• 농업과학연구
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• 제12권2호
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• pp.341-348
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• 1985

This study aims at analysis hog cycles and seasonal price patterns, and at develop the procedure for price forecasting based on the relative price ratios by farmers. Seasonal price patterns have been a persistent feature of hog markets. Some month have historically high price and other months historically low price. Hog price tend to be high in Feb, May, June, Sept, winter (Nov. to Jan.) and tend to be low in the other months. There have been four price cycles for 12 years, 1972-1984, the length of the hog price cycle has varied from 24 month to 42 months, with the irregular frequency. The increasing period of the price cycle lasted 23 months and the decreasing period of the price cycle lasted 13 months. Tables 2, 3, 4 in this study show average hog price ratios and the number of times price fall, rose for one, two, and three months ahead of each calendar month.

• 한국관개배수논문집
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• 제13권2호
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• pp.274-282
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• 2006

The objective of this study was to develop a hydrologic simulation model to predict daily streamflow from a small agricultural watershed considering irrigation return flow. The proposed IREFLOW(Irrigation REturn FLOW) model consists of hillslope runoff model, irrigation scheme drainage model, and irrigation return flow model, and simulates daily streamflow from an irrigated watershed. Two small watersheds were selected for monitoring of hydrological components and evaluating the model application. The relative error (RE) between observed and simulated daily streamflow were 2.9% and 6.4%, respectively, on two small agricultural watersheds (Baran and Gicheon) for the calibration period. The values of RE in daliy streamflow for the validation period were 6.0% for the Baran watershed, and 2.8% for the Gicheon watershed.

• 한국응용곤충학회지
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• 제44권1호
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• pp.61-65
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• 2005

왕귀뚜라미 대량 사육시 요구되는 실내 채란법 개발을 위하여 인공산란매트 선발과 알 저장조건을 조사하였다. 인공산란매트로서 수분 유지능력이 우수한 원예용 오아시스$^{\circledR}$가 천연의 매트인 흙에 비해 산란선호성이 월등히 우수하였다. 한편 인공산란매트로서 원예용 오아시스$^{\circledR}$는 흙에 비해 총산란수 및 부화율이 다소 저조하였으나 산란이 집중적으로 이루어지는 실용 산란기간(성충화 후 50일이내)의 산란수 및 부화율은 오히려 흙에 비해 우수하였다. 알의 저장조건은 산란 후 14일째, $10^{\circ}C$에 40일간 냉장한 구가 부화율 $62.1\%$로 세대단축 등을 고려할 때 단기저장으로 가장 적합한 것으로 판단되었으며, 산란 후 14일째, $7.5^{\circ}C$에 90일 냉장했을 때 부화율 $65.1\%$로 장기저장법으로 가장 적합한 것으로 나타났다.

• 농약과학회지
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• 제21권1호
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• pp.1-8
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• 2017

유기염소계 살충제 엔도설판은 2012년 국제적으로 사용이 금지되었으나 인도와 중국을 비롯한 국가들에서 여전히 사용되고 있으며 높은 잔류성과 이동성으로 인해 다양한 환경에서 검출되고 있다. 본 연구에서는 엔도설판이 토양세균의 군집구조에 미치는 영향을 16S rRNA 유전자 파이로시퀀싱 기법을 이용하여 분석하였다. 엔도설판을 100 mg/kg의 수준으로 밭토양에 처리했을 때 세균의 Operational taxonomic unit (OTU) 수와 다양성 지수가 감소했다가 서서히 증가하였으며 Proteobacteria와 Verrucomicrobia 문의 점유율은 증가하고 Chloroflexi와 Spirochaetes 문의 점유율은 감소한 것으로 나타나 엔도설판 처리가 토양세균 군집구조를 변화시키는 것을 확인하였다. 엔도설판 처리 시 Sphingomonas와 Burkholderia 속에 속하는 OTU의 점유율이 배양 초기에 높게 나타났으며 Pseudonocardia와 Opitutus 속에 속하는 OTU의 점유율은 배양 후기에 높게 나타났다. 이전 연구에서 Sphingomonas, Burkholderia, Pseudonocardia 속에 속하는 균주들이 엔도설판을 분해하였으므로 이 속에 속하는 OTU들이 토양에서 엔도설판의 분해에 단계적으로 관여했을 것으로 추정된다.

• Mycobiology
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• 제39권4호
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• pp.317-320
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• 2011

Honey production from approximately 1.6 million colonies owned by about 199,000 Korean beekeepers was almost 23,000 metric tons in 2009. Nosema causes significant losses in honey production and the virus decreases population size. We initiated a survey of honey bee colonies on the blooming period of Acacia to determine the prevalence of Nosema and virus in 2011. Most Korean beekeepers have moved from the south to north of Korea to get Acacia nectar for 2 mon. This provided a valuable opportunity to sample bees originating from diverse areas in one location. Twenty hives owned by 18 beekeepers were sampled in this year. Nosema spore counts ranged from zero to 1,710,000 spores per bee. The average number of nosema spores per bee was 580,000. Approximately 95% of the colonies were infected with Nosema, based on the presence of spores in the flowering period of Acacia. This indicates that Nosema is the predominant species affecting honeybee colonies. Also, the seven most important honeybee viruses were investigated by reverse transcription-PCR. Among them, four different viruses were detected in samples. Black queen cell virus was present in all samples. Chronic bee paralysis virus was detected in 10% of samples. Deformed wing virus was present in only 5% of the samples. Prevalence of Sacbrood virus was 15%. However, Cloudy wing virus, Israel acute paralysis virus and kashmir bee virus were not detected in any of samples.

• Animal Bioscience
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• 제34권4호
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• pp.539-545
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• 2021

Objective: Endometritis is a major disease, that causes infertility in cattle, and is usually categorized as clinical or subclinical endometritis (SCE). The nutritional condition during the dry period is important for recovery after the last stage of the lactation period, and for postpartum production and reproduction. This study aimed to clarify the relationship between nutritional and metabolic characteristics in the dry period, and the risk of postpartum SCE. Methods: Multiparous Holstein dairy cows (n = 25, raised in a tied stall) were used. Endometrial cytological analysis was performed around 30 days post-partum, with 5% to 14% polymorphonuclear (PMN) as a cut-off point to define SCE. Serum levels of glucose, non-esterified fatty acids, β-hydroxybutyric acid (BHBA), blood urea nitrogen, total cholesterol, aspartate aminotransferase, γ-glutamyl transpeptidase, calcium, phosphorus, and magnesium were measured in the cows at the dry period to evaluate energy status, protein metabolism, and mineral metabolism. Results: The incidence of SCE in the cows was 60.0% (n = 15/25) and the mean PMN% in postpartum cows diagnosed as SCE was 8.05%±2.6%. Overall, 17 and 8 samples were collected from the cows in the far-off and close-up periods, respectively. The serum concentration of BHBA in the far-off period and serum glucose concentration in the closeup period were correlated with postpartum PMN% (r = 0.62, p<0.01; r = -0.74, p<0.05, respectively). Serum levels of calcium and magnesium in the dry period were associated with the incidence of postpartum SCE (healthy vs SCE cows, p<0.05). Conclusion: Blood levels of glucose, BHBA, calcium, and magnesium in dry periods could be useful parameters for predicting the risk of postpartum SCE. The present study also suggests that management in the close-up period is essential for promoting recovery from calving fatigue.

• 한국작물학회지
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• 제46권2호
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• pp.89-94
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• 2001

Sword bean belongs to the subgenus Canavalia in the genus Canavalia. White and reddish varieties in sword bean were tested to obtain the basic information for improving the yield, quality, and cultural environments through the quantitative growth analysis. Growing plants were sampled at intervals of 10 days from 20 days after sowing. Whole plant weight increased during the period of 11-20 days after sowing in both varieties. The weight of each organ between two varieties increased similarly except leaf area. Whole plant weight changed more close to pod weight than any other characters. The leaf areas of both varieties increased from 50 days after sowing, var. white displayed S type curved line but var. reddish displayed slow S type curved line. The SGR of whole plant weight in both varieties had 3 maxima and 2 minima, 3 maxima and first minimum were shown at the same period but the second minimum was shown at different period. Both varieties showed bimodal curved line. All SGR of each organ and leaf area were shown the 2 maxima and 1 minimum in both varieties. The changes of SLA and LAR were not remarkable between two varieties but these were united together with the maximum of whole plant weight and root weight. ULWR and ULWR were shown similar in both varieties. Reddish variety was more prosperous in early growth stage than white variety because SLA, LAR and LWR were high. In surplus weight, both varieties increased rapidly during the period of 111-120 days after sowing that was applicable to the maximum SGR of pod weight. Surplus weight of var. white increased markedly during the same period comparing those of var. reddish.

• 한국농공학회논문집
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• 제53권6호
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• pp.75-84
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• 2011

The objective of this study is to evaluate the hydrologic impacts of climate and land use changes in a rural small watershed. HadCM3 (Hadley Centre Coupled Model, ver.3) A2 scenario and LARS-WG (Long Ashton Research Station - Weather Generator) were used to generate future climatic data. Future land use data were also generated by the CA-Markov (Cellular Automata-Markov) method. The Soil and Water Assessment Tool (SWAT) model was used to evaluate hydrologic impacts. The SWAT model was calibrated and validated with stream flow measured at the Baran watershed in Korea. The SWAT model simulation results agreed well with observed values during the calibration and validation periods. In this study, hydrologic impacts were analyzed according to three scenarios: future climate change (Scenario I), future land use change (Scenario II), and both future climate and land use changes (Scenario III). For Scenario I, the comparison results between a 30-year baseline period (1997~2004) and a future 30-year period (2011~2040) indicated that the total runoff, surface runoff, lateral subsurface runoff, groundwater discharge, and evapotranspiration increased as precipitation and temperature for the future 30-year period increased. The monthly variation analysis results showed that the monthly runoff for all months except September increased compared to the baseline period. For Scenario II, both the total and surface runoff increased as the built-up area, including the impervious surface, increased, while the groundwater discharge and evapotranspiration decreased. The monthly variation analysis results indicated that the total runoff increased in the summer season, when the precipitation was concentrated. In Scenario III, the results showed a similar trend to that of Scenario II. The monthly runoff for all months except October increased compared to the baseline period.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1415-1421
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• 2006

Proper nutritional management during the dry period is required to prevent metabolic disorders during the time of parturition and for potential increase milk yield during early lactation, especially under the heat of summer. The effect of prepartum diets on partitioning of nitrogen (N), calcium (Ca), phosphorus (P), magnesium (Mg) and potassium (K) during dry period and early lactation in summer was investigated. Nine cows were assigned to two groups and fed either control (group C: four cows) or high concentrate (group H: five cows) diets to meet 110% of their requirements before parturition. The proportion of concentrate in control diet was 35%, and that in the high concentrate diet was 45%. After parturition, all cows were fed the same diets ad libitum during lactation. Balance trials were conducted at 9, 8 and 7 days before parturition and at 12, 13 and 14 days after parturition. Before parturition, dry matter intake (DMI), DM and NFE digestibility in group C tended to be lower than those in group H. The retention of N (p<0.01) and P (p<0.05) in group C during the dry period was significantly lower than those in group H. The retention of Mg in group C during the dry period tended to be lower than in group H. The concentration of plasma NEFA in group C tended to be higher than in group H during dry period. The prepartum diet did not have an apparent effect on DMI and milk yield at 2 weeks after parturition and N, Ca, P, Mg and K balance after parturition.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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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.