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Dynamic Changes of Dissolved Oxygen during Summer Monsoon (하절기 장마동안 용존산소의 역동적 변화)

An, Kwang-Guk
- Korean Journal of Ecology and Environment
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- v.33 no.3 s.91
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- pp.213-221
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- 2000
Seasonal oxygen content and deficit rates were evaluated from 17 sites of Taechung Reservoir during 1993${\sim}$1994. In 1993, river inflows peaked during the monsoon in July${\sim}$August and disrupted thermal stratification and anoxic layers in the headwaters, thereby confining the anoxia to the mid-lake and downlake reach. The volume of anoxic water with < 4 mg/l DO comprised only < 10% of the total lake volume in this period. In contrast, during monsoon 1994, 85% of total lake volume was subject to hypoxic conditions with oxygen concentrations < 30% saturation, resulting in massive fishkills (Hypomesus olidus). Relative areal oxygen deficit (RAOD) was -0.024mg O$_{2}$cm$^{-2}$d$^{-1}$ during monsoon 1993, whereas it rapidly decreased at the rate of 0.080mg O$_{2}$cm$^{-2}$d$^{-1}$ during monsoon 1994. Anoxic factor (AF) showed a same interannual pattern as the RAOD and was greater >50 d in 1994 (76.5 d) than 1993 (21.3 d). Thus, the reservoir showed a river-characteristics (6${\sim}$11 mg/l DO) in 1993 while lacustrine conditions (<4mg/l DO) dominated in 1994. Regression analysis showed that the variation of summer DO was mostly determined (R$^{2}$=0.99, p<0.0001) by inflow. These findings suggest that the primary factor regulating the oxygen content in this system during summer is an intensity of the monsoon rain.
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Abundance of Argentine shortfin squid, Illex argentinus(Castellanos) in Relation to Fluctuation of Water Temperature in the Southwestern Atlantic Ocean (수온변동에 따른 아르헨티나 짧은지느러미오징어, Illex argentinus의 풍도 변화)

Kim, Yeong-Seung;Kim, Doo-Nam
- Journal of the Korean Society of Fisheries and Ocean Technology
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- v.40 no.4
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- pp.282-294
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- 2004
Catches of Argentine shortfin squid Illex argentinus showed a sharp decrease, reaching 99,000ton in 1993 and 56,700ton in 1994, and then increased again reaching 130,300ton in 1997 from 78,600 ton in 1996. The Korean squid jigging fishery around Falkland for Illex argentinus commences usually its operation in January and lasts August and peak in catch was showed from March to May. To elucidate possible environmental effects on their abundance during the main fishing season in 1993-1994 and 1996-1997, sea surface temperatures were used as an indicator of the position and strength of the oceanographic structures in the Southwestern Atlantic Ocean. The high catch and catch per unit effort of Illex argentinus was showed when the Faliland Current was not affected in the fishing area in 1993 and 1997. But they were sharply decreased from the middle of April 1994 and the late of April 1996 when the Faliland Current directly affects the fishing ground.
https://doi.org/10.3796/KSFT.2004.40.4.282 인용 PDF KSCI

A Study on the Respiratory System Health Condition of Dental Laboratory Technicians in Jullabuk-do (전라북도 치과기공사들의 호흡기계 건강에 관한 조사연구 (1993년도와 2001년도 비교연구))

Choi, Un-Jea;Shin, Moo-Hak;Lee, In-Kyu;Chung, Hee-Sun
- Journal of Technologic Dentistry
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- v.24 no.1
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- pp.19-31
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- 2002
The purpose of this study was to examine the respiratory system health condition of dental technicians and to be of use for more successful health management and health promotion for them. The subjects in this study were 155 dental technicians who were working in North Jeolla province. Out of them, 70 dental mechanics were investigated in 1993, and 85 were surveyed in 2001. And the reports of the two groups on respiratory distress, including cough, sputum, phlegm, the notable sound of breathing, nasal discharge, coryza, shortness of breath and gasping, were compared. The findings of this study were as below: 1. The cough report rate was 24.3% in 1993 and 16.5% in 2001. There appeared approximately 7.8% decrease between the two years. The most powerful variables included working hours and age. 2. The complaint rate of sputum and phlegm was 47.1% in 1993 and 43.5% in 2001. The rate of 2001 reduced by 3.6%. Whether or not they smoked was identified as the most influential variable. 3. The report rate of shortness of breath and gasping was 7.4% in 1993 and 12.9% in 2001, and this rate showed about 1.5% increase in the latter year. The biggest variables were working hours and career. 4. The complaint rate of nasal discharge and coryza was 41.4% in 1993 and 44.7% in 2001, which showed about 3.3% increase. The largest variables were smoking and career. 5. The report rate of the notable sound of breathing and breathing in light little gasps was 12.0% in 1993 and 17.6% in 2001. There was approximately 5.6% increase, and the most powerful variables were working hours and career.
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