• The Korean Journal of Malacology
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• v.32 no.2
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• pp.83-93
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• 2016

For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.209-216
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• 2014

This study was undertaken to suggest an effective fisheries resources management system by using stock assessment and potential yield analyses of crucian carp population in the mid-upper system of the Seomjin River. Fieldwork was conducted seasonally from 2008 to 2009 in the mid-upper system of the Seomjin River. The stock assessment was carried out by the swept area method and the potential yield was estimated by improved fisheries resource potential estimation system based on the Allowable Biological Catch. Also, the yield-per-recruit analysis was used to review the efficient management implication of the resource, Carassius auratus. As a result, the age at first capture ($t_c$) was estimated as 1.468 year, converted body length (BL) was 10.8 cm. Meaning the current fishing intensities, the instantaneous coefficient of fishing mortality (F) was $0.067year^{-1}$, and the yield-per-recruit analysis showed that the current yield per recruit was estimated to be 15.999 g with F and $t_c$. The instantaneous rate of fishing mortality that provides for Allowable Biological Catch ($F_{ABC}$) based on the current $t_c$ and F was estimated as $0.618year^{-1}$. Therefore, the optimum fishing intensities could be achieved at the higher fishing intensity for Carassius auratus. The calculated annual stock of C. auratus was estimated as 7,608 kg, and the potential yield was estimated as 343 kg with $t_c$ and F at the fixed current level. Using yield-per-recruit analysis, if F and $t_c$ were set at $0.618year^{-1}$ and 2 year, the yield per recruit and total allowable catch would be predicted to increase to 62 g and 2,531 kg by about 3.9 times and 7.3 times, respectively.

• The Plant Pathology Journal
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• v.17 no.5
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• pp.276-280
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• 2001

Fusarium isolates of Gibberella fujikuroi species complex were obtained from sorghum grown in five provinces of Korea in 1996 and 1997. These isolates were characterized based on their mating behavior, mycotoxin production, and vegetative compatibility. Only three mating populations (A, D, and F) were recovered from a total of 155 isolates examined. The relative frequency of the mating populations was significantly different: F was predominant (80%), while D and A were observed at low frequencies of 9% and 3%, respectively. Female fertile isolates were more common within F (44 our of 124) than D (2 out of 14), while none of the five A isolates were female fertile. The inbreeding effective population sizes ($\textrm{N}_e$)for mating type and male/hermaphrodite ratios in mating populations A and D produced significant amounts of fumonisins, while F isolates produced none or only traces of fumonisin B$_1$. In contrast. F isolates produced higher amounts of moniliformin (average of 3,820 ppm) than A and D isolates (averages of 77 and 1,819 ppm, respectively). Fifty-one isolates were tested for vegetative compatibility using nitrogen non-utilization mutants of each isolate, and 44 vegetative compatibility groups (VCGs) were identified. A single VC type (VC1) was found in all of the five A isolates examined. Six of the D isolates examined consisted of three VC types: two for VC2, two for VC3, and the rest for VC4. All of the F isolates tested were incompatible in every combination and , thus, each constituted a unique VCG.

• Korea journal of population studies
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• v.13 no.2
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• pp.48-55
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• 1990

월리스의 생산력-소득수준 결정모형에서 자녀에 대한 수요가 자녀의 수와 자녀교육의 질에 대하여 비동차함수 형태를 취할때 자녀수요에 미치는 현존가격의 변화에 따른 소득효과 및 대체효과를 대수적으로 유도하고 이 의미를 기하학적으로 확인해 보는데 본 글의 의의가 있다. 대수적으로 자녀수요(C)를 단순히 자녀의 수(N)와 자녀 교육(Q)의 곱으로 C=NQ와 같이 나타낸 월리스의 모형에서 이를 C=f(N,Q)와 같이 일반적인 함수 형태를 취할때에 소비자 이론의 기본적인 작용 극대화를 통하여 자녀수요를 도출하였다. 기하학적으로는 대수적으로 도출된 자녀수요에 대한 가치효과들을 자녀의 수와 자녀 교육의 질에 대한 상대적 현존 가치를 고려하여 자녀수요의 변화, 자녀수 및 자녀 교육의 질 사이에 관계를 도시하였다.

• Economic and Environmental Geology
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• v.4 no.4
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• pp.225-234
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• 1971

With the advance of civilization and steadily increasing population rivalry and competition for the use of the sewage, culverts, farm irrigation and control of various types of flood discharge have developed and will be come more and more keen in the future. The author has tried to calculated a formula that could adjust these conflicts and bring about proper solutions for many problems arising in connection with these conditions. The purpose of this study is to find out effective sewage, culvert, drainage, farm irrigation, flood discharge and other engineering needs in the Taegu area. If demands expand further a new formula will have to be calculated. For the above the author estimated methods of control for the probable expected rainfall using a formula based on data collected over a long period of time. The formula is determined on the basis of the maximum daily rainfall data from 1921 to 1971 in the Taegu area. 1. Iwai methods shows a highly significant correlation among the variations of Hazen, Thomas, Gumbel methods and logarithmic normal distribution. 2. This study obtained the following major formula: ${\log}(x-2.6)=0.241{\xi}+1.92049{\cdots}{\cdots}$(I.M) by using the relation $F(x)=\frac{1}{\sqrt{\pi}}{\int}_{-{\infty}}^{\xi}e^{-{\xi}^2}d{\xi}$. ${\xi}=a{\log}_{10}\(\frac{x+b}{x_0+b}\)$ ($-b<x<{\infty}$) ${\log}(x_0+b)=2.0448$ $\frac{1}{a}=\sqrt{\frac{2N}{N-1}}S_x=0.1954$. $b=\frac{1}{m}\sum\limits_{i=1}^{m}b_s=-2.6$ $S_x=\sqrt{\frac{1}{N}\sum\limits^N_{i=1}\{{\log}(x_i+b)\}^2-\{{\log}(x_0+b)\}^2}=0.169$ This formule may be advantageously applicable to the estimation of flood discharge, sewage, culverts and drainage in the Taegu area. Notation for general terms has been denoted by the following. Other notations for general terms was used as needed. $W_{(x)}$ : probability of occurranec, $W_{(x)}=\int_{x}^{\infty}f_{(n)}dx$ $S_{(x)}$ : probability of noneoccurrance. $S_{(x)}=\int_{-\infty}^{x}f_(x)dx=1-W_{(x)}$ T : Return period $T=\frac{1}{nW_{(x)}}$ or $T=\frac{1}{nS_{(x)}}$ $W_n$ : Hazen plot $W_n=\frac{2n-1}{2N}$ $F_n=1-W_x=1-\(\frac{2n-1}{2N}\)$ n : Number of observation (annual maximum series) P : Probability $P=\frac{N!}{{t!}(N-t)}F{_i}^{N-t}(1-F_i)^t$ $F_n$ : Thomas plot $F_n=\(1-\frac{n}{N+1}\)$ N : Total number of sample size $X_l$ : $X_s$ : maximum, minumum value of total number of sample size.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.433-441
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• 2016

Clubroot caused by the protist Plasmodiophora brassicae is one of the most destructive diseases of Brassica crops. Developing Chinese cabbage cultivars with durable clubroot resistance (CR) is an important goal of breeding programs, which will require new genetic resources to be identified and introduced. In this study, we evaluated resistance to P. brassicae race 4 using 26 Chinese cabbage (B. rapa ssp. pekinensis ) cultivars compared to the clubroot-susceptible Chinese cabbage inbred line 'BP079' and the clubroot-resistant European turnip (B. rapa ssp. rapifera ) inbred line 'IT033820'. No symptoms of clubroot disease were found in 'IT033820' infected with P. brassicae race 4, whereas the Chinese cabbage cultivars exhibited disease symptoms to various degrees. The Chinese cabbage cultivars that were reported to be clubroot-susceptible were susceptible to P. brassicae race 4; however, seven of the 20 cultivars reported to be clubroot-resistant were susceptible to this race of P. brassicae to varying degrees. Resting spores of P. brassicae were abundant within the infected root tissues of 'BP079', as revealed by light microscopy and scanning electron microscopy (SEM), but they were not detected in root tissues of 'IT033820'. Although resting spores were not detected by light microscopy in root tissues of the clubroot-resistant Chinese cabbage cultivar 'Kigokoro 75', a few spores were observed by SEM. The $F_1$ hybrids from a cross between 'IT033820' and 'BP079' showed no disease symptoms, and all $BC_1P_1$ progenies from a cross between the $F_1$ hybrid and 'IT033820' exhibited a resistance phenotype. In the $BC_1P_2$ population from a cross between the $F_1$ hybrid and 'BP079', this trait segregated at a ratio of 3(R):1(S) (${\chi}^2=1.333$, p = 0.248) at a 5% significance level. Inoculated $BC_1P_2$ plants were either highly resistant or highly susceptible to the pathogen, indicating that the CR to race 4 of P. brassicae carried by 'IT033820' is dominant. In the $F_2$ population, this trait segregated at a ratio of 15(R):1(S) (${\chi}^2=0.152$, p = 0.696) at a 5% significance level, suggesting that CR in 'IT033820' is mainly controlled by two dominant genes. Therefore, 'IT033820' represents a promising genetic resource for developing durable CR breeding lines in Chinese cabbage.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.54.2-54.2
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• 2010

The most massive galactic globular cluster, $\omega$ Cen has been observed using recently mounted WFC3/UVIS cameras of Hubble Space Telescope at both near-UV and optical bands. We present the photometry of stars in the central region of $\omega$ Cen in F225W, F275W and F336W bands. The near-UV color-magnitude diagrams and color-color diagrams of stars in $\omega$ Cen show multiple red giant branches and main sequences as already discovered in both ground-based and HST/ACS observations in the optical bands. We modelled the stellar populations of $\omega$ Cen using Yonsei Isochrone, where $\alpha$-particles and helium enhancement processes have been included properly. We compare the best-fit stellar populations obtained from the current near-UV observations to the suggested stellar population models based on optical band data. We also discuss the methodological issues arising when dealing with the near-UV observations; red-leak in near-UV filters and the huge interstellar extinction in near-UV bands compared to the optical bands and its non-linear effect in color-magnitude diagrams.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.261-265
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• 2001

This study was carried out to select randomly amplified polymorphic DNA (RAPD) markers associated with grain weight of a large-grain mutant, Hyacp 39-26-1, derived from anther culture of a rice cultivar, 'Hwayeongbyeo'. The segregation mode for grain weight in an F$_2$ population from a cross, 'Hwayeongbyeo/Hyacp 39-26-1', showed a nearly normal distribution. One hundred and ninety-one F$_2$plants ranged from 21.8 g to 34.7 g in 1,000-grain weight with a mean of 26.8 g. Five hundred and twenty primers were used to detect the RAPD markers associated with the grain weight of the large-grain mutant. Of these primers, 54 primers showed polymorphism between 'Hwayeongbyeo' and 'Hyacp 39-26-1'. Four RAPD markers (OPB18, OPH07, OPT20, and OPX20) were significantly related to the grain weight of twenty one F$_3$ lines derived from the cross, 'Hwayeongbyeo/Hyacp 39-26-1'. This RAPD marker could facilitate the early and efficient selection of high-yield lines through improvement of grain weight in rice.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.6-11
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• 1990

Analysis of genetic structure in Kimpo natural population of Drosophila was carried out by utilizing the deleterious gene on the second chromosome of Drosophila melanogaster. Male flies tested were continuously collected for eight years; in late September 1974 and 1981-1987. The frequency of deleterious gene (lethal plus semilethal) ranged from 27.02% in 1983 to 41.48% in 1987, and the values estimated from the eight years samples are highly signihcent from each other with a homogenety test (X$^2$=52.0157, d.f.=28, P<0.005). Allelic rates ranged from 1.30% in 1981 to 5.03% in 1974. And the effective population size by using the rate of allelism was estimated average at 3, 300 pairs. Elimination rate by homozygous of lethal gene ranged from 0.0004 in 1984 to 0.0019 in 1974, and that is for smaller than mutation rate(0.005) at second chromosome. We suppose that stable frequency (about 20%) lethal genes of D. melanogaster in Kimpo natual population are maintained by invade of P-type mutator factor (P element) versus eliminated in heterozygous and homozygous condition of lethal gene.

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.05a
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• pp.244-245
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• 2001