• Title/Summary/Keyword: Long-tail

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A Ultrastructural Study on the Axoneme Formation in the Spermatozoa of the Edible Giant Snail, Achatina fulica (식용 왕달팽이 (Achatina fulica) 정자의 축사형성 (Axoneme formation)에 관한 미세구조)

  • Chang, Nam-Sub
    • Applied Microscopy
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    • v.28 no.4
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    • pp.513-525
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    • 1998
  • The spermatogenetic process in the edible giant snail is similar to those in the other snails, except for the axoneme formation process. In this study, the axoneme formation process in the giant snail was mainly examined by means of electron microscopy. The tail portion of a spermatozoon is about $160{\mu}m$ long, and extends straight to the rear, surrounded by two large and long mitochondria in spiral forms. A number of glycogen particles $(40\sim70nm)$ are found in the swollen matrix of the mitochodria. The axoneme which composes the tail of a spermatozoon is surrounded by $7\sim10$ lamella-form fibrous sheaths of about $0.2{\mu}m$ in thickness. Most of the mature spermatozoa are found to be clustered into a group of $5\sim7$ ea in syncytial bridges formed by cytoplasmic processes. Sertoli cells contain glycogen particles, endoplasmic reticulum, a lot of mitochondria, and lipids in their cytoplasm. They protrude their filiform pseudopodia and phagocytize abnormal spermatids or spermaozoa.

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Depth Control of a Hybrid Underwater Glider in Parallel with Control of Horizontal Tail Wing (수평 꼬리 날개의 제어를 병행하는 하이브리드 수중 글라이더의 깊이 제어)

  • Joo, Moon Gab
    • IEMEK Journal of Embedded Systems and Applications
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    • v.14 no.1
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    • pp.25-31
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    • 2019
  • An underwater glider is a type of autonomous unmanned vehicle and it advances using a vertical zig-zag glide. For this purpose, the position of an internal battery is regulated to control its attitude, and the amount of water in a buoyancy bag is regulated to control the depth. Underwater glider is suitable for a long-distance mission for a long time, because the required energy is much smaller than the conventional autonomous unmanned vehicle using propeller propulsion system. In this paper, control of horizontal tail wing is newly added to the conventional battery position and buoyancy control. The performance of the proposed controller is shown through Matlab simulation.

A Study on the Experimental design of Tail stock for High Precision Processing in Lathe (선삭에서 고정도 가공을 위한 심압대의 실험적 설계에 관한 연구)

  • 김경석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.361-366
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    • 2000
  • To make high precision cutting of long materials or a piston for the engines, it must be necessary to keep the stability of spindle and tail stock in CNC lathe. If a object is clamped at the ends, the thermal expansion and cutting generated in cutting process appear as the deflection of in cuttings objects. Especially, of a piston ring, piston ovality and piston profile, the influences are very serious. In order to solve the problems most of piston cutting are worked in simply support. However, the problems exist, yet.

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Genetic Variability and Relationships of Native Japanese Chickens Assessed by Microsatellite DNA Profiling - Focusing on the Breeds Established in Kochi Prefecture, Japan -

  • Osman, S.A.-M.;Sekino, M.;Nishibori, M.;Yamamoto, Y.;Tsudzuki, M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.6
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    • pp.755-761
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    • 2005
  • Blood samples were collected from eight native Japanese breeds of chickens (Miyadi-dori, Ohiki, Onaga-dori, Shoukoku, Tosa-Jidori, Tosa-Kukin, Toutenkou and Uzurao) and two foreign breeds of chickens (White Leghorn and Rhode Island Red) to examine the genetic variability and relationships among the breeds by using a microsatellite DNA technique. Except for the Shoukoku breed, the other Japanese chicken breeds all originate from Kochi Prefecture. Ohiki, Onaga-dori, Tosa-Jidori, Toutenkou and Uzurao are fancy fowl, and Miyadi-dori and Tosa-Kukin are utility fowl. Among the fancy fowl, Ohiki, Onaga-dori, and Toutenkou males have thick and long feathers in the saddle and tail. Genetic variabilities of the 20 microsatellites examined, varied depending on the breed: the mean number of alleles per locus ranged from 2.05 (Miyadi-dori) to 3.90 (Rhode Island Red); proportion of polymorphic loci ranged from 0.75 (Miyadi-dori) to 1.00 (Rhode Island Red, Shoukoku and Uzurao); and mean expected heterozygosity ranged from 0.330 (Miyadi-dori) to 0.607 (Rhode Island Red). Unique microsatellite alleles were detected in each breed. Using the neighbour-joining method, phylogenetic trees were constructed based on the genetic distances of D$_{A}$ and D$_{ST}$. Among the breeds originating from Kochi Prefecture, fancy and utility breeds belonged to different clusters. Among the fancy breeds, those having thick and long feathers in the tail and saddle showed a close genetic relationship to the Shoukoku breed, which also has thick and long feathers in the tail and saddle.

Low Carbon.Green Growth Paradigm for Fisheries Sector (수산부문 저탄소.녹색성장 패러다임)

  • Park, Seong-Kwae;Kwon, Suk-Jae
    • Ocean and Polar Research
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    • v.31 no.1
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    • pp.97-110
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    • 2009
  • Two of the most important topics of the 21st century are ensuring harmony between man and his environment and the emerging long-tail economy in which niche markets are becoming increasingly more important. Since the Industrial Revolution in 17th century, human beings have increasingly exploited the world's natural capital, such as the natural environment and its ecosystems. Now the world is facing limits to sustainable economic growth because of limits to this natural capital. Thus, most countries are beginning to adopt a new development paradigm, the so-called"Green Development Paradigm" which pursues environmental conservation in parallel with economic growth. Recently, the Korean government announced an ambitious national policy of Low Carbon & Green Growth for the next six decades. This is an important step that transforms the existing national policy into a new future-oriented one. The fisheries sector in particular has great potential for making a substantial contribution to this national policy initiative. For example, the ocean itself with its sea plants and phytoplankton has an enormous capacity for fixing carbon, and its vast areas of tidal flats have a tremendous potential for cleaning up pollutants from both the sea and the land. Furthermore, the fishing industry has great potential for the development of fuel-saving biodegradable technologies, and a long-tail economy based on digital technologies can do much to promote the production and consumption of green goods and services derived from the oceans and the fisheries. In order for this potential to be realized, the fisheries authority needs to develop a new green-growth strategy that is practical and widely supported by fishing communities and the markets, taking into account the need for greenhouse gas reduction, conservation of the ocean environment and ecosystems, an improved system for seafood safety, the establishment of strengthened MCS (monitoring control surveillance) system, and the development of coastal ecotourism. In addition, fisheries green policies need to be implemented through a well-organized system of government aids, regulations and compensation, and spontaneous (voluntary) orders in fishing communities should be promoted to encourage far more responsible fisheries.

Demand Concentration in the Korean Digital Online Movie Market (디지털 온라인 영화시장의 수요 집중화 경향)

  • Choi, Sung-Hee
    • The Journal of the Korea Contents Association
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    • v.21 no.8
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    • pp.69-78
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    • 2021
  • With technological development including digitization, movie demand and supply in digital online movie market are increasing. This study aims to explore demand concentration of the digital online movie market, which is characterized by product variety compared to cinemas. Major findings of the empirical analysis on the TV VOD data during the recent seven years(2013 ~ 2019) are as follows. First, the analysis on 1,137 titles reveals that movie demand of theatrical market is more concentrated than that of TV VOD. Second, absolute long tail index of TV VOD, measured by the download number of indie & artistic movies(niche product), is increasing as more such movies are released in the market. However, both relative long tail index, measured by the share of indie & artistic movie demand, and top-ranked movies' share do not show consistent increase or decrease trend. Third, regression analysis exhibits that the relationship between demand concentration and market size is insignificant for TV VOD market. This study might have usefulness in that it provides empirical evidence for the nature of the Korean digital online movie market.

A Study on the Fine Structure of Clonorchis sinensis, a Liver Fluke V. The Mature Spermatozoa (간흡충의 미세구조에 관한 연구 V. 정자의 미세구조)

  • 정계환;임한종
    • Parasites, Hosts and Diseases
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    • v.22 no.1
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    • pp.30-36
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    • 1984
  • An ultrastructural study on the mature spermatoBoa oi Cloptorchis sineitsis was carried out. For this study, the liver cukes were collected from the livers of rabbits and rats artificially infected with the metacercariae obtained from the fresh water fish, Pseudorasbora parve. Six-month old worms were used. The collected liver fiukes were washed with 0.85% saline solution and then immediately moved to cold 2% glutaraldehyde buffered with 0.1M Millonig's phosphate buffier (pH 7.4) . The materials were dissected into appropriate pieces in the fixative about 30 minutes after beginning of the fixation. Two hours later the materials containing the seminal receptacle were rinsed several times with the buffier and were secondarily fixed with cold, bugeyed 1% osmium tetroxide(OsO4) for 2 hours. The fully mixed tissue blocks Ivere dehydrated in a series of graded concentrations of acetone and were embedded in Epon 812 mixture. Thin sections obtained from LKB-5 ultramicrotome were stained with uranyl acetate and Reynold's lead citrate. Observations of the sections were carried out with JEM-100CX II electron microscope, In general, the mature sperm was long thread-like form with a sickle-shaped head. According to the longitudinal sectioned view of the sperm tail, the nucleus seemed to be spirally coiled and run a little far along the tail. The acrosome was not observed. The cytoplasm of the tail was biflagellated as usual in trematodes. Unlike other platyhelminth spermatozoa, the sperm tail of Clenorchis sinensis showed the ${\ulcorner}9+2{\lrcorner}$ in the microtubular arrangement. The mitochondria with poorly developed cristae were observed throughout the middle piece. The middle piece of the tail showed dull ladder or triangular shapes with the two flagella at the bottom. But, the principal piece of the tail was slightly flattened cylindrical shape with two aagella within the cytoplasm. The end piece was uniflagellated. It was not clearly identised whether the end piece was subdivided into two by aagellum or the lengths of the two aagella were different. The glycogen granules were rich in the cytoplasm throughout the lenght of the spermatozoa. These granules might be the energy source for the movement of the spermatosoa.

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Garbage Collection Synchronization Technique for Improving Tail Latency of Cloud Databases (클라우드 데이터베이스에서의 꼬리응답시간 감소를 위한 가비지 컬렉션 동기화 기법)

  • Han, Seungwook;Hahn, Sangwook Shane;Kim, Jihong
    • Journal of KIISE
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    • v.44 no.8
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    • pp.767-773
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    • 2017
  • In a distributed system environment, such as a cloud database, the tail latency needs to be kept short to ensure uniform quality of service. In this paper, through experiments on a Cassandra database, we show that long tail latency is caused by a lack of memory space because the database cannot receive any request until free space is reclaimed by writing the buffered data to the storage device. We observed that, since the performance of the storage device determines the amount of time required for writing the buffered data, the performance degradation of Solid State Drive (SSD) due to garbage collection results in a longer tail latency. We propose a garbage collection synchronization technique, called SyncGC, that simultaneously performs garbage collection in the java virtual machine and in the garbage collection in SSD concurrently, thus hiding garbage collection overheads in the SSD. Our evaluations on real SSDs show that SyncGC reduces the tail latency of $99.9^{th}$ and, $99.9^{th}-percentile$ by 31% and 36%, respectively.

Performance differences of Rhode Island Red, Bashang Long-tail Chicken, and their reciprocal crossbreds under natural cold stress

  • Xie, Shanshan;Yang, Xukai;Gao, Yahui;Jiao, Wenjie;Li, Xinghua;Li, Yajie;Ning, Zhonghua
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.10
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    • pp.1507-1514
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    • 2017
  • Objective: The Bashang Long-tail chicken (BS), an indigenous Chinese breed, is considered cold tolerant. We selected BS, the Rhode Island Red (RIR), and their reciprocal crossbreds for the present study. The objectives were: i) to validate whether BS is cold tolerant and whether egg production and cold tolerance of crossbreds could be improved; and ii) to determine the physiological characteristics that underlie cold tolerance and favorable egg production performance in cold environments. Methods: A total of 916 chickens were reared in warm and natural cold environments (daily mean ambient temperature varied from $7.4^{\circ}C$ to $26.5^{\circ}C$ in the warm environment and from $-17.5^{\circ}C$ to $27.0^{\circ}C$ in the cold environment). To investigate their adaptability to the cold environment, the egg production performance and body weight were monitored and compared between breeds and environments. The cloacal temperature and serum biochemical parameters were monitored to reveal the physiological characteristics underlie cold tolerance and favorable egg production performance in the cold environment. Results: The warm environment experiment showed that RIR had the highest egg production performance, and that the reciprocal crossbreds had a higher egg production performance than BS. While in the cold environment RIR had the lowest egg production performance, and the reciprocal crossbreds had a higher egg production performance than BS. In the cold environment BS and reciprocal crossbreds had higher triiodothyronine, tetraiodothyronine levels than RIR. At 35 and 39 wk of age, when the ambient temperature was extremely low (varied from $-20^{\circ}C$ to $0^{\circ}C$), serum glucose, follicle-stimulating hormone, luteinizing hormone, estradiol of BS and crossbreds were higher than RIR. Conclusion: Bashang Long-tail chicken has a favorable cold tolerance ability. Crossbreeding with RIR and BS is an effective way to develop cold tolerant chickens with improved egg production performance.

Genetic Composition of Korean Native Chicken Populations - National Scale Molecular Genetic Evaluation Based on Microsatellite Markers (초위성체 표지로 본 한국 재래닭 집단의 분자유전학적 구성)

  • Lee, Poong-Yeon;Yeon, Seong-Heum;Kim, Jae-Hwan;Ko, Yeoung-Gyu;Son, Jun-Kyu;Lee, Hee-Hoon;Cho, Chang-Yeon
    • Korean Journal of Poultry Science
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    • v.38 no.2
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    • pp.81-87
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    • 2011
  • The study was conducted to select and optimize microsatellite (MS) markers for evaluate Korean Native Chicken (KNC) breeds in order to provide standard for the classification and breed definition of the indigenous breeds. The study also aimed to characterize and classify each KNC populations for inventory and management of avian genetic resources. A total of 462 chickens from 11 populations of chicken breeds including eight KNC breeds and three commercial chicken breeds were analyzed with 19 MS markers. KNC breeds, especially Long-Tail Chicken breeds, formed separate cluster from those commercial chicken breeds. Genetic distances between KNC populations (0.11~0.18) were relatively shorter. Genetic uniformity of KNC (except KNCR breed) (0.86~0.88) were higher than that of commercial breeds (except Cornish) (0.95~0.97). On the other hand, genetic uniformity of KNC Long Tail (KNCLT) were relatively higher (0.91~0.97). The result can be used to evaluate and manage animal genetic resources at national scale.