• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.205-215
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• 2009

In order to understand on the seasonal dynamics of phytoplankton in the mouth parts of Gamak Bay, Korea, we investigated from one station during June 2005 to June 2006. Samples were collected every week during the high water temperature (${\geq}20^{\circ}C$), and every two weeks during the low water temperature (${\leq}20^{\circ}C$). The phytoplankton community were composed of 76 genera, 208 species in the surface layer, and 72 genera, 186 species in the bottom layer (total: 77 genera, 214 species). The number of occurring species fluctuated greatly throughout the year from 27 species (March 15, 2006) to 121 species (Aug. 16, 2005). High number of species showed between June and September (>70 species), whereas the low number of species showed during the period of the low water temperature below $20^{\circ}C$ (ca. 40 species). The predominant species were diatom Skeletonema costatum during whole year, and two naked dinoflagellates, Cochlodinium polykrikoides and Polykrikos kofoidii during high temperature seasons. However, centric diatoms, Chaetoceros curvisetus, Chaetoceros debilis and Eucampia zodiacus were dominant species during low temperature seasons. Standing crops of dinoflagellate showed great fluctuations, which were ranged from $3.0{\times}10^5\;cells\;L^{-1}$ (April 17, 2006) to $7.3{\times}10^5\;cells\;L^{-1}$ (Aug. 2, 2005) in the surface layer and from $1.5{\times}10^3\;cells\;L^{-1}$ (Nov. 9, 2005) to $3.9{\times}10^5\;cells\;L^{-1}$ (Aug. 16, 2005) in the bottom layer, and showed high during high temperature seasons such as the number of species. The fluctuations were greater in the surface layer than in the bottom layer. Moreover, the variation of Cochlodinium polykrikoides, is affected by Polykrikos kofoidii grazing.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.345-356
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• 2012

We investigated the changes of fruit quality parameters, polysaccharide contents and cell wall components during maturation and ripening of two Korean pear cultivar 'Hanareum' and 'Manpungbae' compared with 'Niitaka' pear (Pyrus pyrifolia Nakai) which showed different physiological maturity based on days after full bloom (DAFB). Flesh firmness decreased continuously with fruit development and maturation, reaching a final level of 29.4, 33.5, and 27.4N at maturity in 'Hanareum' (127 DAFB), 'Manpungbae' (163 DAFB), and 'Niitaka' (170 DAFB), respectively. The level of ethylene production was very low in early season 'Hanareum' pear which showed at most 0.39 ${\mu}L{\cdot}L^{-1}$ at maturity and no ethylene was detected in 'Manpungbae' and 'Niitaka' at maturity. Fructose was the most abundant soluble sugar during fruit maturation in the pears tested and an increase of sucrose was observed during fruit ripening in the Asian pears commonly. Ethanol insoluble solids (EIS) content decreased gradually with different levels among the pear cultivars as fruit ripens consisted of 10.79, 12.72, and 12.75 $mg{\cdot}g^{-1}$ FW. The amount of total soluble polyuronides was higher in early season cultivars 'Hanareum' than those of mid-season cultivar 'Manpungbae' and 'Niitaka'. In 'Niitaka' which harvested most late season, the level of 4% KOH soluble hemicelluloses was lower than 'Hanareum' and 'Manpungbae' and maintained constantly during fruit ripening period. Cellulosic residues were determined high level in 'Niitaka' which showed 612.33 ${\mu}g{\cdot}mg^{-1}$ EIS at maturity when compared with 'Hanareum' (408.0 ${\mu}g{\cdot}mg^{-1}$ EIS) and 'Manpungbae' (538.67 ${\mu}g{\cdot}mg^{-1}$ EIS). The main constituents of cell wall neutral sugars which consisted of arabinose, xylose, galactose, and glucose were decreased gradually with onset of fruit ripening regardless of cultivar. Arabinose which was predominant in 'Hanareum' pear decreased at the last stage of ripening, but the changes of cell wall neutral sugar during ripening were not occurred in 'Niitaka' pear. The change of molecular mass distribution in water soluble pectin observed dominantly at the early stage of fruit development. Depolymerization of 4% KOH-soluble hemicelluloses and degradation of xyloglucan showed in early-season cultivar 'Hanareum' during fruit maturation, and degradation of those fractions were detected only at the early stage fruit development in mid-season cultivar 'Manpungbae' and 'Niitaka'. The molecular mass profile of CDTA soluble pectin, $Na_2CO_3$-SP and 24% KOH soluble hemicelluloses showed no significant change during fruit maturation regardless of cultivar.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.563-579
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• 2016

This study seeks educational implication by analyzing research papers dealing with science assessment in the most recent 30 years in Korea. The main purpose of the study is to analyze the trends in published papers on science assessment, their purpose, methodology, and key words, especially concentrating on the cognitive and affective domains. We selected 273 research articles and categorized them by research object, subject, methodology, and contents. To examine the factors that affect the research trend, we also tried to contextualize papers' theme in terms of changes in national curriculum and assessment system during the contemporary period. As a result, an overall research trend reflects changes in science curriculum and assessment events such as implementation of college scholastic ability test or performance assessment. There is an unequal distribution in various aspects of the researches, showing a superiority in cognitive domains than the affective ones. By using standardized data obtained through the national and international assessment of educational achievement in science, quantitative researches were superior to qualitative ones. Studies on cognitive domain use variously written- and performance-based tests, whereas most studies of the affective ones prefer written tests. Applied research and evaluation research are predominant comparing to basic ones, which most of the research methodology is based on statistics. Lastly, we found out that key words and subjects tend to be subdivided and detailed rather than general and comprehensive, as time goes on. Such trend will be helpful to elaborate and refine assessment tools that have been regarded as a problem.

• Korea journal of population studies
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• v.29 no.1
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• pp.185-207
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• 2006

Predominant explanations of the persistence of sex segregation ill occupations link job choices to profoundly gendered responses to childbearing and other family demands, arguing that women are more likely to seek jobs which are in some sense compatible with motherhood, either because they are family friendly (flexible, low intensity work) or because they are easy to exit and re-enter. In this paper, I examine the effect of occupational sex segregation on job exits into the labor market among women, with a special attention to the role of childbearing and child rearing. I use data from detailed employment histories gathered from the National Longitudinal Survey of Youth (NLSY) in continuous time event history models. My results indicate that women in female dominated jobs are less likely to exit their jobs than women in other types of occupations. Further this relationship is not shaped by motherhood. While mothers or pregnant women are more likely to leave work, mothers in female-dominated occupations are slightly less likely to leave employment than mothers in other occupations. These results are not consistent with the ideas that women's choice of female-dominated occupations expresses a gendered identity and women strategically seek jobs which accommodate maternal roles. Taken together, my findings do not provide support to the idea that women choose female-dominated occupations because they are easier to integrate with motherhood (except for the pregnancy period).

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.44-52
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• 2011

Purpose: Cytogenetic analysis of spontaneous abortions (SABs) provides valuable information to establish the causes of fetal loss, information that is essential to provide accurate reproductive and genetic counseling couples. Such analysis also provides information on the frequencies and types of chromosomal abnormalities and associated risks of recurrence. However, there have only been a few reports of chromosomal abnormalities in small samples of SABs in the Korean population. Here, we report the incidence and spectrum of chromosomal abnormalities for cases of 470 SAB in Korea. Material and Methods: Between 2005 and 2010, a total of 470 products of conception (POC) resulting from SABs were submitted to our laboratory for cytogenetic analysis from various medical sites in Korea. The incidences and types of specific chromosomal abnormalities were determined. The abnormalities were distinguished by gestational age at the time of SAB and by maternal age. Results: The frequency of chromosomal abnormalities in POCs was 54.3% (255/470), including 228 (89.3%) numerical and 27 (10.7%: 3 balanced and 24 unbalanced) structural abnormalities. Among the numerical abnormalities, trisomy was predominant (67.0%), followed by monosomy X (12.5%), polyploidy (8.2%), triple X (0.8%), and autosomal monosomy (0.8%). The overall sex ratio (male: female) among the 470 POCs with normal and abnormal karyotypes were 0.58 and 0.65, respectively. Trisomies were identified for each autosome, with the exceptions of 1, 3, and 19. Among the 171 autosomal trisomies, trisomy 16 was the most common (19.9%), followed by trisomy 22 (13.5%), trisomy 21 (12.3 %), trisomy 15 (9.9%), and trisomies 18 and 13 (5.3%). The frequency of chromosomal abnormalities decreased with gestational age and increased with maternal age, but only because of increases in trisomies and complex abnormalities. Conclusions: We have presented a large collection of cytogenetic data for SABs collected during the past 6 years and provided a database for prenatal genetic counseling of parents who have experienced SABs in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.3
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• pp.345-356
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• 1996

Properties of enzymatic hydrolysates from ascidian tunic were assessed on supernatant ratio, solid yields and solid concentration. The concentartion of solid and yields in the extracts were increased as the enzyme concentration raised from $100\;{\mu}l\;to\;1000{\mu}l$ during the extraction period. The optima concentration and reaction time of each enzyme on digestion were $400\;{\mu}l$ 60 minutes, through treated with Duncan's multiple test. The percent of yields of solid, protein and carotenoids for 60 minutes extraction at $400\;{\mu}l$ were $32.32\%,\;1.34\%\;and\;74.60\;mg\%$, respectively, in Viscozyme systems. The extracts were composed with many kinds of carbohydrates such as arabinose, ribose, xylose, galactose, glucose, N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine. Aspartic and glutamic arid were noted as predominant amino acids in all parts. Amino acid profiles of various ascidian tunic part were similiar to each other, but most of essential amino acids content of inter coat was higher than that of root and tunic (body). About sixty six fatty acids components were observed, and their distribution among neutral and polar lipids was compared. The main fatty acids were found to be 14:0, 16:0, 16:1n7, 18:0, 18:1n9, 18:1n7, 18:2n6, 20:5n3, and 22:6n3.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1835-1842
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• 2014

Various microorganisms are involved in the fermentation of Mageoli, Korean traditional liquor. Among them, the most predominant microorganism is yeast, including Saccharomyces cerevisae. This study investigated the effects of crude polysaccharides separated from Mageoli mash (CP-M) on activation of peritoneal macrophages in cell culture medium. Four types of yeasts, S. cerevisae 89-1-1, 98-2, 268-3, and 113-4, were used. When peritoneal macrophages were treated with $10{\mu}g/mL$ of CP-M fermented with S. cerevisae 113-4, the concentration of nitric oxide (NO) in the medium was highest ($33.3{\mu}M$). The concentrations of IL-6 and -12 were also highest at 116.3 pg/mL and 59.8 pg/mL, respectively. In the case of CP-M cultured at 15, 20, and $30^{\circ}C$ after inoculation with S. cerevisae 113-4 and fermented at different temperatures, production of NO and IL-6 by peritoneal macrophages did not change compared to the control. For CP-M obtained after fermentation at $25^{\circ}C$, however, NO concentration increased 2.7~3.3 fold and IL-6 concentration by 5.7 fold compared to the control. Furthermore, the effect of fermentation period on expression of CP-M functionality was examined. NO production by CP-M of the 5th day mash was highest, increasing 2.2 fold compared to 0-day CP-M. However, there were no significant differences in concentration of IL-6 or -12 according to different fermentation periods, although CP-M showed a large decrease after 10 days. The results show that fermentation conditions with the highest activity were observed in CP-M inoculated with S. cerevisae 113-4 and fermented at $25^{\circ}C$ for 5 days. CP-M consisted of 78.6% neutral sugar, 11.6% acidic polysaccharide, and 9.8% protein. In particular, the sugar composition of neutral sugar consisted of mannose (47.8%), glucose (29.6%), and galactose (12.7%). Based on the results, CP-M is assumed to be an extracellular polysaccharide originating in yeast with high mannose content.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.206-214
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• 2005

Heterogeneously-catalyzed oxidation of aqueous phase trichloroethylene (TCE) over supported metal oxides has been conducted to establish an approach to eliminate ppm levels of organic compounds in water. A continuous flow reactor system was designed to effect predominant reaction parameters in determining catalytic activity of the catalysts for wet TCE decomposition as a model reaction. 5 wt.% $CoO_x/TiO_2$ catalyst exhibited a transient period in activity vs. on-stream time behavior, suggesting that the surface structure of the $CoO_x$ might be altered with on-stream hours; regardless, it is probable to be the most promising catalyst. Not only could the bare support be inactive for the wet decomposition reaction at $36^{\circ}C$, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Very low TCE conversion appeared for $TiO_2$-supported $NiO_x$ and $CrO_x$ catalysts. Wet oxidation performance of supported Cu and Fe catalysts, obtained through an incipient wetness and ion exchange technique, was dependent primarily on the kinds of the metal oxides, in addition to the acidic solid supports and the preparation routes. 5 wt.% $FeO_x/TiO_2$ catalyst gave no activity in the oxidation reaction at $36^{\circ}C$, while 1.2 wt.% Fe-MFI was active for the wet decomposition depending on time on-stream. The noticeable difference in activity of the both catalysts suggests that the Fe oxidation states involved to catalytic redox cycle during the course of reaction play a significant role in catalyzing the wet decomposition as well as in maintaining the time on-stream activity. Based on the results of different $CoO_x$ loadings and reaction temperatures for the decomposition reaction at $36^{\circ}C$ with $CoO_x/TiO_2$, the catalyst possessed an optimal $CoO_x$ amount at which higher reaction temperatures facilitated the catalytic TCE conversion. Small amounts of the active ingredient could be dissolved by acidic leaching but such a process gave no appreciable activity loss of the $CoO_x$ catalyst.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.275-287
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• 2013

The Japanese anchovy Engraulis japonicus is a widespread species in the western North Pacific and major fishery resource. To understand the spatio-temporal variation of anchovy prey items in the coastal waters of southern Korea, the stomach contents of anchovy and the structure of the zooplankton community were analysed at three sites (Jindo, Yeosu and Tong-yeong) from July 2011 to February 2012. The main prey items in Yeosu and Jindo were cyprid stage of barnacle (>35%) and copepod Calanus sinicus (>22%) in July, respectively, while, predominant ones in Tongyeong were small copepods, Paracalanus parvus s.l. (41%) and Corycaeus affinis (22%). During this period, the dominant zooplankton were cladoceran Evadne tergestina (39%) in Yeosu, small copepod, P. parvus s.l. (28%) in Jindo and cladoceran E. tergestina (14%) in Tongyeong. The dominant prey items were barnacle larvae and copepods in summer, phytoplankton and Pseudodiaptomus marinus in autumn and P. parvus s.l. and cold water copepod, Centropages abdominalis in winter. Anchovy prefer the prey item C. sinicus (3%) over E. tergestina (39%), which was a dominant species in the catching site in summer. P. marinus (0.5%) and C. abdominalis (0.9%) were preferred over P. parvus s.l. (30%, 21%) in autumn and winter, respectively. Prey items varied with area and season in the coastal waters of southern Korea. These results suggest that the prey selectivity of anchovy showed high flexibility and adaptability in the study waters.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.2
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• pp.69-84
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• 1984

This study was carried out to investigate the time distribution of single storms and to establish the model of storm patterns in korea. Rainfall recording charts collected from 42 metheorological stations covering the Korean peninsula were analyzed. A single storm was defined as a rain period seperated from preceding and succeeding rainfall by 6 hours and more. Among the defined single storms, 1199 storms exceeding total rainfall of 80 mm were qualified for the study. Storm patterns were cklassified by quartile classification method and the relationship between cummulative percent of rainfalls and cummulative storm time was established for each quartile storm group. Time distribution models for each stations were prepared through the various analytical and inferential procedures. Obtained results are summarized as follows: 1. The percentile frequency of quartile storms for the first to the fourth quartile were 22.0%, 26.5%, 28.9% and 22.6%, respectively. The large variation of percentile frequency was show between the same quartile storms. The advanced type storm pattern was predominant in the west coastal type storm patterns predominantly when compared to the single storms with small total rainfalls. 3. The single storms with long storm durations tended to show delayed type storm patterns predominantly when compared to the single storms with short storm durations. 4. The percentile time distribution of quartile storms for 42 rin gaging stations was estimated. Large variations were observed between the percentiles of time distributions of different stations. 5. No significant differences were generally found between the time distribution of rainfalls with greater total rainfall and with less total rainfall. This fact suggests that the size of the total rainfall of single storms was not the main factor affecting the time distribution of heavy storms. 6. Also, no significant difference were found between the time distribution of rainfalls with long duration and with short duration. The fact indicates that the storm duration was no the main factor affecting the time distribution of heavy storms. 7. In Korea, among all single storms, 39.0% show 80 to 100mm of total rainfall which stands for the mode of the frequency distribution of total rainfalls. The median value of rainfalls for all single storms from the 42 stations was 108mm. The shape of the frequency distribution of total rainfalls showed right skewed features. No significant differences were shown in the shape of distribution histograms for total rainfall of quartile storms. The mode of rainfalls for the advanced type quartile storms was 80~100mm and their frequencies were 39~43% for respective quartiles. For the delayed type quartile storms, the mode was 80~100mm and their frequencies were 36!38%. 8. In Korea, 29% of all single storms show 720 to 1080 minutes of storm durations which was the highest frequency in the frequency distribution of storm durations. The median of the storm duration for all single storms form 42 stations was 1026 minutes. The shape of the frequency distribution was right skewed feature. For the advanced type storms, the higher frequency of occurrence was shown by the single storms with short durations, whereas for the delayed type quartile storms, the higher frequency was shown gy the long duration single storms. 9. The total rainfall of single storms was positively correlated to storm durations in all the stations throughout the nation. This fact was also true for most of the quartile storms. 10. The third order polynomial regression models were established for estimating the time distribution of quartile storms at different stations. The model test by relative error method resulted good agreements between estimated and observed values with the relative error of less than 0.10 in average.