentiation compared to Mongolian goats. Conclusion: In summary, we report novel information regarding genetic diversity, population structure, and origin of Mongolian goats. The findings obtained from this study reveal that abundant haplogroups (A to D) occur in goat populations in Mongolia, with high levels of haplotype and nucleotide diversity.

• 한국어류학회지
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• 제35권4호
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• pp.217-223
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• 2023

잔가시고기 Pungitius kaibarae의 신규 집단인 고령(GR) 집단과 야생 집단의 특성을 규명하기 위해 미토콘드리아 cytb 유전자 영역의 886 bp 서열을 이용 총 4개 집단 (경상북도 고령(회천, GR), 포항(곡강천, PH), 경산(오목천, GYSA), 강원도 고성(배봉천, GS))을 분석하였다. 고령(GR) 집단에서 가장 낮은 haplotype 다양성을 나타냈고(H_d=0.000), 고성(GS) 집단에서 0.755로 가장 높은 haplotype 다양성을 확인하였다. Nucleotide 다양성은 고성(GS) 집단에서 0.00291로 가장 높은 다양성을 나타냈으며, 고령(GR) 집단에서 가장 0.00000로 가장 낮은 다양성을 보였다. 유전적 분화도에서 고령(GR) 집단은 포항(PH) 집단과 유전적으로 가장 가까운 것으로 나타났다. Haplotype 네트워크는 고령 (GR) 집단이 포항(PH) 집단과 군집되어 가장 유사한 것으로 나타났다. 고령(GR) 집단은 계통발생학적 tree에서 높은 지지도(98%)의 값으로 포항(PH) 집단과 군집됨을 확인하였다. 따라서 고령(GR) 집단은 포항(PH) 집단과 유사한 집단에서 유래됨을 추정하였다.

• Journal of Chest Surgery
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• 제4권2호
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• pp.81-86
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• 1971

Aneurysm of the Aorta is a grave disease mostly producing disabling symptoms and ultimate death by rupture and hemorrhage without surgical intervention. Aneurysm of the thoracic aorta is more common in arteriosclerosis than syphilitic origin,since the incidence of cardiovascular syphilis has been reduced significantly in recent decades and the life span of population has increase. We have experienced a case of luetic aneurysm of aortic arch without pulse in tile left arm which was succesfully treated by surgical intervention.

• Journal of Plant Biotechnology
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• 제2권2호
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• pp.101-108
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• 2000

The liverwort Pellia borealis is a diploid, monoecious, allopolypliod species (n=18) that as it was postulated, originated after hybridization and duplication of chromosome sets of two cryptic species: Pellia epiphylta-species N (n=9) and Pellia epiphylla-species 5 (n=9). Our recent results have supported the allopolyploid origin of P.borealis. We have shown that the nuclear genome of P.borealis consists of two nuclear genomes: one derived from P.epiphylla-species N and the other from P.epiphylla-species 5. In this paper we show the origin of chloroplast and mitochondrial genomes in an allopolyploid species P.borealis. To our knowledge there is no information concerning the way of mitochondria and chloroplast inheritance in Brophyta. Using an allopolyploid species of p. borealis as a model species we have decided to look into chloroplast and mitochondrial genomes of P.borealis, P.epiphylla-species N and P.epiphylla-species S for nucleotide sequences that would allow us to differentiate between both cryptic species and to identify the origin of organelle genomes in the alloploid species. We have amplified and sequenced a chloroplast $tRNA^{Leu}$ gene (anticodon UAA) containing an intron that has shown to be highly variable in a nucleotide sequence and used for plant population genetics. Unfortunately these sequences were identical in all three liverwort species tested. The analysis of the nucleotide sequence of chloroplast, an intron containing $tRNA^{Gly}$ (anticodon UCC) genes, gave expected results: the intron nucleotide sequence was identical in the case of both P.borealis and P.epiphyllaspecies N, while the sequence obtained from P.epiphyllasperies S was different in several nucleotide positions. These results were confirmed by the nucleotide sequence of another chloroplast molecular marker the chloroplast, an intron-contaning $tRNA^{Lys}$ gene (anticodon UUU). We have also sequenced mitochondrial, an intron-containing $tRNA^{Ser}$ gene (anticodon GCU) in all three liverwort species. In this case we found that, as in the case of the chloroplast genome, P.borealis mitochondrial genome was inherited from P.epiphylla-species N. On the basis of our results we claim that both organelle genomes of P.borealis derived from P.epiphylla-species N.