• 제목/요약/키워드: maximum population density

검색결과 108건 처리시간 0.025초

피조개의 양식에 관한 생물학적 연구 I.부유유생의 분포 (Biological Studies On Arkshell Culture I. Distribution Of Drifting Larvae Of Te Arkshell, Anadara broughtonii Schrenck)

  • 유성규;박경양;유명숙
    • 한국해양학회지
    • /
    • 제12권2호
    • /
    • pp.75-81
    • /
    • 1977
  • 피조개는 우리나라의 내만이나 내해의 비교적 수심이 깊은 곳에 사는 대형종으로 조개류 중에서 가장 값비싼 중요양식종이다. 이 종의 양식을 위한 관심이 컸고, 많은 노력도 해 왔으나 양식의 기본이 되는 종묘생산이 제대로 되지않아 그 양식은 언제나 형식에 지나지 않았다.

  • PDF

한국 완도연안 비단가리비(Chlamys farreri)의 성장과 산란 (A Study on the Growth and Spawning of Korean Scallop (Chlamys farreri) around Wando, Korea)

  • 강태구;장창익
    • 수산해양기술연구
    • /
    • 제36권3호
    • /
    • pp.210-221
    • /
    • 2000
  • 완도연안의 비단가리비 개체군을 대상으로 자원생태학적 특성을 규명하기 위해 1998년 11월부터 1999년 10월까지 서식환경 및 밀도조사를 하였고, 패각에 나타난 윤문을 이용하여 연령과 성장을 구명하고, 생식소 난성숙비, 숙도지수의 변화, 포란수 측정 등으로부터 성숙과 산란에 대하여 조사하였다. 1. 수온 및 비중의 범위는 7.6∼25.9$^{\circ}C$, 1.0188∼l.0260였고 DO와 pH는 각각 6.48∼9.50ppm, 8.17∼8.80의 범위였다. 2. 저질상태에 따른 서식밀도는 암반과 자갈에서 28.83 마리/100㎡의 가장 높은 서식밀도를 보였고, 전체의 82,4%가 서식하였다. 3. 각장 (SL)과 각고 (SH)와의 관계는 SH=1.021SL+2.211 (R$^2$= 0.989), 각장과 전중량(TW)의 관계는 TW=$0.0003SL^{2.837}$ (R$^2$= 0.980)였다. 4. von Bertalanffy 성장식의 매개변수 추정치를 보면 이론적 최대각고($SH_{\infty}$)는 117.4mm, 성장계수 (K)는 0.612/yr, 각고가 0일 때의 이론적인 연령 ($t_{0}$)는 -0.017세였다. 5. 50% 군성숙연령은 0.21세로 이 때의 군성숙 각고는 18.3mm였다. 산란기는 6∼7월과 10월 연 2회 추정되었으며, 포란수 (Fc)에 대한 각장 (SL) 및 생식소중량 (GW)의 관계는 Fc = $697.03SL^{2.683}$ (R$^2$= 0.984), Fc =10,076,090GW + 15,608,781 (R$^2$= 0.990)로 나타났다.

  • PDF

충남연안 키조개의 자원생물학절 연구 1. 환경특성이 분포양상에 미치는 영향 (Biological Resources of Pen Shell, Atrina (Servatrina) pectinata japonica in the Coastal Waters of Chungchung-namdo, Korea. 1. Effects of Environmental Factors on Distribution Pattern)

  • 홍승현;마채우;오철웅
    • 한국패류학회지
    • /
    • 제18권1호
    • /
    • pp.53-59
    • /
    • 2002
  • 충남 연근해역의 키조개 개체군을 대상으로 자원생태학적 특성을 규명하기 위해 1999년 4월부터 6월까지 조사가능한 212개 조사정점에 대해 현장조사를 실시하였다. 본 조사를 통해 서식환경 및 분포밀도와 특성을 살펴보고, 자원량을 추정하였다. 충남 연근해역은 3.9-75.9 m의 수심범위를 가지고, 평균수심이 28.5 m (SE = 0.97)이며, 저층의 환경특성은 평균수온 14.$0^{\circ}C$, 투명도 4.8 m, 부유물질 48.0 mg/l이었다. 해역의 88.0%가 사질함량이 50% 이상인 니사질과 사질로 구성되었으며, 조사해역에서 키조개 자원의 분포밀도는 18.0-30.8% m의 수심범위와 사질 함유량이 50% 이상인 니사질 해역에서 높다. 조사해역에서 키조개는 단위면적 40 m$^2$내에서 5 개체 미만이 어획된 해역은 전 서식면적의 54.9%, 5 개체 이상 10개체 미만의 개체가 어획된 해역은 9.9%, 10개체 이상 20개체 미만의 개체가 어획된 해역은 11.3%, 20개체 이상 50개체 미만의 개체가 어획된 해역은 16.9%, 50개체 이상이 어획된 해역은 7.0% 이었다.

  • PDF

고성군 용산리의 두 저수 수계에서 어류의 다양성과 밀도 효과 (Density Effect and Diversity of Fish in Water System at Both Reservoirs in the Youngsan-ri, Goseong-gun)

  • 허만규;최병기
    • 생명과학회지
    • /
    • 제25권5호
    • /
    • pp.533-538
    • /
    • 2015
  • 경상남도 고성군 거류면 용산리 신은저수지 수계 4곳과 정촌 저수지 1곳 수계에서 어류 다양성 분석을 실시하였다. 인위적 교란과 환경변화에 따른 집단조절을 유도하는 밀도 의존성을 평가하였다. SMATR freeware를 사용하여 어류 밀도에 영향을 미치는 환경 요인 분석을 실시하였다. 2012년에 4과 8속 9종 158개체가 동정되었다. 비교적 풍부한 어종은 참붕어(Pseudorasbora parva)로 빈도는 33.1%였다. 그 다음은 송사리(Oryzias latipes)로 28.8%였다. 2012년에는 4곳에서 밀도 효과가 감소하였다. 신은저수지의 Shannon-Weaver의 다양도 지수(H’)는 정촌 저수지의 다양도와 유사하였다. 종 다양도는 0.645에서 2.105로 다양하게 나타났다. 상류지역의 다양도(H’)는 중류와 하류지역보다 높았다. 풍부도 지수 역시 상류가 하류보다 높았다. 강의 하류 두 지점을 제외한 최대 가능성 분석을 이용하면 한 지점에서 다른 지점으로 이동한 5종의 가능성은 평균 0.623이였다. 특히 신은저수지와 정촌저수지 간 이동 가능성은 높았다(평균 0.681). 이는 두 저수지간 지리적으로 짧은 탓에 기인한다(50 m). 나머지 4종에 대한 최대 이동가능성은 유의성이 없어 지점간 유사함을 시사한다.

MFC의 금속 및 탄소전극에 의한 전기생산 특성과 오염저감 효과 (Electricity Generation and De-contamination Effect for Characteristic Electrode Material in a Microbial Fuel Cell System Using Bay Sediment)

  • 권성현;송형진;이은미;조대철;이인형
    • 한국환경과학회지
    • /
    • 제19권8호
    • /
    • pp.951-960
    • /
    • 2010
  • Sediment works as a resource for electric cells. This paper was designed in order to verify how sediment cells work with anodic material such as metal and carbon fiber. As known quite well, sediment under sea, rivers or streams provides a furbished environment for generating electrons via some electron transfer mechanism within specific microbial population or corrosive oxidation on the metal surfaces in the presence of oxygen or water molecules. We experimented with one type of sediment cell using different anodic material so as to attain prolonged, maximum electric power. Iron, Zinc, aluminum, copper, zinc/copper, and graphite felt were tested for anodes. Also, combined type of anodes-metal embedded in the graphite fiber matrix-was experimented for better performances. The results show that the combined type of anodes exhibited sustainable electricity production for ca. 600 h with max. $0.57\;W/m^2$ Al/Graphite. Meanwhile, graphite-only electrodes produced max. $0.11\;W/m^2$ along with quite stationary electric output, and for a zinc electrode, in which the electricity generated was not stable with time, therefore resulting in relatively sharp drop in that after 100 h or so, the maximum power density was $0.64\;W/m^2$. It was observed that the corrosive reaction rates in the metal electrodes might be varied, so that strength and stability in the electric performances(voltage and current density) could be affected by them. In addition to that, COD(chemical oxygen demand) of the sediment of the cell system was reduced by 17.5~36.7% in 600 h, which implied that the organic matter in the sediment would be partially converted into non-COD substances, that is, would suggest a way for decontamination of the aged, anaerobic sediment as well. The pH reduction for all electrodes could be a sign of organic acid production due to complicated chemical changes in the sediment.

Bisphosphonates for Osteoporosis in Nonmetastatic Prostate Cancer Patients Receiving Androgen-deprivation Therapy: A Systematic Review and Meta-analysis

  • Ding, Hui;Yang, Li;Du, Wan;Teng, Yang;Fu, Sheng-Jun;Tao, Yan;Lu, Jian-Zhong;Wang, Zhi-Ping
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제14권5호
    • /
    • pp.3337-3343
    • /
    • 2013
  • This systematic review was conducted to assess the efficacy and safety of bisphosphonates for prevention and treatment of osteopenia or osteoporosis in men with non-metastatic prostate cancer receiving androgendeprivation therapy. We searched for randomised controlled trials (RCTs) of bisphosphonates compared with placebo from Pubmed, Embase, the Cochrane Library, and ISI - Science Citation Index. Meta-analyses of prespecified outcomes (bone mineral density, fractures, and adverse events) were performed using Review Manager. Ten RCTs with a total patient population of 1,017 were identified. There was generally more improvement in bone mineral density of the lumbar spine for patients who received bisphosphonate treatment than placebo or other medical treatment at 12 months (WMD 6.02,95%CI 5.39 to 6.65). Similar effects were also observed for total hip, trochanter or femoral neck bone mineral density. However, there was no significant reduction in fractures. Fever and gastrointestinal symptoms were the most common adverse events (10.4% vs. 1.2%; 0.10% vs. 0.03%). Currently, our meta-analysis suggested that oral and intravenous bisphosphonates caused a rapid increase in spine and hip or femoral BMD in non-metastatic prostate cancer patients receiving androgen-deprivation therapy. Fever and gastrointestinal symptoms were common with the use of bisphosphonates. These short-term trials (maximum of 12 months) did not show fracture reduction. In future, more efficient performance of higher quality, more rigorous, large sample, long-term randomised controlled trials (>12 months) are needed where outcomes are detailed.

Effects of Temperature and Packaging on the Growth Kinetics of Clostridium perfringens in Ready-to-eat Jokbal (Pig's Trotters)

  • Park, Hee-Jin;Na, Yu-Jin;Cho, Joon-Il;Lee, Soon-Ho;Yoon, Ki-Sun
    • 한국축산식품학회지
    • /
    • 제34권1호
    • /
    • pp.80-87
    • /
    • 2014
  • Ready-to-eat (RTE) Jokbal (Pig's trotter), which consists of pig's feet cooked in soy sauce and various spices, is a very popular and widely sold in Korean retail markets. Commercially, the anaerobically packed Jokbal have also become a popular RTE food in several convenience stores. This study evaluates the effects of storage temperature and packaging methods for the growth of C. perfringens in Jokbal. Growth kinetic parameters of C. perfringens in aerobically and anaerobically packed Jokbals are determined at each temperature by the modified Gompertz equation. The lag time, specific growth rate, and maximum population density of C. perfringens are being analyzed as a function of temperature and packaging method. The minimum growth temperature of C. perfringens in aerobically and anaerobically packed Jokbal is $24^{\circ}C$ and $18^{\circ}C$, respectively. The C. perfringens in Jokbal did not grow under conditions of over $50^{\circ}C$ regardless of the packaging methods, indicating that the holding temperature of Jokbal in markets must be maintained at above $50^{\circ}C$ or below $18^{\circ}C$. Growth of C. perfringens in anaerobically packed Jokbal is faster than in aerobically packed Jokbal when stored under the same conditions. This indicates that there are a higher risks associated with C. perfringens for anaerobically packed meat products.

서울과 여수지역에 HadCM3를 적용한 냉」난방도일의 변화량 분석 (Analysis of the cooling and heating degree days in the Seoul and Yeosu, where HadCM3 is applied)

  • 유호천;노경환
    • KIEAE Journal
    • /
    • 제9권4호
    • /
    • pp.11-16
    • /
    • 2009
  • To act and respond to the climate changes and to bring about power-saving in buildings, the changes in the atmospheric data in Korea are recorded and assessed. For the two regions representative of Korea, the data obtained from HadCM3 and actual data are compared and analyzed so as to concretely evaluate and confirm the changes taking place in the cooling and heating degree days in Korea. For the past 40 years, from 1996 to 2005, the number of heating degree days was on the decline and in the two representative regions, between 1980's and 1990's, the number of decrease in the heating degree days had been quite large. The number of cooling degree days showed a trend of increase since the 1970's and just as in the case of heating degree days, the extent of increase was quite large between the 1980's and the 1990's. The results of comparison of the number of heating and cooling degree days, one obtained from the "Korea Meteorological Administration" and another from the HadCM3 data (E127.5,N37.5,E127.5,N35), which is one of the ways of predicting the climate, showed similar trends in the number of heating degree days in the Yeosu area. However, in the case of the number of heating degree days in Seoul and the number of cooling degree days both in Seoul and Yeosu, the differences in the number ranged from a minimum of 300 days to a maximum of 1500 days. This could be attributed to the grid points used in the HadCM3, the differences in the values of latitudes and longitudes of these two locations considered in this study, topographical differences, heat island effect caused by population density etc. and while using the HadCM3, these variables factors must be taken into consideration.

수화를 형성하는 Mallomonas elongata (Synurophyceae) 의계절적 변동과 증식 특성에 대한온도와 pH의 영향 (Effects of Temperature and pH on Seasonal Changes and Growth Characteristics of a Bloom Forming Mallomonas elongata (Synurophyceae))

  • 이경락;김진희;윤호성;김한순
    • 생태와환경
    • /
    • 제38권4호통권114호
    • /
    • pp.503-509
    • /
    • 2005
  • 작은 부영양 저수지에서 수화를 형성하는 Mallomonas elongata의 계절적 변동(2004년 10월-2005년 9월)과 온도와 pH에 대한 증식 특성을 실험실 배양을 통해 조사하였다. 수온 12-$18^{\circ}C$, pH8.4-9.5의 범위를 나타낸 3월 말에서 4월 초의 짧은 기간 동안 M. elongata의 심한 bloom (최고 17,600 cells $mL^{-1}$이 발생하였다. 이 저수지로부터 분리한 M. elongata의 batch culture를 통한 다양한 온도에 대한 성장 반응은 bloom을 형성 하였을 때의 저수지 수온과 유사한 $15^{\circ}C$ 에서 최대성장률을 나타내었다. 반면 pH에 대한 증식 특성은 bloom 형성기의 저수지 pH 범위 보다 낮은 pH 6에서 최대 성장률을 나타내었다.

저장온도에 따른 마른김(Pyropia pseudolinearis)의 Bacillus cereus 성장예측모델 개발 (Predictive Growth Models of Bacillus cereus on Dried Laver Pyropia pseudolinearis as Function of Storage Temperature)

  • 최만석;김지윤;전은비;박신영
    • 한국수산과학회지
    • /
    • 제53권5호
    • /
    • pp.699-706
    • /
    • 2020
  • Predictive models in food microbiology are used for predicting microbial growth or death rates using mathematical and statistical tools considering the intrinsic and extrinsic factors of food. This study developed predictive growth models for Bacillus cereus on dried laver Pyropia pseudolinearis stored at different temperatures (5, 10, 15, 20, and 25℃). Primary models developed for specific growth rate (SGR), lag time (LT), and maximum population density (MPD) indicated a good fit (R2≥0.98) with the Gompertz equation. The SGR values were 0.03, 0.08, and 0.12, and the LT values were 12.64, 4.01, and 2.17 h, at the storage temperatures of 15, 20, and 25℃, respectively. Secondary models for the same parameters were determined via nonlinear regression as follows: SGR=0.0228-0.0069*T1+0.0005*T12; LT=113.0685-9.6256*T1+0.2079*T12; MPD=1.6630+0.4284*T1-0.0080*T12 (where T1 is the storage temperature). The appropriateness of the secondary models was validated using statistical indices, such as mean squared error (MSE<0.01), bias factor (0.99≤Bf≤1.07), and accuracy factor (1.01≤Af≤1.14). External validation was performed at three random temperatures, and the results were consistent with each other. Thus, these models may be useful for predicting the growth of B. cereus on dried laver.