• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.5
• /
• pp.310-315
• /
• 2000

Alfalfa (Medicago sativa L.) plants have been reported to contain water-soluble substances that are autotoxic as well as allelopathic. Laboratory experiment through a petri-dish assay with imbibed seeds was conducted to evaluate both autotoxic and allelopathic effects of alfalfa leaf extracts on the germination and early seedling growth of alfalfa, red clover, crested wheatgrass, and Russian wildrye. Alfalfa seed germination was delayed dependent on extract concentration, with no difference in final germination at 72 hours. Root growth of alfalfa was stimulated up to 14% above control at very low concentrations of both leaf and stem extracts of alfalfa and was significantly reduced at extract concentration of more than 0.5g dry tissue/L (${gL}_{-1}$). Leaf extracts were generally more autotoxic for root growth than were stem extracts. Hypocotyl growth was not affected by all the concentrations of both leaf and stem extracts. Root length of legumes was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Hypocotyl growth of two legume plants and plant height of two grasses were not influenced by extracts. Seed germination and root growth of legumes were more inhibited by aqueous extracts of alfalfa leaf than were those of grasses. This result indicates autotoxic effect of alfalfa leaf extracts seems to be greater than allelopathic effect.

• Knowledge Management Research
• /
• v.20 no.2
• /
• pp.197-216
• /
• 2019

The Korean government has been focusing on supporting technology startups to solve social and economic problems such as low growth, declining economic growth rate, rising youth unemployment rate and lack of new growth engine. Although the failure rate of young technology startups is very high, relevant researches are still scant. On the basis of previous researches, this study has identified four growth factors of technology startups: characteristics of entrepreneurs, technical superiority and originality of business items, focused marketing strategy, and follow-up government support projects. Five young technology startup cases were selected and analyzed in the cosmetics industry which were supported by the Six-month Challenge Platform project of Chungbuk Creation Economic Innovation Center. The main findings of the case study were as follows: First, product development through inhouse R&D rather than external contracted R&D was beneficial to acquiring follow-up government support projects and external investment. Second, choosing a small niche market and concentrating marketing efforts on the target market had a positive effect on firm performance. And, third, relevance of entrepreneurs' college major and technological originality of business items were confirmed to influence firm performance positively in the early stage. The results are expected to help young technology startups survive successfully and establish a foothold for growth in their early stage.

• Korean Journal of Weed Science
• /
• v.16 no.4
• /
• pp.251-258
• /
• 1996

• Journal of the Korean Home Economics Association
• /
• v.44 no.8
• /
• pp.89-99
• /
• 2006

The purpose of this study was to examine parents' selection factors and satisfaction degree in selecting an early childhood education institute according to various types of early childhood education institutes. The subjects were 650 parents of early childhood education institutes from Andong city. The result of the study can be summarized as follows. The parents' consideration degrees in the selection factors were different according to the types of early childhood education institutes. The parents' satisfaction degree on the early childhood education institutes was also different according to the types of early childhood education institutes. This result might be helpful in determining future directions for the improvement of the qualitative growth of early childhood education reflecting the demands and characteristics of parents.

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.6
• /
• pp.795-801
• /
• 2000

A total of 120 growing crossbred pigs ($Landrace{\times}Large$ $White{\times}Duroc$) with equal numbers of barrows and gilts were used in the feeding trial in a $2{\times}3$ factorial arrangement (gender by feeding regimens) to investigate the effect of phase feeding on growth performance during the 25 to 58 kg body weight growth stage, and 6 pigs (three of each sex) were used in a metabolic trial. The growing period was divided into two phases and 4 different CP diets were used to make 3 different feeding regimens (GE18-GL18; 18% CP diets for both early and later growing period, GE18-GL16; 18% CP diet for early and 16% CP diet for later growing period, GE19-GL17; 19% CP diet for early and 17% CP diet for later growing period). There were no significant differences in growth performance among treatments during the entire growing period. However, during the later growing period, feed intake of barrows was significantly higher than that of gilts (p<0.05). Average daily gain of barrows was higher than that of gilts (p>0.05). Based on the result, growth performance differences between barrows and gilts appeared to begin after 40 kg of body weight. There was no significant difference in digestibility among treatments or between sexes. During the early growing period the 18% CP diet showed better digestibility than the 19% CP diet. However, during the later growing period, the 18% and 17% CP diets exhibited similar digestibilities, although 16% CP diet showed slightly lower digestibility than 18% and 17% CP diets. During the early growing period, fecal N and P excretion of pigs fed the 19% CP were higher than that of those fed the 18% CP diet. During later growing period, fecal N and P excretion by those receiving the two phase feeding compared to single phase feeding was reduced by 10.2% and 2.0%, respectively. In the gilts, the cost reduction by two phase feeding (GE18-GL16) compared to single feeding was around 3.81%, but that of barrows was only 0.52%. The results suggested that the same nutrient levels could be applied to barrows and gilts during the growing period. Also, this study suggested the optimum protein and lysine level for early and later growing pigs to be 18% CP, 1.0% lysine and 16% CP, 0.8% lysine, respectively. Feeding two diets to growing pigs, i.e., two-phase feeding, would be more appropriate than feeding a single diet on economic and environmental considerations.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.11
• /
• pp.1614-1623
• /
• 2015

The objectives of the current experiment were to study the response of the growth performance of early finishing gilts to different net energy (NE) concentrations in diets, and to compare the NE values of diets between calculated NE values and measured NE values using French and Dutch CVB (Centraal Veevoederbureau; Central Bureau for Livestock Feeding) NE systems. In a metabolism trail, the NE concentrations in five diets used for the growth trial were determined based on digestible nutrient concentrations, digestible energy, and metabolizable energy using a replicated $5{\times}5$ Latin square design with 10 barrows (initial body weight [BW], $39.2{\pm}2.2kg$). In a growth trial, a total of 60 early finishing gilts (Landrace${\times}$Yorkshire; initial BW, $47.7{\pm}3.5kg$) were allotted to five dietary treatments of 8.0, 9.0, 10.0, 11.0, and 12.0 MJ NE/kg (calculated, as-is basis) with 12 replicate pens and one pig per pen in a 42-d feeding experiment. The NE and amino acid (AA) concentrations in all diets were calculated based on the values from NRC (2012). Ratios between standardized ileal digestible AA and NE concentrations in all diets were closely maintained. Pigs were allowed ad libitum access to feed and water. Results indicated that calculated NE concentrations in diets (i.e., five dietary treatments) were close to measured NE concentrations using French NE system in diets. The final BW was increased (linear and quadratic, p<0.05) with increasing NE concentrations in diets. Furthermore, average daily gain (ADG) was increased (linear and quadratic, p<0.01) with increasing NE concentrations in diets. There was a quadratic relationship (p<0.01) between average daily feed intake and NE concentrations in diets. Feed efficiency (G:F) was also increased (linear, p<0.01) as NE concentrations in diets were increased. The NE intake per BW gain (kcal NE/kg of BWG) was increased (linear, p<0.01) with increasing NE concentrations in diets that were predicted from both French and Dutch CVB NE systems. Linear regression indicated that predictability of daily NE intake from the BW of pigs was very low for both French ($R^2$, 0.366) and Dutch CVB ($R^2$, 0.374) NE systems. In conclusion, increasing NE concentrations in diets increase BW, ADG, G:F, and NE intake per BW gain of early finishing gilts. The BW of early finishing gilts is not a good sole variable for the prediction of daily NE intake.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.56 no.3
• /
• pp.192-198
• /
• 2011

Establishment of mechanized soybean production system without herbicide is required for organic soybean production in recent. Effects of mechanized soybean planting with partial tillage between growing rye living mulch, which was sown in April or early May, on weed suppression, soybean early growth and yield were investigated with different rye sowing dates and locations in 2007 and 2008, respectively. Effect of rye living mulch on weed suppression at 40~50 days after soybean planting was high as much as 70~90% regardless of rye sowing dates. In particular, a strong suppression effect on the occurrence and growth of Echinochloa crus-galli which occupied 60~80% of total weed biomass was observed. Rye living mulch sown on April 9, of which biomass was more than that sown on April 27, inhibited soybean early growth severely and reduced soybean grain yield in 2007. However, soybean grain yield was no t reduced despite suppression of early growth of soybean plant by living mulch sown during from late April to early May compared with conventional planting. Rye sowing before late April was not proper considering tendency of weed occurrence in spring because of unfavorable changes in weed suppression, early growth and grain yield of soybean according to amount of living mulch.

• Korean Journal of Medicinal Crop Science
• /
• v.12 no.3
• /
• pp.231-236
• /
• 2004

Crop productivity would be determined by relative capacity of source and sink. The study was carried out to measure the effects of shading and flower bud pinching on growth and yield of Atractylodes japonica Koidz. Shading treatment after transplanting was done at 100%, 65, 45 or 25% level of natural light intensity but the pinching treatment was to remove all the inflorescences formed after June 10, July 10, August 10 or none. Growth and yield at early and late stages were periodically measured. At the early stage, shading mainly influenced fresh weight rather than morphological characters. At the late stage, however, severer shading decreased numbers of stems, leaves, roots, fraction and total fresh weight. 65% shading from July 1 to September 30 after skipped the emerging and early growth stages showed nearly same growth and morphological characters but more rhizome yield per unit area than non-shading. In flower bud pinching treatment, earlier pinching increased number of roots, fraction fresh weights per plant and rhizome yield per unit area.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.2
• /
• pp.97-102
• /
• 2000

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea.

• Journal of Nutrition and Health
• /
• v.30 no.1
• /
• pp.3-11
• /
• 1997

This study was conducted to investigate the effects of protein levels and casein/whey ratios on organ growth and protein metabolism in early weaned rats. Premature rats weaned by the 17th day were fed six semipurified synthetic, isocaloric and gel diets that contained three levels (low, medium and high) and two different combinations(casein/whey ; 80 : 20 or 20 : 80) of milk protein for 8 days. On the 25th day postpartum, frest weigth and DNA, RNA and milk protein contents in brain, liver, kidney and muscle were determined to ascertain organ and cellular growth. Futher, with a view to ascertain protein metabolism and renal functions, serum total protein, $\alpha$-amino N, urea N, and creatinine and creatinine and urinary urea N, creatinine and hydroxproline were determined. Total DNA contents of brain, liver and kidney, which may represent as an index of cell numbers in those organs were significantly decreased in the rats fed diets containing low level protein regardless of casein/whey ratio. However, as fat as the rats fed high protein diets were concerned, their fresh weight, protein contents and GFR of kidney were significantly increased. Furthermore, nitrogen components, $\alpha$-amino N, urea N and creatinie in serum and urine were also increassed. Another observation was that high casein/whey ratio significantly facilitated accumulation of porteins in muscle and kidney and urinary hydorxyproline excretion, not affecting the DNA content of those organs. This study showed that low(8%) or high(32%) contents of protein had less desirable effects either on protein metabolism or on organ cellular growth in prematurely weaned rats, whereas there were no effects on general growth and bone strength.