• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.75-85
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• 2019

The purpose of this study is to understand the vegetation characteristics of ridges (Gyeongsusan-Seonunsan-Gaeipalsan) in the Seonunsan Provincial Park and to establish reference information for the management of the park in the future. We designated 62 plots with the area of $100m^2$ were installed and analyzed them to investigate the vegetation characteristics. The results of community classification based on TWINSPAN showed seven categories of vegetation communities in the surveyed region: Quercus dentata-Deciduous broad-leaved Community, Quercus variabilis-Pinus thunbergii-Quercus serrata Community, Pinus densiflora Community, Deciduous broad-leaved Community-I, Carpinus tschonoskii-Castanea crenata-Quercus aliena Community, Deciduous broad-leaved Community-II, and Carpinus tschonoskii-Carpinus laxiflora Community. In the vegetation of Seonunsan Provincial Park, coniferous trees such as Pinus thunbergii and Pinus densiflora have been gradually losing their population as part of ecological succession to deciduous broad-leaved trees such as Quercus spp., Carpinus tschonoskii, and Carpinus laxiflora. Moreover, Carpinus turczaninowii, Mallotus japonicus, and others were identified as vegetation reflecting the geographical characteristics of the region neighboring the west coast. The estimated age is 30-60 years, and the oldest tree Pinus densiflora is 63-years old. The index of diversity ($100m^2$) was 0.7942 for Carpinus tschonoskii-Carpinus laxiflora Community, 0.8406 for Carpinus tschonoskii-Castanea crenata-Quercus aliena Community, 0.8543 for Quercus dentata-Deciduous broad-leaved Community, 0.9434 for Quercus variabilis-Pinus thunbergii-Quercus serrata Community, 0.9520 for Deciduous broad-leaved Community-I, 0.9633 for Pinus densiflora Community, and 1.0340 for Deciduous broad-leaved Community-II in the ascending order.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.225-237
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• 1990

Various chemical constituents were measured from April to August 1988 at the down-ward 20 stations of Keum River, which is located in the Midwest of Korea, to understand the characteristics of water quality with respect to spatio-temporal variations of each constituent. The 24-hrs continuous measurements with 2-hrs interval were made simultaneously at station 2 near the estuary weir and station 9(Ganggyeong) of 35 km upstream from the weir in April. By the results observed for one day in April at station 2, salinity has a range of $7.88\~22.14\%_{\circ}$ and its temporal variability is identical to the pattern of tidal cycle in the neigh-bouring Kunsan Harbor. However, turbidity shows relatively high values only at an interval of 4~5 hours after the lowest salinity time, though hourly fluctuation of pH is very small. Silicate and dissolved inorganic nitrogen have inversively linear correlationships with salinity, implying the concentration of the two nutrients strongly regulated by estuarine mixing of sea and river waters. In contrast, phosphate sustains roughly a constant level over a wide salinity range and distinctly lower values than those corresponding to nitrate in the oceans. Such distributions of phosphate have been observed in some estuaries, and interpreted as driven by removal of dissolved phosphate into bottom sediments and the bufforing of phosphate by particulate matter. COD values at station 2 are relatively high in day-time(particularly afternoon) and in high-salinity periods. At station 9, saltwater intrusion was never found but water level changed to the extent of 2.5 m for one day. Although each parameter at this station exhibits very slight variations in their abundance for 24 hours compared with station 2, the contents of COD, silicate and ammonia are significantly higher than at station 2. Concentration of suspended matter is relatively high in the brackish water region up to $\~20$ km above the river mouth, probably due to strong tidal stirring of the bottom de-posits. Also, relatively high pH, COD and $O_2$ saturation at the upward stations of $40\~50$ km from the weir are presumably attributable to active photosynthesis of plants in the region. In general, COD and nutrients except phosphate are higher values at the upper stations than in the estuary zone, and show the highest abundances in July nearly at all stations. Finally, in the estuarine region tidal mixing of sea-river waters seems to be an important factor controlling the distributions of turbidity, COD, silicate and nitrate as well as salinity. However, water quality in the upward fresh-water zone is remarkably variable according to months or seasons.

• Korean Journal of Ichthyology
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• v.2 no.1
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• pp.53-62
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• 1990

Morphological development from egg to juvenile stages of the trident goby, Tridentigertrigonocephalu5 were observed in the laboratory at Pusan, Korea. The ripe eggs were spherical in shape, measuring 0.49-0.62 mm in diameter. The eggs became ellipsoid shape after the insemination and measured about 1.40-1.58 mm on the long axis. Hatching began about 158 hours after insemination at water temperature of $20.5-24^{\circ}C$. The newly hatched larvae were 2.88-3.14 mm in total length(TL), with 27-28(10+ 17-18) myomeres. Many melanophore and guanophores are distributed on eye cups, gas bladder, optic vesicle, intestine and the caudal region. Three days after hatching the yolk and oil-globule was completely absorbed and the larvae attained a total length 3.26-3.62 mm. The larvae swam actively in the aquarium and fed on the rotifer. Ten days after hatching, the larvae averaged 5.20 mm in TL and the caudal notochord flexed at $45^{\circ}$. Twenty days after hatching, the larvae averaged 7.47 mm in TL and rudimental anal, second dorsal, caudal and pectoral fins were formed. The larvae attained 12.05-12.65 mm in TL thirty five days after hatching and are found to transit the bottom-life, and first dorsal and ventral fins are completely formed. The larvae reached the juvenile stage at 45-50 days after hatching and attained 15.85-16.95 mm in TL, and all scales appeared on the body.

• Korean Journal of Ichthyology
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• v.3 no.1
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• pp.1-10
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• 1991

Spawning behavior and development of eggs and larvae of Mugilogobius abei were observed in the laboratory at Pusan, Korea. The adult male of Mugilogobius abei was observed making nest-like spawning-bed to lay eggs and showing territorial and courtship behaviors. The eggs were transparent and spherical in shape, measuring 0.40~0.50 mm in diameter. They have a bundle of adhesive filaments at their basal end and a cluster of small oil globules. The eggs became ellipsoid shape after the insemination and measured about 0.93~0.96 mm on the long axis. Hatching began about 110 hours after fertilization at water temperature of $24.5{\sim}25.5^{\circ}C$. The newly hatched larvae were 2.04~2.10 mm in total length, with 24~25(8~9+16) myomeres. Many melanophore and guanophore are distributed on eye cups, gas bladder, optic vesicle and the caudal region. Four days after hatching the yolk and oil-globule were completely absorbed and the larvae attained a total length 2.20~2.35 mm. The larvae swam actively in the aquarium and start to practice feeding on the rotifer. Twelve days after hatching, the larvae averaged 3.20 mm in TL and the caudal notochord flex at $45^{\circ}$. Rudimental second dorsal, anal, caudal and ventral fins are also formed. The larvae attained 10.40~10.80 mm in TL, 35 days after hatching, are found to start the bottom-life after having completely formed first dorsal and ventral fins. The larvae reached the juvenile stage at 50~60 days after hatching and attained 15.37~20.25 mm in TL. At this period all scales appeared on the body.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.2
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• pp.70-80
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• 2011

Estuarine ecosystem responds sensitively to natural and anthropogenic perturbations. lt is necessary to identify the direction of the change when the perturbation occurs as well as to understand the structure and functioning of estuarine ecosystem for a proper management of the area. In this study, the estuarine habitats were classified into different ecological districts so as to the switch from one district to another district could be related to the environmental change due to the perturbations. Total 16 ecological districts was defined according to the presence of barrage, salinity and vegetation characteristics. The defined ecological districts were applied to small estuaries in Goseong bay, south sea of Korea (Baedun, Guman, Maam, Goseong) to distinguish different regions which might have characteristic bottom topography, inclinations of river bottom, sediment characteristics, salinity structure and area of vegetation. Total 7 out of 16 ecological district was identified in this region; NFB (natural, fresh, bare), NHB (natural, high salinity, bare), NLV (natural, low salinity, vegetated) in natural (without barrage) estuaries and CFB (closed, fresh, bare), CFV( closed, fresh vegetated), CLV (closed, low salinity, vegetated), CHB (closed, high salinity, bare) in closed (with barrage) estuary. A comparison of environmental factors and biota between CHB and CLV demonstrated the effect of barrage on estuarine ecosystem. The height and sediment characteristics of CHB and CLV were similar but the average salinity was lower in CLV than in CHB due to the barrage, which produced favorable condition for the Phragmites australis in CLV. Information regarding the ecological districts in various sizes and location could be useful for predicting the ecosystem change due to natural and anthropogenic perturbations and for preparing management actions.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.14 no.2
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• pp.155-160
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• 2011

Purpose: This study was performed to evaluate the role of colonoscopy in children with hematochezia. Methods: We retrospectively reviewed the medical records of 277 children who underwent colonoscopy because of hematochezia between January, 2003 and July, 2010. Results: The mean age of the patients was $6.0{\pm}4.4$ (7 days~17.8 years) years. The male to female ratio was 2.2:1. The duration between the 1st episode of hematochezia and colonoscopy was $4.9{\pm}12.1$ months. Characteristics of hematochezia included red stool (65.1%), blood on wipe (12.8%), bloody toilet (11.9%), and blood dripping (10.2%). The most proximal region of colonoscopic approach was terminal ileum (84.5%), cecum (9.5%), hepatic flexure (2.8%), and splenic flexure (3.2%). Eighty five patients (30.6%) had no specific abnormal findings. Major causes of hematochezia were polyp (26.4%), food protein induced proctocolitis (6.9%), infectious colitis (5.4%), lymphofolliculitis (5.7%), non specific colitis (5.7%), and vascular ectasia (5.1%). The hemorrhagic sites included the rectum (24.0%), rectosigmoid junction (18.1%), sigmoid colon (13.5%), ascending colon (14.2%), transverse colon (11.3%), descending colon (7.8%), cecum (8.1%), and terminal ileum (3.1%). The recurrence rate of hematochezia after colonoscopy was 19.1%. Colonoscopy was performed in 262 patients (94.6%) with conscious sedation. Endoscopic hemostasis was performed in 5 patients. Complications of colonoscopy or sedation were not found. Conclusion: The causes and lesional localization of pediatric hematochezia were diverse. Colonoscopy has an important role in the diagnosis and treatment of hematochezia in children. Total colonoscopy is recommended to detect the cause of hematochezia.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.45-58
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• 2012

For the development of reference values and evaluation of water quality in various environmental conditions, we divided the coastal region around Korean peninsular into 5 distinctive ecological regions based on the influence of surface current, depth, tidal range, turbidity, and climate condition. We used national marine environment monitoring data collected by National Fisheries Research & Development Institute(NFRDI) from 2000-2009. For the reference values, we used maximum seasonal mean from 2000 to 2007 for DIN, DIP, and chlorophyll-a and minimum seasonal mean for secchi depth measured at stations without the influence of river runoff in each ecological regions. For the reference value of bottom dissolved oxygen saturation, we used minimum mean value of 90% calculated from minimal riverine influence stations of whole regions. We calculated enrichment score for each assessment criteria. The enrichment score of DIN, DIP, and Chlorophyll-a was 1 (=< reference value), 2 (< 110% of reference value), 3 (< 125% of reference value), 4 (< 150% of reference value), and 5 (> 150% of reference value). The enrichment score of DO saturation and Secchi depth was 1 (> reference value), 2 (> 90% of reference value), 3 (>75 % of reference value), 4 (> 50% of reference value), and 5 (< 50% of reference value). We calculated water quality index using weighted linear combination of five enrichment score for the comparison of whole regions. From the water quality index distribution calculated from all stations between 2000 and 2007 period, we classified into 5 grade based on the standard deviation calculated from total water quality index. We assigned grade very good(I), good(II), moderate(III), bad(IV), and very bad(V) when the water quality index was less than 23, minimum + 1 sd, +2 sd, +3 sd, and grater than minium+ 3 sd, respectively.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.35-42
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• 2006

Experimental study was conducted to identify the active agent for reductive dechlorination of TCE in cement/Fe(II) systems. Several potential materials-hematite (${\alpha}-Fe_2O_3$), lepidocrocite (${\gamma}$-FeOOH), akaganeite (${\beta}$-FeOOH), ettringite ($Ca_6Al_2(SO_4)_3(OH)_{12}$)-that are cement components or parts of cement hydrates were tested if they could act as reducing agents by conducting TCE degradation experiments. From the initial degradation experiments, hematite was selected as a potential active agent. The pseudo-first-order degradation rate constant ($k\;=\;0.637\;day^{-1}$) for the system containing 200 mM Fe(II), hematite and CaO was close to that ($k\;=\;0.645\;day^{-1}$) obtained from the system containing cement and 200 mM Fe(II). CaO, which was originally added to simulate pH of the cement/Fe(II) system, was found to play an important role in degradation reactions. The reactivity of the hematite/CaO/Fe(II) system initially increased with increase of CaO dosage. However, the tendency declined in the higher CaO dosage region, implying a saturation type of behavior. The SEM analysis revealed that the hexagonal plane-shaped crystals were formed during the reaction with increasing degradation efficiency, which was brought about by increasing the CaO dosage. It was suspected that the crystals could be portlandite or green rust ($SO_4$) or Friedel's salt. The XRD analysis of the same sample identified the peaks of hematite, magnetite/maghemite, green rust ($SO_4$). Either instrumental analysis predicted the presence of the green rust ($SO_4$). Therefore, the green rust ($SO_4$) would potentially be a reactive agent for reductive dechlorination in cement/Fe(II) systems.

• Journal of the Korean Society of Radiology
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• v.9 no.6
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• pp.393-401
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• 2015

Radiation therapy for lung cancer is an effective treatment during monotherapy or combination therapy. Studies have reported that the optimum utilization rate of radiation therapy is estimated at 61% to 74%. Radiation therapy in Korea has been investigated to be low; further studies are needed. This study was intended to assess the appropriateness of the use of radiation and to reveal the use of radiation therapy-related factors by examining radiation therapy in lung cancer patients of Busan and South Gyeongnam Province. This study was aimed at the population diagnosed with lung cancer in Busan and South Gyeongnam Province. To conduct the study, 1036 patients enrolled in two hospitals were collected and 897 appropriate as subjects were selected. We compared the optimum utilization rate and actual rate of radiation therapy, and revealed the adequacy and related factors for use of radiotherapy. Of 897 patients, 503 (56%) were treated with medical therapy and 394 (44%) were given radiotherapy. The radiotherapy utilization rate of all lung cancer patients was 42%. The proportion of non-small cell lung cancer by histologic type was 33% and that of small cell lung cancer was 90%. Factors related to radiation therapy used in cancer were age, histological type, clinical stage, doctor refereed to, and clinical examination. Compared to radiation utilization by region (site), curative chest therapy was 42%; palliative treatment was 26%. In the comparison of histologic types, utilization of small-cell lung cancer is lower; the lowest especially in the stage III. Utilization of radiation therapy in Busan and South Gyeongnam Province was lower than the reasonable one. Utilization difference could be explained by patient factors, tumor factors, and health service factors. To improve utilization,development ofoutreach service programs and activation of the multidisciplinary team are required.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.451-465
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• 2015

The free-air anomalies are computed using a data set from various types of gravity measurements in the Korean Peninsula area. The gravity values extracted from the Earth Gravitational Model 2008 are used in the surrounding region. The upward continuation technique suggested by Dragomir is used in the computation of the external free-air anomalies at various altitudes. The integration radius 10 times the altitude is used in order to keep the accuracy of results and computational resources. The direct geodesic formula developed by Bowring is employed in integration. At the 1-km altitude, the free-air anomalies vary from -41.315 to 189.327 mgal with the standard deviation of 22.612 mgal. At the 3-km altitude, they vary from -36.478 to 156.209 mgal with the standard deviation of 20.641 mgal. At the 1,000-km altitude, they vary from 3.170 to 5.864 mgal with the standard deviation of 0.670 mgal. The predicted free-air anomalies at 3-km altitude are compared to the published free-air anomalies reduced from the airborne gravity measurements at the same altitude. The rms difference is 3.88 mgal. Considering the reported 2.21-mgal airborne gravity cross-over accuracy, this rms difference is not serious. Possible causes in the difference appear to be external free-air anomaly simulation errors in this work and/or the gravity reduction errors of the other. The external gravity field is predicted by adding the external free-air anomaly to the normal gravity computed using the closed form formula for the gravity above and below the surface of the ellipsoid. The predicted external gravity field in this work is expected to reasonably present the real external gravity field. This work seems to be the first structured research on the external free-air anomaly in the Korean Peninsula area, and the external gravity field can be used to improve the accuracy of the inertial navigation system.