• The Korean Journal of Nuclear Medicine
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• v.2 no.1
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• pp.49-52
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• 1968

The influence of estradiol on the radioactive calcium metabolism in blood, bone and young of lactating rats has been studied. Estrogen, in an amount estimated to equal that secreted in late pregnancy, was injected daily into lactating rats for 4 days along with $^{45}Ca$. On the 5th day, radioactivity of blood serum, bone, and young was compared to a similar group of lactating rats not treated with estrogen. Average gain in weight of the litters of the 2 groups was similar. However, radioactivity in serum and bones of treated with estradiol was significantly higher than in the controls. The radioactivity in litters of the 2 groups was similar. Estrogen plays a role in the retention of calcium in the animal body.

• Asian Journal of Turfgrass Science
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• v.10 no.4
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• pp.297-304
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• 1996

The investigation was performed to reveal the removal rate of metal constituents of litters in a Phragmites communis Miseanthus sacchariflorus, Typha angastata and Seirpas tabernaemontani grasslands in the lake Paldangho. The removal rates of metal constituents are determined by the mathematical models. The removal rates and time required to decay up to a percentage of each metal constituent were calculated using these model. The removal rates of Cu, Fe and Zn were 0.61, 0.58 and 0.79 in Phragmites communis 0.39, 0.47 and 0.68 in Miseanthus saccharflorus; 0.26, 0.09 and 0.23 in Typha angustata: 0.56, 0.27 and 0.67 in Seirpus tabernaemontani respectively. The periods required to reach half time to the stedy state of the removal and accumulation for Cu, Fe and Zn were 1,13,1.19 and 0.79 years in Phragmites communis; 1.79, 1.49 and 1.02 years in Miscanthus sacchariflorus; 2.70, 7.43 and 2.96 years in Typha angustata ; 1.23, 2.58 and 1.04 years in Scirqus tabernaemontani, re-spectively. Key words: Phragmites communis, Miscanthus sacchariflorus, Typha angustata and Scirpus tabernaemontani, lake Paldangho, Removal rate, Cupper, Iron, Zinc.

• The Korean Journal of Ecology
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• v.9 no.4
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• pp.231-241
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• 1986

The annual decomposition of cellulose and hemicellulose by microorganism and distribution of soil microbial flora were investigated in the humus horizon of a Pinus rigida stand in Mt. Kwanak. The cellulase activity was the lowest, 142$\mu$g glucose/g/hr from Dec. 1985 to Mar. 1986 and the highest, 760~1, 072$\mu$g glucose/g/hr in Jul. and Aug. 1985. The xylanase activity was 47% higher than the cellulase activity and was the lowest, 211~275$\mu$g xylose /g/hr from Feb. to Mar. 1986 and the highest as 799~1, 322$\mu$g xylose/g/hr from Jun. to Aug. 1986. The vertical distribution of the enzyme activity was decreased with the order of F, H, L, and A1 in both enzymes and the activities were exponentially decreased below L horizon, which suggests that most decomposition be done in F and H horizons with lots of organic matters. The SEM study slowed that the main decomposers of litters were fungi and initial attack into litters was also made by them. The enzyme activities of soil had strong correlations with the temperature and the precipitation. The correlation coefficients were 0.813 and 0.886 in the cellulase, and 0.673 and 0.626 in the xylanase for the temperature and the precipitation, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.220-226
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• 2005

This study evaluated the composition and distribution of marine litters on the sea-bed of the East China Sea. Surveys have been conducted by a benthic trawlnet of Dong-baek training ship of Yosu national university during the cruise of 2002-2004. Distribution density showed high value in C5 (north-western area of Jeju Island) with $110.3kg/km^2$ and those of annual mean were about $31-43kg/km^2$. Fishing gears such as nets, pots, octopus jars and etc. were about 42-72% of debris collected in the East China Sea. Composition ratio of rubber, vinyl. metal, plastic, glass, wood, cloth and etc. were within 25% except C5. Rope and drum showed strong fluctuations with 0-30% according to the trawling sites. Some vinyls and nets made in Korea, China and Japan were much collected. It is estimated that fishing gears were discarded to the sea by fishing operation, deliberately or not. An comprehensive program including continuous research, monitoring for marine litters in the Korean sea were necessary.

• 한국생태학회:학술대회논문집
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• 2002.08a
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• pp.79-82
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• 2002

Main attackers on pine seeds on the forest floor were investigated in Korea. Damage on pine cones begins in early stage of cone formation, especially by squirrel and Korean squirrel. The above animals left Kayak-like hulls of seed on rocks and fallen tree trunk. Field mice also left the same shape of Kayak-like hulls. But birds including doves and peasants left large shreds with longitudinal cracks or seed cup trace. Most of seeds on the leaf litters as well as under the fallen leaf were consumed by fold mice and birds. Especially fold mice found the seeds under fallen leaves and consumed all of them.

• Asian Journal of Turfgrass Science
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• v.11 no.2
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• pp.125-137
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• 1997

Five dictyostelid cellular slime molds were isolated from the littoral grassland ecoystems of the lake Paldangho, safeguard of waterworks, Kyounggi-do, South Korea. They were Poiysphoadylium violceum, Dictyosielium aureo-stipes var. aureo-stipes D crassicaule, D macrocephalum and D gigauteum. P. violaceum was dominant species. It live on the low nutrient and barren soils as the littoral zone destabilized in surface soils, litters and chemicals by inundation an rain precipitation. Key words: Cellular slime mold, Littoral grassland ecosystem.

• The Korean Journal of Ecology
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• v.25 no.4
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• pp.213-216
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• 2002

Main attackers on pine seeds on the forest floor were investigated in Korea. Damage on pine cones begins in early stage of cone formation, especially by squirrel and Korean squirrel. The above animals left Kayak-like hulls of seed on rocks and fallen tree trunk. Field mice also left the same shape of Kayak-like hulls. But birds including doves and peasants left large shreds with longitudinal cracks or seed cup trace. Most of seeds on the leaf litters as well as under the fallen leaf were consumed by field mice and birds. Especially field mice found the seeds under fallen leaves and consumed all of them.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1617-1622
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• 2005

The activity of brush border enzymes (sucrase, lactase and maltase) in the piglet small intestine was evaluated as well as piglet performance during the weaning period in the present study. There were two treatment groups: Piglets of six litters were fed dry feed plus milk replacer (Group M) and of six litters fed dry pelleted feed (Group C). One piglet from each litter was sacrificed on day 3 before weaning, and day 3, 10 and 17 postweaning, respectively. Providing milk replacer caused an increased piglet live weight at weaning (p<0.001) and until termination of the experiment (p<0.001). A slightly higher (p<0.16) level of protein was measured in the jejunum of group M piglets as compared with group C piglets. Before weaning the activity of lactase was high in the jejunum of group C piglets. The activity of lactase in the jejunum was lowered in the jejunum of group C piglets and in distal jejunum of group M piglets during the postweaning period as compared with pre-weaning period (p<0.05). Lowered activity of lactase in the distal jejunum of piglets was found at day 10 and 17 postweaning, respectively. No treatment differences were found in the activity of lactase in the piglet jejunum. No treatment differences were seen in the activity of maltase and sucrase in the piglet jejunum also. However, weaning caused a higher activity of sucrase in the distal jejunum of group M piglets as compared with pre-weaning period. In conclusion, providing milk replacer to piglets caused an improved growth performance. Feeding milk replacer did not influence the activity of lactase, maltase and sucrase in the jejunum of piglets. Weaning resulted in a markedly lowered activity of lactase, while no dramatic changes in the activity of maltase took place during the period around weaning.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1747-1751
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• 2001

An experiment was conducted to determine the effects of dietary oligosaccharides on performance and intestinal microbial populations of piglets. Ten litters of piglets were assigned to five groups randomly, with two litters per group. The control group was fed with corn-soybean basal diet. Oligosaccharides was added to the basal diet at the level of 0.05%, 0.1%, 0.2% and 0.35% respectively to form four experimental diets. The experiment was conducted with two periods. The first period (suckling period) was from 7 to 28 days of age and the second period (weanling period) was from 28 to 56 days of age. Fresh fecal samples were collected at 21 days of age and assayed for Escherichia coli concentration, pH and moisture content. Three pigs per group were slaughtered at 42 days of age and cecum, colon, and rectum content samples were collected and assayed immediately for Escherichia coli and Bifidobacterium concentration, pH and moisture content. The results showed that dietary oligosacchrides decreased fecal Escherichia coli population and pH significantly (p 0.05), but did not affect performance and fecal moisture content during suckling period. 0.1% oligosaccharides for weanling pigs increased growth and improved feed conversion ratio together with a reduction of diarrhea (p 0.05), but 0.35% oligosaccharides did not affect growth performance. 0.1% and 0.2% oligosaccharides for weanling pigs had a suppression to Escherichia coli colonization in rectum and an enrichment to Bifidobacterium in colon (p 0.05). Oligosaccharides decreased significantly (p<0.05) rectum moisture content, but did not affect cecum, colon and rectum pH.

• Animal Bioscience
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• v.34 no.12
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• pp.1903-1911
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• 2021

Objective: The objective of this study was to estimate the genetic parameters and various litter trait trends of Danish pigs in South Vietnam, including the number born alive (NBA), number weaned (NW), and litter weight at the 21st day (LW21). Methods: Records of 936 Yorkshire sows with 3361 litters and 973 Landrace sows with 3161 litters were used to estimate the variance components, genetic parameters, and trends of NBA, NW, and LW21. The restricted maximum likelihood method was applied using VCE6 software to obtain the variance components and genetic parameters. Thereafter, the best linear unbiased prediction procedure with an animal model was applied using PEST software to estimate the breeding values of the studied traits. Results: The heritability estimates were low, ranging from 0.12 to 0.21 for NBA, 0.03 to 0.04 for NW, and from 0.11 to 0.13 for LW21. The genetic correlation between the NBA and NW was relatively strong in both breeds, at 0.77 and 0.60 for Yorkshire and Landrace, respectively. Similarly, the genetic correlation between the NW and LW21 was considerably stronger in Landrace pigs (0.71) than in Yorkshire pigs (0.48). The estimates of annual genetic progress were 0.0431, 0.0233, and 0.0461 for NBA, NW, and LW21 in Landrace pigs and 0434, 0.0202, and 0.0667 for NBA, NW, and LW21 in Yorkshire pigs, respectively. Conclusion: The positive genetic trends estimated for the additive genetic values of the selected traits indicated that the current breeding system has achieved favorable results.