• Title/Summary/Keyword: Long-term persistence

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An Exploratory Study on the Business Model for Career and Academic Counseling in Non-Urban High Schools (비도시권 고등학교 학생을 위한 진로교육 비즈니스 모형에 관한 탐색적 연구)

  • Park, Seong-Taek;Cho, Min-Woo;Kim, Tae-Ung
    • Journal of Digital Convergence
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    • v.15 no.2
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    • pp.47-58
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    • 2017
  • Career and academic Counseling is often viewed as the catalyst for frequent and consistent interaction with students, but it is more than simply advising students about which majors, universities or jobs to consider. Ongoing, personal contact of career and academic counselors with students is an essential component in long-term career-related efficacy. But statistics show that high schools in non-urban or rural areas face significant issues different from those schools in metropolitan or suburban contexts, failing to maintain the significant number of teachers enough for effective career and academic counseling. This article proposes an alternative model of career and academic counseling, provided by MBA(Master of Business Administration) alumni based social enterprise in Seoul. This service explores the skills, knowledge and capabilities which MBA alumni gained from their jobs and MBA programs within the context of a career-competency framework. This paper concludes with the social and educational aspect of this shared responsibility strategy that may enhance student motivation and persistence in non-urban high schools.

Recent Progress and Tasks of Arms Control in South and North Korea (최근 남북한 군비통제의 추진현황과 과제)

  • Kim, Kang-nyeong
    • Korea and Global Affairs
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    • v.3 no.2
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    • pp.87-130
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    • 2019
  • This paper aims to analyze the recent progress(current situation) and tasks of arms control in North and South Korea. To this end the paper is composed of 5 chapters titled instruction; recent progress(current situation) of arms control in South and North Korea; constraints and tasks of arms control on the Korean peninsula; and conclusion. One of the most important tasks for the establishment of a peace structure for the coexistence of the Korean people in the 21st century is the realization of military control in order to resolve the acute military confrontation situation and mutual threats. With the 2018 PyeongChang Winter Olympics, the North-South summit and the subsequent talks for peace and denuclearization on the Korean Peninsula, the North Korea-US summit, and subsequent talks are creating conditions for trust building and arms control between the two Koreas. The military trust between the two Koreas and operational arms control are being achieved through the declaration of the April 27 Panmunjom and the 'Military Agreement for the Implementation of the Panmunjom Declaration.' However, since there are constraints on the control of arms control, such as the persistence of hostility and distrust of the two Koreas, the defense treaty between the two Koreas and neighboring countries, the competition of neighboring countries and the complex interests of the Korean peninsula, Trust Building is important. We should resolve the issue of arms control between the two Koreas, taking into account the trend of international arms control over the internal and external dynamics of the Korean peninsula gradually and carefully, with a vision of long-term unification security.

Effects of Foreign Plant Extracts on Cell Growth and Biofilm Formation of Streptococcus Mutans (해외 자생식물추출물이 Streptococcus mutans의 세포 성장 및 생물막 형성에 미치는 영향)

  • Moon, Kyung Hoon;Lee, Yun-Chae;Kim, Jeong Nam
    • Journal of Life Science
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    • v.29 no.6
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    • pp.712-723
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    • 2019
  • Chemically synthesized compounds are widely used in oral hygiene products. However, excessively long-term use of these chemicals can cause undesirable side effects such as bacterial tolerance, allergy, and tooth discoloration. To solve these issues, significant effort is put into the search for natural antibacterial agents. The aim of this study was to assess the extracts of foreign native plants that inhibit the growth and biofilm formation of Streptococcus mutans. Among the 300 foreign plant extracts used in this study, Chesneya nubigena (D. Don) Ali extract had the highest antimicrobial activity relatively against S. mutans with a clear zone of 9 mm when compared to others. This plant extract also showed anti-biofilm activity and bacteriostatic effect (minimal bactericidal concentration [MBC], 1.5 mg/ml). In addition, the plant extracts of 19 species decreased the ability of S. mutans to form biofilm at least a 6-fold in proportion to the tested concentrations. Of particular note, C. nubigena (D. Don) Ali extract was found to inhibit biofilm formation at the lowest concentration tested effectively. Therefore, our results reveal that C. nubigena (D. Don) Ali extract is a potential candidate for the development of antimicrobial substitutes, which might be effective for caries control as well, as demonstrated by its inhibitory effect on the persistence and pathogenesis of S. mutans.

Internal Dynamics of Wetland Specialist, Population of Lychnis wilfordii (Regel) Maxim. (습지 전문종인 제비동자꽃(Lychnis wilfordii (Regel) Maxim.) 개체군의 내적동태)

  • Chae, Hyun-Hee;Kim, Young-Chul;Kwak, Myoung-Hai;Nam, Gi-Heum
    • Korean Journal of Environment and Ecology
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    • v.35 no.3
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    • pp.237-255
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    • 2021
  • Lychnis wilfordii (Regel) Maxim. is one of the wetland specialists mainly distributed in peatlands at high latitudes. In Korea, it is isolated in two regions. This study investigated habitats, growth traits, and self-compatibility of L. wilfordii and assessed the internal dynamics of its population persistence. Its population has remained stable in the Yongneup Wetland Protected Area (YWPA). There was a clear difference in vegetation environment between YWPA and the distribution area in Daegwallyeong (DWL), Pyeongchang-gun. It has self-compatibility while pollinators facilitate its seed production. It produces a large number of hibernacles and bears the maximum number of branches and fruits in soil with rich organic contents. However, it grows and bears fruits even under the condition of low organic contents. In YWPA, L. wilfordii is not distributed in high moor but widely distributed in low moor where tussocks by Carex thunbergii var. appendiculata are developed. It is mainly distributed on the top of tussocks also. Therefore, it is judged that the formation, growth, and extinction of tussocks by C. thunbergii var. appendiculata is closely related to the establishment, growth, and extinction of plants distributed in this space. It is assessed that the current YWPA has well-developed tussocks in which L. wilfordii is widely distributed, and extinction and re-establishment progress well. Accordingly, the L. wilfordii population is expected to be sustainable in the long term given if its current ecological process is maintained well.

Changes in Fermentation Characteristics and Microbial Community According to Microbial Additives and Storage Periods on Corn Silage (옥수수 사일리지에서 미생물 첨가제와 저장기간이 발효 품질과 미생물 군집에 미치는 영향)

  • Seung Min Jeong;Hyung Soo Park;Jae Hoon Woo;Ji Hye Kim;Dong Hyun Kim;Bo Ram Choi;Mirae Oh
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.44 no.2
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    • pp.113-117
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    • 2024
  • This study was conducted to find a way to improve quality by observing changes in quality and microbial communities according to whether corn silage was treated with additives and the storage period, and to utilize them as basic research results. The experimental design was performed by 2×4 factor desigh, and the untreated (CON), and the additive inoculated (ADD) silage were stored and fermented for 30 (TH), 60 (ST), 90 (NT), and 120 (OHT) days, with each condition repeated 3 times. There was no change in the nutrient content of corn silage according to additive treatment and storage period (p>0.05). However, the change in DM and the increase in the relative proportions of lactic acid content and Lactobacillales according to the storage period (p<0.05) indicate that continuous fermentation progressed until OHT days of fermentation. Enterobacterales (33.0%), Flavobacteriales (14.4%), Sphingobacteriales (12.7%), Burkholderiales (9.28%) and Pseudomonadales (6.18%) dominated before fermentation of corn silage, but after fermentation, the diversity of microorganisms decreased sharply due to the dominance of Lactobacillales (69.4%) and Bacillales (11.5%), Eubacteriales (7.59%). Therefore, silage maintained good fermentation quality with or without microbial additives throughout all fermentation periods, but considering the persistence of fermentation even in long-term storage and the aerobic stability, it would be advantageous to use microbial additives.

A Study on the Volatility of Global Stock Markets using Markov Regime Switching model (마코브국면전환모형을 이용한 글로벌 주식시장의 변동성에 대한 연구)

  • Lee, Kyung-Hee;Kim, Kyung-Soo
    • Management & Information Systems Review
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    • v.34 no.3
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    • pp.17-39
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    • 2015
  • This study examined the structural changes and volatility in the global stock markets using a Markov Regime Switching ARCH model developed by the Hamilton and Susmel (1994). Firstly, the US, Italy and Ireland showed that variance in the high volatility regime was more than five times that in the low volatility, while Korea, Russia, India, and Greece exhibited that variance in the high volatility regime was increased more than eight times that in the low. On average, a jump from regime 1 to regime 2 implied roughly three times increased in risk, while the risk during regime 3 was up to almost thirteen times than during regime 1 over the study period. And Korea, the US, India, Italy showed ARCH(1) and ARCH(2) effects, leverage and asymmetric effects. Secondly, 278 days were estimated in the persistence of low volatility regime, indicating that the mean transition probability between volatilities exhibited the highest long-term persistence in Korea. Thirdly, the coefficients appeared to be unstable structural changes and volatility for the stock markets in Chow tests during the Asian, Global and European financial crisis. In addition, 1-Step prediction error tests showed that stock markets were unstable during the Asian crisis of 1997-1998 except for Russia, and the Global crisis of 2007-2008 except for Korea and the European crisis of 2010-2011 except for Korea, the US, Russia and India. N-Step tests exhibited that most of stock markets were unstable during the Asian and Global crisis. There was little change in the Asian crisis in CUSUM tests, while stock markets were stable until the late 2000s except for some countries. Also there were stable and unstable stock markets mixed across countries in CUSUMSQ test during the crises. Fourthly, I confirmed a close relevance of the volatility between Korea and other countries in the stock markets through the likelihood ratio tests. Accordingly, I have identified the episode or events that generated the high volatility in the stock markets for the financial crisis, and for all seven stock markets the significant switch between the volatility regimes implied a considerable change in the market risk. It appeared that the high stock market volatility was related with business recession at the beginning in 1990s. By closely examining the history of political and economical events in the global countries, I found that the results of Lamoureux and Lastrapes (1990) were consistent with those of this paper, indicating there were the structural changes and volatility during the crises and specificly every high volatility regime in SWARCH-L(3,2) student t-model was accompanied by some important policy changes or financial crises in countries or other critical events in the international economy. The sophisticated nonlinear models are needed to further analysis.

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Replacement of Saline Water through Injecting Fresh Water into a Confined Saline Aquifer at the Nakdong River Delta Area (염수로 충진된 낙동강 델타지역 피압대수층에서 담수주입에 의한 염수치환 연구)

  • Won, Kyung-Sik;Chung, Sang Yong;Lee, Chang-Sup;Jeong, Jae-Hoon
    • The Journal of Engineering Geology
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    • v.25 no.2
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    • pp.215-225
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    • 2015
  • We performed injection tests in a deep-seated confined aquifer to assess the potential of artificial recharge as a means of preventing saltwater contamination, thereby securing groundwater resources for the Nakdong Delta area of Busan City, Korea. The study area comprises a confined aquifer, in which a 10-21-m-thick clay layer overlies 31.5-36.5 m of sand and a 2.8-11-m-thick layer of gravel. EC logging of five monitoring wells yielded a value of 7-44 mS/cm, with the transition between saline and fresh water occurring at a depth of 15-38 m. Above 5 m depth, water temperature is 10-15.5℃, whereas between 5 and 50 m depth the temperature is 15.5-17℃. Approximately 950 m3 of fresh water was injected into the OW-5 injection well at a rate of 370 m3/day for 62 hours, after which the fresh water zone was detected by a CTD Diver installed at a depth of 40 m. The persistence of the fresh water zone was determined via EC and temperature logging at 24 hours after injection, and again 21 days after injection. We observed a second fresh water zone in the OW-2 well, where the first injection test was performed more than 20 days before the second injection test. The contact between fresh and saline water in the injection well is represented by a sharp boundary rather than a transitional boundary. We conclude that the injected fresh water occupied a specific space and served to maintain the original water quality throughout the observation period. Moreover, we suggest that artificial recharge via long-term injection could help secure a new alternative water resource in this saline coastal aquifer.

Long Term Effects of Lamivudine and Adefovir dipivoxil in Chronic Hepatitis B Patients on the Development of Hepatocellular Carcinoma (만성 B형간질환에서 HBV백신 및 항바이러스치료가 간세포암종 발생에 미치는 효과)

  • Lee, Heon-Ju
    • Journal of Yeungnam Medical Science
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    • v.25 no.1
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    • pp.1-18
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    • 2008
  • Although Lamivudine and adefovir dipivoxil are efficacious drugs for preventing hepatocellular carcinoma (HCC) in chronic hepatitis B patients, their efficacy is far from completely satisfactory. The risk of liver cirrhosis and HCC begins to increase at an HBV DNA level of $10^4$ copies/ml. Even with latent or past HBV infection, episomal covalently closed circular DNA(cccDNA) plays a key rolein the persistence, relapse and resistance of HBV in its natural course or during therapy. The annual incidence of HCC in YUMC is 1.8% and 4.7% patients/year in the antiviral treatment and control groups, respectively. The ability to achieve a high rate of sustained HBV suppression with low risk of drug resistance is the ultimate goal in the treatment of chronic HBV infection. The efficacy of universal immunization with striking reductions in the prevalence of HBV in localized countries needs to be spread worldwide. With hepatitis B immunization and effective antiviral therapy, global control of HBV infection and HBV-related complications, including HCC, are possible by the end of the first half of the $21^{st}$ century.

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Four-year change and tracking of serum lipids in Korean adolescents (강화지역 청소년의 4년간 혈청 지질의 변화와 지속성)

  • Lee, Kang-Hee;Suh, Il;Jee, Sun-Ha;Nam, Chung-Mo;Kim, Sung-Soon;Shim, Won-Heum;Ha, Jong-Won;Kim, Suk-Il;Kang, Hyung-Gon
    • Journal of Preventive Medicine and Public Health
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    • v.30 no.1 s.56
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    • pp.45-59
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    • 1997
  • It has been known that there is a tracking phenomenon in the level of serum lipids. However, no study has been performed to examine the change and tracking of serum lipids in Korean adolescents. The purpose of this study is to examine the changes of serum lipids in Korean adolescents from 12 to 16 years of age, and to examine whether or not there is a tracking phenomenon in serum lipids level during the period. In 1992 serum lipids(total cholesterol(TC), triglyceride(TG), LDL cholesterol(LDL-C), HDL cholesterol(HDL-C)) were measured in 318 males, 365 females who were 12 years of age in Kangwha county, Korea. These participants have been followed up to 1996 and serum lipids level were examined in 1994 and 1996. Among the participants 162 males and 147 females completed all three examinations in fasting state. To examine the effect of eliminating adolescents with incomplete data, we compared serum lipids, blood pressure and anthropometric measures at baseline between adolescents with complete follow-up and adolescents who were withdrawn. To examine the change of serum lipids we compared mean values of serum lipids according to age in males and females. Repeated analysis of variance was used to test the change according to age. We used three methods to examine the existence of tracking. First, we analyzed the trends in serum lipids over 4-year period within quartile groups formed on the basis of the first-year serum lipids level to see whether or not the relative ranking of the mean serum lipids among the quartile groups remained in the same group for 4-year period. Second, we quantified the degree of tracking by calculating Spearman's rank correlation coefficient between every tests. Third, the persistence extreme quartile method was used. This method divides the population into quartile groups according to the initial level of blood lipids and then calculates the percent of the subjects who stayed in the same group at follow-up measurement. The decreases in levels were noted during 4 years for TC, LDL-C, primarily for boys. The level of HDL-C decreased between baseline and first follow-up for both sexes. Tracking, as measured by both correlation coefficients and persistence extreme quartiles, was evident for all of the lipids. The correlation coefficients of TC between baseline and 4 years later in boys and girls were 0.55 and 0.68, respectively. And the corresponding values for HDL-C were 0.58 and 0.69. More than 50% of adolescents who belonged to the highest quartile group in TC, HDL-C and LDL-C at the baseline were remained at the same group at the examination performed 2 years later for both sexes. The probabilities of remaining at the same group were more than 35% when examined 4 years later. The tracking phenomenon of TG was less evident compared with the other lipids. Percents of girls who stayed at the same group 2 years later and 4 years later were 42.9% and 25.7%, respectively. It was evident that serum lipid levels tracked in Korean adolescents. Researches with longer follow-up would be needed in the future to investigate the long-term change of lipids from adolescents to adults.

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