• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1630-1637
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• 2008

Jeju-do is a island formed by the volcanic activity and has more than 360 volcanic cones distributed widely along the long axis of the elliptically shaped island. The volcanic cones consist mainly of scoria, so called "Song-I" in the local dialect. In this study the chemical and soil mechanical properties of scoria being very different from those of the inland were investigated with the various tests. In the sieve-passing test the particle size of scoria had more than 10 of uniformity coefficient and gradation coefficient of 1 ~ 3, showing relatively homogenous distribution. Based on the uniformity classification, scoria was assorted into GW. In the large scale direct shear tested for measuring the mechanical strength of scoria the internal friction angle of red scoria was $37^{\circ}$ and that of black scoria was $36^{\circ}$. This indicated that there was no difference in the mechanical strength between two types of scoria. On the other hand, red and black scoria had $1.24{\times}10^{-3}$ to $3.55{\times}10^{-2}$ cm/sec of k values for the static water level permeability, thus being classified into a coarse or fine sand as compared with that representing the saturated soil. They also had 1.411 to $1.477\;g/cm^3$ of notably low $r_{dmax}$ values for the compaction test as compared with common soil, which was considered to be due to their low specific gravity and high porosity. In conclusion, the soil mechanic properties of scoria obtained from this study are thought to be very helpful for reducing lots of trial and error happening in the civil engineering construction.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.199-206
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• 2024

A single specimen belonging to the family Carangidae was first collected by angling in Seogwi-dong, Seogwipo-si, Jeju-do on 16 October 2023. This individual was identified as Caranx papuensis Alleyne & MacLeay based on morphological traits as following: lateral line gently curving below the first dorsal fin, presence of scaleless area on the thorax, and gill rakers 26. A total of 619 base pairs sequences of the mitochondrial DNA cytochrome c oxidase subunit I region was analyzed, and we found it closely matched to the Japanese C. papuensis (K2P distance=0.54%). We propose its new Korean name "Hwang-jul-jeon-gang-i" based on a yellow band along the lateral line.

• Parasites, Hosts and Diseases
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• v.50 no.4
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• pp.287-293
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• 2012

Knowledge of the prevalence of human Toxoplasma gondii infection is required in the Republic of Korea. In this study, we surveyed the seroprevalence of T. gondii infection and analyzed the risk factors associated with seropositivity among residents in 2 administrative districts; Seoul and the island of Jeju-do, which have contrasting epidemiologic characteristics. Sera and blood collected from 2,150 residents (1,114 in Seoul and 1,036 in Jeju-do) were checked for IgG antibody titers using ELISA and for the T. gondii B1 gene using PCR. In addition, participants completed a questionnaire that solicited information on gender, age, occupation, eating habits, history of contact with animals, and travel abroad. The T. gondii B1 gene was not detected in all residents examined. However, ELISA showed 8.0% (89 of 1,114 sera) positive for IgG antibodies against T. gondii in Seoul and 11.3% (117 of 1,036 sera) in Jeju-do. In both districts, the positive rates were higher in males than in females, and those 40-79 years of age showed higher rates than other ages. In Seoul, residents older than 70 years of age showed the highest positive rate, 14.9%, whereas in Jeju-do the highest prevalence, 15.6%, was in those in their sixties. The higher seropositive rate in Jeju-do than in Seoul may be related to eating habits and occupations. The present results and a review of related literature are indicative of an increased seroprevalence of T. gondii in Korea in recent years.

• Journal of Marine Bioscience and Biotechnology
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• v.13 no.1
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• pp.48-57
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• 2021

Vibrio species are Gram-negative basophils that are ubiquitous in seawater, increasing in number as the water temperature increases. Humans are usually infected by the consumption of contaminated seawater or seafood. V. alginolyticus infection in humans is mainly associated with infections of the skin and ears, such as acute otitis media and cellulitis. In this study, the distribution of V. alginolyticus along the coast of Jeju Island, and its relationship with water temperature, salinity, DO, and pH was investigated. The antibiotic susceptibility of the bacteria isolated was also tested. In seawater, the Daejeong area had the highest detection rate, with 13 cases (21.7%), and the Hallim area showed the lowest detection rate, with eight cases (13.3%) in. In shellfish, the Daejeong area had the highest rate, with seven cases (23.3%), and the Seongsan and Hallim areas had the lowest detection rate, with four cases (13.3%). The overall detection rate was the highest in Daejeong area, with 20 cases (22.2%), and the lowest in the Hallim area, with 12 cases (13.3%). The detection rate was highest when the water temperature was highest.

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.277-281
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• 2017

A single specimen (273.1 mm in standard length) of the monacanthid Thamnaconus tessellatus was caught by one-boat trawl from western Jeju Island and then collected at Busan Cooperative Fish Market (BCFM) on 30 May 2015. The specimen is characterized by both head and body with many dark brown spots densely, posterior margin of caudal fin no black, first dorsal spine originates the posterior half of eye, and 34~37 dorsal fin rays. This is the first record of T. tessellatus in Korea; we therefore add the species to the Korean fish fauna. According to the Yamada et al. (1995), we propose the Korean name, "Nam-byeol-jwi-chi" for this species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.697-703
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• 2018

In 2017, total coliform (TC), fecal coliform (FC) and fecal Streptococci (FS) bacteria were examined in seawater samples collected at coastal sites on Jeju Island (Aewol as a control, Namwon, and Daejeong) and at Pohang (Yeongil as a control, Guryongpo-North, and Guryongpo-South) to examine the correlations between the density of fish farms and distributions of the indicator bacteria. Only a few TC, FC, and FS colonies were detected in all of the samples obtained from Jeju Island. Of note, 2,000 and 1,000 CFU of FS $100mL^{-1}$ were detected in samples from Guryongpo-South in June and August, respectively. Although the total area of approved fish farms located within 5 km of the sampling point at Guryongpo-South is 5-16 times smaller than in other regions, the number of indicator bacteria was highest in this region. Therefore, microbiological pollution in the Guryongpo-South region might be due to sources other than the effluent released from nearby fish farms.

• Journal of Nutrition and Health
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• v.10 no.1
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• pp.49-58
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• 1977

Nutrition counselors in Korea often encounter difficulty in their attempt to change village women's attitudes regarding food taboos which are counter to good eating habits. There are a great many food superstitions which are not due to religious influence, but seem to be related to shape and composition of food. Many expectant mothers superstitiously avoid eating certain foods for fear that they may cause mental or physical abnormality in their babies. As was shown in a previous survey (Mo, 1966)of villages in all provinces except Jeju Island, such superstitions were common among pregnant and lactating mothers. Many food taboos and superstitions based on non-scientific and irrational ideas do exist even in modern society, and are a major obstacle to nutritionally adequate food consumption. A study of food taboos among women of Jeju Island was undertaken from November to December of 1976, these results to be compared as well with those of the previous study. There were 73 items found to be prohibited during pregnancy. Of these, 48.7% were of the deaf group, 17.4% fish, 5.5% eggs, 4.7% cereal, and only 2.2% fruit. Of 252% women respondents, 111 (45% ) abstained from eating chicken, duck, and shark because of the belief that they would cause their babies to be born with gooseflesh or shark skin. Many of them avoided rabbit meat for fear that their babies might be born with harelip. It was also feared that a baby would become disfigured if his mother ate duck, goat, dog meat, chicken or duck eggs, or soup made of bones. A common superstition was that highly spiced or salty foods would cause the fetus to be hairless. Squid and octopus were believed to cause babies to have weak bones, or none at all. Most of these food taboos were associated with fears concerning Physical structure and appearance of unborn babies. Other taboos were associated with fear of undesirable behavioral characteristics. For example, some mothers thought that a baby would pinch or bite the mother's breast during the weaning period, if crab meat were eaten during pregnancy. Unevenly sliced rice cake, loach, snake meat and eel were also believed to cause a baby to be ill-tempered. The findings of this study are remarkably similar to those of the previous study conducted by the authour in 1966. Most of the same food taboos, based on non-scientific and irrational reasons, were found on Jeju Island as on the peninsula, and thor were similarly wide-spread. The results of correlational analysis show that the most significant factors related to prevalence of food taboos, are level of education and religious background. Number of food taboos is correlated with level of education. Also, food taboos are least freqent among the Christian woman. Proper nutrition education should he undertaken in order to encourage intake of protein-rich food, particularly during pregnancy when nutritional needs of mother and fetus are great.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.236-242
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• 2015

We surveyed the distribution of exotic weeds in the 141 crop fields of Jeju island. The exotic weeds were summarized as 66 taxa including 18 families, 50 genera, 64 species and 2 varieties. In winter crop fields there were 45 species of exotic seeds in 18 families, in summer crop fields 50 species in 16 families, and in perennial crop fields 39 species in 17 families. Total exotic weeds were classified to 39.4% of summer annuals, 36.4% of winter annuals, 7.6% of summer and winter annuals, and 16.7% of perennials. The ratio of summer annuals were high in the summer crop fields. Compositae was dominant family, followed by Gramineae, Malvaceae and Solanaceae. Malvaceae did not appear in perennial crop fields. Dominant exotic weeds in winter crop fields were Chenopodium album, Amaranthus viridis, Senecio vulgaris and Coronopus didymus, in summer crop fields, Chenopodium album, Amaranthus viridis, Senecio vulgaris and Sonchus oleraceus and in perennial crop fields, Conyza sumatrensis, Gnaphalium calviceps and Senecio vulgaris. The dominant exotic weeds in the crop fields of Jeju island were Chenopodium album, followed by Amaranthus viridis, Senecio vulgaris, and Conyza sumatrensis. This information could be useful for establishment of exotic weed control methods in Jeju island.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.295-304
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• 2012

This study proposed a two-dimensional horizontal numerical model based on the nonlinear shallow water wave equations to simulate tsunami propagation and coastal inundation. We numerically investigated the possible impacts of tsunami caused by the triple interlocked Tokai, Tonankai and Nankai Earthquakes on the Jeju coastal areas, using the proposed model. The simultaneous Tokai, Tonankai and Nankai Earthquakes were created a virtual tsunami model of an M9.0 earthquake. In numerical analysis, a grid nesting method for the local grid refinement in shallow coastal regions was employed to sufficiently reproduce the shoaling effects. The numerical model was carefully validated through comparisons with the data collected during the tsunami events by 2011 East Japan Earthquake and 1983 central East Sea Earthquake (Nihonkai Chubu Earthquake). Tsunami propagation triggered by the combined Tokai, Tonanakai and Nankai, Earthquakes was simulated for 10 hours to sufficiently consider the effects of tsunami in the coastal areas of Jeju Island. The numerical results revealed that water level fluctuation in tsunami propagation is greatly influenced by water-depth change, refraction, diffraction and reflection. In addition, the maximum tsunami height numerically estimated in the coastal areas of Jeju Island was about 1.6 m at Sagye port.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.268-274
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• 2007

Traditional two-dimensional (2D) interpretation of magnetotelluric (MT) data utilizes only transverse magnetic (TM)-mode data, because 2D inversion of transverse electric (TE)-mode data results in spurious features when 3D structures exist in the subsurface. The application of a 3D inversion algorithm to a single MT profile can reduce contamination due to off-profile anomalies and help us to incorporate TE-mode data in the interpretation. In this study, we conduct 2D and 3D inversions of MT data observed along two lines in Jeju Island. First, we invert apparent resistivities and phases in the TM and TE modes separately. Then, we perform 2D joint inversion of both TM- and TE-mode data and 3D inversion of both Zxy- and Zyx-mode data corresponding to TE- and TM-mode data in 2D. The resistivity images derived from all four data show that the geoelectrical structure in Jeju Island is a three-layered earth with the resistive-conductive-resistive stratigraphy within a depth of 5 km. The 3D inversion does not produce clear anomalies in the reconstructed profile image, while all of 2D do. This attributed to the possibility that 2D inversion results are distorted by exiting off-profile 3D anomalies in Jeju. With 3D inversion of 2D profile MT data, we can deduce more reliable results that are not seriously distorted by off-profile 3D anomalies.