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        검색결과 70

        41.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper we introduce the Plasma Physics of Active Galactic Nuclei project, which is an ongoing experiment with Korean VLBI Network (KVN) and KVN and VERA Array (KaVA) to study multi- frequency polarimetric properties on parsec scales of active galaxies. The goal of the project is to improve our understanding of fundamental jet physics, especially evolution of the relativistic out ow coupled with the large-scale magnetic field. We selected six radio-loud AGN as our targets. So far we (i) detected resolved emissions regions at 86 and 129 GHz on VLBI scales, (ii) constructed 2D spectral index maps of the out ows, and (iii) found polarizations at 22 and 43 GHz for a few targets. Here we present spectral index distributions of 3C 120 between 22 and 43 GHz and a linear polarization map of BL Lac at 43 GHz obtained with KVN.
        3,000원
        42.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We show the results of a time series analysis of the long-term light curves of four blazars: 3C 279, 3C 345, 3C 446, and BL Lacertae. We used densely sampled light curves spanning 32 years at three frequency bands (4.8, 8, 14.5 GHz), provided by the University of Michigan Radio Astronomy Observatory monitoring program. The spectral indices of our sources are mostly at or inverted (-0:5 < α < 0), which is consistent with optically thick emission. Strong variability was seen in all light curves on various time scales. From the analyses of time lags between the light curves from different frequency bands and the evolution of the spectral indices with time, we find that we can distinguish high-peaking ares and lowpeaking ares according to the Valtaoja et al. classification. The periodograms (temporal power spectra) of the light curves are in good agreement with random-walk power-law noise without any indication of (quasi-)periodic variability. We note that random-walk noise light curves can originate from multiple shocks in jets. The fact that all our sources are in agreement with being random-walk noise emitters at radio wavelengths suggests that such behavior is a general property of blazars. We are going to generalize our approach by applying our methodology to a much larger blazar sample in the near future.
        4,000원
        44.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산업적 가치가 있는 천연 레스베라트롤은 인체에 항산화 작용, 심혈관질환 예방, 항염증 등의 효능이 있다. 레스베라트롤 생합성 벼(익산 526)를 이용하여 레스베라트롤 함량을 높이기 위해 현미의 발아온도(25°C, 30°C)와 처리일수(0, 1, 3 및 5일)의 최적조건을 구명하고자 실험한 결과는 다음과 같다. 레스베라트롤 함량은 25°C와 30°C에서 발아 5일째 각각 1.7배와 2.1배로 가장 높게 나타났으며, piceid 함량은 3.5배와 1.4배 증가하였다. 25°C 발아조건과 비교하여 30°C에서 transresveratrol은 20% 이상, piceid는 70% 이상 증가하였다. 레스베라트롤 유전자 발현량도 25°C와 30°C에서 발아 5일째 가장 높게 나타났으며, 30°C에서는 25°C와 비교하여 5.5배 증가하였다. 발아 전과 비교하여 25°C에서는 2.5배, 30°C에서 14배 증가하였다. 하지만, 익산 526의 레스베라트롤 함량 증가는 항산화 활성에 큰 영향을 미치지 않았다. 따라서, 익산 526 현미를 이용하여 레스베라트롤 함량을 증가시키기 위해서는 30°C에서 5일 동안 배양하는 것이 가장 효과적으로 향후 이를 산업적 소재로 이용 할 수 있는 기초자료로 제공한다.
        4,000원
        45.
        2014.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        담배훈연을 이용한 진딧물의 살충효과를 검정하기 위해 건조 담뱃잎을 이용하여 실험실과 온실에서 훈연시험을 실시하였다. 아크릴케이지 에서 담배를 훈연하였을 때 담배품종은 버어리종이 황색종보다 싸리수염진딧물에 대한 살충력이 높게 나타났다. 세 종의 진딧물 복숭아혹진딧 물, 목화진딧물, 싸리수염진딧물을 각각 기주를 이용하여 아크릴케이지에서 50 mg의 담뱃잎으로 훈연시험을 실시한 결과 살충율은 싸리수염진 딧물(97.2%)>목화진딧물(94.4%)>복숭아혹진딧물(63.9%) 순으로 나타났다. 복숭아혹진딧물은 기주를 가지로 했을 때 훈연에 의한 살충율이 배추를 기주로 했을 때보다 높게 나타났다. 100 m 2 규모의 온실에 황색종의 담뱃잎을 2시간 훈연 시 200 g을 이용하였을 때 싸리수염진딧물에 대 해 95.4%의 방제가를 보여주었으나 100 g을 이용하였을 때는 28.9%의 방제가를 보여주었다. 100 g의 담뱃잎은 14시간 훈연하였을 때는 2시간 훈연보다 살충효과가 2배 이상 높아졌다. 오이재배 농가 온실에서 담배훈연을 하였을 때 처리 후 목화진딧물의 방제효과는 80% 이상이었다. 온 실 환경에 따라 적절한 양과 시간을 선택해 사용한다면 담배훈연은 온실 내 발생하는 진딧물에 대한 효과적인 방제방법으로 사용할 수 있을 것이다.
        4,000원
        47.
        2014.04 구독 인증기관·개인회원 무료
        Materials are limited for pest control and chemical pesticides are prohibited in organic farming. Thus, the concept of pest control may not be effective for pest management in organic farm. As an alternative approach, landscape management is potentially effective and useful approach for preventing pathogen and insect pests in organic farm. It is needed to develop best practices utilizing functional biodiversity for pest management through landscape management. For this purpose, we investigated the effect of companion plants on species richness of insect pests and natural enemies in the field border area and in the crop plants (rice and soybean). In rice paddy fields, Lysimachiae foenum-graecum, Saururus chinensis were selected as effective companion plants on the paddy field levee for conserving Arachnidae as natural enemy and density suppression of insect pest such as Lissorphoptrus oryzophilus, Riptortus clavatus. As a result, damage rate of rice plant by insect pests was significantly lower (2.5%) and yield rate of healthy grains was significantly higher (8.7%) than control. In soybean fields, Marigold plants such as Tagetes patula, T. officinalis, increased Arthropod species richness and ratio of natural enemy group, and decreased ratio of insect pest group. As a result, yield (weight of 100 seeds) of healthy soybean was significantly increased (2.5%) than control. The 2nd infection rate from damage by R. clavatus was significantly lower in the treated plot than that in control. Thus, yield rates of healthy soybean in the control and the companion plant-treated plot were 79.0% and 84.3%, respectively, compared to conventional farming using chemical pesticides. Therefore, use of companion plants on field border was an effective practices for preventing pest insects and increasing yield in organic farming.
        48.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼멸구에 감수성이며 고품질인 ‘황금누리’와 벼멸구 저항성 유전자 Bph18을 가지고 있는 SR30071-3-7-23-6-1-1-1계통을 교배하여 전통육종법과 분자육종법을 활용하여 새로운 벼멸구 저항성 계통을 선발하여 병해충 저항성과 농업형질을 조사 수행하였다. 1. 20개체의 F1을 양성하여 F2 1,200개체를 포장에 전개하 였다. 포장에서 선발된 개체에 대해 실내미질선발을 수행하여 23개체의 F3를 공시하였으며 벼멸구 유묘검정, 도열병 밭못자 리검정, 흰잎마름병 K1 균계 접종검정을 실시한 후 F4 세대 를 거쳐 100계통을 F5 세대로 공시하였다. 2. F5 세대에서 DNA 마커 검정으로 100계통 중 Bph18은 92계통, Xa3는 96계통, Stv-bi는 98계통에서 저항성 유전자가 확인되었다. 생물검정에서는 100계통 중 벼멸구 유묘검정은 94계통이 저항성을, 흰잎마름병 K3 균계검정은 27계통 및 73 계통이 각각 저항성 및 중도저항성 반응을 보였다. 3. F5 세대 100계통 중 주요 농업적 형질이 우수한 11계통 을 생산력검정시험에 공시하였고, 보통기 보비재배에서 농업 형질이 양호하고, 수량이 높으며 병해충 저항성을 보이는 우 량한 4계통을 선발하여 이삭모양과 초형이 우수하며 출수기는 중만생종이며, 간장이 작고 수량이 높은 HR28011-1-2-3을 ‘익 산562호’로 계통명을 부여하였다. 본 실험에서 육성한 ‘익산562호’는 지역적응성 평가를 통한 품종화를 추진 중이며 벼멸구 및 기타 주요 병해충에 복합저 항성 벼품종육성을 위한 유전자원으로 활용되기를 기대한다.
        4,000원
        49.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        토마토 재배에 사용되는 농자재를 이용하여 곤충 병원성 곰팡이인 Beauveria bassiana의 병원성에 끼치는 영향을 조사하였다. Chlorothalonil 등 13종의 살균제 첨가 배지에서는 B. bassiana 균사가 전혀 생장하지 못하였고 chlorothalonil 등 12종의 살균제 첨가 배지에서균총이 형성되지 않았다. 살충제와 친환경자재를 첨가한 모든 배지에서 균사가 생장하고 포자가 형성되었지만 대부분 배지에서 무처리와 비교했을 때 유의차를 보였다. 온실가루이에 대한 살충력은 B. bassiana 단독처리일 때보다 화학살균제(polyoxin B, mandipropamid)와 친환경농자재(sulfur) 혼합시 떨어졌으며 화학살충제(pyridaben, dinotefuran)와 식물추출물 유래 친환경농자재(pyrethrum) 혼합시에는 유의차가 없었으며 온실에서 살균제인 polyoxin B의 혼합으로 온실가루이에 대한 B. bassiana의 감염력이 떨어지는 것을 확인하였다.
        4,000원
        52.
        2011.05 구독 인증기관·개인회원 무료
        Scavenger receptors (SRs) are transmembrane cell surface molecules recognized in apophotic cells, bacteria and lipopolysaccharide. With no physiological information on SRs in insects except SR-CI of Drosophila melanogaster, a putative SR gene was cloned and characterized in Spodoptera exigua. A partial S. exigua SR gene was obtained from hemocyte transcripts and exhibited high homology with type C. Its expression was confirmed in all developmental stages. Among different tissues, S. exigua SR was expressed highly in hemocytes. To confirm change in SR expression by infection, Escherichia coli was injected to fifth instar and RNA was extracted after 10 hours. SR expression in hemocytes of E. coli injected larva was not significantly different from the control but SR expression in fat body of E. coli injected larva was higher than the control. It is expected that SRs of S. exigua are related with immune responses against bacteria such as E. coli. To address its function, S. exigua SR expression was suppressed by double-stranded RNA (dsRNA).
        53.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        Purpose - Due to the lack of physical activities and the increase of sedentary behaviors such as screen time, the health condition for contemporaries has been deteriorating. This study is designed to investigate how the use of worktable or tools unfit for body and sedentary behaviors can exercise influence on muscular skeletal disease and how it has an impact on lowering work efficiency and the quality of life with the medium of the muscular skeletal disease. Research design, data, and methodology - The research has developed a questionnaire with 5 hypothesis. The questionnaires were also made by interview and E-mail. 350 copies of questionnaires were distributed and 315 questionnaire were used for the analysis as valid data responses. SPSS ver.22.0 were used and made Cronbach's and reliability test, correlation, Baron & α Kenny 3 step mediated regression analysis. Results - The research has found that living environment factors have positive effect on the occurrence of musculosketal disease. Particularly, repeated use of unfit worktable or tools has a positive effect on the muscular skeletal disorder. And sedentary lifestyle also has a positive effect on the disease. The musculoskeletal disease caused by living environment has a positive impact on lowering the work efficiency. This study has also showed that the muscular skeletal disease has mediated the relationship between the living environment factors and the decrease of work efficiency due to musculoskeletal disease. The musculoskeletal disorders can effect the decrease of the quality of life as well, for the decrease of work efficiency has a positive effect on lowering the quality of life. Conclusions - Sedentary lifestyles, the use of worktable unfit for body, and the repeated use of a tool have caused the increase of muscular-skeletal diseases, and reduction of productivity as well as the hight cost of medical treatment for our contemporaries. Understanding the cause of disease morbidity, finding ways to prevent the disease, and educating people about them would contribute not only to improvement of individual health but also to the advancement of welfare for all.
        54.
        2017.06 KCI 등재 서비스 종료(열람 제한)
        Eleven RAPD primers were assessed to analyze genetic diversity of Korean wheat varieties and to develop DNA marker for cultivar identification. The average of the number of polymorphic bands was 5.2 and PIC values showed 0.48, respectively. Ten major clades were presented by phylogenetic analysis. Three cultivars containing Uri, Hanbeak and Jonong were distinct from the others in the phylogenetic dendrogram. Seven cultivar-specific fragments were detected from 11 RAPD fingerprinting among 35 wheat cultivars and they were sequenced. Four Korean wheat cultivars, Eunpa, Jopoom, Yeonbaek and Jeokjoong, were identified newly by four markers, 84, 173, 174 and KWSM011. We convince that these new DNA markers are useful for cultivar fingerprinting and are applied to marker-assisted selection in wheat breeding program.
        55.
        2017.03 KCI 등재 서비스 종료(열람 제한)
        This study aimed to determine the optimal harvesting time for covered barley to make grain silage, in Honam region of Korea. We harvested six varieties of barley every third day from 24 to 42 days after heading (DAH). The moisture content decreased from 62.4% at 24 DAH to 24% at 42 DAH. The moisture content at 36 DAH was 44.3%; however, moisture content at 39 and 42 DAH was lower than 40%. Yield of covered barley significantly increased from 24 to 42 DAH (p < 0.05). Yield at 36 DAH (557 kg/10a) was not significantly different from that at 39 and 42 DAH (p < 0.05). With respect to the feed value of barley grain silage, the amount of crude fiber and crude ash was different by harvesting time (p < 0.05). However, the amount of crude protein, crude fat, and total digestible nutrients (TDN) from 24 and 42 DAH was not significantly different. The pH of grain silage from 24 to 42 DAH was between 3.8 and 4.2 and it was stable until 36 DAH (p < 0.05). However, the pH of grain silage at 39 and 42 DAH was 5.2 and 5.8, respectively, which was higher than the pH of silage with good fermentation quality. The lactic acid content of barley grain silage from 24 to 42 DAH decreased from 5.5% to 0.5% (p < 0.05). The amount of lactic acid at 36 DAH was higher than that at 39 and 42 DAH (p < 0.05). With respect to moisture content, yield, feed value, and fermentation, the optimal harvesting time for grain silage of covered barley was 36 DAH. This could increase the use efficiency of harvesting machine for barley and reduce the harvesting time gap between whole barley silage and grain silage in Korea. Moreover, using barley grain silage for animal feed could reduce the import of corn.
        56.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        This study investigated the effect of organic materials (Bordeaux, Loess-sulfur) and the removal of apical shoot against downy mildew disease on cucumber cultivated in greenhouse. Five kinds of Bordeaux were made by adjusting mixing ratio of lime and copper sulfate in order to elucidate the optimal combination. The 4-6type Bordeaux was selected as the most effective combination for controlling cucumber downy mildew. Loess-sulfur showed inhibitory activity against cucumber downey mildew, but it was less effective than Bordeaux. It was confirmed that apical shoot cutting could reduce the incidence of cucumber downy mildew disease by 56.3%. When apical shoots of susceptible cucumber variety were cut at different leaf stages, disease incidence by early apical shoot cutting treatment was lower than that of late apical shoot cutting treatment. However in a resistant variety, ‘Heukryungsamcheok’, disease incidences of all cucumber apical shoot cutting treatments were lower than that of non-cutting treatment, but there was no differences between apical shoot cutting treatments due to low disease incidences. In addition, when organic materials and apical shoot cutting treatment were carried out in parallel, the combined treatments of organic materials and apical shoot cutting showed low disease incidence of cucumber downy mildew compared to untreated control. The lowest disease incidence of cucumber downy mildew was recorded in the combined treatment of 4-6type Bordeaux and apical shoot cutting. This study confirmed that apical shoot cutting can reduce the disease incidence of cucumber downy mildew and the combined treatment of apical shoot cutting and organic materials showed higher suppressive effect against cucumber downy mildew
        57.
        2016.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The purpose of this study was to investigate the effect of a fresh chlorella powder on yield, quality and self-life of organic soybean tofu. After added with a fresh chlorella powder, yields, physical properties, color, shelf-life and sensory properties of the organic soybean tofu added with chlorella powder was compared to the properties of soybean tofu. The yield of soybean tofu increased with the addition of more than 1% chlorella powder. Hardness of the organic soybean tofu with chlorella significantly increased compared to that of the soybean tofu. However, Hunter’s color values of L, a, and b decreased by increases in the chlorella powder concentration. Total microbial population of the soybean tofu was higher than that of the organic soybean tofu with chlorella. However, pH of chlorella tofu decreased during storage period at 4℃. After 7 days storage at 4℃, the total microbial population decreased significantly with the addition of 2% chlorella powder. The L and a value of chlorella tofu was increased. On the other hand, the b value of chlorella tofu was decreased during storage. The results revealed that a fresh chlorella powder was a useful material to improve yield, quality and storage condition of the organic soybean tofu.
        58.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        The experiment of grape leafroller (Herpetogramma luctuosalis) was carried out at Okcheon area from 2007 to 2009 and 2015. The grape leafroller had been occurred at a campbell early’ organic vineyard in Okcheon. It’s larva was rolling the leaf of grape and ate the leaf. So the leaf of grape decreased. In organic vineyards, adult grape leafroller’ generation rate per year showed the first peak in mid-June, the second peak in early –August and the third in mid-September. The larva showed the first peak in early July and the second peak in late August-early September. The grape leaf roller had three generations per year. And it took 60.9±1.09 days from egg to adult in growth chamber (VS-91G09M-1300) which the relative humidity conditions was 60±10%, temperature 25±2℃ and photoperiod 16L:8D (The egg : 12±0 days, larvae : 22.2±0.22 days, pupa : 10.6±0.75 days and adult : 16.1±0.45 days). It was conducted to find out the effect of microbial pesticide treatments to control H. luctuosalis. The 4 microbial pesticides (Bacillus thurigiensis) were treated twice on the grape leaves in June 11 and 21 at an organic vineyard in Okcheon. On 10 days after last treatment, the control value of all microbial pesticides were more than 95%. When the dates of spraying to the grape leaves were on May 22, June 12 and July 2 each, the effects of microbial pesticide were 73.9%, 93.5% and 43.6% respectively. As a result, it was effective that Bt was sprayed to grape leaves on mid and late June for controling the H. luctuosalis in organic vineyard. And microbial pesticide Bt was thought to be useful to control the grape leafroller in organic vineyard.
        59.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        Grape cultivar “Campbell Early” account for 70% of table grape in Korea and Leaf Spot Disease caused by Pseudocercospora vitis is one of a major disease in greenhouse and field grown area during late summer season in both of organic and conventional grape farm. Leaf spot disease can cause lowing of sugar content in fruit and vine growth and very difficult to control especially in organic field. Photosynthesis ability and chemical components are compared between leaf spot disease infected leaves with degree of necrotic area. With increase of disease necrotic area, CO2 differential value, water use efficiency and CO2 assimilation and respiration ratio are decreased proportionally and on the other hand, stomatal conductance value is not affected by disease necrotic area. Chlorophyll contents are also decreased by 50% in heavily infected leaves and imply decrease of chlorophyll contents is a major source of photosynthesis ability decline. With increase of disease necrotic area in leaves, total nitrogen and phosphate contents are decreased and on the other side, total carbon, potassium, calcium and magnesium contents are increased. From this research, we can infer that not only chemical control program is important in control of leaf spot disease but also fertilizing program is significant especially in organic agronomical control of fungal disease in grape cultivar “Campbell Early”.
        60.
        2015.07 서비스 종료(열람 제한)
        High temperature is one of major environmental stress. Some of molecular markers related heat stress or tolerance have been reported by many researchers. Heat tolerance managing is difficult through the phenotypic selection, so marker assistant selection (MAS) using molecular markers like as RAPD, SSR ect. was tried to selection of useful traits for heat tolerance. Fourteen SSR markers reported by previous research were selected for this research. These markers were linked to important traits including grain filling duration, HIS (Heat susceptibility index) grain filling duration. In this study, we tried to evaluate 14 SSR markers for MAS using 31 useful wheat resources including 24 crossing line from Turkey and six Korean wheat cultivars using 14 SSR markers. The average of the number of alleles and PIC values in this study were 6.14 and 0.63, respectively. Two major clades and six sub clades were grouped by phylogenetic tree using UPGMA program. Six Korean wheat cultivars were distinct from other Turkey resources in the phylogenetic dendrogram. From the results, we expected that these markers were able to adapt to screening wheat genotyping for heat tolerance.
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