• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.475-479
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• 1994

Postweaning performance data were obtained on 401 group fed purebred Angus calves from 24 selected sires (12 high and 12 low feed conversion sires) from 1983 through 1986 at the Northwestern Branch of the Ohio Agricultural Research and Development Center. A single generation divergent selection experiment was replicated four times (1983, 1984, 1985 and 1986) to obtain an realized heritability estimate for postweaning feed conversion. The 140-d postweaning period was divided into five 28-d periods. Realized heritability estimates for feed conversion by 28-d periods fluctuated greatly and demonstrated no particular pattern. Heritability was highest for the fourth period (between d 85 and 112 of postweaning period, 0.61). Thus, beef producers could successfully select for feed conversion.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.441-461
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• 2009

Switching to organic farming practices in agricultural production reaches the end of the period it takes an average of five years. During this period, agricultural soil management to improve the investment must be sustained. Results of the survey of environment-friendly agricultural lease rates appear to approximately 54.2% lower than agricultural practices. Environmentally friendly agricultural land is leased on a long transition period of the contract cost, many buried incompleteness, uncertainty of contract fulfillment(opportunistic behavior) occurs when the transaction costs. This ultimately can hinder the spread of organic farming. Thus, the qualitative development of organic farming and land leasing in order to minimize transaction costs, should that occur. The alternative 'cooperative long-term lease contract' is a system.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.287-292
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• 1983

Incubation period of rice neck blast was investigated by injection of conidial suspension of Pyricularia oryzae into young panicles inside the flag leaf sheath at booting stage. Eleven to fifteen days were taken for symptom appearance from the date of injection. About two days were taken from conidia germination until infection occurred, the incubation period was determined as nine to thirteen days for the symptom development of neck blast in rice plants.

• The Korean Journal of Quaternary Research
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• v.3 no.1
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• pp.87-101
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• 1989

The development of the Hantan river basin can be divided into three stages. The first stage include the ancient Hantan channel system prior to the Chongokni basalt which yield dates of about 0.6 mya from the K/Ar dating method. During this period the Baekuyri formation was formed. The Baekuyri formation is widely observed under the Chongokni basalt along the current river system. The second stage is the period when stream channels stayed on the top of the basalt plateau. Aggradation and deggradation were continued by meandering and braiding channel systems until major stream channel was formed. The currently remaining deposit on the top of the basalt was formed by lacustrine and fluvial systems in this period. During this period Pleistocene hominid was present on edge of water and flood plain and left Paleolithic material. This period was begun at the time of the final basalt flow dated about 300,000 BP. The third stage is designed for the time when the Hantan river channel was dropped down to a level from which the channel could not influence the top of the basalt any more No more deposit could be formed but erosion by surface water has been continued on the top of the basalt since then. The dropping of the Hantan river channel was probably not very long after the final flow of the basalt. Because of frost action and heavy concentrated precipitation in the basin area along with blocky and clumnar joint structure of the basalt, erosional process of the basalt is believed to have been carried out within a relatively short time. The lowering of the Hantan river channel was probably completed in a cycle of major fluctuation of world cimate. Also, the redclay on the top of the basalt is believed to have been formed during a warm period around 200,000 BP, which accords with the climatic change suggested above fair1y well. The Paleolithic materials in tile deposits fell accordingly into approximately same time period.

• Korean Journal of Human Ecology
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• v.16 no.4
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• pp.699-710
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• 2007

The study purposes to explore the effects of individual characteristics and home environments of children on their bilingual language aquisition, that is, to examine whether their English language competency is different from their Korean language competency depending on those variables. Thus English or Korean language competency of children who had had early exposure in English learning were studied in terms of child's individual characteristics such as age, gender, exposure period to English, intelligence, and experiences of visiting English-speaking countries, and home environments such as parental age, educational level, income level, their perceived English competency, their perceived significance of English and Korean language, and the frequency of using English at home. 72 children who went to English kindergarten were tested with Peabody Pictures Vocabulary Test-Revised (PPVT-R) in Korean version and in English version respectively. The results show that child's intelligence and experiences of visiting English-speaking countries influence their Korean language competency. Also child's age, exposure period to English and experiences of visiting English-speaking countries influence their English language competency. Moreover their mother's educational background, father's English fluency, mothers' English fluency, and the frequency of using English at home influence child's English language competency, whereas any variables did not influence child's Korean language competency. Accordingly, child's English and Korean language competencies are related to each other.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.119-132
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• 2001

An immunoelectron microscopy employing immunogold labeling method was performed to detect tissue origin of Dl fraction (DIA) among 5 antigenic protein fractions partially purified by DEAE- anion exchange chromatography from water- soluble crude antigen (PIWA) of adult Paragonimus iloktsuenensis. Immune reactions of adult worm tissues with rabbit serum immunoglobulin immunized with crude antigen (PI-Ig) and D1 antigen (D1-Ig), as well as rat serum immunoglobulin infected with P. iloktsuenensis were observed. DlA showed strong antigenicity in the intestinal epithelium of the worms during the early infection period of 2-4 weeks after infection. The vitellaria also showed stronger antigenicity than the other tissue sites in immune reaction of tissues against all immunoglobulins from 4 to 33 weeks after vitelline development. Therefore, it is suggested that DlA was mainly originated from the intestinal epithelial tissues before the development of vitelline gland of the parasites. Immune-reactivity of two immunoglobulins (PI-Ig, Dl-Ig) was significantly different in intestinal epithelial cytoplasmic protrusions (CP) and intestinal epithelial secretory granules (SG). In the experimental group with Dl-Ig, gold particles were labeled significantly in CP than in SG when compared to the PI-Ig group. Thus, the major antigenic materials in Dl antigen having a strong antigenicity in the early infection period was considered to be originated from the intestinal epithelial tissue .

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1048-1049
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• 2006

Rapidly solidified ribbon-consolidation processing was applied for preparation of high strength bulk Mg-Zn-Gd alloys. Mg alloys have been used in automotive and aerospace industries. Rapid solidification (RS) process is suitable for the development of high strength Mg alloys, because the process realizes grain-refinement, increase in homogeneity, and so on. Recently, several nanocrystalline Mg-Zn-Y alloys with high specific tensile strength and large elongation have been developed by rapidly solidified powder metallurgy (RS P/M) process. Mg-Zn-Y RS P/M alloys are characterized by long period ordered (LPO) structure and sub-micron fine grains. The both additions of rare earth elements and zinc remarkably improved the mechanical properties of RS Mg alloys. Mg-Zn-Gd alloy also forms LPO structure in -Mg matrix coherently, therefore, it is expected that the RS Mg-Zn-Gd alloys have excellent mechanical properties. In this study, we have developed high strength RS Mg-Zn-Gd alloys with LPO structure and nanometer-scale precipitates by RS ribbon-consolidation processing. $Mg_{97}Zn_1Gd_2$ and $Mg_{95.5}Zn_{1.5}Gd_3$ and $Mg_{94}Zn_2Gd_4$ bulk alloys exhibited high tensile yield strength (470 MPa and 525 MPa and 566 MPa) and large elongation (5.5% and 2.8% and 2.4%).

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.59-65
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• 2021

Electricity contributes to the development of the economy. Therefore, forecasting electricity demand plays an important role in the development of the electricity industry in particular and the economy in general. This study aims to provide a precise model for long-term electricity demand forecast in the residential sector by using three independent variables include: Population, Electricity price, Average annual income per capita; and the dependent variable is yearly electricity consumption. Based on the support of Multiple variable regression, the proposed method established a model with variables that relate to the forecast by ignoring variables that do not affect lead to forecasting errors. The proposed forecasting model was validated using historical data from Vietnam in the period 2013 and 2020. To illustrate the application of the proposed methodology, we presents a five-year demand forecast for the residential sector in Vietnam. When demand forecasts are performed using the predicted variables, the R square value measures model fit is up to 99.6% and overall accuracy (MAPE) of around 0.92% is obtained over the period 2018-2020. The proposed model indicates the population's impact on total national electricity demand.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.51-59
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• 2017

To obtain basic data on the effects of differences cultivation periods and methods on growth and development of sweet potato tuber. We investigated growth and development of six major cultivars showing different characteristics, such as dry type(Yulmi, YM; Jinhongmi, JHM), intermediate type(Pungwonmi, PWM; Hogammi, HGM), and purple type(Sinjami, SJM; Danjami, DJM). The average tuber weight of YM and JHM was 4.1 and 8.6 g respectively, 50 days after transplant. At 80 days, the weight of YM and JHM rapidly increased to 25.2 and 26.1 g, respectively. Finally, at 120 days, the weight of YM and JHM increased to 120.7 and 79.4 g, respectively. The average tuber weight of PWM and HGM was 13 and 3.3 g, respectively, 50 days after transplant. The development pattern of PWM showed a consistent increase in tuber weight during the cultivation period, an average weight of 104.2 g at 120 days. However, the tuber development pattern of HGM was different from that of PWM. The average tuber weight of HGM rapidly increased for 100 days after transplant and then showed no increase at 120 days. In case of purple type sweet potato, the average tuber weight of SJM consistently increased during the cultivation period, whereas DJM showed rapid increase in average tuber weight at 80 days after transplant. Korean consumers prefer small, round sweet potato approximately 100g in weight. Based on the results, YM, PWM and SJM are classified as early developing cultivars that can be harvested approximately 120 days after transplant. On the other hand, JHM, HGM, and DJM are classified as late developing cultivars that can be harvested approximately 130 days after transplant.

• The Korean Journal of Malacology
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• v.25 no.2
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• pp.127-133
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• 2009

The common octopus, Octopus vulgaris is commercially important species in Korea. Korean fishing vessels have actively caught it. However, the study of this species has been poorly known. Therefore, the purpose of this study is to provide information about maturation and spawning period of this species. Samplings have been monthly collected in Tongyoung and Sacheon of Gyeongsangnam-do, using traps. A total of 748 individuals were sampled from February 2007 to January 2008. We analyzed monthly changes in maturity stages, gonadosomatic index, total weight at 50% group maturity. The octopus total weight was between 128.6 and 3381.4 g. Females were distributed between 129.8 and 3381.4 g and males between 128.6 and 2378.4 g. The spawning periods were May to June and September. The total weight at 50% group maturity was estimated to be 919.6 g.