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In order to determine the effect of twine thickness on the size-selectivity of the driftnet used for the yellow croaker, size-selectivity tests were conducted with three different twine thicknesses (monofilament diameters of 0.279 mm (number’s method; No. 3), 0.321 mm (No. 4), and 0.360 mm (No. 5)) of driftnets for the yellow croaker in the seas around Chooja-do, Jeju Islands. The selectivity curve was estimated by using Kitahara’s method. In order to determine the physical properties of the twine used in the experimental fishing nets, we measured the breaking load, elongation, and stiffness under both dry and wet conditions. In terms of physical properties, the thinnest twine (No. 3) had the strongest breaking strength per unit cross-sectional area, along with good elongation and excellent flexibility. The thickest twine (No. 5) had the lowest flexibility. In terms of selectivity, the net of No. 3 twine showed the broadest selection range and, thus, a relatively low selectivity compared with the other nets, while the less flexible net of No. 5 twine showed the narrowest selectivity range and high selectivity. In addition, it was found that a thicker twine resulted in a smaller haul of small fish. Therefore, it can be inferred that the thickness of the twine affects the size of the catch and selectivity, and thus the size composition of the catch as well.  相似文献   
2.
Kim  Suk Hyun  Ra  Kongtae  Kim  Kyung-Tae  Jeong  Hyeryeong  Lee  Jihyun  Kang  Dong-Jin  Rho  Taekeun  Kim  Intae 《Ocean Science Journal》2019,54(4):673-684
Ocean Science Journal - Trace elements (Mn, Fe, Co, Ni, Cu, Zn, etc.) are essential micronutrients for marine organisms and are thus related to major issues in the ocean, such as climate change,...  相似文献   
3.
This study investigates how physical urban environments affect academic performance of urban public elementary schools in the Philippines by analysing the physical environment of school facilities and slum areas. Global, local, and semi-parametric regression analyses indicate that there is disproportionate provision of resources among the government schools and that lower academic performance is associated with the provision of fewer clinics rather than the proximity to poverty hotspots. Semiparametric, geographically weighted regression modelling outperformed global and local modelling, and estimated up to 30 % of the variation in math scores where the semi-parametric regression model is based on each school’s number of teachers and rooms, building conditions, availability of health clinics, and the location of slum areas near the school. On the basis of the research findings, it is concluded that the current state of school buildings is adequate and is a lower priority than the provision of health care support and smaller pupil–teacher ratios. Hence, government programs that aim to enhance the academic performance of children from the deprived physical urban environments should prioritize the provision of health clinics as well as maintaining few large schools with small pupil–teacher ratios.  相似文献   
4.
Noyes  Chandler  Kim  Jihyun  Person  Mark  Ma  Lin  Ferguson  Grant  McIntosh  Jennifer C. 《Hydrogeology Journal》2021,29(5):1905-1923
Hydrogeology Journal - This study investigates hydraulic connectivity of a stacked aquifer system in the Lisbon Valley of southeastern Utah (USA), within the Paradox Basin, where numerous faults...  相似文献   
5.
Yu  Jihyun  Kang  Min Joo  Kim  Yun Jae  Park  Mi-Jeong  Lim  Jae Kyu  Noh  Choong Hwan  Kang  Sung Gyun  Lee  Hyun Sook  Lee  Jung-Hyun  Kwon  Kae Kyoung 《Ocean Science Journal》2021,56(3):297-306
Ocean Science Journal - The Korean rockfish, Sebastes schlegeli, is most commonly farmed in sea cages along the coast of Korea; however, detailed information on intestinal microbiota regarding this...  相似文献   
6.
In studies of weather changes and, especially, in enhancing the performance of rainfall prediction, it is important to measure the water vapor distribution in the atmosphere. We estimated atmospheric water vapor profiles for fourteen days, including periods of severe weather conditions, by processing ground-based Global Positioning System (GPS) measurements and compared our results with microwave radiometer (MWR) and radiosonde (RAOB) observations. As a result, we found that the standard deviation (STD) of wet refractivity profiles between GPS with MWR was smaller than the STD between RAOB and MWR refractivities; the average STD was 9.3 mm km?1. In particular, we found that GPS-based wet refractivities detected inversion layers close to those from MWR when the observed GPS satellites were well distributed in the azimuth and elevation angle directions. When the satellite geometry was better, the mean error of GPS wet refractivities with respect to MWR was reduced to 0.4 from 3.2 mm km?1 for altitudes lower than 3 km. In some cases, however, the precision of GPS refractivities are lower than that of RAOB ones relative to MWR results.  相似文献   
7.
Chapter 17 of Agenda 21 requires new approaches to marine and coastal area management and development, approaches that are integrated in content and precautionary in ambit. With this understanding, Korea is moving in the direction of a more sustainable society along the general action plans outlined in Agenda 21. This paper describes how Korea has transformed its marine environmental policies at different economic development stages, examines how Korea follows up the UNCED's recommendations, and reviews how various domestic and international strategies for marine and coastal management are being prepared.  相似文献   
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