• 제목/요약/키워드: Seasonal fluctuation

검색결과 243건 처리시간 0.032초

육계생산과 도계유통에 관한 조사연구 (A Study on Production, Dressing and Marketing of Broiler)

  • 오세정
    • 한국가금학회지
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    • 제10권1호
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    • pp.1-22
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    • 1983
  • The Purpose of this study is to examine both supply and demand side of broiler chicken in Korea. Especially the paper aims to investigate the broiler chicken production Dressing and marketing pattern which may affect the demand for it. It is generally understood that broiler chicken production becomes unstable because of frequent market price fluctuation mainly due to disequilibrium of quantities demanded ana supplied It is important to point out that marketing in the form dressed chicken has been enforced by the regulation in Seoul area since March 1st, 1983, though live birds have been customarily marketed for year. It is assumed that the subsituation of chicken meat for beef would save foreign exchanges, because increasingly large amount of beef is imported mainly thanked to a chronical shortage in local production. Main findings of this study may be summarized as follows: 1) Broiler chicker production has been rapidly increased recently, estimating 180-200 million head per year with the trend of contineous increase year after year. Price fluctuation during the year is found, especially summer and winter mainly due to seasonal demand change. It is known that mal-funconing of broiler chicken market may be one of the causes for a large Price fluctuation. Accordingly the increase of marketing efficiency may reduce the price fluctuation and also positively impact on creating demand for the chicken consumption. 2) It is also interesting to note that 90 percent of broilers are grown on the floor and almost 86 percent of total broilers composed of so called high-bros, weighing on an average more than 1.6kg per head Approximately 8 weeks are required for of around marketing birds at the feed efficiency of around 2.3-2.5 Average broiler farm raises between 1,000 and 2,000 head, showing a quite small scale of operation. Only a few sampled farmers follow an all-in and all-out method in broiler production.

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담팔수깍지벌레의 천적에 관한 연구 (Studies on the Natural Enemies of Protopulvinaria mangiferae(Green) (Homoptera : Coccidae))

  • 김종국;모리모토 카츠라
    • Journal of Forest and Environmental Science
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    • 제14권1호
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    • pp.128-137
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    • 1998
  • 담팔수깍지벌레의 천적 종류는 1차 기생벌 6종, 2차 기생벌 3종, 포식성 무당벌레 5종 및 풀잠자리류 1종등 총15종이 확인(確認)되었다. 1차 기생벌 가운데 Aneristus ceroplastae, Microterys flavus, Coccophagus yoshidae의 밀도가 높았으며, 최 우점종은 Aneristus ceroplastae이었다. Aneristus ceroplastae와 Coccophagus yoshidae는 단기생성(單寄生性)의 내부기생자(內部寄生者)이었으며 Microterys flavus는 다기생성(多寄生性) 내부기생자(內部寄生者)이었고 2차 기생벌 가운데 최우점종인 Tetrastichus sp.는 Aneristus ceroplastae와 Microterys flavus의 용에 기생하는 단기생성(單寄生性)의 외부기생자(外部寄生者)이었다. 또한 주요 기생벌의 기생율(寄生率) 및 계절적(季節的) 발생소장(發生消長)을 구명(究明)하였다. 포식성(捕食性) 천적(天敵)은 Rhyzobius forestieri와 Chilocorus kuwanae가 우점종이었으며 이들 종(種)에 대한 발생소장(發生消長) 및 포식량(捕食量)을 구명(究明)하였다. 특히 Rhyzobius forestieri는 담팔수깍지벌레를 포식하는 종으로 일본 구주지방에서 처음 기록(記錄)하였다.

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1999년 강진만 동물플랑크톤 군집의 분포 및 특성 (Community Structure and Distributions of Zooplankton in Gangjin Bay in 1999)

  • 허회권;김도현;안승환
    • 환경생물
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    • 제20권1호
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    • pp.46-54
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    • 2002
  • 1999년 2월부터 11월까지 강진만의 16개 조사정점에서 동물플랑크톤 군집의 특성을 파악하기 위하여 격월별 조사를 실시하였다. 동물플랑크톤은 9개의 분류군이 출현하였으며 평균 출현량은 2,028indiv. $m^{-3}$이었다. 월별 출현량은 2월에 최대 5,496 indiv. $m^{-3}$에서 11월에 최소 78 indiv. $m^{-3}$ 사이에서 변동하였다. 동물플랑크톤 중 요각류는 총 19종이 동정되었는데 월평균 출현량은 42-4,159 indiv. $m^{-3}$의 범위였고 Acartia omorii, Centrophages abdominalis, Paracalanus indicus 및 A. steueri가 우점하였다. 지각류는 4월에 최고값 765 indiv. $m^{-3}$로 출현하였다. 계절별로 2월에는 요각류 A. omorii와 Oithona davisae, 4월에 요각류 A. omorii, Eurytemora pacifica와 지각류 Evadne nordmanni, Podon polyphemoides, 6월에 요각류 Tortanus dextrilobatus와 십각류의 유생, 8월에 요각류 P. indicus와 지각류 E. tergestina와 Penilia avirostris, 10월에 요각류 A. erythraea, P. indicus, 그리고 11월에 요각류 P. indicus 및 모악동물 Sagitta crassa가 우점하였다.

경남 남부지역 양식어류 질병에 관한 역학적 연구 (The Epidemiological Study on fish Diseases in the Southern Area of Kyeognam)

  • 허정호;정명호;조명희;김국헌;이국천;김재훈;정태성
    • 한국임상수의학회지
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    • 제19권1호
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    • pp.14-18
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    • 2002
  • An epidemiological study was performed to evaluate the state of fish diseases between aquaculture fishes in the area of southern Kyeongnam, especially Tongyeong-si, Geoje-si, and Goseong-gun. Examination for a total of 91 cases was carried out for a variety of fishes, including Japanese flounder(Paralichthys olivaceus), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), sea breams(Pagrus major), and red drum (Sciaenops ocellatus) from November, 1999 to October, 2001. The investigation resulted in exploring 155 infectious diseases, including 62 Vibriosis, 16 Edwasiella infection, 11 Streptococcosis, 7 Pseudotuberculosis, 15 Scuticociliatida infection, 20 Gill flukes, and 9 Trichodiniasis. When the infections were classified according to fish species, Japanese flounder was infected by 30 Vibrio spp., 16 Edwardsiella tarda, 6 Streptococcus spp., 12 Scuticociliatida infection. In case of sea bass, 10 Vibrio spp. was able to isolate out of 10 outbreaks, on the other hand, rock fish was dominantly infected by gill flukes since it was observed 12 out of a total of 20 cases. With reference to seasonal fluctuation, Vibrio spp. infection was continually observed through all seasons but Edwardsiella septicaemia, Streptococcosis and Pseudotuberculosis was mainly isolated in summer and autumn when the water temperature was raised high. Scuticociliatida infection was frequently occurred from late autumn to early spring but gill flukes were watched all the year regardless of temperature. As regards, multiple infection, 47 out of 91 cases was Identified to have involved in more than 2 pathogens, especially Vibrio spp. was highly mixed with other pathogens since 42 out of 47 cases was mixed with Vibrio spp.

아산만 저어류 -III. 정점간 양적 변동과 종조성- (The Demersal Fishes of Asan Bay -III. Spatial Variation In Abundance and Species Composition-)

  • 이태원
    • 한국수산과학회지
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    • 제26권5호
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    • pp.438-445
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    • 1993
  • 1991년 가을에는 1992년 여름 사이 아산만에서 otter trawl로 저어류 자료를 수집하여 저어류의 계절 및 정점간의 군집구조를 분석하였다. 출현한 34종 중, 참서대(Cynoglossus joyneri), 민태(Johnius belengeri), 곤어리(Thrissa koreana) 및 등가시치(Zoarces gillii)가 총 채집개체수의 $93\%$를 차지하였다. 위의 4종 중 부어류인 곤어리를 제외한 우점 3종은 저질이 세립질인 만 내부에서 생물량이 많았다. 각 계절 정점간 군집구조를 rank correlation을 이용하여 주성분 분석한 결과, 정점간에는 큰 차이가 없었고 계절에 따른 군집구조 변화는 뚜렷하였으며, 그 변화는 수온, 혹은 수온과 상관관계를 갖는 요인에 의하여 좌우됨을 알 수 있었다. 조사해역은 수온의 연교차가 크고, 조류에 의한 해수의 혼합이 활발하여 이에 적응한 소수종이 우점하고 이 우점저어류는 퇴적물의 입도에 따라 그 분포가 결정되지만, 출현 개체수가 적은 대부분의 종은 정점간에 큰 차이를 보이지 않고 계절에 따라 군집구조가 변하여 가는 것으로 보인다.

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여수 낭도 연안에서 낭장망에 어획된 어류의 종조성 및 계절변동 (Seasonal Fluctuations and Species Composition of Fish Collected by Long-bag Stow Net in Nang-island, Yeosu)

  • 유태식;윤병일;김준;한경호
    • 한국어류학회지
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    • 제32권2호
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    • pp.91-96
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    • 2020
  • 여수 낭도 연안에서 낭장망에 어획된 어류의 종조성 및 계절 변동을 연구하기 위해 2017년에 계절별로 4개의 정점에서 진행하였다. 어획된 어류는 총 9목 26과 37종, 10,208개체가 어획되었다. 농어목이 11과 16종으로 가장 많이 출현하였고, 우점종은 멸치(4,886개체, 47.9%), 보구치(842개체, 8.2%), 준치(369개체, 3.6%) 순이었다. 다양도는 1.24~3.23 범위를 보이며 5월이 가장 높았고, 우점도는 22.4~78.7% 범위를 보이며 11월이 가장 높았다.

Seasonal and Inter-annual Variations of Lake Surface Area of Orog Lake in Gobi, Mongolia During 2000-2010

  • Yang, Hee-Jae;Lee, Eun-Hye;Do, Na-Young;Ko, Dong-Wook;Kang, Sin-Kyu
    • 대한원격탐사학회지
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    • 제28권3호
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    • pp.267-276
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    • 2012
  • Terminal lakes are widely distributed in the arid and semi-arid Gobi of Mongolia, and serves as important water resource for local people and livestock. However, such lakes are subject to great fluctuations in its size depending on climatic conditions and human water utilization. The Orog Lake is one such example that has shown remarkable fluctuation in recent years. In this study, we investigated the temporal changes of Orog Lake surface area by using 16-day MODIS 250 m NDVI products from 2000 to 2010. The results were compared with climate variability represented by monthly precipitation and temperature. Our results show that the Orog Lake gradually shrank for the period from 2000 to 2010, but with a significant range of seasonal and inter-annual variability. The lake area showed considerable seasonal variations, as it expanded in spring and fall, primarily due to snow melt and summer precipitation, respectively. Extreme drought period from 2000 to 2002 triggered the substantial reduction in lake area, leading to dry-up in year 2005, 2006, 2007, and 2009. After dry-up once occurred in 2005, the lake repeated reappearance and disappearance depending on seasonal and annual precipitation. Our findings implicate that the ground water fluctuated around the lake bottom level since 2005. This suggests the highly vulnerable nature of Orog lake, which greatly depends on future precipitation change.

낙동강유역에서 위성영상을 이용한 보 건설 전후 수온의 계절변화 (Seasonal Variation of Water Temperature Before and After Weir Construction Using Satellite Image in the Nakdong River)

  • 김상우;김해동;임진욱;안지숙
    • 한국환경과학회지
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    • 제24권11호
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    • pp.1417-1430
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    • 2015
  • In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.

낙동강 하구해역에서 저인망에 의해 어획되는 어류의 종조성 및 계절 변동 (Seasonal Variations in Species Composition and Abundance of Fishes Collected by an Otter Trawl in Nakdong River Estuary)

  • 허성회;정석근
    • 수산해양기술연구
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    • 제35권2호
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    • pp.178-195
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    • 1999
  • 낙동강 하구 주변 해역에서 1987년 2월부터 1988년 1월까지 1년 동안 매월 소형 기선저인망(otter trawl)을 이용하여 어류의 종조성 및 계절변동을 조사하였다. 조사기간 동안 100개 어종에 속하는 23,008마리의 어류가 채집되었다. 가장 많이 채집된 어종은 실양태(Repomucenus valenciennei), 흰베도라치(Pholis fangi), 주둥치(Leiognathus nuchalis), 전갱이(Trachurus japonicus), 밴댕이 (Sardinella zunasi)였는데, 이들 5어종은 총 개체수의 63.0%와 생체량의 47.8%를 차지하였다. 계절별 우점종을 보면, 봄에는 흰베도라치와 실양태, 여름에는 실양태와 참서대(Cynoglossus joyneri), 가을에는 열동가리돔(Apogon lineatus)과 청멸(Thryssa kammalensis), 그리고 겨울에는 설양태, 주둥치, 밴댕이 등이 우점종으로 나타났다.어종수, 채집 개체수 및 종다양도지수는 뚜렷한 계절 변동을 보였다. 또한 어종 수 및 채집 개체수는 정점에 따라 차이를 보였는데, 낙동강 하구쪽으로 갈수록 어종수 및 채집 개체수가 감소하였다. 수온은 어류 종조성의 계절변동에 가장 큰 영향을 주는 요인이었으며, 염분은 어류의 공간 분포에 영향을 주는 것으로 나타났다.

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일별, 월별 의도적 자해의 사망 양상에 관한 연구: 2011 인구동태동계자료 중심으로 (Daily and Monthly Death Pattern an Intentional Self-harm by Hanging, Strangulation and Suffocation in Korea, 2011)

  • 박상화;임달오
    • 보건행정학회지
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    • 제23권3호
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    • pp.260-265
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    • 2013
  • Background: The aim of this study was to examine the seasonal variation of death from intentional self-harm by hanging, strangulation and suffocation (HSS: Korean Standard Classification of Diseases-6 code: X70) using the 2011 death registry data. Methods: The analysis was based on data of 8,359 HSS deaths from 2011 national vital statistics in Korea. Daily, weekly, and monthly death pattern on HSS were used to examine the relationship seasonal variation and HSS deaths. Results: A total of 8,359 HSS deaths occurred in 2011, with a mean age of 50.6 years. The HSS death rate (per 100,000) was 25.5 in male and 10.8 in female. In one day 17.6 males and 8.0 females occurred HSS death on average. The number of HSS death per day was the highest on 8th June (45 deaths), and lowest on 1st February (7 deaths) during the period. The variations of daily HSS death showed wide fluctuation from a peak of 34 to 45 deaths (29th May to 9th June) to a trough of 17-26 deaths (10th-13th September: the Korean thank-giving consecutive holidays), 13-20 deaths (2nd-5th February: the new year's day by the lunar calendar) and 8-9 deaths (24th-25th December: Christmas holidays). There were no significant difference between gender and seasonal variation (month, season, and week). Conclusion: The mean number of HSS death per day was highest in June (30.6 deaths), and months with the lowest number of deaths was January and December (range, 19.4 to 19.6 deaths). HSS death were more prevalent during summer and spring and were less likely to occur during winter. On Saturdays (21.0 deaths), the number of HSS death per day was the lowest, and Monday (27.9 deaths) was the highest. HSS death was less likely to occur on holidays (21.4 deaths). There was significant seasonal variation in HSS death by weekly and monthly (p<0.01).