• Journal of Ecology and Environment
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• 제35권4호
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• pp.301-306
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• 2012

Determination of the minimum population size is an important component for the ex situ conservation of an endangered species. Here, we present the identification of collection strategies that most efficiently captured the genetic diversity of Brasenia schreberi J.F. Gmelin (water-shield) in natural populations from the mainland (MGC) and Jeju Island (JNS) of South Korea, using amplified fragment length polymorphism (AFLP) markers. A total of 313 and 383 polymorphic bands were detected in the MGC and JNS populations, respectively. All of the 140 sampled ramets were distinguishable by the presence of distinct AFLP phenotypes. According to the simulation of the individual sampling by maximization sampling, 25 and 28 individuals captured all of the genetic diversity in the MGC population (mainland of South Korea) and the JNS population (Jeju Island), respectively. The level of genetic diversity of the core collections was similar to the entire collection, indicating that the core collections very well represent the diversity of the entire collection. We therefore suggest a management unit of B. schreberi based on the genetic information for assessing the minimum population size for its ex situ conservation.

• 한국발생생물학회지:발생과생식
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• 제16권3호
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• pp.205-217
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• 2012

The ovarian cycle, the biological minimum size, and artificial spawning frequency by artificial spawning induction of the female hard clam, Meretrix petechialis, were investigated by histological observations and morphometric data. The ovarian cycle of this species can be classified into five successive stages: early active stage, late active stage, ripe stage, partially spawned stage, and spent/inactive stage. The spawning period was from June to September, and the main spawning occurred between July and August when the seawater temperature exceeds over $20^{\circ}C$. The biological minimum size (shell length at 50% of first sexual maturity) in females were 40.39 mm in shell length (considered to be two years of age), and all clams over 50.1 mm in shell length sexually matured. In this study, the mean number of the spawned eggs by spawning induction increased with the increase of size (shell length) classes. In case of artificial spawning induction for the clams > 40.39 mm, the number of spawned eggs from the clams of a sized class was gradually decreased with the increase of the number of the spawning frequencies (the first, second, and third spawning). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning of this species was estimated to be 15-18 days (approximately 17 days).

• 한국패류학회지
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• 제27권1호
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• pp.43-53
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• 2011

The gametogenic cycle and the spawning season in female and male Cyclina sinensis were investigated by quantitative statistical analysis using an image analyzer system, and the biological minimum size (the size at 50% of sexual maturity) was calculated by combination of quantitative data by size and von Bertalanffy's equation. Compared the gametogenic cycle by quantitative statistical analysis with the previous qualitative results in female and male C. sinensis, monthly changes in female and male gametogenic cycles calculated by quantitative statistical analysis showed similar patterns to the gonadal stages in female and male reproductive cycles by qualitative histological analysis. Comparisons of monthly changes in the portions (%) of each area to eight kinds of areas by quantitative statistical analysis in the gonads in female and male C. sinensis are as follows. Monthly changes in the portions (%) of the ovary areas to total tissue areas in females and also monthly changes in the portions of the testis areas to total tissue areas in males increased in March and reached the maximum in May, and then showed a rapid decrease from June to October. Monthly changes in the portions (%) of oocyte areas to ovarian tissue areas in females and also monthly changes in the portions of the areas of the spermatogenic stages to testis areas in males began to increase in March and reached the maximum in June in females and males, and then rapidly dropped from July to October in females and males when spawnig occurred. From these data, it is apparent that the number of spawning seasons in female and male C. sinensis occurred once per year, from July to October. Monthly changes in the number of the oocytes per mm2 and in the mean diameter of the oocyte in captured image which were calculated for each female slide showed a maximum in May and reached the minimum from December to February. Therefore, C. sinensis in both sexes showed a unimodal gametogenic cycle during the year. The percentage of sexual maturity of female and male clams ranging from 25.1 to 30.0 mm in length was over 50% and 100% for clams over 40.1 mm length. In this study, the biological minimum size (sexually mature shell lengths at 50% of sexual maturity) in females and males were 26.85 and 26.28 mm, respectively.

• 한국패류학회지
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• 제29권4호
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• pp.313-323
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• 2013

Gonad development, the reproductive cycle, first sexual maturty and size at 50% of group sexual maturity (the biological minimum size) of Gomphina (Macridiscus) veneriformis were investigated for clams collected from the coastal waters of Donghae City, the East Sea of Korea by histological, and morphometric analysis. Monthly variations of the gonad index showed a pattern similar to that of the reproductive cycle. The reproductive cycle with the gonad developmental stages in female and male G. (M.) veneriformis can be classified into five successive stages: early active stage (December to March), late active stage (March to June), ripe stage (June to July), partially spawned stage (June to August), and spent / inactive stage (September to December). The spawning period continued from June to August, with a peak between July and August when the seawater temperature exceeds $20^{\circ}C$. The percentages of first sexual maturities of female and male clams ranging from 25.1 to 30.0 mm were 56.3% in females and 61.1% in males, and for clams over 30.1 mm shell length, it was 100%. Shell lengths at 50% of group sexual maturity (biological minimum size, $RM_{50}$) were 27.71 mm in females and 26.31 mm in males. Because harvesting clams < 26.31 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• 한국패류학회지
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• 제27권3호
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• pp.261-271
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• 2011

The gametogenic cycle, the spawning season and the biological minimum sizes in female and male Protothaca (Notochione) jedoensis were investigated by quantitative statistical analysis. In females, monthly changes in the percents of the follicle areas to the ovarian tissue areas and the percents of the oocyte areas to the ovarian tissue areas increased in February and reached the maximum in April, and then gradually decreased from May to July, with the spawning peak between June and July. In males, monthly changes in the percents of the testicular tissue areas to total tissue areas and the percents of the spermatogenic stage areas to the testicular tissue areas increased in February and reached the maximum in April, and then showed a rapid decrease from May to July. From these data, it is apparent that the number of spawning seasons in female and male P. (N.) jedoensis occurred once a year, from May to July. Therefore, P. (N.) jedoensis in both sexes showed a unimodal gametogenic cycle during the year. Compared the gametogenic cycle by quantitative statistical analysis in 2007 with the previous qualitative results of this species, the results of the gametogenic cycle calculated by quantitative statistical analysis showed some differentiations in the spawning seasons evaluated by the gonad index by qualitative histological analysis. The intervals of the beginning of two spawning seasons showed one month between the results of quantitative and qualitative analyses. The biological minimum sizes (considering to 50% of group sexual maturity) in female and male clams by quantitative analysis of this species are 32.01 mm in shell length in females and 30.58 mm in males, respectively. According to the mean shell length fitted to von Bertalanffy's equation, 30.58 and 32.01 mm in shell length were considered to be two years old. Therefore, we assume that both sexes of this population begin reproduction from two years of age.

• 한국환경과학회지
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• 제27권8호
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• pp.665-675
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• 2018

The purpose of this study was to identify the characteristics of the home range and habitat use of Rhinolophus ferrumequinum individuals that inhabit urban areas. The bats were tracked using GPS tags. For analysis of the home rage, Minimum Convex Polygon (MCP) and Kernel Home Range (KHR) methods were used. The landscape types of all positional information were analyzed using ArcGIS 9.3.1 (ESRI Inc.). The average home range of 16 R. ferrumequinum individuals was $68.63{\pm}25.23ha$, and the size of the overall home range for the females ($85.49{\pm}25.40ha$) was larger than that for the males ($51.76{\pm}8.30ha$). The highest average home range for the males was found in August ($61.21{\pm}0.01ha$), whereas that for the females was found in September ($112.27{\pm}5.94ha$). The size of 50% KHR ranged from a minimum of 13.26 ha to a maximum of 31.00 for the males and a minimum of 8.02 ha to a maxinum of 42.16 ha for the females, showing no significant differences between the two sexes. In addition, males and females showed no differences in the size of 50% KHR in the monthly comparisons. However, the females showed differences in the size of their core area between periods before and after giving birth. The comparisons between 100% MCP and 50% KHR showed that the types of habitats used by R. ferrumequinum were mostly forest areas, including some farmlands. In addition, comparisons with a land cover map showed that the proportion of broad-leaved forests was the highest, followed by that of mixed forests.

• 응용통계연구
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• 제15권1호
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• pp.1-8
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• 2002

예후인자의 범주화는 질병의 진단, 치료법 결정 및 임상시험의 참여기준 설정 등에 매우 유용하다. 예후인자의 범주화 방법으로는 생물학적 이론에 따라 경계값을 정하는 방법, 자료의 그래프를 이용하는 방법, 모든 가능한 경계 값들을 적용해보는 최소 유의확률 방법 등이 있다. 또한 최소 유의확률 방법의 다중검정문제를 보완한 몇 가지 방법들이 있다. 본 연구에서는 우리 나라에서 높은 발생률을 보이는 간세포암종의 절제술을 받은 환자들에 있어서 간 절제술 후 재발위험이 높은 군을 구별하는 한 근거로 종양의 크기를 범주화하기 위한 경계값을 결정하고자 하였다.

• Ocean Science Journal
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• 제42권2호
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• pp.69-79
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• 2007

A vertical transect with 4 km length was established for the macrofaunal survey on the Chokchon macrotidal flat in Kyeonggi Bay, Incheon, Korea, 1994. Tidal elevation (m) and sediment mean grain size $(\phi)$ were inversely predicted by the transfer functions from the faunal assemblages. Three methods: weighted average using optimum value (WA), tolerance weighted version of the weighted average (WAT) and maximum likelihood calibration (MLC) were employed. Estimates of tidal elevation and mean grain size obtained by using the three different methods showed positively corresponding trends with the observations. The estimates of MLC were found to have the minimum value of sum of squares due to errors (SSE). When applied to the previous data $(1990\sim1992)$, each of three inference models exhibited high predictive power. This result implied there are visible relationships between species composition and faunas' critical environmental factors. Although a potential significance of the two major abiotic factors was re-affirmed, a weak tendency of biological interaction was detected from faunal distribution patterns across the flat. In comparison to the spatial and temporal patterns of the estimates, it was suggested that sediment characteristics were the primary factors regulating the distribution of macrofaunal assemblages, rather than tidal elevation, and the species composition may be sensitively determined by minute changes in substratum properties on a tidal flat.

• 생태와환경
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• 제33권4호통권92호
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• pp.395-404
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• 2000

1997년 3월부터 1998년 3월까지 충청남도 부여군 세도면 모세올 지역의 농수로에서 채집한 왜몰개, Aphyocypris chinensis를 대상으로 생식생태를 조사하기 위하여 연간 생식소숙도지수(GSI), 간숙도지수(HSI), 난경조성과 생식소 발달과정 및 다른 번식특성들을 조사하였다. GSI 변화, 생식소의 발달과정 및 난경조성에 대한 분석결과, 1${\sim}$2월은 정체기, 3${\sim}$5월은 2차 성장기 및 성숙기, 6월에서 7월 사이는 완숙 및 산란기, 8${\sim}$9월은 퇴화 및 휴지기, 10${\sim}$12월은 1차 성장기로 나타낼 수 있었다. HSI는 연간 2개의 피크를 나타냈으며 GSI의 변화와는 역상관 관계를 보였다. 조사지점에서의 왜몰개 암컷의 포란수는 체중과 1차 함수적으로 증가하였으며 (r$^{2}$ =0.91, n = 347), 성비는 1.4 : 1 (암컷 : 수컷) 이었다. 생식가능한 최소 체장(fork length) 범위는 암컷에서는 38 mm, 수컷에서는 33mm로 조사되었다.

• Applied Biological Chemistry
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• 제29권3호
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• pp.311-317
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• 1986

공극(孔隙)의 크기가 다른 sand column에서 Zeolite의 유실실험(流失實驗)을 하여 Zeolite의 이동로(移動路)가 되는 최소(最少) 공극(孔隙)크기를 추적한 다음 실제(實際) 포장(圃場)에서의 Zeolite 유실가능성(流失可能性) 및 유실(流失) 가능(可能) 입자(粒子)의 크기를 추정실험(推定實驗)한 결과(結果)는 다음과 같다. 1. Sand column별 Zeolite의 유실량(流失量)은 $2{\sim}1>1{\sim}0.5>0.5{\sim}0.25mm$ sand column 순으로 증가하였다. 2. $1{\sim}0.5,\;0.5{\sim}0.25mm$ sand column에서 유실(流失)된 Zeolite는 모두 $2{\mu}m$ 이하(以下)의 입자(粒子)였다. 3. Zeolite가 유실(流失)될 수 있는 공극(孔隙)의 크기는 $150{\mu}m$ 이상(以上) 이었고 장천토양(長川土壤)의 심토(心土)는 $2{\mu}m$ 이하(以下)의 Zeolite가 유실(流失)될 가능성(可能性)이 있는 것으로 추정(推定)되었다. 4. 사질토양(砂質土壤)에 시용(施用)될 Zeolite의 최적입도(最適粒度)는 $2{\mu}m$ 이상(以上)의 획분(劃分)으로 추정(推定)되었다.