• Title/Summary/Keyword: Natural reproduction

Search Result 412, Processing Time 0.028 seconds

Development of Road Safety Estimation Method using Driving Simulator and Eye Camera (차량시뮬레이터 및 아이카메라를 이용한 도로안전성 평가기법 개발)

  • Doh, Tcheol-Woong;Kim, Won-Keun
    • International Journal of Highway Engineering
    • /
    • v.7 no.4 s.26
    • /
    • pp.185-202
    • /
    • 2005
  • In this research, to get over restrictions of a field expreiment, we modeled a planning road through the 3D Virtual Reality and achieved data about dynamic response related to sector fluctuation and about driver's visual behavior on testers' driving the Driving Simulator Car with Eye Camera. We made constant efforts to reduce the non-reality and side effect of Driving Simulator on maximizing the accord between motion reproduction and virtual reality based on data Driving Simulator's graphic module achieved by dynamic analysis module. Moreover, we achieved data of driver's natural visual behavior using Eye Camera(FaceLAB) that is able to make an expriment without such attaching equipments such as a helmet and lense. In this paper, to evaluate the level of road's safety, we grasp the meaning of the fluctuation of safety that drivers feel according to change of road geometric structure with methods of Driving Simulator and Eye Camera and investigate the relationship between road geometric structure and safety level. Through this process, we suggest the method to evaluate the road making drivers comfortable and pleasant from planning schemes.

  • PDF

Studies on the Glochidial Encystment in Host Fish during the development of Anodonta arcaeformis flavotincta (작은대칭이, Anodonta arcaeformis flavotincta의 유생 발생 중 숙주어류내에서 글로키디움 유생의 피낭 형성과정에 관한 연구)

  • 박갑만
    • Development and Reproduction
    • /
    • v.2 no.1
    • /
    • pp.81-87
    • /
    • 1998
  • A scanning electron microscopic study on the glochidial encystment and excystment during the development of Anodonta arcaeformis flavotincta on Carassius auratus, a common natural host fish, was carried out. The glochidia were attached to the fins, buccal cavity and gills of the host fish within 30 minutes. In this study, the fins of host fish infected with the glochidia were examined in a time series. The attachment rates of the glochidia on the pectoral fins, caudal fin and pelvic fins of the host fish were 30%, 22%, and 17%, respectively. The glochidia which attached to the fish became encysted within 27 hrs. The process of encystment progressed slowly. Ti took 24 to 27 hours in the formation of the primary cyst, and after 5 to 6 days, the larvae was covered completely with the epithelial cels of the host tissues. The process of detachment of juvenile clam was observed on the 8th day after host infection. Most of the juvenile clams have sloughed from the cyst of the host within 15 days. No significant size difference was observed in the glochidia and the juvenile which were found before attachment and after detachment from the cyst of the host fish.

  • PDF

Egg Development and Morphology of Larva and Juvenile of the Oryzias latipes

  • Lee, Sung-Hun;Kim, Chun-Cheol;Koh, Soo-Jin;Shin, Lim-Soo;Cho, Jae-Kwon;Han, Kyeong-Ho
    • Development and Reproduction
    • /
    • v.18 no.3
    • /
    • pp.173-178
    • /
    • 2014
  • In order to monitor the developmental features of embryos, larvae, and juveniles of Oryzias latipes (Temminck and Schlegel), Oryzias latipes was caught in river of Shinduck-dong, Yeosu-si, Jeollanam-do, on May 2011, and experiments were carried out in Ichthyology laboratory at Chonnam National University. The blastodisc step was the first level for natural spawning. The optic vesicle, Kupffer's vesicle, myotome began to appear 75 hours 57 minutes later. After blastodisc development, the pectoral fins were made at 143 hours 37 minutes and the tail was separated started at the same time. Hatching was observed at 167 hours 27 minutes after blastodisc. The total length of the hatched larvae was 4.95~5.10 mm (mean, 5.01 mm), the mouth and anus were opened. Larvae used yolk completely after 3 days after hatching. The total length larvae was 5.45~5.56 mm (mean, 5.52 mm) after 8 days after hatching, and appeared the stems for tail. The stems pectoral, anal fin were showed after 14 days and the stems dorsal, ventral fin were appeared after 19 days. For 35 days after hatching, the total length of larvae 13.95~15.30 mm (mean, 14.64 mm), and at this time, fins and body were transferred like the adult Oryzias latipes.

Analysis for the Duplication of Achievement Standards between Science and Other Subjects in the 2009 Revised National Curriculum (2009개정 교육과정에서 과학과와 타교과의 성취기준 중복성에 대한 분석)

  • Park, Jae-Keun
    • Journal of Science Education
    • /
    • v.38 no.2
    • /
    • pp.231-243
    • /
    • 2014
  • The purpose of this study was to compare the duplication problem of achievement standards between science and other subjects in the 2009 Revised National Curriculum and to search for solutions and implications for this problem. From the results of this study, we found that the achievement standards of practical arts, social studies, physical education and ethics were overlapped with science's ones. The duplication of content elements for 'our body and health', 'living things and environment', 'biodiversity' and 'natural disaster' categories was not high, that is, their achievement standards were relatively well-differentiated and reflected the intrinsic characteristic of each subject under common topics. But, in case of 'reproduction and development' and 'world of technology' categories, the problem of duplications was serious. In order to cope with this problem, we need to consider solutions such as merging or integrating the achievement standards of related subjects. The relevant experts should conduct in-depth discussion and negotiation, and develop achievement standards more consistent with the identity of each subject.

  • PDF

Cloning of Transgenic Rabbit Embryos Expressing Green Fluorescent Protein Gene by nuclear Transplantation (Green Fluorescent Protein 발현 토끼 수정란의 핵이식에 의한 복제)

  • Kang, T. Y.;Yin, X. J.;Rho, G. J.;Lee, H.;Chae, Y. J.;Lee, H. J
    • Journal of Embryo Transfer
    • /
    • v.15 no.2
    • /
    • pp.167-173
    • /
    • 2000
  • The principal objective of this study was to clone transgenic embryos in order to improve the efficiency of transgenic animal production by the combination of microinjection and nuclear transplantation techniques. Mature female New Zealand White rabbits were superovulated by eCG and hCG treatments, fllowed by natural mating. Zygotes were collected from the oviducts at 18∼22 h after hCG injection by flushing with D-PBS containing 5% fetal calf serum(FCS). Two to three picoliters of green fluorescent protein(GFP) gene wa microinjected into male pronucleus. The foreign gene-injected zygotes were cultured in TCM-199 or RD medium containing 10% FCS with a monolayer of rabbit oviductal epithelial cells in a 5% CO2 incubator. The morulae expressing GFP gene were selected and their blastomeres were separated for the use of nuclear donor. Following nuclear transplantation of fluorescence-positive morula stage blastomeres, 13 (21.3%) out of 61 fused oocytes developed to blastocyst stage and all of the cloned blastocysts expressed GFP. The results indicate that the screening of transgene in rabbit embryos by GFP detection could be a promisible method for the preselection of transgenic embryos. Also the cloning of preselected transgenic embryos by nuclear transplantatin could be efficiently applied to the multiple production of transgenic animals.

  • PDF

Impacts of Aquatic and Riparian Environmental Factors on Eurasian Otter (Lutra lutra) Presence Characteristics in the Nakdong River Basin (낙동강 권역의 하천 수면공간 및 수변환경이 수달의 출현에 미치는 영향분석)

  • Shin, Geehoon;Rho, Paikho
    • Journal of Environmental Science International
    • /
    • v.26 no.12
    • /
    • pp.1341-1353
    • /
    • 2017
  • This study aimed to identify the aquatic and riparian factors associated with the presence/absence of the Eurasian otter in the Nakdong river basin, where the species is relatively more abundant than other otter species. Environmental factors and presence records were collected. Geographical Information System technology and chi-square test were used to compare environmental gradients in aquatic and riparian factors between presence and absence sites. Aquatic habitat attributes were evaluated with natural riverside sandbars and channel crossing artificial structures, the ratio of channel width to alluvial plain width, riverbed substrate, and flow diversity. Riverbank characteristics, bank materials, man-made embankment types, and land use/land cover of inland and riverside areas were selected as riparian habitat attributes. Compared to the aquatic attributes, riparian attributes were highly significant when assessing otter presence and absence sites, suggesting that conservation of suitable riparian areas to provide maternity and resting areas for otter species is essential in the Nakdong river basin. None of the aquatic attributes examined were statistically significant when evaluating otter presence or absence. These results indicate that the presence of suitable riparian area for resting and reproduction habitats is more critical to the presence of Eurasian otter than food availability in aquatic areas. To inform implementation of effective conservation actions, broad-scale factors, such as watershed attributes, would be needed to further assess habitat conditions of the Eurasian otter.

Cyclic variations of gonad development of an air-breathing fish, Channa striata in the lentic and lotic environments

  • Al Mahmud, Nasim;Rahman, Hassan Md. Hafizur;Mostakim, Golam Mohammod;Khan, Mohd. Golam Quader;Shahjahan, Md.;Lucky, Nahid Sultana;Islam, M. Sadiqul
    • Fisheries and Aquatic Sciences
    • /
    • v.19 no.1
    • /
    • pp.5.1-5.7
    • /
    • 2016
  • The study was conducted to know the cyclic changes in gonadal maturation and to investigate the developmental stages of oocytes and testicular germ cells of an air-breathing fish, Channa striata. Fish were sampled monthly from lentic and lotic environments of three geographical locations of Bangladesh from December to November and the histological analysis of their gonad was done to evaluate the objectives. The highest mean GSI was $5.95{\pm}0.20$ for female in July and $0.14{\pm}0.01$ for male also in July showing that the gonadal development reached its peak during this month. The highest mean oocyte diameter was $1257.50{\pm}24.17{\mu}m$ observed in July implying that the oocyte reached maturity in this month. Histological study of ovary revealed the evidence of early yolk granule stage and late yolk granule stage from April to July. In case of male four stages of spermatogenesis were distinguished and spermatozoa were highly abundant in June and July. So the monthly pooled values of GSI and the analysis of gonadal histology indicated that the peak breeding season of C. striata occurred in July in the lentic and lotic environments. Samples collected from lentic and lotic habitats are suggestive of no difference in the development of the gonad. The results of the present study will be useful for selective breeding programme, conservation and sustainable fishery management of C. striata in its natural habitat.

Control of $Ca^{2+}$- Influx by $Ca^{2+}$/Calmodulin Dependent Protein Kinase II in the Activation of Mouse Eggs

  • Yoon, Sook-Young;Kang, Da-Won;Bae, In-Ha
    • Development and Reproduction
    • /
    • v.15 no.1
    • /
    • pp.31-39
    • /
    • 2011
  • Change in intracellular $Ca^{2+}$-concentration ($[Ca^{2+}]_i$) is an essential event for egg activation and further development. $Ca^{2+}$ ion is originated from intracellular $Ca^{2+}$-store via inositol 1,4,5-triphosphate receptor and/or $Ca^{2+}$ influx via $Ca^{2+}$ channel. This study was performed to investigate whether changes in $Ca^{2+}$/calmodulin dependent protein kinase II (CaM KII) activity affect $Ca^{2+}$ influx during artificial egg activation with ethanol using $Ca^{2+}$ monitoring system and whole-cell patch clamp technique. Under $Ca^{2+}$ ion-omitted condition, $Ca^{2+}$-oscillation was stopped within 30 min post microinjection of porcine sperm factor, and ethanol-induced $Ca^{2+}$ increase was reduced. To investigate the role of CaM KII known as an integrator of $Ca^{2+}$- oscillation during mammalian egg fertilization, CaM KII activity was tested with a specific inhibitor KN-93. In the eggs treated with KN-93, ethanol failed to induce egg activation. In addition, KN-93 inhibited inward $Ca^{2+}$ current ($I_{Ca}$) in a time-dependent manner in whole-cell configuration. Immunostaining data showed that the voltage-dependent $Ca^{2+}$ channels were distributed along the plasma membrane of mouse egg and 2-cell embryo. From these results, we suggest that $Ca^{2+}$ influx during fertilization might be controlled by CaM KII activity.

Ecology and Early Life History of Endangered Freshwater Fish, Pseudobagrus brevicorpus (Pisces: Bagridae) (꼬치동자개(Pseudobagrus brevicorpus)의 생태와 초기 생활사)

  • Kang, Eon-Jong;Yang, Hyun;Lee, Heung-Heon;Cho, Yong-Cheol;Kim, Eung-Oh;Lim, Sang-Gu;Bang, In-Chul
    • Korean Journal of Environmental Biology
    • /
    • v.25 no.4
    • /
    • pp.378-384
    • /
    • 2007
  • Some of ecological factors and the early life history of endangered freshwater fish, Pseusobagrus brevicorpus, were investigated to proliferate artificially and to restore the population by release seedlings. The density of population in restricted area by small scale dam was 1.25 ind. $m^{-2}$, and the low capacity for reproduction having 200$\sim$250 eggs ind$^{-1}$. were thought to be a reason of this endangered situation. From the result of induction of natural spawning in aquarium after hormone injection it was considered that the spawning substrate would be aquatic plants with slender branches. The hatching was observed after 50 hrs after fertilization and the larvae showed aggressive behavior. Yolk was almost absorbed 3 days after hatching, and the larvae shaped tad-pole grew up to fry after 30 days. We discussed on the strategies for conservation of this species according to those results from investigation on ecology and early life history.

Fundamental Studies on Human Sciences by Facial Form Analysis - Based on Unit Fluid Model of Essence, Qi energy, Emotion, Blood - (안면형상연구의 인간과학적 기초 연구 - 정기신혈(精氣神血)의 유체역학적(流體力學的) 해석을 중심으로 -)

  • Kim, Jong-Won;Lee, In-Seon;Kim, Kyu-Kon;Lee, Yong-Tae;Kim, Kyung-Chul;Eom, Hyun-Sup;Chi, Gyoo-Yong
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.22 no.5
    • /
    • pp.1057-1061
    • /
    • 2008
  • For the purpose of investigating the reasonable logics contained in physiognomy of east and old western medicine. hypothetical researches based on hydromechanics theory were performed concerning facial types of form and pathologic features, especially 4 types of Dr. Jisan-Essence, Qi energy. Emotional Activity and Blood(EQAB). In order to infer the functional relation between facial type forming and EQAB factors, EQAB were supposed as fluid grounded on their continual flowing or periodical change and pressure effect from its congestion. and a premise that there's a linear corresponding relationship between the appearance of organ and its physical conditions of its inner vessels is formed too. Through this work, the unit fluid model(UFM) of Essence can be assumed as circle shape formed by the high viscosity and surface tension, the UFM model of Qi energy as quadrangular shape by the scattering features to outer four directions, and the UFM of emotional activity as inverted triangular shape by the flippant and uprising features, and the UFM of blood as ellipsoid triangle by the heavy and descending features in spite of circulation. The shapes made from each UFM are reproduced in the process of human development and manifest respective facial shape through the self-reproduction method like fractal theory in the last. Conclusively. it is said that the facial form analysis method like EQAB type theory can be the useful methodology to understand the human pathological and physiological features in view of hydromechanics.