• The Korean Journal of Ecology
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• 제17권4호
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• pp.523-531
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• 1994

Optimal conditions for the seed germination and growth of Hedyotis diffusa were studied. As photoperiod was increased from 12 hr to 24hr, the germination rate of Hedyotis diffusa was gradually increased. The photoperiod and temperature inflenced on the fermination synergistically. After the growth of 20 weeks under the natural condition (June~Oct.), the length of H. diffusa was $38.9{\pm}4.2cm$ (15.5~52.5cm), and total dry weight per $3.3m^2$ was $316.7{\pm}10.3g$. It is considered that H. diffusa could be cultivated in a part of inland. The anticancer effect of H. diffusa extract was examined. F-344 rats aged 6 weeks were divided into 3 groups and were given an I.P. of diethylnitrosamine at 200mg/kg body weight as a promoter, initially. And in two weeks after the beginnign of the experiment, group 1 was supplied iwth feed containing 0.02% 2-AAG as a promoter for 6 weeks. Group 2 was supplied with feed containing extracts of H.diffusa (0.02%) for two weeks. Group3 was supplied with only basal diet. All rats were sacrificed for partial hepatectomu, and the antipromoting effect was examined by the number 문 area per $cm^2$ of foci in river. In group 1, the number of hyperplastic nodule was $18.5{\pm}7.7$, but in group2, it was drastically reduced to $10.3{\pm}1.8$ rather thn those of group1. The total area of nodules $(mm^2)$ /whole liver $(cm^2)$ of group 1 and group2 were $19.2{\pm}7.7$ and $5.0{\pm}3.2$, respectively. These results indicate that extract of H.diffusa act as an anticancer agent at statistically significant level (p<0.001).

• Journal of Ecology and Environment
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• 제38권3호
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• pp.353-360
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• 2015

A survey of weed occurrence was conducted to identify problematic weed species in a horticultural crop field to get basic information for effective weed control. Surveys of weed species occurring in horticultural crop fields (garlic, onion, red pepper and Chinese cabbage) were conducted in Chungnam province of Korea from April to October in 2014. A total of 516 sites of the 17 regions were identified as having 114 weed species belonging to 32 families. The most dominant weed species in the horticultural crop fields were Chenopodium album var. centrorubrum (8.83%), followed by Digitaria ciliaris (5.71%), Conyza canadensis (5.46%) and Capsella bursa-pastoris (4.67%). Specifically, as a result of this study, the occurrence of 35 species of exotic weeds, such as Chenopodium album and Taraxacum officinale, were confirmed. Almost 68% of the investigation sites was determined under dominance value 1 (range of cover < 10; numerous individuals) by Braun-Branquet cover-abundance scale, indicating a proper weed control in horticultural crop field. As a result of scientific and technological advances, an improved cultivation method is changing the weed occurrence in agricultural land. Additional research needs to be undertaken for the development of weed control methods through such periodic monitoring of occurrence of weeds.

• Journal of Ecology and Environment
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• 제31권4호
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• pp.269-276
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• 2008

In order to understand the role of seed banks for restoration, seed banks in abandoned rice fields in the Gwangneung National Arboretum, central Korea were investigated using the seedling emergence method. The study sites represented three stages: an initial stage dominated by forbs such as Persicaria thunbergii and Juncus effuses var. decipiens, a middle stage dominated by Salix, and a late stage dominated by Quercus aliena and Prunus padus (in nearby riparian forest chosen as a reference stand). DCA ordination arranged the stands according to the number of years since abandonment. CCA ordination identified the dominant environmental variables correlated most closely with Axes 1 and 2 as $Mg^{2+}$ (intraset correlation was 0.827) and $K^+$ (intraset correlation was -0.677), respectively. Species richness and diversity decreased from the initial stage (H'=2.61) to the middle (H'=1.79) and late (H'=0.75) stages. A total of 49 species $(/m^2)$ and 18,620 seedlings $(/m^2)$ emerged out of the seed bank samples. The DCA ordination and similarity analysis detected a large discrepancy between the composition of the actual vegetation and the seed bank. We conclude that the contribution of seed bank to restoration is low. However, seed bank may help the recovery of forbs after disturbance. Some of our results are consistent with the tolerance model of succession whereas others follow the trajectory of the facilitation model. More research on succession will be required to understand the underlying mechanisms.

• ALGAE
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• 제31권1호
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• pp.17-31
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• 2016

To explore the feeding ecology of the newly described heterotrophic dinoflagellate Aduncodinium glandula in the family Pfiesteriaceae, its feeding behavior and prey species were investigated. Additionally, the growth and ingestion rates of A. glandula on the mixotrophic dinoflagellates Heterocapsa triquetra and Akashiwo sanguinea, its optimal and suboptimal prey, respectively were measured. A. glandula fed on prey through a peduncle after anchoring to the prey using a tow filament. A. glandula ate all algal prey and perch blood cells tested and had the most diverse prey species in the family Pfiesteriaceae. Unlike for other pfiesteriacean species, H. triquetra and A. sanguinea support the positive growth of A. glandula. However, the cryptophytes Rhodomonas salina and Teleaulax sp. and the phototrophic dinoflagellate Amphidinium carterae did not support the positive growth of A. glandula. Thus, A. glandula may have a unique kind of prey and its optimal prey differs from that of the other pfiesteriacean dinoflagellates. With increasing mean prey concentration, the growth rates of A. glandula on H. triquetra and A. sanguinea increased rapidly and then slowed or became saturated. The maximum growth rates when feeding on H. triquetra and A. sanguinea were 1.004 and 0.567 d⁻¹, respectively. Further, the maximum ingestion rates of A. glandula on H. triquetra and A. sanguinea were 0.75 and 1.38 ng C predator⁻¹ d⁻¹, respectively. There is no other pfiesteriacean species having H. triquetra and A. sanguinea as optimal and suboptimal prey. Thus, A. glandula may be abundant during blooms dominated by these species not preferred by the other pfiesteriacean dinoflagellates.

• 대한화학회지
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• 제46권6호
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• pp.550-560
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• 2002

이 연구는 일반화학을 수강하는 대학생들이 지닌 ''문제 및 문제해결''에 대한 사고를 학습 맥락의 관점에서 살펴보았다. 서울에 소재한 한 대학의 일반화학을 수강하는 9명의 연구 참여자들을 대상으로 하여, 개별 면담, 수업관찰, 학생들이 작성한 수필 등을 통하여 자료를 수집하였다. 수집된 자료는 순환적인 성분 비교 분석틀을 사용하여 분석되었다. 연구 결과에 의하면, 일반화학을 수강하는 학생들이 문제 및 문제해결에 대한 사고는 학교 과학 성취도와 관련지어 인식하는 것, 학습 구성과 관련하여 인식하는 것, 문제 유형과 관련하여 인식하는것 등의 여섯 가지 특징으로 나타났다. 그러한 특징은 대부분의 연구 참여자에게 공통적으로 나타났으며, 화학 학습의 개념생태 내에 중요하게 자리잡고 잇는 것으로 파악되었다. 이와 관련해서 화학 및 과학 교수, 학습에 대한 시사점을 논의 하였다.

• 한국의류학회지
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• 제29권9_10호
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• pp.1349-1358
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• 2005

Generally apparel products were recognized as an incongruent product type which direct search was needed for. But nowadays apparel products were ranked as a second product type next to electronics in sale amount of internet shopping mall. Therefore more detailed study on which attributes of fashion products are more successful and suitable in internet shopping mall is necessary. This study was executed to analyze common attributes of successful apparel in internet shopping mall on the basis of real sale data, and then to help internet apparel marketer plan marketing strategies more efficiently. Common attributes of successful apparel products in internet shopping-mall in terms of product, price and promotion attributes were identified. 240 products which were loaded in bestseller section of internet shopping-mall for 8 weeks from November to December, 2004 were analyzed. The results are as follows. First, products ratio for women ($76.7\%$) were higher than for men($18.3\%$). And the amount of each apparel product types purchased by consumers were ranked in the order of leather/fur coat, woven coat, inner wear, jacket, T-shirts, pants, training wear, suit, knit wear etc. and basic style dominated in $74.2\%$. General brands ($69.2\%$) that had price competitiveness were preferred to famous designer brand, national brand and PB brand. Preferred level of price was ten thousand to fifty thousand won. For promotion skill, in order of just one product, product adding promotion product and package set were preferred. Regular price, less than $50\%$ off and more than $50\%$ off price showed no difference in preference. Product planning strategy for internet apparel marketer was followed on the basis of these results.

• 생태와환경
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• 제49권3호
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• pp.176-186
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• 2016

For several decades, lactic acid bacterium (Lactobacillus graminis: LAB) has been generally recognized as safe. To develop the pan-environmental bio-control agent, algicidal activity of the live LAB cell and its culture filtrate (CF) was examined against Microcystis aeruginosa. LAB cells perfectly lysed M. aeruginosa within 3 days, while the CF had a less effect than the live cells, approximately 78% inhibition of algal growth during a same culture period. The concentration of microcystin in alone culture of M. aeruginosa was $7.1{\mu}gL^{-1}$, but gradually increased and leach $158.5{\mu}gL^{-1}$ on 10 days. However, LAB cells clearly decreased the microcystin by $10.3{\mu}gL^{-1}$ in the same period, approximately 93.5%. CF of LAB showed a strong algicidal activity over 75% between pH 2-7, 91.3% by the treatment of proteinase K, 87.8% by below 3 kDa in particle size, and 75.3% by heat treatment, respectively. Of five solvents, fractions of CF passed through solvents diethyl ether and ethyl acetate showed an obvious algicidal activity in the algal-lawn test. Among 5 fractions purified by silica-gel TLC plate, two spots showed a most strong removal activity on M. aeruginosa. Another analysis of GC indicate that CF contained six representative fatty acids. Even though most of these substance have been known as an anti-algal substance against M. aeruginosa, oleic acid is the most effective. These results suggested that the culture filtrate or specific substances, like a fatty acids, in comparison with live L. graminis can be a successful and eco-friendly agent to control Microcystis bloom.

• 환경생물
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• 제25권3호
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• pp.249-259
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• 2007

식장산의 현존식생과 입지환경을 고려한 식생조사구 총 114개소를 설치하여 식생구조를 분석한 결과 산지림유형, 계곡림유형, 인공림유형의 3개 유형으로 분류되었고, 총 23개의 군락으로 구분되었다. 식생 분포는 사면상부와 능선부에 신갈나무군락이, 남사면에는 소나무군락과 굴참나무군락이 각각 분포하였으며, 신갈나무군락의 점유 면적이 34,213ha로 전체 면적의 31.9%로 가장 넓은 영역을 차지하고 있었고 계곡림은 좁은 면적에 매우 많은 군락들로 구성되어 있었다. 계곡림 유형에서는 졸참나무, 갈참나무, 물푸레나무, 고로쇠나무, 까치박달, 산딸나무 등의 수종들의 층위별 중요치가 높았다. 종다양도는 인공림유형의 물오리나무군락이 0.2191로서 가장 낮았고, 계곡림 유형의 종다양도지수가 약 0.9로서 가장 높았다.

• 생태와환경
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• 제38권2호통권112호
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• pp.188-195
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• 2005

2000년부터 2004년까지 5년간 횡성호 일대의 어류군집 동태를 조사한 결과는 다음과 같다. 조사기간동안 출현한 어류는 총 10과 39종이었으며 이 중 한국고유종은 Rhodeus pseudosericeus 등을 포함하여 총 17종 (43.59%) 이었다. 우점종은 Acheilognathus lanceolatus (20.10%), Zacco platypus (15.94%), Z. temmincki (6.92%), Carassius cuvieri (6.33%), A. rhombeus (6.18%), Pungtungia herzi (5.13%), Pseudorasbora parva (4.93) 등이었다. 조사시기별 출현종을 근거로 생활형에 따른 어류군집은 담수가 되면서 점차 저서성 어종의 수가 감소하였고 부유성 어종이 증가하는 것으로 나타났다. 또한 조사시기별 유사도 분석을 한 결과 각 조사시기는 비가중치 평균연결법 (UPGMA)에 의해 3개의 그룹으로 나누어졌다. 한편 다른 인공호와 본 조사의 어류상을 근거로 유사도 분석을　한 결과 수계에 따라 2개의 그룹으로 나누어졌으며 같은 수계 내에서 다시 3개의 그룹으로 나누어졌다. 이 중 횡성호 어류군집의 현재 상태는 북한강 중류의 춘천-청평호와 유사한 것으로 나타났다.

• 한국지역지리학회지
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• 제16권1호
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• pp.16-33
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• 2010

본 연구는 한국의 고문헌인 "신증동국여지승람"과 "택리지"의 내용 중에 기후와 식생 관련 기록을 가려 뽑아 이 기록들이 갖는 기후 및 식생, 즉 자연 지리 또는 생태 연구 자료적 의의를 고찰한 것이다. 연구 대상인 두 종의 지리지에는 각각 14~15세기와 18세기에 살았던 사람들이 당시의 생활 터전에 대한 자연 환경과 생태에 대해 보였던 관심과 내용이 다수 들어있다. 이 기록들을 활용하면 당시의 기후 환경, 각 지방별 기후 특성, 산지 기후는 물론이고 한반도의 남해안 및 남부 중부 북부 지방의 식생 경관을 파악할 수 있을 뿐 아니라 복원도 가능할 것으로 믿어진다. 때문에 한국의 고문헌을 활용한 자연 지리 및 생태 경관 복원에 대한 연구 방법론에 대한 구체적인 논의를 시작할 필요가 있다.