• Geophysics and Geophysical Exploration
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• v.26 no.1
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• pp.18-30
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• 2023

Submarine mud volcanos are topographic features that resemble volcanoes, and are formed due to eruptions of fluidized or gasified sediment material. They have gained attention as a source of subsurface heat, sediment, or hydrocarbons supplied to the surface. In the continental slope of the Canadian Beaufort Sea, mud volcano exists at various water depths. The MV420, is an active mud volcano erupting at a water depth of 420 meters, and it has been the subject of extensive study. The Korea Polar Research Institute(KOPRI) collected high-resolution seismic data and heat flow data around the caldera of the mud volcano. By analyzing the multi-channel seismic data, we confirmed the reverse-polarity reflector assumed by a gas hydrate-related bottom simulating reflector(BSR). To further elucidate the relationship between the BSR and gas hydrates, as well as the thermal structure of the mud volcano, a numerical geothermal model was developed based on the steady-state heat equation. Using this model, we estimated the base of the gas hydrate stability zone and found that the BSR depth estimated by multi-channel seismic data and the bottom of the gas hydrate stability zone were in good agreement., This suggests the presence of gas hydrates, and it was determined that the depth of the gas hydrate was likely up to 50 m, depending on the distance from the mud conduit. Thus, this depth estimate slightly differs from previous studies.

• Journal of Life Science
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• v.20 no.2
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• pp.161-168
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• 2010

White-skinned sweet potato (Ipomoea batatas L.) has been traditionally used for diabetes treatment and management in many countries. In this experiment, methanol extract of white-skinned sweet potato (WSPMe) at a dose of 100 or 200 mg/kg body weight was tested to evaluate its effect on renal damage in streptozotocin (STZ)-induced diabetic rats. Its efficacy was compared with that of insulin secretogogue, glimepiride ($50\;{\mu}g/kg$ body weight). Experimental diabetes was induced by a single dose of STZ (45 mg/kg, i.p.) injection. The WSPMe and glimepiride were administered orally for 14 days and the effects on glucose, renal markers including blood urea nitrogen (BUN), creatinine and lactate dehydrogenase (LDH), lipid peroxide (LPO) level, antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathion-S-transferase (GST) activities in kidney were studied. An increase in BUN, creatinine, LDH, glucose, LPO levels and decrease in SOD, CAT, GPx and GST features were observed in diabetic control rats. Administration of WSPMe at a dose of 200 mg/kg body weight caused a significant improvement in blood glucose, LPO level, renal markers, lipid peroxidation markers and increased antioxidant levels in diabetic kidney. In conclusion, the WSPMe was found to be effective in reducing oxidative stress, thus confirming the ethnopharmacological use of I. batatas L. in protecting diabetes and its complications.

• Journal of Life Science
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• v.26 no.1
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• pp.129-139
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• 2016

Exercise increases the expression and interaction of major neurotrophic factors such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF) at both central and peripheral tissues, which contributes to improved brain and neural plasticity and cognitive function. Previous findings have been to understand the effect of light or moderate intensity aerobic exercise on neurotrophic factors and cognitive function, not that of high intensity aerobic exercise. However, recent findings suggest that high intensity interval training is a safe, less time-consuming, efficient way to improve cardiorespiratory fitness and weight control, thus American College of Sport Medicine (ACSM)’s guidelines for exercise prescription for various adult populations also recommend the application of high intensity interval training to promote their overall health. High intensity interval training also enhances the expression of BDNF, IGF-1, and VEGF at the brain and peripheral tissues, which improves cognitive function. Increased frequency of intermittent hypoxia and increased usage of lactate as a supplementary metabolic resource at the brain and neural components are considered a putative physiological mechanism by which high intensity interval training improves neurotrophic factors and cognitive function. Therefore, future studies are required to understand how increased hypoxia and lactate usage leads to the improvement of neurotrophic factors and what the related biological mechanisms are. In addition, by comparing with the iso-caloric moderate continuous exercise, the superiority of high intensity interval training on the expression of neurotrophic factors and cognitive function should be demonstrated by associated future studies.

• The Journal of Bigdata
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• v.5 no.2
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• pp.53-67
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• 2020

This study employees a supervised learning prediction model to detect nonconformity in advance of processed food manufacturing and processing businesses. The study was conducted according to the standard procedure of machine learning, such as definition of objective function, data preprocessing and feature engineering and model selection and evaluation. The dependent variable was set as the number of supervised inspection detections over the past five years from 2014 to 2018, and the objective function was to maximize the probability of detecting the nonconforming companies. The data was preprocessed by reflecting not only basic attributes such as revenues, operating duration, number of employees, but also the inspections track records and extraneous climate data. After applying the feature variable extraction method, the machine learning algorithm was applied to the data by deriving the company's risk, item risk, environmental risk, and past violation history as feature variables that affect the determination of nonconformity. The f1-score of the decision tree, one of ensemble models, was much higher than those of other models. Based on the results of this study, it is expected that the official food control for food safety management will be enhanced and geared into the data-evidence based management as well as scientific administrative system.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.675-695
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• 2023

The tracksite of dinosaurs and pterosaurs in Sanbuk-dong of Gunsan is the largest early Cretaceous dinosaur footprint fossil site in Korea, and all the footprints are important evidence indicating that large ornithopod and theropod dinosaurs inhabited the Korean peninsula during the early Cretaceous. The Sanbuk-dong site was covered with waterproof sheet in an outdoor environment until the installation of a protective enclosure in 2021. As a result, various factors such as shear force, load reduction, temperature and humidity fluctuations, acid rain, salinity and microorganisms have complexly interacted in the substrate of fossils, exacerbating the damage to footprints. For 159 footprints in 12 trackways among the footprints found in the site, the damage types were classified in detail and the level of each damage was assessed. The damages were classified into 6 types through the classification of deterioration degree of individual footprints. As a result of ultrasonic physical property evaluation on the surface of the fossil site, most of these footprints are in the completely weathered (CW) stage. Furthermore, various weathering patterns were observed in the study area, and surface contaminants were analyzed along the stratigraphy. Although the patterns of freshness and contaminants varied at different points within the fossil site, the chemical compositions were similar. Based on the results, an efficient conservation management system for dinosaur footprint fossils was established, and a conservation treatment type for each footprint was proposed.

• Journal of The Korean Association For Science Education
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• v.28 no.6
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• pp.649-663
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• 2008

The purpose of this study was to compare the processes of making hypotheses concerning the anomalous path of Wukong, a typhoon that came close to Korea recently, between an earth scientist and undergraduate students. Data were obtained through interviews with a practicing earth scientist as well as five undergraduate students. Inquiry reports of the students were also analysed. The result showed that while the earth scientist conducted a case study with already-established models of typhoon, the students were enabled to work on the specific case of Wukong only after they learned general theories on typhoons. Background knowledge played an important role for the scientist and students to formulate scientific hypotheses. Both the earth scientist and undergraduate students generate multiple working hypotheses, and they considered a couple of conditions to select more plausible hypotheses, including theoretical coherence, causative processes, and consistency with empirical data. Despite these similarities, there were differences in the scope and depth of background knowledge between the scientist and students. In addition, it was not likely that the undergraduate students possessed explicit perceptions of the conditions which could make a hypothesis more probable, except for the empirical consistency. Implications for science education and relevant research were discussed.

• The Korean Journal of Archival Studies
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• no.49
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• pp.213-246
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• 2016

On Kawara's works are not only artworks but are also his personal daily records. He produced many artworks whose theme centered on his everyday life, a plan that he had precisely made. He selected several specific themes from his daily life: when and where he met someone, what he read, and where he traveled. Kawara constantly recorded his daily life using various types of unconventional medium: maps, postcards, and telegrams. Although he was occupied with recording his everyday life, he was also active in forming public opinions on various issues through social media. Kawara's works, which exhibit a distinctive characteristic of himself, could be classified as individual records because it includes an individual's daily life and selected issues. His artworks express concern for or expose the irrationality of his society, which encourages ordinary people to let their voices be heard and take part in public affairs. Thus, his works function not just as art but also as precious historical records.

• Anatomy & Biological Anthropology
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• v.31 no.4
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• pp.105-119
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• 2018

Archaeogenetics is an academic discipline that aims to establish scientific facts of human history by integrating ancient DNA analyses with archaeological and anthropological evidence. After ancient DNA research was initiated about 30 years ago, it has been innovated so rapidly that the range of analysis has been extended toward the whole genome sequence of ancient genomes in recent 10 years. By this development, researchers have been able to study in detail the origins and migration patterns of hominin species and ancient human populations by approaches of evolutionary genetics. This study has reviewed main principles of the archaeogenetic analysis and the current trends of ancient genome studies with recent achievements. While sampling techniques and statistical analyses have been improved, typical research methods have been established by the findings on hominins and ancient western Eurasia populations. Recently, archaeogenecists have been applying the methods to studying those in other geographical areas. Nonetheless, there is still the lack of ancient genome research about populations in Eastern Asia including the Korean peninsula. This review ultimately aims to predict possibilities and promise of future ancient genome studies of ancient Korean populations.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.288-291
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• 2012

Korean oak wilt disease caused by Raffaelea quercus-mongolicae is vectored by the ambrosia beetle Platypus koryoensis. To prevent the spread of the disease, the beetle infested oak tree had been cut into logs, covered with plastic vinyl, fumigated with a pesticide, and stored for three years on the site where the tree was cut. This study was carried out to get information on the fungi colonizing the fumigated oak wood. Wood disk samples collected from the fumigated oak logs at two locations in the Taejo Mountain, Cheonan city, were used for fungal isolation. A total of 99 filamentous fungal isolates were obtained from the wood disk samples. Hypocrea spp., Trichoderma spp. and Penicillium spp. were identified based on morphological characteristics and nucleotide sequence analysis of translation elongation factor 1-alpha gene and ITS rDNA region. Trichoderma was the major fungal group. R. quercus-mongolicae, and P. koryoensis were not detected from the fumigated oak wood. Our work provided evidence that after three years of storage, the fumigated oak wilt-diseased logs should be no longer harmful source of oak wilt disease transmission.

• Journal of The Korean Association For Science Education
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• v.23 no.5
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• pp.470-483
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• 2003

This study analyzed the evolutionary content in 13 textbooks developed from the first to the 6th high school biology curriculum, The content analysis of textbooks, which were delineated nine component, was performed on the 80 evolutionary categories, According to the result, the proportion of the total evolutionary content in textbook increased from the textbooks developed by the Ist curriculum to the textbooks developed by the 6th curriculum, but the proportion of 'main narrative' in total evolutionary content was gradually decreased. It also showed that biology curriculum and points of view of textbook writers influenced on the proportion of evolutionary contents. On the whole, the topics of analysed textbooks exhibit insufficient diversity, Any categories- 'group selection', 'gene selection', 'gaps in fossil record', 'co-evolution', 'punctuated equilibrium', 'mosaic evolution', 'place of labor in human evolution', 'human race differentiation', 'criticism of "ontogeny recapitulates phylogeny", and 'human activities affecting evolution' - were not treated and others - 'theory of neutralism', 'theories of major episodes(excepting extinctions) found in the geologic time scale', 'sympatric speciation', 'clinal and area-effect speciation', 'polyploidy and evolution', 'gradualism' and 'evolution and origin of mammals' - were treated very lightly, the most emphasized topic was 'phylogeny in general' and 'formation of precells', 'miscellaneous' in the order of emphasis. 'Theory of natural selection' was lightly treated as just one of evolutionary theory though it should be emphasized as major theme of evolution. Also, the law of recapitulation, of which biologists doubt the validity, was discussed as an evidence of evolution in some textbooks. And the agents of genetic equilibrium disruption like genetic drift and migration were treated as of little importance. On the basis of above result, it was suggested that the textbook writers introduced the more meaningful evolutionary topics focused the theory of natural selection in explanation of evolution and evolution theory.