• Title/Summary/Keyword: Natural reproduction

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Bionomics of Caloglyphus sp.(Acarina : Acaridae) (가루응애류 Caloglyphus sp.의 생태에 관한 연구)

  • Park, Ji-Doo;Kim, Jong-Kuk
    • Journal of Forest and Environmental Science
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    • v.13 no.1
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    • pp.51-56
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    • 1997
  • Developmental characteristics and reproductive ability of Caloglyphus sp. were examined under the constant temperature conditions. This mites has five stages ; egg, larva, protonymph, deutonymph and adult. All active instars preyed on larvae of pine gall midge, Thecodiplosis japonensis Uchida et Inouye. The developmental period from the egg to the adult decreased with temperature increase at a range between $15^{\circ}C$ and $30^{\circ}C$. The threshold of temperature and the thermal constant for the development from the egg to the adult were $8.2^{\circ}C$ and 122.0 day-degrees, respectively. At $25^{\circ}C$, survival rate from egg to deutonymph was estimated as 66.4%, and longevity of the adult was 12.3 days for male and 10.0 days for female. After a preoviposition period of 1 and 2 days female laid an average of 360.6 eggs each, almost all during the first half of their life time. The value of the net reproduction(Ro), the mean length of a generation(T) and the intrinsic rate of natural increase($r_m$) were calculated as 101.1, 9.3 days and 0.494 per female per day, respectively.

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A Study on Architecture and Urban Regeneration in Korea through the Perception of Body (몸의 지각론에 의한 유휴시설의 건축도시 재생에 관한 연구)

  • Hyung, Hyung-Chir;Joh, Hahn
    • Korean Institute of Interior Design Journal
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    • v.26 no.6
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    • pp.210-221
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    • 2017
  • First, we can define how our body perceives the external world and embodies its senses through the philosopher Merleau - Ponty. These philosophical orientations of Merleau-Ponty also appear to urban theorists such as Jane Jacobs, Gordon Cullen, and Juhani Pallasmaa. In other words, after the Second World War, people began to pay attention to human emotions and perceptions while opposing human rational thinking. Especially, they reject the abstract space of modernism and explore the everyday city space where the local character of the area lives. This place is a space where the collective memory of the group is shared over several generations. So, in this space, people's active perceptual system works actively. In the sense of this continuity of time, their ideas intersect with the concept of urban. Specifically, Jacobs criticizes massive development and proposes the development of a small block-based city with a commonality of old and new. In addition, we argue that urban space can be a visually interesting object through the continuous visual concept of urban theorist Cullen. In particular, he rediscovers the value of traditional urban space through visual experience between architecture and urban facilities. Finally, the architectural city theorist, Pallasmaa., criticizes the visual centrality of modern cities and thinks about the value of multidisciplinary space that can be experienced in architecture. This study examines the space of reproduction in detail on the perspective of the body philosophy and urban theorists. In other words, the play space inherits the natural city time, so when our body experiences this play space, we can actively sense and perceive the various senses. So we can invoke the active external actions of our bodies. Through the analysis of the size of the reconstruction space of the architectural city, various types of body senses and responses can be. Yoon Dongju Literary Museum, which renovated the old water tank of the city, can recognize the unfamiliar sense of body in everyday life through the traces and smells of water in the past and the restrained visuality. In addition, Seonyudo Park, which regenerates the waste water purification plant, can experience a phenomenal phenomenon through water space, old concrete and traces of steel. Finally, with the most recently played Seoul Road 7017 can experience interesting urban spaces in terms of a variety of plants, a human scale space creating movement, and a continuous visual.

RAPD Variation and Phenetic Relationships for Six Populations of Equisetum pratense in Korea (한국 내 물쇠뜨기 6개 집단의 RAPD 변이와 표현형 관계)

  • Huh, Man Kyu;Choi, Jaewon;Lee, Jangseop;Jin, Bogye;Kim, Hyun Kyung
    • Journal of Life Science
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    • v.24 no.6
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    • pp.612-617
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    • 2014
  • The phenetic relationships among six natural populations of Equisetum pratense in Korea were investigated at the population level by constructing a tree based on Random Amplified Polymorphic DNA (RAPD) markers. RAPD analysis was also conducted to estimate genetic diversity and the population structure of E. pratense. A mean of 26.7% at the six population levels indicated polymorphism. E. pratense was found to have fewer alleles per locus (1.267) and fewer effective alleles per locus (1.176). Genetic diversity (0.102) in E. pratense is lower than the average for species with similar life history traits. Total genetic diversity values (HT) varied between 0.112 (OPD-07) and 0.445 (OPD-16), for an average overall polymorphic locus of 0.141. Inter-locus variation in the within-population genetic diversity ($H_S$) was low (0.102). Asexual reproduction, small population size, and the colonization process are proposed as possible factors contributing to the observed low genetic diversity in E. pratense. On a per-locus basis, the proportion of total genetic variation due to differences among populations ($G_{ST}$) ranged from 0.129 for OPD-07 to 0.455 for OPD-09, with a mean of 0.277. This indicated that about 27.7% of the total variation was among populations. Thus, genetic variation (72.3%) resided within populations. This study contributes new information for research on the taxonomy and population genetics of E. pratense.

The Timing of Aromatase Action for Sex Differentiation in the Nile Tilapia, Oreochromis niloticus (Tilapia Oreochromis niloticus의 성분화시 Aromatase의 작용시기)

  • Kwon, Joon-Yeong;Penman, David J;Kwon, Hyuk-Chu
    • Development and Reproduction
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    • v.10 no.3
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    • pp.197-202
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    • 2006
  • Sex steroids are generally considered as natural sex inducers in fish, and aromatase (cytochrome P450 aromatase) that catalyzes androgens into estrogens in the steroidogenic pathway is also known to be involved in sex differentiation. The timing of aromatase action is, thus, of central importance in the study of fish sex differentiation. We treated sexually undifferentiated tilapia (Oreochromis niloticus) larvae with $Fadrozole^{TM}$, a non-steroidal aromatase inhibitor (AI), by immersing the fish in a solution containing AI during the sex differentiation period to narrow down the critical period of aromatase action. Fish were treated once at 11 or 13 days post fertilization (dpf), or twice at 11 and 13 dpf. The concentrations of AI at each time of the treatment were 0 mg/L (control), 50 mg/L or 100 mg/L. Survival rate was not statistically associated with AI immersion treatment (p>0.25). However, sex ratio was significantly altered by the treatment, with higher concentration and double immersion being more effective in masculinizing genetic females (p<0.05). These results suggest that aromatase action for sex differentiation in this fish species would begin at least from 11 dpf which is much earlier than previously expected, and that only 3 hours of brief immersion in AI solution is powerful enough to alter genetically programed sex.

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Effect of Temperature and Nutrition Affecting Oospore Formation of Phytophthora capsici Causing Red Pepper Fruit Rot (고추 역병균(疫病菌) (Phytophthora capsici)의 난포자(卵胞子) 형성(形成)에 미치는 온도(溫度) 및 영양(營養)의 효과(效果))

  • Chung, Bong-Koo;Kang, Me-Jong
    • The Korean Journal of Mycology
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    • v.18 no.4
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    • pp.203-208
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    • 1990
  • Sexual reproductive structure of Phytophthora capsici in vitro was round shape with thick wall and $24.4\;{\mu}m$ of diameter ranging $20-32.5\;{\mu}m$. Oogonium was $26.7\;{\mu}m$ $(21-37.5\;{\mu}m$) and $6.5-{\times}5.4m$ $(6-8{\times}5-6{\mu}m)$ for antheridium as doughnut shaped. Since mycelial contact of the paired cultures initiated right after inoculation, mycelial expansion phase was followed. Oospore morphogensis could be divided into the four phases for reproducing adult oospores. The optimum temperature for oospore reproduction was $20-24^{\circ}C$, whereas a retard trend for oospore formation was at the temperature above $25^{\circ}C$. Korean squash agar medium showed a higher oospore formation than the existing V-8 agar medium. Red pepper fruit agar medium was next. No oospore was reproduced on the red pepper leaf medium. Diurnal light with $1800{\pm}300$ and $800{\pm}300$ Lux showed rather retardation for oospore formation than dark conditions.

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Germination and Growth of Laminaria japonica (Phaeophyta) Microscopic Stages under Different Temperatures and Photon Irradiances (수온과 광량에 따른 다시마 초기 생활사의 발아와 성장)

  • KANG Rae-Seon;KOH Chul-Hwan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.4
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    • pp.438-443
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    • 1999
  • Germination and growth of Laminaria japonica microscopic stages were investigated under crossed gradients of temperatures and irradiances, and the results related to the seasonal temperature regime in the southeastern coast of Korea. Germination rates of $70\~86\%$ were observed in the temperature range of $5\~20^{\circ}C$, however, at $25^{\circ}C$ no germination of meiospores was observed. The primary factor affecting germination rates at the temperature range of $5\~20^{\circ}C$ was irradiance: germination was significantly reduced at $150 {\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$. Vegetative cell production of female gametophytes was highest at $20^{\circ}C$, but plants were not fertile at the temperature. In the temperature range of $5\~15^{\circ}C$, higher irradiance caused females to reduce cell production, but increased fertility. Cell production was also low at lower temperatures with increased fertility rates. Optimal growth temperature for microsporophytes was $10^{\circ}C$ and their growth rates were light-saturated at $70 {\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$. We have concluded that meiospores released before July could develope to the young sporophytic stage in the southeastern coast of Korea which is off the southern limit of its geographical distribution. However, limiting factor in the development of natural sporophytic population in this region would be the upper temperature limit for the survival of young sporophytes, as water temperature at this area frequently exceeds $25^{\circ}C$ during the summer period.

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A New High-Quality, Disease Resistance and High-Yielding Rehmannia glutinosa Cultivar, "Kokang" (고품질 내병 다수성 지황 고강)

  • Kim, Dong-Hwi;Park, Chung-Heon;Park, Hee-Woon;Park, Chun-Geun;Sung, Jung-Sook;Yu, Hong-Seob;Kim, Geum-Soog;Seong, Nak-Sul;Kim, Jae-Chul;Kim, Myeong-Seok;Bae, Su-Gon;Chung, Byeong-Jun
    • Korean Journal of Breeding Science
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    • v.40 no.1
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    • pp.84-87
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    • 2008
  • Kokang is a high-quality, disease resistant and high-yielding Rehmannia glutinosa cultivar developed by the medicinal crop breeding team of National Institute of Crop Science, RDA, during the period from 1997 to 2005. The reproduction of Rehmania glutinosa has been accomplished mainly by vegetative propagation with its seedlings have many variants. The cultivar was selected from seedling of Jihwang 1. The plant type of Kokang is some rising from ground. It has higher disease resistance, catalpol content and extract content compared with Jihwang 1. Regional yield trials conducted at three site from 2003 to 2005. The root yield of Kokang was 11.8ton per hectare, which was increased 13% compared with a check variety, Jihwang 1. This cultivar is adaptable to the whole of Korea except for mountain areas.

A Study on the Application of Visual Special Effects to TV Dramas; Focus on , (시각특수효과의 드라마 적용사례에 관한 연구 -<태양의 후예>,<미스터션샤인>을 중심으로-)

  • Chung, Tae-Sub
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.400-406
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    • 2019
  • This study will explore the reenactment of visual special effects used in TV dramas. The subjects of the study are images that are reproduced in visual special effects through and . Accordingly, we looked at the changes in the way TV dramas were produced according to the times, and looked at the changes in the market. Also, we looked at cases of visual special effects of Korean dramas, and looked at expressions according to the degree of completion of visual special effects. For the purpose of the analysis of the research targets, the images of reproducibility and the flow through reality were analyzed. In the case of , the period setting is realistic, but visual special effects were used to maximize the actor's safety and expression, and in the case of , the visual effects were used to maximize the aesthetic of the period background. In addition, it can be seen that the visual special effects were used for the effect of PPL on the export of images. This shows that the emphasis of reality and image montage techniques are being used to pursue hyperrealism. It is now possible to actively express and use the beauty of TV dramas rather than technical limitations. In addition, the pursuit of realism can actively express the changing times of digital age. This is an active representation of the camera's angle, lighting, and perspective that coincides with the background. The environment of video production is crucial for realistic expressions. The study examined various visual directions and applications. In TV images, we looked at reproduction, which can make a natural period of time by combining. As a follow-up study, we are going to study the changes in the new quadratic image based on the present image representation.

Establishment of propagation system for in vitro calla plants(Zantedeschia spp.) by using auxin and cytokinin hormones treatments (오옥신과 사이토키닌 호르몬 처리를 이용한 칼라 기내 식물체 대량증식체계 확립)

  • Lee, Sang Hee;Kim, Young Jin;Yang, Hwan Rae;Kim, Jong Bo
    • The Journal of the Convergence on Culture Technology
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    • v.4 no.4
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    • pp.325-329
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    • 2018
  • There are two kinds of calla belonging to the Zantedeschia spp. depending on the growing condition. Between them, various colored calla with flower shape and flower color are very popular as cut flowers. However, colored calla is very low in natural reproduction rate, and it takes a long time to obtain a flowering bulb. So it is urgent to establish a large breeding system of good varieties. In this study, various plant growth hormone treatments were carried out to improve the growth of the plants in calla. Root formation was the highest at 81.5 % in basal MS medium, and the formation of shoot and multiple shoots were the highest at 100.0 % and 36.4 % in the combined treatment of BA 2.0 mg/L and IBA 1.0 mg/L, respectively. In fresh weight, the highest growth rate was observed with 11.2 times increase in BA 2.0 mg/L single treatment. Auxin and cytokinin mixed treatment were widely used in previous studies and positive effects on the growth of calla plants will help to establish the micro-propagation system.

Comparative Analysis on the Sound Characteristics of Riffles and Pools (여울과 소의 소리특성 비교 분석)

  • Kang, Su-Jin;Kang, Joon-Gu;Kim, Jong-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.12
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    • pp.878-886
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    • 2018
  • This study quantified the sounds of riffles and pools in natural rivers and conducted a comparative analysis of the frequency and sound pressure per flow velocity. The surveyed area was Namdaecheon basin in Yangyang-gun, Gangwon-do and the sounds of a total of 23 sites were analyzed. A hydro microphone was used to measure the sound and analyze the data using an acoustic analysis program. The location was also selected at places with minimal ambient noise and the measurement points were the depth of riffles and pools. The results revealed an average difference of 0.515 m/s for flow velocity at 8 riffles and 15 pools. The difference in sound pressure occurred due to the flow velocity. In the case of sound pressure, it was measured at an average of 176.8 dB for riffles and 168.2 dB for pools, demonstrating a difference of approximately 8.6 dB. Furthermore, in the case of maximum sound pressure, riffles showed a constant range between 200 Hz and 250 Hz, while the pools exhibited maximum sound pressure at various frequencies from 200 Hz to 1,000 Hz. This revealed the ecological stream reproduction, development of preferred sound sources for aquatic life, and design of structures.