• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.198-204
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• 1994

Many old books concerning agriculture in ancient Korea were published during Yi dynasty, giving information on the agriculture of old and recent times, Present work describes the introduction of tobacco to Korea by reviewing old domestic or foreign agricultural literatures dealing with names of tobacco. Historically, tobacco had been called as many names such as Namcho, Yeoncho, Au, Seocho, Oecho, Hocho, Dampa Ko, Namkyongcho and Dampacke, and known to be introduced to Korea during early part of Kwanghwekun rule (year of 1618) from Japan. However, tobacco introduction from Japan to Korea seemed not be true by 2 historical facts. One is that at old time Japan had imported Chinese and Korean culture, and many crops during Nara and Heyan dynasties. The other is that there is no evidence of Japanese introduction found in Japan nowadays. The most plausible theory on tobacco introduction is that soldiers under General Youjung of Myong dynasty had brought tobacco to Korea during ImJinWaeRan(1592-1598). The above statements can be verified by old stories about Korean local tobacco varieties, and by letters Kim Dae Hyun(1553-1602) and General Youjoung.

• Perspectives in Nursing Science
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• v.15 no.2
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• pp.92-106
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• 2018

Purpose: The purpose of this study was to review health-related interventions in nursing studies for low-income school-age children and adolescents. Methods: Searches among CINAHL, MEDLINE, PubMed, EMBASE, DBpia, and RISS identified 27 intervention studies published from January 2000 to April 2018. Results: Twenty-seven intervention studies were identified: 12 included psychosocial adaptations and 15 included the healthy lifestyle promotion and disease prevention. The settings were mainly schools and community welfare centers. Many studies were based on social cognitive theory and interventions were provided in a group format. Depression, self-esteem, resilience, self-efficacy for vegetable and fruit consumption, physical activity, and health-related knowledge improved significantly after the health-related interventions. However, the findings were inconsistent with regard to anxiety, peer relationships, body mass index (BMI), blood pressure, cholesterol, and glucose. Conclusion: There is potential for enhancing outcomes for psychosocial, physical health, and health-related knowledge among low-income school-age children and adolescents. Integrated interventions addressing the physical as well as psychological health of low-income children and adolescents should be conducted. It would be prudent to consider the ethnicity and family background of the child or adolescent. However, rigorous study designs and scientific validation are needed for further evidence.

• Journal of the Korean earth science society
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• v.29 no.1
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• pp.91-97
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• 2008

The purpose of this study is to explore high school students' understanding of the distinction between scientific theories and scientific laws. Understanding of the distinction between these two concepts, which belong to the nature of science, has been receiving little attention. We surveyed thirty-two students from a local high school with three-part, open-ended questionnaire. The result revealed that these students shared common misconceptions such as 'scientific theories are unproven, scientific laws are proven and absolute', and 'if a theory is proven with enough evidence, it becomes a law'. Moreover, students tend to regard earth science less sophisticated than physical science, because they recognize a lot of its theories to be unproven in their view. It is indicated further that teaching the difference between scientific theories and laws explicitly could help students possess more appropriate view toward earth science.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.44-52
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• 1997

Nephrolithiasis is the most common disorder of the urinary tract in hospitalized patients, more frequently increased in 30~50 years of age, more common in males than in females, prior right stone to left side, and than upper ureteral stone is found in cultural country, while lower ureteral stone is increased in uncultural country. Stone components are classified as calcium oxalate, calcium phosphate, magnesium ammonium phosphate, uric acid, cystine, and their mixed stone, respectively. According to the pathophysiology of urinary stones, supersaturation/crystalization of inorganic salt concentration in urine, organic matrix, inhibitor deficiency, and epitaxy theory could be based on the stone formation. Not only hypercalciuria, hyperparathyroidism, hyperoxaluria, hyperuricosuria, and cystinuria, but also renal tubular acidosis, hypervitaminosis D, and peptic ulcer, are significantly associated with nephrolithiasis. In this study upper ureteral stone component were analyzed with chemical analysis, infrared spectrum, and image analyzer from K43 patient wit erosive gastritis. As the results, mixed stone of calcium oxalate dihydrate and calcium phosphate apatite was identified, the values of clinical test in blood and urine maintained normal revels. The relapsing urinary stone from K43 have no correlation between factors for stone formation reported early, also have no evidence for risk from erosive gastritis.

• Sleep Medicine and Psychophysiology
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• v.28 no.1
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• pp.18-26
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• 2021

Sleep is essential to brain function and mental health. Insomnia and obstructive sleep apnea (OSA) are the two most common sleep disorders, and are major public health concerns. Proton magnetic resonance spectroscopy (¹H-MRS) is a non-invasive method of quantifying neurometabolite concentrations. Therefore, ¹H-MRS studies on individuals with sleep disorders may enhance our understanding of the pathophysiology of these disorders. In this article, we reviewed ¹H-MRS studies in insomnia and OSA that reported changes in neurometabolite concentrations. Previous studies have consistently reported insomnia-related reductions in γ-aminobutyric acid (GABA) levels in the frontal and occipital regions, which suggest that changes in GABA are important to the etiology of insomnia. These results may support the hyperarousal theory that insomnia is associated with increased cognitive and physiological arousal. In addition, the severity of insomnia was associated with low glutamate and glutamine levels. Previous studies of OSA have consistently reported reduced N-acetylaspartate (NAA) levels in the frontal, parieto-occipital, and temporal regions. In addition, OSA was associated with increased myo-inositol levels. These results may provide evidence that intermittent hypoxia induced by OSA may result in neuronal damage in the brain, which can be related to neurocognitive dysfunction in patients with OSA. The current review summarizes findings related to neurochemical changes in insomnia and OSA. Future well-designed studies using ¹H-MRS have the potential to enhance our understanding of the pathophysiology of sleep disorders including insomnia and OSA.

• Journal of Korean Library and Information Science Society
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• v.53 no.2
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• pp.333-353
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• 2022

This study analyzed the relevance of the curriculum by applying topic modeling to book reports written as content area reading activities in the 'physics' class. In order to carry out the research, 332 physics book reports were collected to analyze the relevance among keywords and topics were extracted using STM. The result of the analysis showed that the main keywords of the physics book reports were 'thought', 'content', 'explain', 'theory', 'person', 'understanding'. To examine the influence and connection relationship of the derived keywords, the study presented degree centrality, between centrality, and eigenvetor centrality. As a result of the topic modeling analysis, eleven topics related to the physics curriculum were extracted, and the curriculum linkage could be drawn in three subjects (Physics I, Physics II, Science History), and six areas (force and motion, modern physics, wave, heat and energy, Western science history, and What is science). The analyzed results can be used as evidence for a more systematic implementation of content area reading activities which reflect the subject characteristics in the future.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2003.05a
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• pp.31-43
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• 2003

The transformation of sector system in ICT, a prominent character in sector systems, has been paid much attention in innovation theory since Information technologies and technological environment have rapidly changed. In this context, we employ US patent data and proxy variables, measuring the basic elements for analyzing SIS and its technological characteristics in order to explore how SIS is transformed. By utilizing patent analysis, it is demonstrated that technological regimes, key links and Schumpeterian patterns of innovation have transformed drastically over last 3 decades in overall ICT sector. Consequently, our research shows clear evidence that Schumpeterian patterns of innovation have shifted from Mark I to Mark II in ICT. Our study provides a glimpse picture of dynamics of SIS since 1970 in the technological level by utilizing patent analysis.

• Environmental and Resource Economics Review
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• v.26 no.4
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• pp.499-517
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• 2017

The purpose of this article is to show profit margin hedging can be an optimal strategy in crude oil purchasing. This study theoretically analyzes profit margin hedging strategy is optimal in crude oil purchasing using expected target utility function and conducts simulations to show if the profit margin hedging is profitable. In addition, this study tests existence of mean reversion of crude oil futures prices to confirm the theory that profit margin hedging is more profitable than other strategies, such as always hedging or buying at expiration with spot price, if futures prices are mean reverting. The simulation results show that the expected utility of profit margin hedging higher than other strategies. Although we cannot find any evidence that crude oil futures prices follow mean reverting process, we can conclude that profit margin hedging can be optimal strategy in crude oil purchasing based on theoretical proof and simulation results.

• International Commerce and Information Review
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• v.14 no.2
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• pp.271-293
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• 2012

As service industry became more important, many of studies have been done on the role of service. Such studies has been researched focusing on the relationship between the service intensity in the economy and a country's productivity. Baumal(1967) suggested that service growth in economy would bring about decrease in productivity. However, the economy of developed countries encounter with the productivity growth as their economy grows, which phenomenon called Baumol's paradox. Oulton (1999, 2001) find out the reason of Baumol's paradox in a forward and backward chain effects. So, this paper is aimed at verifying the theory of Oulton (1999, 2001) for 13 OECD countries using panel data analysis. We find out that the intermediate knowledge-intensive service inputs cause a multifactor productivity growth.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.22-35
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• 2019

Utilizing fit theory in strategic human resource management, this study examines the impact of two HR practices on newcomer turnover rates. While there is a growing body of research identifying the linkage between high-performance work systems(HPWS) and improved organizational performance through higer employee commitment, little research addresses how specific mechanisms among the systems deliver different performances to organizations. Using management by objective(MBO) and job rotation in HPWS, we found a strong main effect of each practice-it decreases newcomer turnover rates. This main effect becomes stronger when one practice combined with another, showing synergy exists. Linking HPWS research to turnover, this study provides insightful evidence of interactions between MBO and job rotation for organizational performance.