• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.144-150
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• 2003

Reproductive biology and population dynamics of Latreutes planirostris were investigated on the south western waters of Korea from June 2001 to May 2002. This paper describes sex ratio, population growth, and reproductive aspects of Latreutes planirostris. Brood size was an isometric function of female carapace length. Based on dry weight, reproduction effort (mass of eggs/mass of female) averaged 0.23. Ovarian examination showed that there was significantly higher gonadosomatic index from May to September, with a peak in June. Statistical analysis revealed that the ovarian dry weight of females with eyed eggs was significantly higher than that of those with non-eyed eggs. This suggests that females were potentially consecutive breeders. Sex ratio showed that female is more numerous than male. Growth parameters mortality and recruitment were estimated by monthly length-frequency data. Growth parameters were estimated, using the seasonalized von Bertalanffy growth function model $(L\infty\;=\;12.70\;mm\;CL,\;K\;=\;0.87yr^{-1},\;C\;=\;0.96,\;WP\;=\;0.59)$. The recruitment pattern was twice a year.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.220-221
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• 2002

The planktonic shrimp, Acetes chinensis Hansen, 1919 inhabits the coastal areas of the Info-West Pacific, Korea, China, Taiwan, and Japan and is most abundant along the coastal areas of Yellow Sea. Several studies have locally examined aspects of reproductive biology of the species such as reproductive cycle, spawning, maturity, breeding pattern and fecundity. (omitted)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.317-318
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• 2001

In crustacea the molting cycle is the most important physiological process affecting growth, behaviour, reproduction and population dynamics through their life span. Particularly molt cycle is closely related to reproductive cycle, and it is important to determine the successive stages of molt cycle to understand reproductive phenomena including ovarian cycle and the development of the embryos in the marsupium. (omitted)

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.295-304
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• 1994

This paper describes some preliminary attempts to formulate simple mathematical models of the transmission dynamics of HIV infection in homosexual communities. In conjunction with a survey of the available epidemiological data on HIV infection and the incidence of AIDS, the model is used to assess how various processes influence the course of the initial epidemic following the introduction of the virus. Models of the early stages of viral spread provide crude methods for estimating the basic reproductive rate of the virus, given a knowledge of the incubation period of AIDS and the initial doubling time of the epidemic. More complex models are formulated to assess the influence of heterogeneity in sexual activity. This latter factor is shown to have a major effect on the predicted pattern of the epidemic.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.3
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• pp.77-85
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• 2015

One of the key factors of early development is the specification of competence between the oocyte and the sperm, which occurs during gametogenesis. However, the starting point, growth, and maturation for acquiring competence during spermatogenesis and oogenesis in mammals are very different. Spermatogenesis includes spermiogenesis, but such a metamorphosis is not observed during oogenesis. Glycosylation, a ubiquitous modification, is a preliminary requisite for distribution of the structural and functional components of spermatids for metamorphosis. In addition, glycosylation using epididymal or female genital secretory glycans is an important process for the sperm maturation, the acquisition of the potential for fertilization, and the acceleration of early embryo development. However, nonemzymatic unexpected covalent bonding of a carbohydrate and malglycosylation can result in falling fertility rates as shown in the diabetic male. So far, glycosylation during spermatogenesis and the dynamics of the plasma membrane in the process of capacitation and fertilization have been evaluated, and a powerful role of glycosylation in spermatogenesis and early development is also suggested by structural bioinformatics, functional genomics, and functional proteomics. Further understanding of glycosylation is needed to provide a better understanding of fertilization and embryo development and for the development of new diagnostic and therapeutic tools for infertility.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.646-653
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• 2003

Investigations were made on the population structure, sex ratio, growth, and recruitment patterns of Leptochela sydniensis in the southwestern coastal areas of Korea, between May 2000 and December 2001. Spawning period, fecundity, brood loss, reproductive output, and size at sexual maturity also were examined. The results of the sex ratio showed that females were more numerous than males during the overall study period. Parameters of growth were estimated using the modified von Bertalanffy growth function (VBGF) model incorporating seasonal variation into growth. Females grew somewhat faster and reached a larger size than males $(L\infty=12.80\;mm\;CL\;and\;K=0.70\;yr^{-1}\;or\;females,\and\;L\infty=12.08\;mm\;CL\;and\;K=0.69\;yr^{-1}$ for males). The structure of recruitment patterns obtained by the FiSAT program indicated one normally distributed group. Based on the occurrence of ovigerous females and the gonadosomatic index (GSI), the main spawning season was from June to August. Analysis of covariance indicated that brood loss was not observed during the incubation period. The size at which $50\%$ of females are mature is estimated as 5.48 mm CL.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.20-30
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• 2009

To study reproductive dynamics of a Gold-spotted pond frog (Rana chosenica) population located at Gangnae, Cheongwon, Chungbuk, Korea, we monitored the population over 207 days between April 17$^{th}$ 2007 and December 18$^{th}$ 2008 using a drift fence accompanied with 20 pitfall traps. The population was located in an agricultural wetland, compromising three small ponds. Gold-spotted pond frogs immigrated into the wetland between April 16$^{th}$ and June 17$^{th}$ and emigrated from the wetland between September 21$^{st}$ and November 12$^{th}$. Precipitation showed a positive correlation with the number of migrated frogs in Autumn 2007 and Spring 2008, but other environmental factors such as air and water temperatures and relative humidity did not show any significant relationships. In general, small frogs first migrated into and from the wetland, but the trend was not strong. Female gold-spotted pond frogs were bigger than males. During the autumn migration, small frogs of which snout-vent length was smaller than 20 mm were found, indicating that successful breeding occurred in the population. Our results could be useful to conserve this endangered species in Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2003.05a
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• pp.71-71
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• 2003

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.2
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• pp.89-95
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• 1999

This study investigates the population model of the spread of HIV/AIDS which the infection is generated by an infectious individual in a population of susceptible. A mathematical model is presented for the transmission dynamics of HIV infection within the communities of homosexual males. The pattern on the epidemic character of HIV, the causative agent of AIDS, was analysed by the mathematical model of AIDS system which is derived according to the ecological relationship between five epidemilogic states of individuals. The computer simulation was performed using real data and the following conclusions are drawn on the basis of the simulations. 1. The model structure and the algorithm described n the thesis is good. 2. In proportion to increase Ro, the population of AIDS patient increases and the time of its widespread reaches earlier. 3. The AIDS patients will be maximum between 7 and 21 years after an attack of AIDS and widespread between 10 and 20 years. 4. Considering the properties of the incubation periods, the maximum number of infected person is increased, and the attack rate is decreased.

• Korean Journal of Ichthyology
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• v.27 no.3
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• pp.217-227
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• 2015

Reproductive biology and population dynamics of Luciogobius guttatus were investigated. Higher gonadosomatic index (GSI) was observed from March~May. The fecundity ranged form 241 eggs at 3.1~4.0 cm (SL) to 716 eggs at 5.1~5.7 cm (SL). The relationship between length (SL) and fecundity (F) was $F=11.242SL^{2.464}$ ($R^2=0.65$) and fecundity increased with length. We estimated the SL at 50% group maturity as 2.6 cm. The spawning period was March~May. The von Bertalanffy growth function (VBGF) estimates were: $L_{\infty}=63.00mm$ TL; $K=0.85yr^{-1}$. The structure of recruitment pattern obtained by the FiSAT II program indicated one normally distributed group. The growth performance index (${\phi}$) was calculated with 3.53. Natural mortality rate (M) was $1.00yr^{-1}$.