• Asian-Australasian Journal of Animal Sciences
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• 제30권2호
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• pp.267-274
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• 2017

Objective: The objective of this study was to investigate the effect of 20-day litter weight on behavior and heart rate variability (HRV) of piglets under stress. Methods: Forty four original litters were categorized as high litter weight (HW) litters (n = 22) and low litter weight (LW) litters (n = 22) by 20-day litter weight. From each original HW litter, three males and three females were randomly selected after weaning and the 12 piglets from two original litters with similar age of days were regrouped into one new high litter weight (NHW) litter (11 NHW litters in total). The original LW litters were treated with a same program, so that there were 11 new low litter weight (NLW) litters as well. The latencies to first fighting, fighting frequencies and duration within three hours were recorded after regrouping and the lesions on body surface within 48 hours were scored. Besides, HR (heart rate, bpm, beats per minute) and activity count (ACT), time domain indexes and frequency domain indexes of the piglets were measured in an isolation trial to analyze the discrepancy in coping with stress between the original HW and LW litters. Results: The results exhibited that piglets from the HW litters launched fighting sooner and got statistically higher skin lesion score than those from the LW litters (p = 0.03 and 0.02, respectively). Regarding the HRV detection, compared with the HW litters, the LW litters exhibited a lower mean HR (p<0.05). In the isolation test, a highly significant higher ACT value was observed between the HW litters, compared to the LW litters (p<0.01). Significant differences were observed in standard deviation of R-R intervals, standard deviation of all normal to normal intervals, and most frequency-domain indicators: very low-frequency, low-frequency, and high frequency between the HW and LW litters as well. The difference in LF:HF was not significant (p = 0.779). Conclusion: This study suggests that compared with litters of low 20-day litter weights, litters with higher 20-day litter weight take more positive strategies to cope with stress and have stronger HRV regulation capacity; HW litters demonstrate better anti-stress and adaptation capacity in the case of regrouping and isolation.

• 한국임상수의학회지
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• 제30권4호
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• pp.236-240
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• 2013

A total of 170 litters (575 samples) of aborted and stillbirth fetuses submitted to the Gyeongsangbuk-Do Veterinary Service Laboratory (GVSL) between January 2006 and December 2010 from pig farms in Gyeongbuk province were studied to identify porcine abortion- and stillbirth-associated viruses such as Porcine parvovirus (PPV), Encephalomyocarditis Virus (EMCV), Japanese Encephalitis Virus (JEV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Aujeszky's Disease Virus (ADV). Virus was not detected by PCR in 36 litters, but viral antibody was detected by HI and ELISA in 93 litters. The majority of etiological viruses were PPV (67 litters, 39.4%), EMCV (50 litters, 29.4%), PRRSV (15 litters, 8.8%), and JEV (11 litters, 6.5%); ADV was not detected by either PCR or ELISA. Single infection occurred in 52 litters (30.6%), co-infection occurred in 41 litters (24.1%), and unknown cases with no detection of any of the five viruses occurred in 77 litters (45.3%).

• The Korean Journal of Ecology
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• 제16권1호
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• pp.27-37
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• 1993

During the autumn of 1991, the water soluble sulfur content in litters of platanus orientalis on the street sides in seoul, pusan, taegu, taejeon, kwangji, ulsan and ch'unch'on cities were determined. The relationship between the water soluble s content in litters of p. orientalis and the traffic was analysed. The average content of water soluble s in litters of p. orientalis in pusan, taegu, taejeon, seoul, ulsan, ch'unch'on and kwangju cities were 0.71%, 0.60%, 0.66%, 0.58%, 0.50%, 0.43%, 0.38%, respectively. The correlation was not statistically significant between the s content in litters of p. orientalis is related to the traffic of each studied area. consequently the water soluble s content in litters of p. orientalis is supposed to be an indirect indicator of air pollution.

• 아시안잔디학회지
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• 제11권1호
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• pp.33-43
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• 1997

The production and decomposition rate of litters of major forest trees in Korea, such as Quercus acutissima, Quercus mogolica Robinia pseudoacacia Pinus rigida, Pinus thunbergiana, Abies koreana,Phy'llostackys reticulata, were estimated by Olson model. The amount of mineral nutrients in litters and soil were measured, and the relationships among them were studied. The annual litter production was the most in the forest of broadleaved deciduous trees and the least in the forest of monocotyledonous trees. The decomposition rate of broadleaved deciduous litters was higher than that of coniferous litters and lower than that of R. pseudoacacia litters. The time required for the decomposition of half of the accumulated organic matter of R.pseudoacacia litter, Quercus litter, P. rigida litter, Ph. reticulata litter, P. thunbergiana litter and .4.koreana litter in the forest stands were 1.263 years, 2.290~2.365 years, 2.644 years, 4.660 years,4.750 years, 6.699 years respectively. The amounts of N in litters and the amounts of N returned to the soil in the forests of R. pseudoacacia. Quercus, Pinus were proportional to the decay rate of organic matter. Key words: Annual litter production, Decomposition rate.

• 아시안잔디학회지
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• 제9권2호
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• pp.119-129
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• 1995

Decomposition rates of glucose, starch, spinach leaves and litters in forests are calculated by equation dC dt=-kC(Co-1nC), dC- dt=$-kC^2$, and Olson's negative exponential decay model.dC dt = - kC =-kC(Co - InC) showed a very close fit to decomposition of the organic matters in cultural media by purified microorganisms and dC dt=$-kC^2$ to decomposition of the litters in forests. Key words: Organic matters, Cultural media, Glucose, Starch, Leaves, Litters.

• Asian-Australasian Journal of Animal Sciences
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• 제4권2호
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• pp.143-150
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• 1991

The data on reproductive performance of 1065 purebred Landrace, 1254 purebred Yorkshire. 553 purebred Duroc and 327 purebred Pietrain sows bred to farrow purebred litters and data from 3413 Landrace $\times$ Yorkshire, 487 Duroc $\times$ Pietrain and 3191 commericial litters were udsed in this study. The data were collected form litters farrowed form January 1986 to December 1988 in Holiday Hills Stock and Breeding Farms, San Prero, Laguna. The crossbred sows and litters were better in most traits associated with sow productivity than their contemporary purebred sows and litters. The Duroc $\times$ Pietrain crossbred litters showed 16.67% improvement in litter size at weaning, 10.11% improvement in survival rate form birth to weaning and 16.21% more pigs per sow pre year than the averages of their parental breeds. The litters from the Landrace $\times$ Yorkshire crossbred sows sired by either Duroc or Duroc $\times$ Pietrain boars had 11.01% bigger litter size at birth, 20.74% increase in litter size at weaning and 22.86% more pigs weaned per sow per year than the averages of the four parental breeds. Very little improvement in most traits evaluated were observed form the Landrace $\times$ Yorkshire crossbred litters compared with their parental breeds. Year of birth of litter had litter influence on sow productivity. However, the reproductivity performance declined when sows farrowed in June up to September. The best Months of farrowing were found to be from January to April. The breed $\times$ year, breed $\times$ month and year $\times$ month had no significant effects on all traits evaluated.

• 한국해양환경ㆍ에너지학회지
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• 제4권3호
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• pp.74-80
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• 2001

최근 연안 해역에서의 대규모 어업 활동과 경제개발로 인한 전반적인 산업화 현장의 확대, 그리고 생활 수준의 향상에 따른 여가 활동의 증가 등 다양한 요인에 의해 해저면의 침적폐기물, 폐각류, 오염 퇴적물 등 각종 오염 물질의 배출이 해양 자체의 정화 능력을 넘어서는 심각한 상태에 처해 있는 실정이다 이러한 해저면 폐기물을 그대로 방치해 두게 되면 시간이 경과함에 따라 저서 생태계의 교란을 초래하게 된다. 따라서, 해저면 폐기물에 의한 해양 생태계의 교란을 예방하고, 오염된 해양 환경을 복원하기 위해서는 해저면에 대한 수중침적 폐기물 실태조사를 실시하여 오염실태를 파악하고, 이들 관련자료를 체계적으로 관리 운영함으로서 효율적인 폐기물 수거 방안의 수립을 지원할 수 있는 체계를 갖추어야 한다. 이의 일환으로 본 연구에서는 항 내 수중침적 폐기물의 실태를 파악하기 위한 조사 방법을 확립하고, 이를 토대로 국내 연안의 주요 항만 및 어항에 대한 항 내 수중침적 폐기물 분포 현황을 조사하였다.

• Animal cells and systems
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• 제2권3호
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• pp.333-339
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• 1998

Litter decomposition is a key process in energy flow and nutrient cycling in the freshwater littoral zone, and is regulated by physicochemical properties of litters. Using a litterbag method, we compared the decomposition rates of 16 different litter types from 10 plant species of the emergent macrophytes for one year in the littoral zone of the Paltangho Reservoir, Korea. The regression analysis fitted to the various decomposition models showed that mass loss of the litters with time best fitted an asymptotic function. The litters of the emergent macrophytes were composed of two compartments, labile and refractory. The macrophytic litters showed a great variety in decomposition dynamics depending on sources of litters. The labile compartment of the initial litter mass was in a wide range between 18% and 99%, and their decomposition rates varied from 0.0037 to 0.0131 day-1. The decomposition processes of the emergent macrophytes were determined by the relative amounts of the labile and refractory compartments and by the decomposition rate of the habile one in the littoral zone.

• 한국농공학회논문집
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• 제61권5호
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• pp.101-108
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• 2019

The domestic duck industry is the sixth-largest among the livestock industries. However, 34.3% of duck houses were the duck houses arbitrarily converted from plastic greenhouses. This type of duck house was difficult to properly manage internal air temperature and humidity environment. Humidity environment inside duck houses is an important factor that directly affects the productivity and disease occurrence of the duck. Although the humidity environments of litters (bedding materials) affect directly the inside environment of duck houses, there are only few studies related to humidity environment of litters. In this study, evaporation rates from litters were evaluated according to air temperature, relative humidity, water contents of litters, and wind speed. The experimental chamber was made to measure evaporation rates from litters. Temperature and humidity controlled chamber was utilized during the conduct of the laboratory experiments. Using the measured data, a multi linear regression analysis was carried out to derive the calculation formula of evaporation rates from litters. In order to improve the accuracy of the multi linear regression model, the partial vapor pressure directly related to evaporation was also considered. Variance inflation factors of air temperature, relative humidity, partial vapor pressure, water contents of litters, and wind speed were calculated to identify multicollinearity problem. The Multiple $R^2$ and adjusted-$R^2$ of regression model were calculated at 0.76 and 0.71, respectively. Therefore, the regression models were developed in this study can be used to estimate evaporation rates from the litter of duck houses.

• The Korean Journal of Ecology
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• 제26권6호
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• pp.313-319
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• 2003

Dry weight loss and nutrient release from leaf litter for six tree species were studied using litter bag methods. The litter bags were incubated for f6 months on the forest floor in temperate deciduous forest in Mt. Cheonma, located at the middle part of Korean Peninsula. The changes in nutrient content and the rate of dry weight loss in leaf litter varied with litter types. The litter of Pinus densiflora showed the lowest rate of mass loss (k=0.33), nitrogen concentration (0.89%) and ash concentration (2.50%), while showed the highest C/N ratio (63.40). On the other hand, the litter of Acer pseudo-sieboldianum showed the fastest rate of mass loss (k=0.82), the highest nitrogen concentration (1.11%), and the lowest C/N ratio (49.40). During the decomposition, nitrogen, phosphorus and calcium in the leaf litters showed relatively slow decreasing pattern compared to other elements (carbon, potassium, magnesium, manganese and sodium), but potassium and sodium decreased at early stage of the decomposition for all leaf litters. Differences in annual decomposition rates of litter among species were consistent with the particular chemical characteristics of their leaf litters. The initial concentration of nitrogen was positively correlated with litter decomposition rate for six species, while litter decomposition rate of six species was negatively correlated with C:N ratio of initial leaf litters.