• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.185-192
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• 2017

Objectives : The aims of present study was to investigate clinical characteristics of male patients with eating disorders. Methods : The present study included 32 male patients with eating disorders and 75 female patients with eating disorders, recruited from an eating disorders specialized clinic in a university hospital, Seoul, Korea. We compared clinical characteristics of eating disorders and comorbid conditions of depression and anxiety between men and women with eating disorders. Correlations between eating disorders psychopathology in men with eating disorders and their weight suppression(WS) were investigated. Results : There was no difference in age at presentation, age of onset, illness duration, and body mass index at presentation between genders. Male patients with eating disorders had higher rates of premorbid overweight or obesity than female patients with eating disorders had. WS in the male patients was associated with the severity of their eating disorders. Conclusions : The present study provides grounds for improved understanding for clinical features of eating disorders in males.

• Korean Journal of Ichthyology
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• v.30 no.1
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• pp.9-17
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• 2018

This study investigated how the larvae of three winter-spawning fishes are adapted in a cold water environment by examining the morphology, digestive system, and swimming ability of larvae from three winter-spawning species (Gadus macrocephalus, Liparis tanakae, Hexagrammos agrammus). Data were collected at hatching and first feeding. The results were compared with repored data on several non-winter-spawning species. Mean total lengths at hatching (${\pm}SD$) were $4.35{\pm}0.11mm$, $5.26{\pm}0.08mm$, and $7.48{\pm}0.35mm$ for G. macrocephalus, L. tanakae, and H. agrammus, respectively. Three winter-spawning fishes had well-developed digestive tracts after hatching than those of non-winter-spawning fish larvae. Yolks were intact until 5 days post-hatching in all three species, indicating that they had longer mixed-feeding periods compared with fishes spawned during other seasons. G. macrocephalus, L. tanakae, and H. agrammus larvae had superior cruise and burst speeds (measures of swimming ability) than non-winter-spawning larvae. We conclude that the unique characteristics of these three winter-spawning species are naturally selected adaptations under lower water temperature in winter.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.301-310
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• 2009

For the comparing of mortality of the resistance and susceptible population of Myzus persicae, etofenprox was treated in the recommended concentration of 200ppm. Mortalities of resistance population were 16.7 and 36.7%, and susceptible population were 86.7 and 86.7% after 24 and 48 hours treatment, respectively. For the detect of cross resistance to other pyrethroids, 6 pyrethroids were examined. Mortalities of susceptible and resistance populations were 90 and 31% to deltamethrin, 92 and 23% to lambda cyhalothrin, 81 and 14% to cypermethrin, 70 and 20% to $\alpha$-cypermethrin, 29 and 28% to fenpropathrin, 84 and 29% to fenvalerate, respectively. It was showed that resistance populations were generally resistive to other pyrethroids. On the other hands, for recognized ecological characteristic of M. persicae susceptible and resistance populations life table was tested on the pepper leaves in the petri dish and on the plant in the pot. This results were showed that intrinsic rate of increase ($r_m$), net reproduction number ($R_0$) and generation time in day ($T_c$) were significantly different between two population in both tested. However, life span and reproduction period were slightly different between them. Otherwise, feeding behaviors were tested using EPG technique with non- and treated etofenprox. First potential drop time of susceptible and resistance population was 73.5 and 257.9 sec with non-treated and 93.3 and 1076.2 sec after treated, respectively. Electrical probing signals were 8.2 and 48.8 times with susceptible and resistance individuals after treated etofenprox, respectively. It was supposed that the resistance is more probings than susceptible population. After treated, total feeding time have more 6,728.9 sec on resistance than 965.5 sec on susceptible population. So, total non penetration time of susceptible population was 3,000 sec longer than resistance population.

• Korean Journal of Ichthyology
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• v.31 no.1
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• pp.7-15
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• 2019

The present study aimed to investigate the influence of starvation on growth, survival and swimming ability of Pacific cod Gadus macrocephalus larvae. Notochord length, musculature height, body depth, gut height and volume of yolk of reared larvae were measured to determine the growth parameters. A significant difference was observed in all morphometric characteristics before 15 DAH (days after hatching). Body depth and volume of yolk of unfed larvae were significantly smaller than those of fed larvae from 9 DAH (P<0.05). Almost all yolk in fed group was consumed at 11 DAH. Survival and growth of larvae were observed to determine the effect of delayed initial feeding (2 DAH, 3 DAH, 4 DAH, unfed). All larvae in the unfed group died by 15 DAH and the larvae in other experimental groups survived until the end of the experiment to 21 DAH. Survival rate was not significantly different between the 2 DAH group ($17.5{\pm}4.27%$) and the 3 DAH group ($20.5{\pm}1.5%$) at 21 DAH (P>0.05). However, there was a significant difference in survival rate between the 3 DAH group and the 4 DAH group ($11.7{\pm}1.52%$) (P<0.05). There was no significant difference in notochord length among the groups fed from 2 DAH, 3 DAH and 4 DAH at 21 DAH (P>0.05). The swimming ability in fed group gradually increased in both cruising and burst swimming speeds, while those abilities in unfed group gradually decreased after reaching the peak at 6 DAH in both cruise ($18.7{\pm}6.56mm/s$) and burst swimming speed ($43.5{\pm}12.65mm/s$).

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.57-63
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• 2005

The digestive apparatus and food of the Korean bitterling, Acheilognathus signifer, from the upper reaches of the Hongcheon River were investigated by examining their gill rakers, pharyngeal teeth, and digestive-tube contents. Gill rakers of the first arch were relatively few (17 to 21, mean = 19) and short (mean = 0.36 mm, SD = 0.035). The 2nd to 5th pharyngeal teeth were well developed, while the first tooth was poorly developed. Gill rakers and pharyngeal teeth were completely formed early in life. The digestive tube was long and arranged in many coils. The digestive-tube contents of Korean bitterling mainly consisted of phytoplankton and detrital microorganisms.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.62-62
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• 2003

최근 연안 자원이 급격하게 감소하고 있고 새로운 양식 대상종으로 평가되고 있는 말쥐치의 대량 종묘생산을 위해서는 수정난 대량확보와 자어기 먹이생물 구명 등의 문제점이 해결되어야 한다. 본 연구자들은 우선 호르몬 처리에 의한 산란유도, 조기성숙유도에 의한 조기산란유도 및 수정난 확보방법을 개발하고, 위내용물 분석을 통한 자어의 초기먹이생물을 구명하고자 하였다. 산란유도를 위하여 hCG, LHRH-a 및 hCG+LHRH-a를 다양한 농도로 처리하여 실험한 결과 모든 실험구에서 67~76%의 수정률을 나타내었으나, 대량의 성숙란을 얻지는 못하였다. 따라서 본 종의 산란특성이 다회성인 점을 감안한다면 500 g 전후의 친어 200~300마리를 1개의 수조에 수용하여 자연산란된 수정란을 수거하는 것이 좋을 것으로 판단되었다. 평균 450 g 정도의 말쥐치 친어를 12월부터 6개월동안 천천히 수온을 상승시켜 자연산란을 유도한 결과, 자연산란기 (6월)보다 2개월 빠른 4월 15일(17$^{\circ}C$로 가온한 지 15일)에 첫 산란이 이루어졌고 1개월간 지속되었다. 초기 사육환경을 구명하기 위한 실험에서는 일반적으로 해산어 종묘 생산에 이용하는 클로렐라＋rotifer 실험군이 클로렐라 단독, 규조류 단독, 규조＋rotifer, 녹조＋copepods등이 번식된 환경보다 생존율에 있어 월등히 높은 결과를 나타내었다. 위 내용물 분석에 의한 사육기간 중 섭식한 주요 먹이생물종은 부화 후 5일부터 20일째까지는 rotifer egg, 부화 10일째는 rotifer egg와 small rotifer, 부화 20일째는 rotifer, Artemia sp., copepods, 부화 25일째부터는 copepods였다. 초기성장은 부화직후 전장 1.95 mm였던 것이 10일째는 2.96 mm, 20일째는 3.89 mm, 30일째는 12.9 mm, 50일째는 35.1 mm를 나타내었다. 그러나 말쥐치 자ㆍ치어가 성장함에 따라 발생하는 지속적인 폐사와 종묘의 수송시 발생하는 폐사를 줄일 수 있는 방법이 추후에 해결되어야 할 것으로 사료된다.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.332-343
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• 2004

This study was conducted to test a possibility of water quality improvement using a filter-feeding bivalve (Corbicula leana). In mesocosm scale (width ${\times}$ length ${\times}$ depth: 3 m ${\times}$ 3 m ${\times}$ 0.5 m), we investigated the changes of dissolved nutrient and particulate matter including both abiotic and biotic seston. Short term (16 days) mesocosm experiment was conducted in two stages: the first stage for 8 days and consecutive 8 days of the second stage. Both treatment and control mesocosm were switched over by translocating mussels from the treatment mesocosm to the control, at 8th days since the start of the experiment. This design made it possible to compare mussel effect on the water quality change more clearly. The high mortality of mussel was observed in the treatment of the first stage, but it decreased rapidly and stabilized on the 8th day to less than< 4 ind $day^{-1}$. Chl. a concentration in the treatment mesocosm of the first and second stage decreased to 71 and 88% of initial concentration, respectively, and suspended solids decreased to 70 and 77%. At those times, average filtering rate were 0.46 and 0.61 mL AFDW $mg^{-1}$ $hr^{-1}$, respectively. Both $NH_3-N$ and dissolved total phosphorus (DTP) concentrations increased with the mussel mortality. $NH_3-N$ concentration was positively correlated with the mussel mortality, while DTP concentration showed negative correlation with it. After translocating mussel from the treatment to the control, $NH_3-N$ concentration significantly increased compared with that of initial control. Although DTP concentration also increased, there was no significant difference relative to that of initial control. These results suggest that application of this filter-feeding bivalve in a eutrophic reservoir could be a potential tool to improve water quality if mussels could acclimatize successfully in early stage of the introduction.

• Ocean and Polar Research
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• v.29 no.2
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• pp.101-112
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• 2007

In order to examine the short-term variations of phytoplankton and heterotrophic protozoa community structures with bloom events, water samples were collected every other day at one site in the coastal water off Incheon, Korea, from August 15-September 30, 2001. $Chlorophyll-{\alpha}$ concentrations varied widely from 1.8 to $19.3\;{\mu}g\;l^{-1}$ with the appearances of two major peaks of $Chlorophyll-{\alpha}$ concentration during the study period. Size-fractionated $Chlorophyll-{\alpha}$ concentration showed that net-size fraction ($>20\;{\mu}m$) comprised over 80% of total $Chlorophyll-{\alpha}$ during the first and second bloom periods, nano-size fraction ($3{\sim}20\;{\mu}m$) comprised average 42% during the pre- (before the first bloom) and post-bloom periods (after the second bloom), and pico- size fraction ($<3\;{\mu}m$) comprised over 50% during inter-bloom periods (i.e. between the first and second bloom periods). Dominant phytoplankton community was shifted from autotrophic nanoflagellates to diatom, diatom to picophytoplankton, picophytoplankton to diatom, and then diatom to autotrophic nanoflagellates, during the pre-, the first, the inter, the second, and the post-bloom periods, respectively. During the blooms, Chaetoceros pseudocrinitus and Eucampia zodiacus were dominant diatom species composed with more than 50% of total diatom. Carbon biomass of heterotrophic protozoa ranged from 8.2 to $117.8\;{\mu}gC\;l^{-1}$ and showed the highest biomass soon after the peak of the first and second blooms. The relative contribution of each group of the heterotrophic protozoa showed differences between the bloom period and other periods. Ciliates and HDF were dominant during the first and second bloom periods, with a contribution of more than 80% of the heterotrophic protozoan carbon biomass. Especially, different species of HDF, thecate and athecate HDF, were dominant during the first and the second bloom periods, respectively. Interestingly, Noctiluca scintillans appeared to be one of the key organisms to extinguish the first bloom. Therefore, our study suggests that heterotrophic protozoa could be a key player to control the phytoplankton community structure and biomass during the study period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.607-613
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• 2018

The aim of this study is to predict the exact time of parturition from analysis and classification of preliminary behavior based on parturition signals in sows. This study was conducted with 12 crossbred sows (with an average of 3.5 parities). Behavioral characteristics were analyzed for duration and the frequency of different behaviors on a checklist, which includes the duration of the basic behaviors (feeding, standing, lying down, and sitting). The frequency of specific behaviors (investigatory behavior, shame-chewing, scratching, and bar-biting) was also recorded. Image information was collected every two minutes for 24 hours before the first piglets were born. As a result, the basic behavior of a sows' standing time (22.6% of the time after 24 h, 24.9% after 12 h) and time lying down (55.9% after 24 h, 66.3% after 12 h) increased over the 12 h period before parturition, compared with the 24 h period before parturition (p<0.01). Feeding (13.42% after 24 h, 4.38% after 12 h) and sitting (8.2% after 24 h, 4.5% after 12 h) tended to decrease during the 12 h before parturition (p>0.05). The sows' investigatory behavior ($11.44{\pm}1.80$ after 24 h, $55.97{\pm}6.13$ after 12 h), scratching ($3.75{\pm}1.92$ after 24 h, $20.99{\pm}5.81$ after 12 h), and bar-biting ($0.69{\pm}0.15$ after 24 h, $3.71{\pm}1.53$ after 12 h) increased in the 12-hour period before parturition, compared with the 24-hour period before parturition (p<0.01). On the other hand, shame-chewing ($2.20{\pm}1.67$ after 24 h, $0.07{\pm}0.01$ after 12 h) decreased compared to the 12-hour period before parturition (p>0.05). Thus, standing, investigatory behavior, scratching, and bar-biting could be used as behaviors indicative of parturition in sows.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.9-18
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• 2016

Histological and morphological development of the digestive tract of sevenband grouper were observed from after hatching to 60 days. Fishes were fed with rotifer (Brachionus rotundiformis) and chlorella (Chlorella ellipsoidea) after hatching from 2 to 20 days rotifer and brine shrimp (Artemia salina) in after 20 days rotifer, brine shrimp and semi-dry artificial diet in after 23 days. Histological and morphological development of ten larvae was observed by paraffin embedding method after fixing in 10% neutral buffered formalin. Sevenband grouper RLG showed characteristics of carnivorous fish by average 0.87. Larvae after hatching can't open the mouth and anus digestive tract was observed in a straight line following yolk sac. Larvae was observed feeding activity by opening the mouth and anus. Metamorphosis started 8 days after hatching. Esophagus divided four layer, and goblet cell was observed in esophagus, mid intestine and rectum. Larvae started cannibalism and it was caused by difference of growth. The inside of stomach was differentiated to cardiac orifice, body of stomach, pyloric stomach, and pyloric caeca. Goblet cell was observed all intestine. Gastric gland differentiated after hatching 28 days in stomach. Secretion of gastric juice was found at stomach and mucosal fold pyloric caeca. Even thought the inside of stomach expended and the number of gastric gland increased consistently and goblet cell in intestine and mucosa became longer, histochemical changes follow couldn't be found during transforming juveniles 38 days after hatching.