• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.135-144
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• 1980

The reproductive cycle and the breeding season of the freshwater clam, Anodonta (Sinanodonta) woodiana (Lea) have been investigated by histological examination of the gonadal development under photomicroscopy. The materials were monthly collected from the Nakdong River for one year from September 1979 to August 1980. Sexuality of Anodonta (Sinanodonta) woodiana is dioecious, and the species are ovoviviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of small ovarian sacs, The epithelium of ovarian sac has a function of the germinal epithelium. Oogonia actively proliferate along the germinal epithelium of the ovarian sac, in which young oocytes are growing. The testis is composed of a number of seminiferous tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between the growing oocytes and spermatocytes in the early development stages. With the further development of the ovary and testis these tissues and cells gradually disappear. Then the undifferentiated mesenchymal tissue and granular cells are considered to be related to the growing of the oocytes and spermatocytes. The gonads had function year-round the individuals which have various developmental stages of gonads appearing all the time. Spawning continued year-round except for the period of high temperature of water, during August and September. The peak spawning seasons appeared twice a year between January and March, and between June and July in 1980. Individuals which have trochophore larvae in the marsupium of the adult appeared year-round except September 1579 and August 1980. The rate of individuals which have glochidia in the marsupium was 72.7 percent in May 1980 which was the highest brooding fate.

• Journal of the Economic Geographical Society of Korea
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• v.20 no.4
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• pp.453-485
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• 2017

One of the oldest chestnuts in economic geography is this: Cultural and creative industries strongly gather in large cities and this geographic concentration of economic activities leads to regional development. Of course, depending on the circumstances, such a proposition still holds good. But, under the current paradigm shift to knowledge-based economy, it may be open to question. This study aims to investigate financing and knowledge accumulation in the film industry through an alternative framework for explaining their spatial distributions, "formation mechanism of economic space." From the fact that their production organizations are formed on a project basis, project-based financing structure in the investment stage and knowledge accumulation process in the production stage form both axes of it. Film industry as the most mature industry among the cultural and creative industries does not always concentrate in a certain place (industrial agglomeration) or show metropolis-oriented preference. This allows us to reconsider our long brooding theory.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.90-97
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• 2008

The aim of this research was to detect and observe delivering generation effects from $F_0$ generation exposed to 4-nonylphenol 4NP) to $F_1$ generation on Tigriopus japonicus. The nauplius survival rate of $F_1$ from $F_0$ exposed to low 4NP concentration was significantly lower than other concentrations. Among the developmental process, copepodite first emergence day (CE) and adult male first emergence day (ME) on $F_1$ were accelerated relatively high concentration conditions. The sex ratio of $F_1$ was different between control group and treatment groups for 1, 10 and $30{\mu}g\;L^{-1}$ 4NP. The fecundity of $F_1$ was not significantly affected (except, $0.1{\mu}g\;L^{-1}$ 4NP). When 4NP concentrations were increased, first brooding day (FB) of F 1 was generally delayed. The length, width, and biomass of $F_1$ adult female were smaller than control group. In addition, the width and biomass of adult male were narrower or smaller than control group.

• Korean Journal of Poultry Science
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• v.13 no.2
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• pp.179-186
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• 1986

A total of 749 Korean native Ogol fowl[Natural Monument No, 265] and 45,340 Ogol eggs were used to investigate the various performances of Ogol, I. e., fertility, hatchability, viability, body weight, and rate of egg production. The studying periods was from May, 1985 to Sept., 1986. The results obtained are summarized as follows. 1. The mean rates of fertility and hatchability were 82.2${\pm}$1.37(X${\pm}$S.E.) and 79.0${\pm}$1.91%, respectively. 2. The mean rates of fertility and hatchability during brooding, growing and laying periods were 90.5${\pm}$1.69, 79.9${\pm}$2.28% and 80.6${\pm}$3.06%, respectively. 3. Average body weight at hatch, at ages of 18, 24, 44 and 72 weeks were 31.5, 0.43, 1209.3${\pm}$17.29, 1646.1${\pm}$25.90, 1975.3${\pm}$40.56 and 2096.7${\pm}$40.83g, respectively. 4. The age of the first egg was 166.5${\pm}$1.69 days old. Egg weights at first egg, at ages of 44 and 72 weeks were 35.7${\pm}$0.49, 48.8${\pm}$0.47 and 502${\pm}$0.44g, respectively. The numbers of egg production age to of 44 and 72 weeks were 69.5${\pm}$3.10 and 129.3${\pm}$5.56 eggs, respectively. 5. Between body weights and age at the first egg showed lower negative correlation. Body weights at ages of 24, 44 and 72 weeks showed highly positive correlation with egg weight, but a significant negative correlation with the number if egg production to ages of 44 and 72 weeks. The age at first egg was positively correlated with egg weight at first egg, but that was negatively correlated with the number of egg production to ages of 44 and 72 weeks.

• Korean Journal of Poultry Science
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• v.7 no.2
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• pp.54-76
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• 1980

A survey was conducted to determine the status of health and productivity of poultry farms in Korea. Area included Was Kyunggido where exist nearly 50% of national poultry population. From this area, 41 layer and 34 broiler farms covering 21 Countries were selected randomly for the survey. When farms were divided in the operation size, 95.1% of layer and 82.3% of broiler farms were classified as business or industrial level while the rest were managed in a small scale as part time job. Generally layer farms had been established much earlier than broiler farms. Geographically 10.7% of layer farms were sited near the housing area such as field foreast and rice field. No farms were located near the seashore. The distance from one farm from the other was very close, being 80% of the farms within the distance of 1km and as many as 28% of the farms within loom. This concentrated poultry farming in a certain area created serious problems for the sanitation and preventive measures, especially in case of outbreak of infectious diseases. Average farm size was 5,016${\times}$3.3㎡ for layers and 1,037${\times}$3.3㎡ for broilers. 89.5% of layer ana 70.6% of broiler farms owned the land for farming while the rest were on lease. In 60% of layer farms welters were employed for farming while in the rest their own labour was used. Majority of farms were equipped poorly for taking necessary practice of hygiene and sanitation. The amount of disinfectant used by farms was considerably low. As many as 97.6% of lave. farms were practised with Newcastle(ND) and fowl pox(F$.$pox) vaccine, whereas only 43.6% and 5.1% of broiler farms were practised with ND and F$.$pox vaccine, respectively. In 17-32.7% of farms ND vaccine was used less than twice until 60 days of age and in only 14.6% of farms adult birds were vaccinated every 4months. Monthly expense for preventive measures was over 200,000W in 32% of farms. Only 4.9-2.7% of vaccine users were soaking advice from veterinarians before practising vaccination, 85% of the users trusted the efficacy of the vaccines. Selection of medicine was generally determined by the farm owner rather than by veterinarans on whom 33.3% of farms were dependant. When diseases outbroke, 49.3% of farms called for veterinary hospital and the rest were handled by their own veterinarians, salesmen or professionals. Approximately 70% of farms were satisfied with the diagnosis made by the veterinarians. Frequency of disease outbreaks varied according to the age and type of birds. The livabilities of layers during the period of brooding, rearing ana adultwere 90.5, 98.9 and 75.2%, respectively while the livalibility of broilers until marketing was 92.2%. In layers, average culling age, was 533.3 day and hen housed eggs were 232.7. Average feed conversion rates of layers and broilers were 3.30 and 2.48, respectively. Those figures were considerably higher than anticipated but still far lower than those in developed countries.