• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.551-555
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• 2006

In this study, new dispersion-correction terms are added to a leap-frog finite difference scheme for the linear shallow-water equations with the purpose of considering dispersion effects of the linear Boussinesq equations for propagation of tsunamis. The numerical model developed in this study is tested to the problem that the initial free surface displacement is a Gaussian hump over a constant water depth, and the predicted numerical results are compared with analytical solutions. The results of the present numerical model are accurate in comparison with those of existing models.

• Korean Journal of Environment and Ecology
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• v.17 no.1
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• pp.18-25
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• 2003

In order to know the effects of PCB(Arochlor 1248) on the oocyte maturation and proges-terone(P$_4$) production by FPH(Frog pituitary homogenate: 0.01 p.e/$m\ell$) of frog in vitro, the oocytes were cultured for 20 hours in presence of the PCB at various concentrations and exam-ined their maturation(germinal vesicle breakdown: GVBD) rates and P$_4$ levels secreted by the oocyte in the culture medium. The results show that PCB concentration of 10 ppb suppressed the maturation of the oocytes and secretion of P$_4$. To examine the reversibility of the inhibitory effects, the oocytes were exposed to the PCB only for 3 hours, and then transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the PCB when they were exposed to 2.5 ppb, but not to 5 ppb of the PCB. These results indi-cate that PCB suppress the maturation of oocytes and secretion of p, at low concentration, sug-gesting that the frog oocyte culture system can be used as a useful tool to evaluate the toxicity of the pollutants in the environment.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.413-420
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• 2003

A gas chromatography/mass spectrometric assay method was developed for the simultaneous determination of neutral and bacis twenty-five disruptors $(ED_S)$ in frog and fish. Afther homogenization and sonication of 5 g of sample, purification was achieves in one step with a solid phase extraction procedure using silica gelflorisl. Eluton was performed with 50mL of acetone : n-hexane (1 : 9) solution. The eluate was concentrated to approximately 10uL and dissolves with 100 uL of hexane and analyzed by GC-MS (SIM). The peaks had good chromatographic properties and the extraction of these compounds from sample also gave relatively high recoveries with small variatoins. Detection limits were 0.1 ng/g for 4-nitrotoluene, benzophenone, hexachlorobenzene, atrazine, malathion, o,p-DDT, o,p-DDT and permethrin, and 0.2 ng/g for heptachlor epoxide, γ-chlordane, α-chlordane, p,p'-DDE, p,p'-DDD, cypermethrin and fenvalerate, and 0.3 ng/g for trifluralin, metribuzin, alachlor, dieldrin and p,p'-DDT, and 0.5 ng/g for heptachlor, aldrin and parathion, and 0.7 ng/g for endrin, and 0.8 ng/g for nitrofen. The recoveries were between 33 and 109%. The method was used to analyze twenty-five frogs and forty-six fishes fishes samples caught from various regions in Korea. Benzophenone was detected at concentration of up to 17.2 ng/g in frog or fish. Heptachlor, aldrin, γ-chlordane, p,p'-DDE, p,p'-DDD, endrin and o,p-DDD were detected at concentrations of 0.7-12.5 ng/g in frog or fish. Also significant leveles of dieldrin (up to 22.5 ng/g) were observed. The developed method may be valuable to be used to the national monitoring project of EDS in biota samples.

• The Korean Journal of Physiology
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• v.7 no.1
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• pp.41-47
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• 1973

$Na^{+}$ balance was studied in Rana temporaria, which hibenates in fresh water in the winter time. $Na^{+}$ uptake rate, skin $Na^{+}$ loss rate, urinary $Na^{+}$ loss rate and $Na^{+}-K^{+}$ adenosine triphosphatase(ATPase) were measured at two different temperatures $1{\sim}2^{\circ}C\;and\;20{\sim}24^{\circ}C$ respectively. The results obtained were as follows: 1. $Na^{+}$ uptake rates in the frog in an artificial Pond water (APW) were found to be $8.28{\pm}0.73\;and\;2.19{\pm}0.37\;{\mu}Eq/g/day\;at\;20{\sim}24^{\circ}C\;and\;1.0{\sim}2.5^{\circ}$ respectively. 2. $Na^{+}$ loss rate through the frog skin to APW were found to be $4.26{\pm}0.72\;and\;0.93{\pm}0.21\;{\mu}Eq/g/day$ at the same temperatures. 3. Mean rates of urinary $Na^{+}$ loss at $20{\sim}24^{\circ}C\;and\;3{\sim}4^{\circ}C$ were found to be $3.02{\pm}0.73\;and\;0.78{\pm}0.13\;{\mu}Eq/g/day$ respectively. 4. The activities of $Na^{+}-K^{+}$ activated ATPase of frog skin fragments were found to be $258{\pm}39.4\;and\;49.6{\pm}7.1\;{\mu}M\;Pi/g$ protein/hr at $24^{\circ}C\;and\;2^{\circ}C$ respectively. From the above results, it may be concluded that frogs can take up enough $Na^{+}$ through the skin from APW exceeding skin loss Plus urinary loss at $1{\sim}2^{\circ}C$. It is suggested that $Na^{+}$ transport across frog skin is closely related with $Na^+-K^+$ ATPase since $Q_{10}\;of\;Na^{+}$ uptake is much similar to that of the activities of $Na^{+}-K^{+}$ ATPase.

• The Korean Journal of Physiology
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• v.11 no.2
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• pp.1-7
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• 1977

The activity of the $Ca^{++}$ activated adenosinetriphosphatase (Ca-ATPase) of actomyosin systeme of rabbit and frog skeletal muscle has been studied at varying pH and temperature. The PH optima of the Ca-ATPase activity of the rabbit actomyosin was rather broad. Over the temperature range of $16-36^{\circ}C$ activity of the enzyme was not appreciably changed between pH 6.4-8.5; below and above which it rapidly reduced. The pH at the inflection point of the enzyme activity increased as temperature decreased, showing the ${\bigtriangleup}pH\;inflection/{\bigtriangleup}T$ of approximately $-0.018\;unit/^{\circ}C$. Consequently, $(OH^-)/(H^+)$ ratio at the inflection point was constant regardless of assay temperature. In the frog actomyosin systems the Ca-ATPase activity was not apparently altered between PH 6.4-7.0 when the incubation temperature was $15{\sim}30^{\circ}C$. Outside of this range of pH, however, the enzyme activity was dramatically decreased. The pH of the inflection point changed inversely with temperature. ${\bigtriangleup}pH\;inflection/{\bigtriangleup}T$ at the acidic side was approximately $-0.018\;unit/^{\circ}C$, whereas that at the alkaline side it was about $-0.037\;unit/^{\circ}C$. The Arrhenius Plot on the Ca-ATPase activity at constant $(OH^-)/(H^+)$ ratio of 1.0 was not linear, but showed break at arround $20^{\circ}C$ for both rabbit and frog actomyosin Preparations. From these results it was speculated that pH dependence of Ca-ATPase activity of rabbit actomyosin systems might reflect titrations of histidine-imidazole and -SH groups, and that of the frog actomyosin represents titrations of histidine-imidazole and lysyllysine ${\alpha}-NH_2$ groups.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.121-126
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• 2007

We monitored gold-spotted pond frog (Rana chosenica) populations near the Korea National University of Education in Chungbuk, Korea, from 19 May to 8 August, 2006 to examine the spatial distribution of populations in local areas and to investigate patterns of migration of adult gold-spotted pond frogs from terrestrial hibernation sites to breeding sites, We captured individuals from the largest population using a drift fence with 22 pitfall traps surrounding the breeding site. A total of 22 individuals (19 males and 3 females) were captured between 23 May and 15 June. No peak in breeding migration was detected, but the onset of the breeding migration may correspond with increased humidity. Male body weights were negatively correlated with sampling dates. Seven of 22 individuals were captured at the 4th pitfall trap, which was placed between two culverts. The capture rate per pitfall trap was higher in traps close to the rice field banks (1.44, traps $1{\sim}9$) than in traps facing hilly land (0.33, traps $13{\sim}18$). Comparative data from the Korean frog (Rana coreana), a sympatric species in the study area, were also collected and compared with those of the gold-spotted pond frog.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.145-159
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• 2010

A Sustainable Structured wetland Biotop (SSB) system was planned, designed, and finally constructed, and maintained in the An-teo Reservoir ecological park, which is the habitat of the endangered Gold-spotted Pond Frog. The system purifies polluted water of An-teo Reservoir which flows from up to bottom within the system. Water was sampled once a month at the inlet and at the outlet from December, 2009 to August, 2010. BOD5, SS, T-N and T-P were analyzed. Average influent and effluent BOD5 concentration was 2.9 and 1.0 mg/L, respectively, and BOD5 removal was 67%. SS concentration of influent and effluent averaged 18.1 mg/L and 2.5 mg/L, respectively, and SS abatement amounted to 86%. Average influent and effluent T-N concentration was 0.426 mg/L and 0.147 mg/L, respectively, and T-N retention was 66%. T-P concentration of influent and effluent averaged 0.071 mg/L and 0.022 mg/L, respectively, and T-P removal amounted to 68%. Plant and frog species of the system were monitored during the period. Amphibia and reptiles provided 7 species and 4 families including the Endangered Gold-Spotted Pond Frog (Rana chosenica ) which also lives in the system. Twenty-six plant species were naturally introduced into the system, however, they didn't make up a significant portion of the plant populations compared with the planted species. The endangered plants, Bladderwort (Utricularia vulgaris var. japonica ) and Euryale ferox were observed in An-teo Reservoir as well as in the system.

• Journal of Information Processing Systems
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• v.13 no.2
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• pp.370-384
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• 2017

The image segmentation is the most important operation in an image processing system. It is located at the joint between the processing and analysis of the images. Unsupervised segmentation aims to automatically separate the image into natural clusters. However, because of its complexity several methods have been proposed, specifically methods of optimization. In our work we are interested to the technique SFLA (Shuffled Frog-Leaping Algorithm). It's a memetic meta-heuristic algorithm that is based on frog populations in nature searching for food. This paper proposes a new approach of unsupervised image segmentation based on SFLA method. It is implemented and applied to different types of images. To validate the performances of our approach, we performed experiments which were compared to the method of K-means.

• Applied Microscopy
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• v.25 no.1
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• pp.86-95
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• 1995

This study was accomplished to investigate the ultrastructure of mucous glands in dorsal skin of frog (Rana catesbeiana) by means of scanning and transmission electron microscopes. The dorsal skin of Rana catesbeiana is composed of epidermis and dermis. The cutaneous mucous glands consist of inner glandular epithelial cells and outer myoepithelial cells. Glandular epithelial cells are divided into four types by the microscopic ultrastructure; ER-rich cell, round secretory granule-containing cell, foam-like granule mass-containing cell, mitochondria-rich cell. Myoepithelial cell has a long elliptical nucleus and filled with fibrous materials in the cytoplasm. As a result of scanning microscopic observation, the surface of dorsal skin is covered with cutaneous protrusions. The opening sites of the mucous glands are irregularly distributed in dorsal skin.

• The Journal of Korean Physical Therapy
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• v.7 no.1
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• pp.1-8
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• 1995

The purpose of this study was to determine the effects of high voltage pulsed current(HVPC) and low voltage pulsed current(LVPC) on posttraumatic edema formation in frog hind limbs In this study, 16 bullfrogs(Rana Catesbeiana), weighting 189g to 340g were used. Limb 16 anesthetized bullfrogs were systemically injuried by weight drop. One hind limb of each frogs was randomly selected to receive continuous 120 pps HVPC and 100 pps LVPC at $90\%$ of motor threshold(HVPC : 33.3v, LVPC : 0.2-1mA). The opposite hind was remained as a control. A series of six 30-minute treatment(interrupted by 30-minute rest) was begun minutes after injury. The results were as follows. 1. Cathodal HVPC has heed shown to be effective in curbing posttraumatic edema formation in frogs, but anodal HVPC did not effect. 2. Volumes of hind limbs treated with LVPC were not significantly different over time from those of untreated hind limbs. 3. Therefore, waveform(HVPC versus LVPC) seems to influence the efficacy of electrotherapy for edema control. 4. Electrical stimulation were not increased edema formation on frog hind limbs.