• Korean Journal of Ecology and Environment
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• v.36 no.4 s.105
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• pp.420-426
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• 2003

During a three-year study (2000-2002), dramatic changes in the phytoplankton biomass and high transparency were repeatedly observed during mid-spring in the lower part of the Nakdong River. Rotifers (Brachionus, Keratella, Polyarthra) , sharply increased toward the middle and end of spring. As hydrologic retention time increased (to near 20 days) and water temperature increased from $10^{\circ}C$ to > $20^{\circ}C$ toward the end of spring, small cladocerans noticeably increased. Once phytoplankton biomass passed their peak stage in the mid-spring, a short period (one or two weeks) of relatively low phytoplankton biomass and high Secchi transparencies occurred. Grazing by the zooplankton was highest in spring, thus, it seems that high grazing activities of zooplankton grazing regulated phytoplankton dynamics in the river. The results indicate that the role of zooplankton grazing in controlling the phytoplankton biomass becomes more important during the spring when river water is relatively stagnant.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.177-187
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• 2005

For the comparison of feeding behavior of Nilaparvata lugens among different rice varieties, electrical penetration graph (EPG) technique was used. Ten rice varieties were selected from national-widely recommended rice varieties cultivating in Chungnam province. The correlation between feeding duration and honeydew amount excreted was investigated, and the types of EPG pattern were analyzed among rice varieties. The EPG patterns divided into 6 types according to electrical specific feature, respectively. Type 1 pattern was a searching feeding sites, resting or wandering on a rice plant. Type 2 pattern was appeared when the insect untaken from phloem sieve element. Type 3 pattern was observed when the insect piercing into the rice plant. Type 4 pattern was observed when the insect salivating in rice plant. Type 5 pattern was observed when the insect ingesting from the xylem. Type 6 pattern was observed when the stylet moving in cell. Feeding duration time on Gum-nam was significantly shorter than Dong-jin, Dae-ahn, Dong-ahn, Dae-san. Also, on Gun-nam, it was shown that the brown planthopper did not penetrate the cuticle for a long time. The total number of excreted honeydew droplets by the brown planthopper was the greatest in Dong-jin variety and the least in Gum-nam variety. In proportion to phloem feeding time, the number of honeydew droplets had been increased. According to the results of EPG patterns and honeydew droplets analysis, N. lugens seems to prefer Dong-jin, Dong-ahn, Dae-san, and Dae-ahn to Gum-nam, Da-san, and Nam-chun rice plant variety.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.199-200
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• 2002

관상어 초기자어 사육은 rotifer 개발 전 단계의 달걀 노른자를 갈아서 먹이는 방법에서 벗어나지 못하고, 반죽사료를 제작하여 공급하는 방식을 취하고 있는 실정이다. 그렇지만, 해산 어류의 자치어는 rotifer의 먹이생물로서의 가치가 밝혀진 이후 종묘생산에 있어서 없어서는 안될 정도로 중요한 위치를 차지하고 있다. 이에 해수산 종묘생산에서는 다양한 연구가 수행되고 있는데, 그 분야로는 먹이공급횟수, rotifer 공급밀도, 배합사료의 이용, 일일 섭식량(Gatesoupe and Robin, 1992) 및 소화시간(복소, 1997)등이 있다. (중략)

• Korean journal of applied entomology
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• v.52 no.4
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• pp.409-413
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• 2013

This study was performed to understand whether host-plant feeding had an influence on subsequent prey consumption in the zoophytophagous mirid Nesidiocoris tenuis, which has the potential for biological control of greenhouse whiteflies. Potted plants of paprika and sesame and cotton balls soaked with water were provided to the test insects for 24 h, then, frozen eggs of Ephestia kuehniella were presented to adult mirids for 24 h, and the number of eggs consumed by them was counted. No significant difference in prey consumption was observed between the mirids previously provided with water ($49.2{\pm}30.58$ eggs) or paprika ($55.7{\pm}31.19$ eggs), whereas those previously fed with sesame ate significantly less prey ($24.2{\pm}34.70$ eggs) than the mirids that were provided with paprika or water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.411-422
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• 1986

Diets of the rock trout, Agrammus agrammus, in the shore area of Tongbaeksom, Pusan over the period of July 1981 to June 1982 were studied. Specimens were sampled by angling. Stomach analysis showed that the rock trout fed mainly on epibenthic food in the littoral zone along the coast of Tongbaeksom. The food organisms of the enviornment were studied by means of underwater sampling around the angling area for this study. Although the food items of the fish changed slightly with season and age-group, main food items were Amphipoda (Gammaridae, Caprellidae) and Isopoda (Sphaeromidae, Idotheidae). This suggests that the diets of A. agrammus mainly comprised epibenthic food. Food diversity increased with age. The fish almost consummed on smaller food in size, but had selective predation according to food size, i. e. on larger food as age increases. These data provide additional support for the importance of the detritus-benthos-consummer type food chain.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.207-211
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• 1981

It has been documented that the resistance to planthoppers is attributed to the feeding preference of the insects. This might be related to difference in the amount of feeding plant sap between resistant and susceptible hosts. In this aspect, this study was conducted to verify it and to develop an effective screening method for resistance to planthoppers by tracer technique. An effective P-32 labelling of rice seedlings at $2\~3$ leaf stage was dipping the roots in concentration of $0.1{\mu}Ci/ml$ solution for 48 hours. Radioactivity was significantly higher in planthopers fed on susceptible variety for 48 hours as compared to those fed on resistant variety. Radioactivity of adults was higher than that of nymphs and also higher in female than male. The results were highly correlated to that indicated by the feeding preference of the insects and therefore, considered to be valid for a screening technique.

• Korean journal of applied entomology
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• v.22 no.1 s.54
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• pp.41-44
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• 1983

In order to evaluate the technique of P-32 labelling method for screening lines of rice to whitebacked planthopper, the relationship between the amount of ingestion and feeding preference of insects were observed with the resistant and susceptible lines where characteristics were predetermined by comparing their feeding preference and antibiosis method. The feeding preference of the insects was significantly correlated with the amount of P-32 ingestion. It was more manifest in adults than nymphs of the whitebacked planthopper. The density of nymph and radioactivity of P-32 were high in the susceptible line. This suggested that deforming the ingestion amount of P-32 in the insects seemed to be useful technique for accurate screening. For this technique, the uniform labelling of P-32 on the rice seedings was prerequisite and the uniformity was increased by triming roots and leaves in the length and number.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.390-401
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• 2006

This study was conducted to understand the phytoplankton-zooplankton trophic linkage in Lake Paldang ecosystems (Paldang Dam and Kyungan Stream) from April to December 2005. Zooplankton were filtered as two size groups (microzooplankton (MICZ): 60{\sim}20\;{\mu}m$, macrozooplankton (MACZ): >$200\;{\mu}m$), and their clearance rates and C-fluxes on phytoplankton were measured. Grazing experiments were performed in the laboratory with the different zooplankton densities (0, 2, 4, 8x of ambient density, n=2). Diatoms, such as Aulacoseira and Cyclotella were dominant phytoplankton taxa at both sites. Among phytoplankton communities, total carbon biomass of phyflagellates was much higher than others at both sites. Rotifers numerically dominated zooplankton community, while cladocerans dominated carbon biomass. Both phytoplankton and zooplankton density and biomass were high in spring, but decreased markedly after summer monsoon season. plankton biomass at Kyungan Stream was significantly higher than that of Paldang Dam. Zooplankton clearance rate and amount of C-flux were relatively high in the spring and then decreased after summer at both sites. Seasonal change of C-flux was similar to that of zooplankton biomass (P<0.001, n=7). MACZ clearance rate and C-flux were higher than those of MICZ. Water residence time and physical disturbance in summer appeared to affect zooplankton grazing on phytoplankton at the study sites. Our results indicate phytoplankton were an important energy source for zooplankton in Lake Paldang ecosystem. Furthermore, C-flux of plankton food web is affected by not only biological components but also physical parameters.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.164-164
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• 2017

스마트 돈사 환경의 복지 및 생산성 향상을 위하여 정량 분석법을 기반으로 한 모돈 관리의 중요성이 증가하고 있다. 모돈은 교배, 임신, 분만, 포유, 이유를 순환적 반복하여 이루어지는데 모돈의 관리는 돈사 농장의 생산성 및 경제성과 직결된다. 모돈 관리에 필요한 환경 및 계측정보를 획득하고 이 정보로부터 모돈의 개체관리를 극대화시키고 최적의 방안을 찾고자 지속적으로 계측이 가능한 모돈의 돈사 모니터링 시스템이 필요하다. 모돈의 행동특성 계측이 가능한 시스템이 필요한 이유는 모돈의 행동 특성(섭식 및 지제불량 등)에 상응하는 대사 불량, 질병 및 발정 징후 등을 조기에 발견할 수 있기 때문이다. 돈사 내에서 정지 상태로 판별이 되는 모돈의 지제상태(기립상태, 누운 상태, 앉은 상태)와 다르게 연속적인 움직임으로부터 판별되는 모돈의 섭식상태를 분석하기 위해서는 계측 시스템과 이를 분석해주는 시스템간의 시간적 차이를 최소화 할 수 있는 실시간 신호 처리 기술이 필수적이다. 모돈의 섭식을 정량적으로 지수화하기 위한 센서의 최소 SPS(sample per second)는 600 Hz($100Hz{\times}6$개)로서 최소 6개 ADC 채널과 최소 1,200 Hz 이상으로 샘플링 할 수 있는 마이크로 컨트롤러가 필요하다. 또한 16 비트의 분해능으로 1분 동안 연속 계측을 수행할 경우 필요한 정보량은 153,600 KByte ($1,200sample/s{\times}16bit/sample{\times}8Byte/bit$)으로 실시간 처리를 수행하기에 매우 큰 정보량이라 판단할 수 있다. 수행하고자 하는 정보처리 기법에 따라 다소 상이할 수 있으나, 1분을 주기로 모돈의 섭식 분석을 수행하고자 할 경우 최도 150 MByte의 정보량을 처리하기 위한 최소의 클럭수는 단순 대입의 경우 2.5 Mhz (clock/second) ($=1clock/Byte{\times}150MByte/60seconds$) 이며 덧셈(4 clock)의 경우 10 Mhz, 곱셈(16 clock)의 경우 40 Mhz의 클럭이 필요하다. 또한 정보의 저장 및 도시를 위해 필요한 부가적인 회로(LCD, SD메모리) 구동을 위해 필요한 클럭을 고려할 경우 추가적인 클럭이 필요하다. 이를 종합적으로 고려하여 120 Mhz ($= 40Mhz{\times}3$) 이상의 클럭이 필요하다고 판단할 수 있다. 또한 센서 계측 주기의 시간 분해능을 균등하게 유지하기 위해선 계측->도시->저장의 과정을 교차적으로 수행해야 한다. 이러한 과정을 거처 최종적으로 선정한 마이크로 프로세서는 ARM Cortex-M4이며 168 MHz로 연산 수행이 가능하여 목표하고자 하는 신호처리를 수행 할 수 있다. 현장 예비 실험을 통해 기대 성능을 만족하였으며, 시간 복잡도가 높은 연산을 대비하여 최적 시분할 스케쥴링 기법에 대한 보완이 필요하다고 판단되었다.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.727-738
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• 2002

This study was conducted to investigate the effect of essential amino acid(EAA) deficient diets on short-term feeding response and the Fos expression in brain area when methionine deficiency diet fed, and thereby to know the mechanism of feed intake regulation. In all trials, experimental diets were formulated with pure amino acid mixture to level of 15% nitrogen. Rats were adapted to a 6-hr single-meal feeding per day(17:00${\sim}$21:00). Feed intake and body weight were monitored every hour after 7-day of feeding of individual EAA deficient diets in Exp. Ⅰ. In Exp. Ⅱ, Fos immuno- histochemistry was determined in various regions of brain to identify the regions that is related to suppressed feed intake following feeding methionine-deficient diet. Fos expression was examined to know the initial sensitive region in the brains of rats at 3h after feeding of the control and methionine deficient diet(-Met). Initial response to EAA deficiency diets was severely depressed in methionine deficiency diet, but the depression was low in threonine deficiency diet. However, the feed intake at 3rd day in rats was depressed in the order of His(71%), Leu(68%), Ile(66%), Thr(63%), Trp(61%), Val(55%), Phe(52%), Met(51%), Lys(44%) and Arg(24%). Fos immunoreaction in neural regions(PPC, amygdala and EPC) of pyrifrom cortex was increased in the -Met group more than in the control diet group, but those in LH, VMH and PVM were similar. Thus, based on these data, the PPC was identified as the initial response area in the -EAA diet.