• Development and Reproduction
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• v.13 no.4
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• pp.291-296
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• 2009

In most larvae of ascidian, two sensory pigment cells, otolith and ocellus, lie in their brain vesicle. They also have a third type of sensory cells: hydrostatic pressure receptor (Hpr) cells. The Hpr cells were presumed to be hydrostatic pressure-detection cells, but their precise functions is still disputed. In this study, we investigated whether an FGF signaling is involved in formation of Hpr cells. When fertilized eggs were injected with Hr-FGF9/16/20 antisense MO, the resulting larvae showed severe abnormalities with no expression of the Hpr cell-specific Hpr-1 antigen. Similar results were obtained using an FGF receptor inhibitor, SU5402, and an MEK inhibitor, U0126. Embryos treated with SU5402 or U0126 during the 32-cell and hatching stages did not express the Hpr-1 antigen. To elucidate the temporal requirement for the FGF signaling in formation of Hpr cells, embryos were treated with SU5402 for 2 h, or U0126 for 20 min during various embryonic stages. Larvae treated with SU5402 from the 16-cell stage to the 64-cell stage did not express the Hpr-1 antigen, whereas those treated at the early gastrula stage expressed the Hpr-1 antigen. When U0126 treatment was carried out at various stages between the 8-cell and late gastrula stages, larvae scarcely formed the Hpr cells. They showed expression of the Hpr-1 antigen when embryos were placed in U0126 just before the neural plate stage. These results suggest that FGF9/16/20 signaling is involved in formation of Hpr cells from the primary neural induction stage to the late gastrula stage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.90-101
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• 2009

Analysis of multi-channel seismic reflection data from the Southern Ulleung Basin reveals that Plio-Quaternary section in the area consists of nine stacked sedimentary units separated by erosional unconformities. On the southern slope, these sedimentary units are acoustically characterized by chaotic seismic facies without distinct internal reflections, interpreted as debris-flow bodies. Toward the basin floor, the sedimentary units are defined by well-stratified facies with good continuity and strong amplitude, interpreted as turbidite/hemipelagic sediments. The seismic facies distribution suggests that deposition of Plio-Quaternary section in the area was controlled mainly by tectonic movement and sea-level fluctuations. During the Pliocene, sedimentation was mainly controlled by tectonic movements related to the back-arc closure of the East Sea. The back-arc closure that began in the Miocene caused compressional deformation along the southern margin of the Ulleung Basin, resulting in regional uplift which continued until the Pliocene. Large amounts of sediments, eroded from the uplifted crustal blocks, were supplied to the basin, depositing Unit 1 which consists of debris-flow deposits. During the Quaternary, sea-level fluctuations resulted in stacked sedimentary units (2-9) consisting of debris-flow deposits, formed during sea-level fall and lowstands, and thin hemipelagic/turbidite sediments, deposited during sea-level rise and highstands.

• The Korean Journal of Quaternary Research
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• v.24 no.2
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• pp.13-21
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• 2010

The Piseo-ri site in Muan provides significant data in investigation on the Paleolithic sites in the southwest coast of Korea. Stratigraphic and geological analysis indicates that the characteristic of soil wedge can vary in accordance with soil property and relief of paleo-surface. Considering that the cultural layer was deposited after the Last Glacial Maximum, co-occurrence of the late Middle to early Upper Paleolithic stone tools suggests a possibility of redeposition of different ages resulted from active erosion. The result shows that the distribution of the Paleolithic tools and the property of soil wedge could be controlled by environmental conditions such as relief of paleo-surface and climate.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.69-81
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• 2021

The exposed rocks in the Zacatecas state include mainly Mesozoic sedimentary and volcanic, Cenozoic volcanic and plutonic rocks. Paleozoic metamorphic rocks found in the northwestern portion of the state are considered as the most ancient rocks. These rocks correspond to the Caopas Formation which underlays the Later Paleozoic Rodeo Formation. The Mesozoic sequences are represented by a marine sedimentary sequence of the Later Triassic and the red beds of the Triassic-Jurassic Nazas Formation. The marine sediments of the Upper Jurassic overlay the Nazas Formation or metamorphic rocks from the Paleozoic. The Cretaceous sequences comprises marine sedimentary rocks in the north and northeast, and a volcanosedimentary set in the center and southeast. The Cenozoic is represented by volcanic nondifferentiated rocks, intrusive igneous rocks of acid and intermediate composition, and continental conglomerates with evaporitic sediments. The Quarternary sequences includes basalts, piedmont deposits, alluviums and occasionally, layers of evaporites and saltpeter. Furthermore, a great diversity of mineral deposits of both metallic and nonmetallic types occur in Zacatecas state. The rocks composing these deposits are extremely varied and include formations from Paleozoic to Tertiary. The mineralization age of ore deposits corresponds to the Tertiary in approximately 90%, and their genesis is mainly considered as epigenetic.

• Journal of the Korean earth science society
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• v.33 no.6
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• pp.534-543
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• 2012

The relationship between tectonic uplift and geophysical analysis of gravity anomalies and the in-situ stress fields in the Otway Ranges, SE Australia is addressed in this study to understand the nature and possible mechanism for the neotectonic movements. The uplift axis of the ranges is coincident with the regional Bouguer gravity highs whereas thick Tertiary sedimentary successions are highly correlated with the gravity lows along the basin rift geometry. This result suggests that the gravity highs are separated by the thick Tertiary sedimentary successions. Regional structural trends associated with faults and foldings of the deformed surfaces are consistent with the prevailing NW-SE $S_{Hmax}$ trend in this part of the continent. The anomalously positive correlation between topography and Bouguer gravity fields suggests possibly a lithospheric flexural deformation mode at a long wavelength (order of $10^2$ kms) in the region. It also suggests that the reactivation of pre-existing lithospheric structures driven by plate boundary forces plays a key role in this mode.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.395-400
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• 1983

The experiment was conducted to study the effect of protein level on weight gain, feed consumption and the efficiencies of feed, energy and protein when the broiler chick was fed the diet of different protein level with the iso-calorie content. The energy and protein level of the basal ration was 3200 kcal and 22.85% for starter period and 3265 Kcal and 18.58% for finisher period, respectively. In order to increase the protein level of the experimental diet, the basal diet was substituted by fish meal by the ratio of 3, 6, 9, and 12%. The male Abor Acre broiler chicks were employed for 8 weeks and the result obtained were as follows. 1. The weekly body weight gain was significantly greater for Diet C than for Diet A and E in the starter period and greater for Diet A than for Diet E in the finisher period (P<0.05). 2. In stater period the feed intake was not affected by the protein level but in finisher period the feed intake for Diet C, D, and E was significantly reduced compared with Diet A. 3. As for feed conversion ratio, Diet C of 1.43 was improved significantly compared with Diet A of 1.58(P<0.05). 4. As the protein level of diet increased, the energy efficiency ratio increased and however, the protein efficiency ratio decreased in starter and finisher period. In conclusion the best performance of broiler is thought to be realized when the protein and energy level was 23% and 3200 Kcal for starter period and 20% and 3250 Kcal for finisher period, respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.50-62
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• 1999

Sediment core samples recovered from the Korea Deep Ocean Study (KODOS)-97 area were divided into two or three units according to their distinct changes in sediment colors and chemical and physical properties. Analyses of radiolarian faunas in the sediments and $^{10}Be$ ratios in each unit were performed to reveal stratigraphic and paleoceanographic history of the study area. In the upper part of the sediments, Tertiary radiolarians were mixed at various proportions with Quaternary assemblages probably by reworking process of bottom current and benthic animals. Dissolution of radiolarians was severe in deeper depth and in the Unit III, only few of the fragments of corroded Tertiary radiolarians were detectable. The mid layer of the Unit I belonged to Collosphaera invaginata Zone, the time period of 0.21 Ma. The Unit II belonged to Collosphaera tuberosa Zone with the time period younger than 0.42 Ma which was observed above the Stylatractus universus Zone. The Unit III is assigned to Tertiary, which is younger than the Late Eocene. Composition analyses of radiolarian assemblage and $^{10}Be$ ratio data indicated hiatus periods of more than 3 My between late of Middle Miocene and Pliocene resulting from erosion and dissolution caused by Antarctic Bottom Water. Stratigraphic evidence from radiolaria was well correlated with $^{10}Be$ data. Sedimentation rate during Quaternary can be suggested as 0.15-0.5 mm per 1000 years. Dominance of warm-water radiolaria species and the results reflected minimum climatic changes of tropical conditions.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.437-457
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• 2004

The geology of the Kualakulun in the Middle Kalimantan, Indonesia comprises Permian to Carboniferous Pinoh Metamorphic Rocks and Cretaceous Sepauk Plutonics of the Sunda Shield, late Eocene Tanjung Formation, Oligocene Malasan Volcanics, Oligocene to early Miocene Sintang Intrusives and Quaternary alluvium. Tanjung Formation was deposited in low-and high-sinuosity channel networks developed on the proximal to distal delta plain and delta front forming southward paleoflow system, which, in turn, gradually change into shallow marine environment. Four main deformational phases are recognized: D1, folding of metamorphic rocks accompanied by development of S1 schistosity under regional metamorphic condition; D2, ductile shearing in Cretaceous granitoids; D3, folding of metamorphic rocks accompanied by S2 crenulation cleavage; D4, faulting under N-S compressional regime during Tertiary times, producing NE-trending sinistral and NW-trending dextral strike-slip faults and N-S to NNE-trending normal faults.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.335-346
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• 2005

In this study, core sediments and pore water were analysed to identify the origin of organic matter and Bas in late Quaternary sediments from the northwestern Ulleung Basin of the East Sea. C/N and C/S ratios in the sediments show that the organic matter in the study area originated predominantly from marine algae. However, the results of Rock-Eval pyrolysis indicate that the organic matter has an origin of the land-plant (Type III), locating in the immature stage. These different results might be due to the heavy oxidizing of the organic matter during sinking down to the seafloor or after deposition in the sediments. Concentration of sulfate in the pore water decreases gradually with core depth, while concentration of $CH_4$ increases gradually with core depth. This indicates that sulfate reduction and methanogenesis occurred actively in the sediments. Also, it is likely that the compositions of $CH_4$ are characterized as a more biogenic origin, mostly caused by microbial activity, rather than a thermogenic one.

• The Journal of the Petrological Society of Korea
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• v.28 no.4
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• pp.347-357
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• 2019

The main fault zone of the Yangsan Fault, located in the southeastern part of the Korean peninsula, is newly found at the Cheonjin-ri, Dudong-myeon, Ulju-gun, Ulsan, Korea. About 100 wide fault zone exposed along the Guryangcheon stream strikes N-S and dips over 70° toward east. The main fault zone is composed of N-S-striking gouge and breccia layers and enclosed lenses. Striations on the subvertical fault surfaces mainly indicate dextral slip, but moderate-angle minor reverse faults showing top-tothe-west shearing transect the foliated high-angle gouge and breccia layers. These indicate that the dextral slip along the fault, which is interpreted as the main movement of the fault, was followed by reverse slip. The fault zone is composed of N-S-striking gouge layers and enclosed, fractured lenses. Locally distributed NE-SW- to E-W-striking fault gouge layers with fractured lenses show asymmetric folds, indicating progressive dextral movement. Therefore, the exposed fault zone has a high internal complexity due to the combined effects of NNE-SSW-trending dextral shearing and E-W-trending shortening by compression. In addition, around main boundary fault between the western volcanic rocks and eastern sedimentary rocks offsets the overlying Quaternary fluvial conglomerate. This is a good example that understanding of internal structures of main fault zone (or fault core), such as the Yangsan Fault, plays an important role to study the Quaternary activity and to find the active fault.