• Journal of fish pathology
• /
• v.11 no.1
• /
• pp.69-76
• /
• 1998

An apicomplexan parasite, Perkinsus sp. was observed from the cultured baby clams, Ruditapes philippinarum, collected from the coast of Kochang and Taean (South Korea), where it caused seasonal mortality of clams. Several milky-white cysts were observed on the surface of gill and visceral mass of parasitised clams. The trophozoites of parasite had eccentric nucleus and proliferated by schizogony in gill, mantle, hepatopancrease and reproductive tissues, resulting in the formation of granuloma and the intensive infiltration of hemocytes in the tissues. During incubation in FTM, trophozoites increased in size, resulting in prezoosporangia which appeared as round black spheres when colored with Lugols iodine solution. The prevalence of Perkinsus sp. in clams was Kochang, 73.1%; Taean, 94.8% (during 9-mo. survey) and showed size-dependent infection. Hemacolor kit was useful to reduce time for diagnosis of the trophozoite of Perkinsus sp. that has been responsible of massive motalities in the clam.

• The Korean Journal of Zoology
• /
• v.12 no.1
• /
• pp.13-21
• /
• 1969

韓國産 陸棲貧毛類의 分類學的 硏究의 일련으로서 1965年 $\\sim$ 1966年 및 1968年에 採集된 울릉도 産을 調査한 結果 3科 5屬 10種(Allolobophora caliginosa trapezoides, Eisenia foetida, Pheretima agrestis, Ph. heteropoda, Ph. hilgendorfi, Ph. hupeiensis, Ph. phaselus, Ph. serrata, Ph. sp. 1 Ph. sp. 2)을 報告하였다. 울릉도의 陸棲貧毛類에 관해서는 지금까지 報告된 바 없으므로 이들은 全部 울릉도 未記錄이 되고 이중 Pheretima heteropoda Goto et Hatai 는 韓國 未記錄種이고 Phertima hilgendorfi 는 male pore를 가진 點이 本土産과 比較해서 若干 特異하였다.

• Animal cells and systems
• /
• v.6 no.2
• /
• pp.125-143
• /
• 2002

Heterotrophic flagellates occurring in the marine sediments of Inchon and Ganghwa Island are reported. Fifty-six species from 38 genera were encountered in this survey and two new taxa were recorded: Cyranomonas australis sp. nov. and Gweamonas unicus sp. nov. There was little evidence for endemism because all flagellates including the two new taxa described here have been found from other habitats in Australia which are geographically remote from Korea. This study supports the model that free-living heterotrophic flagellates have a world-wide distribution.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.21-33
• /
• 2012

Survey on the phytoplankton community structure and distribution in the upstream watershed of the East River was carried out during the period from May, 2008 to April, 2009. A total composition of phytoplankton included 159 taxa, consisting of 7 orders, 56 genera, 139 species, and 40 unidenfied species. Among those, the diatoms and green algae were more frequently found during the investigation than the other taxa. Cocconeis placentula, Cymbella minuta, Diatoma vulgare, Melosira varians, Navicula cryptocephala, Scenedesmus acuminatus v. acuminatus, were among the most common. The standing crops of the phytoplankton ranged from 86 cells $mL^{-1}$ to 1,467 cells $mL^{-1}$. The dominant species were Achnanthes minutissima, Asterionella formosa, Aulacoseira ambigua, Cocconeis placentula, Coelastrum microporum, Cyclotella sp., Cymbella affinis, C. minuta, C. tumida, Diatoma vulgare, Fragilaria capucina, F. construens, F. crotonensis, Gomphonema affine, G. clevei, Melosira varians, Merismopedia elegans, Navicula cryptocephala, N. pupula, Nitzschia tryblionella, Oscillatoria anna, O. limosa, O. tenuis v. tenuis, Pediastrum duplex v. reticulatum, Phormidium tenue, Scenedesmus acuminatus v. acuminatus, S. acutus v. acutus, S. ecornis v. ecornis, S. quadricauda v. quadricauda, Spirogyra sp., Stigeoclonium sp., Synedra acus, S. ulna, and Ulothrix sp. The most dominant species was Cymbella minuta. The diversity index, evenness index, and dominance index ranged from 1.58 to 3.10, 051 to 0.95, and 0.22 to 0.74, respectively. The phytoplankton community structure of upstream stations of the survey area was influenced by the effluent of the Doam Lake.

• Korean Journal of Veterinary Research
• /
• v.19 no.1
• /
• pp.57-61
• /
• 1979

This survey conducted to know the species of helminth parasites of cats slaughtered in Daegu during the period from July to September in 1977. A total of 65 cases of internal organs of cats was used for this examination. The results obtained were summarized as follows: 1. Six species of trematodes belong to order digenea were found; Clonorchis sinensis (Cobbolt, 1875), Heteropheys heterophyes nocens (Onji et Nisinio, 1915), Metagonismus yokogawai(Katsurada, 1912), Centrocestus sp. Echinochasmus perfoliattlus (Ratz, 1908), and Echinopharyphium sp. 2. Five species except Clonorchis sinens are firstly recorded in cats in Korea.

• Korean Journal of Veterinary Service
• /
• v.16 no.2
• /
• pp.97-102
• /
• 1993

This study was performed to survey on the prevalence of swine internal parasites at 12 piggeries being operated by the sawdust fermentative pigsty in Kyongnam central area. To investigate the effects of viability of eggs, larva and cysts, temperatures at the underlayer of the sawdust floor and rooms of pens were taken four times each season for one year. In a pig farms which have been operated by the sawdust fermentative pigsty, eggs of Ascar is suum(8.8%), Trichr is suis(18.3%), Oesophagostomum sp(9.4%), Strongyloides ransomi(1.3%), Hyostrongylus sp(3.8%) and Metastronylus apri(2.3%) were detected from 480 heads of Pigs. Cysts and oocysts of Coccidia(12.7%), Balantidium coli(5.4%) were also detected form 480 heads of pigs. The change of the temperature in the pig room was variable between $13^{\circ}C\; to\; 27^{\circ}C$ accord-ing to outside condition, whereas that in underfloor was consistently stable between $28^{\circ}C \;to\; 31^{\circ}C$ which was strictly suitable for the development of eggs, larva and cysts.

• Korean Journal of Environmental Biology
• /
• v.23 no.4
• /
• pp.367-373
• /
• 2005

We conducted a year-long survey in 2000 to examine seasonal fluctuations in the abundance of the demersal copepod Pseudodiaptomus sp., the dominant copepod in the Seomjin River estuary, where the spring tide strongly affects changes in salinity gradients. Pseudodiaptomus sp. was found throughout the year in the entire range of salinities measured, but most individuals appeared at oligohaline conditions below 5.0 psu, and less than $2\%$ were observed in polyhaline conditions above 18.0 psu. The peak abundance occurred during autumn in oligohaline waters, and the density was relatively low during the rainy season in summer. In spring and autumn, copepodites were most abundant in oligohaline waters, although they were also fairly abundant in mesohaline conditions $(5\~18\;psu)$. Females with egg sacs appeared in oligo- and mesohaline waters during spring and autumn but were seldom found in polyhaline conditions throughout the year. Our results indicate that, despite the strong physical influence of the tide, Pseudodiaptomus sp. can manipulate its position to remain at its preferred salinity. We also found that spawning mainly occurred in oligohaline waters twice a year.

• Parasites, Hosts and Diseases
• /
• v.43 no.4 s.136
• /
• pp.161-164
• /
• 2005

A survey was performed in order to determine the infection status of the metacercariae of heterophyid fluke in two goby species, Boleophthalmus pectinirostris and Scartelaos sp., collected from Gangjin-gun, and Shinan­gun, Sooncheon-shi, Jeollanam-do, Republic of Korea. A total of three metacercariae of Heterophyopsis continua was found in only one B. pectinirostris $(10.0\%)$ from Gangjin-gun. Heterophyes nocens metacercariae were detected in 24 B. pectinirostris $(96.0\%)$ and 14 Scartelaos sp. $(63.6\%)$ from Shinan-gun. Heterophyopsis continua metacercariae were found in 11 B. pectinirostris $(44.0\%)$ and 21 Scartelaos sp. $(95.5\%)$ from Shinan-gun. Stictodora fuscata metacercariae were detected in 18 B. pectinirostris $(72.0\%)$ from Shinan-gun. No metacercariae were detected in 20 B. pectinirostris from Sooncheon-shi. From the above results, this study is the first to prove that B. pectinirostris and Scartelaos sp. serve as the second intermediate hosts of some heterophyid flukes in Korea.

• Journal of Korean Society of Transportation
• /
• v.28 no.4
• /
• pp.119-128
• /
• 2010

Mode choice behavior is associated with travelers' latent behavior that is an unobservable preference to travel behavior or mode characteristics. This paper specifically addresses the problem of unobservable factors, that is latent behavior, in mode choice models. Consideration of latent behavior in mode choice models reduces the errors that come from unobservable factors. In this study, the authors defined the latent variables that mean a quantitative latent behavior factors, and developed the combined RP/SP model with latent variables using the mode choice behavior survey data. The data has traveler's revealed preference of existent modes along the Han River and stated preference of new water transit on the Han River. Also, The data has travelers' latent behavior. Latent variables were defined by factor analysis using the latent behaviour data. In conclusion, it is significant that the relationship between traveler's latent behavior and mode choice behavior. In addition, the goodness-of-fit of the mode choice models with latent variables are better than the model without latent variables.

• Journal of Soil and Groundwater Environment
• /
• v.26 no.6
• /
• pp.1-17
• /
• 2021

Self-potential (SP) surveys measure naturally occurring differences in electrical potential in the absence of artificial sources and have been applied to various fields since the first application in mineral explorations. Among various causes of SP occurrences, streaming potential is generated by the flow of groundwater, and makes SP surveys suitable for the exploration of groundwater table fluctuation, fractures, sinkholes and landslide occurrences. Recently, there has been many studies that applied SP surveys to monitor water leakage through dikes and embankments. In this review paper, we first review the characteristics and theoretical backgrounds of streaming potential in saturated or unsaturated porous media to introduce it in the embankment among various application field. After the review of the background theory, we review the past cases of field SP surveys on dikes and embankments and also the characteristics of field streaming potential data in the surveys. Further, by analyzing past studies of qualitative as well as quantitative interpretation of SP survey data, we show the possibility of quantitative interpretation of streaming potential data obtained on dikes and embankments. Consequently, it is hope that this review paper helps researches on SP surveys on dikes and embankments, and provides basis for interpretation methods of the SP data to identify leaked area and further leakage rate (or permeability).