• 자원환경지질
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• 제55권6호
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• pp.597-616
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• 2022

The Chungnam basin is a crucial area for studying the Mesozoic crustal evolutionary history of the Korean Peninsula. This study reports the revised geology and new isotopic ages from the northeastern Chungnam Basin based on detailed geological mapping and LA-ICP-MS zircon U-Pb analysis. Our renewed geologic map defines intra-basin, basin-bounding, and basement fault systems closely related to hydrothermal gold-bearing quartz vein injections. Here, we propose the directions of (micro)structural and geochronological future work to address issues on the relationship between the tectonic process, basin evolution, and hydrothermal fluid migration in the southwestern Korean Peninsula.

• Genomics & Informatics
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• 제21권2호
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• pp.27.1-27.7
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• 2023

Recombination events complicate the evolutionary history of populations and species and have a significant impact on the inference of isolation-with-migration (IM) models. However, several existing methods have been developed, assuming no recombination within a locus and free recombination between loci. In this study, we investigated the effect of recombination on the estimation of IM models using genomic data. We conducted a simulation study to evaluate the consistency of the parameter estimators with up to 1,000 loci and analyze true gene trees to examine the sources of errors in estimating the IM model parameters. The results showed that the presence of recombination led to biased estimates of the IM model parameters, with population sizes being more overestimated and migration rates being more underestimated as the number of loci increased. The magnitude of the biases tended to increase with the recombination rates when using 100 or more loci. On the other hand, the estimation of splitting times remained consistent as the number of loci increased. In the absence of recombination, the estimators of the IM model parameters remained consistent.

• 천문학회보
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• 제45권1호
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• pp.66.2-66.2
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• 2020

We propose a deep learning analysis technique with a convolutional neural network (CNN) to predict the evolutionary track of the Epoch of Reionization (EoR) from the 21-cm differential brightness temperature tomography images. We use 21cmFAST, a fast semi-numerical cosmological 21-cm signal simulator, to produce mock 21-cm maps between z = 6 ~ 13. We then apply two observational effects, such as instrumental noise and limit of (spatial and depth) resolution somewhat suitable for realistic choices of the Square Kilometre Array (SKA), into the 21-cm maps. We design our deep learning model with CNN to predict the sliced-averaged neutral hydrogen fraction from the given 21-cm map. The estimated neutral fraction from our CNN model has great agreement with the true value even after coarsely smoothing with broad beam size and frequency bandwidth and heavily covered by noise with narrow beam size and frequency bandwidth. Our results show that the deep learning analyzing method has the potential to reconstruct the EoR history efficiently from the 21-cm tomography surveys in future.

• 한국정보과학회논문지:데이타베이스
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• 제33권3호
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• pp.251-260
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• 2006

단백질 일차 구조(아미노산 배열)에 대한 상동 검색은 유전자나 단백질의 기능과 진화 과정을 유추하기 위한 필수 연산이다. 그러나 진화 단계가 멀리 떨어진 경우 단백질 일차 구조는 보존되지 않기 때문에 단백질의 공간적 구조에 대한 유사 검색을 통해서만 진화 단계를 유추할 수 있다. 따라서 본 논문에서는 단백질의 공간적 구조를 표현하는 단백질 이차 구조를 대상으로 하여 RDBMS상에 쉽게 구현이 가능한 인덱싱 방안을 제안한다. 제안된 인덱싱 방안은 클러스터링 기법과 LookAhead 개념을 활용하여 Exact Match, Range Match, Wildcard Match 질의를 신속하게 처리한다. 제안된 방법의 우수성을 검증하기 위하여 실제의 단백질 데이타를 대상으로 성능 평가를 수행하였다. 실험 결과에 의하면, 제안된 방법은 기존의 방법과 비교하여 Exact Match의 경우 6.3배까지, Range Match의 경우 3.3배까지, Wildcard Match의 경우 1.5배까지의 개선된 검색 성능을 가지는 것으로 나타났다.

• ALGAE
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• 제26권1호
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• pp.21-32
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• 2011

Studies of the red algal genus Bostrychia over the last 15 years have made it a model system for many evolutionary processes within red algal species. The combination of newly developed, or first employed methods, in red algal species studies has made Bostrychia a pioneer genus in intraspecific studies. Bostrychia was the first genus in which a mitochondrial marker was used for intraspecific red algal phylogeny, and the first for which a 3-genome phylogeny was undertaken. The genus was the first red alga used to genetically show maternal plastid and mitochondria inheritance, and also to show correlation between cryptic species (genetically divergent intraspecific lineages) and reproductive incompatibility. The chemotaxonomic use, and physiological function of osmolytes, has also been extensively studied in Bostrychia. Our continuous studies of Bostrychia also highlight important aspects in algal species studies. Our worldwide sampling, and resampling in certain areas, show that intensive sampling is needed to accurately assess the genetic diversity and therefore phylogeographic history of algal species, with increased sampling altering evolutionary hypotheses. Our studies have also shown that long-term morphological character stability (stasis) and character convergence can only be correctly assessed with wide geographic sampling of morphological species. While reproductive incompatibility of divergent lineages supports the biological species nature of these lineages, reproductive incompatibility is also seen between isolates with little genetic divergence. It seems that reproductive incompatibility may evolve quickly in red algae and the unique early stages of fertilization (e.g., gametes covered by walls, active movement of spermatium nuclei to the distant egg nucleus), also well investigated in Bostrychia,. may be key to our understanding of this process.

• ALGAE
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• 제17권1호
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• pp.53-58
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• 2002

The transition of plant life from aquatic algae to land to land plants was one of the major events in the history of life. However, in hypothesizing the exact evolutionary path of the transition, limited shared phenotypic characters in aquatic algae and land plants (embryophytes) have been a major hinderance. Chloroplast genomes contain characters useful in tracing evolutionary histories. Embryophyte chloroplast genomes are distinguished from algal cpDNAs by having over 20 group Ⅱ introns, some of which were gained during the transition from algae to embryophytes (Manhart and Palmer 1990; Lew and Manhart 1993;Lee and Manhart 2002). Here we examine a gene cluster that, in land plants, contains psbB, psbT, psbH, petB and petD with introns found in petB and petD (petB.i and petD.i). In addition the presence/absence of introns in trnA and trnI (trnA.i and trnI.i) were determined in all five major lineages of charophytes. We found that the psbB gene cluster occurs in most surveyed charophytes and embryophytes except Spirogyra (Zygnematales) which lacks it due to intra-genomic rearrangement. All four introns are absent in Chlorokybus but present in some or all of the other four charophyte lineages (Klebsormidiales, Zygnematales, Coleochaetales, and Charales). In addition, Chlorokybus is distinguished from other charophytes and embryophytes by having an unusually long spacer (over 2 kb) between psbH-petB. The results indicate that Chlorokybus diverged before the intron gains but after psbB gene cluster formation, placing the other charophyte lineages closer to embryophytes.

• 한국과학교육학회지
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• 제37권4호
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• pp.659-668
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• 2017

이 연구는 진화 개념의 발달 단계가 전공과 국가에 따라서 유의미한 차이가 있는지 확인하기 위하여 진행되었다. 이 연구를 위하여 한국과 미국의 대학생의 자료를 생물 전공과 비생물 전공에 따라 구분하여 수집하였다. Ha(2007)이 개발한 도구를 사용하여 Ha(2016)의 분석방법에 근거하여 순위선다형으로 분석하였다. 연구 결과 진화적 사고의 과학사적 발달 과정(창조, 목적, 의도, 용불용설, 자연선택)을 토대로 순위선다방식으로 분석하는 방법이 한국과 미국, 전공과 비전공 학생에게도 적합하게 적용될 수 있는 방법임이 확인되었다. 진화 개념의 발달 단계를 확인한 결과 우리나라 대학생들은 용불용설 수준, 미국의 대학생들은 목적론적 설명 수준에 있는 것으로 확인되었다. 전공과 국가에 따른 진화 개념의 발달 수준은 진화 설명소재와 교호작용효과가 있는지 확인한 결과 유의미한 교호작용효과가 없는 것으로 확인되었다. 진화 개념의 발달 단계와 종교성은 유의미한 관련성이 있었다. 이 연구 결과들을 토대로 진화 개념의 발달 특성에 대해서 논의한다.

• ALGAE
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• 제34권2호
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• pp.153-162
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• 2019

Anthropogenic disturbances, including coastal habitat modification and climate change are threatening the stability of kelp beds, one of the most diverse and productive marine ecosystems. To test the effect of temperature and irradiance on the microscopic gametophyte and juvenile sporophyte stages of the rare kelp, Saccharina angustissima, from Casco Bay, Maine, USA, we carried out two sets of experiments using a temperature gradient table. The first set of experiments combined temperatures between $7-18^{\circ}C$ with irradiance at 20, 40, and $80{\mu}mol\;photons\;m^{-2}\;s^{-1}$. The second set combined temperatures of $3-13^{\circ}C$ with irradiance of 10, 100, and $200{\mu}mol\;photons\;m^{-2}\;s^{-1}$. Over two separate 4-week trials, in 2014 and again in 2015, we monitored gametogenesis, the early growth stages of the gametophytes, and early sporophyte development of this kelp. Gametophytes grew best at temperatures of $8-13^{\circ}C$ at the lowest irradiance of $10-{\mu}mol\;photons\;m^{-2}\;s^{-1}$. Light had a significant effect on both male and female gametophyte growth only at the higher temperatures. Temperatures of $8-15^{\circ}C$ and irradiance levels of $10-100{\mu}mol\;photons\;m^{-2}\;s^{-1}$ were conditions for the highest sporophyte growth. Sporophyte and male gametophyte growth was reduced at both temperature extremes-the hottest and coldest temperatures tested. S. angustissima is a unique kelp species known only from a very narrow geographic region along the coast of Maine, USA. The coupling of global warming with high light intensity effects might pose stress on the early life-history stages of this kelp, although, as an intertidal species, it could also be better adapted to temperature and light extremes than its subtidal counterpart, Saccharina latissima.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.248-261
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• 2021

Attributable to their major function in pathogen recognition, the use of bovine leukocyte antigens (BoLA) as disease markers in immunological traits in cattle is well established. However, limited report exists on polymorphism of the BoLA gene in zebu cattle breeds by high resolution typing methods. Thus, we used a polymerase chain reaction sequence-based typing (PCR-SBT) method to sequence exon 2 of the BoLA class II DRB3 gene from 100 animals (Boran, n = 13; Sheko, n = 20; Fogera, n = 16; Horro, n = 19), Hanwoo cattle (n = 18) and Bangladesh Red Chittagong zebu (n = 14). Out of the 59 detected alleles, 43 were already deposited under the Immuno Polymorphism Database for major histocompatibility complex (IPD-MHC) while 16 were unique to this study. Assessment of the level of genetic variability at the population and sequence levels with genetic distance in the breeds considered in this study showed that Zebu breeds had a gene diversity score greater than 0.752, nucleotide diversity score greater than 0.152, and mean number of pairwise differences higher than 14, being very comparable to those investigated for other cattle breeds. Regarding neutrality tests analyzed, we investigated that all the breeds except Hanwoo had an excess number of alleles and could be expected from a recent population expansion or genetic hitchhiking. Howbeit, the observed heterozygosity was not significantly (p < 0.05) higher than the expected heterozygosity. The Hardy Weinberg equilibrium (HWE) analysis revealed non-significant excess of heterozygote animals, indicative of plausible over-dominant selection. The pairwise FST values suggested a low genetic variation among all the breeds (FST = 0.056; p < 0.05), besides the rooting from the evolutionary or domestication history of the cattle. No detached clade was observed in the evolutionary divergence study of the BoLA-DRB3 gene, inferred from the phylogenetic tree based on the maximum likelihood model. The investigation herein indicated the clear differences in BoLA-DRB3 gene variability between African and Asian cattle breeds.

• 지구물리와물리탐사
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• 제20권3호
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• pp.146-162
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• 2017

동해 울릉분지 북서해역에 위치한 해저협곡의 층서 및 발달사를 연구하기 위해 다중빔 및 탄성파 자료를 분석하였다. 탄성파 자료 해석에 의하면 연구지역의 퇴적층은 침식 부정합면에 의해 분리되는 4개의 층서단위로 구분된다. 대륙사면에 발달한 퇴적층은 사면붕락을 포함하는 평행층리 음향상이 우세한 반면, 분지로 향하면서 평행층리 음향상과 캐오틱 음향상을 보이는 퇴적층이 분포한다. 전반적으로 사면에서는 얇은 층후를 보이며, 사면기저부와 분지 평원에서는 두꺼운 층후로 발달한다. 탄성파 특징과 분포에 의하면 각 층서단위의 퇴적은 해저협곡의 발달사와 잘 대비된다. 음향기반 암 상부에 위치하는 층서단위 1은 사면에서는 얇은 층후로 발달하며 분지로 향하면서 층후는 점차 증가한다. 층서단위 2는 다른 층서단위에 비해 사면에서 두꺼운 층후를 보이며 단층과 관련된 사면붕락이 발생한다. 사면붕락에 의해 유발된 질량류 퇴적체는 사면기저부에 주로 퇴적되며, 이 퇴적체는 심해 선상지로 해석된다. 퇴적물의 퇴적보다는 침식작용이 우세하여 협곡의 폭과 깊이는 증가한다. 층서단위 3은 해저협곡 주변부의 사면에서 얇은 층후를 보이며, 분지로 향하면서 퇴적두께는 점차 증가한다. 층서단위 4는 사면에서 슬라이드/슬럼프를 포함하는 얇은 층후를 보이며, 사면기저부에는 두꺼운 층후로 퇴적되는 심해 선상지가 발달한다. 해저협곡 주변부에서의 사면붕락과 우세한 침식작용에 의해 해저협곡의 폭과 깊이는 증가한다. 결과적으로 연구지역의 해저협곡과 연계된 층서단위의 형성은 사면붕락에 의한 퇴적물 공급량, 광역적인 구조운동, 해수면 변동에 의해 크게 조절되었다.